Laser-cut Stents Research Articles

Appraisal of the Flow Diversion Effect Provided by Braided Intracranial Stents.

Objective: Comparison of the results of stent-assisted coiling (SAC) with braided stents (BS), flow diverters (FD), and laser-cut stents (LCS) to determine the relative flow-diverting capacity of BS (Leo baby and Accero). Methods: Saccular intracranial aneurysms treated by SAC and FD-assisted coiling were retrospectively evaluated. Aneurysm occlusion, as graded per Raymond-Roy score, was categorized as either recanalization/stable residual filling (Group A; lacking a flow diversion effect) or stable/progressive occlusion (Group B with a "flow diversion effect"). Factors predicting the flow diversion effect were evaluated. Results: Of the 194 aneurysms included, LCS, BS, and FD were used in 70 (36.1%), 86 (44.3%), and 38 (19.6%) aneurysms, respectively. Aneurysms treated by FD were larger, had wider necks, and were located on larger parent arteries (p < 0.01, 0.02, and <0.01, respectively). The mean imaging follow-up duration was 24.5 months. There were 29 (14.9%) aneurysms in Group A and 165 (85.1%) in Group B. Among a spectrum of variables, including sex, age, aneurysm size, neck width, parent artery diameter, follow-up duration, and stent type, the positive predictors for stable/progressive aneurysm occlusion were aneurysm size and placement of an FD or BS (p < 0.01 and p < 0.01, respectively, and were positive predictors over LCS: ORs 6.34 (95% CI: 1.62-24.76) and 3.11 (95% CI: 1.20-8.07), respectively) in multivariate analysis. Conclusions: The placement of BS was a predictor of flow diversion over laser-cut stents. However, the flow diversion effect was approximately half that of FDs, suggesting that BS may only be considered to have some (partial) flow diversion effects.

Mid-term outcomes in stent-assisted coil embolization for ruptured cerebral aneurysms in the acute period: A single institution retrospective review

ObjectiveThe purposes of this study were to retrospectively review mid-term outcomes of stent-assisted coil embolization for acutely ruptured cerebral aneurysms, and to identify risk factors. MethodsBetween April 2013 and October 2018, thirty-four consecutive patients had stent-assisted coil embolization for treatment of acutely ruptured cerebral aneurysms that were not amendable by simple coiling. Hospital subarachnoid hemorrhage registry and notes on hospital electronic medical systems were retrospectively reviewed. All patients had a dose of intravenous abciximab 10 mg and heparin 2000 units before stenting and started dual antiplatelet therapy after procedure. ResultsOf the thirty-four consecutive patients, twenty-six (76 %) were treated with braided stents and eight (24 %) were treated with laser-cut stents. There was no rebleeding in thirty-two patients who achieved total aneurysmal occlusion or residual neck only. Rebleeding occurred in two patients who only achieved partial embolization, resulting in mortality. There were three (9 %) thromboembolic complications, in which two were ADL-independent upon hospital discharge and the one with WFNS Grade V succumbed. Twenty (59 %) patients achieved clinical favorable outcomes (mRS 0–2) at follow-up (mean+/-SD: 17+/-15 months). The need of EVD insertion was a statistically significant risk factor for procedure-related cerebral infarction, intracerebral hemorrhage and 30-day mortality. The GOS and mRS were closely related to the need of EVD insertion and sidewall location of aneurysm. ConclusionsThe study established the efficacy and safety profile of stent-assisted embolization for treatment acutely ruptured cerebral aneurysms. The embolization goal should be total aneurysmal occlusion or with minimal residual neck to prevent rebleeding and reduce mortality. The use of such technique should be considered when simple coiling or microsurgical clipping is not feasible or suitable. The need of EVD insertion is an independent risk factor for intracerebral hematoma and 30-day mortality. When needed, EVD insertion shall be considered before antiplatelet agents, and require exceptionally meticulous hemostasis intraoperatively.

Enhancing thromboresistance of neurovascular nickel-titanium devices with responsive heparin hydrogel coatings

BackgroundNeurointerventional devices, particularly laser-cut thin-strut stents made of self-expanding nickel-titanium alloy, are increasingly utilized for endovascular applications in intracranial arteries and dural venous sinuses. Preventing thrombosis and stroke necessitates systemic...

