Aneurysm Stent Research Articles

PS218. Plasma and Patterning: The New Focus for the Development of Nanocomposite Vascular Grafts

Introduction: Over the last decade, interventional endovascular stenting of aortic aneurysm has been developed from single center experiences to a standard procedure in many countries. One integral part for the success of this minimally-invasive procedure is innovative and improved vascular imaging. One of the most difficulty in learning and performing this interventional therapy is the fact, that the three-dimensional vascular tree has to be overlain with the two-dimensional angiographic scene by the vascular surgeon. Methods: We report the development of real-time navigation software, which allows a three-dimensional endoluminal view of the vascular system during an EVARprocedure in patients with infrarenal aortic aneurysm. Even in patients with complex anatomy, the surgeon or the interventionalist achieves an accurate option of spatial perception concerning the current vascular anatomy, e.g. the position of the guide-wire. We analyzed patients with an infra-renal aortic aneurysm in which the planning CT-Scans were volumerendered. At the beginning of the intervention the relevant landmarks were matched in real-time with the twodimensional angiographic scene. During intervention the software continuously registers the position of the guidewire or the stent. An additional 3d-screen shows the generated endoluminal view during the whole intervention in real-time. Results: Our preliminary results of navigated endoluminal virtual angioscopy are promising. The “Virtual angioscope” may improve intraoperative visualization, placement of guide-wires and stents. It may reduce the amount of contrast agents and exposure to x-Rays. The prototype also offers the possibility of intervention planning and simulation which may lead to a reduced learning curve and therefore patient safety. Conclusion: Not only for pre-interventional simulation, even in training of inexperienced surgeons or interventionalists, our 3D navigation system may offer better visualization in complex endoluminal aortic procedures. Plasma and Patterning: The New Focus for the Development of Nanocomposite Vascular Grafts

Prototype of a 3D-navigation System for Interventional Therapy of Aortic Aneurysms

Introduction: Over the last decade, interventional endovascular stenting of aortic aneurysm has been developed from single center experiences to a standard procedure in many countries. One integral part for the success of this minimally-invasive procedure is innovative and improved vascular imaging. One of the most difficulty in learning and performing this interventional therapy is the fact, that the three-dimensional vascular tree has to be overlain with the two-dimensional angiographic scene by the vascular surgeon. Methods: We report the development of real-time navigation software, which allows a three-dimensional endoluminal view of the vascular system during an EVARprocedure in patients with infrarenal aortic aneurysm. Even in patients with complex anatomy, the surgeon or the interventionalist achieves an accurate option of spatial perception concerning the current vascular anatomy, e.g. the position of the guide-wire. We analyzed patients with an infra-renal aortic aneurysm in which the planning CT-Scans were volumerendered. At the beginning of the intervention the relevant landmarks were matched in real-time with the twodimensional angiographic scene. During intervention the software continuously registers the position of the guidewire or the stent. An additional 3d-screen shows the generated endoluminal view during the whole intervention in real-time. Results: Our preliminary results of navigated endoluminal virtual angioscopy are promising. The “Virtual angioscope” may improve intraoperative visualization, placement of guide-wires and stents. It may reduce the amount of contrast agents and exposure to x-Rays. The prototype also offers the possibility of intervention planning and simulation which may lead to a reduced learning curve and therefore patient safety. Conclusion: Not only for pre-interventional simulation, even in training of inexperienced surgeons or interventionalists, our 3D navigation system may offer better visualization in complex endoluminal aortic procedures. Plasma and Patterning: The New Focus for the Development of Nanocomposite Vascular Grafts

Overlapping stents for blood blister-like aneurysms of the internal carotid artery

ObjectiveBlood blister-like aneurysms (BBAs) are unique due to their high risk of recurrent bleeding associated with their fragile neck. The best treatment for BBAs is still controversial. This paper sought to evaluate the safety and efficacy of stent-assisted coiling and subsequent overlapping stents (SAC+OS) in the treatment of BBAs. MethodsFifteen consecutive patients with ruptured BBAs managed with SAC+OS were enrolled in this study. The clinical characteristics, procedural data, angiographic outcome, and follow-up results were reviewed. ResultsSAC+OS were successfully performed in all 15 cases. The instant angiographic result was total occlusion in 6 cases, residual neck in 7 cases, and residual aneurysm in 2 cases. Angiographic follow-ups revealed total occlusion in all 6 cases treated by triple or quadruple stents, and 6 of 9 cases treated by double stents. Major recanalization was detected in 3 cases treated by double stents. The modified Rankin Scale score at 4–52 months follow-up (23.8 months on average) was 0 in 6 cases, 1 in 8 cases, and 3 in one case. ConclusionStent-assisted coiling and subsequent overlapping stents are feasible and safe for BBAs. It can be helpful to further decrease the risk of recanalization with more stents. Early angiographic follow-up within 2 weeks is recommended.

