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Sample records for aortic cross clamping

  1. The pathophysiology of aortic cross-clamping.

    PubMed

    Zammert, Martin; Gelman, Simon

    2016-09-01

    During open aortic surgery, interrupting the blood flow through the aorta by applying a cross-clamp is often a key step to allow for surgical repair. As a consequence, ischemia is induced in parts of the body distal to the clamp site. This significant alteration in the blood flow is almost always associated with hemodynamic changes. Upon release of the cross-clamp, the blood flow is restored, triggering an ischemia-reperfusion response, leading to many pathophysiological processes such as inflammation, humoral changes, and metabolite circulation that could lead to injury in many organ systems and may significantly influence the postoperative outcome. It is therefore important to understand these processes and how they can be treated in order to allow for safe surgical aortic repairs while ensuring the best possible outcomes.

  2. Myocardial protection in operations requiring more than 2 h of aortic cross-clamping.

    PubMed

    Bar-El, Y; Adler, Z; Kophit, A; Kertzman, V; Sawaed, S; Ross, A; Cohen, O; Milo, S

    1999-03-01

    Long periods of aortic cross-clamping time during cardiac surgery are associated with high rates of morbidity and mortality because of damage to the myocardium. Recently, we have used a method of myocardial protection based on the principles of hyperkalemic cardioplegic arrest. We use antegrade administration of warm, undiluted blood followed by continuous retrograde infusion of tepid, undiluted blood supplemented with potassium and magnesium. In this study, we have retrospectively reviewed our experience with this method of cardioprotection in operations requiring more than 2 h of cross-clamp time. We retrospectively reviewed the medical records of 1280 patients who underwent myocardial revascularization, valve repair or replacement, or a combination of both operations between January 1, 1994 and December 31, 1997. Patients were divided into two groups: the short cross-clamp group (SXC) (n = 1144) had cross-clamp times < 120 min (mean, 78 +/- 20 min; range, 35-119 min) and the long cross-clamp group (LXC) (n = 136) had cross-clamp times > 120 min (mean, 154 +/- 31 min; range, 120-277 min). We compared preoperative, operative, and postoperative variables between the two groups. Significantly more patients in the long cross-clamp group (43.4%) underwent the combined operation than in the short cross-clamp group (2.3%), and the rate of reoperation was significantly higher in the long cross-clamp group (12%) than in the short cross-clamp group (5%). Despite these differences in operative complexity, we found no difference in hospital mortality rates between the two groups. The only significant postoperative differences were that the long cross-clamp group had a greater need for inotropic agents (43 vs. 29%), higher serum levels of creatine kinase (880 +/- 583 vs. 613 +/- 418) and CK-MB (10.9 +/- 6.4 vs. 5.9 +/- 5.2), and a longer hospital stay (9.6 vs. 6.1 days). Long, complex operations requiring more than 2 h of cross-clamping can be performed safely with our method

  3. Aortic and mitral valve surgery on the beating heart is lowering cardiopulmonary bypass and aortic cross clamp time.

    PubMed

    Gersak, Borut; Sutlic, Zeljko

    2002-01-01

    The concept of cardiac surgery on the beating heart is acceptable rationale for the cardiac surgery in the next millenium. Beating heart (off-pump) coronary artery bypass grafting (CABG) techniques have led us to consider the possibility for performing the aortic and mitral valve surgery (mitral valve repairs and replacements - with or without CABG) on the beating heart with the technique of retrograde oxygenated coronary sinus perfusion. We used the technique of retrograde oxygenated blood coronary sinus perfusion in 78 patients (Group All) - (36 patients were with extremely low ejection fraction (Group X) - 62% of whom were in New York Heart Association (NYHA) class 4 and 34% of whom were in NYHA class 3). The procedures for the patients were: aortic, mitral and tricuspid valve surgery, in combination with CABG in ischemic patients. CABG was done in all the cases off-pump. In addition, we performed a case match study for 37 patients with good ejection fraction (51.65 +/- 11.88) (Beating Heart Group) operated on the beating heart with most appropriate group of patients (No. 37) operated in our institutions on arrested heart (ejection fraction 51.07 +/- 12.93) (Arrested Heart Group). The case match selection criteria were: gender, left ventricular ejection fraction, atrial fibrillation, hypertension, pulmonary hypertension, and diabetes. The selected beating heart group and selected arrested heart groups were without statistically significant differences for the mentioned criteria. There were statistically significant differences between Beating Heart Group and Arrested Heart Group in the duration of Cardiopulmonary Bypass Time (69.35 +/- 13.52 min. versus 93.59 +/- 28.54 min.), p<0.001, and statistically significant differences in Aortic Cross Clamp Time (46.5 +/- 8.95 min. versus 61.5 +/- 18.34 min.), p<0.001. The values for Creatinin Kinase (CK) and LDH were not statistically different, however the absolute values for Beating Heart Group were lower. There was no

  4. Physiologic Responses to Infrarenal Aortic Cross-Clamping during Laparoscopic or Conventional Vascular Surgery in Experimental Animal Model: Comparative Study

    PubMed Central

    Martín-Cancho, María F.; Crisóstomo, Verónica; Soria, Federico; Calles, Carmen; Sánchez-Margallo, Francisco M.; Díaz-Güemes, Idoia; Usón-Gargallo, Jesús

    2008-01-01

    The aim of this study was to compare the hemodynamic and ventilatory effects of prolonged infrarenal aortic cross-clamping in pigs undergoing either laparotomy or laparoscopy. 18 pigs were used for this study. Infrarenal aortic crossclamping was performed for 60 minutes in groups I (laparotomy, n = 6) and II (laparoscopy, n = 6). Group III (laparoscopy, n = 6) underwent a 120-minute long pneumoperitoneum in absence of aortic clamping (sham group). Ventilatory and hemodynamic parameters and renal function were serially determined in all groups. A significant decrease in pH and significant increase in PaCO2 were observed in group II, whereas no changes in these parameters were seen in group I and III. All variables returned to values similar to baseline in groups I and II 60 minutes after declamping. A significant increase in renal resistive index was evidenced during laparoscopy, with significantly higher values seen in Group II. Thus a synergic effect of pneumoperitoneum and aortic cross-clamping was seen in this study. These two factors together cause decreased renal perfusion and acidosis, thus negatively affecting the patient's general state during this type of surgery. PMID:21197458

  5. Design and finite element analysis of a novel smart clamper for aortic cross-clamping in minimally invasive surgery.

    PubMed

    Hajizadeh Farkoush, Siamak; Abolfathi, Nabiollah; Mehmanesh, Hormoz; Najarian, Siamak

    2016-01-01

    Aortic cross-clamping is a critical action during heart surgeries which may cause some injuries to the wall of the artery. These injuries may have both short-term and long-term adverse effects on the artery function. Appropriate clampers can properly occlude the artery and decrease the extent of injury. Thus, developing a model for evaluation of such clampers is inevitable. In this paper, a finite element model of the aorta is presented; then, different mechanisms of clamping are investigated. In this regard, a numerical model of aortic cross-clamping by three types of clampers has been implemented with consideration of nonlinear behavior of two-layer artery, residual stress in aorta, and calcification. These three clamper models are commercial Chitwood clamper and linear mechanism clamper with and without balloon. Using the obtained results, comparative analysis was performed between the proposed clamper design and the commercial one. Based upon the analysis, it was concluded that the designed clamper, linear mechanism clamper with balloon, helps to distribute the stress uniformly in different layers of the aorta, which results in better performance of the clamping procedure and causes less injury in the aorta, especially when there is calcification.

  6. Vascular relaxation of canine visceral arteries after ischemia by means of supraceliac aortic cross-clamping followed by reperfusion

    PubMed Central

    2010-01-01

    Background The supraceliac aortic cross-clamping can be an option to save patients with hipovolemic shock due to abdominal trauma. However, this maneuver is associated with ischemia/reperfusion (I/R) injury strongly related to oxidative stress and reduction of nitric oxide bioavailability. Moreover, several studies demonstrated impairment in relaxation after I/R, but the time course of I/R necessary to induce vascular dysfunction is still controversial. We investigated whether 60 minutes of ischemia followed by 30 minutes of reperfusion do not change the relaxation of visceral arteries nor the plasma and renal levels of malondialdehyde (MDA) and nitrite plus nitrate (NOx). Methods Male mongrel dogs (n = 27) were randomly allocated in one of the three groups: sham (no clamping, n = 9), ischemia (supraceliac aortic cross-clamping for 60 minutes, n = 9), and I/R (60 minutes of ischemia followed by reperfusion for 30 minutes, n = 9). Relaxation of visceral arteries (celiac trunk, renal and superior mesenteric arteries) was studied in organ chambers. MDA and NOx concentrations were determined using a commercially available kit and an ozone-based chemiluminescence assay, respectively. Results Both acetylcholine and calcium ionophore caused relaxation in endothelium-intact rings and no statistical differences were observed among the three groups. Sodium nitroprusside promoted relaxation in endothelium-denuded rings, and there were no inter-group statistical differences. Both plasma and renal concentrations of MDA and NOx showed no significant difference among the groups. Conclusion Supraceliac aortic cross-clamping for 60 minutes alone and followed by 30 minutes of reperfusion did not impair relaxation of canine visceral arteries nor evoke biochemical alterations in plasma or renal tissue. PMID:20642850

  7. Intermittent aortic cross-clamping for isolated CABG can save lives and money: experience with 15307 patients.

    PubMed

    Boethig, D; Minami, K; Lueth, J-U; El-Banayosy, A; Breymann, T; Koerfer, R

    2004-06-01

    The ideal myocardial protection during isolated CABG is still a matter of debate. Cardioplegia versus intermittent aortic cross-clamping (IACC) are the main opponents; the following article shows that IACC can be safe, efficient and might be cheaper than cardioplegia. Demographics and co-morbidities of 15307 CABG only patients consecutively operated on between January 1993 and October 2001 in the Heart Center in Bad Oeynhausen were assessed by the German Quality Assurance data set and risk-stratified using the EuroSCORE. Outcome (30-day or in-hospital mortality) was compared to the expected EuroSCORE estimation. Expected mortality was 3.25 %, observed mortality was 1.3 %, being significantly lower in the low, medium as well as high risk patients subgroup. Complication rates increased steadily with expected mortality rates. Stroke and myocardial infarction rates for patients with peripheral vessel disease were not higher than in comparable studies. More than 1000000 EUR were saved by lower cardioplegia bills. Myocardial protection with intermittent aortic cross-clamping for isolated CABG can be safe, effective, and economically advantageous when compared to cardioplegic solutions.

  8. Aortic cross-clamping and reperfusion in pigs reduces microvascular oxygenation by altered systemic and regional blood flow distribution.

    PubMed

    Siegemund, Martin; van Bommel, Jasper; Stegenga, Michiel E; Studer, Wolfgang; van Iterson, Mat; Annaheim, Sandra; Mebazaa, Alexandre; Ince, Can

    2010-08-01

    In this study, we tested the hypothesis that aortic cross-clamping (ACC) and reperfusion cause distributive alterations of oxygenation and perfusion in the microcirculation of the gut and kidneys despite normal systemic hemodynamics and oxygenation. Fifteen anesthetized pigs were randomized between an ACC group (n = 10), undergoing 45 minutes of aortic clamping above the superior mesenteric artery, and a time-matched sham surgery control group (n = 5). Systemic, intestinal, and renal hemodynamics and oxygenation variables were monitored during 4 hours of reperfusion. Microvascular oxygen partial pressure (microPo(2)) was measured in the intestinal serosa and mucosa and the renal cortex, using the Pd-porphyrin phosphorescence technique. Intestinal luminal Pco(2) was determined by air tonometry and the serosal microvascular flow by orthogonal polarization spectral imaging. Organ blood flow and renal and intestinal microPo(2) decreased significantly during ACC, whereas the intestinal oxygen extraction and Pco(2) gap increased. The intestinal response to reperfusion after ACC was a sustained reactive hyperemia but no such effect was seen in the kidney. Despite a sustained high intestinal O(2) delivery, serosal microPo(2) (median [range], 49 mm Hg [41-67 mm Hg] versus 37 mm Hg [27-41 mm Hg]; P < 0.05 baseline versus 4 hours reperfusion) and the absolute number of perfused microvessels decreased along with an increased intestinal Pco(2) gap (17 mm Hg [10-19 mm Hg] versus 23 mm Hg [19-30 mm Hg]; P < 0.05). In contrast, the kidney showed a progressive O(2) delivery decrease accompanied by a decrease in renal cortex oxygenation (70 mm Hg [52-93 mm Hg] versus 57 mm Hg [33-64 mm Hg]; P < 0.05). Increased systemic and regional blood flow and oxygen supply after ACC does not ensure adequate regional blood flow and microcirculatory oxygenation in all organs.

  9. Avoiding aortic clamping during CABG reduces postoperative stroke

    PubMed Central

    Moss, Emmanuel; Puskas, John D; Thourani, Vinod H; Kilgo, Patrick; Chen, Edward P; Leshnower, Bradley G; Lattouf, Omar M; Guyton, Robert A.; Glas, Kathryn E; Halkos, Michael E.

    2014-01-01

    Objective The purpose of this study was to determine whether the incidence of postoperative stroke (PS) could be reduced by eliminating aortic clamping during CABG. Methods From 2002–2013, 12,079 patients underwent primary, isolated CABG at a single US academic institution. Aortic manipulation was completely avoided by using in-situ internal mammary arteries for inflow in 1,552 (12.9%) patients (no-touch), a clampless facilitating device (CFD) was used for proximal anastomoses in 1,548 (12.8%) patients, and aortic clamping was used in 8,979 (74.3%) patients. These strategies were assessed in a logistic regression model controlling for relevant variables. Results The overall incidence of PS was 1.4% (n=165), with an unadjusted incidence of 0.6% (n=10) in the no-touch group, 1.2% (n=18) in the CFD group, and 1.5% (n=137) in the clamp group (p<0.01 for no-touch vs clamp). The ratio of observed to expected stroke rate increased as the degree of aortic manipulation increased, from 0.48 in the no-touch group, to 0.61 in the CFD group, and 0.95 in the clamp group. Aortic clamping was independently associated with an increase in PS compared to a no-touch technique (AOR 2.50, p<0.01). When separated by CPB utilization, both the off-pump partial clamp and on-pump cross-clamp techniques increased the risk of PS compared to no-touch (AOR 2.52, p<0.01 and AOR 4.25, p<0.001, respectively). Conclusion A no-aortic touch technique has the lowest risk for postoperative stroke for patients undergoing CABG. Clamping the aorta during CABG increases the risk of PS, regardless of the severity of aortic disease. PMID:25293356

  10. A Brief Period of Hypothermia Induced by Total Liquid Ventilation Decreases End-Organ Damage and Multiorgan Failure Induced by Aortic Cross-Clamping.

    PubMed

    Mongardon, Nicolas; Kohlhauer, Matthias; Lidouren, Fanny; Hauet, Thierry; Giraud, Sébastien; Hutin, Alice; Costes, Bruno; Barau, Caroline; Bruneval, Patrick; Micheau, Philippe; Cariou, Alain; Dhonneur, Gilles; Berdeaux, Alain; Ghaleh, Bijan; Tissier, Renaud

    2016-09-01

    In animal models, whole-body cooling reduces end-organ injury after cardiac arrest and other hypoperfusion states. The benefits of cooling in humans, however, are uncertain, possibly because detrimental effects of prolonged cooling may offset any potential benefit. Total liquid ventilation (TLV) provides both ultrafast cooling and rewarming. In previous reports, ultrafast cooling with TLV potently reduced neurological injury after experimental cardiac arrest in animals. We hypothesized that a brief period of rapid cooling and rewarming via TLV could also mitigate multiorgan failure (MOF) after ischemia-reperfusion induced by aortic cross-clamping. Anesthetized rabbits were submitted to 30 minutes of supraceliac aortic cross-clamping followed by 300 minutes of reperfusion. They were allocated either to a normothermic procedure with conventional ventilation (control group) or to hypothermic TLV (33°C) before, during, and after cross-clamping (pre-clamp, per-clamp, and post-clamp groups, respectively). In all TLV groups, hypothermia was maintained for 75 minutes and switched to a rewarming mode before resumption to conventional mechanical ventilation. End points included cardiovascular, renal, liver, and inflammatory parameters measured 300 minutes after reperfusion. In the normothermic (control) group, ischemia-reperfusion injury produced evidence of MOF including severe vasoplegia, low cardiac output, acute kidney injury, and liver failure. In the TLV group, we observed gradual improvements in cardiac output in post-clamp, per-clamp, and pre-clamp groups versus control (53 ± 8, 64 ± 12, and 90 ± 24 vs 36 ± 23 mL/min/kg after 300 minutes of reperfusion, respectively). Liver biomarker levels were also lower in pre-clamp and per-clamp groups versus control. However, acute kidney injury was prevented in pre-clamp, and to a limited extent in per-clamp groups, but not in the post-clamp group. For instance, creatinine clearance was 4.8 ± 3.1 and 0.5 ± 0.6 m

  11. Alterations in cerebrospinal fluid PO(2), PCO(2), and pH measurements during and after experimental thoracic aortic cross-clamping.

    PubMed

    Ulus, Fatma; Hellberg, Anders; Ulus, A Tulga; Karacagil, Sadettin

    2009-01-01

    In a model of aortic cross-clamping, we studied the use of a multiparameter sensor for measurement of cerebrospinal fluid (CSF) PO(2), PCO(2), and pH during and after aortic cross-clamping. The present study addressed the above-mentioned alterations and their relation according to time intervals. In 31 pigs, a sensor was introduced into the intrathecal space and epidural laser Doppler was used to measure spinal cord blood flow (SCF). By placing the aortic clamp at different levels, three different spinal cord ischemia groups were obtained (mild, moderate, and severe). CSF variables with SCF were studied for 25%, 50%, and 100% changes according to baseline level. In the clamping period, SCF decreased 71.5%, 40.0%, and 33.3% in groups 1, 2, and 3, respectively. CSF O(2) tension reached 0 in group 1, decreased 74.8% in group 2, and was 12.7% in group 3. CSF CO(2) tension increased 247.2% and 202.0% in groups 1 and 2, respectively, but slightly increased in group 3. The maximum reaction time of CSF O(2) tension was about 16.7-26.9min, although this range was 34.5-49.8min in CSF CO(2) tension. We recognized that O(2) tension reacts faster than PCO(2) and pH. It is possible for O(2) tension to be used faster than produced CO(2) in the ischemic medium, although it is known that the diffusion rate of CO(2) is much higher. Spinal cord O(2) tension monitoring is an important method to detect ischemic changes.

  12. Remote Ischemic Preconditioning Decreases the Magnitude of Hepatic Ischemia-Reperfusion Injury on a Swine Model of Supraceliac Aortic Cross-Clamping.

    PubMed

    Martikos, G; Kapelouzou, A; Peroulis, M; Paspala, A; Athanasiadis, D; Maheras, A; Liakakos, T D; Moulakakis, K; Vasdekis, S; Lazaris, A M

    2017-09-05

    Temporary hepatic ischemia is inevitable during open aortic surgery when supraceliac clamping is necessary, as in thoracoabdominal or pararenal aneurysms. Remote ischemic preconditioning (RIPC) has been described as a potential protective means against ischemia - reperfusion injury (IRI) in various tissues including the liver. The aim of this experimental study was to detect the effect of RIPC on liver IRI in a model of supraceliac aortic cross-clamping. An animal study was performed. Four groups of 6 swines each were examined: the control (Sham) group, the ischemia-reperfusion (IR) group, and 2 remote ischemic preconditioning groups (RIPC I and RIPC II group). In the IR group, the animals underwent a complete cessation of the splanchnic arterial circulation for 30 min by a concomitant occlusion of the supraceliac and the infrarenal aorta. In the RIPC groups a remote preconditioning was applied before the splanchnic ischemia. This consisted of a temporary occlusion of the infrarenal aorta for 15 min followed by 15 min of reperfusion (RIPC I group), and 3 cycles of 5 min similar ischemia, followed by 5 min of reperfusion each (RIPC II group). All animals were followed for 24 hr after the ischemia (reperfusion period). The liver ischemia-reperfusion injury was assessed by examining specific serum biomarkers indicating the magnitude of metabolic injury from selective blood samples of the hepatic circulation. In particular, the following parameters were examined: C-reactive protein, Interleukin-6, Tumor Necrosis Factor a, Ferritin and L-arginine. All parameters were affected in the IR group as compared to the sham group. Both RIPC groups developed a less serious change as compared to the IR group, in all examined parameters. In an animal study of splanchnic ischemia produced in a way to this produced during a supraceliac aortic aneurysm open repair, the remote ischemic preconditioning seemed to attenuate the effect of hepatic ischemia-reperfusion injury. Remote

  13. Trends in Aortic Clamp Use During Coronary Artery Bypass Surgery: The Effect of Aortic Clamping Strategies on Neurologic Outcomes

    PubMed Central

    Daniel, William T.; Kilgo, Patrick; Puskas, John D.; Thourani, Vinod H.; Lattouf, Omar M.; Guyton, Robert A.; Halkos, Michael E.

    2013-01-01

    Objective The purpose of this study was to determine the impact of different clamping strategies during CABG on the incidence of postoperative stroke. Methods In this case-control study, all patients at Emory hospitals from 2002–2009 with postoperative stroke after isolated CABG (N=141) were matched 1:4 to a contemporaneous cohort of patients without postoperative stroke (N=565). Patients were matched according to the Society of Thoracic Surgeons (STS) Predicted Risk of Postoperative Stroke (PROPS), which is based on 26 variables. On- (ONCAB) and off-pump (OPCAB) patients were matched separately. Multiple logistic regression analysis with adjusted odds ratios (OR) was performed to identify operative variables associated with postoperative stroke. Results Among the ONCAB cohort, the single cross-clamp technique was associated with a decreased risk of stroke compared to the double clamp (cross clamp + partial clamp) technique (OR=0.385, p=0.044). Within the OPCAB cohort, there was no significant difference in stroke according to clamp use. Epiaortic ultrasound of the ascending aorta increased from 45.3% in 2002 to 89.4% in 2009. From 2002–2009, clamp use decreased from 97.7% of cases to 72.7%. Conclusions During ONCAB, the use of a single cross-clamp compared to the double clamp technique decreases the risk of postoperative stroke. The use of any aortic clamp has decreased and epiaortic ultrasound use has increased from 2002–2009, indicating a change in operative technique and surgeon awareness of the potential complications associated with manipulation of the aorta. PMID:23477689

  14. Rewarming Rate of the Myocardium During the Aortic Cross-Clamp Time: Variations with Different Levels of Body Hypothermia

    PubMed Central

    Juffé, Alberto; Burgos, Raul; Montero, Carlos Garcia; Tellez, Gaberiel; Prades, Gonzalo; Lloves, Eduardo; Figuera, Diego

    1985-01-01

    Twenty patients underwent elective cardiac valve replacement at 20° C of body hypothermia. Temperatures of the ventricles of both walls were monitored on 12 different sites. Distribution of myocardial temperature ranged between 24.3 and 29.3° C for patients of Group I before cardioplegia delivery and 13.2° C in the septum after cardioplegic infusion. Average temperatures for the anterior and posterior wall were 13.6 C and 15° C in the left ventricle and 14.7 and 15° C in the right ventricle. Myocardial temperatures ranged from 26 to 28.7° C for patients of Group II. After cardioplegic arrest, septal temperatures averaged 14.9° C. The recorded sites of the anterior and posterior left ventricle were 14.1 and 13.1° C. The effects of rewarming on the different myocardial areas occurred according to a logarithmic equation, which is faster in the first 10 minutes. The data suggest that the myocardium can be adequately protected with 25° C hypothermia when the cross-clamp period is shorter than 60 minutes. When longer ischemic periods are expected, myocardial protection is best accomplished with 20° C hypothermia. PMID:15227003

  15. A stepwise aortic clamp procedure to treat porcelain aorta associated with aortic valve stenosis and hemodialysis.

    PubMed

    Isoda, Susumu; Osako, Motohiko; Kimura, Tamizo; Nishimura, Kenji; Yamanaka, Nozomu; Nakamura, Shingo; Maehara, Tadaaki

    2014-01-01

    A 62-year-old man was referred for an aortic-valve surgery because of severe aortic stenosis. Thirty years ago, he had undergone a mitral valve commissurotomy and after 9 years, the valve had been replaced by a mechanical valve. He had been undergoing hemodialysis for the past 8 years. A computed tomographic (CT) scan of the chest and abdomen showed a dense circumferential calcification in the wall of the entire thoracic and abdominal aorta, pulmonary artery, and left and right atrium. A conventional aortic-valve replacement was performed. To avoid an embolic event, a "stepwise aortic clamp" procedure was attempted and involved the following: (1) brief circulatory arrest and aortotomy during moderate hypothermia; (2) balloon occlusion at the ascending aorta during low-flow cardiopulmonary bypass (CPB); (3) endoarterectomy by using an ultrasonic surgical aspirator to enable aortic cross-clamping; and (4) a cross-clamp reinforced with felt and full-flow CPB. The patient recovered without any thromboembolic events. Using this procedure to treat a porcelain aorta seemed to reduce the time limit and reduced the risk of brain injury during cardiac surgery.

  16. Improvement in cardioplegic perfusion technique in single aortic clamping - initial results

    PubMed Central

    Sobral, Marcelo Luiz Peixoto; dos Santos Júnior, Sérgio Francisco; de Sá, Juliano Cavalcante; Terrazas, Anderson da Silva; Trompieri, Daniel Francisco de Mendonça; de Sousa, Thierry Araújo Nunes; dos Santos, Gilmar Geraldo; Stolf, Noedir Antonio Groppo

    2014-01-01

    Introduction The most common method used for myocardial protection is administering cardioplegic solution in the coronary circulation. Nevertheless, protection may be achieved by intermittent perfusion of the coronary system with patient's own blood. The intermittent perfusion may be performed by multiple sequences of clamping and opening of the aortic clamp or due single clamping and accessory cannulation of the aortic root as in the improved technique proposed in this study, reperfusion without the need for multiple clamping of the aorta. Objective To evaluate the clinical outcome and the occurrence of neurological events in in-hospital patients submitted to myocardial revascularization surgery with the "improved technique" of intermittent perfusion of the aortic root with single clamping. Methods This is a prospective, cross-sectional, observational study that describes a myocardial management technique that consists of intermittent perfusion of the aortic root with single clamping in which 50 patients (mean age 58.5±7.19 years old) have been submitted to the myocardial revasculrization surgery under the proposed technique. Clinical and laboratory variables, pre- and post-surgery, have been assessed. Results The mean peak level of post-surgery CKMB was 51.64±27.10 U/L in the second post-surgery and of troponin I was 3.35±4.39 ng/ml in the fourth post-surgery, within normal limits. No deaths have occurred and one patient presented mild neurological disorder. Hemodynamic monitoring has not indicated any changes. Conclusion The myocardial revascularization surgery by perfusion with the improved technique with intermittent aortic root with single clamping proved to be safe, enabling satisfactory clinical results. PMID:25140473

  17. Clinical results of minimally invasive mitral valve surgery: endoaortic clamp versus external aortic clamp techniques.

    PubMed

    Ius, Fabio; Mazzaro, Enzo; Tursi, Vincenzo; Guzzi, Giorgio; Spagna, Enrico; Vetrugno, Luigi; Bassi, Flavio; Livi, Ugolino

    2009-11-01

    : This study was carried out with the aim of presenting our experience with minimally invasive mitral surgery and compare the endoaortic clamp with the external aortic clamp (EAC) techniques. : Between December 2002 and May 2009, 139 patients (75 men, aged 63 ± 11 years) underwent video-assisted mitral valve surgery through right thoracotomy. Twelve (9%) patients were operated without clamping the aorta, 32 (23%) patients (group A) were operated on by using the endoaortic clamp, and 95 (68%) patients were operated on by using the EAC (group B). There was no significant difference between groups A and B regarding preoperative variables. : Intraoperative procedure-associated problems were experienced in three group A patients (9.3%, two aortic dissections with conversion to sternotomy; one conversion due to bad exposure) and in two group B patients (2%, one conversion to sternotomy for bleeding and one for ascending aorta hematoma). At a mean follow-up of 32 months, 121 patients (97%) were in New York Heart Association class I-II, with satisfactory echocardiographic results. There was one in-hospital and six late deaths (three noncardiac, two cardiac, and one valve related). Five-year actuarial survival was 88% ± 8%. There were three reoperations, one early (<30 days) after complex mitral valve repair, with a 5-year freedom from reoperation of 97% ± 2%. Postoperative levels of myocardial cytonecrosis enzymes as well as the extracorporeal circulation time were significantly lower in group B patients (P < 0.05). : Intraoperative procedure-associated complications with endoclamping combined with an apparently better myocardial protection forced us to change our practice to the more simple and economic EAC technique.

  18. Mechanical properties and biological interaction of aortic clamps: are these all minimally invasive?

    PubMed

    Bianchi, Giacomo; Pucci, Angela; Matteucci, Marco; Varone, Egidio; Romano, Simone Lorenzo; Lionetti, Vincenzo; Glauber, Mattia

    2013-01-01

    Although specifically designed aortic clamps are mainstay of minimally invasive cardiac surgery, so far, no comparative reports about their mechanical properties and interaction with the aortic wall have been reported. In this study, the generated force in the clamps' jaws and the biological response of the aorta after clamping are evaluated. The jaw force of five commercially available clamps [Geister, Cygnet, Cardiovision (CV) 195.10, CV 195.40, and CV 195.83] was assessed by clamping a 2.2-mm compression load cell with a dedicated computer universal serial bus interface at the proximal, the middle, and the distal site from the fulcrum. Biological response of the aortic wall was assessed in five minipigs (weight, 38-40 kg) that underwent thoracic aorta clamping and leakage point test. Immunohistochemistry and morphometric analysis were carried out for each aortic segment tested. Force generation pattern is peculiar of each clamp, being higher in the proximal and the middle portion and lower in the distal part. One clamp (Cygnet) exhibited homogeneous maximal force generation at all three sites. All clamps exhibited peculiar crushing artifacts. A variable degree of endothelial layer disruption occurred in all clamping tests; three clamps (CV 195.10, Cygnet, and Geister) had the lower amount of intact endothelium. The clamping force was not associated with the degree of endothelial disruption (P value was not significant). The choice of a clamp that is not only minimally invasive in design but also least traumatic will help avoid complications of aortic manipulation.

  19. Characterization of renal parenchymal perfusion during experimental infrarenal aortic clamping and declamping with enhanced thermodiffusion electrodes.

    PubMed

    Kraus, T; Mehrabi, A; Angelescu, M; Golling, M; Allenberg, J R; Klar, E

    2001-07-01

    Despite multiple previous experimental and clinical investigations, it has not been fully clarified until now whether infrarenal aortic cross-clamping (IRAC) induces a significant disturbance of renal parenchymal perfusion. Most renal cortical flow data collected thus far have been heterogenous because of inherent limitations of available measurement technology. The enhanced thermal diffusion (TD) electrode is a newly developed and previously validated prototype device that allows continuous quantification of parenchymal kidney perfusion after local probe implantation. We monitored renal perfusion during experimental IRAC with TD for the first time, thereby also evaluating the potential applicability of the method in clinical aortic surgery. IRAC (20 min) followed by sudden declamping was performed in pigs under general anesthesia (n = 14). Renal cortical blood flow (RCBF) was continuously quantified by TD, total aortic flow (TABF) and renal artery flow (RABF) were measured by ultrasonic flow probes, and parameters of systemic circulation were determined by Swan-Ganz catheter. Our results showed that kidney perfusion can be continuously quantified using TD electrodes during experimental aortic surgery in a porcine model. IRAC does not lead to a significant impairment of RCBF in young pigs as measured by TD. Renal perfusion appears to be predominantly pressure driven. Consequently, abrubt aortic declamping can bring about prolonged renal ischemia. Transfer of the TD method to RCBF monitoring during clinical aortic surgery appears to be feasible and should be investigated in selected cases.

  20. Endovascular balloon versus transthoracic aortic clamping for minimally invasive mitral valve surgery: impact on cerebral microemboli.

    PubMed

    Maselli, Daniele; Pizio, Raffaella; Borelli, Gabriele; Musumeci, Francesco

    2006-04-01

    To evaluate micro embolic events occurrence during minimally invasive mitral valve procedures, comparing balloon endovascular aortic occlusion (Group I) and transthoracic aortic clamping technique (Group II), 36 patients (20 in Group I and 16 in Group II) undergoing minimally invasive mitral valve surgery were selected by CT scan and Doppler studies for absence of atherosclerotic disease at aortic, coronary or peripheral level. Assignment to one of the two groups was made on the basis of surgeon's preference. Continuous automated intra-operative transcranial Doppler was used to monitor micro embolic events during five operative steps: cardiopulmonary bypass (CPB) setup, time interval from CPB start until aortic clamp positioning, first minute after clamp-on, first minute after clamp-off, first ten minutes after CPB weaning start. More embolic events were observed in Group II than in Group I (total 143.4+/-30.6 per patient vs. 78.9+/-28.6 per patient). A large amount of embolic events occurring mainly when the aortic clamp was positioned and released accounted for the observed differences. In a low risk population for embolic events occurrence, endovascular balloon aortic clamping determined less embolic signals than transthoracic aortic clamping.

  1. Cardiac and renal responses to cross-clamping of the descending thoracic aorta.

    PubMed

    Roberts, A J; Nora, J D; Hughes, W A; Quintanilla, A P; Ganote, C E; Sanders, J H; Moran, J M; Michaelis, L L

    1983-11-01

    The present study was performed to document the relative efficacy of commonly applied techniques used adjunctively during 1 hour of descending thoracic aortic cross-clamping. Renal and cardiac responses were determined by standard laboratory methods. There were four experimental groups: (1) heparin-bonded shunt; (2) partial femoral-femoral bypass; (3) sodium nitroprusside; (4) control. Each of the experimental groups showed abnormal hemodynamic responses during cross-clamping. Elevations in left ventricular end-diastolic pressure (LVEDP) and systolic blood pressure were common events during clamping, and cardiac output often decreased. Nevertheless, left ventricular performance curves after cross-clamping showed similar increases in left ventricular stroke work (LVSW) with increasing preload. In addition, left ventricular biopsy specimens showed preservation of myocardial high-energy phosphate stores and essentially normal ultrastructural integrity. Radioactive microspheres generally showed increased myocardial blood flow during and after cross-clamping, but no evidence of preferential subendocardial ischemia. Examination of renal function showed a marked decrease in urine output, glomerular filtration rate, and renal plasma flow during cross-clamping. Following the release of the cross-clamp, renal function returned to 50% to 85% of baseline status. Since we could find no major advantage of any of the techniques employed under the present experimental conditions, we suggest that all of the techniques should be part of the surgical armamentarium and the particular preoperative and/or intraoperative findings in a specific case should determine which technique is most appropriate for a given patient.

  2. Thoracic endovascular aortic repair with visceral arteries intermittent clamp technique for descending thoracic aortic aneurysm with shaggy aorta.

    PubMed

    Igarashi, Takashi; Takase, Shinya; Satokawa, Hirono; Misawa, Yukitoki; Wakamatsu, Hiroki; Yokoyama, Hitoshi

    2013-10-01

    Aortic repair for severely atheromatous aneurysm remains a challenge. We used an intermittent clamp technique for all visceral arteries during thoracic endovascular aortic repair (TEVAR) for a thoracic aortic aneurysm with a "shaggy aorta" to prevent systemic thromboembolism. In addition, we applied an extracorporeal circulation circuit to trap the thrombi during the endovascular repair. Postoperatively, no embolic complications were seen, and microscopic examination showed trapped plaques on the filter. We conclude that this technique is an option for preventing thromboembolism in aortic aneurysm repair in the context of a shaggy aorta when substantial concern of distal diffuse atheromatous emboli is raised based on clinical history or clear evidence on imaging.

  3. No Clamp Complete Parachute Technique for Ascending Aorta Anastomosis in Hybrid Aortic Arch Debranching Surgery.

    PubMed

    Chen, I-Ming; Chen, Po-Lin; Chang, Hsiao-Huang

    2017-01-03

    The proper proximal landing zone is a key element for success of endografting in thoracic aortic pathology. If coverage of innominate artery is unavoidable for safe proximal landing, arch debranching surgery is necessary to recruit supra-aortic blood flow before endografting. However, calcified or adhesive ascending aorta makes it difficult to clamp ascending aorta for anastomosis in the first step of arch debranching surgery. We present a novel "no clamp complete parachute technique" to complete this challenging anastomosis. Georg Thieme Verlag KG Stuttgart · New York.

  4. Fatal Delayed Esophageal Rupture Following Aortic Clamping for Treatment of Stanford Type B Dissection

    SciTech Connect

    Ito, Hisao; Yamada, Takayuki; Ishibashi, Tadashi; Akiyama, Masatoshi; Nakame, Takahiko; Ito, Yasuhiro; Konnai, Toshiaki

    2003-11-15

    A 65-year-old man underwent a thromboexclusionoperation for management of chronic Stanford type B dissecting aneurysmin 1991. However, long-term follow-up CT scans after the operation revealed that the ascending aorta gradually enlarged and was eventually complicated by recurrent aortic dissection. The patient complained of frequent bloody sputum, whereas chest roentogenography showed no pulmonary abnormalities. Subsequent swallow esophagogram demonstrated that the upper esophagus was deviated to the right and the middle esophagus was greatly compressed by the aortic clamp. Esophageal endoscopy showed a bloody inner surface and marked swelling of the middle esophagus. The patient eventually died of massive hematemesis in 2001. We describe the imaging features of unanticipated complications such as recurrent dissecting aneurysm or impending esophageal rupture.Furthermore, we discuss the cause of hematemesis and document that the aortic clamp migrated and resulted in development of a recurrent aneurysmal dissection, which in turn resulted in esophageal rupture with aneurysmal disruption.

  5. [Traumatic section of the thoracic aorta: its repair by direct aortic clamping].

    PubMed

    Cairols, M A; Sieyro, F; Miralles, M; Blanes, I; Lozano, P

    1991-01-01

    Traumatic section of descendent aorta, severe complication of a thoracic traumatism, requires an early recognition and restoration because its high mortality rate. Between 1988 and 1990, three patients underwent surgical approach, by direct aortic clamping [correction of clamplaje], at our Service. In two cases, a heart stoppage appeared during the clamping/unclamping [correction of clampaje/desclampaje] maneuvers. One of them had previously electrocardiographic abnormalities, suggestive of heart contusion. Two patients died, one of them during surgical procedure because an irreversible heart stoppage, and the second patient died after 7 days because of a brain hemorrhage. One case presented postoperative paraplegia. Respective rates and literature about the main factors implicated in the diagnosis and treatment of such pathology are reviewed.

  6. Does intermittent cross-clamp fibrillation provide equivalent myocardial protection compared to cardioplegia in patients undergoing bypass graft revascularisation?

    PubMed

    Scarci, Marco; Fallouh, Hazem B; Young, Christopher P; Chambers, David J

    2009-11-01

    A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was: does intermittent cross-clamp fibrillation provide equivalent myocardial protection compared to cardioplegia in patients undergoing bypass graft revascularisation? Altogether, 58 papers were found using the reported search, of which 13 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. We identified 13 studies, of which eight were randomised prospective trials. None of these studies found increased mortality, seven analyzed serum cardiac enzymes and showed that intermittent ischemic arrest provides equal or better protection compared to cardioplegic techniques. Two studies found an increased usage of inotropes and intra aortic balloon pump (IABP) in the intermittent ischemic arrest group. We conclude that intermittent cross-clamp fibrillation is a versatile and cost-effective method of myocardial protection, with the immediate postoperative outcome comparable to cardioplegic arrest in first-time coronary artery bypass graft (CABG). The ischaemic duration associated with intermittent cross-clamp fibrillation is invariably shorter than that associated with cardioplegic arrest, and this may be one explanation for the comparable outcomes. There may also be an element of preconditioning protection during the intermittent cross-clamp fibrillation method, as has been shown experimentally. During elective CABG in patients with no clinical evidence of aortic or cerebro-vascular disease, the incidence of peri-operative microemboli (ME) and postoperative neuropsychological disturbances are shown to be comparable with both techniques of myocardial preservation.

  7. Incidence and Progression of Cardiac Surgery-associated Acute Kidney Injury and its Relationship with Bypass and Cross Clamp Time

    PubMed Central

    Karim, Habib Md Reazaul; Yunus, Mohd; Saikia, Manuj Kumar; Kalita, Jyoti Prasad; Mandal, Mrinal

    2017-01-01

    Introduction: Cardiac surgery-associated kidney injury (CSA-AKI) is common but relatively less is known about its progression. The present study is aimed at evaluating the incidence and course of CSA-AKI and its relationship with the different durations of cardiopulmonary bypass (CPB) and cross clamp times. Materials and Methods: Occurrences of CSA-AKI are evaluated as per the Akin Kidney Injury Network (AKIN) criteria over the course of 5 postoperative day (POD) in 100 patients. The relationship of different durations of CPB and aortic cross clamp time with CSA-AKI is analyzed by Chi-squared test for trend and other appropriate tests using INSTAT software. Results: One hundred (43 male, 57 female; mean age of 37.01 ± 12.28 years, and baseline mean serum creatinine 0.99 ± 0.20 mg %) patients undergone mostly valve replacement, and congenital heart disease correction was evaluated. Nearly 49% suffered CSA-AKI (81.63% AKIN Class I) with maximum numbers on 2nd POD. Serum creatinine followed a falling trend 3rd POD onward except in 8.16% cases of CSA-AKI. Oliguria was absent even in AKIN Class II. The CPB time >70 min and cross clamp time >60 min increase CSA-AKI risk by an OR of 4.76 and 2.84, respectively (P < 0.05). Conclusion: CSA-AKI is very prevalent; mostly of AKIN Class I and increases with increasing CPB and cross clamp time. Urine output is not a reliable indicator of CSA-AKI. The AKIN Class II on the very 1st POD or increasing trend of serum creatinine beyond 3rd POD should alert for early intervention. PMID:28074790

  8. Avoiding Liver Injury with Papaverine and Ascorbic Acid Due to Infrarenal Cross-Clamping: an Experimental Study

    PubMed Central

    Huseyin, Serhat; Guclu, Orkut; Yüksel, Volkan; Erkul, Gulen Sezer Alptekin; Can, Nuray; Turan, Fatma Nesrin; Canbaz, Suat

    2017-01-01

    Objective Ischemia-reperfusion injury after acute ischemia treatment is a serious condition with high mortality and morbidity. Ischemia-reperfusion injury may result in organ failure particularly in kidney, lung, liver, and heart. In our study, we investigated the effects of papaverine and vitamin C on ischemia-reperfusion injury developed in the rat liver after occlusion-reperfusion of rat aorta. Methods 32 Sprague-Dawley female rats were randomized into four groups (n=8). Ischemia was induced with infrarenal aortic cross-clamping for 60 minutes; then the clamp was removed and reperfusion was allowed for 120 minutes. While the control group and the ischemia-reperfusion group did not receive any supplementary agent, two other groups received vitamin C and papaverine hydrochloride (papaverine HCL). Liver tissues were evaluated under the light microscope. Histopathological examination was assessed by Suzuki's criteria and results were compared between groups. Results In ischemia-reperfusion group, severe congestion, severe cytoplasmic vacuolization, and parenchymal necrosis over 60% (score 4) were observed. In vitamin C group, mild congestion, mild cytoplasmic vacuolization and parenchymal necrosis below 30% (score 2) were found. In papaverine group, moderate congestion, moderate cytoplasmic vacuolization and parenchymal necrosis below 60% (score 3) were observed. Conclusion An ischemia of 60 minutes induced on lower extremities causes damaging effects on hepatic tissue. Vitamin C and papaverine are helpful in reducing liver injury after acute ischemia reperfusion and may partially avoid related negative conditions. PMID:28832798

  9. Single-stage repair of aortic coarctation and multiple concomitant cardiac lesions through a median sternotomy.

    PubMed

    Kervan, Umit; Yurdakok, Okan; Genc, Bahadir; Ozen, Anil; Saritas, Ahmet; Kucuker, Seref Alp; Pac, Mustafa

    2013-01-01

    Through a median sternotomy, we performed a single-stage repair of severe aortic coarctation, ventricular septal defect, patent foramen ovale, and mitral valve insufficiency. The severe aortic coarctation was repaired by interposing a synthetic graft between the distal ascending aorta and the descending aorta. We first repaired the coarctation with the 38-year-old man on cardiopulmonary bypass, before aortic cross-clamping, in order to shorten the cross-clamp time.

  10. Intraoperative monitoring during carotid cross-clamping with near-infrared spectroscopy: a preliminary study

    NASA Astrophysics Data System (ADS)

    Ogata, Nobuyoshi; Miyake, Hidenori; Ogata, Kayoko; Wieser, H. G.; Imhof, Hans-Georg; Yonekawa, Yasuhiro

    1996-10-01

    Near-infrared spectroscopy (NIRS) is a noninvasive and real- time method for monitoring oxy-(HbO2) and deoxyhemoglobin (Hb) in tissue, an is suitable for intraoperative monitoring. In this study, NIRS monitoring was performed on 10 patients during carotid cross-clamping. The data were analyzed with a theoretical cerebral hemoglobin model developed to identify an ischemic pattern using NIRS parameters. Temporal profiles of changes in HbO2 and Hb were divided into three phases: initial, second, and last phase. In the initial phase, HbO2 decreased and Hb increased in all the cases. In the second phase, recovery patterns of HbO2 were classified into three groups: complete, incomplete, and on recovery. In the last phase, the HbO2 increased and Hb decreased. Relative changes in HbO2 and Hb measured by NIRS were correlated with changes in blood flow of the internal carotid artery (ICA) measured by a magnetic flowmeter and stump pressure of the internal carotid arteries. The degree of HbO2 decrease in the initial phase was significantly correlated with ICA blood flow before clamping. Three of the 4 patients with ICA stump pressure over 50 mmHg showed a complete recovery pattern in the second phase, while all 4 patients with ICA stump pressure over 50 mmHg showed an incomplete recovery or no recovery pattern with NIRS. These results suggest that NIRS is useful in evaluating changes in cerebral blood flow and the extent of hemodynamic reserve during carotid cross- clamping.

  11. Prenatal diagnosis of a rare aortic arch anomaly with left aortic arch and right ductus arteriosus: Cross ribbon sign

    PubMed Central

    Vijayaraghavan, S Boopathy; Senthil, Sathiya; Latha, K

    2017-01-01

    Here, we report a fetus with a rare aortic arch anomaly with left aortic arch and right ductus arteriosus, which has not been reported so far. In this condition, the aorta extends to the left of the trachea as in normal, while the ductus arteriosus extends to the right of the trachea and joins the descending aorta posterior to the trachea, with a cross-ribbon sign. PMID:28515590

  12. Controlled reperfusion decreased reperfusion induced oxidative stress and evoked inflammatory response in experimental aortic-clamping animal model.

    PubMed

    Jancsó, G; Arató, E; Hardi, P; Nagy, T; Pintér, Ö; Fazekas, G; Gasz, B; Takacs, I; Menyhei, G; Kollar, L; Sínay, L

    2016-09-12

    Revascularization after long term aortic ischaemia in vascular surgery induces reperfusion injury accompanied with oxidative stress and inflammatory responses. The hypothesis of this study was that the aortic occlusion followed by controlled reperfusion (CR) can reduce the ischaemia-reperfusion injury, the systemic and local inflammatory response induced by oxidative stress.Animal model was used. animals underwent a 4-hour infrarenal aortic occlusion followed by continuous reperfusion. Treated group: animals were treated with CR: after a 4-hour infrarenal aortic occlusion we made CR for 30 minutes with the crystalloid reperfusion solution (blood: crystalloid solution ratio 1:1) on pressure 60 Hgmm. Blood samples were collected different times. The developing oxidative stress was detected by the plasma levels of malondialdehyde, reduced glutathion, thiol groups and superoxide dismutase. The inflammatory response was measured by phorbol myristate acetate-induced leukocyte reactive oxygen species production and detection of change in myeloperoxidase levels. The animals were anaesthetized one week after terminating ligation and biopsy was taken from quadriceps muscle and large parenchymal organs.CR significantly reduced the postischaemic oxydative stress and inflammatory responses in early reperfusion period. Pathophysiological results: The rate of affected muscle fibers by degeneration was significantly higher in the untreated animal group. The infiltration of leukocytes in muscle and parenchymal tissues was significantly lower in the treatedgroup.CR can improve outcome after acute lower-limb ischaemia. The results confirm that CR might be also a potential therapeutic approach in vascular surgery against reperfusion injury in acute limb ischaemia. Supported by OTKA K108596.

  13. Antegrade and retrograde perfusion in minimally invasive mitral valve surgery with transthoracic aortic clamping: a single-institution experience with 1632 patients over 12 years.

    PubMed

    Murzi, Michele; Cerillo, Alfredo G; Gasbarri, Tommaso; Margaryan, Rafik; Kallushi, Enkel; Farneti, Pierandrea; Solinas, Marco

    2017-03-01

    The aim of the present study was to evaluate the impact of a retrograde arterial perfusion (RAP) strategy versus an antegrade arterial perfusion (AAP) strategy in a consecutive, large cohort of patients who underwent minimally invasive mitral valve surgery with transthoracic aortic clamping through a right minithoracotomy. Between 2003 and 2015, 1632 consecutive patients underwent first-time minimally invasive mitral valve surgery with transthoracic aortic clamping at our institution; 141 (8.6%) of these patients received retrograde perfusion with femoral artery cannulation, whereas 1421 (91.4%) received antegrade perfusion with ascending aorta cannulation. Logistic regression was used to evaluate outcomes and risk factors for death and stroke between groups. The overall frequency of 30-day mortality was 0.7% (13/1632) and was similar between groups (retrograde arterial perfusion RAP 0.7% vs AAP 0.8%; P  = 0.903). The overall postoperative stroke rate was 1.3% (22/1632). The stroke rate was significantly higher in patients receiving retrograde perfusion (3.5% vs 1.1%; P  = 0.005). Risk factors for death were advanced age (odds ratio (OR) = 1.3; P  = 0.004), mitral valve replacement (OR = 3.9; P  = 0.05), emergent procedure (OR = 3.4; P  = 0.014) and conversion to sternotomy (OR = 3.7; P  = 0.001). Multivariable regression analysis revealed that retrograde perfusion was an independent risk factor for stroke (OR = 3.3; P  = 0.004). Other risk factors were conversion to sternotomy (OR = 12; P  = 0.001), active endocarditis (OR = 5.8; P  = 0.07) and hypercholesterolaemia (OR = 2.4; P  = 0.048). Interaction modelling revealed that the only significant risk factor for a neurological event was the use of retrograde perfusion in patients older than 70 years with an atherosclerotic burden (OR = 6.4; P  = 0.033). Minimally invasive mitral valve procedures can be performed with low morbidity and

  14. Endovascular Repair of Abdominal Aortic Aneurysm in a Patient with Renal Transplant

    SciTech Connect

    Rao, M.; Arya, N. Lee, B.; Hannon, R.J.; Loan, W.; Soong, C.V.

    2004-09-15

    Patients with functioning renal transplant who develop abdominal aortic aneurysm can safely be treated with endovascular repair. Endovascular repair of aneurysm avoids renal ischemia associated with cross-clamping of aorta.

  15. Post clamp

    NASA Technical Reports Server (NTRS)

    Ramsey, John K. (Inventor); Meyn, Erwin H. (Inventor)

    1990-01-01

    A pair of spaced collars are mounted at right angles on a clamp body by retaining rings which enable the collars to rotate with respect to the clamp body. Mounting posts extend through aligned holes in the collars and clamp body. Each collar can be clamped onto the inserted post while the clamp body remains free to rotate about the post and collar. The clamp body is selectively clamped onto each post.

  16. Modified technique for aortic cross-clamping during liver donor procurement.

    PubMed

    Desai, Chirag S; Girlanda, Raffaele; Hawksworth, Jason; Fishbein, Thomas M

    2014-05-01

    Undue tension on the donor vessels during organ procurement is associated with intimal dissection, which can form the nidus for the thrombosis of the hepatic artery (HA) and graft loss. According to the US OPTN database, 143 grafts were discarded in the last 15 yr due to vascular damage during procurement. The most common technique to expose the supraceliac aorta is dissection between the left lateral segment of the liver and the esophagus-stomach. In obese donors, due to restricted space and in pediatric donors where the vessels are very delicate and this space is very small, the replaced or accessory left HA(R/A LHA) is prone to damage if approached conventionally. We describe a technique for the exposure of the supraceliac aorta in which the aorta is approached from the left side behind the gastroesophageal junction that does not require division of the gastrohepatic ligament. From May 2007 to May 2013, 104 liver procurements were performed. Eighty-nine (85.6%) were adults, and 15 (14.4%) were pediatric donors. Twenty-three (22.1%) had R/A LHA. No donor organ suffered any damage. One adult recipient with R/A LHA suffered HA thrombosis not related to it. In summary, this technical modification offers improved safety during cadaveric procurement and increases the ease.

  17. Carotid endarterectomy using a "home-constructed" shunt for patients intolerant to cross-clamping.

    PubMed

    Ugurlucan, Murat; Filik, Muslum Ercument; Caglar, Ilker Murat; Zencirci, Ertugrul; Sayin, Omer Ali; Aydiner, Omer; Yildiz, Yahya; Basaran, Murat; Cicek, Sertac

    2015-03-01

    There is a small minority of patients with occlusive carotid artery disease, who are at high-risk for general anesthesia because of their intolerance to carotid flow blockage, even if only for seconds, without neurologic deficit. Even <30 s of temporary clamping of the carotid arteries to deploy a shunt may prove eventful in this patient group. We define safe carotid endarterectomy after the insertion of a novel shunt that we made from simple medical equipment in this patient population. Among 65 patients who underwent carotid endarterectomy between March 2010 and December 2012, 5 (7.7 %; 3 men and 2 women; age range 56-77 years) could not tolerate carotid clamping. We used an alternative carotid shunt, made by us from simple equipment in our clinic, during surgery for these patients. Two patients had bilateral lesions and the remainder had unilateral disease. The degree of stenosis ranged from 70 to 95 %. Temporary carotid clamping resulted in neurologic events, such as loss of consciousness in all and tremor in one, in <10 s (range, from immediately to 8 s after clamping). Full neurologic function was regained 15-30 s after releasing the clamps. All of the patients tolerated the procedures well with the support of our novel shunt. Shunt flow was adequate in all patients and no neurologic deterioration occurred after carotid clamping. The mean carotid clamp time was 28.11 ± 14.19 min. There was no mortality and all patients were followed up for a mean period of 9.3 ± 3.6 months, uneventfully. An alternative, simple shunt, which is easily constructed in the operating room or clinic, using an angiocatheter, a three-way stopcock, and a serum line can provide adequate cerebral flow and permit safe carotid endarterectomy for those rare patients with carotid artery stenosis, who cannot tolerate even seconds of carotid occlusion.

  18. Immediate conversion to CAS after neurological intolerance at cross-clamping test during CEA: a preliminary experience.

    PubMed

    Guy Bianchi, P; Tolva, V; Dalainas, I; Bertoni, G; Cireni, L; Trimarchi, S; Rampoldi, V; Casana, R

    2012-02-01

    The aim of this preliminary study is to evaluate the feasibility and efficacy of CAS as treatment option to endarterectomy when carotid shunt cannot be used safely. The medical records concerning 469 carotid stenosis treated between January 2006 and December 2009 were retrospectively reviewed, focusing on cross-clamp intolerance during CEA. Patients with cross-clamping intolerance were divided in two groups. Group 1: those that concluded the open procedure with the use of a shunt, and Group 2: those who experience immediate brain intolerance and coma and were immediately converted to an endovascular procedure. Mortality and neurological adverse event rate were compared between shunted CEA and cross-clamping intolerant cases converted into CAS. The secondary end-point was long-term survival. Carotid cross-clamp intolerance occurred in 30 cases (8.7%). CEA with Pruitt-Inahara's shunt was performed in 17 cases with a perioperative neurological adverse event rate of 23.5%. In 13 cases limitations to shunting due to quick onset of coma and/or an unfavorable anatomy were encountered. In these 13 cases the open intervention was immediately converted into endovascular procedure. Technical success was achieved in all the converted to CAS cases (100%), with a perioperative neurological adverse event rate of 7.7% (P=0.35 between the two groups). No significant difference emerges comparing patient's survival between the cases Nevertheless, the small dimension of this survey, immediate conversion to CAS resulted feasible with a lower risk of neurological adverse events if compared to CEA with shunt, and could be considered as an alternative to CEA when carotid shunt cannot be used safely.

  19. Cerebral ischemia during carotid artery cross-clamping: predictive value of phase-contrast magnetic resonance imaging.

    PubMed

    Bagan, Patrick; Vidal, Renaud; Martinod, Emmanuel; Destable, Marie-Dominique; Tremblay, Bruno; Dumas, Jean Luc; Azorin, Jacques F

    2006-11-01

    The goal of this prospective study was to determine the utility of preoperative cerebral magnetic resonance imaging (MRI) in predicting cerebral ischemia during carotid artery cross-clamping for endarterectomy. Between January 2000 and December 2003, a total of 121 patients (95 men, 26 women) underwent three-dimensional phase-contrast MRI to assess collateral function prior to carotid endarterectomy. During regional anesthesia, patients were monitored to detect ischemic events and their timing in relation to cross-clamping and to determine mean intraoperative arterial pressure. These findings were then correlated with the collateral variations observed in the circle of Willis on preoperative MRI. Patients were classified into three groups according to neurological tolerance: normal tolerance (n = 106), immediate severe deficit (n = 9), and late deficit associated with arterial hypotension (n = 6). In the second group, a significant correlation was found between the absence of collateral circulation and neurological deficit (p < .0001). These results indicated that three-dimensional phase-contrast MRI is useful for predicting cerebral ischemia during carotid cross-clamping and selecting indications for shunting. Absence of visible collaterals of the circle of Willis on MRI is significantly predictive of early ischemia and an indication for systematic shunt placement.

  20. Sutureless Medtronic 3f Enable aortic valve replacement in a heavily calcified aortic root.

    PubMed

    Vola, Marco; Fuzellier, Jean-Francois; Kasra, Azarnoush; Morel, Jérôme; Campisi, Salvatore; Ruggeri, Gianvito; Favre, Jean Pierre

    2013-05-01

    The case is reported of a surgical aortic valvular stenosis with a severely calcified ascending aortic root in a 76-year-old woman. The morphology and size of the aortic annulus were unsuitable for transcatheter aortic valve implantation (TAVI); thus, surgery was scheduled. Aortic calcifications allowed a transverse aortotomy 4 cm superior to the sinotubular junction, with a remote endoaortic view of the valve. A Medtronic 3f Enable sutureless bioprosthesis was then implanted after aortic annular decalcification. Sutureless bioprostheses are new tools that promise to reduce technical difficulties and cross-clamp times in minimally invasive aortic valve replacement surgery. In addition, sutureless techniques may have other possible advantages in special circumstances requiring full sternotomy access, such as in the present case.

  1. Sutureless aortic valve replacement

    PubMed Central

    Phan, Kevin

    2015-01-01

    The increasing incidence of aortic stenosis and greater co-morbidities and risk profiles of the contemporary patient population has driven the development of minimally invasive aortic valve surgery and percutaneous transcatheter aortic valve implantation (TAVI) techniques to reduce surgical trauma. Recent technological developments have led to an alternative minimally invasive option which avoids the placement and tying of sutures, known as “sutureless” or rapid deployment aortic valves. Potential advantages for sutureless aortic prostheses include reducing cross-clamp and cardiopulmonary bypass (CPB) duration, facilitating minimally invasive surgery and complex cardiac interventions, whilst maintaining satisfactory hemodynamic outcomes and low paravalvular leak rates. However, given its recent developments, the majority of evidence regarding sutureless aortic valve replacement (SU-AVR) is limited to observational studies and there is a paucity of adequately-powered randomized studies. Recently, the International Valvular Surgery Study Group (IVSSG) has formulated to conduct the Sutureless Projects, set to be the largest international collaborative group to investigate this technology. This keynote lecture will overview the use, the potential advantages, the caveats, and current evidence of sutureless and rapid deployment aortic valve replacement (AVR). PMID:25870807

  2. Aortic compressor for aortic occlusion in hemorrhagic shock.

    PubMed

    Mahoney, B D; Gerdes, D; Roller, B; Ruiz, E

    1984-01-01

    The aortic compressor is a device that allows rapid, simple, immediately reversible occlusion of the thoracic aorta, without the aortic dissection required to use an aortic cross-clamp. We evaluated the aortic compressor in a controlled study using a canine hemorrhagic shock model. Twelve mongrel dogs were exsanguinated to a mean arterial pressure (MAP) of 47 mm Hg and maintained at that level for 20 minutes. At that point, all animals had a left lateral thoracotomy. Six study animals had the thoracic aorta occluded at the diaphragm using the compressor. Five minutes after thoracotomy, with or without occlusion, the shed blood was reinfused. Application of the aortic compressor was the only variable. Use of the aortic compressor led to an immediate and statistically significant doubling of the study animals' MAP. The increased afterload of aortic occlusion did not impair cardiac output. The cardiac index of the study animals rose slightly, while that of the control animals fell. At the same time the compressor prevented blood flow to the abdominal aorta. If the canine model can be extrapolated to human application, then the aortic compressor would be expected to enhance perfusion of the heart and brain during hemorrhagic shock, prevent further arterial blood loss from intra-abdominal injury or ruptured abdominal aortic aneurysm, and preserve already diminished cardiac output. Because the aorta does not need to be dissected out to use the compressor, there is no risk of injury to nearby vascular structures.

  3. Endovascular management of a thoracic aortic disruption following failure of deployment of a parachute.

    PubMed

    Kpodonu, Jacques; Wheatley, Grayson H; Ramaiah, Venkatesh G; Diethrich, Edward B

    2007-12-01

    Traumatic thoracic aortic disruption is a life-threatening lesion associated with a high surgical mortality. Endovascular stent graft repair is a minimal invasive approach that does not require a thoracotomy, aortic cross clamping and cardiopulmonary bypass. We report the use of an endoluminal graft to treat a 58-year-old male, who sustained multiple injuries including thoracic aortic disruption in a sky-diving accident due to failure of deployment of his parachute.

  4. Rigid clamp

    DOEpatents

    Benavides, Gilbert L.; Burt, Jack D.

    1994-01-01

    The invention relates to a clamp mechanism that can be used to attach or temporarily support objects inside of tubular goods. The clamp mechanism can also be modified so that it grips objects. The clamp has a self-centering feature to accommodate out-of-roundness or other internal defections in tubular objects such as pipe. A plurality of clamping shoes are expanded by a linkage which is preferably powered by a motor to contact the inside of a pipe. The motion can be reversed and jaw elements can be connected to the linkage so as to bring the jaws together to grab an object.

  5. Rigid clamp

    DOEpatents

    Benavides, G.L.; Burt, J.D.

    1994-07-12

    The invention relates to a clamp mechanism that can be used to attach or temporarily support objects inside of tubular goods. The clamp mechanism can also be modified so that it grips objects. The clamp has a self-centering feature to accommodate out-of-roundness or other internal defections in tubular objects such as pipe. A plurality of clamping shoes are expanded by a linkage which is preferably powered by a motor to contact the inside of a pipe. The motion can be reversed and jaw elements can be connected to the linkage so as to bring the jaws together to grab an object. 12 figs.

  6. [Late paraparesis as a postoperative complication in a patient undergoing the repair of a double aortic aneurysm].

    PubMed

    Bonome González, C; Alvarez Refojo, F; Fernández Carballal, F; Rodríguez Alvarez, R

    1993-01-01

    We report a case of a fifty-seven (57)-years old man undergoing elective surgery of a thoracoabdominal and aortoiliac aneurysm in a single surgical time. The patients is operated undergoing general anesthetic combined with thoracic epidural blockade, and it was done two aortic cross-clamping: one to five cm of the aortic arch and the other to the infrarenal level. The most important intraoperative complications were during the thoracic aortic cross-clamping and the most important postoperative complication was related 48 hours later, to paraparesis after a hypotension episode what improved with rehabilitation treatment.

  7. Are we cross-matching too much blood for elective open abdominal aortic aneurysm repair?

    PubMed Central

    Lowe, Emily; Quarmby, John

    2017-01-01

    Objectives: This study aims to identify current blood transfusion requirements in elective open abdominal aortic aneurysm repair and to compare this to an existing maximum surgical blood order schedule. Methods: We retrospectively identified patients who underwent elective open abdominal aortic aneurysm repair over a 40-month period in our institution. Pre-operative number of units cross-matched and the number of units actually transfused were identified. The cross-match to transfusion ratio was then calculated. Results: Blood transfusion at any time post-operatively was required in 23 (48.9%) cases. Patients needing an intra-operative blood transfusion had a median of 2 units. Of the pre-operative cross-matched units (123), only 43 were used, giving a cross-match to transfusion ratio of 2.86. Conclusion: Our current maximum surgical blood order schedule is poorly followed and a cross-match to transfusion ratio of 2.86 indicates we are cross-matching too many units for elective open abdominal aortic aneurysm repair. A carefully considered individualised management of blood products, with the requirement of at least a valid group and save sample, may be more appropriate. PMID:28228951

  8. [MINIMALLY INVASIVE AORTIC VALVE REPLACEMENT].

    PubMed

    Tabata, Minoru

    2016-03-01

    Minimally invasive aortic valve replacement (MIAVR) is defined as aortic valve replacement avoiding full sternotomy. Common approaches include a partial sternotomy right thoracotomy, and a parasternal approach. MIAVR has been shown to have advantages over conventional AVR such as shorter length of stay and smaller amount of blood transfusion and better cosmesis. However, it is also known to have disadvantages such as longer cardiopulmonary bypass and aortic cross-clamp times and potential complications related to peripheral cannulation. Appropriate patient selection is very important. Since the procedure is more complex than conventional AVR, more intensive teamwork in the operating room is essential. Additionally, a team approach during postoperative management is critical to maximize the benefits of MIAVR.

  9. A clampless and sutureless aortic anastomosis technique using an endograft connector for aortoiliac occlusive disease in which the aorta cannot be clamped or sewn due to calcification or scarring.

    PubMed

    Papadimitriou, Dimitrios; Mayer, Dieter; Lachat, Mario; Pecoraro, Felice; Frauenfelder, Thomas; Pfammatter, Thomas; Ueda, Hideki; Donas, Konstantinos; Veith, Frank J; Rancic, Zoran

    2012-10-01

    Bypass surgery in aortoiliac or aortofemoral occlusive disease can be technically demanding and hazardous due to huge calcifications and/or patient co-morbidities. We report about mid-term results of a telescoping sutureless aortic anastomosis technique using endografts as connectors to address such challenging situations. This is a single-center experience (2004-2011) in seven patients (63 ± 6 years) requiring aortoiliac (three) or aortofemoral (four) bypass surgery. In six cases, an aortic stent graft was telescoped into the infrarenal aorta and partly deployed within the aorta and partly outside the aorta. In the first case, a bifurcated stent graft was deployed and the iliac legs were prolonged extra-anatomically with surgical grafts to reach the femoral bifurcation. In the following five cases, a tapered tubular stent graft was deployed through the aortic wall, landing inside a bifurcated surgical graft that was extra-anatomically connected to the iliac or femoral arteries. In the last case, which presented a hostile abdomen and high-risk for extensive surgery, a similar technique was used, but on the iliac artery level. In that case, an iliac stent graft re-loaded 'upside down' was deployed through the left common iliac wall, landing distally inside a hand-made 10 × 10 mm bifurcated surgical graft that was extra-anatomically connected to the left external iliac artery and to the right femoral artery. The distal anastomoses on the seven cases were performed either with running sutures (ten) or with VORTEC (four). Telescoping aortic and/or iliac anastomosis was successful in all patients. There was no perioperative mortality. One patient developed postoperative hyperperfusion of the left leg and necessitated fasciotomy. During a mean follow-up of 1.8 ± 2 years (minimum: 270 days, maximum: 7.1 years), all of the grafts remained patent and there was neither stent-graft migration nor stenosis on the level of the aortic or iliofemoral connection. One patient

  10. Charlie's Clamp.

    ERIC Educational Resources Information Center

    Tarino, Janet Z.

    1998-01-01

    Presents a version of the crush-the-can demonstration which is a hands-on activity in which students use an inexpensive, easily made holder for the can called Charlie's clamp. Includes some suggestions for the follow-up discussion. (DDR)

  11. Abdominal Aortic Surgery: Anesthetic Implications

    PubMed Central

    Cunningham, Anthony J.

    1991-01-01

    The objectives of the review are to highlight the clinical characteristics of the patient population; to assess multivariate risk factor analysis and the invasive/non-invasive techniques available for risk factor identification and management in this high-risk surgical population; to assess the major hemodynamic, metabolic, and regional blood flow changes associated with aortic cross-clamping/unclamping procedures and techniques for their modification or attenuation; and to assess the influence of perioperative anesthetic techniques and management on patient outcome. PMID:1814052

  12. Selective aortic arch perfusion enables to avoid deep hypothermic circulatory arrest for extirpation of renal cell carcinoma with tumour thrombus extension into the right atrium.

    PubMed

    Zacek, Pavel; Dominik, Jan; Brodak, Milos; Louda, Miroslav

    2014-04-01

    Renal cell carcinoma with a tumour thrombus extending into the right heart chambers necessitates extensive combined urological and cardiac surgery. Maximum safety and exactness in extirpation of the caval and intracardiac thrombus is achieved under deep hypothermic circulatory arrest, at a price of its non-physiological burden and time constraints. We propose a simple surgical manoeuvre enabling selective arch perfusion allowing for a milder hypothermia and liberal interval of circulatory arrest. On a routine cardiopulmonary bypass via median sternotomy, the dissection is extended along the aortic arch to identify the origins of the supra-aortic vessels. After standard aortic cross-clamping and cardioplegic cardiac arrest at moderate hypothermia, a second cross-clamp is applied at the aortic arch beyond the left carotid artery. A selective closed aortic arch perfusion is started while the extirpation of the tumour thrombus from the right atriotomy and abdominal cavotomy is being performed under conditions of circulatory arrest. Using selective aortic arch perfusion, successful and uncomplicated extirpation of voluminous caval and intracardiac tumour thrombi was accomplished in 3 presented patients. Unexpectedly difficult thrombus adhering to hepatic veins in 1 patient required 42 min of circulatory arrest. Postoperative courses were uneventful in all 3 patients. Second aortic cross-clamp to start selective closed aortic arch perfusion provides excellent surgical control of the operative field over a liberal time interval during circulatory arrest under milder hypothermia.

  13. Growing cava vein anastomosis: comparison of cross-clamping and suture times using VCS metallic clips, interrupted nonabsorbable, or continuous absorbable suturing techniques.

    PubMed

    Calles-Vázquez, Mari Carmen; Abellán Rubio, Elena; Ayala, Verónica Crisóstomo; Usón Gargallo, Jesús; Sánchez Margallo, Francisco Miguel

    2013-10-01

    The latest generation in titanium clip application systems, the AnastoClip Vessel Closure System (VCS; LeMaitre Vascular, Burlington, MA), allows surgeons to perform vascular anastomosis more easily and faster than conventional sutures. This system may become the option of choice for vascular reconstruction in pediatric surgery where, as in the case transplant surgery, decreasing vascular occlusion times may influence outcome. The aim of this study was to determine whether VCS metallic clips would allow shorter anastomosis times than conventional interrupted polypropylene or running polyglycolic acid suturing in end-to-end anastomosis performed in the abdominal cava of young pigs. Thirty-two domestic swine, 45 days old, were used for this study. All animals were subjected to an end-to-end anastomosis in the abdominal cava. VCS clips are easier to use for the surgeon, significantly decreasing cross-clamping time in caval anastomosis (VCS 10.33 ± 1.75 min vs. interrupted polypropylene sutures 46.00 ± 6.16 min vs. continuous polyglycolic acid sutures 18.16 ± 1.47 min). VCS clips significantly decrease the time needed for performing an end-to-end anastomosis in the abdominal cava, decreasing cross-clamping time when compared to interrupted polypropylene or running polyglycolic acid sutures. Copyright © 2013 Elsevier Inc. All rights reserved.

  14. Endovascular Abdominal Aortic Aneurysm Repair by Means of the Chimney Technique in a Patient with Crossed Fused Renal Ectopia

    PubMed Central

    Kfoury, Elias; Almanfi, Abdelkader; Dougherty, Kathryn G.

    2016-01-01

    Crossed fused renal ectopia, a congenital anomaly in 1 of 7,000 individuals, presents a challenge during endovascular treatment of abdominal aortic aneurysm. Most treatment approaches in these patients have involved open surgical repair of the aneurysm or endovascular repair with coverage of the ectopic renal artery. We present what we think is the first case of endovascular abdominal aortic aneurysm repair with use of the chimney technique (parallel stent-grafting) to preserve an ectopic renal artery, in an 88-year-old man who was at high risk for open surgery. In addition to the patient's case, we discuss the relevant medical literature. PMID:27303239

  15. Minimally invasive "pocket incision" aortic valve surgery.

    PubMed

    Yakub, M A; Pau, K K; Awang, Y

    1999-02-01

    A minimally invasive approach to aortic valve surgery through a transverse incision ("pocket incision") at the right second intercostal space was examined. Sixteen patients with a mean age of 30 years underwent this approach. The third costal cartilage was either excised (n = 5) or dislocated (n = 11). The right internal mammary artery was preserved. Cardiopulmonary bypass (CPB) was established with aortic-right atrial cannulation in all except the first case. Aortic valve replacements (AVR) were performed in 15 patients and one had aortic valve repair with concomitant ventricular septal defect closure. There was no mortality and no major complications. The aortic cross-clamp, CPB and operative times were 72 +/- 19 mins, 105 +/- 26 mins and 3 hrs 00 min +/- 29 mins respectively. The mean time to extubation was 5.7 +/- 4.0 hrs, ICU stay of 27 +/- 9 hrs and postoperative hospital stay of 5.1 +/- 1.2 days. Minimally invasive "pocket incision" aortic valve surgery is technically feasible and safe. It has the advantages of central cannulation for CPB, preservation of the internal mammary artery and avoiding sternotomy. This approach is cosmetically acceptable and allows rapid patient recovery.

  16. Centrifugal pump support for distal aortic perfusion during repair of traumatic thoracic aortic injury.

    PubMed

    Walls, Joseph T; Curtis, Jack J; McKenney-Knox, Charlotte A; Schmaltz, Richard A

    2002-11-01

    Paraplegia from ischemic injury of the spinal cord and renal failure from inadequate perfusion of the kidneys may occur from aortic cross-clamping during repair of traumatic thoracic aortic injuries. After Institutional Review Board approval, we retrospectively reviewed the charts of 26 patients surgically treated for traumatic transection of the descending thoracic aorta during a 14 year period (1987-2001), using centrifugal pump (Sarns) support for distal aortic perfusion. The study group comprised 19 males and 7 females, whose ages ranged from 15 to 69 years. For all but 1 patient, who fell from a flagpole, the injuries were incurred in motor vehicle accidents. Aortic cross-clamp time lasted between 5 to 78 min (median = 40 min). Mean arterial pressure ranged from 50 to 80 mm Hg (median = 70 mm Hg). All patients survived operation without developing paraplegia or renal failure. Distal centrifugal pump perfusion during repair of traumatic injury of the descending thoracic aorta is a valuable adjunct during surgical treatment and aids in preservation of spinal cord and renal function.

