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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. Endovascular embolization

    MedlinePlus

    Treatment - endovascular embolism; Coil embolization; Cerebral aneurysm - endovascular; Coiling - endovascular; Saccular aneurysm - endovascular; Berry aneurysm - endovascular repair; Fusiform aneurysm repair - endovascular; Aneurysm repair - endovascular

  3. Efficient simulation of blood flow past complex endovascular devices using an adaptive embedding technique.

    PubMed

    Cebral, Juan R; Löhner, Rainald

    2005-04-01

    The simulation of blood flow past endovascular devices such as coils and stents is a challenging problem due to the complex geometry of the devices. Traditional unstructured grid computational fluid dynamics relies on the generation of finite element grids that conform to the boundary of the computational domain. However, the generation of such grids for patient-specific modeling of cerebral aneurysm treatment with coils or stents is extremely difficult and time consuming. This paper describes the application of an adaptive grid embedding technique previously developed for complex fluid structure interaction problems to the simulation of endovascular devices. A hybrid approach is used: the vessel walls are treated with body conforming grids and the endovascular devices with an adaptive mesh embedding technique. This methodology fits naturally in the framework of image-based computational fluid dynamics and opens the door for exploration of different therapeutic options and personalization of endovascular procedures. PMID:15822805

  4. Swirling flow can suppress monocyte adhesion in the flow disturbance zones of the endovascular stent.

    PubMed

    Chen, Zengsheng; Zhang, Xiwen; Deng, Xiaoyan

    2012-01-01

    Adhesion of monocytes (U-937 cells) along a silicone tube deployed with circular ring stents was studied to test the hypothesis that by intentionally inducing swirling flow in an endovascular stent, the adhesion of monocytes would be suppressed. The results revealed that under a normal flow condition, the flow disturbance created by the circular ring stents enhanced the adhesion of U-937 cells in the silicone tube. By inducing a swirling flow in the silicone tube, the average wall shear stress (WSS) in the tube with the circular ring stents was elevated and significantly suppressed the adhesion density of U-937 cells to the surface in the disturbed flow zones to a level equal to that when no stents were deployed in the tube. The results also showed that, due to the attenuation of the swirling flow along the tube, the adhesion density of U-937 cells increased monotonically along the tube, indicating that the adhesion density was negatively correlated with the strength of the swirling flow. Thus, the present study suggests that intentionally introducing swirling flow in an artery deployed with stents may be a solution to solve the problem of stent restenosis by restraining the adhesion of monocytes. PMID:23380900

  5. Using a Surgeon-modified Iliac Branch Device to Preserve the Internal Iliac Artery during Endovascular Aneurysm Repair: Single-center Experiences and Early Results

    PubMed Central

    Wu, Wei-Wei; Lin, Chen; Liu, Bao; Liu, Chang-Wei

    2015-01-01

    Background: To evaluate the feasibility of a new surgeon-modified iliac branch device (IBD) technique to maintain pelvic perfusion in the management of common iliac artery (CIA) aneurysm during endovascular aneurysm repair (EVAR). Methods: From January 2011 to December 2013, a new surgeon-modified IBD technique was performed in department of vascular surgery of Peking Union Medical College Hospital in five patients treated for CIA aneurysm with or without abdominal aortic aneurysm. A stent-graft limb was initially deployed in vitro, anastomosed with vascular graft, creating a modified IBD reloaded into a larger sheath, with or without a guidewire preloaded into the side branch. The reloaded IBD was then placed in the iliac artery, with a covered stent bridging internal iliac artery and the branch. Finally, a bifurcated stent-graft was deployed, and a limb device was used to connect the main body and IBD. Results: Technical successes were obtained in all patients. The mean follow-up length was 24 months (range: 6–38 months). All grafts remained patent without any sign of endoleaks. There were no aneurysm ruptures, deaths, or other complications related to pelvic flow. Conclusions: Using the surgeon-modified IBD to preserve pelvic flow is a feasible endovascular technique and an appealing solution for personalized treatment of CIA aneurysm during EVAR. PMID:25698203

  6. The expanding realm of endovascular neurosurgery: flow diversion for cerebral aneurysm management.

    PubMed

    Krishna, Chandan; Sonig, Ashish; Natarajan, Sabareesh K; Siddiqui, Adnan H

    2014-01-01

    The worldwide prevalence of intracranial aneurysms is estimated to be between 5% and 10%, with some demographic variance. Subarachnoid hemorrhage secondary to ruptured intracranial aneurysm results in devastating neurological outcomes, leaving the majority of victims dead or disabled. Surgical clipping of intracranial aneurysms remained the definitive mode of treatment until Guglielmi detachable coils were introduced in the 1990s. This revolutionary innovation led to the recognition of neurointervention/neuroendovascular surgery as a bona fide option for intracranial aneurysms. Constant evolution of endovascular devices and techniques supported by several prospective randomized trials has catapulted the endovascular treatment of intracranial aneurysms to its current status as the preferred treatment modality for most ruptured and unruptured intracranial aneurysms. We are slowly transitioning from the era of coils to the era of flow diverters. Flow-diversion technology and techniques have revolutionized the treatment of wide-necked, giant, and fusiform aneurysms, where the results of microsurgery or conventional neuroendovascular strategies have traditionally been dismal. Although the Pipeline Embolization Device (ev3-Covidien, Irvine, CA) is the only flow-diversion device approved by the Food and Drug Administration for use in the United States, others are commercially available in Europe and South America, including the Silk (Balt Extrusion, Montmorency, France), Flow-Redirection Endoluminal Device (FRED; MicroVention, Tustin, CA), Surpass (Stryker, Kalamazoo, MI), and p64 (Phenox, Bochum, Germany). Improvements in technology and operator experience and the encouraging results of clinical trials have led to broader acceptance for the use of these devices in cerebral aneurysm management. Continued innovation and refinement of endovascular devices and techniques will inevitably improve technical success rates, reduce procedure-related complications, and broaden the

  7. The Expanding Realm of Endovascular Neurosurgery: Flow Diversion for Cerebral Aneurysm Management

    PubMed Central

    Krishna, Chandan; Sonig, Ashish; Natarajan, Sabareesh K.; Siddiqui, Adnan H.

    2014-01-01

    The worldwide prevalence of intracranial aneurysms is estimated to be between 5% and 10%, with some demographic variance. Subarachnoid hemorrhage secondary to ruptured intracranial aneurysm results in devastating neurological outcomes, leaving the majority of victims dead or disabled. Surgical clipping of intracranial aneurysms remained the definitive mode of treatment until Guglielmi detachable coils were introduced in the 1990s. This revolutionary innovation led to the recognition of neurointervention/neuroendovascular surgery as a bona fide option for intracranial aneurysms. Constant evolution of endovascular devices and techniques supported by several prospective randomized trials has catapulted the endovascular treatment of intracranial aneurysms to its current status as the preferred treatment modality for most ruptured and unruptured intracranial aneurysms. We are slowly transitioning from the era of coils to the era of flow diverters. Flow-diversion technology and techniques have revolutionized the treatment of wide-necked, giant, and fusiform aneurysms, where the results of microsurgery or conventional neuroendovascular strategies have traditionally been dismal. Although the Pipeline™ Embolization Device (ev3-Covidien, Irvine, CA) is the only flow-diversion device approved by the Food and Drug Administration for use in the United States, others are commercially available in Europe and South America, including the Silk (Balt Extrusion, Montmorency, France), Flow-Redirection Endoluminal Device (FRED; MicroVention, Tustin, CA), Surpass (Stryker, Kalamazoo, MI), and p64 (Phenox, Bochum, Germany). Improvements in technology and operator experience and the encouraging results of clinical trials have led to broader acceptance for the use of these devices in cerebral aneurysm management. Continued innovation and refinement of endovascular devices and techniques will inevitably improve technical success rates, reduce procedure-related complications, and broaden

  8. Flow modifying device

    NASA Technical Reports Server (NTRS)

    Kelm, J. S.; Vickers, E. C.; Williams, J. J.; Taylor, J. R. (Inventor)

    1985-01-01

    A swirler for a gas turbine engine combustor is disclosed for simultaneously controlling combustor flow rate, swirl angle, residence time and fuel-air ratio to provide three regimes of operation. A first regime is provided in which fuel-air ratio is less than stoichiometric, NOx is produced at one level, and combustor flow rate is high. In a second regime, fuel-air ratio is nearly stoichiometric, NOx production is less than that of the first regime, and combustor flow rate is low. In a third regime, used for example at highoff, fuel-air ratio is greater than stoichiometric and the combustor flow rate is less than in either of the other regimes.

  9. 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

  10. Preservation of Internal Iliac Artery after Endovascular Repair of Common Iliac Artery Dissection Using Modified Fenestrated Stent Graft

    PubMed Central

    Zha, Binshan; Liu, Bin; Ye, Yusheng; Li, Jun

    2016-01-01

    Standard endovascular repair of iliac/aortoiliac pathologies can lead to complications, such as buttock claudication, colon ischemia and erectile dysfunction. Branch grafts have been developed but require at least 6 weeks for customization and are not currently available in China; they are also quite expensive. To our knowledge, modified fenestrated stent grafts (MFSGs) are a safe and effective alternative for treating patients with juxtarenal aneurysms. Most MFSGs are used for the preservation of renal and left subclavian arteries. Few cases of MFSGs have been reported in the treatment of iliac pathologies. The use of an MFSG is decided on a case-by-case basis. This report presents our first clinical use of an MFSG for preservation of the internal iliac artery. PMID:27275179

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

    PubMed Central

    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.

    2014-01-01

    Background and Purpose 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. Methods Sixty patients with a TICI score of 0, 1 and ICA/M1 occlusion at baseline were evaluated. A blinded reader assigned a collateral score using a prior 5 point scale, from 0 (no collateral flow) to 4 (complete/rapid collaterals to entire ischemic territory). Analysis was dichotomized to poor flow (0–2) versus good flow (3–4). Collateral score was correlated with baseline NIHSS, DWI volume, PWI volume (Tmax ≥ 6 sec), TICI reperfusion, infarct growth and mRS at day 90. Results Collateral score correlated with baseline NIHSS (p=0.002) and Tmax ≥ 6 sec volume (p=0.009). 29% 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 (mRS 0–2 at 90 days) than patients who did not reperfuse, OR 12 (95% CI, 1.6–98). There was no difference in the rate of good functional outcome following reperfusion in the 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 vs. good collaterals, p=0.06. Conclusion Collaterals correlate with baseline NIHSS, PWI volume, and good reperfusion. However, Target Mismatch patients who reperfuse, appear to have favorable outcomes at a similar rate, irrespective of the collateral score. PMID:24569816

  12. 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 Central

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

    2014-01-01

    Summary 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. PMID:25207905

  13. 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

  14. 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. PMID:22555126

  15. 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. PMID:26169778

  16. Endovascular repair of traumatic aortic injury using a modified, commercially available endograft to preserve aortic arch branches.

    PubMed

    Kawajiri, Hidetake; Oka, Katsuhiko; Sakai, Osamu; Watanabe, Taiji; Kanda, Keiichi; Yaku, Hitoshi

    2014-05-01

    A 25-year-old woman was admitted to our hospital after being involved in a high-speed motorcycle accident. Computed tomography angiography revealed a blunt traumatic aortic injury of the lesser curvature of the distal aortic arch accompanied by splintered fractures of the seventh thoracic vertebra and left clavicle. If the pseudoaneurysm had been treated with open surgical repair, then arch replacement under cardiopulmonary bypass, which was considered to be too invasive, would have been necessary. Therefore, thoracic endovascular aortic repair (TEVAR) was preferred as a first-line treatment to prevent pulmonary complications and hemorrhaging. Because the proximal landing zone for TEVAR was insufficient, we used a modified (fenestrated) commercially available endograft to preserve the branches of the aortic arch. Postoperative computed tomography scans confirmed that the pseudoaneurysm had been excluded without the endoleaks, and the aortic arch branches were patent. The patient's postoperative course was uneventful, and she was discharged from the hospital to have surgery for a vertebral fracture on postoperative day 6. PMID:24184496

  17. 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.

  18. 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

  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. Aortic aneurysm repair - endovascular

    MedlinePlus

    EVAR; 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. ...

  1. Rapid in vitro biocompatibility assay of endovascular stents by flow cytometry using platelet activation and platelet-leukocyte aggregation.

    PubMed

    Tárnok, A; Mahnke, A; Müller, M; Zotz, R J

    1999-02-15

    Clinical studies suggest that stent design and surface texture are responsible for differences in biocompatibility of metallic endovascular stents. A simple in vitro experimental setup was established to test stent-induced degree of platelet and leukocyte activation and platelet-leukocyte aggregation by flow cytometry. Heparin-coated tantalum stents and gold-coated and uncoated stainless steel stents were tested. Stents were implanted into silicone tubes and exposed to blood from healthy volunteers. Platelet and leukocyte activation and percentage of leukocyte-platelet aggregates were determined in a whole-blood assay by subsequent staining for activation-associated antigens (CD41a, CD42b, CD62p, and fibrinogen binding) and leukocyte antigens (CD14 and CD45) and flow cytometric analysis. Blood taken directly after venous puncture or exposed to the silicone tube alone was used as negative controls. Positive control was in vitro stimulation with thrombin receptor activating peptide (TRAP-6). Low degree of platelet activation and significant increase in monocyte- and neutrophil-platelet aggregation were observed in blood exposed to stents (P < 0.05). In addition, leukocyte activation was induced as measured by increased CD45 and CD14 expression. Heparin coated stents continuously induced less platelet activation and leukocyte-platelet aggregation than uncoated stainless steel stents of the same length and shorter stents of the same structure. Stent surface coating and texture plays a role in platelet and leukocyte activation and leukocyte-platelet aggregation. Using this simple in vitro assay and whole blood and flow cytometry, it seems possible to differentiate stents by their potency to activate platelets and/or leukocytes. This assay could be applied for improving the biocompatibility of coronary stents. PMID:10088974

  2. 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

  3. 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.

  4. 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

  5. Aortic aneurysm repair - endovascular- discharge

    MedlinePlus

    ... page: //medlineplus.gov/ency/patientinstructions/000236.htm Aortic aneurysm repair - endovascular - discharge To use the sharing features ... enable JavaScript. AAA repair - endovascular - discharge; Repair - aortic aneurysm - endovascular - discharge; EVAR - discharge; Endovascular aneurysm repair - discharge ...

  6. Endovascular management of renal artery aneurysms using the multilayer flow modulator

    PubMed Central

    Sultan, Sherif; Basuoniy Alawy, Mahmoud; Flaherty, Rita; Kavanagh, Edel P; Elsherif, Mohamed; Elhelali, Ala; Stefanov, Florian; Lundon, Violet; Hynes, Niamh

    2016-01-01

    Objective Our aim was to describe our experience of the Multilayer Flow Modulator (MFM, Cardiatis, Isnes, Belgium) used in the treatment of type III renal artery aneurysms (RAA). Methods This is a single-centre study. 3 patients (2 men and 1 woman; mean age 59 years; range 41–77 years) underwent treatment of a type III renal artery aneurysm using the MFM. The indications were a 23.9 mm type III RAA at the bifurcation of the upper and lower pole vessels, with 4 side branches; a 42.4 mm type III saccular RAA at the renal hilum; and a 23 mm type III RAA at the origin of the artery, supplying the upper pole. Results Patients had a mean follow-up of 27 months, and were assessed by perioperative renal function tests, and repeat postoperative CT scan. There were no immediate postoperative complications or mortality. The first patient's aneurysm shrank by 8.6 mm, from 23.9 to 15.3 mm over 19 months, with all 4 side branches remaining patent. The largest aneurysm at 42.4 mm completely thrombosed, while the renal artery remained patent to the kidney. The final patient refused to have any follow-up scans but had no deterioration in renal function below 30 mL/min, and no further symptoms reported. Conclusions The MFM is safe and effective in the management of patients with complex renal artery aneurysms. The MFM can be used to treat branched or distal renal artery aneurysms with exclusion of the aneurysm from the circulation, while successfully preserving the flow to the side branches and kidney. Initial results are promising, however, longer follow-up and a larger cohort are required to prove the effectiveness of this emerging technology. PMID:27042315

  7. 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. PMID:25426330

  8. 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

  9. 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.

  10. 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.

  11. Endovascular treatment of intracranial aneurysms.

    PubMed

    Diaz, Orlando; Rangel-Castilla, Leonardo

    2016-01-01

    Intracranial aneurysms are abnormal dilations of the intracranial vessels, in which all the layers of the vascular wall are affected by degenerative changes that lead to distension of the vessel. Intracranial aneurysms can be classified based on their anatomic location, size, and morphology. Subarachnoid hemorrhage is the most devastating clinical presentation. The goal of preventing hemorrhage or rehemorrhage can only be achieved by excluding the aneurysm from the cerebral circulation. Endovascular or surgical clipping can achieve this goal. Multiple surgical and endovascular approaches have been described for treatment of intracranial aneurysm. Surgical approaches for anterior-circulation intracranial aneurysms include: pterional, orbitozygomatic, and lateral supraorbital craniotomies. Modern microsurgical techniques involve skull base dissection to achieve adequate exposure with minimal brain retraction. Endovascular techniques can be divided into: parent artery reconstruction with coil deposition (primary coil, balloon-assisted coiling, stent-assisted coiling, and other new techniques such as neck reconstruction devices and intraluminal occlusion devices); reconstruction with flow diversion; and deconstructive techniques with involving parent artery sacrifice with or without bypass. PMID:27430470

  12. A new stent with streamlined cross-section can suppress monocyte cell adhesion in the flow disturbance zones of the endovascular stent.

    PubMed

    Chen, Zengsheng; Zhan, Fan; Ding, Jun; Zhang, Xiwen; Deng, Xiaoyan

    2016-01-01

    We proposed a new stent with streamlined cross-sectional wires, which is different from the clinical coronary stents with square or round cross-sections. We believe the new stent might have better hemodynamic performance than the clinical metal stents. To test the hypothesis, we designed an experimental study to compare the performance of the new stent with the clinical stents in terms of monocyte (U-937 cells) adhesion. The results showed that when compared with the clinical stents, the adhesion of U-937 cells were much less in the new stent. The results also showed that, when Reynolds number increased from 180 (the rest condition for the coronary arteries) to 360 (the strenuous exercise condition for the coronary arteries), the flow disturbance zones in the clinical stents became larger, while they became smaller with the new stent. The present experimental study therefore suggests that the optimization of the cross-sectional shape of stent wires ought to be taken into consideration in the design of endovascular stents. PMID:25434694

  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. Assessment of hand blood flow: A modified technique

    SciTech Connect

    Kirsh, J.C.; Tepperman, P.S.

    1985-05-01

    Radionuclide blood flow studies are frequently used in conjunction with static bone imaging of the hands to obtain valuable information regarding relative vascularity. This study was undertaken to demonstrate; a significant blood flow artefact with the conventional bolus injection technique (Tc-99m MDP) used in dynamic hand imaging, and a modified technique which virtually eliminates this artefact. The artefact is presumably due to reactive hyperemia induced by the tourniquet used to occlude venous return prior to injection. A modified technique was developed using intermittent injections of saline via a butterfly needle to maintain venous patency. This allows time for the reflex hyperemia to return to the basal state before injecting the radiopharmaceutical. Only 1 of 23 additional subject (4%) demonstrated significant artefactual asymmetry with the modified technique. A highly significant different (rho < .001) was observed between the two techniques. Additionally, there was no significant difference (rho = .50) between the observed pattern with the modified technique and the expected normal symmetrical pattern. Therefore, use of this technique will eliminate a potentially seriously misleading artefact.

  15. 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.

  16. 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

  17. 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

  18. 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.

  19. Endovascular Treatment of Venous Occlusive Disease

    PubMed Central

    2008-01-01

    Endovascular treatment of acute and chronic iliac vein occlusions has proven to be safe and effective. Recanalization of chronic occlusions with balloon angioplasty and stenting can re-establish normal venous flow in the iliac veins and the IVC and relieve symptoms in the majority of treated patients. CDT with recanalization and stenting of underlying chronically obstructed iliofemoral segments is becoming the treatment of choice for patients with acute iliofemoral thrombosis, as anticoagulation and compression therapy alone are not satisfactory in preventing PTS. The new treatment modalities offer stimulating options for a patient group that is not adequately treated, neither by medical nor open surgical therapy. The substantial effort and additional costs of endovascular treatment appear to be justified by the encouraging mid-term results both for patients with acute and chronic occlusive iliofemoral disease. However, multi-center randomized prospective studies are required to further validate the role of these techniques. PMID:23555345

  20. 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

  1. [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. PMID:26035580

  2. Endovascular Intervention in the Treatment of Peripheral Artery Disease.

    PubMed

    Couto, Marian; Figueróa, Alejandro; Sotolongo, Antonio; Pérez, Reynerio; Ojeda, José Martinez

    2015-01-01

    Endovascular therapy has emerged as an essential part of the management we can offer patients suffering from peripheral arterial disease. The AHA/ACCF guidelines deemed ballon angioplasty as a reasonable alternative for patients with limb threatening lower extremity ischemia who are not candidates for an autologus venous graft. Endovascular treatment is most useful for the treatment of critical limb ischemia and should ensure adequate proximal flow before engaging in interventions of distal disease.To increase procedure success rate, a thorough diagnostic evaluation is fundamental. This evaluation must take into account amount of calcium, no flow occlusion, length of occlusion, and presence of collaterals. There are different tools and procedure techniques available. Among these are the medicated ballon angioplasty and atherectomy by laser or high-speed drill, among others. Further studies may consolidate endovascular intervention as a safe and effective management for patients with lower extremity arterial disease and possibly cause a change in the actual practice guidelines. PMID:26742196

  3. Endovascular reconstruction of aneurysms with a complex geometry.

    PubMed

    Gupta, Vipul; Parthasarathy, Rajsrinivas; Jha, Ajaya Nand

    2016-01-01

    Conventional endovascular coiling remains the mainstay of treatment for most aneurysms; however, it may not be suitable for aneurysms with a complex geometry and there remains the risk of recanalization. Aneurysms with an unfavorable morphology are difficult to treat through both endovascular and surgical means. Progress in endovascular technology has allowed for the emergence of newer strategies to treat aneurysms with a complex geometry. Better packing density in wide-necked and large aneurysms can be achieved through the balloon remodeling technique. Similarly, a self-expanding stent cannot only act as a scaffold that helps to retain coils but also aids in diverting the blood flow away from the aneurysm sac. Lately, focus has shifted from endosaccular occlusion to endoluminal reconstruction; flow diverters are being increasingly used to treat aneurysms with an unfavorable geometry. However, there is no clear consensus on the best endovascular management strategy in certain subset of aneurysms - large and giant internal carotid aneurysms, blister aneurysms, and fusiform/dissecting aneurysms of the vertebrobasilar artery. We present a review of literature and discuss the current evidence for the various endovascular strategies to treat complex aneurysms. PMID:26954964

  4. 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.

  5. 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

  6. Magnetic Resonance-Guided Passive Catheter Tracking for Endovascular Therapy.

    PubMed

    Settecase, Fabio; Martin, Alastair J; Lillaney, Prasheel; Losey, Aaron; Hetts, Steven W

    2015-11-01

    The use of MR guidance for endovascular intervention is appealing because of 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, and cardiac motion. This review highlights state-of-the-art imaging techniques and hardware used for passive tracking of endovascular devices in interventional MR imaging, including negative contrast, passive contrast, nonproton multispectral, and direct current techniques. The advantages and disadvantages of passive tracking relative to active tracking are also summarized. PMID:26499277

  7. 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.

  8. Emergency endovascular revascularization of tandem occlusions: Internal carotid artery dissection and intracranial large artery embolism.

    PubMed

    Cohen, José E; Leker, Ronen R; Eichel, Roni; Gomori, Moshe; Itshayek, Eyal

    2016-06-01

    Internal carotid artery dissection (ICAD) with concomitant occlusive intracranial large artery emboli is an infrequent cause of acute stroke, with poor response to intravenous thrombolysis. Reports on the management of this entity are limited. We present our recent experience in the endovascular management of occlusive ICAD and major intracranial occlusion. Consecutive anterior circulation acute stroke patients meeting Medical Center criteria for endovascular management of ICAD from June 2011 to June 2015 were included. Clinical, imaging, and procedure data were collected retrospectively under Institutional Review Board approval. The endovascular procedure for carotid artery revascularization and intracranial stent thrombectomy is described. Six patients met inclusion criteria (National Institutes of Health Stroke Scale score 12-24, time from symptom onset 2-8hours). Revascularization of the extracranial carotid dissection and stent thrombectomy were achieved in 5/6 patients, resulting in complete recanalization (Thrombolysis in Myocardial Infarction flow grade 3 in a mean 2.7hours), and modified Rankin Scale score 0-2 at 90 day follow-up. In one patient, attempts to microcatheterize the true arterial lumen failed and thrombectomy was therefore not feasible. No arterial dissection, arterial rupture or accidental stent detachment occurred, and there was no intracerebral hemorrhage or hemorrhagic transformation. Our preliminary data on this selected subgroup of patients suggest the presented approach is safe, feasible in a significant proportion of patients, and efficacious in achieving arterial recanalization and improving patient outcome. Crossing the dissected segment remains the most important limiting factor in achieving successful ICA recanalization. Further evaluation in larger series is warranted. PMID:26924182

  9. Imaging equipment and techniques for optimal intraoperative imaging during endovascular interventions.

    PubMed

    Fillinger, M F; Weaver, J B

    1999-12-01

    Because endovascular procedures represent an ever-increasing portion of many vascular surgery practices, many surgeons are faced with difficult choices. Endovascular procedures often require open surgery, and open surgical techniques increasingly require fluoroscopic imaging. Without good intraoperative imaging, endovascular procedures are difficult and endovascular aneurysm repair is impossible. How does one balance the need for optimal imaging without sacrificing the ability to safely perform open surgical procedures, especially in the early stages of a developing endovascular program? Strategies include the use of a portable c-arm and carbon fiber table in the operating room (OR), adding a fixed imaging platform to an OR, gaining access to an angiography suite that does not meet OR requirements, and modifying it into an interventional suite that does meet operating room standards. Once the optimal equipment and facilities have been chosen, other choices must be considered. Should a radiology technician be hired? Should an interventional radiologist be available to assist or be incorporated as a routine member of the team? How will typical operating room procedures and technique need to be altered in an effort to optimize intraoperative imaging for endovascular procedures? This article gives an overview of the many issues that arise as a vascular surgery practice evolves to incorporate complex endovascular procedures. PMID:10651460

  10. Towards an entirely endovascular aortic world: an update of techniques and outcomes for endovascular and open treatment of type I, II, and III endoleaks.

    PubMed

    Mangialardi, Nicola; Orrico, Matteo; Ronchey, Sonia; Praquin, Barbara; Alberti, Vittorio; Setacci, Carlo

    2016-10-01

    Endovascular aneurysm repair (EVAR) is largely the most adopted strategy for aneurysmal disease of the aorta. Nevertheless, the high incidence of reintervention makes it difficult to identify EVAR as a definitive solution; in particular, the most frequent indication of reintervention is endoleak, which is defined as persistent flow into the aneurysmal sac from different sources. Several treatment strategies are described. A contemporary literature search was performed with the intent of describing techniques and outcomes of endovascular and open strategies to type I, II, and III endoleak. Described techniques and outcomes were organized by indication (type I, II, and III endoleak) and by type of approach (endovascular, open, and laparoscopic) to give an overview of the current status of the treatment for the three most frequent types of endoleak. Several endovascular means are described in the literature for the treatment of endoleak. PMID:27465391

  11. 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

  12. 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. PMID:27401813

  13. 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.

  14. Endovascular approach to Leriche syndrome.

    PubMed

    Setacci, C; Galzerano, G; Setacci, F; De Donato, G; Sirignano, P; Kamargianni, V; Cannizzaro, A; Cappelli, A

    2012-06-01

    The chronic obstruction of the aortic bifurcation and iliac axis was definide by the French surgeon Rene Leriche, whose name it bears today. The advancing age of the population move the definition from a syndrome, as reported from Leriche, to complex aortoiliac vascular lesions current multidisciplinary guidelines recommend to treat extensive aortoiliac occlusive disease by surgical revascularization. Surgery provides good long-term patency, but at the cost of substantial perioperative morbidity. Development of new technologies and techniques has led to increased use of endovascular therapy for extensive aortoiliac disease. This review article summarized current multidisciplinary guidelines indication in endovascular treatment of extensive aorto-iliac disease and the various worldwide single centre experience published on endovascular treatment of Leriche Syndrome. PMID:22695262

  15. 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.

  16. 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. PMID:26296255

  17. A modified NaSch model with density-dependent randomization for traffic flow

    NASA Astrophysics Data System (ADS)

    Zhu, H. B.; Ge, H. X.; Dong, L. Y.; Dai, S. Q.

    2007-05-01

    Based on the Nagel-Schreckenberg (NaSch) model of traffic flow, a modified cellular automaton (CA) traffic model with the density-dependent randomization (abbreviated as the DDR model) is proposed to simulate traffic flow. The fundamental diagram obtained by simulation shows the ability of this modified NaSch model to capture the essential features of traffic flow, e.g., synchronized flow, metastable state, hysteresis and phase separation at higher densities. Comparisons are made between this DDR model and the NaSch model, also between this DDR model and the VDR model. And the underlying mechanism is analyzed. All these results indicate that the presented model is reasonable and more realistic.

  18. A modified Darcy's law . Large eddy simulation of turbulent flows through a fractal model city

    NASA Astrophysics Data System (ADS)

    Gisinger, Sonja; Dörnbrack, Andreas; Schröttle, Josef

    2015-08-01

    An approach to describe the turbulent flow through a complex geometry (e.g., urban area) by means of an analogy to flows through porous media is presented. Therefore, a modification of the original Darcy's law is proposed, and its application is tested in a prototype problem with an idealized complex geometry using large eddy simulations. The numerical results indicate the validity of the modified Darcy's law for the chosen setup.

  19. 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

  20. Listeria monocytogenes Endovascular Graft Infection

    PubMed Central

    Heysell, Scott K.; Hughes, Molly A.

    2016-01-01

    Although best managed by surgical resection, we present a case of Listeria monocytogenes endovascular graft infection alternatively treated with graft retention and antibiotic induction followed by a lifelong suppressive course. The epidemiological, pathological, and clinical features of this unique entity are reviewed. PMID:26835477

  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. 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. PMID:26747681

  3. 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.

  4. 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. PMID:25864045

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

    PubMed

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

    2014-01-01

    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. PMID:25131175

  6. Endovascular treatment of posterior condylar canal dural arteriovenous fistula.

    PubMed

    Maus, Volker; Söderman, Michael; Rodesch, Georges; Kabbasch, Christoph; Mpotsaris, Anastasios

    2016-01-01

    Posterior condylar canal dural arteriovenous fistulas (PCC DAVFs) are rare lesions that may present with pulse-synchronous bruit. In cases with venous reflux there is a risk of haemorrhage or even dementia. Diagnosis and endovascular treatment require a profound knowledge of the vascular anatomy of the craniocervical junction and comprehensive neurovascular imaging. We describe the clinical presentation, angiographic imaging and endovascular treatment of a PCC DAVF in a female patient with pulse-synchronous bruit as the presenting symptom. The fistula drained almost exclusively into the sigmoid sinus and internal jugular vein. There was no intracranial reflux. The PCC DAVF was treated with transvenous coil occlusion of the fistulous pouch in the condylar canal. Symptoms resolved immediately after intervention and the patient recovered quickly without any neurological deficits. MR angiography confirmed occlusion of the DAVF. The dural sinus was patent with normal blood flow. PMID:27247204

  7. 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. PMID:27175464

  8. Endovascular treatment of popliteal aneurysm.

    PubMed

    de Donato, G; Setacci, F; Galzerano, G; Borrelli, M P; Mascolo, V; Mazzitelli, G; Ruzzi, U; Setacci, C

    2015-08-01

    Although traditional surgical repair by aneurysm exclusion and bypass is still considered the gold standard in the treatment of popliteal artery aneurysms (PAAs), the endovascular repair (ER) has been gaining great interest in the last decades. ER offers several advantages over open bypass, including lower morbidity and mortality, and faster functional recovery, but some concerns about migration, occlusion, or fracture remain when a stent graft is deployed across a joint that undergo constant flexion. This review summarizes the current evidence on ER for PAAs. Level I evidence is still very limited, while the majority of published data come from retrospective studies. Moreover the heterogeneity of PAA morphology seems to play a major role in the outcomes after popliteal endografts placement, so that many anatomical criteria should be taken into account to determine which patient is best treated endovascularly. In conclusion, while it is unlike that endovascular treatment may displace open surgical bypass in the near future, it indeed does provide a feasible option for selected patients with high surgical risk and good anatomical features. PMID:25742934

  9. Assessing Skin Blood Flow Dynamics in Older Adults Using a Modified Sample Entropy Approach

    PubMed Central

    Liao, Fuyuan; Jan, Yih-Kuen

    2015-01-01

    The aging process may result in attenuated microvascular reactivity in response to environmental stimuli, which can be evaluated by analyzing skin blood flow (SBF) signals. Among various methods for analyzing physiological signals, sample entropy (SE) is commonly used to quantify the degree of regularity of time series. However, we found that for temporally correlated data, SE value depends on the sampling rate. When data are oversampled, SE may give misleading results. To address this problem, we propose to modify the definition of SE by using time-lagged vectors in the calculation of the conditional probability that any two vectors of successive data points are within a tolerance r for m points remain within the tolerance at the next point. The lag could be chosen as the first minimum of the auto mutual information function. We tested the performance of modified SE using simulated signals and SBF data. The results showed that modified SE is able to quantify the degree of regularity of the signals regardless of sampling rate. Using this approach, we observed a more regular behavior of blood flow oscillations (BFO) during local heating-induced maximal vasodilation period compared to the baseline in young and older adults and a more regular behavior of BFO in older adults compared to young adults. These results suggest that modified SE may be useful in the study of SBF dynamics. PMID:25570060

  10. Newer endovascular tools: a review of experimental and clinical aspects.

    PubMed

    Sorenson, Thomas; Brinjikji, Waleed; Lanzino, Giuseppe

    2016-03-01

    The history of treatment of intracranial aneurysms dates back to the late 18th century. These early physicians largely based their crude techniques around "wire insertion alone, galvanopuncture (electrothrombosis), and fili-galvanopuncture (wire insertion together with electrothrombosis)," albeit with overwhelmingly unfavorable outcomes. By the end of the 20th century, treatment options progressed to include two highly effective, and safe, procedures: surgical clipping and endovascular coiling. These methods have been found to be effective treatments for a large portion of aneurysms, but there still exists a subset of patients that do not respond well to these therapies. While much progress has been made in stent-assisted coiling including the development of newer stents aimed at keep the coil ball from protruding into the parent vessel, the introduction of flow diverters has characterized a new phase in the endovascular treatment of intracranial aneurysms. This treatment paradigm is rapidly becoming the treatment of choice for large and complex aneurysms internal carotid artery. Intrasaccular flow diverters such as the Woven EndoBridge device (WEB) and Luna device are showing promise in the treatment of wide neck bifurcation aneurysms. Other newer devices including the pCONus Bifurcating Aneurysm Implant and Endovascular Clip Systems (eCLIPs) are showing promise in small clinical and preclinical studies. As technology improves, newer devices with ingenious designs are constantly being introduced into the clinical arena. Most of these devices try to address the limitations of traditional endovascular methods in regard to providing a safe and effective treatment of wide-necked bifurcation aneurysms. Several large prospective studies are underway and once completed, the role of these newer devices will be better defined. It is easy to anticipate that with advances in 3D techniques and printing, a future in which customized devices are designed based on the individual

  11. Developing a complex endovascular fenestrated and branched aortic program.

    PubMed

    Schanzer, Andres; Baril, Donald; Robinson, William P; Simons, Jessica P; Aiello, Francesco A; Messina, Louis M

    2015-03-01

    In 2008, the top priority in our division's 5-year strategic plan was "to become an internationally recognized center of excellence for the endovascular treatment of complex aortic pathology extending from the aortic valve to the external iliac artery." Five components were identified as "most critical" to achieve this strategic priority: (1) training at centers of excellence in complex endovascular repair; (2) industry partnership to improve access to developing technologies; (3) a fully integrated team approach with one leader involved in all steps of all cases; (4) prospective data collection; and (5) development and implementation of a physician-sponsored investigational device exemption for juxtarenal, pararenal, and thoracoabdominal aneurysms. We have now performed 49 repairs (16 commercially manufactured devices, 33 physician-modified devices) for 3 common iliac, 20 juxtarenal, 9 pararenal, and 17 thoracoabdominal aneurysms, using 142 fenestrations, branches, and scallops. All patients had complete 30-day follow-up for calculation of 30-day events. Kaplan-Meier analysis was used to calculate 1-year events. In 5 years, we developed a successful complex endovascular aortic program that uses fenestrated/branched repair techniques. A focused team strategic planning approach to program development is an effective way for vascular surgery divisions to gain experience and expertise with new complex technologies while ensuring acceptable patient outcomes. PMID:25595400

  12. 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.

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

    NASA Astrophysics Data System (ADS)

    Scanlon, Todd M.; Raffensperger, Jeff P.; Hornberger, George M.; Clapp, Roger B.

    2000-09-01

    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.

  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. 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.

  17. Regional blood flows measured in Mongolian gerbil by a modified microsphere method.

    PubMed

    Matsumoto, M; Kimura, K; Fujisawa, A; Matsuyama, T; Asai, T; Uyama, O; Yoneda, S; Abe, H

    1982-06-01

    Regional blood flow to major organs and regional cerebral blood flow were determined in seven anesthetized male gerbils by a modified microsphere method. Carbonized microspheres, 15 micrometers in diameter and labeled with 85Sr or 141Ce, were injected into the left ventricle by cardiac puncture through the closed thorax, and reference samples of known volume were withdrawn from tail-artery cannula. No significant hemodynamic alterations were observed during microsphere administration, and extraction of 15-micrometers microspheres by the pulmonary or systemic capillary beds was nearly 100%. The adequacy of mixing of microspheres in the left ventricle was also validated. The absolute regional blood flow to various organs and regional cerebral blood flow were expressed in terms of milliliters per minute per gram tissue weight, and the values mostly agreed with those reported previously in rats. The results indicate that the reference sample method can be applied to the gerbil. This method should allow the gerbil, which is an animal widely used in stroke research, to be conveniently used for hemodynamic studies when organ blood flow and regional cerebral blood flow are necessary. PMID:7091359

  18. 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. PMID:25839120

  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. 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

  1. Cerebrovascular neurosurgery in evolution: the endovascular paradigm.

    PubMed

    Sorkin, Grant C; Dumont, Travis M; Eller, Jorge L; Mokin, Maxim; Snyder, Kenneth V; Levy, Elad I; Siddiqui, Adnan H; Hopkins, L Nelson

    2014-02-01

    Endovascular technique represents an important, minimally invasive approach to treating cerebrovascular disease. In this article, we discuss the origins of endovascular neurosurgery as a discipline in the context of important technical milestones, evidence-based medicine, and future cerebrovascular neurosurgical training. Cerebrovascular neurosurgery has seen a steady, convergent evolution toward the surgeon capable of seamless incorporation of open and endovascular approaches to any complex vascular disease affecting the central nervous system. Neurosurgery must assume the leadership role in the multidisciplinary neurovascular team. PMID:24402487

  2. 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.

  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. PMID:27430469

  4. 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. PMID:22817944

  5. 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. PMID:26914326

  6. Endovascular optical coherence tomography intensity kurtosis: visualization of vasa vasorum in porcine carotid artery

    PubMed Central

    Cheng, Kyle H. Y.; Sun, Cuiru; Vuong, Barry; Lee, Kenneth K. C.; Mariampillai, Adrian; Marotta, Thomas R.; Spears, Julian; Montanera, Walter J.; Herman, Peter. R.; Kiehl, Tim-Rasmus; Standish, Beau A.; Yang, Victor X. D.

    2012-01-01

    Application of speckle variance optical coherence tomography (OCT) to endovascular imaging faces difficulty of extensive motion artifacts inherently associated with arterial pulsations in addition to other physiological movements. In this study, we employed a technique involving a fourth order statistical method, kurtosis, operating on the endovascular OCT intensity images to visualize the vasa vasorum of carotid artery in vivo and identify its flow dynamic in a porcine model. The intensity kurtosis technique can distinguish vasa vasorum from the surrounding tissues in the presence of extensive time varying noises and dynamic motions of the arterial wall. Imaging of vasa vasorum and its proliferation, may compliment the growing knowledge of structural endovascular OCT in assessment and treatment of atherosclerosis in coronary and carotid arteries. PMID:22435088

  7. Preservation of pelvic circulation in one-stage endovascular repair of bilateral hypogastric artery aneurysms.

    PubMed

    Christos, Karathanos; Dimitrios, Xanthopoulos; Elias, Kaperonis; Theophanis, Konstantopoulos; Maria, Exarchou; Vasilios, Papavassiliou

    2014-10-01

    Bilateral hypogastric artery aneurysms (HAAs) are relatively rare conditions that pose increased management difficulties. We report a case of one-stage endovascular repair of bilateral HAAs preserving pelvic circulation. A 67-year-old asymptomatic man with bilateral HAAs (4-cm right and 3.9-cm left) was successfully treated with an endovascular approach. The aneurysmal sac of the right hypogastric artery (HA) was embolized first and 2 covered stent grafts were deployed into the HA. Coil embolization of the left HAA was then performed followed by deployment of a covered stent graft to the common and external iliac arteries. Final angiography revealed complete exclusion of the aneurysms without endoleaks and with preservation of the pelvic flow. At the 18-month follow-up, the patient remained asymptomatic with good patency of the stent grafts. This case demonstrates an alternative endovascular approach for the treatment of bilateral HAAs that minimizes the risk of ischemic complications by preserving pelvic circulation. PMID:24858586

  8. 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 ...

  9. 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

  10. A modified fluorescent microsphere-based approach for determining resting and hyperemic blood flows in individual murine skeletal muscles

    PubMed Central

    Cardinal, Trevor R.; Hoying, James B.

    2007-01-01

    The goal of this study was to develop a modified fluorescent microsphere-based approach for measuring resting and hyperemic blood flows in individual mouse skeletal muscles. Absolute resting blood flow in the left gracilis posterior was 1.04±0.12 ml·min−1·g−1, while functional hyperemia following muscle activity was 5.94±1.33 ml·min−1·g−1. Measuring absolute blood flow requires sampling arterial blood that serves as a flow-rate and concentration reference to the fluorescent microsphere (FMS) content in the tissue-of-interest for calculating the flow value. Because sampling arterial blood can impair cardiovascular function in the mouse, we also modified our FMS approach to determine relative blood flows in the left gracilis posterior by using the contralateral muscle as our reference in blood flow calculations. Absolute and relative hyperemia measurements detect similar increases in blood flow — 521.93±216.76% and 555.24±213.82%, respectively. However, sampling arterial blood during absolute blood flow measurements significantly decreased mean arterial pressure from the beginning to the end of our experiments, from 102.7±2.18 to 75.5±9.71 mm Hg. This decrease was not seen when measuring relative blood flows. This approach provides critical advantages over contemporary blood flow measurement approaches by allowing blood flow measurements in small and non-superficial tissues. PMID:17500044

  11. 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

  12. Percutaneous endovascular stents: an experimental evaluation.

    PubMed

    Wright, K C; Wallace, S; Charnsangavej, C; Carrasco, C H; Gianturco, C

    1985-07-01

    Percutaneous, expanding, endovascular stents were constructed of stainless steel wire formed in a zig-zag pattern. Stents were placed for varying periods of time in the jugular vein, vena cava, and abdominal aorta in each of five adult dogs. The dilating force of the stents could be controlled by different wire size, number and angle of wire bends, and stent length. In addition, multiple stents could be placed one inside the other or one after the other, depending on the circumstance. The stents distended the vessels and increased their diameter. No flow defects, luminal narrowing, or occlusion were noted in any of the stented vessels, even after 6 months. Side branches bridged by the stents remained patent and showed no indication of narrowing. Stent wires became encased by a proliferation of the tunica intima where they contacted the vessel wall. Encasement was slower and less extensive in the abdominal aorta. No vascular erosion or clot formation was found to be associated with any of the stents. PMID:4001423

  13. Tensile flow and work-hardening behavior of a Ti-modified austenitic stainless steel

    SciTech Connect

    Sivaprasad, P.V.; Venugopal, S.; Venkadesan, S.

    1997-01-01

    The flow-stress data of a 15Cr-15Ni-2.2Mo-Ti modified austenitic stainless steel in the temperature range 300 to 1,023 K was analyzed in terms of Ludwigson and Voce equations. The parameters of these equations were critically examined with respect to the effect of Ti/C ratio and test temperature. It was found that the Ludwigson equation described the flow behavior adequately up to the test temperature of 923 K, whereas the Voce equation could be employed in the full temperature range. The peaks/plateaus observed in the variation of these parameters as a function of temperature in the intermediate temperature range have been identified as one of the manifestations of dynamic strain aging (DSA). Also, the variation of these parameters with temperature clearly could bring out the different domains of DSA observed in this alloy. The work-hardening analysis of the flow-stress data revealed that in the DSA regime, the onset of stage III hardening is athermal.

  14. 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.

  15. 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. PMID:25461928

  16. 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).

  17. 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.

  18. 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. PMID:27063713

  19. 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.

  20. Thoracic Endovascular Stent Graft Repair of Middle Aortic Syndrome.

    PubMed

    Kim, Joung Taek; Lee, Mina; Kim, Young Sam; Yoon, Yong Han; Baek, Wan Ki

    2016-09-01

    Middle aortic syndrome is a rare disease defined as a segmental narrowing of the distal descending thoracic or abdominal aorta. A thoracoabdominal bypass or endovascular treatment is the choice of treatment. Endovascular therapy consists of a balloon dilatation and stent implantation. Recently, thoracic endovascular aortic repair has been widely used in a variety of aortic diseases. We report a case of middle aortic syndrome treated with a thoracic endovascular stent graft. PMID:27549552

  1. 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

  2. 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

  3. Analysis of dynamic nonlinearity of flow control loop through modified relay test probing

    NASA Astrophysics Data System (ADS)

    Boiko, I.; Sayedain, S.

    2010-12-01

    Most of the controller tuning methods in process control are based on linear models. Through the development of a detail model of the actuator-pneumatic valve dynamics, we show that even if the static characteristic of the valve is linear (including possible linearity of the flow dependence on the valve opening) the actuator-valve dynamics are strongly nonlinear. Therefore, tuning of the flow loop will be affected by the selection of the operating point and the amplitude of the relay in the relay feedback test (RFT) or modifications of this test. It is shown that Lyapunov linearisation around an equilibrium point fails to provide a local linear model of the system, and modified RFT probing is used for investigation of the system dynamics. The same test is used for the proportional-integral controller tuning in various operating points. It is recommended that the difference in the dynamic response of the loop for different relay amplitudes and operating points should be accounted for by larger stability margins.

  4. Endograft collapse following endovascular repair of traumatic aortic injury.

    PubMed

    Annamalai, Ganesan; Cook, Richard; Martin, Michael

    2011-03-01

    The advent of endovascular treatment of traumatic thoracic aortic injuries offers a valuable, minimally invasive alternative to open surgical repair. However, there are limitations of the current endovascular stent graft technology for this group of patients. After endovascular repair meticulous follow-up is required with a high index of suspicion for potential complications including the lethal complication of endograft collapse. PMID:19784919

  5. Microembolism after Endovascular Treatment of Unruptured Cerebral Aneurysms: Reduction of its Incidence by Microcatheter Lumen Aspiration

    PubMed Central

    Kim, Dae Yoon; Park, Jung Cheol; Kim, Jae Kyun; Sung, Yu Sub; Park, Eun Suk; Kwak, Jae Hyuk; Choi, Choong-Gon

    2015-01-01

    Purpose Diffusion-weighted MR images (DWI) obtained after endovascular treatment of cerebral aneurysms frequently show multiple high-signal intensity (HSI) dots. The purpose of this study was to see whether we could reduce their incidence after embolization of unruptured cerebral aneurysms by modification of our coiling technique, which involves the deliberate aspiration of the microcatheter lumen right after delivery of each detachable coil into the aneurysm sac. Materials and Methods From January 2011 to June 2011, all 71 patients with unruptured cerebral aneurysms were treated using various endovascular methods. During the earlier period, 37 patients were treated using our conventional embolization technique (conventional period). Then 34 patients were treated with a modified coiling technique (modified period). DWI was obtained on the following day. We compared the occurrence of any DWI HSI lesions and the presence of the symptomatic lesions during the two time periods. Results The incidence of the DWI HSI lesions differed significantly at 89.2% (33/37) during the conventional period and 26.5% (9/34) during the modified period (p < 0.0001). The incidence of symptomatic lesions differed between the two periods (29.7% during the conventional period vs. 2.9% during the modified period, p < 0.003). Conclusion Aspiration of the inner content of the microcatheter right after detachable coil delivery was helpful for the reduction of the incidence of microembolisms after endovascular coil embolization for the treatment of unruptured cerebral aneurysms. PMID:26389009

  6. Flow in experimental berry aneurysms: method and model.

    PubMed

    Kerber, C W; Heilman, C B

    1983-01-01

    This study addresses two basic questions: What are the flow dynamics in aneurysms? Can these flows be modified to enhance retention of adhesive? Using Pyrex glass bifurcations, fluid flow was studied in a variety of aneurysms placed at varying positions around the bifurcations. Indicators injected into the slipstreams were recorded and studied both by stop-frame high-speed movie analysis and with 35 mm slides. Even at low-flow rates, a central slipstream strikes the apex of bifurcations, and may be partly responsible for the initial production of berry aneurysms. A low-pressure zone occurs at the lateral angle of bifurcations, probably explaining the formation of endovascular cushions. Flow into symmetrically placed narrow neck aneurysms did not occur. Indicator entered the aneurysm in a turbulent fashion only when there was orifice (lip) asymmetry. Both lip asymmetry and rapid flow favor intraaneurysmal turbulent flow. PMID:6410748

  7. Radiation exposure to anaesthetists during endovascular procedures.

    PubMed

    Arii, T; Uchino, S; Kubo, Y; Kiyama, S; Uezono, S

    2015-01-01

    Medical radiation exposure increases the likelihood of cataract formation. A personal dosimeter was attached to the left temple of 77 anaesthetists during 45 endovascular aortic aneurysm repairs and 32 interventional neuroradiology procedures. Compared with interventional neuroradiology, the median (IQR [range]) total radiation dose emitted by fluoroscopic equipment was significantly lower during endovascular aortic aneurysm repair (4175 (3127-5091 [644-9761]) mGy than interventional neuroradiology (1420 (613-2424 [165-10,840]) mGy, p < 0.001). However, radiation exposure to the anaesthetist's temple was significantly greater during endovascular aortic aneurysm repair (15 (6-41 [1-109]) μSv) than interventional neuroradiology (4 (2-8 [0-67]) μSv, p < 0.001). These data suggest that anaesthetists at our institution would have to deliver anaesthesia for ~1300 endovascular aortic aneurysm repairs and ~5000 interventional neuroradiology cases annually to exceed the general occupational limits, and ~10,000 endovascular aortic aneurysm repairs and ~37,500 interventional neuroradiology cases to exceed the ocular exposure limits recommended by the International Commission on Radiological Protection. Nevertheless, anaesthetists should be aware of the risk of ocular radiation exposure, and reduce this by limiting the time of exposure, increasing the distance from the source of radiation, and shielding. PMID:25267714

  8. Reinterventions after open and endovascular AAA repair.

    PubMed

    Malina, M

    2015-04-01

    Reinterventions seem to occur more frequently after endovascular aneurysm repair than after open surgical repair and are encountered in about 20% versus 10% of the cases, respectively. However, reinterventions following endovascular repair are predominantly endoluminal and early reinterventions are more frequent after open repair. The indications for reintervention after EVAR have changed over time. The incidence and type of reintervention depends on the complexity of the primary procedure, irrespective of whether it was open or endovascular. The use of a device outside instructions for use is associated with a higher complication rate but it may nevertheless be fully justified. Advanced stent-grafts such as fenestrated and branched devices require secondary procedures more often than a standard stent-graft. Similarly, more complex open repair, e.g. a bifurcated bypass, reimplantation of visceral arteries or a redo procedure, is also associated with more reinterventions than a simple tube graft. This manuscript presents some of the most common complications of open and endovascular aortic aneurysm repair and the reinterventions they require. Many of the complications are similar with both open and endovascular techniques. Limb thrombosis, infections and endoleaks are the most frequent indications for reintervention. PMID:25644827

  9. Treatment of fenestrated vertebrobasilar junction-related aneurysms with endovascular techniques.

    PubMed

    Zhu, De-Yuan; Fang, Yi-Bin; Wu, Yi-Na; Li, Qiang; Duan, Guo-Li; Liu, Jian-Min; Xu, Yi; Hong, Bo; Zhao, Wen-Yuan; Huang, Qing-Hai

    2016-06-01

    Fenestrated vertebrobasilar junction-related aneurysms (fVBJ-AN) are uncommon and endovascular management strategies have become the first options for the treatment of these lesions. This clinical study aimed to report our experience in the endovascular management of these lesions and to review the literature. We retrospectively reviewed 10 consecutive patients harboring 12 fVBJ-AN between January 2007 and December 2014. The demographic, angiographic and clinical data were reviewed. Additionally, a literature review was performed. Endovascular management strategies were successfully applied in all 10 patients. Post-procedural angiograms indicated total occlusion in eight (66.7%) aneurysms, a residual neck in one (8.3%) aneurysm, and three residual aneurysms (25%). No procedure-related complications were observed. Follow-up angiograms were obtained in eight patients and revealed nine occluded aneurysms and one improved aneurysm; two patients were lost to angiographic follow-up. Clinical follow-ups were obtained in all patients (until July 2015), and the modified Rankin Scale scores at 69.5months (range 17-101months) of follow-up were 0 in eight patients and 1 in two patients. Endovascular management strategies provided a high occlusion rate and an acceptable complication rate and are thus efficacious in the treatment of fVBJ-AN. Further studies are necessary to validate the utility of these treatments due to the low incidence of fVBJ-AN. PMID:26778513

  10. 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

    2016-01-01

    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. PMID:27435840

  11. Renal interventions during endovascular aneurysm repair.

    PubMed

    Davies, Mark G

    2013-12-01

    Renal insufficiency is a risk factor for mortality and morbidity during endovascular aneurysm repair. Multiple changes in practice have occurred to mitigate renal injury and renal dysfunction. Transrenal fixation does carry an increased risk of a decline in renal function in the medium term. Renal stenting for athero-occlusive disease during endovascular aneurysm repair needs careful consideration, as indications have changed and there are unexpected consequences with early vessel occlusion. The growing number of renal interventions during complex endovascular aneurysm repair with the advent of chimney snorkel/periscope techniques and the introduction of fenestrated grafts has shown the resilience of the intervention with relatively low renal issues (approximately 10%), but has also illustrated the need for additional device development. PMID:25220325

  12. 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.

