Coronary microvascular dysfunction equivalent to left main coronary artery disease.

PubMed

Panç, Cafer; Kocaağa, Mehmet; Erdoğan, Onur; Sarıkaya, Remzi; Umman, Sabahattin

2017-04-01

Coronary microvascular dysfunction, also known as cardiac syndrome X, is a clinical syndrome presenting with typical angina and evidence of myocardial ischemia in the absence of flow-limiting stenosis on coronary angiography. Of patients undergoing coronary angiography due to suspected myocardial ischemia, 50% are found to have normal or near-normal coronary arteries. Described in this case report is a patient who developed hypotension and ST segment depressions during treadmill exercise test. Left main coronary artery or multivessel disease was suspected. Coronary angiography was normal, but coronary flow reserve measurement revealed severe microvascular dysfunction.

Systemic Artery to Pulmonary Vein Fistula After Right Upper Lobectomy Demonstrated by 4-Dimensional Flow Magnetic Resonance Imaging.

PubMed

Legras, Antoine; Azarine, Arshid; Poitier, Bastien; Messas, Emmanuel; Le Pimpec-Barthes, Françoise

2017-08-01

Postoperative systemic artery to pulmonary vein fistula is very rare. In this report, we describe an exceptional condition of both intrapulmonary arteriovenous fistula and systemic artery to pulmonary vein fistula, involving all right hemithoracic systemic arteries, inducing left-to-left shunt. This condition was responsible for heart failure, 24 years after a right upper lobectomy for inflammatory tumor. Investigations included computed tomographic angiography, arteriography, and four-dimensional flow magnetic resonance imaging. Differential diagnosis and management are discussed. Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Changes in ovarian reserve and ovarian blood flow in patients with polycystic ovary syndrome following laparoscopic ovarian drilling.

PubMed

Kamal, Nasser; Sanad, Zakaria; Elkelani, Osama; Rezk, Mohamed; Shawky, Mohamed; Sharaf, Abd-Elbar

2018-04-10

This prospective cohort study was conducted on 80 patients with clomiphene citrate (CC)-resistant polycystic ovary syndrome undergoing laparoscopic ovarian drilling (LOD). Pre- and post-LOD ovarian reserve parameters (anti-Mullerian hormone: AMH, ovarian volume: OV, and antral follicle count: AFC) and ovarian stromal blood flow indices (Vascularization index: VI, flow index: FI, and vascularization flow index: VFI) were measured to explore the effect of LOD and to find out the correlation between serum AMH and different clinical, hormonal, and ultrasonic variables. There was a highly significant reduction of the serum AMH (p < .001) after LOD with significant reduction in OV, AFC and vascular indices (VI, FI and VFI) of the right and left ovaries (p < .05). LOD significantly reduced ovarian reserve parameters (AMH, OV and AFC) and ovarian stromal blood flow indices (VI, FI and VFI) with no observed correlation between AMH levels and Doppler indices.

New therapy, new challenges: The effects of long-term continuous flow left ventricular assist device on inflammation.

PubMed

Grosman-Rimon, Liza; Billia, Filio; Fuks, Avi; Jacobs, Ira; A McDonald, Michael; Cherney, David Z; Rao, Vivek

2016-07-15

Surgically implanted continuous flow left ventricular assist devices (CF-LVADs) are currently used in patients with end-stage heart failure (HF). However, CF-LVAD therapy introduces a new set of complications and adverse events in these patients. Major adverse events with the CF-LVAD include right heart failure, vascular dysfunction, stroke, hepatic failure, and multi-organ failure, complications that may have inflammation as a common etiology. Our aim was to review the current evidence showing a relationship between these adverse events and elevated levels of inflammatory biomarkers in CF-LVAD recipients. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Wave energy patterns of counterpulsation: a novel approach with wave intensity analysis.

PubMed

Lu, Pong-Jeu; Yang, Chi-Fu Jeffrey; Wu, Meng-Yu; Hung, Chun-Hao; Chan, Ming-Yao; Hsu, Tzu-Cheng

2011-11-01

In counterpulsation, diastolic augmentation increases coronary blood flow and systolic unloading reduces left ventricular afterload. We present a new approach with wave intensity analysis to revisit and explain counterpulsation principles. In an acute porcine model, a standard intra-aortic balloon pump was placed in descending aorta in 4 pigs. We measured pressure and velocity with probes in left anterior descending artery and aorta during and without intra-aortic balloon pump assistance. Wave intensities of aortic and left coronary waves were derived from pressure and flow measurements with synchronization correction. We identified predominating waves in counterpulsation. In the aorta, during diastolic augmentation, intra-aortic balloon inflation generated a backward compression wave, with a "pushing" effect toward the aortic root that translated to a forward compression wave into coronary circulation. During systolic unloading, intra-aortic balloon pump deflation generated a backward expansion wave that "sucked" blood from left coronary bed into the aorta. While this backward expansion wave translated to reduced left ventricular afterload, the "sucking" effect resulted in left coronary blood steal, as demonstrated by a forward expansion wave in left anterior descending coronary flow. The waves were sensitive to inflation and deflation timing, with just 25 ms delay from standard deflation timing leading to weaker forward expansion wave and less coronary regurgitation. Intra-aortic balloon pumps generate backward-traveling waves that predominantly drive aortic and coronary blood flow during counterpulsation. Wave intensity analysis of arterial circulations may provide a mechanism to explain diastolic augmentation and systolic unloading of intra-aortic balloon pump counterpulsation. Copyright © 2011 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

Regional difference of microcirculation in patients with asymmetric hypertrophic cardiomyopathy: transthoracic Doppler coronary flow velocity reserve analysis.

PubMed

Tesic, Milorad; Djordjevic-Dikic, Ana; Beleslin, Branko; Trifunovic, Danijela; Giga, Vojislav; Marinkovic, Jelena; Petrovic, Olga; Petrovic, Milan; Stepanovic, Jelena; Dobric, Milan; Vukcevic, Vladan; Stankovic, Goran; Seferovic, Petar; Ostojic, Miodrag; Vujisic-Tesic, Bosiljka

2013-07-01

To evaluate, by noninvasive coronary flow velocity reserve (CFVR), whether patients with asymmetric hypertrophic cardiomyopathy (HC), with or without left ventricular outflow tract obstruction, demonstrate significant regional differences of CFVR. We evaluated 61 patients with HC (27 men; mean age 49 ± 16 years), including 20 patients with hypertrophic obstructive cardiomyopathy (HOCM) and 41 patients without obstruction (HCM). The control group included 20 age- and sex-matched subjects. Transthoracic Doppler echocardiography CFVR of the left anterior descending coronary artery (LAD) and the posterior descending coronary artery (PD) were performed, including calculation of relative CFVR as the ratio between CFVR LAD and CFVR PD. Compared with the controls, all the patients with HC had lower CFVR LAD (2.12 ± 0.53 vs 3.34 ± 0.67; P < .001) and CFVR PD (2.29 ± 0.49 vs 3.21 ± 0.65; P < .001). CFVR LAD in HOCM group in comparison with the HCM group was significantly lower (1.93 ± 0.42 vs 2.22 ± 0.55; P = .047), due to higher basal diastolic coronary flow velocities (0.40 ± 0.09 vs 0.33 ± 0.07 m/sec; P = .002), with similar hyperemic diastolic flow velocities (0.71 ± 0.16 vs 0.76 ± 0.19 m/sec; P = .330), respectively. There was no significant difference in CFVR PD between patients with HOCM and those with HCM (2.33 ± 0.46 vs 2.27 ± 0.50; P = .636), respectively. Relative CFVR was lower in the HOCM group compared with the HCM group (0.84 ± 0.16 vs 0.98 ± 0.14; P = .001). By multivariable regression analysis, left ventricular outflow tract gradient was the independent predictor of CFVR LAD (B = -0.24; P = .008) and relative CFVR (B = -0.34; P = .016). CFVR LAD and relative CFVR were significantly lower in patients with HOCM compared with patients with HCM. Regional differences of CFVR are present only in patients with significant left ventricular outflow tract obstruction, which suggests that obstruction per se, by increasing wall stress in basal conditions, leads to higher basal diastolic coronary flow velocities and results in lower CFVR in LAD compared with PD. Copyright © 2013 American Society of Echocardiography. Published by Mosby, Inc. All rights reserved.

End-diastolic flow reversal limits the efficacy of pediatric intra-aortic balloon pump counterpulsation.

PubMed

Bartoli, Carlo R; Rogers, Benjamin D; Ionan, Constantine E; Pantalos, George M

2014-05-01

Counterpulsation with an intra-aortic balloon pump (IABP) has not achieved the same success or clinical use in pediatric patients as in adults. In a pediatric animal model, IABP efficacy was investigated to determine whether IABP timing with a high-fidelity blood pressure signal may improve counterpulsation therapy versus a low-fidelity signal. In Yorkshire piglets (n = 19; weight, 13.0 ± 0.5 kg) with coronary ligation-induced acute ischemic left ventricular failure, pediatric IABPs (5 or 7 mL) were placed in the descending thoracic aorta. Inflation and deflation were timed with traditional criteria from low-fidelity (fluid-filled) and high-fidelity (micromanometer) blood pressure signals during 1:1 support. Aortic, carotid, and coronary hemodynamics were measured with pressure and flow transducers. Myocardial oxygen consumption was calculated from coronary sinus and arterial blood samples. Left ventricular myocardial blood flow and end-organ blood flow were measured with microspheres. Despite significant suprasystolic diastolic augmentation and afterload reduction at heart rates of 105 ± 3 beats per minute, left ventricular myocardial blood flow, myocardial oxygen consumption, the myocardial oxygen supply/demand relationship, cardiac output, and end-organ blood flow did not change. Statistically significant end-diastolic coronary, carotid, and aortic flow reversal occurred with IABP deflation. Inflation and deflation timed with a high-fidelity versus low-fidelity signal did not attenuate systemic flow reversal or improve the myocardial oxygen supply/demand relationship. Systemic end-diastolic flow reversal limited counterpulsation efficacy in a pediatric model of acute left ventricular failure. Adjustment of IABP inflation and deflation timing with traditional criteria and a high-fidelity blood pressure waveform did not improve IABP efficacy or attenuate flow reversal. End-diastolic flow reversal may limit the efficacy of IABP counterpulsation therapy in pediatric patients with traditional timing criteria. Investigation of alternative deflation timing strategies is warranted. Copyright © 2014 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

[Blood flow analysis in the left coronary artery in a patient with annulo-aortic-ectasia before and after Bentall's operation].

PubMed

Kondo, Y; Hanya, S; Hiyama, T; Ishihara, A

1990-12-01

It has not been established that Bentall's operation induces beneficial effect on a coronary circulation in a patient with Annulo-Aortic-Ectasia. Availability of a small subselective coronary Doppler catheter makes it possible to study the effects of the operation on coronary circulation. In a 49 year old man with Annulo-Aortic-Ectasia, phasic coronary flow velocity in the left main truncus was measured using a 3F steerable Doppler catheter (DC-101, Millar Inc.) pre- and postoperatively with assessment of vasodilator reserve capacity of individual coronary arteries. After the operation, the velocity wave form in the LMT changed to a diastolic-predominant normal pattern with a relatively small systolic component. That is, Bentall's operation caused a marked reduction of systolic- to diastolic flow component ratio from 0.32 to 0.19. The postoperative coronary flow configuration in the LMT was characterized by the presence of predominant diastolic spike. It coincided with "Water hammer wave" in the aortic pressure tracings caused by sudden closing of mechanical valve leaflets. Preoperative intracoronary papaverine increased the ratio of peak to resting velocity (coronary flow reserve) to 2.0 times at the rest, and 3.0 times after the operation. These results suggest that Bentall's operation seems to induce beneficial effect on the myocardial coronary circulation.

Recovery of distal coronary flow reserve in LAD and LCx after Y-Graft intervention assessed by transthoracic echocardiography

PubMed Central

2010-01-01

Background Y- graft (Y-G) is a graft formed by the Left Internal Mammary Artery (LIMA) connected to the Left Anterior Descending Artery (LAD) and by a free Right Internal Mammary Artery (RIMA) connected to LIMA and to a Marginal artery of Left Circumflex Artery (LCx). Aim of the work was to study the flow of this graft during a six months follow-up to assess whether the graft was able to meet the request of all the left coronary circulation, and to assess whether it could be done by evaluation of coronary flow reserve (CFR). Methods In 13 consecutive patients submitted to Y-G (13 men), CFR was measured in distal LAD and in distal LCx from 1 week after , every two months, up to six months after operation (a total of 8 tests for each patient) by means of transthoracic echocardiography (TTE) and Adenosine infusion (140 mcg/kg/min for 3-6 min). A Sequoia 256, Acuson-Siemens, was used. Contrast was used when necessary (Levovist 300 mg/ml solution at a rate of 0,5-1 ml/min). Max coronary flow diastolic velocity post-/pre-test ≥2 was considered normal CFR. Results Coronary arteriography revealed patency of both branches of Y-G after six months. Accuracy of TTE was 100% for LAD and 85% for LCx. Feasibility was 100% for LAD and 85% for LCx. CFR improved from baseline in LAD (2.21 ± 0.5 to 2.6 ± 0.5, p = 0.03) and in LCx (1.7 ± 1 to 2.12 ± 1, p = 0.05). CFR was under normal at baseline in 30% of patients vs 8% after six months in LAD (p = 0.027), and in 69% of patients vs 30% after six months in LCx (p = 0.066). Conclusion CFR in Y-G is sometimes reduced in both left territories postoperatively but it improves at six months follow-up. A follow-up can be done non-invasively by TTE and CFR evaluation. PMID:20716357

Performing and Interpreting Fractional Flow Reserve Measurements in Clinical Practice: An Expert Consensus Document

PubMed Central

Rudolph, Tanja; Rieber, Johannes; Eggebrecht, Holger; Richardt, Gert; Schmitz, Thomas; Werner, Nikos; Boenner, Florian; Möllmann, Helge

2017-01-01

Fractional flow reserve (FFR) measurements can determine the haemodynamic relevance of coronary artery stenoses. Current guidelines recommend their use in lesions in the absence of non-invasive proof of ischaemia. The prognostic impact of FFR has been evaluated in randomised trials, and it has been shown that revascularisation can be safely deferred if FFR is >0.80, while revascularisation of stenoses with FFR values ≤0.80 results in significantly lower event rates compared to medical treatment. Left main stenoses, aorto-ostial lesions, as well as patients with left ventricular hypertrophy and severely-impaired ejection fraction, have been excluded from large, randomised trials. While FFR measurements are relatively straightforward to perform, uncertainty about procedural logistics, as well as data acquisition and interpretation in specific situations, could explain why they are not widely used in clinical practice. We summarise the clinical data in support of FFR measurements, and provide recommendations for performing and interpreting the procedure. PMID:29588737

Coronary blood flow during percutaneous hemopump in patients at high risk for angioplasty

NASA Astrophysics Data System (ADS)

Geschwind, Herbert J.; Dubois-Rande, Jean Luc; Dupouy, Patrick J.; Larrazet, Fabrice S.; Kvasnicka, Jan; El-Ghalid, Ahmed; Deleuze, Philippe; Loisance, Daniel

1995-05-01

Hemopump is a ventricular assist device which is aimed at improving the management of high- risk patients for PTCA. The aim of the study was to access coronary blood flow velocity during hemopump. The hemopump was inserted percutaneously into the femoral artery. Coronary blood flow was measured with a 12 MHz Doppler-tipped guidewire proximal and distal to the stenosis before, during and after PTCA. Coronary vascular reserve was assessed by intracoronary 12 mg bolus injection of Papaverine. Collateral flow was assessed during balloon occlusion by inverted velocity signals below baseline. Eight patients aged 59 +/- 11 yrs, with unstable angina, a last patent vessel and/or major left ventricular dysfunction (EF < 0.20) had hemopump during PTCA of stenosis (86 +/- 14%) of the LAD (n equals 4) or the LCX (n equals 4). Collateral flow was slightly increased (+25 +/- 18%) by the Hemopump. Hemopump did not strongly affect coronary flow velocity, did not significantly increase collateral flow and increased slightly coronary vascular reserve.

Intraciliary calcium oscillations initiate vertebrate left-right asymmetry.

PubMed

Yuan, Shiaulou; Zhao, Lu; Brueckner, Martina; Sun, Zhaoxia

2015-03-02

Bilateral symmetry during vertebrate development is broken at the left-right organizer (LRO) by ciliary motility and the resultant directional flow of extracellular fluid. However, how ciliary motility is perceived and transduced into asymmetrical intracellular signaling at the LRO remains controversial. Previous work has indicated that sensory cilia and polycystin-2 (Pkd2), a cation channel, are required for sensing ciliary motility, yet their function and the molecular mechanism linking both to left-right signaling cascades are unknown. Here we report novel intraciliary calcium oscillations (ICOs) at the LRO that connect ciliary sensation of ciliary motility to downstream left-right signaling. Utilizing cilia-targeted genetically encoded calcium indicators in live zebrafish embryos, we show that ICOs depend on Pkd2 and are left-biased at the LRO in response to ciliary motility. Asymmetric ICOs occur with onset of LRO ciliary motility, thus representing the earliest known LR asymmetric molecular signal. Suppression of ICOs using a cilia-targeted calcium sink reveals that they are essential for LR development. These findings demonstrate that intraciliary calcium initiates LR development and identify cilia as a functional ion signaling compartment connecting ciliary motility and flow to molecular LR signaling. Copyright © 2015 Elsevier Ltd. All rights reserved.

Network-wise cerebral blood flow redistribution after 20 Hz rTMS on left dorso-lateral prefrontal cortex.

PubMed

Shang, Yuan-Qi; Xie, Jun; Peng, Wei; Zhang, Jian; Chang, Da; Wang, Ze

2018-04-01

The repetitive application of transcranial magnetic stimulation (rTMS) on left dorsolateral prefrontal cortex (DLPFC) has been consistently shown to be beneficial for treating various neuropsychiatric or neuropsychological disorders, but its neural mechanisms still remain unclear. The purpose of this study was to measure the effects of high-frequency left DLPFC rTMS using cerebral blood flow (CBF) collected from 40 young healthy subjects before and after applying 20 Hz left DLPFC rTMS or SHAM stimulations. Relative CBF (rCBF) changes before and after 20 Hz rTMS or SHAM were assessed with paired-t test. The results show that 20 Hz DLPFC rTMS induced CBF redistribution in the default mode network, including increased rCBF in left medial temporal cortex (MTC)/hippocampus, but reduced rCBF in precuneus and cerebellum. Meanwhile, SHAM stimulation didn't produce any rCBF changes. After controlling SHAM effects, only the rCBF increase in MTC/hippocampus remained. Those data suggest that the beneficial effects of high-frequency rTMS may be through a within-network rCBF redistribution. Copyright © 2018 Elsevier B.V. All rights reserved.

Distal left circumflex coronary artery flow reserve recorded by transthoracic Doppler echocardiography: a comparison with Doppler-wire

PubMed Central

Auriti, Antonio; Pristipino, Christian; Cianfrocca, Cinzia; Granatelli, Antonino; Guido, Vincenzo; Pelliccia, Francesco; Greco, Salvatore; Richichi, Giuseppe; Santini, Massimo

2007-01-01

Background Coronary flow reserve (CFR) recording by means of transthoracic echocardiography (TTDE) in all the main distal coronary arteries is a challenge for advanced echocardiography. Validation studies of TTDE versus Doppler-wire (DW) recordings are available for Left Anterior Descending artery (LAD) and the Posterior Descending coronary artery (PD), but lacking for the more technically challenging Left Circumflex coronary artery (LCx). Aim To evaluate the reliability of TTDE in assessing CFR in LCx when compared to the intracoronary Doppler flow-wire gold standard. Methods we evaluated 5 patients (age = 60 ± 9 years, 5 males) on LCx by TTDE and invasive CFR assessment. TTDE recording was performed using a low-frequency probe, with a four-chamber as a guiding 2D view. The 2 tests were performed on different days and in random order within 48 hours in a blind fashion. Vasodilator stimulus was adenosine, intravenously (140 γ/kg/min × 3–6 min) for TTDE and intracoronary (40 γ bolus) for DW recordings. Results CFR values on LCx ranged from 1.9 to 2.8 for DW, and from 2.0 to 3.0 for TTDE, with an overall correlation of R = 0,85 (p = 0,06); normal (CFR > 2.5) or abnormal (CFR < 2.5) value was concordantly identified by the 2 techniques in 4 out 5 cases (80%). Conclusion CFR of LCx artery can be obtained noninvasively with TTDE. PMID:17572907

Support with intra-aortic balloon pump vs. Impella2.5® and blood flow to the heart, brain and kidneys - an experimental porcine model of ischaemic heart failure.

PubMed

Møller-Helgestad, Ole K; Poulsen, Christian B; Christiansen, Evald H; Lassen, Jens F; Ravn, Hanne B

2015-01-15

Cardiogenic shock as a complication to an acute myocardial infarction has an unacceptably high death rate that has not changed for the last 15years. Mortality is partly related to organ hypoperfusion and mechanical assist devices are used for the most severe cases but we do not know which assist device is the best option. Therefore, we have investigated how an IABP and an Impella®-pump influenced blood flow to the brain, heart and kidneys, in a closed-chest porcine model of severe left ventricular failure. 13 pigs were anesthetised and left ventricular failure was induced by occluding the proximal LAD for 45min followed by 30min of reperfusion. Blood flow was measured in the carotid artery, the LAD, and the renal artery. The Impella® and IABP were inserted via the femoral arteries, and the two devices were tested individually and combined after induction of heart failure. Carotid- (p=0.01) and renal blood flow (p=0.045) were higher on Impella®-support, compared to no support. None of the devices altered the blood flow in the LAD. Cardiac power output (p<0.005) and left ventricular work (p<0.00) were also higher on Impella®-support compared to no support. Haemodynamics and blood flow to the brain and kidneys were significantly better on Impella®-support, suggesting that the Impella® is superior to the IABP in a state of ischaemia induced left ventricular failure. These data, however, needs to be confirmed in a proper clinical trial with patients in cardiogenic shock. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Southeast Expressway High Occupancy Vehicle Lane Evaluation Report

DOT National Transportation Integrated Search

1978-05-01

A non-separated concurrent-flow lane was instituted on Boston's Southeast Expressway on May 4, 1977. An eight-mile section of the left-most inbound lane was reserved for buses and carpools of three or more persons between the hours of 6:30 a.m. and 9...

Implantable physiologic controller for left ventricular assist devices with telemetry capability.

PubMed

Asgari, Siavash S; Bonde, Pramod

2014-01-01

Rotary type left ventricular assist devices have mitigated the problem of durability associated with earlier pulsatile pumps and demonstrated improved survival. However, the compromise is the loss of pulsatility due to continuous flow and retained percutaneous driveline leading to increased mortality and morbidity. Lack of pulsatility is implicated in increased gastrointestinal bleeding, aortic incompetence, and diastolic hypertension. We present a novel, wirelessly powered, ultra-compact, implantable physiologic controller capable of running a left ventricular assist device in a pulsatile mode with wireless power delivery. The schematic of our system was laid out on a circuit board to wirelessly receive power and run a left ventricular assist device with required safety and backup measures. We have embedded an antenna and wireless network for telemetry. Multiple signal processing steps and controlling algorithm were incorporated. The controller was tested in in vitro and in vivo experiments. The controller drove left ventricular assist devices continuously for 2 weeks in an in vitro setup and in vivo without any failure. Our controller is more power efficient than the current Food and Drug Administration-approved left ventricular assist device controllers. When used with electrocardiography synchronization, the controller allowed on-demand customization of operation with instantaneous flow and revolutions per minute changes, resulting in a pulsatile flow with adjustable pulse pressure. Our test results prove the system to be remarkably safe, accurate, and efficient. The unique combination of wireless powering and small footprint makes this system an ideal totally implantable physiologic left ventricular assist device system. Copyright © 2014 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

[Lung perfusion studies after percutaneous closure of patent ductus arteriosus using the Amplatzer Duct Occluder in children].

PubMed

Parra-Bravo, José Rafael; Apolonio-Martínez, Adriana; Estrada-Loza, María de Jesús; Beirana-Palencia, Luisa Gracia; Ramírez-Portillo, César Iván

2015-01-01

The closure of patent ductus arteriosus with multiple devices has been associated with a reduction in lung perfusion. We evaluated the pulmonary perfusion after percutaneous closure of patent ductus arteriosus with the Amplatzer Duct Occluder device using perfusion lung scan. Thirty patients underwent successful percutaneous patent ductus arteriosus occlusions using the Amplatzer Duct Occluder device were included in this study. Lung perfusion scans were preformed 6 months after the procedure. Peak flow velocities and protrusion of the device were analyzed by Doppler echocardiography. A left lung perfusion<40% was considered abnormal. The device implantation was successful in all patients. Average perfusion of left lung was 44.7±4.9% (37.8-61.4). Five patients (16.6%) showed decreased perfusion of the left lung. Age, low weight, the length of the ductus arteriosus and the minimum and maximum diameter/length of the ductus arteriosus ratio were statistically significant in patients with abnormalities of lung perfusion. It was observed protrusion the device in 6 patients with a higher maximum flow rate in the left pulmonary artery. The left lung perfusion may be compromised after percutaneous closure of patent ductus arteriosus with the Amplatzer Duct Occluder. The increased flow velocity in the origin of the left pulmonary artery can be a poor indicator of reduction in pulmonary perfusion and can occur in the absence of protrusion of the device. Copyright © 2014 Instituto Nacional de Cardiología Ignacio Chávez. Published by Masson Doyma México S.A. All rights reserved.

Integration of Wall Motion, Coronary Flow Velocity, and Left Ventricular Contractile Reserve in a Single Test: Prognostic Value of Vasodilator Stress Echocardiography in Patients with Diabetes.

PubMed

Cortigiani, Lauro; Huqi, Alda; Ciampi, Quirino; Bombardini, Tonino; Bovenzi, Francesco; Picano, Eugenio

2018-06-01

Coronary flow velocity reserve (CFVR) and left ventricular contractile reserve (LVCR) have demonstrated prognostic importance in patients with diabetes. The aim of this study was to investigate the prognostic contribution of combined evaluation of CFVR and LVCR in patients with diabetes with nonischemic stress echocardiography. Three hundred seventy-five patients with diabetes (mean age, 68 ± 9 years) with nonischemic dipyridamole stress echocardiography underwent assessment of CFVR of the left anterior descending coronary artery (prospectively) and LVCR with left ventricular force (retrospectively) in a multicenter study. On receiver operating characteristic analysis, LVCR ≤ 1.1 was the best prognostic predictor and was considered an abnormal value. CFVR was abnormal (≤2) in 139 patients (37%), LVCR in 156 (42%), neither in 157 (42%), and both in 77 (21%). During a median follow-up period of 16 months, 86 major adverse cardiac events occurred: 16 deaths, 13 myocardial infarctions, and 57 revascularizations. Multivariate prognostic indicators were CFVR ≤ 2 (P < .0001), age (P = .03), and LVCR ≤ 1.1 (P = .04). The 3-year rate of major adverse cardiac events was 63% in patients with both abnormal CFVR and LVCR, 42% in those with abnormal CFVR only, 19% in those with abnormal LVCR only, and 10% in patients with both normal CFVR and LVCR. The 3-year hard event rate was 3% in patients with both normal CFVR and LVCR, fivefold higher in patients with abnormal CFVR or LVCR only, and ninefold higher in patients with both abnormal CFVR and LVCR. Patients with diabetes with nonischemic dipyridamole stress echocardiography may still have significant risk in presence of abnormal CFVR and/or LVCR, which assess the underlying, largely unrelated, microvascular and myocardial components of coronary circulation. Copyright © 2017 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.

Impact of lesion characteristics on the prediction of optimal poststent fractional flow reserve.

PubMed

Ando, Hirohiko; Takashima, Hiroaki; Suzuki, Akihiro; Sakurai, Shinichiro; Kumagai, Soichiro; Kurita, Akiyoshi; Waseda, Katsuhisa; Amano, Tetsuya

2016-12-01

Poststent fractional flow reserve (FFR) is a useful indicator of optimal percutaneous coronary intervention, and higher poststent FFR is associated with favorable long-term clinical outcome. However, little is known about the factors influencing poststent FFR. The purpose of this study was to determine the impact of lesion characteristics on poststent FFR. For patients who had scheduled stent implantation for stable angina, FFR measurements at maximum hyperemia were performed before and after coronary stent implantation. As one of lesion characteristics, the FFR pressure drop pattern was evaluated and classified as either an abrupt or a gradual pattern according to the pullback curve of FFR. A total of 205 lesions with physiological significant stenosis were evaluated. Fractional flow reserve value increased from 0.67±0.10 to 0.87±0.07 after stent implantation. Optimal poststent FFR was achieved in 75 lesions (36.6%). Logistic regression analysis demonstrated that optimal poststent FFR was positively correlated with an abrupt pressure drop pattern (hazard ratio [HR] 2.11, 95% CI 1.06-4.15, P=.03) and prestent FFR (HR 1.04, 95% CI 1.03-2.04, P=.03; per 0.1 increase), and negatively correlated with lesion localization to the left anterior descending artery (HR 0.18, 95% CI 0.09-0.36, P<.0001). The c statistic for predicting optimal poststent FFR was 0.763 (95% CI 0.702-0.819). Abrupt pressure drop patterns, prestent FFR, and lesion localization to the left anterior descending artery were independent predictors of optimal poststent FFR. Copyright © 2016 Elsevier Inc. All rights reserved.

Continuous-flow cardiac assistance: effects on aortic valve function in a mock loop.

PubMed

Tuzun, Egemen; Rutten, Marcel; Dat, Marco; van de Vosse, Frans; Kadipasaoglu, Cihan; de Mol, Bas

2011-12-01

As the use of left ventricular assist devices (LVADs) to treat end-stage heart failure has become more widespread, leaflet fusion--with resul-tant aortic regurgitation--has been observed more frequently. To quantitatively assess the effects of nonpulsatile flow on aortic valve function, we tested a continuous-flow LVAD in a mock circulatory system (MCS) with an interposed valve. To mimic the hemodynamic characteristics of LVAD patients, we utilized an MCS in which a Jarvik 2000 LVAD was positioned at the base of a servomotor-operated piston pump (left ventricular chamber). We operated the LVAD at 8000 to 12,000 rpm, changing the speed in 1000-rpm increments. At each speed, we first varied the outflow resistance at a constant stroke volume, then varied the stroke volume at a constant outflow resistance. We measured the left ventricular pressure, aortic pressure, pump flow, and total flow, and used these values to compute the change, if any, in the aortic duty cycle (aortic valve open time) and transvalvular aortic pressure loads. Validation of the MCS was demonstrated by the simulation of physiologic pressure and flow waveforms. At increasing LVAD speeds, the mean aortic pressure load steadily increased, while the aortic duty cycle steadily decreased. Changes were consistent for each MCS experimental setting, despite variations in stroke volume and outflow resistance. Increased LVAD flow results in an impaired aortic valve-open time due to a pressure overload above the aortic valve. Such an overload may initiate structural changes, causing aortic leaflet fusion and/or regurgitation. Copyright © 2011 Elsevier Inc. All rights reserved.

Coronary microvascular dysfunction after myocardial infarction: increased coronary zero flow pressure both in the infarcted and in the remote myocardium is mainly related to left ventricular filling pressure.

PubMed

Van Herck, P L; Carlier, S G; Claeys, M J; Haine, S E; Gorissen, P; Miljoen, H; Bosmans, J M; Vrints, C J

2007-10-01

To investigate the underlying mechanisms of a decreased coronary flow reserve after myocardial infarction (MI) by analysing the characteristics of the diastolic hyperaemic coronary pressure-flow relationship. Prospective study. Tertiary care hospital. 68 patients with a recent MI and 27 patients with stable angina pectoris (AP; control group). The intercept with the pressure axis (the zero flow pressure or Pzf) and slope index of the pressure-flow relationship (SIPF) were calculated from the simultaneously recorded hyperaemic intracoronary blood flow velocity and aortic pressure after successful coronary stenting. A stepwise increase in Pzf from AP (14.6 (8.0) mm Hg), over non-Q-wave MI (22.5 (9.1) mm Hg), to Q-wave MI (37.1 (12.9) mm Hg; p<0.001) was observed. Similar changes in Pzf were found in a reference artery perfusing the non-infarcted myocardium. Multivariate analysis showed that in both regions the left ventricular end-diastolic pressure (LVEDP) was the most important determinant of the Pzf. The SIPF was not statistically different in the treated vessel between patients with MI and AP, but was increased in MI patients with a markedly increased LVEDP. After an MI, the coronary pressure-flow relationship is shifted to the right both in the infarcted and in the non-infarcted remote myocardium, as shown by the increased Pzf. The correlation with Pzf suggests that elevated left ventricular filling pressures contribute to the impediment of myocardial perfusion in patients with infarction.

Effect of Permanent Right Internal Mammary Artery Closure on Coronary Collateral Function and Myocardial Ischemia.

PubMed

Stoller, Michael; Seiler, Christian

2017-06-01

The objective of this study is to test the effect of permanent right internal mammary artery device closure on coronary collateral function and myocardial ischemia. This was a prospective, open-label clinical trial in 50 patients with coronary artery disease. The primary study end point was coronary collateral flow index as obtained during a 1-minute proximal right coronary artery (RCA) and left coronary artery balloon occlusion at baseline before and at follow-up examination 6 weeks after distal right internal mammary artery device closure. Collateral flow index is the ratio between simultaneously recorded mean coronary occlusive pressure divided by mean aortic pressure, both subtracted by central venous pressure. Secondary study end points were fractional flow reserve during vessel patency, the quantitative intracoronary ECG ST-segment elevation, and angina pectoris during the same 1-minute coronary occlusion. Collateral flow index in the untreated RCA and left coronary artery changed from 0.071±0.082 at baseline to 0.132±0.117 ( P <0.0001) at follow-up examination and from 0.106±0.092 to 0.081±0.079 ( P =0.29), respectively. RCA fractional flow reserve increased significantly ( P =0.0029) from baseline to follow-up examination, despite deferral of coronary intervention in all patients. There was a decrease in intracoronary ECG ST-elevation during RCA occlusion from baseline to follow-up examination ( P =0.0015); it did not change in the left coronary artery. Angina pectoris during RCA occlusion tended to occur in fewer patients at follow-up versus baseline examination ( P =0.06). Permanent right internal mammary artery device closure seems to augment extracardiac ipsilateral coronary supply to the effect of reducing ischemia in the dependent myocardial region. URL: http://www.clinicaltrials.gov. Unique identifier: NCT02475408. © 2017 The Authors.

Continuous monitoring of regional function by a miniaturized ultrasound transducer allows early quantification of low-grade myocardial ischemia.

PubMed

Hyler, Stefan; Pischke, Søren E; Halvorsen, Per Steinar; Espinoza, Andreas; Bergsland, Jacob; Tønnessen, Tor Inge; Fosse, Erik; Skulstad, Helge

2015-04-01

Sensitive methods for the early detection of myocardial dysfunction are still needed, as ischemia is a leading cause of decreased ventricular function during and after heart surgery. The aim of this study was to test the hypothesis that low-grade ischemia could be detected quantitatively by a miniaturized epicardial ultrasound transducer (Ø = 3 mm), allowing continuous monitoring. In 10 pigs, transducers were positioned in the left anterior descending and circumflex coronary artery areas. Left ventricular pressure was obtained by a micromanometer. The left internal mammary artery was grafted to the left anterior descending coronary artery, which was occluded proximal to the anastomosis. Left internal mammary artery flow was stepwise reduced by 25%, 50%, and 75% for 18 min each. From the transducers, M-mode traces were obtained, allowing continuous tissue velocity traces and displacement measurements. Regional work was assessed as left ventricular pressure-displacement loop area. Tissue lactate measured from intramyocardial microdialysis was used as reference method to detect ischemia. All steps of coronary flow reduction demonstrated reduced peak systolic velocity (P < .05) and regional work (P < .01).The decreases in peak systolic velocity and regional work were closely related to the degree of ischemia, demonstrated by their correlations with lactate (R = -0.74, P < .01, and R = -0.64, P < .01, respectively). The circumflex coronary artery area was not affected by any of the interventions. The epicardially attached miniaturized ultrasound transducer allowed the precise detection of different levels of coronary flow reduction. The results also showed a quantitative and linear relationship among coronary flow, ischemia, and myocardial function. Thus, the ultrasound transducer has the potential to improve the monitoring of myocardial ischemia and to detect graft failure during and after heart surgery. Copyright © 2015 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.

Early signs that predict later haemodynamically significant patent ductus arteriosus.

PubMed

Engür, Defne; Deveci, Murat; Türkmen, Münevver K

2016-03-01

Our aim was to determine the optimal cut-off values, sensitivity, specificity, and diagnostic power of 12 echocardiographic parameters on the second day of life to predict subsequent ductal patency. We evaluated preterm infants, born at ⩽32 weeks of gestation, starting on their second day of life, and they were evaluated every other day until ductal closure or until there were clinical signs of re-opening. We measured transductal diameter; pulmonary arterial diastolic flow; retrograde aortic diastolic flow; pulsatility index of the left pulmonary artery and descending aorta; left atrium and ventricle/aortic root ratio; left ventricular output; left ventricular flow velocity time integral; mitral early/late diastolic flow; and superior caval vein diameter and flow as well as performed receiver operating curve analysis. Transductal diameter (>1.5 mm); pulmonary arterial diastolic flow (>25.6 cm/second); presence of retrograde aortic diastolic flow; ductal diameter by body weight (>1.07 mm/kg); left pulmonary arterial pulsatility index (⩽0.71); and left ventricle to aortic root ratio (>2.2) displayed high sensitivity and specificity (p0.9). Parameters with moderate sensitivity and specificity were as follows: left atrial to aortic root ratio; left ventricular output; left ventricular flow velocity time integral; and mitral early/late diastolic flow ratio (p0.05) had low diagnostic value. Left pulmonary arterial pulsatility index, left ventricle/aortic root ratio, and ductal diameter by body weight are useful adjuncts offering a broader outlook for predicting ductal patency.

Quantification of coronary flow reserve in patients with ischaemic and non-ischaemic cardiomyopathy and its association with clinical outcomes.

PubMed

Majmudar, Maulik D; Murthy, Venkatesh L; Shah, Ravi V; Kolli, Swathy; Mousavi, Negareh; Foster, Courtney R; Hainer, Jon; Blankstein, Ron; Dorbala, Sharmila; Sitek, Arkadiusz; Stevenson, Lynne W; Mehra, Mandeep R; Di Carli, Marcelo F

2015-08-01

Patients with left ventricular systolic dysfunction frequently show abnormal coronary vascular function, even in the absence of overt coronary artery disease. Moreover, the severity of vascular dysfunction might be related to the aetiology of cardiomyopathy.We sought to determine the incremental value of assessing coronary vascular dysfunction among patients with ischaemic (ICM) and non-ischaemic (NICM) cardiomyopathy at risk for adverse cardiovascular outcomes. Coronary flow reserve (CFR, stress/rest myocardial blood flow) was quantified in 510 consecutive patients with rest left ventricular ejection fraction (LVEF) ≤45% referred for rest/stress myocardial perfusion PET imaging. The primary end point was a composite of major adverse cardiovascular events (MACE) including cardiac death, heart failure hospitalization, late revascularization, and aborted sudden cardiac death.Median follow-up was 8.2 months. Cox proportional hazards model was used to adjust for clinical variables. The annualized MACE rate was 26.3%. Patients in the lowest two tertiles of CFR (CFR ≤ 1.65) experienced higher MACE rates than those in the highest tertile (32.6 vs. 15.5% per year, respectively, P = 0.004), irrespective of aetiology of cardiomyopathy. Impaired coronary vascular function, as assessed by reduced CFR by PET imaging, is common in patients with both ischaemic and non-ischaemic cardiomyopathy and is associated with MACE. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.

Assessing hemispheric specialization for processing arithmetic skills in adults: A functional transcranial doppler ultrasonography (fTCD) study.

PubMed

Connaughton, Veronica M; Amiruddin, Azhani; Clunies-Ross, Karen L; French, Noel; Fox, Allison M

2017-05-01

A major model of the cerebral circuits that underpin arithmetic calculation is the triple-code model of numerical processing. This model proposes that the lateralization of mathematical operations is organized across three circuits: a left-hemispheric dominant verbal code; a bilateral magnitude representation of numbers and a bilateral Arabic number code. This study simultaneously measured the blood flow of both middle cerebral arteries using functional transcranial Doppler ultrasonography to assess hemispheric specialization during the performance of both language and arithmetic tasks. The propositions of the triple-code model were assessed in a non-clinical adult group by measuring cerebral blood flow during the performance of multiplication and subtraction problems. Participants were 17 adults aged between 18-27 years. We obtained laterality indices for each type of mathematical operation and compared these in participants with left-hemispheric language dominance. It was hypothesized that blood flow would lateralize to the left hemisphere during the performance of multiplication operations, but would not lateralize during the performance of subtraction operations. Hemispheric blood flow was significantly left lateralized during the multiplication task, but was not lateralized during the subtraction task. Compared to high spatial resolution neuroimaging techniques previously used to measure cerebral lateralization, functional transcranial Doppler ultrasonography is a cost-effective measure that provides a superior temporal representation of arithmetic cognition. These results provide support for the triple-code model of arithmetic processing and offer complementary evidence that multiplication operations are processed differently in the adult brain compared to subtraction operations. Copyright © 2017 Elsevier B.V. All rights reserved.

To shunt or not to shunt? An experimental study comparing temporary vascular shunts and venous ligation as damage control techniques for vascular trauma.

PubMed

Marinho de Oliveira Góes Junior, Adenauer; de Campos Vieira Abib, Simone; de Seixas Alves, Maria Teresa; Venerando da Silva Ferreira, Paulo Sérgio; Carvalho de Andrade, Mariseth

2014-04-01

To evaluate vascular flow through temporary vascular shunts inserted into peripheral arteries and veins and the repercussion, on the arterial perfusion, of venous ligation and venous shunt insertion in an experimental model for damage control. Experimental study in pigs. Animals were distributed in 5 groups: group 1, right external iliac artery (EIA) shunting and right external iliac vein (EIV) ligation; group 2, right EIA shunting and right EIV shunting; group 3, right EIV ligation; group 4, right EIV shunting; group 5, no vascular shunting and no venous ligation. Flowmeters were used to measure vascular flow on right and left external iliac vessels, and blood samples were collected from the EIVs for biochemical analysis. A right anterior limb biopsy was performed before shock. Hemorrhagic shock was induced through the external right jugular vein, until the vascular flow through right iliac external artery shunt or right iliac external vein shunt (group 4) ceased or until the animal's death. After the end of the experiments, biopsies of bilateral hind limb were obtained for histologic analysis. For statistical analysis, Microsoft Office Excel 2007 and BioEstat 5.0 (2007) were used. In the absence of hemorrhagic shock, venous ligation (group 1) was associated with a 38.8% reduction (P < 0.05) and venous shunting with a 28.4% reduction on the vascular flow through the arterial shunt. When associated with hemorrhagic shock, the mean vascular flow on the right EIA was 13 mL/min and on the left EIA was 41.2 mL/min; on group 2, the right EIA flow was 8.5 mL/min and the left EIA flow was 8.1 mL/min. When associated with hemorrhagic shock, the pO2 was 25.8 mm Hg on right EIV and 33.8 mm Hg on the left EIV for group 1 (P < 0.05), whereas for group 2, the pO2 was 22.6 mm Hg on right EIV and 22.8 mm Hg on the left EIV. On group 1, serum potassium was 3.84 mEq/L on the right EIV and 3.96 mEq/L on the left EIV, whereas on group 2, it was 7.1 mEq/L on the right EIV and 5.88 mEq/L on the left EIV (P < 0.05). In the developed experimental model, venous shunting, when compared with venous ligation, offered less resistance to vascular flow through the arterial shunt and allowed a more efficient limb venous drainage than simple vein ligature. Copyright © 2014 Elsevier Inc. All rights reserved.

FFR analysis of blood flow through a stenosed Left Anterior Descending Artery

NASA Astrophysics Data System (ADS)

Pasupathi, Jawahar; Arul Prakash, K.

2017-11-01

The numerical analyisis of blood flow through a stenosed tapering Left Anterior Descending (LAD) artery was done using Streamwise Upwind Petrov Galerkin (SUPG) method to obtain the clinical parameters such as Fractional Flow reserve (FFR) and Wall Shear Stress (WSS). The geometry was considered to be a straight tapering cylindrical duct with the severity of stenosis modeled using a curve equation based on the reduction in diameter at the stenosed region. Poiseuille velocity profile was given at the inlet such that at each time step the product of mean velocity and the inlet area gives the realistic flow rate through the LAD. The simulation was done for 30,50 and 70 percent reduction in cross-section of LAD. The average pressure values across the stenosis was used to quantify FFR. The FFR increased with higher pressure ratio across the stenosis, which is a result of increased severity of stenosis. The velocity gradients that are responsible for the shear stress at the walls were found to be dependent on the shape of the stenosis, i.e., the diameter and its length.

Transthoracic ultrasonic tissue indices identify patients with severe left anterior descending artery stenosis. Correlation with fractional flow reserve. Pilot study.

PubMed

Dobrowolski, Piotr; Kowalski, Mirosław; Rybicka, Justyna; Lech, Agnieszka; Tyczyński, Paweł; Witkowski, Adam; Hoffman, Piotr

2016-01-01

The aim of this study was to evaluate the potential clinical application of ultrasonic tissue indices, with a focus on systolic strain (SS) and systolic strain rate (SSR) parameters derived from transthoracic echocardiography, in the assessment of left anterior descending artery (LAD) stenosis. The data of 30 patients with significant LAD stenosis were analysed. All patients underwent transthoracic echocardiography to obtain systolic myocardial velocity (Sm), longitudinal SS, and SSR from basal, mid, and apical segments of anterior and inferior walls in two-chamber apical view. Severity of LAD obstruction was measured by means of fractional flow reserve (FFR) during coronary catheterisation. Systolic velocities, strain, and strain rate measured in basal, middle, and apical segments of the anterior left ventricular (LV) wall were lower when compared to those obtained from the corresponding, i.e. unaffected, inferior LV wall. There was a significant correlation between FFR and the value of SS, SSR characterising the apical LV segment of the anterior wall (r = -0.583, p = 0.01; r = -0.598, p = 0.01, respectively). Moreover, we found significant correlation between FFR and Sm in the mid-segment of the LV anterior wall (r = 0.611, p = 0.009). We conclude that SS and SSR obtained from the apical segment of the anterior LV wall may be related to the severity of LAD stenosis.

Experimental and numeric investigation of Impella pumps as cavopulmonary assistance for a failing Fontan.

PubMed

Haggerty, Christopher M; Fynn-Thompson, Francis; McElhinney, Doff B; Valente, Anne Marie; Saikrishnan, Neelakantan; Del Nido, Pedro J; Yoganathan, Ajit P

2012-09-01

This study sought to evaluate the performance of microaxial ventricular assist devices for the purposes of supporting failing Fontan physiology by decreasing central venous pressure. Three Abiomed Impella pumps (Abiomed, Inc, Danvers, Mass) were evaluated in a mock circulatory system of the Fontan circuit. The local response of pressures and flows to pump function was assessed as a function of pump speed and pulmonary vascular resistance at a high baseline central venous pressure. For one device, subsequent modeling studies were conducted using a lumped parameter model of the single ventricle circuit. The left ventricular devices (Impella 2.5, 5.0) were shown to be suboptimal as single device solutions for cavopulmonary support. The small area of these devices relative to vessel diameter led to significant flow recirculation without an obstructive separator in place. Furthermore, downstream pressure augmentation adversely affected the pressure in the superior vena cava. The use of 2 devices would be mandatory for successful support. The right-sided device (Impella RP), whose outflow was positioned in the left pulmonary artery, demonstrated decreased flow recirculation and did not impede superior caval venous flow. Although static pressure is still required to drive flow through the opposite lung, numeric modeling demonstrated the potential for modest but significant improvements in lowering the central venous pressure (2-8 mm Hg). Left-sided microaxial pumps are not well suited for cavopulmonary support because of severe flow recirculation and the need for multiple devices. The right-ventricular Impella device provides improved performance by directing flow into the pulmonary artery, resulting in modest decreases in central venous pressure. Copyright © 2012 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

Coronary microvascular dysfunction after myocardial infarction: increased coronary zero flow pressure both in the infarcted and in the remote myocardium is mainly related to left ventricular filling pressure

PubMed Central

Van Herck, P L; Carlier, S G; Claeys, M J; Haine, S E; Gorissen, P; Miljoen, H; Bosmans, J M; Vrints, C J

2007-01-01

Objective To investigate the underlying mechanisms of a decreased coronary flow reserve after myocardial infarction (MI) by analysing the characteristics of the diastolic hyperaemic coronary pressure–flow relationship. Design Prospective study. Setting Tertiary care hospital. Patients 68 patients with a recent MI and 27 patients with stable angina pectoris (AP; control group). Main outcome measures The intercept with the pressure axis (the zero flow pressure or Pzf) and slope index of the pressure–flow relationship (SIPF) were calculated from the simultaneously recorded hyperaemic intracoronary blood flow velocity and aortic pressure after successful coronary stenting. Results A stepwise increase in Pzf from AP (14.6 (8.0) mm Hg), over non‐Q‐wave MI (22.5 (9.1) mm Hg), to Q‐wave MI (37.1 (12.9) mm Hg; p<0.001) was observed. Similar changes in Pzf were found in a reference artery perfusing the non‐infarcted myocardium. Multivariate analysis showed that in both regions the left ventricular end‐diastolic pressure (LVEDP) was the most important determinant of the Pzf. The SIPF was not statistically different in the treated vessel between patients with MI and AP, but was increased in MI patients with a markedly increased LVEDP. Conclusions After an MI, the coronary pressure–flow relationship is shifted to the right both in the infarcted and in the non‐infarcted remote myocardium, as shown by the increased Pzf. The correlation with Pzf suggests that elevated left ventricular filling pressures contribute to the impediment of myocardial perfusion in patients with infarction. PMID:17395671

Effects of right ventricular hemodynamic burden on intraventricular flow in tetralogy of fallot: an echocardiographic contrast particle imaging velocimetry study.

PubMed

Kutty, Shelby; Li, Ling; Danford, David A; Houle, Helene; Datta, Saurabh; Mancina, Joel; Xiao, Yunbin; Pedrizzetti, Gianni; Porter, Thomas R

2014-12-01

The purpose of this investigation was to test the hypothesis that flow patterns in the right ventricle are abnormal in patients with repaired tetralogy of Fallot (TOF). High-resolution echocardiographic contrast particle imaging velocimetry was used to investigate rotation intensity and kinetic energy dissipation of right ventricular (RV) flow in patients with TOF compared with normal controls. Forty-one subjects (16 with repaired TOF and varying degrees of RV dilation and 25 normal controls) underwent prospective contrast imaging using the lipid-encapsulated microbubble (Definity) on Sequoia systems. A mechanical index of 0.4, three-beat high-frame rate (>60 Hz) captures, and harmonic frequencies were used. Rotation intensity and kinetic energy dissipation of flow in the right and left ventricles were studied (Hyperflow). Ventricular volumes and ejection fractions in all subjects were derived from same-day cardiac magnetic resonance (CMR). Measurable planar maps were obtained for the left ventricle in 14 patients and the right ventricle in 10 patients among those with TOF and for the left ventricle in 23 controls and the right ventricle in 21 controls. Compared with controls, the TOF group had higher RV indexed end-diastolic volumes (117.8 ± 25.5 vs 88 ± 15.4 mL/m(2), P < .001) and lower RV ejection fractions (44.6 ± 3.6% vs 51.8 ± 3.6%, P < .001). Steady-streaming (heartbeat-averaged) flow rotation intensities were higher in patients with TOF for the left ventricle (0.4 ± 0.13 vs 0.29 ± 0.08, P = .012) and the right ventricle (0.53 ± 0.15 vs 0.26 ± 0.12, P < .001), whereas kinetic energy dissipation in TOF ventricles was lower (for the left ventricle, 0.51 ± 0.29 vs 1.52 ± 0.69, P < .001; for the right ventricle, 0.4 ± 0.24 vs 1.65 ± 0.91, P < .001). It is feasible to characterize RV and left ventricular flow parameters and planar maps in adolescents and adults with repaired TOF using echocardiographic contrast particle imaging velocimetry. Intraventricular flow patterns in the abnormal and/or enlarged right ventricle in patients with TOF differ from those in normal young adults. The rotation intensity and energy dissipation trends in this investigation suggest that they may be quantitative markers of RV and left ventricular compliance abnormalities in patients with repaired TOF. This hypothesis merits further investigation. Copyright © 2014 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.

Spiral Laminar Flow: a Survey of a Three-Dimensional Arterial Flow Pattern in a Group of Volunteers.

PubMed

Stonebridge, P A; Suttie, S A; Ross, R; Dick, J

2016-11-01

Spiral laminar flow was suggested as potentially the predominant arterial blood flow pattern many years ago. Computational fluid dynamics and flow rig testing have suggested there are advantages to spiral laminar flow. The aim of this study was to identify whether spiral laminar is the predominant flow pattern in a cohort of volunteers. This study included 42 volunteers (mean age 66.8 years). Eleven arterial sites were examined, comprising bilateral examination of the common carotid artery, internal carotid artery, external carotid artery, common femoral artery, superficial femoral artery, and the infra renal aorta. The presence or absence of spiral laminar flow, the peak systolic velocity, and the rotational velocity were assessed by colour Duplex scanning. The incidence of spiral laminar flow ranged from 81% in the internal carotid artery to 90% in the common carotid artery and the infra renal aorta. Overall, in 58% of all right-sided arteries the rotation was clockwise and 42% anticlockwise. In all left-sided arteries these numbers were reversed. Analysis on the basis of volunteer rather than examination site showed that 41/42 (97%) had more sites with spiral laminar flow than without. Only one volunteer had more sites exhibiting non-spiral laminar flow. Spiral laminar flow was the predominant flow pattern in the study population. This observation raises questions and suggests a need for further studies concerning the form and function of the left ventricle, the geometry of the arterial system, and the function of the arterial wall. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

Doppler indexes of left ventricular systolic and diastolic flow and central pulse pressure in relation to renal resistive index.

PubMed

Kuznetsova, Tatiana; Cauwenberghs, Nicholas; Knez, Judita; Thijs, Lutgarde; Liu, Yan-Ping; Gu, Yu-Mei; Staessen, Jan A

2015-04-01

The cardio-renal interaction occurs via hemodynamic and humoral factors. Noninvasive assessment of renal hemodynamics is currently possible by assessment of renal resistive index (RRI) derived from intrarenal Doppler arterial waveforms as ((peak systolic velocity - end-diastolic velocity)/peak systolic velocity). Limited information is available regarding the relationship between RRI and cardiac hemodynamics. We investigated these associations in randomly recruited subjects from a general population. In 171 participants (48.5% women; mean age, 52.2 years), using pulsed wave Doppler, we measured RRI (mean, 0.60) and left ventricular outflow tract (LVOT) and transmitral (E and A) blood flow peak velocities and its velocity time integrals (VTI). Using carotid applanation tonometry, we measured central pulse pressure and arterial stiffness indexes such as augmentation pressure and carotid-femoral pulse wave velocity. In stepwise regression analysis, RRI independently and significantly increased with female sex, age, body weight, brachial pulse pressure, and use of β-blockers, whereas it decreased with body height and mean arterial pressure. In multivariable-adjusted models with central pulse pressure and arterial stiffness indexes as the explanatory variables, we observed a significant and positive correlation of RRI only with central pulse pressure (P < 0.0001). Among the Doppler indexes of left ventricular blood flow, RRI was significantly and positively associated with LVOT and E peak velocities (P ≤ 0.012) and VTIs (P ≤ 0.010). We demonstrated that in unselected subjects RRI was significantly associated with central pulse pressure and left ventricular systolic and diastolic Doppler blood flow indexes. Our findings imply that in addition to the anthropometric characteristics, cardiac hemodynamic factors influence the intrarenal arterial Doppler waveform patterns. © American Journal of Hypertension, Ltd 2014. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Right Ventricular Perfusion: Physiology and Clinical Implications.

PubMed

Crystal, George J; Pagel, Paul S

2018-01-01

Regulation of blood flow to the right ventricle differs significantly from that to the left ventricle. The right ventricle develops a lower systolic pressure than the left ventricle, resulting in reduced extravascular compressive forces and myocardial oxygen demand. Right ventricular perfusion has eight major characteristics that distinguish it from left ventricular perfusion: (1) appreciable perfusion throughout the entire cardiac cycle; (2) reduced myocardial oxygen uptake, blood flow, and oxygen extraction; (3) an oxygen extraction reserve that can be recruited to at least partially offset a reduction in coronary blood flow; (4) less effective pressure-flow autoregulation; (5) the ability to downregulate its metabolic demand during coronary hypoperfusion and thereby maintain contractile function and energy stores; (6) a transmurally uniform reduction in myocardial perfusion in the presence of a hemodynamically significant epicardial coronary stenosis; (7) extensive collateral connections from the left coronary circulation; and (8) possible retrograde perfusion from the right ventricular cavity through the Thebesian veins. These differences promote the maintenance of right ventricular oxygen supply-demand balance and provide relative resistance to ischemia-induced contractile dysfunction and infarction, but they may be compromised during acute or chronic increases in right ventricle afterload resulting from pulmonary arterial hypertension. Contractile function of the thin-walled right ventricle is exquisitely sensitive to afterload. Acute increases in pulmonary arterial pressure reduce right ventricular stroke volume and, if sufficiently large and prolonged, result in right ventricular failure. Right ventricular ischemia plays a prominent role in these effects. The risk of right ventricular ischemia is also heightened during chronic elevations in right ventricular afterload because microvascular growth fails to match myocyte hypertrophy and because microvascular dysfunction is present. The right coronary circulation is more sensitive than the left to α-adrenergic-mediated constriction, which may contribute to its greater propensity for coronary vasospasm. This characteristic of the right coronary circulation may increase its vulnerability to coronary vasoconstriction and impaired right ventricular perfusion during administration of α-adrenergic receptor agonists.

2-D left ventricular flow estimation by combining speckle tracking with Navier-Stokes-based regularization: an in silico, in vitro and in vivo study.

PubMed

Gao, Hang; Bijnens, Nathalie; Coisne, Damien; Lugiez, Mathieu; Rutten, Marcel; D'hooge, Jan

2015-01-01

Despite the availability of multiple ultrasound approaches to left ventricular (LV) flow characterization in two dimensions, this technique remains in its childhood and further developments seem warranted. This article describes a new methodology for tracking the 2-D LV flow field based on ultrasound data. Hereto, a standard speckle tracking algorithm was modified by using a dynamic kernel embedding Navier-Stokes-based regularization in an iterative manner. The performance of the proposed approach was first quantified in synthetic ultrasound data based on a computational fluid dynamics model of LV flow. Next, an experimental flow phantom setup mimicking the normal human heart was used for experimental validation by employing simultaneous optical particle image velocimetry as a standard reference technique. Finally, the applicability of the approach was tested in a clinical setting. On the basis of the simulated data, pointwise evaluation of the estimated velocity vectors correlated well (mean r = 0.84) with the computational fluid dynamics measurement. During the filling period of the left ventricle, the properties of the main vortex obtained from the proposed method were also measured, and their correlations with the reference measurement were also calculated (radius, r = 0.96; circulation, r = 0.85; weighted center, r = 0.81). In vitro results at 60 bpm during one cardiac cycle confirmed that the algorithm properly measures typical characteristics of the vortex (radius, r = 0.60; circulation, r = 0.81; weighted center, r = 0.92). Preliminary qualitative results on clinical data revealed physiologic flow fields. Copyright © 2015 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

The feasibility of measuring renal blood flow using transesophageal echocardiography in patients undergoing cardiac surgery.

PubMed

Yang, Ping-Liang; Wong, David T; Dai, Shuang-Bo; Song, Hai-Bo; Ye, Ling; Liu, Jin; Liu, Bin

2009-05-01

There is no reliable method to monitor renal blood flow intraoperatively. In this study, we evaluated the feasibility and reproducibility of left renal blood flow measurements using transesophageal echocardiography during cardiac surgery. In this prospective noninterventional study, left renal blood flow was measured with transesophageal echocardiography during three time points (pre-, intra-, and postcardiopulmonary bypass) in 60 patients undergoing cardiac surgery. Sonograms from 6 subjects were interpreted by 2 blinded independent assessors at the time of acquisition and 6 mo later. Interobserver and intraobserver reproducibility were quantified by calculating variability and intraclass correlation coefficients. Patients with Doppler angles of >30 degrees (20 of 60 subjects) were eliminated from renal blood flow measurements. Left renal blood flow was successfully measured and analyzed in 36 of 60 (60%) subjects. Both interobserver and intraobserver variability were <10%. Interobserver and intraobserver reproducibility in left renal blood flow measurements were good to excellent (intraclass correlation coefficients 0.604-0.999). Left renal arterial luminal diameter for the pre, intra, and postcardiopulmonary bypass phases, ranged from 3.8 to 4.1 mm, renal arterial velocity from 25 to 35 cm/s, and left renal blood flow from 192 to 299 mL/min. In patients undergoing cardiac surgery, it was feasible in 60% of the subjects to measure left renal blood flow using intraoperative transesophageal echocardiography. The interobserver and intraobserver reproducibility of renal blood flow measurements was good to excellent.

Patient-specific CFD models for intraventricular flow analysis from 3D ultrasound imaging: Comparison of three clinical cases.

PubMed

Bavo, A M; Pouch, A M; Degroote, J; Vierendeels, J; Gorman, J H; Gorman, R C; Segers, P

2017-01-04

As the intracardiac flow field is affected by changes in shape and motility of the heart, intraventricular flow features can provide diagnostic indications. Ventricular flow patterns differ depending on the cardiac condition and the exploration of different clinical cases can provide insights into how flow fields alter in different pathologies. In this study, we applied a patient-specific computational fluid dynamics model of the left ventricle and mitral valve, with prescribed moving boundaries based on transesophageal ultrasound images for three cardiac pathologies, to verify the abnormal flow patterns in impaired hearts. One case (P1) had normal ejection fraction but low stroke volume and cardiac output, P2 showed low stroke volume and reduced ejection fraction, P3 had a dilated ventricle and reduced ejection fraction. The shape of the ventricle and mitral valve, together with the pathology influence the flow field in the left ventricle, leading to distinct flow features. Of particular interest is the pattern of the vortex formation and evolution, influenced by the valvular orifice and the ventricular shape. The base-to-apex pressure difference of maximum 2mmHg is consistent with reported data. We used a CFD model with prescribed boundary motion to describe the intraventricular flow field in three patients with impaired diastolic function. The calculated intraventricular flow dynamics are consistent with the diagnostic patient records and highlight the differences between the different cases. The integration of clinical images and computational techniques, therefore, allows for a deeper investigation intraventricular hemodynamics in patho-physiology. Copyright © 2016 Elsevier Ltd. All rights reserved.

Novel Surgical Technique for Coronary Fistulas With Proximal Origin.

PubMed

Uchida, Tetsuro; Hamasaki, Azumi; Kuroda, Yoshinori; Ohba, Eiichi; Yamashita, Atsushi; Sadahiro, Mitsuaki

2017-09-01

Postoperative residual shunting is a significant concern in patients with coronary arteriovenous fistulas, especially in fistulas originating from the proximal left coronary artery, because of the limited surgical field. We report a case of fistulas originating from the proximal coronary artery in a 63-year-old woman in whom the ascending aorta and pulmonary artery were transected to obtain good surgical exposure. After complete transection of both great arteries, fistulas arising from the left main trunk were ligated externally, and their intracardiac openings were closed internally. Postoperative examination revealed no residual shunt flow. Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Impaired cerebral blood flow networks in temporal lobe epilepsy with hippocampal sclerosis: A graph theoretical approach.

PubMed

Sone, Daichi; Matsuda, Hiroshi; Ota, Miho; Maikusa, Norihide; Kimura, Yukio; Sumida, Kaoru; Yokoyama, Kota; Imabayashi, Etsuko; Watanabe, Masako; Watanabe, Yutaka; Okazaki, Mitsutoshi; Sato, Noriko

2016-09-01

Graph theory is an emerging method to investigate brain networks. Altered cerebral blood flow (CBF) has frequently been reported in temporal lobe epilepsy (TLE), but graph theoretical findings of CBF are poorly understood. Here, we explored graph theoretical networks of CBF in TLE using arterial spin labeling imaging. We recruited patients with TLE and unilateral hippocampal sclerosis (HS) (19 patients with left TLE, and 21 with right TLE) and 20 gender- and age-matched healthy control subjects. We obtained all participants' CBF maps using pseudo-continuous arterial spin labeling and analyzed them using the Graph Analysis Toolbox (GAT) software program. As a result, compared to the controls, the patients with left TLE showed a significantly low clustering coefficient (p=0.024), local efficiency (p=0.001), global efficiency (p=0.010), and high transitivity (p=0.015), whereas the patients with right TLE showed significantly high assortativity (p=0.046) and transitivity (p=0.011). The group with right TLE also had high characteristic path length values (p=0.085), low global efficiency (p=0.078), and low resilience to targeted attack (p=0.101) at a trend level. Lower normalized clustering coefficient (p=0.081) in the left TLE and higher normalized characteristic path length (p=0.089) in the right TLE were found also at a trend level. Both the patients with left and right TLE showed significantly decreased clustering in similar areas, i.e., the cingulate gyri, precuneus, and occipital lobe. Our findings revealed differing left-right network metrics in which an inefficient CBF network in left TLE and vulnerability to irritation in right TLE are suggested. The left-right common finding of regional decreased clustering might reflect impaired default-mode networks in TLE. Copyright © 2016 Elsevier Inc. All rights reserved.

Pulmonary function tests do not predict mortality in patients undergoing continuous-flow left ventricular assist device implantation.

PubMed

Bedzra, Edo K S; Dardas, Todd F; Cheng, Richard K; Pal, Jay D; Mahr, Claudius; Smith, Jason W; Shively, Kent; Masri, S Carolina; Levy, Wayne C; Mokadam, Nahush A

2017-12-01

To investigate the effect of pulmonary function testing on outcomes after continuous flow left ventricular assist device implantation. A total of 263 and 239 patients, respectively, had tests of forced expiratory volume in 1 second and diffusing capacity of the lungs for carbon monoxide preoperatively for left ventricular assist device implantations between July 2005 and September 2015. Kaplan-Meier analysis and multivariable Cox regressions were performed to evaluate mortality. Patients were analyzed in a single cohort and across 5 groups. Postoperative intensive care unit and hospital lengths of stay were evaluated with negative binomial regressions. There is no association of forced expiratory volume in 1 second and diffusing capacity of the lungs for carbon monoxide with survival and no difference in mortality at 1 and 3 years between the groups (log rank P = .841 and .713, respectively). Greater values in either parameter were associated with decreased hospital lengths of stay. Only diffusing capacity of the lungs for carbon monoxide was associated with increased intensive care unit length of stay in the group analysis (P = .001). Ventilator times, postoperative pneumonia, reintubation, and tracheostomy rates were similar across the groups. Forced expiratory volume in 1 second and diffusing capacity of the lungs for carbon monoxide are not associated with operative or long-term mortality in patients undergoing continuous flow left ventricular assist device implantation. These findings suggest that these abnormal pulmonary function tests alone should not preclude mechanical circulatory support candidacy. Copyright © 2017 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

The Electrophysiologic Effects of Acute Mitral Regurgitation in a Canine Model.

PubMed

Lawrance, Christopher P; Henn, Matthew C; Miller, Jacob R; Kopek, Michael A; Zhang, Andrew J; Schuessler, Richard B; Damiano, Ralph J

2017-04-01

Atrial fibrillation (AF) occurs in 30% of patients with mitral regurgitation referred for surgical intervention. However, the underlying mechanisms in this population are poorly understood. This study examined the effects of acute left atrial volume overload on atrial electrophysiology and the inducibility of AF. Ten canines underwent insertion of an atrioventricular shunt between the left ventricle and left atrium. Shunt and aortic flows were calculated, and the shunt was titrated to a shunt fraction to 40% to 50% of cardiac output. An epicardial plaque with 250 bipolar electrodes was used to determine activation and refractory periods. Biatrial pressures and volumes, conduction times, and atrial fibrillation inducibility were recorded. Data were collected at baseline and 20 minutes after shunt opening and closure. Mean shunt flow was 1.3 ± 0.5 L/min with a shunt fraction of 43% ± 6% simulating moderate to severe mitral regurgitation. Compared with baseline, left atrial volumes and maximum pressures increased by 27% and 29%, respectively, after shunt opening. Biatrial effective refractory periods did not change significantly after shunt opening or closure. Conduction times increased by 9% with shunt opening and returned to baseline after closure. AF duration or inducibility did not change with shunt opening. This canine model of mitral regurgitation demonstrated that acute left atrial volume overload did not increase the inducibility of atrial arrhythmias in contrast with experimental and clinical findings of chronic left atrial volume overload. This suggests that the substrates for AF in patients with mitral regurgitation are a result of chronic remodeling. Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Comparative utility of gated myocardial perfusion imaging and transthoracic coronary flow reserve for the assessment of coronary artery disease in patients with left bundle branch block.

PubMed

Pavlovic, Smiljana; Sobic-Saranovic, Dragana; Djordjevic-Dikic, Ana; Beleslin, Branko; Stepanovic, Jelena; Artiko, Vera; Giga, Vojislav; Petrasinovic, Zorica; Ostojic, Miodrag; Vujisic-Tesic, Bosiljka; Obradovic, Vladimir

2010-04-01

To compare the diagnostic utility of gated single-photon emission computed tomography (SPECT) methoxy isobutyl isonitrile (MIBI) myocardial perfusion imaging and transthoracic Doppler echocardiography (TTDE) coronary flow reserve (CFR) to coronary angiography for detecting coronary artery disease (CAD) in patients with left bundle branch block (LBBB). Forty-three patients with complete LBBB and an intermediate pretest probability for CAD underwent dipyridamole stress TTDE and gated SPECT MIBI during the same session and coronary angiography within a month. The parameters of myocardial perfusion (summed stress score, summed difference scores) regional wall function (wall motion score, wall thickening score) and ejection fraction were derived using the 17-segment model and 4D-MSPECT software. TTDE variables included peak flow velocity at rest and during hyperemia in left anterior descending artery (LAD), based on which CFR was calculated (normal>2). Perfusion ischemic scores were significantly higher in group 1 with angiographic evidence of greater than 50% LAD stenosis compared with group 2 with less than 50% LAD stenosis (summed stress score 12.4+/-5.5 vs. 8.3+/-3.5, P<0.05, summed difference score 3.7+/-1.2 vs. 1.1+/-0.3, P<0.01, respectively). Left ventricular regional wall function and ejection fraction were not different between the two groups. CFR was significantly lower in group 1 than in group 2 (1.65+/-0.21 vs. 2.31+/-0.28, P<0.001). Gated SPECT MIBI and CFR had similar sensitivity (88 vs. 88%), specificity (80 vs. 84%), and accuracy (84 vs. 86%) for detecting CAD in patients with LBBB. The agreement between the two methods was 85%. Our results show comparable diagnostic utility and high agreement between gated SPECT MIBI perfusion imaging and TTDE CFR assessment for detecting CAD in patients with LBBB. The advantage of gated SPECT MIBI over TTDE CFR measurements is the ability to assess the perfusion abnormalities in multiple vascular territories during the same procedure, which is convenient for detecting multi-vessel disease in patients with LBBB.

Deceleration time of left ventricular outflow tract flow as a simple surrogate marker for central haemodynamics at rest and as well as during exercise.

PubMed

Cho, In-Jeong; Shim, Chi Young; Moon, Sun-Ha; Lee, Hyun-Jin; Hong, Geu-Ru; Chung, Namsik; Ha, Jong-Won

2017-05-01

The shape and duration of left ventricular outflow tract (LVOT) flow has not been applied to assess the central haemodynamics, although LVOT flow is confronted with afterload of arterial system during systole. The aim of this study was to evaluate whether the LVOT flow parameters are related with central systolic blood pressure (BP) and arterial compliance at rest and as well as during exercise. We studied 258 subjects (175 females, age 61 ± 11 years) with normal left ventricular (LV) systolic function who underwent supine bicycle stress echocardiography and arterial tonometry simultaneously at rest and at peak exercise. Deceleration time (DT) of LVOT flow and RR interval were measured and deceleration time corrected for heart rate (DTc) was calculated. Peripheral and central haemodynamic parameters including systolic and diastolic BP, and augmentation index at a heart rate of 75 (AIx@75) were assessed using radial artery tonometry. Carotid femoral pulse wave velocity (PWV) was measured. Deceleration time corrected for heart rate was independently associated with central systolic BP and AIx@75 at rest (P < 0.001 and 0.006). Similarly, it also showed significant independent correlations with central systolic BP and AIx@75 during peak exercise (P = 0.006 and P = 0.021). In addition, DTc which measured both at rest and at peak exercise demonstrated significant positive correlations with PWV, suggesting association of prolonged DTc with arterial stiffening (P = 0.023 and P = 0.005). Prolongation of LVOT flow DTc represents raised central systolic BP and increased arterial stiffness not only at rest but also during exercise. Therefore, central aortic pressures and arterial stiffness influence the DT of LVOT flow at rest as well as during exercise in individuals with normal LV systolic function. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For permissions please email: journals.permissions@oup.com.

Saline-Induced Coronary Hyperemia: Mechanisms and Effects on Left Ventricular Function.

PubMed

De Bruyne, Bernard; Adjedj, Julien; Xaplanteris, Panagiotis; Ferrara, Angela; Mo, Yujing; Penicka, Martin; Floré, Vincent; Pellicano, Mariano; Toth, Gabor; Barbato, Emanuele; Duncker, Dirk J; Pijls, Nico H J

2017-04-01

During thermodilution-based assessment of volumetric coronary blood flow, we observed that intracoronary infusion of saline increased coronary flow. This study aims to quantify the extent and unravel the mechanisms of saline-induced hyperemia. Thirty-three patients were studied; in 24 patients, intracoronary Doppler flow velocity measurements were performed at rest, after intracoronary adenosine, and during increasing infusion rates of saline at room temperature through a dedicated catheter with 4 lateral side holes. In 9 patients, global longitudinal strain and flow propagation velocity were assessed by transthoracic echocardiography during a prolonged intracoronary saline infusion. Taking adenosine-induced maximal hyperemia as reference, intracoronary infusion of saline at rates of 5, 10, 15, and 20 mL/min induced 6%, 46%, 111%, and 112% of maximal hyperemia, respectively. There was a close agreement of maximal saline- and adenosine-induced coronary flow reserve (intraclass correlation coefficient, 0.922; P <0.001). The same infusion rates given through 1 end hole (n=6) or in the contralateral artery (n=6) did not induce a significant increase in flow velocity. Intracoronary saline given on top of an intravenous infusion of adenosine did not further increase flow. Intracoronary saline infusion did not affect blood pressure, systolic, or diastolic left ventricular function. Heart rate decreased by 15% during saline infusion ( P =0.021). Intracoronary infusion of saline at room temperature through a dedicated catheter for coronary thermodilution induces steady-state maximal hyperemia at a flow rate ≥15 mL/min. These findings open new possibilities to measure maximal absolute coronary blood flow and minimal microcirculatory resistance. © 2017 American Heart Association, Inc.

Coronary bypass flow during use of intraaortic balloon pumping and left ventricular assist device.

PubMed

Tedoriya, T; Kawasuji, M; Sakakibara, N; Takemura, H; Watanabe, Y; Hetzer, R

1998-08-01

Intraaortic balloon pumping (IABP) and left ventricular assist device (LVAD) are used for left ventricular support when low cardiac output occurs after a coronary bypass operation for serious coronary artery disease. There are hemodynamic differences in blood flow in various kinds of coronary artery bypass grafts, caused by their inherent physiologic characteristics. The hemodynamic effects of left ventricular assistance with IABP and LVAD on blood flow through various coronary artery bypass grafts were investigated. An ascending aorta-coronary bypass graft (ACB), an internal thoracic artery, and a descending aorta-coronary bypass graft were anastomosed to the left anterior descending coronary artery in a canine model. In this experimental model, the blood flow to the same coronary bed in the three types of grafts could be evaluated. Blood flow in the left anterior descending coronary artery through the three types of coronary bypass grafts was studied in this model during or in the absence of ventricular assistance. In the control study, the systolic blood flow did not differ among the three types of grafts, but the diastolic flow decreased in the following order: with the ACB, the internal thoracic artery, and the descending aorta-coronary bypass graft. The systolic flow during IABP and LVAD was similar to the control flows. Use of IABP increased the diastolic flow by 75.3%+/-12.4% of the control value in the ACB, 37.9%+/-25.0% in the internal thoracic artery, and 21.2%+/-11.4% in the descending aorta-coronary bypass graft. The LVAD increased the diastolic flow by 97.7%+/-18.7% of the control value in the ACB, 64.5%+/-25.7% in the internal thoracic artery, and 63.0%+/-27.9% in the descending aorta-coronary bypass graft. The diastolic blood flows in the left anterior descending coronary artery and the three types of grafts were significantly greater with IABP than the control values, and significantly greater with LVAD than with IABP and the control values. The degrees of increase of diastolic flows in the left anterior descending coronary artery and the ACB with IABP and LVAD were significantly greater than in the arterial grafts (p < 0.01). The diastolic flows in the internal thoracic artery and descending aorta-coronary bypass graft increased less than in the native left anterior descending coronary artery and ACB during left ventricular assistance, particularly with IABP. It is important for the selection of tactics for the management of catastrophic status after coronary bypass grafting to consider the hemodynamic characteristics of the graft.

Verification of a computational cardiovascular system model comparing the hemodynamics of a continuous flow to a synchronous valveless pulsatile flow left ventricular assist device.

PubMed

Gohean, Jeffrey R; George, Mitchell J; Pate, Thomas D; Kurusz, Mark; Longoria, Raul G; Smalling, Richard W

2013-01-01

The purpose of this investigation is to use a computational model to compare a synchronized valveless pulsatile left ventricular assist device with continuous flow left ventricular assist devices at the same level of device flow, and to verify the model with in vivo porcine data. A dynamic system model of the human cardiovascular system was developed to simulate the support of a healthy or failing native heart from a continuous flow left ventricular assist device or a synchronous pulsatile valveless dual-piston positive displacement pump. These results were compared with measurements made during in vivo porcine experiments. Results from the simulation model and from the in vivo counterpart show that the pulsatile pump provides higher cardiac output, left ventricular unloading, cardiac pulsatility, and aortic valve flow as compared with the continuous flow model at the same level of support. The dynamic system model developed for this investigation can effectively simulate human cardiovascular support by a synchronous pulsatile or continuous flow ventricular assist device.

Verification of a computational cardiovascular system model comparing the hemodynamics of a continuous flow to a synchronous valveless pulsatile flow left ventricular assist device

PubMed Central

Gohean, Jeffrey R.; George, Mitchell J.; Pate, Thomas D.; Kurusz, Mark; Longoria, Raul G.; Smalling, Richard W.

2012-01-01

The purpose of this investigation is to utilize a computational model to compare a synchronized valveless pulsatile left ventricular assist device to continuous flow left ventricular assist devices at the same level of device flow, and to verify the model with in vivo porcine data. A dynamic system model of the human cardiovascular system was developed to simulate support of a healthy or failing native heart from a continuous flow left ventricular assist device or a synchronous, pulsatile, valveless, dual piston positive displacement pump. These results were compared to measurements made during in vivo porcine experiments. Results from the simulation model and from the in vivo counterpart show that the pulsatile pump provides higher cardiac output, left ventricular unloading, cardiac pulsatility, and aortic valve flow as compared to the continuous flow model at the same level of support. The dynamic system model developed for this investigation can effectively simulate human cardiovascular support by a synchronous pulsatile or continuous flow ventricular assist device. PMID:23438771

Improving left ventricular segmentation in four-dimensional flow MRI using intramodality image registration for cardiac blood flow analysis.

PubMed

Gupta, Vikas; Bustamante, Mariana; Fredriksson, Alexandru; Carlhäll, Carl-Johan; Ebbers, Tino

2018-01-01

Assessment of blood flow in the left ventricle using four-dimensional flow MRI requires accurate left ventricle segmentation that is often hampered by the low contrast between blood and the myocardium. The purpose of this work is to improve left-ventricular segmentation in four-dimensional flow MRI for reliable blood flow analysis. The left ventricle segmentations are first obtained using morphological cine-MRI with better in-plane resolution and contrast, and then aligned to four-dimensional flow MRI data. This alignment is, however, not trivial due to inter-slice misalignment errors caused by patient motion and respiratory drift during breath-hold based cine-MRI acquisition. A robust image registration based framework is proposed to mitigate such errors automatically. Data from 20 subjects, including healthy volunteers and patients, was used to evaluate its geometric accuracy and impact on blood flow analysis. High spatial correspondence was observed between manually and automatically aligned segmentations, and the improvements in alignment compared to uncorrected segmentations were significant (P < 0.01). Blood flow analysis from manual and automatically corrected segmentations did not differ significantly (P > 0.05). Our results demonstrate the efficacy of the proposed approach in improving left-ventricular segmentation in four-dimensional flow MRI, and its potential for reliable blood flow analysis. Magn Reson Med 79:554-560, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

Association of HeartMate II left ventricular assist device flow estimate with thermodilution cardiac output.

PubMed

Hasin, Tal; Huebner, Marianne; Li, Zhuo; Brown, Daniel; Stulak, John M; Boilson, Barry A; Joyce, Lyle; Pereira, Naveen L; Kushwaha, Sudhir S; Park, Soon J

2014-01-01

Cardiac output (CO) assessment is important in treating patients with heart failure. Durable left ventricular assist devices (LVADs) provide essentially all CO. In currently used LVADs, estimated device flow is generated by a computerized algorithm. However, LVAD flow estimate may be inaccurate in tracking true CO. We correlated LVAD (HeartMate II) flow with thermodilution CO during postoperative care (day 2-10 after implant) in 81 patients (5,616 paired measurements). Left ventricular assist device flow and CO correlated with a low correlation coefficient (r = 0.42). Left ventricular assist device readings were lower than CO measurements by approximately 0.36 L/min, trending for larger difference with higher values. Left ventricular assist device flow measurements showed less temporal variability compared with CO. Grouping for simultaneous measured blood pressure (BP < 60, 60-70, 70-80, 80-90, and ≥90), the correlation of CO with LVAD flow differed (R = 0.42, 0.67, 0.48, 0.32, 0.32, respectively). Indicating better correlation when mean blood pressure is 60 to 70 mm Hg. Left ventricular assist device flow generally trends with measured CO, but large variability exists, hence flow measures should not be assumed to equal with CO. Clinicians should take into account variables such as high CO, BP, and opening of the aortic valve when interpreting LVAD flow readout. Direct flow sensors incorporated in the LVAD system may allow for better estimation.

Relationship of neonatal cerebral blood flow velocity asymmetry with early motor, cognitive and language development in term infants.

PubMed

Wu, Ying-Chin; Hsieh, Wu-Shiun; Hsu, Chyong-Hsin; Chiu, Nan-Chang; Chou, Hung-Chieh; Chen, Chien-Yi; Peng, Shinn-Forng; Hung, Han-Yang; Chang, Jui-Hsing; Chen, Wei J; Jeng, Suh-Fang

2013-05-01

The objective of this study was to examine the relationships of Doppler cerebral blood flow velocity (CBFV) asymmetry measures with developmental outcomes in term infants. Doppler CBFV parameters (peak systolic velocity [PSV] and mean velocity [MV]) of the bilateral middle cerebral arteries of 52 healthy term infants were prospectively examined on postnatal days 1-5, and then their motor, cognitive and language development was evaluated with the Bayley Scales of Infant and Toddler Development, Third Edition, at 6, 12, 18 and 24 months of age. The left CBFV asymmetry measure (PSV or MV) was calculated by subtracting the right-side value from the left-side value. Left CBFV asymmetry measures were significantly positively related to motor scores at 6 (r = 0.3-0.32, p < 0.05) and 12 (r = 0.35, p < 0.05) months of age, but were not related to cognitive or language outcome. Thus, the leftward hemodynamic status of the middle cerebral arteries, as measured by cranial Doppler ultrasound in the neonatal period, predicts early motor outcome in term infants. Copyright © 2013 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Left main coronary artery disease: pathophysiology, diagnosis, and treatment.

PubMed

Collet, Carlos; Capodanno, Davide; Onuma, Yoshinobu; Banning, Adrian; Stone, Gregg W; Taggart, David P; Sabik, Joseph; Serruys, Patrick W

2018-06-01

The advent of coronary angiography in the 1960s allowed for the risk stratification of patients with stable angina. Patients with unprotected left main coronary artery disease have an increased risk of death related to the large amount of myocardium supplied by this vessel. Although coronary angiography remains the preferred imaging modality for the evaluation of left main coronary artery stenosis, this technique has important limitations. Angiograms of the left main coronary artery segment can be difficult to interpret, and almost one-third of patients can be misclassified when fractional flow reserve is used as the reference. In patients with clinically significant unprotected left main coronary artery disease, surgical revascularization was shown to improve survival compared with medical therapy and has been regarded as the treatment of choice for unprotected left main coronary artery disease. Two large-scale clinical trials published in 2016 support the usefulness of catheter-based revascularization in selected patients with unprotected left main coronary artery disease. In this Review, we describe the pathophysiology of unprotected left main coronary artery disease, discuss diagnostic approaches in light of new noninvasive and invasive imaging techniques, and detail risk stratification models to aid the Heart Team in the decision-making process for determining the best revascularization strategy for these patients.

Exploring energy loss by vector flow mapping in children with ventricular septal defect: Pathophysiologic significance.

PubMed

Honda, Takashi; Itatani, Keiichi; Takanashi, Manabu; Kitagawa, Atsushi; Ando, Hisashi; Kimura, Sumito; Oka, Norihiko; Miyaji, Kagami; Ishii, Masahiro

2017-10-01

Vector flow mapping is a novel echocardiographic flow visualization method, and it has enabled us to quantitatively evaluate the energy loss in the left ventricle (intraventricular energy loss). Although intraventricular energy loss is assumed to be a part of left ventricular workload itself, it is unclear what this parameter actually represents. The aim of the present study was to elucidate the characteristics of intraventricular energy loss. We enrolled 26 consecutive children with ventricular septal defect (VSD). On echocardiography vector flow mapping, intraventricular energy loss was measured in the apical 3-chamber view. We measured peak energy loss and averaged energy loss in the diastolic and systolic phases, and subsequently compared these parameters with catheterization parameters and serum brain natrium peptide (BNP) level. Diastolic, peak, and systolic energy loss were strongly and positively correlated with right ventricular systolic pressure (r=0.76, 0.68, and 0.56, p<0.0001, = 0.0001, and 0.0029, respectively) and right ventricular end diastolic pressure (r=0.55, 0.49, and 0.49, p=0.0038, 0.0120, and 0.0111, respectively). In addition, diastolic, peak, and systolic energy loss were significantly correlated with BNP (r=0.75, 0.69 and 0.49, p<0.0001, < 0.0001, and=0.0116, respectively). In children with VSD, elevated right ventricular pressure is one of the factors that increase energy loss in the left ventricle. The results of the present study encourage further studies in other study populations to elucidate the characteristics of intraventricular energy loss for its possible clinical application. Copyright © 2017 Elsevier B.V. All rights reserved.

Traumatic common hepatic artery injury causing isolated right hepatic ischemia due to a left accessory artery. A case report.

PubMed

Fernandes, Eduardo; Pedrazzani, Corrado; Gerena, Marielia; Omi, Ellen

2017-01-01

Hepatic arterial liver flow is renowned for its redundancy. Previous studies have demonstrated that the common hepatic artery is not essential for liver survival. We present a case of a 31year-old involved in a high-speed motor vehicle accident whose liver survived thanks to the presence of an accessory hepatic artery. We present the case of a 31year-old male who sustained a traumatic injury of the proper hepatic artery following a motor vehicle accident. The patient suffered temporary right liver lobe ischemia due to the presence of an accessory left hepatic artery. This resulted in the selective formation of 'biliary lakes' distinctively within the territory of the right hepatic artery supply. Simultaneously the patient developed a pseudo-aneurysm of the proper hepatic artery which required radiology intervention. At the time of pseudo-aneurysm embolisation, a rich network of arterial collaterals had formed between the accessory left hepatic and the inferior phrenic artery. On follow up the biliary lakes to the right lobe had resolved, but a small area at the periphery of the right lobe had encountered atrophy. This case report is an 'in vivo' demonstration of liver resilience to arterial flow re-distribution and demonstrates the ability of the biliary epithelium to recover from and ischemic injury. Parenchymal liver survival is mostly independent from flow within the common hepatic artery. Acute and chronic liver parenchyma changes following interruption of hepatic artery flow can still occur. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Left ventricular to left atrial communication secondary to a paraaortic abscess: color flow Doppler documentation.

PubMed

Fisher, E A; Estioko, M R; Stern, E H; Goldman, M E

1987-07-01

Aortic root abscess occurs frequently in aortic prosthetic valve infective endocarditis. The present echocardiographic report documents a ruptured abscess that led to a direct communication between the left ventricular outflow tract and the left atrium confirmed by real-time (color flow) Doppler imaging.

Fractional flow reserve guided revascularization in daily practice: clinical judgment does not always meet science.