  17. Clamp usable as jig and lifting clamp

    DOEpatents

    Tsuyama, Yoshizo

    1976-01-01

    There is provided a clamp which is well suited for use as a lifting clamp for lifting and moving materials of assembly in a shipyard, etc. and as a pulling jig in welding and other operations. The clamp comprises a clamp body including a shackle for engagement with a pulling device and a slot for receiving an article, and a pair of jaws provided on the leg portions of the clamp body on the opposite sides of the slot to grip the article in the slot, one of said jaws consisting of a screw rod and the other jaw consisting of a swivel jaw with a spherical surface, whereby when the article clamped in the slot by the pair of jaws tends to slide in any direction with respect to the clamp body, the article is more positively gripped by the pair of jaws.

  18. Studying the flow dynamics in an aortic endograft with crossed-limbs.

    PubMed

    Georgakarakos, Efstratios; Xenakis, Antonios; Manopoulos, Christos; Georgiadis, George S; Argyriou, Christos; Tsangaris, Sokrates; Lazarides, Miltos K

    2014-01-01

    To evaluate the flow phenomena within an aortic endograft with crossed-limbs, comparing to an endograft with the ordinary limb bifurcation. An endograft model with crossed-limbs was computationally reconstructed based on Computed Tomography patient-specific data, using commercially available software. Accordingly, its analogue model was reconstructed in the ordinary fashion (ordinary bifurcation). Computational fluid dynamics analysis was performed to determine and compare the flow fields, velocity profiles, pressure and shear stress distribution throughout the different parts of both endograft configurations, in different phases of the cardiac cycle. The flow patterns between the "Ballerina" and the classic endograft were similar, with flow disturbance near the inlet zone at late diastole and smooth flow patterns during the systolic phase. Both configurations presented similar pressure distribution patterns throughout the cardiac cycle. The highest and lowest pressures were demonstrated in the inlet-main body area and the iliac limbs, respectively. Marked differences were observed in the velocity profiles of the proximal limb segments between the two configurations, mostly in the peak- and end-systolic phase. The regions of lower velocities correlated well to low shear values. Differences in the shear stress distribution were noted between the two configurations in the systolic and, predominantly, in the diastolic phase. There are differences in the velocity profiles and shear distribution between the limbs of the two endograft configurations. The pathophysiologic implication of our findings and their possible association with clinical events, such as thrombus apposition, deserves further investigation.

  19. Selective cerebral perfusion with aortic cannulation and short-term hypothermic circulatory arrest in aortic arch reconstruction.

    PubMed

    Turkoz, R; Saritas, B; Ozker, E; Vuran, C; Yoruker, U; Balci, S; Altun, D; Turkoz, A

    2014-01-01

    The deep hypothermic circulatory arrest (DHCA) technique has been used in aortic arch and isthmus hypoplasia for many years. However, with the demonstration of the deleterious effects of prolonged DHCA, selective cerebral perfusion (SCP) has started to be used in aortic arch repair. For SCP, perfusion via the innominate artery route is generally preferred (either direct innominate artery cannulation or re-routing of the cannula in the aorta is used). Herein, we describe our technique and the result of arch reconstruction in combination with selective cerebral and myocardial perfusion (SCMP) and short-term total circulatory arrest (TCA) (5-10 min) through ascending aortic cannulation. Thirty-seven cases with aortic arch and isthmus hypoplasia accompanying cardiac defects were operated on with SCMP and short TCA in Baskent University Istanbul Research and Training Hospital between January 2007 and Sep 2012. There were 17 cases with ventricular septal defect (VSD)-coarctation with aortic arch hypoplasia (CoAAH), 4 cases of transposition of the great arteries-VSD-CoAAH, 4 cases of Taussing Bing Anomaly-CoAAH, 2 cases complete atrioventricular canal defect-CoAAH, 3 cases single ventricle-CoAAH, 3 cases of type A interruption-VSD, 2 subvalvular aortic stenosis-CoAAH and 2 cases of isolated CoAAH. The aorta was cannulated in the middle of the ascending aorta in all cases. The cross-clamp was applied to the aortic arch distal to either the innominate artery or the left carotid artery. In addition, a side-biting clamp was applied to the descending aorta. The aorta between these two clamps was reconstructed with gluteraldehyde-treated autogeneous pericardium, using SCMP. The proximal arch and distal ascending aorta reconstructions were carried out under short TCA. The mean age of the patients was 2.5 ± 2 months. The mean cardiopulmonary bypass and cross-clamp times were 144 ± 58 and 43 ± 27 minutes, respectively. The mean SCMP and descending aorta ischemia times were 22

  20. Arch-first technique via clamshell incision: successful surgical reoperation for aortic arch dissection.

    PubMed

    Ozkara, Ahmet; Cetin, Gurkan; Mert, Murat; Akinci, Okan; Erdem, Can Caglar; Suzer, Kaya

    2005-01-01

    We report a case of successful reoperation for aortic arch dissection with use of the "arch-first" technique in a patient who had Marfan syndrome. Extracorporeal circulation was initiated via right subclavian artery cannulation, and the chest was entered through a clamshell incision for the best exposure. When the patient was cooled to 18 degrees C, the perfusion was stopped. After the 1st aortic arch anastomosis to a 30-mm Dacron graft, cerebral perfusion was reestablished via the right subclavian artery. The aortic repair was then completed. The cerebral ischemic time was 18 minutes, the aortic cross-clamp time was 69 minutes, and the total extracorporeal circulation time was 334 minutes. The patient was discharged from the hospital on postoperative day 10 with no neurologic impairment. The arch-first technique shortens the duration of brain ischemia. When combined with a clamshell incision, the technique is particularly helpful for reoperation of the aortic arch and thoracic aorta.

  1. Aortic angiography

    MedlinePlus

    ... problem with the aorta or its branches, including: Aortic aneurysm Aortic dissection Congenital (present from birth) problems AV ... Mean Abnormal results may be due to: Abdominal aortic aneurysm Aortic dissection Aortic regurgitation Aortic stenosis Congenital (present ...

  2. Modeling and computational analysis of the hemodynamic effects of crossing the limbs in an aortic endograft ("ballerina" position).

    PubMed

    Georgakarakos, Efstratios; Xenakis, Antonios; Manopoulos, Christos; Georgiadis, George S; Tsangaris, Sokrates; Lazarides, Miltos K

    2012-08-01

    To evaluate the displacement forces acting on an aortic endograft when the iliac limbs are crossed ("ballerina" position). An endograft model was computationally reconstructed based on data from a patient whose infrarenal aortic aneurysm had an endovascular stent-graft implanted with the iliac limbs crossed. Computational fluid dynamics analysis determined the maximum displacement force on the endograft and separately on the bifurcation and iliac limbs. Its analogue model was reconstructed for comparison, assuming the neck, main body, and total length constant but considering the iliac limbs to be deployed in the usual bifurcated mode. Calculations were repeated after developing "idealized" models of both the bifurcated and crossed-limbs endografts with straight main bodies and no neck angulation or curved iliac segments. The vector of the total force was directed anterocaudal for both the typical bifurcated and the crossed-limbs configurations, with the forces in the latter slightly reduced and the vertical component accounting for most of the force in both configurations. Idealized crossed-limbs and bifurcated configurations differed only in the force on the iliac limbs, but this difference disappeared in the realistic models. Crossing of the iliac limbs can slightly affect the direction of the displacement forces. Although this configuration can exert larger forces on the limbs than in the bifurcated mode, this effect can be blunted by concomitant modifications in the geometry of the main body and other parts of the endograft, making its hemodynamic behavior resemble that of a typically positioned endograft.

  3. Force-Measuring Clamps

    NASA Technical Reports Server (NTRS)

    Nunnelee, Mark

    2003-01-01

    Force-measuring clamps have been invented to facilitate and simplify the task of measuring the forces or pressures applied to clamped parts. There is a critical need to measure clamping forces or pressures in some applications for example, while bonding sensors to substrates or while clamping any sensitive or delicate parts. Many manufacturers of adhesives and sensors recommend clamping at specific pressures while bonding sensors or during adhesive bonding between parts in general. In the absence of a force-measuring clamp, measurement of clamping force can be cumbersome at best because of the need for additional load sensors and load-indicating equipment. One prior method of measuring clamping force involved the use of load washers or miniature load cells in combination with external power sources and load-indicating equipment. Calibrated spring clamps have also been used. Load washers and miniature load cells constitute additional clamped parts in load paths and can add to the destabilizing effects of loading mechanisms. Spring clamps can lose calibration quickly through weakening of the springs and are limited to the maximum forces that the springs can apply. The basic principle of a force-measuring clamp can be implemented on a clamp of almost any size and can enable measurement of a force of almost any magnitude. No external equipment is needed because the component(s) for transducing the clamping force and the circuitry for supplying power, conditioning the output of the transducers, and displaying the measurement value are all housed on the clamp. In other words, a force-measuring clamp is a complete force-application and force-measurement system all in one package. The advantage of unitary packaging of such a system is that it becomes possible to apply the desired clamping force or pressure with precision and ease.

  4. Quality of life after aortic valve repair is similar to Ross patients and superior to mechanical valve replacement: a cross-sectional study.

    PubMed

    Zacek, Pavel; Holubec, T; Vobornik, M; Dominik, J; Takkenberg, J; Harrer, J; Vojacek, J

    2016-04-02

    In patients after aortic valve surgery, the quality of life is hypothesized to be influenced by the type of the valve procedure. A cross-sectional study on the postoperative quality of life was carried out in patients after aortic valve-sparing surgery (with regards to the age of the patient), Ross procedure and mechanical aortic valve replacement. Quality of life was studied in 139 patients after aortic valve surgery divided into four study groups (Y - aortic valve-sparing procedure at the age below 50 years, mean age 36.2 years; O - aortic valve-sparing procedure at the age 50 years and over, mean age 59.2 years; R - Ross procedure, mean age 37.8 years and M - mechanical aortic valve replacement at the age below 50 years, mean age 39.2 years). SF-36 Short Form and valve-specific questionnaires were mailed to the patients after 6 months or later following surgery (median 26.9 months). In SF-36, the younger aortic valve repair patients and the Ross patients scored significantly better in 4 of 4 physical subscales and in 2 of 4 mental subscales than the older aortic valve repair and mechanical valve replacement patients. In the valve-specific questionnaire; however, all 3 groups free of anticoagulation (Y, O, and R) displayed greater freedom from negative valve-related concerns. Postoperative quality of life is influenced by the type of aortic valve procedure and is negatively linked with mechanical prosthesis implantation and long-term anticoagulation. Aortic valve-sparing strategy should be considered in cases with suitable valve morphology due to favorable clinical results and beneficial impact on the long-term quality of life.

  5. Force-Measuring Clamp

    NASA Technical Reports Server (NTRS)

    Nunnelee, Mark (Inventor)

    2004-01-01

    A precision clamp that accurately measures force over a wide range of conditions is described. Using a full bridge or other strain gage configuration. the elastic deformation of the clamp is measured or detected by the strain gages. Thc strain gages transmit a signal that corresponds to the degree of stress upon the clamp. Thc strain gage signal is converted to a numeric display. Calibration is achieved by ero and span potentiometers which enable accurate measurements by the force-measuring clamp.

  6. Force-Measuring Clamp

    NASA Technical Reports Server (NTRS)

    Nunnelee, Mark (Inventor)

    2004-01-01

    A precision clamp that accurately measures force over a wide range of conditions is described. Using a full bridge or other strain gage configuration. the elastic deformation of the clamp is measured or detected by the strain gages. Thc strain gages transmit a signal that corresponds to the degree of stress upon the clamp. Thc strain gage signal is converted to a numeric display. Calibration is achieved by ero and span potentiometers which enable accurate measurements by the force-measuring clamp.

  7. Photovoltaic panel clamp

    SciTech Connect

    Mittan, Margaret Birmingham; Miros, Robert H. J.; Brown, Malcolm P; Stancel, Robert

    2012-06-05

    A photovoltaic panel clamp includes an upper and lower section. The interface between the assembled clamp halves and the module edge is filled by a flexible gasket material, such as EPDM rubber. The gasket preferably has small, finger like protrusions that allow for easy insertion onto the module edge while being reversed makes it more difficult to remove them from the module once installed. The clamp includes mounting posts or an integral axle to engage a bracket. The clamp also may include a locking tongue to secure the clamp to a bracket.

  8. Photovoltaic panel clamp

    SciTech Connect

    Brown, Malcolm P.; Mittan, Margaret Birmingham; Miros, Robert H. J.; Stancel, Robert

    2013-03-19

    A photovoltaic panel clamp includes an upper and lower section. The interface between the assembled clamp halves and the module edge is filled by a flexible gasket material, such as EPDM rubber. The gasket preferably has small, finger like protrusions that allow for easy insertion onto the module edge while being reversed makes it more difficult to remove them from the module once installed. The clamp includes mounting posts or an integral axle to engage a bracket. The clamp also may include a locking tongue to secure the clamp to a bracket.

  9. Clamping in Boltzmann machines.

    PubMed

    Livesey, M

    1991-01-01

    A certain assumption that appears in the proof of correctness of the standard Boltzmann machine learning procedure is investigated. The assumption, called the clamping assumption, concerns the behavior of a Boltzmann machine when some of its units are clamped to a fixed state. It is argued that the clamping assumption is essentially an assertion of the time reversibility of a certain Markov chain underlying the behavior of the Boltzmann machine. As such, the clamping assumption is generally false, though it is certainly true of the Boltzmann machines themselves. The author also considers how the concept of the Boltzmann machine may be generalized while retaining the validity of the clamping assumption.

  10. The impact of surgical strategy on survival after repair of type A aortic dissection.

    PubMed

    Lawton, Jennifer S; Liu, Jingxia; Kulshrestha, Kevin; Moon, Marc R; Damiano, Ralph J; Maniar, Hersh; Pasque, Michael K

    2015-08-01

    A diverse group of operative strategies are utilized for treatment of acute Stanford type A aortic dissection. We hypothesized that a surgical strategy to prevent cross-clamp injury or false lumen pressurization would be associated with reduced morbidity, mortality, persistent false lumen patency, and improved survival. This study was designed to determine the differences in outcomes between operative techniques. Outcomes and postoperative imaging were compared in patients who underwent surgery for acute type A aortic dissection. Two groups were compared, based on operative strategy. The surgical strategy for group 1 consisted of no aortic cross-clamp use, use of deep hypothermic circulatory arrest, and use of only antegrade perfusion after aortic replacement. The surgical strategy for group 2 consisted of any other combination that lacked 1 of these 3 technical steps. Between January 1, 1996, and December 31, 2012, a total of 196 patients underwent surgery for acute type A aortic dissection. Operative mortality and postoperative morbidity were not statistically different between groups. Mean follow-up time was 3.95 (range: 0-15.4) years. Persistence of a false lumen was not statistically different between groups (P = .78). Overall survival was significantly better in group 1, versus group 2 (P = .0020). Multivariate Cox regression identified preoperative renal failure, chronic lung disease, greater number of packed red blood cells transfused, and being in group 2 as risk factors for poor long-term survival. The operative strategy of group 1 (no cross-clamp, use of DHCA and antegrade perfusion) was associated with a highly significant improvement in survival, despite a lack of statistical difference in the incidence of persistent false aortic lumen between groups. Copyright © 2015 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

  11. Sutureless Aortic Prosthesis Implantation: the First Brazilian Experience with Perceval Device

    PubMed Central

    Tagliari, Ana Paula; de Moura, Leandro; Dussin, Luiz Henrique; Saadi, Eduardo Keller

    2016-01-01

    This is a report of the first Brazilian experience with the Perceval sutureless aortic prosthesis in two patients with severe aortic stenosis. Transesophageal echocardiography was used during the procedure. The aortotomy was performed 1 cm above the sinotubular junction, followed by leaflets removal and decalcification. Correct valve size was selected, device released and an accommodation balloon used. The cardiopulmonary bypass times were 47 and 38 min and the cross-clamp times were 38 and 30 min. There was a significant decrease in mean gradients (41 and 75 mmHg preoperatively; 7 and 8 mmHg postoperatively). There was no major complication or paravalvular leak. PMID:27849308

  12. Retrograde coronary sinus versus aortic root perfusion with cold cardioplegia: randomized study of levels of cardiac enzymes in 40 patients

    SciTech Connect

    Guiraudon, G.M.; Campbell, C.S.; McLellan, D.G.; Kostuk, W.J.; Purves, P.D.; MacDonald, J.L.; Cleland, A.G.; Tadros, N.B.

    1986-11-01

    Myocardial injury was assessed with the use of enzyme indexes in 40 patients randomly assigned to one of two groups undergoing coronary artery bypass surgery. Twenty patients received cold cardioplegia delivered by retrograde coronary sinus perfusion and 20 received cardioplegic solution by anterograde aortic root perfusion. Creatine kinase isoenzyme MB and lactate dehydrogenese isoenzyme 1 and isoenzyme 2 assays were carried out on blood samples obtained from the coronary sinus before aortic cross-clamping and 0, 5, and 30 min after aortic unclamping. Levels of these enzymes were also obtained from venous blood samples before aortic cross-clamping and 3, 8, 14, and 20 hr after aortic unclamping and 2, 3, 4, and 5 days after surgery. Preoperative and postoperative hemodynamic measurements (Swan-Ganz catheter) and radionuclide wall motion studies were also obtained for comparison. There was no overall significant difference between the two groups postoperatively in terms of enzyme indexes, hemodynamic measurements, or results of wall motion studies. We conclude that retrograde coronary sinus perfusion is an alternative to aortic root perfusion in delivering cold cardioplegia. More studies are required to determine which subgroup of patients with coronary artery disease may benefit from retrograde coronary perfusion.

  13. Abdominal aortic aneurysm repair in a patient with a congenital solitary pelvic kidney. A case report.

    PubMed

    Murakami, T; Makino, Y; Suto, Y; Yasuda, K

    2004-10-01

    Abdominal aortic aneurysm (AAA) is rarely associated witha congenital pelvic kidney. To date only 11 cases have been reported in the literature in which a solitary pelvic' kidney was associated in only 1 patient. Repair of thesaneurysm is technically demanding because the abnormal origin of the renal arteries presents the problem of renal ischemia duringaortic cross-clamping. We report a case of a 77-year-old man who was found to have an AAA associated with a congenital solitary pelvic kidney. An abdominal aortography dearly showed 2 aberrant renal arteries, one of which originated from the aortic wall just above the aortic bifurcation and the other from the left common iliac artery. At surgery, we found other associated anomalies including malrotation of the gut and a left undescended testis. The surgical procedure consisted of an aneurysmorrhaphy followed by a tube graft replacement with therenal arteries being left intact to the distal aortic wall or below. Renal preservation during aortic cross-clamping was achieved by direct perfusion of the upper renal artery with cold lactated Ringer's solution together with topical cooling with ice slush. The patient's postoperative course was uneventful. Urinary output was satisfactory and serum creatinine level remained unchanged throughout his hospital stay. The renal preservation method used in this case was simple and effective.

  14. Radial wedge flange clamp

    DOEpatents

    Smith, Karl H.

    2002-01-01

    A radial wedge flange clamp comprising a pair of flanges each comprising a plurality of peripheral flat wedge facets having flat wedge surfaces and opposed and mating flat surfaces attached to or otherwise engaged with two elements to be joined and including a series of generally U-shaped wedge clamps each having flat wedge interior surfaces and engaging one pair of said peripheral flat wedge facets. Each of said generally U-shaped wedge clamps has in its opposing extremities apertures for the tangential insertion of bolts to apply uniform radial force to said wedge clamps when assembled about said wedge segments.

  15. Aortic Cross-Sectional Area/Height Ratio and Outcomes in Patients With a Trileaflet Aortic Valve and a Dilated Aorta.

    PubMed

    Masri, Ahmad; Kalahasti, Vidyasagar; Svensson, Lars G; Roselli, Eric E; Johnston, Douglas; Hammer, Donald; Schoenhagen, Paul; Griffin, Brian P; Desai, Milind Y

    2016-11-29

    In patients with a dilated proximal ascending aorta and trileaflet aortic valve, we aimed to assess (1) factors independently associated with increased long-term mortality and (2) the incremental prognostic utility of indexing aortic root to patient height. We studied consecutive patients with a dilated aortic root (≥4 cm) that underwent echocardiography and gated contrast-enhanced thoracic aortic computed tomography or magnetic resonance angiography between 2003 and 2007. A ratio of aortic root area over height was calculated (cm(2)/m) on tomography, and a cutoff of 10 cm(2)/m was chosen as abnormal, on the basis of previous reports. All-cause death was recorded. The cohort comprised 771 patients (63 years [interquartile range, 53-71], 87% men, 85% hypertension, 51% hyperlipidemia, 56% smokers). Inherited aortopathies, moderate to severe aortic regurgitation, and severe aortic stenosis were seen in 7%, 18%, and 2%, whereas 91% and 54% were on β-blockers and angiotensin-converting enzyme inhibitors, respectively. Aortic root area/height ratio was ≥10 cm(2)/m in 24%. The Society of Thoracic Surgeons score and right ventricular systolic pressure were 3.3±3 and 31±7 mm Hg, respectively. At 7.8 years (interquartile range, 6.6-8.9), 280 (36%) patients underwent aortic surgery (76% within 1 year) and 130 (17%) died (1% in-hospital postoperative mortality). A lower proportion of patients in the surgical (versus nonsurgical) group died (13% versus 19%, P<0.01). On multivariable Cox proportional hazard analysis, aortic root area/height ratio (hazard ratio, 4.04; 95% confidence interval [CI], 2.69-6.231) was associated with death, whereas aortic surgery (hazard ratio, 0.47; 95% CI, 0.27-0.81) was associated with improved survival (both P<0.01). For longer-term mortality, the addition of aortic root area/height ratio ≥10 cm(2)/m to a clinical model (Society of Thoracic Surgeons score, inherited aortopathies, hypertension, hyperlipidemia, medications, aortic

  16. Aortic Dissection

    MedlinePlus

    ... arteries (atherosclerosis) Weakened and bulging artery (pre-existing aortic aneurysm) An aortic valve defect (bicuspid aortic valve) A ... valve, tell your doctor. If you have an aortic aneurysm, find out how often you need monitoring and ...

  17. Quick action clamp

    NASA Technical Reports Server (NTRS)

    Calco, Frank S. (Inventor)

    1991-01-01

    A quick release toggle clamp that utilizes a spring that requires a deliberate positive action for disengagement is presented. The clamp has a sliding bolt that provides a latching mechanism. The bolt is moved by a handle that tends to remain in an engaged position while under tension.

  18. Thoracoabdominal aortic replacement for Crawford extent II aneurysm after thoracic endovascular aortic repair

    PubMed Central

    Hu, Haiou; Zheng, Tie; Zhu, Junming; Liu, Yongmin; Qi, Ruidong

    2017-01-01

    Background The surgical treatment of Crawford extent II aneurysms after thoracic endovascular aortic repair (TEVAR) remains challenging, because of the need to remove the failed endograft and the complexity of the aortic reconstruction. We retrospectively reviewed our experience with surgical management of Crawford extent II aneurysms after TEVAR using thoracoabdominal aortic replacement (TAAR). Methods Eleven patients (10 males, 1 female) with Crawford extent II aneurysm after TEVAR were treated with TAAR between August 2012 and May 2015. The indications included: diameter >5.0 cm; persistent pain; size increase >0.5 cm/year; and no suitable landing zone for re-TEVAR. Five patients underwent surgery under deep hypothermic cardiac arrest, two under mild hypothermic cardiopulmonary bypass, and four under direct aortic cross-clamping under normothermia. Two patients had Marfan syndrome. Results There were no in-hospital deaths. Continuous renal replacement therapy was required in three patients. One patient needed re-intubation, and two patients had prolonged intubation (>72 h). One patient sustained paraplegia after surgery but recovered during follow-up. Cerebrospinal fluid drainage were used in four patients (3 immediately in the operation room, and 1 in the intensive care unit when the patient suffered paraplegia). One patient died during follow-up. Conclusions TAAR represents a feasible option for the treatment of Crawford extent II aneurysms after TEVAR, with acceptable surgical risks and favorable results. PMID:28203407

  19. [Late reoperations after repaired Stanford type A aortic dissection].

    PubMed

    Huang, F H; Li, L P; Su, C H; Qin, W; Xu, M; Wang, L M; Jiang, Y S; Qiu, Z B; Xiao, L Q; Zhang, C; Shi, H W; Chen, X

    2017-04-01

    Objective: To summarize the experience of reoperations on patients who had late complications related to previous aortic surgery for Stanford type A dissection. Methods: From August 2008 to October 2016, 14 patients (10 male and 4 female patients) who underwent previous cardiac surgery for Stanford type A aortic dissection accepted reoperations on the late complications at Department of Thoracic and Cardiovascular Surgery, Nanjing Hospital Affiliated to Nanjing Medical University. The range of age was from 41 to 76 years, the mean age was (57±12) years. In these patients, first time operations were ascending aorta replacement procedure in 3 patients, ascending aorta combined with partial aortic arch replacement in 4 patients, aortic root replacement (Bentall) associated with Marfan syndrome in 3 patients, aortic valve combined with ascending aorta replacement (Wheat) in 1 patient, ascending aorta combined with Sun's procedure in 1 patient, Wheat combined with Sun's procedure in 1 patient, Bentall combined with Sun's procedure in 1 patient. The interval between two operations averaged 0.3 to 10.0 years with a mean of (4.8±3.1) years. The reasons for reoperations included part anastomotic split, aortic valve insufficiency, false aneurysm formation, enlargement of remant aortal and false cavity. The selection of reoperation included anastomotic repair, aortic valve replacement, total arch replacement and Sun's procedure. Results: Of the 14 patients, the cardiopulmonary bypass times were 107 to 409 minutes with a mean of (204±51) minutes, cross clamp times were 60 to 212 minutes with a mean of (108±35) minutes, selective cerebral perfusion times were 16 to 38 minutes with a mean of (21±11) minutes. All patients survived from the operation, one patient died from severe pulmonary infection 50 days after operation. Three patients had postoperative complications, including acute renal failure of 2 patients and pulmonary infection of 1 patient, and these patients were

  20. Physiologic Tolerance of Descending Thoracic Aortic Balloon Occlusion in a Swine Model of Hemorrhagic Shock

    DTIC Science & Technology

    2013-01-10

    Endovascular proximal control of ruptured abdominal aortic aneurysms : the internal aortic clamp. J Cardiovasc Surg (Torino) 2009;50(3):381. 14. Arthurs Z...Starnes B, See C, Andersen C. Clamp Before You Cut: Proximal Control of Ruptured Abdominal Aortic Aneurysms Using Endovascular Balloon Occlusion...PHYSIOLOGIC TOLERANCE OF DESCENDING THORACIC AORTIC BALLOON OCCLUSION IN A SWINE MODEL OF HEMORRHAGIC SHOCK 10 January 2013 Reporting Period: September

  1. A monogenean without clamps

    USDA-ARS?s Scientific Manuscript database

    Ectoparasites face a daily challenge: to remain attached to their host. Polyopisthocotylean monogeneans attach to the surface of fish gills by highly specialized structures, the sclerotized clamps. In the original description of the protomicrocotylid species Lethacotyle fijiensis, described 50 years...

  2. Laser beam guard clamps

    DOEpatents

    Dickson, Richard K.

    2010-09-07

    A quick insert and release laser beam guard panel clamping apparatus having a base plate mountable on an optical table, a first jaw affixed to the base plate, and a spring-loaded second jaw slidably carried by the base plate to exert a clamping force. The first and second jaws each having a face acutely angled relative to the other face to form a V-shaped, open channel mouth, which enables wedge-action jaw separation by and subsequent clamping of a laser beam guard panel inserted through the open channel mouth. Preferably, the clamping apparatus also includes a support structure having an open slot aperture which is positioned over and parallel with the open channel mouth.

  3. Sperm Patch-Clamp

    PubMed Central

    Lishko, Polina; Clapham, David E.; Navarro, Betsy; Kirichok, Yuriy

    2014-01-01

    Sperm intracellular pH and calcium concentration ([Ca2+]i) are two central factors that control sperm activity within the female reproductive tract. As such, the ion channels of the sperm plasma membrane that alter intracellular sperm [Ca2+] and pH play important roles in sperm physiology and the process of fertilization. Indeed, sperm ion channels regulate sperm motility, control sperm chemotaxis toward the egg in some species, and may trigger the acrosome reaction. Until recently, our understanding of these important molecules was rudimentary due to the inability to patch-clamp spermatozoa and directly record the activity of these ion channels under voltage clamp. Recently, we overcame this technical barrier and developed a method for reproducible application of the patch-clamp technique to mouse and human spermatozoa. This chapter covers important aspects of application of the patch-clamp technique to spermatozoa, such as selection of the electrophysiological equipment, isolation of spermatozoa for patch-clamp experiments, formation of the gigaohm seal with spermatozoa, and transition into the whole-cell mode of recording. We also discuss potential pitfalls in application of the patch-clamp technique to flagellar ion channels. PMID:23522465

  4. Aortic valve replacement in geriatric patients with small aortic roots: are sutureless valves the future? †

    PubMed Central

    Shrestha, Malakh; Maeding, Ilona; Höffler, Klaus; Koigeldiyev, Nurbol; Marsch, Georg; Siemeni, Thierry; Fleissner, Felix; Haverich, Axel

    2013-01-01

    OBJECTIVES Aortic valve replacement (AVR) in geriatric patients (>75 years) with small aortic roots is a challenge. Patient–prosthesis mismatch and the long cross-clamp time necessary for stentless valves or root enlargement are matters of concern. We compared the results of AVR with sutureless valves (Sorin Perceval), against those with conventional biological valves. METHODS Between April 2007 and December 2012, 120 isolated AVRs were performed in patients with a small annulus (<22 mm) at our centre. In 70 patients (68 females, age 77.4 ± 5.5 years), conventional valves (C group) and in 50 patients (47 females, age 79.8 ± 4.5 years), sutureless valves (P group) were implanted. The Logistic EuroSCORE of the C group was 16.7 ± 10.4 and that of the P group 20.4 ± 10.7, (P = 0.054). Minimal-access surgery was performed in 4.3% (3/70) patients in the C group and 72% (36/50) patients in the P group. RESULTS The cardiopulmonary bypass (CPB) and cross-clamp times of the C group were 75.3 ± 23 and 50.3 ± 14.2 min vs 58.7 ± 20.9 and 30.1 ± 9 min in the P group, (P < 0.001). In the C group, two annulus enlargements were performed. Thirty-day mortality was 4.3% (n = 3) in the C group and 0 in the P group, (n.s.). At follow-up (up to 5 years), mortalities were 17.4% (n = 12) in the C group and 14% (n = 7) in the P group, (n.s.). CONCLUSIONS This study highlights the advantages of sutureless valves for geriatric patients with small aortic roots reflected by shorter cross-clamp and CPB times, even though most of these patients were operated on via a minimally invasive access. Moreover, due to the absence of a sewing ring, these valves are also almost stentless, with greater effective orifice area (EOA) for any given size. This may potentially result in better haemodynamics even without the root enlargement. This is of advantage, as several studies have shown that aortic root enlargement can significantly increase the risks of AVR. Moreover, as seen in this series

  5. Aortic valve replacement in geriatric patients with small aortic roots: are sutureless valves the future?

    PubMed

    Shrestha, Malakh; Maeding, Ilona; Höffler, Klaus; Koigeldiyev, Nurbol; Marsch, Georg; Siemeni, Thierry; Fleissner, Felix; Haverich, Axel

    2013-11-01

    Aortic valve replacement (AVR) in geriatric patients (>75 years) with small aortic roots is a challenge. Patient-prosthesis mismatch and the long cross-clamp time necessary for stentless valves or root enlargement are matters of concern. We compared the results of AVR with sutureless valves (Sorin Perceval), against those with conventional biological valves. Between April 2007 and December 2012, 120 isolated AVRs were performed in patients with a small annulus (<22 mm) at our centre. In 70 patients (68 females, age 77.4 ± 5.5 years), conventional valves (C group) and in 50 patients (47 females, age 79.8 ± 4.5 years), sutureless valves (P group) were implanted. The Logistic EuroSCORE of the C group was 16.7 ± 10.4 and that of the P group 20.4 ± 10.7, (P = 0.054). Minimal-access surgery was performed in 4.3% (3/70) patients in the C group and 72% (36/50) patients in the P group. The cardiopulmonary bypass (CPB) and cross-clamp times of the C group were 75.3 ± 23 and 50.3 ± 14.2 min vs 58.7 ± 20.9 and 30.1 ± 9 min in the P group, (P < 0.001). In the C group, two annulus enlargements were performed. Thirty-day mortality was 4.3% (n = 3) in the C group and 0 in the P group, (n.s.). At follow-up (up to 5 years), mortalities were 17.4% (n = 12) in the C group and 14% (n = 7) in the P group, (n.s.). This study highlights the advantages of sutureless valves for geriatric patients with small aortic roots reflected by shorter cross-clamp and CPB times, even though most of these patients were operated on via a minimally invasive access. Moreover, due to the absence of a sewing ring, these valves are also almost stentless, with greater effective orifice area (EOA) for any given size. This may potentially result in better haemodynamics even without the root enlargement. This is of advantage, as several studies have shown that aortic root enlargement can significantly increase the risks of AVR. Moreover, as seen in this series, these valves may also enable a broader

  6. [Inflammatory abdominal aortic aneurysm].

    PubMed

    Ziaja, K; Sedlak, L; Urbanek, T; Kostyra, J; Ludyga, T

    2000-01-01

    The reported incidence of inflammatory abdominal aortic aneurysm (IAAA) is from 2% to 14% of patients with abdominal aortic aneurysm and the etiology of this disease is still discussed--according to the literature several pathogenic theories have been proposed. From 1992 to 1997 32 patients with IAAA were operated on. The patients were mostly symptomatic--abdominal pain was present in 68.75% cases, back pain in 31.25%, fever in 12.5% and weight loss in 6.25% of the operated patients. In all the patients ultrasound examination was performed, in 4 patients CT and in 3 cases urography. All the patients were operated on and characteristic signs of inflammatory abdominal aortic aneurysm like: thickened aortic wall, perianeurysmal infiltration or retroperitoneal fibrosis with involvement of retroperitoneal structures were found. In all cases surgery was performed using transperitoneal approach; in three cases intraoperatively contiguous abdominal organs were injured, which was connected with their involvement into periaortic inflammation. In 4 cases clamping of the aorta was done at the level of the diaphragmatic hiatus. 3 patients (9.37%) died (one patient with ruptured abdominal aortic aneurysm). Authors present diagnostic procedures and the differences in the surgical tactic, emphasizing the necessity of the surgical therapy in patients with inflammatory abdominal aortic aneurysm.

  7. From overshoot to voltage clamp.

    PubMed

    Huxley, Andrew

    2002-11-01

    In 1939, A.L. Hodgkin and I found that the nerve action potential shows an "overshoot"--that is, the interior of the fibre becomes electrically positive during an action potential. In 1948, we did our first experiments with a voltage clamp to investigate the current-voltage relations of the nerve membrane. Between those dates, we spent much time speculating about the mechanism by which ions cross the membrane and how the action potential is generated. This article summarizes these speculations, none of which has been previously published.

  8. Minimally Invasive Versus Conventional Aortic Valve Replacement

    PubMed Central

    Attia, Rizwan Q.; Hickey, Graeme L.; Grant, Stuart W.; Bridgewater, Ben; Roxburgh, James C.; Kumar, Pankaj; Ridley, Paul; Bhabra, Moninder; Millner, Russell W. J.; Athanasiou, Thanos; Casula, Roberto; Chukwuemka, Andrew; Pillay, Thasee; Young, Christopher P.

    2016-01-01

    Objective Minimally invasive aortic valve replacement (MIAVR) has been demonstrated as a safe and effective option but remains underused. We aimed to evaluate outcomes of isolated MIAVR compared with conventional aortic valve replacement (CAVR). Methods Data from The National Institute for Cardiovascular Outcomes Research (NICOR) were analyzed at seven volunteer centers (2006–2012). Primary outcomes were in-hospital mortality and midterm survival. Secondary outcomes were postoperative length of stay as well as cumulative bypass and cross-clamp times. Propensity modeling with matched cohort analysis was used. Results Of 307 consecutive MIAVR patients, 151 (49%) were performed during the last 2 years of study with a continued increase in numbers. The 307 MIAVR patients were matched on a 1:1 ratio. In the matched CAVR group, there was no statistically significant difference in in-hospital mortality [MIAVR, 4/307,(1.3%); 95% confidence interval (CI), 0.4%–3.4% vs CAVR, 6/307 (2.0%); 95% CI, 0.8%–4.3%; P = 0.752]. One-year survival rates in the MIAVR and CAVR groups were 94.4% and 94.6%, respectively. There was no statistically significant difference in midterm survival (P = 0.677; hazard ratio, 0.90; 95% CI, 0.56–1.46). Median postoperative length of stay was lower in the MIAVR patients by 1 day (P = 0.009). The mean cumulative bypass time (94.8 vs 91.3 minutes; P = 0.333) and cross-clamp time (74.6 vs 68.4 minutes; P = 0.006) were longer in the MIAVR group; however, this was significant only in the cross-clamp time comparison. Conclusions Minimally invasive aortic valve replacement is a safe alternative to CAVR with respect to operative and 1-year mortality and is associated with a shorter postoperative stay. Further studies are required in high-risk (logistic EuroSCORE > 10) patients to define the role of MIAVR. PMID:26926521

  9. Aortic dissection

    MedlinePlus

    Aortic aneurysm - dissecting; Chest pain - aortic dissection; Thoracic aortic aneurysm - dissection ... also cause abnormal widening or ballooning of the aorta ( aneurysm ). The exact cause is unknown, but more common ...

  10. Aortic Aneurysm

    MedlinePlus

    ... chest and abdomen. There are two types of aortic aneurysm: Thoracic aortic aneurysms (TAA) - these occur in the part of the aorta running through the chest Abdominal aortic aneurysms (AAA) - these occur in the part of the ...

  11. Interleukin-10 appearance following thoraco-abdominal and abdominal aortic aneurysm repair is associated with the duration of visceral ischaemia.

    PubMed

    Oldenburg, H S; Burress Welborn, M; Pruitt, J H; Boelens, P G; Seeger, J M; Martin, T D; Wesdorp, R I; Rauwerda, J A; van Leeuwen, P A; Moldawer, L L

    2000-08-01

    to evaluate the plasma IL-10 levels during elective operative repair of thoraco-abdominal and abdominal aortic aneurysm repair. To study whether IL-10 plasma levels are associated with the duration of cross-clamping (ischaemia) and clinical outcome. fifteen consecutive patients undergoing surgery for TAAA and 10 consecutive patients undergoing surgical repair of AAA were included. plasma concentrations of IL-10 were measured by ELISA technique. Clinical outcome of the TAAA patients was prospectively analysed. during aortic clamping IL-10 was produced in both populations. The plasma IL-10 peak (934+/-172 pg/ml) of the TAAA group was seen at 4 h after declamping and remained detectable after 48 h. The plasma IL-10 peak (212+/-32 pg/ml) of the AAA group was seen 30 min after declamping and fell to undetectable levels by 24 h. These data show that the peak IL-10 plasma levels in TAAA repair are significantly (p<0.05) higher compared to the peak IL-10 plasma levels as seen during AAA repair. A positive correlation was seen between cross-clamping and peak plasma IL-10 and organ dysfunction. IL-10 plasma concentrations appear higher, later and are longer detectable in patients undergoing TAAA. Correlations were seen with duration of cross-clamping and MSOD. Copyright 2000 Harcourt Publishers Ltd.

  12. One stage surgical treatment of aortic valve disease and aortic coarctation with aortic bypass grafting through the diaphragm and aortic valve replacement.

    PubMed

    Yu, Zipu; Wu, Shengjun; Li, Chengchen; Zou, Yu; Ma, Liang

    2015-11-10

    To validate ascending aorta-lower abdominal aorta bypass grafting treatment for patients with descending aortic coarctation and an aortic valve disease. The three patients in whom a descending atypical aortic coarctation was associated with an aortic valve disease were treated with one stage surgical treatment with aortic bypass grafting through the diaphragm and aortic valve replacement in our heart center. Operative technique consisted of performing ascending aorta-lower abdominal aorta bypass grafting through diaphragm muscle and implementing aortic valve replacement. The mean time for extracorporeal circulation and occluding clamp of aorta was recorded. Blood pressure data for pre- and post-operation was measured in the limbs. Computer-enhanced transvenous angiograms of pre- and post-operation were applied for detection of aortic stenosis. The other adverse events were noticed in outpatient service during a follow-up period. The mean extracorporeal circulation time was 54 ± 11 min. The mean time for occluding clamp of aorta was 34 ± 6 min. An arterial pressure gradient was totally corrected after surgical treatment. Post-operation computer-enhanced transvenous angiograms showed the grafts to be open with a fluent flow. The patients had no gastrointestinal tract complications. No adverse event was noticed during a follow-up period in outpatient service. Treatment of ascending aorta-lower abdominal aorta bypass is advisable for patients with descending aortic coarctation and an aortic valve disease.

  13. Bilateral Leg Ischemia due to Descending Aortic Dissection: Combined Treatment with Femoro-femoral Cross-over Bypass and Unilateral Aorto-iliac stenting

    SciTech Connect

    Frahm, Christian; Widmer, Matthias K.; Do, Dai-Do

    2002-10-15

    We report a case of aorto-iliac occlusion due to descending aortic dissection treated initially with femoro-femoral cross-over bypass and secondarily with unilateral aorto-iliac stenting because of progression of the dissection. A 75-year-old man presented with acute ischemia of the right leg. CT revealed occlusion of the right iliac artery due to descending aortic dissection with a clotted false lumen. Three days after femoro-femoral cross-over bypass,ischemia of both legs developed and angiography demonstrated occlusion of the infrarenal aorta and left common iliac artery. Two overlapping stents were deployed in these vessel segments. Completion angiography confirmed successful recanalization with adequate distal flow and good patency of the cross-over bypass. Peripheral pulses were restored and the patient's symptoms were alleviated. Combined treatment with cross-over bypass and endovascular recanalization may be considered as a viable alternative to open aortic surgery in selected cases of complicated aorto-iliac dissection with bilateral leg ischemia.

  14. Clamping characteristics study on different types of clamping unit

    SciTech Connect

    Jiao, Zhiwei; Liu, Haichao; Xie, Pengcheng; Yang, Weimin

    2015-05-22

    Plastic products are becoming more and more widely used in aerospace, IT, digital electronics and many other fields. With the development of technology, the requirement of product precision is getting higher and higher. However, type and working performance of clamping unit play a decisive role in product precision. Clamping characteristics of different types of clamping unit are discussed in this article, which use finite element numerical analysis method through the software ABAQUS to study the clamping uniformity, and detect the clamping force repeatability precision. The result shows that compared with toggled three-platen clamping unit, clamping characteristics of internal circulation two-platen clamping unit are better, for instance, its mold cavity deformation and force that bars and mold parting surface suffered are more uniform, and its clamping uniformity and repeatability precision is also better.

  15. Reduction of gaseous microembolism during aortic valve replacement using a dynamic bubble trap.

    PubMed

    Schönburg, M; Ziegelhoeffer, T; Kraus, B; Mühling, A; Heidt, M; Taborski, U; Gerriets, T; Roth, M; Hein, S; Urbanek, S; Klövekorn, W P

    2006-06-01

    Serious postoperative psycho-neurological dysfunction is at least partially attributed to the occurrence of gaseous microbubbles in the arterial line of extracorporeal circulation (ECC). Therefore, we investigated in a prospective randomized double blind study whether the usage of dynamic bubble trap (DBT) will reduce microbubble load of patients undergoing aortic valve replacement. Patients (n = 41) were divided into group I (GI, n = 22) with DBT introduced into the arterial line of ECC and group II (GII, n = 19) with placebo-DBT instead. Doppler ultrasonography was used for detection of microbubbles before and after DBT, and for detection of high intensity transient signals (HITS) within the middle cerebral artery. The recording time during ECC was divided into period 1 (P1, until aortic clamp removal) and period 2 (P2, clamp removal until the end of ECC). A significant reduction of microbubble load was found in GI only (p < 0.0001 for ECC; p < 0.0001 for P1; p < 0.0025 for P2). A significant difference in number of HITS between the groups was observed in P1 only (p < 0.002 left middle cerebral artery, p < 0.005 right middle cerebral artery), since in P2 the trapped air in left chamber can go to the supraaortal vessels without passing ECC. In conclusion the use of DBT cannot substitute careful venting after aortic declamping. Nevertheless, reduction of HITS in the cross-clamped period of ECC justifies the use of DBT in patients undergoing open chamber surgery.

  16. Clamp for detonating fuze

    NASA Technical Reports Server (NTRS)

    Holderman, E. J.

    1968-01-01

    Quick acting clamp provides physical support for a closely confined detonating fuse in an application requiring removal and replacement at frequent intervals during test. It can be designed with a base of any required strength and configuration to permit the insertion of an object.

  17. Re-visiting the trans insertion model for complexin clamping

    PubMed Central

    Krishnakumar, Shyam S; Li, Feng; Coleman, Jeff; Schauder, Curtis M; Kümmel, Daniel; Pincet, Frederic; Rothman, James E; Reinisch, Karin M

    2015-01-01

    We have previously proposed that complexin cross-links multiple pre-fusion SNARE complexes via a trans interaction to function as a clamp on SNARE-mediated neurotransmitter release. A recent NMR study was unable to detect the trans clamping interaction of complexin and therefore questioned the previous interpretation of the fluorescence resonance energy transfer and isothermal titration calorimetry data on which the trans clamping model was originally based. Here we present new biochemical data that underscore the validity of our previous interpretation and the continued relevancy of the trans insertion model for complexin clamping. DOI: http://dx.doi.org/10.7554/eLife.04463.001 PMID:25831964

  18. Immediate or early cord clamping vs delayed clamping.

    PubMed

    Hutchon, D J R

    2012-11-01

    Over the past 40 years, there have been a number of review articles attempting to rationalise cord clamping practice. Early cord clamping was originally thought to be important in active management of the third stage of labour, but this was never evidence based. Without an evidence base to justify it, early cord clamping in clinical practice has remained very variable. There is good evidence that early cord clamping leads to hypovolaemia, anaemia and low iron stores in the neonate. We review all the evidence and discuss possible reasons why some obstetricians and midwives persevere with early clamping. We explain how a variable definition, defective education, deferred responsibility between obstetrician and paediatrician, variable guidelines and a lack of appreciation for the potential harm of the intervention, have all contributed. This study describes how the need for early cord clamping can be avoided in practically all clinical complications of birth.

  19. Newborn aortic arch reconstruction with descending aortic cannulation improves postoperative renal function.

    PubMed

    Hammel, James M; Deptula, Joseph J; Karamlou, Tara; Wedemeyer, Elesa; Abdullah, Ibrahim; Duncan, Kim F

    2013-11-01

    A clinically driven transition in perfusion technique occurred at Children's Hospital and Medical Center, Omaha, Nebraska, from primarily selective cerebral perfusion bracketed by brief periods of deep hypothermic circulatory arrest to a technique of dual arterial perfusion including innominate artery and descending aortic cannulation (DAC), with continuous mildly hypothermic (>30 °C) full-flow cardiopulmonary bypass to the entire body. This study retrospectively compared outcomes in a recent cohort of neonates undergoing aortic arch reconstruction with the two techniques. The clinical records of 142 consecutive neonates undergoing operations involving aortic arch reconstruction at a single institution between April 2004 and September 2012 were reviewed. Renal function changes were graded according to the pediatric RIFLE score (based on risk, injury, failure, loss, and end-stage kidney disease). Sixteen patients, 8 supported with selective cerebral perfusion bracketed by brief periods of deep hypothermic circulatory arrest and 8 with DAC, required immediate postoperative extracorporeal membrane oxygenation and were excluded from renal function analysis. Multivariable regression models evaluated predictors of pediatric RIFLE score. Patients with DAC had shorter median bypass support (113 versus 172 minutes; p < 0.001) and myocardial ischemic time (43 versus 81 minutes; p < 0.001). Patients with DAC had less median fluid gain at 24 hours (37 versus 69 mL/kg; p < 0.001), and lower incidence of acute kidney injury (5% versus 31%; p < 0.001). Fewer patients with DAC (31% versus 58%; p = 0.001) required open chest. Use of selective cerebral perfusion bracketed by brief periods of deep hypothermic circulatory arrest, single-ventricular physiology, and aortic cross-clamp time were found to be multivariable predictors of serious kidney dysfunction. Multisite arterial perfusion, including DAC, and maintenance of continuous mildly hypothermic full-flow cardiopulmonary bypass

  20. Cantilever clamp fitting

    NASA Technical Reports Server (NTRS)

    Melton, Patrick B. (Inventor)

    1989-01-01

    A device is disclosed for sealing and clamping a cylindrical element which is to be attached to an object such as a wall, a pressurized vessel or another cylindrical element. The device includes a gland having an inner cylindrical wall, which is threaded at one end and is attached at a bendable end to a deformable portion, which in turn is attached to one end of a conical cantilever structure. The other end of the cantilever structure connects at a bendable area to one end of an outer cylindrical wall. The opposite end of cylindrical wall terminates in a thickened portion, the radially outer surface of which is adapted to accommodate a tool for rotating the gland. The terminal end of cylindrical wall also includes an abutment surface, which is adapted to engage a seal, which in turn engages a surface of a receiver. The receiver further includes a threaded portion for engagement with the threaded portion of gland whereby a tightening rotation of gland relative to receiver will cause relative movement between cylindrical walls and of gland. This movement causes a rotation of the conical structure and thus a bending action at bending area and at the bending end of the upper end of inner cylindrical wall. These rotational and bending actions result in a forcing of the deformable portion radially inwardly so as to contact and deform a pipe. This forcible contact creates a seal between gland and pipe, and simultaneously clamps the pipe in position.

  1. Radi pressurewire rupture and embolization to the right common carotid artery after crossing a bjork-shiley mechanical aortic valve.

    PubMed

    Marmagkiolis, Konstantinos; Cilingiroglu, Mehmet

    2013-10-01

    Direct measurement of the left ventricular pressure in patients with mechanical prosthetic aortic valve is an important technical challenge. In the past, transseptal puncture or direct left ventricular accesses were the only available methods. The use of a pressure wire through mechanical aortic prosthesis has been described to be feasible and safe. We report the first case report of pressure guidewire entrapment through a single tilting disk valve (Bjork-Shiley), which resulted in hemodynamic collapse, rupture, and embolization of the pressure wire tip to the right common carotid artery and its successful snaring.

  2. Long-term evaluation of direct repair of traumatic isthmic aortic transection.

    PubMed

    Fernandez, G; Fontan, F; Deville, C; Madonna, F; Thibaud, D

    1989-01-01

    Direct repair of traumatic aortic isthmic transection eliminates the late complications of prosthetic graft repair. This study evaluates the long-term fate of direct aortic repair to which little attention has been paid. Among 32 patients operated upon from 1965 to 1987, 27 (84%) underwent direct repair. The tear was circumferential in 15 patients and partial in 12. Multiple traumatic lesions were present in 26 patients, including intracranial injury in 19. Partial cardiopulmonary bypass was used in 15 patients and simple aortic cross-clamping in 12. No paraplegia was observed. There were 4 deaths from associated lesions among the 14 patients operated upon for acute traumatic isthmic transection and no deaths in the others. Among the 23 survivors, 4 were lost to follow-up; the other 19 patients have excellent clinical results. Intravenous digital aortic angiography performed in 14 patients at a mean delay of 5 years 3 months showed excellent aortic reconstruction in all cases. Technically more demanding and faster than a graft interposition, direct repair is recommended as the procedure of choice in the surgical treatment of traumatic isthmic transection, particularly in young patients, the group most at risk from this lesion.

  3. Posterior enlargement of the small annulus during aortic valve replacement versus implantation of a small prosthesis.

    PubMed

    Pugliese, P; Bernabei, M; Santi, C; Pasqué, A; Eufrate, S

    1984-07-01

    Twenty-two patients with a small aortic annulus were identified among 196 consecutive patients undergoing aortic valve replacement (AVR). The 11 patients in Group 1 underwent posterior enlargement aortic annuloplasty, and the 11 in Group 2 received a small aortic prosthesis (less than or equal to 21 mm). The two groups were unselected. Core hypothermia, cardioplegia, and local cooling were employed for all operations. Isolated AVR was performed in 3 patients in each group. In Group 1, the mean increase in diameter of the annulus was 4.82 mm, which resulted in a mean area increase of 169.91 mm2 (51.7%). Mean aortic cross-clamp times were 140.4 minutes and 93.5 minutes in Groups 1 and 2, respectively. There were 2 operative deaths in Group 1, and 1 operative and 1 late death in Group 2. Mean follow-up was 26.5 months for Group 1 and 43.4 months for Group 2. No thomboembolic or bleeding episodes have been recorded. Considerations and conclusions are offered from the study of this small series of patients.

  4. Neonatal aortic arch hemodynamics and perfusion during cardiopulmonary bypass.

    PubMed

    Pekkan, Kerem; Dur, Onur; Sundareswaran, Kartik; Kanter, Kirk; Fogel, Mark; Yoganathan, Ajit; Undar, Akif

    2008-12-01

    The objective of this study is to quantify the detailed three-dimensional (3D) pulsatile hemodynamics, mechanical loading, and perfusion characteristics of a patient-specific neonatal aortic arch during cardiopulmonary bypass (CPB). The 3D cardiac magnetic resonance imaging (MRI) reconstruction of a pediatric patient with a normal aortic arch is modified based on clinical literature to represent the neonatal morphology and flow conditions. The anatomical dimensions are verified from several literature sources. The CPB is created virtually in the computer by clamping the ascending aorta and inserting the computer-aided design model of the 10 Fr tapered generic cannula. Pulsatile (130 bpm) 3D blood flow velocities and pressures are computed using the commercial computational fluid dynamics (CFD) software. Second order accurate CFD settings are validated against particle image velocimetry experiments in an earlier study with a complex cardiovascular unsteady benchmark. CFD results in this manuscript are further compared with the in vivo physiological CPB pressure waveforms and demonstrated excellent agreement. Cannula inlet flow waveforms are measured from in vivo PC-MRI and 3 kg piglet neonatal animal model physiological experiments, distributed equally between the head-neck vessels and the descending aorta. Neonatal 3D aortic hemodynamics is also compared with that of the pediatric and fetal aortic stages. Detailed 3D flow fields, blood damage, wall shear stress (WSS), pressure drop, perfusion, and hemodynamic parameters describing the pulsatile energetics are calculated for both the physiological neonatal aorta and for the CPB aorta assembly. The primary flow structure is the high-speed canulla jet flow (approximately 3.0 m/s at peak flow), which eventually stagnates at the anterior aortic arch wall and low velocity flow in the cross-clamp pouch. These structures contributed to the reduced flow pulsatility (85%), increased WSS (50%), power loss (28%), and blood

  5. Inner Voltage Clamping

    PubMed Central

    Feldberg, Stephen W.; Delgado, Alicia B.

    1978-01-01

    Ketterer, et al. (1971) have suggested that a combination of electrostatic and chemical interactions may cause hydrophobic ions absorbed within a bilayer lipid membrane to reside in two potential wells, each close to a membrane surface. The resulting two planes of charges would define three regions of membrane dielectric: two identical outer regions each between a plane of absorbed charges and the plane of closest approach of ions in the aqueous phase; and the inner region between the two planes of adsorbed charges. The theory describing charge translocation across the inner region is based on a simple three-capacitor model. A significant theoretical conclusion is that the difference between the voltage across the inner region, Vi, and the voltage across the entire membrane, Vm, is directly proportional to the amount of charge that has flowed in a voltage clamp experiment. We demonstrate that we can construct an “inner voltage clamp” that can maintain, with positive feedback, a constant inner voltage, Vi. The manifestation of proper feedback is that the clamp current (after a voltage step) will exhibit pure (i.e., single time-constant) exponential decay, because the voltage dependent rate constants governing translocation will be independent of time. The “pureness” of the exponential is maximized when the standard deviation of the least-square fit of the appropriate exponential equation to the experimental data is minimized. The concomitant feedback is directly related to the capacitances of the inner and outer membrane regions, Ci and Co. Experimental results with tetraphenylborate ion adsorbed in bacterial phosphatidylethanolamine/n-decane bilayers indicate Ci ∼ 5 · 10-7F/cm2 and Co ≈ 5 · 10-5F/cm2. PMID:620078

  6. Robot-assisted aortic valve replacement using a novel sutureless bovine pericardial prosthesis: proof of concept as an alternative to percutaneous implantation.

    PubMed

    Suri, Rakesh M; Burkhart, Harold M; Schaff, Hartzell V

    2010-11-01

    : Percutaneous aortic valve implantation within native valve calcium has progressed to clinical use despite the absence of data proving equivalence to complete surgical excision and prosthetic valve replacement. A novel self-expanding sutureless bovine pericardial prosthesis (Sorin Perceval) derived from a proven stented valve has been successfully used in humans recently through an open transaortic approach. We sought to develop a minimally invasive technique for native aortic valve excision and sutureless prosthetic aortic valve replacement using robot assistance. : The da Vinci S-HD system was used to open and suspend the pericardium anterior to the phrenic nerve in cadavers. A transthoracic cross-clamp was placed across the midascending aorta, following which a transverse aortotomy was made. The native aortic valve cusps were excised, and annular calcium was removed with robotic instruments. After placement of three guide sutures, the Perceval self-expanding pericardial prosthesis mounted on a flexible delivery system was inserted through a working port and lowered into the aortic annulus. : Successful implantation of all valves was possible using a 3-cm right second intercostal space working port, along with two additional 1-cm instrument ports. A standard transverse aortotomy was sufficient for examination/debridement of the native aortic valve cusps, sizing of the annulus, and deployment of the nitinol-stented, bovine pericardial prosthesis. Delivery, seating, and stability of the device were easily confirmed above and below the aortic valve annulus using the robotic camera. : Complete excision of diseased native aortic valve cusps with robot assistance facilitates accurate and reproducible aortic valve replacement using a novel self-expanding sutureless version of a proven bovine pericardial prosthesis. This approach is comparable to the current surgical gold standard and is ready for clinical use as an alternative to percutaneous aortic valve implantation.

  7. Anesthesia Management in Aortic Dissection in Patients Undergoing Kidney Transplant.

    PubMed

    Ucar, Muharrem; Erdil, Feray; Sanlı, Mukadder; Aydogan, Mustafa Said; Durmus, Mahmut

    2016-04-01

    Kidney transplant is a last resort to increase the life expectancy and quality of life in patients with renal failure. Aortic dissection is a disease that requires emergency intervention; it is characterized by sudden life-threatening back or abdominal pain. In the case described, constant chest pain that increased with respiration was present on examination of a 28-year-old man (85 kg, 173 cm) who presented at our emergency department complaining of severe back pain. He had undergone a kidney transplant in 2004 from his mother (live donor). He was diagnosed with acute Type II aortic dissection and was scheduled for emergent surgery. Because there were no surgical or anesthetic complications, the patient with 79 and 89 minutes aortic cross-clamping and cardiopulmonary bypass durations was sent, intubated, to intensive care unit. When nephrotoxic agents are avoided and blood flow is stabilized, cardiovascular surgery with cardio-pulmonary bypass may be performed seamlessly in patients who have undergone a kidney transplant.

  8. Single access for minimally invasive aortic valve replacement.

    PubMed

    Minale, C; Reifschneider, H J; Schmitz, E; Uckmann, F P

    1997-07-01

    The method of replacing the aortic valve via a minithoracotomy has been reported in the recent literature. Although this strategy has clear advantages, further refinements of the process make the procedure even less invasive. Aortic valve replacement was performed in 27 patients via a right parasternal minithoracotomy without rib resection. Cardiopulmonary bypass was connected through the same access site. Standard surgical technique and equipment were employed. There were no intraoperative complications. All patients survived and could be discharged home within 1 week, except 1. Cardiopulmonary bypass time, aortic cross-clamp time, and total operating time averaged 114 +/- 26, 76 +/- 19, and 190 +/- 40 minutes, respectively. Three patients could be extubated in the operative theater, the others in the intensive care unit at an average of 10 +/- 7 hours postoperatively. Chest drainage lost averaged 430 +/- 380 mL. The advantages of this method include further reduction of surgical trauma, early mobilization, and rehabilitation of the patient. Surgical technical improvements include avoidance of groin cannulation, simpler equipment, safe venting of the left ventricle, and preservation of chest wall integrity.

  9. Saddle Clamp With Captive Components

    NASA Technical Reports Server (NTRS)

    Belrose, Charles R.

    1993-01-01

    Saddle clamp modified to prevent parts from falling off when installed or removed. Allows easy access for tightening or loosening bolts, and retains alignment with tube mounted in it when opened. All parts are held captive - bolts by retaining washers, floating nuts by pressing and swaging, and upper clamp band by tether. Upper and lower bolt flanges offset from each other to ensure access.

  10. Computational evaluation of aortic occlusion and the proposal of a novel, improved occluder: Constrained endo-aortic balloon occlusion.

    PubMed

    de Vaal, M H; Gee, M W; Stock, U A; Wall, W A

    2016-12-01

    Because aortic occlusion is arguably one of the most dangerous aortic manipulation maneuvers during cardiac surgery in terms of perioperative ischemic neurological injury, the purpose of this investigation is to assess the structural mechanical impact resulting from the use of existing and newly proposed occluders. Existing (clinically used) occluders considered include different cross-clamps (CCs) and endo-aortic balloon occlusion (EABO). A novel occluder is also introduced, namely, constrained EABO (CEABO), which consists of applying a constrainer externally around the aorta when performing EABO. Computational solid mechanics are employed to investigate each occluder according to a comprehensive list of functional requirements. The potential of a state of occlusion is also considered for the first time. Three different constrainer designs are evaluated for CEABO. Although the CCs were responsible for the highest strains, largest deformation, and most inefficient increase of the occlusion potential, it remains the most stable, simplest, and cheapest occluder. The different CC hinge geometries resulted in poorer performance of CC used for minimally invasive procedures than conventional ones. CEABO with a profiled constrainer successfully addresses the EABO shortcomings of safety, stability, and positioning accuracy, while maintaining its complexities of operation (disadvantage) and yielding additional functionalities (advantage). Moreover, CEABO is able to achieve the previously unattainable potential to provide a clinically determinable state of occlusion. CEABO offers an attractive alternative to the shortcomings of existing occluders, with its design rooted in achieving the highest patient safety. Copyright © 2016 John Wiley & Sons, Ltd.

  11. Abdominal aortic aneurysm repair in a patient with bilateral autotransplanted kidneys.

    PubMed

    Neelakandhan, K S; Muralidhar, R; Unnikrishnan, M; Ravimandalam, K

    1994-04-01

    The case is presented of a 38-year-old male who presented with a large 10 cm x 8 cm pulsatile swelling in his abdomen. Thirteen years before, internal iliac arteries had been used to treat long segment occlusions and diseased state of both renal arteries. At the same time both kidneys had been transplanted to the iliac fossae. Digital subtraction angiography revealed a huge abdominal aortic aneurysm. Both kidneys were fully functional. As the renal transplants had been done extraperitoneally an easy transperitoneal approach was now possible. The maximum diameter of the aneurysm was 12 cm. An inclusion graft repair was carried out using a 16-mm woven Dacron graft. In the light of the favourable circumstances it was decided not to take any special protective measures against renal ischemia apart from keeping the aortic cross-clamp time short. The patient could be discharged with patent and normally functioning kidneys 10 days after surgery.

  12. Aortic Valve Replacement With the Stentless Freedom SOLO Bioprosthesis: A Systematic Review.

    PubMed

    Wollersheim, Laurens W; Li, Wilson W; Bouma, Berto J; Repossini, Alberto; van der Meulen, Jan; de Mol, Bas A

    2015-10-01

    This systematic review examined the clinical and hemodynamic performance of the stentless Freedom SOLO (Sorin Group, Milan, Italy) aortic bioprosthesis. The occurrence of postoperative thrombocytopenia was also analyzed. The Freedom SOLO is safe to use in everyday practice, with short cross-clamp times, and postoperative pacemaker implantation is notably lower. Valvular gradients are low and remain stable during short-term follow-up. Thrombocytopenia is more severe than in other aortic prostheses; however, this is without clinical consequences. Within a few years, the 15-year follow-up of this bioprosthesis will be known, which will be key to evaluating its long-term durability. Copyright © 2015 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  13. Aortic sutureless bioprosthesis implantation following degeneration of a SOLO stentless valve.

    PubMed

    Vola, Marco; Gerbay, Antoine; Campisi, Salvatore; Thulane, Claire; Fuzellier, François

    2015-03-01

    A case is presented of the early degeneration of a 21 mm SOLO stentless valve concomitant with severe mitral regurgitation (MR). Transcatheter valve-in-valve implantation was considered in this high-risk case (logistic EuroSCORE 29.3%), but was dismissed because of the risk of coronary occlusion, an absence of visual landmarks, and the impossibility to treat the MR. Following the implantation of a 27 mm Medtronic Hancock II mitral bioprosthesis, the leaflets of the SOLO valve were removed, and a 19 mm 3f Enable sutureless bioprosthesis delivered into the remaining sewing belt of the stentless valve. The total cross-clamp time was 64 min. No aortic paravalvular leakage was detected at discharge and early follow up (four months); the mean and peak transvalvular aortic gradients were 13 and 23 mmHg, respectively, and the left ventricular ejection fraction 60%. A sutureless strategy simplified the management of this high-risk case.

  14. Timing of cord clamping revisited.

    PubMed

    Levy, Tali; Blickstein, Isaac

    2006-01-01

    Although cord cutting has been performed since the beginning of mankind, the timing and advantages of early versus delayed cord clamping are still controversial. Early cord clamping (within the first 30 s after birth) is usually justified for potential prevention of postpartum hemorrhage and for immediate treatment of the newborn, but at the same time, may increase Rh-sensitization. Delayed cord clamping is performed after a period of 30 s during which 'placental transfusion' of approximately 80 mL of blood occurs. This amount seems to protect the baby from childhood anemia without increasing hypervolemia-related risks. In preterm infants, delayed clamping appears to reduce the risk of intraventricular hemorrhage and the need for neonatal transfusion. Obtaining cord blood for future autologous transplantation of stem cells needs early clamping and seems to conflict with the infant's best interest. Although a tailored approach is required in the case of cord clamping, the balance of available data suggests that delayed cord clamping should be the method of choice.

  15. Aortic reservoir characteristics and brain structure in people with type 2 diabetes mellitus; a cross sectional study.

    PubMed

    Climie, Rachel E D; Srikanth, Velandai; Beare, Richard; Keith, Laura J; Fell, James; Davies, Justin E; Sharman, James E

    2014-10-23

    Central hemodynamics help to maintain appropriate cerebral and other end-organ perfusion, and may be altered with ageing and type 2 diabetes mellitus (T2DM). We aimed to determine the associations between central hemodynamics and brain structure at rest and during exercise in people with and without T2DM. In a sample of people with T2DM and healthy controls, resting and exercise measures of aortic reservoir characteristics (including excess pressure integral [P(excess)]) and other central hemodynamics (including augmentation index [AIx] and aortic pulse wave velocity [aPWV]) were recorded. Brain volumes (including gray matter volume [GMV] and white matter lesions [WML]) were derived from magnetic resonance imaging (MRI) scans. Multivariable linear regression was used to study the associations of hemodynamic variables with brain structure in the two groups adjusting for age, sex, daytime systolic BP (SBP) and heart rate. There were 37 T2DM (63 ± 9 years; 47% male) and 37 healthy individuals (52 ± 8 years; 51% male). In T2DM, resting aPWV was inversely associated with GMV (standardized β = -0.47, p = 0.036). In healthy participants, resting P(excess) was inversely associated with GMV (β = -0.23, p = 0.043) and AIx was associated with WML volume (β = 0.52, p = 0.021). There were no associations between exercise hemodynamics and brain volumes in either group. Brain atrophy is associated with resting aortic stiffness in T2DM, and resting P(excess) in healthy individuals. Central vascular mechanisms underlying structural brain changes may differ between healthy individuals and T2DM.

  16. Internal V-Band Clamp

    DOEpatents

    Vaughn, Mark R.; Hafenrichter, Everett S.; Chapa, Agapito C.; Harris, Steven M.; Martinez, Marcus J.; Baty, Roy S.

    2006-02-28

    A system for clamping two tubular members together in an end-to-end relationship uses a split ring with a V-shaped outer rim that can engage a clamping surface on each member. The split ring has a relaxed closed state where the ends of the ring are adjacent and the outside diameter of the split ring is less than the minimum inside diameter of the members at their ends. The members are clamped when the split ring is spread into an elastically stretched position where the ring rim is pressed tightly against the interior surfaces of the members. Mechanisms are provided for removing the spreader so the split ring will return to the relaxed state, releasing the clamped members.

  17. Management of umbilical cord clamping.

    PubMed

    Webbon, Lucy

    2013-02-01

    The Royal College of Midwives (RCM) has updated its third stage of labour guidelines (RCM 2012) to be clearly supportive of a delay in umbilical cord clamping, although specific guidance on timing is yet to be announced. It is therefore imperative that both midwives and student midwives understand and are able to integrate delaying into their practice, as well as communicating to women the benefits; only in this way can we give women fully informed choices on this aspect of care. The main benefit of delayed cord clamping is the protection it can provide in reducing childhood anaemia, which is a major issue, especially in poorer countries. A review of the evidence found no risks linked to delayed clamping, and no evidence that it cannot be used in combination with the administration of uterotonic drugs. Delayed cord clamping can be especially beneficial for pre term and compromised babies.

  18. Beneficial effects of modern perfusion concepts in aortic valve and aortic root surgery.

    PubMed

    Kutschka, I; Skorpil, J; El Essawi, A; Hajek, T; Harringer, W

    2009-01-01

    Minimized perfusion circuits (MPC) were found to reduce side effects of standard extracorporeal circulation (ECC). We evaluated the safety and efficacy of the ROCsafe MPC for aortic valve and aortic root surgery. One hundred and seventy patients were randomized for surgery using either MPC [n = 85, 30 female/55 male, mean age: 69.8 +/- 11.8 years; aortic valve replacement (AVR): n = 40; AVR + coronary artery bypass graft (CABG): n = 31; David operation: n = 3; aortic root replacement (ARR): n = 11] or ECC [n = 85, 29 female/56 male, mean age: 67.7 +/- 9.5 years; AVR: n = 39; AVR+CABG: n = 35, David operation: n = 2; ARR: n = 9]. Neurological status, length of ICU stay, C-reactive protein (CRP), blood count, transfusion requirements and bleeding volume were analyzed. The MPC system provided ultrasound-controlled de-airing. A small roller pump and a flexible reservoir were used for left ventricular venting. As a control, we used a standard ECC with cardiotomy suction and hard-shell reservoir. Cross-clamp time (MPC: 76.5 +/- 29.5; ECC: 79.0 +/- 34.0 min) and bypass time (MPC: 103.0 +/- 37.9; ECC: 106.9 +/- 44.9 min) were comparable between groups. Transfusion requirements (red blood cells: MPC: 1.5 +/- 1.5 vs. ECC: 2.2 +/- 2.1 units [p = 0.05], frozen plasma: MPC: 1.2 +/- 1.8 vs. ECC: 1.9 +/- 2.4 units [p = 0.03]), postoperative bleeding (MPC: 521 +/- 283 vs. ECC: 615 +/- 326 ml/24 h, p = 0.09) were lower using MPC. ICU stay was shorter with MPC (1.6 +/- 1.6 days) compared to ECC (2.4 +/- 2.8 days, p = 0.001). One stroke occurred in each group. The ROCsafe MPC provides safe circulatory support for a wide range of aortic valve surgeries. Transfusion requirements, postoperative bleeding and length of ICU stay were markedly reduced compared to standard extracorporeal perfusion.

  19. Robot assisted Aortic and Non-aortic Vascular Operations.

    PubMed

    Štádler, P; Dvořáček, L; Vitásek, P; Matouš, P

    2016-07-01

    The aim of this study was to evaluate the clinical experience with 310 robot assisted vascular procedures. The da Vinci system has been used by a variety of disciplines for laparoscopic procedures but the use of robots in vascular surgery is still relatively uncommon. From November 2005 to May 2014, 310 robot assisted vascular operations were performed. Two hundred and twenty four patients were prospectively evaluated for occlusive disease, 61 patients for abdominal aortic aneurysm, four for a common iliac artery aneurysm, four for a splenic artery aneurysm, one for a internal mammary artery aneurysm, and after the unsuccessful endovascular treatment five for hybrid procedures, two patients for median arcuate ligament release and nine for endoleak II treatment post EVAR. Among these patients, 224 underwent robotic occlusive disease treatment (Group I), 65 robotic aorto-iliac aneurysm surgery (Group II) and 21 other robotic procedures (Group III). A total of 298 cases (96.1%) were successfully completed robotically. In 10 patients (3.2%) conversion was necessary. The 30 day mortality was 0.3%, and two (0.6%) late prosthetic infections were seen. Targeted Group I and Group II patients were compared. Robotic ilio-femoral bypass, aorto-femoral bypass, or aorto-iliac thrombo-endarterectomy with prosthetic patch (Group I) required an operative time of 194 (range, 127-315) minutes and robotic aorto-iliac aneurysm surgery (Group II), 253 (range, 185-360) minutes. The mean aortic cross clamping time was 37 minutes in Group I and 93 minutes in Group II. The mean blood loss was more significant in Group II (1,210 mL) than in Group I (320 mL). From a practical point of view, the greatest advantage of the robot assisted procedure has been the speed and relative simplicity of construction of the vascular anastomosis. This experience with robot assisted laparoscopic surgery has demonstrated the feasibility of this technique in different areas of vascular surgery. Copyright

  20. Early results of minimally invasive aortic valve replacement. Experience with the first 34 cases.

    PubMed

    Minale, C; Reifschneider, H J; Schmitz, E; Uckmann, F P

    1997-05-01

    The method of replacing the aortic valve via a minithoracotomy has been reported in the recent literature. This strategy has clear advantages. However, further refinements of the process make the procedure even less invasive. Aortic valve replacement was performed in 34 patients whose age ranged from 49 to 82 years, averaging 69 +/- 8 years. As access route, a right parasternal minithoracotomy about eight cm long and without rib resection was used. Cardiopulmonary bypass was connected through the same access. The standard surgical technique and equipment were employed. There were neither intraoperative complications nor hospital death. All patients, except two could be discharged home within one week. Cardiopulmonary bypass time, aortic cross-clamp time, and total operation time averaged 110 +/- 25, 73 +/- 19, and 183 +/- 38 minutes, respectively. Three patients could be extubated in the operating theater, and the others on the intensive care units at an average of 9 +/- 7 hours postoperatively. One patient had to be re-entered immediately after extubation because of a bleeding from the aortic cannulation site. A second patient, who was initially operated because of a florid aortitis, had a limited periprosthetic leak two months postoperatively which was repaired thereafter. The advantages of the present method include further reduction of surgical trauma, preservation of chest wall integrity, early mobilization, recovery and rehabilitation of the patient. Improvements in the surgical technique include avoidance of groin cannulation, simpler equipment, and an easy access through a mid-sternotomy in case of reoperation.