  13. ZrO2-Nanoparticle-Modified Graphite Felt: Bifunctional Effects on Vanadium Flow Batteries.

    PubMed

    Zhou, Haipeng; Shen, Yi; Xi, Jingyu; Qiu, Xinping; Chen, Liquan

    2016-06-22

    To improve the electrochemical performance of graphite felt (GF) electrodes in vanadium flow batteries (VFBs), we synthesize a series of ZrO2-modified GF (ZrO2/GF) electrodes with varying ZrO2 contents via a facile immersion-precipitation approach. It is found that the uniform immobilization of ZrO2 nanoparticles on the GF not only significantly promotes the accessibility of vanadium electrolyte, but also provides more active sites for the redox reactions, thereby resulting in better electrochemical activity and reversibility toward the VO(2+)/VO2(+) and V(2+)/V(3+) redox reactions as compared with those of GF. In particular, The ZrO2/GF composite with 0.3 wt % ZrO2 displays the best electrochemical performance with voltage and energy efficiencies of 71.9% and 67.4%, respectively, which are much higher than those of 57.3% and 53.8% as obtained from the GF electrode at 200 mA cm(-2). The cycle life tests demonstrate that the ZrO2/GF electrodes exhibit outstanding stability. The ZrO2/GF-based VFB battery shows negligible activity decay after 200 cycles. PMID:27229444

  14. Assessment of urinary tract biomaterial encrustation using a modified Robbins device continuous flow model.

    PubMed

    Tunney, M M; Keane, P F; Gorman, S P

    1997-01-01

    Encrustation of biomaterials employed in the urinary tract remains a major problem resulting in obstruction or blockage of catheters and stents. Therefore, resistance to encrustation is a desirable feature of biomaterials employed in such devices. The novel assessment of biomaterial encrustation employing a continuous flow model based on a modified Robbins device is described. Artificial urine was used in conjunction with 5% CO2 to simulate the physiological environment within the upper urinary tract. The widely used urinary device biomaterials, silicone and polyurethane, were investigated in the model for hydroxyapatite and struvite encrustation. Scanning electron microscopy, energy dispersive X-ray analysis, and atomic absorption spectroscopy all showed that silicone was less prone to encrustation than polyurethane and that hydroxyapatite deposition was predominant on both surfaces. The model has the advantage that a large number of biomaterials may be investigated simultaneously because several Robbins devices may be placed in parallel. The model is recommended for comparative evaluation of biomaterial candidates for use in urinary tract devices. PMID:9178735

  15. Endovascular Repair of Thoracic Aortic Aneurysms

    PubMed Central

    Findeiss, Laura K.; Cody, Michael E.

    2011-01-01

    Degenerative aneurysms of the thoracic aorta are increasing in prevalence; open repair of descending thoracic aortic aneurysms is associated with high rates of morbidity and mortality. Repair of isolated descending thoracic aortic aneurysms using stent grafts was introduced in 1995, and in an anatomically suitable subgroup of patients with thoracic aortic aneurysm, repair with endovascular stent graft provides favorable outcomes, with decreased perioperative morbidity and mortality relative to open repair. The cornerstones of successful thoracic endovascular aneurysm repair are appropriate patient selection, thorough preprocedural planning, and cautious procedural execution, the elements of which are discussed here. PMID:22379281

  16. 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.

  17. High-Resolution Angioscopic Imaging During Endovascular Neurosurgery

    PubMed Central

    McVeigh, Patrick Z.; Sacho, Raphael; Weersink, Robert A.; Pereira, Vitor M.; Kucharczyk, Walter; Seibel, Eric J.; Wilson, Brian C.

    2014-01-01

    BACKGROUND: Endoluminal optical imaging, or angioscopy, has not seen widespread application during neurointerventional procedures, largely as a result of the poor imaging resolution of existing angioscopes. Scanning fiber endoscopes (SFEs) are a novel endoscopic platform that allows high-resolution video imaging in an ultraminiature form factor that is compatible with currently used distal access endoluminal catheters. OBJECTIVE: To test the feasibility and potential utility of high-resolution angioscopy with an SFE during common endovascular neurosurgical procedures. METHODS: A 3.7-French SFE was used in a porcine model system to image endothelial disruption, ischemic stroke and mechanical thrombectomy, aneurysm coiling, and flow-diverting stent placement. RESULTS: High-resolution, video-rate imaging was shown to be possible during all of the common procedures tested and provided information that was complementary to standard fluoroscopic imaging. SFE angioscopy was able to assess novel factors such as aneurysm base coverage fraction and side branch patency, which have previously not been possible to determine with conventional angiography. CONCLUSION: Endovascular imaging with an SFE provides important information on factors that cannot be assessed fluoroscopically and is a novel platform on which future neurointerventional techniques may be based because it allows for periprocedural inspection of the integrity of the vascular system and the deployed devices. In addition, it may be of diagnostic use for inspecting the vascular wall and postprocedure device evaluation. ABBREVIATIONS: CFB, coherent fiber bundle F, French SFE, scanning fiber endoscope PMID:24762703

  18. Surgical and Endovascular Treatment for Spinal Arteriovenous Malformations

    PubMed Central

    ENDO, Toshiki; ENDO, Hidenori; SATO, Kenichi; MATSUMOTO, Yasushi; TOMINAGA, Teiji

    2016-01-01

    Spinal arteriovenous malformation (AVM) is a broad term that constitutes diverse vascular pathologies. To date, various classification schemes for spinal AVM have been proposed in literature, which helped neurosurgeons understand the pathophysiology of the disease and determine an optimal treatment strategy. To discuss indications and results of surgical and endovascular interventions for spinal AVM, this article refers to the following classification proposed by Anson and Spetzler in 1992: type I, dural arteriovenous fistula (AVF); type II, glomus intramedullary AVM; type III, juvenile malformations; and type IV, perimedullary AVF. In general, complete obliteration of the fistula is a key for better outcome in type I dural and type IV perimedullary AVFs. On the other hand, in type II glomus and type III juvenile malformations, functional preservation, instead of pursuing angiographical cure, is the main goal of the treatment. In such cases, reduction of the shunt flow can alleviate clinical symptoms. Proper management of spinal AVM should start with neurological examination and understanding of angioarchitectures, which provide critical information that guides the indication and modality of intervention. Finally, close collaboration of the microsurgical and endovascular teams are mandatory for successful treatment. PMID:26948701

  19. 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

  20. 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

  1. Treatment of acute limb ischemia with focus on endovascular techniques.

    PubMed

    Zeller, T; Tepe, G

    2009-05-01

    Acute limb ischemia is still the most frequent cause of major limb loss. Timely and fast revascularization is the key for limb salvage and patient survival. Large randomized trials showed equivalency of surgical and endovascular revascularization by means of local lysis with urokinase (TOPAS, STILE). New lytic agents and their modified application such as via a pulse spray catheter or combined with an ultrasound catheter and the combination with glycoprotein IIb/IIIa receptor antagonists have increased the efficacy and speed of thrombolysis. Recently, mechanical thrombectomy devices have become more widespread because intervention time and bleeding complications can be reduced. This review article summarizes the clinical presentation of and the treatment options for acute arterial occlusive disease caused either by embolism or local thrombosis. PMID:19588300

  2. Imaging diagnosis and the role of endovascular embolization treatment for vascular intraspinal tumors.

    PubMed

    dos Santos, Marlise P; Zhang, Jingwen; Ghinda, Diana; Glikstein, Rafael; Agid, Ronit; Rodesch, Georges; Tampieri, Donatella; terBrugge, Karel G

    2015-08-01

    Intraspinal tumors comprise a large spectrum of neoplasms, including hemangioblastomas, paragangliomas, and meningiomas. These tumors have several common characteristic imaging features, such as highly vascular mass appearance in angiography, hypointense rim and serpentine flow voids in MRI, and intense enhancement after intravenous contrast administration. Due to their rich vascularity, these tumors represent a special challenge for surgical treatment. More recently, the surgical treatment of intraspinal vascular tumors has benefited from the combination of endovascular techniques used to better delineate these lesions and to promote preoperative reduction of volume and tissue blood flow. Endovascular embolization has been proven to be a safe procedure that facilitates the resection of these tumors; hence, it has been proposed as part of the standard of care in their management. PMID:26235014

  3. 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.

  4. Endovascular Treatment of an Aortobronchial Fistula

    SciTech Connect

    Numan, Fueruezan Arbatli, Harun; Yagan, Naci; Demirsoy, Ergun; Soenmez, Binguer

    2004-01-15

    A 67-year-old man operated on 8 years previously for type B aortic dissection presented with two episodes of massive hemoptysis. An aortobronchial fistula was suspected with spiral computed tomography angiography, and showed a small pseudoaneurysm corresponding to the distal anastomotic site. The patient underwent endovascular stent-graft implantation and is asymptomatic 8 months after the procedure.

  5. Endovascular treatment of isolated arterial pulmonary malinosculation

    PubMed Central

    Mammen, Suraj; Keshava, Shyamkumar N; Moses, Vinu; Chiramel, George Koshy; Irodi, Aparna; Gnanamuthu, Birla Roy

    2015-01-01

    We report the endovascular management of a series of four cases of isolated systemic supply to normal lung or isolated arterial pulmonary malinosculation of the left lung. In these cases, the basal segments of the left lung lacked normal pulmonary arterial supply and instead received systemic arterial blood from the descending thoracic aorta. The relevant anatomy and literature are also reviewed. PMID:26288517

  6. 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.

  7. Contrast Medium Induced Nephropathy after Endovascular Stent Graft Placement: An Examination of Its Prevalence and Risk Factors

    PubMed Central

    Kawatani, Yohei; Nakamura, Yoshitsugu; Mochida, Yoshihiko; Yamauchi, Naoya; Hayashi, Yujiro; Taneichi, Tetsuyoshi; Ito, Yujiro; Kurobe, Hirotsugu; Suda, Yuji; Hori, Takaki

    2016-01-01

    Endovascular stent graft placement has become a major treatment for thoracic and abdominal aneurysms. While endovascular therapy is less invasive than open surgery, it involves the use of a contrast medium. Contrast media can cause renal impairment, a condition termed as contrast-induced nephropathy (CIN). This study sought to evaluate the incidence and risk factors of CIN following endovascular stent graft placement for aortic aneurysm repair. The study included 167 consecutive patients who underwent endovascular stent graft placement in our hospital from October 2013 to June 2014. CIN was diagnosed using the European Society of Urogenital Radiology criteria. Patients with and without CIN were compared. Chi-squared tests, t-tests, and multivariate logistic regression analyses were performed. Thirteen patients (7.8%) developed CIN. Left ventricular dysfunction and intraoperative blood transfusion were significantly more frequent in the CIN group (P = 0.017 and P = 0.032, resp.). Multivariate analysis showed that left ventricular dysfunction had the strongest influence on CIN development (odds ratio 9.34, P = 0.018, and 95% CI = 1.46–59.7). Patients with CIN also experienced longer ICU and hospital stays. Measures to improve renal perfusion flow should be considered for patients with left ventricular dysfunction who are undergoing endovascular stent graft placement. PMID:27069685

  8. Surface charge, electroosmotic flow and DNA extension in chemically modified thermoplastic nanoslits and nanochannels.

    PubMed

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

    2015-01-01

    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

  9. 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

  10. 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. PMID:18836876

  11. 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

  12. 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. PMID:26947342

  13. 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.

  14. Spinal cord protection in aortic endovascular surgery.

    PubMed

    Scott, D A; Denton, M J

    2016-09-01

    A persistent neurological deficit, such as paraplegia or paraparesis, secondary to spinal cord injury remains one of the most feared complications of surgery on the descending thoracic or abdominal aorta. This is despite sophisticated advances in imaging and the use of less invasive endovascular procedures. Extensive fenestrated endovascular aortic graft prostheses still carry a risk of spinal cord injury of up to 10%; thus, this risk should be identified and strategies implemented to protect the spinal cord and maintain perfusion. The patients at highest risk are those undergoing extensive thoracic aortic stenting including thoracic, abdominal, and pelvic vessels. Although many techniques are available, lumbar cerebrospinal fluid drainage remains the most frequent intervention, along with maintenance of perfusion pressure and possibly staged procedures to allow collateral vessel stabilization. Many questions remain regarding other technical aspects, spinal cord monitoring and cooling, pharmacological protection, and the optimal duration of interventions into the postoperative period. PMID:27566805

  15. 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

  16. TEVAR: Endovascular Repair of the Thoracic Aorta

    PubMed Central

    Nation, David A.; Wang, Grace J.

    2015-01-01

    The development of thoracic endovascular aortic repair (TEVAR) has allowed a minimally invasive approach for management of an array of thoracic aortic pathologies. Initially developed specifically for exclusion of thoracic aortic aneurysms, TEVAR is now used as an alternative to open surgery for a variety of disease pathologies due to the lower morbidity of this approach. Advances in endograft technology continue to broaden the applications of this technique. PMID:26327745

  17. Endovascular treatment of frontopolar artery aneurysm.

    PubMed

    Karanam, Lakshmi S Prasanna; Alurkar, Anand; Chakka, Sivaramakrishna

    2016-08-01

    Traumatic intracranial aneurysms are rare and usually present with subarachnoid hemorrhage, intracranial hemorrhage, subdural hematoma, or intraventricular hemorrhage. These are usually not true aneurysms; hence treatment of these cases poses a therapeutic challenge. In this case report, we describe a young Asian male who presented with a ruptured pseudoaneurysm of the distal branch of the anterior cerebral artery. It was treated successfully with endovascular embolization. To our knowledge, there are few reports of this entity in the literature. PMID:27048313

  18. 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.

  19. 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.

  20. Endovascular Treatment in Spinal Perimedullary Arteriovenous Fistula

    PubMed Central

    Phadke, Rajendra V; Bhattacharyya, Avik; Handique, Akash; Jain, Krishan; Kumar, Alok; Singh, Vivek; Baruah, Deb; Kumar, Tushant; Patwari, Sriram; Mohan, B.Madan

    2014-01-01

    Summary This study includes 20 patients with 21 spinal perimedullary fistulae. There were nine Type IVa (42.8%) lesions, ten Type IVb (47.6%) and two Type IVc (9.5%) lesions. The dominant arterial supply was from the anterior spinal artery (47.6%), posterior spinal artery (19%) and directly from the radiculomedullary artery (28.5%). Sixteen lesions in 15 patients were treated by endovascular route using n-butyl-2-cyanoacrylate. Endovascular treatment was not feasible in five patients. Of the ten patients with microfistulae, catheterization failed/was not attempted in 40%, complete obliteration of the lesion was seen in 60% but clinical improvement was seen in 40% of patients. Catheterization was feasible in all ten patients with macrofistulae (nine type IVb and two type IVc lesions). Complete obliteration of the lesions was seen in 60% and residue in 30%. Clinical improvement was seen in 80% and clinical deterioration in 10%. In conclusion, endovascular glue embolization is safe and efficacious in type IVb and IVc spinal perimedullary fistulae and should be considered the first option of treatment. It is also feasible in many of the type IVa lesions. PMID:24976100

  1. Techniques for aortic arch endovascular repair.

    PubMed

    kHONGKU, 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. PMID:26940011

  2. 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. PMID:26944347

  3. Electrochemical removal of fluoride from water by PAOA-modified carbon felt electrodes in a continuous flow reactor.

    PubMed

    Cui, Hao; Qian, Yan; An, Hao; Sun, Chencheng; Zhai, Jianping; Li, Qin

    2012-08-01

    A novel poly(aniline-co-o-aminophenol) (PAOA) modified carbon felt electrode reactor was designed and investigated for fluoride removal from aqueous solutions. This reactor design is innovative because it operates under a wider pH range because of coating with a copolymer PAOA ion exchange film. In addition, contaminant mass transfer from bulk solution to the electrode surface is enhanced by the porous carbon felt as an electron-conducting carrier material compared to other reactors. The electrically controlled anion exchange mechanism was investigated by X-ray photoelectron spectroscopy and cyclic voltammetry. The applicability of the reactor in the field was tested through a series of continuous flow experiments. When the flow rate and initial fluoride concentration were increased, the breakthrough curve became sharper, which lead to a decrease in the breakthrough time and the defluoridation capacity of the reactor. The terminal potential values largely influenced fluoride removal by the reactor and the optimal defluoridation efficiency was observed at around 1.2V. The breakthrough capacities were all >10mg/g over a wide pH range (pH 5-9) with an initial fluoride concentration of 10mg/L. Consecutive treatment-regeneration studies over a week (once each day) revealed that the PAOA-modified carbon felt electrode could be effectively regenerated for reuse. The PAOA-modified carbon felt electrode reactor is a promising system that could be made commercially available for fluoride removal from aqueous solutions in field applications. PMID:22595483

  4. 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.

  5. 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.

  6. Noninvasive cerebral oximetry during endovascular therapy for acute ischemic stroke: an observational study.

    PubMed

    Hametner, Christian; Stanarcevic, Predrag; Stampfl, Sibylle; Rohde, Stefan; Veltkamp, Roland; Bösel, Julian

    2015-11-01

    Implementing endovascular stroke care often impedes neurologic assessment in patients who need sedation or general anesthesia. Cerebral near-infrared spectroscopy (NIRS) may help physicians monitor cerebral tissue viability, but data in hyperacute stroke patients receiving endovascular treatment are sparse. In this observational study, the NIRS index regional oxygen saturation (rSO2) was measured noninvasively before, during, and after endovascular therapy via bilateral forehead NIRS optodes. During the study period, 63 patients were monitored with NIRS; 43 qualified for analysis. Before recanalization, 10 distinct rSO2 decreases occurred in 11 patients with respect to time to intubation. During recanalization, two kinds of unilateral rSO2 changes occurred in the affected hemisphere: small peaks throughout the treatment (n=14, 32.6%) and sustained increases immediately after recanalization (n=2, 4.7%). Lower area under the curve 10% below baseline was associated with better reperfusion status (thrombolysis in cerebral infarction ≥ 2b, P=0.009). At the end of the intervention, lower interhemispheric rSO2 difference predicted death within 90 days (P=0.037). After the intervention, higher rSO2 variability predicted poor outcome (modified Rankin scale > 3, P=0.032). Our findings suggest that bi-channel rSO2-NIRS has potential for guiding neuroanesthesia and predicting outcome. To better monitor local revascularization, an improved stroke-specific set-up in future studies is necessary. PMID:26243709

  7. 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.

  8. A new ionic liquid dimethyldinonylammonium bromide as a flow modifier for the simultaneous determination of eight carboxylates by capillary electrophoresis.

    PubMed

    Laamanen, Pirkko-Leena; Busi, Sara; Lahtinen, Manu; Matilainen, Rose

    2005-11-18

    Two new methods of capillary zone electrophoresis based on aqueous phosphate running buffers with UV spectrophotometric detection were developed and optimized for the determination of eight carboxylates as copper complexes. Metalcomplexes are negatively charged, so measurements were made as anion analyses with flow reversal in the capillary. Two flow modifiers were used: a common tetradecyltrimethylammonium bromide (TTAB) and a new ionic liquid dimethyldinonylammonium bromide (DMDNAB). The methods were compared to each other. Better separation was achieved with DMDNAB as the flow modifier. Method development was done using a fused silica capillary (61 cm x 50 microm i.d.). Optimization was done using 95 mmol L(-1) phosphate buffer with TTAB or DMDNAB in the concentration 0.5 mmol L(-1) at pH 7.1. A -20 kV voltage and direct UV detection at 254 nm was used in measurements. In both CE methods all the peaks in the electropherograms were properly separated, the calibration plots gave good correlation coefficients and all eight carboxylates were detected in less than 7.5 min. The two methods were tested with natural water samples and a paper mill sample, and proved to be feasible. PMID:16275297

  9. 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.

  10. Flow injection analysis of phenolic compounds with carbon paste electrodes modified with tyrosinase purchased from different companies

    SciTech Connect

    Lindgren, A.; Emneus, J.; Csoeregi, E.; Gorton, L.; Marko-Varga, G.; Ruzgas, T.

    1996-05-01

    Tyrosinase-modified carbon paste electrodes were prepared using lyophilised powder of the enzyme purchased from different companies. The selectivity of these electrodes for nine phenolic compounds, including six substituted catechols, has been studied. The signals obtained for catechol were always higher than those found for other phenolic compounds. Cyclic voltammetry and flow injection measurements indicated that the response of the tyrosinase-modified carbon paste electrodes was limited by the rate of the enzymatic oxidation of catechols. Different approaches of past electrode preparation have been studied and compared. Direct mixing of enzyme into the graphite powder doped with the osmium based mediator, resulted in the highest sensitivity for the studied substrates. However, substrate selectivity was found to be dependent on the source of enzyme used for electrode preparation.

  11. 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...

  12. A Retrospective Study of Survivors of Endovascular Coiling for Posterior and Anterior Aneurysms

    PubMed Central

    Wilson, Sarah J.; Drackford, Ruth; Holt, Michael

    2015-01-01

    Abstract This article documents the longer-term medical and psychosocial outcomes of patients referred for endovascular coiling. There is limited research investigating outcome following endovascular coiling for posterior compared to anterior circulation aneurysms, and minimal understanding of how medical outcomes relate to patient experiences of treatment and quality of life. We studied a consecutive cohort of 80 patients referred Australia wide for endovascular coiling between 1995 and 2003 (49% posterior; 76% ruptured; 69% women, mean age 51.5 years). We used a mixed methods approach, assessing medical outcome with the Modified Rankin Scale (MRS) in 61 patients (76%), and health-related quality of life and psychosocial functioning using the EuroQol questionnaire and a qualitative semistructured interview in 49 patients (61%). Despite the high proportion of posterior aneurysms, the majority of patients (80%) showed good medical outcomes as indicated by regained independence of activities of daily living (MRS score ≤3). Patients with unruptured aneurysms were significantly more likely to show good outcomes (P < 0.04), whereas aneurysm location (posterior, anterior, or mixed) showed no significant effect. In patients with good medical outcomes, greater functional disability was associated with neurological complications surrounding treatment (P < 0.05). Good outcomes correlated with higher EuroQol ratings (P < 0.001) and the experience of less change after treatment (P < 0.001), although psychosocial adjustment issues were reported by most of the patients, including those with no medical symptoms. These results support the long-term efficacy of endovascular coiling, particularly for posterior circulation aneurysms. They have implications for guiding clinicians and patients in their choice of treatment, as well as the provision of psychological counseling for patient adjustment issues posttreatment. PMID:26266373

  13. 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.

  14. Transapical Endovascular Repair of an Ascending Aortic Pseudoaneurysm.

    PubMed

    Howell, Eric; Sweet, Matthew P; Pal, Jay D

    2016-07-01

    Proximal aortic pathology provides a technical challenge for endovascular repair. We present a case of successful transapical endovascular aortic repair in a patient with a proximal suture line pseudoaneurysm who was not a candidate for open surgical repair. doi: 10.1111/jocs.12766 (J Card Surg 2016;31:456-460). PMID:27183897

  15. 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.

  16. [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. PMID:26646614

  17. A modified Rusanov scheme for shallow water equations with topography and two phase flows

    NASA Astrophysics Data System (ADS)

    Mohamed, Kamel; Benkhaldoun, F.

    2016-06-01

    In this work, we introduce a finite volume method for numerical simulation of shallow water equations with source terms in one and two space dimensions, and one-pressure model of two-phase flows in one space dimension. The proposed method is composed of two steps. The first, called predictor step, depends on a local parameter allowing to control the numerical diffusion. A strategy based on limiters theory enables to control this parameter. The second step recovers the conservation equation. The scheme can thus be turned to order 1 in the regions where the flow has a strong variation, and order 2 in the regions where the flow is regular. The numerical scheme is applied to several test cases in one and two space dimensions. This scheme demonstrates its well-balanced property, and that it is an efficient and accurate approach for solving shallow water equations with and without source terms, and water faucet problem.

  18. 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.

  19. A modified Dodge algorithm for the parabolized Navier-Stokes equation and compressible duct flows

    NASA Technical Reports Server (NTRS)

    Cooke, C. H.

    1981-01-01

    A revised version of Dodge's split-velocity method for numerical calculation of compressible duct flow was developed. The revision incorporates balancing of mass flow rates on each marching step in order to maintain front-to-back continuity during the calculation. The (checkerboard) zebra algorithm is applied to solution of the three dimensional continuity equation in conservative form. A second-order A-stable linear multistep method is employed in effecting a marching solution of the parabolized momentum equations. A checkerboard iteration is used to solve the resulting implicit nonlinear systems of finite-difference equations which govern stepwise transition. Qualitive agreement with analytical predictions and experimental results was obtained for some flows with well-known solutions.

  20. A modified Dodge algorithm for the parabolized Navier-Stokes equations and compressible duct flows

    NASA Technical Reports Server (NTRS)

    Cooke, C. H.; Dwoyer, D. M.

    1983-01-01

    A revised version of Dodge's split-velocity method for numerical calculation of compressible duct flow was developed. The revision incorporates balancing of mass flow rates on each marching step in order to maintain front-to-back continuity during the calculation. The (checkerboard) zebra algorithm is applied to solution of the three dimensional continuity equation in conservative form. A second-order A-stable linear multistep method is employed in effecting a marching solution of the parabolized momentum equations. A checkerboard iteration is used to solve the resulting implicit nonlinear systems of finite-difference equations which govern stepwise transition. Qualitative agreement with analytical predictions and experimental results was obtained for some flows with well-known solutions. Previously announced in STAR as N82-16363

  1. A modified dodge algorithm for the parabolized Navier-Stokes equations and compressible duct flows

    NASA Technical Reports Server (NTRS)

    Cooke, C. H.

    1981-01-01

    A revised version of a split-velocity method for numerical calculation of compressible duct flow was developed. The revision incorporates balancing of mass flow rates on each marching step in order to maintain front-to-back continuity during the calculation. The (checkerboard) zebra algorithm is applied to solution of the three-dimensional continuity equation in conservative form. A second-order A-stable linear multistep method is employed in effecting a marching solution of the parabolized momentum equations. A checkerboard successive overrelaxation iteration is used to solve the resulting implicit nonlinear systems of finite-difference equations which govern stepwise transition.

  2. Results and challenges for the endovascular repair of aortic arch aneurysms.

    PubMed

    Lioupis, Christos; Abraham, Cherrie Z

    2011-09-01

    Endovascular aortic arch reconstruction provides an attractive alternative to treat aortic arch disease in high-risk patients who would otherwise be unsuitable for open repair. Success with multibranched stent grafts in the thoracoabdominal aorta along with recent advances in design such as the precurved inner nitinol cannula have simplified the endovascular reconstruction of aortic arch aneurysms with multibranched stent grafts. These devices allow for greater flexibility in conforming to difficult anatomy and preserving important side branches. During the first surgical stage, a left carotid -subclavian bypass or left subclavian artery transposition is performed. The second stage is the endovascular procedure. The device is inserted through a transfemoral approach, and crossing of the aortic valve with the device is necessary. The stent graft is deployed during brief periods of rapid pacing. Bridging from the branches to the innominate and left common carotid arteries requires a suitable covered stent. In the case of a large-diameter innominate artery, a custom-made bridging limb has to be used to ensure that adequate length and size are available. Direct flow to the innominate and left common carotid arteries do not cease for any significant time during the procedure. Initial experience with mean follow up more than 6 months is encouraging. The method is not suitable for patients with extensive atheromatous involvement of the aortic arch. Careful preoperative planning (preoperative imaging, device construction, and access issues), high endovascular skills, and appropriate imaging equipment are imperative for a successful result. Long-term follow-up is necessary to evaluate the efficacy and safety of these new devices. PMID:21821619

  3. 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

  4. 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

  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. Total endovascular repair of aberrant left subclavian artery with Kommerell's diverticulum using a customized branched device.

    PubMed

    Silveira, Pierre Galvagni; Franklin, Rafael Narciso; Cunha, Josué Rafael Ferreira; Neves, Thais Torres; Nascimento, Gilberto Galego; Bortoluzzi, Cristiano Torres

    2013-04-01

    We describe a case of Kommerell's diverticulum involving the distal portion of a right-sided aortic arch and the origin of an aberrant left subclavian artery (LSA). The patient underwent a total endovascular repair with the use of a modified Valiant endograft (Medtronic, Minneapolis, Minn) to which a branch was attached to keep LSA patency. Postoperative computed tomography showed complete exclusion of the lesion, without endoleaks. The use of "customized off-label" devices to treat special conditions was feasible in this case, keeping patency of the LSA without risk of arm claudication or the requirement for a complementary surgical bypass. PMID:23312832

  7. 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

  8. Radiological Evaluation and Endovascular Treatment of Hemoptysis.

    PubMed

    Ramírez Mejía, Alex Roberto; Méndez Montero, José Vicente; Vásquez-Caicedo, Marco Leyva; Bustos García de Castro, Ana; Cabeza Martínez, Beatriz; Ferreirós Domínguez, Joaquín

    2016-01-01

    Hemoptysis can be a life-threatening condition that warrants urgent investigation and intervention. Common causes include bronchiectasis, chronic obstructive pulmonary disease, tuberculosis, and malignancy. Computed tomography angiography is an accurate imaging modality for assessment of hemoptysis. The bronchial arteries are the source of bleeding in most cases of hemoptysis, and bronchial artery embolization is the treatment of choice. The aim of this article is to summarize the pathophysiology, causes, initial management, and diagnostic approach of hemoptysis. Endovascular treatment of hemoptysis, technique, embolic materials, outcomes, complications, and follow-up of patients are discussed. PMID:26293972

  9. 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

  10. An efficient modified Gabriel method for triangulating complex fractured media for multiphase flow simulations

    NASA Astrophysics Data System (ADS)

    Mustapha, Hussein; Rouxel-Labbé, Mael; Abbas, Hicham

    2013-10-01

    Fractured reservoirs and aquifers are complex domains where discrete fractures are internal constraining boundaries. The Delaunay triangulation of a fractured medium generally does not conform to the fracture boundaries and recovering the fracture elements may violate the Delaunay empty-circle (2D) criterion, which may lead to a low-quality triangulation. This paper presents a new approach based on the combined Gabriel and Delaunay methods. A modified Gabriel condition of edge-empty-circle is introduced. In a first stage, the fracture edges violating the modified Gabriel criterion are released and then followed by a Delaunay triangulation with the rest of the fracture constraints. The released fracture edges are approximated by the edges of the Delaunay triangles in a postprocessing stage. The final representation of the fractures might be slightly different, but a very accurate solution is always maintained. The method has the capability to generate fine grids and to offer an accurate and good-quality grid. Numerical examples are presented to assess the efficiency of the proposed method.

  11. Modified hydrodynamics in canopies with longitudinal gaps exposed to oscillatory flows

    NASA Astrophysics Data System (ADS)

    El Allaoui, Nazha; Serra, Teresa; Soler, Marianna; Colomer, Jordi; Pujol, Dolors; Oldham, Carolyn

    2015-12-01

    Longitudinal gaps are commonly found in aquatic canopies. While the ecological significance of gaps may be large, we know little about their impact on the hydrodynamics within the canopy. We used laboratory experiments to investigate the effect of longitudinal gaps within canopies exposed to a wave field. In rigid submerged and emergent vegetation, wave velocities were reduced compared to the case without vegetation. Flexible canopies also attenuated waves, but this attenuation was lower than for rigid canopies. The presence of the gap modified the mean current associated with the waves in both the gap and the lateral vegetation. A gap within a canopy of 5% solid plant fraction did not show differences in the wave attenuation between the gap and the lateral vegetation. In contrast, gaps within canopies of 10% solid plant fraction resulted in large differences between the gap and the lateral vegetation. In all the experiments, the effect of a gap within a canopy reduced the wave attenuation within the lateral vegetation adjacent to the gap when compared with a canopy without a gap. In canopies with rigid plants, the lateral vegetation modified the wave attenuation in the nearby gap. In contrast, the lateral flexible vegetation did not produce any effect on the wave attenuation of the adjacent gap. Canopy density, plant height and plant flexibility were critical for determining the hydrodynamics throughout the canopy and in the gap.

  12. 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.

  13. MODIFIED CHOKE FLOW CRITERION FOR THE TWO-PHASE TWO-FLUID MODEL

    SciTech Connect

    Suneet Singh; Vincent A. Mousseau

    2009-05-01

    A choked condition exists when mass flow rate becomes independent of the downstream conditions. In other words, no information can propagate in the upstream direction under this condition. The real part of the solution of the characteristic equation for the model represents velocity of the signal propagation and the imaginary part is the growth (or decay) rate of that signal. Therefore, if the real part of these eigenvalues is positive then no signal propagates in the upstream direction (choosing downstream direction to be the positive direction) resulting in the choke flow. In order to develop the choke criterion, a non-dimensional form of the characteristic equation is derived for the standard two-phase two-fluid model. The equation is in the terms of a slip Mach number Ms. It can be shown that the slip Mach number is small for many applications including nuclear reactor safety simulations. The eigenvalues of the characteristic equation are obtained as a power series expansion about the point Ms = 0. These eigenvalues are used to develop a choking criterion for the compressible two-phase flows.

  14. 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

  15. 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.

  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. 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.

  18. A mathematical representation of a modified stagnation flow reactor for MOCVD applications

    NASA Astrophysics Data System (ADS)

    Dilawari, A. H.; Szekely, J.

    1991-02-01

    Computed results are presented describing the behavior of a modified stagnation point reactor for an MOCVD system, employing a showerhead type gas distributor. The principal findings of the work are the following: (a) By this arrangement, it is possible to obtain a very high spatial uniformity in the deposition rate, in cases better than 0.35% for a five inch diameter wafer. (b) Both the absolute values of the gas velocity and the standoff distance were found to play a critical role in affecting the uniformity of the deposition rate. Indeed a small standoff distance was found to be an essential ingredient in obtaining a good spatial uniformity of the deposit. (c) "An upside down" orientation was found to be helpful in minimizing thermal natural convection and a further refinement was found to be possible by imposing a desired radial distribution on the gas inlet velocity profile.

  19. Nanoscale Poiseuille flow and effects of modified Lennard-Jones potential function

    NASA Astrophysics Data System (ADS)

    Toghraie Semiromi, D.; Azimian, A. R.

    2010-08-01

    Numerical simulation of Poiseuille flow of liquid Argon in a nanochannel using the non-equilibrium molecular dynamics simulation (NEMD) is performed. The nanochannel is a three-dimensional rectangular prism geometry where the concerned numbers of Argon atoms are 2,700, 2,550 and 2,400 at 102, 108 and 120 K. Poiseuille flow is simulated by embedding the fluid particles in a uniform force field. An external driving force, ranging from 1 to 11 PN (Pico Newton), is applied along the flow direction to inlet fluid particles during the simulation. To obtain a more uniform temperature distribution across the channel, local thermostating near the wall are used. Also, the effect of other mixing rules (Lorenthz-Berthelot and Waldman-Kugler rules) on the interface structure are examined by comparing the density profiles near the liquid/solid interfaces for wall temperatures 108 and 133 K for an external force of 7 PN. Using Kong and Waldman-Kugler rules, the molecules near the solid walls were more randomly distributed compared to Lorenthz-Berthelot rule. These mean that the attraction between solid-fluid atoms was weakened by using Kong rule and Waldman-Kugler rule rather than the Lorenthz-Berthelot rule. Also, results show that the mean axial velocity has symmetrical distribution near the channel centerline and an increase in external driving force can increase maximum and average velocity values of fluid. Furthermore, the slip length and slip velocity are functions of the driving forces and they show an arising trend with an increase in inlet driving force and no slip boundary condition is satisfied at very low external force (<1 PN).

  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. Experimental Subarachnoid Hemorrhage in Rats: Comparison of Two Endovascular Perforation Techniques with Respect to Success Rate, Confounding Pathologies and Early Hippocampal Tissue Lesion Pattern

    PubMed Central

    Höllig, Anke; Weinandy, Agnieszka; Nolte, Kay; Clusmann, Hans; Rossaint, Rolf; Coburn, Mark

    2015-01-01

    Recently aside from the “classic” endovascular monofilament perforation technique to induce experimental subarachnoid hemorrhage (SAH) a modification using a tungsten wire advanced through a guide tube has been described. We aim to assess both techniques for their success rate (induction of SAH without confounding pathologies) as primary endpoint. Further, the early tissue lesion pattern as evidence for early brain injury will be analyzed as secondary endpoint. Sprague Dawley rats (n=39) were randomly assigned to receive either Sham surgery (n=4), SAH using the “classic” technique (n=18) or using a modified technique (n=17). Course of intracranial pressure (ICP) and regional cerebral blood flow (rCBF) was analyzed; subsequent pathologies were documented either 6 or 24 h after SAH. Hippocampal tissue samples were analyzed via immunohistochemistry and western blotting. SAH-induction, regardless of confounding pathologies, was independent from type of technique (p=0.679). There was no significant difference concerning case fatality rate (classic: 40%; modified: 20%; p=0.213). Successful induction of SAH without collateral ICH or SDH was possible in 40% with the classic and in 86.7% with the modified technique (p=0.008). Peak ICP levels differed significantly between the two groups (classic: 94 +/- 23 mmHg; modified: 68 +/- 19 mmHg; p=0.003). Evidence of early cellular stress response and activation of apoptotic pathways 6 h after SAH was demonstrated. The extent of stress response is not dependent on type of technique. Both tested techniques successfully produce SAH including activation of an early stress response and apoptotic pathways in the hippocampal tissue. However, the induction of SAH with less confounding pathologies was more frequently achieved with the modified tungsten wire technique. PMID:25867893

  2. [Endovascular repair for coarctation of the aorta in an adult].

    PubMed

    Hayashi, Jun; Abe, Kazuo; Hata, Masaki; Nagano, Naoko; Hamasaki, Azumi; Suzuki, Kenji

    2013-09-01

    A 27-year-old woman with Turner's syndrome who underwent successful endovascular treatment for coarctation of the aorta is presented. She was admitted to our hospital complaining of upper extremity hypertension. Computed tomography revealed discrete stenosis of the proximal descending aorta and developed collateral circulation. After endovascular repair with a balloon expandable stent, her transcoarctation gradient fell from 44 mmHg preoperatively to less than 10 mmHg. She was discharged with no complications on the 7th postoperative day. Coarctation of the aorta in an adult patient could be safely and effectively managed by endovascular treatment. PMID:24008641

  3. General technical considerations for the endovascular management of cerebral aneurysms.

    PubMed

    Eboli, Paula; Ryan, Robert W; Alexander, Michael J

    2014-07-01

    Cerebral aneurysms pose a threat to patients because of their risk of rupture causing subarachnoid hemorrhage, and the goal of treatment is the exclusion of the aneurysm from the circulation to prevent bleeding (in the case of unruptured aneurysms) or rebleeding. This article analyzes the general technical factors associated with the endovascular treatment of cerebral aneurysms. It discusses issues with transarterial access; imaging of aneurysm size, morphology, and regional anatomy to determine the endovascular plan; the techniques for the major endovascular aneurysm devices; and periprocedural management issues to reduce potential treatment-related complications. PMID:24994079

  4. 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.

  5. Endovascular aortic repair: first twenty years.

    PubMed

    Koncar, Igor; Tolić, Momcilo; Ilić, Nikola; Cvetković, Slobodan; Dragas, Marko; Cinara, Ilijas; Kostić, Dusan; Davidović, Lazar

    2012-01-01

    Endovascular aortic/aneurysm repair (EVAR) was introduced into clinical practice at the beginning of the nineties. Its fast development had a great influence on clinicians, vascular surgeons and interventional radiologists, educational curriculums, patients, industry and medical insurance. The aim of this paper is to present the contribution of clinicians and industry to the development and advancement of endovascular aortic repair over the last 20 years. This review article presents the development of EVAR by focusing on the contribution of physicians, surgeons and interventional radiologists in the creation of the new field of vascular surgery termed hybrid vascular surgery, and also the contribution of technological advancement by a significant help of industrial representatives--engineers and their counselors. This article also analyzes studies conducted in order to compare the successfulness of EVAR with up-to-now applied open surgical repair of aortic aneurysms, and some treatment techniques of other aortic diseases. During the first two decades of its development the EVAR method was rapidly progressing and was adopted concurrently with the expansion of technology. Owing to large randomized studies, early and long-term results indicate specific complications of this method, thus influencing further technological improvement and defining risk patients groups in whom the use of the technique should be avoided. Good results are insured only in centers, specialized in vascular surgery, which have on their disposal adequate conditions for solving all complications associated with this method. PMID:23350259

  6. 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.

  7. Endovascular treatment of abdominal aortic aneurysms.

    PubMed

    Buck, Dominique B; van Herwaarden, Joost A; Schermerhorn, Marc L; Moll, Frans L

    2014-02-01

    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

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

    PubMed Central

    McGah, Patrick M.; Levitt, Michael R.; Barbour, Michael C.; Morton, Ryan P.; Nerva, John D.; Mourad, Pierre D.; Ghodke, Basavaraj V.; Hallam, Danial K.; Sekhar, Laligam N.; Kim, Louis J.; Aliseda, Alberto

    2013-01-01

    Computational hemodynamic simulations of cerebral aneurysms have traditionally relied on stereotypical boundary conditions (such as blood flow velocity and blood pressure) derived from published values as patient-specific measurements are unavailable or difficult to collect. However, controversy persists over the necessity of incorporating such patient specific conditions into computational analyses. We perform simulations using both endovascular-derived patient-specific and typical literature-derived inflow and outflow boundary conditions. Detailed three-dimensional anatomical models of the cerebral vasculature are developed from rotational angiography data, and blood flow velocity and pressure are measured in situ by a dual-sensor pressure and velocity endovascular guidewire at multiple peri-aneurysmal locations in ten unruptured cerebral aneurysms. These measurements are used to define inflow and outflow boundary conditions for computational hemodynamic models of the aneurysms. The additional in situ measurements which are not prescribed in the simulation are then used to assess the accuracy of the simulated flow velocity and pressure drop. Simulated velocities using patient-specific boundary conditions show good agreement with the guidewire measurements at measurement locations inside the domain, with no bias in the agreement and a random scatter of ≈25%. Simulated velocities using the simplified, literature-derived values show a systematic bias and over-predicted velocity by ≈30% with a random scatter of ≈40%. Computational hemodynamics using endovascularly measured patient-specific boundary conditions have the potential to improve treatment predictions as they provide more accurate and precise results of the aneurysmal hemodynamics than those based on commonly accepted reference values for boundary conditions. PMID:24162859

  9. 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).

  10. Protein Adsorption on Chemically Modified Block Copolymer Nanodomains: Influence of Charge and Flow.

    PubMed

    Silverstein, Joshua S; Casey, Brendan J; Kofinas, Peter; Dair, Benita J

    2016-02-01

    Understanding the interactions of biomacromolecules with nanoengineered surfaces is vital for assessing material biocompatibility. This study focuses on the dynamics of protein adsorption on nanopatterned block copolymers (BCPs). Poly(styrene)-block-poly(1,2-butadiene) BCPs functionalized with an acid, amine, amide, or captopril moieties were processed to produce nanopatterned films. These films were characterized using water contact angle measurements and atomic force microscopy in air and liquid to determine how the modification process affected. wettability and swelling. Protein adsorption experiments were conducted under static and dynamic conditions via a quartz crystal microbalance with dissipation. Proteins of various size, charge, and stability were investigated to determine whether their physical characteristics affected adsorption. Significantly decreased contact angles were caused by selective swelling of modified BCP domains. The results indicate that nanopatterned chemistry and experimental conditions strongly impact adsorption dynamics. Depending on the structural stability of the protein, polyelectrolyte surfaces significantly increased adsorption over controls. Further analysis suggested that protein stability may correlate with dissipation versus frequency plots. PMID:27433605

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. Instability of electrically-driven MHD flow in a modified cylindrical annulus filled with liquid GaInSn

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

    Planetary magnetic fields such as that of the Earth are thought to be generated by motions of electrically conducting fluids and can be described by the theory of magnetohydrodynamics (MHD). Liquid cores of such astrophysical bodies are dominated by Coriolis and Lorentz forces. Instabilities developing in this magnetostrophic regime are poorly known, numerical studies being far from the actual parameters. We study the destabilization of a flow of liquid GaInSn in a modified cylindrical annulus experimentally and numerically. The flow is driven by the Lorentz force resulting from the injection of a radial electrical current under an imposed axial magnetic field. The novel feature compared to previous studies with similar geometry [Moresco and Alboussière, JFM, 2004] is the form of the electrodes, the inner one being a disk electrode, the outer one a ring electrode. A shear layer, termed the Shercliff layer, develops at the edge of the disk electrode. Using magnetic fields up to 1 T and forcing currents up to 150 A, we reach Hartmann numbers up to 2000 and Reynolds numbers of the order of 10 ^ 5 which are hardly accessible in numerical simulations. We measure the liquid-metal motions by ultrasonic Doppler velocimetry and potential differences. We characterize the flow in terms of a mean flow and fluctuations. Initiating from the Shercliff layer at low forcing currents, we observe mainly monochromatic oscillations that grow in frequency and space with increasing forcing current and magnetic field strength. The threshold of instabilities is dependent on the field strength. For the regime of low Hartmann and Reynolds numbers, we also perform numerical simulations of the flow in our setup using the quasi-static approximation. With 2.5 D finite element modelling, we are able to track the threshold of linear stability for the base flow. First results coincide well with the observations from the lab experiment. Future experiments are currently developed to further

  16. 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.

  17. Technical tips for successful outcomes using adjunctive procedures during endovascular aortic aneurysm repair.

    PubMed

    Kasirajan, Karthikeshwar; Gupta, Naren

    2012-09-01

    The inability to obtain proximal or distal seal continues to remain one of the main challenges of endovascular aneurysm repair. This is particularly relevant when endografts are used in patients with unsuitable proximal or distal landing zones. A variety of techniques can be used to achieve a seal in these difficult situations. Two specific techniques that can help intraoperatively to resolve the lack of adequate graft to aortic wall opposition are discussed in this article. These include the use of Palmaz stents for proximal seal and hypogastric snorkel for distal seal with internal iliac flow preservation. PMID:23062496

  18. 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.

  19. 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

  20. 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. PMID:27132528

  1. 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.

  2. 21 CFR 870.3460 - Endovascular Suturing System.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... prescription use in accordance with 21 CFR 801.109 of this chapter; and (7) Labeling must bear all information... fixation and sealing between an endovascular graft and the native artery. The system is comprised of...

  3. 21 CFR 870.3460 - Endovascular Suturing System.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... prescription use in accordance with 21 CFR 801.109 of this chapter; and (7) Labeling must bear all information... fixation and sealing between an endovascular graft and the native artery. The system is comprised of...

  4. 21 CFR 870.3460 - Endovascular Suturing System.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... prescription use in accordance with 21 CFR 801.109 of this chapter; and (7) Labeling must bear all information... fixation and sealing between an endovascular graft and the native artery. The system is comprised of...

  5. 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

  6. Considerations for patients undergoing endovascular abdominal aortic aneurysm repair.

    PubMed

    Ullery, Brant W; Lee, Jason T

    2014-09-01

    Endovascular aneurysm repair has taken over open surgery as the primary strategy for treatment of patients with abdominal and thoracic aneurysms. The minimally invasive nature of these techniques requires alterations in preoperative workup, intraoperative management, and familiarity with unique complications that can occur. Familiarity from the anesthetic standpoint of endovascular techniques, including treatment of patients with fenestrated, chimney, snorkel, and periscope grafts, is necessary for the contemporary cardiac anesthesiologist. PMID:25113729

  7. Detection of thrombosis and restenosis in an endovascular stent

    NASA Astrophysics Data System (ADS)

    Wu, Junru; Weissman, Eric

    2002-05-01

    Endovascular stents that are implanted in an artery are often used in the interventional treatment of coronary artery disease. Its widespread applications are, however, limited by the development of subacute thrombosis (clot forming inside of the stent). Ex vivo experiments with pigs have shown that the broadband A-mode ultrasound is quite effective in detection thrombosis and restenosis in an endovascular stent. [Work supported by BFGoodrich and Noveon, Inc.

  8. 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. PMID:26592613

  9. Angiographic outcome of endovascular stroke therapy correlated with MR findings, infarct growth, and clinical outcome in the DEFUSE 2 trial

    PubMed Central

    Marks, Michael P.; Lansberg, Maarten G.; Mlynash, Michael; Kemp, Stephanie; McTaggart, Ryan A.; Zaharchuk, Greg; Bammer, Roland; Albers, Gregory W.

    2015-01-01

    Background 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. Methods 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. Results 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. Conclusion Thrombolysis in cerebral infarction reperfusion following endovascular therapy for

  10. 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.

  11. 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.

  12. 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

  13. 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

  14. Endovascular Management of Sigmoid Sinus Diverticulum.

    PubMed

    Paramasivam, Srinivasan; Furtado, Sunil; Shigamatsu, Tomoyoshi; Smouha, Eric

    2016-06-01

    Sigmoid sinus diverticulum (SSD) is a rare vascular disorder due to dehiscence of the sigmoid plate. It may be associated with prediverticular venous sinus stenosis (SS) and usually presents as pulsatile tinnitus. The mechanism of development of the SSD and tinnitus from a sinus diverticulum and associated SS is unclear. Previous case reports have suggested that remodeling of the venous system targeting the stenosis, elimination of the diverticulum, or both, have resulted in symptom relief. We present a case of SSD with SS, treated by stenting of the stenosis along with coil embolization of the diverticulum, resulting in complete relief of symptoms. We have also reviewed the literature and discussed the evolution of management from open surgical treatment to endovascular treatment. PMID:27610124

  15. 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

  16. 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.

  17. Endovascular Management of Sigmoid Sinus Diverticulum

    PubMed Central

    Paramasivam, Srinivasan; Furtado, Sunil; Shigamatsu, Tomoyoshi; Smouha, Eric

    2016-01-01

    Sigmoid sinus diverticulum (SSD) is a rare vascular disorder due to dehiscence of the sigmoid plate. It may be associated with prediverticular venous sinus stenosis (SS) and usually presents as pulsatile tinnitus. The mechanism of development of the SSD and tinnitus from a sinus diverticulum and associated SS is unclear. Previous case reports have suggested that remodeling of the venous system targeting the stenosis, elimination of the diverticulum, or both, have resulted in symptom relief. We present a case of SSD with SS, treated by stenting of the stenosis along with coil embolization of the diverticulum, resulting in complete relief of symptoms. We have also reviewed the literature and discussed the evolution of management from open surgical treatment to endovascular treatment. PMID:27610124

  18. Endovascular approach for ruptured abdominal aortic aneursyms.

    PubMed

    Setacci, F; Sirignano, P; De Donato, G; Chisci, E; Galzerano, G; Cappelli, A; Palasciano, G; Setacci, C

    2010-06-01

    The rupture of an abdominal aortic aneurysm (rAAA) causes about 15000 deaths/year in the USA alone. Even though over the last 50 years progress in surgical techniques and in postoperative intensive care have been outstanding, the analysis of registries has shown either no decrease in the mortality rate for surgically treated rAAAs. Some reports asserted better out come for endovascular repair (EVAR) compared with surgery in case of rAAA. Despite this evidence, EVAR for rAAA remains prerogative of few centers worldwide. In conclusion only larger study or registry could assest the real role of EVAR in the management of rAAA. PMID:20523280

  19. Novel temporary endovascular shunt technique to assist in situ fenestration for endovascular reconstruction of the distal aortic arch.