The pEGASUS-HPC stent system for intracranial arterial stenosis: a single-center case series

BackgroundIntracranial arterial stenting is a technique for the treatment of symptomatic stenosis. In this single-center retrospective case series we evaluated a novel low profile laser-cut stent with an antithrombogenic hydrophilic...

Shape-Setting of Self-Expanding Nickel–Titanium Laser-Cut and Wire-Braided Stents to Introduce a Helical Ridge

PurposeAltered hemodynamics caused by the presence of an endovascular device may undermine the success of peripheral stenting procedures. Flow-enhanced stent designs are under investigation to recover physiological blood flow patterns in the treated artery and reduce long-term complications. However, flow-enhanced designs require the development of customised manufacturing processes that consider the complex behaviour of Nickel-Titanium (Ni-Ti). While the manufacturing routes of traditional self-expanding Ni–Ti stents are well-established, the process to introduce alternative stent designs is rarely reported in the literature, with much of this information (especially related to shape-setting step) being commercially sensitive and not reaching the public domain, as yet.MethodsA reliable manufacturing method was developed and improved to induce a helical ridge onto laser-cut and wire-braided Nickel–Titanium self-expanding stents. The process consisted of fastening the stent into a custom-built fixture that provided the helical shape, which was followed by a shape-setting in air furnace and rapid quenching in cold water. The parameters employed for the shape-setting in air furnace were thoroughly explored, and their effects assessed in terms of the mechanical performance of the device, material transformation temperatures and surface finishing.ResultsBoth stents were successfully imparted with a helical ridge and the optimal heat treatment parameters combination was found. The settings of 500 °C/30 min provided mechanical properties comparable with the original design, and transformation temperatures suitable for stenting applications (Af = 23.5 °C). Microscopy analysis confirmed that the manufacturing process did not alter the surface finishing. Deliverability testing showed the helical device could be loaded onto a catheter delivery system and deployed with full recovery of the expanded helical configuration.ConclusionThis demonstrates the feasibility of an additional heat treatment regime to allow for helical shape-setting of laser-cut and wire-braided devices that may be applied to further designs.

The pEGASUS-HPC stent system for stent-assisted coiling of cerebral aneurysms: a multicenter case series

BackgroundStent-assisted coiling (SAC) is a well-established method for treatment of wide-necked intracranial aneurysms. In this multicenter, retrospective case series we evaluated SAC with a new low-profile, laser-cut stent with an...

Abstract 15472: The IRIS™ Valve: A Growth Accommodating Transcatheter Pulmonary Valve for Pediatric Patients

Introduction: It is estimated that at least 1 million children are living with a congenital heart defect (CHD) in the U.S. Most of these patients are born with some degree of right ventricular outflow tract (RVOT) abnormalities that at some point require pulmonary valve replacement to mitigate the detrimental effects of pulmonary valve regurgitation (PVR) on the right ventricle (RV). Due to their size, available solutions, e.g., the Melody™ valve (Medtronic Inc., Minneapolis, MN) cannot be implanted in small children under 20 Kg. Those must wait until they grow to a suitable weight to receive the valve, which may lead to RV dysfunction. Hypothesis: To mitiagte the detrminental effects to the RV, the IRIS™ valve is implantable at 12 mm with a 12-Fr delivery catheter. As the valve annulus grows, the valve would be balloon expanded up to 20 mm. Methods: The IRIS™ valve has been designed according to origami concepts such that its three leaflets would retain a fully-coapted form as it is expanded to a larger size. Here we report our methods and results of implantation in 9-17Kg Yucatan pigs. Results: The IRIS™ valve is made of thin porcine pericardial leaflets sewn into a laser-cut stainless-steel stent. The stented valve is covered with an ePTFE skirt to mitigate paravalvular leak. The IRIS™ valve is fully crimped over a 12-Fr delivery catheter for transfemoral implantation. We have successfully implanted the valve at the native pulmonary valve position with minimal regurgitation in three pigs ranging from 9 to 17kg with varying pulmonary annulus sizes. Conclusions: The IRIS™ transcatheter pulmonary valve has been successfully developed according to proprietary origami concepts. Using the 12Fr delivery catheter, the smallest delivery profile reported, we successfully implanted the IRIS™ valve within the pulmonary annulus of mini pigs with encouraging results.