  1. [Operative results of distal aortic arch aneurysms--approaching methods, bypass techniques and complications].

    PubMed

    Ueda, T; Hayashi, I; Kurosaka, Y; Izeki, H; Onoguchi, K; Taguchi, S; Kawada, K

    1990-06-01

    Ten patients underwent repair of aneurysms of the distal aortic arch from 1985 to 1989. There were 8 men and 2 women: aged 58 to 77 (average age 67 years). Seven patients had sacciform aneurysms which were closed by graft patch aortoplasty, and three patients had fusiform aneurysms which were corrected by inserting tube grafts. Seven aneurysms operated since 1988 were approached through median sternotomy continued with left anterior thoracotomy, so called door open method. This approach presented good view of the diseased aorta, and effective for preventing recurrent and phrenic nerve palsy. We used temporary bypass for 4 patients, cardiopulmonary bypass for 4 patients (separate carotid artery perfusion for 2 patients) and centrifugal pump for 2 patients during aortic cross clamping. One patient died intraoperatively from intractable bleeding and two patients died postoperatively from brain damage due to embolic episodes during the operations. These patients showed the severely irregular intima in the aortic arch and were complicated with rupture of the aneurysm or dissections arising from the aneurysms. It should be noticed that careless manipulation of the aortic arch and the brachiocephalic vessels cause cerebral complications in such cases.

  2. Evolving strategies for treatment of acute aortic dissection type A.

    PubMed

    Kallenbach, Klaus; Oelze, Timm; Salcher, Rolf; Hagl, Christian; Karck, Matthias; Leyh, Rainer G; Haverich, Axel

    2004-09-14

    To assess the outcome of 3 different surgical approaches for treatment of acute aortic dissection type A (AADA). Between October 1990 and October 2003, we operated on 295 patients (pts) for AADA. Follow-up was complete for 257 pts (87%). Supracommissural replacement (SCR) of the ascending aorta was applied to 145 pts, 64 pts received a composite replacement (comp), and 48 pts were treated with the aorta valve-sparing (AVS) reimplantation technique. Pts in SCR were older compared with AVS and comp (P=0.002), gender (overall 65% male, P=0.143) and presence of Marfan syndrome (overall 5%, P=0.109) were comparable. Cannulation of the aorta was performed more often in AVS (58%) than in comp (19%) or SCR (22%; P<0.001). Mean operation time, extracorporeal circulation time, and aortic cross-clamp time differ significantly between groups (P<0.001, respectively). Stay in the intensive care unit (P=0.12) and time of hospitalization (P=0.32) were comparable. Overall perioperative mortality was 24% and did not show significant differences between groups (AVS 10.4% versus comp 28% versus SCR 26%; P=0.053). Incidence of neurological complications was similar between groups (P=0.95). Mean time of follow-up was shorter for AVS (19+/-20 months) compared with comp (48+/-48 months) and SCR (46+/-45 months). Survival at 5 years was comparable with 89% for AVS, 85% for comp, and 80% for SCR (P=0.61). Two patients from AVS (4.1%) required reoperation for failure of the reconstructed valve. Pts in comp required less aortic reoperations than pts in SCR (comp 6.3% versus SCR 22%; P=0.005). In acute aortic dissection type A, the reimplantation technique leads to results comparable to established techniques. Complete removal of diseased tissue, low incidence of reoperation, and lack of anticoagulation may favor this approach in selected patients.

  3. New device for saphenous vein-to-aorta proximal anastomosis without side-clamping

    PubMed Central

    Tappainer, Ernesto

    2007-01-01

    Background Side clamping to perform saphenous vein-to-aorta proximal anastomosis is a well known cause of cerebral embolization during coronary bypass surgery. Automatic and manual devices have been introduced to avoid aortic clamping and facilitate proximal anastomosis but the manual ones only allow the traditional hand-sewing running suture. Nevertheless, they are not easy to use and very expensive to buy. Methods We developed a simple object that helps to perform a manual proximal anastomosis without the need to clamp the side of the aorta. This device is a steel bar which blocks the aortic hole and simultaneously it provides a slit to receive the needle. Through the slit comes out a thin, sharp, straight, but also well directed and predictable jet of blood which could be easily controlled during the suture. Results The function of the object is quite different from other devices. Nothing is deployed in the aorta. The object is only placed on the aorta with the small appendage slipped into the hole. The main advantage of the device is that while manipulation of the aorta is avoided no foreign bodies are incorporated in the suture and – most importantly – the aortic intima is not touched at all. The main drawback of the device is the blood jet coming from the slit so that the blood pressure has to be lowered by vasodilators during the anastomosis. Moreover, the suture has to change direction and the needle has to enter the aortic wall first to slip out through the slit. Conclusion The object was named "Slit Device" and is not a routine instrument. It would be only an alternative to other anastomotic devices with the same surgical indications. In the case of ascending aortic disease and saphenous vein grafting, the Slit Device avoids aortic clamping thereby preventing atheroembolism and also avoiding the need for hypothermic circulatory arrest in patients with unclampable aorta. PMID:17480222

  4. Do we need sutureless or self-anchoring aortic valve prostheses?

    PubMed

    Shrestha, Malakh

    2015-03-01

    Surgical aortic valve replacement (AVR) is the 'gold standard' for the treatment of aortic valve stenosis. Due to the increasing age of the patient population (reflecting the demographic changes), the use of biological valves has increased over the past years. At the same time, a large proportion of these patients require concomitant surgical procedures in addition to AVR. Although trans-apical or trans-femoral aortic valve implantations (TAVI) have been introduced for high risk patients, they are limited to patients with isolated aortic valve pathology. Therefore, strategies for avoiding long ischemia times, as well as long periods of extra-corporeal circulation (ECC) resulting in reduced peri-operative risks should be welcomed among the surgical community. Modern 'sutureless valves' with reduced cross-clamp and cardio-pulmonary bypass times as a result of the absence of sutures, combined with excellent hemodynamics in the short and mid-term, may be an ideal solution for geriatric patients. Additionally, 'self-anchoring' valves will increase the armament of surgeons in treating 'technically difficult' group of patients needing AVR who have small calcified aortic roots and those coming back after aortic root replacement with homografts. These valves should also expand the application of minimally access AVR. Therefore, the question of whether we need 'self-anchoring valves' is not only redundant, but the time may have come for these type of valves to be considered as the 'valve of choice' for higher risk geriatric patients who may be 'high risk' for conventional valves but not ineligible for TAVIs.

  5. International Expert Consensus on Sutureless and Rapid Deployment Valves in Aortic Valve Replacement Using Minimally Invasive Approaches

    PubMed Central

    Glauber, Mattia; Moten, Simon C.; Quaini, Eugenio; Solinas, Marco; Folliguet, Thierry A.; Meuris, Bart; Miceli, Antonio; Oberwalder, Peter J.; Rambaldini, Manfredo; Teoh, Kevin H. T.; Bhatnagar, Gopal; Borger, Michael A.; Bouchard, Denis; Bouchot, Olivier; Clark, Stephen C.; Dapunt, Otto E.; Ferrarini, Matteo; Fischlein, Theodor J. M.; Laufer, Guenther; Mignosa, Carmelo; Millner, Russell; Noirhomme, Philippe; Pfeiffer, Steffen; Ruyra-Baliarda, Xavier; Shrestha, Malakh Lal; Suri, Rakesh M.; Troise, Giovanni; Gersak, Borut

    2016-01-01

    Objective To define the benefit of sutureless and rapid deployment valves in current minimally invasive approaches in isolated aortic valve replacement. Methods A panel of 28 international experts with expertise in both minimally invasive aortic valve replacement and rapid deployment valves was constituted. After thorough literature review, the experts rated evidence-based recommendations in a modified Delphi approach. Results No guideline could be retrieved. Thirty-three clinical trials and 9 systematic reviews could be identified for detailed text analysis to obtain a total of 24 recommendations. After rating by the experts 12, final recommendations were identified: preoperative computed tomographic scan as well as intraoperative transesophageal echocardiography are highly recommended. Suitable annular sizes are 19 to 27 mm. There is a contraindication for bicuspid valves only for type 0 and for annular abscess or destruction due to infective endocarditis. The use of sutureless and rapid deployment valves reduces extracorporeal circulation and aortic cross-clamp time and leads to less early complications as prolonged ventilation, blood transfusion, atrial fibrillation, pleural effusions, paravalvular leakages and aortic regurgitation, and renal replacement therapy, respectively. These clinical outcomes result in reduced intensive care unit and hospital stay and reduced costs. The use of sutureless and rapid deployment valves will lead to a higher adoption rate of minimally invasive approaches in aortic valve replacement. Respect should be taken to a necessary short learning curve for both sutureless and minimally invasive programs. Conclusions Sutureless and rapid deployment aortic valve replacement together with minimally invasive approaches offers an attractive option in aortic valve placement for patients requiring biological valve replacement. PMID:27540996

  6. Split-tapered joint clamping device

    DOEpatents

    Olsen, Max J.; Schwartz, Jr., John F.

    1988-01-01

    This invention relates to a clamping device for removably attaching a tool element to a bracket element wherein a bracket element is disposed in a groove in the tool and a clamping member is disposed in said groove and in engagement with a clamping face of the bracket and a wall of the groove and with the clamping member having pivot means engaging the bracket and about which the clamping member rotates.

  7. Micromachined patch-clamp apparatus

    SciTech Connect

    Okandan, Murat

    2012-12-04

    A micromachined patch-clamp apparatus is disclosed for holding one or more cells and providing electrical, chemical, or mechanical stimulation to the cells during analysis with the patch-clamp technique for studying ion channels in cell membranes. The apparatus formed on a silicon substrate utilizes a lower chamber formed from silicon nitride using surface micromachining and an upper chamber formed from a molded polymer material. An opening in a common wall between the chambers is used to trap and hold a cell for analysis using the patch-clamp technique with sensing electrodes on each side of the cell. Some embodiments of the present invention utilize one or more electrostatic actuators formed on the substrate to provide mechanical stimulation to the cell being analyzed, or to provide information about mechanical movement of the cell in response to electrical or chemical stimulation.

  8. Limit analysis of pipe clamps

    SciTech Connect

    Flanders, H.E. Jr.

    1990-01-01

    The Service Level D (faulted) load capacity of a conventional three-bolt pipe-clamp based upon the limit analysis method is presented. The load distribution, plastic hinge locations, and collapse load are developed for the lower bound limit load method. The results of the limit analysis are compared with the manufacturer's rated loads. 3 refs.

  9. The Effect of Perioperative Ischemia and Reperfusion on Multiorgan Dysfunction following Abdominal Aortic Aneurysm Repair

    PubMed Central

    Katseni, Konstantina; Kotsis, Thomas; Dafnios, Nikolaos; Arapoglou, Vassilis; Kaparos, Georgios; Logothetis, Emmanuel; Karvouni, Eleni; Katsenis, Konstantinos

    2015-01-01

    Abdominal aortic aneurysms (AAAs) are relatively common and are potentially life-threatening medical problems. The aim of this review is to provide an overview of the effect of I/R injury on multiorgan failure following AAA repair. The PubMed, CINAHL, EMBASE, Medline, Cochrane Review, and Scopus databases were comprehensively searched for articles concerning the pathophysiology of I/R and its systemic effects. Cross-referencing was performed using the bibliographies from the articles obtained. Articles retrieved were restricted to those published in English. One of the most prominent characteristics of AAA open repair is the double physiological phenomenon of ischemia-reperfusion (I/R) that happens either at the time of clamping or following the aortic clamp removal. Ischemia-reperfusion injury causes significant pathophysiological disturbances to distant organs, increasing the possibility for postoperative multiorgan failure. Although tissue injury is mediated by diverse mechanisms, microvascular dysfunction seems to be the final outcome of I/R. PMID:26798637

  10. [Aortic dissection].

    PubMed

    Ogino, Hitoshi

    2011-07-01

    Acute aortic dissection suddenly occurrs and results in a variety of catastrophic sequelae including cardiac tamponade, rupture, and organ malperfusion. In acute stage (< 2 weeks), according to the classifications on the region of aortic dissection, the condition of the false channel and the onset, appropriate medical, surgical, or endovascular treatments including endovascular aneurysm repair followed by the rapid and accurate diagnosis of aortic dissection using computed tomography and ultrasound should be performed without delay. In the chronic stage (> 2 weeks), the behavior of the chronic dissection or residual distal dissection after the initial treatment should be followed-up carefully with best medical treatment at the regular intervals. If necessary, appropriate surgical and endovascular treatment should be carried out in the proper timing before rupture.

  11. [Aortic aneurysm].

    PubMed

    Villar, Fernando; Pedro-Botet, Juan; Vila, Ramón; Lahoz, Carlos

    2013-01-01

    Aortic aneurysm is one important cause of death in our country. The prevalence of abdominal aortic aneurism (AAA) is around 5% for men older than 50 years of age. Some factors are associated with increased risk for AAA: age, hypertension, hypercholesterolemia, cardiovascular disease and, in particular, smoking. The medical management of patients with an AAA includes cardiovascular risk treatment, particularly smoking cessation. Most of major societies guidelines recommend ultrasonography screening for AAA in men aged 65 to 75 years who have ever smoked because it leads to decreased AAA-specific mortality. Copyright © 2013 Elsevier España, S.L. y SEA. All rights reserved.

  12. Pig specific vascular anatomy allows acute infrarenal aortic occlusion without hind limb ischemia and stepwise occlusion without clinical signs.

    PubMed

    Haacke, N; Unger, J K; Haidenhein, C; Russ, M; Hiebl, B; Niehues, S M

    2011-01-01

    EGAs for a partial collateral support of an infrarenal aortic occlusion the pig's EGA is a naturally sufficient collateral system capable to cover immediately for an acute infrarenal aortic occlusion. Further collateral enlargement even provides a permanent, sufficient hind limb perfusion in pigs. As the sufficient collateral system probably reduce pressure and shear rates in the infrarenal aortic segment after cross clamping, pigs might have a higher predisposition to produce early thrombosis related graft occlusions tan humans.

  13. Aortic valve replacement and concomitant right coronary artery bypass grafting performed via a right minithoracotomy approach.

    PubMed

    Mihos, Christos G; Santana, Orlando; Pineda, Andres M; La Pietra, Angelo; Lamelas, Joseph

    2014-01-01

    We present our experience of concomitant right coronary artery bypass grafting (CABG) and aortic valve replacement performed via a right minithoracotomy in patients with coronary lesions not amenable to percutaneous intervention. A total of 17 patients underwent concomitant aortic valve replacement and right CABG between April 2008 and July 2013. A 5- to 6-cm minithoracotomy incision was made over the right second or third intercostal space, and the costochondral cartilage was transected. A saphenous vein bypass to the right coronary artery was then performed, initiating the anastomosis from the toe of the graft. Subsequently, the aortic valve was replaced using standard techniques. There were 6 men and 11 women. The median European System for Cardiac Operative Risk Evaluation II score mortality risk was 5% [interquartile range (IQR), 2%-8%]. The mean (SD) age was 77 (10) years, the left ventricular ejection fraction was 59% (8%), and the New York Heart Association functional class was 2.4 (0.8). One patient had a history of CABG. The mean (SD) cardiopulmonary bypass time was 168 (57) minutes, and the aortic cross-clamp time was 133 (36) minutes. Three patients underwent concomitant mitral valve surgery (replacement, 2; repair, 1). The median intensive care unit and hospital lengths of stay were 47 hours (IQR, 24-90) and 9 days (IQR, 5-13), respectively. There was one reoperation for bleeding, and there was one postoperative stroke. All patients were alive at a mean (SD) follow-up of 2 (1.1) years. Aortic valve replacement with concomitant CABG performed via a right minithoracotomy approach is feasible.

  14. Minimally invasive aortic valve replacement without sternotomy. Experience with the first 50 cases.

    PubMed

    Minale, C; Reifschneider, H J; Schmitz, E; Uckmann, F P

    1998-10-01

    The method of replacing the aortic valve via a mini-thoracotomy has been reported in the recent literature. Although this strategy has clear advantages, further refinements of the process make the procedure even less invasive. Aortic valve replacement was performed in 50 patients whose age ranged between 49 and 82 years, averaging 68+/-8.3 years. As access route, a right parasternal mini-thoracotomy of about 8 cm, without rib resection was used. Cardiopulmonary bypass was connected through the same access. Standard surgical techniques and equipment were employed. In all patients a mechanical prosthesis was implanted. There were neither intraoperative complications nor hospital death. All patients could be discharged home at an average of 10+/-3 days postoperatively. Cardiopulmonary bypass time, aortic cross-clamp time, total operation time averaged 118+/-32, 70+/-21, 180+/-45 min, respectively. Four patients could be extubated in the operative theater, the others on the intensive care units at an average of 12+/-6 h, postoperatively. One patient with a very thin aortic wall sustained a severe bleeding from the aortic cannulation site during an hypertensive crisis, just after extubation. He had to be re-entered immediately via a median sternotomy. A second patient, who was initially operated on because of a floride aortitis, had a limited periprosthetic leak 2 months postoperatively. The leak was repaired via a median sternotomy. Drainage lost and blood substitution averaged 751+/-400 and 274+/-390, respectively. The advantages of the present method include further reduction of hospital trauma, preservation of chest wall integrity, early mobilization and rehabilitation of the patient. Surgical technical improvements include avoidance of groin cannulation, simpler equipment, and an easy access in case of reoperation.

  15. Is early cord clamping, delayed cord clamping or cord milking best?

    PubMed

    Vatansever, Binay; Demirel, Gamze; Ciler Eren, Elif; Erel, Ozcan; Neselioglu, Salim; Karavar, Hande Nur; Gundogdu, Semra; Ulfer, Gozde; Bahadir, Selcen; Tastekin, Ayhan

    2017-03-20

    To compare the antioxidant status of three cord clamping procedures (early clamping, delayed clamping and milking) by analyzing the thiol-disulfide balance. This randomized controlled study enrolled 189 term infants who were divided into three groups according to the cord clamping procedure: early clamping, delayed clamping and milking. Blood samples were collected from the umbilical arteries immediately after clamping, and the thiol/disulfide homeostasis was analyzed. The native and total thiol levels were significantly (p < .05) lower in the early cord clamping group compared with the other two groups. The disulfide/total thiol ratio was significantly (p = .026) lower in the delayed cord clamping and milking groups compared with the early clamping groups. Early cord clamping causes the production of more disulfide bonds and lower thiol levels, indicating that oxidation reactions are increased in the early cord clamping procedure compared with the delayed cord clamping and milking procedures. The oxidant capacity is greater with early cord clamping than with delayed clamping or cord milking. Delayed cord clamping or milking are beneficial in neonatal care, and we suggest that they be performed routinely in all deliveries.

  16. Delayed umbilical cord clamping in premature neonates.

    PubMed

    Kaempf, Joseph W; Tomlinson, Mark W; Kaempf, Andrew J; Wu, YingXing; Wang, Lian; Tipping, Nicole; Grunkemeier, Gary

    2012-08-01

    Delayed umbilical cord clamping is reported to increase neonatal blood volume. We estimated the clinical outcomes in premature neonates who had delayed umbilical cord clamping compared with a similar group who had early umbilical cord clamping. This was a before-after investigation comparing early umbilical cord clamping with delayed umbilical cord clamping (45 seconds) in two groups of singleton neonates, very low birth weight (VLBW) (401-1,500 g) and low birth weight (LBW) (greater than 1,500 g but less than 35 weeks gestation). Neonates were excluded from delayed umbilical cord clamping if they needed immediate major resuscitation. Primary outcomes were provision of delivery room resuscitation, hematocrit, red cell transfusions, and the principle Vermont Oxford Network outcomes. In VLBW neonates (77 delayed umbilical cord clamping, birth weight [mean±standard deviation] 1,099±266 g; 77 early umbilical cord clamping 1,058±289 g), delayed umbilical cord clamping was associated with less delivery room resuscitation, higher Apgar scores at 1 minute, and higher hematocrit. Delayed umbilical cord clamping was not associated with significant differences in the overall transfusion rate, peak bilirubin, any of the principle Vermont Oxford Network outcomes, or mortality. In LBW neonates (172 delayed umbilical cord clamping, birth weight [mean±standard deviation] 2,159±384 g; 172 early umbilical cord clamping 2,203±447 g), delayed umbilical cord clamping was associated with higher hematocrit and was not associated with a change in delivery room resuscitation or Apgar scores or with changes in the transfusion rate or peak bilirubin. Regression analysis showed increasing gestational age and birth weight and delayed umbilical cord clamping were the best predictors of higher hematocrit and less delivery room resuscitation. Delayed umbilical cord clamping can safely be performed in singleton premature neonates and is associated with a higher hematocrit, less delivery room

  17. False aneurysm of aorta secondary to partial occlusion clamp injury: diagnosis by nuclear flow study

    SciTech Connect

    Becker, R.M.; Wexler, J.; Frater, R.W.

    1981-09-01

    A 72-year-old woman presented 12 months postaortic valve replacement with a false aneurysm near the aortic cannulation site. The diagnosis was suspected from clinical findings and confirmed by a nuclear flow study. The patient refused surgery and died shortly afterward. At autopsy, a smooth-walled 1 cm defect adjacent to the cannulation site (presumably related to injury from a partial occlusion clamp) was found; this would have been easily reparable with surgery.

  18. Acute Aortic Syndromes and Thoracic Aortic Aneurysm

    PubMed Central

    Ramanath, Vijay S.; Oh, Jae K.; Sundt, Thoralf M.; Eagle, Kim A.

    2009-01-01

    Acute and chronic aortic diseases have been diagnosed and studied by physicians for centuries. Both the diagnosis and treatment of aortic diseases have been steadily improving over time, largely because of increased physician awareness and improvements in diagnostic modalities. This comprehensive review discusses the pathophysiology and risk factors, classification schemes, epidemiology, clinical presentations, diagnostic modalities, management options, and outcomes of various aortic conditions, including acute aortic dissection (and its variants intramural hematoma and penetrating aortic ulcers) and thoracic aortic aneurysms. Literature searches of the PubMed database were conducted using the following keywords: aortic dissection, intramural hematoma, aortic ulcer, and thoracic aortic aneurysm. Retrospective and prospective studies performed within the past 20 years were included in the review; however, most data are from the past 15 years. PMID:19411444

  19. The RFC clamp loader: structure and function.

    PubMed

    Yao, Nina Y; O'Donnell, Mike

    2012-01-01

    The eukaryotic RFC clamp loader couples the energy of ATP hydrolysis to open and close the circular PCNA sliding clamp onto primed sites for use by DNA polymerases and repair factors. Structural studies reveal clamp loaders to be heteropentamers. Each subunit contains a region of homology to AAA+ proteins that defines two domains. The AAA+ domains form a right-handed spiral upon binding ATP. This spiral arrangement generates a DNA binding site within the center of RFC. DNA enters the central chamber through a gap between the AAA+ domains of two subunits. Specificity for a primed template junction is achieved by a third domain that blocks DNA, forcing it to bend sharply. Thus only DNA with a flexible joint can bind the central chamber. DNA entry also requires a slot in the PCNA clamp, which is opened upon binding the AAA+ domains of the clamp loader. ATP hydrolysis enables clamp closing and ejection of RFC, completing the clamp loading reaction.

  20. Aortic Valve Regurgitation

    MedlinePlus

    ... valve. Also, a narrowing of the aortic valve (aortic stenosis) can be associated with leaking. High blood pressure (hypertension). High blood pressure may stretch the root of the aorta where the aortic valve sits. The valve flaps ( ...

  1. Thoracic aortic aneurysm

    MedlinePlus

    Aortic aneurysm - thoracic; Syphilitic aneurysm; Aneurysm - thoracic aortic ... The most common cause of a thoracic aortic aneurysm is hardening of ... high cholesterol, long-term high blood pressure, or who smoke. ...

  2. Determination of right ventricular volumes during aortic surgery.

    PubMed

    Van der Linden, P; Gilbart, E; Engelman, E; de Rood, M; Vincent, J L

    1989-06-01

    The aim of the present study was to evaluate right ventricular (RV) preload by measurements of right ventricular volumes during aortic clamping and unclamping. Nine patients (aged 67 +/- 9 years) undergoing infrarenal aortic aneurysmectomy were monitored with a pulmonary artery catheter equipped with a fast-response thermistor, allowing determination of RV volumes by the thermodilution technique. Anesthesia consisted of a continuous infusion of alfentanil and 50% N2O. Aortic clamping resulted in a significant decrease in cardiac index (CI) and a significant increase in systemic vascular resistance (SVR). There was no significant change in right ventricular ejection fraction (RVEF) (from 35% +/- 6% to 33% +/- 8%) in the presence of a significant decrease in stroke index (from 37.2 +/- 9.8 to 31.1 +/- 10.0 mL/beat/m2, P less than 0.05), indicating a significant decrease in RV end-diastolic volume (from 106 +/- 17 to 92 +/- 19 mL, P less than 0.01). There were no significant changes in cardiac filling pressures. Aortic unclamping was associated with a significant increase in CI and a significant decrease in SVR. There were no significant changes in cardiac filling pressures, RVEF, or RV volumes. Measurements of RV volumes indicated that aortic clamping resulted in a decrease in RV preload, which is usually not demonstrated by measurements of right atrial pressure alone.

  3. Aortic Stenosis.

    PubMed

    Bakaeen, Faisal G; Rosengart, Todd K; Carabello, Blase A

    2017-01-03

    This issue provides a clinical overview of aortic stenosis, focusing on screening, diagnosis, treatment, and practice improvement. The content of In the Clinic is drawn from the clinical information and education resources of the American College of Physicians (ACP), including MKSAP (Medical Knowledge and Self-Assessment Program). Annals of Internal Medicine editors develop In the Clinic in collaboration with the ACP's Medical Education and Publishing divisions and with the assistance of additional science writers and physician writers.

  4. Comparison of different surgical techniques in 112 consecutive patients with aortic root operations: when should the valve be spared?

    PubMed

    Blehm, Alexander; Schurr, Paulus; Sorokin, Vitaly A; Zianikal, Ioanna; Kamiya, Hiroyuki; Albert, Alexander; Lichtenberg, Artur

    2014-01-01

    The benefit of valve-sparing aortic root replacement compared to conventional aortic root replacement surgery remains unclear. Between February 2009 and November 2010, a total of 112 patients underwent aortic root surgery at the Department of Cardiovascular and Thoracic Surgery, Heinrich-Heine-University, Dusseldorf, Germany. The valve-sparing technique was used when leaflets were grossly normal. In cases where the valve could not be saved, a prosthetic or biological substitute was used for the aortic root, according to existing guidelines. The patients were allocated to three groups: (i) valve-sparing aortic root replacement group using the David technique (VSR-David; n = 47); (ii) valve-replacing aortic root surgery with a prosthetic conduit using the Bentall-Kuchucus technique (VRR-Prosthetic; n = 31); and (iii) valve-replacing aortic root surgery with a biological stentless valve with the full root technique (VRR-Bio; n = 34). Intraoperative data revealed that, in the VSR-David group, the cardiopulmonary bypass and cross-clamp times were significantly longer (207 +/- 68 min and 140 +/- 38 min respectively; both p = 0.001). The VRR-Prosthetic patients were at highest risk (mean EuroSCORE 15.9%) compared to the VSR-David and VRR-Bio groups (10.8% and 10.4%, respectively). Postoperative analysis showed that patients in the VRR-Bio group had the lowest number of perioperative heart failures (p = 0.004). The perioperative 30-day mortality was significantly higher in the VRR-Prosthetic group (22.6%; p = 0.004). Transaortic flow velocities were significantly lower in the VSR-David group, followed by the VRR-Bio group and VRR-Prosthetic group (1.66 +/- 0.54, 1.98 +/- 0.45, and 2.29 +/- 0.39 m/s, respectively; p = 0.012). The univariate and multivariate analyses of perioperative risk factors showed that only open distal anastomosis was strongly associated with negative results, but not the valve-sparing technique. Aortic valve-sparing root replacement must be considered

  5. Analysis of early and long-term outcomes of acute type A aortic dissection according to the new international aortic arch surgery study group recommendations.

    PubMed

    Colli, Andrea; Carrozzini, Massimiliano; Galuppo, Marco; Comisso, Marina; Toto, Francesca; Gregori, Dario; Gerosa, Gino

    2016-10-01

    To evaluate predictors of early and long-term outcomes of surgical repair of acute Type A aortic dissection. Retrospective single-centre study evaluating patients surgically treated between 1998 and 2013. Clinical follow-up was performed. Complications were classified according to the International Aortic Arch Surgery Study Group recommendations. Statistical analysis included univariate and multivariate analysis of preoperative and operative data. One hundred eighty-five patients were evaluated. The follow-up was complete for 180 patients (97 %). Mean age was 63 years, 82 % had a DeBakey type I aortic dissection, 18 % a type II. Eleven patients (6 %) died intraoperatively, 119 of the remaining (68 %) had postoperative complications. Thirty-day mortality was 21 % (38 patients). Average ICU and hospital stay were 6 and 14 days, respectively. During a mean follow-up time of 6 ± 4 years we observed 44 deaths (31 %). Twenty patients (14 %) needed late thoracic aorta reoperation. Results from the multivariate analysis are as follows. Thirty-day mortality was associated with abdominal pain at presentation (p < 0.01). The incidence of postoperative complications was related to older age at intervention (p < 0.01) and longer cross-clamp time (p < 0.01). Mortality at follow-up was significantly increased by older age at intervention (p < 0.01), with a logarithmic growth after 60 years, female sex (p < 0.01), preoperative limb ischemia (p = 0.02) and DHCA (p < 0.01). The surgical results of type A aortic dissection are affected by age at intervention with a logarithmic increase of late mortality in patients older than 60 years.

  6. Non-invasive spinal cord oxygenation monitoring: validating collateral network near-infrared spectroscopy for thoracoabdominal aortic aneurysm repair.

    PubMed

    von Aspern, Konstantin; Haunschild, Josephina; Hoyer, Alexandro; Luehr, Maximilian; Bakhtiary, Farhad; Misfeld, Martin; Mohr, Friedrich W; Etz, Christian D

    2016-10-01

    Near-infrared spectroscopy of the collateral network (cnNIRS) has recently been trialled to monitor real-time tissue oxygenation of the paraspinous vasculature as a surrogate for spinal cord tissue oxygenation. This large animal study was designed to investigate the correlation between cnNIRS and spinal cord oxygenation by comparing it to laser Doppler flowmetry (LDF), a proven method for direct oxygenation and flow assessment. Measurements were performed in seven animals. Four paravertebral cnNIRS optodes were positioned bilaterally at thoracic and lumbar levels to assess tissue oxygenation of the paraspinous vasculature. Paravertebral muscle and spinal cord oxygenation and microcirculatory flow were measured directly using LDF probes. LDF and cnNIRS were compared during consecutive repeated periods of descending aortic cross-clamping for 8 min and recovery by clamp release. Following aortic cross-clamping, lumbar cnNIRS signals instantaneously responded with a decrease to 85 ± 4% within 30 s, and to a minimum of 69 ± 6% after 8 min, returning to baseline values after clamp release within 40 s. Direct lumbar muscle and spinal cord oxygenation assessed by LDF responded analogously to cnNIRS (muscle and spinal cord oxygenation after cross-clamping 11.3 ± 6 and 37.6 ± 22% after 5 and 8 min, respectively). Comparison between lumbar cnNIRS and LDF muscle and spinal cord measurements showed a significant positive correlation (r = 0.51-0.52, P < 0.001). Thoracic cnNIRS signals remained relatively stable throughout the procedure. Lumbar paraspinous muscle oxygenation corresponded to direct spinal cord oxygenation (no significant difference, P = 0.296). These experiments confirm that the paraspinous vasculature in the presented large animal model is directly linked to spinal cord microcirculation and that the regional paraspinous muscle oxygenation status reflects spinal cord tissue oxygenation. As lumbar cnNIRS reproducibly depicts tissue oxygenation of the

  7. MicroRNA-19b is a potential biomarker of increased myocardial collagen cross-linking in patients with aortic stenosis and heart failure

    PubMed Central

    Beaumont, Javier; López, Begoña; Ravassa, Susana; Hermida, Nerea; José, Gorka San; Gallego, Idoia; Valencia, Félix; Gómez-Doblas, Juan José; de Teresa, Eduardo; Díez, Javier; González, Arantxa

    2017-01-01

    This study analyzed the potential associations of 7 myocardial fibrosis-related microRNAs with the quality of the collagen network (e.g., the degree of collagen fibril cross-linking or CCL) and the enzyme lysyl oxidase (LOX) responsible for CCL in 28 patients with severe aortic stenosis (AS) of whom 46% had a diagnosis of chronic heart failure (HF). MicroRNA expression was analyzed in myocardial and blood samples. From the studied microRNAs only miR-19b presented a direct correlation (p < 0.05) between serum and myocardium. Compared to controls both myocardial and serum miR-19b were reduced (p < 0.01) in AS patients. In addition, miR-19b was reduced in the myocardium (p < 0.01) and serum (p < 0.05) of patients with HF compared to patients without HF. Myocardial and serum miR-19b were inversely correlated (p < 0.05) with LOX, CCL and LV stiffness in AS patients. In in vitro studies miR-19b inhibition increased (p < 0.05) connective tissue growth factor protein and LOX protein expression in human fibroblasts. In conclusion, decreased miR-19b may be involved in myocardial LOX up-regulation and excessive CCL, and consequently increased LV stiffness in AS patients, namely in those with HF. Serum miR-19b can be a biomarker of these alterations of the myocardial collagen network in AS patients, particularly in patients with HF. PMID:28091585

  8. MicroRNA-19b is a potential biomarker of increased myocardial collagen cross-linking in patients with aortic stenosis and heart failure.

    PubMed

    Beaumont, Javier; López, Begoña; Ravassa, Susana; Hermida, Nerea; José, Gorka San; Gallego, Idoia; Valencia, Félix; Gómez-Doblas, Juan José; de Teresa, Eduardo; Díez, Javier; González, Arantxa

    2017-01-16

    This study analyzed the potential associations of 7 myocardial fibrosis-related microRNAs with the quality of the collagen network (e.g., the degree of collagen fibril cross-linking or CCL) and the enzyme lysyl oxidase (LOX) responsible for CCL in 28 patients with severe aortic stenosis (AS) of whom 46% had a diagnosis of chronic heart failure (HF). MicroRNA expression was analyzed in myocardial and blood samples. From the studied microRNAs only miR-19b presented a direct correlation (p < 0.05) between serum and myocardium. Compared to controls both myocardial and serum miR-19b were reduced (p < 0.01) in AS patients. In addition, miR-19b was reduced in the myocardium (p < 0.01) and serum (p < 0.05) of patients with HF compared to patients without HF. Myocardial and serum miR-19b were inversely correlated (p < 0.05) with LOX, CCL and LV stiffness in AS patients. In in vitro studies miR-19b inhibition increased (p < 0.05) connective tissue growth factor protein and LOX protein expression in human fibroblasts. In conclusion, decreased miR-19b may be involved in myocardial LOX up-regulation and excessive CCL, and consequently increased LV stiffness in AS patients, namely in those with HF. Serum miR-19b can be a biomarker of these alterations of the myocardial collagen network in AS patients, particularly in patients with HF.

  9. Aortic Valve Adaptation to Aortic Root Dilatation

    PubMed Central

    Kim, Dae-Hee; Handschumacher, Mark D.; Levine, Robert A.; Sun, Byung Joo; Jang, Jeong Yoon; Yang, Dong Hyun; Kang, Joon-Won; Song, Jong-Min; Kang, Duk-Hyun; Lim, Tae-Hwan; Song, Jae-Kwan

    2015-01-01

    Background The 3-dimensional relationship between aortic root and cusp is essential to understand the mechanism of aortic regurgitation (AR) because of aortic root dilatation (ARD). We sought to test the hypothesis that the stretched cusps in ARD enlarge to compensate for ARD. Methods and Results Computed tomography imaged 92 patients (57 with ARD, 29 with moderate to severe AR, 28 without significant AR) and 35 normal controls. Specialized 3-dimensional software measured individual cusp surface areas relative to maximal mid-sinus cross-sectional area and minimal 3-dimensional annular area, coaptation area fraction, and asymmetry of sinus volumes and intercommissural distances. Total open cusp surface area increased (P<0.001) from 7.6±1.4 cm2/m2 in normals to 12.9±2.2 cm2/m2 in AR-negative and 15.2±3.3 cm2/m2 in AR-positive patients. However, the ratio of closed cusp surface area to maximal mid-sinus area, reflecting cusp adaptation, decreased from normals to AR-negative to AR-positive patients (1.38±0.20, 1.15±0.15, 0.88±0.15; P<0.001), creating the lowest coaptation area fraction. Cusp distensibility (closed diastolic versus open area) decreased from 20% in controls and AR-negative patients to 5% in AR-positive patients (P<0.001). Multivariate determinants of AR and coaptation area fraction reflected both sinus size and cusp-to-annular adaptation. ARD was also progressively asymmetrical with root size, and individual cusp surface areas failed to match this asymmetry. Conclusions Aortic cusp enlargement occurs in ARD, but cusp adaptation and distensibility become limited in prominent, asymmetrical ARD, leading to AR. Optimal AR repair tailored to individual patient anatomy can benefit from appreciating valve adaptation and 3-dimensional relationships; understanding cusp adaptation mechanisms may ultimately provide therapeutic opportunities to improve such compensation. PMID:25051951

  10. High-speed pressure clamp.

    PubMed

    Besch, Stephen R; Suchyna, Thomas; Sachs, Frederick

    2002-10-01

    We built a high-speed, pneumatic pressure clamp to stimulate patch-clamped membranes mechanically. The key control element is a newly designed differential valve that uses a single, nickel-plated piezoelectric bending element to control both pressure and vacuum. To minimize response time, the valve body was designed with minimum dead volume. The result is improved response time and stability with a threefold decrease in actuation latency. Tight valve clearances minimize the steady-state air flow, permitting us to use small resonant-piston pumps to supply pressure and vacuum. To protect the valve from water contamination in the event of a broken pipette, an optical sensor detects water entering the valve and increases pressure rapidly to clear the system. The open-loop time constant for pressure is 2.5 ms for a 100-mmHg step, and the closed-loop settling time is 500-600 micros. Valve actuation latency is 120 micros. The system performance is illustrated for mechanically induced changes in patch capacitance.

  11. Comparison of echocardiography and angiography in determining the cause of severe aortic regurgitation.

    PubMed

    DePace, N L; Nestico, P F; Kotler, M N; Mintz, G S; Kimbiris, D; Goel, I P; Glazier-Laskey, E E; Ross, J

    1984-01-01

    To assess the accuracy of echocardiography in determining the cause of aortic regurgitation M mode and cross sectional echocardiography were compared with angiography in 43 patients with predominant aortic regurgitation. Each patient had all three investigations performed during the same admission to hospital. In each instance, the cause of aortic regurgitation was confirmed at surgery or necropsy. Seventeen patients had rheumatic aortic valve disease, 13 bacterial endocarditis with a perforated or partially destroyed cusp, five a bicuspid aortic valve (four with a history of endocarditis), and eight aortic regurgitation secondary to aortic root dilatation or aneurysm. Overall sensitivity of echocardiography and aortography was 84% in determining the cause of aortic regurgitation. Thus, rheumatic valve disease and endocarditis appear to be the most common causes of severe aortic regurgitation in this hospital based population. Furthermore, echocardiography is a sensitive non-invasive technique for determining the cause of aortic regurgitation and allows differentiation of valvular from root causes of aortic regurgitation.

  12. Comparison of echocardiography and angiography in determining the cause of severe aortic regurgitation.

    PubMed Central

    DePace, N L; Nestico, P F; Kotler, M N; Mintz, G S; Kimbiris, D; Goel, I P; Glazier-Laskey, E E; Ross, J

    1984-01-01

    To assess the accuracy of echocardiography in determining the cause of aortic regurgitation M mode and cross sectional echocardiography were compared with angiography in 43 patients with predominant aortic regurgitation. Each patient had all three investigations performed during the same admission to hospital. In each instance, the cause of aortic regurgitation was confirmed at surgery or necropsy. Seventeen patients had rheumatic aortic valve disease, 13 bacterial endocarditis with a perforated or partially destroyed cusp, five a bicuspid aortic valve (four with a history of endocarditis), and eight aortic regurgitation secondary to aortic root dilatation or aneurysm. Overall sensitivity of echocardiography and aortography was 84% in determining the cause of aortic regurgitation. Thus, rheumatic valve disease and endocarditis appear to be the most common causes of severe aortic regurgitation in this hospital based population. Furthermore, echocardiography is a sensitive non-invasive technique for determining the cause of aortic regurgitation and allows differentiation of valvular from root causes of aortic regurgitation. Images PMID:6689919

  13. Aortic Baroreceptors Display Higher Mechanosensitivity than Carotid Baroreceptors

    PubMed Central

    Lau, Eva On-Chai; Lo, Chun-Yin; Yao, Yifei; Mak, Arthur Fuk-Tat; Jiang, Liwen; Huang, Yu; Yao, Xiaoqiang

    2016-01-01

    Arterial baroreceptors are mechanical sensors that detect blood pressure changes. It has long been suggested that the two arterial baroreceptors, aortic and carotid baroreceptors, have different pressure sensitivities. However, there is no consensus as to which of the arterial baroreceptors are more sensitive to changes in blood pressure. In the present study, we employed independent methods to compare the pressure sensitivity of the two arterial baroreceptors. Firstly, pressure-activated action potential firing was measured by whole-cell current clamp with a high-speed pressure clamp system in primary cultured baroreceptor neurons. The results show that aortic depressor neurons possessed a higher percentage of mechano-sensitive neurons. Furthermore, aortic baroreceptor neurons show a lower pressure threshold than that of carotid baroreceptor neurons. Secondly, uniaxial stretching of baroreceptor neurons, that mimics the forces exerted on blood vessels, elicited a larger increase in intracellular Ca2+ rise in aortic baroreceptor neurons than in carotid baroreceptor neurons. Thirdly, the pressure-induced action potential firing in the aortic depressor nerve recorded in vivo was also higher. The present study therefore provides for a basic physiological understanding on the pressure sensitivity of the two baroreceptor neurons and suggests that aortic baroreceptors have a higher pressure sensitivity than carotid baroreceptors. PMID:27630578

  14. [A clamp for suturing of duodenal stump].

    PubMed

    Komarov, I A

    1991-03-01

    An original clamp was used in suturing a duodenal stump after gastric resection in 77 patients. The complex relief of the blades of the clamp holds the duodenum reliably during application of the sutures and ensures their air-tightness. The trauma inflicted to the duodenum in this case is minimal. During resection of the stomach in 37 patients the author used the clamp in closure of the lesser curvature. Incompetence of the duodenal stump was not encountered.

  15. Advanced motor driven clamped borehole seismic receiver

    DOEpatents

    Engler, Bruce P.; Sleefe, Gerard E.; Striker, Richard P.

    1993-01-01

    A borehole seismic tool including a borehole clamp which only moves perpendicular to the borehole. The clamp is driven by an electric motor, via a right angle drive. When used as a seismic receiver, the tool has a three part housing, two of which are hermetically sealed. Accelerometers or geophones are mounted in one hermetically sealed part, the electric meter in the other hermetically sealed part, and the clamp and right angle drive in the third part. Preferably the tool includes cable connectors at both ends. Optionally a shear plate can be added to the clamp to extend the range of the tool.

  16. Advanced motor driven clamped borehole seismic receiver

    DOEpatents

    Engler, B.P.; Sleefe, G.E.; Striker, R.P.

    1993-02-23

    A borehole seismic tool is described including a borehole clamp which only moves perpendicular to the borehole. The clamp is driven by an electric motor, via a right angle drive. When used as a seismic receiver, the tool has a three part housing, two of which are hermetically sealed. Accelerometers or geophones are mounted in one hermetically sealed part, the electric motor in the other hermetically sealed part, and the clamp and right angle drive in the third part. Preferably the tool includes cable connectors at both ends. Optionally a shear plate can be added to the clamp to extend the range of the tool.

  17. The "stable" ruptured abdominal aortic aneurysm gives a false sense of security.

    PubMed

    Weinstein, E S; Cooper, M; Hammond, S; Carlson, R; Guber, M; Maloy, J

    1999-08-01

    Operative mortality for ruptured abdominal aortic aneurysms (rAAA) has not changed over the past 4 decades. Previous studies have attempted to identify preoperative risk factors that impact upon survival. A retrospective review of 25 patients with rAAA treated during a 2-year period was performed. Patients were divided into groups based upon the presence (GpI), absence (GpIIa), or subsequent development of preoperative hypotension (GpIIb). Time intervals from initial presentation to arrival in the operating room (IP-OR), to cross clamp application (IP-XC), and from observed hypotension to cross clamp (HYPO-XC) were recorded. Average time intervals for IP-OR and IP-XC were significantly shorter for GpI compared with GpIIa and GpIIb. No difference in HYPO-XC was noted between GpI and GpIIb. Mortality was 33% for GpI, 25% for GpIIa, and 87.5% for GpIIb. Normal admission blood pressure led to a decreased sense of urgency, creating avoidable delays and missed opportunities for salvage.

  18. Clinical outcomes of valve-sparing root replacement in acute type A aortic dissection.

    PubMed

    Lee, Heemoon; Cho, Yang Hyun; Sung, Kiick; Kim, Wook Sung; Park, Kay-Hyun; Park, Pyo Won; Lee, Young Tak

    2015-01-01

    The early and late outcomes of valve-sparing root replacement (VSR) in type A aortic dissection (AAD) are unknown. The aim of this study was to review the outcomes of VSR in AAD. We also compared the outcomes of VSR with the Bentall operation, which served as a standard reference technique. We retrospectively reviewed 52 patients who underwent surgery for AAD and concomitant root replacement between 1998 and 2013 at Samsung Medical Center. Patients were divided into two groups: Bentall (n = 34) and VSR (n = 18). Two out of six surgeons performed VSR. The mean follow-up duration was 62.3 ± 46.5 months. Preoperative characteristics were similar between the two groups except age (Bentall, 48 ± 11 years; VSR, 37 ± 11 years, p = 0.011). The aortic cross-clamping time was longer in the VSR group (Bentall, 185.8 ± 63.8; VSR, 241.4 ± 44.3 min, p = 0.002). There was no early death in the VSR group, but there was one in the Bentall group (p = 1.000). Despite the higher reoperation rate for aortic valve in the VSR group (Three reoperations) than in the Bentall group (no reoperation), major valve-related events and overall mortality did not differ between the two groups(p = 0.876 and 0.119, respectively). In multivariable analysis, the root replacement technique was not a risk factor for major valve-related events. VSR seems to be equivalent to the Bentall procedure for AAD in terms of early and late outcomes. VSR can be considered as a viable option, particularly for young patients with favorable aortic valve leaflets undergoing surgery at an experienced center.

  19. Characterization of neonatal aortic cannula jet flow regimes for improved cardiopulmonary bypass.

    PubMed

    Menon, Prahlad G; Teslovich, Nikola; Chen, Chia-Yuan; Undar, Akif; Pekkan, Kerem

    2013-01-18

    During pediatric and neonatal cardiopulmonary bypass (CPB), tiny aortic outflow cannulae (2-3 mm inner diameter), with micro-scale blood-wetting features transport relatively large blood volumes (0.3 to 1.0 L/min) resulting in high blood flow velocities (2 to 5 m/s). These severe flow conditions are likely to complement platelet activation, release pro-inflammatory cytokines, and further result in vascular and blood damage. Hemodynamically efficient aortic outflow cannulae are required to provide high blood volume flow rates at low exit force. In addition, optimal aortic insertion strategies are necessary in order to alleviate hemolytic risk, post-surgical neurological complications and developmental defects, by improving cerebral perfusion in the young patient. The methodology and results presented in this study serve as a baseline for design of superior aortic outflow cannulae. In this study, direct numerical simulation (DNS) computational fluid dynamics (CFD) was employed to delineate baseline hemodynamic performance of jet wakes emanating from microCT scanned state-of-the-art pediatric cannula tips in a cuboidal test rig operating at physiologically relevant laminar and turbulent Reynolds numbers (Re: 650-2150 , steady inflow). Qualitative and quantitative validation of CFD simulated device-specific jet wakes was established using time-resolved flow visualization and particle image velocimetry (PIV). For the standard end-hole cannula tip design, blood damage indices were further numerically assessed in a subject-specific cross-clamped neonatal aorta model for different cannula insertion configurations. Based on these results, a novel diffuser type cannula tip is proposed for improved jet flow-control, decreased blood damage and exit force and increased permissible flow rates. This study also suggests that surgically relevant cannula orientation parameters such as outflow angle and insertion depth may be important for improved hemodynamic performance. The jet

  20. Aortic Dissection in Patients With Bicuspid Aortic Valve–Associated Aneurysms

    PubMed Central

    Wojnarski, Charles M.; Svensson, Lars G.; Roselli, Eric E.; Idrees, Jay J.; Lowry, Ashley M.; Ehrlinger, John; Pettersson, Gösta B.; Gillinov, A. Marc; Johnston, Douglas R.; Soltesz, Edward G.; Navia, Jose L.; Hammer, Donald F.; Griffin, Brian; Thamilarasan, Maran; Kalahasti, Vidyasagar; Sabik, Joseph F.; Blackstone, Eugene H.; Lytle, Bruce W.

    2016-01-01

    Background Data regarding the risk of aortic dissection in patients with bicuspid aortic valve and large ascending aortic diameter are limited, and appropriate timing of prophylactic ascending aortic replacement lacks consensus. Thus our objectives were to determine the risk of aortic dissection based on initial cross-sectional imaging data and clinical variables and to isolate predictors of aortic intervention in those initially prescribed serial surveillance imaging. Methods From January 1995 to January 2014, 1,181 patients with bicuspid aortic valve underwent cross-sectional computed tomography (CT) or magnetic resonance imaging (MRI) to ascertain sinus or tubular ascending aortic diameter greater than or equal to 4.7 cm. Random Forest classification was used to identify risk factors for aortic dissection, and among patients undergoing surveillance, time-related analysis was used to identify risk factors for aortic intervention. Results Prevalence of type A dissection that was detected by imaging or was found at operation or on follow-up was 5.3% (n = 63). Probability of type A dissection increased gradually at a sinus diameter of 5.0 cm—from 4.1% to 13% at 7.2 cm—and then increased steeply at an ascending aortic diameter of 5.3 cm—from 3.8% to 35% at 8.4 cm—corresponding to a cross-sectional area to height ratio of 10 cm2/m for sinuses of Valsalva and 13 cm2/m for the tubular ascending aorta. Cross-sectional area to height ratio was the best predictor of type A dissection (area under the curve [AUC] = 0.73). Conclusions Early prophylactic ascending aortic replacement in patients with bicuspid aortic valve should be considered at high-volume aortic centers to reduce the high risk of preventable type A dissection in those with aortas larger than approximately 5.0 cm or with a cross-sectional area to height ratio greater than approximately 10 cm2/m. PMID:26209494

  1. 21 CFR 870.4450 - Vascular clamp.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Vascular clamp. 870.4450 Section 870.4450 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Surgical Devices § 870.4450 Vascular clamp. (a) Identification. A vascular...

  2. Time to implement delayed cord clamping.

    PubMed

    McAdams, Ryan M

    2014-03-01

    Immediate umbilical cord clamping after delivery is routine in the United States despite little evidence to support this practice. Numerous trials in both term and preterm neonates have demonstrated the safety and benefit of delayed cord clamping. In premature neonates, delayed cord clamping has been shown to stabilize transitional circulation, lessening needs for inotropic medications and reducing blood transfusions, necrotizing enterocolitis, and intraventricular hemorrhage. In term neonates, delayed cord clamping has been associated with decreased iron-deficient anemia and increased iron stores with potential valuable effects that extend beyond the newborn period, including improvements in long-term neurodevelopment. The failure to more broadly implement delayed cord clamping in neonates ignores published benefits of increased placental blood transfusion at birth and may represent an unnecessary harm for vulnerable neonates.

  3. Midwives in India: a delayed cord clamping intervention using simulation.

    PubMed

    Faucher, M A; Riley, C; Prater, L; Reddy, M P

    2016-09-01

    Iron deficiency is a prevalent health problem in India affecting women and newborns. Delayed umbilical cord clamping at birth is a safe and effective means for increasing serum iron levels in newborns up to 6 months of age. The study aim was to increase the utilization of delayed cord clamping in a group of midwives working in Hyderabad, India. A single group pre- and post-test design was used to evaluate knowledge, beliefs and practice before and after a delayed cord clamping intervention including follow-up at 10 months after the original intervention. The intervention included lectures and simulation. Results show significant increases in knowledge and positive beliefs about the practice of delayed cord clamping. Simulation was effective for eliciting important feedback related to learning. Results represent a small group of midwives working with a non-profit foundation in Southern India. Language discordancy and cultural norms in this group of midwives may have influenced results. Knowledge, beliefs and practice related to delayed cord clamping were all significantly improved after the intervention. The Knowledge to Action framework using simulation is an effective cross-cultural method for implementing education about evidence-based practice. Midwives are invested in learning practices that promote public health. Changing institutional policy may have limitations without first considering normative practice. Using simulation combined with institutional health policy appears to result in significant uptake of practice change. Qualitative studies exploring the interconnections between cultural norms and decision making may be informative about promoting practice change particularly in this setting. Upscaling midwifery has been recommended to improve maternal and child health in India. © 2016 International Council of Nurses.

  4. Influence of municipality-level mean income on access to aortic valve surgery: a cross-sectional observational study under Japan's universal health-care coverage.

    PubMed

    Lee, Seitetsu L; Hashimoto, Hideki; Kohro, Takahide; Horiguchi, Hiromasa; Koide, Daisuke; Komuro, Issei; Fushimi, Kiyohide; Yamazaki, Tsutomu; Yasunaga, Hideo

    2014-01-01

    Universal health-care coverage has attracted the interest of policy makers as a way of achieving health equity. However, previous reports have shown that despite universal coverage, socioeconomic disparity persists in access to high-tech invasive care, such as cardiac treatment. In this study, we aimed to investigate the association between socioeconomic status and care of aortic stenosis in the context of Japan's health-care system, which is mainly publicly funded. We chose aortic stenosis in older people as a target because such patients are likely to be affected by socioeconomic disparity. Using a large Japanese claim-based inpatient database, we identified 12,893 isolated aortic stenosis patients aged over 65 years who were hospitalized between July 2010 and March 2012. Municipality socioeconomic status was represented by the mean household income of the patients' residential municipality, categorized into quartiles. The likelihood of undergoing aortic valve surgery and in-hospital mortality was regressed against socioeconomic status level with adjustments for hospital volume, regional number of cardiac surgeons per 1 million population, and patients' clinical status. We found no significant differences between the highest and lowest quartile groups in surgical indication (odds ratio, 0.84; 95% confidence interval, 0.69-1.03) or in-hospital mortality (1.00; 0.68-1.48). Hospital volume was significantly associated with lower postoperative mortality (odds ratio of the highest volume tertile to the lowest, 0.49; 0.34-0.71). Under Japan's current universal health-care coverage, municipality socioeconomic status did not appear to have a systematic relationship with either treatment decision for surgical intervention or postoperative survival following aortic valve surgery among older patients. Our results imply that universal health-care coverage with high publicly funded coverage offers equal access to high-tech cardiovascular care.

  5. Influence of Municipality-Level Mean Income on Access to Aortic Valve Surgery: A Cross-Sectional Observational Study under Japan's Universal Health-Care Coverage

    PubMed Central

    Lee, Seitetsu L.; Hashimoto, Hideki; Kohro, Takahide; Horiguchi, Hiromasa; Koide, Daisuke; Komuro, Issei; Fushimi, Kiyohide; Yamazaki, Tsutomu; Yasunaga, Hideo

    2014-01-01

    Background Universal health-care coverage has attracted the interest of policy makers as a way of achieving health equity. However, previous reports have shown that despite universal coverage, socioeconomic disparity persists in access to high-tech invasive care, such as cardiac treatment. In this study, we aimed to investigate the association between socioeconomic status and care of aortic stenosis in the context of Japan's health-care system, which is mainly publicly funded. Methods We chose aortic stenosis in older people as a target because such patients are likely to be affected by socioeconomic disparity. Using a large Japanese claim-based inpatient database, we identified 12,893 isolated aortic stenosis patients aged over 65 years who were hospitalized between July 2010 and March 2012. Municipality socioeconomic status was represented by the mean household income of the patients' residential municipality, categorized into quartiles. The likelihood of undergoing aortic valve surgery and in-hospital mortality was regressed against socioeconomic status level with adjustments for hospital volume, regional number of cardiac surgeons per 1 million population, and patients' clinical status. Results We found no significant differences between the highest and lowest quartile groups in surgical indication (odds ratio, 0.84; 95% confidence interval, 0.69–1.03) or in-hospital mortality (1.00; 0.68–1.48). Hospital volume was significantly associated with lower postoperative mortality (odds ratio of the highest volume tertile to the lowest, 0.49; 0.34–0.71). Conclusions Under Japan's current universal health-care coverage, municipality socioeconomic status did not appear to have a systematic relationship with either treatment decision for surgical intervention or postoperative survival following aortic valve surgery among older patients. Our results imply that universal health-care coverage with high publicly funded coverage offers equal access to high

  6. Combat ready clamp medic technique.

    PubMed

    Tovmassian, Robert V; Kragh, John F; Dubick, Michael A; Baer, David G; Blackbourne, Lorne H

    2012-01-01

    Junctional hemorrhage control device use on the battlefield might be lifesaving, but little experience is reported. The purpose of the present case report is to detail prehospital use of the Combat Ready Clamp (called the CRoC by its users, Combat Medical Systems, Fayetteville, NC; Instructions for Use, 2010) in casualty care in order to increase awareness of junctional hemorrhage control. The CRoC was used to control difficult inguinal bleeding on the battlefield for an Afghani man with a hindquarter traumatic amputation. The device promptly controlled exsanguination from a critical injury when placed during rotary-wing casualty evacuation. The flight medic applied the device in 90 seconds. The device performed well without complications to control bleeding. The CRoC, a new junctional hemorrhage control device, was used as indicated on the battlefield with mechanical and physiologic success and without device problems. By controlling difficult inguinal bleeding resulting from battlefield trauma, the device facilitated casualty stabilization and delivery to a surgical facility. The device facilitated the ability of a new flight medic to focus his expertise on a critically injured battlefield casualty with demonstrable success. 2012.

  7. Embolic capture with updated intra-aortic filter during coronary artery bypass grafting and transaortic transcatheter aortic valve implantation: first-in-human experience.

    PubMed

    Ye, Jian; Webb, John G

    2014-12-01

    We report our first-in-human clinical experience in the use of the new version of the EMBOL-X intra-aortic filter (Edwards Lifesciences Corporation, Irvine, Calif) to capture embolic material during transaortic transcatheter aortic valve implantation and cardiac surgery. Five patients were enrolled into the first-in-human clinical assessment of the new version of the EMBOL-X intra-aortic filter. Three patients underwent coronary artery bypass grafting, and 2 patients underwent transaortic transcatheter aortic valve implantation. During coronary artery bypass grafting, the filter was deployed before clamping of the aorta and removal of the aortic clamp. In contrast, the filter was deployed before aortic puncture for transaortic transcatheter aortic valve implantation and kept in the aorta throughout the entire procedure. The filter introducer sheath and filter were easily placed and removed without difficulty. There were no complications related to the use of the filter. Postoperative examination of the retrieved filters revealed the presence of multiple microemboli in the filters from all 5 cases. Histologic study revealed various kinds of tissue and thrombus. This first-in-human clinical experience has demonstrated the safety and feasibility of using the new version of the EMBOL-X intra-aortic filter during either cardiac surgery or transaortic transcatheter aortic valve implantation. We believe that the combination of the transaortic approach without aortic arch manipulation and the use of the EMBOL-X filter with a high capture rate is a promising strategy to reduce the incidence of embolic complications during transcatheter aortic valve implantation. Copyright © 2014 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

  8. Minimally invasive aortic valve replacement: 12-year single center experience

    PubMed Central

    Solinas, Marco; Farneti, Pier Andrea; Cerillo, Alfredo Giuseppe; Kallushi, Enkel; Santarelli, Filippo; Glauber, Mattia

    2015-01-01

    Background This study reports the single center experience on minimally invasive aortic valve replacement (MIAVR), performed through a right anterior minithoracotomy or ministernotomy (MS). Methods Eight hundred and fifty-three patients, who underwent MIAVR from 2002 to 2014, were retrospectively analyzed. Survival was evaluated using the Kaplan-Meier method. The Cox multivariable proportional hazards regression model was developed to identify independent predictors of follow-up mortality. Results Median age was 73.8, and 405 (47.5%) of patients were female. The overall 30-day mortality was 1.9%. Four hundred and forty-three (51.9%) and 368 (43.1%) patients received biological and sutureless prostheses, respectively. Median cardiopulmonary bypass time and aortic cross-clamping time were 108 and 75 minutes, respectively. Nineteen (2.2%) cases required conversion to full median sternotomy. Thirty-seven (4.3%) patients required re-exploration for bleeding. Perioperative stroke occurred in 15 (1.8%) patients, while transient ischemic attack occurred postoperative in 11 (1.3%). New onset atrial fibrillation was reported for 243 (28.5%) patients. After a median follow-up of 29.1 months (2,676.0 patient-years), survival rates at 1 and 5 years were 96%±1% and 80%±3%, respectively. Cox multivariable analysis showed that advanced age, history of cardiac arrhythmia, preoperative chronic renal failure, MS approach, prolonged mechanical ventilation and hospital stay as well as wound revision were associated with higher mortality. Conclusions MIAVR via both approaches is safe and feasible with excellent outcomes, and is associated with low conversion rate and low perioperative morbidity. Long term survival is at least comparable to that reported for conventional sternotomy AVR. PMID:25870812

  9. Stent valve implantation in conventional redo aortic valve surgery to prevent patient-prosthesis mismatch.

    PubMed

    Ferrari, Enrico; Franciosi, Giorgio; Clivio, Sara; Faletra, Francesco; Moccetti, Marco; Moccetti, Tiziano; Pedrazzini, Giovanni; Demertzis, Stefanos

    2017-03-01

    The goal was to show the technical details, feasibility and clinical results of balloon-expandable stent valve implantation in the aortic position during conventional redo open-heart surgery in selected obese patients with a small aortic prosthesis and severe patient-prosthesis mismatch. Two symptomatic overweight patients (body mass index of 31 and 38), each with a small aortic prosthesis (a 4-year-old, 21-mm Hancock II biological valve and a 29-year-old, 23-mm Duromedic mechanical valve), increased transvalvular gradients (59/31 and 74/44 mmHg) and a reduced indexed effective orifice area (0.50 and 0.43 cm 2 /m 2 ) underwent implantation of two 26-mm balloon-expandable Sapien 3 valves during standard on-pump redo valve surgery. Using full re-sternotomy, cardiopulmonary bypass and cardioplegic arrest, the two balloon-expandable stent valves were implanted under direct view using a standard aortotomy, after prosthesis removal and without annulus enlargement. Aortic cross-clamp times were 162 and 126 min; cardiopulmonary bypass times were 178 and 180 min; total surgical times were 360 and 318 min. At discharge, echocardiograms showed transvalvular peak and mean gradients of 13/9 and 23/13 mmHg and indexed effective orifice areas of 0.64 and 1.08 cm 2 /m 2 . The 3-month echocardiographic follow-up showed transvalvular peak and mean gradients of 18/9 and 19/11 mmHg and indexed effective orifice areas of 0.78 cm 2 /m 2 and 0.84 cm 2 /m 2 , with improved symptoms (New York Heart Association class 1). Implantation of a balloon-expandable stent valve during redo aortic valve surgery is feasible in selected cases and prevents patient-prosthesis mismatch in obese patients without need for aortic annulus enlargement. Moreover, in the case of stent valve degeneration, this approach permits additional valve-in-valve procedures with large stent valves and prevents re-redo surgery.

  10. Selective cerebro-myocardial perfusion in complex congenital aortic arch pathology: a novel technique.

    PubMed

    De Rita, Fabrizio; Lucchese, Gianluca; Barozzi, Luca; Menon, Tiziano; Faggian, Giuseppe; Mazzucco, Alessandro; Luciani, Giovanni Battista

    2011-11-01

    Simultaneous cerebro-myocardial perfusion has been described in neonatal and infant arch surgery, suggesting a reduction in cardiac morbidity. Here reported is a novel technique for selective cerebral perfusion combined with controlled and independent myocardial perfusion during surgery for complex or recurrent aortic arch lesions. From April 2008 to April 2011, 10 patients with arch pathology underwent surgery (two hypoplastic left heart syndrome [HLHS], four recurrent arch obstruction, two aortic arch hypoplasia + ventricular septal defect [VSD], one single ventricle + transposition of the great arteries + arch hypoplasia, one interrupted aortic arch type B + VSD). Median age was 63 days (6 days-36 years) and median weight 4.0 kg (1.6-52). Via midline sternotomy, an arterial cannula (6 or 8 Fr for infants) was directly inserted into the innominate artery or through a polytetrafluoroethylene (PTFE) graft (for neonates <2.0 kg). A cardioplegia delivery system was inserted into the aortic root. Under moderate hypothermia, ascending and descending aorta were cross-clamped, and "beating heart and brain" aortic arch repair was performed. Arch repair was composed of patch augmentation in five, end-to-side anastomosis in three, and replacement in two patients. Average cardiopulmonary bypass time was 163 ± 68 min (71-310). In two patients only (one HLHS, one complex single ventricle), a period of cardiac arrest was required to complete intracardiac repair. In such cases, antegrade blood cardioplegia was delivered directly via the same catheter used for selective myocardial perfusion. Average time of splanchnic ischemia during cerebro-myocardial perfusion was 39 ± 18 min (17-69). Weaning from cardiopulmonary bypass was achieved without inotropic support in three and with low dose in seven patients. One patient required veno-arterial extracorporeal membrane oxygenation. Four patients, body weight <3.0 kg, needed delayed sternal closure. No neurologic dysfunction was noted

  11. Aortic valve replacement in rheumatoid aortic incompetence.

    PubMed Central

    Devlin, A B; Goldstraw, P; Caves, P K

    1978-01-01

    Rheumatoid aortic valve disease is uncommon. and there are few reports of valve replacement in this condition. Aortic valve replacement and partial pericardiectomy was performed in a patient with acute rheumatoid aortitis and aortic incompetence. Previous reports suggest that any patient with rheumatoid arthritis who develops cardiac symptoms should be carefully assessed for surgically treatable involvement of the pericardium or heart valves. Images PMID:725829

  12. The monogenean which lost its clamps.

    PubMed

    Justine, Jean-Lou; Rahmouni, Chahrazed; Gey, Delphine; Schoelinck, Charlotte; Hoberg, Eric P

    2013-01-01

    Ectoparasites face a daily challenge: to remain attached to their hosts. Polyopisthocotylean monogeneans usually attach to the surface of fish gills using highly specialized structures, the sclerotized clamps. In the original description of the protomicrocotylid species Lethacotyle fijiensis, described 60 years ago, the clamps were considered to be absent but few specimens were available and this observation was later questioned. In addition, genera within the family Protomicrocotylidae have either clamps of the "gastrocotylid" or the "microcotylid" types; this puzzled systematists because these clamp types are characteristic of distinct, major groups. Discovery of another, new, species of the genus Lethacotyle, has allowed us to explore the nature of the attachment structures in protomicrocotylids. Lethacotyle vera n. sp. is described from the gills of the carangid Caranx papuensis off New Caledonia. It is distinguished from Lethacotyle fijiensis, the only other species of the genus, by the length of the male copulatory spines. Sequences of 28S rDNA were used to build a tree, in which Lethacotyle vera grouped with other protomicrocotylids. The identity of the host fish was confirmed with COI barcodes. We observed that protomicrocotylids have specialized structures associated with their attachment organ, such as lateral flaps and transverse striations, which are not known in other monogeneans. We thus hypothesized that the clamps in protomicrocotylids were sequentially lost during evolution, coinciding with the development of other attachment structures. To test the hypothesis, we calculated the surfaces of clamps and body in 120 species of gastrocotylinean monogeneans, based on published descriptions. The ratio of clamp surface: body surface was the lowest in protomicrocotylids. We conclude that clamps in protomicrocotylids are vestigial organs, and that occurrence of "gastrocotylid" and simpler "microcotylid" clamps within the same family are steps in an

  13. The Monogenean Which Lost Its Clamps

    PubMed Central

    Justine, Jean-Lou; Rahmouni, Chahrazed; Gey, Delphine; Schoelinck, Charlotte; Hoberg, Eric P.

    2013-01-01

    Ectoparasites face a daily challenge: to remain attached to their hosts. Polyopisthocotylean monogeneans usually attach to the surface of fish gills using highly specialized structures, the sclerotized clamps. In the original description of the protomicrocotylid species Lethacotyle fijiensis, described 60 years ago, the clamps were considered to be absent but few specimens were available and this observation was later questioned. In addition, genera within the family Protomicrocotylidae have either clamps of the “gastrocotylid” or the “microcotylid” types; this puzzled systematists because these clamp types are characteristic of distinct, major groups. Discovery of another, new, species of the genus Lethacotyle, has allowed us to explore the nature of the attachment structures in protomicrocotylids. Lethacotyle vera n. sp. is described from the gills of the carangid Caranx papuensis off New Caledonia. It is distinguished from Lethacotyle fijiensis, the only other species of the genus, by the length of the male copulatory spines. Sequences of 28S rDNA were used to build a tree, in which Lethacotyle vera grouped with other protomicrocotylids. The identity of the host fish was confirmed with COI barcodes. We observed that protomicrocotylids have specialized structures associated with their attachment organ, such as lateral flaps and transverse striations, which are not known in other monogeneans. We thus hypothesized that the clamps in protomicrocotylids were sequentially lost during evolution, coinciding with the development of other attachment structures. To test the hypothesis, we calculated the surfaces of clamps and body in 120 species of gastrocotylinean monogeneans, based on published descriptions. The ratio of clamp surface: body surface was the lowest in protomicrocotylids. We conclude that clamps in protomicrocotylids are vestigial organs, and that occurrence of “gastrocotylid” and simpler “microcotylid” clamps within the same family are

  14. Onset of asphyxial state in nonrespiring interval between cord clamping and ventilation increases hemodynamic lability of birth transition in preterm lambs.

    PubMed

    Smolich, Joseph J; Kenna, Kelly R; Cheung, Michael M

    2015-03-15

    Experimentally, a typical ∼2-min cord clamp-to-ventilation interval in preterm lambs is accompanied by increased hemodynamic lability of the birth transition. However, whether this lability is related to development of asphyxia after cord clamping, or can be avoided with a shorter clamp-to-ventilation interval, is unknown. To address these questions, anesthetized preterm fetal lambs (gestation 127 ± 2 days) were instrumented with ductus arteriosus and left pulmonary artery flow probes to obtain right ventricular (RV) output, brachiocephalic trunk and aortic isthmus flow probes to measure left ventricular (LV) output, and aortic trunk catheters for pressure measurement and blood gas analysis. With hemodynamics recorded continuously, fetuses were delivered onto the ewe's abdomen and the cord clamped for 1.5 min before ventilation (n = 8), with aortic sampling at 15, 30, 45, and 60 s, or for 0.5 min, with sampling at 15 s (n = 4). With 1.5-min cord clamping, an asphyxial state (Po2 < 10 mmHg) was evident at ≥45 s, with bradycardia and marked falls in LV and RV outputs (by 60% and 50%, P < 0.001), followed after ventilation onset by tachycardia and LV and RV output surges (4- and 3-fold, P < 0.001). By contrast, heart rate and outputs remained stable after 0.5-min cord clamping, with no postventilation change in heart rate or RV output, and a lesser rise in LV output (22%, P < 0.005). In preterm lambs, rapid development of an asphyxial state within 45 s in the cord clamp-to-ventilation interval increased hemodynamic lability of the birth transition, which was reduced with a shorter (∼0.5 min) cord clamp-to-ventilation interval. Copyright © 2015 the American Physiological Society.

  15. Surface characterization of selected LDEF tray clamps

    NASA Technical Reports Server (NTRS)

    Cromer, T. F.; Grammer, H. L.; Wightman, J. P.; Young, Philip R.; Slemp, Wayne S.

    1993-01-01

    The surface characterization of chromic acid anodized 6061-T6 aluminum alloy tray clamps has shown differences in surface chemistry depending upon the position on the Long Duration Exposure Facility (LDEF). Water contact angle results showed no changes in wettability of the tray clamps. The overall surface topography of the control, trailing edge(E3) and leading edge(D9) samples was similar. The thickness of the aluminum oxide layer for all samples determined by Auger depth profiling was less than one micron. X-ray photoelectron spectroscopy (XPS) analysis of the tray clamps showed significant differences in the surface composition. Carbon and silicon containing compounds were the primary contaminants detected.

  16. Aortic aneurysm repair - endovascular

    MedlinePlus

    ... Endovascular aneurysm repair - aorta; AAA repair - endovascular; Repair - aortic aneurysm - endovascular ... leaking or bleeding. You may have an abdominal aortic aneurysm that is not causing any symptoms or problems. ...

  17. Abdominal aortic aneurysm

    MedlinePlus

    ... page: //medlineplus.gov/ency/article/000162.htm Abdominal aortic aneurysm To use the sharing features on this page, ... to the abdomen, pelvis, and legs. An abdominal aortic aneurysm occurs when an area of the aorta becomes ...

  18. CT in aortic trauma

    SciTech Connect

    Heiberg, E.; Wolverson, M.K.; Sundaram, M.; Shields, J.B.

    1983-06-01

    A diagnosis of aortic transection was made at computed tomography (CT) in four of 10 patients with acute multiple trauma suspected of having thoracic aortic injuries. There were no false-negative or false-positive examinations. The CT findings of an injured aorta were (1) false aneurysm, (2) linear lucency within the opacified aortic lumen caused by the torn edge of the aortic wall, (3) marginal irregularity of the opacified aortic lumen, (4) periaortic or intramural aortic hematoma, and (5) dissection. The extent of associated mediastinal hemorrhage and the amount of blood in the pleural space were not useful as indicators of aortic injury. Similarly, shift of the trachea and esophagus or absence thereof was found in patients with or without aortic tear.

  19. Aortic dissection (image)

    MedlinePlus

    Aortic dissection is a condition in which there is bleeding into and along the wall of the aorta (the ... the inner wall of the artery. Although aortic dissection can affect anybody, it is most often seen ...