    PubMed

    Xiong, Jiang; Guo, Wei; Liu, Xiaoping; Jia, Xin; Ma, Xiaohui; Wang, Lijun

    2015-07-01

    Thoracic endovascular aortic repair (TEVAR) of arch pathology presents special challenges for revascularization. To obtain an anatomic reconstruction of the arch arteries, in situ fenestration with extra-anatomic bypass has been increasingly used in TEVAR. We report a case involving TEVAR for a pseudoaneurysm at zone 2 of the thoracic aorta in a 37-year-old man with the use of in situ fenestration assisted by a temporary endovascular shunt technique. PMID:24560242

  20. Comparative outcome analysis of anterior choroidal artery aneurysms treated with endovascular coiling or surgical clipping

    PubMed Central

    Aoki, Takachika; Hirohata, Masaru; Noguchi, Kei; Komaki, Satoru; Orito, Kimihiko; Morioka, Motohiro

    2016-01-01

    Background: Treatment of anterior choroidal artery (AChA) aneurysms with endovascular coiling or surgical clipping may increase the risk of ischemic complications owing to the critical territory supplied by the AChA. We analyzed the surgical results of endovascular coiling and surgical clipping for AChA aneurysms performed in a single institution, as well as the role of indocyanine green-videoangiography (ICG-VAG) and motor-evoked potential (MEP). Methods: We analyzed 50 patients (51 aneurysms; 21 men, 29 women; mean age: 58 years) including 25 with subarachnoid hemorrhage treated with endovascular coiling or surgical clipping between April 1990 and October 2013. The complication rates and clinical outcomes of the coil group (mean follow-up: 61 months) and the clip group (mean follow-up: 121 months) were analyzed with a modified Rankin scale. Results: The overall clinical outcome of the coil group (95%) was better than that of the clip group (85%). Especially, the outcomes in the coil group were better in the first investigated period (1990–2007) (P < 0.05). However, after the introduction of ICG-VAG and MEP, the outcomes in the clip group improved significantly (P = 0.005), and treatment-related complications decreased from 20 to 4.7%. Eleven aneurysms (coil group: 8, clip group: 3) showed small neck remnants but no remarkable regrowth, except for 1 case during the mean follow-up period of 91 months. Conclusions: Surgical clipping of AChA aneurysms has become safer because of ICG-VAG and MEP monitoring. Coiling and clipping of AChA aneurysms showed good and comparable outcomes with these monitoring methods.

  1. 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

  2. 77 FR 8117 - Medical Devices; Cardiovascular Devices; Classification of the Endovascular Suturing System

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-14

    ... fixation and sealing between an endovascular graft and the native artery. The system is comprised of the... provide fixation and sealing between an endovascular graft and the native artery. The system is...

  3. 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.

  4. 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

    2015-10-01

    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. PMID:26341593

  5. 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

  6. 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.

  7. Influence of the Modifier Type and its Concentration on Electroosmotic Flow of the Mobile Phase in Pressurized Planar Electrochromatography.

    PubMed

    Hałka-Grysińska, Aneta; Płocharz, Paweł W; Torbicz, Andrzej; Skwarek, Ewa; Janusz, Władysław; Dzido, Tadeusz H

    2014-01-01

    The aim of this work was to find a relationship between electroosmotic flow (EOF) velocity of the mobile phase in pressurized planar electrochromatography (PPEC) and physicochemical properties like zeta potential, dielectric constant, and viscosity of the mobile phase as well as its composition. The study included different types of organic modifiers (acetonitrile, methanol, ethanol, acetone, formamide, N-methylformamide and N,N-dimethylformamide) in the full concentration range. In all experiments, chromatographic glass plates HPTLC RP-18 W from Merck (Darmstadt) were used as a stationary phase. During the study we found that there is no linear correlation between EOF velocity of the mobile phase and single variables such as zeta potential or dielectric constant or viscosity. However, there is quite strong linear correlation between EOF velocity of the mobile phase and variable obtained by multiplying zeta potential of the stationary phase-mobile phase interface, by dielectric constant of the mobile phase solution and dividing by viscosity of the mobile phase. Therefore, it could be concluded that the PPEC system fulfilled the Helmholtz-Smoluchowski equation. PMID:25067847

  8. 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

  9. [Retrograde type A dissection after endovascular stent grafting of type B dissection].

    PubMed

    Misfeld, M; Nötzold, A; Geist, V; Richardt, G; Sievers, H H

    2002-03-01

    Acute aortic dissection is a disease with high mortality. Whereas acute dissection of the ascending aorta (Standford type A) is treated surgically, acute dissection of Stanford type B (descending aorta) is principally treated conservatively, but surgically in case of complications. Recently, another therapeutical option for the treatment of type B dissection has been developed using endovascular stent-grafts. We report on a 64-year-old woman with typical signs of acute aortic dissection. Computer tomography and transesophageal echocardiography demonstrated Stanford type B dissection. The patient was treated with an endovascular stent-graft, because of malperfusion of the right leg and chest pain. After successful closure of the entry by the stent, the patient developed acute right-sided hemiplegia one day after the intervention due to retrograde dissection into the aortic arch and ascending aorta. Upon immediate operation, the origin of the initially type B dissection was still sufficiently occluded by the endovascular stent-graft; however, there was another entry between the innominate artery and the left carotic artery near one proximal end of the stent's strut. Using deep hypothermia and selective antegrade cerebral perfusion, the ascending aorta and proximal arch were replaced with a 28 mm Dacron-Velour tube and the aortic root was remodelled with a tongue-shaped Dacron graft preserving the valve cusps according to a modified Yacoub procedure. After the operation, neurological symptoms diminished and the patient could walk on the ward on day eleven. This case demonstrates retrograde type A dissection as a complication after interventional treatment of type B dissection using an endovascular stent-graft. The reason for this delayed complication is speculative. Aortic wall damage during stent inserting could be a possible cause. It is also likely that the patient initially had type B dissection with retrograde dissection of the distal part of the aortic arch

  10. Critical early thrombolytic and endovascular reperfusion therapy for acute ischemic stroke victims: a call for adjunct neuroprotection.

    PubMed

    Lapchak, Paul A

    2015-10-01

    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 activator (rt-PA) clinical trials [i.e., National Institute of Neurological Disorders and Stroke (NINDS) rt-PA 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

  11. Treatment protocol based on assessment of clot quality during endovascular thrombectomy for acute ischemic stroke using the Trevo stent retriever

    PubMed Central

    Ishikawa, Kojiro; Ohshima, Tomotaka; Nishihori, Masahiro; Imai, Tasuku; Goto, Shunsaku; Yamamoto, Taiki; Nishizawa, Toshihisa; Shimato, Shinji; Kato, Kyozo

    2016-01-01

    ABSTRACT The optional endovascular approach for acute ischemic stroke is unclear. The Trevo stent retriever can be used as first-line treatment for fast mechanical recanalization. The authors developed a treatment protocol for acute ischemic stroke based on the assessment of clot quality during clot removal with the Trevo. This prospective single-center study included all patients admitted for acute ischemic stroke between July 2014 and February 2015, who underwent emergency endovascular treatment. According to the protocol, the Trevo was used for first-line treatment. Immediately after the Trevo was deployed, the stent delivery wire was pushed to open the stent by force (ACAPT technique). Clot quality was assessed on the basis of the perfusion status after deployment of the Trevo; continued occlusion or immediate reopening either reoccluded or maintained after the stent retriever had been in place for 5 min. If there was no obvious clot removal after the first pass with the Trevo, according to the quality of the clot, either a second pass was performed or another endovascular device was selected. Twelve consecutive patients with acute major cerebral artery occlusion were analyzed. Thrombolysis in cerebral infarction score 2b and 3 was achieved in 11 patients (91.7%) and 9 (75%) had a good clinical outcome after 90 days based on a modified Rankin scale score ≤ 2. Symptomatic intracranial hemorrhage occurred in 1 patient (8.3%). The overall mortality rate was 8.3%. Endovascular thrombectomy using the Trevo stent retriever for first-line treatment is feasible and effective. PMID:27578909

  12. Treatment protocol based on assessment of clot quality during endovascular thrombectomy for acute ischemic stroke using the Trevo stent retriever.

    PubMed

    Ishikawa, Kojiro; Ohshima, Tomotaka; Nishihori, Masahiro; Imai, Tasuku; Goto, Shunsaku; Yamamoto, Taiki; Nishizawa, Toshihisa; Shimato, Shinji; Kato, Kyozo

    2016-08-01

    The optional endovascular approach for acute ischemic stroke is unclear. The Trevo stent retriever can be used as first-line treatment for fast mechanical recanalization. The authors developed a treatment protocol for acute ischemic stroke based on the assessment of clot quality during clot removal with the Trevo. This prospective single-center study included all patients admitted for acute ischemic stroke between July 2014 and February 2015, who underwent emergency endovascular treatment. According to the protocol, the Trevo was used for first-line treatment. Immediately after the Trevo was deployed, the stent delivery wire was pushed to open the stent by force (ACAPT technique). Clot quality was assessed on the basis of the perfusion status after deployment of the Trevo; continued occlusion or immediate reopening either reoccluded or maintained after the stent retriever had been in place for 5 min. If there was no obvious clot removal after the first pass with the Trevo, according to the quality of the clot, either a second pass was performed or another endovascular device was selected. Twelve consecutive patients with acute major cerebral artery occlusion were analyzed. Thrombolysis in cerebral infarction score 2b and 3 was achieved in 11 patients (91.7%) and 9 (75%) had a good clinical outcome after 90 days based on a modified Rankin scale score ≤ 2. Symptomatic intracranial hemorrhage occurred in 1 patient (8.3%). The overall mortality rate was 8.3%. Endovascular thrombectomy using the Trevo stent retriever for first-line treatment is feasible and effective. PMID:27578909

  13. A Retrospective Study of Survivors of Endovascular Coiling for Posterior and Anterior Aneurysms: Medical and Patient Perspectives.

    PubMed

    Wilson, Sarah J; Drackford, Ruth; Holt, Michael

    2015-08-01

    This article documents the longer-term medical and psychosocial outcomes of patients referred for endovascular coiling.There is limited research investigating outcome following endovascular coiling for posterior compared to anterior circulation aneurysms, and minimal understanding of how medical outcomes relate to patient experiences of treatment and quality of life.We studied a consecutive cohort of 80 patients referred Australia wide for endovascular coiling between 1995 and 2003 (49% posterior; 76% ruptured; 69% women, mean age 51.5 years). We used a mixed methods approach, assessing medical outcome with the Modified Rankin Scale (MRS) in 61 patients (76%), and health-related quality of life and psychosocial functioning using the EuroQol questionnaire and a qualitative semistructured interview in 49 patients (61%).Despite the high proportion of posterior aneurysms, the majority of patients (80%) showed good medical outcomes as indicated by regained independence of activities of daily living (MRS score ≤3). Patients with unruptured aneurysms were significantly more likely to show good outcomes (P < 0.04), whereas aneurysm location (posterior, anterior, or mixed) showed no significant effect. In patients with good medical outcomes, greater functional disability was associated with neurological complications surrounding treatment (P < 0.05). Good outcomes correlated with higher EuroQol ratings (P < 0.001) and the experience of less change after treatment (P < 0.001), although psychosocial adjustment issues were reported by most of the patients, including those with no medical symptoms.These results support the long-term efficacy of endovascular coiling, particularly for posterior circulation aneurysms. They have implications for guiding clinicians and patients in their choice of treatment, as well as the provision of psychological counseling for patient adjustment issues posttreatment. PMID:26266373

  14. 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

  15. Computational modeling of an endovascular approach to deep brain stimulation

    NASA Astrophysics Data System (ADS)

    Teplitzky, Benjamin A.; Connolly, Allison T.; Bajwa, Jawad A.; Johnson, Matthew D.

    2014-04-01

    Objective. Deep brain stimulation (DBS) therapy currently relies on a transcranial neurosurgical technique to implant one or more electrode leads into the brain parenchyma. In this study, we used computational modeling to investigate the feasibility of using an endovascular approach to target DBS therapy. Approach. Image-based anatomical reconstructions of the human brain and vasculature were used to identify 17 established and hypothesized anatomical targets of DBS, of which five were found adjacent to a vein or artery with intraluminal diameter ≥1 mm. Two of these targets, the fornix and subgenual cingulate white matter (SgCwm) tracts, were further investigated using a computational modeling framework that combined segmented volumes of the vascularized brain, finite element models of the tissue voltage during DBS, and multi-compartment axon models to predict the direct electrophysiological effects of endovascular DBS. Main results. The models showed that: (1) a ring-electrode conforming to the vessel wall was more efficient at neural activation than a guidewire design, (2) increasing the length of a ring-electrode had minimal effect on neural activation thresholds, (3) large variability in neural activation occurred with suboptimal placement of a ring-electrode along the targeted vessel, and (4) activation thresholds for the fornix and SgCwm tracts were comparable for endovascular and stereotactic DBS, though endovascular DBS was able to produce significantly larger contralateral activation for a unilateral implantation. Significance. Together, these results suggest that endovascular DBS can serve as a complementary approach to stereotactic DBS in select cases.

  16. Improving patient selection for endovascular treatment of acute cerebral ischemia: a review of the literature and an external validation of the Houston IAT and THRIVE predictive scoring systems.

    PubMed

    Ishkanian, Amy A; McCullough-Hicks, Margy E; Appelboom, Geoffrey; Piazza, Matthew A; Hwang, Brian Y; Bruce, Samuel S; Hannan, Lindsay M; Connolly, E Sander; Lavine, Sean D; Meyers, Philip M

    2011-06-01

    Outcome after intraarterial therapy (IAT) for acute ischemic stroke remains variable, suggesting that improved patient selection is needed to better identify patients likely to benefit from treatment. The authors evaluate the predictive accuracies of the Houston IAT (HIAT) and the Totaled Health Risks in Vascular Events (THRIVE) scores in an independent cohort and review the existing literature detailing additional predictive factors to be used in patient selection for IAT. They reviewed their center's endovascular records from January 2004 to July 2010 and identified patients who had acute ischemic stroke and underwent IAT. They calculated individual HIAT and THRIVE scores using patient age, admission National Institutes of Health Stroke Scale (NIHSS) score, admission glucose level, and medical history. The scores' predictive accuracies for good outcome (discharge modified Rankin Scale score ≤ 3) were analyzed using receiver operating characteristics analysis. The THRIVE score predicts poor outcome after IAT with reasonable accuracy and may perform better than the HIAT score. Nevertheless, both measures may have significant clinical utility; further validation in larger cohorts that accounts for differences in patient demographic characteristics, variation in time-to-treatment, and center preferences with respect to IAT modalities is needed. Additional patient predictive factors have been reported but not yet incorporated into predictive scales; the authors suggest the need for additional data analysis to determine the independent predictive value of patient admission NIHSS score, age, admission hyperglycemia, patient comorbidities, thrombus burden, collateral flow, time to treatment, and baseline neuroimaging findings. PMID:21631231

  17. 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.

  18. 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.

  19. [Endovascular treatment for dural arteriovenous fistula].

    PubMed

    Miyachi, Shigeru

    2008-08-01

    Intracranial dural arteriovenous fistulas (DAVFs) are acquired abnormal epidural arteriovenous shunts, particularly at the sinus wall. Most of the DAVFs are associated with progressive sinus occlusion. They are located in the cavernous sinus, lateral (transverse-sigmoid) sinus, superior-sagittal sinus, anterior condylar confluence, tentorial sinus, craniocervical junction, and anterior skull base (ethmoidal sinus). The treatment strategy differs based on the etiology and drainage pattern of DAVFs. The most effective treatment for DAVFs at the sinus wall is transvenous embolization (TVE) with coils. The target coil packing is effective if the sinus point is identified. Certain cases that are difficult to approach transvenously are treated with transarterial embolization (TAE) by using liquid materials like such glue. In particular cases with sinus occlusive lesion sinus reconstruction with sinoplasty is effective. The cases with failed or impossible endovascular approach should be treated with surgical interruption of shunts or by radiosurgery. The most frequent complication of TAE is brain and nerve ischemia due to the overembolization or migration, and that in TVE is the bleeding due to obstruction of the drainage route and nerve compression due to overpacking of coils. PMID:18717194

  20. Reduction of aneurysm pressure and wall stress after endovascular repair of abdominal aortic aneurysm in a canine model.

    PubMed

    Marston, W A; Criado, E; Baird, C A; Keagy, B A

    1996-03-01

    A canine model was designed to evaluate the changes in abdominal aortic aneurysm (AAA) pressure and wall stress after endovascular repair. Eight canines underwent laparotomy and creation of an AAA. The aneurysm was then excluded with a transluminally placed endovascular graft (TPEG) inserted through the right femoral artery and deployed across the AAA to exclude the infrarenal aortic branches from aortic perfusion. Blood pressure and flow data were recorded for 6 hours. The AAA blood pressure decreased from 135 +/- 9.3 mm Hg before exclusion to 45 +/- 17.6 mm Hg at 10 minutes after exclusion (p < 0.001). At 6 hours, AAA blood pressure had declined further to 26 +/- 12.5 mm Hg. Blood flow in the excluded iliac artery decreased from a baseline of 242 +/- 58 ml/min to 41 +/- 29 ml/min 10 minutes after TPEG placement (p < 0.001). At 6 hours, flow was reduced to 12 +/- 3.5 ml/min (p < 0.05 compared with that at 10 minutes). Aortic wall stress was significantly reduced by TPEG placement but was only slightly lower than baseline aortic wall stress before AAA creation. The lumbar arteries were patent with retrograde flow in all cases and were found to be the major contributors to postexclusion aneurysm pressure. Endovascular AAA exclusion results in an immediate decrease in blood pressure and wall stress within the excluded aneurysm, but the aneurysm remains perfused by retrograde flow through the lumbar arteries, which resulted in near-baseline levels of aneurysm wall stress in this canine model. Embolization of patient lumbar vessels at prosthesis placement may further reduce the risk of late rupture. PMID:8733869

  1. 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

  2. Emerging Endovascular Therapies for Non-Compressible Torso Hemorrhage.

    PubMed

    Russo, Rachel M; Neff, Lucas P; Johnson, Michael Austin; Williams, Timothy K

    2016-09-01

    Management of non-compressible torso hemorrhage (NCTH) remains a challenge despite continued advancements in trauma resuscitation. Resuscitative thoracotomy with aortic cross-clamping and recent advances in endovascular aortic occlusion, including resuscitative endovascular occlusion of the aorta, have finite durations of therapy due to the inherent physiologic stressors that accompany complete occlusion. Here, we attempt to illuminate the current state of aortic occlusion for trauma resuscitation including explanation of the deleterious consequences of complete occlusion, potential methods and limitations of existing technology to overcome these consequences, and a description of innovative methods to improve the resuscitation of NCTH. By explaining the complexity and potential deleterious effects of resuscitation augmented with aortic occlusion, our goal is to provide practitioners with a real-world perspective on current endovascular technology and to encourage the continued innovation required to overcome existing obstacles. PMID:27172156

  3. 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

  4. [Repeat endovascular interventions after transjugular intrahepatic portosystemic shunt (tips) procedures].

    PubMed

    Shipovskiĭ, V N; Tsitsiashvili, M Sh; Saakian, A M; Monakhov, D V; Khuan, Ch; Nechaev, A I

    2010-01-01

    The authors share their experience with transjugular intrahepatic portosystemic shunt (TIPS) procedures preformed in a total of fifty-nine patients diagnosed with and hence operated on for class B and C hepatocirrhosis (according to the Child-Turcotte-Pugh classification), portal hypertension, grade 3 varicosely dilated oesophageal veins, or ascites. Of these, there were 12 women and 47 men (average age 56.3 years). Three types of stents were used: matrix stents (PERICO), self-expanding (ZA-stents, OptiMedsinus-SuperFlex- Visualstents, Zilverstents, SMART), and coated self-expanding stents (Gore Viatorr TIPS Endoprosthesis). Six (11 %) TIPS procedures ended in failure. Of the remaining 53 successful TIPS attempts, thirteen patients developed an in-stent thrombosis at various terms postoperatively, with one patient having experienced it twice Within four postoperative days, thrombosis occurred in three patients, at terms varying from one month to three months in five patients, and from 6 to 12 months in a further five patients. More often thromboses were encountered with the matrix stents (n = 3) 23.0% (PERICO) and self-expanding stents (n = 8) in 61.0% (OptiMed sinus-SuperFlex-Visual). Thromboses were clinically manifested by oesophageal variceal haemorrhage. An in-stent thrombosis was confirmed by means of ultrasonographic duplex scanning (lack of arterial blood flow). The primary stent patency rate following TIPS procedures amounted to 67%. with the secondary assisted graft patency rate equalling 89%. Restoration of the stent's lumen after TIPS procedures by means of endovascular recanalization, rheolytic thrombectomy, balloon angioplasty, and a stent-in-stent technique appears to be a minimally invasive, rather efficient method and virtually the only way to preserve the stent's patency. This technique makes it possible to decrease the rate of recurrent oesophageal variceal haemorrhage. PMID:21032871

  5. Pregnancy with a ruptured renal artery aneurysm: management concerns and endovascular management.

    PubMed

    Yadav, Siddharth; Sharma, Sanjay; Singh, Prabhjot; Nayak, Brusabhanu

    2015-01-01

    Renal artery aneurysm (RAA) affects <0.01% of the general population. Rupture of RAA is a rare catastrophe that can complicate pregnancy and is associated with high maternal and fetal mortality. Presentation is usually acute with severe flank pain, with or without haematuria, and haemodynamic instability requiring exploration and nephrectomy. A 26-year-old pregnant woman had sudden onset of gross haematuria and on evaluation was found to have a left RAA with an intrapelvic rupture and thinned out renal parenchyma. In view of the high risk of surgery, she was managed with endovascular placement of an Amplatzer type II vascular plug. Immediate and complete occlusion of blood flow was achieved and nephrectomy was avoided. Follow-up Doppler ultrasound revealed a reduced 5 cm mass in the left renal fossa with no internal flow and plug in position. She is currently on follow-up with 3-6 monthly ultrasonography not requiring any intervention. PMID:26504094

  6. Endovascular management of six simultaneous intracranial dural arteriovenous fistulas in a single patient

    PubMed Central

    Gist, Taylor L; Rangel-Castilla, Leonardo; Krishna, Chandan; Roman, Gustavo C; Cech, David A; Diaz, Orlando

    2013-01-01

    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. PMID:23475992

  7. Endovascular treatment of aortoiliac aneurysms: From intentional occlusion of the internal iliac artery to branch iliac stent graft

    PubMed Central

    Duvnjak, Stevo

    2016-01-01

    Approximately 20%-40% of patients with abdominal aortic aneurysms can have unilateral or bilateral iliac artery aneurysms and/or ectasia. This influences and compromises the distal sealing zone during endovascular aneurysm repair. There are a few endovascular techniques that are used to treat these types of aneurysms, including intentional occlusion/over-stenting of the internal iliac artery on one or both sides, the “bell-bottom” technique, and the more recent method of using an iliac branch stent graft. In some cases, other options include the “snorkel and sandwich” technique and hybrid interventions. Pelvic ischemia, represented as buttock claudication, has been reported in 16%-55% of cases; this is followed by impotence, which has been described in 10%-17% of cases following internal iliac artery occlusion. The bell-bottom technique can be used for a common iliac artery up to 24 mm in diameter given that the largest diameter of the stent graft is 28 mm. There is a paucity of data and evidence regarding the “snorkel and sandwich” technique, which can be used in a few clinical scenarios. The hybrid intervention is comprised of a surgical operation, and is not purely endovascular. The newest branch stent graft technology enables preservation of the anterograde flow of important side branches. Technical success with the newest technique ranges from 85%-96.3%, and in some small series, technical success is 100%. Buttock claudication was reported in up to 4% of patients treated with a branch stent graft at 5-year follow-up. Mid- and short-term follow-up results showed branch patency of up to 88% during the 5-6-year period. Furthermore, branch graft occlusion is a potential complication, and it has been described to occur in 1.2%-11% of cases. Iliac branch stent graft placement represents a further development in endovascular medicine, and it has a high technical success rate without serious complications. PMID:27027393

  8. Endovascular treatment of aortoiliac aneurysms: From intentional occlusion of the internal iliac artery to branch iliac stent graft.

    PubMed

    Duvnjak, Stevo

    2016-03-28

    Approximately 20%-40% of patients with abdominal aortic aneurysms can have unilateral or bilateral iliac artery aneurysms and/or ectasia. This influences and compromises the distal sealing zone during endovascular aneurysm repair. There are a few endovascular techniques that are used to treat these types of aneurysms, including intentional occlusion/over-stenting of the internal iliac artery on one or both sides, the "bell-bottom" technique, and the more recent method of using an iliac branch stent graft. In some cases, other options include the "snorkel and sandwich" technique and hybrid interventions. Pelvic ischemia, represented as buttock claudication, has been reported in 16%-55% of cases; this is followed by impotence, which has been described in 10%-17% of cases following internal iliac artery occlusion. The bell-bottom technique can be used for a common iliac artery up to 24 mm in diameter given that the largest diameter of the stent graft is 28 mm. There is a paucity of data and evidence regarding the "snorkel and sandwich" technique, which can be used in a few clinical scenarios. The hybrid intervention is comprised of a surgical operation, and is not purely endovascular. The newest branch stent graft technology enables preservation of the anterograde flow of important side branches. Technical success with the newest technique ranges from 85%-96.3%, and in some small series, technical success is 100%. Buttock claudication was reported in up to 4% of patients treated with a branch stent graft at 5-year follow-up. Mid- and short-term follow-up results showed branch patency of up to 88% during the 5-6-year period. Furthermore, branch graft occlusion is a potential complication, and it has been described to occur in 1.2%-11% of cases. Iliac branch stent graft placement represents a further development in endovascular medicine, and it has a high technical success rate without serious complications. PMID:27027393

  9. Endovascular treatments for posterior cerebral artery aneurysms and vascular insufficiency of fetal-type circulation after parent artery occlusion.

    PubMed

    Matsumura, Hideaki; Kato, Noriyuki; Fujiwara, Yusuke; Hosoo, Hisayuki; Yamazaki, Tomosato; Yasuda, Susumu; Matsumura, Akira

    2016-10-01

    We present a retrospective analysis of endovascular treatments for posterior cerebral artery (PCA) aneurysms and discuss the susceptibility of a fetal-type PCA to vascular insufficiency after parent artery occlusion. Among 1207 aneurysms treated with endovascular therapy between March 1997 and March 2013 in our institution, 10 patients (0.8%) presented PCA aneurysms. The principal strategy was to employ selective coil embolization for the aneurysm. However, in certain cases of fusiform or dissecting aneurysms, we performed parent artery occlusion with coils. Clinical and radiological data were collected from hospital charts and evaluated retrospectively. The mean age was 52.7±15.6years (range, 12-65years). Five patients (50%) were admitted with a subarachnoid hemorrhage, and one patient presented with slowly developing paralysis. The remaining four patients were diagnosed incidentally. Five patients underwent selective coil embolization, and five patients underwent parent artery occlusion. All endovascular therapies were successfully performed. However, two patients in the parent artery occlusion group suffered cerebral infarction, and both patients exhibited a fetal-type PCA. The remaining three patients in the parent artery occlusion group exhibited an adult-type PCA and did not suffer a cerebral infarction. Endovascular treatment with either selective coil embolization or parent artery occlusion is safe and effective as the long as the anatomical type of the PCA is considered. Patients with a fetal-type PCA may develop vascular insufficiency upon parent artery occlusion. Neurosurgeons should attempt to preserve the parent artery using a flow-diverting stent or stent-assisted technique for a fetal-type PCA aneurysm. PMID:27523585

  10. 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.

  11. Endovascular treatment of tracheoinnominate artery fistula: a case report.

    PubMed

    Palchik, Eugene; Bakken, Andrew M; Saad, Nael; Saad, Wael E; Davies, Mark G

    2007-01-01

    Tracheoinnominate fistula is a rare but lethal condition that requires emergent surgical intervention to prevent ensuing exsanguinating hemorrhage. In clinical situations where the risk of open surgery is prohibitively high, endovascular repair may provide a life-saving alternative to control hemorrhage and serve as a temporizing or definitive solution based on a given clinical scenario. The authors report successful endovascular repair of the bleeding tracheoinnominate fistula with a stent in a liver transplant patient with high comorbidities and review the current literature. PMID:17595395

  12. Endovascular Management of Anterior Cranial Fossa Dural Arteriovenous Malformations

    PubMed Central

    Mack, W.J; Gonzalez, N.R.; Jahan, R.; Vinuela, F.

    2011-01-01

    Summary Dural arteriovenous fistulas (dAVFs) of the anterior cranial fossa have traditionally been treated by open surgical disconnection. Safe navigation through the ophthalmic artery or fragile cortical veins has historically provided a barrier to effective endovascular occlusion of these lesions. Using current microcatheter technology and embolic materials, safe positioning within the distal ophthalmic artery, beyond the origin of the central retinal artery, is achievable. We describe two cases in which anterior cranial fossa dAVFs were treated by exclusively endovascular strategies, and highlight the pertinent technical and anatomic considerations. We discuss the clinical symptoms resulting from the differing venous drainage patterns. PMID:21561565

  13. 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. PMID:27521194

  14. Aneurysm growth after late conversion of thoracic endovascular aortic repair

    PubMed Central

    Hayashi, Ichiro; Haijima, Norimasa

    2015-01-01

    A 69-year-old man underwent thoracic endovascular aortic repair of a descending aortic aneurysm. Three years later, he developed impending rupture due to aneurysmal expansion that included the proximal landing zone. Urgent open surgery was performed via lateral thoracotomy, and a Dacron graft was sewn to the previous stent graft distally with Teflon felt reinforcement. Postoperatively, four sequential computed tomography scans demonstrated that the aneurysm was additionally increasing in size probably due to continuous hematoma production, suggesting a possibility of endoleaks. This case demonstrates the importance of careful radiologic surveillance after endovascular repair, and also after partial open conversion. PMID:27489673

  15. 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.

  16. Endovascular treatment of axillary artery dissection following anterior shoulder dislocation.

    PubMed

    Fass, G; Barchiche, M Reda; Lemaitre, J; De Quin, I; Goffin, C; Bricart, R; Bellens, B

    2008-01-01

    Injury to the axillary artery is a rare complication of anterior shoulder dislocation. Open surgical repair is technically demanding because of the anatomical position of the vessel and the propensity for concomitant injuries. Standard surgical exposure techniques involve extensive dissection, including a combination of supraclavicular or infraclavicular incision, median sternotomy, and thoracotomy causing significant morbidity and mortality rates. Endovascular techniques may offer an alternative to these surgically demanding procedures. We present a patient with a traumatic dissection of the axillary artery following anterior shoulder dislocation who was successfully managed with an endovascular stent. PMID:18411587

  17. Internal Carotid Artery Pseudoaneurysm after Tonsillectomy Treated by Endovascular Approach

    PubMed Central

    Raffin, C.N.; Montovani, J.C.; Neto, J.M.P.; Campos, C.M.S.; Piske, R.L.

    2002-01-01

    Summary Surgery on the head and neck region may be complicated by vascular trauma, caused by direct injury on the vascular wall. Lesions of the arteries are more dangerous than the venous one. The traumatic lesion may cause laceration of the artery wall, spasm, dissection, arteriovenous fistula, occlusion or pseudoaneurysm. We present a case of a child with a giant ICA pseudoaneurysm after tonsillectomy, manifested by pulsing mass and respiratory distress, which was treated by endovascular approach, occluding the lesion and the proximal artery with Histoacryl. We reinforce that the endovascular approach is the better way to treat most of the traumatic vascular lesions. PMID:20594516

  18. Clinical and morphological features of patients who underwent endovascular interventions for lower extremity arterial occlusive diseases

    PubMed Central

    Arslan, Sakir; Yuksel, Isa Oner; Koklu, Erkan; Cagirci, Goksel; Ureyen, Cagin Mustafa; Bayar, Nermin; Kus, Gorkem

    2015-01-01

    Introduction Patients with peripheral arterial disease (PAD) are at increased risk for all-cause mortality and cardiovascular mortality. Aim To present anatomical and morphological characteristics of patients who underwent endovascular stenting with laboratory and our mid-term results. Material and methods One hundred fifty-three patients (mean age: 62.8, 86% male) who underwent percutaneous intervention of lower extremity arteries were included in the study. Demographic characteristics, medical history, physical examination and laboratory findings of patients were analyzed. Patients’ lesions were classified according to the TransAtlantic Inter-Society Consensus (TASC). Clinical outcomes included complications and mortality, 6-minute walking distance, functional class (NYHA) and patency rates. Results Seventy percent of patients had hypertension, 42% were smokers, 78% had coronary artery disease, 20% had coronary artery bypass grafting, 55% had diabetes mellitus and 71% had dyslipidemia. Six patients with diabetes mellitus and poor wound healing despite medical therapy were treated with stenting leading to alleviation of pain and avoidance of amputation. The initial technical success rate of revascularization was 95.6% (153/160). Our mid-term results show that percutaneous procedures in lower extremity arterial diseases can be performed with low complication and high success rates. Patients’ 6-minute walk distance, ankle/brachial index values, functional class and the status of foot ulcers were evaluated. Conclusions Especially in patients with distal vascular disease, poor wound healing and no chance of surgical revascularization, percutaneous endovascular revascularization may provide good blood flow and prevent amputation. PMID:26161103

  19. 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.

  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. 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. PMID:26452902

  2. 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).

  3. Vascular access complications in endovascular procedures with large sheaths.

    PubMed

    Lejay, Anne; Caspar, Thibault; Ohana, Mickaël; Delay, Charline; Girsowicz, Elie; Ohlmann, P; Thaveau, Fabien; Geny, Bernard; Georg, Yannick; Chakfe, Nabil

    2016-04-01

    Endovascular procedures, such as transcatheter aortic valve implantation (TAVI), thoracic endovascular aortic repair (TEVAR), and endovascular abdominal aortic repair (EVAR) have been established as promising less invasive therapeutic options. However, despite continuous advances and device improvements, the use of large-sheaths still remains an important challenge, since significant coexisting arterial disease may be encountered in patients undergoing such procedures. Identification of coexisting arterial diseases by optimal preoperative imaging assessment is essential to anticipate these difficulties and avoid the complications by using adequate access options. Should a vascular complication such as iliac rupture occur, vascular interventionists must be aware of salvage procedures to control and treat major complications, such as maintaining wire access across the rupture for occlusion balloon placement and vessel control, while disruption is addressed either through an endovascular or an open approach. The aims of this review are to describe how to prevent vascular complications by optimal preoperative imaging assessment, to detail intraoperative options available for addressing difficult access issues and to discuss how to manage intraoperative major vascular complications. PMID:26603161

  4. Treatment of acute thoracic aortic syndromes using endovascular techniques

    PubMed Central

    Uğuz, Emrah; Canyiğit, Murat; Hıdıroğlu, Mete; Şener, Erol

    2016-01-01

    PURPOSE Acute thoracic aortic syndrome (ATAS) is a novel term to define emergency aortic conditions with common clinical features and challenges. Traditional management of ATAS includes surgical replacement of the aorta and is correlated with high perioperative mortality and morbidity. We aimed to evaluate our experience and outcomes in patients presenting with ATAS, managed by endovascular techniques. METHODS This cohort consisted of 31 consecutive patients (24 males; mean age, 57.5±13.81 years; range, 19–84 years) with acute thoracic aortic pathologies who underwent endovascular repair between January 2011 and January 2015. The study was designed as a retrospective analysis of prospectively maintained data. RESULTS Complicated acute type-B aortic dissection was the most common pathology (35.5%). All aortic stent-grafts (n=37) and dissection stents (n=9) were implanted with 100% procedural success. The overall in-hospital mortality was 9.7%. The mean follow-up duration of patients who were alive at 30 days was 25.9±11.49 months (3–53 months). So far, there have been no late deaths after 30 days. CONCLUSION In the high-risk setting of ATAS, endovascular procedures come forward as novel therapeutic strategies with promising results. Endovascular repair of ATAS can be considered as a first-line treatment alternative under emergency conditions with encouraging results, particularly when conventional surgical repair cannot be implemented due to prohibitive comorbidities. PMID:27113420

  5. 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.

  6. Salmonella aortitis treated with endovascular aortic repair: a case report

    PubMed Central

    2012-01-01

    Introduction Salmonella is a typical cause of aortitis, which is associated with high morbidity and mortality. In infrarenal disease, besides open surgery, endovascular aortic repair as an alternative treatment has been reported. To the best of our knowledge, we report the first successful endovascular aortic repair documented by necropsy to date. Case presentation A 67-year-old Caucasian man presented with low back pain, fever and positive blood cultures for Salmonella Enteritidis. A computed tomography scan showed an enlargement and intramural hematoma of the infrarenal aortic wall; a Salmonella aortitis was suspected and antimicrobial therapy initiated. Because of substantial comorbidities, endovascular aortic repair was favored over open surgery; postoperatively the antibiotic treatment was continued for 12 months. Post-mortem there were neither macroscopic nor microscopic signs of aortitis or graft infection. Conclusions We could demonstrate by necropsy that endovascular aortic repair of infrarenal aortitis with prolonged pre- and postinterventional antibiotic therapy for 12 months was a minimally invasive alternative and should be considered in selected clinically stable patients with substantial co-morbidities. PMID:22894684

  7. Endovascular Management of Diseases in Relation to Otolaryngology.

    PubMed

    Jovin, Tudor; Aghaebrahim, Amin

    2016-06-01

    Endovascular techniques can be utilized in many common otolaryngologic conditions. Advancements in in these techniques including but not limited to better distal access catheters, new embolization materials and stents allows this to be a relatively safe and successful procedure. Here we highlighted a few related procedures. PMID:27267030

  8. Pulmonary Hypertension in Hemodialysis Patients Following Repeated Endovascular Thrombectomy

    PubMed Central

    Hsieh, Mu-Yang; Lin, Lin; Chen, Tsung-Yan; Wang, Ren-Huei; Huang, Su-Chin; Liu, HsiuChiao; Lai, Chao-Lun; Pu, Shih-Yen; Tsai, Kuei-Chin; Wu, Chih-Cheng

    2016-01-01

    Background The prevalence of pulmonary hypertension is unusually high in Taiwanese patients with end-stage renal disease. Thrombosis of hemodialysis grafts is common and pulmonary embolism has been reported after endovascular thrombectomy. The aim of this study was to evaluate the relationship between pulmonary hypertension and endovascular thrombectomy of hemodialysis grafts. Methods One hundred and ten patients on hemodialysis via arteriovenous grafts were enrolled in our study. The mean pulmonary artery pressure (PAP) was measured by right heart catheterization. Clinical information was collected by review of medical records. Comorbid cardiopulmonary disease was evaluated by echocardiography and chest X-ray. The history of patient vascular access thrombosis was reviewed from database, hemodialysis records, and interviews with staff at hemodialysis centers. Results Fifty-two participants (47%) had pulmonary hypertension diagnosed by right heart catheterization. There was no difference in the number of thrombectomy procedures between patients with and without pulmonary hypertension. Based on multivariate analysis, the number of prior endovascular thrombectomy procedures did not correlate with mean PAP (F-value = 1.10, p = 0.30) nor was it associated with pulmonary hypertension (odds ratio = 0.92, p = 0.17). Conclusions Prior endovascular arteriovenous graft thrombectomies were not associated with pulmonary hypertension or increased mean PAP in end-stage renal disease patients on maintenance hemodialysis. PMID:27274170

  9. 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. PMID:25047700

  10. Endovascular Therapies for Primary Postpartum Hemorrhage: Techniques and Outcomes

    PubMed Central

    Gipson, Matthew G.; Smith, Mitchell T.

    2013-01-01

    Interventional radiologists are often consulted for acute management of hemorrhagic complications in obstetric and gynecologic patients. The aim of this article is to review the common indications for vascular embolization in obstetric and gynecologic emergencies, specifically in the setting of primary postpartum hemorrhage, and to discuss the technique and outcomes of endovascular treatment. PMID:24436559

  11. 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.

  12. Prognosis Predicting Score for Endovascular Treatment of Aneurysmal Subarachnoid Hemorrhage

    PubMed Central

    Duan, Guoli; Yang, Pengfei; Li, Qiang; Zuo, Qiao; Zhang, Lei; Hong, Bo; Xu, Yi; Zhao, Wenyuan; Liu, Jianmin; Huang, Qinghai

    2016-01-01

    Abstract The elderly patients with aneurysmal subarachnoid hemorrhage (aSAH) have a greater risk of poor clinical outcome after endovascular treatment (EVT) than younger patients do. Hence, it is necessary to explore which factors are associated with poor outcome and develop a predictive score specifically for elderly patients with aSAH receiving EVT. The aim of this study was to develop and validate a predictive score for 1-year outcomes in individual elderly patients with aSAH underwent EVT. In this 10-year prospective study, 520 consecutive aSAH elderly (age ≥ 60 years) patients underwent EVT in a single center were included. The risk factors, periprocedural, and 1-year follow-up data of all patients were entered in a specific prospective database. The modified Rankin scale was used for evaluating clinical outcome. To optimize the model's predictive capacity, the original matrix was randomly divided in 2 submatrices (learning and testing). The predictive score was developed using Arabic numerals for all variables based on the variable coefficients (β) of multivariable logistic regression analysis in the learning set and the predictive performance evaluation was assessed in the testing set. The risk classes were constructed using classification criteria based on sensitivity and specificity. The poor outcome rate at 1 year was 26.15%. Six risk factors, including age, hypertension, Hunt–Hess scale, Fisher scale, aneurysm location, and periprocedural complications, were independently associated with poor outcome and assembled the Changhai score. The discriminative power analysis with the area under the receiver operating characteristic curve (AUC) of the Changhai score was statistically significant (0.864, 0.824–0.904, P < 0.001). The sensitivity and specificity of the Changhai score were 82.07% and 78.06%, respectively. Our study indicated that age, hypertension, Hunt–Hess scale, Fisher scale, aneurysm location, and periprocedural complications were

  13. 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.

  14. Occupational Radiation Exposure During Endovascular Aortic Repair

    SciTech Connect

    Sailer, Anna M.; Schurink, Geert Willem H.; Bol, Martine E. Haan, Michiel W. de Zwam, Willem H. van Wildberger, Joachim E. Jeukens, Cécile R. L. P. N.

    2015-08-15

    PurposeThe aim of the study was to evaluate the radiation exposure to operating room personnel and to assess determinants for high personal doses during endovascular aortic repair.Materials and MethodsOccupational radiation exposure was prospectively evaluated during 22 infra-renal aortic repair procedures (EVAR), 11 thoracic aortic repair procedures (TEVAR), and 11 fenestrated or branched aortic repair procedures (FEVAR). Real-time over-lead dosimeters attached to the left breast pocket measured personal doses for the first operators (FO) and second operators (SO), radiology technicians (RT), scrub nurses (SN), anesthesiologists (AN), and non-sterile nurses (NSN). Besides protective apron and thyroid collar, no additional radiation shielding was used. Procedural dose area product (DAP), iodinated contrast volume, fluoroscopy time, patient’s body weight, and C-arm angulation were documented.ResultsAverage procedural FO dose was significantly higher during FEVAR (0.34 ± 0.28 mSv) compared to EVAR (0.11 ± 0.21 mSv) and TEVAR (0.06 ± 0.05 mSv; p = 0.003). Average personnel doses were 0.17 ± 0.21 mSv (FO), 0.042 ± 0.045 mSv (SO), 0.019 ± 0.042 mSv (RT), 0.017 ± 0.031 mSv (SN), 0.006 ± 0.007 mSv (AN), and 0.004 ± 0.009 mSv (NSN). SO and AN doses were strongly correlated with FO dose (p = 0.003 and p < 0.001). There was a significant correlation between FO dose and procedural DAP (R = 0.69, p < 0.001), iodinated contrast volume (R = 0.67, p < 0.001) and left-anterior C-arm projections >60° (p = 0.02), and a weak correlation with fluoroscopy time (R = 0.40, p = 0.049).ConclusionAverage FO dose was a factor four higher than SO dose. Predictors for high personal doses are procedural DAP, iodinated contrast volume, and left-anterior C-arm projections greater than 60°.

  15. Coil Embolization of Diverticulum of Kommerell: A Targeted Hybrid Endovascular Technique.

    PubMed

    Yu, Peter S Y; Yu, Simon C H; Ng, Cyrus T C; Kwok, Micky W T; Chow, Simon C Y; Ho, Jacky Y K; Underwood, Malcolm J; Wong, Randolph H L

    2016-05-01

    A 57-year-old man was incidentally found to have a dissected diverticulum of Kommerell originating from aberrant origin of right subclavian artery during follow-up for treated colon cancer. A right carotid-axillary bypass was followed by embolization of aberrant artery and the diverticulum by deployment of multiple detachable coils using the Penumbra Ruby System (Penumbra, Alameda, CA). Angiography after embolization showed exclusion of flow to the aberrant artery and a patent right carotid-axillary bypass. The patient recovered uneventfully and remained well for 12 weeks after the operation, without any complications. We believe this targeted endovascular approach can avoid complications related to the coverage of thoracic aorta and reduce the risk of access vessel trauma. PMID:27106460

  16. Large Diameter Limbs for Dilated Common Iliac Arteries in Endovascular Aneurysm Repair. Is It Safe?

    SciTech Connect

    Malagari, Katerina Brountzos, Elias; Gougoulakis, Alexandros; Papathanasiou, Matilda; Alexopoulou, Efthymia; Mastorakou, Renata; Kelekis, Dimitris

    2004-09-15

    In this prospective study we examined whether dilated common iliac arteries (CIAs) can provide a safe distal seal in endovascular aneurysm repair (EVAR) with the use of bifurcated stent grafts with large diameter limbs. Sixteen patients with 26 dilated CIAs with a diameter of {>=}6 mm who were offered EVAR using stent grafts with large diameter limbs were included in the study (Group A). Forty-two patients who also underwent EVAR without iliac dilatation, matched for age, sex and surgical risk were used for comparison (controls-Group B). In group A mean CIA diameter was 18.2 mm (16-28) and mean abdominal aortic aneurysm (AAA) diameter was 6.87 {+-} 1.05 cm; mean age was 77.2 {+-} 4.8 yrs (67-81). Mean follow-up was 33.6 months (2.8 yrs). CIA diameter changes and development of endoleaks were assessed by CT angiography (CTA). Overall iliac dilatation was present in 16/58 of our patients (27.6%). In 10 patients dilatation was bilateral (17.3%). Partial or complete flow to the internal iliac artery (IIA) territories was preserved in all patients post-EVAR. On follow-up, stable caliber of the dilated CIAs was observed in 21 patients (84%), enlargement of 1mm in 3 (16%), and failure of the distal attachment in 1 (6.2%). Compared to the control group there was no statistical significance in the incidence of complications. Dilated common iliac arteries provide a safe distal seal in patients who have undergone EVAR, thus obviating the need for additional endovascular procedures and sparing flow in the IIA vascular bed.

  17. Real-Time Magnetic Resonance-Guided Endovascular Repair of Experimental Abdominal Aortic Aneurysm in Swine

    PubMed Central

    Raman, Venkatesh K.; Karmarkar, Parag V.; Guttman, Michael A.; Dick, Alexander J.; Peters, Dana C.; Ozturk, Cengizhan; Pessanha, Breno S. S.; Thompson, Richard B.; Raval, Amish N.; DeSilva, Ranil; Aviles, Ronnier J.; Atalar, Ergin; McVeigh, Elliot R.; Lederman, Robert J.

    2005-01-01

    OBJECTIVES This study tested the hypotheses that endografts can be visualized and navigated in vivo solely under real-time magnetic resonance imaging (rtMRI) guidance to repair experimental abdominal aortic aneurysms (AAA) in swine, and that MRI can provide immediate assessment of endograft apposition and aneurysm exclusion. BACKGROUND Endovascular repair for AAA is limited by endoleak caused by inflow or outflow malapposition. The ability of rtMRI to image soft tissue and flow may improve on X-ray guidance of this procedure. METHODS Infrarenal AAA was created in swine by balloon overstretch. We used one passive commercial endograft, imaged based on metal-induced MRI artifacts, and several types of homemade active endografts, incorporating MRI receiver coils (antennae). Custom interactive rtMRI features included color coding the catheter-antenna signals individually, simultaneous multislice imaging, and real-time three-dimensional rendering. RESULTS Eleven repairs were performed solely using rtMRI, simultaneously depicting the device and soft-tissue pathology during endograft deployment. Active devices proved most useful. Intraprocedural MRI provided anatomic confirmation of stent strut apposition and functional corroboration of aneurysm exclusion and restoration of laminar flow in successful cases. In two cases, there was clear evidence of contrast accumulation in the aneurysm sac, denoting endoleak. CONCLUSIONS Endovascular AAA repair is feasible under rtMRI guidance. Active endografts facilitate device visualization and complement the soft tissue contrast afforded by MRI for precise positioning and deployment. Magnetic resonance imaging also permits immediate post-procedural anatomic and functional evaluation of successful aneurysm exclusion. PMID:15963411

  18. Aortic Arch Aneurysms: Treatment with Extra anatomical Bypass and Endovascular Stent-Grafting

    SciTech Connect

    Kato, Noriyuki; Shimono, Takatsugu; Hirano, Tadanori; Mizumoto, Toru; Ishida, Masaki; Fujii, Hideki; Yada, Isao; Takeda, Kan

    2002-10-15

    Endovascular repair of thoracic aortic aneurysms is emerging as an attractive alternative to surgical graft replacement. However,patients with aortic arch aneurysms are often excluded from the target of endovascular repair because of lack of suitable landing zones, especially at the proximal ones. In this paper we describe our method for treating patients with aortic arch aneurysms using a combination of extra anatomical bypass surgery and endovascular stent-grafting.

  19. Fenestrated Endovascular Grafts for the Repair of Juxtarenal Aortic Aneurysms

    PubMed Central

    2009-01-01

    Executive Summary Endovascular repair of abdominal aortic aneurysm (AAA) allows the exclusion of the dilated aneurismal segment of the aorta from the systematic circulation. The procedure requires, however, that the endograft extends to the healthy parts of the aorta above and below the aneurysm, yet the neck of a juxtarenal aortic aneurysm (JRA) is too short for a standard endovascular repair. Fenestrated endovascular aortic repair (f—EVAR) provides a solution to overcome this problem by enabling the continuation of blood flow to the renal and visceral arteries through holes or ‘fenestrations’ in the graft. These fenestrations are designed to match the ostial diameter of the renal and visceral arteries. There are three varieties fenestration, small, large, and scallop, and their location needs to be customized to fit the anatomy of the patient. If the device is not properly designed, if the alignment is inaccurate, or if the catheterization of the visceral arteries is not possible, the procedure may fail. In such cases, conversion to open surgery may become the only option as fenestrated endografts are not retrievable. It is recommended that a stent be placed within each small fenestration to the target artery to prevent shuttering of the artery or occlusion. Many authors have noted an increased risk of vessel occlusion in unstented fenestrations and scallops. Once placed in a patient, life-long follow-up at regular intervals is necessary to ensure the graft remains in its intended location, and that the components have adequate overlap. Should the need arise, routine follow-up allows the performance of timely and appropriate intervention through detection of events that could impact the long-term outcomes. Alternative Technology The technique of fenestrated endovascular grafting is still in evolution and few studies have been with published mid-term outcome data. As the technique become more common in vascular surgery practices, it will be important to

  20. Percutaneous Aspiration Thrombectomy for Arterial Thromboembolism during Infrainguinal Endovascular Recanalization

    PubMed Central

    Wei, Li-Ming; Zhu, Yue-Qi; Liu, Fang; Zhang, Pei-Lei; Li, Xiao-Cong; Zhao, Jun-Gong; Lu, Hai-Tao

    2015-01-01

    Objectives To evaluate the efficacy of percutaneous aspiration thrombectomy (PAT) for infrainguinal arterial thromboembolism in patients undergoing endovascular recanalization (EVR) and to investigate the predictors for thromboembolic complications. Materials and Methods In total, 23 patients (23 limbs) who underwent PAT for thromboembolism (PAT group, PG) during EVR and 237 patients (302 limbs) who underwent successful EVR without thromboembolic complications (control group, CG) were enrolled. Immediate post-operation and follow-up outcomes were compared between the two groups. Multivariate analysis was performed to identify the predictors of thromboembolic complications. Technical success of PAT was defined as achievement of <30% residual stenosis and restoration of mTIMI grade 3. Results The technical success rate was 95.7% in PG. After intervention, the ankle–brachial index (ABI), restoration of blood flow and improvement in dorsal/plantar arterial pulse score showed no significant differences between PG and CG. During follow-up in PG, a sustained ABI improvement was observed in 63.6% (70.9% in CG), an improvement in walking distance in 68.8% (79.9% in CG,), ulcer healing in 75.0% (71.7% in CG) and restenosis/occlusion in 31.8% (25.2% in CG). The limb salvage rate was 100% in PG (96.0% in CG), and pain relief was observed in 66.7% patients with critical limb ischaemia (81.6% in CG). Superficial femoral artery involvement [0.233; 95% confidence interval (CI), 0.108–0.461; P < 0.001], de-novo lesion occlusion (683.8; 95% CI, 36.5–12804.6; P < 0.001) and intraluminal angioplasty (118.4; 95% CI, 8.0–1758.0; P = 0.001) was associated with high incidence of thromboembolism. Conclusion PAT is a safe and effective treatment for thromboembolism during infrainguinal arterial EVR. SFA involvement, de-novo lesion occlusion and intraluminal angioplasty may be predictors of thromboembolic complications. PMID:26484672

  1. 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.

  2. Endovascular Management of Post-Irradiated Carotid Blowout Syndrome

    PubMed Central

    Chang, Feng-Chi; Luo, Chao-Bao; Lirng, Jiing-Feng; Lin, Chung-Jung; Lee, Han-Jui; Wu, Chih-Chun; Hung, Sheng-Che; Guo, Wan-Yuo

    2015-01-01

    Purpose To retrospectively evaluate the clinical and technical factors related to the outcomes of endovascular management in patients with head-and-neck cancers associated with post-irradiated carotid blowout syndrome (PCBS). Materials and Methods Between 2000 and 2013, 96 patients with PCBS underwent endovascular management. The 40 patients with the pathological lesions located in the external carotid artery were classified as group 1 and were treated with embolization. The other 56 patients with the pathological lesions located in the trunk of the carotid artery were divided into 2 groups as follows: group 2A comprised the 38 patients treated with embolization, and group 2B comprised the 18 patients treated with stent-graft placement. Fisher’s exact test was used to examine endovascular methods, clinical severities, and postprocedural clinical diseases as predictors of outcomes. Results Technical success and immediate hemostasis were achieved in all patients. The results according to endovascular methods (group 1 vs 2A vs 2B) were as follows: technical complication (1/40[2.5%] vs 9/38[23.7%] vs 9/18[50.0%], P = 0.0001); rebleeding (14/40[35.0%] vs 5/38[13.2%] vs 7/18[38.9%]), P = 0.0435). The results according to clinical severity (acute vs ongoing PCBS) were as follows: technical complication (15/47[31.9%] vs 4/49[8.2%], P = 0.0035); rebleeding (18/47[38.3%] vs 8/49[16.3%], P = 0.0155). The results according to post-procedural clinical disease (regressive vs progressive change) were as follows: alive (14/21[66.7%] vs 8/75[10.7%], P<0.0001); survival time (34.1±30.6[0.3–110] vs 3.6±4.0[0.07–22] months, P<0.0001). Conclusion The outcomes of endovascular management of PCBS can be improved by taking embolization as a prior way of treatment, performing endovascular intervention in slight clinical severity and aggressive management of the post-procedural clinical disease. PMID:26439632

  3. 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.