PubMed

Rubinshtein, Ronen; Jaffe, Ronen

2013-09-01

Measurement of the fractional flow reserve (FFR) during invasive coronary angiography is the accepted ''gold standard'' for assessing the functional significance of coronary artery lesions by determination of the characteristics of blood flow proximal and distal to a coronary stenosis during pharmacologically-mediated hyperemia. Abnormal FFR is associated with higher cardiac event rate if the coronary lesion is left untreated. On the other hand, it was shown that patients derived no clinical benefit from revascularization of angiographically obstructive lesions which were hemodynamically insignificant according to FFR (>0.8). This editorial comment refers to an observational cohort study which reported that in approximately 20% of real world patients the treatment strategy chosen was discordant with FFR findings. Our comment discusses these findings and concludes that while the standard of care is to treat patients in accordance with their FFR results (when available), it should be recognized that there are some clinical scenarios that may require a treatment strategy that is discordant with FFR result.

Drag reducing polymers improve coronary flow reserve through modulation of capillary resistance.

PubMed

Pacella, John J; Kameneva, Marina V; Villanueva, Flordeliza S

2009-01-01

We have shown that drag-reducing polymers (DRP) reduce microvascular resistance and improve myocardial perfusion during coronary stenosis. We used myocardial contrast echocardiography (MCE) and mathematical modeling to define the DRP microvascular effects. A non-flow-limiting left anterior descending (LAD) stenosis was created in 8 dogs. Intramyocardial blood volume, RBC velocity and flow in the LAD and circumflex (CX) beds were obtained from MCE at baseline, and in hyperemia, stenosis, hyperemia + stenosis, and hyperemia + stenosis + DRP. Microvascular resistances were calculated from a lumped-parameter model. During stenosis + hyperemia, LAD bed microvascular resistance increased (p<0.015), and capillary volume (p<0.002) and red cell velocity (p<0.0004) decreased relative to baseline. With DRP, during stenosis and hyperemia, LAD bed microvascular resistance decreased (p<0.04); there was an increase in capillary volume (p<0.007), RBC velocity (p<0.006), and flow (p<0.05). Decreased model-computed capillary resistance accounted for the reduction in LAD bed resistance after DRP. We conclude that DRP improve flow reserve during coronary stenosis by modulating capillary resistance. Primary modification of the rheological properties of blood to affect capillary resistance is a novel approach for the treatment of acute coronary syndromes.

Indirect carotid cavernous fistula mimicking ocular myasthenia.

PubMed

Leishangthem, Lakshmi; Satti, Sudhakar Reddy

2017-10-19

71-year-old woman with progressive left-sided, monocular diplopia and ptosis. Her symptoms mimicked ocular myasthenia, but she had an indirect carotid cavernous fistula (CCF). She was diagnosed with monocular myasthenia gravis (negative acetylcholinesterase antibody) after a positive ice test and started on Mestinon and underwent a thymectomy complicated by a brachial plexus injury. Months later, she developed left-sided proptosis and ocular bruit. She was urgently referred to neuro-interventional surgery and was diagnosed with an indirect high-flow left CCF, which was treated with Onyx liquid and platinum coil embolisation. Mestinon was discontinued. Her ophthalmic symptoms resolved. However, she was left with a residual left arm and hand hemiparesis and dysmetria secondary to a brachial plexus injury. Indirect CCF usually can present with subtle and progressive symptoms leading to delayed diagnosis or misdiagnosis. It is important for ophthalmologists to consider this differential in a patient with progressive ocular symptoms. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Prevalence, clinical and echocardiographic characteristics of various flow and gradient patterns in mild or moderate aortic stenosis with normal left ventricular ejection fraction.

PubMed

Tan, Yong-Qiang Benjamin; Ngiam, Jinghao Nicholas; Kong, William K F; Yeo, Tiong-Cheng; Poh, Kian-Keong

2016-10-15

Paradoxical low-flow aortic stenosis (AS) with preserved left ventricular ejection fraction (LVEF) has only been described in severe AS. Controversy surrounds prognosis and management but no studies have reported this phenomenon in mild or moderate AS. We investigated the prevalence of flow and gradient patterns in this population, characterising their clinical and echocardiographic profile. Consecutive subjects (n=1362) with isolated AS: mild (n=462, aortic valve area≥1.5cm(2), 2.5m/s

Left Atrial 4D Blood Flow Dynamics and Hemostasis following Electrical Cardioversion of Atrial Fibrillation.

PubMed

Cibis, Merih; Lindahl, Tomas L; Ebbers, Tino; Karlsson, Lars O; Carlhäll, Carl-Johan

2017-01-01

Background: Electrical cardioversion in patients with atrial fibrillation is followed by a transiently impaired atrial mechanical function, termed atrial stunning. During atrial stunning, a retained risk of left atrial thrombus formation exists, which may be attributed to abnormal left atrial blood flow patterns. 4D Flow cardiovascular magnetic resonance (CMR) enables blood flow assessment from the entire three-dimensional atrial volume throughout the cardiac cycle. We sought to investigate left atrial 4D blood flow patterns and hemostasis during left atrial stunning and after left atrial mechanical function was restored. Methods: 4D Flow and morphological CMR data as well as blood samples were collected in fourteen patients at two time-points: 2-3 h (Time-1) and 4 weeks (Time-2) following cardioversion. The volume of blood stasis and duration of blood stasis were calculated. In addition, hemostasis markers were analyzed. Results: From Time-1 to Time-2: Heart rate decreased (61 ± 7 vs. 56 ± 8 bpm, p = 0.01); Maximum change in left atrial volume increased (8 ± 4 vs. 22 ± 15%, p = 0.009); The duration of stasis (68 ± 11 vs. 57 ± 8%, p = 0.002) and the volume of stasis (14 ± 9 vs. 9 ± 7%, p = 0.04) decreased; Thrombin-antithrombin complex (TAT) decreased (5.2 ± 3.3 vs. 3.3 ± 2.2 μg/L, p = 0.008). A significant correlation was found between TAT and the volume of stasis ( r 2 = 0.69, p < 0.001) at Time-1 and between TAT and the duration of stasis ( r 2 = 0.34, p = 0.04) at Time-2. Conclusion: In this longitudinal study, left atrial multidimensional blood flow was altered and blood stasis was elevated during left atrial stunning compared to the restored left atrial mechanical function. The coagulability of blood was also elevated during atrial stunning. The association between blood stasis and hypercoagulability proposes that assessment of left atrial 4D flow can add to the pathophysiological understanding of thrombus formation during atrial fibrillation related atrial stunning.

Preferential cephalic redistribution of left ventricular cardiac output during therapeutic hypothermia for perinatal hypoxic-ischemic encephalopathy.

PubMed

Hochwald, Ori; Jabr, Mohammad; Osiovich, Horacio; Miller, Steven P; McNamara, Patrick J; Lavoie, Pascal M

2014-05-01

To determine the relationship between left ventricular cardiac output (LVCO), superior vena cava (SVC) flow, and brain injury during whole-body therapeutic hypothermia. Sixteen newborns with moderate or severe hypoxic-ischemic encephalopathy were studied using echocardiography during and immediately after therapeutic hypothermia. Measures were also compared with 12 healthy newborns of similar postnatal age. Newborns undergoing therapeutic hypothermia also had cerebral magnetic resonance imaging as part of routine clinical care on postnatal day 3-4. LVCO was markedly reduced (mean ± SD 126 ± 38 mL/kg/min) during therapeutic hypothermia, whereas SVC flow was maintained within expected normal values (88 ± 27 mL/kg/min) such that SVC flow represented 70% of the LVCO. The reduction in LVCO during therapeutic hypothermia was mainly accounted by a reduction in heart rate (99 ± 13 vs 123 ± 17 beats/min; P < .001) compared with immediately postwarming in the context of myocardial dysfunction. Neonates with brain injury on magnetic resonance imaging had higher SVC flow prerewarming, compared with newborns without brain injury (P = .013). Newborns with perinatal hypoxic-ischemic encephalopathy showed a preferential systemic-to-cerebral redistribution of cardiac blood flow during whole-body therapeutic hypothermia, which may reflect a lack of cerebral vascular adaptation in newborns with more severe brain injury. Copyright © 2014 Elsevier Inc. All rights reserved.

Crossed aphasia following an infarction in the right corpus callosum.

PubMed

Ishizaki, Masatoshi; Ueyama, Hidetsugu; Nishida, Yasuto; Imamura, Shigehiro; Hirano, Teruyuki; Uchino, Makoto

2012-02-01

A 68-year-old right-handed woman with no history of brain damage or familial left-handedness was admitted to our hospital due to the acute onset of speech difficulty; her speech was nonfluent. Literal and phonological paraphasias, agrammatism and paragrammatism were observed. Brain MRI revealed an acute infarction in the right anterior cerebral artery territory, involving the right corpus callosum. Moreover, cerebral blood flow was decreased not only in the area of the right corpus callosum but also in the left fronto-temporal lobe, suggesting crossed diaschisis. This is a rare case of crossed aphasia following an infarction in the right corpus callosum. Copyright © 2011 Elsevier B.V. All rights reserved.

An endovascular option is the final treatment for a giant arteriovenous malformation.

PubMed

Benedetto, Filippo; Pipitò, Narayana; Barillà, David; Spinelli, Domenico; Stilo, Francesco; Spinelli, Francesco

2014-11-01

We report the case of a 58-year-old man presented with bleeding ulcer of the left arm caused by a high-flow type-C arteriovenous malformation (AVM), feed by branches from both the subclavian arteries. He had been previously treated with AVM sclerotherapy, embolization, humeral artery endografting, and open surgery. We urgently performed coil embolization of the left vertebral artery, and we covered the huge subclavian artery by a thoracic endograft. Then, we embolized the right tyrocervical trunk. The result was an immediate interruption of bleeding. At 12 months, the patient had no neurologic complications, and the upper limb continued to decompress. Copyright © 2014 Elsevier Inc. All rights reserved.

Relative Renal Blood Flow Measurements With Rb-82 and a Hybrid Gamma Camera Using a Pig Model

NASA Astrophysics Data System (ADS)

Pretorius, P. H.; Fung, L. C. T.; Schell, C. P.; King, M. A.

2005-02-01

We have successfully demonstrated with chronically implanted blood flow probes in a pig model that renal uptake of Rb-82 is indeed sensitive to acute renal blood flow changes. Two flow probes were placed around the left and right renal arteries in a surgical procedure nine weeks before the first Rb-82 measurements. Together with the flow probes, a flow restrictor was implanted around the left renal artery. Single bolus infusions of 6 mCi Rb-82 were used to study the uptake in the kidneys approximately 7 minutes apart in hybrid-image limited-angle acquisitions (stationary camera heads posterior and anterior of the pig) while changing the flow to the left kidney between acquisitions. The acquired data were reconstructed into 7.5-s frames using a maximum likelihood (ML) list-mode reconstruction algorithm exploiting timing signals inserted into the list every 0.25 s. Reconstructed data were orientated to coronal views before regions of interest (ROIs) were drawn over both kidneys with a separate background region for each. The data represented are noisy due to the reconstructed 7.5-s frames, and the total imaging time of 5 min (or 4 Rb-82 half-lives). We were able to show a steady decline in uptake of Rb-82 in the left kidney that correlates with the reduction in renal blood flow. The reduced blood flow to the left kidney affects the Rb-82 uptake to the right kidney slightly, while blood flow decreased up to 33%. Comparing the baseline renal blood flow of the left kidney obtained before and after the intervention indicates that some ischemia persists after blood flow was restored. Attenuation compensation better described the contour of the kidney but only scales the time activity curve without changing its shape.

Relationship between parietal blood flow studies in the left colon and the rectum in dogs. Colonic pressure and blood flow.

PubMed

Arhan, P; Bouchoucha, M; Martelli, H; Rimbert, J N; Berdeaux, A; Gallix, P; Héro, M; Barritault, L; Pellerin, D; Devroede, G

1988-01-01

An animal model was proposed to clarify the difference in occurrence of enterocolitis in congenital aganglionosis. When gaseous distention of the colon was localized to the rectosigmoid area, enterocolitis never occurred. On the contrary, when it involved the left colon, enterocolitis occurred in 13 of 15 patients. Intestinal blood flow rates were simultaneously measured in the left colon and rectum of six dogs by using labeled microspheres and expressed in function of the intraluminal pressure. Results show that for elevated values of intraluminal pressure, blood flow was significantly lower in the left colon than in the rectum. These results may explain why ischemia and necrosis occurred more frequently in the left colon than in the rectum.

A Case of Left Renal Vein Ligation in a Patient with Solitary Left Kidney Undergoing Liver Transplantation to Control Splenorenal Shunt and Improve Portal Venous Flow.

PubMed

Martino, Rodrigo B; Júnior, Eserval Rocha; Manuel, Valdano; Rocha-Santos, Vinicius; D'Albuquerque, Luis Augusto C; Andraus, Wellington

2017-10-11

BACKGROUND Adequate portal venous flow is required for successful liver transplantation. Reduced venous flow and blood flow 'steal' by collateral vessels are a concern, and when there is a prominent splenorenal shunt present, ligation of the left renal vein has been recommended to improve portal venous blood flow. CASE REPORT A 51-year-old man who had undergone right nephrectomy in childhood required liver transplantation for liver cirrhosis and hepatocellular carcinoma due to hepatitis C virus (HCV) infection. The patient had no other comorbidity and no history of hepatorenal syndrome. At transplantation surgery, portal venous flow was poor and did not improve with ligation of shunt veins, but ligation of the left renal vein improved portal venous flow. On the first and fifth postoperative days, the patient was treated with basiliximab, a chimeric monoclonal antibody to the IL-2 receptor, and methylprednisolone. The calcineurin inhibitor, tacrolimus, was introduced on the fifth postoperative day. On the sixteenth postoperative day, renal color Doppler ultrasound showed normal left renal parenchyma; hepatic Doppler ultrasound showed good portal vein flow and preserved hepatic parenchyma in the liver transplant. CONCLUSIONS This case report has shown that in a patient with a single left kidney, left renal vein ligation is feasible and safe in a patient with no other risk factors for renal impairment following liver transplantation. Modification of postoperative immunosuppression to avoid calcineurin inhibitors in the very early postoperative phase may be important in promoting good recovery of renal function and to avoid the need for postoperative renal dialysis.

Physical limits of flow sensing in the left-right organizer

PubMed Central

Ferreira, Rita R; Vilfan, Andrej; Jülicher, Frank; Supatto, Willy; Vermot, Julien

2017-01-01

Fluid flows generated by motile cilia are guiding the establishment of the left-right asymmetry of the body in the vertebrate left-right organizer. Competing hypotheses have been proposed: the direction of flow is sensed either through mechanosensation, or via the detection of chemical signals transported in the flow. We investigated the physical limits of flow detection to clarify which mechanisms could be reliably used for symmetry breaking. We integrated parameters describing cilia distribution and orientation obtained in vivo in zebrafish into a multiscale physical study of flow generation and detection. Our results show that the number of immotile cilia is too small to ensure robust left and right determination by mechanosensing, given the large spatial variability of the flow. However, motile cilia could sense their own motion by a yet unknown mechanism. Finally, transport of chemical signals by the flow can provide a simple and reliable mechanism of asymmetry establishment. DOI: http://dx.doi.org/10.7554/eLife.25078.001 PMID:28613157

Continuous-Flow Left Ventricular Assist Device Support Improves Myocardial Supply:Demand in Chronic Heart Failure.

PubMed

Soucy, Kevin G; Bartoli, Carlo R; Phillips, Dustin; Giridharan, Guruprasad A; Sobieski, Michael A; Wead, William B; Dowling, Robert D; Wu, Zhongjun J; Prabhu, Sumanth D; Slaughter, Mark S; Koenig, Steven C

2017-06-01

Continuous-flow left ventricular assist devices (CF LVADs) are rotary blood pumps that improve mean blood flow, but with potential limitations of non-physiological ventricular volume unloading and diminished vascular pulsatility. In this study, we tested the hypothesis that left ventricular unloading with increasing CF LVAD flow increases myocardial flow normalized to left ventricular work. Healthy (n = 8) and chronic ischemic heart failure (IHF, n = 7) calves were implanted with CF LVADs. Acute hemodynamics and regional myocardial blood flow were measured during baseline (LVAD off, clamped), partial (2-4 L/min) and full (>4 L/min) LVAD support. IHF calves demonstrated greater reduction of cardiac energy demand with increasing LVAD support compared to healthy calves, as calculated by rate-pressure product. Coronary artery flows (p < 0.05) and myocardial blood flow (left ventricle (LV) epicardium and myocardium, p < 0.05) decreased with increasing LVAD support in normal calves. In the IHF model, blood flow to the septum, LV, LV epicardium, and LV myocardium increased significantly with increasing LVAD support when normalized to cardiac energy demand (p < 0.05). In conclusion, myocardial blood flow relative to cardiac demand significantly increased in IHF calves, thereby demonstrating that CF LVAD unloading effectively improves cardiac supply and demand ratio in the setting of ischemic heart failure.

N-terminal pro-brain natriuretic peptide is related with coronary flow velocity reserve and diastolic dysfunction in patients with asymmetric hypertrophic cardiomyopathy.

PubMed

Tesic, Milorad; Seferovic, Jelena; Trifunovic, Danijela; Djordjevic-Dikic, Ana; Giga, Vojislav; Jovanovic, Ivana; Petrovic, Olga; Marinkovic, Jelena; Stankovic, Sanja; Stepanovic, Jelena; Ristic, Arsen; Petrovic, Milan; Mujovic, Nebojsa; Vujisic-Tesic, Bosiljka; Beleslin, Branko; Vukcevic, Vladan; Stankovic, Goran; Seferovic, Petar

2017-10-01

The relations of elevated N-terminal pro-brain natriuretic peptide (NT-pro-BNP) and cardiac ischemia in hypertrophic cardiomyopathy (HCM) patients is uncertain. Therefore we designed the study with the following aims: (1) to analyze plasma concentrations of NT-pro-BNP in various subsets of HCM patients; (2) to reveal the correlations of NT-pro-BNP, myocardial ischemia, and diastolic dysfunction; (3) to assess predictors of the elevated plasma levels of NT-pro-BNP. In 61 patients (mean age 48.9±16.3 years; 26 male) with asymmetric HCM plasma levels of NT-pro-BNP were obtained. Standard transthoracic examination, tissue Doppler echocardiography with measurement of transthoracic coronary flow velocity reserve (CFVR) in left anterior descending artery (LAD) was done. Mean natural logarithm value of NT-pro-BNP was 7.11±0.95pg/ml [median value 1133 (interquartile range 561-2442)pg/ml]. NT-pro-BNP was significantly higher in patients with higher NYHA class, in obstructive HCM, more severe mitral regurgitation, increased left atrial volume index (LAVI), presence of calcified mitral annulus, elevated left ventricular (LV) filling pressure and in decreased CFVR. Levels of NT-pro-BNP significantly correlated with the ratio of E/e' (r=0.534, p<0.001), LV outflow tract gradient (r=0.503, p=0.024), LAVI (r=0.443, p<0.001), while inversely correlated with CFVR LAD (r=-0.569, p<0.001). When multivariate analysis was done only CFVR LAD and E/e' emerged as independent predictors of NT-pro-BNP. Plasma levels of NT-pro-BNP were significantly higher in HCM patients with more advanced disease. Elevated NT-pro-BNP not only reflects the diastolic impairment of the LV, but it might also be the result of cardiac ischemia in patients with HCM. Copyright © 2017 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.

Effects of milk flow on the physiological and behavioural responses to feeding in an infant with hypoplastic left heart syndrome.

PubMed

Pados, Britt F; Thoyre, Suzanne M; Estrem, Hayley H; Park, Jinhee; Knafl, George J; Nix, Brant

2017-01-01

Infants with hypoplastic left heart syndrome often experience difficulty with oral feeding, which contributes to growth failure, morbidity, and mortality. In response to feeding difficulty, clinicians often change the bottle nipple, and thus milk flow rate. Slow-flow nipples have been found to reduce the stress of feeding in other fragile infants, but no research has evaluated the responses of infants with hypoplastic left heart syndrome to alterations in milk flow. The purpose of this study was to evaluate the physiological and behavioural responses of an infant with hypoplastic left heart syndrome to bottle feeding with either a slow-flow (Dr. Brown's Preemie) or a standard-flow (Dr. Brown's Level 2) nipple. A single infant was studied for three feedings: two slow-flow and one standard-flow. Oral feeding, whether with a slow-flow or a standard-flow nipple, was distressing for this infant. During slow-flow feeding, she experienced more coughing events, whereas during standard-flow she experienced more gagging. Disengagement and compelling disorganisation were most common during feeding 3, that is slow-flow, which occurred 2 days after surgical placement of a gastrostomy tube. Clinically significant changes in heart rate, oxygen saturation, and respiratory rate were seen during all feedings. Heart rate was higher during standard-flow and respiratory rate was higher during slow-flow. Further research is needed to examine the responses of infants with hypoplastic left heart syndrome to oral feeding and to identify strategies that will support these fragile infants as they learn to feed. Future research should evaluate an even slower-flow nipple along with additional supportive feeding strategies.

Energy efficiency and pulmonary artery flow after balloon pulmonary angioplasty for inoperable, chronic thromboembolic pulmonary hypertension: Analysis by phase-contrast MRI.

PubMed

Nagao, Michinobu; Yamasaki, Yuzo; Abe, Kohtaro; Hosokawa, Kazuya; Kawanami, Satoshi; Kamitani, Takeshi; Yamanouchi, Torahiko; Yabuuchi, Hidetake; Fukushima, Kenji; Honda, Hiroshi

2017-02-01

The aims of this study were to propose a new quantitative method for pulmonary artery (PA) flow energetics using phase-contrast magnetic resonance imaging (PC-MRI), and to investigate how balloon pulmonary angioplasty (BPA) impacts energetics in chronic thromboembolic pulmonary hypertension (CTEPH). PC-MRI at 3-Teslar and with a flow sensitive gradient echo was used to examine energetics prior to and following BPA for 24 CTEPH patients. Stroke volume (m; ml) and mean velocity (V; mm/s) for the main pulmonary artery (PA), right PA, and left PA were calculated from a time-flow curve derived from PC-MRI. Based on the Bernoulli principle, PA energy was identified as 1/2mV 2 (μj/kg), and energy loss was defined as the following equation "energy loss=main PA energy-(rt. PA energy+lt. PA energy)". Right PA energy was significantly greater post-BPA than pre-BPA (61±55 vs. 32±40μj/kg). There was no difference in main PA and left PA energies. Energy loss was significantly decreased post-BPA (18±97μj/kg) than pre-BPA (79±125μj/kg). An optimal cutoff of left PA energy of 45μj/kg pre-BPA can be used to predict patients with mPAP≥30mmHg after BPA, with an area under the curve of 0.91, 78% sensitivity, and 92% specificity. Analysis of PA energetics using phase-contrast MRI demonstrates that BPA improves energy loss in CTEPH. In addition, BPA responses can be predicted by PA energy status pre-treatment. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Angina Relief by Ranolazine Identifies False-Negative SPECT Myocardial Perfusion Scans in Patients with Coronary Disease Demonstrated by Coronary Angiography.

PubMed

Murray, Gary L

2014-09-01

Normal myocardial perfusion imaging (MPI) reduces intermediate- or high-risk pretest probability patients to low- or intermediate-risk posttest probability, respectively, for coronary disease (CD). Since ranolazine (RAN) relieves only angina, anginal patients with normal MPI whose angina is relieved by RAN present a significant dilemma. The purpose of this retrospective chart review was to confirm the impression that coronary angiography (CA) is indicated in patients whose class 3 to 4 angina is relieved by RAN, but have normal myocardial single-photon emission computed tomography (SPECT) MPIs. Charts of patients with stable class 3 to 4 angina (typical and atypical) and normal MPIs (left ventricular ejection fraction [LVEF] ≥50% and segmental score = 0) were reviewed. CA was done on all the patients with complete angina relief taking RAN, as well as nonresponders whose anginal etiology could not be explained. Stenoses were considered flow-restrictive when more than 70% diameter stenosis is observed by quantitative CA, or, when 50 to 70%, fractional flow reserve (FFR) measured ≤0.80. RAN relieved angina in 36 of 54 (67%) patients. Of the known cases, 25 of these 36 (69%) had 43 stenoses ≥50% (mean = 66%): 15 (60%) had 1 vessel disease; 9 (36%) had multivessel disease; 18 (72%) had left anterior descending (LAD) disease; 1 (4%) had left main disease. Twenty one of 43 (49%) stenosis were > 70%; 22 (51%) stenoses were 50 to 70% and required FFR measurement. Twenty nine of 43 stenoses (67%) were considered flow-restrictive in 18 of these 25 (72%) patients. Eight RAN nonresponders with no explanation for angina had no CD at CA. RAN angina relief is invaluable in identifying falsely negative SPECT MPI, and 50% of these patients have flow-restrictive stenoses.

In vivo quantification of intraventricular flow during left ventricular assist device support

NASA Astrophysics Data System (ADS)

Vu, Vi; Wong, Kin; Del Alamo, Juan; Aguilo, Pablo M. L.; May-Newman, Karen; Department of Bioengineering, San Diego State University Collaboration; Department of Mechanical; Aerospace Engineering, University of California San Diego Collaboration; Mechanical Assist Device Program, Sharp Memorial Hospital Collaboration

2014-11-01

Left ventricular assist devices (LVADs) are mechanical pumps that are surgically connected to the left ventricle (LV) and aorta to increase aortic flow and end-organ perfusion. Clinical studies have demonstrated that LVADs improve patient health and quality of life and significantly reduce the mortality of cardiac failure. However, In the presence of left ventricular assisted devices (LVAD), abnormal flow patterns and stagnation regions are often linked to thrombosis. The aim of our study is to evaluate the flow patterns in the left ventricle of the LVAD-assisted heart, with a focus on alterations in vortex development and blood stasis. To this aim, we applied color Doppler echocardiography to measure 2D, time resolved velocity fields in patients before and after implantation of LVADs. In agreement with our previous in vitro studies (Wong et al., Journal of Biomechanics 47, 2014), LVAD implantation resulted in decreased flow velocities and increased blood residence time near the outflow tract. The variation of residence time changes with LVAD operational speed was characterized for each patient.

Influence of anatomical dominance and hypertension on coronary conduit arterial and microcirculatory flow patterns: a multiscale modeling study.

PubMed

Mynard, Jonathan P; Smolich, Joseph J

2016-07-01

Coronary hemodynamics are known to be affected by intravascular and extravascular factors that vary regionally and transmurally between the perfusion territories of left and right coronary arteries. However, despite clinical evidence that left coronary arterial dominance portends greater cardiovascular risk, relatively little is known about the effects of left or right dominance on regional conduit arterial and microcirculatory blood flow patterns, particularly in the presence of systemic or pulmonary hypertension. We addressed this issue using a multiscale numerical model of the human coronary circulation situated in a closed-loop cardiovascular model. The coronary model represented left or right dominant anatomies and accounted for transmural and regional differences in vascular properties and extravascular compression. Regional coronary flow dynamics of the two anatomical variants were compared under normotensive conditions, raised systemic or pulmonary pressures with maintained flow demand, and after accounting for adaptations known to occur in acute and chronic hypertensive states. Key findings were that 1) right coronary arterial flow patterns were strongly influenced by dominance and systemic/pulmonary hypertension; 2) dominance had minor effects on left coronary arterial and all microvascular flow patterns (aside from mean circumflex flow); 3) although systemic hypertension favorably increased perfusion pressure, this benefit varied regionally and transmurally and was offset by increased left ventricular and septal flow demands; and 4) pulmonary hypertension had a substantial negative effect on right ventricular and septal flows, which was exacerbated by greater metabolic demands. These findings highlight the importance of interactions between coronary arterial dominance and hypertension in modulating coronary hemodynamics. Copyright © 2016 the American Physiological Society.

The effects of hypoxemia on myocardial blood flow during exercise.

PubMed

Paridon, S M; Bricker, J T; Dreyer, W J; Reardon, M; Smith, E O; Porter, C B; Michael, L; Fisher, D J

1989-03-01

We evaluated the adequacy of regional and transmural blood flow during exercise and rapid pacing after 1 wk of hypoxemia. Seven mature mongrel dogs were made hypoxemic (mean O2 saturation = 72.4%) by anastomosis of left pulmonary artery to left atrial appendage. Catheters were placed in the left atrium, right atrium, pulmonary artery, and aorta. Atrial and ventricular pacing wires were placed. An aortic flow probe was placed to measure cardiac output. Ten nonshunted dogs, similarly instrumented, served as controls. Recovery time was approximately 1 wk. Cardiac output, mean aortic pressure, and oxygen saturation were measured at rest, with ventricular pacing, atrial pacing, and with treadmill exercise. Ventricular and atrial pace and exercise were at a heart rate of 200. Right ventricular free wall, left ventricular free wall, and septal blood flow were measured with radionuclide-labeled microspheres. Cardiac output, left atrial blood pressure, and aortic blood pressure were similar between the two groups of dogs in all testing states. Myocardial blood flow was significantly higher in the right and left ventricular free wall in the hypoxemic animals during resting and exercise testing states. Myocardial oxygen delivery was similar between the two groups of animals. Pacing resulted in an increase in myocardial blood flow in the control animals but not the hypoxemic animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Vector flow mapping in obstructive hypertrophic cardiomyopathy to assess the relationship of early systolic left ventricular flow and the mitral valve.

PubMed

Ro, Richard; Halpern, Dan; Sahn, David J; Homel, Peter; Arabadjian, Milla; Lopresto, Charles; Sherrid, Mark V

2014-11-11

The hydrodynamic cause of systolic anterior motion of the mitral valve (SAM) is unresolved. This study hypothesized that echocardiographic vector flow mapping, a new echocardiographic technique, would provide insights into the cause of early SAM in obstructive hypertrophic cardiomyopathy (HCM). We analyzed the spatial relationship of left ventricular (LV) flow and the mitral valve leaflets (MVL) on 3-chamber vector flow mapping frames, and performed mitral valve measurements on 2-dimensional frames in patients with obstructive and nonobstructive HCM and in normal patients. We compared 82 patients (22 obstructive HCM, 23 nonobstructive HCM, and 37 normal) by measuring 164 LV pre- and post-SAM velocity vector flow maps, 82 maximum isovolumic vortices, and 328 2-dimensional frames. We observed color flow and velocity vector flow posterior to the MVL impacting them in the early systolic frames of 95% of obstructive HCM, 22% of nonobstructive HCM, and 11% of normal patients (p < 0.001). In both pre- and post-SAM frames, we measured a high angle of attack >60° of local vector flow onto the posterior surface of the leaflets whether the flow was ejection (59%) or the early systolic isovolumic vortex (41%). Ricochet of vector flow, rebounding off the leaflet into the cul-de-sac, was noted in 82% of the obstructed HCM, 9% of nonobstructive HCM, and none (0%) of the control patients (p < 0.001). Flow velocities in the LV outflow tract on the pre-SAM frame 1 and 2 mm from the tip of the anterior leaflet were low: 39 and 43 cm/s, respectively. Early systolic flow impacts the posterior surfaces of protruding MVL initiating SAM in obstructive HCM. Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Assessment of internal mammary artery and saphenous vein graft patency and flow reserve using transthoracic Doppler echocardiography

NASA Technical Reports Server (NTRS)

Chirillo, F.; Bruni, A.; Balestra, G.; Cavallini, C.; Olivari, Z.; Thomas, J. D.; Stritoni, P.

2001-01-01

OBJECTIVE: To investigate transthoracic Doppler echocardiography in the identification of coronary artery bypass graft (CABG) flow for assessing graft patency. DESIGN: The initial study group comprised 45 consecutive patients with previous CABG undergoing elective cardiac catheterisation for recurrent ischaemia. The Doppler variables best correlated with angiographic graft patency were then tested prospectively in a further 84 patients (test group). SETTING: Three tertiary referral centres. INTERVENTIONS: Flow velocities in grafts were recorded at rest and during hyperaemia induced by dipyridamole (0.56 mg/kg/4 min), under the guidance of transthoracic colour Doppler flow mapping. Findings on transthoracic Doppler were compared with angiography. MAIN OUTCOME MEASURES: Feasibility of identifying open grafts by Doppler and diagnostic accuracy for Doppler detection of significant (>/= 70%) graft stenosis. RESULTS: In the test group the identification rate for mammary artery grafts was 100%, for saphenous vein grafts to left anterior descending coronary artery 91%, for vein grafts to right coronary artery 96%, and for vein grafts to circumflex artery 90%. Coronary flow reserve (the ratio between peak diastolic velocity under hyperaemia and at baseline) of < 1.9 (95% confidence interval 1.83 to 2.08) had 100% sensitivity, 98% specificity, 87.5% positive predictive value, and 100% negative predictive value for mammary artery graft stenosis. Coronary flow reserve of < 1.6 (95% CI 1.51 to 1.73) had 91% sensitivity, 87% specificity, 85.4% positive predictive value, and 92.3% negative predictive value for significant vein graft stenosis. CONCLUSIONS: Transthoracic Doppler can provide non-invasive assessment of CABG patency.

Standardization of the two-dimensional transcoelomic echocardiographic examination in the central bearded dragon (Pogona vitticeps).

PubMed

Silverman, S; Sanchez-Migallon Guzman, D; Stern, J; Gustavsen, K A; Griffiths, L G

2016-06-01

To objectively and subjectively describe the normal spectrum of two-dimensional echocardiographic findings in the central bearded dragon (Pogona vitticeps). Sixteen central bearded dragons. Central bearded dragons were prospectively evaluated under manual restraint in right and left lateral recumbency to identify imaging planes for reproducible measurements of cardiac chambers, subjective two-dimensional analysis and color Doppler assessment. Echocardiography can be performed through windows in the left and right axillae. The window in the left axilla allows for a subjective and objective assessment of cardiac structure and function. The right axillary window allows for evaluation of pulmonary artery flow. Both views provide data for the presence of pericardial effusion or valvular insufficiency. With optimized imaging planes, cardiac chambers and fractional area change along with fractional shortening in the longitudinal and transverse planes can be calculated. Body weight and cardiac chamber dimensions of males were significantly larger than females. Ventricular fractional area change was the most consistent functional assessment. The majority of animals were found to have no evidence of valvular insufficiency, while approximately half had evidence of pericardial fluid. Pulmonary artery flow was assessed in all patients. Left and right aortic velocities cannot be reliably obtained. This study is the first to generate reference values for cardiac structure and function in clinically healthy central bearded dragons. Valvular insufficiency is not a normal finding in central bearded dragons, while mild pericardial effusion may be. Copyright © 2015 Elsevier B.V. All rights reserved.

Test-Retest Repeatability of Myocardial Blood Flow Measurements using Rubidium-82 Positron Emission Tomography

NASA Astrophysics Data System (ADS)

Efseaff, Matthew

Rubidium-82 positron emission tomography (PET) imaging has been proposed for routine myocardial blood flow (MBF) quantification. Few studies have investigated the test-retest repeatability of this method. Same-day repeatability of rest MBF imaging was optimized with a highly automated analysis program using image-derived input functions and a dual spillover correction (SOC). The effects of heterogeneous tracer infusion profiles and subject hemodynamics on test-retest repeatability were investigated at rest and during hyperemic stress. Factors affecting rest MBF repeatability included gender, suspected coronary artery disease, and dual SOC (p < 0.001). The best repeatability coefficient for same-day rest MBF was 0.20 mL/min/g using a six-minute scan-time, iterative reconstruction, dual SOC, resting rate-pressure-product (RPP) adjustment, and a left atrium image-derived input function. The serial study repeatabilities of the optimized protocol in subjects with homogeneous RPPs and tracer infusion profiles was 0.19 and 0.53 mL/min/g at rest and stress, and 0.95 for stress / rest myocardial flow reserve (MFR). Subjects with heterogeneous tracer infusion profiles and hemodynamic conditions had significantly less repeatable MBF measurements at rest, stress, and stress/rest flow reserve (p < 0.05).

Detection of intracardiac shunt flow in atrial septal defect using a real-time two-dimensional color-coded Doppler flow imaging system and comparison with contrast two-dimensional echocardiography.

PubMed

Suzuki, Y; Kambara, H; Kadota, K; Tamaki, S; Yamazato, A; Nohara, R; Osakada, G; Kawai, C

1985-08-01

To evaluate the noninvasive detection of shunt flow using a newly developed real-time 2-dimensional color-coded Doppler flow imaging system (D-2DE), 20 patients were examined, including 10 with secundum atrial septal defect (ASD) and 10 control subjects. These results were compared with contrast 2-dimensional echocardiography (C-2DE). Doppler 2DE displayed the blood flow toward the transducer as red and the blood flow away from the transducer as blue in 8 shades, each shade adding green according to the degree of variance in Doppler frequency. In the patients with ASD, D-2DE clearly visualized left-to-right shunt flow in 7 of 10 patients. In 5 of these 7 patients, C-2DE showed a negative contrast effect in the same area of the right atrium. Thus, D-2DE increased the sensitivity over C-2DE for detecting left-to-right shunt flow (from 50% to 70%). However, the specificity was slightly less in D-2DE (90%) than C-2DE (100%). Doppler 2DE could not visualize right-to-left shunt flow in all patients with ASD, though C-2DE showed a positive contrast effect in the left-sided heart in 9 of 10 patients with ASD. Thus, D-2DE is clinically useful for detecting left-to-right shunt flow in patients with ASD.

[Transcient ischemic attack, a rare manifestation of Eagle syndrome].

PubMed

Usseglio, J; Montoro, F Macian; Martin, S; Lerat, J; Laloze, J; Taibi, A; Brie, J

2016-12-01

Clinical presentation of Eagle syndrome (ES) is very variable and non-specific, making its diagnosis difficult. It is usually limited to pain. Transient neurological manifestations are exceptional. We report one case in which the diagnosis of ES has been made based on neurological events occurring during left anterolateral head bending, without pain. A 47-year-old man presented with transient neurological events progressing since two years, half-right body paresthesia and reduced field of vision on the left side type, triggered by left anterolateral head flexion and regressive in neutral position. Transcranial Doppler and CT angiography of the supra-aortic trunks were performed in neutral position and in right and left head rotation that showed a disruption of the left sylvian flow and an extrinsic compression of the left internal carotid artery, due to a musculoskeletal impediment involving the lower end of the temporal styloid process. Complete recovering was achieved after surgical resection of this process. A control CT angiography confirmed the cessation of the compression. ES has non-specific and highly variable clinical manifestations making diagnosis difficult or leading to misdiagnosis. ES should be considered in any transient neurological deficit, especially when occurring during head rotation. Treatment relies on surgical resection of the excessively long styloid process. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Asymptomatic young man with an incidental murmur.

PubMed

Shojaeifard, Maryam; Pouraliakbar, Hamid Reza; Houshmand, Golnaz

2018-05-31

A 32-year old man was referred to our institution for transthoracic echocardiography (TTE) following detection of an incidental murmur on physical examination before blood donation. He was asymptomatic with no significant medical history. Physical examination revealed dual heart sounds with a grade II/VI systolic murmur heard in the left sternal border. An ECG was in normal sinus rhythm. TTE was performed (figure 1A-C, online supplementary videos 1-4) followed by cardiac CT angiography (CTA) (figure 1D,E).heartjnl;heartjnl-2018-313223v1/F1F1F1Figure 1(A) Transthoracic echocardiography, parasternal left ventricular long axis view. (B) Colour Doppler of modified short axis in the mid-left ventricular level. (C) Doppler flow velocity profile. (D) Cardiac CT angiography (CTA) sagittal reconstruction. (E) Three-dimensional CTA reconstruction of the heart. What is the diagnosis?Pericardial cyst.Ventricular septal defect.Kawasaki.Anomalous left coronary artery from pulmonary artery (ALCAPA). © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Effect of diastolic flow patterns on the function of the left ventricle

NASA Astrophysics Data System (ADS)

Seo, Jung Hee; Mittal, Rajat

2013-11-01

Direct numerical simulations are used to study the effect of intraventricular flow patterns on the pumping efficiency and the blood mixing and transport characteristics of the left ventricle. The simulations employ a geometric model of the left ventricle which is derived from contrast computed tomography. A variety of diastolic flow conditions are generated for a fixed ejection fraction in order to delineate the effect of flow patterns on ventricular performance. The simulations indicate that the effect of intraventricular blood flow pattern on the pumping power is physiologically insignificant. However, diastolic flow patterns have a noticeable effect on the blood mixing as well as the residence time of blood cells in the ventricle. The implications of these findings on ventricular function are discussed.

Relationship between residual blood flow in the infarct-related artery and scintigraphic infarct size, myocardial salvage, and functional recovery in patients with acute myocardial infarction.

PubMed

Ndrepepa, Gjin; Kastrati, Adnan; Schwaiger, Markus; Mehilli, Julinda; Markwardt, Christina; Dibra, Alban; Dirschinger, Josef; Schömig, Albert

2005-11-01

In patients with acute myocardial infarction (AMI) before primary coronary stenting with adjunct glycoprotein IIb/IIIa receptor blockade, whether residual blood flow in the infarct-related artery (IRA) affects infarct size or myocardial salvage is not known. This study included 118 patients with ST-segment elevation AMI who received coronary stenting plus abciximab. SPECT studies were performed before and 7-14 d after stenting. Patients were divided into a group with initial Thrombolysis in Myocardial Infarction (TIMI) flow grade < or = 1 (77 patients) and a group with initial TIMI flow grade > 1 (41 patients). The initial median perfusion defect and (in brackets) the 25th and 75th percentiles were 29.1% [21.0%; 52.0%] of the left ventricle in patients with TIMI flow grade < or = 1, versus 16.5% [8.0%; 33.1%] of the left ventricle in patients with TIMI flow grade > 1 (P < 0.001). Baseline left ventricular ejection fraction (54.0% [45.0; 63.0] vs. 57.0% [40.0; 62.0], P = 0.623) or extension of hypokinetic region (28.0 [14.0; 41.0] hypokinetic chords vs. 24.0 [13.0; 39.0] hypokinetic chords, P = 0.643) did not differ significantly between the group with TIMI flow grade < or = 1 and the group with TIMI flow grade > 1. Final infarct size was 11.0% [6.1%; 23.5%] of the left ventricle in the group with TIMI flow grade < = 1, versus 6.0% [2.0%; 12.8%] of the left ventricle in the group with TIMI flow > 1 (P = 0.008). Salvage index was 0.58 [0.38; 0.76] in the group with TIMI flow grade < or = 1, versus 0.61 [0.36; 0.74] in the group with TIMI flow grade > 1 (P = 0.952). At the day 14 angiography, patients with TIMI flow grade > 1 had better left ventricular ejection fraction (61.0% [54.0%; 68.0%] vs. 56.5% [42.9%; 65.0%]; P = 0.03) and a smaller hypokinetic region (7 chords [0; 22.0] vs. 16 chords [2.5; 30.0]; P = 0.024) than did patients with TIMI flow grade < or = 1. Preserved blood flow in the IRA in patients with AMI is associated with a smaller area at risk, a smaller infarct, and better recovery of regional and global left ventricular function. The proportion of initial area at risk salvaged by coronary stenting does not seem to depend on residual blood flow in the IRA.

Body position and activity, but not heart rate, affect pump flows in patients with continuous-flow left ventricular assist devices.

PubMed

Muthiah, Kavitha; Gupta, Sunil; Otton, James; Robson, Desiree; Walker, Robyn; Tay, Andre; Macdonald, Peter; Keogh, Anne; Kotlyar, Eugene; Granger, Emily; Dhital, Kumud; Spratt, Phillip; Jansz, Paul; Hayward, Christopher S

2014-08-01

The aim of this study was to determine the contribution of pre-load and heart rate to pump flow in patients implanted with continuous-flow left ventricular assist devices (cfLVADs). Although it is known that cfLVAD pump flow increases with exercise, it is unclear if this increment is driven by increased heart rate, augmented intrinsic ventricular contraction, or enhanced venous return. Two studies were performed in patients implanted with the HeartWare HVAD. In 11 patients, paced heart rate was increased to approximately 40 beats/min above baseline and then down to approximately 30 beats/min below baseline pacing rate (in pacemaker-dependent patients). Ten patients underwent tilt-table testing at 30°, 60°, and 80° passive head-up tilt for 3 min and then for a further 3 min after ankle flexion exercise. This regimen was repeated at 20° passive head-down tilt. Pump parameters, noninvasive hemodynamics, and 2-dimensional echocardiographic measures were recorded. Heart rate alteration by pacing did not affect LVAD flows or LV dimensions. LVAD pump flow decreased from baseline 4.9 ± 0.6 l/min to approximately 4.5 ± 0.5 l/min at each level of head-up tilt (p < 0.0001 analysis of variance). With active ankle flexion, LVAD flow returned to baseline. There was no significant change in flow with a 20° head-down tilt with or without ankle flexion exercise. There were no suction events. Centrifugal cfLVAD flows are not significantly affected by changes in heart rate, but they change significantly with body position and passive filling. Previously demonstrated exercise-induced changes in pump flows may be related to altered loading conditions, rather than changes in heart rate. Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Lagrangian coherent structures in the left ventricle in the presence of aortic valve regurgitation

NASA Astrophysics Data System (ADS)

di Labbio, Giuseppe; Vetel, Jerome; Kadem, Lyes

2017-11-01

Aortic valve regurgitation is a rather prevalent condition where the aortic valve improperly closes, allowing filling of the left ventricle of the heart to occur partly from backflow through the aortic valve. Although studies of intraventricular flow are rapidly gaining popularity in the fluid dynamics research community, much attention has been given to the left ventricular vortex and its potential for early detection of disease, particularly in the case of dilated cardiomyopathy. Notably, the subsequent flow in the left ventricle in the presence of aortic valve regurgitation ought to be appreciably disturbed and has yet to be described. Aortic valve regurgitation was simulated in vitro in a double-activation left heart duplicator and the ensuing flow was captured using two-dimensional time-resolved particle image velocimetry. Further insight into the regurgitant flow is obtained by computing attracting and repelling Lagrangian coherent structures. An interesting interplay between the two inflowing jets and their shear layer roll-up is observed for various grades of regurgitation. This study highlights flow features which may find use in further assessing regurgitation severity.

Mitral Valve Disease

MedlinePlus

... leaflets) that open and close, allowing blood to flow from your left atrium to your left ventricle ... does not open enough to allow sufficient blood flow. Usually this is the result of hardening (calcification) ...

[Quantitative Evaluation of Intracardiac Blood Flow by Left Ventricle Dynamic Anatovy Based On Exact Solutions of Non-Stationary Navier-Stocks Equations for Selforganized tornado-Like Flows of Viscous Incompresssible Fluid].

PubMed

Talygin, E A; Zazybo, N A; Zhorzholiany, S T; Krestinich, I M; Mironov, A A; Kiknadze, G I; Bokerya, L A; Gorodkov, A Y; Makarenko, V N; Alexandrova, S A

2016-01-01

New approach to intracardiac blood flow condition analysis based on geometric parameters of left ventricle flow channel has been suggested. Parameters, that used in this method, follow from exact solutions of nonstationary Navier-Stocks equations for selforganized tornado-like flows of viscous incompressible fluid. The main advantage of this method is considering dynamic anatomy of intracardiac cavity and trabeculae relief of left ventricle streamlined surface, both registered in a common mri-process, as flow condition indicator. Calculated quantity options that characterizes blood flow condition can be use as diagnostic criterias for estimation of violation in blood circulation function which entails heart ejection reduction. Developed approach allows to clarify heart jet organization mechanism and estimate the share of the tornado-like flow self-organization in heart ejection structure.

Low Transvalvular Flow Rate Predicts Mortality in Patients With Low-Gradient Aortic Stenosis Following Aortic Valve Intervention.

PubMed

Vamvakidou, Anastasia; Jin, Wenying; Danylenko, Oleksandr; Chahal, Navtej; Khattar, Rajdeep; Senior, Roxy

2018-03-09

This study aimed to assess the value of low transvalvular flow rate (FR) for the prediction of mortality compared with low stroke volume index (SVi) in patients with low-gradient (mean gradient: <40 mm Hg), low aortic valve area (<1 cm 2 ) aortic stenosis (AS) following aortic valve intervention. Transaortic FR defined as stroke volume/left ventricular ejection time is also a marker of flow; however, no data exist comparing the relative prognostic value of these 2 transvalvular flow markers in patients with low-gradient AS who had undergone valve intervention. We retrospectively followed prospectively assessed consecutive patients with low-gradient, low aortic valve area AS who underwent aortic valve intervention between 2010 and 2014 for all-cause mortality. Of the 218 patients with mean age 75 ± 12 years, 102 (46.8%) had low stroke volume index (SVi) (<35 ml/m 2 ), 95 (43.6%) had low FR (<200 ml/s), and 58 (26.6%) had low left ventricular ejection fraction <50%. The concordance between FR and SVi was 78.8% (p < 0.005). Over a median follow-up of 46.8 ± 21 months, 52 (23.9%) deaths occurred. Patients with low FR had significantly worse outcome compared with those with normal FR (p < 0.005). In patients with low SVi, a low FR conferred a worse outcome than a normal FR (p = 0.005), but FR status did not discriminate outcome in patients with normal SVi. By contrast, SVi did not discriminate survival either in patients with normal or low FR. Low FR was an independent predictor of mortality (p = 0.013) after adjusting for age, clinical prognostic factors, European System for Cardiac Operative Risk Evaluation II, dimensionless velocity index, left ventricular mass index, left ventricular ejection fraction, heart rate, time, type of aortic valve intervention, and SVi (p = 0.59). In patients with low-gradient, low valve area aortic stenosis undergoing aortic valve intervention, low FR, not low SVi, was an independent predictor of medium-term mortality. Copyright © 2018 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Flow Rate Through Pigtail Catheter Used for Left Heart Decompression in an Artificial Model of Extracorporeal Membrane Oxygenation Circuit.

PubMed

Kim, Won Ho; Hong, Tae Hee; Byun, Joung Hun; Kim, Jong Woo; Kim, Sung Hwan; Moon, Sung Ho; Park, Hyun Oh; Choi, Jun Young; Yang, Jun Ho; Jang, In Seok; Lee, Chung Eun; Yun, Jeong Hee

In refractory cardiogenic shock, veno-arterial extracorporeal membrane oxygenation (ECMO) can be initiated. Although left heart decompression can be accomplished by insertion of a left atrial (LA) or left ventricular (LV) cannula using a percutaneous pigtail catheter, the venting flow rate according to catheter size and ECMO flow rate is unknown. We developed an artificial ECMO circuit. One liter saline bag with its pressure set to 20 mm Hg was connected to ECMO to mimic LV failure. A pigtail catheter was inserted into the 1 L saline bag to simulate LV unloading. For each pigtail catheter size (5-8 Fr) and ECMO flow rate (2.0-4.0 L/min), the moving distance of an air bubble that was injected through a three-way stopcock was measured in the arterial pressure line between the pigtail catheter and ECMO inflow limb. The flow rate was then calculated. We obtained the following equation to estimate the pigtail catheter flow rate.Pigtail vent catheter flow rate (ml/min) = 8×ECMOflow rate(L /min)+9×pigtail catheter size(Fr)- 57This equation would aid in designing of a further study to determine optimal venting flow rate. To achieve optimal venting flow, our equation would enable selection of an adequate catheter size.

Nebivolol improves coronary flow reserve in patients with idiopathic dilated cardiomyopathy

PubMed Central

Erdogan, Dogan; Gullu, Hakan; Caliskan, Mustafa; Ciftci, Ozgur; Baycan, Semra; Yildirir, Aylin; Muderrisoglu, Haldun

2007-01-01

Background Impaired coronary flow reserve (CFR) is a significant predictor of poor prognosis in patients with idiopathic dilated cardiomyopathy (IDC). Nebivolol reduces mortality and morbidity in patients with heart failure and left ventricular dysfunction, including cases caused by IDC. Objective To assess the effects of nebivolol on CFR in patients with IDC. Methods CFR was measured in 21 clinically stable patients with IDC (mean (SD) ejection fraction 35.7 (6.2)) at baseline and after 1 month of treatment with nebivolol once daily. A control group of apparently healthy subjects who were matched for age and sex was used for comparison. Resting and hyperaemic coronary flows were measured using transthoracic second‐harmonic Doppler echocardiography. None of the subjects had any systemic disease. Results After 1 month of treatment, heart rate was reduced significantly (p<0.001). The blood pressure was decreased significantly (p<0.001). The left ventricular end‐diastolic diameter and stroke volume were not changed significantly, but end‐systolic diameter was decreased significantly (p<0.05). Resting rate–pressure product was lower after treatment with nebivolol, but dipyridamole‐induced change was not influenced by the treatment. Nebivolol treatment reduced significantly coronary velocities at rest (p<0.02) and also caused a significant increase in coronary velocities after dipyridamole (p<0.02), leading to a greater CFR (2.02 (0.35) vs 2.61 (0.43), p<0.001). Nebivolol induced an absolute increase of 6% in the CFR in 17 of 21 patients (80.9%). Conclusions In patients with IDC, 1 month of treatment with nebivolol induces a marked increase in CFR. PMID:17065184

Improvement on the auxiliary total artificial heart (ATAH) left chamber design.

PubMed

Andrade, Aron; Fonseca, Jeison; Legendre, Daniel; Nicolosi, Denys; Biscegli, Jose; Pinotti, Marcos; Ohashi, Yukio; Nosé, Yukihiko

2003-05-01

The auxiliary total artificial heart (ATAH) is an electromechanically driven artificial heart with reduced dimensions, which is able to be implanted in the right thoracic or abdominal cavities of an average human patient without removing the natural heart or the heart neurohumoral inherent control mechanism for the arterial pressure. This device uses a brushless direct current motor and a mechanical actuator (roller screw) to move two diaphragms. The ATAH's beating frequency is regulated through the change of the left preload, based on Frank-Starling's law, assisting the native heart in obtaining adequate blood flow. The ATAH left and right stroke volumes are 38 ml and 34 ml, respectively, giving approximately 5 L/min of cardiac output at 160 bpm. Flow visualization studies were performed in critical areas on the ATAH left chamber. A closed circuit loop was used with water and glycerin (37%) at 25 degrees C. Amberlite particles (80 mesh) were illuminated by a 1 mm planar helium-neon laser light. With left mean preload fixed at 10 mm Hg and the afterload at 100 mm Hg, the heart rate varied from 60 to 200 bpm. Two porcine valves were used on the inlet and outlet ports. The flow pattern images were obtained using a color micro-camera and a video recorder. Subsequently, these images were digitized using a PC computer. A persistent stagnant flow was detected in the left chamber inlet port. After improvement on the left chamber design, this stagnant flow disappeared.

Blood flow of the right and left submandibular gland during unilateral carotid artery occlusion in rat: role of nitric oxide.

PubMed

Vág, J; Hably, C; Fazekas, A; Bartha, J

1999-01-01

The aim of the present study was to investigate the effect of unilateral carotid artery occlusion on the blood flow of submandibular gland in anesthetized rats and identify the role of nitric oxide (NO) in blood flow changes after the artery occlusion. L-NAME (N omega-nitro-L-arginine-methyl-ester; 10 mg/kg/day, per os) dissolved in tap water was used to block nitric oxide synthase. Glandular blood flow was measured using Sapirstein's indicator (86Rb) distribution technique. In the control animals the blood flow of left (ligated side) submandibular gland was lower than in the right (unligated side) one (right: 76.4+/-15.4 ml/min/100 g, 64.1+/-13.4 ml/min/100 g, p<0.01). The blood flow of submandibular glands decreased in NOS blocked group versus control. The vascular resistance after L-NAME treatment was elevated (control: 11+/-2.3 R/kg, L-NAME: 17.5+/-4.1 R/kg, p<0.001). In L-NAME group the difference between blood flow value of the left and right submandibular gland was significantly lower than in the control group (control: -16%, NAME: -8%, p<0.01). The maintenance of the blood flow in the left submandibular gland during ligation of the left common carotid artery could be due to the good vascular anastomotic system at these regions and adaptation of the submandibular vessels to the decreased perfusion pressure. Nitric oxide may have a role in the regulation of blood flow tinder this condition.

L wave in echo Doppler.

PubMed

Kumar, Vipin; Jose, John; Jose, V Jacob

2014-01-01

62-year-old female presented with progressive dyspnea NYHA class III for six months. Echocardiography showed normal left ventricular (LV) systolic function, mild biatrial enlargement, an L wave in pulse wave Doppler at mitral inflow and in M mode echocardiography across mitral valve. Tissue Doppler imaging at medial mitral annulus showed an L' wave in mid diastole in addition to E' and A' wave. An L wave in pulse wave Doppler and M mode echocardiography represents continued pulmonary vein mid diastolic flow through the left atrium in to LV across mitral valve after early rapid filling. Presence of an L' wave in these patients associated with higher E/E' is indicative of advance diastolic dysfunction with elevated filling pressures. Copyright © 2014 Cardiological Society of India. Published by Elsevier B.V. All rights reserved.

Prevalence and Predictive Value of Microvascular Flow Abnormalities after Successful Contemporary Percutaneous Coronary Intervention in Acute ST-Segment Elevation Myocardial Infarction.

PubMed

Aggarwal, Sourabh; Xie, Feng; High, Robin; Pavlides, Gregory; Porter, Thomas R

2018-06-01

Although microvascular flow abnormalities have been observed following epicardial recanalization in acute ST-segment elevation myocardial infarction (STEMI), the prevalence and severity of these abnormalities in the current era of rapid percutaneous coronary intervention (PCI) has not been evaluated. The objective of this study was to assess microvascular perfusion (MVP) following successful primary PCI in patients with STEMI and how it affects clinical outcome. In this single-center, retrospective study, 170 patients who successfully underwent emergent PCI for STEMI were assessed using real-time myocardial contrast echocardiography using a continuous infusion of intravenous commercial microbubbles (3% Definity). Three patterns of myocardial contrast replenishment were observed following intermittent high-mechanical index impulses: infarct zone replenishment within 4 sec (normal MVP), delays in contrast replenishment but normal plateau intensity (delayed MVP [dMVP]), and both delays in replenishment and reduced plateau intensity (microvascular obstruction [MVO]). Changes in left ventricular ejection fraction at 6 months and clinical event rate at 12 months (death, recurrent infarction, need for defibrillator placement, or heart failure admission) were compared. Normal MVP was seen in 62 patients (36%), dMVP in 49 (29%), and MVO in 59 (35%). Left anterior descending coronary artery infarct location was the only parameter independently associated with dMVP or MVO, independent of age, cardiac risk factors, door-to-dilation time, pre-PCI Thrombolysis In Myocardial Infarction flow grade, and thrombus burden. A dMVP pattern had a similar reduction in left ventricular ejection fraction as MVO at hospital discharge but had recovery of left ventricular ejection fraction at 6 months and a greater than fourfold lower event rate than the MVO group (P < .001). MVO and dMVP are frequently seen following contemporary successful PCI for STEMI, especially following left anterior descending coronary artery infarction. Despite a similar area at risk, a dMVP pattern has better functional recovery and clinical outcome than MVO. Copyright © 2018 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.

Mechanical Strain Determines Cilia Length, Motility, and Planar Position in the Left-Right Organizer.

PubMed

Chien, Yuan-Hung; Srinivasan, Shyam; Keller, Ray; Kintner, Chris

2018-05-07

The Xenopus left-right organizer (LRO) breaks symmetry along the left-right axis of the early embryo by producing and sensing directed ciliary flow as a patterning cue. To carry out this process, the LRO contains different ciliated cell types that vary in cilia length, whether they are motile or sensory, and how they position their cilia along the anterior-posterior (A-P) planar axis. Here, we show that these different cilia features are specified in the prospective LRO during gastrulation, based on anisotropic mechanical strain that is oriented along the A-P axis, and graded in levels along the medial-lateral axis. Strain instructs ciliated cell differentiation by acting on a mesodermal prepattern present at blastula stages, involving foxj1. We propose that differential strain is a graded, developmental cue, linking the establishment of an A-P planar axis to cilia length, motility, and planar location during formation of the Xenopus LRO. Copyright © 2018 Elsevier Inc. All rights reserved.

Durability of central aortic valve closure in patients with continuous flow left ventricular assist devices.

PubMed

McKellar, Stephen H; Deo, Salil; Daly, Richard C; Durham, Lucian A; Joyce, Lyle D; Stulak, John M; Park, Soon J

2014-01-01

A competent aortic valve is essential to providing effective left ventricular assist device support. We have adopted a practice of central aortic valve closure by placing a simple coaptation stitch at left ventricular assist device implantation in patients with significant aortic insufficiency. We conducted a follow-up study to evaluate the efficacy and durability of this procedure. The study included patients who had undergone continuous flow left ventricular assist device implantation. The patients were divided into 2 groups, those who did not require any aortic procedure because the valve was competent and those who underwent central aortic valve closure for mild or greater aortic regurgitation. The clinical endpoints were mortality, progression or recurrence of aortic insufficiency, and reoperation for aortic valve pathologic features. Aortic insufficiency was measured qualitatively from mild to severe on a scale of 0 to 5. A total of 123 patients received continuous flow left ventricular assist devices from February 2007 to August 2011. Of those, 18 (15%) underwent central aortic valve closure at left ventricular assist device implantation because of significant aortic insufficiency (1.8 ± 1.4) and 105 who did not (competent aortic valve, 0.15 ± 0.43; P < .01). At follow-up (median, 312 days; range, 0-1429 days), the mean aortic insufficiency score remained low for the patients with central aortic valve closure (0.27 ± 0.46) in contrast to those without central aortic valve closure who experienced aortic insufficiency progression (0.78 ± 0.89; P = .02). In addition, the proportion of patients with more than mild aortic insufficiency was significantly less in the central aortic valve closure group (0% vs 18%; P = .05). The patients in the central aortic valve closure group were significantly older and had a greater incidence of renal failure at baseline. The 30-day mortality was greater in the central aortic valve closure group, but the late survival was similar between the 2 groups. No reoperations were required for recurrent aortic insufficiency. The results of our study have shown that repair of aortic insufficiency with a simple central coaptation stitch is effective and durable in left ventricular assist device-supported patients, with follow-up extending into 2 years. Although aortic insufficiency progressed over time in those with minimal native valve regurgitation initially, no such progression was noted in those with central aortic valve closure. Additional investigation is needed to evaluate whether prophylactic central aortic valve closure should be performed at left ventricular assist device implantation to avoid problematic aortic regurgitation developing over time, in particular in patients undergoing left ventricular assist device implantation for life-long (destination therapy) support. Copyright © 2014 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

Regional cerebral blood flow and abnormal eating behavior in Prader-Willi syndrome.

PubMed

Ogura, Kaeko; Fujii, Toshikatsu; Abe, Nobuhito; Hosokai, Yoshiyuki; Shinohara, Mayumi; Fukuda, Hiroshi; Mori, Etsuro

2013-05-01

Prader-Willi syndrome (PWS) is a genetically determined neurodevelopmental disorder and is generally regarded as a genetic model of obesity. Individuals with PWS exhibit behavioral symptoms including temper tantrums, rigid thinking, and compulsive behavior. The most striking feature of PWS is abnormal eating behavior, including hyperphagia, intense preoccupation with food, and incessant food seeking. To explore brain regions associated with the behavioral symptoms of PWS, we investigated differences in resting-state regional cerebral blood flow (rCBF) between individuals with PWS and healthy controls. Correlation analyses were also performed to examine the relationship between rCBF and altered eating behavior in PWS individuals. Twelve adults with PWS and 13 age- and gender-matched controls underwent resting-state single photon emission computerized tomography (SPECT) with N-isopropyl-p-[(123)I] iodoamphetamine (IMP). The rCBF data were analyzed on a voxel-by-voxel basis using SPM5 software. The results demonstrated that compared with controls, individuals with PWS had significantly lower rCBF in the right thalamus, left insular cortex, bilateral lingual gyrus, and bilateral cerebellum. They had significantly higher rCBF in the right inferior frontal gyrus, left middle/inferior frontal gyrus (anterior and posterior clusters), and bilateral angular gyrus. Additionally, rCBF in the left insula, which was significantly lower in PWS individuals, was negatively correlated with the eating behavior severity score. These results suggest that specific brain regions, particularly the left insula, may be partly responsible for the behavioral symptoms in PWS. Copyright © 2012 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.

Left-turn phase: permissive, protected, or both? A quasi-experimental design in New York City.

PubMed

Chen, Li; Chen, Cynthia; Ewing, Reid

2015-03-01

The practice of left-turn phasing selection (permissive, protected-only, or both) varies from one locality to another. The literature evidence on this issue is equally mixed and insufficient. In this study, we evaluate the safety impacts of changing left-turn signal phasing from permissive to protected/permissive or protected-only at 68 intersections in New York City using a rigorous quasi-experimental design accompanied with regression modeling. Changes in police reported crashes including total crashes, multiple-vehicle crashes, left-turn crashes, pedestrian crashes and bicyclist crashes were compared between before period and after period for the treatment group and comparison group by means of negative binomial regression using a Generalized Estimating Equations (GEE) technique. Confounding factors such as the built environment characteristics that were not controlled in comparison group selection are accounted for by this approach. The results show that the change of permissive left-turn signal phasing to protected/permissive or protected-only signal phasing does not result in a significant reduction in intersection crashes. Though the protected-only signal phasing does reduce the left-turn crashes and pedestrian crashes, this reduction was offset by a possible increase in over-taking crashes. These results suggest that left-turn phasing should not be treated as a universal solution that is always better than the permissive control for left-turn vehicles. The selection and implementation of left-turn signal phasing needs to be done carefully, considering potential trade-offs between safety and delay, and many other factors such as geometry, traffic flows and operations. Copyright © 2014 Elsevier Ltd. All rights reserved.

Cilia in vertebrate left-right patterning.

PubMed

Dasgupta, Agnik; Amack, Jeffrey D

2016-12-19

Understanding how left-right (LR) asymmetry is generated in vertebrate embryos is an important problem in developmental biology. In humans, a failure to align the left and right sides of cardiovascular and/or gastrointestinal systems often results in birth defects. Evidence from patients and animal models has implicated cilia in the process of left-right patterning. Here, we review the proposed functions for cilia in establishing LR asymmetry, which include creating transient leftward fluid flows in an embryonic 'left-right organizer'. These flows direct asymmetric activation of a conserved Nodal (TGFβ) signalling pathway that guides asymmetric morphogenesis of developing organs. We discuss the leading hypotheses for how cilia-generated asymmetric fluid flows are translated into asymmetric molecular signals. We also discuss emerging mechanisms that control the subcellular positioning of cilia and the cellular architecture of the left-right organizer, both of which are critical for effective cilia function during left-right patterning. Finally, using mosaic cell-labelling and time-lapse imaging in the zebrafish embryo, we provide new evidence that precursor cells maintain their relative positions as they give rise to the ciliated left-right organizer. This suggests the possibility that these cells acquire left-right positional information prior to the appearance of cilia.This article is part of the themed issue 'Provocative questions in left-right asymmetry'. © 2016 The Author(s).

High frame rate synthetic aperture vector flow imaging for transthoracic echocardiography

NASA Astrophysics Data System (ADS)

Villagómez-Hoyos, Carlos A.; Stuart, Matthias B.; Bechsgaard, Thor; Nielsen, Michael Bachmann; Jensen, Jørgen Arendt

2016-04-01

This work presents the first in vivo results of 2-D high frame rate vector velocity imaging for transthoracic cardiac imaging. Measurements are made on a healthy volunteer using the SARUS experimental ultrasound scanner connected to an intercostal phased-array probe. Two parasternal long-axis view (PLAX) are obtained, one centred at the aortic valve and another centred at the left ventricle. The acquisition sequence was composed of 3 diverging waves for high frame rate synthetic aperture flow imaging. For verification a phantom measurement is performed on a transverse straight 5 mm diameter vessel at a depth of 100 mm in a tissue-mimicking phantom. A flow pump produced a 2 ml/s constant flow with a peak velocity of 0.2 m/s. The average estimated flow angle in the ROI was 86.22° +/- 6.66° with a true flow angle of 90°. A relative velocity bias of -39% with a standard deviation of 13% was found. In-vivo acquisitions show complex flow patterns in the heart. In the aortic valve view, blood is seen exiting the left ventricle cavity through the aortic valve into the aorta during the systolic phase of the cardiac cycle. In the left ventricle view, blood flow is seen entering the left ventricle cavity through the mitral valve and splitting in two ways when approximating the left ventricle wall. The work presents 2-D velocity estimates on the heart from a non-invasive transthoracic scan. The ability of the method detecting flow regardless of the beam angle could potentially reveal a more complete view of the flow patterns presented on the heart.

Effect of antiischemic therapy on coronary flow reserve and the pressure-maximal coronary flow relationship in anesthetized swine.

PubMed

McFalls, E O; Duncker, D J; Sassen, L M; Gho, B C; Verdouw, P D

1991-12-01

The effect of nifedipine (0.5, 1.0, and 2.0 micrograms/kg/min), metoprolol (0.1, 0.5, and 1.0 mg/kg), the beta 1-selective adrenoceptor partial agonist epanolol (10, 50, and 200 micrograms/kg), or equivalent volumes of isotonic saline (n = 6, in each group), on coronary blood flow capacity were studied in anesthetized swine. Intracoronary bolus injections of adenosine (20 micrograms/kg/0.2 ml) were administered without and during three levels of coronary stenosis, prior to and following each dose of drug, to obtain maximal coronary blood flows at different perfusion pressures in the autoregulatory range. Coronary perfusion pressures were varied by partial inflation of a balloon around the left anterior descending coronary artery. Special care was taken that the stenoses not lead to myocardial ischemia. Three indices of coronary blood flow capacity were used: absolute coronary flow reserve (ACFR, the ratio of maximal to resting coronary blood flow), the slope and the extrapolated pressure at zero flow (Pzf) of the pressure-maximal coronary flow (PMCF) relationship, and relative coronary flow reserve (RCFR, the ratio of maximal coronary blood flow with a stenosis to maximal coronary blood flow without a stenosis) at two of the three levels of stenosis. Nifedipine decreased ACFR from 4.5 +/- 1.9 to 1.9 +/- 0.3 (mean +/- SD; p less than 0.05), reflecting in part the increase in resting coronary blood flow. The nifedipine-induced changes in maximal coronary blood flow were not only due to a drop in perfusion pressure, as the slope of the PMCF relationship decreased from 2.27 +/- 0.49 ml/(min.mm Hg) to 1.54 +/- 0.51 ml/(min.mm Hg) (p less than 0.05), and Pzf decreased from 30 +/- 4 mm Hg to 20 +/- 7 mm Hg (p less than 0.05). Consequently, calculated maximal coronary blood flow was attenuated from 114 +/- 31 ml/min to 93 +/- 37 ml/min at 80 mm Hg, but was enhanced from 23 +/- 13 to 37 +/- 24 ml/min at 40 mm Hg coronary perfusion pressure. In concert with the change in the PMCF relationship, RCFR at equivalent severe stenosis increased from 0.33 +/- 0.06 to 0.47 +/- 0.10 (p less than 0.05). No changes were observed with metoprolol, epanolol, or saline. The effect of nifedipine on the PMCF relationship not only provides a mechanism for the drug's antiischemic action, but should also be considered in the interpretation of coronary flow reserve measurements in patients on nifedipine treatment.

Individualized model predicts brain current flow during transcranial direct-current stimulation treatment in responsive stroke patient.

PubMed

Datta, Abhishek; Baker, Julie M; Bikson, Marom; Fridriksson, Julius

2011-07-01

Although numerous published reports have demonstrated the beneficial effects of transcranial direct-current stimulation (tDCS) on task performance, fundamental questions remain regarding the optimal electrode configuration on the scalp. Moreover, it is expected that lesioned brain tissue will influence current flow and should therefore be considered (and perhaps leveraged) in the design of individualized tDCS therapies for stroke. The current report demonstrates how different electrode configurations influence the flow of electrical current through brain tissue in a patient who responded positively to a tDCS treatment targeting aphasia. The patient, a 60-year-old man, sustained a left hemisphere ischemic stroke (lesion size = 87.42 mL) 64 months before his participation. In this study, we present results from the first high-resolution (1 mm(3)) model of tDCS in a brain with considerable stroke-related damage; the model was individualized for the patient who received anodal tDCS to his left frontal cortex with the reference cathode electrode placed on his right shoulder. We modeled the resulting brain current flow and also considered three additional reference electrode positions: right mastoid, right orbitofrontal cortex, and a "mirror" configuration with the anode over the undamaged right cortex. Our results demonstrate the profound effect of lesioned tissue on resulting current flow and the ability to modulate current pattern through the brain, including perilesional regions, through electrode montage design. The complexity of brain current flow modulation by detailed normal and pathologic anatomy suggest: (1) That computational models are critical for the rational interpretation and design of individualized tDCS stroke-therapy; and (2) These models must accurately reproduce head anatomy as shown here. Copyright © 2011 Elsevier Inc. All rights reserved.

When should fractional flow reserve be performed to assess the significance of borderline coronary artery lesions: Derivation of a simplified scoring system.

PubMed

Matar, Fadi A; Falasiri, Shayan; Glover, Charles B; Khaliq, Asma; Leung, Calvin C; Mroue, Jad; Ebra, George

2016-11-01

To derive a simplified scoring system (SSS) that can assist in selecting patients who would benefit from the application of fractional flow reserve (FFR). Angiographers base decisions to perform FFR on their interpretation of % diameter stenosis (DS), which is subject to variability. Recent studies have shown that the amount of myocardium at jeopardy is an important factor in determining the degree of hemodynamic compromise. We conducted a retrospective multivariable analysis to identify independent predictors of hemodynamic compromise in 289 patients with 317 coronary vessels undergoing FFR. A SSS was derived using the odds ratios as a weighted factor. The receiver operator characteristics curve was used to identify the optimal cutoff (≥3) to discern a functionally significant lesion (FFR≤0.8). Male gender, left anterior descending artery apical wrap, disease proximal to lesion, minimal lumen diameter and % DS predicted abnormal FFR (≤0.8) and lesion location in the left circumflex predicted a normal FFR. Using a cutoff score of ≥3 on the SSS, a specificity of 90.4% (95% CI: 83.0-95.3) and a sensitivity of 38.0% (95% CI: 31.5-44.9) was generated with a positive predictive value of 89.0% (95% CI: 80.7%-94.6%) and negative predictive value of 41.6% (95% CI: 35.1%-48.3%). The decision to use FFR should be based not only on the % DS but also the size of the myocardial mass jeopardized. A score of ≥3 on the SSS should prompt further investigation with a pressure wire. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Enhanced motor learning with bilateral transcranial direct current stimulation: Impact of polarity or current flow direction?

PubMed

Naros, Georgios; Geyer, Marc; Koch, Susanne; Mayr, Lena; Ellinger, Tabea; Grimm, Florian; Gharabaghi, Alireza

2016-04-01

Bilateral transcranial direct current stimulation (TDCS) is superior to unilateral TDCS when targeting motor learning. This effect could be related to either the current flow direction or additive polarity-specific effects on each hemisphere. This sham-controlled randomized study included fifty right-handed healthy subjects in a parallel-group design who performed an exoskeleton-based motor task of the proximal left arm on three consecutive days. Prior to training, we applied either sham, right anodal (a-TDCS), left cathodal (c-TDCS), concurrent a-TDCS and c-TDCS with two independent current sources and return electrodes (double source (ds)-TDCS) or classical bilateral stimulation (bi-TDCS). Motor performance improved over time for both unilateral (a-TDCS, c-TDCS) and bilateral (bi-TDCS, ds-TDCS) TDCS montages. However, only the two bilateral paradigms led to an improvement of the final motor performance at the end of the training period as compared to the sham condition. There was no difference between the two bilateral stimulation conditions (bi-TDCS, ds-TDCS). Bilateral TDCS is more effective than unilateral stimulation due to its polarity-specific effects on each hemisphere rather than due to its current flow direction. This study is the first systematic evaluation of stimulation polarity and current flow direction of bi-hemispheric motor cortex TDCS on motor learning of proximal upper limb muscles. Copyright © 2016 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Flow Visualization Studies in the Novacor Left Ventricular Assist System CRADA PC91-002, Final Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Borovetz, H.S.; Shaffer, F.; Schaub, R.

This paper discusses a series of experiments to visualize and measure flow fields in the Novacor left ventricular assist system (LVAS). The experiments utilize a multiple exposure, optical imaging technique called fluorescent image tracking velocimetry (FITV) to hack the motion of small, neutrally-buoyant particles in a flowing fluid.

Response of the Cardiovascular System to Vibration and Combined Stresses

DTIC Science & Technology

1975-08-31

Canines were chronically instrumented for continuous measurements of ascending aortic flow ( Zepeda ), left ventricular pressure (Konigsberg), circum- flex...different animals. Each dog was chronically instrumented for continuous measuremernt of ascending aortic flow ( Zepeda ), left ventricular pressure...vibration protocol as those animals restrained vertically. METHODS Canines (16 to 22 kg) were chronically instrumented with electromagnetic flow cuffs ( Zepeda

Integrated quadruple stress echocardiography.

PubMed

Picano, Eugenio; Morrone, Doralisa; Scali, Maria C; Huqi, Alda; Coviello, Katia; Ciampi, Quirino

2018-04-11

Stress Echocardiography (SE) is an established diagnostic technique. For 40 years, the cornerstone of the technique has been the detection of regional wall motion abnormalities (RWMA), due to the underlying physiologically-relevant epicardial coronary artery stenosis. In the last decade, three new parameters (more objective than RWMA) have shown the potential to integrate and comple- ment RWMA: 1- B-lines, also known as ultrasound lung comets, as a marker of extra-vascular lung water, measured using lung ultrasound with the 4-site simplified scan symmetrically of the antero- lateral thorax on the third intercostal space, from mid-axillary to anterior axillary and mid- clavicular line; 2-left ventricular contractile reserve (LVCR), assessed as the peak stress/rest ratio of left ventricular force, also known as elastance (systolic arterial pressure by cuff sphygmomanome- ter/end-systolic volume from 2D echocardiography); 3- coronary flow velocity reserve (CFVR) on left anterior descending coronary artery, calculated as peak stress/rest ratio of diastolic peak flow velocity assessed using pulsed-wave Doppler. The 4 parameters (RWMA, B-lines, LVCR and CFVR) now converge conceptually, logistically, and methodologically in the Integrated Quadruple (IQ)-SE. IQ-SE optimizes the versatility of SE to include in a one-stop shop the core "ABCD" (Asynergy+B-lines+Contractile reserve+Doppler flowmetry) protocol. It allows a synoptic assess- ment of parameters mirroring the epicardial artery stenosis (RWMA), interstitial lung water (B- lines), myocardial function (LVCR) and small coronary vessels (CFVR). Each variable has a clear clinical correlate, different and complementary to all others: RWMA identify an ischemic vs non- ischemic heart; B-lines a wet vs dry lung; LVCR a strong vs weak heart; CFVR a warm vs cold heart. IQ-SE is highly feasible, with minimal increase in the imaging and analysis time, and obvi- ous diagnostic and prognostic impact also beyond coronary artery disease - especially in heart fail- ure. Large scale effectiveness studies with IQ-SE are now under way with the Stress Echo 2020 study, and will provide the necessary evidence base prior to large scale acceptance of the tech- nique.

A pilot study of the relationship between Doppler-estimated carotid and brachial artery flow and cardiac index.

PubMed

Weber, U; Glassford, N J; Eastwood, G M; Bellomo, R; Hilton, A K

2015-10-01

We measured carotid and brachial artery blood flow by Doppler ultrasound in 11 human volunteers, and related these to cardiac index and to each other. The median (IQR [range]) carotid arterial blood flow was 0.334 (0.223-0.381 [0.052-0.563]) l.min(-1) on the right and 0.315 (0.223-0.369 [0.061-0.690]) l.min(-1) on the left. The brachial arterial blood flow was 0.049 (0.033-0.062 [0.015-0.204]) l.min(-1) on the right and 0.039 (0.027-0.054 [0.011-0.116]) on the left. Cardiac index was 3.2 (2.8-3.5 [1.9-5.4]) l.min(-1) .m(-2) . There was a moderate to good correlation between right-and left-sided flows (brachial: ρ = 0.45; carotid: ρ = 0.567). Brachial and carotid flow had no or a negative correlation with cardiac index (right brachial: ρ = -0.145, left brachial: ρ = -0.349; right carotid: ρ = -0.376, left carotid: ρ = -0.285). In contrast to some previous studies, we found that Doppler-estimated peripheral arterial blood flows only show a weak correlation with cardiac index and cannot be used to provide non-invasive estimates of cardiac index in man. © 2015 The Association of Anaesthetists of Great Britain and Ireland.

Effects of graded doses of epinephrine on regional myocardial blood flow during cardiopulmonary resuscitation in swine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, C.G.; Werman, H.A.; Davis, E.A.

1987-02-01

Although epinephrine has been shown to improve myocardial blood flow during cardiopulmonary resuscitation (CPR), the effects of standard as well as larger doses of epinephrine on regional myocardial blood flow have not been examined. In this study we compared the effects of various doses of epinephrine on regional myocardial blood flow after a 10 min arrest in a swine preparation. Fifteen swine weighing greater than 15 kg each were instrumented for regional myocardial blood flow measurements with tracer microspheres. Regional blood flow was measured during normal sinus rhythm. After 10 min of ventricular fibrillation, CPR was begun and regional myocardialmore » blood flow was determined. Animals were then randomly assigned to receive 0.02, 0.2, or 2.0 mg/kg epinephrine by peripheral injection. One minute after drug administration, regional myocardial blood flow measurements were repeated. The adjusted regional myocardial blood flows (ml/min/100 g) for animals given 0.02, 0.2, and 2.0 mg/kg epinephrine, respectively, were as follows: left atrium, 0.9, 67.4, and 58.8; right atrium, 0.3, 46.2, and 38.5; right ventricle, 0.7, 82.3, and 66.9; right interventricular septum, 1.7, 125.5, and 99.1; left interventricular septum, 2.8, 182.8, 109.5; mesointerventricular septum, 16.8, 142.2, and 79.2; left ventricular epicardium, 19.2, 98.5 and 108.7; left ventricular mesocardium, 22.8, 135.0, and 115.8; and left ventricular endocardium, 2.5, 176.1, and 132.9). All comparisons between the groups receiving 0.02 and 0.2 mg/kg epinephrine were statistically significant (p less than .05).« less

Neuromodulation therapy does not influence blood flow distribution or left-ventricular dynamics during acute myocardial ischemia.

PubMed

Kingma, J G; Linderoth, B; Ardell, J L; Armour, J A; DeJongste, M J; Foreman, R D

2001-08-13

Electrical stimulation of the dorsal aspect of the upper thoracic spinal cord is used increasingly to treat patients with angina pectoris refractory to conventional therapeutic strategies. The purpose of this study was to determine whether spinal cord stimulation (SCS) in dogs affects regional myocardial blood flow and left-ventricular (LV) function before and during transient obstruction of the left anterior descending coronary artery (LAD). In anesthetized dogs, regional myocardial blood flow distribution was determined using radiolabeled microspheres and left-ventricular function was measured by impedance-derived pressure-volume loops. SCS was accomplished by stimulating the dorsal T1-T2 segments of the spinal cord using epidural bipolar electrodes at 90% of motor threshold (MT) (50 Hz, 0.2-ms duration). Effects of 5-min SCS were assessed under basal conditions and during 4-min occlusion of the LAD. SCS alone evoked no change in regional myocardial blood flow or cardiovascular indices. Transient LAD occlusion significantly diminished blood flow within ischemic, but not in non-ischemic myocardial tissue. Left ventricular pressure-volume loops were shifted rightward during LAD occlusion. Cardiac indices were altered similarly during LAD occlusion and concurrent SCS. SCS does not influence the distribution of blood flow within the non-ischemic or ischemic myocardium. Nor does it modify LV pressure-volume dynamics in the anesthetized experimental preparation.

Fluid-structure interaction in the left ventricle of the human heart coupled with mitral valve

NASA Astrophysics Data System (ADS)

Meschini, Valentina; de Tullio, Marco Donato; Querzoli, Giorgio; Verzicco, Roberto

2016-11-01

In this paper Direct Numerical Simulations (DNS), implemented using a fully fluid-structure interaction model for the left ventricle, the mitral valve and the flowing blood, and laboratory experiments are performed in order to cross validate the results. Moreover a parameter affecting the flow dynamics is the presence of a mitral valve. We model two cases, one with a natural mitral valve and another with a prosthetic mechanical one. Our aim is to understand their different effects on the flow inside the left ventricle in order to better investigate the process of valve replacement. We simulate two situations, one of a healthy left ventricle and another of a failing one. While in the first case the flow reaches the apex of the left ventricle and washout the stagnant fluid with both mechanical and natural valve, in the second case the disturbance generated by the mechanical leaflets destabilizes the mitral jet, thus further decreasing its capability to penetrate the ventricular region and originating heart attack or cardiac pathologies in general.

The influence of side branch stenosis on fractional flow reserve assessment of the main branch in a swine model.

PubMed

Oh, Jun-Hyok; Song, Seunghwan; Kim, Changhoon; Kim, Jeongsu; Sup Park, Jin; Won Lee, Hye; Hyun Choi, Jung; Cheol Lee, Han; Soo Cha, Kwang; Jong Hong, Taek

2017-02-01

The aim of this study was to explore the effect of one stenosis in a daughter artery on the fractional flow reserve (FFR) of another stenosis parallels in side branch. The impact of one stenosis on the FFR of another parallel stenosis has not been evaluated. The proximal segments of the left anterior descending (LAD) and left circumflex (LCX) arteries were exposed and encircled with a Teflon pledget complex in seven swine (55-70 kg). Five degrees of stenosis (to approximate angiographic diameter stenoses of 0%, 25%, 50%, 75%, and 100%) were made by tightening the pledgets. FFR was evaluated simultaneously in the LAD and the LCX with two pressure wires in each coronary artery. A mixed-effects linear model was used to evaluate the association between the FFR values. A total of 115 paired FFR values were obtained. The FFR of the LAD and LCX were not significantly associated with each other (F = 0.237 and P = 0.627 for the LCX FFR to predict the LAD FFR; F = 0.541 and P = 0.463 for the LAD FFR to predict the LCX FFR). The individual FFR values of each parallel stenosis in the LAD and the LCX were not significantly influenced by each other. This relationship was independent of the mean aortic pressure and heart rate. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Vicious circle between progressive right ventricular dilatation and pulmonary regurgitation in patients after tetralogy of Fallot repair? Right heart enlargement promotes flow reversal in the left pulmonary artery.

PubMed

Kato, Atsuko; Drolet, Christian; Yoo, Shi-Joon; Redington, Andrew N; Grosse-Wortmann, Lars

2016-06-07

The left pulmonary artery (LPA) contributes more than the right (RPA) to total pulmonary regurgitation (PR) in patients after tetralogy of Fallot (TOF) repair, but the mechanism of this difference is not well understood. This study aimed to analyze the interplay between heart and lung size, mediastinal geometry, and differential PR. Forty-eight Cardiovascular Magnetic Resonance (CMR) studies in patients after TOF repair were analyzed. In addition to the routine blood flow and ventricular volume quantification cardiac angle between the thoracic anterior-posterior line and the interventricular septum, right and left lung areas as well as right and left hemithorax areas were measured on an axial image. Statistical analysis was performed to compare flow parameters between RPA and LPA and to assess correlation among right ventricular volume, pulmonary blood flow parameters and lung area. There was no difference between LPA and RPA diameters. The LPA showed significantly less total forward flow (2.49 ± 0.87 L/min/m(2) vs 2.86 ± 0.89 L/min/m(2); p = 0.02), smaller net forward flow (1.40 ± 0.51 vs 1.89 ± 0.60 mL/min/m(2); p = <0.001), and greater regurgitant fraction (RF) (34 ± 10 % vs 43 ± 12 %; p = 0.001) than the RPA. There was no difference in regurgitant flow volume between RPA and LPA (p = 0.29). Indexed right ventricular end-diastolic volume (RVEDVi) correlated with LPA RF (R = 0.48, p < 0.001), but not with RPA RF (p = 0.09). Larger RVEDVi correlated with a more leftward cardiac axis (R = 0.46, p < 0.001) and with smaller left lung area (R = -0.58, p < 0.001). LPA RF, but not RPA RF, correlated inversely with left lung area (R = -0.34, p = 0.02). The follow-up CMRs in 20 patients showed a correlation of the rate of RV enlargement with the rates of LPA RF worsening (R = 0.50, p = 0.03), and of increasing left lung compression (R = -0.55, p = 0.012). An enlarged and levorotated heart is associated with left lung compression and impaired flow into the left lung.

Selective hypertrophy of the lobus caudatus as a novel approach enabling extended right hepatectomy in the presence of a non-perfused left lateral liver lobe.

PubMed

Atanasov, Georgi; Schmelzle, Moritz; Thelen, Armin; Wiltberger, Georg; Hau, Hans-Michael; Krenzien, Felix; Petersen, Tim-Ole; Moche, Michael; Jonas, Sven

2014-08-01

Portal vein embolization (PVE) is a well-established technique to enhance functional hepatic reserves of segments II and III before curative extended right hepatectomy for tumors of the right liver lobe. However, an adequate hepatopetal flow of the left lateral portal vein branches is required for a sufficient PVE-associated hypertrophy. Here, we report a 65-year old patient suffering from a locally advanced intrahepatic cholangiocarcinoma in the right liver lobe and segment IV. A curative extended right hepatectomy after preoperative PVE of liver segments IV-VIII was initially impossible because of partial thrombosis of the left lateral portal vein branches resulting in an ischemic-type atrophy of segments II and III. However, due to a massive hypertrophy of the caudate lobe following PVE of liver segments IV-VIII, subsequent extended right hepatectomy with intraoperative thrombectomy of segments II and III was made possible. To our knowledge this is the first case in which an extended right hepatectomy for a liver malignancy, in the presence of atrophic left lateral section, was made possible by a massive PVE-associated hypertrophy of the caudate lobe.

