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Sample records for flow modifying endovascular

  1. Endovascular blood flow measurement system

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

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

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

    NASA Astrophysics Data System (ADS)

    Sherman, J. R.; Rangwala, H. S.; Ionita, C. N.; Dohatcu, A. C.; Lee, J. W.; Bednarek, D. R.; Hoffmann, K. R.; Rudin, S.

    2008-03-01

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

  3. Modified cuffed anastomosis technique to treat pseudoaneurysms following thoracic endovascular aortic repair

    PubMed Central

    Matsuo, Satoshi; Oda, Katsuhiko; Motoyoshi, Naotaka; Saiki, Yoshikatsu

    2012-01-01

    Pseudoaneurysm after thoracic endovascular aortic repair (TEVAR) is very rare. We report a case of thoracic aortic pseudoaneurysms due to flares at the proximal end of a stent graft after TEVAR for ductal aneurysm. We describe a total aortic arch replacement in this case using a modified cuffed anastomosis technique with an elephant trunk procedure leaving the partial stent graft in situ. PMID:22314008

  4. 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

  5. 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

  6. The Silk flow-diverter stent for endovascular treatment of intracranial aneurysms.

    PubMed

    Alghamdi, Faisal; Morais, Ricardo; Scillia, Pietro; Lubicz, Boris

    2015-01-01

    Flow diverter (FD) stents represent a new endovascular technique developed for the treatment of complex intracranial aneurysms (wide neck, fusiform, large, and giant aneurysms) that are challenging for classic endovascular techniques such as coiling, balloon-assisted coiling and stent-assisted coiling. Low porosity, high metal coverage, and high pore density are the main properties of FD stents. These properties induce hemodynamic changes redirecting the blood flow away from the aneurysm and into the parent artery leading to gradual thrombosis of the aneurysm. FD stents also provide scaffolding for subsequent neoendothelial proliferation, and vessel wall remodeling. This is considered as a paradigm shift compared to prior endovascular methods, which predominantly aimed at providing treatment inside the aneurysmal sac. This paper describes in detail the first released FD stent, the Silk flow-diverter stent (Balt Extrusion, Montmorency, France), its mechanism of action and deployment technique. It reviews the pertinent literature regarding safety, efficacy and potential risks and complications associated with the use of this stent.

  7. Endovascular stenting of an extracranial–intracranial saphenous vein high-flow bypass graft: Technical case report

    PubMed Central

    Maselli, Giuliano; Tommasi, Claudio De; Ricci, Alessandro; Gallucci, Massimo; Galzio, Renato J.

    2011-01-01

    Background: The authors describe a case of endovascular stenting of an extracranial–intracranial saphenous vein high-flow bypass graft in the management of a complex bilateral carotid aneurysm case. Case Description: A 43-year-old woman was admitted with progressive visual field restriction and headache. Imaging studies revealed bilateral supraclinoid carotid aneurysms. The right carotid aneurysm was clipped and the left one was treated by an endovascular procedure, after performing an internal carotid artery–middle cerebral artery (ICA-MCA) saphenous vein bypass graft. A few months following the bypass procedure, a 70–80% stenosis of the graft was discovered and treated endovascularly with a stenting procedure. Follow-up at 36 months after the first operation showed the patency of the venous graft and no neurological deficits. Conclusions: Endovascular stenting of the extracranial–intracranial saphenous vein high-flow bypass graft is technically feasible when postoperative graft occlusion is discovered. PMID:21660272

  8. Hemodynamic impact of cerebral aneurysm endovascular treatment devices: coils and flow diverters.

    PubMed

    Goubergrits, Leonid; Schaller, Jens; Kertzscher, Ulrich; Woelken, Thies; Ringelstein, Moritz; Spuler, Andreas

    2014-07-01

    Coils and flow diverters or stents are devices successfully used to treat cerebral aneurysms. Treatment aims to reduce intra-aneurysmal flow, thereby separating the aneurysmal sac from the blood circulation. The focus and this manuscript combining literature review and our original research is an analysis of changes in aneurysmal hemodynamics caused by endovascular treatment devices. Knowledge of post-treatment hemodynamics is a path to successful long-term treatment. Summarizing findings on hemodynamic impact of treatment devices, we conclude: coiling and stenting do not affect post-treatment intra-aneurysmal pressure, but significantly alter aneurysmal hemodynamics through flow reduction and a change in flow structure. The impact of treatment devices on aneurysmal flow depends, however, on a set of parameters including device geometry, course of placement, parent vessel and aneurysm geometry.

  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. Controlled release of osteopontin and interleukin-10 from modified endovascular coil promote cerebral aneurysm healing.

    PubMed

    Chen, Jingyi; Yang, Lijun; Chen, Yan; Zhang, Gengshen; Fan, Zheneng

    2016-01-15

    Cerebral aneurysm is a bulging of the artery inside the brain that results from a weakened or thin area of the artery wall. Ruptured cerebral aneurysm could lead to serious brain damage or even death, thus the proper treatment is essential. Compared with the conventional microsurgical clipping approach, the endovascular coiling treatment has many advantages, however, with a major disadvantage of high recurrence rate. One way to lower the recurrence rate, which has been tried since one decade ago, is to modify the coil to be bioactive and releasing biological molecules to stimulate tissue ingrowth and aneurysm healing. We have identified three candidates including osteopontin (OPN), IL-10 and matrix metallopeptidase 9 (MMP-9) from previous studies and generated platinum coils coated with these proteins in the carrier of poly-DL-lactic glycolic acid (PLGA). We were interested to know whether coils coated with OPN, IL-10 and MMP-9 were able to promote aneurysm healing and we have tested it in the rat carotid aneurysm model. We found that OPN and IL-10 coated coils had shown significant improvement in tissue ingrowth while MMP-9 coated coils failed to enhance tissue ingrowth compared with the control group. Our studies suggested the possible application of OPN and IL-10 coated coils in aneurysm treatment to overcome the recurrence.

  11. 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

  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. 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.

  14. 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

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

    PubMed

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

    2016-08-01

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

  16. 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.

  17. Gene Flow in Genetically Modified Wheat

    PubMed Central

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

    2011-01-01

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

  18. 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

  19. 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

  20. 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.

  1. 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.

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

    PubMed

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

    2015-12-01

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

  3. 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.

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

    PubMed

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

    2014-10-01

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

  5. Endovascular Treatment of Two High-Flow Brain Arteriovenous Fistulas with a Combination of Detachable Coils and Onyx in an Infant: Case Report and Review of Literature.

    PubMed

    Wang, Qihong; Quan, Zhe; Li, ZhiQiang

    2015-01-01

    Congenital brain arteriovenous fistulas (BAVFs) are rare neurovascular lesions of the brain, and few cases have been reported of their treatment with a combination of detachable coils and Onyx, especially in infants. Here, we present a case of 2 high-flow BAVFs occurring in a 12-month-old boy. Standard techniques of digital subtraction angiography were used, and dimethyl sulfoxide-compatible microcatheters were delivered and entered into a distal feeding artery as closely as possible to the fistulas. Then, a combination of detachable coils and Onyx was used. After the treatment of the 2 high-flow BAVFs, a complete percutaneous embolization of the fistulas was obtained. The fistulas remained closed, as ascertained by follow-up angiograms. No new neurological deficit related to the procedure was detected, and the infant was asymptomatic and in good health 4 years after the surgery. Our case shows that the endovascular treatment of high-flow BAVFs with a combination of detachable coils and Onyx in an infant is safe and effective.

  6. Endovascular Treatment of Two High-Flow Brain Arteriovenous Fistulas with a Combination of Detachable Coils and Onyx in an Infant: Case Report and Review of Literature.

    PubMed

    Wang, Qihong; Quan, Zhe; Li, ZhiQiang

    2015-01-01

    Congenital brain arteriovenous fistulas (BAVFs) are rare neurovascular lesions of the brain, and few cases have been reported of their treatment with a combination of detachable coils and Onyx, especially in infants. Here, we present a case of 2 high-flow BAVFs occurring in a 12-month-old boy. Standard techniques of digital subtraction angiography were used, and dimethyl sulfoxide-compatible microcatheters were delivered and entered into a distal feeding artery as closely as possible to the fistulas. Then, a combination of detachable coils and Onyx was used. After the treatment of the 2 high-flow BAVFs, a complete percutaneous embolization of the fistulas was obtained. The fistulas remained closed, as ascertained by follow-up angiograms. No new neurological deficit related to the procedure was detected, and the infant was asymptomatic and in good health 4 years after the surgery. Our case shows that the endovascular treatment of high-flow BAVFs with a combination of detachable coils and Onyx in an infant is safe and effective. PMID:26183946

  7. 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.

  8. 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.

  9. 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

  10. 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.

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

    PubMed Central

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

    2015-01-01

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

  12. Glubran 2: A New Acrylic Glue for Neuroradiological Endovascular Use

    PubMed Central

    Leonardi, M.; Barbara, C.; Simonetti, L.; Giardino, R.; Nicoli Aldini, N.; Fini, M.; Martini, L.; Masetti, L.; Joechler, M.; Roncaroli, F.

    2002-01-01

    Summary A new acrylic glue, Glubran 2, is now available on the European market. It bears the CE mark with several surgical indications and the specific indication for neuroradiological endovascular use. Despite this approval, to our knowledge its use is still limited to surgery and no injections have been made in human patients. This study was designed to evaluate the behavior of Glubran 2 in endovascular injection in a simulation of brain AVM. Six sheep were operated on opening a fistula between the right common carotid artery and the jugular vein. This fistula modifies blood flow in the skull base rete mirabilis, which then functions as an AVM. In two sheep, the rete mirabilis was occluded by injection of 1.5 ml of Histoacryl diluted 1:1 and 1:3 with Lipiodol. In two sheep, the rete was embolized by injection of 1.5 ml of Glubran 2 diluted 1:1 with Lipiodol. The last two sheep were embolized by injection of Glubran 2 diluted 1:3 with Lipiodol. The procedures were documented by DSA angiographic acquisitions and by fluoroscopic VHS. The sheep were killed immediately after the procedures and the rete mirabilis isolated for histologic examination. Embolization was obtained with both kinds of glue. Glubran 2 diffuses in a very similar way to Histoacryl with an apparently more complete diffusion. Reflux in the ascending pharyngeal artery showed that Glubran 2 tended not to produce bubbles but diffused more homogeneously. The subjective conclusion of this work is that Glubran 2 can be used in endovascular embolizations. Before approaching brain AVMs, a further study will investigate embolization of the external carotid territory. PMID:20594482

  13. 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

  14. 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

  15. 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.

  16. 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

  17. [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.

  18. [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

  19. 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

  20. 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.

  1. 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

  2. Endovascular aortic aneurysm operations.

    PubMed

    Najibi, Sasan; Terramani, Thomas T; Weiss, Victor J; Smith, Robert B; Salam, Atef A; Dodson, Thomas F; Chaikof, Elliot L; Lumsden, Alan B

    2002-02-01

    Options for the treatment of abdominal and thoracic aortic aneurysms are in a state of evolutionary change. The development and continued refinement of the endoluminal approaches has decreased the need for open aortic aneurysm surgery. Endovascular stent graft technology is an area of active research in which both the delivery systems and the endografts are undergoing continued improvement so that patients with what was previously thought to be unfavorable anatomy may be treated by these means. The design and deployment techniques of the currently available endografts, as well as those in clinical trials, are presented. PMID:11822962

  3. 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.

  4. 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

  5. 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.

  6. 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

  7. Endovascular treatment of infectious intracranial aneurysms.

    PubMed

    Gross, Bradley A; Puri, Ajit S

    2013-01-01

    Infectious intracranial aneurysms (IIA) are rare but a considerable source of morbidity and mortality as a result of rupture. Most patients with these lesions have considerable medical comorbidities, making endovascular approaches a crucial modality in their treatment armamentarium. Contributing our own case, we performed a comprehensive review of the literature to illustrate overall results and outcomes for patients with IIA treated with endovascular approaches. Incorporating our own case, we found 65 patients harboring 72 IIA across 31 reports. Fifty-one were treated via parent artery occlusion (71%), 17 via direct aneurysm embolization (24%), two via stent-coiling (3%), and two with stent monotherapy (3%). Twenty-nine IIAs were treated with n-butylcyanoacrylate (NBCA) (40%), 25 with coils (35%), seven with Onyx or ethylene vinyl alcohol (10%), five with detachable balloons (7%), four with stents (6%), and one with autologous clot (1%). One case of incomplete aneurysm occlusion and two cases of recanalization were reported. Six symptomatic periprocedural ischemic events were reported (9%), with only three resulting in permanent sequelae (5%). No infectious complications were reported. Incorporating the natural history of the disease, 28 patients were neurologically intact (43%), while seven had died at the time of follow-up (11%). Endovascular treatment of ruptured, symptomatic, or enlarging IIA is an excellent treatment modality with high occlusion rates and low procedure-related complication rates. Distal IIA are more often treated with parent artery occlusion, in our hands, preferentially with Onyx, while proximal lesions may be treated with direct stent-coiling or even flow-diverting stent monotherapy.

  8. A Patient with Eight Intracranial Aneurysms: Endovascular Treatment in Two Sessions

    PubMed Central

    Onan, Hasan Bilen; Balli, Huseyin Tugsan; Cetinalp, Nuri Eralp

    2016-01-01

    The frequency of multiple intracranial aneurysms seen in patients with or without subarachnoid hemorrhage is high. The advancement of the endovascular technique and devices has ensured that endovascular treatment of intracranial aneurysms is the first choice in most cases, especially in unruptured ones. Different combinations of treatment modalities and techniques can be used in the management of multiple aneurysms. But in selected patients without subarachnoid hemorrhage, treatment of all aneurysms in one or more sessions with endovascular techniques is less traumatic than that with surgery. In the literature, the maximum number of aneurysms in one patient treated endovascularly and/or surgically is seven. In this case report, we present, with a review of the literature, a patient with eight intracranial aneurysms, all of which were treated in two sessions with various endovascular techniques. A 40-year-old female patient was admitted due to headache. Angiography showed eight aneurysms in the posterior circulation and, bilaterally, in the anterior circulation. All aneurysms were treated endovascularly in two sessions. In the treatment of the aneurysms, different endovascular techniques were used including flow diverters stents, stent-assisted coiling, Y-stent-assisted coiling, and coiling alone. PMID:27668108

  9. A Patient with Eight Intracranial Aneurysms: Endovascular Treatment in Two Sessions

    PubMed Central

    Onan, Hasan Bilen; Balli, Huseyin Tugsan; Cetinalp, Nuri Eralp

    2016-01-01

    The frequency of multiple intracranial aneurysms seen in patients with or without subarachnoid hemorrhage is high. The advancement of the endovascular technique and devices has ensured that endovascular treatment of intracranial aneurysms is the first choice in most cases, especially in unruptured ones. Different combinations of treatment modalities and techniques can be used in the management of multiple aneurysms. But in selected patients without subarachnoid hemorrhage, treatment of all aneurysms in one or more sessions with endovascular techniques is less traumatic than that with surgery. In the literature, the maximum number of aneurysms in one patient treated endovascularly and/or surgically is seven. In this case report, we present, with a review of the literature, a patient with eight intracranial aneurysms, all of which were treated in two sessions with various endovascular techniques. A 40-year-old female patient was admitted due to headache. Angiography showed eight aneurysms in the posterior circulation and, bilaterally, in the anterior circulation. All aneurysms were treated endovascularly in two sessions. In the treatment of the aneurysms, different endovascular techniques were used including flow diverters stents, stent-assisted coiling, Y-stent-assisted coiling, and coiling alone.

  10. 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.

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

    NASA Astrophysics Data System (ADS)

    Saleem, H.; Ali, S.; Haque, Q.

    2015-08-01

    The nonlinear dynamics of ion-acoustic waves is investigated in a plasma having field-aligned shear flow. A Koeteweg-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.

  12. Intraoperative endovascular ultrasonography

    NASA Astrophysics Data System (ADS)

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

    1991-05-01

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

  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. Performance of a nitrogen laser with a modified electrode configuration and gas flow arrangement

    NASA Astrophysics Data System (ADS)

    Itagi, V. V.; Pawar, B. H.; Itagi, S.

    1980-10-01

    A Blumlein discharge N2 laser with modified electrode structure and gas flow arrangement is described. The compact nitrogen laser has a brass anode and hacksaw blade cathode, with the nitrogen flow across the electrodes and the Blumlein line formed by copper and aluminum sheets, with polyester as the dielectric. Output power is measured as a function of pressure, voltage and flow rate, and the trend of the power output towards saturation could be due to a nonlinear dependence of the excitation cross section on the electron temperature, which depends on the charging voltage. The laser can pump some dyes to amplified spontaneous emission and can trigger spark gaps.

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

    PubMed Central

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

    2016-01-01

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

  16. Techniques in Endovascular Aneurysm Repair

    PubMed Central

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

    2011-01-01

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

  17. 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

  18. Applicability of the modified XPP model to a description of flow behaviour of polymeric materials

    NASA Astrophysics Data System (ADS)

    Pivokonsky, Radek; Filip, Petr; Zelenkova, Jana

    2015-04-01

    A 3N-parameter (3 parameters per mode) phenomenological modification of the XPP model for a description of the rheological properties of polymer melts is proposed. The predictive/fitting capabilities of the modified XPP model are compared with the Giesekus, XPP, and modified Leonov models using various polymeric materials in steady shear and uniaxial elongational flows. Its predictability of the rheological properties of the studied materials seems to be very good, including strain hardening in uniaxial elongational flow. Consequently, the GS derivative term was implemented into this modified XPP model. Then the model contains two linear parameters per mode (relaxation time and shear modulus) and two non-linear ones (the fitting parameter simultaneously controlling both strain hardening in elongation flow and shear thinning, and the slip parameter influencing almost solely shear thinning). The efficiency of this model is tested using LDPE and HDPE materials and compared with the modified Leonov model and network-based exponential PTT and PTT-XPP models, both of them containing the GS derivative term.

  19. Bioresorbable Electronic Stent Integrated with Therapeutic Nanoparticles for Endovascular Diseases.

    PubMed

    Son, Donghee; Lee, Jongha; Lee, Dong Jun; Ghaffari, Roozbeh; Yun, Sumin; Kim, Seok Joo; Lee, Ji Eun; Cho, Hye Rim; Yoon, Soonho; Yang, Shixuan; Lee, Seunghyun; Qiao, Shutao; Ling, Daishun; Shin, Sanghun; Song, Jun-Kyul; Kim, Jaemin; Kim, Taeho; Lee, Hakyong; Kim, Jonghoon; Soh, Min; Lee, Nohyun; Hwang, Cheol Seong; Nam, Sangwook; Lu, Nanshu; Hyeon, Taeghwan; Choi, Seung Hong; Kim, Dae-Hyeong

    2015-06-23

    Implantable endovascular devices such as bare metal, drug eluting, and bioresorbable stents have transformed interventional care by providing continuous structural and mechanical support to many peripheral, neural, and coronary arteries affected by blockage. Although effective in achieving immediate restoration of blood flow, the long-term re-endothelialization and inflammation induced by mechanical stents are difficult to diagnose or treat. Here we present nanomaterial designs and integration strategies for the bioresorbable electronic stent with drug-infused functionalized nanoparticles to enable flow sensing, temperature monitoring, data storage, wireless power/data transmission, inflammation suppression, localized drug delivery, and hyperthermia therapy. In vivo and ex vivo animal experiments as well as in vitro cell studies demonstrate the previously unrecognized potential for bioresorbable electronic implants coupled with bioinert therapeutic nanoparticles in the endovascular system.

  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. The Past, Present and Future of Endovascular Aneurysm Treatment.

    PubMed

    Henkes, H; Weber, W

    2015-10-01

    The technology available for the endovascular treatment of intracranial aneurysms is rapidly evolving. Both current and future devices are described. This includes, among others, UNO for parent vessel occlusion, the Medina device for saccular filling, the Comaneci device for remodeling, pCONus for assisted coil occlusion, and WEB and pCANvas for intrasaccular flow disruption. Perspectives of further development such as surface coating for increased radioopacity and decreased thrombogenicity are explained.

  2. 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

  3. 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.

  4. Whiteness process of tile ceramics: using a synthetic flow as a modifier agent of color firing

    NASA Astrophysics Data System (ADS)

    dos Santos, G. R.; Pereira, M. C.; Olzon-Dionysio, M.; de Souza, S. D.; Morelli, M. R.

    2014-01-01

    Synthetic flow is proposed as a modifier agent of color firing in tile ceramic mass during the sinterization process, turning the red color firing into whiteness. Therefore, the 57Fe Mössbauer spectroscopy was used to understand how the interaction of the iron element in the mechanism of color firing mass occurs in this system. The results suggest that the change of color firing can be alternatively due to two main factors: (i) diluting the hematite content in the sample because of the use of synthetic flow and (ii) part of the hematite is converted in other uncolored crystal structures, which makes the final color firing lighter.

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

    PubMed Central

    Leotta, Daniel F.; Starnes, Benjamin W.

    2015-01-01

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

  6. 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

  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.

  8. 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

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

    PubMed Central

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

    2015-01-01

    ABSTRACT Endovascular coil embolization of arterial aneurysms is often complicated by reduced blood flow to branching arteries. To determine the optimal coil configuration for safe embolization of endovascular aneurysms without compromising blood flow in branching arteries. A 3-dimensional voxel model, built based on an unruptured vertebral artery–posterior inferior cerebellar artery (VA–PICA) aneurysm, predicted to show impairment of flow in the PICA during endovascular coil embolization (Case 0). Six different models of final coil configuration were generated and applied to this aneurysm. Case 1 was a round coil mass. Case 2 was designed with a stent assist. Cases 3, and 4 were designed with a neck remnant and Cases 5 and 6 incorporated a balloon neck remodeling technique. Computational fluid dynamics was used to analyze the flow in the PICA in each model. The average outflow to the PICA was highest in Case 0 and lowest in Case 2 (in descending order, Case 0, 5, 4, 6, 1, 3, and 2). There was better preservation of outflow to the PICA in the balloon neck remodeling models than in the neck remnant models. In a model of endovascular coil embolization, we found considerable differences in outflow to the branching artery with small changes in coil configuration. Careful preoperative planning is important to minimize the risk of thromboembolic events during and after endovascular coil embolization. PMID:26412884

  10. Assessing skin blood flow dynamics in older adults using a modified sample entropy approach.

    PubMed

    Liao, Fuyuan; Jan, Yih-Kuen

    2014-01-01

    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.

  11. 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.

  12. 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.

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

    PubMed

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

    2014-04-01

    Balloon-assisted embolization performed by delivering Onyx ethylene vinyl alcohol copolymer through a dual-lumen coaxial balloon microcatheter is a new technique for the management of peripheral vascular lesions. This technique does not require an initial reflux of Onyx to form around the tip of the microcatheter before antegrade flow of Onyx can commence. In a series of four patients who were treated with the use of this technique, the absence of significant reflux of Onyx was noted, as were excellent navigability and easy retrieval of the balloon microcatheter. However, in one patient, there was inadvertent adverse embolization of a digital artery, which was not caused by reflux of Onyx but could still be related to balloon inflation. PMID:24674217

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

    PubMed

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

    2014-04-01

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

  15. 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

  16. A modified PANS model for computations of unsteady turbulence cavitating flows

    NASA Astrophysics Data System (ADS)

    Hu, ChangLi; Wang, GuoYu; Chen, GuangHao; Huang, Biao

    2014-10-01

    A modification to the PANS (partially averaged Navier-Stokes) model is proposed to simulate unsteady cavitating flows. In the model, the parameter f k is modified to vary as a function of the ratios between the water density and the mixture density in the local flows. The objective of this study is to validate the modified model and further understand the interaction between turbulence and cavitation around a Clark-Y hydrofoil. The comparisons between the numerical and experiment results show that the modified model can be improved to predict the cavity evolution, vortex shedding frequency and the lift force fluctuating in time fairly well, as it can effectively modulate the eddy viscosity in the cavitating region and various levels of physical turbulent fluctuations are resolved. In addition, from the computational results, it is proved that cavitation phenomenon physically influences the turbulent level, especially by the vortex shedding behaviors. Also, the mean u-velocity profiles demonstrate that the attached cavity thickness can alter the local turbulent shear layer.

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

    PubMed

    Li, Yuyuan; Xing, Da; Zhang, Chunsun

    2009-02-01

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

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

    PubMed

    Resnick, Andrew

    2011-01-01

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

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

    PubMed

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

    2016-02-15

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

  20. Endovascular repair of a Kommerell diverticulum anomaly.

    PubMed

    Gao, Peixian; Wang, Mo; Dong, Dianning; Kong, Xiangqian; Jin, Xing; Zhang, Shiyi

    2015-05-01

    A Kommerell diverticulum (KD) may predispose toward aortic aneurysm, dissection, or rupture, although they are primarily asymptomatic. We report a case of an aberrant left subclavian artery arising from a KD in a right-side aortic arch. The lesions were successfully treated by an endovascular approach involving Amplatzer vascular plug embolization of the aberrant left subclavian artery and endovascular repair of the KD.

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

    SciTech Connect

    Massoudi, Mehrdad; Tran, P.X.

    2008-07-01

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

  2. 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

  3. 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.

  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. Modifying intake flow to increase EGR tolerance in an Internal Combustion Engine

    NASA Astrophysics Data System (ADS)

    Rubio, Daniel; Drabo, Mebougna; Puzinauskas, Paul

    2010-11-01

    The worldwide effort to reduce vehicle emissions and increase fuel efficiencies has continuously intensified as the need to improve air quality and reduce fuel consumption becomes more acute. Exhaust gas recirculation (EGR) is a method that has long been employed to reduce combustion temperatures and therefore reduce thermal NOx formation and accommodate higher compression ratios and more optimum combustion phasing for improved efficiency. Generally the effective EGR level as a percent of trapped charge is limited by its affect on combustion stability. Inducing flow structures such as swirl, squish and tumble in the trapped charge have proven to extend this EGR limit in homogeneous charge spark-ignited engines at part load, but this enhancement has not been significantly studied at full loads in such engines. This research explored modifying the intake flow into an engine to create tumble and evaluate its effect at high loads in such engines. This exploration included characterizing the flow on a steady flow bench and quantifying the results using engine dynamometer tests.

  6. 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

  7. 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.

  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. Endovascular abdominal aortic aneurysm repair

    PubMed Central

    Norwood, M G A; Lloyd, G M; Bown, M J; Fishwick, G; London, N J; Sayers, R D

    2007-01-01

    The operative mortality following conventional abdominal aortic aneurysm (AAA) repair has not fallen significantly over the past two decades. Since its inception in 1991, endovascular aneurysm repair (EVAR) has provided an alternative to open AAA repair and perhaps an opportunity to improve operative mortality. Two recent large randomised trials have demonstrated the short and medium term benefit of EVAR over open AAA repair, although data on the long term efficacy of the technique are still lacking. This review aimed at providing an overview of EVAR and a discussion of the potential benefits and current limitations of the technique. PMID:17267674

  10. 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.

  11. 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.

  12. 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.