  4. Standard of Practice for the Endovascular Treatment of Thoracic Aortic Aneurysms and Type B Dissections

    SciTech Connect

    Fanelli, Fabrizio; Dake, Michael D.

    2009-09-15

    Thoracic endovascular aortic repair (TEVAR) represents a minimally invasive technique alternative to conventional open surgical reconstruction for the treatment of thoracic aortic pathologies. Rapid advances in endovascular technology and procedural breakthroughs have contributed to a dramatic transformation of the entire field of thoracic aortic surgery. TEVAR procedures can be challenging and, at times, extraordinarily difficult. They require seasoned endovascular experience and refined skills. Of all endovascular procedures, meticulous assessment of anatomy and preoperative procedure planning are absolutely paramount to produce optimal outcomes. These guidelines are intended for use in quality-improvement programs that assess the standard of care expected from all physicians who perform TEVAR procedures.

  5. Toward the calculation of flows of a one-velocity multicomponent mixture by the modified S. K. Godunov method

    NASA Astrophysics Data System (ADS)

    Surov, V. S.

    2011-07-01

    Different variants of the Godunov method that describe the flow of a one-velocity multicomponent mixture for nondivergent systems are compared. In calculation of the Riemann problems, an approximate method of computations based on the characteristic relations was employed.

  6. Procedural Predictors of Outcome in Patients Undergoing Endovascular Therapy for Acute Ischemic Stroke

    SciTech Connect

    Rai, Ansaar T. Jhadhav, Yahodeep; Domico, Jennifer; Hobbs, Gerald R.

    2012-12-15

    Purpose: To identify factors impacting outcome in patients undergoing interventions for acute ischemic stroke (AIS). Materials and Methods: This was a retrospective analysis of patients undergoing endovascular therapy for AIS secondary during a 30 month period. Outcome was based on modified Rankin score at 3- to 6-month follow-up. Recanalization was defined as Thrombolysis in myocardial infarction score 2 to 3. Collaterals were graded based on pial circulation from the anterior cerebral artery either from an ipsilateral injection in cases of middle cerebral artery (MCA) occlusion or contralateral injection for internal carotid artery terminus (ICA) occlusion as follows: no collaterals (grade 0), some collaterals with retrograde opacification of the distal MCA territory (grade 1), and good collaterals with filling of the proximal MCA (M2) branches or retrograde opacification up to the occlusion site (grade 2). Occlusion site was divided into group 1 (ICA), group 2 (MCA with or without contiguous M2 involvement), and group 3 (isolated M2 or M3 branch occlusion). Results: A total of 89 patients were studied. Median age and National Institutes of health stroke scale (NIHSS) score was 71 and 15 years, respectively. Favorable outcome was seen in 49.4% of patients and mortality in 25.8% of patients. Younger age (P = 0.006), lower baseline NIHSS score (P = 0.001), successful recanalization (P < 0.0001), collateral support (P = 0.0008), distal occlusion (P = 0.001), and shorter procedure duration (P = 0.01) were associated with a favorable outcome. Factors affecting successful recanalization included younger age (P = 0.01), lower baseline NIHSS score (P = 0.05), collateral support (P = 0.01), and shorter procedure duration (P = 0.03). An ICA terminus occlusion (P < 0.0001), lack of collaterals (P = 0.0003), and unsuccessful recanalization (P = 0.005) were significantly associated with mortality. Conclusion: Angiographic findings and preprocedure variables can help

  7. Endovascular ischemic stroke models of adult rhesus monkeys: a comparison of two endovascular methods.

    PubMed

    Wu, Di; Chen, Jian; Wang, Bincheng; Zhang, Mo; Shi, Jingfei; Ma, Yanhui; Zhu, Zixin; Yan, Feng; He, Xiaoduo; Li, Shengli; Dornbos Iii, David; Ding, Yuchuan; Ji, Xunming

    2016-01-01

    To further investigate and improve upon current stroke models in nonhuman primates, infarct size, neurologic function and survival were evaluated in two endovascular ischemic models in sixteen rhesus monkeys. The first method utilized a micro-catheter or an inflatable balloon to occlude the M1 segment in six monkeys. In the second model, an autologous clot was injected via a micro-catheter into the M1 segment in ten monkeys. MRI scanning was performed on all monkeys both at baseline and 3 hours after the onset of ischemia. Spetzler neurologic functions were assessed post-operatively, and selective perfusion deficits were confirmed by DSA and MRI in all monkeys. Animals undergoing micro-catheter or balloon occlusion demonstrated more profound hemiparesis, larger infarct sizes, lower Spetzler neurologic scores and increased mortality compared to the thrombus occlusion group. In animals injected with the clot, there was no evidence of dissolution, and the thrombus was either near the injection site (M1) or flushed into the superior division of the MCA (M2). All animals survived the M2 occlusion. M1 occlusion with thrombus generated 50% mortality. This study highlighted clinically important differences in these two models, providing a platform for further study of a translational thromboembolic model of acute ischemic stroke. PMID:27534985

  8. Endovascular ischemic stroke models of adult rhesus monkeys: a comparison of two endovascular methods

    PubMed Central

    Wu, Di; Chen, Jian; Wang, Bincheng; Zhang, Mo; Shi, Jingfei; Ma, Yanhui; Zhu, Zixin; Yan, Feng; He, Xiaoduo; Li, Shengli; Dornbos III, David; Ding, Yuchuan; Ji, Xunming

    2016-01-01

    To further investigate and improve upon current stroke models in nonhuman primates, infarct size, neurologic function and survival were evaluated in two endovascular ischemic models in sixteen rhesus monkeys. The first method utilized a micro-catheter or an inflatable balloon to occlude the M1 segment in six monkeys. In the second model, an autologous clot was injected via a micro-catheter into the M1 segment in ten monkeys. MRI scanning was performed on all monkeys both at baseline and 3 hours after the onset of ischemia. Spetzler neurologic functions were assessed post-operatively, and selective perfusion deficits were confirmed by DSA and MRI in all monkeys. Animals undergoing micro-catheter or balloon occlusion demonstrated more profound hemiparesis, larger infarct sizes, lower Spetzler neurologic scores and increased mortality compared to the thrombus occlusion group. In animals injected with the clot, there was no evidence of dissolution, and the thrombus was either near the injection site (M1) or flushed into the superior division of the MCA (M2). All animals survived the M2 occlusion. M1 occlusion with thrombus generated 50% mortality. This study highlighted clinically important differences in these two models, providing a platform for further study of a translational thromboembolic model of acute ischemic stroke. PMID:27534985

  9. Endovascular repair of aortic disease: a venture capital perspective.

    PubMed

    Buchanan, Lucas W; Stavropoulos, S William; Resnick, Joshua B; Solomon, Jeffrey

    2009-03-01

    Endovascular devices for the treatment of abdominal and thoracic aortic disease are poised to become the next $1 billion medical device market. A shift from open repair to endovascular repair, advances in technology, screening initiatives, and new indications are driving this growth. Although billion-dollar medical device markets are rare, this field is fraught with risk and uncertainty for startups and their venture capital investors. Technological hurdles, daunting clinical and regulatory timelines, market adoption issues, and entrenched competitors pose significant barriers to successful new venture creation. In fact, the number of aortic endografts that have failed to reach commercialization or have been pulled from the market exceeds the number of Food and Drug Administration-approved endografts in the United States. This article will shed some light on the venture capital mind-set and decision-making paradigm in the context of aortic disease. PMID:21326532

  10. Lethal Hemorrhage Caused by Aortoenteric Fistula Following Endovascular Stent Implantation

    SciTech Connect

    Kahlke, Volker; Brossmann, Joachim; Klomp, Hans-Juergen

    2002-06-15

    A 55-year-old women developed an aortointestinal fistula between the bifurcation of the aorta and the distal ileum following implantation of multiple endovascular stents into both common iliac arteries for treatment of aortoiliac occlusive disease. Ten months before the acute onset of the gastrointestinal hemorrhage two balloon-expandable steel stents had been implanted into both common iliac arteries. Due to restenosis and recurrent intermittent claudication, three balloon-expandable covered stents were implanted 4 months later on reintervention. The patient presented with abdominal pain and melena, and fell into hemorrhagic shock with signs of upper gastrointestinal bleeding. After transfer to our hospital, she again developed hemorrhagic shock with massive upper and lower gastrointestinal bleeding and died during emergency laparotomy. The development of aortoenteric fistulas following endovascular surgery/stent implantation is very rare and has to be considered in cases of acute gastrointestinal hemorrhage.

  11. [Endovascular repair of iliocaval arteriovenous fistula complicating lumbar disc surgery].

    PubMed

    Ben Jemaa, H; Maalej, A; Lazzez, K; Jemal, H; Karray, S; Ben Mahfoudh, K

    2016-05-01

    Vascular complications of lumbar disc surgery are rare. Few cases have been reported. Arteriovenous fistulas are the most common. They are due to anatomical relationships between the last lumbar vertebrae, the corresponding discs, and the iliac vessels; degenerative lesions of the intervertebral discs facilitate instrumental vessel perforation, and operative difficulty. Computed tomography is particularly accurate for making the diagnosis. Treatment strategies consist in surgery or endovascular management. Percutaneous endovascular treatment using a stent-graft is a reasonable option for treating arteriovenous fistula. We describe the case of a 50-year-old patient who developed an iliocaval arteriovenous fistula following lumbar disc hernia surgery. The lesion was excluded by a stent-graft. The postoperative period was uneventful. PMID:26920402

  12. Endovascular Treatment of Acute Thrombosis of Cerebral Veins and Sinuses

    PubMed Central

    Yakovlev, Sergey Borisovich; Bocharov, Aleksei Vasilievich; Mikeladze, Ketevan; Gasparian, Sergey Surenovich; Serova, Natalia Konstantinovna; Shakhnovich, Alexander Romanovich

    2014-01-01

    Summary Acute thrombosis of cerebral veins and sinuses (ATCVS) is a multifactorial disease with grave consequences. Because of its rare occurrence there are no proven treatment guidelines. Sixteen patients with ATCVS were treated. The final diagnosis was confirmed by digital subtraction angiography. Sinus catheterization was performed via transfemoral venous access. Treatment included mechanical manipulation of thrombi and thrombolytic therapy. A regression of clinical symptoms with a concomitant decrease of intracranial hypertension was achieved in all patients. Long-term results were studied in eight patients: none presented clinical signs of intracranial hypertension. Endovascular transvenous recanalization is an effective treatment for acute thrombosis of cerebral veins and sinuses. Along with the local thrombolysis, significant potential in the treatment of this complex pathology lies in the transvenous endovascular techniques of mechanical thrombus extraction, especially in patients with intracranial hemorrhage for whom the use of thrombolytic agents is restricted. PMID:25196622

  13. Endovascular Versus Medical Therapy for Atherosclerotic Renovascular Disease

    PubMed Central

    Yu, Mark Shipeng; Folt, David A.; Drummond, Christopher A.; Haller, Steven T.; Cooper, Emily L.; Brewster, Pamela; Evans, Kaleigh L.

    2016-01-01

    The diagnosis of renal artery stenosis (RAS) has become increasingly common in part due to greater awareness of ischemic renal disease and increased use of diagnostic techniques. Over 90 % of RAS cases are caused by atherosclerotic renovascular disease (ARVD). Patients with ARVD are at high risk for fatal and nonfatal cardiovascular and renal events. The mortality rate in patients with ARVD is high, especially with other cardiovascular or renal comorbidities. Recent clinical studies have provided substantial evidence concerning medical therapy and endovascular interventional therapeutic approaches for ARVD. Despite previous randomized clinical trials, the optimal therapy for ARVD remained uncertain until the results of the Cardiovascular Outcomes in Renal Atherosclerotic Lesions (CORAL) trial were released recently. CORAL demonstrated that optimal medical therapy was equally effective to endovascular therapy in the treatment of ARVD. Clinicians can now practice with more evidence-based medicine to treat ARVD and potentially decrease mortality in patients with ARVD using optimal medical therapy. PMID:25301353

  14. Endovascular treatment of multiple aneurysms complicating Cogan syndrome.

    PubMed

    Angiletta, Domenico; Wiesel, Paola; Pulli, Raffaele; Marinazzo, Davide; Bortone, Alessandro Santo; Regina, Guido

    2015-02-01

    To report the use of endografts to manage multiple aneurysms due to Cogan syndrome (CS). A 38-year-old woman with descending thoracic aorta and right common carotid artery aneurysms due to CS was treated with endovascular grafts. After 4 years, angio computed tomography scan demonstrated complete exclusion of the aneurysms with no signs of endoleak, whereas echo color Doppler showed patency of the carotid graft, no signs of restenosis, no progression of the disease in the landing zones, and complete aneurysm exclusion. Endovascular repair seems to have favorable long-term outcomes and should be considered a viable alternative to surgery in unfit for open surgery patients, even if they are young, and when the aneurysm size and location would pose a higher risk of perioperative and postoperative complications after an open surgical procedure. PMID:25462550

  15. [Thoracic Endovascular Aortic Repair Via Internal Iliac Artery Conduit].

    PubMed

    Hayashi, Taro; Tobe, Satoshi; Sugiyama, Hironobu; Ijyuin, Shinichi; Yamaguchi, Masahiro; Yamaguchi, Masato; Oka, Takanori; Misato, Takuya; Tsunemi, Kotaro; Tanimura, Nobuhiro

    2016-09-01

    A 77-year-old man with a history of stent implantation in the right common iliac artery(CIA) and the left external iliac artery(EIA) was admitted to our hospital for a rapid growth of an aneurysm( max 53 mm) at Th11 level of the descending aorta. Although thoracic endovascular aortic repair (TEVAR) was required, there were many problems about access rout. The infrarenal abdominal aorta and the left EIA were severely calcified, and the lumens of the right CIA stent(5.3 mm) and the left EIA stent( 4.3 mm) were small in size. Besides, the left CIA was short(13 mm). Therefore, TEVAR was performed by retrograde approach from the left internal iliac artery( IIA) with a tube graft conduit in the hybrid operation room. IIA is a useful option for an access rout in endovascular aortic repair. PMID:27586313

  16. Assessment of periprocedural hemodynamic changes in arteriovenous malformation vessels by endovascular dual-sensor guidewire.

    PubMed

    Orlov, Kirill; Panarin, Vyacheslav; Krivoshapkin, Alexey; Kislitsin, Dmitry; Berestov, Vadim; Shayakhmetov, Timur; Gorbatykh, Anton

    2015-02-01

    Endovascular embolization is an important modality in the treatment of brain AVMs. Nowadays staged embolization is the method of choice for the prevention of perioperative hemorrhagic complications. Current theory suggests that simultaneous occlusion of more than 60% of AVM volume induces significant redistribution local blood flow. That, in turn, may lead to hemorrhage due to AVM rupture. Aside from angiographic findings, there is still no method that predicts the degree of safe partial embolization. Intraluminal measurement of flow velocity and pressure in the vicinity of the AVM nidus might allow detecting the changes in local hemodynamics. That can provide a valuable data and shed the light on the origin of vascular catastrophes. Ten patients underwent 12 embolization sessions with intraluminal flow velocity and pressure monitoring. The measurements were performed by dual-sensor guidewire. The "Combomap" (Volcano) system with Combowire microguidewires was chosen for measurements, as there is a documented experience of safe use of said guidewires in the cerebral vasculature. The findings observed during the study matched empirical data as well as the current physiological hypothesis of AVM hemorrhage. In conjunction with DSA runs, intraluminal flow velocity and pressure monitoring has the potential to become a valuable tool in AVM treatment. PMID:25934783

  17. Carotid Stump Syndrome: Pathophysiology and Endovascular Treatment Options

    SciTech Connect

    Lakshminarayan, Raghuram; Scott, Paul M.; Robinson, Graham J.; Ettles, Duncan F.

    2011-02-15

    Carotid stump syndrome is one of the recognised causes of recurrent ipsilateral cerebrovascular events after occlusion of the internal carotid artery. It is believed that microemboli arising from the stump of the occluded internal carotid artery or the ipsilateral external carotid artery can pass into the middle cerebral artery circulation as a result of patent external carotid-internal carotid anastomotic channels. Different pathophysiologic causes of this syndrome and endovascular options for treatment are discussed.

  18. Endovascular Treatment of Extracranial Internal Carotid Aneurysms Using Endografts

    SciTech Connect

    Baldi, Sebastian Rostagno, Roman D.; Zander, Tobias; Llorens, Rafael; Schonholz, Claudio; Maynar, Manuel

    2008-03-15

    Aneurysms of the extracranial internal carotid artery (EICA) are infrequent. They are difficult to treat with conventional surgery because of their distal extension into the skull base. We report three cases of EICA aneurysms in two symptomatic patients successfully treated with polytetrafluoroethylene self-expanding endografts using an endovascular approach. The aneurysms were located distal to the carotid bifurcation and extended to the subpetrous portion of the internal carotid artery.

  19. Emergency Endovascular Treatment of Abdominal Aortic Aneurysms: Feasibility and Results

    SciTech Connect

    Lagana, Domenico Carrafiello, Gianpaolo; Mangini, Monica; Fontana, Federico; Caronno, Roberto; Castelli, Patrizio; Cuffari, Salvatore; Fugazzola, Carlo

    2006-04-15

    Purpose. To assess the feasibility and effectiveness of emergency endovascular treatment of abdominal aortic aneurysms (AAAs). Methods. During 36 months we treated, on an emergency basis, 30 AAAs with endovascular exclusion. In 21 hemodynamically stable patients preoperative CT angiography (CTA) was performed to confirm the diagnosis and to plan the treatment; 9 patients with hemorrhagic shock were evaluated with angiography performed in the operating room. Twenty-two Excluder (Gore) and 8 Zenith (Cook) stent-grafts (25 bifurcated and 5 aorto-uni-iliac) were used. The follow-up was performed by CTA at 1, 3, 6, and 12 months. Results. Technical success was achieved in 100% of cases with a 10% mortality rate. The total complication rate was 23% (5 increases in serum creatinine level and 2 wound infections). During the follow-up, performed in 27 patients (1-36 months, mean 15.2 months), 4 secondary endoleaks (15%) (3 type II, 2 spontaneously thrombosed and 1 under observation, and 1 type III treated by iliac extender insertion) and 1 iliac leg occlusion (treated with femoro-femoral bypass) occurred. We observed a shrinkage of the aneurysmal sac in 8 of 27 cases and stability in 19 of 27 cases; we did not observe any endotension. Conclusions. Endovascular repair is a good option for emergency treatment of AAAs. The team's experience allows correct planning of the procedure in emergency situations also, with technical results comparable with elective repair. In our experience the bifurcated stent-graft is the device of choice in patients with suitable anatomy because the procedure is less time-consuming than aorto-uni-iliac stent-grafting with surgical crossover, allowing faster aneurysm exclusion. However, further studies are required to demonstrate the long-term efficacy of endovascular repair compared with surgical treatment.

  20. Emergency Endovascular 'Bridge' Treatment for Iliac-Enteric Fistula

    SciTech Connect

    Franchin, Marco; Tozzi, Matteo; Piffaretti, Gabriele; Carrafiello, Gianpaolo; Castelli, Patrizio

    2011-10-15

    Aortic aneurysm has been reported to be the dominant cause of primary iliac-enteric fistula (IEF) in >70% of cases [1]; other less common causes of primary IEF include peptic ulcer, primary aortitis, pancreatic pseudocyst, or neoplastic erosion into an adjacent artery [2, 3]. We describe an unusual case of IEF managed with a staged approach using an endovascular stent-graft as a 'bridge' in the emergency setting to optimize the next elective definitive excision of the lesion.

  1. Endovascular treatment of blunt traumatic thoracic aortic injury.

    PubMed

    Nicolaou, Georghios

    2009-06-01

    Blunt traumatic thoracic aortic injury (BTTAI) is a lethal injury associated with a prehospital mortality of 80% to 90%. Patients arriving in the emergency room and considered appropriate to undergo emergency open surgical repair still have a mortality rate of 15% to 30% because of severe associated injuries. Conventional open surgical repair requires a left thoracotomy, single lung ventilation, aortic-cross clamping and unclamping, with or without the adjunct use of partial or full cardiopulmonary bypass and systemic heparinization. All this leads to significant physiological stress and surgical trauma resulting in perioperative complications such as major blood loss, coagulopathy, myocardial infarction, stroke, respiratory failure, renal failure, bowel infarction, and paraplegia. Despite advances in anesthesia, critical care medicine, and surgical techniques, a recent meta-analysis showed no definite improvement in operative mortality over the past decade, following open surgical repair in patients with BTTAI. Endovascular repair of BTTAI does not require a thoracotomy, single lung ventilation, aorticcross clamping and unclamping, or systemic heparinization. As a result, endovascular repair of BTTAI has emerged as an effective, minimally invasive treatment alternative, especially in patients with severe concomitant injuries, which may be prohibitive to open surgical repair. Recent published studies have shown that endovascular repair of BTTAI is associated with lower morbidity, mortality, stroke, and paraplegia/paraparesis rates, when compared with open surgical repair of BTTAI. PMID:19617250

  2. Endovascular Management of Iatrogenic Native Renal Arterial Pseudoaneurysms

    SciTech Connect

    Sildiroglu, Onur; Saad, Wael E.; Hagspiel, Klaus D.; Matsumoto, Alan H.; Turba, Ulku Cenk

    2012-12-15

    Purpose: Our purpose was to evaluate iatrogenic renal pseudoaneurysms, endovascular treatment, and outcomes. Methods: This retrospective study (2003-2011) reported the technical and clinical outcomes of endovascular therapy for renal pseudoaneurysms in eight patients (mean age, 46 (range 24-68) years). Renal parenchymal loss evaluation was based on digital subtraction angiography and computed tomography. Results: We identified eight iatrogenic renal pseudoaneurysm patients with symptoms of hematuria, pain, and hematoma after renal biopsy (n = 3), surgery (n = 3), percutaneous nephrolithotomy (n = 1), and endoscopic shock-wave lithotripsy (n = 1). In six patients, the pseudoaneurysms were small-sized (<20 mm) and peripherally located and were treated solely with coil embolization (n = 5). In one patient, coil embolization was preceded by embolization with 500-700 micron embospheres to control active bleeding. The remaining two patients had large-sized ({>=}50 mm), centrally located renal pseudoaneurysms treated with thrombin {+-} coils. Technical success with immediate bleeding cessation was achieved in all patients. There were no procedure-related deaths or complications (mean follow-up, 23.5 (range, 1-67) months). Conclusions: Treatment of renal pseudoaneurysms using endovascular approach is a relatively safe and viable option regardless of location (central or peripheral) and size of the lesions with minimal renal parenchymal sacrifice.

  3. Carotid Stump Syndrome: Case Report and Endovascular Treatment.

    PubMed

    Dakhoul, Lara Toufic; Tawk, Rabih

    2014-01-01

    Objectives. To highlight the case of a patient with multiple transient ischemic attacks and visual disturbances diagnosed with carotid stump syndrome and managed with endovascular approach. Case Presentation. We present the case of a carotid stump syndrome in an elderly patient found to have moderate left internal carotid artery stenosis in response to an advertisement for carotid screening. After a medical therapeutic approach and a close follow-up, transient ischemic attacks recurred. Computed tomographic angiography showed an occlusion of the left internal carotid artery and the presence of moderate stenosis in the right internal carotid artery, which was treated by endovascular stenting and balloon insertion. One month later, the patient presented with visual disturbances due to the left carotid stump and severe stenosis of the left external carotid artery that was reapproached by endovascular stenting. Conclusion. Considerations should be given to the carotid stump syndrome as a source of emboli for ischemic strokes, and vascular assessment could be used to detect and treat this syndrome. PMID:26425620

  4. Endovascular Embolization of Brain Arteriovenous Malformations with Eudragit-E

    PubMed Central

    TAMURA, Goichiro; KATO, Noriyuki; YAMAZAKI, Tomosato; AKUTSU, Yoshimitsu; HOSOO, Hisayuki; KASUYA, Hiromichi; SONOBE, Makoto

    2015-01-01

    Eudragit-E was originally developed as a non-adhesive liquid embolic material in the late 1990s and is a copolymer of methyl and butyl methacrylate and dimethylaminoethyl methacrylate that is dissolved in ethanol and iopamidol. This material has been used for endovascular embolization of brain arteriovenous malformations (AVMs) for some time but is currently not widely used. Because safety and feasibility of Eudragit-E has not been well documented, we here report our experience using this material for treating 22 human brain AVMs. From June 1998 to February 2014, 30 endovascular procedures using Eudragit-E were performed to treat 22 patients, including 14 men and 8 women with a mean age of 41.1 years (15–70 years). The mean follow-up period was 56 months (12–129 months), and the Spetzler-Martin grades were I (4 patients), II (9 patients), III (5 patients), and IV (4 patients). Residual AVMs were treated with stereotactic radiosurgery or surgery. The rate of complete obliteration with embolization alone was 27.3%. The overall obliteration rate after endovascular embolization with/without subsequent stereotactic radiosurgery or surgery was 72.7%. Eudragit-E caused two cases of cerebral infarction. One case of intracerebral hemorrhage due to postoperative hemodynamic changes also occurred. The rate of complications directly related to embolization was 10.0%. The safety and effectiveness of Eudragit-E embolization were satisfactory. PMID:25739432

  5. Endovascular Treatment of Ruptured Abdominal Aortic Aneurysm with Aortocaval Fistula

    SciTech Connect

    Guzzardi, Giuseppe Fossaceca, Rita; Divenuto, Ignazio; Musiani, Antonello; Brustia, Piero; Carriero, Alessandro

    2010-08-15

    Aortocaval fistula (ACF) is a rare complication of abdominal aortic aneurysm (AAA). We report the endovascular repair of an AAA rupture into the inferior vena cava. A 78-year-old woman was admitted to our hospital for acute hypotension. She presented with a pulsatile abdominal mass and became rapidly anuric. Abdominal computed tomography (CT) showed an AAA rupture into the inferior vena cava. The features of the AAA made it suitable for endovascular repair. To prevent pulmonary embolism caused by the presence of sac thrombosis near the vena cava lumen, a temporary vena cava filter was deployed before the procedure. A bifurcated stent-graft was placed with the patient under local anaesthesia, and the AAA was successfully treated. A transient type II endoleak was detected on CT 3 days after endograft placement. At routine follow-up 6 and 12 months after the procedure, the patient was in good clinical condition, and the type II endoleak had sealed completely. Endovascular treatment offers an attractive therapeutic alternative to open repair in case of ACF; however, only small numbers of patients have been treated, and long-term follow-up interval is lacking.

  6. Endovascular embolization of brain arteriovenous malformations with Eudragit-E.

    PubMed

    Tamura, Goichiro; Kato, Noriyuki; Yamazaki, Tomosato; Akutsu, Yoshimitsu; Hosoo, Hisayuki; Kasuya, Hiromichi; Sonobe, Makoto

    2015-01-01

    Eudragit-E was originally developed as a non-adhesive liquid embolic material in the late 1990s and is a copolymer of methyl and butyl methacrylate and dimethylaminoethyl methacrylate that is dissolved in ethanol and iopamidol. This material has been used for endovascular embolization of brain arteriovenous malformations (AVMs) for some time but is currently not widely used. Because safety and feasibility of Eudragit-E has not been well documented, we here report our experience using this material for treating 22 human brain AVMs. From June 1998 to February 2014, 30 endovascular procedures using Eudragit-E were performed to treat 22 patients, including 14 men and 8 women with a mean age of 41.1 years (15-70 years). The mean follow-up period was 56 months (12-129 months), and the Spetzler-Martin grades were I (4 patients), II (9 patients), III (5 patients), and IV (4 patients). Residual AVMs were treated with stereotactic radiosurgery or surgery. The rate of complete obliteration with embolization alone was 27.3%. The overall obliteration rate after endovascular embolization with/without subsequent stereotactic radiosurgery or surgery was 72.7%. Eudragit-E caused two cases of cerebral infarction. One case of intracerebral hemorrhage due to postoperative hemodynamic changes also occurred. The rate of complications directly related to embolization was 10.0%. The safety and effectiveness of Eudragit-E embolization were satisfactory. PMID:25739432

  7. Endovascular retrieval of a prematurely deployed covered stent

    PubMed Central

    Miley, Jefferson T; Rodriguez, Gustavo J; Tummala, Ramachandra P

    2015-01-01

    Several techniques have been reported to address different endovascular device failures. We report the case of a premature deployment of a covered balloon mounted stent during endovascular repair of a post-traumatic carotid-cavernous fistula (CCF). A 50-year-old male suffered a fall resulting in loss of consciousness and multiple facial fractures. Five weeks later, he developed decreased left visual acuity, proptosis, chemosis, limited eye movements and cranial/orbit bruit. Cerebral angiography demonstrated a direct left CCF and endovascular repair with a 5.0 mm × 19 mm covered stent was planned. Once in the lacerum segment, increased resistance was encountered and the stent was withdrawn resulting in premature deployment. A 3 mm × 9 mm balloon was advanced over an exchange length microwire and through the stent lumen. Once distal to the stent, the balloon was inflated and slowly pulled back in contact with the stent. All devices were successfully withdrawn as a unit. The use of a balloon to retrieve a prematurely deployed balloon mounted stent is a potential rescue option if leaving the stent in situ carries risks. PMID:26120384

  8. Endovascular Treatment of Acute and Chronic Thoracic Aortic Injury

    SciTech Connect

    Raupach, Jan Ferko, Alexander; Lojik, Miroslav; Krajina, Antonin; Harrer, Jan; Dominik, Jan

    2007-11-15

    Our aim is to present midterm results after endovascular repair of acute and chronic blunt aortic injury. Between December 1999 and December 2005, 13 patients were endovascularly treated for blunt aortic injury. Ten patients, 8 men and 2 women, mean age 38.7 years, were treated for acute traumatic injury in the isthmus region of thoracic aorta. Stent-graftings were performed between the fifth hour and the sixth day after injury. Three patients (all males; mean age, 66 years; range, 59-71 years) were treated due to the presence of symptoms of chronic posttraumatic pseudoaneurysm of the thoracic aorta (mean time after injury, 29.4 years, range, 28-32). Fifteen stent-grafts were implanted in 13 patients. In the group with acute aortic injury one patient died due to failure of endovascular technique. Lower leg paraparesis appeared in one patient; the other eight patients were regularly followed up (1-72 months; mean, 35.6 months), without complications. In the group with posttraumatic pseudoaneurysms all three patients are alive. One patient suffered postoperatively from upper arm claudication, which was treated by carotidosubclavian bypass. We conclude that the endoluminal technique can be used successfully in the acute repair of aortic trauma and its consequences. Midterm results are satisfactory, with a low incidence of neurologic complications.

  9. Novel endovascular procedures and new developments in aortic surgery.

    PubMed

    Cheng, S W K

    2016-09-01

    Endovascular repair has evolved to become a viable mainstream treatment for aortic pathology in both acute and elective settings. As technology advanced, traditional anatomical barriers were progressively tackled using new devices and novel procedures, and there are now multiple options available to the vascular surgeon. In the abdominal aorta, advances in endovascular aneurysm repair have been in the treatment of hostile aortic necks using new sealing concepts and ancillary procedures, and in branch preservation using fenestrations and snorkels. Access challenges have been met with a percutaneous approach and low-profile devices, and standard protocols have improved mortality for ruptured aneurysms. In the thoracic aorta, more invasive hybrid procedures have given way gradually to branched endografts. Particular challenges to the anaesthetist include blood pressure control and the prevention of stroke and paraplegia. Current focus in the thoracic aorta is in treating aortic arch pathology and in optimal management of acute and chronic dissections. This review describes the latest trends in the endovascular treatment of aortic diseases and examines the current evidence for different modalities of management. PMID:27566806

  10. Contemporary Management of Type B Aortic Dissection in the Endovascular Era.

    PubMed

    Bannazadeh, Mohsen; Tadros, Rami O; McKinsey, James; Chander, Rajiv; Marin, Michael L; Faries, Peter L

    2016-04-01

    Aortic dissection (AD) is one of the most common catastrophic pathologies affecting the aorta. Anatomic classification is based on the origin of entry tear and its extension. Type A dissections originate in the ascending aorta, whereas the entry tear in Type B dissections starts distal to the left subclavian artery. The patients with aortic dissection who manifest complications such as rupture, malperfusion, aneurysmal degeneration, and intractable pain are classified as complicated AD. Risk factors for developing aortic dissection include age, male gender, and aortic wall structural abnormalities. The most common presenting symptom of acute aortic dissection is pain. Malperfusion occurs as a result of end-organ ischemia due to involvement of aortic branches from the dissecting process. This can happen in various locations causing mesenteric ischemia (mesenteric vessels), stroke (aortic arch vessels), renal failure (renal arteries), spinal ischemia, and limb ischemia (iliac or subclavian arteries). Aneurysmal degeneration is the most common complication of patients with chronic Type B dissection who are managed with medical therapy. Management of Type B aortic dissection (TBAD) remains controversial. Many groups recommend conservative therapy for newly diagnosed TBAD and reserve surgical management for patients who develop complications such as rupture, malperfusion, aneurysmal dilatation, and refractory pain. The mainstay of medical therapy includes antihypertensive medication to reduced ΔP/ ΔT by lowering blood pressure and heart rate. With the continued success of thoracic endovascular aortic repair (TEVAR), this procedure has been extended to treat TBAD in selected patients. The outcomes of TEVAR are promising, with early mortality rates from 10% to 20%. With promising results from these series, some groups recommend early TEVAR in uncomplicated TBAD to prevent future adverse events. The goals of endovascular treatment of TBAD are to cover the entry tear

  11. 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

  12. 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. PMID:25901660

  13. 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.

  14. Stroke Neurologist's Perspective on the New Endovascular Trials.

    PubMed

    Grotta, James C; Hacke, Werner

    2015-06-01

    Before December 2014, the only proven effective treatment for acute ischemic stroke was recombinant tissue-type plasminogen activator (r-tPA). This has now changed with the publication of the Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands (MR CLEAN), Endovascular Treatment for Small Core and Anterior Circulation Proximal Occlusion With Emphasis on Minimizing CT to Recanalization Times (ESCAPE), Extending the Time for Thrombolysis in Emergency Neurological Deficits--Intra-Arterial (EXTEND IA), Solitaire With the Intention for Thrombectomy as Primary Endovascular Treatment Trial (SWIFT PRIME), and Randomized Trial of Revascularization With the 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) studies. We review the main results of these studies and how they inform stroke patient management going forward. The main take home points for neurologists are (1) intra-arterial thrombectomy is a potently effective treatment and should be offered to patients who have documented occlusion in the distal internal carotid or the proximal middle cerebral artery, have a relatively normal noncontrast head computed tomographic scan, severe neurological deficit, and can have intra-arterial thrombectomy within 6 hours of last seen normal; (2) benefits are clear in patients receiving r-tPA before intra-arterial thrombectomy; r-tPA should not be withheld if the patient meets criteria, and benefit in patients who do not receive r-tPA or have r-tPA exclusions requires further study; and (3) these favorable results occur when intra-arterial thrombectomy is performed in an endovascular stroke center by a coordinated multidisciplinary team that extends from the prehospital stage to the endovascular suite, minimizes time to recanalization, uses stent-retriever devices, and avoids general

  15. Treatment of a Hepatic Artery Aneurysm by Endovascular Stent-Grafting

    SciTech Connect

    Jenssen, Guttorm L. Wirsching, Jan; Pedersen, Gustav; Amundsen, Svein Roar; Aune, Steinar; Dregelid, Einar; Jonung, Torbjorn; Daryapeyma, Alireza; Laxdal, Elin

    2007-06-15

    Aneurysms of the visceral arteries are rare. Traditional treatment has been surgical or endovascular with coil embolization. Recently, however, reports on endovascular therapy with stent-grafts have been published. We report the case of a 61-year-old man who was successfully treated with a stent-graft for a symptomatic combined celiac/hepatic artery aneurysm.

  16. Perspectives on endovascular training in traditional 5+2 vascular surgery fellowship training programs.

    PubMed

    Carruthers, Thomas N; Shahmohammadi, Kaveh; Farber, Alik; Rybin, Denis; Doros, Gheorghe; McPhee, James T; Kalish, Jeffrey E; Eslami, Mohammad H

    2016-04-01

    This study aimed to compare expectations and experiences of fellows to those of faculty in vascular surgery fellowship programs with regard to endovascular training. Anonymous surveys were sent to fellows (n = 235) and program directors (n = 147), with 79 fellows and 65 faculty members responding. Fellows noted higher expectations of their endovascular skills prior to starting fellowship than the faculty group reported expecting. Faculty assessed fellows' pre-training endovascular skills at a significantly lower level than the fellows' self-assessment. Fellows were significantly less satisfied with the structured aspects of endovascular training than the faculty believed them to be. Only 3% of fellows vs. 32% of faculty felt that the presence of an endovascular simulator affected how residents ranked fellowship programs during the match. In conclusion, incoming fellows in vascular surgery fellowship programs have high expectations of themselves, but may overestimate their actual pre-training endovascular skills. Fellows desire more structured endovascular training, which is not recognized by faculty. Endovascular simulators are valued, but may not be a significant draw in the match process. PMID:25972032

  17. Branched endovascular stent–graft for suprarenal aortic aneurysm: the future of aortic stent-grafting?

    PubMed Central

    Tse, Leonard W.; Steinmetz, Oren K.; Abraham, Cherrie Z.; Valenti, David A.; MacKenzie, Kent S.; Obrand, Daniel I.; Chuter, Timothy A.

    2004-01-01

    The use of a branched endovascular stent–graft to repair an aneurysm of the visceral aorta is described. The evolving role of branched endovascular stent–grafts in the management of aortic aneurysms is discussed, and the literature reviewed. PMID:15362327

  18. A Stabilized Finite Element Method for Modified Poisson-Nernst-Planck Equations to Determine Ion Flow Through a Nanopore

    PubMed Central

    Chaudhry, Jehanzeb Hameed; Comer, Jeffrey; Aksimentiev, Aleksei; Olson, Luke N.

    2013-01-01

    The conventional Poisson-Nernst-Planck equations do not account for the finite size of ions explicitly. This leads to solutions featuring unrealistically high ionic concentrations in the regions subject to external potentials, in particular, near highly charged surfaces. A modified form of the Poisson-Nernst-Planck equations accounts for steric effects and results in solutions with finite ion concentrations. Here, we evaluate numerical methods for solving the modified Poisson-Nernst-Planck equations by modeling electric field-driven transport of ions through a nanopore. We describe a novel, robust finite element solver that combines the applications of the Newton's method to the nonlinear Galerkin form of the equations, augmented with stabilization terms to appropriately handle the drift-diffusion processes. To make direct comparison with particle-based simulations possible, our method is specifically designed to produce solutions under periodic boundary conditions and to conserve the number of ions in the solution domain. We test our finite element solver on a set of challenging numerical experiments that include calculations of the ion distribution in a volume confined between two charged plates, calculations of the ionic current though a nanopore subject to an external electric field, and modeling the effect of a DNA molecule on the ion concentration and nanopore current. PMID:24363784

  19. Fast response vanes for sensing flow patterns in helicopter rotor environment. [wind tunnel tests of modified helicopter rotary wing

    NASA Technical Reports Server (NTRS)

    Barna, P. S.; Crossman, G. R.

    1974-01-01

    Wind tunnel experiments were conducted on four small-scale flow-direction vanes for the determination of aerodynamic response. The tests were further extended to include a standard sized low-inertia vane currently employed in aircraft flight testing. The four test vanes had different aspect ratios and were about 35 percent of the surface area of the standard vane. The test results indicate satisfactory damping and frequency response for all vanes tested and compare favorably with the standard design.

  20. Heavy metal adsorptivity of calcium-alginate-modified diethylenetriamine-silica gel and its application to a flow analytical system using flame atomic absorption spectrometry.

    PubMed

    Mori, Masanobu; Suzuki, Toshinobu; Sugita, Tsuyoshi; Nagai, Daisuke; Hirayama, Kazuo; Onozato, Makoto; Itabashi, Hideyuki

    2014-08-20

    This study aimed to evaluate the heavy metal adsorptivity of calcium-alginate-modified diethylenetriamine-silica gel (CaAD) and incorporate this biosorbent into a flow analytical system for heavy metal ions using flame atomic absorption spectrometry (FAAS). The biosorbent was synthesized by electrostatically coating calcium alginate onto diethylenetriamine (dien)-silica gel. Copper ion adsorption tests by a batch method showed that CaAD exhibited a higher adsorption rate compared with other biosorbents despite its low maximum adsorption capacity. Next, CaAD was packed into a 1mL microcolumn, which was connected to a flow analytical system equipped with an FAAS instrument. The flow system quantitatively adsorbed heavy metals and enriched their concentrations. This quantitative adsorption was achieved for pH 3-4 solutions containing 1.0×10(-6) M of heavy metal ions at a flow rate of 5.0 mL min(-1). Furthermore, the metal ions were successfully desorbed from CaAD at low nitric acid concentrations (0.05-0.15 M) than from the polyaminecarboxylic acid chelating resin (Chelex 100). Therefore, CaAD may be considered as a biosorbent that quickly adsorbs and easily desorbs analyte metal ions. In addition, the flow system enhanced the concentrations of heavy metals such as Cu(2+), Zn(2+), and Pb(2+) by 50-fold. This new enrichment system successfully performed the separation and determination of Cu(2+) (5.0×10(-8)M) and Zn(2+) (5.7×10(-8) M) in a river water sample and Pb(2+) (3.8×10(-9) M) in a ground water sample. PMID:25086892

  1. PbO2-modified graphite felt as the positive electrode for an all-vanadium redox flow battery

    NASA Astrophysics Data System (ADS)

    Wu, Xiaoxin; Xu, Hongfeng; Lu, Lu; Zhao, Hong; Fu, Jie; Shen, Yang; Xu, Pengcheng; Dong, Yiming

    2014-03-01

    A novel approach for enhancing the electrochemical performance of graphite felt electrodes by employing non-precious metal oxides is designed for an all-vanadium redox flow battery (VRFB). Lead dioxide (PbO2) is prepared through pulse electrodeposition method and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The electrochemical performance of the prepared electrode is evaluated through cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Results show that PbO2 exhibits excellent electro-catalytic activity and reactive velocity to vanadium redox couples. The coulombic efficiency (CE), voltage efficiency (VE), and energy efficiency (EE) of the vanadium redox flow battery with as-prepared electrodes at 70 mA cm-2 are 99.5%, 82.4%, and 82.0%, respectively; these values are much higher than those of a cell assembled with bare graphite felt electrodes. The outstanding electro-catalytic activity and mechanical stability of PbO2 are advantageous in facilitating the redox reaction of vanadium ions, leading to the efficient operation of a vanadium redox flow battery.

  2. Long-Term Follow-Up After Endovascular Treatment of Acute Aortic Emergencies

    SciTech Connect

    Pitton, M. B. Herber, S.; Schmiedt, W.; Neufang, A.; Dorweiler, B.; Dueber, C.

    2008-01-15

    demonstrated a satisfactory follow-up despite the necessity for reintervention and graft extension in 3 of 6 cases (50%). Two patients with type B dissection died due to mesenteric ischemia despite sufficient mesenteric blood flow being restored (but too late). Two suffered from neurologic complications, 1 from paraplegia and 1 from cerebral ischemia (probably embolic), 1 from penetrating ulcer, and 1 from persistent ischemia of the kidney. Five of 9 (56%) patients with symptomatic thoracic aneurysm demonstrated endoleaks during follow-up and there was an increase in the aneurysm in 1. Conclusion. Endovascular treatment is safe and effective for emergency treatment of life-threatening acute thoracic aortic syndromes. Results are encouraging, particularly for traumatic aortic ruptures. However, regular follow-up is mandatory, particularly in the other pathologies, to identify late complications of the stent-graft and to perform appropriate additional corrections as required.

  3. Comparison of two stents in modifying cerebral aneurysm hemodynamics.

    PubMed

    Kim, Minsuok; Taulbee, Dale B; Tremmel, Markus; Meng, Hui

    2008-05-01

    There is a general lack of quantitative understanding about how specific design features of endovascular stents (struts and mesh design, porosity) affect the hemodynamics in intracranial aneurysms. To shed light on this issue, we studied two commercial high-porosity stents (Tristar stent and Wallstent) in aneurysm models of varying vessel curvature as well as in a patient-specific model using Computational Fluid Dynamics. We investigated how these stents modify hemodynamic parameters such as aneurysmal inflow rate, stasis, and wall shear stress, and how such changes are related to the specific designs. We found that the flow damping effect of stents and resulting aneurysmal stasis and wall shear stress are strongly influenced by stent porosity, strut design, and mesh hole shape. We also confirmed that the damping effect is significantly reduced at higher vessel curvatures, which indicates limited usefulness of high-porosity stents as a stand-alone treatment. Finally, we showed that the stasis-inducing performance of stents in 3D geometries can be predicted from the hydraulic resistance of their flat mesh screens. From this, we propose a methodology to cost-effectively compare different stent designs before running a full 3D simulation. PMID:18264766

  4. Comparison of Two Stents in Modifying Cerebral Aneurysm Hemodynamics

    PubMed Central

    Kim, Minsuok; Taulbee, Dale B.; Tremmel, Markus; Meng, Hui

    2009-01-01

    There is a general lack of quantitative understanding about how specific design features of endovascular stents (struts and mesh design, porosity) affect the hemodynamics in intracranial aneurysms. To shed light on this issue, we studied two commercial high-porosity stents (Tristar stent™ and Wallstent®) in aneurysm models of varying vessel curvature as well as in a patient-specific model using Computational Fluid Dynamics. We investigated how these stents modify hemodynamic parameters such as aneurysmal inflow rate, stasis, and wall shear stress, and how such changes are related to the specific designs. We found that the flow damping effect of stents and resulting aneurysmal stasis and wall shear stress are strongly influenced by stent porosity, strut design, and mesh hole shape. We also confirmed that the damping effect is significantly reduced at higher vessel curvatures, which indicates limited usefulness of high-porosity stents as a stand-alone treatment. Finally, we showed that the stasis-inducing performance of stents in 3D geometries can be predicted from the hydraulic resistance of their flat mesh screens. From this, we propose a methodology to cost-effectively compare different stent designs before running a full 3D simulation. PMID:18264766

  5. The modified FACS calcein AM retention assay: A high throughput flow cytometer based method to measure cytotoxicity.

    PubMed

    Gillissen, M A; Yasuda, E; de Jong, G; Levie, S E; Go, D; Spits, H; van Helden, P M; Hazenberg, M D

    2016-07-01

    Current methods to determine cellular cytotoxicity in vitro are hampered by background signals that are caused by auto-fluorescent target and effector cells and by non-specific cell death. We combined and adjusted existing cell viability assays to develop a method that allows for highly reproducible, accurate, single cell analysis by high throughput FACS, in which non-specific cell death is corrected for. In this assay the number of living, calcein AM labeled cells that are green fluorescent are quantified by adding a fixed number of unlabeled calibration beads to the analysis. Using this modified FACS calcein AM retention method, we found EC50 values to be highly reproducible and considerably lower compared to EC50 values obtained by conventional assays, displaying the high sensitivity of this assay. PMID:27084117

  6. Predictor's analysis of anterior circulation cerebral infarction after the endovascular treatment of anterior communicating artery aneurysms

    PubMed Central

    Sun, Liqian; Jing, Xiaobin; Cui, Changmeng; Cui, Jianzhong

    2014-01-01

    Background: Despite increasing acceptance of endovascular coiling for treating anterior communicating artery (ACoA) aneurysms, anterior circulation cerebral infarction (ACI) after embolization remains a limitation. With higher incidence, higher morbidity and higher mortality, it is one of the main factors influencing the ACoA aneurysms prognosis. Determining the risk factors leading to ACI after embolization will have clinical significance. Through retrospective case analysis, this study investigated the risk factors related to ACI after embolization in order to provide information to serve the clinical practice. Materials and Methods: A retrospective review was performed of patients who had undergone coiling of ACoA aneurysms from 2008 to 2012. All patients had ruptured prior to the completion of embolization. Cases with acute stroke symptoms without alternative diagnoses after embolization were diagnosed as ACI. A total of 32 risk factors such as age, sex, hypertension, diabetes mellitus, modified Fisher grade, Hunt-Hess grade, ventricular hemorrhage, etc. were analyzed using univariate and logistic regression analysis. Results: Univariate analysis showed that negative fluid volume balance (P = 0.041 <0.05) and modified Fisher grade (P = 0.049 <0.05) reached statistical significance, suggesting that they might be risk factors for ACI after embolization. Multiple logistic regression analysis showed that modified Fisher grade was significantly associated with ACI after embolization, suggesting that it was an independent risk factor (odds ratios (OR): 4.968, 95% confidence intervals (CI): 1.013-24.360, P = 0.048). Conclusion: Modified Fisher grade is an independent risk factor for ACI after embolization. PMID:25097601

  7. Fenestrated endovascular repair of abdominal aortic aneurysms: a less invasive option for the treatment of juxtarenal aortic aneurysms.

    PubMed

    Ehlert, Bryan A; Abularrage, Christopher J

    2016-05-01

    Endovascular aortic aneurysm repair has become the predominant surgical therapy for abdominal aortic aneurysms. Whereas anatomical limitations had become the major contraindication to endovascular treatment, fenestrated stent grafts were developed to overcome such obstacles. Fenestrated endovascular aortic aneurysm repair now provides an additional treatment option for patients felt to be unsuitable for an invasive open repair whose anatomy is not compatible with more traditional stent grafts. We review the evolution of fenestrated endovascular aortic aneurysm repair and compare its safety and efficacy to other endovascular options. PMID:27092859

  8. Endovascular Stenting under Cardiac and Cerebral Protection for Subclavian Steal after Coronary Artery Bypass Grafting Due to Right Subclavian Artery Origin Stenosis.

    PubMed

    Sakamoto, Shigeyuki; Kiura, Yoshihiro; Okazaki, Takahito; Ichinose, Nobuhiko; Kurisu, Kaoru

    2015-03-01

    Coronary-subclavian steal (CSS) can occur after coronary artery bypass grafting (CABG) using the internal thoracic artery (ITA). Subclavian artery (SA) stenosis proximal to the ITA graft causes CSS. We describe a technique for cardiac and cerebral protection during endovascular stenting for CSS due to right SA origin stenosis after CABG. A 64-year-old man with a history of CABG using the right ITA presented with exertional right arm claudication. Angiogram showed a CSS and retrograde blood flow in the right vertebral artery (VA) due to severe stenosis of the right SA origin. Endovascular treatment of the right SA stenosis was planned. For cardiac and cerebral protection, distal balloon protection by inflating a 5.2-F occlusion balloon catheter in the SA proximal to the origin of the right VA and ITA through the right brachial artery approach and distal filter protection of the right internal carotid artery (ICA) through the left femoral artery (FA) approach were performed. Endovascular stenting for SA stenosis from the right FA approach was performed under cardiac and cerebral protection by filter-protection of the ICA and balloon-protection of the VA and ITA. Successful treatment of SA severe stenosis was achieved with no complications. PMID:25874182

  9. Endovascular Stenting under Cardiac and Cerebral Protection for Subclavian Steal after Coronary Artery Bypass Grafting Due to Right Subclavian Artery Origin Stenosis

    PubMed Central

    Kiura, Yoshihiro; Okazaki, Takahito; Ichinose, Nobuhiko; Kurisu, Kaoru

    2015-01-01

    Coronary-subclavian steal (CSS) can occur after coronary artery bypass grafting (CABG) using the internal thoracic artery (ITA). Subclavian artery (SA) stenosis proximal to the ITA graft causes CSS. We describe a technique for cardiac and cerebral protection during endovascular stenting for CSS due to right SA origin stenosis after CABG. A 64-year-old man with a history of CABG using the right ITA presented with exertional right arm claudication. Angiogram showed a CSS and retrograde blood flow in the right vertebral artery (VA) due to severe stenosis of the right SA origin. Endovascular treatment of the right SA stenosis was planned. For cardiac and cerebral protection, distal balloon protection by inflating a 5.2-F occlusion balloon catheter in the SA proximal to the origin of the right VA and ITA through the right brachial artery approach and distal filter protection of the right internal carotid artery (ICA) through the left femoral artery (FA) approach were performed. Endovascular stenting for SA stenosis from the right FA approach was performed under cardiac and cerebral protection by filter-protection of the ICA and balloon-protection of the VA and ITA. Successful treatment of SA severe stenosis was achieved with no complications. PMID:25874182

  10. Mechanical behavior of pathological and normal red blood cells in microvascular flow based on modified level-set method

    NASA Astrophysics Data System (ADS)

    Zhang, XiWen; Ma, FangChao; Hao, PengFei; Yao, ZhaoHui

    2016-01-01

    The research of the motion and deformation of the RBCs is important to reveal the mechanism of blood diseases. A numerical method has been developed with level set formulation for elastic membrane immersed in incompressible fluid. The numerical model satisfies mass and energy conservation without the leaking problems in classical Immersed Boundary Method (IBM), at the same time, computing grid we used can be much smaller than the general literatures. The motion and deformation of a red blood cell (including pathological & normal status) in microvascular flow are simulated. It is found that the Reynolds number and membrane's stiffness play an important role in the transmutation and oscillation of the elastic membrane. The normal biconcave shape of the RBC is propitious to create high deformation than other pathological shapes. With reduced viscosity of the interior fluid both the velocity of the blood and the deformability of the cell reduced. With increased viscosity of the plasma both the velocity of the blood and the deformability of the cell reduced. The tank treading of the RBC membrane is observed at low enough viscosity contrast in shear flow. The tank tread fixed inclination angle of the cell depends on the shear ratio and viscosity contrast, which can be compared with the experimental observation well.

