Aneurysm Stent Research Articles

Endovascular stenting for extracranial carotid artery aneurysms: Experiences and mid-term results.

The aim of this study was to investigate the safety and effectiveness of endovascular stenting for extracranial carotid artery aneurysms (ECAAs) and evaluate the mid-term outcomes.Twelve consecutive symptomatic patients (mean age 43.8 ± 14.9 years; 8 men) with ECAAs who were treated with endovascular stenting between 1997 and 2015 were retrospectively analyzed. Clinical follow-up data including symptoms and neurological events were obtained from outpatient records. Imaging follow-up with duplex ultrasound and/or computed tomographic angiography (CTA) was performed to examine the aneurysm obliteration and patency of the stents at 3, 6, 12 months and yearly thereafter.A total of 5 true aneurysms and 7 pseudoaneurysms were included in our series. Neurological symptoms (n = 5, 41.7%) and a pulsatile neck mass (n = 5, 41.7%) were the most common presenting symptoms. Endovascular stenting procedures were technically successful in all cases; 3 patients received bare stents, and 9 patients received covered stents. No perioperative neurologic or cardiopulmonary complications occurred. Over a period of follow-ups (mean 21.8 ± 25.1 months), all patients were alive and free from neurological or other adverse events. All aneurysms were completely excluded except for 1 patient who was exposed to a residual medium leaking into the aneurysm sac. No reintervention was performed in this specific patient because aneurysm growth or significant clinical symptoms did not occur. Recurrent restenosis assessed by CTA imaging at 12 months occurred in 1 (8.3%) patient in our series. Target lesion revascularization for this hemodynamic restenosis was treated with placement of an additional stent.In our series, endovascular stenting for ECAAs was found to be safe, effective, and proved to have promising mid-term results. Although long-term results need to be further explored, advantages including less procedure-related complications and a shorter recovery time make endovascular stenting an attractive option for ECAAs, especially for the patients who are unfit for traditional open surgery.

Altered renal functions in patients with occlusion of an accessory renal artery after endovascular stenting of an infrarenal aneurysm

ObjectiveCoverage of an accessory renal artery (ARA) during endovascular aneurysm repair (EVAR) may result in renal infarction (RI) or decline in renal function. Until now, it remains vague which patients are at risk to develop these complications. We therefore analyzed the effect of ARA sealing by EVAR with respect to the occurrence of RI and renal function. MethodsA retrospective analysis of the medical records and computed tomographic scans of patients who underwent EVAR within a period of 5 years was performed. Particular attention was paid to the presence or absence of accessory renal arteries and renal function before EVAR. Thirty-four patients with ARA were matched 1:3 to 102 patients without ARA. The results after EVAR were analyzed in patients with and without ARA. In patients with ARA, we further examined the results after EVAR in patients with an estimated glomerular filtration rate (eGFR) ≥ 60 mL/min and eGFR < 60 mL/min before EVAR. ResultsBefore EVAR, the median eGFR was 74 mL/min (25th/75th percentiles, 57/89) in patients with ARA and 72 mL/min (25th/75th percentiles, 63/87) in patients without ARA. Alterations in eGFR were significantly pronounced in patients with ARA when compared with patients without ARA 1 week after EVAR (ARA, −10.7 ± 16.9 mL/min vs without ARA, 1.2 ± 13.3 mL/min; P = .002) and after 6 months (ARA, −10.8 ± 17.4 mL/min vs without ARA, 1.2 ± 13.3 mL/min; P = .001). RI only occurred in patients with ARA. Within the group of patients with ARA, patients with normal renal function (NF) showed a more pronounced decline in eGFR preoperatively when compared with patients with impaired renal function (IF) 1 week after EVAR (NF, −14.3 ± 18.0 mL/min vs IF, −1.3 ± 10.8 mL/min; P = .02) and after 6 months (NF, −15.8 ± 17.9 mL/min vs IF, 0.1 ± 15.2 mL/min; P = .007). ConclusionsThe decrease in renal function was more pronounced in patients with ARA after EVAR when compared with patients without ARA undergoing EVAR. In patients with ARA, the observed decline in renal function was significantly distinct in patients presenting NF preoperatively. Consequently, the risk of IF after EVAR seems to be increased in patients with ARA and normal preoperative renal function.