  13. 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

  14. Development of an ovine model of occlusive arterial injury for the evaluation of endovascular interventions.

    PubMed

    Reva, Viktor A; Morrison, Jonathan J; Denisov, Alexey V; Seleznev, Alexey B; Zhabin, Anatoly V; Bozhedomova, Elvira R; Samokhvalov, Igor M

    2016-10-01

    Endovascular intervention for occlusive arterial trauma is becoming more common in clinical practice. The aim of this study is to present an ovine model of extremity arterial injury for use in future endovascular translational research. Animals under general anesthesia had their left superficial femoral artery exposed, which was bluntly injured over a 2-cm section using a hemostat and injection of air. Occlusion was confirmed on angiography and the flow characteristics measured by ultrasonography. Of five animals enrolled, four occluding lesions were created successfully. Post injury, there was a significant reduction in the median (interquartile range) systolic velocity (cm/sec) on the left (injury) compared to the right (control) side (3.5 (0-16.5) vs. 29 (23.8-43.3); p < 0.001). The ovine superficial femoral artery can be used to consistently produce an occlusive lesion that is suitable for use in the future evaluation of endovascular trauma interventions. PMID:26546598

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

    PubMed

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

    2014-03-01

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

  16. Discrete element simulation of dense granular flow in a modified Couette cell.

    SciTech Connect

    Lechman, Jeremy B.; Grest, Gary Stephen

    2005-02-01

    Large-scale three dimensional Discrete Element simulations of granular flow in a modified split-bottom Couette cell for packs of up to 180,000 mono-disperse spheres are presented and compared with experiments. We find that the velocity profiles collapse onto a universal curve not only at the surface but also in the bulk of the pack until slip between layers becomes significant. In agreement with experiment, we find similar relations between the cell geometry and parameters involved in rescaling the velocities at the surface and in the bulk. Likewise, a change in the shape of the shear zone is observed as predicted for tall packs once the center of the shear zone is correctly defined; although the transition does not appear to be first order. Finally, the effect of cohesion is considered as a means to test the theoretical predictions.

  17. 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.

  18. Emergency endovascular treatment of popliteal aneurysms.

    PubMed

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

    2010-12-01

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

  19. 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

  20. Endovascular repair of abdominal aortic aneurysms.

    PubMed

    Arnaoutakis, Dean J; Zammert, Martin; Karthikesalingam, Alan; Belkin, Michael

    2016-09-01

    Endovascular repair of abdominal aortic aneurysms is an important technique in the vascular surgeon's armamentarium, which has created a seismic shift in the management of aortic pathology over the past two decades. In comparison to traditional open repair, the endovascular approach is associated with significantly improved perioperative morbidity and mortality. The early survival benefit of endovascular abdominal aortic aneurysm repair is sustained up to 3 years postoperatively, but longer-term life expectancy remains poor regardless of operative modality. Nonetheless, most abdominal aortic aneurysms are now repaired using endovascular stent grafts. The technology is not perfect as several postoperative complications, namely endoleak, stent-graft migration, and graft limb thrombosis, can develop and therefore lifelong imaging surveillance is required. In addition, a postoperative inflammatory response has been documented after endovascular repair of aortic aneurysms; the clinical significance of this finding has yet to be determined. Subsequently, the safety and applicability of endovascular stent grafts are likely to improve and expand with the introduction of newer-generation devices and with the simplification of fenestrated systems. PMID:27650343

  1. 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

  2. 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

  3. 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

  4. Young Adult Patent Ductus Arteriosus Treated with Endovascular Stent Grafting

    PubMed Central

    Liu, Pin-Hung; Kang, Pei-Leun; Lin, Yu-Hsin

    2016-01-01

    Endovascular stent-grafting is an alternative treatment for adult patent ductus arteriosus (PDA), especially in elderly patients. Regarding young adults, endovascular therapy is a reasonable choice if the landing zone is sufficient. In this study, we report on a young adult with PDA successfully treated with endovascular stent-grafting.

  5. 21 CFR 870.3460 - Endovascular Suturing System.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Endovascular Suturing System. 870.3460 Section 870...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3460 Endovascular Suturing System. (a) Identification. An endovascular suturing system is a medical device intended to...

  6. 21 CFR 870.3460 - Endovascular Suturing System.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Endovascular Suturing System. 870.3460 Section 870...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3460 Endovascular Suturing System. (a) Identification. An endovascular suturing system is a medical device intended to...

  7. Cardiorespiratory fitness modifies the relationship between myocardial function and cerebral blood flow in older adults.

    PubMed

    Johnson, Nathan F; Gold, Brian T; Bailey, Alison L; Clasey, Jody L; Hakun, Jonathan G; White, Matthew; Long, Doug E; Powell, David K

    2016-05-01

    A growing body of evidence indicates that cardiorespiratory fitness attenuates some age-related cerebral declines. However, little is known about the role that myocardial function plays in this relationship. Brain regions with high resting metabolic rates, such as the default mode network (DMN), may be especially vulnerable to age-related declines in myocardial functions affecting cerebral blood flow (CBF). This study explored the relationship between a measure of myocardial mechanics, global longitudinal strain (GLS), and CBF to the DMN. In addition, we explored how cardiorespiratory affects this relationship. Participants were 30 older adults between the ages of 59 and 69 (mean age=63.73years, SD=2.8). Results indicated that superior cardiorespiratory fitness and myocardial mechanics were positively associated with DMN CBF. Moreover, results of a mediation analysis revealed that the relationship between GLS and DMN CBF was accounted for by individual differences in fitness. Findings suggest that benefits of healthy heart function to brain function are modified by fitness.

  8. 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

  9. 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.

  10. Cardiorespiratory fitness modifies the relationship between myocardial function and cerebral blood flow in older adults.

    PubMed

    Johnson, Nathan F; Gold, Brian T; Bailey, Alison L; Clasey, Jody L; Hakun, Jonathan G; White, Matthew; Long, Doug E; Powell, David K

    2016-05-01

    A growing body of evidence indicates that cardiorespiratory fitness attenuates some age-related cerebral declines. However, little is known about the role that myocardial function plays in this relationship. Brain regions with high resting metabolic rates, such as the default mode network (DMN), may be especially vulnerable to age-related declines in myocardial functions affecting cerebral blood flow (CBF). This study explored the relationship between a measure of myocardial mechanics, global longitudinal strain (GLS), and CBF to the DMN. In addition, we explored how cardiorespiratory affects this relationship. Participants were 30 older adults between the ages of 59 and 69 (mean age=63.73years, SD=2.8). Results indicated that superior cardiorespiratory fitness and myocardial mechanics were positively associated with DMN CBF. Moreover, results of a mediation analysis revealed that the relationship between GLS and DMN CBF was accounted for by individual differences in fitness. Findings suggest that benefits of healthy heart function to brain function are modified by fitness. PMID:26032886

  11. 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

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

    NASA Astrophysics Data System (ADS)

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

    2005-02-01

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

  13. Pneumatic compression for embolic protection during upper extremity endovascular intervention.

    PubMed

    Cassar, Andrew; Barsness, Gregory W; Wysokinski, Waldemar E; Gifford, Shaun M; Bower, Thomas C; Edwards, William D; Gulati, Rajiv

    2014-01-01

    Embolic protection devices are occasionally employed during endovascular interventions to prevent complications caused by embolic debris. However, these devices have imperfect efficacy, confer risk of endovascular trauma, and are expensive. We report a patient with giant cell arteritis and symptomatic axillary artery stenosis, with a perceived elevated risk of distal embolization during endovascular intervention. We describe a straightforward embolic protection technique of brachial pressure cuff inflation during endovascular intervention and aspiration of displaced thrombotic material from the static column of blood. This novel, effective, and cost-free technique could also be employed in other vascular beds during endovascular intervention.

  14. Endovascular treatment of arteriovenous malformations.

    PubMed

    Diaz, Orlando; Scranton, Robert

    2016-01-01

    Cerebral arteriovenous malformations (AVM) are tangles of blood vessels that permit shunting of blood from the arterial to venous phase without intervening capillaries. The malformation's arterialization of a low-pressure system creates a risk of rupture that is substantially higher when associated with an aneurysm. The annual hemorrhage rate is 2.2% per year as reported in the randomized trial of unruptured brain AVMs (ARUBA; rupture risk is increased after the first event. Ruptured AVMs have a 10% mortality rate and 20%-30% morbidity rate. The treatment of choice for AVMs is microvascular resection with or without preoperative embolization. Surgical risk can be stratified based on the Spetzler-Martin grading system. Liquid embolic material and coils may be used for the treatment of AVM associated aneurysms, especially in the setting of acute rupture as a bridge to delayed surgical resection. There is some limited reported success in total endovascular treatment of AVMs, but this is not considered standard therapy at this time. Stereotactic radiosurgery (SRS) has been recently described but mainly limited to AMVs deemed too risky to approach in an open fashion and limited to 2.5cm-3cm in size. The delayed protection from hemorrhage (approximately 2-3 years) and high marginal failure/recurrence rate are the greatest concerns. PMID:27430471

  15. Rapid endovascular warming for profound hypothermia.

    PubMed

    Laniewicz, Megan; Lyn-Kew, Kenneth; Silbergleit, Robert

    2008-02-01

    Profound hypothermia is associated with high mortality and morbidity. Optimal outcomes have been reported with invasive extracorporeal warming techniques not readily available in most hospitals. Endovascular warming devices may provide a less invasive alternative. A 68-year-old woman developed profound hypothermia after environmental exposure. On arrival, she was comatose, severely bradycardic, without palpable pulses, and with a core body temperature of 23.0 degrees C (72 degrees F). Attempts to warm her with traditional methods during 2 hours were ineffective. An endovascular temperature control system was placed and effectively warmed the patient at about 3 degrees C (4.5 degrees F) per hour, with return of hemodynamic stability. When hypothermia is profound, surface warming works poorly and invasive strategies, including cardiopulmonary bypass, are recommended. Rapid warming from profound hypothermia can be accomplished with endovascular systems, and these may be an effective alternative to more invasive extracorporeal methods. PMID:17681640

  16. 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.

  17. Endovascular Management of May-Thurner Syndrome

    PubMed Central

    Al Safran, Zakareya; Hasan, Hosam; Zeid, Wael Abu

    2012-01-01

    May-Thurner syndrome or iliac vein compression syndrome is associated with deep vein thrombosis (DVT) resulting from chronic compression of the left iliac vein against lumbar vertebrae by the overlying right common iliac artery. Historically, May-Thurner syndrome has been treated with anticoagulation therapy. However, this therapy can be problematic when given alone, because it prevents the propagation of the thrombus without eliminating the existing clot. Furthermore, it does not treat the underlying mechanical compression. Consequently, syndrome who was managed by anticoagulation therapy alone, there is a significant chance that the patient will develop recurrent deep vein thrombosis or post thrombotic syndrome or both. Recently, both retrospective and prospective studies have suggested that endovascular management should be front-line treatment; endovascular management actively treats both the mechanical compression with stent placement and the thrombus burden with chemical dissolution. We report our case of 53 years old male patient with May Thurner syndrome who managed by endovascular treatment. PMID:23555515

  18. 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.

  19. 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

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

  1. 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

  2. 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

  3. 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.

  4. 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

  5. Surgical and endovascular interventions for nutcracker syndrome.

    PubMed

    Avgerinos, Efthymios D; McEnaney, Ryan; Chaer, Rabih A

    2013-12-01

    Nutcracker syndrome is a rare condition of left renal vein entrapment manifesting with hematuria, flank pain, and, occasionally, pelvic congestion in females or varicocele in males. Diagnosis requires a high index of suspicion upon careful history delineation. The gold standard for definite confirmation remains venography with renocaval pressure gradient. Treatment is mainly guided by the severity of symptoms. For the majority of centers, it appears that surgery remains the first-line therapy, however, endovascular alternatives are rapidly evolving into the field with favorable outcomes. This article reviews current concepts on nutcracker syndrome with particular focus on contemporary surgical and endovascular techniques and their outcomes.

  6. [Molecular and immunological approach to hematological disease: detection and analysis of intracellular modified nucleosides by flow cytometry].

    PubMed

    Hoshino, A; Honda, I; Ishimori, A; Itoh, K; Mizugaki, M; Nose, M

    1990-07-01

    Modified nucleosides are components of ribosomal RNA (rRNA), transfer RNA (tRNA) and messenger RNA (mRNA). 1-methyladenosine and pseudouridine are members of those modified nucleosides. The urinary concentration of 1-methyladenosine and pseudouridine of cancer patients are higher than that of healthy controls, and those compounds were reduced after effective chemotherapy. Thus those compounds might be expected to use as tumor markers. In this study cellular origin of 1-methyladenosine and pseudouridine were analysed about two tumor cell lines (HUT-102, THP-1), peripheral blood lymphocytes (PBL) from healthy adult and PBL under the phytohemagglutinin stimulation, by flow cytometric analysis and immunofluorescent staining of cellular RNA using monoclonal antibodies specific for 1-methyladenosine (AMA) and pseudouridine (APU). Both 1-methyladenosine and pseudouridine were detected in more than 90% of tumor cells above the thresholds of flow cytometric detection (Spectrum III, Ortho). The PBL under the PHA stimulation also tended to take the same way of the tumor cell lines, whereas few of the PBL contained 1-methyladenosine above the thresholds. According to the DNA analysis of those cell lines, high contents of the modified nucleosides in the cell might follow DNA synthesis, this leads to one reason for high levels of the urinary excretion of the modified nucleosides in cancer patient.

  7. Stent Graft-in-Stent Graft as a Rescue Technique for Endovascular Treatment of Giant Extracranial Internal Carotid Aneurysm

    PubMed Central

    Jeha, Salim Abdon Haber

    2016-01-01

    Endovascular treatment of a giant extracranial internal carotid aneurysm by a stent graft implantation was unsuccessful due to a high flow leak directly through the stent graft's coating. The problem was solved deploying a second stent graft inside the previously implanted one resulting in complete exclusion of the aneurysmal sac and patent carotid lumen preservation. The review of the literature did not provide a case using this endovascular strategy. Follow-up for more than 12 months, using CT angiography, showed confirmed aneurysmal exclusion and carotid patency and no clinical complications have been detected. PMID:27752387

  8. 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.

  9. 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.

  10. 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.

  11. Endovascular stent placement for nutcracker phenomenon.

    PubMed

    Li, Heping; Sun, Xiangzhou; Liu, Guihua; Zhang, Yuanyuan; Chu, Jianping; Deng, Chunhua; Zhou, Bo; Chen, Wei; Yang, Jianyong

    2013-01-01

    The nutcracker syndrome is a rare clinic condition associated with severe hematuria and left flank pain due to the entrapment of the left renal vein between the superior mesenteric artery and the aorta. Its diagnostic criteria are not well defined, often causing delayed or misdiagnosis. Although surgical repair has been the standard of care, more recently endovascular stenting of the renal vein has been proposed. We presented six patients (aged 7 to 31 years old; median age, 16.5 years old) with nutcracker syndrome who were endovascularly managed from June 2002 to July 2011. All patients underwent laboratory test and computed tomography (CT) or ultrasound examination before and after endovascular procedures. Self-expandable stents were successfully placed in all cases. The diameter of the left renal vein at aorto-superior mesenteric artery portion significantly increased from 1.88 ± 0.95 mm pre-procedure to 5.24 ± 0.61 mm post-procedure (p< 0.01). Left renal vein pressure significantly decreased from 11.00 ± 4.34 mmHg pre-procedure to 6.00 ± 2.55 mmHg post-procedure (p< 0.01). Severe gross hematuria completely subsided within 2 months to 6 months and left flank pain completely subsided within 7 days to 1 month after treatment. Endovascular therapy provides an alternative therapy with satisfactory long-term clinical and imaging results for symptomatic patients with nutcracker syndrome.

  12. 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

  13. Resection of a recurrent cervical internal carotid artery pseudoaneurysm after failed endovascular therapy

    PubMed Central

    Nguyen, Ha Son; Oni-Orisan, Akinwunmi; Cochran, Joseph; Pollock, Glen

    2016-01-01

    Background: Recurrence of a cervical internal carotid artery (ICA) pseudoaneurysm initially treated by endovascular means is rare. We report an instance where a patient returned with a recurrent, enlarging cervical ICA pseudoaneursym, 15 years after initial complete, endovascular occlusion of the ICA. Case Description: Patient is a 64-year-old male with a history of a right cervical ICA pseudoaneurysm diagnosed 15 years ago after a car accident. At the time, he received endovascular occlusion of his right ICA. Recent serial imaging demonstrated progressive enlargement of his pseudoaneurysm, up to 6 cm × 5 cm × 5.5 cm, without evidence of internal flow or extravasation. Due to dysphagia and hoarseness, resection of the pseudoaneurysm was recommended. Dissection occurred down to the lesion, where its borders were skeletonized. Its stump at the proximal ICA was mobilized and clamped; the lesion was incised and the existing thrombus, as well as the coil mass, was removed. The distal ICA appeared completely scarred with no retrograde filling. There were branches from the external carotid artery that appeared to supply the pseudoaneurysm. The scarred remnant of the distal ICA was sutured and the stump at the proximal ICA was ligated. Once hemostasis was obtained, closure occurred via anatomical layers. Postoperatively, the patient woke up well; at discharge, he exhibited no respiratory distress or dysphagia. At 5 months follow-up, a computed tomography angiography of the neck revealed no evidence for a residual pseudoaneurysm. He continues on lifelong aspirin. Conclusion: Recurrence of a cervical ICA pseudoaneursym is rare. We caution that such a clinical scenario is possible, even 15 years after endovascular occlusion of the ICA. Branches from the external carotid artery may feed the pseudoaneursym and cause recurrence. This mechanism has not been reported. Perhaps longer clinical follow-up is necessary, especially if endovascular therapy is the initial treatment

  14. 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.

  15. Calculation of plane turbulent Couette-Poiseuille flows with a modified k-ɛ model

    NASA Astrophysics Data System (ADS)

    Gretler, W.; Meile, W.

    1997-10-01

    Suitable modifications to the k—ɛ model are proposed for the calculation of turbulent Couette-Poiseuille flows. In the case of pure Couette flow a logarithmic expression for the turbulent kinetic energy could be derived which is valid over the entire fully turbulent region. The basic idea for numerical computations is the deviation from the concept of constant cμ. In the case of Couette-type flows proper distributions of this model parameter could be found. In Poiseuille-type flows the application of an extended eddy-diffusivity approach for the turbulent shear stress leads to results which satisfactorily correspond to the measurements.

  16. 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

  17. 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

  18. 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.

  19. 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.

  20. Functional flows in QED and the modified Ward-Takahashi identity

    NASA Astrophysics Data System (ADS)

    Igarashi, Yuji; Itoh, Katsumi; Pawlowski, Jan M.

    2016-10-01

    In the functional renormalisation group approach to gauge theory, the Ward-Takahashi identity is modified due to the presence of an infrared cutoff term. It take the most accessible form for the Wilsonian effective action. In the present work we solve these identities, partially, for the Wilsonian effective action of QED. In particular, we compute the longitudinal part of the photon two point vertex function as a momentum-dependent function in the presence of the cutoff k. The resultant Wilsonian effective action carries form factors that originate from the modified Ward-Takahashi identity. We show how this result carries over to the one-particle-irreducible effective action.

  1. 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.

  2. 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.

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

    EPA Science Inventory

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

  4. 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.

  5. 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

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

    PubMed

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

    2013-09-01

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

  7. Thoracic aorta dissection associated with aberrant right subclavian artery: treatment with endovascular stent-graft placement.

    PubMed Central

    Baccin, Carlos E.; Montenegro, Maria A.; Mourão, Guilherme S.

    2004-01-01

    Dissecting aneurysm is the condition produced by separation of the layers of the arterial wall by circulating blood. Although rare, the coexistence of aortic dissection and aberrant right subclavian artery may be catastrophic. In this study we report the endovascular treatment of a patient with thoracic aorta dissection associated with aberrant right subclavian artery. Aortic clamping proximal to the left subclavian artery in a patient with an aberrant right subclavian artery slows or eliminates flow to both vertebral arteries. Endovascular repair eliminates the complications associated with aortic clamping during surgical repair in the presence of an aberrant right subclavian artery; therefore, it should be considered the treatment of choice in this situation. PMID:15829146

  8. 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

  9. Surveillance Imaging Following Endovascular Aneurysm Repair

    PubMed Central

    Pandey, Nirnimesh; Litt, Harold I.

    2015-01-01

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

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. Explaining electrostatic charging and flow of surface-modified acetaminophen powders as a function of relative humidity through surface energetics.

    PubMed

    Jallo, Laila J; Dave, Rajesh N

    2015-07-01

    Powder flow involves particle-particle and particle-vessel contacts and separation resulting in electrostatic charging. This important phenomenon was studied for uncoated and dry-coated micronized acetaminophen (MAPAP) as a function of relative humidity. The main hypothesis is that by modifying powder surface energy via dry coating of MAPAP performed using magnetically assisted impaction coating, its charging tendency, flow can be controlled. The examination of the relationship between electrostatic charging, powder flow, and the surface energies of the powders revealed that an improvement in flow because of dry coating corresponded to a decrease in the charging of the particles. A general trend of reduction in both electrostatic charging and dispersive surface energy with dry coating and relative humidity were also observed, except that a divergent behavior was observed at higher relative humidities (≥55% RH). The uncoated powder was found to have strong electron acceptor characteristic as compared with the dry coated. The adhesion energy between the particles and the tubes used for the electrostatic charging qualitatively predicted the decreasing trend in electrostatic charging from plastic tubes to stainless steel. In summary, the surface energies of the powders and the vessel could explain the electrostatic charging behavior and charge reduction because of dry coating. PMID:25974039

  16. Explaining electrostatic charging and flow of surface-modified acetaminophen powders as a function of relative humidity through surface energetics.

    PubMed

    Jallo, Laila J; Dave, Rajesh N

    2015-07-01

    Powder flow involves particle-particle and particle-vessel contacts and separation resulting in electrostatic charging. This important phenomenon was studied for uncoated and dry-coated micronized acetaminophen (MAPAP) as a function of relative humidity. The main hypothesis is that by modifying powder surface energy via dry coating of MAPAP performed using magnetically assisted impaction coating, its charging tendency, flow can be controlled. The examination of the relationship between electrostatic charging, powder flow, and the surface energies of the powders revealed that an improvement in flow because of dry coating corresponded to a decrease in the charging of the particles. A general trend of reduction in both electrostatic charging and dispersive surface energy with dry coating and relative humidity were also observed, except that a divergent behavior was observed at higher relative humidities (≥55% RH). The uncoated powder was found to have strong electron acceptor characteristic as compared with the dry coated. The adhesion energy between the particles and the tubes used for the electrostatic charging qualitatively predicted the decreasing trend in electrostatic charging from plastic tubes to stainless steel. In summary, the surface energies of the powders and the vessel could explain the electrostatic charging behavior and charge reduction because of dry coating.

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

    SciTech Connect

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

    2010-08-15

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

  18. 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.

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

    PubMed

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

    2011-12-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2000-11-01

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

  1. Endovascular Treatment of ACom Intracranial Aneurysms

    PubMed Central

    Finitsis, S.; Anxionnat, R.; Lebedinsky, A.; Albuquerque, P.C.; Clayton, M.F.; Picard, L.; Bracard, S.

    2010-01-01

    Summary The immediate and long-term outcomes, complications, recurrences and the need for retreatment were analyzed in a series of 280 consecutive patients with anterior communicating artery aneurysms treated with the endovascular technique. From October 1992 to October 2001 280 patients with 282 anterior communicating artery aneurysms were addressed to our center. For the analysis, the population was divided into two major groups: group 1, comprising 239 (85%) patients with ruptured aneurysms and group 2 comprising of 42 (15%) patients with unruptured aneurysms. In group 1, 185 (77.4%) patients had a good initial pre-treatment Hunt and Hess grade of I-III. Aneurysm size was divided into three categories according to the larger diameter: less than 4 mm, between 4 and 10 mm and larger than 10 mm. The sizes of aneurysms in groups 1 and 2 were identical but a less favorable neck to depth ratio of 0.5 was more frequent in group 2. Endovascular treatment was finally performed in 234 patients in group 1 and 34 patients in group 2. Complete obliteration was more frequently obtained in group 2 unlike a residual neck or opacification of the sac that were more frequently seen in group 1. No peri-treatment complications were recorded in group 2. In group 1 the peri-treatment mortality and overall peri-treatment morbidity were 5.1% and 8.1% respectively. Eight patients (3.4%) in group 1 presented early post treatment rebleeding with a mortality of 88%. The mean time to follow-up was 3.09 years. In group 1, 51 (21.7%) recurrences occurred of which 14 were minor and 37 major. In group 2, eight (23.5%) recurrences occurred, five minor and three major. Two patients (0.8%) presented late rebleeding in group 1. Twenty-seven second endovascular retreatments were performed, 24 (10.2%) in group 1 and three (8.8%) in group 2, seven third endovascular retreatments and two surgical clippings in group 1 only. There was no additional morbidity related to retreatments. Endovascular treatment

  2. 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.

  3. Endovascular treatment of ruptured intracranial aneurysms in patients 70 years of age and older

    PubMed Central

    Watanabe, Daisuke; Hashimoto, Takao; Koyama, Shunichi; Ohashi, H. Tomoo; Okada, Hirohumi; Ichimasu, Norio; Kohno, Michihiro

    2014-01-01

    Background: An increasing number of elderly patients present with intracranial aneurysms. In addition to female gender, an older age is associated with a higher risk of developing a subarachnoid hemorrhage (SAH), and these patients often fare poorly in terms of long-term outcome. It is often thought that elderly patients would especially benefit from endovascular aneurysm treatment. We assessed the clinical outcomes in elderly patients with ruptured intracranial aneurysms (RIAs) who were treated by endovascular procedures. Methods: We performed a retrospective review of a prospective database of elderly patients treated with coil embolization for RIAs. The clinical outcomes were assessed using the modified Glasgow Outcome Scale. The rates of procedural complications and adverse events were also recorded. Results: During a period of 5 years, 162 patients with 183 intracranial aneurysms were treated in our hospital by means of an endovascular approach. Among them, 51 patients (31.5%) with a ruptured aneurysm were aged 70 years or older. These patients aged 70-91 years (mean age, 74 years) were treated by coil embolization for RIAs. Among them, seven had a Hunt and Hess (HH) grade of I or II, 42 had an HH grade of III or IV, and 2 had an HH grade of V. Endovascular treatment resulted in 32 complete occlusions (62.7%), 15 neck remnants (22%), and 4 body fillings (7.9%). Procedural complications occurred in five patients (9.8%). The outcomes were good or excellent in 17 patients (33.3%). Three patients (5.8%) who died had an HH grade of IV or V. Rebleeding occurred during follow-up in one patient (1.9%). Conclusions: Coil embolization of intracranial aneurysms is safe and effective in the elderly. However, the morbidity and mortality rates are higher in patients with high HH grades. This finding suggests that the timing of treatment should be based on the patient's initial clinical status. PMID:25101199

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

    PubMed

    Todorov, Mina; Hernandez, Diego

    2013-07-01

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

  5. 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.

  6. Extracellular Oxidoreduction Potential Modifies Carbon and Electron Flow in Escherichia coli

    PubMed Central

    Riondet, Christophe; Cachon, Rémy; Waché, Yves; Alcaraz, Gérard; Diviès, Charles

    2000-01-01

    Wild-type Escherichia coli K-12 ferments glucose to a mixture of ethanol and acetic, lactic, formic, and succinic acids. In anoxic chemostat culture at four dilution rates and two different oxidoreduction potentials (ORP), this strain generated a spectrum of products which depended on ORP. Whatever the dilution rate tested, in low reducing conditions (−100 mV), the production of formate, acetate, ethanol, and lactate was in molar proportions of approximately 2.5:1:1:0.3, and in high reducing conditions (−320 mV), the production was in molar proportions of 2:0.6:1:2. The modification of metabolic fluxes was due to an ORP effect on the synthesis or stability of some fermentation enzymes; thus, in high reducing conditions, lactate dehydrogenase-specific activity increased by a factor of 3 to 6. Those modifications were concomitant with a threefold decrease in acetyl-coenzyme A (CoA) needed for biomass synthesis and a 0.5- to 5-fold decrease in formate flux. Calculations of carbon and cofactor balances have shown that fermentation was balanced and that extracellular ORP did not modify the oxidoreduction state of cofactors. From this, it was concluded that extracellular ORP could regulate both some specific enzyme activities and the acetyl-CoA needed for biomass synthesis, which modifies metabolic fluxes and ATP yield, leading to variation in biomass synthesis. PMID:10633094

  7. 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.