  11. Endovascular Internal Trapping of Ruptured Occipital Artery Pseudoaneurysm Associated with Occipital-Internal Jugular Vein Fistula in Neurofibromatosis Type 1.

    PubMed

    Imahori, Taichiro; Fujita, Atsushi; Hosoda, Kohkichi; Kohmura, Eiji

    2016-05-01

    Spontaneous cervical extradural pseudoaneurysms or arteriovenous fistulas (AVFs) are rare vascular diseases. We report a case of ruptured occipital artery (OA) pseudoaneurysm associated with occipital-internal jugular vein (IJV) fistula in neurofibromatosis type 1. Endovascular internal trapping via the OA was attempted; however, the distal entry of the OA could not be accessed because of the high shunt flow and tortuosity of the OA. The distal part of the OA was obliterated with coil via a transvenous approach through the IJV and pseudoaneurysm. The proximal entry of the OA was obliterated with coil and glue under proximal flow control with a balloon, and the fistula was successfully obliterated without placement of coils in the pseudoaneurysm. When ordinary internal trapping via a transarterial approach is not possible, the transvenous approach should be considered as an alternative for AVF associated with an aneurysmal component. PMID:26971039

  12. Endovascular Repair of a Type III Thoracoabdominal Aortic Aneurysm in a Patient with Occlusion of Visceral Arteries

    SciTech Connect

    Klonaris, Chris Katsargyris, Athanasios; Giannopoulos, Athanasios; Georgopoulos, Sotiris; Tsigris, Chris; Michail, Othon; Marinos, George; Bastounis, Elias

    2007-07-15

    The successful endovascular repair of a type III thoracoabdominal aortic aneurysm (TAAA) with the use of a tube endograft is reported. A 56-year-old male with a 6.4-cm type III TAAA, a 4.2-cm infrarenal abdominal aortic aneurysm, and chronic renal insufficiency presented with flank pain, nausea, acute anuria, and serum creatinine of 6.1 mg/dl. Acute occlusion of the left solitary renal artery was diagnosed and emergent recanalization with percutaneus transluminal angioplasty and stenting was performed successfully, with reversal of the serum creatinine level at 1.6 mg/dl. Further imaging studies for TAAA management revealed ostial occlusion of both the celiac artery (CA) and the superior mesenteric artery (SMA) but a hypertrophic inferior mesenteric artery (IMA) providing retrograde flow to the aforementioned vessels. This rare anatomic serendipity allowed us to repair the TAAA simply by using a two-component tube endograft without fenestrations (Zenith; William Cook, Bjaeverskov, Denmark) that covered the entire length of the aneurysm, including the CA and SMA origins, since a natural arterial bypass from the IMA to the CA and SMA already existed, affording protection from gastrointestinal ischemic complications. The patient had a fast and uneventful recovery and is currently doing well 6 months after the procedure. To our knowledge, this is the first report in the English literature of successful endovascular repair of a TAAA involving visceral arteries with the simple use of a tube endograft.

  13. A new option for endovascular treatment of leg ulcers caused by venous insufficiency with fluoroscopically guided sclerotherapy

    PubMed Central

    Garcarek, Jerzy; Falkowski, Aleksander; Rybak, Zbigniew; Jargiello, Tomasz; Łokaj, Marek; Czapla, Norbert

    2015-01-01

    Introduction Ulcers of lower legs are the most bothersome complication of chronic venous insufficiency (CVI). Aim To assess the effectiveness of endovascular fluoroscopically guided sclerotherapy for the treatment of venous ulcers. Material and methods Thirty-eight limbs in 35 patients with crural venous ulcers were treated with guided sclerotherapy under the control of fluoroscopy. Patients with non-healing ulcers in the course of chronic venous insufficiency, with and without features of past deep vein thrombosis, were qualified for the study. Doppler ultrasound and dynamic venography with mapping of venous flow were performed. Ambulatory venous pressure measurements, leg circumference and varicography were performed just before and following the procedure. Results In 84% of cases, ulcers were treated successfully and healed. Patients with post-thrombotic syndrome (n = 17) healed in 13 (76.5%) cases, whereas patients without post-thrombotic syndrome (n = 21) healed in 19 (90.5%) cases. The mean time of healing of an ulcer for all patients was 83 days (in the first group it was 121 days and in the second group 67 days). Recurrence of an ulcer was observed in 10 limbs: 6 cases in the first group and 4 cases in the second group. Occurrence of deep vein thrombosis associated with the procedure was not observed. Temporary complications were reported but none giving a serious clinical outcome. Conclusions Endovascular fluoroscopically guided sclerotherapy can be an alternative method of treatment of venous ulcers, especially in situations when surgical procedures or other options of treatment are impossible. PMID:26649090

  14. Endovascular Treatment of Ruptured Abdominal Aneurysm into the Inferior Vena Cava in Patient After Stent Graft Placement

    SciTech Connect

    Juszkat, Robert; Pukacki, Fryderyk; Zarzecka, Anna; Kulesza, Jerzy; Majewski, Waclaw

    2009-07-15

    We report the case of a patient who underwent endovascular repair and then reintervention as a result of the presence of a persistent endoleak complicated by an aortocaval fistula. A 76-year-old patient with a history of endovascular treatment for abdominal aortic aneurysm 2 years earlier had a palpable abdominal mass, high-output cardiac failure, and renal failure. A computed tomographic scan and angiography revealed bending of the right iliac limb, a type I endoleak, and rupture of the aneurysm into the inferior vena cava with aortocaval fistula formation. An iliac extension was positioned in the right external iliac artery. The procedure was finished successfully. Control angiography showed normal flow within the endoprosthesis, and both iliac arteries were without signs of endoleakage and aortocaval fistula. Ectatic common iliac artery may lead to a late distal attachment site endoleak. The application of a stent graft in cases of secondary aortocaval fistula after stent graft repair is a good option, particularly in emergency cases.

  15. Influence of exchange group of modified glycidyl methacrylate polymer on phenol removal: A study by batch and continuous flow processes.

    PubMed

    Aversa, Thiago Muza; da Silva, Carla Michele Frota; da Rocha, Paulo Cristiano Silva; Lucas, Elizabete Fernandes

    2016-11-01

    Contamination of water by phenol is potentially a serious problem due to its high toxicity and its acid character. In this way some treatment process to remove or reduce the phenol concentration before contaminated water disposal on the environment is required. Currently, phenol can be removed by charcoal adsorption, but this process does not allow easy regeneration of the adsorbent. In contrast, polymeric resins are easily regenerated and can be reused in others cycles of adsorption process. In this work, the interaction of phenol with two polymeric resins was investigated, one of them containing a weakly basic anionic exchange group (GD-DEA) and the other, a strongly basic group (GD-QUAT). Both ion exchange resins were obtained through chemical modifications from a base porous resin composed of glycidyl methacrylate (GMA) and divinyl benzene (DVB). Evaluation tests with resins were carried out with 30 mg/L of phenol in water solution, at pH 6 and 10, employing two distinct processes: (i) batch, to evaluate the effect of temperature, and (ii) continuous flow, to assess the breakthrough of the resins. Batch tests revealed that the systems did not follow the model proposed by Langmuir due to the negative values obtained for the constant b and for the maximum adsorption capacity, Q0. However, satisfactory results for the constants KF and n allowed assuming that the behavior of systems followed the Freundlich model, leading to the conclusion that resin GD-DEA had the best interaction with the phenol when in a solution having pH 10 (phenoxide ions). The continuous flow tests corroborated this conclusion since the performance of GD-DEA in removing phenol was also best at pH 10, indicating that the greater availability of the electron pair in the resin with the weakly basic donor group contributed to enhance the resin's interaction with the phenoxide ions. PMID:27494606

  16. Endograft Collapse After Endovascular Treatment for Thoracic Aortic Disease

    SciTech Connect

    Bandorski, Dirk Brueck, Martin; Guenther, Hans-Ulrich; Manke, Christoph

    2010-06-15

    Endovascular treatment is an established therapy for thoracic aortic disease. Collapse of the endograft is a potentially fatal complication. We reviewed 16 patients with a thoracic endograft between 2001 and 2006. Medical records of the treated patients were studied. Data collected include age, gender, diagnosis, indication for endoluminal treatment, type of endograft, and time of follow up. All patients (n = 16; mean age, 61 years; range, 21-82 years) underwent computed tomography (CT) for location of the lesion and planning of the intervention. Time of follow-up with CT scan ranged from 1 to 61 months. Indications for endovascular treatment were degenerative aneurysm (n = 7; 44%), aortic dissection (n = 2; 12%), perforated aortic ulcer (n = 4; 25%), and traumatic aortic injury (n = 3; 19%). Three patients suffered from a collapse of the endograft (one patient distal, two patients proximal) between 3 and 8 days after endovascular treatment. These patients were younger (mean age, 37 {+-} 25 years vs. 67 {+-} 16 years; P < 0.05) and showed more oversizing (proximal, 36 {+-} 19.8% vs. 29 {+-} 20.7% [P > 0.05]; distal, 45 {+-} 23.5% vs. 38 {+-} 21.7% [P > 0.05]). Proximal collapse was corrected by placing a bare stent. In conclusion, risk factors for stent-graft collapse are a small lumen of the aorta and a small radius of the aortic arch curvature (young patients), as well as oversizing, which is an important risk factor and is described for different types of endografts and protheses (Gore TAG and Cook Zenith). Dilatation of the collapsed stent-graft is not sufficient. Following therapy implantation of a second stent or surgery is necessary in patients with a proximal endograft collapse. Distal endograft collapse can possibly be treated conservatively under close follow-up.

  17. Endovascular Treatment of Femoropopliteal Aneurysms: A Five-Year Experience

    SciTech Connect

    Lagana, Domenico Carrafiello, Gianpaolo; Mangini, Monica; Caronno, Roberto; Giorgianni, Andrea; Lumia, Domenico; Castelli, Patrizio; Fugazzola, Carlo

    2006-10-15

    Purpose. To assess the effectiveness of endovascular treatment of femoropopliteal aneurysms (FPAs). Methods. In the last 5 years, we have treated 17 FPAs (diameter 21-75 cm, mean 38.4 cm; length 27-100 cm, mean 72.5 cm) in 15 patients (age 57-80 years, mean 70.9 years). The diagnosis was obtained by color Doppler ultrasound (CDU) and the procedure was planned by CT angiography (CTA) and preprocedural angiography. Eight FPAs were excluded with only one stent-graft; in 8 patients, two stent-grafts were positioned; and in 1 patient, three stent-grafts were used. In 14 cases we used a Wallgraft endoprosthesis, in 2 cases a Hemobahn, and in 1 case an Excluder contralateral leg. The patients were followed up with CDU and occasionally with CTA. Results. Immediate technical success was obtained in 17 of 17 cases (100%). One patient died during the first year. During a mean follow-up of 26.9 months (range 3-60 months) we observed 6 of 16 (38%) stent-graft occlusions (3 of which were recanalized with locoregional thrombolysis and 3 with mechanical thrombectomy). Two stent-grafts were patent at 12 and 24 months. Four patients experienced subsequent occlusions and recanalizations until corrected by surgical bypass (1 at 14 months, 2 at 18 months, and 1 at 36 months). Therefore the primary patency was 63% and assisted patency was 73%. Conclusion. The endovascular approach is a minimally invasive treatment option for FPAs. Moreover endovascular stent-grafting does not necessarily preclude conventional surgical repair, but it can delay it. Longer follow-up will be needed to determine the long-term patency rate.

  18. Endovascular Treatment of Epistaxis: Indications, Management, and Outcome

    SciTech Connect

    Strach, Katharina; Schroeck, Andreas; Wilhelm, Kai; Greschus, Susanne; Tschampa, Henriette; Moehlenbruch, Markus; Naehle, Claas P.; Jakob, Mark; Gerstner, Andreas O. H.; Bootz, Friedrich; Schild, Hans H.; Urbach, Horst

    2011-12-15

    Objective: Epistaxis is a common clinical problem, and the majority of bleedings can be managed conservatively. However, due to extensive and sometimes life-threatening bleeding, further treatment, such as superselective embolization, may be required. We report our experience with endovascular treatment of life-threatening epistaxis. Methods: All patients presenting with excessive epistaxis, which received endovascular treatment at a German tertiary care facility between January 2001 and December 2009, were retrospectively identified. Demographic data, etiology, origin and clinical relevance of bleeding, interventional approach, therapy-associated complications, and outcome were assessed. Results: A total of 48 patients required 53 embolizations. Depending on the etiology of bleeding, patients were assigned to three groups: 1) idiopathic epistaxis (31/48), 2) traumatic or iatrogenic epistaxis (12/48), and 3) hereditary hemorrhagic telangiectasia (HHT) (5/48). Eleven of 48 patients required blood transfusions, and 9 of these 11 patients (82%) were termed clinically unstable. The sphenopalatine artery was embolized unilaterally in 10 of 53 (18.9%) and bilaterally in 41 of 53 (77.4%) procedures. During the same procedure, additional vessels were embolized in three patients (3/53; 5.7%). In 2 of 53(3.8%) cases, the internal carotid artery (ICA) was occluded. Long-term success rates of embolization were 29 of 31 (93.5%) for group 1 and 11 of 12 (91.7%) for group 2 patients. Embolization of patients with HHT offered at least a temporary relief in three of five (60%) cases. Two major complications (necrosis of nasal tip and transient hemiparesis) occurred after embolization. Conclusions: Endovascular treatment proves to be effective for prolonged and life-threatening epistaxis. It is easily repeatable if the first procedure is not successful and offers a good risk-benefit profile.

  19. Amperometric determination of bonded glucose with an MnO(2) and glucose oxidase bulk-modified screen-printed electrode using flow-injection analysis.

    PubMed

    Turkusic, Emir; Kalcher, Josef; Kahrovic, Emira; Beyene, Negussie W; Moderegger, Helmut; Sofic, Emin; Begic, Sabina; Kalcher, Kurt

    2005-01-30

    A screen-printed amperometric biosensor based on carbon ink double bulk-modified with MnO(2) as a mediator and glucose oxidase as a biocomponent was investigated for its ability to serve as a detector for bonded glucose in different compounds, such as cellobiose, saccharose, (-)-4-nitrophenyl-beta-d-glucopyranoside, as well as in beer samples by flow-injection analysis (FIA). The biosensor could be operated under physiological conditions (0.1M phosphate buffer, pH 7.5) and exhibited good reproducibility and stability. Bonded glucose was released with glucosidase in solution, and the free glucose was detected with the modified screen-printed electrode (SPE). The release of glucose by the aid of glucosidase from cellobiose, saccharose and (-)-4-nitrophenyl-beta-d-glucopyranoside in solution showed that stoichiometric quantities of free glucose could be monitored in all three cases. The linear range of the amperometric response of the biosensor in the FIA-mode flow rate 0.2mLmin(-1), injection volume 0.25mL, operation potential 0.48V versus Ag/AgCl) extends from 11 to 13,900mumolL(-1) glucose in free form. The limit of detection (3sigma) is 1mumolL(-1) glucose. A concentration of 100mumolL(-1) yields a relative standard deviation of approximately 7% with five injections. These values correspond to the same concentrations of bonded glucose supposed that it is liberated quantitatively (incubation for 2h with glucosidase). Bonded glucose could be determined in beer samples using the same assay. The results corresponded very well with the reference procedure. PMID:18969835

  20. Endovascular therapy for tracheoinnominate artery fistula: a temporizing measure.

    PubMed

    Wall, L Philipp; Gasparis, Antonios; Criado, Enrique

    2005-01-01

    Tracheoinnominate artery fistula remains an uncommon, highly fatal complication of tracheostomy and peritracheal pathology. Endovascular placement of a covered stent can provide control of the fistula. Depending on the conditions of the trachea and peritracheal tissues, the fistula may heal or the stent may become infected and/or further erode into the trachea. We report on a case of a patient with a tracheoinnominate artery fistula related to peritracheal tumor invasion, radiation therapy, and tracheostomy. The fistula was initially excluded with a covered stent, but a few weeks later hemoptysis recurred secondary to deep tracheal erosion by the covered stent. PMID:15714376

  1. Endovascular repair of tracheo-innominate artery fistula.

    PubMed

    Wang, Po-Kai; Yen, Pao-Sheng; Shyr, Ming-Hwang; Chen, Tsung-Ying; Chen, Albert; Liu, Hsu-Tang

    2009-03-01

    Innominate arterial wall rupture with pseudoaneurysm formation was found during angiography in a 39-year-old woman 2 days after she had undergone percutaneous dilatational tracheostomy. Endovascular stent surgery and balloon angioplasty were performed but these procedures failed to control the massive bleeding resulting from an endoleak. We report the clinical presentations and describe the treatment of a tracheo-innominate artery fistula in our patient. We also reviewed the algorithms of management and the rescue options for treating a tracheo-innominate artery fistula. PMID:19318299

  2. Aortoesophageal fistula after thoracic endovascular aortic repair and transthoracic embolization.

    PubMed

    Riesenman, Paul J; Farber, Mark A; Mauro, Matthew A; Selzman, Craig H; Feins, Richard H

    2007-10-01

    Endografts are more commonly being used to treat thoracic aortic aneurysms and other vascular lesions. Endoleaks are a potential complication of this treatment modality and can be associated with aneurysmal sac expansion and rupture. This case report presents a patient who developed a type IA endoleak after endograft repair of a descending thoracic aneurysm. The endoleak was successfully treated through computed tomographic-guided transthoracic embolization, although the patient experienced lower extremity paraparesis postprocedurally. The patient's endovascular repair was complicated by the development of an aortoesophageal fistula and endograft infection necessitating operative débridement and endograft explantation. PMID:17903656

  3. De novo periaortic fibrosis after endovascular aortic repair.

    PubMed

    Alomran, Faris; de Blic, Romain; Mallios, Alexandros; Costanzo, Alessandro; Boura, Benoit; Combes, Myriam

    2014-02-01

    We report a case of a 63-year-old man presenting with abdominal pain and hydronephrosis secondary to periaortic fibrosis (PAF) 8 months after an endovascular aortic repair (EVAR) using a woven polyester bifurcated graft. De novo delayed PAF after open repair is rare and even more infrequent after EVAR. All 3 previously reported cases occurred after woven polyester grafts and no reported cases after polytetrafluorethylene grafts. Management included steroidal anti-inflammatory treatment and bilateral double J tube placement. Satisfactory results were obtained. PMID:24275428

  4. Endovascular vs. Open Repair for Ruptured Abdominal Aortic Aneurysm

    PubMed Central

    Patelis, Nikolaos; Moris, Demetrios; Karaolanis, Georgios; Georgopoulos, Sotiris

    2016-01-01

    Background Patients presenting with ruptured abdominal aortic aneurysms are most often treated with open repair despite the fact that endovascular aneurysm repair is a less invasive and widely accepted method with clear benefits for elective aortic aneurysm patients. A debate exists regarding the definitive benefit in endovascular repair for patients with a ruptured abdominal aortic aneurysm. The aim of this literature review was to determine if any trends exist in favor of either open or endovascular repair. Material/Methods A literature search was performed using PUBMED, OVID, and Google Scholar databases. The search yielded 64 publications. Results Out of 64 publications, 25 were retrospective studies, 12 were population-based, 21 were prospective, 5 were the results of RCTs, and 1 was a case-series. Sixty-one studies reported on early mortality and provided data comparing endovascular repair (rEVAR) and open repair (rOR) for ruptured abdominal aneurysm groups. Twenty-nine of these studies reported that rEVAR has a lower early mortality rate. Late mortality after rEVAR compared to that of rOR was reported in 21 studies for a period of 3 to 60 months. Results of 61.9% of the studies found no difference in late mortality rates between these 2 groups. Thirty-nine publications reported on the incidence of complications. Approximately half of these publications support that the rEVAR group has a lower complication rate and the other half found no difference between the groups. Length of hospital stay has been reported to be shorter for rEVAR in most studies. Blood loss and need for transfusion of either red cells or fresh frozen plasma was consistently lower in the rEVAR group. Conclusions Differences between the included publications affect the outcomes. Randomized control trials have not been able to provide clear conclusions. rEVAR can now be considered a safe method of treating rAAA, and is at least equal to the well-established rOR method. PMID:27090791

  5. Endovascular coil embolization of unruptured posterior communicating artery aneurysm.

    PubMed

    Binning, Mandy; Hakma, Zakaria; Veznedaroglu, Erol

    2014-07-01

    The patient is a 60-year-old woman who presented to her primary care physician with new onset of headache. She was neurologically intact without cranial nerve deficit. An outpatient CT angiogram (CTA) revealed no subarachnoid hemorrhage, but showed a right-sided posterior communicating artery aneurysm measuring 11 mm by 10 mm. Digitally subtracted cerebral angiography confirmed these measurements and showed that the aneurysm was amenable to endovascular coil embolization. The patient underwent aneurysm coiling without complication and was discharged to home on postoperative Day 1. The video can be found here: http://youtu.be/MjOc3Zpv2K8 . PMID:24983726

  6. Celiac Injury Due to Arcuate Ligament: An Endovascular Approach

    SciTech Connect

    Zini, Chiara Corona, Mario Boatta, Emanuele Wlderk, Andrea Salvatori, Filippo Maria Fanelli, Fabrizio

    2013-06-15

    Celiac trunk injures are rare events, with high mortality rates and difficult management. Endovascular treatment may be considered to avoid bleeding. We report a case of severe bleeding in a 37-year-old man resulting from celiac trunk stretching after a motorcycle crash. Because direct celiac trunk catheterization was not possible, a retrograde catheterization of the common hepatic artery was performed via the superior mesenteric artery. Two vascular plugs (type IV) were released, and the exclusion of the celiac trunk origin was completed with the deployment of an aortic cuff. The patient's clinical condition immediately improved, and after 6 months' follow-up, imaging confirmed the complete exclusion of the celiac trunk.

  7. Virtual reality simulation for the optimization of endovascular procedures: current perspectives.

    PubMed

    Rudarakanchana, Nung; Van Herzeele, Isabelle; Desender, Liesbeth; Cheshire, Nicholas J W

    2015-01-01

    Endovascular technologies are rapidly evolving, often requiring coordination and cooperation between clinicians and technicians from diverse specialties. These multidisciplinary interactions lead to challenges that are reflected in the high rate of errors occurring during endovascular procedures. Endovascular virtual reality (VR) simulation has evolved from simple benchtop devices to full physic simulators with advanced haptics and dynamic imaging and physiological controls. The latest developments in this field include the use of fully immersive simulated hybrid angiosuites to train whole endovascular teams in crisis resource management and novel technologies that enable practitioners to build VR simulations based on patient-specific anatomy. As our understanding of the skills, both technical and nontechnical, required for optimal endovascular performance improves, the requisite tools for objective assessment of these skills are being developed and will further enable the use of VR simulation in the training and assessment of endovascular interventionalists and their entire teams. Simulation training that allows deliberate practice without danger to patients may be key to bridging the gap between new endovascular technology and improved patient outcomes. PMID:25792841

  8. Virtual reality simulation for the optimization of endovascular procedures: current perspectives

    PubMed Central

    Rudarakanchana, Nung; Van Herzeele, Isabelle; Desender, Liesbeth; Cheshire, Nicholas JW

    2015-01-01

    Endovascular technologies are rapidly evolving, often requiring coordination and cooperation between clinicians and technicians from diverse specialties. These multidisciplinary interactions lead to challenges that are reflected in the high rate of errors occurring during endovascular procedures. Endovascular virtual reality (VR) simulation has evolved from simple benchtop devices to full physic simulators with advanced haptics and dynamic imaging and physiological controls. The latest developments in this field include the use of fully immersive simulated hybrid angiosuites to train whole endovascular teams in crisis resource management and novel technologies that enable practitioners to build VR simulations based on patient-specific anatomy. As our understanding of the skills, both technical and nontechnical, required for optimal endovascular performance improves, the requisite tools for objective assessment of these skills are being developed and will further enable the use of VR simulation in the training and assessment of endovascular interventionalists and their entire teams. Simulation training that allows deliberate practice without danger to patients may be key to bridging the gap between new endovascular technology and improved patient outcomes. PMID:25792841

  9. Endovascular Thrombolysis Using Monteplase for Non-chronic Deep Venous Thrombosis

    SciTech Connect

    Yamagami, Takuji Yoshimatsu, Rika Tanaka, Osamu Miura, Hiroshi; Nishimura, Tsunehiko

    2010-12-15

    This study was designed to evaluate the usefulness of endovascular thrombolysis using monteplase for deep venous thrombosis (DVT). Between December 2005 and October 2009, at our institution nine endovascular thrombolysis treatments with monteplase were performed for symptomatic DVT in eight patients (6 women, 2 men; mean age, 56 (range, 15-80) years). In all, systemic anticoagulation administered by the peripheral intravenous route with heparin and/or thrombolysis with urokinase followed by anticoagulation with orally administered warfarin had been performed, and subsequently six endovascular treatments without monteplase were administered. However, DVT persisted, and endovascular treatments with monteplase were tried. In six (67%) of the nine procedures, DVT completely or almost completely disappeared after endovascular thrombolysis with monteplase. Mean dose of monteplase used was 2,170,000 IU. There was only one procedure-related complication. In one patient, just after thrombolysis with monteplase, bleeding at the puncture site and gingival bleeding occurred. Bleeding was stopped by manual astriction only. Endovascular thrombolysis with monteplase may be an effective treatment for DVT, even in cases resistant to traditional systemic anticoagulation and thrombolysis and endovascular procedures without monteplase.

  10. Endovascular repair of thoracic aortic aneurysms.

    PubMed

    Cartes-Zumelzu, F; Lammer, J; Kretschmer, G; Hoelzenbein, T; Grabenwöger, M; Thurnher, S

    2000-03-01

    The standard technique for the treatment of descending thoracic aortic aneurysms is elective open surgical repair with graft interposition. This standard approach, although steadily improving, is associated with high morbidity and substantial mortality rates and implies a major surgical procedure with lateral thoracotomy, use of cardiopulmonary bypass, long operation times and a variety of peri- and postoperative complications. This and the success of the first endoluminal treatment of abdominal aortic aneurysms by Parodi et al. prompted the attention to be thrown on the treatment of descending thoracic aortic aneurysms with endoluminal stent-grafts in many large centres. The aim of this new minimally invasive technique is to exclude the aneurysm from blood flow and in consequence to avoid pressure stress on the aneurysmatic aortic wall, by avoiding a large open operation with significant perioperative morbidity. The potentially beneficial effect of this new treatment approach was evaluated in the course of this study. PMID:10875224

  11. Photocatalytic Properties of TiO2 Thin Films Modified with Ag and Pt Nanoparticles Deposited by Gas Flow Sputtering.

    PubMed

    Maicu, M; Glöss, D; Frach, Peter; Hecker, D; Gerlach, G; Córdoba, José M

    2015-09-01

    In this work, a gas flow sputtering (GFS) process which allows the production and deposition of metal nanoparticles (NPs) in a vacuum environment is described. Aim of the study is to prove the potential of this technology for the fabrication of new TiO2 films with enhanced photocatalytic properties. For this purpose, Ag and Pt NPs have been produced and deposited on photocatalytic float glass coated with TiO2 thin films by magnetron sputtering. The influence of the process parameters and of the metal amount on the final properties of the particles (quantity, size, size distribution, oxidation state etc.,) was widely investigated. Moreover, the effect of the NPs on the photocatalytic activity of the resulting materials was evaluated for the case of the decomposition of stearic acid (SA) during UV-A irradiation. The reduction of the water contact angle (WCA) during the irradiation period was measured in order to test the photo-induced super-hydrophilicity (PSH). PMID:26716202

  12. Double-side active TiO2-modified nanofiltration membranes in continuous flow photocatalytic reactors for effective water purification.

    PubMed

    Romanos, G Em; Athanasekou, C P; Katsaros, F K; Kanellopoulos, N K; Dionysiou, D D; Likodimos, V; Falaras, P

    2012-04-15

    A chemical vapour deposition (CVD) based innovative approach was applied with the purpose to develop composite TiO(2) photocatalytic nanofiltration (NF) membranes. The method involved pyrolytic decomposition of titanium tetraisopropoxide (TTIP) vapor and formation of TiO(2) nanoparticles through homogeneous gas phase reactions and aggregation of the produced intermediate species. The grown nanoparticles diffused and deposited on the surface of γ-alumina NF membrane tubes. The CVD reactor allowed for online monitoring of the carrier gas permeability during the treatment, providing a first insight on the pore efficiency and thickness of the formed photocatalytic layers. In addition, the thin TiO(2) deposits were developed on both membrane sides without sacrificing the high yield rates. Important innovation was also introduced in what concerns the photocatalytic performance evaluation. The membrane efficiency to photo degrade typical water pollutants, was evaluated in a continuous flow water purification device, applying UV irradiation on both membrane sides. The developed composite NF membranes were highly efficient in the decomposition of methyl orange exhibiting low adsorption-fouling tendency and high water permeability. PMID:21999989

  13. Phosphate Detection through a Cost-Effective Carbon Black Nanoparticle-Modified Screen-Printed Electrode Embedded in a Continuous Flow System.

    PubMed

    Talarico, Daria; Cinti, Stefano; Arduini, Fabiana; Amine, Aziz; Moscone, Danila; Palleschi, Giuseppe

    2015-07-01

    An automatable flow system for the continuous and long-term monitoring of the phosphate level has been developed using an amperometric detection method based on the use of a miniaturized sensor. This method is based on the monitoring of an electroactive complex obtained by the reaction between phosphate and molybdate that is consequently reduced at the electrode surface. The use of a screen-printed electrode modified with carbon black nanoparticles (CBNPs) leads to the quantification of the complex at low potential, because CBNPs are capable of electrocatalitically enhancing the phosphomolybdate complex reduction at +125 mV versus Ag/AgCl without fouling problems. The developed system also incorporates reagents and waste storage and is connected to a portable potentiostat for rapid detection and quantification of phosphate. Main analytical parameters, such as working potential, reagent concentration, type of cell, and flow rate, were evaluated and optimized. This system was characterized by a low detection limit (6 μM). Interference studies were carried out. Good recovery percentages comprised between 89 and 131.5% were achieved in different water sources, highlighting its suitability for field measurements. PMID:26066782

  14. Simple flow injection for determination of sulfite by amperometric detection using glassy carbon electrode modified with carbon nanotubes-PDDA-gold nanoparticles.

    PubMed

    Amatatongchai, Maliwan; Sroysee, Wongduan; Chairam, Sanoe; Nacapricha, Duangjai

    2015-02-01

    A new approach is presented for sensitive and selective measurement of sulfite (SO3(2-)) in beverages based on a simple flow injection system with amperometric detection. In this work, the sulfite sensor was a glassy carbon electrode modified with multiwall carbon nanotubes-poly(diallyldimethylammonium chloride)-gold nanoparticles composites (CNTs-PDDA-AuNPs/GC). Electrochemical oxidation of sulfite with this electrode was first studied in 0.1M phosphate buffer (pH 7.0) using cyclic voltammetry. The results indicated that the CNTs-PDDA-AuNPs/GC electrode possesses electrocatalytic activity for the oxidation of sulfite with high sensitivity and selectivity. Sulfite was quantified using amperometric measurement with the new sensor at +0.4V vs Ag/AgCl in conjunction with flow injection. The linear working range for the quantitation of sulfite was 2-200 mg L(-1) (r(2)=0.998) with a detection limit of 0.03 mg L(-1) (3σ of blank) and an estimated precision of 1.5%.The proposed method was successfully applied to the determination of sulfite in fruit juices and wines with a sample throughput of 23 samples per hour. PMID:25435239

  15. Development of a Rapid Immunochromatographic Lateral Flow Device Capable of Differentiating Phytase Expressed from Recombinant Aspergillus niger phyA2 and Genetically Modified Corn.

    PubMed

    Zhou, Xiaojin; Hui, Elizabeth; Yu, Xiao-Lin; Lin, Zhen; Pu, Ling-Kui; Tu, Zhiguan; Zhang, Jun; Liu, Qi; Zheng, Jian; Zhang, Juan

    2015-05-01

    Phytase is a phosphohydrolase considered highly specific for the degradation of phytate to release bound phosphorus for animal consumption and aid in the reduction of environmental nutrient loading. New sources of phytase have been sought that are economically and efficiently productive including the construction of genetically modified (GM) phytase products designed to bypass the costs associated with feed processing. Four monoclonal antibodies (EH10a, FA7, AF9a, and CC1) raised against recombinant Aspergillus niger phyA2 were used to develop a highly specific and sensitive immunochromatographic lateral flow device for rapid detection of transgenic phytase, such as in GM corn. Antibodies sequentially paired and tested along lateral flow strips showed that the EH10a-FA7 antibody pair was able to detect the recombinant yeast-phytase at 5 ng/mL, whereas the AF9a-CC1 antibody pair to GM phytase corn was able to detect at 2 ng/mL. Concurrent to this development, evidence was revealed which suggests that antibody binding sites may be glycosylated. PMID:25901899

  16. Lower Extremity Microembolism in Open vs. Endovascular Abdominal Aortic Aneurysm Repair

    PubMed Central

    Toursavadkohi, Shahab; Kakkos, Stavros K.; Rubinfeld, Ilan; Shepard, Alexander

    2016-01-01

    Although previous studies have documented the occurrence of microembolization during abdominal aortic aneurysm (AAA) repair by both open and endovascular approaches, no study has compared the downstream effects of these two repair techniques on lower extremity hemodynamics. In this prospective cohort study, 20 patients were treated with endovascular aneurysm repair (EVAR) (11 Zenith, 8 Excluder, and 1 Medtronic) and 18 patients with open repair (OR) (16 bifurcated grafts, 2 tube grafts). Pre- and postoperative ankle-brachial indices (ABIs) and toe-brachial indices (TBIs) were measured preoperatively and on postoperative day (POD) 1 and 5. Demographics and preoperative ABIs/TBIs were identical in EVAR (0.97/0.63) and OR (0.96/0.63) patients (p = 0.21). There was a significant decrease in ABIs/TBIs following both EVAR (0.83/0.52, p = 0.01) and OR (0.73/0.39, p = 0.003) on POD #1, although this decrease was greater following OR than EVAR (p = 0.002). This difference largely resolved by POD #5 (p = 0.41). In the OR group, TBIs in the limb in which flow was restored first was significantly reduced compared to the contralateral limb (0.50 vs. 0.61, p = 0.03). In the EVAR group, there was also a difference in TBIs between the main body insertion side and the contralateral side (0.50 vs. 0.59, p = 0.02). Deterioration of lower extremity perfusion pressures occurs commonly after AAA repair regardless of repair technique. Toe perfusion is worse in the limb opened first during OR and on the main body insertion side following EVAR, suggesting that microembolization plays a major role in this deterioration. The derangement following OR is more profound than after EVAR on POD #1, but recovers rapidly. This finding suggests that microembolizarion may be worse with OR or alternatively that other factors associated with OR (e.g., the hemodynamic response to surgery with redistribution of flow to vital organs peri-operatively) may play a role. PMID

  17. Lower Extremity Microembolism in Open vs. Endovascular Abdominal Aortic Aneurysm Repair.

    PubMed

    Toursavadkohi, Shahab; Kakkos, Stavros K; Rubinfeld, Ilan; Shepard, Alexander

    2016-01-01

    Although previous studies have documented the occurrence of microembolization during abdominal aortic aneurysm (AAA) repair by both open and endovascular approaches, no study has compared the downstream effects of these two repair techniques on lower extremity hemodynamics. In this prospective cohort study, 20 patients were treated with endovascular aneurysm repair (EVAR) (11 Zenith, 8 Excluder, and 1 Medtronic) and 18 patients with open repair (OR) (16 bifurcated grafts, 2 tube grafts). Pre- and postoperative ankle-brachial indices (ABIs) and toe-brachial indices (TBIs) were measured preoperatively and on postoperative day (POD) 1 and 5. Demographics and preoperative ABIs/TBIs were identical in EVAR (0.97/0.63) and OR (0.96/0.63) patients (p = 0.21). There was a significant decrease in ABIs/TBIs following both EVAR (0.83/0.52, p = 0.01) and OR (0.73/0.39, p = 0.003) on POD #1, although this decrease was greater following OR than EVAR (p = 0.002). This difference largely resolved by POD #5 (p = 0.41). In the OR group, TBIs in the limb in which flow was restored first was significantly reduced compared to the contralateral limb (0.50 vs. 0.61, p = 0.03). In the EVAR group, there was also a difference in TBIs between the main body insertion side and the contralateral side (0.50 vs. 0.59, p = 0.02). Deterioration of lower extremity perfusion pressures occurs commonly after AAA repair regardless of repair technique. Toe perfusion is worse in the limb opened first during OR and on the main body insertion side following EVAR, suggesting that microembolization plays a major role in this deterioration. The derangement following OR is more profound than after EVAR on POD #1, but recovers rapidly. This finding suggests that microembolizarion may be worse with OR or alternatively that other factors associated with OR (e.g., the hemodynamic response to surgery with redistribution of flow to vital organs peri-operatively) may play a role. PMID

  18. Late Recurrence of a Hepatic Artery Aneurysm After Treatment Using an Endovascular Stent

    SciTech Connect

    Downer, Jonathan; Choji, Kiyoshi

    2008-11-15

    Endovascular stent placement and coil embolization have become established options in the treatment of visceral arterial aneurysms. In this article we report the case of an 83-year-old presenting with gastrointestinal hemorrhage due to a recurrent hepatic arterial aneurysm occurring 12 years after treatment with an endovascular stent. The recurrent aneurysm had resulted from stent fracture and was successfully treated by coil embolization. To our knowledge, stent fracture complicating the endovascular treatment of a visceral artery aneurysm has not been described in the published literature. With the increasing use of metallic endoprostheses in interventional radiology, recognizing and reporting device failure are of critical importance.

  19. Endovascular Stent-Graft Repair as a Late Secondary Procedure After Previous Aortic Grafts

    SciTech Connect

    Matsagas, Miltiadis I. Anagnostopoulos, Constantine E.; Papakostas, John C.; DeRose, Joseph J.; Siminelakis, Stavros; Katsouras, Christos S.; Toumpoulis, Ioannis K.; Drossos, George E.; Michalis, Lampros K.

    2006-08-15

    Thoracic and abdominal aortic endovascular procedures as alternatives to aortic reoperations were studied in three different cases. An anastomotic aneurysm after previous thoracic aortic graft for coarctation, a second-stage elephant trunk repair (descending thoracic aortic aneurysm), and a secondary aneurysm proximal to a previous abdominal aortic graft were successfully treated with endovascular stent-grafts. During the follow-up period no lethal events or major aortic or graft-related complications were observed, except a type II endoleak in the anastomotic aortic aneurysm case. An endovascular stent-graft can be safely deployed into a previously implanted vascular graft, avoiding repeat surgery.

  20. Protective effect of angulated aorta for saving coronary artery during endovascular repair for ascending aortic pseudoaneurysm

    PubMed Central

    Kim, Myeong Gun; Oh, Pyung Chun; Jeon, Yang Bin; Lee, Ji Yeon; Shin, Eak Kyun

    2016-01-01

    Ascending aortic pseudoaneurysm is a rare complication after cardiothoracic surgery and the open surgical repair for this complication is challenging. We report on a patient who developed an ascending aortic pseudoaneurysm after aortic valve replacement (AVR), which was treated successfully with endovascular therapy. Our case showed that angulation of the ascending aorta is one of factors for consideration in application of endovascular therapy and endovascular therapy might be an option for management of ascending aortic pathology in patients with high surgical risk, particularly patients with a severely angulated proximal ascending aorta. PMID:27621896

  1. A Case of Disseminated Intravascular Coagulation after Thoracic Endovascular Aortic Repair

    PubMed Central

    2015-01-01

    I report a hemorrhagic complication due to disseminated intravascular coagulation after thoracic endovascular aortic repair for a dissecting aortic aneurysm. A 74-year-old man underwent thoracic endovascular aortic repair and carotid-carotid artery bypass to close the primary entry site of the dissecting aortic aneurysm. Postoperatively, he developed a gradually expanding cervical hematoma. Laboratory data showed disseminated intravascular coagulation. He could not extubated until postoperative day 6 because of the risk of airway obstruction. He was treated with transfusion to replenish the coagulation factor. Disseminated intravascular coagulation may occur secondary to thrombus formation in the false lumen after thoracic endovascular aortic repair. PMID:26730263

  2. A New Murine Model of Endovascular Aortic Aneurysm Repair

    PubMed Central

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

    2013-01-01

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

  3. Endovascular Treatment of Mycotic Aortic Pseudoaneurysms with Stent-Grafts

    SciTech Connect

    Tiesenhausen, Kurt Hessinger, Michael; Tomka, Maurice; Portugaller, Horst; Swanidze, Shota; Oberwalder, Peter

    2008-05-15

    Mycotic aortic aneurysms remain a therapeutic challenge, especially in patients who are not suitable for open surgery. Endovascular treatment with stent-grafts in this indication is still disputed. Between January 2002 and January 2006, six patients with mycotic aneurysms of the thoracoabdominal or abdominal aorta were admitted to our department. All patients were male, aged 57-83 years (mean, 74.6 years). The mycotic aneurysms were diagnosed on the basis of clinical signs of infection, on CT, and, in four cases, on a positive blood culture. In all patients the mycotic aortic aneurysms were treated endovascularly by stent-graft implantation. Technical and clinical success was achieved in all patients. There was no in-hospital or 30-day mortality. In the follow-up period (range, 2-47 months) four patients died of cancer, cardiac failure, or unknown cause (one case). Two patients are still alive with nearly complete regression of the aneurysms. We conclude that treatment of mycotic aortic aneurysms with stent-grafts may be an alternative in selected patients.

  4. Endovascular Stent-Grafting for Infected Iliac Artery Pseudoaneurysms

    SciTech Connect

    Sanada, Junichiro Matsui, Osamu; Arakawa, Fumitaka; Tawara, Mari; Endo, Tamao; Ito, Hiroshi; Ushijima, Satoshi; Endo, Masamitsu; Ikeda, Masahiro; Miyazu, Katsuyuki

    2005-01-15

    We report two cases of acutely infected pseudoaneurysms of the iliac arteries, successfully treated with endovascular stent-grafting. Two patients underwent stent-graft treatment for erosive rupture of the iliac artery caused by surrounding infection. The first case is that of a 61-year-old man who had undergone Miles' operation for an advanced rectal cancer. Postoperatively, he developed intrapelvic abscess formation, from which methicillin-resistant Staphylococcus aureus was cultured, followed by rupture of the right external iliac artery. The second case is that of a 60-year-old man who had a pseudoaneurysm of the left common iliac artery, which was contiguous with a left psoas muscle abscess, from which Streptococcus agalactiae was cultured. Both patients were successfully treated with only a stent-graft and antibiotic therapy, and remained symptom-free 12 months and 10 months later. Although endovascular stent-grafting should not be considered standard therapy for infected aneurysms, our cases suggest that it can result in repair of infected aneurysms even in the uncontrolled active stage.

  5. Endovascular Techniques for the Treatment of Renal Artery Aneurysms

    SciTech Connect

    Elaassar, Omar Auriol, Julien; Marquez, Romero; Tall, Philippe; Rousseau, Herve; Joffre, Francis

    2011-10-15

    Purpose: Our goal was to analyze the indications and limitations of the different percutaneous endovascular approaches reported for the treatment of renal artery aneurysms (RAAs) and to develop a scientific approach for optimum selection of treatment strategy of RAAs through analyzing our experience and reviewing available literature. Methods: This retrospective study was designed to evaluate the treatment and follow-up of 13 consecutive patients who presented with 13 RAAs by using a variety of endovascular interventional techniques. Different combinations of coil embolization, liquid embolization, stenting, and stent-graft exclusion were used in correlation with variable-specific aneurysm criteria. Results: All patients were successfully treated with no significant short- or long-term complications. Patients were followed for an average period of 43 (range 13-103) months. Conclusions: Ten different determinants were found to affect our decision making: shape, size, neck, position of aneurysm on artery, branches arising, artery involved, condition of the artery, age, general condition of the patient, and renal function.

  6. [Debranch Thoracic Endovascular Aortic Therapy for Extending Aneurysms].

    PubMed

    Miyamoto, Shinji

    2016-07-01

    To apply endovascular aortic repair for arch or thoracoabdominal pathology, it is essential to reconstruct the branches originating in the treatment area. In cases that a stentgraft has to reach ascending aorta we perform "in situ fenestration with squid capture technique".During the procedure cerebral circulation is maintained by percutaneous cardiopulmonary bypass. After deploying the stentgraft we stab it by a needle while squeezed by snare wire and stick a covered stentgraft eventually. Unlike chimney technique which also can be applied for zone 0 thoracic endovascular aortic therapy( TEVAR),this method has no risk of gutter leak. For now there are no fenestrated nor branched grafts in Japan so that we should perform hybrid TEVAR for throacoabdominal aneurysms if patients' conditions cannot allow graft replacement. In such a case we make bypasses between the common iliac artery( or left leg of bifurcated graft) and visceral arteries using a quadrated graft. All anastomosis can be done in a retroperitoneal single plane. TEVAR shouldn't be performed simultaneously with bypass because unstable hemodynamic increase risk of paraplegia. We have never experienced paraplegia among 50 cases except for 1 case in which TEVAR had to be done urgently under critical hypotension. PMID:27440024

  7. Postcatheterization Femoral Arteriovenous Fistulas: Endovascular Treatment with Stent-Grafts

    SciTech Connect

    Onal, Baran Kosar, Sule; Gumus, Terman; Ilgit, Erhan T.; Akpek, Sergin

    2004-09-15

    Purpose: To report our results of stent-graft implantation for the endovascular treatment of postcatheterization femoral arteriovenous fistulas (AVFs) occurring between the deep femoral artery and the femoral vein.Methods: Endovascular treatment of iatrogenic femoral AVFs as a result of arterial puncture for coronary angiography and/or angioplasty was attempted in 10 cases. Balloon-expandable stent-grafts, one for each lesion, were used to repair the fistulas, which were between the deep femoral artery and the femoral vein in all cases. Stent-graft implantation to the deep femoral artery was performed by a contralateral retrograde approach.Results: All stent-grafts were deployed successfully. Complete closure of the fistulas was accomplished immediately in nine of 10 cases. In one case, complete closure could not be obtained but the fact that the complaint subsided was taken to indicate clinical success. In three cases, side branch occlusion of the deep femoral artery occurred. No complications were observed after implantation. Follow-up for 8-31 months (mean 18.5 months) with color Doppler ultrasonography revealed patency of the stented arterial segments without recurrent arteriovenous shunting in those nine patients who had successful immediate closure of their AVFs.Conclusion: Our results with a mean follow-up 18.5 months suggest that stent-graft implantation for the closure of postcatheterization femoral AVFs originating from the deep femoral artery is an effective, minimally invasive alternative procedure.