The UK Pilot Study on Multi-layer Flow-Modulating Stents for Thoraco-Abdominal and Peri-renal Aneurysms: Results at Three Years

The UK Pilot Study on Multi-layer Flow-Modulating Stents for Thoraco-Abdominal and Peri-renal Aneurysms: Results at Three Years

Progressive coronary aneurysms in Behçet disease, a journey through surgical and percutaneous treatment: A case report

Behçet disease is a systemic autoimmune disease that causes inflammation within the vascular tree. Coronary arteries are rarely involved with stenosis, arteritis or aneurysm formation. Treatment is mainly directed to reduce the burden of inflammation systemically with steroid and immunosuppressive medications. However, patients might present in critical conditions requiring interventions in the form of percutaneous therapy or surgical bypass grafting. We present the case of a 34-year-old male who presented with acute coronary insult and was later found to have Behçet disease. His course was aggressive, as he required bypass graft surgery for rupture coronary aneurysm and cardiac tamponade. Later on, he required percutaneous intervention with cover stents for multiple coronary aneurysms that he developed afterward despite being on medical therapy.<Learning objective: Behçet disease is a rare cause of coronary aneurysms that present with acute coronary syndrome. The underlying etiology is related to inflammatory changes within the vessels. The main stay of treatment is medical therapy that suppresses the immune system. As these aneurysms are at risk of rupture, percutaneous interventions in the form of cover stents and bypass graft surgeries have been used with variable outcomes.>

A Rescue Technique for Intraoperative Proximal Migration of a Nellix Stent During Endovascular Aneurysm Sealing

Purpose: To describe a technique to rescue intraoperative migration of 1 of the 2 Nellix stents during endovascular sealing of abdominal aortic aneurysms (EVAS). Technique: The technique requires advancement and inflation of a 10-mm angioplasty balloon into the inlet of the migrated stent via an upper limb approach. Inflation of the balloon allows completion of EVAS without risking the contralateral endobag occluding the inlet of the migrated stent. Conclusion: This technique allows safe completion of EVAS without compromising stent patency or aneurysm seal and should be considered when intraoperative migration of a Nellix stent occurs despite appropriate precautions.

Rapid Virtual Stenting for Intracranial Aneurysms.

The rupture of Intracranial Aneurysms is the most severe form of stroke with high rates of mortality and disability. One of its primary treatments is to use stent or Flow Diverter to divert the blood flow away from the IA in a minimal invasive manner. To optimize such treatments, it is desirable to provide an automatic tool for virtual stenting before its actual implantation. In this paper, we propose a novel method, called ball-sweeping, for rapid virtual stenting. Our method sweeps a maximum inscribed sphere through the aneurysmal region of the vessel and directly generates a stent surface touching the vessel wall without needing to iteratively grow a deformable stent surface. Our resulting stent mesh has guaranteed smoothness and variable pore density to achieve an enhanced occlusion performance. Comparing to existing methods, our technique is computationally much more efficient.

Endovascular aortic aneurysm repair: a method of treatment of abdominal aortic aneurysm stent implantation.

2016;11(3-4):130. VII. nacionalni sastanak o kardiovaskularnim intervencijama s međunarodnim sudjelovanjem VI. sastanak intervencijskih kardioloskih medicinskih sestara i tehnicara Abdominal aortic aneurysm, along with myocardial infarction and stroke is one of the most common diseases of blood vessels, and it is estimated that almost 10% of the male population over age 60 has an aneurysm. The mortality of ruptured abdominal aortic aneurysm in some cases is growing to an alarming 90%. With the former techniques of treating aneurysms, such as conservative (drug therapy) treatment and open surgery, in 1991 the endovascular aortic repair was introduced as a significantly less invasive method than surgery.