  8. 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.

  9. 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.

  10. Locally modified QUICK scheme for highly convective 2-D and 3-D flows

    NASA Astrophysics Data System (ADS)

    Leonard, B. P.

    The positive and negative aspects of the QUICK scheme are discussed. QUICK is used in the bulk of the flow domain; however, when the local curvature of the convected variable exceeds a preset value, the algorithm switches to exponential upwinding or other compatible interpolation. Results are presented for the purely convective oblique-step test. A comparison is made between the sharp monotonic EULER-QUICK results and first-, second-, and third-order upwinding.

  11. Simulation and augmented reality in endovascular neurosurgery: lessons from aviation.

    PubMed

    Mitha, Alim P; Almekhlafi, Mohammed A; Janjua, Major Jameel J; Albuquerque, Felipe C; McDougall, Cameron G

    2013-01-01

    Endovascular neurosurgery is a discipline strongly dependent on imaging. Therefore, technology that improves how much useful information we can garner from a single image has the potential to dramatically assist decision making during endovascular procedures. Furthermore, education in an image-enhanced environment, especially with the incorporation of simulation, can improve the safety of the procedures and give interventionalists and trainees the opportunity to study or perform simulated procedures before the intervention, much like what is practiced in the field of aviation. Here, we examine the use of simulators in the training of fighter pilots and discuss how similar benefits can compensate for current deficiencies in endovascular training. We describe the types of simulation used for endovascular procedures, including virtual reality, and discuss the relevant data on its utility in training. Finally, the benefit of augmented reality during endovascular procedures is discussed, along with future computerized image enhancement techniques.

  12. Modified Cr valence in symmetric oxygen ion conducting half cells with ion flow

    NASA Astrophysics Data System (ADS)

    Finsterbusch, Martin; Lussier, Alexandre; Negusse, Ezana; Idzerda, Yves

    2010-03-01

    The degradation mechanisms in ion conducting materials, including solid oxide fuel cells (SOFC), are still of high interest in current energy research, especially with regards to material and interface stability, fuel impurities and impurities originating from sealing or interconnect materials. A common practice is the use of symmetric half-cells (e.g. cathode/electrolyte/cathode) to determine interface stability via cross section Energy Dispersive x-ray Spectroscopy line scans and overpotential magnitude and degradation via AC-impedance spectroscopy. Using these electrically driven half-cells, we have developed a new method to directly measure degradation due to oxygen ion flow through ion conducting materials and their associated interface structures. By using X-ray absorption spectroscopy of cells before and after oxygen ion flow (800 C for 100 hours), we determined that the valence state of Cr that migrated from a metallic interconnect into the porous cathode changes in valence from +3 (Cr2O3) to +6 (CrO3), depending on the direction of the oxygen ion flow. This observation is strong evidence of the influence of the oxygen ion flux on the degradation mechanisms of ion conducting materials.

  13. 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

  14. 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.

  15. 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.

  16. 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

  17. 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.

  18. 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

  19. 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

  20. 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.

  1. Endovascular Repair of Abdominal Aortic Aneurysms

    PubMed Central

    Chaikof, Elliot L.; Lin, Peter H.; Brinkman, William T.; Dodson, Thomas F.; Weiss, Victor J.; Lumsden, Alan B.; Terramani, Thomas T.; Najibi, Sasan; Bush, Ruth L.; Salam, Atef A.; Smith, Robert B.

    2002-01-01

    Objective The impact of co-morbid conditions on early and late clinical outcomes after endovascular treatment of abdominal aortic aneurysm (AAA) was assessed in concurrent cohorts of patients stratified with respect to risk for intervention. Summary Background Data As a minimally invasive strategy for the treatment of AAA, endovascular repair has been embraced with enthusiasm for all prospective patients who are suitable anatomical candidates because of the promise of achieving a durable result with a reduced risk of perioperative morbidity and mortality. Methods From April 1994 to March 2001, endovascular AAA repair was performed in 236 patients using commercially available systems. A subset of patients considered at increased risk for intervention (n = 123) were categorized, as such, based on a preexisting history of ischemic coronary artery disease, with documentation of myocardial infarction (60%) or congestive heart failure (35%), or due to the presence of chronic obstructive disease (21%), liver disease, or malignancy. Results Perioperative mortality (30-day) was 6.5% in the increased-risk patients as compared to 1.8% among those classified as low risk (P = NS). There was no difference between groups in age (74 ± 9 years vs. 72 ± 6 years; mean ± SD), surgical time (235 ± 95 minutes vs. 219 ± 84 minutes), blood loss (457 ± 432 mL vs. 351 ± 273 mL), postoperative hospital stay (4.8 ± 3.4 days vs. 4.0 ± 3.9 days), or days in the ICU (1.3 ± 1.8 days vs. 0.5 ± 1.6 days). Patients at increased risk of intervention had larger aneurysms than low-risk patients (59 ± 13 mm vs. 51 ± 14 mm;P < .05). Stent grafts were successfully implanted in 116 (95%) increased-risk versus 107 (95%) low-risk patients (P = NS). Conversion rates to open operative repair were similar in increased-risk and low-risk groups at 3% and 5%, respectively. The initial endoleak rate was 22% versus 20%, based on the first CT performed (either at discharge or 1 month;P = NS). To date

  2. Determinants of Effective Cooling during Endovascular Hypothermia

    PubMed Central

    Lyden, Patrick; Ernstrom, Karin; Cruz-Flores, Salvador; Gomes, Joao; Grotta, James; Mullin, Anthony; Rapp, Karen; Raman, Rema; Wijman, Christine; Hemmen, Thomas

    2012-01-01

    Therapeutic hypothermia is a promising neuroprotective therapy with multiple mechanisms of action. We demonstrated the feasibility of thrombolysis combined with endovascular hypothermia, but not all patients achieved effective cooling. We sought to identify the factors that determined effective cooling. Methods In 26 patients who underwent endovascular hypothermia we computed 4 measures of effective cooling: time to reach target; Area-Under-the-Curve (AUC) 34 ratio; AUC-34; and AUC-35. Using multivariate regression, we examined the effects of age, weight, starting temperature, body mass index, body surface area (BSA) , gender, shivering, and total meperidine dose on the 4 outcome measures. Results In univariate analyses, all 4 outcome measures were significantly influenced by BSA (p<0.01 in all univariate analyses). Time to reach target temperature was quicker in older patients (p<0.01). Shivering and meperidine dose were highly intercorrelated (r=0.6, p<0.01) and both marginally influenced all 4 outcome measures. In multivariate analysis, AUC ratio and time to reach target temperature were significantly influenced by BSA (p<0.01) and meperidine (p<0.05); AUC-34 was influenced only by BSA (p<0.01). The AUC- 35 was influenced by BSA (p<0.01), shivering, and total meperidine dose (p<0.05). Conclusions The most important determinant of effective cooling during endovascular hypothermia is BSA; larger patients are more difficult to cool and maintain in therapeutic range. Older patients cool more quickly. Shivering was well controlled by the combination of meperidine, buspirone, and surface counter-warming and only minimally influenced cooling effectiveness. Future trials of therapeutic hypothermia may include added measures to cool larger patients more effectively. PMID:22466971

  3. 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).

  4. Congestion phenomenon analysis and delayed-feedback control in a modified coupled map traffic flow model containing the velocity difference

    NASA Astrophysics Data System (ADS)

    Fang, Ya-Ling; Shi, Zhong-Ke; Cao, Jin-Liang

    2015-06-01

    Based on the coupled map car-following model which was presented by Konishi et al. (1999), a modified coupled map car-following model is proposed. Specifically, the velocity difference between two successive vehicles is included in the model. The stability condition is given for the change of the speed of the preceding vehicle on the base of the control theory. We derive a condition under which the traffic jam never occurs in our model. Furthermore, in order to suppress traffic jams, we use static and dynamic version of decentralized delayed-feedback control for each vehicle, respectively, and provide a systematic procedure for designing the controller. In addition, the controller of each vehicle does not include any other vehicle information in real traffic flows.

  5. 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

  6. 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.

  7. 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.

  8. [The endovascular correction of aortic coarctation].

    PubMed

    Barkov, E D; Silin, V A; Sukhov, V K

    1992-03-01

    The endovascular balloon dilatation of the aorta coarctation performed on indications and at the optimal terms is the radical correction of the defect with a pronounced positive effect in 90% of 43 patients. No aneurysms and restenoses were found. Retained collaterals allow avoidance of the abdominal syndrome and paradoxical hypertension. Contraindications for catheter angioplasty are thought to include agenesia or considerable hypoplasia of the aorta, the absence of the aorta lumen in the zone of coarctation, its considerable length and the presence of prestenotic aneurysms. A short and noncomplicated postoperative period makes the method sufficiently economical.

  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. 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

  11. 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

  12. Aortocaval Fistula: Is Endovascular Repair the Preferred Solution?

    PubMed Central

    Orion, Kristine Clodfelter; Beaulieu, Robert J.; Black, James H.

    2016-01-01

    Background To compare outcomes of open and endovascular repair of aortocaval fistulas (ACFs) in the setting of abdominal aortic aneurysms (AAAs). Methods A literature review was undertaken on Pubmed from 1999 to 2014 to identify reported cases of both endovascular and open repair of ACF, including the index case, presented here. Primary outcomes for endovascular repair were: complications, presence of endoleak, and death. Primary outcomes for open repair were: complications and death. Results Forty articles were reviewed with a total of 67 patients, including the index case. Endovascular approach was used in 26 patients (39%). Endoleaks were present in 50%, whereas similarly 46% of patients had a reported complication. Five deaths (19%) occurred in the endovascular group. Open repair was performed in 41 cases (61%). The rate of complication and the death in open repair were 36% and 12%, respectively (P = 0.327 and P = 0.910, respectively) compared with endovascular. Mean follow-up was 7.7 months for the endovascular group and 8.5 months in the open group. Conclusions Previous demonstrations of high morbidity and mortality with open repair of ACF in the setting of AAA have motivated endovascular approaches. However, endoleaks are a significant problem and were present in 50% of ACF cases. The continued presence of an endoleak in the setting of an ACF may result in persistence of the ACF, unlikely thrombosis of the endoleak, and continued sac enlargement. Endovascular repair presents theoretical benefit, yet is not associated with a reduced rate of complication or death versus open repair in this contemporary review. PMID:26597238

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

    NASA Technical Reports Server (NTRS)

    Paxson Daniel E.; Nalim, M. Razi

    1998-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1983-01-01

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

  15. 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

  16. Beyond the use of modifiers in selective alkyne hydrogenation: silver and gold nanocatalysts in flow mode for sustainable alkene production.

    PubMed

    Vilé, Gianvito; Pérez-Ramírez, Javier

    2014-11-21

    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. PMID:25132414

  17. Flow-induced vibration and instability of embedded double-walled carbon nanotubes based on a modified couple stress theory

    NASA Astrophysics Data System (ADS)

    Ke, Liao-Liang; Wang, Yue-Sheng

    2011-03-01

    Vibration and instability of fluid-conveying double-walled carbon nanotubes (DWNTs) are investigated in this paper based on the modified couple stress theory and the Timoshenko beam theory. The microstructure-dependent Timoshenko beam model, which contains a material length scale parameter and can take the size effect into account, is employed. The Poisson's ratio effect is also included in this model. The surrounding elastic medium is described as the Winkler model characterized by the spring. The higher-order governing equations and boundary conditions are derived by using Hamilton's principle. The differential quadrature (DQ) method is employed to discretize the governing equations, which are then solved to obtain the resonant frequencies of fluid-conveying DWNTs with different boundary conditions. A detailed parametric study is conducted to study the influences of length scale parameter, Poisson's ratio, spring constant, aspect ratio of the DWNTs, velocity of the fluid and end supports on the vibration and flow-induced instability of DWNTs. Results show that the imaginary component of the frequency and the critical flow velocity of the fluid-conveying DWNTs increase with increase in the length scale parameter.

  18. 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.

  19. Emergency rescue endovascular stent grafting of ascending aorta to relieve life-threatening coronary obstruction in a case of acute aortic dissection.

    PubMed

    Tauchi, Yuuya; Tanioka, Hideki; Kondoh, Haruhiko; Satoh, Hisashi; Matsuda, Hikaru

    2014-12-01

    Myocardial ischemia associated with acute aortic dissection is frequently a fatal complication, and the emergent management still remains a challenge. We report a patient with life-threatening myocardial ischemia due to acute aortic dissection managed by rescue stent grafting of the ascending aorta. Coronary blood flow improved immediately with this endovascular procedure, hemodynamic status was ameliorated dramatically, followed by uneventful open repair.

  20. [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.

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

    PubMed Central

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

    1979-01-01

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

  2. Evidence for modified transport due to sheared E x B flows in high-temperature plasmas

    SciTech Connect

    Groebner, R.J.; Burrell, K.H.; Austin, M.E.

    1994-11-01

    Sheared mass flows are generated in many fluids and are often important for the dynamics of instabilities in these fluids. Similarly, large values of the E x B velocity have been observed in magnetic confinement machines and there is theoretical and experimental evidence that sufficiently large shear in this velocity may stabilize important instabilities. Two examples of this phenomenon have been observed in the DIII-D tokamak. In the first example, sufficient heating power can lead to the L-H transition, a rapid improvement in confinement in the boundary layer of the plasma. For discharges with heating power close to the threshold required to get the transition, changes in the edge radial electric field are observed to occur prior to the transition itself. In the second example, certain classes of discharges with toroidal momentum input from neutral beam injection exhibit a further improvement of confinement in the plasma core leading to a regime called the VH-mode. In both examples, the region of improved confinement is characterized by an increase of shear in the radial electric field E{sub r}, reduced levels of turbulence and increases in gradients of temperatures and densities. These observations are consistent with the hypothesis that the improved confinement is caused by an increase in shear of the E x B velocity which leads to a reduction of turbulence. For the VH-mode, the dominant term controlling E{sub r} is the toroidal rotation v{sub {phi}}, indicating that the E{sub r} profile is controlled by the source and transport of toroidal momentum.

  3. 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.

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

    SciTech Connect

    Duncan, Joanne P.

    2011-04-29

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

  5. 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.

  6. Endovascular treatment of abdominal aortic aneurysms

    PubMed Central

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

    2014-01-01

    Patients with abdominal aortic aneurysms (AAAs) are usually treated with endovascular aneurysm repair (EVAR), which has become the standard of care in many hospitals for patients with suitable anatomy. Clinical evidence indicates that EVAR is associated with superior perioperative outcomes and similar long-term survival compared with open repair. Since the randomized, controlled trials that provided this evidence were conducted, however, the stent graft technology for infrarenal AAA has been further developed. Improvements include profile downsizing, optimization of sealing and fixation, and the use of low porosity fabrics. In addition, imaging techniques have improved, enabling better preoperative planning, stent graft placement, and postoperative surveillance. Also in the past few years, fenestrated and branched stent grafts have increasingly been used to manage anatomically challenging aneurysms, and experiments with off-label use of stent grafts have been performed to treat patients deemed unfit or unsuitable for other treatment strategies. Overall, the indications for endovascular management of AAA are expanding to include increasingly complex and anatomically challenging aneurysms. Ongoing studies and optimization of imaging, in addition to technological refinement of stent grafts, will hopefully continue to broaden the utilization of EVAR. PMID:24343568

  7. 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

  8. Endovascular neurointervention success and complication rates in the first year of independent practice in a suburban hospital setup

    PubMed Central

    Kumar, Subhash

    2014-01-01

    Context: Endovascular neurointervention (interventional neuroradiology) is a highly demanding science requiring deep understanding of disease, anatomy, clinical skills and manual dexterity, consequently with a long learning curve and thus posing significant challenges to a physician entering new into the competitive arena. Aim: To evaluate the procedural success, complications and outcome in the first year of independent endovascular neurointervention practice in a suburban hospital. Materials and Methods: Retrospective analysis of prospectively maintained data of all diagnostic and therapeutic neurointerventional cases performed by the author between the period of January 02, 2012 and December 31, 2012. Results: A total of 61 procedures were performed. The performance success rate of the diagnostic procedures was 100% (38/38) and that of therapeutic procedures was 82.6% (19/23). The periprocedural complication rates were nil and 13%, respectively, for diagnostic and therapeutic procedures. The 3-month patient outcome for therapeutic procedures was good outcome (Modified Rankin Scale <2) in 87% cases (20/23), and poor outcome in 13% (2 dead and 1 debilitated with Modified Rankin Scale of 3). Conclusion: For a well-trained endovascular neurointerventionalist, the first year of practice had high procedural success rate and acceptable complication with patient outcome rates comparable to the existing literature. PMID:24741242

  9. 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.

  10. 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.

  11. 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.

  12. Applicability of Modified Drift Flux Model for Bubbly Flow in 2-D/3-D Rectangular Box With Various Kinds of Obstacles

    SciTech Connect

    Tatsuya Matsumoto; Akihiro Uchibori; Ryo Akasaka; Toshinori Seki; Shyuji Kaminishi; Koji Morita; Kenji Fukuda

    2002-07-01

    In order to develop analytical tools for the analyses of multi dimensional two-phase flow in channels with obstacles, the modified drift flux model has been applied. Numerical simulations of multi dimensional gas-liquid two-phase flow in a channel, with some kinds of obstacles inserted to simulate a simple sub-channel in the fuel bundle, were carried out. Analytical results were compared with experiments, to show the validity of the modified drift flux model. Experiments were carried out with using an apparatus of 2-D/3-D rectangular box with a perforated plate or a horizontal plate with slit hole or a vertical rod inserted. Nitrogen gas-water adiabatic two phase flow was circulated in the box. The apparatus was made of acrylic resin plates and be able to make the flow inside visualized. Two-phase flow pattern were recorded with a high-speed video camera and the mass flow rate of nitrogen gas was measured with a digital gas-mass flow meter. Comparisons between the experimental results and the numerical ones showed good agreements, thus it was verified the model would be applied for predicting flows in more complex geometry with obstacles. (authors)

  13. 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.

  14. 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...

  15. Developing practice recommendations for endovascular revascularization for acute ischemic stroke

    PubMed Central

    Lazzaro, Marc A.; Alexandrov, Andrei V.; Darkhabani, Ziad; Edgell, Randall C.; English, Joey; Frei, Donald; Jamieson, Dara G.; Janardhan, Vallabh; Janjua, Nazli; Janjua, Rashid M.; Katzan, Irene; Khatri, Pooja; Kirmani, Jawad F.; Liebeskind, David S.; Linfante, Italo; Nguyen, Thanh N.; Saver, Jeffrey L.; Shutter, Lori; Xavier, Andrew; Yavagal, Dileep; Zaidat, Osama O.

    2012-01-01

    Guidelines have been established for the management of acute ischemic stroke; however, specific recommendations for endovascular revascularization therapy are lacking. Burgeoning investigation of endovascular revascularization therapies for acute ischemic stroke, rapid device development, and a diverse training background of the providers performing the procedures underscore the need for practice recommendations. This review provides a concise summary of the Society of Vascular and Interventional Neurology endovascular acute ischemic stroke roundtable meeting. This document was developed to review current clinical efficacy of pharmacologic and mechanical revascularization therapy, selection criteria, periprocedure management, and endovascular time metrics and to highlight current practice patterns. It therefore provides an outline for the future development of multisociety guidelines and recommendations to improve patient selection, procedural management, and organizational strategies for revascularization therapies in acute ischemic stroke. PMID:23008406

  16. [Abdominal aortic aneurysm. Endovascular treatment with fenestrated endoprothesis].

    PubMed

    Rostagno, Román; Cesareo, Vicente; García-Mónaco, Ricardo; Peralta, Oscar; Domenech, Alberto; Bracco, Daniel

    2008-01-01

    Endovascular treatment of the abdominal aortic aneurysm is consider an alternative to open surgery for high risk patients. Its goal is to exclude the aneurysm from the circulation by using an endoprothesis introduced from a femoral approach. Patients must be strictly selected to avoid possible complications. The most frequent limitation is related to anatomic contraindications such as visceral arteries involved in the aneurysm. Fenestrated endograft have been recently developed to allow endovascular treatment when anatomic features contraindicate classic endovascular procedures. Fenestrated endograft have holes that match with the origin of the visceral arteries maintaining its potency. In this paper we report the endovascular treatment of an abdominal aortic aneurysm by using a fenestrated endoprothesis in a patient whose left renal artery is originated from the aneurysm.

  17. 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

  18. [Childhood transverse sinus dural arteriovenous fistula treated with endovascular and direct surgery: a case report].

    PubMed

    Niizuma, Kuniyasu; Sakata, Hiroyuki; Koyama, Shinya; Kon, Hiroyuki; Chonan, Masashi; Sasaki, Tatsuya; Nishijima, Michiharu; Ezura, Masayuki; Tominaga, Teiji

    2012-11-01

    Infantile dural arteriovenous fistula is a rare cerebrovascular malformation carrying a poor prognosis with an anatomic cure of only 9%. Endovascular embolization is mainly selected to treat this entity, aiming to obtain normal development of the patients. We present a case of a 20-month-old girl with epilepsy. Digital subtraction angiography revealed a dural arteriovenous fistula involving the right transverse sinus. The arteriovenous fistula was fed by multiple dural branches from the middle meningeal, occipital, meningohypophyseal, and anteroinferior cerebellar arteries. The right transverse sinus was transvenously embolized with platinum coils. Although the shunt flow remained, the patient was liberated from epilepsy. Nine months later, the patient suffered from a recurrence of epilepsy. Digital subtraction angiography demonstrated some increase in shunt flow. Right middle meningeal, occipital, posterior deep temporal, and tentorial arteries were transarterially embolized using N-butyl cyanoacrylate, followed by complete surgical resection of the right transverse sinus. The shunt flow disappeared after surgery, and her epilepsy improved significantly. Our experience suggests that the combination of endovascular and surgical treatment is effective for recurrent infantile dural arteriovenous fistula.

  19. 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.

  20. 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.

  1. Imaging After Nellix Endovascular Aneurysm Sealing: A Consensus Document.

    PubMed

    Holden, Andrew; Savlovskis, Janis; Winterbottom, Andrew; van den Ham, Leo H; Hill, Andrew; Krievins, Dainis; Hayes, Paul D; Reijnen, Michel M P J; Böckler, Dittmar; de Vries, Jean-Paul P M; Carpenter, Jeffrey P; Thompson, Matt M

    2016-02-01

    Endovascular aneurysm sealing (EVAS) using the Nellix system is a new and different method of abdominal aortic aneurysm repair. Normal postoperative imaging has unique appearances that change with time; complications also have different and specific appearances. This consensus document on the imaging findings after Nellix EVAS is based on the collective experience of the sites involved in the Nellix EVAS Global Forward Registry and the US Investigational Device Exemption Trial. The normal findings on computed tomography (CT), duplex ultrasound, magnetic resonance imaging, and plain radiography are described. With time, endobag appearances change on CT due to contrast migration to the margins of the hydrogel polymer within the endobag. Air within the endobag also has unique appearances that change over time. Among the complications after Nellix EVAS, type I endoleak usually presents as a curvilinear area of flow between the endobag and aortic wall, while type II endoleak is typically small and usually occurs where an aortic branch artery lies adjacent to an irregular aortic blood lumen that is not completely filled by the endobag. Procedural aortic injury is an uncommon but important complication that occurs as a result of overfilling of the endobags during Nellix EVAS. The optimum imaging surveillance algorithm after Nellix EVAS has yet to be defined but is largely CT-based, especially in the first year postprocedure. However, duplex ultrasound also appears to be a sensitive modality in identifying normal appearances and complications.

  2. [Endovascular treatment for cervical carotid artery aneurysm: a case report].

    PubMed

    Hattori, Yasuhiko; Sugiu, Kenji; Hishikawa, Tomohito; Tokunaga, Koji; Takahashi, Kazuya; Date, Isao

    2013-06-01

    We report here a case of cervical carotid artery aneurysm. This 37-year-old male suffered from acute neck swelling when he was taking lunch after physical work. Ultrasonography demonstrated a cervical pseudoaneurysm and a jet flow, which was blowing into the dome from the carotid artery. Angiogram revealed an aneurysm with a diameter of 3 cm at the bifurcation of the common carotid artery. Coil embolization using double-catheter technique was performed and complete occlusion of the aneurysm was obtained without any complications. The patient returned to his normal life. Cervical carotid artery aneurysms are rare and they induce pain by swelling in the neck, hoarseness, swallowing disturbance, hemorrhage, and cerebral ischemia due to embolism. In case of a cervical carotid artery aneurysm, safe and effective treatments are required and endovascular treatment should be considered. Although stent-assisted coil embolization or covered-stent placement were reported as an effective treatment for cervical aneurysms, coil embolization without using a stent was performed in this particular patient who is a young, blue-collar worker because the avoidance of long-term anti-platelet therapy was desirable. Preoperative evaluation is important to select adequate treatment. PMID:23732763

  3. Beyond the use of modifiers in selective alkyne hydrogenation: silver and gold nanocatalysts in flow mode for sustainable alkene production

    NASA Astrophysics Data System (ADS)

    Vilé, Gianvito; Pérez-Ramírez, Javier

    2014-10-01

    We report on the excellent stereo and chemoselectivity of nanosized silver and gold catalysts in the three-phase hydrogenation of acetylenic compounds under flow chemistry conditions. The materials featuring metal nanoparticles in the range of 2-21 nm were prepared by spray deposition or incipient wetness impregnation of silver nitrate and sol immobilisation of gold chloride on different carriers (Al2O3, SiO2, TiO2, and carbon), followed by activation in various atmospheres. The samples were characterised by ICP-OES, N2 sorption, XPS, HAADF-STEM, and HRTEM, and evaluated in a continuous-flow flooded-bed micro-reactor. Both metals display optimal activities for particles below 5 nm, enabling stable operation at T = 373 K and P = 10 bar. While the performance of the silver catalysts is less influenced by the support, the gold nanoparticles exhibit significant activity only when deposited on TiO2, likely due to the strong metal-support interaction. Hydrogenations of functionalised alkynes reveal that silver and gold match, and in some cases exceed, the selectivity of benchmark palladium-based catalysts. Furthermore, in contrast to Pd, the Ag and Au samples require no modifiers, which brings fundamental and practical simplifications for their understanding and large scale manufacture. Therefore, these materials could be advantageously used for the continuous production of olefinic intermediates in the fine chemical and pharmaceutical industries.We report on the excellent stereo and chemoselectivity of nanosized silver and gold catalysts in the three-phase hydrogenation of acetylenic compounds under flow chemistry conditions. The materials featuring metal nanoparticles in the range of 2-21 nm were prepared by spray deposition or incipient wetness impregnation of silver nitrate and sol immobilisation of gold chloride on different carriers (Al2O3, SiO2, TiO2, and carbon), followed by activation in various atmospheres. The samples were characterised by ICP-OES, N2 sorption

  4. 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

  5. Treatment of Hostile Proximal Necks During Endovascular Aneurysm Repair

    PubMed Central

    Navarro, Tulio Pinho; Bernardes, Rodrigo de Castro; Procopio, Ricardo Jayme; Leite, Jose Oyama; Dardik, Alan

    2014-01-01

    Endovascular aneurysm repair (EVAR) is a therapy that continues to evolve rapidly as advances in technology are incorporated into new generations of devices and surgical practice. Although EVAR has emerged as a safe and effective treatment for patients with favorable anatomy, treatment of patients with unfavorable anatomy remains controversial and is still an off-label indication for endovascular treatment with some current stent-grafts. The proximal neck of the aneurysm remains the most hostile anatomic barrier to successful endovascular repair with long-term durability. Open surgery for unfavorable necks is still considered the gold standard treatment in contemporary practice, despite the increased mortality and morbidity attributed to suprarenal cross-clamping, particularly in high-risk patients. Evolving technology may overcome the obstacles preventing endovascular treatment of unfavorable proximal neck anatomy; current approaches include purely endovascular as well as hybrid approaches, and generally include strategies that either extend the length of the short neck, move the proximal neck more proximally, or keep the short neck intact. These approaches include the use of debranching techniques, banding, chimneys, fenestrated and branched devices, filling the sac with endobags, endoanchors, and other novel devices. These newer-generation devices appear to have promising short- and midterm results. However, lack of good evidence of efficacy with long-term results for these newer approaches still precludes wide dissemination of endovascular solutions for the hostile proximal neck. PMID:26798712

  6. Treatment of Hostile Proximal Necks During Endovascular Aneurysm Repair.

    PubMed

    Navarro, Tulio Pinho; Bernardes, Rodrigo de Castro; Procopio, Ricardo Jayme; Leite, Jose Oyama; Dardik, Alan

    2014-02-01

    Endovascular aneurysm repair (EVAR) is a therapy that continues to evolve rapidly as advances in technology are incorporated into new generations of devices and surgical practice. Although EVAR has emerged as a safe and effective treatment for patients with favorable anatomy, treatment of patients with unfavorable anatomy remains controversial and is still an off-label indication for endovascular treatment with some current stent-grafts. The proximal neck of the aneurysm remains the most hostile anatomic barrier to successful endovascular repair with long-term durability. Open surgery for unfavorable necks is still considered the gold standard treatment in contemporary practice, despite the increased mortality and morbidity attributed to suprarenal cross-clamping, particularly in high-risk patients. Evolving technology may overcome the obstacles preventing endovascular treatment of unfavorable proximal neck anatomy; current approaches include purely endovascular as well as hybrid approaches, and generally include strategies that either extend the length of the short neck, move the proximal neck more proximally, or keep the short neck intact. These approaches include the use of debranching techniques, banding, chimneys, fenestrated and branched devices, filling the sac with endobags, endoanchors, and other novel devices. These newer-generation devices appear to have promising short- and midterm results. However, lack of good evidence of efficacy with long-term results for these newer approaches still precludes wide dissemination of endovascular solutions for the hostile proximal neck.