  8. Effects of tripterygium glycosides on restenosis following endovascular treatment

    PubMed Central

    HAN, BING; GE, CHANG-QING; ZHANG, HONG-GUANG; ZHOU, CHEN-GUANG; JI, GUO-HUI; YANG, ZHENG; ZHANG, LIANG

    2016-01-01

    The mechanism and associated factors of restenosis following intravascular stent implantation remain to be elucidated. The present two-part experimental and clinical study aimed to investigate the effects of tripterygium glycosides on in-stent restenosis subsequent to intra-arterial therapy. Following endovascular stent implantation in rabbit iliac arteries, post-stent outcomes were evaluated in cyclosporine groups, low-dose and high-dose tripterygium glycosides groups and controls. Post-operative angiography indicated that vessel diameters were similar between groups; however, at 28 days after receiving the therapeutic agents, vessels of the cyclosporine and tripterygium glycosides groups were significantly larger than those of the controls. Furthermore, three groups of patients had comparable baseline levels of interleukin (IL)-10, IL-18 and C-reactive protein, and intima-media thickness. However, 1 month after stent implantation, levels of IL-10 and IL-18 were markedly reduced in the high- and low-dose tripterygium glycosides groups compared with controls. At 6 months after surgery, the stent patency rate in patients with bare stents was significantly lower than in patients receiving tripterygium glycosides (P≤0.009). In addition, the ankle-brachial index was also higher than in those without tripterygium glycosides (P<0.001). Results of the experimental and clinical studies suggest that tripterygium glycosides may inhibit and possibly aid in the prevention of in-stent restenosis formation following endovascular treatment of lower-extremity artery disease. PMID:27108914

  9. Metal-induced generalized pruriginous dermatitis and endovascular surgery.

    PubMed

    Giménez-Arnau, A; Riambau, V; Serra-Baldrich, E; Camarasa, J G

    2000-07-01

    Metal contact allergy is a common problem in the general population. Diagnostic and therapeutic medical-surgical procedures in which metals can be responsible for eczema are diverse. Endovascular aortic surgery is still an experimental but less invasive technique. A generalized eczematous dermatitis elicited by metal of an endovascular prosthesis is presented. An abdominal aortic aneurysm was diagnosed in a 79-year-old woman. Endoluminal repair with a straight Vanguard endograft was successful. 3 weeks later, she suffered a severe episode of erythema and eczema on the legs. Since then, she complained of continuous pruritus with eczema and excoriated papules. The dermatitis and also the patch test pathology showed eczema. Patch testing was positive to nickel sulfate and cobalt chloride. An endograft semi-quantitative metal analysis was performed with plasma-induction joint mass-spectrometry. The self-expanding metal stent was mainly composed of nickel (approximately 55%) and titanium (21%) with reinforcing thread of platinum. Antimony was detected only in the polyester textile. These results are consistent with Nitinol composition. The need for preoperative patch testing for metals is controversial. Enquiry about metal allergy is recommended before endoluminal surgical procedures. In the near future, the design of endografts must take into account the possibility of this sort of reaction. PMID:10902587

  10. Endovascular Treatment of Behcet Disease With Recurrent Infrainguinal Arterial Pseudoaneurysms

    PubMed Central

    Ding, Ze-yang; Jin, Guan-nan; Ai, Xi; Li, Li-yan; Zheng, Ping; Guan, Yan; Wang, Qi; Zhang, Zhi-wei; Yang, Jun

    2016-01-01

    Abstract Aneurysm or pseudoaneurysm formation is one of the vascular complications of Behcet disease. At present, the optimal treatment for the disease has not been established. The authors report a case of vasculo-Behcet disease (v-BD) with recurrent pseudoaneurysms in the left infrainguinal arteries (common femoral artery, superficial femoral artery, and popliteal artery), as well as thrombosis in the popliteal vein and posterior tibial vein. The patient underwent 3 rounds of surgery, but developed a new pseudoaneurysm several months after each surgery. Eventually, the patient was successfully treated with a combination of endovascular repair, using a fully covered stent graft, and prednisone. The pseudoaneurysm regressed without recurrence for more than 1 year. For v-BD, treatment with immunosuppressive therapy alone may not be sufficient to prevent the recurrence of pseudoaneurysms. For the endovascular treatment of pseudoaneurysms affecting the infrainguinal arteries in v-BD, a fully covered stent graft without oversizing is essential to prevent the recurrence of pseudoaneurysms. PMID:27175653

  11. Endovascular aortic injury repair after thoracic pedicle screw placement.

    PubMed

    Pesenti, S; Bartoli, M A; Blondel, B; Peltier, E; Adetchessi, T; Fuentes, S

    2014-09-01

    Our objective was to describe the management and prevention of thoracic aortic injuries caused by a malposition of pedicle screws in corrective surgery of major spine deformities. Positioning pedicle screws in thoracic vertebras by posterior approach exposes to the risk of injury of the elements placed ahead of the thoracic spine, as the descending thoracic aorta. This complication can result in a cataclysmic bleeding, needing urgent vascular care, but it can also be totally asymptomatic, resulting in the long run in a pseudoaneurysm, justifying the systematic removal of the hardware. We report the case of a 76-year-old woman who underwent spinal correction surgery for thoraco-lumbar degenerative kypho-scoliosis. Immediately after the surgery, a thoracic aortic injury caused by the left T7 pedicle screw was diagnosed. The patient underwent a two-step surgery. The first step was realized by vascular surgeons and aimed to secure the aortic wall by short endovascular aortic grafting. During the second step, spine surgeons removed the responsible screw by posterior approach. The patient was discharged in a rehabilitation center 7 days after the second surgery. When such a complication occurs, a co-management by vascular and spine surgeons is necessary to avoid major complications. Endovascular management of this kind of vascular injuries permits to avoid an open surgery that have a great rate of morbi-mortality in frail patients. Nowadays, technologies exist to prevent this kind of event and may improve the security when positioning pedicle screws. PMID:25023930

  12. Emergent Endovascular Stent Grafts for Ruptured Aortic Aneurysms.

    PubMed

    Montgomery, Jennifer P; Kolbeck, Kenneth J; Kaufman, John A

    2015-09-01

    Ruptured aortic aneurysms uniformly require emergent attention. Historically, urgent surgical repair or medical management was the only treatment options. The development of covered stent grafts has introduced a third approach in the care of these critical patients. The clinical status of the patient and local physician expertise drive the treatment modalities in the majority of cases. The goal of therapy in these patients is to stabilize the patient as quickly as possible, establish maximum survival with minimum morbidity, and provide a long lasting result. The endovascular approach has become an acceptable treatment option in an increasing number of patients presenting with ruptured aneurysmal disease of both the descending thoracic and abdominal aorta. Major factors influencing treatment include patient clinical status, characteristics of the aorta, physician preference, institutional experience, and availability of appropriate equipment. Planning, experience, and the ability to improvise effective solutions are keys to the success of the procedure when endovascular techniques are utilized. Three separate cases, requiring intraprocedural improvisation, are presented followed by a review of the literature. PMID:26327743

  13. Effects of tripterygium glycosides on restenosis following endovascular treatment.

    PubMed

    Han, Bing; Ge, Chang-Qing; Zhang, Hong-Guang; Zhou, Chen-Guang; Ji, Guo-Hui; Yang, Zheng; Zhang, Liang

    2016-06-01

    The mechanism and associated factors of restenosis following intravascular stent implantation remain to be elucidated. The present two‑part experimental and clinical study aimed to investigate the effects of tripterygium glycosides on in‑stent restenosis subsequent to intra‑arterial therapy. Following endovascular stent implantation in rabbit iliac arteries, post‑stent outcomes were evaluated in cyclosporine groups, low‑dose and high‑dose tripterygium glycosides groups and controls. Post‑operative angiography indicated that vessel diameters were similar between groups; however, at 28 days after receiving the therapeutic agents, vessels of the cyclosporine and tripterygium glycosides groups were significantly larger than those of the controls. Furthermore, three groups of patients had comparable baseline levels of interleukin (IL)‑10, IL‑18 and C‑reactive protein, and intima‑media thickness. However, 1 month after stent implantation, levels of IL‑10 and IL‑18 were markedly reduced in the high‑ and low‑dose tripterygium glycosides groups compared with controls. At 6 months after surgery, the stent patency rate in patients with bare stents was significantly lower than in patients receiving tripterygium glycosides (P≤0.009). In addition, the ankle‑brachial index was also higher than in those without tripterygium glycosides (P<0.001). Results of the experimental and clinical studies suggest that tripterygium glycosides may inhibit and possibly aid in the prevention of in‑stent restenosis formation following endovascular treatment of lower‑extremity artery disease. PMID:27108914

  14. Electromagnetic Treatment to Old Alzheimer's Mice Reverses β-Amyloid Deposition, Modifies Cerebral Blood Flow, and Provides Selected Cognitive Benefit

    PubMed Central

    Arendash, Gary W.; Mori, Takashi; Dorsey, Maggie; Gonzalez, Rich; Tajiri, Naoki; Borlongan, Cesar

    2012-01-01

    Few studies have investigated physiologic and cognitive effects of “long-term" electromagnetic field (EMF) exposure in humans or animals. Our recent studies have provided initial insight into the long-term impact of adulthood EMF exposure (GSM, pulsed/modulated, 918 MHz, 0.25–1.05 W/kg) by showing 6+ months of daily EMF treatment protects against or reverses cognitive impairment in Alzheimer's transgenic (Tg) mice, while even having cognitive benefit to normal mice. Mechanistically, EMF-induced cognitive benefits involve suppression of brain β-amyloid (Aβ) aggregation/deposition in Tg mice and brain mitochondrial enhancement in both Tg and normal mice. The present study extends this work by showing that daily EMF treatment given to very old (21–27 month) Tg mice over a 2-month period reverses their very advanced brain Aβ aggregation/deposition. These very old Tg mice and their normal littermates together showed an increase in general memory function in the Y-maze task, although not in more complex tasks. Measurement of both body and brain temperature at intervals during the 2-month EMF treatment, as well as in a separate group of Tg mice during a 12-day treatment period, revealed no appreciable increases in brain temperature (and no/slight increases in body temperature) during EMF “ON" periods. Thus, the neuropathologic/cognitive benefits of EMF treatment occur without brain hyperthermia. Finally, regional cerebral blood flow in cerebral cortex was determined to be reduced in both Tg and normal mice after 2 months of EMF treatment, most probably through cerebrovascular constriction induced by freed/disaggregated Aβ (Tg mice) and slight body hyperthermia during “ON" periods. These results demonstrate that long-term EMF treatment can provide general cognitive benefit to very old Alzheimer's Tg mice and normal mice, as well as reversal of advanced Aβ neuropathology in Tg mice without brain heating. Results further underscore the potential for EMF

  15. Cerebral infarct volume measurements to improve patient selection for endovascular treatment

    PubMed Central

    Han, Miran; Choi, Jin Wook; Rim, Nae-Jung; Kim, Sun Yong; Suh, Hong-Il; Lee, Kyu Sun; Hong, Ji Man; Lee, Jin Soo

    2016-01-01

    Abstract Patients who have large cerebral infarctions may not be good candidates for endovascular treatment. Various methods for determining infarct volume have been used in clinical studies. We evaluated the effectiveness of several methods for measuring infarct volume, especially regarding futile outcomes despite endovascular treatment. Patients with acute ischemic stroke in unilateral anterior circulation territory who were treated with intra-arterial thrombectomy were included. For assessing infarct volume, the Alberta Stroke Program Early Computed Tomography Score (ASPECTS) scoring system was applied to images obtained by noncontrast computed tomography (NCCT), postcontrast CT (PCCT), and diffusion-weighted imaging (DWI). DWI stroke volume was semiquantitatively measured with the manually outlined hyperintense lesion. Infarct core volume was calculated with a threshold apparent diffusion coefficient value of 600 × 10–6 mm2/s. Intraclass correlation coefficients (ICC) were estimated to assess inter-reader reliability for ASPECTS scoring and DWI stroke volume. Receiver operating characteristic (ROC) curve analyses, and univariable and multivariable comparative analyses, were performed with each evaluation method to predict futile outcome (modified Rankin Scale score 5–6). The mean age of the included 79 patients was 65.1 ± 15.7 years. Among them, 55 (69.6%) patients demonstrated successful reperfusion after intra-arterial thrombectomy, but 34 (43.0%) patients had futile outcomes. Inter-reader agreement was excellent for measurement of the DWI stroke volume (ICC, 0.973), DWI ASPECTS (0.940), and PCCT ASPECTS (0.859), but was moderate for NCCT ASPECTS (0.694). Regarding prediction of futile outcomes, area under ROC curve was 0.551 on NCCT ASPECTS and it was significantly smaller than that in PCCT ASPECTS (area under ROC 0.651, P = 0.030), DWI ASPECTS (0.733, P = 0.003), DWI stroke volume (0.702, P = 0.022), and infarct core volume (0

  16. Cerebral infarct volume measurements to improve patient selection for endovascular treatment.

    PubMed

    Han, Miran; Choi, Jin Wook; Rim, Nae-Jung; Kim, Sun Yong; Suh, Hong-Il; Lee, Kyu Sun; Hong, Ji Man; Lee, Jin Soo

    2016-08-01

    Patients who have large cerebral infarctions may not be good candidates for endovascular treatment. Various methods for determining infarct volume have been used in clinical studies. We evaluated the effectiveness of several methods for measuring infarct volume, especially regarding futile outcomes despite endovascular treatment.Patients with acute ischemic stroke in unilateral anterior circulation territory who were treated with intra-arterial thrombectomy were included. For assessing infarct volume, the Alberta Stroke Program Early Computed Tomography Score (ASPECTS) scoring system was applied to images obtained by noncontrast computed tomography (NCCT), postcontrast CT (PCCT), and diffusion-weighted imaging (DWI). DWI stroke volume was semiquantitatively measured with the manually outlined hyperintense lesion. Infarct core volume was calculated with a threshold apparent diffusion coefficient value of 600 × 10 mm/s. Intraclass correlation coefficients (ICC) were estimated to assess inter-reader reliability for ASPECTS scoring and DWI stroke volume. Receiver operating characteristic (ROC) curve analyses, and univariable and multivariable comparative analyses, were performed with each evaluation method to predict futile outcome (modified Rankin Scale score 5-6).The mean age of the included 79 patients was 65.1 ± 15.7 years. Among them, 55 (69.6%) patients demonstrated successful reperfusion after intra-arterial thrombectomy, but 34 (43.0%) patients had futile outcomes. Inter-reader agreement was excellent for measurement of the DWI stroke volume (ICC, 0.973), DWI ASPECTS (0.940), and PCCT ASPECTS (0.859), but was moderate for NCCT ASPECTS (0.694). Regarding prediction of futile outcomes, area under ROC curve was 0.551 on NCCT ASPECTS and it was significantly smaller than that in PCCT ASPECTS (area under ROC 0.651, P = 0.030), DWI ASPECTS (0.733, P = 0.003), DWI stroke volume (0.702, P = 0.022), and infarct core volume (0.702, P = 0

  17. A Modified EPA Method 1623 that Uses Tangential Flow Hollow-fiber Ultrafiltration and Heat Dissociation Steps to Detect Waterborne Cryptosporidium and Giardia spp.

    PubMed Central

    Rhodes, Eric R.; Villegas, Leah Fohl; Shaw, Nancy J.; Miller, Carrie; Villegas, Eric N.

    2012-01-01

    Cryptosporidium and Giardia species are two of the most prevalent protozoa that cause waterborne diarrheal disease outbreaks worldwide. To better characterize the prevalence of these pathogens, EPA Method 1623 was developed and used to monitor levels of these organisms in US drinking water supplies 12. The method has three main parts; the first is the sample concentration in which at least 10 L of raw surface water is filtered. The organisms and trapped debris are then eluted from the filter and centrifuged to further concentrate the sample. The second part of the method uses an immunomagnetic separation procedure where the concentrated water sample is applied to immunomagnetic beads that specifically bind to the Cryptosporidium oocysts and Giardia cysts allowing for specific removal of the parasites from the concentrated debris. These (oo)cysts are then detached from the magnetic beads by an acid dissociation procedure. The final part of the method is the immunofluorescence staining and enumeration where (oo)cysts are applied to a slide, stained, and enumerated by microscopy. Method 1623 has four listed sample concentration systems to capture Cryptosporidium oocysts and Giardia cysts in water: Envirochek filters (Pall Corporation, Ann Arbor, MI), Envirochek HV filters (Pall Corporation), Filta-Max filters (IDEXX, Westbrook, MA), or Continuous Flow Centrifugation (Haemonetics, Braintree, MA). However, Cryptosporidium and Giardia (oo)cyst recoveries have varied greatly depending on the source water matrix and filters used1,14. A new tangential flow hollow-fiber ultrafiltration (HFUF) system has recently been shown to be more efficient and more robust at recovering Cryptosporidium oocystsand Giardia cysts from various water matrices; moreover, it is less expensive than other capsule filter options and can concentrate multiple pathogens simultaneously1-3,5-8,10,11. In addition, previous studies by Hill and colleagues demonstrated that the HFUF significantly improved

  18. A modified EPA Method 1623 that uses tangential flow hollow-fiber ultrafiltration and heat dissociation steps to detect waterborne Cryptosporidium and Giardia spp.

    PubMed

    Rhodes, Eric R; Villegas, Leah Fohl; Shaw, Nancy J; Miller, Carrie; Villegas, Eric N

    2012-01-01

    Cryptosporidium and Giardia species are two of the most prevalent protozoa that cause waterborne diarrheal disease outbreaks worldwide. To better characterize the prevalence of these pathogens, EPA Method 1623 was developed and used to monitor levels of these organisms in US drinking water supplies (12). The method has three main parts; the first is the sample concentration in which at least 10 L of raw surface water is filtered. The organisms and trapped debris are then eluted from the filter and centrifuged to further concentrate the sample. The second part of the method uses an immunomagnetic separation procedure where the concentrated water sample is applied to immunomagnetic beads that specifically bind to the Cryptosporidium oocysts and Giardia cysts allowing for specific removal of the parasites from the concentrated debris. These (oo)cysts are then detached from the magnetic beads by an acid dissociation procedure. The final part of the method is the immunofluorescence staining and enumeration where (oo)cysts are applied to a slide, stained, and enumerated by microscopy. Method 1623 has four listed sample concentration systems to capture Cryptosporidium oocysts and Giardia cysts in water: Envirochek filters (Pall Corporation, Ann Arbor, MI), Envirochek HV filters (Pall Corporation), Filta-Max filters (IDEXX, Westbrook, MA), or Continuous Flow Centrifugation (Haemonetics, Braintree, MA). However, Cryptosporidium and Giardia (oo)cyst recoveries have varied greatly depending on the source water matrix and filters used(1,14). A new tangential flow hollow-fiber ultrafiltration (HFUF) system has recently been shown to be more efficient and more robust at recovering Cryptosporidium oocysts and Giardia cysts from various water matrices; moreover, it is less expensive than other capsule filter options and can concentrate multiple pathogens simultaneously(1-3,5-8,10,11). In addition, previous studies by Hill and colleagues demonstrated that the HFUF significantly

  19. Wire-Loop Technique for Stabilizing Catheters over the Aortic Bifurcation for Endovascular Intervention

    SciTech Connect

    Viner, Stuart Kessel, David

    2008-07-15

    We describe a simple technique to perform difficult endovascular interventions safely by using a wire-loop guidewire over the aortic bifurcation. This guidewire is then used to stabilize catheters for stenting or embolization.

  20. Recovery of Third Nerve Palsy after Endovascular Packing of Internal Carotid-Posterior Communicating Artery Aneurysms

    PubMed Central

    Mavilio, N.; Pisani, R.; Rivano, C.; Testa, V.; Spaziante, R.; Rosa, M.

    2000-01-01

    Summary Endovascular packing of intracranial aneurysm with preservation of the parent vessel has become in many cases a valid alternative to surgical clipping. Regression of oculomotor disorders after clipping of internal carotid-posterior communicating artery (ICA-PCoA) aneurysms has been well assessed. This report focuses on the reversal of third nerve palsy after endovascular packing of ICA-PCoA aneurysms. To this end, clinical appearances, neuroradiological features, and endovascular interventional procedures of six treated patient are reported and discussed in the light of the very few previous case observations found in the literature. Results indicate that endovascular packing of ICA-PCoA aneurysms may produce effective recovery of correlated third nerve dysfunction. PMID:20667199

  1. Endovascular Repair of a Traumatic Axillary Pseudoaneurysm Following Anterior Shoulder Dislocation

    SciTech Connect

    Stahnke, Michaela; Duddy, Martin J.

    2006-04-15

    Pseudoaneurysms due to musculoskeletal trauma are rare and comprise less than 2% of all pseudoaneurysms. We report a case of axillary pseudoaneurysm following anterior dislocation of the shoulder. The patient was successfully treated by endovascular intervention.

  2. Therapeutic algorithm to treat common iliac artery aneurysms by endovascular means.

    PubMed

    Panuccio, Giuseppe; Torsello, Giovanni F; Torsello, Giovanni B; Donas, Konstantinos P

    2016-10-01

    Use of endovascular means is gaining ever greater acceptance in the treatment of aorto-iliac aneurysms. Especially, the treatment of patients with common iliac aneurysms (CIAs) may be very challenging due to the complexity of the underlying disease with often involvement of the hypogastric artery. Additionally, the variety of endovascular therapeutic options such as the use of iliac branch devices, parallel grafts, the bell-bottom technique or coil embolization of the hypogastric artery and overstenting of the origin represents significant limitation regarding the presentation of a clear and robust endovascular therapeutic algorithm. Aim of the present article was the demonstration of the institutional experience with the endovascular management of CIAs in order to provide a clinical recommendation and algorithm. PMID:27406396

  3. Computed tomography angiography of hybrid thoracic endovascular aortic repair of the aortic arch.

    PubMed

    Akhtar, Nila J; Oderich, Gustavo S; Vrtiska, Terri J; Williamson, Eric E; Araoz, Philip A

    2013-05-01

    Endovascular repair of the aorta has traditionally been limited to the abdominal aorta and, more recently, the descending thoracic aorta. However, recently hybrid repairs (a combination of open surgical and endovascular repair) have made endovascular repair of the aortic arch possible. Hybrid repair of the aortic arch typically involves an open surgical debranching procedure that allows for revascularization of the aortic arch vessels and subsequent endovascular stent placement. These approaches avoid the deep hypothermic circulatory arrest required for full, open surgical repair of the aortic arch. In hybrid repairs, the stent landing zone determines which branch vessels will be covered and therefore need revascularization. This article will review the preprocedure assessment with computed tomography angiography, techniques for revascularization and postprocedure complications. PMID:23621141

  4. Multiple endovascular aortic aneurysm repair graft failures and re-interventions over 15 years

    PubMed Central

    Belchos, Jessica; Wheatcroft, Mark; Moloney, Tony

    2015-01-01

    Re-intervention on abdominal aortic aneurysm treated by endovascular aortic aneurysm repair for complications such as endoleak, graft migration, and graft failure is relatively common. However, re-do endovascular aortic aneurysm repair can be complex, as the failed graft still resides within the vessel. In addition, some re-do endovascular aortic aneurysm repairs call for an advanced custom graft, which can further increase the complexity and technical skill required. We describe a case of a 15-year-old endovascular aortic aneurysm repair originally implanted in a 71-year-old man, followed by three separate complications requiring intervention. We describe important procedural decisions taken into consideration when presented with failure of an older graft. PMID:27489701

  5. Endovascular Aneurysm Repair and Sealing (EVARS): A Useful Adjunct in Treating Challenging Morphology.

    PubMed

    Harrison, Gareth J; Antoniou, George A; Torella, Francesco; McWilliams, Richard G; Fisher, Robert K

    2016-04-01

    An 81-year-old male with previous open abdominal aortic aneurysm repair presented with asymptomatic large pseudoaneurysms at both ends of an open surgical tube graft. Endovascular aneurysm sealing (EVAS) in combination with the iliac limbs of a standard endovascular aneurysm repair (EVAR) successfully excluded both pseudoaneurysms from circulation. We describe the combination of elements of EVAS and EVAR and have termed this endovascular aneurysm repair and sealing (EVARS). EVARS has the advantage of harnessing the benefits of endobag sealing in aortic necks unsuitable for standard EVAR whilst providing the security of accurate stent placement within short common iliac arteries. In conclusion, EVAS may be combined with standard endovascular iliac limbs and is a possible treatment option for pseudoaneurysm following open aneurysm repair. PMID:26493819

  6. Acute and late obstruction of a modified Blalock-Taussig shunt: a two-center experience in different catheter-based methods of treatment.

    PubMed

    Moszura, Tomasz; Zubrzycka, Maria; Michalak, Krzysztof W; Rewers, Bozena; Dryzek, Pawel; Moll, Jacek J; Sysa, Andrzej; Burczynski, Piotr

    2010-05-01

    Modified Blalock-Taussig (B-T) shunt occlusion results in a sudden reduction of pulmonary vascular perfusion, causing dramatic saturation drop and cyanosis which pose a direct hazard to a child's life. The results of percutaneous local r-tpa infusion, balloon angioplasty and additionally stent implantation in obstructed modified B-T shunts were studied to assess their role as an alternative to a re-do surgery. We outline two pediatric centers' experience (period 2004-2008) regarding the effectiveness of various emergency treatment methods for occlusion or critical stenosis of systemic-to-pulmonary arterial shunts in 23 children. Local r-tpa infusion via catheter was performed in 12/23 patients, balloon angioplasty in 22/23 and additionally stent implantation in 3/23 children. Procedures were successful in 22/23 patients (96%), with an increase in arterial saturation [average: 30%; standard deviation (S.D.) 15%; Shapiro-Wilk test; dependent t-test-P<0.01]. Unrestricted contrast flow was achieved in 18 patients, reduced central flow in three and minimal flow in one child. Neither local nor systemic complications occurred. Our experience demonstrates the possibility of successful early shunt recanalization with the use of local thrombolytic therapy combined with the balloon angioplasty. The presence of old fixed thrombus with neointimal hypertrophy in the shunt constitutes an indication for endovascular stent implantation. PMID:20139195

  7. Endovascular Cooling Method for Hypothermia in Injured Swine.

    PubMed

    Arnaud, Françoise; Haque, Ashraful; Solomon, Daniel; Kim, Robert B; Pappas, Georgina; Scultetus, Anke H; Auker, Charles; McCarron, Richard

    2016-06-01

    We evaluated an endovascular cooling method to modulate core temperature in trauma swine models with and without fluid support. Anesthetized swine (N = 80) were uninjured (SHAM) or injured through a bone fracture plus soft tissue injury or an uncontrolled hemorrhage and then subdivided to target body temperatures of 38°C (normothermia) or 33°C (hypothermia) by using a Thermogard endovascular cooling device (Zoll Medical). Temperature regulation began simultaneously at onset of injury (T0). Body temperatures were recorded from a rectal probe (Rec Temp) and from a central pulmonary artery catheter (PA Temp). At T15, swine received 500 mL IV Hextend over 30 minutes or no treatment (NONE) with continued monitoring until 3 hours from injury. Hypothermia was attained in 105 ± 39 minutes, at a cooling rate of -0.061°C ± 0.007°C/min for NONE injury groups. Postinjury Hextend administration resulted in faster cooling (-0.080°C ± 0.006°C/min); target temperature was reached in 83 ± 11 minutes (p < 0.05). During active cooling, body temperature measured by the PA Temp was significantly cooler than the Rec Temp due to the probe's closer proximity to the blood-cooling catheter balloons (p < 0.05). This difference was smaller in SHAM and fluid-supported injury groups (1.1°C ± 0.4°C) versus injured NONE groups (2.1°C ± 0.3°C). Target temperatures were correctly maintained thereafter in all groups. In normothermia groups, there was a small initial transient overshoot to maintain 38°C. Despite the noticeable difference between PA Temp and Rec Temp until target temperature was attained, this endovascular method can safely induce moderate hypothermia in anesthetized swine. However, likely due to their compromised hemodynamic state, cooling in hypovolemic and/or injured patients will be different from those without injury or those that also received fluids. PMID:26918281

  8. Endovascular strategies for treatment of embolizing thoracoabdominal aortic lesions

    PubMed Central

    Jeyabalan, Geetha; Wallace, Justin R.; Chaer, Rabih Antoine; Leers, Steven A.; Marone, Luke Keith; Makaroun, Michel S.

    2014-01-01

    Objective Aortic sources of peripheral and visceral embolization remain challenging to treat. The safety of stent graft coverage continues to be debated. This study reports the outcomes of stent coverage of these complex lesions. Methods Hospital records were retrospectively reviewed for patients undergoing aortic stenting between 2006 and 2013 for visceral and peripheral embolic disease. Renal function, method of coverage, and mortality after stent grafting were reviewed. Results Twenty-five cases of embolizing aortic lesions treated with an endovascular approach were identified. The mean age was 65 ± 13 years (range, 45–87 years), and 64% were female. Sixteen (64%) patients presented with peripheral embolic events, six with concomitant renal embolization. Five patients presented with abdominal or flank pain, and two were discovered incidentally. Three patients had undergone an endovascular procedure for other indications within the preceding 6 months of presentation. Nineteen patients had existing chronic kidney disease (stage II or higher), but only three had stage IV disease. Of the eight patients tested, four had a diagnosed hypercoagulable state. Eight of the patients had lesions identified in multiple aortic segments, and aortic aneurysm disease was present in 24%. Coverage of both abdominal and thoracic sources occurred in eight patients, whereas 17 had only one segment covered. Minimal intraluminal catheter and wire manipulation was paired with the use of intravascular ultrasound in an effort to reduce embolization and contrast use. Intravascular ultrasound was used in the majority of cases and transesophageal echo in 28% of patients. Two patients with stage IV kidney disease became dialysis-dependent within 3 months of the procedure. No other patients had an increase in their postoperative or predischarge serum creatinine levels. No embolic events were precipitated during the procedure, nor were there any recurrent embolic events detected on follow

  9. Popliteal Artery Aneurysm Repair in the Endovascular Era

    PubMed Central

    Ronchey, Sonia; Pecoraro, Felice; Alberti, Vittorio; Serrao, Eugenia; Orrico, Matteo; Lachat, Mario; Mangialardi, Nicola

    2015-01-01

    Abstract To compare outcomes of popliteal artery aneurysm (PAA) repair by endovascular treatment, great saphenous vein (GSV) bypass, and prosthetic bypass. Single center retrospective analysis of patients presenting PAA from 2000 to 2013. Patients were divided into endovascular treatment (group A); GSV bypass (group B); and prosthetic graft bypass (group C). Outcomes were technical success, perioperative mortality, and morbidity. Survival, primary and secondary patency, and freedom from reintervention rate were estimated. Differences in ankle-brachial index (ABI), in-hospital length of stay (InH-Los), red blood cell (RBC) transfusion, and limb loss were reported. Mean follow-up was 49 (median: 35; 1–145; SD 42) months. Sixty-seven patients were included; 25 in group A, 28 in group B, and 14 in group C. PAA was symptomatic in 23 (34%) cases. Technical success was 100%. No perioperative death occurred. Three (4.5%) perioperative complications were reported with no significant difference between groups (P = 0.866). Five-years estimated survival was 78%. Estimated 5-years primary patency for groups A, B, and C was 71%, 81%, and 69%, respectively (P = 0.19). Estimated 5-years secondary patency for groups A, B, and C was 88%, 85%, and 84% (P = 0.85). Estimated 5-years freedom from reintervention for groups A, B, and C was 62%, 84%, and 70%, respectively (P = 0.16). A significant difference between preoperative ABI versus postoperative ABI was observed (P = 0.001). InH-LoS was significantly shorter in group A (P < 0.001). RBC transfusions were required significantly less in group A when compared to group C (P = 0.045). Overall limb salvage was achieved in all but 1 patient. PAA repair has good early and long-term outcomes with different treatment options. Endovascular treatment was not inferior to surgical repair with a reduced InH-LoS and RBC transfusion. It can be successfully employed even in nonelective setting. A randomized controlled

  10. Endovascular stent graft for traumatic splenic vein aneurysm via percutaneous transsplenic access

    PubMed Central

    Kwon, Oh Sang; Kim, Joong Suck; Kim, Ji Dae

    2016-01-01

    Traumatic splenic vein aneurysm (SVA) is an extremely rare entity. Traditionally, treatment varied from noninvasive followup to aneurysm excision with splenectomy. However, there has been no prior report of traumatic SVA treated with endovascular stent graft for SVA via percutaneous transsplenic access. Therefore, we report the case of a 56-year-old man successfully treated with endovascular stent graft for traumatic SVA via percutaneous transsplenic access. PMID:27433466

  11. Epithelioid Angiosarcoma With Metastatic Disease After Endovascular Therapy of Abdominal Aortic Aneurysm

    SciTech Connect

    Schmehl, Joerg; Scharpf, Marcus; Brechtel, Klaus; Kalender, Guenay; Heller, Stephan; Claussen, Claus D.; Lescan, Mario

    2012-02-15

    Malignancies of the aortic wall represent a rare condition, and only a few reports have covered cases of sarcomas arising at the site of a prosthesis made of Dacron. A coincidence with endovascular repair has only been reported in one case to date. We report a patient with epithelioid angiosarcoma and metastatic disease, which was found in an aneurysmal sac after endovascular aortic repair for abdominal aortic aneurysm.

  12. Percutaneous endovascular management of atherosclerotic axillary artery stenosis: Report of 2 cases and review of literature

    PubMed Central

    Vijayvergiya, Rajesh; Yadav, Mukesh; Grover, Anil

    2011-01-01

    With recent advancement in percutaneous endovascular management, most atherosclerotic peripheral arterial diseases are amenable for intervention. However, there is limited published literature about atherosclerotic axillary artery involvement and its endovascular management. We report two cases of atherosclerotic axillary artery stenosis, which were successfully managed with stent angioplasty using self expanding nitinol stents. The associated coronary artery disease was treated by percutaneous angioplasty and stenting. The long term follow-up revealed patent axillary stents in both cases. PMID:21666817

  13. Logistical and financial obstacles for endovascular therapy of acute stroke implementation.

    PubMed

    Schellinger, Peter D; Köhrmann, Martin; Nogueira, Raul G

    2016-07-01

    After publication of the recent positive randomized clinical endovascular trials, several questions and obstacles for wide spread implementation remain. We address specific issues namely efficacy, safety, logistics, timing, sedation, numbers, imaging, manpower, centers, geographics, and economical aspects of endovascular therapy. As we move forward, a high degree of collaboration will be crucial to implement a therapy with established overwhelming treatment efficacy for severe acute stroke patients. PMID:27016510

  14. Surgical Repair of Retrograde Type A Aortic Dissection after Thoracic Endovascular Aortic Repair

    PubMed Central

    Kim, Chang-Young; Kim, Yeon Soo; Ryoo, Ji Yoon

    2014-01-01

    It is expected that the stent graft will become an alternative method for treating aortic diseases or reducing the extent of surgery; therefore, thoracic endovascular aortic repair has widened its indications. However, it can have rare but serious complications such as paraplegia and retrograde type A aortic dissection. Here, we report a surgical repair of retrograde type A aortic dissection that was performed after thoracic endovascular aortic repair. PMID:24570865

  15. Endovascular stent graft repair for thoracic aortic aneurysms: the history and the present in Japan.

    PubMed

    Kawaguchi, Satoshi; Shimizu, Hideyuki; Yoshitake, Akihiro; Shimazaki, Taro; Iwahashi, Toru; Ogino, Hitoshi; Ishimaru, Shin; Shigematsu, Hiroshi; Yozu, Ryohei

    2013-01-01

    Stent-grafts for endovascular repair of thoracic aortic aneurysms have been commercially available for more than ten years in the West, whereas, in Japan, a manufactured stent-graft was not approved for the use until March 2008. Nevertheless, endovascular thoracic intervention began to be performed in Japan in the early 1990s, with homemade devices used in most cases. Many researchers have continued to develop their homemade devices. We have participated in joint design and assessment efforts with a stent-graft manufacturer, focusing primarily on fenestrated stent-grafts used in repairs at the distal arch, a site especially prone to aneurysm. In March 2008, TAG (W.L. Gore & Associates, Inc., Flagstaff, Arizona, USA) was approved as a stent graft for the thoracic area first in Japan, which was major turning point in treatment for thoracic aortic aneurysms. Subsequently, TALENT (Medtronic, Inc., Minneapolis, Minnesota, USA) was approved in May 2009, and TX2 (COOK MEDICAL Inc., Bloomington, Indiana, USA) in March 2011. Valiant as an improved version of TALENT was approved in November 2011, and TX2 Proform as an improved version of TX2 began to be supplied in October 2012. These stent grafts are excellent devices that showed good results in Western countries, and marked effectiveness can be expected by making the most of the characteristics of each device. A clinical trial in Japan on Najuta (tentative name) (Kawasumi Labo., Inc., Tokyo, Japan) as a line-up of fenestrated stent grafts that can be applied to distal arch aneurysms showing a high incidence, and allow maintenance of blood flow to the arch vessel was initiated. This trial was completed, and Najuta has just been approved in January of 2013 in Japan, and further development is expected. In the U.S., great efforts have recently been made to develop and manufacture excellent stent grafts for thoracic aneurysms, and rapid progress has been achieved. In particular, in the area of the aortic arch, in which we

  16. Deformable Surface Model for the Evaluation of Abdominal Aortic Aneurysms Treated with an Endovascular Sealing System.

    PubMed

    Casciaro, Mariano E; El-Batti, Salma; Chironi, Gilles; Simon, Alain; Mousseaux, Elie; Armentano, Ricardo L; Alsac, Jean-Marc; Craiem, Damian

    2016-05-01

    Rupture of abdominal aortic aneurysms (AAA) is responsible for 1-3% of all deaths among the elderly population in developed countries. A novel endograft proposes an endovascular aneurysm sealing (EVAS) system that isolates the aneurysm wall from blood flow using a polymer-filled endobag that surrounds two balloon-expandable stents. The volume of injected polymer is determined by monitoring the endobag pressure but the final AAA expansion remains unknown. We conceived and developed a fully deformable surface model for the comparison of pre-operative sac lumen size and final endobag size (measured using a follow-up scan) with the volume of injected polymer. Computed tomography images were acquired for eight patients. Aneurysms were manually and automatically segmented twice by the same observer. The injected polymer volume resulted 9% higher than the aneurysm pre-operative lumen size (p < 0.05), and 11% lower than the final follow-up endobag volume (p < 0.01). The automated method required minimal user interaction; it was fast and used a single set of parameters for all subjects. Intra-observer and manual vs. automated variability of measured volumes were 0.35 ± 2.11 and 0.07 ± 3.04 mL, respectively. Deformable surface models were used to quantify AAA size and showed that EVAS system devices tended to expand the sac lumen size. PMID:26350505

  17. Endovascular Management of Visceral Artery Pseudoaneurysms: Transcatheter Coil Embolization Using the Isolation Technique

    SciTech Connect

    Ikeda, Osamu Nakasone, Yutaka; Tamura, Yoshitaka; Yamashita, Yasuyuki

    2010-12-15

    PurposeTo describe our experiences with treatment of visceral artery pseudoaneurysms (VAPA) by transcatheter coil embolization using an isolation technique and to propose indications for treating VAPA with this method.Materials and MethodsWe treated 37 patients with VAPA endovascularly: There were 15 pancreaticoduodenal arcade, 10 hepatic, 5 renal, 3 splenic, and 1 each left gastric, gastroepiploic, adrenal, and superior mesenteric artery pseudoaneurysms. Preprocedure computed tomography (CT) and/or angiographic studies confirmed the presence of VAPA in all 37 patients. Using the isolation technique, we embolized vessels at sites distal and proximal to the pseudoaneurysm.ResultsTranscatheter coil embolization with the isolation technique was technically successful in 33 (89%) of 37 patients, and angiogram confirmed the complete disappearance of the VAPA in 32 patients. No major complications occurred during the procedures. In a patient with a pancreaticoduodenal arcade artery pseudoaneurysm, we were unable to control hemorrhage. In 30 of 32 patients who recovered after transcatheter coil embolization using the isolation technique, follow-up CT scan showed no flow in VAPA; they survived without rebleeding. Two of the 32 patients (6%) with confirmed complete disappearance of VAPA on angiogram and CT scan obtained the day after the procedure manifested rebleeding during follow-up.ConclusionTranscatheter coil embolization using the isolation technique is an effective alternative treatment in patients with VAPA. In combination with coil embolization, the isolation technique is particularly useful in patients whose pseudoaneurysms present surgical difficulties.

  18. A numerical framework to investigate hemodynamics during endovascular mechanical recanalization in acute stroke.

    PubMed

    Neidlin, Michael; Büsen, Martin; Brockmann, Carolin; Wiesmann, Martin; Sonntag, Simon J; Steinseifer, Ulrich; Kaufmann, Tim A S

    2016-04-01

    Ischemic stroke, caused by embolism of cerebral vessels, inflicts high morbidity and mortality. Endovascular aspiration of the blood clot is an interventional technique for the recanalization of the occluded arteries. However, the hemodynamics in the Circle of Willis (CoW) are not completely understood, which results in medical misjudgment and complications during surgeries. In this study we establish a multiscale description of cerebral hemodynamics during aspiration thrombectomy. First, the CoW is modeled as a 1D pipe network on the basis of computed tomography angiography (CTA) scans. Afterwards, a vascular occlusion is placed in the middle cerebral artery and the relevant section of the CoW is transferred to a 3D computational fluid dynamic (CFD) domain. A suction catheter in different positions is included in the CFD simulations. The boundary conditions of the 3D domain are taken from the 1D domain to ensure system coupling. A Eulerian-Eulerian multiphase simulation describes the process of thrombus aspiration. The physiological blood flow in the 1D and 3D domains is validated with literature data. Further on, it is proved that domain reduction and pressure coupling at the boundaries are an appropriate method to reduce computational costs. Future work will apply the developed framework to various clinical questions. PMID:26420012

  19. Intrasellar Iatrogenic Carotid Pseudoaneurysm: Endovascular Treatment with a Polytetrafluoroethylene-Covered S tent

    SciTech Connect

    Vanninen, R. L. Manninen, H. I.; Rinne, J.

    2003-06-15

    This case illustrates successful treatment of a large postoperative intrasellar pseudoaneurysm with a polytetrafluoroethylene (PTFE)-covered stent. The advantages and potential disadvantages of this novel method of treatment are discussed. A previously healthy 59-year-old man underwent transsphenoidal operative treatment for hypophyseal macroadenoma,complicated by bleeding. On the 17{sup th} postoperative day the patient had profuse arterial bleeding from his nose requiring posterior tamponade. Subsequent angiography of the left internal carotid artery(ICA) revealed a large pseudoaneurysm located intrasellarly, with the orifice in the anteromedial wall in the ophthalmic segment of the ICA.Surgical treatment of the pseudoaneurysm was considered very risky. A12-mm PTFE-covered stent (JoMed, Ulestraten, Netherlands), manually compressed on a PTCA-balloon (Maxxum 4.5/13 mm, Boston Scientific,Ireland) was endovascularly delivered covering the orifice of the pseudoaneurysm. Control angiography immediately after the intervention and one year later revealed no flow into the pseudoaneurysm and the ICA was fully patent. In conclusion, deployment of a PTFE-covered stent proved to be feasible and successful in the treatment of an intrasellariatrogenic ICA pseudoaneurysm. Adequate anticoagulative treatment after the procedure is essential to prevent thrombotic complications.

  20. Constraining OCT with Knowledge of Device Design Enables High Accuracy Hemodynamic Assessment of Endovascular Implants

    PubMed Central

    Brown, Jonathan; Lopes, Augusto C.; Kunio, Mie; Kolachalama, Vijaya B.; Edelman, Elazer R.

    2016-01-01

    Background Stacking cross-sectional intravascular images permits three-dimensional rendering of endovascular implants, yet introduces between-frame uncertainties that limit characterization of device placement and the hemodynamic microenvironment. In a porcine coronary stent model, we demonstrate enhanced OCT reconstruction with preservation of between-frame features through fusion with angiography and a priori knowledge of stent design. Methods and Results Strut positions were extracted from sequential OCT frames. Reconstruction with standard interpolation generated discontinuous stent structures. By computationally constraining interpolation to known stent skeletons fitted to 3D ‘clouds’ of OCT-Angio-derived struts, implant anatomy was resolved, accurately rendering features from implant diameter and curvature (n = 1 vessels, r2 = 0.91, 0.90, respectively) to individual strut-wall configurations (average displacement error ~15 μm). This framework facilitated hemodynamic simulation (n = 1 vessel), showing the critical importance of accurate anatomic rendering in characterizing both quantitative and basic qualitative flow patterns. Discontinuities with standard approaches systematically introduced noise and bias, poorly capturing regional flow effects. In contrast, the enhanced method preserved multi-scale (local strut to regional stent) flow interactions, demonstrating the impact of regional contexts in defining the hemodynamic consequence of local deployment errors. Conclusion Fusion of planar angiography and knowledge of device design permits enhanced OCT image analysis of in situ tissue-device interactions. Given emerging interests in simulation-derived hemodynamic assessment as surrogate measures of biological risk, such fused modalities offer a new window into patient-specific implant environments. PMID:26906566

  1. The role of simulation in the development of endovascular surgical skills.

    PubMed

    Nesbitt, Craig Iain; Birdi, Nikhil; Mafeld, Sebastian; Stansby, Gerrard

    2016-02-01

    Endovascular trainees in the National Health Service still largely rely on the apprentice-apprenticeship model from the late 19th century. As the scope for endovascular therapy increases, due to the rapid innovation, evolution and refinement of technology, so too do patients' therapeutic options. This climate has also opened the door for more novel training adjuncts, to address the gaps that exist in our current endovascular training curriculum. The aim of this paper is to present a succinct overview of endovascular simulation, synthesizing the trials and research behind this rapidly evolving training as well as highlighting areas where further research is required. The authors searched MEDLINE and EMBASE for relevant manuscripts on all aspects of endovascular simulation training. A comprehensive Google search was also undertaken to look for any relevant information on endovascular training courses available and any unpublished work that had been presented at relevant scientific meetings. Papers were categorized into the four models: synthetic, animal, virtual reality and human cadaver, and separate searches for evidence of skill transfer were also undertaken. Authors of novel research projects were contacted for further details of unpublished work and permission granted to report such findings in this manuscript. PMID:26797930

  2. The Growth Rate of Early DWI Lesions is Highly Variable and Associated with Penumbral Salvage and Clinical Outcomes Following Endovascular Reperfusion

    PubMed Central

    Wheeler, Hayley M; Mlynash, Michael; Inoue, Manabu; Tipirnini, Aaryani; Liggins, John; Bammer, Roland; Lansberg, Maarten G; Kemp, Stephanie; Zaharchuk, Greg; Straka, Matus; Albers, Gregory W

    2014-01-01

    Importance The degree of variability in the rate of early DWI expansion in acute stroke has not been well characterized. Objective We hypothesized that patients with slowly expanding DWI lesions would have more penumbral salvage and better clinical outcomes following endovascular reperfusion than patients with rapidly expanding DWI lesions. Methods In the first part of this substudy of DEFUSE 2, growth curves were constructed for patients with >90% reperfusion and <10% reperfusion. Next, the initial growth rate was determined in all patients with a clearly established time of symptom onset, assuming a lesion volume of 0ml just prior to symptom onset. Patients who achieved reperfusion (>50% reduction in PWI after endovascular therapy), were categorized into tertiles according to their initial DWI growth rates. For each tertile, penumbral salvage (comparison of final volume to the volume of PWI (Tmax > 6 sec)/ DWI mismatch prior to endovascular therapy), favorable clinical response (NIHSS improvement of ≥8 points or 0-1 at 30 days), and good functional outcome (90 day modified Rankin score of ≤ 2) were calculated. A multivariate model assessed whether infarct growth rates were an independent predictor of clinical outcomes. Results 65 patients were eligible for this study; the median initial growth rate was 3.1 ml/hr (IQR 0.7-10.7). Target mismatch patients (n=42) had initial growth rates that were significantly slower than the growth rates in Malignant profile (n=9) patients p < 0.001). In patients who achieved reperfusion (n=38), slower early DWI growth rates were associated with better clinical outcomes (p<0.05) and a trend toward more penumbral salvage (n=31, p=0.103). A multivariate model demonstrated that initial DWI growth rate was an independent predictor of achieving a 90 day modified Rankin score of ≤ 2. Conclusions The growth rate of early DWI lesions in acute stroke patients is highly variable; Malignant profile patients have higher growth rates than

  3. Sedimentation field-flow fractionation for characterization of citric acid-modified Hβ zeolite particles: Effect of particle dispersion and carrier composition.

    PubMed

    Dou, Haiyang; Bai, Guoyi; Ding, Liang; Li, Yueqiu; Lee, Seungho

    2015-11-27

    In this study, sedimentation field-flow fractionation (SdFFF) was, for the first time, applied for determination of size distribution of Hβ zeolite particles modified by citric acid (CA-Hβ). Effects of the particle dispersion and the carrier liquid composition (type of dispersing reagent (surfactant) and salt added in the carrier liquid, ionic strength, and pH) on SdFFF elution behavior of CA-Hβ zeolite particles were systematically investigated. Also the SdFFF separation efficiency of the particles was discussed in terms of the forces such as van der Waals, hydrophobic, and induced-dipole interactions. Results reveal that the type of salt and pH of the carrier liquid significantly affect the SdFFF separation efficiency of the zeolite particles. It was found that addition of a salt (NaN3) into the carrier liquid affects the characteristic of the SdFFF channel surface. It was found that the use of an acidic medium (pH 3.2) leads to a particle-channel interaction, while the use of a basic medium (pH 10.6) promotes an inter-particle hydrophobic interaction. Result from SdFFF was compared with those from scanning electron microscopy (SEM) and dynamic light scattering (DLS). It seems that, once the experimental conditions are optimized, SdFFF becomes a valuable tool for size characterization of the zeolite particles. PMID:26493474

  4. Comparative research on phosphorus removal by pilot-scale vertical flow constructed wetlands using steel slag and modified steel slag as substrates.

    PubMed

    Yun, Yupan; Zhou, Xiaoqin; Li, Zifu; Uddin, Sayed Mohammad Nazim; Bai, Xiaofeng

    2015-01-01

    This research mainly focused on the phosphorus removal performance of pilot-scale vertical flow constructed wetlands with steel slag (SS) and modified steel slag (MSS). First, bench-scale experiments were conducted to evaluate the phosphorus adsorption capacity. Results showed that the Langmuir model could better describe the adsorption characteristics of the two materials; the maximum adsorption of MSS reached 12.7 mg/g, increasing by 34% compared to SS (9.5 mg/g). Moreover, pilot-scale constructed wetlands with SS and MSS were set up outdoors. Then, the influence of hydraulic retention time (HRT) and phosphorus concentration in phosphorus removal for two wetlands were investigated. Results revealed that better performance of the two systems could be achieved with an HRT of 2 d and phosphorus concentration in the range of 3-4.5 mg/L; the system with MSS had a better removal efficiency than the one with SS in the same control operation. Finally, the study implied that MSS could be used as a promising substrate for wetlands to treat wastewater with a high phosphorus concentration. However, considering energy consumption, SS could be regarded as a better alternative for substrate when treating sewage with a low phosphorus concentration. PMID:25860701

  5. A proposal to induce pulsating aurora by injecting ions from a rocket at the magnetic conjugate ionosphere to modify the flowing cyclotron maser

    NASA Astrophysics Data System (ADS)

    Chernouss, S.; Mogilevsky, M.; Trakhtengerts, V.; Deehr, C.; Stenbaek-Nielsen, H.

    2005-08-01

    There is experimental evidence for the artificial induction of Flowing Cyclotron Maser (FCM) by reflection coefficient modification. It is the close correlation of auroral pulsations and auroral VLF emissions that is the experimental basis of the theory. We review experiments with ionospheric barium vapor releases, when auroral pulsations were apparently triggered. This effect has been observed during a Ba-release rocket campaign in Alaska. In this experiment, the stimulation of auroral pulsations generated by a Ba-release during special auroral activity was clearly observed. Similar results were obtained during a Russian rocket campaign to release barium vapor in the ionosphere over the North Atlantic. It seems that changing the reflection coefficient is a main reason for the generation of auroral pulsations in both Ba release experiments. Thus, the apparent dependence of the cyclotron instability increment on the reflection coefficient of the FCM foot point parameters give us the possibility of modifying FCM by creating ion clouds in the ionosphere. It is proposed as a part of the RESONANCE satellite project to create an artificial ion cloud at the magnetic conjugate point of the satellite from Poker Flat Research Range during the satellite passage over Alaska. The details of the proposed experiment and the necessary geophysical situation are still under discussion.

  6. Experimental Research on Balloon-expandable Endovascular Stent Expansion.

    PubMed

    Wang, Yuexuan; Yi, Hong; Ni, Zhonghua

    2005-01-01

    The application background and experimental research overview of medical endovascular stent are presented. Based on the analytical comparison of the current research achievements, the life cycle of medical vascular stent, which is composed of three phases of mounting, deployment and long-term in vivo service, is pointed out and the characteristics of stent expansion process in the life cycle are emphasized on. The experimental scheme of in vitro stent expansion based on the machine vision technology in LabVIEW is presented. The selected component devices and measurement program for experiment are expatiated. A special drug-loading stent was expanded on the assembled platform of selected equipments and experimental results are analyzed. The experimental scheme presented in the paper provides powerful experimental support for the computer simulation of stent expansion process by the finite element analysis. PMID:17282686

  7. Management of Severe Hemoptysis from Pulmonary Aspergilloma Using Endovascular Embolization

    SciTech Connect

    Corr, Peter

    2006-10-15

    Purpose. To determine the effectiveness of endovascular embolization as a temporizing measure in the management of severe hemoptysis caused by intracavitary pulmonary aspergilloma. Methods. Patients presenting with hemoptysis, estimated to be more than 300 ml in the preceding 24 hr, in whom a radiological diagnosis of pulmonary aspergilloma was made on chest radiographs and/or computed tomography of the chest were subjected to bronchial and systemic arteriography and embolization using triacryl microspheres. Results. Twelve patients with upper lobe intracavitary aspergillomas were managed with embolization. In 11 patients hemoptysis stopped within 24 hr and with no recurrence over the next 4 weeks. In 1 patient hemoptysis persisted and an upper lobe lobectomy was performed. Conclusion. Embolization of bronchial and systemic arteries is an effective method for treating acute severe hemoptysis from intracavitary aspergillomas, allowing the patient time to recover for definitive surgical management.

  8. Anesthetic considerations for endovascular abdominal aortic aneurysm repair

    PubMed Central

    Kothandan, Harikrishnan; Haw Chieh, Geoffrey Liew; Khan, Shariq Ali; Karthekeyan, Ranjith Baskar; Sharad, Shah Shitalkumar

    2016-01-01

    Aneurysm is defined as a localized and permanent dilatation with an increase in normal diameter by more than 50%. It is more common in males and can affect up to 8% of elderly men. Smoking is the greatest risk factor for abdominal aortic aneurysm (AAA) and other risk factors include hypertension, hyperlipidemia, family history of aneurysms, inflammatory vasculitis, and trauma. Endovascular Aneurysm Repair [EVAR] is a common procedure performed for AAA, because of its minimal invasiveness as compared with open surgical repair. Patients undergoing EVAR have a greater incidence of major co-morbidities and should undergo comprehensive preoperative assessment and optimization within the multidisciplinary settings. In majority of cases, EVAR is extremely well-tolerated. The aim of this article is to outline the Anesthetic considerations related to EVAR. PMID:26750684

  9. Thrombus Volume Change Visualization after Endovascular Abdominal Aortic Aneurysm Repair

    NASA Astrophysics Data System (ADS)

    Maiora, Josu; García, Guillermo; Macía, Iván; Legarreta, Jon Haitz; Boto, Fernando; Paloc, Céline; Graña, Manuel; Abuín, Javier Sanchez

    A surgical technique currently used in the treatment of Abdominal Aortic Aneurysms (AAA) is the Endovascular Aneurysm Repair (EVAR). This minimally invasive procedure involves inserting a prosthesis in the aortic vessel that excludes the aneurysm from the bloodstream. The stent, once in place acts as a false lumen for the blood current to travel down, and not into the surrounding aneurysm sac. This procedure, therefore, immediately takes the pressure off the aneurysm, which thromboses itself after some time. Nevertheless, in a long term perspective, different complications such as prosthesis displacement or bloodstream leaks into or from the aneurysmatic bulge (endoleaks) could appear causing a pressure elevation and, as a result, increasing the danger of rupture. The purpose of this work is to explore the application of image registration techniques to the visual detection of changes in the thrombus in order to assess the evolution of the aneurysm. Prior to registration, both the lumen and the thrombus are segmented

  10. Endovascular management of IVC syndrome after IVC filter placement.

    PubMed

    Marmagkiolis, Konstantinos; Lendel, Vasili; Cilingiroglu, Mehmet

    2015-09-01

    Approximately 60,000-100,000 Americans die from deep venous thrombosis or pulmonary embolism annually, while the overall estimate of individuals affected is 30,000-600,000. Inferior vena cava (IVC) filter placement has emerged as a break-through endovascular technique which has gained increasing acceptance and has probably saved thousands of lives by preventing fatal thromboembolic events. However, in the absence of a national IVC filter registry an accurate estimate of device complications is currently unavailable. We present a case of symptomatic IVC syndrome due to IVC interruption in a patient with a non-retrievable IVC filter. This patient was initially managed with balloon angioplasty and mechanical thrombectomy with suboptimal results and subsequently with stent placement through the IVC filter. PMID:26298105

  11. [Endovascular stent implantation as a treatment for iliac artery disease].

