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Sample records for flow modifying endovascular

  1. Endovascular blood flow measurement system

    NASA Astrophysics Data System (ADS)

    Khe, A. K.; Cherevko, A. A.; Chupakhin, A. P.; Krivoshapkin, A. L.; Orlov, K. Yu

    2016-06-01

    In this paper an endovascular measurement system used for intraoperative cerebral blood flow monitoring is described. The system is based on a Volcano ComboMap Pressure and Flow System extended with analogue-to-digital converter and PC laptop. A series of measurements performed in patients with cerebrovascular pathologies allows us to introduce “velocity-pressure” and “flow rate-energy flow rate” diagrams as important characteristics of the blood flow. The measurement system presented here can be used as an additional instrument in neurosurgery for assessment and monitoring of the operation procedure. Clinical data obtained with the system are used for construction of mathematical models and patient-specific simulations. The monitoring of the blood flow parameters during endovascular interventions was approved by the Ethics Committee at the Meshalkin Novosibirsk Research Institute of Circulation Pathology and included in certain surgical protocols for pre-, intra- and postoperative examinations.

  2. Investigation of new flow modifying endovascular image-guided interventional (EIGI) techniques in patient-specific aneurysm phantoms (PSAPs) using optical imaging.

    PubMed

    Sherman, Jr; Rangwala, Hs; Ionita, Cn; Dohatcu, Ac; Lee, Jw; Bednarek, Dr; Hoffmann, Kr; Rudin, S

    2008-01-01

    Effective minimally invasive treatment of cerebral bifurcation aneurysms is challenging due to the complex and remote vessel morphology. An evaluation of endovascular treatment in a phantom involving image-guided deployment of new asymmetric stents consisting of polyurethane patches placed to modify blood flow into the aneurysm is reported. The 3D lumen-geometry of a patient-specific basilar-artery bifurcation aneurysm was derived from a segmented computed-tomography dataset. This was used in a stereolithographic rapid-prototyping process to generate a mold which was then used to create any number of exact wax models. These models in turn were used in a lost-wax technique to create transparent elastomer patient-specific aneurysm phantoms (PSAP) for evaluating the effectiveness of asymmetric-stent deployment for flow modification. Flow was studied by recording real-time digitized video images of optical dye in the PSAP and its feeding vessel. For two asymmetric stent placements: through the basilar into the right-posterior communicating artery (RPCA) and through the basilar into the left-posterior communicating artery (LPCA), the greatest deviation of flow streamlines away from the aneurysm occurred for the RPCA stent deployment. Flow was also substantially affected by variations of inflow angle into the basilar artery, resulting in alternations in washout times as derived from time-density curves. Evaluation of flow in the PSAPs with real-time optical imaging can be used to determine new EIGI effectiveness and to validate computational-fluid-dynamic calculations for EIGI-treatment planning.

  3. In Vitro Validation of Endovascular Doppler-derived Flow Rates in Models of the Cerebral Circulation

    PubMed Central

    McGah, P M; Nerva, J D; Morton, R P; Barbour, M C; Levitt, M R; Mourad, P D; Kim, L J; Aliseda, A

    2015-01-01

    This study presents validation of endovascular Doppler velocimetry-based volumetric flow rate measurements conducted in a pulsatile flow loop simulating conditions in both the internal carotid and basilar artery. In vitro models of cerebral vessels, each containing an aneurysm, were fabricated from patient anatomies extracted from 3D rotational angiography. Flow velocity measurements were collected with three different experimental techniques: an endovascular Doppler wire, Particle Image Velocimetry, and a time-resolved ultrasonic flow meter. Womersley’s theory of pulsatile flow in a cylindrical vessel was used to compute time-resolved volumetric flow rates from the endovascular Doppler velocity. The volumetric flow rates computed from the Doppler measurements were compared to those from the Particle Image Velocimetry profile measurements, and the direct measurements from the ultrasonic flow meter. The study establishes confidence intervals for any systematic or random errors associated with the wire-derived flow rates as benchmarked to the other two modalities. There is an approximately 10% random error in the Doppler-derived peak and time-averaged flow rates. There is a measurable uniform bias, about 15% too low, in the time-averaged Doppler-derived flow rates. There is also a small proportional bias in the peak systolic Doppler-derived flow rates. Potential sources of error are also discussed. PMID:26450643

  4. Invasive radiologic management of hemodialysis fistulas: measuring flow with an endovascular catheter.

    PubMed

    García-Medina, J

    2015-01-01

    To analyze the values of flow obtained with an endovascular catheter, and to determine whether they are more reliable than angiographic and clinical findings for planning and for determining the outcome of invasive radiologic treatment of hemodialysis fistulas, as well as to determine the safety of this technique during interventional radiology procedures. We used endovascular catheters to measure flow in 341 vascular accesses for hemodialysis (162 [47.6%] distal fistulas, 132 [38.4%] humeral fistulas, and 47 [14%] arteriovenous grafts) in 598 procedures (a total of 3,051 flow measurements). Dysfunction was most commonly due to high pressures and flow deficits. The catheter was used to measure the results of radiologic treatment in 419 (70%) cases and only to measure the control of flow in the hemodialysis access in 179 (30%) cases. In the cases where lesions of the access had been treated radiologically, the flow improved by a mean of 1,232ml/min. In 2 (0.35%) cases, the tip of the catheter perforated the wall of the vein; this complication was resolved by inflating a low pressure balloon. Endovascular catheters are useful for measuring flow in invasive vascular radiology procedures for hemodialysis. In assessing the hemodynamic status of a vascular access, they are most helpful in determining whether stenosis is present. Copyright © 2013 SERAM. Published by Elsevier España, S.L.U. All rights reserved.

  5. Effect of collateral blood flow on patients undergoing endovascular therapy for acute ischemic stroke.

    PubMed

    Marks, Michael P; Lansberg, Maarten G; Mlynash, Michael; Olivot, Jean-Marc; Straka, Matus; Kemp, Stephanie; McTaggart, Ryan; Inoue, Manabu; Zaharchuk, Greg; Bammer, Roland; Albers, Gregory W

    2014-04-01

    Our aim was to determine the relationships between angiographic collaterals and diffusion/perfusion findings, subsequent infarct growth, and clinical outcome in patients undergoing endovascular therapy for ischemic stroke. Sixty patients with a thrombolysis in cerebral infarction (TICI) score of 0 or 1 and internal carotid artery/M1 occlusion at baseline were evaluated. A blinded reader assigned a collateral score using a previous 5-point scale, from 0 (no collateral flow) to 4 (complete/rapid collaterals to the entire ischemic territory). The analysis was dichotomized to poor flow (0-2) versus good flow (3-4). Collateral score was correlated with baseline National Institutes of Health Stroke Scale, diffusion-weighted imaging volume, perfusion-weighted imaging volume (Tmax ≥6 seconds), TICI reperfusion, infarct growth, and modified Rankin Scale score at day 90. Collateral score correlated with baseline National Institutes of Health Stroke Scale (P=0.002) and median volume of tissue at Tmax ≥6 seconds (P=0.009). Twenty-nine percent of patients with poor collateral flow had TICI 2B-3 reperfusion versus 65.5% with good flow (P=0.009). Patients with poor collaterals who reperfused (TICI 2B-3) were more likely to have a good functional outcome (modified Rankin Scale score 0-2 at 90 days) compared with patients who did not reperfuse (odds ratio, 12; 95% confidence interval, 1.6-98). There was no difference in the rate of good functional outcome after reperfusion in patients with poor collaterals versus good collaterals (P=1.0). Patients with poor reperfusion (TICI 0-2a) showed a trend toward greater infarct growth if they had poor collaterals versus good collaterals (P=0.06). Collaterals correlate with baseline National Institutes of Health Stroke Scale, perfusion-weighted imaging volume, and good reperfusion. However, target mismatch patients who reperfuse seem to have favorable outcomes at a similar rate, irrespective of the collateral score. http

  6. Vertebral artery pseudoaneurysms secondary to blunt trauma: Endovascular management by means of neurostents and flow diverters.

    PubMed

    Cohen, José E; Gomori, John M; Rajz, Gustavo; Rosenthal, Guy; El Hassan, Hosni Abu; Moscovici, Samuel; Itshayek, Eyal

    2016-10-01

    Extracranial vertebral pseudoaneurysms that develop following blunt trauma to the cervical area may have a benign course; however, embolic or ischemic stroke and progressive pseudoaneurysm enlargement may occur. We review the presentation and endovascular management of pseudoaneurysms of the cervical vertebral artery (VA) due to blunt trauma in nine patients (eight male, mean age 27years). Pseudoaneurysms occurred in dominant vessels in seven patients and coexisted with segmental narrowing in six. We favored endovascular intervention during the acute phase only in cases with significant narrowing of a dominant VA, especially when anticoagulation was contraindicated. Four patients were treated during the acute stage (contraindication to anticoagulation, mass effect, severely injured dominant VA/impending stroke); five during the chronic phase (pseudoaneurysm growth, ischemic stroke on aspirin prophylaxis, patient preference). Reconstructive techniques were favored over deliberate endovascular occlusion when dominant vessels were involved. Arterial reconstruction was performed in eight of nine patients using a flow-diverter implant (5 patients), stent-assisted coiling (1), overlapping stent implant (1), or implantation of a balloon-expandable stent (1). Deliberate VA occlusion with coils was performed in one of nine patients due to suboptimal expansion of the stented artery after flow-diverter implant. No neurological complications occurred during follow-up. All cases treated by reconstructive techniques showed complete, persistent pseudoaneurysm occlusion and full arterial patency. Endovascular therapy of traumatic VA pseudoaneurysms using neurostents and flow-diverters resulted in occlusion of the pseudoaneurysms, preservation of the parent vessel, and no periprocedural or delayed clinical complications, supporting the feasibility and safety of the approach. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Collateral flow averts hemorrhagic transformation after endovascular therapy for acute ischemic stroke.

    PubMed

    Bang, Oh Young; Saver, Jeffrey L; Kim, Suk Jae; Kim, Gyeong-Moon; Chung, Chin-Sang; Ovbiagele, Bruce; Lee, Kwang Ho; Liebeskind, David S

    2011-08-01

    Collaterals sustain the ischemic penumbra to limit growth of the infarct core before revascularization, yet the impact of baseline collateral flow on hemorrhagic transformation (HT) after endovascular therapy remains unknown. A collaborative study from 2 stroke centers in distinct geographic regions included 222 consecutive patients who received endovascular therapy for acute cerebral ischemia. The influence of collaterals on HT was analyzed in distinct case scenarios relative to baseline collateral grade at angiography (0 to 1 versus 2 to 4) and recanalization (Thrombolysis in Myocardial Ischemia scale, 0 to 1 versus 2 to 3): good collaterals and successful recanalization (n=98), poor collaterals with successful recanalization (n=43), good collaterals and no recanalization(n=46), and poor collaterals and no recanalization (n=35). HT after endovascular therapy occurred in 103 (46.4%) patients; 42 (18.9%) were symptomatic. HT was more frequently observed in patients with poor collaterals and recanalization than in other groups (P=0.048). When revascularization was achieved, patients with poorer collaterals were more likely to have symptomatic worsening with HT (r=-0.181, P=0.032). Multiple logistic regression analysis identified aggressive treatment (OR, 2.558 for Merci clot retrieval; 95% CI, 1.153 to 5.678; OR, 3.618 for combined fibrinolytics and mechanical therapy; 95% CI, 1.551 to 8.437; and OR, 2.085 for intravenous thrombolysis before endovascular therapy; 95% CI, 1.096 to 3.969), poor collaterals and recanalization (OR, 2.666; 95% CI, 1.163 to 6.113), and serum glucose levels (OR, 1.007; 95% CI, 1.000 to 1.014) as independent predictors of HT. Angiographic grade of collateral flow strongly influences the rate of HT after therapeutic recanalization for acute ischemic stroke. Collateral status readily available from baseline angiography may therefore refine therapeutic decision-making in acute cerebral ischemia.

  8. Numerical investigation of pulsatile flow in endovascular stents

    NASA Astrophysics Data System (ADS)

    Rouhi, A.; Piomelli, U.; Vlachos, P.

    2013-09-01

    The flow in a plane channel with two idealized stents (one Λ-shaped, the other X-shaped) is studied numerically. A periodic pressure gradient corresponding to one measured in the left anterior descending coronary artery was used to drive the flow. Two Reynolds numbers were examined, one (Re = 80) corresponding to resting conditions, the other (Re = 200) to exercise. The stents were implemented by an immersed boundary method. The formation and migration of vortices that had been observed experimentally was also seen here. In the previous studies, the compliance mismatch between stent and vessel was conjectured to be the reason for this phenomenon. However, in the present study we demonstrate that the vortices form despite the fact that the walls were rigid. Flow visualization and quantitative analysis lead us to conclude that this process is due to the stent wires that generate small localized recirculation regions that, when they interact with the near-wall flow reversal, result in the formation of these vortical structures. The recirculation regions grow and merge when the imposed waveform produces near-wall flow reversal, forming coherent quasi-spanwise vortices, that migrate away from the wall. The flow behavior due to the stents was compared with an unstented channel. The geometric characteristics of the Λ-stent caused less deviation of the flow from an unstented channel than the X-stent. Investigating the role of advection and diffusion indicated that at Re = 80 advection has negligible contribution in the transport mechanism. Advection plays a role in the generation of streamwise vortices created for both stents at both Reynolds numbers. The effect of these vortices on the near-wall flow behavior is more significant for the Λ-stent compared to the X-stent and at Re = 200 with respect to Re = 80. Finally, it was observed that increasing the Reynolds number leads to early vortex formation and the creation of the vortex in a stented channel is coincident with

  9. A modified technique for Gore Excluder limb deployment in difficult iliac anatomy during endovascular abdominal aortic aneurysm repair.

    PubMed

    Vourliotakis, George; Katsargyris, Αthanasios; Tielliu, Ignace F J; Zeebregts, Clark J; Verhoeven, Eric L G

    2015-02-01

    Complex iliac anatomy including extreme tortuosity constitutes a relative contraindication for endovascular abdominal aortic aneurysm repair with additional risk of limb-graft occlusion. The Gore Excluder limb-graft is a flexible stent-graft, which adapts easily to iliac tortuosity. Nevertheless, the presence of the stiff guide wire does not always allow for an ideal apposition of the stent graft to the angulated common iliac artery vessel wall. We describe herein a modified technique for Gore Excluder limb-graft deployment with partial removal of the stiff wire in cases with difficult tortuous or narrow iliac arteries during endovascular abdominal aortic aneurysm repair. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

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

    PubMed

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

    2016-12-14

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

  11. Predictors for Better Blood-Flow Restoration of Long-Segmental Below-the-Knee Chronic Total Occlusions after Endovascular Therapy in Diabetic Patients

    PubMed Central

    Song, Xiao-Li; Zhu, Yue-Qi; Lu, Hai-Tao; Liu, Fang; Wei, Li-Ming; Kang, Heoung Keun

    2016-01-01

    Objective To prospectively investigate predictors for good restoration of blood flow of below-the-knee (BTK) chronic total occlusions (CTOs) after endovascular therapy in diabetes mellitus (DM) patients. Materials and Methods A total of 120 long-segmental (≥ 5 cm) BTK, CTOs in 81 patients who underwent recanalization were included in this study. After angioplasty, blood-flow restoration was assessed using modified thrombolysis in myocardial ischemia grades and classified as good flow (grade 3) and poor flow (grade 1/2). One hundred and six CTOs with successful recanalization were divided into a good flow group (GFG; n = 68) and poor flow group (PFG; n = 38). Multivariate logistic regression analyses were undertaken to determine independent predictors of blood-flow restoration. Receiver operating characteristic curves were constructed to determine the best cutoff value. The prevalence of target-lesion restenosis during follow-up was compared between two groups. Results Univariate analyses suggested that CTOs in GFG were characterized by lighter limb ischemia (p = 0.03), shorter course of ischemic symptoms (p < 0.01) and lesion length (p = 0.04), more frequent use of intraluminal angioplasty (p = 0.03), and higher runoff score (p < 0.01) than those in PFG. Multivariate regression analyses suggested that distal runoffs (p = 0.001; odds ratio [OR], 10.32; 95% confidence interval [CI]: 4.082–26.071) and lesion length (p < 0.001; OR, 1.26; 95% CI: 1.091–1.449) were independent predictors for good flow restoration. Kaplan-Meier analyses at 12 months showed a higher prevalence of non-restenosis in GFG (p < 0.01). Conclusion Distal runoffs and lesion length are independent predictors for good flow restoration for long-segmental BTK, CTOs in DM patients who receive endovascular therapy. PMID:27833403

  12. Alterations of blood flow pattern after triple stent endovascular treatment of saccular abdominal aortic aneurysm: a porcine model.

    PubMed

    Oliveira, Jahir Richard DE; Aquino, Maurício DE Amorim; Barros, Svetlana; Pitta, Guilherme Benjamin Brandão; Pereira, Adamastor Humberto

    2016-01-01

    to determine the blood flow pattern changes after endovascular treatment of saccular abdominal aortic aneurysm with triple stent. we conducted a hemodynamic study of seven Landrace and Large White pigs with saccular aneurysms of the infrarenal abdominal aorta artificially produced according to the technique described. The animals were subjected to triple stenting for endovascular aneurysm. We evaluated the pattern of blood flow by duplex scan before and after stent implantation. We used the non-paired Mann-Whitney test for statistical analysis. there was a significant decrease in the average systolic velocity, from 127.4cm/s in the pre-stent period to 69.81cm/s in the post-stent phase. There was also change in the flow pattern from turbulent in the aneurysmal sac to laminate intra-stent. there were changes in the blood flow pattern of saccular abdominal aortic aneurysm after endovascular treatment with triple stent. determinar as alterações do padrão do fluxo sanguíneo após tratamento endovascular do aneurisma sacular de aorta abdominal com triplo stent. estudo hemodinâmico de sete suínos das raças Landrace e Large White portadores de aneurismas saculares de aorta abdominal infrarrenal artificialmente produzidos segundo técnica descrita. Os animais foram submetidos a implante de triplo stent para correção endovascular do aneurisma e reavaliados por duplex scan quanto ao padrão do fluxo sanguíneo antes e após o implante dos stents. A análise estatística foi realizada com o teste Mann-Whitney não pareado. verificou-se uma queda significativa da velocidade sistólica média de 127,4cm/s na fase pré-stent para 69,81cm/s na fase pós-stent. Houve ainda mudança no padrão do fluxo de turbilhonar no saco aneurismático para laminar intrastent. o estudo demonstrou alterações do padrão do fluxo sanguíneo do aneurisma sacular de aorta abdominal após tratamento endovascular com triplo stent.

  13. Endovascular therapy using flow diversion for giant internal carotid artery pseudoaneurysm arising in the setting of an invasive pituitary macroadenoma

    PubMed Central

    Syed, Almas; Marashi, Keyan B.; O'Rourke, Brian D.; Hise, Joseph H.; Opatowsky, Michael J.; Layton, Kennith F.

    2017-01-01

    This report illustrates the unusual occurrence of a pseudoaneurysm arising in the setting of a skull base mass and describes the first reported use of endovascular flow diversion therapy in such a setting. A 63-year-old man with occasional headaches during the preceding month presented with the acute onset of severe left retroorbital headache and oculomotor nerve palsy. Computed tomography (CT) and CT angiogram revealed a destructive skull base mass with an associated giant probable pseudoaneurysm of the cavernous segment of the left internal carotid artery. The patient underwent endoscopic transsphenoidal biopsy with a subsequent diagnosis of prolactinoma. Endovascular therapy utilizing two Pipeline™ flow diversion embolization devices was performed with subsequent resolution of the patient's headache and improvement in his cranial nerve deficits/cavernous sinus syndrome. PMID:28127130

  14. Endovascular treatment of intracranial aneurysms in the flow diverter era: frequency of use and results in a consecutive series of 550 treatments in a single centre.

    PubMed

    van Rooij, Willem Jan; Bechan, Ratna S; Peluso, Jo P; Sluzewski, Menno

    2014-01-01

    Flow diverter devices became available in our department in 2009. We considered treatment with flow diverters only in patients with aneurysms not suitable for surgery or conventional endovascular techniques. This paper presents our preliminary experience with flow diverters in a consecutive series of 550 endovascular aneurysm treatments. Between January 2009 and July 2013, 550 endovascular treatments for intracranial aneurysms were performed. Of these, 490 were first-time aneurysm treatments in 464 patients and 61 were additional treatments of previously coiled aneurysms in 51 patients. Endovascular treatments consisted of selective coiling in 445 (80.8%), stent-assisted coiling in 68 (12.4%), balloon-assisted coiling in 13 (2.4%), parent vessel occlusion in 12 (2.2%) and flow diverter treatment in 12 (2.2%). Eleven patients with 12 aneurysms were treated with flow diverters. Two patients had ruptured dissecting aneurysms. One patient with a basilar trunk aneurysm died of acute in stent thrombosis and another patient died of brain stem ischaemia at 32 months follow-up. One patient had ischaemia with permanent neurological deficit. Two aneurysms are still open at up to 30 months follow-up. Flow diversion was used in 2% of all endovascular treatments. Both our own poor results and the high complication rates reported in the literature have converted our initial enthusiasm to apprehension and hesitancy. The safety and efficacy profile of flow diversion should discourage the use of these devices in aneurysms that can be treated with other techniques.

  15. Flow Diverters as Useful Adjunct to Traditional Endovascular Techniques in Treatment of Direct Carotid-Cavernous Fistulas.

    PubMed

    Ogilvy, Christopher S; Motiei-Langroudi, Rouzbeh; Ghorbani, Mohammad; Griessenauer, Christoph J; Alturki, Abdulrahman Y; Thomas, Ajith J

    2017-09-01

    Direct carotid-cavernous sinus fistulas (CCFs) are high-flow arteriovenous shunts that are typically the result of a severe head injury. The endovascular treatment of these lesions includes the use of detachable balloons, coils, liquid embolic agents, and covered stents. To minimize the chance of treatment failure and subsequent complications, endoluminal reconstruction using a flow-diverting stent may be added to the treatment construct. We present 3 cases and review the existing literature. Three patients with direct traumatic CCFs were treated with either coils, coils and Onyx, or a detachable balloon, followed by placement of a flow-diverting stent for endoluminal reconstruction. All 3 cases had complete angiographic occlusion of the CCFs and recovered clinically. No complications were observed. We believe that endovascular coil or balloon occlusion of the fistula from either a transvenous or transarterial approach followed by flow diversion may be an appropriate treatment for direct CCFs. This addition of a flow diverter may facilitate endothelialization of the injury to the internal carotid artery. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Staged endovascular and surgical treatment of slow-flow vulvar venous malformations.

    PubMed

    Nassiri, Naiem; O, Teresa M J; Rosen, Robert J; Moritz, Jacques; Waner, Milton

    2013-05-01

    The objective of the study was to report our experience in a rare series of treated symptomatic slow-flow vulvar venous malformations (VVMs) using a staged, multidisciplinary approach. Consecutive patients with symptomatic lesions treated over a 7 year period (2005-2012) were followed up for technical success, resolution of symptoms, aesthetic outcomes, and complications. Direct endovenous sclerotherapy (DEVS) using sodium tetradecyl sulfate (STS) foam was performed in all patients under ultrasound and contrast-enhanced fluoroscopic guidance. Surgical excision and layered primary closure was performed within 24 hours after the last DEVS session. Eleven patients (mean age, 25 years; range, 4-43 years) were treated. Presenting symptoms included pain (n = 11), soft tissue swelling (n = 11), local heaviness (n = 11), dyspareunia (n = 2), and dysmenorrhea (n = 2). Most were isolated lesions (n = 8). There were 2 cases of Klippel-Trénaunay syndrome and 1 case of Maffucci syndrome. The latter required Nd:YAG laser photocoagulation prior to sclerotherapy. On average, approximately 3 DEVS sessions were required prior to surgical excision (range, 1-6). Mean estimated surgical blood loss was 130 mL (range, 20-400 mL). Mean follow-up was 23 months (range, 3-55 months). Elimination of pain and soft tissue redundancy was achieved in all patients with satisfactory aesthetic outcomes. All patients experienced minor pain and swelling after DEVS. Following surgical excision, there was 1 case of hematoma and wound dehiscence requiring surgical evacuation. No other reinterventions, endovascular or surgical, were required. VVMs require increased awareness and appropriate preoperative evaluation for proper identification and treatment. A multidisciplinary approach can provide improvement in clinical signs and symptoms with satisfactory cosmesis and minimal complications. Copyright © 2013 Mosby, Inc. All rights reserved.

  17. The use of telescoped flow diverters as an endovascular bypass in the management of symptomatic chronic carotid occlusion.

    PubMed

    Cohen, José E; Gomori, John M; Ben-Hur, Tamir; Moscovici, Samuel; Itshayek, Eyal

    2012-07-01

    Flow diverters constitute a new generation of flexible self-expanding, stent-like devices with a high-metal surface-area coverage for the endovascular management of wide-necked, fusiform, large, and giant unruptured intracranial aneurysms. They achieve aneurysm occlusion through endoluminal reconstruction of the dysplastic segment of the parent artery that gives rise to the aneurysm. To our knowledge, there is no report on the use of flow diverters for the management of occlusive cerebrovascular disease. We describe the novel use of telescoped flow diverters in a construct that acts as an endovascular bypass for the management of symptomatic chronic carotid occlusion. In long carotid occlusions with a burden of extensive clots and atherosclerotic plaque, we found that the reduced porosity of the diverter mesh serves as an effective barrier to in-stent clot protrusion and distal embolization. Diverter implantation allows subsequent angioplasty. With this patient report, we propose a new potential application for flow diverters in the management of occlusive cerebrovascular disease. The optimal application of these devices will continue to be defined as clinical experience evolves. Copyright © 2011 Elsevier Ltd. All rights reserved.

  18. Finite Element Modeling of Endovascular Intervention Enables Hemodynamic Prediction of Complex Treatment Strategies for Coiling and Flow Diversion

    PubMed Central

    Damiano, Robert J.; Ma, Ding; Xiang, Jianping; Siddiqui, Adnan H.; Snyder, Kenneth V.; Meng, Hui

    2016-01-01

    Endovascular interventions using coil embolization and flow diversion are becoming the mainstream treatment for intracranial aneurysms (IAs). To help assess the effect of intervention strategies on aneurysm hemodynamics and treatment outcome, we have developed a finite-element-method (FEM)-based technique for coil deployment along with our HiFiVS technique for flow diverter (FD) deployment in patient-specific IAs. We tested four clinical intervention strategies: coiling (1–8 coils), single FD, FD with adjunctive coils (1–8 coils), and overlapping FDs. By evaluating post-treatment hemodynamics using computational fluid dynamics (CFD), we compared the flow-modification performance of these strategies. Results show that a single FD provides more reduction in inflow rate than low PD coiling, but less reduction in average velocity inside the aneurysm. Adjunctive coils add no additional reduction of inflow rate beyond a single FD until coil PD exceeds 11%. This suggests that the main role of FDs is to divert inflow, while that of coils is to create stasis in the aneurysm. Overlapping FDs decreases inflow rate, average velocity, and average wall shear stress (WSS) in the aneurysm sac, but adding a third FD produces minimal additional reduction. In conclusion, our FEM-based techniques for virtual coiling and flow diversion enable recapitulation of complex endovascular intervention strategies and detailed hemodynamics to identify hemodynamic factors that affect treatment outcome. PMID:26169778

  19. Finite element modeling of endovascular coiling and flow diversion enables hemodynamic prediction of complex treatment strategies for intracranial aneurysm.

    PubMed

    Damiano, Robert J; Ma, Ding; Xiang, Jianping; Siddiqui, Adnan H; Snyder, Kenneth V; Meng, Hui

    2015-09-18

    Endovascular interventions using coil embolization and flow diversion are becoming the mainstream treatment for intracranial aneurysms (IAs). To help assess the effect of intervention strategies on aneurysm hemodynamics and treatment outcome, we have developed a finite-element-method (FEM)-based technique for coil deployment along with our HiFiVS technique for flow diverter (FD) deployment in patient-specific IAs. We tested four clinical intervention strategies: coiling (1-8 coils), single FD, FD with adjunctive coils (1-8 coils), and overlapping FDs. By evaluating post-treatment hemodynamics using computational fluid dynamics (CFD), we compared the flow-modification performance of these strategies. Results show that a single FD provides more reduction in inflow rate than low packing density (PD) coiling, but less reduction in average velocity inside the aneurysm. Adjunctive coils add no additional reduction of inflow rate beyond a single FD until coil PD exceeds 11%. This suggests that the main role of FDs is to divert inflow, while that of coils is to create stasis in the aneurysm. Overlapping FDs decreases inflow rate, average velocity, and average wall shear stress (WSS) in the aneurysm sac, but adding a third FD produces minimal additional reduction. In conclusion, our FEM-based techniques for virtual coiling and flow diversion enable recapitulation of complex endovascular intervention strategies and detailed hemodynamics to identify hemodynamic factors that affect treatment outcome.

  20. Impact of Endovascular Technique on Fluoroscopy Usage: Stent-Assisted Coiling versus Flow Diversion for Paraclinoid Internal Carotid Artery Aneurysms

    PubMed Central

    Miller, Timothy R; Jindal, Gaurav; Krejza, Jaroslaw; Gandhi, Dheeraj

    2014-01-01

    Summary Flow diversion is increasingly being utilized for the treatment of internal carotid artery (ICA) aneurysms. The purpose of this study was to evaluate the impact of endovascular technique--flow diversion versus stent-assisted coiling (SAC) on fluoroscopy time in patients treated for wide-neck paraclinoid ICA aneurysms. A retrospective review identified the 20 most recent consecutive patients treated for wide-neck paraclinoid ICA aneurysms by flow diversion and SAC respectively. Fluoroscopy time, cumulative dose area-product (DAP), contrast usage, intra-procedural complications, and total procedure time were collected and compared between the two treatment techniques. Treatment groups were comparable in terms of demographics, contrast usage, and clinical and angiographic outcomes. Flow diversion was associated with a significant reduction in fluoroscopy time (52.0 minutes versus 77.4 minutes), and demonstrated a strong trend towards shorter total procedure time (172 minutes versus 202 minutes). Average patient radiation exposure as measured by DAP was lower in the flow diversion group, 13225 mGyxcm2 versus 15124 mGyxcm2, although this finding was not statistically significant. There was no significant difference in contrast usage between the two groups, 152 ml and 159 (flow diversion and SAC respectively). The rate of complete aneurysm occlusion was higher in the flow diversion group (80% versus 60%). Endovascular treatment of paraclinoid ICA aneurysms with flow diversion is associated with shorter fluoroscopy times compared to stent-assisted coiling. There is also a likely reduction in overall procedure time. These results should be considered when recommending a treatment course for patients with such lesions. PMID:25489897

  1. Impact of Endovascular Technique on Fluoroscopy Usage: Stent-Assisted Coiling versus Flow Diversion for Paraclinoid Internal Carotid Artery Aneurysms.

    PubMed

    Miller, Timothy R; Jindal, Gaurav; Krejza, Jaroslaw; Gandhi, Dheeraj

    2014-12-01

    Flow diversion is increasingly being utilized for the treatment of internal carotid artery (ICA) aneurysms. The purpose of this study was to evaluate the impact of endovascular technique--flow diversion versus stent-assisted coiling (SAC) on fluoroscopy time in patients treated for wide-neck paraclinoid ICA aneurysms. A retrospective review identified the 20 most recent consecutive patients treated for wide-neck paraclinoid ICA aneurysms by flow diversion and SAC respectively. Fluoroscopy time, cumulative dose area-product (DAP), contrast usage, intra-procedural complications, and total procedure time were collected and compared between the two treatment techniques. Treatment groups were comparable in terms of demographics, contrast usage, and clinical and angiographic outcomes. Flow diversion was associated with a significant reduction in fluoroscopy time (52.0 minutes versus 77.4 minutes), and demonstrated a strong trend towards shorter total procedure time (172 minutes versus 202 minutes). Average patient radiation exposure as measured by DAP was lower in the flow diversion group, 13225 mGy(x)cm(2) versus 15124 mGy(x)cm(2), although this finding was not statistically significant. There was no significant difference in contrast usage between the two groups, 152 ml and 159 (flow diversion and SAC respectively). The rate of complete aneurysm occlusion was higher in the flow diversion group (80% versus 60%). Endovascular treatment of paraclinoid ICA aneurysms with flow diversion is associated with shorter fluoroscopy times compared to stent-assisted coiling. There is also a likely reduction in overall procedure time. These results should be considered when recommending a treatment course for patients with such lesions.

  2. Application of physician-modified fenestrated stent graft in urgent endovascular repair of abdominal aortic aneurysm with hostile neck anatomy

    PubMed Central

    Zeng, Rong; Ye, Wei; Liu, Changwei; Wang, Xuan; Song, Xiaojun; Ni, Leng; Liu, Bao; Li, Yongjun; Zheng, Yuehong

    2016-01-01

    Abstract Background: This study aimed to evaluate the feasibility and effectiveness of the Gore Excluder aortic stent graft (WL Gore & Associates, Inc., Flagstaff, AZ) using the C3 Delivery System after physician modification of fenestration for the urgent treatment of patients with abdominal aortic aneurysm showing hostile neck anatomy. Case summary: Three urgent cases of abdominal aortic aneurysm with hostile neck anatomy symptom with abdominal pain were reported. The same fenestration method was applied to align the target superior mesenteric artery and bilateral renal arteries with 1 scallop and 2 fenestrations, followed by the reconstruction of the target artery using a bare-metal stent or stent graft. Balloon-assisted positioning and image fusion technology were intraoperatively applied to assist the accurate release of the stent graft body. The follow-up periods for all cases exceeded 6 months, showing smooth circulation in the target arteries with no endoleaks. Conclusion: In the absence of other available treatment methods, it is feasible to use a stent graft with physician-modified fenestration for the urgent endovascular repair of abdominal aortic aneurysm with hostile neck anatomy. However, this procedure's long-term efficacy needs to be further investigated. PMID:27861397

  3. Physiologically-relevant measurements of flow through coils and stents: towards improved modeling of endovascular treatment of intracranial aneurysms

    NASA Astrophysics Data System (ADS)

    Barbour, Michael; Levitt, Michael; Geindreau, Christian; Rolland Du Roscoat, Sabine; Johnson, Luke; Chivukula, Keshav; Aliseda, Alberto

    2016-11-01

    The hemodynamic environment in cerebral aneurysms undergoing flow-diverting stent (FDS) or coil embolization treatment plays a critical role in long-term outcomes. Standard modeling approaches to endovascular coils and FDS simplify the complex geometry into a homogenous porous volume or surface through the addition of a Darcy-Brinkman pressure loss term in the momentum equation. The inertial and viscous loss coefficients are typically derived from published in vitro studies of pressure loss across FDS and coils placed in a straight tube, where the only fluid path is across the treatment - an unrealistic representation of treatment apposition in vivo. The pressure drop across FDS and coils in side branch aneurysms located on curved parent vessels is measured. Using PIV, the velocity at the aneurysm neck plane is reconstructed and used to determine loss coefficients for better models of endovascular coils or FDS that account for physiological placement and vessel curvature. These improved models are incorporated into CFD simulations and validated against in vitro model PIV velocity, as well as compared to microCT-based coil/stent-resolving CFD simulations of patient-specific treated aneurysm flow.

  4. Phone and Video-Based Modalities of Central Blinded Adjudication of Modified Rankin Scores in an Endovascular Stroke Trial.

    PubMed

    López-Cancio, Elena; Salvat, Mercè; Cerdà, Neus; Jiménez, Marta; Codas, Javier; Llull, Laura; Boned, Sandra; Cano, Luis M; Lara, Blanca; Molina, Carlos; Cobo, Erik; Dávalos, Antoni; Jovin, Tudor G; Serena, Joaquín

    2015-12-01

    The standard outcome measure in stroke research is modified Rankin scale (mRS) evaluated by local blinded investigators. We aimed to assess feasibility and reliability of 2 central adjudication methods of mRS in the setting of a randomized endovascular stroke trial. This is a secondary analysis derived from the Randomized Trial of Revascularization With Solitaire FR Device Versus Best Medical Therapy in the Treatment of Acute Stroke Due to Anterior Circulation Large Vessel Occlusion Presenting Within Eight Hours of Symptom Onset (REVASCAT) trial cohort. Primary outcome was distribution of mRS at 90 days. Local evaluation was done by certified investigators masked to treatment assignment using structured face-to-face interviews. In addition, central assessment was performed by 2 independent raters via structured phone interview (n=120) and via video recordings of the face-to-face interviews with local investigators (n=106). Interrater agreement was evaluated using kappa and discordance statistics. Sensitivity analyses for the primary end point using different adjudication approaches were performed. Correlation between mRS obtained with each modality and 24-hour follow-up infarct volumes was studied. Using local evaluation as the reference, higher agreement rates were noted with central video than with central phone evaluations (kw 0.92 [0.88-0.96] versus 0.77 [0.72-0.83]). Discrepancies in mRS scoring between local and central raters (phone- and video-based) were similar in both treatment allocation arms. Sensitivity analyses showed benefit of endovascular treatment irrespective of adjudication method, but higher odds ratios were observed with local evaluations. Final infarct volume was similarly correlated with mRS across all 3 evaluation modalities. Central adjudication of mRS is feasible, reducing interrater variability and avoiding potential problems related to lack of blinding. Our findings may have implications in the planning of future randomized acute stroke

  5. Tc-99m Sulfur Colloid Scintigraphy for Detecting Perigraft Flow Following Endovascular Aortic Aneurysm Repair: A Feasibility Study

    SciTech Connect

    Hovsepian, David M.; Siegel, Barry A.; Kimbiris, George; Sicard, Gregorio A.; Allen, Brent T.; Picus, Daniel

    1999-11-15

    Purpose: To determine if scintigraphy with Tc-99m sulfur colloid can be used to detect perigraft flow after stent-graft repair of abdominal aortic aneurysm (AAA). Methods: Twenty-three men and two women aged 56-84 years (mean 71 years) underwent endoluminal AAA repair as part of the EVT Phase II trial [EVT = Endovascular Technologies (Menlo Park, CA, USA)]. Aneurysm size averaged 5.4 cm (range 3-8 cm). Sixteen bifurcated, seven tube, and two aorto-uniiliac grafts were placed. Two days after stent-graft placement, patients underwent both contrast-enhanced computed tomography (CT), including delayed views, and Tc-99m sulfur colloid scintigraphy. Results: Perigraft flow was found in only one patient at completion of angiography. Four additional patients had perigraft flow, discovered during their postoperative follow-up CT. Four patients had leaks at an attachment site and one had retrograde branch flow. Tc-99m sulfur colloid scintigraphy failed to diagnose any of the five leaks prospectively. In two of these patients, however, some abnormal paraaortic activity was noted in retrospect. Conclusion: Tc-99m sulfur colloid scintigraphy was unable to demonstrate endoleak with either rapid flow (attachment site leak) or slow filling (branch flow)

  6. Emergency Endovascular Treatment of an Acute Traumatic Rupture of the Thoracic Aorta Complicated by a Distal Low-Flow Syndrome

    SciTech Connect

    Bruninx, Guy; Wery, Didier; Dubois, Eric; El Nakadi, Badih; Dueren, Eric van; Verhelst, Guy; Delcour, Christian

    1999-11-15

    We report the case of a patient who suffered major trauma following a motorcycle accident that resulted in multiple fractures, bilateral hemopneumothorax, pulmonary contusions, and an isthmic rupture of the aorta with a pseudoaneurysm compressing the descending aorta. This compression was responsible for distal hypotension and low flow, leading to acute renal insufficiency and massive rhabdomyolysis. Due to the critical clinical status of the patient, which prevented any type of open thoracic surgery, endovascular treatment was performed. An initial stent-graft permitted alleviation of the compression and the re-establishment of normal hemodynamic conditions, but its low position did not allow sufficient coverage of the rupture. A second stent-graft permitted total exclusion of the pseudoaneurysm while preserving the patency of the left subclavian artery.

  7. Endovascular repair of traumatic aortic injury using a custom fenestrated endograft to preserve the left subclavian artery.

    PubMed

    Gilani, Ramyar; Ochoa, Lyssa; Wall, Matthew J; Tsai, Peter I; Mattox, Kenneth L

    2011-08-01

    To describe the use of custom fenestrated endografts to preserve left subclavian artery (SCA) flow when requiring coverage during endovascular repair of blunt aortic injury (BAI). A 39-year-old male involved in a motor vehicle accident sustained injuries including intracranial hemorrhage, BAI, and extremity fractures. Immediate neurosurgical intervention was required. Once neurologically stabilized, endovascular repair was performed with a commercially available device modified with a custom fenestration to preserve flow into the left SCA. Serial follow-up CT angiography (CTA) demonstrates satisfactory repair with prograde left SCA flow and no evidence of endoleak. Left SCA coverage is often required for successful endovascular repair of BAI. A subgroup of patients who undergo left SCA coverage will require revascularization. The use of custom fenestrated endografts for preserving left SCA during thoracic endovascular aortic repair (TEVAR) for BAI is an innovative and feasible option in patients who require revascularization.

  8. Endovascular treatment of cerebral venous thrombosis: Contemporary multicenter experience

    PubMed Central

    Mokin, Maxim; Lopes, Demetrius K; Binning, Mandy J; Veznedaroglu, Erol; Liebman, Kenneth M; Arthur, Adam S; Doss, Vinodh T; Levy, Elad I

    2015-01-01

    Endovascular therapy of cerebral venous thrombosis using modern approaches to intracranial recanalization, such as stent retrievers and aspiration thrombectomy, is not well described. We performed a retrospective review of data for consecutive patients with venous sinus thrombosis who underwent endovascular treatment between 1 January 2010 and 31 December 2013 at participating institutions. We identified a total of 13 patients with a diagnosis of cerebral venous thrombosis. The most frequently utilized type of endovascular intervention was the Penumbra aspiration system (Penumbra Inc., Alameda, California, USA) (nine cases), followed by local infusion of tissue plasminogen activator (bolus and/or drip in six cases) and stent retrievers (Solitaire FR (Covidien, Irvine, California, USA) in three cases and Trevo (Stryker, Kalamazoo, Michigan, USA) in one case). Overall, multimodality treatment (two or more different types of devices or approaches) was performed in 62% of cases. Follow-up data were available for 11 patients; of those, five had a favorable clinical outcome (defined as modified Rankin Scale score of 0–2) and three patients died. Various endovascular approaches are utilized in current clinical practice. A multimodal approach to endovascular therapy for the treatment of cerebral venous thrombosis resulted in partial or complete restoration of flow in all cases, yet the mortality rate of 27% indicates the need for improvement in recanalization strategies for this disorder. PMID:26055685

  9. Successful endovascular treatment of a growing megadolichoectasic vertebrobasilar artery aneurysm by flow diversion using the "diverter-in-stent" technique.

    PubMed

    Cohen, José E; Gomori, John M; Moscovici, Samuel; Itshayek, Eyal

    2012-01-01

    Giant dolichoectatic and fusiform aneurysms of the vertebrobasilar artery are among the most difficult and dangerous aneurysms to treat. Conservative management may be reasonable in asymptomatic elderly patients. Nevertheless, due to the frequent presence of mass effect on the brainstem and the risks of thromboembolic events and rupture, these aneurysms often demand treatment rather than observation. With the advancement of endovascular techniques some of these lesions have become treatable without the high morbidity and mortality rates associated with open surgical treatment. When dealing with giant, progressively enlarging symptomatic aneurysms, more limited therapeutic alternatives are available. The authors present a case of a growing megadolichoectatic vertebrobasilar artery aneurysm causing major disability due to increasing mass effect in a 51-year-old man. The aneurysm was treated with flow diversion by placing multiple telescoped stents and diverters ("diverter-in-stent" technique), achieving thrombosis of the aneurysm and reduction of the mass effect on the brainstem, with neurological improvement. The successful clinical and angiographic results observed in our case of giant dolichoectasic vertebrobasilar aneurysm contribute to the literature on giant aneurysms treated by means of flow diversion. Copyright © 2011 Elsevier Ltd. All rights reserved.

  10. Modified Laminar Flow Biological Safety Cabinet

    PubMed Central

    Mcgarrity, Gerard J.; Coriell, Lewis L.

    1974-01-01

    Tests are reported on a modified laminar flow biological safety cabinet in which the return air plenum that conducts air from the work area to the high efficiency particulate air filters is under negative pressure. Freon gas released inside the cabinet could not be detected outside by a freon gas detection method capable of detecting 10-6 cc/s. When T3 bacteriophage was aerosolized 5 cm outside the front opening in 11 tests, no phage could be detected inside the cabinet with the motor-filter unit in operation. An average of 2.8 × 105 plaque-forming units (PFU)/ft3 (ca. 0.028 m3) were detected with the motor-filter unit not in operation, a penetration of 0.0%. Aerosolization 5 cm inside the cabinet yielded an average of 10 PFU/ft3 outside the cabinet with the motor-filter unit in operation and an average of 4.1 × 105 PFU/ft3 with the motor-filter unit not in operation, a penetration of 0.002%. These values are the same order of effectiveness as the positive-pressure laminar flow biological safety cabinets previously tested. The advantages of the negative-pressure return plenum design include: (i) assurance that if cracks or leaks develop in the plenum it will not lead to discharge of contaminated air into the laboratory; and (ii) the price is lower due to reduced manufacturing costs. Images PMID:4420479

  11. Early Experience in the Treatment of Intra-Cranial Aneurysms by Endovascular Flow Diversion: A Multicentre Prospective Study

    PubMed Central

    Byrne, James V.; Beltechi, Radu; Yarnold, Julia A.; Birks, Jacqueline; Kamran, Mudassar

    2010-01-01

    Introduction Flow diversion is a new approach to the endovascular treatment of intracranial aneurysms which uses a high density mesh stent to induce sac thrombosis. These devices have been designed for the treatment of complex shaped and large size aneurysms. So far published safety and efficacy data on this approach is sparse. Material and Methods Over 8 months, standardized clinical and angiographic data were collected on 70 patients treated with a flow diverter device (SILK flow diverter (SFD)) in 18 centres worldwide. Treatment and early follow up details were audited centrally. SFDs were deployed alone in 57 (81%) or with endosaccular coils in 10 (14%) aneurysms, which included: 44 (63%) saccular, 26 (37%) fusiform shapes and 18 (26%) small, 37 (53%) large, 15 (21%) giant sizes. Treatment outcome data up to 30 days were reported for all patients, with clinical (50 patients) and imaging (49 patients) follow up (median 119 days) data available. Results Difficulties in SFD deployment were reported in 15 (21%) and parent artery thrombosis in 8 (11%) procedures. Procedural complications caused stroke in 1 and serious extracranial bleeding in 3 patients; 2 of whom developed fatal pneumonias. Delayed worsening of symptoms occurred in 5 patients (3 transient, 1 permanent neurological deficit, and 1 death) and fatal aneurysm bleeding in 1 patient. Overall permanent morbidity rates were 2 (4%) and mortality 4 (8%). Statistical analysis revealed no significant association between complications and variables related to treated aneurysm morphology or rupture status. Conclusion This series is the largest reporting outcome of the new treatment approach and provides data for future study design. Procedural difficulties in SFD deployment were frequent and anti-thrombosis prophylaxis appears to reduce the resulting clinical sequelae, but at the cost of morbidity due to extracranial bleeding. Delayed morbidity appears to be a consequence of the new approach and warrants care in

  12. Acute Endovascular Treatment (< 48 Hours) of Uncoilable Ruptured Aneurysms at Non-Branching Sites Using Silk Flow-Diverting Devices

    PubMed Central

    Causin, F.; Pascarella, R.; Pavesi, G.; Marasco, R.; Zambon, G.; Battaglia, R.; Munari, M.

    2011-01-01

    Summary A blood blister-like (BBL) or dissecting aneurysm should be carefully considered if located at a non-branching site of the supra-clinoid internal carotid artery (ICA). Several surgical and endovascular treatment methods have been proposed but they all carry a relatively high risk of morbidity and mortality. This study evaluated the effectiveness of a novel Silk flow-diverting device (SFD) placed in the early acute stage. Three patients presenting with acute subarachnoid haemorrhage caused by small blister-like aneurysms of the carotid siphon were treated within 48 hours after admission by placement of SFDs. More than one device was placed to cover the lesion. None of the patients were premedicated and started anti-platelet therapy during the procedure. All aneurysms were successfully occluded. A good outcome was observed in two out of three treated patients. No thromboembolic or haemorrhagic event occurred during or after the procedures, or during follow-up (6-14 months). SFD prevented rebleeding and the use of these devices could be proposed as an option to treat fragile uncoilable BBL aneurysms, even in the early acute phase without anti-platelet premedication. Larger studies and long-terms results are necessary. PMID:22005700

  13. Modified Numerical Simulation Model of Blood Flow in Bend

    PubMed Central

    Liu, X; Zhou, X; Hao, X; Sang, X

    2015-01-01

    ABSTRACT The numerical simulation model of blood flow in bend is studied in this paper. The curvature modification is conducted for the blood flow model in bend to obtain the modified blood flow model in bend. The modified model is verified by U tube. By comparing the simulation results with the experimental results obtained by measuring the flow data in U tube, it was found that the modified blood flow model in bend can effectively improve the prediction accuracy of blood flow data affected by the curvature effect. PMID:27398727

  14. Combined surgical and endovascular treatment of complex high-flow conus medullaris arteriovenous fistula associated with Parkes Weber syndrome: case report.

    PubMed

    Bagherpour, Arya N; Rodriguez, Gustavo J; Moorthy, Chetan; Trier, Todd T; Maud, Alberto

    2016-08-01

    Parkes Weber syndrome (PWS) is a congenital overgrowth disorder characterized by unilateral limb and axial hypertrophy, capillary malformations of the skin, and high-flow arteriovenous fistulas (AVFs). Spinal AVFs in the setting of PWS are challenging vascular lesions that often contain multiple arteriovenous (AV) shunts. The present case report highlights an adolescent girl with PWS who presented with a ruptured complex high-flow conus medullaris AVF. She was successfully treated with endovascular embolization and microsurgery. At the 2-year follow-up, the patient remained free of neurological symptoms and had no recurrence of the vascular malformation.

  15. Flow Changes after Endovascular Treatment of a Wide-Neck Anterior Communicating Artery Aneurysm by using X-configured Kissing Stents (Cross-Kissing Stents) Technique

    SciTech Connect

    Zelenak, Kamil; Zelenakova, Jana; DeRiggo, Julius; Kurca, Egon; Boudny, Jaroslav; Polacek, Hubert

    2011-12-15

    Endovascular treatment for a wide-neck anterior communicating artery (AcomA) aneurysm remains technically challenging. Stent-assisted embolization has been proposed as an alternative of treatment of complex aneurysms. The X-configuration double-stent-assisted technique was used to achieve successful coiling of wide-neck AcomA aneurysm. Implanted stent can alter intra-arterial flow. Follow-up angiograms 4 months later showed flow changes due to used X-technique of stents implantation and filling of the anterior cerebral artery from the opposite internal carotid artery.

  16. The silk flow-diverting stent in the endovascular treatment of complex intracranial aneurysms: technical aspects and midterm results in 24 consecutive patients.

    PubMed

    Tähtinen, Olli I; Manninen, Hannu I; Vanninen, Ritva L; Seppänen, Janne; Niskakangas, Tero; Rinne, Jaakko; Keski-Nisula, Leo

    2012-03-01

    The flow-diverting stent is a new option in endovascular therapy specifically designed for the endovascular reconstruction of a segmentally diseased artery. The safety of flow-diverting stents is still equivocal. To evaluate the technical aspects, thromboembolic events, adjunctive therapies, and midterm results in patients with complex intracranial aneurysms treated with a flow-diverting stent (Silk; Balt Extrusion, Montmorency, France). We retrospectively examined angiographic images and clinical reports of 24 consecutive patients (29 stents) treated (n = 23) or attempted to treat (n = 1) with a flow-diverting device in 2 Finnish centers between March 2009 and October 2010. The primary technical success rate was 67% (16/24). Adjunctive therapies were required in 6 (25%) patients, including 4 cases where intra-arterial abciximab was administered for the treatment of intraprocedural thromboembolic events. Technique-related complication rate and the 30-day mortality rate were each 4% (1/24). Follow-up imaging revealed 1 case of delayed in-stent thrombosis resulting in permanent disability of the patient, 1 asymptomatic occlusion, and 1 asymptomatic stenosis of the stented artery. Complete occlusion of the aneurysm with fully patent parent artery was observed in 16 of the 23 aneurysms (70%) where follow-up images were available. Many previously untreatable cerebral aneurysms may be successfully treated with the Silk flow-diverting stent, but the associated risk of thromboembolic events is justifiable only if conventional endovascular or surgical treatment options are not applicable. Perioperative thromboembolic events should be prepared for and treated without unnecessary delays because they frequently respond to adjunctive medical therapy.

  17. Gene Flow in Genetically Modified Wheat

    PubMed Central

    Rieben, Silvan; Kalinina, Olena; Schmid, Bernhard; Zeller, Simon L.

    2011-01-01

    Understanding gene flow in genetically modified (GM) crops is critical to answering questions regarding risk-assessment and the coexistence of GM and non-GM crops. In two field experiments, we tested whether rates of cross-pollination differed between GM and non-GM lines of the predominantly self-pollinating wheat Triticum aestivum. In the first experiment, outcrossing was studied within the field by planting “phytometers” of one line into stands of another line. In the second experiment, outcrossing was studied over distances of 0.5–2.5 m from a central patch of pollen donors to adjacent patches of pollen recipients. Cross-pollination and outcrossing was detected when offspring of a pollen recipient without a particular transgene contained this transgene in heterozygous condition. The GM lines had been produced from the varieties Bobwhite or Frisal and contained Pm3b or chitinase/glucanase transgenes, respectively, in homozygous condition. These transgenes increase plant resistance against pathogenic fungi. Although the overall outcrossing rate in the first experiment was only 3.4%, Bobwhite GM lines containing the Pm3b transgene were six times more likely than non-GM control lines to produce outcrossed offspring. There was additional variation in outcrossing rate among the four GM-lines, presumably due to the different transgene insertion events. Among the pollen donors, the Frisal GM line expressing a chitinase transgene caused more outcrossing than the GM line expressing both a chitinase and a glucanase transgene. In the second experiment, outcrossing after cross-pollination declined from 0.7–0.03% over the test distances of 0.5–2.5 m. Our results suggest that pollen-mediated gene flow between GM and non-GM wheat might only be a concern if it occurs within fields, e.g. due to seed contamination. Methodologically our study demonstrates that outcrossing rates between transgenic and other lines within crops can be assessed using a phytometer approach and

  18. Endovascular treatment of blister aneurysms.

    PubMed

    Peitz, Geoffrey W; Sy, Christopher A; Grandhi, Ramesh

    2017-06-01

    Blister aneurysms are rare cerebrovascular lesions for which the treatment methods are reviewed here, with a focus on endovascular options. The reported pathogenesis of blister aneurysms varies, and hemodynamic stress, arterial dissection, and arteriosclerotic ulceration have all been described. There is consensus on the excessive fragility of blister aneurysms and their parent vessels, which makes clipping technically difficult. Open surgical treatment is associated with high rates of complications, morbidity, and mortality; endovascular treatment is a promising alternative. Among endovascular treatment options, deconstructive treatment has been associated with higher morbidity compared with reconstructive methods such as direct embolization, stent- or balloon-assisted direct embolization, stent monotherapy, and flow diversion. Flow diversion has been associated with higher technical success rates and similar clinical outcomes compared with non-flow diverting treatment methods. However, delayed aneurysm occlusion and the need for antiplatelet therapy are potential drawbacks to flow diversion that must be considered when choosing among treatment methods for blister aneurysms.

  19. 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. ...

  20. Tandem symptomatic internal carotid artery and persistent hypoglossal artery stenosis treated by endovascular stenting and flow reversal

    PubMed Central

    Eller, Jorge L; Jahshan, Shady; Dumont, Travis M; Kan, Peter; Siddiqui, Adnan H

    2013-01-01

    Persistence of the hypoglossal artery into adulthood is a rare vascular anomaly and, when present, provides the predominant vascular supply to the posterior circulation. We describe a case of vertebrobasilar insufficiency associated with severe high-grade stenosis of the persistent hypoglossal artery and tandem stenosis of the proximal ipsilateral internal carotid artery, treated by an endovascular approach. The unique anatomical and technical challenges associated with this case are reviewed in detail. PMID:23709141

  1. Modified Beer-Lambert law for blood flow

    PubMed Central

    Baker, Wesley B.; Parthasarathy, Ashwin B.; Busch, David R.; Mesquita, Rickson C.; Greenberg, Joel H.; Yodh, A. G.

    2014-01-01

    We develop and validate a Modified Beer-Lambert law for blood flow based on diffuse correlation spectroscopy (DCS) measurements. The new formulation enables blood flow monitoring from temporal intensity autocorrelation function data taken at single or multiple delay-times. Consequentially, the speed of the optical blood flow measurement can be substantially increased. The scheme facilitates blood flow monitoring of highly scattering tissues in geometries wherein light propagation is diffusive or non-diffusive, and it is particularly well-suited for utilization with pressure measurement paradigms that employ differential flow signals to reduce contributions of superficial tissues. PMID:25426330

  2. Modified Beer-Lambert law for blood flow.

    PubMed

    Baker, Wesley B; Parthasarathy, Ashwin B; Busch, David R; Mesquita, Rickson C; Greenberg, Joel H; Yodh, A G

    2014-11-01

    We develop and validate a Modified Beer-Lambert law for blood flow based on diffuse correlation spectroscopy (DCS) measurements. The new formulation enables blood flow monitoring from temporal intensity autocorrelation function data taken at single or multiple delay-times. Consequentially, the speed of the optical blood flow measurement can be substantially increased. The scheme facilitates blood flow monitoring of highly scattering tissues in geometries wherein light propagation is diffusive or non-diffusive, and it is particularly well-suited for utilization with pressure measurement paradigms that employ differential flow signals to reduce contributions of superficial tissues.

  3. Modified Beer-Lambert law for blood flow

    NASA Astrophysics Data System (ADS)

    Baker, Wesley B.; Parthasarathy, Ashwin B.; Busch, David R.; Mesquita, Rickson C.; Greenberg, Joel H.; Yodh, A. G.

    2015-03-01

    The modified Beer-Lambert law is among the most widely used approaches for analysis of near-infrared spectroscopy (NIRS) reflectance signals for measurements of tissue blood volume and oxygenation. Briefly, the modified Beer-Lambert paradigm is a scheme to derive changes in tissue optical properties based on continuous-wave (CW) diffuse optical intensity measurements. In its simplest form, the scheme relates differential changes in light transmission (in any geometry) to differential changes in tissue absorption. Here we extend this paradigm to the measurement of tissue blood flow by diffuse correlation spectroscopy (DCS). In the new approach, differential changes of the intensity temporal auto-correlation function at a single delay-time are related to differential changes in blood flow. The key theoretical results for measurement of blood flow changes in any tissue geometry are derived, and we demonstrate the new method to monitor cerebral blood flow in a pig under conditions wherein the semi-infinite geometry approximation is fairly good. Specifically, the drug dinitrophenol was injected in the pig to induce a gradual 200% increase in cerebral blood flow, as measured with MRI velocity flow mapping and by DCS. The modified Beer-Lambert law for flow accurately recovered these flow changes using only a single delay-time in the intensity auto-correlation function curve. The scheme offers increased DCS measurement speed of blood flow. Further, the same techniques using the modified Beer-Lambert law to filter out superficial tissue effects in NIRS measurements of deep tissues can be applied to the DCS modified Beer-Lambert law for blood flow monitoring of deep tissues.

  4. Modifying shale oil to improve flow characteristics

    SciTech Connect

    Seitzer, W.H.; Lovell, P.F.

    1982-05-01

    Shale oil, which forms a viscous, wax slurry below 25 C, was treated in several different ways to try to improve its flow characteristics as measured in a concentric cylinder viscometer. Removing the wax does not greatly improve the pumpability of the oil. Hydrotreatment of the whole oil to take out nitrogen, sulfur, and oxygen can lower the viscosity by a factor of five or more, even though the pour point is not greatly affected. Apparently hydrogenolysis of the nitrogen, sulfur, and oxygen lowers the molecular weight of the oil without much modification of the paraffinic wax. The pour point of the shale oil can be decreased with various commercial pour improvers. Sometimes an accompanying drop in viscosity is observed, but most of this decrease is not stable to shear in the viscometer.

  5. Functional Flows in Modified Riverscapes: Hydrographs, Habitats and Opportunities

    NASA Astrophysics Data System (ADS)

    Yarnell, S. M.; Whipple, A. A.; Beller, E.; Dahm, C.; Enright, C.; Goodwin, P.; Petts, G.; Viers, J. H.

    2014-12-01

    Building on previous environmental flow discussions and a growing recognition that geomorphic and ecological processes are inherent to river functionality and biodiversity, we propose a functional flows approach to managing rivers in contemporary modified riverscapes. The approach focuses on retaining specific functional flows or process-based components of the hydrograph in managed systems, including: peak magnitude flows, recession (seasonal transition) flows, dry season low flows, wet season initiation flows, and interannual variability based on climate. Using a series of case studies and specific examples, we illustrate the importance of each key functional flow. In order to maximize the functionality of these flows and thereby maximize aquatic diversity, restoration of channel-floodplain connectivity and sediment transport processes must be enhanced in both space and time. We further provide considerations for managers that include five guiding principles for developing a functional flows approach or incorporating functional flows into existing environmental flow frameworks. We suggest this approach allows for the development of flow regimes that encompass ecosystem processes alongside varied human needs and can be applied in an adaptive management framework allowing for adjustment in non-stationary river environments.

  6. Hydrodynamic Study of a Submerged Entry Nozzle with Flow Modifiers

    NASA Astrophysics Data System (ADS)

    Real-Ramirez, Cesar Augusto; Miranda-Tello, Raul; Carvajal-Mariscal, Ignacio; Sanchez-Silva, Florencio; Gonzalez-Trejo, Jesus

    2017-04-01

    The fluid flow modifier technology for continuous casting process was evaluated through numerical simulations and physical experiments in this work. In the casting of steel into the mold, the process presents liquid surface instabilities which extend along the primary cooling stage. By the use of trapezoid elements installed on the external walls of the submerged nozzle, it was observed that it is possible to obtain symmetry conditions at the top of the mold and prevent high level fluctuations. The flow modifiers have equidistant holes in the submerged surface to reduce the velocity of the liquid surface by energy and mass transfer between the generated quadrants. A flow modifier drilled with a 25 pct of the submerged surface provides stability in the mold and structural stability of the proposal is guaranteed.

  7. Hydrodynamic Study of a Submerged Entry Nozzle with Flow Modifiers

    NASA Astrophysics Data System (ADS)

    Real-Ramirez, Cesar Augusto; Miranda-Tello, Raul; Carvajal-Mariscal, Ignacio; Sanchez-Silva, Florencio; Gonzalez-Trejo, Jesus

    2016-12-01

    The fluid flow modifier technology for continuous casting process was evaluated through numerical simulations and physical experiments in this work. In the casting of steel into the mold, the process presents liquid surface instabilities which extend along the primary cooling stage. By the use of trapezoid elements installed on the external walls of the submerged nozzle, it was observed that it is possible to obtain symmetry conditions at the top of the mold and prevent high level fluctuations. The flow modifiers have equidistant holes in the submerged surface to reduce the velocity of the liquid surface by energy and mass transfer between the generated quadrants. A flow modifier drilled with a 25 pct of the submerged surface provides stability in the mold and structural stability of the proposal is guaranteed.

  8. Endovascular treatment with primary stenting of inferior cava vein torsion following orthotopic liver transplantation with modified piggyback technique.

    PubMed

    Ferro, Carlo; Andorno, Enzo; Guastavino, Andrea; Rossi, Umberto G; Seitun, Sara; Bovio, Giulio; Valente, Umberto

    2014-03-01

    This study was undertaken to evaluate primary stenting in patients with inferior vena cava torsion after orthotopic liver transplantation performed with modified piggyback technique. From November 2003 to October 2010, six patients developed clinical, laboratory and imaging findings suggestive of caval stenosis, after a mean period of 21 days from an orthotopic liver transplantation performed with modified piggyback technique. Vena cavography showed stenosis due to torsion of the inferior vena cava at the anastomoses and a significant caval venous pressure gradient. All patients were treated with primary stenting followed by in-stent angioplasty in three cases. In all patients, the stents were successfully positioned at the caval anastomosis and the venous gradient pressure fell from a mean value of 10 to 2 mmHg. Signs and symptoms resolved in all six patients. One patient died 3 months after stent placement due to biliary complications. No evidence of recurrence or complications was noted during the follow-up (mean 49 months). Primary stenting of inferior vena cava stenosis due to torsion of the anastomoses in patients receiving orthotopic liver transplantation with modified piggyback technique is a safe, effective and durable treatment.

  9. A multimodality imaging approach for guiding a modified endovascular coil embolization of a single intrahepatic portosystemic shunt in dogs.

    PubMed

    Knapp, Teja; Navalòn, Iolanda; Medda, Massimo; Pradelli, Danitza; Borgonovo, Simone; Crosta, Cristina; Bussadori, Claudio Maria

    2015-12-01

    Intrahepatic portosystemic shunts (IHPSS) in dogs are aberrant vascular anomalies that connect the portal and the systemic venous vessels. In most of the patients, the surgical approach is unfavourable due to the difficulties in isolating the IHPSS, making the option of a percutaneous transvenous coil embolization (PTCE) one of the safer occlusive procedures. This study describes the treatment of eight dogs with a single IHPSS using a multimodality imaging approach to guide the modified PTCE procedure. This new technique results in a decrease of 71% of the time of the entire procedure with the reduction of 91% in the time required involved the IHPSS identification and in the fluoroscopy exposure time avoiding the need for iodinated contrast agents during the procedure. Moreover, the placement of the catheter before the caval stent ensures its greater stability, enhancing the procedural safety in the phase when the coils are released and avoiding the risk of their dislocation.

  10. Pediatric high-flow, cervical spinal, macro-arteriovenous fistula, treated with the endovascular cotton candy glue injection technique.

    PubMed

    Iizuka, Yuo; Kohda, Ehiichi; Tsutsumi, Yoshiyuki; Masaki, Hidekazu; Nosaka, Shunsuke; Morota, Nobuhito; Kobayashi, Shigeki; Konishi, Yoshifumi

    2010-11-01

    A 3-year-old boy presented to our hospital with progressive neurological deficits. Spinal magnetic resonance imaging (MRI) revealed a perimedullary macro-arteriovenous fistula (PMAVF) resulting in a large venous pouch within the parenchyma of the lower cervical spinal cord. Transarterial varix embolization of the fistula from the venous side was performed using N-butyl cyanoacrylate with tantalum powder. Postembolization angiography confirmed obliteration of the fistula, and MRI revealed thrombosis and reduction in size of the venous component. The patient's clinical symptoms were reduced dramatically following the intervention, and no neurological complications occurred due to the treatment. The prognosis of spinal PMAVF depends primarily on the presence of medullar signs and symptoms and on time to treatment. The volume of the venous pouch after the intervention was markedly reduced, and complete clinical recovery was obtained. Urgent endovascular intervention, as seen in this case, is considered first-line therapy and aims to decrease the risk of neurological sequela.

  11. Endovascular treatment of chronic cerebro spinal venous insufficiency in patients with multiple sclerosis modifies circulating markers of endothelial dysfunction and coagulation activation: a prospective study.

    PubMed

    Napolitano, Mariasanta; Bruno, Aldo; Mastrangelo, Diego; De Vizia, Marcella; Bernardo, Benedetto; Rosa, Buonagura; De Lucia, Domenico

    2014-10-01

    We performed a monocentric observational prospective study to evaluate coagulation activation and endothelial dysfunction parameters in patients with multiple sclerosis undergoing endovascular treatment for cerebro-spinal-venous insufficiency. Between February 2011 and July 2012, 144 endovascular procedures in 110 patients with multiple sclerosis and chronical cerebro-spinal venous insufficiency were performed and they were prospectively analyzed. Each patient was included in the study according to previously published criteria, assessed by the investigators before enrollment. Endothelial dysfunction and coagulation activation parameters were determined before the procedure and during follow-up at 1, 3, 6, 9, 12, 15 and 18 months after treatment, respectively. After the endovascular procedure, patients were treated with standard therapies, with the addition of mesoglycan. Fifty-five percent of patients experienced a favorable outcome of multiple sclerosis within 1 month after treatment, 25% regressed in the following 3 months, 24.9% did not experience any benefit. In only 0.1% patients, acute recurrence was observed and it was treated with high-dose immunosuppressive therapy. No major complications were observed. Coagulation activation and endothelial dysfunction parameters were shown to be reduced at 1 month and stable up to 12-month follow-up, and they were furthermore associated with a good clinical outcome. Endovascular procedures performed by a qualified staff are well tolerated; they can be associated with other currently adopted treatments. Correlations between inflammation, coagulation activation and neurodegenerative disorders are here supported by the observed variations in plasma levels of markers of coagulation activation and endothelial dysfunction.

  12. Hydrodynamic modeling of granular flows in a modified Couette cell.

    PubMed

    Jop, Pierre

    2008-03-01

    We present simulations of granular flows in a modified Couette cell, using a continuum model recently proposed for dense granular flows. Based on a friction coefficient, which depends on an inertial number, the model captures the positions of the wide shear bands. We show that a smooth transition in velocity-profile shape occurs when the height of the granular material is increased, leading to a differential rotation of the central part close to the surface. The numerical predictions are in qualitative agreement with previous experimental results. The model provides predictions for the increase of the shear band width when the rotation rate is increased.

  13. CONDIF - A modified central-difference scheme for convective flows

    NASA Technical Reports Server (NTRS)

    Runchal, Akshai K.

    1987-01-01

    The paper presents a method, called CONDIF, which modifies the CDS (central-difference scheme) by introducing a controlled amount of numerical diffusion based on the local gradients. The numerical diffusion can be adjusted to be negligibly low for most problems. CONDIF results are significantly more accurate than those obtained from the hybrid scheme when the Peclet number is very high and the flow is at large angles to the grid.

  14. CONDIF - A modified central-difference scheme for convective flows

    NASA Technical Reports Server (NTRS)

    Runchal, Akshai K.

    1987-01-01

    The paper presents a method, called CONDIF, which modifies the CDS (central-difference scheme) by introducing a controlled amount of numerical diffusion based on the local gradients. The numerical diffusion can be adjusted to be negligibly low for most problems. CONDIF results are significantly more accurate than those obtained from the hybrid scheme when the Peclet number is very high and the flow is at large angles to the grid.

  15. Endovascular Therapy in Trauma

    DTIC Science & Technology

    2014-11-23

    Vascular Surgery . J Vasc Surg. 2011;53:187–92. 12. Piffaretti G, Benedetto F, Menegolo M, et al. Outcomes of end- ovascular repair for blunt thoracic...techniques to manage various forms: vascular injury, bleeding, and shock; including injury patterns in which an endovascular approach is established...and scenarios in which it is nascent and evolving. Keywords Vascular trauma · Endovascular repair · Catheter-based approach · Endovascular balloon

  16. Preservation of hypogastric artery blood flow during endovascular aneurysm repair of an abdominal aortic aneurysm with bilateral common and internal iliac artery involvement: utilization of off-the-shelf stent-graft components.

    PubMed

    Riesenman, Paul J; Ricotta, Joseph J; Veeraswamy, Ravi K

    2012-01-01

    A 72-year-old male presented with a 7.4-cm abdominal aortic aneurysm with bilateral common and internal iliac involvement. To maintain pelvic perfusion, preservation of the patient's left hypogastric artery (HA) was pursued. Two weeks after right HA embolization, endovascular repair of the patient's aneurysms was performed using a branched endograft approach. A 22-mm main body bifurcated endograft was unsheathed and the proximal covered stent was removed. The contralateral gate was preloaded with a wire and catheter. The device was resheathed and placed in the left common iliac artery. The preloaded wire in the contralateral gate was snared from the right side, establishing through-and-through femoral access. A contralateral femoral sheath was advanced up and over the aortic bifurcation from the right side into the contralateral gate of the bifurcated endograft. The repair was bridged to the left HA using a balloon-expandable stent-graft, followed by standard endovascular abdominal aortic aneurysm repair. Completion angiography demonstrated exclusion of patient's aneurysms, without evidence of endoleak, and maintenance of pelvic blood flow through the left HA. The patient recovered without complication and was discharged home on postoperative day 4. This technique illustrates the technical feasibility of using a preloaded commercially available endograft to preserve HA blood flow and maintain pelvic perfusion during endovascular aortic aneurysm repair. Copyright © 2012 Annals of Vascular Surgery Inc. Published by Elsevier Inc. All rights reserved.

  17. Angiographic analysis for phantom simulations of endovascular aneurysm treatments with a new fully retrievable asymmetric flow diverter

    NASA Astrophysics Data System (ADS)

    Yoganand, Aradhana; Wood, Rachel P.; Jimenez, Carlos; Siddiqui, Adnan; Snyder, Kenneth; Setlur Nagesh, S. V.; Bednarek, D. R.; Rudin, S.; Baier, Robert; Ionita, Ciprian N.

    2015-03-01

    Digital Subtraction Angiography (DSA) is the main diagnostic tool for intracranial aneurysms (IA) flow-diverter (FD) assisted treatment. Based on qualitative contrast flow evaluation, interventionists decide on subsequent steps. We developed a novel fully Retrievable Asymmetric Flow-Diverter (RAFD) which allows controlled deployment, repositioning and detachment achieve optimal flow diversion. The device has a small low porosity or solid region which is placed such that it would achieve maximum aneurysmal in-jet flow deflection with minimum impairment to adjacent vessels. We tested the new RAFD using a flow-loop with an idealized and a patient specific IA phantom in carotid-relevant physiological conditions. We positioned the deflection region at three locations: distally, center and proximally to the aneurysm orifice and analyzed aneurysm dome flow using DSA derived maps for mean transit time (MTT) and bolus arrival times (BAT). Comparison between treated and untreated (control) maps quantified the RAFD positioning effect. Average MTT, related to contrast presence in the aneurysm dome increased, indicating flow decoupling between the aneurysm and parent artery. Maximum effect was observed in the center and proximal position (~75%) of aneurysm models depending on their geometry. BAT maps, correlated well with inflow jet direction and magnitude. Reduction and jet dispersion as high as about 50% was observed for various treatments. We demonstrated the use of DSA data to guide the placement of the RAFD and showed that optimum flow diversion within the aneurysm dome is feasible. This could lead to more effective and a safer IA treatment using FDs.

  18. GENERAL: A modified weighted probabilistic cellular automaton traffic flow model

    NASA Astrophysics Data System (ADS)

    Zhuang, Qian; Jia, Bin; Li, Xin-Gang

    2009-08-01

    This paper modifies the weighted probabilistic cellular automaton model (Li X L, Kuang H, Song T, et al 2008 Chin. Phys. B 17 2366) which considered a diversity of traffic behaviors under real traffic situations induced by various driving characters and habits. In the new model, the effects of the velocity at the last time step and drivers' desire for acceleration are taken into account. The fundamental diagram, spatial-temporal diagram, and the time series of one-minute data are analyzed. The results show that this model reproduces synchronized flow. Finally, it simulates the on-ramp system with the proposed model. Some characteristics including the phase diagram are studied.

  19. Modified sequential fully implicit scheme for compositional flow simulation

    NASA Astrophysics Data System (ADS)

    Moncorgé, A.; Tchelepi, H. A.; Jenny, P.