  7. 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.

  8. 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

  9. Endovascular treatment of acute ischemic stroke.

    PubMed

    Kidwell, Chelsea S; Jahan, Reza

    2015-05-01

    Endovascular therapy for acute stroke has evolved with the use of intra-arterial thrombolytics, intravenous/intra-arterial bridging strategies, and mechanical thrombectomy/aspiration devices. Despite widespread use in clinical practice, randomized trials of first-generation devices failed to demonstrate improved outcomes compared with standard care. New-generation stent retriever devices demonstrate higher rates of revascularization and clinical outcomes compared with first-generation devices. Additional randomized trials are underway and have the potential to confirm clinical efficacy of new-generation devices compared with standard care. The role of additional advanced imaging for patient selection remains unclear, and further trials are needed to demonstrate the role of these techniques for patient selection. PMID:25907913

  10. 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

  11. 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

  12. Endovascular repair of thoracic aortic aneurysm

    PubMed Central

    Akin, Ibrahim; Kische, Stephan; Rehders, Tim C.; Nienaber, Christoph A.; Rauchhaus, Mathias

    2010-01-01

    A thoracic aortic aneurysm (TAA) is a potentially life-threatening condition with structural weakness of the aortic wall, which can progress to arterial dilatation and rupture. Today, both an increasing awareness of vascular disease and the access to tomographic imaging facilitate the diagnosis of TAA even in an asymptomatic stage. The risk of rupture for untreated aneurysms beyond a diameter of 5.6 cm ranges from 46% to 74% and the two-year mortality rate is greater than 70%, with most deaths resulting from rupture. Treatment options include surgical and non-surgical repair to prevent aneurysm enlargement and rupture. While most cases of ascending aortic involvement are subject to surgical repair (partially with valve-preserving techniques), aneurysm of the distal arch and descending thoracic aorta are amenable to emerging endovascular techniques as an alternative to classic open repair or to a hybrid approach (combining debranching surgery with stent grafting) in an attempt to improve outcomes. PMID:22419919

  13. 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.

  14. 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. PMID:27583175

  15. Current endovascular treatment of infrarenal abdominal aortic aneurysms and future directions.

    PubMed

    Kokkosis, Angela A; Abramowitz, Steven; Malik, Rajesh K; Ellozy, Sharif H; Faries, Peter L; Marin, Michael L

    2012-12-01

    The paradigm in elective surgical management of infrarenal abdominal aortic aneurysms (AAAs) has quickly shifted from major open surgical repairs to less invasive, endovascular procedures. In the last few years, there have been numerous advancements to commercially available devices making the endovascular approach more attractive and efficacious. This review serves to detail the similarities, differences, advantages, and disadvantages of currently available endovascular stent-grafts as well as preview future and emerging technologies in endovascular aortic therapies.

  16. Endovascular Repair of Descending Thoracic Aortic Aneurysm

    PubMed Central

    2005-01-01

    Executive Summary Objective To conduct an assessment on endovascular repair of descending thoracic aortic aneurysm (TAA). Clinical Need Aneurysm is the most common condition of the thoracic aorta requiring surgery. Aortic aneurysm is defined as a localized dilatation of the aorta. Most aneurysms of the thoracic aorta are asymptomatic and incidentally discovered. However, TAA tends to enlarge progressively and compress surrounding structures causing symptoms such as chest or back pain, dysphagia (difficulty swallowing), dyspnea (shortness of breath), cough, stridor (a harsh, high-pitched breath sound), and hoarseness. Significant aortic regurgitation causes symptoms of congestive heart failure. Embolization of the thrombus to the distal arterial circulation may occur and cause related symptoms. The aneurysm may eventually rupture and create a life-threatening condition. The overall incidence rate of TAA is about 10 per 100,000 person-years. The descending aorta is involved in about 30% to 40% of these cases. The prognosis of large untreated TAAs is poor, with a 3-year survival rate as low as 25%. Intervention is strongly recommended for any symptomatic TAA or any TAA that exceeds twice the diameter of a normal aorta or is 6 cm or larger. Open surgical treatment of TAA involves left thoracotomy and aortic graft replacement. Surgical treatment has been found to improve survival when compared with medical therapy. However, despite dramatic advances in surgical techniques for performing such complex operations, operative mortality from centres of excellence are between 8% and 20% for elective cases, and up to 50% in patients requiring emergency operations. In addition, survivors of open surgical repair of TAAs may suffer from severe complications. Postoperative or postprocedural complications of descending TAA repair include paraplegia, myocardial infarction, stroke, respiratory failure, renal failure, and intestinal ischemia. The Technology Endovascular aortic aneurysm

  17. 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

  18. Dilatation of Common Iliac Arteries after Endovascular Infrarenal Abdominal Aortic Repair with Bell-Bottom Extension

    PubMed Central

    Telles, Gustavo José Politzer; Razuk Filho, Álvaro; Karakhanian, Walter Khegan; Saad, Paulo Fernandes; Saad, Karen Ruggeri; Park, Jong Hun; Siqueira, Leticia Cristina Dalledone; Caffaro, Roberto Augusto

    2016-01-01

    Objective Endovascular techniques to treat abdominal aortic aneurysms results in lower morbidity and mortality rates. However, dilation of the common iliac arteries prevents adequate distal sealing, which compromises the procedure success. The aim of this study is report the long-term outcomes of patients with abdominal aortic aneurysms associated with aneurysm of the common iliac artery following endovascular repair using a bifurcated bell-bottom stent graft. Methods This is a retrospective study that evaluated patients treated with bifurcated bell-bottom extension stent grafts to repair an infrarenal abdominal aortic aneurysm and who had at least one common iliac artery with dilatation > 1.5 cm for at least 12 months after the endovascular intervention. Results Thirty-eight patients with a mean age of 70.4±8.2 years were included. Stent graft placement was followed by dilation of the common iliac artery aneurysms in 35.3% of cases; endoleak and reoperation rates were 17.6% and 15.7%, respectively. Younger patients showed a higher rate of artery diameter increase following the procedure. The average arterial dilation was 16% in the first year, 29% in the second year, 57% in the third year and 95% from the fourth year until the end of follow-up. Conclusion Repair of infrarenal abdominal aortic aneurysms with bifurcated bell-bottom type stents when there is common iliac artery dilation is a good therapeutic option to preserve hypogastric flow. The rate of endoleak was 17.6%, and 15.7% of cases required reoperation. Younger patients are more likely to experience dilation of the common iliac artery after the procedure. PMID:27556314

  19. [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

  20. [Endovascular reconstruction of the infrarenal abdominal aortic aneurysm--experiences with 3 endovascular stent prosthesis systems].

    PubMed

    Zipfel, B; Biamino, G; Vogt, A; Diebold, T; Hetzer, R

    1998-01-01

    Seventeen patients were treated with endovascular stent grafts for AAA (seven Stentor, two Vanguard, three Talent and three EVT grafts). Intraoperative conversion to open procedure was necessary in three cases. One patient had open operation 24 h postoperatively for graft thrombosis. All patients had uneventful recovery. During follow-up (1-35 months) nine patients did not require reintervention. One patient had open repair for persistent endoleak: within 2 months postoperatively one midgraft endoleak, one graft limb thrombosis and one groin infection were treated. We did not observe any late complications. PMID:9931843

  1. A Case of Endovascular Treatment of Severe Graft Limb Kinking after Endovascular Abdominal Aortic Aneurysm Repair

    PubMed Central

    Shin, Jong-Beom; Park, Mi-Hwa; Jeong, Sang-Ho; Kwon, Sung Woo; Shin, Sung-Hee; Woo, Seong-Ill; Park, Sang-Don

    2016-01-01

    Endovascular aneurysm repair (EVAR) has been recommended as an alternative to open aneurysm repair. The risk of severe perioperative complications is lower than that in open surgical repair; however, late complications are more likely. After EVAR, regular yearly surveillance by duplex ultrasonography or computed tomography is recommended. We report the case of a 67-year-old man with a severely kinked left iliac branch of the stent graft 10 years after EVAR. He had not undergone regular follow-up during the last 4 years. We realigned the endograft kink by percutaneous transluminal angioplasty. PMID:27051658

  2. Endovascular treatment of tiny ruptured anterior communicating artery aneurysms

    PubMed Central

    Tsutsumi, Masanori; Aikawa, Hiroshi; Onizuka, Masanari; Kodama, Tomonobu; Nii, Kouhei; Matsubara, Shuko; Iko, Minoru; Etou, Housei; Sakamoto, Kimiya

    2008-01-01

    Introduction Because of its high complication rate, the endovascular treatment (EVT) of anterior communicating artery (ACoA) aneurysms less than 3 mm in maximum diameter remains controversial. We evaluated EVT of tiny ruptured ACoA aneurysms with Guglielmi detachable coils (GDCs). Methods We treated 19 ruptured ACoA aneurysms with a maximum diameter of ≤3 mm with GDCs. The pretreatment Hunt and Hess score was grade 1 in four patients, grade 2 in six, grade 3 in six, and grade 4 in three. The patients were clinically assessed before and after treatment and with multiple angiographic follow-up studies. Results All EVTs were successful; there were no aneurysm perforations or any other treatment-related complications. In five patients older than 80 years the transfemoral approach was difficult, and the direct carotid approach was used. Complete and near-complete occlusion was achieved in 16 patients (84.2%) and 3 patients (15.8%), respectively. Of the 19 patients, 16 (84.2%) were followed angiographically for a median of 38.5 months (range 16–72 months). None demonstrated recanalization of the aneurysm requiring additional treatment. In 15 patients (78.9%) the final outcome was good (modified Rankin scale, mRS, score 0–2), and 3 patients (15.8%) died or suffered severe disability (mRS score 4–6). None of 18 patients who were followed clinically for a median of 39.5 months (range 17–84 months) experienced rebleeding. Conclusion Even tiny ruptured ACoA aneurysms can be safely treated by EVT by expert neurointerventionalists using advanced techniques. PMID:18330519

  3. 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

  4. 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

  5. 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

  6. 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

  7. Evolving Role of Endovascular Treatment of Acute Ischemic Stroke

    PubMed Central

    del Zoppo, Gregory J.

    2014-01-01

    The perceived advantages of endovascular treatment for acute ischemic stroke in terms of recanalization, the multimodal and targeted approaches, and perhaps the more permissive rules on devices than on medications for their licensing favored the assumption that endovascular treatment is superior to intravenous thrombolysis for acute treatment of ischemic stroke, and its adoption in more advanced stroke centers. However, this assumption has been questioned by recent clinical trial experience showing that endovascular treatment is not superior to intravenous thrombolysis. The new evidence has changed the perception and the importance of conducting randomized trials in this area. This summary examines the background and outcomes of the latest experience with endovascular techniques in acute stroke treatment based on historical data. The new challenge is how to study the latest generation of devices called stent retrievers, which are faster in recanalizing and easier to use, in selected patients with acute ischemic stroke. In the meantime, the available evidence does not provide support for the use of endovascular treatment of acute ischemic stroke in clinical practice. PMID:24258466

  8. 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

  9. 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.

  10. 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)

  11. 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.

  12. 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

  13. 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.

  14. [Endovascular treatment of abdominal aortic aneurysms].

    PubMed

    Hatlinghus, S; Dale, L G; Nordby, A; Aadahl, P; Lundbom, J; Saether, O D; Myhre, H O

    1996-02-28

    Eight patients, six men and two women (mean age 67.3 years) were treated for infrarenal abdominal aortic aneurysm by endovascular technique. A bifurcated graft (Mialhe Stentor, Min Tec, France) was used in all cases. The introducing system, with an 18 French diameter, is inserted through an arteriotomy in the common femoral artery. The proximal end of the main part of the graft is placed just distal to the renal arteries, and includes one graft limb, which is placed in the iliac artery on the ipsilateral side. The contralateral graft limb is introduced into a short limb of the main graft through a 10 French introducer, using Seldinger-technique, from the contralateral common femoral artery. All the implantations were successful from both a technical and a clinical point of view. All patients except one were mobilized on the first day after operation and received a normal diet. A thorough preoperative evaluation of the patient with regard to selection of the right size of the implant is necessary, and the implantation must be performed with great attention to technical details. PMID:8644071

  15. Endovascular treatment of coarctation and related aneurysms.

    PubMed

    Galiñanes, E L; Krajcer, Z

    2014-06-11

    Today,surgical repair has almost doubled the 30year survival rate in patients with coarctation of the aorta (CoA), and 72% to 98% of patients now reach adulthood. Possible late complications include malignant hypertension, left ventricular dysfunction, aortic valve dysfunction, recurrent CoA, and aneurysm formation with risk of rupture. Treating postoperative CoA-related aneurysms with observation alone is associated with a mortality rate of 36%, compared with 9% for surgical repair. Even in the best surgeons' hands, aortic surgery has associated complications, and the complexity of reoperative surgery makes the risks substantially greater. For patients with CoA-related aneurysm, endovascular treatment constitutes a good alternative to reoperative surgery because it poses a lower risk of morbidity and mortality. Implanting an endograft has been shown to be successful in treating CoA and related aneurysms, producing excellent intermediate outcomes and minimal morbidity and mortality. Despite evidence that using covered stents improves outcomes, the superiority of any particular stent type has yet to be established. With a variety of endografts available, the decision of which stent to use depends on anatomy, availability, and operator preference.

  16. 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

  17. 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

  18. Critical care guidelines on the endovascular management of cerebral vasospasm.

    PubMed

    Kimball, Matthew M; Velat, Gregory J; Hoh, Brian L

    2011-09-01

    Cerebral vasospasm and delayed cerebral ischemia account for significant morbidity and mortality after aneurysmal subarachnoid hemorrhage. While most patients are managed with triple-H therapy, endovascular treatments have been used when triple-H treatment cannot be used or is ineffective. An electronic literature search was conducted to identify English language articles published through October 2010 that addressed endovascular management of vasospasm. A total of 49 articles were identified, addressing endovascular treatment timing, intra-arterial treatments, and balloon angioplasty. Most of the available studies investigated intra-arterial papaverine or balloon angioplasty. Both have generally been shown to successfully treat vasospasm and improve neurological condition, with no clear benefit from one treatment compared with another. There are reports of complications with both therapies including vessel rupture during angioplasty, intracranial hypertension, and possible neurotoxicity associated with papaverine. Limited data are available evaluating nicardipine or verapamil, with positive benefits reported with nicardipine and inconsistent benefits with verapamil. PMID:21761272

  19. 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

  20. 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.

  1. 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

  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. Hybrid Endovascular Repair in Aortic Arch Pathologies: A Retrospective Study

    PubMed Central

    Ma, Xiaohui; Guo, Wei; Liu, Xiaoping; Yin, Tai; Jia, Xin; Xiong, Jiang; Zhang, Hongpeng; Wang, Lijun

    2010-01-01

    The aortic arch presents specific challenges to endovascular repair. Hybrid repair is increasingly evolving as an alternative option for selected patients, and promising initial results have been reported. The aim of this study was to introduce our experiences and evaluate mid-term results of supra aortic transpositions for extended endovascular repair of aortic arch pathologies. From December 2002 to January 2008, 25 patients with thoracic aortic aneurysms and dissections involving the aortic arch were treated with hybrid endovascular treatment in our center. Of the 25 cases, 14 were atherosclerotic thoracic aortic aneurysms and 11 were thoracic aortic dissection. The hybrid repair method included total-arch transpositions (15 cases) or hemi-arch transpositions (10 cases), and endovascular procedures. All hybrid endovascular procedures were completed successfully. Three early residual type-I endoleaks and one type-II endoleak were observed. Stroke occurred in three patients (8%) during the in-hospital stage. The perioperative mortality rate was 4%; one patients died post-operatively from catheter related complications. The average follow-up period was 15 ± 5.8 months (range, 1–41 months). The overall crude survival rate at 15 months was 92% (23/25). During follow-up, new late endoleaks and stent-raft related complications were not observed. One case (4%) developed a unilateral lower limb deficit at 17 days and was readmitted to hospital. In conclusion, the results are encouraging for endovascular aortic arch repair in combination with supra-aortic transposition in high risk cases. Aortic endografting offers good mid-term results. Mid-term results of the hybrid approach in elderly patients with aortic arch pathologies are satisfying. PMID:21151464

  4. Effect of radioactivity on stent-graft incorporation after endovascular treatment of aneurysms: An animal study.

    PubMed

    Lerouge, Sophie; Raymond, Jean; Schloesser, Klaus; Gaboury, Louis; Soulez, Gilles

    2006-12-01

    Poor stent-graft (SG) incorporation into the vessel wall, following endovascular repair of abdominal aortic aneurysms (EVAR), can lead to endoleaks and SG migration. Low-dose radiation can prevent aneurysm recurrence after coil embolization, and has been associated with a "paradoxical" increase in neointima formation after stenting in a few studies. It was hypothesized that in situ beta radiation emitted from SG could improve its incorporation by preventing the persistence of circulating channels between the implant and the vessel wall and increasing neointima formation around the SG. Phosphorus 32 ((32)P, 200 or 400 kBq per SG (n = 6 each)) was ion implanted on the external surface of balloon-expandable SGs. Twelve radioactive and six non-radioactive SGs were deployed in iliac arteries of nine Mongrel dogs. Neointima formation inside the graft and the persistence of circulating flow through an artificial groove created during the endovascular procedure were assessed by follow-up imaging and by blinded, computerized histomorphometric analysis after animal sacrifice at 3 months. Occlusion occurred in four radioactive SGs. A lesser number of patent grooves was observed along high-activity SGs than along control SGs (1/3 versus 4/4). No difference in neointima formation was observed in radioactive and non-radioactive SGs. Alteration of external graft surface was observed after ion implantation. Ion implantation of (32)P on SGs does not seem to be a viable strategy to improve incorporation and prevent type-I endoleak after EVAR.

  5. 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

  6. 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.

  7. Endovascular Aortic Stenting in Patients with Chronic Traumatic Aortocaval Fistula

    PubMed Central

    2013-01-01

    This study aimed to present the treatment of a case of delay presenting of traumatic aortocaval fistula (ACF) and its effect on hemodynamic problem. A 59-year-old man was admitted to our hospital with heart failure due to a 41-year-old traumatic ACF. ACF closure was performed by endovascular aortic stenting. His hospital course after procedure was complicated by severe bradycardia and torsades de pointes and excessive diuresis. We concluded the endovascular technique provided an attractive alternative to open surgical methods for repair of chronic ACF. However, in chronic cases, complications such as severe bradycardia (Nicoladoni-Branham sign) and excessive diuresis must be anticipated. PMID:24386026

  8. Endovascular Repair of a Secondary Aorto-Appendiceal Fistula

    SciTech Connect

    Tse, Donald M. L.; Thompson, Andrew R. A.; Perkins, Jeremy; Bratby, Mark J.; Anthony, Susan; Uberoi, Raman

    2011-10-15

    Aortoenteric fistula (AEF) is an uncommon but serious complication occurring after aortic surgery and may occur at any site in the gastrointestinal tract, with the duodenum being the most common. Conventional surgical repair of secondary AEF has high mortality, whereas endovascular repair has emerged as an alternative treatment despite concerns about persistent or recurrent infection. We report the case of a 91-year old man who was admitted with rectal bleeding from an aorto-appendiceal fistula 9 years after open abdominal aortic aneurysm repair. This rare site for AEF was diagnosed on computed tomography, and we present the first case of endovascular treatment of this uncommon complication.

  9. 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

  10. Iliac artery kinking with endovascular therapies: technical considerations.

    PubMed

    Dawson, David L; Hellinger, Jeffrey C; Terramani, Thomas T; Najibi, Sasan; Martin, Louis G; Lumsden, Alan B

    2002-07-01

    Iliac artery tortuosity should be considered when planning endovascular interventions from a femoral approach. Stiff guide wires across tortuous iliac segments can introduce foreshortening and temporary kinking. Recognition of this phenomenon and its implications is important when making anatomic measurements before endovascular device placement, when assessing iliac runoff, and when considering adjunctive procedures after aortoiliac interventions. Two illustrative cases of external iliac artery kinking are presented, one during an abdominal aortic aneurysm endograft procedure and another encountered during stent placement in an external iliac artery dissection. In both cases, the temporary nature of the deformity was recognized, avoiding unnecessary additional intervention. PMID:12119333

  11. Endovascular treatment of the nutcracker syndrome: report of two cases.

    PubMed

    Baldi, Sebastián; Rabellino, Martín; Zander, Tobias; González, Gabriela; Maynar, Manuel

    2011-12-01

    The nutcracker syndrome (NS) is a rare condition characterized by the entrapment of the left renal vein (LRV) between the superior mesenteric artery (SMA) and the aorta. Clinically, it presents with flank pain, hematuria, and symptoms of pelvic venous congestion. Several surgical techniques have been described including left renal vein (LRV) transposition, autotransplantation, LRV bypass, superior mesenteric artery (SMA) transposition, gonadocaval bypass and nephrectomy. More recently, endovascular stenting of the renal vein has been proposed. We present two patients with NS who were successfully managed endovascularly, providing satisfactory mid-term clinical and imaging results.

  12. Modified Brinkman equation for a free flow problem at the interface of porous surfaces: The Cantor-Taylor brush configuration case

    NASA Astrophysics Data System (ADS)

    Shavit, U.; Bar-Yosef, G.; Rosenzweig, R.; Assouline, S.

    2002-12-01

    The free flow problem above, at the surface interface, and inside a Cantor-Taylor brush configuration (CTB), simulating a porous medium, was studied. Particle image velocimetry (PIV) measurements confirm that the microscale Stokes equation provides an accurate solution to the CTB microscale flow problem. A comparison between the results of the averaged microscale Stokes equation and that of the Brinkman equation using an apparent viscosity shows that the concept of "apparent viscosity" did not provide a satisfactory agreement between the two approaches. In order to develop a description of the average velocity profile across the interface flow region, theoretical and numerical analyses were performed. An averaging procedure of the Navier Stokes equations provided a set of three equations, which were used to predict the average velocity in the fluid phase f. This set of equations is the suggested modified Brinkman equation (MBE). The comparison between the results of the Stokes equation and the MBE shows that optimizing the size of the averaging representative volume provides a good fit between the flow problem and the solution of the modified Brinkman equation.

  13. Aneurysm Formation After Endovascular Treatment of Acute Type A Dissection.

    PubMed

    Yang, Lai; Wang, Jiaping

    2016-08-01

    Recently, reports have described successful endovascular stent graft (ESG) treatment of patients with acute type A aortic dissection. We report 1 ESG treatment for this condition and the complication of a new aneurysm formation during a 6-month follow-up. PMID:27630269

  14. Endovascular Treatment of Traumatic Pseudoaneurysm Presenting as Intractable Epistaxis

    PubMed Central

    Zhang, Chang wei; You, Chao; Mao, Bo yong; Wang, Chao hua; He, Min; Sun, Hong

    2010-01-01

    Objective To investigate the clinical efficacy of individual endovascular management for the treatment of different traumatic pseudoaneurysms presenting as intractable epistaxis. Materials and Methods For 14 consecutive patients with traumatic pseudoaneurysm presenting as refractory epistaxes, 15 endovascular procedures were performed. Digital subtraction angiography revealed that the pseudoaneurysms originated from the internal maxillary artery in eight patients; and all were treated with occlusion of the feeding artery. In six cases, they originated from the internal carotid artery (ICA); out of which, two were managed with detachable balloons, two with covered stents, one by means of cavity embolization, and the remaining one with parent artery occlusion. All of these cases were followed up clinically from six to 18 months, with a mean follow up time of ten months; moreover, three cases were also followed with angiography. Results Complete cessation of bleeding was achieved in all the 15 instances (100%) immediately after the endovascular therapies. Of the six patients who suffered from ICA pseudoaneurysms, one presented with a permanent stroke and one had an episode of rebleeding requiring intervention. Conclusion In patients presenting with a history of craniocerebral trauma, traumatic pseudoaneurysm must be considered as a differential diagnosis. Individual endovascular treatment is a relatively safe, plausible, and reliable means of managing traumatic pseudoaneurysms. PMID:21076585

  15. Clinical Analysis of Giant Intracranial Aneurysms with Endovascular Embolization

    PubMed Central

    Ha, Sang Woo

    2012-01-01

    Objective The purpose of this study was to perform a clinical analysis of nine patients with giant aneurysms managed with endovascular embolization. Methods From March 2000 to September 2009, nine cases of giant intracranial aneurysms were treated (five unruptured and four ruptured). The nine patients included two males and seven females who were 47 to 72 years old (mean, 59.2 years old). The types of giant intracranial aneurysms were eight internal carotid artery aneurysms and one vertebral artery aneurysm. Treatment for each aneurysm was chosen based on anatomic relationships, aneurysmal factors, and the patients' clinical state. Three patients underwent endovascular coiling with stent and six initially underwent endovascular coiling alone. Medical records, operation records, postoperative angiographies, and follow-up angiographies were reviewed retrospectively. Results Eight out of nine patients showed good clinical outcomes. (six were excellent and two were good) after a mean follow-up period of 27.9 months. Six (67%) of the nine patients had a near-complete occlusions on the post-operative angiogram (mean, 13.5 months after the procedure). Occlusion rates of 90% or higher were obtained for eight (89%) of all the patients. One patient died due to multiple organ failure. Stents were ultimately required at some point for managing four aneurysms. Two patients needed additional procedures because of aneurysm regrowth. Conclusion Endovascular treatment could be an alternative option for managing giant aneurysms adjuvant to surgical intervention. PMID:23210026

  16. 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

  17. 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

  18. 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

  19. 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.