Willis covered stent for complex internal carotid aneurysms

Objective To investigate the safety and efficacy of the Willis covered stent system for the treatment of complex internal carotid aneurysms. Methods Eight patients with complex internal carotid aneurysm treated with Willis covered stent system at the Department of Neurosurgery, Nanfang Hospital, Southern Medical University from November 2013 to May 2015 were analyzed retrospectively. Among them, 3 patients had internal carotid artery blood blister like aneurysms, 2 had paraclinoid segment aneurysms, and 3 had cavernous segment aneurysms (1 traumatic pseudoaneurysm, 1 iatrogenic pseudoaneurysm, and 1 giant aneurysm). According to the intraoperative condition of the paren artery, the guiding catheters were placed as high as possible (near the cavernous segment) to provide adequate support. After the covered stents were implanted.the balloon were inflated to release the stent and the aneurysm were eliminated at the same time. Results Eight patients with complex internal carotid aneurysm (8 aneurysms) were implanted 8 covered stents, 7 of them were successfully released in the parent arteries. Angiography immediately after stenting in 5 patients showed that the lesions disappeared completely and the parent arteries were patent; After 1 stent was implanted, 1 patient with recurrent giant aneurysm at the cavernous segment after stent-assisted embolization, a small amount of contrast agent leaked into the aneurysm (endoleak). The stent system in place was difficult in 1 patent with blood blister like aneurysm because of his internal carotid artery tortuosity. Iatrogenic internal carotid cavernous fistula occurred during the operation. Bypass and occlusion of the parent artery was performed after balloon embolization. Other cases did not have operation-related complications. The 8 patients were followed up clinically at 2 to 12 months after procedure. They did not have any neurological deficits. The modified Rankin scale (mRS) scores were 0 in 5 cases, 1 in 2 cases, and 2 in 1 case. Three patients got DSA followed-up again at 6 month after procedure. No recurrence of aneurysms was observed, and their parent arteries were patent without stenosis. Conclusion Willis covered stents were safe and effective for the treatment of some complex internal carotid artery aneurysms. Key words: Intracranial aneurysm; Carotid artery, internal; Willis covered stents

Dose reduction in cone-beam CT scanning for intracranial stent deployment before coil embolization of intracranial wide-neck aneurysms.

Flat panel detector (FD)-equipped angiography machines are increasingly used for neuro-angiographic imaging. During intracranial stent-assisted coil embolization procedures, it is very important to clearly and quickly visualize stent shape after deployment in the vessel. It is necessary to quickly visualize stents by cone-beam computed tomography (CBCT). The aim of this study was to compare CBCTs at 10 and 20 s, and to confirm that this method is useful for neuro-endovascular treatment procedures. We treated 30 patients with wide-necked intracranial aneurysms with a flexible, self-expanding neurovascular stent and subsequent aneurysm embolization with platinum micro-coils. We performed the CBCT after stent deployment. We compared the 10 s and 20 s CBCTs, using the full width one-half maximum (FWHM) visualization. Accurate stent placement with subsequent coil occlusion of the aneurysms was feasible in all patients. Stent struts were clearly visualized on both 10 s and 20 s CBCTs. Importantly, 10 s CBCT can reduce the radiation dose by about 42%, compared with 20 s CBCT. Performing 10 s CBCT with a 14% dilution of the contrast medium may significantly improve image acquisition during stent-assisted coil embolization. Reduced-dose, 10 s CBCT can visualize stents in clinical cases, while significantly reducing radiation exposure.

Virtual stenting workflow with vessel-specific initialization and adaptive expansion for neurovascular stents and flow diverters