    2017-05-01

    The fully implicit (FI) method is widely used for numerical modeling of multiphase flow and transport in porous media. The FI method is unconditionally stable, but that comes at the cost of a low-order approximation and high computational cost. The FI method entails iterative linearization and solution of fully-coupled linear systems with mixed elliptic/hyperbolic character. However, in methods that treat the near-elliptic (flow) and hyperbolic (transport) separately, such as multiscale formulations, sequential solution strategies are used to couple the flow (pressures and velocities) and the transport (saturations/compositions). The most common sequential schemes are: the implicit pressure explicit saturation (IMPES), and the sequential fully implicit (SFI) schemes. Problems of practical interest often involve tightly coupled nonlinear interactions between the multiphase flow and the multi-component transport. For such problems, the IMPES approach usually suffers from prohibitively small timesteps in order to obtain stable numerical solutions. The SFI method, on the other hand, does not suffer from a temporal stability limit, but the convergence rate can be extremely slow. This slow convergence rate of SFI can offset the gains obtained from separate and specialized treatments of the flow and transport problems. In this paper, we analyze the nonlinear coupling between flow and transport for compressible, compositional systems with complex interphase mass transfer. We isolate the nonlinear effects related to transmissibility and compressibility from those due to interphase mass transfer, and we propose a modified SFI (m-SFI) method. The new scheme involves enriching the 'standard' pressure equation with coupling between the pressure and the saturations/compositions. The modification resolves the convergence problems associated with SFI and provides a strong basis for using sequential formulations for general-purpose simulation. For a wide parameter range, we show

  20. Angiographic analysis for phantom simulations of endovascular aneurysm treatments with a new fully retrievable asymmetric flow diverter

    PubMed Central

    Yoganand, Aradhana; Wood, Rachel P.; Jimenez, Carlos; Siddiqui, Adnan; Snyder, Kenneth; Nagesh, S.V. Setlur; Bednarek, D.R.; Rudin, S; Baier, Robert; Ionita, Ciprian N

    2015-01-01

    Digital Subtraction Angiography (DSA) is the main diagnostic tool for intracranial aneurysms (IA) flow-diverter (FD) assisted treatment. Based on qualitative contrast flow evaluation, interventionists decide on subsequent steps. We developed a novel fully Retrievable Asymmetric Flow-Diverter (RAFD) which allows controlled deployment, repositioning and detachment achieve optimal flow diversion. The device has a small low porosity or solid region which is placed such that it would achieve maximum aneurysmal in-jet flow deflection with minimum impairment to adjacent vessels. We tested the new RAFD using a flow-loop with an idealized and a patient specific IA phantom in carotid-relevant physiological conditions. We positioned the deflection region at three locations: distally, center and proximally to the aneurysm orifice and analyzed aneurysm dome flow using DSA derived maps for mean transit time (MTT) and bolus arrival times (BAT). Comparison between treated and untreated (control) maps quantified the RAFD positioning effect. Average MTT, related to contrast presence in the aneurysm dome increased, indicating flow decoupling between the aneurysm and parent artery. Maximum effect was observed in the center and proximal position (~75%) of aneurysm models depending on their geometry. BAT maps, correlated well with inflow jet direction and magnitude. Reduction and jet dispersion as high as about 50% was observed for various treatments. We demonstrated the use of DSA data to guide the placement of the RAFD and showed that optimum flow diversion within the aneurysm dome is feasible. This could lead to more effective and a safer IA treatment using FDs. PMID:26869741

  1. Endovascular treatment of unruptured aneurysms of cavernous and ophthalmic segment of internal carotid artery with flow diverter device Pipeline

    PubMed Central

    Mounayer, Charbel; Seruga, Tomaz

    2016-01-01

    Abstract Background Intra-arterial treatment of aneurysms by redirecting blood flow is a newer method. The redirection is based on a significantly more densely braided wire stent. The stent wall keeps the blood in the lumen of the stent and slows down the turbulent flow in the aneurysms. Stagnation of blood in the aneurysm sac leads to the formation of thrombus and subsequent exclusion of the aneurysm from the circulation. The aim of the study was to evaluate flow diverter device Pipeline for broad neck and giant aneurysm treatment. Methods Fifteen patients with discovered aneurysm of the internal carotid artery were treated between November 2010 and February 2014. The majority of aneurysms of the internal carotid artery were located intradural at the ophthalmic part of the artery. The patients were treated using a flow diverter device Pipeline, which was placed over the aneurysm neck. Treatment success was assessed clinically and angiographically using O’Kelly Marotta scale. Results Control angiography immediately after the release of the stent showed stagnation of the blood flow in the aneurysm sac. In none of the patients procedural and periprocedural complications were observed. 6 months after the procedure, control CT or MR angiography showed in almost all cases exclusion of the aneurysm from the circulation and normal blood flow in the treated artery. Neurological status six months after the procedure was normal in all patients. Conclusions Treatment of aneurysms with flow diverter Pipeline device is a safe and significantly less time consuming method in comparison with standard techniques. This new method is a promising approach in treatment of broad neck aneurysms. PMID:27904445

  2. Robotic endovascular surgery.

    PubMed

    Au, Stephanie; Ko, Koel; Tsang, Josephine; Chan, Yiu Che

    2014-01-01

    The purpose of this review is to compare conventional endovascular procedures and the robotic endovascular approach in aortic aneurysm repair. Despite advantages over open surgery, conventional endovascular surgery has limitations. To develop an alternative, efforts have been focused on robotic endovascular systems. Two of the 3 studies comparing procedure times demonstrated reduced procedure time in the robotic group, by 6 times (p < 0.05). One study demonstrated that robotic procedures reduced fluoroscopic exposure time by 12 minute (p < 0.001). Three in-vitro studies showed that the number of movements required in robotic surgery was reduced up to 10 times (p < 0.05). One of 2 studies measuring robotic performance score showed a better performance score in the robotic endovascular group (p = 0.007). These results demonstrate that the robotic technique has multiple advantages over the conventional procedure, including improved catheter stability, a shorter learning curve, reduced procedure time, and better performance in cannulating tortuous vessels. However, robotic endovascular technology may be limited by the cost of the system, the size of the catheter, and the setup time required preoperatively. Further comparative studies between conventional and robotic approaches regarding cost-effectiveness, safety, and performance in cases involving complex anatomy and fenestrated stent grafts are essential. Nevertheless, this revolutionary technology is increasingly popular and may be the next milestone in endovascular surgery.

  3. [Intraoperative monitoring of cerebral blood-flow and condition of cerebral at open and endovascular interventions in carotid system].

    PubMed

    Kuntsevich, G I; Tanashian, M M; Skrylev, S I; Krotenkova, M V; Shchipakin, V L; Koshcheev, A Iu; Lagoda, O V; Gemdzhian, E G; Medvedev, R B; Kulikova, S N

    2011-01-01

    The aim of our research is to study hemodynamic and embolic situation during the carotid endarterectomy (CEA), carotid angioplastic and stenting (CAS), and to reveal the prognostic significance of the data provided by intraoperative monitoring of the brain blood flow in exposing acute ischemic lesions in brain. Intraoperative monitoring of blood flow in artery ophthalmic vas carried out with 60% of patients, in the middle cerebral artery-with 40% during the main stages of CEA, and with 64 patients in the middle cerebral artery during CAS. The comparison of the data of intraoperative monitoring of blood flow in middle cerebral artery with the result of brain diffusion-weighted magnetic resonance imaging (DW-MRI) 24 hours after the operation shows, that solid microembolic signals and vasospasm are prognostic signals (sensibility and specifics make up 95%) in the development of acute ischemic cerebral lesions. The monitoring of blood flow in artery ophthalmic is of the greatest diagnostic value in estimation of the hemodynamic situation, but it is of the lowest practical value in detecting microembolic signals. According to the data of the intraoperative blood flow monitoring in middle cerebral artery in group CEA the development of acute ischemic cerebral lesions were predicted with 11,1% of patients and the cause of postoperative stroke, developed by 2,9% of the patients, was specified. According to the result of DW-MRI, acute ischemic cerebral lesions were diagnosed with 21% of patients, that is, 18% of ischemic cerebral lesions were asymptomatic. In group CAS ischemic cerebral lesions were prognosed with 30% of patients, actually they were later detected with 40,6% of cases by means of DW-MRI. According to the data of intraoperative of blood flow monitoring the cause of the development of postoperative stroke was specified in 6,2% of cause; in 34,4% of cause the acute ischemic cerebral lesions were asymptomatic.

  4. Accuracy of Centerline of Flow Measurement for Sizing of the Zenith AAA Endovascular Graft and Predictive Factor for Risk of Inadequate Sizing

    SciTech Connect

    Higashiura, Wataru Kichikawa, Kimihiko; Sakaguchi, Shoji; Tabayashi, Nobuoki; Taniguchi, Shigeki; Uchida, Hideo

    2009-05-15

    The purpose of this study was to evaluate the accuracy of centerline of flow (CLF) measurement for precise sizing of the Zenith AAA endovascular graft (Zenith) and to identify predictive factors of risk of inadequate endograft sizing. We analyzed 42 consecutive patients treated using the Zenith with pre- and postoperative multidetector CT between 2001 and 2007. Endograft sizing was retrospectively performed using CLF on a three-dimensional workstation. The following parameters were investigated: (a) change in distance from lowest renal artery to hypogastric artery between CLF on preoperative CT (CLFp) and CLF of graft path on postoperative CT (CLFg); (b) supposed success rate of adequate endograft length selection; and (c) predictive factors for significant alteration (>10 mm) between CLFp and CLFg. Median change in distance from lowest renal artery to hypogastric artery was 4 mm. CLFg was >10 mm shorter than CLFp in 10 of 84 limbs (12%). Multivariate analysis demonstrated tortuosity index (TI) of infrarenal abdominal aorta (p = 0.019), aneurysm diameter (p = 0.035), and ipsilateral side of the main body insertion (p = 0.042) as predictive factors of significant alteration between CLFp and CLFg. Adequate endograft length selection was achieved in 39 of 42 cases (93%). All three inadequate endograft length selections were associated with tortuous aorta (TI > 20 mm). In conclusion, distance calculations based on CLF measurement provided accurate length selection of the Zenith in the majority of cases. TI, aneurysm diameter, and ipsilateral side were predictive factors for significant alteration. The CLF and aortic measurements including the TI may allow for improved sizing for Zenith placements.

  5. Accuracy of centerline of flow measurement for sizing of the Zenith AAA endovascular graft and predictive factor for risk of inadequate sizing.

    PubMed

    Higashiura, Wataru; Kichikawa, Kimihiko; Sakaguchi, Shoji; Tabayashi, Nobuoki; Taniguchi, Shigeki; Uchida, Hideo

    2009-05-01

    The purpose of this study was to evaluate the accuracy of centerline of flow (CLF) measurement for precise sizing of the Zenith AAA endovascular graft (Zenith) and to identify predictive factors of risk of inadequate endograft sizing. We analyzed 42 consecutive patients treated using the Zenith with pre- and postoperative multidetector CT between 2001 and 2007. Endograft sizing was retrospectively performed using CLF on a three-dimensional workstation. The following parameters were investigated: (a) change in distance from lowest renal artery to hypogastric artery between CLF on preoperative CT (CLFp) and CLF of graft path on postoperative CT (CLFg); (b) supposed success rate of adequate endograft length selection; and (c) predictive factors for significant alteration (>10 mm) between CLFp and CLFg. Median change in distance from lowest renal artery to hypogastric artery was 4 mm. CLFg was >10 mm shorter than CLFp in 10 of 84 limbs (12%). Multivariate analysis demonstrated tortuosity index (TI) of infrarenal abdominal aorta (p = 0.019), aneurysm diameter (p = 0.035), and ipsilateral side of the main body insertion (p = 0.042) as predictive factors of significant alteration between CLFp and CLFg. Adequate endograft length selection was achieved in 39 of 42 cases (93%). All three inadequate endograft length selections were associated with tortuous aorta (TI > 20 mm). In conclusion, distance calculations based on CLF measurement provided accurate length selection of the Zenith in the majority of cases. TI, aneurysm diameter, and ipsilateral side were predictive factors for significant alteration. The CLF and aortic measurements including the TI may allow for improved sizing for Zenith placements.

  6. Preservation of hypogastric flow and control of iliac aneurysm size in the treatment of aortoiliac aneurysms using the Nellix EndoVascular Aneurysm Sealing endograft.

    PubMed

    Krievins, Dainis K; Savlovskis, Janis; Holden, Andrew H; Kisis, Kaspars; Hill, Andrew A; Gedins, Marcis; Ezite, Natalija; Zarins, Christopher K

    2016-11-01

    The purpose of this study was to determine the long-term effectiveness of endovascular aneurysm sealing (EVAS) in the treatment of complex aortoiliac aneurysms with preservation of hypogastric artery flow. We reviewed all patients with abdominal aortic aneurysms (AAAs) and common iliac aneurysms (CIAs) enrolled and treated in prospective studies of EVAS using the Nellix endograft (Endologix, Irvine, Calif) at two centers from 2008 to 2014. Patients with 1 year or more of computed tomography follow-up underwent quantitative morphometric assessment by two independent vascular radiologists blinded to clinical outcome results. Hypogastric patency and CIA diameter changes over time were assessed and compared in three treatment groups: totally excluded CIA, partially excluded CIA, and untreated CIA. Among 125 patients with EVAS, 68 patients (mean age, 75 ± 8 years; 79% men) had both AAA (mean diameter, 55.8 ± 2.0 mm) and CIA (median diameter, 23.4; interquartile range, 21.3-27.0 mm), with bilateral CIAs in 33 patients. Treatment of 101 CIAs included complete CIA exclusion in 40 (39.6%), partial CIA exclusion in 33 (32.7%), and no CIA treatment in 28 (27.7%), with successful AAA exclusion in all patients. Internal iliac flow was preserved in all 122 hypogastric arteries that were patent before treatment (14 hypogastric arteries were occluded at baseline). During the 5-year follow-up period (median follow-up, 24.7 months; range, 11.5-61.7 months), three patients required secondary treatment with hypogastric occlusion and graft extension to the external iliac. Thus, internal iliac flow was maintained in 98% of at-risk hypogastric arteries. There were no aneurysm-related clinical events, except for the three secondary treatments. Totally excluded iliac aneurysms did not change in diameter over time (P = .85), whereas untreated CIAs enlarged at a rate of 0.16 mm/y (95% confidence interval, 0.09-0.23; P < .0001). Partially excluded CIAs enlarged at a higher rate

  7. Modified Strongly Implicit Procedure for groundwater flow analysis

    NASA Astrophysics Data System (ADS)

    Mohan Kumar, M. S.; Sridharan, K.; Lakshmana Rao, N. S.

    1986-10-01

    A Modified Strongly Implicit Procedure (MSIP) to solve two dimensional groundwater flow problems in non-rectangular regions is presented. At present while using SIP, such problems are solved over a superscribed rectangular computational region with zero transmissivities for nodes outside the region of interest. This leads to wastage in computer storage and time. The MSIP is developed to handle non-rectangular regions directly without such dummy nodes. It is found that except for four types of boundary nodes, the same equations as in the normal SIP are applicable. The relationships for the special types of boundary nodes for row computations are presented. The method is tested on two test problems and compared with other finite difference methods, and MSIP is found to be the best. The MSIP will be particularly advantageous in regions with non-rectangular boundaries and where a number of parameters have to be stored for each node.

  8. Gene flow, invasiveness, and ecological impact of genetically modified crops.

    PubMed

    Warwick, Suzanne I; Beckie, Hugh J; Hall, Linda M

    2009-06-01

    The main environmental concerns about genetically modified (GM) crops are the potential weediness or invasiveness in the crop itself or in its wild or weedy relatives as a result of transgene movement. Here we briefly review evidence for pollen- and seed-mediated gene flow from GM crops to non-GM or other GM crops and to wild relatives. The report focuses on the effect of abiotic and biotic stress-tolerance traits on plant fitness and their potential to increase weedy or invasive tendencies. An evaluation of weediness and invasive traits that contribute to the success of agricultural weeds and invasive plants was of limited value in predicting the effect of biotic and abiotic stress-tolerance GM traits, suggesting context-specific evaluation rather than generalizations. Fitness data on herbicide, insect, and disease resistance, as well as cold-, drought-, and salinity-tolerance traits, are reviewed. We describe useful ecological models predicting the effects of gene flow and altered fitness in GM crops and wild/weedy relatives, as well as suitable mitigation measures. A better understanding of factors controlling population size, dynamics, and range limits in weedy volunteer GM crop and related host or target weed populations is necessary before the effect of biotic and abiotic stress-tolerance GM traits can be fully assessed.

  9. Endovascular Repair of Blunt Popliteal Arterial Injuries

    PubMed Central

    Zhong, Shan; Chen, Zhong; Dong, Peng; Sun, Yequan; Zhu, Wei; Pan, Xiaolin; Qi, Deming

    2016-01-01

    Objective To evaluate the feasibility and effectiveness of endovascular repair for blunt popliteal arterial injuries. Materials and Methods A retrospective analysis of seven patients with clinical suspicion of popliteal arterial injuries that were confirmed by arteriography was performed from September 2009 to July 2014. Clinical data included demographics, mechanism of injury, type of injury, location of injury, concomitant injuries, time of endovascular procedures, time interval from trauma to blood flow restoration, instrument utilized, and follow-up. All patients were male (mean age of 35.9 ± 10.3 years). The type of lesion involved intimal injury (n = 1), partial transection (n = 2), complete transection (n = 2), arteriovenous fistula (n = 1), and pseudoaneurysm (n = 1). All patients underwent endovascular repair of blunt popliteal arterial injuries. Results Technical success rate was 100%. Intimal injury was treated with a bare-metal stent. Pseudoaneurysm and popliteal artery transections were treated with bare-metal stents. Arteriovenous fistula was treated with bare-metal stent and coils. No perioperative death and procedure-related complication occurred. The average follow-up was 20.9 ± 2.3 months (range 18–24 months). One patient underwent intra-arterial thrombolysis due to stent thrombosis at 18 months after the procedure. All limbs were salvaged. Stent migration, deformation, or fracture was not found during the follow-up. Conclusion Endovascular repair seems to be a viable approach for patients with blunt popliteal arterial injuries, especially on an emergency basis. Endovascular repair may be effective in the short-term. Further studies are required to evaluate the long-term efficacy of endovascular repair. PMID:27587969

  10. Comparison of Orbiter PRCS Plume Flow Fields Using CFD and Modified Source Flow Codes

    NASA Technical Reports Server (NTRS)

    Rochelle, Wm. C.; Kinsey, Robin E.; Reid, Ethan A.; Stuart, Phillip C.; Lumpkin, Forrest E.

    1997-01-01

    The Space Shuttle Orbiter will use Reaction Control System (RCS) jets for docking with the planned International Space Station (ISS). During approach and backout maneuvers, plumes from these jets could cause high pressure, heating, and thermal loads on ISS components. The object of this paper is to present comparisons of RCS plume flow fields used to calculate these ISS environments. Because of the complexities of 3-D plumes with variable scarf-angle and multi-jet combinations, NASA/JSC developed a plume flow-field methodology for all of these Orbiter jets. The RCS Plume Model (RPM), which includes effects of scarfed nozzles and dual jets, was developed as a modified source-flow engineering tool to rapidly generate plume properties and impingement environments on ISS components. This paper presents flow-field properties from four PRCS jets: F3U low scarf-angle single jet, F3F high scarf-angle single jet, DTU zero scarf-angle dual jet, and F1F/F2F high scarf-angle dual jet. The RPM results compared well with plume flow fields using four CFD programs: General Aerodynamic Simulation Program (GASP), Cartesian (CART), Unified Solution Algorithm (USA), and Reacting and Multi-phase Program (RAMP). Good comparisons of predicted pressures are shown with STS 64 Shuttle Plume Impingement Flight Experiment (SPIFEX) data.

  11. Bacteriological testing of a modified laminar flow microbiological safety cabinet.

    PubMed

    Heidt, P J

    1982-01-01

    A modified microbiological safety cabinet which can be used as a class II and a class III safety cabinet has been bacteriologically tested. This cabinet makes use of a high-speed down-flow air curtain in the front opening to minimize the amount of air escaping over the arms of the operator. By using artificial aerosols and a dummy or a test person placing his arms into the working opening of the cabinet, a transfer from the inside to the environment was detected only when the highest concentration of the test aerosol was used. Since the number of bacteria detected was very low, this is considered to be acceptable. When the cabinet was used as a class III type, with a glove panel mounted in the front opening, leakage from the environment occurred. This could be completely prevented by fixing tape over the hinge of the front panel. The conclusion is drawn that this type of biohazard hood can be safely used as a class II and a class III microbiological safety cabinet, provided the construction of the hinge of the front panel will be adapted to prevent transfer from the environment to the working area.

  12. Numerical model of liquid metal flow in steel making tundish with flow modifiers

    NASA Astrophysics Data System (ADS)

    Vasantrao More, Manas; Saha, Sandip Kumar; Marje, Vishal; Balachandran, G.

    2017-04-01

    The optimum condition for clean steel production in the tundish of a continuous casting process reactor can be obtained using numerical modelling. Five different arrangements of flow modifier in the form of impact pad systems deployed in an eight ton, delta shaped, and two strand bloom caster tundish are analysed and optimum design of the impact pad to improve the inclusion removal efficiency is evolved. Reynolds Averaged Navier-Strokes (RANS) equations with standard k-ε model of turbulence and energy equation are used to study fluid flow and inclusion flotation in the tundish. The inclusion separation efficiency is evaluated by solving the inclusion transport equation. Height variations along with additional notch amongst different impact pads yield best micro inclusion separation efficiency.

  13. Comparative study of novel endovascular treatment techniques for intracranial aneurysms

    NASA Astrophysics Data System (ADS)

    Cantón, Gádor; Lasheras, Juan C.; Levy, David I.; Sparks, Steven R.

    2002-11-01

    Intracranial aneurysms are life-threatening vascular lesions, which are potentially treatable to avoid the consequences of their rupture. Current treatments, either surgical or endovascular, are all guided to reduce the hemodynamic forces acting on the aneurysm wall in an effort to minimize the risk of rupture. Surgical clipping is still the most used technique to treat this type of aneurysm but there is a continued demand for less invasive approaches. This has led to the development of several endovascular techniques. We report here a comparative study of the reduction in the hemodynamic stresses and the modification of the flow in the parent vessel resulting from the use of three different techniques. The first one consists of endosaccular packing with platinum coils (GDC, Target Therapeutics), which is already widely used but its long-term efficacy has not yet been determined. The second one consists of the embolization of the aneurismal sac with Onyx, a polymer which hardens when in contact with the blood (being developed by Micro Therapeutics, Inc.). The third one involves the packing of the sac with hydrocoils, platinum wires coated with a gel which quickly hydrates when in contact with blood (developed by MicroVention). A Digital Particle Image Velocimetry (DPIV) system is used to measure in vitro the velocity field inside a model of an ACOM aneurysm (an aneurysm forming in the anterior communicating artery). Physiological accurate pulsatile flow conditions are input to the arterial model through a programmable pump. The measurements show that although all treatment techniques lead to a reduction in both normal and tangential shear stresses on the aneurismal sac, each one of them also leads to different modifications of the flow in the parent vessel which may have consequences related to potential for clotting. Comparison of the untreated aneurysm with the above three treated cases also showed that the characteristics of the wall shear stresses on the parent

  14. MR-guided Passive Catheter Tracking for Endovascular Therapy

    PubMed Central

    Martin, Alastair; Lillaney, Prasheel; Losey, Aaron; Hetts, Steven W.

    2015-01-01

    Synopsis The use of MR guidance for endovascular intervention is appealing due to its lack of ionizing radiation, high-contrast visualization of vessel walls and adjacent soft tissues, multiplanar capabilities, and potential to incorporate functional information such as flow, fluid dynamics, perfusion, or cardiac motion. Concurrent advances in the design of “real-time” MR fluoroscopy pulse sequences and the development of MR compatible endovascular devices have facilitated progress from initial in vitro and animal feasibility studies of the initial use of MR guidance for endovascular interventions to human clinical applications. This review highlights current state-of-the-art imaging techniques and hardware used for passive tracking of endovascular devices in interventional MRI, including negative contrast, passive contrast, non-proton multispectral, and direct current techniques. The advantages and disadvantages of passive tracking relative to active tracking are also summarized. PMID:26499277

  15. Redo thoracic endovascular aortic repair due to endoleak with celiac artery snorkeling.

    PubMed

    Planer, David; Bliagos, Dimitrios; Gray, William A

    2011-10-01

    Reintervention due to endoleak of aortic endograft repair is often challenging. Herein, we report endovascular endoleak repair in a patient with previous thoracic and abdominal endovascular grafts with extensive coverage of the aorta. The present technique included snorkeling of the celiac trunk to preserve antegrade flow in the celiac artery and to maintain future options for reintervention.

  16. Endovascular vs medical management of acute ischemic stroke.

    PubMed

    Chen, Ching-Jen; Ding, Dale; Starke, Robert M; Mehndiratta, Prachi; Crowley, R Webster; Liu, Kenneth C; Southerland, Andrew M; Worrall, Bradford B

    2015-12-01

    To compare the outcomes between endovascular and medical management of acute ischemic stroke in recent randomized controlled trials (RCT). A systematic literature review was performed, and multicenter, prospective RCTs published from January 1, 2013, to May 1, 2015, directly comparing endovascular therapy to medical management for patients with acute ischemic stroke were included. Meta-analyses of modified Rankin Scale (mRS) and mortality at 90 days and symptomatic intracranial hemorrhage (sICH) for endovascular therapy and medical management were performed. Eight multicenter, prospective RCTs (Interventional Management of Stroke [IMS] III, Local Versus Systemic Thrombolysis for Acute Ischemic Stroke [SYNTHESIS] Expansion, Mechanical Retrieval and Recanalization of Stroke Clots Using Embolectomy [MR RESCUE], Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands [MR CLEAN], Evaluation Study of Congestive Heart Failure and Pulmonary Artery Catheterization Effectiveness [ESCAPE], Extending the Time for Thrombolysis in Emergency Neurological Deficits-Intra-Arterial [EXTEND-IA], Solitaire With the Intention For Thrombectomy as Primary Endovascular Treatment [SWIFT PRIME], and Endovascular Revascularization With Solitaire Device Versus Best Medical Therapy in Anterior Circulation Stroke Within 8 Hours [REVASCAT]) comprising 2,423 patients were included. Meta-analysis of pooled data demonstrated functional independence (mRS 0-2) at 90 days in favor of endovascular therapy (odds ratio [OR] = 1.71; p = 0.005). Subgroup analysis of the 6 trials with large vessel occlusion (LVO) criteria also demonstrated functional independence at 90 days in favor of endovascular therapy (OR = 2.23; p < 0.00001). Subgroup analysis of the 5 trials that primarily utilized stent retriever devices (≥70%) in the intervention arm demonstrated functional independence at 90 days in favor of endovascular therapy (OR = 2.39; p < 0.00001). No

  17. Endovascular vs medical management of acute ischemic stroke

    PubMed Central

    Ding, Dale; Starke, Robert M.; Mehndiratta, Prachi; Crowley, R. Webster; Liu, Kenneth C.; Southerland, Andrew M.; Worrall, Bradford B.

    2015-01-01

    Objective: To compare the outcomes between endovascular and medical management of acute ischemic stroke in recent randomized controlled trials (RCT). Methods: A systematic literature review was performed, and multicenter, prospective RCTs published from January 1, 2013, to May 1, 2015, directly comparing endovascular therapy to medical management for patients with acute ischemic stroke were included. Meta-analyses of modified Rankin Scale (mRS) and mortality at 90 days and symptomatic intracranial hemorrhage (sICH) for endovascular therapy and medical management were performed. Results: Eight multicenter, prospective RCTs (Interventional Management of Stroke [IMS] III, Local Versus Systemic Thrombolysis for Acute Ischemic Stroke [SYNTHESIS] Expansion, Mechanical Retrieval and Recanalization of Stroke Clots Using Embolectomy [MR RESCUE], Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands [MR CLEAN], Evaluation Study of Congestive Heart Failure and Pulmonary Artery Catheterization Effectiveness [ESCAPE], Extending the Time for Thrombolysis in Emergency Neurological Deficits–Intra-Arterial [EXTEND-IA], Solitaire With the Intention For Thrombectomy as Primary Endovascular Treatment [SWIFT PRIME], and Endovascular Revascularization With Solitaire Device Versus Best Medical Therapy in Anterior Circulation Stroke Within 8 Hours [REVASCAT]) comprising 2,423 patients were included. Meta-analysis of pooled data demonstrated functional independence (mRS 0–2) at 90 days in favor of endovascular therapy (odds ratio [OR] = 1.71; p = 0.005). Subgroup analysis of the 6 trials with large vessel occlusion (LVO) criteria also demonstrated functional independence at 90 days in favor of endovascular therapy (OR = 2.23; p < 0.00001). Subgroup analysis of the 5 trials that primarily utilized stent retriever devices (≥70%) in the intervention arm demonstrated functional independence at 90 days in favor of endovascular therapy

  18. Modified gravity and large scale flows, a review

    NASA Astrophysics Data System (ADS)

    Mould, Jeremy

    2017-02-01

    Large scale flows have been a challenging feature of cosmography ever since galaxy scaling relations came on the scene 40 years ago. The next generation of surveys will offer a serious test of the standard cosmology.

  19. Effect of non-Maxwellian electrons on shear flow modified ion acoustic solitons

    NASA Astrophysics Data System (ADS)

    Shafiq, Ammara; Ali Shan, S.; Saleem, H.

    2017-04-01

    Dynamics of shear flow modified ion acoustic wave is investigated assuming electrons to follow q-nonextensive and Cairns distribution functions. A modified linear dispersion relation and electrostatic KdV solitons are analyzed. Results are illustrated considering solar wind and F-region ionospheric plasmas. Effects of non-Maxwellian distribution of electrons on the amplitude and the width of solitons are pointed out in the presence of field-aligned inhomogeneous flow.

  20. Endovascular extraction techniques

    PubMed Central

    Bracke, F.A.; Meijer, A.; van Gelder, B.

    2001-01-01

    The use of lead extraction is expanding with the introduction of new endovascular extraction techniques. Indications for extraction of chronically implanted pacemaker leads have been classified as mandatory, necessary or discretionary, but their rationale is often based on clinical judgement without corresponding support from the literature. We reviewed the literature of pacemaker lead-related complications as a starting point for discussing the indications for lead extraction. ImagesFigure 1Figure 2Figure 3 PMID:25696699

  1. Rat Endovascular Perforation Model

    PubMed Central

    Sehba, Fatima A.

    2014-01-01

    Experimental animal models of aneurysmal subarachnoid hemorrhage (SAH) have provided a wealth of information on the mechanisms of brain injury. The Rat endovascular perforation model (EVP) replicates the early pathophysiology of SAH and hence is frequently used to study early brain injury following SAH. This paper presents a brief review of historical development of the EVP model, details the technique used to create SAH and considerations necessary to overcome technical challenges. PMID:25213427

  2. [Endovascular surgery in the war].

    PubMed

    Reva, V A; Samokhvalov, I M

    2015-01-01

    Rapid growth of medical technologies has led to implementation of endovascular methods of diagnosis and treatment into rapidly developing battlefield surgery. This work based on analysing all available current publications generalizes the data on using endovascular surgery in combat vascular injury. During the Korean war (1950-1953) American surgeons for the first time performed endovascular balloon occlusion of the aorta - the first intravascular intervention carried out in a zone of combat operations. Half a century thereafter, with the beginning of the war in Afghanistan (2001) and in Iraq (2003) surgeons of central hospitals of the USA Armed Forces began performing delayed endovascular operations to the wounded. The development of technologies, advent of mobile angiographs made it possible to later on implement high-tech endovascular interventions in a zone of combat operations. At first, more often they performed implantation of cava filters, somewhat afterward - angioembolization of damaged accessory vessels, stenting and endovascular repair of major arteries. The first in the theatre of war endovascular prosthetic repair of the thoracic aorta for severe closed injury was performed in 2008. Russian experience of using endovascular surgery in combat injuries is limited to diagnostic angiography and regional intraarterial perfusion. Despite the advent of stationary angiographs in large hospitals of the RF Ministry of Defence in the early 1990s, endovascular operations for combat vascular injury are casuistic. Foreign experience in active implementation of endovascular technologies to treatment of war-time injuries has substantiated feasibility of using intravascular interventions in tertiary care military hospitals. Carrying out basic training courses on endovascular surgery should become an organic part of preparing multimodality general battlefield surgeons rendering care on the theatre of combat operations.

  3. Flow splitting modifies the helical motion in submarine channels

    NASA Astrophysics Data System (ADS)

    Islam, M. Ashraful; Imran, Jasim; Pirmez, Carlos; Cantelli, Alessandro

    2008-11-01

    Intricately meandering channels of various scales constitute a major morphological feature of the submarine slope and fan systems. These channels act as conduits of density-driven gravity underflows and in turn are shaped by these underflows. The relationship between channel curvature and the dynamics of sediment-laden underflows commonly known as turbidity current has been an enigma, and recently, a subject of controversy. This contribution unravels the flow field of turbidity current at submarine channel bends captured from large scale laboratory experiments. The experimental results show that a mildly sloping channel bank greatly enhances the tilt of the turbidity current-ambient water interface, so much so that the current completely separates from the convex or the inside bank. We also show that irrespective of the shape of the channel cross section, two cells of helical flow appear in confined submarine bend flow. The near-bed cell has a circulation pattern similar to that observed in fluvial channels; the other cell has an opposite sense of rotation. If, on the other hand, a portion of the flow detaches from the body of the current and spills to the concave or outside overbank area, the upper circulation cell becomes suppressed by the resulting lateral convection.

  4. High flow rates during modified ultrafiltration decrease cerebral blood flow velocity and venous oxygen saturation in infants.

    PubMed

    Rodriguez, Rosendo A; Ruel, Marc; Broecker, Lothar; Cornel, Garry

    2005-07-01

    The intracranial hemodynamic effects of modified ultrafiltration in children are unknown. We investigated the effects of different blood flow rates during modified ultrafiltration on the cerebral hemodynamics of children with weights above and below 10 kg. Thirty-one children (weights: < or = 10 kg, n = 21; > 10 kg, n = 10) undergoing cardiopulmonary bypass were studied. Middle-cerebral artery blood flow velocities and cerebral mixed venous oxygen saturations were measured before, five minutes from the beginning, and at the end of ultrafiltration. Patients were classified according to their blood flow rates during ultrafiltration in three groups: high (> or = 20 mL/kg/min), moderate (10-19 mL/kg/min), and low flow rates (< 10 mL/kg/min). During modified ultrafiltration, blood pressures and hematocrit increased (p < 0.001), but cerebral blood flow velocities and mixed venous oxygen saturations decreased (p < 0.001). A significant correlation was found between blood flow rates of ultrafiltration and the decline in mean cerebral blood flow velocity (r = - 0.48; p = 0.005) and cerebral oxygen saturation (r = - 0.49; p = 0.005) or hematocrit increase (r = 0.59; p = 0.001). Infants exposed to high flow rates had greater reduction of cerebral blood flow velocity and regional mixed venous saturation and higher hematocrit at the end of ultrafiltration compared with those subjected to moderate and low flow rates (p < 0.04). No significant difference was found between moderate and low flow groups. The flow rate of ultrafiltration was the only independent predictor of the changes in cerebral mixed venous oxygen saturation (p = 0.033). High blood flow rates through the ultrafilter during modified ultrafiltration transiently decrease the cerebral circulation in young infants compared with lower blood flow rates. These effects may be related to an increased diastolic runoff from the aorta into the ultrafiltration circuit that leads to a "stealing" effect from the intracranial

  5. Contemporary management of carotid blowout syndrome utilizing endovascular techniques.

    PubMed

    Manzoor, Nauman F; Rezaee, Rod P; Ray, Abhishek; Wick, Cameron C; Blackham, Kristine; Stepnick, David; Lavertu, Pierre; Zender, Chad A

    2017-02-01

    To illustrate complex interdisciplinary decision making and the utility of modern endovascular techniques in the management of patients with carotid blowout syndrome (CBS). Retrospective chart review. Patients treated with endovascular strategies and/or surgical modalities were included. Control of hemorrhage, neurological, and survival outcomes were studied. Between 2004 and 2014, 33 patients had 38 hemorrhagic events related to head and neck cancer that were managed with endovascular means. Of these, 23 were localized to the external carotid artery (ECA) branches and five localized to the ECA main trunk; nine were related to the common carotid artery (CCA) or internal carotid artery (ICA), and one event was related to the innominate artery. Seven events related to the CCA/ICA or innominate artery were managed with endovascular sacrifice, whereas three cases were managed with a flow-preserving approach (covered stent). Only one patient developed permanent hemiparesis. In two of the three cases where the flow-preserving approach was used, the covered stent eventually became exposed via the overlying soft tissue defect, and definitive management using carotid revascularization or resection was employed to prevent further hemorrhage. In cases of soft tissue necrosis, vascularized tissues were used to cover the great vessels as applicable. The use of modern endovascular approaches for management of acute CBS yields optimal results and should be employed in a coordinated manner by the head and neck surgeon and the neurointerventionalist. 4. Laryngoscope, 2016 127:383-390, 2017. © 2016 The American Laryngological, Rhinological and Otological Society, Inc.

  6. TOPICAL REVIEW: Endovascular interventional magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Bartels, L. W.; Bakker, C. J. G.

    2003-07-01

    Minimally invasive interventional radiological procedures, such as balloon angioplasty, stent placement or coiling of aneurysms, play an increasingly important role in the treatment of patients suffering from vascular disease. The non-destructive nature of magnetic resonance imaging (MRI), its ability to combine the acquisition of high quality anatomical images and functional information, such as blood flow velocities, perfusion and diffusion, together with its inherent three dimensionality and tomographic imaging capacities, have been advocated as advantages of using the MRI technique for guidance of endovascular radiological interventions. Within this light, endovascular interventional MRI has emerged as an interesting and promising new branch of interventional radiology. In this review article, the authors will give an overview of the most important issues related to this field. In this context, we will focus on the prerequisites for endovascular interventional MRI to come to maturity. In particular, the various approaches for device tracking that were proposed will be discussed and categorized. Furthermore, dedicated MRI systems, safety and compatibility issues and promising applications that could become clinical practice in the future will be discussed.

  7. Effect of reference conditions on flow rate, modifier fraction and retention in supercritical fluid chromatography.

    PubMed

    De Pauw, Ruben; Shoykhet Choikhet, Konstantin; Desmet, Gert; Broeckhoven, Ken

    2016-08-12

    When using compressible mobile phases such as fluidic CO2, the density, the volumetric flow rates and volumetric fractions are pressure dependent. The pressure and temperature definition of these volumetric parameters (referred to as the reference conditions) may alter between systems, manufacturers and operating conditions. A supercritical fluid chromatography system was modified to operate in two modes with different definition of the eluent delivery parameters, referred to as fixed and variable mode. For the variable mode, the volumetric parameters are defined with reference to the pump operating pressure and actual pump head temperature. These conditions may vary when, e.g. changing the column length, permeability, flow rate, etc. and are thus variable reference conditions. For the fixed mode, the reference conditions were set at 150bar and 30°C, resulting in a mass flow rate and mass fraction of modifier definition which is independent of the operation conditions. For the variable mode, the mass flow rate of carbon dioxide increases with system pump operating pressure, decreasing the fraction of modifier. Comparing the void times and retention factor shows that the deviation between the two modes is almost independent of modifier percentage, but depends on the operating pressure. Recalculating the set volumetric fraction of modifier to the mass fraction results in the same retention behaviour for both modes. This shows that retention in SFC can be best modelled using the mass fraction of modifier. The fixed mode also simplifies method scaling as it only requires matching average column pressure.

  8. Combined Endovascular and Microsurgical Management of Complex Cerebral Aneurysms

    PubMed Central

    Choudhri, Omar; Mukerji, Nitin; Steinberg, Gary K.

    2013-01-01

    Cerebral aneurysms are associated with a 50% mortality rate after rupture and patients can suffer significant morbidity during subsequent treatment. Neurosurgical management of both ruptured and unruptured aneurysms has evolved over the years. The historical practice of using microsurgical clipping to treat aneurysms has benefited in the last two decades from tremendous improvement in endovascular technology. Microsurgery and endovascular therapies are often viewed as competing treatments but it is important to recognize their individual limitations. Some aneurysms are considered complex, due to several factors such as aneurysm anatomy and a patient’s clinical condition. A complex aneurysm often cannot be completely excluded with a single approach and its successful treatment requires a combination of microsurgical and endovascular techniques. Planning such an approach relies on understanding aneurysm anatomy and thus should routinely include 3D angiographic imaging. In patients with ruptured aneurysms, endovascular coiling is a well-tolerated early treatment and residual aneurysms can be treated with intervals of definitive clipping. Microsurgical clipping also can be used to reconstruct the neck of a complex aneurysm, allowing successful placement of coils across a narrow neck. Endovascular techniques are assisted by balloons, which can be used in coiling and testing parent vessel occlusion before sacrifice. In some cases microsurgical bypasses can provide alternate flow for planned vessel sacrifice. We present current paradigms for combining endovascular and microsurgical approaches to treat complex aneurysms and share our experience in 67 such cases. A dual microsurgical–endovascular approach addresses the challenge of intracranial aneurysms. This combination can be performed safely and produces excellent rates of aneurysm obliteration. Hybrid angiographic operating-room suites can foster seamless and efficient complementary application of these two

  9. Content Validation and Evaluation of an Endovascular Teamwork Assessment Tool.

    PubMed

    Hull, L; Bicknell, C; Patel, K; Vyas, R; Van Herzeele, I; Sevdalis, N; Rudarakanchana, N

    2016-07-01

    To modify, content validate, and evaluate a teamwork assessment tool for use in endovascular surgery. A multistage, multimethod study was conducted. Stage 1 included expert review and modification of the existing Observational Teamwork Assessment for Surgery (OTAS) tool. Stage 2 included identification of additional exemplar behaviours contributing to effective teamwork and enhanced patient safety in endovascular surgery (using real-time observation, focus groups, and semistructured interviews of multidisciplinary teams). Stage 3 included content validation of exemplar behaviours using expert consensus according to established psychometric recommendations and evaluation of structure, content, feasibility, and usability of the Endovascular Observational Teamwork Assessment Tool (Endo-OTAS) by an expert multidisciplinary panel. Stage 4 included final team expert review of exemplars. OTAS core team behaviours were maintained (communication, coordination, cooperation, leadership team monitoring). Of the 114 OTAS behavioural exemplars, 19 were modified, four removed, and 39 additional endovascular-specific behaviours identified. Content validation of these 153 exemplar behaviours showed that 113/153 (73.9%) reached the predetermined Item-Content Validity Index rating for teamwork and/or patient safety. After expert team review, 140/153 (91.5%) exemplars were deemed to warrant inclusion in the tool. More than 90% of the expert panel agreed that Endo-OTAS is an appropriate teamwork assessment tool with observable behaviours. Some concerns were noted about the time required to conduct observations and provide performance feedback. Endo-OTAS is a novel teamwork assessment tool, with evidence for content validity and relevance to endovascular teams. Endo-OTAS enables systematic objective assessment of the quality of team performance during endovascular procedures. Copyright © 2016. Published by Elsevier Ltd.

  10. Modeling flow for modified concentric cylinder rheometer geometry

    NASA Astrophysics Data System (ADS)

    Ekeruche, Karen; Connelly, Kelly; Kavehpour, H. Pirouz

    2016-11-01

    Rheology experiments on biological fluids can be difficult when samples are limited in volume, sensitive to degradation, and delicate to extract from tissues. A probe-like geometry has been developed to perform shear creep experiments on biological fluids and to use the creep response to characterize fluid material properties. This probe geometry is a modified concentric cylinder setup, where the gap is large and we assume the inner cylinder rotates in an infinite fluid. To validate this assumption we perform shear creep tests with the designed probe on Newtonian and non-Newtonian fluids and vary the outer cylinder container diameter. We have also created a numerical model based on the probe geometry setup to compare with experimental results at different outer cylinder diameters. A creep test is modeled by applying rotation to the inner cylinder and solving for the deformation of the fluid throughout the gap. Steady state viscosity values are calculated from creep compliance curves and compared between experimental and numerical results.

  11. A method of calibrating wind velocity sensors with a modified gas flow calibrator

    NASA Technical Reports Server (NTRS)

    Stump, H. P.

    1978-01-01

    A procedure was described for calibrating air velocity sensors in the exhaust flow of a gas flow calibrator. The average velocity in the test section located at the calibrator exhaust was verified from the mass flow rate accurately measured by the calibrator's precision sonic nozzles. Air at elevated pressures flowed through a series of screens, diameter changes, and flow straighteners, resulting in a smooth flow through the open test section. The modified system generated air velocities of 2 to 90 meters per second with an uncertainty of about two percent for speeds below 15 meters per second and four percent for the higher speeds. Wind tunnel data correlated well with that taken in the flow calibrator.

  12. Percutaneous and Endovascular Embolization of Ruptured Hepatic Artery Aneurysm

    SciTech Connect

    Little, Andrew F.; Lee, Wai Kit

    2002-06-15

    A 72-year-old woman presented with an intraperitoneal hemorrhage from a ruptured intrahepatic arteryaneurysm, with an associated pseudoaneurysm developing a high-flow arteriovenous fistula. Persistent coagulopathy and a median arcuate ligament stenosis of the celiac axis further complicated endovascular management. Aneurysm thrombosis required percutaneous embolization with coils, a removable core guidewire and polyvinyl alcohol particles.

  13. Selection of Endovascular Approach of Vein of Galen Aneurysmal Malformation

    PubMed Central

    Ito, O.; Goto, K.; Ogata, N.; Utsunomiya, H.; Sato, S.; Fukumura, A.

    2001-01-01

    Summary Vein of Galen aneurysmal malformation (VGAM) is one of the most difficult intracranial vascular lesions because this disease consists of extremely high flow shunts and affects infants and small children. Thanks to the development of various diagnostic modalities, early diagnosis became possible allowing us to prepare appropriately according to the patients' general and neurological conditions. Recent improvements of endovascular techniques and materials enabled both transarterial and transvenous approaches even to the newborn infants, widening therapeutic windows. In this article, we discuss the selection of endovascular approaches based upon angioarchitecture of VGAM presenting four representative cases from our file. PMID:20663400

  14. Modeling Endovascular Coils as Heterogeneous Porous Media

    NASA Astrophysics Data System (ADS)

    Yadollahi Farsani, H.; Herrmann, M.; Chong, B.; Frakes, D.

    2016-12-01

    Minimally invasive surgeries are the stat-of-the-art treatments for many pathologies. Treating brain aneurysms is no exception; invasive neurovascular clipping is no longer the only option and endovascular coiling has introduced itself as the most common treatment. Coiling isolates the aneurysm from blood circulation by promoting thrombosis within the aneurysm. One approach to studying intra-aneurysmal hemodynamics consists of virtually deploying finite element coil models and then performing computational fluid dynamics. However, this approach is often computationally expensive and requires extensive resources to perform. The porous medium approach has been considered as an alternative to the conventional coil modeling approach because it lessens the complexities of computational fluid dynamics simulations by reducing the number of mesh elements needed to discretize the domain. There have been a limited number of attempts at treating the endovascular coils as homogeneous porous media. However, the heterogeneity associated with coil configurations requires a more accurately defined porous medium in which the porosity and permeability change throughout the domain. We implemented this approach by introducing a lattice of sample volumes and utilizing techniques available in the field of interactive computer graphics. We observed that the introduction of the heterogeneity assumption was associated with significant changes in simulated aneurysmal flow velocities as compared to the homogeneous assumption case. Moreover, as the sample volume size was decreased, the flow velocities approached an asymptotical value, showing the importance of the sample volume size selection. These results demonstrate that the homogeneous assumption for porous media that are inherently heterogeneous can lead to considerable errors. Additionally, this modeling approach allowed us to simulate post-treatment flows without considering the explicit geometry of a deployed endovascular coil mass

  15. Endovascular Interventions for Acute Ischemic Stroke: A Review of Recent Trials.

    PubMed

    Bishop, Bryan M

    2016-03-01

    To review recent endovascular intervention trials for acute ischemic stroke. Recent, randomized controlled trials of endovascular interventions for acute ischemic stroke were identified. The search terms "endovascular" AND "stroke" were used and filter for "randomized controlled trial" was applied; the period searched was January 1, 2013, to October 31, 2015. Randomized controlled trials of endovascular interventions in acute ischemic stroke published within the past 3 years (2013-2015). A total of 8 trials are reviewed: 3 trials published in 2013 demonstrated neutral results for endovascular interventions, and 5 trials published in 2015 demonstrated positive results for endovascular interventions. Potential reasons for the change in outcomes include better patient selection and improvement indevice technology. Patient selection improvements included selecting patients with salvageable brain tissue with an identifiable thrombus on perfusion imaging. The major improvement in device technology was the introduction of the Solitaire Flow Restoration stent retriever and the Trevo stent retriever, both of which have improved recanalization rates compared with earlier devices. Adjunctive medication considerations include the mode of sedation (general or conscious), intraprocedural anticoagulation with heparin, and intra-arterial tissue plasminogen activator. The use of endovascular devices for treating acute ischemic stroke is likely to increase as more centers become capable of integrating them into their stroke programs. It is important for pharmacists to understand the trials that evaluated endovascular interventions because differences exist with respect to device, adjunctive medication, and patient selection, all of which affect patient outcomes. © The Author(s) 2015.

  16. [Endovascular treatment of giant intracranial aneurysms].

    PubMed

    Bracard, S; Derelle, A L; Tonnelet, R; Barbier, C; Proust, F; Anxionnat, R

    2016-02-01

    Giant aneurysms are defined as having a maximal diameter higher than 25mm. The dynamic aspect of giant aneurysms, in particular, is its growth, which was responsible for parenchyma sequellae either due to haemorrhagic complications or a compression of cranial nerves. The treatment of these giant aneurysms was challenging because of its size, the mass effect and the neck diameter. These morphologic conditions required complex endovascular procedures such as remodelling, stenting, using flow diverters. Subsequently, the complex procedures increased the risk of morbidity because of ischemic complications. Despite these procedures, the risk of recurrence was high.

  17. Simulation of Couette flow using conventional Burnett equations with modified slip boundary conditions

    NASA Astrophysics Data System (ADS)

    Liu, Hualin; Zhao, Wenwen; Chen, Weifang

    2016-11-01

    Gas or liquid flow through small channels has become more and more popular due to the micro-electro-mechanical systems (MEMS) fabrication technologies such as micro-motors, electrostatic comb-drive, micro-chromatographs, micro-actuators, micro-turbines and micro-pumps, etc. The flow conditions in and around these systems are always recognized as typical transitional regimes. Under these conditions, the mean free path of gas molecules approaches the characteristic scale of the micro-devices itself, and due to the little collisions the heat and momentum cannot equilibrate between the wall and fluids quickly. Couette flow is a simple and critical model in fluid dynamics which focuses on the mechanism of the heat transfer in shear-driven micro-cavities or micro-channels. Despite numerous work on the numerical solutions of the Couette flow, how to propose stable and accurate slip boundary conditions in rarefied flow conditions still remains to be elucidated. In this paper, converged solutions for steady-state micro Couette flows are obtained by using conventional Burnett equations with a set of modified slip boundary conditions. Instead of using the physical variables at the wall, the modified slip conditions use the variables at the edge of the Knudsen layer based on a physically plausible assumption in literature that Knudsen layer has a thickness only in the order of a mean free path and molecules are likely to travel without collision in this layer. Numerical results for non-dimensional wall shear stress and heat flux are compared with those of the DSMC solutions. Although there are not much improvement in the accuracy by using this modified slip conditions, the modified conditions perform much better than the unmodified slip conditions for numerical stabilization. All results show that the set of conventional Burnett equations with second order modified conditions are proved to be an appropriate model for the micro-Couette flows.

  18. On the correspondence between polymer-modified turbulence states and transitional states in Newtonian flows

    NASA Astrophysics Data System (ADS)

    Dubief, Yves; White, Christopher

    2010-11-01

    Polymer addition is known to reduce drag in wall-bounded flows up to an asymptotic state called maximum drag reduction (MDR). The definition of MDR is still largely empirical and its uniqueness is a matter of debate. Using direct numerical simulations, a correspondence is first established between MDR and a specific state of transition in boundary layer flow. A model is derived as a function of the flow topology of the transitional Newtonian flow and the FENE-P model. The model is then extended to natural convection where heat transfer reduction (HTR) and augmentation (HTA) are observed as a function of polymer length. Yet, HTR and HTA are topologically equivalent and again correspond to a transitional state of Rayleigh Benard convection flow. This suggests that polymer-modified turbulence may be predictable as a function of the polymer solution's properties and transitional states of the corresponding Newtonian flow.

  19. 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 ...

  20. A model to simulate the haemodynamic effects of right heart pulsatile flow after modified Fontan procedure.

    PubMed Central

    Tamaki, S; Kawazoe, K; Yagihara, T; Abe, T

    1992-01-01

    The effect of pulsatile pulmonary flow after the modified Fontan procedure was examined in a model that simulated the right heart. An inlet overflow tank (preload), axial pulsatile pump, Wind-Kessel model (afterload), and an outlet overflow tank were connected in series. The standard conditions were flow 2.00 l/min with 12 mm Hg preload pressure, 3.0 Wood units resistance, and an outlet overflow tank pressure at 6 mm Hg. The pump rate was set at 80 beats/min. The simulated pulmonary arterial pressure and pulmonary flow waves produced by this model closely resembled those obtained from patients who had undergone the modified Fontan procedure. All variables except the preload were fixed and changes in pulmonary flow were examined at preload pressures of 8, 12, 15, and 17 mm Hg. As the peak pulmonary arterial pressure increased so did pulmonary flow, until it was greater than during the non-pulsatile state. Because the afterload of this model was fixed, this result suggests that there was a concomitant decrease in resistance. This model indicates that pulsatile pulmonary blood flow is likely to have a beneficial effect on the pulmonary circulation after the modified Fontan procedure. PMID:1540439

  1. Modified ion-acoustic solitary waves in plasmas with field-aligned shear flows

    SciTech Connect

    Saleem, H.; Haque, Q.

    2015-08-15

    The nonlinear dynamics of ion-acoustic waves is investigated in a plasma having field-aligned shear flow. A Korteweg-deVries-type nonlinear equation for a modified ion-acoustic wave is obtained which admits a single pulse soliton solution. The theoretical result has been applied to solar wind plasma at 1 AU for illustration.

  2. Endovascular management of pediatric aneurysms.

    PubMed

    Saleh, E; Dawson, R C

    2011-10-31

    Although the general principles of endovascular aneurysm treatment in adults hold true in children, these young patients pose unique challenges: small anatomy, longer life expectancy, associated conditions and morphological characteristics of the aneurysms. Few publications in the literature address the role of endovascular treatment for pediatric aneurysms; including series by Agid et al. (2005) (1) revisiting the Toronto series, Lasjaunias et al. (2005) (2) updating the Bicêtre series and Sanai et al (2006) (8) presenting the San Francisco series. In their conclusions, the authors of the former two publications favored endovascular treatment over microsurgery. On the other hand, the authors of the latter publication favored microsurgery over endovascular treatment. The authors reviewed Louisiana State University experience regarding endovascular treatment of pediatric aneurysms focusing on outcomes. A retrospective chart review was performed of children under 18, who underwent endovascular treatment for intracranial aneurysms between 2000 and 2009 in our institution. Twelve patients harboring seventeen aneurysms were identified. The patients ranged in age from seventeen months to seventeen years. Complete aneurysm obliteration following endovascular treatment was around 95%. Our results showed unique features for pediatric aneurysms when compared to adult aneurysms. No intra operative mortality was recorded. One aneurysm recurred (5% recurrence rate among total number of aneurysms). In this case, six months after treatment, a control angiogram showed that the coils were displaced toward the dome of the aneurysm. This recurrence occurred before the introduction of the hydro coils. One patient died during the post intervention period (8% occurrence rate among total number of patients). Outcomes were better in anterior circulation aneurysms than in posterior circulation lesions. We had no mortality, morbidity or disability in the anterior circulation aneurysm group

  3. Non-contrast-enhanced MR hepatic arteriography with time-spatial labeling inversion pulses: comparison of imaging with flow-in and modified flow-out methods.

    PubMed

    Isoda, Hiroyoshi; Furuta, Akihiro; Ohno, Tsuyoshi; Togashi, Kaori

    2017-07-01

    Background In non-contrast-enhanced magnetic resonance (MR) arteriography, the flow-out method using a selective tagging pulse with a long inversion time (TI) and a non-selective inversion recovery pulse with a short TI (the modified flow-out method) might further contribute to the suppression of background signal and facilitate improved visualization of the hepatic artery. However, no report has focused on the image quality of non-contrast-enhanced MR arteriography using the modified flow-out method. Purpose To compare the flow-in method with the modified flow-out method and to determine which method better visualizes the hepatic artery. Material and Methods Twenty-seven healthy volunteers were examined using respiratory-triggered three-dimensional true steady-state free-precession MR with two selective inversion recovery pulses (the flow-in method) or with one tagging pulse and one non-selective inversion recovery pulse (the modified flow-out method). Results Artery-to-liver contrast was significantly increased in the modified flow-out method relative to the flow-in method ( P < 0.05). In all analyses of vessel visibility, non-contrast-enhanced MR arteriography using the modified flow-out method exhibited higher scores than with the flow-in method. With respect to overall image quality, the modified flow-out method was significantly better than the flow-in method ( P < 0.01). Conclusion The modified flow-out method for non-contrast-enhanced MR angiography is a promising technique for visualizing the hepatic artery.

  4. Modified finite-element model for application to terrain-induced mesoscale flows

    SciTech Connect

    Lee, R.L.; Leone, J.M. Jr.; Gresho, P.M.

    1982-11-01

    Terrain-induced mesoscale flows are localized atmospheric motions generated primarily by surface inhomogeneities such as differential heating and irregular terrain. Well-known examples of such flows are sea-and-land breeze circulations, mountain-valley flows, urban heat island circulations and mountain lee waves. A numerical model capable of capturing the details of these frequently complicated flow patterns must often contain a realistic and rather accurate representation of the relevant terrain. Over the last decade, mesoscale models have been developed in which various approaches were used to incorporate variable terrain. In this study, a somewhat unique approach, based on a modified finite element procedure, was used to solve the nonhydrostatic planetary boundary layer equations. The nonhydrostatic and finite element features of the model are particularly advantageous for modeling flows over complex topography. The numerical aspects of the model, the parameterizations currently used, and a few preliminary results are presented.

  5. A modified stopped-flow apparatus for time-resolved protein phosphorescence

    NASA Astrophysics Data System (ADS)

    Strambini, Giovanni B.; Puntoni, Alessandro; Gonnelli, Margherita

    1997-12-01

    A type of commercial apparatus was modified and integrated in order to implement the detection of time-resolved protein phosphorescence in the stopped-flow technique. Laser excitation, photomultiplier protection from the intense fluorescence pulse, fluorescence integration, and data acquisition are all synchronized by a trigger module that takes over standard computer control of the stopped-flow apparatus. A detailed protocol is given for effective deoxygenation of the sample and flow lines and for avoiding contamination of the solutions by quenching impurities. The performance of the apparatus was tested by comparing the phosphorescence decay kinetics of the protein horse liver alcohol dehydrogenase in the stopped-flow apparatus and in a standard phosphorimeter. The time resolution of phosphorescence detection in the stopped-flow apparatus is 10 ms and the sensitivity in terms of chromophores concentration is about 0.1 μM.

  6. Endovascular Treatment of Ruptured Pericallosal Artery Aneurysms

    PubMed Central

    Ko, Jun Kyeung; Kim, Hwan Soo; Choi, Hyuk Jin; Lee, Tae Hong; Yun, Eun Young

    2015-01-01

    Objective Aneurysms arising from the pericallosal artery (PA) are uncommon and challenging to treat. The aim of this study was to report our experiences of the endovascular treatment of ruptured PA aneurysms. Methods From September 2003 to December 2013, 30 ruptured PA aneurysms in 30 patients were treated at our institution via an endovascular approach. Procedural data, clinical and angiographic results were retrospectively reviewed. Results Regarding immediate angiographic control, complete occlusion was achieved in 21 (70.0%) patients and near-complete occlusion in 9 (30.0%). Eight procedure-related complications occurred, including intraprocedural rupture and early rebleeding in three each, and thromboembolic event in two. At last follow-up, 18 patients were independent with a modified Rankin Scale (mRS) score of 0-2, and the other 12 were either dependent or had expired (mRS score, 3-6). Adjacent hematoma was found to be associated with an increased risk of poor clinical outcome. Seventeen of 23 surviving patients underwent follow-up conventional angiography (mean, 16.5 months). Results showed stable occlusion in 14 (82.4%), minor recanalization in two (11.8%), and major recanalization, which required recoiling, in one (5.9%). Conclusion Our experiences demonstrate that endovascular treatment for a ruptured PA aneurysms is both feasible and effective. However, periprocedural rebleedings were found to occur far more often (20.0%) than is generally suspected and to be associated with preoperative contrast retention. Analysis showed existing adjacent hematoma is predictive of a poor clinical outcome. PMID:26539261

  7. A modified homogeneous relaxation model for CO2 two-phase flow in vapour ejector

    NASA Astrophysics Data System (ADS)

    Haida, M.; Palacz, M.; Smolka, J.; Nowak, A. J.; Hafner, A.; Banasiak, K.

    2016-09-01

    In this study, the homogenous relaxation model (HRM) for CO2 flow in a two-phase ejector was modified in order to increase the accuracy of the numerical simulations The two- phase flow model was implemented on the effective computational tool called ejectorPL for fully automated and systematic computations of various ejector shapes and operating conditions. The modification of the HRM was performed by a change of the relaxation time and the constants included in the relaxation time equation based on the experimental result under the operating conditions typical for the supermarket refrigeration system. The modified HRM was compared to the HEM results, which were performed based on the comparison of motive nozzle and suction nozzle mass flow rates.

  8. Transradial approach to treating endovascular cerebral aneurysms: Case series and technical note

    PubMed Central

    Goland, Javier; Doroszuk, Gustavo Fabián; Garbugino, Silvia Lina; Ypa, María Paula

    2017-01-01

    Background: Several benefits have been described over the years of the transradial versus femoral endovascular approach to cardiac interventions. Consequently, its use has become habitual at most centers that perform cardiac catheterizations. This paper details a right transradial approach, incorporating a variety of coils or flow diverters, which can be utilized for the endovascular treatment of different cerebral aneurysms. Methods: From 2014 to 2016, we performed 40 endovascular procedures to treat cerebral aneurysms adopting the same right transradial approach. Five aneurysms were treated with flow diverters and 35 were treated with coils. Seven of these aneurisms were asymptomatic, whereas 33 had already ruptured. Results: Satisfactory treatment was achieved in all cases through the same approach in the absence of any complications. Conclusions: A right transradial approach may be satisfactory for the endovascular treatment of different cerebral aneurysms, including aneurysms in either hemisphere. This is the largest series of cerebral aneurysms treated through a transradial approach. PMID:28584676

  9. IMA clipping for a type ii endoleak: combined laparoscopic and endovascular approach.

    PubMed

    Zhou, Wei; Lumsden, Alan B; Li, James

    2006-08-01

    We describe herein a combined laparoscopic and endovascular approach to treat a type II endoleak due to retrograde flow in the patent inferior mesenteric artery (IMA). A 61-year-old gentleman presented with enlarging aneurysm sac confirmed on computed tomography scan evaluation after elective endovascular repair of an infrarenal abdominal aortic aneurysm. A combined laparoscopic and endovascular approach was used. After distal IMA was identified and marked with a clip laparoscopically, on-table angiography showed a proximal left colic branch and persistent flow in the IMA. Therefore, further laparoscopic exploration was performed by dissection along the distal branch. The origin of IMA was then located and subsequently sealed with 2 surgical clips. The completion angiography confirmed the proper position of the surgical clips and absence of endoleak. Our case demonstrated useful role of endovascular techniques in identifying the origin of IMA during laparoscopic approach for treating type II endoleak.

  10. The Role of Blood Flow and Blood Flow Modifiers in Clinical Hyperthermia Therapy

    NASA Astrophysics Data System (ADS)

    Olch, Arthur Jacob

    A quantitative assessment of the effect of localized magnetic-loop hyperthermia on blood flow was performed on 12 patients (19 tumor studies) using the Xenon-133 clearance method. After it was discovered that blood flow in most of the tumors increased in response to needle injection, a physiologically based, one compartment model was developed that included both a hyperemic (transient) and a steady state component. In the tumors of six patients, increases in blood flow induced by heat were also observed. The same model was used to describe the measured clearance data for both types of hyperemic response. The ability of tumor vessels to respond dynamically to stress and the degree of response may be predictive of tumor heating efficiency and subsequent therapeutic response. Many tumors treated by hyperthermia, therefore, do not reach therapeutic temperatures (42(DEGREES)C). One explanation for this may be that some tumors react to thermal stress in a manner similar to normal tissues; i.e., they increase blood flow during hyperthermia in order to dissipate heat. Higher temperatures might be achieved in these heat-resistant tumors by administering vasoconstrictive agents in an effort to reduce blood flow. In the second part of this research study, the extent to which pharmacologic inhibition of local blood flow might allow higher temperatures to develop in normal muscles exposed to localized radiofrequency hyperthermia was determined. It was found that the local muscle temperature rise could be increased by at least 90% in dogs and rabbits with the use of a local vasoconstrictive drug.

  11. Modified FlowCAM procedure for quantifying size distribution of zooplankton with sample recycling capacity.

    PubMed

    Wong, Esther; Sastri, Akash R; Lin, Fan-Sian; Hsieh, Chih-Hao

    2017-01-01

    We have developed a modified FlowCAM procedure for efficiently quantifying the size distribution of zooplankton. The modified method offers the following new features: 1) prevents animals from settling and clogging with constant bubbling in the sample container; 2) prevents damage to sample animals and facilitates recycling by replacing the built-in peristaltic pump with an external syringe pump, in order to generate negative pressure, creates a steady flow by drawing air from the receiving conical flask (i.e. vacuum pump), and transfers plankton from the sample container toward the main flowcell of the imaging system and finally into the receiving flask; 3) aligns samples in advance of imaging and prevents clogging with an additional flowcell placed ahead of the main flowcell. These modifications were designed to overcome the difficulties applying the standard FlowCAM procedure to studies where the number of individuals per sample is small, and since the FlowCAM can only image a subset of a sample. Our effective recycling procedure allows users to pass the same sample through the FlowCAM many times (i.e. bootstrapping the sample) in order to generate a good size distribution. Although more advanced FlowCAM models are equipped with syringe pump and Field of View (FOV) flowcells which can image all particles passing through the flow field; we note that these advanced setups are very expensive, offer limited syringe and flowcell sizes, and do not guarantee recycling. In contrast, our modifications are inexpensive and flexible. Finally, we compared the biovolumes estimated by automated FlowCAM image analysis versus conventional manual measurements, and found that the size of an individual zooplankter can be estimated by the FlowCAM image system after ground truthing.

  12. Thoracoabdominal aortic aneurysm repair: current endovascular perspectives

    PubMed Central

    Orr, Nathan; Minion, David; Bobadilla, Joseph L

    2014-01-01

    Thoracoabdominal aneurysms account for roughly 3% of identified aneurysms annually in the United States. Advancements in endovascular techniques and devices have broadened their application to these complex surgical problems. This paper will focus on the current state of endovascular thoracoabdominal aneurysm repair, including specific considerations in patient selection, operative planning, and perioperative complications. Both total endovascular and hybrid options will be considered. PMID:25170271

  13. Endovascular approach to acute aortic trauma

    PubMed Central

    Karmy-Jones, Riyad; Teso, Desarom; Jackson, Nicole; Ferigno, Lisa; Bloch, Robert

    2009-01-01

    Traumatic thoracic aortic injury remains a major cause of death following motor vehicle accidents. Endovascular approaches have begun to supersede open repair, offering the hope of reduced morbidity and mortality. The available endovascular technology is associated with specific anatomic considerations and complications. This paper will review the current status of endovascular management of traumatic thoracic aortic injuries. PMID:21160721

  14. Endovascular Abdominal Aortic Aneurysm Repair in the Presence of a Kidney Transplant: Therapeutic Considerations

    SciTech Connect

    Karkos, Christos D. McMahon, Greg; Fishwick, Guy; Lambert, Kelly; Bagga, Ajay; McCarthy, Mark J.

    2006-04-15

    Abdominal aortic aneurysm (AAA) repair in the presence of a kidney transplant can be extremely challenging, as it carries significant risks of renal ischemia. Endovascular repair is an attractive option, as it can be performed with little or no impairment of renal arterial flow. We describe the endovascular management of a recurrent AAA in a patient with a functioning renal transplant using a custom-made aorto-uni-iliac device. We discuss the planning and the potential problems of the technique.

  15. Paradoxical cerebral air embolism causing large vessel occlusion treated with endovascular aspiration.

    PubMed

    Belton, Patrick J; Nanda, Ashish; Alqadri, Syeda L; Khakh, Gurpreet S; Chandrasekaran, Premkumar Nattanmai; Newey, Christopher; Humphries, William E

    2017-04-01

    Cerebral air embolism is a dreaded complication of invasive medical procedures. The mainstay of therapy for patients with cerebral air embolism has been hyperbaric oxygen therapy, high flow oxygen therapy, and anticonvulsants. We present a novel therapeutic approach for treatment of cerebral air embolism causing large vessel occlusion, using endovascular aspiration. Our patient developed a cerebral air embolism following sclerotherapy for varicose veins. This caused near total occlusion of the superior division of the M2 segment of the right middle cerebral artery. Symptoms included unilateral paralysis, unintelligible speech, and hemianopia; National Institutes of Health Stroke Scale (NIHSS) on presentation was 16. The air embolism was treated using a distal aspiration technique. Angiography following aspiration showed Thrombolysis in Cerebral Infarction 2B reperfusion. Following aspiration, the patient was re-examined; NIHSS at that time was 4. At 1 month follow-up, the modified Rankin Scale score was 1 and NIHSS was 1. Treatment of cerebral air embolism is discussed.

  16. Endovascular management of intracranial blister aneurysms: spectrum and limitations of contemporary techniques.

    PubMed

    Ashour, Ramsey; Dodson, Stephen; Aziz-Sultan, M Ali

    2016-01-01

    Intracranial blister aneurysms are rare lesions that are notoriously more difficult to treat than typical saccular aneurysms. High complication rates associated with surgery have sparked considerable interest in endovascular techniques, though not well-studied, to treat blister aneurysms. To evaluate our experience using various endovascular approaches to treat blister aneurysms. All consecutive blister aneurysms treated using an endovascular approach by the study authors over a 3-year period were retrospectively analyzed. A literature review was also performed. Nine patients with blister aneurysms underwent 11 endovascular interventions. In various combinations, stents were used in 8/11, coils in 5/11, and Onyx in 3/11 procedures. At mean angiographic follow-up of 200 days, 8/9 aneurysms were completely occluded by endovascular means alone requiring no further treatment and 1/9 aneurysms required surgical bypass/trapping after one failed surgical and two failed endovascular treatments. At mean clinical follow-up of 416 days, modified Rankin Scale scores were improved in six patients, stable in two, and worsened in one patient. One complication occurred in 11 procedures (9%), resulting in a permanent neurologic deficit. No unintended endovascular parent vessel sacrifice, intraprocedural aneurysmal ruptures, antiplatelet-related complications, post-treatment aneurysmal re-ruptures, or deaths occurred. This series highlights both the spectrum and limitations of endovascular techniques currently used to treat blister aneurysms, including a novel application of stent-assisted Onyx embolization. Long-term follow-up and experience in larger studies are required to better define the role of endovascular therapy in the management of these difficult lesions. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  17. Intraoperative endovascular ultrasonography

    NASA Astrophysics Data System (ADS)

    Eton, Darwin; Ahn, Samuel S.; Baker, J. D.; Pensabene, Joseph; Yeatman, Lawrence S.; Moore, Wesley S.

    1991-05-01

    The early experience using intra-operative endovascular ultrasonography (EU) is reported in eight patients undergoing lower extremity revasularization. In four patients, intra-operative EU successfully characterized inflow stenoses that were inadequately imaged with pre- operative arteriography. Two patients were found to have hemodynamically significant inflow stenoses, and were treated with intra-operative balloon angioplasty followed by repeat EU. The other two patients were found to have non-hemodynamically significant inflow stenoses requiring no treatment. Additional outflow procedures were required in all four patients. In the remaining four patients, EU was used to evaluate the completeness of TEC rotary atherectomy, of Hall oscillatory endarterectomy, of thrombectomy of the superficial femoral and popliteal arteries, and of valve lysis during in situ saphenous vein grafting, respectively. In the latter case, the valve leaflets were not clearly seen. In the other cases, EU assisted the surgeon. Angioscopy and angiography were available for comparison. In one case, angioscopy failed because of inability to clear the field while inspecting retrograde the limb of an aorto-bi-femoral graft. EU however was possible. No complications of EU occurred. EU is a safe procedure indicated when characterization of a lesion is needed prior to an intervention or when evaluation of the intervention's success is desired. We did not find it useful in valve lysis for in-site grafting.

  18. Imaging in Endovascular Stroke Trials

    PubMed Central

    Malhotra, Konark; Liebeskind, David S

    2015-01-01

    Ischemic stroke remains a leading cause of death and disability worldwide. Various endovascular trials have addressed clinical outcomes without elucidating the impact of imaging studies in patient selection. The success of recent endovascular trials was bolstered by the use of advanced imaging techniques for optimal selection of reperfusion candidates. This seminal juncture in the history of stroke trials warrants further consideration on the use of imaging to guide future refinements in the treatment of acute stroke. In this article, we systematically review the imaging methodology and key facets used in all published endovascular stroke trials to date, discuss the success of recent trials using latest advanced imaging techniques and focus on the importance of imaging studies for future patient selection. PMID:26179500

  19. Signal quality of endovascular electroencephalography

    NASA Astrophysics Data System (ADS)

    He, Bryan D.; Ebrahimi, Mosalam; Palafox, Leon; Srinivasan, Lakshminarayan

    2016-02-01

    Objective, Approach. A growing number of prototypes for diagnosing and treating neurological and psychiatric diseases are predicated on access to high-quality brain signals, which typically requires surgically opening the skull. Where endovascular navigation previously transformed the treatment of cerebral vascular malformations, we now show that it can provide access to brain signals with substantially higher signal quality than scalp recordings. Main results. While endovascular signals were known to be larger in amplitude than scalp signals, our analysis in rabbits borrows a standard technique from communication theory to show endovascular signals also have up to 100× better signal-to-noise ratio. Significance. With a viable minimally-invasive path to high-quality brain signals, patients with brain diseases could one day receive potent electroceuticals through the bloodstream, in the course of a brief outpatient procedure.

  20. Endovascular Treatment of Internal Iliac Artery Aneurysms: Single Center Experience

    PubMed Central

    Machado, Rui Manuel; Rego, Duarte Nuno Cunha; de Oliveira, Pedro Nuno Ferreira Pinto; de Almeida, Rui Manuel Gonçalves Fernandes

    2016-01-01

    Objective Internal iliac artery aneurysms (IIAA) are rare, representing only 0.3% of aortoiliac aneurysms. Its treatment with open surgery is complex and associated with high morbidity and mortality, which led to increasing application of endovascular solutions. In this study, we aimed to evaluate outcomes of endovascular aneurysm repair (EVAR) of IIAA in one institution. Methods We retrospectively reviewed all cases of IIAA treated with endovascular techniques between 2003 and 2014. Endpoints were morbidity, mortality, freedom from pelvic ischemic symptoms (buttock claudication, ischemic colitis, and spinal cord injury), and need for reintervention. Results There were 16 patients, 13 males and 3 females, with mean age of 75.1±7 years. A total of 20 IIAA (4 cases were bilateral), with mean diameter of 37.9 mm, were treated. EVAR was performed in 13 (81.3%) patients, with associated internal iliac artery's outflow occlusion in 2. Iliac branch device was used in one patient. Two patients underwent endovascular IIAA embolization alone. One patient underwent percutaneous, transgluteal, IIAA embolization. IIAA flow preservation in at least one internal iliac artery was possible in 9 (56.3%) patients. Early mortality was 7% (1 case). Early morbidity was 18.8%. Pelvic ischemic complications occurred in 1 (7%) patient with buttock claudication. Late reintervention was needed in 3 patients, none of them for IIAA related complications. Conclusion Endovascular treatment of IIAA is technically feasible and durable. Although overall morbidity is relatively high, major complications are infrequent and perioperative mortality is low. internal iliac artery flow preservation is technically challenging and, in a significant number of cases, not possible at all. PMID:27556311

  1. Radiation exposure during endovascular procedures.

    PubMed

    Lekovic, Gregory P; Kim, Louis J; Gonzalez, L Fernando; Bice, Alden; Albuquerque, Felipe C; McDougall, Cameron G

    2008-07-01

    The duration of fluoroscopy exposure is routinely recorded as part of endovascular procedures. However, to better relate the duration of exposure to actual doses of surface and intracranial radiation, we compared surface doses during endovascular procedures with intracranial doses in a cadaver model exposed to lateral fluoroscopy. Optically stimulated luminescence dosimeter chips (Landauer, Glenwood, IL) were used to measure the cranial surface dose of three consecutive patients undergoing endovascular procedures. Bitemporal craniotomies were performed on a cadaver. Dosimeter chips were placed on both the ipsilateral and contralateral skin and meningeal surfaces, and the cadaver was exposed to lateral fluoroscopy. Finally, to assess mean fluoroscopy times in patients undergoing embolization procedures, the operative notes of 100 consecutive patients were reviewed. Three patients undergoing endovascular treatment received peak doses of 0.24, 0.31, and 1.38 Gy, respectively. In the cadaver, the peak surface dose recorded after 120 minutes of exposure was 1.71 Gy. The cranium and scalp absorbed or reflected 29% of the surface dose. Time in minutes of fluoroscopy was found to correlate with surface dose (R2 = 0.925). Our data show that radiation exposure during endovascular treatment can reach clinically significant levels. The surface doses recorded during this study were comparable to the mean dose of 1.5 Gy estimated by others to increase the relative risk of inducing meningiomas, gliomas, and nerve sheath tumors. Pending long-term follow-up of patients exposed to endovascular procedures, consent for possible long-term sequelae of radiation may be warranted.