  20. 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

  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. 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.

  3. Aortic Wall Injury Related to Endovascular Therapy for Aortic Coarctation.

    PubMed

    Tretter, Justin T; Jones, Thomas K; McElhinney, Doff B

    2015-09-01

    Aortic wall complications can occur in unrepaired aortic coarctation (CoA) and after surgical repair or endovascular treatment. This review summarizes the available literature and current understanding of aortic wall injury (AWI) surrounding the management of CoA, focusing specifically on acute and follow-up AWI after endovascular treatment. There have been 23 reported cases of aortic rupture after endovascular treatment for CoA, including angioplasty alone, bare metal stenting, and primary covered stent therapy. Even if these published cases represent only a minority of ruptures that have actually occurred, the incidence is substantially <1%. The incidence of acute aneurysm formation was 0% to 13% after angioplasty, 0% to 5% after bare metal stent placement, and <1% after covered stent placement. The reported incidence and natural history of both acute and new AWI during follow-up after endovascular therapy for CoA varies considerably, likely secondary to ascertainment and reporting biases and inconsistent definitions. Although important AWI after endovascular treatment of CoA seems to be declining in frequency with increasing experience and improving technology, it remains one of the most important potential adverse outcomes. Long-term surveillance for new AWI and monitoring of existing AWI is mandatory, with institution of appropriate treatment when necessary. A central research focus in this population should be determination of the appropriate treatment for both native and recurrent CoA across various ages with regard to limiting recurrent CoA and preventing associated aortic wall complications, in addition to determining the appropriate treatment of various AWI. Consistent definitions and reporting are necessary to truly understand the incidence of, risk factors for, and measures protective against AWI after angioplasty or stent implantation for CoA.

  4. 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

  5. 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°.

  6. 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

  7. 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.

  8. Leaching study of PNL 76-68 glass beads using the LLNL continuous-flow method and the PNL-modified IAEA method. Final report

    SciTech Connect

    Buddemeier, R.W.; Coles, D.G.; Mensing, R.W.; Rego, J.; Weed, H.C.

    1982-08-20

    Lawrence Livermore National Laboratory (LLNL) has conducted a long-term single-pass continuous-flow (SPCF) leaching test of the glass waste form PNL 76-68. Leaching rates of Np, Pu, and various stable elements were measured at 25/sup 0/ and 75/sup 0/C with three different solutions and three different flow rates. The purposes of the study were: (1) to compare SPCF leaching results with the results of a modified IAEA leach test performed by Pacific Northwest Laboratories (PNL); (2) to establish elemental leach rates and their variation with temperature, flow rate and solution composition; and (3) to gain insight into the leaching mechanisms. The LLNL and PNL leach tests yielded results which appear to agree within experimental uncertainties. The magnitude of the leach rates determined for Np and the glass matrix elements is 10/sup -5/ grams of glass/cm/sup 2/ geometric solid surface area/day. The rates increase with temperature and with solution flow rate, and are similar in brine and distilled water but higher in a bicarbonate solution. Other cations exhibit somewhat different behavior, and Pu in particular yields a much lower apparent leach rate, probably because of sorption or precipitation effects after release from the glass matrix. After the initial few days, most elements are leached at a constant rate. Matrix dissolution appears to be the most probable rate controlling step for the leaching of most elements.

  9. Leaching study of PNL 76-68 glass beads using the LLNL continuous-flow method and the PNL modified IAEA method. Final report

    SciTech Connect

    Coles, D.G.; Mensing, R.W.; Rego, J.; Weed, H.C.; Buddemeier, R.W.

    1982-10-04

    A long-term single-pass continuous-flow (SPCF) leaching test was conducted on the glass waste form PNL 76-68. Leaching rates of Np, Pu and various stable elements were measured at 25 and 75/sup 0/C with three different solutions and three different flow rates. The SPCF leaching results were compared with results of a modified IAEA leach test performed by Pacific Northwest Laboratories (PNL). Elemental leach rates and their variation with temperature, flow rate and solution composition were established. The LLNL and PNL leach test results appear to agree within experimental uncertainties. The magnitude of the leach rates determined for Np and the glass matrix elements is 10/sup -5/ grams of glass/cm/sup 2/ geometric solid surface area/day. The rates increase with temperature and with solution flow rate, and are similar in brine and distilled water but higher in a bicarbonate solution. Other cations exhibit somewhat different behavior, and Pu in particular yields a much lower apparent leach rate, probably because of sorption or precipitation effects after release from the glass matrix. After the initial few days, most elements are leached at a constant rate. Matrix dissolution appears to be the most probable rate controlling step for the leaching of most elements. 23 figures, 12 tables.

  10. 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.

  11. Pathology specific secondary aortic interventions after thoracic endovascular aortic repair

    PubMed Central

    Scali, Salvatore T.; Beck, Adam W.; Butler, Khayree; Feezor, Robert J.; Martin, Tomas D.; Hess, Philip J.; Huber, Thomas S.; Chang, Catherine K.

    2014-01-01

    Objective: Despite improved short-term outcomes, concerns remain regarding durability of thoracic endovascular aortic repair(TEVAR). The purpose of this analysis was to evaluate the pathology-specific incidence of secondary aortic interventions(SAI) after TEVAR and their impact on survival. Methods: Retrospective review was performed of all TEVAR procedures and SAI at one institution from 2004-2011. Kaplan-Meier analysis was used to estimate survival. Results: Of 585 patients, 72(12%) required SAI at a median of 5.6 months(interquartile range(IQR):1.4-14.2) with 22(3.7%) requiring multiple SAI. SAI incidence differed significantly by pathology(P=.002): acute dissection(21.3%), post-surgical(20.0%), chronic dissection(16.7%), degenerative aneurysm(10.8%), traumatic transection(8.1%), penetrating ulcer(1.5%), and other etiologies(14.8%). Most common indications after dissection were persistent false lumen flow and proximal/distal extension of disease. For degenerative aneurysms, SAI was performed primarily to treat type I/III endoleaks. SAI patients had a greater mean number of comorbidities(P<.0005), stents placed(P=.0002), and postoperative complications after the index TEVAR(P<.0005) compared to those without SAI. Freedom from SAI at 1 and 5 years(95% CI) was estimated to be 86%(82-90%) and 68%(57-76%), respectively. There were no differences in survival(95% CI) between patients requiring SAI and those who did not: SAI 1-year: 88%(77-93%), 5-year: 51%(37-63%) and no SAI 1-year: 82%(79-85%), 5-year: 67%(62-71%)(Log-rank P=0.2). Conclusion: SAI after TEVAR is not uncommon, particularly in patients with dissection, but does not affect long-term survival. Aortic pathology is the most important variable impacting survival and dictated need, timing and mode of SAI. The varying incidence of SAI by indication underscores the need for diligent surveillance protocols that should be pathology-specific. PMID:24571937

  12. 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

  13. 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

  14. 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.

  15. Endovascular stenting for type B dissection involving a right-sided aortic arch

    PubMed Central

    Croccia, Maria Grazia; Levantino, Maurizio; Cioni, Roberto; Bortolotti, Uberto

    2012-01-01

    Endovascular stent-graft repair is emerging as the treatment of choice for complicated type B aortic dissection. In this report we describe a patient who presented with type B aortic dissection involving a right-sided aortic arch (RAA), a rare congenital vascular anomaly. The initial aggressive medical treatment proved unsuccessful due to false aneurysm expansion. Given the greater complexity of conventional surgical repair and the limited experience with this rare malformation, endovascular repair was preferred and successfully performed. We report the first case of endovascular repair of type B dissection involving RAA, confirming that endovascular treatment is technically feasible also when the dissection involves this unusual vascular malformation. PMID:22561295

  16. When do plants modify fluvial processes? Plant-hydraulic interactions under variable flow and sediment supply rates

    NASA Astrophysics Data System (ADS)

    Manners, Rebecca B.; Wilcox, Andrew C.; Kui, Li; Lightbody, Anne F.; Stella, John C.; Sklar, Leonard S.

    2015-02-01

    Flow and sediment regimes shape alluvial river channels; yet the influence of these abiotic drivers can be strongly mediated by biotic factors such as the size and density of riparian vegetation. We present results from an experiment designed to identify when plants control fluvial processes and to investigate the sensitivity of fluvial processes to changes in plant characteristics versus changes in flow rate or sediment supply. Live seedlings of two species with distinct morphologies, tamarisk (Tamarix spp.) and cottonwood (Populus fremontii), were placed in different configurations in a mobile sand-bed flume. We measured the hydraulic and sediment flux responses of the channel at different flow rates and sediment supply conditions representing equilibrium (sediment supply = transport rate) and deficit (sediment supply < transport rate). We found that the hydraulic and sediment flux responses during sediment equilibrium represented a balance between abiotic and biotic factors and was sensitive to increasing flow rates and plant species and configuration. Species-specific traits controlled the hydraulic response: compared to cottonwood, which has a more tree-like morphology, the shrubby morphology of tamarisk resulted in less pronation and greater reductions in near-bed velocities, Reynolds stress, and sediment flux rates. Under sediment-deficit conditions, on the other hand, abiotic factors dampened the effect of variations in plant characteristics on the hydraulic response. We identified scenarios for which the highest stem-density patch, independent of abiotic factors, dominated the fluvial response. These results provide insight into how and when plants influence fluvial processes in natural systems.

  17. 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

  18. Management of hemorrhagic high jugular bulb with adhesive otitis media in an only hearing ear: transcatheter endovascular embolization using detachable coils.

    PubMed

    Kondoh, Kazumasa; Kitahara, Tadashi; Mishiro, Yasuo; Okumura, Shin-ichi; Kubo, Takeshi

    2004-12-01

    A 51-year-old woman had a hemorrhagic high jugular bulb protruding into the posterosuperior part of the tympanic cavity in her left ear. This (only hearing) ear had severe adhesive otitis media resulting in repetitive hemorrhage from the jugular bulb. Therefore, treatment to stop the bleeding was required. Since invasive middle ear surgery in an only hearing ear would involve a high risk of hearing loss and massive bleeding, transcatheter endovascular embolization using detachable coils was selected for this special case; it safely blocked the blood flow and preserved the patient's hearing level. This is the first such report in the otosurgical field, showing that transcatheter endovascular embolization using detachable coils was quite effective in a difficult case of a hemorrhagic high jugular bulb with severe adhesive otitis media in an only hearing ear.

  19. 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

  20. 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

  1. 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.

  2. 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

  3. 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.

  4. Modelling stream flow and quantifying blue water using modified STREAM model in the Upper Pangani River Basin, Eastern Africa

    NASA Astrophysics Data System (ADS)

    Kiptala, J. K.; Mul, M. L.; Mohamed, Y.; van der Zaag, P.

    2013-12-01

    Effective management of all water uses in a river basin requires spatially distributed information of evaporative water use and the link towards the river flows. Physically based spatially distributed models are often used to generate this kind of information. These models require enormous amounts of data, if not sufficient would result in equifinality. In addition, hydrological models often focus on natural processes and fail to account for water usage. This study presents a spatially distributed hydrological model that has been developed for a heterogeneous, highly utilized and data scarce river basin in Eastern Africa. Using an innovative approach, remote sensing derived evapotranspiration and soil moisture variables for three years were incorporated as input data in the model conceptualization of the STREAM model (Spatial Tools for River basin Environmental Analysis and Management). To cater for the extensive irrigation water application, an additional blue water component was incorporated in the STREAM model to quantify irrigation water use (ETb(I)). To enhance model parameter identification and calibration, three hydrological landscapes (wetlands, hill-slope and snowmelt) were identified using field data. The model was calibrated against discharge data from five gauging stations and showed considerably good performance especially in the simulation of low flows where the Nash-Sutcliffe Efficiency of the natural logarithm (Eln) of discharge were greater than 0.6 in both calibration and validation periods. At the outlet, the Eln coefficient was even higher (0.90). During low flows, ETb(I) consumed nearly 50% of the river flow in the river basin. ETb(I) model result was comparable to the field based net irrigation estimates with less than 20% difference. These results show the great potential of developing spatially distributed models that can account for supplementary water use. Such information is important for water resources planning and management in heavily

  5. Endovascular repair of traumatic thoracic aortic injuries: a critical appraisal.

    PubMed

    Lin, Peter H; Huynh, Tam T; Kougias, Panagiotis; Wall, Mathew J; Coselli, Joseph S; Mattox, Kenneth L

    2008-08-01

    Blunt trauma to the thoracic aorta is life-threatening, with instant fatality in at least 75% of victims. If left untreated, nearly half of those who survive the initial injury will die within the first 24 hours. Surgical repair has been the standard treatment of blunt aortic injury, but immediate operative intervention is frequently difficult due to concomitant injuries. Although endovascular treatment of traumatic aortic disruption is less invasive than conventional repair via thoracotomy, this strategy remains controversial in young patients due to anatomical considerations and device limitations. This article reviews the likely advantages of endovascular interventions for blunt thoracic aortic injuries. Potential limitations and clinical outcomes of this minimally invasive technique are also discussed.

  6. [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

  7. 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.

  8. 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

  9. Chronic mesenteric ischemia: efficacy and outcome of endovascular therapy.

    PubMed

    Loffroy, Romaric; Guiu, Boris; Cercueil, Jean-Pierre; Krausé, Denis

    2010-06-01

    Chronic mesenteric ischemia is a rare condition caused by occlusive disease of the mesenteric vessels and manifested most commonly as abdominal pain. While the traditional therapy in symptomatic patients has been surgery, recent improvements in interventional devices and refinement in techniques have increased the popularity of endovascular treatment. The high procedural success and the low complication rate make the catheter-based approach an interesting alternative to surgery. Percutaneous angioplasty and stenting is now recognized as a minimally invasive means of obtaining good long-term results and is consequently suggested for the primary treatment of chronic mesenteric ischemia. This article presents a review of the literature on indications and technical aspects of endovascular treatment, with emphasis on short- and long-term outcomes.

  10. 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

  11. [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

  12. Three-dimensional CFD/MRI modeling reveals that ventricular surgical restoration improves ventricular function by modifying intraventricular blood flow.

    PubMed

    Khalafvand, S S; Zhong, L; Ng, E Y K

    2014-10-01

    Surgical ventricular restoration (SVR) is designed to normalize distorted ventricular shape and size in patients with left ventricular (LV) dysfunction and akinetic and dyskinetic segments. This study is aimed to quantify the characteristics of LV as a pump for a case before and after SVR, which is followed by coronary artery bypass grafting (CABG). We hypothesize that SVR+CABG improves heart flow. A patient with heart failure had magnetic resonance (MR) scans before and 4 months after SVR. LV endocardial geometries were semi-automated segmented and reconstructed using our customized algorithm. The arbitrary Lagrangian-Eulerian formulation of Navier-Stokes equations was solved to derive the flow patterns and calculate pressure differences in LV. After SVR, LV ejection fraction increased from 34% to 48% in patient but was still lower than normal (70%). Second, LV vortices were stronger than pre-surgery but still weaker than normal. The maximum pressure differences between ventricular base and apex increased from 180 to 400 Pa during diastole, from 252 to 560 Pa during systole, respectively. As anticipated, SVR reduced LV volumes and augmented LV ejection fraction. Three-dimensional CFD/MRI modeling suggests that improved diastolic and systolic ventricular function after SVR is associated with changes in intraventricular blood flow.

  13. 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.

  14. 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.

  15. 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.

  16. Endovascular treatment of unruptured posterior circulation intracranial aneurysms

    PubMed Central

    Lv, Xianli; Ge, Huijian; Jin, Hengwei; He, Hongwei; Jiang, Chuhan; Li, Youxiang

    2016-01-01

    Background and Purpose: Endovascular treatment of unruptured posterior circulation intracranial aneurysms (UPCIAs) is limited in the International Study of Unruptured Intracranial Aneurysms (ISUIA). The aim of this study is to evaluate the periprocedural morbidity, mortality, and midterm clinical and angiographic follow-ups of endovascular treatment of UPCIAs. Materials and Methods: Retrospective analysis of all patients treated in a 2-year period (89 patients: 10–78 years of age, mean: 45.5 ± 14.3/92 UPCIAs). Fifty-eight aneurysms were found incidentally, 12 in association with mass effect symptoms and 22 with stroke. Results: A clinical improvement or stable outcome was achieved in 84 patients (94.4%). The two cases of permanent morbidity included a patient with paralysis and another patient with hemianopia. One patient died after treatment of a giant fusiform vertebrobasilar aneurysm. In one patient, the aneurysm ruptured during treatment, resulting in death. Another patient suffered a fatal aneurysm rupture 4 days after treatment. Giant size (P = 0.005) and mass effect presentation (P = 0.029) were independent predictors of unfavorable outcomes in UPCIAs. Angiographic follow-up was available in 76 of the 86 surviving patients (88.4%) with a mean of 6.8 months (range: 1–36 months). Recanalization in six patients (7.9%) at 3 months, 4 months, 4 months, 24 months, and 36 months required retreatment in three patients. In-stent stenosis of >50% was found in three patients. Conclusion: Endovascular therapy is an attractive option for UPCIAs with stable midterm outcome. However, the current endovascular option seems to have a limitation for the treatment of the aneurysm with giant size or mass effect presentation. PMID:27570378

  17. Endovascular management of recurrent adult coarctation of the aorta.

    PubMed

    Kpodonu, Jacques; Ramaiah, Venkatesh G; Rodriguez-Lopez, Julio A; Diethrich, Edward B

    2010-11-01

    Traditional open surgical repair has proven to be an effective treatment for the management of primary and recurrent coarctation of the thoracic aorta. Potential complications at short-term and long-term follow-up have included recurrent coarctation, hypertension, premature coronary artery disease, cerebrovascular disease, and anastomotic pseudoaneurysm. Endovascular repair of recurrent coarctation of the thoracic aorta offers a less invasive treatment approach in potential high-risk surgical patients.

  18. 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.

  19. 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.

  20. Endovascular abdominal aortic aneurysm repair in the octogenarian.

    PubMed

    Brinkman, William T; Terramani, Thomas T; Najibi, Sasan; Weiss, Victor J; Salam, Atef A; Dodson, Thomas F; Smith, Robert B; Chaikof, Elliot L

    2004-07-01

    The aim of this study was to analyze patient outcomes following endovascular repair of infrarenal abdominal aortic aneurysms (EAR) among patients 80 years of age or older. In this study, reporting standards of the Ad Hoc Committee for Standardized Reporting Practices for Endovascular Aortic Aneurysm Repair of the Society of Vascular Surgery/American Association for Vascular Surgery (SVS/AAVS) were followed. Between August 8, 1996 and February 12, 2001 EAR was performed in 31 patients (29 male and 2 female) with an average age of 83 +/- 3 years and an average maximum aneurysm diameter of 59 +/- 7 mm. Overall technical success was 90% (28/31) with a single acute conversion and a 6% (2/32) incidence of major morbidity. There were no in-hospital deaths, but two patients (6%) died within 30 days of intervention. Four endoleaks, two type I and two type II, were observed within the first 30 days after endograft implantation and three new type II endoleaks were noted after implant periods that exceeded 1 month. Average follow-up was 16 months, with a single aneurysm-related death that occurred after late conversion to open repair, 2 years following initial endovascular treatment. Kaplan-Meier analysis revealed 3-, 12-, and 24-month estimated survivals of 93% (+/-5), 75% (+/-8), and 68% (+/-10), respectively. Clinical success rates were 90% (+/-5), 90% (+/-5), and 72% (+/-17) at 12, 24, and 36 months, respectively. We conclude that, in the octogenarian with mild to moderate medical comorbidities, endovascular aneurysm repair provides an alternative to open AAA repair with low operative morbidity and good clinical success rates. Elevated SVS/AAVS medical comorbidity scores were not associated with increased operative mortality rates, but they did show a trend toward decreased mid-term survival. Careful consideration of life expectancy and the probability of rupture, as with traditional AAA repair, should dictate necessity for intervention. PMID:15175935

  1. 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

  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. 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.

  4. 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.

  5. A Trial of Imaging Selection and Endovascular Treatment for Ischemic Stroke

    PubMed Central

    Kidwell, Chelsea S.; Jahan, Reza; Gornbein, Jeffrey; Alger, Jeffry R.; Nenov, Val; Ajani, Zahra; Feng, Lei; Meyer, Brett C.; Olson, Scott; Schwamm, Lee H.; Yoo, Albert J.; Marshall, Randolph S.; Meyers, Philip M.; Yavagal, Dileep R.; Wintermark, Max; Guzy, Judy; Starkman, Sidney; Saver, Jeffrey L.

    2013-01-01

    BACKGROUND Whether brain imaging can identify patients who are most likely to benefit from therapies for acute ischemic stroke and whether endovascular thrombectomy improves clinical outcomes in such patients remains unclear. METHODS In this study, we randomly assigned patients within 8 hours after the onset of large-vessel, anterior-circulation strokes to undergo mechanical embolectomy (Merci Retriever or Penumbra System) or receive standard care. All patients underwent pretreatment computed tomography or magnetic resonance imaging of the brain. Randomization was stratified according to whether the patient had a favorable penumbral pattern (substantial salvageable tissue and small infarct core) or a non-penumbral pattern (large core or small or absent penumbra). We assessed outcomes using the 90-day modified Rankin scale, ranging from 0 (no symptoms) to 6 (dead). RESULTS Among 118 eligible patients, the mean age was 65.5 years, the mean time to enrollment was 5.5 hours, and 58% had a favorable penumbral pattern. Revascularization in the embolectomy group was achieved in 67% of the patients. Ninety-day mortality was 21%, and the rate of symptomatic intracranial hemorrhage was 4%; neither rate differed across groups. Among all patients, mean scores on the modified Rankin scale did not differ between embolectomy and standard care (3.9 vs. 3.9, P = 0.99). Embolectomy was not superior to standard care in patients with either a favorable penumbral pattern (mean score, 3.9 vs. 3.4; P = 0.23) or a nonpenumbral pattern (mean score, 4.0 vs. 4.4; P = 0.32). In the primary analysis of scores on the 90-day modified Rankin scale, there was no interaction between the pretreatment imaging pattern and treatment assignment (P = 0.14). CONCLUSIONS A favorable penumbral pattern on neuroimaging did not identify patients who would differentially benefit from endovascular therapy for acute ischemic stroke, nor was embolectomy shown to be superior to standard care. (Funded by the

  6. A modified Shkadov's model for thin film flow of a power law fluid over an inclined surface

    NASA Astrophysics Data System (ADS)

    Amaouche, Mustapha; Djema, Amar; Bourdache, L.

    2009-01-01

    A new evolution equation coherent up to order one in the long wave parameter is derived to describe the non-linear behavior of a thin film flow down an inclined plane of a power law fluid for small to moderate Reynolds numbers. The method we have used combines the lubrication theory and the weighted residual approach, with a suitable weighting function. That approach was first developed by Ruyer-Quil and Manneville (2000) for Newtonian fluids. The model has the advantages of both the Shkadov type approach far from criticality and that of Benney close to criticality. To cite this article: M. Amaouche et al., C. R. Mecanique 337 (2009).

  7. 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.

  8. Improving the Evaluation of Collateral Circulation by Multiphase Computed Tomography Angiography in Acute Stroke Patients Treated with Endovascular Reperfusion Therapies

    PubMed Central

    García-Tornel, Alvaro; Carvalho, Vanessa; Boned, Sandra; Flores, Alan; Rodríguez-Luna, David; Pagola, Jorge; Muchada, Marian; Sanjuan, Estela; Coscojuela, Pilar; Juega, Jesus; Rodriguez-Villatoro, Noelia; Menon, Bijoy; Goyal, Mayank; Ribó, Marc; Tomasello, Alejandro; Molina, Carlos A.; Rubiera, Marta

    2016-01-01

    Good collateral circulation (CC) is associated with favorable outcomes in acute stroke, but the best technique to evaluate collaterals is controversial. Single-phase computed tomography angiography (sCTA) is widely used but lacks temporal resolution. We aim to compare CC evaluation by sCTA and multiphase CTA (mCTA) as predictors of outcome in endovascular treated patients. Methods Consecutive endovascular treated patients with M1 middle cerebral artery (MCA) or terminal intracranial carotid artery (TICA) occlusion confirmed by sCTA were included. Two more CTA acquisitions with 8- and 16-second delays were performed for mCTA. Endovascular thrombectomy was performed independently of the CC status according to a local protocol [Alberta Stroke Program Early CT score (ASPECTS) >6, modified Rankin scale (mRS) score <3]. CC on sCTA and mCTA were compared. Results 108 patients were included. Their mean age was 69.6 ± 13 years and their median National Institutes of Health Stroke Scale (NIHSS) score was 17 (interquartile range 8). 79 (73.1%) had M1 MCA and 29 (26.9%) TICA occlusions. The mean time from symptom onset to CTA was 146.8 ± 96.5 min. On sCTA, 50.9% patients presented good CC vs. 57.5% on mCTA. Good CC status in both sCTA and mCTA had a lower 24-hour infarct volume (27.4 vs. 74.8 cm3 on sCTA, p = 0.04; 17.2 vs. 97.8 cm3 on mCTA, p < 0.01). However, only good CC on mCTA was associated with lower 24-hour (5 vs. 8.5, p = 0.04) and median discharge NIHSS (2 vs. 4.5, p = 0.04) scores and functional independency (mRS score <3) at 3 months (76.9 vs. 23.1%, p < 0.01). In a logistic regression model including age, NIHSS, ASPECTS and recanalization, only age (OR 0.96, 95% CI 0.93–0.99, p = 0.02) and good CC on mCTA (OR 5, 95% CI 1.99-12.6, p < 0.01) were independent predictors of functional outcome at 3 months. Conclusion CC evaluation by mCTA is a better prognostic marker than CC evaluation by sCTA for clinical and functional endpoints in acute stroke patients treated

  9. Functional Independence following Endovascular Treatment for Basilar Artery Occlusion despite Extensive Bilateral Pontine Infarcts on Diffusion-Weighted Imaging: Refuting a Self-Fulfilling Prophecy

    PubMed Central

    Haussen, Diogo C.; Oliveira, Renato A.C.; Patel, Vikas; Nogueira, Raul G.

    2016-01-01

    Background and Purpose Extensive brainstem diffusion-weighted imaging (DWI) hyperintensity has been associated with poor outcomes. We aim at documenting a series of patients with extensive DWI pontine lesions who achieved independence following endovascular therapy and aggressive medical therapy in the setting of posterior circulation basilar artery occlusion (BAO). Methods This is a retrospective endovascular database review of a single-operator experience over a 9-year period for patients with (1) complete BAO, (2) extensive bilateral pontine DWI changes and (3) 90-day modified Rankin scale 0–2. Results Three out of a total of 40 patients met the inclusion criteria. Case 1 was an 18-year-old male with National Institutes of Health Stroke Scale (NIHSS) 32 on admission, treated 25 h after symptom onset. Case 2 was a 56-year-old male with NIHSS 19, treated 10 h after onset. Case 3 was a 73-year-old male with NIHSS 29, treated 6 h after onset. Full endovascular reperfusion was achieved in all 3 patients. A literature review identified 9 additional cases of extensive pontine DWI changes and good outcome. These patients were young (32 ± 22 years), mostly males (69%), presented with a relatively low posterior circulation Acute Stroke Prognosis Early CT Score (6 ± 1), were treated relatively late from last known normal (13 ± 10 h) and were mostly (84%) treated with endovascular intervention. Conclusion Extensive bilateral pontine DWI lesions among patients with BAO are not an unequivocal indicator of poor prognosis. We advise strong caution when considering these findings in the treatment decision algorithm. PMID:27781047

  10. 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.