  20. Abdominal Aortic Aneurysm (AAA)

    MedlinePlus

    ... Professions Site Index A-Z Abdominal Aortic Aneurysm (AAA) Abdominal aortic aneurysm (AAA) occurs when atherosclerosis or plaque buildup causes the ... weak and bulge outward like a balloon. An AAA develops slowly over time and has few noticeable ...

  1. Regional aortic distensibility and its relationship with age and aortic stenosis: a computed tomography study.

    PubMed

    Wong, Dennis T L; Narayan, Om; Leong, Darryl P; Bertaso, Angela G; Maia, Murilo G; Ko, Brian S H; Baillie, Timothy; Seneviratne, Sujith K; Worthley, Matthew I; Meredith, Ian T; Cameron, James D

    2015-06-01

    Aortic distensibility (AD) decreases with age and increased aortic stiffness is independently associated with adverse cardiovascular outcomes. The association of severe aortic stenosis (AS) with AD in different aortic regions has not been evaluated. Elderly subjects with severe AS and a cohort of patients without AS of similar age were studied. Proximal aortic cross-sectional-area changes during the cardiac cycle were determined using retrospective-ECG-gating on 128-detector row computed-tomography. Using oscillometric-brachial-blood-pressure measurements, the AD at the ascending-aorta (AA), proximal-descending-aorta (PDA) and distal-descending-aorta (DDA) was determined. Linear mixed effects modelling was used to determine the association of age and aortic stenosis on regional AD. 102 patients were evaluated: 36 AS patients (70-85 years), 24 AS patients (>85 years) and 42 patients without AS (9 patients <50 years, 20 patients between 51-70 years and 13 patients 70-85 years). When comparing patients 70-85 years, AA distensibility was significantly lower in those with AS compared to those without AS (0.9 ± 0.9 vs. 1.4 ± 1.1, P = 0.03) while there was no difference in the PDA (1.0 ± 1.1 vs. 1.0 ± 1.2, P = 0.26) and DDA (1.1 ± 1.2 vs. 1.2 ± 0.8, P = 0.97). In patients without AS, AD decreased with age in all aortic regions (P < 0.001). The AA in patients <50 years were the most distensible compared to other aortic regions. There is regional variation in aortic distensibility with aging. Patients with aortic stenosis demonstrated regional differences in aortic distensibility with lower distensibility demonstrated in the proximal ascending aorta compared to an age-matched cohort.

  2. Dynamic clamp with StdpC software.

    PubMed

    Kemenes, Ildikó; Marra, Vincenzo; Crossley, Michael; Samu, Dávid; Staras, Kevin; Kemenes, György; Nowotny, Thomas

    2011-03-01

    Dynamic clamp is a powerful method that allows the introduction of artificial electrical components into target cells to simulate ionic conductances and synaptic inputs. This method is based on a fast cycle of measuring the membrane potential of a cell, calculating the current of a desired simulated component using an appropriate model and injecting this current into the cell. Here we present a dynamic clamp protocol using free, fully integrated, open-source software (StdpC, for spike timing-dependent plasticity clamp). Use of this protocol does not require specialist hardware, costly commercial software, experience in real-time operating systems or a strong programming background. The software enables the configuration and operation of a wide range of complex and fully automated dynamic clamp experiments through an intuitive and powerful interface with a minimal initial lead time of a few hours. After initial configuration, experimental results can be generated within minutes of establishing cell recording.

  3. Molecular Mechanisms of DNA Polymerase Clamp Loaders

    NASA Astrophysics Data System (ADS)

    Kelch, Brian; Makino, Debora; Simonetta, Kyle; O'Donnell, Mike; Kuriyan, John

    Clamp loaders are ATP-driven multiprotein machines that couple ATP hydrolysis to the opening and closing of a circular protein ring around DNA. This ring-shaped clamp slides along DNA, and interacts with numerous proteins involved in DNA replication, DNA repair and cell cycle control. Recently determined structures of clamp loader complexes from prokaryotic and eukaryotic DNA polymerases have revealed exciting new details of how these complex AAA+ machines perform this essential clamp loading function. This review serves as background to John Kuriyan's lecture at the 2010 Erice School, and is not meant as a comprehensive review of the contributions of the many scientists who have advanced this field. These lecture notes are derived from recent reviews and research papers from our groups.

  4. Clamp force and alignment checking device

    DOEpatents

    Spicer, John Patrick; Cai, Wayne W.; Chakraborty, Debejyo; Mink, Keith

    2017-04-11

    A check fixture measures a total clamp force applied by a welder device. The welder device includes a welding horn having a plurality of weld pads and welding anvil having a plurality of weld pads. The check fixture includes a base member operatively supporting a plurality of force sensors. The base member and the force sensors are received between the weld pads of the welding horn and the anvil pads of the welding anvil. Each force sensor is configured to measure an individual clamp force applied thereto by corresponding weld and anvil pads when the base member is received between the welding horn and the welding anvil and the welder device is in the clamped position. The individual clamp forces are used to determine whether the weld and/or anvil pads are worn or misaligned.

  5. Improved Algorithm for Automated Glucose Clamps.

    PubMed

    Kuhlenkötter, Mareike; Heise, Tim; Benesch, Carsten

    2017-02-01

    In glucose clamp experiments, blood glucose concentrations (BGs) are kept as close as possible to a predefined target level using variable glucose infusion rates (GIRs). In automated clamps, GIRs are calculated by algorithms implemented in the device (e.g., the Biostator). Low BG- and GIR-variability is needed for high clamp quality. We therefore tried to reduce oscillations in both BG and GIR with an improved algorithm implemented in ClampArt, a modern clamp device. The Biostator algorithm was first improved by numerical simulations of glucose clamps (in silico). With the results of the simulations, we started in vitro experiments using the ClampArt device and a container with water and glucose as "test subject." After a small pilot in vivo study, a larger clinical study was performed to compare the original with the optimized algorithm. With the improved algorithm, in silico, in vitro, and in vivo experiments showed reduced oscillations in both BG and GIR. In the clinical study, the coefficient of variation (CV) of BG values was lowered from 6.0% (4.6%-7.8%) [median (interquartile range)] to 4.2% (3.6%-5.0%), P < 0.0001 and the CV of GIR from 60.7% (49.6%-82.0%) to 43.5% (32.8%-57.2%), P < 0.0001. Other clamp quality parameters did not change substantially, median deviation from target slightly increased from 0.6% (0.2%-1.0%) to 1.1% (0.7%-1.5%), P = 0.0005, whereas utility did not change [97.0% (93.4%-100.0%) vs. 97.0% (94.0%-98.8%), P = 0.57]. With the improved algorithm, all experiments confirmed a reduction in BG- and GIR-oscillations without a major impact on other glucose clamp parameters. The optimized algorithm has been implemented in ClampArt for all future glucose clamp studies.

  6. Transcatheter aortic valve replacement

    MedlinePlus

    ... fully will restrict blood flow. This is called aortic stenosis. If there is also a leak, it is ... TAVR is used for people with severe aortic stenosis who aren't ... valve . In adults, aortic stenosis usually occurs due to calcium ...

  7. [Hiatal hernia incarceration during cardiopulmonary bypass in patient with acute aortic dissection--a case report].

    PubMed

    Hasegawa, Y; Saito, T; Horimi, H; Kato, M; Kawashima, T; Fuse, K

    1995-09-01

    A 67-year-old woman was admitted to our hospital under diagnosis of Stanford type A acute aortic dissection. Chest CT showed aortic dissection from the ascending to descending aorta, and large hiatal hernia. Operation was undergone under cardiopulmonary bypass and circulatory arrest with retrograde cerebral perfusion. A graft replacement was carried out from the ascending to transverse arch aorta. After the release of the cross-clamping of aorta, the heart was gradually oppressed anteriorly by extrapericardial mass, so that the patient could not be weaned from the cardiopulmonary bypass. The mass was revealed incarcerated hiatal hernia by ultrasonography. After laparotomy, diaphragm and hiatus were incised, the incarceration was relieved and the diaphgragm was repaired with a Goretex sheet. Then the patient could be weaned from cardiopulmonary bypass. Her postoperative course was uneventful except for acute renal failure, and she was discharged 60 days after the operation. The incarceration of hiatal hernia was thought to be caused by tissue edema and small bleeding during cardiopulmonary bypass. This is the first reported case with the incarceration of hiatal hernia which occurred during cardiopulmonary bypass.

  8. Erdosteine ameliorates lung injury induced by transient aortic occlusion in rats.

    PubMed

    Kurtoglu, Tunay; Sacar, Mustafa; Inan, Bilal Kaan; Duver, M Harun; Guler, Adem; Ucak, Alper; Us, Melih Hulusi; Yilmaz, Ahmet Turan

    2007-01-01

    The aim of this experimental study was to evaluate the protective effect of erdosteine on lung injury induced by ischaemia-reperfusion (IR) of the lower extremities of rats. Wistar albino rats (n = 21) were divided into three groups. In the IR group (n = 7), the aorta was cross-clamped for two hours, followed by one hour of reperfusion. In the erdosteine group (n = 7), animals were pretreated with erdosteine 100 mg/kg daily via gastric lavage, starting three days before aortic occlusion. In the control group (n 5 7), the lungs were removed and blood samples were taken immediately after sternotomy. No treatment was given in the control and IR groups. After both lungs were removed, biochemical parameters were measured and broncho-alveolar lavage (BAL ) assessment was made. MDA levels and MPO activities in the lung tissue were significantly reduced in the erdosteine group compared to the IR group. BAL assessment revealed decreased neutrophil counts in the erdosteine-treated group. Pretreatment of animals with erdosteine significantly attenuated transient aortic occlusion-induced remote lung injury, characterised by leukocyte accumulation and lipid peroxidation. The results suggest that erdosteine may be beneficial in amelioration of lung injury caused by IR.

  9. Structural analysis of a eukaryotic sliding DNA clamp-clamp loadercomplex.

    SciTech Connect

    Bowman, Gregory D.; O'Donnell, Mike; Kuriyan, John

    2006-06-17

    Sliding clamps are ring-shaped proteins that encircle DNA and confer high processivity on DNA polymerases. Here we report the crystal structure of the five-protein clamp loader complex (replication factor-C, RFC) of the yeast Saccharomyces cerevisiae, bound to the sliding clamp (proliferating cell nuclear antigen, PCNA). Tight interfacial coordination of the ATP analogue ATP-?-S by RFC results in a spiral arrangement of the ATPase domains of the clamp loader above the PCNA ring. Placement of a model for primed DNA within the central hole of PCNA reveals a striking correspondence between the RFC spiral and the grooves of the DNA double helix. This model, in which the clamp loader complex locks onto primed DNA in a screw-cap-like arrangement, provides a simple explanation for the process by which the engagement of primer-template junctions by the RFC:PCNA complex results in ATP hydrolysis and release of the sliding clamp on DNA.

  10. Diverless pipeline repair clamp: Phase 1

    SciTech Connect

    Miller, J.E.; Knott, B. )

    1991-12-01

    Offshore oil and gas developments are underway for water depths beyond which divers can function. The economic lifelines of these projects are the pipelines which will transport the products to shore. In preparation for the day when one of these pipelines will require repair because of a leak, the Pipeline Research Committee of the American Gas Association is funding research directed at developing diverless pipeline repair capabilities. Several types of damage are possible, ranging from latent weld defects on one end of the spectrum to damage resulting in parting of the pipe at the other end. This study is specifically directed toward laying the groundwork for development of a diverless pipeline repair clamp for use in repair of leaks resulting from minor pipe defects. The incentive for a clamp type repair is costs. When compared to replacing a section of pipe, either by welding or by mechanical means, the clamp type repair requires much less disturbance of the pipe, less time, fewer operations and less equipment. This report summarizes (1) capabilities of remotely operated vehicles (ROV's) and associated systems, (2) highlights areas for further research and development, (3) describes the required capabilities of the diverless repairclamp, (4) investigates some alternatives to the diverless clamp, (5) overviews the state of the art in leak repair clamps, and (6) critiques several possible generic clamp concepts.

  11. Sound absorption by clamped poroelastic plates.

    PubMed

    Aygun, H; Attenborough, K

    2008-09-01

    Measurements and predictions have been made of the absorption coefficient and the surface acoustic impedance of poroelastic plates clamped in a large impedance tube and separated from the rigid termination by an air gap. The measured and predicted absorption coefficient and surface impedance spectra exhibit low frequency peaks. The peak frequencies observed in the absorption coefficient are close to those predicted and measured in the deflection spectra of the clamped poroelastic plates. The influences of the rigidity of the clamping conditions and the width of the air gap have been investigated. Both influences are found to be important. Increasing the rigidity of clamping reduces the low frequency absorption peaks compared with those measured for simply supported plates or plates in an intermediate clamping condition. Results for a closed cell foam plate and for two open cell foam plates made from recycled materials are presented. For identical clamping conditions and width of air gap, the results for the different materials differ as a consequence mainly of their different elasticity, thickness, and cell structure.

  12. Transperitoneal repair of a juxtarenal abdominal aortic aneurysm and co-existent horseshoe kidney with division of the renal isthmus

    PubMed Central

    Hajibandeh, Shahin; Hajibandeh, Shahab; Johnpulle, Michelle; Perricone, Vittorio

    2015-01-01

    The co-existence of abdominal aortic aneurysm (AAA) and horseshoe kidney (HSK) is rare. We report a 67-year-old man with an expanding juxtarenal AAA associated with a HSK. The aneurysm had a severely angulated neck and contained a significant amount of mural thrombus. The isthmus of HSK closely lied over the aneurysm, making its exposure extremely difficult. The aneurysm was successfully repaired using transperitoneal approach with division of the renal isthmus and without any need for the renal artery reconstruction. Despite the potential complications, particularly renal insufficiency, associated with division of the renal isthmus and suprarenal cross-clamping of the abdominal aorta, in our case, post-operative period was uneventful and the patient's recovery was satisfactory. PMID:26511935

  13. Transcatheter aortic valve implantation.

    PubMed

    Oliemy, Ahmed; Al-Attar, Nawwar

    2014-01-01

    Transcatheter aortic valve implantation was developed to offer a therapeutic solution to patients with severe symptomatic aortic stenosis who are not candidates for conventional aortic valve replacement. The improvement in transcatheter aortic valve implantation outcomes is still of concern in the areas of stroke, vascular injury, heart block, paravalvular regurgitation and valve durability. Concomitantly, the progress, both technical and in terms of material advances of transcatheter valve systems, as well as in patient selection, renders transcatheter aortic valve implantation an increasingly viable treatment for more and more patients with structural heart disease.

  14. Depressed Systemic Arterial Compliance is Associated with the Severity of Heart Failure Symptoms in Moderate-to-Severe Aortic Stenosis: a Cross-Sectional Retrospective Study

    PubMed Central

    Kruszelnicka, Olga; Chmiela, Mark; Bobrowska, Beata; Świerszcz, Jolanta; Bhagavatula, Seetha; Bednarek, Jacek; Surdacki, Andrzej; Nessler, Jadwiga; Hryniewiecki, Tomasz

    2015-01-01

    Background: Patients with aortic stenosis (AS) may develop heart failure even in the absence of severe valve stenosis. Our aim was to assess the contribution of systemic arterial properties and the global left ventricular afterload to graded heart failure symptoms in AS. Methods: We retrospectively reviewed medical records of 157 consecutive subjects (mean age, 71±10 years; 79 women and 78 men) hospitalized owing to moderate-to-severe degenerative AS. Exclusion criteria included more than mild aortic insufficiency or disease of another valve, atrial fibrillation, coronary artery disease, severe respiratory disease or anemia. Heart failure symptoms were graded by NYHA class at admission. Systemic arterial compliance (SAC) and valvulo-arterial impedance (Zva) were derived from routine echocardiography and blood pressure. Results: Sixty-one patients were asymptomatic, 49 presented mild (NYHA II) and 47 moderate-to-severe (NYHA III-IV) heart failure symptoms. Mild symptoms were associated with lower SAC and transvalvular gradients, while more severe exercise intolerance coincided with older age, lower systolic blood pressure, smaller aortic valve area and depressed ejection fraction. By multiple ordinal logistic regression, the severity of heart failure symptoms was related to older age, depressed ejection fraction and lower SAC. Each decrease in SAC by 0.1 ml/m² per mmHg was associated with an increased adjusted odds ratio (OR) of a patient being in one higher category of heart failure symptoms graded as no symptoms, mild exercise intolerance and advanced exercise intolerance (OR: 1.16 [95% CI, 1.01-1.35], P=0.045). Conclusions: Depressed SAC may enhance exercise intolerance irrespective of stenosis severity or left ventricular systolic function in moderate-to-severe AS. This finding supports the importance of non-valvular factors for symptomatic status in AS. PMID:26180511

  15. Aortic Valve Replacement: Treatment by Sternotomy versus Minimally Invasive Approach

    PubMed Central

    Ferreira, Renata Tosoni Rodrigues; Silva, Roberto Rocha e; Marchi, Evaldo

    2016-01-01

    Objective To compare the results of aortic valve replacement with access by sternotomy or minimally invasive approach. Methods Retrospective analysis of medical records of 37 patients undergoing aortic valve replacement by sternotomy or minimally invasive approach, with emphasis on the comparison of time of cardiopulmonary bypass and aortic clamping, volume of surgical bleeding, time of mechanical ventilation, need for blood transfusion, incidence of atrial fibrillation, length of stay in intensive care unit, time of hospital discharge, short-term mortality and presence of surgical wound infection. Results Sternotomy was used in 22 patients and minimally invasive surgery in 15 patients. The minimally invasive approach had significantly higher time values of cardiopulmonary bypass (114.3±23.9 versus 86.7±19.8min.; P=0.003), aortic clamping (87.4±19.2 versus 61.4±12.9 min.; P<0.001) and mechanical ventilation (287.3±138.9 versus 153.9±118.6 min.; P=0.003). No difference was found in outcomes surgical bleeding volume, need for blood transfusion, incidence of atrial fibrillation, length of stay in intensive care unit and time of hospital discharge. No cases of short-term mortality or surgical wound infection were documented. Conclusion The less invasive approach presented with longer times of cardiopulmonary bypass, aortic clamping and mechanical ventilation than sternotomy, however without prejudice to the length of stay in intensive care unit, time of hospital discharge and morbidity. PMID:28076618

  16. Whole body perfusion for hybrid aortic arch repair: evolution of selective regional perfusion with a modified extracorporeal circuit.

    PubMed

    Fernandes, Philip; Walsh, Graham; Walsh, Stephanie; O'Neil, Michael; Gelinas, Jill; Chu, Michael W A

    2017-04-01

    Patients undergoing hybrid aortic arch reconstruction require careful protection of vital organs. We believe that whole body perfusion with tailored dual circuitry may help to achieve optimal patient outcomes. Our circuit has evolved from a secondary circuit utilizing a cardioplegia delivery device for lower body perfusion to a dual-oxygenator circuit. This allows individually controlled regional perfusion with ease of switching from secondary to primary circuit for total body flow. The re-design allows for separate flow and temperature regulation with two oxygenators in parallel. All patients underwent a single-stage operation for simultaneous treatment of arch and descending aortic pathology via a sternotomy, using a hybrid frozen elephant trunk technique. We report six consecutive patients undergoing hybrid arch and frozen elephant trunk reconstruction using a dual-oxygenator circuit. Five patients underwent elective surgery and one was emergent. One patient had an acute dissection while three underwent concomitant procedures, including a Ross procedure and two valve-sparing root reconstructions. Three cases were redo sternotomies. The mean pump time was 358 ± 131 min, the aortic cross clamp time 243 ± 135 min, the cardioplegia volume of 33,208 ml ± 16,173, cerebral ischemia 0 min, lower body ischemia 76 ± 34 min and the average lower body perfusion time was 142 min. Two patients did not require any donor blood products. The median intensive care unit (ICU) and hospital lengths of stay (LOS) were two days and 10 days, respectively. The average peak serum lactate on CPB was 7.47 mmol/L and, at admission to the ICU, it was 3.37 mmol/L. Renal and respiratory failure developed in the salvage acute type A dissection patient. No other complications occurred in this series. Whole body perfusion as delivered through individually controlled dual-oxygenator circuitry allows maximum flexibility for hybrid aortic arch reconstruction. A modified circuit perfusion

  17. Potassium Chloride Versus Voltage Clamp Contractures in Ventricular Muscle

    NASA Astrophysics Data System (ADS)

    Morad, M.; Reeck, S.; Rao, M.

    1981-01-01

    In frog ventricle, developed tension was markedly larger in response to depolarization caused by a voltage clamp step than to depolarization induced by high concentrations of potassium chloride. Measurement of extracellular potassium activity at the surface and at the depth of muscle during the development of contractures showed that the diffusion of potassium is much slower than the spread of depolarization through the cross section of muscle. These two observations suggest that competition between the depolarizing and the negative inotropic effects of an increase in the extracellular potassium ion concentration may determine the time course and magnitude of contractile tension in heart muscle.

  18. Replacement of the transverse aortic arch during emergency operations for type A acute aortic dissection. Report of 26 cases.

    PubMed

    Bachet, J; Teodori, G; Goudot, B; Diaz, F; el Kerdany, A; Dubois, C; Brodaty, D; de Lentdecker, P; Guilmet, D

    1988-12-01

    In type A aortic dissection, the intimal disruption is located on or extends to the transverse arch in about 20% of patients. Replacement of the arch may then be necessary to avoid leaving an unresected, acutely dissected aorta and to prevent bleeding, progression of aneurysm, rupture, and ultimately reoperation or death. From 1970 to September 1987, 119 patients were operated on for type A acute dissection. Starting in January 1977, gelatin-resorcin-formaldehyde biologic glue was used in 91 patients to reinforce the dissected tissues at the suture sites. Among these 119 patients, 26 (ages 32 to 76 years) underwent replacement of the transverse aortic arch in addition to replacement of the ascending aorta. In 20 patients cerebral protection was achieved by profound hypothermia (16 degrees to 20 degrees C) associated with circulatory arrest (15 to 40 minutes, mean 27 minutes) during the distal anastomosis. In six patients the carotid arteries were selectively perfused with cold blood (6 degrees C) during moderate core hypothermia (28 degrees C) while cardiopulmonary bypass was discontinued (19 to 34 minutes, mean 25 minutes) to allow the prosthesis to be sutured without the distal aorta being cross-clamped. Moderate hypothermia avoided the long rewarming time necessitated by profound hypothermia. The hospital mortality rate was 34% (9/26). Two of the 20 patients subjected to profound hypothermia and circulatory arrest died during the operation and seven patients died of postoperative complications. No deaths or major complication were observed in the other six patients. Follow-up of the 17 survivors ranges from 3 to 90 months (mean 39). One patient died 6 months after the operation of cerebral hemorrhage. One patient is disabled by neurologic sequelae. Fifteen patients are in good clinical condition (New York Heart Association class I or II). Postoperative aortograms in 12 patients, and computed tomographic scans in all, have shown a stable repair of the transverse

  19. There's an app for that: A handheld smartphone-based infrared imaging device to assess adequacy and level of aortic occlusion during REBOA.

    PubMed

    Sokol, Kyle K; Black, George E; Willey, Sandra B; Kniery, Kevin; Marko, Shannon T; Eckert, Matthew J; Martin, Matthew J

    2017-01-01

    Advances in thermal imaging devices have made them an appealing noninvasive point-of-care imaging adjunct in the trauma setting. We sought to assess whether a smartphone-based infrared imaging device (SBIR) could determine presence and location of aortic occlusion in a swine model. We hypothesized that various levels of aortic occlusion would transmit significantly different heat signatures at various anatomical points. Six swine (35-50 kg) underwent sequential zone 1 (Z1) aortic cross clamping as well as zone 3 (Z3) aortic balloon occlusion (resuscitative endovascular balloon occlusion of the aorta [REBOA]). SBIR images and readings (FLIR One) were taken at five anatomic points (axilla [A], subcostal [S], umbilical [U], inguinal [I], medial malleolar [M]) and were used to determine significant thermal trends 5 minutes to 10 minutes after Z1 and Z3 occlusion. Significant (p ≤ 0.05) thermal ratio patterns were identified and compared among groups, and images were reviewed for obvious qualitative differences at the various levels of occlusion. Body temperatures were similar during control (CON), Z1 occlusion, and Z3 occlusion, ranging from 94.0 °F to 100.9 °F (p = 0.126). No significant temperature differences were found among A, S, U, I, M points prior to and after aortic occlusions. Among the anatomical 2-point ratios evaluated, A/M and S/M ratios were the best predictors of aortic occlusion, whether at Z1 (8.2 °F, p < 0.01; 10.9 °F, p < 0.01) or Z3 (7.3 °F, p < 0.01; 8.4 °F, p < 0.01), respectively. The best predictor of Z1 versus Z3 level of occlusion was the S/I ratio (5.2 °F, p < 0.05 vs. 3.4 °F, p = 0.27). SBIR generated qualitatively different thermal signatures among groups. SBIR was capable of detecting thermal trends during Z1 and Z3 aortic occlusion by using an anatomical 2-point thermal ratio. There were also easily recognized qualitative differences between control and occlusion images that would allow immediate determination of adequate

  20. 30 CFR 18.40 - Cable clamps and grips.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Cable clamps and grips. 18.40 Section 18.40... Requirements § 18.40 Cable clamps and grips. Insulated clamps shall be provided for all portable (trailing) cables to prevent strain on the cable terminals of a machine. Also insulated clamps shall be provided to...

  1. 30 CFR 18.40 - Cable clamps and grips.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Cable clamps and grips. 18.40 Section 18.40... Requirements § 18.40 Cable clamps and grips. Insulated clamps shall be provided for all portable (trailing) cables to prevent strain on the cable terminals of a machine. Also insulated clamps shall be provided to...

  2. 30 CFR 18.40 - Cable clamps and grips.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Cable clamps and grips. 18.40 Section 18.40... Requirements § 18.40 Cable clamps and grips. Insulated clamps shall be provided for all portable (trailing) cables to prevent strain on the cable terminals of a machine. Also insulated clamps shall be provided to...

  3. 21 CFR 882.4460 - Neurosurgical head holder (skull clamp).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Neurosurgical head holder (skull clamp). 882.4460... holder (skull clamp). (a) Identification. A neurosurgical head holder (skull clamp) is a device used to clamp the patient's skull to hold head and neck in a particular position during surgical procedures....

  4. 21 CFR 882.4460 - Neurosurgical head holder (skull clamp).

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Neurosurgical head holder (skull clamp). 882.4460... holder (skull clamp). (a) Identification. A neurosurgical head holder (skull clamp) is a device used to clamp the patient's skull to hold head and neck in a particular position during surgical procedures....

  5. 21 CFR 882.4460 - Neurosurgical head holder (skull clamp).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Neurosurgical head holder (skull clamp). 882.4460... holder (skull clamp). (a) Identification. A neurosurgical head holder (skull clamp) is a device used to clamp the patient's skull to hold head and neck in a particular position during surgical procedures....

  6. 21 CFR 882.4460 - Neurosurgical head holder (skull clamp).

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Neurosurgical head holder (skull clamp). 882.4460... holder (skull clamp). (a) Identification. A neurosurgical head holder (skull clamp) is a device used to clamp the patient's skull to hold head and neck in a particular position during surgical procedures....

  7. 21 CFR 882.4460 - Neurosurgical head holder (skull clamp).

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Neurosurgical head holder (skull clamp). 882.4460... holder (skull clamp). (a) Identification. A neurosurgical head holder (skull clamp) is a device used to clamp the patient's skull to hold head and neck in a particular position during surgical procedures....

  8. Comparison of Transcranial Motor Evoked Potentials and Somatosensory Evoked Potentials During Thoracoabdominal Aortic Aneurysm Repair

    PubMed Central

    Meylaerts, Sven A.; Jacobs, Michael J.; van Iterson, Vincent; De Haan, Peter; Kalkman, Cor J.

    1999-01-01

    Objective To compare transcranial motor evoked potentials (tc-MEPs) and somatosensory evoked potentials (SSEPs) as indicators of spinal cord function during thoracoabdominal aortic aneurysm repair. Summary Background Data Somatosensory evoked potentials reflect conduction in dorsal columns. tc-MEPs represent anterior horn motor neuron function. This is the first study to compare the techniques directly during thoracoabdominal aortic aneurysm repair. Methods In 38 patients, thoracoabdominal aortic aneurysm repair (type I, n = 10, type II, n = 14, type III, n = 6, type IV, n = 8) was performed using left heart bypass and segmental artery reimplantation. tc-MEP amplitudes <25% and SSEP amplitudes <50% and/or latencies >110% were considered indicators of cord ischemia. The authors compared the response of both methods to interventions and correlated the responses at the end of surgery to neurologic outcomes. Results Ischemic tc-MEP changes occurred in 18/38 patients and could be restored by segmental artery reperfusion (n = 12) or by increasing blood pressure (n = 6). Significant SSEP changes accompanied these tc-MEP events in only 5/18 patients, with a delay of 2 to 34 minutes. SSEPs recovered in only two patients. In another 11 patients, SSEP amplitudes fell progressively to <50% of control without parallel tc-MEP changes or association with cross-clamp events or pressure decreases. At the end of the procedure, tc-MEP amplitudes were 84 ± 46% of control. In contrast, SSEP amplitudes were <50% of control in 15 patients (39%). No paraplegia occurred. Conclusion In all patients, tc-MEP events could be corrected by applying protective strategies. No patient awoke paraplegic. SSEPs showed delayed ischemia detection and a high rate of false-positive results. PMID:10615928

  9. Piezoresistive cantilever force-clamp system

    SciTech Connect

    Park, Sung-Jin; Petzold, Bryan C.; Pruitt, Beth L.; Goodman, Miriam B.

    2011-04-15

    We present a microelectromechanical device-based tool, namely, a force-clamp system that sets or ''clamps'' the scaled force and can apply designed loading profiles (e.g., constant, sinusoidal) of a desired magnitude. The system implements a piezoresistive cantilever as a force sensor and the built-in capacitive sensor of a piezoelectric actuator as a displacement sensor, such that sample indentation depth can be directly calculated from the force and displacement signals. A programmable real-time controller operating at 100 kHz feedback calculates the driving voltage of the actuator. The system has two distinct modes: a force-clamp mode that controls the force applied to a sample and a displacement-clamp mode that controls the moving distance of the actuator. We demonstrate that the system has a large dynamic range (sub-nN up to tens of {mu}N force and nm up to tens of {mu}m displacement) in both air and water, and excellent dynamic response (fast response time, <2 ms and large bandwidth, 1 Hz up to 1 kHz). In addition, the system has been specifically designed to be integrated with other instruments such as a microscope with patch-clamp electronics. We demonstrate the capabilities of the system by using it to calibrate the stiffness and sensitivity of an electrostatic actuator and to measure the mechanics of a living, freely moving Caenorhabditis elegans nematode.

  10. An Ultrasonic Clamp for Bloodless Partial Nephrectomy

    NASA Astrophysics Data System (ADS)

    Lafon, Cyril; Bouchoux, Guillaume; Murat, François Joseph; Birer, Alain; Theillère, Yves; Chapelon, Jean Yves; Cathignol, Dominique

    2007-05-01

    Maximum conservation of the kidney is preferable through partial nephrectomy for patients at risk of disease recurrence of renal cancers. Haemostatic tools are needed in order to achieve bloodless surgery and reduce post surgery morbidity. Two piezo-ceramic transducers operating at a frequency of 4 MHz were mounted on each arm of a clamp. When used for coagulation purposes, two transducers situated on opposite arms of the clamp were driven simultaneously. Heat delivery was optimized as each transducers mirrored back to targeted tissues the wave generated by the opposite transducer. Real-time treatment monitoring with an echo-based technique was also envisaged with this clamp. Therapy was periodically interrupted so one transducer could generate a pulse. The echo returning from the opposite transducer was treated. Coagulation necroses were obtained in vitro on substantial thicknesses (23-38mm) of pig liver over exposure durations ranging from 30s to 130s, and with acoustic intensities of less than 15W/cm2 per transducer. Both kidneys of two pigs were treated in vivo with the clamp (14.5W/cm2 for 90s), and the partial nephrectomies performed proved to be bloodless. In vitro and in vivo, wide transfixing lesions corresponded to an echo energy decrease superior to -10dB and parabolic form of the time of flight versus treatment time. In conclusion, this ultrasound clamp has proven to be an excellent mean for achieving monitored haemostasis in kidney.

  11. Compact, Stiff, Remotely-Actuable Quick-Release Clamp

    NASA Technical Reports Server (NTRS)

    Tsai, Ted W. (Inventor)

    2000-01-01

    The present invention provides a clamp that is compact and lightweight, yet provides high holding strength and stiffness or rigidity. The clamp uses a unique double slant interface design which provides mechanical advantages to resist forces applied to the clamp member as the load increases. The clamp allows for rapid and remote-activated release of the clamp jaws by applying only a small operating force to an over-center lock/release mechanism, such as by pulling a manual tether.

  12. History of electrophysiology and the patch clamp.

    PubMed

    Verkhratsky, Alexei; Parpura, Vladimir

    2014-01-01

    We provide a historic outlook on the development of the concept of bioelectricity, with emphasis on the neuromuscular junction as a model that revolutionized our thinking of the nerve, nervous, and muscle tissue excitability. We abridge some crucial experiments in defining the electrical excitability of biological cells. We also provide an insight into developments of tools and methods, which gradually yielded a contemporary "palette" of electrophysiology approaches, including the patch clamp. Pioneering steps in this journey, ranging from Galvani's experiments using the Leyden jar to those of Neher and Sakmann using a gigaseal patch-clamp approach, are pictorially illustrated. This chapter is meant to be a perspective to the following sections in this volume dedicated to patch-clamp methods and protocols.

  13. Supravalvular aortic stenosis in adult with anomalies of aortic arch vessels and aortic regurgitation

    PubMed Central

    Valente, Acrisio Sales; Alencar, Polyanna; Santos, Alana Neiva; Lobo, Roberto Augusto de Mesquita; de Mesquita, Fernando Antônio; Guimarães, Aloyra Guedis

    2013-01-01

    The supravalvular aortic stenosis is a rare congenital heart defect being very uncommon in adults. We present a case of supravalvular aortic stenosis in adult associated with anomalies of the aortic arch vessels and aortic regurgitation, which was submitted to aortic valve replacement and arterioplasty of the ascending aorta with a good postoperative course. PMID:24598962

  14. Measurement of aortic regurgitation by Doppler echocardiography.

    PubMed Central

    Zhang, Y; Nitter-Hauge, S; Ihlen, H; Rootwelt, K; Myhre, E

    1986-01-01

    In an attempt to develop a new approach to the non-invasive measurement of aortic regurgitation, transmitral volumetric flow (MF) and left ventricular total stroke volume (SV) were measured by Doppler and cross sectional echocardiography in 23 patients without aortic valve disease (group A) and in 26 patients with aortic regurgitation (group B). The transmitral volumetric flow was obtained by multiplying the corrected mitral orifice area by the diastolic velocity integral, and the left ventricular total stroke volume was derived by subtracting the left ventricular end systolic volume from the end diastolic volume. The aortic regurgitant fraction (RF) was calculated as: RF = 1 - MF/SV. In group A there was a close agreement between the transmitral volumetric flow and the left ventricular total stroke volume, and the difference between the two measurements did not differ significantly from zero. In group B the left ventricular total stroke volume was significantly larger than the transmitral volumetric flow, and there was good agreement between the regurgitant fractions determined by Doppler echocardiography and radionuclide ventriculography. Discrepancies between the two techniques were found in patients with combined aortic and mitral regurgitation or a low angiographic left ventricular ejection fraction (less than 35%). The effective cardiac output measured by Doppler echocardiography accorded well with that measured by the Fick method. Doppler echocardiography provides a new and promising approach to the non-invasive measurement of aortic regurgitation. PMID:3947478

  15. Perspectives on implementing delayed cord clamping.

    PubMed

    Leslie, Mayri Sagady

    2015-01-01

    Expanding evidence supports delayed cord clamping (DCC) for both term and preterm infants. This article explores issues that may be keeping early cord clamping (ECC) in place as usual practice. Professional organizations almost universally recommend DCC for preterm infants, but some reserve recommending it for term infants only in resource-poor settings. Concerns about polycythemia and jaundice persist in the literature, while years of published randomized controlled trials do not support the assumptions behind the concerns. New data suggest that DCC may improve resuscitative efforts in compromised infants. Multiple perspectives are offered for consideration when thinking about incorporating DCC into practice. © 2015 AWHONN.

  16. Aortic valve surgery - minimally invasive

    MedlinePlus

    ... of the heart is reduced. This is called aortic stenosis. The aortic valve can be replaced using: Minimally ... RN, Wang A. Percutaneous heart valve replacement for aortic stenosis: state of the evidence. Ann Intern Med . 2010; ...

  17. [Surgery repair of aortic coarctation in infancy].

    PubMed

    Acevedo-Bañuelos, Iliana; González-Peña, Javier; Chagolla-Santillán, Miguel Ángel; Hernández-Morales, Gunter; Farías-Serratos, Claudia Vianey

    2013-01-01

    The study's purpose is to present our experience with surgical correction of aortic coarctation in infants, at short and medium term, particularly morbidity and mortality. This is a retrospective observational and descriptive trial. We included all infant patients undergoing surgical correction of AC. All data were obtained from the clinical database of the hospital. We included 20 patients with AC. The surgical technique was extended coarctectomy in 19 patients and, in one patient, a subclavian artery flap was performed. In all patients, the average time of aortic clamping was 18min. The residual gradient measured by echocardiography was in average of 12.2mmHg. One patient died of sepsis secondary to pneumonia. The main cause of immediate postoperative morbidity was systemic hypertension in seven patients, nosocomial infection in four patients with development of sepsis, one patient had to be reoperated due to high gradient. One patient had cholestatic syndrome. Eighteen patients required a transfusion at some time during their hospital stay. Average in-hospital stay was of 12 days. The aortic coarctation surgery has had favorable results so far and we can conclude that the program has been successful. The surgical technique has shown low mortality and complications and midterm follow-up shows low rate of recoarctation. Copyright © 2012 Instituto Nacional de Cardiología Ignacio Chávez. Published by Masson Doyma México S.A. All rights reserved.

  18. Bicuspid Aortic Valve

    DTIC Science & Technology

    2006-08-01

    Schnell E, Wollenek G, Maurer G, Baumgartner H, Lang IM. Mechanisms underlying aortic dilatation in congenital aortic valve malformation . Circulation...1999; 99(16):2138-2143. 10. Roberts CS, Roberts WC. Dissection of the aorta associated with congenital malformation of the aortic valve. J Am Coll... congenital heart defect, often diagnosed incidentally or as a consequence of an associated condition. Patients with this anomaly are at increased risk

  19. Kinetic analysis of PCNA clamp binding and release in the clamp loading reaction catalyzed by Saccharomyces cerevisiae replication factor C

    PubMed Central

    Marzahn, Melissa R.; Hayner, Jaclyn N.; Meyer, Jennifer A.; Bloom, Linda B.

    2014-01-01

    DNA polymerases require a sliding clamp to achieve processive DNA synthesis. The toroidal clamps are loaded onto DNA by clamp loaders, members of the AAA+ family of ATPases. These enzymes utilize the energy of ATP binding and hydrolysis to perform a variety of cellular functions. In this study, a clamp loader-clamp binding assay was developed to measure the rates of ATP-dependent clamp binding and ATP-hydrolysis-dependent clamp release for the S. cerevisiae clamp loader (RFC) and clamp (PCNA). Pre-steady-state kinetics of PCNA binding showed that although ATP binding to RFC increases affinity for PCNA, ATP binding rates and ATP-dependent conformational changes in RFC are fast relative to PCNA binding rates. Interestingly, RFC binds PCNA faster than the Escherichia coli γ complex clamp loader binds the β-clamp. In the process of loading clamps on DNA, RFC maintains contact with PCNA while PCNA closes, as the observed rate of PCNA closing is faster than the rate of PCNA release, precluding the possibility of an open clamp dissociating from DNA. Rates of clamp closing and release are not dependent on the rate of the DNA binding step and are also slower than reported rates of ATP hydrolysis, showing that these rates reflect unique intramolecular reaction steps in the clamp loading pathway. PMID:25450506

  20. Kinetic analysis of PCNA clamp binding and release in the clamp loading reaction catalyzed by Saccharomyces cerevisiae replication factor C.

    PubMed

    Marzahn, Melissa R; Hayner, Jaclyn N; Meyer, Jennifer A; Bloom, Linda B

    2015-01-01

    DNA polymerases require a sliding clamp to achieve processive DNA synthesis. The toroidal clamps are loaded onto DNA by clamp loaders, members of the AAA+family of ATPases. These enzymes utilize the energy of ATP binding and hydrolysis to perform a variety of cellular functions. In this study, a clamp loader-clamp binding assay was developed to measure the rates of ATP-dependent clamp binding and ATP-hydrolysis-dependent clamp release for the Saccharomyces cerevisiae clamp loader (RFC) and clamp (PCNA). Pre-steady-state kinetics of PCNA binding showed that although ATP binding to RFC increases affinity for PCNA, ATP binding rates and ATP-dependent conformational changes in RFC are fast relative to PCNA binding rates. Interestingly, RFC binds PCNA faster than the Escherichia coli γ complex clamp loader binds the β-clamp. In the process of loading clamps on DNA, RFC maintains contact with PCNA while PCNA closes, as the observed rate of PCNA closing is faster than the rate of PCNA release, precluding the possibility of an open clamp dissociating from DNA. Rates of clamp closing and release are not dependent on the rate of the DNA binding step and are also slower than reported rates of ATP hydrolysis, showing that these rates reflect unique intramolecular reaction steps in the clamp loading pathway.

  1. Limited versus full sternotomy for aortic valve replacement.

    PubMed

    Kirmani, Bilal H; Jones, Sion G; Malaisrie, S C; Chung, Darryl A; Williams, Richard Jnn

    2017-04-10

    , assess quality, and identify risk of bias. A third review author provided arbitration where required. The quality of evidence was determined using the GRADE methodology and results of patient-relevant outcomes were summarised in a 'Summary of findings' table. The review included seven trials with 511 participants. These included adults from centres in Austria, Spain, Italy, Germany, France, and Egypt. We performed 12 comparisons investigating the effects of minimally invasive limited upper hemi-sternotomy on aortic valve replacement as compared to surgery performed via full median sternotomy.There was no evidence of any effect of upper hemi-sternotomy on mortality versus full median sternotomy (risk ratio (RR) 1.01, 95% confidence interval (CI) 0.36 to 2.82; participants = 511; studies = 7; moderate quality). There was no evidence of an increase in cardiopulmonary bypass time with aortic valve replacement performed via an upper hemi-sternotomy (mean difference (MD) 3.02 minutes, 95% CI -4.10 to 10.14; participants = 311; studies = 5; low quality). There was no evidence of an increase in aortic cross-clamp time (MD 0.95 minutes, 95% CI -3.45 to 5.35; participants = 391; studies = 6; low quality). None of the included studies reported major adverse cardiac and cerebrovascular events as a composite end point.There was no evidence of an effect on length of hospital stay through limited hemi-sternotomy (MD -1.31 days, 95% CI -2.63 to 0.01; participants = 297; studies = 5; I(2) = 89%; very low quality). Postoperative blood loss was lower in the upper hemi-sternotomy group (MD -158.00 mL, 95% CI -303.24 to -12.76; participants = 297; studies = 5; moderate quality). The evidence did not support a reduction in deep sternal wound infections (RR 0.71, 95% CI 0.22 to 2.30; participants = 511; studies = 7; moderate quality) or re-exploration (RR 1.01, 95% CI 0.48 to 2.13; participants = 511; studies = 7; moderate quality). There was no change in pain scores by upper hemi

  2. Patch-clamping Drosophila sensory neurons.

    PubMed

    Kucher, Volodymyr; Eaton, Benjamin A; Stockand, James D; Boiko, Nina

    2013-01-01

    Electrophysiological studies provide essential clues about the regulation and physiological function of ion channel proteins. Probing ion channel activity in vivo, though, often is challenging. This can limit the usefulness of such model organisms as Drosophila for electrophysiological studies. This is unfortunate because these genetically tractable organisms represent powerful research tools that facilitate elaboration of complex questions of physiology. Here, we describe a recently developed method for recording ion channel activity in Drosophila sensory neurons. This approach is based on patch-clamping primary neuron cultures from Drosophila embryos. Such cultures allow the study of ion channels in different genetic backgrounds. In addition to describing how to prepare a primary neuronal cell culture from Drosophila embryos, we discuss, as an example of utility, analysis of Na(+) currents in cultured class IV multidendritic (md) sensory neurons with the patch clamp technique. Excitability of md sensory neurons, manifested as action potential firing, is revealed with whole-cell current-clamping. Voltage-clamping class IV md neurons revealed the activity of the voltage-gated Na(+) channel, paralytic. Moreover, challenging class IV md neurons with acidic pH activates acid-sensing inward Na(+) currents. Genetic manipulation of Drosophila combined with this electrophysiological readout of activity identifies pickpocket1 (Ppk1), a member of the Deg/ENaC channel family, as responsible for conducting an acid-sensing Na(+) current in class IV md sensory neurons.

  3. Limit analysis of pipe clamps. Revision 1

    SciTech Connect

    Flanders, H.E. Jr.

    1990-12-31

    The Service Level D (faulted) load capacity of a conventional three-bolt pipe-clamp based upon the limit analysis method is presented. The load distribution, plastic hinge locations, and collapse load are developed for the lower bound limit load method. The results of the limit analysis are compared with the manufacturer`s rated loads. 3 refs.

  4. Patch-clamp amplifiers on a chip.

    PubMed

    Weerakoon, Pujitha; Culurciello, Eugenio; Yang, Youshan; Santos-Sacchi, Joseph; Kindlmann, Peter J; Sigworth, Fred J

    2010-10-15

    We present the first, fully integrated, two-channel implementation of a patch-clamp measurement system. With this "PatchChip" two simultaneous whole-cell recordings can be obtained with rms noise of 8pA in a 10kHz bandwidth. The capacitance and series-resistance of the electrode can be compensated up to 10pF and 100MΩ respectively under computer control. Recordings of hERG and Na(v) 1.7 currents demonstrate the system's capabilities, which are on par with large, commercial patch-clamp instrumentation. By reducing patch-clamp amplifiers to a millimeter size micro-chip, this work paves the way to the realization of massively parallel, high-throughput patch-clamp systems for drug screening and ion-channel research. The PatchChip is implemented in a 0.5μm silicon-on-sapphire process; its size is 3×3mm(2) and the power consumption is 5mW per channel with a 3.3V power supply.

  5. Π-Clamp-mediated cysteine conjugation.

    PubMed

    Zhang, Chi; Welborn, Matthew; Zhu, Tianyu; Yang, Nicole J; Santos, Michael S; Van Voorhis, Troy; Pentelute, Bradley L

    2016-02-01

    Site-selective functionalization of complex molecules is one of the most significant challenges in chemistry. Typically, protecting groups or catalysts must be used to enable the selective modification of one site among many that are similarly reactive, and general strategies that selectively tune the local chemical environment around a target site are rare. Here, we show a four-amino-acid sequence (Phe-Cys-Pro-Phe), which we call the 'π-clamp', that tunes the reactivity of its cysteine thiol for site-selective conjugation with perfluoroaromatic reagents. We use the π-clamp to selectively modify one cysteine site in proteins containing multiple endogenous cysteine residues. These examples include antibodies and cysteine-based enzymes that would be difficult to modify selectively using standard cysteine-based methods. Antibodies modified using the π-clamp retained binding affinity to their targets, enabling the synthesis of site-specific antibody-drug conjugates for selective killing of HER2-positive breast cancer cells. The π-clamp is an unexpected approach to mediate site-selective chemistry and provides new avenues to modify biomolecules for research and therapeutics.

  6. Patch-clamp amplifiers on a chip

    PubMed Central

    Weerakoon, Pujitha; Culurciello, Eugenio; Yang, Youshan; Santos-Sacchi, Joseph; Kindlmann, Peter J.; Sigworth, Fred J.

    2010-01-01

    We present the first, fully-integrated, two-channel implementation of a patch-clamp measurement system. With this “PatchChip” two simultaneous whole-cell recordings can be obtained with rms noise of 8 pA in a 10 kHz bandwidth. The capacitance and series-resistance of the electrode can be compensated up to 10 pF and 100 MΩ respectively under computer control. Recordings of hERG and Nav 1.7 currents demonstrate the system's capabilities, which are on par with large, commercial patch-clamp instrumentation. By reducing patch-clamp amplifiers to a millimeter size micro-chip, this work paves the way to the realization of massively-parallel, high-throughput patch-clamp systems for drug screening and ion-channel research. The PatchChip is implemented in a 0.5 μm silicon-on-sapphire process; its size is 3 × 3 mm2 and the power consumption is 5 mW per channel with a 3.3 V power supply. PMID:20637803

  7. Clamp and Gas Nozzle for TIG Welding

    NASA Technical Reports Server (NTRS)

    Gue, G. B.; Goller, H. L.

    1982-01-01

    Tool that combines clamp with gas nozzle is aid to tungsten/inert-gas (TIG) welding in hard-to-reach spots. Tool holds work to be welded while directing a stream of argon gas at weld joint, providing an oxygen-free environment for tungsten-arc welding.

  8. FOXE3 mutations predispose to thoracic aortic aneurysms and dissections.

    PubMed

    Kuang, Shao-Qing; Medina-Martinez, Olga; Guo, Dong-Chuan; Gong, Limin; Regalado, Ellen S; Reynolds, Corey L; Boileau, Catherine; Jondeau, Guillaume; Prakash, Siddharth K; Kwartler, Callie S; Zhu, Lawrence Yang; Peters, Andrew M; Duan, Xue-Yan; Bamshad, Michael J; Shendure, Jay; Nickerson, Debbie A; Santos-Cortez, Regie L; Dong, Xiurong; Leal, Suzanne M; Majesky, Mark W; Swindell, Eric C; Jamrich, Milan; Milewicz, Dianna M

    2016-03-01

    The ascending thoracic aorta is designed to withstand biomechanical forces from pulsatile blood. Thoracic aortic aneurysms and acute aortic dissections (TAADs) occur as a result of genetically triggered defects in aortic structure and a dysfunctional response to these forces. Here, we describe mutations in the forkhead transcription factor FOXE3 that predispose mutation-bearing individuals to TAAD. We performed exome sequencing of a large family with multiple members with TAADs and identified a rare variant in FOXE3 with an altered amino acid in the DNA-binding domain (p.Asp153His) that segregated with disease in this family. Additional pathogenic FOXE3 variants were identified in unrelated TAAD families. In mice, Foxe3 deficiency reduced smooth muscle cell (SMC) density and impaired SMC differentiation in the ascending aorta. Foxe3 expression was induced in aortic SMCs after transverse aortic constriction, and Foxe3 deficiency increased SMC apoptosis and ascending aortic rupture with increased aortic pressure. These phenotypes were rescued by inhibiting p53 activity, either by administration of a p53 inhibitor (pifithrin-α), or by crossing Foxe3-/- mice with p53-/- mice. Our data demonstrate that FOXE3 mutations lead to a reduced number of aortic SMCs during development and increased SMC apoptosis in the ascending aorta in response to increased biomechanical forces, thus defining an additional molecular pathway that leads to familial thoracic aortic disease.

  9. FOXE3 mutations predispose to thoracic aortic aneurysms and dissections

    PubMed Central

    Kuang, Shao-Qing; Medina-Martinez, Olga; Guo, Dong-chuan; Gong, Limin; Regalado, Ellen S.; Reynolds, Corey L.; Boileau, Catherine; Jondeau, Guillaume; Prakash, Siddharth K.; Kwartler, Callie S.; Zhu, Lawrence Yang; Peters, Andrew M.; Duan, Xue-Yan; Bamshad, Michael J.; Shendure, Jay; Nickerson, Debbie A.; Santos-Cortez, Regie L.; Dong, Xiurong; Leal, Suzanne M.; Majesky, Mark W.; Swindell, Eric C.; Jamrich, Milan; Milewicz, Dianna M.

    2016-01-01

    The ascending thoracic aorta is designed to withstand biomechanical forces from pulsatile blood. Thoracic aortic aneurysms and acute aortic dissections (TAADs) occur as a result of genetically triggered defects in aortic structure and a dysfunctional response to these forces. Here, we describe mutations in the forkhead transcription factor FOXE3 that predispose mutation-bearing individuals to TAAD. We performed exome sequencing of a large family with multiple members with TAADs and identified a rare variant in FOXE3 with an altered amino acid in the DNA-binding domain (p.Asp153His) that segregated with disease in this family. Additional pathogenic FOXE3 variants were identified in unrelated TAAD families. In mice, Foxe3 deficiency reduced smooth muscle cell (SMC) density and impaired SMC differentiation in the ascending aorta. Foxe3 expression was induced in aortic SMCs after transverse aortic constriction, and Foxe3 deficiency increased SMC apoptosis and ascending aortic rupture with increased aortic pressure. These phenotypes were rescued by inhibiting p53 activity, either by administration of a p53 inhibitor (pifithrin-α), or by crossing Foxe3–/– mice with p53–/– mice. Our data demonstrate that FOXE3 mutations lead to a reduced number of aortic SMCs during development and increased SMC apoptosis in the ascending aorta in response to increased biomechanical forces, thus defining an additional molecular pathway that leads to familial thoracic aortic disease. PMID:26854927

  10. Dynamics and Stability of Pinned-Clamped and Clamped-Pinned Cylindrical Shells Conveying Fluid

    NASA Astrophysics Data System (ADS)

    Misra, A. K.; Wong, S. S. T.; Païdoussis, M. P.

    2001-11-01

    The paper examines the dynamics and stability of fluid-conveying cylindrical shells having pinned-clamped or clamped-pinned boundary conditions, where ``pinned'' is an abbreviation for ``simply supported''. Flügge's equations are used to describe the shell motion, while the fluid-dynamic perturbation pressure is obtained utilizing the linearized potential flow theory. The solution is obtained using two methods - the travelling wave method and the Fourier-transform approach. The results obtained by both methods suggest that the negative damping of the clamped-pinned systems and positive damping of the pinned-clamped systems, observed by previous investigators for any arbitrarily small flow velocity, are simply numerical artefacts; this is reinforced by energy considerations, in which the work done by the fluid on the shell is shown to be zero. Hence, it is concluded that both systems are conservative.

  11. Transcatheter aortic valve implantation in aortic coarctation.

    PubMed

    Schramm, René; Kupatt, Christian; Becker, Christoph; Bombien, René; Reichart, Bruno; Sodian, Ralf; Schmitz, Christoph

    2013-06-01

    A 77-year-old male patient was scheduled for transcatheter aortic valve implantation for symptomatic and severe aortic valve stenosis. Severe multidirectional kinking of the aorta based on aortic coarctation did not allow for the transfemoral, but only for the transapical approach. The procedure was complicated because of the technically challenging retrograde passage of the transfemorally inserted pig-tail catheter required for intraoperative angiography of the aortic root. Correct positioning of the pig-tail catheter into the ascending aorta was accomplished by use of a loop snare, which was advanced into the descending aorta via the antegrade route, passing the cardiac apex, the stenotic aortic valve, and the coarctation-associated kinking. The pig-tail catheter tip was manipulated into the loop snare, pulled traverse the coarctation, and released within the proximal ascending aorta. Subsequent procedures were uneventful and followed the standardized protocol. A 29 mm Edwards Lifescience transcatheter Sapien bioprosthesis was successfully implanted. Georg Thieme Verlag KG Stuttgart · New York.

  12. Aortic Valve Disease

    MedlinePlus

    ... body Watch the video below as Dr. Robbin Cohen describes aortic stenosis Video of Robbin G. Cohen, MD on Aortic Stenosis Causes and Symptoms Causes ... when having dental work. Reviewed by: Robbin G. Cohen, MD, with assistance from John Hallsten and Travis ...

  13. Use of two parallel oxygenators in a very large patient (2.76 m2) for an acute "A" dissecting aortic aneurysm repair.

    PubMed

    Lonský, Vladimir; Mand'ák, Jiri; Kubícek, Jaroslav; Volt, Martin; Procházka, Egon; Dominik, Jan

    2005-01-01

    The very large patient (weight 142 kg, height 197 cm, body surface 2.76 m2) was referred to acute operation with dissecting type A ascending aortic aneurysm. The calculated blood flow was 6.63 l/min. To anticipate potential difficulties with perfusion and oxygenation two oxygenators connected in parallel were incorporated into the circuit. Bentall procedure with ACB to the RCA was performed. The perfusion was uneventful. Bypass time was 259 minutes, cross clamp time 141 minutes, circulatory arrest 7 minutes. The highest oxygenators gas flow was 2.6 l/min with maximum FiO2 0.42. The use of two in parallel connected oxygenators is a very effective, easy and safe method in such extreme perfusions, offering to the perfusionist a great reserve of oxygenator output.

  14. A patent ductus arteriosus complicating cardiopulmonary bypass for combined coronary artery bypass grafting and aortic valve replacement only discovered by computed tomography 3D reconstruction.

    PubMed

    van Middendorp, Lars B; Maessen, Jos G; Sardari Nia, Peyman

    2014-12-01

    We describe the case of a 59-year old male patient undergoing combined coronary artery bypass grafting and aortic valve replacement. Manipulation of the heart during cardiopulmonary bypass significantly decreased venous return. Several measures were necessary to improve venous return to a level at which continuation of the procedure was safe. Based on the initial troubles with venous return, we decided to selectively cross-clamp the aorta. This resulted in a large amount of backflow of oxygenated blood from the left ventricle, necessitating additional vents in the pulmonary artery and directly in the left ventricle. The procedure was continued uneventfully, and postoperative recovery was without significant complications. Postoperative 2D computed tomography did not show any signs of a shunt, but 3D reconstruction showed a small patent ductus arteriosus.

  15. Stress softening and permanent deformation in human aortas: Continuum and computational modeling with application to arterial clamping.

    PubMed

    Fereidoonnezhad, B; Naghdabadi, R; Holzapfel, G A

    2016-08-01

    Inelastic phenomena such as stress softening and unrecoverable inelastic deformations induced by supra-physiological loading have been observed experimentally in soft tissues such as arteries. These phenomena need to be accounted for in constitutive models of arterial tissues so that computational models can properly predict the outcome of interventional procedures such as arterial clamping and balloon angioplasty that involve non-physiological tissue loading. Motivated by experimental data, a novel pseudo-elastic damage model is proposed to describe discontinuous softening and permanent deformation in arterial tissues. The model is fitted to experimental data and specific material parameters for 9 abdominal and 14 thoracic aortas are provided. Furthermore, the model was implemented in a finite element code and numerically analyzed with respect to experimental tests, i.e. cyclic uniaxial tension in circumferential and longitudinal directions. Results showed that the model is able to capture specific features including anisotropy, nonlinearity, and damage-induced inelastic phenomena, i.e. stress softening and permanent deformation. Finite element results of a more complex boundary-value problem, i.e. aortic clamping considering the three aortic layers, residual stress, non-symmetric blood pressure after clamping, and patient-specific data are also presented. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Mechanical properties of a lap joint under uniform clamping pressure

    NASA Technical Reports Server (NTRS)

    Diller, S. V.; Metherell, A. F.

    1969-01-01

    Equations were derived for the load deflection relations, the energy dissipation per cycle, and the instantaneous rate of dissipation for a lap joint idealized as two overlapping plates clamped together under a uniform clamping pressure.

  17. Bovine aortic arch with supravalvular aortic stenosis.

    PubMed

    Idhrees, Mohammed; Cherian, Vijay Thomas; Menon, Sabarinath; Mathew, Thomas; Dharan, Baiju S; Jayakumar, K

    2016-09-01

    A 5-year-old boy was diagnosed to have supravalvular aortic stenosis (SVAS). On evaluation of CT angiogram, there was associated bovine aortic arch (BAA). Association of BAA with SVAS has not been previously reported in literature, and to best of our knowledge, this is the first case report of SVAS with BAA. Recent studies show BAA as a marker for aortopathy. SVAS is also an arteriopathy. In light of this, SVAS can also possibly be a manifestation of aortopathy associated with BAA.

  18. Clamp on ultrasonic instruments in subsea applications

    SciTech Connect

    Haugen, S.; Hodgson, S.; Upchurch, J.; McMahan, J.; Hazelrigg, K.; Mundorff, J.

    1995-12-01

    Monitoring of solids flow in pipelines has until recently required pipework intervention in order to insert probes and switches. Both sand particles and cleaning pigs are by nature destructive to these directly exposed detectors due to erosion and inertia. The instruments presented in this paper provide a superior alternative in ultrasonic clamp-on technology requiring only superficial pipework installation. Wells can now be operated efficiently in a way that minimizes the risk of erosion and collapse. Pigging operations can be monitored both by on-line pig detection and debris monitoring thereby allowing a safe and optimized survey to take place. The non-intrusive clamp-on concept raises standards in instrument reliability, durability and measurement performance.

  19. Towards a Dynamic Clamp for Neurochemical Modalities

    PubMed Central

    Rivera, Catalina Maria; Kwon, Hyuck-Jin; Hashmi, Ali; Yu, Gan; Zhao, Jiheng; Gao, Jianlong; Xu, Jie; Xue, Wei; Dimitrov, Alexander G.

    2015-01-01

    The classic dynamic clamp technique uses a real-time electrical interface between living cells and neural simulations in order to investigate hypotheses about neural function and structure. One of the acknowledged drawbacks of that technique is the limited control of the cells' chemical microenvironment. In this manuscript, we use a novel combination of nanosensor and microfluidic technology and microfluidic and neural simulations to add sensing and control of chemical concentrations to the dynamic clamp technique. Specifically, we use a microfluidic lab-on-a-chip to generate distinct chemical concentration gradients (ions or neuromodulators), to register the concentrations with embedded nanosensors and use the processed signals as an input to simulations of a neural cell. The ultimate goal of this project is to close the loop and provide sensor signals to the microfluidic lab-on-a-chip to mimic the interaction of the simulated cell with other cells in its chemical environment. PMID:25946635

  20. Mechanical and metallurgical properties of carotid artery clamps.

    PubMed

    Dujovny, M; Kossovsky, N; Kossowsky, R; Segal, R; Diaz, F G; Kaufman, H; Perlin, A; Cook, E E

    1985-11-01

    The mechanical and metallurgical properties of carotid artery clamps were evaluated. The pressure plate retreat propensity, metallurgical composition, surface morphology, magnetic properties, and corrosion resistance of the Crutchfield, Selverstone, Salibi, and Kindt clamps were tested. None of the clamps showed evidence of pressure plate retreat. The clamps differed significantly in their composition, surface cleanliness, magnetic properties, and corrosion resistance. The Crutchfield clamp was the only one manufactured from an ASTM-ANSI-approved implantable stainless steel (AISI 316) and the only clamp in which the surfaces were clean and free of debris. The Selverstone clamp was made principally from AISI 304 stainless steel, as was one Salibi clamp. The pressure plate on another Salibi clamp was made from a 1% chromium and 1% manganese steel. Machining and surface debris consisting principally of aluminum, silicon, and sulfur was abundant on the Selverstone and Salibi clamps. The Kindt clamp was manufactured from AISI 301 stainless steel with a silicate-aluminized outer coating. The Crutchfield and Selverstone clamps were essentially nonferromagnetic, whereas the Salibi and Kindt clamps were sensitive to magnetic flux. In the pitting potential corrosion test, the Crutchfield clamp demonstrated good corrosion resistance with a pitting potential of 310 mV and no surface corrosion or pitting by scanning electron microscopy examination. The Selverstone clamp had lower pitting potentials and showed various degrees of corrosion and surface pitting by scanning electron microscopy. The Salibi pressure plate had a very low pitting potential of -525 mV and showed severe corrosion. By metallurgical criteria, only the Crutchfield clamp is suitable for long term implantation.

  1. Primary Stenting in Infrarenal Aortic Occlusive Disease

    SciTech Connect

    Nyman, Ulf; Uher, Petr; Lindh, Mats; Lindblad, Bengt; Ivancev, Krasnodar

    2000-03-15

    Purpose: To evaluate the results of primary stenting in aortic occlusive disease.Methods: Thirty patients underwent primary stenting of focal concentric (n = 2) and complex aortic stenoses (n = 19), and aortic or aorto-iliac occlusions (n = 9). Sixteen patients underwent endovascular outflow procedures, three of whom also had distal open surgical reconstructions. Median follow-up was 16 months (range 1-60 months).Results: Guidewire crossing of two aorto-biiliac occlusions failed, resulting in a 93% (28/30) technical success. Major complications included one access hematoma, one myocardial infarction, one death (recurrent thromboembolism) in a patient with widespread malignancy, and one fatal hemorrhage during thrombolysis of distal emboli from a recanalized occluded iliac artery. One patient did not improve his symptoms, resulting in a 1-month clinical success of 83% (25/30). Following restenting the 26 stented survivors changed their clinical limb status to +3 (n = 17) and +2 (n = 9). During follow-up one symptomatic aortic restenosis occurred and was successfully restented.Conclusions: Primary stenting of complex aortic stenoses and short occlusions is an attractive alternative to conventional surgery. Larger studies with longer follow-up and stratification of lesion morphology are warranted to define its role relative to balloon angioplasty. Stenting of aorto-biiliac occlusions is feasible but its role relative to bypass grafting remains to be defined.

  2. Caffeine increases aortic stiffness in hypertensive patients.

    PubMed

    Vlachopoulos, Charalambos; Hirata, Kozo; Stefanadis, Christodoulos; Toutouzas, Pavlos; O'Rourke, Michael F

    2003-01-01

    Caffeine is the most widely used pharmacologic substance. Aortic stiffness is an important factor for cardiovascular system performance and a prognosticator of cardiovascular risk. We investigated the effect of caffeine on aortic stiffness in treated hypertensive patients. We studied the effect of caffeine (250 mg) in 12 treated hypertensive patients according to a randomized, placebo-controlled, double-blind, cross-over design during a 3-h period. Aortic stiffness was evaluated by carotid-femoral pulse wave velocity. Systolic blood pressure (BP) and pulse pressure increased significantly throughout the study (by 12.3 and 7.4 mm Hg, P =.005 and P <.01, respectively), whereas diastolic BP did not change. Pulse wave velocity increased (by 0.57 m/sec, P <.05) denoting an increase in aortic stiffness. This effect of caffeine lasted throughout the study (3 h), peaking at 60 min and decreasing progressively thereafter. These results demonstrate, for the first time, that caffeine exerts an acute unfavorable effect on aortic stiffness in treated hypertensive patients. This finding has important implications for the impact of caffeine consumption on cardiovascular risk in hypertension.

  3. Laparoscopy-assisted abdominal aortic aneurysm repair: early and middle-term results of a consecutive series of 122 cases.

    PubMed

    Ferrari, Mauro; Adami, Daniele; Del Corso, Andrea; Berchiolli, Raffaella; Pietrabissa, Andrea; Romagnani, Francesco; Mosca, Franco

    2006-04-01

    Endoaneurysmorrhaphy with intraluminal graft placement, described by Creech, is the gold standard for abdominal aortic aneurysm (AAA) repair. Endovascular aneurysm repair has gained popularity for its minimal invasiveness and satisfying short-term results, but there are still many concerns about the long-term success of the procedure. Since 1998, laparoscopic surgery has been proposed for AAA treatment. The potential benefits of a minimally invasive procedure reproducing the endoaneurysmorrhaphy results over time have been advocated. In our experience, hand-assisted laparoscopic surgery (HALS) has been routinely used for the open-surgery transperitoneal/retroperitoneal approach and for endovascular aneurysm repair. After 4 years, we are able to define the early and middle-term results of such laparoscopic-assisted treatment. From October 2000 to March 2004, 604 consecutive nonurgent AAAs were treated at our institution. Of these, 122 (20.2%) were treated by HALS. Exclusion criteria for HALS were hostile abdomen (previous major abdominal or aortic surgery), bilateral diffuse common iliac and/or hypogastric aneurysms, massive aortoiliac calcifications, and severe cardiac (ejection fraction <35%) and respiratory (P(O2) <60 mm Hg or carbon dioxide >50 mm Hg) insufficiency. Juxtarenal and proximal iliac aneurysms were not a contraindication, nor was obesity. In all patients, we performed a minilaparotomy (7-8 cm) both for laparoscopic hand-assisted dissection and for endoaneurysmorrhaphy. All perioperative data were prospectively recorded. Follow-up consisted of ultrasonography and clinical evaluation after 6 and 12 months and then every year after surgery. The mean laparoscopic and total operative times were respectively 64 +/- 32 minutes and 257 +/- 70 minutes, the mean aortic cross-clamping time was 76 +/- 26 minutes, and the mean autotransfused blood volume was 1136 +/- 711 mL. The overall mortality and morbidity were respectively 0% and 12.2%. Morbidity was surgery

  4. π-Clamp-mediated cysteine conjugation

    NASA Astrophysics Data System (ADS)

    Zhang, Chi; Welborn, Matthew; Zhu, Tianyu; Yang, Nicole J.; Santos, Michael S.; van Voorhis, Troy; Pentelute, Bradley L.

    2016-02-01

    Site-selective functionalization of complex molecules is one of the most significant challenges in chemistry. Typically, protecting groups or catalysts must be used to enable the selective modification of one site among many that are similarly reactive, and general strategies that selectively tune the local chemical environment around a target site are rare. Here, we show a four-amino-acid sequence (Phe-Cys-Pro-Phe), which we call the ‘π-clamp’, that tunes the reactivity of its cysteine thiol for site-selective conjugation with perfluoroaromatic reagents. We use the π-clamp to selectively modify one cysteine site in proteins containing multiple endogenous cysteine residues. These examples include antibodies and cysteine-based enzymes that would be difficult to modify selectively using standard cysteine-based methods. Antibodies modified using the π-clamp retained binding affinity to their targets, enabling the synthesis of site-specific antibody-drug conjugates for selective killing of HER2-positive breast cancer cells. The π-clamp is an unexpected approach to mediate site-selective chemistry and provides new avenues to modify biomolecules for research and therapeutics.

  5. Temperature-Controlled Clamping and Releasing Mechanism

    NASA Technical Reports Server (NTRS)

    Rosing, David; Ford, Virginia

    2005-01-01

    A report describes the development of a mechanism that automatically clamps upon warming and releases upon cooling between temperature limits of approx. =180 K and approx. =293 K. The mechanism satisfied a need specific to a program that involved repeated excursions of a spectrometer between a room-temperature atmospheric environment and a cryogenic vacuum testing environment. The mechanism was also to be utilized in the intended application of the spectrometer, in which the spectrometer would be clamped for protection during launch of a spacecraft and released in the cold of outer space to allow it to assume its nominal configuration for scientific observations. The mechanism is passive in the sense that its operation does not depend on a control system and does not require any power other than that incidental to heating and cooling. The clamping and releasing action is effected by bolt-preloaded stacks of shape-memory-alloy (SMA) cylinders. In designing this mechanism, as in designing other, similar SMA mechanisms, it was necessary to account for the complex interplay among thermal expansion, elastic and inelastic deformation under load, and SMA thermomechanical properties.

  6. Carbon nanotube-clamped metal atomic chain

    PubMed Central

    Tang, Dai-Ming; Yin, Li-Chang; Li, Feng; Liu, Chang; Yu, Wan-Jing; Hou, Peng-Xiang; Wu, Bo; Lee, Young-Hee; Ma, Xiu-Liang; Cheng, Hui-Ming

    2010-01-01

    Metal atomic chain (MAC) is an ultimate one-dimensional structure with unique physical properties, such as quantized conductance, colossal magnetic anisotropy, and quantized magnetoresistance. Therefore, MACs show great potential as possible components of nanoscale electronic and spintronic devices. However, MACs are usually suspended between two macroscale metallic electrodes; hence obvious technical barriers exist in the interconnection and integration of MACs. Here we report a carbon nanotube (CNT)-clamped MAC, where CNTs play the roles of both nanoconnector and electrodes. This nanostructure is prepared by in situ machining a metal-filled CNT, including peeling off carbon shells by spatially and elementally selective electron beam irradiation and further elongating the exposed metal nanorod. The microstructure and formation process of this CNT-clamped MAC are explored by both transmission electron microscopy observations and theoretical simulations. First-principles calculations indicate that strong covalent bonds are formed between the CNT and MAC. The electrical transport property of the CNT-clamped MAC was experimentally measured, and quantized conductance was observed. PMID:20427743

  7. π-Clamp Mediated Cysteine Conjugation

    PubMed Central

    Zhang, Chi; Welborn, Matthew; Zhu, Tianyu; Yang, Nicole J.; Santos, Michael S.; Van Voorhis, Troy; Pentelute, Bradley L.

    2016-01-01

    Site-selective functionalization of complex molecules is a grand challenge in chemistry. Protecting groups or catalysts must be used to selectively modify one site among many that are similarly reactive. General strategies are rare such the local chemical environment around the target site is tuned for selective transformation. Here we show a four amino acid sequence (Phe-Cys-Pro-Phe), which we call the “π-clamp”, tunes the reactivity of its cysteine thiol for the site-selective conjugation with perfluoroaromatic reagents. We used the π-clamp to selectively modify one cysteine site in proteins containing multiple endogenous cysteine residues (e.g. antibodies and cysteine-based enzymes), which was impossible with prior cysteine modification methods. The modified π-clamp antibodies retained binding affinity to their targets, enabling the synthesis of site-specific antibody-drug conjugates (ADCs) for selective killing of HER2-positive breast cancer cells. The π-clamp is an unexpected approach for site-selective chemistry and provides opportunities to modify biomolecules for research and therapeutics. PMID:26791894

  8. Single molecule study of a processivity clamp sliding on DNA

    SciTech Connect

    Laurence, T A; Kwon, Y; Johnson, A; Hollars, C; O?Donnell, M; Camarero, J A; Barsky, D

    2007-07-05

    Using solution based single molecule spectroscopy, we study the motion of the polIII {beta}-subunit DNA sliding clamp ('{beta}-clamp') on DNA. Present in all cellular (and some viral) forms of life, DNA sliding clamps attach to polymerases and allow rapid, processive replication of DNA. In the absence of other proteins, the DNA sliding clamps are thought to 'freely slide' along the DNA; however, the abundance of positively charged residues along the inner surface may create favorable electrostatic contact with the highly negatively charged DNA. We have performed single-molecule measurements on a fluorescently labeled {beta}-clamp loaded onto freely diffusing plasmids annealed with fluorescently labeled primers of up to 90 bases. We find that the diffusion constant for 1D diffusion of the {beta}-clamp on DNA satisfies D {le} 10{sup -14} cm{sup 2}/s, much slower than the frictionless limit of D = 10{sup -10} cm{sup 2}/s. We find that the {beta} clamp remains at the 3-foot end in the presence of E. coli single-stranded binding protein (SSB), which would allow for a sliding clamp to wait for binding of the DNA polymerase. Replacement of SSB with Human RP-A eliminates this interaction; free movement of sliding clamp and poor binding of clamp loader to the junction allows sliding clamp to accumulate on DNA. This result implies that the clamp not only acts as a tether, but also a placeholder.

  9. 33 CFR 183.532 - Clips, straps, and hose clamps.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Clips, straps, and hose clamps... (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Fuel Systems Equipment Standards § 183.532 Clips, straps, and hose clamps. (a) Each clip, strap, and hose clamp must: (1) Be made from a...