  2. The analysis of MHD blood flows through porous arteries using a locally modified homogenous nanofluids model.

    PubMed

    Akbarzadeh, Pooria

    2016-05-12

    In this paper, magneto-hydrodynamic blood flows through porous arteries are numerically simulated using a locally modified homogenous nanofluids model. Blood is taken into account as the third-grade non-Newtonian fluid containing nanoparticles. In the modified nanofluids model, the viscosity, density, and thermal conductivity of the solid-liquid mixture (nanofluids) which are commonly utilized as an effective value, are locally combined with the prevalent single-phase model. The modified governing equations are solved numerically using Newton's method and a block tridiagonal matrix solver. The results are compared to the prevalent nanofluids single-phase model. In addition, the efficacies of important physical parameters such as pressure gradient, Brownian motion parameter, thermophoresis parameter, magnetic-field parameter, porosity parameter, and etc. on temperature, velocity and nanoparticles concentration profiles are examined.

  3. Insights on a Giant Aneurysm Treated Endovascularly.

    PubMed

    Graziano, Francesca; Iacopino, Domenico Gerardo; Ulm, Arthur John

    2016-07-01

    Background Endovascular treatment with stent-assisted Guglielmi detachable coils is an accepted method for treating intracranial giant aneurysms that otherwise would require more invasive or destructive treatment or could not be treated at all. Nevertheless, there is a paucity of information concerning inner postcoiling aneurysmal changes in human subjects over the long term. We report a postmortem analysis of a patient with a giant aneurysm at the vertebrobasilar junction (VBJ) who was treated endovascularly and studied pathologically 24 months after treatment. Materials and Method The head was removed at autopsy and prefixed in a 10% neutral buffered formalin solution. The brain was gently removed from the skull base after cutting the intracranial nerves and vascular structures. The giant VBJ aneurysm and its relationship with the brainstem, cranial nerves, and vessels were captured photographically and analyzed. Afterward, under operating microscope guidance, the vertebrobasilar system with the aneurysm was gently and carefully detached from the brainstem and carefully analyzed. Results No complete fibrous obliteration of the aneurysm lumen could be detected in our case, and no endothelialization had taken place 24 months after treatment. Conclusions Our findings agree with those of previous similar reports. Coiling, in particular in large or giant aneurysms, may be burdened by the risk of coil compaction and recanalization, but it has the advantage of not affecting the flow in the perforating arteries.

  4. Endovascular Management of May–Thurner Syndrome

    PubMed Central

    Zhang, Xueqiang; Shi, Xiuhua; Gao, Pingrui; Wang, Junbo; Li, Shusen; Yao, Shuge; Zhang, Xuefeng; Huo, Ji; Wang, Jianfeng

    2016-01-01

    Abstract May–Thurner syndrome (MTS) is caused by venous occlusion because of compression of the iliac vein by the iliac artery and vertebral body, leading to left lower extremity deep venous thrombosis, eventually resulting in a series of symptoms. Endovascular treatment has now become the most preferred method of treatment of MTS. The authors report a 66-year-old woman who was hospitalized because of increasing swelling in her left lower limb for almost 2 weeks. Ultrasonography performed upon admission indicated MTS, and venography revealed occlusion of the left common iliac vein and massive thrombosis in the left external iliac and femoral veins. The left lower extremity venous blood flow returned to normal after the patient underwent manual aspiration thrombectomy using a guide catheter, followed by balloon angioplasty and stent placement. The patient achieved complete remission after 1 week and had no in-stent restenosis during the 1-year follow-up. Endovascular treatment is a safe and effective treatment of MTS. PMID:26825895

  5. Mercury adsorption characteristics of HBr-modified fly ash in an entrained-flow reactor.

    PubMed

    Zhang, Yongsheng; Zhao, Lilin; Guo, Ruitao; Song, Na; Wang, Jiawei; Cao, Yan; Orndorff, William; Pan, Wei-ping

    2015-07-01

    In this study, the mercury adsorption characteristics of HBr-modified fly ash in an entrained-flow reactor were investigated through thermal decomposition methods. The results show that the mercury adsorption performance of the HBr-modified fly ash was enhanced significantly. The mercury species adsorbed by unmodified fly ash were HgCl2, HgS and HgO. The mercury adsorbed by HBr-modified fly ash, in the entrained-flow reactor, existed in two forms, HgBr2 and HgO, and the HBr was the dominant factor promoting oxidation of elemental mercury in the entrained-flow reactor. In the current study, the concentration of HgBr2 and HgO in ash from the fine ash vessel was 4.6 times greater than for ash from the coarse ash vessel. The fine ash had better mercury adsorption performance than coarse ash, which is most likely due to the higher specific surface area and longer residence time. Copyright © 2015. Published by Elsevier B.V.

  6. Techniques in Endovascular Aneurysm Repair

    PubMed Central

    Phade, Sachin V.; Garcia-Toca, Manuel; Kibbe, Melina R.

    2011-01-01

    Endovascular repair of infrarenal abdominal aortic aneurysms (EVARs) has revolutionized the treatment of aortic aneurysms, with over half of elective abdominal aortic aneurysm repairs performed endoluminally each year. Since the first endografts were placed two decades ago, many changes have been made in graft design, operative technique, and management of complications. This paper summarizes modern endovascular grafts, considerations in preoperative planning, and EVAR techniques. Specific areas that are addressed include endograft selection, arterial access, sheath delivery, aortic branch management, graft deployment, intravascular ultrasonography, pressure sensors, management of endoleaks and compressed limbs, and exit strategies. PMID:22121487

  7. Experimental and numerical study of electrically driven magnetohydrodynamic flow in a modified cylindrical annulus. I. Base flow

    NASA Astrophysics Data System (ADS)

    Stelzer, Zacharias; Cébron, David; Miralles, Sophie; Vantieghem, Stijn; Noir, Jérôme; Scarfe, Peter; Jackson, Andrew

    2015-07-01

    Shear layers in confined liquid metal magnetohydrodynamic (MHD) flow play an important role in geo- and astrophysical bodies as well as in engineering applications. We present an experimental and numerical study of liquid metal MHD flow in a modified cylindrical annulus that is driven by an azimuthal Lorentz force resulting from a forced electric current under an imposed axial magnetic field. Hartmann and Reynolds numbers reach Mmax ≈ 2000 and Remax ≈ 1.3 × 104, respectively, in the steady regime. The peculiarity of our model geometry is the protruding inner disk electrode which gives rise to a free Shercliff layer at its edge. The flow of liquid GaInSn in the experimental device ZUCCHINI (ZUrich Cylindrical CHannel INstability Investigation) is probed with ultrasound Doppler velocimetry. We establish the base flow in ZUCCHINI and study the scaling of velocities and the free Shercliff layer in both experiment and finite element simulations. Experiment and numerics agree well on the mean azimuthal velocity uϕ(r) following the prediction of a large-M theoretical model. The large-M limit, which is equivalent to neglecting inertial effects, appears to be reached for M ≳ 30 in our study. In the numerics, we recover the theoretical scaling of the free Shercliff layer δS ˜ M-1/2 whereas δS appears to be largely independent of M in the experiment.

  8. The transient intraluminal filament middle cerebral artery occlusion model as a model of endovascular thrombectomy in stroke.

    PubMed

    Sutherland, Brad A; Neuhaus, Ain A; Couch, Yvonne; Balami, Joyce S; DeLuca, Gabriele C; Hadley, Gina; Harris, Scarlett L; Grey, Adam N; Buchan, Alastair M

    2016-02-01

    The clinical relevance of the transient intraluminal filament model of middle cerebral artery occlusion (tMCAO) has been questioned due to distinct cerebral blood flow profiles upon reperfusion between tMCAO (abrupt reperfusion) and alteplase treatment (gradual reperfusion), resulting in differing pathophysiologies. Positive results from recent endovascular thrombectomy trials, where the occluding clot is mechanically removed, could revolutionize stroke treatment. The rapid cerebral blood flow restoration in both tMCAO and endovascular thrombectomy provides clinical relevance for this pre-clinical model. Any future clinical trials of neuroprotective agents as adjuncts to endovascular thrombectomy should consider tMCAO as the model of choice to determine pre-clinical efficacy.

  9. Vertebro-basilar junction aneurysms: a single centre experience and meta-analysis of endovascular treatments.

    PubMed

    Graziano, Francesca; Ganau, Mario; Iacopino, Domenico Gerardo; Boccardi, Edoardo

    2014-12-01

    Vascular lesions of the vertebrobasilar junction (VBJ) are challenging in neurosurgical practice, and their gold-standard therapy is still under debate. We describe the operative strategies currently in use for the management of these complex vascular lesions and discuss their rationale in a literature meta-analysis and single centre blinded retrospective study. The single centre study included a review of initial presentation, angiographic features and clinical outcome (with modified Rankin Scale [mRS] scores) over a long-term follow-up. In our series, small aneurysms were effectively treated by endosaccular coil embolization, whereas a strategy including flow-diverter devices combined with endosaccular coil embolization was the option of choice in large and giant aneurysms, leading to satisfactory outcomes in most cases. Our Medline review showed that endovascular treatment was chosen in most VBJ cases, whereas the microsurgical option was assigned to only a few cases. Among the endovascular treatments, the most common techniques used for the treatment of VBJ aneurysms were: coiling, stent-assisted coiling and flow diversion. Our study highlights that aneurysm morphology, location and patient-specific angio-architecture are key factors to be considered in the management of VBJ aneurysms. Most case series, including our own, show that parent artery reconstruction using a flow-diverter device is a feasible and successful technique in some cases of giant and complex aneurysms (especially those involving the lower third of the basilar artery) while a "sit back, wait and see" approach may represent the safest and most reasonable option.

  10. Vertebro-Basilar Junction Aneurysms: A Single Centre Experience and Meta-Analysis of Endovascular Treatments

    PubMed Central

    Graziano, Francesca; Ganau, Mario; Iacopino, Domenico Gerardo; Boccardi, Edoardo

    2014-01-01

    Summary Vascular lesions of the vertebrobasilar junction (VBJ) are challenging in neurosurgical practice, and their gold-standard therapy is still under debate. We describe the operative strategies currently in use for the management of these complex vascular lesions and discuss their rationale in a literature meta-analysis and single centre blinded retrospective study. The single centre study included a review of initial presentation, angiographic features and clinical outcome (with modified Rankin Scale [mRS] scores) over a long-term follow-up. In our series, small aneurysms were effectively treated by endosaccular coil embolization, whereas a strategy including flow-diverter devices combined with endosaccular coil embolization was the option of choice in large and giant aneurysms, leading to satisfactory outcomes in most cases. Our Medline review showed that endovascular treatment was chosen in most VBJ cases, whereas the microsurgical option was assigned to only a few cases. Among the endovascular treatments, the most common techniques used for the treatment of VBJ aneurysms were: coiling, stent-assisted coiling and flow diversion. Our study highlights that aneurysm morphology, location and patient-specific angio-architecture are key factors to be considered in the management of VBJ aneurysms. Most case series, including our own, show that parent artery reconstruction using a flow-diverter device is a feasible and successful technique in some cases of giant and complex aneurysms (especially those involving the lower third of the basilar artery) while a "sit back, wait and see" approach may represent the safest and most reasonable option. PMID:25489898

  11. DNA Detection by Flow Cytometry using PNA-Modified Metal-Organic Framework Particles.

    PubMed

    Mejia-Ariza, Raquel; Rosselli, Jessica; Breukers, Christian; Manicardi, Alex; Terstappen, Leon W M M; Corradini, Roberto; Huskens, Jurriaan

    2017-03-23

    A DNA-sensing platform is developed by exploiting the easy surface functionalization of metal-organic framework (MOF) particles and their highly parallelized fluorescence detection by flow cytometry. Two strategies were employed to functionalize the surface of MIL-88A, using either covalent or non-covalent interactions, resulting in alkyne-modified and biotin-modified MIL-88A, respectively. Covalent surface coupling of an azide-dye and the alkyne-MIL-88A was achieved by means of a click reaction. Non-covalent streptavidin-biotin interactions were employed to link biotin-PNA to biotin-MIL-88A particles mediated by streptavidin. Characterization by confocal imaging and flow cytometry demonstrated that DNA can be bound selectively to the MOF surface. Flow cytometry provided quantitative data of the interaction with DNA. Making use of the large numbers of particles that can be simultaneously processed by flow cytometry, this MOF platform was able to discriminate between fully complementary, single-base mismatched, and randomized DNA targets. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  12. Modified harvest system for enhancing Factor VIII yield in alternating tangential flow perfusion culture.

    PubMed

    Kim, Seung-Chul; An, Sora; Kim, Hyun-Ki; Park, Beom-Soo; Na, Kyu-Heum; Kim, Byung-Gee

    2016-05-01

    This study describes the development and experimental verification of a modified harvest system to enhance Factor VIII (FVIII) yield in an alternating tangential flow (ATF) perfusion culture. The main innovation of the modified harvest system is the use of check and pinch valves, eliminating the need of a peristaltic pump for harvest. The system was applied to perfusion cultures of Chinese hamster ovary cells, which co-express both recombinant human FVIII (rhFVIII) and von Willebrand factor (vWF). The modified harvest system showed comparable cell growth with the conventional harvest system using a peristaltic pump. The perfusion rate was successfully controlled using the system. In addition, the modified harvest system achieved an approximately 13.6-fold increase in the final concentration yield of FVIII activity and a 1.47-fold increase in the production yield of FVIII activity compared with a peristaltic pump. Enhancement of the yield of FVIII activity resulted from the reduction of FVIII antigen ( Ag) retention. As a result of transmembrane pressure (TMP) measurement, the reduction of the retained Ag was due to the increased TMP, which was caused by the characteristic function of a check valve, compared with a peristaltic harvest system. The modified harvest system developed in this study could be useful to enhance the production yield of other recombinant proteins in ATF perfusion culture. Copyright © 2015. Published by Elsevier B.V.

  13. Shallow subsurface storm flow in a forested headwater catchment: Observations and modeling using a modified TOPMODEL

    USGS Publications Warehouse

    Scanlon, T.M.; Raffensperger, J.P.; Hornberger, G.M.; Clapp, R.B.

    2000-01-01

    Transient, perched water tables in the shallow subsurface are observed at the South Fork Brokenback Run catchment in Shenandoah National Park, Virginia. Crest piezometers installed along a hillslope transect show that the development of saturated conditions in the upper 1.5 m of the subsurface is controlled by total precipitation and antecedent conditions, not precipitation intensity, although soil heterogeneities strongly influence local response. The macroporous subsurface storm flow zone provides a hydrological pathway for rapid runoff generation apart from the underlying groundwater zone, a conceptualization supported by the two-storage system exhibited by hydrograph recession analysis. A modified version of TOPMODEL is used to simulate the observed catchment dynamics. In this model, generalized topographic index theory is applied to the subsurface storm flow zone to account for logarithmic storm flow recessions, indicative of linearly decreasing transmissivity with depth. Vertical drainage to the groundwater zone is required, and both subsurface reservoirs are considered to contribute to surface saturation.

  14. Using ion flows parallel and perpendicular to gravity to modify dust acoustic waves

    NASA Astrophysics Data System (ADS)

    Thomas, E.; Fisher, R.

    2008-11-01

    Recent studies of dust acoustic waves have shown that the dust kinetic temperature can play an important role in determining the resulting dispersion relation [M. Rosenberg, et al., Phys. Plasmas, 15, 073701 (2008)]. In these studies, it is believed that ion flows play a dominant role in determining both the kinetic temperature of the charged microparticles as well as providing the source of energy for triggering the waves. In this presentation, results will be presented on the effects of ion flow on spatial structure and velocity distribution of dust acoustic waves. Here, the waves will be formed in dusty plasmas consisting of 3 ± 1 micron diameter silica microspheres. Two separate electrodes will be used to modify the ion flow in the plasma -- one parallel to the direction of gravity and one perpendicular to the direction of gravity. Particle image velocimetry (PIV) techniques will be used to observe the particles and to measure their velocity distributions.

  15. Echo-acoustic flow dynamically modifies the cortical map of target range in bats

    NASA Astrophysics Data System (ADS)

    Bartenstein, Sophia K.; Gerstenberg, Nadine; Vanderelst, Dieter; Peremans, Herbert; Firzlaff, Uwe

    2014-08-01

    Echolocating bats use the delay between their sonar emissions and the reflected echoes to measure target range, a crucial parameter for avoiding collisions or capturing prey. In many bat species, target range is represented as an orderly organized map of echo delay in the auditory cortex. Here we show that the map of target range in bats is dynamically modified by the continuously changing flow of acoustic information perceived during flight (‘echo-acoustic flow’). Combining dynamic acoustic stimulation in virtual space with extracellular recordings, we found that neurons in the auditory cortex of the bat Phyllostomus discolor encode echo-acoustic flow information on the geometric relation between targets and the bat’s flight trajectory, rather than echo delay per se. Specifically, the cortical representation of close-range targets is enlarged when the lateral passing distance of the target decreases. This flow-dependent enlargement of target representation may trigger adaptive behaviours such as vocal control or flight manoeuvres.

  16. Security Constrained Optimal Power Flow with FACTS Devices Using Modified Particle Swarm Optimization

    NASA Astrophysics Data System (ADS)

    Somasundaram, P.; Muthuselvan, N. B.

    This paper presents new computationally efficient improved Particle Swarm algorithms for solving Security Constrained Optimal Power Flow (SCOPF) in power systems with the inclusion of FACTS devices. The proposed algorithms are developed based on the combined application of Gaussian and Cauchy Probability distribution functions incorporated in Particle Swarm Optimization (PSO). The power flow algorithm with the presence of Static Var Compensator (SVC) Thyristor Controlled Series Capacitor (TCSC) and Unified Power Flow Controller (UPFC), has been formulated and solved. The proposed algorithms are tested on standard IEEE 30-bus system. The analysis using PSO and modified PSO reveals that the proposed algorithms are relatively simple, efficient, reliable and suitable for real-time applications. And these algorithms can provide accurate solution with fast convergence and have the potential to be applied to other power engineering problems.

  17. Intracranial pediatric aneurysms: endovascular treatment and its outcome.

    PubMed

    Saraf, Rashmi; Shrivastava, Manish; Siddhartha, Wuppalapati; Limaye, Uday

    2012-09-01

    The aim of this study was to analyze the location, clinical presentation, and morphological characteristics of pediatric aneurysms and the safety, feasibility, and durability of endovascular treatment. The authors conducted a retrospective study of all cases involving patients 18 years old or younger who underwent endovascular treatment for pediatric aneurysms at their institution between July 1998 and July 2010. The clinical presentation, aneurysm location, endovascular management, and treatment outcome were studied. During the study period, 23 pediatric patients (mean age 13 years, range 2 months-18 years) were referred to the authors' department and underwent endovascular treatment for aneurysms. The aneurysms were saccular in 6 cases, dissecting in 4, infectious in 5, and giant partially thrombosed lesions in 8. Fourteen of the aneurysms were ruptured, and 9 were unruptured. Thirteen were in the anterior circulation and 10 in the posterior circulation. The most common location in the anterior circulation was the anterior communicating artery; in the posterior circulation, the most common location was the basilar artery. Saccular aneurysms were the most common type in the anterior circulation; and giant partially thrombosed and dissecting aneurysms were the most common types in the posterior circulation. Coil embolization was performed in 7 cases, parent vessel sacrifice in 10, flow reversal in 3, glue embolization in 2, and stent placement in 1. Immediate angiographic cure was seen in 21 (91%) of 23 patients. Complications occurred in 4 patients, 3 of whom eventually had a good outcome. No patient died. Overall, a favorable outcome was seen in 22 (96%) of 23 patients. Follow-up showed stable occlusion of aneurysms in 96% of the patients. Pediatric aneurysms are rare. Their clinical presentation varies from intracranial hemorrhage to mass effect. They may also be found incidentally. Among pediatric patients with aneurysms, giant aneurysms are relatively common

  18. Alosetron, cilansetron and tegaserod modify mesenteric but not colonic blood flow in rats.

    PubMed

    Painsipp, Evelin; Shahbazian, Anaid; Holzer, Peter

    2009-11-01

    As the use of the 5-HT(3) receptor antagonist alosetron (GlaxoSmithKline) and the 5-HT(4) receptor agonist tegaserod (Novartis) in patients with irritable bowel syndrome has been associated with cases of ischaemic colitis, the effects of alosetron, cilansetron (Solvay) and tegaserod on the rat splanchnic circulation were evaluated. Phenobarbital-anaesthetised rats were instrumented to record blood flow in the superior mesenteric artery and transverse colon and to calculate mesenteric and colonic vascular conductance. Intravenous alosetron (0.03-0.3 mg.kg(-1)) did not alter blood pressure or heart rate but reduced mesenteric blood flow and vascular conductance by 15-20%. This activity profile was also seen after intraduodenal alosetron and shared by the 5-HT(3) receptor antagonist cilansetron. In contrast, blood flow, vascular conductance and intraluminal pressure in the colon were not modified by alosetron and cilansetron. Intravenous or intraduodenal tegaserod (0.3-1.0 mg.kg(-1)) had no inhibitory effect on mesenteric and colonic blood flow. Peroral treatment of rats with alosetron or tegaserod for 7 days did not modify mesenteric haemodynamics at baseline and after blockade of nitric oxide synthesis. Mild inflammation induced by dextran sulphate sodium failed to provoke a vasoconstrictor effect of cilansetron in the colon. Alosetron and cilansetron, not tegaserod, caused a small and transient constriction of the rat mesenteric vascular bed, whereas blood flow in the colon remained unaltered. The relevance of these findings to the treatment-associated occurrence of ischaemic colitis in patients with irritable bowel syndrome remains open.

  19. Chronic Fluid Flow Is an Environmental Modifier of Renal Epithelial Function

    PubMed Central

    Resnick, Andrew

    2011-01-01

    Although solitary or sensory cilia are present in most cells of the body and their existence has been known since the sixties, very little is been known about their functions. One suspected function is fluid flow sensing- physical bending of cilia produces an influx of Ca++, which can then result in a variety of activated signaling pathways. Autosomal Dominant Polycystic Kidney Disease (ADPKD) is a progressive disease, typically appearing in the 5th decade of life and is one of the most common monogenetic inherited human diseases, affecting approximately 600,000 people in the United States. Because ADPKD is a slowly progressing disease, I asked how fluid flow may act, via the primary cilium, to alter epithelial physiology during the course of cell turnover. I performed an experiment to determine under what conditions fluid flow can result in a change of function of renal epithelial tissue. A wildtype epithelial cell line derived the cortical collecting duct of a heterozygous offspring of the Immortomouse (Charles River Laboratory) was selected as our model system. Gentle orbital shaking was used to induce physiologically relevant fluid flow, and periodic measurements of the transepithelial Sodium current were performed. At the conclusion of the experiment, mechanosensitive proteins of interest were visualized by immunostaining. I found that fluid flow, in itself, modifies the transepithelial sodium current, cell proliferation, and the actin cytoskeleton. These results significantly impact the understanding of both the mechanosensation function of primary cilia as well as the understanding of ADPKD disease progression. PMID:22046444

  20. Experimental and numerical study of electrically driven magnetohydrodynamic flow in a modified cylindrical annulus. II. Instabilities

    NASA Astrophysics Data System (ADS)

    Stelzer, Zacharias; Miralles, Sophie; Cébron, David; Noir, Jérôme; Vantieghem, Stijn; Jackson, Andrew

    2015-08-01

    We present an investigation of the stability of liquid metal flow under the influence of an imposed magnetic field by means of a laboratory experiment as well as a linear stability analysis of the setup using the finite element method. The experimental device ZUrich Cylindrical CHannel INstability Investigation is a modified cylindrical annulus with electrically driven flow of liquid GaInSn operating at Hartmann and Reynolds numbers up to M = 2022 and Re = 2.6 ṡ 105, respectively. The magnetic field gives rise to a free shear layer at the prominent inner electrode. We identify several flow regimes characterized by the nature of the instabilities. Above a critical current I c = O ( 0 . 1 A ) , the steady flow is destabilized by a Kelvin-Helmholtz mechanism at the free shear layer. The instability consists of counterrotating vortices traveling with the mean flow. For low forcing, the vortices are restricted to the free shear layer. Their azimuthal wave number m grows with M and decreases with Re. At Re/M ≈ 25, the instability becomes container-filling and energetically significant. It enhances the radial momentum transport which manifests itself in a broadening of the free shear layer width δS. We propose that this transition may be related to an unstable Hartmann layer. At R e / M 2 = O ( 1 ) , an abrupt change is observed in the mean azimuthal velocity < u ϕ ¯ > and the friction factor F, which we interpret as the transition between an inertialess and an inertial regime.

  1. Chronic fluid flow is an environmental modifier of renal epithelial function.

    PubMed

    Resnick, Andrew

    2011-01-01

    Although solitary or sensory cilia are present in most cells of the body and their existence has been known since the sixties, very little is been known about their functions. One suspected function is fluid flow sensing- physical bending of cilia produces an influx of Ca(++), which can then result in a variety of activated signaling pathways. Autosomal Dominant Polycystic Kidney Disease (ADPKD) is a progressive disease, typically appearing in the 5(th) decade of life and is one of the most common monogenetic inherited human diseases, affecting approximately 600,000 people in the United States. Because ADPKD is a slowly progressing disease, I asked how fluid flow may act, via the primary cilium, to alter epithelial physiology during the course of cell turnover. I performed an experiment to determine under what conditions fluid flow can result in a change of function of renal epithelial tissue. A wildtype epithelial cell line derived the cortical collecting duct of a heterozygous offspring of the Immortomouse (Charles River Laboratory) was selected as our model system. Gentle orbital shaking was used to induce physiologically relevant fluid flow, and periodic measurements of the transepithelial Sodium current were performed. At the conclusion of the experiment, mechanosensitive proteins of interest were visualized by immunostaining. I found that fluid flow, in itself, modifies the transepithelial sodium current, cell proliferation, and the actin cytoskeleton. These results significantly impact the understanding of both the mechanosensation function of primary cilia as well as the understanding of ADPKD disease progression.

  2. Numerical simulation of supersonic jet flow using a modified k-ɛ model

    NASA Astrophysics Data System (ADS)

    Tandra, D. S.; Kaliazine, A.; Cormack, D. E.; Tran, H. N.

    2006-01-01

    Many papers have reported that the standard k-ɛ model fails to accurately predict the mean velocity profile of turbulent axisymmetric jets (Thies and Tam, Computation of turbulent axisymmetric and nonaxisymmetric jet flows using the K-ɛ model, AIAA J., 1996, 34(2), 309 316; Pope, Turbulent Flows, 2002 (Cambridge University press: Cambridge). As the jet velocity increases, the deviation of the model with respect to the experimental measurements also increases. This work is aimed at the development of a modified k-ɛ model that can be used to predict the mean properties of an axisymmetric jet as it (i) flows as a free jet, (ii) propagates between walls, and (iii) impinges on a solid object. Three additional terms are proposed to improve the standard k-ɛ model predictions. They are Durbin realizable, Heinz turbulence production and Sarkar compressibility correction terms. The performance of the modified model in predicting the velocity and the impact pressure profiles of a free jet with an exit Mach number range of 0.6 2.8 has been confirmed by its close agreement with the experimental measurements. In addition, the study suggests that the model is also capable of predicting the impact pressure of a supersonic jet propagating between smooth walls and impinging on the front edge of the wall in various degrees of intensity.

  3. Tensile properties and flow behavior analysis of modified 9Cr-1Mo steel clad tube material

    NASA Astrophysics Data System (ADS)

    Singh, Kanwarjeet; Latha, S.; Nandagopal, M.; Mathew, M. D.; Laha, K.; Jayakumar, T.

    2014-11-01

    The tensile properties and flow behavior of modified 9Cr-1Mo steel clad tube have been investigated in the framework of various constitutive equations for a wide range of temperatures (300-923 K) and strain rates (3 × 10-3 s-1, 3 × 10-4 s-1 and 3 × 10-5 s-1). The tensile flow behavior of modified 9Cr-1Mo steel clad tube was most accurately described by Voce equation. The variation of instantaneous work hardening rate (θ = dσ/dε) and σθ with stress (σ) indicated two stage behavior characterized by rapid decrease at low stresses (transient stage) followed by a gradual decrease in high stresses (Stage III). The variation of work hardening parameters and work hardening rate in terms of θ vs. σ and σθ vs. σ with temperature exhibited three distinct regimes. Rapid decrease in flow stress and work hardening parameters and rapid shift of θ vs. σ and σθ vs. σ towards low stresses with increase in temperature indicated dynamic recovery at high temperatures. Tensile properties of the material have been best predicted from Voce equation.

  4. Rapid detection of genetically modified organisms on a continuous-flow polymerase chain reaction microfluidics.

    PubMed

    Li, Yuyuan; Xing, Da; Zhang, Chunsun

    2009-02-01

    The ability to perform DNA amplification on a microfluidic device is very appealing. In this study, a compact continuous-flow polymerase chain reaction (PCR) microfluidics was developed for rapid analysis of genetically modified organisms (GMOs) in genetically modified soybeans. The device consists of three pieces of copper and a transparent polytetrafluoroethylene capillary tube embedded in the spiral channel fabricated on the copper. On this device, the P35S and Tnos sequences were successfully amplified within 9min, and the limit of detection of the DNA sample was estimated to be 0.005 ng microl(-1). Furthermore, a duplex continuous-flow PCR was also reported for the detection of the P35S and Tnos sequences in GMOs simultaneously. This method was coupled with the intercalating dye SYBR Green I and the melting curve analysis of the amplified products. Using this method, temperature differences were identified by the specific melting temperature values of two sequences, and the limit of detection of the DNA sample was assessed to be 0.01 ng microl(-1). Therefore, our results demonstrated that the continuous-flow PCR assay could discriminate the GMOs in a cost-saving and less time-consuming way.

  5. Endovascular balloon-assisted embolization of high-flow peripheral vascular lesions using dual-lumen coaxial balloon microcatheter and Onyx: initial experience.

    PubMed

    Jagadeesan, Bharathi D; Mortazavi, Shabnam; Hunter, David W; Duran-Castro, Olga L; Snyder, Gregory B; Siedel, Glen F; Golzarian, Jafar

    2014-04-01

    Balloon-assisted embolization performed by delivering Onyx ethylene vinyl alcohol copolymer through a dual-lumen coaxial balloon microcatheter is a new technique for the management of peripheral vascular lesions. This technique does not require an initial reflux of Onyx to form around the tip of the microcatheter before antegrade flow of Onyx can commence. In a series of four patients who were treated with the use of this technique, the absence of significant reflux of Onyx was noted, as were excellent navigability and easy retrieval of the balloon microcatheter. However, in one patient, there was inadvertent adverse embolization of a digital artery, which was not caused by reflux of Onyx but could still be related to balloon inflation.

  6. Preserved Collateral Blood Flow in the Endovascular M2CAO Model Allows for Clinically Relevant Profiling of Injury Progression in Acute Ischemic Stroke

    PubMed Central

    Little, Philip; Kvist, Ola; Grankvist, Rikard; Jonsson, Stefan; Damberg, Peter; Söderman, Michael; Arnberg, Fabian; Holmin, Staffan

    2017-01-01

    Interventional treatment regimens have increased the demand for accurate understanding of the progression of injury in acute ischemic stroke. However, conventional animal models severely inhibit collateral blood flow and mimic the malignant infarction profile not suitable for treatment. The aim of this study was to provide a clinically relevant profile of the emergence and course of ischemic injury in cases suitable for acute intervention, and was achieved by employing a M2 occlusion model (M2CAO) that more accurately simulates middle cerebral artery (MCA) occlusion in humans. Twenty-five Sprague-Dawley rats were subjected to Short (90 min), Intermediate (180 min) or Extended (600 min) transient M2CAO and examined longitudinally with interleaved diffusion-, T2- and arterial spin labeling perfusion-weighted magnetic resonance imaging before and after reperfusion. We identified a rapid emergence of cytotoxic edema within tissue regions undergoing infarction, progressing in several distinct phases in the form of subsequent moderation and then reversal at 230 min (p < 0.0001). We identified also the early emergence of vasogenic edema, which increased consistently before and after reperfusion (p < 0.0001). The perfusion of the penumbra correlated more strongly to the perfusion of adjacent tissue regions than did the perfusion of regions undergoing infarction (p = 0.0088). This was interpreted as an effect of preserved collateral blood flow during M2CAO. Accordingly, we observed only limited recruitment of penumbra regions to the infarction core. However, a gradual increase in infarction size was still occurring as late as 10 hours after M2CAO. Our results indicate that patients suffering MCA branch occlusion stand to benefit from interventional therapy for an extended time period after the emergence of ischemic injury. PMID:28068417

  7. Custom Fenestration Templates for Endovascular Repair of Juxtarenal Aortic Aneurysms

    PubMed Central

    Leotta, Daniel F.; Starnes, Benjamin W.

    2015-01-01

    Physician-modified endovascular grafts, with fenestrations added to accommodate major branch vessels, provide a means for endovascular treatment of abdominal aortic aneurysms that are adjacent to the renal arteries. Manual measurements of vessel origin locations from CT images, however, take time and can lead to errors in the positions of the fenestrations. To make the fenestration process faster and more accurate, we have developed a procedure to create custom templates that serve as patient-specific guides for graft fenestration. We use a 3D printer to create a clear rigid sleeve that replicates the patient’s aorta and includes holes placed precisely at the locations of the branch vessels. The sleeve is slipped over the graft, the locations of the openings are marked with a pen, and the fenestrations are created after removing the sleeve. Custom fenestration templates can potentially save procedural costs and make minimally-invasive aortic aneurysm repair available to more patients. PMID:25864045

  8. Custom fenestration templates for endovascular repair of juxtarenal aortic aneurysms.

    PubMed

    Leotta, Daniel F; Starnes, Benjamin W

    2015-06-01

    Physician-modified endovascular grafts, with fenestrations added to accommodate major branch vessels, provide a means for endovascular treatment of abdominal aortic aneurysms that are adjacent to the renal arteries. Manual measurements of vessel origin locations from computed tomography images, however, take time and can lead to errors in the positions of the fenestrations. To make the fenestration process faster and more accurate, we have developed a procedure to create custom templates that serve as patient-specific guides for graft fenestration. We use a three-dimensional printer to create a clear rigid sleeve that replicates the patient's aorta and includes holes placed precisely at the locations of the branch vessels. The sleeve is slipped over the graft, the locations of the openings are marked with a pen, and the fenestrations are created after the sleeve is removed. Custom fenestration templates can potentially save procedural costs and make minimally invasive aortic aneurysm repair available to more patients.

  9. Flow injection amperometric detection of insulin at cobalt hydroxide nanoparticles modified carbon ceramic electrode.

    PubMed

    Habibi, Esmaeil; Omidinia, Eskandar; Heidari, Hassan; Fazli, Maryam

    2016-02-15

    Cobalt hydroxide nanoparticles were prepared onto a carbon ceramic electrode (CHN|CCE) using the cyclic voltammetry (CV) technique. The modified electrode was characterized by X-ray diffraction and scanning electron microscopy. The results showed that CHN with a single-layer structure was uniformly electrodeposited on the surface of CCE. The electrocatalytic activity of the modified electrode toward the oxidation of insulin was studied by CV. CHN|CCE was also used in a homemade flow injection analysis system for insulin determination. The limit of detection (signal/noise [S/N] = 3) and sensitivity were found to be 0.11 nM and 11.8 nA/nM, respectively. Moreover, the sensor was used for detection of insulin in human serum samples. This sensor showed attractive properties such as high stability, reproducibility, and high selectivity.

  10. Assessment of endovascular coil configuration for embolization of intracranial aneurysms using computational fluid dynamics.

    PubMed

    Ohshima, Tomotaka; Miyachi, Shigeru; Takahashi, Ichiro; Ishii, Katsuya

    2015-08-01

    Endovascular coil embolization of arterial aneurysms is often complicated by reduced blood flow to branching arteries. To determine the optimal coil configuration for safe embolization of endovascular aneurysms without compromising blood flow in branching arteries. A 3-dimensional voxel model, built based on an unruptured vertebral artery-posterior inferior cerebellar artery (VA-PICA) aneurysm, predicted to show impairment of flow in the PICA during endovascular coil embolization (Case 0). Six different models of final coil configuration were generated and applied to this aneurysm. Case 1 was a round coil mass. Case 2 was designed with a stent assist. Cases 3, and 4 were designed with a neck remnant and Cases 5 and 6 incorporated a balloon neck remodeling technique. Computational fluid dynamics was used to analyze the flow in the PICA in each model. The average outflow to the PICA was highest in Case 0 and lowest in Case 2 (in descending order, Case 0, 5, 4, 6, 1, 3, and 2). There was better preservation of outflow to the PICA in the balloon neck remodeling models than in the neck remnant models. In a model of endovascular coil embolization, we found considerable differences in outflow to the branching artery with small changes in coil configuration. Careful preoperative planning is important to minimize the risk of thromboembolic events during and after endovascular coil embolization.

  11. Delayed pan-hypopituitarism as a complication following endovascular treatment of bilateral internal carotid artery aneurysms. A case report and review.

    PubMed

    Hall, Jonathan; Caputo, Carmela; Chung, Carlos; Holt, Michael; Wang, Yi Yuen

    2015-04-01

    Pan-hypopituitarism has been reported in patients who are subsequently found to have a cerebral aneurysm and there have been reports of pituitary dysfunction immediately following both surgical and endovascular treatment. The authors report a rare case of delayed pan-hypopituitarism following endovascular treatment of bilateral internal carotid artery aneurysms with coil embolisation and flow-diverting stents.

  12. Pulsatile flow of blood using a modified second-grade fluid model

    SciTech Connect

    Massoudi, Mehrdad; Tran, P.X.

    2008-07-01

    We study the unsteady pulsatile flow of blood in an artery, where the effects of body acceleration are included. The blood is modeled as a modified second-grade fluid where the viscosity and the normal stress coefficients depend on the shear rate. It is assumed that the blood near the wall behaves as a Newtonian fluid, and in the core as a non-Newtonian fluid. This phenomenon is also known as the Fahraeus–Lindqvist effect. The equations are made dimensionless and solved numerically.

  13. On a Modified Form of Navier-Stokes Equations for Three-Dimensional Flows

    PubMed Central

    Venetis, J.

    2015-01-01

    A rephrased form of Navier-Stokes equations is performed for incompressible, three-dimensional, unsteady flows according to Eulerian formalism for the fluid motion. In particular, we propose a geometrical method for the elimination of the nonlinear terms of these fundamental equations, which are expressed in true vector form, and finally arrive at an equivalent system of three semilinear first order PDEs, which hold for a three-dimensional rectangular Cartesian coordinate system. Next, we present the related variational formulation of these modified equations as well as a general type of weak solutions which mainly concern Sobolev spaces. PMID:25918743

  14. On a modified form of navier-stokes equations for three-dimensional flows.

    PubMed

    Venetis, J

    2015-01-01

    A rephrased form of Navier-Stokes equations is performed for incompressible, three-dimensional, unsteady flows according to Eulerian formalism for the fluid motion. In particular, we propose a geometrical method for the elimination of the nonlinear terms of these fundamental equations, which are expressed in true vector form, and finally arrive at an equivalent system of three semilinear first order PDEs, which hold for a three-dimensional rectangular Cartesian coordinate system. Next, we present the related variational formulation of these modified equations as well as a general type of weak solutions which mainly concern Sobolev spaces.

  15. Hypersensitivity reactions associated with endovascular devices.

    PubMed

    Honari, Golara; Ellis, Stephen G; Wilkoff, Bruce L; Aronica, Mark A; Svensson, Lars G; Taylor, James S

    2008-07-01

    Allergic reactions to endoprostheses are uncommon and reported in association with orthopaedic, dental, endovascular and other implanted devices. Hypersensitivity reactions to the biomaterials used in endovascular prostheses are among the infrequent reactions that may lead to local or systemic complications following cardiovascular therapeutic interventions. This article reviews potential immunotoxic effects of commonly used biomaterials. Reports of putative hypersensitivity reactions to endovascular devices, including coronary stents, perforated foramen occluders, pacemakers and implantable cardioverter defibrillators are also reviewed.

  16. Flow injection catalase activity measurement based on gold nanoparticles/carbon nanotubes modified glassy carbon electrode.

    PubMed

    El Nashar, Rasha Mohamed

    2012-07-15

    Amperometric flow injection method of hydrogen peroxide analysis was developed based on catalase enzyme (CAT) immobilization on a glassy carbon electrode (GC) modified with electrochemically deposited gold nanoparticles on a multiwalled carbon nanotubes/chitosan film. The resulting biosensor was applied to detect hydrogen peroxide with a linear response range 1.0×10(-7)-2.5×10(-3)M with a correlation coefficient 0.998 and response time less than 10s. The optimum conditions of film deposition such as potential applied, deposition time and pH were tested and the flow injection conditions were optimized to be: flow rate of 3ml/min, sample volume 75μl and saline phosphate buffer of pH 6.89. Catalase enzyme activity was successfully determined in liver homogenate samples of rats, raised under controlled dietary plan, using a flow injection analysis system involving the developed biosensor simultaneously with spectrophotometric detection, which is the common method of enzymatic assay. Copyright © 2011. Published by Elsevier B.V.

  17. Continuous 'Passive' flow-proportional monitoring of drainage using a new modified Sutro weir (MSW) unit.

    PubMed

    Vendelboe, Anders Lindblad; Rozemeijer, Joachim; de Jonge, Lis Wollesen; de Jonge, Hubert

    2016-03-01

    In view of their crucial role in water and solute transport, enhanced monitoring of agricultural subsurface drain tile systems is important for adequate water quality management. However, existing monitoring techniques for flow and contaminant loads from tile drains are expensive and labour intensive. The aim of this study was to develop a cost-effective and simple method for monitoring loads from tile drains. The Flowcap is a modified Sutro weir (MSW) unit that can be attached to the outlet of tile drains. It is capable of registering total flow, contaminant loads and flow-averaged concentrations. The MSW builds on a modern passive sampling technique that responds to hydraulic pressure and measures average concentrations over time (days to months) for various substances. Mounting the samplers in the MSW allowed a flow-proportional part of the drainage to be sampled. Laboratory testing yielded high linear correlation between the accumulated sampler flow, q total, and accumulated drainage flow, Q total (r (2) > 0.96). The slope of these correlations was used to calculate the total drainage discharge from the sampled volume, and therefore contaminant load. A calibration of the MSW under controlled laboratory condition was needed before interpretation of the monitoring results was possible. The MSW does not require a shed, electricity, or maintenance. This enables large-scale monitoring of contaminant loads via tile drains, which can improve contaminant transport models and yield valuable information for the selection and evaluation of mitigation options to improve water quality. Results from this type of monitoring can provide data for the evaluation and optimisation of best management practices in agriculture in order to produce the highest yield without water quality and recipient surface waters being compromised.

  18. Modified kinetic theory applied to the shear flows of granular materials

    NASA Astrophysics Data System (ADS)

    Duan, Yifei; Feng, Zhi-Gang; Michaelides, Efstathios E.; Mao, Shaolin

    2017-04-01

    Granular materials are characterized by large collections of discrete particles, where the particle-particle interactions are significantly more important than the particle-fluid interactions. The current kinetic theory captures fairly accurately the granular flow behavior in the dilute case, when only binary interactions are significant, but is not accurate at all in the dense flow regime, where multi-particle interactions and contacts must be modeled. To improve the kinetic theory results for granular flows in the dense flow regime, we propose a Modified Kinetic Theory (MKT) model that utilizes the contact duration or cutoff time to account for the complex particle-particle interactions in the dense regime. The contact duration model, also called TC model, was originally proposed by Luding and McNamara ["How to handle the inelastic collapse of a dissipative hard-sphere gas with the TC model," Granular Matter 1, 113 (1998)] to solve the inelastic collapse issue existing in the inelastic hard sphere model. This model defines a cutoff time tc such that dissipation is not counted if the time between two consecutive contacts is less than tc. As shown in their study, the use of a cutoff time tc can also reduce the dissipation during multi-particle contacts. In this paper we relate the TC model with the Discrete Element Method (DEM) by choosing the cutoff time tc to be the duration of contact calculated from the linear-spring-dashpot soft-sphere model of the DEM. We examine two types of granular flows, simple shear flow and the plane shear flow, and compare the results of the classical kinetic theory model, the present MKT model, and the DEM model. We show that the MKT model entails a significant improvement over the kinetic theory model for simple shear flows at inertial regimes. With the MKT model the calculations are close to the DEM results at solid fractions as high as 0.57. Even for the plane shear flows, where shear rate and solid fraction are inhomogeneous, the

  19. Modified kinetic theory applied to the shear flows of granular materials

    DOE PAGES

    Duan, Yifei; Feng, Zhi -Gang; Michaelides, Efstathios E.; ...

    2017-04-11

    Here, granular materials are characterized by large collections of discrete particles, where the particle-particle interactions are significantly more important than the particle-fluid interactions. The current kinetic theory captures fairly accurately the granular flow behavior in the dilute case, when only binary interactions are significant, but is not accurate at all in the dense flow regime, where multi-particle interactions and contacts must be modeled. To improve the kinetic theory results for granular flows in the dense flow regime, we propose a Modified Kinetic Theory (MKT) model that utilizes the contact duration or cut-off time to account for the complex particle-particle interactionsmore » in the dense regime. The contact duration model, also called TC model, is originally proposed by Luding and McNamara to solve the inelastic collapse issue existing in the Inelastic Hard Sphere (IHS) model. This model defines a cut-off time tc such that dissipation is not counted if the time between two consecutive contacts is less than tc. As shown in their study, the use of a cut-off time tc can also reduce the dissipation during multi-particle contacts. In this paper we relate the TC model with the Discrete Element Method (DEM) by choosing the cut-off time tc to be the duration of contact calculated from the linear-spring-dashpot soft-sphere model of the DEM. We examine two types of granular flows: simple shear flow and the plane shear flow, and compare the results of the classical Kinetic Theory (KT) model, the present MKT model, and the DEM model. Here, we show that the MKT model entails a significant improvement over the KT model for simple shear flows at inertial regimes. With the MKT model the calculations are close to the DEM results at solid fractions as high as 0.57. Even for the plane shear flows, where shear rate and solid fraction are inhomogeneous, the results of the MKT model agree very well with the DEM results.« less

  20. A modified restricted Euler equation for turbulent flows with mean velocity gradients

    NASA Technical Reports Server (NTRS)

    Girimaji, Sharath S.; Speziale, Charles G.

    1994-01-01

    The restricted Euler equation captures many important features of the behavior of the velocity gradient tensor observed in direct numerical simulations (DNS) of isotropic turbulence. However, in slightly more complex flows the agreement is not good, especially in regions of low dissipation. In this paper, it is demonstrated that the Reynolds-averaged restricted Euler equation violates the balance of mean momentum for virtually all homogeneous turbulent flows with only two major exceptions: isotropic and homogeneously-sheared turbulence. A new model equation which overcomes this shortcoming and is more widely applicable is suggested. This modele is derived from the Navier-Stokes equation with a restricted Euler type approximation made on the fluctuating velocity gradient field. Analytical solutions of the proposed modified restricted Euler equation appear to be difficult to obtain. Hence, a strategy for numerically calculating the velocity gradient tensor is developed. Preliminary calculations tend to indicate that the modified restricted Euler equation captures many important aspects of the behavior of the fluctuating velocity gradients in anisotropic homogeneous turbulence.

  1. METHODS FOR DETERMINING EXPOSURE TO AND POTENTIAL ECOLOGICAL EFFECTS OF GENE FLOW FROM GENETICALLY MODIFIED CROPS TO COMPATIBLE RELATIVES

    EPA Science Inventory

    SCIENCE QUESTIONS:

    -Does gene flow occur from genetically modified (GM) crop plants to compatible plants?

    -How can it be measured?

    -Are there ecological consequences of GM crop gene flow to plant communities?



    RESEARCH:

    The objectives ...

  2. METHODS FOR DETERMINING EXPOSURE TO AND POTENTIAL ECOLOGICAL EFFECTS OF GENE FLOW FROM GENETICALLY MODIFIED CROPS TO COMPATIBLE RELATIVES

    EPA Science Inventory

    SCIENCE QUESTIONS:

    -Does gene flow occur from genetically modified (GM) crop plants to compatible plants?

    -How can it be measured?

    -Are there ecological consequences of GM crop gene flow to plant communities?



    RESEARCH:

    The objectives ...

  3. Effects of modified pharmacologic stress approaches on hyperemic myocardial blood flow

    SciTech Connect

    Czernin, J.; Auerbach, M.; Sun, K.T.

    1995-04-01

    Pharmacologic stress testing with 0.56 mg/kg of intravenous dipyridamole is frequently used to noninvasively detect coronary artery disease (CAD). However, high-dose dipyridamole (0.80 mg/kg) or the combination of standard-dose dipyridamole (0.56 mg/kg) with the isometric handgrip maneuver might evoke a greater coronary hyperemic response. To evaluate the effect of modified pharmacologic stress tests, myocardial blood flow was quantified in 11 male subjects (mean age: 27 {plus_minus} 7 yr) during standard-dose dipyridamole (0.56 mg/kg), high-dose dipyridamole (0.80 mg/kg) and standard-dose dipyridamole combined with the isometric handgrip exercise using dynamic PET and a two-compartment model for {sup 13}N-ammonia. Systolic blood pressure, heart rate and rate pressure product remained unchanged from standard to high-dose dipyridamole but increased with the addition of the isometric handgrip. Myocardial blood flow was unchanged from standard to high-dose dipyridamole but was lower with the addition of the isometric handgrip. The hyperemic response induced by standard-dose dipyridamole cannot be further enhanced by high-dose dipyridamole. The addition of the isometric handgrip exercise results in a modest, but significant decline in hyperemic blood flow possibly due to increased extravascular resistive forces or an increase in a mediated coronary vasoconstriction associated with exercise. 31 refs., 2 figs., 1 tab.

  4. Study on the flow characteristics and the wastewater treatment performance in modified internal circulation reactor.

    PubMed

    Wang, Jiade; Xu, Weijun; Yan, Jingjia; Yu, Jianming

    2014-12-01

    A modified internal circulation (MIC) reactor with an external circulation system was proposed and the performance of treating dyeing wastewater using both MIC and typical IC reactor were compared. Utilization of the external circulation system in the MIC reactor could dramatically improve the mixing intensity of the biomass with the wastewater and resulted in better performance. The COD removal efficiency, biogas production, volatile fatty acids and effluent color were approximately 87%, 98 L d−1, 180 mg L−1 and 100 times, respectively, in the MIC reactor with a hydraulic retention time of 5 h and organic loading rate of 15 kg COD m−3 d−1. The hydrodynamics of the MIC reactor under different flows rate of external circulation were also analyzed using computational fluid dynamics (CFD) method. The optimal flow rate of external circulation was 12 L min−1, which resulted in a corresponding up-flow velocity of 40 m h−1. The consistency of the result between experiment and simulation validated the scientificity of CFD technique applied to numerical simulation of the MIC reactor.

  5. A modified flow/field model of the solar wind interaction with Mars

    SciTech Connect

    Stewart, B.K.

    1992-01-01

    A modified steady state flow/field model is applied to the direct interaction of the solar wind with the Martian ionosphere. The original flow/field model (Cloutier et al., 1987) is a one-dimensional, self-consistent derivation of differentials in vertical velocity, magnetic field, and ion densities from the coupled MHD equations. While successful in reproducing features of the ionosphere of Venus (Cloutier et al., 1987; McGary 1987) and of Mars (Stewart, 1989), the flow/field model required an independently specified heating term (Q). The requirement of this term implies the presence of an energy source not accounted for in conventional calculations. This source was previously simulated with the inclusion of Q, but an unrecognized momentum or pressure term the inclusion of Q, but an unrecognized momentum or pressure term may also provide the coupling with the solar wind without the need of the free parameter Q. An in-depth analysis of Pioneer Venus data in relation to the total conservation of momentum of the system led to the discovery that the total momentum was in most cases not entirely accounted for, and that this [open quotes]missing[close quotes] term was correlated with solar wind dynamic pressure. By including this missing pressure, a new set of differential equations, which were also extended to include horizontal velocity terms, was derived. Extrapolation of the missing pressure to Mars gave results that faithfully reproduced the ionospheric features associated with previous flow/field models while maintaining agreement with Viking 1 and 2 observations. Finally, the author suggests that the source of P[sub missing] could be a population of suprathermal particles within the ionosphere. The missing pressures in the Viking simulations are consistent with measured suprathermal pressures at Mars (Hanson and Mantas, 1988).

  6. Flow and heat transfer to modified second grade fluid over a non-linear stretching sheet

    NASA Astrophysics Data System (ADS)

    Khan, Masood; Rahman, Masood ur

    2015-08-01

    The objective of the present work is to analyze the two-dimensional boundary layer flow and heat transfer of a modified second grade fluid over a non-linear stretching sheet of constant surface temperature. The modelled momentum and energy equations are deduced to a system of ordinary differential equations by employing suitable transformations in boundary layer region and integrated numerically by fourth and fifth order Runge-Kutta Fehlberg method. Additionally, the analytic solutions of the governing problem are presented for some special cases. The secured results make it clear that the power-law index reduces both the momentum and thermal boundary layers. While the incremented values of the generalized second grade parameter leads to an increase in the momentum boundary layer and a decrease in the thermal boundary layer. To see the validity of the present results we have made a comparison with the previously published results as a special case with an outstanding compatibility.

  7. Flow Injection Analysis of 5-(Hydroxymethyl)-2-furaldehyde in Honey by a Modified Winkler Method.

    PubMed

    Castoldi, Karine; Milani, Maria Izabel; Rossini, Eduardo L; Pezza, Leonardo; Pezza, Helena R

    2016-01-01

    One of the quality indicators for honey is 5-(hydroxymethyl)-2-furaldehyde (HMF), which is formed during the heating or aging of honey. The International Honey Commission recommends three methods for the determination of HMF in honey: the Winkler method, the White method, and determination by HPLC. The Winkler method uses the carcinogenic substance p-toluidine, which is not in accordance with the principles of Green Chemistry. The present work describes the determination of HMF in honey by flow injection analysis (FIA) using a modified Winkler method, replacing p-toluidine with p-aminobenzoic acid. The linear range was 1.00 to 40.0 mg L(-1), the limit of detection (LOD) was 0.43 mg L(-1), and the limit of quantification (LOQ) was 1.32 mg L(-1). The method is an efficient and environmentally friendly technique for the analysis of HMF in honey.

  8. Stability analysis of Boundary Layer in Poiseuille Flow through a modified Orr-Sommerfeld equation

    NASA Astrophysics Data System (ADS)

    Chabi Orou, Jean Bio; Monwanou, Vincent; Miwadinou, Clément

    2012-11-01

    For applications regarding transition prediction, wing design and control of boundary layers, the fundamental understanding of disturbance growth in the flat plate boundary layer is an important issue. In the present work we investigate the stability of boundary layer in Poiseuille flow. We normalize pressure and time by inertial and viscous effect. The disturbances are taken to be periodic in the spanwise direction and time. We present a set of linear governing equations for the parabolic evolution of wavelike disturbances. Then, we derive modified Orr-Sommerfeld equations that can be applied in the layer. We find that Squire's theorem is applicable for the boundary layer. We find also that normalization by inertial or viscous effects leads to the same stability or instability. We find through the graphs that transition from stability to instability or the opposite can occur according to the Reynolds number and the wave number.

  9. Velocity measurements of the liquid - gas flow using gamma absorption and modified conditional averaging

    NASA Astrophysics Data System (ADS)

    Hanus, Robert; Zych, Marcin; Kowalczyk, Adam; Petryka, Leszek

    2015-05-01

    The paper presents idea and an exemplary application of gamma-absorption in the measurement of gas bubbles transportation in a gas-liquid mixture flow through a horizontal pipeline. In the tests on laboratory installation two 241Am radioactive sources and probes with NaI(Tl) scintillation crystals have been used. For analysis of electrical signals obtained from detectors the modified conditional averaging of the absolute value of delayed signal (CAAV) is proposed. The proposed method is based on the quotient of classical cross-correlation (CCF) and CAAV. Results of the time delay estimation and gas-phase velocity measurements are compared with one obtained using CCF. The combined uncertainties of the mean velocity of air bubbles evaluation in the presented experiment did not exceed 2.1% (CCF) and 1.7% (CCF/CAAV), which is a satisfactory result in industrial applications.

  10. Graphite felt modified with bismuth nanoparticles as negative electrode in a vanadium redox flow battery.

    PubMed

    Suárez, David J; González, Zoraida; Blanco, Clara; Granda, Marcos; Menéndez, Rosa; Santamaría, Ricardo

    2014-03-01

    A graphite felt decorated with bismuth nanoparticles was studied as negative electrode in a vanadium redox flow battery (VRFB). The results confirm the excellent electrochemical performance of the bismuth modified electrode in terms of the reversibility of the V(3+) /V(2+) redox reactions and its long-term cycling performance. Moreover a mechanism that explains the role that Bi nanoparticles play in the redox reactions in this negative half-cell is proposed. Bi nanoparticles favor the formation of BiHx , an intermediate that reduces V(3+) to V(2+) and, therefore, inhibits the competitive irreversible reaction of hydrogen formation (responsible for the commonly observed loss of Coulombic efficiency of VRFBs). Thus, the total charge consumed during the cathodic sweep in this electrode is used to reduce V(3+) to V(2+) , resulting in a highly reversible and efficient process.

  11. Effects of Workflow Optimization in Endovascularly Treated Stroke Patients – A Pre-Post Effectiveness Study

    PubMed Central

    Behme, Daniel; Tsogkas, Ioannis; Knauth, Michael; Maier, Ilko; Karch, André; Mikolajczyk, Rafael; Hinz, José; Liman, Jan; Psychogios, Marios-Nikos

    2016-01-01

    Endovascular treatment of acute ischemic stroke has become standard of care for patients with large artery occlusion. Early restoration of blood flow is crucial for a good clinical outcome. We introduced an interdisciplinary standard operating procedure (SOP) between neuroradiologists, neurologists and anesthesiologists in order to streamline patient management. This study analyzes the effect of optimized workflow on periprocedural timings and its potential influence on clinical outcome. Data were extracted from a prospectively maintained university hospital stroke database. The standard operating procedure was established in February 2014. Of the 368 acute stroke patients undergoing endovascular treatment between 2008 and 2015, 278 patients were treated prior to and 90 after process optimization. Outcome measures were periprocedural time intervals and residual functional impairment. After implementation of the SOP, time from symptom onset to reperfusion was significantly reduced (median 264 min prior and 211 min after SOP-introduction (IQR 228–32 min and 161–278 min, respectively); P<0.001). Especially faster supply of imaging and prompt transfer of patients to the angiography suite contributed to this effect. Time between hospital admission and groin puncture was reduced by half after process optimization (median 64 min after versus 121 min prior to SOP-introduction (IQR 54–77 min and 96–161 min, respectively); P<0.001). Clinical outcome was significantly better after workflow optimization as measured with the modified Rankin Scale (common odds ratio (OR) 0.56; 95% CI 0.32–0.98; P = 0.038). Optimization of workflow and interdisciplinary teamwork significantly improved the outcome of patients with acute ischemic stroke due to a significant reduction of in-hospital examination, transportation, imaging and treatment times. PMID:28036401

  12. Other endovascular methods of treating the diabetic foot.

    PubMed

    Peeters, P; Keirse, K; Verbist, J; Deloose, K; Bosiers, M

    2009-06-01

    Critical limb ischemia (CLI) is an endstage manifestation of peripheral artery disease (PAD) and typically describes patients with ischemic rest pain (Rutherford Category 4), or patients with ischemic skin lesions, either ulcers or gangrene (Rutherford Category 5-6). CLI due to infrapopliteal lesions is often not a good indication for infrageniculate bypass surgery placement, due to the presence of prohibitive comorbidities, inadequate conduit, and lack of suitable distal targets for revascularization. Therefore, CLI patients due to blockage of below-the-knee arteries are in benefit of the endovascular approach. Infrapopliteal PTA became feasible with the introduction of low-profile peripheral balloon systems and the use of coronary balloons. Stent implantation, however, is generally reserved for cases with a suboptimal outcome after PTA (i.e. >50% residual stenosis, flow-limiting dissection). Because of the fear that early thrombosis and late luminal loss due to intimal hyperplasia formation will potentially lead to insufficient long-term patency rates, efforts to extend the range of endovascular approaches to CLI are presently focused on. Cryoplasty, scoring balloon angioplasty, excimer laser therapy and atherectomy using different types of atherectomy devices have been introduced. The current article provides an overview of the endovascular treatment strategies for infrapopliteal lesions in patients with CLI.

  13. Group Invariance Properties of the Inviscid Compressible Flow Equations for a Modified Tait Equation of State

    NASA Astrophysics Data System (ADS)

    Ramsey, Scott; Baty, Roy

    2015-11-01

    This work considers the group invariance properties of the inviscid compressible flow equations (Euler equations) under the assumptions of one-dimensional symmetry and a modified Tait equation of state (EOS) closure model. When written in terms of an adiabatic bulk modulus, a transformed version of these equations is found to be identical to that for an ideal gas EOS. As a result, the Lie group invariance structure of these equations - and their subsequent reduction to a lower-order system - is identical to the published results for the ideal gas case. Following the reduction of the Euler equations to a system of ordinary differential equations, a variety of elementary closed-form solutions are derived. These solutions are then used in conjunction with the Rankine-Hugoniot conditions to construct discontinuous shock wave and free surface solutions that are analogous to the classical Noh, Sedov, Guderley, and Hunter similarity solutions of the Euler equations for an ideal gas EOS. The versions of these problems for the modified Tait EOS are found to be semi-analytic in that a transcendental root extraction (and in some cases numerical integration of ordinary differential equations) enables solution of the relevant equations.

  14. Flow injection amperometric sensor with a carbon nanotube modified screen printed electrode for determination of hydroquinone.

    PubMed

    Upan, Jantima; Reanpang, Preeyaporn; Chailapakul, Orawon; Jakmunee, Jaroon

    2016-01-01

    Flow injection amperometric (FI-Amp) sensor was developed for sensitive and selective determination of hydroquinone. A simple screen printed carbon electrode (SPCE) was modified with various nanomaterials for improvement of sensitivity on the determination of quinone. As a result, the appropriate sensitivity is obtained from the SPCE modified with carbon nanotube (CNT) which indicated that CNT contributed to the transfer of electron to quinone. The reproducibility (n=9) and repeatability (n=111) of SPCE-CNT were obtained at 4.4% and 3.6%RSD, respectively. The SPCE-CNT electrode and enzymatic column were incorporated to the FI-Amp system to determine hydroquinone. Laccase was immobilized on silica gel using a cross-linking method by glutaraldehyde modification and then packed in the column. The laccase column has high efficiency for catalytic oxidation of hydroquinone to quinone, which further detects by amperometric detection. Parameters affecting response of the proposed sensor, i.e., pH, ionic strength, and temperature have been optimized. The proposed system provided a wide linear range between 1 and 50 µM with detection limit of 0.1 µM. Satisfactory recoveries in the range of 91.2-103.8% were obtained for the analysis of water sample.

  15. An overview of thin film nitinol endovascular devices.

    PubMed

    Shayan, Mahdis; Chun, Youngjae

    2015-07-01

    Thin film nitinol has unique mechanical properties (e.g., superelasticity), excellent biocompatibility, and ultra-smooth surface, as well as shape memory behavior. All these features along with its low-profile physical dimension (i.e., a few micrometers thick) make this material an ideal candidate in developing low-profile medical devices (e.g., endovascular devices). Thin film nitinol-based devices can be collapsed and inserted in remarkably smaller diameter catheters for a wide range of catheter-based procedures; therefore, it can be easily delivered through highly tortuous or narrow vascular system. A high-quality thin film nitinol can be fabricated by vacuum sputter deposition technique. Micromachining techniques were used to create micro patterns on the thin film nitinol to provide fenestrations for nutrition and oxygen transport and to increase the device's flexibility for the devices used as thin film nitinol covered stent. In addition, a new surface treatment method has been developed for improving the hemocompatibility of thin film nitinol when it is used as a graft material in endovascular devices. Both in vitro and in vivo test data demonstrated a superior hemocompatibility of the thin film nitinol when compared with commercially available endovascular graft materials such as ePTFE or Dacron polyester. Promising features like these have motivated the development of thin film nitinol as a novel biomaterial for creating endovascular devices such as stent grafts, neurovascular flow diverters, and heart valves. This review focuses on thin film nitinol fabrication processes, mechanical and biological properties of the material, as well as current and potential thin film nitinol medical applications.

  16. Active flow control insight gained from a modified integral boundary layer equation

    NASA Astrophysics Data System (ADS)

    Seifert, Avraham

    2016-11-01

    Active Flow Control (AFC) can alter the development of boundary layers with applications (e.g., reducing drag by separation delay or separating the boundary layers and enhancing vortex shedding to increase drag). Historically, significant effects of steady AFC methods were observed. Unsteady actuation is significantly more efficient than steady. Full-scale AFC tests were conducted with varying levels of success. While clearly relevant to industry, AFC implementation relies on expert knowledge with proven intuition and or costly and lengthy computational efforts. This situation hinders the use of AFC while simple, quick and reliable design method is absent. An updated form of the unsteady integral boundary layer (UIBL) equations, that include AFC terms (unsteady wall transpiration and body forces) can be used to assist in AFC analysis and design. With these equations and given a family of suitable velocity profiles, the momentum thickness can be calculated and matched with an outer, potential flow solution in 2D and 3D manner to create an AFC design tool, parallel to proven tools for airfoil design. Limiting cases of the UIBL equation can be used to analyze candidate AFC concepts in terms of their capability to modify the boundary layers development and system performance.

  17. Determination of Mycotoxin Production of Fusarium Species in Genetically Modified Maize Varieties by Quantitative Flow Immunocytometry

    PubMed Central

    Bánáti, Hajnalka; Darvas, Béla; Fehér-Tóth, Szilvia; Czéh, Árpád; Székács, András

    2017-01-01

    Levels of mycotoxins produced by Fusarium species in genetically modified (GM) and near-isogenic maize, were determined using multi-analyte, microbead-based flow immunocytometry with fluorescence detection, for the parallel quantitative determination of fumonisin B1, deoxynivalenol, zearalenone, T-2, ochratoxin A, and aflatoxin B1. Maize varieties included the genetic events MON 810 and DAS-59122-7, and their isogenic counterparts. Cobs were artificially infested by F. verticillioides and F. proliferatum conidia, and contained F. graminearum and F. sporotrichoides natural infestation. The production of fumonisin B1 and deoxynivalenol was substantially affected in GM maize lines: F. verticillioides, with the addition of F. graminearum and F. sporotrichoides, produced significantly lower levels of fumonisin B1 (~300 mg·kg−1) in DAS-59122-7 than in its isogenic line (~580 mg·kg−1), while F. proliferatum, in addition to F. graminearum and F. sporotrichoides, produced significantly higher levels of deoxynivalenol (~18 mg·kg−1) in MON 810 than in its isogenic line (~5 mg·kg−1). Fusarium verticillioides, with F. graminearum and F. sporotrichoides, produced lower amounts of deoxynivalenol and zearalenone than F. proliferatum, with F. graminearum and F. sporotrichoides. T-2 toxin production remained unchanged when considering the maize variety. The results demonstrate the utility of the Fungi-Plex™ quantitative flow immunocytometry method, applied for the high throughput parallel determination of the target mycotoxins. PMID:28241411

  18. Endovascular Treatment of Nutcracker Syndrome.

    PubMed

    Policha, Aleksandra; Lamparello, Patrick; Sadek, Mikel; Berland, Todd; Maldonado, Thomas

    2016-10-01

    Nutcracker syndrome, or mesoaortic compression of the left renal vein (LRV), with associated symptoms related to venous hypertension in the left kidney, is a rare entity that may result in severe symptoms requiring operative intervention. We report on 3 patients who presented with nutcracker syndrome, including one patient with a circumaortic LRV resulting in posterior nutcracker syndrome, who underwent successful endovascular treatment with renal vein stenting. A review of existing literature on endovascular management of nutcracker syndrome follows. Three women (age range 28-43 years) presented with symptoms and imaging studies consistent with nutcracker syndrome. Symptoms included pelvic and flank pain in all 3 patients, and episodes of hematuria in 2 patients. Imaging studies demonstrated compression of the LRV between the superior mesenteric artery and aorta in 2 of the patients. The third patient was noted to have a circumaortic LRV. All 3 patients underwent venography and LRV stenting. Stents included a 12 × 40 mm self-expanding nitinol stent, 14 × 60 mm WALLSTENT, and 16 × 40 mm WALLSTENT. All patients were placed on clopidogrel postoperatively. The duration of follow-up ranged from 6 to 27 months. At follow-up, all 3 patients reported significant symptomatic improvement, and duplex ultrasonography demonstrated stent patency in all. Nutcracker syndrome is a rare condition that can be successfully treated with renal vein stenting via an endovascular approach. Results are encouraging at follow-up periods beyond 2 years. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Combined external counterpulsation and endovascular stenting treatment for symptomatic vertebrobasilar artery stenosis: two case reports.

    PubMed

    Xiong, Li; Chen, Xiang Yan; Leung, Thomas Wai Hong; Wong, Lawrence Ka Sing

    2015-10-01

    Symptomatic vertebrobasilar artery (VBA) stenosis has a poor prognosis. Intravascular stents provide a new therapeutic approach, but the long-term outcome of stenting compared with medical outcome is controversial. External counterpulsation (ECP) is a noninvasive method to improve perfusion of vital organs. We report two cases of this combination with ECP treatment in addition to receiving endovascular stenting. Two patients experienced posterior ischemic stroke. Digital subtraction angiography revealed a severe basilar or vertebral artery stenosis. Computed tomographic perfusion revealed significantly decreased perfusion of posterior artery territories. Both of them underwent combined ECP treatment and endovascular stenting of the stenosed basilar or vertebral artery, without recurrent stroke within 30 days after stenting. The two patients were independent (modified Rankin scale ≤2) at the 12-month follow-up time. Combined ECP treatment and endovascular stent placement may be effective and safe for patients with symptomatic VBA stenosis who failed aggressive medical treatment.

  20. Endovascular management of traumatic peripheral arterial injuries.

    PubMed

    Scott, Aaron R; Gilani, Ramyar; Tapia, Nicole M; Mattox, Kenneth L; Wall, Matthew J; Suliburk, James W

    2015-12-01

    Traumatic injuries to peripheral arterial vessels are increasingly managed with endovascular techniques. Early small series have suggested that endovascular therapy is feasible and decreases operative blood loss, but these data are limited. The purpose of this study was to evaluate the feasibility and outcomes of endovascular management of nonaortic arterial trauma. We reviewed records of traumatic nonaortic arterial injuries presenting at an urban level 1 trauma center from December 2009-July 2013. Patients undergoing treatment in interventional radiology and patients whose injuries occurred >72 h before presentation were excluded. Demographics, indicators of injury severity, operative blood loss, transfusion requirements, and clinical outcome were compared between patients undergoing endovascular and open management using appropriate inferential statistics. During the study period, 17 patients underwent endovascular interventions and 20 had open surgery. There were 19 upper extremity and/or thoracic outlet arterial injuries, 15 lower extremity injuries and 11 pelvic injuries. Endovascular cases were completed using a vascular imaging C-arm in a standard operating room. Estimated blood loss during the primary procedure was significantly lower with endovascular management (150 versus 825 cc, P < 0.001). No differences were observed between cohorts in age, injury severity score, intensive care unit length of stay, arterial pH, transfusion requirements, inpatient complication rate, or mortality. Our experience with endovascular management demonstrates its feasibility with commonly available tools. Operative blood loss may be significantly decreased using endovascular techniques. Further study is needed to refine patient selection criteria and to define long-term outcomes. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. Endovascular management of gastric varices.

    PubMed

    Saad, Wael E

    2014-11-01

    Bleeding from gastric varices is a major complication of portal hypertension. Although less common than bleeding associated with esophageal varices, gastric variceal bleeding has a higher mortality. From an endovascular perspective,transjugular intrahepatic portosystemic shunts (TIPS) to decompress the portal circulation and/or balloon-occluded retrograde transvenous obliteration (BRTO) are utilized to address bleeding gastric varices. Until recently, there was a clear medical cultural divide between the strategy of decompressing the portal circulation (TIPS creation, for example) and transvenous obliteration for the management of gastric varices. However, the practice of BRTO is gaining acceptance in the United States and its practice is spreading rapidly. Recently, the American College of Radiology has identified BRTO to be a viable alternative to TIPS in particular anatomical and clinical scenarios. However, the anatomical and clinical applications of BRTO were not defined beyond the conservative approach of resorting to BRTO in non-TIPS candidates. The article discusses the outcomes of BRTO and TIPS for the management of gastric varices individually or in combination. Definitions, endovascular technical concepts and contemporary vascular classifications of gastric variceal systems are described in order to help grasp the complexity of the hemodynamic pathology and hopefully help define the pathology better for future reporting and lay the ground for more defined stratification of patients not only based on comorbidity and hepatic reserve but on anatomy and hemodynamic classifications.

  2. Endovascular Therapy Is Effective and Safe for Patients With Severe Ischemic Stroke: Pooled Analysis of Interventional Management of Stroke III and Multicenter Randomized Clinical Trial of Endovascular Therapy for Acute Ischemic Stroke in the Netherlands Data.

    PubMed

    Broderick, Joseph P; Berkhemer, Olvert A; Palesch, Yuko Y; Dippel, Diederik W J; Foster, Lydia D; Roos, Yvo B W E M; van der Lugt, Aad; Tomsick, Thomas A; Majoie, Charles B L M; van Zwam, Wim H; Demchuk, Andrew M; van Oostenbrugge, Robert J; Khatri, Pooja; Lingsma, Hester F; Hill, Michael D; Roozenbeek, Bob; Jauch, Edward C; Jovin, Tudor G; Yan, Bernard; von Kummer, Rüdiger; Molina, Carlos A; Goyal, Mayank; Schonewille, Wouter J; Mazighi, Mikael; Engelter, Stefan T; Anderson, Craig S; Spilker, Judith; Carrozzella, Janice; Ryckborst, Karla J; Janis, L Scott; Simpson, Kit N

    2015-12-01

    We assessed the effect of endovascular treatment in acute ischemic stroke patients with severe neurological deficit (National Institutes of Health Stroke Scale score, ≥20) after a prespecified analysis plan. The pooled analysis of the Interventional Management of Stroke III (IMS III) and Multicenter Randomized Clinical Trial of Endovascular Therapy for Acute Ischemic Stroke in the Netherlands (MR CLEAN) trials included participants with an National Institutes of Health Stroke Scale score of ≥20 before intravenous tissue-type plasminogen activator (tPA) treatment (IMS III) or randomization (MR CLEAN) who were treated with intravenous tPA ≤3 hours of stroke onset. Our hypothesis was that participants with severe stroke randomized to endovascular therapy after intravenous tPA would have improved 90-day outcome (distribution of modified Rankin Scale scores), when compared with those who received intravenous tPA alone. Among 342 participants in the pooled analysis (194 from IMS III and 148 from MR CLEAN), an ordinal logistic regression model showed that the endovascular group had superior 90-day outcome compared with the intravenous tPA group (adjusted odds ratio, 1.78; 95% confidence interval, 1.20-2.66). In the logistic regression model of the dichotomous outcome (modified Rankin Scale score, 0-2, or functional independence), the endovascular group had superior outcomes (adjusted odds ratio, 1.97; 95% confidence interval, 1.09-3.56). Functional independence (modified Rankin Scale score, ≤2) at 90 days was 25% in the endovascular group when compared with 14% in the intravenous tPA group. Endovascular therapy after intravenous tPA within 3 hours of symptom onset improves functional outcome at 90 days after severe ischemic stroke. URL: http://www.clinicaltrials.gov. Unique identifier: NCT00359424 (IMS III) and ISRCTN10888758 (MR CLEAN). © 2015 American Heart Association, Inc.

  3. Endovascular treatment of acute ischemic stroke.

    PubMed

    Leslie-Mazwi, Thabele; Rabinov, James; Hirsch, Joshua A

    2016-01-01

    Endovascular thrombectomy is an effective treatment for major acute ischemic stroke syndromes caused by major anterior circulation artery occlusions (commonly referred to as large vessel occlusion) and is superior to intravenous thrombolysis and medical management. Treatment should occur as quickly as is reasonably possible. All patients with moderate to severe symptoms (National Institutes of Health stroke scale >8) and a treatable occlusion should be considered. The use of neuroimaging is critical to exclude hemorrhage and large ischemic cores. Very shortly after stroke onset (<3 hours) computed tomography (CT) and CT angiography provide sufficient information to proceed; diffusion magnetic resonance imaging (MRI) is less reliable during this early stage. After 3 hours from onset diffusion MRI is the most reliable method to define ischemic core size and should be used in centers that can offer it rapidly. Recanalization is highly effective with a stentriever or using a direct aspiration technique, with the patient awake or under conscious sedation rather than general anesthesia, if it may be performed safely. After thrombectomy the patient should be admitted to an intensive care setting and inpatient rehabilitation undertaken as soon as feasible. Patient outcomes should be assessed at 3 months, preferably using the modified Rankin score. © 2016 Elsevier B.V. All rights reserved.