  11. Endovascular Device Testing with Particle Image Velocimetry Enhances Undergraduate Biomedical Engineering Education

    ERIC Educational Resources Information Center

    Nair, Priya; Ankeny, Casey J.; Ryan, Justin; Okcay, Murat; Frakes, David H.

    2016-01-01

    We investigated the use of a new system, HemoFlow™, which utilizes state of the art technologies such as particle image velocimetry to test endovascular devices as part of an undergraduate biomedical engineering curriculum. Students deployed an endovascular stent into an anatomical model of a cerebral aneurysm and measured intra-aneurysmal flow…

  12. Endovascular Treatment of Vertebral Artery Injury during Cervical Posterior Fusion (C1 Lateral Mass Screw)

    PubMed Central

    Yoon, Kyeong-Wook; Ko, Jung-Ho; Cho, Chun-Sung; Lee, Sang-Koo; Kim, Young-Joon; Kim, Young Jin

    2013-01-01

    Summary We describe two cases of vertebral artery injury during posterior cervical fusion. We treated both cases by an endovascular technique. The vertebral artery injury may result in catastrophic situations, such as, infarction, massive blood loss and even death. Our clinical outcome was good and we prove that endovascular treatment is an effective and less invasive way to treat vertebral artery injury. PMID:24070088

  13. 77 FR 8117 - Medical Devices; Cardiovascular Devices; Classification of the Endovascular Suturing System

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-14

    ... HUMAN SERVICES Food and Drug Administration 21 CFR Part 870 Medical Devices; Cardiovascular Devices; Classification of the Endovascular Suturing System AGENCY: Food and Drug Administration, HHS. ACTION: Final rule. SUMMARY: The Food and Drug Administration (FDA) is classifying the endovascular suturing system into...

  14. 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.

  15. 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

  16. 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).

  17. [Clinical application of reticulated platelet analysis using the matic-modified thiazole orange method and flow cytometry].

    PubMed

    Toba, K; Fuse, I; Koike, T; Tsuchiyama, J; Higuchi, W; Niikuni, K; Abe, T; Yano, T; Takahashi, M; Shibata, A; Aizawa, Y

    2000-11-01

    Reticulated platelet (RP) analysis using thiazole orange (TO) and a flow cytometer is a convenient and promising method for estimating platelet kinetics in patients with thrombocytopenia. Among many different modifications of the TO method, a novel protocol reported by Matic in 1998 seems to be superior because it allows RP analysis using a sample of whole blood very quickly and accurately. Therefore, we used this method to analyze platelet kinetics in patients with idiopathic thrombocytopenic purpura (ITP) and hemophagocytic syndrome (HPS), as well as patients with hematopoietic malignancies (HM) after intensive chemotherapy. The proportion of RP was increased in the patients with ITP and HPS, and furthermore showed a negative linear correlation with the platelet count. The change in the proportion of RP occurred about one week before the change in the circulating platelet count in the patients with HM after chemotherapy. This modification of the TO method by Matic is expected to become a standard protocol for RP analysis.

  18. 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

  19. 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.

  20. 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.

  1. 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

  2. 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

  3. 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.

  4. 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

  5. Electromagnetic treatment to old Alzheimer's mice reverses β-amyloid deposition, modifies cerebral blood flow, and provides selected cognitive benefit.

    PubMed

    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 treatment

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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

  14. 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

  15. Endovascular exclusion of aortoesophageal fistula after coarctation extraanatomical bypass.

    PubMed

    Myers, Patrick O; Gemayel, Gino; Mugnai, Damiano; Murith, Nicolas; Kalangos, Afksendiyos

    2014-07-01

    Extraanatomical bypass has been advocated as the primary technique in adolescents or adults presenting with aortic coarctation. This approach carries significant morbidity, and graft-related complications may be more important in the young patient population. A 52-year-old man who had previously undergone extraanatomical bypass of aortic coarctation was diagnosed with a distal anastomotic pseudoaneurysm and aortoesophageal fistula. This was managed by proximal bypass plugging with an occluder, endovascular exclusion with a stent-graft in the thoracic descending aorta covering the pseudoaneurysm, and coarctation balloon dilation. Aortoesophageal fistula is a late complication observed after extraanatomical bypass for coarctation. This case illustrates this rare complication.

  16. Endovascular treatment for acute pulmonary embolism in neurological patient.

    PubMed

    Paul, Gunchan; Paul, Birinder S; Gautam, Parshotam L; Mohan, Bishav; Sharma, Shruti

    2015-07-01

    Among the spectrum of venous thrombo-embolic disease, acute pulmonary embolism accounts for the most life threatening manifestations with mortality exceeding 50%. It can affect many patient populations across various disciplines, hence immediate attention and aggressive treatment is crucial. With the advancement of technologies, various catheter-based devices are available to treat massive or submassive PE. In this paper we report two patients of acute pulmonary embolism with neurological issues where the life threatening emergency was successfully managed by utilizing endovascular directed thrombolytic reperfusion therapy. PMID:26609298

  17. 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

  18. Patient effective dose from endovascular brachytherapy with 192Ir sources.

    PubMed

    Perma, L; Bianchi, C; Nicolini, G; Novario, R; Tanzi, F; Conte, L

    2002-01-01

    The growing use of endovascular brachytherapy has been accompanied by the publication of a large number of studies in several fields, but few studies on patient dose have been found in the literature. Moreover, these studies were carried out on the basis of Monte Carlo simulation. The aim of the present study was to estimate the effective dose to the patient undergoing endovascular brachytherapy treatment with 112Ir sources, by means of experimental measurements. Two standard treatments were taken into account: an endovascular brachytherapy of the coronary artery corresponding to the activity x time product of 184 GBq.min and an endovascular brachytherapy of the renal artery (898 GBq.min). Experimental assessment was accomplished by thermoluminescence dosemeters positioned in more than 300 measurement points in a properly adapted Rqndo phantom. A method has been developed to estimate the mean organ doses for all tissues and organs concerned in order to calculate the effective dose associated with intravascular brachytherapy. The normalised organ doses resulting from cronary treatment were 2.4 x 10(-2) mSv.GBq(-1).min(-1) for lung, 0.9 x 10(-2) mSv.GBSq(-1).min(-1) for oesophagus and 0.48 x 10(-2) mS.GBq(-1).min(-1) for bone marrow. During brachytherapy of the renal artery, the corresponding normalised doses were 4.2 x 10(-2) mS.GBq(-1).min(-1) for colon, 7.8 x 10(-2) mSv.GBq(-1).min(-1) for stomach and 1.7 x 10(-2) mSv.GBq(-1).min(-1) for liver. Coronary treatment iJnvlled an efl'fective dose of (0.046 mSv.GBq(-1).min(-1), whereas the treatment of the renal artery resulted in an effective dose of 0.15 mSv.GBq(-1).min(-1); there were many similarities with data from former studies. Based on these results it can be concluded that the dose level of patients exposed during brachytherapy treatment is low.

  19. Impact of the volume of aneurysmal contents on intraaneurysmal pressure after endovascular grafting (experimental studies).

    PubMed

    Volodos', S N; Sayers, R D; Bell, P R F; Gostelow, J P

    2005-01-01

    With the purpose of clarifying the nature and outlining certain constituents of such an undesirable condition designated as "endotension", that emerges after transluminal grafting of the aneurysmally changed aorta, a basic theoretical model was worked out for explanation of "endotension". Also, there was designed and constructed in vitro an original experimental model using which the authors carried out a study into the relationship between the pressure in the aneurysm after its complete exclusion from the blood flow by an endovascular graft and the volume of the aneurysmal contents. Some factors described in the literature as influencing the pressure level in the aneurysm were at the given stage purposefully excluded. The volume of the "aneurysm" reproduced in our model was equal to 675 ml; each of five vascular grafts implanted into the aneurysm measured 110 mm in length. The pulsating liquid flow was reproduced in the system using a serial appliance for extracorporeal circulation. The liquid was aspirated from the aneurysm by means of a syringe with concurrent pressure guidance in the sac. To start pressure lowering, it was necessary to evacuate 0.4-1.6 ml of the liquid. The real clinical situations were considered from the standpoint of our results.

  20. 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

  1. 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

  2. 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

  3. Endovascular Treatment of Type Ib Endoleak after Evar Using the IBD Device: A Case Report

    PubMed Central

    Vourliotakis, Georgios; Pikis, Stylianos; Tzilalis, Vasileios D.

    2016-01-01

    In the modern endovascular era, abdominal aortic aneurysm repair is still not free of complications with re-interventions following endovascular aneurysm repair (EVAR) being more common than with open surgical repair. A variety of endovascular, open surgical and combined techniques were described according to the anatomical considerations and general health of the patient to achieve the best possible result after these complications. In cases of type Ib endoleak following aorto-uni-lateral EVAR for an abdominal aortic aneurysm, the use of the internal branched device (IBD) constitutes a safe and effective technique.

  4. 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.

  5. 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.

  6. The use of endovascular stents in the treatment of penetrating ulcers of the thoracic aorta.

    PubMed

    Brittenden, J; McBride, K; McInnes, G; Gillespie, I N; Bradbury, A W

    1999-11-01

    Penetrating atheromatous ulcers of the aorta are increasingly recognized as a distinct entity. Although their natural history remains ill-defined, such ulcers may lead to pseudoaneurysmal formation, dissection, rupture, or embolization. Given the morbidity associated with open repair, endovascular repair of penetrating atheromatous ulcers may be the treatment of choice. Although stent-graft replacement of acute aortic dissections has recently been described, endovascular repair of penetrating thoracic aortic ulcers has not previously been reported. We report two cases of successful endovascular repair of penetrating atheromatous ulcers that previously ruptured.

  7. Radiological Changes in Infantile Dissecting Anterior Communicating Artery Aneurysm Treated Endovascularly

    PubMed Central

    Yatomi, Kenji; Oishi, Hidenori; Yamamoto, Munetaka; Suga, Yasuo; Nonaka, Senshu; Yoshida, Kensaku; Arai, Hajime

    2014-01-01

    Summary Intracranial aneurysms are extremely rare in infants, and to our knowledge only seven infants treated for ruptured spontaneous dissecting aneurysms have been reported. Good outcomes have been achieved with endovascular treatment of infantile aneurysm. We the endovascular treatment of a one-month-old girl for ruptured dissecting aneurysm located in the anterior communicating artery, and the unique radiological changes that were observed during the perioperative and follow-up periods. These changes suggest that blood coagulation and fibrinolytic response play a part in the repair and healing processes of dissecting aneurysms. Careful neuroradiological surveys are needed for pediatric dissecting aneurysms treated endovascularly. PMID:25496693

  8. 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.

  9. 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

  10. Endovascular angioplasty before resection of a sphenoidal meningioma with vascular encasement.

    PubMed

    Chivoret, N; Fontaine, D; Lachaud, S; Chau, Y; Sedat, J

    2011-09-01

    We describe a case of sphenoid wing meningioma presenting with cerebral infarction due to extended vascular encasement in which endovascular angioplasty was performed before surgery to avoid perioperative ischemia. A severe stenosis involved the intracranial internal carotid artery and the proximal segments of the middle and anterior cerebral arteries. Endovascular dilatation was followed by complete surgical resection. Preoperative mild aphasia and hemiparesia resolved completely after surgery. Endovascular angioplasty of arterial trunks and their branches can be proposed before the resection of skull base meningiomas encasing these arteries to decrease the risk of perioperative brain ischemia related to their surgical manipulation or vasospasm. PMID:22005706

  11. Repair of an acute blunt popliteal artery trauma via endovascular approach.

    PubMed

    Macedo, Francisco Igor B; Sciarretta, Jason D; Salsamendi, Jason; Karmacharya, Jagajan; Romano, Andrea; Namias, Nicholas

    2015-02-01

    Popliteal vascular trauma remains a challenging entity and carries the greatest risk of limb loss among the lower extremity vascular injuries. Operative management of patients presenting with traumatic popliteal vascular injuries continues to evolve. We present a case of successful endovascular repair with stent grafting of an acute blunt popliteal artery injury. Endovascular repair of traumatic popliteal vascular injuries appears as an attractive alternative to surgical repair in a very selective group of patients. Further investigation is still needed to define the safety and feasibility of endovascular approach in the management of traumatic popliteal vascular injuries.

  12. Endovascular angioplasty before resection of a sphenoidal meningioma with vascular encasement.

    PubMed

    Chivoret, N; Fontaine, D; Lachaud, S; Chau, Y; Sedat, J

    2011-09-01

    We describe a case of sphenoid wing meningioma presenting with cerebral infarction due to extended vascular encasement in which endovascular angioplasty was performed before surgery to avoid perioperative ischemia. A severe stenosis involved the intracranial internal carotid artery and the proximal segments of the middle and anterior cerebral arteries. Endovascular dilatation was followed by complete surgical resection. Preoperative mild aphasia and hemiparesia resolved completely after surgery. Endovascular angioplasty of arterial trunks and their branches can be proposed before the resection of skull base meningiomas encasing these arteries to decrease the risk of perioperative brain ischemia related to their surgical manipulation or vasospasm.

  13. Endovascular Angioplasty before Resection of a Sphenoidal Meningioma with Vascular Encasement

    PubMed Central

    Chivoret, N.; Fontaine, D.; Lachaud, S.; Chau, Y.; Sedat, J.

    2011-01-01

    Summary We describe a case of sphenoid wing meningioma presenting with cerebral infarction due to extended vascular encasement in which endovascular angioplasty was performed before surgery to avoid perioperative ischemia. A severe stenosis involved the intracranial internal carotid artery and the proximal segments of the middle and anterior cerebral arteries. Endovascular dilatation was followed by complete surgical resection. Preoperative mild aphasia and hemiparesia resolved completely after surgery. Endovascular angioplasty of arterial trunks and their branches can be proposed before the resection of skull base meningiomas encasing these arteries to decrease the risk of perioperative brain ischemia related to their surgical manipulation or vasospasm. PMID:22005706

  14. Bare, Bio-Active and Hydrogel-Coated Coils for Endovascular Treatment of Experimentally Induced Aneurysms

    PubMed Central

    Reinges, M.H.T.; Krings, T.; Drexler, A.Y.; Ludolph, A.; Sellhaus, B.; Bovi, M.; Geibprasert, S.; Agid, R.; Scherer, K.; Hans, F.J.

    2010-01-01

    Summary Endovascular treatments of cerebral aneurysms with bare platinum coils have a higher rate of recurrence compared to surgical clipping. This may be related to failed vessel wall reconstruction since histological and scanning electron microscopy results following embolization failed to demonstrate neoendothelialization over the aneurysm neck. The present study tried to elucidate whether the use of modified coils resulted in a better rate of reconstructing the vessel wall over the aneurysm neck in experimental aneurysms. Aneurysms were created in 20 rabbits by intraluminal elastase incubation of the common carotid artery. Five animals each were assigned to the following groups: untreated, bare platinum coils, bioactive coils with polyglycolic/polylactic acid coating, and hydrogel-coated platinum coils. After 12 months, angiography, histology and scanning electron microscopy was performed. No neoendothelial layer was visualized in the bioactive and bare coil groups with a tendency to an increased layering of fibroblasts along the bioactive coils at the aneurysm fundus. However, at the aneurysm neck perfused clefts were present and although a thin fibrinous layer was present over some coils, no bridging neointimal or neoendothial layer was noted over different coils. Following loose Hydrogel coiling, a complete obliteration of the aneurysm was present with neoendothelialization present over different coil loops. The study demonstrates that with surface coil modifications complete and stable aneurysm obliteration may become possible. A smooth and dense surface over the aneurysm neck may be necessary for endothelial cells to bridge the aneurysm neck and to lead to vessel wall reconstruction. PMID:20642888

  15. [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

  16. 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.

  17. Augmented reality system for freehand guide of magnetic endovascular devices.

    PubMed

    Parrini, S; Cutolo, F; Freschi, C; Ferrari, M; Ferrari, V

    2014-01-01

    Magnetic guide of endovascular devices or magnetized therapeutic microparticles to the specific target in the arterial tree is increasingly studied, since it could improve treatment efficacy and reduce side effects. Most proposed systems use external permanent magnets attached to robotic manipulators or magnetic resonance imaging (MRI) systems to guide internal carriers to the region of treatment. We aim to simplify this type of procedures, avoiding or reducing the need of robotic arms and MRI systems in the surgical scenario. On account of this we investigated the use of a wearable stereoscopic video see-through augmented reality system to show the hidden vessel to the surgeon; in this way, the surgeon is able to freely move the external magnet, following the showed path, to lead the endovascular magnetic device towards the desired position. In this preliminary study, we investigated the feasibility of such an approach trying to guide a magnetic capsule inside a vascular mannequin. The high rate of success and the positive evaluation provided by the operators represent a good starting point for further developments of the system. PMID:25570003

  18. Emergent Endovascular Stent Grafts for Ruptured Aortic Aneurysms

    PubMed Central

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

    2015-01-01

    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

  19. Endovascular solutions to arterial injury due to posterior spine surgery.

    PubMed

    Loh, Shang A; Maldonaldo, Thomas S; Rockman, Caron B; Lamparello, Patrick J; Adelman, Mark A; Kalhorn, Stephen P; Frempong-Boadu, Anthony; Veith, Frank J; Cayne, Neal S

    2012-05-01

    Iatrogenic arterial injury is an uncommon but recognized complication of posterior spinal surgery. The spectrum of injuries includes vessel perforation leading to hemorrhage, delayed pseudoaneurysm formation, and threatened perforation by screw impingement on arterial vessels. Repair of these injuries traditionally involved open direct vessel repair or graft placement, which can be associated with significant morbidity. We identified five patients with iatrogenic arterial injury during or after posterior spinal surgery between July 2004 and August 2009 and describe their endovascular treatment. Intraoperative arterial bleeding was encountered in two patients during posterior spinal surgery. The posterior wounds were packed, temporarily closed, and the patient was placed supine. In both patients, angiography demonstrated arterial injury necessitating repair. Covered stent grafts were deployed through femoral cutdowns to exclude the areas of injury. In three additional patients, postoperative computed tomography imaging demonstrated pedicle screws abutting/penetrating the thoracic or abdominal aorta. Angiography or intravascular ultrasound imaging, or both, confirmed indention/perforation of the aorta by the screw. Aortic stent graft cuffs were deployed through femoral cutdowns to cover the area of aortic contact before hardware removal. All five patients did well and were discharged home in good condition. Endovascular repair of arterial injuries occurring during posterior spinal procedures is feasible and can offer a safe and less invasive alternative to open repair.

  20. 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.

  1. 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

  2. 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

  3. Endovascular Versus Open Abdominal Aortic Aneurysm: Best Decision.

    PubMed

    Déglise, Sébastien; Delay, Charline; Saucy, François; Lejay, Anne; Dubuis, Céline; Briner, Lukas; Chakfé, Nabil; Corpataux, Jean-Marc

    2015-01-01

    Since the first implantation of an endograft in 1991, endovascular aneurysm repair (EVAR) rapidly gained recognition. Historical trials showed lower early mortality rates but these results were not maintained beyond 4 years. Despite newer-generation devices, higher rates of reintervention are associated with EVAR during follow-up. Therefore, the best therapeutic decision relies on many parameters that the physician has to take in consideration. Patient's preferences and characteristics are important, especially age and life expectancy besides health status. Aneurysmal anatomical conditions remain probably the most predictive factor that should be carefully evaluated to offer the best treatment. Unfavorable anatomy has been observed to be associated with more complications especially endoleak, leading to more re-interventions and higher risk of late mortality. Nevertheless, technological advances have made surgeons move forward beyond the set barriers. Thus, more endografts are implanted outside the instructions for use despite excellent results after open repair especially in low-risk patients. When debating about AAA repair, some other crucial points should be analysed. It has been shown that strict surveillance is mandatory after EVAR to offer durable results and prevent late rupture. Such program is associated with additional costs and with increased risk of radiation. Moreover, a risk of loss of renal function exists when repetitive imaging and secondary procedures are required. The aim of this article is to review the data associated with abdominal aortic aneurysm and its treatment in order to establish selection criteria to decide between open or endovascular repair. PMID:26333665

  4. 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.

  5. 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

  6. Endovascular Management of Vascular Injury during Transsphenoidal Surgery.

    PubMed

    Cinar, C; Bozkaya, H; Parildar, M; Oran, I

    2013-03-01

    Vascular injury is an unusual and serious complication of transsphenoidal surgery. We aimed to define the role of angiography and endovascular treatment in patients with vascular injuries occurring during transsphenoidal surgery. During the last ten-year period, we retrospectively evaluated nine patients with vascular injury after transsphenoidal surgery. Eight patients were symptomatic due to vascular injury, while one had only suspicion of vascular injury during surgery. Four patients presented with epistaxis, two with subarachnoid hemorrhage, one with exophthalmos, and one with hemiparesia. Emergency angiography revealed a pseudoaneurysm in four patients, contrast extravasation in two, vessel dissection in one, vessel wall irregularity in one, and arteriovenous fistula in one. All patients but one were treated successfully with parent artery occlusion, with one covered stent implantation, one stent-assisted coiling method, while one patient was managed conservatively. One patient died due to complications related to the primary insult without rebleeding. Vascular injuries suspected intra or postoperatively must be investigated rapidly after transsphenoidal surgery. Endovascular treatment with parent artery occlusion is feasible with acceptable morbidity and mortality rates in the treatment of vascular injuries occurring in transsphenoidal surgery. PMID:23472732

  7. Enhanced segmentation and skeletonization for endovascular surgical planning

    NASA Astrophysics Data System (ADS)

    Cheng, Irene; Firouzmanesh, Amirhossein; Leleve, Arnaud; Shen, Rui; Moreau, Richard; Brizzi, Vicenzo; Pham, Minh-Tu; Redarce, Tanneguy; Lermusiaux, Patrick; Basu, Anup

    2012-02-01

    Endovascular surgery is becoming widely deployed for many critical procedures, replacing invasive medical operations with long recovery times. However, there are still many challenges in improving the efficiency and safety of its usage, and reducing surgery time; namely, regular exposure to radiation, manual navigation of surgical tools, lack of 3D visualization, and lack of intelligent planning and automatic tracking of a surgical end-effector. Thus, our goal is to develop hardware and software components of a tele-operation system to alleviate the abovementioned problems. There are three specific objectives in this project: (i) to reduce the need for a surgeon to be physically next to a patient during endovascular surgery; (ii) to overcome the difficulties encountered in manual navigation; and, (iii) to improve the speed and experience of performing such surgeries. To achieve (i) we will develop an electro-mechanical interface to accurately guide mechanically controlled surgical tools from a close distance, along with a 3D visualization interface; for (ii) we will replace the current surgical tools with an "intelligent wire" controlled by the electro-mechanical system; for (iii) we will segment 3D medical images to extract precise shapes of blood vessels, following which we will perform automatic path planning for a surgical end-effector.

  8. Endovascular Management of Vascular Injury during Transsphenoidal Surgery.

    PubMed

    Cinar, C; Bozkaya, H; Parildar, M; Oran, I

    2013-03-01

    Vascular injury is an unusual and serious complication of transsphenoidal surgery. We aimed to define the role of angiography and endovascular treatment in patients with vascular injuries occurring during transsphenoidal surgery. During the last ten-year period, we retrospectively evaluated nine patients with vascular injury after transsphenoidal surgery. Eight patients were symptomatic due to vascular injury, while one had only suspicion of vascular injury during surgery. Four patients presented with epistaxis, two with subarachnoid hemorrhage, one with exophthalmos, and one with hemiparesia. Emergency angiography revealed a pseudoaneurysm in four patients, contrast extravasation in two, vessel dissection in one, vessel wall irregularity in one, and arteriovenous fistula in one. All patients but one were treated successfully with parent artery occlusion, with one covered stent implantation, one stent-assisted coiling method, while one patient was managed conservatively. One patient died due to complications related to the primary insult without rebleeding. Vascular injuries suspected intra or postoperatively must be investigated rapidly after transsphenoidal surgery. Endovascular treatment with parent artery occlusion is feasible with acceptable morbidity and mortality rates in the treatment of vascular injuries occurring in transsphenoidal surgery.

  9. Endovascular Management of Vascular Injury during Transsphenoidal Surgery

    PubMed Central

    Çinar, C.; Bozkaya, H.; Parildar, M.; Oran, I.

    2013-01-01

    Summary Vascular injury is an unusual and serious complication of transsphenoidal surgery. We aimed to define the role of angiography and endovascular treatment in patients with vascular injuries occurring during transsphenoidal surgery. During the last ten-year period, we retrospectively evaluated nine patients with vascular injury after transsphenoidal surgery. Eight patients were symptomatic due to vascular injury, while one had only suspicion of vascular injury during surgery. Four patients presented with epistaxis, two with subarachnoid hemorrhage, one with exophthalmos, and one with hemiparesia. Emergency angiography revealed a pseudoaneurysm in four patients, contrast extravasation in two, vessel dissection in one, vessel wall irregularity in one, and arteriovenous fistula in one. All patients but one were treated successfully with parent artery occlusion, with one covered stent implantation, one stent-assisted coiling method, while one patient was managed conservatively. One patient died due to complications related to the primary insult without rebleeding. Vascular injuries suspected intra or postoperatively must be investigated rapidly after transsphenoidal surgery. Endovascular treatment with parent artery occlusion is feasible with acceptable morbidity and mortality rates in the treatment of vascular injuries occurring in transsphenoidal surgery. PMID:23472732

  10. 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

  11. 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

  12. A flow cytometry-based immuno-titration assay for rapid and accurate titer determination of modified vaccinia Ankara virus vectors.

    PubMed

    Li, Zengji; Ling, Loni; Liu, Xiaohui; Laus, Reiner; Delcayre, Alain

    2010-10-01

    A flow cytometry-based immuno-titration titer assay was established to determine infectious unit (IU) and transducing unit (TU) of modified vaccinia Ankara (MVA) virus vectors. This titration method enumerates infected cells by measuring the expression of viral protein for IU and transgene protein for TU in individual cells after staining with fluorophore-conjugated antibodies. It presents many advantages over standard virus titration approaches, such as TCID(50) or plaque assay, for its convenience, rapidity and accuracy as illustrated by excellent assay linearity and reproducibility. Importantly, the IU and the TCID(50) assays generated similar batch-specific titer values when testing varied MVA-derived virus preparations. Assay development revealed that the post-infection time at which viral protein expression is evaluated, host cell type, and blocking the formation and release of progeny virion with nocodazole, an anti-microtubule agent or rifampin, a specific vaccinia virus assembly inhibitor, are critical parameters for the precision, robustness, and accuracy of IU titer determination. An added advantage of this assay is that it enables the concurrent determination of IU and transducing units (TU) by measuring the expression of a transgene product when testing recombinant viruses. The latter was demonstrated using a MVA vector carrying a human HER-2 gene fragment as model. Hence, this assay is very versatile in that it can be used to determine IU as well as multiple TU titers simultaneously. Furthermore, it can readily be adapted to other poxvirus vectors.

  13. 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.

  14. From the Lindlar catalyst to supported ligand-modified palladium nanoparticles: selectivity patterns and accessibility constraints in the continuous-flow three-phase hydrogenation of acetylenic compounds.