Neuroprotective effect of pressure-oriented flow regulation and pH-stat management in selective antegrade brain perfusion during total aortic arch repair.

PubMed

Ito, Hisato; Mizumoto, Toru; Sawada, Yasuhiro; Fujinaga, Kazuya; Tempaku, Hironori; Yamamoto, Yasunori; Tsutsui, Katsuhiro; Shimpo, Hideto

2017-10-01

The aim of this study was to assess the safety and effectiveness of our selective antegrade brain perfusion (SABP) strategy, which is characterized by moderate hypothermic and low-pressure management under pH-stat using a completely closed cardiopulmonary bypass circuit with a single centrifugal pump. Forty-nine consecutive patients (median age, 74) underwent total aortic arch replacement using a 4-branched graft. SABP was conducted with individual cannulation in all arch vessels. The SABP flow rate was monitored, and the flow rates of each arch vessel were also measured in patients with available data. One patient died of cerebral infarction, and 7 had transient neurological deficits without apparent findings on postoperative imaging studies and without residual sequels at hospital discharge. The operation, cardiopulmonary bypass, cardiac arrest, circulatory arrest and SABP times were 327 min (interquartile range, 292-381), 211 (184-247), 107 (84.8-138.3), 54.0 (48-68) and 137 (114-158), respectively. The total flow of the SABP was 18.1 ml/kg/min (15.7-20.9). The flow rates of the brachiocephalic, the left carotid and the left subclavian arteries were 9.5 ml/kg/min (7.7-11.5), 4.2 (2.8-5.7) and 4.5 (3.7-5.5), respectively. Only the flow rate of the brachiocephalic artery was significantly correlated with the total SABP flow rate (Spearman rank correlation coefficient, r = 0.58, P < 0.01). The moderate hypothermic, high-flow, low-pressure SABP strategy with pH-stat management can be applied in adult aortic surgery; however, the feasibility and effectiveness of this concept need further evaluation in a prospective controlled study. © The Author 2017. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

A Study Demonstrating the Quantitative Relationship Between Internal Thoracic Artery Length and Free Flow.

PubMed

Gode, Safa; Sen, Onur; Kadirogulları, Ersin; Reyhancan, Adem; Kyaruzi, Mugisha; Satılmısoglu, Muhammet Hulusi; Erkanlı, Korhan

2017-08-09

The left internal thoracic artery (LITA) is the most commonly used arterial bypass conduit in coronary artery bypass graft (CABG) patients and inadequate LITA flow can result in an increase in morbidity and mortality. In this study, we evaluated the effect of excision of the distal spasmodic segment of the LITA on the free flow in CABG patients. This study consisted of 47 patients who underwent elective CABG performed with or without other cardiac surgery, between July 2015 and December 2015. Excised LITA length was shorter than 15mm in group 1, between 15mm and 30mm in group 2 and longer than 30mm in group 3. Left ITA free flow was measured for 60seconds into a container before and after the distal LITA excision. The inter-measurement differences were calculated for the three groups. Thereafter, the comparison was performed in terms of free flow difference amongst the three groups. The mean difference of LITA free flow was 27.6±22.7ml/minute in group 1, 35.4±26.7ml/minute in group 2, and 52.6±26.1ml/minute in group 3. There were significant differences in terms of free flow difference between the groups (p=0.008). Also, differences were statistically significant in group 1 versus group 3 (p=0.003) and group 2 versus group 3 (p=0.038) in the intergroup comparisons. The distal part of the LITA has more spasmodic potential than other segments. This spasm may result in low flow of LITA grafts. Therefore, an as long as possible excision of the distal LITA segment may be required to avoid the spasmodic effect. Copyright © 2017 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.

4D flow MRI assessment of right atrial flow patterns in the normal heart – influence of caval vein arrangement and implications for the patent foramen ovale

PubMed Central

Parikh, Jehill D.; Kakarla, Jayant; Keavney, Bernard; O’Sullivan, John J.; Ford, Gary A.; Blamire, Andrew M.; Hollingsworth, Kieren G.

2017-01-01

Aim To investigate atrial flow patterns in the normal adult heart, to explore whether caval vein arrangement and patency of the foramen ovale (PFO) may be associated with flow pattern. Materials and Methods Time-resolved, three-dimensional velocity encoded magnetic resonance imaging (4D flow) was employed to assess atrial flow patterns in thirteen healthy subjects (6 male, 40 years, range 25–50) and thirteen subjects (6 male, 40 years, range 21–50) with cryptogenic stroke and patent foramen ovale (CS-PFO). Right atrial flow was defined as vortical, helico-vortical, helical and multiple vortices. Time-averaged and peak systolic and diastolic flows in the caval and pulmonary veins and their anatomical arrangement were compared. Results A spectrum of right atrial flow was observed across the four defined categories. The right atrial flow patterns were strongly associated with the relative position of the caval veins. Right atrial flow patterns other than vortical were more common (p = 0.015) and the separation between the superior and inferior vena cava greater (10±5mm versus 3±3mm, p = 0.002) in the CS-PFO group. In the left atrium all subjects except one had counter-clockwise vortical flow. Vortex size varied and was associated with left lower pulmonary vein flow (systolic r = 0.61, p = 0.001, diastolic r = 0.63 p = 0.002). A diastolic vortex was less common and time-averaged left atrial velocity was greater in the CS-PFO group (17±2cm/sec versus 15±1, p = 0.048). One CS-PFO subject demonstrated vortical retrograde flow in the descending aortic arch; all other subjects had laminar descending aortic flow. Conclusion Right atrial flow patterns in the normal heart are heterogeneous and are associated with the relative position of the caval veins. Patterns, other than ‘typical’ vortical flow, are more prevalent in the right atrium of those with cryptogenic stroke in the context of PFO. Left atrial flow patterns are more homogenous in normal hearts and show a relationship with flow arising from the left pulmonary veins. PMID:28282389

10. WHITNEY'S FLUME AND VIEW OF THE CONFLUENCE OF TONTO ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

10. WHITNEY'S FLUME AND VIEW OF THE CONFLUENCE OF TONTO CREEK AND THE SALT RIVER. AREA SHOWN IS PRESENTLY UNDER WATER. TONTO CREEK FLOWS FROM BACKGROUND CENTER TO LEFT, AND THE SALT RIVER FLOWS FROM RIGHT TO LEFT IN THE PHOTO. DAM IS LOCATED OFF THE PHOTO TO THE LEFT Photographer: Walter J. Lubken, March 3, 1906 - Roosevelt Power Canal & Diversion Dam, Parallels Salt River, Roosevelt, Gila County, AZ

Observation of cardiogenic flow oscillations in healthy subjects with hyperpolarized 3He MRI

PubMed Central

Collier, Guilhem J.; Marshall, Helen; Rao, Madhwesha; Stewart, Neil J.; Capener, David

2015-01-01

Recently, dynamic MRI of hyperpolarized 3He during inhalation revealed an alternation of the image intensity between left and right lungs with a cardiac origin (Sun Y, Butler JP, Ferrigno M, Albert MS, Loring SH. Respir Physiol Neurobiol 185: 468–471, 2013). This effect is investigated further using dynamic and phase-contrast flow MRI with inhaled 3He during slow inhalations (flow rate ∼100 ml/s) to elucidate airflow dynamics in the main lobes in six healthy subjects. The ventilation MR signal and gas inflow in the left lower lobe (LLL) of the lungs were found to oscillate clearly at the cardiac frequency in all subjects, whereas the MR signals in the other parts of the lungs had a similar oscillatory behavior but were smaller in magnitude and in anti-phase to the signal in the left lower lung. The airflow in the main bronchi showed periodic oscillations at the frequency of the cardiac cycle. In four of the subjects, backflows were observed for a short period of time of the cardiac cycle, demonstrating a pendelluft effect at the carina bifurcation between the left and right lungs. Additional 1H structural MR images of the lung volume and synchronized ECG recording revealed that maximum inspiratory flow rates in the LLL of the lungs occurred during systole when the corresponding left lung volume increased, whereas the opposite effect was observed during diastole, with gas flow redirected to the other parts of the lung. In conclusion, cardiogenic flow oscillations have a significant effect on regional gas flow and distribution within the lungs. PMID:26338461

Intra-aortic balloon pumping in acute mitral regurgitation reduces aortic impedance and regurgitant fraction.

PubMed

Dekker, André L A J; Reesink, Koen D; van der Veen, Frederik H; van Ommen, G Vincent A; Geskes, Gijs G; Soemers, A Cecilia M; Maessen, Jos G

2003-04-01

Acute mitral regurgitation (MR) is present in 10% of patients presenting with cardiogenic shock. To stabilize these patients, intra-aortic balloon pumping (IABP) is recommended, but the mechanism of IABP support in these patients is unknown. This animal study was designed to describe the hemodynamic effect of intra-aortic balloon pumping during cardiogenic shock induced by acute MR. In eight calves, left ventricular pressure-volume loops, aortic and left atrial pressure, and aortic, carotid artery, and coronary blood flow were recorded. Acute MR (range 36%-79%) was created by placing a metal cage in the mitral valve. Hemodynamic data was obtained at control, during acute MR, and during acute MR with 1:1 IABP support. Acute MR caused a decrease in cardiac output (-32%, P = 0.018), blood pressure, and carotid artery flow, whereas left ventricular output (+127%, P = 0.018), end-diastolic volume, and left atrial pressure all significantly increased. Stroke work, ejection fraction, and coronary blood flow were not significantly changed, and no signs of ischemia were seen on the ECG. The IABP raised average cardiac output by 31% (P = 0.012) and significantly raised blood pressure and flow to the brain while decreasing systemic vascular resistance. Left ventricular function and mean coronary blood flow did not change, but diastolic coronary flow became more important as shown by the increase in diastolic fraction from 64% to 95%. (P = 0.028). Average MR dropped by 7.5% (P = 0.025). In conclusion, application of the IABP during acute MR lowers aortic impedance, resulting in less MR and more output toward the aorta without changing left ventricular function.

Analysis of transit time flow of the right internal thoracic artery anastomosed to the left anterior descending artery compared to the left internal thoracic artery

PubMed Central

Milani, Rodrigo; de Moraes, Daniela; Sanches, Aline; Jardim, Rodrigo; Lumikoski, Thais; Miotto, Gabriela; Santana, Vitor Hugo; Brofman, Paulo Roberto

2014-01-01

Introduction We evaluated with transit time flow the performance of the right and left thoracic arteries when used as a graft for the left anterior descending artery. Methods Fifty patients undergoing surgery for myocardial revascularization without cardiopulmonary bypass were divided into two groups. In group A patients received graft of right internal mammary artery to the anterior interventricular branch. In group B patients received graft of left internal mammary artery to the same branch. At the end of the operation the flow was assessed by measuring transit time. Results In group A, mean age was 60.6±9.49 years. The average height and weight of the group was 80.4±10.32 kg and 169.2±6.86 cm. The average number of grafts per patient in this group was 3.28±1.49. The mean flow and distal resistance obtained in right internal thoracic artery was 42.1±23.4 ml/min and 2.8±0.9 respectively. In group B, the mean age was 59.8±9.7 years. The average height and weight of this group was 77.7±14.22 kg and 166.0±8.2 cm. The average number of grafts per patient in this group was 3.08 ±0.82. The mean flow and distal resistance observed in this group was 34.2±19.1 ml/min and 2.0±0.7. There were no deaths in this series. Conclusion Right internal mammary artery presented a similar behavior to left internal mammary artery when anastomosed to the anterior interventricular branch of the left coronary artery. There was no statistical difference between the measured flow obtained between both arteries. PMID:25140463

Research on traffic flow characteristics at signal intersection

NASA Astrophysics Data System (ADS)

Zeng, Jun-Wei; Yu, Sen-Bin; Qian, Yong-Sheng; Wei, Xu-Ting; Feng, Xiao; Wang, Hui

2017-09-01

Based on the cautious driving behavior and the principle of the vehicles at left-side having priority to pass in the intersection, a two-dimensional cellular automata model for planar signalized intersection (NS-STCA) is established. The different turning vehicles are regarded as the research objects and the effect of the left-turn probability, signal cycle, vehicle flow density on traffic flow at the intersection is investigated.

Regression of left ventricular hypertrophy provides an additive physiological benefit following treatment of aortic stenosis: insights from serial coronary wave-intensity analysis.

PubMed

Broyd, Christopher J; Rigo, Fausto; Nijjer, Sukhjinder; Sen, Sayan; Petraco, Ricardo; Al-Lamee, Rasha; Foin, Nicolas; Chukwuemeka, Andrew; Anderson, Jon; Parker, Jessica; Malik, Iqbal S; Mikhail, Ghada W; Francis, Darrel P; Parker, Kim; Hughes, Alun D; Mayet, Jamil; Davies, Justin E

2018-06-23

Severe aortic stenosis frequently involves the development of left ventricular hypertrophy (LVH) creating a dichotomous hemodynamic state within the coronary circulation. Whilst the increased force of ventricular contraction enhances its resultant relaxation and thus increases the distal diastolic coronary 'suction' force, the presence of LVH has a potentially opposing effect on ventricular-coronary interplay. The aim of this study was to use non-invasive coronary wave-intensity analysis (WIA) to separate and measure the sequential effects of outflow-tract obstruction relief and then left ventricular hypertrophy (LVH) regression following intervention for aortic stenosis. 15 patients with unobstructed coronary arteries undergoing aortic valve intervention (11 SAVR, 4 TAVI) were successfully assessed before and after intervention, and at 6- and 12-months post-procedure. Coronary WIA was constructed from simultaneously acquired coronary flow from transthoracic echo and pressure from an oscillometric brachial-cuff system. Immediately following intervention, a decline in the BDW was noted (9.7±5.7 vs 5.1±3.6 x10 3 Wm -2 s -1 , p<0.01). Over 12 months, LV mass-index fell from 114±19 to 82±17 kg/m 2 . Accompanying this, the BDW fraction increased to 32.8±7.2% (p=0.01 vs post-procedure) and to 34.7±6.7% at 12 months (p<0.001 vs post-procedure). In aortic stenosis, both the outflow-tract gradient and the presence of LVH impact significantly on coronary haemodynamics that cannot be appreciated by examining resting coronary flow rates alone. An immediate change in coronary wave-intensity occurs following intervention with further effects appreciable with hypertrophy regression. The improvement in prognosis with treatment is likely to be attributable to both features. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Numerical simulation of left ventricular assist device implantations: comparing the ascending and the descending aorta cannulations.

PubMed

Bonnemain, Jean; Malossi, A Cristiano I; Lesinigo, Matteo; Deparis, Simone; Quarteroni, Alfio; von Segesser, Ludwig K

2013-10-01

In this work we present numerical simulations of continuous flow left ventricle assist device implantation with the aim of comparing difference in flow rates and pressure patterns depending on the location of the anastomosis and the rotational speed of the device. Despite the fact that the descending aorta anastomosis approach is less invasive, since it does not require a sternotomy and a cardiopulmonary bypass, its benefits are still controversial. Moreover, the device rotational speed should be correctly chosen to avoid anomalous flow rates and pressure distribution in specific location of the cardiovascular tree. With the aim of assessing the differences between these two approaches and device rotational speed in terms of flow rate and pressure waveforms, we set up numerical simulations of network of one-dimensional models where we account for the presence of an outflow cannula anastomosed to different locations of the aorta. Then, we use the resulting network to compare the results of the two different cannulations for several stages of heart failure and different rotational speed of the device. The inflow boundary data for the heart and the cannulas are obtained from a lumped parameters model of the entire circulatory system with an assist device, which is validated with clinical data. The results show that ascending and descending aorta cannulations lead to similar waveforms and mean flow rate in all the considered cases. Moreover, regardless of the anastomosis region, the rotational speed of the device has an important impact on wave profiles; this effect is more pronounced at high RPM. Copyright © 2013 IPEM. Published by Elsevier Ltd. All rights reserved.

Renal and femoral venous blood flows are regulated by different mechanisms dependent on α-adrenergic receptor subtypes and nitric oxide in anesthetized rats.

PubMed

Fioretti, Alexandre C; Ogihara, Cristiana A; Cafarchio, Eduardo M; Venancio, Daniel P; de Almeida, Roberto Lopes; Antonio, Bruno B; Sato, Monica A

2017-12-01

Venous and arterial walls are responsive to sympathetic system and circulating substances, nevertheless, very few is known about the venous blood flow regulation simultaneously to arterial vascular beds. In this study, we compared the venous and arterial blood flow regulation in visceral and muscular beds upon injection of different doses of vasoactive drugs which act in arterial vascular beds. Anesthetized adult male Wistar rats underwent to right femoral artery and vein cannulation for hemodynamic recordings and infusion of drugs. Doppler flow probes were placed around the left renal artery and vein, and left femoral artery and vein to evaluate the changes in flood flow. Phenylephrine (PHE) injection (α 1 -adrenergic receptor agonist) elicited vasoconstriction in all arteries and veins. Intravenous prazosin (PZS) (1mg/kg, α 1 -adrenergic receptor blocker) caused renal artery vasodilation, but not in the other beds. Vasoconstrictor effect of PHE was abolished by PZS in all vascular beds, except in femoral vein. Phentolamine (PTL) injection (1mg/kg, α 1 /α 2 -adrenergic receptor blocker) produced renal artery vasodilation with no change in other beds. After PTL, the vasoconstriction evoked by PHE was abolished in all vascular beds. Sodium Nitroprusside (SNP), a nitric oxide donor, elicited vasodilation in all beds, and after PTL but not post PZS injection, SNP enhanced the vasodilatory effect in femoral vein. Our findings suggest that the vasoconstriction in renal and femoral veins is mediated by different subtypes of α-adrenoceptors. The nitric oxide-dependent vasodilation in femoral vein enhances when α 2 -adrenoceptors are not under stimulation, but not in the other vascular beds investigated. Copyright © 2017 Elsevier Inc. All rights reserved.

Diastolic heart failure associated with hemangiosarcoma infiltrating left ventricular walls in a dog

PubMed Central

Osuga, Tatsuyuki; Nakamura, Kensuke; Morita, Tomoya; Kagawa, Yumiko; Ohta, Hiroshi; Takiguchi, Mitsuyoshi

2017-01-01

A 9-year-old Shetland sheepdog was diagnosed with cardiogenic pulmonary edema. Echocardiography revealed focally thickened left ventricular free wall and interventricular septum and left atrial dilation. Left ventricular systolic function was preserved. Doppler echocardiography of transmitral flow indicated restrictive left ventricular filling. Cardiac histopathology demonstrated hemangiosarcoma infiltrating the left ventricular walls. PMID:29089652

Diastolic heart failure associated with hemangiosarcoma infiltrating left ventricular walls in a dog.

PubMed

Osuga, Tatsuyuki; Nakamura, Kensuke; Morita, Tomoya; Kagawa, Yumiko; Ohta, Hiroshi; Takiguchi, Mitsuyoshi

2017-11-01

A 9-year-old Shetland sheepdog was diagnosed with cardiogenic pulmonary edema. Echocardiography revealed focally thickened left ventricular free wall and interventricular septum and left atrial dilation. Left ventricular systolic function was preserved. Doppler echocardiography of transmitral flow indicated restrictive left ventricular filling. Cardiac histopathology demonstrated hemangiosarcoma infiltrating the left ventricular walls.

Left atrial enlargement increases the risk of major adverse cardiac events independent of coronary vasodilator capacity.

PubMed

Koh, Angela S; Murthy, Venkatesh L; Sitek, Arkadiusz; Gayed, Peter; Bruyere, John; Wu, Justina; Di Carli, Marcelo F; Dorbala, Sharmila

2015-09-01

Longstanding uncontrolled atherogenic risk factors may contribute to left atrial (LA) hypertension, LA enlargement (LAE) and coronary vascular dysfunction. Together they may better identify risk of major adverse cardiac events (MACE). The aim of this study was to test the hypothesis that chronic LA hypertension as assessed by LAE modifies the relationship between coronary vascular function and MACE. In 508 unselected subjects with a normal clinical (82)Rb PET/CT, ejection fraction ≥40 %, no prior coronary artery disease, valve disease or atrial fibrillation, LAE was determined based on LA volumes estimated from the hybrid perfusion and CT transmission scan images and indexed to body surface area. Absolute myocardial blood flow and global coronary flow reserve (CFR) were calculated. Subjects were systematically followed-up for the primary end-point - MACE - a composite of all-cause death, myocardial infarction, hospitalization for heart failure, stroke, coronary artery disease progression or revascularization. During a median follow-up of 862 days, 65 of the subjects experienced a composite event. Compared with subjects with normal LA size, subjects with LAE showed significantly lower CFR (2.25 ± 0.83 vs. 1.95 ± 0.80, p = 0.01). LAE independently and incrementally predicted MACE even after accounting for clinical risk factors, medication use, stress left ventricular ejection fraction, stress left ventricular end-diastolic volume index and CFR (chi-squared statistic increased from 30.9 to 48.3; p = 0.001). Among subjects with normal CFR, those with LAE had significantly worse event-free survival (risk adjusted HR 5.4, 95 % CI 2.3 - 12.8, p < 0.0001). LAE and reduced CFR are related but distinct cardiovascular adaptations to atherogenic risk factors. LAE is a risk marker for MACE independent of clinical factors and left ventricular volumes; individuals with LAE may be at risk of MACE despite normal coronary vascular function.

Estimation of myocardial flow reserve utilizing an ultrafast cardiac SPECT: Comparison with coronary angiography, fractional flow reserve, and the SYNTAX score.

PubMed

Miyagawa, Masao; Nishiyama, Yoshiko; Uetani, Teruyoshi; Ogimoto, Akiyoshi; Ikeda, Shuntaro; Ishimura, Hayato; Watanabe, Emiri; Tashiro, Rami; Tanabe, Yuki; Kido, Teruhito; Kurata, Akira; Mochizuki, Teruhito

2017-10-01

Quantitative assessment of myocardial flow reserve (MFR) by single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) is challenging but may facilitate evaluation of multi-vessel coronary artery disease (CAD). We enrolled 153 patients with suspected or known CAD, referred for pharmacological stress MPI. They underwent a 99m Tc-perfusion stress/rest SPECT with an ultrafast cadmium-zinc-telluride (CZT) camera. Dynamic data were acquired and time-activity curves fitted to a 1-tissue compartment analysis with input function. K1 was assigned for stress and rest data. The MFR index (MFRi) was calculated as K1 stress/K1 at-rest. The findings were validated by invasive coronary angiography in 69 consecutive patients. The global MFRi was 1.46 (1.16-1.76), 1.33 (1.12-1.54), and 1.18 (1.01-1.35), for 1-vessel disease (VD), 2-VD, and 3-VD, respectively. In the 3-VD, global MFRi was lower than that in 0-VD (1.63 [1.22-2.04], P<0.0001) and 1-VD (P=0.003). Multivariate logistic regression analysis for 3-VD showed significant associations with smoking history (odds ratio [OR]: 4.4 [0.4-8.4]), left ventricular ejection fraction (OR: 61.6 [57.5-66.0]), and global MFRi (OR: 119.6 [111.5-127.7], P=0.002). A cut-off value of 1.3 yielded 93.3% sensitivity and 75.9% specificity for diagnosing 3-VD. Fractional flow reserve positively correlated with regional MFRi (r=0.62, P=0.008), and the SYNTAX score correlated negatively with global MFRi (r=0.567, P=0.0003). We developed and validated a clinically available method for MFR quantification by dynamic 99m Tc-perfusion SPECT utilizing a CZT camera, which improves the detectability of multi-vessel CAD. Copyright © 2017 Elsevier B.V. All rights reserved.

Spectral Doppler interrogation of the patent foramen ovale-a window to left heart hemodynamics.

PubMed

Fadel, Bahaa M; Husain, Aysha; Bakarman, Hatem; Dahdouh, Ziad; Salvo, Giovanni Di; Mohty, Dania

2015-02-01

Spectral Doppler interrogation of flow across a patent foramen ovale (PFO) allows recording of the instantaneous pressure gradient between left and right atrium (RA). The assessment of RA pressure using the size and collapsibility of the inferior vena cava would thus allow estimation of left atrial (LA) pressure. In this article, we illustrate the value of spectral Doppler interrogation of flow across the PFO by transthoracic echocardiography as a novel and simple tool for the assessment of LA pressure and left cardiac hemodynamics in addition to the conventional noninvasive parameters. © 2014, Wiley Periodicals, Inc.

Doppler echocardiographic evaluation of midventricular obstruction in cats with hypertrophic cardiomyopathy.

PubMed

MacLea, H B; Boon, J A; Bright, J M

2013-01-01

Hypertrophic cardiomyopathy (HCM) is heterogeneous in both people and cats, with variability in the distribution of hypertrophy, hemodynamic characteristics, and Doppler echocardiographic findings. To document the Doppler echocardiographic characteristics of midventricular obstruction in some cats with HCM. Eight cats with hypertrophic cardiomyopathy. Retrospective case series. The medical records of cats presenting to the cardiology service at Colorado State University between February 2009 and January 2012 were reviewed. All cats had a physical examination; Doppler systolic blood pressure measurement; and transthoracic two-dimensional (2D), M-mode, and Doppler echocardiography were performed. A more thorough evaluation of the echocardiographic images and measurements was performed. Cats included in this study had echocardiograms of adequate quality to confirm the diagnosis of midventricular obstruction by documentation of left midventricular concentric hypertrophy; a midventricular turbulent Doppler color flow pattern; and high velocity, late-peaking flow at the area of turbulence. Cats with evidence of systemic hypertension defined as a systolic Doppler blood pressure of greater than 170 mmHg were excluded. All 8 cats had left ventricular hypertrophy at the level of the papillary muscles; left, midventricular hypertrophy; and in 4/8 cats there was apical hypertrophy or basilar hypertrophy of the interventricular septum. Color flow Doppler revealed turbulent flow in 8/8 cats and spectral Doppler (continuous and pulsed wave) revealed increased flow velocities and late-peaking flow profiles at the level of the left midventricle. Two of 8 cats had a bifid midventricular flow profile in which there was a midsystolic decline in left ventricular velocities with elevated velocities extending into early diastole. The peak left ventricular outflow velocity in all 8 cats was normal. A variant of HCM characterized by hypertrophy at the level of the papillary muscles with midventricular obstruction is present in some cats. Recognition of this variant of feline HCM allows identification of HCM in cats with murmurs where the more classic features of HCM are not present. Copyright © 2013 by the American College of Veterinary Internal Medicine.

Aortic valve bypass surgery in severe aortic valve stenosis: Insights from cardiac and brain magnetic resonance imaging.

PubMed

Mantini, Cesare; Caulo, Massimo; Marinelli, Daniele; Chiacchiaretta, Piero; Tartaro, Armando; Cotroneo, Antonio Raffaele; Di Giammarco, Gabriele

2018-04-13

To investigate and describe the distribution of aortic and cerebral blood flow (CBF) in patients with severe valvular aortic stenosis (AS) before and after aortic valve bypass (AVB) surgery. We enrolled 10 consecutive patients who underwent AVB surgery for severe AS. Cardiovascular magnetic resonance imaging (CMR) and brain magnetic resonance imaging were performed as baseline before surgery and twice after surgery. Quantitative flow measurements were obtained using 1.5-T magnetic resonance imaging (MRI) scanner phase-contrast images of the ascending aorta, descending thoracic aorta (3 cm proximally and distally from the conduit-to-aorta anastomosis), and ventricular outflow portion of the conduit. The evaluation of CBF was performed using 3.0-T MRI scanner arterial spin labeling (ASL) through sequences acquired at the gray matter, dorsal default-mode network, and sensorimotor levels. Conduit flow, expressed as the percentage of total antegrade flow through the conduit, was 63.5 ± 8% and 67.8 ± 7% on early and mid-term postoperative CMR, respectively (P < .05). Retrograde perfusion from the level of the conduit insertion in the descending thoracic aorta toward the aortic arch accounted for 6.9% of total cardiac output and 11% of total conduit flow. We did not observe any significant reduction in left ventricular stroke volume at postoperative evaluation compared with preoperative evaluation (P = .435). No differences were observed between preoperative and postoperative CBF at the gray matter, dorsal default-mode network, and sensorimotor levels (P = .394). After AVB surgery in patients with severe AS, cardiac output is split between the native left ventricular outflow tract and the apico-aortic bypass, with two-thirds of the total antegrade flow passing through the latter and one-third passing through the former. In our experience, CBF assessment confirms that the flow redistribution does not jeopardize cerebral blood supply. Copyright © 2018 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

Left Ventricular Assist Device Design Reduces von Willebrand Factor Degradation: A Comparative Study Between the HeartMate II and the EVAHEART Left Ventricular Assist System.

PubMed

Bartoli, Carlo R; Kang, Jooeun; Zhang, David; Howard, Jessica; Acker, Michael; Atluri, Pavan; Motomura, Tadashi

2017-04-01

Supraphysiologic shear stress from continuous-flow left ventricular assist devices (LVADs) accelerates von Willebrand factor (vWF) degradation and predisposes patients to nonsurgical bleeding. It is unknown whether unique design characteristics of LVADs differentially affect vWF degradation. We tested the hypothesis that the centrifugal-flow EVAHEART (Evaheart, Houston, TX) left ventricular assist system (LVAS), which was designed to minimize shear stress (low operational revolutions per minute [rpm], larger flow gaps, low shear stress, flat H-Q curve), reduced vWF degradation versus the axial-flow HeartMate II (Thoratec, Pleasanton, CA) LVAD. Whole human blood was obtained from volunteer donors (n = 22). Blood was circulated for 12 hours in mock circulatory loops through a HeartMate II (n = 10; 11,400 rpm, 6.3 ± 0.8 L/min, 76 ± 2 mm Hg) or an EVAHEART LVAS (n = 12; 2,300 rpm, 5.7 ± 0.1 L/min, 80 ± 1 mm Hg). vWF degradation was characterized with electrophoresis and immunoblotting for large vWF multimers and 11 vWF degradation fragments. The HeartMate II eliminated large vWF multimers and significantly (p < 0.05) increased 10 of 11 vWF degradation fragments at 6 and 12 hours. The increase was approximately 2.0-fold at 6 hours and 2.2-fold at 12 hours. In contrast, the EVAHEART LVAS modestly reduced large vWF multimers and significantly increased 5 of 11 and 8 of 11 vWF degradation fragments at 6 and 12 hours, respectively. The increase was approximately 1.5-fold at 6 hours and 1.7-fold at 12 hours. The EVAHEART LVAS caused significantly less degradation (p < 0.01) than the HeartMate II of the 140 kDa vWF fragment (cleavage product of ADAMTS-13, the vWF protease). The EVAHEART LVAS caused significantly less vWF degradation than the HeartMate II in a mock circulatory loop with whole human blood. LVAD design features may minimize vWF degradation. These data may inform the design and operation of next-generation LVADs to minimize blood trauma. Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Distribution of intrarenal blood flow consequent to left atrial balloon inflation.

PubMed

Passmore, J C; Stremel, R W; Hock, C E; Allen, R L; Bradford, W B

1985-01-01

The effects of inflation of a balloon within, and consequent distension of, the left atrium (LABI, left atrial balloon inflation) on total renal blood flow (RBF) and intrarenal blood flow distribution were measured and compared to values obtained from another group of dogs that were hemorrhaged (HEM) to the same level of hypotension as that produced by LABI, a mean systemic arterial pressure of 88 mm Hg. Kidney wt/kg, RBF/kg body wt, and urine flow were markedly reduced during the hemorrhage period in the HEM group when compared to values obtained during the experimental period for the LABI group. Data from the freeze-dissection (133Xe) analysis revealed that the percentage distribution of blood flow as renal outer cortical (OC) blood flow was less (26%) in the HEM group than in the LABI group (50%), this latter value being very similar to that of control dogs that experienced no hypotension (49%). LABI better maintains OC blood flow and urine flow when compared to HEM at the same systemic blood pressure, suggesting a role for cardiopulmonary receptors in reflex sympathetic control of renal blood flow distribution during hypotension.

A quantitative comparison of transesophageal and epicardial color Doppler echocardiography in the intraoperative assessment of mitral regurgitation.

PubMed

Kleinman, J P; Czer, L S; DeRobertis, M; Chaux, A; Maurer, G

1989-11-15

Epicardial and transesophageal color Doppler echocardiography are both widely used for the intraoperative assessment of mitral regurgitation (MR); however, it has not been established whether grading of regurgitation is comparable when evaluated by these 2 techniques. MR jet size was quantitatively compared in 29 hemodynamically and temporally matched open-chest epicardial and transesophageal color Doppler echocardiography studies from 22 patients (18 with native and 4 with porcine mitral valves) scheduled to undergo mitral valve repair or replacement. Jet area, jet length and left atrial area were analyzed. Comparison of jet area measurements as assessed by epicardial and transesophageal color flow mapping revealed an excellent correlation between the techniques (r = 0.95, p less than 0.001). Epicardial and transesophageal jet length measurements were also similar (r = 0.77, p less than 0.001). Left atrial area could not be measured in 18 transesophageal studies (62%) due to foreshortening, and in 5 epicardial studies (17%) due to poor image resolution. Acoustic interference with left atrial and color flow mapping signals was noted in all patients with mitral valve prostheses when imaged by epicardial echocardiography, but this did not occur with transesophageal imaging. Thus, in patients undergoing valve repair or replacement, transesophageal and epicardial color flow mapping provide similar quantitative assessment of MR jet size. Jet area to left atrial area ratios have limited applicability in transesophageal color flow mapping, due to foreshortening of the left atrial borders in transesophageal views. Transesophageal color flow mapping may be especially useful in assessing dysfunctional mitral prostheses due to the lack of left atrial acoustic interference.

'Left behind' but not left alone: parental migration & the psychosocial health of children in Moldova.

PubMed

Vanore, Michaella; Mazzucato, Valentina; Siegel, Melissa

2015-05-01

In Moldova, large-scale and rapidly feminised migration flows have inspired a wave of qualitative reports on children "left behind". Despite this recent interest, few studies have empirically evaluated the effects of parental migration on the psychosocial health of such children. Using data collected from a nationally-representative household survey conducted in Moldova between September 2011 and February 2012, this paper analyses the psychosocial health outcomes of children of migrant parents by comparing them with children without migrant parents (n = 1979). Child psychosocial health is measured through caregiver-reported Strengths and Difficulties Questionnaire (SDQ) scores. Multivariate regression analyses show that parental migration seldom corresponds to worse emotional symptoms outcomes but does correspond to increased conduct problems. Separate analyses for male and female children show significant gendered differences. The results partially contest the negative results that have been the subject of qualitative reports and, in particular, demonstrate that the migration of mothers infrequently results in worse psychosocial outcomes for children-contrary to what has been assumed in the discourse about parental migration in Moldova. Copyright © 2014 Elsevier Ltd. All rights reserved.

Complex blood flow patterns in an idealized left ventricle: A numerical study

NASA Astrophysics Data System (ADS)

Tagliabue, Anna; Dedè, Luca; Quarteroni, Alfio

2017-09-01

In this paper, we study the blood flow dynamics in a three-dimensional (3D) idealized left ventricle of the human heart whose deformation is driven by muscle contraction and relaxation in coordination with the action of the mitral and aortic valves. We propose a simplified but realistic mathematical treatment of the valves function based on mixed time-varying boundary conditions (BCs) for the Navier-Stokes equations modeling the flow. These switchings in time BCs, from natural to essential and vice versa, model either the open or the closed configurations of the valves. At the numerical level, these BCs are enforced by means of the extended Nitsche's method (Tagliabue et al., Int. J. Numer. Methods Fluids, 2017). Numerical results for the 3D idealized left ventricle obtained by means of Isogeometric Analysis are presented, discussed in terms of both instantaneous and phase-averaged quantities of interest and validated against those available in the literature, both experimental and computational. The complex blood flow patterns are analysed to describe the characteristic fluid properties, to show the transitional nature of the flow, and to highlight its main features inside the left ventricle. The sensitivity of the intraventricular flow patterns to the mitral valve properties is also investigated.

Histogram based analysis of lung perfusion of children after congenital diaphragmatic hernia repair.

PubMed

Kassner, Nora; Weis, Meike; Zahn, Katrin; Schaible, Thomas; Schoenberg, Stefan O; Schad, Lothar R; Zöllner, Frank G

2018-05-01

To investigate a histogram based approach to characterize the distribution of perfusion in the whole left and right lung by descriptive statistics and to show how histograms could be used to visually explore perfusion defects in two year old children after Congenital Diaphragmatic Hernia (CDH) repair. 28 children (age of 24.2±1.7months; all left sided hernia; 9 after extracorporeal membrane oxygenation therapy) underwent quantitative DCE-MRI of the lung. Segmentations of left and right lung were manually drawn to mask the calculated pulmonary blood flow maps and then to derive histograms for each lung side. Individual and group wise analysis of histograms of left and right lung was performed. Ipsilateral and contralateral lung show significant difference in shape and descriptive statistics derived from the histogram (Wilcoxon signed-rank test, p<0.05) on group wise and individual level. Subgroup analysis (patients with vs without ECMO therapy) showed no significant differences using histogram derived parameters. Histogram analysis can be a valuable tool to characterize and visualize whole lung perfusion of children after CDH repair. It allows for several possibilities to analyze the data, either describing the perfusion differences between the right and left lung but also to explore and visualize localized perfusion patterns in the 3D lung volume. Subgroup analysis will be possible given sufficient sample sizes. Copyright © 2017 Elsevier Inc. All rights reserved.

Postoperative pulmonary hypertensive crisis caused by inverted left atrial appendage after cardiopulmonary bypass surgery for congenital heart disease in a neonate.

PubMed

Zhao, Qifeng; Hu, Xingti

2013-09-01

Postoperative pulmonary hypertensive crisis (PHC) caused by an inverted left atrial appendage (ILAA) is a rare complication following cardiac surgery. We present a case of 23 day-old male infant who developed postoperative PHC attacks after undergoing cardiopulmonary bypass (CPB) surgery for repair of the coactation of aorta. A hyperechogenic left atrial mass was detected via bedside transthoracic echocardiography (TTE), which was identified as an ILAA and corrected following repeat surgery. In this case, both the negative pressure in vent catheter and the long left atrial appendage (LAA) with a narrow base led to an irreversible ILAA. As in this neonate, ILAA had significant influence on the left atrial volume and caused PHC since the ILAA was located on the mitral valve orifice and interfered with the blood flow through the valve. Therefore, we recommend that the vent catheter should be turned off before removing to avoid this potential complication. Additionally, LAA should be carefully inspected after CPB surgery, and intra-operative and post-operative transoesophageal echocardiography (TEE) should be performed to detect ILAA intraoperatively so as to avoid the reoperation. When an ILAA is diagnosed postoperatively, whether conservative treatment or surgery will depend on the balance of benefit and risk for a particular patient. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

Acute Hearing Loss Caused by Decreasing Anterior Inferior Cerebellar Arterial Perfusion in a Patient with Vertebral Artery Stenosis.

PubMed

Fukuda, Rintaro; Miyamoto, Nobukazu; Hayashida, Arisa; Ueno, Yuji; Yamashiro, Kazuo; Tanaka, Ryota; Hattori, Nobutaka

2017-06-01

We report a case of bilateral hearing loss caused by decreased vascular flow in the anterior inferior cerebellar artery (AICA) territory. A 74-year-old man who experienced right hearing loss 5 months ago presented with bilateral deafness and right cerebellar ataxia; however, no ischemic lesion was detected in the bilateral AICA area. After stroke treatment, hearing loss was improved. One month later, we obtained blood flow improvement in the left AICA territory on single-photon-emission computed tomography and vertebral artery stenosis on magnetic resonance angiography. Therefore, clinicians should recognize that bilateral hearing loss may be related to stroke in the vertebrobasilar artery area. Copyright © 2017 National Stroke Association. Published by Elsevier Inc. All rights reserved.

A novel mouse model of high flow-induced pulmonary hypertension-surgically induced by right pulmonary artery ligation.

PubMed

Zhang, Anchen; Wang, Hongfei; Wang, Shengwei; Huang, Xiaofan; Ye, Ping; Du, Xinling; Xia, Jiahong

2017-02-01

This study sought to establish a new model of high-flow pulmonary hypertension (PH) in mice. This model may be useful for studies seeking to reduce the pulmonary vascular resistance and delay the development of PH caused by congenital heart disease. The right pulmonary artery was ligated via a right posterolateral thoracotomy. Pulmonary hemodynamics was evaluated by right heart catheterization immediately after ligation and at 2, 4, 8, and 12 wk postoperatively. The right ventricle (RV) and the left ventricle (LV) with septum (S) were weighed to calculate the RV/(LV + S) ratio as an index of right ventricular hypertrophy. Morphologic changes in the left lungs were analyzed, and percentages of muscularized pulmonary vessels were assessed by hematoxylin and eosin, elastica van Gieson and alpha-smooth muscle actin staining. All the study data were compared with data from a model of PH generated by hypoxic stimulation. A pulmonary hypertensive state was successfully induced by 2 wk after surgery. However, the morphologic analysis demonstrated that pulmonary vascular muscularization, as evaluated using right ventricular systolic pressure and RV/(LV + S), was not significantly increased until 4 wk postoperatively. When mice from the new model and the hypoxic model were compared, no significant differences were observed in any of the evaluated indices. High-flow PH can be induced within 4 wk after ligation of the right pulmonary artery, which is easily performed in mice. Such mice can be used as a model of high-flow PH. Copyright © 2016 Elsevier Inc. All rights reserved.

Norwood with right ventricle-to-pulmonary artery conduit is more effective than Norwood with Blalock-Taussig shunt for hypoplastic left heart syndrome: mathematic modeling of hemodynamics.

PubMed

Mroczek, Tomasz; Małota, Zbigniew; Wójcik, Elżbieta; Nawrat, Zbigniew; Skalski, Janusz

2011-12-01

The introduction of right ventricle to pulmonary artery (RV-PA) conduit in the Norwood procedure for hypoplastic left heart syndrome resulted in a higher survival rate in many centers. A higher diastolic aortic pressure and a higher mean coronary perfusion pressure were suggested as the hemodynamic advantage of this source of pulmonary blood flow. The main objective of this study was the comparison of two models of Norwood physiology with different types of pulmonary blood flow sources and their hemodynamics. Based on anatomic details obtained from echocardiographic assessment and angiographic studies, two three-dimensional computer models of post-Norwood physiology were developed. The finite-element method was applied for computational hemodynamic simulations. Norwood physiology with RV-PA 5-mm conduit and Blalock-Taussig shunt (BTS) 3.5-mm shunt were compared. Right ventricle work, wall stress, flow velocity, shear rate stress, energy loss and turbulence eddy dissipation were analyzed in both models. The total work of the right ventricle after Norwood procedure with the 5-mm RV-PA conduit was lower in comparison to the 3.5-mm BTS while establishing an identical systemic blood flow. The Qp/Qs ratio was higher in the BTS group. Hemodynamic performance after Norwood with the RV-PA conduit is more effective than after Norwood with BTS. Computer simulations of complicated hemodynamics after the Norwood procedure could be helpful in establishing optimal post-Norwood physiology. Copyright © 2011 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved.

The relationship between ischemia-induced left ventricular dysfunction, coronary flow reserve, and coronary steal on regadenoson stress-gated (82)Rb PET myocardial perfusion imaging.

PubMed

Van Tosh, Andrew; Votaw, John R; Reichek, Nathaniel; Palestro, Christopher J; Nichols, Kenneth J

2013-12-01

Gated rubidium-82 ((82)Rb) positron emission tomography (PET) imaging studies are acquired both at rest and during pharmacologic stress. Stress-induced ischemic left ventricular dysfunction (LVD) can produce a significant decrease in left ventricular ejection fraction (LVEF) from rest to stress. We determined the prevalence on PET of stress LVD with reduced ejection fraction (EF) and its association with absolute global and regional coronary flow reserve (CFR), and with relative perfusion defect summed difference score (SDS). We studied 205 patients with known or suspected coronary disease (120 M, 75 F, age 69 ± 13 years) who had clinically indicated rest/regadenoson stress (82)Rb PET/CT studies. Data were acquired in dynamic gated list mode. Global and 17-segment regional CFR values were computed from first-pass flow data using a 2-compartment model and factor analysis applied to auto-generated time-activity curves. Rest and stress LVEF and SDS were quantified from gated equilibrium myocardial perfusion tomograms using Emory Cardiac Toolbox software. LVD was defined as a change in LVEF of ≤-5% from rest to stress. A subgroup of 109 patients also had coronary angiography. Stress LVD developed in 32 patients (16%), with mean EF change of -10 ± 5%, vs +6 ± 7% for patients without LVD (P < .0001). EF was similar at rest in patients with and without stress LVD (57 ± 18% vs 56 ± 16%, P = .63), but lower during stress for patients with LVD (47 ± 20% vs 61 ± 16%, P = .0001). CFR was significantly lower in patients with LVD (1.61 ± 0.67 vs 2.21 ± 1.03, Wilcoxon P = .002), and correlated significantly with change in EF (r = 0.35, P < .0001), but not with SDS (r = -0.13, P = .07). The single variable most strongly associated with high risk of CAD (i.e., left main stenosis ≥50%, LAD % stenosis ≥70%, and/or 3-vessel disease) was stress EF (χ(2) = 17.3, P < .0001). There was a higher prevalence of patients with territorial CFR values ≤1.0, consistent with coronary steal, in the LVD group than in the non-LVD group (39% vs 12%, P = .001). LVD developed in 16% of patients undergoing (82)Rb PET myocardial perfusion imaging, and was associated with multivessel coronary artery disease. There was a significant relationship between LVD and coronary blood flow during stress, with LVD corresponding to a low CFR. Territorial CFR ≤1.0 was more common in patients with LVD than those without, suggesting that coronary steal is an important pathophysiologic mechanism contributing to pharmacologic stress-induced LVD.

Is the measurement of inferior thyroid artery blood flow velocity by color-flow Doppler ultrasonography useful for differential diagnosis between gestational transient thyrotoxicosis and Graves' disease? A prospective study.

PubMed

Zuhur, Sayid Shafi; Ozel, Alper; Velet, Selvinaz; Buğdacı, Mehmet Sait; Cil, Esra; Altuntas, Yüksel

2012-01-01

To determine the role of peak systolic velocity, end-diastolic velocity and resistance indices of both the right and left inferior thyroid arteries measured by color-flow Doppler ultrasonography for a differential diagnosis between gestational transient thyrotoxicosis and Graves' disease during pregnancy. The right and left inferior thyroid artery-peak systolic velocity, end-diastolic velocity and resistance indices of 96 patients with thyrotoxicosis (41 with gestational transient thyrotoxicosis, 31 age-matched pregnant patients with Graves' disease and 24 age- and sex-matched non-pregnant patients with Graves' disease) and 25 age and sex-matched healthy euthyroid subjects were assessed with color-flow Doppler ultrasonography. The right and left inferior thyroid artery-peak systolic and end-diastolic velocities in patients with gestational transient thyrotoxicosis were found to be significantly lower than those of pregnant patients with Graves' disease and higher than those of healthy euthyroid subjects. However, the right and left inferior thyroid artery peak systolic and end-diastolic velocities in pregnant patients with Graves' disease were significantly lower than those of non-pregnant patients with Graves' disease. The right and left inferior thyroid artery peak systolic and end-diastolic velocities were positively correlated with TSH-receptor antibody levels. We found an overlap between the inferior thyroid artery-blood flow velocities in a considerable number of patients with gestational transient thyrotoxicosis and pregnant patients with Graves' disease. This study suggests that the measurement of inferior thyroid artery-blood flow velocities with color-flow Doppler ultrasonography does not have sufficient sensitivity and specificity to be recommended as an initial diagnostic test for a differential diagnosis between gestational transient thyrotoxicosis and Graves' disease during pregnancy.

Is the measurement of inferior thyroid artery blood flow velocity by color-flow Doppler ultrasonography useful for differential diagnosis between gestational transient thyrotoxicosis and Graves' disease? A prospective study

PubMed Central

Zuhur, Sayid Shafi; Özel, Alper; Velet, Selvinaz; Buğdacı, Mehmet Sait; Çil, Esra; Altuntas, Yüksel

2012-01-01

OBJECTIVE: To determine the role of peak systolic velocity, end-diastolic velocity and resistance indices of both the right and left inferior thyroid arteries measured by color-flow Doppler ultrasonography for a differential diagnosis between gestational transient thyrotoxicosis and Graves' disease during pregnancy. METHODS: The right and left inferior thyroid artery-peak systolic velocity, end-diastolic velocity and resistance indices of 96 patients with thyrotoxicosis (41 with gestational transient thyrotoxicosis, 31 age-matched pregnant patients with Graves' disease and 24 age- and sex-matched non-pregnant patients with Graves' disease) and 25 age- and sex-matched healthy euthyroid subjects were assessed with color-flow Doppler ultrasonography. RESULTS: The right and left inferior thyroid artery-peak systolic and end-diastolic velocities in patients with gestational transient thyrotoxicosis were found to be significantly lower than those of pregnant patients with Graves' disease and higher than those of healthy euthyroid subjects. However, the right and left inferior thyroid artery peak systolic and end-diastolic velocities in pregnant patients with Graves' disease were significantly lower than those of non-pregnant patients with Graves' disease. The right and left inferior thyroid artery peak systolic and end-diastolic velocities were positively correlated with TSH-receptor antibody levels. We found an overlap between the inferior thyroid artery-blood flow velocities in a considerable number of patients with gestational transient thyrotoxicosis and pregnant patients with Graves' disease. CONCLUSIONS: This study suggests that the measurement of inferior thyroid artery-blood flow velocities with color-flow Doppler ultrasonography does not have sufficient sensitivity and specificity to be recommended as an initial diagnostic test for a differential diagnosis between gestational transient thyrotoxicosis and Graves' disease during pregnancy. PMID:22358236

Restoration of Pulsatile Flow Reduces Sympathetic Nerve Activity Among Individuals With Continuous-Flow Left Ventricular Assist Devices.

PubMed

Cornwell, William K; Tarumi, Takashi; Stickford, Abigail; Lawley, Justin; Roberts, Monique; Parker, Rosemary; Fitzsimmons, Catherine; Kibe, Julius; Ayers, Colby; Markham, David; Drazner, Mark H; Fu, Qi; Levine, Benjamin D

2015-12-15

Current-generation left ventricular assist devices provide circulatory support that is minimally or entirely nonpulsatile and are associated with marked increases in muscle sympathetic nerve activity (MSNA), likely through a baroreceptor-mediated pathway. We sought to determine whether the restoration of pulsatile flow through modulations in pump speed would reduce MSNA through the arterial baroreceptor reflex. Ten men and 3 women (54 ± 14 years) with Heartmate II continuous-flow left ventricular assist devices underwent hemodynamic and sympathetic neural assessment. Beat-to-beat blood pressure, carotid ultrasonography at the level of the arterial baroreceptors, and MSNA via microneurography were continuously recorded to determine steady-state responses to step changes (200-400 revolutions per minute) in continuous-flow left ventricular assist device pump speed from a maximum of 10,480 ± 315 revolutions per minute to a minimum of 8500 ± 380 revolutions per minute. Reductions in pump speed led to increases in pulse pressure (high versus low speed: 17 ± 7 versus 26 ± 12 mm Hg; P<0.01), distension of the carotid artery, and carotid arterial wall tension (P<0.05 for all measures). In addition, MSNA was reduced (high versus low speed: 41 ± 15 versus 33 ± 16 bursts per minute; P<0.01) despite a reduction in mean arterial pressure and was inversely related to pulse pressure (P=0.037). Among subjects with continuous-flow left ventricular assist devices, the restoration of pulsatile flow through modulations in pump speed leads to increased distortion of the arterial baroreceptors with a subsequent decline in MSNA. Additional study is needed to determine whether reduction of MSNA in this setting leads to improved outcomes. © 2015 American Heart Association, Inc.

Observation of cardiogenic flow oscillations in healthy subjects with hyperpolarized 3He MRI.

PubMed

Collier, Guilhem J; Marshall, Helen; Rao, Madhwesha; Stewart, Neil J; Capener, David; Wild, Jim M

2015-11-01

Recently, dynamic MRI of hyperpolarized (3)He during inhalation revealed an alternation of the image intensity between left and right lungs with a cardiac origin (Sun Y, Butler JP, Ferrigno M, Albert MS, Loring SH. Respir Physiol Neurobiol 185: 468-471, 2013). This effect is investigated further using dynamic and phase-contrast flow MRI with inhaled (3)He during slow inhalations (flow rate ∼100 ml/s) to elucidate airflow dynamics in the main lobes in six healthy subjects. The ventilation MR signal and gas inflow in the left lower lobe (LLL) of the lungs were found to oscillate clearly at the cardiac frequency in all subjects, whereas the MR signals in the other parts of the lungs had a similar oscillatory behavior but were smaller in magnitude and in anti-phase to the signal in the left lower lung. The airflow in the main bronchi showed periodic oscillations at the frequency of the cardiac cycle. In four of the subjects, backflows were observed for a short period of time of the cardiac cycle, demonstrating a pendelluft effect at the carina bifurcation between the left and right lungs. Additional (1)H structural MR images of the lung volume and synchronized ECG recording revealed that maximum inspiratory flow rates in the LLL of the lungs occurred during systole when the corresponding left lung volume increased, whereas the opposite effect was observed during diastole, with gas flow redirected to the other parts of the lung. In conclusion, cardiogenic flow oscillations have a significant effect on regional gas flow and distribution within the lungs. Copyright © 2015 the American Physiological Society.

Experimental Assessment of the Hydraulics of a Miniature Axial-Flow Left Ventricular Assist Device

NASA Astrophysics Data System (ADS)

Smith, P. Alex; Cohn, William; Metcalfe, Ralph

2017-11-01

A minimally invasive partial-support left ventricular assist device (LVAD) has been proposed with a flow path from the left atrium to the arterial system to reduce left ventricular stroke work. In LVAD design, peak and average efficiency must be balanced over the operating range to reduce blood trauma. Axial flow pumps have many geometric parameters. Until recently, testing all these parameters was impractical, but modern 3D printing technology enables multi-parameter studies. Following theoretical design, experimental hydraulic evaluation in steady state conditions examines pressure, flow, pressure-flow gradient, efficiency, torque, and axial force as output parameters. Preliminary results suggest that impeller blades and stator vanes with higher inlet angles than recommended by mean line theory (MLT) produce flatter gradients and broader efficiency curves, increasing compatibility with heart physiology. These blades also produce less axial force, which reduces bearing load. However, they require slightly higher torque, which is more demanding of the motor. MLT is a low order, empirical model developed on large pumps. It does not account for the significant viscous losses in small pumps like LVADs. This emphasizes the importance of experimental testing for hydraulic design. Roderick D MacDonald Research Fund.

Relationship between vertebral artery blood flow in different head positions and vertigo.

PubMed

Araz Server, Ela; Edizer, Deniz Tuna; Yiğit, Özgür; Yasak, Ahmet Görkem; Erdim, Çağrı

2018-01-01

To identify the vertebral artery blood flow in different head positions in patients with positional vertigo with no specific diagnosis. Patients with history of vestibular symptoms associated with changes in head position were enrolled into the study. Healthy volunteers were evaluated as control group. Doppler ultrasonography examination of the cervical segment of the vertebral arteries was performed under three different head positions: (i) supine position, (ii) head hyperextended and rotated to the right side and (iii) head hyperextended and rotated to the left side. In the study group, right and left vertebral artery blood flow was significantly lower in the ipsilateral hyperextended position compared to standard supine position (respectively p = .014; p = .001), but did not differ significantly when compared between the standard supine and contralateral hyperextended positions (respectively = .959; p = .669). In the control group, left and right vertebral artery blood flow did not differ significantly when the head was hyperextended to the right or left sides compared to standard supine position (p > .05). Our data demonstrated that the etiology of vestibular complaints in patients with undiagnosed positional vertigo might be related to impairment in vertebral artery blood flow according to head positions.

Echocardiographic findings in stable outpatients with properly functioning HeartMate II left ventricular assist devices.

PubMed

Topilsky, Yan; Oh, Jae K; Atchison, Fawn W; Shah, Dipesh K; Bichara, Valentina M; Schirger, John A; Kushwaha, Sudhir S; Pereira, Naveen L; Park, Soon J

2011-02-01

Continuous-flow left ventricular assist devices (LVADs) have become part of the standard of care for the treatment of advanced heart failure. However, knowledge of normal values for transthoracic echocardiographic examination and measurements in these patients are lacking. All transthoracic echocardiographic examinations in 63 consecutive patients, performed 90 and 180 days after surgery with the implantation of a HeartMate II continuous-flow LVAD between February 2007 and January 2010, were retrospectively analyzed. All patients had to be outpatients at 3 and 6 months after surgery and considered stable on LVAD therapy (New York Heart Association class I or II and no need for inotropes, intravenous furosemide, or hospitalization). End-diastolic and end-systolic diameters and left ventricular mass decreased considerably compared with baseline measurements before LVAD implantation. Mitral inflow deceleration time increased (188 ± 70 vs 132.5 ± 27 msec, P = .009) and left atrial volume (84.1 ± 33 vs 141.7 ± 62 mL, P = .003) and E/e' ratio decreased (20.3 ± 9 vs 26 ± 11, P = .01), all consistent with decreased left ventricular filling pressure. Estimated right ventricular (RV) and right atrial pressure decreased significantly (34.1 ± 10 vs 51.7 ± 14 mm Hg and 9.5 ± 5 vs 14.4 ± 5 mm Hg, respectively, P < .0001 for both). Quantitatively estimated RV function (P = .02), RV fractional area change (27.9 ± 10% vs 37.4 ± 10.9%, P < .0001), and the RV index of myocardial performance (0.32 ± 0.1 vs 0.65 ± 0.2 vs 0.32 ± .01, P < .0001) improved, suggesting improved RV efficiency. LVAD therapy resulted in significant decreases in the severity of mitral regurgitation. Tricuspid regurgitation improved in patients who had concurrent tricuspid surgical correction and was unchanged otherwise. Aortic regurgitation severity increased 3 months after LVAD implantation. There were no significant differences in any of the echocardiographic parameters in the 6-month evaluation compared with the 3-month evaluation. This is the first report of selected typical echocardiographic values in a group of stable patients with normally functioning HeartMate II continuous-flow LVADs. A stable functioning continuous LVAD is associated with evidence of efficient unloading of the left ventricle, improved RV function, significant improvement in mitral regurgitation, improvement in tricuspid regurgitation only in patients undergoing repair, and increased aortic regurgitation. These normal data provide a basis for future echocardiographic studies after LVAD implantation. Copyright © 2011 American Society of Echocardiography. Published by Mosby, Inc. All rights reserved.

Single calibration multiplane stereo-PIV: the effect of mitral valve orientation on three-dimensional flow in a left ventricle model

NASA Astrophysics Data System (ADS)

Saaid, Hicham; Segers, Patrick; Novara, Matteo; Claessens, Tom; Verdonck, Pascal

2018-03-01

The characterization of flow patterns in the left ventricle may help the development and interpretation of flow-based parameters of cardiac function and (patho-)physiology. Yet, in vivo visualization of highly dynamic three-dimensional flow patterns in an opaque and moving chamber is a challenging task. This has been shown in several recent multidisciplinary studies where in vivo imaging methods are often complemented by in silico solutions, or by in vitro methods. Because of its distinctive features, particle image velocimetry (PIV) has been extensively used to investigate flow dynamics in the cardiovascular field. However, full volumetric PIV data in a dynamically changing geometry such as the left ventricle remain extremely scarce, which justifies the present study. An investigation of the left ventricle flow making use of a customized cardiovascular simulator is presented; a multiplane scanning-stereoscopic PIV setup is used, which allows for the measurement of independent planes across the measurement volume. Due to the accuracy in traversing the illumination and imaging systems, the present setup allows to reconstruct the flow in a 3D volume performing only one single calibration. The effects of the orientation of a prosthetic mitral valve in anatomical and anti-anatomical configurations have been investigated during the diastolic filling time. The measurement is performed in a phase-locked manner; the mean velocity components are presented together with the vorticity and turbulent kinetic energy maps. The reconstructed 3D flow structures downstream the bileaflet mitral valve are shown, which provides additional insight of the highly three-dimensional flow.

Estimation of left ventricular blood flow parameters: clinical application of patient-specific CFD simulations from 4D echocardiography

NASA Astrophysics Data System (ADS)

Larsson, David; Spühler, Jeannette H.; Günyeli, Elif; Weinkauf, Tino; Hoffman, Johan; Colarieti-Tosti, Massimiliano; Winter, Reidar; Larsson, Matilda

2017-03-01

Echocardiography is the most commonly used image modality in cardiology, assessing several aspects of cardiac viability. The importance of cardiac hemodynamics and 4D blood flow motion has recently been highlighted, however such assessment is still difficult using routine echo-imaging. Instead, combining imaging with computational fluid dynamics (CFD)-simulations has proven valuable, but only a few models have been applied clinically. In the following, patient-specific CFD-simulations from transthoracic dobutamin stress echocardiography have been used to analyze the left ventricular 4D blood flow in three subjects: two with normal and one with reduced left ventricular function. At each stress level, 4D-images were acquired using a GE Vivid E9 (4VD, 1.7MHz/3.3MHz) and velocity fields simulated using a presented pathway involving endocardial segmentation, valve position identification, and solution of the incompressible Navier-Stokes equation. Flow components defined as direct flow, delayed ejection flow, retained inflow, and residual volume were calculated by particle tracing using 4th-order Runge-Kutta integration. Additionally, systolic and diastolic average velocity fields were generated. Results indicated no major changes in average velocity fields for any of the subjects. For the two subjects with normal left ventricular function, increased direct flow, decreased delayed ejection flow, constant retained inflow, and a considerable drop in residual volume was seen at increasing stress. Contrary, for the subject with reduced left ventricular function, the delayed ejection flow increased whilst the retained inflow decreased at increasing stress levels. This feasibility study represents one of the first clinical applications of an echo-based patient-specific CFD-model at elevated stress levels, and highlights the potential of using echo-based models to capture highly transient flow events, as well as the ability of using simulation tools to study clinically complex phenomena. With larger patient studies planned for the future, and with the possibility of adding more anatomical features into the model framework, the current work demonstrates the potential of patient-specific CFD-models as a tool for quantifying 4D blood flow in the heart.

[Backward flow signal in the left atrium studied by Doppler echocardiography. Differentiation from mitral regurgitation].

PubMed

Nagoshi, H; Miyairi, M; Asato, T; Naito, M; Honda, M

1983-03-01

A backward flow signal in the left atrium masquerading as mitral regurgitation was studied by a pulsed Doppler method. The subjects consisted of 20 normal volunteers, 12 cases with mitral valve prolapse syndrome, five cases with rheumatic mitral regurgitation, five cases with lone atrial fibrillation, four cases with asymmetric septal hypertrophy and three cases with the Björk-Shiley tilting disc valve in the mitral position. In two-dimensional echocardiography combined with pulsed Doppler method, a Doppler signal was recorded by locating a sample volume in the left atrium. In all of the cases with mitral valve prolapse syndrome and the cases with the prosthetic valve as well as in all of the normal subjects, the backward flow signal was observed in the left atrium. In three cases with mitral valve prolapse syndrome, it was differentiated from a transvalvular regurgitant flow signal. In all cases with rheumatic mitral regurgitation, the backward flow signal was masked by a turbulent flow signal representing regurgitation. In cases with mitral stenosis, the backward flow signal was scarcely recognized. The duration of the backward flow signal had no relationship with heart rate. The histogram of incidence on the scale of R-R interval revealed normal distribution with a mean value of 0.24 sec (+/- 0.09 sec). Therefore, in cases with tachycardia, the backward flow signal was seen throughout systole. The peak backward flow velocity of Doppler signals was correlated (r = 0.71, p less than 0.01) with the peak forward flow velocity in diastole. The faint backward flow signal seen in cases with mitral stenosis and post-extrasystolic potentiation of the backward flow signal were suggestive of the foregoing relationship. The mechanism producing the backward flow was postulated as a water hammer phenomenon caused by closure of the mitral valve.

Ventricular distension and diastolic coronary blood flow in the anaesthetized dog.

PubMed

Gattullo, D; Linden, R J; Losano, G; Pagliaro, P; Westerhof, N

1993-01-01

There appears to be no agreement as to whether or not an increase in diastolic left ventricular pressure and/or volume can cause a decrease in diastolic coronary blood flow. We investigated the problem in the anaesthetized dog using a flaccid freely distensible latex balloon inserted into the left ventricle with the animal on extracorporeal circulation and the coronary perfusion pressure constant at about 45 mm Hg. Maximal vasodilatation and suppression of autoregulation in coronary vasculature was obtained by the intracoronary infusion of dipyridamole (10-40 mg/h). Ventricular volume was changed in steps of 10 ml from 10 to 70 ml and back to 10 ml, whilst recording coronary blood flow and left ventricular pressure in the left circumflex coronary artery. Over a range of ventricular volumes from 20 to 50 ml and a concomitant rise in diastolic ventricular pressure to about 20 mm Hg there was no change in the diastolic coronary flow. Only when the ventricular volume was more than two times the control value (i.e. exceeded 50 ml) and left ventricular pressure was more than 20 mm Hg, was there a decrease in coronary flow. During the return of the volume to the control level there was a fall in diastolic flow and ventricular contractility with respect to the values obtained when the volume was increased; these two effects were transient lasting less than 10 min. It was not considered that any of the three models of the coronary circulation, waterfall, intramyocardial pump or varying elastance model could explain our results.(ABSTRACT TRUNCATED AT 250 WORDS)

Left Ventricular Assist Devices: The Adolescence of a Disruptive Technology.

PubMed

Pinney, Sean P

2015-10-01

Clinical outcomes for patients with advanced heart failure receiving left ventricular assist devices are driven by appropriate patient selection, refined surgical technique, and coordinated medical care. Perhaps even more important is innovative pump design. The introduction and widespread adoption of continuous-flow ventricular assist devices has led to a paradigm shift within the field of mechanical circulatory support, making the promise of lifetime device therapy closer to reality. The disruption caused by this new technology, on the one hand, produced meaningful improvements in patient survival and quality of life, but also introduced new clinical challenges, such as bleeding, pump thrombosis, and acquired valvular heart disease. Further evolution within this field will require financial investment to sustain innovation leading to a fully implantable, durable, and cost-effective pump for a larger segment of patients with advanced heart failure. Copyright © 2015 Elsevier Inc. All rights reserved.

Aneurysmectomy and revascularization of a large hepatic artery aneurysm.

PubMed

Adkisson, Cameron D; Sibulesky, Lens; Collis, George N; McLaughlin, Daniel W; Oldenburg, W A; Nguyen, Justin H

2011-05-01

Aneurysms of the hepatic artery are rare, but are associated with significant mortality because of their lack of symptoms at presentation and risk of rupture. We report a case of an enlarging 4-cm hepatic artery aneurysm involving the proximal common hepatic artery to the bifurcation of the right and left hepatic arteries which was found incidentally on ultrasound examination. Endovascular treatment with a stent was considered, but because of the location of the aneurysm as well as the presence of significant thrombosis involving the right and left hepatic arteries, aneurysmectomy and revascularization using saphenous vein was performed. Doppler ultrasound measurements demonstrated good flow through the graft postoperatively and at 1-month follow-up. Although a variety of endovascular techniques exist to treat hepatic artery aneurysms, our results indicate that open excision and revascularization may be required and can have a good outcome. Copyright © 2011 Annals of Vascular Surgery Inc. Published by Elsevier Inc. All rights reserved.

Time course of pressure and flow in ascending aorta during ejection.

PubMed

Perlini, S; Soldà, P L; Piepoli, M; Calciati, A; Paro, M; Marchetti, G; Meno, F; Finardi, G; Bernardi, L

1991-02-01

To analyze aortic flow and pressure relationships, 10 closed-chest anaesthetised dogs were instrumented with electromagnetic aortic flow probes and micromanometers in the left ventricle and ascending aorta. Left ventricular ejection time was divided into: time to peak flow (T1) (both pressure and flow rising), peak flow to peak pressure time (T2) (pressure rising, flow decreasing), and peak pressure to dicrotic notch time (T3) (pressure and flow both decreasing). These time intervals were expressed as percent of total ejection time. Load-active interventions rose markedly T2 (from 4.2 +/- 5.5 to 19.4 +/- 3.5 after phenylephrine (p less than 0.02); from 4.2 +/- 6.5 to 21.2 +/- 5.3 after dextran (p less than 0.02)). Conversely, dobutamine reduced T2 from 4.4 +/- 5.9 to -2.5 +/- 6.5 (p less than 0.05). Thus, during load-active interventions aortic pressure increases for a longer T2 time although forward flow is decreasing, as a result of higher aortic elastic recoil during ejection. Conversely, beta 1-adrenergic stimulation significantly shortens T2. Dynamic pressure-flow relationship is thus continuously changing during ejection. T2 seems to be inversely related to the efficiency of left ventricular ejection dynamics.

[Establishment of visceral left-right asymmetry in mammals: the role of ciliary action and leftward fluid flow in the region of Hensen's node].

PubMed

Ermakov, A S

2013-01-01

During individual development of vertebrates, the anteroposterior, dorsoventral, and left-right axes of the body are established. Although the vertebrates are bilaterally symmetric outside, their internal structure is asymmetric. Of special interest is the insight into establishment of visceral left-right asymmetry in mammals, since it has not only basic but also an applied medical significance. As early as 1976, it was hypothesized that the ciliary action could be associated with the establishment of left-right asymmetry in mammals. Currently, the majority of researchers agree that the ciliary action in the region of Hensen's node and the resulting leftward laminar fluid flow play a key role in the loss of bilateral symmetry and triggering of expression of the genes constituting the Nodal-Ptx2 signaling cascade, specific of the left side of the embryo. The particular mechanism underlying this phenomenon is still insufficiently clear. There are three competing standpoints on how leftward fluid flow induces expression of several genes in the left side of the embryo. The morphogen gradient hypothesis postulates that the leftward flow creates a high concentration of a signaling biomolecule in the left side of Hensen's node, which, in turn, stimulates triggering of.gene expression of the Nodal-Ptx2 cascade. The biomechanical hypothesis (or two-cilia model) states that the immotile cilia located in the periphery of Hensen's node act as mechanosensors, activate mechanosensory ion channels, and trigger calcium signaling in the left side of the embryo. Finally, the "shuttle-bus model" holds that leftward fluid flow carries the lipid vesicles, which are crashed when colliding immotile cilia in the periphery of Hensen's node to release the contained signaling biomolecules. It is also noteworthy that the association between the ciliary action and establishment of asymmetry has been recently discovered in representatives of the lower invertebrates. In this paper, the author considers evolution of concepts on the mechanisms underlying establishment of visceral left-right asymmetry since 1976 until the present and critically reexamines the current concepts in this field of science. According to the author, serious arguments favoring the biomechanical hypothesis for determination of left-right asymmetry in mammals have been obtained.

Effects of chewing rate and reactive hyperemia on blood flow in denture-supporting mucosa during simulated chewing.

PubMed

Ogino, Takamichi; Ueda, Takayuki; Ogami, Koichiro; Koike, Takashi; Sakurai, Kaoru

2017-01-01

We examined how chewing rate and the extent of reactive hyperemia affect the blood flow in denture-supporting mucosa during chewing. The left palatal mucosa was loaded under conditions of simulated chewing or simulated clenching for 30s, and the blood flow during loading was recorded. We compared the relative blood flow during loading under conditions that recreated different chewing rates by combining duration of chewing cycle (DCC) and occlusal time (OT): fast chewing group, typical chewing group, slow chewing group and clenching group. The relationship between relative blood flow during simulated chewing and the extent of reactive hyperemia was also analyzed. When comparing the different chewing rate, the relative blood flow was highest in fast chewing rate, followed by typical chewing rate and slow chewing rate. Accordingly, we suggest that fast chewing increases the blood flow more than typical chewing or slow chewing. There was a significant correlation between the amount of blood flow during simulated chewing and the extent of reactive hyperemia. Within the limitations of this study, we concluded that slow chewing induced less blood flow than typical or fast chewing in denture-supporting mucosa and that people with less reactive hyperemia had less blood flow in denture-supporting mucosa during chewing. Copyright © 2016 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

Relationship between regional myocardial blood flow and thallium-201 distribution in the presence of coronary artery stenosis and dipyridamole-induced vasodilation.

PubMed Central

Mays, A E; Cobb, F R

1984-01-01

This study assesses the relationship between the distribution of thallium-201 and myocardial blood flow during coronary vasodilation induced by intravenous dipyridamole in canine models of partial and complete coronary artery stenosis. 10 dogs were chronically instrumented with catheters in the left atrium and aorta and with a balloon occluder and electromagnetic flow probe on the proximal left circumflex coronary artery. Regional myocardial blood flow was measured during control conditions with radioisotope-labeled microspheres, and the phasic reactive hyperemic response to a 20-s transient occlusion was then recorded. Dipyridamole was then infused intravenously until phasic coronary blood flow increased to match peak hyperemic values. The left circumflex coronary artery was either partially occluded to reduce phasic blood flow to control values (group 1) or it was completely occluded (group 2), and thallium-201 and a second microsphere label were injected. 5 min later, the animals were sacrificed, the left ventricle was sectioned into 1-2-g samples, and thallium-201 activity and regional myocardial blood flow were measured. Curvilinear regression analyses between thallium-201 localization and myocardial blood flow during dipyridamole infusion demonstrated a slightly better fit to a second- as compared with a first-order model, indicating a slight roll-off of thallium activity as myocardial blood flow increases. During the dipyridamole infusion, the increases in phasic blood flow, the distributions of regional myocardial blood flow, and the relationships between thallium-201 localization and regional blood flow were comparable to values previously observed in exercising dogs with similar occlusions. These data provide basic validation that supports the use of intravenous dipyridamole and thallium-201 as an alternative to exercise stress and thallium-201 for evaluating the effects of coronary occlusive lesions on the distribution of regional myocardial blood flow. PMID:6715540

Noninvasive Imaging of the Coronary Vasculature Using Ultrafast Ultrasound.

PubMed

Maresca, David; Correia, Mafalda; Villemain, Olivier; Bizé, Alain; Sambin, Lucien; Tanter, Mickael; Ghaleh, Bijan; Pernot, Mathieu

2017-08-11

The aim of this study was to investigate the potential of coronary ultrafast Doppler angiography (CUDA), a novel vascular imaging technique based on ultrafast ultrasound, to image noninvasively with high sensitivity the intramyocardial coronary vasculature and quantify the coronary blood flow dynamics. Noninvasive coronary imaging techniques are currently limited to the observation of the epicardial coronary arteries. However, many studies have highlighted the importance of the coronary microcirculation and microvascular disease. CUDA was performed in vivo in open-chest procedures in 9 swine. Ultrafast plane-wave imaging at 2,000 frames/s was combined to an adaptive spatiotemporal filtering to achieve ultrahigh-sensitive imaging of the coronary blood flows. Quantification of the flow change was performed during hyperemia after a 30-s left anterior descending (LAD) artery occlusion followed by reperfusion and was compared to gold standard measurements provided by a flowmeter probe placed at a proximal location on the LAD (n = 5). Coronary flow reserve was assessed during intravenous perfusion of adenosine. Vascular damages were evaluated during a second set of experiments in which the LAD was occluded for 90 min, followed by 150 min of reperfusion to induce myocardial infarction (n = 3). Finally, the transthoracic feasibility of CUDA was assessed on 2 adult and 2 pediatric volunteers. Ultrahigh-sensitive cine loops of venous and arterial intramyocardial blood flows were obtained within 1 cardiac cycle. Quantification of the coronary flow changes during hyperemia was in good agreement with gold standard measurements (r 2  = 0.89), as well as the assessment of coronary flow reserve (2.35 ± 0.65 vs. 2.28 ± 0.84; p = NS). On the infarcted animals, CUDA images revealed the presence of strong hyperemia and the appearance of abnormal coronary vessel structures in the reperfused LAD territory. Finally, the feasibility of transthoracic coronary vasculature imaging was shown on 4 human volunteers. Ultrafast Doppler imaging can map the coronary vasculature with high sensitivity and quantify intramural coronary blood flow changes. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Revised Planning Methodology For Signalized Intersections And Operational Analysis Of Exclusive Left-Turn Lanes, A Simulation-Based Method, Part - I: Literature Review (Final Report)

DOT National Transportation Integrated Search

1996-04-01

THE STUDY INVESTIGATES THE APPLICATION OF SIMULATION ALONG WITH FIELD OBSERVATIONS FOR ESTIMATION OF EXCLUSIVE LEFT-TURN SATURATION FLOW RATE AND CAPACITY. THE ENTIRE RESEARCH HAS COVERED THE FOLLOWING PRINCIPAL SUBJECTS: (1) A SATURATION FLOW MODEL ...

A biomimetic bi-leaflet mitral prosthesis with enhanced physiological left ventricular swirl restorative capability

NASA Astrophysics Data System (ADS)

Tan, Sean Guo-Dong; Kim, Sangho; Leo, Hwa Liang

2016-06-01

Mechanical heart valve prostheses are often implanted in young patients due to their durability and long-term reliability. However, existing designs are known to induce elevated levels of blood damage and blood platelet activation. As a result, there is a need for patients to undergo chronic anti-coagulation treatment to prevent thrombosis, often resulting in bleeding complications. Furthermore, recent studies have suggested that the implantation of a mechanical prosthetic valve at the mitral position results in a significant alteration of the left ventricular flow field which may contribute to flow turbulence. This study proposes a bi-leaflet mechanical heart valve design (Bio-MHV) that mimics the geometry of a human mitral valve, with the aim of reducing turbulence levels in the left ventricle by replicating physiological flow patterns. An in vitro three-dimensional particle velocimetry imaging experiment was carried out to compare the hemodynamic performance of the Bio-MHV with that of the clinically established ATS valve. The Bio-MHV was found to replicate physiological left ventricular flow patterns and produced lower turbulence levels.

The treatment of pseudoaneurysms with flow diverters after malignant otitis externa.

PubMed

Németh, Tamás; Szakács, László; Bella, Zsolt; Majoros, Valéria; Barzó, Pál; Vörös, Erika

2017-12-01

Background We report a case of bilateral malignant otitis externa complicated with bilateral petrous internal carotid artery pseudoaneurysms and their successful treatment with a flow diverter. Case report A 68-year-old woman with serious complications of type II diabetes mellitus had malignant otitis externa on the right side. She was treated with combined antibiotic therapy and underwent mastoidectomy for mastoiditis. She presented at our hospital with acute hemorrhage from the right external auditory canal. The emergency computed tomography (CT) angiography revealed a multiobulated pseudoaneurysm at the petrous segment of the right internal carotid artery. The pseudoaneurysm was treated with a 5 × 40-mm Surpass flow diverter. Three months later, she developed a malignant external otitis on the left side. As the infection progressed, a left-sided mastoiditis, a brain abscess, and a pseudoaneurysm at the petrous segment of the left internal carotid artery developed. The pseudoaneurysm caused bleeding from the left ear, and was treated with a 5 × 50-mm Surpass flow diverter. No recurrent bleeding was observed. Four months later, a follow-up angiography showed complete occlusion of the pseudoaneurysm on the left side, but a residual aneurysm could be detected on the right side. One year after the first intervention, the follow-up CT and magnetic resonance angiography revealed the complete occlusion of the aneurysms bilaterally. Conclusion The use of a flow diverter appears to be an efficient and safe method to occlude carotid pseudoaneurysms even in an inflammatory milieu.

Is the Lecompte technique the last word on transposition of the great arteries repair for all patients? A magnetic resonance imaging study including a spiral technique two decades postoperatively.

PubMed

Rickers, Carsten; Kheradvar, Arash; Sievers, Hans-Hinrich; Falahatpisheh, Ahmad; Wegner, Philip; Gabbert, Dominik; Jerosch-Herold, Michael; Hart, Chris; Voges, Inga; Putman, Léon M; Kristo, Ines; Fischer, Gunther; Scheewe, Jens; Kramer, Hans-Heiner

2016-06-01

To compare the Lecompte technique and the spiral anastomosis (complete anatomic correction) two decades after arterial switch operation (ASO). Nine patients after primary ASO with Lecompte and 6 selected patients after spiral anastomosis were evaluated 20.8 ± 2.1 years after ASO versus matched controls. Blood flow dynamics and flow profiles (e.g. vorticity, helicity) in the great arteries were quantified from time-resolved 3D magnetic resonance imaging (MRI) phase contrast flow measurements (4D flow MR) in addition to a comprehensive anatomical and functional cardiovascular MRI analysis. Compared with spiral reconstruction, patients with Lecompte showed more vortex formation, supranatural helical blood flow (relative helicity in aorta: 0.036 vs 0.089; P < 0.01), a reduced indexed cross-sectional area of the left pulmonary artery (155 vs 85 mm²/m²; P < 0.001) and more semilunar valve dysfunctions (n = 5 vs 1). There was no difference in elastic aortic wall properties, ventricular function, myocardial perfusion and myocardial fibrosis between the two groups. Cross-sectional area of the aortic sinus was larger in patients than in controls (669 vs 411 mm²/m²; P < 0.01). In the spiral group, the pulmonary root was rotated after ASO more towards the normal left position (P < 0.01). In this study, selected patients with spiral anastomoses showed, two decades after ASO, better physiologically adapted blood flow dynamics, and attained a closer to normal anatomical position of their great arteries, as well as less valve dysfunction. Considering the limitations related to the small number of patients and the novel MRI imaging techniques, these data may provoke reconsidering the optimal surgical approaches to transposition of the great arteries repair. © The Author 2016. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

Electrochemical biotin detection based on magnetic beads and a new magnetic flow cell for screen printed electrode.

PubMed

Biscay, Julien; González García, María Begoña; Costa García, Agustín

2015-01-01

The use of the first flow-cell for magnetic assays with an integrated magnet is reported here. The flow injection analysis system (FIA) is used for biotin determination. The reaction scheme is based on a one step competitive assay between free biotin and biotin labeled with horseradish peroxidase (B-HRP). The mixture of magnetic beads modified with streptavidin (Strep-MB), biotin and B-HRP is left 15 min under stirring and then a washing step is performed. After that, 100 μL of the mixture is injected and after 30s 100 μL of 3,3',5,5'-Tetramethylbenzidine (TMB) is injected and the FIAgram is recorded applying a potential of -0.2V. The linear range obtained is from 0.01 to 1 nM of biotin and the sensitivity is 758 nA/nM. The modification and cleaning of the electrode are performed in an easy way due to the internal magnet of the flow cell. Copyright © 2014 Elsevier B.V. All rights reserved.

Flow Diversion for Treatment of Growing A2 Aneurysm in a Child: Case Report and Review of Flow Diversion for Intracranial Aneurysms in Pediatric Patients.

PubMed

Vachhani, Jay Ashok; Nickele, Christopher Michael; Elijovich, Lucas; Klimo, Paul; Arthur, Adam Stephen

2016-12-01

Intracranial flow diversion has gained increasing popularity since the approval of the Pipeline Embolization Device (PED). Although it is only approved for use in adult patients, the PED has been used to treat aneurysms in pediatric patients. We present the first reported case of the use of a PED in a pediatric patient to treat an unusual fusiform distal anterior cerebral artery aneurysm. A 12-year-old girl presented with new onset seizures and was found to have a distal left anterior cerebral artery aneurysm. Initially, this was managed conservatively, but follow-up imaging performed 4 months after presentation demonstrated enlargement of the aneurysm. The patient underwent endovascular embolization of her aneurysm with PED. This was successfully performed and the patient recovered from the procedure with no neurologic deficits. Follow-up digital subtraction angiography and magnetic resonance angiography at 6 and 12 months, respectively, showed complete occlusion of the aneurysm. We also reviewed the literature on flow diversion for treatment of pediatric intracranial aneurysms. Copyright © 2016 Elsevier Inc. All rights reserved.

Anthropogenic phosphorus flow analysis of Hefei City, China.

PubMed

Li, Sisi; Yuan, Zengwei; Bi, Jun; Wu, Huijun

2010-11-01

The substance flow analysis (SFA) method was employed to examine phosphorus flow and its connection to water pollution in the city of Hefei, China, in 2008. As human activity is the driving force of phosphorus flux from the environment to the economy, the study provides a conceptual framework for analyzing an anthropogenic phosphorus cycle that includes four stages: extraction, fabrication and manufacturing, use, and waste management. Estimates of phosphorus flow were based on existing data as well as field research, expert advice, local accounting systems, and literature. The total phosphorus input into Hefei in 2008 reached 7810 tons, mainly as phosphate ore, chemical fertilizer, pesticides, crops and animal products. Approximately 33% of the total phosphorus input left the area, and nearly 20% of that amount was discharged as waste to surface water. Effluent containing excessive fertilizer from farming operations plays an important role in phosphorus overloads onto surface water; the other major emission source is sewage discharge. We also provide suggestions for reducing phosphorus emissions, for example reducing fertilizer use, recycling farming residues, and changing human consumption patterns. Crown Copyright © 2010. Published by Elsevier B.V. All rights reserved.

The left heart can only be as good as the right heart: determinants of function and dysfunction of the right ventricle.

PubMed

Magder, Sheldon

2007-12-01

Discussions of cardiac physiology and pathophysiology most often emphasise the function of the left heart. However, right heart dysfunction plays an important role in critically ill patients and is often not recognised. This is probably because the role of the right ventricle is for generating flow more than pressure, and flow is not easy to evaluate. Of importance, when right ventricular function limits cardiac output, assessing left ventricular function gives little indication of overall cardiac performance. It has recently become evident that the right ventricle also has different genetic origins and characteristics from the left ventricle. The right and left ventricles interact through series effects, diastolic interactions and systolic interactions. The mechanisms of these, and their physiological and pathological significance are discussed.

Probe for production and measurement of acute mitral regurgitant flow in dog.

PubMed

Kléber, A G; Simon, R; Rutishauser, W

1976-02-01

A probe for production and measurement of acute mitral regurgitation in dogs is described. It consists of a tube that is introduced into the mitral valve through the left atrial appendage. Regurgitant flow through the tube is measured by an electromagnetic device. Variation of flow and zero flow are achieved by narrowing or occluding the tube with a rubber cuff. In animals weighing 30-50 kg, the probe does not produce significant mitral stenosis and the mitral leaflets fit closely around the probe during ventricular systole. The instantaneous relationship between mitral regurgitant flow (MRF) and the gradient between left ventricular and left atrial pressure shows a marked delay of MRF at the beginning and end of regurgitation. This delay can be attributed to some extent to electrical phase lag and to the small movement of the probe relative to the mitral valve during the cardiac cycle. Measurement of regurgitant stroke volume is affected by this movement only to a small extent.

Transthoracic Ultrafast Doppler Imaging of Human Left Ventricular Hemodynamic Function

PubMed Central

Osmanski, Bruno-Félix; Maresca, David; Messas, Emmanuel; Tanter, Mickael; Pernot, Mathieu

2016-01-01

Heart diseases can affect intraventricular blood flow patterns. Real-time imaging of blood flow patterns is challenging because it requires both a high frame rate and a large field of view. To date, standard Doppler techniques can only perform blood flow estimation with high temporal resolution within small regions of interest. In this work, we used ultrafast imaging to map in 2D human left ventricular blood flow patterns during the whole cardiac cycle. Cylindrical waves were transmitted at 4800 Hz with a transthoracic phased array probe to achieve ultrafast Doppler imaging of the left ventricle. The high spatio-temporal sampling of ultrafast imaging permits to rely on a much more effective wall filtering and to increase sensitivity when mapping blood flow patterns during the pre-ejection, ejection, early diastole, diastasis and late diastole phases of the heart cycle. The superior sensitivity and temporal resolution of ultrafast Doppler imaging makes it a promising tool for the noninvasive study of intraventricular hemodynamic function. PMID:25073134

Hepatic Hemodynamics and Portal Flow Modulation: The A2ALL Experience.

PubMed

Emond, Jean C; Goodrich, Nathan P; Pomposelli, James J; Baker, Talia B; Humar, Abhinav; Grant, David R; Abt, Peter; Friese, Chris E; Fisher, Robert A; Kam, Igal; Sherker, Averell H; Gillespie, Brenda W; Merion, Robert M

2017-10-01

A principal aim of the Adult-to-Adult Living Donor Liver Transplantation Cohort Study was to study hepatic blood flow and effect of portal flow modulation on graft outcomes in the setting of increasing use of smaller and left lobe grafts. Recipients of 274 living donor liver transplant were enrolled in the Adult-to-Adult Living Donor Liver Transplantation Cohort Study, including 233 (85.0%) right lobes, 40 (14.6%) left lobes, and 1 (0.5%) left lateral section. Hepatic hemodynamics were recorded after reperfusion. A total of 57 portal flow modulations were performed on 52 subjects. Modulation lowered portal pressure in 68% of subjects with inconsistent effects on hepatic arterial and portal flow. A higher rate of graft dysfunction was observed in modulated vs. unmodulated subjects (31% vs. 18%; P = 0.03); however, graft survival in modulated subjects was not different from unmodulated subjects at 3 years. These results suggest the need for a study using a prespecified portal flow modulation protocol with defined indications to better define the effects of these interventions.