Endovascular intervention using traditional neurovascular stents and densely braided flow diverters (FDs) have become the preferred treatment strategies for traditionally challenging intracranial aneurysms. Modeling stent and FD deployment in patient-specific aneurysms and its flow modification results prior to the actual intervention can potentially predict the patient outcome and treatment optimization. We present a clinically focused, streamlined virtual stenting workflow that efficiently simulates stent and FD treatment in patient-specific aneurysms based on expanding a simplex mesh structure. The simplex mesh is generated using an innovative vessel-specific initialization technique, which uses the patient’s parent artery diameter to identify the initial position of the simplex mesh inside the artery. A novel adaptive expansion algorithm enables the acceleration of deployment process by adjusting the expansion forces based on the distance of the simplex mesh from the parent vessel. The virtual stenting workflow was tested by modeling the treatment of two patient-specific aneurysms using the Enterprise stent and the Pipeline Embolization Device (commercial FD). Both devices were deployed in the aneurysm models in a few seconds. Computational fluid dynamics analyses of pre- and post-treatment aneurysmal hemodynamics show flow reduction in the aneurysmal sac in treated aneurysms, with the FD diverting more flow than the Enterprise stent. The test results show that this workflow can rapidly simulate clinical deployment of stents and FDs, hence paving the way for its future clinical implementation.

Computational fluid dynamics analysis of flow reduction induced by flow-diverting stents in intracranial aneurysms: a patient-unspecific hemodynamics change perspective

Background and purposeFlow-diverter stents (FDSs) have been used effectively to treat large neck and complex saccular aneurysms on the anterior carotid circulation. Intra-aneurysmal flow reduction induces progressive aneurysm thrombosis in...

Flow-diverter devices in the treatment of intracranial aneurysms: A meta-analysis and systematic review.

The purpose of this report was to discuss the overall limitations, safety and efficacy of flow-diverter stenting for intracranial aneurysms. The authors performed a meta-analysis from January 2009 to September 2014 using the terms "flow diverter" and "intracranial aneurysms." Additional studies were identified through references in each reviewed article. Data extraction, performed independently by the authors, included demographic data, technical and clinical complications, morbidity and mortality, aneurismal occlusion rates related to flow-diverter devices. The analysis was performed using a fixed effect. Twenty-nine studies with 1524 patients and three to 62 months of follow-up were identified for analysis. The overall technical failure and complication rate was 9.3% (95% CI 6%-12.6%). The rate of procedure-related complication was 14% (95% CI 10.2%-17.9%) and 6.6% (95% CI 4%-9.1%) for morbidity and mortality. Fusiform, dissecting and circumferential aneurysm (OR 3.10, 95% CI 0.93-10.37) were significant risk factors for technical failure and complication. Posterior circulation location (OR 4.03, 95% CI 2.45-6.61), peripheral location (OR 2.74, 95% CI 1.52-4.94) and fusiform, dissecting and circumferential aneurysm (OR 1.95, 95% CI 1.15-3.30) were statistically significant risk factors for procedure-related complications. Posterior circulation location (OR 4.39, 95% CI 2.44-7.90) and peripheral location (OR 3.64, 95% CI 1.74-7.62) were statistically significant risk factors for morbidity and mortality. Fusiform, dissecting and circumferential aneurysm, posterior circulation and peripheral locations have greater procedure-related complications.

234 内頸動脈瘤に対するステントメッシュ形状の最適設計(GS2-4 流体の数値計算)

234 内頸動脈瘤に対するステントメッシュ形状の最適設計(GS2-4 流体の数値計算)

Y-configuration Stent-assisted Coil Embolization for Wide-necked Intracranial Bifurcation Aneurysms.

ObjectiveThe objective of this study was to determine the efficiency and safety of Y configuration stent-assisted coiling with double-closed stents for wide-necked intracranial aneurysms located at arterial bifurcations thorough analysis of a multicenter case series.Materials and MethodsA retrospective chart review was done on 10 patients who underwent endovascular treatment of wide-necked intracranial aneurysms with Y-configuration stent-assisted coil embolization in three centers from August 2011 to March 2014. The degree of aneurysmal occlusion was assessed using the Raymond scale. Clinical outcomes were assessed before operation, at discharge, and at the last follow-up visit using the Glasgow outcome scale.ResultsThe 10 patients included 6 females and 4 males with a mean age of 58.6 years. Indications for treatment included 6 unruptured intracranial aneurysms and 4 ruptured intracranial aneurysms. Five aneurysms were located at the basilar artery bifurcation, four aneurysms were located in an anterior communicating artery, and one aneurysm was in the pericallosal artery. The mean size of the 10 aneurysms was 9.7 mm. All aneurysms had a dome-to-neck ratio of < 1.5 (mean, 0.89). Immediate complications included one thromboembolic event out of the 10 cases. Immediate posttreatment angiograms showed complete occlusion in 1 aneurysm and residual necks in 9 aneurysms. Follow-up results showed 8 complete occlusions and 2 residual necks. No delayed complications were observed during the follow-up period (mean: 20 months).ConclusionY configuration using double-closed cell stents is feasible and safe in selected patients. This method is an acceptable option for managing complex wide-necked bifurcations.