  10. 33 CFR 183.532 - Clips, straps, and hose clamps.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Clips, straps, and hose clamps... (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Fuel Systems Equipment Standards § 183.532 Clips, straps, and hose clamps. (a) Each clip, strap, and hose clamp must: (1) Be made from a...

  11. Damping mechanisms of single-clamped and prestressed double-clamped resonant polymer microbeams

    NASA Astrophysics Data System (ADS)

    Schmid, S.; Hierold, C.

    2008-11-01

    In this article, an investigation of the damping mechanisms of resonant single- and double-clamped polymer microbeams for a frequency range from 10 kHz to 5 MHz is presented. The suspended structures are made of SU-8, an epoxy-type photoresist, by means of a sacrificial layer technique. The vibration was measured with a laser-Doppler vibrometer in high vacuum at different temperatures and at atmospheric pressure. The influence of air damping in rarefied air was investigated and the intrinsic damping mechanisms were determined in high vacuum (p <0.05 Pa). After excluding a variety of possible damping factors, the dominant intrinsic dissipation mechanism of the single-clamped microbeams was understood to be the material damping with maximum quality factors (Q) of around 70 at 20 °C. Quality factors of up to 720 at 20 °C were measured for stringlike double-clamped microbeams, which suggest a different intrinsic damping mechanism than material loss. It is shown that internal damping mechanisms due to flexure and elongation have a small impact on the damping of stretched strings. Modeling the clamping loss based on the wave transmission into the suspended anchor plates indicates that it is the dominant intrinsic dissipation in the prestressed double-clamped microresonators. At atmospheric pressure it was shown that at low frequencies the quality factors of single-clamped and stringlike double-clamped microbeams are limited by the squeeze-film air damping. At high frequencies the quality factors are limited by the specific intrinsic damping. In between the two particular regions with a specific dominant damping mechanism the quality factors show a maximum.

  12. Ventricular Septal Defect from Aortic Regurgitation Jet Lesion in Aortic Valve Infective Endocarditis.

    PubMed

    Darabant, Sergiu; Oberton, Shelby B; Roldan, Luis P; Roldan, Carlos A

    2016-03-01

    be determined. Video 1C: Color Doppler two-dimensional TEE view longitudinal to the aortic valve and aortic root, showing a predominantly systolic color Doppler jet originating in the left ventricular outflow tract and/or aorta and crossing the anterior and basal IVS defect into the right ventricle. Videos 1D: These three-dimensional TEE en-face left ventricular outflow tract views of the aortic valve and basal anterior IVS (Video 1D) and medial anterior close up (Video 1E) and lateral en-face (Video 1F) views of the LV outflow tract and IVS clearly define the anterior and basal location of the VSD with irregular borders and a residual mobile tissue fragment. Multiple aortic valve vegetations and a perforation are visible in Video 1D. Videos 1E: These three-dimensional TEE en-face left ventricular outflow tract views of the aortic valve and basal anterior IVS (Video 1D) and medial anterior close up (Video 1E) and lateral en-face (Video 1F) views of the LV outflow tract and IVS clearly define the anterior and basal location of the VSD with irregular borders and a residual mobile tissue fragment. Multiple aortic valve vegetations and a perforation are visible in Video 1D. Videos 1F: These three-dimensional TEE en-face left ventricular outflow tract views of the aortic valve and basal anterior IVS (Video 1D) and medial anterior close up (Video 1E) and lateral en-face (Video 1F) views of the LV outflow tract and IVS clearly define the anterior and basal location of the VSD with irregular borders and a residual mobile tissue fragment. Multiple aortic valve vegetations and a perforation are visible in Video 1D.

  13. The Impact of Deep Versus Moderate Hypothermia on Postoperative Kidney Function After Elective Aortic Hemiarch Repair.

    PubMed

    Arnaoutakis, George J; Vallabhajosyula, Prashanth; Bavaria, Joseph E; Sultan, Ibrahim; Siki, Mary; Naidu, Suveeksha; Milewski, Rita K; Williams, Matthew L; Hargrove, W Clark; Desai, Nimesh D; Szeto, Wilson Y

    2016-10-01

    There remains concern that moderate hypothermic circulatory arrest (MHCA) with antegrade cerebral perfusion (ACP) may provide suboptimal distal organ protection compared with deep hypothermic circulatory arrest (DHCA) with retrograde cerebral perfusion (RCP). We compared postoperative acute kidney injury (AKI) in in patients who underwent elective hemiarch repair with either DHCA/RCP or MHCA/ACP. This was a retrospective review of all patients undergoing elective aortic hemiarch reconstruction for aneurysmal disease between 2009 and 2014. Patients were stratified according to the use of DHCA/RCP versus MHCA/ACP. The primary outcome was the occurrence of AKI at 48 hours, as defined by the Risk, Injury, Failure, Loss, End-Stage (RIFLE ) criteria. A multivariable logistic regression identified risk factors for AKI. One hundred eighteen patients who underwent ACP and 471 patients who underwent RCP were included. The mean lowest temperature was 26.4°C in patients who underwent MHCA/ACP and 17.5°C in patients who underwent DHCA/RCP. Baseline demographics were similar except that patients who underwent DHCA/RCP were more likely to have peripheral arterial disease or bicuspid aortic valves. Cardiopulmonary bypass and aortic cross-clamp times were shorter in the MHCA/ACP group. AKI occurred in 19 (16.2%) patients who underwent MHCA/ACP and 67 (14.3%) patients who underwent DHCA/RCP. Four (0.8%) patients who underwent DHCA/RCP required postoperative dialysis. In-hospital mortality tended to increase with increasing RIFLE classification (RIFLE class-0 (No AKI) = 0.41%; Risk = 1.35%, and Injury = 10.0%; p = 0.09). On multivariable analysis, the lowest temperature and cerebral perfusion strategy were not significant predictors of AKI. Lower baseline glomerular filtration rate (GFR), lower preoperative ejection fraction, and longer cardiopulmonary bypass (CPB) time were independently associated with higher AKI. We applied the sensitive RIFLE criteria to examine AKI in

  14. Aortic root stiffness affects the kinematics of bioprosthetic aortic valves.

    PubMed

    Jahren, Silje Ekroll; Winkler, Bernhard Michael; Heinisch, Paul Philipp; Wirz, Jessica; Carrel, Thierry; Obrist, Dominik

    2017-02-01

    In this study, the influence of aortic root distensibility on the haemodynamic parameters and valve kinematics of a bioprosthetic aortic valve was investigated in a controlled in vitro experiment. An Edwards INTUITY Elite 21 mm sutureless aortic valve (Edwards Lifesciences, Irvine, CA, USA) was inserted in three transparent aortic root phantoms with different wall thicknesses (0.55, 0.85 and 1.50 mm) mimicking different physiological distensibilities. Haemodynamic measurements were performed in an in vitro flow loop at heart rates of 60, 80 and 100 bpm with corresponding cardiac outputs of 3.5, 4.0 and 5.0 l/min and aortic pressures of 100/60, 120/90 and 145/110 mmHg, respectively. Aortic valve kinematics were assessed using a high-speed camera. The geometric orifice area (GOA) was measured by counting pixels in the lumen of the open aortic valve. The effective orifice area (EOA) was calculated from the root-mean-square value of the systolic aortic valve flow rate and the mean systolic trans-valvular pressure gradient. The tested aortic root phantoms reproduce physiological distensibilities of healthy individuals in age groups ranging from 40 to 70 years (±10 years). The haemodynamic results show only minor differences between the aortic root phantoms: the trans-valvular pressure gradient tends to increase for stiffer aortic roots, whereas the systolic aortic valve flow rate remains constant. As a consequence, the EOA decreased slightly for less distensible aortic roots. The GOA and the aortic valve opening and closing velocities increase significantly with reduced distensibility for all haemodynamic measurements. The resulting mean systolic flow velocity in the aortic valve orifice is lower for the stiffer aortic root. Aortic root distensibility may influence GOA and aortic valve kinematics, which affects the mechanical load on the aortic valve cusps. Whether these changes have a significant effect on the onset of structural valve deterioration of bioprosthetic

  15. Technical Aspects of Open Repair for Degenerative Aneurysmal Evolution Despite Early Thoracic Endovascular Repair of Type B Aortic Dissection.

    PubMed

    Aguir, Sonia; El Batti, Salma; Achouh, Paul; Julia, Pierre; Bel, Alain; Fabiani, Jean-Noël; Alsac, Jean-Marc

    2017-04-01

    Closure of the proximal tear by thoracic endovascular aortic repair (TEVAR) at the acute phase appears to be a safe effective treatment to prevent aneurysmal degeneration type B dissection. However, it appears to be inefficient in up to a third of the patient. We report the technical aspects of our experience with patients undergoing secondary open repair after TEVAR for dissecting thoracoabdominal aneurysm despite early closure proximal tear by TEVAR. During a period of 5 years, 96 patients presenting acute type B aortic dissections were treated by TEVAR and followed-up in our institution. Among them, 5 patients experienced an evolution to a dissecting thoracoabdominal aortic aneurysm. Their demographic data and initial medical conditions, delay to reintervention, operative technical details, perioperative and mid-term outcomes were collected and analyzed. All 5 patients (4 male, mean age 58 ± 9) were operated under peripheral normothermic bypass without deep circulatory arrest using the thoracic stent graft as an elephant trunk for completion of the proximal anastomosis. In cases of patency, the false lumen was reapproximated in the anastomosis, 6 visceral arteries were revascularized selectively. One patient died at day 1 of perioperative ventricular fibrillation due to an acute myocardial infarction. The 4 others are alive without complication after a median of 30 months, range (13-22). In our experience, TEVAR was not only efficient at the acute phase to deal with complications, but in cases of subsequent aneurysmal evolution, it made open repair even easier by avoiding very proximal cross-clamping/anastomosis and circulatory arrest. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Greater sympathoadrenal activation with longer preventilation intervals after immediate cord clamping increases hemodynamic lability at birth in preterm lambs.

    PubMed

    Smolich, Joseph J; Kenna, Kelly R; Esler, Murray D; Phillips, Sarah E; Lambert, Gavin W

    2017-06-01

    This study tested the hypothesis that varying degrees of hemodynamic fluctuations seen after birth following immediate cord clamping were related to development of asphyxia with longer cord clamp-to-ventilation intervals, resulting in higher perinatal circulating levels of the catecholamines norepinephrine (NE) and epinephrine (Epi), and thus increased heart rate, blood pressures, and cardiac contractility after birth. Anesthetized preterm fetal lambs were instrumented with 1) aortic (AoT) and pulmonary trunk (PT) micromanometers to obtain pressures and the maximal rate of pressure rise (dP/dtmax) as a surrogate measure of ventricular contractility, and 2) an AoT catheter to obtain samples for blood gas and catecholamine analyses. After delivery, immediate cord clamping was followed by ventilation ∼40 s (n = 7), ∼60 s (n = 8), ∼90 s (n = 9), or ∼120 s later (n = 8), with frequent blood sampling performed before and after ventilation. AoT O2 content fell rapidly after immediate cord clamping (P < 0.001), with an asphyxial state evident at ≥60 s. Plasma NE and Epi levels increased progressively with longer cord clamp-to-ventilation intervals, with an exponential relation between falling AoT O2 content and rising catecholamines (R(2) = 0.64-0.67). Elevated circulating catecholamines persisted for some minutes after ventilation onset, with postbirth surges in heart rate, AoT and PT pressures, and AoT and PT dP/dtmax linearly related to loge of catecholamine levels (R(2) = 0.41-0.54, all P < 0.001). These findings suggest that 1) a greater degree of asphyxia-induced sympathoadrenal activation (reflected in elevated circulating catecholamine levels) occurs with longer intervals between immediate cord clamping and subsequent ventilation, and 2) this activation is a major determinant of hemodynamic fluctuations evident with birth. Copyright © 2017 the American Physiological Society.

  17. Timing of umbilical cord clamping of term infants.

    PubMed

    Ceriani Cernadas, José María

    2017-04-01

    For at least over 200 years, multiple controversies have arisen around the timing of umbilical cord clamping. In the past decades, early cord clamping (within the first 15 seconds) had markedly prevailed. Only in the 21st century, randomized controlled trials have demonstrated the benefits of delayed cord clamping (at 2-3 minutes). Delayed cord clamping has been practiced in obstetrics based on the recommendations made by scientific societies and in systematic reviews, which have provided solid evidence to support this practice in term infants. This review describes the most relevant factors supporting the use of delayed cord clamping in term infants. It points out the essential role played by physiological mechanisms which, undoubtedly, allow us to understand the benefits of delayed cord clamping and advise us to wait for what nature has established. Other relevant aspects supporting delayed cord clamping are also described here. Sociedad Argentina de Pediatría.

  18. Aortic Valve Stenosis

    MedlinePlus

    ... evaluation of aortic stenosis in adults. http://www.uptodate.com/home. Accessed April 29, 2014. Mohty D, ... Valvular heart disease in elderly adults. http://www.uptodate.com/home. Accessed May 2, 2014. Bonow RO, ...

  19. Aortic Aneurysm Statistics

    MedlinePlus

    ... this? Submit What's this? Submit Button Related CDC Web Sites Heart Disease Stroke High Blood Pressure Salt ... to Prevent and Control Chronic Diseases Million Hearts® Web Sites with More Information About Aortic Aneurysm For ...

  20. Aortic Valve Stenosis

    MedlinePlus

    ... pulmonary valve and aortic valve. Each valve has flaps (cusps or leaflets) that open and close once ... valve consists of three tightly fitting, triangular-shaped flaps of tissue called cusps. Some children are born ...

  1. Testing and evaluation of stretching strain in clamped-clamped beams for energy harvesting

    NASA Astrophysics Data System (ADS)

    Emad, Ahmed; Mahmoud, Mohamed A. E.; Ghoneima, Maged; Dessouky, Mohamed

    2016-11-01

    In this paper, evaluation of stretching strain capabilities to harvest energy from a piezoelectric clamped-clamped beam is theoretically modeled and experimentally tested. The utilization of stretching strain has many advantages as: elimination of any substrate material, and the simple electrode configuration. The doubly clamped structure exhibits a highly nonlinear frequency response (Hardening Duffing) that widens the bandwidth during the frequency up-ward sweep. The wide bandwidth makes it suitable for practical applications. A design of 53.5 {{mm}}3 (29.7 {{mm}}3 piezoelectric material + 23.8 {{mm}}3 proof mass) energy harvester was tested using PVDF (polyvinylidene fluoride) that can generate up to 15 μW from vibrations of 0.5{g} at 128 {Hz} and 2 MΩ load. The design can also generate up to 41 μ {{W}} from vibrations of 1{g} at 140 {Hz} and 2 MΩ load.

  2. Whole-GUV patch-clamping.

    PubMed

    Garten, Matthias; Mosgaard, Lars D; Bornschlögl, Thomas; Dieudonné, Stéphane; Bassereau, Patricia; Toombes, Gilman E S

    2017-01-10

    Studying how the membrane modulates ion channel and transporter activity is challenging because cells actively regulate membrane properties, whereas existing in vitro systems have limitations, such as residual solvent and unphysiologically high membrane tension. Cell-sized giant unilamellar vesicles (GUVs) would be ideal for in vitro electrophysiology, but efforts to measure the membrane current of intact GUVs have been unsuccessful. In this work, two challenges for obtaining the "whole-GUV" patch-clamp configuration were identified and resolved. First, unless the patch pipette and GUV pressures are precisely matched in the GUV-attached configuration, breaking the patch membrane also ruptures the GUV. Second, GUVs shrink irreversibly because the membrane/glass adhesion creating the high-resistance seal (>1 GΩ) continuously pulls membrane into the pipette. In contrast, for cell-derived giant plasma membrane vesicles (GPMVs), breaking the patch membrane allows the GPMV contents to passivate the pipette surface, thereby dynamically blocking membrane spreading in the whole-GMPV mode. To mimic this dynamic passivation mechanism, beta-casein was encapsulated into GUVs, yielding a stable, high-resistance, whole-GUV configuration for a range of membrane compositions. Specific membrane capacitance measurements confirmed that the membranes were truly solvent-free and that membrane tension could be controlled over a physiological range. Finally, the potential for ion transport studies was tested using the model ion channel, gramicidin, and voltage-clamp fluorometry measurements were performed with a voltage-dependent fluorophore/quencher pair. Whole-GUV patch-clamping allows ion transport and other voltage-dependent processes to be studied while controlling membrane composition, tension, and shape.

  3. Patch Clamping Protoplasts from Vascular Plants 1

    PubMed Central

    Elzenga, J. Theo M.; Keller, Christopher P.; Van Volkenburgh, Elizabeth

    1991-01-01

    A method is described for the isolation of protoplasts (Pisum sativum, Phaseolus vulgaris, Avena sativa, Arabidopsis thaliana) in preparation for ion flux studies using patch clamp electrophysiology. Protoplasts that have been exposed to hydrolytic, cell wall degrading, enzymes for as little as 5 minutes form gigaseals (seal resistance higher than 10 giga Ohm) with the patch pipette with success rates greater than 40%. Sealing of these protoplasts is fast, averaging less than 2 minutes. This method yields high rates of gigaseal formation in a variety of tissues from both monocots and dicots and will enhance data collection in ion flux studies of plasma membranes of vascular plants. PMID:16668586

  4. The Clamp Loader Assembles the β Clamp onto Either a 3′ or 5′ Primer Terminus

    PubMed Central

    Park, Mee Sook; O'Donnell, Mike

    2009-01-01

    Clamp loaders assemble sliding clamps onto 3′ primed sites for DNA polymerases. Clamp loaders are thought to be specific for a 3′ primed site, and unable to bind a 5′ site. We demonstrate here that the Escherichia coli γ complex clamp loader can load the β clamp onto a 5′ primed site, although with at least 20-fold reduced efficiency relative to loading at a 3′ primed site. Preferential clamp loading at a 3′ site does not appear to be due to DNA binding, as the clamp loader forms an avid complex with β at a 5′ site. Preferential loading at a 3′ versus a 5′ site occurs at the ATP hydrolysis step, needed to close the ring around DNA. We also address DNA structural features that are recognized for preferential loading at a 3′ site. Although the single-stranded template strand extends in opposite directions from 3′ and 5′ primed sites, thus making it a favorite candidate for distinguishing between 3′ and 5′ sites, the single-strand polarity at a primed template junction does not determine 3′ site selection for clamp loading. Instead, we find that clamp loader recognition of a 3′ site lies in the duplex portion of the primed site, not the single-strand portion. We present evidence that the β clamp facilitates its own loading specificity for a 3′ primed site. Implications to eukaryotic clamp loader complexes are proposed. PMID:19759020

  5. Glutaraldehyde-fixed kangaroo aortic wall tissue: histology, crosslink stability and calcification potential.

    PubMed

    Neethling, W M L; Hodge, A J; Glancy, R

    2003-07-15

    Stentless aortic heart valve substitutes, manufactured from biological tissues, are fixed with glutaraldehyde to cross-link collagen, reduce antigenicity, and sterilize the tissue. Despite improved cross linking, reduced antigenicity, and various anticalcification measures, the aortic wall tissue present in these prostheses tends to calcify. The aim of this study was to assess the morphology, collagen cross-link stability, and calcification potential of glutaraldehyde-preserved kangaroo aortic wall tissue as opposed to porcine aortic wall tissue. Porcine and kangaroo aortic wall tissues were fixed in 0.625% buffered glutaraldehyde. Histology and cross-link stability were examined. Calcification potential was determined in the subcutaneous rat model. Kangaroo aortic wall tissue was significantly (p < 0.01) less calcified than porcine aortic wall tissue (26.67 +/- 6.53 versus 41.959 +/- 2.75 microg/mg tissue) at 8 weeks. In conclusion, the histological differences between kangaroo and porcine aortic wall tissue correlate well with the reduced calcification potential of kangaroo aortic wall tissue. The reduced calcification potential could result in improved long-term durability of stentless kangaroo heart valves as bioprostheses. Copyright 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 66B: 356-363, 2003

  6. Minimal access aortic valve replacement using a minimal extracorporeal circulatory system.

    PubMed

    Yilmaz, Alaadin; Rehman, Atiq; Sonker, Uday; Kloppenburg, Geoffrey T L

    2009-03-01

    Minimal access aortic valve replacement (mAVR) has been demonstrated to be beneficial over standard median sternotomy. Similarly, minimal extracorporeal circulation (MECC) has been shown to have less deleterious effects than conventional cardiopulmonary bypass. We report a previously undescribed technique for AVR in combination with MECC by minimal access. We prospectively collected data including one-month postoperative follow-up of the first 50 patients who underwent mAVR utilizing MECC. A temporary Cordis Ventricor (Cordis Corp, Miami, FL) ventricular pacemaker and external defibrillation pads were placed at induction. A J-shaped partial upper sternotomy ending in the third intercostal space was performed. Cannulation was performed in the groin using the Seldinger technique. A vent was introduced directly in the pulmonary artery. Warm blood cardioplegia and carbon dioxide field flooding were used. Fifty consecutive patients (24 male) with a mean age of 68 (range, 34 to 89) were operated between May and December 2007. Operating time was 147 +/- 20 minutes, cross-clamp time was 64 +/- 10 minutes, and perfusion time was 84 +/- 17 minutes. There were no conversions to median sternotomy. Only one peroperative blood transfusion was required and postoperative blood loss was 372 +/- 170 cc. Intensive care unit stay was uneventful (average stay 2 days, range 1 to 8). One patient required a permanent pacemaker and other complications included pneumothorax, superficial wound infection, a late transient postoperative neurologic deficit, and excessive postoperative blood loss requiring mediastinal reexploration. Renal failure and major cerebral accidents did not occur. There was a 100% survival at one-month follow-up. We have shown that minimal access aortic valve replacement using minimal extracorporeal circulation is feasible and provides excellent clinical and cosmetic results.

  7. Advantages of Minimal Access Versus Conventional Aortic Valve Replacement in Elderly or Severely Obese Patients.

    PubMed

    Pisano, Calogera; Totaro, Pasquale; Triolo, Oreste Fabio; Argano, Vincenzo

    The aim of our study was to investigate potential clinical advantages of minimal access versus conventional surgical approach in older and severely obese patients undergoing isolated aortic valve replacement (AVR). One hundred thirty-five patients undergoing isolated primary AVR were enrolled. Propensity score matching was used to compare 42 selected patients operated on ministernotomy (MS, group B) with 42 selected patients operated on full sternotomy (FS, group A). After propensity score matching, the two groups were comparable in terms of preoperative characteristics. Cardiopulmonary bypass time was significantly longer in MS group compared with the FS group [median (95% confidence level or CL), 103 (98.7-106.4) vs 94 (83.6-99) minutes, respectively; P = 0.0019]. No significant difference was observed in aortic cross-clamp time [median (95% CL), 73 (71.1-78.2) vs 69.5 (62.7-83) minutes; P = 0.4]. Significantly shorter ventilation time [median (95% CL), 13 (12-16.4) vs 24 (22-25) hours; P = 0.00018], intensive care unit stay [median (95% CL), 1 vs 2 days; P = 0.00017], and hospital stay [median (95% CL), 8.5 (8-10.8) vs 13.5 (11.1-14) days; P = 0.00030] were shown in the MS group. The age subgroup analysis showed that statistical significance for mechanical ventilation, intensive care unit, and hospital stay was specific for patients older than 75 years. The analysis of body mass index quartile showed that statistical significance for mechanical ventilation was specific for patients in the fourth quartile. Minimal access AVR is a reproducible, safe, and effective surgical option in patients candidate for isolated AVR, and our study suggests a faster recovery when used in severely obese or older patients.

  8. Clinical and biochemical outcomes for additive mesenteric and lower body perfusion during hypothermic circulatory arrest for complex total aortic arch replacement surgery.

    PubMed

    Fernandes, P; Cleland, A; Adams, C; Chu, M W A

    2012-11-01

    Surgical repair of transverse aortic arch aneurysms frequently employ hypothermia and antegrade cerebral perfusion as protective strategies during circulatory arrest. However, prolonged mesenteric and lower limb ischemia can lead to significant lactic acidosis and end organ dysfunction, which remains a significant cause of post-operative morbidity and mortality. We report our experience with additive warm mesenteric and lower body perfusion (1-3 L/min, 30°C) in addition to continuous cerebral and myocardial perfusion in 5 patients who underwent total aortic arch replacement with trifurcated head vessel re-implantation and distal elephant trunk reconstruction. Concomitant surgical procedures included re-operations (2), aortic root operations (2), coronary artery bypass (2) and descending thoracic aortic replacement (1). Serum lactate levels demonstrated a rapid decline from a peak 9.9 ± 2.6 post circulatory arrest to 3.4 ± 2.0 in the intensive care unit (ICU). The lowest serum bicarbonate levels were 19.3 ± 3.5 mmol/L, intra-operatively, which normalized to 28.4 ± 2.4 mmol/L on return to the ICU. The lowest pH levels were 7.25 ± 0.10, corrected to 7.43 ± 0.04 on return to the ICU. Mean cardiopulmonary bypass and aortic cross-clamp times were 361 ± 104 and 253 ± 85 minutes, respectively. Mean cerebral and lower body circulatory arrest times were 0 (0) and 50 ± 35 minutes, respectively. The mean time required for systemic rewarming was 95 ± 66 minutes. There were no in-hospital mortalities and no patient experienced any neurological, mesenteric, renal or lower limb ischemic complications. Two patients required mechanical ventilation >24 hours, and one patient returned for reoperation for bleeding. Median intensive care unit and total hospital lengths of stay were 5 and 16 days, respectively. Our results suggest early serum lactate clearance, normalization of acidosis, and metabolic recovery when utilizing a simultaneous cerebral perfusion and warm body

  9. [Left Ventricular Rupture during Both Mitral and Aortic Valve Replacements].

    PubMed

    Kurumisawa, Soki; Aizawa, Kei; Takazawa, Ippei; Sato, Hirotaka; Muraoka, Arata; Ohki, Shinnichi; Saito, Tsutomu; Kawahito, Koji; Misawa, Yoshio

    2015-05-01

    A 73-year-old woman on hemodialysis was transferred to our hospital for surgical treatment of heart valve disease. She required both mitral and aortic valve replacement with mechanical valves, associated with tricuspid annuloplasty. After aortic de-clamping, a massive hemorrhage from the posterior atrioventricular groove was observed. Under repeated cardiac arrest, the left atrium was reopened, the implanted mitral prosthetic valve was removed and a type I left ventricular rupture (Treasure classification) was diagnosed. The lesion was directly repaired with mattress stitches and running sutures, using reinforcement materials such as a glutaraldehyde-treated bovine pericardium. To avoid mechanical stress by the prosthetic valve on the repaired site, a mechanical valve was implanted using a translocation method. The patient suffered from aspiration pneumonia and disuse atrophy for 3 months. However, she was doing well at 1 year post-operation.

  10. Are Aortic Stent Grafts Safe in Pregnancy?

    PubMed Central

    Khandanpour, Nader; Mehta, Tapan A.; Adiseshiah, M.; Meyer, Felicity J.

    2015-01-01

    Aortic stent grafts are increasingly used to treat aortic aneurysms and also other aortic pathologies. The safety of aortic stent grafts in pregnancy has never been studied or reported. We report on two cases of aortic stent grafts in pregnant women and discuss the effect of pregnancy on these aortic stent grafts. PMID:26229702

  11. Aortic involvement in relapsing polychondritis.

    PubMed

    Le Besnerais, Maëlle; Arnaud, Laurent; Boutémy, Jonathan; Bienvenu, Boris; Lévesque, Hervé; Amoura, Zahir; Marie, Isabelle

    2017-05-17

    To assess prevalence of aortic involvement in relapsing polychondritis (RP) patients; to evaluate clinical features and long-term outcome of RP patients exhibiting aortitis, aortic ectasia and/or aneurysm. One hundred and seventy-two RP patients underwent aortic computed tomography (CT)-scan; they were seen in 3 medical centers. Eleven patients (6.4%) had aortic involvement, occurring within a median time of 2 years after RP diagnosis. CT-scan showed isolated aortitis (n=2); the 9 other patients exhibited: aortitis and aortic aneurysm (n=2) or ectasia (n=1), isolated aortic aneurysm (n=4) or ectasia (n=2); aortic localizations were as follows: thoracic (n=6), abdominal (n=2), thoracic and abdominal (n=4) aorta. Patients exhibited: resolution (n=3) improvement (n=3), stabilization (n=4) or deterioration (n=1) of aortic localization. Five patients experienced recurrence of aortic localization; one patient died of aortic abdominal aneurysm rupture. Predictive factors of death related to aortic complications were: aortitis on CT-scan, higher median levels of erythrocyte sedimentation rate. Predictive parameters of aortic relapses were: aortitis on CT-scan and involvement of the abdominal aorta. This study underlines that aortic involvement is severe in RP. Furthermore, we suggest that RP patients exhibiting poor prognostic factors, including panaortitis and higher values of ESR, may require more aggressive therapy. Copyright © 2017 Société française de rhumatologie. Published by Elsevier SAS. All rights reserved.

  12. Laser-assisted patch clamping: a methodology

    NASA Technical Reports Server (NTRS)

    Henriksen, G. H.; Assmann, S. M.; Evans, M. L. (Principal Investigator)

    1997-01-01

    Laser microsurgery can be used to perform both cell biological manipulations, such as targeted cell ablation, and molecular genetic manipulations, such as genetic transformation and chromosome dissection. In this report, we describe a laser microsurgical method that can be used either to ablate single cells or to ablate a small area (1-3 microns diameter) of the extracellular matrix. In plants and microorganisms, the extracellular matrix consists of the cell wall. While conventional patch clamping of these cells, as well as of many animal cells, requires enzymatic digestion of the extracellular matrix, we illustrate that laser microsurgery of a portion of the wall enables patch clamp access to the plasma membrane of higher plant cells remaining situated in their tissue environment. What follows is a detailed description of the construction and use of an economical laser microsurgery system, including procedures for single cell and targeted cell wall ablation. This methodology will be of interest to scientists wishing to perform cellular or subcellular ablation with a high degree of accuracy, or wishing to study how the extracellular matrix affects ion channel function.

  13. Laser-assisted patch clamping: a methodology

    NASA Technical Reports Server (NTRS)

    Henriksen, G. H.; Assmann, S. M.; Evans, M. L. (Principal Investigator)

    1997-01-01

    Laser microsurgery can be used to perform both cell biological manipulations, such as targeted cell ablation, and molecular genetic manipulations, such as genetic transformation and chromosome dissection. In this report, we describe a laser microsurgical method that can be used either to ablate single cells or to ablate a small area (1-3 microns diameter) of the extracellular matrix. In plants and microorganisms, the extracellular matrix consists of the cell wall. While conventional patch clamping of these cells, as well as of many animal cells, requires enzymatic digestion of the extracellular matrix, we illustrate that laser microsurgery of a portion of the wall enables patch clamp access to the plasma membrane of higher plant cells remaining situated in their tissue environment. What follows is a detailed description of the construction and use of an economical laser microsurgery system, including procedures for single cell and targeted cell wall ablation. This methodology will be of interest to scientists wishing to perform cellular or subcellular ablation with a high degree of accuracy, or wishing to study how the extracellular matrix affects ion channel function.

  14. Successful transfemoral aortic valve implantation through aortic stent graft after endovascular repair of abdominal aortic aneurysm.

    PubMed

    Kawashima, Hideyuki; Watanabe, Yusuke; Kozuma, Ken

    2017-04-01

    The patient was a 91-year-old woman presenting with severe aortic valve stenosis. Pre-procedural computed tomography scan revealed a 45-mm abdominal aortic aneurysm (AAA). Transfemoral transcatheter aortic valve implantation (TF-TAVI) was performed after endovascular aortic repair (EVAR) of the AAA. The 23-mm Edwards Sapien XT system passed through the aortic stent graft smoothly. This is the first case report showing that successful TF-TAVI can be performed through a prior abdominal aortic stent graft. TF-TAVI after EVAR of AAA is a feasible option for patients with extremely poor access.

  15. Aortic aneurysm repair - endovascular- discharge

    MedlinePlus

    ... MRI scan Aortic aneurysm repair - endovascular Aortic angiography Hardening of ... Center-Shreveport, Shreveport, LA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla ...

  16. The protective effect of melatonin on remote organ liver ischemia and reperfusion injury following aortic clamping.

    PubMed

    Ozsoy, Mustafa; Gonul, Yucel; Ozkececi, Ziya Taner; Bali, Ahmet; Celep, Ruchan Bahadir; Koçak, Ahmet; Adali, Fahri; Tosun, Murat; Celik, Sefa

    2016-01-01

    Dopo il ripristino della circolazione sanguigna e dell’ossigenazione possono verificarsi gravi danni locali e sistemici ai tessuti temporaneamente ischemici, noti come danni da riperfusione. Lo scopo di questo studio è stato quello di indagare sui possibili effetti protettivi della melatonina nei confronti dei danni sistemici da riperfuzione nel tessuto epatico a seguito dell’occlusione dell’aorta sottorenale. Per questo studio sono stati impiegati un totale di 21 ratti Wistar-albini di sesso maschile, suddivisi in tre gruppi: I gruppo – laparotomia e contemporanea dissezione dell’aorta infrarenale; II gruppo – somministrazione intraperitoneale di circa 1 ml di fisiologica al 0,9% di NaCl 30’ prima e dopo l’operazione di occlusione. Dopo la laparotomia e sua dissezione, l’aorta sottorenale è clampata per 30’ e quindi riabitata al circolo di riperfusione per 2 ore; III gruppo – 30’ prima del clampaggio dell’aorta sottorenale è stata somministrata la malatonina, seguita dal clampaggio aortico per 30’ e un periodo di riperfusione di 2 ore. Sono stati quindi dosati i tassi sierici di aspartate aminotransferasi, alanine aminotransferasi, and lattato dehydrogenase, risultati significativamente più elevate nei gruppi II e III rispetto al gruppo I di controllo. Gli esami di laboratorio sono tornati ai livelli normali nel III gruppo dopo il trattamento. Sebbene si sia avuto un decremento del tasso sierico di IL-1β, IL-6, IL-18, TNF-α, e IFN- γ nel gruppo trattato con melatonina, questo decremento ha assunto valore statisticamente significativo per i livelli sierici di IL- 18, TNF-α, e IFN- γ in paragone con quanto osservato nel II gruppo. I tassi sierici dello stato totale di antiossidanti tissutali (TOC) e dell’indice di stress ossidativo dei tessuti (OSI) sono risultati diminuiti e quelli della capacità antiossidante (TAC) risultano accresciuti dalla melatonina. Il risultato di questo studio suggerisce effetti antiossidanti della melatonina ed effetti epatoprotettivi nei confronti dei danni da riperfusione.

  17. [Coronary revascularization with extracorporeal circulation, aortic clamping or OPCAB: does the method's choice influence the results?].

    PubMed

    Coelho, P; Gomes, V; Silva, N D; Fragata, I; Ramos, J S; Fragata, J

    2005-01-01

    Off pump CABG-OPCAB is the most recent development in coronary surgery and is aimed to avoid the complications of extracorporeal circulation and to compete with interventional cardiology. The objective of this study is to compare 3 methods for cardiac support for CABG. Between February 2001 and December 2002 ninety consecutive patients were operated by the same surgeon and the same team with the following techniques: extracorporeal circulation (CEC) and ischaemic arrest, CEC and beating heart, and OPCAB. There were no difference in mortality and morbidity for the 3 groups of patients. The OPCAB group showed less ventilation time, less blood transfusion needs and shorter hospital stays than the other 2 groups of patients that showed no differences between each other. OPCAB is safe and showed slight advantage over CEC supported groups but the number of grafts per patient was smaller.

  18. [Congenital aortic stenosis].

    PubMed

    Yamaguchi, M

    2001-08-01

    Recent advances in and controversies concerning the management of children with congenital valvular aortic stenosis are discussed. In neonates with critical aortic stenosis, improved survival has recently been reported after surgical open valvotomy and balloon valvuloplasty, although it is difficult at this point to compare the results of the two procedures and determine their differential indications. Good results have also been achieved after extended aortic valvuloplasty for recurrent aortic stenosis and/or insufficiency, but the length of follow-up in these patients is still short. The technique first reported in 1991 for bilateral enlargement fo a small annulus permits the insertion of an aortic valve 3-4 sizes larger than the native annulus. It entails no risk of distorting the mitral valve, damaging the conduction system or important branches of the coronary arteries, or resulting in left ventricular dysfunction. The Ross procedure is now widely applied in the West, with reports of early mortality rates of less than 5% and event-free survival rates of 80-90% during follow-up of 4-8 years. Longer follow-up and continued careful evaluation are required to resolve the issue of possible dilatation and subsequent neoaortic valve dysfunction and pulmonary stenosis due to allograft degeneration after pulmonary autograft root replacement in children.

  19. Sutureless Aortic Valve Replacement International Registry (SU-AVR-IR): design and rationale from the International Valvular Surgery Study Group (IVSSG).

    PubMed

    Di Eusanio, Marco; Phan, Kevin; Bouchard, Denis; Carrel, Thierry P; Dapunt, Otto E; Di Bartolomeo, Roberto; Eichstaedt, Harald C; Fischlein, Theodor; Folliguet, Thierry; Gersak, Borut; Glauber, Mattia; Haverich, Axel; Misfeld, Martin; Oberwalder, Peter J; Santarpino, Giuseppe; Shrestha, Malakh Lal; Solinas, Marco; Vola, Marco; Alamanni, Francesco; Albertini, Alberto; Bhatnagar, Gopal; Carrier, Michel; Clark, Stephen; Collart, Federic; Kappert, Utz; Kocher, Alfred; Meuris, Bart; Mignosa, Carmelo; Ouda, Ahmed; Pelletier, Marc; Rahmanian, Parwis Baradaran; Reineke, David; Teoh, Kevin; Troise, Giovanni; Villa, Emmanuel; Wahlers, Thorsten; Yan, Tristan D

    2015-03-01

    Sutureless aortic valve replacement (SU-AVR) is an innovative approach which shortens cardiopulmonary bypass and cross-clamp durations and may facilitate minimally invasive approach. Evidence outlining its safety, efficacy, hemodynamic profile and potential complications is replete with small-volume observational studies and few comparative publications. Minimally invasive aortic valve surgery and high-volume SU-AVR replacement centers were contacted for recruitment into a global collaborative coalition dedicated to sutureless valve research. A Research Steering Committee was formulated to direct research and support the mission of providing registry evidence warranted for SU-AVR. The International Valvular Surgery Study Group (IVSSG) was formed under the auspices of the Research Steering Committee, comprised of 36 expert valvular surgeons from 27 major centers across the globe. IVSSG Sutureless Projects currently proceeding include the Retrospective and Prospective Phases of the SU-AVR International Registry (SU-AVR-IR). The global pooling of data by the IVSSG Sutureless Projects will provide required robust clinical evidence on the safety, efficacy and hemodynamic outcomes of SU-AVR.

  20. Current umbilical cord clamping practices and attitudes of obstetricians and midwives toward delayed cord clamping in Saudi Arabia.

    PubMed

    Ibrahim, Nadia O; Sukkarieh, Hatouf H; Bustami, Rami T; Alshammari, Elaf A; Alasmari, Lama Y; Al-Kadri, Hanan M

    2017-01-01

    In Saudi Arabia, as in many countries, there is usually no clear definition of the timing of umbilical cord clamping (UCC) in the policies and procedures used by hospitals. The World Health Organization (WHO) recommends delayed cord clamping (DCC) ( > 1 minute after birth) as it can significantly improve hemodynamics and long-term neurodevelopment. To investigate current practices of healthcare professionals on the timing of UCC in Saudi Arabia. Cross-sectional survey. Five tertiary hospitals in Riyadh, Saudi Arabia, during May to October 2016. Obstetricians and midwives completed a widely-used questionnaire on UCC practices. Current UCC practices and attitudes of obstetricians and midwives toward DCC. Eighty-two obstetricians and 75 midwives completed the questionnaire for a response rate of 80%. The majority of respondents were aged 30 years or older (81%) and 84% were females. Most respondents were non-Saudi (66%) and had an educational level of bachelor's degree or higher (72%). Only 42% of respondents reported the existence of UCC guidelines in their practice; 38% reported the existence of a set time for UCC when the neonate was term and healthy, and only 32% had a set time for UCC in preterm neonates. While lower levels of agreement were reported among obstetricians and midwives on the benefits of DCC for babies requiring positive pressure ventilation, the majority of respondents (69-71%) thought that DCC was generally good for both term and preterm babies and that its benefits extend beyond the neonatal period. While the majority of obstetricians and midwives that participated in this study had a positive perception toward DCC, this did not translate to their daily practice as most of these professionals reported a lack of existing UCC guidelines in their institutions. Further studies are warranted to confirm these findings. Participant selection by convenience sampling.

  1. Spectral infrared hemispherical reflectance measurements for LDEF tray clamps

    NASA Technical Reports Server (NTRS)

    Cromwell, B. K.; Shepherd, S. D.; Pender, C. W.; Wood, B. E.

    1993-01-01

    Infrared hemispherical reflectance measurements that were made on 58 chromic acid anodized tray clamps from LDEF are described. The measurements were made using a hemiellipsoidal mirror reflectometer with interferometer for wavelengths between 2-15 microns. The tray clamps investigated were from locations about the entire spacecraft and provided the opportunity for comparing the effects of atomic oxygen at each location. Results indicate there was essentially no dependence on atomic oxygen fluence for the surfaces studied, but there did appear to be a slight dependence on solar radiation exposure. The reflectances of the front sides of the tray clamps consistently were slightly higher than for the protected rear tray clamp surfaces.

  2. An Optimal Cell Detection Technique for Automated Patch Clamping

    NASA Technical Reports Server (NTRS)

    McDowell, Mark; Gray, Elizabeth

    2004-01-01

    While there are several hardware techniques for the automated patch clamping of cells that describe the equipment apparatus used for patch clamping, very few explain the science behind the actual technique of locating the ideal cell for a patch clamping procedure. We present a machine vision approach to patch clamping cell selection by developing an intelligent algorithm technique that gives the user the ability to determine the good cell to patch clamp in an image within one second. This technique will aid the user in determining the best candidates for patch clamping and will ultimately save time, increase efficiency and reduce cost. The ultimate goal is to combine intelligent processing with instrumentation and controls in order to produce a complete turnkey automated patch clamping system capable of accurately and reliably patch clamping cells with a minimum amount of human intervention. We present a unique technique that identifies good patch clamping cell candidates based on feature metrics of a cell's (x, y) position, major axis length, minor axis length, area, elongation, roundness, smoothness, angle of orientation, thinness and whether or not the cell is only particularly in the field of view. A patent is pending for this research.

  3. Delayed cord clamping and cord gas analysis at birth.

    PubMed

    Xodo, Serena; Xodo, Luigi; Berghella, Vincenzo

    2017-09-16

    Delayed cord clamping for at least 60 seconds in both term and preterm babies is a major recent change in clinical care. Delayed cord clamping has several effects on other possible interventions. One of these is the effect of delayed cord clamping on umbilical artery gas analysis. When indicated, umbilical artery gas analysis can safely be done either with early cord clamping, or, probably most of the times it is necessary, during delayed cord clamping with the cord still unclamped. Paired blood samples (one from the umbilical artery and one from the umbilical vein) can be taken from the pulsating and unclamped cord, immediately after birth, during delayed cord clamping, without any effect on either the accuracy of umbilical artery gas analysis or on the transfusion of blood through delayed cord clamping. Umbilical artery gas analysis should instead not be done after delayed cord clamping, since delayed cord clamping alters several acid-based parameters and lactate values. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  4. Obstetricians' attitudes and beliefs regarding umbilical cord clamping.

    PubMed

    Jelin, Angie C; Kuppermann, Miriam; Erickson, Kristine; Clyman, Ronald; Schulkin, Jay

    2014-09-01

    Although delayed umbilical cord clamping has been demonstrated to reduce the incidence of intraventricular hemorrhage and neonatal sepsis, and decrease the need for neonatal transfusions (without affecting cord pH, Apgar scores or the need for phototherapy), the extent to which this practice is being employed is unknown. We conducted a survey of US obstetricians to assess their attitudes and beliefs about cord clamping. Questionnaires were randomly mailed to members of the American College of Obstetricians and Gynecologists (ACOG), and the Collaborative Ambulatory Research Network (CARN). The data were analyzed using Chi-square and Student t tests. The response rates for the CARN and other ACOG members were 47% and 21%, respectively. Most (88%) responders reported their hospital had no umbilical cord clamping policy. The most frequent response for optimal timing of umbilical cord clamping, regardless of gestational age, was "don't know". Potential for neonatal red blood cell transfusion was the only concern cited as a reason for being somewhat or very inclined to delay umbilical cord clamping (51%). Delayed neonatal resuscitation (76%) was listed as a reason to clamp the cord immediately, despite the paucity of literature to support immediate cord clamping in this cohort. Despite substantial evidence supporting the practice of delayed cord clamping, few institutions have policies regarding this practice. Moreover, obstetricians' beliefs about the appropriate timing for umbilical cord clamping are not consistent with the evidence that demonstrates its beneficial impact on neonatal outcomes.

  5. Robotic aortic surgery.

    PubMed

    Duran, Cassidy; Kashef, Elika; El-Sayed, Hosam F; Bismuth, Jean

    2011-01-01

    Surgical robotics was first utilized to facilitate neurosurgical biopsies in 1985, and it has since found application in orthopedics, urology, gynecology, and cardiothoracic, general, and vascular surgery. Surgical assistance systems provide intelligent, versatile tools that augment the physician's ability to treat patients by eliminating hand tremor and enabling dexterous operation inside the patient's body. Surgical robotics systems have enabled surgeons to treat otherwise untreatable conditions while also reducing morbidity and error rates, shortening operative times, reducing radiation exposure, and improving overall workflow. These capabilities have begun to be realized in two important realms of aortic vascular surgery, namely, flexible robotics for exclusion of complex aortic aneurysms using branched endografts, and robot-assisted laparoscopic aortic surgery for occlusive and aneurysmal disease.

  6. Aortic hammer syndrome.

    PubMed

    Komen, Niels; Vercauteren, Sven; de Roover, Dominique

    2011-08-01

    To present a case of penetrating aortic ulcer with extraordinary etiology. A 57-year-old man was admitted with acute retrosternal and interscapular pain. He was a demolition worker and often used a pneumatic drill to which he pressed his chest as he drilled. Clinical examination showed previously undiagnosed hypertension. Computed tomographic angiography disclosed a penetrating aortic ulcer in the descending thoracic aorta without any sign of atherosclerosis. Initial treatment consisted of blood pressure control. However, due to progression of the lesion, endovascular treatment was performed to implant a covered endoprosthesis. We hypothesize that the etiology of the ulcer was the shear forces developed by incorrect, repetitive use of the pneumatic hammer in combination with the untreated hypertension. This is analogous to the hypothenar hammer syndrome, and we propose naming this the "aortic hammer syndrome."

  7. [Inflammatory abdominal aortic aneurysm].

    PubMed

    Mikami, Y; Kyogoku, M

    1994-08-01

    Inflammatory abdominal aortic aneurysm (IAAA) is a distinct clinicopathological entity, characterized by: (1) clinical presentation, such as back pain, weight loss, and increased ESR, (2) patchy and/or diffuse lymphoplasmacytic infiltration, and (3) marked periaortic fibrosis resulting in thickening of the aneurysmal wall and occasional retroperitoneal fibrosis. Its pathogenesis is unknown, but some authors support the theory that IAAA is a subtype of atherosclerotic abdominal aortic aneurysm because of close relationship between IAAA and atherosclerotic change. In this article, we describe clinical and histological features of IAAA on the basis of the literature and our review of 6 cases of IAAA, emphasizing the similarity and difference between IAAA and atherosclerotic abdominal aortic aneurysm. Our review supports that marked lamellar fibrosis completely replacing the media and adventitia, patchy lymphocytic infiltration (mostly B cells) and endarteritis obliterans are characteristic features of IAAA.

  8. Thermal stiffening of clamped elastic ribbons

    NASA Astrophysics Data System (ADS)

    Wan, Duanduan; Nelson, David R.; Bowick, Mark J.

    2017-07-01

    We use molecular dynamics to study the vibrations of a thermally fluctuating two-dimensional elastic membrane clamped at both ends. We directly extract the eigenmodes from resonant peaks in the frequency domain of the time-dependent height and measure the dependence of the corresponding eigenfrequencies on the microscopic bending rigidity of the membrane, taking care also of the subtle role of thermal contraction in generating a tension when the projected area is fixed. At finite temperatures we show that the effective (macroscopic) bending rigidity tends to a constant as the bare bending rigidity vanishes, consistent with theoretical arguments that the large-scale bending rigidity of the membrane arises from a strong thermal renormalization of the microscopic bending rigidity. Experimental realizations include covalently bonded two-dimensional atomically thin membranes such as graphene and molybdenum disulfide or soft matter systems such as the spectrin skeleton of red blood cells or diblock copolymers.

  9. Nanoindentation characteristics of clamped freestanding Cu membranes.

    PubMed

    Wang, Tong Hong; Fang, Te-Hua; Kang, Shao-Hui; Lin, Yu-Cheng

    2007-04-04

    This research employed instrumented nanoindentation to address the issue of bending to stretching-induced deformation of clamped freestanding Cu membranes. The experimental results show that indentation-induced plastic deformation only comes into effect at the centre and the indented edge of the Cu membrane when the indenter is applied, while the other locations remain undamaged. A step-by-step evolution was presumed for the time histories of the bending to stretching-induced deformation and for the timing of the significant change in slope of the load-deflection curve. Deformation was deliberately introduced at the transition from the single-point bending indentation to the surface stretching indentation at the impact location touched with the indenter. Good elastic recovery was found at locations away from the indenter. A similar finding can be arrived at by means of finite element analysis.

  10. Pipe lifting hook having clamp assembly

    SciTech Connect

    Codner, J.A.

    1984-06-12

    A pipe lifting hook is provided having a generally ''C'' shaped hook member having an elongated lower portion being insertable within the end of a joint of pipe and having an upper portion positionable above the pipe and provided with lifting connection means. The hook member is frictionally clamped to the pipe by grip shoe means that is movably supported by the upper portion of the hook member and is selectably movable from a released position out of contact with said pipe to a locked position in frictional locking engagement with the outer surface of the pipe. A ratchet mechanism couples said grip shoe means to the upper portion of the hook member and is manually positionable to lock said grip shoe means at said locked position or release said grip shoe means for movement toward said released position thereof.

  11. Chronic Type A Aortic Dissection and Giant Aortic Root Aneurysm After Aortic Valve Replacement

    PubMed Central

    Puga, Andrés Enríquez; Rodríguez, Sara Castaño; Pañero, Blanca Mateos; Moreira, Beatriz Castaño; López Almodóvar, Luis Fernando

    2016-01-01

    We describe the case of a 61-year-old male with a giant aortic root aneurysm associated with chronic aortic Type A dissection. The patient had been operated on 16 years before due to aortic annuloectasia with mechanical valve replacement. The patient underwent revision aortic surgery with a Bentall-De Bono operation with Svensson modification, using a #21 On-X Valsalva mechanical valve conduit. The postoperative course was uneventful. PMID:28097190

  12. The PCNA-RFC families of DNA clamps and clamp loaders.

    PubMed

    Majka, Jerzy; Burgers, Peter M J

    2004-01-01

    The proliferating cell nuclear antigen PCNA functions at multiple levels in directing DNA metabolic pathways. Unbound to DNA, PCNA promotes localization of replication factors with a consensus PCNA-binding domain to replication factories. When bound to DNA, PCNA organizes various proteins involved in DNA replication, DNA repair, DNA modification, and chromatin modeling. Its modification by ubiquitin directs the cellular response to DNA damage. The ring-like PCNA homotrimer encircles double-stranded DNA and slides spontaneously across it. Loading of PCNA onto DNA at template-primer junctions is performed in an ATP-dependent process by replication factor C (RFC), a heteropentameric AAA+ protein complex consisting of the Rfc1, Rfc2, Rfc3, Rfc4, and Rfc5 subunits. Loading of yeast PCNA (POL30) is mechanistically distinct from analogous processes in E. coli (beta subunit by the gamma complex) and bacteriophage T4 (gp45 by gp44/62). Multiple stepwise ATP-binding events to RFC are required to load PCNA onto primed DNA. This stepwise mechanism should permit editing of this process at individual steps and allow for divergence of the default process into more specialized modes. Indeed, alternative RFC complexes consisting of the small RFC subunits together with an alternative Rfc1-like subunit have been identified. A complex required for the DNA damage checkpoint contains the Rad24 subunit, a complex required for sister chromatid cohesion contains the Ctf18 subunit, and a complex that aids in genome stability contains the Elg1 subunit. Only the RFC-Rad24 complex has a known associated clamp, a heterotrimeric complex consisting of Rad17, Mec3, and Ddc1. The other putative clamp loaders could either act on clamps yet to be identified or act on the two known clamps.

  13. Translocation of the Aortic Arch with Norwood Procedure for Hypoplastic Left Heart Syndrome Variant with Circumflex Retroesophageal Aortic Arch

    PubMed Central

    Lee, Chee-Hoon; Seo, Dong Ju; Bang, Ji Hyun; Goo, Hyun Woo; Park, Jeong-Jun

    2014-01-01

    Retroesophageal aortic arch, in which the aortic arch crosses the midline behind the esophagus to the contralateral side, is a rare form of vascular anomaly. The complete form may cause symptoms by compressing the esophagus or the trachea and need a surgical intervention. We report a rare case of a hypoplastic left heart syndrome variant with the left retroesophageal circumflex aortic arch in which the left aortic arch, retroesophageal circumflex aorta, and the right descending aorta with the aberrant right subclavian artery encircle the esophagus completely, thus causing central bronchial compression. Bilateral pulmonary artery banding and subsequent modified Norwood procedure with extensive mobilization and creation of the neo-aorta were performed. As a result of the successful translocation of the aorta, the airway compression was relieved. The patient underwent the second-stage operation and is doing well currently. PMID:25207249

  14. Inflammatory abdominal aortic aneurysm.

    PubMed

    Savarese, R P; Rosenfeld, J C; DeLaurentis, D A

    1986-05-01

    Between January 1976 and December 1982, 181 patients with abdominal aortic aneurysms were treated surgically, and in 13 patients the aneurysms were found to be inflammatory. Inflammatory aneurysms of the abdominal aorta (IAAA) share important characteristics with typical atherosclerotic abdominal aortic aneurysms. Diagnosis and surgical management of IAAA are distinctive which suggests that IAAA should be considered separately, as a varient of typical abdominal aortic aneurysms. IAAA occur predominantly in males. The presenting symptoms are often idiosyncratic and include severe abdominal or back pain, or both, and ureteral obstruction; the diagnosis of IAAA should be considered when these symptoms are present. Although grossly and microscopically, the perianeurysmal fibrosis resembles idiopathic retroperitoneal fibrosis, the two conditions can be differentiated. At the present time, ultrasonography and computed tomography appear to offer reliable means for diagnosing IAAA. The presence of IAAA, whether established preoperatively or discovered unexpectedly at operation, necessitate certain modifications in the surgical approach, in order to avoid injuring the duodenum and the venous structures. Most patients can be successfully treated by resection and graft replacement. Rupture of the aneurysm in IAAA appears to be less frequent than in typical atherosclerotic abdominal aortic aneurysm.

  15. Combination Space Station Handrail Clamp and Pointing Device

    NASA Technical Reports Server (NTRS)

    Hughes, Stephen J. (Inventor)

    1999-01-01

    A device for attaching an experiment carrier to a space station handrail is provided. The device has two major components, a clamping mechanism for attachment to a space station handrail, and a pointing carrier on which an experiment package can be mounted and oriented. The handrail clamp uses an overcenter mechanism and the carrier mechanism uses an adjustable preload ball and socket for carrier positioning. The handrail clamp uses a stack of disk springs to provide a spring loaded button. This configuration provides consistent clamping force over a range of possible handrail thicknesses. Three load points are incorporated in the clamping mechanism thereby spreading the clamping load onto three separate points on the handrail. A four bar linkage is used to provide for a single actuation lever for all three load points. For additional safety, a secondary lock consisting of a capture plate and push lock keeps the clamp attached to the handrail in the event of main clamp failure. For the carrier positioning mechanism, a ball in a spring loaded socket uses friction to provide locking torque; however. the ball and socket are torque limited so that the ball ran slip under kick loads (125 pounds or greater). A lead screw attached to disk spring stacks is used to provide an adjustable spring force on the socket. A locking knob is attached to the lead screw to allow for hand manipulation of the lead screw.

  16. OPTIMAL TIMING FOR CLAMPING THE UMBILICAL CORD AFTER BIRTH

    PubMed Central

    Raju, Tonse N. K.; Singal, Nalini

    2013-01-01

    Synopsis This paper provides a brief overview of pros and cons of clamping the cord too early (within seconds) after birth. It also highlights evolving data that suggests that delaying cord clamping for 30–60 seconds after birth is beneficial to the baby and the mother, with no measurable negative effects. PMID:23164185

  17. Nuclear Patch-Clamp Electrophysiology of Ca2+ Channels

    PubMed Central

    Mak, Don-On Daniel; Vais, Horia; Cheung, King-Ho; Foskett, J. Kevin

    2014-01-01

    Patch-clamping the outer or inner nuclear membrane of isolated nuclei is very similar to patch-clamping the plasma membrane of isolated cells. This protocol describes in detail all the steps required to successfully obtain nuclear membrane patches, in various configurations, from both the outer and inner nuclear membranes of isolated nuclei. PMID:24003194

  18. 21 CFR 876.5160 - Urological clamp for males.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Urological clamp for males. 876.5160 Section 876.5160 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices § 876.5160 Urological clamp for males...

  19. 21 CFR 876.5160 - Urological clamp for males.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Urological clamp for males. 876.5160 Section 876.5160 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices § 876.5160 Urological clamp for males...

  20. Nontraumatic acute aortic emergencies: Part 2, Pre- and postsurgical complications related to aortic aneurysm in the emergency clinical setting.

    PubMed

    Maddu, Kiran K; Telleria, Juan; Shuaib, Waqas; Johnson, Jamlik-Omari; Khosa, Faisal

    2014-03-01

    The aim of this article is to illustrate the imaging findings and spectrum of disease entities affecting the aorta. The clinical presentation and assessment of acute aortic pathology can be elusive or deceptive, making the diagnosis challenging. The widespread availability of advanced cross-sectional imaging technology in the emergency setting puts the radiologist at the forefront of accurate and timely diagnosis. Cross-sectional imaging plays a pivotal role in the diagnosis and delineation of aortic pathology. Awareness of the imaging findings and complications can help in swift and accurate diagnosis.

  1. Efficacy of Stentless Aortic Bioprosthesis Implantation for Aortic Stenosis with Small Aortic Annulus.

    PubMed

    Murashita, Takashi; Okada, Yukikatsu; Kanemitsu, Hideo; Fukunaga, Naoto; Konishi, Yasunobu; Nakamura, Ken; Koyama, Tadaaki

    2015-09-01

    In patients with small aortic annulus, sufficient size of stented aortic bioprosthesis cannot be implanted without additional procedures. In such cases, we use stentless aortic bioprosthesis to obtain sufficient effective orifice area. In this study, we investigated long-term impact of stentless aortic bioprosthesis on clinical outcomes, compared with stented aortic bioprosthesis. We retrospectively investigated 140 patients who underwent aortic valve replacement (AVR) with porcine bioprosthesis for severe aortic stenosis between 1999 and 2010. Patients who had moderate or more aortic regurgitation and who underwent concomitant mitral procedures were excluded. A total of 69 patients (49%) were implanted stentless bioprosthesis (Freestyle group; Medtronic Inc, Minneapolis, Minnesota, United States) and 71 patients (51%) were implanted stented bioprosthesis (Mosaic group; Medtronic Inc). Follow-up was complete in 97.9% patients. Median follow-up period was 4.2 years. Patients in Freestyle group had smaller body surface area, smaller aortic annulus diameter, smaller aortic valve area, larger mean pressure gradient, higher peak velocity across aortic valve, larger left ventricular mass index (LVMI), and lower left ventricular ejection fraction (LVEF). Mean size of implanted prosthesis was larger in Freestyle group. In-hospital mortality was 1.4% in Freestyle group and 2.8% in Mosaic group (p = 0.980). Five-year survival rate was not different between two groups (5-year survival rate was 87.5 ± 4.7% in Freestyle group and 84.1 ± 7.5% in Mosaic group; log rank, p = 0.619). Late New York Heart Association functional class was lower in Freestyle group. Late LVMI and LVEF became similar between two groups. Stentless aortic bioprosthesis is superior in left ventricular remodeling after AVR for aortic stenosis and is especially effective for small aortic annulus. Georg Thieme Verlag KG Stuttgart · New York.

  2. Combined aortic valve replacement and coronary artery bypass grafting for a calcified ascending aorta.

    PubMed

    Baba, Hironori; Umesue, Masayoshi; Matsui, Kanzi

    2012-04-01

    Although a severely calcified ascending aorta is encountered infrequently, it presents formidable problems during cardiac surgery. We describe a case of severe aortic valve stenosis and coronary artery disease combined with a severely calcified ascending aorta. The patient was an 80-year-old man with a calcified ascending aorta. He successfully underwent an aortic valve replacement and a single coronary artery bypass graft (CABG) using a saphenous vein graft with the proximal end connected on a Dacron patch, which was used for aortoplasty of the calcified plate along the aortotomy. These procedures were performed under moderate hypothermia with aortic clamping. This patch aortoplasty can be a useful alternative in cases that require aortotomy and proximal anastomoses of a CABG on a calcified ascending aorta.

  3. Cell-Detection Technique for Automated Patch Clamping

    NASA Technical Reports Server (NTRS)

    McDowell, Mark; Gray, Elizabeth

    2008-01-01

    A unique and customizable machinevision and image-data-processing technique has been developed for use in automated identification of cells that are optimal for patch clamping. [Patch clamping (in which patch electrodes are pressed against cell membranes) is an electrophysiological technique widely applied for the study of ion channels, and of membrane proteins that regulate the flow of ions across the membranes. Patch clamping is used in many biological research fields such as neurobiology, pharmacology, and molecular biology.] While there exist several hardware techniques for automated patch clamping of cells, very few of those techniques incorporate machine vision for locating cells that are ideal subjects for patch clamping. In contrast, the present technique is embodied in a machine-vision algorithm that, in practical application, enables the user to identify good and bad cells for patch clamping in an image captured by a charge-coupled-device (CCD) camera attached to a microscope, within a processing time of one second. Hence, the present technique can save time, thereby increasing efficiency and reducing cost. The present technique involves the utilization of cell-feature metrics to accurately make decisions on the degree to which individual cells are "good" or "bad" candidates for patch clamping. These metrics include position coordinates (x,y) in the image plane, major-axis length, minor-axis length, area, elongation, roundness, smoothness, angle of orientation, and degree of inclusion in the field of view. The present technique does not require any special hardware beyond commercially available, off-the-shelf patch-clamping hardware: A standard patchclamping microscope system with an attached CCD camera, a personal computer with an imagedata- processing board, and some experience in utilizing imagedata- processing software are all that are needed. A cell image is first captured by the microscope CCD camera and image-data-processing board, then the image

  4. Aortic coarctation with persistent fifth left aortic arch.

    PubMed

    Santoro, Giuseppe; Caianiello, Giuseppe; Palladino, Maria Teresa; Iacono, Carola; Russo, Maria Giovanna; Calabrò, Raffaele

    2009-08-14

    A neonate with severe aortic coarctation showed a double lumen transverse aorta (persistent fifth aortic arch) with both channels joining at the isthmus where the obstruction was confirmed by echocardiography and cardiac catheterization. Surgical repair was performed with a pantaloon-shaped patch. Persistent fifth aortic arch does not result in a vascular ring and, per se, is not hemodynamically significant unless associated with other cardiac malformations.

  5. Paraplegia caused by aortic coarctation complicated with spinal epidural hemorrhage.

    PubMed

    Tsai, Yi-Da; Hsu, Chin-Wang; Hsu, Chia-Ching; Liao, Wen-I; Chen, Sy-Jou

    2016-03-01

    Aortic coarctation complicated with spinal artery aneurysm rupture is exceptionally rare and can be source of intraspinal hemorrhage with markedly poor prognosis. A 21-year-old man visited the emergency department because of chest and back pain along with immobility of bilateral lower limbs immediately after he woke up in the morning. Complete flaccid paraplegia and hypoesthesia in dermatome below bilateral T3 level and pain over axial region from neck to lumbar region were noted. A computed tomography excluded aortic dissection. Magnetic resonance imaging revealed a fusiform lesion involving the anterior epidural space from C7 to T2 level suspected of epidural hemorrhage, causing compression of spinal cord. He started intravenous corticosteroid but refused operation concerning the surgical benefits. Severe chest pain occurred with newly onset right bundle branch block that developed the other day. Coronary artery angiography revealed myocardial bridge of left anterior descending coronary artery at middle third and coarctation of aorta. He underwent thoracic endovascular aortic repair uneventfully. The patient was hemodynamically stable but with slow improvement in neurologic recovery of lower limbs. Aortic coarcation can cause paralysis by ruptured vascular aneurysms with spinal hemorrhage and chest pain that mimics acute aortic dissection. A history of hypertension at young age and aortic regurgitated murmurs may serve as clues for further diagnostic studies. Cautious and prudent evaluation and cross disciplines cares are essential for diagnosis and successful management of the disease.

  6. Assessment of aortic insufficiency by transcutaneous Doppler ultrasound.

    PubMed

    Boughner, D R

    1975-11-01

    Using a 2.2 MHZ directional Doppler ultrasound unit, the instantaneous peak aortic velocity pattern was recorded transcutaneously in 15 normal persons and 15 patients with aortic insufficiency. The transducer was positioned in the suprasternal notch and aimed posteriorly to cross the descending aortic arch at an angle approximately parallel to blood flow. The electrocardiogram, phonocardiogram, and carotid pulse tracings were recorded simultaneously. In patients with aortic insufficiency there was significant diastolic flow that was not present in normal persons. The planimetered area under the systolic and diastolic velocity tracings represents the distance forward and backward that the stroke volume moves. The ratio was used to approximate the percent regurgitation, which ranged from 9% to 68%. From left ventricular angiograms in the patients with aortic regurgitation single plane ventricular volume measurements were used to calculate ventricular output and when compared with the Fick cardiac output gave an estimate of true percent regurgitation. A strong correlation was obtained with the Doppler estimate (r=0.91), confirming that this simple ultrasound technique can accurately assess the degree of aortic insufficiency.

  7. Single electrode dynamic clamp with StdpC.

    PubMed

    Samu, David; Marra, Vincenzo; Kemenes, Ildiko; Crossley, Michael; Kemenes, György; Staras, Kevin; Nowotny, Thomas

    2012-10-15

    Dynamic clamp is a powerful approach for electrophysiological investigations allowing researchers to introduce artificial electrical components into target neurons to simulate ionic conductances, chemical or electrotonic inputs or connections to other cells. Due to the rapidly changing and potentially large current injections during dynamic clamp, problematic voltage artifacts appear on the electrode used to inject dynamic clamp currents into a target neuron. Dynamic clamp experiments, therefore, typically use two separate electrodes in the same cell, one for recording membrane potential and one for injecting currents. The requirement for two independent electrodes has been a limiting factor for the use of dynamic clamp in applications where dual recordings of this kind are difficult or impossible to achieve. The recent development of an active electrode compensation (AEC) method has overcome some of these prior limitations, permitting artifact-free dynamic clamp experimentation with a single electrode. Here we describe an AEC method for the free dynamic clamp software StdpC. The AEC component of StdpC is the first such system implemented for the use of non-expert users and comes with a set of semi-automated configuration and calibration procedures that facilitate its use. We briefly introduce the AEC method and its implementation in StdpC and then validate it with an electronic model cell and in two different biological preparations.

  8. Single electrode dynamic clamp with StdpC

    PubMed Central

    Samu, David; Marra, Vincenzo; Kemenes, Ildiko; Crossley, Michael; Kemenes, György; Staras, Kevin; Nowotny, Thomas

    2012-01-01

    Dynamic clamp is a powerful approach for electrophysiological investigations allowing researchers to introduce artificial electrical components into target neurons to simulate ionic conductances, chemical or electrotonic inputs or connections to other cells. Due to the rapidly changing and potentially large current injections during dynamic clamp, problematic voltage artifacts appear on the electrode used to inject dynamic clamp currents into a target neuron. Dynamic clamp experiments, therefore, typically use two separate electrodes in the same cell, one for recording membrane potential and one for injecting currents. The requirement for two independent electrodes has been a limiting factor for the use of dynamic clamp in applications where dual recordings of this kind are difficult or impossible to achieve. The recent development of an active electrode compensation (AEC) method has overcome some of these prior limitations, permitting artifact-free dynamic clamp experimentation with a single electrode. Here we describe an AEC method for the free dynamic clamp software StdpC. The AEC component of StdpC is the first such system implemented for the use of non-expert users and comes with a set of semi-automated configuration and calibration procedures that facilitate its use. We briefly introduce the AEC method and its implementation in StdpC and then validate it with an electronic model cell and in two different biological preparations. PMID:22898473

  9. Effect of delayed umbilical cord clamping on blood gas analysis.

    PubMed

    Valero, Javier; Desantes, Domingo; Perales-Puchalt, Alfredo; Rubio, Juan; Diago Almela, Vicente J; Perales, Alfredo

    2012-05-01

    To ascertain if there are differences in umbilical cord blood gas analysis between immediate and delayed cord clamping. In a prospective observational study on 60 vaginally delivered healthy term newborns, we sampled umbilical cord blood immediately after delivery and at the time umbilical cord pulsation spontaneously ceased. There were significant decreases in pH, oxygen saturation (sO(2)), glycemia, oxygen content (ctO(2)), bicarbonate (HCO(3)(-)) and base excess (BE). Lactate and [Formula: see text] increased. Delayed cord clamping pH correlated with immediate cord clamping pH, [Formula: see text] , ctHb, sO(2) and time (r(2)=0.77, p<0.000). Delayed cord clamping lactate was associated with immediate cord clamping lactate and time (r(2)=0.83, p<0.000). Delayed BE was associated with previous pH, lactate, glycemia, ctHb and time (r(2)=0.83, p<0.000). Delayed cord clamping alters acid-base parameters and lactate values compared to immediate cord clamping. Those variations depend mainly on time, prior pH and lactate. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  10. Committee Opinion No. 684: Delayed Umbilical Cord Clamping After Birth.

    PubMed

    2017-01-01

    Delayed umbilical cord clamping appears to be beneficial for term and preterm infants. In term infants, delayed umbilical cord clamping increases hemoglobin levels at birth and improves iron stores in the first several months of life, which may have a favorable effect on developmental outcomes. There is a small increase in jaundice that requires phototherapy in this group of infants. Consequently, health care providers adopting delayed umbilical cord clamping in term infants should ensure that mechanisms are in place to monitor for and treat neonatal jaundice. In preterm infants, delayed umbilical cord clamping is associated with significant neonatal benefits, including improved transitional circulation, better establishment of red blood cell volume, decreased need for blood transfusion, and lower incidence of necrotizing enterocolitis and intraventricular hemorrhage. Delayed umbilical cord clamping was not associated with an increased risk of postpartum hemorrhage or increased blood loss at delivery, nor was it associated with a difference in postpartum hemoglobin levels or the need for blood transfusion. Given the benefits to most newborns and concordant with other professional organizations, the American College of Obstetricians and Gynecologists now recommends a delay in umbilical cord clamping in vigorous term and preterm infants for at least 30-60 seconds after birth. The ability to provide delayed umbilical cord clamping may vary among institutions and settings; decisions in those circumstances are best made by the team caring for the mother-infant dyad.

  11. Prevalence of coronary atherosclerosis in patients with aortic valve replacement

    PubMed Central

    Ottervanger, J.P.; Thomas, K.; Sie, T.H.; Haalebos, M.M.P.; Zijlstra, F.

    2002-01-01

    Background Because of a high prevalence of coronary artery disease in patients with aortic valve disease, coronary angiography is recommended before aortic valve replacement. However, during the last three decades, a decline in mortality due to coronary heart disease has been observed in the general population in both Western Europe and the United States. It is unknown whether preoperative angiography is still mandatory in all patients. Aim To assess the prevalence of angiographically defined coronary artery disease in patients with aortic valve replacement and trends during a ten-year period. Methods We performed a retrospective cross-sectional study of patients undergoing aortic valve replacement between 1988 and 1998 in our institution. Patients with a history of coronary artery disease and patients younger than 25 years were excluded. Coronary atherosclerosis was defined as one or more coronary artery luminal stenosis of 50% or more on preoperative coronary angiography. Results During the study period 1339 patients had aortic valve replacement in our institution, data on 1322 (98%) were available for analysis. Previous coronary artery disease was documented in 124 patients (10%). After exclusion of 17 patients (no angiography), data on a total of 1181 patients were analysed. Coronary atherosclerosis was present in 472 patients (40%) on preoperative coronary angiography. Several well-known risk factors of ischaemic heart disease were associated with coronary atherosclerosis. The prevalence of angiographically defined coronary atherosclerosis varied between 30% and 50% per year. There was, however, no significant trend during the study period. Multivariate analyses, to adjust for potential differences in risk factors during the observation period, did not change this conclusion. Conclusions The prevalence of angiographically defined coronary artery disease in patients scheduled for aortic valve replacement is still high. From 1988 to 1998, no significant change

  12. Genetics Home Reference: supravalvular aortic stenosis

    MedlinePlus

    ... Genetics Home Health Conditions supravalvular aortic stenosis supravalvular aortic stenosis Enable Javascript to view the expand/collapse boxes. Download PDF Open All Close All Description Supravalvular aortic stenosis (SVAS) is a heart defect that develops before ...

  13. [Stent Grafting for Aortic Dissection].

    PubMed

    Uchida, Naomichi

    2016-07-01

    The purpose of stent graft for aortic dissection is to terminate antegrade blood flow into the false lumen through primary entry. Early intervention for primary entry makes excellent aortic remodeling and emergent stent grafting for complicated acute type B aortic dissection is supported as a class I. On the other hand stent grafting for chronic aortic dissection is controversial. Early stent grafting is considered with in 6 months after on-set if the diameter of the descending aorta is more than 40 mm. Additional interventions for residual false lumen on the downstream aorta are still required. Stent graft for re-entry, candy-plug technique, and double stenting, other effective re-interventions were reported. Best treatment on the basis of each anatomical and physical characteristics should be selected in each institution. Frozen elephant trunk is alternative procedure for aortic dissection without the need to take account of proximal anatomical limitation and effective for acute type A aortic dissection.