  4. Endovascular Management of Posttraumatic Arteriovenous Fistulae

    SciTech Connect

    Koshy, Chiramel George Keshava, Shyamkumar Nigudala; Surendrababu, Narayanam R. S.; Moses, Vinu; Stephen, Edwin; Agarwal, Sunil

    2009-09-15

    Surgery is considered to be the treatment of choice for vascular injuries caused by trauma. However, endovascular techniques are emerging as an alternative means of treatment. In this article, we describe three patients with posttraumatic arteriovenous fistulae in different body regions that were managed using endovascular techniques. Each case had its unique set of associated problems requiring innovative methods and a multidisciplinary approach. While the short-term results are encouraging, long-term follow-up of posttraumatic arteriovenous fistulae that have been treated with endovascular techniques is still required.

  5. A modified Muskingum routing approach for floodplain flows: Theory and practice

    NASA Astrophysics Data System (ADS)

    O'Sullivan, J. J.; Ahilan, S.; Bruen, M.

    2012-11-01

    SummaryHydrological or hydraulic flood routing methods can be used to predict the floodplain influences on a flood wave as it passes along a river reach. While hydraulic routing uses both the equation of continuity and the equation of momentum to describe the dynamics of river flows, the simpler data requirements of hydrological routing makes it useful for preliminary estimates of the time and shape of a flood wave at successive points along a river. This paper presents a modified linear Muskingum hydrological routing method where the floodplain effects on flood peak attenuation and flood wave travel time are included in routing parameters. Developing the routing parameters initially involved routing hydrographs of different flood peak and duration through a 1-dimensional model of a generalised river reach in which a range of geometrical and resistance properties were varied. Comparison of upstream and simulated downstream hydrographs for each condition investigated, allowed the attenuation and travel time (storage constant, K, in standard Muskingum routing) of the flood wave to be estimated. Standard Muskingum routing was then used to develop downstream hydrographs for each K value together with assumed storage weighting factors (x) ranging from 0 to 0.5. Flood peak attenuations were again determined through comparison of the upstream and routed downstream hydrographs and with these, linear relationships between x and these attenuations were developed. Actual weighting factors, corresponding to storage constants, were subsequently determined using these relationships for all attenuations determined from the 1-dimensional model simulations. Using multi-variate regression analysis, the computed values of K and x were correlated to catchment and hydrograph properties and expressions for determining both K and x in terms of these properties were developed. The modified Muskingum routing method based on these regressed expressions for K and x was applied to a case

  6. Protein adsorption from flowing solutions on pure and maleic acid copolymer modified glass particles.

    PubMed

    Klose, Theresia; Welzel, Petra B; Werner, Carsten

    2006-08-01

    The adsorption of human serum albumin (HSA) and lysozyme (LSZ) on pure as well as maleic acid (MA) copolymer coated spherical soda lime glass particles was investigated under flowing conditions. Coating the glass particles with two different maleic acid copolymers alters the properties of the particle surface concerning its charge and hydrophobicity in a well-defined gradation. Frontal chromatography was used to determine the surface concentration of the adsorbed proteins and to establish adsorption isotherms. The introduced methodology was demonstrated to provide a powerful means to study protein adsorption at solid/liquid interfaces. Investigations with virginal and protein-preadsorbed glass particles revealed that even under streaming conditions HSA is irreversibly adsorbed, whereas LSZ partially desorbs. For LSZ and HSA the adsorbed amounts and the isotherms strongly depend on the surface "history", i.e. the presence or absence of preadsorbed protein layers, and the kind of surface modification of the glass. Compared to the soda lime glass surface the adsorption of HSA was strongly increased on surfaces modified with a hydrophobic maleic acid copolymer indicating a strong hydrophobic protein-surface interaction. By coating the surface with a hydrophilic and more negatively charged maleic acid copolymer the adsorption of HSA to that surface was lower and comparable to the adsorption onto plain glass due to the electrostatic repulsion between HSA and the modified surface. In contrast the affinity to any of the investigated particle surfaces was generally higher for LSZ than for HSA which can be mainly attributed to the electrostatic attraction between LZS and the surface. The adsorbed amount of LSZ on the copolymer coated particle surfaces was much higher than on the pure soda lime glass particles indicating superposed hydrophobic interactions in the case of the hydrophobic MA copolymer layer and an increased density of anionic sites as well as interactions of

  7. Endovascular Occlusion of Dural Cavernous Fistulas through a Superior Ophthalmic Vein Approach

    PubMed Central

    Briganti, Francesco; Caranci, Ferdinando; Leone, Giuseppe; Napoli, Manuela; Cicala, Domenico; Briganti, Giuseppe; Tranfa, Fausto; Bonavolontà, Giulio

    2013-01-01

    Summary Dural cavernous fistulas are low-flow vascular malformations with usually benign clinical course and a high rate of spontaneous resolution. Cases with symptom progression must be treated with an endovascular approach by arterial or venous route. We report 30 patients with dural cavernous fistulas treated by coil embolization using surgical exposure and retrograde catheterization of the superior ophthalmic vein (SOV). The procedure resulted in closure of the fistula without other endovascular treatments in all 30 patients and clinical remission or improvement in 20 and eight patients, respectively. Embolization via a SOV approach is a safe and easy endovascular procedure, particularly indicated for dural cavernous fistulas with exclusive or prevalent internal carotid artery feeders and anterior venous drainage. PMID:24199817

  8. Overland flow connectivity on planar patchy hillslopes - modified percolation theory approaches and combinatorial model of urns

    NASA Astrophysics Data System (ADS)

    Nezlobin, David; Pariente, Sarah; Lavee, Hanoch; Sachs, Eyal

    2017-04-01

    Source-sink systems are very common in hydrology; in particular, some land cover types often generate runoff (e.g. embedded rocks, bare soil) , while other obstruct it (e.g. vegetation, cracked soil). Surface runoff coefficients of patchy slopes/plots covered by runoff generating and obstructing covers (e.g., bare soil and vegetation) depend critically on the percentage cover (i.e. sources/sinks abundance) and decrease strongly with observation scale. The classic mathematical percolation theory provides a powerful apparatus for describing the runoff connectivity on patchy hillslopes, but it ignores strong effect of the overland flow directionality. To overcome this and other difficulties, modified percolation theory approaches can be considered, such as straight percolation (for the planar slopes), quasi-straight percolation and models with limited obstruction. These approaches may explain both the observed critical dependence of runoff coefficients on percentage cover and their scale decrease in systems with strong flow directionality (e.g. planar slopes). The contributing area increases sharply when the runoff generating percentage cover approaches the straight percolation threshold. This explains the strong increase of the surface runoff and erosion for relatively low values (normally less than 35%) of the obstructing cover (e.g., vegetation). Combinatorial models of urns with restricted occupancy can be applied for the analytic evaluation of meaningful straight percolation quantities, such as NOGA's (Non-Obstructed Generating Area) expected value and straight percolation probability. It is shown that the nature of the cover-related runoff scale decrease is combinatorial - the probability for the generated runoff to avoid obstruction in unit area decreases with scale for the non-trivial percentage cover values. The magnitude of the scale effect is found to be a skewed non-monotonous function of the percentage cover. It is shown that the cover-related scale

  9. Variable-density saturated flow with modified Darcy's law: The salt lake problem and circulation

    NASA Astrophysics Data System (ADS)

    Wooding, Robin A.

    2007-02-01

    For unsteady variable-density seepage flow, alternative solutions are obtained by taking, respectively, the curl and the divergence of a linear form of Darcy's law, and solving each problem directly, using compatible boundary conditions. This gives a vector potential formulation depending upon the horizontal density gradient, and a pressure formulation depending upon the vertical density gradient, resulting in two complementary solutions. Two velocity fields are obtained by taking the curl of the vector potential solution, and by solving Darcy's law using the gradient of the pressure solution, and corresponding vector potentials are obtained, fairly symmetrically, from these velocities. The novelty is that a linear combination of the two solutions can be made by simple addition or subtraction, with independent scalar coefficients, having broader scope than each of the alternative solutions alone. A two-dimensional model, based on convective plumes in a Hele-Shaw experiment with a macroscopic Rayleigh number of 3975, is treated as a benchmark salt lake problem, having a uniform evaporation layer with 1% noise along one-third part of the upper boundary, with appropriate saline recharge. The coefficients are optimized for maximum circulation. This determines the ratio of the pressure-based solution to the vector potential-based solution, modifying the Rayleigh number downward to an effective value of 3455. Numerical streamlines reveal secondary flow typical of Henry circulation, measured by a peak stream function equal to the circulation flux. From finger geometry, there is better agreement between the numerically calculated plumes and the experimental plumes than has been achieved previously.

  10. Outstanding electrochemical performance of a graphene-modified graphite felt for vanadium redox flow battery application

    NASA Astrophysics Data System (ADS)

    González, Zoraida; Flox, Cristina; Blanco, Clara; Granda, Marcos; Morante, Juan R.; Menéndez, Rosa; Santamaría, Ricardo

    2017-01-01

    The development of more efficient electrode materials is essential to obtain vanadium redox flow batteries (VRFBs) with enhanced energy densities and to make these electrochemical energy storage devices more competitive. A graphene-modified graphite felt synthesized from a raw graphite felt and a graphene oxide water suspension by means of electrophoretic deposition (EPD) is investigated as a suitable electrode material in the positive side of a VRFB cell by means of cyclic voltammetry, impedance spectroscopy and charge/discharge experiments. The remarkably enhanced performance of the resultant hybrid material, in terms of electrochemical activity and kinetic reversibility towards the VO2+/VO2+, and mainly the markedly high energy efficiency of the VRFB cell (c.a. 95.8% at 25 mA cm-2) can be ascribed to the exceptional morphological and chemical characteristics of this tailored material. The 3D-architecture consisting of fibers interconnected by graphene-like sheets positively contributes to the proper development of the vanadium redox reactions and so represents a significant advance in the design of effective electrode materials.

  11. Miniaturized flow system based on enzyme modified PMMA microreactor for amperometric determination of glucose.

    PubMed

    Cerdeira Ferreira, Luís Marcos; da Costa, Eric Tavares; do Lago, Claudimir Lucio; Angnes, Lúcio

    2013-09-15

    This paper describes the development of a microfluidic system having as main component an enzymatic reactor constituted by a microchannel assembled in poly(methyl methacrylate) (PMMA) substrate connected to an amperometric detector. A CO2 laser engraving machine was used to make the channels, which in sequence were thermally sealed. The internal surfaces of the microchannels were chemically modified with polyethyleneimine (PEI), which showed good effectiveness for the immobilization of the glucose oxidase enzyme using glutaraldehyde as crosslinking agent, producing a very effective microreactor for the detection of glucose. The hydrogen peroxide generated by the enzymatic reaction was detected in an electrochemical flow cell localized outside of the reactor using a platinum disk as the working electrode. The proposed system was applied to the differential amperometric determination of glucose content in soft drinks showing good repeatability (DPR=1.72%, n=50), low detection limit (1.40×10(-6)molL(-1)), high sampling frequency (calculated as 345 samples h(-1)), and relatively good stability for long-term use. The results were in close agreement with those obtained by the classical spectrophotometric method utilized to quantify glucose in biological fluids. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. Axisymmetric flow and heat transfer to modified second grade fluid over a radially stretching sheet

    NASA Astrophysics Data System (ADS)

    Khan, Masood; Rahman, Masood ur; Manzur, Mehwish

    In the present work, an analysis is made to the two-dimensional axisymmetric flow and heat transfer of a modified second grade fluid over an isothermal non-linear radially stretching sheet. The momentum and energy equations are modelled and the boundary layer equations are derived. The governing equations for velocity and temperature are turned down into a system of ordinary differential equations by invoking appropriate transformations which are then solved numerically via fourth and fifth order Runge-Kutta Fehlberg method. Moreover, the influence of the pertinent parameters namely the generalized second grade parameter, stretching parameter, the power-law index and the generalized Prandtl number is graphically portrayed. It is inferred that the generalized second grade parameter uplifted the momentum boundary layer while lessened the thermal boundary layer. Furthermore, the impact of stretching parameter is more pronounced for the second grade fluid (m = 0) in contrast with the power-law fluid (k = 0). For some special cases, comparisons are made with previously reported results and an excellent agreement is established.

  13. Endovascular vein harvest: systemic carbon dioxide absorption.

    PubMed

    Maslow, Andrew M; Schwartz, Carl S; Bert, Arthur; Hurlburt, Peter; Gough, Jeffrey; Stearns, Gary; Singh, Arun K

    2006-06-01

    Endovascular vein harvest (EDVH) requires CO(2) insufflation to expand the subcutaneous space, allowing visualization and dissection of the saphenous vein. The purpose of this study was to assess the extent of CO(2) absorption during EDVH. Prospective observational study. Single tertiary care hospital. Sixty patients (30 EDVH and 30 open-vein harvest) undergoing isolated coronary artery bypass graft surgery. Hemodynamic, procedural, and laboratory data were collected prior to (baseline), during, and at it the conclusion (final) of vein harvesting. Data were also collected during cardiopulmonary bypass (CPB). Data were compared by using t tests, analysis of variance, and correlation statistics when needed. There were significant increases in arterial CO(2) (PaCO(2), 35%) and decreases in pH (1.35%) during EDVH. These were associated with increases in heart rate, mean blood pressure, and cardiac output. Within the EDVH group, greater elevations (>10 mmHg) in PaCO2 were more likely during difficult harvest procedures, and these patients exhibited greater increase in heart rate. Elevated CO(2) persisted during CPB, requiring higher systemic gas flows and greater use of phenylephrine to maintain desired hemodynamics. EDVH was associated with systemic absorption of CO(2). Greater absorption was more likely in difficult procedures and was associated with greater hemodynamic changes requiring medical therapy.

  14. Biomechanical Issues in Endovascular Device Design

    PubMed Central

    Moore, James E.

    2009-01-01

    The biomechanical nature of the arterial system and its major disease states provides a series of challenges to treatment strategies. Endovascular device design objectives have mostly centered on short-term challenges, such as deployability and immediate restoration of reliable flow channels. The resulting design features may be at odds with long-term clinical success. In-stent restenosis, endoleaks, and loss of device structural integrity (e.g., strut fractures) are all manifestations of a lack of compatibility between the host vessel biomechanical environment and the implant design. Initial attempts to adapt device designs for increased compatibility, including drug-eluting and bioabsorbable stents, barely begin to explore the ways in which implant design can be modulated in time to minimize risk of failure. Biomechanical modeling has the potential to provide a virtual vascular environment in which new designs can be tested for their implications on long-term tissue reaction. These models will be based on high quality, highly resolved imaging information, as well as mechanobiology experiments from the cellular to the whole tissue level. These models can then be extended to incorporate biodegradation mechanics, facilitating the next generations of devices whose designs (including drug delivery profiles) change with time to enhance healing. The possibility of initiating changes in device design or drug release according to information on vascular healing (through clinical intervention or automated methods) provides the opportunity for truly individualized dynamic device design optimization. PMID:19317580

  15. Emergency endovascular treatment of popliteal aneurysms.

    PubMed

    Saratzis, Athanasios; Melas, Nikolaos; Dixon, Hannah; Saratzis, Nikolaos

    2010-12-01

    Popliteal artery aneurysm (PAA), despite being rare, is the most common peripheral aneurysm. It can present as acute thrombosis and occlusion of the aneurysmal segment, and distal embolization, causing either chronic or acute limb ischemia. It has traditionally been treated with open surgical reconstruction. Endovascular repair of PAAs has recently been applied electively with a favourable early and mid-term outcome; however there is a lack of reports on the endovascular treatment of PAAs presenting with acute complications. This report describes the treatment of a thrombosed PAA in a 58 year old male using an endovascular stent-graft and also provides a systematic review of the literature on the emergency endovascular treatment of PAAs.

  16. Human Thiel-Embalmed Cadaveric Aortic Model with Perfusion for Endovascular Intervention Training and Medical Device Evaluation.

    PubMed

    McLeod, Helen; Cox, Ben F; Robertson, James; Duncan, Robyn; Matthew, Shona; Bhat, Raj; Barclay, Avril; Anwar, J; Wilkinson, Tracey; Melzer, Andreas; Houston, J Graeme

    2017-09-01

    The purpose of this investigation was to evaluate human Thiel-embalmed cadavers with the addition of extracorporeal driven ante-grade pulsatile flow in the aorta as a model for simulation training in interventional techniques and endovascular device testing. Three human cadavers embalmed according to the method of Thiel were selected. Extracorporeal pulsatile ante-grade flow of 2.5 L per min was delivered directly into the aorta of the cadavers via a surgically placed connection. During perfusion, aortic pressure and temperature were recorded and optimized for physiologically similar parameters. Pre- and post-procedure CT imaging was conducted to plan and follow up thoracic and abdominal endovascular aortic repair as it would be in a clinical scenario. Thoracic endovascular aortic repair (TEVAR) and endovascular abdominal repair (EVAR) procedures were conducted in simulation of a clinical case, under fluoroscopic guidance with a multidisciplinary team present. The Thiel cadaveric aortic perfusion model provided pulsatile ante-grade flow, with pressure and temperature, sufficient to conduct a realistic simulation of TEVAR and EVAR procedures. Fluoroscopic imaging provided guidance during the intervention. Pre- and post-procedure CT imaging facilitated planning and follow-up evaluation of the procedure. The human Thiel-embalmed cadavers with the addition of extracorporeal flow within the aorta offer an anatomically appropriate, physiologically similar robust model to simulate aortic endovascular procedures, with potential applications in interventional radiology training and medical device testing as a pre-clinical model.

  17. Acute endovascular reperfusion therapy in ischemic stroke: a systematic review and meta-analysis of randomized controlled trials.

    PubMed

    Osanai, Toshiya; Pasupuleti, Vinay; Deshpande, Abhishek; Thota, Priyaleela; Roman, Yuani; Hernandez, Adrian V; Uchino, Ken

    2015-01-01

    Randomized controlled trials (RCTs) of endovascular therapy for acute ischemic stroke have had inconsistent results. We evaluated the efficacy and safety of endovascular therapy in published RCTs. We performed a systematic review of RCTs of endovascular therapy with thrombolytic or mechanical reperfusion compared with interventions without endovascular therapy. Primary outcome was the frequency of good functional outcome (modified Rankin scale (mRS) of 0-2 at 90 days) and secondary outcomes were mortality at 90 days and symptomatic intracranial hemorrhage (sICH). Random-effects meta-analysis was performed and the Cochrane risk of bias assessment was used to evaluate quality of evidence. Ten studies involving 1,612 subjects were included. Endovascular therapy was not significantly associated with good functional outcome (Relative Risk [RR] =1.17; 95% CI, 0.97 to 1.42; p=0.10 and Absolute Risk Difference [ARD] =7%; 95%CI -0.1% to 14%; p=0.05); heterogeneity was moderate among studies (I2=30%). Mortality was unchanged with endovascular therapy (RR=0.92; 95 % CI, 0.75 to 1.13; p=0.45) and there was no difference in sICH (RR=1.20; 95 % CI, 0.79 to 1.82; p=0.39). The quality of evidence was low for all outcomes and the recommendation is weak for the use of endovascular therapy as per GRADE methodology. Intra-arterial therapy did not show significant increase in good outcomes and no changes in either mortality or sICH in patients with acute ischemic stroke. We need further RCTs with better design and quality to evaluate the true efficacy of endovascular therapy.

  18. Acute Endovascular Reperfusion Therapy in Ischemic Stroke: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

    PubMed Central

    Osanai, Toshiya; Pasupuleti, Vinay; Deshpande, Abhishek; Thota, Priyaleela; Roman, Yuani; Hernandez, Adrian V.; Uchino, Ken

    2015-01-01

    Background Randomized controlled trials (RCTs) of endovascular therapy for acute ischemic stroke have had inconsistent results. We evaluated the efficacy and safety of endovascular therapy in published RCTs. Methods We performed a systematic review of RCTs of endovascular therapy with thrombolytic or mechanical reperfusion compared with interventions without endovascular therapy. Primary outcome was the frequency of good functional outcome (modified Rankin scale (mRS) of 0-2 at 90 days) and secondary outcomes were mortality at 90 days and symptomatic intracranial hemorrhage (sICH). Random-effects meta-analysis was performed and the Cochrane risk of bias assessment was used to evaluate quality of evidence. Results Ten studies involving 1,612 subjects were included. Endovascular therapy was not significantly associated with good functional outcome (Relative Risk [RR] =1.17; 95% CI, 0.97 to 1.42; p=0.10 and Absolute Risk Difference [ARD] =7%; 95%CI -0.1% to 14%; p=0.05); heterogeneity was moderate among studies (I2=30%). Mortality was unchanged with endovascular therapy (RR=0.92; 95 % CI, 0.75 to 1.13; p=0.45) and there was no difference in sICH (RR=1.20; 95 % CI, 0.79 to 1.82; p=0.39). The quality of evidence was low for all outcomes and the recommendation is weak for the use of endovascular therapy as per GRADE methodology. Conclusions Intra-arterial therapy did not show significant increase in good outcomes and no changes in either mortality or sICH in patients with acute ischemic stroke. We need further RCTs with better design and quality to evaluate the true efficacy of endovascular therapy. PMID:25915905

  19. Endovascular arterial interventions with embolic protection devices.

    PubMed

    Cura, M; Cura, A

    2007-12-01

    Endovascular treatment of atherosclerotic lesions can provide a clinical benefit, but arterial interventions are not exempt from complications. Embolization in the peripheral circulation may result in unfavorable outcomes. The purpose of this article is to review the technical applications, the clinical indications, and the risks and benefits of different protection devices, occlusions balloons, and filters commonly used during endovascular interventions in the carotid circulation, renal arteries, and lower extremities.

  20. Correlation of experimental rCBF determinations in goats with flow measurements from a Doppler-modified carotid artery shunt

    SciTech Connect

    Loftus, C.M.; Silvidi, J.A.; Becker, J.A.; Miller, B.V.; Bernstein, D.D.

    1989-01-01

    A carotid artery shunt system has been developed that continuously monitors blood flow rates by embedding a Doppler crystal in the shunt wall. The crystal ranges through a liquid lens that enables it to be placed without violation of the shunt lumen. Because the crystal is at a fixed angle (45 degrees) to the axis of blood flow and the diameter of the lumen remains constant, a linear relationship exists between flow rates and the Doppler velocity signal. This shunt system was previously tested in vitro using a pulsatile pump and was found to be accurate to within 4.7% of the actual flow rate. In the present study, animal (goat) experiments were performed consisting of simultaneous carotid shunt flow and bilateral rCBF measurements by the radiolabeled microsphere technique to determine in vivo the accuracy of this Doppler modified shunt and to ascertain the ability of shunt flow to increase in the face of acute contralateral carotid occlusion. Data from five animals show that in vivo shunt flow can be recorded to within 13% of control rCBF and that shunt flow increases nearly 50% under conditions of distal demand (contralateral carotid occlusion). This device may prove useful in laboratory studies of carotid shunt dynamics and in clinical practice to quickly detect correctable shunt flow abnormalities.

  1. Combined endovascular and open revascularization.

    PubMed

    Slovut, David Paul; Sullivan, Timothy M

    2009-01-01

    The last decade has borne witness to a transformation in the care of patients with vascular disease. There has been a rapid transition towards minimally invasive techniques as interventionalists obtain increasingly advanced catheter-based skills and access to newer and more sophisticated devices. Patients who are not candidates for completely percutaneous revascularization, or those felt to be at prohibitive risk for traditional surgical reconstruction, may benefit from hybrid therapy, a combination of open surgery and endovascular repair that offers patients the opportunity for complete revascularization with decreased morbidity and mortality. This review examines applications of hybrid procedures for treating patients with disabling claudication and limb-threatening ischemia, aortic arch disease, thoracoabdominal aneurysms, extra-cranial carotid disease, and coronary artery disease.

  2. Evaluation of a modified lateral flow immunoassay for detection of high-sensitivity cardiac troponin I and myoglobin.

    PubMed

    Zhu, Jimin; Zou, Nengli; Mao, Hongju; Wang, Ping; Zhu, Danian; Ji, Huoyan; Cong, Hui; Sun, Changjiang; Wang, Huimin; Zhang, Feng; Qian, Juying; Jin, Qinghui; Zhao, Jianlong

    2013-04-15

    We prospectively evaluated the use of lateral flow immunoassay (LFIA) test modified with nanoparticles for combined detection of high-sensitivity cardiac troponin I (hs-cTnI) and myoglobin with the aim of excluding acute myocardial infarction (AMI). Specimens from 173 patients with symptoms suggestive of AMI were collected to measure hs-cTnI and myoglobin using an electrochemiluminescence immunoassay (ECLI) and the LFIA test modified with nanoparticles, and a comparison was performed between the modified method and a commercial LFIA test for detection of the two proteins. The accuracy of the modified LFIA test was also evaluated. Consistent agreement was observed in the quantitative comparison of 173 clinical samples using the modified LFIA and ECLI, and the modified method was more sensitive than the commercial LFIA test. The accuracy of the modified LFIA was <12% for both hs-cTnI and myoglobin. Thus, the new approach has great potential to improve LFIAs test, demonstrating its usefulness for simple screening applications and for sensitivity and quantitative immunoassays for diagnosis ofAMI.

  3. Endovascular Management of Ruptured Distal Anterior Cerebral Artery (Daca) Aneurysms: A Retrospective Review Study.

    PubMed

    Husain, Shakir; Andhitara, Yovita; Jena, Somnath Prasad; Padilla, Jorge; Aritonang, Sahat; Letsoin, Igor

    2017-08-17

    Distal anterior cerebral artery (DACA) aneurysms are rare and their treatment by both surgical clipping or endovascular treatment poses technical difficulties. Earlier studies have reported higher complication rates in DACA aneurysms compared with other aneurysms in the circle of Willis. Therefore, endovascular management of DACA aneurysms still remains as a challenge in their management. To review clinical presentation, angiographic presentation of DACA aneurysms, complication and outcome of their endovascular treatment in our institutional experience. Retrospective review study among 186 patients with intracranial aneurysms treated with endovascular management from September 2009 to December 2013 in Max Superspecialty Hospital, New Delhi, India, 11 patients (5.9%) with 12 DACA aneurysms were studied retrospectively. We reported clinical presentations, cerebral angiographic findings, endovascular treatment, complications and outcomes. The clinical and angiographic outcomes were assessed using modified Rankin scales and Raymond scale, respectively. Of 11 patients, 54.5% were female and 45.5% were male with mean age was 48.4 years (33-65 years). All patients had subarachnoid hemorrhage that indicated ruptured DACA aneurysm. All of DACA aneurysms were small size. Post-coiling angiograms showed complete occlusion in 9 patients. Two patients had intra-procedural aneurysm rupture but without any clinical sequelae and 1 patient had thrombus formation which was thrombolysed at the end of coiling. All patients had good outcome. Our experience with 11 patients showed endovascular management of small DACA aneurysms though associated with higher intra-procedural events, is associated with good outcome. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Endovascular Treatment of Proximal Bilateral Iliac Limb Dislocation and Kinking following Endovascular Abdominal Aortic Aneurysm Repair

    SciTech Connect

    Alerci, Mario; Wyttenbach, Rolf Bogen, Marcel; Segesser, Ludwig K. von; Gallino, Augusto; Inglese, Luigi

    2005-05-15

    We report the case of a 69-year-old man with a late type 1b endoleak due to proximal migration of both iliac limbs 5 years after endovascular repair of an abdominal aortic aneurysm. The endovascular method used to correct bilaterally this condition is described. Final angiographic control shows patency of the stent-graft without signs of endoleak.

  5. Surface Charge, Electroosmotic Flow and DNA Extension in Chemically Modified Thermoplastic Nanoslits and Nanochannels

    PubMed Central

    Uba, Franklin I.; Pullagurla, Swathi R.; Sirasunthorn, Nichanun; Wu, Jiahao; Park, Sunggook; Chantiwas, Rattikan; Cho, Yoonkyoung; Shin, Heungjoo; Soper, Steven A.

    2014-01-01

    Thermoplastics have become attractive alternatives to glass/quartz for microfluidics, but the realization of thermoplastic nanofluidic devices has been slow in spite of the rather simple fabrication techniques that can be used to produce these devices. This slow transition has in part been attributed to insufficient understanding of surface charge effects on the transport properties of single molecules through thermoplastic nanochannels. We report the surface modification of thermoplastic nanochannels and an assessment of the associated surface charge density, zeta potential and electroosmotic flow (EOF). Mixed-scale fluidic networks were fabricated in poly(methylmethacrylate), PMMA. Oxygen plasma was used to generate surface-confined carboxylic acids with devices assembled using low temperature fusion bonding. Amination of the carboxylated surfaces using ethylenediamine (EDA) was accomplished via EDC coupling. XPS and ATR-FTIR revealed the presence of carboxyl and amine groups on the appropriately prepared surfaces. A modified conductance equation for nanochannels was developed to determine their surface conductance and was found to be in good agreement with our experimental results. The measured surface charge density and zeta potential of these devices were lower than glass nanofluidic devices and dependent on the surface modification adopted, as well as the size of the channel. This property, coupled to an apparent increase in fluid viscosity due to nanoconfinement, contributed to the suppression of the EOF in PMMA nanofluidic devices by an order of magnitude compared to the micro-scale devices. Carboxylated PMMA nanochannels were efficient for the transport and elongation of λ-DNA while these same DNA molecules were unable to translocate through aminated nanochannels. PMID:25369728

  6. A modified hood infiltrometer to estimate the soil hydraulic properties from transient water flow measurements

    NASA Astrophysics Data System (ADS)

    Moret-Fernández, David; Latorrre, Borja; Peña, Carolina; González-Cebollada, Cesar

    2015-04-01

    In-situ measurements of soil hydraulic properties on cover soil surfaces are of paramount importance in many agronomic or hydrological researches. The hydraulic properties can be estimated form the cumulative infiltration curve measured with tension infiltrometers. Transient water flow analysis, which means shorter experiments, facilitates its use for in situ field application. This paper presents a portable and modified design of the hood infiltrometer, the hat infiltrometer (HI), which applied on covered soil surfaces, allows estimating the soil hydraulic properties from the measured transient cumulative infiltration curve. The HI consists of a water-supply reservoir jointed to a hat base placed on the soil surface. The base of the hat is closed by a sticks plus plasticine ring system. The HI was tested on two different soils at saturated conditions, and the estimated soprtivity (S) and hydraulic conductivity (K) were compared to the corresponding values obtained with a disc infiltrometer (DI). An additional field experiment was performed to compare the hydraulic properties measured with HI on a bare and a plant-covered soil. Results demonstrated that this design allows hermetically closing the base of the hat without soils surface disturbing. No significant differences between the K and S values estimated with DI and the HI were observed. The S values measured with HI on the covers soil were significantly higher than that measured on the adjacent bare soil. These results indicate that HI can be a viable alternative to estimate the soil hydraulic properties of cover soil surfaces from the measured transient infiltration curve.

  7. Effects of fluid flow on elution of hydrophilic modifier from dialysis membrane surfaces.

    PubMed

    Matsuda, Masato; Sato, Mika; Sakata, Hiroki; Ogawa, Takahisa; Yamamoto, Ken-ichiro; Yakushiji, Taiji; Fukuda, Makoto; Miyasaka, Takehiro; Sakai, Kiyotaka

    2008-01-01

    When uremic blood flows through dialyzers during hemodialysis, dialysis membrane surfaces are exposed to shear stress and internal filtration, which may affect the surface characteristics of the dialysis membranes. In the present study, we evaluated changes in the characteristics of membrane surfaces caused by shear stress and internal filtration using blood substitutes: water purified by reverse osmosis and 6.7 wt% dextran70 solution. We focused on the levels of a hydrophilic modifier, polyvinylpyrrolidone (PVP), on the membrane surface measured by attenuated total reflectance Fourier transform infrared spectroscopy. Experiments involving 4 h dialysis, 0-144 h shear-stress loading, and 4 h dead-end filtration were performed using polyester-polymer alloy (PEPA) and polysulfone (PS) membranes. After the dialysis experiments with accompanying internal filtration, average PVP retention on the PEPA membrane surface was 93.7% in all areas, whereas that on the PS membrane surface was 98.9% in all areas. After the shear-stress loading experiments, PVP retention on the PEPA membrane surface decreased as shear-stress loading time and the magnitude of shear stress increased. However, with the PS membrane, PVP retention scarcely changed. After the dead-end filtration experiments, PVP retention decreased in all areas for both PEPA and PS membranes, but PVP retention on the PEPA membrane surface was lower than that on the PS membrane surface. PVP on the PEPA membrane surface was eluted by both shear stress and internal filtration, while that on the PS membrane surface was eluted only by internal filtration.

  8. Endovascular pseudoaneurysm repair after distal pancreatectomy with celiac axis resection

    PubMed Central

    Sumiyoshi, Tatsuaki; Shima, Yasuo; Noda, Yoshihiro; Hosoki, Shingo; Hata, Yasuhiro; Okabayashi, Takehiro; Kozuki, Akihito; Nakamura, Toshio

    2013-01-01

    Erosive hemorrhage due to pseudoaneurysm is one of the most life-threatening complications after pancreatectomy. Here, we report an extremely rare case of rupture of a pseudoaneurysm of the common hepatic artery (CHA) stump that developed after distal pancreatectomy with en block celiac axis resection (DP-CAR), and was successfully treated through covered stent placement. The patient is a 66-year-old woman who underwent DP-CAR after adjuvant chemoradiotherapy for locally advanced pancreatic body cancer. She developed an intra-abdominal abscess around the remnant pancreas head 31 d after the surgery, and computed tomography (CT) showed an occluded portal vein due to the spreading inflammation around the abscess. Her general condition improved after CT-guided drainage of the abscess. However, 19 d later, she presented with melena, and CT showed a pseudoaneurysm arising from the CHA stump. Because the CHA had been resected during the DP-CAR, this artery could not be used as the access route for endovascular treatment, and instead, we placed a covered stent via the inferior pancreaticoduodenal artery originating from the superior mesenteric artery. After stent placement, cessation of bleeding and anterograde hepatic artery flow were confirmed, and the patient recovered well without any further complications. CT angiography at the 6-mo follow-up indicated the patency of the covered stent with sustained hepatic artery flow. To our knowledge, this is the first reported case of endovascular repair of a pseudoaneurysm that developed after DP-CAR. PMID:24363537

  9. Improved mesenchymal stem cell seeding on RGD-modified poly(L-lactic acid) scaffolds using flow perfusion.

    PubMed

    Alvarez-Barreto, Jose F; Sikavitsas, Vassilios I

    2007-05-10

    Arg-Gly-Asp (RGD) has been widely utilized to increase cell adhesion to three-dimensional scaffolds for tissue engineering. However, cell seeding on these scaffolds has only been carried out statically, which yields low cell seeding efficiencies. We have characterized, for the first time, the seeding of rat mesenchymal stem cells on RGD-modified poly(L-lactic acid) (PLLA) foams using oscillatory flow perfusion. The incorporation of RGD on the PLLA foams improves scaffold cellularity in a dose-dependent manner under oscillatory flow perfusion seeding. When compared to static seeding, oscillatory flow perfusion is the most efficient seeding technique. Cell detachment studies show that cell adhesion is dependent on the applied flow rate, and that cell attachment is strengthened at higher levels of RGD modification.

  10. Endovascular Management of Acute Bleeding Arterioenteric Fistulas

    SciTech Connect

    Leonhardt, Henrik Mellander, Stefan; Snygg, Johan; Loenn, Lars

    2008-05-15

    The objective of this study was to review the outcome of endovascular transcatheter repair of emergent arterioenteric fistulas. Cases of abdominal arterioenteric fistulas (defined as a fistula between a major artery and the small intestine or colon, thus not the esophagus or stomach), diagnosed over the 3-year period between December 2002 and December 2005 at our institution, were retrospectively reviewed. Five patients with severe enteric bleeding underwent angiography and endovascular repair. Four presented primary arterioenteric fistulas, and one presented a secondary aortoenteric fistula. All had massive persistent bleeding with hypotension despite volume substitution and transfusion by the time of endovascular management. Outcome after treatment of these patients was investigated for major procedure-related complications, recurrence, reintervention, morbidity, and mortality. Mean follow-up time was 3 months (range, 1-6 months). All massive bleeding was controlled by occlusive balloon catheters. Four fistulas were successfully sealed with stent-grafts, resulting in a technical success rate of 80%. One patient was circulatory stabilized by endovascular management but needed immediate further open surgery. There were no procedure-related major complications. Mean hospital stay after the initial endovascular intervention was 19 days. Rebleeding occurred in four patients (80%) after a free interval of 2 weeks or longer. During the follow-up period three patients needed reintervention. The in-hospital mortality was 20% and the 30-day mortality was 40%. The midterm outcome was poor, due to comorbidities or rebleeding, with a mortality of 80% within 6 months. In conclusion, endovascular repair is an efficient and safe method to stabilize patients with life-threatening bleeding arterioenteric fistulas in the emergent episode. However, in this group of patients with severe comorbidities, the risk of rebleeding is high and further intervention must be considered

  11. Endovascular Intervention for Peripheral Artery Disease

    PubMed Central

    Thukkani, Arun K.; Kinlay, Scott

    2015-01-01

    Advances in endovascular therapies during the past decade have broadened the options for treating peripheral vascular disease percutaneously. Endovascular treatment offers a lower risk alternative to open surgery in many patients with multiple comorbidities. Noninvasive physiological tests and arterial imaging precede an endovascular intervention and help localize the disease and plan the procedure. The timing and need for revascularization are broadly related to the 3 main clinical presentations of claudication, critical limb ischemia, and acute limb ischemia. Many patients with claudication can be treated by exercise and medical therapy. Endovascular procedures are considered when these fail to improve quality of life and function. In contrast, critical limb ischemia and acute limb ischemia threaten the limb and require more urgent revascularization. In general, endovascular treatments have greater long-term durability for aortoiliac disease than femoral popliteal disease. Infrapopliteal revascularization is generally reserved for critical and acute limb ischemia. Balloon angioplasty and stenting are the mainstays of endovascular therapy. New well-tested innovations include drug-eluting stents and drug-coated balloons. Adjunctive devices for crossing chronic total occlusions or debulking plaque with atherectomy are less rigorously studied and have niche roles. Patients receiving endovascular procedures need a structured surveillance plan for follow-up care. This includes intensive treatment of cardiovascular risk factors to prevent myocardial infarction and stroke, which are the main causes of death. Limb surveillance aims to identify restenosis and new disease beyond the intervened segments, both of which may jeopardize patency and lead to recurrent symptoms, functional impairment, or a threatened limb. PMID:25908731

  12. Endovascular Proximal Forearm Arteriovenous Fistula for Hemodialysis Access: Results of the Prospective, Multicenter Novel Endovascular Access Trial (NEAT).

    PubMed

    Lok, Charmaine E; Rajan, Dheeraj K; Clement, Jason; Kiaii, Mercedeh; Sidhu, Ravi; Thomson, Ken; Buldo, George; Dipchand, Christine; Moist, Louise; Sasal, Joanna

    2017-10-01

    Hemodialysis arteriovenous fistulas (AVFs) are suboptimally used primarily due to problems with maturation, early thrombosis, and patient nonacceptance. An endovascular approach to fistula creation without open surgery offers another hemodialysis vascular access option. Prospective, single-arm, multicenter study (Novel Endovascular Access Trial [NEAT]). Consecutive adult non-dialysis-dependent and dialysis-dependent patients referred for vascular access creation at 9 centers in Canada, Australia, and New Zealand. Using catheter-based endovascular technology and radiofrequency energy, an anastomosis was created between target vessels, resulting in an endovascular AVF (endoAVF). Safety, efficacy, functional usability, and patency end points. Safety as percentage of device-related serious adverse events; efficacy as percentage of endoAVFs physiologically suitable (brachial artery flow ≥ 500mL/min, vein diameter ≥ 4mm) for dialysis within 3 months; functional usability of endoAVFs to provide prescribed dialysis via 2-needle cannulation; primary and cumulative endoAVF patencies per standardized definitions. 80 patients were enrolled (20 roll-in and 60 participants in the full analysis set; the latter are reported). EndoAVFs were created in 98% of participants; 8% had a serious procedure-related adverse event (2% device related). 87% were physiologically suitable for dialysis (eg, mean brachial artery flow, 918mL/min; endoAVF vein diameter, 5.2mm [cephalic vein]). EndoAVF functional usability was 64% in participants who received dialysis. 12-month primary and cumulative patencies were 69% and 84%, respectively. Due to the unique anatomy and vessels used to create endoAVFs, this was a single-arm study without a surgical comparator. An endoAVF can be reliably created using a radiofrequency magnetic catheter-based system, without open surgery and with minimal complications. The endoAVF can be successfully used for hemodialysis and demonstrated high 12-month

  13. Modified Blalock-Taussig shunt versus ductal stenting for palliation of cardiac lesions with inadequate pulmonary blood flow.

    PubMed

    McMullan, David Michael; Permut, Lester Cal; Jones, Thomas Kenny; Johnston, Troy Alan; Rubio, Agustin Eduardo

    2014-01-01

    The modified Blalock-Taussig shunt is the most commonly used palliative procedure for infants with ductal-dependent pulmonary circulation. Recently, catheter-based stenting of the ductus arteriosus has been used by some centers to avoid surgical shunt placement. We evaluated the durability and safety of ductal stenting as an alternative to the modified Blalock-Taussig shunt. A single-institution, retrospective review of patients undergoing modified Blalock-Taussig shunt versus ductal stenting was performed. Survival, procedural complications, and freedom from reintervention were the primary outcome variables. A total of 42 shunted and 13 stented patients with similar age and weight were identified. Survival to second-stage palliation, definitive repair, or 12 months was similar between the 2 groups (88% vs 85%; P = .742). The incidence of surgical or catheter-based reintervention to maintain adequate pulmonary blood flow was 26% in the shunted patients and 25% in the stented patients (P = 1.000). Three shunted patients (7%) required intervention to address contralateral pulmonary artery stenosis and 3 (7%) required surgical reintervention to address nonpulmonary blood flow-related complications. The need for ipsilateral or juxtaductal pulmonary artery intervention at, or subsequent to, second-stage palliation or definitive repair was similar between the 2 groups. Freedom from reintervention to maintain adequate pulmonary blood flow was similar between infants undergoing modified Blalock-Taussig shunt or ductal stenting as an initial palliative procedure. However, a greater percentage of shunted patients experienced procedure-related complications and distal branch pulmonary artery stenosis. Palliative ductal stenting appears to be a safe and effective alternative to modified Blalock-Taussig in selected infants. Copyright © 2014 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

  14. Darkfield orthogonal polarized spectral imaging for studying endovascular laser-tissue interactions in vivo a preliminary study

    NASA Astrophysics Data System (ADS)

    Heger, Michal; Beek, Johan F.; Stenback, Karin; Faber, Dirk J.; van Gemert, Martin J. C.; Ince, Can

    2005-02-01

    Due to the limited number of suitable intravital microscopy techniques, relatively little is known about the opto-thermal (endo)vascular responses to selective photothermolysis, used as a default treatment modality for superficial vascular anomalies such as port wine stains, telangiectasias, and hemangiomas. In this preliminary study we present a novel microscopy technique for studying (endo)vascular laser-tissue interactions in vivo, in which conventional orthogonal polarized spectral (OPS) imaging is combined with darkfield (DF) illumination. DFOPS imaging of rat mesenteric vasculature irradiated at increasing powers revealed the following (tissular) responses: formation of translucent aggregates, retrograde flow, gradual and immediate hemostasis, reinstatement of flow, vessel disappearance, and perivascular collagen damage. DFOPS imaging therefore constitutes a useful tool for examining (endo)vascular events following selective photothermolysis.

  15. Critical Early Thrombolytic & Endovascular Reperfusion Therapy For Acute Ischemic Stroke Victims: A Call for Adjunct Neuroprotection

    PubMed Central

    Lapchak, Paul A.

    2015-01-01

    Today, there is an enormous amount of excitement in the field of stroke victim care due to the recent success of MR. CLEAN, SWIFT PRIME, ESCAPE, EXTEND-IA, and REVASCAT endovascular trials. Successful intravenous (IV) recombinant tissue plasminogen activation (rt-PA) clinical trials [i.e.: National Institutes of Neurodegenerative Disease and Stroke (NINDS) stroke trial; Third European Cooperative Acute Stroke Study (ECASSIII) and Third International Stroke study (IST-3)] also need to be emphasized. In the recent endovascular and thrombolytic trials, there is statistically significant improvement using both the National Institutes of Health Stroke Scale (NIHSS) and the modified Rankin Score (mRS) scale, but neither approach promotes complete recovery in patients enrolled within any particular NIHSS or mRS score tier. Absolute improvement (mRS 0–2 at 90 days) with endovascular therapy is 13.5–31%, whereas thrombolytics alone also significantly improve patient functional independence, but to a lesser degree (NINDS rt-PA trial 13%). This article has 3 main goals: (1) first to emphasize the utility and cost-effectiveness of rt-PA to treat stroke; (2) second to review the recent endovascular trials with respect to efficacy, safety and cost-effectiveness as a stroke treatment; and (3) to further consider and evaluate strategies to develop novel neuroprotective drugs. A thesis will be put forth so that future stroke trials and therapy development can optimally promote recovery so that stroke victims can return to “normal” life. PMID:26314402

  16. Contemporary Endovascular Embolotherapy for Meningioma

    PubMed Central

    Dubel, Gregory J.; Ahn, Sun Ho; Soares, Gregory M.

    2013-01-01

    Preoperative endovascular tumor embolization has been used for 40 years. Meningiomas are the most common benign intracranial tumor in which preoperative embolization has been most extensively described in the literature. Advocates of embolization report that it reduces operative blood-loss, and softens the tumor, thus making surgery safer and easier. Opponents suggest that it adds additional risk and cost for patients without controlled studies showing conclusive benefit. The literature suggests a 3 to 6% neurological complication rate related to embolization. The combined external and internal carotid artery blood supply and complex anastomoses of the meninges can make embolization challenging. Positive outcomes require thorough knowledge of the pertinent vascular anatomy, familiarity with the neurovascular equipment and embolics, and meticulous technique. There remains debate on several aspects of embolization, including tumors most appropriate for embolization, embolic agent of choice, ideal size of embolic, and the choice of vessel(s) to embolize. This detailed review of pertinent vascular anatomy, embolization technique, results, and complications should allow practitioners to maximize treatment outcomes in this setting. PMID:24436548

  17. Analysis of the effect of older drivers’ driving behaviors on traffic flow based on a modified CA model

    NASA Astrophysics Data System (ADS)

    Jian, Mei-Ying; Shi, Jing; Liu, Yang

    2016-09-01

    As the global population ages, there are more and more older drivers on the road. The decline in driving performance of older drivers may influence the properties of traffic flow and safety. The purpose of this paper is to investigate the effect of older drivers’ driving behaviors on traffic flow. A modified cellular automaton (CA) model which takes driving behaviors of older drivers into account is proposed. The simulation results indicate that older drivers’ driving behaviors induce a reduction in traffic flow especially when the density is higher than 15 vehicles per km per lane and an increase in Lane-changing frequency. The analysis of stability shows that a number of disturbances could frequently emerge, be propagated and eventually dissipate in this modified model. The results also reflect that with the increase of older drivers on the road, the probability of the occurrence of rear-end collisions increases greatly and obviously. Furthermore, the value of acceleration influences the traffic flow and safety significantly. These results provide the theoretical basis and reference for the traffic management departments to develop traffic management measure in the aging society.

  18. Computational issues and applications of line-elements to model subsurface flow governed by the modified Helmholtz equation

    NASA Astrophysics Data System (ADS)

    Bakker, Mark; Kuhlman, Kristopher L.

    2011-09-01

    Two new approaches are presented for the accurate computation of the potential due to line elements that satisfy the modified Helmholtz equation with complex parameters. The first approach is based on fundamental solutions in elliptical coordinates and results in products of Mathieu functions. The second approach is based on the integration of modified Bessel functions. Both approaches allow evaluation of the potential at any distance from the element. The computational approaches are applied to model transient flow with the Laplace transform analytic element method. The Laplace domain solution is computed using a combination of point elements and the presented line elements. The time domain solution is obtained through a numerical inversion. Two applications are presented to transient flow fields, which could not be modeled with the Laplace transform analytic element method prior to this work. The first application concerns transient single-aquifer flow to wells near impermeable walls modeled with line-doublets. The second application concerns transient two-aquifer flow to a well near a stream modeled with line-sinks.

  19. Randomized assessment of rapid endovascular treatment of ischemic stroke.

    PubMed

    Goyal, Mayank; Demchuk, Andrew M; Menon, Bijoy K; Eesa, Muneer; Rempel, Jeremy L; Thornton, John; Roy, Daniel; Jovin, Tudor G; Willinsky, Robert A; Sapkota, Biggya L; Dowlatshahi, Dar; Frei, Donald F; Kamal, Noreen R; Montanera, Walter J; Poppe, Alexandre Y; Ryckborst, Karla J; Silver, Frank L; Shuaib, Ashfaq; Tampieri, Donatella; Williams, David; Bang, Oh Young; Baxter, Blaise W; Burns, Paul A; Choe, Hana; Heo, Ji-Hoe; Holmstedt, Christine A; Jankowitz, Brian; Kelly, Michael; Linares, Guillermo; Mandzia, Jennifer L; Shankar, Jai; Sohn, Sung-Il; Swartz, Richard H; Barber, Philip A; Coutts, Shelagh B; Smith, Eric E; Morrish, William F; Weill, Alain; Subramaniam, Suresh; Mitha, Alim P; Wong, John H; Lowerison, Mark W; Sajobi, Tolulope T; Hill, Michael D

    2015-03-12

    Among patients with a proximal vessel occlusion in the anterior circulation, 60 to 80% of patients die within 90 days after stroke onset or do not regain functional independence despite alteplase treatment. We evaluated rapid endovascular treatment in addition to standard care in patients with acute ischemic stroke with a small infarct core, a proximal intracranial arterial occlusion, and moderate-to-good collateral circulation. We randomly assigned participants to receive standard care (control group) or standard care plus endovascular treatment with the use of available thrombectomy devices (intervention group). Patients with a proximal intracranial occlusion in the anterior circulation were included up to 12 hours after symptom onset. Patients with a large infarct core or poor collateral circulation on computed tomography (CT) and CT angiography were excluded. Workflow times were measured against predetermined targets. The primary outcome was the score on the modified Rankin scale (range, 0 [no symptoms] to 6 [death]) at 90 days. A proportional odds model was used to calculate the common odds ratio as a measure of the likelihood that the intervention would lead to lower scores on the modified Rankin scale than would control care (shift analysis). The trial was stopped early because of efficacy. At 22 centers worldwide, 316 participants were enrolled, of whom 238 received intravenous alteplase (120 in the intervention group and 118 in the control group). In the intervention group, the median time from study CT of the head to first reperfusion was 84 minutes. The rate of functional independence (90-day modified Rankin score of 0 to 2) was increased with the intervention (53.0%, vs. 29.3% in the control group; P<0.001). The primary outcome favored the intervention (common odds ratio, 2.6; 95% confidence interval, 1.7 to 3.8; P<0.001), and the intervention was associated with reduced mortality (10.4%, vs. 19.0% in the control group; P=0.04). Symptomatic

  20. Endovascular thrombectomy for stroke: current best practice and future goals.

    PubMed

    Campbell, Bruce C V; Donnan, Geoffrey A; Mitchell, Peter J; Davis, Stephen M

    2016-03-01

    Endovascular thrombectomy for large vessel ischaemic stroke substantially reduces disability, with recent positive randomised trials leading to guideline changes worldwide. This review discusses in detail the evidence provided by recent randomised trials and meta-analyses, the remaining areas of uncertainty and the future directions for research. The data from existing trials have demonstrated the robust benefit of endovascular thrombectomy for internal carotid and proximal middle cerebral artery occlusions. Uncertainty remains for more distal occlusions where the efficacy of alteplase is greater, less tissue is at risk and the safety of endovascular procedures is less established. Basilar artery occlusion was excluded from the trials, but with a dire natural history and proof of principle that rapid reperfusion is effective, it seems reasonable to continue treating these patients pending ongoing trial results. There has been no evidence of heterogeneity in treatment effect in clinically defined subgroups by age, indeed, those aged >80 years have at least as great an overall reduction in disability and reduced mortality. Similarly there was no heterogeneity across the range of baseline stroke severities included in the trials. Evidence that routine use of general anaesthesia reduces the benefit of endovascular thrombectomy is increasing and conscious sedation is generally preferred unless severe agitation or airway compromise is present. The impact of time delays has become clearer with description of onset to imaging and imaging to reperfusion epochs. Delays in the onset to imaging reduce the proportion of patients with salvageable brain tissue. However, in the presence of favourable imaging, rapid treatment appears beneficial regardless of the onset to imaging time elapsed. Imaging to reperfusion delays lead to decay in the clinical benefit achieved, particularly in those with less robust collateral flow. The brain imaging options to assess prognosis have

  1. Endovascular Aneurysm Repair: Current and Future Status

    SciTech Connect

    Hinchliffe, R. J. Ivancev, K.

    2008-05-15

    Endovascular aneurysm repair has rapidly expanded since its introduction in the early 1990s. Early experiences were associated with high rates of complications including conversion to open repair. Perioperative morbidity and mortality results have improved but these concerns have been replaced by questions about long-term durability. Gradually, too, these problems have been addressed. Challenges of today include the ability to roll out the endovascular technique to patients with adverse aneurysm morphology. Fenestrated and branch stent-graft technology is in its infancy. Only now are we beginning to fully understand the advantages, limitations, and complications of such technology. This paper outlines some of the concepts and discusses the controversies and challenges facing clinicians involved in endovascular aneurysm surgery today and in the future.

  2. Endovascular treatment of thoracic aortic fistulas.

    PubMed

    Léobon, Bertrand; Roux, Daniel; Mugniot, Antoine; Rousseau, Hervé; Cérene, Alain; Glock, Yves; Fournial, Gérard

    2002-07-01

    Aortoesophageal and aortobronchial fistulas constitute a problem in therapy because of the high rates of morbidity and mortality associated with operation. From May 1996 to March 2000, we treated by an endovascular procedure one aortoesophageal and three aortobronchial fistulas. There was no postoperative death. We noted one peripheral vascular complication that required a surgical procedure, one postoperative confusion, and one inflammatory syndrome. In one case, because of a persistent leakage after 21 months, we had to implant a second endovascular stent graft. A few weeks later the reopening of this patient's esophageal fistula led to his death by mediastinitis 25 months after the first procedure. The few cases published seem to bear out the interest, observed in our 4 patients, of an endovascular approach to treat complex lesions such as fistulas of the thoracic aorta especially in emergency or palliative cases.

  3. Acute stroke endovascular treatment: tips and tricks.

    PubMed

    Rangel-Castilla, Leonardo; Rajah, Gary B; Shakir, Hakeem J; Davies, Jason M; Snyder, Kenneth V; Siddiqui, Adnan H; Levy, Elad I; Hopkins, L Nelson

    2016-12-01

    Acute ischemic stroke is a leading cause of death and disability in the United States, responsible for 1 of every 20 deaths. The efficacy of intravenous tissue plasminogen activator (tPA) alone for recanalization of large-vessel occlusion (LVO) is low. Several randomized trials have now established endovascular treatment of LVO as a standard of care. Endovascular techniques continue to evolve at a rapid pace. This review seeks to report recent advances in endovascular technology, discuss the correlation between speed of reperfusion and patient outcomes, and present mobile stroke care, shortcoming of the recent technology (such as clot fragmentation), and potential solutions to overcome these drawbacks, as well as anesthetic considerations and cost-effectiveness.

  4. Modified MILLER banding procedure for managing high-flow access and dialysis-associated steal syndrome.

    PubMed

    Shintaku, Sadanori; Kawanishi, Hideki; Moriishi, Misaki; Banshodani, Masataka; Ago, Rika; Tsuchiya, Shinichiro

    2015-01-01

    Both high-flow vascular access (VA) and dialysis-associated steal syndrome are serious complications requiring a flow reduction technique. We adopted the minimally invasive limited ligation endoluminal-assisted revision (MILLER) banding procedure with some modifications to control the high blood flow and steal syndrome during VA procedures and retrospectively assessed the outcome. Seven patients with high-flow access (access flow >1400 ml/min) and five patients with steal syndrome (with pain, coldness, or cyanosis) were treated using the MILLER banding method. Flow volume of the brachial artery was monitored using Doppler ultrasonography during the banding procedure. In patients with steal syndrome, the finger probe of a pulse oximeter was attached to a finger on the ipsilateral side, and the peripheral oxygen saturation (SpO2) was monitored. In the high-flow group, the mean access blood flow (Qa) decreased from 2043 ± 463 ml/min (mean ± SD) to 1248 ± 388 ml/min (p<0.001). In the steal syndrome group, the SpO2 value improved in all steal syndrome patients after banding. Symptoms were almost relieved in two steal syndrome patients. The Qa in the steal group decreased from 997 ± 867 to 548 ± 376 ml/min (p = 0.12). The secondary patency rates of the high-flow and steal groups at 6 months were 83.3% and 50%, respectively. The MILLER banding procedure with intraoperative access flow monitoring is effective to treat high-flow VA and steal syndrome.

  5. Endovascular Repair of Abdominal Aortic Aneurysms

    PubMed Central

    Sternbergh, W. Charles; Yoselevitz, Moises; Money, Samuel R.

    1999-01-01

    Endovascular treatment of abdominal aortic aneurysms (AAAs) is an exciting new minimally invasive treatment option for patients with this disease. Ochsner Clinic has been the only institution in the Gulf South participating in FDA clinical trials of these investigational devices. Early results with endovascular AAA repair demonstrate a trend towards lower mortality and morbidity when compared with traditional open surgery. Length of stay has been reduced by two-thirds with a marked reduction in postoperative pain and at-home convalescence. If the long-term data on efficacy and durability of these devices are good, most AAAs in the future will be treated with this minimally invasive technique. PMID:21845135

  6. Endovascular Neurosurgery: Personal Experience and Future Perspectives.

    PubMed

    Raymond, Jean

    2016-09-01

    From Luessenhop's early clinical experience until the present day, experimental methods have been introduced to make progress in endovascular neurosurgery. A personal historical narrative, spanning the 1980s to 2010s, with a review of past opportunities, current problems, and future perspectives. Although the technology has significantly improved, our clinical culture remains a barrier to methodologically sound and safe innovative care and progress. We must learn how to safely practice endovascular neurosurgery in the presence of uncertainty and verify patient outcomes in real time. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Endovascular and Surgical Treatment of Spinal Dural Arteriovenous Fistulas: Assessment of Post-treatment Clinical Outcome

    PubMed Central

    ZOGOPOULOS, Panagiotis; NAKAMURA, Hajime; OZAKI, Tomohiko; ASAI, Katsunori; IMA, Hiroyuki; KIDANI, Tomoki; KADONO, Yoshinori; MURAKAMI, Tomoaki; FUJINAKA, Toshiyuki; YOSHIMINE, Toshiki

    2016-01-01

    Spinal dural arteriovenous fistulas (DAVFs) are the most commonly encountered vascular malformation of the spinal cord and a treatable cause of progressive para- or tetraplegia. It is an elusive pathology that tends to be under-diagnosed, due to lack of awareness among clinicians, and affects males more commonly than females, typically between the fifth and eighth decades. Early diagnosis and treatment may significantly improve outcome and prevent permanent disability and even mortality. The purpose of our retrospective, single-center study was to determine the long-term clinical and radiographic outcome of patients who have received endovascular or surgical treatment of a spinal DAVF. In particular, during a 6-year period (2009–2014) 14 patients with a spinal DAVF were treated at our department either surgically (n = 4) or endovascularly (n = 10) with detachable coils and/or glue. There was no recurrence in the follow-up period (mean: 36 months, range 3–60 months) after complete occlusion with the endovascular treatment (n = 9; 90%), while only one patient (10%) had residual flow both post-treatment and at 3-month follow-up. All four surgically treated patients (100%) had no signs of residual DAVF on follow-up magnetic resonance angiography (MRA) and/or angiography (mean follow-up period of 9 months). Since improvement or stabilization of symptoms may be seen even in patients with delayed diagnosis and substantial neurological deficits, either endovascular or surgical treatment is always justified. PMID:26466887

  8. Modifying effects of phenotypic plasticity on interactions among natural selection, adaptation and gene flow.

    PubMed

    Crispo, E

    2008-11-01

    Divergent natural selection, adaptive divergence and gene flow may interact in a number of ways. Recent studies have focused on the balance between selection and gene flow in natural populations, and empirical work has shown that gene flow can constrain adaptive divergence, and that divergent selection can constrain gene flow. A caveat is that phenotypic diversification may be under the direct influence of environmental factors (i.e. it may be due to phenotypic plasticity), in addition to partial genetic influence. In this case, phenotypic divergence may occur between populations despite high gene flow that imposes a constraint on genetic divergence. Plasticity may dampen the effects of natural selection by allowing individuals to rapidly adapt phenotypically to new conditions, thus slowing adaptive genetic divergence. On the other hand, plasticity may promote future adaptive divergence by allowing populations to persist in novel environments. Plasticity may promote gene flow between selective regimes by allowing dispersers to adapt to alternate conditions, or high gene flow may result in the selection for increased plasticity. Here I expand frameworks for understanding relationships among selection, adaptation and gene flow to include the effects of phenotypic plasticity in natural populations, and highlight its importance in evolutionary diversification.

  9. Complete regression of a symptomatic, mycotic juxtarenal abdominal aortic aneurysm after treatment with fenestrated endovascular aneurysm repair.

    PubMed

    Durgin, Jonathan M; Arous, Edward J; Kumar, Shivani; Robinson, William P; Simons, Jessica P; Schanzer, Andres

    2016-09-01

    Mycotic abdominal aortic aneurysms are rare and present unique challenges when potential treatment options are considered. Although aortic resection with in situ grafting techniques or extra-anatomic reconstruction are the treatments of choice, endovascular aortic repair has emerged as a suitable alternative in critically ill patients. We report the successful endovascular repair of a symptomatic, mycotic juxtarenal aortic aneurysm using a physician-modified fenestrated endograft. In this patient, with >6 months of follow-up, the aneurysm has completely regressed, illustrating that in select patients with complex mycotic aneurysms, endovascular repair combined with appropriate medical management is a viable treatment strategy. Copyright © 2016 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

  10. Emergency Endovascular Treatment of Sac Rupture for Type IIIa Endoleak in Thoracic Aortic Aneurysm Previously Excluded with Endovascular Repair

    SciTech Connect

    Carrafiello, Gianpaolo Mangini, Monica Bracchi, Elena Recaldini, Chiara; Cocozza, Eugenio; Piffaretti, Gabriele; Pellegrino, Carlo Lagana, Domenico Fugazzola, Carlo

    2010-08-15

    Elective endovascular treatment of thoracic aortic pathology has been applied in a variety of conditions. The complications of thoracic aortic stenting are also well recognized. Endoleak after endovascular repair of thoracic aortic aneurysms is the most frequent complication; among them, type III is the least frequent. Endovascular treatment of type III endoleak is generally performed under elective conditions; less frequently, in emergency. We report a successful emergency endovascular management of post-thoracic endovascular repair for thoracic aortic aneurysm rupture due to type IIIa endoleak.

  11. Advanced catheter technology: is this the answer to overcoming the long learning curve in complex endovascular procedures.

    PubMed

    Riga, C V; Bicknell, C D; Sidhu, R; Cochennec, F; Normahani, P; Chadha, P; Kashef, E; Hamady, M; Cheshire, N J W

    2011-10-01

    Advanced endovascular procedures require a high degree of skill with a long learning curve. We aimed to identify differential increases in endovascular skill acquisition in novices using conventional (CC), manually steerable (MSC) and robotic endovascular catheters (RC). 10 novices cannulated all vessels within a CT-reconstructed pulsatile-flow arch phantom in the Simulated Endovascular Suite. Subjects were randomly assigned to conventional/manually-steerable/robotic techniques as the first procedure undertaken. The operators repeated the task weekly for 5 weeks. Quantitative (cannulation times, wire/catheter-tip movements, vessel wall hits) and qualitative metrics (validated rating scale (IC3ST)) were compared. Subjects exhibited statistically significant differences when comparing initial to final performance for total procedure times and catheter-tip movements with all catheter types. Sequential non-parametric comparisons identified learning curve plateau levels at weeks 2 or 3(RCs, MSCs), and at week 4(CCs) for the majority of metrics. There were significantly fewer catheter-tip movements using advanced catheter technology after training (Week 5: CC 74 IQR(59-89) versus MSC 62(44-81); p = 0.028, and RC 33 (28-44); p = 0.012). RCs virtually eliminated wall hits at the arch (CC 29(28-76) versus RC 8(6-9); p = 0.005) and produced significantly higher overall performance scores (p < 0.02). Advanced endovascular catheters, although more intricate, do not seem to take longer to master and in some areas offer clear advantages with regards to positional control, at a faster rate. RCs seem to be the most intuitive and advanced skill acquisition occurs with minimal training. Robotic endovascular technology may have a significantly shorter path to proficiency allowing an increased number of trainees to attempt more complex endovascular procedures earlier and with a greater degree of safety. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

  12. Photoamperometric flow injection analysis of glucose based on dehydrogenase modified quantum dots-carbon nanotube nanocomposite electrode.

    PubMed

    Ertek, Bensu; Dilgin, Yusuf

    2016-12-01

    In this work, a core-shell quantum dot (QD, ZnS-CdS) was electrodeposited onto multiwalled carbon nanotube modified glassy carbon electrode (ZnS-CdS/MWCNT/GCE) and following glucose dehydrogenase (GDH) was immobilized onto QD modified electrode. The proposed electrode (GDH/ZnS-CdS/MWCNT/GCE) was effectively used for the photoelectrochemical biosensing of glucose in flow injection analysis (FIA) system using a home-made flow cell. Results from cyclic voltammetric and FI amperometric measurements have revealed that GDH/ZnS-CdS/MWCNT/GCE is capable of signaling photoelectrocatalytic activity toward NADH when the surface of enzyme modified electrode was irradiated with a light source (250W Halogen lamp). Thus, photoelectrochemical biosensing of glucose was monitored by recording current-time curve of enzymatically produced NADH at optimized conditions. The biosensor response was found linear over the range 0.010-2.0mM glucose with detection limits of 6.0 and 4.0μM for amperometric and photoamperometric methods, respectively. The relative standard deviations (n=5) for 0.5mM glucose were 5.8% and 3.8% for photoamperometric and amperometric results, respectively. The photoelectrochemical biosensor was successfully applied to the real samples. The results with this biosensor showed good selectivity, repeatability and sensitivity for monitoring glucose in amperometric and photoamperometric FIA studies. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Surveillance after endovascular aortic repair.

    PubMed

    Zaiem, Feras; Almasri, Jehad; Tello, Mouaffaa; Prokop, Larry J; Chaikof, Elliot L; Murad, Mohammad Hassan

    2017-06-26

    The objective of this systematic review and meta-analysis was to evaluate the optimal modality and frequency of surveillance after endovascular aortic repair (EVAR) in adult patients with abdominal aortic aneurysms. We searched for studies of post-EVAR surveillance in MEDLINE In-Process & Other Non-Indexed Citations, MEDLINE, Embase, Cochrane Database of Systematic Reviews, and Scopus through May 10, 2016. The outcomes of interest were endoleaks, mortality, limb ischemia, renal complications, late rupture, and aneurysm-related mortality. Outcomes were pooled using a random-effects model and were reported as incidence rate and 95% confidence interval. Of 1099 candidate references, we included 6 meta-analyses and 52 observational studies. Complication rates were common after EVAR, particularly in the first year. Magnetic resonance imaging had a higher detection rate of endoleaks than computed tomography angiography. Doppler ultrasound had lower diagnostic accuracy, whereas contrast-enhanced ultrasound was likely to be as sensitive as computed tomography angiography. The highest endoleak detection rates were in surveillance approaches that used combined tests. There were no studies that compared different surveillance intervals to determine optimal intervals; however, most studies reported detection rates of patient-important outcomes at 1, 6, 12, 24, 36, 48, and 60 months. Data were insufficient to provide comparative inferences about the best strategy to reduce the risk of patient-important outcomes, such as mortality, limb ischemia, rupture, and renal complications. Several tests with reasonable diagnostic accuracy are available for surveillance after EVAR. The available evidence suggests a high complication rate, particularly in the first year, and provides a rationale for surveillance. Published by Elsevier Inc.

  14. A modified Green-Ampt model for water infiltration and preferential flow

    NASA Astrophysics Data System (ADS)

    Liu, D.

    2015-12-01

    Preferential flow is significant for its contribution to rapid response to hydrologic inputs at the soil surface and unsaturated zone flow, which is critical for flow generation in rainfall-runoff models. In combination with the diffuse and source-responsive flow equations, a new model for water infiltration that incorporates preferential flow is proposed in this paper. Its performance in estimating soil moisture at the catchment scale was tested with observed water content data from the Elder sub-basin of the South Fork Eel River, located in northern California, USA. The case study shows that the new model can improve the accuracy of soil water content simulation even at the catchment scale. The impacts of preferential flow on rainfall-runoff simulation were tested by the MISDc lumped hydrological model for the Elder River basin. 11 significant floods events, which were defined as having flood peak magnitudes greater than 10 times average discharge during the study period, were employed to assess runoff simulation improvement. The accuracy of the runoff simulation incorporating the preferential flow at the catchment scale improved significantly even though more model parameters were expected through the likelihood ratio test.

  15. An exact solution for a constant-strength line-sink satisfying the modified Helmholtz equation for groundwater flow

    NASA Astrophysics Data System (ADS)

    Gusyev, M. A.; Haitjema, H. M.

    2011-04-01

    We obtained an exact solution in terms of the discharge potential for a constant-strength line-sink that satisfies the modified Helmholtz equation for groundwater flow, for example for semi-confined flow and transient flow. The solution is obtained by integrating the potential for a point sink (well) along a straight line element. The potential for the point-sink is the modified Bessel function of the second kind and zero order K0. Since K0 cannot be integrated directly (in closed form) along a line-element, earlier solutions for a line-sink have been obtained by integrating polynomial approximations to K0. These approximations, however, are only valid up to a certain distance from the well and consequently impose a limit on the length of the line-sink. In this paper we integrate an exact series representation for K0 that is valid at any distance from the well, thus allowing integration along line-elements of any length, at least in theory. Numerical difficulties arise when evaluating our expressions at large distances from the line-sink, but these are shown to be of little consequence in practice. We made use of Wirtinger calculus to facilitate integration and also to allow us to arrive at exact expressions for the integrated flux over a poly-line and the total leakage over a domain. These properties are essential when using the solution in the context of the Analytic Element Method (AEM). We demonstrate our solution for the case of semi-confined flow (with leakage) and for the case of transient flow in the context of the Laplace Transform Analytic Element Method (LT-AEM).

  16. Modeling flows over gravel beds by a drag force method and a modified S-A turbulence closure

    NASA Astrophysics Data System (ADS)

    Zeng, C.; Li, C. W.

    2012-09-01

    A double-averaged Navier-Stokes equations (DANS) model has been developed for depth-limited open channel flows over gravels. Three test cases are used to validate the model: an open-channel flow over a densely packed gravel bed with small-scale uniform roughness (D/d50 ˜ 13, d50 = median diameter of roughness elements, D = water depth), open-channel flows over large-scale sparsely distributed roughness elements (D/Δ ˜ 2.3-8.7, Δ = roughness height) and steep slope gravel-bed river flows with D/d50 ˜ 7-25. Various methods of treatment of the gravel-induced resistance effect have been investigated. The results show that the wall function approach (WFA) is successful in simulating flows over small gravels but is not appropriate for large gravels since the vertical profile of the longitudinal velocity does not follow the logarithmic-linear relationship. The drag force method (DFM) performs better but the non-logarithmic velocity distribution generated by sparsely distributed gravels cannot be simulated accurately. Noting that the turbulence length scale within the gravel layer is governed by the gravel size, the DANS model incorporating the DFM and a modified Spalart-Allmaras (S-A) turbulence closure is proposed. The turbulence length scale parameter in the S-A model is modified to address the change in the turbulence structure within the gravel layer. The computed velocity profiles agree well with the corresponding measured profiles in all cases. Particularly, the model reproduces the S-shape velocity profile for sparsely distributed large size roughness elements. The modeling methodology is robust and can be easily integrated into the existing numerical models.

  17. Endovascular embolization of carotid-cavernous fistulas: A pioneering experience in Peru

    PubMed Central

    Plasencia, Andres R.; Santillan, Alejandro

    2012-01-01

    Background: Endovascular embolization represents the method of choice for the treatment of carotid-cavernous fistulas (CCFs). Methods: We report our experience using the endovascular technique in 24 patients harboring 25 CCFs treated between October 1994 and April 2010, with an emphasis on the role of detachable balloons for the treatment of direct CCFs. Results: Of the 16 patients who presented with direct CCFs (Barrow Type A CCFs) (age range, 7–62 years; mean age, 34.3 years), 14 were caused by traumatic injury and 2 by a ruptured internal carotid artery (ICA) aneurysm. Eight patients (age range, 32–71 years; mean age, 46.5 years) presented with nine indirect CCFs (Barrow Types B, C, and D). The clinical follow-up after endovascular treatment ranged from 2 to 108 months (mean, 35.2 months). In two cases (8%), the endovascular approach failed. Symptomatic complications related to the procedure occurred in three patients (12.5%): transient cranial nerve palsy in two patients and a permanent neurological deficit in one patient. Detachable balloons were used in 13 out of 16 (81.3%) direct CCFs and were associated with a cure rate of 92.3%. Overall, the angiographic cure rate was obtained in 22 out of 25 (88%) fistulas. Patients presenting with III nerve palsy improved gradually between 1 day and 6 months after treatment. Good clinical outcomes [modified Rankin scale (mRS) ≤ 2] were observed in 22 out of 24 (91.6%) patients at last follow-up. Conclusions: Endovascular treatment using detachable balloons still constitutes a safe and effective method to treat direct carotid-cavernous fistulas. PMID:22363900

  18. Drip, Ship, and On-Demand Endovascular Therapy for Acute Ischemic Stroke

    PubMed Central

    Park, Man-Seok; Yoon, Woong; Kim, Joon-Tae; Choi, Kang-Ho; Kang, Seung-Ho; Kim, B. Chae; Lee, Seung-Han; Choi, Seong-Min; Kim, Myeong-Kyu; Lee, Ji-Sung; Lee, Eun-Bin; Cho, Ki-Hyun

    2016-01-01

    Background The “drip and ship” approach can facilitate an early initiation of intravenous thrombolysis (IVT) for acute ischemic stroke (AIS) at community hospitals. New endovascular treatment modalities, such as stent retrieval, have further improved the rate of safe and successful recanalization. We assessed the clinical outcomes of on-demand endovascular therapy in patients with AIS who were transported to a comprehensive stroke center under the “drip and ship” paradigm. Methods This retrospective study evaluated prospectively registered patients with acute large vessel occlusions in the anterior circulation who underwent endovascular recanalization after IVT at our regional comprehensive stroke center between January 2011 and April 2014. Clinical outcomes and neuroradiological findings were compared between patients who received IVT at the center (direct visit, DV) and at a community hospital (drip and ship, DS). Results Baseline characteristics such as age, initial National Institutes of Health Stroke Scale (NIHSS) score, and risk factors for stroke were similar, and most patients underwent endovascular therapy with a Solitaire stent (81.9% vs. 89.3% for DV and DS, respectively, P = 0.55). The average initial NIHSS score was 12.15±4.1 (12.06 vs. 12.39 for DV and DS, respectively, P = 0.719). The proportions of long-term favorable outcomes (modified Rankin Scale score ≤2 at 90 days) and successful recanalization (Thrombolysis in Cerebral Ischemia score ≥2b) were not significantly different (P = 0.828 and 0.158, respectively). The mortality rates and occurrences of symptomatic intracerebral hemorrhage were not significantly different (P = 0.999 and 0.267, respectively). Conclusions The “drip and ship” approach with subsequent endovascular therapy is a feasible treatment concept for patients with acute large vessel occlusion in the anterior circulation that could help improve clinical outcomes in patients with AIS. PMID:26938774

  19. Endovascular Radiofrequency Ablation for Varicose Veins

    PubMed Central

    2011-01-01

    or worse as other chronic diseases such as back pain and arthritis. Lower limb VV is a very common disease affecting adults – estimated to be the 7th most common reason for physician referral in the US. There is a very strong familial predisposition to VV. The risk in offspring is 90% if both parents affected, 20% when neither affected and 45% (25% boys, 62% girls) if one parent affected. The prevalence of VV worldwide ranges from 5% to 15% among men and 3% to 29% among women varying by the age, gender and ethnicity of the study population, survey methods and disease definition and measurement. The annual incidence of VV estimated from the Framingham Study was reported to be 2.6% among women and 1.9% among men and did not vary within the age range (40-89 years) studied. Approximately 1% of the adult population has a stasis ulcer of venous origin at any one time with 4% at risk. The majority of leg ulcer patients are elderly with simple superficial vein reflux. Stasis ulcers are often lengthy medical problems and can last for several years and, despite effective compression therapy and multilayer bandaging are associated with high recurrence rates. Recent trials involving surgical treatment of superficial vein reflux have resulted in healing and significantly reduced recurrence rates. Endovascular Radiofrequency Ablation for Varicose Veins RFA is an image-guided minimally invasive treatment alternative to surgical stripping of superficial venous reflux. RFA does not require an operating room or general anaesthesia and has been performed in an outpatient setting by a variety of medical specialties including surgeons and interventional radiologists. Rather than surgically removing the vein, RFA works by destroying or ablating the refluxing vein segment using thermal energy delivered through a radiofrequency catheter. Prior to performing RFA, color-flow Doppler ultrasonography is used to confirm and map all areas of venous reflux to devise a safe and effective

  20. In vivo feasibility of endovascular Doppler optical coherence tomography

    PubMed Central

    Sun, Cuiru; Nolte, Felix; Cheng, Kyle H. Y.; Vuong, Barry; Lee, Kenneth K. C.; Standish, Beau A.; Courtney, Brian; Marotta, Thomas R.; Mariampillai, Adrian; Yang, Victor X. D.