Use of pipeline flow diverting stents for wide neck intracranial aneurysms: A retrospective institutional review.

Background:Intracranial aneurysms (ICA) if inadequately treated may result in serious morbidity and mortality. Wide-neck; large/giant, fusiform, and dissecting aneurysms are not well treated using the conventional coil embolization technique. Recent advance in endovascular treatment and technology has introduced flow diverter devices including pipeline embolization devices (PED) and Silk stents that have been shown to be more effective in treating these more complicated aneurysms. Flow Diverter devices offer a more physiologic approach to ICA treatment.Methods:We conducted a retrospective chart review of 23 adult patients who underwent aneurysm treatment utilizing the pipeline stent at Duke University Medical Center from July 2011 to March 2013.Results:Majority of patients (19, 82.7%) showed angiographic evidence of complete obliteration of aneurysm at 6 months follow-up, with sustained clinical improvement on modified Rankin scale score. All of the patients tolerated the procedure well with no intra-operative hemorrhage or intra-operative thromboembolic complications.Conclusions:Our experience shows that use of PED offers a safe and effective strategy for treatment of complex ICA. Larger prospective studies are needed to confirm these observations.

Optical Coherence Tomography Appearances in Healed Coronary Artery Aneurysms After Stent Implantation

We earlier reported late stent malapposition and marked coronary artery aneurysm (CAN) formation at the site of implantation of 2 bare-metal stents (BMS), Multilink Vision (Abbott Laboratories, Abbott Park, Illinois) and Liberte (Boston Scientific Corporation, Natick, Massachusetts), to the proximal

Unknown pages in the history of vascular stent grafting

Unknown pages in the history of vascular stent grafting

Safety and performance of the Penumbra Liberty stent system in a rabbit aneurysm model

BackgroundEndovascular treatment of wide necked and large/giant intracranial aneurysms is challenging. The goal of this study was to evaluate the Liberty stent system in the rabbit elastase aneurysm model for...

Evolving role of endovascular treatment for MCA bifurcation aneurysms: case series of 184 aneurysms and review of the literature

Objective: This study evaluates the role of endovascular therapy for middle cerebral artery (MCA) aneurysms and its evolution over time. We are reporting a large case series of 184 MCA aneurysms and comparative analysis of the literature.Methods: This was a retrospective review of a prospectively maintained database including all patients with MCA bifurcation aneurysms embolized between 2000 and 2013. There were 184 aneurysms in 166 patients, with 71 ruptured and 113 nonruptured aneurysms.Results: Stent assistance was required in 70 cases (38·0%) and 3 cases (1·6%) required ‘Y’ stenting. The initial rate of total aneurysm occlusion was 59·8% and at delayed follow up was 90·1%. Seven embolizations resulted in thrombo-embolic complications (3·8%), with no cases of aneurysm re-bleeding, wire perforations, or other hemorrhages. Three patients with ruptured aneurysms died of causes unrelated to the embolization, and none with nonruptured aneurysms died in the follow-up period (total mortality 1·6% at 30 days post-procedure). A total of seven aneurysms (3·9%) required retreatment with an average follow up of 41 months. Prior to dedicated aneurysm stents, 68·8% of patients underwent embolization with the remainder surgically treated. Following the introduction of aneurysm stents in 2002, 92·0% of MCA aneurysms treated were embolized.Conclusions: During the past decade we have seen a treatment paradigm shift in MCA aneurysm treatment from surgical treatment to endovascular treatment. Developments in 3D angiography, more compliant balloons, dedicated aneurysm stents, complex coils, and antiplatelet therapy regimes have led to this transition for safe and effective management of these patients.