  14. A New Murine Model of Endovascular Aortic Aneurysm Repair

    PubMed Central

    Rouer, Martin; Meilhac, Olivier; Delbosc, Sandrine; Louedec, Liliane; Pavon-Djavid, Graciela; Cross, Jane; Legagneux, Josette; Bouilliant-Linet, Maxime; Michel, Jean-Baptiste; Alsac, Jean-Marc

    2013-01-01

    Endovascular aneurysm exclusion is a validated technique to prevent aneurysm rupture. Long-term results highlight technique limitations and new aspects of Abdominal aortic aneurysm (AAA) pathophysiology. There is no abdominal aortic aneurysm endograft exclusion model cheap and reproducible, which would allow deep investigations of AAA before and after treatment. We hereby describe how to induce, and then to exclude with a covered coronary stentgraft an abdominal aortic aneurysm in a rat. The well known elastase induced AAA model was first reported in 19901 in a rat, then described in mice2. Elastin degradation leads to dilation of the aorta with inflammatory infiltration of the abdominal wall and intra luminal thrombus, matching with human AAA. Endovascular exclusion with small covered stentgraft is then performed, excluding any interactions between circulating blood and the aneurysm thrombus. Appropriate exclusion and stentgraft patency is confirmed before euthanasia by an angiography thought the left carotid artery. Partial control of elastase diffusion makes aneurysm shape different for each animal. It is difficult to create an aneurysm, which will allow an appropriate length of aorta below the aneurysm for an easy stentgraft introduction, and with adequate proximal and distal neck to prevent endoleaks. Lots of failure can result to stentgraft introduction which sometimes lead to aorta tear with pain and troubles to stitch it, and endothelial damage with post op aorta thrombosis. Giving aspirin to rats before stentgraft implantation decreases failure rate without major hemorrhage. Clamping time activates neutrophils, endothelium and platelets, and may interfere with biological analysis. PMID:23851958

  15. Reciprocating clamp apparatus for thermoforming plastic containers

    SciTech Connect

    Beck, M.H.; Harry, I.L.; Krishnakumar, S.M.

    1984-03-06

    This relates to the forming of containers and like hollow articles from sheets or webs of thermoplastic material. Two webs or sheets are simultaneously acted upon by way of a forming apparatus which includes a reciprocating clamp first cooperable with one outer platen and then the other in sequence wherein, while a first web or sheet is being formed within a plurality of mold cavities to define a plurality of hollow articles such as containers, the other sheet or web may be stripped from its respective mold set and a new sheet or a new portion of a sheet or web may be advanced into position for molding. The forming apparatus may be constructed in a manner wherein the web portions which are to be formed may be billowed away from the mold cavities as an initial step in the stretching and orientation of the thermoplastic material. The thermoplastic material may be heated to the desired forming temperature using separate sets of rf electrodes so that only those portions of the thermoplastic material which are to be formed need be heated. Two sets of containers of different sizes may be formed from the webs or sheets, and then internested to form double wall containers wherein the walls may be formed of different materials and wherein the outer material may be a barrier material, or wherein the walls of the containers are spaced apart to form an insulated container. This abstract forms no part of the specification of this application and is not to be construed as limiting the claims of the application.

  16. Ruptured abdominal aortic aneurysm.

    PubMed

    Sachs, T; Schermerhorn, M

    2010-06-01

    Ruptured abdominal aortic aneurysm (AAA) continues to be one of the most lethal vascular pathologies we encounter. Its management demands prompt and efficient evaluation and repair. Open repair has traditionally been the mainstay of treatment. However, the introduction of endovascular techniques has altered the treatment algorithm for ruptured AAA in most major medical centers. We present recent literature and techniques for ruptured AAA and its surgical management.

  17. Aortic dimensions in Turner syndrome.

    PubMed

    Quezada, Emilio; Lapidus, Jodi; Shaughnessy, Robin; Chen, Zunqiu; Silberbach, Michael

    2015-11-01

    In Turner syndrome, linear growth is less than the general population. Consequently, to assess stature in Turner syndrome, condition-specific comparators have been employed. Similar reference curves for cardiac structures in Turner syndrome are currently unavailable. Accurate assessment of the aorta is particularly critical in Turner syndrome because aortic dissection and rupture occur more frequently than in the general population. Furthermore, comparisons to references calculated from the taller general population with the shorter Turner syndrome population can lead to over-estimation of aortic size causing stigmatization, medicalization, and potentially over-treatment. We used echocardiography to measure aortic diameters at eight levels of the thoracic aorta in 481 healthy girls and women with Turner syndrome who ranged in age from two to seventy years. Univariate and multivariate linear regression analyses were performed to assess the influence of karyotype, age, body mass index, bicuspid aortic valve, blood pressure, history of renal disease, thyroid disease, or growth hormone therapy. Because only bicuspid aortic valve was found to independently affect aortic size, subjects with bicuspid aortic valve were excluded from the analysis. Regression equations for aortic diameters were calculated and Z-scores corresponding to 1, 2, and 3 standard deviations from the mean were plotted against body surface area. The information presented here will allow clinicians and other caregivers to calculate aortic Z-scores using a Turner-based reference population. © 2015 Wiley Periodicals, Inc.

  18. Abdominal aortic aneurysms.

    PubMed

    Lindholt, Jes Sanddal

    2010-12-01

    Although the number of elective operations for abdominal aortic aneurysms (AAA) is increasing, the sex- and age-standardised mortality rate of AAAs continues to rise, especially among men aged 65 years or more. The lethality of ruptured AAA continues to be 80-95%, compared with 5-7% by elective surgery of symptomfree AAA. In order to fulfil all WHO, European, and Danish criteria for screening, a randomised hospitalbased screening trial of 12,639 65-73 year old men in Viborg County (Denmark) was initiated in 1994. It seemed that US screening is a valid, suitable and acceptable method of screening. The acceptance rate was 77%, and 95% accept control scans. Furthermore, persons at the highest risk of having an AAA attend screening more frequently. We found that 97% of the interval cases developed from aortas that initially measured 2.5-2.9 cm - i.e. approx. only 5% attenders need re-screening at 5-year intervals. Two large RCTs have given clear indications of operation. Survivors of surgery enjoy the same quality of life as the background population, and only 2-5% of patients refuse an offer of surgery. Early detection seems relevant since the cardiovascular mortality is more than 4 times higher in AAA patients without previous hospital discharge diagnoses due to cardiovascular disease than among similar men without AAA. The absolute risk difference after 5 years was 16%. So, they will benefit from general cardiovascular preventive action as smoking cessation, statins and low-dose aspirin, which could inhibit further AAA progression. All 4 existing RCTs point in the same direction, viz. in favour of screening of men aged 65 and above. We found that screening significantly reduced AAA-related mortality by 67% within the first five years (NNT = 352). Restriction of screening to men with previous cardiovascular or pulmonary hospital discharge diagnoses would request only 27% of the relevant male population study to be invited, but would only have prevented 46.7% of the

  19. Prediction of Shock Response and Methods to Mitigate the Shock Response Produced by V-Section Band Clamps Using a Simplified Dynamic Model

    NASA Astrophysics Data System (ADS)

    Shi, Qinzhong; Tomoya, Niwa; Wada, Yoshio

    2012-07-01

    V-section band clamps are widely used for connecting payload and launch vehicle in space application. The mechanical principle of V-band clamp uses the clamp nut which tightens the clamp to result in a radial force on the ring flange to generate an axial load to restrain the payload on payload adapter. Release of V-band clamp by pyrotechnic actuator generates high shock acceleration in both magnitude and frequency, which may damage functions of the sensitive electromechanical equipment. Prediction and mitigation technology of shock acceleration of V-band clamps are necessary to the payload design, verification. This paper proposes a simplified model to analysis the shock acceleration of dominating mode which decides the knee frequency and the magnitude of shock response spectrum (SRS). The dominating mode of ring flange may be calculated from the structural parameters of V- band, such as materials, cross-section of the ring flange, and the clamp preload. Besides dominating mode, high modes which may excited depends on load distribution along the ring flange is investigated by mode participating factor of each modes. The envelope tolerance of SRS is calculated statistically based on the deviation between the analysis model and test data, obtained from several satellite shock test. Finally, mitigation of shock acceleration of V-band by the way of extension of load release time is simulated.

  20. User-assisted aortic aneurysm analysis

    NASA Astrophysics Data System (ADS)

    Ouvrard, Amandine; Renapuraar, Rahul; Setser, Randolph M.; Flamm, Scott; O'Donnell, Thomas

    2009-02-01

    Aortic Aneurysms (AA) are the 13th leading cause of death in the US. In standard clinical practice, intervention is initiated when the maximal diameter cross-sectional reaches 5.5cm. However, this is a 1D measure and it has been suggested in the literature that higher order measurements (area, volume) might be more appropriate clinically. Unfortunately, no commercially available tools exist for extracting a 3D model of the epithelial layer (versus the lumen) of the vessel. Therefore, we present work towards semi-automatically recovering the aorta from CT angiography volumes with the aim to facilitate such studies. We build our work upon a previous approach to this problem. Bodur et. al., presented a variant of the iso-perimetric algorithm to semi-automatically segment several individual aortic cross-sections across longitudinal studies, quantifying any growth. As a by-product of these sparse cross-sections, it is possible to form a series of rough 3D models of the aorta. In this work we focus on creating a more detailed 3D model at a single time point by automatically recovering the aorta between the sparse user-initiated segmentations. Briefly, we fit a tube model to the sparse segmentations to approximate the cross-sections at intermediate regions, refine the approximations and apply the isoperimetric algorithm to them. From these resulting dense cross-sections we reconstruct our model. We applied our technique to 12 clinical datasets which included significant amounts of thrombus. Comparisons of the automatically recovered cross-sections with cross-sections drawn by an expert resulted in an average difference of .3cm for diameter and 2cm^2 for area.

  1. The Application of Mechanical Clamps to Portsmouth Connectors.

    DTIC Science & Technology

    1981-11-23

    Resistance Readings ..... .............. .64 TABLE 12 - ALT SUMM!ARY - POLYURETHANE CONNECTORS Resis- ance Readings ..... .............. .65 v7 ft...34 FIGURE 17 Pressure Tank Pressure Fittings . ........ . 37 vi I THE APPLICATION OF MECHANICAL CLAMPS TO PORTSMOUTH CONNECTORS BACKGROUN )D This

  2. Studying mechanosensitive ion channels with an automated patch clamp.

    PubMed

    Barthmes, Maria; Jose, Mac Donald F; Birkner, Jan Peter; Brüggemann, Andrea; Wahl-Schott, Christian; Koçer, Armağan

    2014-03-01

    Patch clamp electrophysiology is the main technique to study mechanosensitive ion channels (MSCs), however, conventional patch clamping is laborious and success and output depends on the skills of the operator. Even though automated patch systems solve these problems for other ion channels, they could not be applied to MSCs. Here, we report on activation and single channel analysis of a bacterial mechanosensitive ion channel using an automated patch clamp system. With the automated system, we could patch not only giant unilamellar liposomes but also giant Escherichia coli (E. coli) spheroplasts. The tension sensitivity and channel kinetics data obtained in the automated system were in good agreement with that obtained from the conventional patch clamp. The findings will pave the way to high throughput fundamental and drug screening studies on mechanosensitive ion channels.

  3. A clamp-like biohybrid catalyst for DNA oxidation

    NASA Astrophysics Data System (ADS)

    van Dongen, Stijn F. M.; Clerx, Joost; Nørgaard, Kasper; Bloemberg, Tom G.; Cornelissen, Jeroen J. L. M.; Trakselis, Michael A.; Nelson, Scott W.; Benkovic, Stephen J.; Rowan, Alan E.; Nolte, Roeland J. M.

    2013-11-01

    In processive catalysis, a catalyst binds to a substrate and remains bound as it performs several consecutive reactions, as exemplified by DNA polymerases. Processivity is essential in nature and is often mediated by a clamp-like structure that physically tethers the catalyst to its (polymeric) template. In the case of the bacteriophage T4 replisome, a dedicated clamp protein acts as a processivity mediator by encircling DNA and subsequently recruiting its polymerase. Here we use this DNA-binding protein to construct a biohybrid catalyst. Conjugation of the clamp protein to a chemical catalyst with sequence-specific oxidation behaviour formed a catalytic clamp that can be loaded onto a DNA plasmid. The catalytic activity of the biohybrid catalyst was visualized using a procedure based on an atomic force microscopy method that detects and spatially locates oxidized sites in DNA. Varying the experimental conditions enabled switching between processive and distributive catalysis and influencing the sliding direction of this rotaxane-like catalyst.

  4. Diffusion of Alexa Fluor 488-conjugated dendrimers in rat aortic tissue.

    PubMed

    Cho, Brenda S; Roelofs, Karen J; Majoros, Istvan J; Baker, James R; Stanley, James C; Henke, Peter K; Upchurch, Gilbert R

    2006-11-01

    In this study, the distribution of labeled dendrimers in native and aneurysmal rat aortic tissue was examined. Adult male rats underwent infrarenal aorta perfusion with generation 5 (G5) acetylated Alexa Fluor 488-conjugated dendrimers for varying lengths of time. In a second set of experiments, rats underwent aortic elastase perfusion followed by aortic dendrimer perfusion 7 days later. Aortic diameters were measured prior to and postelastase perfusion, and again on the day of harvest. Aortas were harvested 0, 12, or 24 h postperfusion, fixed, and mounted. Native aortas were harvested and viewed as negative controls. Aortic cross-sections were viewed and imaged using confocal microscopy. Dendrimers were quantified (counts/high-powered field). Results were evaluated by repeated measures ANOVA and Student's t-test. We found that in native aortas, dendrimers penetrated the aortic wall in all groups. For all perfusion times, fewer dendrimers were present as time between dendrimer perfusion and aortic harvest increased. Longer perfusion times resulted in increased diffusion of dendrimers throughout the aortic wall. By 24 h, the majority of the dendrimers were through the wall. Dendrimers in aneurysmal aortas, on day 0 postdendrimer perfusion, diffused farther into the aortic wall than controls. In conclusion, this study documents labeled dendrimers delivered intra-arterially to native rat aortas in vivo, and the temporal diffusion of these molecules within the aortic wall. Increasing perfusion time and length of time prior to harvest resulted in continued dendrimer diffusion into the aortic wall. These preliminary data provide a novel mechanism whereby local inhibitory therapy may be delivered locally to aortic tissue.

  5. Spatial dynamics, thermalization, and gain clamping in a photon condensate

    NASA Astrophysics Data System (ADS)

    Keeling, Jonathan; Kirton, Peter

    2016-01-01

    We study theoretically the effects of pump-spot size and location on photon condensates. By exploring the inhomogeneous molecular excitation fraction, we make clear the relation between spatial equilibration, gain clamping, and thermalization in a photon condensate. This provides a simple understanding of several recent experimental results. We find that as thermalization breaks down, gain clamping is imperfect, leading to "transverse spatial hole burning" and multimode condensation. This opens the possibility of engineering the gain profile to control the condensate structure.

  6. Lotus birth, a holistic approach on physiological cord clamping.

    PubMed

    Zinsser, Laura A

    2017-09-04

    The positive effects of delayed cord clamping (DCC) has been extensively researched. DCC means: waiting at least one minute after birth before clamping and cutting the cord or till the pulsation has stopped. With physiological clamping and cutting (PCC) the clamping and cutting can happen at the earliest after the pulsation has stopped. With a Lotus birth, no clamping and cutting of the cord is done. A woman called Clair Lotus Day imitated the holistic approach of PCC from an anthropoid ape in 1974. The chimpanzee did not separate the placenta from the newborn. The aim of this case report is to discuss and learn a different approach in the third stage of labour. Three cases of Lotus birth by human beings were observed. All three women gave birth in an out-of-hospital setting and had ambulant postnatal care. The placenta was washed, salted and herbs were put on 2-3h post partum. The placenta was wrapped in something that absorbs the moisture. The salting was repeated with a degreasing frequency depending on moistness of the placenta. On life day six all three Lotus babies experiences a natural separation of the cord. All three Lotus birth cases were unproblematic, no special incidence occurred. One should differentiate between early cord clamping (ECC), delayed cord clamping (DCC) and physiological cord clamping (PCC). Lotus birth might lead to an optimisation of the bonding and attachment. Research is needed in the areas of both PCC and Lotus birth. Copyright © 2017 Australian College of Midwives. Published by Elsevier Ltd. All rights reserved.

  7. Management of Acute Aortic Syndrome and Chronic Aortic Dissection

    SciTech Connect

    Nordon, Ian M. Hinchliffe, Robert J.; Loftus, Ian M.; Morgan, Robert A.; Thompson, Matt M.

    2011-10-15

    Acute aortic syndrome (AAS) describes several life-threatening aortic pathologies. These include intramural hematoma, penetrating aortic ulcer, and acute aortic dissection (AAD). Advances in both imaging and endovascular treatment have led to an increase in diagnosis and improved management of these often catastrophic pathologies. Patients, who were previously consigned to medical management or high-risk open surgical repair, can now be offered minimally invasive solutions with reduced morbidity and mortality. Information from the International Registry of Acute Aortic Dissection (IRAD) database demonstrates how in selected patients with complicated AAD the 30-day mortality from open surgery is 17% and endovascular stenting is 6%. Despite these improvements in perioperative deaths, the risks of stroke and paraplegia remain with endovascular treatment (combined outcome risk 4%). The pathophysiology of each aspect of AAS is described. The best imaging techniques and the evolving role of endovascular techniques in the definitive management of AAS are discussed incorporating strategies to reduce perioperative morbidity.

  8. Retrograde lower body arterial reservoir discharge underlies rapid reversal of ductus arteriosus shunting after early cord clamping at birth in preterm lambs.

    PubMed

    Smolich, Joseph J; Kenna, Kelly R; Mynard, Jonathan P

    2016-02-15

    Arterial reservoir ("windkessel") function, whereby a part of left ventricular (LV) output is stored in elastic arteries during systole and discharged in diastole, is a well-established physiological phenomenon. However, its role in rapid reversal (to left-to-right) and a systolic-to-diastolic shift of shunting across the ductus arteriosus after birth is unknown. To address this question, ductal and aortic isthmus flows were measured with high-fidelity transit-time probes in six anesthetized preterm fetal lambs before and after cord clamping and subsequent early mechanical ventilation and for 30 min postbirth. Descending aortic flow was calculated as the sum of isthmus and ductal flows. Left-to-right ductal flow profiles were related to those of the isthmus and descending aorta, with upper body arterial reservoir discharge indicated by forward diastolic isthmus flow, and retrograde lower body arterial reservoir discharge by negative diastolic descending aortic flow. Left-to-right ductal shunting appeared immediately after cord clamping (P < 0.001), due entirely to newly emergent retrograde lower body reservoir discharge, and rose with ventilation via increased lower body reservoir discharge (P < 0.005), supplemented by upper body reservoir discharge after 45 s (P < 0.025) and LV systolic flow after 3 min (P = 0.025). The contribution of lower body reservoir discharge to left-to-right ductal shunting fell to 55 ± 8% at ≥15 min (P < 0.001) but remained higher (P < 0.002) than LV systolic flow (33 ± 8%) or upper body reservoir discharge (12 ± 5%). These results suggest that retrograde lower body arterial reservoir discharge plays a key role in rapid reversal and a systolic-to-diastolic shift of ductal shunting after cord clamping and early ventilation at birth.

  9. Spectrum of aortic valve abnormalities associated with aortic dilation across age groups in Turner syndrome.

    PubMed

    Olivieri, Laura J; Baba, Ridhwan Y; Arai, Andrew E; Bandettini, W Patricia; Rosing, Douglas R; Bakalov, Vladimir; Sachdev, Vandana; Bondy, Carolyn A

    2013-11-01

    Congenital aortic valve fusion is associated with aortic dilation, aneurysm, and rupture in girls and women with Turner syndrome. Our objective was to characterize aortic valve structure in subjects with Turner syndrome and to determine the prevalence of aortic dilation and valve dysfunction associated with different types of aortic valves. The aortic valve and thoracic aorta were characterized by cardiovascular MRI in 208 subjects with Turner syndrome in an institutional review board-approved natural history study. Echocardiography was used to measure peak velocities across the aortic valve and the degree of aortic regurgitation. Four distinct valve morphologies were identified: tricuspid aortic valve, 64% (n=133); partially fused aortic valve, 12% (n=25); bicuspid aortic valve, 23% (n=47); and unicuspid aortic valve, 1% (n=3). Age and body surface area were similar in the 4 valve morphology groups. There was a significant trend, independent of age, toward larger body surface area-indexed ascending aortic diameters with increasing valve fusion. Ascending aortic diameters were (mean±SD) 16.9±3.3, 18.3±3.3, and 19.8±3.9 mm/m(2) (P<0.0001) for tricuspid aortic valve, partially fused aortic valve, and bicuspid aortic valve+unicuspid aortic valve, respectively. Partially fused aortic valve, bicuspid aortic valve, and unicuspid aortic valve were significantly associated with mild aortic regurgitation and elevated peak velocities across the aortic valve. Aortic valve abnormalities in Turner syndrome occur with a spectrum of severity and are associated with aortic root dilation across age groups. Partial fusion of the aortic valve, traditionally regarded as an acquired valve problem, had an equal age distribution and was associated with an increased ascending aortic diameters.

  10. Ventilation Onset Prior to Umbilical Cord Clamping (Physiological-Based Cord Clamping) Improves Systemic and Cerebral Oxygenation in Preterm Lambs

    PubMed Central

    Polglase, Graeme R.; Dawson, Jennifer A.; Kluckow, Martin; Gill, Andrew W.; Davis, Peter G.; te Pas, Arjan B.; Crossley, Kelly J.; McDougall, Annie; Wallace, Euan M.; Hooper, Stuart B.

    2015-01-01

    Background As measurement of arterial oxygen saturation (SpO2) is common in the delivery room, target SpO2 ranges allow clinicians to titrate oxygen therapy for preterm infants in order to achieve saturation levels similar to those seen in normal term infants in the first minutes of life. However, the influence of the onset of ventilation and the timing of cord clamping on systemic and cerebral oxygenation is not known. Aim We investigated whether the initiation of ventilation, prior to, or after umbilical cord clamping, altered systemic and cerebral oxygenation in preterm lambs. Methods Systemic and cerebral blood-flows, pressures and peripheral SpO2 and regional cerebral tissue oxygenation (SctO2) were measured continuously in apnoeic preterm lambs (126±1 day gestation). Positive pressure ventilation was initiated either 1) prior to umbilical cord clamping, or 2) after umbilical cord clamping. Lambs were monitored intensively prior to intervention, and for 10 minutes following umbilical cord clamping. Results Clamping the umbilical cord prior to ventilation resulted in a rapid decrease in SpO2 and SctO2, and an increase in arterial pressure, cerebral blood flow and cerebral oxygen extraction. Ventilation restored oxygenation and haemodynamics by 5–6 minutes. No such disturbances in peripheral or cerebral oxygenation and haemodynamics were observed when ventilation was initiated prior to cord clamping. Conclusion The establishment of ventilation prior to umbilical cord clamping facilitated a smooth transition to systemic and cerebral oxygenation following birth. SpO2 nomograms may need to be re-evaluated to reflect physiological management of preterm infants in the delivery room. PMID:25689406

  11. Ventilation onset prior to umbilical cord clamping (physiological-based cord clamping) improves systemic and cerebral oxygenation in preterm lambs.

    PubMed

    Polglase, Graeme R; Dawson, Jennifer A; Kluckow, Martin; Gill, Andrew W; Davis, Peter G; Te Pas, Arjan B; Crossley, Kelly J; McDougall, Annie; Wallace, Euan M; Hooper, Stuart B

    2015-01-01

    As measurement of arterial oxygen saturation (SpO2) is common in the delivery room, target SpO2 ranges allow clinicians to titrate oxygen therapy for preterm infants in order to achieve saturation levels similar to those seen in normal term infants in the first minutes of life. However, the influence of the onset of ventilation and the timing of cord clamping on systemic and cerebral oxygenation is not known. We investigated whether the initiation of ventilation, prior to, or after umbilical cord clamping, altered systemic and cerebral oxygenation in preterm lambs. Systemic and cerebral blood-flows, pressures and peripheral SpO2 and regional cerebral tissue oxygenation (SctO2) were measured continuously in apnoeic preterm lambs (126±1 day gestation). Positive pressure ventilation was initiated either 1) prior to umbilical cord clamping, or 2) after umbilical cord clamping. Lambs were monitored intensively prior to intervention, and for 10 minutes following umbilical cord clamping. Clamping the umbilical cord prior to ventilation resulted in a rapid decrease in SpO2 and SctO2, and an increase in arterial pressure, cerebral blood flow and cerebral oxygen extraction. Ventilation restored oxygenation and haemodynamics by 5-6 minutes. No such disturbances in peripheral or cerebral oxygenation and haemodynamics were observed when ventilation was initiated prior to cord clamping. The establishment of ventilation prior to umbilical cord clamping facilitated a smooth transition to systemic and cerebral oxygenation following birth. SpO2 nomograms may need to be re-evaluated to reflect physiological management of preterm infants in the delivery room.

  12. Nonlinear response of a clamped-clamped beam with internal resonance under sinusoidal excitation

    NASA Astrophysics Data System (ADS)

    Afaneh, Abdul-Hafiz Ahmed

    1992-01-01

    The nonlinear response characteristics of a clamped-clamped beam is investigated analytically, numerically, and experimentally. The beam is under an initial static axial load and subjected to a harmonic excitation of its support. Two ranges of the axial load are considered. These are below (the beam is initially straight) and above Euler buckling load (the beam is initially buckled). Hamilton's principle is used to derive a fourth order partial differential equation of motion which is descritized and reduced to a set of second order ordinary differential equations by applying Galerkin's method. Under certain values of the static load, the normal modes are nonlinearly coupled and this coupling results in a fourth order internal resonance condition between the first three modes when the beam is initially straight. Second and third order internal resonance conditions occur between the first two modes for the case of initially buckled beam. The multiple scales method showed the significant effects of these internal resonance conditions on the system behavior. In the straight beam case, the third mode which is externally excited transfers energy to the first two modes within a small range of internal detuning. Outside this region, the response is governed by a unimodal response of the third mode. In the neighborhood of 1:1 internal resonance, it is found that within the region of two mode interaction, the solution is either stationary or nonstationary depending on the excitation level and system parameters. Saturation and jump phenomena are found to take place in the case of two mode interaction with 2:1 internal resonance. Numerical simulation and experimental testing confirmed these predictions and revealed the occurrence of multifurcation, snap-through (escaping from one well to the other in an irregular manner), and chaotic motion.

  13. Overproduction and purification of RFC-related clamp loaders and PCNA-related clamps from Saccharomyces cerevisiae.

    PubMed

    Bylund, Göran O; Majka, Jerzy; Burgers, Peter M J

    2006-01-01

    The replication clamp PCNA and its loader RFC (Replication Factor C) are central factors required for processive replication and coordinated DNA repair. Recently, several additional related clamp loaders have been identified. These alternative clamp loaders contain the small Rfc2-5 subunits of RFC, but replace the large Rfc1 subunit by a pathway-specific alternative large subunit, Rad24 for the DNA damage checkpoint, Ctf18 for the establishment of sister chromatid cohesion, and Elg1 for a general function in chromosome stability. In order to define biochemical functions for these loaders, the loaders were overproduced in yeast and purified at a milligram scale. To aid in purification, the large subunit of each clamp loader was fused to a GST-tag that, after purification could be easily removed by a rhinoviral protease. This methodology yielded all clamp loaders in high yield and with high enzymatic activity. The yeast 9-1-1 checkpoint clamp, consisting of Rad17, Mec3, and Ddc1, was overproduced and purified in a similar manner.

  14. Robotic-assisted aortic surgery with and without minilaparotomy for complicated occlusive disease and aneurysm.

    PubMed

    Lin, Judith C; Kaul, Sanjeev A; Bhandari, Akshay; Peterson, Edward L; Peabody, James O; Menon, Mani

    2012-01-01

    Published reports of robotic-assisted aortic surgery involve a combination of laparoscopy for aortic dissection and a robotic system for vascular reconstruction. The objective of this study is to determine the feasibility and advantage of a total robotic-assisted aortic dissection and vascular reconstruction vs robotic-assisted aortic procedures for aortoiliac occlusive disease (AIOD) and abdominal aortic aneurysm (AAA). From February 2006 to August 2010, 21 patients were selected for robotic-assisted aortic procedures: aortobifemoral bypass in 12, AAA repair in 6, iliac aneurysm repair in 1, and ligation of type II endoleak after endovascular aneurysm repair in 2. Inclusion criteria included AAA >5 cm, iliac aneurysm >3 cm, and AIOD TransAtlantic InterSociety Classification (TASC) C or D lesions. The da Vinci S Surgical System (Intuitive Surgical Inc, Sunnyvale, Calif) was used for the abdominal aortic dissection in all cases and for the aortic anastomosis in three cases. The 21 patients (6 women, 15 men) were an average age of 65.7 years (range, 44-86 years), had a body mass index (BMI) of 27.23 kg/m(2), and 90.4% were American Society of Anesthesiologists (ASA) class 3 or 4. Robotic dissection of the abdominal aorta was successful in 20 patients (95.2%). One patient required full conversion to open AAA repair due to trocar injury. Of the remaining 20 patients, the average robotic dissection time of the infrarenal aorta was 113.1 minutes, and the average aortic clamp time was 86 minutes. The procedure in 15 patients was performed with a minilaparotomy using an average abdominal incision of 13 cm to implant the Dacron or polytetrafluoroethylene graft. Five patients underwent a total robotic-assisted procedure with robotic aortic reconstruction or ligation of a type II endoleak. The 30-day survival rate was 100%. Median length of stay was 7.5 days. All grafts were patent at a median follow-up of 32.0 months. For aortic procedures completed total robotically without

  15. Aortic PWV in Chronic Kidney Disease: A CRIC Ancillary Study

    PubMed Central

    Townsend, Raymond R.; Wimmer, Neil J.; Chirinos, Julio A.; Parsa, Afshin; Weir, Matthew; Perumal, Kalyani; Lash, James P.; Chen, Jing; Steigerwalt, Susan P.; Flack, John; Go, Alan S.; Rafey, Mohammed; Rahman, Mahboob; Sheridan, Angela; Gadegbeku, Crystal A.; Robinson, Nancy A.; Joffe, Marshall

    2009-01-01

    Background Aortic PWV is a measure of arterial stiffness and has proved useful in predicting cardiovascular morbidity and mortality in several populations of patients, including the healthy elderly, hypertensives and those with end stage renal disease receiving hemodialysis. Little data exist characterizing aortic stiffness in patients with chronic kidney disease who are not receiving dialysis, and in particular the effect of reduced kidney function on aortic PWV. Methods We performed measurements of aortic PWV in a cross-sectional cohort of participants enrolled in the Chronic Renal Insufficiency Cohort (CRIC) study to determine factors which predict increased aortic PWV in chronic kidney disease. Results PWV measurements were obtained in 2564 participants. The tertiles of aortic PWV (adjusted for waist circumference) were < 7.7 m/sec, 7.7–10.2 m/sec and > 10.2 m/sec with an overall mean (± S.D.) value of 9.48 ± 3.03 m/sec [95% CI = 9.35–9.61 m/sec]. Multivariable regression identified significant independent positive associations of age, blood glucose concentrations, race, waist circumference, mean arterial blood pressure, gender, and presence of diabetes with aortic PWV and a significant negative association with the level of kidney function. Conclusions The large size of this unique cohort, and the targeted enrollment of chronic kidney disease participants provides an ideal situation to study the role of reduced kidney function as a determinant of arterial stiffness. Arterial stiffness may be a significant component of the enhanced cardiovascular risk associated with kidney failure. PMID:20019670

  16. [Aortic valve replacement for the small aortic annulus].

    PubMed

    Oshima, H; Usui, A; Akita, T; Ueda, Y

    2006-04-01

    Aortic valve surgery for the small aortic annulus is still challenging for surgeons. Recently, the new types of high performance prosthesis have been developed and the chance of an aortic root enlargement (ARE) is decreasing. In this study, we propose the ideal strategy of the aortic surgery for the small aortic annulus. We analyzed the clinical records of 158 patients who underwent aortic valve replacement from August 1999 to October 2005 in our institution. The small aortic annulus was observed in 38 patients (24%). Fourteen patients of this group underwent ARE. Patient-prosthesis mismatch (PPM) was less frequently observed in patients with ARE compared to those without ARE. The additional time required for ARE was not considerable, and neither ischemic time nor cardiopulmonary bypass time was significantly prolonged by ARE. In conclusion, we have to select a prosthesis with sufficient orifice area to avoid PPM, otherwise we should choose an option of ARE. For this consideration, we definitely need the chart that demonstrates the relationship between the nominal size of various types of prostheses and the size of a patient's annulus that those prostheses actually fit.

  17. Pentacuspid aortic valve diagnosed by transoesophageal echocardiography

    PubMed Central

    Cemri, M; Cengel, A; Timurkaynak, T

    2000-01-01

    Congenital aortic valve anomalies are quite a rare finding in echocardiographic examinations. A case of a 19 year old man with a pentacuspid aortic valve without aortic stenosis and regurgitation, detected by transoesophageal echocardiography, is presented.


Keywords: pentacuspid aortic valve; echocardiography PMID:10995427

  18. Balloon aortic valvuloplasty as a bridge to aortic valve replacement in a patient with severe calcific aortic stenosis.

    PubMed

    Swinkels, B M; Jaarsma, W; Wely, L Relik-van; van Swieten, H A; Ernst, J M P G; Plokker, H W M

    2003-03-01

    This case report describes a patient with severe calcific aortic stenosis who was initially considered inoperable because of a very poor left ventricular function and severe pulmonary hypertension. After balloon aortic valvuloplasty, the clinical and haemodynamic status of the patient improved to such an extent that subsequent aortic valve replacement was considered possible and eventually proved to be successful. Balloon aortic valvuloplasty has value as a potential bridge to aortic valve replacement when the risks for surgery are considered to be too high.

  19. Spectral infrared hemispherical reflectance measurements for LDEF tray clamps

    NASA Technical Reports Server (NTRS)

    Wood, Bobby E.; Cromwell, Brian K.; Pender, Charles W.; Shepherd, Seth D.

    1992-01-01

    This paper describes infrared hemispherical reflectance measurements (2-15 microns) that were made on 58 chromic acid anodized tray clamps retrieved from the LDEF spacecraft. These clamps were used for maintaining the experiments in place and were located at various locations about the spacecraft. Changes in reflectance of the tray clamps at these locations were compared with atomic oxygen fluxes at the same locations. A decrease in absorption band depth was seen for the surfaces exposed to space indicating that there was some surface layer erosion. In all of the surfaces measured, little evidence of contamination was observed and none of the samples showed evidence of the brown nicotine stain that was so prominent in other experiments. Total emissivity values were calculated for both exposed and unexposed tray clamp surfaces. Only small differences, usually less than 1 percent, were observed. The spectral reflectances were measured using a hemi-ellipsoidal mirror reflectometer matched with an interferometer spectrometer. The rapid scanning capability of the interferometer allowed the reflectance measurements to be made in a timely fashion. The ellipsoidal mirror has its two foci separated by 2 inches and located on the major axis. A blackbody source was located at one focus while the tray clamp samples were located at the conjugate focus. The blackbody radiation was modulated and then focused by the ellipsoid onto the tray clamps. Radiation reflected from the tray clamp was sampled by the interferometer by viewing through a hole in the ellipsoid. A gold mirror (reflectance approximately 98 percent) was used as the reference surface.

  20. Spectral infrared hemispherical reflectance measurements for LDEF tray clamps

    NASA Technical Reports Server (NTRS)

    Wood, Bobby E.; Cromwell, Brian K.; Pender, Charles W.; Shepherd, Seth D.

    1992-01-01

    This paper describes infrared hemispherical reflectance measurements (2-15 microns) that were made on 58 chromic acid anodized tray clamps retrieved from the LDEF spacecraft. These clamps were used for maintaining the experiments in place and were located at various locations about the spacecraft. Changes in reflectance of the tray clamps at these locations were compared with atomic oxygen fluxes at the same locations. A decrease in absorption band depth was seen for the surfaces exposed to space indicating that there was some surface layer erosion. In all of the surfaces measured, little evidence of contamination was observed and none of the samples showed evidence of the brown nicotine stain that was so prominent in other experiments. Total emissivity values were calculated for both exposed and unexposed tray clamp surfaces. Only small differences, usually less than 1 percent, were observed. The spectral reflectances were measured using a hemi-ellipsoidal mirror reflectometer matched with an interferometer spectrometer. The rapid scanning capability of the interferometer allowed the reflectance measurements to be made in a timely fashion. The ellipsoidal mirror has its two foci separated by 2 inches and located on the major axis. A blackbody source was located at one focus while the tray clamp samples were located at the conjugate focus. The blackbody radiation was modulated and then focused by the ellipsoid onto the tray clamps. Radiation reflected from the tray clamp was sampled by the interferometer by viewing through a hole in the ellipsoid. A gold mirror (reflectance approximately 98 percent) was used as the reference surface.

  1. Aortic biomechanics in hypertrophic cardiomyopathy

    PubMed Central

    Badran, Hala Mahfouz; Soltan, Ghada; Faheem, Nagla; Elnoamany, Mohamed Fahmy; Tawfik, Mohamed; Yacoub, Magdi

    2015-01-01

    Background: Ventricular-vascular coupling is an important phenomenon in many cardiovascular diseases. The association between aortic mechanical dysfunction and left ventricular (LV) dysfunction is well characterized in many disease entities, but no data are available on how these changes are related in hypertrophic cardiomyopathy (HCM). Aim of the work: This study examined whether HCM alone is associated with an impaired aortic mechanical function in patients without cardiovascular risk factors and the relation of these changes, if any, to LV deformation and cardiac phenotype. Methods: 141 patients with HCM were recruited and compared to 66 age- and sex-matched healthy subjects as control group. Pulse pressure, aortic strain, stiffness and distensibility were calculated from the aortic diameters measured by M-mode echocardiography and blood pressure obtained by sphygmomanometer. Aortic wall systolic and diastolic velocities were measured using pulsed wave Doppler tissue imaging (DTI). Cardiac assessment included geometric parameters and myocardial deformation (strain and strain rate) and mechanical dyssynchrony. Results: The pulsatile change in the aortic diameter, distensibility and aortic wall systolic velocity (AWS') were significantly decreased and aortic stiffness index was increased in HCM compared to control (P < .001) In HCM AWS' was inversely correlated to age(r = − .32, P < .0001), MWT (r = − .22, P < .008), LVMI (r = − .20, P < .02), E/Ea (r = − .16, P < .03) LVOT gradient (r = − 19, P < .02) and severity of mitral regurg (r = − .18, P < .03) but not to the concealed LV deformation abnormalities or mechanical dyssynchrony. On multivariate analysis, the key determinant of aortic stiffness was LV mass index and LVOT obstruction while the role LV dysfunction in aortic stiffness is not evident in this population. Conclusion: HCM is associated with abnormal aortic mechanical properties. The severity of cardiac

  2. Thoracic endovascular aortic repair for blunt thoracic aortic injuries in complex aortic arch vessels anatomies.

    PubMed

    Piffaretti, Gabriele; Carrafiello, Gianpaolo; Ierardi, Anna Maria; Mariscalco, Giovanni; Macchi, Edoardo; Castelli, Patrizio; Tozzi, Matteo; Franchin, Marco

    2015-08-01

    The aim of this study is to report the use of thoracic endovascular aortic repair (TEVAR) in blunt thoracic aortic injuries (BTAIs) presenting with complex anatomies of the aortic arch vessels. Two patients were admitted to our hospital for the management of BTAI. Anomalies were as follow: aberrant right subclavian artery (n = 1) and right-sided aortic arch with 5 vessels anatomy variant (n = 1). TEVAR was accomplished using parallel graft with periscope configuration in the patient with the aberrant right subclavian artery. At 12-month follow-up, computed tomography angiographies confirmed the exclusion of the BTAI, the stability of the endograft, the resolution of the pseudoaneurysm, and the patency of the parallel endograft. Aortic arch vessels variants and anomalies are not rare, and should be recognized and studied precisely to plan the most appropriate operative treatment. TEVAR proved to be effective even in complex anatomies. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. Prosthesis-preserving aortic root repair after aortic valve replacement.

    PubMed

    Hamamoto, Masaki; Kobayashi, Taira; Kodama, Hiroshi

    2015-07-01

    We describe a new technique of prosthesis-preserving aortic root replacement for patients who have previously undergone aortic valve replacement. With preservation of the mechanical prosthesis, we implant a Gelweave Valsalva graft using double suture lines. The first suture line is made between the sewing cuff of the mechanical valve and the graft, with mattress sutures of 2/0 braided polyester with pledgets. After the first sutures are tied, the second suture line is created between the graft collar and the aortic root remnant with continuous 4/0 polypropylene sutures.

  4. The excluder aortic endograft.

    PubMed

    Alterman, Daniel M; Stevens, Scott L

    2008-06-01

    Since its introduction, more than 59000 patients have been treated with Gore Excluder endoprosthesis (GORE) for abdominal aortic aneurysm (AAA) in the past 11 years. It has become clearer that differences in device delivery and design provide certain advantages that may favor one anatomical milieu over another. Behavior of the aneurysm sac also seems to be graft dependent as more long-term data become available. The currently available low-permeability GORE seems to have addressed the problem of endotension noted with previous designs. Cumulative data are reviewed, and the data demonstrate very low perioperative morbidity and mortality and excellent protection from aneurysm-related complications with the GORE device. Superior ease of use, excellent trackability, and rare failures requiring acute open conversion characterize the GORE device. By addressing clinical demands of aortic endografting, Gore has eclipsed other endografts in the industry to now dominate the US market. The aim of this review is to describe the history, experience, advantages, and future goals with the GORE for the treatment of AAA.

  5. [Inflammatory abdominal aortic aneurysm].

    PubMed

    Siebenmann, R; Schneider, K; von Segesser, L; Turina, M

    1988-06-11

    348 cases of abdominal aortic aneurysm were reviewed for typical features of inflammatory aneurysm (IAAA) (marked thickening of aneurysm wall, retroperitoneal fibrosis and rigid adherence of adjacent structures). IAAA was present in 15 cases (14 male, 1 female). When compared with patients who had ordinary aneurysms, significantly more patients complained of back or abdominal pain (p less than 0.01). Erythrocyte sedimentation rate was highly elevated. Diagnosis was established in 7 of 10 computed tomographies. 2 patients underwent emergency repair for ruptured aneurysm. Unilateral ureteral obstruction was present in 4 cases and bilateral in 1. Repair of IAAA was performed by a modified technique. Histological examination revealed thickening of the aortic wall, mainly of the adventitial layer, infiltrated by plasma cells and lymphocytes. One 71-year-old patient operated on for rupture of IAAA died early, and another 78-year-old patient after 5 1/2 months. Control computed tomographies revealed spontaneous regression of inflammatory infiltration after repair. Equally, hydronephrosis due to ureteral obstruction could be shown to disappear or at least to decrease. IAAA can be diagnosed by computed tomography with high sensitivity. Repair involves low risk, but modification of technique is necessary. The etiology of IAAA remains unclear.

  6. Measuring beta-cell function relative to insulin sensitivity in youth: Does the hyperglycemic clamp suffice?

    USDA-ARS?s Scientific Manuscript database

    To compare beta-cell function relative to insulin sensitivity, disposition index (DI), calculated from two clamps (2cDI, insulin sensitivity from the hyperinsulinemic-euglycemic clamp and first-phase insulin from the hyperglycemic clamp) with the DI calculated from the hyperglycemic clamp alone (hcD...

  7. Four-dimensional magnetic resonance imaging-derived ascending aortic flow eccentricity and flow compression are linked to aneurysm morphology†

    PubMed Central

    Kari, Fabian A.; Kocher, Nadja; Beyersdorf, Friedhelm; Tscheuschler, Anke; Meffert, Philipp; Rylski, Bartosz; Siepe, Matthias; Russe, Maximilian F.; Hope, Michael D.

    2015-01-01

    OBJECTIVES The impact of specific blood flow patterns within ascending aortic and/or aortic root aneurysms on aortic morphology is unknown. We investigated the interrelation of ascending aortic flow compression/peripheralization and aneurysm morphology with respect to sinotubuar junction (STJ) definition. METHODS Thirty-one patients (aortic root/ascending aortic aneurysm >45 mm) underwent flow-sensitive 4D magnetic resonance thoracic aortic flow measurement at 3 Tesla (Siemens, Germany) at two different institutions (Freiburg, Germany, and San Francisco, CA, USA). Time-resolved image data post-processing and visualization of mid-systolic, mid-ascending aortic flow were performed using local vector fields. The Flow Compression Index (FCI) was calculated individually as a fraction of the area of high-velocity mid-systolic flow over the complete cross-sectional ascending aortic area. According to aortic aneurysm morphology, patients were grouped as (i) small root, eccentric ascending aortic aneurysm (STJ definition) and (ii) enlarged aortic root, non-eccentric ascending aortic aneurysm with diffuse root and tubular enlargement. RESULTS The mean FCI over all patients was 0.47 ± 0.5 (0.37–0.99). High levels of flow compression/peripheralization (FCI <0.6) were linked to eccentric aneurysm morphology (Group A, n = 11), while low levels or absence of aortic flow compression/peripheralization (FCI >0.8) occurred more often in Group B (n = 20). The FCI was 0.48 ± 0.05 in Group A and 0.78 ± 0.14 in Group B (P < 0.001). Distribution of bicuspid aortic valve (P = 0.6) and type of valve dysfunction (P = 0.22 for aortic stenosis) was not found to be different between groups. CONCLUSIONS Irrespective of aortic valve morphology and function, ascending aortic blood flow patterns are linked to distinct patterns of ascending aortic aneurysm morphology. Implementation of quantitative local blood flow analyses might help to improve aneurysm risk stratification in the future. PMID

  8. An Important but Forgotten Technique: Aortic Fenestration.

    PubMed

    Yalcin, Mihriban; Tayfur, Kaptan Derya; Urkmez, Melih

    2016-10-01

    Aortic fenestration is a technique that treats organ ischemia in descending aortic dissection. Open surgical aortic fenestration is an effective yet uncommonly used and widely forgotten procedure. Here, we describe 2 patients suffering from chronic thoracoabdominal aortic dissection, and we aimed to identify under what circumstances surgical aortic fenestration should be applied, to assess its safety and efficacy. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Minimally invasive aortic valve surgery

    PubMed Central

    Castrovinci, Sebastiano; Emmanuel, Sam; Moscarelli, Marco; Murana, Giacomo; Caccamo, Giuseppa; Bertolino, Emanuela Clara; Nasso, Giuseppe; Speziale, Giuseppe; Fattouch, Khalil

    2016-01-01

    Aortic valve disease is a prevalent disorder that affects approximately 2% of the general adult population. Surgical aortic valve replacement is the gold standard treatment for symptomatic patients. This treatment has demonstrably proven to be both safe and effective. Over the last few decades, in an attempt to reduce surgical trauma, different minimally invasive approaches for aortic valve replacement have been developed and are now being increasingly utilized. A narrative review of the literature was carried out to describe the surgical techniques for minimally invasive aortic valve surgery and report the results from different experienced centers. Minimally invasive aortic valve replacement is associated with low perioperative morbidity, mortality and a low conversion rate to full sternotomy. Long-term survival appears to be at least comparable to that reported for conventional full sternotomy. Minimally invasive aortic valve surgery, either with a partial upper sternotomy or a right anterior minithoracotomy provides early- and long-term benefits. Given these benefits, it may be considered the standard of care for isolated aortic valve disease. PMID:27582764

  10. [Delayed cord clamping in the interest of the newborn child].

    PubMed

    Scherjon, S A; Smit, Y

    2008-06-21

    The importance of delayed cord clamping, both for the preterm and for the term newborn, for the prevention ofneonatal anaemia (during the neonatal period and/or at the age of3 months) and furthermore to reduce the need of blood transfusions, has recently been demonstrated in controlled clinical studies and meta-analyses. Physiological and pathophysiological factors also provide a rationale for delayed cord clamping: neonatal blood volume may increase by 32% if cord clamping is delayed until the umbilical cord has completely stopped pulsating. A slow transition, involving closure of the ductus arteriosus and the foramen ovale cordis and gradual filling of the neonatal systemic circulation, contributes to the opening of the alveoli due to perfusion of the alveolar capillaries. No disadvantages, such as polycythaemia or hyperbilirubinaemia, have been described with regard to preterm neonates, whereas the incidence of intracranial haemorrhages is reduced. Also for the mother, no disadvantages of late clamping have been determined. As a standard procedure, the baby's umbilical cord should not be clamped until at least 3 minutes have passed. One should wait at least 30 seconds during the birth of children for whom a more active approach is necessary. Of all people, these children will benefit from a good Hb level.

  11. Dynamic Clamp in Cardiac and Neuronal Systems Using RTXI

    PubMed Central

    Ortega, Francis A.; Butera, Robert J.; Christini, David J.; White, John A.; Dorval, Alan D.

    2016-01-01

    The injection of computer-simulated conductances through the dynamic clamp technique has allowed researchers to probe the intercellular and intracellular dynamics of cardiac and neuronal systems with great precision. By coupling computational models to biological systems, dynamic clamp has become a proven tool in electrophysiology with many applications, such as generating hybrid networks in neurons or simulating channelopathies in cardiomyocytes. While its applications are broad, the approach is straightforward: synthesizing traditional patch clamp, computational modeling, and closed-loop feedback control to simulate a cellular conductance. Here, we present two example applications: artificial blocking of the inward rectifier potassium current in a cardiomyocyte and coupling of a biological neuron to a virtual neuron through a virtual synapse. The design and implementation of the necessary software to administer these dynamic clamp experiments can be difficult. In this chapter, we provide an overview of designing and implementing a dynamic clamp experiment using the Real-Time eXperiment Interface (RTXI), an open- source software system tailored for real-time biological experiments. We present two ways to achieve this using RTXI’s modular format, through the creation of a custom user-made module and through existing modules found in RTXI’s online library. PMID:25023319

  12. Automated ion channel screening: patch clamping made easy.

    PubMed

    Farre, Cecilia; Stoelzle, Sonja; Haarmann, Claudia; George, Michael; Brüggemann, Andrea; Fertig, Niels

    2007-04-01

    Efficient high resolution techniques are required for screening efforts and research targeting ion channels. The conventional patch clamp technique, a high resolution but low efficiency technique, has been established for 25 years. Recent advances have opened up new possibilities for automated patch clamping. This new technology meets the need of drug developers for higher throughput and facilitates new experimental approaches in ion channel research. Specifically, Nanion's electrophysiology workstations, the Port-a-Patch and the Patchliner, have been successfully introduced as high-quality automated patch clamp platforms for industry as well as academic users. Both platforms give high quality patch clamp recordings, capable of true giga-seals and stable recordings, accessible to the user without the need for years of practical training. They also offer sophisticated experimental possibilities, such as accurate and fast ligand application, temperature control and internal solution exchange. This article describes the chip-based patch clamp technology and its usefulness in ion channel drug screening and academic research.

  13. Axon voltage-clamp simulations. I. Methods and tests.

    PubMed Central

    Moore, J W; Ramón, F; Joyner, R W

    1975-01-01

    This is the first in a series of four papers in which we present the numerical simulation of the application of the voltage clamp technique to excitable cells. In this paper we describe the application of the Crank-Nicolson (1947) method for the solution of the parabolic partial differential equations that describe a cylindrical cell in which the ionic conductances are functions of voltage and time (Hodgkin and Huxley, 1952). This method is compared with other methods in terms of accuracy and speed of solution for a propagated action potential. In addition, differential equations representing a simple voltage-clamp electronic circuit are presented. Using the voltage clamp circuit equations, we simulate the voltage clamp of a single isopotential membrane patch and show how the parameters of the circuit affect the transient response of the patch to a step change in the control potential.The stimulation methods presented in this series of papers allow the evaluation of voltage clamp control of an excitable cell or a syncytium of excitable cells. To the extent that membrane parameters and geometrical factors can be determined, the methods presented here provide solutions for the voltage profile as a function of time. PMID:1174640

  14. Targeted Endovascular Temporary Vessel Occlusion with a Reverse Thermosensitive Polymer for Near-Bloodless Partial Nephrectomy: Comparison to Standard Surgical Clamping Techniques

    SciTech Connect

    Flacke, Sebastian; Harty, Niall J.; Laskey, Daniel H.; Moinzadeh, Alireza; Benn, James A.; Villani, Rosanna; Kalra, Aarti; Libertino, John A.; Madras, Peter N.

    2012-10-15

    Purpose: To determine whether reversible blood flow interruption to a randomly chosen target region of the kidney may be achieved with the injection of a reverse thermoplastic polymer through an angiographic catheter, thereby facilitating partial nephrectomy without compromising blood flow to the remaining kidney or adding risks beyond those encountered by the use of hilar clamping. Methods: Fifteen pigs underwent partial nephrectomy after blood flow interruption by vascular cross-clamping or injection of polymer (Lumagel Trade-Mark-Sign ) into a segmental artery. Five animals were euthanized after surgery (three open and two laparoscopic resection, cross-clamping n = 2), and 10 (open resection, cross-clamping n = 4) were euthanized after 6 weeks' survival. Blood specimens were obtained periodically, and angiogram and necropsy were performed at 6 weeks. Results: Selective renal ischemia was achieved in all cases. Surgical resection time averaged 9 and 24.5 min in the open and laparoscopic groups, respectively. Estimated blood loss was negligible with the exception of one case where an accessory renal artery was originally overlooked. Reversal of the polymer to a liquid state was consistent angiographically and visually in all cases. Time to complete flow return averaged 7.4 and 2 min for polymer and clamping, respectively. Angiography at 6 weeks revealed no evidence of vascular injury. Laboratory data and necropsies revealed no differences between animals undergoing vascular clamping or polymer injection. Conclusion: Lumagel was as effective as vascular clamping in producing a near bloodless operative field for partial nephrectomy while maintaining flow to the uninvolved portion of the affected kidney.

  15. Effect of sterilization on stiffness and dimensional stability of rubber-dam clamps.

    PubMed

    Giebink, D L; Mathieu, G P; Hondrum, S O

    1996-01-01

    Simulated clinical conditions were used to test the effect of sterilization on rubber-dam clamp stiffness and dimension. Sixty Hygienic and Ivory W7 clamps were either steam or dry heat sterilized and compared to controls. Stiffness and dimensional change between Ivory clamp groups was significant (p<.0001); the sterilized clamps showed less change than the controls. Hygienic groups showed a significant different between the control and dry heat groups (p<.05); the sterilized clamps showed less change than the controls. The change in stiffness and interjaw width for all Ivory clamps compared to all Hygienic clamps was significant (p<.0001). The Hygienic clamps changes less than the Ivory clamps. The results indicate that steam and dry heat sterilization do not affect retention of rubber-dam clamps.

  16. High aortic pulse-wave velocity may be responsible for elevated red blood cell distribution width in overweight and obese people: a community-based, cross-sectional study

    PubMed Central

    Altiparmak, Ibrahim Halil; Erkus, Muslihittin Emre; Gunebakmaz, Ozgur; Yusuf, Sezen; Zekeriya, Kaya; Demirbag, Recep; Kocarslan, Aydemir; Sezen, Hatice; Yildiz, Ali

    2016-01-01

    Summary Background: Obesity and overweight are risk factors for atherosclerosis. Red blood cell distribution width (RDW) is associated with subclinical cardiac diseases. The aim of this study was to investigate the association between RDW and aortic stiffness in overweight or obese subjects. Methods: A total of 101 overweight or obese subjects without overt cardiovascular disorders, and 48 healthy controls were enrolled. RDW, aortic pulse-wave velocity (PWV) and augmentation index 75 (Aix75) were evaluated. The case subjects were divided into two sub-groups according to PWV values; ≥ 10 m/s in group I, and < 10 m/s in group II. Bivariate correlation and multiple regression analyses (stepwise) were performed. Results RDW and PWV were considerably increased in the case groups compared with the controls. RDW was significantly increased in group I compared with group II and the controls [median 12.0 m/s, interquartile range (IQR): 10.5–17.5; median 11.7 m/s, IQR: 10.2–14.2, and median 11.4 m/s, IQR: 9.6–15.5, p < 0.05, respectively]. Resting heart rate and age were higher in group I than group II (81 ± 11 vs 74 ± 12 beats/min and 41 ± 120 vs 36 ± 9 years, respectively, p < 0.05). Regression analyses revealed that while log-RDW, age and resting heart rate were independent predictors for aortic PWV, log-RDW was the most important predictor in the final model. Conclusions: RDW, resting heart rate and age independently predicted arterial stiffness, and RDW may be useful to provide an early recognition of subclinical atherosclerosis in overweight and obese individuals. PMID:26895298

  17. Aortic pulsatility assessed by an oscillometric method is associated with coronary atherosclerosis in elderly people.

    PubMed

    Nakagomi, Atsushi; Okada, Sho; Shoji, Toshihiro; Kobayashi, Yoshio

    2016-12-01

    The aim of this study was to investigate the association of aortic pulsatility assessed by a non-invasive brachial cuff-based method with coronary atherosclerosis. In total, 139 patients undergoing coronary angiography were included in this cross-sectional study. Aortic blood pressure (BP) indices were recorded invasively by a fluid-filled catheter and non-invasively by a brachial cuff-based oscillometric device. Fractional pulse pressure (FPP) was defined as pulse pressure (PP)/mean BP and pulsatility index (PI) as PP/diastolic BP. Aortic FPP and PI in coronary artery disease (CAD) patients were significantly higher than in non-CAD patients in both invasive and non-invasive methods. Multivariate logistic regression analysis demonstrated that non-invasively measured aortic FPP and PI were associated with CAD risk in patients aged ≥70 years [aortic FPP per 0.1 odds ratio (OR) = 1.66, 95% confidence interval (CI) 1.05-2.64; aortic PI per 0.1 OR =1.39, 95% CI 1.02-1.88; all p < 0.05], but were not associated with CAD risk in patients aged <70 years. In linear regression analysis, non-invasively measured aortic FPP and PI correlated with SYNTAX and Gensini scores only in patients aged ≥70 years. Aortic FPP and PI measured non-invasively by a brachial cuff-based oscillometric device were associated with coronary atherosclerosis in elderly patients.

  18. Total aortic arch replacement with frozen elephant trunk in acute type A aortic dissections: are we pushing the limits too far?†.

    PubMed

    Shrestha, Malakh; Fleissner, Felix; Ius, Fabio; Koigeldiyev, Nurbol; Kaufeld, Tim; Beckmann, Erik; Martens, Andreas; Haverich, Axel

    2015-02-01

    Acute type A aortic dissection (AADA) is a surgical emergency. In patients with aortic arch and descending aorta (DeBakey type I) involvement, performing a total aortic arch replacement with frozen elephant trunk (FET) for supposedly better long-term results is controversial. We hereby present our results. From February 2004 to August 2013, 52 patients with acute aortic dissection DeBakey type I received a FET procedure at our centre (43 males, age 59.21 ± 11.67 years). All patients had an intimal tear in the aortic arch and/or proximal descending aorta. Concomitant procedures were Bentall (n = 15) and aortic valve repair (n = 30). Cardiopulmonary bypass (CPB), X-clamp and cardiac arrest times were 262 ± 64, 159 ± 45 and 55 ± 24 min, respectively. The 30-day mortality rate was 13% (n = 7). Stroke and re-thoracotomy for bleeding were 12% (n = 6) and 23% (n = 12), respectively. Postoperative recurrent nerve palsy and spinal cord injury rates were 10% (5 of 52) and 4% (2 of 52), respectively. Follow-up was 40 ± 24 months. During follow-up, no patient died and no patient required a reoperation for the aortic arch. Our results with FET in AADA show acceptable results. Total aortic arch replacement with an FET in AADA patients does demand high technical skills. In spite of this, we believe FET improves long-term outcomes in cases of AADA with intima tear or re-entry in the aortic arch or the descending aorta (DeBakey type I). Modern grafts with four side branches as well as sewing collars for the distal anastomosis have helped to further 'simplify' the FET implantation. However, such a strategy is not appropriate in all AADA cases; it should be implemented only in experienced centres and only if absolutely necessary. © The Author 2014. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  19. Is cold blood cardioplegia absolutely superior to cold crystalloid cardioplegia in aortic valve surgery?

    PubMed

    Lerman, Daniel A; Otero-Losada, Matilde; Ume, Kiddy; Salgado, Pablo A; Prasad, Sai; Lim, Kelvin; Péault, Bruno; Alotti, Nasri

    2017-05-26

    Experimental evidence suggests that blood cardioplegia (BCP) may be superior to cold crystalloid cardioplegia (CCP) for myocardial protection. However, robust clinical data are lacking. We compared post-operative outcome of patients undergoing aortic valve replacement (AVR) using cold anterograde-retrograde intermittent BCP versus anterograde (CCP). Adult consecutive isolated AVR performed between April 2006 and February 2011 at the Royal Infirmary Hospital of Edinburgh were retrospectively analyzed. The use of anterograde CCP was compared with that of intermittent anterograde-retrograde cold BCP. End points were intra-operative mortality, 30-day hospital re-admission, need for RBC or platelet transfusion, mechanical ventilation time and renal failure. Of total 774 cases analyzed, 592 cases of BCP and 182 cases of CCP were identified. Demographics did not differ between groups (mean patient age in years): 67±12 CCP and 69±12 BCP. Groups (BCP vs CCP) were indistinguishable (p > 0.05, NS) based on: average aortic cross clamp time (min) 77.01±14.47 vs 75.78±18.78, cardiopulmonary bypass time (min) 104.07±43.70 vs 100.34±25.90, surgery time (min) 190.53±61.80 vs 204.04±51.09 and post-operative total blood consumption (units) 1.38±2.11 vs 1.61±2.4. The percentage of patients who required platelets' transfusion was similar: 12.8% BCP and 18.7% CCP (Fisher exact test, p=0.053). Prevalence of respiratory failure was lower in BCP than in CCP: 2.6% vs 6.3% (p=0.028). Admission time (days) at ICU was 3.63± 21.90 in BCP and 3.07 ± 8.04 in CCP (NS). Intra-hospital mortality, 30-day hospital re-admission, renal failure, sepsis, wound healing and stroke did not differ between groups. BCP was strictly not superior to CCP in every aspect. In particular it was definitely not superior in terms of post-operative ventricular function. Our results question the absolute superiority of BCP over CCP in terms of hard outcomes. Likelihood of serious complications should be

  20. Umbilical cord clamping. An analysis of a usual neonatological conduct.

    PubMed

    Papagno, L

    1998-01-01

    Here we described a critical analysis of the neonatological procedure of early cord clamping, meaning this, within 40 seconds after birth. Fifty three cases are here analysed, in which this practice was not performed, but instead a late umbilical cord clamping was done after birth or after the cord had stopped beating. Variations in hematocrito values within 24 to 36 hours after birth were studied. A transitory polycithemia, with a maximum peak 12 hours post-delivery was observed. These values returned to normal levels between 24 and 36 hours after birth. K vitamin was not administered to any of the newborns. No pathology appeared related to this transitory polycithemia. In can be concluded that the late umbilical cord clamping represents no risk to the new-born and that the pathological phenomena described under these circumstances may be attributed to the increase in K vitamin dependent coagulation factors that are induced by the routinary administration of phitonadione to all normal newborns.

  1. Using physiology to guide time to cord clamping.

    PubMed

    Kluckow, Martin; Hooper, Stuart B

    2015-08-01

    Immediate clamping and cutting of the umbilical cord at birth has been the accepted standard of care for decades. The physiologic rationale relating umbilical cord clamping (UCC) to the events of the circulatory transition is not considered in arbitrarily recommended cord clamping times. Systematic review of early versus deferred UCC shows significant hemodynamic benefits to the deferred group. Mechanisms for this protective effect are considered in this review. The original concept of a placental transfusion with a volume load and prevention of low cardiac output relies on the physiological end point of the amount of blood transfused. The newer concept of an ordered physiological transition is increasingly supported. This model places aeration of the lungs and an increase in pulmonary blood flow back at the centre of the circulatory transition with timing of UCC being related to establishment of respiration. The need for "physiologically based" UCC is discussed. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

  2. [Advantage of delayed umbilical cord clamping in the newborn infant].

    PubMed

    Menget, A; Mougey, C; Thiriez, G; Riethmuller, D

    2013-09-01

    The timing of umbilical cord clamping remains controversial. Although most maternity wards use the early clamping (5-15s), randomized studies and meta-analyses have demonstrated the benefit of delayed clamping for term and preterm newborn infants over the past 10 years. Indeed, placentofetal transfusion of 20-30 ml/kg in 2-3 min improves the iron status of term infants and prevents infant hypochromic anemia. Infant anemia is a public health problem in many developing countries. For preterm newborns, placental transfusion for 45 s or milking the cord for 15 s improves cardiovascular adaptation, with better hemodynamic stability, as well as decreased intraventricular hemorrhages, need for transfusion, and late-onset sepsis. A new look at this symbolic act is needed and professionals need to be persuaded of the importance of the "wait a minute" policy for a better physiological delivery.

  3. Timing of clamping and factors associated with iron stores in full-term newborns

    PubMed Central

    Oliveira, Fabiana de Cássia Carvalho; Assis, Karine Franklin; Martins, Mariana Campos; do Prado, Mara Rúbia Maciel Cardoso; Ribeiro, Andréia Queiroz; Sant’Ana, Luciana Ferreira da Rocha; Priore, Silvia Eloiza; Franceschini, Sylvia do Carmo Castro

    2014-01-01

    OBJECTIVE To analyze the impact of timing of clamping and obstetric, biological and socioeconomic factors on the iron stores of full-term newborns. METHODS Cross-sectional study between October 2011 and July 2012 in which hematological parameters were evaluated for newborns in Viçosa, MG, Southeastern Brazil. It involved collecting 7 mL of umbilical cord blood from 144 full-term not underweight newborns. The parameters investigated were complete blood count, serum iron, ferritin and C-reactive protein. The time of umbilical cord clamping was measured using a digital timer without interfering in the procedures of childbirth. The birth data were collected from Live Birth Certificates and other information was obtained from the mother through a questionnaire applied in the first month postpartum. Analysis of multiple linear regression was then used to estimate the influence of biological, obstetrics and socioeconomic factors on the ferritin levels at birth. RESULTS The median ferritin was 130.3 µg/L (n = 129, minimum = 16.4; maximum = 420.5 µg/L), the mean serum iron was 137.9 μg/dL (n = 144, SD = 39.29) and mean hemoglobin was 14.7 g/dL (n = 144, SD = 1.47). The median time of cord clamping was 36 seconds, ranging between 7 and 100. The bivariate analysis detected an association between ferritin levels and color of the child, timing clamping of 60 seconds, type of delivery, the presence of gestational diabetes and per capita family income. In multivariate analysis, the variables per capita income, number of antenatal visits and length at birth accounted for 22.0% of variation in ferritin levels. CONCLUSIONS Iron stores at birth were influenced by biological, obstetric and social characteristics. Tackling anemia should involve creating policies aimed at reducing social inequalities, improving the quality of antenatal care, as well as implementing a criterion of delayed clamping of the umbilical cord within the guidelines of labor. PMID:24789632

  4. GenTAC Registry Report: Gender Differences Among Individuals with Genetically-Triggered Thoracic Aortic Aneurysm and Dissection

    PubMed Central

    Holmes, Kathryn W.; Maslen, Cheryl L.; Kindem, Mark; Kroner, Barbara L.; Song, Howard K.; Ravekes, William; Dietz, H.C.; Weinsaft, Jonathan W.; Roman, Mary J.; Devereux, Richard B.; Pyeritz, Reed E.; Bavaria, Joseph; Milewski, Karianna; Milewicz, Dianna; LeMaire, Scott A.; Hendershot, Tabitha; Eagle, Kim A.; Tolunay, H. Eser; Desvigne-Nickens, Patrice; Silberbach, Michael

    2013-01-01

    Previous data suggest women are at increased risk of death from aortic dissection. Therefore, we analyzed data from the GenTAC registry, the NIH-sponsored program that collects information about individuals with genetically-triggered thoracic aortic aneurysms and cardiovascular conditions. We performed cross-sectional analyses in adults with Marfan syndrome (MFS), familial thoracic aortic aneurysm or dissection (FTAAD), bicuspid aortic valve (BAV) with thoracic aortic aneurysm or dissection, and subjects under 50 years of age with thoracic aortic aneurysm or dissection (TAAD<50y). Women comprised 32% of 1449 subjects and were 21% of subjects with BAV, 34% with FTAAD, 22% with TAAD <50y, and 47% with MFS. Thoracic aortic dissections occurred with equal gender frequency yet women with BAV had more extensive dissections. Aortic size was smaller in women but was similar after controlling for BSA. Age at operation for aortic valve dysfunction, aneurysm or dissection did not differ by gender. Multivariate analysis (adjusting for age, BSA, hypertension, study site, diabetes, and subgroup diagnoses) showed that women had fewer total aortic surgeries (OR= 0.65, p < 0.01) and were less likely to receive angiotensin converting enzyme inhibitors (ACEi) (OR=0.68, p < 0.05). As in BAV, other genetically-triggered aortic diseases such as FTAAD and TAAD<50 are more common in males. In women, decreased prevalence of aortic operations and less treatment with ACEi may be due to their smaller absolute aortic diameters. Longitudinal studies are needed to determine if women are at higher risk for adverse events. PMID:23444191

  5. Plasma temperature clamping in filamentation laser induced breakdown spectroscopy

    SciTech Connect

    Harilal, Sivanandan S.; Yeak, J.; Phillips, Mark C.

    2015-10-19

    Ultrafast laser filament induced breakdown spectroscopy is a very promising method for remote material detection. We present characteristics of plasmas generated in a metal target by laser filaments in air. Our measurements show that the temperature of the ablation plasma is clamped along the filamentation channel due to intensity clamping in a filament. Nevertheless, significant changes in radiation intensity are noticeable, and this is essentially due to variation in the number density of emitting atoms. The present results also partly explains the reason for the occurrence of atomic plume during fs LIBS in air compared to long-pulse ns LIBS.

  6. Contained Rupture of an Abdominal Aortic Aneurysm With Extensive Vertebral Body and Retroperitoneal Space Destruction.

    PubMed

    Walker, Sean T; Pipinos, Iraklis I; Johanning, Jason M; Vargo, Christopher J

    Chronic contained rupture of an abdominal aortic aneurysm with vertebral body erosion most commonly presents with symptoms of low back pain. Although not well known, vertebral body erosion or destruction may be seen in up to 25% of patients with sealed or contained rupture of an abdominal aortic aneurysm. This appearance on cross-sectional imaging may mimic a malignant or infectious process. Although these cases can present a diagnostic challenge, published cases of chronic contained rupture of an abdominal aortic aneurysm with vertebral body erosion demonstrate clinical and imaging similarities that, when recognized, can assist in diagnosis.

  7. Abdominal aortic aneurysm repair - open

    MedlinePlus

    AAA - open; Repair - aortic aneurysm - open ... Open surgery to repair an AAA is sometimes done as an emergency procedure when there is bleeding inside your body from the aneurysm. You may have an ...

  8. Screening for Abdominal Aortic Aneurysm

    MedlinePlus

    ... signs or symptoms of an abdominal aortic aneurysm (AAA). The final recommendation statement summarizes what the Task ... the potential benefits and harms of screening for AAA: (1) Men ages 65 to 75 who smoke ...

  9. Misconceptions and Facts About Aortic Stenosis.

    PubMed

    Argulian, Edgar; Windecker, Stephan; Messerli, Franz H

    2017-04-01

    Aortic stenosis is the most common valvular heart disease leading to intervention, and it is typically a disease of the elderly. Recent clinical advances have expanded the role of transcatheter aortic valve intervention in patients with severe aortic stenosis, making aortic valve intervention feasible and effective even in patients at intermediate, high, and prohibitive surgical risk. With the rapid advances in treatment, proper diagnosis becomes crucial for a wide range of patients with aortic stenosis: from "concordant" high-gradient aortic stenosis to "discordant" low-gradient aortic stenosis. The latter group commonly presents a clinical challenge requiring thoughtful and comprehensive evaluation to determine eligibility for aortic valve intervention. Providers at all levels should be familiar with basic diagnostic caveats and misconceptions when evaluating patients with possible aortic stenosis. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. [New aspects in aortic valve disease].

    PubMed

    Tornos, P

    2001-01-01

    Renewed interest for aortic valve disease has evolved in recent years. Aortic valve replacement has become the second most frequent cause of cardiac surgery, following coronary bypass surgery. In addition, the etiologic and physiopathologic knowledge of this disorder has improved. In the present paper we analyze three aspects of the disease which are, at present, the subject of study and controversy: first, we discuss the possible relationship between degenerative aortic stenosis and atherosclerosis; second, the involvement of the aortic root in cases of bicuspid aortic valve; and third, the surgical indications in asymptomatic patients with either aortic stenosis or regurgitation.

  11. 21 CFR 882.5175 - Carotid artery clamp.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Carotid artery clamp. 882.5175 Section 882.5175 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... (the principal artery in the neck that supplies blood to the brain) and has a removable...

  12. 21 CFR 882.5175 - Carotid artery clamp.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Carotid artery clamp. 882.5175 Section 882.5175 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... (the principal artery in the neck that supplies blood to the brain) and has a removable adjusting...

  13. 21 CFR 882.5175 - Carotid artery clamp.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Carotid artery clamp. 882.5175 Section 882.5175 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... (the principal artery in the neck that supplies blood to the brain) and has a removable adjusting...

  14. 21 CFR 882.5175 - Carotid artery clamp.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Carotid artery clamp. 882.5175 Section 882.5175 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... (the principal artery in the neck that supplies blood to the brain) and has a removable adjusting...

  15. 21 CFR 882.5175 - Carotid artery clamp.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Carotid artery clamp. 882.5175 Section 882.5175 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... (the principal artery in the neck that supplies blood to the brain) and has a removable adjusting...

  16. Clamp provides efficient connection for high-density currents

    NASA Technical Reports Server (NTRS)

    Mc Carthy, J. R.; Trebes, D. M.

    1967-01-01

    Electrical connector clamp /bus bar/ gives high contact-surface efficiency for providing a high current to thin wall stainless steel tubing containing hydrogen gas. It uses lead solder film to provide the electrical equivalent of a fusion bond without degrading the grain structure, permitting disassembly and reuse of the components.

  17. 30 CFR 18.40 - Cable clamps and grips.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Cable clamps and grips. 18.40 Section 18.40 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS ELECTRIC MOTOR-DRIVEN MINE EQUIPMENT AND ACCESSORIES Construction and Design...

  18. 30 CFR 18.40 - Cable clamps and grips.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Cable clamps and grips. 18.40 Section 18.40 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS ELECTRIC MOTOR-DRIVEN MINE EQUIPMENT AND ACCESSORIES Construction and Design...

  19. Do not overlook an umbilical cord hernia before clamping.

    PubMed

    Cizmeci, Mehmet Nevzat; Kanburoglu, Mehmet Kenan; Akelma, Ahmet Zulfikar; Tatli, Mustafa Mansur

    2013-08-01

    An umbilical cord hernia is a rare midline abdominal defect. These masses may be easily overlooked at birth, which may result in an intestinal injury due to careless proximal application of the cord clamp. Herein, we present a newborn infant with an umbilical cord hernia who was managed by primary closure of the lesion.