Safety of discontinuing antiplatelet therapy 12-24 months after stent-assisted coil embolization: a multicenter retrospective study.

Antiplatelet medication is required after stent-assisted coil embolization (SACE) to avoid thromboembolic complications. Currently, there is no consensus on how long the antiplatelet agent should be maintained. The authors investigated clinical outcomes in patients who discontinued their antiplatelet agent 12-24 months after SACE. Data were retrieved from a prospective database for 373 consecutive patients with SACE at 6 institutions who discontinued antiplatelet therapy 12-24 months after SACE. Thromboembolic complications associated with discontinuation were defined as neurological or radiographic ischemia that occurred within 6 months after discontinuation of the antiplatelet agent; the lesion had to be correlated with the territory of the stented artery. The mean time until discontinuation of the antiplatelet medication was 15.8 ± 4.7 months after SACE (12-18 months, n = 271; 19-24 months, n = 102). The most common location of treated aneurysms was the internal carotid artery (n = 223, 59.8%). A laser-cut open-cell stent was most commonly applied (n = 236/388, 60.8%), followed by laser-cut closed-cell stents (n = 119, 30.7%) and braided closed-cell (n = 33, 8.5%); double stenting was applied in 15 aneurysms. There were no patients who experienced cerebral ischemia related to discontinuation of antiplatelet medications, except for 1 patient at high risk of ischemia (0.27%, 95% CI 0.01%-1.48%). These results suggest that it may be safe to discontinue antiplatelet medication after SACE in patients at low risk for ischemia, and that it appears safe to discontinue the agent at approximately 15 months after the procedure. Large cohort-based prospective studies or randomized clinical trials are warranted to confirm these results.

The evaluation of bilateral stenting using braided or laser-cut self-expandable metallic stent for malignant hilar biliary obstruction.

Bilateral self-expandable metallic stent (SEMS) placement for unresectable malignant hilar biliary obstruction (UMHBO) is an effective option for biliary drainage with long-term stent patency. Laser-cut and braided SEMS can be used for bilateral SEMS placement. This study aimed to clarify any differences in the clinical features and proper use of the laser-cut and braided SEMS placement using the stent-in-stent method for UMHBO. In this study, 78 patients who underwent bilateral stent-in-stent SEMS placement for UMHBO were included. The patients were divided into the laser-cut (n = 33) and braided groups (n = 45). Both groups were compared for technical and clinical success, adverse events (AEs), time to recurrent biliary obstruction (TRBO), overall survival, and endoscopic reintervention (ERI). There were no significant differences in technical and clinical success rates (laser-cut vs. braided group, 97% vs. 95.6%, P = 1.0), AEs (21.2% vs. 15.6%. P = 0.56), median TRBO (242days vs. 140days, P = 0.36), and median overall survival (654days vs. 675days, P = 0.58). ERI was required in 15 patients in the laser-cut group and in 20 patients in the braided group. The technical and clinical success rates of ERI (60% vs. 85%) were not significantly different (P = 0.13); however, the median ERI procedure time was significantly longer in the laser-cut group (38min) than in the braided group (22min; P = 0.02). No significant difference in initial SEMS placement was noted between the laser-cut and braided groups; however, the laser-cut group required a longer ERI procedure time than that required by the braided group. The use of braided SEMS may be a convenient option for ERI.

Single centre experience of stent-assisted coiling of wide-necked basilar tip aneurysms.

To report clinical and radiological follow-up outcomes of stent-assisted coiling of wide-necked basilar tip aneurysms and to evaluate the safety and efficacy of this treatment choice. A retrospective review was carried out of 19 patients with wide-necked basilar tip aneurysms in our institution between 2010 and 2020. The rates of perioperative complication, morbidity, mortality, imaging follow-up and re-treatment were analysed. Our technical complication rate was 11% but did not result in treatment failure. The combined procedure related morbidity and mortality rate of the 19 patients who underwent stent assisted coiling was also 11%. 16 of 19 patients had undergone angiographic follow-up with a mean period of 32 months. 81% of patients with angiographic follow-up had a satisfactory occlusion (RROI or II) with 11% requiring re-treatment. Those requiring re-treatment were both treated with laser-cut stents; this is in contrast with no re-treatments required in the patients treated with braided stents. Our report provides acceptable outcomes in wide-necked basilar termination aneurysms which are very challenging to treat. Aneurysms treated with braided stents had better efficacy outcomes than those with laser-cut stents. Given the emergent and increasing utility of alternative endovascular techniques such as intrasaccular devices and flow diverters, real-world data are lacking on more conventional approaches such stent-assisted coiling, especially so in the posterior circulation. The associated relatively higher aneurysmal haemorrhagic risk in this location warrants further additional safety and efficacy data for this treatment approach, which this paper provides.