Mathematical embryology: the fluid mechanics of nodal cilia

NASA Astrophysics Data System (ADS)

Smith, D. J.; Smith, A. A.; Blake, J. R.

2011-07-01

Left-right symmetry breaking is critical to vertebrate embryonic development; in many species this process begins with cilia-driven flow in a structure termed the `node'. Primary `whirling' cilia, tilted towards the posterior, transport morphogen-containing vesicles towards the left, initiating left-right asymmetric development. We review recent theoretical models based on the point-force stokeslet and point-torque rotlet singularities, explaining how rotation and surface-tilt produce directional flow. Analysis of image singularity systems enforcing the no-slip condition shows how tilted rotation produces a far-field `stresslet' directional flow, and how time-dependent point-force and time-independent point-torque models are in this respect equivalent. Associated slender body theory analysis is reviewed; this approach enables efficient and accurate simulation of three-dimensional time-dependent flow, time-dependence being essential in predicting features of the flow such as chaotic advection, which have subsequently been determined experimentally. A new model for the nodal flow utilising the regularized stokeslet method is developed, to model the effect of the overlying Reichert's membrane. Velocity fields and particle paths within the enclosed domain are computed and compared with the flow profiles predicted by previous `membrane-less' models. Computations confirm that the presence of the membrane produces flow-reversal in the upper region, but no continuous region of reverse flow close to the epithelium. The stresslet far-field is no longer evident in the membrane model, due to the depth of the cavity being of similar magnitude to the cilium length. Simulations predict that vesicles released within one cilium length of the epithelium are generally transported to the left via a `loopy drift' motion, sometimes involving highly unpredictable detours around leftward cilia [truncated

Genetic Analysis Reveals a Hierarchy of Interactions between Polycystin-Encoding Genes and Genes Controlling Cilia Function during Left-Right Determination

PubMed Central

Grimes, Daniel T.; Keynton, Jennifer L.; Buenavista, Maria T.; Jin, Xingjian; Patel, Saloni H.; Kyosuke, Shinohara; Williams, Debbie J.; Hamada, Hiroshi; Hussain, Rohanah; Nauli, Surya M.; Norris, Dominic P.

2016-01-01

During mammalian development, left-right (L-R) asymmetry is established by a cilia-driven leftward fluid flow within a midline embryonic cavity called the node. This ‘nodal flow’ is detected by peripherally-located crown cells that each assemble a primary cilium which contain the putative Ca2+ channel PKD2. The interaction of flow and crown cell cilia promotes left side-specific expression of Nodal in the lateral plate mesoderm (LPM). Whilst the PKD2-interacting protein PKD1L1 has also been implicated in L-R patterning, the underlying mechanism by which flow is detected and the genetic relationship between Polycystin function and asymmetric gene expression remains unknown. Here, we characterize a Pkd1l1 mutant line in which Nodal is activated bilaterally, suggesting that PKD1L1 is not required for LPM Nodal pathway activation per se, but rather to restrict Nodal to the left side downstream of nodal flow. Epistasis analysis shows that Pkd1l1 acts as an upstream genetic repressor of Pkd2. This study therefore provides a genetic pathway for the early stages of L-R determination. Moreover, using a system in which cultured cells are supplied artificial flow, we demonstrate that PKD1L1 is sufficient to mediate a Ca2+ signaling response after flow stimulation. Finally, we show that an extracellular PKD domain within PKD1L1 is crucial for PKD1L1 function; as such, destabilizing the domain causes L-R defects in the mouse. Our demonstration that PKD1L1 protein can mediate a response to flow coheres with a mechanosensation model of flow sensation in which the force of fluid flow drives asymmetric gene expression in the embryo. PMID:27272319

Platelet counts on admission affect coronary flow, myocardial perfusion and left ventricular systolic function after primary percutaneous coronary intervention.

PubMed

Sharif, Dawod; Abu-Salem, Mira; Sharif-Rasslan, Amal; Rosenschein, Uri

2017-10-01

Patients with acute ST-elevation myocardial infarction (STEMI) and increased platelet count treated by fibrinolysis have worse outcomes. The aim of this study was to test the hypothesis that platelet blood count at admission in patients with acute STEMI treated by primary percutaneous coronary intervention affects coronary flow, myocardial perfusion and recovery of left ventricular systolic function. A total of 174 patients presenting with acute anterior STEMI and treated with primary percutaneous coronary intervention were included and divided into subgroups of admission platelet blood count of <200 K, 200-300 K, 300-400 K and >400 K. Evaluation of coronary artery flow and myocardial blush grade was performed according to the TIMI criteria. Electrocardiographic ST elevation resolution post-primary percutaneous coronary intervention was evaluated. Doppler echocardiographic evaluation of left anterior descending coronary artery velocities early and late after primary percutaneous coronary intervention and assessment of left ventricular ejection fraction and wall motion score index (WMSI) of left ventricular and left anterior descending coronary artery territory were performed. Post-primary percutaneous coronary intervention TIMI, myocardial blush grade and ST elevation resolution were similar in all groups. Patients with platelet counts <200 K had higher peak diastolic left anterior descending coronary artery velocity both early and late after primary percutaneous coronary intervention, and higher prevalence of left anterior descending coronary artery velocity deceleration time exceeding 600 ms, (45.5% vs. 40%, P<0.05). Patients with platelet counts >400 K presented with worse left ventricular ejection fraction, left ventricular WMSI and left anterior descending coronary artery WMSI, and before discharge this subgroup had worse left ventricular WMSI and left anterior descending coronary artery WMSI, P<0.01. Patients with anterior STEMI treated by primary percutaneous coronary intervention with lower admission platelet count had higher left anterior descending coronary artery diastolic velocities, better myocardial perfusion with more patients having left anterior descending coronary artery-descending coronary artery velocity deceleration time >600 ms. Patients with higher platelet counts had lower left ventricular systolic function both at admission and before discharge.

Regional cerebral blood flow changes associated with focal electrically administered seizure therapy (FEAST).

PubMed

Chahine, George; Short, Baron; Spicer, Ken; Schmidt, Matthew; Burns, Carol; Atoui, Mia; George, Mark S; Sackeim, Harold A; Nahas, Ziad

2014-01-01

Use of electroconvulsive therapy (ECT) is limited by cognitive disturbance. Focal electrically-administered seizure therapy (FEAST) is designed to initiate focal seizures in the prefrontal cortex. To date, no studies have documented the effects of FEAST on regional cerebral blood flow (rCBF). A 72 year old depressed man underwent three single photon emission computed tomography (SPECT) scans to capture the onset and resolution of seizures triggered with right unilateral FEAST. We used Bioimage Suite for within-subject statistical analyses of perfusion differences ictally and post-ictally compared with the baseline scan. Early ictal increases in regional cerebral blood flow (rCBF) were limited to the right prefrontal cortex. Post-ictally, perfusion was reduced in bilateral frontal and occipital cortices and increased in left motor and precuneus cortex. FEAST appears to triggers focal onsets of seizure activity in the right prefrontal cortex with subsequent generalization. Future studies are needed on a larger sample. Copyright © 2014 Elsevier Inc. All rights reserved.

Analysis of the dynamics of venous blood flow in the context of lower limb temperature distribution and tissue composition in the elderly.

PubMed

Skomudek, Aleksandra; Gilowska, Iwona; Jasiński, Ryszard; Rożek-Piechura, Krystyna

2017-01-01

The elderly are particularly vulnerable to degenerative diseases, such as circulatory and respiratory system and vascular system diseases. The objective of this study was therefore to evaluate the distribution of temperature and the dynamics of venous blood flow in the lower limbs (LLs) and to assess the interdependence of these parameters in terms of the somatic components in males and females participating in activities at the University of the Third Age. The study included 60 females (mean age 67.4 years) and 40 males (mean age 67.5 years). A body composition assessment was performed using the bioimpedance technique - Tanita BC-418MA. The following parameters were examined: fat%, fat mass, fat-free mass, and total body water. The minimal, maximal, and mean temperature values and their distributions were examined using infrared thermographic camera VarioCAM Head. Measurements of the venous refilling time and the work of the LL venous pump were examined using a Rheo Dopplex II PPG. In males, the mean value of the right LL temperature was 30.58 and the mean value of the left LL was 30.28; the P -value was 0.805769. In females, the mean value of the right LL temperature was 29.58 and the mean value of the left limb was 29.52; the P -value was 0.864773. In males, the right limb blood flow was 34.17 and the left limb blood flow was 34.67; the P -value was 0.359137. In females, the right limb blood flow was 26.89 and the left limb blood flow was 26.09; the P -value was 0.796348. Research results showed that the temperature distribution and the dynamics of blood flow are not significantly different between the right and left extremities in both males and females. However, significant temperature differences were found between the gender groups. Significantly higher temperature values in both the right and left extremities were recorded in males than in females.

Neonatal piglet model of intraaortic balloon pumping: improved efficacy using echocardiographic timing.

PubMed

Minich, L L; Tani, L Y; Pantalos, G M; Bolland, B L; Knorr, B K; Hawkins, J A

1998-11-01

Pediatric intraaortic balloon pumping (IABP) has met with little success because of technical difficulty in tracking rapid heart rates. This study was designed to evaluate the efficacy of M-mode echocardiography for IABP timing in a neonatal piglet model. Two groups of piglets underwent mitral valve avulsion to create a model of shock. Group 1 (n = 8; mean weight, 7.7+/-1.8 kg) underwent IABP timed with both the ascending aortic pressure and M-mode echocardiogram. Group 2 (n = 6; mean weight, 7.5+/-1.4 kg) underwent two separate periods of IABP: one with echocardiographic timing and the second using standard timing points from the femoral arterial pressure tracing and electrocardiogram. Measurements included ascending aortic flow, left anterior descending arterial flow, ascending aortic pressure, left atrial pressure, and heart rate. Mitral valve avulsion produced a shock model with a significant decrease in mean aortic pressure and aortic flow and a significant increase in left atrial pressure and heart rate. Compared with the shock state, IABP in group 1 animals resulted in a significant increase in aortic flow (353+/-152 versus 454+/-109 mL/min; p < 0.05) and a significant decrease in left atrial pressure (23+/-6 versus 17+/-7 mm Hg; p < 0.05). Group 2 animals with echocardiogram-timed IABP had significantly increased aortic flow (365+/-106 versus 458+/-107 mL/min; p < 0.05) and mean aortic pressure (43+/-11 versus 52+/-8 mm Hg; p < 0.05). However, standard-timed IABP failed to show any improvement. In piglets with rapid heart rates, echocardiogram-timed IABP results in increased aortic flow and pressure and decreased left atrial pressure compared with standard-timed IABP.

Total vascular resistance and blood flow frequency during left ventricular assistance using a vibrating flow pump.

PubMed

Kobayashi, S; Owada, N; Yambe, T; Nitta, S; Fukuju, T; Hongoh, T; Hashimoto, H

1999-08-01

A vibrating flow pump (VFP) can generate high frequency oscillated blood flow within 10-30 Hz by the oscillation of its central tube. A totally implantable artificial heart using a VFP is being developed as a unique type of blood pump. In this study, left ventricular (LV) assist circulation was performed using a VFP. The total vascular resistance and driving frequency of the VFP were estimated from their relationship. The effect of oscillation on the vascular system was studied by the frequency analysis method and vascular impedance. Adult goats were anesthetized by halothane using an inhaler and a left fourth thoracotomy was performed. The inflow cannula was inserted into the left ventricle, and the outflow cannula was sutured to the descending aorta. The VFP and a centrifugal pump were set in parallel for alternation and comparison. The driving frequency of the VFP was changed and included 15, 20, 25, and 30 Hz. The hemodynamic parameters were continuously recorded during experiments by a digital audio tape (DAT) data recorder. The internal pressure of the left ventricular cavity and aortic pressure were monitored by the pressure manometers continuously. One hundred percent LV assistance was judged by the separation of LV and aortic pressure. The total vascular resistance was decreased by the start of operation of each pump. The decrease during flow using the VFP was not as large as that using a centrifugal pump (CP). The arterial input impedance during oscillated blood flow by the VFP showed a slow curve appearance. It was similar to the frequency characteristics curve of natural heart beats within the lower frequencies. The study of arterial impedance may be important for the estimation of the reflection of the pulsatile wave from the arterial branch, among other things.

Increase in left liver lobe function after preoperative right portal vein embolisation assessed with gadolinium-EOB-DTPA MRI.

PubMed

Geisel, Dominik; Lüdemann, Lutz; Keuchel, Thomas; Malinowski, Maciej; Seehofer, Daniel; Stockmann, Martin; Hamm, Bernd; Gebauer, Bernhard; Denecke, Timm

2013-09-01

To prospectively evaluate the early development of regional liver function after right portal vein embolisation (PVE) with Gd-EOB-DTPA-enhanced MRI in patients scheduled for extended right hemihepatectomy. Ten patients who received a PVE before an extended hemihepatectomy were examined before and 14 days after PVE using Gd-EOB-DTPA-enhanced MRI of the liver. In these sequences representative region of interest measurements were performed in the embolised right (RLL) and the non-embolised left liver lobe (LLL). The volume as well as hepatic uptake index (HUI) was calculated independently for each lobe. Relative enhancement 14 days after PVE decreased in the RLL and increased significantly in the LLL (P < 0.05). Average hepatic uptake index (HUI) for RLL was significantly lower 14 days after PVE than before PVE (P < 0.05) and significantly higher for LLL (P < 0.05). A significant shift of contrast uptake from the right to the left liver lobe can be depicted as early as 14 days after right PVE by using Gd-EOB-DTPA-enhanced MRI, which could reflect the redirected portal venous blood flow and the rapid utilisation of a hepatic functional reserve. • Preoperative portal vein embolisation (PVE) is widely performed before right-sided hepatic resection. • PVE increases intravenous contrast medium uptake in the left lobe of liver. • The hepatic uptake index for the left liver lobe increases rapidly after PVE. • Left liver lobe function increase may be visualised by Gd-EOB-DTPA-enhanced MRI.

Arrested blood flow during false aneurysm formation in the carotid arteries of cattle slaughtered with and without stunning.

PubMed

Gregory, N G; Schuster, P; Mirabito, L; Kolesar, R; McManus, T

2012-02-01

The time to onset of arrested blood flow and the size of false aneurysms in the severed carotid arteries were assessed in 126 cattle during halal slaughter without stunning. Thirty six cattle (29%) showed early arrest of blood flow. In 6%, both the left and right carotid arteries in the same animal stopped bleeding before 60s had elapsed following the neck cut. The time to early arrested blood flow was on average 21s, and this was accompanied by enlargement with false aneurysms which occluded the arteries. In the arteries which were still bleeding at 60s after the neck was cut the artery size was normal. Based on comparative data from different slaughter premises it appeared that making the cut in the neck at the first cervical vertebra instead of the second to fourth cervical vertebrae reduced the frequency of false aneurysm formation and early arrested blood flow. This was confirmed in a separate controlled trial where 100 cattle were stunned with a captive bolt and the arteries were examined following neck cutting at either the C1 or C3 positions. Copyright © 2011 Elsevier Ltd. All rights reserved.

Pulmonary venous flow determinants of left atrial pressure under different loading conditions in a chronic animal model with mitral regurgitation

NASA Technical Reports Server (NTRS)

Yang, Hua; Jones, Michael; Shiota, Takahiro; Qin, Jian Xin; Kim, Yong Jin; Popovic, Zoran B.; Pu, Min; Greenberg, Neil L.; Cardon, Lisa A.; Eto, Yoko;

Various clinical scenarios leading to development of the string sign of the internal thoracic artery after coronary bypass surgery: the role of competitive flow, a case series.

PubMed

Kolozsvari, Rudolf; Galajda, Zoltan; Ungvari, Tamas; Szabo, Gabor; Racz, Ildikó; Szerafin, Tamás; Herzfeld, István; Edes, István; Peterffy, Arpad; Koszegi, Zsolt

2012-01-30

The left internal mammary artery (LIMA) is the choice for grafting of the left anterior descending coronary artery (LAD). One possible mechanism of the rare graft failure involve the presence of competitive flow. 105 patients who had undergone coronary bypass grafting between 1998 and 2000 were included in this observational study. The recatheterizations were performed 28 months after the operations. The rate of patency the LIMA grafts was determined, and the cases with graft failure were analyzed. The LIMA graft was patent in 99 patients (94%). Six patients (6%) exhibited diffuse involution of the graft (string sign). The string sign was always associated with competitive flow as the basis of the LIMA graft involution. In one case quantitative re-evaluation of the preoperative coronary angiography revealed merely less than 50% diameter stenosis on the LAD with a nonligated side-branch of the LIMA. At recatheterization in two patients the pressure wire measurements demonstrated only a non-significant decrease of the fractional flow reserve (0.83 and 0.89), despite the 53% and 57% diameter stenosis in the angiogram. Another patient displayeda significant regression of the LAD lesion between the pre- and postoperative coronary angiography (from 76% to 44%) as the cause of the development of the competitive flow. In one instance, a radial artery graft on the LAD during a redo bypass operation resulted in competitive flow in the radial graft due to the greater diameter than that of the LIMA. In a further patient, competitive flow developed from a short sequential part of the LIMA graft between the nonsignificantly stenosed diagonal branch and the LAD, with involution of the main part of the graft to the diagonal branch. The most common cause of the development of the string sign of a LIMA graft due to competitive flow is overassessment of the lesion of the LAD. Regression of a previous lesion or some other neighboring graft can also cause the phenomenon.

Water Reserves Program. An adaptation strategy to balance water in nature

NASA Astrophysics Data System (ADS)

Lopez Perez, M.; Barrios, E.; Salinas-Rodriguez, S.; Wickel, B.; Villon, R. A.

2013-05-01

Freshwater ecosystems occupy approximately 1% of the earth's surface yet possess about 12% of all known animal species. By virtue of their position in the landscape they connect terrestrial and coastal marine biomes and provide and sustain ecosystem services vital to the health and persistence of human communities. These services include the supply of water for food production, urban and ind ustrial consumption, among others. Over the past century many freshwater ecosystems around the world have been heavily modified or lost due to the alteration of flow regimes (e.g. due to damming, canalization, diversion, over-abstraction). The synergistic impacts of land use change, changes in flows, chemical deterioration, and climate change have left many systems and their species very little room to adjust to change, while future projections indicate a steady increase in water demand for food and energy production and water supply to suit the needs of a growing world population. In Mexico, the focus has been to secure water for human development and maximize economic growth, which has resulted in allocation of water beyond available amounts. As a consequence episodic water scarcity severely constrains freshwater ecosystems and the services they provide. Climatic change and variability are presenting serious challenges to a country that already is experiencing serious strain on its water resources. However, freshwater ecosystems are recognized by law as legitimate user of water, and mandate a flow allocation for the environment ("water reserve" or "environmental flows"). Based on this legal provision the Mexican government through the National Water Commission (Conagua), with support of the Alliance WWF - Fundación Gonzalo Río Arronte, and the Interamerican Development Bank, has launched a national program to identify and implement "water reserves": basins where environmental flows will be secured and allocated and where the flow regime is then protected before over-allocation takes place. The strategy is to identify and protect basins with an availability of water that is close to their natural flow regime and that also have a high conservation value (based on prior national conservation priority definitions such as protected areas, and biodiversity conservation gap analyses) in order to implement legal restrictions on water resource development. With such protection, these systems will be best positioned to adjust and respond to water shortages, and regime shifts. To date, 189 basins around the country were identified as potential water reserves. The next step will be the nomination of these water reserves to be integrated in the National Water Reserves Program. This program forms the core of the official Mexican government adaptation strategy towards climate prepared water management, which recognizes that water reserves are the buffer society needs to face uncertainty, and reduce water scarcity risk. The development of activities that alter the natural flow regime such as dams and levees are closely examined, and would potentially be restricted.

Outcomes of percutaneous coronary intervention in intermediate coronary artery disease: fractional flow reserve-guided versus intravascular ultrasound-guided.

PubMed

Nam, Chang-Wook; Yoon, Hyuck-Jun; Cho, Yun-Kyeong; Park, Hyoung-Seob; Kim, Hyungseop; Hur, Seung-Ho; Kim, Yoon-Nyun; Chung, In-Sung; Koo, Bon-Kwon; Tahk, Seung-Jae; Fearon, William F; Kim, Kwon-Bae

2010-08-01

This study sought to evaluate the long-term clinical outcomes of a fractional flow reserve (FFR)-guided percutaneous coronary intervention (PCI) strategy compared with intravascular ultrasound (IVUS)-guided PCI for intermediate coronary lesions. Both FFR- and IVUS-guided PCI strategies have been reported to be safe and effective in intermediate coronary lesions. The study included 167 consecutive patients, with intermediate coronary lesions evaluated by FFR or IVUS (FFR-guided, 83 lesions vs. IVUS-guided, 94 lesions). Cutoff value of FFR in FFR-guided PCI was 0.80, whereas that for minimal lumen cross sectional area in IVUS-guided PCI was 4.0 mm(2). The primary outcome was defined as a composite of major adverse cardiac events including death, myocardial infarction, and ischemia-driven target vessel revascularization at 1 year after the index procedure. Baseline percent diameter stenosis and lesion length were similar in both groups (51 +/- 8% and 24 +/- 12 mm in the FFR group vs. 52 +/- 8% and 24 +/- 13 mm in the IVUS group, respectively). However, the IVUS-guided group underwent revascularization therapy significantly more often (91.5% vs. 33.7%, p < 0.001). No significant difference was found in major adverse cardiac event rates between the 2 groups (3.6% in FFR-guided PCI vs. 3.2% in IVUS-guided PCI). Independent predictors for performing intervention were guiding device: FFR versus IVUS (relative risk [RR]: 0.02); left anterior descending coronary artery versus non-left anterior descending coronary artery disease (RR: 5.60); and multi- versus single-vessel disease (RR: 3.28). Both FFR- and IVUS-guided PCI strategy for intermediate coronary artery disease were associated with favorable outcomes. The FFR-guided PCI reduces the need for revascularization of many of these lesions. Copyright (c) 2010 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Cardiac transplantation after bridged therapy with continuous flow left ventricular assist devices.

PubMed

Deo, Salil V; Sung, Kiick; Daly, Richard C; Shah, Ishan K; Altarabsheh, Salah E; Stulak, John M; Joyce, Lyle D; Boilson, Barry A; Kushwaha, Sudhir S; Park, Soon J

2014-03-01

Cardiac transplantation is an effective surgical therapy for end-stage heart failure. Patients (pts) may need to be bridged with a continuous flow left ventricular assist device (CF-LVAD) while on the transplant list as logistic factors like organ availability are unknown. Cardiac transplantation post-LVAD can be a surgically challenging procedure and outcome in these pts is perceived to be poorer based on experience with earlier generation pulsatile flow pumps. Data from a single institution comparing these pts with those undergoing direct transplantation in the present era of continuous flow device therapy are limited. Evaluate results of cardiac transplantation in pts bridged with a CF-LVAD (BTx) and compare outcomes with pts undergoing direct transplantation (Tx) in a single institution. From June 2007 till January 2012, 106 pts underwent cardiac transplantation. Among these, 37 (35%) pts (51±11 years; 85% male) were bridged with a CF-LVAD (BTx), while 70 (65%) comprised the Tx group (53±12 years; 72% males). The median duration of LVAD support was 227 (153,327) days. During the period of LVAD support, 10/37 (27%) pts were upgraded to status 1A and all were successfully transplanted. Median hospital stay in the BTx (14 days) was slightly longer than the Tx group (12 days) but not statistically significant (p=0.21). In-hospital mortality in the BTx (5%) and Tx (1%) were comparable (p=0.25). Estimated late survival in the BTx cohort was 94±7, 90±10 and 83±16% at the end of one, two and three years, respectively which was comparable to 97±4%, 93±6% and 89±9% for the Tx group (p=0.50). Cardiac transplantation after LVAD implant can be performed with excellent results. Patients can be supported on the left ventricular assist device even for periods close to a year with good outcome after cardiac transplantation. Copyright © 2013 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.

[Comparative rheoencephalographic and convective radiation encephalic thermometric studies].

PubMed

Vaĭsfel'd, D N; Korobov, S A; Petrov, A P

1996-01-01

It is for the first time that thermoassimetry of heart flows of brain right and left hemispheres presenting as predominance of radiative-convective heat radiation from the left has been revealed, the thermoassimetry gradient being rostral-caudal. Disclosed in cerebral hemispheres was complimentarity of energetic processes: the right hemisphere secures the background energy state, the left one functions in ensuring the discrete adaptive thermoenergy reactions. The thermoassimetry revealed may be the basis of other functional asymmetries of the brain. There was no parallelism between the studied parameters of circulation and heat flow.

An angiographic technique for coronary fractional flow reserve measurement: in vivo validation.

PubMed

Takarada, Shigeho; Zhang, Zhang; Molloi, Sabee

2013-03-01

Fractional flow reserve (FFR) is an important prognostic determinant in a clinical setting. However, its measurement currently requires the use of invasive pressure wire, while an angiographic technique based on first-pass distribution analysis and scaling laws can be used to measure FFR using only image data. Eight anesthetized swine were instrumented with flow probe on the proximal segment of the left anterior descending (LAD) coronary arteries. Volumetric blood flow from the flow probe (Qp), coronary pressure (Pa) and right atrium pressure (Pv) were continuously recorded. Flow probe-based FFR (FFRq) was measured from the ratio of flow with and without stenosis. To determine the angiography-based FFR (FFRa), the ratio of blood flow in the presence of a stenosis (QS) to theoretically normal blood flow (QN) was calculated. A region of interest in the LAD arterial bed was drawn to generate time-density curves using angiographic images. QS was measured using a time-density curve and the assumption that blood was momentarily replaced with contrast agent during the injection. QN was estimated from the total coronary arterial volume using scaling laws. Pressure-wire measurements of FFR (FFRp), which was calculated from the ratio of distal coronary pressure (Pd) divided by proximal pressure (Pa), were continuously obtained during the study. A total of 54 measurements of FFRa, FFRp, and FFRq were taken. FFRa showed a good correlation with FFRq (FFRa = 0.97 FFRq +0.06, r(2) = 0.80, p < 0.001), although FFRp overestimated the FFRq (FFRp = 0.657 FFRq + 0.313, r(2) = 0.710, p < 0.0001). Additionally, the Bland-Altman analysis showed a close agreement between FFRa and FFRq. This angiographic technique to measure FFR can potentially be used to evaluate both anatomical and physiological assessments of a coronary stenosis during routine diagnostic cardiac catheterization that requires no pressure wires.

Abnormal resting state corticolimbic blood flow in depressed unmedicated patients with major depression: a (15)O-H(2)O PET study.

PubMed

Monkul, E Serap; Silva, Leandro A P; Narayana, Shalini; Peluso, Marco A M; Zamarripa, Frank; Nery, Fabiano G; Najt, Pablo; Li, John; Lancaster, Jack L; Fox, Peter T; Lafer, Beny; Soares, Jair C

2012-02-01

We investigated the differences in the resting state corticolimbic blood flow between 20 unmedicated depressed patients and 21 healthy comparisons. Resting state cerebral blood flow (CBF) was measured with H(2)(15)O PET. Anatomical MRI scans were performed on an Elscint 1.9 T Prestige system for PET-MRI coregistration. Significant changes in cerebral blood flow indicating neural activity were detected using an ROI-free image subtraction strategy. In addition, the resting blood flow in patients was correlated with the severity of depression as measured by HAM-D scores. Depressed patients showed decreases in blood flow in right anterior cingulate (Brodmann areas 24 and 32) and increased blood flow in left and right posterior cingulate (Brodmann areas 23, 29, 30), left parahippocampal gyrus (Brodmann area 36), and right caudate compared with healthy volunteers. The severity of depression was inversely correlated with the left middle and inferior frontal gyri (Brodmann areas 9 and 47) and right medial frontal gyrus (Brodmann area 10) and right anterior cingulate (Brodmann areas 24, 32) blood flow, and directly correlated with the right thalamus blood flow. These findings support previous reports of abnormalities in the resting state blood flow in the limbic-frontal structures in depressed patients compared to healthy volunteers. Copyright © 2011 Wiley Periodicals, Inc.

Delayed Visual Loss and Its Surgical Rescue Following Extracranial-Intracranial Arterial Bypass and Native Internal Carotid Artery Sacrifice.

PubMed

Li, Lai-Fung; Leung, Gilberto Ka-Kit; Lui, Wai-Man

2017-02-01

High-flow extracranial-intracranial (EC-IC) bypass followed by sacrifice of the native internal carotid artery (ICA) is a recognized treatment option for giant ICA aneurysm and skull base tumor involving the ICA. Distal clipping at the supraclinoid portion of the ICA is technically straightforward, but it can potentially compromise ophthalmic artery (OA) perfusion. Because of the extensive EC-IC anastomoses with the OA, visual symptoms are fortunately uncommon. We report a patient who developed complete blindness after distal trapping of the supraclinoid ICA; it was reversed after emergency clip removal. Our patient is a 47-year-old man with recurrent nasopharyngeal carcinoma in close proximity to the left petrosal ICA. The first stage of the procedure involved an EC-IC bypass using radial artery graft, followed by a second stage with combined craniofacial excision. Trapping of the native ICA was achieved using a permanent aneurysm clip placed at the supraclinoid ICA distal to the origin of the OA. He complained of a new onset of complete left eye visual loss approximately 6 hours after the distal aneurysm clip was applied. He was immediately sent to the operating theatre for the removal of the supraclinoid aneurysm clip. On the next day, his vision improved and left pupil became reactive again. OA flow following ICA trapping is complicated and precarious. Delayed onset of visual loss is possible. Prompt action by direct exploration and clip removal is needed and can be effective in reversing blindness. Copyright © 2016 Elsevier Inc. All rights reserved.

Intraoperative left subclavian artery occlusion with left hand ischaemia and steal syndrome in the left internal thoracic artery

PubMed Central

Jelenc, Matija; Kneževič, Ivan; Stankovič, Milenko; Geršak, Borut

2012-01-01

We present a case of a 62-year old man with a left main stenosis, left coronary artery dominance, normal ejection fraction and no valvular pathology, and status post right carotid artery stenting, who was scheduled for elective coronary revascularization. We performed off-pump coronary revascularization, anastomosing the left internal thoracic artery to the left anterior descending artery, and three separate saphenous vein grafts to the intermediate artery and the first and second obtuse marginals, respectively. Proximally, the right internal thoracic artery was used as the inflow for all three venous grafts due to a heavily calcified ascending aorta. During the construction of the distal anastomoses to the obtuse marginals, the arterial pressure in the left radial artery suddenly dropped. The left hand was found to be pale and pulseless. A femoral artery catheter was placed for pressure monitoring and the anastomoses were completed as planned. Intraoperative transit-time graft flow measurement showed a reversed flow in the left internal thoracic artery. Postoperatively, angiography was performed showing a subtotal stenosis of the proximal left subclavian artery. The artery was dilated and stented. The postoperative course was uneventful and the patient was discharged on the 12th postoperative day. PMID:22767542

END-DIASTOLIC FLOW REVERSAL LIMITS THE EFFICACY OF PEDIATRIC INTRAAORTIC BALLOON PUMP COUNTERPULSATION

PubMed Central

Bartoli, Carlo R.; Rogers, Benjamin D.; Ionan, Constantine E.; Koenig, Steven C.; Pantalos, George M.

2013-01-01

OBJECTIVE Counterpulsation with an intraaortic balloon pump (IABP) has not achieved the same successes or clinical use in pediatric patients as in adults. In a pediatric animal model, IABP efficacy was investigated to determine whether IABP timing with a high-fidelity blood pressure signal may improve counterpulsation therapy versus a low-fidelity signal. METHODS In Yorkshire piglets (n=19, 13.0±0.5 kg) with coronary ligation-induced acute ischemic left ventricular failure, pediatric IABPs (5 or 7cc) were placed in the descending thoracic aorta. Inflation and deflation were timed with traditional criteria from low-fidelity (fluid-filled) and high-fidelity (micromanometer) blood pressure signals during 1:1 support. Aortic, carotid, and coronary hemodynamics were measured with pressure and flow transducers. Myocardial oxygen consumption was calculated from coronary sinus and arterial blood samples. Left ventricular myocardial blood flow and end-organ blood flow were measured with microspheres. RESULTS Despite significant suprasystolic diastolic augmentation and afterload reduction at heart rates of 105±3bmp, left ventricular myocardial blood flow, myocardial oxygen consumption, the myocardial oxygen supply/demand relationship, cardiac output, and end-organ blood flow did not change. Statistically significant end-diastolic coronary, carotid, and aortic flow reversal occurred with IABP deflation. Inflation and deflation timed with a high-fidelity versus low-fidelity signal did not attenuate systemic flow reversal or improve the myocardial oxygen supply/demand relationship. CONCLUSIONS Systemic end-diastolic flow reversal limited counterpulsation efficacy in a pediatric model of acute left ventricular failure. Adjustment of IABP inflation and deflation timing with traditional criteria and a high-fidelity blood pressure waveform did not improve IABP efficacy or attenuate flow reversal. End-diastolic flow reversal may limit the efficacy of IABP counterpulsation therapy in pediatric patients with traditional timing criteria. Investigation of alternative deflation timing strategies is warranted. PMID:24139614

The effect of topically administered latanoprost on the cochlear blood flow and hearing.

PubMed

Jang, Chul Ho; Cho, Yong Beom; Choi, Cheol Hee; Um, Jae-Young; Wang, Pa-Chun; Pak, Sok Cheon

2013-06-01

The application of intratympanic latanoprost (PGF2α analog) has been recently used to alleviate vertigo, disequilibrium and to improve hearing in Meniere's disease patients. However, there is no known report on the effect of topically applied latanoprost on hearing and cochlear hemodynamic parameters including cochlear blood flow (CBF) and vascular conductance. Our goal was to assess the influence of topically applied latanoprost on cochlear blood flow (CBF) and hearing. Twenty male Sprague-Dawley rats were randomly divided into the group A, 50 μl of latanoprost (1 ml containing 50 μg, n=10) and group B, 100 μl (1 ml containing 50 μg, n=10). Topical application of latanoprost was performed at the right side, and the left side was applied with phosphate buffered saline (PBS) as a negative control. Five rats at each group were used to measure cochlear blood flow (CBF). And the others at each group were used for hearing test by auditory brainstem response (ABR). After physiological examination, bullas were extracted. The changes of cochlear hair cells were observed by performing the field emission-scanning electron microscopy (FE-SEM). The CBF of both groups was found to be decreased compared to the PBS applied left side. Significant decrement of CBF was observed in group B compared to the group A. Significant elevation of hearing threshold at high frequencies was observed in both groups compared to the PBS applied group. However, inner and outer hair cells were intact. Topically administered latanoprost decreased the CBF and impaired hearing. Based on our findings, additional studies are required to evaluate the side effects of intratympanic latanoprost before its use in clinical practice. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Continuous Flow Left Ventricular Assist Device Implant Significantly Improves Pulmonary Hypertension, Right Ventricular Contractility, and Tricuspid Valve Competence

PubMed Central

Atluri, Pavan; Fairman, Alexander S.; MacArthur, John W.; Goldstone, Andrew B.; Cohen, Jeffrey E.; Howard, Jessica L.; Zalewski, Christyna M.; Shudo, Yasuhiro; Woo, Y. Joseph

2014-01-01

Background Continuous flow left ventricular assist devices (CF LVAD) are being implanted with increasing frequency for end-stage heart failure. At the time of LVAD implant, a large proportion of patients have pulmonary hypertension, right ventricular (RV) dysfunction, and tricuspid regurgitation (TR). RV dysfunction and TR can exacerbate renal dysfunction, hepatic dysfunction, coagulopathy, edema, and even prohibit isolated LVAD implant. Repairing TR mandates increased cardiopulmonary bypass time and bicaval cannulation, which should be reserved for the time of orthotopic heart transplantation. We hypothesized that CF LVAD implant would improve pulmonary artery pressures, enhance RV function, and minimize TR, obviating need for surgical tricuspid repair. Methods One hundred fourteen continuous flow LVADs implanted from 2005 through 2011 at a single center, with medical management of functional TR, were retrospectively analyzed. Pulmonary artery pressures were measured immediately prior to and following LVAD implant. RV function and TR were graded according to standard echocardiographic criteria, prior to, immediately following, and long-term following LVAD. Results There was a significant improvement in post-VAD mean pulmonary arterial pressures (26.6 ± 4.9 vs. 30.2 ± 7.4 mmHg, p = 0.008) with equivalent loading pressures (CVP = 12.0 ± 4.0 vs. 12.1 ± 5.1 p = NS). RV function significantly improved, as noted by right ventricular stroke work index (7.04 ± 2.60 vs. 6.05 ± 2.54, p = 0.02). There was an immediate improvement in TR grade and RV function following LVAD implant, which was sustained long term. Conclusion Continuous flow LVAD implant improves pulmonary hypertension, RV function, and tricuspid regurgitation. TR may be managed nonoperatively during CF LVAD implant. PMID:24118109

Long-Term Survival in Patients Receiving a Continuous-Flow Left Ventricular Assist Device.

PubMed

Gosev, Igor; Kiernan, Michael S; Eckman, Peter; Soleimani, Behzad; Kilic, Ahmet; Uriel, Nir; Rich, Jonathan D; Katz, Jason N; Cowger, Jennifer; Lima, Brian; McGurk, Siobhan; Brisco-Bacik, Meredith A; Lee, Sanjin; Joseph, Susan M; Patel, Chetan B

2018-03-01

Long-term survivors after implantation of left ventricular assist devices (LVADs) are increasing in prevalence. We describe the characteristics and outcomes in patients surviving longer than 4 years on LVAD support. We performed a multicenter, retrospective analysis of patients surviving at least 4 years on continuous-flow LVAD (CF-LVAD) support with a HeartMate II at centers participating in the Evolving Mechanical support Research Group. Between 2005 and 2010, 156 long-term survivors were identified with a mean survival of 7.1 years (95% confidence interval: 6.7 to 7.5 years). The mean age was 58.2 ± 15.2 years and 30.1% were women. Readmission rate was low at 1.1 events per patient per year with the most common reasons leading to readmission being infection (0.10 readmissions per patient per year) and gastrointestinal bleeding (0.07 readmissions per patient per year). Two years after implantation, 97% of patients were either New York Heart Association functional class I or II, with 92% at 4 years. Patients surviving 4 years on CF-LVAD support can anticipate ongoing long-term survival with sustained improvements in functionality and low rates of rehospitalization. Copyright © 2018 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

PIERCE1 is critical for specification of left-right asymmetry in mice.

PubMed

Sung, Young Hoon; Baek, In-Jeoung; Kim, Yong Hwan; Gho, Yong Song; Oh, S Paul; Lee, Young Jae; Lee, Han-Woong

2016-06-16

The specification of left-right asymmetry of the visceral organs is precisely regulated. The earliest breakage of left-right symmetry occurs as the result of leftward flow generated by asymmetric beating of nodal cilia, which eventually induces asymmetric Nodal/Lefty/Pitx2 expression on the left side of the lateral plate mesoderm. PIERCE1 has been identified as a p53 target gene involved in the DNA damage response. In this study, we found that Pierce1-null mice exhibit severe laterality defects, including situs inversus totalis and heterotaxy with randomized situs and left and right isomerisms. The spectrum of laterality defects was closely correlated with randomized expression of Nodal and its downstream genes, Lefty1/2 and Pitx2. The phenotype of Pierce1-null mice most closely resembled that of mutant mice with impaired ciliogenesis and/or ciliary motility of the node. We also found the loss of asymmetric expression of Cerl2, the earliest flow-responding gene in the node of Pierce1-null embryos. The results suggest that Pierce1-null embryos have defects in generating a symmetry breaking signal including leftward nodal flow. This is the first report implicating a role for PIERCE1 in the symmetry-breaking step of left-right asymmetry specification.

First report of 90-day support of 2 calves with a continuous-flow total artificial heart.

PubMed

Karimov, Jamshid H; Moazami, Nader; Kobayashi, Mariko; Sale, Shiva; Such, Kimberly; Byram, Nicole; Sunagawa, Gengo; Horvath, David; Gao, Shengqiang; Kuban, Barry; Golding, Leonard A R; Fukamachi, Kiyotaka

2015-09-01

The Cleveland Clinic continuous-flow total artificial heart (CFTAH) is a compact, single-piece, valveless, pulsatile pump providing self-regulated hemodynamic output to left/right circulation. We evaluated chronic in vivo pump performance, physiologic and hemodynamic parameters, and biocompatibility of the CFTAH in a well-established calf model. CFTAH pumps have been implanted in 17 calves total. Hemodynamic parameters, pump performance, and device-related adverse events were evaluated during studies and at necropsy. In vivo experiments demonstrated good hemodynamic performance (pump flow, 7.3 ± 0.7 L/min; left atrial pressure, 16 ± 3 mm Hg; right atrial pressure, 17 ± 3 mm Hg; right atrial pressure-left atrial pressure difference, 1 ± 2 mm Hg; mean arterial pressure, 103 ± 7 mm Hg; arterial pulse pressure, 30 ± 11 mm Hg; and pulmonary arterial pressure, 34 ± 5 mm Hg). The CFTAH has operated within design specifications and never failed. With ever-improving pump design, the implants have shown no chronic hemolysis. Three animals with recent CFTAH implantation recovered well, with no postoperative anticoagulation, during planned in vivo durations of 30, 90, and 90 days (last 2 were intended to be 90-day studies). All these longest-surviving cases showed good biocompatibility, with no thromboembolism in organs. The current CFTAH has demonstrated reliable self-regulation of hemodynamic output and acceptable biocompatibility without anticoagulation throughout 90 days of chronic implantation in calves. Meeting these milestones is in accord with our strategy to achieve transfer of this unique technology to human surgical practice, thus filling the urgent need for cardiac replacement devices as destination therapy. Copyright © 2015 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

Coronary flow characteristics after a Bentall procedure with or without sinuses of Valsalva.

PubMed

de Paulis, Ruggero; Tomai, Fabrizio; Bertoldo, Fabio; Ghini, Anna S; Scaffa, Raffaele; Nardi, Paolo; Chiariello, Luigi

2004-07-01

The sinuses of Valsalva are known to contribute to the normal function of the aortic valve. Little is known about their role in promoting coronary artery blood flow. The aim of this study was to compare coronary artery flow characteristics among patients undergoing a Bentall operation by means of a conventional cylindrical Dacron conduit or with a new conduit with pseudosinuses of Valsalva or in patients retaining their natural sinuses of Valsalva after aortic valve and supracoronary ascending aorta replacement. One year after a Bentall procedure with a standard cylindrical Dacron conduit (7 patients, group A) or with the new conduit (7 patients, group B), or after aortic valve and ascending aortic replacement (control group, 7 patients, group C) coronary flow velocity reserve and diastolic to systolic time integral ratio at baseline and after maximal hyperemia (with 40 microg of adenosine) were assessed by using a 0.014-in. Doppler guidewire positioned in the middle portion of the left anterior descending coronary artery. All patients were in NYHA class I, sinus rhythm and free of coronary disease. Arterial blood pressures and heart rate were comparable among groups. Intracoronary Doppler measurements did not show any significant difference in coronary vascular reserve between the three groups (3.6+/-0.4 vs 3.1+/-0.7 vs 3.7+/-0.5, P = 0.2). A greater diastolic component at baseline was present in group B patients (5.5+/-1.9 vs 3.5+/-0.9 in group A and 3.7+/-0.9 in group C, P = 0.024). After maximal hyperemia the diastolic component increased slightly in group A patients (8%) while both in groups B and C significantly decreased (-15 and -20%, respectively) (P = 0.017). The presence of pseudosinuses of Valsalva does not influence coronary flow reserve. After maximal coronary vasodilation the increase in the systolic component of coronary flow is more evident in the presence of sinuses or pseudosinuses of Valsalva, thus suggesting that coronary flow pattern may be affected by the presence of sinuses.

Aberrant left subclavian artery occlusion in right-sided aortic artery associated with left cerebral infarction: A case report.

PubMed

Tempaku, Akira; Kuroiwa, Terumasa; Nishio, Akimasa

2018-06-01

Purpose Right-sided aortic arch is a rare vessel anomaly with an incidence of 0.1% worldwide. Supra-aortic branches form a mirror image of the left-sided aortic arch or an aberrant left subclavian artery associated with Kommerell diverticulum. Most patients are diagnosed by a difference in blood pressure in each upper extremity or by the presence of left subclavian steal syndrome in their younger age. The diagnosis of onset of ischemic stroke in middle age is rare. Methods We present the case of a female patient who presented with an ischemic stroke in the left posterior circulation area. She had no history of congenital heart malformation. We performed head magnetic resonance imaging, cerebral angiography, and enhanced computed tomography of the aortic arch and major branches. Results The patient had a right-sided aortic arch and an aberrant left subclavian artery. The left subclavian artery was occluded at the proximal portion with a fibrous string. Collateral flow in the anterior cervical subcutaneous area supported left limb perfusion. Conclusion An atheromatous change reduced shunt flow via collateral networks at the anterior cervical region. Congenital subclavian steal supported the ischemic stroke.

Hypoxic pulmonary vasoconstriction does not affect hydrostatic pulmonary edema formation.

PubMed

Cheney, F W; Bishop, M J; Eisenstein, B L; Artman, L D

1987-02-01

We studied the effects of regional hypoxic pulmonary vasoconstriction (HPV) on lobar flow diversion in the presence of hydrostatic pulmonary edema. Ten anesthetized dogs with the left lower lobe (LLL) suspended in a net for continuous weighing were ventilated with a bronchial divider so the LLL could be ventilated with either 100% O2 or a hypoxic gas mixture (90% N2-5% CO2-5% O2). A balloon was inflated in the left atrium until hydrostatic pulmonary edema occurred, as evidenced by a continuous increase in LLL weight. Left lower lobe flow (QLLL) was measured by electromagnetic flow meter and cardiac output (QT) by thermal dilution. At a left atrial pressure of 30 +/- 5 mmHg, ventilation of the LLL with the hypoxic gas mixture caused QLLL/QT to decrease from 17 +/- 4 to 11 +/- 3% (P less than 0.05), pulmonary arterial pressure to increase from 35 +/- 5 to 37 +/- 6 mmHg (P less than 0.05), and no significant change in rate of LLL weight gain. Gravimetric confirmation of our results was provided by experiments in four animals where the LLL was ventilated with an hypoxic gas mixture for 2 h while the right lung was ventilated with 100% O2. In these animals there was no difference in bloodless lung water between the LLL and right lower lobe. We conclude that in the presence of left atrial pressures high enough to cause hydrostatic pulmonary edema, HPV causes significant flow diversion from an hypoxic lobe but the decrease in flow does not affect edema formation.

Sensitivity analysis of geometrical parameters to study haemodynamics and thrombus formation in the left atrial appendage.

PubMed

García-Isla, Guadalupe; Olivares, Andy Luis; Silva, Etelvino; Nuñez-Garcia, Marta; Butakoff, Constantine; Sanchez-Quintana, Damian; G Morales, Hernán; Freixa, Xavier; Noailly, Jérôme; De Potter, Tom; Camara, Oscar

2018-05-08

The left atrial appendage (LAA) is a complex and heterogeneous protruding structure of the left atrium (LA). In atrial fibrillation patients, it is the location where 90% of the thrombi are formed. However, the role of the LAA in thrombus formation is not fully known yet. The main goal of this work is to perform a sensitivity analysis to identify the most relevant LA and LAA morphological parameters in atrial blood flow dynamics. Simulations were run on synthetic ellipsoidal left atria models where different parameters were individually studied: pulmonary veins and mitral valve dimensions; LAA shape; and LA volume. Our computational analysis confirmed the relation between large LAA ostia, low blood flow velocities and thrombus formation. Additionally, we found that pulmonary vein configuration exerted a critical influence on LAA blood flow patterns. These findings contribute to a better understanding of the LAA and to support clinical decisions for atrial fibrillation patients. Copyright © 2018 John Wiley & Sons, Ltd.

Maternal bradycardia occurring prior to onset of HELLP syndrome in a woman with pre-eclampsia.

PubMed

Hosokawa, Ami; Umazume, Takeshi; Yamada, Takahiro; Minakami, Hisanori

2017-05-13

A 36-year-old nulliparous woman developed pre-eclampsia at gestational week (GW) 28 -6/7 Cardiac status was checked regularly. Heart rate of 93 beats per minute (bpm) with left atrial diameter (LAD) of 35 mm, left ventricular hypertrophy and inferior vena cava diameter (IVCD) of 8 mm at GW 32 -0/7 decreased to 48 bpm with an expanded IVCD to 25 mm, dilated left atrium (LAD to 39 mm), increased pulmonary arterial pressure, increased systemic vascular resistance (approximate 3000  dyn s/cm 5 ) and biphasic intrarenal venous flow pattern 3.5 hours prior to childbirth at GW 32 -3/7 Epigastralgia, tachycardia (160 bpm) and marked hypertension (201/111 mm Hg) occurring 2 hours after echocardiography necessitated caesarean section, with subsequent development of HELLP syndrome. Acute fluid shift from the splanchnic vasculature to central vasculature may have occurred causing HELLP syndrome as a result from vasospasm associated with sympathetic hyperactivity. The cause of bradycardia prior to tachycardia remains unclear. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Comparison of intracoronary versus intravenous administration of adenosine for measurement of coronary fractional flow reserve.

PubMed

Schlundt, Christian; Bietau, Christian; Klinghammer, Lutz; Wiedemann, Ricarda; Rittger, Harald; Ludwig, Josef; Achenbach, Stephan

2015-05-01

Measurement of fractional flow reserve (FFR) constitutes the current gold standard to evaluate the hemodynamic significance of coronary stenoses. Limited data validate the intracoronary application of adenosine against standard intravenous infusion. We systematically compared FFR measurements during intracoronary and intravenous application of adenosine about agreement and reproducibility. We included 114 patients with an intermediate degree of stenosis in coronary angiography. Two FFR measurements were performed during intracoronary bolus injection (40 μg for the right and 80 μg for the left coronary artery, FFRic), and 2 FFR measurements during continuous intravenous infusion of adenosine (140 μg/kg per minute, FFRiv). FFR value, the time to reach FFR and patient discomfort (on a subjective scale from 0 for no symptoms to 5 for maximal discomfort) were recorded for each measurement. Mean time to FFR was 100 ± 27 s for continuous intravenous infusion versus 23 ± 14 s for intracoronary bolus administration of adenosine (P < 0.001). Reported discomfort after intracoronary application was significantly lower compared with intravenous adenosine (subjective scale > 0 in 35.1% versus 87.7% of the patients; P < 0.001). Correlation between FFRiv and FFRic was extremely close (r = 0.99; P < 0.001) with no systematic bias in Bland-Altman analysis (bias 0.002 [confidence interval, -0.001 to 0.005]) and low intermethod variability (1.56%). Intramethod variability was not different between intravenous and intracoronary administration (1.47% versus 1.33%; P=0.5). Intracoronary bolus injection of adenosine (40 μg for the right and 80 μg for the left coronary artery) yields identical FFR results compared with intravenous infusion (140 μg/kg per minute), while requiring less time and offering superior patient comfort. © 2015 American Heart Association, Inc.

Mechanism for generation of left isomerism in Ccdc40 mutant embryos

PubMed Central

Sugrue, Kelsey F.

2017-01-01

Leftward fluid flow in the mouse node is generated by cilia and is critical for initiating asymmetry of the left-right axis. Coiled-coil domain containing-40 (Ccdc40) plays an evolutionarily conserved role in the assembly of motile cilia and establishment of the left-right axis. Approximately one-third of Ccdc40lnks mutant embryos display situs defects and here we investigate the underlying mechanism. Ccdc40lnks mutants show delayed induction of markers of the left-lateral plate mesoderm (L-LPM) including Lefty1, Lefty2 and Nodal. Consistent with defective cilia motility compromising fluid flow across the node, initiation of asymmetric perinodal Cerberus like-2 (Cerl2) expression is delayed and then randomized. This is followed by delayed and then randomized asymmetric Nodal expression around the node. We propose a model to explain how left isomerism arises in a proportion of Ccdc40lnks mutants. We postulate that with defective motile cilia, Cerl2 expression remains symmetric and Nodal is antagonized equally on both sides of the node. This effectively reduces Nodal activation bilaterally, leading to reduced and delayed activation of Nodal and its antagonists in the LPM. This model is further supported by the failure to establish Nodal expression in the left-LPM with reduced Nodal gene dosage in Ccdc40lnks/lnks;NodalLacZ/+ mutants causing a predominance of right not left isomerism. Together these results suggest a model where cilia generated fluid flow in the node functions to ensure robust Nodal activation and a timely left-sided developmental program in the LPM. PMID:28182636

Anthropomorphic cardiac ultrasound phantom.

PubMed

Smith, S W; Rinaldi, J E

1989-10-01

A new phantom is described which simulates the human cardiac anatomy for applications in ultrasound imaging, ultrasound Doppler, and color-flow Doppler imaging. The phantom consists of a polymer left ventricle which includes a prosthetic mitral and aortic valve and is connected to a mock circulatory loop. Aerated tap water serves as a blood simulating fluid and ultrasound contrast medium within the circulatory loop. The left ventricle is housed in a Lexan ultrasound visualization chamber which includes ultrasound viewing ports and acoustic absorbers. A piston pump connected to the visualization chamber by a single port pumps degassed water within the chamber which in turn pumps the left ventricle. Real-time ultrasound images and Doppler studies measure flow patterns through the valves and within the left ventricle.

Dynamical relations for left ventricular ejection - Flow rate, momentum, force and impulse

NASA Technical Reports Server (NTRS)

Back, L. H.; Selzer, R. H.; Gordon, D. G.; Ledbetter, D. C.; Crawford, D. W.

1984-01-01

An investigation was carried out to quantitatively evaluate left ventricular volume flow rate, momentum, force and impulse derived from application of conservation principles for mass and momentum of blood within the ventricle during the ejection phase. An automated digital image processing system was developed and applied to left ventricular angiograms which are computer processed and analyzed frame by frame to determine the dynamical relations by numerical methods. The initial experience with force and impulse has indicated that neither quantity seemed to be a sensitive indicator of coronary artery disease as evaluated by qualitative angiography for the particular patient group studied. Utilization of the dynamical relations in evaluating human left ventricular performance requires improved means of measurement and interpretation of clinical studies.

Echocardiographic predictors of adverse outcomes after continuous left ventricular assist device implantation.

PubMed

Topilsky, Yan; Oh, Jae K; Shah, Dipesh K; Boilson, Barry A; Schirger, John A; Kushwaha, Sudhir S; Pereira, Naveen L; Park, Soon J

2011-03-01

The purpose of the study was to identify echocardiographic predictors of adverse outcome in patients implanted with continuous-flow left ventricular assist devices (LVAD). Continuous flow LVAD have become part of the standard of care for the treatment of advanced heart failure. However, knowledge of echocardiographic predictors of outcome after LVAD are lacking. Overall, 83 patients received continuous-flow LVAD (HeartMate II, Thoratec Corporation, Pleasanton, California) from February 2007 to June 2010. The LVAD database, containing various echocardiographic parameters, was examined to analyze their influence on in-hospital mortality, a compound cardiac event (in-hospital mortality or acute right ventricular [RV] dysfunction), and long-term mortality. Eight patients died before discharge (operative mortality 9.6%), and another 15 patients were considered to have acute RV dysfunction immediately after surgery. Patients with relatively small left ventricular end-diastolic diameters (<63 mm) had significantly higher risk for in-hospital mortality (odds ratio [OR]: 0.9; 95% confidence interval [CI]: 0.83 to 0.99; p = 0.04) or occurrence of the compound cardiac event (OR: 0.89; 95% CI: 0.84 to 0.95; p < 0.001). The most significant predictor of outcome was the decreased timing interval between the onset and the cessation of tricuspid regurgitation flow corrected for heart rate (TRDc), a surrogate for early systolic equalization of RV and right atrial pressure. Short TRDc predicted in-hospital mortality (OR: 0.85; 95% CI: 0.74 to 0.97; p = 0.01) and the compound cardiac event (OR: 0.83; 95% CI: 0.74 to 0.91; p < 0.0001). Multivariate analysis based on a logistic regression model demonstrated that the accuracy of predicting the 30-day compound adverse outcome was improved with the addition of echocardiographic variables when added to the commonly used hemodynamic or clinical scores. TRDc predicted long-term survival, with adjusted risk ratios of 0.89 for death from any cause (95% CI: 0.83 to 0.96; p = 0.003) and 0.88 for cardiac-related death (95% CI: 0.77 to 0.98; p = 0.03). The presence of either a relatively small left ventricle (<63 mm) or early systolic equalization of RV and right atrial pressure (short TRDc) demonstrated by echocardiography is associated with increased 30-day morbidity and mortality. Prediction of early adverse outcomes by echocardiographic parameters is additive to laboratory or hemodynamic variables. Copyright © 2011 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

[Short and long-term changes in cortical circulation caused by autogenic training].

PubMed

Meyer, H K; Diehl, B J; Ulrich, P; Meinig, G

1987-01-01

The well-known hyperfrontal pattern of hemispheric blood flow measured with 133-Xenon is not found in 12 healthy resting men who have been practicing Autogenic Training for at least six months. This might indicate a long-term decrease in the level of activation. Successfully practiced exercises of Autogenic Training lead to an increased blood flow in the Rolandic area representing the body sceme and to a decreased blood flow in regions related to acoustical attention and to autonomic functions. Left hemispheric cerebral blood flow ist lower in rest. The relative activation of the left hemisphere during Autogenic Training is discussed.

Accuracy of right and left ventricular functional assessment by short-axis vs axial cine steady-state free-precession magnetic resonance imaging: intrapatient correlation with main pulmonary artery and ascending aorta phase-contrast flow measurements.

PubMed

James, Susan H; Wald, Rachel; Wintersperger, Bernd J; Jimenez-Juan, Laura; Deva, Djeven; Crean, Andrew M; Nguyen, Elsie; Paul, Narinder S; Ley, Sebastian

2013-08-01

The left ventricle (LV) is routinely assessed with cardiac magnetic resonance imaging (MRI) by using short-axis orientation; it remains unclear whether the right ventricle (RV) can also be adequately assessed in this orientation or whether dedicated axial orientation is required. We used phase-contrast (PC) flow measurements in the main pulmonary artery (MPA) and the ascending aorta (Aorta) as nonvolumetric standard of reference and compared RV and LV volumes in short-axis and axial orientations. A retrospective analysis identified 30 patients with cardiac MRI data sets. Patients underwent MRI (1.5 T or 3 T), with retrospectively gated cine steady-state free-precession in axial and short-axis orientations. PC flow analyses of MPA and Aorta were used as the reference measure of RV and LV output. There was a high linear correlation between MPA-PC flow and RV-stroke volume (SV) short axis (r = 0.9) and RV-SV axial (r = 0.9). Bland-Altman analysis revealed a mean offset of 1.4 mL for RV axial and -2.3 mL for RV-short-axis vs MPA-PC flow. There was a high linear correlation between Aorta-PC flow and LV-SV short-axis (r = 0.9) and LV-SV axial (r = 0.9). Bland-Altman analysis revealed a mean offset of 4.8 m for LV short axis and 7.0 mL for LV axial vs Aorta-PC flow. There was no significant difference (P = .6) between short-axis-LV SV and short-axis-RV SV. No significant impact of the slice acquisition orientation for determination of RV and LV stroke volumes was found. Therefore, cardiac magnetic resonance workflow does not need to be extended by an axial data set for patients without complex cardiac disease for assessment of biventricular function and volumes. Copyright © 2013 Canadian Association of Radiologists. Published by Elsevier Inc. All rights reserved.

Coronary flow reserve in mitral stenosis before and after percutaneous balloon mitral valvuloplasty.

PubMed

Mahfouz, Ragab A; Gouda, Mohammad; Elawdy, Waleed; Dewedar, Ashraf

2017-09-01

We aimed to evaluate the coronary flow reserve (CFR) before and after percutaneous balloon mitral valvuloplasty (PBMV) in patients with mitral stenosis (MS) and its association to clinical events. A prospective study included 45 patients with mitral stenosis candidate for PBMV (age 38 ± 19 years, 27 were females) and 20 with matched age and sex, healthy controls were included in the study. Noninvasive CFR was measured using transthoracic echocardiography and utilizing adenosine stress echocardiography (0.14 mg/kg/min) before PMBV, and one weak post PBMV using multi-tract balloon valvuloplasty technique. CFR was significantly lower in patients with MS compared to controls (P < 0.001). Moreover the CFR was significantly increased post-PBMV (P < 0.001) associated with significant increase in LVEF% (P < 0.05), decrease in systolic pulmonary artery pressure (P < 0.001), significant increase in TAPSE (P < 0.001). CFR was significantly correlated with the degree of change (Δ) in MVA, TAPSE, LVEF%, mean mitral PG and sPAP (r = 0.77, P < 0.001, r = 0.63; P < 0.001; r = 0.42; P < 0.05; r = -0.81; P < 0.001 and r = -0.65; P < 0.001). Mitral valve stenosis was associated with significantly impaired coronary flow reserve that significantly improved after PMBV. The improved CFR values were significantly correlated with the gain in the MVA and the improvement in the functions of both left and right ventricles.

Hemodynamics on abrupt stoppage of centrifugal pumps during left ventricular assist.

PubMed

Kono, S; Nishimura, K; Nishina, T; Akamatsu, T; Komeda, M

2000-01-01

A magnetically suspended centrifugal pump (MSCP), developed for long-term ventricular assist, is reliable and durable because it has no shaft or seal. However, with nonvalve pumps such as a MSCP, regurgitation occurs when they accidentally stop without cannula clamping. We investigated the hemodynamics during temporary stoppage of a MSCP being used as a left ventricular assist system (LVAS), comparing two inflow cannulation sites. In four sheep (weight, 35-45 kg), microspheres were injected into the left main coronary artery to induce heart failure. An outflow cannula was sutured onto the descending aorta, and two inflow cannulae were inserted into the left atrium and the left ventricle. The MSCP was stopped with both the left ventricular cannula and left atrial cannula clamped, and the hemodynamics and P-V loops were recorded. Each cannula was then unclamped in order, and similar parameters were recorded. LVEDP increased at unclamping of the left ventricular cannula (ULVC), and rose further at unclamping of the left atrial cannula (ULAC). Aortic pressure did not change at ULVC, but decreased at ULAC. The effective systemic flow that subtracted the regurgitant flow through the MSCP from left ventricular output was half at ULVC and almost 0 at ULAC. When stopping centrifugal pumps without circuit clamping, hemodynamic deterioration is less at ULVC than at ULAC. This finding suggests that left ventricular inflow cannulation is recommended to allow more time in emergency situations.

Transient integral boundary layer method to calculate the translesional pressure drop and the fractional flow reserve in myocardial bridges.

PubMed

Bernhard, Stefan; Möhlenkamp, Stefan; Tilgner, Andreas

2006-06-21

The pressure drop-flow relations in myocardial bridges and the assessment of vascular heart disease via fractional flow reserve (FFR) have motivated many researchers the last decades. The aim of this study is to simulate several clinical conditions present in myocardial bridges to determine the flow reserve and consequently the clinical relevance of the disease. From a fluid mechanical point of view the pathophysiological situation in myocardial bridges involves fluid flow in a time dependent flow geometry, caused by contracting cardiac muscles overlying an intramural segment of the coronary artery. These flows mostly involve flow separation and secondary motions, which are difficult to calculate and analyse. Because a three dimensional simulation of the haemodynamic conditions in myocardial bridges in a network of coronary arteries is time-consuming, we present a boundary layer model for the calculation of the pressure drop and flow separation. The approach is based on the assumption that the flow can be sufficiently well described by the interaction of an inviscid core and a viscous boundary layer. Under the assumption that the idealised flow through a constriction is given by near-equilibrium velocity profiles of the Falkner-Skan-Cooke (FSC) family, the evolution of the boundary layer is obtained by the simultaneous solution of the Falkner-Skan equation and the transient von-Kármán integral momentum equation. The model was used to investigate the relative importance of several physical parameters present in myocardial bridges. Results have been obtained for steady and unsteady flow through vessels with 0 - 85% diameter stenosis. We compare two clinical relevant cases of a myocardial bridge in the middle segment of the left anterior descending coronary artery (LAD). The pressure derived FFR of fixed and dynamic lesions has shown that the flow is less affected in the dynamic case, because the distal pressure partially recovers during re-opening of the vessel in diastole. We have further calculated the wall shear stress (WSS) distributions in addition to the location and length of the flow reversal zones in dependence on the severity of the disease. The described boundary layer method can be used to simulate frictional forces and wall shear stresses in the entrance region of vessels. Earlier models are supplemented by the viscous effects in a quasi three-dimensional vessel geometry with a prescribed wall motion. The results indicate that the translesional pressure drop and the mean FFR compares favourably to clinical findings in the literature. We have further shown that the mean FFR under the assumption of Hagen-Poiseuille flow is overestimated in developing flow conditions.

Transient integral boundary layer method to calculate the translesional pressure drop and the fractional flow reserve in myocardial bridges

PubMed Central

Bernhard, Stefan; Möhlenkamp, Stefan; Tilgner, Andreas

2006-01-01

Background The pressure drop – flow relations in myocardial bridges and the assessment of vascular heart disease via fractional flow reserve (FFR) have motivated many researchers the last decades. The aim of this study is to simulate several clinical conditions present in myocardial bridges to determine the flow reserve and consequently the clinical relevance of the disease. From a fluid mechanical point of view the pathophysiological situation in myocardial bridges involves fluid flow in a time dependent flow geometry, caused by contracting cardiac muscles overlying an intramural segment of the coronary artery. These flows mostly involve flow separation and secondary motions, which are difficult to calculate and analyse. Methods Because a three dimensional simulation of the haemodynamic conditions in myocardial bridges in a network of coronary arteries is time-consuming, we present a boundary layer model for the calculation of the pressure drop and flow separation. The approach is based on the assumption that the flow can be sufficiently well described by the interaction of an inviscid core and a viscous boundary layer. Under the assumption that the idealised flow through a constriction is given by near-equilibrium velocity profiles of the Falkner-Skan-Cooke (FSC) family, the evolution of the boundary layer is obtained by the simultaneous solution of the Falkner-Skan equation and the transient von-Kármán integral momentum equation. Results The model was used to investigate the relative importance of several physical parameters present in myocardial bridges. Results have been obtained for steady and unsteady flow through vessels with 0 – 85% diameter stenosis. We compare two clinical relevant cases of a myocardial bridge in the middle segment of the left anterior descending coronary artery (LAD). The pressure derived FFR of fixed and dynamic lesions has shown that the flow is less affected in the dynamic case, because the distal pressure partially recovers during re-opening of the vessel in diastole. We have further calculated the wall shear stress (WSS) distributions in addition to the location and length of the flow reversal zones in dependence on the severity of the disease. Conclusion The described boundary layer method can be used to simulate frictional forces and wall shear stresses in the entrance region of vessels. Earlier models are supplemented by the viscous effects in a quasi three-dimensional vessel geometry with a prescribed wall motion. The results indicate that the translesional pressure drop and the mean FFR compares favourably to clinical findings in the literature. We have further shown that the mean FFR under the assumption of Hagen-Poiseuille flow is overestimated in developing flow conditions. PMID:16790065

Surgical treatment of tricuspid valve insufficiency promotes early reverse remodeling in patients with axial-flow left ventricular assist devices.

PubMed

Maltais, Simon; Topilsky, Yan; Tchantchaleishvili, Vakhtang; McKellar, Stephen H; Durham, Lucian A; Joyce, Lyle D; Daly, Richard C; Park, Soon J

2012-06-01

The HeartMate II (Thoratec Corp, Pleasanton, Calif) continuous-flow left ventricular assist device has emerged as the standard of care for patients with advanced heart failure. The objective of this study was to assess the safety and early effectiveness of concomitant tricuspid valve procedures in patients undergoing implantation of a HeartMate II device. From February 2007 to April 2010, 83 patients underwent HeartMate II left ventricular assist device implantation. Of these, 37 patients had concomitant tricuspid valve procedures (32 repairs, 5 replacements) for severe tricuspid regurgitation. The effects of a tricuspid valve procedure on tricuspid regurgitation and right ventricular remodeling were assessed comparing echocardiographic findings at baseline and 30 days after left ventricular assist device implantation. Overall survival was also compared. Patients undergoing a concomitant tricuspid valve procedure had more tricuspid regurgitation (vena contracta, 5.6 ± 2.1 mm vs 2.9 ± 2.0 mm; P < .001), worse right ventricular dysfunction (right ventricular end-diastolic area, 33.6 ± 6.2 mm vs 31.6 ± 8.5 mm; P = .05), higher mean right atrial pressure (17.4 ± 7.1 mm Hg vs 14.9 ± 5.1 mm Hg; P = .03), and a higher Kormos score (2.6 ± 2.1 vs 1.2 ± 1.4; P = .0008) preoperatively. One month after surgery, tricuspid regurgitation was worse in patients who underwent left ventricular assist device implantation alone (+18.6%), whereas it improved significantly in patients undergoing a concomitant tricuspid valve procedure (-50.2%) (P = .005). A corresponding significant reduction in right ventricular end-diastolic area (33.6% ± 6.2% vs 30.1% ± 9.7%; P = .03) and a trend toward better right ventricular function (55.5% ± 79.7% vs 35.7% ± 60.5%; P = .28) were noted in patients undergoing a concomitant tricuspid valve procedure. Survival was comparable between the 2 groups. In patients with severe tricuspid regurgitation undergoing left ventricular assist device implantation, a concomitant tricuspid valve procedure effectively reduces tricuspid regurgitation and promotes reverse remodeling of the right ventricle. Copyright © 2012 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

The blood flow in the periodontal ligament regulated by the sympathetic and sensory nerves in the cat.

PubMed

Karita, K; Izumi, H; Tabata, T; Kuriwada, S; Sasano, T; Sanjo, D

1989-01-01

This study was carried out to investigate the nervous control of the blood flow in the periodontal ligament measured by laser Doppler flowmeter. Ten adult cats were anesthetized with pentobarbital sodium (initial dose of 30 mg/kg, i.v. and maintenance dose of 5 mg/kg, i.v.). After enucleating the left eye ball, the superior alveolar nerve was exposed. The bone overlying the labial aspect of the left maxillary canine tooth root was pared away until a transparent layer of bone was left covering the periodontal ligament. A laser light from a probe of the flowmeter fixed at the tooth was beamed through the thinned bone. Three different patterns of responses were observed following the electrical stimulation of the distal end of the cut superior alveolar nerve: an increasing, a decreasing and a biphasic change of blood flow. The application of capsaicin onto the superior alveolar nerve reduced the response of blood flow increase but had no effect on the response of blood flow decrease. On the other hand, the response of blood flow decrease was completely inhibited by the pretreatment with phentolamine while the response of blood flow increase was not affected. The present results suggest that blood flow in the periodontal ligament of cats is controlled by sympathetic alpha-adrenergic fibers for vasoconstriction and by sensory fibers for vasodilation.

Relationship between instantaneous wave-free ratio and fractional flow reserve in patients receiving hemodialysis.

PubMed

Morioka, Yuta; Arashi, Hiroyuki; Otsuki, Hisao; Yamaguchi, Junichi; Hagiwara, Nobuhisa

2017-06-22

Instantaneous wave-free ratio (iFR) is a vasodilator-free index and is reported to have a good correlation with fractional flow reserve (FFR). Hemodialysis patients exhibit left ventricular hypertrophy, reduced arterial compliance, and impaired microcirculation. Such a coronary flow condition in these patients may influence the relationship between iFR and FFR. This study assessed the impact of hemodialysis on the relationship between iFR and FFR. The study enrolled 196 patients with 265 stenoses who underwent assessment via iFR, FFR assessment, and right heart catheterization. A good correlation between iFR and FFR was observed in hemodialysis patients. iFR in the hemodialysis group was significantly lower than in the non-hemodialysis group (0.81 ± 0.13 vs. 0.86 ± 0.13, p = 0.005), although no significant difference was found in FFR and percentage diameter stenosis. An iFR value of 0.84 was found to be equivalent to an FFR value of 0.8 in hemodialysis patients, which was lower than the standard predictive iFR range for ischemia. Vasodilator-free assessment by iFR could be beneficial in evaluating intermediate coronary stenosis in patients receiving hemodialysis. However, the threshold for iFR abnormality needs adjustment in hemodialysis patients, and larger clinical trials are required to confirm the results in this specific subset.

Left-right asymmetry in the level of active Nodal protein produced in the node is translated into left-right asymmetry in the lateral plate of mouse embryos.

PubMed

Kawasumi, Aiko; Nakamura, Tetsuya; Iwai, Naomi; Yashiro, Kenta; Saijoh, Yukio; Belo, Jose Antonio; Shiratori, Hidetaka; Hamada, Hiroshi

2011-05-15

Left-right (L-R) asymmetry in the mouse embryo is generated in the node and is dependent on cilia-driven fluid flow, but how the initial asymmetry is transmitted from the node to the lateral plate has remained unknown. We have now identified a transcriptional enhancer (ANE) in the human LEFTY1 gene that exhibits marked L>R asymmetric activity in perinodal cells of the mouse embryo. Dissection of ANE revealed that it is activated in the perinodal cells on the left side by Nodal signaling, suggesting that Nodal activity in the node is asymmetric at a time when Nodal expression is symmetric. Phosphorylated Smad2/3 (pSmad2) indeed manifested an L-R asymmetric distribution at the node, being detected in perinodal cells preferentially on the left side. This asymmetry in pSmad2 distribution was found to be generated not by unidirectional transport of Nodal but rather as a result of LR distribution of active Nodal in the node is translated into the asymmetry in LPM. Copyright © 2011 Elsevier Inc. All rights reserved.

Anomalous origin of left coronary artery from pulmonary artery in older children and adults: direct aortic implantation.

PubMed

Kottayil, Brijesh P; Jayakumar, Karunakaran; Dharan, Baiju S; Pillai, Vivek V; Ajitkumar, Valaparambil; Menon, Sabarinath; Sanjay, Ganapathi

2011-02-01

Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) presents rarely in adulthood and is treated by different surgical techniques with varying results. This study was undertaken to evaluate the feasibility of reestablishment of a dual coronary system in older children and adults with emphasis on direct aortic implantation. From 2002 to 2010, 10 patients aged 10 to 51 years (median age, 24 years) underwent surgical correction of ALCAPA. Median weight was 44.5 kg. All the patients except 2 were symptomatic. Two patients were in atrial fibrillation. Eight patients had varying degrees of mitral regurgitation, which was severe in 2. In all patients, the left coronary artery was arising from the facing sinus of the pulmonary artery. Direct left main coronary implantation into the aorta was feasible in all patients. Mitral valve replacement was done in 4 patients. At a median follow-up of 5.5 years there was no new angina or infarction. One patient died 3 months postsurgery due to intracerebral bleed. Echocardiography demonstrated normal antegrade flow in the transferred left coronary artery, with 2 patients having persistent moderate mitral regurgitation. Coronary angiography done on follow-up in one patient revealed a patent transferred left coronary artery with distal development of new atherosclerotic lesion. Direct reimplantation of the ALCAPA is considered technically more difficult and hazardous in adults. With increased experience with coronary transfer technique, direct aortic implantation is feasible in adult cases. This provides a more physiologic correction and reestablishment of a dual coronary system with a better outcome. Copyright © 2011 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Hydrodynamic bifurcation in electro-osmotically driven periodic flows

NASA Astrophysics Data System (ADS)

Morozov, Alexander; Marenduzzo, Davide; Larson, Ronald G.

2018-06-01

In this paper, we report an inertial instability that occurs in electro-osmotically driven channel flows. We assume that the charge motion under the influence of an externally applied electric field is confined to a small vicinity of the channel walls that, effectively, drives a bulk flow through a prescribed slip velocity at the boundaries. Here, we study spatially periodic wall velocity modulations in a two-dimensional straight channel numerically. At low slip velocities, the bulk flow consists of a set of vortices along each wall that are left-right symmetric, while at sufficiently high slip velocities, this flow loses its stability through a supercritical bifurcation. Surprisingly, the flow state that bifurcates from a left-right symmetric base flow has a rather strong mean component along the channel, which is similar to pressure-driven velocity profiles. The instability sets in at rather small Reynolds numbers of about 20-30, and we discuss its potential applications in microfluidic devices.

Cardiac beta-adrenergic receptors and coronary hemodynamics in the conscious dog during hypoxic hypoxia.

NASA Technical Reports Server (NTRS)

Erickson, H. H.; Stone, H. L.

1972-01-01

The mechanisms by which acute hypoxia (10% and 5% oxygen) mediates changes in coronary blood flow and cardiac function were investigated in the conscious dog. When the dogs breathed hypoxic gas mixtures through a tracheostomy, both arterial and coronary sinus oxygen tensions were significantly decreased. With 5% oxygen, there were significant increases in heart rate (25%), maximum left ventricular dP/dt (39%), left circumflex coronary artery blood flow (163%), and left ventricular oxygen consumption (52%), which were attenuated by beta-adrenergic blockage with propranolol. When electrical pacing was used to keep the ventricular rate constant during hypoxia, there was no significant difference in coronary blood flow before and after beta blockade. Beta-adrenergic receptor activity in the myocardium participates in the integrated response to hypoxia although it may not cause active vasodilation of the coronary vessels.

Second diastolic pulmonary venous flow and isolated late diastolic mitral valve regurgitation in first-degree atrioventricular block.

PubMed

Leibundgut, Gregor; Bernheim, Alain M

2010-04-01

The authors report the case of a 77-year-old male patient with sinus rhythm and a first-degree atrioventricular (AV) block who was referred for echocardiographic follow-up 18 years after aortic valve replacement. Left ventricular systolic function as well as the function of the aortic prosthesis was normal. Systolic mitral regurgitation (MR) was virtually absent, but isolated late diastolic MR was detected by colour Doppler imaging. Coincidental to the occurrence of diastolic MR, a second late diastolic forward flow in the pulmonary veins was observed. Therefore, during the prolonged left atrial relaxation caused by first-degree AV block, the left atrial pressure drops below the pressure in both adjacent chambers in late diastole, resulting in both late diastolic MR and a second diastolic pulmonary venous forward flow.

Surviving catastrophic disintegration of a large left atrial myxoma: the importance of multi-disciplinary team.

PubMed

Habbab, Louay; Alfaraidi, Haifa; Lamy, Andre

2014-09-12

Atrial myxomas are the most common primary cardiac tumors, representing ∼50% of all benign cardiac tumors. Patients with a left atrial myxoma (LAM) generally present with symptoms of mechanical obstruction of blood flow, systemic emboli or constitutional symptoms. Embolic complications may occur any time with progression of the tumor; therefore, myxoma is usually considered an indication for urgent surgery. This report describes a patient with mobile large LAM who survived multiple emboli to the brain, spleen, kidneys, abdominal aorta and lower limbs during hospitalization for surgery, illustrating the critical nature of this finding and its possible catastrophic complications and demonstrating the importance of multi-disciplinary team in the decision-making process and the management of such complications and supporting the hypothesis that intravenous thrombolysis may be safely used in the treatment of embolic stroke due to cardiac myxoma. Published by Oxford University Press and JSCR Publishing Ltd. All rights reserved. © The Author 2014.

Effects of coil closure of patent ductus arteriosus on left anterior descending coronary artery blood flow using transthoracic Doppler echocardiography.

PubMed

Harada, Kenji; Toyono, Manotomo; Tamura, Masamichi

2004-06-01

Transthoracic Doppler echocardiography provides noninvasive measurements of coronary blood flow in the left anterior descending coronary artery (LAD). This method has the potential to show the effects of acute changes in loading conditions on blood flow. Coil closure of patent ductus arteriosus (PDA) is a model of acute changes in blood pressure and left ventricular (LV) preload that influences coronary blood flow. We applied this technique to assess the coronary blood flow changes for patients with PDA before and immediately after PDA coil closure. We examined 9 patients (1.8 +/- 1.1 years) with simple PDA and 8 age-matched healthy children. LV dimensions and LV mass were measured. Maximum peak flow velocity and flow volume in the LAD were measured. Pulmonary to systemic flow ratios (Qp/Qs) were obtained by cardiac catheterization. After PDA coil closure, LV end-diastolic dimension decreased, and systolic and diastolic blood pressures increased significantly. The maximum peak flow velocity, LAD flow volume, and the ratio of LAD flow volume to LV mass increased significantly. The changes in maximum peak flow velocity and the ratio of LAD flow volume to LV mass (F/M) correlated positively with the changes in diastolic pressure and Qp/Qs. In 5 patients who had Qp/Qs > 1.5, the mean F/M was significantly lower compared with control subjects, but they increased to normal values after coil closure of PDA. PDA coil closure increases diastolic pressure and decreases Qp/Qs, resulting in improvement of myocardial perfusion. These findings provide new insights into the relationship between cardiac function and coronary circulation in pediatric patients with heart diseases associated with PDA.

Water Reserves Program. An adaptation strategy to prevent imbalance of water in nature

NASA Astrophysics Data System (ADS)

Salinas-Rodriguez, S. A.; López Pérez, M.; Barrios Ordóñez, J.; Wickel, B.; Villón Bracamonte, R. A.

2013-12-01

Freshwater ecosystems occupy approximately 1% of the earth's surface yet possess about 12% of all known animal species. By virtue of their position in the landscape they connect terrestrial and coastal marine biomes and provide and sustain ecosystem services vital to the health and persistence of human communities. These services include the supply of water for food production, urban and industrial consumption, among others. Over the past century many freshwater ecosystems around the world have been heavily modified or lost due to the alteration of flow regimes (e.g. damming, canalization, diversion, over-abstraction). The synergistic impacts of land use change, changes in flows, chemical deterioration, and climate change have left many systems and their species very little room to adjust to change, while future projections indicate a steady increase imbalance in water demand for food and energy production and water supply to suit the needs of a growing world population. In Mexico, the focus has been to secure water for human development and maximize economic growth, which has resulted in allocation of water beyond available amounts, and that in many river basins has led imbalance of water in nature. As a consequence episodic water scarcity severely constrains freshwater ecosystems and the services they provide. Climatic change and variability are presenting serious challenges to a country that already is experiencing serious strain on its water resources. However, freshwater ecosystems are recognized by law as legitimate user of water, and mandate a flow allocation for the environment ('water reserve' or 'environmental flows'). Based on this legal provision the Mexican government through the National Water Commission (Conagua), with support of the Alliance WWF - Fundación Gonzalo Río Arronte, and the Interamerican Development Bank, has launched a national program to identify and implement 'water reserves': basins where environmental flows will be secured and allocated, and where the flow regime is then protected before over-allocation takes place. The strategy has been to identify and protect basins with an availability of water that is close to their natural flow regime and that also have a high conservation value (based on prior national conservation priority definitions such as protected areas, and biodiversity conservation gap analyses) in order to implement legal restrictions on water resource development. With such protection, these systems will be best positioned to adjust and respond to water shortages, and regime shifts. To date, 189 basins around the country were identified as potential water reserves. The next step will be the nomination of these water reserves to be integrated in the National Water Reserves Program. This program forms the core of the official Mexican government adaptation strategy towards climate prepared water management, which recognizes that water reserves are the buffer society needs to face uncertainty, imbalance of the man-made, global changes, and thus to reduce water scarcity risk. The development of activities that alter the natural flow regime such as dams and levees are closely examined, and would potentially be restricted.

Low regional cerebral blood flow in burning mouth syndrome patients with depression.

PubMed

Liu, B-L; Yao, H; Zheng, X-J; Du, G-H; Shen, X-M; Zhou, Y-M; Tang, G-Y

2015-07-01

The main aims of this study were to (i) investigate the emotional disorder status of patients with burning mouth syndrome (BMS) and (ii) detect regional cerebral blood flow in BMS patients with the application of combined single-photon emission computed tomography and computed tomography (SPECT/CT). The degree of pain was measured using the visual analysis scale, and emotional disorder with the self-rating anxiety scale, self-rating depression scale, and Hamilton depression rating scale in 29 patients with BMS and 10 healthy controls. SPECT/CT was performed in 29 patients with BMS and 10 healthy controls, and statistical parametric mapping method was used for between-group analyses. The incidence rate of depression in patients with BMS was 31.0%. Compared to the control group, patients with BMS displayed significantly different depression and anxiety scales (P < 0.05). Significantly lower regional cerebral blood flow in the left parietal and left temporal lobes was recorded for BMS patients with depression (P < 0.05). Patients with BMS experience more depression and anxious emotion. Moreover, depression in patients with BMS may be associated with lower regional cerebral blood flow in the left temporal and left parietal lobes. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

The effect of acute mechanical left ventricular unloading on ovine tricuspid annular size and geometry.

PubMed

Malinowski, Marcin; Wilton, Penny; Khaghani, Asghar; Brown, Michael; Langholz, David; Hooker, Victoria; Eberhart, Lenora; Hooker, Robert L; Timek, Tomasz A

2016-09-01

Left ventricular assist device (LVAD) implantation may alter right ventricular shape and function and lead to tricuspid regurgitation. This in turn has been reported to be a determinant of right ventricular (RV) failure after LVAD implantation, but the effect of mechanical left ventricular (LV) unloading on the tricuspid annulus is unknown. The aim of the study was to provide insight into the effect of LVAD support on tricuspid annular geometry and dynamics that may help to optimize LV unloading with the least deleterious effect on the right-sided geometry. In seven open-chest anaesthetized sheep, nine sonomicrometry crystals were implanted on the right ventricle. Additional nine crystals were implanted around the tricuspid annulus, with one crystal at each commissure defining three separate annular regions: anterior, posterior and septal. Left ventricular unloading was achieved by connecting a cannula in the left atrium and the aorta to a continuous-flow pump. The pump was used for 15 min at a full flow of 3.8 ± 0.3 l/min. Epicardial echocardiography was used to assess the degree of tricuspid insufficiency. Haemodynamic, echocardiographic and sonomicrometry data were collected before and during full unloading. Tricuspid annular area, and the regional and total perimeter were calculated from crystal coordinates, while 3D annular geometry was expressed as the orthogonal distance of each annular crystal to the least squares plane of all annular crystals. There was no significant tricuspid regurgitation observed either before or during LV unloading. Right ventricular free wall to septum diameter increased significantly at end-diastole during unloading from 23.6 ± 5.8 to 26.3 ± 6.5 mm (P = 0.009), but the right ventricular volume, tricuspid annular area and total perimeter did not change from baseline. However, the septal part of the annulus significantly decreased its maximal length (38.6 ± 8.1 to 37.9 ± 8.2 mm, P = 0.03). Annular contraction was not altered. The tricuspid annulus had a complex 3D saddle-shaped geometry that was unaffected during experimental conditions. In healthy sheep hearts, left ventricular unloading increased septal-free wall RV diameter and reduced the length of the septal annulus, without altering the motion or geometry of the tricuspid annulus. Acute left ventricular unloading alone in healthy sheep was not sufficient to significantly perturb tricuspid annular dynamics and result in tricuspid insufficiency. © The Author 2016. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

On the relationship between competitive flow and FFT analysis of the flow waves in the left internal mammary artery graft in the process of CABG.

PubMed

Mao, Boyan; Wang, Wenxin; Zhao, Zhou; Zhao, Xi; Li, Lanlan; Zhang, Huixia; Liu, Youjun

2016-12-28

During coronary artery bypass grafting (CABG), the ratio of powers of the fundamental frequency and its first harmonic (F0/H1) in fast Fourier transformation (FFT) analysis of the graft's flow waves has been used in the field of evaluation of the patency in anastomosis. But there is no report about using the FFT method to evaluate the magnitude of competitive flow. This study is aiming at exploring the relationship between competitive flow and FFT analysis of the flow waves in left internal mammary artery (LIMA) graft, and finding a new method to evaluate the magnitude of competitive flow. At first, establishing the CABG multiscale models of different stenosis in left anterior descending artery (LAD) to get different magnitude of competitive flows. Then, calculating the models by ANSYS-CFX and getting the flow waves in LIMA. Finally, analyzing the flow waves by FFT method and comparing the FFT results with the magnitude of competitive flow. There is no relationship between competitive flow and F0/H1. As for F0/H2 and F0/H3, they both increase with the reduction of the stenosis in LAD. But the increase of F0/H3 is not obviously enough and it can't identify the significant competitive flow clearly, so it can't be used as the evaluation index. It is found that F0/H2 increases obviously with the increase of the competitive flow and can identify the significant competitive flow. The FFT method can be used in the evaluation of competitive flow and the F0/H2 is the ideal index. High F0/H2 refers to the significant competitive flow. This method can be used during CABG to avoid the risk of competitive flow.

Intraatrial baffle repair of isolated ventricular inversion with left atrial isomerism.

PubMed

McElhinney, D B; Reddy, V M; Silverman, N H; Hanley, F L

1996-11-01

Isolated ventricular inversion with left atrial isomerism, partial anomalous pulmonary venous connection, and interruption of the inferior vena cava with azygos continuation to a right superior vena cava was diagnosed by echocardiography in a neonate. At 48 days of age, the patient underwent successful anatomic correction with redirection of flow from the superior vena cava and hepatic veins to the left-sided tricuspid valve, and flow from the pulmonary veins to the right-sided mitral valve. In the present report, the surgical techniques of this case are described, along with a survey of the surgical literature covering anatomic repair of isolated ventricular inversion.