  20. Beyond the patch clamp: nanotechnologies for intracellular recording.

    PubMed

    Kruskal, Peter B; Jiang, Zhe; Gao, Teng; Lieber, Charles M

    2015-04-08

    The patch clamp is a fundamental tool for neuroscientists, offering insights that have shaped our understanding of the brain. Advances in nanotechnology suggest that the next generation of recording methods is now within reach. We discuss the complexity and future promise of applying nanoscience to neural recording. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. Robotic partial nephrectomy with selective parenchymal compression (Simon clamp).

    PubMed

    Castillo, O A; Rodriguez-Carlin, A; Lopez-Fontana, G; Aleman, E

    2013-01-01

    To present our initial experience using selective renal parenchymal ischemia, without hilar clamping, in robotic-assisted partial nephrectomy. In four patients with T1a renal tumor we performed robotic-assisted partial nephrectomy, using the Simon's clamp (Aesculap). It provides selective parenchymal compression without the need of vascular clamping. All patients had exofitic renal tumors in polar location. Renal parenchymal reconstruction was done as the standard technique. The median age was 49.6 years (42-59), 3 male and 1 female patient. Median operative time was 71,6 minutes (40-120). Mean stimated bleeding was 250 ml (50-400). Average tumor size was 3,25 cm (1,5-5,3). There were no complications and the average hospital stay was 3,5 days (1-7). The pathology was informed as renal cell carcinoma in three patients and one hemorrhagic cyst. The surgical margins were negative. Our preliminary results shows that selective renal parenchymal compression, with the Simon's clamp, provides an alternative to vascular control in selected patients with polar renal tumors. Copyright © 2012 AEU. Published by Elsevier Espana. All rights reserved.

  2. A band clamp with a spring toggle lever

    NASA Technical Reports Server (NTRS)

    Simmonds, M.

    1974-01-01

    Clamp could have several applications, as it provides tolerance for both expansion and contraction. It might be useful with firemen's breathing apparatus and luggage racks and other freight-carrying equipment. Also, using same piece as handle and spring reduces production costs by reducing number of parts.

  3. Robotic total endoscopic sutureless aortic valve replacement: proof of concept for a future surgical setting.

    PubMed

    Vola, Marco; Maureira, Pablo; Kassir, Radwan; Fuzellier, Jean-François; Campisi, Salvatore; Doguet, Fabien; Albertini, Jean-Noel; Ruggieri, Vito Giovanni; Folliguet, Thierry

    2016-09-01

    Sutureless valves have recently enabled closed chest aortic valve replacement. This paper evaluates the feasibility of a robotic telemanipulation during thoracoscopic sutureless aortic valve implantation in cadavers. Cadavers were prepared with a five thoracosopic trocar setting, with a transthoracic clamp inserted in the first right intercostal space and the optics inserted in the second. Seven sutureless valve implantations were scheduled using 5 Sorin Perceval and 2 Medtronic 3f Enable valves. In all cases performance of pericardial suspension, aortotomy and root exposure required less than 20 min. Native valve excision and sutureless bioprosthesis implantation was technically feasible in all cases. A satisfactory prosthesis sealing was ascertained visually and the absence of paravalvular leakages was assessed with a nerve hook test around the prosthetic flange. Closed chest and robot assisted sutureless valve implantation is feasible in cadavers. Robotic technology can enhance reproducibility of the technique. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

  4. Rare or unusual causes of chronic, isolated, pure aortic regurgitation

    SciTech Connect

    Waller, B.F.; Taliercio, C.P.; Dickos, D.K.; Howard, J.; Adlam, J.H.; Jolly, W. )

    1990-08-01

    Six patients undergoing aortic valve replacement had rare or unusual causes of isolated, pure aortic regurgitation. Two patients had congenitally bicuspid aortic valves with a false commissure (raphe) displaced to the aortic wall (tethered bicuspid aortic valve), two had floppy aortic valves, one had a congenital quadricuspid valve, and one had radiation-induced valve damage.

  5. An improved vaseline gap voltage clamp for skeletal muscle fibers

    PubMed Central

    1976-01-01

    A Vaseline gap potentiometric recording and voltage clamp method is developed for frog skeletal muscle fibers. The method is based on the Frankenhaeuser-Dodge voltage clamp for myelinated nerve with modifications to improve the frequency response, to compensate for external series resistance, and to compensate for the complex impedance of the current-passing pathway. Fragments of single muscle fibers are plucked from the semitendinosus muscle and mounted while depolarized by a solution like CsF. After Vaseline seals are formed between fluid pools, the fiber ends are cut once again, the central region is rinsed with Ringer solution, and the feedback amplifiers are turned on. Errors in the potential and current records are assessed by direct measurements with microelectrodes. The passive properties of the preparation are simulated by the "disk" equivalent circuit for the transverse tubular system and the derived parameters are similar to previous measurements with microelectrodes. Action potentials at 5 degrees C are long because of the absence of delayed rectification. Their shape is approximately simulated by solving the disk model with sodium permeability in the surface and tubular membranes. Voltage clamp currents consist primarily of capacity currents and sodium currents. The peak inward sodium current density at 5 degrees C is 3.7 mA/cm2. At 5 degrees C the sodium currents are smoothly graded with increasing depolarization and free of notches suggesting good control of the surface membrane. At higher temperatures a small, late extra inward current appears for small depolarizations that has the properties expected for excitation in the transverse tubular system. Comparison of recorded currents with simulations shows that while the transverse tubular system has regenerative sodium currents, they are too small to make important errors in the total current recorded at the surface under voltage clamp at low temperature. The tubules are definitely not under voltage

  6. Rediscovering sperm ion channels with the patch-clamp technique

    PubMed Central

    Kirichok, Yuriy; Lishko, Polina V.

    2011-01-01

    Upon ejaculation, mammalian spermatozoa have to undergo a sequence of physiological transformations within the female reproductive tract that will allow them to reach and fertilize the egg. These include initiation of motility, hyperactivation of motility and perhaps chemotaxis toward the egg, and culminate in the acrosome reaction that permits sperm to penetrate the protective vestments of the egg. These physiological responses are triggered through the activation of sperm ion channels that cause elevations of sperm intracellular pH and Ca2+ in response to certain cues within the female reproductive tract. Despite their key role in sperm physiology and their absolute requirement for the process of fertilization, sperm ion channels remain poorly understood due to the extreme difficulty in application of the patch-clamp technique to spermatozoa. This review covers the topic of sperm ion channels in the following order: first, we discuss how the intracellular Ca2+ and pH signaling mediated by sperm ion channels controls sperm behavior during the process of fertilization. Then, we briefly cover the history of the methodology to study sperm ion channels, which culminated in the recent development of a reproducible whole-cell patch-clamp technique for mouse and human cells. We further discuss the main approaches used to patch-clamp mature mouse and human spermatozoa. Finally, we focus on the newly discovered sperm ion channels CatSper, KSper (Slo3) and HSper (Hv1), identified by the sperm patch-clamp technique. We conclude that the patch-clamp technique has markedly improved and shifted our understanding of the sperm ion channels, in addition to revealing significant species-specific differences in these channels. This method is critical for identification of the molecular mechanisms that control sperm behavior within the female reproductive tract and make fertilization possible. PMID:21642646

  7. Clamped-filament elongation model for actin-based motors.

    PubMed Central

    Dickinson, Richard B; Purich, Daniel L

    2002-01-01

    Although actin-based motility drives cell crawling and intracellular locomotion of organelles and certain pathogens, the underlying mechanism of force generation remains a mystery. Recent experiments demonstrated that Listeria exhibit episodes of 5.4-nm stepwise motion corresponding to the periodicity of the actin filament subunits, and extremely small positional fluctuations during the intermittent pauses [S. C. Kuo and J. L. McGrath. 2000. Nature. 407:1026-1029]. These findings suggest that motile bacteria remain firmly bound to actin filament ends as they elongate, a behavior that appears to rule out previous models for actin-based motility. We propose and analyze a new mechanochemical model (called the "Lock, Load & Fire" mechanism) for force generation by means of affinity-modulated, clamped-filament elongation. During the locking step, the filament's terminal ATP-containing subunit binds tightly to a clamp situated on the surface of a motile object; in the loading step, actin.ATP monomer(s) bind to the filament end, an event that triggers the firing step, wherein ATP hydrolysis on the clamped subunit attenuates the filament's affinity for the clamp. This last step initiates translocation of the new ATP-containing terminus to the clamp, whereupon another cycle begins anew. This model explains how surface-tethered filaments can grow while exerting flexural or tensile force on the motile surface. Moreover, stochastic simulations of the model reproduce the signature motions of Listeria. This elongation motor, which we term actoclampin, exploits actin's intrinsic ATPase activity to provide a simple, high-fidelity enzymatic reaction cycle for force production that does not require elongating filaments to dissociate from the motile surface. This mechanism may operate whenever actin polymerization is called upon to generate the forces that drive cell crawling or intracellular organelle motility. PMID:11806905

  8. Polarization states and dielectric responses of elastically clamped ferroelectric nanocrystals

    NASA Astrophysics Data System (ADS)

    Azovtsev, A. V.; Pertsev, N. A.

    2016-12-01

    Polarization states and physical properties of ferroelectrics depend on the mechanical boundary conditions due to electrostrictive coupling between electric polarization and lattice strains. Here, we describe theoretically both equilibrium thermodynamic states and electric permittivities of ferroelectric nanocrystals subjected to the elastic three-dimensional (3D) clamping by a surrounding dielectric material. The problem is solved by the minimization of a special thermodynamic potential that describes the case of an ellipsoidal ferroelectric inclusion embedded into a linear elastic matrix. Numerical calculations are performed for BaTiO3, PbTiO3, and Pb(Zr0.5Ti0.5)O3 nanoparticles surrounded by silica glass. It is shown that, in the case of BaTiO3 and PbTiO3, elastic 3D clamping may change the order of a ferroelectric phase transition from first to second. Furthermore, the mechanical inclusion-matrix interaction shifts the temperatures of structural transitions between different ferroelectric states and even eliminates some ferroelectric phases existing in stress-free BaTiO3 and Pb(Zr0.5Ti0.5)O3 crystals. Another important effect of elastic clamping is the lowering of the symmetry of ferroelectric states in ellipsoidal inclusions, where orthorhombic and monoclinic phases may form instead of the tetragonal and rhombohedral bulk counterparts. Finally, our thermodynamic calculations show that the dielectric responses of studied perovskite ferroelectrics are sensitive to matrix-induced clamping as well. For instance, dielectric peaks occurring at structural transitions between different ferroelectric phases in BaTiO3 appear to be much higher in spherical inclusions than in the freestanding crystal. Predicted clamping-induced enhancement of certain dielectric responses at room temperature indicates that composite materials comprising nanocrystals of perovskite ferroelectrics are promising for device applications requiring the use of high-permittivity dielectrics.

  9. [Transcatheter aortic valve implantation for aortic stenosis. Initial experience].

    PubMed

    Careaga-Reyna, Guillermo; Lázaro-Castillo, José Luis; Lezama-Urtecho, Carlos Alberto; Macías-Miranda, Enriqueta; Dosta-Herrera, Juan José; Galván Díaz, José

    2016-12-09

    Aortic stenosis is a frequent disease in the elderly, and is associated with other systemic pathologies that may contraindicate the surgical procedure. Another option for these patients is percutaneous aortic valve implantation, which is less invasive. We present our initial experience with this procedure. Patients with aortic stenosis were included once selection criteria were accomplished. Under general anaesthesia and echocardiographic and fluosocopic control, a transcatheter aortic valve was implanted following s valvuloplasty. Once concluded the procedure, angiographic and pressure control was realized in order to confirm the valve function. Between November 2014 and May 2015, 6 patients were treated (4 males and 2 females), with a mean age of 78.83±5.66 years-old. The preoperative transvalvular gradient was 90.16±28.53mmHg and posterior to valve implant was 3.33±2.92mmHg (P<.05). Two patients had concomitant coronary artery disease which had been treated previously. One patient presented with acute right coronary artery occlusion which was immediately treated. However due to previous renal failure, postoperative sepsis and respiratory failure, the patient died one month later. It was concluded that our preliminary results showed that in selected patients percutaneous aortic valve implantation is a safe procedure with clinical improvement for treated patients. Copyright © 2016 Academia Mexicana de Cirugía A.C. Publicado por Masson Doyma México S.A. All rights reserved.

  10. Coronary Flow Impacts Aortic Leaflet Mechanics and Aortic Sinus Hemodynamics.

    PubMed

    Moore, Brandon L; Dasi, Lakshmi Prasad

    2015-09-01

    Mechanical stresses on aortic valve leaflets are well-known mediators for initiating processes leading to calcific aortic valve disease. Given that non-coronary leaflets calcify first, it may be hypothesized that coronary flow originating from the ostia significantly influences aortic leaflet mechanics and sinus hemodynamics. High resolution time-resolved particle image velocimetry (PIV) measurements were conducted to map the spatiotemporal characteristics of aortic sinus blood flow and leaflet motion with and without physiological coronary flow in a well-controlled in vitro setup. The in vitro setup consists of a porcine aortic valve mounted in a physiological aorta sinus chamber with dynamically controlled coronary resistance to emulate physiological coronary flow. Results were analyzed using qualitative streak plots illustrating the spatiotemporal complexity of blood flow patterns, and quantitative velocity vector and shear stress contour plots to show differences in the mechanical environments between the coronary and non-coronary sinuses. It is shown that the presence of coronary flow pulls the classical sinus vorticity deeper into the sinus and increases flow velocity near the leaflet base. This creates a beneficial increase in shear stress and washout near the leaflet that is not seen in the non-coronary sinus. Further, leaflet opens approximately 10% farther into the sinus with coronary flow case indicating superior valve opening area. The presence of coronary flow significantly improves leaflet mechanics and sinus hemodynamics in a manner that would reduce low wall shear stress conditions while improving washout at the base of the leaflet.

  11. Oxidative stress during abdominal aortic aneurysm repair--biomarkers and antioxidant's protective effect: a review.

    PubMed

    Aivatidi, C; Vourliotakis, G; Georgopoulos, S; Sigala, F; Bastounis, E; Papalambros, E

    2011-03-01

    Oxidative stress during abdominal aortic aneurysm (AAA) repair is likely to result as a response to an ischemia-reperfusion injury (IRI) to the lower limbs and gastrointestinal tract. This paper reviews the oxidative stress during AAA repair, with specific reference to biological markers and the potential antioxidant's protective effect. The current literature (1966 to July 2010) was reviewed specifically for all articles describing human studies relevant with the particular subject: oxidative stress in patients with AAA repair. Key-words used as single or combined searches included "abdominal aortic aneurysm", "open repair", "EVAR", "oxidative stress", "oxidation" and "antioxidant". A total of 14 relevant human studies were identified. In the majority of studies all samples (blood samples or/and muscle biopsies) were obtained from the patients using regional sampling techniques before or after anaesthesia, during aortic clamping or balloon occlusion (ischemic time) and after aortic clamp removal (reperfusion time) in different time intervals up to 24 or 48 hours. The oxidative status during AAA repair operation was evaluated by measuring quantitative changes of different substances including mainly vascular endothelial adhesion molecules, lipid peroxidation by-products or reactive oxygen species (ROS) and their metabolites. Two studies compared two groups of patients with AAA treated either by open or endovascular repair (EVAR), while four studies used different types of antioxidant supplementation in order to correlate it with a reduction in oxidative stress and damage in the antioxidant group of patients. Current evidence suggests that there is a high-grade oxidative stress during AAA repair operation. This was higher in cases of open repair beside EVAR and in cases with ruptured AAAs beside elective cases. The beneficial effect of an antioxidant supplementation in reducing the oxidative stress during AAA repair was also demonstrated. The use of a biological

  12. Aortic root replacement with a valve-sparing technique for quadricuspid aortic valve.

    PubMed

    Yamanaka, Katsuhiro; Okada, Kenji; Okita, Yutaka

    2015-04-01

    A 67-year old man with ascending aortic aneurysm was referred because of a quadricuspid aortic valve. He underwent aortic root replacement with a valve-sparing technique. Under deep hypothermic circulatory arrest, replacement of the ascending aorta was successfully performed. The postoperative course was uneventful without recurrence of aortic regurgitation.

  13. Vibration control of a flexible clamped-clamped plate based on an improved FULMS algorithm and laser displacement measurement

    NASA Astrophysics Data System (ADS)

    Xie, Lingbo; Qiu, Zhi-cheng; Zhang, Xian-min

    2016-06-01

    This paper presents a novel active resonant vibration control experiment of a flexible clamped-clamped plate using an improved filtered-U least mean square (FULMS) algorithm and laser displacement measurement. Different from the widely used PZT sensors or acceleration transducers, the vibration of the flexible clamped-clamped plate is measured by a non-contact laser displacement measurement sensor with higher measurement accuracy and without additional load to the plate. The conventional FULMS algorithm often uses fixed step size and needs reference signal related to the external disturbance signal. However, the fixed step size method cannot obtain a fast convergence speed and it will result in a low residual error. Thus, a variable step size method is investigated. In addition, it is difficult to extract reference signal related to the vibration source directly in the practical application. Therefore, it is practically useful that a reference signal is constructed by both the controller parameters and the vibration residual signal. The experimental results demonstrate that the improved FULMS algorithm has better vibration control effect than the proportional derivative (PD) feedback control algorithm and the fixed step-size control algorithm.

  14. Intervisceral artery origins in patients with abdominal aortic aneurysmal disease; evidence for systemic vascular remodelling.

    PubMed

    Bailey, Damian M; Evans, Tom G; Thomas, Kate Gower; White, Richard D; Twine, Chistopher P; Lewis, Michael H; Williams, Ian M

    2016-08-01

    What is the central question of this study? To what extent focal abdominal aortic aneurysmal (AAA) disease is associated with systemic remodelling of the vascular tree remains unknown. The present study examined whether anatomical differences exist between distances of the intervisceral artery origins and AAA location/size in patients with disease compared with healthy patients. What is the main finding and its importance? Intervisceral artery distances were shown to be consistently greater in AAA patients, highlighting the systemic nature of AAA disease that extends proximally to the abdominal aorta and its branches. The anatomical description of the natural variation in visceral artery origins has implications for the design of stent grafts and planning complex open aortic surgery. The initial histopathology of abdominal aortic aneurysmal (AAA) disease is atherosclerotic, later diverting towards a distinctive dilating rather than occlusive aortic phenotype. To what extent focal AAA disease is associated with systemic remodelling of the vascular tree remains unknown. The present study examined whether anatomical differences exist between the intervisceral artery origins and AAA location/size in patients with AAA disease (AAA+) relative to those without (AAA-). Preoperative contrast-enhanced computerized tomograms were reviewed in 90 consecutive AAA+ patients scheduled for open repair who underwent an infrarenal (n = 45), suprarenal (n = 26) or supracoeliac clamp (n = 19). These were compared with 39 age-matched AAA- control patients. Craniocaudal measurements were recorded from the distal origin of the coeliac artery to the superior mesenteric artery and from the origin of the superior mesenteric artery to both renal artery origins. Serial blood samples were obtained for estimation of the glomerular filtration rate before and after surgery. Intervisceral artery origins were shown to be consistently greater in AAA+ patients (P < 0.05 versus AAA-), although

  15. Thoracic aortopathy in Turner syndrome and the influence of bicuspid aortic valves and blood pressure: a CMR study

    PubMed Central

    2010-01-01

    Background To investigate aortic dimensions in women with Turner syndrome (TS) in relation to aortic valve morphology, blood pressure, karyotype, and clinical characteristics. Methods and results A cross sectional study of 102 women with TS (mean age 37.7; 18-62 years) examined by cardiovascular magnetic resonance (CMR- successful in 95), echocardiography, and 24-hour ambulatory blood pressure. Aortic diameters were measured by CMR at 8 positions along the thoracic aorta. Twenty-four healthy females were recruited as controls. In TS, aortic dilatation was present at one or more positions in 22 (23%). Aortic diameter in women with TS and bicuspid aortic valve was significantly larger than in TS with tricuspid valves in both the ascending (32.4 ± 6.7 vs. 26.0 ± 4.4 mm; p < 0.001) and descending (21.4 ± 3.5 vs. 18.8 ± 2.4 mm; p < 0.001) aorta. Aortic diameter correlated to age (R = 0.2 - 0.5; p < 0.01), blood pressure (R = 0.4; p < 0.05), a history of coarctation (R = 0.3; p = 0.01) and bicuspid aortic valve (R = 0.2-0.5; p < 0.05). Body surface area only correlated with descending aortic diameter (R = 0.23; p = 0.024). Conclusions Aortic dilatation was present in 23% of adult TS women, where aortic valve morphology, age and blood pressure were major determinants of the aortic diameter. PMID:20222980

  16. Spontaneous aortic dissection within an infrarenal AAA.

    PubMed

    Griffin, Kathryn J; Bailey, Marc A; McAree, Barry; Mekako, Anthony; Berridge, David C; Nicholson, Tony; Scott, D Julian A

    2012-12-01

    Aortic dissection occurring in the infrarenal abdominal aorta is uncommon. We present the case of a patient presenting with an enlarging abdominal aortic aneurysm and concurrent dissection (with associated radiological imaging) and briefly discuss the literature relating to this phenomenon.

  17. Abdominal aortic feminism.

    PubMed

    Mortimer, Alice Emily

    2014-11-14

    A 79-year-old woman presented to a private medical practice 2 years previously for an elective ultrasound screening scan. This imaging provided the evidence for a diagnosis of an abdominal aortic aneurysm (AAA) to be made. Despite having a number of recognised risk factors for an AAA, her general practitioner at the time did not follow the guidance set out by the private medical professional, that is, to refer the patient to a vascular specialist to be entered into a surveillance programme and surgically evaluated. The patient became symptomatic with her AAA, was admitted to hospital and found to have a tender, symptomatic, 6 cm leaking AAA. She consented for an emergency open AAA repair within a few hours of being admitted to hospital, despite the 50% perioperative mortality risk. The patient spent 4 days in intensive care where she recovered well. She was discharged after a 12 day hospital stay but unfortunately passed away shortly after her discharge from a previously undiagnosed gastric cancer. 2014 BMJ Publishing Group Ltd.

  18. Aortic Arch Interruption and Persistent Fifth Aortic Arch in Phace Syndrome: Prenatal Diagnosis and Postnatal Course.

    PubMed

    Chiappa, Enrico; Greco, Antonella; Fainardi, Valentina; Passantino, Silvia; Serranti, Daniele; Favilli, Silvia

    2015-09-01

    PHACE is a rare congenital neurocutaneous syndrome where posterior fossa malformations, hemangiomas, cerebrovascular anomalies, aortic arch anomalies, cardiac defects, and eye abnormalities are variably associated. We describe the prenatal detection and the postnatal course of a child with PHACE syndrome with a unique type of aortic arch anomaly consisting of proximal interruption of the aortic arch and persistence of the fifth aortic arch. The fifth aortic arch represented in this case a vital systemic-to-systemic connection between the ascending aorta and the transverse portion of the aortic arch allowing adequate forward flow through the aortic arch without surgical treatment.

  19. Current aortic endografts for the treatment of abdominal aortic aneurysms.

    PubMed

    Colvard, Benjamin; Georg, Yannick; Chakfe, Nabil; Swanstrom, Lee

    2016-05-01

    Endovascular Aneurysm Repair is a widely adopted method of treatment for patients with abdominal aortic aneurysms. The minimally invasive approach offered with EVAR has become popular not only among physicians and patients, but in the medical device industry as well. Over the past 25 years the global market for aortic endografts has increased rapidly, resulting in a wide range of devices from various companies. Currently, there are seven endografts approved by the FDA for the treatment of abdominal aortic aneurysms. These devices offer a wide range of designs intended to increase inclusion criteria while decreasing technical complications such as endoleak and migration. Despite advances in device design, secondary interventions and follow-up requirements remain a significant issue. New devices are currently being studied in the U.S. and abroad and may significantly reduce complications and secondary interventions.

  20. Management of bicuspid aortic valve with or without involvement of ascending aorta and aortic root.

    PubMed

    Neragi-Miandoab, S

    2014-06-01

    Patients with a bicuspid aortic valve (BAV) constitute a heterogeneous population with variable clinical presentation and complications. More than 50% of the patients who require aortic valve replacement have a BAV, a condition that may be associated with dilation of ascending aorta and aortic insufficiency caused by cusp disease or aortic root pathology. Of the potential BAV-related complications, dilation of the aortic root and ascending aorta are among the most serious. The dilation of ascending aorta and aortic root have been the subject of controversy. Whereas some surgeons believe that the dilation of the aorta is caused by the hemodynamic properties of the BAV, others believe that the dilation of the aortic root is secondary to genetic defects associated with the BAV. Management of a BAV should be tailored to each patient's clinical condition. The surgical approach varies from aortic valve replacement to combined aortic valve and root replacement to aortic-valve-sparing root replacement.

  1. Thoracic Aortic Aneurysm from Chronic Antiestrogen Therapy.

    PubMed

    Tripathi, Rishi; Sainathan, Sandeep; Ziganshin, Bulat A; Elefteriades, John A

    2017-03-01

    Aortic aneurysms are a common but often undetected pathology prevalent in the population. They are often detected as incidental findings on imaging studies performed for unrelated pathologies. Estrogens have been shown to exert a protective influence on aortic tissue. Pharmacological agents blocking the actions of estrogens may thus be implicated in causing aortic pathologies. We present the case of an elderly woman with breast carcinoma treated for 18 years with antiestrogen therapy who subsequently developed acute thoracic aortic deterioration (enlargement and wall disruption).

  2. Surgical Repair of Retrograde Type A Aortic Dissection after Thoracic Endovascular Aortic Repair

    PubMed Central

    Kim, Chang-Young; Kim, Yeon Soo; Ryoo, Ji Yoon

    2014-01-01

    It is expected that the stent graft will become an alternative method for treating aortic diseases or reducing the extent of surgery; therefore, thoracic endovascular aortic repair has widened its indications. However, it can have rare but serious complications such as paraplegia and retrograde type A aortic dissection. Here, we report a surgical repair of retrograde type A aortic dissection that was performed after thoracic endovascular aortic repair. PMID:24570865

  3. Evaluation the Aortic Aneurysm Remodeling After a Successful Stentgraft Implantation

    PubMed Central

    Nowicka, Monika; Kowalczyk, Agnieszka; Rusak, Grażyna; Ratajczak, Przemysław; Sobociński, Bartosz

    2016-01-01

    Summary Background Routine imaging follow-up after endovascular treatment of abdominal aortic aneurysms (EVAR) is mainly aimed at detection of endoleaks. The aim of the study was to assess changes in the size of the abdominal aortic aneurysm sack using CT angiography (CTA) after successful treatment using endovascular stent graft implantation. Material/Methods A retrospective analysis of CTA results included 102 patients aged 54–88, who had no postoperative complications. Patients underwent CTA before EVAR and after the treatment (mean time between studies, 7.6 months). The largest cross-sectional area of the aneurysm sac was measured using a curved multiplanar reconstruction. A change of the aneurysm cross-sectional over 10% was considered significant. Results The average cross-sectional area decreased after EVAR by 3% and this change was not statistically significant. Regression of the cross-sectional area was observed in 18.6% of patients, progression was in 23.5%, and no change was seen in 57.8%. Cross-sectional areas before and after EVAR were significantly correlated (r=0.75, p<0.0001). There was no correlation between the cross-sectional area change after EVAR and patients’ age or the time between the treatment and the follow-up CTA. Cross-sectional area before the treatment predicted changes in the aneurysm size after EVAR (p=0.0045). Conclusions Remodeling of abdominal aortic aneurysms after EVAR is not uniform. The change of aneurysm size depends on the initial aneurysm size but not on the time from EVAR. The size of the aneurysm after EVAR should not be considered as a measure of the treatment efficacy. PMID:27800038

  4. Impact of Aortic Valve Calcification, as Measured by MDCT, on Survival in Patients With Aortic Stenosis

    PubMed Central

    Clavel, Marie-Annick; Pibarot, Philippe; Messika-Zeitoun, David; Capoulade, Romain; Malouf, Joseph; Aggarval, Shivani; Araoz, Phillip A.; Michelena, Hector I.; Cueff, Caroline; Larose, Eric; Miller, Jordan D.; Vahanian, Alec; Enriquez-Sarano, Maurice

    2014-01-01

    BACKGROUND Aortic valve calcification (AVC) load measures lesion severity in aortic stenosis (AS) and is useful for diagnostic purposes. Whether AVC predicts survival after diagnosis, independent of clinical and Doppler echocardiographic AS characteristics, has not been studied. OBJECTIVES This study evaluated the impact of AVC load, absolute and relative to aortic annulus size (AVCdensity), on overall mortality in patients with AS under conservative treatment and without regard to treatment. METHODS In 3 academic centers, we enrolled 794 patients (mean age, 73 ± 12 years; 274 women) diagnosed with AS by Doppler echocardiography who underwent multidetector computed tomography (MDCT) within the same episode of care. Absolute AVC load and AVCdensity (ratio of absolute AVC to cross-sectional area of aortic annulus) were measured, and severe AVC was separately defined in men and women. RESULTS During follow-up, there were 440 aortic valve implantations (AVIs) and 194 deaths (115 under medical treatment). Univariate analysis showed strong association of absolute AVC and AVCdensity with survival (both, p < 0.0001) with a spline curve analysis pattern of threshold and plateau of risk. After adjustment for age, sex, coronary artery disease, diabetes, symptoms, AS severity on hemodynamic assessment, and LV ejection fraction, severe absolute AVC (adjusted hazard ratio [HR]: 1.75; 95% confidence interval [CI]: 1.04 to 2.92; p = 0.03) or severe AVCdensity (adjusted HR: 2.44; 95% CI: 1.37 to 4.37; p = 0.002) independently predicted mortality under medical treatment, with additive model predictive value (all, p ≤ 0.04) and a net reclassification index of 12.5% (p = 0.04). Severe absolute AVC (adjusted HR: 1.71; 95% CI: 1.12 to 2.62; p = 0.01) and severe AVCdensity (adjusted HR: 2.22; 95% CI: 1.40 to 3.52; p = 0.001) also independently predicted overall mortality, even with adjustment for time-dependent AVI. CONCLUSIONS This large-scale, multicenter outcomes study of

  5. Aortic or Mitral Valve Replacement With the Biocor and Biocor Supra

    ClinicalTrials.gov

    2016-03-09

    Aortic Valve Insufficiency; Aortic Valve Regurgitation; Aortic Valve Stenosis; Aortic Valve Incompetence; Mitral Valve Insufficiency; Mitral Valve Regurgitation; Mitral Valve Stenosis; Mitral Valve Incompetence

  6. Distinct roles for ATP binding and hydrolysis at individual subunits of an archaeal clamp loader

    PubMed Central

    Seybert, Anja; Wigley, Dale B

    2004-01-01

    Circular clamps are utilised by replicative polymerases to enhance processivity. The topological problem of loading a toroidal clamp onto DNA is overcome by ATP-dependent clamp loader complexes. Different organisms use related protein machines to load clamps, but the mechanisms by which they utilise ATP are surprisingly different. Using mutant clamp loaders that are deficient in either ATP binding or hydrolysis in different subunits, we show how the different subunits of an archaeal clamp loader use ATP binding and hydrolysis in distinct ways at different steps in the loading process. Binding of nucleotide by the large subunit and three of the four small subunits is sufficient for clamp loading. However, ATP hydrolysis by the small subunits is required for release of PCNA to allow formation of the complex between PCNA and the polymerase, while hydrolysis by the large subunit is required for catalytic clamp loading. PMID:15014449

  7. Timing of umbilical cord clamping: effect on iron endowment of the newborn and later iron status.

    PubMed

    Chaparro, Camila M

    2011-11-01

    The optimal timing of umbilical cord clamping has been debated in the scientific literature for at least the last century, when cord clamping practices shifted from delayed towards immediate clamping. Recent research provides evidence for the beneficial effect of delayed cord clamping on infant iron status. The present review describes the physiological basis for the impact of cord clamping time on total body iron at birth and the relationship between birth body iron, as affected by cord clamping time, and iron status later in infancy. This research is discussed in the context of current clamping practices, which tend towards early cord clamping in most settings, as well as the high levels of anemia present in young infants in many countries worldwide. © 2011 International Life Sciences Institute.

  8. Portal triad clamping or hepatic vascular exclusion for major liver resection. A controlled study.

    PubMed Central

    Belghiti, J; Noun, R; Zante, E; Ballet, T; Sauvanet, A

    1996-01-01

    OBJECTIVE: The authors compared operative course of patients undergoing major liver resections under portal triad clamping (PTC) or under hepatic vascular exclusion (HVE). SUMMARY BACKGROUND DATA: Reduced blood loss during liver resection is achieved by PTC or HVE. Specific complications and postoperative hepatocellular injury mediated with two procedures have not been compared. METHODS: Fifty-two noncirrhotic patients undergoing major liver resections were included in a prospective randomized study comparing both the intraoperative and postoperative courses under PTC (n = 24) or under HVE (n = 28). RESULTS: The two groups were similar at entry, but eight patients were crossed over to the other group during resection. In the HVE group, hemodynamic intolerance occurred in four (14%) patients. In the PTC group, pedicular clamping was not efficient in four patients, including three with involvement of the cavohepatic intersection and one with persistent bleeding due to tricuspid insufficiency. Intraoperative blood losses and postoperative enzyme level reflecting hepatocellular injury were similar in the two groups. Mean operative duration and mean clampage duration were significantly increased after HVE. Postoperative abdominal collections and pulmonary complications were 2.5-fold higher after HVE but without statistical significance, whereas the mean length of postoperative hospital stay was longer after HVE. CONCLUSIONS: This study shows that both methods of vascular occlusion are equally effective in reducing blood loss in major liver resections. The HVE is associated with unpredictable hemodynamic intolerance, increased postoperative complications with a longer hospital stay, and should be restricted to lesions involving the cavo-hepatic intersection. PMID:8757378

  9. Balloon aortic valvuloplasty as a bridge to aortic valve replacement in a patient with severe calcific aortic stenosis

    PubMed Central

    Swinkels, B.M.; Jaarsma, W.; Wely, L. Relik-van; van Swieten, H.A.; Ernst, J.M.P.G.; Plokker, H.W.M.

    2003-01-01

    This case report describes a patient with severe calcific aortic stenosis who was initially considered inoperable because of a very poor left ventricular function and severe pulmonary hypertension. After balloon aortic valvuloplasty, the clinical and haemodynamic status of the patient improved to such an extent that subsequent aortic valve replacement was considered possible and eventually proved to be successful. Balloon aortic valvuloplasty has value as a potential bridge to aortic valve replacement when the risks for surgery are considered to be too high. ImagesFigure 1 PMID:25696195

  10. Pseudoaneurysm of the aortic arch

    PubMed Central

    Lu, Yuan-Qiang; Yao, Feng; Shang, An-Dong; Pan, Jian

    2016-01-01

    Abstract Background: Pseudoaneurysm of the aortic arch is uncommonly associated with cancer, and is extremely rare in pulmonary cancer. Here, we report an unusual and successfully treated case of aortic arch pseudoaneurysm in a male patient with lung squamous cell carcinoma. Methods: A 64-year-old male patient was admitted to the Emergency Department, presenting with massive hemoptysis (>500 mL blood during the 12 hours prior to treatment). The diagnosis of aortic arch pseudoaneurysm was confirmed after inspection of computed tomographic angiography and three-dimensional reconstruction. We processed the immediate endovascular stent-grafting for this patient. Results: This patient recovered with no filling or enlargement of the pseudoaneurysm, no episodes of hemoptysis, and no neurological complications during the 4-week follow-up period. Conclusion: Herein, we compare our case with other cancer-related pseudoaneurysms in the medical literature and summarize the clinical features and treatment of this unusual case. PMID:27495079

  11. A High-Efficiency Diode-Clamped Linear Amplifier

    NASA Astrophysics Data System (ADS)

    Fujita, Hideaki

    This paper proposes a new power converter without any switching operation, which works as a linear amplifier. The main circuit of the proposed converter consists of series-connected MOSFETs, series-multi dc power supplies and clamping diodes. The circuit configuration is similar to a diode-clamped multi-level inverter, except for using complementary power devices, which are n- and p-channel MOSFETs. One of the series-connected MOSFETs operates in an active state just like a linear amplifier, while the other MOSFETs operate in on or off states like an inverter circuit. As a result, the proposed converter achieves an acceptable efficiency as high as 90% without any ripples nor harmonics caused by switching operation. Experimental results demonstrate that the proposed converter has capability of driving a 2.2-kW three-phase induction motor.

  12. Patch-clamp experiments under micro-gravity.

    PubMed

    Meissner, Klaus; Hanke, Wolfgang

    2002-07-01

    For human based space research it is of high importance to understand the influence of gravity on the properties of single ion channels in biological membranes, as these are involved in about all biological processes. The patch clamp technique is the best established method to investigate electrophysiological properties of single ion channels in detail. Consequently, a patch clamp set-up was designed for the drop tower in Bremen, Germany. Using this set-up among others, successfully leech neurons have been patched under micro-gravity, delivering data about ion channel behaviour, which were compared to results from bilayer experiments in the drop tower and to results from lab controls under 1 g and under higher gravity.

  13. Active energy recovery clamping circuit to improve the performance of power converters

    DOEpatents

    Whitaker, Bret; Barkley, Adam

    2017-05-09

    A regenerative clamping circuit for a power converter using clamping diodes to transfer charge to a clamping capacitor and a regenerative converter to transfer charge out of the clamping capacitor back to the power supply input connection. The regenerative converter uses a switch connected to the midpoint of a series connected inductor and capacitor. The ends of the inductor and capacitor series are connected across the terminals of the power supply to be in parallel with the power supply.

  14. Severe aortic stenosis: forgotten associations.

    PubMed

    Godinho, Ana Rita; Amorim, Sandra; Campelo, Manuel; Martins, Elisabete; Lopez Rodriguez, Elisa; Coelho, Rosa; Macedo, Guilherme; Maciel, Maria Júlia

    2014-09-01

    The authors present the case of a 68-year-old man with predominantly right heart failure in the context of severe aortic stenosis associated with pulmonary hypertension. Anemia was diagnosed which, after endoscopic study, was considered to be secondary to angiodysplasia and a diagnosis of Heyde syndrome was made. After valve replacement surgery the patient's heart failure improved and hemoglobin levels stabilized. We present this case to show the need to recognize less common associations of severe aortic stenosis, in order to provide immediate and appropriate treatment.

  15. Aortic and other arterial injuries.

    PubMed

    Hardy, J D; Raju, S; Neely, W A; Berry, D W

    1975-05-01

    Three hundred sixty arterial injuries in 353 patients are reviewed. They covered a wide spectrum of injuries and included 36 aortic injuries and 19 cases of carotid truama. The mortality rate of 12% was in large part due to aortic injuries. Shock was the predominant cause of death. Infection was the most frequent non-fatal complication. Pulmonary complications were surprisingly uncommon. With methods and techniques discussed in the paper, 90% satisfactory end results were achieved. The amputation rate was 6% where extremity injuries were involved.

  16. Aortic and other arterial injuries.

    PubMed Central

    Hardy, J D; Raju, S; Neely, W A; Berry, D W

    1975-01-01

    Three hundred sixty arterial injuries in 353 patients are reviewed. They covered a wide spectrum of injuries and included 36 aortic injuries and 19 cases of carotid truama. The mortality rate of 12% was in large part due to aortic injuries. Shock was the predominant cause of death. Infection was the most frequent non-fatal complication. Pulmonary complications were surprisingly uncommon. With methods and techniques discussed in the paper, 90% satisfactory end results were achieved. The amputation rate was 6% where extremity injuries were involved. Images Fig. 11. Fig. 13. PMID:1130881

  17. Cleaning patch-clamp pipettes for immediate reuse

    PubMed Central

    Kolb, I.; Stoy, W. A.; Rousseau, E. B.; Moody, O. A.; Jenkins, A.; Forest, C. R.

    2016-01-01

    Patch-clamp recording has enabled single-cell electrical, morphological and genetic studies at unparalleled resolution. Yet it remains a laborious and low-throughput technique, making it largely impractical for large-scale measurements such as cell type and connectivity characterization of neurons in the brain. Specifically, the technique is critically limited by the ubiquitous practice of manually replacing patch-clamp pipettes after each recording. To circumvent this limitation, we developed a simple, fast, and automated method for cleaning glass pipette electrodes that enables their reuse within one minute. By immersing pipette tips into Alconox, a commercially-available detergent, followed by rinsing, we were able to reuse pipettes 10 times with no degradation in signal fidelity, in experimental preparations ranging from human embryonic kidney cells to neurons in culture, slices, and in vivo. Undetectable trace amounts of Alconox remaining in the pipette after cleaning did not affect ion channel pharmacology. We demonstrate the utility of pipette cleaning by developing the first robot to perform sequential patch-clamp recordings in cell culture and in vivo without a human operator. PMID:27725751

  18. A mathematical model of the euglycemic hyperinsulinemic clamp

    PubMed Central

    Picchini, Umberto; De Gaetano, Andrea; Panunzi, Simona; Ditlevsen, Susanne; Mingrone, Geltrude

    2005-01-01

    Background The Euglycemic Hyperinsulinemic Clamp (EHC) is the most widely used experimental procedure for the determination of insulin sensitivity, and in its usual form the patient is followed under insulinization for two hours. In the present study, sixteen subjects with BMI between 18.5 and 63.6 kg/m2 were studied by long-duration (five hours) EHC. Results From the results of this series and from similar reports in the literature it is clear that, in obese subjects, glucose uptake rates continue to increase if the clamp procedure is prolonged beyond the customary 2 hours. A mathematical model of the EHC, incorporating delays, was fitted to the recorded data, and the insulin resistance behaviour of obese subjects was assessed analytically. Obese subjects had significantly less effective suppression of hepatic glucose output and higher pancreatic insulin secretion than lean subjects. Tissue insulin resistance appeared to be higher in the obese group, but this difference did not reach statistical significance. Conclusion The use of a mathematical model allows a greater amount of information to be recovered from clamp data, making it easier to understand the components of insulin resistance in obese vs. normal subjects. PMID:16269082

  19. Cleaning patch-clamp pipettes for immediate reuse.

    PubMed

    Kolb, I; Stoy, W A; Rousseau, E B; Moody, O A; Jenkins, A; Forest, C R

    2016-10-11

    Patch-clamp recording has enabled single-cell electrical, morphological and genetic studies at unparalleled resolution. Yet it remains a laborious and low-throughput technique, making it largely impractical for large-scale measurements such as cell type and connectivity characterization of neurons in the brain. Specifically, the technique is critically limited by the ubiquitous practice of manually replacing patch-clamp pipettes after each recording. To circumvent this limitation, we developed a simple, fast, and automated method for cleaning glass pipette electrodes that enables their reuse within one minute. By immersing pipette tips into Alconox, a commercially-available detergent, followed by rinsing, we were able to reuse pipettes 10 times with no degradation in signal fidelity, in experimental preparations ranging from human embryonic kidney cells to neurons in culture, slices, and in vivo. Undetectable trace amounts of Alconox remaining in the pipette after cleaning did not affect ion channel pharmacology. We demonstrate the utility of pipette cleaning by developing the first robot to perform sequential patch-clamp recordings in cell culture and in vivo without a human operator.

  20. Force-clamp laser trapping of rapidly interacting molecules

    NASA Astrophysics Data System (ADS)

    Capitanio, Marco; Monico, Carina; Vanzi, Francesco; Pavone, Francesco S.

    2013-06-01

    Forces play a fundamental role in a wide array of biological processes, regulating enzymatic activity, kinetics of molecular bonds, and molecular motors mechanics. Single molecule force spectroscopy techniques have enabled the investigation of such processes, but they are inadequate to probe short-lived (millisecond and sub-millisecond) molecular complexes. We developed an ultrafast force-clamp spectroscopy technique that uses a dual trap configuration to apply constant loads to a single intermittently interacting biological polymer and a binding protein. Our system displays a delay of only ˜10 μs between formation of the molecular bond and application of the force and is capable of detecting interactions as short as 100 μs. The force-clamp configuration in which our assay operates allows direct measurements of load-dependence of lifetimes of single molecular bonds. Moreover, conformational changes of single proteins and molecular motors can be recorded with sub-nanometer accuracy and few tens of microseconds of temporal resolution. We demonstrate our technique on molecular motors, using myosin II from fast skeletal muscle and on protein-DNA interaction, specifically on Lactose repressor (LacI). The apparatus is stabilized to less than 1 nm with both passive and active stabilization, allowing resolving specific binding regions along the actin filament and DNA molecule. Our technique extends single-molecule force-clamp spectroscopy to molecular complexes that have been inaccessible up to now, opening new perspectives for the investigation of the effects of forces on biological processes.

  1. DNA Sliding Clamps: Just the Right Twist to Load onto DNA

    SciTech Connect

    Barsky, D; Venclovas, C

    2005-10-24

    Two recent papers illuminate a long sought step in DNA sliding clamp loading. One paper reveals the structure of the PCNA clamp wrapped around DNA--still open from being loaded--while a second paper discovers that the clamp may assist this process by forming a right-handed helix upon opening.

  2. Pressure controlled clamp using shape memory alloy for minimal vessel invasion in blood flow occlusion.

    PubMed

    Zhang, Ye; Kanetaka, Hiroyasu; Sano, Yuya; Kano, Mitsuhiro; Kudo, Tadaaki; Sato, Takumi; Shimizu, Yoshinaka

    2013-01-01

    Vessel damage after clamping may affect the success of surgical operations. A new pressure controlled clamp (SMA clamp) was designed using super elastic property of shape memory alloy (SMA) to realize atraumatic vessel occlusion. The ability and biological effect of the SMA clamp to control pressure was investigated in vivo. The loading-displacement curves of the SMA clamps (experimental group) and conventional clamp (control group) by occlusion of pig carotid arteries were evaluated using a clamping-pressure analyzing system. To investigate macroscopically and histologically the vessel damage of the SMA and conventional clamps, pig carotid arteries were stained with Evan's blue and its histological sections were stained with Elastica Massion after clamping for fifteen minutes. Constant value was shown in the loading-displacement curve of SMA clamp. In the control group, damaged area stained with Evan's blue in the vessel wall showed enlargement with the pressure increasing. Less areas in experimental groups are observed than that in the control group. Histological section in the experimental group showed no obvious except a slight compressive damage in the tunica intima. In the control group, vessel wall showed irreversible damages. This experiment indicated that the SMA clamp, which has a unique mechanical property, can be used without vessels damage. This pressure controlled clamp can be a selection in clinical apparatus to improve surgical safety.

  3. Metric characterization of the aortic arch of early mouse fetuses and of a fetus featuring a double lumen aortic arch malformation.

    PubMed

    Geyer, Stefan H; Weninger, Wolfgang J

    2013-03-01

    This study aimed at providing an objective metric characterization of the aortic arch of a mouse fetus featuring a double lumen aortic arch malformation. As a side effect it provides reference data defining the length and the diameters of the aortic arch segments of normally developed mouse fetuses at developmental stage 22 according to Theiler (TS22). We analyzed a total of 22 TS22 mouse fetuses of the Him:OF1 strain. We produced high-resolution three-dimensional (3D) computer models and measured the diameters and cross sectional areas of the aortic arch segments and of the ascending and descending aorta. In addition, we defined 3D skeletons of the arteries and measured the length of the aortic arch segments. We provide statistics on the measurements obtained from the normally developed TS22 fetuses and detailed characterizations of the double lumen aortic arch. Our data suggest that: firstly, in Him:OF1 fetuses of TS22, the formation of the aortic arch is not yet finished. The left subclavian artery still receives a significant amount of blood from the right ventricle. Secondly, persistence of the 5th pharyngeal arch artery does not affect remodeling of the arteries distal to the junction of 5th pharyngeal arch artery and dorsal aorta. Thirdly, hemodynamic forces define the dimensions of the aortic arch between the left common carotid and the left subclavian artery. Fourthly, the blood volume streaming through the 4th pharyngeal arch artery influences its enlargement between TS20 and TS22. Copyright © 2012 Elsevier GmbH. All rights reserved.

  4. Preliminary results from a prospective study of laparoscopic aortobifemoral bypass using a clampless and sutureless aortic anastomotic technique.

    PubMed

    Segers, B; Horn, D; Lemaitre, J; Roman, A; Stevens, E; Van Den Broeck, V; Hizette, P; Bosschaerts, T

    2014-10-01

    This prospective study describes the feasibility and safety of a new clampless and sutureless aortic anastomotic technique used during retroperitoneal laparoscopic aortobifemoral bypass in extensive aortoiliac occlusive lesions. This is a case series of a previously published technique, demonstrating wider applicability of the technique. Twelve patients underwent a clampless and sutureless laparoscopic bypass for TASC D aortoiliac occlusive lesions using the EndoVascular REtroperitoneoScopic Technique (EVREST). Dissection of the retroperitoneal space and the infrarenal aorta was performed laparoscopically. A bifurcated graft was inserted into the retroperitoneal space. The main body of the graft was connected on the left side of the aorta by an intra- and extra-aortic covered stent-graft. An aortic clamp was used temporarily on four patients because of excessive bleeding when the connector was deployed. The femoral anastomoses were performed by classic open surgery. Initial technical success, complications, and bypass patency were assessed. Median follow-up was 9.3 months. Median operative time was 265 minutes. Median duration of aorto-prosthetic connection was 60 seconds. Thirty-day postoperative mortality was 0%. No major postoperative complications were observed. All grafts were patent at the end of follow-up and there was no early or late disruption of the proximal assembly. EVREST greatly facilitates laparoscopic aortic surgery in occlusive disease with no need for suture or clamping of the aorta. This technique performed in a single center on 12 patients, seems to be feasible and safe. It offers the advantages of laparoscopy and those of endovascular surgery, especially in the challenging conditions encountered during aortic laparoscopic surgery. Early experience supports procedural and initial postprocedural safety and demonstrates proof-of-concept for EVREST. Copyright © 2014 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights

  5. Predictive risk models for proximal aortic surgery

    PubMed Central

    Díaz, Rocío; Pascual, Isaac; Álvarez, Rubén; Alperi, Alberto; Rozado, Jose; Morales, Carlos; Silva, Jacobo; Morís, César

    2017-01-01

    Predictive risk models help improve decision making, information to our patients and quality control comparing results between surgeons and between institutions. The use of these models promotes competitiveness and led to increasingly better results. All these virtues are of utmost importance when the surgical operation entails high-risk. Although proximal aortic surgery is less frequent than other cardiac surgery operations, this procedure itself is more challenging and technically demanding than other common cardiac surgery techniques. The aim of this study is to review the current status of predictive risk models for patients who undergo proximal aortic surgery, which means aortic root replacement, supracoronary ascending aortic replacement or aortic arch surgery. PMID:28616348

  6. Predictive risk models for proximal aortic surgery.

    PubMed

    Hernandez-Vaquero, Daniel; Díaz, Rocío; Pascual, Isaac; Álvarez, Rubén; Alperi, Alberto; Rozado, Jose; Morales, Carlos; Silva, Jacobo; Morís, César

    2017-05-01

    Predictive risk models help improve decision making, information to our patients and quality control comparing results between surgeons and between institutions. The use of these models promotes competitiveness and led to increasingly better results. All these virtues are of utmost importance when the surgical operation entails high-risk. Although proximal aortic surgery is less frequent than other cardiac surgery operations, this procedure itself is more challenging and technically demanding than other common cardiac surgery techniques. The aim of this study is to review the current status of predictive risk models for patients who undergo proximal aortic surgery, which means aortic root replacement, supracoronary ascending aortic replacement or aortic arch surgery.

  7. Acute aortic dissection at two extreme ages.

    PubMed

    Ramzisham, A R M; Arief, H; Ngoo, K S; Zamrin, D M; Joanna, O S M

    2011-01-01

    Acute aortic dissection is a life-threatening condition, warranting prompt diagnosis and treatment. Management of which incorporates multidisciplinary expertise from the medical, surgical and intensive care. If left untreated, the mortality rate of acute aortic disease exceeds 50% within 48 hours and 80% within two weeks, with a 5-year survival rate of 19%. The most common cause of death in untreated acute aortic dissection, regardless of aetiology, is aortic rupture. We would like to share our successful experience of cases at the two extreme ages of acute aortic dissection. Literature review with their pathogenesis are discussed.

  8. MMP-2 Isoforms in Aortic Tissue and Serum of Patients with Ascending Aortic Aneurysms and Aortic Root Aneurysms

    PubMed Central

    Tscheuschler, Anke; Meffert, Philipp; Beyersdorf, Friedhelm; Heilmann, Claudia; Kocher, Nadja; Uffelmann, Xenia; Discher, Philipp; Siepe, Matthias; Kari, Fabian A.

    2016-01-01

    Objective The need for biological markers of aortic wall stress and risk of rupture or dissection of ascending aortic aneurysms is obvious. To date, wall stress cannot be related to a certain biological marker. We analyzed aortic tissue and serum for the presence of different MMP-2 isoforms to find a connection between serum and tissue MMP-2 and to evaluate the potential of different MMP-2 isoforms as markers of high wall stress. Methods Serum and aortic tissue from n = 24 patients and serum from n = 19 healthy controls was analyzed by ELISA and gelatin zymography. 24 patients had ascending aortic aneurysms, 10 of them also had aortic root aneurysms. Three patients had normally functioning valves, 12 had regurgitation alone, eight had regurgitation and stenosis and one had only stenosis. Patients had bicuspid and tricuspid aortic valves (9/15). Serum samples were taken preoperatively, and the aortic wall specimen collected during surgical aortic repair. Results Pro-MMP-2 was identified in all serum and tissue samples. Pro-MMP-2 was detected in all tissue and serum samples from patients with ascending aortic/aortic root aneurysms, irrespective of valve morphology or other clinical parameters and in serum from healthy controls. We also identified active MMP-2 in all tissue samples from patients with ascending aortic/aortic root aneurysms. None of the analyzed serum samples revealed signals relatable to active MMP-2. No correlation between aortic tissue total MMP-2 or tissue pro-MMP-2 or tissue active MMP-2 and serum MMP-2 was found and tissue MMP-2/pro-MMP-2/active MMP-2 did not correlate with aortic diameter. This evidence shows that pro-MMP-2 is the predominant MMP-2 species in serum of patients and healthy individuals and in aneurysmatic aortic tissue, irrespective of aortic valve configuration. Active MMP-2 species are either not released into systemic circulation or not detectable in serum. There is no reliable connection between aortic tissue—and serum MMP-2

  9. Transcatheter aortic-valve replacement for inoperable severe aortic stenosis.

    PubMed

    Makkar, Raj R; Fontana, Gregory P; Jilaihawi, Hasan; Kapadia, Samir; Pichard, Augusto D; Douglas, Pamela S; Thourani, Vinod H; Babaliaros, Vasilis C; Webb, John G; Herrmann, Howard C; Bavaria, Joseph E; Kodali, Susheel; Brown, David L; Bowers, Bruce; Dewey, Todd M; Svensson, Lars G; Tuzcu, Murat; Moses, Jeffrey W; Williams, Matthew R; Siegel, Robert J; Akin, Jodi J; Anderson, William N; Pocock, Stuart; Smith, Craig R; Leon, Martin B

    2012-05-03

    Transcatheter aortic-valve replacement (TAVR) is the recommended therapy for patients with severe aortic stenosis who are not suitable candidates for surgery. The outcomes beyond 1 year in such patients are not known. We randomly assigned patients to transfemoral TAVR or to standard therapy (which often included balloon aortic valvuloplasty). Data on 2-year outcomes were analyzed. A total of 358 patients underwent randomization at 21 centers. The rates of death at 2 years were 43.3% in the TAVR group and 68.0% in the standard-therapy group (P<0.001), and the corresponding rates of cardiac death were 31.0% and 62.4% (P<0.001). The survival advantage associated with TAVR that was seen at 1 year remained significant among patients who survived beyond the first year (hazard ratio, 0.58; 95% confidence interval [CI], 0.36 to 0.92; P=0.02 with the use of the log-rank test). The rate of stroke was higher after TAVR than with standard therapy (13.8% vs. 5.5%, P=0.01), owing, in the first 30 days, to the occurrence of more ischemic events in the TAVR group (6.7% vs. 1.7%, P=0.02) and, beyond 30 days, to the occurrence of more hemorrhagic strokes in the TAVR group (2.2% vs. 0.6%, P=0.16). At 2 years, the rate of rehospitalization was 35.0% in the TAVR group and 72.5% in the standard-therapy group (P<0.001). TAVR, as compared with standard therapy, was also associated with improved functional status (P<0.001). The data suggest that the mortality benefit after TAVR may be limited to patients who do not have extensive coexisting conditions. Echocardiographic analysis showed a sustained increase in aortic-valve area and a decrease in aortic-valve gradient, with no worsening of paravalvular aortic regurgitation. Among appropriately selected patients with severe aortic stenosis who were not suitable candidates for surgery, TAVR reduced the rates of death and hospitalization, with a decrease in symptoms and an improvement in valve hemodynamics that were sustained at 2 years of

  10. Planar silicon patch-clamp electrodes integrated with polydimethylsiloxane microfluidics

    NASA Astrophysics Data System (ADS)

    Nagarah, John Michael

    The patch-clamp technique allows one to probe single ion channels and macroscopic ion channel activity in their native environment and resolve their activity as their physical and chemical surroundings are varied. The traditional method of patch-clamping cells involves bringing a clean, flame-polished glass pipette tip with a 1-2 mum diameter pore into contact with a cell membrane to form a high electrical resistance seal. This technique is the gold standard for cellular electrophysiology investigations because it allows the observation of single ion channel protein dynamics as well as activity from an ensemble ion channels from a single cell. Furthermore, any drug approved by federal drug agencies must be screened against particular ion channels with the patch-clamp technique. However, this technique by its nature is serial, time consuming, difficult when exchanging pipette solutions, and difficult to integrate with other technologies. These reasons have prompted several investigators to explore alternative approaches to traditional pipette patch-clamping to increase the throughput of measurements. Herein, I describe the development of a silicon-wafer based device platform that enables the measurement of ion channel activities. The electrical nature of the cell/wafer seal is characterized for several pore design variations. The majority of gigaohm seals obtained falls in the range of 10-20GO. The cell-attached and whole cell configurations are demonstrated. Whole cell ion channel activity originating from various cell fines is consistent with the more traditional micropipette patch-clamp recordings. The silicon fabrication methods developed, although novel, utilize established semiconductor technologies, making them amenable to batch fabrication techniques. I integrate these silicon devices with PDMS microfluidics with monolithic valves, allowing ultra-fast solution exchange as low as tens of milliseconds for the extracellular solution. Furthermore, I developed a

  11. Aortic Wall Injury Related to Endovascular Therapy for Aortic Coarctation.

    PubMed

    Tretter, Justin T; Jones, Thomas K; McElhinney, Doff B

    2015-09-01

    Aortic wall complications can occur in unrepaired aortic coarctation (CoA) and after surgical repair or endovascular treatment. This review summarizes the available literature and current understanding of aortic wall injury (AWI) surrounding the management of CoA, focusing specifically on acute and follow-up AWI after endovascular treatment. There have been 23 reported cases of aortic rupture after endovascular treatment for CoA, including angioplasty alone, bare metal stenting, and primary covered stent therapy. Even if these published cases represent only a minority of ruptures that have actually occurred, the incidence is substantially <1%. The incidence of acute aneurysm formation was 0% to 13% after angioplasty, 0% to 5% after bare metal stent placement, and <1% after covered stent placement. The reported incidence and natural history of both acute and new AWI during follow-up after endovascular therapy for CoA varies considerably, likely secondary to ascertainment and reporting biases and inconsistent definitions. Although important AWI after endovascular treatment of CoA seems to be declining in frequency with increasing experience and improving technology, it remains one of the most important potential adverse outcomes. Long-term surveillance for new AWI and monitoring of existing AWI is mandatory, with institution of appropriate treatment when necessary. A central research focus in this population should be determination of the appropriate treatment for both native and recurrent CoA across various ages with regard to limiting recurrent CoA and preventing associated aortic wall complications, in addition to determining the appropriate treatment of various AWI. Consistent definitions and reporting are necessary to truly understand the incidence of, risk factors for, and measures protective against AWI after angioplasty or stent implantation for CoA.

  12. Genetic and Epigenetic Regulation of Aortic Aneurysms

    PubMed Central

    Kim, Ha Won

    2017-01-01

    Aneurysms are characterized by structural deterioration of the vascular wall leading to progressive dilatation and, potentially, rupture of the aorta. While aortic aneurysms often remain clinically silent, the morbidity and mortality associated with aneurysm expansion and rupture are considerable. Over 13,000 deaths annually in the United States are attributable to aortic aneurysm rupture with less than 1 in 3 persons with aortic aneurysm rupture surviving to surgical intervention. Environmental and epidemiologic risk factors including smoking, male gender, hypertension, older age, dyslipidemia, atherosclerosis, and family history are highly associated with abdominal aortic aneurysms, while heritable genetic mutations are commonly associated with aneurysms of the thoracic aorta. Similar to other forms of cardiovascular disease, family history, genetic variation, and heritable mutations modify the risk of aortic aneurysm formation and provide mechanistic insight into the pathogenesis of human aortic aneurysms. This review will examine the relationship between heritable genetic and epigenetic influences on thoracic and abdominal aortic aneurysm formation and rupture. PMID:28116311

  13. Aortic Root Enlargement or Sutureless Valve Implantation?

    PubMed Central

    Baikoussis, Nikolaos G.; Dedeilias, Panagiotis; Argiriou, Michalis

    2016-01-01

    Aortic valve replacement (AVR) in patients with a small aortic annulus is a challenging issue. The importance of prosthesis–patient mismatch (PPM) post aortic valve replacement (AVR) is controversial but has to be avoided. Many studies support the fact that PPM has a negative impact on short and long term survival. In order to avoid PPM, aortic root enlargement may be performed. Alternatively and keeping in mind that often some comorbidities are present in old patients with small aortic root, the Perceval S suturelles valve implantation could be a perfect solution. The Perceval sutureless bioprosthesis provides reasonable hemodynamic performance avoiding the PPM and providing the maximum of aortic orifice area. We would like to see in the near future the role of the aortic root enlargement techniques in the era of surgical implantation of the sutureless valve (SAVR) and the transcatheter valve implantation (TAVI). PMID:28028424

  14. Notch-dependent EMT is attenuated in patients with aortic aneurysm and bicuspid aortic valve.

    PubMed

    Kostina, Aleksandra S; Uspensky, Vladimir Е; Irtyuga, Olga B; Ignatieva, Elena V; Freylikhman, Olga; Gavriliuk, Natalia D; Moiseeva, Olga M; Zhuk, Sergey; Tomilin, Alexey; Kostareva, Аnna А; Malashicheva, Anna B

    2016-04-01

    Bicuspid aortic valve is the most common congenital heart malformation and the reasons for the aortopathies associated with bicuspid aortic valve remain unclear. NOTCH1 mutations are associated with bicuspid aortic valve and have been found in individuals with various left ventricular outflow tract abnormalities. Notch is a key signaling during cardiac valve formation that promotes the endothelial-to-mesenchymal transition. We address the role of Notch signaling in human aortic endothelial cells from patients with bicuspid aortic valve and aortic aneurysm. Aortic endothelial cells were isolated from tissue fragments of bicuspid aortic valve-associated thoracic aortic aneurysm patients and from healthy donors. Endothelial-to-mesenchymal transition was induced by activation of Notch signaling. Effectiveness of the transition was estimated by loss of endothelial and gain of mesenchymal markers by immunocytochemistry and qPCR. We show that aortic endothelial cells from the patients with aortic aneurysm and bicuspid aortic valve have down regulated Notch signaling and fail to activate Notch-dependent endothelial-to-mesenchymal transition in response to its stimulation by different Notch ligands. Our findings support the idea that bicuspid aortic valve and associated aortic aneurysm is associated with dysregulation of the entire Notch signaling pathway independently on the specific gene mutation.

  15. Effect of Delayed Cord Clamping on Systemic Blood Flow: A Randomized Controlled Trial.

    PubMed

    Popat, Himanshu; Robledo, Kristy P; Sebastian, Lucille; Evans, Nicholas; Gill, Andrew; Kluckow, Martin; Sinhal, Sanjay; de Waal, Koert; Tarnow-Mordi, William; Osborn, David

    2016-11-01

    To determine whether delayed cord clamping improves systemic blood flow compared with immediate cord clamping in very preterm infants in the first 24 hours. Women delivering at <30 weeks' gestation at 5 tertiary centers were randomized to receive immediate cord clamping (<10 seconds) or delayed cord clamping (≥60 seconds). Echocardiography and cardiorespiratory data were collected at 3, 9, and 24 hours after birth. The primary outcome was mean lowest superior vena cava (SVC) flow. Of 266 infants enrolled, 133 were randomized to immediate cord clamping and 133 to delayed cord clamping. The 2 groups were similar at baseline, including mean gestation (immediate cord clamping 28 weeks vs delayed cord clamping 28 weeks) and birth weight (immediate cord clamping 1003 g vs delayed cord clamping 1044 g). There was no significant difference between groups in the primary outcome of mean lowest SVC flow (immediate cord clamping 71.4 mL/kg/min [SD 28.1] vs delayed cord clamping 70.2 mL/kg/min [SD 26.9]; P = .7). For secondary outcomes, hemoglobin increased by 0.9 g/dL at 6 hours in the group with delayed cord clamping (95% CI 3.9, 14.4; P = .0005, adjusted for baseline). The group with delayed cord clamping had lower right ventricular output (-21.9 mL/kg/min, 95% CI -39.0, -4.7; P = .01). Rates of treated hypotension, ductus arteriosus size and shunt direction, and treatment of the ductus arteriosus were similar. Delayed cord clamping had no effect on systemic blood flow measured as mean lowest SVC flow in the first 24 hours in infants <30 weeks' gestation. Australia New Zealand Clinical Trials Registry: ACTRN12610000633088. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Extracellular potassium accumulation in voltage-clamped frog ventricular muscle.

    PubMed Central

    Cleemann, L; Morad, M

    1979-01-01

    1. Application of voltage clamp pulses (1--10 sec) to frog ventricular strips causes temporary changes in the extracellular K concentration. 2. The changes in the extracellular K concentration can be estimated from (a) slowly decaying post-clamp after-potentials, (b) changes in the action potential duration, and (c) measurements with a K-selective micro-electrode. 3. The depolarization of the resting potential and the shortening of the action potential are present in approximately the same proportions during voltage-clamp induced extracellular K accumulation and during perfusion with a K-ricn Ringer solution but small consistent differences are noticed. 4. The measurements of the after-potential, the action potential shortening, and the K-electrode response were analysed as indicators of extracellular K+ activity and it was concluded that the after-potential provides the most convenient and reliable estimate of the absolute magnitude of the voltage-clamp induced extracellular K accumulation. 5. The depolarizing after-potentials decay more slowly than the hyperpolarizing after-potentials but it is found that this reflects the selectivity of the membrane to K+ concentrations as predicted by the Nernst or the Goldman equations. 6. Analysis of the redistribution of accumulated K+ from the decay of the after-potential suggests that the major part of the redistribution process can be described by a single time constant (2--4 sec). A much longer time constant is required for a smaller component of the 'tail' in order to bring [K]o to the normal resting state. 7. N-shaped relations similar to the 'steady state' current-voltage relation are obtained when the post-clamp after-potential, the action potential shortening, and the K-electrode response are plotted versus the clamped membrane potential. The maxima of these curves are located around -40 mV and the minima around -20 mV. 8. In spite of a significant outward membrane current (1--1.5 microamperemeter) in the minimum

  17. Cell-attached voltage-clamp and current-clamp recording and stimulation techniques in brain slices.

    PubMed

    Perkins, Katherine L

    2006-06-30

    Cell-attached recording provides a way to record the activity of - and to stimulate - neurons in brain slices without rupturing the cell membrane. This review uses theory and experimental data to address the proper application of this technique and the correct interpretation of the data. Voltage-clamp mode is best-suited for recording cell firing activity, and current-clamp mode is best-suited for recording resting membrane potential and synaptic potentials. The magnitude of the seal resistance determines what types of experiments can be accomplished with a cell-attached recording: a loose seal is adequate for recording action potential currents, and a tight seal is required for evoking action potentials in the attached cell and for recording resting and synaptic potentials. When recording action potential currents, if the researcher does not want to change the firing activity of the cell, then it is important that no current passes from the amplifier through the patch resistance. In order to accomplish this condition, the recording pipette should be held at the potential that gives a holding current of 0. An advantage of cell-attached current-clamp over whole-cell recording is that it accurately depicts whether a synaptic potential is hyperpolarizing or depolarizing without the risk of changing its polarity.

  18. Fabrication and characterization of GaN nanowire doubly clamped resonators

    SciTech Connect

    Maliakkal, Carina B. Mathew, John P.; Hatui, Nirupam; Rahman, A. Azizur; Deshmukh, Mandar M.; Bhattacharya, Arnab

    2015-09-21

    Gallium nitride (GaN) nanowires (NWs) have been intensely researched as building blocks for nanoscale electronic and photonic device applications; however, the mechanical properties of GaN nanostructures have not been explored in detail. The rigidity, thermal stability, and piezoelectric properties of GaN make it an interesting candidate for nano-electromechanical systems. We have fabricated doubly clamped GaN NW electromechanical resonators on sapphire using electron beam lithography and estimated the Young's modulus of GaN from resonance frequency measurements. For wires of triangular cross section with side ∼90 nm, we obtained values for the Young's modulus to be about 218 and 691 GPa, which are of the same order of magnitude as the values reported for bulk GaN. We also discuss the role of residual strain in the nanowire on the resonant frequency and the orientation dependence of the Young's modulus in wurtzite crystals.

  19. An experimental model of aortic surgery and the effect of Iloprost on lung injury.

    PubMed

    Iscan, Sahin; Huseyin, Serhat; Ozdemir, A Coskun; Yalta, Tulin; Yuksel, Volkan; Aksu, Volkan; Ege, Turan

    2013-08-01

    Ischemia/reperfusion (I/R) damage of the lung is a frequently encountered complication following aortic surgery. The aim of the present study is to investigate the histopathological effects of Iloprost on pulmonary damage developed after I/R. Twenty-four Sprague-Dawley rats were randomly divided into 3 groups. In the control group, aortas were not clamped. In the I/R group, aortas were occluded, and after 1 h of ischemia, clamps were removed. After 2 h of reperfusion period, lungs of the rats were extracted. In the I/R + Iloprost group after 1 h of ischemia, Iloprost infusion was initiated, and maintained for the duration of 2 h reperfusion period. For histopathological scoring, density of polymorphonuclear leucocytes, congestion, interstitial edema, and bleeding were semiquantitatively evaluated, and histopathological changes were scored. In the I/R group, multifocal-marked histopathological changes in 5 (62.5%), and multifocal-moderate histopathological changes in 3 (37.5%) rats were detected. In the I/R + Iloprost group, multifocal-moderate histopathological changes in 4 (50%), and multifocal-mild changes in 4 (50%) rats were detected. In the experimental rat model, administration of Iloprost has been shown to have preventive effects for pulmonary damage occurring after I/R generated by infrarenal aortic occlusion.

  20. Prognostic significance of mild aortic regurgitation in predicting mortality after transcatheter aortic valve replacement.

    PubMed

    Jones, Brandon M; Tuzcu, E Murat; Krishnaswamy, Amar; Popovic, Zoran; Mick, Stephanie; Roselli, Eric E; Gul, Sajjad; Devgun, Jasneet; Mistry, Sohi; Jaber, Wael A; Svensson, Lars G; Kapadia, Samir R

    2016-09-01

    Moderate to severe aortic regurgitation after transcatheter aortic valve replacement is associated with worse outcomes. The impact of mild aortic regurgitation has been less clear, possibly because of the broad categories that have been used in clinical trials, but holds increasing importance in the study of next-generation devices in low- and intermediate-risk cohorts. A more granular scheme, which is common in clinical practice and proposed for future trials, may add prognostic value. We evaluated all patients undergoing transfemoral transcatheter aortic valve replacement at the Cleveland Clinic from 2006 to 2012. The degree of aortic regurgitation after transcatheter aortic valve replacement was reported from the echocardiography database based on a clinical, transthoracic echocardiogram performed within 30 days of the procedure. Aortic regurgitation was finely discriminated on the basis of a multiwindow, multiparametric, integrative approach using our usual clinical scale: none, trivial to 1+, 1+, 1 to 2+, 2+, 2 to 3+, 3+, 3 to 4+, or 4+. There were 237 patients included in the analysis. By controlling for age, gender, Society of Thoracic Surgeons score, baseline ejection fraction, and aortic regurgitation before transcatheter aortic valve replacement, there was a significant increase in mortality for each half grade of aortic regurgitation compared with the complete absence of aortic regurgitation after transcatheter aortic valve replacement. The unit hazard ratio for each 1+ increase in aortic regurgitation after transcatheter aortic valve replacement was 2.26 (95% confidence interval, 1.48-3.43; P < .001) considering aortic regurgitation as a continuous variable. Other clinical variables did not significantly affect mortality. Even mild aortic regurgitation after transcatheter aortic valve replacement is associated with worse long-term mortality. There may be prognostic value in reporting milder categories of aortic regurgitation with more granular

  1. Visceral Infarction Following Aortic Surgery

    PubMed Central

    Johnson, Willard C.; Nabseth, Donald C.

    1974-01-01

    An experience with aortic surgery is reported which reveals that visceral ischemia is more frequent than expected and significantly contributes to operative mortality. Two of five deaths among 84 patients who had aorto-iliac occlusive disease and four of 40 deaths among 103 aneurysmectomies (both ruptured and elective) were related to visceral ischemia. A review of the literature reveals 99 cases of colonic ischemia in more than 6,100 cases of aortic surgery, an incidence of 1.5%. Only 10 cases of small bowel ischemia were recorded. The present experience with 9 cases of colon ischemia and one of small bowel ischemia is presented particularly with reference to pathophysiology and prevention. It is concluded that patients should be identified by appropriate angiography if considered a risk for visceral infarction, and, if present, visceral arterial reconstruction should be performed in addition to aortic reconstructive surgery. Colon infarction following aortic aneurysmal surgery is directly related to ligation of a patent IMA. Thus re-implantation of the patent IMA should be considered. ImagesFig. 1a. PMID:4277757

  2. Timing of umbilical cord clamping: new thoughts on an old discussion.

    PubMed

    Arca, Gemma; Botet, Francesc; Palacio, Montse; Carbonell-Estrany, Xavier

    2010-11-01

    The optimal time to clamp the umbilical cord in preterm and full-term neonates after birth continues to be a matter of debate. A review of randomised controlled trials comparing the effects of early versus late cord clamping on maternal and infant outcomes was performed to assess data in favor of immediate or delayed clamping. Although there is no conclusive evidence, delayed cord clamping seems to be beneficial in preterm and full-term neonates without compromising the initial postpartum adaptation phase or affecting the mother in the short term. However, further randomised clinical studies are needed to confirm the benefits of delayed cord clamping.