Angiographic outcomes of embolization in patients with intracranial aneurysms with coil- assisted Laser cut stent versus braided stents.

Intracranial aneurysms (IA) are a focal dilatation of the vessel wall, the rupture of these, causes subarachnoid hemorrhage. Until now, endovascular management is the ideal treatment, providing the interventionist a range of options among which the stent and coils embolization stands out because of its occlusion rate. This study presents the results of a retrospective cohort comparing the effectiveness, morbidity, and mortality of IA treatment with laser-cut stent-assisted coils versus braided stents. Retrospective cohort of patients diagnosed with unruptured intracranial aneurysms treated with coil-assisted laser-cut stents or braided stents between January 2014 and December 2021. In total, 138 patients with 147 intracranial aneurysms were analyzed, 91 of them were treated with laser-cut stent and 56 with braided stents. The main antecedent was arterial hypertension (48.55%). In the immediate angiographic control, a Raymond Roy scale (RRO) I was obtained in 86.81% of the patients with laser-cut stents and 87.50% of the patients with braided stents. In the angiographic follow-up at 12 months, an RRO I occlusion rate of 85.19% was reported in both groups. Perioperative complications occur in 16 patients treated with laser-cut stents and 12 patients treated with braided stents. Three patients presented bleeding complications during the 12-month follow-up, of which two correspond to patients treated with braided stents and one with a laser-cut stent. Treatment of patients with intracranial aneurysms with laser-cut stents or braided stents and coils is just as safe and effective.

Finite element analysis of braided dense-mesh stents for carotid artery stenosis

When braided dense-mesh stents are used to treat carotid stenosis, the structural mechanics of vascular stents, the contact mechanics with blood vessels, and the fluid mechanics in the blood environment need to be studied in depth to reduce the damage of stents to blood vessels and the incidence of in-stent restenosis. Three types of braided stents with 8, 16, and 24 strands and laser-cut stents with the corresponding size parameters were designed, and the bending behavior of each of these types of stent, deployment, and fluid dynamic analysis of the 24-strand braided stent were simulated. The results show that the bending stress of the 8-, 16-, and 24-strand braided stents is 46.33%, 50.24%, and 31.86% of that of their laser-cut counterparts. In addition, higher strand density of the braided stents was associated with greater bending stress; after the 24-strand braided stent was expanded within the stented carotid artery, the carotid stenosis rate was reduced from 81.52% to 46.33%. After stent implantation, the maximum stress on the vessel wall in a zero-pressure diastolic environment decreased from 0.34 to 0.20 MPa, the maximum pressure on the intravascular wall surface decreased from 4.89 to 3.98 kPa, the area of high-pressure region decreased, the wall shear force of the stenotic segment throat decreased, and blood flow increased in the stenosis segments. The braided stent had less bending stress and better flexibility than the laser-cut stent under the same stent size parameters; after the 24-strand braided stent was implanted into the stented vessel, it could effectively dilate the vessel, and the blood flow status was improved.

Removal of Duckbill-type laser-cut anti-reflux metal stents: Clinical evaluation and in vitro study.