    2012-01-01

    Feasibility of detecting intravascular flow using a catheter based endovascular optical coherence tomography (OCT) system is demonstrated in a porcine carotid model in vivo. The effects of A-line density, radial distance, signal-to-noise ratio, non-uniform rotational distortion (NURD), phase stability of the swept wavelength laser and interferometer system on Doppler shift detection limit were investigated in stationary and flow phantoms. Techniques for NURD induced phase shift artifact removal were developed by tracking the catheter sheath. Detection of high flow velocity (~51 cm/s) present in the porcine carotid artery was obtained by phase unwrapping techniques and compared to numerical simulation, taking into consideration flow profile distortion by the eccentrically positioned imaging catheter. Using diluted blood in saline mixture as clearing agent, simultaneous Doppler OCT imaging of intravascular flow and structural OCT imaging of the carotid artery wall was feasible. To our knowledge, this is the first in vivo demonstration of Doppler imaging and absolute measurement of intravascular flow using a rotating fiber catheter in carotid artery. PMID:23082299

  1. Role of heparin during endovascular therapy for acute ischemic stroke.

    PubMed

    Farook, Naureen; Haussen, Diogo; Sur, Samir; Snelling, Brian; Gersey, Zachary; Yavagal, Dileep; Peterson, Eric

    2016-06-01

    Systemic heparinization has become the mainstay anticoagulant in neurointerventional procedures to prevent thromboembolic complications. Its benefit during endovascular therapy for acute stroke however has not been established. The purpose of this study is to retrospectively evaluate the impact of heparin during endovascular therapy for acute ischemic stroke (AIS). We performed a retrospective review of our interventional stroke database from February 2009 to September 2012 for patients with anterior circulation AIS with ICA-T or MCA M1 occlusions. 76 patients were categorized into 2 groups: intraprocedural vs. no intraprocedural heparin use. Outcomes measured included reperfusion (modified TICI scale), cerebral hemorrhages (ECASS criteria), and 90-day outcomes (modified Rankin scale). Baseline characteristics were similar between heparin and non-heparin treated patients, except for presence of CAD (6% vs. 30%, p=0.01), Coumadin (0% vs. 11%, p=0.04), and NIHSS (15.6±5.0 vs. 18.1±4.6, p=0.03). There was a nonsignificantly higher reperfusion rate achieved in heparin-treated patients compared to non heparin-treated patients (63% vs. 50%, p=0.35). Patients who received heparin had significantly lower rates of hemorrhage (p=0.02). Multivariate logistic regression for good outcome revealed only age (OR 0.86; 95% CI 0.78-0.95; p<0.01), ASPECTS (OR 2.14; 95% CI 1.01-4.50; p=0.04), and successful reperfusion (OR 19.25; 95% CI 2.37-155.95; p<0.01) independently associated with mRS 0-2 at 90 days. The use of intraprocedural heparin in patients with AIS from MCA M1 or ICA-T occlusion was found safe. The impact of heparinization is unclear and warrants further evaluation. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Probabilistic rainfall thresholds for triggering debris flows in a human-modified landscape

    NASA Astrophysics Data System (ADS)

    Giannecchini, Roberto; Galanti, Yuri; D'Amato Avanzi, Giacomo; Barsanti, Michele

    2016-03-01

    In the Carrara Marble Basin (CMB; Apuan Alps, Italy) quarrying has accumulated widespread and thick quarry waste, lying on steep slopes and invading valley bottoms. The Apuan Alps are one of the rainiest areas in Italy and rainstorms often cause landslides and debris flows. The stability conditions of quarry waste are difficult to assess, owing to its textural, geotechnical and hydrogeological variability. Therefore, empirical rainfall thresholds may be effective in forecasting the possible occurrence of debris flows in the CMB. Three types of thresholds were defined for three rain gauges of the CMB and for the whole area: rainfall intensity-rainfall duration (ID), cumulated event rainfall-rainfall duration (ED), and cumulated event rainfall normalized by the mean annual precipitation-rainfall intensity (EMAPI). The rainfall events recorded from 1950 to 2005 was analyzed and compared with the occurrence of debris flows involving the quarry waste. They were classified in events that triggered one or more debris flows and events that did not trigger debris flows. This dataset was fitted using the logistic regression method that allows us to define a set of thresholds, corresponding to different probabilities of failure (from 10% to 90%) and therefore to different warning levels. The performance of the logistic regression in defining probabilistic thresholds was evaluated by means of contingency tables, skill scores and receiver operating characteristic (ROC) analysis. These analyses indicate that the predictive capability of the three types of threshold is acceptable for each rain gauge and for the whole CMB. The best compromise between the number of correct debris flow predictions and the number of wrong predictions is obtained for the 40% probability thresholds. The results obtained can be tested in an experimental debris flows forecasting system based on rainfall thresholds, and could have implications for the debris flow hazard and risk assessment in the CMB.

  3. TRACKING GENE FLOW FROM A GENETICALLY MODIFIED CREEPING BENTGRASS -- METHODS, MEASURES AND LESSONS LEARNED

    EPA Science Inventory

    Creeping bentgrass (CBG) expressing an engineered gene for resistance to glyphosate herbicide is one of the first genetically modified (GM) perennial crops to undergo regulatory review for commercial release by the US Department of Agriculture Animal Plant Health and Inspection S...

  4. TRACKING GENE FLOW FROM A GENETICALLY MODIFIED CREEPING BENTGRASS -- METHODS, MEASURES AND LESSONS LEARNED

    EPA Science Inventory

    Creeping bentgrass (CBG) expressing an engineered gene for resistance to glyphosate herbicide is one of the first genetically modified (GM) perennial crops to undergo regulatory review for commercial release by the US Department of Agriculture Animal Plant Health and Inspection S...

  5. Endovascular Management of Thoracic Aortic Aneurysms

    SciTech Connect

    Fattori, Rossella Russo, Vincenzo; Lovato, Luigi; Buttazzi, Katia; Rinaldi, Giovanni

    2011-12-15

    The overall survival of patients with thoracic aortic aneurysm (TAA) has improved significantly in the past few years. Endovascular treatment, proposed as an alternative to surgery, has been considered a therapeutic innovation because of its low degree of invasiveness, which allows the treatment of even high-surgical risk patients with limited complications and mortality. A major limitation is the lack of adequate evidence regarding long-term benefit and durability because follow-up has been limited to just a few years even in the largest series. The combination of endovascular exclusion with visceral branch revascularization for the treatment of thoraco-abdominal aortic aneurysms involving the visceral aorta has also been attempted. As an alternative, endografts with branches represent a technological evolution that allows treatment of complex anatomy. Even if only small numbers of patients and short follow-up are available, this technical approach, which has with limited mortality (<10%) and paraplegia rates, to expand endovascular treatment to TAA seems feasible. With improved capability to recognize proper anatomy and select clinical candidates, the choice of endovascular stent-graft placement may offer a strategy to optimize management and improve prognosis.

  6. Endovascular Treatment of Giant Splenic Artery Aneurysm

    PubMed Central

    Góes Junior, Adenauer Marinho de Oliveira; Góes, Amanda Silva de Oliveira; de Albuquerque, Paloma Cals; Palácios, Renato Menezes; Abib, Simone de Campos Vieira

    2012-01-01

    Introduction. Visceral artery aneurysms are uncommon. Among them, splenic artery is the most common (46–60%). Most splenic artery aneurysms are asymptomatic and diagnosed incidentally, but its rupture, potentially fatal, occurs in up to 8% of cases. Presentation of Case. A female patient, 64 years old, diagnosed with a giant aneurysm of the splenic artery (approximately 6.5 cm in diameter) was successfully submitted to endovascular treatment by stent graft implantation. Discussion. Symptomatic aneurysms and those larger than 2 cm represent some of the main indications for intervention. The treatment may be by laparotomy, laparoscopy, or endovascular techniques. Among the various endovascular methods discussed in this paper, there is stent graft implantation, a method still few reported in the literature. Conclusion. Although some authors still consider the endovascular approach as an exception to the treatment of SAA, in major specialized centers these techniques have been consolidated as the preferred choice, reserving the surgical approach in cases where this cannot be used. For being a less aggressive approach, it offers an opportunity of treatment to patients considered “high risk” for surgical treatment by laparotomy/laparoscopy. PMID:23316410

  7. Endovascular Treatment of AVF after Hair Transplantation

    SciTech Connect

    Dogan, Sozen; Cinar, Celal; Demirpolat, Gulen; Memis, Ahmet

    2008-07-15

    Arteriovenous fistula (AVF) of the scalp is a very rare complication of hair transplantation. Only 9 cases have been reported in nearly half a century. The diagnosis is clinical but angiography is necessary for defining the angioarchitecture of the lesion. Due to technical developments, endovascular embolization has become the primary treatment for AVF of the scalp.

  8. New devices for a better endovascular approach.

    PubMed

    Bosiers, M; Deloose, K; Callaert, J; Maene, L; Beelen, R; Keirse, K; Verbist, J; Peeters, P

    2013-12-01

    The endovascular approach has known a great evolution in terms of vessel patency and treatment possibilities. Longer and more complex lesions with a difficult anatomy can be addressed by a range of endovascular tools. However, to maintain the patency of the treated lesion is the true challenge. In order to fulfill these long-term expectations, newer devices have been developed. The drug-coated balloon combines local drug uptake with no residual material after treatment. To maintain patency and prevent recoil of the arterial wall, the drug-eluting stent has been created to offer stent support with an antiproliferative drug. The main drawbacks of the drug-coated balloon and the drug-eluting stent are being addressed by the drug-eluting absorbable scaffold. The initial scaffolding support in combination with the drug release during a prolonged period, poses the same advantages while the scaffold is being metabolized over time. This continuing evolution in endovascular tools paves the way to an endovascular treatment for the majority of peripheral artery diseases.

  9. Acute radiation syndrome after endovascular AAA repair.

    PubMed

    Rahimi, Saum A; Coyle, Brian W; Vogel, Todd R; Haser, Paul B; Graham, Alan M

    2011-02-01

    Acute radiation syndrome or radiation sickness is a serious illness that occurs after the body receives a high dose of radiation, typically over a short period of time. This condition may be underrecognized by interventionalists and must be considered whenever performing complex endovascular procedures.

  10. Surgery of intracranial aneurysms previously treated endovascularly.

    PubMed

    Tirakotai, Wuttipong; Sure, Ulrich; Yin, Yuhua; Benes, Ludwig; Schulte, Dirk Michael; Bien, Siegfried; Bertalanffy, Helmut

    2007-11-01

    To perform a retrospective study on the patients who underwent aneurysmal surgery following endovascular treatment. We performed a retrospective study on eight patients who underwent aneurysmal surgery following endovascular treatment (-attempts) with gugliemi detachable coils (GDCs). The indications for surgery, surgical techniques and clinical outcomes were analyzed. The indications for surgical treatment after GDC coiling of aneurysm were classified into three groups. First group: surgery of incompletely coiled aneurysms (n=4). Second group: surgery of mass effect on the neural structures due to coil compaction or rebleeding (n=2). Third group: surgery of vascular complications after endovascular procedure due to parent artery occlusion or thrombus propagation from aneurysm (n=2). Aneurysm obliterations could be performed in all cases confirmed by postoperative angiography. Six patients had an excellent outcome and returned to their profession. Patient's visual acuity was improved. One individual experienced right hemiparesis (grade IV/V) and hemihypesthesia. Microsurgical clipping is rarely necessary for previously coiled aneurysms. Surgical treatment is uncommonly required when an acute complication arises during endovascular treatment, or when there is a dynamic change of a residual aneurysm configuration over time that is considered to be insecure.

  11. Endovascular Treatment of Symptomatic Intracranial Atherosclerotic Disease

    PubMed Central

    Short, Jody L.; Majid, Arshad; Hussain, Syed I.

    2011-01-01

    Symptomatic intracranial atherosclerotic disease (ICAD) is responsible for approximately 10% of all ischemic strokes in the United States. The risk of recurrent stroke may be as high as 35% in patient with critical stenosis >70% in diameter narrowing. Recent advances in medical and endovascular therapy have placed ICAD at the forefront of clinical stroke research to optimize the best medical and endovascular approach to treat this important underlying stroke etiology. Analysis of symptomatic ICAD studies lead to the question that whether angioplasty and/or stenting is a safe, suitable, and efficacious therapeutic strategy in patients with critical stenoses that are deemed refractory to medical management. Most of the currently available data in support of angioplasty and/or stenting in high risk patients with severe symptomatic ICAD is in the form of case series and randomized trial results of endovascular therapy versus medical treatment are awaited. This is a comprehensive review of the state of the art in the endovascular approach with angioplasty and/or stenting of symptomatic ICAD. PMID:21359195

  12. Multiple Intracranial Aneurysms: Endovascular Treatment and Complications

    PubMed Central

    Shen, Xun; Xu, Tao; Ding, Xuan; Wang, Wenlei; Liu, Zhi; Qin, Huaihai

    2014-01-01

    Summary This study evaluated the results of endovascular embolization of multiple intracranial aneurysms. A retrospective hospital chart and radiograph review were made of all patients with multiple intracranial aneurysms seen between March 2010 and January 2011. Ten patients presented with subarachnoid hemorrhage, four with mass effect, two with brain ischemia and twenty were incidental. These 36 patients harbored 84 aneurysms, 63 of which were treated with endovascular techniques, two by surgical clipping, and 19 were left untreated. Of the coil-treated lesions, a complete endovascular occlusion was achieved in 54 aneurysms (85.7%), and eight (12.7%) presented neck remnants with one (1.6%) stented only. Twenty-six patients (72.2%) underwent coil embolization of more than one aneurysm in the first session. Follow-up angiographic studies in 31 patients demonstrated an unchanged or improved result in 93.0% of the aneurysms (53 lesions) and coil compaction in 7.0% (four lesions). The overall clinical outcome was excellent in 33 patients (91.7%), good in one (2.8%) and fair in two (5.5%). Endovascular techniques may be a particularly suitable method for treating multiple intracranial aneurysms. PMID:25207907

  13. Functional outcome after primary endovascular therapy or IV thrombolysis alone for stroke. An observational, comparative effectiveness study.

    PubMed

    Abilleira, Sònia; Ribera, Aida; Dávalos, Antonio; Ribó, Marc; Chamorro, Angel; Cardona, Pere; Molina, Carlos A; Martínez-Yélamos, Antonio; Urra, Xabier; Dorado, Laura; Roquer, Jaume; Martí-Fàbregas, Joan; Aja, Lucía; Tomasello, Alejandro; Castaño, Carlos; Blasco, Jordi; Cánovas, David; Castellanos, Mar; Krupinski, Jerzy; Guimaraens, Leopoldo; Perendreu, Joan; Ustrell, Xavier; Purroy, Francisco; Gómez-Choco, Manuel; Baiges, Joan Josep; Cocho, Dolores; Saura, Júlia; Gallofré, Miquel

    2014-01-01

    Among the acute ischemic stroke patients with large vessel occlusions and contraindications for the use of IV thrombolysis, mainly on oral anticoagulation or presenting too late, primary endovascular therapy is often performed as an alternative to the standard therapy even though evidence supporting the use of endovascular reperfusion therapies is not yet established. Using different statistical approaches, we compared the functional independence rates at 3 months among patients undergoing primary endovascular therapy and patients treated only with IV thrombolysis. We used data from a prospective, government-mandated and externally audited registry of reperfusion therapies for ischemic stroke (January 2011 to November 2012). Patients were selected if treated with either IV thrombolysis alone (n = 1,582) or primary endovascular thrombectomy (n = 250). A series of exclusions were made to homogenize the clinical characteristics among the two groups. We then carried out multivariate logistic regression and propensity score matching analyses on the final study sample (n = 1,179) to compare functional independence at 3 months, as measured by the modified Rankin scale scores 0-2, between the two groups. The unadjusted likelihood of good outcome was poorer among the endovascular group (OR: 0.69; 95% CI: 0.47-1.0). After adjustment, no differences by treatment modality were seen (OR: 1.51; 95% CI: 0.93-2.43 for primary endovascular therapy). Patients undergoing endovascular thrombectomy within 180-270 min (OR: 2.89; 95% CI: 1.17-7.15) and patients with severe strokes (OR: 1.84; 95% CI: 1.02-3.35) did better than their intravenous thrombolysis counterparts. The propensity score-matched analyses with and without adjustment by additional covariates showed that endovascular thrombectomy was as effective as intravenous thrombolysis alone in achieving functional independence (OR for unadjusted propensity score matched: 1.35; 95% CI: 0.9-2.02, OR for adjusted propensity score

  14. Endovascular Treatment with Stent-Retriever Devices for Acute Ischemic Stroke: A Meta-Analysis of Randomized Controlled Trials

    PubMed Central

    Bush, Chad K.; Kurimella, Dayaamayi; Cross, Lee J. S.; Conner, Katherine R.; Martin-Schild, Sheryl; He, Jiang; Li, Changwei; Chen, Jing; Kelly, Tanika

    2016-01-01

    Importance Acute ischemic stroke is a leading cause of death and disability worldwide. Several recent clinical trials have shown that endovascular treatment improves clinical outcomes among patients with acute ischemic stroke. Objective To provide an overall and precise estimate of the efficacy of endovascular treatment predominantly using second-generation mechanical thrombectomy devices (stent-retriever devices) compared to medical management on clinical and functional outcomes among patients with acute ischemic stroke. Data Sources MEDLINE, EMBASE, Cochrane Collaboration Central Register of Controlled Clinical Trials, Web of Science, and NIH ClinicalTrials.gov were searched through November 2015. Study Selection Searches returned 3,045 articles. After removal of duplicates, two authors independently screened titles and abstracts to assess eligibility of 2,495 potentially relevant publications. From these, 38 full-text publications were more closely assessed. Finally, 5 randomized controlled trials of endovascular treatment with predominant use of retrievable stents were selected. Data Extraction and Synthesis Three authors independently extracted information on participant and trial characteristics and clinical events using a standardized protocol. Random effects models were used to pool endovascular treatment effects across outcomes. Main Outcomes and Measures The primary outcome was better functional outcome as measured on the modified Rankin Scale at 90 days of follow-up. Secondary outcomes included all-cause mortality and symptomatic intra-cerebral hemorrhage. Results Five trials representing 1,287 patients were included. Overall, patients randomized to endovascular therapy experienced 2.22 times greater odds of better functional outcome compared to those randomized to medical management (95% CI, 1.66 to 2.98; P < 0.0001). Endovascular therapy was not associated with mortality [OR (95% CI), 0.78 (0.54, 1.12); P = 0.1056] or symptomatic intracerebral

  15. Preclinical testing for aortic endovascular grafts: results of a Food and Drug Administration workshop.

    PubMed

    Abel, Dorothy B; Beebe, Hugh G; Dedashtian, Mark M; Morton, Michael C; Moynahan, Megan; Smith, Loius J; Weinberg, Steven L

    2002-05-01

    Since their introduction into clinical trials in the United States, endovascular aortic grafts have shown various types of problems. Although details of design and construction vary between different endovascular grafts and failure modes have had a variety of causes and clinical effects, the inability of preclinical testing to predict these failures remains common to all endovascular grafts. The need to improve preclinical testing in an attempt to reduce clinical device failures resulted in a Food and Drug Administration-sponsored workshop on endovascular graft preclinical testing held in Rockville, Md, from July 31 to August 1, 2001. FORMAT: The workshop was not designed as a consensus conference. Instead, it provided a forum for bringing stakeholders together to define problems and identify areas of agreement and disagreement. The workshop had 34 invited participants who represented device manufacturers, the medical community, the Food and Drug Administration, and testing facilities, and international attendance was more than 120 people. Discussion centered on: 1, defining the physiologic, anatomic, and morphologic characteristics of abdominal aortic aneurysms before and after endovascular graft treatment; 2, identifying the types of failures that have been observed clinically; and 3, determining which characteristics should be considered during preclinical modeling to better predict clinical performance. Attendees agreed to the need to better define and address anatomic characteristics and changes in the aneurysm after endograft treatment to optimize preclinical testing. Much discussion and little agreement occurred on the importance of flow-related forces on graft performance or the need or ability to define and model physiologic compliance during durability testing. The discussion and conclusions are summarized in this paper and are provided in detail at: http://www.fda.gov/cdrh/meetings/073101workshop.html. The workshop raised awareness of significant

  16. Skin blood flow and local temperature independently modify sweat rate during passive heat stress in humans.

    PubMed

    Wingo, Jonathan E; Low, David A; Keller, David M; Brothers, R Matthew; Shibasaki, Manabu; Crandall, Craig G

    2010-11-01

    Sweat rate (SR) is reduced in locally cooled skin, which may result from decreased temperature and/or parallel reductions in skin blood flow. The purpose of this study was to test the hypotheses that decreased skin blood flow and decreased local temperature each independently attenuate sweating. In protocols I and II, eight subjects rested supine while wearing a water-perfused suit for the control of whole body skin and internal temperatures. While 34°C water perfused the suit, four microdialysis membranes were placed in posterior forearm skin not covered by the suit to manipulate skin blood flow using vasoactive agents. Each site was instrumented for control of local temperature and measurement of local SR (capacitance hygrometry) and skin blood flow (laser-Doppler flowmetry). In protocol I, two sites received norepinephrine to reduce skin blood flow, while two sites received Ringer solution (control). All sites were maintained at 34°C. In protocol II, all sites received 28 mM sodium nitroprusside to equalize skin blood flow between sites before local cooling to 20°C (2 sites) or maintenance at 34°C (2 sites). In both protocols, individuals were then passively heated to increase core temperature ~1°C. Both decreased skin blood flow and decreased local temperature attenuated the slope of the SR to mean body temperature relationship (2.0 ± 1.2 vs. 1.0 ± 0.7 mg·cm(-2)·min(-1)·°C(-1) for the effect of decreased skin blood flow, P = 0.01; 1.2 ± 0.9 vs. 0.07 ± 0.05 mg·cm(-2)·min(-1)·°C(-1) for the effect of decreased local temperature, P = 0.02). Furthermore, local cooling delayed the onset of sweating (mean body temperature of 37.5 ± 0.4 vs. 37.6 ± 0.4°C, P = 0.03). These data demonstrate that local cooling attenuates sweating by independent effects of decreased skin blood flow and decreased local skin temperature.

  17. Aortoiliac elongation after endovascular aortic aneurysm repair.

    PubMed

    Chandra, Venita; Rouer, Martin; Garg, Trit; Fleischmann, Dominik; Mell, Matthew

    2015-07-01

    Aortoiliac elongation after endovascular aortic aneurysm repair (EVAR) is not well studied. We sought to assess the long-term morphologic changes after EVAR and identify potentially modifiable factors associated with such a change. An institutional review board-approved retrospective review was conducted for 88 consecutive patients who underwent EVAR at a single academic center from 2003 to 2007 and who also had at least 2 follow-up computed tomography angiograms (CTAs) available for review up to 5 years after surgery. Standardized centerline aortic lengths and diameters were obtained on Aquarius iNtuition 3D workstation (TeraRecon Inc., San Mateo, CA) on postoperative and all-available follow-up CTAs. Relationships to aortic elongation were determined using Wilcoxon rank-sum test or linear regression (Stata version 12.1, College Station, TX). Changes in length over time were determined by mixed-effects analysis (SAS version 9.3, Cary, NC). The study cohort was composed of mostly men (88%), with a mean age of (76 ± 8) and a mean follow-up of 3.2 years (range, 0.4-7.5 years). Fifty-seven percent of patients (n = 50) had devices with suprarenal fixation and 43% (n = 38) had no suprarenal fixation. Significant lengthening was observed over the study period in the aortoiliac segments, but not in the iliofemoral segments. Aortoiliac elongation over time was not associated with sex (P = 0.3), hypertension (P = 0.7), coronary artery disease (P = 0.3), diabetes (P = 0.3), or tobacco use (P = 0.4), but was associated with the use of statins (P = 0.03) and the presence of chronic obstructive pulmonary disease (P = 0.02). Significant aortic lengthening was associated with increased type I endoleaks (P = 0.03) and reinterventions (P = 0.03). Over the study period, 4 different devices were used; Zenith (Cook Medical Inc., Bloomington, IN), Talent (Medtronic, Minneapolis, MN), Aneuryx (Medtronic), and Excluder (W. L. Gore and Associates Inc., Flagstaff, AZ). After adjusting for

  18. Endovascular thrombectomy with or without systemic thrombolysis?

    PubMed

    Tsivgoulis, Georgios; Katsanos, Aristeidis H; Mavridis, Dimitris; Alexandrov, Anne W; Magoufis, Georgios; Arthur, Adam; Caso, Valeria; Schellinger, Peter D; Alexandrov, Andrei V

    2017-03-01

    Current recommendations advocate that pretreatment with intravenous thrombolysis (IVT) should first be offered to all eligible patients with emergent large vessel occlusion (ELVO) before an endovascular thrombectomy (ET) procedure. However, there are observational data that question the safety and efficacy of IVT pretreatment in patients with ELVO. We performed a meta-analysis of the included subgroups from ET randomized controlled trials (RCTs) to evaluate the comparative efficacy between direct ET without IVT pretreatment and bridging therapy (IVT and ET) in patients with ELVO. We included a total of seven RCTs, including 1764 patients with ELVO (52.8% men). Patients receiving bridging therapy (IVT followed by ET) had lower rates (p = 0.041) of 90-day death/severe dependency (modified Rankin Scale-score of 5-6; 19.0%, 95% CI: 14.1-25.1%) compared with patients receiving only ET (31.0%, 95% CI: 21.2-42.9%). Moreover, patients receiving IVT and ET had a nonsignificant (p = 0.389) trend towards higher 90-day functional independence rates (51.4%, 95% CI: 42.5-60.1%) compared with patients undergoing only ET (41.7%, 95% CI: 24.1-61.7%). Finally, shift-analysis uncovered a nonsignificant trend towards functional improvement at 90 days for bridging therapy over ET (cOR = 1.28, 95% CI: 0.91-1.89; p = 0.155). It should be noted that patients included in the present meta-analysis were not randomized to receive IVT, and thus the two groups (bridging therapy versus ET monotherapy) may differ in terms of baseline characteristics and, in particular, in terms of onset to groin puncture time and thus the risk of confounding bias cannot be ruled out. Despite the limitations and the risk of confounding bias, our findings contradict the recent notion regarding potential equality between ET and bridging therapy in ELVO patients and suggest that IVT and ET are complementary therapies that should be pursued in a parallel and noncompeting fashion.

  19. Flow Visualization at Cryogenic Conditions Using a Modified Pressure Sensitive Paint Approach

    NASA Technical Reports Server (NTRS)

    Watkins, A. Neal; Goad, William K.; Obara, Clifford J.; Sprinkle, Danny R.; Campbell, Richard L.; Carter, Melissa B.; Pendergraft, Odis C., Jr.; Bell, James H.; Ingram, JoAnne L.; Oglesby, Donald M.

    2005-01-01

    A modification to the Pressure Sensitive Paint (PSP) method was used to visualize streamlines on a Blended Wing Body (BWB) model at full-scale flight Reynolds numbers. In order to achieve these conditions, the tests were carried out in the National Transonic Facility operating under cryogenic conditions in a nitrogen environment. Oxygen is required for conventional PSP measurements, and several tests have been successfully completed in nitrogen environments by injecting small amounts (typically < 3000 ppm) of oxygen into the flow. A similar technique was employed here, except that air was purged through pressure tap orifices already existent on the model surface, resulting in changes in the PSP wherever oxygen was present. The results agree quite well with predicted results obtained through computational fluid dynamics analysis (CFD), which show this to be a viable technique for visualizing flows without resorting to more invasive procedures such as oil flow or minitufts.

  20. A modified double distribution lattice Boltzmann model for axisymmetric thermal flow

    NASA Astrophysics Data System (ADS)

    Wang, Zuo; Liu, Yan; Wang, Heng; Zhang, Jiazhong

    2017-04-01

    In this paper, a double distribution lattice Boltzmann model for axisymmetric thermal flow is proposed. In the model, the flow field is solved by a multi-relaxation-time lattice Boltzmann scheme while the temperature field by a newly proposed lattice-kinetic-based Boltzmann scheme. Chapman-Enskog analysis demonstrates that the axisymmetric energy equation in the cylindrical coordinate system can be recovered by the present lattice-kinetic-based Boltzmann scheme for temperature field. Numerical tests, including the thermal Hagen-Poiseuille flow and natural convection in a vertical annulus, have been carried out, and the results predicted by the present model agree well with the existing numerical data. Furthermore, the present model shows better numerical stability than the existing model.

  1. Changes in electrical activation modify the orientation of left ventricular flow momentum: novel observations using echocardiographic particle image velocimetry

    PubMed Central

    Pedrizzetti, Gianni; Martiniello, Alfonso R.; Bianchi, Valter; D'Onofrio, Antonio; Caso, Pio; Tonti, Giovanni

    2016-01-01

    Aims Changes in electrical activation sequence are known to affect the timing of cardiac mechanical events. We aim to demonstrate that these also modify global properties of the intraventricular blood flow pattern. We also explore whether such global changes present a relationship with clinical outcome. Methods and results We investigated 30 heart failure patients followed up after cardiac resynchronization therapy (CRT). All subjects underwent echocardiography before implant and at follow-up after 6+ months. Left ventricular mechanics was investigated at follow-up during active CRT and was repeated after a temporary interruption <5 min later. Strain analysis, performed by speckle tracking, was used to assess the entity of contraction (global longitudinal strain) and its synchronicity (standard deviation of time to peak of radial strain). Intraventricular fluid dynamics, by echographic particle image velocimetry, was used to evaluate the directional distribution of global momentum associated with blood motion. The discontinuation of CRT pacing reflects into a reduction of deformation synchrony and into the deviation of blood flow momentum from the base–apex orientation with the development of transversal flow-mediated haemodynamic forces. The deviation of flow momentum presents a significant correlation with the degree of volumetric reduction after CRT. Conclusion Changes in electrical activation alter the orientation of blood flow momentum. The long-term CRT outcome correlates with the degree of re-alignment of haemodynamic forces. These preliminary results suggest that flow orientation could be used for optimizing the biventricular pacing setting. However, larger prospective studies are needed to confirm this hypothesis. PMID:26060201

  2. A silicon dioxide modified magnetic nanoparticles-labeled lateral flow strips for HBs antigen.

    PubMed

    Zhang, Xueqing; Jiang, Lin; Zhang, Chunlei; Li, Ding; Wang, Can; Gao, Feng; Cui, Daxiang

    2011-12-01

    Herein we reported a new type of silicon dioxide wrapped magnetic nanoparticles-labeled lateral flow strip for detection of HBs antigen in sera. The SiO2 wrapped Fe3O4 nanocomposites were prepared and characterized by HR-TEM, FTIR and magnetometer. As-prepared nanocomposites were used to label anti-HBV surface monoclonal antibody, the lateral flow strips were constructed, and 100 specimens of sera were collected and tested. Results showed that the prepared SiO2 wrapped Fe3O4 nanocomposites were shell/core structure, well dispersed, with the size of 25 nm in diameter, the thickness of the shell was about 3 nm, their magnetic saturation intensity was 44.3 meu g(-1). Clinical sera specimens test results showed that the prepared lateral flow strips were with the detection limitation of 5 pg/mL by naked eye observation, and 0.1 pg/mL by CCD reader or MAR Analyzer, specificity was 100%. In conclusion, one kind of silicon dioxide wrapped magnetic nanoparticles-labeled lateral flow strip for ultrasensitive detection of HBs antigen was successfully developed, its ease of use, sensitiveness and low-cost make it well-suited for population-based on-the-site hepatitis B screening.

  3. Modifying vibrational energy flow in aromatic molecules: effects of ortho substitution.

    PubMed

    Pein, Brandt C; Dlott, Dana D

    2014-02-13

    Ultrafast infrared (IR) Raman spectroscopy was used to measure vibrational energy transfer between nitrobenzene nitro and phenyl groups, in the liquid state at ambient temperature, when ortho substituents (-CH3, -F) were introduced. Quantum chemical calculations were used to assign the vibrations of these molecules to three classes, phenyl, nitro, or global. Combining transient anti-Stokes and Stokes Raman spectra determined the energies of multiple molecular vibrational modes, which were summed to determine the aggregate energies in the phenyl, nitro, or global modes. In a previous study (Pein, B. C.; Sun, Y.; Dlott, D. D., J. Phys. Chem. A 2013, 117, 6066-6072) it was shown that, in nitrobenzene, there was no energy transfer from nitro to phenyl or from nitro to global modes, but there was some transfer from phenyl to nitro and phenyl to global. The ortho substituents activated energy flow from nitro-to-phenyl and nitro-to-global and reduced phenyl-to-nitro flow. The -CH3 substituent entirely shut down the phenyl-to-nitro pathway, presumably by efficiently directing some of the phenyl energy into methyl bending excitations. There is (inefficient) unidirectional vibrational energy flow in nitrobenzene only in the nitro-to-phenyl direction, whereas in o-nitrotoluene, vibrational energy flows only in the nitro-to-phenyl direction.

  4. Local shear stress measurements on an axisymmetric body in a microbubble modified flow field

    NASA Astrophysics Data System (ADS)

    Deutsch, S.; Pal, S.

    1990-12-01

    An array of flush-mounted hot film probes has been used to measure the local shear stress reduction as a result of microbubble injection over an axisymmetric body at the four discrete, free-stream speeds of 4.6, 10.7, 13.2, and 16.8 m/sec. Visualization of the bubble flow pattern supplement these results at intermediate free-stream speeds. At speeds of 10.7 m/sec and above, a circumferential gradient in skin friction, with skin friction reduction larger at the top than at the bottom of the model occurs at some distance downstream of injection. For these speeds, the gradient is stronger at the lower speeds and higher gas injection conditions. Higher speeds tend to drive the axial location of the gradient farther from the injection location. At speeds below 10.7 m/sec, the flow is dominated by a double vortex structure that entrains the bubbles at the bottom and sides of the model and transports them to the top. At sufficiently high gas flow rates a cavity, large enough to be observed visually, is formed just upstream of the vortices, centered near the body midline. The axial position of the cavity is roughly independent of flow speed and gas flow conditions. The transport of bubbles by the vortices, to the top of the body, is the cause of the poor skin friction reduction performance of microbubble injection at low speeds on an axisymmetric shape. Integration of the current local skin friction results gives good agreement with earlier drag balance measurements. The persistence of the drag reduction phenomenon with axial distance as well as the statistics of the shear stress fluctuations are quite similar to what was observed earlier on flat plates.

  5. Wake flow pattern modified by small control cylinders at low Reynolds number

    NASA Astrophysics Data System (ADS)

    Kuo, C.-H.; Chiou, L.-C.; Chen, C.-C.

    2007-08-01

    Passive wake control behind a circular cylinder in uniform flow is studied by numerical simulation for ReD ranging from 80 to 300. Two small control cylinders, with diameter d/D=1/8, are placed at x/D=0.5 and y/D=±0.6. Unlike the 1990 results of Strykowski and Sreenivasan, in the present study, the vortex street behind the main cylinder still exists but the fluctuating lift and the form drag on the main cylinder reduces significantly and monotonously as the Reynolds number increases from 80 to 300. Obstruction of the control cylinders to the incoming flow deflects part of the fluid to pass through the gap between the main and control cylinders, forming two symmetric streams. These streams not only eliminate the flow separation along the rear surface of the main cylinder, they also merge toward the wake centerline to create an advancing momentum in the immediate near-wake region. These two effects significantly reduce the wake width behind the main cylinder and lead to monotonous decrease of the form drag as the Reynolds number increases. As the Reynolds number gets higher, a large amount of the downstream advancing momentum significantly delays the vortex formation farther downstream, leading to a more symmetric flow structure in the near-wake region of the main cylinder. As the Reynolds number increases from 80 to 300, both increasing symmetry of the flow structure in the near-wake and significant delay of the vortex formation are the main reasons for the fluctuating lift to decrease monotonously.

  6. Extending REBOA: Endovascular Variable Aortic Control (EVAC) in a Lethal Model of Hemorrhagic Shock

    PubMed Central

    Williams, Timothy K.; Neff, Lucas P.; Johnson, Michael A.; Russo, Rachel M.; Ferencz, Sarah-Ashley; Davidson, Anders J.; Rasmussen, Todd E.

    2016-01-01

    Background The duration of use and efficacy of Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) is limited by distal ischemia. We developed a hybrid endovascular-extracorporeal circuit variable aortic control (VAC) device to extend REBOA duration in a lethal model of hemorrhagic shock to serve as an experimental surrogate to further development of endovascular variable aortic control (EVAC) technologies. Methods Nine Yorkshire-cross swine were anesthetized, instrumented, splenectomized, and subjected to 30% liver amputation. Following a short period of uncontrolled hemorrhage, REBOA was instituted for 20 minutes. Automated variable occlusion in response to changes in proximal mean arterial pressure was applied for the remaining 70 minutes of the intervention phase using the automated extracorporeal circuit. Damage control surgery and whole blood resuscitation then occurred and the animals were monitored for a total of 6 hours. Results Seven animals survived the initial surgical preparation. After 20 minutes of complete REBOA, regulated flow was initiated through the extracorporeal circuit to simulate VAC and provide perfusion to distal tissue beds during the 90-minute intervention phase. Two animals required circuit occlusion for salvage, while five animals tolerated sustained, escalating restoration of distal blood flow prior to surgical hemorrhage control. Animals tolerating distal flow had preserved renal function, maintained proximal blood pressure, and rapidly weaned from complete REBOA. Conclusion We combined a novel automated, extracorporeal circuit with complete REBOA to achieve endovascular variable aortic control in a swine model of uncontrolled hemorrhage. Our approach regulated proximal aortic pressure, alleviated supra-normal values above the balloon, and provided controlled distal aortic perfusion that reduced ischemia without inducing intolerable bleeding. This experimental model serves as a temporary surrogate to guide future EVAC

  7. Microsurgical Clipping of Intracranial Aneurysms Following Unsuccessful Endovascular Treatment

    PubMed Central

    Yu, J.-L.; Xu, K.; Wang, H.-L.; Wang, B.; Luo, Q.

    2010-01-01

    Summary The purpose of the current study was to examine the reasons for failed endovascular aneurysm coiling and to determine the outcome of immediate microsurgical clipping. From July 2006 to July 2008, 198 patients underwent endovascular coiling at our institute; among them, ten cases were unsuccessful. All of the patients were diagnosed with intracranial aneurysms (ICAs) by cranial computed tomography angiography (CTA), and all underwent endovascular treatment without digital subtraction angiography (DSA). When endovascular coiling failed, the patients were immediately transferred to the operating room for microsurgical clipping under the same anesthetic. The ten patients were divided into three groups based on the cause of endovascular failure and associated clinical features. The clinical follow-up period was between 6-12 months, and all 10 patients had good outcomes following the surgery. Taken together, the results of this study suggest that immediate microsurgical clipping after failed endovascular coiling is efficient and may provide improved outcomes by preventing rebleeding. PMID:20377976

  8. Development of a Flow Modifier for Reducing the Reaction Force of Firefighting Nozzles

    DTIC Science & Technology

    1991-05-07

    Borows Risk & Industrial Safety Consultants, Inc. 268 Howard Street Des Plaines, IL 60018-1906 Contract No. F08635-90- C -0065...ORGftJlZATION MSD PKR FQ1J tffY’able) Contract #F08635-90- C -0065 Be. ADDRESS (City, State, and ZIP Code) 10 . SOURCE OF FUNDING NUMBERS Eglin AFB, Florida...Modifier for Reducing the Reaction Force of Firefighting Nozzles 12. PERSONAL A UTHOR($) C . K. Krishnakumar, s. Atallah, and K. A. Borows 13a . TYPE

  9. Direct power production from a water salinity difference in a membrane-modified supercapacitor flow cell.

    PubMed

    Sales, B B; Saakes, M; Post, J W; Buisman, C J N; Biesheuvel, P M; Hamelers, H V M

    2010-07-15

    The entropy increase of mixing two solutions of different salt concentrations can be harnessed to generate electrical energy. Worldwide, the potential of this resource, the controlled mixing of river and seawater, is enormous, but existing conversion technologies are still complex and expensive. Here we present a small-scale device that directly generates electrical power from the sequential flow of fresh and saline water, without the need for auxiliary processes or converters. The device consists of a sandwich of porous "supercapacitor" electrodes, ion-exchange membranes, and a spacer and can be further miniaturized or scaled-out. Our results demonstrate that alternating the flow of saline and fresh water through a capacitive cell allows direct autogeneration of voltage and current and consequently leads to power generation. Theoretical calculations aid in providing directions for further optimization of the properties of membranes and electrodes.

  10. Enhanced capabilities and modified users manual for axial-flow compressor conceptual design code CSPAN

    NASA Technical Reports Server (NTRS)

    Glassman, Arthur J.; Lavelle, Thomas M.

    1995-01-01

    Modifications made to the axial-flow compressor conceptual design code CSPAN are documented in this report. Endwall blockage and stall margin predictions were added. The loss-coefficient model was upgraded. Default correlations for rotor and stator solidity and aspect-ratio inputs and for stator-exit tangential velocity inputs were included in the code along with defaults for aerodynamic design limits. A complete description of input and output along with sample cases are included.

  11. Hydrodynamic-flow-driven phase evolution in a polymer blend film modified by diblock copolymers

    NASA Astrophysics Data System (ADS)

    Rysz, J.; Ermer, H.; Budkowski, A.; Bernasik, A.; Lekki, J.; Juengst, G.; Brenn, R.; Kowalski, K.; Camra, J.; Lekka, M.; Jedliński, J.

    We have studied surface-directed phase separation in thin films of deuterated polystyrene and poly(bromostyrene) (with 22.7% of monomers brominated) using ^{{3}}He nuclear reaction analysis, dynamic secondary ion mass spectroscopy and atomic force microscopy combined with preferential dissolution. The crossover from competing to neutral surfaces of the critical blend film (cast onto Au) was commenced: polyisoprene-polystyrene diblock copolymers were added and segregated to both surfaces reducing in a tuneable manner the effective interactions. Two main stages of phase evolution are characterised by i) the growth of two surface layers and by ii) the transition from the four-layer to the final bilayer morphology. For increasing copolymer content the kinetics of the first stage is hardly affected but the amplitude of composition oscillations is reduced indicating more fragmented inner layers. As a result, a faster mass flow to the surfaces and an earlier completion of the second stage were observed. The hydrodynamic flow mechanism, driving both stages, is evidenced by nearly linear growth of the surface layer and by mass flow channels extending from the surface layer into the bulk. The final bilayer structure, formed even for the surfaces covered by strongly overlapped copolymers, is indicative of long-range (antisymmetric) surface forces.

  12. Physostomous channel catfish, Ictalurus punctatus, modify swimming mode and buoyancy based on flow conditions.

    PubMed

    Yoshida, Makoto A; Yamamoto, Daisuke; Sato, Katsufumi

    2017-02-15

    The employment of gliding in aquatic animals as a means of conserving energy has been theoretically predicted and discussed for decades. Several studies have shown that some species glide, whereas others do not. Freshwater fish species that widely inhabit both lentic and lotic environments are thought to be able to adapt to fluctuating flow conditions in terms of locomotion. In adapting to the different functional demands of lentic and lotic environments on fish energetics, physostomous (open swim bladder) fish may optimise their locomotion and activity by controlling their net buoyancy; however, few buoyancy studies have been conducted on physostomous fish in the wild. We deployed accelerometers on free-ranging channel catfish, Ictalurus punctatus, in both lentic and lotic environments to quantify their swimming activity, and to determine their buoyancy condition preferences and whether gliding conserves energy. Individual comparisons of swimming efforts between ascent and descent phases revealed that all fish in the lentic environment had negative buoyancy. However, all individuals showed many descents without gliding phases, which was contrary to the behaviour predicted to minimise the cost of transport. The fact that significantly fewer gliding phases were observed in the lotic environment, together with the existence of neutrally buoyant fish, indicated that channel catfish seem to optimise their locomotion through buoyancy control based on flow conditions. The buoyancy optimisation of channel catfish relative to the flow conditions that they inhabit not only reflects differences in swimming behaviour but also provides new insights into the adaptation of physostome fish species to various freshwater environments.

  13. Endovascular therapy including thrombectomy for acute ischemic stroke: A systematic review and meta-analysis with trial sequential analysis.

    PubMed

    Phan, Kevin; Zhao, Dong Fang; Phan, Steven; Huo, Ya Ruth; Mobbs, Ralph J; Rao, Prashanth J; Mortimer, Alex M

    2016-07-01

    One of the primary strategies for the management of acute ischemic stroke is intravenous (IV) thrombolysis with tissue plasminogen activator (t-PA). Over the past decade, endovascular therapies such as the use of stent retrievers to perform mechanical thrombectomy have been found to improve functional outcomes compared to t-PA alone. We aimed to reassess the functional outcomes and complications of IV thrombolysis with and without endovascular treatment for acute ischemic stroke using conventional meta-analysis and trial sequential analysis. Pooled relative risks (RR) and 95% confidence intervals (CI) were calculated for the effect of IV thrombolysis with and without endovascular therapy on functional outcome, mortality and symptomatic intracranial hemorrhage (SICH). Trial sequential analysis was done to strengthen the meta-analysis. We analyzed six randomized controlled trials involving 1943 patients. Patients who received IV thrombolysis with endovascular treatment showed significantly higher rates of excellent functional outcomes (modified Rankin Scale [mRS] 0-1) (RR, 1.75 [95% CI, 1.29-2.39]) compared to those who received IV thrombolysis alone. A similar association was seen for good functional outcomes (mRS 0-2) (RR, 1.56 [95% CI, 1.24-1.96]). Trial sequential analysis demonstrated endovascular treatment increased the RR of a good functional outcome by at least 30% compared to IV thrombolysis alone. There was no significant difference in all-cause mortality for mechanical thrombectomy compared to IV thrombolysis alone or the incidence of SICH at 3month follow-up. Endovascular treatment is more likely to result in a better functional outcome for patients compared to IV thrombolysis alone for acute ischemic stroke. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Endovascular treatment of endoleaks after endovascular abdominal aortic aneurysm repair: personal experience.

    PubMed

    Pozzi Mucelli, F; Doddi, M; Bruni, S; Adovasio, R; Pancrazio, F; Cova, M

    2007-04-01

    This paper describes the different endovascular treatments (cuffs, endografts and embolisation) available for types I, II and III endoleaks occurring after endovascular abdominal aortic aneurysm repair (EVAR). From January 2000 to June 2006, 134 patients (118 men, 16 women; mean age 75.1 years) underwent EVAR. Ten patients (7%) developed significant endoleaks requiring endovascular treatment. Five endoleaks were type I, two were type II and three were type III. Of the five type I endoleaks, four were proximal and one was distal. The proximal endoleaks were treated by cuff deployment, whereas the distal endoleak was treated with a bifurcated graft. Of the two patients with type II endoleak, one was treated by translumbar puncture and coil embolisation, and the other was treated by superselective embolisation of the lumbar feeding vessel with nonresorbable particles. Of the three patients with type III endoleak, two were treated by deploying an aortouniiliac endograft inside the bifurcated graft and the other by implanting a cuff to restore continuity between the graft body and the contralateral limb. Endovascular treatment was successful in 6/10 cases, whereas three cases required surgical conversion. One patient did not undergo surgery owing to poor general condition. The reported incidence of endoleaks after EVAR is 10%-20%. Significant endoleaks should be treated promptly. Endovascular treatment can be done with different techniques, but success in not constant due to adverse anatomical conditions and technical difficulties.

  15. Pressure- and flow-controlled media perfusion differently modify vascular mechanics in lung decellularization.

    PubMed

    da Palma, Renata K; Campillo, Noelia; Uriarte, Juan J; Oliveira, Luis V F; Navajas, Daniel; Farré, Ramon

    2015-09-01

    Organ biofabrication is a potential future alternative for obtaining viable organs for transplantation. Achieving intact scaffolds to be recellularized is a key step in lung bioengineering. Perfusion of decellularizing media through the pulmonary artery has shown to be effective. How vascular perfusion pressure and flow vary throughout lung decellularization, which is not well known, is important for optimizing the process (minimizing time) while ensuring scaffold integrity (no barotrauma). This work was aimed at characterizing the pressure/flow relationship at the pulmonary vasculature and at how effective vascular resistance depends on pressure- and flow-controlled variables when applying different methods of media perfusion for lung decellularization. Lungs from 43 healthy mice (C57BL/6; 7-8 weeks old) were investigated. After excision and tracheal cannulation, lungs were inflated at 10 cmH2O airway pressure and subjected to conventional decellularization with a solution of 1% sodium dodecyl sulfate (SDS). Pressure (PPA) and flow (V'PA) at the pulmonary artery were continuously measured. Decellularization media was perfused through the pulmonary artery: (a) at constant PPA=20 cmH2O or (b) at constant V'PA=0.5 and 0.2 ml/min. Effective vascular resistance was computed as Rv=PPA/V'PA. Rv (in cmH2O/(ml/min)); mean±SE) considerably varied throughout lung decellularization, particularly for pressure-controlled perfusion (from 29.1±3.0 in baseline to a maximum of 664.1±164.3 (p<0.05), as compared with flow-controlled perfusion (from 49.9±3.3 and 79.5±5.1 in baseline to a maximum of 114.4±13.9 and 211.7±70.5 (p<0.05, both), for V'PA of 0.5 and 0.2 ml/min respectively. Most of the media infused to the pulmonary artery throughout decellularization circulated to the airways compartment across the alveolar-capillary membrane. This study shows that monitoring perfusion mechanics throughout decellularization provides information relevant for optimizing the process

  16. Computational method to predict thermodynamic, transport, and flow properties for the modified Langley 8-foot high-temperature tunnel

    NASA Technical Reports Server (NTRS)

    Venkateswaran, S.; Hunt, L. Roane; Prabhu, Ramadas K.

    1992-01-01

    The Langley 8 foot high temperature tunnel (8 ft HTT) is used to test components of hypersonic vehicles for aerothermal loads definition and structural component verification. The test medium of the 8 ft HTT is obtained by burning a mixture of methane and air under high pressure; the combustion products are expanded through an axisymmetric conical contoured nozzle to simulate atmospheric flight at Mach 7. This facility was modified to raise the oxygen content of the test medium to match that of air and to include Mach 4 and Mach 5 capabilities. These modifications will facilitate the testing of hypersonic air breathing propulsion systems for a wide range of flight conditions. A computational method to predict the thermodynamic, transport, and flow properties of the equilibrium chemically reacting oxygen enriched methane-air combustion products was implemented in a computer code. This code calculates the fuel, air, and oxygen mass flow rates and test section flow properties for Mach 7, 5, and 4 nozzle configurations for given combustor and mixer conditions. Salient features of the 8 ft HTT are described, and some of the predicted tunnel operational characteristics are presented in the carpet plots to assist users in preparing test plans.

  17. Computational method to predict thermodynamic, transport, and flow properties for the modified Langley 8-foot high-temperature tunnel

    NASA Astrophysics Data System (ADS)

    Venkateswaran, S.; Hunt, L. Roane; Prabhu, Ramadas K.

    1992-07-01

    The Langley 8 foot high temperature tunnel (8 ft HTT) is used to test components of hypersonic vehicles for aerothermal loads definition and structural component verification. The test medium of the 8 ft HTT is obtained by burning a mixture of methane and air under high pressure; the combustion products are expanded through an axisymmetric conical contoured nozzle to simulate atmospheric flight at Mach 7. This facility was modified to raise the oxygen content of the test medium to match that of air and to include Mach 4 and Mach 5 capabilities. These modifications will facilitate the testing of hypersonic air breathing propulsion systems for a wide range of flight conditions. A computational method to predict the thermodynamic, transport, and flow properties of the equilibrium chemically reacting oxygen enriched methane-air combustion products was implemented in a computer code. This code calculates the fuel, air, and oxygen mass flow rates and test section flow properties for Mach 7, 5, and 4 nozzle configurations for given combustor and mixer conditions. Salient features of the 8 ft HTT are described, and some of the predicted tunnel operational characteristics are presented in the carpet plots to assist users in preparing test plans.

  18. Accuracy of Computational Cerebral Aneurysm Hemodynamics Using Patient-Specific Endovascular Measurements

    NASA Astrophysics Data System (ADS)

    McGah, Patrick; Levitt, Michael; Barbour, Michael; Mourad, Pierre; Kim, Louis; Aliseda, Alberto

    2013-11-01

    We study the hemodynamic conditions in patients with cerebral aneurysms through endovascular measurements and computational fluid dynamics. Ten unruptured cerebral aneurysms were clinically assessed by three dimensional rotational angiography and an endovascular guidewire with dual Doppler ultrasound transducer and piezoresistive pressure sensor at multiple peri-aneurysmal locations. These measurements are used to define boundary conditions for flow simulations at and near the aneurysms. The additional in vivo measurements, which were not prescribed in the simulation, are used to assess the accuracy of the simulated flow velocity and pressure. We also performed simulations with stereotypical literature-derived boundary conditions. Simulated velocities using patient-specific boundary conditions showed good agreement with the guidewire measurements, with no systematic bias and a random scatter of about 25%. Simulated velocities using the literature-derived values showed a systematic over-prediction in velocity by 30% with a random scatter of about 40%. Computational hemodynamics using endovascularly-derived patient-specific boundary conditions have the potential to improve treatment predictions as they provide more accurate and precise results of the aneurysmal hemodynamics. Supported by an R03 grant from NIH/NINDS

  19. A modified Cre-lox genetic switch to dynamically control metabolic flow in Saccharomyces cerevisiae.

    PubMed

    Yamanishi, Mamoru; Matsuyama, Takashi

    2012-05-18

    The control of metabolic flow is a prerequisite for efficient chemical production in transgenic microorganisms. Exogenous genes required for the biosynthesis of target chemicals are expressed under strong promoters, while the endogenous genes of the original metabolic pathway are repressed by disruption or mutation. These genetic manipulations occasionally cause harmful effects to the host. In the lactate-producing yeast Saccharomyces cerevisiae, where endogenous pyruvate decarboxylase (PDC) is disrupted and exogenous lactate dehydrogenase (LDH) is introduced, PDC deletion is extremely detrimental to cell growth but is required for efficient production of lactate. A suitable means to dynamically control the metabolic flow from ethanol fermentation during the growth phase to lactate fermentation during the production phase is needed. Here, we demonstrated that this flow can be controlled by the exclusive expression of PDC and LDH with a Cre-lox genetic switch. This switch was evaluated with a gene cassette that encoded two different fluorescence proteins and enabled changes in genotype and phenotype within 2 and 10 h, respectively. Transgenic yeast harboring this switch and the PDC-LDH cassette showed a specific growth rate (0.45 h (-1)) that was almost the same as that of wild-type (0.47 h (-1)). Upon induction of the genetic switch, the transgenic yeast produced lactate from up to 85.4% of the glucose substrate, while 91.7% of glucose went to ethanol before induction. We thus propose a "metabolic shift" concept that can serve as an alternative means to obtain gene products that are currently difficult to obtain by using conventional methodologies.

  20. Interaction of droplet and sidewalls with modified surfaces in a PEMFC gas flow channel

    NASA Astrophysics Data System (ADS)

    Shah, Mihir M.

    A Proton Exchange Membrane Fuel Cell (PEMFC) is a clean and highly efficient way of power generation used primarily for transportation applications. Hydrogen and air are supplied to the fuel cell through gas channels, which also remove liquid water generated in the fuel cell. The clogged channels prevent reactant transport to the electrochemically active sites which comprise one of the channel walls and thus, degrading the performance of the cell. Proper management of the product water is a current topic of research interest in commercialization of fuel cell vehicles. Liquid water, produced as by-product of the fuel cell reaction, can clog the gas channels easily since surface tension of water is significant at this length scale. In a PEMFC channel cross-section, water is assumed to be produced in the channel at the center along the flow axis. This assumption is primarily valid and extensively used for experimental purposes. However in a real PEMFC, the water entry is not constrained at the channel center. Hence, more investigations are made using water entry at channel corner (land region) which resulted in contradicting prior results for the water feature behavior for all relevant PEMFC operating conditions, leading to adverse two-phase flow behavior- including slug blockage and fluctuations at channel end. Very limited research is available to study the effect of gas channel surface modifications on the two-phase flow behavior and local PEMFC performance. In this study, the droplet--sidewall dynamic interactions and two--phase local pressure drop across the water droplet present in a PEMFC channel with trapezoidal geometries with surface modifications are studied. These surface modifications include micro-grooves that possess a hybrid wetting regime that will initiate and guide the water feature at channel ends to eject with general ease. Slugs are reduced to films after ejection and thus channel blockage is avoided overcoming the problems caused by water influx

  1. Complete endovascular debranching of the aortic arch: A report of two cases

    PubMed Central

    Anderson, Joseph; Nykamp, Madeline; Remund, Tyler

    2015-01-01

    Patients suffering from aortic arch aneurysms continue to encounter few treatment options. Because of co-morbidities, most are deemed to not be open surgical candidates. The two cases presented here demonstrate a novel endovascular approach in the care of an arch aneurysm complicated by dissection. Even though final graft configurations differed slightly between the two cases, all three great vessels were successfully de-branched through the combination of standard endovascular aneurysm repair techniques and modifications to off-the-shelf devices. Aortic flow was compartmentalized in the ascending aorta at or near the level of the sinotubular junction. This was done with a physician-assembled endografts. One of these lumens was dedicated to the descending aorta, while the other was further divided into three channels used to stent the great vessels. Completion angiography demonstrated patency in the arch, great vessels, and descending aorta. No endoleaks have been reported. Although data is limited, this approach appears promising. PMID:25015113

  2. Multimodal endovascular treatment of a vertebrovertebral fistula presenting with subarachnoid hemorrhage and hydrocephalus.

    PubMed

    Walcott, Brian P; Berkhemer, Olvert A; Leslie-Mazwi, Thabele M; Chandra, Ronil V; Ogilvy, Christopher S; Yoo, Albert J

    2013-09-01

    Vertebrovertebral fistulae are rare vascular malformations that uncommonly can rupture to present clinically as intracranial subarachnoid hemorrhage. We report a 69-year-old man presenting following spontaneous apoplectic collapse. Initial workup revealed diffuse, intracranial subarachnoid hemorrhage, intraventricular hemorrhage and hydrocephalus. However, the etiology was not apparent on CT angiography of the head. Catheter-based angiography was performed, demonstrating a single-hole, high-flow vertebrovertebral fistula, arising from the V2 segment and decompressing into both cervical and skull base venous structures. Definitive treatment consisted of endovascular fistula obliteration with a combination of coil and liquid embolic material. The patient made a full neurological recovery. High cervical and skull base fistulae are rare causes of intracranial hemorrhage; endovascular treatment is effective at disconnection of the arteriovenous shunt.

  3. Triamine-Modified Polyimides Having Improved Processability and Low Melt Flow Viscosity

    NASA Technical Reports Server (NTRS)

    Meador, Michael A. (Inventor); Nguyen, Baochan N. (Inventor); Eby, Ronald K. (Inventor)

    2001-01-01

    Addition-cured polyimides that contain the reaction product of an aromatic triamine or trianhydride analogue thereof, a reactive end group such as 5-norbornene-2, 3-dicarboxylic acid, ester derivatives of 5-norbornene-2, 3-dicarboxylic acid, anhydride derivatives of 5-norbornene-2, 3-dicarboxylic acid, or 4-phenylethynylphthalic anhydride, an aromatic diamine, and a dialkyl ester of an aromatic tetracarboxylic acid. The resultant starlike polyimides; exhibit lower melt flow viscosity than its linear counterparts, providing for improved processability of the polyimide. Also disclosed are methods for the synthesis of these polyimides as well as composite structures formed using these polyimides.

  4. Modified reaction mechanism of aerated n-dodecane liquid flowing over heated metal tubes

    NASA Technical Reports Server (NTRS)

    Reddy, K. T.; Cernansky, N. P.; Cohen, R. S.

    1988-01-01

    The degradation mechanism of the n-dodecane was studied using a modified jet fuel thermal oxidation tester containing a sample withdrawal system as a reaction vessel. The reaction products were identified using gas chromatography and mass spectorometry. The soluble products were found to consist mainly of C5-C10 n-alkanes and 1-alkenes, C7-C10 aldehydes, tetrahydrofuran derivatives, dodecanol and dodecanone isomers, dodecyl hydroperoxide (ROOH) decomposition products, and C24 alkane isomers. The data from the experiments agreed with those of Hazlett et al. (1977). It was found that alkyl peroxide radical reactions dominate in the autooxidation temperature regime (at T not above 300 C); the dominant path is for the alkyl peroxyl radical to react bimolecularly with fuel to yield primarily alkyl hydroperoxides. The alkyl peroxide radical also undergoes self-termination and unimolecular isomerization and decomposition reactions, to yield smaller amounts of C12 alcohol plus ketone products and tetrahydrofuran derivatives, respectively.

  5. Endovascular management of vertebrobasilar artery dissecting aneurysms.

    PubMed

    Wang, Jian; Sun, Zhigang; Bao, Jinsuo; Li, Zhaohui; Bai, Dongsong; Cao, Shuwei

    2013-01-01

    The prognosis of VBA aneurysms seems poor and surgical management of VBA dissecting aneurysms is challenging. We evaluated our endovascular experience in management of ruptured and unruptured VBA dissecting aneurysms. Eleven consecutive patients with eleven VBA aneurysms (3 ruptured and 8 unruptured) between 2008 and 2010 were retrospectively reviewed. Immediate postprocedural angiograms showed complete occlusion in 5 and subtotal occlusion in 2 aneurysms treated with stentassisted coiling, whereas no occlusion in 4 aneurysms treated with stenting alone. A clinical improvement or stable outcome was achieved in all patients. There was no complication in our patients and no patient died after treatment. Angiographic follow-up (mean 9.7 months, 1 to 23 months) showed complete cure in 8 aneurysms, subtotal occlusion in 2 and no occlusion in 1. VBA dissecting aneurysms can be managed by endovascular stent placement with or without coiling. In cases that cannot be treated with neurostents, proximal occlusion could be an option.

  6. Periprocedural complications in endovascular stroke treatment

    PubMed Central

    Yilmaz, Guliz

    2016-01-01

    Endovascular stroke treatment is a neurointerventional emergency where the main goal is the early recanalization of the occlusion within the critical time window, as safely as possible. Although the time window and rate of complications for endovascular stroke treatment differ with anterior and posterior circulation strokes, awareness of potential periprocedural complications is important, as they affect patient morbidity and mortality. Periprocedural complications are classified as haemorrhagic complications, procedure-/device-related, puncture site complications, and late-onset events including vascular stenosis. We present the digital subtraction angiography and CT imaging findings related to these complications in a study of 56 stroke patients, as they relate to previous findings in the literature. PMID:26529228

  7. Analytical applications of a carbon nanotubes composite modified with copper microparticles as detector in flow systems.

    PubMed

    Arribas, Alberto Sánchez; Bermejo, Esperanza; Chicharro, Manuel; Zapardiel, Antonio; Luque, Guillermina L; Ferreyra, Nancy F; Rivas, Gustavo A

    2006-09-08

    In this work we report on the successful use of a composite prepared by dispersion of multi-wall carbon nanotubes (1-5 microm length, 20-50 nm diameter) and copper microparticles within mineral oil as detector for amino acids quantification in flow injection analysis and capillary electrophoresis. The resulting electrode displays a highly sensitive amperometric detection of amino acids, based on the copper dissolution facilitated by the strong activity of amino acids as ligands of Cu(II). The sensor makes possible the detection of amino acids, electroactive or not, at very low potentials (0.000 V) and physiological pH. A correlation between the sensitivity for the amino acids and the amount of copper within the composite is observed, demonstrating the importance of the metal in the sensor response. The best analytical performance is obtained for the electrode containing 12.0% (w/w) copper. The excellent results obtained with the carbon nanotube paste electrodes containing copper (CNTPE-Cu) as detector in flow systems makes them an interesting alternative for further analytical applications involving different bioanalytes.

  8. Endovascular Exclusion of Renal Artery Aneurysm

    SciTech Connect

    Andersen, Poul Erik Rohr, Nils

    2005-06-15

    A patient who was operated for an abdominal aortic aneurysm 7 years earlier presented with recently discovered iliac and renal artery aneurysms. The renal artery had an angulation of 90{sup o}, but the aneurysm was successfully excluded using a covered vascular stent graft placed over an extrastiff guidewire. Even in cases of complex anatomy of a renal aneurysm, endovascular treatment should be considered. With development of more flexible and low-profile endoprosthesis with accurate deployment, these have become more usable.

  9. Endovascular Treatment Strategies in Aortoiliac Occlusion

    SciTech Connect

    Ozkan, Ugur Oguzkurt, Levent Tercan, Fahri Gumus, Burcak

    2009-05-15

    The aim of this study was to report our experience in endovascular treatment of total aortoiliac occlusion. Five patients who underwent endovascular recanalization procedures including manual aspiration thrombectomy, balloon angioplasty, and stent placement for total aortoiliac occlusion in a 4-year period were reviewed retrospectively. The mean age of patients was 51 years (range, 43 to 58 years). All patients had abdominal aorta and bilateral common iliac artery occlusion with or without external iliac artery occlusion. All patients either had a contraindication to surgery or refused it. Initial technical success was obtained in four of five (80%) patients. Endovascular techniques were successful in four patients who had good distal runoff and short-segment aortoiliac occlusion, but failed in a patient who had the worst distal runoff and long-segment aortoiliac occlusion. We observed two major complications, one of which was bilateral rupture of the common iliac arteries treated with covered stent placement. Another patient had extension of intra-aortic thrombus into the iliac stent after primary stenting. This was successfully treated with manual aspiration thrombectomy. Aortic and iliac stents remained patent during the follow-up period (median, 18 months; range, 3 to 26 months) in four patients. Primary patency rates at 6, 12, and 24 months were all 80%. In conclusion, endovascular treatment can be an alternative for aortoiliac occlusion in selected patients. Short- to midterm follow-up so far is satisfactory. Removal of intra-aortic thrombus with manual aspiration thrombectomy before balloon angioplasty and/or stenting is possible and a good alternative to thrombolysis.

  10. Surveillance Imaging Following Endovascular Aneurysm Repair

    PubMed Central

    Pandey, Nirnimesh; Litt, Harold I.

    2015-01-01

    There is a significant risk of complication following endovascular abdominal repair (EVAR), including endoleak, graft translocation, thrombosis, and infection. Surveillance imaging is important for detecting EVAR complication. Surveillance modalities include conventional X-ray, computed tomography, magnetic resonance imaging, ultrasound, and conventional angiography, with inherent advantages and drawbacks to each modality. The authors present common complications following EVAR, and recent advances in the key modalities for surveillance. PMID:26327742

  11. Endovascular treatment of pediatric intracranial aneurysms: a retrospective study of 35 aneurysms.

    PubMed

    Takemoto, Koichiro; Tateshima, Satoshi; Golshan, Ali; Gonzalez, Nestor; Jahan, Reza; Duckwiler, Gary; Vinuela, Fernando

    2014-07-01

    Pediatric intracranial aneurysms are rare and not well characterized in comparison with those in adults. To analyze our institution's longitudinal experience of endovascular treatment for pediatric aneurysms to better understand this rare condition. A retrospective record review was performed of patients aged <20 years treated with endovascular methods for intracranial aneurysms between 1995 and 2012. There were 31 patients (average 14.4±4.2 years; 20 male, 11 female) with 35 intracranial aneurysms. The rate of subarachnoid hemorrhage as the initial presentation was 48% and the rates of multiple and giant aneurysms were 13% and 31%, respectively; 28.5% of the cases were posterior circulation aneurysms. Fifteen saccular aneurysms occurred in 14 patients and 17 fusiform aneurysms were noted in 14 patients. Two infectious aneurysms were diagnosed in two patients and one traumatic aneurysm occurred in another patient. Thirty-four aneurysms were treated endovascularly and one had thrombosed spontaneously on a follow-up angiogram. Of the 15 saccular aneurysms, 11 were treated with conventional coiling, one was treated with stent-assisted coiling, one was treated with a flow-diverting stent and two were treated with parent vessel occlusion (PVO). Of the 17 fusiform aneurysms, 15 were treated with PVO with or without prior bypass surgery and one was treated with a flow-diverting stent. The rate of permanent complications and a favorable outcome were 2.9% and 87%, respectively. Endovascular treatment of pediatric aneurysms is technically feasible with an acceptable complication rate despite the high incidence of fusiform aneurysms. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  12. Techniques for aortic arch endovascular repair.

    PubMed

    Hongku, Kiattisak; Dias, Nuno; Sonesson, Bjorn; Resch, Timothy

    2016-06-01

    This article reviews endovascular strategies for aortic arch repair. Open repair remains the gold standard particularly for good risk patients. Endovascular treatment potentially offers a less invasive repair. Principles, technical considerations, devices and outcomes of each technique are discussed and summarized. Hybrid repair combines less invasive revascularization options, instead of arch replacement while extending stent-graft into the arch. Outcomes vary with regard to extent of repair and aortic arch pathologies treated. Results of arch chimney and other parallel graft techniques perhaps make it a less preferable choice for elective cases. However, they are very appealing options for urgent or bailout situations. Fenestrated stent-grafting is subjected to many technical challenges in aortic arch due to difficulties in stent-graft orientation and fenestration positioning. In situ fenestration techniques emerge to avoid these problems, but durability of stent-grafts after fenestration and ischemic consequences of temporary carotid arteries coverage raises some concern total arch repair using this technique. Arch branched graft is a new technology. Early outcomes did not meet the expectation; however the results have been improving after its learning curve period. Refining stent-graft technologies and implantation techniques positively impact outcomes of endovascular approaches.

  13. Complications of endovascular treatment of cerebral aneurysms.

    PubMed

    Orrù, Emanuele; Roccatagliata, Luca; Cester, Giacomo; Causin, Francesco; Castellan, Lucio

    2013-10-01

    The number of neuroendovascular treatments of both ruptured and unruptured aneurysms has increased substantially in the last two decades. Complications of endovascular treatments of cerebral aneurysms are rare but can potentially lead to acute worsening of the neurological status, to new neurological deficits or death. Some of the possible complications, such as vascular access site complications or systemic side effects associated with contrast medium (e.g. contrast medium allergy, contrast induced nephropathy) can also be encountered in diagnostic angiography. The most common complications of endovascular treatment of cerebral aneurysms are related to acute thromboembolic events and perforation of the aneurysm. Overall, the reported rate of thromboembolic complications ranges between 4.7% and 12.5% while the rate of intraprocedural rupture of cerebral aneurysms is about 0.7% in patients with unruptured aneurysms and about 4.1% in patients with previously ruptured aneurysms. Thromboembolic and hemorrhagic complications may occur during different phases of endovascular procedures and are related to different technical, clinical and anatomic reasons. A thorough knowledge of the different aspects of these complications can reduce the risk of their occurrence and minimize their clinical sequelae. A deep understanding of complications and of their management is thus part of the best standard of care.

  14. Modification of an endovascular stent graft for abdominal aortic aneurysm

    NASA Astrophysics Data System (ADS)

    Moloye, Olajompo Busola

    Endovascular surgery is currently used to treat abdominal aortic aneurysms (AAA). A stent graft is deployed to exclude blood flow from the aneurysm sac. It is an effective procedure used in preventing aneurysm rupture, with reduced patient morbidity and mortality compared to open surgical repair. Migration and leakage around the device ("endoleak") due to poor sealing of the stent graft to the aorta have raised concerns about the long-term durability of endovascular repair. A preliminary study of cell migration and proliferation is presented as a prelude to a more extensive in vivo testing. A method to enhance the biological seal between the stent graft and the aorta is proposed to eliminate this problem. This can be achieved by impregnating the stent graft with 50/50 poly (DL-lactide co glycolic acid) (PLGA) and growth factors such as basic fibroblast growth factor (bFGF) or connective tissue growth factor (CTGF), at the proximal and distal ends. It is hypothesized that as PLGA degrades it will release the growth factors that will promote proliferation and migration of aortic smooth muscle cells to the coated site, leading to a natural seal between the aorta and the stent graft. In addition, growth factor release should promote smooth muscle cell (SMC) contraction that will help keep the stent graft in place at the proximal and distal ends. It is shown that a statistically significant effect of increased cell proliferation and migration is observed for CTGF release. Less of an effect is noted for bFGF or just the PLGA. The effect is estimated to be large enough to be clinically significant in a future animal study. The long term goal of this study is to reduce migration encounter after graft deployment and to reduce secondary interventions of EVAR especially for older patients who are unfit for open surgical treatment.

  15. Medical and endovascular management of critical limb ischemia.

    PubMed

    Lumsden, Alan B; Davies, Mark G; Peden, Eric K

    2009-04-01

    Critical limb ischemia (CLI) is the term used to designate the condition in which peripheral artery disease has resulted in resting leg or foot pain or in a breakdown of the skin of the leg or foot, causing ulcers or tissue loss. If not revascularized, CLI patients are at risk for limb loss and for potentially fatal complications from the progression of gangrene and the development of sepsis. The management of CLI requires a multidisciplinary team of experts in different areas of vascular disease, from atherosclerotic risk factor management to imaging, from intervention to wound care and physical therapy. In the past decade, the most significant change in the treatment of CLI has been the increasing tendency to shift from bypass surgery to less invasive endovascular procedures as first-choice revascularization techniques, with bypass surgery then reserved as backup if appropriate. The goals of intervention for CLI include the restoration of pulsatile, inline flow to the foot to assist wound healing, the relief of rest pain, the avoidance of major amputation, preservation of mobility, and improvement of patient function and quality of life. The evaluating physician should be fully aware of all revascularization options in order to select the most appropriate intervention or combination of interventions, while taking into consideration the goals of therapy, risk-benefit ratios, patient comorbidities, and life expectancy. We discuss the incidence, risk factors, and prognosis of CLI and the clinical presentation, diagnosis, available imaging modalities, and medical management (including pain and ulcer care, pharmaceutical options, and molecular therapies targeting angiogenesis). The endovascular approaches that we review include percutaneous transluminal angioplasty (with or without adjunctive stenting); subintimal angioplasty; primary femoropopliteal and infrapopliteal deployment of bare nitinol, covered, drug-eluting, or bioabsorbable stents; cryoplasty; excimer

  16. Reaction-Diffusion Model Simulations relevant to Modified Taylor-Couette Flow in Systems of Varying Length

    NASA Astrophysics Data System (ADS)

    Halmstad, Andrew; Olsen, Thomas; Wiener, Richard

    2006-11-01

    Previously, we have observed a period-doubling cascade to chaos in Modified Taylor-Couette Flow with Hourglass Geometry. Such behavior had been predicted by The Reaction-Diffusion model simulations. The chaotic formation of Taylor-Vortex pair formation was restricted to a very narrow band about the waist of the hourglass. It was suggested that with increasing lengths of systems, the chaotic region would expand. We present a battery of simulations to determine the variation of the size of the chaotic region with length, seeking the transition to spatio- temporal chaos. Richard J. Wiener et al, Phys. Rev. E 55, 5489 (1997). H. Riecke and H.-G. Paap, Europhys. Lett. 14, 1235 (1991).