Normal flow signal of the pterygoid plexus on 3T MRA in patients without DAVF of the cavernous sinus.

PubMed

Watanabe, K; Kakeda, S; Watanabe, R; Ohnari, N; Korogi, Y

2013-01-01

Cavernous sinuses and draining dural sinuses or veins are often visualized on 3D TOF MRA images in patients with dural arteriovenous fistulas involving the CS. Flow signals may be seen in the jugular vein and dural sinuses at the skull base on MRA images in healthy participants, however, because of reverse flow. Our purpose was to investigate the prevalence of flow signals in the pterygoid plexus and CS on 3T MRA images in a cohort of participants without DAVFs. Two radiologists evaluated the flow signals of the PP and CS on 3T MRA images obtained from 406 consecutive participants by using a 5-point scale. In addition, the findings on 3T MRA images were compared with those on digital subtraction angiography images in an additional 171 participants who underwent both examinations. The radiologists identified 110 participants (27.1%; 108 left, 10 right, 8 bilateral) with evidence of flow signals in the PP alone (n = 67) or in both the PP and CS (n = 43). Flow signals were significantly more common in the left PP than in the right PP. In 171 patients who underwent both MRA and DSA, the MRA images showed flow signals in the PP with or without CS in 60 patients; no DAVFs were identified on DSA in any of these patients. Flow signals are frequently seen in the left PP on 3T MRA images in healthy participants. This finding may be the result of flow reversal and should not be considered to indicate occult DAVF.

Enhancement of Arterial Pressure Pulsatility by Controlling Continuous-Flow Left Ventricular Assist Device Flow Rate in Mock Circulatory System.

PubMed

Bozkurt, Selim; van de Vosse, Frans N; Rutten, Marcel C M

Continuous-flow left ventricular assist devices (CF-LVADs) generally operate at a constant speed, which reduces pulsatility in the arteries and may lead to complications such as functional changes in the vascular system, gastrointestinal bleeding, or both. The purpose of this study is to increase the arterial pulse pressure and pulsatility by controlling the CF-LVAD flow rate. A MicroMed DeBakey pump was used as the CF-LVAD. A model simulating the flow rate through the aortic valve was used as a reference model to drive the pump. A mock circulation containing two synchronized servomotor-operated piston pumps acting as left and right ventricles was used as a circulatory system. Proportional-integral control was used as the control method. First, the CF-LVAD was operated at a constant speed. With pulsatile-speed CF-LVAD assistance, the pump was driven such that the same mean pump output was generated. Continuous and pulsatile-speed CF-LVAD assistance provided the same mean arterial pressure and flow rate, while the index of pulsatility increased significantly for both arterial pressure and pump flow rate signals under pulsatile speed pump support. This study shows the possibility of improving the pulsatility of CF-LVAD support by regulating pump speed over a cardiac cycle without reducing the overall level of support.

Computational Fluid Dynamics Analysis of the Effect of Plaques in the Left Coronary Artery

PubMed Central

Chaichana, Thanapong; Sun, Zhonghua; Jewkes, James

2012-01-01

This study was to investigate the hemodynamic effect of simulated plaques in left coronary artery models, which were generated from a sample patient's data. Plaques were simulated and placed at the left main stem and the left anterior descending (LAD) to produce at least 60% coronary stenosis. Computational fluid dynamics analysis was performed to simulate realistic physiological conditions that reflect the in vivo cardiac hemodynamics, and comparison of wall shear stress (WSS) between Newtonian and non-Newtonian fluid models was performed. The pressure gradient (PSG) and flow velocities in the left coronary artery were measured and compared in the left coronary models with and without presence of plaques during cardiac cycle. Our results showed that the highest PSG was observed in stenotic regions caused by the plaques. Low flow velocity areas were found at postplaque locations in the left circumflex, LAD, and bifurcation. WSS at the stenotic locations was similar between the non-Newtonian and Newtonian models although some more details were observed with non-Newtonian model. There is a direct correlation between coronary plaques and subsequent hemodynamic changes, based on the simulation of plaques in the realistic coronary models. PMID:22400051

Keep-Left Behavior Induced by Asymmetrically Profiled Walls

NASA Astrophysics Data System (ADS)

Oliveira, C. L. N.; Vieira, A. P.; Helbing, D.; Andrade, J. S.; Herrmann, H. J.

2016-01-01

We show, computationally and analytically, that asymmetrically shaped walls can organize the flow of pedestrians driven in opposite directions through a corridor. Precisely, a two-lane ordered state emerges in which people always walk on the left-hand side (or right-hand side), controlled by the system's parameters. This effect depends on features of the channel geometry, such as the asymmetry of the profile and the channel width, as well as on the density and the drift velocity of pedestrians, and the intensity of noise. We investigate in detail the influence of these parameters on the flow and discover a crossover between ordered and disordered states. Our results show that an ordered state only appears within a limited range of drift velocities. Moreover, increasing noise may suppress such flow organization, but the flow is always sustained. This is in contrast with the "freezing by heating" phenomenon according to which pedestrians tend to clog in smooth channels for strong noise [Phys. Rev. Lett. 84, 1240 (2000)]. Therefore, the ratchetlike effect proposed here acts on the system not only to induce a "keep-left" behavior but also to prevent the freezing by heating clogging phenomenon. Besides pedestrian flow, this new phenomenon has other potential applications in microfluidics systems.

Regional pulmonary blood flow measurement in humans with electron-beam computed tomography

NASA Astrophysics Data System (ADS)

Holt, William W.; Konhilas, John; Wolfkiel, Christopher J.

1995-05-01

Electron beam computed tomography (EBCT) is a potentially useful modality to quantitate regional pulmonary flow (RPF) with minimal invasiveness, in part because it has good spatial and temporal resolution. The present studies used a single compartment model of indicator transport and EBCT to measure regional tissue flow in the lungs of human subjects. The model postulates that flow is proportional to maximal enhancement and assumes complete tissue accumulation of indicator before significant indicator washout (WO). EBCT flow studies were retrospectively analyzed with respect to RPF in 10 adult patients who had undergone clinically indicated or research cardiovascular studies. Time density curves from the left atrial (LA) cavity and one-third segments of left (LL) and right (RL) lungs (A: anterior, M: middle, and P: posterior segments) were used to calculate RPF. Washout was determined as the percent of the LA curve at the time of peak parenchymal opacification using gamma curve fits to both tissue data and the LA curve data. Mean +/- standard deviation RPF in ml/min/ml was 0.8 +/- 0.4, 1.1 +/- 0.4, and 1.3 +/- 0.4 for A, M, and P respectively for one-third regions in the left lung. Similar results were found in the right lung. No difference in RPF was found when images were measured either by including the largest of visible parenchymal vessels or when such vessels were excluded. Flow in A of LL and RL was less than that in M or P. Average WO was about 10%, with a range of 0-41% of the LA curve area. There was no significant difference between one-third segment WO using pairwise comparison on the left and right sides when tested separately. RPF values were greater in the posterior vs anterior regions of these supine patients. In conclusion, EBCT can detect gravity related flow differences in the human lung. EBCT has potential for clinical assessment of absolute regional pulmonary flow determination in animals and man.

[Evaluation of left ventricular diastolic function in canine acute myocardial ischemia using velocity vector imaging and quantitative tissue velocity imaging].

PubMed

Zhang, Chuan; Zha, Dao-Gang; DU, Rong-Sheng; Hu, Feng; Li, Sheng-Hui; Wu, Xiao-Yuan; Liu, Yi-Li

2009-07-01

To assess the value of velocity vector imaging (VVI) and quantitative tissue velocity imaging (QTVI) in assessing left ventricular diastolic function of the dogs with acute myocardial ischemia. Six healthy mongrel dogs were subjected to ligation of the left circumflex artery or left anterior descending artery to induce coronary artery stenosis of varying degrees. The mean peak diastolic velocity (Em) of the ventricular walls around the mitral annulus was recorded with VVI or QTVI in the coronary blood flow. The left ventricular end diastolic pressure (LVEDP) was measured with pigtail catheter in the left ventricle. As the coronary blood flow decreased, LVEDP was gradually increased, and Em measured by VVI or QTVI were also gradually decreased. A good linear correlation was shown between Em measured by VVI or QTVI and LVEDP (r=-0.834, P<0.001, and r=-0.68, P<0.001, respectively). A significant difference was observed in the correlation coefficient between VVI and QTVI (Z=2.625, P=0.0087). VVI and QTVI both provide good noninvasive means for measuring left ventricular diastolic function. VVI, a new echocardiographic modality without angular dependence, is better than QTVI in evaluating left ventricular diastolic function.

Influence of polymeric microspheres on the myocardial oxygen partial pressure in the beating heart of pigs.

PubMed

Hiebl, B; Mrowietz, C; Lee, S; Braune, S; Knaut, M; Lendlein, A; Franke, R P; Jung, F

2011-07-01

Injection of labeled microspheres is an established method in animal models to analyze the capillary organ blood flow at different time points. However, the microspheres can lead to stenoses of the capillary lumen, which might affect tissue oxygen supply. Our study aimed to investigate the influence of repeated injections of microspheres into the left coronary artery on the tissue oxygen partial pressure (pO(2)) in the downstream supplied myocardium of Göttingen minipigs. Tests (n=6 pigs each) were performed with two differently sized microspheres (ø=10 ± 0.1 μm (M10) or ø=15 ± 0.15 μm (M15)) from polystyrene. The pO(2) was measured in the midmyocardium of the left and right ventricle for 6 min continuously after each of five injections (1 × 10(6) microspheres each). There was a time laps of 12 min between each injection. In addition, the influence of the carrier solution was analyzed solely in the identical time frame. pO(2) decreased significantly in the myocardial area supplied by the ramus interventricularis paraconalis after injection of M15 microspheres. In contrast, the application of the M10 microspheres did not change the myocardial pO(2). This finding suggests to use microspheres with diameters not exceeding 10 μm for the coronary blood flow assessment. Copyright © 2011 Elsevier Inc. All rights reserved.

Outcomes for Patients With Diabetes After Continuous-Flow Left Ventricular Assist Device Implantation.

PubMed

Vest, Amanda R; Mistak, Stanley M; Hachamovitch, Rory; Mountis, Maria M; Moazami, Nader; Young, James B

2016-10-01

Diabetes mellitus (DM) is a risk factor for mortality among patients with heart failure as well as for patients who undergo cardiothoracic surgery. However it is unknown whether DM is associated with increased mortality or major complications during continuous-flow left ventricular assist device (CF-LVAD) support. We retrospectively reviewed 300 consecutive adults who received CF-LVADs at a single center in the years 2006-2013; 129 patients had DM before LVAD, as defined by American Diabetes Association criteria (HbA1c ≥6.5% and/or taking DM medications). Compared with the non-DM group, DM patients were older, with a higher pre-LVAD body mass index, more ischemic heart failure etiology, and higher pre-LVAD creatinine. Ninety-three patients died on LVAD support, 43 with DM and 50 without DM (P = .4526). After control for 9 covariates in a Cox proportional hazards model, DM was unassociated with all-cause mortality (hazard ratio 0.883, 95% confidence interval 0.571-1.366; P = .5768). Diabetes was also unassociated with the adverse event end points of stroke/transient ischemic attack, intracerebral hemorrhage, pump thrombosis, and device-related infections. Diabetes is common in LVAD recipients (43% of the present cohort) but does not increase mortality or rates of major adverse events during CF-LVAD support. Copyright © 2016 Elsevier Inc. All rights reserved.

Can regurgitant flow damage the left atrial endothelium in patients with prosthetic mechanical heart valves?

PubMed

Milo, Simcha; Zarandi, Mehrdad; Gutfinger, Chaim; Gharib, Morteza

2005-05-01

Previous in-vitro studies of mechanical heart valves (MHVs) in the closed position demonstrated the formation of regurgitant flows, with bubbles and jets forming vortices during each systole. The study aim was to determine whether the regurgitant flow observed in patients with MHVs can damage the left atrial endothelium, due to shear stresses exerted on the endothelial layers. This objective has been accomplished by appropriate in-vitro simulation experiments. In these experiments, leakage flow through several commercial MHVs was investigated. The geometry of the set-up closely resembled that of the left atrial anatomy. Water was forced through the slit of a closed MHV and directed toward the hemispherical cup coated with fluorescent paint. The flow field between the valve and the cup was photographed using high-speed videography, from which local velocities were measured, using digital particle imaging velocimetry. Qualitative damage to the surface of the cup was assessed from the amount of fluorescent paint removed from the cup. The experimental results and calculations indicated that flows through the gaps of the closed valves were sufficient to generate strong vortices, with velocities near the atrial wall in the range of 0.5 to 4.0 m/s, depending on the valve. This led to high shear stresses on the left atrial wall, which far exceeded physiologically acceptable levels. The calculated shear stresses exceeded by orders of magnitude the maximum physiologically tolerated stresses. This suggests that shear stresses associated with regurgitant jets in MHVs may damage the endothelial cells, leading to the activation of the inflammatory reaction, enhanced procoagulation, platelet activation and aggregation, and mechanical cell denudation.

Pulsatile flows and wall-shear stresses in models simulating normal and stenosed aortic arches

NASA Astrophysics Data System (ADS)

Huang, Rong Fung; Yang, Ten-Fang; Lan, Y.-K.

2010-03-01

Pulsatile aqueous glycerol solution flows in the models simulating normal and stenosed human aortic arches are measured by means of particle image velocimetry. Three transparent models were used: normal, 25% stenosed, and 50% stenosed aortic arches. The Womersley parameter, Dean number, and time-averaged Reynolds number are 17.31, 725, and 1,081, respectively. The Reynolds numbers based on the peak velocities of the normal, 25% stenosed, and 50% stenosed aortic arches are 2,484, 3,456, and 3,931, respectively. The study presents the temporal/spatial evolution processes of the flow pattern, velocity distribution, and wall-shear stress during the systolic and diastolic phases. It is found that the flow pattern evolving in the central plane of normal and stenosed aortic arches exhibits (1) a separation bubble around the inner arch, (2) a recirculation vortex around the outer arch wall upstream of the junction of the brachiocephalic artery, (3) an accelerated main stream around the outer arch wall near the junctions of the left carotid and the left subclavian arteries, and (4) the vortices around the entrances of the three main branches. The study identifies and discusses the reasons for the flow physics’ contribution to the formation of these features. The oscillating wall-shear stress distributions are closely related to the featured flow structures. On the outer wall of normal and slightly stenosed aortas, large wall-shear stresses appear in the regions upstream of the junction of the brachiocephalic artery as well as the corner near the junctions of the left carotid artery and the left subclavian artery. On the inner wall, the largest wall-shear stress appears in the region where the boundary layer separates.

Evaluation of lymph flow patterns in splenic flexural colon cancers using laparoscopic real-time indocyanine green fluorescence imaging.

PubMed

Watanabe, Jun; Ota, Mitsuyoshi; Suwa, Yusuke; Ishibe, Atsushi; Masui, Hidenobu; Nagahori, Kaoru

2017-02-01

The treatment of splenic flexural colon cancer is not standardized because the lymphatic drainage is variable. The aim of this study is to evaluate the lymph flow at the splenic flexure. From July 2013 to January 2016, consecutive patients of the splenic flexural colon cancer with a preoperative diagnosis of N0 who underwent laparoscopic surgery were enrolled. Primary outcome is frequency of the direction of lymph flow from splenic flexure. We injected indocyanine green (2.5 mg) into the submucosal layer around the tumor and observed lymph flow using the laparoscopic near-infrared camera system in 30 min after injection. Thirty-one patients were enrolled in this study. The lymph flow was visualized in 31 patients (100 %) without any complications. No case exhibited lymph flow in both the left colic artery (LCA) and left branch of the middle colic artery (lt-MCA) areas. There were 19 cases (61.3 %) with lymph flow directed to the area of the root of the inferior mesenteric vein (IMV), regardless of the presence of the left accessory aberrant colic artery. Lymph node metastases were observed in six cases (19.4 %), and all of the involved lymph nodes existed in lymph flow areas determined by real-time indocyanine green fluorescence imaging. The findings of the lymph flow pattern of splenic flexure suggest that lymph node dissection at the root of the IMV area is important, and it may be not necessary to ligate both the lt-MCA and LCA, at least in cases without widespread lymph node metastases.

Computational fluid dynamics analysis of a maglev centrifugal left ventricular assist device.

PubMed

Burgreen, Greg W; Loree, Howard M; Bourque, Kevin; Dague, Charles; Poirier, Victor L; Farrar, David; Hampton, Edward; Wu, Z Jon; Gempp, Thomas M; Schöb, Reto

2004-10-01

The fluid dynamics of the Thoratec HeartMate III (Thoratec Corp., Pleasanton, CA, U.S.A.) left ventricular assist device are analyzed over a range of physiological operating conditions. The HeartMate III is a centrifugal flow pump with a magnetically suspended rotor. The complete pump was analyzed using computational fluid dynamics (CFD) analysis and experimental particle imaging flow visualization (PIFV). A comparison of CFD predictions to experimental imaging shows good agreement. Both CFD and experimental PIFV confirmed well-behaved flow fields in the main components of the HeartMate III pump: inlet, volute, and outlet. The HeartMate III is shown to exhibit clean flow features and good surface washing across its entire operating range.

Effective use of flow-spoiled FBI and time-SLIP methods in the diagnostic study of an aberrant vessel of the head and neck: "left jugular venous steal by the right jugular vein".

PubMed

Kogure, Taroh; Kogure, Kyuya; Iizuka, Mitsumasa; Ino, Azusa; Ishii, Masako

2010-08-01

Three-dimensional (3D) time-of-flight (TOF) is now commonly used in routine magnetic resonance angiography (MRA) studies of the head and neck. However, there are limits to its diagnostic abilities in the clinical field and, in some instances, a more invasive supplementary examination may be required. We incidentally discovered a patient with an aberrant vessel of the head and neck that ran alongside the left carotid artery and contained a constant, slowly pulsating efferent blood flow. 3D-TOF and carotid ultrasonography could not determine the nature and origin of this vessel. Additional studies using flow-spoiled fresh blood imaging (flow-spoiled FBI) and time spatial labeling inversion pulse (time-SLIP) methods were effective in determining that the vessel was the left jugular vein, and that the continuous venous reflux was a result of a venous steal by the right jugular vein. We show that by combining different MRA techniques we can effectively achieve diagnosis without resorting to more invasive examinations. 2010 Wiley-Liss, Inc.

Fluid dynamics model of mitral valve flow: description with in vitro validation.

PubMed

Thomas, J D; Weyman, A E

1989-01-01

A lumped variable fluid dynamics model of mitral valve blood flow is described that is applicable to both Doppler echocardiography and invasive hemodynamic measurement. Given left atrial and ventricular compliance, initial pressures and mitral valve impedance, the model predicts the time course of mitral flow and atrial and ventricular pressure. The predictions of this mathematic formulation have been tested in an in vitro analog of the left heart in which mitral valve area and atrial and ventricular compliance can be accurately controlled. For the situation of constant chamber compliance, transmitral gradient is predicted to decay as a parabolic curve, and this has been confirmed in the in vitro model with r greater than 0.99 in all cases for a range of orifice area from 0.3 to 3.0 cm2, initial pressure gradient from 2.4 to 14.2 mm Hg and net chamber compliance from 16 to 29 cc/mm Hg. This mathematic formulation of transmitral flow should help to unify the Doppler echocardiographic and catheterization assessment of mitral stenosis and left ventricular diastolic dysfunction.

A D-Shaped Bileaflet Bioprosthesis which Replicates Physiological Left Ventricular Flow Patterns

PubMed Central

Tan, Sean Guo-Dong; Kim, Sangho; Hon, Jimmy Kim Fatt; Leo, Hwa Liang

2016-01-01

Prior studies have shown that in a healthy heart, there exist a large asymmetric vortex structure that aids in establishing a steady flow field in the left ventricle. However, the implantation of existing artificial heart valves at the mitral position is found to have a negative effect on this physiological flow pattern. In light of this, a novel D-shaped bileaflet porcine bioprosthesis (GD valve) has been designed based on the native geometry mitral valve, with the hypothesis that biomimicry in valve design can restore physiological left ventricle flow patterns after valve implantation. An in-vitro experiment using two dimensional particle velocimetry imaging was carried out to determine the hemodynamic performance of the new bileaflet design and then compared to that of the well-established St. Jude Epic valve which functioned as a control in the experiment. Although both valves were found to have similar Reynolds shear stress and Turbulent Kinetic Energy levels, the novel D-shape valve was found to have lower turbulence intensity and greater mean kinetic energy conservation. PMID:27258099

Map Showing Quaternary Geology and Geomorphology of the Granite Park Area, Grand Canyon, Arizona

USGS Publications Warehouse

Hereford, Richard; Burke, Kelly J.; Thompson, Kathryn S.

2000-01-01

View to west-northwest showing map area and setting of Granite Park; Grand Canyon, Arizona. The Colorado River flows from right to left. Granite Park Wash is the light-colored area in foreground of photograph. The debris fan of 209 Mile Canyon is at left center. Pleistocene gravel is exposed in the steep, light-colored bank above 209 Mile Rapids at left edge of photograph. The black-colored ledge that forms the dark cliff at upper right of photograph is the basalt flow of Hamblin (1994). Sand dunes, debris fans, and terraces of the Colorado River cover the lower half of this area shown in this photograph.

Echocardiographic assessment of left ventricular diastolic function.

PubMed

Pirat, Bahar; Zoghbi, William A

2007-09-01

Assessment of diastolic function and left ventricular filling pressures in the setting of both normal and reduced systolic function is of major importance particularly in patients with dyspnea. Since multiple echocardiography parameters are used to assess diastolic function each with some limitations, a comprehensive approach should be applied. Transmitral Doppler flow should be evaluated in combination with newer, less load dependent Doppler techniques. Tissue Doppler imaging provides accurate, well validated data regarding diastolic properties and filling pressures of the left ventricle. Tissue Doppler imaging should be the part of a routine echocardiography study due to its ease of use and high reproducibility. Pulmonary vein Doppler and flow propagation velocity should be incorporated into the evaluation when needed.

Left ventricular aneurysms in hypertrophic cardiomyopathy with midventricular obstruction: A systematic review of literature.

PubMed

Elsheshtawy, Moustafa O; Mahmoud, Ahmed N; Abdelghany, Mahmoud; Suen, Ida H; Sadiq, Adnan; Shani, Jacob

2018-05-22

Hypertrophic cardiomyopathy (HCM) with or without left ventricular apical aneurysm (LVA) had been studied in the past. Midventricular obstruction associated with HCM and LVA is a unique entity that has not been distinguished previously as a separate phenotypic disease in HCM patients. A systematic review of Pubmed and Google Scholar was conducted from inception until September 2017 for all observational studies conducted on HCM with midventricular obstruction and LVA. A total of 94 patients from 39 studies were included in our analysis. The mean age of the patients was 58.05 ± 11.76 years with 59.6% being males. The most common electrocardiographic finding was T wave inversion occurring in 13.8% of the cases followed by ST elevation (9.5%). Maximal left ventricle (LV) wall thickness was reported 18.89 ± 5.19 mm on transthoracic echocardiography and paradoxical Jet flow was detected in 29.8% of patients. Beta-blockers (58.5%) were the most common drug therapy at baseline and amiodarone (10.6%) was the most common antiarrhythmic used for ventricular tachycardia (VT). The most common complication, ventricular tachycardia, occurred in 39.3% of cases and the incidence of all-cause mortality was 13.8 % over 16 ± 20.1 months follow-up. Implantable cardioverter defibrillator was used in 37.2% of patients with 25.7% of patients with ICD received appropriate shock therapy. HCM with LVA and midventricular obstruction is a unique entity that appears to be associated with high incidence of morbidity and mortality. Thus, early diagnosis and therapeutic intervention is recommended for management of this condition. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Evaluation of optic nerve head blood flow in normal rats and a rodent model of non-arteritic ischemic optic neuropathy using laser speckle flowgraphy.

PubMed

Takako, Hidaka; Hideki, Chuman; Nobuhisa, Nao-I

2017-10-01

To evaluate optic nerve head (ONH) blood flow in normal rats and a rodent model of non-arteritic ischemic optic neuropathy (rNAION) in vivo using laser speckle flowgraphy (LSFG). Rats were under general anesthesia; to induce NAION, Rose Bengal (RB) was injected into the tail vein. After the administration of RB, the left ONH was photoactivated using an argon green laser. We measured ONH blood flow in the normal rats and the rNAION group (at 1, 3, 7, 14, and 28 days after the induction of NAION) using an LSFG-Micro. We used the mean blur rate (MBR) of the vessel region (MV) and MBR of the tissue region (MT) as indicators of blood flow. We compared the MBR of the right and left eyes in both the normal rats and the rNAION group. In the normal rats, there were no significant differences in MV or MT between the right and left eyes. In the rNAION group, the MV and MT of the affected eyes were significantly lower than those of the unaffected eyes at all time points. There were significant differences between the left/right MV and MT ratios seen before the induction of NAION and those observed at 1, 3, 7, 14, and 28 days after the induction of NAION. However, there were no significant differences in these parameters among any of post-NAION induction time points. Our results indicated that the ONH blood flow of the rNAION rats fell in the acute and chronic phases.

Analysis of the Retention and Affiliation Factors Affecting the Active and Reserve Naval Nurse Corps

DTIC Science & Technology

2007-03-01

affiliation rates with the reserves among those who left active duty services. The thesis is composed of two parts: (1) an organizational analysis of...characteristics of those who are retained in the active Naval Nurse Corps and those who affiliate with the reserve Naval Nurse Corps using ...active Naval Nurse Corps and affiliation rates with the reserves among those who left active duty services. The thesis is composed of two parts: (1

Double-chambered left ventricle in a cat.

PubMed

Smith, Paul J; Tarazi, Marwan N; Ho, Siew Yen

2014-06-01

Double-chambered left ventricle is a rare congenital disorder in which the left ventricular cavity is subdivided into two cavities by an anomalous septum or muscle band. We describe a case of double-chambered left ventricle, most likely caused by the presence of excessive left ventricular bands, in an asymptomatic cat. Copyright © 2014 Elsevier B.V. All rights reserved.

Physiological control of dual rotary pumps as a biventricular assist device using a master/slave approach.

PubMed

Stevens, Michael C; Wilson, Stephen; Bradley, Andrew; Fraser, John; Timms, Daniel

2014-09-01

Dual rotary left ventricular assist devices (LVADs) can provide biventricular mechanical support during heart failure. Coordination of left and right pump speeds is critical not only to avoid ventricular suction and to match cardiac output with demand, but also to ensure balanced systemic and pulmonary circulatory volumes. Physiological control systems for dual LVADs must meet these objectives across a variety of clinical scenarios by automatically adjusting left and right pump speeds to avoid catastrophic physiological consequences. In this study we evaluate a novel master/slave physiological control system for dual LVADs. The master controller is a Starling-like controller, which sets flow rate as a function of end-diastolic ventricular pressure (EDP). The slave controller then maintains a linear relationship between right and left EDPs. Both left/right and right/left master/slave combinations were evaluated by subjecting them to four clinical scenarios (rest, postural change, Valsalva maneuver, and exercise) simulated in a mock circulation loop. The controller's performance was compared to constant-rotational-speed control and two other dual LVAD control systems: dual constant inlet pressure and dual Frank-Starling control. The results showed that the master/slave physiological control system produced fewer suction events than constant-speed control (6 vs. 62 over a 7-min period). Left/right master/slave control had lower risk of pulmonary congestion than the other control systems, as indicated by lower maximum EDPs (15.1 vs. 25.2-28.4 mm Hg). During exercise, master/slave control increased total flow from 5.2 to 10.1 L/min, primarily due to an increase of left and right pump speed. Use of the left pump as the master resulted in fewer suction events and lower EDPs than when the right pump was master. Based on these results, master/slave control using the left pump as the master automatically adjusts pump speed to avoid suction and increases pump flow during exercise without causing pulmonary venous congestion. Copyright © 2014 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Ventricular flow dynamics with varying LVAD inflow cannula lengths: In-silico evaluation in a multiscale model.

PubMed

Liao, Sam; Neidlin, Michael; Li, Zhiyong; Simpson, Benjamin; Gregory, Shaun D

2018-04-27

Left ventricular assist devices are associated with thromboembolic events, which are potentially caused by altered intraventricular flow. Due to patient variability, differences in apical wall thickness affects cannula insertion lengths, potentially promoting unfavourable intraventricular flow patterns which are thought to be correlated to the risk of thrombosis. This study aimed to present a 3D multiscale computational fluid dynamic model of the left ventricle (LV) developed using a commercial software, Ansys, and evaluate the risk of thrombosis with varying inflow cannula insertion lengths in a severely dilated LV. Based on a HeartWare HVAD inflow cannula, insertion lengths of 5, 19, 24 and 50 mm represented cases of apical hypertrophy, typical ranges of apical thicknesses and an experimental length, respectively. The risk of thrombosis was evaluated based on blood washout, residence time, instantaneous blood stagnation and a pulsatility index. By introducing fresh blood to displace pre-existing blood in the LV, after 5 cardiac cycles, 46.7%, 45.7%, 45.1% and 41.8% of pre-existing blood remained for insertion lengths of 5, 19, 24 and 50 mm, respectively. Compared to the 50 mm insertion, blood residence time was at least 9%, 7% and 6% higher with the 5, 19 and 24 mm insertion lengths, respectively. No instantaneous stagnation at the apex was observed directly after the E-wave. Pulsatility indices adjacent to the cannula increased with shorter insertion lengths. For the specific scenario studied, a longer insertion length, relative to LV size, may be advantageous to minimise thrombosis by increasing LV washout and reducing blood residence time. Copyright © 2018 Elsevier Ltd. All rights reserved.

Early in vivo experience with the pediatric continuous-flow total artificial heart.

PubMed

Karimov, Jamshid H; Horvath, David J; Byram, Nicole; Sunagawa, Gengo; Kuban, Barry D; Gao, Shengqiang; Dessoffy, Raymond; Fukamachi, Kiyotaka

2018-03-30

Heart transplantation in infants and children is an accepted therapy for end-stage heart failure, but donor organ availability is low and always uncertain. Mechanical circulatory support is another standard option, but there is a lack of intracorporeal devices due to size and functional range. The purpose of this study was to evaluate the in vivo performance of our initial prototype of a pediatric continuous-flow total artificial heart (P-CFTAH), comprising a dual pump with one motor and one rotating assembly, supported by a hydrodynamic bearing. In acute studies, the P-CFTAH was implanted in 4 lambs (average weight: 28.7 ± 2.3 kg) via a median sternotomy under cardiopulmonary bypass. Pulmonary and systemic pump performance parameters were recorded. The experiments showed good anatomical fit and easy implantation, with an average aortic cross-clamp time of 98 ± 18 minutes. Baseline hemodynamics were stable in all 4 animals (pump speed: 3.4 ± 0.2 krpm; pump flow: 2.1 ± 0.9 liters/min; power: 3.0 ± 0.8 W; arterial pressure: 68 ± 10 mm Hg; left and right atrial pressures: 6 ± 1 mm Hg, for both). Any differences between left and right atrial pressures were maintained within the intended limit of ±5 mm Hg over a wide range of ratios of systemic-to-pulmonary vascular resistance (0.7 to 12), with and without pump-speed modulation. Pump-speed modulation was successfully performed to create arterial pulsation. This initial P-CFTAH prototype met the proposed requirements for self-regulation, performance, and pulse modulation. Copyright © 2018 International Society for the Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.

[Clinical evaluation of regurgitant blood flow by rapid cine magnetic resonance imaging in patients with valvular heart disease].

PubMed

Onishi, S; Fukui, S; Atsumi, C; Morita, R; Fujii, K; Kusuoka, H; Kitabatake, A; Kamada, T; Takizawa, O

1989-06-01

The clinical usefulness of magnetic resonance imaging (MRI) for evaluating regurgitant blood flow in patients with valvular heart disease was studied. The study subjects comprised three healthy volunteers and nine patients with valvular heart disease (aortic regurgitation 3, mitral regurgitation 2, tricuspid regurgitation 2, and pulmonary regurgitation 2). Five were men and seven were women, ranging in age from 31 to 85 years. Valvular heart disease was diagnosed by two-dimensional Doppler echocardiography. MRI was performed using a 1.5 tesla super-conductive magnet system (MAGNETOM, Siemens AG). A rapid MRI technique (fast low-angle shot [FLASH], flip angle = 30 degrees, TR = 65-90 msec, TE = 10-38 msec) was used to generate 11 frames throughout one cardiac cycle in the transaxial, coronal and oblique planes. These sequential frames were displayed in cine mode on a CRT. 1. Intracavitary blood was imaged as a high signal intensity on gradient echo images, while surrounding cardiac structures had somewhat lower signal intensities. 2. In healthy volunteers, systolic ejection blood flow from the left ventricle was observed on coronal images in the cine mode display. The influx of atrial blood into the left and right ventricles was also clearly observed on transaxial cine images. 3. Aortic regurgitant flow was observed as areas of no signal intensity within the left ventricular cavity during diastole on coronal images. 4. Mitral and tricuspid regurgitations were observed within the left and right atria, respectively, as areas of no signal intensity on transaxial images. The extent of regurgitant flow was determined in the vertical long-axis plane, equivalent to the right anterior oblique projection. 5. The vertical oblique scan was suitable for detecting pulmonary regurgitant flow. These results indicate that the rapid cine MRI technique is a useful tool for noninvasively determining regurgitant blood flow in patients with various valvular heart diseases.

Vertebrate Left-Right Asymmetry: What Can Nodal Cascade Gene Expression Patterns Tell Us?

PubMed

Schweickert, Axel; Ott, Tim; Kurz, Sabrina; Tingler, Melanie; Maerker, Markus; Fuhl, Franziska; Blum, Martin

2017-12-29

Laterality of inner organs is a wide-spread characteristic of vertebrates and beyond. It is ultimately controlled by the left-asymmetric activation of the Nodal signaling cascade in the lateral plate mesoderm of the neurula stage embryo, which results from a cilia-driven leftward flow of extracellular fluids at the left-right organizer. This scenario is widely accepted for laterality determination in wildtype specimens. Deviations from this norm come in different flavors. At the level of organ morphogenesis, laterality may be inverted (situs inversus) or non-concordant with respect to the main body axis (situs ambiguus or heterotaxia). At the level of Nodal cascade gene activation, expression may be inverted, bilaterally induced, or absent. In a given genetic situation, patterns may be randomized or predominantly lacking laterality (absence or bilateral activation). We propose that the distributions of patterns observed may be indicative of the underlying molecular defects, with randomizations being primarily caused by defects in the flow-generating ciliary set-up, and symmetrical patterns being the result of impaired flow sensing, on the left, the right, or both sides. This prediction, the reasoning of which is detailed in this review, pinpoints functions of genes whose role in laterality determination have remained obscure.

Biventricular support with the Jarvik 2000 axial flow pump: a feasibility study.

PubMed

Radovancevic, Branislav; Gregoric, Igor D; Tamez, Daniel; Vrtovec, Bojan; Tuzun, Egemen; Chee, Hyun Keun; Moore, Sheila; Jarvik, Robert K; Frazier, O H

2003-01-01

Patients with congestive heart failure who are supported with a left ventricular assist device (LVAD) may experience right ventricular dysfunction or failure that requires support with a right ventricular assist device (RVAD). To determine the feasibility of using a clinically available axial flow ventricular assist device as an RVAD, we implanted Jarvik 2000 pumps in the left ventricle and right atrium of two Corriente crossbred calves (approximately 100 kg each) by way of a left thoracotomy and then analyzed the hemodynamic effects in the mechanically fibrillated heart at various LVAD and RVAD speeds. Right atrial implantation of the device required no modification of either the device or the surgical technique used for left ventricular implantation. Satisfactory biventricular support was achieved during fibrillation as evidenced by an increase in mean aortic pressure from 34 mm Hg with the pumps off to 78 mm Hg with the pumps generating a flow rate of 4.8 L/min. These results indicate that the Jarvik 2000 pump, which can provide chronic circulatory support and can be powered by external batteries, is a feasible option for right ventricular support after LVAD implantation and is capable of completely supporting the circulation in patients with global heart failure.

Investigation of mammary blood flow changes by transrectal colour Doppler sonography in an Escherichia coli mastitis model.

PubMed

Potapow, André; Sauter-Louis, Carola; Schmauder, Sandra; Friker, Jutta; Nautrup, Cordula Poulsen; Mehne, Daniel; Petzl, Wolfram; Zerbe, Holm

2010-05-01

The objectives of this preliminary investigation were to evaluate the feasibility of transrectal colour Doppler sonography (TCDS) for determining blood flow of the pudendoepigastric trunk in cows with experimentally induced Escherichia coli Mastitis. Five primiparous Holstein dairy cows, 4-6 months after calving, were examined in two trials. All monitored udder quarters were initially clinically healthy, somatic cell count (SCC) was <50 000 cells/ml and bacteriologically negative. The blood flow of the left and the right pudendoepigastric trunk was described by the blood flow volume (BFV). In the methodological part of the study, the intra-observer precision of the method was evaluated. The coefficients of variation of the BFV were 7.1% for the left and 9.4% for the right pudendoepigastric trunk. The intraclass correlation coefficients of the BFV were 0.99 (P<0.001) for the left and 0.75 (P=0.004) for the right vessel. BFV did not differ significantly between the left and the right side nor between pre- and post-milking nor between oestrus and dioestrus. In the experimental part of the study, significant differences of increasing BFV between 0 and 12 h p.i. (post infectionem) (P=0.043) and decreasing BFV between 12 and 24 h p.i. (P=0.043) were discovered for the pudendoepigastric trunk of the infected right side. In the left-right (control-infection) comparison a significant increase of the right BFV was observed at 12 h p.i. (P=0.043). The difference of an increasing SCC correlated positively with the difference of an increasing BFV between 0 and 12 h p.i. (Spearman's rho=1.00; P=0.043) for the right infected side. It was shown that TCDS is a reproducible technique for investigating pathological mammary blood flow changes at an early stage of acute mastitis.

Overcoming spatio-temporal limitations using dynamically scaled in vitro PC-MRI - A flow field comparison to true-scale computer simulations of idealized, stented and patient-specific left main bifurcations.

PubMed

Beier, Susann; Ormiston, John; Webster, Mark; Cater, John; Norris, Stuart; Medrano-Gracia, Pau; Young, Alistair; Gilbert, Kathleen; Cowan, Brett

2016-08-01

The majority of patients with angina or heart failure have coronary artery disease. Left main bifurcations are particularly susceptible to pathological narrowing. Flow is a major factor of atheroma development, but limitations in imaging technology such as spatio-temporal resolution, signal-to-noise ratio (SNRv), and imaging artefacts prevent in vivo investigations. Computational fluid dynamics (CFD) modelling is a common numerical approach to study flow, but it requires a cautious and rigorous application for meaningful results. Left main bifurcation angles of 40°, 80° and 110° were found to represent the spread of an atlas based 100 computed tomography angiograms. Three left mains with these bifurcation angles were reconstructed with 1) idealized, 2) stented, and 3) patient-specific geometry. These were then approximately 7× scaled-up and 3D printing as large phantoms. Their flow was reproduced using a blood-analogous, dynamically scaled steady flow circuit, enabling in vitro phase-contrast magnetic resonance (PC-MRI) measurements. After threshold segmentation the image data was registered to true-scale CFD of the same coronary geometry using a coherent point drift algorithm, yielding a small covariance error (σ 2 <;5.8×10 -4 ). Natural-neighbour interpolation of the CFD data onto the PC-MRI grid enabled direct flow field comparison, showing very good agreement in magnitude (error 2-12%) and directional changes (r 2 0.87-0.91), and stent induced flow alternations were measureable for the first time. PC-MRI over-estimated velocities close to the wall, possibly due to partial voluming. Bifurcation shape determined the development of slow flow regions, which created lower SNRv regions and increased discrepancies. These can likely be minimised in future by testing different similarity parameters to reduce acquisition error and improve correlation further. It was demonstrated that in vitro large phantom acquisition correlates to true-scale coronary flow simulations when dynamically scaled, and thus can overcome current PC-MRI's spatio-temporal limitations. This novel method enables experimental assessment of stent induced flow alternations, and in future may elevate CFD coronary flow simulations by providing sophisticated boundary conditions, and enable investigations of stenosis phantoms.

Morphogenesis of the node and notochord: the cellular basis for the establishment and maintenance of left-right asymmetry in the mouse.

PubMed

Lee, Jeffrey D; Anderson, Kathryn V

2008-12-01

Establishment of left-right asymmetry in the mouse embryo depends on leftward laminar fluid flow in the node, which initiates a signaling cascade that is confined to the left side of the embryo. Leftward fluid flow depends on two cellular processes: motility of the cilia that generate the flow and morphogenesis of the node, the structure where the cilia reside. Here, we provide an overview of the current understanding and unresolved questions about the regulation of ciliary motility and node structure. Analysis of mouse mutants has shown that the motile cilia must have a specific structure and length, and that they must point posteriorly to generate the necessary leftward fluid flow. However, the precise structure of the motile cilia is not clear and the mechanisms that position cilia on node cells have not been defined. The mouse node is a teardrop-shaped pit at the distal tip of the early embryo, but the morphogenetic events that create the mature node from cells derived from the primitive streak are only beginning to be characterized. Recent live imaging experiments support earlier scanning electron microscopy (SEM) studies and show that node assembly is a multi-step process in which clusters of node precursors appear on the embryo surface as overlying endoderm cells are removed. We present additional SEM and confocal microscopy studies that help define the transition stages during node morphogenesis. After the initiation of left-sided signaling, the notochordal plate, which is contiguous with the node, generates a barrier at the embryonic midline that restricts the cascade of gene expression to the left side of the embryo. The field is now poised to dissect the genetic and cellular mechanisms that create and organize the specialized cells of the node and midline that are essential for left-right asymmetry. (c) 2008 Wiley-Liss, Inc.

The impact of tissue Doppler index E/e' ratio on instantaneous wave-free ratio.

PubMed

Arashi, Hiroyuki; Yamaguchi, Junichi; Ri, Tonre; Otsuki, Hisao; Nakao, Masashi; Kamishima, Kazuho; Jujo, Kentaro; Minami, Yuichiro; Ogawa, Hiroshi; Hagiwara, Nobuhisa

2018-03-01

The instantaneous wave-free ratio (iFR) is a vasodilator-free, invasive pressure wire index of the functional severity of coronary stenosis and is calculated under resting conditions. In a recent study, iFR was found to be more closely linked to coronary flow reserve (CFR) than fractional flow reserve (FFR). E/e' is a surrogate marker of left ventricular (LV) filling pressure and LV diastolic dysfunction. Coronary resting flow was found to be increased in patients with elevated E/e', and higher coronary resting flow was associated with lower CFR. Higher baseline coronary flow induces a greater loss of translesional pressure and may affect iFR. However, no reports have examined the impact of E/e' on iFR. The purpose of this study was to assess the relationship between iFR and E/e' compared with FFR. We retrospectively examined 103 consecutive patients (142 with stenosis) whose iFR, FFR, and E/e' were measured simultaneously. The mean age, LV mass index, and systolic blood pressure of patients with elevated E/e' were higher than those of patients with normal E/e'. Although no significant differences were observed in mean FFR values and % diameter stenosis, the mean iFR value in patients with elevated E/e' was significantly lower than that in patients with normal E/e'. The iFR was negatively correlated with E/e', while there was no correlation between FFR and E/e'. Multivariate analysis showed that E/e' and % diameter stenosis were independent determinants of iFR. E/e' ratio affects iFR values. Our results suggest that FFR mainly reflects the functional severity of the epicardial stenosis whereas iFR could potentially be influenced by not only epicardial stenosis but also other factors related to LV filling pressure or LV diastolic dysfunction. Further research is needed to understand the underlying mechanisms that influence the evaluation of iFR in patients with elevated E/e'. Copyright © 2017 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.

Regional myocardial flow and capillary permeability-surface area products are nearly proportional.

PubMed

Caldwell, J H; Martin, G V; Raymond, G M; Bassingthwaighte, J B

1994-08-01

Analyses of data on the transcapillary exchange and cellular uptake in the normal heart have generally been based on the assumption that local membrane conductances and volumes of distribution are everywhere the same. The question is whether such an assumption is justified in view of the marked (sixfold) heterogeneity of local blood flows per gram tissue. The method was to estimate both flow and capillary membrane permeability-surface area products (PS) locally in the heart. For each of five dogs running on a sloped treadmill, the deposition of tracer microspheres and of [131I]iodophenylpentadecanoic acid (IPPA), after left atrial injection, was determined in 256 pieces of left ventricular myocardium by killing the animals at approximately 100 s after radiotracer injection. A hydraulic occluder stopped the flow to a portion of the myocardium supplied by the left circumflex coronary artery 30 s before tracer injection. Regional flows ranged from 0.1 to 7.0 ml.g-1.min-1. IPPA extractions ranged from 20 to 49%. Using the known flows, we assumed the applicability of an axially distributed blood-tissue exchange model to estimate the PS for the capillary (PSc) and the parenchymal cell. It was impossible to explain the data if the PSc values for membrane transport were uniform throughout the organ. Rather, the only reasonable descriptors of the data required that local PSc values increase with local flow, almost in proportion. Current methods of analysis using data based on deposition methods need to be revised to take into account the near proportionality of PS to flow for at least some substrates.

Innominate Vein Stenosis in Association with Ipsilateral Hyperdynamic Brachiobasilic Fistula Causing Ipsilateral Limb and Hemifacial Swelling.

PubMed

Narendra, J B; Sreenivas, J; Karthikeyan, V S; Nagaraja, N H

2017-01-01

A 34-year-old hypertensive woman with a hyperdynamic, left brachiobasilic dialysis fistula presented with a long history of throbbing in her head and swelling of the left side of the face. Tight stenosis of left brachiocephalic vein was found to be causing retrograde flow into the left jugular vein which normalized after dilatation and stenting with resolution of all the symptoms and patient is asymptomatic for 1 year.

Use of Computational Modeling to Inform tDCS Electrode Montages for the Promotion of Language Recovery in Post-stroke Aphasia.

PubMed

Galletta, Elizabeth E; Cancelli, Andrea; Cottone, Carlo; Simonelli, Ilaria; Tecchio, Franca; Bikson, Marom; Marangolo, Paola

2015-01-01

Although pilot trials of transcranial direct current stimulation (tDCS) in aphasia are encouraging, protocol optimization is needed. Notably, it has not yet been clarified which of the varied electrode montages investigated is the most effective in enhancing language recovery. To consider and contrast the predicted brain current flow patterns (electric field distribution) produced by varied 1×1 tDCS (1 anode, 1 cathode, 5 × 7 cm pad electrodes) montages used in aphasia clinical trials. A finite element model of the head of a single left frontal stroke patient was developed in order to study the pattern of the cortical EF magnitude and inward/outward radial EF under five different electrode montages: Anodal-tDCS (A-tDCS) over the left Wernicke's area (Montage A) and over the left Broca's area (Montage B); Cathodal tDCS (C-tDCS) over the right homologue of Wernicke's area (Montage C), and of Broca's area (Montage D), where for all montages A-D the "return" electrode was placed over the supraorbital contralateral forehead; bilateral stimulation with A-tDCS over the left Broca's and CtDCS over the right Broca's homologue (Montage E). In all cases, the "return" electrode over the contralesional supraorbital forehead was not inert and influenced the current path through the entire brain. Montage B, although similar to montage D in focusing the current in the perilesional area, exerted the greatest effect over the left perilesional cortex, which was even stronger in montage E. The position and influence of both electrodes must be considered in the design and interpretation of tDCS clinical trials for aphasia. Copyright © 2015 Elsevier Inc. All rights reserved.

Urinary type IV collagen is related to left ventricular diastolic function and brain natriuretic peptide in hypertensive patients with prediabetes.

PubMed

Iida, Masato; Yamamoto, Mitsuru; Ishiguro, Yuko S; Yamazaki, Masatoshi; Ueda, Norihiro; Honjo, Haruo; Kamiya, Kaichirou

2014-01-01

Urinary type IV collagen is an early biomarker of diabetic nephropathy. Concomitant prediabetes (the early stage of diabetes) was associated with left ventricular (LV) diastolic dysfunction and increased brain natriuretic peptide (BNP) in hypertensive patients. We hypothesized that urinary type IV collagen may be related to these cardiac dysfunctions. We studied hypertensive patients with early prediabetes (HbA1c <5.7% and fasting glucose >110, n=18), those with prediabetes (HbA1c 5.7-6.4, n=98), and those with diabetes (HbA1c>6.5 or on diabetes medications, n=92). The participants underwent echocardiography to assess left atrial volume/body surface area (BSA) and the ratio of early mitral flow velocity to mitral annular velocity (E/e'). Left ventricular diastolic dysfunction (LVDD) was defined if patients had E/e'≥15, or E/e'=9-14 accompanied by left atrial volume/BSA≥32ml/mm(2). Urinary samples were collected for type IV collagen and albumin, and blood samples were taken for BNP and HbA1c. Urinary type IV collagen and albumin increased in parallel with the deterioration of glycemic status. In hypertensive patients with prediabetes, subjects with LVDD had higher levels of BNP and urinary type IV collagen than those without LVDD. In contrast, in hypertensive patients with diabetes, subjects with LVDD had higher urinary albumin and BNP than those without LVDD. Urinary type IV collagen correlated positively with BNP in hypertensive patients with prediabetes, whereas it correlated with HbA1c in those with diabetes. In hypertensive patients with prediabetes, urinary type IV collagen was associated with LV diastolic dysfunction and BNP. Copyright © 2014 Elsevier Inc. All rights reserved.

Irritable bowel syndrome in female patients is associated with alterations in structural brain networks.

PubMed

Labus, Jennifer S; Dinov, Ivo D; Jiang, Zhiguo; Ashe-McNalley, Cody; Zamanyan, Alen; Shi, Yonggang; Hong, Jui-Yang; Gupta, Arpana; Tillisch, Kirsten; Ebrat, Bahar; Hobel, Sam; Gutman, Boris A; Joshi, Shantanu; Thompson, Paul M; Toga, Arthur W; Mayer, Emeran A

2014-01-01

Alterations in gray matter (GM) density/volume and cortical thickness (CT) have been demonstrated in small and heterogeneous samples of subjects with differing chronic pain syndromes, including irritable bowel syndrome (IBS). Aggregating across 7 structural neuroimaging studies conducted at University of California, Los Angeles, Los Angeles, CA, USA, between August 2006 and April 2011, we examined group differences in regional GM volume in 201 predominantly premenopausal female subjects (82 IBS, mean age: 32±10 SD, 119 healthy controls [HCs], 30±10 SD). Applying graph theoretical methods and controlling for total brain volume, global and regional properties of large-scale structural brain networks were compared between the group with IBS and the HC group. Relative to HCs, the IBS group had lower volumes in the bilateral superior frontal gyrus, bilateral insula, bilateral amygdala, bilateral hippocampus, bilateral middle orbital frontal gyrus, left cingulate, left gyrus rectus, brainstem, and left putamen. Higher volume was found in the left postcentral gyrus. Group differences were no longer significant for most regions when controlling for the Early Trauma Inventory global score, with the exception of the right amygdala and the left postcentral gyrus. No group differences were found for measures of global and local network organization. Compared to HCs, in patients with IBS, the right cingulate gyrus and right thalamus were identified as being significantly more critical for information flow. Regions involved in endogenous pain modulation and central sensory amplification were identified as network hubs in IBS. Overall, evidence for central alterations in patients with IBS was found in the form of regional GM volume differences and altered global and regional properties of brain volumetric networks. Copyright © 2013 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

The effects of vasoactive peptide urocortin 2 on hemodynamics in spontaneous hypertensive rat and the role of L-type calcium channel and CRFR2.

PubMed

Liu, Chunna; Liu, Xinyu; Yang, Jing; Duan, Yan; Yao, Hongyue; Li, Fenghua; Zhang, Xia

2015-04-01

Urocortin (UCN) is a newly identified vascular-active peptide that has been shown to reverse cardiovascular remodeling and improve left ventricular (LV) function. The effects and mechanism of urocortin 2 (UCN2) in vivo on the electrical remodeling of left ventricle and the hemodynamics of hypertensive objectives have not been investigated. UCN2 (1 μg/kg/d, 3.5 μg/kg/d or 7 μg/kg/d) was intravenously injected for 2 weeks and its effects on hemodynamics in spontaneously hypertensive rats (SHRs) observed. The whole-cell patch clamp technique was used to explore the effects of UCN2 on the electrical remodeling of left ventricular cardiomyocytes. The flow cytometry method was used to determine the content of fluorescence calcium in myocardium. UCN2 improved the systolic and diastolic function of SHRs as demonstrated by decreased left ventricular systolic pressure (LVSP), left ventricular end diastolic pressure (LVEDP), increased +dp/dtmax and -dp/dtmax and decreased cAMP level. UCN2 inhibited the opening of L-type calcium channel and decreased the calcium channel current of cardiomyocytes. In addition, UCN2 also decreased the contents of fluorescence calcium in SHR myocardium. However, astressin2-B (AST-2B), the antagonist of corticotropin-releasing factor receptor 2 (CRFR2), could reverse the inhibitory effects of UCN2 on calcium channel. UCN2 can modulate electrical remodeling of the myocardium and hemodynamics in an experimental model of SHR via inhibition of L-type calcium channel and CRFR2 in cardiomyocytes. Copyright © 2014 Institute of Pharmacology, Polish Academy of Sciences. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

Hyperperfusion syndrome after trapping with high-flow bypass for a giant paraclinoid internal carotid artery aneurysm.

PubMed

Mohri, Masanao; Ichinose, Toshiya; Uchiyama, Naoyuki; Misaki, Kouichi; Nambu, Iku; Takabatake, Yasushi; Nakada, Mitsutoshi

2018-04-21

Hyperperfusion syndrome associated with aneurysm surgery is rare. The occurrence of the syndrome after trapping with high-flow bypass has not been described previously. Herein, we present a case of the syndrome occurring after trapping with high-flow bypass of an unruptured giant paraclinoid internal carotid artery (ICA) aneurysm. The patient was a 68-year-old woman with progressive loss of vision in her left eye. After a diagnosis of a left giant ICA aneurysm, she underwent successful trapping with high-flow bypass. No new neurological deficits were observed after surgery. Computed tomography (CT) on the same day and magnetic resonance imaging (MRI) on the next day revealed no hemorrhage or infarction. The patient had a headache and transit motor aphasia on postoperative day (POD) 8. Arterial spin-labeling magnetic resonance perfusion image on the same day and single photon emission CT scan on POD 10 demonstrated hyperperfusion in the left cerebral cortex. The symptoms gradually improved over a week and she had no new neurological deficits when discharged from hospital. This report suggests that, although rare, hyperperfusion syndrome after trapping with high-flow bypass should be considered in giant aneurysmal patients if they present with headache and neurological deficits in a delayed period. Copyright © 2018. Published by Elsevier Inc.

Local-Rapid Evaluation of Atmospheric Conditions (L-REAC (trademark)) System, Design and Development. Volume 3. (Operational L-REAC (trademark))

DTIC Science & Technology

2011-09-01

tunnel results show the airflow pattern around a single building. Streamline flow is from left to right. The “canyon flow” is not shown. (Snyder...Agency (EPA)/National Oceanic and Atmospheric Administration (NOAA) wind tunnel results by sampling atmospheric data at strategic locations around a...NOAA wind tunnel results show the airflow pattern around a single building. Streamline flow is from left to right. The “canyon flow” is not shown

Can nerve regeneration on an artificial nerve conduit be enhanced by ethanol-induced cervical sympathetic ganglion block?

PubMed Central

Sunada, Katsuhisa; Shigeno, Keiji; Nakada, Akira; Honda, Michitaka; Nakamura, Tatsuo

2017-01-01

This study aimed to determine whether nerve regeneration by means of an artificial nerve conduit is promoted by ethanol-induced cervical sympathetic ganglion block (CSGB) in a canine model. This study involved two experiments—in part I, the authors examined the effect of CSGB by ethanol injection on long-term blood flow to the orofacial region; part II involved evaluation of the effect of CSGB by ethanol injection on inferior alveolar nerve (IAN) repair using polyglycolic acid-collagen tubes. In part I, seven Beagles were administered left CSGB by injection of 99.5% ethanol under direct visualization by means of thoracotomy, and changes in oral mucosal blood flow in the mental region and nasal skin temperature were evaluated. The increase in blood flow on the left side lasted for 7 weeks, while the increase in average skin temperature lasted 10 weeks on the left side and 3 weeks on the right. In part II, fourteen Beagles were each implanted with a polyglycolic acid-collagen tube across a 10-mm gap in the left IAN. A week after surgery, seven of these dogs were administered CSGB by injection of ethanol. Electrophysiological findings at 3 months after surgery revealed significantly higher sensory nerve conduction velocity and recovery index (ratio of left and right IAN peak amplitudes) after nerve regeneration in the reconstruction+CSGB group than in the reconstruction-only group. Myelinated axons in the reconstruction+CSGB group were greater in diameter than those in the reconstruction-only group. Administration of CSGB with ethanol resulted in improved nerve regeneration in some IAN defects. However, CSGB has several physiological effects, one of which could possibly be the long-term increase in adjacent blood flow. PMID:29220373

iss012e15918

NASA Image and Video Library

2006-01-24

ISS012-E-15918 (24 Jan. 2006) --- Belle Isle and a portion of Newfoundland, Canada are featured in this image photographed by an Expedition 12 crew member on the International Space Station. Belle Isle (center) is surrounded by sea ice in this recent winter view. Belle Isle lies in the strait between the Island of Newfoundland and Labrador (the mainland portion of Canada’s province of Newfoundland). Small islands along the coast of Labrador appear in the top left corner. In this key location Belle Isle lies on the shortest shipping lanes between the Great Lakes and Europe, and also on the main north-south shipping route to Hudson Bay and the Northwest Territories. Snow and ice in this recent winter view obliterate the dozens of glacier-scoured lakes that dot the surface of the island. The single community of Belle Isle Landing on the southeast tip is equally hard to see. Ice patterns also show that the island lies at the meeting point of two sea currents. The Labrador Current flows from the northwest (top left), and a smaller current, driven by dominant westerly winds, flows from the southwest (lower left) out of the narrow Belle Isle Strait (out of frame lower left). Flow lines in sea ice indicate the sense of movement of the ice. Ice floes embedded in the Labrador Current appear in the upper part of the image as a relatively open pattern. Sea ice with a denser pattern enters from the lower left corner, banking against the west side of Belle Isle. Tendrils flow around capes at either end of the island, with an ice-free “shadow” on the opposite, downstream side. Eddies (center) in the ice patterns show where the currents interact, north and west of the island.

Comparison of pulsatile with nonpulsatile mechanical support in a porcine model of profound cardiogenic shock.

PubMed

Drakos, Stavros G; Charitos, Christos E; Ntalianis, Argirios; Terrovitis, John V; Siafakas, Kostas X; Dolou, Paraskevi; Pierrakos, Charalampos; Charitos, Efstratios; Karelas, John; Nanas, John N

2005-01-01

The aim of this study was to examine whether pulsatility by intraaortic balloon counterpulsation (IABP) is an important adjunct to the treatment of profound cardiogenic shock (CS) with a widely used, nonpulsatile centrifugal pump (CP). In each of 18 anesthetized, open chest pigs, the outflow cannula of the CP was inserted in the aortic arch through the right external carotid artery, and the inflow cannula of the CP was placed in the left atrium. A 40 cc IABP was subsequently placed in the descending aorta through the left external carotid artery. CS was induced by occlusion of coronary arteries and the infusion of propranolol and crystalloid fluid. Mean aortic pressure, pulse pressure, aortic end diastolic pressure, left ventricular end diastolic pressure, right atrial pressure, and heart rate were monitored. Cardiac output and left anterior descending artery flow were measured with a transit time ultrasound flowmeter. During profound CS, life sustaining hemodynamics were maintained only with the support of the assist devices. Hemodynamic support with the CP was associated with a nearly nonpulsatile flow and a pulse pressure of 7 +/- 4 mm Hg, which increased to 33 +/- 10 mm Hg (p = 0.000) after combining the CP with the IABP. Compared with the hemodynamic support offered by the CP alone, addition of the IABP increased mean aortic pressure from 40 +/- 15 to 50 +/- 16 mm Hg (p = 0.000), cardiac output from 810 +/- 194 to 1,200 +/- 234 ml/min (p = 0.003), and left anterior descending artery flow from 26 +/- 10 to 39 +/- 14 ml/min (p = 0.001). In profound CS, mechanical support provided by a continuous flow CP is enhanced by the added pulsatility of the IABP.

Real-time three-dimensional color Doppler echocardiography for characterizing the spatial velocity distribution and quantifying the peak flow rate in the left ventricular outflow tract

NASA Technical Reports Server (NTRS)

Tsujino, H.; Jones, M.; Shiota, T.; Qin, J. X.; Greenberg, N. L.; Cardon, L. A.; Morehead, A. J.; Zetts, A. D.; Travaglini, A.; Bauer, F.;

15. NBS TOP SIDE CONTROL ROOM. THE SUIT SYSTEMS CONSOLE ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

15. NBS TOP SIDE CONTROL ROOM. THE SUIT SYSTEMS CONSOLE IS USED TO CONTROL AIR FLOW AND WATER FLOW TO THE UNDERWATER SPACE SUIT DURING THE TEST. THE SUIT SYSTEMS ENGINEER MONITORS AIR FLOW ON THE PANEL TO THE LEFT, AND SUIT DATA ON THE COMPUTER MONITOR JUST SLIGHTLY TO HIS LEFT. WATER FLOW IS MONITORED ON THE PANEL JUST SLIGHTLY TO HIS RIGHT AND TEST VIDEO TO HIS FAR RIGHT. THE DECK CHIEF MONITORS THE DIVER'S DIVE TIMES ON THE COMPUTER IN THE UPPER RIGHT. THE DECK CHIEF LOGS THEM IN AS THEY ENTER THE WATER, AND LOGS THEM OUT AS THEY EXIT THE WATER. THE COMPUTER CALCULATES TOTAL DIVE TIME. - Marshall Space Flight Center, Neutral Buoyancy Simulator Facility, Rideout Road, Huntsville, Madison County, AL

Severe hydronephrosis secondary to uterine artery pseudoaneurysm in the early second trimester of pregnancy: A case report.

PubMed

Amano, Tsukuru; Tokoro, Shinsuke; Tsuji, Shunichiro; Inoue, Takashi; Kimura, Fuminori; Murakami, Takashi

2017-09-25

Uterine artery pseudoaneurysm (UAP) normally presents genital bleeding in the puerperal period, and severe hydronephrosis rarely presents during pregnancy. We report a rare case of severe ureteral obstruction accompanied by uterine artery pseudoaneurysm in the early second trimester of pregnancy, which was successfully treated by surgical intervention. A 42-year-old nulligravid woman who had undergone myomectomy 3 years earlier was referred to our hospital for acute left abdominal pain at the 17th week of gestation. Ultrasonography showed severe left hydronephrosis and a 6-cm mass in the parauterine space. Color Doppler ultrasonography revealed a spinning turbulent flow pattern inside the mass lesion. Contrast-enhanced computed tomography revealed the left uterine artery feeding blood flow to the mass and left ureteral obstruction by the mass. These results indicated left hydronephrosis secondary to left uterine artery pseudoaneurysm. To resolve the problem, laparotomy was performed. As uterine artery isolation was impossible, ligation of the left internal iliac artery and releasing of the ureteral obstruction were carried out. The hydronephrosis and abdominal pain promptly resolved after the surgery. Thereafter, fetal development proceeded normally in the remaining months of the pregnancy. A healthy baby was delivered through cesarean section at 36 weeks gestational age. At the cesarean section, the left lower uterine segment where the UAP had been present was not visible because of the firm adhesion in around it. Uterine artery pseudoaneurysm can cause hydronephrosis in the early second trimester of pregnancy. Ligation of the unilateral internal iliac artery is a safe and effective intervention to block the blood flow to the uterine artery pseudoaneurysm during pregnancy, when uterine artery ligation seems not possible. In the pregnancy after previous surgical procedures to the uterus, uterine artery pseudoaneurysm should be considered in the differential diagnosis of symptomatic hydronephrosis.

Benchtop quantification of gutter formation and compression of chimney stent grafts in relation to renal flow in chimney endovascular aneurysm repair and endovascular aneurysm sealing configurations.

PubMed

Boersen, Johannes T; Donselaar, Esme J; Groot Jebbink, Erik; Starreveld, Roeliene; Overeem, Simon P; Slump, Cornelis H; de Vries, Jean-Paul P M; Reijnen, Michel M P J

2017-11-01

The chimney technique has been successfully used to treat juxtarenal aortic aneurysms. The two main issues with this technique are gutter formation and chimney graft (CG) compression, which induce a risk for type Ia endoleaks and stent thrombosis, respectively. In this benchtop study, the geometry and renal artery flow of chimney endovascular aneurysm repair configurations were compared with chimney configurations with endovascular aneurysm sealing (ch-EVAS). Seven flow phantoms were constructed, including one control and six chimney endovascular aneurysm repairs (Endurant [Medtronic Inc, Minneapolis, Minn] and AFX [Endologix Inc, Irvine, Calif]) or ch-EVAS (Nellix, Endologix) configurations, combined with either balloon-expandable or self-expanding CGs with an intended higher positioning of the right CG in comparison to the left CG. Geometric analysis was based on measurements at three-dimensional computed tomography angiography and included gutter volume and CG compression, quantified by the ratio between maximal and minimal diameter (D-ratio). In addition, renal artery flow was studied in a physiologic flow model and compared with the control. The average gutter volume was 343.5 ± 142.0 mm 3 , with the lowest gutter volume in the EVAS-Viabahn (W. L. Gore & Associates, Flagstaff, Ariz) combination (102.6 mm 3 ) and the largest in the AFX-Advanta V12 (Atrium Medical Corporation, Hudson, NH) configuration (559.6 mm 3 ). The maximum D-ratio was larger in self-expanding CGs than in balloon-expandable CGs in all configurations (2.02 ± 0.34 vs 1.39 ± 0.13). The CG compression had minimal influence on renal volumetric flow (right, 390.7 ± 29.4 mL/min vs 455.1 mL/min; left, 423.9 ± 28.3 mL/min vs 410.0 mL/min in the control). This study showed that gutter volume was lowest in ch-EVAS in combination with a Viabahn CG. CG compression was lower in configurations with the Advanta V12 than with Viabahn. Renal flow is unrestricted by CG compression. Copyright © 2016 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

Effects of posture on blood flow diversion by hypoxic pulmonary vasoconstriction in dogs

NASA Technical Reports Server (NTRS)

Walther, S. M.; Domino, K. B.; Hlastala, M. P.

1998-01-01

We used differential excretion of sulphur hexafluoride from the left and right lung to measure blood flow diversion by hypoxic pulmonary vasoconstriction (HPV) in the prone and supine positions in dogs (n = 9). Gas exchange was assessed using the multiple inert gas elimination technique. Blood flow diversion from the hypoxic (3% oxygen) left lung was mean 70.7 (SD 11.2)% in the supine compared with 57.0 (12.1)% in the prone position (P < 0.02). The supine position was associated with increased perfusion to low VA/Q regions (P < 0.05). The increased flow diversion with hypoxia in the supine position was associated with more ventilation to high VA/Q regions (P < 0.05). We conclude that flow diversion by hypoxic pulmonary vasoconstriction is greater in the supine position. This effect could contribute to the variable response in gas exchange with positioning in patients with ARDS.

Treatment of aortic stenosis with aortic valve bypass (apicoaortic conduit) surgery: an assessment using computational modeling.

PubMed

Balaras, Elias; Cha, K S; Griffith, Bartley P; Gammie, James S

2009-03-01

Aortic valve bypass surgery treats aortic valve stenosis with a valve-containing conduit that connects the left ventricular apex to the descending thoracic aorta. After aortic valve bypass, blood is ejected from the left ventricle via both the native stenotic aortic valve and the conduit. We performed computational modeling to determine the effects of aortic valve bypass on aortic and cerebral blood flow, as well as the effect of conduit size on relative blood flow through the conduit and the native valve. The interaction of blood flow with the vascular boundary was modeled using a hybrid Eurelian-Lagrangian formulation, where an unstructured Galerkin finite element method was coupled with an immersed boundary approach. Our model predicted native (stenotic) valve to conduit flow ratios of 45:55, 52:48, and 60:40 for conduits with diameters of 20, 16, and 10 mm, respectively. Mean gradients across the native aortic valve were calculated to be 12.5, 13.8, and 17.6 mm Hg, respectively. Post-aortic valve bypass cerebral blood flow was unchanged from preoperative aortic valve stenosis configurations and was constant across all conduit sizes. In all cases modeled, cerebral blood flow was completely supplied by blood ejected across the native aortic valve. An aortic valve bypass conduit as small as 10 mm results in excellent relief of left ventricular outflow tract obstruction in critical aortic valve stenosis. The presence of an aortic valve bypass conduit has no effect on cerebral blood flow. All blood flow to the brain occurs via antegrade flow across the native stenotic valve; this configuration may decrease the long-term risk of cerebral thromboembolism.

Nonlinear Pressure-Flow Relationship Is Able to Detect Asymmetry of Brain Blood Circulation Associated with Midline Shift

PubMed Central

Lo, Men-Tzung; Peng, C.K.; Novak, Vera; Schmidt, Eric A.; Kumar, Ajay; Czosnyka, Marek

2009-01-01

Abstract Reliable and noninvasive assessment of cerebral blood flow regulation is a major challenge in acute care monitoring. This study assessed dynamics of flow regulation and its relationship to asymmetry of initial computed tomography (CT) scan using multimodal pressure flow (MMPF) analysis. Data of 27 patients (38 ± 15 years old) with traumatic brain injury (TBI) were analyzed. Patients were selected from bigger cohort according to criteria of having midline shift on initial CT scan and intact skull (no craniotomy or bone flap). The MMPF analysis was used to extract the oscillations in cerebral perfusion pressure (CPP) and blood flow velocity (BFV) signals at frequency of artificial ventilation, and to calculate the instantaneous phase difference between CPP and BFV oscillations. Mean CPP-BFV phase difference was used to quantify pressure and flow relationship. The TBI subjects had smaller mean BP-BFV phase shifts (left, 8.7 ± 9.6; right 10.2 ± 8.3 MCAs, mean ± SD) than values previously obtained in healthy subjects (left, 37.3 ± 7.6 degrees; right, 38.0 ± 8.9 degrees; p < 0.0001), suggesting impaired blood flow regulation after TBI. The difference in phase shift between CPP and BFV in the left and right side was strongly correlated to the midline shift (R = 0.78; p < 0.0001). These findings indicate that the MMPF method allows reliable assessment of alterations in pressure and flow relationship after TBI. Moreover, mean pressure-flow phase shift is sensitive to the displacement of midline of the brain, and may potentially serve as a marker of asymmetry of cerebral autoregulation. PMID:19196074

Hemodynamics of a functional centrifugal-flow total artificial heart with functional atrial contraction in goats.

PubMed

Shiga, Takuya; Shiraishi, Yasuyuki; Sano, Kyosuke; Taira, Yasunori; Tsuboko, Yusuke; Yamada, Akihiro; Miura, Hidekazu; Katahira, Shintaro; Akiyama, Masatoshi; Saiki, Yoshikatsu; Yambe, Tomoyuki

2016-03-01

Implantation of a total artificial heart (TAH) is one of the therapeutic options for the treatment of patients with end-stage biventricular heart failure. There is no report on the hemodynamics of the functional centrifugal-flow TAH with functional atrial contraction (fCFTAH). We evaluated the effects of pulsatile flow by atrial contraction in acute animal models. The goats received fCFTAH that we created from two centrifugal-flow ventricular assist devices. Some hemodynamic parameters maintained acceptable levels: heart rate 115.5 ± 26.3 bpm, aortic pressure 83.5 ± 10.1 mmHg, left atrial pressure 18.0 ± 5.9 mmHg, pulmonary pressure 28.5 ± 9.7 mmHg, right atrial pressure 13.6 ± 5.2 mmHg, pump flow 4.0 ± 1.1 L/min (left) 3.9 ± 1.1 L/min (right), and cardiac index 2.13 ± 0.14 L/min/m(2). fCFTAH with atrial contraction was able to maintain the TAH circulation by forming a pulsatile flow in acute animal experiments. Taking the left and right flow rate balance using the low internal pressure loss of the VAD pumps may be easier than by other pumps having considerable internal pressure loss. We showed that the remnant atrial contraction effected the flow rate change of the centrifugal pump, and the atrial contraction waves reflected the heart rate. These results indicate that remnant atria had the possibility to preserve autonomic function in fCFTAH. We may control fCFTAH by reflecting the autonomic function, which is estimated with the flow rate change of the centrifugal pump.

Magnetic Heat Pump Containing Flow Diverters

NASA Technical Reports Server (NTRS)

Howard, Frank S.

1995-01-01

Proposed magnetic heat pump contains flow diverters for suppression of undesired flows. If left unchecked, undesired flows mix substantial amounts of partially heated and partially cooled portions of working fluid, effectively causing leakage of heat from heated side to cooled side. By reducing leakage of heat, flow diverters increase energy efficiency of magnetic heat pump, potentially offering efficiency greater than compressor-driven refrigerator.

Myocardial Blood Volume Is Associated with Myocardial Oxygen Consumption: An Experimental Study with CMR in a Canine Model

PubMed Central

McCommis, Kyle S.; Zhang, Haosen; Goldstein, Thomas A.; Misselwitz, Bernd; Abendschein, Dana R.; Gropler, Robert J.; Zheng, Jie

2009-01-01

OBJECTIVES To evaluate the feasibility of cardiovascular MR (CMR) to determine regional myocardial perfusion and O2 metabolism, and assess the role of myocardial blood volume (MBV) on oxygen supply. BACKGROUND Coronary artery disease presents as an imbalance of myocardial oxygen supply and demand. We have developed relevant CMR methods to determine the relationship of myocardial blood flow (MBF) and MBV to oxygen consumption (MVO2) during pharmacologic hyperemia. METHODS Twenty-one mongrel dogs were studied with varying stenosis severities imposed on the proximal left anterior descending (LAD) coronary artery. MBF and MBV were determined by CMR first-pass perfusion, while the oxygen extraction fraction (OEF) and MVO2 were determined by the myocardial Blood-Oxygen-Level-Dependent (BOLD) effect and Fick’s law, respectively. MR imaging was performed at rest, and during either dipyridamole-induced vasodilation or dobutamine-induced hyperemia. Regional differences in myocardial perfusion and oxygenation were then evaluated. RESULTS Dipyridamole and dobutamine both led to 145–200% increases in MBF and 50–80% increases in MBV in normal perfused myocardium. As expected, MVO2 increased more significantly with dobutamine (~175%) than dipyridamole (~40%). Coronary stenosis resulted in an attenuation of MBF, MBV, and MVO2 in both the LAD-subtended stenosis region and the left circumflex subtended remote region. Liner regression analysis showed that MBV reserve appears to be more correlated with MVO2 reserve during dobutamine stress than MBF reserve, particularly in the stenotic regions. Conversely, MBF reserve appears to be more correlated with MVO2 reserve during dipyridamole, although neither of these differences was significant. CONCLUSIONS Noninvasive evaluation of both myocardial perfusion and oxygenation by CMR facilitates direct monitoring of regional myocardial ischemia and provides a valuable tool for better understanding microvascular pathophysiology. These techniques could complement delayed enhancement and wall motion analysis protocols, making MRI a valuable “one-stop shop” for imaging of myocardial ischemia. PMID:19909936

The successful implantation of continuous-flow left ventricular assist device as a destination therapy in Korea: echocardiographic assessment.

PubMed

Lee, Ga Yeon; Park, Sung-Ji; Kim, Sujin; Choi, Namgyung; Jeong, Dong Seop; Jeon, Eun-Seok; Lee, Young Tak

2014-01-01

Left ventricular assist device (LVAD) is a good treatment option for the patients ineligible for cardiac transplantation. Several studies have demonstrated that a ventricular assist device improves the quality of life and prognosis of the patients with end-stage heart failure. A 75-yr-old man debilitated with New York Heart Association (NYHA) functional class III-IV due to severe left ventricular systolic dysfunction received LVAD implantation as a destination therapy. The patient was discharged with improved functional status (NYHA functional class II) after appropriate cardiac rehabilitation and education about how to manage the device and potential emergency situations. This is the first case of successful continuous-flow LVAD implantation as a destination therapy in Korea.

The role of intraventricular vortices in the left ventricular filling?

NASA Astrophysics Data System (ADS)

Martinez-Legazpi, Pablo; Bermejo, Javier; Benito, Yolanda; Alhama, Marta; Yotti, Raquel; Perez Del Villar, Candelas; Gonzalez-Mansilla, Ana; Barrio, Alicia; Fernandez-Aviles, Francisco; Del Alamo, Juan Carlos

2013-11-01

The generation of vortices during early filling is a salient feature of left ventricular hemodynamics. Existing clinical data suggest that these intraventricular vortices may facilitate pulling flow from the left atrium. To test this hypothesis, we have quantitatively dissected the contribution of the vortex to intraventricular pressure gradients by isolating its induced flow in ultrasound-derived data in 20 patients with non-ischemic dilated cardiomyopathy (NIDCM), 20 age-matched healthy controls and 20 patients with hypertrophied cardiomyopathy. We have observed that, in patients with NIDCM, the hemodynamic forces were shown to be partially supported by the flow inertia whereas that effect was minimized in healthy hearts. In patients with hypertrophied cardiomiopathy such effect was not observed. Supported by grants, PIS09/02603, RD06/0010 (RECAVA), CM12/00273 (to CPV) and BA11/00067 (to JB) from the Instituto de Salud Carlos III, Spain. PML and JCA were partially supported by NIH grant 1R21 HL108268-01.

Mechanical ventilation and thoracic artificial lung assistance during mechanical circulatory support with PUCA pump: in silico study.

PubMed

De Lazzari, Claudio; Genuini, Igino; Quatember, Bernhard; Fedele, Francesco

2014-02-01

Patients assisted with left ventricular assist device (LVAD) may require prolonged mechanical ventilatory assistance secondary to postoperative respiratory failure. The goal of this work is the study of the interdependent effects LVAD like pulsatile catheter (PUCA) pump and mechanical ventilatory support or thoracic artificial lung (TAL), by the hemodynamic point of view, using a numerical simulator of the human cardiovascular system. In the simulator, different circulatory sections are described using lumped parameter models. Lumped parameter models have been designed to describe the hydrodynamic behavior of both PUCA pump and thoracic artificial lung. Ventricular behavior atrial and septum functions were reproduced using variable elastance model. Starting from simulated pathological conditions we studied the effects produced on some hemodynamic variables by simultaneous PUCA pump, thoracic artificial lung or mechanical ventilation assistance. Thoracic artificial lung was applied in parallel or in hybrid mode. The effects of mechanical ventilation have been simulated by changing mean intrathoracic pressure value from -4 mmHg to +5 mmHg. The hemodynamic variables observed during the simulations, in different assisted conditions, were: left and right ventricular end systolic (diastolic) volume, systolic/diastolic aortic pressure, mean pulmonary arterial pressure, left and right mean atrial pressure, mean systemic venous pressure and the total blood flow. Results show that the application of PUCA (without mechanical ventilatory assistance) increases the total blood flow, reduces the left ventricular end systolic volume and increases the diastolic aortic pressure. Parallel TAL assistance increases the right ventricular end diastolic (systolic) volume reduction both when PUCA is switched "ON" and both when PUCA is switched "OFF". By switching "OFF" the PUCA pump, it seems that parallel thoracic artificial lung assistance produces a greater cardiac output (respect to hybrid TAL assistance). Results concerning PUCA and TAL interaction produced by simulations cannot be compared with "in vivo" results since they are not presented in literature. But results concerning the effects produced by LVAD and mechanical ventilation have a trend consistent with those presented in literature. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Congenital left ventricular outpouchings: a systematic review of 839 cases and introduction of a novel classification after two centuries.

PubMed

Malakan Rad, Elaheh; Awad, Sawsan; Hijazi, Ziyad M

2014-01-01

Congenital left ventricular outpouchings (LVOs) are reported under five overlapping and poorly defined terms including left ventricular accessory chamber, left ventricular aneurysm (LVA), left ventricular diverticulum (LVD), double-chambered LV, and accessory left ventricle. Diagnostic criteria are frequently mixed and not mutually exclusive. They convey no information regarding treatment strategy and prognosis. The aim of this systematic review is to provide a clear and inclusive classification, with therapeutic and prognostic implications, for congenital LVOs. We performed three separate sets of search on three subjects including "congenital left ventricular outpouchings," "important and simply measurable markers of left ventricular function," and "relationship of mechanics of intraventricular blood flow and optimal vortex formation in left ventricle and elliptical geometry of LV." We enrolled case series, review articles, and case reports with literature review. All types of acquired LVO's were excluded. We studied the abstracts of all searched articles. We focused on diagnostic criteria and patients' outcome. To examine the validity and reliability of the novel classification, fifteen previous studies were revisited using the novel classification. A total of 20 papers from 11 countries fulfilled our inclusion criteria. The age of patients ranged from prenatal age to geriatric age range. Diagnostic criteria were clearly stated only for two of the above five terms (i.e., congenital LVA and congenital LVD). Cases with mixed diagnostic criteria were frequent.Elliptical geometry of left ventricle was found to have significant impact on effective blood flow mechanics in LV. A simple inclusive classification for congenital LVOs, with therapeutic and prognostic implications, was introduced. The cornerstone of this classification is elliptical LV geometry. Large-type IIc LVO have dismal prognosis, if left untreated. LVO type I and small LVO type IIa have the best prognosis. © 2014 Wiley Periodicals, Inc.

[Gas tamponade following intraoperative pneumothorax on a single lung: A case study].

PubMed

El Jaouhari, S D; Mamane Nassirou, O; Meziane, M; Bensghir, M; Haimeur, C

2017-04-01

Intraoperative pneumothorax is a rare complication with a high risk of cardiorespiratory arrest by gas tamponade especially on a single lung. We report the case of a female patient aged 53 years who benefited from a left pneumonectomy on pulmonary tuberculosis sequelae. The patient presented early postoperative anemia with a left hemothorax requiring an emergency thoracotomy. In perioperative, the patient had a gas tamponade following a pneumothorax of the remaining lung, and the fate has been avoided by an exsufflation. Intraoperative pneumothorax can occur due to lesions of the tracheobronchial airway, of the brachial plexus, the placement of a central venous catheter or barotrauma. The diagnosis of pneumothorax during unipulmonary ventilation is posed by the sudden onset of hypoxia associated with increased airway pressures and hypercapnia. The immediate life-saving procedure involves fine needle exsufflation before the placement of a chest tube. Prevention involves reducing the risk of barotrauma by infusing patients with low flow volumes and the proper use of positive airway pressure, knowing that despite protective ventilation, barotraumas risk still exists. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Patient-specific analysis of blood stasis in the left atrium

NASA Astrophysics Data System (ADS)

Flores, Oscar; Gonzalo, Alejandro; Garcia-Villalba, Manuel; Rossini, Lorenzo; Hsiao, Albert; McVeigh, Elliot; Kahn, Andrew M.; Del Alamo, Juan C.

2016-11-01

Atrial fibrillation (AF) is a common arrhythmia in which the left atrium (LA) beats rapidly and irregularly. Patients with AF are at increased risk of thromboembolic events (TE), particularly stroke. Anticoagulant therapy can reduce the risk of TE in AF, but it can also increase the risks of adverse events such as internal bleeding. The current lack of tools to predict each patient's risk of LA thrombogenesis makes it difficult to decide whether to anticoagulate patients with AF. The aim of this work is to evaluate blood stasis in patient-specific models of the LA, because stasis is a known thrombogenesis risk factor. To achieve our aim, we performed direct numerical simulations of left atrial flow using an immersed boundary solver developed at the UC3M, coupled to a 0D model for the pulmonary circulation. The LA geometry is obtained from time-resolved CT scans and the parameters of the 0D model are found by fitting pulmonary vein flow data obtained by 4D phase contrast MRI. Blood stasis is evaluated from the flow data by computing blood residence time together with other kinematic indices of the velocity field (e.g. strain and kinetic energy). We focus on the flow in the left atrial appendage, including a sensitivity analysis of the effect of the parameters of the 0D model. Funded by the Spanish MECD, the Clinical and Translational Research Institute at UCSD and the American Heart Association.

Development and evaluation of totally implantable ventricular assist system using a vibrating flow pump and transcutaneous energy transmission system with amorphous fibers.

PubMed

Yambe, T; Hashimoto, H; Kobayashi, S; Sonobe, T; Naganuma, S; Nanka, S S; Matsuki, H; Yoshizawa, M; Tabayashi, K; Takayasu, H; Takeda, H; Nitta, S

1997-01-01

We have developed a vibrating flow pump (VFP) that can generate oscillated blood flow with a relatively high frequency (10-50 Hz) for a totally implantable ventricular assist system (VAS). To evaluate the newly developed VAS, left heart bypasses, using the VFP, were performed in chronic animal experiments. Hemodynamic parameters were recorded in a data recorder in healthy adult goats during an awake condition and analyzed in a personal computer system through an alternating-direct current converter. Basic performance of the total system with a transcutaneous energy transmission system were satisfactory. During left ventricular assistance with the VFP, Mayer wave fluctuations of hemodynamics were decreased in the power spectrum, the fractal dimensions of the hemodynamics were significantly decreased, and peripheral vascular resistance was significantly decreased. These results suggest that cardiovascular regulatory nonlinear dynamics, which mediate the hemodynamics, may be affected by left ventricular bypass with oscillated flow. The decreased power of the Mayer wave in the spectrum caused the limit cycle attractor of the hemodynamics and decreased peripheral resistance. These results suggest that this newly developed VAS is useful for the totally implantable system with unique characteristics that can control hemodynamic properties.

Enlarged prostate

MedlinePlus

... gland. Other tests may include: Urine flow rate Post-void residual urine test to see how much urine is left in your bladder after you urinate Pressure-flow studies to measure the pressure in the bladder as ...

Flow Behavior in the Left Heart Ventricle Following Apico-Aortic Bypass Surgery

NASA Astrophysics Data System (ADS)

Shahriari, Shahrokh; Jeyhani, Morteza; Labrosse, Michel; Kadem, Lyes

2013-11-01

Apico-aortic bypass (AAB) surgery is an alternative for transcatheter aortic valve implantation (TAVI) to reduce left ventricle (LV) overload in patients with severe aortic stenosis (AS). It consists in connecting the apex of the LV to the descending thoracic aorta with a valved conduit. Postoperative flow assessments show that two thirds of the outflow is conducted from the LV apex to the conduit, while only one third crosses the native aortic valve. In this study, we performed high speed particle image velocimetry (PIV) measurements of flow pattern within an in vitro elastic model of LV in the presence of a very severe AS, before and after AAB. Results indicate that AAB effectively relieves the LV outflow obstruction; however, it also leads to abnormal ventricular flow patterns. Normal LV flow dynamics is characterized by an emerging mitral jet flow followed by the development of a vortical flow with velocities directed towards the aortic valve, while measurements in the presence of AAB show systolic flow bifurcating to the apical conduit and to the aortic valve outflow tract. This study provides the first insight into the LV flow structure after AAB including outflow jets and disturbed stagnation regions.

Effect of Renin-Angiotensin Blockers on Left Ventricular Remodeling in Severe Aortic Stenosis.

PubMed

Goh, Serene Si-Ning; Sia, Ching-Hui; Ngiam, Nicholas Jinghao; Tan, Benjamin Yong-Qiang; Lee, Poay Sian; Tay, Edgar Lik-Wui; Kong, William Kok-Fai; Yeo, Tiong Cheng; Poh, Kian-Keong

2017-06-01

Studies have shown that medical therapy with renin-angiotensin blockers (RABs) may benefit patients with aortic stenosis (AS). However, its use and efficacy remains controversial, including in patients with low flow (LF) with preserved left ventricular ejection fraction (LVEF). We examined the effects of RAB use on LV remodeling in patients with severe AS with preserved LVEF, analyzing the differential effects in patients with LF compared with normal flow (NF). This is a retrospective study of 428 consecutive subjects from 2005 to 2014 with echocardiographic diagnosis of severe AS and preserved LVEF. Clinical and echocardiographic parameters were systematically collected and analyzed. Two hundred forty-two (57%) patients had LF. Sixty-four LF patients (26%) were treated with RAB. Patients on RAB treatment had a higher incidence of hyperlipidemia (69% vs 44%) and diabetes mellitus (53% vs 34%). Severity of AS in terms of valve area, transvalvular mean pressure gradient, and aortic valve resistance were similar between both groups as was the degree of LV diastolic function. The RAB group demonstrated significantly lower LV mass index with a correspondingly lower incidence of concentric LV hypertrophy. Regardless of the duration of RAB therapy, patients had increased odds of having a preserved LV mass index compared with those without RAB therapy. In conclusion, RAB therapy may be associated with less LV pathological remodeling and have a role in delaying patients from developing cardiovascular complications of AS. Copyright © 2017 Elsevier Inc. All rights reserved.

HaNDL syndrome: Correlation between focal deficits topography and EEG or SPECT abnormalities in a series of 5 new cases.