Duckbill-type metal stent (DMS) was the first laser-cut biliary metal stent with an anti-reflux valve. Removal of DMS is believed to be difficult and relevant reports are scarce. This study aims to investigate the feasibility of DMS removal. We retrospectively analyzed patients who underwent DMS removal between June 2019 and March 2022 to evaluate success rates and factors affecting outcomes. In addition, six different methods of DMS removal were reproduced in vitro, varying removal devices, angle of applied force, and grasped location. Extraction resistance, the distance of forceps stroke, and stent length after removal were compared. Forty patients were enrolled, and DMS removal was successful in 31 cases (78%). No adverse events were observed. Tumor ingrowth was evident in 78% (7/9) of failed cases. Patients receiving biliary metal stents for the first time (naïve cases), long indwelling time, longer stent, and stent tearing during removal were associated with unsuccessful stent removal. In the in vitro study, a larger force was required to remove the stent at an extraction angle of 120° than at 0°. Among cases in which force was applied at 120°, the load tended to be lower when rat-tooth forceps were applied horizontally across the stent. Stent removal was possible in a majority of cases. Deployment of additional stents inside DMS may be preferable to forceful removal in the presence of factors associated with difficult stent removals, such as tumor ingrowth, naïve cases, longer stents, long indwelling time, and stent tearing during removal.

Procedural outcome following and Hemodynamic imaging analysis for anterior communicating artery wide-necked aneurysms by four different stents assisted coil embolization

Background: Anterior communicating artery (AcomA) aneurysm is the most common intracranial aneurysm (IA) and has the highest rupture rate. Previously, the preferred surgical treatment for intracranial aneurysms was microsurgery clipping (MC). With the gradual maturation of endovascular treatment (EVT), an increasing number of patients are inclined to treat IA with EVT. In recent years, an increasing number of scholars have suggested that the preferred treatment for wide-necked aneurysms is stent-assisted coiling (SAC). Currently, there are few studies on comparative analyses of the procedural results of SAC in AcomA aneurysms.Methods: We retrospectively reviewed all consecutively treated patients who received SAC for AcomA aneurysms between 12 February 2013, and 20 January 2021. The primary procedural outcome was the occlusion rate evaluated with the Raymond–Roy occlusion classification (RROC) assessed on DSA at follow-up. Safety assessment included 1) ischemic complications (asymptomatic ischemia; intrastent thrombosis; coils falling off plug; arterial dissection); 2) bleeding complications (SAH; ICH); and 3) death. Univariate and multivariate logistic regression analyses were performed to determine patient baseline and aneurysm characteristics associated with total aneurysm occlusion at follow-up. Hemodynamic analysis was performed in one representative case each of the four stents, and six hemodynamic parameters were chosen, including wall shear stress (WSS), cavity blood flow velocity (CBFV), residual blood in the aneurysm (RBA), neck blood flow velocity (NBFV), blood flow inflow (BFI); and inflow concentration index (ICI).Results: A total of 154 patients who underwent EVT via SAC were enrolled for comparative analysis of procedural outcomes. The median age was 55 years, and 56.49% (87) were female. At the first (6–10 months), second (12–15 months) and last (24–48 months) follow-up, complete aneurysm occlusion was observed in 94.8%, 94.8%and 94.2% of patients, respectively. There were no differences regarding the occlusion rates stratified by stent. Each stent showed a variable decrease in all hemodynamic parameters.Conclusion: Hemodynamic parameters all decreased significantly after SAC with all four different stents, and the effect of laser-cut stents on the hemodynamic decline of aneurysms appeared to be more significant than that of woven stents. No significant difference was observed in the follow-up RROC grade among the four stents.

Braided stent-assisted coil embolization versus laser engraved stent-assisted coil embolization in patients with unruptured complex intracranial aneurysms

PurposesBraided and laser-cut stents both are efficacious and safe for coiling intracranial aneurysms. The study aimed to compare outcomes following braided stent-assisted coil embolization versus laser engraved stent-assisted coil embolization in 266 patients who were diagnosed with unruptured intracranial aneurysms of different types and locations. MethodsPatients with unruptured complex intracranial aneurysms underwent braided (BSE cohort, n = 125) or laser engraved (LSE cohort, n = 141) stent-assisted embolization. ResultsThe deployment success rate was higher for patients of the LSE cohort than those of the BSE cohort (140 [99%] vs. 117 [94%], p = 0.0142). Seventy-one (fifty-seven percentages) and 73 (52%) were coil embolization procedure success rates of the BSE and the LSE cohorts. Periprocedural intracranial hemorrhage was higher in patients of the BSE cohort than those of the LSE cohort (8 [6%] vs. 1 [1%], p = 0.0142). Four (three percentages) patients from the LSE cohort and 3 (2%) patients from the BSE cohort had in-stent thrombosis during embolization. Permanent morbidities were higher in patients of the LSE cohort than those of the BSE cohort (8 [6%] vs. 1 [1%], p = 0.0389). Higher successful procedures (76% vs. 68%) and fewer postprocedural intracranial hemorrhage (0% vs. 5%) and mortality (0% vs. 5%) were reported for patients of the BSE cohort in posterior circulation aneurysmal location than those of the LSE cohort. Laser engraved stent has fewer problems with deployment and may have better periprocedural and follow-up outcomes after embolization. ConclusionsBraided stent-assisted embolization should be preferred when the aneurysm is present in the posterior circulation.