  17. Endovascular Management of Delayed Complete Graft Thrombosis After Endovascular Aneurysm Repair

    SciTech Connect

    Thurley, Peter D.; Glasby, Michael J.; Pollock, John G.; Bungay, Peter; Nunzio, Mario De; El-Tahir, Amin M.; Quarmby, John W.

    2010-08-15

    Graft thrombosis rates after endovascular aneurysm repair (EVAR) of abdominal aortic aneurysms vary widely in published series. When thrombosis does occur, it usually involves a single limb and occurs within 3 months of stent-graft insertion. If the entire endoprosthesis is thrombosed, treatment may be challenging because femoro-femoral crossover graft insertion is not an option and a greater volume of thrombus is present, thus making thrombolysis more difficult. We present two cases of delayed thrombosis after EVAR involving the entire stent-graft. These were successfully treated by a combined surgical and endovascular technique, and patency has been maintained in both cases to date.

  18. Corticosteroid administration modifies ozone-induced increases in sheep airway blood flow

    SciTech Connect

    Gunther, R.A.; Yousef, M.A.; Schelegle, E.S.; Cross, C.E. )

    1992-09-01

    Recently, we have shown that exposure of intubated conscious sheep to 3 to 4 ppm ozone (O3) for 3 h increases bronchial blood flow (Qbr). The purpose of the present study was to assess the potential role of corticosteroids in modulating this increase. Six nasally intubated sheep were exposed to filtered room air, 3.5 ppm O3 on two separate occasions, and 3.5 ppm O3 plus methyl-prednisone, for 3 h. Qbr was measured using a chronically implanted 20 MHz pulsed Doppler flow probe. Qbr, mean aortic pressure, cardiac output, pulmonary artery pressure, arterial blood gases, and core temperature were monitored. After 3 h of 3.5 ppm O3, Qbr increased from 3.2 +/- 0.5 (mean +/- SEM) to 8.5 +/- 1.6 KHz, whereas bronchial vascular resistance (BVR) decreased from the baseline value of 43.6 +/- 8.0 to 15.0 +/- 3 mm Hg/KHz. With corticosteroids, baseline Qbr was 3.2 +/- 0.6 and BVR was 44.2 +/- 9.7; after 3 h of 3.5 ppm O3, Qbr was 3.3 +/- 0.5 KHz and BVR was 39.0 +/- 8.0 mm Hg/KHz. The two 3.5-ppm O3 exposures without corticosteroids were impressively reproducible. Except for Qbr and BVR, no other measured cardiovascular parameters were affected by O3. The results indicate that corticosteroids are capable of interfering with mediator, neurohumoral, or inflammatory cell mechanisms responsible for vasodilation of the airway microcirculation after O3 exposure, but do not specifically address the specific processes whereby this attenuation occurs.

  19. Particle Acceleration in a High Enthalpy Nozzle Flow with a Modified Detonation Gun

    NASA Astrophysics Data System (ADS)

    Henkes, C.; Olivier, H.

    2014-04-01

    The quality of thermal sprayed coatings depends on many factors which have been investigated and are still in scientific focus. Mostly, the coating material is inserted into the spray device as solid powder. The particle condition during the spray process has a strong effect on coating quality. In some cases, higher particle impact energy leads to improved coating quality. Therefore, a computer-controlled detonation gun based spraying device has been designed and tested to obtain particle velocities over 1200 m/s. The device is able to be operated in two modes based on different flow-physical principles. In one mode, the device functions like a conventional detonation gun in which the powder is accelerated in a blast wave. In the other mode, an extension with a nozzle transforms the detonation gun process into an intermittent shock tunnel process in which the particles are accelerated in a high enthalpy nozzle flow with high reservoir conditions. Presented are experimental results of the operation with nozzle in which the device generates very high particle velocities up to a frequency of 5 Hz. A variable particle injection system allows injection of the powder at any point along the nozzle axis to control particle temperature and velocity. A hydrogen/oxygen mixture is used in the experiments. Operation performance and nozzle outflow are characterized by time resolved pressure measurements. The particle conditions inside the nozzle and in the nozzle exit plane are calculated with a quasi-one-dimensional WENO-code of high order. For the experiments, particle velocity is obtained by particle image velocimetry, and particle concentration is qualitatively determined by a laser extinction method. The powders used are WC-Co(88/12), NiCr(80/20), Al2O3, and Cu. Different substrate/powder combinations for varying particle injection positions have been investigated by light microscopy and measurements of microhardness.

  20. Hyperdynamic sepsis modifies a PEEP-mediated redistribution in organ blood flows

    SciTech Connect

    Bersten, A.D.; Gnidec, A.A.; Rutledge, F.S.; Sibbald, W.J. )

    1990-05-01

    Changes in organ blood flow (Q) produced by 20 cm H2O positive end-expiratory pressure (PEEP) were measured before and after the induction of hyperdynamic sepsis in nine unanesthetized sheep. During the baseline nonseptic study, PEEP was associated with a 9% fall in thermodilution-measured systemic Q, although arterial perfusing pressures were unaffected. Concurrently, microsphere-derived Q was maintained to the brain and heart, but fell to liver, spleen, pancreas, kidney, large intestine, and gastrocnemius. Twenty-four to 36 h after cecal ligation and perforation, a pre-PEEP septic study demonstrated an increase in all of the cardiac index (CI) and systemic O2 delivery when compared with the nonseptic study, whereas whole-body O2 extraction was depressed. Although PEEP depressed systemic Q during the septic study to a greater extent than during the nonseptic study (p less than 0.02), absolute organ Q fell only to pancreas, liver, and spleen. Relative to the simultaneous fall in the CI, Q to some splanchnic organs was not depressed by PEEP to the same magnitude in the septic as in the nonseptic study. When an infusion of Ringer's lactate subsequently restored systemic Q to pre-PEEP septic levels, individual flows that had been depressed by PEEP were not restored. Furthermore, Q-kidney continued to fall, such that the postfluid Q-kidney (-19%) was significantly less than was demonstrated in the pre-PEEP septic study. We postulate that differences noted in the distribution of organ Q between the nonseptic and hyperdynamic septic studies after the application of PEEP were secondary to the vasculopathy of sepsis and/or an alteration in the function of specific organ microcirculations. However, these data do not address whether the changes in organ Q distribution after a PEEP-mediated depression in systemic Q during sepsis significantly restricted tissue DO2.

  1. Glucose monitoring using a polymer brush modified polypropylene hollow fiber-based hydraulic flow sensor.

    PubMed

    Fortin, Nicolas; Klok, Harm-Anton

    2015-03-04

    Tight regulation of blood glucose levels of diabetic patients requires durable and robust continuous glucose sensing schemes. This manuscript reports the fabrication of ultrathin, phenylboronic acid (PBA) functionalized polymer brushes that swell upon glucose binding and which were integrated as the sensing interface in a new polypropylene hollow fiber (PPHF)-based hydraulic flow glucose sensor prototype. The polymer brushes were prepared via surface-initiated atom transfer radical polymerization of sodium methacrylate followed by postpolymerization modification with 3-aminophenyl boronic acid. In a first series of experiments, the glucose-response of PBA-functionalized poly(methacrylic acid) (PMAA) brushes grafted from planar silicon surfaces was investigated by quartz crystal microbalance with dissipation (QCM-D) and atomic force microscopy (AFM) experiments. The QCM-D experiments revealed a more or less linear change of the frequency shift for glucose concentrations up to ∼10 mM and demonstrated that glucose binding was completely reversible for up to seven switching cycles. The AFM experiments indicated that glucose binding was accompanied by an increase in the film thickness of the PBA functionalized PMAA brushes. The PBA functionalized PMAA brushes were subsequently grafted from the surface of PPHF membranes. The hydraulic permeability of these porous fibers depends on the thickness and swelling of the PMAA brush coating. PBA functionalized brush-coated PPHFs showed a decrease in flux upon exposure to glucose, which is consistent with swelling of the brush coating. Because they avoid the use of enzymes and do not rely on an electrochemical transduction scheme, these PPHF-based hydraulic flow sensors could represent an interesting alternative class of continuous glucose sensors.

  2. Speciation of mercury by hydrostatically modified electroosmotic flow capillary electrophoresis coupled with volatile species generation atomic fluorescence spectrometry.

    PubMed

    Yan, Xiu-Ping; Yin, Xue-Bo; Jiang, Dong-Qing; He, Xi-Wen

    2003-04-01

    A novel method for speciation analysis of mercury was developed by on-line hyphenating capillary electrophoresis (CE) with atomic fluorescence spectrometry (AFS). The four mercury species of inorganic mercury Hg(II), methymercury MeHg(I), ethylmercury EtHg(I), and phenylmercury PhHg(I) were separated as mercury-cysteine complexes by CE in a 50-cm x 100-microm-i.d. fused-silica capillary at 15 kV and using a mixture of 100 mmol L(-1) of boric acid and 12% v/v methanol (pH 9.1) as electrolyte. A novel technique, hydrostatically modified electroosmotic flow (HSMEOF) in which the electroosmotic flow (EOF) was modified by applying hydrostatical pressure opposite to the direction of EOF was used to improve resolution. A volatile species generation technique was used to convert the mercury species into their respective volatile species. A newly developed CE-AFS interface was employed to provide an electrical connection for stable electrophoretic separations and to allow on-line volatile species formation. The generated volatile species were on-line detected with AFS. The precisions (RSD, n = 5) were in the range of 1.9-2.5% for migration time, 1.8-6.3% for peak area response, and 2.3-6.1% for peak height response for the four mercury species. The detection limits ranged from 6.8 to 16.5 microg L(-1) (as Hg). The recoveries of the four mercury species in the water samples were in the range of 86.6-111%. The developed technique was successfully applied to speciation analysis of mercury in a certified reference material (DORM-2, dogfish muscle).

  3. A mathematical model of endovascular heat transfer for human brain cooling

    NASA Astrophysics Data System (ADS)

    Salsac, Anne-Virginie; Lasheras, Juan Carlos; Yon, Steven; Magers, Mike; Dobak, John

    2000-11-01

    Selective cooling of the brain has been shown to exhibit protective effects in cerebral ischemia, trauma, and spinal injury/ischemia. A multi-compartment, unsteady thermal model of the response of the human brain to endovascular cooling is discussed and its results compared to recent experimental data conducted with sheep and other mammals. The model formulation is based on the extension of the bioheat equation, originally proposed by Pennes(1) and later modified by Wissler(2), Stolwijk(3) and Werner and Webb(4). The temporal response of the brain temperature and that of the various body compartments to the cooling of the blood flowing through the common carotid artery is calculated under various scenarios. The effect of the boundary conditions as well as the closure assumptions used in the model, i.e. perfusion rate, metabolism heat production, etc. on the cooling rate of the brain are systematically investigated. (1) Pennes H. H., “Analysis of tissue and arterial blood temperature in the resting forearm.” J. Appl. Physiol. 1: 93-122, 1948. (2) Wissler E. H., “Steady-state temperature distribution in man”, J. Appl. Physiol., 16: 764-740, 1961. (3) Stolwick J. A. J., “Mathematical model of thermoregulation” in “Physiological and behavioral temperature regulation”, edited by J. D. Hardy, A. P. Gagge and A. J. Stolwijk, Charles C. Thomas Publisher, Springfiels, Ill., 703-721, 1971. (4) Werner J., Webb P., “A six-cylinder model of human thermoregulation for general use on personal computers”, Ann. Physiol. Anthrop., 12(3): 123-134, 1993.

  4. Determination of Diclofenac on a Dysprosium Nanowire- Modified Carbon Paste Electrode Accomplished in a Flow Injection System by Advanced Filtering

    PubMed Central

    Daneshgar, Parandis; Norouzi, Parviz; Ganjali, Mohammad Reza; Dinarvand, Rasoul; Moosavi-Movahedi, Ali Akbar

    2009-01-01

    A new detection technique called Fast Fourier Transform Square-Wave Voltammetry (FFT SWV) is based on measurements of electrode admittance as a function of potential. The response of the detector (microelectrode), which is generated by a redox processes, is fast, which makes the method suitable for most applications involving flowing electrolytes. The carbon paste electrode was modified by nanostructures to improve sensitivity. Synthesized dysprosium nanowires provide a more effective nanotube-like surface [1-4] so they are good candidates for use as a modifier for electrochemical reactions. The redox properties of diclofenac were used for its determination in human serum and urine samples. The support electrolyte that provided a more defined and intense peak current for diclofenac determination was a 0.05 mol L−1 acetate buffer pH = 4.0. The drug presented an irreversible oxidation peak at 850 mV vs. Ag/AgCl on a modified nanowire carbon paste electrode which produced high current and reduced the oxidation potential by about 100 mV. Furthermore, the signal-to-noise ratio was significantly increased by application of a discrete Fast Fourier Transform (FFT) method, background subtraction and two-dimensional integration of the electrode response over a selected potential range and time window. To obtain the much sensivity the effective parameters such as frequency, amplitude and pH was optimized. As a result, CDL of 2.0 × 10−9 M and an LOQ of 5.0 × 10−9 M were found for the determination for diclofenac. A good recovery was obtained for assay spiked urine samples and a good quantification of diclofenac was achieved in a commercial formulation. PMID:22408485

  5. A modified hood infiltrometer to estimate the soil hydraulic properties from the transient water flow measurements

    NASA Astrophysics Data System (ADS)

    Moret-Fernández, D.; González-Cebollada, C.; Latorre, B.; Pérez, V.

    2015-11-01

    In-situ measurements of soil hydraulic properties on covered soil surfaces (i.e. vegetated or residue covered surfaces) are of paramount importance in many agronomic or hydrological researches. These soil parameters are commonly estimated with the tension infiltrometry technique. This paper presents a portable and modified design of the hood infiltrometer (MHI) that, unlike to the original hood infiltrometer, allows estimating the soil hydraulic properties from the transient cumulative infiltration curve. The MHI consists of a water-supply reservoir attaches to a hat-shaped base placed on the soil surface. The base of the hat is closed by a system of sticks and a malleable material ring. To test the viability of this new design, the hydraulic conductivity (Ks) estimated with MHI in a loam soil using the multiple head approach was compared to the corresponding values calculated from the transient infiltration curve analysis. Next, the MHI was tested on three different soils at saturated conditions, and the sorptivity (S) and Ks estimated by the transient infiltration curve analysis were compared to the corresponding values obtained with a disc infiltrometer (DI). An additional field experiment was performed to compare the hydraulic properties measured with MHI on a bare soil and a soil covered with plants. Results demonstrated that this design allows hermetically closing the base of the hat without disturbing the soil surface. The Ks estimated with the multiple head approach was not statistically different (p = 0.61) to that obtained with the transient infiltration curve analysis. No significant differences between the Ks (p = 0.66) and S (p = 0.50) values estimated with DI and MHI were observed. The S values measured with MHI on the covered soil surface were significantly higher than that measured on the adjacent bare soil. These results indicate that MHI can be a viable alternative to estimate the hydraulic properties of covered soils from the measured transient

  6. Challenging neck anatomy is associated with need for intraoperative endovascular adjuncts during endovascular aortic aneurysm repair (EVAR).

    PubMed

    Grisafi, Joseph L; Rahbar, Rodeen; Nelms, Justin; Detschelt, Elizabeth L; Chess, Bart A; Benckart, Daniel H; Muluk, Satish C

    2011-08-01

    The purpose of this study was to determine which proximal seal zone characteristics were predictive of early and late type Ia endoleak development after endovascular aortic aneurysm repair (EVAR) for infrarenal abdominal aortic aneurysmal disease. We evaluated 146 patients who underwent EVAR between January 2006 and March 2007. In the cohort, high-resolution computed tomography images of 100 (68.5%) patients were available, which showed detailed measurement of proximal neck parameters, including diameter, length, calcification, thrombus, suprarenal and infrarenal angles, and reverse taper morphology. Postprocessing of digital data sets was performed to obtain centerline-of-flow measurements. Relevant medical records and follow-up computed tomography scans were reviewed. Mean age of the patients was 72.7 years, with 78% being male. Of these patients, 66% did not satisfy the instructions for use for the Zenith EVAR device, and 50% did not satisfy the instructions for use for the AneuRx device. Nine patients had intraoperative type Ia endoleaks. A 100% assisted primary technical success rate was achieved with the adjunctive use of angioplasty (n = 4), uncovered stent (n = 3), and extension cuff (n = 2) placement. There was a significant association between type Ia endoleak development and magnitude of the infrarenal angle (p < 0.01); however, other parameters were not significant. At follow-up (mean, 587 days), no patient had a type Ia endoleak, and there were no aneurysm-related deaths. Our data indicate that infrarenal angle is related to intraoperative type Ia endoleak occurrence, but other factors often thought to be indicative of adverse neck anatomy are not significant predictors. Moreover, all type Ia endoleaks in this cohort were successfully eliminated intraoperatively, and durability was confirmed on postoperative surveillance. These data demonstrate that challenging neck anatomy is associated with the need for intraoperative endovascular adjuncts, and that

  7. A Modified Through-Flow Wave Rotor Cycle with Combustor Bypass Ducts

    NASA Technical Reports Server (NTRS)

    Paxson Daniel E.; Nalim, M. Razi

    1998-01-01

    A wave rotor cycle is described which avoids the inherent problem of combustor exhaust gas recirculation (EGR) found in four-port, through-flow wave rotor cycles currently under consideration for topping gas turbine engines. The recirculated hot gas is eliminated by the judicious placement of a bypass duct which transfers gas from one end of the rotor to the other. The resulting cycle, when analyzed numerically, yields an absolute mean rotor temperature 18% below the already impressive value of the conventional four-port cycle (approximately the turbine inlet temperature). The absolute temperature of the gas leading to the combustor is also reduced from the conventional four-port design by 22%. The overall design point pressure ratio of this new bypass cycle is approximately the same as the conventional four-port cycle. This paper will describe the EGR problem and the bypass cycle solution including relevant wave diagrams. Performance estimates of design and off-design operation of a specific wave rotor will be presented. The results were obtained using a one-dimensional numerical simulation and design code.

  8. Solution Concentration and Flow Rate of Fe3+-modified Porphyrin (Red Blood Model) on Giant Magnetoresistance (GMR) Sensor Efficiency

    NASA Astrophysics Data System (ADS)

    Aminudin, A.; Tjahyono, D. H.; Suprijadi; Djamal, M.; Zaen, R.; Nandiyanto, A. B. D.

    2017-03-01

    Red blood has been of great interest for scientists since it relates to human’ and living creature’s life sustainability. One of the important compounds in red blood is porphyrin. Here, the purpose of this study was to develop a method for detecting porphyrin concentration using the assistance of giant magnetoresistance. In short of the method, we added Fe3+ solution to the porphyrin, and the mixed solution was introduced to the magnetic field. Next, the magnetized solution was introduced to the magnetic sensor to indicate the existence of porphyrin in the solution. To confirm the effectiveness of our method in detecting porphyrin, we varied the flow rate and concentration of Fe3+-modified porphyrin solution. The result showed that the more concentration and the slower flow rate affected the higher sensitivity gained. Since this developed method is simple but effective for detecting porphyrin concentration, we believe that further development of this method will be benefit for many applications, specifically relating to the medical uses.

  9. Biosensing of glucose in flow injection analysis system based on glucose oxidase-quantum dot modified pencil graphite electrode.

    PubMed

    Sağlam, Özlem; Kızılkaya, Bayram; Uysal, Hüseyin; Dilgin, Yusuf

    2016-01-15

    A novel amperometric glucose biosensor was proposed in flow injection analysis (FIA) system using glucose oxidase (GOD) and Quantum dot (ZnS-CdS) modified Pencil Graphite Electrode (PGE). After ZnS-CdS film was electrochemically deposited onto PGE surface, GOD was immobilized on the surface of ZnS-CdS/PGE through crosslinking with chitosan (CT). A pair of well-defined reversible redox peak of GOD was observed at GOD/CT/ZnS-CdS/PGE based on enzyme electrode by direct electron transfer between the protein and electrode. Further, obtained GOD/CT/ZnS-CdS/PGE offers a disposable, low cost, selective and sensitive electrochemical biosensing of glucose in FIA system based on the decrease of the electrocatalytic response of the reduced form of GOD to dissolved oxygen. Under optimum conditions (flow rate, 1.3mL min(-1); transmission tubing length, 10cm; injection volume, 100μL; and constant applied potential, -500mV vs. Ag/AgCl), the proposed method displayed a linear response to glucose in the range of 0.01-1.0mM with detection limit of 3.0µM. The results obtained from this study would provide the basis for further development of the biosensing using PGE based FIA systems. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Endovascular Management of Long-Segmental Petrocavernous Internal Carotid Artery (Carotid S) Occlusion

    PubMed Central

    Park, Soonchan; Park, Eun Suk; Kwak, Jae Hyuk; Lee, Dong-Geun; Suh, Dae Chul; Kwon, Sun U.; Lee, Deok Hee

    2015-01-01

    Background and Purpose Long-segmental thrombotic occlusion of the distal internal carotid artery (ICA) sparing the cervical segment proximally and the supraclinoid segment distally, which could be termed ’Carotid S occlusion’, has an unusual clinical presentation. However, endovascular management of this lesion is challenging. The purpose of our study is to report our endovascular treatment clinical experience of the disease. Methods From March 2008 to June 2013, we could identify 14 patients (average age: 62.1, median age: 62, range: 50-79) with ‘Carotid S occlusion’, who underwent endovascular recanalization procedures. Patient’s clinical presentations were collected and the imaging findings also analyzed. The technical success rate, 24-hour and follow-up imaging outcome, and the clinical outcome using the 90-day mRS (modified Rankin scale) score were evaluated. Results Patients presented with gradually progressing (n = 8), fluctuating (n = 3), transient ischemic attack (n = 2) and stationary (n = 1) symptoms. DWI showed internal and external border-zone lesions in six patients, only internal ICA border-zone lesions in three patients, and only external border-zone lesions in two patients. Underlying distal ICA stenosis was noted in 12 patients. The technical success rate was 92.8% (13/14). Luminal patency was noted in all patients (100%) after 24 hours and in nine of 10 (90%) on long-term follow-up (median: 6.5, average: 15.1, range: 1-39 months). A 90-day, good functional outcome (mRS ≤ 2) was noted in 13 of 14 patients (92.8%). Conclusions ‘Carotid S occlusion’ usually presented with border-zone infarction and endovascular management of the lesions was feasible. A relatively successful clinical outcome could be achieved after successful revascularization. PMID:26437999

  11. 21 CFR 870.3460 - Endovascular Suturing System.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Endovascular Suturing System. 870.3460 Section 870.3460 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3460 Endovascular...

  12. 21 CFR 870.3460 - Endovascular Suturing System.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Endovascular Suturing System. 870.3460 Section 870.3460 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3460 Endovascular...

  13. 21 CFR 870.3460 - Endovascular Suturing System.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Endovascular Suturing System. 870.3460 Section 870.3460 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3460 Endovascular...

  14. Endovascular Repair of a Blunt Abdominal Aortic Injury

    PubMed Central

    Tobler, William D.; Tan, Tze-Woei; Farber, Alik

    2012-01-01

    Blunt abdominal aortic injury is an uncommon traumatic finding. In the past, treatment options have traditionally consisted of open operative repair; however, the development of endovascular surgery has created new interventional possibilities. This case is presented to demonstrate the applications of endovascular abdominal aortic repair for a blunt traumatic injury. PMID:23730142

  15. [Endovascular and surgical associated treatment of post-traumatic epistaxis].

    PubMed

    Rydzewski, Bogdan; Juszkat, Robert; Matusiak, Monika; Zarzecka, Małgorzata Anna

    2008-01-01

    We report on two cases of patients, in whom endovascular embolization of the maxillary artery and next surgical ligation of the anterior ethmoidal artery was performed due to posttraumatic intracrable epistaxis. In those patients, conservative treatment failed, hence endovascular embolization was made. Due to persisted bleeding, right anterior ethmoidal artery were surgically ligated in both patients. After the procedures, bleeding completely stopped.

  16. Endovascular exclusion of a large external iliac vein aneurysm.

    PubMed

    Todorov, Mina; Hernandez, Diego

    2013-07-01

    Iliac vein aneurysms are uncommon, and there is no consensus on optimal treatment. We present a case of venous exclusion using an endovascular approach. To our knowledge, this is the first reported case of a large external iliac vein aneurysm treated endovascularly. We have demonstrated the feasibility of this approach with satisfactory 1-year follow-up. Copyright © 2013. Published by Elsevier Inc.

  17. Complications of Endovascular Repair of Abdominal Aortic Aneurysms: A Review

    SciTech Connect

    Katzen, Barry T. MacLean, Alexandra A.

    2006-12-15

    The endovascular procedure for repair of abdominal aortic aneurysms has had an enormous impact on the treatment of this challenging disease. Complications, however, do occur and it is important to have a thorough understanding of the array of complications and appropriate management strategies. In this review of endovascular complications, we describe early and late complications paying particular attention to preventive, treatment and surveillance strategies.

  18. Lubricant jet flow phenomena in spur and helical gears with modified center distances and/or addendums for out-of-mesh conditions

    NASA Technical Reports Server (NTRS)

    Akin, L. S.; Townsend, D. P.

    1983-01-01

    Out-of-mesh jet lubrication of gears was examined. The pinion impingement cycle was described briefly. An analysis was developed for the lubricant jet flow in the out-of-mesh condition. The analysis provides for the inclusion of modified center distances and modified addendums. Equations were generated for the limit values of variables necessary to remove the severe limitations to facilitate computer analysis. A computer program was designed using these limit formulas to prevent negative impingement (missing) on the pinion.

  19. Lubricant jet flow phenomena in spur and helical gears with modified center distances and/or addendums - For out-of-mesh conditions

    NASA Technical Reports Server (NTRS)

    Akin, L. S.; Townsend, D. P.

    1985-01-01

    Out-of-mesh jet lubrication of gears was examined. The pinion impingement cycle was described briefly. An analysis was developed for the lubricant jet flow in the out-of-mesh condition. The analysis provides for the inclusion of modified center distances and modified addendum. Equations were generated for the limit values of variables necessary to remove the severe limitations to facilitate computer analysis. A computer program was designed using these limit formulas to prevent negative impingement (missing) on the pinion.

  20. Characterization of aggregates of surface modified fullerenes by asymmetrical flow field-flow fractionation with multi-angle light scattering detection.

    PubMed

    Astefanei, Alina; Kok, Wim Th; Bäuerlein, Patrick; Núñez, Oscar; Galceran, Maria Teresa; de Voogt, Pim; Schoenmakers, Peter J

    2015-08-21

    Fullerenes are carbon nanoparticles with widespread biomedical, commercial and industrial applications. Attributes such as their tendency to aggregate and aggregate size and shape impact their ability to be transported into and through the environment and living tissues. Knowledge of these properties is therefore valuable for their human and environmental risk assessment as well as to control their synthesis and manufacture. In this work, asymmetrical flow-field flow fractionation (AF4) coupled to multi-angle light scattering (MALS) was used for the first time to study the size distribution of surface modified fullerenes with both polyhydroxyl and carboxyl functional groups in aqueous solutions having different pH (6.5-11) and ionic strength values (0-200mM) of environmental relevance. Fractionation key parameters such as flow rates, flow programming, and membrane material were optimized for the selected fullerenes. The aggregation of the compounds studied appeared to be indifferent to changes in solution pH, but was affected by changes in the ionic strength. Polyhydroxy-fullerenes were found to be present mostly as 4nm aggregates in water without added salt, but showed more aggregation at high ionic strength, with an up to 10-fold increase in their mean hydrodynamic radii (200mM), due to a decrease in the electrostatic repulsion between the nanoparticles. Carboxy-fullerenes showed a much stronger aggregation degree in water (50-100nm). Their average size and recoveries decreased with the increase in the salt concentration. This behavior can be due to enhanced adsorption of the large particles to the membrane at high ionic strength, because of their higher hydrophobicity and much larger particle sizes compared to polyhydroxy-fullerenes. The method performance was evaluated by calculating the run-to-run precision of the retention time (hydrodynamic radii), and the obtained RSD values were lower than 1%. MALS measurements showed aggregate sizes that were in good

  1. Sodium Taurocholate Modifies the Bile Acid-Independent Fraction of Canalicular Bile Flow in the Rhesus Monkey

    PubMed Central

    Baker, Alfred L.; Wood, R. A. B.; Moossa, A. R.; Boyer, James L.

    1979-01-01

    Bile acid-independent secretion and the choleretic response to taurocholate were determined in rhesus monkeys fitted with indwelling silastic cannulas in the common bile ducts. Bile acids were infused intravenously in random order at 3.5, 7.0, or 10.5 μmol/min for 1.5 h each. When data were analyzed with a single regression line, bile flow increased in proportion to the level of bile acid secretion, although the y-intercepts (the conventional measurement of bile acid-independent secretion) varied widely (77.9±40.9 ml/24 h). The variation in y-intercepts was observed between animals and with repeated studies in the same animal and could not be explained by sex differences or the effects of the indwelling silastic cannulas, but seemed to be related to the order of bile acid infusion. With only two taurocholic acid infusion rates (7.0 and 3.5 μmol/min), [14C]erythritol clearance was greater per mole of secreted bile acid when the initial bile acid infusion was at the high level, but approached zero at low bile acid secretion rates, which suggests that so-called bile acid-independent canalicular flow is closely related to bile acid secretion or is small in size. The augmentation in [14C]erythritol clearance when the high infusion rate was given first was also associated with an increase in biliary clearance of [3H]inulin, which indicates that the premeability to inulin was also enhanced. Identical experiments which substituted equimolar infusions of a nonmicelle-forming bile acid (taurodehydrocholate) for taurocholate failed to demonstrate any difference in choleretic response or biliary clearance of [3H]inulin with the order of bile acid infusion. These experiments demonstrate that a micelleforming bile acid, taurocholate, can increase the permeability of the biliary system to large molecular weight solutes and simultaneously modify the y-intercept and the volume of bile secreted in response to the transported bile acid. Taurocholate may, therefore, modify its own

  2. Endovascular internal carotid artery trapping for ruptured blood blister-like aneurysms: long-term results from a single centre.

    PubMed

    Kim, Byong-Cheol; Kwon, O-Ki; Oh, Chang Wan; Bang, Jae Seung; Hwang, Gyojun; Jin, Sung-Chul; Park, Hyun

    2014-03-01

    Endovascular internal carotid artery (ICA) trapping was performed to treat ruptured blood blister-like aneurysms (BBAs). The aim of this study was to evaluate the procedural risks and long-term follow-up results. The records of 11 consecutive patients with BBAs who underwent endovascular ICA trapping between 2005 and 2010 were reviewed. Clinical outcomes were assessed with modified Rankin Scale (mRS) scores. Endovascular ICA trapping was performed in 11 patients as either the primary treatment (7 patients) or the secondary treatment (4 patients) after the patient underwent other treatments. Three patients underwent superficial temporal artery (STA)-middle cerebral artery (MCA) bypass when balloon test occlusion (BTO) revealed inadequate collateral circulation. In the primary ICA trapping group (seven patients), six patients had good outcomes (mRS 0 in five, mRS 1 in one), and one patient had a poor outcome (mRS 6: dead). In the secondary ICA trapping group (four patients), two patients had good outcomes (mRS 0), and two patients had poor outcomes (mRS 4, 5). All ten of the surviving patients were clinically stable during the follow-up period (mean 39 months). A radiological follow-up of nine patients (mean 22 months) demonstrated stable occlusion, with the exception of one reopening of the ICA because of coil migration. Perfusion studies of nine patients (mean: 23 months) demonstrated no perfusion decrease. Endovascular ICA trapping is an effective and durable treatment for BBAs.

  3. Multimodal endovascular management of acute ischemic stroke in patients over 75 years old is safe and effective.

    PubMed

    Ghobrial, George M; Chalouhi, Nohra; Rivers, Lana; Witte, Samantha; Davanzo, Justin; Dalyai, Richard; Gardecki, Michelle L; Jabbour, Pascal; Gonzalez, Fernando; Dumont, Aaron S; Rosenwasser, Robert H; Tjoumakaris, Stavropoula

    2013-05-01

    Greater attention has been directed to endovascular recanalization of acute ischemic stroke in septuagenarians and above. A retrospective chart review was conducted to include patients treated for acute ischemic stroke from 2006 to 2012. All patients underwent initial neurological assessment and non-contrast head CT. Patients treated from 2009 to 2012 additionally received emergent CT angiogram and CT perfusion. 51 patients met the clinical and radiographic criteria and underwent multimodal endovascular revascularization for acute ischemic events. All patients underwent cerebral angiography and met angiographic criteria for endovascular thrombolysis. 34 patients (67%) were older than 80 years of age. 23 patients (45%) received intravenous tissue plasminogen activator prior to admission. Eight (16%) patients underwent stent placement after intra-arterial thrombolysis, 10 (20%) underwent balloon angioplasty and seven (14%) underwent both angioplasty and stent placement. 21 (41%) required only intra-arterial thrombolytics. An improvement in Thrombolysis in Myocardial Infarction score was noted in 34 patients (67%). The average modified Rankin Scale score on discharge was 3.9. Symptomatic intracranial hemorrhage occurred in three patients (6%); none required surgery. One patient (1.9%) had a postoperative retroperitoneal hematoma, which was managed conservatively. Two fatalities resulted from intraoperative vessel rupture (3.9%), with a combined morbidity and mortality of 27.5%. Multimodal endovascular recanalization of acute ischemic stroke is a relatively safe treatment option in patients older than 75 years of age. Careful patient selection by clinical and radiographic inclusion criteria is necessary for the successful management of stroke in this age group.

  4. Sensor Fish Characterization of Fish Passage Conditions through John Day Dam Spillbay 20 with a Modified Flow Deflector

    SciTech Connect

    Duncan, Joanne P.

    2011-04-29

    Fish passage conditions over a modified deflector in Spillbay 20 at John Day Dam were evaluated by Pacific Northwest National Laboratory for the U.S. Army Corps of Engineers (USACE), Portland District, using Sensor Fish devices. The objectives of the study were to describe and compare passage exposure conditions at two spill discharges, 2.4 and 4.0 thousand cubic feet per second (kcfs), identifying potential fish injury regions within the routes, and to evaluate a low-tailwater condition at the 2.4-kcfs discharge. The study was performed in April 2010 concurrent with HI-Z balloon-tag studies by Normandeau Associates, Inc. Sensor Fish data were analyzed to estimate 1) exposure conditions, particularly exposure to severe collision and shear events; 2) differences in passage conditions between treatments; and 3) relationships to live-fish injury and mortality data estimates. Nearly all Sensor Fish significant events were classified as collisions; the most severe occurred at the gate, on the spillbay chute, or at the deflector transition. Collisions in the gate region were observed only during the 2.4-kcfs discharge, when the tainter gate was open 1.2 ft. One shear event was observed during the evaluation, occurring at the deflector transition during passage at the 2.4-kcfs discharge at low tailwater. Flow quality, computed using the Sensor Fish turbulence index, was best for passage at the low-flow low-tailwater condition as well. The worst flow quality was observed for the 4.0-kcfs test condition. Contrasting the passage exposure conditions, the 2.4-kcfs low-tailwater treatment would be most deleterious to fish survival and well-being.

  5. Amino-silica modified Nafion membrane for vanadium redox flow battery

    NASA Astrophysics Data System (ADS)

    Lin, Chien-Hong; Yang, Ming-Chien; Wei, Hwa-Jou

    2015-05-01

    A hybrid membrane of Nafion/amino-silica (amino-SiO2) for vanadium redox flow battery (VRB) systems is prepared via the sol-gel method to improve the selectivity of the Nafion membrane, to reduce the crossover of vanadium ions, and to decrease water transfer across the membranes. The sulfonated pores of the pristine Nafion membrane are filled with amino-SiO2 nanoparticles localized by electrostatic interaction. The permeability of vanadium ions through the Nafion/amino-SiO2 hybrid membrane is determined by electrometric titration. The results indicate the crossover of vanadium ions through the hybrid membrane is 26.8% of the pristine Nafion membrane. The presence of amino-SiO2 in the hybrid membrane is verified by X-ray photoelectron spectroscopy (XPS). Nafion/amino-SiO2 hybrid membrane exhibits through plane conductivity about the same as the pristine Nafion membrane. The ion exchange capacity (IEC) of the hybrid membrane is 9.4% higher than that of the pristine Nafion membrane. In addition, Nafion/amino-SiO2 hybrid membrane exhibits a higher coulombic efficiency (CE), voltage efficiency (VE), and energy efficiency (EE) over a range of current densities from 20 to 80 mA cm-2. The performance of VRB with Nafion/amino-SiO2 hybrid membrane varies little around a charge-discharge current density of 80 mA cm-2 for 150 cycles. Thus, the Nafion/amino-SiO2 hybrid membrane can suppress the vanadium ions crossover in VRB.

  6. Flow uncertainty from hurricane rain forecasted patterns obtained using a modified multivariable radar tracking technique

    NASA Astrophysics Data System (ADS)

    Corzo P, G. A.; Marquez, O.

    2012-04-01

    Different cities around Central and North American countries suffer from lack of spatial data as well as from hurricane induced floods. This paper extends a technique to project radar information into neighbor regions where the radar doesn't reach. To be able to use the precipitation patterns obtained from these projections in a flood forecasting system, it is required to know the uncertainty of such patterns. This is even more important when the region is prone to hurricanes. The hurricanes are highly dynamic and complex phenomena that commonly spread its influence in cyclic patterns. This work explores the use of projected spatial patterns of the hurricane Arlene (Category 2) from day 29 to 30 June in the basin of the Santa Catarina River in Mexico. The tracking is done by displacing the precipitation patterns in space using a data driven model (e.g. Neural Netwok). The decay of mass in the projection of hurricane event was calculated with a multivariable mixture of experts' model, using the cumulative change in mass of the whole radar information at previous time steps. A comparative analysis between the statistical distribution from a hydrological model and the built hurricane reconstructed patterns was performed. The HEC-HMS and HEC_RAS model was used for the analysis of the hydrology of the region and the uncertainty associated with the use of each possible projected result. Hourly simulations of the model during june 29th till july 1st were evaluated. The technique presented is very useful to identify possible sensitivity patterns from the hurricane behaviors as well as the most important ranges of flows expected in the hurricane event.

  7. [Endovascular stroke treatment following recent positive clinical trials].

    PubMed

    Thomalla, G; Fiehler, J

    2016-04-01

    Recently, five independent randomized controlled clinical trials demonstrated the efficacy and safety of endovascular stroke treatment in stroke patients with occlusion of proximal intracranial arteries. The five trials MR CLEAN, ESCAPE, EXTEND-IA, SWIFT-PRIME and REVASCAT randomized a total of 1287 stroke patients to either standard treatment, which in the majority of patients consisted of intravenous thrombolysis within 4.5 h of symptom onset or additional endovascular stroke treatment. In all the studies endovascular treatment resulted in a better clinical outcome with an odds ratio for a better clinical outcome 90 days after stroke ranging between 1.7 and 3.1 and an absolute increase in the proportion of patients with functionally independent outcome between 14% and 31%. The overwhelming benefit of endovascular treatment mainly results from mechanical thrombectomy using stent retriever devices and starting endovascular treatment within 6 h of symptom onset in stroke patients.

  8. Simulation and augmented reality in endovascular neurosurgery: lessons from aviation.

    PubMed

    Mitha, Alim P; Almekhlafi, Mohammed A; Janjua, Major Jameel J; Albuquerque, Felipe C; McDougall, Cameron G

    2013-01-01

    Endovascular neurosurgery is a discipline strongly dependent on imaging. Therefore, technology that improves how much useful information we can garner from a single image has the potential to dramatically assist decision making during endovascular procedures. Furthermore, education in an image-enhanced environment, especially with the incorporation of simulation, can improve the safety of the procedures and give interventionalists and trainees the opportunity to study or perform simulated procedures before the intervention, much like what is practiced in the field of aviation. Here, we examine the use of simulators in the training of fighter pilots and discuss how similar benefits can compensate for current deficiencies in endovascular training. We describe the types of simulation used for endovascular procedures, including virtual reality, and discuss the relevant data on its utility in training. Finally, the benefit of augmented reality during endovascular procedures is discussed, along with future computerized image enhancement techniques.

  9. Woven Endobridge (WEB) device for endovascular treatment of complex unruptured aneurysms-a single center experience.

    PubMed

    Lescher, Stephanie; du Mesnil de Rochemont, Richard; Berkefeld, Joachim

    2016-04-01

    The introduction of the Woven Endobridge (WEB) device increases the feasibility of endovascular treatment of wide-neck bifurcation aneurysms with limitations given by currently available sizes and shapes of the device. Parallel to other studies, we used the new device for selected patients who were no optimal candidates for established techniques like neurosurgical clipping or endovascular coiling. We aimed to report the angiographic and clinical results of WEB implantations or combinations between WEB and coiling or intracranial stents. We reviewed the records of n = 23 interventions in 22 patients with unruptured wide-neck aneurysms (UIA) who were assigned for aneurysm treatment with the use of the WEB or adjunctive techniques. Interventional procedures and clinical and angiographic outcomes are reported for the periprocedural phase and in mid-term FU. Of the included 22 patients, six patients needed additional coiling, intracranial stenting, or implantation of a flow diverter. WEB implantation was technically feasible in 22 out of the 23 interventions. Follow-up angiographic imaging proved total or subtotal occlusion of the aneurysm in 19 of 22 cases. Two minor recurrences remained stable during a period of 15 months. One patient with a partially thrombosed giant MCA aneurysm had a major recurrence and was retreated with a second WEB in combination with coiling. Despite of unfavorable anatomic conditions, broad-based and large UIA endovascular treatment with the WEB and adjunctive techniques was feasible with a low risk of complications and promising occlusion rates in mid-term follow-up.

  10. Endovascular treatment of sphenoid wing dural arteriovenous fistula with pure cortical venous drainage.

    PubMed

    Fukuda, Hitoshi; Miyake, Kosuke; Kunieda, Takenobu; Murao, Kenichi

    2014-07-01

    Curative endovascular treatment of sphenoid wing dural arteriovenous fistula (dAVF) with pure cortical venous drainage is challenging because of its rarity, lack of accessible dural sinus for transvenous embolization (TVE), and proximity of skull base vital regions. Direct surgery to disconnect venous reflux has been favored. We report the curative endovascular treatment of two sphenoid wing dAVFs with pure cortical venous drainage. One patient revealed complete obliteration of dAVF by a single session of transarterial embolization (TAE). As part of strategic TAE for this complex dAVF, we used a novel approach to create a complete flow-arrest condition in which coils and an occlusion balloon were combined. A liquid agent was then injected across the pathological fistula and into the parent venous apparatus, thereby occluding the lesion. The other patient was treated with percutaneous TVE after TAE was unsuccessful. With a specific strategy and appropriate devices, the microcatheter was successfully introduced through sigmoid sinus, transverse sinus, superior sagittal sinus, and refluxing cortical vein by puncture of the jugular vein. Coils were deployed at the venous side of the fistula, resulting in successful obliteration of the dAVF. Sphenoid wing dAVF with pure cortical venous drainage could be curable by endovascular treatment with proper strategy and instruments when anatomical condition permits.

  11. The imaging assessment and specific endograft design for the endovascular repair of ascending aortic dissection

    PubMed Central

    Zhang, Yepeng; Tang, Hanfei; Zhou, JianPing; Liu, Zhao; Liu, Changjian; Qiao, Tong; Zhou, Min

    2016-01-01

    Background Endovascular option has been proposed for a very limited and selected number of Stanford type A aortic dissection (TAAD) patients. We have performed a computed tomography (CT)-based TAAD study to explore appropriate endograft configurations for the ascending aortic pathology. Methods TAAD patients treated with optimal CT scans were retrospectively reviewed, and their entry tears (ETs) were identified using three-dimensional and multiplanar reconstructions in an EndoSize workstation. After generating a centerline of flow, measurements, including numerous morphologic characteristics of anatomy, were evaluated and a selected subset of patients were determined to be suitable for endovascular treatments. Proximal diameter and distal diameter of endograft were selected based on diameters measured at the ET level and at the innominate artery (IA) level, with 10% oversizing with respect to the true lumen, but not exceeding the original aortic diameter. The length of the endograft was determined by the distance from the sinotubular junction to IA. Results This study covered 126 TAAD patients with primary ET in ascending aorta, among which, according to the assumed criteria, 48 (38.1%) patients were deemed to be suitable for endovascular treatment. The diameters of ascending aorta from the sinotubular junction to the IA level presented a downward trend, and the proximal diameters differed significantly from distal diameters of the endograft for TAAD (39.9 versus 36.2 mm, P<0.01), implying that the conical endograft might be compatible with the ascending pathology. In the ascending aorta, lengths of the endograft should be 50, 60, 70, 80, and 90 mm in five (10.4%), 22 (45.9%), 13 (27.1%), six (12.5%), and two (4.2%) patients, respectively. Conclusion In this selected number of Chinese patients, the suitability of endovascular repair has been demonstrated based on the CT imaging. Shorter, larger, and bare spring-free conical endografts were preferred in the

  12. The Use of Branched Endografts for the Aortic Arch in the Endovascular Era.

    PubMed

    Tadros, Rami O; Safir, Scott R; Faries, Peter L; Han, Daniel K; Chander, Rajiv K; Abraham, Cherrie Z; Marin, Michael L; Stewart, Allan S

    2017-07-25

    The endovascular realm has steadily increased its footing in the treatment of the aorta and all of its territories since the foundational case in 1990 by Parodi. The aortic arch, however, continues to be one of the last bastions for treatment via open surgery, which remains the gold standard. Significant comorbidity and prior cardiac surgery prevent open surgery from being the only preferred option, allowing novel endovascular procedures to be considered. Since 1999, more advanced endovascular systems have been created by companies such as Cook Medical, Bolton Medical, Medtronic, Endospan, Gore Medical, and, recently, Kawasumi. The unique shape and angulation of the aortic arch often require the use of custom-made grafts, though arch reconstruction may also include in situ or back-table physician alterations to off-the-shelf devices. The goal of branched endografts is to exclude the aneurysm, while maintaining flow to supra-aortic trunk vessels. Technical success and device durability are limited by the physical constraints of the aortic arch, though greater experience may yield better patient outcomes. Typically, the initial stent-graft (SG) is introduced and deployed into the arch first. Bridging SG are then inserted via axillary or carotid access. Most often, the bridging SG extends from the innominate branch to the distal innominate, and from the left carotid branch to the left common carotid. The major concern is that manipulation of catheters and wires, both within the carotid arteries and aortic arch, create the potential for emboli leading to stroke and paraplegia. The development of endovascular-only techniques for aortic arch pathology will only increase with the aging population of the United States and associated accumulation of comorbidities, making open surgery too grave of a risk.

  13. Endovascular Laser Therapy for Varicose Veins

    PubMed Central

    2010-01-01

    back pain and arthritis. Lower limb VV is a common disease affecting adults and estimated to be the seventh most common reason for physician referral in the US. There is a strong familial predisposition to VV with the risk in offspring being 90% if both parents affected, 20% when neither is affected, and 45% (25% boys, 62% girls) if one parent is affected. Globally, the prevalence of VV ranges from 5% to 15% among men and 3% to 29% among women varying by the age, gender and ethnicity of the study population, survey methods and disease definition and measurement. The annual incidence of VV estimated from the Framingham Study was reported to be 2.6% among women and 1.9% among men and did not vary within the age range (40-89 years) studied. Approximately 1% of the adult population has a stasis ulcer of venous origin at any one time with 4% at risk. The majority of leg ulcer patients are elderly with simple superficial vein reflux. Stasis ulcers are often lengthy medical problems and can last for several years and, despite effective compression therapy and multilayer bandaging are associated with high recurrence rates. Recent trials involving surgical treatment of superficial vein reflux have resulted in healing and significantly reduced recurrence rates. Endovascular Laser Therapy for VV ELT is an image-guided, minimally invasive treatment alternative to surgical stripping of superficial venous reflux. It does not require an operating room or general anesthesia and has been performed in outpatient settings by a variety of medical specialties including surgeons (vascular or general), interventional radiologists and phlebologists. Rather than surgically removing the vein, ELT works by destroying, cauterizing or ablating the refluxing vein segment using heat energy delivered via laser fibre. Prior to ELT, colour-flow Doppler ultrasonography is used to confirm and map all areas of venous reflux to devise a safe and effective treatment plan. The ELT procedure involves the

  14. The model for Fundamentals of Endovascular Surgery (FEVS) successfully defines the competent endovascular surgeon.

    PubMed

    Duran, Cassidy; Estrada, Sean; O'Malley, Marcia; Sheahan, Malachi G; Shames, Murray L; Lee, Jason T; Bismuth, Jean

    2015-12-01

    Fundamental skills testing is now required for certification in general surgery. No model for assessing fundamental endovascular skills exists. Our objective was to develop a model that tests the fundamental endovascular skills and differentiates competent from noncompetent performance. The Fundamentals of Endovascular Surgery model was developed in silicon and virtual-reality versions. Twenty individuals (with a range of experience) performed four tasks on each model in three separate sessions. Tasks on the silicon model were performed under fluoroscopic guidance, and electromagnetic tracking captured motion metrics for catheter tip position. Image processing captured tool tip position and motion on the virtual model. Performance was evaluated using a global rating scale, blinded video assessment of error metrics, and catheter tip movement and position. Motion analysis was based on derivations of speed and position that define proficiency of movement (spectral arc length, duration of submovement, and number of submovements). Performance was significantly different between competent and noncompetent interventionalists for the three performance measures of motion metrics, error metrics, and global rating scale. The mean error metric score was 6.83 for noncompetent individuals and 2.51 for the competent group (P < .0001). Median global rating scores were 2.25 for the noncompetent group and 4.75 for the competent users (P < .0001). The Fundamentals of Endovascular Surgery model successfully differentiates competent and noncompetent performance of fundamental endovascular skills based on a series of objective performance measures. This model could serve as a platform for skills testing for all trainees. Copyright © 2015 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

  15. Separation of silver nanoparticles by hollow fiber flow field-flow fractionation: Addition of tannic acid into carrier liquid as a modifier.

    PubMed

    Saenmuangchin, Rattaporn; Mettakoonpitak, Jaruwan; Shiowatana, Juwadee; Siripinyanond, Atitaya

    2015-10-09

    A homemade hollow fiber flow-field fractionation (Hf-FlFFF) coupled with inductively coupled plasma mass spectrometry (ICP-MS) was set-up for silver nanoparticles (AgNPs) separation by using polysulfone hollow fiber membrane (30,000 MW cutoff) as a separation channel. Tannic acid and citrate stabilized AgNPs were synthesized and introduced into Hf-FlFFF. The effects of carrier liquid and stabilizing agent on retention behavior of AgNPs were investigated. Different elution behaviors were observed as follows: with 0.02% (w/v) FL-70, all of AgNPs were eluted from Hf-FlFFF but differences in retention behaviors were observed for AgNPs with tannic acid and citrate stabilizing agents; and with 30mM TRIS buffer, only tannic acid stabilized AgNPs were eluted from Hf-FlFFF, whereas citrate stabilized AgNPs were not eluted. In this work, tannic acid addition into carrier liquid was proposed to modify the surface of AgNPs and the surface of the membrane, and thereby adjusting the retention behaviors of AgNPs. Various concentrations of tannic acid were added into FL-70 and TRIS buffer. With the use of 0.1mM tannic acid in 30mM TRIS buffer as the carrier liquid, retention behaviors of both tannic acid stabilized- and citrate stabilized-AgNPs were similar and with similar fractionation recovery.

  16. Optimization of an endovascular magnetic filter for maximized capture of magnetic nanoparticles.

    PubMed

    Kondapavulur, Sravani; Cote, Andre M; Neumann, Kiel D; Jordan, Caroline D; McCoy, David; Mabray, Marc C; Liu, Derek; Sze, Chia-Hung; Gautam, Ayushi; VanBrocklin, Henry F; Wilson, Mark; Hetts, Steven W

    2016-12-01

    To computationally optimize the design of an endovascular magnetic filtration device that binds iron oxide nanoparticles and to validate simulations with experimental results of prototype devices in physiologic flow testing. Three-dimensional computational models of different endovascular magnetic filter devices assessed magnetic particle capture. We simulated a series of cylindrical neodymium N52 magnets and capture of 1500 iron oxide nanoparticles infused in a simulated 14 mm-diameter vessel. Device parameters varied included: magnetization orientation (across the diameter, "D", along the length, "L", of the filter), magnet outer diameter (3, 4, 5 mm), magnet length (5, 10 mm), and spacing between magnets (1, 3 mm). Top designs were tested in vitro using (89)Zr-radiolabeled iron oxide nanoparticles and gamma counting both in continuous and multiple pass flow model. Computationally, "D" magnetized devices had greater capture than "L" magnetized devices. Increasing outer diameter of magnets increased particle capture as follows: "D" designs, 3 mm: 12.8-13.6 %, 4 mm: 16.6-17.6 %, 5 mm: 21.8-24.6 %; "L" designs, 3 mm: 5.6-10 %, 4 mm: 9.4-15.8 %, 5 mm: 14.8-21.2 %. In vitro, while there was significant capture by all device designs, with most capturing 87-93 % within the first two minutes, compared to control non-magnetic devices, there was no significant difference in particle capture with the parameters varied. The computational study predicts that endovascular magnetic filters demonstrate maximum particle capture with "D" magnetization. In vitro flow testing demonstrated no difference in capture with varied parameters. Clinically, "D" magnetized devices would be most practical, sized as large as possible without causing intravascular flow obstruction.

  17. Ultrasensitive flow injection chemiluminescence detection of DNA hybridization using signal DNA probe modified with Au and CuS nanoparticles.

    PubMed

    Zhang, Shusheng; Zhong, Hua; Ding, Caifeng

    2008-10-01

    A novel and sensitive flow injection chemiluminescence assay for sequence-specific DNA detection based on signal amplification with nanoparticles (NPs) is reported in the present work. The "sandwich-type" DNA biosensor was fabricated with the thiol-functionalized capture DNA first immobilized on an Au electrode and hybridized with one end of target DNA, the other end of which was recognized with a signal DNA probe labeled with CuS NPs and Au NPs on the 3'- and 5'-terminus, respectively. The hybridization events were monitored by the CL intensity of luminol-H2O2-Cu(2+) after the cupric ions were dissolved from the hybrids. We demonstrated that the incorporation of Au NPs in this sensor design significantly enhanced the sensitivity and the selectivity because a single Au NP can be loaded with hundreds of signal DNA probe strands, which were modified with CuS NPs. The ratios of Au NPs, signal DNA probes, and CuS NPs modified on the gold electrode were approximately 1/101/103. A preconcentration process of cupric ions performed by anodic stripping voltammetry technology further increased the sensor performance. As a result of these two combined effects, this DNA sensor could detect as low as femtomolar target DNA and exhibited excellent selectivity against two-base mismatched DNA. Under the optimum conditions, the CL intensity was increased with the increase of the concentration of target DNA in the range of 2.0 x 10(-14)-2.0 x 10(-12) M. A detection limit of 4.8 x 10(-15) M target DNA was achieved.

  18. Endovascular treatment of the carotid stump syndrome.

    PubMed

    Nano, Giovanni; Dalainas, Ilias; Casana, Renato; Malacrida, Giovanni; Tealdi, Domenico G

    2006-01-01

    In patients with an occluded internal carotid artery, the carotid stump syndrome is a potential source of microemboli that pass through the ipsilateral external carotid artery and the ophthalmic artery to the territory of the middle cerebral artery. Thus, the syndrome is associated with carotid territory symptoms although the internal carotid artery is occluded. Surgical exclusion of the internal carotid artery associated with endarterectomy of the external carotid artery has been described as the gold standard of treatment by many authors. This report is the second case, to our knowledge, of endovascular treatment of the carotid stump syndrome with the use of a stent-graft.

  19. Endovascular revascularization for aortoiliac atherosclerotic disease

    PubMed Central

    Aggarwal, Vikas; Waldo, Stephen W; Armstrong, Ehrin J

    2016-01-01

    Atherosclerotic iliac artery disease is increasingly being treated with endovascular techniques. A number of new stent technologies can be utilized with high long-term patency, including self-expanding stents, balloon-expandable stents, and covered stents, but comparative data on these stent types and in more complex lesions are lacking. This article provides a review of currently available iliac stent technologies, as well as complex procedural aspects of iliac artery interventions, including approaches to the treatment of iliac bifurcation disease, long segment occlusions, choice of stent type, and treatment of iliac artery in-stent restenosis. PMID:27099509

  20. Endovascular Techniques in Limb Salvage: Stents

    PubMed Central

    El-Sayed, Hosam F.

    2013-01-01

    In patients with critical limb ischemia, the first-line approach for limb salvage has shifted over the past decade from bypass surgery to endovascular intervention. Stenting for the treatment of lower-extremity arterial occlusive disease is an important tool and continues to evolve, with new stent designs and technologies that have been developed to provide superior patency rates and limb salvage. In this article, we discuss the role of peripheral stenting in the treatment of patients with critical limb ischemia, including a review of the relevant current literature and the future directions of such interventions. PMID:23805339

  1. Radial artery access for peripheral endovascular procedures.

    PubMed

    Kumar, Avnee J; Jones, Lauren E; Kollmeyer, Kenneth R; Feldtman, Robert W; Ferrara, Craig A; Moe, Michelle N; Chen, Julia F; Richmond, Jasmine L; Ahn, Sam S

    2017-09-01

    The radial artery is often used for coronary angiography, with a demonstrated decrease in local complications and an increase in postoperative mobility of the patient. Data on radial artery access for peripheral endovascular procedures, however, are limited. We describe our experience with radial artery access for diagnostic and endovascular interventions. Between February 2012 and March 2015, there were 95 endovascular procedures performed using radial artery access in 80 unique patients. Demographic and clinical data were recorded. Perioperative, postoperative, and 30-day follow-up data were evaluated retrospectively for major and minor complications. Major adverse events included any immediate hospitalization admission, stroke, hand amputation, bleeding requiring transfusion, hematoma requiring surgery, and death. Minor complications included superficial bleeding and hematoma. The patients (52.6% male, 47.4% female) had a mean age of 72.1 ± 9.4 years. Radial artery access was used for diagnostic purposes in 15.8% of all procedures and for therapeutic intervention, including angioplasty and stenting, in 84.2%. The radial artery was the only access point in 80% of patients and was accessed in conjunction with other sites in 20%. Percutaneous access was achieved in 100% of patients with a 100% technical success rate. Hemostasis after catheterization was achieved by manual compression (22.1%) and TR band (Terumo Medical, Tokyo, Japan; 77.9%). Major adverse events occurred in three cases (3.2%) and were unrelated to radial artery access. Radial artery access site-related complications occurred in three cases (3.2%), all of which were minor hematomas that required no treatment. The risk of radial artery complication was not associated with procedure type, vessels treated, or use of heparin. The incidence of stroke, hand ischemia, and upper extremity limb or finger loss was 0%. Radial artery access for peripheral endovascular procedures appears to be safe and

  2. Anesthetic strategy during endovascular therapy: General anesthesia or conscious sedation? (GOLIATH - General or Local Anesthesia in Intra Arterial Therapy) A single-center randomized trial.

    PubMed

    Simonsen, Claus Z; Sørensen, Leif H; Juul, Niels; Johnsen, Søren P; Yoo, Albert J; Andersen, Grethe; Rasmussen, Mads

    2016-12-01

    Endovascular therapy after acute ischemic stroke due to large vessel occlusion is now standard of care. There is equipoise as to what kind of anesthesia patients should receive during the procedure. Observational studies suggest that general anesthesia is associated with worse outcomes compared to conscious sedation. However, the findings may have been biased. Randomized clinical trials are needed to determine whether the choice of anesthesia may influence outcome. The objective of GOLIATH (General or Local Anestesia in Intra Arterial Therapy) is to examine whether the choice of anesthetic regime during endovascular therapy for acute ischemic stroke influence patient outcome. Our hypothesis is that that conscious sedation is associated with less infarct growth and better functional outcome. GOLIATH is an investigator-initiated, single-center, randomized study. Patients with acute ischemic stroke, scheduled for endovascular therapy, are randomized to receive either general anesthesia or conscious sedation. The primary outcome measure is infarct growth after 48-72 h (determined by serial diffusion-weighted magnetic resonance imaging). Secondary outcomes include 90-day modified Rankin Scale score, time parameters, blood pressure variables, use of vasopressors, procedural and anesthetic complications, success of revascularization, radiation dose, and amount of contrast media. Choice of anesthesia may influence outcome in acute ischemic stroke patients undergoing endovascular therapy. The results from this study may guide future decisions regarding the optimal anesthetic regime for endovascular therapy. In addition, this study may provide preliminary data for a multicenter randomized trial. © 2016 World Stroke Organization.

  3. Beyond the use of modifiers in selective alkyne hydrogenation: silver and gold nanocatalysts in flow mode for sustainable alkene production

    NASA Astrophysics Data System (ADS)

    Vilé, Gianvito; Pérez-Ramírez, Javier

    2014-10-01

    We report on the excellent stereo and chemoselectivity of nanosized silver and gold catalysts in the three-phase hydrogenation of acetylenic compounds under flow chemistry conditions. The materials featuring metal nanoparticles in the range of 2-21 nm were prepared by spray deposition or incipient wetness impregnation of silver nitrate and sol immobilisation of gold chloride on different carriers (Al2O3, SiO2, TiO2, and carbon), followed by activation in various atmospheres. The samples were characterised by ICP-OES, N2 sorption, XPS, HAADF-STEM, and HRTEM, and evaluated in a continuous-flow flooded-bed micro-reactor. Both metals display optimal activities for particles below 5 nm, enabling stable operation at T = 373 K and P = 10 bar. While the performance of the silver catalysts is less influenced by the support, the gold nanoparticles exhibit significant activity only when deposited on TiO2, likely due to the strong metal-support interaction. Hydrogenations of functionalised alkynes reveal that silver and gold match, and in some cases exceed, the selectivity of benchmark palladium-based catalysts. Furthermore, in contrast to Pd, the Ag and Au samples require no modifiers, which brings fundamental and practical simplifications for their understanding and large scale manufacture. Therefore, these materials could be advantageously used for the continuous production of olefinic intermediates in the fine chemical and pharmaceutical industries.We report on the excellent stereo and chemoselectivity of nanosized silver and gold catalysts in the three-phase hydrogenation of acetylenic compounds under flow chemistry conditions. The materials featuring metal nanoparticles in the range of 2-21 nm were prepared by spray deposition or incipient wetness impregnation of silver nitrate and sol immobilisation of gold chloride on different carriers (Al2O3, SiO2, TiO2, and carbon), followed by activation in various atmospheres. The samples were characterised by ICP-OES, N2 sorption

  4. The Addition of Endovascular Intervention for Dural Venous Sinus Thrombosis: Single-Center Experience and Review of Literature.

    PubMed

    Nyberg, Eric M; Case, David; Nagae, Lidia M; Honce, Justin M; Reyenga, William; Seinfeld, Joshua; Poisson, Sharon; Leppert, Michelle H

    2017-10-01

    Dural venous sinus thrombosis (DVST) is a cause of infarction and intracranial hemorrhage (ICH) that can lead to significant morbidity. Endovascular therapy has emerged as an adjunctive therapy in select cases but has been associated with increased hemorrhagic complications. We present our experience with a large single-center cohort of DVST cases treated with current-generation thrombectomy devices. In this retrospective cohort study, a chart review was performed to compare presentations and outcomes of patients treated with anticoagulation alone with those treated with additional interventional therapy, using the modified Rankin Scale (mRS) score at discharge and at 90 days' follow-up. A total of 66 patients were included; 37 were treated with anticoagulation alone, and 29 underwent additional interventional therapy. Patients presenting with ICH or infarction had a significantly greater likelihood of disability at the time of discharge (odds ratio [OR] of 64.5 and 45.8, respectively; P < .0001) and at 90 days (OR of 28.4 and 22.8, respectively; P < .0001). Patients presenting with ICH or infarction were more likely to be selected for endovascular therapy (P < .05). Endovascular therapy was typically performed within 24 hours of admission; 9 patients (31%) had post-treatment hemorrhage, with 2 being (6.9%) symptomatic. There were fewer patients with slight disability (mRS score ≤1) in the endovascular group compared with the anticoagulation group at discharge (P = .05), but outcomes were not significantly different at 90 days (P = .19). Despite a higher rate of ICH or infarction at presentation in the endovascular group and an increased risk of postprocedural ICH, both treatment groups had similarly good functional outcomes at 90 days. Copyright © 2017 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  5. Endovascular Treatment of Symptomatic Vertebral Artery Dissecting Aneurysms

    PubMed Central

    Han, Jinsol; Ha, Sung-Kon; Choi, Jong-Il; Jin, Sung-Won; Kim, Se-Hoon

    2016-01-01

    Objective Vertebral artery dissecting aneurysms (VADAs) are rare and many debates are present about treatment options. We review types and efficacy of our endovascular treatments and establish a safe endovascular therapeutic strategy regard to the angio-architecture of VADAs. Materials and Methods Between July 2008 and October 2015, we treated 22 patients with symptomatic VADAs. Fifteen patients presented with subarachnoid hemorrhage from the ruptured VADAs, digital subtraction angiography and magnetic resonance image confirmed the diagnosis and endovascular treatments were followed as their angio-architecture. Results Clinical results were good in 13 patients (86.7%), and there were no technical problems during endovascular procedures. The other 2 patients with poor prognosis showed severe neurological deficits at the initial evaluation. Among the three different endovascular treatments, there were no radiologic cure in one patient with stent insertion alone, but the patient had no significant clinical symptoms either. Conclusion Endovascular treatments are safe and effective treatment option for managing VADAs and can be the first treatment of choice for most patients. To select proper endovascular treatment according to the angio-architecture of VADAs can reduce the risk of the treatment. PMID:27847762

  6. A Coupled Thermal/Material Flow Model of Friction Stir Welding Applied to Sc-Modified Aluminum Alloys

    NASA Astrophysics Data System (ADS)

    Hamilton, Carter; Kopyściański, Mateusz; Senkov, Oleg; Dymek, Stanislaw

    2013-04-01

    A coupled thermal/material flow model of friction stir welding was developed and applied to the joining of Sc-modified aluminum alloy (7042-T6) extrusions. The model reveals that surface material is pulled from the retreating side into the weld zone where it is interleaved with in situ material. Due to frictional contact with the shoulder, the surface material is hotter than the in situ material, so that the final weld microstructure is composed of bands of material with different temperature histories. For this alloy and the associated FSW heating rates, secondary phase dissolution/precipitation temperatures are in proximity to the welding temperatures. Therefore, depending on the surface and in situ material temperatures in relation to these transformation temperatures, disparate precipitate distributions can develop in the bands of material comprising the weld nugget. Based on the numerical simulation and on thermal analysis data from differential scanning calorimetry, a mechanism for the formation of onion rings within the weld zone is presented.

  7. Subjective Cognitive Decline Modifies the Relationship Between Cerebral Blood Flow and Memory Function in Cognitively Normal Older Adults.

    PubMed

    Hays, Chelsea C; Zlatar, Zvinka Z; Campbell, Laura; Meloy, M J; Wierenga, Christina E

    2017-10-04

    Subjective cognitive decline (SCD), or self-reported cognitive decline despite normal neuropsychological test performance, is a risk factor for objective cognitive decline and Alzheimer's disease (AD). While brain mechanisms contributing to SCD are not well defined, studies show associations with vascular risk factors and altered cerebral blood flow (CBF), raising the hypothesis that those with SCD might be experiencing vascular dysregulation, or a disruption in the normal relationship between CBF and cognition. We examined whether the association between CBF and verbal memory performance differs between those with SCD (SCD+) and those without SCD (SCD-). Linear mixed-effects models were used to investigate whether the voxel-wise relationship between arterial spin labeling (ASL) MRI-measured CBF and verbal memory performance was modified by SCD among a group of 70 cognitively normal older adults (35 SCD+, 35 SCD-; mean age=72) matched on age, gender, and symptoms of depression. Results indicated that the SCD- group exhibited positive associations between verbal memory and CBF within the posterior cingulate cortex, middle temporal gyrus, and inferior frontal gyrus, whereas the SCD+ group displayed negative associations between verbal memory and CBF within the posterior cingulate cortex, middle temporal gyrus, hippocampus, fusiform gyrus, and inferior frontal gyrus. Findings suggest that, while higher CBF is supportive of memory function in those without SCD, higher CBF may no longer support memory function in those presenting with SCD, perhaps reflecting neurovascular dysregulation. (JINS, 2017, 23, 1-11).

  8. On a modified Monte-Carlo method and variable soft sphere model for rarefied binary gas mixture flow simulation

    NASA Astrophysics Data System (ADS)

    Nourazar, S. S.; Jahangiri, P.; Aboutalebi, A.; Ganjaei, A. A.; Nourazar, M.; Khadem, J.

    2011-06-01

    The effect of new terms in the improved algorithm, the modified direct simulation Monte-Carlo (MDSMC) method, is investigated by simulating a rarefied binary gas mixture flow inside a rotating cylinder. Dalton law for the partial pressures contributed by each species of the binary gas mixture is incorporated into our simulation using the MDSMC method and the direct simulation Monte-Carlo (DSMC) method. Moreover, the effect of the exponent of the cosine of deflection angle (α) in the inter-molecular collision models, the variable soft sphere (VSS) and the variable hard sphere (VHS), is investigated in our simulation. The improvement of the results of simulation is pronounced using the MDSMC method when compared with the results of the DSMC method. The results of simulation using the VSS model show some improvements on the result of simulation for the mixture temperature at radial distances close to the cylinder wall where the temperature reaches the maximum value when compared with the results using the VHS model.

  9. Comparison and evaluation of seven different bench-top flow cytometers with a modified six-plexed mycotoxin kit.

    PubMed

    Czeh, Arpad; Schwartz, Abe; Mandy, Frank; Szoke, Zsuzsanna; Koszegi, Balazs; Feher-Toth, Szilvia; Nagyeri, Gyorgy; Jakso, Pal; Katona, Robert L; Kemeny, Agnes; Woth, Gabor; Lustyik, Gyorgy

    2013-12-01

    Many bench-top flow cytometers (b-FCs) are compatible with microsphere-based multiplexed assays. Disciplines implementing b-FCs-based assays are expanding; they include monitoring and validating food quality. A multiplexed platform protocol was evaluated for poly-mycotoxin assays, which is compatible with a variety of b-FC models. The seven instruments included: BD FACSCalibur(™) , BD FACSArray(™) Bioanalyzer, Accuri C6, Partec CyFlow(®) Space, Beckman Coulter FC 500, Guava EasyCyte Mini, and Luminex 100 (™) . Current reports related to the food industry describe fungal co-infections leading to poly-mycotoxin contamination in grain (Sulyok M, Berthiller F, Krska R, Schuhmacher R, Rapid Commun Mass Spectrom 2006;20:2649-2659). It is imperative to determine whether b-FC-based assays can replace traditional single-mycotoxin enzyme-linked immunosorbent assay (ELISA). A six-plexed poly-mycotoxin kit was tested on seven different b-FCs. The modified kit was initially developed for the BD FACSArray(™) Bioanalyzer (BD Biosciences) (Czeh A, Mandy F, Feher-Toth S, Torok L, Mike Z, Koszegi B, Lustyik G, J Immunol Methods 2012;384:71-80). With the multiplexed platform, it is possible to identify up to six mycotoxin contaminants simultaneously at regional grain collection/transfer/inspection facilities. In the future, elimination of contaminated food threat may be better achieved with the inclusion of b-FCs in the food protection arsenal. A universal protocol, matched with postacquisition software, offers an effective alternative platform compared to using a series of ELISA kits. To support side-by-side evaluation of seven flow cytometers, an instrument-independent fluorescence emission calibration was added to the protocol. All instrument performances were evaluated for strength of agreement based on paired sets of evaluation to predicate method. The results suggest that all b-FCs were acceptable of performing with the multiplexed kit for five of six mycotoxins. For

  10. Application of a Novel Brain Arteriovenous Malformation Endovascular Grading Scale for Transarterial Embolization.

    PubMed

    Bell, D L; Leslie-Mazwi, T M; Yoo, A J; Rabinov, J D; Butler, W E; Bell, J E; Hirsch, J A

    2015-07-01

    The advent of modern neuroendovascular techniques has highlighted the need for a simple, effective, and reliable brain arteriovenous malformation endovascular grading scale. A novel scale of this type has recently been described. It incorporates the number of feeding arteries, eloquence, and the presence of an arteriovenous fistula component. Our aim is to assess the validity of this grading scale. We retrospectively reviewed all suspected brain arteriovenous malformations at Massachusetts General Hospital from 2005 to 2013, identifying 126 patients who met the inclusion criteria. Spearman correlations between endovascular and Spetzler-Martin grading scales and long-term outcomes were performed. Median endovascular grades were compared between treatment modalities and endovascular outcomes. Binary regression analysis was performed with major endovascular complications as a dichotomized dependent variable. Intraclass correlation coefficients were calculated for interobserver reliability of the endovascular grading scale. A significant Spearman correlation between the endovascular grade and the Spetzler-Martin grade was demonstrated (ρ = 0.5, P < .01). Differences in the median endovascular grades between the endovascular cure (median = 2) and endovascular complication groups (median = 4) (P < .05) and between the endovascular cure and successful multimodal treatment groups (median = 3) (P < .05) were demonstrated. The endovascular grade was the only independent predictor of complications (OR = 0.5, P < .01). The intraclass correlation coefficient of the endovascular grade was 0.71 (P < .01). Validation of a brain arteriovenous malformation endovascular grading scale demonstrated that endovascular grades of ≤II were associated with endovascular cure, while endovascular grades of ≤III were associated with multimodal cure or significant lesion reduction and favorable outcome. The endovascular grade provides useful information to refine risk stratification for

  11. Endovascular treatment of abdominal aortic aneurysms

    PubMed Central

    Buck, Dominique B.; van Herwaarden, Joost A.; Schermerhorn, Marc L.; Moll, Frans L.

    2014-01-01

    Patients with abdominal aortic aneurysms (AAAs) are usually treated with endovascular aneurysm repair (EVAR), which has become the standard of care in many hospitals for patients with suitable anatomy. Clinical evidence indicates that EVAR is associated with superior perioperative outcomes and similar long-term survival compared with open repair. Since the randomized, controlled trials that provided this evidence were conducted, however, the stent graft technology for infrarenal AAA has been further developed. Improvements include profile downsizing, optimization of sealing and fixation, and the use of low porosity fabrics. In addition, imaging techniques have improved, enabling better preoperative planning, stent graft placement, and postoperative surveillance. Also in the past few years, fenestrated and branched stent grafts have increasingly been used to manage anatomically challenging aneurysms, and experiments with off-label use of stent grafts have been performed to treat patients deemed unfit or unsuitable for other treatment strategies. Overall, the indications for endovascular management of AAA are expanding to include increasingly complex and anatomically challenging aneurysms. Ongoing studies and optimization of imaging, in addition to technological refinement of stent grafts, will hopefully continue to broaden the utilization of EVAR. PMID:24343568

  12. Endovascular Exclusion of Mycotic Aortic Aneurysm

    PubMed Central

    Takach, Thomas J.; Kane, Peter N.; Madjarov, Jeko M.; Holleman, Jeremiah H.; Robicsek, Francis; Roush, Timothy S.

    2007-01-01

    The presence of prohibitive risk may preclude usual surgical management. Such was the case for a critically ill, 60-year-old woman who presented with concomitant, life-threatening conditions. The patient presented with acute central cord syndrome and lower-extremity paraplegia after completing a 6-week course of intravenous antibiotics for methicillin-sensitive Staphylococcus aureus bacteremia and osteomyelitis of the thoracic spine. Radiologic examination revealed bony destruction of thoracic vertebrae T4 through T6, impingement on the spinal cord and canal by an inflammatory mass, and a separate 2.5-cm mycotic aneurysm of the infrarenal aorta. The clinical and radiologic findings warranted immediate decompression and stabilization of the spinal cord, aneurysmectomy, and vascular reconstruction. However, the severely debilitated patient could not tolerate 2 simultaneous open procedures. She underwent emergent endovascular exclusion of the mycotic aneurysm with a stent-graft, followed immediately by laminectomy and stabilization of the thoracic spine. Intraoperative microbiology specimens showed no growth. The patient was maintained on prophylactic antibiotic therapy for 6 months. Fourteen months postoperatively, her neurologic function was near full recovery, and neither surveillance blood cultures nor radiologic examinations showed a recurrence of infection or aneurysm. Although the long-term outcome of endovascular stent-grafts in the treatment of culture-negative mycotic aneurysms is unknown, the use of these grafts in severely debilitated patients can reduce operative risk and enable recovery in the short term. PMID:18172531

  13. [Endovascular treatment of descending thoracic aorta aneurysm].