PubMed

Barón, J; Mulero, P; Pedraza, M I; Gamazo, C; de la Cruz, C; Ruiz, M; Ayuso, M; Cebrián, M C; García-Talavera, P; Marco, J; Guerrero, A L

2016-06-01

Transient headache and neurological deficits with cerebrospinal fluid lymphocytosis (HaNDL) is characterised by migraine-like headache episodes accompanied by neurological deficits consisting of motor, sensory, or aphasic symptoms. Electroencephalogram (EEG) and single photon emission computed tomography (SPECT) may show focal abnormalities that correspond to the neurological deficits. We aim to evaluate the correlation between focal deficit topography and EEG or SPECT abnormalities in 5 new cases. We retrospectively reviewed patients attended in a tertiary hospital (January 2010-May 2014) and identified 5 patients (3 men, 2 women) with a mean age of 30.6 ± 7.7 (21-39) years. They presented 3.4 ± 2.6 episodes of headache (range, 2-8) of moderate to severe intensity and transient neurological deficits over a maximum of 5 weeks. Pleocytosis was detected in CSF in all cases (70 to 312 cells/mm3, 96.5-100% lymphocytes) with negative results from aetiological studies. At least one EEG was performed in 4 patients and SPECT in 3 patients. Patient 1: 8 episodes; 4 left hemisphere, 3 right hemisphere, and 1 brainstem; 2 EEGs showing left temporal and bilateral temporal slowing; normal SPECT. Patient 2: 2 episodes, left hemisphere and right hemisphere; SPECT showed decreased left temporal blood flow. Patient 3: 3 left hemisphere deficits; EEG with bilateral frontal and temporal slowing. Patient 4: 2 episodes with right parieto-occipital topography and right frontal slowing in EEG. Patient 5: 2 episodes, right hemisphere and left hemisphere, EEG with right temporal slowing; normal SPECT. The neurological deficits accompanying headache in HaNDL demonstrate marked clinical heterogeneity. SPECT abnormalities and most of all EEG abnormalities were not uncommon in our series and they did not always correlate to the topography of focal déficits. Copyright © 2014 Sociedad Española de Neurología. Published by Elsevier España, S.L.U. All rights reserved.

Validation of diffuse correlation spectroscopy sensitivity to nicotinamide-induced blood flow elevation in the murine hindlimb using the fluorescent microsphere technique

NASA Astrophysics Data System (ADS)

Proctor, Ashley R.; Ramirez, Gabriel A.; Han, Songfeng; Liu, Ziping; Bubel, Tracy M.; Choe, Regine

2018-03-01

Nicotinamide has been shown to affect blood flow in both tumor and normal tissues, including skeletal muscle. Intraperitoneal injection of nicotinamide was used as a simple intervention to test the sensitivity of noninvasive diffuse correlation spectroscopy (DCS) to changes in blood flow in the murine left quadriceps femoris skeletal muscle. DCS was then compared with the gold-standard fluorescent microsphere (FM) technique for validation. The nicotinamide dose-response experiment showed that relative blood flow measured by DCS increased following treatment with 500- and 1000-mg / kg nicotinamide. The DCS and FM technique comparison showed that blood flow index measured by DCS was correlated with FM counts quantified by image analysis. The results of this study show that DCS is sensitive to nicotinamide-induced blood flow elevation in the murine left quadriceps femoris. Additionally, the results of the comparison were consistent with similar studies in higher-order animal models, suggesting that mouse models can be effectively employed to investigate the utility of DCS for various blood flow measurement applications.

Repeatability, variability and reference values of pulsed wave Doppler echocardiographic measurements in healthy Saanen goats

PubMed Central

2012-01-01

Background Pulsed wave (PW) Doppler echocardiography has become a routine non invasive cardiac diagnostic tool in most species. However, evaluation of intracardiac blood flow requires reference values, which are poorly documented in goats. The aim of this study was to test the repeatability, the variability, and to establish the reference values of PW measurements in healthy adult Saanen goats. Using a standardised PW Doppler echocardiographic protocol, 10 healthy adult unsedated female Saanen goats were investigated three times at one day intervals by the same observer. Mitral, tricuspid, aortic and pulmonary flows were measured from a right parasternal view, and mitral and aortic flows were also measured from a left parasternal view. The difference between left and right side measurements and the intra-observer inter-day repeatability were tested and then the reference values of PW Doppler echocardiographic parameters in healthy adult female Saanen goats were established. Results As documented in other species, all caprine PW Doppler parameters demonstrated a poor inter-day repeatability and a moderate variability. Tricuspid and pulmonary flows were best evaluated on the right side whereas mitral and aortic flows were best obtained on the left side, and reference values are reported for healthy adult Saanen goats. Conclusions PW Doppler echocardiography allows the measurement of intracardiac blood flow indices in goats. The reference values establishment will help interpreting these indices of cardiac function in clinical cardiac cases and developing animal models for human cardiology research. PMID:23067875

Relations of Blood Pressure and Head Injury to Regional Cerebral Blood Flow

PubMed Central

Allen, Allyssa J.; Katzel, Leslie I.; Wendell, Carrington R.; Siegel, Eliot L.; Lefkowitz, David; Waldstein, Shari R.

2016-01-01

Hypertension confers increased risk for cognitive decline, dementia, and cerebrovascular disease. These associations have been attributed, in part, to cerebral hypoperfusion. Here we posit that relations of higher blood pressure to lower levels of cerebral perfusion may be potentiated by a prior head injury. Participants were 87 community-dwelling older adults -69% men, 90% white, mean age= 66.9 years, 27.6% with a history of mild traumatic brain injury (mTBI) defined as a loss of consciousness

Vertebrate Left-Right Asymmetry: What Can Nodal Cascade Gene Expression Patterns Tell Us?

PubMed Central

Schweickert, Axel; Ott, Tim; Kurz, Sabrina; Tingler, Melanie; Maerker, Markus; Fuhl, Franziska; Blum, Martin

2017-01-01

Laterality of inner organs is a wide-spread characteristic of vertebrates and beyond. It is ultimately controlled by the left-asymmetric activation of the Nodal signaling cascade in the lateral plate mesoderm of the neurula stage embryo, which results from a cilia-driven leftward flow of extracellular fluids at the left-right organizer. This scenario is widely accepted for laterality determination in wildtype specimens. Deviations from this norm come in different flavors. At the level of organ morphogenesis, laterality may be inverted (situs inversus) or non-concordant with respect to the main body axis (situs ambiguus or heterotaxia). At the level of Nodal cascade gene activation, expression may be inverted, bilaterally induced, or absent. In a given genetic situation, patterns may be randomized or predominantly lacking laterality (absence or bilateral activation). We propose that the distributions of patterns observed may be indicative of the underlying molecular defects, with randomizations being primarily caused by defects in the flow-generating ciliary set-up, and symmetrical patterns being the result of impaired flow sensing, on the left, the right, or both sides. This prediction, the reasoning of which is detailed in this review, pinpoints functions of genes whose role in laterality determination have remained obscure. PMID:29367579

Noninvasive prediction of left ventricular end-diastolic pressure in patients with coronary artery disease and preserved ejection fraction.

PubMed

Abd-El-Aziz, Tarek A

2012-01-01

The aim of this study was to compare 3 different available methods for estimating left ventricular end-diastolic pressure (LVEDP) noninvasively in patients with coronary artery disease and preserved left ventricular ejection fraction (EF). We used 3 equations for noninvasive estimation of LVEDP: The equation of Mulvagh et al., LVEDP(1) = 46 - 0.22 (IVRT) - 0.10 (AFF) - 0.03 (DT) - (2 ÷ E/A) + 0.05 MAR; the equation of Stork et al., LVEDP(2) = 1.06 + 15.15 × Ai/Ei; and the equation of Abd-El-Aziz, LVEDP(3) = [0.54 (MABP) × (1 - EF)] - 2.23. ( A, A-wave velocity; AFF, atrial filling fraction; Ai, time velocity integral of A wave; DT, deceleration time; E, E-wave velocity; Ei, time velocity integral of E wave; IVRT, isovolumic relaxation time; MABP, mean arterial blood pressure; MAR, time from termination of mitral flow to the electrocardiographic R wave; Ti, time velocity integral of total wave.) LVEDP measured by catheterization was correlated with LVEDP(1) (r = 0.52, P < 0.001), LVEDP(2) (r = 0.31, P < 0.05), and LVEDP(3) (r = 0.81, P < 0.001). The equation described by Abd-El-Aziz, LVEDP = [0.54 MABP × (1 - EF)] - 2.23, appears to be the most accurate, reliable, and easily applied method for estimating LVEDP noninvasively in patients with preserved left ventricular ejection fraction and an LVEDP < 20 mm Hg. Copyright © 2012 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

In vitro evaluation of the effect of aortic compliance on pediatric intra-aortic balloon pumping.

PubMed

Minich, L L; Tani, L Y; Hawkins, J A; Bartkowiak, R R; Royall, M L; Pantalos, G M

2001-04-01

OBJECTIVES: To evaluate the effect of aortic compliance on pediatric intra-aortic balloon pumping (IABP). DESIGN: In vitro study using a mechanical model of the pediatric left heart circulation. SETTING: Cardiovascular fluid dynamics research laboratory. SUBJECT: Pulsatile flow system simulating the pediatric left heart circulation and two different aortas with compliances comparable to those of the pediatric aorta (0.12 and 0.07 mL/mm Hg). INTERVENTIONS: Measurements were made at a baseline peak aortic flow of 4 L/min, at simulated shock (1.7 L/min), and with 1:1 IABP (rates, 130 and 150 bpm; balloon volumes, 2.5 and 5.0 mL). MEASUREMENTS AND MAIN RESULTS: Peak flow rates were measured in the ascending aorta, coronary arterial system, and brachiocephalic arterial systems. Aortic pressure was measured in the ascending aorta. For both aortas (0.12 and 0.07 mL/mm Hg), IABP resulted in diastolic augmentation (38 +/- 8 and 43 +/- 16 mm Hg) and afterload reduction (4 +/- 2 and 6 +/- 3 mm Hg). For both aortas, compared to shock, IABP resulted in significant increases in coronary arterial and brachiocephalic arterial flow and aortic pressure for both aortas. Aortic flow significantly increased only in the less-compliant aorta. CONCLUSIONS: In a laboratory model of pediatric left heart circulation, IABP results in diastolic augmentation, afterload reduction, and improved hemodynamics, even in aortas of greater compliance.

Left Gastric Vein Visualization with Hepatopetal Flow Information in Healthy Subjects Using Non-Contrast-Enhanced Magnetic Resonance Angiography with Balanced Steady-State Free-Precession Sequence and Time-Spatial Labeling Inversion Pulse.

PubMed

Furuta, Akihiro; Isoda, Hiroyoshi; Ohno, Tsuyoshi; Ono, Ayako; Yamashita, Rikiya; Arizono, Shigeki; Kido, Aki; Sakashita, Naotaka; Togashi, Kaori

2018-01-01

To selectively visualize the left gastric vein (LGV) with hepatopetal flow information by non-contrast-enhanced magnetic resonance angiography under a hypothesis that change in the LGV flow direction can predict the development of esophageal varices; and to optimize the acquisition protocol in healthy subjects. Respiratory-gated three-dimensional balanced steady-state free-precession scans were conducted on 31 healthy subjects using two methods (A and B) for visualizing the LGV with hepatopetal flow. In method A, two time-spatial labeling inversion pulses (Time-SLIP) were placed on the whole abdomen and the area from the gastric fornix to the upper body, excluding the LGV area. In method B, nonselective inversion recovery pulse was used and one Time-SLIP was placed on the esophagogastric junction. The detectability and consistency of LGV were evaluated using the two methods and ultrasonography (US). Left gastric veins by method A, B, and US were detected in 30 (97%), 24 (77%), and 23 (74%) subjects, respectively. LGV flow by US was hepatopetal in 22 subjects and stagnant in one subject. All hepatopetal LGVs by US coincided with the visualized vessels in both methods. One subject with non-visualized LGV in method A showed stagnant LGV by US. Hepatopetal LGV could be selectively visualized by method A in healthy subjects.

F-16XL Ship #2 during last flight showing titanium laminar flow glove on left wing

NASA Technical Reports Server (NTRS)

1996-01-01

The perforated titanium overlay mounted on the upper surface of the left wing is clearly evident on this view of NASA 848, a highly modified F-16XL aircraft flown by NASA's Dryden Flight Research Center in the Supersonic Laminar Flow Control (SLFC) research program. The two-seat, single-engine craft, one of only two 'XL' F-16s built, recently concluded the SLFC project with its 45th data collection mission. The project demonstrated that laminar--or smooth--airflow could be achieved over a major portion of a wing at supersonic speeds by use of a suction system. The system drew a small part of the boundary-layer air through millions of tiny laser-drilled holes in the 'glove' fitted to the upper left wing.

Left Atrial Pressure Monitoring With an Implantable Wireless Pressure Sensor After Implantation of a Left Ventricular Assist Device

PubMed Central

Baranowski, Jacek; Delshad, Baz; Ahn, Henrik

2017-01-01

After implantation of a continuous-flow left ventricular assist device (LVAD), left atrial pressure (LAP) monitoring allows for the precise management of intravascular volume, inotropic therapy, and pump speed. In this case series of 4 LVAD recipients, we report the first clinical use of this wireless pressure sensor for the long-term monitoring of LAP during LVAD support. A wireless microelectromechanical system pressure sensor (Titan, ISS Inc., Ypsilanti, MI) was placed in the left atrium in four patients at the time of LVAD implantation. Titan sensor LAP was measured in all four patients on the intensive care unit and in three patients at home. Ramped speed tests were performed using LAP and echocardiography in three patients. The left ventricular end-diastolic diameter (cm), flow (L/min), power consumption (W), and blood pressure (mm Hg) were measured at each step. Measurements were performed over 36, 84, 137, and 180 days, respectively. The three discharged patients had equipment at home and were able to perform daily recordings. There were significant correlations between sensor pressure and pump speed, LV and LA size and pulmonary capillary wedge pressure, respectively (r = 0.92–0.99, p < 0.05). There was no device failure, and there were no adverse consequences of its use. PMID:27676410

Plastic brain mechanisms for attaining auditory temporal order judgment proficiency.

PubMed

Bernasconi, Fosco; Grivel, Jeremy; Murray, Micah M; Spierer, Lucas

2010-04-15

Accurate perception of the order of occurrence of sensory information is critical for the building up of coherent representations of the external world from ongoing flows of sensory inputs. While some psychophysical evidence reports that performance on temporal perception can improve, the underlying neural mechanisms remain unresolved. Using electrical neuroimaging analyses of auditory evoked potentials (AEPs), we identified the brain dynamics and mechanism supporting improvements in auditory temporal order judgment (TOJ) during the course of the first vs. latter half of the experiment. Training-induced changes in brain activity were first evident 43-76 ms post stimulus onset and followed from topographic, rather than pure strength, AEP modulations. Improvements in auditory TOJ accuracy thus followed from changes in the configuration of the underlying brain networks during the initial stages of sensory processing. Source estimations revealed an increase in the lateralization of initially bilateral posterior sylvian region (PSR) responses at the beginning of the experiment to left-hemisphere dominance at its end. Further supporting the critical role of left and right PSR in auditory TOJ proficiency, as the experiment progressed, responses in the left and right PSR went from being correlated to un-correlated. These collective findings provide insights on the neurophysiologic mechanism and plasticity of temporal processing of sounds and are consistent with models based on spike timing dependent plasticity. Copyright 2010 Elsevier Inc. All rights reserved.

Feasibility and Safety of Distal and Proximal Combined Endovascular Approach with a Balloon-Guiding Catheter for Subclavian Artery Total Occlusion.

PubMed

Yamamoto, Taiki; Ohshima, Tomotaka; Ishikawa, Kojiro; Goto, Shunsaku; Tamari, Yosuke

2017-04-01

Symptomatic subclavian artery total occlusion is widely treated with an endovascular procedure that often results in distal vertebral artery embolism. Therefore, protection devices are important. Establishing a filter or balloon device in the vertebral artery can protect against this distal embolism. However, the use of embolic protection devices is not easy, and it makes the procedure more complicated. Here, we report a case of symptomatic subclavian artery total occlusion that was treated successfully with a balloon-guiding catheter and the pull-through technique. A 67-year-old man developed intermittent motor weakness in his left arm. Aortic angiography demonstrated a complete occlusion of the left proximal subclavian artery and a retrograde flow through the left vertebral artery to the distal brachial artery. In this case, we used a balloon-guiding catheter and the pull-through technique to prevent distal embolism. The balloon-guiding system was useful not only for embolic protection but also for scaffold during excavation and for the centering effect against invisible vessels. The pull-through technique enabled our devices to deliver easily and smoothly. The patient was treated successfully without complications. The distal and proximal combined endovascular treatment with a transbrachial balloon-guiding catheter is a beneficial treatment option for patients with subclavian artery total occlusion. Copyright © 2017 Elsevier Inc. All rights reserved.

Cor triatriatum sinister identified after new onset atrial fibrillation in an elderly man.

PubMed

Zepeda, Ignacio A; Morcos, Peter; Castellanos, Luis R

2014-01-01

A 73-year-old man with new onset atrial fibrillation with rapid ventricular response underwent transthoracic echocardiography that revealed an echogenic linear structure along the left atrium, suggestive of cor triatriatum sinister (CTS). CTS was confirmed with transesophageal echocardiography which demonstrated a proximal accessory atrium receiving pulmonary venous flow separated from a distal true atrium by a fibromuscular membrane with a large fenestration allowing flow between the chambers. In CTS, the left atrium is divided into proximal and distal chambers by a fenestrated fibromuscular septum. This cardiac anomaly accounts for 0.1% of cases of congenital heart disease and rarely presents in adults. CTS is primarily diagnosed with echocardiography and is associated with left atrial enlargement and development of atrial fibrillation. Treatment options depend on size of the communication between proximal and distal chambers, the gradient across the membrane, and the position of pulmonary veins. In some instances, surgical resection of the membrane that divides the left atrium is warranted.

Cor Triatriatum Sinister Identified after New Onset Atrial Fibrillation in an Elderly Man

PubMed Central

Zepeda, Ignacio A.; Morcos, Peter; Castellanos, Luis R.

2014-01-01

A 73-year-old man with new onset atrial fibrillation with rapid ventricular response underwent transthoracic echocardiography that revealed an echogenic linear structure along the left atrium, suggestive of cor triatriatum sinister (CTS). CTS was confirmed with transesophageal echocardiography which demonstrated a proximal accessory atrium receiving pulmonary venous flow separated from a distal true atrium by a fibromuscular membrane with a large fenestration allowing flow between the chambers. In CTS, the left atrium is divided into proximal and distal chambers by a fenestrated fibromuscular septum. This cardiac anomaly accounts for 0.1% of cases of congenital heart disease and rarely presents in adults. CTS is primarily diagnosed with echocardiography and is associated with left atrial enlargement and development of atrial fibrillation. Treatment options depend on size of the communication between proximal and distal chambers, the gradient across the membrane, and the position of pulmonary veins. In some instances, surgical resection of the membrane that divides the left atrium is warranted. PMID:25614746

Regional cerebral blood flow (rCBF) in schizophrenia during verbal memory activation: a 99mTc-HMPAO single photon emission tomography (SPET) study.

PubMed

Busatto, G F; Costa, D C; Ell, P J; Pilowsky, L S; David, A S; Kerwin, R W

1994-05-01

Regional cerebral blood flow (rCBF) was investigated in a group of medicated DSM-III-R schizophrenic patients and age, sex and handedness matched normal volunteers using a split-dose 99mTc-HMPAO Single Photon Emission Tomography (SPET) protocol. Measures were taken during the performance of a verbal memory task aimed at activating the left medial temporal lobe, a region repeatedly suggested to be structurally abnormal in schizophrenia. In normal subjects, the performance of the task was associated with significant rCBF increases in the left medial temporal, left inferior frontal and anterior cingulate cortices, and right cerebellum. Despite their significantly poorer performance on the memory task, the degree of medial temporal activation measured in the schizophrenic patients was not significantly different from that found in the control group. This finding suggests that memory deficits in schizophrenia do not necessarily imply failure to activate the left medial temporal lobe as assessed by 99mTc-HMPAO SPET.

Effect of the mitral valve on diastolic flow patterns

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seo, Jung Hee; Vedula, Vijay; Mittal, Rajat, E-mail: mittal@jhu.edu

2014-12-15

The leaflets of the mitral valve interact with the mitral jet and significantly impact diastolic flow patterns, but the effect of mitral valve morphology and kinematics on diastolic flow and its implications for left ventricular function have not been clearly delineated. In the present study, we employ computational hemodynamic simulations to understand the effect of mitral valve leaflets on diastolic flow. A computational model of the left ventricle is constructed based on a high-resolution contrast computed-tomography scan, and a physiological inspired model of the mitral valve leaflets is synthesized from morphological and echocardiographic data. Simulations are performed with a diodemore » type valve model as well as the physiological mitral valve model in order to delineate the effect of mitral-valve leaflets on the intraventricular flow. The study suggests that a normal physiological mitral valve promotes the formation of a circulatory (or “looped”) flow pattern in the ventricle. The mitral valve leaflets also increase the strength of the apical flow, thereby enhancing apical washout and mixing of ventricular blood. The implications of these findings on ventricular function as well as ventricular flow models are discussed.« less

Left Ventricular Myocardial Deformation Parameters Are Affected by Coronary Slow Flow Phenomenon: A Study of Speckle Tracking Echocardiography.

PubMed

Gulel, Okan; Akcay, Murat; Soylu, Korhan; Aksan, Gokhan; Yuksel, Serkan; Zengin, Halit; Meric, Murat; Sahin, Mahmut

2016-05-01

The coronary slow flow phenomenon (CSFP) is defined as a delayed distal vessel contrast opacification in the absence of obstructive epicardial coronary artery disease during coronary angiography. There is conflicting data in medical literature regarding the effects of CSFP on the left ventricular functions assessed by conventional echocardiography or tissue Doppler imaging. Therefore, we aimed to evaluate whether there is any abnormality in the myocardial deformation parameters (strain, strain rate (SR), rotation, twist) of the left ventricle obtained by speckle tracking echocardiography (STE) in patients with CSFP. Twenty patients with CSFP were included prospectively in the study. Another 20 patients with similar demographics and cardiovascular risk factors as well as normal coronary angiography were used as the control group. Two-dimensional echocardiographic images of the left ventricle from the apical long-axis, two-chamber, four-chamber, and parasternal short-axis views were used for STE analysis. The analysis of left ventricular circumferential deformation parameters showed that the averaged peak systolic strain, systolic SR, and early diastolic SR values were significantly lower in patients with CSFP (P = 0.009, P = 0.02, and P = 0.02, respectively). Among the left ventricular rotation and twist values, apical rotation was significantly lower in patients with CSFP (P = 0.02). Further, the mean thrombolysis in myocardial infarction frame count value was found to be negatively correlated with the averaged peak circumferential early diastolic SR (r = -0.35, P = 0.03). It was positively correlated with the averaged peak circumferential systolic strain (r = 0.47, P = 0.003) and circumferential systolic SR (r = 0.46, P = 0.005). Coronary slow flow phenomenon leads to significant alterations in the myocardial deformation parameters of the left ventricle as assessed by STE. Specifically, circumferential deformation parameters are affected in CSFP patients. © 2015, Wiley Periodicals, Inc.

Prospective assessment of the frequency of low gradient severe aortic stenosis with preserved left ventricular ejection fraction: Critical impact of aortic flow misalignment and pressure recovery phenomenon.

PubMed

Ringle, Anne; Castel, Anne-Laure; Le Goffic, Caroline; Delelis, François; Binda, Camille; Bohbot, Yohan; Ennezat, Pierre Vladimir; Guerbaai, Raphaëlle A; Levy, Franck; Vincentelli, André; Graux, Pierre; Tribouilloy, Christophe; Maréchaux, Sylvestre

2018-02-10

The frequency of paradoxical low-gradient severe aortic stenosis (AS) varies widely across studies. The impact of misalignment of aortic flow and pressure recovery phenomenon on the frequency of low-gradient severe AS with preserved left ventricular ejection fraction (LVEF) has not been evaluated in prospective studies. To investigate prospectively the impact of aortic flow misalignment by Doppler and lack of pressure recovery phenomenon correction on the frequency of low-gradient (LG) severe aortic stenosis (AS) with preserved LVEF. Aortic jet velocities and mean pressure gradient (MPG) were obtained by interrogating all windows in 68 consecutive patients with normal LVEF and severe AS (aortic valve area [AVA] ≤1cm 2 ) on the basis of the apical imaging window alone (two-dimensional [2D] apical approach). Patients were classified as having LG or high-gradient (HG) AS according to MPG <40mmHg or ≥40mmHg, and normal flow (NF) or low flow (LF) according to stroke volume index >35mL/m 2 or ≤35mL/m 2 , on the basis of the 2D apical approach, the multiview approach (multiple windows evaluation) and AVA corrected for pressure recovery. The proportion of LG severe AS was 57% using the 2D apical approach alone. After the multiview approach and correction for pressure recovery, the proportion of LG severe AS decreased from 57% to 13% (LF-LG severe AS decreased from 23% to 3%; NF-LG severe AS decreased from 34% to 10%). As a result, 25% of patients were reclassified as having HG severe AS (AVA ≤1cm 2 and MPG ≥40mmHg) and 19% as having moderate AS. Hence, 77% of patients initially diagnosed with LG severe AS did not have "true" LG severe AS when the multiview approach and the pressure recovery phenomenon correction were used. Aortic flow misevaluation, resulting from lack of use of multiple windows evaluation and pressure recovery phenomenon correction, accounts for a large proportion of incorrectly graded AS and considerable overestimation of the frequency of LG severe AS with preserved LVEF. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Ventricular kinetic energy may provide a novel noninvasive way to assess ventricular performance in patients with repaired tetralogy of Fallot.

PubMed

Jeong, Daniel; Anagnostopoulos, Petros V; Roldan-Alzate, Alejandro; Srinivasan, Shardha; Schiebler, Mark L; Wieben, Oliver; François, Christopher J

2015-05-01

Ventricular kinetic energy measurements may provide a novel imaging biomarker of declining ventricular efficiency in patients with repaired tetralogy of Fallot. Our purpose was to assess differences in ventricular kinetic energy with 4-dimensional flow magnetic resonance imaging between patients with repaired tetralogy of Fallot and healthy volunteers. Cardiac magnetic resonance, including 4-dimensional flow magnetic resonance imaging, was performed at rest in 10 subjects with repaired tetralogy of Fallot and 9 healthy volunteers using clinical 1.5T and 3T magnetic resonance imaging scanners. Right and left ventricular kinetic energy (KERV and KELV), main pulmonary artery flow (QMPA), and aortic flow (QAO) were quantified using 4-dimensional flow magnetic resonance imaging data. Right and left ventricular size and function were measured using standard cardiac magnetic resonance techniques. Differences in peak systolic KERV and KELV in addition to the QMPA/KERV and QAO/KELV ratios between groups were assessed. Kinetic energy indices were compared with conventional cardiac magnetic resonance parameters. Peak systolic KERV and KELV were higher in patients with repaired tetralogy of Fallot (6.06 ± 2.27 mJ and 3.55 ± 2.12 mJ, respectively) than in healthy volunteers (5.47 ± 2.52 mJ and 2.48 ± 0.75 mJ, respectively), but were not statistically significant (P = .65 and P = .47, respectively). The QMPA/KERV and QAO/KELV ratios were lower in patients with repaired tetralogy of Fallot (7.53 ± 5.37 mL/[cycle mJ] and 9.65 ± 6.61 mL/[cycle mJ], respectively) than in healthy volunteers (19.33 ± 18.52 mL/[cycle mJ] and 35.98 ± 7.66 mL/[cycle mJ], respectively; P < .05). QMPA/KERV and QAO/KELV were weakly correlated to ventricular size and function. Greater ventricular kinetic energy is necessary to generate flow in the pulmonary and aortic circulations in repaired tetralogy of Fallot. Quantification of ventricular kinetic energy in patients with repaired tetralogy of Fallot is a new observation. Future studies are needed to determine whether changes in ventricular kinetic energy can provide earlier evidence of ventricular dysfunction and guide future medical and surgical interventions. Copyright © 2015 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

Clinical impact of quantitative left atrial vortex flow analysis in patients with atrial fibrillation: a comparison with invasive left atrial voltage mapping.

PubMed

Lee, Jung Myung; Hong, Geu-Ru; Pak, Hui-Nam; Shim, Chi Young; Houle, Helene; Vannan, Mani A; Kim, Minji; Chung, Namsik

2015-08-01

Recently, left atrial (LA) vortex flow analysis using contrast transesophageal echocardiography (TEE) has been shown to be feasible and has demonstrated significant differences in vortex flow morphology and pulsatility between normal subjects and patients with atrial fibrillation (AF). However, the relationship between LA vortex flow and electrophysiological properties and the clinical significance of LA vortex flow are unknown. The aims of this study were (1) to compare LA vortex flow parameters with LA voltage and (2) to assess the predictive value of LA vortex flow parameters for the recurrence of AF after radiofrequency catheter ablation (RFCA). Thirty-nine patients with symptomatic non-valvular AF underwent contrast TEE before undergoing RFCA for AF. Quantitative LA vortex flow parameters were analyzed by Omega flow (Siemens Medical Solution, Mountain View, CA, USA). The morphology and pulsatility of LA vortex flow were compared with electrophysiologic parameters that were measured invasively. Hemodynamic, electrophysiological, and vortex flow parameters were compared between patients with and without early recurrence of AF after RFCA. Morphologic parameters, including LA vortex depth, length, width, and sphericity index were not associated with LA voltage or hemodynamic parameters. The relative strength (RS), which represents the pulsatility power of LA, was positively correlated with LA voltage (R = 0.53, p = 0.01) and LA appendage flow velocity (R = 0.73, p < 0.001) and negatively correlated with LA volume index (R = -0.56, p < 0.001). Patients with recurrent AF after RFCA showed significantly lower RS (1.7 ± 0.2 vs 1.9 ± 0.4, p = 0.048) and LA voltage (0.9 ± 0.7 vs 1.7 ± 0.8, p = 0.004) than patients without AF recurrence. In the relatively small LA dimension group (LA volume index ≤ 33 ml/m(2)), RS was significantly lower (2.1 ± 0.3 vs 1.7 ± 0.1, p = 0.029) in patients with the recurrent AF. Quantitative LA vortex flow analysis, especially RS, correlated well with LA voltage. Decreased pulsatility strength in the LA was associated with recurrent AF. LA vortex may have incremental value in predicting the recurrence of AF.

Short-time-scale left ventricular systolic dynamics. Evidence for a common mechanism in both left ventricular chamber and heart muscle mechanics.

PubMed

Campbell, K B; Shroff, S G; Kirkpatrick, R D

1991-06-01

Based on the premise that short-time-scale, small-amplitude pressure/volume/outflow behavior of the left ventricular chamber was dominated by dynamic processes originating in cardiac myofilaments, a prototype model was built to predict pressure responses to volume perturbations. In the model, chamber pressure was taken to be the product of the number of generators in a pressure-bearing state and their average volumetric distortion, as in the muscle theory of A.F. Huxley, in which force was equal to the number of attached crossbridges and their average lineal distortion. Further, as in the muscle theory, pressure generators were assumed to cycle between two states, the pressure-bearing state and the non-pressure-bearing state. Experiments were performed in the isolated ferret heart, where variable volume decrements (0.01-0.12 ml) were removed at two commanded flow rates (flow clamps, -7 and -14 ml/sec). Pressure responses to volume removals were analyzed. Although the prototype model accounted for most features of the pressure responses, subtle but systematic discrepancies were observed. The presence or absence of flow and the magnitude of flow affected estimates of model parameters. However, estimates of parameters did not differ when the model was fitted to flow clamps with similar magnitudes of flows but different volume changes. Thus, prototype model inadequacies were attributed to misrepresentations of flow-related effects but not of volume-related effects. Based on these discrepancies, an improved model was built that added to the simple two-state cycling scheme, a pathway to a third state. This path was followed only in response to volume change. The improved model eliminated the deficiencies of the prototype model and was adequate in accounting for all observations. Since the template for the improved model was taken from the cycling crossbridge theory of muscle contraction, it was concluded that, in spite of the complexities of geometry, architecture, and regional heterogeneity of function and structure, crossbridge mechanisms dominated the short-time-scale dynamics of left ventricular chamber behavior.

Computational fluid dynamics simulation of airflow in the trachea and main bronchi for the subjects with left pulmonary artery sling

PubMed Central

2014-01-01

Background Left pulmonary artery sling (LPAS) is a rare but severe congenital anomaly, in which the stenoses are formed in the trachea and/or main bronchi. Multi-detector computed tomography (MDCT) provides useful anatomical images, but does not offer functional information. The objective of the present study is to quantitatively analyze the airflow in the trachea and main bronchi of LPAS subjects through computational fluid dynamics (CFD) simulation. Methods Five subjects (four LPAS patients, one normal control) aging 6-19 months are analyzed. The geometric model of the trachea and the two main bronchi is extracted from the MDCT images. The inlet velocity is determined based on the body weight and the inlet area. Both the geometric model and personalized inflow conditions are imported into CFD software, ANSYS. The pressure drop, mass flow ratio through two bronchi, wall pressure, flow velocity and wall shear stress (WSS) are obtained, and compared to the normal control. Results Due to the tracheal and/or bronchial stenosis, the pressure drop for the LPAS patients ranges 78.9 - 914.5 Pa, much higher than for the normal control (0.7 Pa). The mass flow ratio through the two bronchi does not correlate with the sectional area ratio if the anomalous left pulmonary artery compresses the trachea or bronchi. It is suggested that the C-shaped trachea plays an important role on facilitating the air flow into the left bronchus with the inertia force. For LPAS subjects, the distributions of velocities, wall pressure and WSS are less regular than for the normal control. At the stenotic site, high velocity, low wall pressure and high WSS are observed. Conclusions Using geometric models extracted from CT images and the patient-specified inlet boundary conditions, CFD simulation can provide vital quantitative flow information for LPAS. Due to the stenosis, high pressure drops, inconsistent distributions of velocities, wall pressure and WSS are observed. The C-shaped trachea may facilitate a larger flow of air into the left bronchus under the inertial force, and decrease the ventilation of the right lung. Quantitative and personalized information may help understand the mechanism of LPAS and the correlations between stenosis and dyspnea, and facilitate the structural and functional assessment of LPAS. PMID:24957947

Patient-specific CFD simulation of intraventricular haemodynamics based on 3D ultrasound imaging.

PubMed

Bavo, A M; Pouch, A M; Degroote, J; Vierendeels, J; Gorman, J H; Gorman, R C; Segers, P

2016-09-09

The goal of this paper is to present a computational fluid dynamic (CFD) model with moving boundaries to study the intraventricular flows in a patient-specific framework. Starting from the segmentation of real-time transesophageal echocardiographic images, a CFD model including the complete left ventricle and the moving 3D mitral valve was realized. Their motion, known as a function of time from the segmented ultrasound images, was imposed as a boundary condition in an Arbitrary Lagrangian-Eulerian framework. The model allowed for a realistic description of the displacement of the structures of interest and for an effective analysis of the intraventricular flows throughout the cardiac cycle. The model provides detailed intraventricular flow features, and highlights the importance of the 3D valve apparatus for the vortex dynamics and apical flow. The proposed method could describe the haemodynamics of the left ventricle during the cardiac cycle. The methodology might therefore be of particular importance in patient treatment planning to assess the impact of mitral valve treatment on intraventricular flow dynamics.

Coil occlusion of residual shunts after surgical closure of patent ductus arteriosus.

PubMed

Fujii, Yoko; Keene, Bruce W; Mathews, Kyle G; Atkins, Clarke E; Defrancesco, Teresa C; Hardie, Elizabeth M; Wakao, Yoshito

2006-12-01

OBJECTIVE; To describe use of coil embolization to occlude residual flow through a patent ductus arteriosus (PDA) after incomplete surgical ligation. Clinical study. Dogs (n=4) with continuous murmur after surgical ligation of PDA. After PDA ligation, residual ductal flow through the PDA was visible on color-flow Doppler examination and left ventricular end-diastolic diameter remained increased. Coil embolization by an arterial approach was performed to achieve complete occlusion of the PDA. Embolization coils were delivered without complications and hemodynamically successful occlusion was achieved. Doppler-visible flow resolved in 2 dogs within 3 months after embolization. Left ventricular end-diastolic diameter indexed to body weight decreased in all dogs. Transcatheter coil embolization appears to be a safe and minimally invasive procedure for complete occlusion of residual PDA flow after incomplete surgical ligation. Transcatheter coil embolization should be considered for correction of hemodynamically significant residual shunts in dogs that have incomplete PDA occlusion after open surgical ligation.

Differential expression of pro-inflammatory cytokines in intra-epithelial T cells between trachea and bronchi distinguishes severity of COPD.

PubMed

Hodge, Greg; Reynolds, Paul N; Holmes, Mark; Hodge, Sandra

2012-12-01

Measuring T-cell production of intracellular cytokines by flow cytometry enables specific monitoring of airway inflammation and response to therapies in chronic lung diseases including chronic obstructive pulmonary disease (COPD). We have previously shown that T cells in the airways of ex- and current- smoker COPD patients and healthy smokers produce increased T-cell pro-inflammatory cytokines IFNγ and TNFα versus healthy controls. However, we could not differentiate between COPD groups and smokers due to a high degree of inter-patient variability. To address this limitation, we hypothesized that intraepithelial T cells obtained from brushings of trachea may serve as an ideal intra-patient control compared with cells obtained from left and right bronchi. Production of intracellular cytokines by intraepithelial T-cells obtained from trachea and right and left bronchi from 26 individuals with COPD (16 with GOLD I and 10 with GOLD II-III disease), 11 healthy controls and 8 smokers was measured by flow cytometry. There was a significant increase in intraepithelial T-cell IFNγ and TNFα in both right and left bronchi of GOLD II-III COPD patients compared to cells obtained from the trachea. There were no changes in T cell pro-inflammatory cytokines between the bronchi and trachea from control subjects, GOLD I COPD patients or healthy smokers. There was a significant negative correlation between increased intraepithelial IFNγ and TNFα in bronchial brushing T-cells compared with tracheal T-cells, and compared with FEV1. Monitoring intracellular intra-epithelial T-cell cytokine production in bronchial brushings using autologous tracheal brushings as controls provides improves the sensitivity of the technique. Therapeutic targeting of these pro-inflammatory cytokines and assessing the effects of drugs on immune reactivity has the potential to reduce lung inflammation caused by intra-epithelial T cells in COPD. Copyright © 2012 Elsevier Ltd. All rights reserved.

Outcome and Impact of Aortic Valve Replacement in Patients With Preserved LVEF and Low-Gradient Aortic Stenosis.

PubMed

Dayan, Victor; Vignolo, Gustavo; Magne, Julien; Clavel, Marie-Annick; Mohty, Dania; Pibarot, Philippe

2015-12-15

Low mean transvalvular gradient (<40 mm Hg) and small aortic valve area (<1.0 cm(2)) in patients with aortic stenosis (AS) and preserved left ventricular ejection fraction raises uncertainty about the actual severity of the stenosis and survival benefit of aortic valve replacement (AVR). This study analyzed studies of mortality and survival impact of AVR in patients with low-gradient (LG) AS and preserved left ventricular ejection fraction, including paradoxical low-flow (i.e., stroke volume index <35 ml/m(2)), low-gradient (LF-LG) and normal-flow, low-gradient (NF-LG), and those with high-gradient (≥ 40 mm Hg) AS or moderate AS. Studies published between 2005 and 2015 were analyzed. Primary outcome was the survival benefit associated with AVR. Secondary outcome was overall mortality regardless of treatment. Eighteen studies were included in the analysis. Patients with LF-LG AS have increased mortality compared with patients with moderate AS (hazard ratio [HR]: 1.68; 95% confidence interval [CI]: 1.31 to 2.17), NF-LG (HR: 1.80; 95% CI: 1.29 to 2.51), and high-gradient (HR: 1.67; 95% CI: 1.16 to 2.39) AS. AVR was associated with reduced mortality in patients with LF-LG (HR: 0.44; 95% CI: 0.25 to 0.77). Similar benefit occurred with AVR in patients with NF-LG (HR: 0.48; 95% CI: 0.28 to 0.83). Compared with patients with high-gradient AS, those with LF-LG were less likely to be referred to AVR (odds ratio: 0.32; 95% CI: 0.21 to 0.49). Patients with paradoxical LF-LG AS and NF-LG AS have increased risk of mortality compared with other subtypes of AS with preserved left ventricular ejection fraction, and improved outcome with AVR. Copyright © 2015 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Coronary flow reserve/diastolic function relationship in angina-suffering patients with normal coronary angiography.

PubMed

Anchisi, Chiara; Marti, Giuliano; Bellacosa, Ilaria; Mary, David; Vacca, Giovanni; Marino, Paolo; Grossini, Elena

2017-05-01

Coronary blood flow and diastolic function are well known to interfere with each other through mechanical and metabolic mechanisms. We aimed to assess the relationship between coronary flow reserve (CFR) and diastolic dysfunction in patients suffering from angina but with normal coronary angiography. In 16 patients with chest pain and angiographically normal coronary arteries, CFR was measured using transthoracic echo-Doppler by inducing hyperemia through dipyridamole infusion. Diastolic function (E/A, deceleration time, isovolumetric relaxation time [IVRT], propagation velocity [Vp]) and left ventricular mass were evaluated by means of two-dimensional transthoracic echocardiography. The patients were initially divided into two groups on the grounds of CFR only (ACFR: altered CFR, n = 9; NACFR: unaltered CFR, n = 7). Thereafter they were divided into four groups on the grounds of CFR and diastolic function (NN: normal; AA: altered CFR/diastole; AN: altered CFR/normal diastole; NA: normal CFR/altered diastole). Most of the subjects were scheduled in AA (n = 8) or NA (n = 5) groups, which were taken into consideration for further analysis. Patients were not different regarding various risk factors. ACFR and AA patients were older with normal body weight in comparison with NACFR and NA patients (P < 0.05). In the AA group, CFR and diastolic variables were found to be related to each other. Diastolic dysfunction and reduced CFR were correlated in patients with concomitant alterations of those variables only. Because most risk factors were shared with patients with altered diastolic properties only, our findings could represent a direct relationship between altered CFR and diastole.

Doppler-guided retrograde catheterization system

NASA Astrophysics Data System (ADS)

Frazin, Leon J.; Vonesh, Michael J.; Chandran, Krishnan B.; Khasho, Fouad; Lanza, George M.; Talano, James V.; McPherson, David D.

1991-05-01

The purpose of this study was to investigate a Doppler guided catheterization system as an adjunctive or alternative methodology to overcome the disadvantages of left heart catheterization and angiography. These disadvantages include the biological effects of radiation and the toxic and volume effects of iodine contrast. Doppler retrograde guidance uses a 20 MHz circular pulsed Doppler crystal incorporated into the tip of a triple lumen multipurpose catheter and is advanced retrogradely using the directional flow information provided by the Doppler waveform. The velocity detection limits are either 1 m/second or 4 m/second depending upon the instrumentation. In a physiologic flow model of the human aortic arch, multiple data points revealed a positive wave form when flow was traveling toward the catheter tip indicating proper alignment for retrograde advancement. There was a negative wave form when flow was traveling away from the catheter tip if the catheter was in a branch or bent upon itself indicating improper catheter tip position for retrograde advancement. In a series of six dogs, the catheter was able to be accurately advanced from the femoral artery to the left ventricular chamber under Doppler signal guidance without the use of x-ray. The potential applications of a Doppler guided retrograde catheterization system include decreasing time requirements and allowing safer catheter guidance in patients with atherosclerotic vascular disease and suspected aortic dissection. The Doppler system may allow left ventricular pressure monitoring in the intensive care unit without the need for x-ray and it may allow left sided contrast echocardiography. With pulse velocity detection limits of 4 m/second, this system may allow catheter direction and passage into the aortic root and left ventricle in patients with aortic stenosis. A modification of the Doppler catheter may include transponder technology which would allow precise catheter tip localization once the catheter tip is placed in the aortic root. Such technology may conceivably assist in allowing selective coronary catheterization. These studies have demonstrated that Doppler guided retrograde catheterization provides an accurate method to catheterization the aortic root and left ventricular chamber without x-ray. In humans, it may prove useful in a variety of settings including the development of invasive ultrasonic diagnostic and therapeutic technology.

Wind and Lava

NASA Image and Video Library

2006-11-27

In this image wind seems to be the dominant process, but lava flows are still recognizable from the surface texture. It appears that the lava flow top left is relatively thin, and the material below is easily eroded by the wind

2. CATCH BASIN, INFLOW PIPES AT CENTER, COLD FLOW LABORATORY ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. CATCH BASIN, INFLOW PIPES AT CENTER, COLD FLOW LABORATORY AT LEFT, VIEW TOWARDS NORTHWEST. - Glenn L. Martin Company, Titan Missile Test Facilities, Catch Basin, Waterton Canyon Road & Colorado Highway 121, Lakewood, Jefferson County, CO

Severe aortic stenosis patients with preserved ejection fraction according to flow and gradient classification: Prevalence and outcomes.

PubMed

González Gómez, Ariana; Fernández-Golfín, Covadonga; Monteagudo, Juan Manuel; Izurieta, Carlos; Hinojar, Rocío; García, Ana; Casas, Eduardo; Jiménez-Nacher, José Julio; Moya, José Luis; Ruiz, Soledad; Zamorano, José Luis

2017-12-01

Clinicians often encounter patients with apparently discordant echocardiographic findings, severe aortic stenosis (SAS) defined by aortic valve area (AVA) despite a low mean gradient. A new classification according to flow state and pressure gradient has been proposed. We sought to assess the prevalence, characteristics and outcomes of patients with asymptomatic SAS with preserved left-ventricular ejection fraction (LVEF) according to flow and gradient. In total 442 patients with SAS (AVAi<0.6 cm2/m2) and LVEF ≥50% (mean age 80+11years, 54,5% female) were included. Patients were classified according to flow state (≥ or <35ml/m 2 ) and mean pressure gradient (≥ or <40mmHg): Low Flow/Low Gradient (LF/LG): 21.3%(n=94); Normal Flow/Low Gradient (NF/LG): 32.1%(n=142); Low Flow/High Gradient (LF/HG): 6.8%(n=30); Normal Flow/High Gradient (NF/HG): 39,8%(n=176). Mean follow-up time was 20.5months (SD=10.3). Primary combined endpoint was cardiovascular mortality and hospital admission for SAS related symptom, secondary endpoint was aortic valve replacement (AVR), comparing HG group to LF/LG group. During follow-up 17 (18%) of LF/LG patients and 21 (10.2%) of HG patients met the primary endpoint. A lower free of event survival (cardiovascular mortality and hospital admission) was observed in patients with LF/LG AS (Breslow, p=0.002). Significant differences were noted between groups with a lower AVR free survival in the LF/LG group compared to HG groups (Breslow, p=0.002). Our study confirms the high prevalence and worse prognosis of LF/LG SAS. Clinicians must be aware of this entity to ensure appropriate patient management. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

Intraoperative coronary grafts flow measurement using the TTFM flowmeter: results from a domestic sample.

PubMed

Succi, José Ernesto; Gerola, Luis Roberto; Succi, Guilherme de Menezes; Kim, Hyong Chun; Paredes, Jorge Edwin Morocho; Bufollo, Enio

2012-01-01

To evaluate intraoperative graft patency and identify grafts under risk of early occlusion. Fifty four patients were submitted to coronary artery bypass surgery and the graft flow was assessed by the Flowmeter (Medtronic Medistim), which utilizes the TTFM method. Three patients had left main disease and 48 had normal or mildly reduced left ventricular function. In hospital mortality was 3.7% (two patients), one for mesenteric thrombosis and one due to cardiogenic chock. Seventeen patients (34%) were submitted to off pump CABG. Arterial Graft flow measures ranged from 8 to 106 ml/min (average 31.14 ml/min), and venous grafts flow ranged from 9 to 149 ml/min (average 50.42 ml/min). Flowmeter use represents higher safety both for patients and surgeons. Even under legal aspects, the documentation provided by the device can avoid future questionings.

Label-free in vivo optical micro-angiography imaging of cerebral capillary blood flow within meninges and cortex in mice with the skull left intact

NASA Astrophysics Data System (ADS)

Jia, Yali; Wang, Ruikang K.

2011-03-01

Abnormal microcirculation within meninges is common in many neurological diseases. There is a need for an imaging method that is capable of visualizing functional meningeal microcirculations alone, preferably decoupled from the cortical blood flow. Optical microangiography (OMAG) is a recently developed label-free imaging method capable of producing 3D images of dynamic blood perfusion within micro-circulatory tissue beds at an imaging depth up to ~2 mm, with an unprecedented imaging sensitivity to the blood flow at ~4 μm/s. In this study, we demonstrate the utility of ultra-high sensitive OMAG in imaging the detailed blood flow distributions, at a capillary level resolution, within meninges and cortex in mice with the cranium left intact. The results indicate that OMAG can be a valuable tool for the study of meningeal circulations.

Nodal Cilia Dynamics and the Specification of the Left/Right Axis in Early Vertebrate Embryo Development

PubMed Central

Buceta, Javier; Ibañes, Marta; Rasskin-Gutman, Diego; Okada, Yasushi; Hirokawa, Nobutaka; Izpisúa-Belmonte, Juan Carlos

2005-01-01

Nodal cilia dynamics is a key factor for left/right axis determination in mouse embryos through the induction of a leftward fluid flow. So far it has not been clearly established how such dynamics is able to induce the asymmetric leftward flow within the node. Herein we propose that an asymmetric two-phase nonplanar beating cilia dynamics that involves the bending of the ciliar axoneme is responsible for the leftward fluid flow. We support our proposal with a host of hydrodynamic arguments, in silico experiments and in vivo video microscopy data in wild-type embryos and inv mutants. Our phenomenological modeling approach underscores how the asymmetry and speed of the flow depends on different relevant parameters. In addition, we discuss how the combination of internal and external mechanisms might cause the two-phase beating cilia dynamics. PMID:16040754

Initial in vitro testing of a paediatric continuous-flow total artificial heart.

PubMed

Fukamachi, Kiyotaka; Karimov, Jamshid H; Horvath, David J; Sunagawa, Gengo; Byram, Nicole A; Kuban, Barry D; Moazami, Nader

2018-06-01

Mechanical circulatory support has become standard therapy for adult patients with end-stage heart failure; however, in paediatric patients with congenital heart disease, the options for chronic mechanical circulatory support are limited to paracorporeal devices or off-label use of devices intended for implantation in adults. Congenital heart disease and cardiomyopathy often involve both the left and right ventricles; in such cases, heart transplantation, a biventricular assist device or a total artificial heart is needed to adequately sustain both pulmonary and systemic circulations. We aimed to evaluate the in vitro performance of the initial prototype of our paediatric continuous-flow total artificial heart. The paediatric continuous-flow total artificial heart pump was downsized from the adult continuous-flow total artificial heart configuration by a scale factor of 0.70 (1/3 of total volume) to enable implantation in infants. System performance of this prototype was evaluated using the continuous-flow total artificial heart mock loop set to mimic paediatric circulation. We generated maps of pump performance and atrial pressure differences over a wide range of systemic vascular resistance/pulmonary vascular resistance and pump speeds. Performance data indicated left pump flow range of 0.4-4.7 l/min at 100 mmHg delta pressure. The left/right atrial pressure difference was maintained within ±5 mmHg with systemic vascular resistance/pulmonary vascular resistance ratios between 1.4 and 35, with/without pump speed modulation, verifying expected passive self-regulation of atrial pressure balance. The paediatric continuous-flow total artificial heart prototype met design requirements for self-regulation and performance; in vivo pump performance studies are ongoing.

11. photographer unknown 3 September 1984 AERIAL VIEW OF BONNEVILLE ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

11. photographer unknown 3 September 1984 AERIAL VIEW OF BONNEVILLE PROJECT TAKEN AT 6000-FOOT ELEVATION. POWERHOUSE #1 AND NAVIGATION LOCK ARE IN UPPER/CENTER PART OF PHOTO, AND THE DAM/SPILLWAY IS IN LEFT/CENTER; THE SECOND POWERHOUSE IS PARTIALLY VISIBLE IN LOWER LEFT CORNER. COLUMBIA RIVER FLOWS FROM LEFT-TO-RIGHT. - Bonneville Project, Columbia River, 1 mile Northeast of Exit 40, off Interstate 84, Bonneville, Multnomah County, OR

23. VIEW OF 'MEZZANINE,' FIRST FLOOR, LOOKING NORTHEAST. AT LEFT ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

23. VIEW OF 'MEZZANINE,' FIRST FLOOR, LOOKING NORTHEAST. AT LEFT CENTER IS THE VERTICAL SHAFT FROM TURBINE BELOW. AT CENTER, SUSPENDED FROM THE CEILING, IS A SILVER CREEK FLOUR PACKER, PATENTED IN 1879. AT FAR LEFT, MOUNTED ON THE WALL, IS A GAUGE THAT FORMERLY MEASURED CANAL FLOW. Photographer: Jet T. Lowe, 1985 - Alexander's Grist Mill, Lock 37 on Ohio & Erie Canal, South of Cleveland, Valley View, Cuyahoga County, OH

Computational Simulations of Inferior Vena Cava (IVC) Filter Placement and Hemodynamics in Patient-Specific Geometries

NASA Astrophysics Data System (ADS)

Aycock, Kenneth; Sastry, Shankar; Kim, Jibum; Shontz, Suzanne; Campbell, Robert; Manning, Keefe; Lynch, Frank; Craven, Brent

2013-11-01

A computational methodology for simulating inferior vena cava (IVC) filter placement and IVC hemodynamics was developed and tested on two patient-specific IVC geometries: a left-sided IVC, and an IVC with a retroaortic left renal vein. Virtual IVC filter placement was performed with finite element analysis (FEA) using non-linear material models and contact modeling, yielding maximum vein displacements of approximately 10% of the IVC diameters. Blood flow was then simulated using computational fluid dynamics (CFD) with four cases for each patient IVC: 1) an IVC only, 2) an IVC with a placed filter, 3) an IVC with a placed filter and a model embolus, all at resting flow conditions, and 4) an IVC with a placed filter and a model embolus at exercise flow conditions. Significant hemodynamic differences were observed between the two patient IVCs, with the development of a right-sided jet (all cases) and a larger stagnation region (cases 3-4) in the left-sided IVC. These results support further investigation of the effects of IVC filter placement on a patient-specific basis.

EC97-44293-3

NASA Image and Video Library

1997-09-29

Four different versions of the F-16 were used by Dryden in the 1990s. On the left and right sides are two F-16XLs. On the left is the F-16XL #2 (NASA 848), which is the two-seat version, used for advanced laminar flow studies until late 1996. On the right is the single-seat F-16XL #1 (NASA 849), used for laminar flow research and sonic boom research. (Laminar flow refers to smooth airflow over a wing, which increases lift and reduces drag compared to turbulent airflow). Between them at center left is an F-16A (NASA 816), the only civilian operated F-16. Next to it at center right is the U.S. Air Force Advance Fighter Technology Integration (AFTI) F-16, a program to test new sensor and control technologies for future fighter aircraft. Both F-16XLs are in storage at Dryden. The F-16A was never flown at Dryden, and was parked by the entrance to the center. The AFTI F-16 is in the Air Force Museum.

EC97-44293-1

NASA Image and Video Library

1997-09-29

Four different versions of the F-16 were used by Dryden in the 1990s. On the left and right sides are two F-16XLs. On the left is the F-16XL #2 (NASA 848), which is the two-seat version, used for advanced laminar flow studies until late 1996. On the right is the single-seat F-16XL #1 (NASA 849), used for laminar flow research and sonic boom research. (Laminar flow refers to smooth airflow over a wing, which increases lift and reduces drag compared to turbulent airflow). Between them at center left is an F-16A (NASA 816), the only civilian operated F-16. Next to it at center right is the U.S. Air Force Advance Fighter Technology Integration (AFTI) F-16, a program to test new sensor and control technologies for future fighter aircraft. Both F-16XLs are in storage at Dryden. The F-16A was never flown at Dryden, and was parked by the entrance to the center. The AFTI F-16 is in the Air Force Museum.

A Computational Chemo-Fluidic Modeling for the Investigation of Patient-Specific Left Ventricle Thrombogenesis

NASA Astrophysics Data System (ADS)

Mittal, Rajat; Seo, Jung Hee; Abd, Thura; George, Richard T.

2015-11-01

Patients recovering from myocardial infarction (MI) are considered at high-risk for cardioembolic stroke due to the formation of left ventricle thrombus (LVT). The formation of LVT is the result of a complex interplay between the fluid dynamics inside the ventricle and the chemistry of coagulation, and the role of LV flow pattern on the thrombogenesis was not well understood. The previous computational study performed with the model ventricles suggested that the local flow residence time is the key variable governing the accumulation of coagulation factors. In the present study, a coupled, chemo-fluidic computational modeling is applied to the patient-specific cases of infracted ventricles to investigate the interaction between the LV hemodynamics and thrombogensis. In collaboration with the Johns Hopkins hospital, patient-specific LV models are constructed using the multi-modality medical imaging data. Blood flow in the left ventricle is simulated by solving the incompressible Navier-Stokes equations and the biochemical reactions for the thrombus formation are modeled with convection-diffusion-reaction equations. The formation and deposition of key coagulation chemical factors are then correlated with the hemodynamic flow metrics to explore the biophysics underlying LVT risk. Supported by the Johns Hopkins Medicine Discovery Fund and NSF Grant: CBET-1511200, Computational resource by XSEDE NSF grant TG-CTS100002.

[Quantitative Measurements on the Blood Flow Fields of Left Atrial Appendage using Vector Flow Mapping in Patients with Nonvalvular Atrial Fibrillation].

PubMed

Cai, Yu-Yan; Wei, Xin; Zhang, Xiao-Ling; Liu, Gu-Yue; Li, Xi; Tang, Hong

2018-01-01

To quantify the hemodynamic characteristics of patients with nonvalvular atrial fibrillation. Twenty patients with paroxysmal atrial fibrillation and 15 patients with persistent atrial fibrillation enrolled in this study,while 12 patients with sinus rhythms served as controls. The hemodynamic characteristics of the patients in left atrial appendage were measured by transesophageal echocardiography (TEE) and vector flow mapping (VFM) using indicators such as vectors,vortex and energy loss (EL). ① Significant differences appeared between the patients with atrial fibrillation and the controls in heart rate,size of left atrium,size of left atrial appendage (LAA),and velocities of LAA filling and emptying. ② Regular vectors in LAA in early systole and late diastole were found in the patients with paroxysmal atrial fibrillation and the controls; whereas,irregular vectors with direction alternating were visualized in the whole cardiac cycle in the patients with persistent atrial fibrillation. ③ Small vortexes were observed at the opening of the left atrial appendage in late diastole in the patients with paroxysmal atrial fibrillation and the controls. ④ Peak EL values occurred in early systole and late diastole in the patients with paroxysmal atrial fibrillation and the controls. But the patients with persistent atrial fibrillation had increased EL values over the whole cardiac cycle. VFM can visualize and quantify the hemodynamics of LAA in patients with different heart rhythms. It may provide a new method for assessing atrial fibrillation. CopyrightCopyright© by Editorial Board of Journal of Sichuan University (Medical Science Edition).

[Hemodynamic study of the patient with hemorrhagic portal hypertension: importance of the left renal vein in patients with a distal splenorenal shunt (Warren)].

PubMed

Orozco, Héctor; Tielve, Manuel; Ramos, Guillermo; Mercado, Miguel Angel

2006-01-01

There is no information in the literature about surgical outcome of the distal splenorenal shunt (Warren shunt) in those patients with anomalous flow in the left renal vein to the inferior vena cava. The purpose of this manuscript was to evaluate the incidence of thrombosis in the Warren shunt in those patients with anomalous flow in the left renal vein to the inferior vena cava. We performed a prospective, descriptive and longitudinal study in those patients who performed a surgical procedure to the treatment of hemorrhagic portal hypertension in a tertiary referral center in Mexico City during a one year period (2002-2003). Before the surgical procedure an arterial and venous angiographic study was done including celiac axis, superior mesenteric artery and splenic artery. The patients were scheduled in the outpatient office the first, third, sixth month and the year after the surgical procedure. We looked in them for gastrointestinal bleeding secondary to portal hypertension. In those patients with Warren shunt an angiographic study was done during the first month after the surgical procedure. Twenty eight patients were included, 17 of them women (60.7%). Median patient age was 48 years old. In 20 patients a Warren shunt were done and in eigth patients a devascularization operation were done. The anomalous flow of the left renal vein was identified in nine patients (28.7%). In seven of them a Warren shunt were done and in two of them a devascularization operation were done. We didn't find gastrointestinal bleeding or thrombosis of the Warren shunt in any of these patients. In those cases of patients with anomalous flow in the left renal vein a Warren shunt can be performed. In this study we didn't find thrombosis of the shunt or gastrointestinal bleeding. In this way a surgical decompression of the portal system can be done preventing bleeding episodes.

The effect of transient balloon occlusion of the mitral valve on left atrial appendage blood flow velocity and spontaneous echo contrast.

PubMed

Wang, J; Chung Ann Choo, D; Zhang, X; Yang, Q; Xian, T; Lu, D; Jiang, S

2000-07-01

Spontaneous echo contrast (SEC) is a phenomenon that is commonly seen in areas of blood stasis. It is a slowly moving, cloud-like swirling pattern of "smoke" or increased echogenicity recorded on echocardiography. SEC is commonly seen in the left atrium of patients with mitral stenosis or atrial fibrillation. The presence of SEC has been shown to be a marker of increased thromboembolic risk. By using transesophageal echocardiography during percutaneous balloon mitral valvotomy (PBMV), the study investigated the relationship between SEC and varying left atrial appendage (LAA) blood flow velocity in the human heart. Thirty-five patients with rheumatic mitral stenosis underwent percutaneous balloon mitral valvotomy with intraoperative transesophageal echocardiography monitoring. We alternatively measured LAA velocities and observed the left atrium for various grades of SEC (0 = none to 4 = severe) before and after each balloon inflation. Left atrial appendage maximal ejection velocity was reduced from 35 +/- 14 to 6 +/- 2 mm/s at peak balloon inflation and increased to 40 +/- 16 mm/s after balloon deflation. In comparison with the values before balloon inflation and after balloon deflation, LAA velocities were significantly lower (p < 0.001). New or increased SEC grade was observed during 54 of 61 (88%) inflations and unchanged in 7 (12%) inflations at peak balloon inflation. Spontaneous echo contrast became lower in grade after 55 balloon deflations (90%), completely disappeared after 18 deflations (30%), and remained unchanged after 6 deflations (10%). The mean time to achieve maximal SEC grade (2.5 +/- 1.2 s) coincided with the mean time to trough LAA velocities (2.3 +/- 1.1 s) after balloon inflation. Upon deflation, the mean time to lowest SEC grade (2.9 +/- 1.8 s) coincided with mean time to achieve maximal LAA velocities (2.7 +/- 1.6 s). During balloon inflation, the severity of SEC was enhanced with corresponding reduction in LAA flow velocity. Upon balloon deflation, SEC lightens or disappears with increase in LAA flow velocity.

Evaluation of a new 3-dimensional color Doppler flow method to quantify flow across the mitral valve and in the left ventricular outflow tract: an in vitro study.

PubMed

Kimura, Sumito; Streiff, Cole; Zhu, Meihua; Shimada, Eriko; Datta, Saurabh; Ashraf, Muhammad; Sahn, David J

2014-02-01

The aim of this study was to assess the accuracy, feasibility, and reproducibility of determining stroke volume from a novel 3-dimensional (3D) color Doppler flow quantification method for mitral valve (MV) inflow and left ventricular outflow tract (LVOT) outflow at different stroke volumes when compared with the actual flow rate in a pumped porcine cardiac model. Thirteen freshly harvested pig hearts were studied in a water tank. We inserted a latex balloon into each left ventricle from the MV annulus to the LVOT, which were passively pumped at different stroke volumes (30-80 mL) using a calibrated piston pump at increments of 10 mL. Four-dimensional flow volumes were obtained without electrocardiographic gating. The digital imaging data were analyzed offline using prototype software. Two hemispheric flow-sampling planes for color Doppler velocity measurements were placed at the MV annulus and LVOT. The software computed the flow volumes at the MV annulus and LVOT within the user-defined volume and cardiac cycle. This novel 3D Doppler flow quantification method detected incremental increases in MV inflow and LVOT outflow in close agreement with pumped stroke volumes (MV inflow, r = 0.96; LVOT outflow, r = 0.96; P < .01). Bland-Altman analysis demonstrated overestimation of both (MV inflow, 5.42 mL; LVOT outflow, 4.46 mL) with 95% of points within 95% limits of agreement. Interobserver variability values showed good agreement for all stroke volumes at both the MV annulus and LVOT. This study has shown that the 3D color Doppler flow quantification method we used is able to compute stroke volumes accurately at the MV annulus and LVOT in the same cardiac cycle without electrocardiographic gating. This method may be valuable for assessment of cardiac output in clinical studies.

Atrial supply-demand balance in healthy adult pigs: coronary blood flow, oxygen extraction, and lactate production during acute atrial fibrillation.

PubMed

van Bragt, Kelly A; Nasrallah, Hussein M; Kuiper, Marion; Luiken, Joost J; Schotten, Ulrich; Verheule, Sander

2014-01-01

Little is known about how atrial oxygen supply responds to increased demand, and under which conditions it falls short (supply-demand mismatch). Here, we have investigated the vasodilator response, oxygen extraction, and lactate production of the left atrium (LA) and left ventricle (LV) in response to atrial pacing and atrial fibrillation (AF). Series A (n = 9 Dutch landrace pigs) was instrumented to measure LA and LV vascular conductance in branches of the circumflex artery. Coronary conductance reserve (CCR) was calculated as the ratio between conductance during adenosine infusion and baseline. Series B (n = 7) was instrumented with sampling catheters in LA and LV veins for determination of blood gases and lactate levels. LA CCR (1.76 ± 0.14) was significantly lower than LV CCR (3.16 ± 0.27, P = 0.002). However, basal oxygen extraction was lower in LA (27 ± 3%) than that in the LV (58 ± 6%, P = 0.0006), indicating a larger extraction reserve in the LA than that in the LV (4.68 ± 0.84 vs. 1.88 ± 0.26, P = 0.01). Atrial pacing caused an increase in LA conductance (Series A) and oxygen extraction (Series B). AF increased LA vascular conductance to 177 ± 14% at 1 min, 168 ± 14 at 5 min, and 164 ± 31% at 10 min of AF (P < 0.05 vs. baseline). Atrial oxygen extraction also increased from 26 ± 3% at baseline to 63 ± 5% (P < 0.01) at 5 min and 60 ± 11% (P < 0.01) at 10 min of AF. Arterio-venous lactate difference increased significantly (P = 0.02) during AF. In healthy pigs, the LA has a lower CCR, but a higher extraction reserve compared with the LV. Although both reserves were recruited during AF, atrial lactate production increased significantly.

The value of assessing pulmonary venous flow velocity for predicting severity of mitral regurgitation: A quantitative assessment integrating left ventricular function

NASA Technical Reports Server (NTRS)

Pu, M.; Griffin, B. P.; Vandervoort, P. M.; Stewart, W. J.; Fan, X.; Cosgrove, D. M.; Thomas, J. D.

1999-01-01

Although alteration in pulmonary venous flow has been reported to relate to mitral regurgitant severity, it is also known to vary with left ventricular (LV) systolic and diastolic dysfunction. There are few data relating pulmonary venous flow to quantitative indexes of mitral regurgitation (MR). The object of this study was to assess quantitatively the accuracy of pulmonary venous flow for predicting MR severity by using transesophageal echocardiographic measurement in patients with variable LV dysfunction. This study consisted of 73 patients undergoing heart surgery with mild to severe MR. Regurgitant orifice area (ROA), regurgitant stroke volume (RSV), and regurgitant fraction (RF) were obtained by quantitative transesophageal echocardiography and proximal isovelocity surface area. Both left and right upper pulmonary venous flow velocities were recorded and their patterns classified by the ratio of systolic to diastolic velocity: normal (>/=1), blunted (<1), and systolic reversal (<0). Twenty-three percent of patients had discordant patterns between the left and right veins. When the most abnormal patterns either in the left or right vein were used for analysis, the ratio of peak systolic to diastolic flow velocity was negatively correlated with ROA (r = -0.74, P <.001), RSV (r = -0.70, P <.001), and RF (r = -0.66, P <.001) calculated by the Doppler thermodilution method; values were r = -0.70, r = -0.67, and r = -0.57, respectively (all P <.001), for indexes calculated by the proximal isovelocity surface area method. The sensitivity, specificity, and predictive values of the reversed pulmonary venous flow pattern for detecting a large ROA (>0.3 cm(2)) were 69%, 98%, and 97%, respectively. The sensitivity, specificity, and predictive values of the normal pulmonary venous flow pattern for detecting a small ROA (<0.3 cm(2)) were 60%, 96%, and 94%, respectively. However, the blunted pattern had low sensitivity (22%), specificity (61%), and predictive values (30%) for detecting ROA of greater than 0.3 cm(2) with significant overlap with the reversed and normal patterns. Among patients with the blunted pattern, the correlation between the systolic to diastolic velocity ratio was worse in those with LV dysfunction (ejection fraction <50%, r = 0.23, P >.05) than in those with normal LV function (r = -0.57, P <.05). Stepwise linear regression analysis showed that the peak systolic to diastolic velocity ratio was independently correlated with RF (P <.001) and effective stroke volume (P <.01), with a multiple correlation coefficient of 0.71 (P <.001). In conclusion, reversed pulmonary venous flow in systole is a highly specific and reliable marker of moderately severe or severe MR with an ROA greater than 0.3 cm(2), whereas the normal pattern accurately predicts mild to moderate MR. Blunted pulmonary venous flow can be seen in all grades of MR with low predictive value for severity of MR, especially in the presence of LV dysfunction. The blunted pulmonary venous flow pattern must therefore be interpreted cautiously in clinical practice as a marker for severity of MR.

Influence of the Valsalva maneuver on cardiac hemodynamics and right to left shunt in patients with patent foramen ovale

NASA Astrophysics Data System (ADS)

Zhao, Enfa; Zhang, Yafei; Kang, Chunmiao; Niu, Hua; Zhao, Jing; Sun, Lei; Liu, Baomin

2017-03-01

The purpose of this study was to investigate the influence of the Valsalva maneuver (VM) on cardiac hemodynamics in patients with patent foramen ovale (PFO). Sixty-five patients who were highly suspected to have PFO were included. The changes in E, A, E/A ratio of mitral valve blood flow, E, A, E/A ratio of tricuspid valve blood flow, left ventricular end-diastolic volume, area and right atrial area during the resting state and the strain phase of the Valsalva maneuver were observed by transthoracic echocardiography (TTE). Statistical analyses were performed using SPSS Version18.0. Compared to the resting state, mitral valve diastolic velocity E and A peaks at the strain phase of the Valsalva maneuver significantly decreased (P < 0.05), left ventricular end diastolic volume(LVEDV) and area(LVEDA) decreased significantly (P < 0.05), while E/A ratio of mitral valve, tricuspid valve systolic velocity E and A peaks and E/A ratio remained unchanged (P > 0.05). PFO hemodynamic changes mainly occurred in the left ventricle when the Valsalva maneuver was performed. The Valsalva maneuver increased pressure in the chest, then pulmonary venous return was impeded, which resulted in left ventricular limited filling, and E and A peaks decreased. The pressure of the left ventricle and atrium was lower than that of the right side, which resulted in right-to-left shunt (RLS) through PFO.

Transient left septal and anterior fascicular block associated with type 1 electrocardiographic Brugada pattern.

PubMed

Pérez-Riera, Andrés Ricardo; Barbosa-Barros, Raimundo; Penachini da Costa de Rezende Barbosa, Marianne; Daminello-Raimundo, Rodrigo; de Abreu, Luiz Carlos

The left septal fascicular block (LSFB) or blockage of the middle fibers of the left bundle branch is probably caused mainly by - in the developed world - the proximal obstruction of the left anterior descending artery (LAD) before its first anterior septal perforator branch (S 1 ). The association of transient LSFB and left anterior fascicular block (LAFB) - left bifascicular block - and the electrocardiographic type 1 Brugada pattern (BrP) has not been described in the literature yet. Copyright © 2017 Elsevier Inc. All rights reserved.

Modeling and control of a brushless DC axial flow ventricular assist device.

PubMed

Giridharan, Guruprasad A; Skliar, Mikhail; Olsen, Donald B; Pantalos, George M

2002-01-01

This article presents an integrated model of the human circulatory system that incorporates circulatory support by a brushless DC axial flow ventricular assist device (VAD), and a feedback VAD controller designed to maintain physiologically sufficient perfusion. The developed integrated model combines a network type model of the circulatory system with a nonlinear dynamic model of the brushless DC pump We show that maintaining a reference differential pressure between the left ventricle and aorta leads to adequate perfusion for different pathologic cases, ranging from normal heart to left heart asystole, and widely varying physical activity scenarios from rest to exercise.

Left frontal hub connectivity delays cognitive impairment in autosomal-dominant and sporadic Alzheimer's disease.

PubMed

Franzmeier, Nicolai; Düzel, Emrah; Jessen, Frank; Buerger, Katharina; Levin, Johannes; Duering, Marco; Dichgans, Martin; Haass, Christian; Suárez-Calvet, Marc; Fagan, Anne M; Paumier, Katrina; Benzinger, Tammie; Masters, Colin L; Morris, John C; Perneczky, Robert; Janowitz, Daniel; Catak, Cihan; Wolfsgruber, Steffen; Wagner, Michael; Teipel, Stefan; Kilimann, Ingo; Ramirez, Alfredo; Rossor, Martin; Jucker, Mathias; Chhatwal, Jasmeer; Spottke, Annika; Boecker, Henning; Brosseron, Frederic; Falkai, Peter; Fliessbach, Klaus; Heneka, Michael T; Laske, Christoph; Nestor, Peter; Peters, Oliver; Fuentes, Manuel; Menne, Felix; Priller, Josef; Spruth, Eike J; Franke, Christiana; Schneider, Anja; Kofler, Barbara; Westerteicher, Christine; Speck, Oliver; Wiltfang, Jens; Bartels, Claudia; Araque Caballero, Miguel Ángel; Metzger, Coraline; Bittner, Daniel; Weiner, Michael; Lee, Jae-Hong; Salloway, Stephen; Danek, Adrian; Goate, Alison; Schofield, Peter R; Bateman, Randall J; Ewers, Michael

2018-04-01

Patients with Alzheimer's disease vary in their ability to sustain cognitive abilities in the presence of brain pathology. A major open question is which brain mechanisms may support higher reserve capacity, i.e. relatively high cognitive performance at a given level of Alzheimer's pathology. Higher functional MRI-assessed functional connectivity of a hub in the left frontal cortex is a core candidate brain mechanism underlying reserve as it is associated with education (i.e. a protective factor often associated with higher reserve) and attenuated cognitive impairment in prodromal Alzheimer's disease. However, no study has yet assessed whether such hub connectivity of the left frontal cortex supports reserve throughout the evolution of pathological brain changes in Alzheimer's disease, including the presymptomatic stage when cognitive decline is subtle. To address this research gap, we obtained cross-sectional resting state functional MRI in 74 participants with autosomal dominant Alzheimer's disease, 55 controls from the Dominantly Inherited Alzheimer's Network and 75 amyloid-positive elderly participants, as well as 41 amyloid-negative cognitively normal elderly subjects from the German Center of Neurodegenerative Diseases multicentre study on biomarkers in sporadic Alzheimer's disease. For each participant, global left frontal cortex connectivity was computed as the average resting state functional connectivity between the left frontal cortex (seed) and each voxel in the grey matter. As a marker of disease stage, we applied estimated years from symptom onset in autosomal dominantly inherited Alzheimer's disease and cerebrospinal fluid tau levels in sporadic Alzheimer's disease cases. In both autosomal dominant and sporadic Alzheimer's disease patients, higher levels of left frontal cortex connectivity were correlated with greater education. For autosomal dominant Alzheimer's disease, a significant left frontal cortex connectivity × estimated years of onset interaction was found, indicating slower decline of memory and global cognition at higher levels of connectivity. Similarly, in sporadic amyloid-positive elderly subjects, the effect of tau on cognition was attenuated at higher levels of left frontal cortex connectivity. Polynomial regression analysis showed that the trajectory of cognitive decline was shifted towards a later stage of Alzheimer's disease in patients with higher levels of left frontal cortex connectivity. Together, our findings suggest that higher resilience against the development of cognitive impairment throughout the early stages of Alzheimer's disease is at least partially attributable to higher left frontal cortex-hub connectivity.

Zephyria Channel System

NASA Technical Reports Server (NTRS)

2004-01-01

10 September 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a portion of an outflow channel system located in the Zephyria region, south of Cerberus, from which vast quantities of rough-surfaced material flowed. The channel system has no name and was not known prior to the MGS mission. The material that flowed through this system may have been extremely fluid lava, or it may have been water-rich mud. Research by members of the Mars science community regarding the nature and origin of flow materials in the Cerberus, Zephyria, and Marte Vallis regions of Mars is on-going. This image is located near 4.6oN, 204.1oW. The image covers an area approximately 3 km (1.9 mi) across and is illuminated by sunlight from the left/lower left.

Kinematic, Dynamic, and Energy Characteristics of Diastolic Flow in the Left Ventricle

PubMed Central

Khalafvand, Seyed Saeid; Hung, Tin-Kan; Ng, Eddie Yin-Kwee; Zhong, Liang

2015-01-01

Blood flow characteristics in the normal left ventricle are studied by using the magnetic resonance imaging, the Navier-Stokes equations, and the work-energy equation. Vortices produced during the mitral valve opening and closing are modeled in a two-dimensional analysis and correlated with temporal variations of the Reynolds number and pressure drop. Low shear stress and net pressures on the mitral valve are obtained for flow acceleration and deceleration. Bernoulli energy flux delivered to blood from ventricular dilation is practically balanced by the energy influx and the rate change of kinetic energy in the ventricle. The rates of work done by shear and energy dissipation are small. The dynamic and energy characteristics of the 2D results are comparable to those of a 3D model. PMID:26417381

Left isomerism syndrome with total anomalous systemic connection.

PubMed

Vo, Anh Tuan; Cao, Khang Dang; Le, Khoi Minh; Nguyen, Dinh Hoang

2017-01-01

We present a case of left isomerism with total anomalous systemic venous connection where the inferior vena cava was absent and all other systemic veins connected abnormally to the left atrium. The right atrium was hypoplastic with an intact atrial septum. Blood flow to the lungs was through a large ventricular septal defect. The diagnosis was made with echocardiography, angiography, and computed tomography. Complete repair was performed successfully, and the 7-year-old patient had an uneventful recovery.

Acquired heart block: a possible complication of patent ductus arteriosus in a preterm infant.

PubMed

Grasser, Monika; Döhlemann, Christoph; Mittal, Rashmi; Till, Holger; Dietz, Hans-Georg; Münch, Georg; Holzinger, Andreas

2008-01-01

A large patent ductus arteriosus (PDA) is a frequently encountered clinical problem in extremely low birth weight (ELBW) infants. It leads to an increased pulmonary blood flow and in a decreased or reversed diastolic flow in the systemic circulation, resulting in complications. Here we report a possible complication of PDA not previously published. On day 8 of life, a male ELBW infant (birth weight 650 g) born at a gestational age of 23 weeks and 3 days developed an atrioventricular block (AV block). The heart rate dropped from 168/min to 90/min, and the ECG showed a Wenckebach second-degree AV block and intraventricular conduction disturbances. Echocardiography demonstrated a PDA with a large left-to-right shunt and large left atrium and left ventricle with high contractility. Within several minutes after surgical closure of the PDA, the heart rate increased, and after 30 min the AV block had improved to a 1:1 conduction ratio. Echocardiography after 2 h revealed a significant decrease of the left ventricular and atrial dimensions. Within 12 h, the AV block completely reversed together with the intraventricular conduction disturbances. We suggest that PDA with a large left-to-right shunt and left ventricular volume overload may lead to an AV block in an ELBW infant. Surgical closure of the PDA may be indicated. (c) 2007 S. Karger AG, Basel.

The value of fractional and coronary flow reserve in predicting myocardial recovery in patients with previous myocardial infarction.

PubMed

Beleslin, Branko; Ostojic, Miodrag; Djordjevic-Dikic, Ana; Vukcevic, Vladan; Stojkovic, Sinisa; Nedeljkovic, Milan; Stankovic, Goran; Orlic, Dejan; Milic, Natasa; Stepanovic, Jelena; Giga, Vojislav; Saponjski, Jovica

2008-11-01

The aim of the study was to evaluate the relation between fractional flow reserve (FFR) and simultaneously evaluated coronary flow reserve by thermodilution (CFRthermo), with the improvement of left ventricular (LV) function in patients with previous myocardial infarction (MI) undergoing percutaneous coronary intervention (PCI). Study population consisted of 46 patients (mean age 53 +/- 7 years; 36 male) with previous MI and significant coronary stenosis undergoing PCI of infarct-related coronary artery. In all patients, we evaluated FFR and CFRthermo by single pressure/thermo wire during maximal hyperaemia before and immediately after PCI. We performed echocardiographic assessment of LV ejection fraction before and 6 months after PCI. Dobutamine stress echocardiography test was also performed before PCI. LV functional improvement was observed in 33/46 (72%) of patients. In patients with LV functional recovery in comparison with patients with no recovery, there was a significant difference in FFR before PCI (0.56 +/- 0.14 vs. 0.70 +/- 0.07, P < 0.001), improvement of FFR (0.35 +/- 0.14 vs. 0.21 +/- 0.07, P < 0.001), improvement of CFRthermo (1.3 +/- 0.6 vs. 0.5 +/- 0.3, P < 0.001), and CFRthermo after PCI (2.6 +/- 0.7 vs. 2.0 +/- 0.4, P < 0.001). When only parameters evaluated before PCI were taken into account, FFR before angioplasty (P = 0.001) and dobutamine-assessed viability (P = 0.006) were the most significant multivariate predictors of myocardial recovery. When all significant univariate parameters were evaluated, the most significant independent predictors for improvement in myocardial function were the improvement of CFRthermo during angioplasty (P < 0.001) and FFR before angioplasty (P = 0.002). Simultaneous evaluation of FFR and CFRthermo provide significant complementary data on the improvement in myocardial function in patients with previous MI. However, the evaluation of FFR before angioplasty identifies viable myocardium that may recover following revascularization and may be used as an alternative to non-invasive testing.

Septum primum atrial septal defect in an infant with hypoplastic left heart syndrome.

PubMed

Loar, Robert W; Burkhart, Harold M; Taggart, Nathaniel W

2014-08-01

Hypoplastic left heart syndrome (HLHS) is a form of congenital heart disease characterized by severe underdevelopment of the left heart, leading to inadequate systemic blood flow. Several different atrial septal morphologies are observed in HLHS, most commonly a secundum atrial septal defect, patent foramen ovale, intact septum, and leftward displacement of the superior attachment of the septum primum. It has been postulated that atrial septal development is associated with the development of the left heart. We present a case of a newborn infant with HLHS and the unusual finding of a primum ASD.

Phosphatidylserine-exposing blood cells and microparticles induce procoagulant activity in non-valvular atrial fibrillation.

PubMed

Wang, Lixiu; Bi, Yayan; Yu, Muxin; Li, Tao; Tong, Dongxia; Yang, Xiaoyan; Zhang, Cong; Guo, Li; Wang, Chunxu; Kou, Yan; Dong, Zengxiang; Novakovic, Valerie A; Tian, Ye; Kou, Junjie; Shammas, Masood A; Shi, Jialan

2018-05-01

The definitive role of phosphatidylserine (PS) in the prothrombotic state of non-valvular atrial fibrillation (NVAF) remains unclear. Our objectives were to study the PS exposure on blood cells and microparticles (MPs) in NVAF, and evaluate their procoagulant activity (PCA). NVAF patients without (n = 60) and with left atrial thrombi (n = 18) and controls (n = 36) were included in our study. Exposed PS was analyzed with flow cytometry and confocal microscopy. PCA was evaluated using clotting time, factor Xa (FXa), thrombin and fibrin formation. PS + blood cells and MPs were significantly higher in NVAF patients without and with left atrial thrombi (both P < 0.01) than in controls. Patients with left atrial thrombi showed increased PS + platelets, neutrophils, erythrocytes and MPs compared with patients without thrombi (all P < 0.05). Moreover, in patients with left atrial thrombi, MPs primarily originated from platelets (56.1%) followed by leukocytes (21.9%, including MPs from neutrophils, monocytes and lymphocytes), erythrocytes (12.2%) and endothelial cells (8.9%). Additionally, PS + blood cells and MPs contributed to markedly shortened coagulation time and dramatically increased FXa/thrombin/fibrin (all P < 0.001) generation in both NVAF groups. Furthermore, blockade of exposed PS on blood cells and MPs with lactadherin inhibited PCA by approximately 80%. Lastly, we found that the amount of PS + platelets and MPs was positively correlated with thrombus diameter (all p < 0.005). Our results suggest that exposed PS on blood cells and MPs play a procoagulant role in NVAF patients. Blockade of PS prior to thrombus formation might be a novel therapeutic approach in these patients. Copyright © 2018 Elsevier B.V. All rights reserved.

Significance of left ventricular diastolic function on outcomes after surgical ventricular restoration.

PubMed

Marui, Akira; Nishina, Takeshi; Saji, Yoshiaki; Yamazaki, Kazuhiro; Shimamoto, Takeshi; Ikeda, Tadashi; Sakata, Ryuzo

2010-05-01

Surgical ventricular restoration (SVR) has been introduced to restore the dilated left ventricular (LV) chamber and improve LV systolic function; however, SVR has also been reported to detrimentally affect LV diastolic properties. We sought to investigate the impact of preoperative LV diastolic function on outcomes after SVR in patients with heart failure. Sixty-seven patients (60 +/- 14 years) with LV systolic dysfunction (LV ejection fraction, 0.27 +/- 0.10) underwent SVR. They were evaluated by echocardiography preoperatively, and early (

Identification of general risk-management countermeasures for unsafe driving actions. Volume 3, A definitional study of speeding, following too closely, and driving left of center

DOT National Transportation Integrated Search

1981-02-01

The report develops a set of operational definitions for three unsafe driving actions (UDAs): speeding, following too closely, and driving left of center. The definitions flow from a methodological development and from an analysis of the literature a...

Investigation of Abnormal Left Temporal Functioning in Dyslexia through rCBF, Auditory Evoked Potentials, and Positron Emission Tomography.

ERIC Educational Resources Information Center

Wood, Frank; And Others

1991-01-01

Investigates the proposed left hemisphere dysfunction in dyslexia by reviewing four studies using regional cerebral blood flow (RCBF) and combined auditory evoked responses with positron emission tomography. Emphasizes methodological issues. Finds that dyslexics showed a positive correlation between Heschl's gyrus activation and phonemic…

70. VIEW OF UNIT 2 THROUGH ACCESS DOOR, LOOKING DOWN ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

70. VIEW OF UNIT 2 THROUGH ACCESS DOOR, LOOKING DOWN AT MAIN SHAFT. NOTE WELDER'S SIGNATURE IN SHADOWS IN UPPER LEFT CORNER AND PHOTOGRAPHER'S STROBE POWER CABLE IN LOWER RIGHT CORNER. ORIENTATION OF CAMERA IS FACING LEFT BANK, PERPENDICULAR TO RIVER FLOW - Swan Falls Dam, Snake River, Kuna, Ada County, ID

Octreotide for left ventricular assist device-related gastrointestinal hemorrhage: can we stop the bleeding?

PubMed

Rennyson, Stephen L; Shah, Keyur B; Tang, Daniel G; Kasirajan, Vigneshwar; Pedram, Sammy; Cahoon, William; Malhotra, Rajiv

2013-01-01

Left ventricular support devices (LVADs) are associated with a propensity toward gastrointestinal bleeding. A postulated mechanism is related to gastrointestinal arteriovenous malformations secondary to nonpulsatile flow. We describe a case of LVAD-related, gastrointestinal bleeding successfully treated with a combination of subcutaneous and intramuscular depot formulations of octreotide.

[Influence of detomidine on echocardiographic function parameters and cardiac hemodynamics in horses with and without heart murmur].

PubMed

Gehlen, H; Kroker, K; Deegen, E; Stadler, P

2004-03-01

30 warmblood horses were examined before and after sedation with 20 micrograms/kg BW detomidine, to determine changes of cardiac function parameters, using B-mode, M-mode and Doppler echocardiography. 15 horses showed a heart murmur, but no clinical signs of cardiac heart failure, 15 horses had neither a heart murmur nor other signs of cardiac disease. After sedation with detomidine we could recognise a significant increase of end-diastolic left atrium diameter, an increase of end-systolic left ventricular diameter and aortic root diameter. The end-systolic thickness of papillary muscle and interventricular septum showed a decrease. Fractional shortening and amplitude of left ventricular wall motion was decreased after sedation. The mitral valve echogram revealed a presystolic valve closure and an inflection in the Ac slope (B-notch) in xy horses before sedation. Both increased after sedation with detomidine. Doppler echocardiography showed a decrease of blood flow velocity and velocity time integral (VTI) in the left and right ventricular outflow tract after sedation. Regurgitant flow signals were intensified following sedation in xy horses, especially at the mitral valve.