    PubMed

    Vilé, Gianvito; Almora-Barrios, Neyvis; Mitchell, Sharon; López, Núria; Pérez-Ramírez, Javier

    2014-05-12

    Site modification and isolation through selective poisoning comprise an effective strategy to enhance the selectivity of palladium catalysts in the partial hydrogenation of triple bonds in acetylenic compounds. The recent emergence of supported hybrid materials matching the stereo- and chemoselectivity of the classical Lindlar catalyst holds promise to revolutionize palladium-catalyzed hydrogenations, and will benefit from an in-depth understanding of these new materials. In this work, we compare the performance of bare, lead-poisoned, and ligand-modified palladium catalysts in the hydrogenation of diverse alkynes. Catalytic tests, conducted in a continuous-flow three-phase reactor, coupled with theoretical calculations and characterization methods, enable elucidation of the structural origins of the observed selectivity patterns. Distinctions in the catalytic performance are correlated with the relative accessibility of the active site to the organic substrate, and with the adsorption configuration and strength, depending on the ensemble size and surface potentials. This explains the role of the ligand in the colloidally prepared catalysts in promoting superior performance in the hydrogenation of terminal and internal alkynes, and short-chain alkynols. In contrast, the greater accessibility of the active surface of the Pd-Pb alloy and the absence of polar groups are shown to be favorable in the conversion of alkynes containing long aliphatic chains and/or ketone groups. These findings provide detailed insights for the advanced design of supported nanostructured catalysts.

  15. 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.

  16. Modified Grey Model and its application to groundwater flow analysis with limited hydrogeological data: a case study of the Nubian Sandstone, Kharga Oasis, Egypt.

    PubMed

    Mahmod, Wael Elham; Watanabe, Kunio

    2014-02-01

    Groundwater flow at Kharga Oasis, located in the western desert of Egypt, was previously analyzed using numerical models; however, the lack of basic data often limits the implementation of these models, as well as introducing a problem for model calibration and validation. The Grey Model (GM) was used to overcome these difficulties of data limitation and uncertainty of hydrogeological conditions. However, no clear theories exist for selecting the number of input model trends and the most suitable values of input parameters. Therefore, in the current study, a modification of the GM is newly proposed and called the Modified Grey Model (MGM) in an attempt to determine a process for selecting the best input models' trends with the appropriate values of input parameters to achieve acceptable fitting to observations. The sensitivity analysis results showed that the MGM produced more stable results than the GM using a wide range of values for input parameters. Moreover, the MGM reduced the calculation time required for fitting the measured piezometric level trends by 99.8%. Three development scenarios of groundwater withdrawal were proposed that involved either expanding the present extraction rate or redistributing the groundwater withdrawal over the recent working production wells (RWPWs). The results concluded that the groundwater table in the northern part of the oasis could be temporally recovered to an economical piezometric level; however, the table in the southern part is severely decreased. Therefore, new production wells are recommended to be constructed in the southern part far enough from the RWPWs.

  17. Effects of aeration and internal recycle flow on nitrous oxide emissions from a modified Ludzak-Ettinger process fed with glycerol.

    PubMed

    Song, Kang; Suenaga, Toshikazu; Harper, Willie F; Hori, Tomoyuki; Riya, Shohei; Hosomi, Masaaki; Terada, Akihiko

    2015-12-01

    Nitrous oxide (N2O) is emitted from a modified Ludzak-Ettinger (MLE) process, as a primary activated sludge system, which requires mitigation. The effects of aeration rates and internal recycle flow (IRF) ratios on N2O emission were investigated in an MLE process fed with glycerol. Reducing the aeration rate from 1.5 to 0.5 L/min increased gaseous the N2O concentration from the aerobic tank and the dissolved N2O concentration in the anoxic tank by 54.4 and 53.4 %, respectively. During the period of higher aeration, the N2O-N conversion ratio was 0.9 % and the potential N2O reducers were predominantly Rhodobacter, which accounted for 21.8 % of the total population. Increasing the IRF ratio from 3.6 to 7.2 decreased the N2O emission rate from the aerobic tank and the dissolved N2O concentration in the anoxic tank by 56 and 48 %, respectively. This study suggests effective N2O mitigation strategies for MLE systems.

  18. 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

  19. Method to rotate an endovascular device around the axis of a vessel using an external magnetic field.

    PubMed

    Florin, E; Rangwala, H S; Rudin, S

    2007-01-01

    A magnetic guidance methodology to rotate a device around the catheter axis is proposed. The specific medical application is to intracranial aneurysms. An endovascular device, the asymmetric stent, has a low porosity region that is rotated to cover the aneurysm neck so as to reduce the blood flow into and hence obliterate the aneurysm. The magnetic guidance system consists of a magnetic device attached to the asymmetric stent and an external homogeneous magnetic field of 0.1 T. This magnetic field puts a torque on the magnetic moment of the magnetic device, thereby rotating the stent for proper orientation. For the magnetic device with the required magnetic moment of 0.001 A m2, a cylindrical neodymium permanent magnet is proposed due to its favorable material characteristics while a coil electromagnet with iron core appears impractical due to demagnetizing effects.

  20. 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.

  1. 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

  2. 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

  3. First long-term evidence supporting endovascular repair of abdominal aortic aneurysms.

    PubMed

    Indes, Jeffrey E; Muhs, Bart E; Dardik, Alan

    2013-04-01

    The traditional method of treating abdominal aortic aneurysms with open surgical repair has been steadily replaced by endovascular repair, thought to be a more minimally invasive approach. It is not known, however, whether the endovascular approach is truly less invasive for operative physiology; in addition, this approach has a different spectrum of complications. As such, it is uncertain whether elective endovascular repair of nonruptured aortic aneurysms reduces long-term morbidity and mortality compared with traditional open approaches. In this article, the authors evaluate a recent publication investigating long-term outcomes of a prospective randomized multicenter trial evaluating patients with asymptomatic abdominal aortic aneurysms treated with either endovascular or open repair, and discuss the results in the context of current evidence. PMID:23570352

  4. An augmented reality framework for optimization of computer assisted navigation in endovascular surgery.

    PubMed

    Cheng, Irene; Shen, Rui; Moreau, Richard; Brizzi, Vicenzo; Rossol, Nathaniel; Basu, Anup

    2014-01-01

    Endovascular surgery is performed by placing a catheter through blood vessels. Due to the fragility of arteries and the difficulty in controlling a long elastic wire to reach the target region, training plays an extremely important role in helping a surgeon acquire the required complex skills. Virtual reality simulators and augmented reality systems have proven to be effective in minimally invasive surgical training. These systems, however, often employ pre-captured or computer-generated medical images. We have developed an augmented reality system for ultrasound-guided endovascular surgical training, where real ultrasound images captured during the procedure are registered with a pre-scanned phantom model to give the operator a realistic experience. Our goal is to extend the planning and training environment to deliver a system for computer assisted remote endovascular surgery where the navigation of a catheter can be controlled through a robotic device based on the guidance provided by an endovascular surgeon.

  5. Endovascular stents: a review of their use in peripheral arterial disease.

    PubMed

    Kudagi, Vinod S; White, Christopher J

    2013-06-01

    Technological advances in the past decade have shifted revascularization strategies from traditional open surgical approaches toward lower-morbidity percutaneous endovascular treatments for patients with lower extremity peripheral arterial disease (PAD). The continuing advances in stent design, more than any other advances, have fueled the growth of catheter-based procedures by improving the safety, durability, and predictability of percutaneous revascularization. Although the 2007 TransAtlantic Inter-Society Consensus (TASC) guidelines recommend endovascular therapy for type A and B aortoiliac and femoropopliteal lesions, recent developments in stent technology and increased experience of interventionists have suggested that a strategy of endovascular therapy first is appropriate in experienced hands for TASC type D lesions. The role of endovascular interventions is also expanding in the treatment of limb-threatening ischemia.

  6. 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.

  7. Through-and-through wire technique for endovascular damage control in traumatic proximal axillary artery transection.

    PubMed

    Rohlffs, Fiona; Larena-Avellaneda, Axel Antonio; Petersen, Jan Philipp; Debus, Eike Sebastian; Kölbel, Tilo

    2015-02-01

    Repair of blunt shoulder trauma with transection of the subclavian or proximal axillary artery poses a surgical challenge, especially in instable patients. Endovascular treatment for initial damage control in arterial transection has evolved as a promising technique to improve outcome, but technical success can be limited in cases of complete transection as the lesion cannot be passed by a guidewire. This report describes an endovascular approach using a through-and-through brachial-femoral wire to control complete traumatic transection of the proximal axillary artery in a hemodynamically unstable patient. Endovascular therapy is used as a bridging method for open surgical repair three days later under optimized conditions with an interdisciplinary team. The brachial-femoral guidewire technique helps to overcome limitations in endovascular therapy in patients with blunt traumatic transection of thoracic outlet arteries.

  8. 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

  9. Comparative Cost Analysis for Surgical and Endovascular Treatment of Unruptured Intracranial Aneurysms in South Korea

    PubMed Central

    Kim, Myungsoo; Lee, Joomi

    2015-01-01

    Objective A cost comparison of the surgical clipping and endovascular coiling of unruptured intracranial aneurysms (UIAs), and the identification of the principal cost determinants of these treatments. Methods This study conducted a retrospective review of data from a series of patients who underwent surgical clipping or endovascular coiling of UIAs between January 2011 and May 2014. The medical records, radiological data, and hospital cost data were all examined. Results When comparing the total hospital costs for surgical clipping of a single UIA (n=188) and endovascular coiling of a single UIA (n=188), surgical treatment [mean±standard deviation (SD) : ₩8,280,000±1,490,000] resulted in significantly lower total hospital costs than endovascular treatment (mean±SD : ₩11,700,000±3,050,000, p<0.001). In a multi regression analysis, the factors significantly associated with the total hospital costs for endovascular treatment were the aneurysm diameter (p<0.001) and patient age (p=0.014). For the endovascular group, a Pearson correlation analysis revealed a strong positive correlation (r=0.77) between the aneurysm diameter and the total hospital costs, while a simple linear regression provided the equation, y (₩)=6,658,630+855,250x (mm), where y represents the total hospital costs and x is the aneurysm diameter. Conclusion In South Korea, the total hospital costs for the surgical clipping of UIAs were found to be lower than those for endovascular coiling when the surgical results were favorable without significant complications. Plus, a strong positive correlation was noted between an increase in the aneurysm diameter and a dramatic increase in the costs of endovascular coiling. PMID:26180615

  10. Endovascular repair of a paraanastomotic aneurysm with inverted limb infrarenal bifurcated graft.

    PubMed

    Stringari, Carlo; Perkmann, Reinhold; Zaraca, Francesco

    2014-02-01

    A typical complication after conventional aortic prosthetic reconstruction is paraanastomotic aneurysm formation. Endovascular exclusion of paraanastomotic aneurysms has been shown to be a viable alternative to open surgical repair and to greatly reduce morbidity and mortality rates. We present a case report of asymptomatic proximal anastomotic pseudoaneurysm, measuring 4.5 cm in diameter, that was successfully treated by endovascular repair with a custom-made inverted limb infrarenal bifurcated graft.

  11. 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

  12. 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.

  13. Endovascular management of a carotid aneurysm into the sphenoid sinus presenting with epistaxis.

    PubMed

    Akkari, Mohamed; Gascou, Grégory; Trévillot, Vincent; Bonafé, Alain; Crampette, Louis; Machi, Paolo

    2015-12-01

    Non-traumatic cavernous internal carotid artery (ICA) aneurysms are rare, and favour the occurrence of massive recurrent epistaxis, which is associated with a high mortality rate. We report the case of a 67-year-old woman presenting a ruptured ICA aneurysm extending into the sphenoid sinus, revealed by epistaxis. Selective coil embolization of the aneurysm was performed. Flow-diverter stents were deployed in order to utterly exclude the aneurysm and prevent revascularization. Anti-platelet treatment was provided to lower the risk of in-stent thrombosis. A left frontal hematoma associated with a subarachnoid haemorrhage occurred at day 2. Outcome was favourable with no neurological sequelae, and no clinical recurrence of epistaxis occurred. A 4 months follow-up digital subtraction angiography showed a complete exclusion of the aneurysm. In addition, a magnetic resonance cerebral angiography at 16 months showed stable results. Thus, this two-stage endovascular procedure has proven its effectiveness in preventing epistaxis recurrence while preserving the ICA patency. PMID:26494406

  14. Biomechanical implications of excessive endograft protrusion into the aortic arch after thoracic endovascular repair.

    PubMed

    Rinaudo, Antonino; Raffa, Giuseppe Maria; Scardulla, Francesco; Pilato, Michele; Scardulla, Cesare; Pasta, Salvatore

    2015-11-01

    Endografts placed in the aorta for thoracic endovascular aortic repair (TEVAR) may determine malappositioning to the lesser curvature of the aortic wall, thus resulting in a devastating complication known as endograft collapse. This premature device failure commonly occurs in young individuals after TEVAR for traumatic aortic injuries as a result of applications outside the physical conditions for which the endograft was designed. In this study, an experimentally-calibrated fluid-structure interaction (FSI) model was developed to assess the hemodynamic and stress/strain distributions acting on the excessive protrusion extension (PE) of endografts deployed in four young patients underwent TEVAR. Endograft infolding was experimentally measured for different hemodynamic scenarios by perfusion testing and then used to numerically calibrate the mechanical behavior of endograft PE. Results evinced that the extent of endograft can severely alter the hemodynamic and structural loads exerted on the endograft PE. Specifically, PE determined a physiological aortic coarctation into the aortic arch characterized by a helical flow in the distal descending aorta. High device displacement and transmural pressure across the stent-graft wall were found for a PE longer than 21 mm. Finally, marked intramural stress and principal strain distributions on the protruded segment of the endograft wall may suggest failure due to material fatigue. These critical parameters may contribute to the endograft collapse observed clinically and can be used to design new devices more suitable for young individuals to be treated with an endoprosthesis for TEVAR of blunt traumatic aortic injuries.

  15. 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.

  16. 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.

  17. 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

  18. 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

  19. 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

  20. Computational fluid dynamics evaluation of the cross-limb stent graft configuration for endovascular aneurysm repair.

    PubMed

    Shek, Tina L T; Tse, Leonard W; Nabovati, Aydin; Amon, Cristina H

    2012-12-01

    The technique of crossing the limbs of bifurcated modular stent grafts for endovascular aneurysm repair (EVAR) is often employed in the face of splayed aortic bifurcations to facilitate cannulation and prevent device kinking. However, little has been reported about the implications of cross-limb EVAR, especially in comparison to conventional EVAR. Previous computational fluid dynamics studies of conventional EVAR grafts have mostly utilized simplified planar stent graft geometries. We herein examined the differences between conventional and cross-limb EVAR by comparing their hemodynamic flow fields (i.e., in the "direct" and "cross" configurations, respectively). We also added a "planar" configuration, which is commonly found in the literature, to identify how well this configuration compares to out-of-plane stent graft configurations from a hemodynamic perspective. A representative patient's cross-limb stent graft geometry was segmented using computed tomography imaging in Mimics software. The cross-limb graft geometry was used to build its direct and planar counterparts in SolidWorks. Physiologic velocity and mass flow boundary conditions and blood properties were implemented for steady-state and pulsatile transient simulations in ANSYS CFX. Displacement forces, wall shear stress (WSS), and oscillatory shear index (OSI) were all comparable between the direct and cross configurations, whereas the planar geometry yielded very different predictions of hemodynamics compared to the out-of-plane stent graft configurations, particularly for displacement forces. This single-patient study suggests that the short-term hemodynamics involved in crossing the limbs is as safe as conventional EVAR. Higher helicity and improved WSS distribution of the cross-limb configuration suggest improved flow-related thrombosis resistance in the short term. However, there may be long-term fatigue implications to stent graft use in the cross configuration when compared to the direct

  1. 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

  2. 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.

  3. Long-term Follow-up Study of Endovascularly Treated Intracranial Aneurysms

    PubMed Central

    Pyysalo, L.M.; Keski-Nisula, L.H.; Niskakangas, T.T.; Kähärä, V.J.; Öhman, J.E.

    2010-01-01

    Summary Long-term follow-up studies after endovascular treatment for intracranial aneurysm are still rare and inconclusive. The aim of this study was to assess long-term clinical and angiographic outcome of patients with endovascularly treated aneurysms. The Clinical outcome of all 185 patients with endovascularly treated aneurysms were analyzed and 77 out of 122 surviving patients were examined with MRI and MRA nine to 16 years (mean 11 years) after the initial endovascular treatment. Sixty-three patients were deceased at the time of follow-up. The cause of death was aneurysm- related in 34 (54%) patients. The annual re- bleeding rate from the treated aneurysms was 1.3% in the ruptured group and 0.1% in the unruptured group. In long-term follow-up MRA 18 aneurysms (53%) were graded as complete, 11 aneurysms (32%) had neck remnants and five aneurysms (15%) were incompletely occluded in the ruptured group. Occlusion grade was lower in the unruptured group with 20 an- eurysms (41%) graded as complete, 11 (22%) had neck remnants and 18 (37%) were incomplete. However, only three aneurysms were unstable during the follow-up period and needed retreatment. Endovascular treatment of unruptured aneu- rysms showed incomplete angiographic outcome in 37% of cases. However, annual bleeding rate was as low as 0.1%. Endovascular treatment of ruptured aneurysms showed incomplete angiographic outcome in 15% of cases and the annual rebleeding rate was 1.3%. PMID:21162766

  4. Combined Endovascular and Microsurgical Procedures as Complementary Approaches in the Treatment of a Single Intracranial Aneurysm

    PubMed Central

    Lim, Yong Cheol; Chung, Joonho

    2008-01-01

    Objective Both endovascular coil embolization and microsurgical clipping are now firmly established as treatment options for the management of cerebral aneurysms. Moreover, they are sometimes used as complementary approaches each other. This study retrospectively analyzed our experience with endovascular and microsurgical procedures as complementary approaches in treating a single aneurysm. Methods Nineteen patients with intracranial aneurysm were managed with both endovascular and microsurgical treatments. All of the aneurysms were located in the anterior circulation. Eighteen patients presented with SAH, and 14 aneurysms had diameters of less than 10 mm, and five had diameters of 10-25 mm. Results Thirteen of the 19 patients were initially treated with endovascular coil embolization, followed by microsurgical management. Of the 13 patients, 9 patients had intraprocedural complications during coil embolization (intraprocedural rupture, coil protrusion, coil migration), rebleeding with regrowth of aneurysm in two patients, residual sac in one patient, and coil compaction in one patient. Six patients who had undergone microsurgical clipping were followed by coil embolization because of a residual aneurysm sac in four patients, and regrowth in two patients. Conclusion In intracranial aneurysms involving procedural endovascular complications or incomplete coil embolization and failed microsurgical clipping, because of anatomical and/or technical difficulties, the combined and complementary therapy with endovascular coiling and microsurgical clipping are valuable in providing the best outcome. PMID:19096540

  5. Long-Term Follow-Up Study of Endovascularly Treated Intracranial Aneurysms

    PubMed Central

    Pyysalo, L.M.; Keski-Nisula, L.H.; Niskakangas, T.T.; Kähärä, V.J.; Öhman, J.E.

    2010-01-01

    Summary Long-term follow-up studies after endovascular treatment for intracranial aneurysm are still rare and inconclusive. The aim of this study was to assess the long-term clinical and angiographic outcome of patients with endovascularly treated aneurysms. The clinical outcome of all 185 patients with endovascularly treated aneurysms were analyzed and 77 out of 122 surviving patients were examined with MRI and MRA nine to 16 years (mean 11 years) after the initial endovascular treatment. Sixty-three patients were deceased at the time of follow-up. The cause of death was aneurysm-related in 34 (54ċ) patients. The annual rebleeding rate from the treated aneurysms was 1.3% in the ruptured group and 0.1% in the unruptured group. In long-term follow-up MRA 18 aneurysms (53%) were graded as complete, 11 aneurysms (32%) had neck remnants and five aneurysms (15%) were incompletely occluded in the ruptured group. The occlusion grade was lower in the unruptured group with 20 aneurysms (41%) graded as complete, 11 (22%) had neck remnants and 18 (37%) were incomplete. However, only three aneurysms were unstable during the follow-up period and needed retreatment. Endovascular treatment of unruptured aneurysms showed incomplete angiographic outcome in 37% of cases. However, the annual bleeding rate was as low as 0.1%. Endovascular treatment of ruptured aneurysms showed incomplete angiographic outcome in 15% of cases and the annual rebleeding rate was 1,3%. PMID:20977853

  6. Adding an endovascular aortic surgery program to a rural regional medical centre

    PubMed Central

    Marelli, Daniel; Woo, Edward; Watson, Michael; Fedalen, Paul; Wang, Grace; Stallings, Megan; Fairman, Ronald; Mannion, John

    2013-01-01

    Background Abdominal aortic aneurysms requiring surgical intervention are generally treated by endovascular means. Such procedures are not always offered in rural hospitals, possibly leaving patients underserved. We reviewed our experience initiating an endoaortic surgery program. Methods A surgeon in a rural centre was credentialed to perform endovascular aortic aneurysm repair through collaboration with a university centre and was proctored locally for the first 5 abdominal aneurysm repairs. Web-based image storage was used to review complex cases as part of an ongoing partnership. Referred patients were screened for multiple aneurysms and underwent long-term monitoring. Results In all, 160 patients were evaluated for 176 aortic pathologies. Twenty-five patients (17 men) aged 55–89 years underwent 26 endovascular abdominal (n = 23) or thoracic (n = 3) aortic procedures. Emergent endovascular procedures were not performed. There were no operative deaths, requirements for dialysis or conversions to open repair. Two endoleaks required early reintervention. The median length of stay in hospital for endovascular procedures was 2.5 days. Chronic endoleaks were observed in 7 patients. An additional 8 patients underwent open abdominal aneurysm repair locally and 15 patients were referred to the university program. Conclusion Creation of an endovascular aortic surgery program in a rural hospital is feasible through collaboration with a high-volume centre. Patient safety is enhanced by obtaining second opinions using web-based image review. Most interventions are for abdominal aortic aneurysms, but planning for a comprehensive aortic clinic is preferable. PMID:24067525

  7. Thrombosis of a descending thoracic aortic endovascular stent graft in a patient with factor V Leiden: case report

    PubMed Central

    2014-01-01

    We present a case of a 14 year old Caucasian male who underwent initially successful endovascular repair of a traumatic injury to the descending thoracic aorta. The patient had undiagnosed Factor V Leiden at the time of the endovascular repair. He later presented with thrombosis of the endovascular stent graft, necessitating open removal of the stent graft and replacement of the involved aorta with a Dacron graft. PMID:24618347

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

    PubMed Central

    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

  9. Effect of Cilostazol Following Endovascular Intervention for Peripheral Artery Disease.

    PubMed

    Nanto, Kiyonori; Iida, Osamu; Takahara, Mitsuyoshi; Soga, Yoshimitsu; Suzuki, Kenji; Hirano, Keisuke; Kawasaki, Daizo; Shintani, Yoshiaki; Suematsu, Nobuhiro; Yamaoka, Terutoshi; Uematsu, Masaaki

    2015-09-01

    Efficacy of endovascular therapy (EVT) with nitinol stents for femoropopliteal (FP) lesions is limited by restenosis. Oral cilostazol reduces angiographic restenosis rate; however, treatment duration remains unclear. In a retrospective analysis of a multicenter database of 3471 consecutive limbs in 2737 patients (mean age: 72 ± 9 years; 61% diabetic; and 26% on regular dialysis) undergoing EVT for FP lesions between January 2004 and December 2011, we compared Kaplan-Meier estimated primary patency after EVT followed or not by cilostazol treatment. We used Cox hazard regression analysis to assess temporal association between cilostazol treatment and post-EVT restenosis. Five-year primary patency was higher in the cilostazol group than in the noncilostazol group (57% vs 47%, P < .0001). Cilostazol treatment was inversely associated with restenosis for the first 2 years following EVT (P < .05); however, no significant association was observed thereafter. Cilostazol use therefore appears efficacious in preventing restenosis up to 2 years after EVT for FP lesions.

  10. 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

  11. 3D guide wire tracking for navigation in endovascular interventions

    NASA Astrophysics Data System (ADS)

    Baert, Shirley A.; van Walsum, Theo; Niessen, Wiro J.

    2004-05-01

    A method is presented to track the guide wire during endovascular interventions and to visualize it in 3D, together with the vasculature of the patient. The guide wire is represented by a 3D spline whose position is optimized using internal and external forces. For the external forces, the 3D spline is projected onto the biplane projection images that are routinely acquired. Feature images are constructed based on the enhancement of line-like structures in the projection images. A threshold is applied to this image such that if the probability of a pixel to be part of the guide wire is sufficiently high this feature image is used, whereas outside this region a distance transform is computed to improve the capture range of the method. In preliminary experiments, it is shown that some of the problems of the 2D tracking which where presented in previous work can successfully be circumvented using the 3D tracking method.

  12. Persistent Type I Endoleak after Endovascular Treatment with Chimney Technique

    PubMed Central

    Azevedo, Ana Isabel; Braga, Pedro; Rodrigues, Alberto; Ferreira, Nuno; Fonseca, Marlene; Dias, Adelaide; Gama Ribeiro, Vasco

    2016-01-01

    Thoracic endovascular aortic repair (TEVAR) is increasingly used in the treatment of acute type B aortic dissection. Type Ia endoleaks are a common complication of the procedure, but its clinical significance and the best treatment strategy remain poorly defined. We present a case of a type Ia endoleak following TEVAR in the treatment of acute type B aortic dissection. Chimney technique approach was used in an attempt to seal the endoleak. Although technical success was suboptimal, the patient remained clinically stable and event free. Data regarding the natural course and management of type Ia endoleaks following TEVAR for aortic dissection are sparse. Future research is required to establish the clinical and technical determinants of the need to treat these endoleaks and the best treatment strategy. PMID:27703967

  13. [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

  14. 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

  15. 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

  16. Endovascular Stent-Graft Treatment of Giant Celiac Artery Pseudoaneurysm

    PubMed Central

    Tuncel, Sedat Alpaslan; Gülcü, Aytaç; Yılmaz, Erdem; Çiftçi, Taner; Göktay, Ahmet Yiğit

    2015-01-01

    Summary Background Visceral artery aneurysms (VAAs) comprise an uncommon but life-threatening vascular disease. When rupture is the first clinical presentation, mortality rate reaches 70%. Increased use of cross-sectional imaging has led to a greater rate of diagnosis (40–80%) of asymptomatic VAAs. In the past, surgery was the treatment of choice for VAAs carrying high risk of mortality and morbidity. Case Report A 22-year-old man, who had undergone gastric, pancreatic and aortic surgery 2.5 years earlier, presented with progressive abdominal pain. Multidetector computed tomography scan revealed an 8-cm celiac pseudoaneurysm. We report a giant celiac pseudoaneurysm treated with stent-graft implantation. Conclusions Endovascular treatment of VAA is a safe and effective method alternative to surgery. PMID:26236417

  17. 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

  18. 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

  19. [Endovascular treatment of spinal dorsal intradural arteriovenous fistulas].

    PubMed

    Santos-Franco, Jorge Arturo; Collado-Arce, María Griselda Lizbeth; Dávila-Romero, Julio César; Saavedra-Andrade, Rafael; Sandoval-Balanzario, Miguel Antonio

    2015-01-01

    Introducción: las fístulas arteriovenosas intradurales dorsales espinales (FAVIDE) son lesiones poco frecuentes y complejas que son subdiagnósticadas y condicionan discapacidad. El objetivo es presentar nuestra experiencia en el manejo endovascular. Métodos: estudio ambispectivo de pacientes con FAVIDE, tratados mediante terapia endovascular (TEV) con n-butil-cianoacrilato en el periodo de 2007 a 2013. Resultados: se incluyeron 15 pacientes con edad media de 37 años. En 12 casos la presentación fue progresiva e insidiosa en un lapso de entre 6 meses y un año, mientras que 3 presentaron hemorragia. La lesión tuvo localización torácica en 73 % de los casos, lumbar en 20 % y cervical en 7 %. Previo al tratamiento observamos discapacidad de grados 5 y 4 en 73 %, y 67 % tenían alteraciones de la micción de grado 3. Como complicaciones, solo una paciente tuvo deterioro del estado de alerta transitorio 6 horas después del procedimiento. Se encontró una mejoría hacia los grados 1 y 2 de discapacidad, a las 48 horas, 3 y 6 meses, de 53 %, 73 % y 87 %, respectivamente. Conclusiones: con la TEV se tiene un tiempo quirúrgico corto, el volumen de hemorragia es bajo y la estancia hospitalaria es corta, respecto de otras técnicas quirúrgicas. La TEV es un procedimiento seguro y con efectividad significativa en el tratamiento de FAVIDE. Esta es la primera serie de casos tratados con TEV en México.