    PubMed

    Tetteroo, E; van Engelen, A D; van der Graaf, Y; Mali, W P

    2000-01-22

    A stent is an endovascular prosthesis that may be used in the treatment of intermittent claudication caused by lesions of the A. iliaca communis and the A. iliaca externa in which earlier balloon dilatation has proved insufficiently effective. The expansion is caused by inflation of an angioplasty balloon (plastic remodelling: Palmaz stent) or by self-expansion due to elastic transformation as in the Wail stent or to thermic memory metal, as in the Memotherm stent. Evaluation of the literature shows that stent placement is a safe method of treatment. The proportion of initial technical success appears to be higher than that of balloon angioplasty, especially in the treatment of total occlusions. The haemodynamic situation immediately after treatment also appears to be better in case of stent placement. Long-term comparison of the clinical efficacy is not well possible because the published studies differ with regard to patient population, definition of indication and criteria of success. PMID:10668541

  12. Endovascular infection with Salmonella group C – a case report

    PubMed Central

    Arbune, Manuela; Ciobotaru, Roxana; Voinescu, Doina Carina

    2015-01-01

    Introduction The risk of secondary endovascular infections after bacteremia with Salmonella spp. is augmented by preexisting atherosclerotic arterial lesions. Over the age of 50, the incidence varies between 25 and 35%. Case report A 57-year-old male, smoker, alcohol user, in poor social condition, was hospitalized for fever, malaise, left leg persistent thrombophlebitis, coxofemoral and back pain. His medical history was significant for recent sepsis with Salmonella group C, and a recent diagnosis of hepatitis C. During the antibiotic treatment, he complained of a left inguinal tumor, corresponding to a paravertebral image along the left psoas muscle identified by abdominal computed tomography. A paravertebral hematoma and an aneurysm of the left aortoiliac junction were repaired by surgery. The culture of the aneurysm was positive for Salmonella group C. Conclusion The differential diagnosis of lower limb persistent thrombophlebitis should consider the compression by abdominal aneurysm, consequent to a vascular complication from bacteremia with Salmonella spp. PMID:26405678

  13. Endovascular repair of mitroaortic intervalvular fibrosa aneurysm after bentall surgery.

    PubMed

    Vola, Marco; Gerbay, Antoine; Campisi, Salvatore; Duprey, Ambroise; Heller, Fabien; Patoir, Arnaud; Albertini, Jean Noel; Fuzellier, Jean Francois; Isaaz, Karl; Favre, Jean Pierre

    2015-02-01

    We report the first case of a successful transapical transcatheter treatment of a giant pseudoaneurysm originating from a rupture of the mitroaortic fibrosa that occurred 3 months after a Bentall procedure in a 81-year-old male patient. Because of the age of the patient and the location of the leak at the mitroaortic fibrosa, the risk of a conventional ascending aorta reoperation was considered too high, and a transcatheter approach was chosen. A transapical puncture was performed with a left minithoracotomy followed by a catheterization of the pseudoaneurysm neck and an 8-mm Amplatzer (St. Jude Medical, Saint Paul, MN, USA) device was delivered, resulting in a successful complete endovascular exclusion of the pseudo-aneurysmal sac. PMID:25639415

  14. Imaging findings and endovascular management of iatrogenic hepatic arterial injuries.

    PubMed

    Güneyli, Serkan; Gök, Mustafa; Çınar, Celal; Bozkaya, Halil; Korkmaz, Mehmet; Parıldar, Mustafa; Oran, İsmail

    2015-01-01

    Iatrogenic hepatic arterial injuries (IHAIs) include pseudoaneurysm, extravasation, arteriovenous fistula, arteriobiliary fistula, and dissection. IHAIs are usually demonstrated following percutaneous transhepatic biliary drainage, percutaneous liver biopsy, liver surgery, chemoembolization, radioembolization, and endoscopic retrograde cholangiopancreatography. The latency period between the intervention and diagnosis varies. The most common symptom is hemorrhage, and the most common lesion is pseudoaneurysm. Computed tomography angiography (CTA) is mostly performed prior to angiography, and IHAIs are demonstrated on CTA in most of the patients. Patients with IHAI are mostly treated by coils, but some patients may be treated by liquid embolic materials or stent-grafts. CTA can also be used in the follow-up period. Endovascular treatment is a safe and minimally invasive treatment option with high success rates. PMID:26359873

  15. Iatrogenic dissection of the descending aorta: Conservative or endovascular treatment?

    PubMed

    Baikoussis, Nikolaos G; Argiriou, Michalis; Kratimenos, Theodoros; Karameri, Vasiliki; Dedeilias, Panagiotis

    2016-01-01

    Transcatheter aortic valve implantation (TAVI) is without any doubt a standard technique and the treatment of choice of severe aortic valve stenosis (AVS) in very high-operative risk patients. However, a number of complications may occur and has been described. Improper valve position, valve migration, paravalvular regurgitation, conduction disturbances, stroke and aortic dissection have been succeeded despite the perfection of the technique. For anyone of the complications above described, a solution may be invented. We present an interesting case of an 81-year-old woman with severe AVS treated through TAVI due to very high operative risk. This female, 12 days later presented with thoracic pain and shortness of breath and through the computed tomography of the chest performed was diagnosed a dissection of the descending aorta. She successfully underwent on thoracic endovascular aortic repair. In this report, we refer the bibliographic data and we discuss the treatment options in these cases. PMID:27397470

  16. Endovascular treatment of carotid cavernous sinus fistula: A systematic review

    PubMed Central

    Korkmazer, Bora; Kocak, Burak; Tureci, Ercan; Islak, Civan; Kocer, Naci; Kizilkilic, Osman

    2013-01-01

    Carotid cavernous sinus fistulas are abnormal communications between the carotid system and the cavernous sinus. Several classification schemes have described carotid cavernous sinus fistulas according to etiology, hemodynamic features, or the angiographic arterial architecture. Increased pressure within the cavernous sinus appears to be the main factor in pathophysiology. The clinical features are related to size, exact location, and duration of the fistula, adequacy and route of venous drainage and the presence of arterial/venous collaterals. Noninvasive imaging (computed tomography, magnetic resonance, computed tomography angiography, magnetic resonance angiography, Doppler) is often used in the initial work-up of a possible carotid cavernous sinus fistulas. Cerebral angiography is the gold standard for the definitive diagnosis, classification, and planning of treatment for these lesions. The endovascular approach has evolved as the mainstay therapy for definitive treatment in situations including clinical emergencies. Conservative treatment, surgery and radiosurgery constitute other management options for these lesions. PMID:23671750

  17. Surgical Management of Recurrent Tracheocarotid Fistula following Endovascular Stent Placement

    PubMed Central

    Steitz, Jeffrey T.; Cappello, Zachary J.; Katrib, Ziad; Tennant, Paul A.

    2015-01-01

    We report the case of a 25-year-old woman who developed a tracheocarotid fistula secondary to an infected endovascular stent placed in the right carotid artery after the patient experienced hemorrhage on her first tracheostomy change. The patient originally had the tracheostomy placed at an outside hospital in September 2014, due to prolonged intubation after a motor vehicle accident. The patient presented to the otolaryngology service with an acute tracheal hemorrhage. This necessitated a neck exploration, median sternotomy, right carotid stent removal with subclavian to carotid bypass, and sternocleidomastoid flap reconstruction. This paper addresses the epidemiology and anatomy of a tracheocarotid fistula and discusses methods to treat such a complication. PMID:26693370

  18. Design and biocompatibility of endovascular aneurysm filling devices

    PubMed Central

    Rodriguez, Jennifer N.; Hwang, Wonjun; Horn, John; Landsman, Todd L.; Boyle, Anthony; Wierzbicki, Mark A.; Hasan, Sayyeda M.; Follmer, Douglas; Bryant, Jesse; Small, Ward; Maitland, Duncan J.

    2014-01-01

    The rupture of an intracranial aneurysm, which can result in severe mental disabilities or death, affects approximately 30,000 people in the United States annually. The traditional surgical method of treating these arterial malformations involves a full craniotomy procedure, wherein a clip is placed around the aneurysm neck. In recent decades, research and device development have focused on new endovascular treatment methods to occlude the aneurysm void space. These methods, some of which are currently in clinical use, utilize metal, polymeric, or hybrid devices delivered via catheter to the aneurysm site. In this review, we present several such devices, including those that have been approved for clinical use, and some that are currently in development. We present several design requirements for a successful aneurysm filling device and discuss the success or failure of current and past technologies. We also present novel polymeric based aneurysm filling methods that are currently being tested in animal models that could result in superior healing. PMID:25044644

  19. Endovascular Treatment of Proximal Anastomotic Aneurysms After Aortic Prosthetic Reconstruction

    SciTech Connect

    Tiesenhausen, Kurt; Hausegger, Klaus A.; Tauss, Josef; Amann, Wilfried; Koch, Guenter

    2001-01-15

    Purpose: To describe the efficacy and value of endovascular stent-grafts for the treatment of aortic anastomotic pseudoaneurysms.Methods: Three patients with proximal aortic anastomotic pseudoaneurysms 8-15 years after prosthetic reconstruction were treated by transfemoral stent-graft implantation. In two patients the pseudoaneurysms were excluded by Talent prostheses [tube graft (n = 1), bifurcated graft (n = 1)]. In one patient an uni iliac Zenith stent-graft was implanted and an extra-anatomic crossover bypass for revascularization of the contralateral lower extremity was performed.Results: All procedures were successful with primary exclusion of the pseudoaneurysms. During the follow-up (mean 16 months) one endoleak occurred due to migration of the tube stent-graft. The endoleak was sealed successfully by implanting an additional bifurcated stent-graft.Conclusion: Stent-graft exclusion of aortic pseudoaneurysms offers a minimally invasive and safe alternative to open surgical reconstruction.

  20. Endovascular treatment of proximal arsastomotic aneurysms after aortic prosthetic reconstruction

    SciTech Connect

    Tiesenhausen, Kurt; Hausegger, Klaus A.; Tauss, Josef; Amann, Wilfried; Koch, Guenter

    2001-01-15

    Purpose: To describe the efficacy and value of endovascular stent-grafts for the treatment of aortic anastomotic pseudo-aneurysms.Methods: Three patients with proximal aortic anastomotic pseudoaneurysms 8-15 years after prosthetic reconstruction were treated by transfemoral stent-graft implantation. In two patients the pseudoaneurysms were excluded by Talent prostheses [tube graft (n=1), bifurcated graft (n=s1)]. In one patient an uniiliac Zenith stent-graft was implanted and an extra-anatomic crossover bypass for revascularization of the contralateral lower extremity was performed.Results: All procedures were successful with primary exclusion of the pseudoaneurysms. During the follow-up (mean 16 months) one endoleak occurred due to migration of the tube stent-graft. The endoleak was sealed successfully by implanting an additional bifurcated stent-graft.Conclusion: Stent-graft exclusion of aortic pseudoaneurysms offers a minimally invasive and safe alternative to open surgical reconstruction.

  1. Successful treatment of an infected thoracic endovascular stent graft.

    PubMed

    Sueda, Taijiro; Takahashi, Shinya; Katayama, Keijiro; Imai, Katsuhiko

    2016-05-01

    A 70-year-old man with a chronic type B aortic dissection was treated with two stent grafts deployed in the descending thoracic aorta. The patient was re-admitted to the hospital at 16 months after thoracic endovascular stent grafting because of a high fever. A blood culture showed sepsis due to a Staphylococcus species. A CT scan showed an increase in the size of the thrombosed false lumen. Complete excision of the infected descending aortic wall and infected stent graft were performed. The descending thoracic aorta was reconstructed using a rifampicin-bonded Dacron graft and omental wrapping. The combination of in situ graft replacement using a rifampicin-bonded graft and omental wrapping is considered an effective treatment for thoracic stent graft infection. PMID:24990657

  2. Fusion Guidance in Endovascular Peripheral Artery Interventions: A Feasibility Study

    SciTech Connect

    Sailer, Anna M. Haan, Michiel W. de Graaf, Rick de Zwam, Willem H. van; Schurink, Geert Willem H.; Nelemans, Patricia J.; Wildberger, Joachim E. Das, Marco

    2015-04-15

    PurposeThis study was designed to evaluate the feasibility of endovascular guidance by means of live fluoroscopy fusion with magnetic resonance angiography (MRA) and computed tomography angiography (CTA).MethodsFusion guidance was evaluated in 20 endovascular peripheral artery interventions in 17 patients. Fifteen patients had received preinterventional diagnostic MRA and two patients had undergone CTA. Time for fluoroscopy with MRA/CTA coregistration was recorded. Feasibility of fusion guidance was evaluated according to the following criteria: for every procedure the executing interventional radiologists recorded whether 3D road-mapping provided added value (yes vs. no) and whether PTA and/or stenting could be performed relying on the fusion road-map without need for diagnostic contrast-enhanced angiogram series (CEAS) (yes vs. no). Precision of the fusion road-map was evaluated by recording maximum differences between the position of the vasculature on the virtual CTA/MRA images and conventional angiography.ResultsAverage time needed for image coregistration was 5 ± 2 min. Three-dimensional road-map added value was experienced in 15 procedures in 12 patients. In half of the patients (8/17), intervention was performed relying on the fusion road-map only, without diagnostic CEAS. In two patients, MRA roadmap showed a false-positive lesion. Excluding three patients with inordinate movements, mean difference in position of vasculature on angiography and MRA/CTA road-map was 1.86 ± 0.95 mm, implying that approximately 95 % of differences were between 0 and 3.72 mm (2 ± 1.96 standard deviation).ConclusionsFluoroscopy with MRA/CTA fusion guidance for peripheral artery interventions is feasible. By reducing the number of CEAS, this technology may contribute to enhance procedural safety.

  3. Endovascular Stenting for Unsuccessful Angioplasty of the Aorta in Aortoarteritis

    SciTech Connect

    Tyagi, Sanjay; Kaul, Upkar A.; Arora, Ramesh

    1999-11-15

    Purpose: The efficacy and safety of endovascular stent implantation to correct dissection or a suboptimal result after percutaneous transluminal angioplasty (PTA) was evaluated in patients suffering from aortic stenosis due to aortoarteritis. Methods: Twelve children and young adults [aged (mean {+-} SD) 18.2 {+-} 8.7 years] underwent stent implantation after PTA of the aorta, seven for obstructive dissection, four for ineffective balloon dilatation, and one for recurrent restenosis. Nine patients underwent implantation of self-expandable stents and three received balloon-expandable Palmaz stents. Results: Stent implantation could be successfully performed in all 12 patients. After stent implantation, the peak systolic pressure gradient decreased from 91 {+-} 33.5 mmHg to 12.4 {+-} 12.5 mmHg (p < 0.001). The diameter of the stenosed segment increased from 4.6 {+-} 0.8 mm to 11.1 {+-} 1.9 mm (p < 0.001). The dissection was completely covered in all seven patients with dissection. Except for epigastric pain with vomiting in one patient, there was no complication. On follow-up, over 12-57 months (mean 26.8 {+-} 10.8 months), 11 patients (91.6%) had marked improvement in their blood pressure. Patients with congestive heart failure and claudication also showed improvement. Repeat catheterization in five patients, between 6-30 months (mean 16.8 {+-} 9.1 months) after stent implantation, showed sustained improvement in four and a fusiform, long segment, intrastent restenosis after 30 months in one child. The stenosis was safely redilated. Conclusion: Endovascular aortic stent implantation is safe and provides good immediate relief in patients with unsatisfactory results after balloon angioplasty. Improvement is sustained in most patients on intermediate-term follow-up.

  4. Endovascular Therapeutic Approaches for Acute Superior Mesenteric Artery Occlusion

    SciTech Connect

    Acosta, S. Sonesson, B.; Resch, T.

    2009-09-15

    The purpose of this study was to characterize the outcome of attempted endovascular intervention in patients with acute embolic or thrombotic superior mesenteric artery (SMA) occlusion. The records of 21 patients during a 3-year period between 2005 and 2008 were retrieved from the in-hospital registry. The first group included 10 patients (6 women and 4 men; median age 78 years) with acute embolic occlusion of the SMA. The median duration of symptoms from symptom onset to angiography was 30 hours (range 6 to 120). Synchronous emboli (n = 12) occurred in 6 patients. Embolus aspiration was performed in 9 patients, and 7 of these had satisfactory results. Complementary local thrombolysis was successful in 2 of 3 patients. Residual emboli were present at completion angiography in all 7 patients who underwent successful aspiration embolectomy, and bowel resection was necessary in only 1 of these patients. One serious complication occurred because of a long SMA dissection. The in-hospital survival rate was 90% (9 of 10 patients). The second group included 11 patients (10 women and 1 man; median age 68 years) with atherosclerotic acute SMA occlusions. The median time of symptom duration before intervention was 97 hours (range 17 to 384). The brachial, femoral, and SMA routes were used in 6, 7, and 5 patients, respectively. SMA stenting was performed through an antegrade (n = 7) or retrograde (n = 3) approach. Bowel resection was necessary in 4 patients. No major complications occurred. The in-hospital survival rate was 82% (9 of 11 patients). Endovascular therapy of acute SMA occlusion provides a good alternative to open surgery.

  5. Clinical outcomes of endovascularly managed iatrogenic renal hemorrhages

    PubMed Central

    Chiramel, George Koshy; Keshava, Shyamkumar Nidugala; Moses, Vinu; Kekre, Nitin; Tamilarasi, V; Devasia, Anthony

    2015-01-01

    Objective: To evaluate the effectiveness of endovascular management in iatrogenic renal injuries with regard to clinical status on follow-up and requirements for repeat angiography and embolization. Materials and Methods: This retrospective study included patients who were referred for endovascular management of significant hemorrhage following an iatrogenic injury. Data was recorded from the Picture Archiving and Communication system (PACS) and electronic medical records. The site and type of iatrogenic injury, imaging findings, treatment, angiography findings, embolization performed, clinical status on follow-up, and requirement for repeat embolization were recorded. The outcomes were clinical resolution, nephrectomy, or death. Clinical findings were recorded on follow-up visits to the clinic. Statistical analysis was performed using descriptive statistics. Results: Seventy patients were included in this study between January 2000 and June 2012. A bleeding lesion (a pseudoaneurysm or arteriovenous fistula) was detected during the first angiogram in 55 patients (78.6%) and was selectively embolized. Fifteen required a second angiography as there was no clinical improvement and five required a third angiography. Overall, 66 patients (94.3%) showed complete resolution and 4 patients (5.7%) died. Three patients (4.3%) underwent nephrectomy for clinical stabilization even after embolization. There were no major complications. The two minor complications resolved spontaneously. Conclusions: Angiography and embolization is the treatment of choice in iatrogenic renal hemorrhage. Upto 20% of initial angiograms may not reveal the bleed and repeat angiography is required to identify a recurrent or unidentified bleed. The presence of multiple punctate bleeders on angiography suggests an enlarging subcapsular hematoma and requires preoperative embolization and nephrectomy. PMID:26752819

  6. Endovascular Treatment of Complications of Femoral Arterial Access

    SciTech Connect

    Tsetis, Dimitrios

    2010-06-15

    Endovascular repair of femoral arterial access complications is nowadays the treatment of choice in a group of patients who cannot tolerate vascular reconstruction and bleeding due to advanced cardiovascular disease. Endovascular procedures can be performed under local anesthesia, are well tolerated by the patient, and are associated with a short hospitalization time. Ninitinol stent technology allows for safe stent and stent-graft extension at the common femoral artery (CFA) level, due to increased resistance to external compression and bending stress. Active pelvic bleeding can be insidious, and prompt placement of a stent-graft at the site of leakage is a lifesaving procedure. Percutaneous thrombin injection under US guidance is the treatment of choice for femoral pseudoaneurysms (PAs); this can theoretically be safer with simultaneous balloon occlusion across the entry site of a PA without a neck or with a short and wide neck. In a few cases with thrombin failure due to a large arterial defect or accompanying arteriovenous fistula (AVF), a stent-graft can be deployed. The vast majority of catheter-induced AVFs can be treated effectively with stent-graft implantation even if they are located very close to the femoral bifurcation. Obstructive dissection flaps localized in the CFA are usually treated with prolonged balloon inflation; however, in more extensive dissections involving iliac arteries, self-expanding stents should be deployed. Iliofemoral thrombosis can be treated effectively with catheter-directed thrombolysis (CDT) followed by prolonged balloon inflation or stent placement. Balloon angioplasty and CDT can occasionally be used to treat stenoses and occlusions complicating the use of percutaneous closure devices.

  7. Endovascular Treatment of Aneurysmal Subarachnoid Hemorrhage in Japanese Registry of Neuroendovascular Therapy (JR-NET) 1 and 2

    PubMed Central

    IMAMURA, Hirotoshi; SAKAI, Nobuyuki; SAKAI, Chiaki; FUJINAKA, Toshiyuki; ISHII, Akira

    2014-01-01

    To distinguish the characteristics of ruptured cerebral aneurysm that are suitable for endovascular treatment from those that are not, we evaluated factors that influenced the results of aneurysm embolization in patients with ruptured cerebral aneurysm, based on data from the Japanese Registry of Neuroendovascular Therapy (JR-NET) 1 and 2. The multivariate analysis revealed that young patients, patients with low modified Rankin Scale (mRS) scores before onset, and patients with low World Federation of Neurosurgical Societies (WFNS) grades had good outcome. Compared to proximal internal carotid artery (ICA) aneurysms, the odds ratio of middle cerebral artery (MCA) aneurysms was 1.67, indicating poorer outcome for MCA aneurysms, and patients with small, wide-neck cerebral aneurysms had poor outcome. Patients treated after 15 days had better outcome than during other periods. The timing of treatment, however, did not influence the outcome in patients treated within 14 days. The outcome was poorer when the responsible doctor for the treatment was a specialist or a non-specialist than a supervisory doctor. The outcome of patients treated with bare platinum coils, and three dimensional (3D) rotational angiography was better, and the outcome of patients who completed treatment with body filling was poorer than in patients with complete occlusion. Perioperative hemorrhagic complications, all ischemic complications, and rebleeding occurred in 4.5%, 6.4%, and 1.4% of patients, respectively. All these complications had poor outcome factors on day 30, with odds ratios of 2.72, 2.96, and 25.49, respectively. We must be fully aware of these risk factors and determine indications for the treatment when endovascular treatment is performed as the treatment of choice for ruptured cerebral aneurysm. PMID:24390181

  8. Outcomes of Infrainguinal Revascularizations with Endovascular First Strategy in Critical Limb Ischemia

    SciTech Connect

    Jens, Sjoerd; Conijn, Anne P. Frans, Franceline A.; Nieuwenhuis, Marieke B. B. Met, Rosemarie; Koelemay, Mark J. W. Legemate, Dink A.; Bipat, Shandra Reekers, Jim A.

    2015-06-15

    PurposeThis study was designed to study the outcome of infrainguinal revascularization in patients with critical limb ischemia (CLI) in an institution with a preference towards endovascular intervention first in patients with poor condition, unfavourable anatomy for surgery, no venous material for bypass, and old age.MethodsA prospective, observational cohort study was conducted between May 2007 and May 2010 in patients presenting with CLI. At baseline, the optimal treatment was selected, i.e., endovascular or surgical treatment. In case of uncertainty about the preferred treatment, a multidisciplinary team (MDT) was consulted. Primary endpoints were quality of life and functional status 6 and 12 months after initial intervention, assessed by the VascuQol and AMC Linear Disability Score questionnaires, respectively.ResultsIn total, 113 patients were included; 86 had an endovascular intervention and 27 had surgery. During follow-up, 41 % underwent an additional ipsilateral revascularisation procedure. For the total population, and endovascular and surgery subgroups, the VascuQol sum scores improved after 6 and 12 months (p < 0.01 for all outcomes) compared with baseline. The functional status improved (p = 0.043) after 12 months compared with baseline for the total population. Functional status of the surgery subgroup improved significantly after 6 (p = 0.031) and 12 (p = 0.044) months, but not that of the endovascular subgroup.ConclusionsOverall, the strategy of performing endovascular treatment first in patients with poor condition, unfavourable anatomy for surgery, no venous material for bypass, and old age has comparable or even slightly better results compared with the BASIL trial and other cohort studies. All vascular groups should discuss whether their treatment strategy should be directed at treating CLI patients preferably endovascular first and consider implementing an MDT to optimize patient outcomes.

  9. Image-based analysis of blood flow modification in stented aneurysms

    NASA Astrophysics Data System (ADS)

    Cebral, Juan; Mut, Fernando; Appanaboyina, Sunil; Löhner, Rainald; Miranda, Carlos; Escrivano, Esteban; Lylyk, Pedro; Putman, Christopher

    2009-02-01

    Currently there is increased interest in the use of stents as flow diverters for the treatment of intracranial aneurysms, especially wide necked aneurysms that are difficult to treat by coil embolization or surgical clipping. This paper presents image-based patient-specific computational models of the hemodynamics in cerebral aneurysms before and after treatment with a stent alone, with the goal of better understanding the hemodynamic effects of these devices and their relation to the outcome of the procedures. Stenting of cerebral aneurysms is a feasible endovascular treatment option for aneurysms with wide necks that are difficult to treat with coils or by surgical clipping. However, this requires stents that are capable of substantially modifying the intra-aneurysmal flow pattern in order to cause thrombosis of the aneurysm. The results presented in this paper show that the studied stent was able to change significantly the hemodynamic characteristics of the aneurysm. In addition, it was shown that patient-specific computational models constructed from medical images are capable of realistically representing the in vivo hemodynamic characteristics observed during conventional angiography examinations before and after stenting. This indicates that these models can be used to better understand the effects of different stent designs and to predict the alteration in the hemodynamic pattern of a given aneurysm produced by a given flow diverter. This is important for improving current design of flow diverting devices and patient treatment plans.

  10. Thoracic endovascular aortic repair for complicated chronic type B aortic dissection in a patient on hemodialysis with recurrent ischemic colitis.

    PubMed

    Miyazaki, Yuko; Furuyama, Tadashi; Matsubara, Yutaka; Yoshiya, Keiji; Yoshiga, Ryosuke; Inoue, Kentaro; Matsuda, Daisuke; Aoyagi, Yukihiko; Kato, Masaaki; Matsumoto, Takuya; Maehara, Yoshihiko

    2016-12-01

    We present a successful case of thoracic endovascular aortic repair (TEVAR) for chronic Stanford type B aortic dissection (B-AD) with recurrent ischemic colitis. The patient was a 56-year-old woman with abdominal pain as the main complaint who had two operations previously: the total arch replacement 8 years ago and the Bentall 7 years ago for acute Stanford type A aortic dissection. Her abdominal pain worsened as her blood pressure became low during her hemodialysis treatment. An enhanced computed tomography scan was performed on the patient and showed chronic B-AD that occurred from the distal anastomotic part of the total arch graft to the bilateral common iliac arteries. The celiac artery and superior mesenteric artery (SMA) arose from the true lumen, and these were compressed by the expanded false lumen. Her complicated chronic B-AD was treated with the Zenith Dissection Endovascular System, and its procedure was performed as her proximal entry tear was covered by a proximal tapered Zenith TX2 stent graft, supplemented by a noncovered aortic stent extending across both renal arteries, the SMA, and the celiac artery. Seven days after this operation, enhanced computed tomography showed that the patient's true lumen was expanded and her blood flow to the true lumen and SMA was improved. On the other hand, her false lumen tended to be thrombosed. Consequently, she was discharged 10 days after the operation without any postoperative complications as she had no abdominal complaints even though she underwent hemodialysis three times per week after the operation. We believe that TEVAR supplemented by a noncovered aortic stent is an effective treatment, even for highly chronic B-AD in dialysis patients. PMID:27090121

  11. Customized Tapered Stent-Grafts in the Endovascular Management of Internal Iliac Artery Aneurysms: A Useful Adjunct to Conventional Endovascular Options

    SciTech Connect

    Haslam, J. Elizabeth Hardman, John; Horrocks, Michael; Fay, Dominic

    2009-01-15

    The endovascular exclusion of an isolated iliac artery aneurysm is recognized as a safe and favorable alternative to open surgical repair, with low associated morbidity and mortality. It has particular advantages in the treatment of internal iliac artery aneurysm (IIAA) given the technical difficulties associated with open surgical repair deep within the pelvis. We describe the use of customized tapered stent-grafts in the exclusion of wide-necked IIAA in five male patients considered high-risk for conventional surgical repair, in whom the common and external iliac artery morphology precluded the use of standard endovascular devices. In each case, IIAA outflow was selectively embolized and the aneurysm neck excluded by placement of a customized tapered stent-graft across the internal iliac artery origin. This technique was extremely effective, with 100% technical success, no serious associated morbidity, and zero mortality. In all five patients sac size was stable or reduced on computed tomography follow-up of up to 3 years (mean, 24.4 months), with a primary patency rate of 100%. We therefore advocate the use of customized tapered stent-grafts as a further endovascular option in the management of IIAA unsuitable for conventional endovascular repair.

  12. Intravenous thrombolysis or endovascular therapy for acute ischemic stroke associated with cervical internal carotid artery occlusion: the ICARO-3 study.

    PubMed

    Paciaroni, Maurizio; Inzitari, Domenico; Agnelli, Giancarlo; Caso, Valeria; Balucani, Clotilde; Grotta, James C; Sarraj, Amrou; Sung-Il, Sohn; Chamorro, Angel; Urra, Xabier; Leys, Didier; Henon, Hilde; Cordonnier, Charlotte; Dequatre, Nelly; Aguettaz, Pierre; Alberti, Andrea; Venti, Michele; Acciarresi, Monica; D'Amore, Cataldo; Zini, Andrea; Vallone, Stefano; Dell'Acqua, Maria Luisa; Menetti, Federico; Nencini, Patrizia; Mangiafico, Salvatore; Barlinn, Kristian; Kepplinger, Jessica; Bodechtel, Ulf; Gerber, Johannes; Bovi, Paolo; Cappellari, Manuel; Linfante, Italo; Dabus, Guilherme; Marcheselli, Simona; Pezzini, Alessandro; Padovani, Alessandro; Alexandrov, Andrei V; Shahripour, Reza Bavarsad; Sessa, Maria; Giacalone, Giacomo; Silvestrelli, Giorgio; Lanari, Alessia; Ciccone, Alfonso; De Vito, Alessandro; Azzini, Cristiano; Saletti, Andrea; Fainardi, Enrico; Orlandi, Giovanni; Chiti, Alberto; Gialdini, Gino; Silvestrini, Mauro; Ferrarese, Carlo; Beretta, Simone; Tassi, Rossana; Martini, Giuseppe; Tsivgoulis, Georgios; Vasdekis, Spyros N; Consoli, Domenico; Baldi, Antonio; D'Anna, Sebastiano; Luda, Emilio; Varbella, Ferdinando; Galletti, Giampiero; Invernizzi, Paolo; Donati, Edoardo; De Lodovici, Maria Luisa; Bono, Giorgio; Corea, Francesco; Sette, Massimo Del; Monaco, Serena; Riva, Maurizio; Tassinari, Tiziana; Scoditti, Umberto; Toni, Danilo

    2015-02-01

    The aim of the ICARO-3 study was to evaluate whether intra-arterial treatment, compared to intravenous thrombolysis, increases the rate of favourable functional outcome at 3 months in acute ischemic stroke and extracranial ICA occlusion. ICARO-3 was a non-randomized therapeutic trial that performed a non-blind assessment of outcomes using retrospective data collected prospectively from 37 centres in 7 countries. Patients treated with endovascular treatment within 6 h from stroke onset (cases) were matched with patients treated with intravenous thrombolysis within 4.5 h from symptom onset (controls). Patients receiving either intravenous or endovascular therapy were included among the cases. The efficacy outcome was disability at 90 days assessed by the modified Rankin Scale (mRS), dichotomized as favourable (score of 0-2) or unfavourable (score of 3-6). Safety outcomes were death and any intracranial bleeding. Included in the analysis were 324 cases and 324 controls: 105 cases (32.4 %) had a favourable outcome as compared with 89 controls (27.4 %) [adjusted odds ratio (OR) 1.25, 95 % confidence interval (CI) 0.88-1.79, p = 0.1]. In the adjusted analysis, treatment with intra-arterial procedures was significantly associated with a reduction of mortality (OR 0.61, 95 % CI 0.40-0.93, p = 0.022). The rates of patients with severe disability or death (mRS 5-6) were similar in cases and controls (30.5 versus 32.4 %, p = 0.67). For the ordinal analysis, adjusted for age, sex, NIHSS, presence of diabetes mellitus and atrial fibrillation, the common odds ratio was 1.15 (95 % IC 0.86-1.54), p = 0.33. There were more cases of intracranial bleeding (37.0 versus 17.3 %, p = 0.0001) in the intra-arterial procedure group than in the intravenous group. After the exclusion of the 135 cases treated with the combination of I.V. thrombolysis and I.A. procedures, 67/189 of those treated with I.A. procedures (35.3 %) had a favourable outcome, compared to 89/324 of

  13. Endovascular Mechanical Recanalisation of Acute Carotid-T Occlusions: A Single-Center Retrospective Analysis

    SciTech Connect

    Fesl, Gunther; Wiesmann, Martin; Patzig, Maximilian; Holtmannspoetter, Markus; Pfefferkorn, Thomas; Dichgans, Martin; Brueckmann, Hartmut

    2011-04-15

    Purpose: Acute carotid-T occlusion generally responds poorly to thrombolysis. Endovascular mechanical thrombectomy (EMT) seems to be a promising alternative. However, there are few data on EMT in carotid-T occlusions. Materials and Methods: We reviewed data of 14 consecutive patients with acute carotid-T occlusions treated with mechanical recanalisation devices. A clot separation/aspiration system was used in 11 patients; different other mechanical retriever devices were used in seven patients; and stents were used in four patients. Modified Rankin Scale scores at 90 days were recorded to assess functional outcome. Results: Six women and eight men were included in the study. Mean patient age was 59.2 years; median National Institute of Health Stroke Scale score on admission was 19; and mean time to treatment was 4.2 h. Successful recanalisation (Thrombolysis in Myocardial Infarction [TIMI] score II and III) was achieved in 11 patients (78.6%). Seven patients (50.0%) were treated with more than one device, leading to successful recanalisation in six of these patients (85.7%). Subarachnoid haemorrhage and large space-occupying bleedings occurred in one (7.1%) and three (21.4%) patients, respectively. At follow-up, three patients (21.4%) were functionally independent, and six (42.9%) had died. Conclusion: When applying different mechanical devices, we found a high recanalisation rate. However, discrepancy between recanalisation and clinical outcome remained. More data are needed to assess the effect of the different methods on the prognoses of stroke patients.

  14. Acute middle cerebral artery occlusion: reappraisal of the role of endovascular revascularization.

    PubMed

    Cohen, José E

    2013-02-01

    Intravenous tissue plasminogen activator was the first successful stroke therapy in acute ischaemic stroke, after innumerable failed attempts at neuroprotection and neurorestoration. However, intravenous tissue type plasminogen activator has been shown to be effective in recanalizing middle cerebral artery occlusions in only about one-third of cases. The natural history of untreated acute middle cerebral artery occlusion is poor, leading to long-term disability in >70% and mortality in 20%. Recanalization alone is not the name of the game. Only timely, very rapid recanalization, achieved within minutes or at most a few hours after stroke has occurred, before irreversible brain damage develops, is effective. Is intravenous tissue type plasminogen activator the best available option we have for these patients? With recently introduced stent-based thrombectomy devices, neurointerventionalists have achieved complete recanalization rates of more than 90% in middle cerebral artery and 'T' occlusions, with a mean procedural recanalization time of less than one-hour and negligible complication rates. More than 80% of patients less than 80 years of age who were treated within eight-hours after stroke onset in our centre achieved a modified Rankin score of 0-2 at three-month follow-up. The site of arterial occlusion is a factor driving the choice between a standard intravenous tissue type plasminogen activator protocol and an alternative intervention such as intravenous and/or mechanical thrombolysis to achieve early recanalization. The role of intravenous tissue type plasminogen activator must be redefined in major occlusions, and the indications for endovascular therapy must also be reappraised. PMID:23336262

  15. Endovascular Repair of Acute Symptomatic Pararenal Aortic Aneurysm With Three Chimney and One Periscope Graft for Complete Visceral Artery Revascularization

    SciTech Connect

    Brechtel, Klaus Ketelsen, Dominik; Endisch, Andrea; Heller, Stephan; Heuschmid, Martin; Stock, Ulrich A.; Kalender, Guenay

    2012-04-15

    PurposeTo describe a modified endovascular technique for complete revascularization of visceral and renal arteries in symptomatic pararenal aortic aneurysm (PRAA).TechniqueArterial access was surgically established in both common femoral arteries (CFAs) and the left subclavian artery (LSA). Revascularization of the left renal artery, the celiac trunk, and the superior mesenteric artery was performed through one single sheath via the LSA. Suitable covered stents were put in the aortic branches but not deployed. The right renal artery was accessed over the left CFA. Due to the longitudinal extension of the presented aneurysm two stent-grafts were introduced via the right CFA. After deploying the aortic stent-grafts, all covered stents in the side branches were deployed consecutively with a minimum overlap of 5 mm over the cranial and caudal stent-graft edges. Simultaneous ballooning was performed to fully expand all stent-grafts and warranty patency. Conclusion: This is the first report in the literature of chimney grafting in PRAA for complete revascularization of visceral and renal branches by using more than two covered stents introduced from one side through one single sheath. However this technique is modified, it should be used only in bailout situations when branched stent-grafts are not available and/or surgery is not suitable.

  16. Endovascular Treatment of Bilateral Pulmonary Artery Stenoses and Superior Vena Cava Syndrome in a Patient with Advanced Mediastinal Fibrosis

    PubMed Central

    Kuban, Joshua D.; Ramanathan, Rohit; Whigham, Cliff J.

    2016-01-01

    Vascular stenosis is a relatively uncommon and often fatal sequela of mediastinal fibrosis. There are very few reports in the medical literature of endovascular treatment for concomitant bilateral pulmonary artery stenoses and superior vena cava syndrome. We report the endovascular treatment of these conditions in a 54-year-old man, and the long-term outcome. PMID:27303243

  17. Endovascular stent grafting of a posterior tibial artery pseudoaneurysm secondary to penetrating trauma: case report and review of the literature.

    PubMed

    de Troia, Alessandro; Biasi, Lukla; Iazzolino, Luigi; Azzarone, Matteo; Tecchio, Tiziano; Rossi, Cristina; Salcuni, Pierfranco

    2014-10-01

    Endovascular treatment of posttraumatic pseudoaneurysms has become a viable less-invasive option when compared with open repair. In this study, we present a case of a posttraumatic pseudoaneurysm of the posterior tibial artery in a 34-year-old man treated with endovascular stent grafting. An extensive review of the literature has been performed. PMID:24530718

  18. Endovascular Broad-Neck Aneurysm Creation in a Porcine Model Using a Vascular Plug

    SciTech Connect

    Muehlenbruch, Georg Nikoubashman, Omid; Steffen, Bjoern; Dadak, Mete; Palmowski, Moritz; Wiesmann, Martin

    2013-02-15

    Ruptured cerebral arterial aneurysms require prompt treatment by either surgical clipping or endovascular coiling. Training for these sophisticated endovascular procedures is essential and ideally performed in animals before their use in humans. Simulators and established animal models have shown drawbacks with respect to degree of reality, size of the animal model and aneurysm, or time and effort needed for aneurysm creation. We therefore aimed to establish a realistic and readily available aneurysm model. Five anticoagulated domestic pigs underwent endovascular intervention through right femoral access. A total of 12 broad-neck aneurysms were created in the carotid, subclavian, and renal arteries using the Amplatzer vascular plug. With dedicated vessel selection, cubic, tubular, and side-branch aneurysms could be created. Three of the 12 implanted occluders, two of them implanted over a side branch of the main vessel, did not induce complete vessel occlusion. However, all aneurysms remained free of intraluminal thrombus formation and were available for embolization training during a surveillance period of 6 h. Two aneurysms underwent successful exemplary treatment: one was stent-assisted, and one was performed with conventional endovascular coil embolization. The new porcine aneurysm model proved to be a straightforward approach that offers a wide range of training and scientific applications that might help further improve endovascular coil embolization therapy in patients with cerebral aneurysms.

  19. Evaluation of cerebral oximetry during endovascular treatment of carotid-cavernous fistula

    NASA Astrophysics Data System (ADS)

    Dujovny, Manuel; Misra, Mukesh; Alp, M. Serdar; Debrun, Gerard; Charbel, F. T.; Aletich, Victor; Ausman, James I.

    1997-08-01

    Endovascular treatment of carotid cavernous fistula is done routinely in our institution. We have been monitoring these patients with transcranial cerebral oximetry. The transcranial cerebral oximeter is a reliable, low-cost, non-invasive device that provides real-time evaluation of regional brain oxygen saturation during and after endovascular treatment of cerebrovascular diseases. We used the INVOS 3100A (Somanetics, Troy, MI) in our study. We discuss seven patients with carotid-cavernous fistulas treated by endovascular balloon occlusion, each monitored continuously before, during, and after the procedure with transcranial cerebral oximetry. The cerebral oxygen saturation depicted was directly related to the side of the venous drainage of the fistula, with the brain oxygen saturation 15 - 20% higher on the side of the venous drainage. Following endovascular occlusion of the fistula, oxygen saturation gradually became equal on both sides. In our patients treated for carotid-cavernous fistula, we evaluated the sensitivity and usefulness of cerebral oximetry as an important non-invasive monitoring tool for the endovascular treatment of carotid-cavernous fistula.

  20. A Novel Technique for Endovascular Removal of Large Volume Right Atrial Tumor Thrombus

    SciTech Connect

    Nickel, Barbara; McClure, Timothy Moriarty, John

    2015-08-15

    Venous thromboembolic disease is a significant cause of morbidity and mortality, particularly in the setting of large volume pulmonary embolism. Thrombolytic therapy has been shown to be a successful treatment modality; however, its use somewhat limited due to the risk of hemorrhage and potential for distal embolization in the setting of large mobile thrombi. In patients where either thrombolysis is contraindicated or unsuccessful, and conventional therapies prove inadequate, surgical thrombectomy may be considered. We present a case of percutaneous endovascular extraction of a large mobile mass extending from the inferior vena cava into the right atrium using the Angiovac device, a venovenous bypass system designed for high-volume aspiration of undesired endovascular material. Standard endovascular methods for removal of cancer-associated thrombus, such as catheter-directed lysis, maceration, and exclusion, may prove inadequate in the setting of underlying tumor thrombus. Where conventional endovascular methods either fail or are unsuitable, endovascular thrombectomy with the Angiovac device may be a useful and safe minimally invasive alternative to open resection.

  1. Endovascular Electrodes for Electrical Stimulation of Blood Vessels for Vasoconstriction - a Finite Element Simulation Study.

    PubMed

    Kezurer, Noa; Farah, Nairouz; Mandel, Yossi

    2016-01-01

    Hemorrhagic shock accounts for 30-40 percent of trauma mortality, as bleeding may sometimes be hard to control. Application of short electrical pulses on blood vessels was recently shown to elicit robust vasoconstriction and reduction of blood loss following vascular injury. In this study we present a novel approach for vasoconstriction based on endovascular application of electrical pulses for situations where access to the vessel is limited. In addition to ease of access, we hypothesize that this novel approach will result in a localized and efficient vasoconstriction. Using computer modeling (COMSOL Multiphysics, Electric Currents Module), we studied the effect of endovascular pulsed electrical treatment on abdominal aorta of pigs, and compared the efficiency of different electrodes configurations on the electric field amplitude, homogeneity and locality when applied on a blood vessel wall. Results reveal that the optimal configuration is the endovascular approach where four electrodes are used, spaced 13 mm apart. Furthermore, computer based temperature investigations (bio-heat model, COMSOL Multiphysics) show that the maximum expected temperature rise is of 1.2 degrees; highlighting the safety of the four endovascular electrodes configuration. These results can aid in planning the application of endovascular pulsed electrical treatment as an efficient and safe vasoconstriction approach. PMID:27534438

  2. Endovascular Electrodes for Electrical Stimulation of Blood Vessels for Vasoconstriction – a Finite Element Simulation Study

    PubMed Central

    Kezurer, Noa; Farah, Nairouz; Mandel, Yossi

    2016-01-01

    Hemorrhagic shock accounts for 30–40 percent of trauma mortality, as bleeding may sometimes be hard to control. Application of short electrical pulses on blood vessels was recently shown to elicit robust vasoconstriction and reduction of blood loss following vascular injury. In this study we present a novel approach for vasoconstriction based on endovascular application of electrical pulses for situations where access to the vessel is limited. In addition to ease of access, we hypothesize that this novel approach will result in a localized and efficient vasoconstriction. Using computer modeling (COMSOL Multiphysics, Electric Currents Module), we studied the effect of endovascular pulsed electrical treatment on abdominal aorta of pigs, and compared the efficiency of different electrodes configurations on the electric field amplitude, homogeneity and locality when applied on a blood vessel wall. Results reveal that the optimal configuration is the endovascular approach where four electrodes are used, spaced 13 mm apart. Furthermore, computer based temperature investigations (bio-heat model, COMSOL Multiphysics) show that the maximum expected temperature rise is of 1.2 degrees; highlighting the safety of the four endovascular electrodes configuration. These results can aid in planning the application of endovascular pulsed electrical treatment as an efficient and safe vasoconstriction approach. PMID:27534438

  3. An Aortoenteric Fistula Arising after Endovascular Management of a Mycotic Abdominal Aortic Aneurysm Complicated with a Psoas Abscess

    PubMed Central

    Gülcü, Aytaç; Gezer, Naciye Sinem; Uğurlu, Şevket Baran; Göktay, Ahmet Yiğit

    2016-01-01

    Mycotic aortic aneurysms account for 1–3% of all aortic aneurysms. The management of this disease is controversial. Since open surgical repair is associated with high morbidity and mortality rates, endovascular aneurysm repair is an alternative treatment method with promising early and midterm outcomes, although its long-term durability is unknown. Secondary aortoenteric fistulas may occur iatrogenically after either aortic reconstructive surgery or endovascular repair. As the number of aneurysms managed with endovascular aneurysm repair has substantially increased, cases of aortoenteric fistulas referred for endovascular repair are augmented. We report the case of an aortoduodenal fistula manifested with duodenal perforation after staged endovascular and surgical treatment of a mycotic aortic aneurysm. PMID:27365559

  4. An Aortoenteric Fistula Arising after Endovascular Management of a Mycotic Abdominal Aortic Aneurysm Complicated with a Psoas Abscess.

    PubMed

    Gülcü, Aytaç; Gezer, Naciye Sinem; Uğurlu, Şevket Baran; Göktay, Ahmet Yiğit

    2016-07-01

    Mycotic aortic aneurysms account for 1-3% of all aortic aneurysms. The management of this disease is controversial. Since open surgical repair is associated with high morbidity and mortality rates, endovascular aneurysm repair is an alternative treatment method with promising early and midterm outcomes, although its long-term durability is unknown. Secondary aortoenteric fistulas may occur iatrogenically after either aortic reconstructive surgery or endovascular repair. As the number of aneurysms managed with endovascular aneurysm repair has substantially increased, cases of aortoenteric fistulas referred for endovascular repair are augmented. We report the case of an aortoduodenal fistula manifested with duodenal perforation after staged endovascular and surgical treatment of a mycotic aortic aneurysm. PMID:27365559

  5. A Comparative Study on Johnson Cook, Modified Zerilli-Armstrong and Arrhenius-Type Constitutive Models to Predict High-Temperature Flow Behavior of Ti-6Al-4V Alloy in α + β Phase

    NASA Astrophysics Data System (ADS)

    Cai, Jun; Wang, Kuaishe; Han, Yingying

    2016-03-01

    True stress and true strain values obtained from isothermal compression tests over a wide temperature range from 1,073 to 1,323 K and a strain rate range from 0.001 to 1 s-1 were employed to establish the constitutive equations based on Johnson Cook, modified Zerilli-Armstrong (ZA) and strain-compensated Arrhenius-type models, respectively, to predict the high-temperature flow behavior of Ti-6Al-4V alloy in α + β phase. Furthermore, a comparative study has been made on the capability of the three models to represent the elevated temperature flow behavior of Ti-6Al-4V alloy. Suitability of the three models was evaluated by comparing both the correlation coefficient R and the average absolute relative error (AARE). The results showed that the Johnson Cook model is inadequate to provide good description of flow behavior of Ti-6Al-4V alloy in α + β phase domain, while the predicted values of modified ZA model and the strain-compensated Arrhenius-type model could agree well with the experimental values except under some deformation conditions. Meanwhile, the modified ZA model could track the deformation behavior more accurately than other model throughout the entire temperature and strain rate range.

  6. Design and biocompatibility of endovascular aneurysm filling devices

    DOE PAGESBeta

    Rodriguez, Jennifer N.; Hwang, Wonjun; Horn, John; Landsman, Todd L.; Boyle, Anthony; Wierzbicki, Mark A.; Hasan, Sayyeda M.; Follmer, Douglas; Bryant, Jesse; Small, Ward; et al

    2014-08-04

    We report that the rupture of an intracranial aneurysm, which can result in severe mental disabilities or death, affects approximately 30,000 people in the United States annually. The traditional surgical method of treating these arterial malformations involves a full craniotomy procedure, wherein a clip is placed around the aneurysm neck. In recent decades, research and device development have focused on new endovascular treatment methods to occlude the aneurysm void space. These methods, some of which are currently in clinical use, utilize metal, polymeric, or hybrid devices delivered via catheter to the aneurysm site. In this review, we present several suchmore » devices, including those that have been approved for clinical use, and some that are currently in development. We present several design requirements for a successful aneurysm filling device and discuss the success or failure of current and past technologies. Lastly, we also present novel polymeric based aneurysm filling methods that are currently being tested in animal models that could result in superior healing.« less

  7. Design and biocompatibility of endovascular aneurysm filling devices

    SciTech Connect

    Rodriguez, Jennifer N.; Hwang, Wonjun; Horn, John; Landsman, Todd L.; Boyle, Anthony; Wierzbicki, Mark A.; Hasan, Sayyeda M.; Follmer, Douglas; Bryant, Jesse; Small, Ward; Maitland, Duncan J.

    2014-08-04

    We report that the rupture of an intracranial aneurysm, which can result in severe mental disabilities or death, affects approximately 30,000 people in the United States annually. The traditional surgical method of treating these arterial malformations involves a full craniotomy procedure, wherein a clip is placed around the aneurysm neck. In recent decades, research and device development have focused on new endovascular treatment methods to occlude the aneurysm void space. These methods, some of which are currently in clinical use, utilize metal, polymeric, or hybrid devices delivered via catheter to the aneurysm site. In this review, we present several such devices, including those that have been approved for clinical use, and some that are currently in development. We present several design requirements for a successful aneurysm filling device and discuss the success or failure of current and past technologies. Lastly, we also present novel polymeric based aneurysm filling methods that are currently being tested in animal models that could result in superior healing.

  8. Iatrogenic intracranial pseudoaneurysms: neuroradiological and therapeutical considerations, including endovascular options.

    PubMed

    Ciceri, E F M; Regna-Gladin, C; Erbetta, A; Chiapparini, L; Nappini, S; Savoiardo, M; Di Meco, F

    2006-11-01

    Intracranial pseudoaneurysms represent a potentially fatal complication of intracranial surgery. Our purpose is to describe their neuroradiological characteristics, prognostic features and possible treatment. Eight cases of postsurgical intracranial pseudoaneurysms have been observed at our institution since 1988. Four were observed following transsphenoidal (TS) surgery and four after pterional craniotomies. Two types of iatrogenic pseudoaneurysms were observed: "fusiform", probably due to weakening of the adventitia during surgical peeling of the tumour from the artery (three cases) and "saccular", occurring after a more focal or complete laceration of the vessel (five cases), more often after TS surgery. A thorough preoperative neuroradiological examination may identify anatomical conditions at risk for development of this severe complication. Postoperative neuroradiological follow-up is mandatory in cases in which unusual bleeding has occurred during the perioperative period, but absence of bleeding does not exclude the possible development of a pseudoaneurysm. Endovascular treatment of pseudoaneurysms represents a safe and durable procedure, specifically in those cases in which damage to the carotid siphon occurred during TS surgery. PMID:17122940

  9. Endovascular Stent Placement for Hemodialysis Arteriovenous Access Stenosis.

    PubMed

    Neuen, Brendon L; Baer, Richard A; Grainer, Frank; Mantha, Murty L

    2015-01-01

    This study aims to report the outcomes of nitinol and polytetrafluoroethylene covered stent placement to treat hemodialysis arteriovenous access stenosis at a single center over a five-year period. Clinical and radiological information was reviewed retrospectively. Poststent primary and secondary patency rates were determined using Kaplan-Meier analysis. Ten clinical variables were subjected to multivariate Cox regression analysis to determine predictors of patency after stent placement. During the study period 60 stents were deployed in 45 patients, with a mean follow-up of 24.5 months. The clinical and anatomical success rate was 98.3% (59/60). Poststent primary patency rates at 6, 12, and 24 months were 64%, 46%, and 35%, respectively. Poststent secondary patency rates at 6, 12, and 24 months were 95%, 89%, and 85%, respectively. Stent placement for upper arm lesions and in access less than 12 months of age was associated with reduced primary patency (adjusted hazards ratio [HR] 5.1, p = 0.0084, and HR 3.5, p = 0.0029, resp.). Resistant or recurrent stenosis can be successfully treated by endovascular stent placement with durable long-term patency, although multiple procedures are often required. Stent placement for upper arm lesions and in arteriovenous access less than 12 months of age was associated with increased risk of patency loss. PMID:26649199

  10. Endovascular Treatment of Chronic Mesenteric Ischemia: Report of Five Cases

    SciTech Connect

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

    1998-07-15

    Purpose: To evaluate the midterm results of percutaneous transluminal angioplasty (PTA) and stent placement in stenotic and occluded mesenteric arteries in five consecutive patients with chronic mesenteric ischemia. Methods: Five patients with 70%-100% obliterations of all mesenteric vessels resulting in chronic mesenteric ischemia (n= 4) and as a prophylactic measure prior to abdominal aortic aneurysm repair (n= 1) underwent PTA of celiac and/or superior mesenteric artery (SMA) stenoses (n= 2), primary stenting of ostial celiac occlusions (n= 2), and secondary stenting of a SMA occlusion (n= 1; recoil after initial PTA). All patients underwent duplex ultrasonography (US) (n= 3) and/or angiography (n= 5) during a median follow-up of 21 months (range 8-42 months). Results: Clinical success was obtained in all five patients. Asymptomatic significant late restenoses (n3) were successfully treated with repeat PTA (n= 2) and stenting of an SMA occlusion (n= 1; celiac stent restenosis). Recurrent pain in one patient was interpreted as secondary to postsurgical abdominal adhesions. Two puncture-site complications occurred requiring local surgical treatment. Conclusions: Endovascular techniques may be attempted prior to surgery in cases of stenotic or short occlusive lesions in patients with chronic mesenteric ischemia. Surgery may still be preferred in patients with long occlusions and a low operative risk.

  11. [Peri-interventional management of acute endovascular stroke treatment].