    PubMed

    Mertens, Renato; Valdés, Francisco; Krämer, Albrecht; Mariné, Leopoldo; Irarrázaval, Manuel; Morán, Sergio; Zalaquet, Ricardo; Schwartz, Eitan; Vergara, Jeannette; Valdebenito, Magaly

    2003-06-01

    The natural history of aneurysms ends in rupture and death. In 1990 the first endovascular exclusion of an aneurysm, using an endoluminal graft implanted through the femoral arteries was performed. More recently, the same procedure has been used for aneurysms of the thoracic aorta. To report our experience with endovascular treatment of thoracic aorta aneurysms. Analysis of 14 patients (nine male), aged 30 to 79 years, treated between May 2001 and August 2002. The mean diameter of the aneurysms was 6.9 cm. The etiology was atherosclerotic in nine patients. The Excluder device (Gore) was preferentially used. There was no operative mortality or paraplegia. One patient had a transient leg monoparesis that reverted completely. No patient had type I endoleaks. Two patients had type II endoleaks on discharge, that sealed spontaneously. In a follow up, ranging from 2 to 17 months, one patient died of a bronchopneumonia and no aneurysm rupture has been detected. The short term results of endoluminal treatment of thoracic aorta aneurysms are excellent. This treatment is less invasive and has less complications than conventional surgery.

  14. Endovascular treatment of primary hepatic tumours

    PubMed Central

    Popiel, M; Gulie, L; Turculeţ, C; Beuran, M

    2008-01-01

    First transcatheter embolization of hepatic artery has been materializing in 1974, in France, for unresectable hepatic tumours. Then, this treatment has become use enough in many countries, especially in Japan, where primary hepatic tumours are very frequent. In this article, we present procedures of interventional endovascular treatment for primary hepatic tumours: chemoembolization, intra–arterial chemotherapy. The study comprises patients with primary hepatic tumours investigated by hepatic–ultrasound and contrast–enhanced CT or MRI. DSA–hepatic angiography is very important to verify the accessory hepatic supply. It has been performed selective catheterization of right/left hepatic branches followed by cytostatics injection. Most of the patients have benefit by hepatic chemoembolization (cytostatics, Lipiodol and embolic materials). The selective intra–arterial chemotherapy (cytostatics without Lipiodol) was performing in cases with contraindications for Lipiodol or embolic materials injection (cirrhosis–Child C, thrombosis of portal vein, hepatic insufficiency). For treatment of primary hepatic tumours we use 5–F–Uracil, Farmarubicin and Mytomicin C. Less numbers of the reservoirs were placed because financial causes. Chemoembolization was better than procedures without Lipiodol or embolic materials. Lipiodol reached in tumoural tissue and the distribution of Lipiodol harmonises with degree of vascularisation. After the chemoembolization procedure, the diameter of tumours decreased gradually depending on the size of tumour. Effective alternative for unresectable primary hepatic tumours (big size, hepatic dysfunction, and other surgical risk factors) is endovascular interventional treatment. PMID:20108517

  15. The Endovascular Management of Iliac Artery Aneurysms

    SciTech Connect

    Stroumpouli, Evangelia; Nassef, Ahmed; Loosemore, Tom; Thompson, Matt; Morgan, Robert; Belli, Anna-Maria

    2007-11-15

    Background: Isolated aneurysms of the iliac arteries are uncommon. Previously treated by conventional surgery, there is increasing use of endografts to treat these lesions. Purpose: The purpose of this study was to assess the efficacy, safety, and durability of the stent-grafts for treatment of iliac artery aneurysms (IAAs). The results of endografting for isolated IAAs over a 10-year period were analyzed retrospectively. The treatment methods differed depending on the anatomic location of the aneurysms. Twenty-one patients (1 woman, 20 men) underwent endovascular stent-graft repair, with one procedure carried out under emergency conditions after acute rupture. The mean aneurysm diameter was 4.6 cm.Results:The procedural technical success was 100%. There was zero 30-day mortality. Follow-up was by interval CT scans. At a mean follow-up of 51.2 months, the stent-graft patency rate was 100%. Reintervention was performed in four patients (19%): one patient (4.7%) with a type I endoleak and three patients (14.3%) with type II endoleaks.Conclusion:We conclude that endovascular repair of isolated IAAs is a safe, minimally invasive technique with low morbidity rates. Follow-up results up to 10 years suggest that this approach is durable and should be regarded as a first treatment option for appropriate candidates.

  16. Endovascular Management of Central Retinal Arterial Occlusion.

    PubMed

    Agarwal, Nitin; Gala, Nihar B; Baumrind, Benjamin; Hansberry, David R; Thabet, Ahmad M; Gandhi, Chirag D; Prestigiacomo, Charles J

    2016-11-01

    Central retinal artery occlusion (CRAO) is an ophthalmologic emergency due to the sudden cessation of circulation to the inner retinal layer. Without immediate treatment, permanent blindness may ensue. Several treatment options exist, ranging from noninvasive medical management to thrombolysis. Nonetheless, ongoing debate exists regarding the best therapeutic strategy. The authors present the case of a 78-year-old woman with a medical history of hypercholesterolemia and rheumatoid arthritis who experienced complete loss of vision in her left eye. Following ophthalmologic evaluation demonstrating left CRAO, anterior chamber paracentesis was performed. Endovascular intervention was performed via local intra-arterial fibrinolysis with alteplase. Her vision returned to 20/20 following the procedure. In general, conventional therapies have not significantly improved patient outcomes. Several management options exist for CRAO. In general, conservative measures have not been reported to yield better patient outcomes as compared to the natural history of this medical emergency. Endovascular approaches are another option as observed with this case reported. In cases of CRAO, therapeutic strategies such as intra-arterial fibrinolysis utilize a local infusion of reactive tissue plasminogen activator directly at the site of occlusion via catheterization of the ophthalmic artery. Although several case series do show promising results after treating CRAO with intra-arterial fibrinolysis, further studies are required given the reports of complications.

  17. Endovascular treatment for traumatic thoracic aortic pseudoaneurysm: a case report

    PubMed Central

    2013-01-01

    Cases of an endovascular treatment for traumatic aortic injury are extremely rare. A prompt diagnosis of traumatic thoracic aortic pseudoaneurysm through a 3-dimensional computed tomographic angiography of aorta and emergency repair are mandatory to rescue the life-threatening condition. An endovascular treatment is a trend for traumatic aortic injury because of lower invasivity, morbidity and mortality. We reported a rare case of traumatic aortic injury with thoracic aortic pseudoaneurysm definitively diagnosed by the reconstructional computed tomographic angiography of aorta and successfully treated with endovascular stent-graft. PMID:23452982

  18. [Management of aortic aneurysms in the endovascular era].

    PubMed

    Gemayel, Gino; Montessuit, Michel; Sierra, Jorge; Lahlaidi Sierra, Nadia; Bednarkiewicz, Marek

    2017-03-01

    Abdominal aortic aneurysm is a disease seen in the elderly. Without intervention, an aneurysm can rupture which leads to death in most cases. Surgical resection was the gold standard treatment for many years but since two decades, endovascular repair has surged drastically. Less invasive and morbid than open repair, this technique has significantly evolved in the recent years. Nowadays the whole aorta can be treated with endovascular techniques in expert hands. This article presents an overview of different endovascular solutions and innovations in the management of aortic aneurysms.

  19. Contemporary Outcomes of Endovascular Intervention for Critical Limb Ischemia.

    PubMed

    Dalal, Pratik K; Prasad, Anand

    2017-04-01

    Critical limb ischemia (CLI) remains a significant cause of morbidity and mortality in patients with peripheral arterial disease. Optimal treatment strategies for CLI remain controversial. The only randomized trial comparing surgical with endovascular revascularization suggests no significant difference in limb salvage between open surgical bypass and angioplasty. Although novel endovascular strategies are now available, their efficacies remain largely untested in a randomized fashion. This review provides an overview of the data surrounding contemporary outcomes of endovascular therapy with an emphasis on current knowledge gaps.

  20. In vivo geometry of the kissing stent and covered endovascular reconstruction of the aortic bifurcation configurations in aortoiliac occlusive disease.

    PubMed

    Groot Jebbink, Erik; Ter Mors, Thijs G; Slump, Cornelis H; Geelkerken, Robert H; Holewijn, Suzanne; Reijnen, Michel Mpj

    2017-01-01

    Objectives Various configurations of kissing stent (KS) configurations exist and patency rates vary. In response the covered endovascular reconstruction of the aortic bifurcation configuration was designed to minimize mismatch and improve outcome. The aim of the current study is to compare geometrical mismatch of kissing stent with the covered endovascular reconstruction of the aortic bifurcation configuration in vivo. Methods Post-operative computed tomographic data and patient demographics from 11 covered endovascular reconstruction of the aortic bifurcation and 11 matched kissing stent patients were included. A free hand region of interest and ellipse fitting method were applied to determine mismatch areas and volumes. Conformation of the stents to the vessel wall was expressed using the D-ratio. Results Patients were mostly treated for Rutherford category 2 and 3 (64%) with a lesion classification of TASC C and D in 82%. Radial mismatch area and volume for the covered endovascular reconstruction of the aortic bifurcation group was significantly lower compared to the kissing stent configuration ( P < 0.05). The D-ratio did not significantly differ between groups. Measurements were performed with good intra-class correlation. There were no significant differences in the post-procedural aortoiliac anatomy. Conclusions The present study shows that radial mismatch exists in vivo and that large differences in mismatch exist, in favour of the covered endovascular reconstruction of the aortic bifurcation configuration. Future research should determine if the decreased radial mismatch results in improved local flow profiles and subsequent clinical outcome.

  1. Current status of endovascular stroke treatment.

    PubMed

    Meyers, Philip M; Schumacher, H Christian; Connolly, E Sander; Heyer, Eric J; Gray, William A; Higashida, Randall T

    2011-06-07

    The management of acute ischemic stroke is rapidly developing.Although acute ischemic stroke is a major cause of adult disability and death, the number of patients requiring emergency endovascular intervention remains unknown, but is a fraction of the overall stroke population. Public health initiatives endeavor to raise public awareness about acute stroke to improve triage for emergency treatment, and the medical community is working to develop stroke services at community and academic medical centers throughout the United States. There is an Accreditation Council for Graduate Medical Education–approved pathway for training in endovascular surgical neuroradiology, the specialty designed to train physicians specifically to treat cerebrovascular diseases. Primary and comprehensive stroke center designations have been defined, yet questions remain about the best delivery model. Telemedicine is available to help community medical centers cope with the complexity of stroke triage and treatment. Should comprehensive care be provided at every community center, or should patients with complex medical needs be triaged to major stroke centers with high-level surgical,intensive care, and endovascular capabilities? Although the answers to these and other questions about stroke care delivery remain unanswered owing to the paucity of empirical data, we are convinced that stroke care regionalization is crucial for delivery of high-quality comprehensive ischemic stroke treatment. A stroke team available 24 hours per day, 7 days per week requires specialty skills in stroke neurology, endovascular surgical neuroradiology, neurosurgery, neurointensive care, anesthesiology, nursing, and technical support for optimal success. Several physician groups with divergent training backgrounds (i.e., interventional neuroradiology, neurosurgery,neurology, peripheral interventional radiology, and cardiology) lay claim to the treatment of stroke patients,particularly the endovascular or

  2. Endovascular Treatment of Multiple HIV-related Aneurysms Using Multilayer Stents

    SciTech Connect

    Euringer, Wulf; Suedkamp, Michael; Rylski, Bartosz; Blanke, Philipp

    2012-08-15

    Complex peripheral aneurysm anatomy with major artery branches in the immediate vicinity and mycotic aneurysm often impede endovascular management using covered stent grafts. The Cardiatis Multilayer Stent (Cardiatis, Isnes, Belgium) is a recently approved innovative stent system for peripheral aneurysm management. Its multilayer design aims at decreasing mean velocity and vorticity within the aneurysm sac to cause thrombus formation while maintaining patency of branching vessels due to laminar flow. We present a case of bilateral subclavian artery aneurysms and perivisceral aortic aneurysms in an AIDS patient successfully treated with the Cardiatis Multilayer Stent at 18 months' follow-up.

  3. Rupture and Migration of an Endovascular Stent in the Brachiocephalic Trunk Causing a Vertebral Steal Syndrome

    SciTech Connect

    Periard, D. Haesler, E.; Hayoz, D.; Von Segesser, L. K.; Qanadli, S. D.

    2008-07-15

    Delayed stent fracture has been observed in many different arteries and may represent a risk factor for restenosis. We describe the case of a delayed rupture of an endovascular brachiocephalic trunk stent. The complete fracture allowed a fragment to migrate distally and tilt, resulting in a hemodynamic pattern similar to that of a prevertebral stenosis with complete inversion of the homolateral vertebral blood flow. The induced vertebral steal syndrome as well as the risk of cerebral embolism was corrected by an aortobrachiocephalic bypass and resection of the ruptured stent.

  4. Comparable mid-term survival in patients undergoing elective fenestrated endovascular aneurysm repair and endovascular aneurysm repair for abdominal aortic aneurysm

    PubMed Central

    Gottsäter, Anders; Acosta, Stefan

    2014-01-01

    Objective: To evaluate mid-term survival in patients undergoing elective fenestrated endovascular aneurysm repair and standard endovascular aneurysm repair for abdominal aortic aneurysm. Methods: Consecutive patients treated from 2007 to 2011 with elective fenestrated endovascular aneurysm repair (n = 81) and endovascular aneurysm repair (n = 201) were evaluated concerning age, cardiovascular medication, comorbidities, and mid-term mortality. Results: Patients in the elective fenestrated endovascular aneurysm repair group were younger than the endovascular aneurysm repair group (p = 0.006). In comparison with the endovascular aneurysm repair group, a lower proportion of patients in the elective fenestrated endovascular aneurysm repair group had diabetes (p = 0.013) and anemia (p = 0.003), and a higher proportion had arterial hypertension (p = 0.009). When entering age, endovascular aneurysm repair or fenestrated endovascular aneurysm repair operation, diabetes, anemia, and hypertension in a Cox regression model, only age (hazard ratio: 1.07; 95% confidence interval: 1.03–1.11; p < 0.001) was a risk factor for mid-term mortality. Conclusion: Careful patient selection and medical optimization resulted in comparable mid-term survival in patients undergoing elective fenestrated endovascular aneurysm repair and endovascular aneurysm repair. PMID:26770700

  5. Brain hemorrhage after endovascular reperfusion therapy of ischemic stroke: a threshold-finding whole-brain perfusion CT study.

    PubMed

    Renú, Arturo; Laredo, Carlos; Tudela, Raúl; Urra, Xabier; Lopez-Rueda, Antonio; Llull, Laura; Oleaga, Laura; Amaro, Sergio; Chamorro, Ángel

    2017-01-01

    Endovascular reperfusion therapy is increasingly used for acute ischemic stroke treatment. The occurrence of parenchymal hemorrhage is clinically relevant and increases with reperfusion therapies. Herein we aimed to examine the optimal perfusion CT-derived parameters and the impact of the duration of brain ischemia for the prediction of parenchymal hemorrhage after endovascular therapy. A cohort of 146 consecutive patients with anterior circulation occlusions and treated with endovascular reperfusion therapy was analyzed. Recanalization was assessed at the end of reperfusion treatment, and the rate of parenchymal hemorrhage at follow-up neuroimaging. In regression analyses, cerebral blood volume and cerebral blood flow performed better than Delay Time maps for the prediction of parenchymal hemorrhage. The most informative thresholds (receiver operating curves) for relative cerebral blood volume and relative cerebral blood flow were values lower than 2.5% of normal brain. In binary regression analyses, the volume of regions with reduced relative cerebral blood volume and/or relative cerebral blood flow was significantly associated with an increased risk of parenchymal hemorrhage, as well as delayed vessel recanalization. These results highlight the relevance of the severity and duration of ischemia as drivers of blood-brain barrier disruption in acute ischemic stroke and support the role of perfusion CT for the prediction of parenchymal hemorrhage.

  6. Endovascular intervention for deep venous thrombosis in patients with inferior vena cava filters.

    PubMed

    Karageorgiou, John; Fowler, Kathryn; Vedantham, Suresh; Saad, Nael

    2016-10-01

    Patients with inferior vena cava (IVC) filter-associated deep venous thrombosis (DVT) are a challenging subset of patients for endovascular intervention. Given the lack of available data pertaining to this clinical scenario, the purpose of this study was to evaluate the authors' experience with the use of endovascular treatment for DVT in patients with IVC filters. Primary aims included assessing the technical and clinical success, complications, and clinical patency in these patients. This was a retrospective single-center review of adult patients with IVC filters undergoing endovascular treatment of DVT between 1/2005 and 4/2014. Patient electronic medical records were reviewed for demographic data, anticoagulation status, symptoms, symptomatic extremities, extent of thrombosis, therapies received, technical and clinical success, and complications. Query yielded 82 patients (mean 53 years, range 18-96; 66% male), all of whom were included in our analysis. The majority of patients presented with lower extremity pain and swelling, with extensive clot burden despite the use of anticoagulant medication. Treatment elements utilized included pharmacologic lysis in 92%, mechanical thrombectomy in 77%, angioplasty in 63% and stent placement in 50% of patients. Interventions were technically successful in restoring flow in 87% of patients, and clinically successful in improving presenting symptoms in 79% of patients. By SIR criteria, 24% of patients experienced complications (categorized as 10% minor and 14% major). There were two deaths from intracranial hemorrhage. The probability of thrombosis-free survival at 1, 3, 6, 9 and 12 months was 0.85 (CI 0.74-0.93), 0.81 (CI 0.69-0.89), 0.74 (CI 0.62-0.83), 0.70 (CI 0.57-0.8) and 0.70 (CI 0.57-0.8), respectively. Endovascular interventions are usually effective in relieving symptoms in patients with DVT and pre-existing IVC filters. However, these outcomes are achieved with significant complication rates that may exceed those

  7. Distal landing zone open fenestration facilitates endovascular elephant trunk completion and false lumen thrombosis.

    PubMed

    Roselli, Eric E; Sepulveda, Edgardo; Pujara, Akshat C; Idrees, Jahanzaib; Nowicki, Edward

    2011-12-01

    Controversy surrounds the endovascular treatment of chronic dissection because of inconsistent remodeling of the aorta. The purpose of this study was to assess efficacy and safety of a novel technique for repairing aneurysmal change associated with chronic descending aortic dissection. From July 2007 to April 2011, 24 patients with descending aortic aneurysmal change, consequent to previously repaired ascending aortic dissection or medically treated descending dissection, underwent combined open first-stage elephant trunk (ET) insertion and fenestration of the descending aorta intimal flap. Second-stage ET endovascular completion was performed with the index operation in 4 patients and later in 20 patients (median, 62 days). Repair was elective in 14 patients and urgent in 10 patients. Concomitant procedures were aortic valve replacement in 3 patients and coronary revascularization in 3 patients, and 16 procedures were reoperations. Chart review and analysis of 3-dimensional computed tomography (CT) scans were performed. Imaging follow-up was complete in 89% of patients during a median of 18 months (interquartile range [IQR], 10 to 28 months). Technical success was achieved in all patients. Moderate reduction in aortic size occurred in most patients, with no retrograde false lumen flow. Late reintervention was required in 5 patients: endovascular for distal type I endoleak in 2 patients, type II endoleak in 1 patient, pseudoaneurysm of the abdominal aorta in 1 patient, and 1 open repair for aneurysm of the untreated distal segment in 1 patient. One patient died of pulmonary embolism on postoperative day 19 after 1-stage repair (4.0%) and 1 patient (4%) had a transient stroke, but there was no renal failure, respiratory failure, or permanent spinal cord injury. Median length of stay was 13 days (IQR, 8 to 16 days) after first-stage ET and 8 days (IQR, 5 to 12 days) after endovascular ET completion. One patient died during a mean of 23 ± 11 months of follow-up. Open

  8. Standards for Endovascular Neurosurgical Training and Certification of the Society of Korean Endovascular Neurosurgeons 2013

    PubMed Central

    Shin, Dong-Seong; Park, Sukh-Que; Kang, Hyun-Seung; Yoon, Seok-Mann; Cho, Jae-Hoon; Lim, Dong-Jun; Baik, Min-Woo; Kwon, O Ki

    2014-01-01

    The need for standard endovascular neurosurgical (ENS) training programs and certification in Korea cannot be overlooked due to the increasing number of ENS specialists and the expanding ENS field. The Society of Korean Endovascular Neurosurgeons (SKEN) Certification Committee has prepared training programs and certification since 2010, and the first certificates were issued in 2013. A task force team (TFT) was organized in August 2010 to develop training programs and certification. TFT members researched programs and systems in other countries to develop a program that best suited Korea. After 2 years, a rough draft of the ENS training and certification regulations were prepared, and the standard training program title was decided. The SKEN Certification Committee made an official announcement about the certification program in March 2013. The final certification regulations comprised three major parts: certified endovascular neurosurgeons (EN), certified ENS institutions, and certified ENS training institutions. Applications have been evaluated and the results were announced in June 2013 as follows: 126 members received EN certification and 55 hospitals became ENS-certified institutions. The SKEN has established standard ENS training programs together with a certification system, and it is expected that they will advance the field of ENS to enhance public health and safety in Korea. PMID:24851145

  9. Percutaneous Endovascular Treatment for Hepatic Artery Stenosis after Liver Transplantation: The Role of Percutaneous Endovascular Treatment

    PubMed Central

    Vidjak, Vinko; Novačić, Karlo; Matijević, Filip; Kavur, Lovro; Slavica, Marko; Mrzljak, Anna; Filipec-Kanižaj, Tajana; Leder, Nikola Ivan; Škegro, Dinko

    2015-01-01

    Summary Background To retrospectively analyze the outcomes of interventional radiology treatment of patients with hepatic artery stenosis (HAS) after liver transplantation at our Institution. Material/Methods Hepatic artery stenosis was diagnosed and treated by endovascular technique in 8 (2.8%) patients, who underwent liver transplantation between July 2007 and July 2011. Patients entered the follow-up period, during which we analyzed hepatic artery patency with Doppler ultrasound at 1, 3, 6, and 12 months after percutaneous endovascular treatment (PTA), and every six months thereafter. Results During the 12-month follow-up period, 6 out of 8 patients (75%) were asymptomatic with patent hepatic artery, which was confirmed by multislice computed tomography (MSCT) angiography, or color Doppler (CD) ultrasound. One patient had a fatal outcome of unknown cause, and one patient underwent orthotopic liver retransplantation (re-OLT) procedure due to graft failure. Conclusions Our results suggest that HAS angioplasty and stenting are minimally invasive and safe endovascular procedures that represent a good alternative to open surgery, with good 12-month follow-up patency results comparable to surgery. PMID:26150902

  10. [Color Doppler evaluation and diagnosis of local complications after arterial endovascular procedures].

    PubMed

    Novelli, Marco; Righi, Daniele; Pilato, Alida

    2012-09-01

    Diagnostic and therapeutic percutaneous endovascular procedures have become more and more common in recent years, and so also the number of local complications has increased. After such procedures a simple clinical examination may show the presence of an inguinal mass, but does not permit a diagnosis, while Color Doppler and Duplex Scanner can make a differential diagnosis between hematoma, pseudoaneurysm, arteriovenous fistula or other disease. Color Doppler is ubiquitously used to diagnose such complications as it offers a low-cost, easy-to-use method, only minimally uncomfortable for the patient. This ultrasound system can provide both anatomic and haemodynamic information. Our study highlights the diagnostic possibilities offered by the Color Doppler and Duplex Scanner and details, using many illustrations and examples, how the most common complications such as hematoma, pseudoaneurysm, arteriovenous fistula and thrombosis are imaged. Hematoma appears as a hypoechogenic zone, with no color inside, as flow is not present. Pseudoaneurysms, unlike hematoma, maintain a connection with an injured blood vessel, and so they show blood flow both inside the lesion and in the communicating channel, with a typical pattern. The arteriovenous fistula is a vascular channel created, after a percutaneous procedure, between an artery and an adjacent vein that have both been damaged. An endovascular thrombus is directly shown as a luminal defect of flow. Other less common complications are discussed and illustrated.

  11. Endovascular Treatment of Cerebral Aneurysm with Coils and Onyx

    PubMed Central

    Ueno, J.; Tohma, N.

    2004-01-01

    Summary We investigated endovascular treatment of cerebral aneurysm by coil and Onyx in vivo experiment in order to promote the advantages of coil embolization,. The aim of this study was to clarify the advantages and problems of coil and Onyx embolization and to evaluate its potentials for application in clinical medicine. We set experimental aneurysms made of external jugular vein to bilateral carotid arteries of 10 Beagle dogs and embolized aneurysm with coils and Onyx. Two months later, the dogs were sacrificed and took out the experimental aneurysms and examined them histologically. We have experienced Onyx migration into the vessel at the beginning of our experiment. Technical problems were as follows; Onyx was not easily visible on DSA monitor particularly in tight coil packing. Catheter tip was often stuck to the Onyx in the aneurysm. Protect balloon could not completely protect the Onyx leakage into the vessel. Microscopic examinations were as follows; The aneurysm was filled with Onyx, coils, and inflammatory reactants. The orifice of the aneurysm was packed with augmented fibrous tissue. 1. This method increased contact between the aneurysm wall and coils. 2. Onyx filled the intra-aneurismal space more tightly. 3. Coils prevented Onyx from flowing out into the vessel. 4. In Onyx, intimal layer was more rapidly formed at the neck of the aneurysm than coils only. 5. The most important problems during Onyx embolization is how to prevent Onyx migration into the vessel. We should like to propose the guideline for Onyx embolization. PMID:20587272

  12. Imaging After Nellix Endovascular Aneurysm Sealing: A Consensus Document.

    PubMed

    Holden, Andrew; Savlovskis, Janis; Winterbottom, Andrew; van den Ham, Leo H; Hill, Andrew; Krievins, Dainis; Hayes, Paul D; Reijnen, Michel M P J; Böckler, Dittmar; de Vries, Jean-Paul P M; Carpenter, Jeffrey P; Thompson, Matt M

    2016-02-01

    Endovascular aneurysm sealing (EVAS) using the Nellix system is a new and different method of abdominal aortic aneurysm repair. Normal postoperative imaging has unique appearances that change with time; complications also have different and specific appearances. This consensus document on the imaging findings after Nellix EVAS is based on the collective experience of the sites involved in the Nellix EVAS Global Forward Registry and the US Investigational Device Exemption Trial. The normal findings on computed tomography (CT), duplex ultrasound, magnetic resonance imaging, and plain radiography are described. With time, endobag appearances change on CT due to contrast migration to the margins of the hydrogel polymer within the endobag. Air within the endobag also has unique appearances that change over time. Among the complications after Nellix EVAS, type I endoleak usually presents as a curvilinear area of flow between the endobag and aortic wall, while type II endoleak is typically small and usually occurs where an aortic branch artery lies adjacent to an irregular aortic blood lumen that is not completely filled by the endobag. Procedural aortic injury is an uncommon but important complication that occurs as a result of overfilling of the endobags during Nellix EVAS. The optimum imaging surveillance algorithm after Nellix EVAS has yet to be defined but is largely CT-based, especially in the first year postprocedure. However, duplex ultrasound also appears to be a sensitive modality in identifying normal appearances and complications.

  13. Formation, characterization, and flow dynamics of nanostructure modified sensitive and selective gas sensors based on porous silicon

    NASA Astrophysics Data System (ADS)

    Ozdemir, Serdar

    Nanopore covered microporous silicon interfaces have been formed via an electrochemical etch for gas sensor applications. Rapid reversible and sensitive gas sensors have been fabricated. Both top-down and bottom-up approaches are utilized in the process. A nano-pore coated micro-porous silicon surface is modified selectively for sub-ppm detection of NH3, PH3 , NO, H2S, SO2. The selective depositions include electrolessly generated SnO2, CuxO, Au xO, NiO, and nanoparticles such as TiO2, MgO doped TiO 2, Al2O3, and ZrO2. Flow dynamics are analyzed via numerical simulations and response data. An array of sensors is formed to analyze mixed gas response. A general coating selection method for chemical sensors is established via an extrapolation on the inverse of the Hard-Soft Acid-Base concept. In Chapter 1, the current state of the porous silicon gas sensor research is reviewed. Since metal oxide thin films, and, recently, nanowires are dominantly used for sensing application, the general properties of metal oxides are also discussed in this chapter. This chapter is concluded with a discussion about commercial gas sensors and the advantages of using porous silicon as a sensing material. The PS review discussed at the beginning of this chapter is an overview of the following publication: (1) "The Potential of Porous Silicon Gas Sensors", Serdar Ozdemir, James L. Gole, Current Opinion in Solid State and Materials Science, 11, 92-100 (2007). In Chapter 2, porous silicon formation is explained in detail. Interesting results of various silicon anodization experiments are discussed. In the second part of this chapter, the microfabrication process of porous silicon conductometric gas sensors and gas testing set up are briefly introduced. In chapter 3, metal oxide nanoparticle/nanocluster formation and characterization experiments via SEM and XPS analysis are discussed. Chapter 4 is an overview of the test results for various concentrations NH3, NO, NO2 and PH3. The

  14. The evolution of endovascular electroencephalography: historical perspective and future applications.

    PubMed

    Sefcik, Roberta K; Opie, Nicholas L; John, Sam E; Kellner, Christopher P; Mocco, J; Oxley, Thomas J

    2016-05-01

    Current standard practice requires an invasive approach to the recording of electroencephalography (EEG) for epilepsy surgery, deep brain stimulation (DBS), and brain-machine interfaces (BMIs). The development of endovascular techniques offers a minimally invasive route to recording EEG from deep brain structures. This historical perspective aims to describe the technical progress in endovascular EEG by reviewing the first endovascular recordings made using a wire electrode, which was followed by the development of nanowire and catheter recordings and, finally, the most recent progress in stent-electrode recordings. The technical progress in device technology over time and the development of the ability to record chronic intravenous EEG from electrode arrays is described. Future applications for the use of endovascular EEG in the preoperative and operative management of epilepsy surgery are then discussed, followed by the possibility of the technique's future application in minimally invasive operative approaches to DBS and BMI.

  15. Endovascular surgery for peripheral arterial occlusive disease. A critical review.

    PubMed Central

    Ahn, S S; Eton, D; Moore, W S

    1992-01-01

    Endovascular surgery is a new multidisciplinary field that applies the recently innovated techniques of angioscopy, intraluminal ultrasound, balloon angioplasty, laser, mechanical atherectomy, and stents. This field can be defined as a diagnostic and therapeutic discipline that uses catheter-based systems to treat vascular disease. As such, it integrates the subspecialties of vascular surgery, interventional radiology, interventional cardiology, and biomedical engineering for the common purpose of improving arterial hemodynamics. Endovascular surgery offers many potential benefits: long incisions are replaced with a puncture wound, the need for postoperative intensive care is significantly reduced, major cardiac and pulmonary complications from general anesthesia are side stepped, and the dollar savings could be dramatic as the need for intensive care unit and in-hospital stay diminishes. Despite these technological advancements, endovascular surgery is still in its infancy and currently has limited applications. This review provides an updated summary of endovascular surgery today and addresses some of the obstacles still preventing its widespread use. PMID:1385944

  16. Current Status and Future Prospect of Endovascular Neurosurgery

    PubMed Central

    Jeon, Young Il

    2008-01-01

    Recently, due to the evolution of technology, the field of neurosurgery is receiving spotlight. In particular endovascular neurosurgery has gained a great interest along with the advancement of the modern neurosurgery. The most remarkable advances were made in embolization of the cerebral aneurysms, arteriovenous malformations and intracranial stenosis during the past 10 years. These advances will further change the role of neurosurgeons in treating cerebrovascular disease. Because interventional neuroradiologists have performed most of procedures in the past, neurosurgeons have been deprived of chances to learn endovascular procedure. This article discusses the development of technological aspect of endovascular neurosurgery in chronological order. By understanding the history and current status of the endovascular surgery, the future of neurosurgery will be promising. PMID:19096608

  17. Endovascular Management of an Infected Superficial Femoral Artery Pseudoaneurysm

    SciTech Connect

    Damodharan, Karthik Beckett, David

    2013-10-15

    This article describes an endovascular technique of treating an infected pseudoaneurysm by direct thrombin injection via a catheter placed inside the aneurysm sac while maintaining temporary balloon occlusion of the neck of the false aneurysm.

  18. Endovascular Treatment of Vertebro-Vertebral Arteriovenous Fistula

    PubMed Central

    Briganti, F.; Tedeschi, E.; Leone, G.; Marseglia, M.; Cicala, D.; Giamundo, M.; Napoli, M.; Caranci, F.

    2013-01-01

    This report describes endovascular approaches for occlusion of vertebro-vertebral arteriovenous fistula (W-AVF) in a series of three cases and a review of the literature. Complete neuroimaging assessment, including CT, MR and DSA was performed in three patients (two female, one male) with W-AVF. Based on DSA findings, the W-AVF were occluded by endovascular positioning of detachable balloons (case 1), coils (case 2), or a combination of both (case 3) with parent artery patency in two out of three cases. In this small series, endovascular techniques for occlusion of W-AVF were safe and effective methods of treatment. To date, there are no guidelines on the best treatment for W-AVF. Detachable balloons, endovascular coiling, combined embolization procedures could all be considered well-tolerated treatments. PMID:23859293

  19. Developing practice recommendations for endovascular revascularization for acute ischemic stroke

    PubMed Central

    Lazzaro, Marc A.; Alexandrov, Andrei V.; Darkhabani, Ziad; Edgell, Randall C.; English, Joey; Frei, Donald; Jamieson, Dara G.; Janardhan, Vallabh; Janjua, Nazli; Janjua, Rashid M.; Katzan, Irene; Khatri, Pooja; Kirmani, Jawad F.; Liebeskind, David S.; Linfante, Italo; Nguyen, Thanh N.; Saver, Jeffrey L.; Shutter, Lori; Xavier, Andrew; Yavagal, Dileep; Zaidat, Osama O.

    2012-01-01

    Guidelines have been established for the management of acute ischemic stroke; however, specific recommendations for endovascular revascularization therapy are lacking. Burgeoning investigation of endovascular revascularization therapies for acute ischemic stroke, rapid device development, and a diverse training background of the providers performing the procedures underscore the need for practice recommendations. This review provides a concise summary of the Society of Vascular and Interventional Neurology endovascular acute ischemic stroke roundtable meeting. This document was developed to review current clinical efficacy of pharmacologic and mechanical revascularization therapy, selection criteria, periprocedure management, and endovascular time metrics and to highlight current practice patterns. It therefore provides an outline for the future development of multisociety guidelines and recommendations to improve patient selection, procedural management, and organizational strategies for revascularization therapies in acute ischemic stroke. PMID:23008406

  20. Endovascular treatment of hemodialysis access pseudoaneurysms.

    PubMed

    Shah, Aamir S; Valdes, Jaime; Charlton-Ouw, Kristofer M; Chen, Zhongxue; Coogan, Sheila M; Amer, Hammad M; Estrera, Anthony L; Safi, Hazim J; Azizzadeh, Ali

    2012-04-01

    Pseudoaneurysm (PSA) formation is a complication of hemodialysis access. Open repair requires PSA resection, interposition graft placement, and insertion of a catheter as a bridge. Endovascular stent graft repair is an alternative that permits immediate use of the access site. The objective of this study was to determine the efficacy of stent grafts for repair of arteriovenous fistula and arteriovenous graft PSA. A retrospective review of medical records from October 2007 to March 2011 revealed 24 patients with a PSA who underwent endovascular repair using a stent graft. Indications for repair included PSA with symptoms (n = 11), PSA with skin erosion (n = 8), PSA with failed hemodialysis (n = 3), and PSA after balloon angioplasty of a stenosis (n = 2). Outcome measures were technical success, 30-day and 180-day patency, secondary interventions, and complications. All the statistical analyses were conducted by using software SAS 9.1 (SAS, SAS Institute, Gary, NC). Twenty-seven self-expanding stent grafts (Viabahn, W. L. Gore, n = 25; Fluency, Bard, n = 2) were used to treat hemodialysis access (arteriovenous graft, n = 13; arteriovenous fistula, n = 11) PSA in 24 patients (16 females; mean age, 55.7 years; mean body mass index, 28.4; mean PSA diameter, 19.5 mm). Comorbidities included hypertension (n = 22; 91.7%), diabetes mellitus (n = 8; 33.3%), and coronary artery disease (n = 4; 16.67%). The median time from access creation to repair was 455 days. The technical success rate was 100%. Balloon angioplasty of an outflow stenosis was performed in 56% of stent grafts. The 30- and 180-day patency rate was 100% and 69.2%, respectively. Three secondary interventions were performed for treatment of unrelated stenosis. Treatment failure occurred in five (18.5%) stent grafts due to infection (n = 3) and thrombosis (n = 2). Treatment of PSA with skin erosion was associated with failure due to infection (odds ratio, 5.0; 95% confidence interval, .38, 66.01). The remaining

  1. Endovascular extraction techniques for pacemaker and ICD lead extraction

    PubMed Central

    Bracke, F.A.; Meijer, A.; van Gelder, B.

    2001-01-01

    In the last few years, comprehensive endovascular techniques have been developed to extract chronically implanted pacemaker and defibrillator leads. It is important that referring physician have knowledge of the advantages and limitations of the different techniques. In this paper we discuss the techniques and results of the currently used endovascular extraction techniques. ImagesFigure 1Figure 2Figure 3Figure 4Figure 5Figure 6Figure 7 PMID:25696690

  2. Antithrombotic Strategies in Endovascular Interventions: Current Status and Future Directions.

    PubMed

    Shishehbor, Mehdi H; Katzen, Barry T

    2013-10-01

    Despite increasing numbers of endovascular interventions to treat arterial and venous disease, scant level 1 evidence is available regarding the role of antithrombotic and antiplatelet therapy in patients undergoing these procedures. The current practice in this regard is heterogeneous and has mainly been driven by data from coronary artery disease and percutaneous coronary intervention. This article discusses the role of antithrombotic and antiplatelet agents for endovascular intervention. Copyright © 2013 Elsevier Inc. All rights reserved.

  3. Evidence for Endovascular Simulation Training: A Systematic Review.

    PubMed

    See, K W M; Chui, K H; Chan, W H; Wong, K C; Chan, Y C

    2016-03-01

    Simulation training in endovascular surgery provides opportunities for trainees to practice and learn from non-patient based experience. Several types of endovascular simulators are available commercially. Previous studies on endovascular simulation training can be categorized into trials in which only a simulator was used when measuring performance metrics or "trials within simulation"; patient specific procedure rehearsals; and randomized, controlled trials (RCTs) or translational studies. To examine whether endovascular simulation training can improve surgeon techniques and patient outcomes in real clinical settings. A literature review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. All searches were done via PubMed and Embase. Review articles, and papers that were not related to endovascular surgery and not within the scope of interest were excluded. References of review articles were further screened according to the exclusion criteria. In total, 909 records were identified and 290 duplicates were removed. Thirty-one were included in the qualitative analysis. Twenty-three were trials within simulation and most of them found statistically significant improvements in procedure time, fluoroscopy time, and contrast volume. Five were patient specific procedure rehearsals and showed that simulation significantly affected the fluoroscopy angle and improved performance metrics. Three were RCTs and revealed mainly positive results on a Global Rating Scale and procedure specific rating scale. Contemporary evidence shows that performance metrics within endovascular simulations improve with simulation training. Successful translation to in vivo situations is observed in patient specific procedure rehearsals and RCTs on real procedures. However, there is no level I evidence to show that predictive validity of simulation can definitively improve patient outcomes. Current literature supports the idea that

  4. Angiographic outcome of endovascular stroke therapy correlated with MR findings, infarct growth, and clinical outcome in the DEFUSE 2 trial.

    PubMed

    Marks, Michael P; Lansberg, Maarten G; Mlynash, Michael; Kemp, Stephanie; McTaggart, Ryan A; Zaharchuk, Greg; Bammer, Roland; Albers, Gregory W

    2014-10-01

    DEFUSE 2 demonstrated that patients with magnetic resonance imaging mismatch had a favorable clinical response to tissue reperfusion assessed by magnetic resonance imaging. This study reports the endovascular results and correlates angiographic reperfusion with clinical and imaging outcomes. Prospectively enrolled ischemic stroke patients underwent baseline magnetic resonance imaging and started endovascular therapy within 12 h of onset. Patients were classified as either target mismatch or no target mismatch using magnetic resonance imaging. The pre- and postprocedure angiogram was evaluated to determine thrombolysis in cerebral infarction scores. Favorable clinical response was determined at day 30, and good functional outcome was defined as a modified Rankin Scale 0-2 at day 90. One-hundred patients had attempted endovascular treatment. At procedure end, 23% were thrombolysis in cerebral infarction 0-1, 31% thrombolysis in cerebral infarction 2A, 28% thrombolysis in cerebral infarction 2B, and 18% thrombolysis in cerebral infarction 3. More favorable thrombolysis in cerebral infarction-reperfusion scores were associated with greater magnetic resonance imaging reperfusion (P<0·001). thrombolysis in cerebral infarction scores correlated with 30-day favorable clinical response (P=0·041) and 90-day modified Rankin Scale 0-2 (P=0·008). These correlations were significant for target mismatch patients at 30 days (P=0·034) and 90 days (P=0·003). Infarct growth was strongly associated with poorer thrombolysis in cerebral infarction scores in target mismatch patients (P<0·001). Patients with thrombolysis in cerebral infarctionnfarction 2A reperfusion had less magnetic resonance imaging reperfusion (P=0·004) and poorer clinical outcome at 90 days (P=0·01) compared with thrombolysis in cerebral infarction 2B-3 patients. Thrombolysis in cerebral infarction reperfusion following endovascular therapy for ischemic stroke is highly correlated with magnetic resonance

  5. Evolution of endovascular mechanical thrombectomy for acute ischemic stroke

    PubMed Central

    Przybylowski, Colin J; Ding, Dale; Starke, Robert M; Durst, Christopher R; Crowley, R Webster; Liu, Kenneth C

    2014-01-01

    Acute ischemic stroke (AIS) is a common medical problem associated with significant morbidity and mortality worldwide. A small proportion of AIS patients meet eligibility criteria for intravenous thrombolysis (IVT) with recombinant tissue plasminogen activator, and its efficacy for large vessel occlusion is poor. Therefore, an increasing number of patients with AIS are being treated with endovascular mechanical thrombectomy when IVT is ineffective or contraindicated. Rapid advancement in catheter-based and endovascular device technology has led to significant improvements in rates of cerebral reperfusion with these devices. Stentrievers and modern aspiration catheters have now surpassed earlier generation devices in the degree and rapidity of revascularization. This progress has been achieved with no concurrent increase in risk of major complications or mortality, both when used alone or in combination with IVT. The initial randomized controlled trials comparing endovascular therapy to IVT for AIS failed to show superior outcomes with endovascular treatment, but key limitations of each trial may limit the significance of these results to current practice. While endovascular devices and operator experience continue to evolve, we are optimistic that this will be accompanied by improvements in patient outcomes. This review highlights the major endovascular devices used in current practice and the trials which have investigated their efficacy. PMID:25405185

  6. Evolution of endovascular mechanical thrombectomy for acute ischemic stroke.

    PubMed

    Przybylowski, Colin J; Ding, Dale; Starke, Robert M; Durst, Christopher R; Crowley, R Webster; Liu, Kenneth C

    2014-11-16

    Acute ischemic stroke (AIS) is a common medical problem associated with significant morbidity and mortality worldwide. A small proportion of AIS patients meet eligibility criteria for intravenous thrombolysis (IVT) with recombinant tissue plasminogen activator, and its efficacy for large vessel occlusion is poor. Therefore, an increasing number of patients with AIS are being treated with endovascular mechanical thrombectomy when IVT is ineffective or contraindicated. Rapid advancement in catheter-based and endovascular device technology has led to significant improvements in rates of cerebral reperfusion with these devices. Stentrievers and modern aspiration catheters have now surpassed earlier generation devices in the degree and rapidity of revascularization. This progress has been achieved with no concurrent increase in risk of major complications or mortality, both when used alone or in combination with IVT. The initial randomized controlled trials comparing endovascular therapy to IVT for AIS failed to show superior outcomes with endovascular treatment, but key limitations of each trial may limit the significance of these results to current practice. While endovascular devices and operator experience continue to evolve, we are optimistic that this will be accompanied by improvements in patient outcomes. This review highlights the major endovascular devices used in current practice and the trials which have investigated their efficacy.

  7. [Hybrid operating rooms: only for advanced endovascular procedures?].

    PubMed

    Verhoeven, E; Katsargyris, A; Töpel, I; Steinbauer, M

    2013-10-01

    The evolution of endovascular techniques has led to the concept of the "hybrid operating room" (hybrid OR). A hybrid OR combines the sterility of an OR in an operating theatre environment with a high-quality fixed imaging system. On the basis of these advantages it would be desirable that an angio-hybrid OR becomes a standard requirement for endovascular surgery. In Great Britain guidelines have already been published that require a hybrid OR even for normal endovascular management of the infrarenal aorta. However, in Germany there are no guidelines from professional societies or formal rules from the federal joint committee, thus in this article a classification of endovascular procedures according to their complexity and the necessary infrastructures are proposed in order to define particular procedures that should only be performed in an angio-hybrid OR. According to our experience, endovascular procedures can be classified into four categories based on their complexity and the requirements regarding fluoroscopy: level 1: standard EVAR, TEVAR, iliac and popliteal artery procedures; level 2: iliac branched (IBD) and standard (2 fenestrations for the renal arteries and a scallop for the superior mesenteric artery) fenestrated stent-grafting; level 3: more complex fenestrated procedures (three or four fenestrations); and level 4: branched stent-grafting for TAAA. At this moment it is still acceptable to perform level 1 and level 2 procedures outside of a hybrid OR. In our opinion, it is not recommended to perform level 3 and level 4 endovascular procedures without a hybrid OR.

  8. Endovascular treatment versus medical care alone for ischaemic stroke: systematic review and meta-analysis

    PubMed Central

    Neves, Joana Briosa; Caldeira, Daniel; Ferro, José M; Ferreira, Joaquim J; Costa, João

    2016-01-01

    Objectives To evaluate the efficacy and safety of endovascular treatment, particularly adjunctive intra-arterial mechanical thrombectomy, in patients with ischaemic stroke. Design Systematic review and meta-analysis. Data sources Medline, Embase, Cochrane Central Register of Controlled Trials, Web of Science, SciELO, LILACS, and clinical trial registries from inception to December 2015. Reference lists were crosschecked. Eligibility criteria for selecting studies Randomised controlled trials in adults aged 18 or more with ischaemic stroke comparing endovascular treatment, including thrombectomy, with medical care alone, including intravenous recombinant tissue plasminogen activator (rt-PA). Trial endpoints were functional outcome (modified Rankin scale scores of ≤2) and mortality at 90 days after onset of symptoms. No language or time restrictions applied. Results 10 randomised controlled trials (n=2925) were included. In pooled analysis endovascular treatment, including thrombectomy, was associated with a higher proportion of patients experiencing good (modified Rankin scale scores ≤2) and excellent (scores ≤1) outcomes 90 days after stroke, without differences in mortality or rates for symptomatic intracranial haemorrhage, compared with patients randomised to medical care alone, including intravenous rt-PA. Heterogeneity was high among studies. The more recent studies (seven randomised controlled trials, published or presented in 2015) proved better suited to evaluate the effect of adjunctive intra-arterial mechanical thrombectomy on its index disease owing to more accurate patient selection, intravenous rt-PA being administered at a higher rate and earlier, and the use of more efficient thrombectomy devices. In most of these studies, more than 86% of the patients were treated with stent retrievers, and rates of recanalisation were higher (>58%) than previously reported. Subgroup analysis of these seven studies yielded a risk ratio of 1.56 (95

  9. Endovascular image-guided interventions (EIGIs)

    PubMed Central

    Rudin, Stephen; Bednarek, Daniel R.; Hoffmann, Kenneth R.

    2009-01-01

    Minimally invasive interventions are rapidly replacing invasive surgical procedures for the most prevalent human disease conditions. X-ray image-guided interventions carried out using the insertion and navigation of catheters through the vasculature are increasing in number and sophistication. In this article, we offer our vision for the future of this dynamic field of endovascular image-guided interventions in the form of predictions about (1) improvements in high-resolution detectors for more accurate guidance, (2) the implementation of high-resolution region of interest computed tomography for evaluation and planning, (3) the implementation of dose tracking systems to control patient radiation risk, (4) the development of increasingly sophisticated interventional devices, (5) the use of quantitative treatment planning with patient-specific computer fluid dynamic simulations, and (6) the new expanding role of the medical physicist. We discuss how we envision our predictions will come to fruition and result in the universal goal of improved patient care. PMID:18293585

  10. Intraportal endovascular ultrasonography for pancreatic cancer.

    PubMed

    Kaneko, T; Nakao, A; Takagi, H

    1998-01-01

    Intraportal endovascular ultrasonography (IPEUS) is a new diagnostic procedure for pancreatic cancer. In portal invasion, subtle invasion and compression are difficult to differentiate with conventional imaging techniques such as computed tomography and angiography. IPEUS is performed with an 8-French, 20-MHz intravascular ultrasound catheter. IPEUS provides high-resolution, real-time images perpendicular to the portal vein axis. With IPEUS, the portal vein wall is visualized as an echogenic band. A subtle portal invasion can be detected by observing this portal vein wall. Moreover, the segment II of the extrapancreatic nerve plexus is visualized as an echogenic area around the inferior pancreaticoduodenal artery (IPDA). The extrapancreatic nerve plexus invasion can be diagnosed as low echoic infiltration of the area around the IPDA. In the diagnosis of portal vein and extrapancreatic nerve plexus invasion, IPEUS provides a good diagnostic value and important information for the staging of local extension of the pancreatic cancer.

  11. Endovascular Treatment of an Aortoiliac Tuberculous Pseudoaneurysm

    SciTech Connect

    Villegas, Miguel O.; Mereles, Alberto Perez; Tamashiro, Gustavo A.; Dini, Andres E.; Mollon, Ana P.; De Candido, Laura V.; Zelaya, Denis A.; Soledispa-Suarez, Carlos I.; Denato, Sergio; Tamashiro, Alberto; Diaz, Jose A.

    2013-04-15

    We report a rare case of a tuberculous mycotic aortoiliac pseudoaneurysm treated with an endovascular procedure and follow-up of 36 months. The patient was a white 72-year-old man with pulmonary tuberculosis and a former smoker with hypertension, chronic renal failure, and dyslipidemia. A computed tomographic scan of the abdomen and pelvis revealed a left paravertebral cavity with fluid content and involvement of vertebrae L2-L4. After a surgical repair attempt, the patient was treated with the implant of a bifurcated endoprosthesis. Because it is unlikely that any center has extensive experience in the management of this rare manifestation of the disease, we reviewed the literature for similar cases.

  12. Pathogenesis of Thromboembolism and Endovascular Management.

    PubMed

    Behravesh, Sasan; Hoang, Peter; Nanda, Alisha; Wallace, Alex; Sheth, Rahul A; Deipolyi, Amy R; Memic, Adnan; Naidu, Sailendra; Oklu, Rahmi

    2017-01-01

    Venous thromboembolism (VTE), a disease that includes deep venous thrombosis (DVT) and pulmonary embolism (PE), is associated with high mortality, morbidity, and costs. It can result in long-term complications that include postthrombotic syndrome (PTS) adding to its morbidity. VTE affects 1/1000 patients, costs $13.5 billion annually to treat, and claims 100,000 lives annually in the US. The current standard of care for VTE is anticoagulation, though thrombolysis may be performed in patients with PE and threatened limb. This review discusses pathogenesis and medical treatment of VTE and then focuses on endovascular treatment modalities. Mechanical- and catheter-directed thrombolysis (CDT) is discussed, as well as patient selection criteria, and complications. The first prospective study (CaVenT) comparing CDT with anticoagulation alone in acute DVT, despite study shortcomings, corroborates the existing literature indicating improved outcomes with CDT. The potential of the ongoing prospective, multicenter, randomized ATTRACT trial is also highlighted.

  13. Acute Iliac Artery Rupture: Endovascular Treatment

    SciTech Connect

    Chatziioannou, A.; Mourikis, D.; Katsimilis, J.; Skiadas, V. Koutoulidis, V.; Katsenis, K.; Vlahos, L.

    2007-04-15

    The authors present 7 patients who suffered iliac artery rupture over a 2 year period. In 5 patients, the rupture was iatrogenic: 4 cases were secondary to balloon angioplasty for iliac artery stenosis and 1 occurred during coronary angioplasty. In the last 2 patients, the rupture was secondary to iliac artery mycotic aneurysm. Direct placement of a stent-graft was performed in all cases, which was dilated until extravasation was controlled. Placement of the stent-graft was successful in all the cases, without any complications. The techniques used, results, and mid-term follow-up are presented. In conclusion, endovascular placement of a stent-graft is a quick, minimally invasive, efficient, and safe method for emergency treatment of acute iliac artery rupture, with satisfactory short- and mid-term results.

  14. Pathogenesis of Thromboembolism and Endovascular Management

    PubMed Central

    Behravesh, Sasan; Hoang, Peter; Nanda, Alisha; Wallace, Alex; Sheth, Rahul A.; Deipolyi, Amy R.; Memic, Adnan; Naidu, Sailendra

    2017-01-01

    Venous thromboembolism (VTE), a disease that includes deep venous thrombosis (DVT) and pulmonary embolism (PE), is associated with high mortality, morbidity, and costs. It can result in long-term complications that include postthrombotic syndrome (PTS) adding to its morbidity. VTE affects 1/1000 patients, costs $13.5 billion annually to treat, and claims 100,000 lives annually in the US. The current standard of care for VTE is anticoagulation, though thrombolysis may be performed in patients with PE and threatened limb. This review discusses pathogenesis and medical treatment of VTE and then focuses on endovascular treatment modalities. Mechanical- and catheter-directed thrombolysis (CDT) is discussed, as well as patient selection criteria, and complications. The first prospective study (CaVenT) comparing CDT with anticoagulation alone in acute DVT, despite study shortcomings, corroborates the existing literature indicating improved outcomes with CDT. The potential of the ongoing prospective, multicenter, randomized ATTRACT trial is also highlighted. PMID:28154761

  15. Endovascular Therapy is Effective and Safe for Patients with Severe Ischemic Stroke: Pooled Analysis of IMS III and MR CLEAN Data

    PubMed Central

    Broderick, Joseph P.; Berkhemer, Olvert A.; Palesch, Yuko Y.; Dippel, Diederik W.J.; Foster, Lydia D.; Roos, Yvo B.W.E.M.; van der Lugt, Aad; Tomsick, Thomas A.; Majoie, Charles B.L.M.; van Zwam, Wim H.; Demchuk, Andrew M.; van Oostenbrugge, Robert J.; Khatri, Pooja; Lingsma, Hester F.; Hill, Michael D.; Roozenbeek, Bob; Jauch, Edward C.; Jovin, Tudor G.; Yan, Bernard; von Kummer, Rüdiger; Molina, Carlos A.; Goyal, Mayank; Schonewille, Wouter J.; Mazighi, Mikael; Engelter, Stefan T.; Anderson, Craig S.; Spilker, Judith; Carrozzella, Janice; Ryckborst, Karla J.; Janis, L. Scott; Simpson, Kit

    2015-01-01

    Background and Purpose We assessed the effect of endovascular treatment in acute ischemic stroke patients with severe neurological deficit (NIHSS ≥20) following a pre-specified analysis plan. Methods The pooled analysis of the IMS III and MR CLEAN trial included participants with an NIHSS ≥20 prior to intravenous (IV) t-PA treatment (IMS III) or randomization (MR CLEAN) who were treated with IV t-PA ≤ 3 hours of stroke onset. Our hypothesis was that participants with severe stroke randomized to endovascular therapy following IV t-PA would have improved 90-day outcome (distribution of modified Rankin scale [mRS] scores), as compared to those who received IV t-PA alone. Results Among 342 participants in the pooled analysis (194 from IMS III, 148 from MR CLEAN), an ordinal logistic regression model showed that the endovascular group had superior 90-day outcome compared to the IV t-PA group (adjusted odds ratio [aOR] 1.78; 95% confidence interval [CI] 1.20-2.66). In the logistic regression model of the dichotomous outcome (mRS 0-2, or ‘functional independence’), the endovascular group had superior outcomes (aOR 1.97; 95% CI 1.09-3.56). Functional independence (mRS ≤2) at 90 days was 25% in the endovascular group as compared to 14% in the IV t-PA group. Conclusions Endovascular therapy following IV t-PA within 3 hours of symptom onset improves functional outcome at 90 days after severe ischemic stroke. PMID:26486865

  16. A systematic review and meta-analysis of randomized controlled trials of endovascular thrombectomy compared with best medical treatment for acute ischemic stroke.

    PubMed

    Balami, Joyce S; Sutherland, Brad A; Edmunds, Laurel D; Grunwald, Iris Q; Neuhaus, Ain A; Hadley, Gina; Karbalai, Hasneen; Metcalf, Kneale A; DeLuca, Gabriele C; Buchan, Alastair M

    2015-12-01

    Acute ischemic strokes involving occlusion of large vessels usually recanalize poorly following treatment with intravenous thrombolysis. Recent studies have shown higher recanalization and higher good outcome rates with endovascular therapy compared with best medical management alone. A systematic review and meta-analysis investigating the benefits of all randomized controlled trials of endovascular thrombectomy where at least 25% of patients were treated with a thrombectomy device for the treatment of acute ischemic stroke compared with best medical treatment have yet to be performed. To perform a systematic review and a meta-analysis evaluating the effectiveness of endovascular thrombectomy compared with best medical care for treatment of acute ischemic stroke. Our search identified 437 publications, from which eight studies (totaling 2423 patients) matched the inclusion criteria. Overall, endovascular thrombectomy was associated with improved functional outcomes (modified Rankin Scale 0-2) [odds ratio 1·56 (1·32-1·85), P < 0·00001]. There was a tendency toward decreased mortality [odds ratio 0·84 (0·67-1·05), P = 0·12], and symptomatic intracerebral hemorrhage was not increased [odds ratio 1·03 (0·71-1·49), P = 0·88] compared with best medical management alone. The odds ratio for a favorable functional outcome increased to 2·23 (1·77-2·81, P < 0·00001) when newer generation thrombectomy devices were used in greater than 50% of the cases in each trial. There is clear evidence for improvement in functional independence with endovascular thrombectomy compared with standard medical care, suggesting that endovascular thrombectomy should be considered the standard effective treatment alongside thombolysis in eligible patients. © 2015 The Authors. International Journal of Stroke published by John Wiley & Sons Ltd on behalf of World Stroke Organization.

  17. Basic endovascular skills for trauma course: bridging the gap between endovascular techniques and the acute care surgeon.

    PubMed

    Brenner, Megan; Hoehn, Melanie; Pasley, Jason; Dubose, Joseph; Stein, Deborah; Scalea, Thomas

    2014-08-01

    The use of catheter-based skills is increasing in the field of vascular trauma. Virtual reality simulation (VRS) is a well-established means of endovascular skills training, and potentially lifesaving skills such as resuscitative endovascular balloon occlusion of the aorta (REBOA) may be obtained through VRS. Thirteen faculty members in the Division of Trauma and Critical Care performed REBOA six times on the Vascular Intervention System Training Simulator-C after a didactic and instructional session. Subjects were excluded if they had taken a similar endovascular training course, had additional training in endovascular surgery, or had performed this procedure in the clinical setting. Performance metrics included procedural time; accurate placement of guide wire, sheath, and balloon; correct sequence of steps; economy of motion; and safe use of endovascular tools. A precourse and postcourse test and questionnaire were performed by each subject. Significant improvements in knowledge (p = 0.0013) and procedural task times (p < 0.0001) were observed at the completion of the course. No correlation was observed with endovascular experience in residency, number of central and arterial catheters placed weekly, or other parameters. All trainees strongly agreed that the course was beneficial, and the majority would recommend this training to other acute care surgeons. Damage control endovascular procedures can be effectively taught using VRS. Significant improvements in procedural time and knowledge can be achieved regardless of endovascular experience in residency, years since residency, or other parameters. Novice interventionalists (acute care surgeons) can add a specific skill set (REBOA) to their existing core competencies, which has the potential to improve the survival and/or outcomes of severely injured patients.

  18. Modified SEAGULL

    NASA Technical Reports Server (NTRS)

    Salas, M. D.; Kuehn, M. S.

    1994-01-01

    Original version of program incorporated into program SRGULL (LEW-15093) for use on National Aero-Space Plane project, its duty being to model forebody, inlet, and nozzle portions of vehicle. However, real-gas chemistry effects in hypersonic flow fields limited accuracy of that version, because it assumed perfect-gas properties. As a result, SEAGULL modified according to real-gas equilibrium-chemistry methodology. This program analyzes two-dimensional, hypersonic flows of real gases. Modified version of SEAGULL maintains as much of original program as possible, and retains ability to execute original perfect-gas version.

  19. Determination of sulfite by pervaporation-flow injection with amperometric detection using copper hexacyanoferrate-carbon nanotube modified carbon paste electrode.

    PubMed

    Alamo, Lori Shayne T; Tangkuaram, Tanin; Satienperakul, Sakchai

    2010-06-15

    A pervaporation-flow injection (PFI) method was developed for the determination of sulfite in selected food samples using a copper hexacyanoferrate-carbon nanotube (CuHCF-CNT)-modified carbon paste electrode. The electrochemical behavior of the modified electrode was observed using cyclic voltammetry in comparison to a CuHCF-modified carbon paste electrode and a bare carbon paste electrode at a scan rate of 100mVs(-1) in 0.10M KNO(3). The bare carbon paste electrode gave the lowest response to sulfite, while the presence of CuHCF made the detection of sulfite possible through electrocatalytic oxidation by the hexacyanoferrate in the modified electrodes. The presence of CNT in the CuHCF-CNT-modified sensor gave the most remarkable current for the detection of sulfite and was then used as a working electrode in the amperometric flow-through cell in the pervaporation flow injection system. The PFI method involves the injection of a standard or sample sulfite solution into a sulfuric acid donor stream to generate sulfur dioxide gas and evaporate into the headspace of the pervaporation unit. The sulfur dioxide diffuses through the PTFE hydrophobic membrane into a potassium nitrate acceptor stream and reverts to the sulfite form, which, subsequently, is transported to the electrochemical flow cell where it is analyzed amperometrically at a CuHCF-CNT-modified electrode at +0.55V (vs. Ag/AgCl). The detection was determined to be applicable in the sulfite concentration range of 0.5-50mgL(-1). The sensitivity, detection limit, and sample throughput were determined to be 2.105nALmg(-1), 0.40mgL(-1) and 11h(-1), respectively. The developed PFI method, coupled with the CuHCF-CNT-modified carbon paste electrode, was applied in the determination of sulfite content in sulfite-containing food products. The results agreed well with those obtained through the officially recommended differential pulse polarographic method.

  20. A three-dimensional ground-water-flow model modified to reduce computer-memory requirements and better simulate confining-bed and aquifer pinchouts

    USGS Publications Warehouse

    Leahy, P.P.

    1982-01-01

    The Trescott computer program for modeling groundwater flow in three dimensions has been modified to (1) treat aquifer and confining bed pinchouts more realistically and (2) reduce the computer memory requirements needed for the input data. Using the original program, simulation of aquifer systems with nonrectangular external boundaries may result in a large number of nodes that are not involved in the numerical solution of the problem, but require computer storage. (USGS)

  1. Adapting the Lagrangian speckle model estimator for endovascular elastography: Theory and validation with simulated radio-frequency data

    NASA Astrophysics Data System (ADS)

    Maurice, Roch L.; Ohayon, Jacques; Finet, Gérard; Cloutier, Guy

    2004-08-01

    Intravascular ultrasound (IVUS) is known to be the reference tool for preoperative vessel lesion assessments and for endovascular therapy planning. Nevertheless, IVUS echograms only provide subjective information about vessel wall lesions. Since changes in the vascular tissue stiffness are characteristic of vessel pathologies, catheter-based endovascular ultrasound elastography (EVE) has been proposed in the literature as a method for outlining the elastic properties of vessel walls. In this paper, the Lagrangian Speckle Model Estimator (LSME) is formulated for investigations in EVE, i.e., using a polar coordinate system. The method was implemented through an adapted version of the Levenberg-Marquardt minimization algorithm, using the optical flow equations to compute the Jacobbian matrix. The theoretical framework was validated with simulated ultrasound rf data of mechanically complex vessel wall pathologies. The results, corroborated with Ansys finite element software, demonstrated the potential of EVE to provide useful information about the heterogeneous nature of atherosclerotic plaques.

  2. Adapting the Lagrangian speckle model estimator for endovascular elastography: theory and validation with simulated radio-frequency data.

    PubMed

    Maurice, Roch L; Ohayon, Jacques; Finet, Gérard; Cloutier, Guy

    2004-08-01

    Intravascular ultrasound (IVUS) is known to be the reference tool for preoperative vessel lesion assessments and for endovascular therapy planning. Nevertheless, IVUS echograms only provide subjective information about vessel wall lesions. Since changes in the vascular tissue stiffness are characteristic of vessel pathologies, catheter-based endovascular ultrasound elastography (EVE) has been proposed in the literature as a method for outlining the elastic properties of vessel walls. In this paper, the Lagrangian Speckle Model Estimator (LSME) is formulated for investigations in EVE, i.e., using a polar coordinate system. The method was implemented through an adapted version of the Levenberg-Marquardt minimization algorithm, using the optical flow equations to compute the Jacobbian matrix. The theoretical framework was validated with simulated ultrasound rf data of mechanically complex vessel wall pathologies. The results, corroborated with Ansys finite element software, demonstrated the potential of EVE to provide useful information about the heterogeneous nature of atherosclerotic plaques.

  3. r-modified Crank-Nicholson difference schemes for one dimensional nonlinear viscous Burgers' equation for an incompressible flow

    NASA Astrophysics Data System (ADS)

    Ashyralyev, Allaberen; Gambo, Yusuf Ya'u.

    2016-08-01

    The nonlocal boundary value problem for viscous Burgers' equation is considered. Solutions to the 1-D equation are presented numerically by Rothe, Crank-Nicholson and r-modified Crank-Nicholson difference schemes. Matlab codes for all the three schemes are designed based on the idea of fixed-point iteration procedure and modified Gauss elimination method. The numerical results are compared.

  4. Cost-effective flow injection amperometric system with metal nanoparticle loaded carbon nanotube modified screen printed carbon electrode for sensitive determination of hydrogen peroxide.

    PubMed

    Reanpang, Preeyaporn; Themsirimongkon, Suwaphid; Saipanya, Surin; Chailapakul, Orawon; Jakmunee, Jaroon

    2015-11-01

    Various metal nanoparticles (NPs) decorated on carbon nanotube (CNT) was modified on the home-made screen printed carbon electrode (SPCE) in order to enhances sensitivity of hydrogen peroxide (H2O2) determination. The simple casting method was used for the electrode modification. The monometallic and bimetallic NPs modified electrodes were investigated for their electrochemical properties for H2O2 reduction. The Pd-CNT/SPCE is appropriated to measure the H2O2 reduction at a potential of -0.3 V, then this modified electrode was incorporated with a home-made flow through cell and applied in a simple flow injection amperometry (FI-Amp). Some parameters influencing the resulted modified electrode and the FI-Amp system were studied. The proposed detection system was able to detect H2O2 in the range of 0.1-1.0 mM, with detection limit of 20 µM. Relative standard deviation for 100 replicated injections of 0.6 mM H2O2 was 2.3%. The reproducibility of 6 electrodes preparing in 3 different lots was 8.2%. It was demonstrated for determination of H2O2 in disinfectant, hair colorant and milk samples. Recoveries in the range of 90-109% were observed. The developed system provided high stability, good repeatability, high sample throughput and low reagent consumption. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Modified Taylor-Couette Flow in Multiply-Waisted Hourglass Geometries Simulations based upon Reaction-Diffusion Models

    NASA Astrophysics Data System (ADS)

    Olsen, Thomas; Hou, Yu; Kowalski, Adam; Wiener, Richard

    2006-05-01

    The Reaction-Diffusion model predicted a period doubling cascade to chaos in a situation analagous Taylor- Couette flow with hourglass geometry. This cascade to chaos was discovered in the actual fluid flow experiments. We model Taylor-Couette flow in a cylindrical geometry with multiple waists of super-critical flow connected by regions of barely super-critical flow by corresponding Reaction-Diffusion models. We compare our results to the findings of an ongoing experimental program. H. Riecke and H.-G. Paap, Europhys. Lett. 14, 1235 (1991). Richard J. Wiener et al, Phys. Rev. E 55, 5489 (1997).

  6. Risk Score for Neurological Complications After Endovascular Treatment of Unruptured Intracranial Aneurysms

    PubMed Central

    Ji, Wenjun; Liu, Aihua; Lv, Xianli; Kang, Huibin; Sun, Liqian; Li, Youxiang; Yang, Xinjian; Jiang, Chuhan

    2016-01-01

    Background and Purpose— Procedure-related neurological complications are common after endovascular treatment of unruptured intracranial aneurysms. We aimed to develop a score to quantify individual patient risk. Methods— We retrospectively analyzed consecutive patients who underwent endovascular treatment for unruptured intracranial aneurysms between January 2012 and September 2015. After excluding those who lost to follow-up and those with fusiform unruptured intracranial aneurysms, included patients were randomly divided into a derivation group (60%) and a validation group (40%). A neurological complication was defined as any transient or permanent increase in the modified Rankin Scale score after aneurysm embolization. A risk score for neurological complications was derived from multivariable logistic regression analyses in the derivation group and validated in the validation group. Results— Overall, 1060 patients were included (636 in the derivation group and 424 in the validation group). The incidence of neurological complications was 5.5% (95% confidence interval, 3.8%–7.4%). A 3-point risk score (S-C-C) was derived to predict neurological complications (size [≥10 mm=1], core areas [yes=1], and cerebral ischemic comorbidity [yes=1]). The incidence of neurological complications varied from 2.2% in 0-point patients to 25.0% in 3-point patients. The score demonstrated significant discrimination (C-statistic, 0.714; 95% confidence interval, 0.624–0.804) and calibration (McFadden R2, 0.102) in the derivation group. Excellent prediction, discrimination, and calibration properties were reproduced in the validation group. Conclusions— One in 20 patients will develop neurological complications after endovascular treatment of unruptured intracranial aneurysms. The S-C-C score may be useful for predicting these adverse outcomes based on variables in daily practice. PMID:26869386

  7. Effect of endovascular reperfusion in relation to site of arterial occlusion

    PubMed Central

    Hamilton, Scott A.; Liebeskind, David S.; Tomsick, Tom A.; Demchuk, Andrew M.; Nogueira, Raul G.; Marks, Michael P.; Jahan, Reza; Gralla, Jan; Yoo, Albert J.; Yeatts, Sharon D.; Palesch, Yuko Y.; Saver, Jeffrey L.; Pereira, Vitor M.; Broderick, Joseph P.; Albers, Gregory W.; Lansberg, Maarten G.

    2016-01-01

    Objective: To assess whether the association between reperfusion and improved clinical outcomes after stroke differs depending on the site of the arterial occlusive lesion (AOL). Methods: We pooled data from Solitaire With the Intention for Thrombectomy (SWIFT), Solitaire FR Thrombectomy for Acute Revascularisation (STAR), Diffusion and Perfusion Imaging Evaluation for Understanding Stroke Evolution Study 2 (DEFUSE 2), and Interventional Management of Stroke Trial (IMS III) to compare the strength of the associations between reperfusion and clinical outcomes in patients with internal carotid artery (ICA), proximal middle cerebral artery (MCA) (M1), and distal MCA (M2/3/4) occlusions. Results: Among 710 included patients, the site of the AOL was the ICA in 161, the proximal MCA in 389, and the distal MCA in 160 patients (M2 = 131, M3 = 23, and M4 = 6). Reperfusion was associated with an increase in the rate of good functional outcome (modified Rankin Scale [mRS] score 0–2) in patients with ICA (odds ratio [OR] 3.5, 95% confidence interval [CI] 1.7–7.2) and proximal MCA occlusions (OR 6.2, 95% CI 3.8–10.2), but not in patients with distal MCA occlusions (OR 1.4, 95% CI 0.8–2.6). Among patients with M2 occlusions, a subset of the distal MCA cohort, reperfusion was associated with excellent functional outcome (mRS 0–1; OR 2.2, 95% CI 1.0–4.7). Conclusions: The association between endovascular reperfusion and better clinical outcomes is more profound in patients with ICA and proximal MCA occlusions compared to patients with distal MCA occlusions. Because there are limited data from randomized controlled trials on the effect of endovascular therapy in patients with distal MCA occlusions, these results underscore the need for inclusion of this subgroup in future endovascular therapy trials. PMID:26802090

  8. Endovascular Coil Embolization of Segmental Arteries Prevents Paraplegia After Subsequent TAAA Repair – An Experimental Model

    PubMed Central

    Geisbüsch, S; Stefanovic, A; Koruth, JS; Lin, HM; Morgello, S; Weisz, DJ; Griepp, RB; Di Luozzo, G

    2013-01-01

    Objective To test a strategy for minimizing ischemic spinal cord injury (SCI) following extensive thoracoabdominal aneurysm (TAAA) repair, we occluded a small number of segmental arteries (SAs) endovascularly one week before simulated aneurysm repair in an experimental model. Methods 30 juvenile Yorkshire pigs (25.2±1.7kg) were randomized into three groups. All SAs—intercostal and lumbar—were sacrificed by a combination of surgical ligation of the lumbar SAs and occlusion of intercostal SAs with thoracic endovascular stent grafting (TEVAR). 7–10 days before this simulated TAAA replacement, SAs in the lower thoracic/upper lumbar region were occluded using embolization coils: 1.5±0.5 SAs in Group 1 (T13/L1), and 4.5±0.5 in Group 2 (T11-L3). No SAs were coiled in the controls. Hind limb function was evaluated blindly from daily videotapes using a modified Tarlov score: 0=paraplegia; 9=full recovery. After sacrifice, each segment of spinal cord was graded histologically using the 9-point Kleinman score: 0=normal, 8=complete necrosis. Results Hind limb function remained normal after coil embolization. After simulated TAAA repair, paraplegia occurred in 6/10 control pigs, but only 2/10 pigs in Group 1: no pigs in Group 2 had SCI. Tarlov scores were significantly better in Group 2 (Control vs 1 p=0.06; Control vs 2 p= 0.0002; 1 vs 2 p=0.05). A dramatic reduction in histologic damage—most prominently in the coiled region—was seen when SAs were embolized before simulated TAAA repair. Conclusions Endovascular coiling of 2–4 SAs prevents paraplegia in an experimental model of extensive hybrid TAAA repair, and helps protect the spinal cord from ischemic histopathological injury. A clinical trial in a selected patient population at high risk for postoperative SCI may be appropriate. PMID:24220154

  9. Mechanical endovascular thrombectomy for acute ischemic stroke: a retrospective multicenter study in Belgium.

    PubMed

    Fockaert, Niels; Coninckx, Marieke; Heye, Sam; Defreyne, Luc; Brisbois, Denis; Goffette, Pierre; Gralla, Jan; Mordasini, Pasquale; Peeters, Andre; Desfontaines, Philippe; Hemelsoet, Dimitri; Thijs, Vincent; Lemmens, Robin

    2016-03-01

    Clinical trials have shown a beneficial effect of mechanical thrombectomy in acute ischemic stroke patients treated within six up to even 12 h after symptom onset. This treatment was already performed in selected hospitals in Belgium before completion of the randomized controlled trials. Outcome data on these procedures in Belgium have not been published. We performed a retrospective multicenter study of all patients with acute ischemic stroke treated with mechanical endovascular therapy in four hospitals in Belgium. Clinical outcomes, as measured by the modified Rankin Scale (mRS), site of arterial occlusion, reperfusion and the association between these variables were studied. The study included 80 patients: 65 patients with an occlusion in the anterior circulation and 15 with an occlusion in the posterior circulation. Good functional outcome (GFO) rates, defined as mRS 0-2 at 90 days, were 42 % in all patients, 44 % in anterior circulation stroke and 34 % in posterior circulation stroke. Reperfusion was achieved in 78 % of patients; more (100 %) in patients with posterior compared to patients with anterior circulation stroke (72 %; p = 0.02). The rate of GFO was greater in patients with reperfusion versus patients in whom reperfusion was not achieved (adjusted OR 8.2, 95 % CI 2.0-34.2). Symptomatic intracerebral hemorrhage was documented in 5 % of all patients. Endovascular treatment with mechanical devices for acute ischemic stroke in Belgium results in GFO and reperfusion rates similar to recently published results in the endovascular-treated arms of randomized clinical trials. Rates of symptomatic intracranial hemorrhage are low and comparable to other cohort studies and clinical trials.

  10. Endovascular treatment of recurrent intracranial aneurysms following previous microsurgical clipping with the Pipeline Embolization Device.