  20. 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.

  1. 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.

  2. 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.

  3. Endovascular treatment of aortic aneurysms: state of the art.

    PubMed

    Eliason, Jonathan L; Upchurch, Gilbert R

    2009-04-01

    Abdominal aortic aneurysms (AAAs) continue to be a leading cause of death, with increasing incidence and prevalence. Endovascular aneurysm repair (EVAR) now represents the most common method of AAA repair in the United States. Ongoing improvements in endovascular stent-graft technology have occurred since the first published report of EVAR in 1991. These improvements have led to multiple US Food and Drug Administration-approved devices, streamlined operative techniques, and extended applicability of EVAR. Despite these facts, basic anatomic considerations still eliminate many patients from being offered EVAR. Distinct advantages of EVAR over open repair have been demonstrated, including a less invasive operative exposure, decreased transfusion requirements, shortened intensive care unit and hospital stay, and decreased perioperative mortality. It is our opinion that in 2009, anatomically suitable patients should be offered EVAR as first-line therapy, except for the less common scenario of the young and fit patient, for which open repair should be strongly considered. Use of EVAR for ruptured AAAs also has shown promise, yielding survival results commensurate with the best single-center results with open repair for rupture. However, questions remain regarding the long-term efficacy of EVAR in preventing aneurysm-related death for all patients treated with this technique. As device improvements and technical advances continue, it is reasonable to expect that long-term results will improve as well. Furthermore, the advent of fenestrated and multi-branch endograft technology is expanding indications, and will continue to enlarge the percentage of patients who will be considered acceptable candidates for EVAR. Lastly, randomized clinical trials are under way to determine whether the generally accepted threshold of 5.5 cm for elective open AAA repair should be decreased in patients who are candidates for EVAR. Until further data emerge, standard guidelines for elective

  4. Predictors of Neurological Deficit after Endovascular Treatment of Cerebral Arteriovenous Malformations and Functional Repercussions in Prospective Follow-Up

    PubMed Central

    Jordan, Jose; Llibre, Juan Carlos; Vazquez, Frank

    2014-01-01

    Summary Endovascular therapy is a well-established approach to the treatment of cerebral arteriovenous malformations (AVMs). The objective of this study was to determine the predictive factors of neurological deficit following endovascular procedures. Seventy-one patients with cerebral AVMs who underwent 147 embolization sessions from 2006 to 2011 were followed up prospectively (average 31.1 ± 17.5 months). Functional neurological condition was documented by means of the modified Rankin scale. Factors found to be predictors of neurological deficit were the partial obstruction of drainage veins (OR = 197.6; IC = 2.76 -1416.0; P = 0.015), a positive result in the Propofol test (OR = 50.2; IC = 6.18 - 566.5; P = 0.000), AVM diameter under 3 cm (OR = 21.3; IC: 1.71 − 265.6; P = 0.018), the presence of intranidal aneurysms (OR = 11.2; IC = 1.09 − 114.2; P = 0.042), the absence of post-procedure hypotension (OR = 10.2; IC = 1.35 − 77.7; P = 0.003), deep venous drainage (OR = 7.14; IC = 1.15 − 44.4; P = 0.035), and devascularization in excess of 40% per session (OR = 3.3; IC = 1.11 − 16.8; P = 0.056). Fifty-six patients (78.9%) did not experience changes in their neurological condition after the treatment and 13 patients (18.3%) showed a new neurological deficit related to the treatment; 95.8 % of the patients did not show significant long-term incapacity. Partial obstruction of drainage veins, small AVMs, intranidal aneurysms, faulty hemodynamic control and extensive devascularization were found to be predictors of neurological deficit. A significant number of patients with neurological deficit improved in the long term. PMID:25489896

  5. Intraarterial administration of norcantharidin attenuates ischemic stroke damage in rodents when given at the time of reperfusion: novel uses of endovascular capabilities.

    PubMed

    Khan, Imad S; Odom, Mitchell; Ehtesham, Moneeb; Colvin, Daniel; Quarles, C Chad; McLaughlin, BethAnn; Singer, Robert J

    2016-07-01

    OBJECT Matrix metalloprotease-9 (MMP-9) plays a critical role in infarct progression, blood-brain barrier (BBB) disruption, and vasogenic edema. While systemic administration of MMP-9 inhibitors has shown neuroprotective promise in ischemic stroke, there has been little effort to incorporate these drugs into endovascular modalities. By modifying the rodent middle cerebral artery occlusion (MCAO) model to allow local intraarterial delivery of drugs, one has the ability to mimic endovascular delivery of therapeutics. Using this model, the authors sought to maximize the protective potential of MMP-9 inhibition by intraarterial administration of an MMP-9 inhibitor, norcantharidin (NCTD). METHODS Spontaneously hypertensive rats were subjected to 90-minute MCAO followed immediately by local intraarterial administration of NCTD. The rats' neurobehavioral performances were scored according to the ladder rung walking test results and the Garcia neurological test for as long as 7 days after stroke. MRI was also conducted 24 hours after the stroke to assess infarct volume and BBB disruption. At the end of the experimental protocol, rat brains were used for active MMP-9 immunohistochemical analysis to assess the degree of MMP-9 inhibition. RESULTS NCTD-treated rats showed significantly better neurobehavioral scores for all days tested. MR images also depicted significantly decreased infarct volumes and BBB disruption 24 hours after stroke. Inhibition of MMP-9 expression in the ischemic region was depicted on immunohistochemical analysis, wherein treated rats showed decreased active MMP-9 staining compared with controls. CONCLUSIONS Intraarterial NCTD significantly improved outcome when administered at the time of reperfusion in a spontaneously hypertensive rat stroke model. This study suggests that supplementing endovascular revascularization with local neuroprotective drug therapy may be a viable therapeutic strategy. PMID:26544777

  6. Surveillance of patients after abdominal aortic aneurysm repair with endovascular grafting or conventional treatment.

    PubMed

    Raithel, D

    1998-12-01

    At Nuremberg Southern Hospital we have been using endovascular therapy for aortic aneurysms for the past 3 years. Between August 1994 and August 1997, 193 patients with infrarenal aortic aneurysms were treated with endovascular stent grafts. Besides using commercially available modular systems of the Stentor type (MinTec/Vanguard*, Boston Scientific) we also participated in a multicenter study implanting EGS devices (EVT in 65 patients). Follow-up examinations must strive to detect thrombotic complications as well as endoleaks with high sensitivity and specificity. To avoid aneurysm rupture significant increase in aneurysm diameter must be detected in a timely fashion to select patients for additional corrective endovascular procedures or conversion to open surgical therapy. A close follow-up regimen therefore is absolutely mandatory for all patients undergoing endovascular aortic grafting, particularly when new prosthetic devices are being introduced. Prosthetic devices that have been adequately tested using controlled study designs and are commercially available may be followed-up using a standardized follow up scheme as delineated. Particularly during the first postoperative year color duplex with use of an intravenous ultrasound enhancing agent has been used successfully to detect even minor endoleaks originating from retrograde perfusion via aortic side branches (lumbar or inferior mesenteric artery). Only patients with documented endoleaks or suspected outflow obstruction requiring further intervention need to undergo diagnostic arteriography. After conventional aneurysm repair yearly duplex scans are usually sufficient to follow the normal patient. Patients who have undergone endovascular therapy, however need to be followed much closer using duplex as well as abdominal CT scans. This will logically result in significantly higher follow up costs. Periinterventional costs of endovascular aortic reconstruction currently exceed those of conventional aortic

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. The TEAM trial: Safety and efficacy of endovascular treatment of unruptured intracranial aneurysms in the prevention of aneurysmal hemorrhages: A randomized comparison with indefinite deferral of treatment in 2002 patients followed for 10 years

    PubMed Central

    Raymond, Jean; Molyneux, Andrew J; Fox, Allan J; Johnston, S Claiborne; Collet, Jean-Paul; Rouleau, Isabelle

    2008-01-01

    The management of patients with unruptured aneurysms remains controversial. Patients with unruptured aneurysms may suffer intracranial haemorrhage, but the incidence of this event is still debated; endovascular treatment may prevent rupture, but involves immediate risks. Hence, the balance of risks and benefits of endovascular treatment is uncertain. Here, we report the design of the TEAM trial, the first international, randomized, controlled trial comparing conservative management with endovascular treatment. Primary endpoint is mortality and morbidity (modified Rankin Score ≥ 3) from intracranial haemorrhage or treatment. Secondary endpoints include incidence of hemorrhagic events, morbidity related to endovascular coiling, morphological results, overall clinical outcome and quality of life. Statistical tests compare between probabilities at 5- and 10-years of 1/mortality from haemorrhage related to the lesion, excluding per-operative complications; 2/mortality from haemorrhage or from complications of treatment; 3/combined disease or treatment related mortality and morbidity in the absence of other causes of death or disability. The study will be conducted in 60 international centres and will enrol 2,002 patients equally divided between the two groups, a size sufficient to achieve 80% power at a 0.0167 significance to detect differences in 1) disease or treatment-related poor outcomes from 7–9% to 3–5%; 2) overall mortality from 16 to 11%. Duration of the study is 14 years, the first three years being for patient recruitment plus a minimum of 10 years of follow-up. The TEAM trial thus offers a means to reconcile the introduction of a new approach with the necessity to acknowledge uncertainties. Current Controlled Trials ISRCTN62758344 PMID:18631395

  12. 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.

  13. [Experience with the ovations stent graft system for totally percutaneous endovascular repair of the infrarenal portion of the abdominal aorta].

    PubMed

    Frantsevich, A M; Tsygankov, V N; Pokrovskiĭ, A V

    2015-01-01

    Presented in the article are clinical cases of successful totally percutaneous endovascular repair of the infrarenal portion of the abdominal aorta using the Ovation Prime ultra-low profile stent graft in high-surgical-risk patients, yielding good immediate and short-term results, thus demonstrating new possibilities in endovascular treatment of aneurysms of the infrarenal portion of the abdominal aorta. PMID:26673299

  14. Neuroprotective role of neurophysiological monitoring during endovascular procedures in the spinal cord.

    PubMed

    Sala, F; Niimi, Y; Berenstein, A; Deletis, V

    2001-06-01

    The endovascular treatment of spinal vascular malformations places the spinal cord at risk for ischemia. When these procedures are performed using general anesthesia, the neurophysiological monitoring methods currently available provide the only means by which to assess the functional integrity of sensory and motor pathways. Neurophysiological monitoring allows a warning for the neuroradiologist of impending irreversible neurological damage so that action may be taken for the prompt restoration of adequate spinal cord perfusion. Muscle motor evoked potentials (mMEPs) better reflect spinal cord perfusion in the anterior spinal artery territory than do somatosensory evoked potentials (SEPs), although their use during spinal endovascular procedures remains anecdotal in the literature. In the study reported here we assessed: (1) the feasibility of intraoperative neurophysiological monitoring, (2) the role of provocative tests with Amytal and Xylocaine, and (3) the specific but complementary role played by SEPs and mMEPs, during endovascular embolization of spinal vascular malformations and tumors. The results suggest that: (1) neurophysiological monitoring is feasible during most endovascular procedures in the spine and spinal cord under general anesthesia, (2) provocative tests enhance the safety of the procedure, (3) mMEPs are more feasible than SEPs and more sensitive than SEPs to provocative tests. We strongly suggest the use of multimodal neurophysiological monitoring and provocative tests during the endovascular treatment of spinal and spinal cord vascular lesions.

  15. 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

  16. 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.

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

    PubMed

    Kezurer, Noa; Farah, Nairouz; Mandel, Yossi

    2016-08-18

    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.

  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. 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

  20. Intra-aortic balloon pumping reduces the increased arterial load caused by acute cardiac depression, modifying central and peripheral load determinants in a time- and flow-related way.

    PubMed

    Bia, Daniel; Cabrera-Fischer, Edmundo I; Zócalo, Yanina; Armentano, Ricardo L

    2012-09-01

    The mechanisms that explain intra-aortic balloon pumping (IABP) effects are not completely understood, and attributing them only to pressure-associated changes in cardiac function would be an oversimplification. Since IABP modifies the aortic and systemic blood-flow pattern, flow-related effects could be expected. To characterize effects of acute heart failure (AHF) on the arterial biomechanics; IABP effects on the arterial biomechanics during AHF, and their potential time-dependence; the association between hemodynamics and biomechanical changes during AHF and IABP. Sheep (n = 6) aortic pressure, flow, and diameter were measured: (1) before (Basal) and (2) 1-3 (HF(1-3)) and 28-30 (HF(28-30)) min after starting halothane to induce AHF; and (3) at specific times (1-3, 14-15 and 28-30 min) during IABP assistance. Calculus: aortic characteristic impedance (Z(c)), beta stiffness (β), incremental (E(INC)) and pressure-strain elastic modulus (E(P)); total arterial compliance (C(G)), total systemic vascular resistance and wave propagation parameters. (1) AHF resulted in an acute increase in aortic and systemic stiffness (HF(28-30) % changes with respect to Basal conditions: β +217%, E (P) +143%, E(INC) +101%, Z(c) +52%, C(G) -13%), associated with the reduction in the aortic blood flow; (2) during AHF IABP resulted in acute beneficial changes aortic and systemic biomechanics (% changes in IABP(1-3) with respect HF(28-30): β -62%, E(P) -68%, E (INC) -66%, Z(c) -38%, C(G) 66%), and in wave propagation parameters, (3) IABP-related changes were time-dependent and associated with changes in aortic blood flow. Aortic and systemic biomechanical and impedance properties are detrimentally modified during AHF, being the changes rapidly reverted during IABP. IABP-related beneficial changes in arterial biomechanics were time-dependent and associated with IABP capability to increase blood flow.

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. Design and biocompatibility of endovascular aneurysm filling devices

    DOE PAGES

    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

  6. 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.

  7. 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

  8. Metallic Zinc Exhibits Optimal Biocompatibility for Bioabsorbable Endovascular Stents

    PubMed Central

    Bowen, Patrick K.; Guillory, Roger J.; Shearier, Emily R.; Seitz, Jan-Marten; Drelich, Jaroslaw; Bocks, Martin; Zhao, Feng; Goldman, Jeremy

    2015-01-01

    Although corrosion resistant bare metal stents are considered generally effective, their permanent presence in a diseased artery is an increasingly recognized limitation due to the potential for long-term complications. We previously reported that metallic zinc exhibited an ideal biocorrosion rate within murine aortas, thus raising the possibility of zinc as a candidate base material for endovascular stenting applications. This study was undertaken to further assess the arterial biocompatibility of metallic zinc. Metallic zinc wires were punctured and advanced into the rat abdominal aorta lumen for up to 6.5 months. This study demonstrated that metallic zinc did not provoke responses that often contribute to restenosis. Low cell densities and neointimal tissue thickness, along with tissue regeneration within the corroding implant, point to optimal biocompatibility of corroding zinc. Furthermore, the lack of progression in neointimal tissue thickness over 6.5 months or the presence of smooth muscle cells near the zinc implant suggest that the products of zinc corrosion may suppress the activities of inflammatory and smooth muscle cells. PMID:26249616

  9. Metallic zinc exhibits optimal biocompatibility for bioabsorbable endovascular stents.

    PubMed

    Bowen, Patrick K; Guillory, Roger J; Shearier, Emily R; Seitz, Jan-Marten; Drelich, Jaroslaw; Bocks, Martin; Zhao, Feng; Goldman, Jeremy

    2015-11-01

    Although corrosion resistant bare metal stents are considered generally effective, their permanent presence in a diseased artery is an increasingly recognized limitation due to the potential for long-term complications. We previously reported that metallic zinc exhibited an ideal biocorrosion rate within murine aortas, thus raising the possibility of zinc as a candidate base material for endovascular stenting applications. This study was undertaken to further assess the arterial biocompatibility of metallic zinc. Metallic zinc wires were punctured and advanced into the rat abdominal aorta lumen for up to 6.5months. This study demonstrated that metallic zinc did not provoke responses that often contribute to restenosis. Low cell densities and neointimal tissue thickness, along with tissue regeneration within the corroding implant, point to optimal biocompatibility of corroding zinc. Furthermore, the lack of progression in neointimal tissue thickness over 6.5months or the presence of smooth muscle cells near the zinc implant suggest that the products of zinc corrosion may suppress the activities of inflammatory and smooth muscle cells.

  10. 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.

  11. 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.

  12. Tailoring the endovascular management of transplant renal artery stenosis.

    PubMed

    Biederman, D M; Fischman, A M; Titano, J J; Kim, E; Patel, R S; Nowakowski, F S; Florman, S; Lookstein, R A

    2015-04-01

    In this study we analyze the different types of endovascular interventions (EVIs) in de novo transplant renal artery stenosis (TRAS) and its anatomical subtypes to examine any variation in recovery of allograft function, blood pressure control, EVI patency and allograft survival with respect to EVI type (DES: drug-eluting stent, BMS: bare-metal stent, PTA: percutaneous transluminal angioplasty). Forty-five patients underwent a total of 50 primary EVIs (DES: 18, BMS: 26, PTA: 6). Patients were stratified according to medical co-morbidities, graft characteristics, biopsy results, clinical presentation and TRAS anatomic subtypes (anastomotic: 26, postanastomotic: 17, bend-kink: 2). There was significant improvement in allograft function and mean arterial blood pressure (MAP) control across all interventions (pre-EVI-creatinine [CR]: 2.8 ± 1.4, post-EVI-Cr: 2.1 ± 0.7, p < 0.001; pre-EVI-MAP: 117 ± 16, post-EVI-MAP: 112 ± 17, p = 0.03) with no significant difference among EVI types. There was no significant difference in allograft survival with respect to EVI type. Patency was significantly higher in EVIs performed with DES and BMS compared to PTA (p = 0.001). In the postanastomotic TRAS subtype, patency rates were significantly higher in DES compared to BMS (p = 0.012) in vessels of comparable reference diameter (≤5 mm). PMID:25703133

  13. 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.

  14. 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.

  15. [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

  16. 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.

  17. Standard procedures of endovascular treatment for vascular access stenosis in our facility - clinical usefulness of ultrasonography.

    PubMed

    Sato, Takashi; Tsuboi, Masato; Onogi, Takeshi; Miwa, Naofumi; Sakurai, Hiroshi; Ookubo, Kentarou; Matsubara, Chieko; Kasuga, Hirotake

    2015-11-01

    In Japan, the number of patients receiving dialysis is 314,180 at the end of 2013 and 97% are treated with hemodialysis. And the mean age of patients and the percentage of diabetes have been increasing. For this reason, preparations of a new vascular access (VA) and its long-term maintenance have become difficult. In the guidelines by the Japanese Society for Dialysis Therapy (JSDT), endovascular treatment (ET) is positioned as the first line for VA stenosis. The procedure of ET itself is very simple. The revision of Japanese health insurance set an expensive technical fee for ET in 2012. It also added a restriction by which the claims for both technical and material fees would be denied, if the treatment was performed within 3 months after a previous treatment. This makes determination of best treatment timing more important. The functional evaluation using ultrasonography (US) is a useful monitoring index for determination of the ET timing for patients with stenosis. We investigated the cumulative relative frequency of flow volume (FV) and resistant index (RI) of brachial artery in arteriovenous graft (AVG) and arteriovenous fistula (AVF) cases with access failures. As a result, the cut-off values of FV and RI in AVG were 480 mL/min and 0.57, and in AVF were 354 mL/min and 0.61, respectively. Therefore we determine the treatment timing based on these results. Since 2012, active monitoring using US could have decreased the number of treatment patients by 100 per year. This meant that objective evaluation by US enabled treatments at a more suitable time to promote the proper use of medical expenses for EV treatment.

  18. Robot-assisted fenestrated endovascular aneurysm repair (FEVAR) using the Magellan system.

    PubMed

    Riga, Celia V; Bicknell, Colin D; Rolls, Alexander; Cheshire, Nicholas J; Hamady, Mohamad S

    2013-02-01

    A 67-year-old man underwent robot-assisted three-vessel fenestrated endovascular aneurysm repair (FEVAR) for a 7.3-cm juxtarenal aneurysm. The 6-F robotic catheter was manipulated from a remote workstation, away from the radiation source. Robotic cannulation of the left renal artery was achieved within 3 minutes. System setup time was 5 minutes. There were no postoperative complications. Computed tomography angiography performed at discharge and at 4-month follow-up confirmed target vessel patency with no evidence of an endoleak. Selective cannulation of target vessels during FEVAR using this novel technology is feasible. Endovascular robotics may have a role in simplifying complex endovascular tasks and potentially reducing radiation exposure to the operator.

  19. [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

  20. 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

  1. 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.

  2. 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

  3. 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

  4. David M. Hume Memorial Lecture. Impact of endovascular technology on the practice of vascular surgery.

    PubMed

    Veith, F J; Marin, M L

    1996-08-01

    Endovascular treatment techniques have already replaced some vascular operations. The likelihood is that new endovascular techniques involving stents and stented grafts will replace additional vascular operations. All these treatments involve the use of catheter-guidewire, balloon, and imaging modalities, particularly digital fluoroscopy. These modalities have already and will increasingly help to improve and simplify standard vascular operations such as thromboembolectomy, infrainguinal bypasses, and management of aneurysms and arteriovenous fistulas. Accordingly, vascular surgeons must become familiar with and use these endovascular methods and techniques. This can be accomplished in a variety of ways which includes working as part of a multidisciplinary vascular treatment group in which various specialists collaborate to provide the best, most cost-effective care to vascular disease patients.

  5. 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

  6. Results of Infrapopliteal Endovascular Procedures Performed in Diabetic Patients with Critical Limb Ischemia and Tissue Loss from the Perspective of an Angiosome-Oriented Revascularization Strategy

    PubMed Central

    Acín, Francisco; Varela, César; López de Maturana, Ignacio; de Haro, Joaquín; Bleda, Silvia; Rodriguez-Padilla, Javier

    2014-01-01

    Our aim was to describe our experience with infrapopliteal endovascular procedures performed in diabetic patients with ischemic ulcers and critical ischemia (CLI). A retrospective study of 101 procedures was performed. Our cohort was divided into groups according to the number of tibial vessels attempted and the number of patent tibial vessels achieved to the foot. An angiosome anatomical classification of ulcers were used to describe the local perfusion obtained after revascularization. Ischemic ulcer healing and limb salvage rates were measured. Ischemic ulcer healing at 12 months and limb salvage at 24 months was similar between a single revascularization and multiple revascularization attempts. The group in whom none patent tibial vessel to the foot was obtained presented lower healing and limb salvage rates. No differences were observed between obtaining a single patent tibial vessel versus more than one tibial vessel. Indirect revascularization of the ulcer through arterial-arterial connections provided similar results than those obtained after direct revascularization via its specific angiosome tibial artery. Our results suggest that, in CLI diabetic patients with ischemic ulcers that undergo infrapopliteal endovascular procedures, better results are expected if at least one patent vessel is obtained and flow is restored to the local ischemic area of the foot. PMID:24527215

  7. 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

  8. Endovascular therapy for overcoming challenges presented with blunt abdominal aortic injury.

    PubMed

    Gilani, Ramyar; Saucedo-Crespo, Hector; Scott, Bradford G; Tsai, Peter I; Wall, Metthew J; Mattox, Kenneth L

    2012-05-01

    Blunt abdominal aortic injury (BAAI) is a rare and lethal injury requiring surgical management. Injury patterns can be complex and surgical strategy should accommodate specific case circumstances. Endovascular solutions appear appropriate and preferred in certain cases of BAAI, which, however, may not be applicable due to device limitations in regard to patient anatomy and limited operating room capability. However, endovascular therapy can be pursued with limited fluoroscopy capability and consumable availability providing a solution that is expeditious and effective for select cases of BAAI.

  9. 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.

  10. 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

  11. 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

  12. 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

  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. Percutaneous Endovascular Recanalization of a Thrombosed Aortic Graft Limb with Stent Placement

    PubMed Central

    Georgakarakos, Efstratios; Kapoulas, Konstantinos

    2014-01-01

    Common practice in recanalization of a thrombosed prosthetic graft limb in an aortoiliac bypass focuses on balloon-catheter thrombectomy and angiographic exploration followed either by open surgical revision or endovascular management. This report describes the technique of percutaneous endovascular recanalization of an early thrombosed aortic graft limb with stent placement and subsequent restoration of patency and adequate limb perfusion, which remains patent after one year. Percutaneous intervention with stent placement and angioplasty for early graft limb recanalization avoids femoral incisions, and complications or morbidity associated with open surgery, while permitting rapid mobilization of the patient. PMID:26798727

  15. Percutaneous Endovascular Recanalization of a Thrombosed Aortic Graft Limb with Stent Placement.

    PubMed

    Georgakarakos, Efstratios; Kapoulas, Konstantinos

    2014-06-01

    Common practice in recanalization of a thrombosed prosthetic graft limb in an aortoiliac bypass focuses on balloon-catheter thrombectomy and angiographic exploration followed either by open surgical revision or endovascular management. This report describes the technique of percutaneous endovascular recanalization of an early thrombosed aortic graft limb with stent placement and subsequent restoration of patency and adequate limb perfusion, which remains patent after one year. Percutaneous intervention with stent placement and angioplasty for early graft limb recanalization avoids femoral incisions, and complications or morbidity associated with open surgery, while permitting rapid mobilization of the patient. PMID:26798727

  16. 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

  17. A Ruptured Basilar Tip Aneurysm Showing Repeated Perianeurysmal Edema after Endovascular Coil Embolization: Case Report

    PubMed Central

    TAKESHITA, Tomonori; HORIE, Nobutaka; FUKUDA, Yutaka; SO, Gohei; HAYASHI, Kentaro; MORIKAWA, Minoru; SUYAMA, Kazuhiko; NAGATA, Izumi

    The authors present an extremely rare case of a 48-year-old female who developed repeated perianeurysmal edema at 2, 9, and 16 weeks after endovascular coil embolization for the ruptured intracranial aneurysm. Interestingly, the mechanism for this edema could be different at each time point in this case; acute thrombosis formation, chemical inflammation, and aneurysm recanalization. We have to be aware of this potential complication in the long term after endovascular coil embolization for the intracranial aneurysm, especially with large size or buried into the brain parenchyma. The clinical implications of this case are discussed with a review of the literature. PMID:24390180

  18. Endovascular management of an acquired aortobronchial fistula following aortic bypass for coarctation.

    PubMed

    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.

  19. Endovascular Repair of a Ruptured Aortic Extra-anatomic Bypass Pseudoaneurysm After Previous Coarctation Surgery.

    PubMed

    Hörer, Tal; Toivola, Asko

    2015-01-01

    We present a short case of a total endovascular repair of a ruptured thoracic pseudoaneurysm after previous coarctation aortic conduit bypass surgery. A 67-year-old man with two previous coarctation repairs many years ago was admitted with chest pain, dyspnea, and hemoptysis. Computed tomography showed a rupture in the distal anastomosis of the thoracic extra-anatomic graft. Successful treatment was achieved by placement of an endovascular stent graft between the old graft and the native aorta and with a vascular plug occlusion of the native aorta.

  20. 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.