    PubMed

    Schönenberger, S; Bösel, J

    2015-10-01

    Due to the ground breaking consistent evidence that supports the effect of endovascular stroke treatment (EST), many acute care hospitals and stroke centers will have to be prepared to provide this treatment in an optimal way within the coming years. In addition to the intervention itself, patient preparation, stabilization and monitoring during the treatment as well as the aftercare represent significant challenges and have mostly not yet been sufficiently investigated. Under these aspects, the questions of optimal sedation and airway management have received the highest attention. Based on retrospective study results it already seems to be justified, respecting certain criteria, to prefer EST with the patient under conscious sedation (CS) in comparison to general anesthesia (GA) and to only switch to GA in cases of emergency until this question has been clarified by prospective studies. This and other aspects of peri-interventional management, such as logistics, monitoring, blood pressure, ventilation settings, postprocedural steps of intensive or stroke unit care and imaging follow-up are summarized in this overview. The clinical and radiological selection of patients and thus the decision for intervention or technical aspects of the intervention itself will not be part of this article. PMID:26311331

  12. Catheter venography and endovascular treatment of chronic cerebrospinal venous insufficiency.

    PubMed

    Mandato, Kenneth; Englander, Meridith; Keating, Lawrence; Vachon, Jason; Siskin, Gary P

    2012-06-01

    Multiple sclerosis (MS) is a disorder characterized by damage to the myelin sheath insulation of nerve cells of the brain and spinal cord affecting nerve impulses which can lead to numerous physical and cognitive disabilities. The disease, which affects over 500,000 people in the United States alone, is widely believed to be an autoimmune condition potentially triggered by an antecedant event such as a viral infection, environmental factors, a genetic defect or a combination of each. Chronic cerebrospinal venous insufficiency (CCSVI) is a condition characterized by abnormal venous drainage from the central nervous system that has been theorized to have a possible role in the pathogenesis and symptomatology of MS (1). A significant amount of attention has been given to this theory as a possible explanation for the etiology of symptoms related to MS patients suffering from this disease. The work of Dr. Zamboni, et al, who reported that treating the venous stenoses causing CCSVI with angioplasty resulting in significant improvement in the symptoms and quality of life of patients with MS (2) has led to further interest in this theory and potential treatment. The article presented describes endovascular techniques employed to diagnose and treat patients with MS and CCSVI. PMID:22640501

  13. Endovascular Treatment of Cerebral AVM: Our Experience with Onyx

    PubMed Central

    Pérez-Higueras, A.; Rossi López, R.; Quiñones Tapia, D.

    2005-01-01

    Summary We have been using Onyx, a non-adhesive liquid polymer, to treat cerebral AVMs endovascularly since 1999. During this time we have treated 45 consecutive, unselected patients. From the outset this product brought about a change in our approach to treating this type of lesion because of the different injection behaviour observed for this material compared with the adhesive Histoacryl that had been employed until then. The object of this article is to assess the results achieved by our team using this new embolic agent, following angiographic and clinical follow-up of cases for a minimum of six months and a maximum of five years (mean: two years). We propose new categories of cerebral AVM based on the expected behaviour of Onyx within the nidus. Our appraisal indicates that we have improved our angiographic results, achieving complete occlusion of the malformation in 22% of cases and over 80-% closure in 69% of cases. The morbimortality rate for the procedure was 18%. PMID:20584469

  14. Endovascular and microsurgical treatment of cerebral arteriovenous malformations: Current recommendations

    PubMed Central

    Conger, Andrew; Kulwin, Charles; Lawton, Michael T.; Cohen-Gadol, Aaron A.

    2015-01-01

    Background: Cerebral arteriovenous malformations (AVMs) can be a heterogeneous pathological entity whose management requires a complex decision-making process due to the risks associated with their treatment and natural history. Despite the recently published conclusions of the aborted Randomized Trial of Brain Unruptured AVMs (ARUBA) trial, the authors of this article believe multimodality intervention in general and microsurgical resection in particular continue to play a major role in the management of carefully selected ruptured or unruptured AVMs. Methods: The authors provide an overview of their methodology for endovascular intervention and microsurgical resection and share their technical nuances for successful embolization and microsurgical resection of AVMs with special emphasis on complication avoidance. Results: The authors have achieved successful outcomes in embolization and resection of cerebral AVMs when using their methodology. Conclusions: These lesions are among the most technically difficult pathological entities handled by the cerebrovascular specialist, and an overview of technical concepts to help systematize this challenging and variable endeavor can improve the safety of their treatment. PMID:25883831

  15. Endovascular Treatment of Isolated Dissection of Superior Mesenteric Artery.

    PubMed

    Sirignano, P; Setacci, F; Galzerano, G; Setacci, C

    2015-01-01

    Isolated spontaneous dissection of the superior mesenteric artery is extremely rare. In December 2012, a 45-year-old man, without significant comorbidities, presented at the emergency room of another hospital with abdominal pain. The patient was treated with medical therapy and discharged on resolution of the pain. Three months later he returned to the emergency room with a new onset of pain. CT-angiography (CTA) showed an isolated SMA dissection associated with aneurysmal dilatation. The patient was referred to our attention. We attempted endovascular exclusion of the dissecting aneurysm in May 2013. We deployed a self-expandable nitinol stent (BostonSC Adapt 4-9×32 mm) in order to simultaneously repair the dissection, preserve the branches and exclude the aneurysm. Postoperative course was uneventful and the patient was discharged on postoperative day 2. At 10-month follow-up CTA showed excellent positioning of the stent, patency of the visceral branches and shrinkage of the aneurysm. PMID:26324038

  16. Endovascular Embolization of Spontaneous Retroperitoneal Hemorrhage Secondary to Anticoagulant Treatment

    SciTech Connect

    Isokangas, Juha-Matti Peraelae, Jukka M.

    2004-11-15

    The purpose of this study was to report a single hospital's experience of endovascular treatment of patients with retroperitoneal hemorrhage (RPH) secondary to anticoagulant treatment. Ten consecutive patients treated in an intensive care unit and needing blood transfusions due to RPH secondary to anticoagulation were referred for digital subtraction angiography (DSA) to detect the bleeding site(s) and to evaluate the possibilities of treating them by transcatheter embolization. DSA revealed bleeding site(s) in all 10 patients: 1 lumbar artery in 4 patients, 1 branch of internal iliac artery in 3 patients and multiple bleeding sites in 3 patients. Embolization could be performed in 9 of them. Coils, gelatin and/or polyvinyl alcohol were used as embolic agents. Bleeding stopped or markedly decreased after embolization in 8 of the 9 (89%) patients. Four patients were operated on prior to embolization, but surgery failed to control the bleeding in any of these cases. Abdominal compartment syndrome requiring surgical or radiological intervention after embolization developed in 5 patients. One patient died, and 2 had sequelae due to RPH. All 7 patients whose bleeding stopped after embolization had a good clinical outcome. Embolization seems to be an effective and safe method to control the bleeding in patients with RPH secondary to anticoagulant treatment when conservative treatment is insufficient.

  17. Novel nanofiber-based material for endovascular scaffolds.

    PubMed

    Wang, Rui; Levi-Polyanchenko, Nicole; Morykwas, Michael; Argenta, Louis; Wagner, William D

    2015-03-01

    Conventional collagen-based heart valves eventually fail because of insufficient replacement of graft material by host tissue. In this study, type I collagen was blended with silk fibroin and the synthetic elastic polymer poly (glycerol-sebacate) (PGS) in varying proportions to create multifunctional electrospun nanofibrous materials tailored for use as endovascular scaffolds such as heart valve replacement. Depending on the blended material the elastic moduli ranged from 2.3 to 5.0 Mpa; tensile stresses ranged from 0.8 to 1.5 Mpa; and strains ranged from 30% to 70%. Electrospun materials with a weight ratio of 4.5:4.5:1 (collagen, fibroin, and PGS) (termed PFC mats) were the most similar to native heart valves. In vitro degradation of PFC mats was 0.01% per week. Endothelial cells adhered to, proliferated, and formed cell-cell junctions on PFC mats. Compared with collagen hydrogels and electrospun collagen mats respectively 220-290% less platelet adhesion was observed for PFC mats. The study demonstrates that PFC material has superior mechanical properties, low degradation, and reduced thrombogenic potential and suggests that further investigation of this biomaterial for cardiovascular applications is warranted. PMID:25044469

  18. Endovascular Renal Artery Denervation: Why, When, and How?

    SciTech Connect

    Sapoval, Marc; Azizi, Michel; Bobrie, Guillaume; Cholley, Bernard; Pagny, Jean-Yves; Plouin, Pierre-Francois

    2012-06-15

    Endovascular renal artery denervation (ERAD) is a new procedure to reduce renal and systemic sympathetic overactivity in hypertensive patients. The role of sympathetic overactivity is recognized since a long time as being one the contributor of human hypertension. In support of this view, several studies in experimental models of hypertension in animal as well as hypertensive human subjects have demonstrated that sympathetic overactivity plays a central role in hypertension catheter based renal denervation is now possible, and this procedure may provide a useful adjunct for the management of patients with drug-resistant primary hypertension. Following a cohort study, the results of an open label randomized control trial have been published showing very encouraging results. The purpose of this paper is to help interventionalists to better understand the medical and technical issues related to this new intervention. It is most likely that as underlined in a recent editorial several other technical approaches may appear in the future, however because this is the only technique that is available today, we will focus on radiofrequency based technique.

  19. Percutaneous Endovascular Treatment of Chronic Iliac Artery Occlusion

    SciTech Connect

    Carnevale, F. C. De Blas, Mariano; Merino, Santiago; Egana, Jose M.; Caldas, Jose G.M.P.

    2004-09-15

    Purpose: To evaluate the clinical and radiological long-term results of recanalization of chronic occluded iliac arteries with balloon angioplasty and stent placement.Methods: Sixty-nine occluded iliac arteries (mean length 8.1 cm; range 4-16 cm) in 67 patients were treated by percutaneous transluminal angioplasty and stent placement. Evaluations included clinical assesment according to Fontaine stages, Doppler examinations with ankle-brachial index (ABI) and bilateral lower extremity arteriograms. Wallstent and Cragg vascular stents were inserted for iliac artery recanalization under local anesthesia. Follow-up lasted 1-83 months (mean 29.5 months).Results: Technical success rate was 97.1% (67 of 69). The mean ABI increased from 0.46 to 0.85 within 30 days after treatment and was 0.83 at the most recent follow-up. Mean hospitalization time was 2 days and major complications included arterial thrombosis (3%), arterial rupture (3%) and distal embolization (1%). During follow-up 6% stenosis and 9% thrombosis of the stents were observed. Clinical improvement occurred in 92% of patients. Primary and secondary patency rates were 75% and 95%, respectively.Conclusion: The long-term patency rates and clinical benefits suggest that percutaneous endovascular revascularization with metallic stents is a safe and effective treatment for patients with chronic iliac artery occlusion.

  20. Beta dosimetry with microMOSFETs for endovascular brachytherapy

    NASA Astrophysics Data System (ADS)

    Drud, Eva; Todorovic, Manuel; Schönborn, Thies; Schmidt, Rainer

    2006-12-01

    The aim of this study was to investigate if microMOSFETs are suitable for the dosimetry and quality assurance of beta sources. The microMOSFET dosimeters have been tested for their angular dependence in a 6 MeV electron beam. The dose rate dependence was measured with an iridium-192 afterloading source. By varying the source-to-surface distance (SSD) in a 12 MeV electron beam the dose rate dependence in an electron beam was also investigated. To measure a depth dose curve the dose rate at 2, 5, 8 and 12 mm distance from the beta source train axis was determined with the OPTIDOS and the microMOSFET detector. A comparison between the two detector types shows that the microMOSFET is suitable for quality assurance of beta sources for endovascular brachytherapy (EVBT). The homogeneity of the source is checked by measurements at five points (for the 60 mm source at 10, 20, 30, 40 and 50 mm) along the source train. The microMOSFET was then used to evaluate the influence of a common stent type (single layer stainless steel) on the dose distribution in water. The stent led to a dose inhomogeneity of ±8.5%. Additionally the percentage depth dose curves with and without a stent were compared. The depth dose curves show good agreement which means that the stent does not change the beta spectrum significantly.

  1. Endovascular Treatment of Thoracic Aortic Dissection: Hemodynamic Shear Stress Study

    NASA Astrophysics Data System (ADS)

    Tang, Yik Sau; Lai, Siu Kai; Cheng, Stephen Wing Keung; Chow, Kwok Wing

    2012-11-01

    Thoracic Aortic Dissection (TAD), a life threatening cardiovascular disease, occurs when blood intrudes into the layers of the aortic wall, creating a new artificial channel (the false lumen) beside the original true lumen. The weakened false lumen wall may expand, enhancing the risk of rupture and resulting in high mortality. Endovascular treatment involves the deployment of a stent graft into the aorta, thus blocking blood from entering the false lumen. Due to the irregular geometry of the aorta, the stent graft, however, may fail to conform to the vessel curvature, and would create a ``bird-beak'' configuration, a wedge-shaped domain between the graft and the vessel wall. Computational fluid dynamics analysis is employed to study the hemodynamics of this pathological condition. With the `beaking' configuration, the local hemodynamic shear stress will drop below the threshold of safety reported earlier in the literature. The oscillating behavior of the shear stress might lead to local inflammation, atherosclerosis and other undesirable consequences. Supported by the Innovation and Technology Fund of the Hong Kong Government.

  2. Bare Metal Stenting for Endovascular Exclusion of Aortic Arch Thrombi

    SciTech Connect

    Mahnken, Andreas H.; Hoffman, Andras; Autschbach, Ruediger; Damberg, Anneke L. M.

    2013-08-01

    BackgroundAortic thrombi in the ascending aorta or aortic arch are rare but are associated with a relevant risk of major stroke or distal embolization. Although stent grafting is commonly used as a treatment option in the descending aorta, only a few case reports discuss stenting of the aortic arch for the treatment of a thrombus. The use of bare metal stents in this setting has not yet been described.MethodsWe report two cases of ascending and aortic arch thrombus that were treated by covering the thrombus with an uncovered stent. Both procedures were performed under local anesthesia via a femoral approach. A femoral cutdown was used in one case, and a total percutaneous insertion was possible in the second case.ResultsBoth procedures were successfully performed without any periprocedural complications. Postoperative recovery was uneventful. In both cases, no late complications or recurrent embolization occurred at midterm follow-up, and control CT angiography at 1 respectively 10 months revealed no stent migration, freely perfused supra-aortic branches, and no thrombus recurrence.ConclusionTreating symptomatic thrombi in the ascending aorta or aortic arch with a bare metal stent is feasible. This technique could constitute a minimally invasive alternative to a surgical intervention or complex endovascular therapy with fenestrated or branched stent grafts.

  3. Endovascular Treatment of Chronic Mesenteric Ischemia: Results in 14 Patients

    SciTech Connect

    Chahid, Tamam; Alfidja, Agaicha T.; Biard, Marie; Ravel, Anne; Garcier, Jean Marc; Boyer, L.

    2004-11-15

    We evaluated immediate and long-term results of percutaneous transluminal angioplasty (PTA) and stent placement to treat stenotic and occluded arteries in patients with chronic mesenteric ischemia. Fourteen patients were treated by 3 exclusive celiac artery (CA) PTAs (2 stentings), 3 cases with both Superior Mesenteric Artery (SMA) and CA angioplasties, and 8 exclusive SMA angioplasties (3 stentings). Eleven patients had atheromatous stenoses with one case of an early onset atheroma in an HIV patient with antiphospholipid syndrome. The other etiologies of mesenteric arterial lesions were Takayashu arteritis (2 cases) and a postradiation stenoses (1 case). Technical success was achieved in all cases. Two major complications were observed: one hematoma and one false aneurysm occurring at the brachial puncture site (14.3%). An immediate clinical success was obtained in all patients. During a follow-up of 1-83 months (mean: 29 months), 11 patients were symptom free; 3 patients had recurrent pain; in one patient with inflammatory syndrome, pain relief was obtained with medical treatment; in 2 patients abdominal pain was due to restenosis 36 and 6 months after PTA, respectively. Restenosis was treated by PTA (postirradiation stenosis), and by surgical bypass (atheromatous stenosis). Percutaneous endovascular techniques are safe and accurate. They are an alternative to surgery in patients with chronic mesenteric ischemia due to short and proximal occlusive lesions of SMA and CA.

  4. Endovascular Stent Placement for Hemodialysis Arteriovenous Access Stenosis

    PubMed Central

    Neuen, Brendon L.; Baer, Richard A.; Grainer, Frank; Mantha, Murty L.

    2015-01-01

    This study aims to report the outcomes of nitinol and polytetrafluoroethylene covered stent placement to treat hemodialysis arteriovenous access stenosis at a single center over a five-year period. Clinical and radiological information was reviewed retrospectively. Poststent primary and secondary patency rates were determined using Kaplan-Meier analysis. Ten clinical variables were subjected to multivariate Cox regression analysis to determine predictors of patency after stent placement. During the study period 60 stents were deployed in 45 patients, with a mean follow-up of 24.5 months. The clinical and anatomical success rate was 98.3% (59/60). Poststent primary patency rates at 6, 12, and 24 months were 64%, 46%, and 35%, respectively. Poststent secondary patency rates at 6, 12, and 24 months were 95%, 89%, and 85%, respectively. Stent placement for upper arm lesions and in access less than 12 months of age was associated with reduced primary patency (adjusted hazards ratio [HR] 5.1, p = 0.0084, and HR 3.5, p = 0.0029, resp.). Resistant or recurrent stenosis can be successfully treated by endovascular stent placement with durable long-term patency, although multiple procedures are often required. Stent placement for upper arm lesions and in arteriovenous access less than 12 months of age was associated with increased risk of patency loss. PMID:26649199

  5. Modeling of endovascular patch welding using the computer program LATIS

    SciTech Connect

    Glinsky, M.E.; London, R.A.; Zimmerman, G.B.; Jacques, S.L.

    1995-03-01

    A new computer program, LATIS, being developed at Lawrence Livermore National Laboratory is used to study the effect of pulsed laser irradiation on endovascular patch welding. Various physical and biophysical effects are included in these simulations: laser light scattering and absorption, tissue heating and heat conduction, vascular cooling, and tissue thermal damage. The geometry of a patch being held against the inner vessel wall (500 {mu}m inner diameter) by a balloon is considered. The system is exposed to light pulsed from an optical fiber inside the balloon. A minimum in the depth of damage into the vessel wall is found. The minimum damage zone is about the thickness of the patch material that is heated by the laser. The more ordered the tissue the thinner the minimum zone of damage. The pulse length which minimizes the zone of damage is found to be the time for energy to diffuse across the layer. The delay time between the pulses is determined by the time for the heated layer to cool down. An optimal pulse length exists which minimizes the total time needed to weld the patch to the wall while keeping the thickness of the damaged tissue to less than 100 {mu}m. For the case that is considered, a patch dyed with light absorbing ICG on the side next to the vessel (thickness of the dyed layer is 60 {mu}m), the best protocol is found to be 65-200 ms pulses applied over 2 min.

  6. Endovascular Treatment of Iatrogenic and Traumatic Carotid Artery Dissection

    SciTech Connect

    Schulte, Stefan; Donas, Konstantinos P. Pitoulias, Georgios A.; Horsch, Svante

    2008-09-15

    This paper reports on the early and midterm results of endovascular treatment of acute carotid artery dissections, its specific problems, and its limitations. We encountered seven patients with symptomatic extracranial carotid artery dissection, three cases of which occurred after carotid endarterectomy, two after carotid angioplasty and stenting, and two after trauma. Balloon-expandable and self-expanding stents were placed using a transfemoral approach. Success in restoring the carotid lumen was achieved in all patients. No procedure-related complications occurred. All patients experienced significant clinical improvement while in the hospital and achieved complete long-term recovery. At follow-up (mean, 22.4 months), good luminal patency of the stented segments was observed. In conclusion, in this small series, primary stent-supported angioplasty seems to be a safe and effective strategy in the treatment of selected patients having acute traumatic extracranial carotid artery dissection, with excellent early and midterm results. Larger series and longer-term follow-up are required before definitive recommendations can be made.

  7. New Endovascular Method for Transvascular Exit of Arteries and Veins: Developed in Simulator, in Rat and in Rabbit with Full Clinical Integration

    PubMed Central

    Lundberg, Johan; Jonsson, Stefan; Holmin, Staffan

    2010-01-01

    Background Endovascular technique has benefits vis-a-vis surgical access to organs with less accessible anatomical locations. To minimize surgical risk we propose a novel endovascular technique, to create parenchymal access through endovascular methods. Methodology/Principal Findings We have developed, manufactured and tested an endovascular catheter with a depth limiting collar and a penetrating tip that is used to perforate vessels, thereby creating a working channel to the extra-vascular space. Computer simulations and subsequent interventions have been performed ex vivo and in vivo in both small and large animals by testing different prototypes. All tests were designed for testing extravascular hemostasis and absence of thrombo-embolic complications when exiting the vessels from the inside to the extra vascular space. We have deposited prototypes after intervention in vascular walls over a period of 14 days in rat with no impairment on blood flow and no signs of thrombo-embolic complications upon re-exploration (n = 7). We have also incorporated the catheter system with clinically available systems both in an ex vivo simulator setting and in a full scale clinical angiographical setting in rabbit were no bleeding (0%) in any of the interventions performed (n = 40). To prevent hemorrhage during termination of the procedure, a hollow electrolysis detachment-zone leaves the distal tip in the vessel-wall after the intervention. This has also been tested with absolute hemostasis in large animals (n = 6). Conclusions/Significance We have developed and tested a new system for transvascular tissue access in simulations, ex vivo and in vivo in small and large animals, integrating it with standard clinical catheters and angiographical environment, with absolute hemostasis and without thromboembolic complications. In a clinical setting for stem cell transplantation, local substance administration or tissue sampling, the benefit should be greatest in organs that

  8. Successful Endovascular Treatment of Iliac Vein Compression (May-Thurner) Syndrome in a Pediatric Patient

    SciTech Connect

    Oguzkurt, Levent Tercan, Fahri; Sener, Mesut

    2006-06-15

    A 10-year-old boy presented to our clinic with left lower extremity swelling present for 1 year with deterioration of symptoms during the prior month. Laboratory investigation for deep vein thrombosis was negative. Venography and computed tomography scan of the pelvis showed compression of the left common iliac vein by the right common iliac artery. A diagnosis of iliac vein compression syndrome was made. After venography, endovascular treatment was planned. The stenosis did not respond to balloon dilatation and a 12 mm Wallstent was placed with successful outcome. The patient's symptoms improved but did not resolve completely, probably due to a chronically occluded left superficial femoral vein that did not respond to endovascular recanalization. To the best of our knowledge, this is the first case of successful endovascular treatment of iliac vein compression syndrome with stent placement in a pediatric patient.

  9. History, Evolution, and Importance of Emergency Endovascular Treatment of Acute Ischemic Stroke.

    PubMed

    Holodinsky, Jessalyn K; Yu, Amy Y X; Assis, Zarina A; Al Sultan, Abdulaziz S; Menon, Bijoy K; Demchuk, Andrew M; Goyal, Mayank; Hill, Michael D

    2016-05-01

    More than 800,000 people in North America suffer a stroke each year, with ischemic stroke making up the majority of these cases. The outcomes of ischemic stroke range from complete functional and cognitive recovery to severe disability and death; outcome is strongly associated with timely reperfusion treatment. Historically, ischemic stroke has been treated with intravenous thrombolytic agents with moderate success. However, five recently published positive trials have established the efficacy of endovascular treatment in acute ischemic stroke. In this review, we will discuss the history of stroke treatments moving from various intravenous thrombolytic drugs to intra-arterial thrombolysis, early mechanical thrombectomy devices, and finally modern endovascular devices. Early endovascular therapy failures, recent successes, and implications for current ischemic stroke management and future research directions are discussed. PMID:27021771

  10. Endovascular repair of an abdominal aortic aneurysm in the presence of a hydronephrotic horseshoe kidney.

    PubMed

    Krivoshei, Lian; Akin-Olugbade, Yemi; McWilliams, Glen; Halak, Moshe; Silverberg, Daniel

    2012-02-01

    The aim of this paper is to report an unusual case of a patient with an abdominal aortic aneurysm (AAA) and a hydronephrotic horseshoe kidney (HSK) that was repaired by endovascular means. An 81-year-old male patient with a known HSK was found to have hydronephrosis and an AAA. The patient's aneurysm was treated with an endovascular stent graft which required the covering of accessory renal arteries. He had an uneventful recovery with complete resolution of the hydronephrosis evident on a computed tomography scan performed seven months after the surgery. In conclusion, endovascular aneurysm repair is a feasible therapeutic option for an AAA coexisting with an HSK and may be considered as a valid alternative to open repair when concomitant hydronephrosis is present. PMID:22328622

  11. [A Case of Carotid Free-Floating Thrombus Treated by Carotid Ultrasonography-Guided Endovascular Approach].

    PubMed

    Otawa, Masato; Kinkori, Takeshi; Watanabe, Kenichi; Ando, Ryo; Tambara, Masao; Arima, Toru

    2016-06-01

    We experienced a case of carotid free-floating thrombus treated by carotid ultrasonography-guided endovascular approach. A 63-year-old man was brought to our hospital with the chief complaint of sudden onset left hemiplegia. MRI revealed acute infarction of the right MCA territory due to the right M1 occlusion. Carotid ultrasonography showed a pedunculated, polypoid mobile plaque floating with the cardiac beat. We attempted ultrasonography-guided endovascular treatment. Under proximal balloon protection, the floating plaque was successfully aspirated into the Penumbra aspiration catheter. Carotid stent was also placed to stabilize the residual pedicle of the plaque. Aspirated plaque was identified as fresh thrombus by pathological examination. Carotid ultrasonography-guided endovascular approach was effective for getting the picture of real-time dynamics of the carotid FFT. PMID:27270147

  12. Meta-Analysis of Local Endovascular Therapy for Acute Ischemic Stroke.

    PubMed

    Kennedy, Sean A; Baerlocher, Mark O; Baerlocher, Felix; Socko, Daniel; Sacks, David; Nikolic, Boris; Wojak, Joan C; Haskal, Ziv J

    2016-03-01

    A meta-analysis was performed to assess randomized controlled trials comparing local endovascular therapy (with and without intravenous thrombolysis) versus standard care (intravenous thrombolysis alone when appropriate) for acute ischemic stroke. Local endovascular therapy showed a significant improvement in functional independence versus standard care (odds ratio, 1.779; 95% confidence interval, 1.262-2.507; P < .001). This benefit strengthened further on subgroup analyses of trials in which a majority of cases used stent retrievers, trials with intravenous thrombolysis use in both arms when appropriate, and trials that required preprocedural imaging of all patients. There were no significant differences between arms in terms of mortality, hemicraniectomy, intracranial hemorrhage, and cerebral edema rates (P > .05). In conclusion, in the treatment of acute ischemic stroke, local endovascular therapy leads to improved functional independence compared with standard care. PMID:26803573

  13. Thoracic endovascular repair for acute type A aortic dissection: operative technique

    PubMed Central

    Shah, Aamir

    2016-01-01

    Acute type A aortic dissection is a potentially lethal condition which requires immediate diagnostic and therapeutic intervention. Open surgical repair remains the standard of care as survival rates continue to improve in the modern surgical era. Unfortunately, up to twenty percent of patients are denied surgical therapy because they are deemed medically unfit to undergo open repair. The application of thoracic endovascular aortic repair (TEVAR) has changed the treatment paradigm for aortic disease involving the descending thoracic aorta and may be a viable rescue option for patients with type A dissection who are not eligible for open surgical repair. New endovascular devices and advanced image-guided procedures are continually evolving. This article summarizes the pathology of aortic dissection and focuses on currently available endovascular solutions for transapical and transfemoral stent graft deployment for acute aortic dissection involving the ascending aorta for selected patients who are ineligible for open surgical repair. PMID:27563553

  14. Endovascular transarterial embolization of cerebral arteriovenous malformation with ethylene-vinyl alcohol copolymer.

    PubMed

    Tan, Lee A; Johnson, Andrew K; Keigher, Kiffon M; Moftakhar, Roham; Lopes, Demetrius K

    2014-07-01

    Cerebral arteriovenous malformations (AVMs) have an estimated 2-4% annual risk of hemorrhage. Treatment options for AVMs include microsurgical resection, stereotactic radiosurgery, and endovascular embolization. As endovascular technology and techniques continue to advance and mature, endovascular embolization is becoming an increasingly vital component of AVM treatment not only as a presurgical treatment to reduce microsurgical risks, but also as a stand-alone curative method in some cases. This case illustrates the successful and curative transarterial embolization of a right frontal AVM in a 17-year-old boy with ethylene-vinyl alcohol copolymer (Onyx). The video can be found here: http://youtu.be/L4hE1MvCZCY . PMID:24983727

  15. Thoracic endovascular repair for acute type A aortic dissection: operative technique.

    PubMed

    Shah, Aamir; Khoynezhad, Ali

    2016-07-01

    Acute type A aortic dissection is a potentially lethal condition which requires immediate diagnostic and therapeutic intervention. Open surgical repair remains the standard of care as survival rates continue to improve in the modern surgical era. Unfortunately, up to twenty percent of patients are denied surgical therapy because they are deemed medically unfit to undergo open repair. The application of thoracic endovascular aortic repair (TEVAR) has changed the treatment paradigm for aortic disease involving the descending thoracic aorta and may be a viable rescue option for patients with type A dissection who are not eligible for open surgical repair. New endovascular devices and advanced image-guided procedures are continually evolving. This article summarizes the pathology of aortic dissection and focuses on currently available endovascular solutions for transapical and transfemoral stent graft deployment for acute aortic dissection involving the ascending aorta for selected patients who are ineligible for open surgical repair. PMID:27563553

  16. [Combined Open and Endovascular Repair of Multiple Aortic Aneurysms due to Syphilitic Aortitis].

    PubMed

    Shima, Shotaro; Okamura, Kennichi; Morizumi, Sei; Kawata, Mitsuhiro; Suematsu, Yoshihiro

    2015-06-01

    The patient was a 69-year-old man who presented with low-grade fever and appetite loss. Thoracoabdominal computed tomography revealed multiple aneurysms in the distal arch and descending thoracic and infrarenal aortic regions combined with a right common iliac artery aneurysm. After endovascular stent grafting for a right iliac artery aneurysm, he underwent total arch replacement and open stent grafting for the descending thoracic aneurysms. Pathological microscopic examination revealed an inflammatory infiltrate within the adventitia and destruction of the elastic fibers in the media, which are classical features of syphilitic aortitis. Endovascular aneurysm repair is contraindicated in mycotic infected aneurysms. However, endovascular repair is useful for treating mycotic infected aneurysm, if multiple aneurysms have the possibility of rupture and a high risk of surgery. PMID:26066872

  17. Modified cyanobacteria

    DOEpatents

    Vermaas, Willem F J.

    2014-06-17

    Disclosed is a modified photoautotrophic bacterium comprising genes of interest that are modified in terms of their expression and/or coding region sequence, wherein modification of the genes of interest increases production of a desired product in the bacterium relative to the amount of the desired product production in a photoautotrophic bacterium that is not modified with respect to the genes of interest.

  18. Endovascular Aortic Aneurysm and Dissection Repair (EVAR) in Iran: Descriptive Midterm Follow-up Results

    PubMed Central

    Haji Zeinali, Ali Mohammad; Marzban, Mehrab; Zafarghandi, Mohammadreza; Shirzad, Mahmood; Shirani, Shapour; Mahmoodian, Roshanak; Sheikhvatan, Mehrdad; Lotfi-Tokaldany, Masoumeh

    2016-01-01

    Background: Endovascular repair of aorta in comparison to open surgery has a low early operative mortality rate, but its long-term results are uncertain. Objectives: The current study describes for the first time our initial four-year experience of elective endovascular aortic repair (EVAR) at Tehran heart center, the first and a major referral heart center in Iran, as a pioneer of EVAR in Iran. Patients and Methods: A total of 51 patients (46 men) who had the diagnosis of either an abdominal aortic aneurysm (AAA) (n = 36), thoracic aortic aneurysm (TAA) (n = 7), or thoracic aortic dissection (TAD) (n = 8) who had undergone EVAR by Medtronic stent grafts by our team between December 2006 and June 2009 were reviewed. Results: The rate of in-hospital aneurysm-related deaths in the group with AAA stood at 2.8% (one case), while there was no in-hospital mortality in the other groups. All patients were followed up for 13-18 months. The cumulative death rate in follow-up was nine cases from the total 51 cases (18%), out of which six cases were in the AAA group (four patients due to non-cardiac causes and two patients due to aneurysm-related causes), one case in the TAA group (following a severe hemoptysis), and two cases in the TAD group (following an expansion of dissection from re-entrance). The major event-free survival rate was 80.7% for endovascular repair of AAA, 85.7% for endovascular repair of TAA, and 65.6% for endovascular repair of TAD. Conclusion: The endovascular stent-graft repair of the abdominal and thoracic aortic aneurysm and aortic dissection had high technical success rates in tandem with low-rate early mortality and morbidity, short hospital stay, and acceptable mid-term free symptom survival among Iranian patients. PMID:27110330

  19. Current Status of Endovascular Treatment for Vasospasm following Subarachnoid Hemorrhage: Analysis of JR-NET2

    PubMed Central

    HAYASHI, Kentaro; HIRAO, Tomohito; SAKAI, Nobuyuki; NAGATA, Izumi

    2014-01-01

    Endovascular treatments are employed for cerebral vasospasm following subarachnoid hemorrhage, which is not responded to the medical treatments. However, the effect or complication of the treatments is not known well. Here, we analyzed the data of Japanese Registry of Neuroendovascular Therapy 2 (JRNET2) and revealed current status of the endovascular treatment for the cerebral vasospasm. JR-NET2 is conducted from January 1, 2007 to December 31, 2009. Information on the clinical status, imaging studies, treatment methods, the results of treatment, and status 30 days later were recorded. Totally 645 treatments for 480 patients (mean age, 59.4 years; 72.7% woman) were included. Factors related to the neurological improvement and treatment related complications were statistically analyzed. Treatments for ruptured cerebral aneurysm were direct surgery for 366 cases and endovascular treatment for 253 cases. The timing of the endovascular treatment for the cerebral vasospasm was within 3 hours in 209 cases, 3–6 hours in 158 cases, and more than 6 hours in 158 cases. Intra-arterial vasodilator was employed for the 495 cases and percutaneous transluminal angioplasty for 140 cases. Neurological improvement was observed in 372 cases and radiological improvement was seen in 623 cases. The treatment related complication occurred in 20 cases (3.1%), including 6 cases of intracranial hemorrhage, 5 cases of cerebral ischemia, a case of puncture site trouble, and 8 cases of others. Statistical analysis showed early treatment was related to the neurological improvement. Current status of endovascular treatment for cerebral vasospasm was revealed. Endovascular treatment was effective for vasospasm especially was performed early. PMID:24257541

  20. Advanced Age and Disease Predict Lack of Symptomatic Improvement after Endovascular Iliac Treatment in Male Veterans

    PubMed Central

    Assi, Roland; Brownson, Kirstyn E.; Hall, Michael R.; Kuwahara, Go; Vasilas, Penny; Dardik, Alan

    2015-01-01

    Background: Endovascular angioplasty and stent placement is currently the most frequent treatment for iliac artery occlusive disease. However, despite a successful endovascular procedure, some patients do not experience symptomatic improvement and satisfaction with their care. This study seeks to identify patient-related factors associated with lack of symptomatic improvement after endovascular iliac artery treatment in male veterans. Methods: Retrospective review of patients treated with endovascular methods for iliac artery occlusive disease between January 2008 and July 2012 at VA Connecticut Healthcare System. Symptomatic improvement on the first post-operative visit was evaluated, with bilateral treatments counted separately. Results: Sixty-two patients had 91 iliac arteries treated with angioplasty and stent placement. Forty-seven (52 percent) legs had critical limb ischemia, and 77 (85 percent) had at least two-vessel distal runoff. Angiographic success was 100 percent. Patient-reported symptomatic improvement at the first post-operative visit was 55 percent (50/91). Lack of symptomatic improvement correlated with older age (OR 1.09 [1.03-1.17], p = 0.008), presence of critical limb ischemia (OR 3.03 [1.09-8.65], p = 0.034), and need for additional surgical intervention (OR 5.61 [1.65-17.36], p = 0.006). Survival, primary and secondary patency, and freedom from restenosis were comparable between patients who reported symptomatic improvement and those who did not. Conclusions: Despite angiographically successful revascularization, patients who are older or have critical limb ischemia who are treated with isolated endovascular iliac artery intervention are more likely to require additional interventions and less likely to experience symptomatic improvement. These patients may need more extensive infra-inguinal revascularization than isolated iliac angioplasty and stent placement, despite a preserved ankle-brachial index. Quality of life needs to be measured

  1. Endovascular aortic aneurysm repair with chimney and snorkel grafts: indications, techniques and results.

    PubMed

    Patel, Rakesh P; Katsargyris, Athanasios; Verhoeven, Eric L G; Adam, Donald J; Hardman, John A

    2013-12-01

    The chimney technique in endovascular aortic aneurysm repair (Ch-EVAR) involves placement of a stent or stent-graft parallel to the main aortic stent-graft to extend the proximal or distal sealing zone while maintaining side branch patency. Ch-EVAR can facilitate endovascular repair of juxtarenal and aortic arch pathology using available standard aortic stent-grafts, therefore, eliminating the manufacturing delays required for customised fenestrated and branched stent-grafts. Several case series have demonstrated the feasibility of Ch-EVAR both in acute and elective cases with good early results. This review discusses indications, technique, and the current available clinical data on Ch-EVAR. PMID:23674274

  2. Endovascular Treatment of Totally Occluded Superior Mesenteric Artery by Retrograde Crossing via the Villemin Arcade

    SciTech Connect

    Ferro, Carlo; Rossi, Umberto G. Seitun, Sara; Bovio, Giulio; Fornaro, Rosario

    2013-06-15

    Chronic mesenteric ischemia (CMI) is a rare disorder that is commonly caused by progressive atherosclerotic stenosis or occlusion of one or more mesenteric arteries. Endovascular treatment for symptomatic CMI represents a viable option, especially in high-operative risk patients. We report a case of acute symptomatic CMI with chronic totally occlusion of the superior mesenteric artery (SMA) associated with significant stenosis of celiac trunk (CT) and inferior mesenteric artery (IMA) that underwent endovascular treatment of all the three mesenteric arteries: stenting of CT and IMA stenosis, and recanalization of the SMA occlusion by retrograde crossing via the Villemin arcade.

  3. Hypertensive heart failure associated with middle aortic syndrome reversed dramatically by endovascular management.

    PubMed

    Kim, Weon; Park, Chung Su; Kim, Hee Jong; Kim, Kyung Hwan; An, Hye Mi; Kim, Yeon Hwa; Lim, Chur Hoan; Kang, Won Yu; Hwang, Sun Ho; Kim, Wan

    2011-09-01

    A 42-year-old male patient presented with refractory hypertension and congestive heart failure. He had taken hydrochlorthiazide 50 mg, carvedilol 25 mg, diltiazem 180 mg, and losartan 100 mg per day. Aortogram revealed a severe luminal narrowing in the distal thoracic aorta with a peak systolic pressure gradient of 60 mmHg across the lesion. Endovascular management was performed with 22 × 80 mm self-expandable Nitinol-S stent after predilation with 10 × 40 mm balloon. After endovascular management, the patient's blood pressure, left ventricular ejection fraction (LVEF) and dilated LV dimension were remarkably improved. PMID:22073325

  4. Endovascular Interventions for Idiopathic Intracranial Hypertension and Venous Tinnitus: New Horizons.

    PubMed

    Hui, Ferdinand K; Abruzzo, Todd; Ansari, Sameer A

    2016-05-01

    Pulsatile tinnitus from intracranial venous abnormalities is an uncommon cause of pulse synchronous tinnitus. Endovascular therapies may have applications in many of these disease conditions. They have the advantage of being minimally invasive and may selectively eliminate the site of turbulence. Venous stenting has been used successfully to treat venous stenoses with low complication rates and high success rates in patients with idiopathic intracranial hypertension though randomized controlled data are lacking. Careful exclusion of other causes of tinnitus should be performed before consideration for surgical or endovascular treatment of presumed causative lesions of venous tinnitus. PMID:27154610

  5. Endovascular Coiling of Aneurysm Remnants after Clipping in Patients with Follow-up

    PubMed Central

    Mangiafico, S.; Cellerini, M.; Villa, G.; Ammannati, F.; Paoli, L.; Mennonna, P.

    2005-01-01

    Summary The vast majority of intracranial aneurysms can be obliterated completely with surgical clipping. However, postoperative remnants occur in about 4 to 8% of patients who undergo postoperative angiography. Endovascular embolization has been successfully performed in patients with postoperative aneurysm remnant and it may represent a therapeutic alternative to surgical reintervention. Twelve aneurysm remnants after surgical clipping were treated with endovascular embolization using GDC. All aneurysms were located in the anterior circulation. Our experience confirms the feasibility and relative safety of this treatment strategy that may be considered a valid alternative to reintervention. PMID:20584434

  6. Update on New Tools for Three-dimensional Navigation in Endovascular Procedures

    PubMed Central

    van den Berg, Jos C.

    2014-01-01

    Three-dimensional (3D) guidance for endovascular procedures has developed over the last decade from 3D rotational angiography to the use of dynamic 3D roadmap techniques. The latest development is image merging. This technique combines real-time feedback of fluoroscopy with optimal soft-tissue contrast of previously performed computed tomography (CT) or magnetic resonance angiography. Merging of CT angiography and cone-beam CT/fluoroscopic images is feasible, and preliminary results look promising. Merging will allow us to further reduce radiation exposure, contrast dose, and procedural time, and its main use and benefit will be in complex endovascular interventions. PMID:26798746

  7. Endovascular management of an acquired aortobronchial fistula following aortic bypass for coarctation

    PubMed Central

    O’Sullivan, Katie E.; Bolster, Ferdia; Lawler, Leo P.; Hurley, John

    2014-01-01

    Aortobronchial fistula (ABF) in the setting of aortic coarctation repair is very rare but uniformly fatal if untreated. Endovascular stenting of the descending aorta is now the first-choice approach for ABF presenting with haemoptysis and offers a less-invasive technique with improved outcomes, compared with open repair. We report a case of late ABF occurring following bypass for aortic coarctation. Management focused on two key manoeuvres: use of a covered endovascular stent to occlude the aortic bypass thus controlling the fistula and dilatation and stenting of native coarctation. PMID:24057860

  8. Internal iliac artery aneurysmo-colonic fistula after endovascular stent-graft repair: a case report.

    PubMed

    Yanase, Yohsuke; Fukada, Johji; Tamiya, Yukihiko

    2015-01-01

    We describe rare ilio-enteric fistula that developed after endovascular repair of a left internal iliac artery aneurysm (IIAA). An 83-year-old man with a history of previous surgeries via laparotomies suddenly developed a high fever 3 years after undergoing endovascular abdominal aortic repair (EVAR) with a stent-graft to treat a left isolated IIAA. Computed tomography imaging revealed a fistula between the IIAA and the sigmoid colon. A colostomy was created because severe intraperitoneal adhesions prevented resection of the IIAA. The postoperative course was uneventful and the patient remained free of infection without antibiotics. Residual aneurysms can cause complications after EVAR. PMID:25848433

  9. Internal Iliac Artery Aneurysmo–Colonic Fistula after Endovascular Stent-Graft Repair: A Case Report

    PubMed Central

    Fukada, Johji; Tamiya, Yukihiko

    2015-01-01

    We describe rare ilio-enteric fistula that developed after endovascular repair of a left internal iliac artery aneurysm (IIAA). An 83-year-old man with a history of previous surgeries via laparotomies suddenly developed a high fever 3 years after undergoing endovascular abdominal aortic repair (EVAR) with a stent-graft to treat a left isolated IIAA. Computed tomography imaging revealed a fistula between the IIAA and the sigmoid colon. A colostomy was created because severe intraperitoneal adhesions prevented resection of the IIAA. The postoperative course was uneventful and the patient remained free of infection without antibiotics. Residual aneurysms can cause complications after EVAR. PMID:25848433

  10. Successful Endovascular Repair of Ruptured Abdominal Aortic Aneurysm in a Renal Transplant Recipient

    SciTech Connect

    Kaskarelis, Ioannis S. Koukoulaki, Maria; Lappas, Ioannis; Karkatzia, Fani; Dimopoulos, Nikitas; Filias, Vasilios; Bellenis, Ion; Vougas, Vasilios; Drakopoulos, Spiros

    2006-04-15

    A renal transplant recipient presented in the early post-transplantation period with rupture of an abdominal aortic aneurysm. The high mortality rate of the surgical repair of ruptured aneurysm in addition to the concern of preserving the renal graft prompted us to seek alternative approaches, such as repairing the aneurysm by means of endovascular techniques. The ruptured aneurysm was confirmed by performing computed tomography and digital angiography and thereafter was successfully repaired by endovascular stenting technique (Talent stent-graft), which seems to be a safe and effective method of preserving a renal graft.

  11. Endovascular Treatment for Proximal Anastomotic Pseudoaneurysm after Total Arch Replacement in Behcet's Disease.

    PubMed

    Sakata, Tomoki; Ueda, Hideki; Watanabe, Michiko; Kohno, Hiroki; Tamura, Yusaku; Abe, Shinichiro; Inage, Yuichi; Ikeuchi, Hiroki; Kanda, Tomoyoshi; Fujii, Masahiko; Matsumiya, Goro

    2016-07-01

    A 17-year-old patient underwent total arch replacement for aortic arch aneurysm due to vascular Behcet's disease (BD). Follow-up computed tomography, performed 6 months after the operation, demonstrated pseudoaneurysm formation at the proximal anastomotic site. We performed endovascular treatment and used a short stent graft that was originally designed for abdominal aortic aneurysm. To avoid the occlusion of the coronary or brachiocephalic artery (BCA) due to stent graft migration, we used right ventricular rapid pacing and BCA ballooning. Thus, we believe that endovascular treatment can be used for anastomotic complications in the ascending aorta after open surgery for connective tissue disorders including BD. PMID:27174345

  12. Multiple multilayer stents for thoracoabdominal aortic aneurysm: a possible new tool for aortic endovascular surgery

    PubMed Central

    Tolva, Valerio Stefano; Bianchi, Paolo Guy; Cireni, Lea Valeria; Lombardo, Alma; Keller, Guido Carlo; Parati, Gianfranco; Casana, Renato Maria

    2012-01-01

    Purpose Endovascular surgery data are confirming the paramount role of modern endovascular tools for a safe and sure exclusion of thoracoabdominal lesions. Case report A 57-year-old female presented with severe comorbidity affected by a 58 mm thoracoabdominal aortic aneurysm (TAAA). After patient-informed consent and local Ethical Committee and Italian Public Health Ministry authorization, three multilayer stents were implanted in the thoracoabdominal aortic tract, obtaining at a 20-month computed tomography scan follow up, a complete exclusion of the TAAA, with normal patency of visceral vessels. Conclusion Multilayer stents can be used in thoracoabdominal aortic aneurysm, with positive results. PMID:22866014

  13. Endovascular Repair of an Anastomotic Leak Following Open Repair of Abdominal Aortic Aneurysm

    SciTech Connect

    Mofidi, R. Flett, M.; Milne, A.; Chakraverty, S.

    2007-09-15

    This report describes the case of an early postoperative anastomotic leak following elective open repair of an infrarenal abdominal aortic aneurysm which was successfully treated by endovascular stent-grafting. A 71-year-old man underwent open tube graft repair of abdominal aortic aneurysm. Twelve days later he presented with a contained leak from the distal anastomosis, which was confirmed on CT scan. This was successfully treated with a bifurcated aortic stent-graft. This case illustrates the usefulness of the endovascular approach for resolving this rare surgical complication of open repair of abdominal aortic aneurysm and the challenges associated with the deployment of such a device within an aortic tube graft.

  14. Endovascular Aortic Aneurysm Repair with Chimney and Snorkel Grafts: Indications, Techniques and Results

    SciTech Connect

    Patel, Rakesh P.; Katsargyris, Athanasios Verhoeven, Eric L. G.; Adam, Donald J.; Hardman, John A.

    2013-12-15

    The chimney technique in endovascular aortic aneurysm repair (Ch-EVAR) involves placement of a stent or stent-graft parallel to the main aortic stent-graft to extend the proximal or distal sealing zone while maintaining side branch patency. Ch-EVAR can facilitate endovascular repair of juxtarenal and aortic arch pathology using available standard aortic stent-grafts, therefore, eliminating the manufacturing delays required for customised fenestrated and branched stent-grafts. Several case series have demonstrated the feasibility of Ch-EVAR both in acute and elective cases with good early results. This review discusses indications, technique, and the current available clinical data on Ch-EVAR.

  15. Ventricular Tract Hemorrhage Following Intracranial Nail Removal: Utility of Real-time Endovascular Assistance

    PubMed Central

    Rennert, Robert C.; Steinberg, Jeffrey A.; Sack, Jayson; Pannell, J. Scott; Khalessi, Alexander A.

    2016-01-01

    Penetrating brain trauma commonly results in occult neurovascular injury. Detailed cerebrovascular imaging can evaluate the relationship of intracranial foreign bodies to major vascular structures, assess for traumatic pseudoaneurysms, and ensure hemostasis during surgical removal. We report a case of a self-inflicted intracranial nail gun injury causing a communicating ventricular tract hemorrhage upon removal, as well as a delayed pseudoaneurysm. Pre- and post-operative vascular imaging, as well as intra-operative endovascular assistance, was critical to successful foreign body removal in this patient. This report demonstrates the utility of endovascular techniques for the assessment and treatment of occult cerebrovascular injuries from intracranial foreign bodies. PMID:27471490

  16. Endovascular Treatment of a Vertebral Artery Pseudoaneurysm Following Posterior C1-C2 Transarticular Screw Fixation

    SciTech Connect

    Mendez, Jose C. Gonzalez-Llanos, Francisco

    2005-01-15

    We present a case of vertebral artery pseudoaneurysm after a posterior C1-C2 transarticular screw fixation procedure that was effectively treated with endovascular coil occlusion. Vertebral artery pseudoaneurysm complicating posterior C1-C2 transarticular fixation is extremely rare, with only one previous case having been reported previously. Endovascular occlusion is better achieved in the subacute phase of the pseudoaneurysm, when the wall of the pseudoaneurysm has matured and stabilized. Further follow-up angiographies are mandatory in order to confirm that there is no recurrence of the lesion.

  17. Ventricular Tract Hemorrhage Following Intracranial Nail Removal: Utility of Real-time Endovascular Assistance.

    PubMed

    Rennert, Robert C; Steinberg, Jeffrey A; Sack, Jayson; Pannell, J Scott; Khalessi, Alexander A

    2016-01-01

    Penetrating brain trauma commonly results in occult neurovascular injury. Detailed cerebrovascular imaging can evaluate the relationship of intracranial foreign bodies to major vascular structures, assess for traumatic pseudoaneurysms, and ensure hemostasis during surgical removal. We report a case of a self-inflicted intracranial nail gun injury causing a communicating ventricular tract hemorrhage upon removal, as well as a delayed pseudoaneurysm. Pre- and post-operative vascular imaging, as well as intra-operative endovascular assistance, was critical to successful foreign body removal in this patient. This report demonstrates the utility of endovascular techniques for the assessment and treatment of occult cerebrovascular injuries from intracranial foreign bodies. PMID:27471490

  18. Endovascular parent artery occlusion of proximal posterior cerebral artery aneurysms: a report of two cases.

    PubMed

    Oishi, Hidenori; Tanoue, Shunsuke; Teranishi, Kosuke; Hasegawa, Hiroshi; Nonaka, Senshu; Magami, Shunsuke; Yamamoto, Munetaka; Arai, Hajime

    2016-06-01

    We report two cases of proximal posterior cerebral artery (PCA) aneurysms treated with endovascular parent artery occlusion (PAO) with coils. In both cases, selective injection from the 4 F distal access catheter clearly showed the perforating arteries arising from the PCA. Case No 1, a 49-year-old woman, was successfully treated with preservation of a paramedian artery. Case No 2, a 54-year-old woman, was treated in the same manner. The patient underwent extensive thalamic infarction after the procedure because of paramedian artery occlusion. Endovascular PAO with coils is feasible for proximal PCA aneurysms; however, preservation of perforating arteries arising from the PCA is mandatory. PMID:25969452

  19. Endovascular Interventions in Acute Ischemic Stroke: Recent Evidence, Current Challenges, and Future Prospects.

    PubMed

    Appireddy, Ramana; Zerna, Charlotte; Menon, Bijoy K; Goyal, Mayank

    2016-07-01

    After many years of clinical research, endovascular thrombectomy has been conclusively proven to be an effective treatment in acute ischemic stroke. The evidence is compelling; however, it is generated in high volume stroke centers with stroke expertise. Challenges remain ahead on translating and implementing this evidence in routine clinical care across the world. The current evidence has opened up avenues for further research and innovation in this field. In this review, we will discuss the evolution of evidence on endovascular thrombectomy followed by a discussion of challenges and future prospects in this exciting field of stroke care. PMID:27221502

  20. Hybrid Thoracic Endovascular Aortic Repair for Intercostal Patch Aneurysm after Thoracoabdominal Aortic Replacement

    PubMed Central

    Yoshitake, Akihiro; Hachiya, Takashi; Okamoto, Kazuma; Hirano, Akinori; Kasai, Mio; Akamatsu, Yuta; Oka, Hidetoshi; Shimizu, Hideyuki

    2015-01-01

    We report a case of hybrid thoracic endovascular aortic repair for intercostal patch aneurysm after thoracoabdominal aortic replacement. Eighteen years ago, a 63-year-old woman with Marfan syndrome had undergone thoracoabdominal aortic replacement with reimplantation of the intercostal artery in an island fashion. Follow-up computed tomography (CT) revealed a remaining intercostal patch aneurysm of diameter 60 mm 17 years after the last operation. Hybrid thoracic endovascular aortic repair for exclusion of this intercostal patch aneurysm was successfully performed, with visceral artery bypasses. Postoperative CT showed no anastomotic stenosis or endoleak. PMID:26730265