Three-dimensional hemodynamic design optimization of stents for cerebral aneurysms

Flow-diverting stents occlude aneurysms by diverting the blood flow from entering the aneurysm sac. Their effectiveness is determined by the thrombus formation rate, which depends greatly on stent design. The aim of this study was to provide a general framework for efficient stent design using design optimization methods, with a focus on stent hemodynamics as the starting point. Kriging method was used for completing design optimization. Three different cases of idealized stents were considered, and 40-60 samples from each case were evaluated using computational fluid dynamics. Using maximum velocity and vorticity reduction as objective functions, the optimized designs were identified from the samples. A number of optimized stent designs have been found from optimization, which revealed that a combination of high pore density and thin struts is desired. Additionally, distributing struts near the proximal end of aneurysm neck was found to be effective. The success of the methods and framework devised in this study offers a future possibility of incorporating other disciplines to carry out multidisciplinary design optimization.

726 ステントを用いた脳動脈瘤治療における血流阻害効果の数値解析(GS-2 呼吸・循環)

726 ステントを用いた脳動脈瘤治療における血流阻害効果の数値解析(GS-2 呼吸・循環)

A case of stent aneurysm following everolimus eluting stent implantation

Coronary artery aneurysm commonly occurs secondary to atherosclerosis,but aneurysm formation after stenting is a rare phenomenon specially after drug eluting stent implantation. Drug-eluting stents (DES) elute antiproliferative drugs, can inhibit neointimal growth and may delay healing after vascular injury, and DES implantation may be associated with a risk of coronary artery aneurysm formation. Coronary aneurysms have been reported from 3 days to up to 4 years after DES implantation procedures, with varying clinical presentations. Incidence of coronary artery aneurysms after DES implantation is low within the first 9 months, with a reported incidence of 0.2% to 2.3%, a rate similar to that reported after bare-metal stent (BMS) implantation (0.3% to 3.9%). In our case,the patient is a nondiabetic ,nonhypertensive 68 year old male who underwent coronary angioplasty in the RCA with everolimus eluting stent following acute coronary syndrome.After few weeks the patient came with exertional angina and coronary angiography revealed stent aneurysm formation with new disease proximal to the stent.

Clinical experience with multiple stents in complex thoracoabdominal aortic aneurysms

Clinical experience with multiple stents in complex thoracoabdominal aortic aneurysms

Use of Flow-Diverting Stents to Treat Para-Anastomotic Iliac Artery Aneurysms After Previous Open Aortic Prosthetic Reconstruction

To present a series of para-anastomotic iliac artery aneurysms treated with flow-diverting stents. Three patients (2 men, 1 woman; ages 70, 73, and 78 years) with previous open aortoiliac reconstructions received a 12-mm-diameter Cardiatis Multilayer Stent to treat 4 para-anastomotic iliac artery aneurysms in an attempt to preserve their ipsilateral hypogastric arteries. After 1-year follow-up, all aneurysms were successfully excluded, with complete sac thrombosis in three and partial thrombosis in one. The diameter of the aneurysm was reduced in all by a median 6 mm. At 1 year, patency of the hypogastric artery was maintained in only the patient with partial sac thrombosis. No patient developed buttock claudication. The use of flow-diverting stents for para-anastomotic iliac artery aneurysms resulted in reduction of iliac aneurysm diameter. However, intended patency of the ipsilateral hypogastric artery was not always observed. The feasibility of the technique has therefore not been shown for this specific indication.

Role of Multidetector CT in Assessment of Repaired Tetralogy of Fallot

The population of adults with repaired tetralogy of Fallot (TOF) is growing, thanks to improvements in the surgical and medical management of this condition. Accordingly, late postrepair complications are important medical concerns in these individuals. Initial surgical repair of TOF typically occurs in infancy, consisting of patch repair of the ventricular septal defect (VSD) and relief of right ventricular outflow tract (RVOT) obstruction. Although patients may remain asymptomatic for several decades, the majority will have progressive pulmonic regurgitation that leads to right ventricular (RV) dilatation and functional deterioration. Other frequently seen complications include branch pulmonary artery stenosis, RVOT aneurysms, and recurrent VSDs. Cardiac computed tomography (CT) is widely available and, in some cases, is the imaging modality of choice for serial evaluation of TOF patients. CT is particularly useful when magnetic resonance (MR) imaging is contraindicated (eg, in patients with implantable cardiac devices). Unlike MR imaging, cardiac CT allows excellent visualization of endovascular stents and stent-mounted valves. Retrospective electrocardiographically gated cardiac CT can be used for accurate volumetric and functional analysis of the RV. Comprehensive serial evaluation will assist in determining the need for surgical pulmonary valve repair in the setting of progressive RV dysfunction. Three-dimensional volumetric images are useful for evaluation of stent integrity and aneurysm formation. The radiologist should be familiar with the anatomy of TOF, surgical interventions for repair, and postrepair complications encountered at follow-up imaging of these patients. By extracting the breadth of information obtained with cardiac multidetector CT, the radiologist can play an essential role in the management of adult patients with repaired TOF.