  3. Critical aortic stenosis and acute ascending aortic penetrating ulcer managed utilizing transapical TAVR and TEVAR.

    PubMed

    Allen, Keith B; Davis, J Russell; Cohen, David J

    2015-10-01

    Thoracic endovascular aortic repair (TEVAR) of acute ascending aortic pathology is feasible; however, the unique features of this aortic segment in addition to access challenges restricts its use to a select, high-risk subset of patients. With the advent of TAVR, large device delivery using transapical access has become a well-defined technique. We report a patient with critical aortic stenosis and an acute ascending aortic penetrating ulcer with tamponade managed successfully utilizing transapical TAVR and TEVAR. To our knowledge, this is the first reported case of a hybrid single-stage TAVR and ascending aortic TEVAR using transapical access.

  4. Percutaneous Aortic Balloon Valvuloplasty and Intracardiac Adrenaline in Electromechanical Dissociation as Bridge to Transcatheter Aortic Valve Implantation.

    PubMed

    Chaara, Jawad; Meier, Pascal; Ellenberger, Christophe; Gasche, Yvan; Bendjelid, Karim; Noble, Stephane; Roffi, Marco

    2015-07-01

    This report describes an emergent balloon aortic valvuloplasty (BAV) procedure performed under cardiopulmonary resuscitation in a 79-year-old man with severe symptomatic aortic stenosis (mean gradient 78 mm Hg, valve area 0.71 cm, and left ventricular ejection fraction 40%) awaiting surgery and who was admitted for heart failure rapidly evolving to cardiogenic shock and multiorgan failure. Decision was made to perform emergent BAV. After crossing the valve with a 6 French catheter, the patient developed an electromechanical dissociation confirmed at transesophageal echocardiography and cardiac arrest. Manual chest compressions were initiated along with the application of high doses of intravenous adrenaline, and BAV was performed under ongoing resuscitation. Despite BAV, transoesophageal echocardiography demonstrated no cardiac activity. At this point, it was decided to advance a pigtail catheter over the wire already in place in the left ventricle and to inject intracardiac adrenaline (1 mg, followed by 5 mg). Left ventricular contraction progressively resumed and, in the absence of aortic regurgitation, an intraaortic balloon pump was inserted. The patient could be weaned from intraaortic balloon pump and vasopressors on day 1, extubated on day 6, and recovered from multiorgan failure. In the absence of neurologic deficits, he underwent uneventful transcatheter aortic valve implantation on day 12 and was discharged to a cardiac rehabilitation program on day 30. At 3-month follow-up, he reported dyspnea NYHA class II as the only symptom.This case shows that severe aortic stenosis leading to electromechanical dissociation may be treated by emergent BAV and intracardiac administration of high-dose adrenaline. Intracardiac adrenaline may be considered in case of refractory electromechanical dissociation occurring in the cardiac catheterization laboratory.

  5. Effect of age and blood pressure on aortic size and stroke distance.

    PubMed Central

    Towfiq, B A; Weir, J; Rawles, J M

    1986-01-01

    The diameters of the ascending and descending aorta at the level of the carina were measured from computerised tomograms in 200 adults without cardiac or aortic disease. At all ages the ascending aorta had a greater cross sectional area than the descending aorta, and both areas increased significantly with age. The increase was proportionately greater in the descending than in the ascending aorta and the percentage changes were similar in males and females, the latter having a smaller mean descending aortic diameter. The extent of the increase in cross sectional area of the aorta is sufficient to explain the observed fall of stroke distance that occurs with age. The effect of changing blood pressure on aortic cross sectional area, and hence the relation between stroke distance and stroke volume, was calculated from published data on aortic compliance at different ages. Assuming constant peripheral resistance, stroke distance would change by 34, 82, and 94% for a 100% change of stroke volume at age 20, 50, and 80 respectively. At age 80 the aorta behaves like a rigid pipe but at age 20 its elasticity is such that constancy of aortic size cannot be assumed. Images Fig. 1 Fig. 2 PMID:3718794

  6. Clamping stiffness and its influence on load distribution between paired internal spinal fixation devices.

    PubMed

    Rohlmann, A; Calisse, J; Bergmann, G; Radvan, J; Mayer, H M

    1996-06-01

    The load distribution between two internal spinal fixation devices depends, besides other factors, on their stiffness. The stiffness ranges were determined experimentally for the clamps of the AO internal fixator with lateral nut and with posterior nut as well as for the clamps of the SOCON fixator. The stiffness of eight devices each differed by a factor of 3.1 for the clamp with lateral nut, by a factor of 1.5 for the clamp with posterior nut, and by a factor of 1.4 for the clamp of the SOCON fixator. For the AO clamp with lateral nut, the influence of the nut-tightening torque on the stiffness was determined. Using instrumented internal spinal fixation devices mounted to plastic vertebrae and simulating a corpectomy, the load distribution between the implants was measured for different tightening torques. It could be shown that, for the AO internal fixator whose clamps have a lateral nut, a nut-tightening torque > 5 Nm has only a negligible influence on load-sharing between the implants. Tooth damage occurs when the teeth of the clamp body and clamping jaw of the clamp with lateral nut do not gear together exactly, which leads to changes in the clamping stiffness and load-sharing between the two implants.

  7. [Early and long term results of mechanical aortic valve replacement at the Instituto Nacional del Torax in Chile].

    PubMed

    Villavicencio, Mauricio; Turner, Eduardo; Naranjo, Lorenzo

    2005-10-01

    Mechanical aortic valve replacement (AVR) results have been published extensively in industrialized countries. To assess our immediate and late results in patients subjected to AVR. We retrospectively studied 194 patients subjected to isolated AVR between 1995 and 2003. Mean age was 57 +/- 13 years and 119 (61%) were male. One hundred thirty nine (73%) were in functional class III-IV, 20 (10%) had a previous cardiac operation and 25 (13%) were operated as an emergency. Surgical indication was stenosis in 110 (58%), regurgitation in 49 (26%) and stenosis/regurgitation in 31 (16%). Etiology was bicuspid valve 56 (29%), degenerative lesions 55 (28%), rheumatic valve disease 38 (20%) and endocarditis 27 (14%). Medtronic Hall was the most common prosthesis used in 157 patients (81%). Mean cardiopulmonary bypass time 97 +/- 29 min and mean cross clamp time was 69 +/- 21 min. Operative mortality was 4.6% (3% in elective surgery, 16% in emergency surgery and 0% in reoperations). Follow-up was complete in 100% of cases, totalizing 636 patients-year. Survival was 91 +/- 2%, 80 +/- 4% and 73 +/- 6%, at 1, 5 and 7 years, respectively. Multivariate risk analysis identified renal failure and endocarditis as predictors of early and late mortality. During follow up, the linear incidence rate for hemorrhage was 3.29% /patients-year, thromboembolism 2.04% patients-year and endocarditis 1.1% patients-year. AVR has low overall and elective mortality. Midterm survival is good but linear event rates related to anticoagulant treatment are higher than those previously published in industrialized countries. Renal failure and endocarditis were risk factors for early and late death.

  8. Aortic biomechanics by magnetic resonance: early markers of aortic disease in Marfan syndrome regardless of aortic dilatation?

    PubMed

    Teixido-Tura, Gisela; Redheuil, Alban; Rodríguez-Palomares, Jose; Gutiérrez, Laura; Sánchez, Violeta; Forteza, Alberto; Lima, Joao A C; García-Dorado, David; Evangelista, Artur

    2014-01-15

    Previous studies demonstrated the usefulness of MRI in the evaluation of aortic biomechanics in Marfan patients with aortic dilatation. However, these parameters have not been well studied in earlier stages of aortic disease. The present work aimed to study aortic biomechanics: aortic distensibility (AD) and pulse wave velocity (PWV), by MRI in Marfan patients without advanced aortic disease. Eighty consecutive Marfan patients were compared with 36 age- and sex-matched controls. MRI images at the level of ascending, descending and abdominal aorta were used to determine AD and PWV. Marfan patients (27 men; age: 32.0 ± 10.5 years; mean aortic root diameter: 37.2 ± 4.6mm) had lower AD at all levels (ascending 2.6 ± 2.1 vs. 6.2 ± 3.7 mm Hg(-1)·10(-3), p<0.001; descending 3.1 ± 2.0 vs. 8.3 ± 4.2, p<0.001; and abdominal 4.5 ± 2.2 vs. 14.0 ± 5.2, p<0.001), higher aortic arch PWV (8.1 ± 6.5 vs. 4.3 ± 1.8m/s, p<0.01) and ascending-to-abdominal PWV (6.1 ± 3.0 vs. 4.7 ± 1.5m/s, p<0.01) compared with controls. Thirty-five Marfan patients had a non-dilated aortic root (mean aortic root diameter: 34.5 ± 3.8 mm). In multivariable analyses, after adjustment for age, pulse pressure and aortic dimensions, AD remained lower and PWV higher in Marfan patients; even Marfan patients with non-dilated aortic root showed impaired aortic biomechanics compared with controls. Z-score for ascending AD<-3.5 distinguished Marfan patients from controls with 82.5% sensitivity and 86.1% specificity. Aortic biomechanics by MRI were abnormal in the entire aorta in Marfan patients. Moreover, Marfan patients without dilated aortic root showed clear impairment of aortic biomechanics, which suggests that they may be used as early markers of aortic involvement in these patients. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  9. Decreased expression of fibulin-4 in aortic wall of aortic dissection.

    PubMed

    Huawei, P; Qian, C; Chuan, T; Lei, L; Laing, W; Wenlong, X; Wenzhi, L

    2014-02-01

    In this research, we will examine the expression of Fibulin-4 in aortic wall to find out its role in aortic dissection development. The samples of aortic wall were obtained from 10 patients operated for acute ascending aortic dissection and five patients for chronic ascending aortic dissection. Another 15 pieces of samples from patients who had coronary artery bypass were as controls. The aortic samples were stained with aldehyde magenta dyeing to evaluate the arrangement of elastic fibers. The Fibulin-4 protein and mRNA expression were both determined by Western blot and realtime quantitative polymerase chain reaction. Compared with the control group, both in acute and chronic ascending aortic dissection, elastic fiber fragments increased and the expression of fibulin-4 protein significantly decreased (P= 0.045 < 0.05). The level of fibulin-4 mRNA decreased in acute ascending aortic dissection (P= 0.034 < 0.05), while it increased in chronic ascending aortic dissection (P=0.004 < 0.05). The increased amounts of elastic fiber fragments were negatively correlated with the expression of fibulin-4 mRNA in acute ascending aortic dissection. In conclusion, in aortic wall of ascending aortic dissection, the expression of fibulin-4 protein decreased and the expression of fibulin-4 mRNA was abnormal. Fibulin-4 may play an important role in the pathogenesis of aortic dissection.

  10. M. tuberculosis Sliding β-Clamp Does Not Interact Directly with the NAD+ -Dependent DNA Ligase

    PubMed Central

    Kukshal, Vandna; Khanam, Taran; Chopra, Deepti; Singh, Nidhi; Sanyal, Sabyasachi; Ramachandran, Ravishankar

    2012-01-01

    The sliding β-clamp, an important component of the DNA replication and repair machinery, is drawing increasing attention as a therapeutic target. We report the crystal structure of the M. tuberculosis β-clamp (Mtbβ-clamp) to 3.0 Å resolution. The protein crystallized in the space group C2221 with cell-dimensions a = 72.7, b = 234.9 & c = 125.1 Å respectively. Mtbβ-clamp is a dimer, and exhibits head-to-tail association similar to other bacterial clamps. Each monomer folds into three domains with similar structures respectively and associates with its dimeric partner through 6 salt-bridges and about 21 polar interactions. Affinity experiments involving a blunt DNA duplex, primed-DNA and nicked DNA respectively show that Mtbβ-clamp binds specifically to primed DNA about 1.8 times stronger compared to the other two substrates and with an apparent Kd of 300 nM. In bacteria like E. coli, the β-clamp is known to interact with subunits of the clamp loader, NAD+ -dependent DNA ligase (LigA) and other partners. We tested the interactions of the Mtbβ-clamp with MtbLigA and the γ-clamp loader subunit through radioactive gel shift assays, size exclusion chromatography, yeast-two hybrid experiments and also functionally. Intriguingly while Mtbβ-clamp interacts in vitro with the γ-clamp loader, it does not interact with MtbLigA unlike in bacteria like E. coli where it does. Modeling studies involving earlier peptide complexes reveal that the peptide-binding site is largely conserved despite lower sequence identity between bacterial clamps. Overall the results suggest that other as-yet-unidentified factors may mediate interactions between the clamp, LigA and DNA in mycobacteria. PMID:22545130

  11. Umbilical cord clamping at birth--practice in Norwegian maternity wards.

    PubMed

    Lundberg, Camilla; Øian, Pål; Klingenberg, Claus

    2013-11-26

    The timing and practice used for umbilical cord clamping of neonates are controversial internationally as well as in Norway. We therefore wished to investigate routines and practices for umbilical cord clamping of neonates in Norway. A web-based questionnaire was sent to heads of departments of all maternity wards in Norway (n = 52). They were asked about their practice with regard to umbilical cord clamping of neonates and whether written routines had been prepared for this purpose. We defined early umbilical cord clamping as immediate or within 30 seconds and late clamping as ≥ 1 minute or not until pulsation in the umbilical cord had ceased. Fifty (96%) of the maternity institutions returned a completed questionnaire. Twelve institutions (24%) reported to clamp the umbilical cord of full-term neonates early, and 38 (76%) reported to practise late clamping. Nineteen maternity wards (38%) followed written routines for umbilical cord clamping of full-term neonates, and among these, early umbilical cord clamping was practised in nine (47%). In the 31 maternity wards that had no written routines, early umbilical cord clamping was practised in three (10%). Twenty-seven of the maternity wards reported that the child is placed on the maternal abdomen before clamping of the umbilical cord, 14 reported that the child commonly is held below the introitus before umbilical cord clamping, and the rest did not report any consistent practice. There is wide variation in the practice for umbilical cord clamping in Norwegian maternity wards, many of which have no written guidelines. We argue that national guidelines for umbilical cord clamping of neonates should be established.

  12. Moderate aortic enlargement and bicuspid aortic valve are associated with aortic dissection in Turner syndrome: report of the international turner syndrome aortic dissection registry.

    PubMed

    Carlson, Misty; Airhart, Nathan; Lopez, Leo; Silberbach, Michael

    2012-10-30

    Girls and women with Turner syndrome are at risk for aortic dissection and rupture. However, the size of the aorta and the clinical characteristics among those with Turner syndrome and dissection have received little attention. We obtained medical records from 20 individuals who voluntarily participated in the International Turner Syndrome Aortic Dissection Registry. Type A dissections occurred in 17 of 20 (85%) cases, and type B occurred in 3 cases of which 1 occurred after coarctation stent placement. Of those with spontaneous aortic dissections, 18 of 19 (95%) had an associated cardiac malformation that included a bicuspid aortic valve. In 1 individual there was no predisposing finding other than the presence of Turner syndrome. Associated pregnancy was documented in 1 of 19 (5%). More than half (13/19, 68%) came to medical attention >24 hours after the onset of symptoms. For those with type A dissections, the mean ascending aortic size index was 2.7±0.6 cm/m(2) (n=9). Aortic dissection in Turner syndrome occurs in young individuals at smaller aortic diameters than in the general population or other forms of genetically triggered aortopathy. The absence of aortic valve or other cardiac malformations appears to markedly reduce the risk of aortic dissection However, aortic dissection can occur in Turner syndrome without cardiac malformations or hypertension. Individuals with Turner syndrome who are >18 years of age with an ascending aortic size index >2.5 cm/m(2) should be considered for an aortic operation to prevent aortic dissection.

  13. Analysis of motion during the breast clamping phase of mammography.

    PubMed

    Ma, Wang Kei; McEntee, Mark F; Mercer, Claire; Kelly, Judith; Millington, Sara; Hogg, Peter

    2016-01-01

    To measure paddle motion during the clamping phase of a breast phantom for a range of machine/paddle combinations. A deformable breast phantom was used to simulate a female breast. 12 mammography machines from three manufacturers with 22 flexible and 20 fixed paddles were evaluated. Vertical motion at the paddle was measured using two calibrated linear potentiometers. For each paddle, the motion in millimetres was recorded every 0.5 s for 40 s, while the phantom was compressed with 80 N. Independent t-tests were used to determine differences in paddle motion between flexible and fixed, small and large, GE Senographe Essential (General Electric Medical Systems, Milwaukee, WI) and Hologic Selenia Dimensions paddles (Hologic, Bedford, MA). Paddle tilt in the medial-lateral plane for each machine/paddle combination was calculated. All machine/paddle combinations demonstrate highest levels of motion during the first 10 s of the clamping phase. The least motion is 0.17 ± 0.05 mm/10 s (n = 20) and the most motion is 0.51 ± 0.15 mm/10 s (n = 80). There is a statistical difference in paddle motion between fixed and flexible (p < 0.001), GE Senographe Essential and Hologic Selenia Dimensions paddles (p < 0.001). Paddle tilt in the medial-lateral plane is independent of time and varied from 0.04 ° to 0.69 °. All machine/paddle combinations exhibited motion and tilting, and the extent varied with machine and paddle sizes and types. This research suggests that image blurring will likely be clinically insignificant 4 s or more after the clamping phase commences.

  14. Analysis of motion during the breast clamping phase of mammography

    PubMed Central

    McEntee, Mark F; Mercer, Claire; Kelly, Judith; Millington, Sara; Hogg, Peter

    2016-01-01

    Objective: To measure paddle motion during the clamping phase of a breast phantom for a range of machine/paddle combinations. Methods: A deformable breast phantom was used to simulate a female breast. 12 mammography machines from three manufacturers with 22 flexible and 20 fixed paddles were evaluated. Vertical motion at the paddle was measured using two calibrated linear potentiometers. For each paddle, the motion in millimetres was recorded every 0.5 s for 40 s, while the phantom was compressed with 80 N. Independent t-tests were used to determine differences in paddle motion between flexible and fixed, small and large, GE Senographe Essential (General Electric Medical Systems, Milwaukee, WI) and Hologic Selenia Dimensions paddles (Hologic, Bedford, MA). Paddle tilt in the medial–lateral plane for each machine/paddle combination was calculated. Results: All machine/paddle combinations demonstrate highest levels of motion during the first 10 s of the clamping phase. The least motion is 0.17 ± 0.05 mm/10 s (n = 20) and the most motion is 0.51 ± 0.15 mm/10 s (n = 80). There is a statistical difference in paddle motion between fixed and flexible (p < 0.001), GE Senographe Essential and Hologic Selenia Dimensions paddles (p < 0.001). Paddle tilt in the medial–lateral plane is independent of time and varied from 0.04 ° to 0.69 °. Conclusion: All machine/paddle combinations exhibited motion and tilting, and the extent varied with machine and paddle sizes and types. Advances in knowledge: This research suggests that image blurring will likely be clinically insignificant 4 s or more after the clamping phase commences. PMID:26739577

  15. Nonlinear vibrations of fluid-filled clamped circular cylindrical shells

    NASA Astrophysics Data System (ADS)

    Karagiozis, K. N.; Amabili, M.; Païdoussis, M. P.; Misra, A. K.

    2005-12-01

    In this study, the nonlinear vibrations are investigated of circular cylindrical shells, empty or fluid-filled, clamped at both ends and subjected to a radial harmonic force excitation. Two different theoretical models are developed. In the first model, the standard form of the Donnell's nonlinear shallow-shell equations is used; in the second, the equations of motion are derived by a variational approach which permits the inclusion of constraining springs at the shell extremities and taking in-plane inertial terms into account. In both cases, the solution includes both driven and companion modes, thus allowing for a travelling wave in the circumferential direction; they also include axisymmetric modes to capture the nonlinear inward shell contraction and the correct type (softening) nonlinear behaviour observed in experiments. In the first model, the clamped beam eigenfunctions are used to describe the axial variations of the shell deformation, automatically satisfying the boundary conditions, leading to a 7 degree-of-freedom (dof) expansion for the solution. In the second model, rotational springs are used at the ends of the shell, which when large enough reproduce a clamped end; the solution involves a sine series for axial variations of the shell deformation, leading to a 54 dof expansion for the solution. In both cases the modal expansions satisfy the boundary conditions and the circumferential continuity condition exactly. The Galerkin method is used to discretize the equations of motion, and AUTO to integrate the discretized equations numerically. When the shells are fluid-filled, the fluid is assumed to be incompressible and inviscid, and the fluid structure interaction is described by linear potential flow theory. The results from the two theoretical models are compared with existing experimental data, and in all cases good qualitative and quantitative agreement is observed.

  16. Clamped seismic metamaterials: ultra-low frequency stop bands

    NASA Astrophysics Data System (ADS)

    Achaoui, Y.; Antonakakis, T.; Brûlé, S.; Craster, R. V.; Enoch, S.; Guenneau, S.

    2017-06-01

    The regularity of earthquakes, their destructive power, and the nuisance of ground vibration in urban environments, all motivate designs of defence structures to lessen the impact of seismic and ground vibration waves on buildings. Low frequency waves, in the range 1-10 Hz for earthquakes and up to a few tens of Hz for vibrations generated by human activities, cause a large amount of damage, or inconvenience; depending on the geological conditions they can travel considerable distances and may match the resonant fundamental frequency of buildings. The ultimate aim of any seismic metamaterial, or any other seismic shield, is to protect over this entire range of frequencies; the long wavelengths involved, and low frequency, have meant this has been unachievable to date. Notably this is scalable and the effects also hold for smaller devices in ultrasonics. There are three approaches to obtaining shielding effects: bragg scattering, locally resonant sub-wavelength inclusions and zero-frequency stop-band media. The former two have been explored, but the latter has not and is examined here. Elastic flexural waves, applicable in the mechanical vibrations of thin elastic plates, can be designed to have a broad zero-frequency stop-band using a periodic array of very small clamped circles. Inspired by this experimental and theoretical observation, all be it in a situation far removed from seismic waves, we demonstrate that it is possible to achieve elastic surface (Rayleigh) wave reflectors at very large wavelengths in structured soils modelled as a fully elastic layer periodically clamped to bedrock. We identify zero frequency stop-bands that only exist in the limit of columns of concrete clamped at their base to the bedrock. In a realistic configuration of a sedimentary basin 15 m deep we observe a zero frequency stop-band covering a broad frequency range of 0-30 Hz.

  17. Nanomechanics of PCNA: A protein-made DNA sliding clamp

    NASA Astrophysics Data System (ADS)

    Rydzewski, Jakub; Strzalka, Wojciech; Nowak, Wieslaw

    2015-08-01

    Proliferating Cell Nuclear Antigen (PCNA) is a homotrimeric DNA sliding clamp involved in DNA replication, repair and cell cycle control. Understanding determinants of mechanical stability of a PCNA monomer composed of two N- and C-terminal domains requires all-atom and coarse-grained steered molecular dynamics simulations. Three schemes of unfolding at a single molecule level indicate that the conserved curvature of the PCNA monomer is due to aggregation of side β-sheets. The force spectra suggest that rupturing an interface between the domains is less probable than opening an interface between the two monomers during PCNA loading onto DNA by Replication Factor C.

  18. Normal-Pressure Tests of Circular Plates with Clamped Edges

    NASA Technical Reports Server (NTRS)

    Mcpherson, Albert E; Ramberg, Walter; Levy, Samuel

    1942-01-01

    A fixture is described for making normal-pressure tests of flat plates 5 inches in diameter in which particular care was taken to obtain rigid clamping at the edges. Results are given for 19 plates, ranging in thickness form 0.015 to 0.072 inch. The center deflections and the extreme-fiber stresses at low pressures were found to agree with theoretical values; the center deflections at high pressures were 4 to 12 percent greater than the theoretical values. Empirical curves are derived of the pressure for the beginning of the permanent set as a function of the dimensions of the plate and the tensile properties of the material.

  19. [Time of cord clamping and neonatal complications, a prospective study].

    PubMed

    Rincón, D; Foguet, A; Rojas, M; Segarra, E; Sacristán, E; Teixidor, R; Ortega, A

    2014-09-01

    To assess the effects of early or late clamping of the umbilical cord in term newborns, assessing the levels of hemoglobin, hematocrit, and ferritin, and their correlation with some of the complications. A prospective study of healthy newborns at term or born by dystotic or eutocic delivery in our hospital between May 2009 until May 2010. Patients were assigned according to the time of clamping, group 1 (<60 seconds), group 2 (1 to<2 minutes), and group 3 (2 to 3 minutes). Laboratory tests were performed at birth and at 48 hours of life, assessing the levels of hemoglobin, hematocrit, ferritin, and bilirubin. The risk of polycythemia, respiratory distress syndrome, neonatal phototherapy or admission to the Intensive Care Unit and the hospital stay, were evaluated. A total of 242 patients were included: group 1 (g1=80), group 2 (g2=31) y group 3 (g3=131). The background maternal and neonatal characteristics were similar in all sets. The first test showed significant differences in ferritin levels in those infants with delayed clamping (g1: 111 mg/dl, g2: 125 mg/dl, g3: 173 mg/dl; p<0.01). In the second analysis the values of hemoglobin (g1: 17.3 g/dl, g2: 18.9 g/dl, g3: 19.2 g/dl; p<0.01), hematocrit (g1: 53.4%, g2: 58%, g3: 59%; p<0.01) and ferritin (g1: 254 mg/dl, g2: 254.7 mg/dl, g3: 313 mg/dl; p = 0.008) were statistically higher in this group. As regards complications, a significant increase was observed in the number of cases of polycythemia symptoms in group 3. The late cord clamping is associated with an increase in hematocrit, hemoglobin and ferritin at 48 hours of life, as well as an increased risk of polycythemia present with symptoms. Copyright © 2013 Asociación Española de Pediatría. Published by Elsevier Espana. All rights reserved.

  20. Timing of umbilical cord clamping and neonatal haematological status.

    PubMed

    Jaleel, Riffat; Deeba, Farah; Khan, Ayesha

    2009-07-01

    To determine the effect of delayed umbilical cord clamping on Hb (haemoglobin) and bilirubin levels of neonates and to identify newborn babies with anaemia and refer them for treatment. This Randomized Controlled Trial was conducted in the Department of Obstetrics and Gynaecology, Unit V, Dow Medical College and Lyari General Hospital and Department of Pathology, Lyari General Hospital, between 1st November, 2006 and 15th July, 2007. Patients admitted to labour ward were selected according to inclusion criteria of the study. They were randomly allocated to 2 groups. Group A included women in whom umbilical cord was clamped immediately after birth. In Group B, clamping was delayed until cessation of pulsations in the cord. After cutting the cord, sample of blood was collected from the cut end of cord of the newborn for Hb and bilirubin. After 6 hours of birth, another sample of blood was drawn from antecubital vein for serum bilirubin. Samples were sent to laboratory for analysis. All data were entered and analyzed using SPSS version 11. Two hundred women were studied, 100 in each of the 2 groups. Mean maternal Hb was 9.75 g/dl in Group A and 9.95 g/dl in Group B. The average neonatal Hb was 14.1 g/dl in Group A and 15.2 g/dl in Group B (p = 0.008). In all 49% neonates in Group A and 37% in Group B had Hb < 14 g/dl. Serum bilirubin values at birth and at 6 hours of birth were 1.8 mg/dl and 2.5 mg/dl for Group A and 1.9 mg/dl and 2.7 mg/dl for Group B, respectively. The difference in bilirubin after 6 hours in the 2 groups was insignificant (p = 0.186). Delayed umbilical cord clamping at birth seems to be safe and can be expected to reduce the prevalence of anaemic newborn babies in our community.

  1. Normal-pressure Tests of Circular Plates with Clamped Edges

    NASA Technical Reports Server (NTRS)

    Mcpherson, Albert E; Ramberg, Walter; Levy, Samuel

    1942-01-01

    A fixture is described for making normal-pressure tests of flat plates 5 inches in diameter in which particular care was taken to obtain rigid clamping at the edges. Results are given for 19 plates, ranging in thickness from 0.015 to 0.072 inch. The center deflections and the extreme-fiber stresses at low pressures were found to agree with theoretical values; the center deflections at high pressures were 4 to 12 percent greater than the theoretical values. Empirical curves are derived of the pressure for the beginning of permanent set as a function of the dimensions of the plate and the tensile properties of the material.

  2. From unwinding to clamping - the DEAD box RNA helicase family.

    PubMed

    Linder, Patrick; Jankowsky, Eckhard

    2011-07-22

    RNA helicases of the DEAD box family are present in all eukaryotic cells and in many bacteria and Archaea. These highly conserved enzymes are required for RNA metabolism from transcription to degradation and are therefore important players in gene expression. DEAD box proteins use ATP to unwind short duplex RNA in an unusual fashion and remodel RNA-protein complexes, but they can also function as ATP-dependent RNA clamps to provide nucleation centres that establish larger RNA-protein complexes. Structural, mechanistic and molecular biological studies have started to reveal how these conserved proteins can perform such diverse functions and how accessory proteins have a central role in their regulation.

  3. Measurement of effective aortic valve area using three-dimensional echocardiography in children undergoing aortic balloon valvuloplasty for aortic stenosis.

    PubMed

    Bharucha, Tara; Fernandes, Fernanda; Slorach, Cameron; Mertens, Luc; Friedberg, Mark Kevin

    2012-04-01

    Pressure gradient is used for timing of balloon aortic valvuloplasty for aortic stenosis (AS) in children, but does not correlate well with outcome and is limited if ventricular function is poor. In adults, effective orifice area (EOA) is used to assess AS severity, but EOA by continuity equation or 2D echo is unreliable in children. Three-dimensional echocardiography (3DE) may reliably assess EOA but has not been studied in children. We assessed measurement of aortic valve EOA by 3DE in children with AS before and after balloon aortic valvuloplasty and compared results with change in aortic valve gradient. 3DE was performed at time of catheterization before and after balloon aortic valvuloplasty. Using 3DE multiplanar review mode, valve annulus diameter, area, and EOA were measured and compared with change in aortic gradient and degree of aortic insufficiency. Twenty-four 3DE studies in 12 children (mean age 4.4 ± 5.0 years) were analyzed. EOA was measurable in all. Catheter peak gradient decreased from 45 ± 10 to 26 ± 17 mmHg (P = 0.0018). 3DE EOA increased after balloon aortic valvuloplasty (0.59 ± 0.52 cm(2) vs 0.80 ± 0.70 cm(2) ; P = 0.03), without change in valve diameter. EOA change correlated with change in peak (r = 0.77; P = 0.005) and mean (r = 0.60; P = 0.03) aortic valve gradient post balloon aortic valvuloplasty. 3DE facilitates EOA measurement in pediatric AS and correlates with change in aortic valve gradient after balloon valvuloplasty. © 2011, Wiley Periodicals, Inc.

  4. Evaluation of the CritiView in pig model of abdominal aortic occlusion and graded hemorrhage

    NASA Astrophysics Data System (ADS)

    Mayevsky, A.; Preisman, S.; Willenz, P. E.; Castel, D.; Perel, A.; Givony, D.; Dekel, N.; Oren, L.; Pewzner, E.

    2009-02-01

    We hypothesize that in the presence of reduced oxygen delivery and extraction, blood flow will be redistributed in order to protect the most vital organs (e.g., brain and heart) by increasing their regional blood flow, while O2 delivery to the less vital organs (e.g., GI tract or urethral wall) will diminish. Evaluation of mitochondrial function in vivo could be done by monitoring the oxidation reduction state of the respiratory chain. Thus, the NADH redox state of less vital organs could serve as an indicator of overall O2 imbalance as well as an endpoint of resuscitation. We have therefore tested, in a pig model, a new medical device providing real time data on NADH redox state and tissue blood flow- TBF This device contains a modified three way Foley catheter with a fiber optic probe which connects the measurement unit to the tested tissue. Female pigs underwent graded hemorrhage (GH) or Aortic clamping (AC). The main effects of GH started when blood volume decreased by 30%. At 40% blood loss, minimal levels of TBF were correlated to the maximal NADH levels. The values of the 2 parameters returned to baseline after retransfusion of the shed blood. Aortic clamping led to significant decrease in TBF while NADH levels increased. After aortic declamping the parameters recovered to normal values. Due to the short length of the urethra in female pigs and the instable contact between the probe and the tissue, inconsistency of the responses was observed. Our preliminary results show that the CritiView may be a useful tool for the detection of body O2 imbalance.

  5. Temporary extracorporeal axillo-iliac vascular prosthesis shunt in open repair of a pararenal aortic aneurysm

    PubMed Central

    Dregelid, Einar

    2013-01-01

    INTRODUCTION When a long aortic clamp time is expected or when upper body to lower body collateral arteries are sparse, temporary lower body perfusion may be needed to reduce ischemic injury during supraceliac clamping in open repair of pararenal aortic aneurysms. The use of conventional extracorporeal perfusion techniques carry extra risks and is not in the armamentarium of most vascular surgeons. An axillo-femoral or -iliac shunt using a vascular prosthesis does not require the same degree of anticoagulation and causes less activation of blood components. PRESENTATION OF CASE A patient, who had extensive vascular stenotic disease and large bowel ischemia, was operated on for a pararenal aortic aneurysm while the lower body was perfused via a temporary extracorporeal vascular prosthesis axillo-iliac shunt. Copious backbleeding encountered while suturing the proximal anastomosis testified to the efficacy of the temporary shunt. A left hemicolectomy had to be performed for gangrene of the sigmoid colon and he needed 2 days of respiratory support; otherwise the postoperative course was uneventful. DISCUSSION In our case more ischemic injury than that observed might have been expected without the temporary bypass but significant backbleeding may have negated some of the beneficial effect of the shunt. CONCLUSION A temporary axillo-femoral or -iliac shunt prevents lower limb ischemia and provides an ample amount of collateral blood flow to the torso. It does not need to be buried subcutaneously as previously described. Occlusive balloons should be used where possible to prevent backbleeding and to further increase available collateral blood supply. PMID:23500740

  6. 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.

  7. [Surgical technique of aortic valve replacement for small aortic annulus in elderly patients].

    PubMed

    Hata, T; Fujiwara, K; Furukawa, H; Tsushima, Y; Yoshitaka, H; Kuinose, M; Minami, H; Ishida, A; Tamura, K; Totsugawa, T; Kanemitsu, H; Ozawa, M

    2006-04-01

    Recent reports have shown that aortic valve replacement in elderly patients over 65 years with atherosclerotic aortic stenosis and a small aortic annulus is possible by using a small sized bioprosthesis (Carpentier-Edwards pericardial valve). Here we present out surgical technique. Firstly, the native calcified aortic valve was removed completely to gain total exposure of the surrounding aortic root and sinus of Valsalva like Bentall procedure. Secondly, a small sized bioprosthesis was implanted with intermittent noneverting mattress 2-0 sutures with spaghetti and small polytetrafluoroethylene (PTFE) felt. Aortic annulus is the dilated by inserting Hegar dilator sizing from 25 to 27 mm. Therefore, aortic valve replacement for small aortic annulus in intra- or supra-annular position should be easily accomplished. Good surgical results and hemodynamic state were achieved in 25 consecutive cases using this technique.

  8. Hypertensive Emergency in Aortic Dissection and Thoracic Aortic Aneurysm—A Review of Management

    PubMed Central

    Gupta, Prateek K.; Gupta, Himani; Khoynezhad, Ali

    2009-01-01

    Over the last few decades, treatment for aortic dissection and thoracic aortic aneurysms has evolved significantly with improvement in outcomes. Treatment paradigms include medical, endovascular and surgical options. As aortic dissection presents as a hypertensive emergency, diligent control of BP is of utmost importance in order to reduce the progression of dissection with possible aortic branch malperfusion. Treatment should begin on arrival to the emergency department and continues in the intensive care unit, endovascular suite or the operating room. Novel antihypertensive medications with improved pharmacological profile and improved surgical techniques, have improved the prognosis of patients with aortic aneurysm and/or aortic dissection. Nevertheless, morbidity and mortality remain high and hypertensive emergency poses a significant challenge in aortic dissection and thoracic aortic aneurysms. PMID:27713224

  9. Reproducibility of aortic pulsatility measurements from ECG-gated abdominal CTA in patients with abdominal aortic aneurysms

    NASA Astrophysics Data System (ADS)

    Manduca, Armando; Fletcher, Joel G.; Wentz, Robert J.; Shields, Raymond C.; Vrtiska, Terri J.; Siddiki, Hassan; Nielson, Theresa

    2009-02-01

    Purpose: ECG-gated abdominal CT angiography with reconstruction of multiple, temporally overlapping CT angiography datasets has been proposed for measuring aortic pulsatility. The purpose of this work is to develop algorithms to segment the aorta from surrounding structures from CTA datasets across cardiac phases, calculate registered centerlines and measurements of regional aortic pulsatility in patients with AAA, and to assess the reproducibility of these measurements. Methods: ECG-gated CTA was performed with a temporal resolution of 165 ms, reconstructed to 1 mm slices ranging at 14 cardiac phase points. Data sets were obtained from 17 patients on which two such scans were performed 6 to 12 months apart. Automated segmentation, centerline generation, and registration of centerlines between phases was performed, followed by calculation of cross-sectional areas and regional and local pulsatility. Results: Pulsatility calculations for the supraceliac region were very reproducible between earlier and later scans of the same patient, with average differences less than 1% for pulsatility values ranging from 2% to 13%. Local radial pulsatilities were also reproducible to within ~1%. Aneurysm volume changes between scans can also be quantified. Conclusion: Automated segmentation, centerline generation, and registration of temporally resolved CTA datasets permit measurements of regional changes in cross-sectional area over the course of the cardiac cycle (i.e., regional aortic pulsatility). These measurements are reproducible between scans 6-12 months apart, with differences in aortic areas reflecting both aneurysm remodeling and changes in blood pressure. Regional pulsatilities ranged from 2 to 13% but were reproducible at the 1% level.

  10. The Relationship between Tension and Length of the Aortic Adventitia Resected from the Aortic Wall of Acute Aortic Dissection

    PubMed Central

    Kitano, Mitsuru; Teranishi, Hiroo; Kudo, Masahumi; Matsuura, Makoto

    2014-01-01

    Objective: To our knowledge, no previous study has described the measurement of the tensile strength of the human aortic adventitia. In the present study, we examined the relationship between the tension and length of the aortic adventitia resected from the aortic wall of patients with acute aortic dissection. Methods: We obtained rectangular specimens from the aortic adventitia that was resected in patients with acute aortic dissection during surgery. The specimens were placed on a tension meter (Digital Force Gauge FGS-10, SHIMPO, Kyoto, Japan) within 15 min after resection and stretched until they were pulled apart, and the tension and length were recorded. Results: We obtained 18 specimens during surgery from 11 cases of acute aortic dissection. When the specimen was being pulled apart, the mean tension recorded was 10.2 ± 4.9 N/cm specimen width, whereas the mean elongated length recorded was 4.2 ± 1.1 mm/cm specimen length. Discussion: We determined that the aortic adventitia is elastic and expandable up to 140% of its original length. This indicates that dilation of the aorta to >4.2 cm in diameter may result in a rupture if the original aortic diameter prior to dissection was 3 cm. (*English translation of J Jpn Coll Angiol 2013; 53: 77-81) PMID:25298826

  11. Severe Aortic Stenosis Associated with Unicommissural Unicuspid Aortic Valve in a Middle Aged Male

    PubMed Central

    Kwon, Hee-Jin; Kim, Song Soo; Sun, Byung Joo; Jin, Sun Ah; Kim, Jun-Hyung; Lee, Jae-Hwan; Choi, Siwan; Jeong, Jin-Ok; Seong, In-Whan

    2016-01-01

    Unicuspid aortic valve (UAV) is an extremely rare form of congenital aortic valvular abnormality. Although UAV shows similar clinical characteristics to bicuspid aortic valve, the clinical symptoms develop at earlier age and progress at a faster pace in UAV. In this report, we are presenting a 42-year-old male with severe aortic stenosis associated with unicommissural UAV. The patients underwent a successful Bentall operation. PMID:27721957

  12. Aortic-Brachial Pulse Wave Velocity Ratio: A Blood Pressure-Independent Index of Vascular Aging.

    PubMed

    Fortier, Catherine; Sidibé, Aboubacar; Desjardins, Marie-Pier; Marquis, Karine; De Serres, Sacha A; Mac-Way, Fabrice; Agharazii, Mohsen

    2017-01-01

    Aortic stiffness, a cardiovascular risk factor, depends on the operating mean arterial pressure (MAP). The impact of aortic stiffness on cardiovascular outcomes is proposed to be mediated by the attenuation or the reversal of the arterial stiffness gradient. We hypothesized that arterial stiffness gradient is less influenced by changes in MAP. We aimed to study the relationship between MAP and aortic stiffness, brachial stiffness, and arterial stiffness gradient. In a cross-sectional study of a dialysis cohort (group A, n=304) and a cohort of hypertensive or kidney transplant recipient with an estimated glomerular filtration rate of >45 mL/min/1.73 m(2) (group B, n=114), we assessed aortic and brachial stiffness by measuring carotid-femoral and carotid-radial pulse wave velocities (PWV). We used aortic-brachial PWV ratio as a measure of arterial stiffness gradient. Although there was a positive relationship between MAP and carotid-femoral PWV (R(2)=0.10 and 0.08; P<0.001 and P=0.003) and MAP and carotid-radial PWV (R(2)=0.22 and 0.12; P<0.001 and P<0.001), there was no statistically or clinically significant relationship between MAP and aortic-brachial PWV ratio (R(2)=0.0002 and 0.0001; P=0.8 and P=0.9) in group A and B, respectively. Dialysis status and increasing age increased the slope of the relationship between MAP and cf-PWV. However, we found no modifying factor (age, sex, dialysis status, diabetes mellitus, cardiovascular disease, and class of antihypertensive drugs) that could affect the lack of relationship between MAP and aortic-brachial PWV ratio. In conclusion, these results suggest that aortic-brachial PWV ratio could be considered as a blood pressure-independent measure of vascular aging. © 2016 American Heart Association, Inc.

  13. Aortic Stenosis: Pathophysiology, Diagnosis, and Therapy.

    PubMed

    Joseph, Jessica; Naqvi, Syed Yaseen; Giri, Jay; Goldberg, Sheldon

    2017-03-01

    The incidence of aortic stenosis increases with age, affecting up to 10% of the population by the eighth decade. Once symptoms develop, aortic stenosis is rapidly fatal. Proper management requires an understanding of the physiology and criteria used to define disease severity. There is no effective pharmacologic treatment. Surgical aortic valve replacement has been the gold standard treatment for decades. However, over the last 10 years transcatheter aortic valve replacement has emerged as an attractive, less-invasive option for appropriately selected patients. Refinements in valve design and delivery systems have led to widespread use of this breakthrough technology in selected patients. We review the pathophysiology, criteria for valve replacement, and the results of the trials comparing transcatheter aortic valve replacement with surgical aortic valve replacement.

  14. Delayed Umbilical Cord Clamping in the 21st Century: Indications for Practice.

    PubMed

    Bayer, Kimberly

    2016-02-01

    Health care providers have debated the timing of umbilical cord clamping since the days of Aristotle. Delayed cord clamping was the mainstay of practice until about the 1950s when it was changed to immediate clamping on the basis of a series of blood volume studies combined with the introduction of active management of the third stage of labor. However, in recent years, several systematic reviews advise that delayed cord clamping should be used in all births for at least 30 to 60 seconds. The purpose of this article is to discuss the physiology of umbilical cord clamping, the potential benefits and adverse effects of delayed cord clamping, and how this affects the advanced practice nurse. A search of PubMed, Cochrane Reviews, and Clinical Key was used to find relevant research on the topic of umbilical cord clamping. Potential benefits of delayed cord clamping include decreased frequency of iron-deficiency anemia in the first year of life with improved neurodevelopmental outcomes in term infants, reduced need for blood transfusions, possible autologous transfusion of stem cells, and a decreased incidence of intraventricular hemorrhage. Apprehension exists regarding the feasibility of the practice as well as the potential hindrance of immediate resuscitation. There is a need to begin to look for populations for which delayed cord clamping can be implemented. Recommendations are inconsistent on the patient population and timing; therefore, further studies are needed to understand the multiple variables that affect timing of umbilical cord clamping.

  15. Randomised trial of cord clamping and initial stabilisation at very preterm birth.

    PubMed

    Duley, Lelia; Dorling, Jon; Pushpa-Rajah, Angela; Oddie, Sam J; Yoxall, Charles William; Schoonakker, Bernard; Bradshaw, Lucy; Mitchell, Eleanor J; Fawke, Joe Anthony

    2017-09-18

    For very preterm births, to compare alternative policies for umbilical cord clamping and immediate neonatal care. Parallel group randomised (1:1) trial, using sealed opaque numbered envelopes. Eight UK tertiary maternity units. 261 women expected to have a live birth before 32 weeks, and their 276 babies. Cord clamping after at least 2 min and immediate neonatal care with cord intact, or clamping within 20 s and immediate neonatal care after clamping. Intraventricular haemorrhage (IVH), death before discharge. 132 women (137 babies) were allocated clamping ≥2 min and neonatal care cord intact, and 129 (139) clamping ≤20 s and neonatal care after clamping; six mother-infant dyads were excluded (2, 4) as birth was after 35(+6) weeks, one withdrew (death data only available) (0, 1). Median gestation was 28.9 weeks for those allocated clamping ≥2 min, and 29.2 for those allocated clamping ≤20 s. Median time to clamping was 120 and 11 s, respectively. 7 of 135 infants (5.2%) allocated clamping ≥2 min died and 15 of 135 (11.1%) allocated clamping ≤20 s; risk difference (RD) -5.9% (95% CI -12.4% to 0.6%). Of live births, 43 of 134 (32%) had IVH vs 47 of 132 (36%), respectively; RD -3.5% (-14.9% to 7.8%). There were no clear differences in other outcomes for infants or mothers. This is promising evidence that clamping after at least 2 min and immediate neonatal care with cord intact at very preterm birth may improve outcome; a large trial is urgently needed. ISRCTN 21456601. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  16. Surgical treatment of inflammatory abdominal aortic aneurysms: Outcome and predictors analysis

    PubMed Central

    Nuellari, Edmond; Esposito, Giampiero; Kuci, Saimir; Kapedani, Edmond

    2014-01-01

    Objectives The aim of this study is to report our experience on the postoperative outcome of surgical treatment of inflammatory abdominal aortic aneurysm (IAAA). Materials and Methods Between 1997–2014, 35 patients with IAAA underwent surgery. The mean age was 63 ± 18 years. Chronic renal failure was identified in 11 (31.4%) patients and confirmed ischemic heart disease in 15 (43%) patients. The mean aortic aneurysm diameter was 68 ± 25 mm. The abdominal aorta was clamped above the renal arteries in 6 (17%) patients. Results The hospital mortality was 5.7% (2 patients). Three patients developed an aortic pseudoaneurysm and underwent a redo operation. Another patient developed a femoral anastomotic pseudoaneurysm 7 years after operation and he was treated surgically. The actuarial free-reoperation actuarial survival at 1, 5 and 7 years was 94%, 62% and 50%, respectively. The Cox model revealed the delta erythrocyte sedimentation rate (p = 0.002), ischemic heart disease (p = 0.006) and renal failure (p = 0.036) as strong predictors for poor overall outcome. Conclusion Early postoperative outcome in terms of mortality and morbidity seems acceptable, however, patients with IAAA have an increased risk for reoperation due to pseudonaneurysm formation. Strong predictors for poor overall outcome seem to be the elevated erythrocyte sedimentation rate, ischemic heart disease and chronic renal failure. PMID:25243075

  17. Surgical Treatment of Inflammatory Abdominal Aortic Aneurysms: Outcome and Predictors Analysis

    PubMed Central

    Nuellari, Edmond; Prifti, Edvin; Esposito, Giampiero; Kapedani, Edmond

    2014-01-01

    Objectives: The aim of this study is to report our experience on the postoperative outcome of surgical treatment of inflammatory abdominal aortic aneurysm (IAAA). Materials and Methods: Between 1997-2014, 35 patients with IAAA underwent surgery. The mean age was 63+/-18years. Chronic renal failure was identified in 11(31.4%)patients and confirmed ischemic heart disease in 15(43%)patients. The mean aortic aneurysm diameter was 68+/-25mm. The abdominal aorta was clamped above the renal arteries in 6 (17%) patients. Results: The hospital mortality was 5.7% (2 patients). Three patients developed an aortic pseudoaneurysm and underwent a redo operation. Another patient developed a femoral anastomotic pseudoaneurysm 7 years after operation and he was treated surgically. The actuarial free-reoperation actuarial survival at 1, 5 and 7 years was 94%, 62% and 50% respectively. The Cox model revealed the delta ESR (p=0.002), ischemic heart disease (p=0.006) and renal failure (p=0.036) as strong predictors for poor overall outcome. Conclusion: Early postoperative outcome in terms of mortality and morbidity seems acceptable, however patients with IAAA have an increased risk for reoperation due to pseudonaneurysm formation. Strong predictors for poor overall outcome seems to be the elevated erythrocyte sedimentation rate, ischemic heart disease and chronic renal failure. PMID:25568545

  18. Do collagen-impregnated knitted Dacron grafts reduce the need for transfusion in infrarenal aortic reconstruction?

    PubMed

    Barral, X; Gay, J L; Favre, J P; Gournier, J P

    1995-07-01

    The purpose of this study was to evaluate the benefits of collagen-impregnated Dacron grafts in patients undergoing infrarenal aortic reconstruction. We therefore prospectively compared two consecutive series of patients undergoing infrarenal aortic reconstruction with Dacron grafts between January 1991 and December 1992. The first group (group A) included 83 high-density knitted prosthetic grafts (Dialine I), whereas the second included 82 grafts of the same type but impregnated with collagen (Dialine II). The two groups were comparable with regard to age, sex, and operative risk factors. They were also comparable in terms of the proportion of patients with occlusive disease or aneurysms, that is, there were 39 and 36 patients with occlusive disease and 44 and 46 patients with aneurysms in groups A and B, respectively. The type of bypass was similar in both groups with 17 and 19 tubular grafts and 66 and 63 bifurcated grafts being inserted in groups A and B, respectively. Thirteen parameters were studied and compared within each group including (1) number of infected grafts, (2) number of postoperative occlusions, (3) maximum postoperative temperature, (4) number of positive postoperative blood cultures, (5) number of postoperative deaths, (6) intraoperative and (7) postoperative quantities of blood transfused, (8) difference between pre- and postoperative hemoglobin concentrations, (9) difference between pre- and postoperative fibrinogen levels, (10) difference between pre- and postoperative platelet counts, (11) duration of aortic clamping, (12) date of return of intestinal function, and (13) mean duration of pre- and postoperative hospital stays.(ABSTRACT TRUNCATED AT 250 WORDS)

  19. Voltage and Current Clamp Transients with Membrane Dielectric Loss

    PubMed Central

    Fitzhugh, R.; Cole, K. S.

    1973-01-01

    Transient responses of a space-clamped squid axon membrane to step changes of voltage or current are often approximated by exponential functions of time, corresponding to a series resistance and a membrane capacity of 1.0 μF/cm2. Curtis and Cole (1938, J. Gen. Physiol. 21:757) found, however, that the membrane had a constant phase angle impedance z = z1(jωτ)-α, with a mean α = 0.85. (α = 1.0 for an ideal capacitor; α < 1.0 may represent dielectric loss.) This result is supported by more recently published experimental data. For comparison with experiments, we have computed functions expressing voltage and current transients with constant phase angle capacitance, a parallel leakage conductance, and a series resistance, at nine values of α from 0.5 to 1.0. A series in powers of tα provided a good approximation for short times; one in powers of t-α, for long times; for intermediate times, a rational approximation matching both series for a finite number of terms was used. These computations may help in determining experimental series resistances and parallel leakage conductances from membrane voltage or current clamp data. PMID:4754194

  20. The human dynamic clamp as a paradigm for social interaction.

    PubMed

    Dumas, Guillaume; de Guzman, Gonzalo C; Tognoli, Emmanuelle; Kelso, J A Scott

    2014-09-02

    Social neuroscience has called for new experimental paradigms aimed toward real-time interactions. A distinctive feature of interactions is mutual information exchange: One member of a pair changes in response to the other while simultaneously producing actions that alter the other. Combining mathematical and neurophysiological methods, we introduce a paradigm called the human dynamic clamp (HDC), to directly manipulate the interaction or coupling between a human and a surrogate constructed to behave like a human. Inspired by the dynamic clamp used so productively in cellular neuroscience, the HDC allows a person to interact in real time with a virtual partner itself driven by well-established models of coordination dynamics. People coordinate hand movements with the visually observed movements of a virtual hand, the parameters of which depend on input from the subject's own movements. We demonstrate that HDC can be extended to cover a broad repertoire of human behavior, including rhythmic and discrete movements, adaptation to changes of pacing, and behavioral skill learning as specified by a virtual "teacher." We propose HDC as a general paradigm, best implemented when empirically verified theoretical or mathematical models have been developed in a particular scientific field. The HDC paradigm is powerful because it provides an opportunity to explore parameter ranges and perturbations that are not easily accessible in ordinary human interactions. The HDC not only enables to test the veracity of theoretical models, it also illuminates features that are not always apparent in real-time human social interactions and the brain correlates thereof.

  1. Image processing techniques in computer-assisted patch clamping

    NASA Astrophysics Data System (ADS)

    Azizian, Mahdi; Patel, Rajni; Gavrilovici, Cezar; Poulter, Michael O.

    2010-02-01

    Patch clamping is used in electrophysiology to study single or multiple ion channels in cells. Multiple micropipettes are used as electrodes to collect data from several cells. Placement of these electrodes is a time consuming and complicated task due to the lack of depth perception, limited view through the microscope lens and the possibility of collisions between micro-pipettes. To aid in this process, a computer-assisted approach is developed using image processing techniques applied to images obtained through the microscope. Image processing algorithms are applied to perform autofocusing, relative depth estimation, distance estimation and tracking of the micro-pipettes in the images without making any major changes in the existing patch clamp equipment. An autofocusing algorithm with a micrometer precision is developed and the relative depth estimation is performed based on autofocusing. A micro-pipette tip detection algorithm is developed which can be used to initialize or reset the tracking algorithm and to calibrate the system by registering the relative image and micro-manipulator coordinates. An image-based tracking algorithm is also developed to track a micro-pipette tip in real time. The real-time tracking data is then used for visual servoing the micro-pipette tips and updating the calibration information.

  2. Binding inhibitors of the bacterial sliding clamp by design.

    PubMed

    Wijffels, Gene; Johnson, Wynona M; Oakley, Aaron J; Turner, Kathleen; Epa, V Chandana; Briscoe, Susan J; Polley, Mitchell; Liepa, Andris J; Hofmann, Albert; Buchardt, Jens; Christensen, Caspar; Prosselkov, Pavel; Dalrymple, Brian P; Alewood, Paul F; Jennings, Philip A; Dixon, Nicholas E; Winkler, David A

    2011-07-14

    The bacterial replisome is a target for the development of new antibiotics to combat drug resistant strains. The β(2) sliding clamp is an essential component of the replicative machinery, providing a platform for recruitment and function of other replisomal components and ensuring polymerase processivity during DNA replication and repair. A single binding region of the clamp is utilized by its binding partners, which all contain conserved binding motifs. The C-terminal Leu and Phe residues of these motifs are integral to the binding interaction. We acquired three-dimensional structural information on the binding site in β(2) by a study of the binding of modified peptides. Development of a three-dimensional pharmacophore based on the C-terminal dipeptide of the motif enabled identification of compounds that on further development inhibited α-β(2) interaction at low micromolar concentrations. We report the crystal structure of the complex containing one of these inhibitors, a biphenyl oxime, bound to β(2), as a starting point for further inhibitor design.

  3. Umbilical cord clamping and preterm infants: a randomised trial.

    PubMed Central

    Kinmond, S; Aitchison, T C; Holland, B M; Jones, J G; Turner, T L; Wardrop, C A

    1993-01-01

    OBJECTIVE--To investigate the clinical effects of regulating umbilical cord clamping in preterm infants. DESIGN--A prospective randomised study. SETTING--The Queen Mother's Hospital, Glasgow. SUBJECTS--36 vaginally delivered infants over 27 and under 33 weeks' gestation. INTERVENTION--Holding the infant 20 cm below the introitus for 30 seconds before clamping the umbilical cord ("regulated" group, 17 patients), or conventional management ("random" group, 19 patients). MAIN OUTCOME MEASURES--Initial packed cell volume, peak serum bilirubin concentrations, red cell transfusion requirements, and respiratory impairment (assessed by ventilatory requirements, arterial-alveolar oxygen tension ratio over the first day in ventilated infants, and duration of dependence on supplemental oxygen). RESULTS--There were statistically significant differences between the two groups in mean initial packed cell volume (regulated group 0.564, random group 0.509) and median red cell transfusion requirements (regulated group zero, random group 23 ml/kg). 13 infants from each group underwent mechanical ventilation and showed significant differences in mean minimum arterial-alveolar oxygen tension ratio on the first day (regulated group 0.42, random group 0.22) and in median duration of dependence on supplemental oxygen (regulated group three days, random group 10 days). Differences in final outcome measures such as duration of supplemental oxygen dependence and red cell transfusion requirements were mediated primarily through arterial-alveolar oxygen tension ratio and also packed cell volume. CONCLUSIONS--This intervention at preterm deliveries produces clinical and economic benefits. PMID:8443480

  4. Clamping of fine Kirschner wires in external fixators.

    PubMed

    Zamani, Ahmad R; Oyadiji, S Olutunde

    2016-11-01

    In Ilizarov circular (ring) external fixators, fine Kirschner wires are used to fix the bone to the fixator. Clamping of the wires to the rings with different bolt torques has been studied. However, the relation between the bolt torque and the fixation load applied to the wire was not investigated. In this work, finite element method is used to address this problem. Here, a fully three-dimensional model of the wire fixation assembly was built, with geometric details like threads on the bolt to produce a realistic simulation of the clamping of the wire. Both cannulated and slotted bolt types were studied and values of 0.2, 0.25, 0.3 and 0.45 were used for coefficient of friction. A torque was applied to the nut while the ring section and bolt kept in place. The results for bolt load, nut rotation as well as axial and radial wire deformations were obtained. The results demonstrated a linear relation between the bolt load and the bolt torque. The coefficient of this relationship was shown to be inversely proportional to the coefficient of friction. For all results, the bolt load (N) was approximately 124 times the bolt torque (N m) divided by the friction coefficient. The results highlighted the difference between the cannulated and the slotted bolts in terms of their grip on the wire.

  5. Aortic root vasculitis associated with Cogan's syndrome.

    PubMed

    Gasparovic, Hrvoje; Djuric, Zeljko; Bosnic, Dubravka; Petricevic, Mate; Brida, Margita; Dotlic, Snjezana; Biocina, Bojan

    2011-07-01

    Cogan's syndrome is characterized by nonsyphilitic interstitial keratitis and an audiovestibular disorder resembling Meniere disease. We report a patient with progressive congestive heart failure due to massive aortic and mitral insufficiency coupled with aortitis leading to an ascending aortic aneurysm. The patient underwent successful aortic root replacement and mitral valve repair. Copyright © 2011 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  6. Traumatic aortic incompetence following road traffic accident

    PubMed Central

    Irving, J. B.

    1974-01-01

    This case report describes the presentation and treatment of a case of aortic incompetence, resulting from a road traffic accident. The relevant literature is briefly reviewed. Aortic incompetence due to trauma has been described following non-penetrating chest injuries, such as kicks from horses (Barie, 1881), falls from heights and crushing accidents (Kissane, Koons and Clark, 1948; Levine, Roberts and Morrow, 1962). Despite the frequency of road traffic accidents, there have been no recent reports of traumatic aortic valve damage. PMID:4467876

  7. Association Between Gout and Aortic Stenosis.

    PubMed

    Chang, Kevin; Yokose, Chio; Tenner, Craig; Oh, Cheongeun; Donnino, Robert; Choy-Shan, Alana; Pike, Virginia C; Shah, Binita D; Lorin, Jeffrey D; Krasnokutsky, Svetlana; Sedlis, Steven P; Pillinger, Michael H

    2017-02-01

    An independent association between gout and coronary artery disease is well established. The relationship between gout and valvular heart disease, however, is unclear. The aim of this study was to assess the association between gout and aortic stenosis. We performed a retrospective case-control study. Aortic stenosis cases were identified through a review of outpatient transthoracic echocardiography (TTE) reports. Age-matched controls were randomly selected from patients who had undergone TTE and did not have aortic stenosis. Charts were reviewed to identify diagnoses of gout and the earliest dates of gout and aortic stenosis diagnosis. Among 1085 patients who underwent TTE, 112 aortic stenosis cases were identified. Cases and nonaortic stenosis controls (n = 224) were similar in age and cardiovascular comorbidities. A history of gout was present in 21.4% (n = 24) of aortic stenosis subjects compared with 12.5% (n = 28) of controls (unadjusted odds ratio 1.90, 95% confidence interval 1.05-3.48, P = .038). Multivariate analysis retained significance only for gout (adjusted odds ratio 2.08, 95% confidence interval 1.00-4.32, P = .049). Among subjects with aortic stenosis and gout, gout diagnosis preceded aortic stenosis diagnosis by 5.8 ± 1.6 years. The age at onset of aortic stenosis was similar among patients with and without gout (78.7 ± 1.8 vs 75.8 ± 1.0 years old, P = .16). Aortic stenosis patients had a markedly higher prevalence of precedent gout than age-matched controls. Whether gout is a marker of, or a risk factor for, the development of aortic stenosis remains uncertain. Studies investigating the potential role of gout in the pathophysiology of aortic stenosis are warranted and could have therapeutic implications. Published by Elsevier Inc.

  8. Transcatheter aortic valve replacement for bicuspid aortic stenosis 13years post heart transplant.

    PubMed

    Julien, Maureen B; Desai, Nimesh; Brozena, Susan; Herrmann, Howard C

    2016-12-16

    Despite the widespread use of transcatheter aortic valve replacement (TAVR) for moderate and high-risk patients with severe aortic stenosis, it is utilized less frequently in patients with bicuspid aortic valves (BAV). Orthotopic heart transplant (OHT) donors tend to be younger and may have undiagnosed BAV. We present a case of successful TAVR in a patient with BAV thirteen years after OHT.

  9. 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.

  10. Aortic root dilatation in young men with normally functioning bicuspid aortic valves

    PubMed Central

    Nistri, S; Sorbo, M; Marin, M; Palisi, M; Scognamiglio, R; Thiene, G

    1999-01-01

    OBJECTIVE—To evaluate the dimensions of the aortic root in a selected population of young males with isolated normally functioning bicuspid aortic valve.
DESIGN AND SETTING—Echocardiographic and Doppler evaluation of conscripts with bicuspid aortic valve at the time of military pre-enrolment screening in two military hospitals.
SUBJECTS AND METHODS—66 consecutive young men with a normally functioning bicuspid aortic valve were studied to assess aortic size at four aortic levels: annulus, sinuses of Valsalva, supra-aortic ridge, and proximal ascending aorta; 70 consecutive normal young subjects, matched for age and body surface area, were used as controls.
RESULTS—In men with a bicuspid aortic valve, the diameter of the aortic root was significantly larger than in controls at the sinuses (3.16 (0.37) v 2.87 (0.31) cm, p < 0.001), at the supra-aortic ridge (2.64 (0.46) v 2.47 (0.28) cm, p = 0.01), and at the level of the proximal ascending aorta (3.12 (0.48) v 2.69 (0.28) cm, p < 0.001). The prevalence of aortic root dilatation was 7.5% at the annulus (5/66), 19.6% at the sinuses (13/66), 15% at the supra-aortic ridge (10/66), and 43.9% at the ascending aorta (29/66); 32 subjects (48%) had aortic root dimensions comparable with controls, while 34 (52%) had definitely abnormal aortic root dimensions.
CONCLUSIONS—Aortic root enlargement in people with a bicuspid aortic valve occurs independently of haemodynamic abnormalities, age, and body size. However, there appear to be different subgroups of young adults with bicuspid aortic valves, one of which is characterised by aortic dilatation, possibly caused by a congenital abnormality of the aortic wall.


Keywords: bicuspid aortic valve; aortic root dilatation PMID:10377302

  11. Aortic dilatation in children with systemic hypertension.

    PubMed

    Gupta-Malhotra, Monesha; Devereux, Richard B; Dave, Archana; Bell, Cynthia; Portman, Ronald; Milewicz, Diana

    2014-04-01

    The aim of the study was to determine the presence of aortic dilatation in hypertensive children, the prevalence of which is 4% to 10% in hypertensive adults. Prospectively enrolled multiethnic children, untreated for their hypertension, underwent an echocardiogram to exclude congenital heart disease and evaluate for end-organ damage and aortic size. The aorta was measured in the parasternal long-axis view at three levels: the sinus of Valsalva, supra-tubular junction, and the ascending aorta. Aortic dilatation was determined by z-score >2 at any one of the levels measured. Hypertension was defined as blood pressure above the 95th percentile based on the Fourth Working Group criteria confirmed by 24-hour ambulatory blood pressure monitoring. Among 142 consecutive hypertensive children (median age, 14 years; 45% females) aortic dilatation was detected in 2.8% (95% confidence interval, 1%-7%; median age, 16 years; 100% females). Children with aortic dilatation, when compared with those without, had significantly more aortic valve insufficiency (P = .005) and left ventricular hypertrophy (P = .018). Prevalence of aortic dilatation was 2.8% and was associated with significantly more aortic insufficiency and left ventricular hypertrophy in comparison to those without aortic dilatation.

  12. Aortic Dilatation in Children with Systemic Hypertension

    PubMed Central

    Gupta-Malhotra, Monesha; Devereux, Richard B.; Dave, Archana; Bell, Cynthia; Portman, Ronald; Milewicz, Diana

    2014-01-01

    Background The aim of the study was to determine presence of aortic dilatation in hypertensive children, the prevalence of which is 4–10% in hypertensive adults. Methods Prospectively enrolled multiethnic children untreated for their hypertension, underwent an echocardiogram to exclude congenital heart disease and evaluate for end-organ damage and aortic size. The aorta was measured in the parasternal long-axis view at 3 levels: the sinus of Valsalva, supra-tubular junction and the ascending aorta. Aortic dilatation was determined by z-score > 2 at any 1 of the levels measured. Hypertension was defined as blood pressure above the 95th percentile based on the Fourth Working Group criteria confirmed by 24-hour ambulatory blood pressure monitoring. Results Among 142 consecutive hypertensive children (median age 14 years, 45% females) aortic dilatation was detected in 2.8% (95% CI 1% to 7%, median age 16 years, 100% females). Children with aortic dilatation, when compared to those without, had significantly more aortic valve insufficiency (p = 0.005) and left ventricular hypertrophy (p = 0.018). Conclusions Prevalence of aortic dilatation was 2.8% and was associated with significantly more aortic insufficiency and left ventricular hypertrophy in comparison to those without aortic dilatation. PMID:24507486

  13. [Surgery of aortic dissection: for which patient?].

    PubMed

    Verhoye, Jean-Philippe; Abouliatim, Issam; Larralde, Antoine; Beneux, Xavier; Heautot, Jean-François

    2011-01-01

    In the acute stage (less than two weeks), surgery is indicated for Stanford type A aortic dissections. With respect to the initial work-up, surgery consists in replacing the ascending aorta, sometimes the aortic arch (with supra aortic vessels reimplantation), and aortic valve replacement (valve replacement, Bentall valved tube or valve sparing Tyron David technique). Ischemic visceral complications must be searched for and treated by endovascular techniques or surgery. Aneurismal evolution of chronic dissections must be treated surgically. Replacement can encompass the entire aorta. Copyright © 2010. Published by Elsevier Masson SAS.

  14. Aortic Aneurysm: Etiopathogenesis and Clinicopathologic Correlations

    PubMed Central

    2016-01-01

    Aortic aneurysm (AA) is one of the life-threatening aortic diseases, leading to aortic rupture of any cause including atherosclerotic and non-atherosclerotic diseases. AA is diagnosed in a variable proportion of patients with dilated aorta by imaging modality. The etiopathogenesis of AA remains unclear in many aortic diseases. Furthermore, although it may be difficult to explain all phenotypes of patients even if genetic mutation could be identified in some proteins such as smooth muscle cell α-actin (ACTA2), myosin heavy chain 11 (MYH11) or SMAD3, individualized consideration of these factors in each patient is essential on the basis of clinicopathological characteristics. PMID:27375798

  15. Bacillus licheniformis prosthetic aortic valve endocarditis.

    PubMed Central

    Santini, F; Borghetti, V; Amalfitano, G; Mazzucco, A

    1995-01-01

    A 73-year old man developed an acute prosthetic aortic valve dehiscence for which emergent operation was undertaken. The intraoperative evidence of an aortic annular disruption and of a subannular abscess led to the hypothesis that an endocarditis process was involved. The aortic valve was replaced with a stentless porcine bioprosthesis. Cultures taken intraoperatively from the aortic area had a pure growth of aerobic, spore-forming, gram-positive bacilli identified as Bacillus licheniformis. The patient responded to specific antibiotic therapy with no relapse at a 20-month follow-up. The potentiality of B. licheniformis as a pathogen should be reconsidered. PMID:8576381

  16. Hypoplasia of the aortic root 1

    PubMed Central

    Nicks, Rowan; Cartmill, T.; Bernstein, L.

    1970-01-01

    We report a technique for the enlargement of a hypoplastic aortic root by an operation whereby the hypoplastic aortic root has been so enlarged by the insertion of a Dacron fabric gusset that it will accommodate a size 9A or larger Starr-Edwards prosthesis. Our experience in five patients is described. No matter what type of valve is used for replacement of a diseased aortic valve, and no matter what improved designs of valvular prosthesis are ultimately developed, it will be necessary (in the particular group described) to enlarge the aortic ring to accommodate a size which will function correctly without causing left ventricular outflow obstruction. Images PMID:5452289

  17. Aortic Stenosis: Changing Disease Concepts

    PubMed Central

    Rashedi, Nina

    2015-01-01

    Aortic stenosis (AS) occurs in almost 10% of adults over age 80 years with a mortality about 50% at 2 years unless outflow obstruction is relieved by aortic valve replacement (AVR). Development of AS is associated with anatomic, clinical and genetic risk factors including a bicuspid valve in 50%; clinical factors that include older age, hypertension, smoking, diabetes and elevated serum lipoprotein(a) [Lp(a)] levels; and genetic factors such as a polymorphism in the Lp(a) locus. Early stages of AS are characterized by focal areas of leaflet thickening and calcification. The rate of hemodynamic progression is variable but eventual severe AS is inevitable once even mild valve obstruction is present. There is no specific medical therapy to prevent leaflet calcification. Basic principles of medical therapy for asymptomatic AS are patient education, periodic echocardiographic and clinical monitoring, standard cardiac risk factor evaluation and modification and treatment of hypertension or other comorbid conditions. When severe AS is present, a careful evaluation for symptoms is needed, often with an exercise test to document symptom status and cardiac reserve. In symptomatic patients with severe AS, AVR improves survival and relieves symptoms. In asymptomatic patients with severe AS, AVR also is appropriate if ejection fraction is < 50%, disease progression is rapid or AS is very severe (aortic velocity > 5 m/s). The choice of surgical or transcatheter AVR depends on the estimated surgical risk plus other factors such as frailty, other organ system disease and procedural specific impediments. PMID:26140146

  18. Cocking of a poppet-disc prosthesis in the aortic position. A cause of intermittent aortic regurgitation.

    PubMed

    Hammer, W J; Hearne, M J; Roberts, W C

    1976-02-01

    Intermittent aortic regurgitation due to cocking is described for the first time after replacement of the aortic valve with a poppet-disc prosthesis. A combination of disc grooving and strut thrombus produced the cocking with resultant aortic regurgitation.

  19. Effect of timing of umbilical cord clamping of term infants on maternal and neonatal outcomes.

    PubMed

    McDonald, Susan J; Middleton, Philippa

    2008-04-16

    Policies for timing of cord clamping vary, with early cord clamping generally carried out in the first 60 seconds after birth, whereas later cord clamping usually involves clamping the umbilical cord greater than one minute after the birth or when cord pulsation has ceased. To determine the effects of different policies of timing of cord clamping at delivery of the placenta on maternal and neonatal outcomes. We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (December 2007). Randomised controlled trials comparing early and late cord clamping. Two review authors independently assessed trial eligibility and quality and extracted data. We included 11 trials of 2989 mothers and their babies. No significant differences between early and late cord clamping were seen for postpartum haemorrhage or severe postpartum haemorrhage in any of the five trials (2236 women) which measured this outcome (relative risk (RR) for postpartum haemorrhage 500 mls or more 1.22, 95% confidence interval (CI) 0.96 to 1.55). For neonatal outcomes, our review showed both benefits and harms for late cord clamping. Following birth, there was a significant increase in infants needing phototherapy for jaundice (RR 0.59, 95% CI 0.38 to 0.92; five trials of 1762 infants) in the late compared with early clamping group. This was accompanied by significant increases in newborn haemoglobin levels in the late cord clamping group compared with early cord clamping (weighted mean difference 2.17 g/dL; 95% CI 0.28 to 4.06; three trials of 671 infants), although this effect did not persist past six months. Infant ferritin levels remained higher in the late clamping group than the early clamping group at six months. One definition of active management includes directions to administer an uterotonic with birth of the anterior shoulder of the baby and to clamp the umbilical cord within 30-60 seconds of birth of the baby (which is not always feasible in practice). In this review delaying

  20. The concept of aortic replacement based on computational fluid dynamic analysis: patient-directed aortic replacement†

    PubMed Central

    Heim, Laurant; Poole, Robert J.; Warwick, Richard; Poullis, Michael

    2013-01-01

    OBJECTIVES Aortic replacement is based on the aortic diameter in the absence of dissection or connective tissue diseases. Frequently, a number of different aortic-to-prosthetic anastomotic positions are possible depending on patient factors and surgeon preferences. High stress on residual aortic tissue may result in aneurysm formation or aneurysmal dilatation. Utilizing a computational fluid dynamic evaluation, we aimed to define possible optimal operative interventions with regard to the extent of aortic replacement. METHODS For proof of principle, a computational fluid dynamic (CFD) analysis, using Fluent 6.2 (Ansys UK Ltd, Sheffield, UK), was performed on a simplified ascending arch and descending aortic geometry. Wall shear stress in three dimensions was assessed for the standard operations: ascending aortic replacement, arch replacement and proximal descending aortic replacement. RESULTS Hermiarch replacement is superior to isolated ascending aortic replacement with regard to residual stress analysis on tissues (up to a 10-fold reduction). Aortic arch replacement with island implantation of the supra-aortic vessels may potentially result in high stress on the residual aorta (10-fold increase). Aortic arch replacement with individual supra-aortic vessel implantation may result in areas of high stress (10-fold increase) on native vessels if an inadequate length of supra-aortic tissue is not resected, regardless of it being aneurysmal. CONCLUSIONS Computational fluid dynamic evaluation, which will have to be patient-specific, 3D anatomical and physiological, potentially has enormous implications for operative strategy in aortic replacement surgery. CFD analysis may direct the replacement of normal-diameter aortas in the future. PMID:23407695