    PubMed

    Ding, Dale; Starke, Robert M; Evans, Avery J; Jensen, Mary E; Liu, Kenneth C

    2014-07-01

    The treatment of intracranial aneurysms with microsurgical clipping is associated with a very low rate of recurrence. However, in cases of aneurysm recurrence after previous clipping, microsurgical dissection due to adhesions and fibrosis may be challenging, and it may be difficult to safely occlude the recurrent lesion without the risk of significant morbidity. Flow-diverting stents have drastically changed the landscape of endovascular neurosurgery. We present two patients with large, recurrent supraclinoid internal carotid artery (ICA) aneurysms which were previously clipped 17 and 23 years ago at outside institutions. Both recurrent lesions were treated with the Pipeline Embolization Device (PED; ev3 Endovascular, Irvine, CA, USA) without radiographic or clinical complications. In the first patient, the 15 mm aneurysm significantly decreased in size at 6 month angiographic follow-up. The 21 mm aneurysm in the second patient was completely occluded 7 months following PED treatment. The moderate degree of in-stent stenosis present on initial follow-up imaging resolved on angiography 11 months post-treatment. The management of recurrent aneurysms after clipping is sparsely reported in the literature due to its infrequent occurrence. In carefully selected cases, flow-diverting stents may be used for complex aneurysms of the distal ICA, even for those which have recurred following microsurgical clipping.

  11. The stentable in vitro artery: an instrumented platform for endovascular device development and optimization.

    PubMed

    Antoine, Elizabeth E; Cornat, François P; Barakat, Abdul I

    2016-12-01

    Although vascular disease is a leading cause of mortality, in vitro tools for controlled, quantitative studies of vascular biological processes in an environment that reflects physiological complexity remain limited. We developed a novel in vitro artery that exhibits a number of unique features distinguishing it from tissue-engineered or organ-on-a-chip constructs, most notably that it allows deployment of endovascular devices including stents, quantitative real-time tracking of cellular responses and detailed measurement of flow velocity and lumenal shear stress using particle image velocimetry. The wall of the stentable in vitro artery consists of an annular collagen hydrogel containing smooth muscle cells (SMCs) and whose lumenal surface is lined with a monolayer of endothelial cells (ECs). The system has in vivo dimensions and physiological flow conditions and allows automated high-resolution live imaging of both SMCs and ECs. To demonstrate proof-of-concept, we imaged and quantified EC wound healing, SMC motility and altered shear stresses on the endothelium after deployment of a coronary stent. The stentable in vitro artery provides a unique platform suited for a broad array of research applications. Wide-scale adoption of this system promises to enhance our understanding of important biological events affecting endovascular device performance and to reduce dependence on animal studies. © 2016 The Author(s).

  12. 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.

  13. Endovascular Repair of Descending Thoracic Aortic Aneurysm

    PubMed Central

    2005-01-01

    Executive Summary Objective To conduct an assessment on endovascular repair of descending thoracic aortic aneurysm (TAA). Clinical Need Aneurysm is the most common condition of the thoracic aorta requiring surgery. Aortic aneurysm is defined as a localized dilatation of the aorta. Most aneurysms of the thoracic aorta are asymptomatic and incidentally discovered. However, TAA tends to enlarge progressively and compress surrounding structures causing symptoms such as chest or back pain, dysphagia (difficulty swallowing), dyspnea (shortness of breath), cough, stridor (a harsh, high-pitched breath sound), and hoarseness. Significant aortic regurgitation causes symptoms of congestive heart failure. Embolization of the thrombus to the distal arterial circulation may occur and cause related symptoms. The aneurysm may eventually rupture and create a life-threatening condition. The overall incidence rate of TAA is about 10 per 100,000 person-years. The descending aorta is involved in about 30% to 40% of these cases. The prognosis of large untreated TAAs is poor, with a 3-year survival rate as low as 25%. Intervention is strongly recommended for any symptomatic TAA or any TAA that exceeds twice the diameter of a normal aorta or is 6 cm or larger. Open surgical treatment of TAA involves left thoracotomy and aortic graft replacement. Surgical treatment has been found to improve survival when compared with medical therapy. However, despite dramatic advances in surgical techniques for performing such complex operations, operative mortality from centres of excellence are between 8% and 20% for elective cases, and up to 50% in patients requiring emergency operations. In addition, survivors of open surgical repair of TAAs may suffer from severe complications. Postoperative or postprocedural complications of descending TAA repair include paraplegia, myocardial infarction, stroke, respiratory failure, renal failure, and intestinal ischemia. The Technology Endovascular aortic aneurysm

  14. Assessment of the modified rotation/curvature correction SST turbulence model for simulating swirling reacting unsteady flows in a solid-fuel ramjet engine

    NASA Astrophysics Data System (ADS)

    Musa, Omer; Xiong, Chen; Changsheng, Zhou; Lunkun, Gong

    2016-12-01

    The present paper presents an assessment of the performance of the modified curvature-correction shear stress transport turbulence model (SST-CCM) proposed by Omer Musa et al. (2016) [12], for simulating swirling reacting unsteady flow in a solid-fuel ramjet engine. Results are compared to both the original SST and rotation-curvature SST (SST-RC) turbulence models. First, a numerical model has been developed to solve axisymmetric unsteady Reynolds-averaged Navier-Stokes equations of the turbulent swirling compressible flow field with chemical reactions. Second, in order to evaluate the accuracy and robustness of the code, experiment on the solid-fuel ramjet without swirl has been performed and simulation on Shock-induced combustion benchmark case is carried out as well. Finally, unsteady simulations are carried out for reacting turbulent flows in a solid-fuel ramjet using Polyethylene (PE) solid fuel with three different turbulence models. It is found that in terms of accuracy for simulating reacting swirling flows the modified model slightly improves the original SST model and is quite similar to the SST-RC.

  15. Wind-tunnel investigation of aerodynamic characteristics and wing pressure distributions of an airplane with variable-sweep wings modified for laminar flow

    NASA Technical Reports Server (NTRS)

    Hallissy, James B.; Phillips, Pamela S.

    1989-01-01

    A wind tunnel test was conducted to evaluate the aerodynamic characteristics and wing pressure distributions of a variable wing sweep aircraft having wing panels that are modified to promote laminar flow. The modified wing section shapes were incorporated over most of the exposed outer wing panel span and were obtained by extending the leading edge and adding thickness to the existing wing upper surface forward of 60 percent chord. Two different wing configurations, one each for Mach numbers 0.7 and 0.8, were tested on the model simultaneously, with one wing configuration on the left side and the other on the right. The tests were conducted at Mach numbers 0.20 to 0.90 for wing sweep angles of 20, 25, 30, and 35 degrees. Longitudinal, lateral and directional aerodynamic characteristics of the modified and baseline configurations, and selected pressure distributions for the modified configurations, are presented in graphical form without analysis. A tabulation of the pressure data for the modified configuration is available as microfiche.

  16. Viscous dissipation effects on MHD slip flow and heat transfer in porous micro duct with LTNE assumptions using modified lattice Boltzmann method

    NASA Astrophysics Data System (ADS)

    Rabhi, R.; Amami, B.; Dhahri, H.; Mhimid, A.

    2017-06-01

    This paper deals with heat transfer and fluid flow in a porous micro duct under local thermal non equilibrium conditions subjected to an external oriented magnetic field. The considered sample is a micro duct filled with porous media assumed to be homogenous, isotropic and saturated. The slip velocity and the temperature jump were uniformly imposed to the wall. In modeling the flow, the Brinkmann-Forchheimer extended Darcy model was incorporated into the momentum equations. In the energy equation, the local thermal non equilibrium between the two phases was adopted. A modified axisymmetric lattice Boltzmann method was used to solve the obtained governing equation system. Attention was focused on the influence of the emerging parameters such as Knudsen number, Kn, Hartmann number, Ha, Eckert number, Ec, Biot number, Bi and the magnetic field inclination γ on flow and heat transfer throughout this paper.

  17. Analytic study of developing flows in a tube laden with non-evaporating and evaporating drops via a modified linearization of the two-phase momentum equations

    NASA Astrophysics Data System (ADS)

    Khosid, S.; Tambour, Y.

    A novel modification of the classical Langhaar linearization of the mutually coupled momentum equations for developing two-phase flows in circular ducts is presented. This modification enables us to treat: (i) flows developing from spatially periodic initial velocity distributions without the presence of droplets, and (ii) two-phase flows in which monosize, non-evaporating and evaporating droplets suspended in a developing gas flow of an initially uniform velocity distribution exchange momentum with the host-gas flow. New solutions are presented for the downstream evolution in the velocity profiles which develop from spatially periodic initial velocity distributions that eventually reach the fully developed Poiseuille velocity profile. These solutions are validated by employing known numerical procedures, providing strong support for the physical underpinnings of the present modified linearization. New solutions are also presented for the evolution in drop velocities and vapour spatial distributions for evaporating droplets suspended in an initially uniform velocity profile of the host gas. Asymptotic solutions are presented for the flow region which lies very close to the inlet of the tube, where the relative velocity between the droplets and the host gas is high, and thus the velocity fields of the two phases are mutually coupled. These solutions provide new explicit formulae for the droplet velocity field as a function of the initial conditions and droplet diameter (relative to the tube diameter) for non-evaporating drops, and also as a function of evaporation rate for evaporating drops.

  18. Early Experiences of Sandwich Technique to Preserve Pelvic Circulation during Endovascular Aneurysm Repair.

    PubMed

    Kim, Daehwan; Chung, Jung Kee; Park, Hyung Sub; Jung, In Mok; Lee, Taeseung

    2017-06-01

    To report experiences of the sandwich technique (ST) for preservation of pelvic flow during endovascular repair of complex aortic or aortoiliac aneurysms. Eight patients underwent elective endovascular aneurysm repair (EVAR) using the ST between March 2013 and February 2017. The anatomic indications for the ST were complex aortoiliac aneurysms (5 cases), abdominal aortic aneurysms (AAA) with non-diseased short common iliac arteries (2 cases) and AAA with unilateral occluded iliac artery (1 case). The ST was performed through both femoral and brachial approach. Patient clinical and radiologic data were collected and analyzed. Eight patients (7 male; mean age, 73.4 years) were followed over a mean period of 277 days (range, 9-1,106 days). The technical success rate was 100%. The primary patency rate of the iliac stent-grafts was 88% (14/16 cases). One internal iliac and 1 external iliac stent-graft occlusion was observed during the early postoperative period. There was 1 gutter endoleak which disappeared spontaneously within 4 days, and there were 2 type II endoleaks: one treated by coil embolization after 13 months, and the other observed without treatment. There were no cases of sac growth or aneurysm-related deaths, and no cases of buttock claudication or impotence. The ST is a safe and feasible technique to preserve pelvic circulation during endovascular treatment of complex aortoiliac aneurysms. The need to expand the indications for complex EVARs with adjunctive procedures, such as the ST is highlighted in situations where branched/fenestrated device availability is limited.

  19. Application of endovascular coiling and subsequent Onyx 34 embolization in anterior communicating artery aneurysms with adjacent hematoma.

    PubMed

    Fang, Yi-Bin; Li, Qiang; Yang, Peng-Fei; Zhang, Qi; Wu, Yi-Na; Feng, Zheng-Zhe; Huang, Qing-Hai; Xu, Yi; Liu, Jian-Min

    2014-08-01

    Small anterior communicating artery aneurysms with recurrent bleeding and adjacent hematoma may have a high risk of post-operative rebleeding. This clinical study summarizes our preliminary experience with this subset of aneurysms, which were treated with endovascular coiling and subsequent Onyx 34 embolization. We retrospectively reviewed the data of 9 patients suffering from small anterior communicating artery aneurysms treated with the combination of coils and Onyx. The clinical characteristics, angiographic outcomes, and follow-up results are reviewed. Endovascular coiling and Onyx embolization were successfully accomplished in all 9 cases. The Raymond scale ratings of the treatments are all class I with the parent arteries kept patent. One patient died of severe brain edema on the 5th post-operative day. The modified Rankin scale (mRS) score for the other 8 patients at follow-ups (6m to 26m, 15.8m on average) was 0 in 5 cases, 1 in 2 cases, and 3 in 1 case. Seven of 8 patients (87.5%) underwent angiographic follow-up that demonstrated persistent durable occlusion with no recanalization. Endovascular coiling and subsequent Onyx 34 embolization may be effective in treating anterior communicating artery aneurysms with adjacent hematoma. Further studies with larger sample size and adequate follow-up are required to verify its safety and efficacy as well as to evaluate the long-term outcome. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Clinical Outcome of Paraclinoid Internal Carotid Artery Aneurysms After Microsurgical Neck Clipping in Comparison with Endovascular Embolization

    PubMed Central

    Bae, Dong-Hyun; Won, Yu-Deok; Choi, Kyu-Sun; Cheong, Jin-Hwan; Yi, Hyeong-Joong; Kim, Choong-Hyun

    2014-01-01

    Objective Because of the complex anatomical association among vascular, dural, and bony structures, paraclinoid internal carotid artery (ICA) aneurysms remain a major challenge for vascular neurosurgeons. We studied the clinical outcomes of 61 paraclinoid ICA aneurysms after microsurgical clipping in comparison with endovascular coiling. Materials and Methods Between January 2008 and December 2012, we treated 61 paraclinoid ICA aneurysms created by surgical clipping or endovascular coiling. Preoperative neurologic status and postoperative outcome were evaluated using the Glasgow coma scale (GCS) and the modified Rankin scale (mRS). Postoperative hydrocephalus and vasospasm were reviewed using the patients' medical charts. Results Most patients were in good clinical condition before the operations and had good treatment outcomes. Clinical vasospasm was observed after the operation in five patients, and hydrocephalus occurred in six patients. No statistically significant difference regarding aneurysm size, sex, GCS score, H-H grade, and mRS was observed between the surgical clipping group and the endovascular coiling group. In addition, the treatment results and complications did not show statistically significant difference in either group. Conclusion Surgical occlusion of paraclinoid ICA aneurysms is difficult; however, no significant differences were observed in the treatment results or complications when compared with coil embolization. In particular, use of an adequate surgical technique may lead to better outcomes than those for coil embolization in the treatment of large and/or wide-neck paraclinoid ICA aneurysms. PMID:25340024

  1. Endovascular Treatment of Dural Arteriovenous Fistulas: Single Center Experience

    PubMed Central

    Oh, Jae-Sang; Oh, Hyuk-Jin; Shim, Jai-Joon; Bae, Hack-Gun; Lee, Kyeong-Seok

    2016-01-01

    Objective Treatment of intracranial dural arteriovenous fistulas (dAVFs) remains a challenge. However, after introduction of Onyx, transarterial approach is the preferred treatment option in many centers. We report our experience of dAVFs embolization with special emphasis on transarterial approach. Methods Seventeen embolization procedures were performed in 13 patients with dAVFs between Jan 2009 and Oct 2014. Clinical symptoms, location and type of fistulas, embolization methods, complications, radiological and clinical outcomes were evaluated using charts and PACS images. Results All 13 patients had symptomatic lesions. The locations of fistulas were transverse-sigmoid sinus in 6, middle fossa dura in 4, cavernous sinus in 2, and superior sagittal sinus in 1 patient. Cognard types were as follows : I in 4, IIa in 2, IIa+IIb in 5, and IV in 2. Embolization procedures were performed ≥2 times in 3 patients. Nine patients were treated with transarterial Onyx embolization alone. One of these required direct surgical puncture of middle meningeal artery. Complete obliteration of fistulas was achieved in 11/13 (85%) patients. There were no complications except for 1 case of Onyx migration in cavernous dAVF. Modified Rankin scale score at post-operative 3 months were 0 in 11, and 3 in 2 patients. Conclusion Transarterial Onyx embolization can be a first line therapeutic option in patients with dAVFs. However, transvenous approach should be tried first in cavernous sinus dAVF because of the risk of intracranial migration of liquid embolic materials. Furthermore, combined surgical endovascular approach can be considered as a useful option in inaccessible route. PMID:26885282

  2. Lesion location, stability, and pretreatment management: factors affecting outcomes of endovascular treatment for vertebrobasilar atherosclerosis.

    PubMed

    Alexander, Matthew D; Rebhun, Jeffrey M; Hetts, Steven W; Kim, Anthony S; Nelson, Jeffrey; Kim, Helen; Amans, Matthew R; Settecase, Fabio; Dowd, Christopher F; Halbach, Van V; Higashida, Randall T; Cooke, Daniel L

    2016-05-01

    The proper role of endovascular treatment of cervicocerebral atherosclerosis is unclear. Posterior circulation disease has not been investigated as extensively as disease in the anterior circulation. In this study, we characterized the rates of technical success, transient ischemic attack, stroke, and death or disability, for both acute and elective endovascular treatment of atherosclerosis in the vertebrobasilar system. We identified patients with atherosclerosis of the vertebrobasilar circulation who underwent endovascular intervention at our hospital through retrospective medical record review, and evaluated the association between lesion and treatment features and subsequent stroke, death, or disability at 30 days and 1 year. We identified 136 lesions in 122 patients, including 13 interventions for acute strokes. Technical success was achieved in 123 of 136 cases (90.4%). Elective procedures had higher rates of technical success (6.5% vs 15.4%, p=0.21) and better clinical outcomes. In multivariate analysis, intracranial lesions were associated with more disability (modified Rankin Scale score >2) at 30 days (OR 7.1, p=0.01) and 1 year (OR 10, p=0.03). Patients with non-hypoperfusion related symptoms had fewer strokes at follow-up at 1 year when treated after an asymptomatic interval of >10 days compared with those treated within 10 days of the presenting symptoms (OR 0.2, p=0.03). Statin treatment prior to intervention was associated with favorable outcomes across several examined endpoints. Preoperative antiplatelet treatment was associated with lower rates of disability at 30 days and 1 year (OR 0.1, p<0.01 and OR 0.07, p=0.01, respectively), and preoperative anticoagulation treatment was associated with higher rates of death at 30 days, particularly when prescribed for reasons other than atrial fibrillation (OR 6.4, p=0.01). Endovascular treatment of symptomatic vertebrobasilar atherosclerosis can be performed safely and with good

  3. Clinical applications of robotic technology in vascular and endovascular surgery.

    PubMed

    Antoniou, George A; Riga, Celia V; Mayer, Erik K; Cheshire, Nicholas J W; Bicknell, Colin D

    2011-02-01

    Emerging robotic technologies are increasingly being used by surgical disciplines to facilitate and improve performance of minimally invasive surgery. Robot-assisted intervention has recently been introduced into the field of vascular surgery to potentially enhance laparoscopic vascular and endovascular capabilities. The objective of this study was to review the current status of clinical robotic applications in vascular surgery. A systematic literature search was performed in order to identify all published clinical studies related to robotic implementation in vascular intervention. Web-based search engines were searched using the keywords "surgical robotics," "robotic surgery," "robotics," "computer assisted surgery," and "vascular surgery" or "endovascular" for articles published between January 1990 and November 2009. An evaluation and critical overview of these studies is reported. In addition, an analysis and discussion of supporting evidence for robotic computer-enhanced telemanipulation systems in relation to their applications in laparoscopic vascular and endovascular surgery was undertaken. Seventeen articles reporting on clinical applications of robotics in laparoscopic vascular and endovascular surgery were detected. They were either case reports or retrospective patient series and prospective studies reporting laparoscopic vascular and endovascular treatments for patients using robotic technology. Minimal comparative clinical evidence to evaluate the advantages of robot-assisted vascular procedures was identified. Robot-assisted laparoscopic aortic procedures have been reported by several studies with satisfactory results. Furthermore, the use of robotic technology as a sole modality for abdominal aortic aneurysm repair and expansion of its applications to splenic and renal artery aneurysm reconstruction have been described. Robotically steerable endovascular catheter systems have potential advantages over conventional catheterization systems

  4. Laser-induced (endo)vascular photothermal effects studied by combined brightfield and fluorescence microscopy in hamster dorsal skin fold venules

    NASA Astrophysics Data System (ADS)

    Bezemer, R.; Heger, M.; van den Wijngaard, J. P. H.; Mordon, S. R.; van Gemert, M. J. C.; Beek, J. F.

    2007-07-01

    The putative features of the (endo)vascular photothermal response, characterized by laser-induced thermal denaturation of blood and vessel wall constituents, have been elucidated individually, but not simultaneously in dynamic, isolated in vivo systems. A hamster dorsal skin fold model in combination with brightfield/fluorescence intravital microscopy was used to examine the effect of laser pulse duration and blood flow velocity on the size of the thermal coagulum, its attachment behavior, and laser-mediated vasomotion. The size of the coagulum and the extent of vasoconstriction and latent vasodilation were proportional to the laser pulse duration, but pulse duration had no effect on coagulum attachment/dislodgement. Blood flow velocity exhibited no significant effect on the studied parameters. The (endo)vascular photothermal response is governed predominantly by laser energy deposition and to a marginal extent by blood flow velocity.

  5. Relevance of blood-brain barrier disruption after endovascular treatment of ischemic stroke: dual-energy computed tomographic study.

    PubMed

    Renú, Arturo; Amaro, Sergio; Laredo, Carlos; Román, Luis San; Llull, Laura; Lopez, Antonio; Urra, Xabier; Blasco, Jordi; Oleaga, Laura; Chamorro, Ángel

    2015-03-01

    Computed tomographic (CT) high attenuation (HA) areas after endovascular therapy for acute ischemic stroke are a common finding indicative of blood-brain barrier disruption. Dual-energy CT allows an accurate differentiation between HA areas related to contrast staining (CS) or to brain hemorrhage (BH). We sought to evaluate the prognostic significance of the presence of CS and BH after endovascular therapy. A prospective cohort of 132 patients treated with endovascular therapy was analyzed. According to dual-energy CT findings, patients were classified into 3 groups: no HA areas (n=53), CS (n=32), and BH (n=47). The rate of new hemorrhagic transformations was recorded at follow-up neuroimaging. Clinical outcome was evaluated at 90 days with the modified Rankin Scale (poor outcome, 3-6). Poor outcome was associated with the presence of CS (odds ratio [OR], 11.3; 95% confidence interval, 3.34-38.95) and BH (OR, 10.4; 95% confidence interval, 3.42-31.68). The rate of poor outcome despite complete recanalization was also significantly higher in CS (OR, 9.7; 95% confidence interval, 2.55-37.18) and BH (OR, 15.1; 95% confidence interval, 3.85-59.35) groups, compared with the no-HA group. Patients with CS disclosed a higher incidence of delayed hemorrhagic transformation at follow-up (OR, 4.5; 95% confidence interval, 1.22-16.37) compared with no-HA patients. Blood-brain barrier disruption, defined as CS and BH on dual-energy CT, was associated with poor clinical outcomes in patients with stroke treated with endovascular therapies. Moreover, isolated CS was associated with delayed hemorrhagic transformation. These results support the clinical relevance of blood-brain barrier disruption in acute stroke. © 2015 American Heart Association, Inc.

  6. Magnetic resonance imaging-based endovascular versus medical stroke treatment for symptom onset up to 12 h.

    PubMed

    Wouters, Anke; Lemmens, Robin; Christensen, Soren; Wilms, Guido; Dupont, Patrick; Mlynash, Michael; Schneider, Armin; Laage, Rico; Cereda, Carlo W; Lansberg, Maarten G; Albers, Gregory W; Thijs, Vincent

    2016-01-01

    Recent trials have shown a clear benefit of endovascular therapy for stroke patients presenting within 6 h after stroke onset. Imaging-based selection may identify a cohort with a favorable response to endovascular therapy, in an even later time window. We performed an indirect comparison between outcomes seen in DEFUSE 2, a prospective cohort study of patients who received a baseline MRI before endovascular therapy, and a control group from AXIS 2 receiving standard medical care up to 12 h after symptom onset. Patients from AXIS 2 with a confirmed large vessel occlusion were selected as a control group for DEFUSE 2-patients. The primary endpoint was good functional outcome at day 90 (Modified Rankin Score 0-2). We performed a stratified analysis based on the presence of the target mismatch for both studies and reperfusion status in DEFUSE 2. We compared good functional outcome in 108 patients from AXIS 2 and 99 patients from DEFUSE 2. In DEFUSE 2-patients with the target mismatch profile in whom reperfusion was achieved, the rate of good functional outcome was increased compared to target mismatch patients in AXIS 2, 54% versus 29% (OR 3.2, 95% CI 1.1-9.4). In target mismatch patients treated between 6 and 12 h after stroke onset, this association between study and good functional outcome remained present (OR 9.0, 95% CI 1.1-75.8). This indirect comparison suggests that endovascular treatment resulting in substantial reperfusion is associated with improved outcome in target mismatch patients even beyond 6 h after stroke onset. Confirmation is needed from future clinical trials that randomize patients beyond the 6 h time window. © 2016 World Stroke Organization.

  7. Have Endovascular Procedures Negatively Impacted General Surgery Training?

    PubMed Central

    Grabo, Daniel J.; DiMuzio, Paul J.; Kairys, John C.; McIlhenny, Stephen E.; Crawford, Albert G.; Yeo, Charles J.

    2007-01-01

    Objective: Technological advances in vascular surgery have changed the field dramatically over the past 10 years. Herein, we evaluate the impact of endovascular procedures on general surgery training. Methods: National operative data from the Residency Review Committee for Surgery were examined from 1997 through 2006. Total major vascular operations, traditional open vascular operations and endovascular procedures were evaluated for mean number of cases per graduating chief general surgery resident (GSR) and vascular surgery fellow (VSF). Results: As endovascular surgical therapies became widespread, GSR vascular case volume decreased 34% over 10 years, but VSF total cases increased 78%. GSR experience in open vascular operations decreased significantly, as evidenced by a 52% decrease (P < 0.0001) in elective open AAA repair. VSFs have also seen significant decreases in open vascular procedures. Experience in endovascular procedures has increased for both general surgery and vascular residents, but the increase has been much larger in absolute number for VSFs. Conclusions: GSR experience in open vascular procedures has significantly decreased as technology has advanced within the field. Unlike VSFs, this loss has not been replaced by direct experience with endovascular training. These data demonstrate the impact technology can have on how we currently train general surgeons. New educational paradigms may be necessary in which either vascular surgery as an essential component is abandoned or training in catheter-based interventions becomes required. PMID:17717451

  8. Total Endovascular Aortic Repair in a Patient with Marfan Syndrome.

    PubMed

    Amako, Mau; Spear, Rafaëlle; Clough, Rachel E; Hertault, Adrien; Azzaoui, Richard; Martin-Gonzalez, Teresa; Sobocinski, Jonathan; Haulon, Stéphan

    2017-02-01

    The aim of this study is to describe a total endovascular aortic repair with branched and fenestrated endografts in a young patient with Marfan syndrome and a chronic aortic dissection. Open surgery is the gold standard to treat aortic dissections in patients with aortic disease and Marfan syndrome. In 2000, a 38-year-old man with Marfan syndrome underwent open ascending aorta repair for an acute type A aortic dissection. One year later, a redo sternotomy was performed for aortic valve replacement. In 2013, the patient presented with endocarditis and pulmonary infection, which necessitated tracheostomy and temporary dialysis. In 2014, the first stage of the endovascular repair was performed using an inner branched endograft to exclude a 77-mm distal arch and descending thoracic aortic aneurysm. In 2015, a 63-mm thoracoabdominal aortic aneurysm was excluded by implantation of a 4-fenestrated endograft. Follow-up after both endovascular repairs was uneventful. Total aortic endovascular repair was successfully performed to treat a patient with arch and thoraco-abdominal aortic aneurysm associated with chronic aortic dissection and Marfan syndrome. The postoperative images confirmed patency of the endograft and its branches, and complete exclusion of the aortic false lumen. Endovascular repair is a treatment option in patients with connective tissue disease who are not candidates for open surgery. Long-term follow-up is required to confirm these favorable early outcomes. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. National Institutes of Health Stroke Scale-Time Score Predicts Outcome after Endovascular Therapy in Acute Ischemic Stroke: A Retrospective Single-Center Study.

    PubMed

    Todo, Kenichi; Sakai, Nobuyuki; Kono, Tomoyuki; Hoshi, Taku; Imamura, Hirotoshi; Adachi, Hidemitsu; Kohara, Nobuo

    2016-05-01

    Outcomes after successful endovascular therapy in acute ischemic stroke are associated with onset-to-reperfusion time (ORT) and the National Institutes of Health Stroke Scale (NIHSS) score. In intravenous recombinant tissue plasminogen activator therapy, the NIHSS-time score, calculated by multiplying onset-to-treatment time with the NIHSS score, has been shown to predict clinical outcomes. In this study, we assessed whether a similar combination of the ORT and the NIHSS score can be applied to predict the outcomes after endovascular therapy. We retrospectively reviewed the charts of 128 consecutive ischemic stroke patients with successful reperfusion after endovascular therapy. We analyzed the association of the ORT, the NIHSS score, and the NIHSS-time score with good outcome (modified Rankin Scale score ≤ 2 at 3 months). Good outcome rates for patients with NIHSS-time scores of 84.7 or lower, scores higher than 84.7 up to 127.5 or lower, and scores higher than 127.5 were 72.1%, 44.2%, and 14.3%, respectively (P < .01). Multivariate logistic regression analysis revealed that the NIHSS-time score was an independent predictor of good outcomes (odds ratio, .372; 95% confidence interval, .175-.789) after adjusting for age, sex, internal carotid artery occlusion, plasma glucose level, ORT, and NIHSS score. The NIHSS-time score can predict good clinical outcomes after endovascular treatment. Copyright © 2016 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  10. Analytical applications of glassy carbon electrodes modified with multi-wall carbon nanotubes dispersed in polyethylenimine as detectors in flow systems.

    PubMed

    Sánchez Arribas, Alberto; Bermejo, Esperanza; Chicharro, Manuel; Zapardiel, Antonio; Luque, Guillermina L; Ferreyra, Nancy F; Rivas, Gustavo A

    2007-07-23

    This work reports the advantages of using glassy carbon electrodes (GCEs) modified with multi-wall carbon nanotubes (CNT) dispersed in polyethylenimine (PEI) as detectors in flow injection and capillary electrophoresis. The presence of the dispersion of CNT in PEI at the electrode surface allows the highly sensitive and reproducible determination of hydrogen peroxide, different neurotransmitters (dopamine (D) and its metabolite dopac, epinephrine (E), norepinephrine (NE)), phenolic compounds (phenol (P), 3-chlorophenol (3-CP) and 2,3-dichlorophenol (2,3CP)) and herbicides (amitrol). Sensitivities enhancements of 150 and 140 folds compared to GCE were observed for hydrogen peroxide and amitrol, respectively. One of the most remarkable properties of the resulting electrode is the antifouling effect of the CNT/PEI layer. No passivation was observed either for successive additions (30) or continuous flow (for 30 min) of the compounds under investigation, even dopac or phenol. A critical comparison of the amperometric and voltammetric signal of these different analytes at bare- and PEI-modified glassy carbon electrodes and pyrolytic graphite electrodes is also included, demonstrating that the superior performance of CNT is mainly due to their unique electrochemical properties. Glassy carbon electrodes modified with CNT-PEI dispersion also show an excellent performance as amperometric detector in the electrophoretic separation of phenolic compounds and neurotransmitters making possible highly sensitive and reproducible determinations.

  11. Clinical Utility of Angiographic CT with a Flat-detector Angiographic System during Endovascular Procedure

    PubMed Central

    Choi, Seon Woong; Jo, Kwang Wook; Kim, Young Woo; Kim, Seong Rim; Park, Ik Seong

    2016-01-01

    Objective We evaluated the feasibility of angiographic computed tomography (ACT) for visualizing stent material in patients who underwent intracranial or extracranial stent placement to treat atherosclerotic lesions or stent assisted coil embolization. Materials and Methods We performed intrarterial and intravenous ACT on biplane angiography system equipped with flat panel detectors (Axiom Arits dBA; Siemens Medical Solutions, Forchheim, Germany). Vistipaque 320 was injected for contrast medium, total 150 mL at flow rate of 5 mL/s through artery and 77 mL at flow rate of 3.5 mL/s through vein. Results ACT is a new imaging modality that provides a clear visualization of stent strut. Conclusion Therefore this new application has potential to become the noninvasive option for follow-up after endovascular surgery using stents. PMID:27847769

  12. Endovascular management of six simultaneous intracranial dural arteriovenous fistulas in a single patient.

    PubMed

    Gist, Taylor L; Rangel-Castilla, Leonardo; Krishna, Chandan; Roman, Gustavo C; Cech, David A; Diaz, Orlando

    2014-03-01

    A 64-year-old man with a history of traumatic brain injury 4 years previously presented with progressive cognitive decline and gait abnormality. MRI revealed diffusion restriction in the bilateral centrum semiovale and multiple serpiginous flow voids. Cerebral angiogram revealed a total of six intracranial dural arteriovenous fistulas with separate fistulas of the right and left sphenoid bones, left clival plexus, right transverse sinus, right sigmoid sinus, and superior sagittal sinus. A diffuse pseudophlebitic pattern of venous drainage indicating severe venous hypertension was also observed. The patient underwent a series of endovascular treatments over the next 10 months to achieve resolution of all arteriovenous shunting. Repeat MRI showed resolution of the diffusion restriction and marked reduction in T2 vascular flow voids. The patient's clinical status improved significantly over the course of treatment, paralleling the improvement in venous hypertension.

  13. Endovascular Treatment of Ruptured Iliac Aneurysm Previously Treated by Endovascular Means

    SciTech Connect

    Dalainas, Ilias Nano, Giovanni; Stegher, Silvia; Bianchi, Paolo; Malacrida, Giovanni; Tealdi, Domenico G.

    2008-03-15

    A patient with a ruptured iliac aneurysm was admitted to the Emergency Department in hypovolemic shock. He had previously undergone surgical treatment for an infrarenal abdominal aortic aneurysm, which was managed with a terminal-terminal Dacron tube graft. Subsequently, he developed two iliac aneurysms, which were treated endovascularly with two wall-grafts in the right and one wall-graft in the left iliac arteries. He suffered chronic renal failure and arterial hypertension. Contrast-enhanced computed tomography showed rupture of the right iliac aneurysm and dislocation of the two wall-grafts. He was treated in an emergency situation with the implantation of an iliac endograft that bridged the two wall-grafts, which resulted in hemostasis and stabilization of his condition. Five days later, in an elective surgical situation, he was treated with the implantation of an aorto-uni-iliac endograft combined with a femoral-femoral bypass. He was discharged 5 days later in good condition. At the 4 year follow-up visit, the endoprosthesis remained in place with no evidence of an endoleak. In conclusion, overlapping of endografts should be avoided, if possible. Strict surveillance of the endovascularly treated patient remains mandatory.

  14. Endovascular recanalization of infrapopliteal occlusions in patients with critical limb ischemia

    PubMed Central

    Singh, Gagan D.; Armstrong, Ehrin J.; Yeo, Khung-Keong; Singh, Satinder; Westin, Gregory G.; Pevec, William C.; Dawson, David L.; Laird, John R.

    2014-01-01

    Background Endovascular therapies are increasingly used for treatment of critical limb ischemia (CLI). Infrapopliteal (IP) occlusions are common in CLI, and successful limb salvage may require restoration of arterial flow in the distribution of a chronically occluded vessel. We sought to describe the procedural characteristics and outcomes of patients with IP occlusions who underwent endovascular intervention for treatment of CLI. Methods All patients with IP interventions for treatment of CLI from 2006 to 2012 were included. Angiographic and procedural data were compared between patients who underwent intervention for IP occlusions vs IP stenosis. Restenosis was determined by Doppler ultrasound imaging. Limb salvage was the primary end point of the study. Additional end points included primary patency, primary assisted patency, secondary patency, occlusion crossing success, procedural success, and amputation-free survival. Results A total of 187 patients with CLI underwent interventions for 356 IP lesions, and 77 patients (41%) had interventions for an IP occlusion. Patients with an intervention for IP occlusion were more likely to have zero to one vessel runoff (83% vs 56%; P < .001) compared with interventions for stenosis. Compared with IP stenoses, IP occlusions were longer (118 ± 86 vs 73 ± 67 mm; P < .001) and had a smaller vessel diameter (2.5 ± 0.8 vs 2.7 ± 0.5 mm; P =.02). Wire crossing was achieved in 83% of IP occlusions, and the overall procedural success for IP occlusions was 79%. The overall 1-year limb salvage rate was 84%. Limb salvage was highest in the stenosis group, slightly lower in the successful occlusion group, and lowest in the failed occlusion group (92% vs 75% vs 58%, respectively; P = .02). Unsuccessfully treated IP occlusions were associated with a significantly higher likelihood of major amputation (hazard ratio, 5.79; 95% confidence interval, 1.89–17.7) and major amputation or death (hazard ratio, 2.69; 95% confidence interval

  15. Sharply curved turn around duct flow predictions using spectral partitioning of the turbulent kinetic energy and a pressure modified wall law

    NASA Technical Reports Server (NTRS)

    Santi, L. Michael

    1986-01-01

    Computational predictions of turbulent flow in sharply curved 180 degree turn around ducts are presented. The CNS2D computer code is used to solve the equations of motion for two-dimensional incompressible flows transformed to a nonorthogonal body-fitted coordinate system. This procedure incorporates the pressure velocity correction algorithm SIMPLE-C to iteratively solve a discretized form of the transformed equations. A multiple scale turbulence model based on simplified spectral partitioning is employed to obtain closure. Flow field predictions utilizing the multiple scale model are compared to features predicted by the traditional single scale k-epsilon model. Tuning parameter sensitivities of the multiple scale model applied to turn around duct flows are also determined. In addition, a wall function approach based on a wall law suitable for incompressible turbulent boundary layers under strong adverse pressure gradients is tested. Turn around duct flow characteristics utilizing this modified wall law are presented and compared to results based on a standard wall treatment.

  16. Influence of high-flow modified ultrafiltration on brain oxygenation and perfusion during surgery for children with ventricular septal defects: a pilot study.

    PubMed

    Jia, Zaishen; Teng, Yichao; Liu, Yuan; Wang, Hong; Li, Yue; Hou, Xiaotong

    2017-10-01

    Modified ultrafiltration (MUF) can be performed in infants with ventricular septal defects (VSDs) after cardiopulmonary bypass (CPB) to reduce haemodilution and its potential adverse effects. High-flow MUF might reduce ultrafiltration duration and hasten the necessary correction of haemodilution during CPB. However, its influence on brain oxygenation remains controversial. This non-randomized, prospective, pilot study aimed to investigate the influence of high-flow MUF on brain oxygenation in infants with VSDs. High-flow MUF (≥20 mL/kg/min) was performed in twenty infants. Brain oxygen saturation (rSO2) and tissue haemoglobin index (tHI) were non-invasively and continuously measured intraoperatively using near-infrared spectroscopy (NIRS). Transcranial Doppler non-invasively detected the mean flow velocity of the middle cerebral artery (Vmean). rSO2 increased significantly during MUF, as did tHI, Vmean, mean arterial pressure and haematocrit (all p<0.05). No correlation was found between changes in rSO2 and changes in other parameters (all p≥0.05). In infants with ventricular septal defects managed with CPB during VSDs repair, high-flow MUF did not reduce brain oxygenation.

  17. Endovascular Treatment of Wide-Necked Visceral Artery Aneurysms Using the Neurovascular Comaneci Neck-Bridging Device: A Technical Report.

    PubMed

    Maingard, Julian; Kok, Hong Kuan; Phelan, Emma; Logan, Caitriona; Ranatunga, Dinesh; Brooks, Duncan Mark; Chandra, Ronil V; Lee, Michael J; Asadi, Hamed

    2017-06-29

    Visceral and renal artery aneurysms (VRAAs) are an uncommon clinical entity but carry a risk of rupture with associated morbidity and mortality. The rupture risk is particularly high when the aneurysms are large, of unfavourable morphology or in the setting of pregnancy and perioperative period. Endovascular approaches are now first line in the treatment of VRAA, but conventional techniques may be ineffective in excluding aneurysms with unfavourable anatomy such as those with wide necks or at arterial bifurcation points. The neurovascular Comaneci neck-bridging device is used to temporarily cover the neck of intracranial aneurysms without occluding forward arterial flow during endovascular coiling. We report the novel use of the Comaneci neck-bridging device for the treatment of complex peripheral VRAAs. We describe the treatment of two patients with renal and splenic artery aneurysms demonstrating unfavourable anatomic morphology for conventional endovascular approaches. In the first patient, the renal artery aneurysm was situated at the intrarenal bifurcation of the main renal artery in the setting of a solitary kidney. In the second patient, the splenic artery aneurysm was situated close to the splenic hilum at the distal splenic arterial bifurcation. The Comaneci neck-bridging device was successfully used in both cases to assist coil embolisation with visceral preservation. The Comaneci neck-bridging device is potentially safe and effective for the treatment of peripheral VRAA with unfavourable anatomic characteristics that would have been deemed unsuitable for treatment using conventional techniques. Level 4, Technical Report.

  18. Two-year clinical follow-up of the Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in The Netherlands (MR CLEAN): design and statistical analysis plan of the extended follow-up study.

    PubMed

    van den Berg, Lucie A; Dijkgraaf, Marcel G W; Berkhemer, Olvert A; Fransen, Puck S S; Beumer, Debbie; Lingsma, Hester; Majoie, Charles B M; Dippel, Diederik W J; van der Lugt, Aad J; van Oostenbrugge, Robert J; van Zwam, Wim H; Roos, Yvo B W E M

    2016-11-22

    MR CLEAN was the first randomized trial to demonstrate the short-term clinical effectiveness of endovascular treatment in patients with acute ischemic stroke caused by large vessel occlusion in the anterior circulation. Several other trials confirmed that endovascular treatment improves clinical outcome at three months. However, limited data are available on long-term clinical outcome. We aimed to estimate the effect of endovascular treatment on functional outcome at two-year follow-up in patients with acute ischemic stroke. Secondly, we aimed to assess the effect of endovascular treatment on major vascular events and mortality during two years of follow-up. MR CLEAN is a multicenter clinical trial with randomized treatment allocation, open-label treatment, and blinded endpoint evaluation. Patients included were 18 years or older with acute ischemic stroke caused by a proven anterior proximal artery occlusion who could be treated within six hours after stroke onset. The intervention contrast was endovascular treatment and usual care versus no endovascular treatment and usual care. The current study extended the follow-up duration from three months to two years. The primary outcome is the score on the modified Rankin scale at two years. Secondary outcomes include all-cause mortality and the occurrence of major vascular events within two years of follow-up. The results of our study provide information on the long-term clinical effectiveness of endovascular treatment, which may have implications for individual treatment decisions and estimates of cost-effectiveness. NTR1804 . Registered on 7 May 2009; ISRCTN10888758 . Registered on 24 July 2012 (main MR CLEAN trial); NTR5073 . Registered on 26 February 2015 (extended follow-up study).

  19. Endovascular management of postoperative pseudoaneurysms of the external carotid artery.

    PubMed

    Cohen, José E; Gomori, John M; Moscovici, Samuel; Grigoriadis, Savvas; Ramirez de Noriega, Fernando; Itshayek, Eyal

    2012-05-01

    Hemorrhage secondary to postoperative pseudoaneurysm is a rare event, but may complicate the clinical course of straightforward and common interventions such as sinonasal procedures, tonsillectomy, and maxillofacial and plastic surgeries. We report our experience with the endovascular management of iatrogenic pseudoaneurysm in eight patients who had undergone recent craniomaxillofacial surgery. Computed tomography (CT), including CT-angiography, detected only three of the eight lesions. In all patients, endovascular embolization achieved successful occlusion of the pseudoaneurysm without local or general procedure-related complications. Immediate proximal arterial occlusion with detachable coils was performed in every case, and pseudoaneurysm coiling was performed in three cases presenting with active hemorrhage. Endovascular therapy proved to be safe and effective in the management of postoperative pseudoaneurysms. Surgeons involved in the craniomaxillofacial procedures should be aware of this complication and its management. Copyright © 2011 Elsevier Ltd. All rights reserved.

  20. Endovascular treatment of penetrating aortic ulcers: mid-term results.

    PubMed

    Dalainas, I; Nano, G; Medda, M; Bianchi, P; Casana, R; Ramponi, F; Stegher, S; Malacrida, G; Inglese, L; Tealdi, D G

    2007-07-01

    The aim of this study was to evaluate mid-term results of endovascular treatment of penetrating aortic ulcers. Between February 2000 and November 2006, 18 consecutive patients underwent endovascular treatment of the descending thoracic aorta (N=16) and abdominal infrarenal aorta (N=2) for penetrating aortic ulcer, in a single University Hospital. Data were prospectively collected and retrospectively analyzed. Mean follow-up was 41 months (range 4 to 77 months). Technical success was achieved in all patients. No perioperative deaths occurred. No conversion to open repair or secondary procedures were required. Two patients died in the follow-up period for reasons not related to penetrating aortic ulcers. One type II endoleak was observed. It was still present, unchanged, twelve months after the procedure. Endovascular treatment of penetrating aortic ulcers of the descending thoracic and infrarenal aorta were safe and effective in the mid-term in this small series of patients.

  1. Preprocedural planning for endovascular stent-graft placement.

    PubMed

    Kicska, Gregory; Litt, Harold

    2009-03-01

    Endovascular stent grafts have become a viable treatment for aortic thoracic and abdominal aneurysms in both elective and emergent situations. Computed tomographic (CT) angiography is the primary tool for determining eligibility for this procedure. This article discuses the preprocedural evaluation of an endovascular stent candidate. Evaluation begins with identification of the aneurysm pathology and its relationship to treatment efficacy. The radiologist must evaluate the aneurysm geometry for compatibility with stent hardware. Aneurysm features that suggest a contraindication must be recognized. Procedures that involve a combination of endovascular stenting and surgical revascularization are discussed so that the reader understands the limits of stent eligibility. Vascular access for stent placement must also be evaluated for the ability to accommodate stent delivery. The radiologist also must be familiar with CT imaging protocols and alternative methods of imaging that can evaluate stent feasibility. The utility of three-dimensional processing is discussed.

  2. Endovascular reperfusion therapies for acute ischemic stroke: dissecting the evidence.

    PubMed

    Tsivgoulis, Georgios; Safouris, Apostolos; Krogias, Christos; Arthur, Adam S; Alexandrov, Andrei V

    2016-05-01

    Ischemic stroke is a major cause of death and disability and intravenous thrombolysis has been the only approved acute reperfusion therapy (RT) for many years. Seven randomized-controlled clinical trials (RCTs) evaluating the safety and efficacy of endovascular therapy in patients with acute ischemic stroke (AIS) due to emergent large vessel occlusion (ELVO) have been recently published. These studies have changed the treatment paradigm by establishing mechanical thrombectomy (MT) as the most effective acute stroke therapy for improving functional outcome in anterior circulation ELVO with a NNT of 6. The present review will critically evaluate the results of these RCTs and of the existing meta-analyses investigating the safety and efficacy of endovascular therapy for AIS. Points of debate such as acute stroke imaging, posterior circulation stroke and general anesthesia will be addressed. We will also discuss health policies aiming to increase the availability of endovascular treatment for stroke patients.

  3. General Anesthesia Versus Conscious Sedation for Endovascular Treatment of Acute Ischemic Stroke: The AnStroke Trial (Anesthesia During Stroke).

    PubMed

    Löwhagen Hendén, Pia; Rentzos, Alexandros; Karlsson, Jan-Erik; Rosengren, Lars; Leiram, Birgitta; Sundeman, Henrik; Dunker, Dennis; Schnabel, Kunigunde; Wikholm, Gunnar; Hellström, Mikael; Ricksten, Sven-Erik

    2017-06-01

    Retrospective studies have found that patients receiving general anesthesia for endovascular treatment in acute ischemic stroke have worse neurological outcome compared with patients receiving conscious sedation. In this prospective randomized single-center study, we investigated the impact of anesthesia technique on neurological outcome in acute ischemic stroke patients. Ninety patients receiving endovascular treatment for acute ischemic stroke in 2013 to 2016 were included and randomized to general anesthesia or conscious sedation. Difference in neurological outcome at 3 months, measured as modified Rankin Scale score, was analyzed (primary outcome) and early neurological improvement of National Institutes of Health Stroke Scale and cerebral infarction volume. Age, sex, comorbidities, admission National Institutes of Health Stroke Scale score, intraprocedural blood pressure, blood glucose, Paco2 and Pco2 modified Thrombolysis in Cerebral Ischemia score, and relevant time intervals were recorded. In the general anesthesia group 19 of 45 patients (42.2%) and in the conscious sedation group 18 of 45 patients (40.0%) achieved a modified Rankin Scale score ≤2 (P=1.00) at 3 months, with no differences in intraoperative blood pressure decline from baseline (P=0.57); blood glucose (P=0.94); PaCO2 (P=0.68); time intervals (P=0.78); degree of successful recanalization, 91.1% versus 88.9% (P=1.00); National Institutes of Health Stroke Scale score at 24 hours 8 (3-5) versus 9 (2-15; P=0.60); infarction volume, 20 (10-100) versus 20(10-54) mL (P=0.53); and hospital mortality (13.3% in both groups; P=1.00). In endovascular treatment for acute ischemic stroke, no difference was found between general anesthesia and conscious sedation in neurological outcome 3 months after stroke. URL: https://www.clinicaltrials.gov. Unique identifier: NCT01872884. © 2017 American Heart Association, Inc.

  4. Results of tests performed on the Acoustic Quiet Flow Facility Three-Dimensional Model Tunnel: Report on the Modified D.S.M.A. Design

    NASA Technical Reports Server (NTRS)

    Barna, P. S.

    1996-01-01

    Numerous tests were performed on the original Acoustic Quiet Flow Facility Three-Dimensional Model Tunnel, scaled down from the full-scale plans. Results of tests performed on the original scale model tunnel were reported in April 1995, which clearly showed that this model was lacking in performance. Subsequently this scale model was modified to attempt to possibly improve the tunnel performance. The modifications included: (a) redesigned diffuser; (b) addition of a collector; (c) addition of a Nozzle-Diffuser; (d) changes in location of vent-air. Tests performed on the modified tunnel showed a marked improvement in performance amounting to a nominal increase of pressure recovery in the diffuser from 34 percent to 54 percent. Results obtained in the tests have wider application. They may also be applied to other tunnels operating with an open test section not necessarily having similar geometry as the model under consideration.

  5. Endovascular dialysis interventions in the era of DOQI.

    PubMed

    Greenberg, Joshua I; Suliman, Ahmed; Angle, Niren

    2008-09-01

    The National Kidney Foundation Dialysis Outcomes and Quality Initiative (DOQI) recommends autogenous fistulae as the preferred access for new dialysis procedures. Unfortunately, despite superior patency rates compared to prosthetic grafts, even autogenous access durability is often undermined by venous stenosis due to intimal hyperplasia at the outflow vein or by central venous stenosis due to long-standing central venous catheters. Salvage interventions, in the form of endovascular treatments such as percutaneous transluminal angioplasty (PTA) and/or stenting, are increasingly utilized for access salvage and maintenance. The objective of this study was to evaluate the efficacy of endovascular dialysis interventions in the era of DOQI. A retrospective review of a database of endovascular interventions for dialysis access during 36 months at an academic medical center was performed. Both central venous and access outflow lesions were included in the analysis. Kaplan-Meier curves and log-rank analysis were used to assess and compare time-dependent variables. Forty-five patients with dialysis access underwent 72 endovascular interventions for access maintenance. There were 27 central venous and 32 outflow endovascular interventions with 98% follow-up. Primary and assisted primary patency rates for outflow balloon PTA were 50% and 72% at 12 months, respectively. There were 1.1 reinterventions required per index outflow PTA procedure. Postintervention primary patency rates for central venous PTA were 30% and 9% at 6 and 12 months, respectively. Postintervention assisted patency for central venous PTA was 100% at 12 months, requiring 1.8 reinterventions per index PTA. Central venous and venous outflow interventions extended overall access patency by 38.5 and 33 months, respectively (p < 0.0001). Endovascular interventions are the mainstay of treatment for the malfunctioning dialysis access. Despite the need for multiple reinterventions and close surveillance, catheter

  6. Management of giant intracranial ICA aneurysms with combined extracranial-intracranial anastomosis and endovascular occlusion.

    PubMed

    Serbinenko, F A; Filatov, J M; Spallone, A; Tchurilov, M V; Lazarev, V A

    1990-07-01

    Nine patients with giant internal carotid artery (ICA) aneurysms (greater than 2.5 cm in diameter) were subjected to a combined extracranial-intracranial (EC-IC) bypass procedure and endovascular ICA occlusion during 1987 and 1988. The procedures were performed under one anesthetic. In all cases the collateral circulation had been judged insufficient on the basis of a strict preoperative testing protocol including: cerebral panangiography, electroencephalography, somatosensory potential recording, and cerebral blood flow monitoring during manual compression of the ICA in the neck. There were four intracavernous ICA aneurysms, four carotid-ophthalmic artery aneurysms, and one supraclinoid ICA aneurysm. All patients showed symptoms and signs of compression of the surrounding nervous structures. In the five cases of intradural lesions, the artery was occluded at the level of the aneurysm neck, so the ophthalmic artery had to be occluded. There was, nevertheless, no case of worsening of vision following surgery, and all nine patients showed significant improvement following the combined procedure. A combined EC-IC bypass procedure and endovascular ICA occlusion allows for immediate verification of the surgical results and appears to be a worthwhile method for treating giant intracranial aneurysms.

  7. Which is the best revascularization for critical limb ischemia: Endovascular or open surgery?

    PubMed

    Beard, Jonathan D

    2008-12-01

    This review considers the roles of endovascular and open surgery for critical lower limb ischemia. The TransAtlantic Inter-Society Consensus document offers sensible guidelines for the treatment of both suprainguinal and infrainguinal disease. For bilateral/diffuse suprainguinal disease, aortobifemoral bypass remains the best option, but great care should be taken in this new era of hospital-acquired infection. Unilateral iliac occlusions should be treated by primary stenting, but an iliofemoral or femorofemoral bypass may be the best option when the disease extends down into the common femoral artery. Stents may reduce the risk of embolization in iliac stenoses but probably confer no benefit in long-term patency. Iliac stenoses should be treated by angioplasty, with stents reserved for flow-limiting complications. Although infrainguinal bypass surgery is in decline, probably due to better medical treatment and more endovascular intervention, bypass using autologous saphenous vein remains the gold standard. In the absence of leg veins, arm vein should be considered. Prosthetic grafts should be used as a last resort, and only with a venous cuff. The long-term results of the Bypass Versus Angioplasty in Severe Ischemia of the Leg (BASIL) trial favor surgery rather than angioplasty if there is a good vein and the patient is fit. Further randomized studies of infrainguinal stenting vs bypass are required. Some patients with critical lower limb ischemia are best treated by analgesia or primary amputation.

  8. Endovascular Repair of a Secondary Aorto-Appendiceal Fistula

    SciTech Connect

    Tse, Donald M. L.; Thompson, Andrew R. A.; Perkins, Jeremy; Bratby, Mark J.; Anthony, Susan; Uberoi, Raman

    2011-10-15

    Aortoenteric fistula (AEF) is an uncommon but serious complication occurring after aortic surgery and may occur at any site in the gastrointestinal tract, with the duodenum being the most common. Conventional surgical repair of secondary AEF has high mortality, whereas endovascular repair has emerged as an alternative treatment despite concerns about persistent or recurrent infection. We report the case of a 91-year old man who was admitted with rectal bleeding from an aorto-appendiceal fistula 9 years after open abdominal aortic aneurysm repair. This rare site for AEF was diagnosed on computed tomography, and we present the first case of endovascular treatment of this uncommon complication.

  9. Endovascular Treatment of a Renal Artery Branch Aneurysm

    SciTech Connect

    Malacrida, G.; Dalainas, Ilias Medda, Massimo; Nano, Giovanni; Inglese, Luigi

    2007-02-15

    A 58-year-old woman was admitted to our institution because of a left renal artery branch saccular aneurysm with a 2 cm diameter. Due to a hostile abdomen and the infrarenal location, an endovascular approach was chosen. A Jostent Peripheral Stent-Graft was placed under angiographic control, excluding the aneurysm from the circulation. No peri- or postprocedural complications were observed. At 6 months follow-up, the endograft is patent, excluding the aneurysm. Endovascular treatment may represent an alternative to surgery, especially in the distal infraparenchymal location.

  10. Endovascular treatment of true and false aneurysms in hemodialysis access.

    PubMed

    Hedin, U; Engström, J; Roy, J

    2015-08-01

    Formation of true and false aneurysms in vascular access for hemodialysis is a complication associated with an immediate or chronic threat to the patient, which jeopardizes access function for further dialysis. Although open surgical repair remains the established treatment of choice, during the last decade, endovascular procedures, largely utilizing stent grafts, have emerged as a viable option for treatment in emergencies as well as for elective cases. Here, basic concepts in vascular access aneurysm management are recapitulated and strategies for endovascular treatment of these complications discussed.

  11. Advances in the endovascular management of acute injury.

    PubMed

    Reed, Amy B

    2011-03-01

    Traumatic vascular injuries are common in the multi-injured patient. Exposure and repair can often be challenging, particularly in the pelvis, chest, and distal carotid arteries. The explosion of endovascular technology over the last decade has brought innovative strategies to managing vascular trauma in the injured patient.( 1 ) Hybrid operating rooms provide the perfect opportunity to perform arteriography, minimally invasive proximal control, and therapeutic intervention, be it endovascular, open, or a hybrid combination thereof. In the absence of a hybrid operating room, an angiographic table and portable C-arm in the operating room is certainly acceptable. Percutaneous and hybrid techniques to manage nonaortic arterial trauma will be reviewed.

  12. Anesthesia for Endovascular Approaches to Acute Ischemic Stroke.

    PubMed

    Avitsian, Rafi; Machado, Sandra B

    2016-09-01

    Involvement of the Anesthesiologist in the early stages of care for acute ischemic stroke patient undergoing endovascular treatment is essential. Anesthetic management includes the anesthetic technique (general anesthesia vs sedation), a matter of much debate and an area in need of well-designed prospective studies. The large numbers of confounding factors make the design of such studies a difficult process. A universally agreed point in the endovascular management of acute ischemic stroke is the importance of decreasing the time to revascularization. Hemodynamic and ventilatory management and implementation of neuroprotective modalities and treatment of acute procedural complications are important components of the anesthetic plan. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Endovascular Repair for Type A Aortic Dissection After Transcatheter Aortic Valve Replacement With a Medtronic CoreValve.

    PubMed

    Berfield, Kathleen K S; Sweet, Matthew P; McCabe, James M; Reisman, Mark; Mackensen, G Burkhard; Mokadam, Nahush A; Dean, Larry S; Smith, Jason W

    2015-10-01

    Transcatheter aortic valve replacement is being used with increasing frequency in patients with severe aortic stenosis who are otherwise deemed to be at high surgical risk. Aortic dissection is a rare complication of transcatheter aortic valve replacement and poses a unique management dilemma. We describe the treatment of an acute Stanford type A aortic dissection after transcatheter aortic valve replacement with a modified thoracic endovascular stent graft in a 95-year-old woman. Copyright © 2015 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  14. Leaching study of PNL 76-68 glass beads using the LLNL continuous-flow method and the PNL modified IAEA method. Final report

    SciTech Connect

    Coles, D.G.; Mensing, R.W.; Rego, J.; Weed, H.C.; Buddemeier, R.W.

    1982-10-04

    A long-term single-pass continuous-flow (SPCF) leaching test was conducted on the glass waste form PNL 76-68. Leaching rates of Np, Pu and various stable elements were measured at 25 and 75/sup 0/C with three different solutions and three different flow rates. The SPCF leaching results were compared with results of a modified IAEA leach test performed by Pacific Northwest Laboratories (PNL). Elemental leach rates and their variation with temperature, flow rate and solution composition were established. The LLNL and PNL leach test results appear to agree within experimental uncertainties. The magnitude of the leach rates determined for Np and the glass matrix elements is 10/sup -5/ grams of glass/cm/sup 2/ geometric solid surface area/day. The rates increase with temperature and with solution flow rate, and are similar in brine and distilled water but higher in a bicarbonate solution. Other cations exhibit somewhat different behavior, and Pu in particular yields a much lower apparent leach rate, probably because of sorption or precipitation effects after release from the glass matrix. After the initial few days, most elements are leached at a constant rate. Matrix dissolution appears to be the most probable rate controlling step for the leaching of most elements. 23 figures, 12 tables.

  15. Leaching study of PNL 76-68 glass beads using the LLNL continuous-flow method and the PNL-modified IAEA method. Final report

    SciTech Connect

    Buddemeier, R.W.; Coles, D.G.; Mensing, R.W.; Rego, J.; Weed, H.C.

    1982-08-20

    Lawrence Livermore National Laboratory (LLNL) has conducted a long-term single-pass continuous-flow (SPCF) leaching test of the glass waste form PNL 76-68. Leaching rates of Np, Pu, and various stable elements were measured at 25/sup 0/ and 75/sup 0/C with three different solutions and three different flow rates. The purposes of the study were: (1) to compare SPCF leaching results with the results of a modified IAEA leach test performed by Pacific Northwest Laboratories (PNL); (2) to establish elemental leach rates and their variation with temperature, flow rate and solution composition; and (3) to gain insight into the leaching mechanisms. The LLNL and PNL leach tests yielded results which appear to agree within experimental uncertainties. The magnitude of the leach rates determined for Np and the glass matrix elements is 10/sup -5/ grams of glass/cm/sup 2/ geometric solid surface area/day. The rates increase with temperature and with solution flow rate, and are similar in brine and distilled water but higher in a bicarbonate solution. Other cations exhibit somewhat different behavior, and Pu in particular yields a much lower apparent leach rate, probably because of sorption or precipitation effects after release from the glass matrix. After the initial few days, most elements are leached at a constant rate. Matrix dissolution appears to be the most probable rate controlling step for the leaching of most elements.

  16. When do plants modify fluvial processes? Plant-hydraulic interactions under variable flow and sediment supply rates

    NASA Astrophysics Data System (ADS)

    Manners, Rebecca B.; Wilcox, Andrew C.; Kui, Li; Lightbody, Anne F.; Stella, John C.; Sklar, Leonard S.

    2015-02-01

    Flow and sediment regimes shape alluvial river channels; yet the influence of these abiotic drivers can be strongly mediated by biotic factors such as the size and density of riparian vegetation. We present results from an experiment designed to identify when plants control fluvial processes and to investigate the sensitivity of fluvial processes to changes in plant characteristics versus changes in flow rate or sediment supply. Live seedlings of two species with distinct morphologies, tamarisk (Tamarix spp.) and cottonwood (Populus fremontii), were placed in different configurations in a mobile sand-bed flume. We measured the hydraulic and sediment flux responses of the channel at different flow rates and sediment supply conditions representing equilibrium (sediment supply = transport rate) and deficit (sediment supply < transport rate). We found that the hydraulic and sediment flux responses during sediment equilibrium represented a balance between abiotic and biotic factors and was sensitive to increasing flow rates and plant species and configuration. Species-specific traits controlled the hydraulic response: compared to cottonwood, which has a more tree-like morphology, the shrubby morphology of tamarisk resulted in less pronation and greater reductions in near-bed velocities, Reynolds stress, and sediment flux rates. Under sediment-deficit conditions, on the other hand, abiotic factors dampened the effect of variations in plant characteristics on the hydraulic response. We identified scenarios for which the highest stem-density patch, independent of abiotic factors, dominated the fluvial response. These results provide insight into how and when plants influence fluvial processes in natural systems.

  17. On-site detection of stacked genetically modified soybean based on event-specific TM-LAMP and a DNAzyme-lateral flow biosensor.

    PubMed

    Cheng, Nan; Shang, Ying; Xu, Yuancong; Zhang, Li; Luo, Yunbo; Huang, Kunlun; Xu, Wentao

    2017-05-15

    Stacked genetically modified organisms (GMO) are becoming popular for their enhanced production efficiency and improved functional properties, and on-site detection of stacked GMO is an urgent challenge to be solved. In this study, we developed a cascade system combining event-specific tag-labeled multiplex LAMP with a DNAzyme-lateral flow biosensor for reliable detection of stacked events (DP305423× GTS 40-3-2). Three primer sets, both event-specific and soybean species-specific, were newly designed for the tag-labeled multiplex LAMP system. A trident-like lateral flow biosensor displayed amplified products simultaneously without cross contamination, and DNAzyme enhancement improved the sensitivity effectively. After optimization, the limit of detection was approximately 0.1% (w/w) for stacked GM soybean, which is sensitive enough to detect genetically modified content up to a threshold value established by several countries for regulatory compliance. The entire detection process could be shortened to 120min without any large-scale instrumentation. This method may be useful for the in-field detection of DP305423× GTS 40-3-2 soybean on a single kernel basis and on-site screening tests of stacked GM soybean lines and individual parent GM soybean lines in highly processed foods.

  18. 3D-Printed Fluidic Devices for Nanoparticle Preparation and Flow-Injection Amperometry Using Integrated Prussian Blue Nanoparticle-Modified Electrodes

    PubMed Central

    Bishop, Gregory W.; Satterwhite, Jennifer E.; Bhakta, Snehasis; Kadimisetty, Karteek; Gillette, Kelsey M.; Chen, Eric; Rusling, James F.

    2015-01-01

    A consumer-grade fused filament fabrication (FFF) 3D printer was used to construct fluidic devices for nanoparticle preparation and electrochemical sensing. Devices were printed using poly(ethylene terephthalate) and featured threaded ports to connect polyetheretherketone (PEEK) tubing via printed fittings prepared from acrylonitrile butadiene styrene (ABS). These devices included channels designed to have 800 × 800 µm2 square cross sections and were semitransparent to allow visualization of the solution-filled channels. A 3D-printed device with a Y-shaped mixing channel was used to prepare Prussian blue nanoparticles (PBNPs) under flow rates of 100 to 2000 µL min−1. PBNPs were then attached to gold electrodes for hydrogen peroxide sensing. 3D-printed devices used for electrochemical measurements featured threaded access ports into which a fitting equipped with reference, counter, and PBNP-modified working electrodes could be inserted. PBNP-modified electrodes enabled amperometric detection of H2O2 in the 3D-printed channel by flow-injection analysis, exhibiting a detection limit of 100 nM and linear response up to 20 µM. These experiments show that a consumer-grade FFF printer can be used to fabricate low-cost fluidic devices for applications similar to those that have been reported with more expensive 3D-printing methods. PMID:25901660

  19. 3D-Printed Fluidic Devices for Nanoparticle Preparation and Flow-Injection Amperometry Using Integrated Prussian Blue Nanoparticle-Modified Electrodes.

    PubMed

    Bishop, Gregory W; Satterwhite, Jennifer E; Bhakta, Snehasis; Kadimisetty, Karteek; Gillette, Kelsey M; Chen, Eric; Rusling, James F

    2015-01-01

    A consumer-grade fused filament fabrication (FFF) 3D printer was used to construct fluidic devices for nanoparticle preparation and electrochemical sensing. Devices were printed using poly(ethylene terephthalate) and featured threaded ports to connect polyetheretherketone (PEEK) tubing via printed fittings prepared from acrylonitrile butadiene styrene (ABS). These devices included channels designed to have 800 μm × 800 μm square cross sections and were semitransparent to allow visualization of the solution-filled channels. A 3D-printed device with a Y-shaped mixing channel was used to prepare Prussian blue nanoparticles (PBNPs) under flow rates of 100 to 2000 μL min(-1). PBNPs were then attached to gold electrodes for hydrogen peroxide sensing. 3D-printed devices used for electrochemical measurements featured threaded access ports into which a fitting equipped with reference, counter, and PBNP-modified working electrodes could be inserted. PBNP-modified electrodes enabled amperometric detection of H2O2 in the 3D-printed channel by flow-injection analysis, exhibiting a detection limit of 100 nM and linear response up to 20 μM. These experiments show that a consumer-grade FFF printer can be used to fabricate low-cost fluidic devices for applications similar to those that have been reported with more expensive 3D-printing methods.

  20. Highly active, bi-functional and metal-free B4C-nanoparticle-modified graphite felt electrodes for vanadium redox flow batteries

    NASA Astrophysics Data System (ADS)

    Jiang, H. R.; Shyy, W.; Wu, M. C.; Wei, L.; Zhao, T. S.

    2017-10-01

    The potential of B4C as a metal-free catalyst for vanadium redox reactions is investigated by first-principles calculations. Results show that the central carbon atom of B4C can act as a highly active reaction site for redox reactions, due primarily to the abundant unpaired electrons around it. The catalytic effect is then verified experimentally by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) tests, both of which demonstrate that B4C nanoparticles can enhance the kinetics for both V2+/V3+ and VO2+/VO2+ redox reactions, indicating a bi-functional effect. The B4C-nanoparticle-modified graphite felt electrodes are finally prepared and tested in vanadium redox flow batteries (VRFBs). It is shown that the batteries with the prepared electrodes exhibit energy efficiencies of 88.9% and 80.0% at the current densities of 80 and 160 mA cm-2, which are 16.6% and 18.8% higher than those with the original graphite felt electrodes. With a further increase in current densities to 240 and 320 mA cm-2, the batteries can still maintain energy efficiencies of 72.0% and 63.8%, respectively. All these results show that the B4C-nanoparticle-modified graphite felt electrode outperforms existing metal-free catalyst modified electrodes, and thus can be promising electrodes for VRFBs.

  1. Results of Endovascular Management for Mid-Basilar Artery Aneurysms

    PubMed Central

    Zhang, J.; Zhang, R.; Wu, Z.; Lv, X.; Liu, B.

    2010-01-01

    We evaluated the results of endovascular management of patients with mid-basilar artery aneurysm (mBAA). During a seven year period, 14 patients (mean age 39.6 years, male/female ratio 1:1) with mBAA were treated with endovascular techniques at our institute. Pretreatment clinical grades were determined using the Hunt-Hess scale. Outcome was evaluated using the Glasgow Outcome Scale scores (GOS) during a mean follow-up period of 15.6 months (range, three to 70 months). Fourteen patients with 15 mBAAs were treated endovascularly. Four (28.6%) patients died of rebleeding within one day after embolization. In ten mBAAs, immediate postprocedural angiograms showed that complete occlusion was achieved, subtotal occlusion in one, and incomplete occlusion in four. Follow-up angiographic results in ten patients confirmed complete occlusion of 11 aneurysms. Long-term outcome was good (GOS Score 4 or 5) in ten patients (71.4%) and fatal (GOS Score 1) in four (28.6%). Favorable overall long-term outcome can be achieved in 78.6% patients with mBAAs. Endovascular management of mBAAs is an effective treatment in the long-term. In our experience, the natural history of mBAAs is dismal. PMID:20977855

  2. Bronchial Aneurysms Mimicking Aortic Aneurysms: Endovascular Treatment in Two Patients

    SciTech Connect

    Vernhet, Helene; Bousquet, Claudine; Jean, Betty; Lesnik, Alvian; Durand, Gerard; Giron, Jacques; Senac, Jean Paul

    1999-05-15

    Bronchial artery dilatation and aneurysm formation is a potential complication of local inflammation, especially in bronchiectasis. When the bronchial artery has an ectopic origin from the inferior segment of the aortic arch, aneurysms may mimick aortic aneurysms. Despite this particular location, endovascular treatment is possible. We report two such aneurysms that were successfully embolized with steel coils.

  3. Endovascular treatment of traumatic injuries of the vertebral artery.

    PubMed

    Herrera, D A; Vargas, S A; Dublin, A B

    2008-09-01

    There are a few reports regarding the treatment of traumatic vertebral arteriovenous fistulas and pseudoaneurysms. Our aim was to describe the clinical and angiographic results of endovascular therapy for traumatic injuries of the vertebral artery. The clinical and angiographic features of 18 traumatic injuries of the vertebral artery during an 8-year period were reviewed. There were 14 male (78%) and 4 female patients (22%). The average age was 28 years (range, 11-49 years). Of the 18 lesions of the vertebral artery, 17 (95%) were the result of penetrating trauma (gunshot or stab wound injury) and 1 (5%) was iatrogenic (jugular vein catheter). In 16 (89%) instances, the injury resulted in an arteriovenous fistula, and in the other 2 (11%), in a pseudoaneurysm. All patients were treated with an endovascular approach by using different techniques (balloon occlusion, coil embolization, and/or stent deployment). Endovascular therapy resulted in immediate lesion total occlusion in 16 (89%) patients. Delayed total occlusion was demonstrated angiographically during follow-up in the 2 remaining patients. Clinical improvement was documented in all patients, and there were no clinically symptomatic complications. In this small series, endovascular techniques were a safe and effective method of treatment and were not associated with significant morbidity or mortality.

  4. Endovascular revascularization and free tissue transfer for lower limb salvage.

    PubMed

    Huang, Chieh-Chi; Chang, Chien-Hwa; Hsu, Honda; Mark Chiu, Chih-Hung; Lin, Chih-Ming; Lee, Jiunn-Tat; Chien, Sou-Hsin

    2014-10-01

    Combined bypass surgery with free flap reconstruction is an established method for lower limb salvage. But the success of the combination of endovascular revascularization together with free tissue transfer has so far not been well established. A retrospective review of all patients who had undergone endovascular revascularization and reconstructed with free tissue transfer for lower limb salvage at Tzu Chi Dalin General Hospital between 2008 and 2012 was performed. A total of 26 legs underwent limb salvage in 24 patients. There were 10 male and 14 female patients. Their average age was 71.4 years. The average time interval between endovascular intervention and free tissue transfer was 8 days. There was 100% flap survival but partial flap necrosis was seen in three patients. A high rate of wound infection was seen in eight patients, all requiring further debridement. The total limb salvage rate at 1-year follow-up was 96% and 92% at the 2-year follow-up. In conclusion, the success rate of lower limb salvage using a combination of endovascular revascularization and free tissue reconstruction is comparable to using a combination of bypass surgery and free tissue transfer. It is associated with a high flap success rate and a high limb salvage rate. It provides physicians with a further treatment option in the management of ischemic lower limbs with extended tissue loss.

  5. Endovascular treatment of spontaneous isolated abdominal aortic dissection

    PubMed Central

    Giribono, Anna Maria; Ferrara, Doriana; Spalla, Flavia; Narese, Donatella; Bracale, Umberto; Pecoraro, Felice; Bracale, Renata; del Guercio, Luca

    2016-01-01

    Isolated abdominal aortic dissection is a rare clinical disease representing only 1.3% of all dissections. There are a few case series reported in the literature. The causes of this pathology can be spontaneous, iatrogenic, or traumatic. Most patients are asymptomatic and symptoms are usually abdominal or back pain, while claudication and lower limb ischemia are rare. Surgical and endovascular treatment are two valid options with acceptable results. We herein describe nine cases of symptomatic spontaneous isolated abdominal aortic dissection, out of which four successfully were treated with an endovascular approach between July 2003 and July 2013. All patients were men, smokers, symptomatic (either abdominal or back pain or lower limb ischemia), with a history of high blood pressure, with a medical history negative for concomitant aneurysmatic dilatation or previous endovascular intervention. Diagnosis of isolated abdominal aortic dissection were established by contrast-enhanced computed tomography angiography (CTA) of the thoracic and abdominal aorta. All nine patients initially underwent medical treatment. In four symptomatic cases, non-responsive to medical therapy, bare-metal stents or stent grafts were successfully positioned. All patients completed a CTA follow-up of at least 12 months, during which they remained symptom-free. Endovascular management of this condition is associated with a high rate of technical success and a low mortality; therefore, it can be considered the treatment of choice when it is feasible. PMID:27994881

  6. Intraarterial Thrombolysis for Thromboemboli Associated with Endovascular Aneurysm Coiling

    PubMed Central

    Koebbe, C.J.; Horowitz, M.B.; Levy, E.I.; Dutton, K.; Jungries, C.C.; Purdy, P.D

    2002-01-01

    Summary With the rapidly developing applications of GDC endovascular aneurysm embolization, the recognition and treatment of potential intra-procedural complications is crucial to reducing the morbidity and mortality of this procedure. Thromboembolic complications occur with an incidence of 2-11 % with endovascular aneurysm coiling. We describe five cases in which the intraarterial use of thrombolytics was applied to disrupt a fresh clot and recanalize the occluded vessels with variable angiographic and clinical success. Five cases are presented in which thromboembolic complications occurred during or shortly after GDC endovascular aneurysm occlusion. The complication was recognized while depositing coils in two cases, on post-embolization angiogram in one, and a few hours following embolization in two cases in which a new neurologic deficit developed in the ICU. In those cases recognized while the microcatheter was near the aneurysm site, immediate thrombolysis was performed at the site of occlusion. The patients who developed a new neurologic deficit were returned to the endovascular suite and the site of occlusion was noted to be distal to the coiled aneurysm. Clot disruption was performed with the microcatheter before delivering intraarterial thrombolytics. Thromboembolic complications of GDC aneurysm embolization are fortunately rare and can be managed with delivery of thrombolytic therapy at the site of occlusion. Intraarterial thrombolysis of fresh clot caused by GDC aneurysm occlusion can successfully open the occluded vessels but no