Neuroform Intracranial Stenting for Aneurysms Using Simple and Multi-stent Technique Is Associated With Low Risk of Magnetic Resonance Diffusion-Weighted Imaging Lesions

Detection of procedural thromboembolism by diffusion-weighted magnetic resonance imaging (MR-DWI+) can help identify and mitigate endovascular risk factors. Data remain scant on procedural MR-DWI+ following the use of the Neuroform open-cell design stent in aneurysm embolization. We sought to evaluate the incidence of MR-DWI+ in Neuroform simple and multi-stent construct stenting for intracranial aneurysms in an attempt to delineate baseline risk and identify possible associated procedural factors. Seventy-six patients receiving 97 Neuroform stents in the treatment of intracranial aneurysm were identified from a prospective database and eligible for inclusion in the study. Diffusion-weighted magnetic resonance imaging (MR-DWI) was obtained in all patients within 48 hours of the procedure and reviewed for the presence of MR-DWI+ with patient records reviewed for analysis of factors predisposing to these lesions. Patients were treated with single-stent Neuroform constructs in 57 cases (73%) and multi-stent Neuroform constructs in 21 cases (27%). Y-stent technique was used in 16 cases. MR-DWI+ was identified in 7 of 78 cases (9.0%), with MR-DWI+ in 0 of 10 subarachnoid hemorrhage cases. No MR-DWI lesions led to a permanent neurological deficit at discharge. There was no MR-DWI+ in patients treated with Y-stenting or multi-stent Neuroform constructs. The only factor associated with ipsilateral MR-DWI+ was target aneurysm location on an arterial sidewall over bifurcation (P = .01). The Neuroform stent carries a very low risk of MR-DWI+ compared with its closed-cell design counterpart. Subarachnoid hemorrhage and deployment of multiple stents in the same anatomical region in configurations such as the Y-stent construct did not increase the risk of acute procedural thromboembolism.

The Safety and Efficacy of Stenting in the Treatment of Complex Posterior Cerebral Artery Aneurysms: A Seven-Case Report and Literature Review

To investigate the safety and efficacy of stenting with coil in the endovascular treatment of complex posterior cerebral artery (PCA) aneurysms. The data on PCA aneurysms treated with stents were retrospectively reviewed from a prospectively collected intervention database. The literature was reviewed concerning the use of stents for PCA aneurysms. Seven cases with complex PCA aneurysms (male: female = 6:1; ruptured: unruptured = 4:3) were retrieved from our database. Three aneurysms were localized at the junction of P1 and P2 segments (P1-2), two at P1, and two at P2A. Four were wide-necked saccular aneurysms, while the other three were dissecting ones. A total of nine stents (one Neuroform and eight Enterprise stents) were successfully deployed. Two aneurysms were totally eliminated, three were with neck residues and two were partially occluded. No procedure-related complications occurred. All patients recovered well. Angiographic follow-ups (FU) showed that three aneurysms achieved total obliterations, one got improved, two remained stable, and one recurred. The recurred aneurysm caused no symptom and was treated with two stents. Clinical FU demonstrated no neurological deterioration or bleeding. In literature review, the procedure-related mortality is 5.3 % (2/38). The incidence of permanent neurologic deficit is 2.6 % (1/38). Three (3/23) aneurysms recurred, of which one caused rebleeding. Four (4/23) in-stent stenoses were all asymptomatic. No other hemorrhagic or ischemic event occurred in clinical FU. Stent offers a therapeutic alternative for complex PCA aneurysms especially when PVO cannot be tolerated. Long-term therapeutic efficacy requires further observations in clinical series with larger case numbers.