Mechanism of reduction of mitral regurgitation with vasodilator therapy.

PubMed

Yoran, C; Yellin, E L; Becker, R M; Gabbay, S; Frater, R W; Sonnenblick, E H

1979-04-01

Acute mitral regurgitation was produced in six open chest dogs by excising a portion of the anterior valve leaflet. Electromagnetic flow probes were placed in the left atrium around the mitral anulus and in the ascending aorta to determine phasic left ventricular filling volume, regurgitant volume and stroke volume. The systolic pressure gradient was calculated from simultaneously measured high fidelity left atrial and left ventricular pressures. The effective mitral regurgitant orifice area was calculated from Gorlin's hydraulic equation. Infusion of nitroprusside resulted in a significant reduction in mitral regurgitation. No significant change occurred in the systolic pressure gradient between the left ventricle and the left atrium because both peak left ventricular pressure and left atrial pressure were reduced. The reduction of mitral regurgitation was largely due to reduction in the size of the mitral regurgitant orifice. Reduction of ventricular volume rather than the traditional concept of reduction of impedance of left ventricular ejection may explain the effects of vasodilators in reducing mitral regurgitation.

Implantable Cardioverter-Defibrillators in Patients With a Continuous-Flow Left Ventricular Assist Device: An Analysis of the INTERMACS Registry.

PubMed

Clerkin, Kevin J; Topkara, Veli K; Demmer, Ryan T; Dizon, Jose M; Yuzefpolskaya, Melana; Fried, Justin A; Mai, Xingchen; Mancini, Donna M; Takeda, Koji; Takayama, Hiroo; Naka, Yoshifumi; Colombo, Paolo C; Garan, A Reshad

2017-12-01

This study sought to determine if the presence of implantable cardioverter-defibrillators (ICD) provided a mortality benefit during continuous-flow left ventricular assist device (LVAD) support. An ICD decreases mortality in selected patients with advanced heart failure and have been associated with reduced mortality in patients with pulsatile LVAD. However, it is unclear whether that benefit extends to patients with a contemporary continuous-flow LVAD. Propensity score matching was used to generate a cohort of patients with similar baseline characteristics. The primary outcome was freedom from death during LVAD support. Secondary endpoints included freedom from unexpected death, likelihood of transplantation and recovery, and adverse events. Among 16,384 eligible patients in the Interagency Registry for Mechanically Assisted Circulatory Support registry, 2,209 patients with an ICD and 2,209 patients without one had similar propensity scores and were included. The presence of an ICD was associated with an increased mortality risk (hazard ratio: 1.20; 95% confidence interval [CI]: 1.04 to 1.39; p = 0.013) and an increased risk of unexpected death during device support (HR: 1.33; 95% CI: 1.03 to 1.71; p = 0.03). Patients with an ICD were more likely to undergo transplantation (HR: 1.16; 95% CI: 0.99 to 1.35; p = 0.06) and less likely to have LVAD explant for recovery (HR: 0.53, 95% CI: 0.29 to 0.98; p = 0.04). Patients with an ICD had a higher rate of treated ventricular arrhythmias (rate ratio: 1.27; 95% CI: 1.10 to 1.48; p = 0.001) and rehospitalization (rate ratio: 1.08; 95% CI: 1.04 to 1.12; p < 0.0001), but rates of hemorrhagic stroke were similar (rate ratio: 1.01; 95% CI: 0.81 to 1.26; p = 0.98). Among patients with a continuous flow LVAD, the presence of an ICD was not associated with reduced mortality. Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Readmissions after implantation of axial flow left ventricular assist device.

PubMed

Hasin, Tal; Marmor, Yariv; Kremers, Walter; Topilsky, Yan; Severson, Cathy J; Schirger, John A; Boilson, Barry A; Clavell, Alfredo L; Rodeheffer, Richard J; Frantz, Robert P; Edwards, Brooks S; Pereira, Naveen L; Stulak, John M; Joyce, Lyle; Daly, Richard; Park, Soon J; Kushwaha, Sudhir S

2013-01-15

The purpose of this study was to determine the occurrence and causes of readmissions after implantation of axial flow left ventricular assist device (LVAD). Based on the REMATCH (Randomized Evaluation of Mechanical Assistance for the Treatment of Congestive Heart Failure) study experience, readmissions after LVAD implantation are thought to be frequent. We retrospectively analyzed admissions to our facility in a cohort of 115 patients implanted between January 2008 and July 2011 with the HeartMate II axial flow LVAD, of whom 42 were bridged to transplant. To account for repeated events, Andersen-Gill models were used to determine possible predictors. The patients were followed for 1.4 ± 0.9 years. There were 224 readmissions in 83 patients. The overall readmission rate was 1.64 ± 1.97 per patient-year of follow-up. The readmission rate for the first 6 months was 2.0 ± 2.3 and decreased to 1.2 ± 2.1 during subsequent follow-up. Leading causes were bleeding (66 readmissions in 34 patients), mostly gastrointestinal bleed (51 in 27 patients), cardiac (51 in 36 patients, most for HF or arrhythmia), infections (32 in 25 patients) of which 6 were pump related, and thrombosis (20 in 15 patients) including 13 readmissions due to hemolysis. Preoperative variables associated with (fewer) readmissions in a multivariate model include residence within our hospital-extended referral zone of Minnesota and the neighboring states (hazard ratio: 0.66; 95% confidence interval: 0.48 to 0.91; p = 0.011), hemoglobin (hazard ratio: 0.91, 95% confidence interval: 0.84 to 0.99; p = 0.027) and N-terminal pro-B-type natriuretic peptide (hazard ratio: 0.98; 95% confidence interval: 0.96 to 1.0 per 1,000-unit increase, p = 0.022). C-statistic for the model: 0.63. Readmission rates after axial flow LVAD implantation decrease during the first 6 months and then stabilize. The leading causes are bleeding, cardiac (heart failure and arrhythmia), infections, and thrombosis. Copyright © 2013 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Coiling of a Ruptured Large Internal Carotid Artery Aneurysm via Extracranial-Intracranial Saphenous Vein Bypass Graft Just After Proximal Ligation of the Internal Carotid Artery.

PubMed

Tajima, Hayato; Araki, Yoshio; Izumi, Takashi; Nishihori, Masahiro; Okamoto, Sho; Wakabayashi, Toshihiko

2017-02-01

Combined direct and endovascular surgery has been performed to treat large to giant internal carotid artery (ICA) aneurysms. This report describes successful treatment of a large ICA aneurysm by coiling of the aneurysm via an extracranial-intracranial saphenous vein (SV) graft just after bypass and ICA proximal ligation. A 66-year-old woman presented with a left ICA supraclinoid aneurysm with progressive visual field defect and impaired visual acuity in the left eye. While waiting for scheduled surgery, she experienced a subarachnoid hemorrhage. An extracranial-intracranial high-flow bypass using an SV graft and proximal ligation of the ICA were performed. Coiling of the aneurysm was immediately performed successfully via the SV bypass graft. The patient experienced no new neurologic deficit after this treatment. Follow-up radiologic evaluations using magnetic resonance imaging and magnetic resonance angiography revealed complete aneurysm occlusion. Aneurysm coiling via an extracranial-intracranial SV bypass graft could offer an alternative when an antegrade access route to the ICA is not used because of prior parent artery ligation. Copyright © 2016 Elsevier Inc. All rights reserved.

A static investigation of yaw vectoring concepts on two-dimensional convergent-divergent nozzles

NASA Technical Reports Server (NTRS)

Berrier, B. L.; Mason, M. L.

1983-01-01

The flow-turning capability and nozzle internal performance of yaw-vectoring nozzle geometries were tested in the NASA Langley 16-ft Transonic wind tunnel. The concept was investigated as a means of enhancing fighter jet performance. Five two-dimensional convergent-divergent nozzles were equipped for yaw-vectoring and examined. The configurations included a translating left sidewall, left and right sidewall flaps downstream of the nozzle throat, left sidewall flaps or port located upstream of the nozzle throat, and a powered rudder. Trials were also run with 20 deg of pitch thrust vectoring added. The feasibility of providing yaw-thrust vectoring was demonstrated, with the largest yaw vector angles being obtained with sidewall flaps downstream of the nozzle primary throat. It was concluded that yaw vector designs that scoop or capture internal nozzle flow provide the largest yaw-vector capability, but decrease the thrust the most.

Earth observations taken from shuttle orbiter Discovery on STS-70 mission

NASA Image and Video Library

1995-07-21

STS070-717-011 (13-22 JULY 1995) --- Volcanic landscapes with a thin dusting of snow appear in this near-vertical view of the dry, high spine of the Andes Mountains at around 28 degrees south latitude. Strong westerly winds (from left) have blown the snow off the highest volcanic peaks (center and bottom): many of these peaks rise higher than 20,000 feet. A small, dry lake appears top right, the white color derived from salts. The border between Argentina and Chile winds from volcano to volcano and passes just left of the small blue lake (left center). Black lava flows can be detected bottom right. The larger area of brown-pink rocks (bottom rock) is also an area of volcanic rocks, of a type known as ash flow tuffs which are violently extruded, often in volumes measured in cubic kilometers.

Orthogonal Views of Coronary Vessels: A Method for Imaging the Delivery of Blood Cardioplegia Using Transesophageal Echocardiography.

PubMed

Maracaja Neto, Luiz F; Modak, Raj; Schonberger, Robert B

2017-04-01

Coronary blood flow can be disrupted during cardiac interventions such as mitral valve surgeries, left atrial appendage ligation, transcatheter aortic valve implantation, and aortic procedures involving reimplantation of coronary buttons. Although difficult to accomplish, coronary imaging using transesophageal echocardiography can be performed by the use of orthogonal imaging with the ability for real-time tilt for angle adjustment. The technique described herein allows imaging of the right coronary artery, left main coronary artery bifurcation, left anterior descending, and circumflex coronary arteries. The imaging is facilitated by acquisition during the delivery of blood cardioplegia. Coronary sinus and great cardiac vein imaging also can be obtained during the delivery of retrograde cardioplegia. Although further studies are needed, this imaging technique may prove useful in procedures where coronary flow disruption is suspected or as an additional parameter to confirm delivery of cardioplegia.

External carotid compression: a novel technique to improve cerebral perfusion during selective antegrade cerebral perfusion for aortic arch surgery.

PubMed

Grocott, Hilary P; Ambrose, Emma; Moon, Mike

2016-10-01

Selective antegrade cerebral perfusion (SACP) involving cannulation of either the axillary or innominate artery is a commonly used technique for maintaining cerebral blood flow (CBF) during the use of hypothermic cardiac arrest (HCA) for operations on the aortic arch. Nevertheless, asymmetrical CBF with hypoperfusion of the left cerebral hemisphere is a common occurrence during SACP. The purpose of this report is to describe an adjunctive maneuver to improve left hemispheric CBF during SACP by applying extrinsic compression to the left carotid artery. A 77-yr-old male patient with a history of aortic valve replacement presented for emergent surgical repair of an acute type A aortic dissection of a previously known ascending aortic aneurysm. His intraoperative course included cannulation of the right axillary artery, which was used as the aortic inflow during cardiopulmonary bypass and also allowed for subsequent SACP during HCA. After the onset of HCA, the innominate artery was clamped at its origin to allow for SACP. Shortly thereafter, however, the left-sided cerebral oxygen saturation (SrO2) began to decrease. Augmenting the PaO2, PaCO2 and both SACP pressure and flow failed to increase left hemispheric SrO2. Following the use of ultrasound guidance to confirm the absence of atherosclerotic disease in the carotid artery, external pressure was applied partially compressing the artery. With the carotid compression, the left cerebral saturation abruptly increased, suggesting pressurization of the left cerebral hemispheric circulation and augmentation of CBF. Direct ultrasound visualization and cautious partial compression of the left carotid artery may address asymmetrical CBF that occurs with SACP during HCA for aortic arch surgery. This strategy may lead to improved symmetry of CBF and corresponding cerebral oximetry measurements during aortic arch surgery.

Increased regional cerebral blood flow in the contralateral thalamus after successful motor cortex stimulation in a patient with poststroke pain.

PubMed

Saitoh, Youichi; Osaki, Yasuhiro; Nishimura, Hiroshi; Hirano, Shun-ichiro; Kato, Amami; Hashikawa, Kazuo; Hatazawa, Jun; Yoshimine, Toshiki

2004-05-01

The mechanisms underlying poststroke pain have not been clearly identified. Although motor cortex stimulation (MCS) sometimes reduces poststroke pain successfully, the exact mechanism is not yet known. For further investigation of the neural pathways involved in the processing of poststroke pain and in pain reduction by MCS, the authors used positron emission tomography (PET) scanning to determine significant changes in regional cerebral blood flow (rCBF). This 58-year-old right-handed man suffered from right-sided poststroke pain for which he underwent implantation of a stimulation electrode in the right motor cortex. After 30 minutes of stimulation, his pain was remarkably reduced (Visual Analog Scale scores decreased 8 to 1) and he felt warmth in his left arm. The rCBF was studied using PET scanning with 15O-labeled water when the patient was in the following states: before MCS (painful condition, no stimulation) and after successful MCS (painless condition, no stimulation). The images were analyzed using statistical parametric mapping software. State-dependent differences in global blood flow were covaried using analysis of covariance. Comparisons of the patient's rCBF in the painful condition with that in the painless condition revealed significant rCBF increases in the left rectus gyrus (BA11), left superior frontal lobe (BA9), left anterior cingulate gyms (BA32), and the left thalamus (p < 0.05, corrected). On the other hand, there were significant decreases in rCBF in the right superior temporal gyrus (BA22, p < 0.01, corrected) and the left middle occipital gyrus (BA19, p < 0.05, corrected). The efficacy of MCS was mainly related to increased synaptic activity in the thalamus, whereas the activations in the rectus gyrus, anterior cingulate gyrus, and superior frontal cortex as well as the inactivation of the superior temporal lobe may be related to emotional processes. This is the first report in which the contralateral thalamus was significantly activated and pain relief was achieved using MCS.

Achieving low anastomotic leak rates utilizing clinical perfusion assessment.

PubMed

Kream, Jacob; Ludwig, Kirk A; Ridolfi, Timothy J; Peterson, Carrie Y

2016-10-01

Anastomotic leak after colorectal resection increases morbidity, mortality, and in the setting of cancer, increases recurrences rates and reduces survival odds. Recent reports suggest that fluorescence evaluation of perfusion after colorectal anastomosis creation is associated with low anastomotic leak rates (1.4%). The purpose of this work was to evaluate whether a similar low anastomotic leak rate after left-sided colorectal resections could be achieved using standard assessment of blood flow to the bowel ends. We performed a retrospective chart review at an academic tertiary referral center, evaluating 317 consecutive patients who underwent a pelvic anastomosis after sigmoid colectomy, left colectomy, or low anterior resection. All operations were performed by a single surgeon from March 2008 to January 2015 with only standard clinical measures used to assess perfusion to the bowel ends. The primary outcome measure was the anastomotic leak rate as diagnosed by clinical symptoms, exam, or routine imaging. The average patient age was 59.7 years with an average body mass index of 28.8 kg/m(2). Rectal cancer (128, 40.4%) was the most common indication for operation while hypertension (134, 42.3%) was the most common comorbidity. In total, 177 operations were laparoscopic (55.8%), 13 were reoperative resections (4.1%), and 108 were protected with a loop ileostomy (34.1%). Preoperative chemotherapy was administered to 25 patients (7.9%) while preoperative chemo/radiation was administered to 64 patients (20.2%). The anastomotic leak rate was 1.6% (5/317). Our data suggests that standard, careful evaluation of adequate blood flow via inspection and confirmation of pulsatile blood flow to the bowel ends and meticulous construction of the colorectal or coloanal anastomoses can result in very low leak rates, similar to the rate reported when intraoperative imaging is used to assess perfusion. Copyright © 2016 Elsevier Inc. All rights reserved.

Low-gradient aortic stenosis.

PubMed

Clavel, Marie-Annick; Magne, Julien; Pibarot, Philippe

2016-09-07

An important proportion of patients with aortic stenosis (AS) have a 'low-gradient' AS, i.e. a small aortic valve area (AVA <1.0 cm(2)) consistent with severe AS but a low mean transvalvular gradient (<40 mmHg) consistent with non-severe AS. The management of this subset of patients is particularly challenging because the AVA-gradient discrepancy raises uncertainty about the actual stenosis severity and thus about the indication for aortic valve replacement (AVR) if the patient has symptoms and/or left ventricular (LV) systolic dysfunction. The most frequent cause of low-gradient (LG) AS is the presence of a low LV outflow state, which may occur with reduced left ventricular ejection fraction (LVEF), i.e. classical low-flow, low-gradient (LF-LG), or preserved LVEF, i.e. paradoxical LF-LG. Furthermore, a substantial proportion of patients with AS may have a normal-flow, low-gradient (NF-LG) AS: i.e. a small AVA-low-gradient combination but with a normal flow. One of the most important clinical challenges in these three categories of patients with LG AS (classical LF-LG, paradoxical LF-LG, and NF-LG) is to differentiate a true-severe AS that generally benefits from AVR vs. a pseudo-severe AS that should be managed conservatively. A low-dose dobutamine stress echocardiography may be used for this purpose in patients with classical LF-LG AS, whereas aortic valve calcium scoring by multi-detector computed tomography is the preferred modality in those with paradoxical LF-LG or NF-LG AS. Although patients with LF-LG severe AS have worse outcomes than those with high-gradient AS following AVR, they nonetheless display an important survival benefit with this intervention. Some studies suggest that transcatheter AVR may be superior to surgical AVR in patients with LF-LG AS. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For permissions please email: journals.permissions@oup.com.

Gain-scheduling multivariable LPV control of an irrigation canal system.

PubMed

Bolea, Yolanda; Puig, Vicenç

2016-07-01

The purpose of this paper is to present a multivariable linear parameter varying (LPV) controller with a gain scheduling Smith Predictor (SP) scheme applicable to open-flow canal systems. This LPV controller based on SP is designed taking into account the uncertainty in the estimation of delay and the variation of plant parameters according to the operating point. This new methodology can be applied to a class of delay systems that can be represented by a set of models that can be factorized into a rational multivariable model in series with left/right diagonal (multiple) delays, such as, the case of irrigation canals. A multiple pool canal system is used to test and validate the proposed control approach. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

Acoustic Cluster Therapy: In Vitro and Ex Vivo Measurement of Activated Bubble Size Distribution and Temporal Dynamics.

PubMed

Healey, Andrew John; Sontum, Per Christian; Kvåle, Svein; Eriksen, Morten; Bendiksen, Ragnar; Tornes, Audun; Østensen, Jonny

2016-05-01

Acoustic cluster technology (ACT) is a two-component, microparticle formulation platform being developed for ultrasound-mediated drug delivery. Sonazoid microbubbles, which have a negative surface charge, are mixed with micron-sized perfluoromethylcyclopentane droplets stabilized with a positively charged surface membrane to form microbubble/microdroplet clusters. On exposure to ultrasound, the oil undergoes a phase change to the gaseous state, generating 20- to 40-μm ACT bubbles. An acoustic transmission technique is used to measure absorption and velocity dispersion of the ACT bubbles. An inversion technique computes bubble size population with temporal resolution of seconds. Bubble populations are measured both in vitro and in vivo after activation within the cardiac chambers of a dog model, with catheter-based flow through an extracorporeal measurement flow chamber. Volume-weighted mean diameter in arterial blood after activation in the left ventricle was 22 μm, with no bubbles >44 μm in diameter. After intravenous administration, 24.4% of the oil is activated in the cardiac chambers. Copyright © 2016 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

A new self-expandable aortic valved stent deployed above native leaflets for aortic insufficiency: an in vitro study.

PubMed

Huang, H; Zhou, Y; Shao, J; Cai, J; Mei, Y; Wang, Y

2012-12-01

The aim of this paper was to develop a new self-expandable aortic valved stent following the shape of the sinus of Valsalva, which can be deployed above native leaflets for aortic regurgitation, and study it's effect on coronary artery flow when orthotopic implantation in and above native leaflets. New self-expandable aortic valved stent consist of nitinol stent and bovine pericardium, and was designed following the shape of the sinus of Valsalva, the bovine pericardium was tailed as native leaflet. Thirty-six swine hearts were divided into three equal groups of twelve. In Group A (N.=12), the new self-expandable aortic valved stents deployed in native leaflets. In Group B (N.=12), the new self-expandable aortic valved stents deployed above native leaflets. In Group C (N.=12), the cylinder-like valved stents deployed only in native leaflets. The measurements of each coronary flow rate and endoscopic inspections were repeated post-implantation. In Group A and C, valve implantation in native leaflets resulted in a significant decrease in both left and right coronary flows. In Group B, no significant change in either right or left coronary flow was found after new self-expandable aortic valved stent placement. Endoscopic inspections showed that in group A and C the native leaflets sandwiched between valved stent and aortic wall, whereas, in group B the native leaflets were under the artificial leaflets. Two kinds of stents deployed in native leaflets affect left and right coronary flows significantly. No significant effect was found when the new self-expandable aortic valved stent deployed above native leaflets. This new self-expandable aortic valved stent can be deployed above the native leaflets, which avoids the obstruction of native leaflets on coronary flow.

Transthoracic Coronary Flow Data at Rest Predict High-Risk Stress Tests.

PubMed

Zagatina, Angela; Zhuravskaya, Nadezhda; Vareldzhyan, Yuliya; Kamenskikh, Maxim; Shmatov, Dmitry; Benacka, Jozef; Kucera, Martin; Kruzliak, Peter

2018-06-01

Background Several recent studies have reported the opportunity to diagnose significant narrowing of the coronary arteries without stress testing using local flow acceleration. Purpose To define how often patients with increased coronary flow velocities at rest (≥ 0.70 m/s) have a positive exercise echocardiography test. Material and Methods A total of 150 patients scheduled for exercise echocardiography were studied using transthoracic Doppler echocardiography in order to assess coronary artery flow velocity before exercise. Pulsed wave Doppler registered blood flow velocity placed on the color signal. The maximal diastolic velocity of coronary flow was measured. Results Of participants, 16% had a velocity of more than 0.70 m/s in the left main/proximal left anterior/proximal left circumflex arteries (LM/pLAD). A significant correlation was observed between the value of the maximal velocity in LM/pLAD and the ejection fraction at the peak of exercise ( r ≈ -0.39, P < 0.0001); between the value of the maximal velocity in LM/pLAD and index of wall motion abnormalities (IWMA) at the peak of exercise ( r ≈ 0.44, P < 0.0001); and between the value of the maximal velocity in LM/pLAD and dIWMA ( r ≈ 0.41, P < 0.0001). Afterwards, severe ischemia in stress echocardiography tests was observed in this group. The average IWMA of these tests was found to be 2.3. Sixty-two angiograms were available for comparison with Doppler data. Conclusion There is a significant correlation between the value of the maximal velocity in LM/pLAD/pLCx at rest and the severity of wall motion abnormalities during exercise tests.

Partitioned fluid-solid coupling for cardiovascular blood flow: left-ventricular fluid mechanics.

PubMed

Krittian, Sebastian; Janoske, Uwe; Oertel, Herbert; Böhlke, Thomas

2010-04-01

We present a 3D code-coupling approach which has been specialized towards cardiovascular blood flow. For the first time, the prescribed geometry movement of the cardiovascular flow model KaHMo (Karlsruhe Heart Model) has been replaced by a myocardial composite model. Deformation is driven by fluid forces and myocardial response, i.e., both its contractile and constitutive behavior. Whereas the arbitrary Lagrangian-Eulerian formulation (ALE) of the Navier-Stokes equations is discretized by finite volumes (FVM), the solid mechanical finite elasticity equations are discretized by a finite element (FEM) approach. Taking advantage of specialized numerical solution strategies for non-matching fluid and solid domain meshes, an iterative data-exchange guarantees the interface equilibrium of the underlying governing equations. The focus of this work is on left-ventricular fluid-structure interaction based on patient-specific magnetic resonance imaging datasets. Multi-physical phenomena are described by temporal visualization and characteristic FSI numbers. The results gained show flow patterns that are in good agreement with previous observations. A deeper understanding of cavity deformation, blood flow, and their vital interaction can help to improve surgical treatment and clinical therapy planning.

Effect of the degree of LAD stenosis on "competitive flow" and flow field characteristics in LIMA-to-LAD bypass surgery.

PubMed

Swillens, Abigail; De Witte, Marloes; Nordgaard, Håvard; Løvstakken, Lasse; Van Loo, Denis; Trachet, Bram; Vierendeels, Jan; Segers, Patrick

2012-08-01

The long-term patency of the left internal mammary artery (LIMA) in left anterior descending (LAD) coronary stenosis bypass surgery is believed to be related to the degree of competitive flow between the LAD and LIMA. To investigate the effect of the LAD stenosis severity on this phenomenon and on haemodynamics in the LIMA and anastomosis region, a numerical LIMA-LAD model was developed based on 3D geometric (obtained from a cast) and hemodynamic data from an experimental pig study. Proximal LAD pressure was used as upstream boundary condition. The model counted 13 outlets (12 septal arteries and the distal LAD) where flow velocities were imposed in systole, while myocardial conductance was imposed in diastole via an implicit scheme. LAD stenoses of 100 (total occlusion), 90, 75 and 0 % area reduction were constructed. Low degree of LAD stenosis was associated with highly competitive flow and low wall shear stress (WSS) in the LIMA, an unfavourable hemodynamic regime which might contribute to WSS-related remodelling of the LIMA and suboptimal long-term LIMA bypass performance.

Computational Modeling of Blood Flow and Valve Dynamics in Hearts with Hypertrophic Cardiomyopathy

NASA Astrophysics Data System (ADS)

Zheng, Xudong; Mittal, Rajat; Abraham, Theodore; Pinheiro, Aurelio

2010-11-01

Hypertrophic Cardiomyopathy (HCM) is a cardiovascular disease manifested by the thickening of the ventricular wall and often leads to a partial obstruction to the blood flow out of the left ventricle. HCM is recognized as one of the most common causes of sudden cardiac death in athletes. In a heart with HCM, the hypertrophy usually narrows the blood flow pathway to the aorta and produces a low pressure zone between the mitral valve and the hypertrophy during systole. This low pressure can suck the mitral valve leaflet back and completely block the blood flow into the aorta. In the current study, a sharp interface immersed boundary method flow solver is employed to study the hemodynamics and valve dynamics inside a heart with HCM. The three-dimensional motion and configuration of the left ventricle including mitral valve leaflets and aortic valves are reconstructed based on echo-cardio data sets. The mechanisms of aortic obstruction associated with HCM are investigated. The long term objective of this study is to develop a computational tool to aid in the assessment and surgical management of HCM.

Lung volumes, ventricular function and pulmonary arterial flow in children operated on for left-sided congenital diaphragmatic hernia: long-term results.

PubMed

Abolmaali, Nasreddin; Koch, Arne; Götzelt, Knut; Hahn, Gabriele; Fitze, Guido; Vogelberg, Christian

2010-07-01

To compare MRI-based functional pulmonary and cardiac measurements in the long-term follow-up of children operated on for left-sided congenital diaphragmatic hernia (CDH) with age- and body size-matched healthy controls. Twelve children who received immediate postnatal surgery for closure of isolated left-sided CDH were included and received basic medical examinations, pulmonary function testing and echocardiography. MRI included measurement of lung volume, ventricular function assessment and velocity-encoded imaging of the pulmonary arteries and was compared with the data for 12 healthy children matched for age and body size. While patients' clinical test results were not suspicious, comparison between the MRI data for patients and those for healthy controls revealed significant differences. In patients, the volumes of the left lungs were increased and the tidal volume was larger on the right side. While the stroke volumes of both ventricles were reduced, heart rate and ejection fraction were increased. Flow, acceleration time and cross-sectional area of the left pulmonary artery were reduced. Functional MRI detected pulmonary and cardiac findings in the late follow-up of CDH children which may be missed by standard clinical methods and might be relevant for decisions regarding late outcome and treatment.

Effects of heart rate on experimentally produced mitral regurgitation in dogs.

PubMed

Yoran, C; Yellin, E L; Hori, M; Tsujioka, K; Laniado, S; Sonnenblick, E H; Frater, R W

1983-12-01

The effects of increasing heart rate (HR) on the hemodynamics of acute mitral regurgitation (MR) were studied in 8 open-chest dogs. Filling volume, regurgitant volume and stroke volume were calculated from electromagnetic probe measurements of mitral and aortic flows. The left atrial-left ventricular systolic pressure gradient was measured with micromanometers. The calculated effective mitral regurgitant orifice area varied from 10 to 128 mm2, with a consequent regurgitant fraction (regurgitant volume/filling volume) of 24 to 62%. After crushing the sinus node, HR was increased stepwise from 90 to 180 beats/min by atrial pacing while maintaining aortic pressure constant. With increasing HR, filling volume, stroke volume, regurgitant volume and regurgitant time decreased; total cardiac output, forward cardiac output, regurgitant output, systolic pressure gradient, regurgitant fraction and the regurgitant orifice did not change; left ventricular end-diastolic pressure decreased; and left atrial v-wave amplitude increased. These results indicate that in acute experimental MR with a wide spectrum of incompetence, the relative distribution of forward and regurgitant flows did not change with large increases in HR. At rates greater than 150 beats/min the atrial contraction occurs early and increases the amplitude of the left atrial v wave. This may contribute to the severity of pulmonary congestion in patients with MR.

Multicenter Evaluation of Octreotide as Secondary Prophylaxis in Patients With Left Ventricular Assist Devices and Gastrointestinal Bleeding.

PubMed

Shah, Keyur B; Gunda, Sampath; Emani, Sitaramesh; Kanwar, Manreet K; Uriel, Nir; Colombo, Paolo C; Uber, Patricia A; Sears, Melissa L; Chuang, Joyce; Farrar, David J; Brophy, Donald F; Smallfield, George B

2017-11-01

Gastrointestinal (GI) bleeding is one of the most common complications after continuous-flow left ventricular assist device implantation. More than one third of patients with incident bleed go on to develop recurrent GI bleeding. Octreotide, a somatostatin analog, is proposed to reduce the risk of recurrent GI bleeding in this population. This multicenter, retrospective analysis evaluated 51 continuous-flow left ventricular assist device patients who received secondary prophylaxis with octreotide after their index GI bleed from 2009 to 2015. All patients had a hospitalization for GI bleed and received octreotide after discharge. Patient demographics, medical and medication history, and clinical characteristics of patients who rebled after receiving octreotide were compared with non-rebleeders. These data were also compared with matched historical control patients previously enrolled in the HMII (HeartMate II) clinical trials, none of whom received octreotide, to provide a context for the bleeding rates. Twelve patients (24%) who received secondary octreotide prophylaxis developed another GI bleed, whereas 39 (76%) did not. There were similar intergroup demographics; however, significantly more bleeders had a previous GI bleeding history before left ventricular assist device placement (33% versus 5%; P =0.02) and greater frequency of angiodysplasia confirmed during endoscopy (58% versus 23%; P =0.03). Fewer patients in this study experienced a recurrent GI bleed compared with a matched historical control group that did not receive octreotide (24% versus 43%; P =0.04). Patients with continuous-flow left ventricular assist device receiving secondary prophylaxis with octreotide had a significantly lower GI bleed recurrence compared with historical controls not treated with octreotide. Additional prospective studies are needed to confirm these data. © 2017 American Heart Association, Inc.

Label-free in vivo optical imaging of functional microcirculations within meninges and cortex in mice.

PubMed

Jia, Yali; Wang, Ruikang K

2010-12-15

Abnormal microcirculation within meninges is common in many neurological diseases. There is a need for an imaging method that is capable of monitoring dynamic meningeal microcirculations, preferably decoupled from cortical blood flow. Optical microangiography (OMAG) is a recently developed label-free imaging method capable of producing 3D images of dynamic blood perfusion within micro-circulatory tissue beds at an imaging depth up to ∼2 mm, with an unprecedented imaging sensitivity to blood flow at ∼4 μm/s. In this paper, we demonstrate the utility of OMAG in imaging the detailed blood flow distributions, at a capillary level resolution, within the meninges and cortex in mice with the cranium left intact. Using a thrombotic mouse model, we show that the OMAG can yield longitudinal measurements of meningeal vascular responses to the insult and can decouple these responses from those in the cortex, giving valuable information regarding the localized hemodynamics along with the dynamic formation of thrombotic event. The results indicate that OMAG can be a useful tool to study therapeutic strategies in preclinical animal models in order to mitigate various pathologies that are mainly related to the meningeal circulations. Copyright © 2010 Elsevier B.V. All rights reserved.

Non-Invasive Mapping of Intraventricular Flow Patterns in Patients Treated with Left Ventricular Assist Devices

NASA Astrophysics Data System (ADS)

Miramontes, Marissa; Rossini, Lorenzo; Braun, Oscar; Brambatti, Michela; Almeida, Shone; Mizeracki, Adam; Martinez-Legazpi, Pablo; Benito, Yolanda; Bermejo, Javier; Kahn, Andrew; Adler, Eric; Del Álamo, Juan C.

2017-11-01

In heart failure patients, left ventricular (LV) assist devices (LVADs) decrease mortality and improve quality of life. We hypothesize echo color Doppler velocimetry (echo-CDV), an echocardiographic flow mapping modality, can non-invasively characterize the effect of LVAD support, optimize the device, thereby decreasing the stoke rate present in these patients. We used echo-CDV to image LV flow at baseline LVAD speed and during a ramp test in LVAD patients (Heartmate II, N =10). We tracked diastolic vortices and mapped blood stasis and cumulative shear. Compared to dilated cardiomyopathy (DCM) patients without LVADs, the flow had a less prominent diastolic vortex ring, and transited directly from mitral valve to cannula. Residence time and shear were significantly lower compared to healthy controls and DCMs. Aortic regurgitation and a large LV vortex presence or a direct mitral jet towards the cannula affected blood stasis region location and size. Flow patterns, residence time and shear depended on LV geometry, valve function and LVAD speed in a patient specific manner. This new methodology could be used with standard echo, hemodynamics and clinical information to find the flow optimizing LAVD setting minimizing stasis for each patient.

Coronary oscillatory flow amplitude is more affected by perfusion pressure than ventricular pressure.

PubMed

Krams, R; Sipkema, P; Westerhof, N

1990-06-01

In this study on the isolated, maximally vasodilated, blood-perfused cat heart we investigated the relation between left ventricular developed pressure (delta Piv) and coronary oscillatory flow amplitude (diastolic minus systolic flow, delta F) at different levels of constant perfusion pressure (Pp). We hypothesized that the effect of cardiac contraction on the phasic flow results from the changing elastic properties of cardiac muscle. The coronary vessel compartment can, as can the left ventricular lumen compartment, be described by a time-varying elastance. This concept predicts that the effect of left ventricular pressure on delta F is small, whereas the effect of Pp is considerable. Both the waterfall model and the intramyocardial pump model predict the inverse. The relation between delta Piv and delta F at a Pp of 10 kPa is delta F = (4.71 +/- 3.08).delta Piv + 337 +/- 75 (slope in ml.min-1.100 g-1.kPa-1 and intercept in ml.min-1.100 g-1; n = 7); the relation between (constant levels of) Pp and delta F at a constant delta Piv of 10 kPa is delta F = 51.Pp + 211 (slope in ml.min-1.100 g-1.kPa-1 and intercept in ml.min-1.100 g-1; n = 6). The differences in slope are best predicted by the time-varying elastance concept.

Variability of mammary blood flow in lactating Holstein-Friesian cows during the first twelve weeks of lactation.

PubMed

Götze, A; Honnens, A; Flachowsky, G; Bollwein, H

2010-01-01

The goals of the present study were to measure mammary blood flow volume (BFV) during the first 12 wk of lactation in dairy cows by using color Doppler sonography and to determine what affects the mammary blood flow. Forty cows were examined via color Doppler sonography on d 1, 7, 14, 28, 56, and 84 after parturition (d 0). The total BFV (BFV(total)) to the 4 mammary glands was calculated by measuring time-averaged maximum velocities (TAMV) and cross-sectional areas (A) of the left and right pudendoepigastric trunks via transrectal color Doppler sonography. Because there were no significant differences in A, TAMV, and BFV between the right and left pudendoepigastric trunks, the means of A and TAMV, and the BFV(total) of both trunks were used for calculations. The intraindividual and interindividual variability of repeated BFV measures quantified by intraclass correlation coefficients were 96 and 98%, respectively. The BFV(total) ranged from 19.9 to 27.9 L/min, with a mean of 22.3+/-4.9 L/min. Interindividual differences in BFV values were attributable to variations in A and TAMV. The interindividual variability of the BFV(total), which was determined using the coefficients of variation of the BFV(total) on individual days, ranged from 16 to 28%. All the cows had similar changes in the BFV(total) during the study. Changes in BFV(total) were not correlated with changes in the mean of A, but there was a good correlation between changes in BFV(total) and in the mean of TAMV (r=0.94). The BFV(total) was highest on d 1 of lactation, decreased 28% by d 7, and remained at this level until d 28. By d 56, the BFV(total) had increased by 15% compared with d 14 and by 10% compared with d 28. The BFV(total) on d 84 was significantly different from all other days except d 56. There were moderate correlations between daily milk yield and BFV on individual days (0.24

Good appearance of food gives an appetizing impression and increases cerebral blood flow of frontal pole in healthy subjects.

PubMed

Koyama, Ken Ichiro; Amitani, Haruka; Adachi, Ryo; Morimoto, Toshiki; Kido, Megumi; Taruno, Yuka; Ogata, Keizaburo; Amitani, Marie; Asakawa, Akihiro; Inui, Akio

2016-01-01

We investigated the effect of food appearance on appetite and on left-frontal pole blood flow in healthy young subjects. The iEat, a new form of foods with good appearance and greater softness was hypothesized to have the better effects to the subjects than blender-processed foods. The effect on appetite and left-frontal pole blood flow using hemoencephalography was assessed while participants were viewing the slideshows of two kinds of foods respectively. The slideshows were used to control the showing time and other variables. The pictures of iEat foods stimulated both of them more than the blender-processed ones. The measurement of cerebral blood flow could be a useful method to monitor the cognitive and emotional aspects of feeding behavior that are important for humans. Like iEat, the foods that look as good as ordinary food yet are softer can be used for people with poor appetite and eating difficulties to ordinary food.

Computational solution of the velocity and wall shear stress distribution inside a left carotid artery under pulsatile flow conditions

NASA Astrophysics Data System (ADS)

Arslan, Nurullah; Turmuş, Hakan

2014-08-01

Stroke is still one of the leading causes for death after heart diseases and cancer in all over the world. Strokes happen because an artery that carries blood uphill from the heart to the head is clogged. Most of the time, as with heart attacks, the problem is atherosclerosis, hardening of the arteries, calcified buildup of fatty deposits on the vessel wall. In this study, the fluid dynamic simulations were done in a left carotid bifurcation under the pulsatile flow conditions computationally. Pulsatile flow waveform is given in the paper. In vivo geometry and boundary conditions were obtained from a patient who has stenosis located at external carotid artery (ECA) and internal carotid artery (ICA) of his common carotid artery (CCA). The location of critical flow fields such as low wall shear stress (WSS), stagnation regions and separation regions were detected near the highly stenosed region and at branching region.

Successful embolization using interlocking detachable coils for a congenital extrahepatic portosystemic venous shunt in a child.

PubMed

Yamagami, Takuji; Yoshimatsu, Rika; Matsumoto, Tomohiro; Terayama, Koshi; Nishiumra, Akira; Maeda, Yousuke; Nishimura, Tsunehiko

2007-11-01

The authors report the case of a 6-year-old boy with a congenital extrahepatic portosystemic venous shunt. He had hyperammonemia. The shunt was 18 mm in diameter and located between the inferior mesenteric vein and the left internal iliac vein. The flow in the shunt was very rapid. After decreasing blood flow by inflating a balloon catheter inserted into the left internal iliac vein from the femoral vein, a microcatheter was coaxially advanced to the shunt to embolize the shunt. Embolization was successfully performed with interlocking detachable coils and microcoils without any complication. This patient's hyperammonemia resolved soon after the procedure.

Myocardial oxygen delivery after experimental hemorrhagic shock.

PubMed Central

Archie, J P; Mertz, W R

1978-01-01

The two components of myocardial oxygen delivery, coronary blood flow to capillaries and diffusion from capillaries to mitochondria, were studied in six dogs, (1) prior to shock, (2) after three hours of hemorrhage shock at a mean systemic arterial pressure of 40 torr, (3) after reinfusion of shed blood, and (4) during the irreversible late posttransfusion stage. There was a maldistribution of left ventricular coronary flow during late shock consistent with subendocardial ischemia. Cardiac performance was significantly impaired after resuscitation and all dogs became irreversible. Total and regional left ventricular coronary blood flow and myocardial oxygen delivery to capillaries were significantly greater than preshock values in (3) but not different from preshock values in (4). However, the myocardial oxygen diffusion area to distance ratio was significantly lower than preshock values in (3), and slightly lower in (4). These data suggest that myocardial oxygen diffusion may be impaired in the early post transfusion period, (3). Accordingly, the probable etiology of left ventricular dysfunction and possibly irreversibility after resuscitation from hemorrhagic shock is subendocardial ischemia during shock with either post-resuscitation impairment of myocardial oxygen diffusion, or in cellular oxygen utilization, or both. PMID:629622

Sternal uptake of 99mTc-MAA in thoracic outlet syndrome.

PubMed

Matsusaka, Yohji; Nakahara, Tadaki; Iwabuchi, Yu; Kameyama, Masashi; Murakami, Koji

2015-12-01

Tc-macroaggregated albumin (MAA) uptake in the vertebrae has been reported in central vein occlusion, although its sternal uptake is rarely seen. We present a case in which Tc-MAA SPECT/CT showed spotty uptake in the sternum. Contrast-enhanced CT revealed marked narrowing of the left subclavian vein at the thoracic outlet with a developed collateral vein running, in the left anterior chest subcutaneous tissue, between the sternum and left axilla. In this case, IV injection of Tc-MAA from the left forearm probably led to bone marrow uptake in the sternum due to retrograde venous flow through the collateral vein.

Impact of competitive flow on wall shear stress in coronary surgery: computational fluid dynamics of a LIMA-LAD model.

PubMed

Nordgaard, Håvard; Swillens, Abigail; Nordhaug, Dag; Kirkeby-Garstad, Idar; Van Loo, Denis; Vitale, Nicola; Segers, Patrick; Haaverstad, Rune; Lovstakken, Lasse

2010-12-01

Competitive flow from native coronary vessels is considered a major factor in the failure of coronary bypass grafts. However, the pathophysiological effects are not fully understood. Low and oscillatory wall shear stress (WSS) is known to induce endothelial dysfunction and vascular disease, like atherosclerosis and intimal hyperplasia. The aim was to investigate the impact of competitive flow on WSS in mammary artery bypass grafts. Using computational fluid dynamics, WSS was calculated in a left internal mammary artery (LIMA) graft to the left anterior descending artery in a three-dimensional in vivo porcine coronary artery bypass graft model. The following conditions were investigated: high competitive flow (non-significant coronary lesion), partial competitive flow (significant coronary lesion), and no competitive flow (totally occluded coronary vessel). Time-averaged WSS of LIMA at high, partial, and no competitive flow were 0.3-0.6, 0.6-3.0, and 0.9-3.0 Pa, respectively. Further, oscillatory WSS quantified as the oscillatory shear index (OSI) ranged from (maximum OSI = 0.5 equals zero net WSS) 0.15 to 0.35, <0.05, and <0.05, respectively. Thus, high competitive flow resulted in substantial oscillatory and low WSS. Moderate competitive flow resulted in WSS and OSI similar to the no competitive flow condition. Graft flow is highly dependent on the degree of competitive flow. High competitive flow was found to produce unfavourable WSS consistent with endothelial dysfunction and subsequent graft narrowing and failure. Partial competitive flow, however, may be better tolerated as it was found to be similar to the ideal condition of no competitive flow.

Repeated measurements of cerebral blood flow in the left superior temporal gyrus reveal tonic hyperactivity in patients with auditory verbal hallucinations: a possible trait marker

PubMed Central

Homan, Philipp; Kindler, Jochen; Hauf, Martinus; Walther, Sebastian; Hubl, Daniela; Dierks, Thomas

2013-01-01

Background: The left superior temporal gyrus (STG) has been suggested to play a key role in auditory verbal hallucinations (AVH) in patients with schizophrenia. Methods: Eleven medicated subjects with schizophrenia and medication-resistant AVH and 19 healthy controls underwent perfusion magnetic resonance (MR) imaging with arterial spin labeling (ASL). Three additional repeated measurements were conducted in the patients. Patients underwent a treatment with transcranial magnetic stimulation (TMS) between the first 2 measurements. The main outcome measure was the pooled cerebral blood flow (CBF), which consisted of the regional CBF measurement in the left STG and the global CBF measurement in the whole brain. Results: Regional CBF in the left STG in patients was significantly higher compared to controls (p < 0.0001) and to the global CBF in patients (p < 0.004) at baseline. Regional CBF in the left STG remained significantly increased compared to the global CBF in patients across time (p < 0.0007), and it remained increased in patients after TMS compared to the baseline CBF in controls (p < 0.0001). After TMS, PANSS (p = 0.003) and PSYRATS (p = 0.01) scores decreased significantly in patients. Conclusions: This study demonstrated tonically increased regional CBF in the left STG in patients with schizophrenia and auditory hallucinations despite a decrease in symptoms after TMS. These findings were consistent with what has previously been termed a trait marker of AVH in schizophrenia. PMID:23805093

Left frontal hub connectivity delays cognitive impairment in autosomal-dominant and sporadic Alzheimer’s disease

PubMed Central

Franzmeier, Nicolai; Düzel, Emrah; Jessen, Frank; Buerger, Katharina; Levin, Johannes; Duering, Marco; Dichgans, Martin; Haass, Christian; Suárez-Calvet, Marc; Fagan, Anne M; Paumier, Katrina; Benzinger, Tammie; Masters, Colin L; Morris, John C; Perneczky, Robert; Janowitz, Daniel; Catak, Cihan; Wolfsgruber, Steffen; Wagner, Michael; Teipel, Stefan; Kilimann, Ingo; Ramirez, Alfredo; Rossor, Martin; Jucker, Mathias; Chhatwal, Jasmeer; Spottke, Annika; Boecker, Henning; Brosseron, Frederic; Falkai, Peter; Fliessbach, Klaus; Heneka, Michael T; Laske, Christoph; Nestor, Peter; Peters, Oliver; Fuentes, Manuel; Menne, Felix; Priller, Josef; Spruth, Eike J; Franke, Christiana; Schneider, Anja; Kofler, Barbara; Westerteicher, Christine; Speck, Oliver; Wiltfang, Jens; Bartels, Claudia; Araque Caballero, Miguel Ángel; Metzger, Coraline; Bittner, Daniel; Weiner, Michael; Lee, Jae-Hong; Salloway, Stephen; Danek, Adrian; Goate, Alison; Schofield, Peter R; Bateman, Randall J; Ewers, Michael

2018-01-01

Abstract Patients with Alzheimer’s disease vary in their ability to sustain cognitive abilities in the presence of brain pathology. A major open question is which brain mechanisms may support higher reserve capacity, i.e. relatively high cognitive performance at a given level of Alzheimer’s pathology. Higher functional MRI-assessed functional connectivity of a hub in the left frontal cortex is a core candidate brain mechanism underlying reserve as it is associated with education (i.e. a protective factor often associated with higher reserve) and attenuated cognitive impairment in prodromal Alzheimer’s disease. However, no study has yet assessed whether such hub connectivity of the left frontal cortex supports reserve throughout the evolution of pathological brain changes in Alzheimer’s disease, including the presymptomatic stage when cognitive decline is subtle. To address this research gap, we obtained cross-sectional resting state functional MRI in 74 participants with autosomal dominant Alzheimer’s disease, 55 controls from the Dominantly Inherited Alzheimer’s Network and 75 amyloid-positive elderly participants, as well as 41 amyloid-negative cognitively normal elderly subjects from the German Center of Neurodegenerative Diseases multicentre study on biomarkers in sporadic Alzheimer’s disease. For each participant, global left frontal cortex connectivity was computed as the average resting state functional connectivity between the left frontal cortex (seed) and each voxel in the grey matter. As a marker of disease stage, we applied estimated years from symptom onset in autosomal dominantly inherited Alzheimer’s disease and cerebrospinal fluid tau levels in sporadic Alzheimer’s disease cases. In both autosomal dominant and sporadic Alzheimer’s disease patients, higher levels of left frontal cortex connectivity were correlated with greater education. For autosomal dominant Alzheimer’s disease, a significant left frontal cortex connectivity × estimated years of onset interaction was found, indicating slower decline of memory and global cognition at higher levels of connectivity. Similarly, in sporadic amyloid-positive elderly subjects, the effect of tau on cognition was attenuated at higher levels of left frontal cortex connectivity. Polynomial regression analysis showed that the trajectory of cognitive decline was shifted towards a later stage of Alzheimer’s disease in patients with higher levels of left frontal cortex connectivity. Together, our findings suggest that higher resilience against the development of cognitive impairment throughout the early stages of Alzheimer’s disease is at least partially attributable to higher left frontal cortex-hub connectivity. PMID:29462334

6. VIEW OF DAM 83, SHOWING OUTLET CHANNEL FLOWING INTO ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

6. VIEW OF DAM 83, SHOWING OUTLET CHANNEL FLOWING INTO POND A WITH DIVERSION GATES LONG EAST (LEFT) SIDE OF OUTLET CHANNEL, LOOKING SOUTH FROM DOWNSTREAM FACE OF THE DAM - Upper Souris National Wildlife Refuge, Dam 83, Souris River Basin, Foxholm, Surrey (England), ND

Low dose dynamic myocardial CT perfusion using advanced iterative reconstruction

NASA Astrophysics Data System (ADS)

Eck, Brendan L.; Fahmi, Rachid; Fuqua, Christopher; Vembar, Mani; Dhanantwari, Amar; Bezerra, Hiram G.; Wilson, David L.

2015-03-01

Dynamic myocardial CT perfusion (CTP) can provide quantitative functional information for the assessment of coronary artery disease. However, x-ray dose in dynamic CTP is high, typically from 10mSv to >20mSv. We compared the dose reduction potential of advanced iterative reconstruction, Iterative Model Reconstruction (IMR, Philips Healthcare, Cleveland, Ohio) to hybrid iterative reconstruction (iDose4) and filtered back projection (FBP). Dynamic CTP scans were obtained using a porcine model with balloon-induced ischemia in the left anterior descending coronary artery to prescribed fractional flow reserve values. High dose dynamic CTP scans were acquired at 100kVp/100mAs with effective dose of 23mSv. Low dose scans at 75mAs, 50mAs, and 25mAs were simulated by adding x-ray quantum noise and detector electronic noise to the projection space data. Images were reconstructed with FBP, iDose4, and IMR at each dose level. Image quality in static CTP images was assessed by SNR and CNR. Blood flow was obtained using a dynamic CTP analysis pipeline and blood flow image quality was assessed using flow-SNR and flow-CNR. IMR showed highest static image quality according to SNR and CNR. Blood flow in FBP was increasingly over-estimated at reduced dose. Flow was more consistent for iDose4 from 100mAs to 50mAs, but was over-estimated at 25mAs. IMR was most consistent from 100mAs to 25mAs. Static images and flow maps for 100mAs FBP, 50mAs iDose4, and 25mAs IMR showed comparable, clear ischemia, CNR, and flow-CNR values. These results suggest that IMR can enable dynamic CTP at significantly reduced dose, at 5.8mSv or 25% of the comparable 23mSv FBP protocol.

Noninvasive assessment of left atrial maximum dP/dt by a combination of transmitral and pulmonary venous flow.

PubMed

Nakatani, S; Garcia, M J; Firstenberg, M S; Rodriguez, L; Grimm, R A; Greenberg, N L; McCarthy, P M; Vandervoort, P M; Thomas, J D

1999-09-01

The study assessed whether hemodynamic parameters of left atrial (LA) systolic function could be estimated noninvasively using Doppler echocardiography. Left atrial systolic function is an important aspect of cardiac function. Doppler echocardiography can measure changes in LA volume, but has not been shown to relate to hemodynamic parameters such as the maximal value of the first derivative of the pressure (LA dP/dt(max)). Eighteen patients in sinus rhythm were studied immediately before and after open heart surgery using simultaneous LA pressure measurements and intraoperative transesophageal echocardiography. Left atrial pressure was measured with a micromanometer catheter, and LA dP/dt(max) during atrial contraction was obtained. Transmitral and pulmonary venous flow were recorded by pulsed Doppler echocardiography. Peak velocity, and mean acceleration and deceleration, and the time-velocity integral of each flow during atrial contraction was measured. The initial eight patients served as the study group to derive a multilinear regression equation to estimate LA dP/dt(max) from Doppler parameters, and the latter 10 patients served as the test group to validate the equation. A previously validated numeric model was used to confirm these results. In the study group, LA dP/dt(max) showed a linear relation with LA pressure before atrial contraction (r = 0.80, p < 0.005), confirming the presence of the Frank-Starling mechanism in the LA. Among transmitral flow parameters, mean acceleration showed the strongest correlation with LA dP/dt(max) (r = 0.78, p < 0.001). Among pulmonary venous flow parameters, no single parameter was sufficient to estimate LA dP/dt(max) with an r2 > 0.30. By stepwise and multiple linear regression analysis, LA dP/dt(max) was best described as follows: LA dP/dt(max) = 0.1 M-AC +/- 1.8 P-V - 4.1; r = 0.88, p < 0.0001, where M-AC is the mean acceleration of transmitral flow and P-V is the peak velocity of pulmonary venous flow during atrial contraction. This equation was tested in the latter 10 patients of the test group. Predicted and measured LA dP/dt(max) correlated well (r = 0.90, p < 0.0001). Numerical simulation verified that this relationship held across a wide range of atrial elastance, ventricular relaxation and systolic function, with LA dP/dt(max) predicted by the above equation with r = 0.94. A combination of transmitral and pulmonary venous flow parameters can provide a hemodynamic assessment of LA systolic function.

Noninvasive assessment of left atrial maximum dP/dt by a combination of transmitral and pulmonary venous flow

NASA Technical Reports Server (NTRS)

Nakatani, S.; Garcia, M. J.; Firstenberg, M. S.; Rodriguez, L.; Grimm, R. A.; Greenberg, N. L.; McCarthy, P. M.; Vandervoort, P. M.; Thomas, J. D.

1999-01-01

OBJECTIVES: The study assessed whether hemodynamic parameters of left atrial (LA) systolic function could be estimated noninvasively using Doppler echocardiography. BACKGROUND: Left atrial systolic function is an important aspect of cardiac function. Doppler echocardiography can measure changes in LA volume, but has not been shown to relate to hemodynamic parameters such as the maximal value of the first derivative of the pressure (LA dP/dt(max)). METHODS: Eighteen patients in sinus rhythm were studied immediately before and after open heart surgery using simultaneous LA pressure measurements and intraoperative transesophageal echocardiography. Left atrial pressure was measured with a micromanometer catheter, and LA dP/dt(max) during atrial contraction was obtained. Transmitral and pulmonary venous flow were recorded by pulsed Doppler echocardiography. Peak velocity, and mean acceleration and deceleration, and the time-velocity integral of each flow during atrial contraction was measured. The initial eight patients served as the study group to derive a multilinear regression equation to estimate LA dP/dt(max) from Doppler parameters, and the latter 10 patients served as the test group to validate the equation. A previously validated numeric model was used to confirm these results. RESULTS: In the study group, LA dP/dt(max) showed a linear relation with LA pressure before atrial contraction (r = 0.80, p < 0.005), confirming the presence of the Frank-Starling mechanism in the LA. Among transmitral flow parameters, mean acceleration showed the strongest correlation with LA dP/dt(max) (r = 0.78, p < 0.001). Among pulmonary venous flow parameters, no single parameter was sufficient to estimate LA dP/dt(max) with an r2 > 0.30. By stepwise and multiple linear regression analysis, LA dP/dt(max) was best described as follows: LA dP/dt(max) = 0.1 M-AC +/- 1.8 P-V - 4.1; r = 0.88, p < 0.0001, where M-AC is the mean acceleration of transmitral flow and P-V is the peak velocity of pulmonary venous flow during atrial contraction. This equation was tested in the latter 10 patients of the test group. Predicted and measured LA dP/dt(max) correlated well (r = 0.90, p < 0.0001). Numerical simulation verified that this relationship held across a wide range of atrial elastance, ventricular relaxation and systolic function, with LA dP/dt(max) predicted by the above equation with r = 0.94. CONCLUSIONS: A combination of transmitral and pulmonary venous flow parameters can provide a hemodynamic assessment of LA systolic function.

Management of Tricuspid Regurgitation in Patients With Hypoplastic Left Heart Syndrome.

PubMed

Pigula, Frank A; Mettler, Bret

2017-01-01

Tricuspid valve (TV) performance is critical for palliation of hypoplastic left heart syndrome. We will review current TV repair techniques, outcomes, and novel approaches. Copyright © 2017 Elsevier Inc. All rights reserved.

Fluid mechanics of blood flow in human fetal left ventricles based on patient-specific 4D ultrasound scans.

PubMed

Lai, Chang Quan; Lim, Guat Ling; Jamil, Muhammad; Mattar, Citra Nurfarah Zaini; Biswas, Arijit; Yap, Choon Hwai

2016-10-01

The mechanics of intracardiac blood flow and the epigenetic influence it exerts over the heart function have been the subjects of intense research lately. Fetal intracardiac flows are especially useful for gaining insights into the development of congenital heart diseases, but have not received due attention thus far, most likely because of technical difficulties in collecting sufficient intracardiac flow data in a safe manner. Here, we circumvent such obstacles by employing 4D STIC ultrasound scans to quantify the fetal heart motion in three normal 20-week fetuses, subsequently performing 3D computational fluid dynamics simulations on the left ventricles based on these patient-specific heart movements. Analysis of the simulation results shows that there are significant differences between fetal and adult ventricular blood flows which arise because of dissimilar heart morphology, E/A ratio, diastolic-systolic duration ratio, and heart rate. The formations of ventricular vortex rings were observed for both E- and A-wave in the flow simulations. These vortices had sufficient momentum to last until the end of diastole and were responsible for generating significant wall shear stresses on the myocardial endothelium, as well as helicity in systolic outflow. Based on findings from previous studies, we hypothesized that these vortex-induced flow properties play an important role in sustaining the efficiency of diastolic filling, systolic pumping, and cardiovascular flow in normal fetal hearts.

Effect of the positioning of a balloon valve in the aorta on coronary flow during aortic regurgitation.

PubMed

Antonatos, P G; Anthopoulos, L P; Kandyla, D D; Karras, A D; Moulopoulos, S D

1984-07-01

The coronary artery flow changes relative to the function of a catheter-mounted balloon valve used for relief of aortic regurgitation were studied in 10 mongrel dogs. Acute aortic regurgitation was produced by severing the aortic cusps with a long needle. Coronary flow was recorded from the left anterior descending coronary artery through an electromagnetic flowmeter. When the balloon was functioning within the cavity of the left ventricle there were no significant changes in the coronary flow and aortic pressure, except for a slight decrease in the aortic end-diastolic pressure. When it was functioning in the aortic ring the coronary flow increased 6.52 +/- 1.65 ml/min/100 gm of myocardium (p less than 0.001) and became predominantly diastolic. When it was functioning in the ascending aorta the coronary flow decreased 6.22 +/- 1.16 ml/min/100 gm of myocardium (p less than 0.001) and remained predominantly systolic. Finally, when the balloon was functioning in the thoracic aorta the coronary flow did not change significantly. With the balloon functioning in the aortic ring, ascending aorta, or thoracic aorta, there was a significant increase in the aortic end-diastolic pressure and decrease in the pulse pressure distal to the location of the balloon. It is concluded that the location of the balloon valve inserted for relief of aortic regurgitation influences the effect on coronary arterial flow.

Effects of systolic anterior motion of the mitral valve on haemodynamics. Evaluation by a direct method.

PubMed

Kaku, T; Sakurai, S; Furuno, Y; Yashiro, A; Nakashima, Y; Kuroiwa, A

1995-08-01

We evaluated the effects of systolic anterior motion systolic anterior motion of the mitral valve on cardiac haemodynamics. Seven adult mongrel dogs in which systolic anterior motion-septal contact was observed after dobutamine administration were used. To exclude the effects of left ventricular function and morphology, a stone removal basket catheter was placed in the left ventricular outflow tract, and haemodynamics were compared with the basket closed and opened. The basket was opened five times in three dogs not showing systolic anterior motion-septal contact, but the basket itself did not effect the haemodynamics. In the seven dogs that showed systolic anterior motion-septal contact without left ventricular hypertrophy, the basket was opened a total of 33 times in the presence of various degrees of systolic anterior motion-septal contact. After opening the basket, systolic anterior motion was reduced echocardiographically, and significant (P<0.01) changes were observed in the left ventricle-aorta pressure gradient (from 68 +/- 22 to 25 +/- 15 mm Hg), the systolic ejection period (from 146 +/- 19 to 135 +/- 16 ms), and the stroke volume (SV; from 9.4 +/- 2.9 to 10.1 +/- 3.3 ml). After basket inflation, aortic pressure and aortic flow waveforms changed but the peak pressure and flow velocity did not. The temporal distribution of left ventricular ejection also definitely changed after the basket was opened. No changes were observed in the peak dp/dt, peak negative dp/dt, time constant, left ventricular end-diastolic pressure, or left atrial pressure. These observations in this animal model of systolic anterior motion without left ventricular hypertrophy suggest that: (1) there is no potential for generation of an intra-cavity gradient in the absence of systolic anterior motion of the mitral valve, so that (2) systolic anterior motion narrowed the left ventricular outflow tract and, consequently, produced the systolic ejection period, and affected the left ventricular ejection dynamics, and that (3) the basket catheter is useful because it allows these assessments in the same heart with a nearly fixed left ventricular contractility, at least in our animal model.

Long-term follow-up after deferral of coronary intervention based on myocardial fractional flow reserve measurement.

PubMed

Mates, Martin; Hrabos, Vladimir; Hajek, Petr; Rataj, Ondrej; Vojacek, Jan

2005-05-01

To assess long-term results after deferring coronary intervention (percutaneous coronary intervention (PCI)) of an intermediate lesion with a value of myocardial fractional flow reserve (FFR) > or = 0.75 in a 'real life' patient population with no respect to results of stress tests (if performed) or coronary disease extent. PCI of an intermediate lesion was deferred in a group of 85 consecutive patients (54 men, 61+/-10 years) on the basis of the result of FFR > or = 0.75 (mean FFR, 0.89+/-0.06%). FFR was measured in 111 stenoses (mean diameter stenosis, 54+/-8%, left anterior descending coronary artery, 65 (58%), left circumflex coronary artery, 24 (22%), right coronary artery, 22 (20%). Multi-vessel disease (defined as visually assessed diameter reduction of more than 50% in at least two arteries of more than 1.5 mm diameter, supplying at least two of the three major coronary artery perfusion territories) was present in 67% of patients (one-vessel disease, 28 patients (33%), two-vessel disease, 39 patients (46%), three-vessel disease, 18 patients (21%). Recorded events during follow-up were as follows: all-cause death, cardiac death, non-fatal myocardial infarction, ischemia-driven target lesion transcatheter revascularization (TLR) and coronary artery bypass graft (CABG). Angina class (Canadian Cardiovascular Society (CCS) classification) and the need for anti-anginal drugs were recorded. Follow-up was completed in 85 patients (100%). Mean duration of follow-up was 22.6+/-6.6 months (range 4-33 months). Events occurred in 11 patients (13%). Seven patients died; this included two cardiac deaths. A non-fatal myocardial infarction occurred in one patient, one patient needed TLR and three patients underwent CABG. Estimated 33 month cardiac-event-free survival (Kaplan-Meier) was 91+/-4%. Angina class decreased [1.6+/-1.2 compared with 0.8+/-0.8 (P < 0.0001)] without difference with respect to the use of anti-anginal drugs (1.7+/-0.8 compared with 1.7+/-0.9, P = NS). Deferring coronary interventions of intermediate stenosis based on FFR measurement is safe with respect to long-term follow-up, irrespective of the extent of coronary artery disease.

[Selective left mainstem bronchial intubation in the neonatal intensive care unit].

PubMed

Ho, Anthony M H; Flavin, Michael P; Fleming, Melinda L; Mizubuti, Glenio Bitencourt

Selective neonatal left mainstem bronchial intubation to treat right lung disease is typically achieved with elaborate maneuvers, instrumentation and devices. This is often attributed to bronchial geometry which favors right mainstem entry of an endotracheal tube deliberately advanced beyond the carina. A neonate with severe bullous emphysema affecting the right lung required urgent non-ventilation of that lung. We achieved left mainstem bronchial intubation by turning the endotracheal tube 180° such that the Murphy's eye faced the left instead of the right, and simulated a left-handed intubation by slightly orientating the endotracheal tube such that its concavity faced the left instead of the right as in a conventional right-handed intubation. Urgent intubation of the left mainstem bronchus with an endotracheal tube can be easily achieved by recognizing that it is the position of the endotracheal tube tip and the direction of its concavity that are the chief determinants of which bronchus an endotracheal tube goes when advanced. This is important in critically ill neonates as the margin of safety and time window are small, and the absence of double-lumen tubes. Use of fiberoptic bronchoscope and blockers should be reserved as backup plans. Copyright © 2017 Sociedade Brasileira de Anestesiologia. Publicado por Elsevier Editora Ltda. All rights reserved.

ALCAPA and massive pulmonary atelectasis: how a stent in the airway can be life-saving.

PubMed

Serio, Paola; Chiappa, Enrico; Fainardi, Valentina; Favilli, Silvia; Murzi, Bruno; Baggi, Roberto; Arcieri, Luigi; Leone, Roberto; Mirabile, Lorenzo

2014-11-01

Anomalous left coronary artery from pulmonary artery (ALCAPA) is a rare congenital anomaly in which left coronary artery arises from the pulmonary artery resulting in progressive myocardial ischemia and dysfunction of the left ventricle. We report a case of ALCAPA with severe cardiac and respiratory failure and huge heart dilation compressing the left main bronchus and preventing from an effective ventilation. Emergency bronchial stenting allowed to improve left lung atelectasis, reduce pulmonary hypertension, resume anterograde left coronary artery perfusion and stabilize cardiovascular conditions to undertake a successful surgical correction. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Decreased cerebral perfusion in Duchenne muscular dystrophy patients.

PubMed

Doorenweerd, Nathalie; Dumas, Eve M; Ghariq, Eidrees; Schmid, Sophie; Straathof, Chiara S M; Roest, Arno A W; Wokke, Beatrijs H; van Zwet, Erik W; Webb, Andrew G; Hendriksen, Jos G M; van Buchem, Mark A; Verschuuren, Jan J G M; Asllani, Iris; Niks, Erik H; van Osch, Matthias J P; Kan, Hermien E

2017-01-01

Duchenne muscular dystrophy is caused by dystrophin gene mutations which lead to the absence of the protein dystrophin. A significant proportion of patients suffer from learning and behavioural disabilities, in addition to muscle weakness. We have previously shown that these patients have a smaller total brain and grey matter volume, and altered white matter microstructure compared to healthy controls. Patients with more distal gene mutations, predicted to affect dystrophin isoforms Dp140 and Dp427, showed greater grey matter reduction. Now, we studied if cerebral blood flow in Duchenne muscular dystrophy patients is altered, since cerebral expression of dystrophin also occurs in vascular endothelial cells and astrocytes associated with cerebral vasculature. T1-weighted anatomical and pseudo-continuous arterial spin labeling cerebral blood flow images were obtained from 26 patients and 19 age-matched controls (ages 8-18 years) on a 3 tesla MRI scanner. Group comparisons of cerebral blood flow were made with and without correcting for grey matter volume using partial volume correction. Results showed that patients had a lower cerebral blood flow than controls (40.0 ± 6.4 and 47.8 ± 6.3 mL/100 g/min respectively, p = 0.0002). This reduction was independent of grey matter volume, suggesting that they are two different aspects of the pathophysiology. Cerebral blood flow was lowest in patients lacking Dp140. There was no difference in CBF between ambulant and non-ambulant patients. Only three patients showed a reduced left ventricular ejection fraction. No correlation between cerebral blood flow and age was found. Our results indicate that cerebral perfusion is reduced in Duchenne muscular dystrophy patients independent of the reduced grey matter volume. Copyright © 2016 Elsevier B.V. All rights reserved.

Evaluation of cerebral blood flow changes in focal cerebral ischemia rats by using transcranial Doppler ultrasonography.

PubMed

Li, Le; Ke, Zheng; Tong, Kai Yu; Ying, Michael

2010-04-01

Ischemic stroke is typically characterized by the disruption of cerebral blood flow. This study aimed to consecutively evaluate the cerebral blood flow changes in a focal ischemia rat model during the occlusion-reperfusion procedure and along the recovery stage after stroke. In 12 Sprague Dawley (SD) rats, a middle cerebral artery occlusion/reperfusion (MCAo/r) surgery was conducted, which combines a permanent occlusion of the right common carotid artery (CCA), external carotid artery (ECA) and a transient occlusion of the right internal carotid artery (ICA) and middle cerebral artery (MCA) with a monofilament introduced from the proximal ICA towards the distal right ICA then removed after 90 min. Blood flow velocity (BFV) from the concerned arteries were measured using ultrasonography (13-4 MHz) at the basal stage before the surgery, after the reperfusion stage and during the post-stroke status. At reperfusion stage and after, BFV increased significantly in the left ICA and in the basilar artery (BA) (starting from post-24 h, p < 0.05 vs. basal). Moreover, BFV were reversed in the distal right ICA and reflow was recorded in the right MCA. Time-average maximum BFV in the right MCA at reperfusion and post-stroke 24-96 h was decreased significantly (p < 0.05 vs. basal). The reversed flow in the right ICA was enabled by the settlement of the collateral supply through the circle of Willis which consisted in higher BFV in the opposite ICA and in the BA still 24 h, although the proximal right ICA remain occluded. Ultrasound measurement of BFV helps to provide information on the redistribution of the blood flow supply after the onset of stroke. Copyright 2010 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Evaluation of Aortic Blood Flow and Wall Shear Stress in Aortic Stenosis and Its Association With Left Ventricular Remodeling

PubMed Central

von Knobelsdorff-Brenkenhoff, Florian; Karunaharamoorthy, Achudhan; Trauzeddel, Ralf Felix; Barker, Alex J; Blaszczyk, Edyta; Markl, Michael; Schulz-Menger, Jeanette

2016-01-01

Background Aortic stenosis (AS) leads to variable stress for the left ventricle (LV) and consequently a broad range of LV remodeling. Study aim was to describe blood flow patterns in the ascending aorta of AS patients and determine their association with remodeling. Methods and Results Thirty-seven patients with AS (14 mild, 8 moderate, 15 severe; age 63±13 years) and 37 healthy controls (age 60±10 years) underwent 4D-flow MRI. Helical and vortical flow formations and flow eccentricity were assessed in the ascending aorta. Normalized flow displacement from the vessel center and peak systolic wall shear stress (WSSpeak) in the ascending aorta were quantified. LV remodeling was assessed based on LV mass index (LVMI-I) and the ratio of LV mass to enddiastolic volume (relative wall mass; RWM). Marked helical and vortical flow formation and eccentricity were more prevalent in patients with AS than in healthy subjects, and AS patients exhibited an asymmetric and elevated distribution of WSSpeak. In AS, aortic orifice area was strongly negatively associated with vortical flow formation (p=0.0274), eccentricity (p=0.0070) and flow displacement (p=0.0021). Bicuspid aortic valve was associated with more intense helical (p=0.0098) and vortical flow formation (p=0.0536), higher flow displacement (p=0.11) and higher WSSpeak (p=0.0926). LVM-I and RWM were significantly associated with aortic orifice area (p=0.0611, p=0.0058) and flow displacement (p=0.0058, p=0.0283). Conclusions In this pilot study, AS leads to abnormal blood flow pattern and WSSpeak in the ascending aorta. In addition to aortic orifice area, normalized flow displacement was significantly associated with LV remodeling. PMID:26917824

Predicting changes in flow category in patients with severe aortic stenosis and preserved left ventricular ejection fraction on medical therapy.

PubMed

Ngiam, Jinghao Nicholas; Kuntjoro, Ivandito; Tan, Benjamin Y Q; Sim, Hui-Wen; Kong, William K F; Yeo, Tiong-Cheng; Poh, Kian-Keong

2017-11-01

Controversy surrounds the prognosis and management of patients with paradoxical low-flow severe aortic stenosis (AS) with preserved left ventricular ejection fraction (LVEF). It was not certain if patients in a particular flow category remained in the same category as disease progressed. We investigated whether there were switches in categories and if so, their predictors. Consecutive subjects (n = 203) with isolated severe AS and paired echocardiography (>180 days apart) were studied. They were divided into 4 groups, based on their flow categories and if they progressed on subsequent echocardiography to switch or remain in the same flow category. Univariate analyses of clinical and echocardiographic parameters identified predictors of these changes in flow category. One hundred eighteen were normal flow (SVI ≥ 35 mL/m 2 ), while 85 were low flow on index echocardiography. In the patients with normal flow, 33% switched to low flow. This was associated with higher valvuloarterial impedance (Zva, P < .001) and lower systemic arterial compliance (SAC, P < .001) compared to index echocardiography, and predicted by higher initial Zva (optimized cutoff >4.77 mm Hg/mL/m 2 , AUC = 0.81 [95% CI:0.75-0.87, P < .001]). In patients with low flow, 25% switched to normal flow, which was associated with lower Zva and higher SAC and the switch was predicted by a higher initial mean transaortic pressure gradient. A significant number of patients switched flow categories in severe AS with preserved LVEF on subsequent echocardiography. Changes in flow were reflected by respective changes in Zva and SAC. Identifying echocardiographic predictors of a switch in category may guide prognostication and management of such patients. © 2017, Wiley Periodicals, Inc.

Assessment of stent edge dissections by fractional flow reserve.

PubMed

Chung, Ju-Hyun; Ann, Soe Hee; Koo, Bon-Kwon; Nam, Chang-Wook; Doh, Joon-Hyung; Singh, Gillian Balbir; Kim, Hyung Il; Shin, Eun-Seok

2015-04-15

Edge dissections after intervention have been studied with imaging techniques, however, functional assessment has not been studied yet. We investigated the relationship between fractional flow reserve (FFR) and the angiographic type of stent edge dissections and tried to assess the use of FFR-guided management for edge dissection. 51 edge dissections assessed by FFR were included in this prospective observational study. FFR was measured for each type of edge dissection and compared with quantitative coronary angiographic findings. Clinical outcomes were evaluated based on FFR measurements. Edge dissections were classified as type A (47.1%; 24/51), type B (41.2%; 21/51), type C (2.0%; 1/51) and type D (9.8%; 5/51). Mean FFR in type A dissection was 0.87 ± 0.09, in type B 0.86 ± 0.07, in type C 0.72 and in type D 0.57 ± 0.08. All type C and D dissections (6/51) had FFR ≤ 0.8 and were treated with additional stents. Among the 45 type A and B dissections, 8 had a FFR ≤ 0.8 (17.8%), and 50% received additional stenting. All dissections with FFR >0.8 were left untreated except one long dissection case. There was no death, myocardial infarction or target lesion revascularization during hospitalization or the follow-up period (median 152 days; IQR 42-352 days). FFR correlates well with an angiographic type of edge dissection. Angiographic findings are sufficient for deciding the treatment of severe dissections such as types C and D, while FFR-guided management may be safe and effective for mild edge dissections such as types A and B. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Estimation of infarct size using transthoracic Doppler echocardiographic measurement of coronary flow reserve in infarct related and reference coronary artery.

PubMed

Giga, Vojislav; Dobric, Milan; Beleslin, Branko; Sobic-Saranovic, Dragana; Tesic, Milorad; Djordjevic-Dikic, Ana; Stepanovic, Jelena; Nedeljkovic, Ivana; Artiko, Vera; Obradovic, Vladimir; Seferovic, Petar M; Ostojic, Miodrag

2013-09-20

Patients in chronic phase of myocardial infarction (MI) have decreased coronary flow reserve (CFR) in infarct related artery (IRA) that is proportional to the extent of microvascular/myocardial damage. We proposed a novel model for the assessment of microvascular damage and infarct size using Doppler echocardiography evaluation of CFRs of the IRA (LAD) and reference artery (RCA). Our study included 34 consecutive patients (28 men, mean age 50 ± 11 years) with first anterior STEMI and single vessel disease successfully treated with primary PCI. All patients underwent SPECT MPI for the assessment of infarct size (expressed as a percentage of myocardium with fixed perfusion abnormalities) and CFR evaluation of LAD and RCA. CFR derived percentage of microvascular damage (CFR PMD) was calculated as: CFR PMD=(CFR RCA-CFR LAD)/(CFR RCA-1)×100 (%). CFR PMD correlated significantly with all parameters evaluating the severity of myocardial damage including: peak CK activity (r=0.632, p<0.001), WMSI (r=0.857, p<0.001), ejection fraction (r=-0.820, p<0.001), left ventricular end diastolic (r=0.757, p<0.001) and end systolic volume (r=0.794, p<0.001). Most importantly, CFR PMD (22 ± 17%) correlated significantly with infarct size by SPECT MPI (21 ± 17%) (r=0.874, p<0.001). CFR PMD derived from the proposed model was significantly related to echocardiographic and enzymatic parameters of infarct size, as well as to myocardial damage assessed by SPECT MPI in patients with successfully reperfused first anterior STEMI. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Signing and pavement marking for concurrent-flow high-occupancy-vehicle lanes : summary of current practice

DOT National Transportation Integrated Search

1997-01-01

Concurrent-flow lanes account for more than half of existing high-occupancy-vehicle (HOV) mileage in the United States. Traffic on this type of HOV lane operates in the same direction as the adjacent traffic, typically in the far-left lane. Limited n...

Boeing engineers perform air flow balance testing.

NASA Image and Video Library

2017-10-05

Boeing engineers, Chris Chapman, left, Greg Clark, center, and Ashesh Patel, right, perform air flow balance testing on NASA's new Basic Express Racks. The racks, developed at Marshall, will expand the capabilities for science research aboard the International Space Station. Delivery to the station is scheduled for late 2018.

Diastolic coronary artery pressure-flow velocity relationships in conscious man.

PubMed

Dole, W P; Richards, K L; Hartley, C J; Alexander, G M; Campbell, A B; Bishop, V S

1984-09-01

We characterised the diastolic pressure-flow velocity relationship in the normal left coronary artery of conscious man before and after vasodilatation with angiographic contrast medium. Phasic coronary artery pressure and flow velocity were measured in ten patients during individual diastoles (0.5 to 1.0 s) using a 20 MHz catheter-tipped, pulsed Doppler transducer. All pressure-flow velocity curves were linear over the diastolic pressure range of 110 +/- 15 (SD) mmHg to 71 +/- 7 mmHg (r = 0.97 +/- 0.01). In the basal state, values for slope and extrapolated zero flow pressure intercept averaged 0.35 +/- 0.12 cm X s-1 X mmHg-1 and 51.7 +/- 8.6 mmHg, respectively. Vasodilatation resulted in a 2.5 +/- 0.5 fold increase in mean flow velocity. The diastolic pressure-flow velocity relationship obtained during peak vasodilatation compared to that during basal conditions was characterised by a steeper slope (0.80 +/- 0.48 cm X s-1 X mmHg-1, p less than 0.001) and lower extrapolated zero flow pressure intercept (37.9 +/- 9.8 mmHg, p less than 0.05). Mean right atrial pressure for the group averaged 4.4 +/- 1.7 mmHg, while left ventricular end-diastolic pressure averaged 8.7 +/- 2.8 mmHg. These observations in man are similar to data reported in the canine coronary circulation which are consistent with a vascular waterfall model of diastolic flow regulation. In this model, coronary blood flow may be regulated by changes in diastolic zero flow pressure as well as in coronary resistance.

Management of Post-Traumatic Phlegmasia Cerulea Dolens via Right-to-Left Femoral Vein to Femoral Vein Bypass (Palma Procedure).

PubMed

Dua, Anahita; Heller, Jennifer; Lee, Cheong

2017-11-01

Phlegmasia cerulea dolens (PCD) is a rare condition resulting from venous occlusion that impairs arterial flow. We report a rare case of post-traumatic PCD after ligation of the iliac vein with successful treatment by right-to-left femoral vein to femoral vein bypass using left great saphenous vein (Palma procedure). The clinical presentation, diagnostic process, and approach to management along with a literature review on the operative management of PCD are presented in this case report.

Experimental study on the effect of an artificial cardiac valve on the left ventricular flow

NASA Astrophysics Data System (ADS)

Wang, JiangSheng; Gao, Qi; Wei, RunJie; Wang, JinJun

2017-09-01

The use of artificial valves to replace diseased human heart valves is currently the main solution to address the malfunctioning of these valves. However, the effect of artificial valves on the ventricular flow still needs to be understood in flow physics. The left ventricular flow downstream of a St. Jude Medical (SJM) bileaflet mechanical heart valve (BMHV), which is a widely implanted mechanical bileaflet valve, is investigated with time-resolved particle image velocimetry in the current work. A tilting-disk valve is installed on the aortic orifice to guarantee unidirectional flow. Several post-processing tools are applied to provide combined analyses of the physics involved in the ventricular flow. The triple jet pattern that is closely related to the characteristics of the bileaflet valve is discussed in detail from both Eulerian and Lagrangian views. The effects of large-scale vortices on the transportation of blood are revealed by the combined analysis of the tracking of Lagrangian coherent structures, the Eulerian monitoring of the shear stresses, and virtual dye visualization. It is found that the utilization of the SJM BMHV complicates the ventricular flow and could reduce the efficiency of blood transportation. In addition, the kinematics of the bileaflets is presented to explore the effects of flow structures on their motion. These combined analyses could elucidate the properties of SJM BMHV. Furthermore, they could provide new insights into the understanding of other complex blood flows.

Patent ductus arteriosus associated with congenital anomaly of coronary artery.

PubMed

Maleki, Majid; Azizian, Nassrin; Esmaeilzadeh, Maryam; Moradi, Bahieh

2013-11-01

We reported a case of patent ductus arteriosus (PDA) with congenital anomaly of coronary arteries as abnormal origin of right coronary artery (RCA) and left coronary artery (LCA) from a single ostium of the right coronary sinus. A 21-year-old man referred to our institution for evaluation of cardiac murmur. He has suffered from palpitation and atypical chest pain for three months. On physical examination, a continuous murmur was heard in the second left parasternal space. Transthoracic echocardiography showed normal left and right ventricular size and systolic function (LVEF = 55%). Main pulmonary artery (PA) and left pulmonary artery (LPA) branch were considerably dilated. Considering normal coronary flow, lack of clinical evidence of myocardial ischemia and echocardiography findings, patient underwent surgical closure of PDA via left thoracotomy and after five days discharged uneventfully.

Left globus pallidus abnormality in never-medicated patients with schizophrenia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Early, T.S.; Reiman, E.M.; Raichle, M.E.

1987-01-01

Schizophrenia is a severe psychiatric disorder characterized by onset in young adulthood, the occurrence of hallucinations and delusions, and the development of enduring psychosocial disability. The pathophysiology of this disorder remains unknown. Studies of cerebral blood flow and metabolism designed to identify brain abnormalities in schizophrenia have been limited by inadequate methods of anatomical localization and the possibility of persistent medication effects. The authors have now used positron emission tomography and a validated method of anatomical localization in an attempt to identify abnormalities of regional cerebral blood flow in newly diagnosed never-medicated patients with schizophrenia. An exploratory study of 5more » patients and 10 normal control subjects identified abnormally high blood flow in the left globus pallidus of patients with schizophrenia. A replication study of 5 additional patients and 10 additional control subjects confirmed this finding. No other abnormalities were found.« less

Experimental and simulation studies on the effect of suction opening orientation on solar vertical chimney

NASA Astrophysics Data System (ADS)

Kumar, L. Madan Ananda; Sivaramakrishnan, V.; Premalatha, M.; Vivekanandan, M.

2017-07-01

The zero energy building considered is a single storey building in Tiruchirappalli city retrofitted with various green features. This study investigated the effect of a suction opening orientation on a vertical solar chimney (VSC), integrated into a one-storey building. It was designed, manufactured and tested through selection of different suction openings for the entry of air, including right, left, front, back, both right and left and both front and back sides. Genetic algorithm (GA) calculates maximum air flow rate for a building with VSC for better suction opening, in Tiruchirappalli's dry, environmental conditions. GA is a useful technique for finding an improved suction opening specifically in the presence of a host of independent parameters which are large. The obtained results are related to fluid flow temperature distribution along the chimney, mass flow rate and air change per hour. The findings between the GA and the experimental results show sound agreement.

The Role of Diagrammatic Respresentation in Learning Sequences, Identification and Classification as a Function of Verbal and Spatial Ability.

ERIC Educational Resources Information Center

Winn, William

1982-01-01

Results of this study suggest that diagrams provide different types of information for ninth-grade students (N=273) and that learners process each type differently. Flow diagrams running across a page from either left to right or right to left, or with or without drawings of dinosaurs, were used. (JN)

Training-induced brain plasticity in aphasia.

PubMed

Musso, M; Weiller, C; Kiebel, S; Müller, S P; Bülau, P; Rijntjes, M

1999-09-01

It has long been a matter of debate whether recovery from aphasia after left perisylvian lesions is mediated by the preserved left hemispheric language zones or by the homologous right hemisphere regions. Using PET, we investigated the short-term changes in the cortical network involved in language comprehension during recovery from aphasia. In 12 consecutive measurements of regional cerebral blood flow (rCBF), four patients with Wernicke's aphasia, caused by a posterior left middle cerebral artery infarction, were tested with a language comprehension task. Comprehension was estimated directly after each scan with a modified version of the Token Test. In the interval between the scans, the patients participated in brief, intense language comprehension training. A significant improvement in performance was observed in all patients. We correlated changes in blood flow measured during the language comprehension task with the scores achieved in the Token Test. The regions which best correlated with the training-induced improvement in verbal comprehension were the posterior part of the right superior temporal gyrus and the left precuneus. This study supports the role of the right hemisphere in recovery from aphasia and demonstrates that the improvement in auditory comprehension induced by specific training is associated with functional brain reorganization.

Tbx6 controls left-right asymmetry through regulation of Gdf1.

PubMed

Concepcion, Daniel; Hamada, Hiroshi; Papaioannou, Virginia E

2018-05-04

The Tbx6 transcription factor plays multiple roles during gastrulation, somite formation and body axis determination. One of the notable features of the Tbx6 homozygous mutant phenotype is randomization of left/right axis determination. Cilia of the node are morphologically abnormal, leading to the hypothesis that disrupted nodal flow is the cause of the laterality defect. However, Tbx6 is expressed around but not in the node, leading to uncertainty as to the mechanism of this effect. In this study, we have examined the molecular characteristics of the node and the genetic cascade determining left/right axis determination. We found evidence that a leftward nodal flow is generated in Tbx6 homozygous mutants despite the cilia defect, establishing the initial asymmetric gene expression in Dand5 around the node, but that the transduction of the signal from the node to the left lateral plate mesoderm is disrupted due to lack of expression of the Nodal coligand Gdf1 around the node. Gdf1 was shown to be a downstream target of Tbx6 and a Gdf1 transgene partially rescues the laterality defect. © 2018. Published by The Company of Biologists Ltd.

Lateralization of cerebral blood flow velocity changes during auditory stimulation: a functional transcranial Doppler study.

PubMed

Carod Artal, Francisco Javier; Vázquez Cabrera, Carolina; Horan, Thomas Anthony

2004-01-01

Transcranial Doppler ultrasonography (TCD) permits the assessment of cognitively induced cerebral blood flow velocity (BFV) changes. We sought to investigate the lateralization of BFV acceleration induced by auditory stimulation and speech in a normal population. TCD monitoring of BFV in the middle cerebral arteries (MCA) was performed in 30 normal right-handed volunteers (average age = 31.7 years). Noise stimulation, speech, and instrumental music were administered during 60 sec to both ears by means of earphones. Auditory stimulation induced a significant BFV increase in the ipsilateral MCA compared to BFV during the preceding rest periods. Left MCA BFV increased by an average of 7.1% (noise), 8.4% (language), and 5.2% (melody) over baseline values, and right MCA BFV increased 5.1%, 3.1%, and 4.2%, respectively. Speech stimulation produced a significant increase in BFV in the left hemisphere MCA (from 49.86 to 54.03 cm/sec; p < .0001). Left MCA BFV response to speech stimulation may reflect the dominance of the left hemisphere in language processing by right-handed individuals. Due to the high temporal resolution of TCD we were able show a habituation effect during the 60-sec stimulation period.

Transcranial doppler in sickle cell anaemia: evaluation of brain blood flow parameters in children of Aracaju, Northeast-Brazil.