Endovascular stenting of traumatic extracranial internal carotid artery aneurysm in a pediatric patient

Endovascular stenting of traumatic extracranial internal carotid artery aneurysm in a pediatric patient

How to manage a case of aymptomatic thoraco-abdominal aortic aneurysm with occluded mesenteric arteries

We report a unique case of a 57-year-old male having a suprarenal thoraco-abdominal aortic aneurysm which is extending till the origin of superior mesenteric artery (SMA). The origins of celiac artery and SMA were totally occluded and filled retrogradely through dense collateral vessels arising from the inferior mesenteric artery. Surprisingly, the patient was not having any symptoms related to mesenteric ischemia. We decided to use a conventional aortic aneurysm stent graft to repair it without revascularizing the occluded mesenteric arteries. After 1 month, CT aortogram was repeated which revealed a well-apposed stent graft with no endoleaks. He did not have any clinical signs and symptoms attributable to mesenteric ischemia.

Abstract 11722: Excellent Preclinical Results of Honeycomb Microporous Covered Stents for the Treatment of Large and Wide-Necked Cerebral Aneurysms

Background: We developed covered stents with a microhoneycomb mesh for the treatment of large or giant wide-necked cerebral aneurysms. These aneurysms are extremely difficult to treat and carry high risks, even with the use of clinically available surgical methods or the endovascular technique using coils with the assistance of bare stents. This preclinical study confirmed the excellent performance of our stents in three animal experimental models. Methods and Results: The covered stents were prepared by using balloon-expandable stents (CoCr; diameter, 3.5-5.0 mm; length, 16-28 mm) and by dip coating to cover their struts completely with a polyurethane membrane (thickness, 20 μm), followed by laser microprocessing (pore size, approximately 100 μm; opening ratio, approximately 30%). Model 1: In prepared tortuous canine arteries (n = 12) that simulated the shape of the human internal carotid artery, all stent-mounted delivery catheters could smoothly navigate with little arterial damage. Model 2: In a prepared canine model (n = 10) of large (over 7 mm), wide-necked (over 4 mm) outer-sidewall aneurysms, at 3 months after stenting, completely endothelialized neointima was formed at the aneurysm openings and the aneurysm sacs were entirely organized. Model 3: In rabbit branching abdominal aortas, the vascular flow pattern at all the branching arteries remained unchanged for over 1 year, even after performing overlap stenting (n = 5) in addition to single stenting (n = 5). On all the stented luminal surfaces, complete thin neointimal formation with complete endothelialization was observed. Conclusion: Our newly developed novel covered stents exhibited excellent preclinical performance in three animal experimental models in terms of stent delivery, aneurysm embolization, and flow maintenance in branching arteries. We highly expect that the stents will be useful as endovascular embolization devices for large and wide-necked aneurysms in humans.

Virtual stenting of intracranial aneurysms: application of hemodynamic modification analysis.