Successful management of a proximally migrated stent in a middle-aged woman with unnoticed native aortic coarctation

Endovascular stent placement for adults with a newly diagnosed native discrete post-subclavian aortic coarctation (AC) became widely acceptedas an alternative to surgery,despite thatthe efficacyand long term safety of the technique have not yet been well established [1]. Placement of stent can be technically challenging and has been associated with serious complications, such as acute aortic rupture (rare), aortic dissection, femoral artery trauma, subacute stent thrombosis, recurrent coarctation, and aneurysm formation [2]. There is a paucity of data regarding stent migration, its causes; and its management has not been well defined. Proximal migration of a (covered) stent is a very rare occurrence [3]. To our knowledge, no previous reports of a proximally migrated covered stent and its successful repositioning using a peripheral balloon catheter during transcatheter management of AC in an adult have been published. We report a woman with a native AC whose treatment was complicated by stent migration proximally, which was then successfully repositioned at the expected site by transcatheter technique. A 45-year-old woman was referred for catheterization after her diagnostic work-up for resistant hypertension suggested renal artery stenosis. Her past medical history was notable for a 10-year history of hypertension. She had no other history of cardiovascular disease. She had hadtwo prior pregnancies,with ahistoryof hypertension requiring no drug therapy. Her medical regimen included nebivolol, lercanidipine, irbesartan, hydrochlorothiazide, and atorvastatin at the time of presentation. A thorough physical examination was performed, revealing the blood pressure difference between the right arm and leg of 30 mm Hg in the presence of systemic hypertension, a radial–femoral pulse delay with weak lower limb pulses, and faint mid-systolic murmur over the chest and back. Her electrocardiogram was normal with no evidence of left ventricular hypertrophy or ischemia. Echocardiography demonstrated left atrial dilatation, moderate mitral regurgitation, with an estimated left ventricular ejection fraction of 65%. However, gradient measurement by continuous wave Doppler was not obtainable. No other associated abnormalities were detected.

Distant and Delayed (>7 Days) Hemorrhage after Treatment by Flow-Diverter Stents in Intracranial Aneurysms: A Rare but Potentially Serious Complication

In a recent meta-analysis, intraparenchymal hemorrhage secondary to treatment by a flow-diverter stent (FDS) was reported in 3% of the cases.[1][1] Most of these hemorrhages were periprocedural complications. More surprising cases of delayed ipsilateral hemorrhage have been reported lately in

Toward smart utilization of two X-ray images for 2-D/3-D registration applied to abdominal aortic aneurysm interventions

Minimally invasive abdominal aortic aneurysm stenting can be greatly facilitated by overlaying the pre-operative 3-D model of the abdominal aorta onto the intra-operative 2-D X-ray images. Accurate 2-D/3-D registration in 3-D space makes the 2-D/3-D overlay robust to the change of C-Arm angulations. Typically at least two X-ray images showing the abdominal aorta with contrast medium from different angles are needed for an accurate registration in 3-D space. In this paper, a novel 2-D/3-D registration technique is proposed for using only one image with contrast medium in the abdominal aorta and one native image showing the spine to achieve accurate registration of the abdominal aorta in 3-D. The proposed method utilizes the two X-ray images in an integrated but differentiated way in order to best utilize the complementary information provided by the two types of images. A hierarchical registration scheme is deployed by a sensible partition of the registration parameter space based on the image acquisition protocol. The proposed method was validated using both synthetic and clinical datasets, and achieved significantly improved accuracy and robustness compared to the conventional methods.

Simulation of Intra-Aneurysmal Blood Flow by Different Numerical Methods

The occlusional performance of sole endoluminal stenting of intracranial aneurysms is controversially discussed in the literature. Simulation of blood flow has been studied to shed light on possible causal attributions. The outcome, however, largely depends on the numerical method and various free parameters. The present study is therefore conducted to find ways to define parameters and efficiently explore the huge parameter space with finite element methods (FEMs) and lattice Boltzmann methods (LBMs). The goal is to identify both the impact of different parameters on the results of computational fluid dynamics (CFD) and their advantages and disadvantages. CFD is applied to assess flow and aneurysmal vorticity in 2D and 3D models. To assess and compare initial simulation results, simplified 2D and 3D models based on key features of real geometries and medical expert knowledge were used. A result obtained from this analysis indicates that a combined use of the different numerical methods, LBM for fast exploration and FEM for a more in-depth look, may result in a better understanding of blood flow and may also lead to more accurate information about factors that influence conditions for stenting of intracranial aneurysms.