PubMed

Melo, Hyder Aragão de; Barreto-Filho, José Augusto S; Prado, Roberto César P do; Cipolotti, Rosana

2008-06-01

Environmental factors interfere on sickle cell anaemia (SCA). Transcanial Doppler (TCD) is important to evaluate cerebrovascular disease. To evaluate brain haemodynamic profile of children with SCA in Sergipe. Cross sectional study (group1: SCA patients aged 3-18; group2: age and sex matched healthy individuals). Baseline brain flow was evaluated. Group1=34 patients; group 2=81 controls. SCA patients had mean velocity (MV)=125.69 cm/s+/-23.40; pulsatility index (PI)=0.66+/-0.10; middle cerebral artery ratio (MCAr)=14.53+/-15.23; right anterior cerebral artery/right middle cerebral artery=0.77+/-0.20; left anterior cerebral artery/left middle cerebral artery=0.78+/-0.20. Controls had MV=79.44+/-15.54; PI=0.82+/-0.11; MCAr=13.19+/-13.77; right anterior cerebral artery/right middle cerebral artery=0.80+/-0.16; left anterior cerebral artery/left middle cerebral artery=0.84+/-0.18. MV and PI differences were statistically significant between groups. MV was related to age but not to gender. MV evaluation using TCD was similar to international standards and possible to be used in our setting.

Changes in cerebral blood flow after cognitive behavior therapy in patients with panic disorder: a SPECT study

PubMed Central

Seo, Ho-Jun; Choi, Young Hee; Chung, Yong-An; Rho, Wangku; Chae, Jeong-Ho

2014-01-01

Aim Inconsistent results continue to be reported in studies that examine the neural correlates of cognitive behavioral therapy (CBT) in patients with panic disorder. We examined the changes in regional cerebral blood flow (rCBF) associated with the alleviation of anxiety by CBT in panic patients. Methods The change in rCBF and clinical symptoms before and after CBT were assessed using single photon emission computed tomography and various clinical measures were analyzed. Results Fourteen subjects who completed CBT showed significant improvements in symptoms on clinical measures, including the Panic and Agoraphobic Scale and the Anxiety Sensitivity Index-Revised. After CBT, increased rCBF was detected in the left postcentral gyrus (BA 43), left precentral gyrus (BA 4), and left inferior frontal gyrus (BA 9 and BA 47), whereas decreased rCBF was detected in the left pons. Correlation analysis of the association between the changes in rCBF and changes in each clinical measure did not show significant results. Conclusion We found changes in the rCBF associated with the successful completion of CBT. The present findings may help clarify the effects of CBT on changes in brain activity in panic disorder. PMID:24790449

Implications of persistent prehypertension for ageing-related changes in left ventricular geometry and function: the MONICA/KORA Augsburg study.

PubMed

Markus, Marcello Ricardo Paulista; Stritzke, Jan; Lieb, Wolfgang; Mayer, Björn; Luchner, Andreas; Döring, Angela; Keil, Ulrich; Hense, Hans-Werner; Schunkert, Heribert

2008-10-01

It is unclear whether persistent prehypertension causes structural or functional alterations of the heart. We examined echocardiographic data of 1005 adults from a population-based survey at baseline in 1994/1995 and at follow-up in 2004/2005. We compared individuals who had either persistently normal (<120 mmHg systolic and <80 mmHg diastolic, n = 142) or prehypertensive blood pressure (120-139 mmHg or 80-89 mmHg, n = 119) at both examinations using multivariate regression modeling. Over 10 years, left ventricular end-diastolic diameters were stable and did not differ between the two groups. However, the prehypertensive blood pressure group displayed more pronounced ageing-related increases of left ventricular wall thickness (+4.7 versus +11.9%, P < 0.001) and left ventricular mass (+8.6 versus +15.7%, P = 0.006). Prehypertension was associated with a raised incidence of left ventricular concentric remodeling (adjusted odds ratio 10.7, 95% confidence interval 2.82-40.4) and left ventricular hypertrophy (adjusted odds ratio 5.33, 1.58-17.9). The ratio of early and late diastolic peak transmitral flow velocities (E/A) decreased by 7.7% in the normal blood pressure versus 15.7% in the prehypertensive blood pressure group (P = 0.003) and at follow-up the ratio of early diastolic peak transmitral flow and early diastolic peak myocardial relaxation velocities (E/EM) was higher (9.1 versus 8.5, P = 0.031) and left atrial size was larger (36.5 versus 35.3 mm, P = 0.024) in the prehypertensive blood pressure group. Finally, the adjusted odds ratio for incident diastolic dysfunction was 2.52 (1.01-6.31) for the prehypertensive blood pressure group. Persistent prehypertension accelerates the development of hypertrophy and diastolic dysfunction of the heart.

Myocardial Blood Flow Distribution during Ischemia-Induced Coronary Vasodilation in the Unanesthetized Dog

PubMed Central

Bache, Robert J.; Cobb, Frederick R.; Greenfield, Joseph C.

1974-01-01

This study was designed to determine whether coronary vasodilation distal to a flow-limiting coronary artery stenosis could result in redistribution of myocardial blood flow to produce subendocardial underperfusion. Studies were performed in 10 awake dogs chronically prepared with electromagnetic flow-meters and hydraulic occluders on the left circumflex coronary artery. Regional myocardial blood flow was measured using radionuclide-labeled microspheres, 7-10 μm in diameter, injected into the left atrium. A 5-s coronary artery occlusion was followed by reactive hyperemia with excess inflow of arterial blood effecting 375±20% repayment of the blood flow debt incurred during occlusion. When, after a 5-s occlusion, the occluder was only partially released to hold arterial inflow to the preocclusion level for 20 s before complete release, the delayed reactive hyperemia was augmented (mean blood flow repayment = 610±45%, P < 0.01). This augmentation of the reactive hyperemia suggested that ischemia was continuing during the interval of coronary vasodilation when coronary inflow was at the preocclusion level. Measurements of regional myocardial blood flow demonstrated that endocardial flow slightly exceeded epicardial flow during control conditions. When arterial inflow was limited to the preocclusion rate during vasodilation after a 5-s total coronary artery occlusion, however, flow to the subepicardial myocardium was increased at the expense of underperfusion of the subendocardial myocardium. Thus, in the presence of a flow-limiting proximal coronary artery stenosis, ischemia-induced coronary vasodilation resulted in redistribution of myocardial blood flow with production of subendocardial ischemia in the presence of a net volume of arterial inflow which, if properly distributed, would have been adequate to prevent myocardial ischemia. Images PMID:4279928

Does lung ischemia and reperfusion have an impact on coronary flow? A quantitative coronary blood-flow analysis with inflammatory cytokine profile†

PubMed Central

Karapanos, Nikolaos Tsirikos; Wettstein, Peter J.; Li, Zhuo; Huebner, Marianne; Park, Soon J.; Deschamps, Claude; Cassivi, Stephen D.

2012-01-01

OBJECTIVE Ischemia-reperfusion (IR) injury remains a major cause of early morbidity and mortality after lung transplantation with poorly documented extrapulmonary repercussions. To determine the hemodynamic effect due to lung IR injury, we performed a quantitative coronary blood-flow analysis in a swine model of in situ lung ischemia and reperfusion. METHODS In 14 healthy pigs, blood flow was measured in the ascending aorta, left anterior descending (LAD), circumflex (Cx), right coronary artery (RCA), right common carotid artery (RCCA), and left internal mammary artery (LIMA), along with left-and right-ventricular pressures (LVP and RVP), aortic pressure (AoP), and pulmonary artery pressure (PAP). Cardiac Troponin (cTn), interleukin 6 and 10 (IL-6 and IL-10), and tumor necrosis factor A (TNF-A) were measured in coronary sinus blood samples. The experimental (IR) group (n = 10) underwent 60 min of lung ischemia followed by 60 min of reperfusion by clamping and releasing the left pulmonary hilum. Simultaneous measurements of all parameters were made at baseline and during IR. The control group (n = 4) had similar measurements without lung IR. RESULTS In the IR group, total coronary flow (TCF = LAD + Cx + RCA blood-flow) decreased precipitously and significantly from baseline (113 ± 41 ml min”1) during IR (p < 0.05), with the lowest value observed at 60 min of reperfusion (-37.1%, p < 0.003). Baseline cTn (0.08 ± 0.02 ng ml−1) increased during IR and peaked at 45 min of reperfusion (+138%, p < 0.001). Baseline IL-6 (9.2 ± 2.17 pg ml−1) increased during IR and peaked at 60 min of reperfusion (+228%, p < 0.0001). Significant LVP drop at 5 min of ischemia ( p < 0.05) was followed by a slow return to baseline at 45 min of ischemia. A second LVP drop occurred at reperfusion ( p < 0.05) and persisted. Conversely, RVP increased throughout ischemia (p < 0.05) and returned toward baseline during reperfusion. Coronary blood flow and hemodynamic profile remained unchanged in the control group. IL-10 and TNF-A remained below the measurable range for both the groups. CONCLUSIONS In situ lung IR has a marked negative impact on coronary blood flow, hemodynamics, and inflammatory profile. In addition, to the best of our knowledge, this is the first study where coronary blood flow is directly measured during lung IR, revealing the associated increased cardiac risk. PMID:21900017

Single origin of right and left pulmonary arteries from ascending aorta with atretic main pulmonary artery from right ventricle and left pulmonary sling.

PubMed

Hsieh, Min-Ling; Huang, Li-Ting; Wang, Jieh-Neng; Tsai, Yi-Shan

2015-01-01

Either left pulmonary sling or single origin of right and left pulmonary arteries (only three cases reported previously) are rare congenital heart anomalies and concomitantly occurred had not been reported. The image presentation is similar to type A1 truncus arteriosus but preserved pulmonary valve and main pulmonary artery development. Copyright © 2015 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.

Heart Transplant in Patient With Isolated Left Superior Vena Cava by Atrial Appendage Rotation.

PubMed

Reyes, Karl M; Gupta, Dipankar; Fricker, Frederick Jay; Cooke, Susan; Bleiweis, Mark S

2018-06-01

Orthotopic heart transplantation in patients with an isolated persistent left superior vena cava is extremely rare, and the anastomotic connection between a right-sided donor superior vena cava and left-sided recipient superior vena cava can be challenging to perform. We present a novel technique used in an infant female, using the left atrial appendage to extend the superior vena cava anastomosis. Copyright © 2018 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Structural and functional brain changes in early- and mid-stage primary open-angle glaucoma using voxel-based morphometry and functional magnetic resonance imaging.

PubMed

Jiang, Ming-Ming; Zhou, Qing; Liu, Xiao-Yong; Shi, Chang-Zheng; Chen, Jian; Huang, Xiang-He

2017-03-01

To investigate structural and functional brain changes in patients with primary open-angle glaucoma (POAG) by using voxel-based morphometry based on diffeomorphic anatomical registration through exponentiated Lie algebra (VBM-DARTEL) and blood oxygenation level dependent functional magnetic resonance imaging (BOLD-fMRI), respectively.Thirteen patients diagnosed with POAG and 13 age- and sex-matched healthy controls were enrolled in the study. For each participant, high-resolution structural brain imaging and blood flow imaging were acquired on a 3.0-Tesla magnetic resonance imaging (MRI) scanner. Structural and functional changes between the POAG and control groups were analyzed. An analysis was carried out to identify correlations between structural and functional changes acquired in the previous analysis and the retinal nerve fiber layer (RNFL).Patients in the POAG group showed a significant (P < 0.001) volume increase in the midbrain, left brainstem, frontal gyrus, cerebellar vermis, left inferior parietal lobule, caudate nucleus, thalamus, precuneus, and Brodmann areas 7, 18, and 46. Moreover, significant (P < 0.001) BOLD signal changes were observed in the right supramarginal gyrus, frontal gyrus, superior frontal gyrus, left inferior parietal lobule, left cuneus, and left midcingulate area; many of these regions had high correlations with the RNFL.Patients with POAG undergo widespread and complex changes in cortical brain structure and blood flow. (ClinicalTrials.gov number: NCT02570867).

Percutaneous Repair of Postoperative Mitral Regurgitation After Left Ventricular Assist Device Implant.

PubMed

Cork, David P; Adamson, Robert; Gollapudi, Raghava; Dembitsky, Walter; Jaski, Brian

2018-02-01

Mitral regurgitation commonly improves after implantation of a left ventricular assist device without concomitant valvular repair owing to the mechanical unloading of the left ventricle. However, the development (or persistence) of significant mitral regurgitation after implantation of a left ventricular assist device is associated with adverse clinical events. We present a case of a left ventricular assist device patient who successfully underwent a percutaneous MitraClip procedure for repair of persistent late postoperative mitral insufficiency with demonstrable clinical and hemodynamic improvement. Copyright © 2018 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Volcanic Plains of Io Near Galai Patera

NASA Technical Reports Server (NTRS)

1983-01-01

Io's volcanic plains are shown in this Voyager 1 image, which spans an area about 1030 km (640 miles) from left to right. North is about the 1:30 position. Numerous volcanic calderas and lava flows are visible here. The brown teardrop-shaped feature at left center is Galai Patera, a 100-km-long (62 mi) lava-flooded caldera (collapsed vent) of a volcano. The composition of Io's volcanic plains and lava flows has not been determined. The prevalent yellow, brown, and orange material may consist dominantly of sulfur with surface frosts of sulfur dioxide or of silicates (such as basalt) encrusted with sulfur and sulfur dioxide condensates. The whitish patches probably are freshly deposited SO2 frost.

Wildfire-related debris-flow initiation processes, Storm King Mountain, Colorado

USGS Publications Warehouse

Cannon, S.H.; Kirkham, R.M.; Parise, M.

2001-01-01

A torrential rainstorm on September 1, 1994 at the recently burned hillslopes of Storm King Mountain, CO, resulted in the generation of debris flows from every burned drainage basin. Maps (1:5000 scale) of bedrock and surficial materials and of the debris-flow paths, coupled with a 10-m Digital Elevation Model (DEM) of topography, are used to evaluate the processes that generated fire-related debris flows in this setting. These evaluations form the basis for a descriptive model for fire-related debris-flow initiation. The prominent paths left by the debris flows originated in 0- and 1st-order hollows or channels. Discrete soil-slip scars do not occur at the heads of these paths. Although 58 soil-slip scars were mapped on hillslopes in the burned basins, material derived from these soil slips accounted for only about 7% of the total volume of material deposited at canyon mouths. This fact, combined with observations of significant erosion of hillslope materials, suggests that a runoff-dominated process of progressive sediment entrainment by surface runoff, rather than infiltration-triggered failure of discrete soil slips, was the primary mechanism of debris-flow initiation. A paucity of channel incision, along with observations of extensive hillslope erosion, indicates that a significant proportion of material in the debris flows was derived from the hillslopes, with a smaller contribution from the channels. Because of the importance of runoff-dominated rather than infiltration-dominated processes in the generation of these fire-related debris flows, the runoff-contributing area that extends upslope from the point of debris-flow initiation to the drainage divide, and its gradient, becomes a critical constraint in debris-flow initiation. Slope-area thresholds for fire-related debris-flow initiation from Storm King Mountain are defined by functions of the form Acr(tan ??)3 = S, where Acr is the critical area extending upslope from the initiation location to the drainage divide, and tan ?? is its gradient. The thresholds vary with different materials. ?? 2001 Elsevier Science B.V. All rights reserved.

Successful transcatheter occlusion of an anomalous pulmonary vein with dual drainage to the left atrium.

PubMed

Wilson, W; Horlick, E; Benson, L

2015-06-01

We describe a case of a scimitar syndrome "variant" where dual drainage existed from the right upper and middle pulmonary veins to the inferior vena cava and left atrium. Device closure of the anomalous vein at the level of the connection to the IVC was successful in achieving diversion of pulmonary venous flow to the left atrium. Vigilance during work-up of anomalous pulmonary venous drainage (whether isolated or associated with other cardiac defects that may be amenable to device closure) is important to define the presence of dual connections to the left atrium, in which case a less-invasive transcatheter approach may be feasible. © 2015 Wiley Periodicals, Inc.

Dynamic damping of the aortic pressure trace during hyperemia: the impact on fractional flow reserve measurement.

PubMed

Lockie, Tim; Rolandi, M Cristina; Piek, Jan J

2013-10-01

We report on two cases that illustrate an important caveat in the measurement of fractional flow reserve (FFR) in coronary arteries. To obtain accurate FFR measurements, two fundamental requirements must be fulfilled. One is to minimize microvascular resistance; the other is that there is no damping of the proximal aortic pressure trace. A problem with either of these requirements can be a source of serious error in the measurement of FFR. In each case we present here, despite a good aortic pressure trace at the start of the procedure, there is dynamic damping of the pressure trace during hyperemia, secondary to axial migration of the guiding catheter into the left main stem (LMS). In both cases, a normal aortic pressure trace (Pa) is present at baseline. After intracoronary adenosine injection, there was a fall in both mean Pa and distal coronary pressure (Pd) concomitant with damping of Pa, evidenced by loss of the dicrotic notch and ventricularization of the pressure trace. The resultant FFR value is underestimated. As hyperemia wears off, both pressure traces return to normal with good articulation of the dicrotic notch. When the procedure was repeated taking care to ensure that the guide did not move into the LMS during hyperemia, the Pa trace remained stable following intracoronary adenosine, while mean Pd decreased as before. In both cases, hemodynamically significant lesions were demonstrated that had been masked by the artifactual drop in Pa during the first attempt.

Three Dimensional Energetics of Left Ventricle Flows Using Time-Resolved DPIV

NASA Astrophysics Data System (ADS)

Pierrakos, Olga; Vlachos, Pavlos

2006-11-01

Left ventricular (LV) flows in the human heart are very complex and in the presence of unhealthy or prosthetic heart valves (HV), the complexity of the flow is further increased. Yet to date, no study has documented the complex 3D hemodynamic characteristics and energetics of LV flows. We present high sampling frequency Time Resolved DPIV results obtained in a flexible, transparent LV documenting the evolution of eddies and turbulence. The purpose is to characterize the energetics of the LV flow field in the presence of four orientations of the most commonly implanted mechanical bileaflet HV and a porcine valve. By decomposing the energy scales of the flow field, the ultimate goal is to quantify the total energy losses associated with vortex ring formation and turbulence dissipation. The energies associated to vortex ring formation give a measure of the energy trapped within the structure while estimations of the turbulence dissipation rate (TDR) give a measure of the energy dissipated at the smaller scales. For the first time in cardiovascular applications, an LES-based PIV method, which overcomes the limitations of conventional TDR estimation methods that assume homogeneous isotropic turbulence, was employed. We observed that energy lost at the larger scales (vortex ring) is much higher than the energy lost at the smaller scales due to turbulence dissipation.

Capacity Estimation Model for Signalized Intersections under the Impact of Access Point

PubMed Central

Zhao, Jing; Li, Peng; Zhou, Xizhao

2016-01-01

Highway Capacity Manual 2010 provides various factors to adjust the base saturation flow rate for the capacity analysis of signalized intersections. No factors, however, is considered for the potential change of signalized intersections capacity caused by the access point closeing to the signalized intersection. This paper presented a theoretical model to estimate the lane group capacity at signalized intersections with the consideration of the effects of access points. Two scenarios of access point locations, upstream or downstream of the signalized intersection, and impacts of six types of access traffic flow are taken into account. The proposed capacity model was validated based on VISSIM simulation. Results of extensive numerical analysis reveal the substantial impact of access point on the capacity, which has an inverse correlation with both the number of major street lanes and the distance between the intersection and access point. Moreover, among the six types of access traffic flows, the access traffic flow 1 (right-turning traffic from major street), flow 4 (left-turning traffic from access point), and flow 5 (left-turning traffic from major street) cause a more significant effect on lane group capacity than others. Some guidance on the mitigation of the negative effect is provided for practitioners. PMID:26726998

Acute tamponade alters subendo- and subepicardial pressure-flow relations differently during vasodilation.

PubMed

Kingma, J G; Martin, J; Rouleau, J R

1994-07-01

Instantaneous diastolic left coronary artery pressure-flow relations (PFR) shift during acute tamponade as pressure surrounding the heart increases. Coronary pressure at zero flow (Pf = 0) on the linear portion of the PFR is the weighted mean of the different myocardial waterfall pressures, the distribution of which varies across the left ventricular wall during diastole. However, instantaneous PFR measured in large epicardial coronary arteries cannot be used to estimate Pf = 0 in the different myocardial tissue layers. During coronary vasodilatation in a capacitance-free model, myocardial PFR differs from subendocardium to subepicardium. Therefore, we studied the effects of acute tamponade during maximal pharmacology induced coronary vasodilatation on myocardial PFR in in situ anesthetized dogs. Tamponade reduced cardiac output, aortic pressure, and coronary blood flow. Results demonstrate that different mechanisms influence distribution of myocardial blood flow during tamponade. Subepicardial vascular resistance is unchanged and the extrapolated Pf = 0 is increased, thereby shifting PFR to a higher intercept on the pressure axis. Subendocardial vascular resistance is increased while the extrapolated Pf = 0 remains unchanged. Results indicate that in the setting of acute tamponade with coronary vasodilatation different mechanisms regulate the distribution of myocardial blood flow: in the subepicardium only outflow pressure increases, whereas in the subendocardium only vascular resistance increases.

Long-term, repeated measurements of mouse cortical microflow at the same region of interest with high spatial resolution.

PubMed

Tomita, Yutaka; Pinard, Elisabeth; Tran-Dinh, Alexy; Schiszler, Istvan; Kubis, Nathalie; Tomita, Minoru; Suzuki, Norihiro; Seylaz, Jacques

2011-02-04

A method for long-term, repeated, semi-quantitative measurements of cerebral microflow at the same region of interest (ROI) with high spatial resolution was developed and applied to mice subjected to focal arterial occlusion. A closed cranial window was chronically implanted over the left parieto-occipital cortex. The anesthetized mouse was placed several times, e.g., weekly, under a dynamic confocal microscope, and Rhodamine B-isothiocyanate-dextran was each time intravenously injected as a bolus, while microflow images were video recorded. Left and right tail veins were sequentially catheterized in a mouse three times at maximum over a 1.5 months' observation period. Smearing of the input function resulting from the use of intravenous injection was shown to be sufficiently small. The distal middle cerebral artery (MCA) was thermocoagulated through the cranial window in six mice, and five sham-operated mice were studied in parallel. Dye injection and video recording were conducted four times in this series, i.e., before and at 10 min, 7 and 30 days after sham operation or MCA occlusion. Pixelar microflow values (1/MTT) in a matrix of approximately 50×50 pixels were displayed on a two-dimensional (2-D) map, and the frequency distribution of the flow values was also calculated. No significant changes in microflow values over time were detected in sham-operated mice, while the time course of flow changes in the ischemic penumbral area in operated mice was similar to those reported in the literature. This method provides a powerful tool to investigate long-term changes in mouse cortical microflow under physiological and pathological conditions. Copyright © 2010 Elsevier B.V. All rights reserved.

Resting-state regional cerebral blood flow during adolescence: associations with initiation of substance use and prediction of future use disorders.

PubMed

Ramage, Amy E; Lin, Ai-Ling; Olvera, Rene L; Fox, Peter T; Williamson, Douglas E

2015-04-01

Adolescence is a period of developmental flux when brain systems are vulnerable to influences of early substance use, which in turn relays increased risk for substance use disorders. Our study intent was to assess adolescent regional cerebral blood flow (rCBF) as it relates to current and future alcohol use. The aim was to identify brain-based predictors for initiation of alcohol use and onset of future substance use disorders. Quantitative rCBF was assessed in 100 adolescents (age 12-15). Prospective behavioral assessments were conducted annually over a three-year follow-up period to characterize onset of alcohol initiation, future drinking patterns and use disorders. Comparisons amongst use groups (i.e., current-, future-, and non-alcohol using adolescents) identified rCBF associated with initiation of alcohol use. Regression by future drinking patterns identified rCBF predictive of heavier drinking. Survival analysis determined whether or not baseline rCBF predicted later development of use disorders. Baseline rCBF was decreased to the parietal cortex and increased to mesolimbic regions in adolescents currently using alcohol as well as those who would use alcohol in the future. Higher baseline rCBF to the left fusiform gyrus and lower rCBF to the right inferior parietal cortex and left cerebellum was associated with future drinking patterns as well as predicted the onset of alcohol and substance use disorders in this cohort. Variations in resting rCBF to regions within reward and default mode or control networks appear to represent trait markers of alcohol use initiation and are predictive of future development of use disorders. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Using thermal stress to model aspects of disease states.

PubMed

Wilson, Thad E; Klabunde, Richard E; Monahan, Kevin D

2014-07-01

Exposure to acute heat or cold stress elicits numerous physiological responses aimed at maintaining body temperatures. Interestingly, many of the physiological responses, mediated by the cardiovascular and autonomic nervous systems, resemble aspects of, or responses to, certain disease states. The purpose of this Perspective is to highlight some of these areas in order to explore how they may help us better understand the pathophysiology underlying aspects of certain disease states. The benefits of using this human thermal stress approach are that (1) no adjustments for inherent comparative differences in animals are needed, (2) non-medicated healthy humans with no underlying co-morbidities can be studied in place of complex patients, and (3) more mechanistic perturbations can be safely employed without endangering potentially vulnerable populations. Cold stress can be used to induce stable elevations in blood pressure. Cold stress may also be used to model conditions where increases in myocardial oxygen demand are not met by anticipated increases in coronary blood flow, as occurs in older adults. Lower-body negative pressure has the capacity to model aspects of shock, and the further addition of heat stress improves and expands this model because passive-heat exposure lowers systemic vascular resistance at a time when central blood volume and left-ventricular filling pressure are reduced. Heat stress can model aspects of heat syncope and orthostatic intolerance as heat stress decreases cerebral blood flow and alters the Frank-Starling mechanism resulting in larger decreases in stroke volume for a given change in left-ventricular filling pressure. Combined, thermal perturbations may provide in vivo paradigms that can be employed to gain insights into pathophysiological aspects of certain disease states. Copyright © 2014 Elsevier Ltd. All rights reserved.

Relationship between the change of language symptoms and the change of regional cerebral blood flow in the recovery process of two children with acquired aphasia.

PubMed

Kozuka, Junko; Uno, Akira; Matsuda, Hiroshi; Toyoshima, Yoshiya; Hamano, Shin-Ichiro

2017-06-01

This study aimed to investigate the relationship between the change of language symptoms and the change of regional cerebral blood flow (rCBF) in the recovery process of two children with acquired aphasia caused by infarctions from Moyamoya disease with an onset age of 8years. We compared the results for the Standard Language Test of Aphasia (SLTA) with rCBF changes in 7 language regions in the left hemisphere and their homologous regions in the right hemisphere at 4 time points from 3weeks for up to 5years after the onset of aphasia, while controlling for the effect of age. In both cases, strong correlations were seen within a hemisphere between adjacent regions or regions that are connected by neuronal fibers, and between some language regions in the left hemisphere and their homologous regions in the right hemisphere. Conversely, there were differences between the two cases in the time course of rCBF changes during their recovery process. Consistent with previous studies, the current study suggested that both hemispheres were involved in the long-term recovery of language symptoms in children with acquired aphasia. We suggest that the differences between both cases during their recovery process might be influenced by the brain states before aphasia, by which hemisphere was affected, and by the timing of the surgical revascularization procedure. However, the changes were observed in the data obtained for rCBF with strong correlations with the changes in language performance, so it is possible that rCBF could be used as a biomarker for language symptom changes. Copyright © 2017 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.

Identification of capillary rarefaction using intracoronary wave intensity analysis with resultant prognostic implications for cardiac allograft patients.

PubMed

Broyd, Christopher J; Hernández-Pérez, Francisco; Segovia, Javier; Echavarría-Pinto, Mauro; Quirós-Carretero, Alicia; Salas, Clara; Gonzalo, Nieves; Jiménez-Quevedo, Pilar; Nombela-Franco, Luis; Salinas, Pablo; Núñez-Gil, Ivan; Del Trigo, Maria; Goicolea, Javier; Alonso-Pulpón, Luis; Fernández-Ortiz, Antonio; Parker, Kim; Hughes, Alun; Mayet, Jamil; Davies, Justin; Escaned, Javier

2018-05-21

Techniques for identifying specific microcirculatory structural changes are desirable. As such, capillary rarefaction constitutes one of the earliest changes of cardiac allograft vasculopathy (CAV) in cardiac allograft recipients, but its identification with coronary flow reserve (CFR) or intracoronary resistance measurements is hampered because of non-selective interrogation of the capillary bed. We therefore investigated the potential of wave intensity analysis (WIA) to assess capillary rarefaction and thereby predict CAV. Fifty-two allograft patients with unobstructed coronary arteries and normal left ventricular (LV) function were assessed. Adequate aortic pressure and left anterior descending artery flow measurements at rest and with intracoronary adenosine were obtained in 46 of which 2 were lost to follow-up. In a subgroup of 15 patients, simultaneous RV biopsies were obtained and analysed for capillary density. Patients were followed up with 1-3 yearly screening angiography. A significant relationship with capillary density was noted with CFR (r = 0.52, P = 0.048) and the backward decompression wave (BDW) (r = -0.65, P < 0.01). Over a mean follow-up of 9.3 ± 5.2 years patients with a smaller BDW had an increased risk of developing angiographic CAV (hazard ratio 2.89, 95% CI 1.12-7.39; P = 0.03). Additionally, the index BDW was lower in those who went on to have a clinical CAV-events (P = 0.04) as well as more severe disease (P = 0.01). Within cardiac transplant patients, WIA is able to quantify the earliest histological changes of CAV and can predict clinical and angiographic outcomes. This proof-of-concept for WIA also lends weight to its use in the assessment of other disease processes in which capillary rarefaction is involved.

[Cockett's syndrome, May-Thurner syndrome, or iliac vein compression syndrome].

PubMed

Gil Martín, A R; Carreras Aja, M; Arrieta Ardieta, I; Labayen Azparren, I

2014-01-01

Iliac vein compression syndrome (also known as May-Thurner syndrome or Cockett's syndrome) is a rare clinical entity in which the left common iliac vein is compressed when it passes between the right common iliac artery and the spine. The sustained compression and trauma caused by the pulsatile force of the artery on the vein damage the intima and lead to the formation of membranes or bands in the vascular lumen that hinder or obstruct the flow of blood in the vein, favoring thrombus formation. The current treatment strategy of choice is endovascular vein patch angioplasty and stenting with the aim of improving the caliber of the lumen and enabling normal venous drainage. We present two cases of May-Thurner syndrome and review the clinical and CT findings. Copyright © 2011 SERAM. Published by Elsevier Espana. All rights reserved.

Aortic flow conditions predict ejection efficiency in the NHLBI-Sponsored Women's Ischemia Syndrome Evaluation (WISE).

PubMed

Doyle, Mark; Pohost, Gerald M; Bairey Merz, C Noel; Farah, Victor; Shaw, Leslee J; Sopko, George; Rogers, William J; Sharaf, Barry L; Pepine, Carl J; Thompson, Diane V; Rayarao, Geetha; Tauxe, Lindsey; Kelsey, Sheryl F; Biederman, Robert W W

2017-06-01

The Windkessel model of the cardiovascular system, both in its original wind-chamber and flow-pipe form, and in its electrical circuit analog has been used for over a century to modeled left ventricular ejection conditions. Using parameters obtained from aortic flow we formed a Flow Index that is proportional to the impedance of such a "circuit". We show that the impedance varies with ejection fraction (EF) in a manner characteristic of a resonant circuit with multiple resonance points, with each resonance point centrally located in a small range of EF values, i.e., corresponding to multiple contiguous EF bands. Two target populations were used: (I) a development group comprising male and female subjects (n=112) undergoing cardiovascular magnetic resonance (CMR) imaging for a variety of cardiac conditions. The Flow Index was developed using aortic flow data and its relationship to left ventricular EF was shown. (II) An illustration group comprised of female subjects from the Women's Ischemia Syndrome Evaluation (WISE) (n=201) followed for 5 years for occurrence of major adverse cardiovascular events (MACE). Flow data was not available in this group but since the Flow Index was related to the EF we noted the MACE rate with respect to EF. The EFs of the development population covered a wide range (9%-76%) traversing six Flow Index resonance bands. Within each Flow Index resonance band the impedance varied from highly capacitive at the lower range of EF through minimal impedance at resonance, to highly inductive at the higher range of EF, which is characteristic of a resonant circuit. When transitioning from one EF band to a higher band, the Flow Index made a sudden transition from highly inductive to capacitive impedance modes. MACE occurred in 26 (13%) of the WISE (illustration) population. Distance in EF units (Delta center ) from the central location between peaks of MACE activity was derived from EF data and was predictive of MACE rate with an area under the receiver operator curve of 0.73. Of special interest, Delta center was highly predictive of MACE in the sub-set of women with EF >60% (AUC 0.79) while EF was no more predictive than random chance (AUC 0.48). A Flow Index that describes impedance conditions of left ventricular ejection can be calculated using data obtained completely from the ascending aorta. The Flow Index exhibits a periodic variation with EF, and in a separate illustration population the occurrence of MACE was observed to exhibit a similar periodic variation with EF, even in cases of normal EF.

Interrelationship of mid-diastolic mitral valve motion, pulmonary venous flow, and transmitral flow.

PubMed

Keren, G; Meisner, J S; Sherez, J; Yellin, E L; Laniado, S

1986-07-01

This study offers a unifying mechanism of left ventricular filling dynamics to link the unexplained mid-diastolic motion of the mitral valve with an associated increase in transmitral flow, with the phasic character of pulmonary vein flow, and with changes in the atrioventricular pressure difference. M mode echograms of mitral valve motion and Doppler echocardiograms of mitral and pulmonary vein flow velocities were recorded in 12 healthy volunteers (heart rate = 60 +/- 9 beats/min). All echocardiograms showed an undulation in the mitral valve (L motion) at a relatively constant delay from the peak of the diastolic phase of pulmonary vein flow (K phase). In six subjects, the L motion was also associated with a distinct wave of mitral flow (L wave). Measured from the onset of the QRS complex, Q-K was 577 +/- 39 msec; Q-L was 703 +/- 42 msec, and K-L was 125 +/- 16 msec. Multiple measurements within each subject during respiratory variations in RR interval indicated exceptionally small differences in the temporal relationships (mean coefficient of variation 2%). Early rapid flow deceleration is caused by a reversal of the atrioventricular pressure gradient, and the L wave arises from the subsequent reestablishment of a positive gradient due to left atrial filling via the pulmonary veins. The mitral valve moves passively in response to the flowing blood and the associated pressure difference. This interpretation is confirmed by (1) a computational model, and (2) a retrospective analysis of data from patients with mitral stenosis and from conscious dogs instrumented to measure transmitral pressure-flow relationships.

Relationship between interatrial communication, ductus arteriosus, and pulmonary flow patterns in fetuses with transposition of the great arteries: prediction of neonatal desaturation.

PubMed

Vaujois, Laurence; Boucoiran, Isabelle; Preuss, Christophe; Brassard, Myriam; Houde, Christine; Fouron, Jean C; Raboisson, Marie-Josée

2017-09-01

The relationship between interatrial communication, ductus arteriosus, and pulmonary flow in transposition of the great arteries and intact ventricular septum may help predict postnatal desaturation. Echocardiographic data of 45 fetuses with transposition of the great arteries and intact ventricular septum and 50 age-matched controls were retrospectively reviewed. Interatrial communication, left and right ventricular output, flow in the ductus arteriosus, as well as effective pulmonary flow were measured. Patients were divided into two groups on the basis of postnatal saturations: group 1 had saturations ⩽50% and group 2 >50%. Of 45 fetuses, 13 (26.7%) were classified into group 1. Compared with fetuses in group 2, they had a smaller interatrial communication (2.9 versus 4.0 mm, p=0.004) and more retrograde diastolic flow in the ductus arteriosus (92 versus 23%, p=0.002). Both groups showed a significant decrease in ductal flow compared with controls. Patients in group 2 had a higher effective pulmonary flow compared with controls. There was a mild correlation between left ventricular output and size of the interatrial communication (Spearman's rank correlation 0.44). A retrograde diastolic flow is present in most of the fetuses with postnatal desaturation. Fetuses with transposition of the great arteries have a lower flow through the ductus arteriosus compared with controls. Fetuses without restrictive foramen ovale have higher effective pulmonary flow. Peripheral pulmonary vasodilatation due to higher oxygen saturation in pulmonary arteries in the case of transposition of the great arteries could be one possible cause.

Aortic Wave Dynamics and Its Influence on Left Ventricular Workload

PubMed Central

Pahlevan, Niema M.; Gharib, Morteza

2011-01-01

The pumping mechanism of the heart is pulsatile, so the heart generates pulsatile flow that enters into the compliant aorta in the form of pressure and flow waves. We hypothesized that there exists a specific heart rate at which the external left ventricular (LV) power is minimized. To test this hypothesis, we used a computational model to explore the effects of heart rate (HR) and aortic rigidity on left ventricular (LV) power requirement. While both mean and pulsatile parts of the pressure play an important role in LV power requirement elevation, at higher rigidities the effect of pulsatility becomes more dominant. For any given aortic rigidity, there exists an optimum HR that minimizes the LV power requirement at a given cardiac output. The optimum HR shifts to higher values as the aorta becomes more rigid. To conclude, there is an optimum condition for aortic waves that minimizes the LV pulsatile load and consequently the total LV workload. PMID:21853075

Echocardiographic predictors of coil vs device closure in patients undergoing percutaneous patent ductus arteriosus closure.

PubMed

Roushdy, Alaa; Abd El Razek, Yasmeen; Mamdouh Tawfik, Ahmed

2018-01-01

To determine anatomic and hemodynamic echocardiographic predictors for patent ductus arteriosus (PDA) device vs coil closure. Seventy-six patients who were referred for elective transcatheter PDA closure were enrolled in the study. All patients underwent full echocardiogram including measurement of the PDA pulmonary end diameter, color flow width and extent, peak and end-diastolic Doppler gradients across the duct, diastolic flow reversal, left atrial dimensions and volume, left ventricular sphericity index, and volumes. The study group was subdivided into 2 subgroups based on the mode of PDA closure whether by coil (n = 42) or device (n = 34). Using univariate analysis there was a highly significant difference between the 2 groups as regard the pulmonary end diameter measured in both the suprasternal and parasternal short-axis views as well as the color flow width and color flow extent (P < .0001). The device closure group had statistically significant higher end-systolic and end-diastolic volumes indexed, left atrial volume, and diastolic flow reversal. Receiver operating characteristic curve analysis showed a pulmonary end diameter cutoff point from the suprasternal view > 2.5 mm and from parasternal short-axis view > 2.61 mm to have the highest balanced sensitivity and specificity to predict the likelihood for device closure (AUC 0.971 and 0.979 respectively). The pulmonary end diameter measured from the suprasternal view was the most independent predictor of device closure. The selection between PDA coil or device closure can be done on the basis of multiple anatomic and hemodynamic echocardiographic variables. © 2017 Wiley Periodicals, Inc.

Quantification of left and right atrial kinetic energy using four-dimensional intracardiac magnetic resonance imaging flow measurements.

PubMed

Arvidsson, Per M; Töger, Johannes; Heiberg, Einar; Carlsson, Marcus; Arheden, Håkan

2013-05-15

Kinetic energy (KE) of atrial blood has been postulated as a possible contributor to ventricular filling. Therefore, we aimed to quantify the left (LA) and right (RA) atrial blood KE using cardiac magnetic resonance (CMR). Fifteen healthy volunteers underwent CMR at 3 T, including a four-dimensional phase-contrast flow sequence. Mean LA KE was lower than RA KE (1.1 ± 0.1 vs. 1.7 ± 0.1 mJ, P < 0.01). Three KE peaks were seen in both atria: one in ventricular systole, one during early ventricular diastole, and one during atrial contraction. The systolic LA peak was significantly smaller than the RA peak (P < 0.001), and the early diastolic LA peak was larger than the RA peak (P < 0.05). Rotational flow contained 46 ± 7% of total KE and conserved energy better than nonrotational flow did. The KE increase in early diastole was higher in the LA (P < 0.001). Systolic KE correlated with the combination of atrial volume and systolic velocity of the atrioventricular plane displacement (r(2) = 0.57 for LA and r(2) = 0.64 for RA). Early diastolic KE of the LA correlated with left ventricle (LV) mass (r(2) = 0.28), however, no such correlation was found in the right heart. This suggests that LA KE increases during early ventricular diastole due to LV elastic recoil, indicating that LV filling is dependent on diastolic suction. Right ventricle (RV) relaxation does not seem to contribute to atrial KE. Instead, RA KE generated during ventricular systole may be conserved in a hydraulic "flywheel" and transferred to the RV through helical flow, which may contribute to RV filling.

Enhanced ventricular pump function and decreased reservoir backflow sustain rise in pulmonary blood flow after reduction of lung liquid volume in fetal lambs.

PubMed

Smolich, Joseph J

2014-02-15

Although a reduction in lung liquid volume increases fetal pulmonary blood flow, the changes in central flow patterns that sustain this increased pulmonary perfusion are unknown. To address this issue, eight anesthetized late-gestation fetal sheep were instrumented with pulmonary trunk (PT), ductus arteriosus (DA), and left pulmonary artery (PA) micromanometer catheters and transit-time flow probes, with blood flow profile and wave intensity analyses performed at baseline and after withdrawal of lung liquid via an endotracheal tube. Reducing lung liquid volume by 19 ± 6 ml/kg (mean ± SD) augmented right ventricular power by 34% (P < 0.001), with distribution of an accompanying increase in mean PT blood flow (245 ± 63 ml/min, P < 0.001) to the lungs (169 ± 91 ml/min, P = 0.001) and across the DA (77 ± 92 ml/min, P = 0.04). However, although PT and DA flow increments were confined to systole and were related to an increased magnitude of flow-increasing, forward-running compression waves, the rise in PA flow spanned both systole (108 ± 66 ml/min) and diastole (61 ± 32 ml/min). Flow profile analysis showed that the step-up in PA diastolic flow was associated with diminished PA diastolic backflow and accompanied by a lesser degree of diastolic right-to-left DA shunting. These data suggest that an increased pulmonary blood flow after reduction of lung liquid volume is associated with substantial changes in PT-DA-PA interactions and underpinned by two main factors: 1) enhanced right ventricular pump function that increases PA systolic inflow and 2) decreased PA diastolic backflow that arises from a fundamental change in PA reservoir function, thereby resulting in greater passage of systolic inflow through the lungs.

Impaired global myocardial flow dynamics despite normal left ventricular function and regional perfusion in chronic kidney disease: a quantitative analysis of clinical 82Rb PET/CT studies.

PubMed

Fukushima, Kenji; Javadi, Mehrbod S; Higuchi, Takahiro; Bravo, Paco E; Chien, David; Lautamäki, Riikka; Merrill, Jennifer; Nekolla, Stephan G; Bengel, Frank M

2012-06-01

Impaired global myocardial flow reserve (MFR) may be associated with increased risk for cardiac events and coronary artery disease progression. Chronic kidney disease (CKD) is also considered a risk factor for cardiovascular disease. We sought to investigate the effect of CKD on the myocardial microcirculation in patients referred for clinical (82)Rb PET/CT, who had normal left ventricular (LV) function and no flow-limiting coronary artery disease. Estimated glomerular filtration rate (eGFR) was available for 230 patients who had undergone rest and pharmacologic stress (82)Rb PET/CT for suspected coronary artery disease. CKD was defined as an eGFR less than 60 mL/min/1.73 m(2). After patients with hemodialysis, a renal transplant, abnormal regional perfusion (summed stress score > 4), or reduced LV function (LV ejection fraction < 45%) were excluded, 40 CKD patients remained. Those were compared with a control group without CKD, which was matched for age, sex, coronary risk factors, and systemic hemodynamics (n = 42). List-mode acquisition of PET enabled quantification of myocardial blood flow (MBF) and MFR using a previously validated retention model with correction for (82)Rb extraction. Rest MBF was normalized to rate-pressure product. Mean eGFR in the CKD group was reduced (44 ± 14 vs. 99 ± 28 mL/min/1.73 m(2); P < 0.0001), and creatinine was significantly elevated, compared with controls (1.9 ± 1.1 vs. 0.8 ± 0.2 mg/dL; P < 0.0001). MFR was significantly reduced in CKD (2.2 ± 1.0 vs. 3.0 ± 1.2 for controls; P = 0.027). This reduction was mainly due to increased rest MBF (1.1 ± 0.4 in CKD vs. 0.8 ± 0.2 mL/min/g in controls; P = 0.007). Stress myocardial flow was comparable between both groups (2.3 ± 0.9 vs. 2.3 ± 0.8 mL/min/g; P = 0.08). Overall, MFR was significantly correlated with eGFR (r = 0.41; P = 0.0005). Stress MBF did not correlate with eGFR (r = 0.002; P = 0.45), but rest MBF showed an inverse correlation (r = -0.49; P < 0.0001). Rest MBF was also inversely correlated with hemoglobin (r = -0.28; P = 0.014), but only eGFR was an independent correlate at multivariate analysis. MFR is impaired in patients with renal insufficiency with normal regional perfusion and LV function, mostly because of elevated rest flow. Absolute quantification of flow may be useful to identify microvascular dysfunction as a precursor of clinically overt coronary disease in this specific risk group.

Mechanical support of total cavopulmonary connection with an axial flow pump.

PubMed

Riemer, R Kirk; Amir, Gabriel; Reichenbach, Steven H; Reinhartz, Olaf

2005-08-01

Even under optimal circumstances, total cavopulmonary connection is associated with a continuous late risk of death. Hemodynamics are distinctly abnormal, with increased systemic venous pressures and frequent low cardiac output. Our study uses a sheep model of total cavopulmonary connection to test the response to axial flow pump (Thoratec HeartMate II; Thoratec Corporation (Pleasanton, Calif)) support of total cavopulmonary connection, which might be suitable to treat patients with failing Fontan circulation. Eight sheep (42-48 kg) were studied. After pilot studies in 3 animals, 5 underwent both pump-supported and nonsupported total cavopulmonary connection in alternating sequence for up to 2 hours. This was achieved with a 12-mm polytetrafluoroethylene graft from the (distally ligated) superior vena cava to the main pulmonary artery and a cannula placed in the inferior vena cava with an attached 16-mm Dacron graft to the main pulmonary artery. Pressures (arterial, inferior vena cava, left atrium, and pulmonary artery) and flows (ascending aorta and inferior vena cava) were recorded over 1 hour both with unsupported total cavopulmonary connection and after placing an axial flow pump (Thoratec HeartMate II) between the inferior vena caval inflow cannula and the main pulmonary artery. Under nonsupported total cavopulmonary connection circulation, inferior vena caval and aortic blood flow decreased by nearly 50%. Inferior vena caval pressure nearly doubled, whereas arterial pressure decreased by one third. Pulmonary artery pressure became nonpulsatile; however, mean pulmonary artery pressure and left atrial pressure did not change significantly. With pump-supported Fontan circulation, cardiac output, inferior vena caval flow, and arterial pressure returned to baseline. Inferior vena caval pressure decreased to below baseline levels. Mean pulmonary artery pressure and left atrial pressure again remained unchanged. Axial flow pump support from the inferior vena cava to the pulmonary artery can prevent the substantial decrease of aortic flow and pressure associated with total cavopulmonary connection and can reverse its poor hemodynamics. This is a simple model that can be used to further evaluate the potential of mechanical support as a treatment option in failing Fontan circulation.

Regional cerebral blood flow changes associated with clitorally induced orgasm in healthy women.

PubMed

Georgiadis, Janniko R; Kortekaas, Rudie; Kuipers, Rutger; Nieuwenburg, Arie; Pruim, Jan; Reinders, A A T Simone; Holstege, Gert

2006-12-01

There is a severe lack of knowledge regarding the brain regions involved in human sexual performance in general, and female orgasm in particular. We used [15O]-H2O positron emission tomography to measure regional cerebral blood flow (rCBF) in 12 healthy women during a nonsexual resting state, clitorally induced orgasm, sexual clitoral stimulation (sexual arousal control) and imitation of orgasm (motor output control). Extracerebral markers of sexual performance and orgasm were rectal pressure variability (RPstd) and perceived level of sexual arousal (PSA). Sexual stimulation of the clitoris (compared to rest) significantly increased rCBF in the left secondary and right dorsal primary somatosensory cortex, providing the first account of neocortical processing of sexual clitoral information. In contrast, orgasm was mainly associated with profound rCBF decreases in the neocortex when compared with the control conditions (clitoral stimulation and imitation of orgasm), particularly in the left lateral orbitofrontal cortex, inferior temporal gyrus and anterior temporal pole. Significant positive correlations were found between RPstd and rCBF in the left deep cerebellar nuclei, and between PSA and rCBF in the ventral midbrain and right caudate nucleus. We propose that decreased blood flow in the left lateral orbitofrontal cortex signifies behavioural disinhibition during orgasm in women, and that deactivation of the temporal lobe is directly related to high sexual arousal. In addition, the deep cerebellar nuclei may be involved in orgasm-specific muscle contractions while the involvement of the ventral midbrain and right caudate nucleus suggests a role for dopamine in female sexual arousal and orgasm.

Left atrial booster function in valvular heart disease.

PubMed

Heidenreich, F P; Shaver, J A; Thompson, M E; Leonard, J J

1970-09-01

This study was designed to assess atrial booster pump action in valvular heart disease and to dissect booster pump from reservoir-conduit functions. In five patients with aortic stenosis and six with mitral stenosis, sequential atrioventricular (A-V) pacing was instituted during the course of diagnostic cardiac catheterization. Continuous recording of valvular gradient allowed estimation of flow for each cardiac cycle by transposition of the Gorlin formula. Left ventricular ejection time and left ventricular stroke work in aortic stenosis or left ventricular mean systolic pressure in mitral stenosis were also determined. Control observations were recorded during sequential A-V pacing with well-timed atrial systole. Cardiac cycles were then produced with no atrial contraction but undisturbed atrial reservoir function by intermittently interrupting the atrial pacing stimulus during sequential A-V pacing. This intervention significantly reduced valvular gradient, flow, left ventricular ejection time, and left ventricular mean systolic pressure or stroke work. Cardiac cycles were then produced with atrial booster action eliminated by instituting synchronous A-V pacing. The resultant simultaneous contraction of the atrium and ventricle not only eliminated effective atrial systole but also placed atrial systole during the normal period of atrial reservoir function. This also significantly reduced all the hemodynamic measurements. However, comparison of the magnitude of change from these two different pacing interventions showed no greater impairment of hemodynamic state when both booster pump action and reservoir function were impaired than when booster pump action alone was impaired. The study confirms the potential benefit of well placed atrial booster pump action in valvular heart disease in man.

Suction prevention and physiologic control of continuous flow left ventricular assist devices using intrinsic pump parameters.

PubMed

Wang, Yu; Koenig, Steven C; Slaughter, Mark S; Giridharan, Guruprasad A

2015-01-01

The risk for left ventricular (LV) suction during left ventricular assist devices (LVAD) support has been a clinical concern. Current development efforts suggest LVAD suction prevention and physiologic control algorithms may require chronic implantation of pressure or flow sensors, which can be unreliable because of baseline drift and short lifespan. To overcome this limitation, we designed a sensorless suction prevention and physiologic control (eSPPC) algorithm that only requires LVAD intrinsic parameters (pump speed and power). Two gain-scheduled, proportional-integral controllers maintain a differential pump speed (ΔRPM) above a user-defined threshold to prevent LV suction while maintaining an average reference differential pressure (ΔP) between the LV and aorta. ΔRPM is calculated from noisy pump speed measurements that are low-pass filtered, and ΔP is estimated using an extended Kalman filter. Efficacy and robustness of the eSPPC algorithm were evaluated in silico during simulated rest and exercise test conditions for 1) excessive ΔP setpoint (ES); 2) rapid eightfold increase in pulmonary vascular resistance (PVR); and 3) ES and PVR. Simulated hemodynamic waveforms (LV pressure and volume; aortic pressure and flow) using only intrinsic pump parameters showed the feasibility of our proposed eSPPC algorithm in preventing LV suction for all test conditions.

Flow characteristics of the Clearwater River and tributaries from Clearbrook to Plummer, northwestern Minnesota

USGS Publications Warehouse

Payne, G.A.

1989-01-01

During March through October 1986, 52,560 acre-feet of water passed the continuous-record stream gaging station on the Clearwater River near Clearbrook, Minnesota, 4.8 river miles upstream from the Red Lake Indian Reservation. Flow at the downstream boundary of the Reservation totaled 93,770 acre-feet. The increase in Clearwater River flow in the reach bordering the Reservation equaled 32,950 acre-feet; 60 percent of the increase occurred during March, April, and May. During those months, flow in the Clearwater River was augmented by flow from Kiwosay Reservoir and Butcher Knife Creek, which are located on the Reservation. Daily streamflow records showed that flow in the river increased in the Reservation reach throughout the study except for 13 days during October when losses occurred. At the downstream Reservation boundary, all daily mean flows exceeded the 36 cubic feet per second minimum flow required by the Minnesota Department of Natural Resources for the gaging station at Plummer, Minnesota located 29.9 miles downstream from the Reservation boundary. Monthly flows generally followed expected seasonal trends, with the highest monthly totals occurring in April and May and the lowest monthly totals occurring during August, September, and October. Seasonal trends were modified by reservoir releases, withdrawals for irrigation, and return flows that resulted from drainage of adjacent wild-rice fields. A series of flow measurements showed that localized withdrawals and return flows at times exceeded 20 percent of total streamflow. Discharge measurements made during low flow indicated higher rates of groundwater discharge in the vicinity of the Kiwosay Reservoir than in other parts of the study reach. Measurements made during August indicated that groundwater discharge in the reach of the river bordering the Reservation resulted in a flow gain of about 20 percent. Analysis of long-term streamflow records showed that near-average hydrologic conditions prevailed during the study period.

Myocardial metabolism during exposure to carbon monoxide in the conscious dog.

NASA Technical Reports Server (NTRS)

Adams, J. D.; Erickson, H. H.; Stone, H. L.

1973-01-01

Investigation of the relationship between coronary flow, heart rate, left ventricular function, and myocardial oxygen consumption at increasing levels of carboxyhemoglobin in conscious dogs. The results demonstrate a linear increase in coronary flow and heart rate as the carboxyhemoglobin increases up to 20%. Myocardial oxygen consumption declined during the same period.

Non invasive Measurements of Myocardial Hypertrophy in Patients with Essential Hypertension Treated with Eprosartan: Contribution of the Physics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cabrera Sole, Ricardo

Objective: The main objective of this study was to evaluate the effects of the treatment with eprosartan on cardiac hypertrophy in hypertensive patients using the echocardiogram to measure the hypertrophy of left ventricle. We studied 60 untreated patients diagnosed of mild to moderate hypertension which received after the diagnosis 600 mg/day of eprosartan, a novel direct angiotensin inhibitor recently introduced to treat hypertension. All patients were submitted to a standard echocardiographic study before the treatment and after 6 months of it We evaluated by echocardiogram the following parameters: left ventricular septum and posterior wall thickness, left ventricular mass, E/A indexmore » of mitral flow considering abnormal when this index was less than 1, and left ventricular ejection fraction. Results: at the beginning we found a systolic/diastolic pressures of 165{+-}9/ 96{+-}4 mmHg compared with the end of study of 124{+-}2/79{+-}3 mmHg (p<0.05). Septum and posterior wall thickness were respectively at baseline 13.2{+-}2 and 12.1{+-}1.1 mmHg and at the end 11.5{+-}1.2 and 10.5{+-}1.3 mmHg (p<0.05 for both of them). The E/A mitral flow index was less than 1 at baseline in 45 patients compared with 19 patients after treatment (p<0.05). Respect to left ventricular mass we found at the beginning 232{+-}7.5 gr., compared to 194{+-}9 gr., at the end of this study (p<0.05). We did not find any significant differences regarding left ventricular ejection fraction between both groups. Conclusions: we can remark that eprosartan is a very useful drug to reduce not only blood pressure but also left ventricular hypertrophy and improve left ventricular diastolic function in patients with essential hypertension according with parameters measured with non invasive methods.« less

116. PNEUMATIC SUPPLY PANEL IN CENTER OF VEHICLE MECHANICAL SYSTEMS ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

116. PNEUMATIC SUPPLY PANEL IN CENTER OF VEHICLE MECHANICAL SYSTEMS ROOM (111) OF LSB (BLDG. 770), FACING NORTH. CONTROLS FOR FLOW AND PRESSURE REGULATION OF NITROGEN ON RIGHT SIDE OF PANEL; CONTROLS FOR HELIUM ON LEFT SIDE OF PANEL (AT LEFT EDGE OF PHOTO). - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 West, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

Design and numeric evaluation of a novel axial-flow left ventricular assist device.

PubMed

Toptop, Koral; Kadipasaoglu, Kamuran A

2013-01-01

Virtual design characteristics and performance of the first Turkish axial-flow left ventricular assist device (LVAD) are presented, with emphasis on rotor geometry. The patented rotor design includes a central flow channel carved inside the main block, which carries permanent magnets. A concentric rotor-stator gap minimizes the distance between respective magnets, improving electromagnetic efficiency and creating a second blood pathway. Dual sets of three helical blades, placed on the shaft and external surface of the rotor block, ensure unidirectionality. Hemodynamic performance was tested with computational fluid dynamics (CFD); and rotor-blade geometry was optimized, to maximize overall efficiency d and minimize backflow and wall shear stresses. For a shaft radius of 4.5 mm, rotor blade height of 2.5 mm, and blade inlet and exit metal angles of 67° and 32°, pump operation at the nominal head-flow combination (5 L/min and 100.4 mm Hg) was achieved at a rotor speed of 10,313 rpm. At the nominal point, backflow as percent of total flow was 7.29 and 29.87% at rotor inlet and exit, respectively; overall hydraulic efficiency reached 21.59%; and maximum area-averaged shroud shear was 520 Pa. Overall efficiency peaked at 24.07% for a pump flow of 6.90 L/min, and averaged at 22.57% within the flow range of 4-8 L/min. We concluded that the design satisfies initial rotor design criteria, and that continued studies with diffuser optimization and transient flow analysis are warranted.

SLC7 family transporters control the establishment of left-right asymmetry during organogenesis in medaka by activating mTOR signaling.

PubMed

Asaoka, Yoichi; Nagai, Yoko; Namae, Misako; Furutani-Seiki, Makoto; Nishina, Hiroshi

2016-05-20

The precise government of the left-right (LR) specification of an organ is an essential aspect of its morphogenesis. Multiple signaling cascades have been implicated in the establishment of vertebrate LR asymmetry. Recently, mTOR signaling was found to critically regulate the development of LR asymmetry in zebrafish. However, the upstream factor(s) that activate mTOR signaling in the context of LR specification are as yet unknown. In this study, we identify the SLC7 amino acid transporters Slc7a7 and Slc7a8 as novel regulators of LR asymmetry development in the small fish medaka. Knockdown of Slc7a7 and/or Slc7a8 in medaka embryos disrupted LR organ asymmetries. Depletion of Slc7a7 hindered left-sided expression of the southpaw (spaw) gene, which is responsible for LR axis determination. Work at the cellular level revealed that Slc7a7 coordinates ciliogenesis in the epithelium of Kupffer's vesicle and thereby the generation of the nodal fluid flow required for LR asymmetry. Interestingly, knockdown of Slc7a7 depressed mTOR signaling activity in medaka embryos. Treatment with rapamycin, an inhibitor of mTOR signaling, together with Slc7a7 knockdown synergistically perturbed spaw expression, indicating an interaction between Slc7a7 and mTOR signaling affecting gene expression required for LR specification. Taken together, our results demonstrate that Slc7a7 governs the regulation of LR asymmetry development via the activation of mTOR signaling. Copyright © 2016 Elsevier Inc. All rights reserved.

Chronic intermittent hypobaric hypoxia attenuates radiation induced heart damage in rats.

PubMed

Wang, Jun; Wu, Yajing; Yuan, Fang; Liu, Yixian; Wang, Xuefeng; Cao, Feng; Zhang, Yi; Wang, Sheng

2016-09-01

Radiation-induced heart damage (RIHD) is becoming an increasing concern for patients and clinicians due to the use of radiotherapy for thoracic tumor. Chronic intermittent hypobaric hypoxia (CIHH) preconditioning has been documented to exert a cardioprotective effect. Here we hypothesized that CIHH was capable of attenuating functional and structural damage in a rat model of RIHD. Male adult Sprague-Dawley rats were randomly divided into 4 groups: control, radiation, CIHH and CIHH plus radiation. Cardiac function was measured using Langendorff perfusion in in vitro rat hearts. Cardiac fibrosis, oxidative stress and endoplasmic reticulum stress (ERS) was assessed by quantitative analysis of protein expression. No significant difference between any two groups was observed in baseline cardiac function as assessed by left ventricular end diastolic pressure (LVEDP), left ventricular developing pressure (LVDP) and the derivative of left ventricular pressure (±LVdp/dt). When challenged by ischemia/reperfusion, LVEDP was increased but LVDP and ±LVdp/dt was decreased significantly in radiation group compared with controls, accompanied by an enlarged infarct size and decreased coronary flow. Importantly, CIHH dramatically improved radiation-induced damage of cardiac function and blunted radiation-induced cardiac fibrosis in the perivascular and interstitial area. Furthermore, CIHH abrogated radiation-induced increase in malondialdehyde and enhanced total superoxide dismutase activity, as well as downregulated expression levels of ERS markers like GRP78 and CHOP. CIHH pretreatment alleviated radiation-induced damage of cardiac function and fibrosis. Such a protective effect was closely associated with suppression of oxidative stress and ERS responses. Copyright © 2016 Elsevier Inc. All rights reserved.

Rare case of diffuse spinal arachnoiditis following a complicated vertebral artery dissection.

PubMed

Atallah, Elias; Dang, Sophia; Rahm, Sage; Feghali, James; Nohra, Chalouhi; Tjoumakaris, Stavropoula; Rosenwasser, Robert H; Zarzour, Hekmat; Herial, Nabeel; Gooch, Michael Reid; Jabbour, Pascal

2018-06-01

Spinal arachnoiditis (SA) is an extremely rare and delayed complication of subarachnoid hemorrhage (SAH). Little is known about its underlying pathogenesis and subsequent clinical course. A middle-aged patient presented with the worst headache of her life and a grade 3 SAH of the basal-cisterns and posterior fossa was identified on Computed Tomography scans (CT). Angiography revealed a ruptured dissecting aneurysm of the left vertebral artery (VA-V4), as well as an unruptured left Anterior Cerebral Artery (ACA-A1) aneurysm. The VA aneurysm was treated with flow diversion. The patient re-ruptured the stented aneurysm, another telescoping pipeline was placed. The patient developed polymicrobial ventriculitis, and returned several months later complaining of paraparesis and left sided weakness. Magnetic Resonance Imaging (MRI) revealed diffuse thecal dural thickening from the cervicomedullary junction to the sacrum. Loculations, diffuse edema and cord compression were noticed along the inferior surface of the cerebellum, and the cervico-thoracic spine with a T4-T6 syrinx. The patient underwent a posterior (T4-T8) spinal fusion and (T5-T7) decompression with arachnoid-cyst fenestration and placement of a subarachnoid-pleural shunt. On latest follow-up, the patient is weaning off the thoraco-lumbosacral orthosis and ambulating with a cane. SA is often a complicated two-staged disease in which a "free interval phase" separates the initial inflammatory reaction (IIR) from the late adhesive phase. Posterior fossa bleeding, warranting prolonged surveillance, additional bleeding and ventriculitis might augment the risk and the severity of arachnoiditis. Copyright © 2018 Elsevier Ltd. All rights reserved.

Effect of Neurohormonal Blockade Drug Therapy on Outcomes and Left Ventricular Function and Structure After Left Ventricular Assist Device Implantation.

PubMed

Grupper, Avishay; Zhao, Yanjun M; Sajgalik, Pavol; Joyce, Lyle D; Park, Soon J; Pereira, Naveen L; Stulak, John M; Burnett, John C; Edwards, Brooks S; Daly, Richard C; Kushwaha, Sudhir S; Schirger, John A

2016-06-01

Neurohormonal blockade drug therapy (NHBDT) is the cornerstone therapy in heart failure (HF) management for promoting reverse cardiac remodeling and improving outcomes. It's utility in left ventricular assist device (LVAD) supported patients remains undefined. Sixty-four patients who received continuous flow LVAD at our institution were retrospectively reviewed and divided into 2 groups: no-NHBDT group (n = 33) received LVAD support only and NHBDT group (n = 31) received concurrent NHBDT based on the clinical judgment of the attending physicians. Cardiac remodeling (echocardiographic parameters and biomarkers) and clinical outcome (functional status, HF-related hospital readmissions, and mortality) data were collected. A statistically significant increase in ejection fraction, decrease in LV end-diastolic diameter index and LV mass index, and a sustained reduction in N-terminal pro B-type natriuretic peptide (NTproBNP) were observed in the NHBDT group at 6 months after LVAD implant (p <0.05). NHBDT-treated patients experienced significantly greater improvement in New York Heart Association functional classification and 6-minute-walk distance throughout the study. The combined end point of cardiovascular death or HF hospitalization was significantly reduced in patients receiving NHBDT (p = 0.013) associated primarily with a 12.1% absolute reduction in HF-related hospitalizations (p = 0.046). In conclusion, NHBDT in LVAD-supported patients is associated with a significant reversal in adverse cardiac remodeling and a reduction in morbidity and mortality compared with LVAD support alone. Copyright © 2016 Elsevier Inc. All rights reserved.

Procollagen type III amino terminal peptide and myocardial fibrosis: A study in hypertensive patients with and without left ventricular hypertrophy.

PubMed

dos Santos Moreira, Carlos; Serejo, Fátima; Alcântara, Paula; Ramalhinho, Vítor; Braz Nogueira, J

2015-05-01

An exaggerated accumulation of type I and type III fibrillar collagens occurs throughout the free wall and interventricular septum of patients with primary hypertension and left ventricular hypertrophy (LVH). In the present study the serum concentration of procollagen type III amino terminal peptide (PIIIP) was measured to determine the value of this peptide as a potential marker of ventricular fibrosis in hypertensive patients, particularly those with LVH. The study population consisted of patients with never-treated mild to moderate essential hypertension and 30 normotensive control subjects. Clinical, echocardiographic, electrocardiographic and biochemical parameters were assessed in all patients. Heart rate, body mass index and levels of blood pressure were increased in hypertensives, particularly those with LVH, compared to normotensive controls. Posterior wall thickness, left ventricular (LV) mass and LV mass index, and serum PIIIP concentration were also increased in hypertensives, with significant differences between the two hypertensive groups. The ratio between maximal early and late transmitral flow velocity measured during diastole was lower in hypertensives, particularly those with LVH, than in normotensive controls. The increase in PIIIP indicates that type III collagen synthesis increases in hypertensives, particularly those with LVH, implying that alterations in the heart in hypertension are the result not solely of hypertrophied LV muscle, but also of increased collagen deposition within the ventricular wall and around the coronary vessels. Thus, measurement of serum PIIIP could be a practical and useful tool in the non-invasive assessment of myocardial remodeling in hypertension. Copyright © 2014 Sociedade Portuguesa de Cardiologia. Published by Elsevier España. All rights reserved.

Is Doppler tissue velocity during early left ventricular filling preload independent?

NASA Technical Reports Server (NTRS)

Yalcin, F.; Kaftan, A.; Muderrisoglu, H.; Korkmaz, M. E.; Flachskampf, F.; Garcia, M.; Thomas, J. D.

2002-01-01

BACKGROUND: Transmitral Doppler flow indices are used to evaluate diastolic function. Recently, velocities measured by Doppler tissue imaging have been used as an index of left ventricular relaxation. OBJECTIVE: To determine whether Doppler tissue velocities are influenced by alterations in preload. METHODS: Left ventricular preload was altered in 17 patients (all men, mean (SD) age, 49 (8) years) during echocardiographic measurements of left ventricular end diastolic volume, maximum left atrial area, peak early Doppler filling velocity, and left ventricular myocardial velocities during early filling. Preload altering manoeuvres included Trendelenberg (stage 1), reverse Trendelenberg (stage 2), and amyl nitrate (stage 3). Systolic blood pressure was measured at each stage. RESULTS: In comparison with baseline, left ventricular end diastolic volume (p = 0.001), left atrial area (p = 0.003), peak early mitral Doppler filling velocity (p = 0.01), and systolic blood pressures (p = 0.001) were all changed by preload altering manoeuvres. Only left ventricular myocardial velocity during early filling remained unchanged by these manoeuvres. CONCLUSIONS: In contrast to standard transmitral Doppler filling indices, Doppler tissue early diastolic velocities are not significantly affected by physiological manoeuvres that alter preload. Thus Doppler tissue velocities during early left ventricular diastole may provide a better index of diastolic function in cardiac patients by providing a preload independent assessment of left ventricular filling.

Analysis of Delayed Sea Breeze Onset for Fort Ord Prescribed Burning Operations

DTIC Science & Technology

2015-12-01

Gahmberg et al. (2009) provided additional detail to the synoptic flow through the Coriolis effect . All directions are as seen from the sea with...ambient flows left of the offshore direction providing the strongest opposing winds as Coriolis effects provide additional support in the offshore...support the development of the sea breeze due to Coriolis effects , the mesoscale flow at the surface is quite different. The 1600 UTC through 1900

Venus - Lakshmi Region

NASA Technical Reports Server (NTRS)

1991-01-01

This Magellan image is centered at 55 degrees north latitude, 348.5 degrees longitude, in the eastern Lakshmi region of Venus. This image, which is of an area 300 kilometers (180 miles) in width and 230 kilometers (138 miles) in length, is a mosaic of orbits 458 through 484. The image shows a relatively flat plains region composed of many lava flows. The dark flows mostly likely represent smooth lava flows similar to 'pahoehoe' flows on Earth while the brighter lava flows are rougher flows similar to 'aa' flows on Earth. (The terms 'pahoehoe' and 'aa' refer to textures of lava with pahoehoe a smooth or ropey surface, and aa a rough, clinkery texture). The rougher flows are brighter because the rough surface returns more energy to the radar than the smooth flows. Situated on top of the lava flows are three dark splotches. Because of the thick Venusian atmosphere, the small impactors break up before they reached the surface. Only the fragments from the broken up impactor are deposited on the surface and these fragments produce the dark splotches in this image. The splotch at the far right (east) has a crater centered in it, indicating that the impactor was not completely destroyed during its journey through the atmosphere. The dark splotches in the center and to the far left in this image each represent an impactor that was broken up into small fragments that did not penetrate the surface to produce a crater. The dark splotch at the left has been modified by the wind. A southwest northeast wind flow has moved some of the debris making up the splotch to the northeast where it has piled up against some small ridges.

Percutaneous Direct Puncture Embolization with N-butyl-cyanoacrylate for High-flow Priapism

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tokue, Hiroyuki, E-mail: tokue@s2.dion.ne.jp; Shibuya, Kei; Ueno, Hiroyuki

There are many treatment options in high-flow priapism. Those mentioned most often are watchful waiting, Doppler-guided compression, endovascular highly selective embolization, and surgery. We present a case of high-flow priapism in a 57-year-old man treated by percutaneous direct puncture embolization of a post-traumatic left cavernosal arteriovenous fistula using N-butyl-cyanoacrylate. Erectile function was preserved during a 12-month follow-up. No patients with percutaneous direct puncture embolization for high-flow priapism have been reported previously. Percutaneous direct puncture embolization is a potentially useful and safe method for management of high-flow priapism.

Effect of accessory ostia on maxillary sinus ventilation: a computational fluid dynamics (CFD) study.

PubMed

Zhu, Jian Hua; Lee, Heow Pueh; Lim, Kian Meng; Gordon, Bruce R; Wang, De Yun

2012-08-15

We evaluated, by CFD simulation, effects of accessory ostium (AO) on maxillary sinus ventilation. A three-dimensional nasal model was constructed from an adult CT scan with two left maxillary AOs (sinus I) and one right AO (sinus II), then compared to an identical control model with all AOs sealed (sinuses III and IV). Transient simulations of quiet inspiration and expiration at 15 L/min, and nasal blow at 48 L/min, were calculated for both models using low-Reynolds-number turbulent analysis. At low flows, ventilation rates in sinuses with AOs (I ≈ 0.46 L/min, II ≈ 0.54 L/min), were both more than a magnitude higher than sinuses without AOs (II I ≈ 0.019 L/min, IV ≈ 0.020 L/min). Absence of AO almost completely prevented sinus ventilation. Increased ventilation of sinuses with AOs is complex. Under high flow conditions mimicking nose blowing, in sinuses II, III, and IV, the sinus flow rate increased. In contrast, the airflow direction through sinus I reversed between inspiration and expiration, while it remained almost constant throughout the respiration cycle in sinus II. CFD simulation demonstrated that AOs markedly increase maxillary sinus airflow rates and alter sinus air circulation patterns. Whether these airflow changes impact maxillary sinus physiology or pathophysiology is unknown. Copyright © 2012 Elsevier B.V. All rights reserved.

Left Atrial Appendage Closure for Stroke Prevention: Devices, Techniques, and Efficacy.

PubMed

Iskandar, Sandia; Vacek, James; Lavu, Madhav; Lakkireddy, Dhanunjaya

2016-05-01

Left atrial appendage closure can be performed either surgically or percutaneously. Surgical approaches include direct suture, excision and suture, stapling, and clipping. Percutaneous approaches include endocardial, epicardial, and hybrid endocardial-epicardial techniques. Left atrial appendage anatomy is highly variable and complex; therefore, preprocedural imaging is crucial to determine device selection and sizing, which contribute to procedural success and reduction of complications. Currently, the WATCHMAN is the only device that is approved for left atrial appendage closure in the United States. Copyright © 2016 Elsevier Inc. All rights reserved.

Evaluating the Patient with Left Lower Quadrant Abdominal Pain.

PubMed

Bodmer, Nicholas A; Thakrar, Kiran H

2015-11-01

Left lower quadrant pain is a frequent indication for imaging in the emergency department. Most causes of pain originate from the colon, including diverticulitis, colitis, fecal impaction, and epiploic appendagitis. Left-sided urolithiasis and spontaneous hemorrhage in the retroperitoneum or rectus sheath are additional causes of pain. Computed tomography is the preferred imaging modality in the emergent setting for all of these pathologic conditions. Gynecologic, testicular, and neoplastic pathology may also cause left lower quadrant pain but are not discussed in this article. Copyright © 2015 Elsevier Inc. All rights reserved.

Worms Expelled With the Urine From a Bosniak Cyst III of the Left Kidney.

PubMed

Yang, Jie; Li, Pu; Su, Chuan; Zhang, Jia-Yi; Gu, Min

2016-07-01

An old fishman presented with left lumbago and finding worms in his urine. Type-B ultrasonic inspection and computed tomography scan found a Bosniak cyst III, containing several wire-like elements, in the middle of the left kidney. Expelled worms were confirmed to be Dioctophyma renale. After two courses of albendazole, the man was cured. Copyright © 2016 Elsevier Inc. All rights reserved.

Cilia play a role in breaking left-right symmetry of the sea urchin embryo.

PubMed

Takemoto, Ayumi; Miyamoto, Tatsuo; Simono, Fumie; Kurogi, Nao; Shirae-Kurabayashi, Maki; Awazu, Akinori; Suzuki, Ken-Ichi T; Yamamoto, Takashi; Sakamoto, Naoaki

2016-06-01

Left-right asymmetry of bilaterian animals is established during early development. In mice, frogs and fishes, the ciliated left-right organizer plays an essential role in establishing bilateral asymmetry, and leftward flow of extracellular fluid generated by ciliary motion results in Nodal activity on the left side. However, H(+) /K(+) -ATPase activity is also involved in the determination of left-right asymmetry in a variety of animals, and it has been thought to be an ancestral mechanism in deuterostomes. In sea urchin, the determination of the left-right asymmetry based on H(+) /K(+) -ATPase activity was already clarified, but it remains to be uncovered whether ciliary motion is involved in the left-right asymmetry of the embryo. Here, we show evidence that ciliary motion is involved in the establishment of left-right asymmetry of sea urchin embryo. Furthermore, we show that the initial cilia generated on small micromeres during the early stage of embryogenesis may be involved in this process. These results suggest that the cilia-mediated mechanism for the determination of left-right asymmetry may be acquired at the base of the deuterostomes. © 2016 Molecular Biology Society of Japan and John Wiley & Sons Australia, Ltd.

High Intracranial Pressure Induced Injury in the Healthy Rat Brain.

PubMed

Dai, Xingping; Bragina, Olga; Zhang, Tongsheng; Yang, Yirong; Rao, Gutti R; Bragin, Denis E; Statom, Gloria; Nemoto, Edwin M

2016-08-01

We recently showed that increased intracranial pressure to 50 mm Hg in the healthy rat brain results in microvascular shunt flow characterized by tissue hypoxia, edema, and increased blood-brain barrier permeability. We now determined whether increased intracranial pressure results in neuronal injury by Fluoro-Jade stain and whether changes in cerebral blood flow and cerebral metabolic rate for oxygen suggest nonnutritive microvascular shunt flow. Intracranial pressure was elevated by a reservoir of artificial cerebrospinal fluid connected to the cisterna magna. Arterial blood gases, cerebral arterial-venous oxygen content difference, and cerebral blood flow by MRI were measured. Fluoro-Jade stain neurons were counted in histologic sections of the right and left dorsal and lateral cortices and hippocampus. University laboratory. Male Sprague Dawley rats. Arterial pressure support if needed by IV dopamine infusion and base deficit corrected by sodium bicarbonate. Fluoro-Jade stain neurons increased 2.5- and 5.5-fold at intracranial pressures of 30 and 50 mm Hg and cerebral perfusion pressures of 57 ± 4 (mean ± SEM) and 47 ± 6 mm Hg, respectively (p < 0.001) (highest in the right and left cortices). Voxel frequency histograms of cerebral blood flow showed a pattern consistent with microvascular shunt flow by dispersion to higher cerebral blood flow at high intracranial pressure and decreased cerebral metabolic rate for oxygen. High intracranial pressure likely caused neuronal injury because of a transition from normal capillary flow to nonnutritive microvascular shunt flow resulting in tissue hypoxia and edema, and it is manifest by a reduction in the cerebral metabolic rate for oxygen.

Effect of atrial systole on canine and porcine coronary blood flow.

PubMed

Bellamy, R F

1981-09-01

A feature of phasic coronary flow patterns recorded in conscious chronically instrumented dogs is the atrial cove--a transient depression of arterial flow that occurs during atrial systole. The association between the hemodynamic effects of atrial systole and the atrial cove was studied in anesthetized dogs and pigs with complete heart block. Many atrial coves are available for study in these preparations because atrial activity continues unabated during the diastolic ventricular arrest that follows cessation of electrical pacing. The effect of atrial systole is to translate the pressure-flow relation found during diastole to a higher intercept pressure without change in slope. The increase in the intercept pressure equals the increase in intramyocardial pressure measured with microtransducers embedded in the left ventricular wall. The decrement in flow during the atrial cove is a direct function of the change in intramyocardial pressure and an inverse function of coronary vascular resistance. Each atrial systole is associated with a forward flow transient in the coronary veins, the peak of which occurs at the same instant as does the nadir of atrial flow. These data suggest that the coronary vessels are acting as collapsible tubes and that the waterfall model of the coronary circulation is applicable. The following sequence is proposed to account for the atrial cove. Atrial systole ejects a bolus of blood into the left ventricle increasing both ventricular cavity and intramyocardial pressures. The increase in intramyocardial pressure raises the back pressure opposing coronary flow, reducing the arterial perfusion pressure gradient and causing flow to fall.

Chronic outpatient management of patients with a left ventricular assist device

PubMed Central

Franzwa, Jennifer

2015-01-01

The use of mechanical circulatory support (MCS) as treatment for advanced heart failure (HF) has grown exponentially over the past 15 years. The continuous flow left ventricular assist device (CF-LVAD) has become the most used form of MCS in advanced HF, especially since approval of use as destination therapy (DT) and with the lack of organ availability. Long-term survival has improved and diligent outpatient management is thus particularly critical to achieve optimal outcomes. This review will discuss outpatient management strategies for patients with HF and a left ventricular assist device (LVAD). PMID:26793331

F-16XL Ship #2 during last flight showing titanium laminar flow glove on left wing

NASA Technical Reports Server (NTRS)

1996-01-01

Dryden research pilot Dana Purifoy bends NASA F-16 XL #848 away from the tanker on the 44th flight in the Supersonic Laminar Flow Control program recently. The flight test portion of the program ended with the 45th and last data collection flight from NASA's Dryden Flight Research Center, Edwards, California, on Nov. 26, 1996. The project demonstrated that laminar--or smooth--airflow could be achieved over a major portion of a wing at supersonic speeds. The flight tests at Dryden involved use of a suction system which drew boundary-layer air through millions of tiny laser-drilled holes in a titanium 'glove' that was fitted to the upper surface of the F-16XL's left wing.

New approaches to the Doppler echocardiographic assessment of diastolic function: from research laboratory to clinical practice

NASA Technical Reports Server (NTRS)

Pasquet, A.; Garcia, M. J.; Thomas, J. D.

1999-01-01

Over the past decade, Doppler echocardiography has become a well-established tool for the diagnosis of left ventricular diastolic dysfunction. Unfortunately, in many clinical situations traditional Doppler indices of transmittal and pulmonary venous flow are inconclusive, primarily due to their dependence on left atrial pressure. Recently, new Doppler indices that are much less dependent on preload have been developed, based on intraventricular flow propagation and intrinsic myocardial velocity. These methodologies provide direct assessment of ventricular relaxation and the small intraventricular pressure gradients essential to efficient filling of the ventricle. We review in this article the theoretical and experiment background of these new echo techniques as well as how they can be implemented in routine clinical practice.

Homolateral ataxia and crural paresis: a crossed cerebral-cerebellar diaschisis.

PubMed Central

Giroud, M; Creisson, E; Fayolle, H; Gras, P; Vion, P; Brunotte, F; Dumas, R

1994-01-01

A patient developed weakness of the right leg and homolateral ataxia of the arm, caused by a subcortical infarct in the area supplied by the anterior cerebral artery in the left paracentral region, demonstrated by CT and MRI. Cerebral blood flow studied by technetium-labelled hexamethyl-propylene-amine oxime using single photon emission computed tomography showed decreased blood flow in the left lateral frontal cortex and in the right cerebellar hemisphere ("crossed cerebral-cerebellar diaschisis"). The homolateral ataxia of the arm may be caused by decreased function of the right cerebellar hemisphere, because of a lesion of the corticopontine-cerebellar tracts, whereas crural hemiparesis is caused by a lesion of the upper part of the corona radiata. Images PMID:8126511

Randomized clinical trial studying effects of a personalized supervised lifestyle intervention program on cardiovascular status in physically inactive healthy volunteers

PubMed Central

Westergren, Helena U; Gan, Li-Ming; Månsson, Marianne; Svedlund, Sara

2018-01-01

Background The impact of personalized exercise training and a healthy dietary lifestyle in healthy volunteers on coronary flow reserve and cardiovascular function remains to be investigated in a controlled study setting. Purpose To examine the effects of a Mediterranean-inspired diet combined with regular physical exercise (standard) and a personalized supervised exercise program (DAPS) on coronary flow reserve and cardiovascular function. Results The number of males were 10 (59%) and 9 (47%) and mean age was 54 ± 12 and 55 ± 5 years in standard versus DAPS group, respectively. Primary outcomes were in addition to improved body composition and aerobic capacity, increased TDE-CFR (5.0%, CI:1.62,8.64, p = 0.005) and left ventricle ejection fraction (LVEF) during hyperemia (10.2%, CI:1.62,19.4, p = 0.022) in DAPS adjusted for the control period. Also, plasma fibrinogen decreased (−12.1%, CI:-22.0,–0.92, p = 0.035) in the DAPS group. Secondary outcomes, after adjusting DAPS intervention effects for the standard-training period, TDE-CFR and hyperemic LVEF remained significantly improved. Materials and Methods This randomized, controlled clinical trial (URL: http://www.clinicaltrials.gov NCT02713724) included 36 healthy volunteers who underwent exercise ECG before randomization to standard or DAPS groups. Standard-group was given gym-membership with limited instructions and general dietary advice. DAPS-group received personalized supervised exercise programs and more detailed dietary advice with regular contact with a personal trainer. Effects were evaluated after 3 months. All participants underwent coronary flow reserve by transthoracic ultrasound (TDE-CFR), blood marker analysis and examinations of vascular function. Standard-group was evaluated pre-control, post-control (=pre-intervention) and post-intervention. DAPS-group was examined at pre-intervention and post-intervention. Conclusions A personalized supervised training- and diet program improves cardiovascular status in healthy subjects with a physically inactive lifestyle and may be a promising approach for cardiovascular prevention in the general population. PMID:29507706

Lowering Interleukin-12 Activity Improves Myocardial and Vascular Function Compared With Tumor Necrosis Factor-a Antagonism or Cyclosporine in Psoriasis.

PubMed

Ikonomidis, Ignatios; Papadavid, Evangelia; Makavos, George; Andreadou, Ioanna; Varoudi, Maria; Gravanis, Kostas; Theodoropoulos, Kostas; Pavlidis, George; Triantafyllidi, Helen; Moutsatsou, Paraskevi; Panagiotou, Christina; Parissis, John; Iliodromitis, Efstathios; Lekakis, John; Rigopoulos, Dimitrios

2017-09-01

Interleukin (IL)-12 activity is involved in the pathogenesis of psoriasis and acute coronary syndromes. We investigated the effects of IL-12 inhibition on vascular and left ventricular (LV) function in psoriasis. One hundred fifty psoriasis patients were randomized to receive an anti-IL-12/23 (ustekinumab, n=50), anti-tumor necrosis factor-a (TNF-α; etanercept, n=50), or cyclosporine treatment (n=50). At baseline and 4 months post-treatment, we measured (1) LV global longitudinal strain, twisting, and percent difference between peak twisting and untwisting at mitral valve opening (%untwMVO) using speckle-tracking echocardiography, (2) coronary flow reserve, (3) pulse wave velocity and augmentation index, (4) circulating NT-proBNP (N-terminal pro-B-type natriuretic peptide), TNF-α, IL-6, IL-12, IL-17, malondialdehyde, and fetuin-a. Compared with baseline, all patients had improved global longitudinal strain (median values: -17.7% versus -19.5%), LV twisting (12.4° versus 14°), %untwMVO (27.8% versus 35%), and coronary flow reserve (2.8 versus 3.1) and reduced circulating NT-proBNP, IL-17, TNF-α, and IL-6 post-treatment ( P <0.05). Compared with anti-TNF-α and cyclosporine, anti-IL-12/23 treatment resulted in a greater improvement of global longitudinal strain (25% versus 17% versus 6%,), LV twist (27% versus 17% versus 1%), %untwMVO (31% versus 27% versus 17%), and coronary flow reserve (14% versus 11% versus 4%), as well as a greater reduction of IL-12 (-25% versus -4% versus -2%), malondialdehyde (-27% versus +5% versus +26%), and NT-proBNP(-26% versus -13.6% versus 9.1%) and increase of fetuin-a ( P <0.01). Pulse wave velocity and augmentation index were improved only after anti-IL-12/23 treatment and correlated with changes in global longitudinal strain, LV twisting-untwisting ( P <0.05). In psoriasis, IL-12/23 inhibition results in a greater improvement of coronary, arterial, and myocardial function than TNF-α inhibition or cyclosporine treatment. URL: http://www.clinicaltrials.gov. Unique identifier: NCT02144857. © 2017 American Heart Association, Inc.

Quantitative evaluation improves specificity of myocardial perfusion SPECT in the assessment of functionally significant intermediate coronary artery stenoses: a comparative study with fractional flow reserve measurements.

PubMed

Sahiner, Ilgin; Akdemir, Umit O; Kocaman, Sinan A; Sahinarslan, Asife; Timurkaynak, Timur; Unlu, Mustafa

2013-02-01

Myocardial perfusion SPECT (MPS) is a noninvasive method commonly used for assessment of the hemodynamic significance of intermediate coronary stenoses. Fractional flow reserve (FFR) measurement is a well-validated invasive method used for the evaluation of intermediate stenoses. We aimed to determine the association between MPS and FFR findings in intermediate degree stenoses and evaluate the added value of quantification in MPS. Fifty-eight patients who underwent intracoronary pressure measurement in the catheterization laboratory to assess the physiological significance of intermediate (40-70%) left anterior descending (LAD) artery lesions, and who also underwent stress myocardial perfusion SPECT either for the assessment of an intermediate stenosis or for suspected coronary artery disease were analyzed retrospectively in the study. Quantitative analysis was performed using the 4DMSPECT program, with visual assessment performed by two experienced nuclear medicine physicians blinded to the angiographic findings. Summed stress scores (SSS) and summed difference scores (SDS) in the LAD artery territory according to the 20 segment model were calculated. A summed stress score of ≥ 3 and an SDS of ≥ 2 were assumed as pathologic, indicating significance of the lesion; a cutoff value of 0.75 was used to define abnormal FFR. Both visual and quantitative assessment results were compared with FFR using Chi-square (χ²) test. The mean time interval between two studies was 13 ± 11 days. FFR was normal in 45 and abnormal in 13 patients. Considering the FFR results as the gold standard method for assessing the significance of the lesion, the sensitivity and specificity of quantitative analysis determining the abnormal flow reserve were 85 and 84%, respectively, while visual analysis had a sensitivity of 77% and a specificity of 51%. There was a good agreement between the observers (κ = 0.856). Summed stress and difference scores demonstrated moderate inverse correlations with FFR values (r = -0.542, p < 0.001 and r = -0.506, p < 0.001, respectively). Quantitative analysis of the myocardial perfusion SPECT increases the specificity in evaluating the significance of intermediate degree coronary lesions.