Practical application of hemodynamic modification analysis based on computational fluid dynamics (CFD) in intracranial aneurysms is still under study. To determine the clinical applicability of virtual stenting of aneurysms by comparing the simulated results with clinical outcome of real stenting. Three-dimensional (3D) digital subtraction angiography (DSA) images were imported to a dedicated integrated prototypic CFD platform (Siemens Healthcare GmbH) which allows all necessary steps of 3D models for CFD analysis. The results of CFD simulation with virtual implantation of a stent can be visualized in the same platform for qualitative comparisons on a color-coded volume visualization window. Five small intracranial aneurysms with and without virtual stenting were analyzed and assessed on a qualitative level. Expert rating were performed for evaluating the simulated results, and comparing those to the long-term follow-up outcomes of real stenting. CFD simulation after virtual stenting was feasible in five differently located aneurysms and corresponded to the long-term changes of stented aneurysms by showing alteration in flow pattern. There was no significant difference (P = 0.5) between the simulated hemodynamic changes after virtual stenting and the angiographic changes after stenting in four aneurysms except one. There was good agreement regarding the assessment of the changes by two raters (kappa = 0.657). CFD analysis using patient-specific virtual stenting of the CFD platform may be used as a simple and less time-consuming test tool predicting the involution of aneurysms after stent placement by analyzing the vector visualization of the flow changes.

An Experimental Set-Up for Navigated-Contrast-Agent and Radiation Sparing Endovascular Aortic Repair (Nav-CARS EVAR)

Over the last decade endovascular stenting of aortic aneurysm (EVAR) has been developed from single centre experiences to a standard procedure. With increasing clinical expertise and medical technology advances treatment of even complex aneurysms are feasible by endovascular methods. One integral part for the success of this minimally invasive procedure is innovative and improved vascular imaging to generate exact measurements and correct placement of stent prosthesis. One of the greatest difficulty in learning and performing this endovascular therapy is the fact that the three-dimensional vascular tree has to be overlaid with the two-dimensional angiographic scene by the vascular surgeon. We report the development of real-time navigation software, which allows a three-dimensional endoluminal view of the vascular system during an EVAR procedure in patients with infrarenal aortic aneurysm. We used the preoperative planning CT angiography for three-dimensional reconstruction of aortic anatomy by volume-rendered segmentation. At the beginning of the intervention the relevant landmarks are matched in real-time with the two-dimensional angiographic scene. During the intervention the software continously registers the position of the guide-wire or the stent. An additional 3D-screen shows the generated endoluminal view during the whole intervention in real-time. We examined the combination of hardware and software components including complex image registration and fibre optic sensor technology (fibre-bragg navigation) with integration in stent graft introducer sheaths using patient-specific vascular phantoms in an experimental setting. From a technical point of view the feasibility of fibre-Bragg navigation has been proven in our experimental setting with patient-based vascular models. Three-dimensional preoperative planning including registration and simulation of virtual angioscopy in real time are realised. The aim of the Nav-CARS-EVAR concept is reduction of contrast medium and radiation dose by a three-dimensional navigation during the EVAR procedure. To implement fibre-Bragg navigation further experimental studies are necessary to verify accuracy before clinical application.

An automatic CFD-based flow diverter optimization principle for patient-specific intracranial aneurysms

The optimal treatment of intracranial aneurysms using flow diverting devices is a fundamental issue for neuroradiologists as well as neurosurgeons. Due to highly irregular manifold aneurysm shapes and locations, the choice of the stent and the patient-specific deployment strategy can be a very difficult decision.To support the therapy planning, a new method is introduced that combines a three-dimensional CFD-based optimization with a realistic deployment of a virtual flow diverting stent for a given aneurysm. To demonstrate the feasibility of this method, it was applied to a patient-specific intracranial giant aneurysm that was successfully treated using a commercial flow diverter. Eight treatment scenarios with different local compressions were considered in a fully automated simulation loop. The impact on the corresponding blood flow behavior was evaluated qualitatively as well as quantitatively, and the optimal configuration for this specific case was identified.The virtual deployment of an uncompressed flow diverter reduced the inflow into the aneurysm by 24.4% compared to the untreated case. Depending on the positioning of the local stent compression below the ostium, blood flow reduction could vary between 27.3% and 33.4%. Therefore, a broad range of potential treatment outcomes was identified, illustrating the variability of a given flow diverter deployment in general.This method represents a proof of concept to automatically identify the optimal treatment for a patient in a virtual study under certain assumptions. Hence, it contributes to the improvement of virtual stenting for intracranial aneurysms and can support physicians during therapy planning in the future.