The resolute Onyx drug eluting stent for neurointervention: A technical series.

Current methods for angioplasty and stenting of the intracranial vasculature for neurointervention are limited. The Wingspan Stent System is Food and Drug Administration (FDA) approved with human device exemption for a limited patient group and despite numerous prospective registries and trials demonstrating reasonable safety, still carries warnings from the FDA for its use. Given these limitations, we present the technical nuances and outcomes of the off-label use of the Resolute Onyx drug-eluting stent (DES) for neurointerventional purposes. Retrospective chart review of all patients undergoing a neurointerventional procedure with the Resolute Onyx DES was done from January 2017-2021. The Resolute Onyx is a coronary balloon-mounted drug-eluting (zotarolimus) single wire laser cut stent. Technical details and procedural outcomes were collected. In total 40 patients had attempted placement of the Resolute Onyx DES with procedural success in 95% of patients. The most common vessel stented was the basilar artery, 30% (12/40). The most common indication was intracranial atherosclerotic disease in 62.5% (25/40) patients, followed by acute stroke in 17.5% (7/40) of patients. The technical and procedural outcomes were excellent with only one technical complication (2.5%). This series describes the initial technical safety and utility of utilizing a new generation balloon-mounted drug-eluting stent for neurointerventional purposes. This stent offers the potential for improved navigability, delivery, and outcomes compared to current neurointerventional options and warrants further study.

Is it safe to discontinue antiplatelet medication after stent-assisted coil embolization? If so, when is the best time?

PurposeAntiplatelet maintenance after stent-assisted coil embolization (SACE) is generally considered essential to avoid post-procedural thromboembolic complications. However, there is still debate as to whether it is safe to discontinue antiplatelet drugs after SACE or when is the best time to do so. We investigate herein the clinical outcomes experienced by patients who discontinue antiplatelet agents after SACE. MethodsFrom a prospective database, we retrieved the data for 120 consecutive patients (harboring 130 aneurysms) in whom antiplatelet agents were discontinued after SACE between January 2010 and December 2019. We defined thromboembolic complications associated with discontinuation as neurologic or radiographic ischemia that occurred within 6 months of discontinuation of antiplatelet agents; the lesion was required to be correlated with the stented artery. ResultsThe mean time of discontinuation of antiplatelet medication was 31.4 ± 18.3 months after SACE (median, 26 months). The majority of patients stopped antiplatelet medication between 18 and 36 months after SACE (74 patients, 61.6%). Laser-cut closed-cell stent was most commonly applied in 91 aneurysms (70.0%), followed by braided closed-cell (n=29; 22.3 %) and laser-cut open-cell stent 10 (7.7 %). No patients experienced cerebral ischemia related to discontinuation of antiplatelet medication. ConclusionOur preliminary study suggests that it may be safe to discontinue antiplatelet medication after SACE in patients at low risk for ischemia. The optimal time to discontinue might be around 18 to 36 months after SACE. Large cohort-based studies or randomized clinical trials are warranted to confirm these results.

Mechanical characteristics of venous stents to overcome challenges of venous outflow obstruction.

Many challenges posed by the venous outflow obstruction (VOO) are unique to the venous system which require specific mechanical characteristics of stents to overcome them. Therefore, this article aims to review and discuss these challenges and the stent mechanical characteristics required to overcome them. A literature search was performed with Pubmed with the terms "mechanical characteristics of venous stents" and "mechanical properties of venous stents". The venous system poses unique anatomical, physiological and pathological challenges when compared to the arterial counterpart. Several mechanical characteristics specific to venous stents which include the size, inherent forces, and flexibility are important to overcome these unique challenges when treating VOO. The most important stent inherent forces for venous stents include the chronic outward force, radial resistive force, and crush resistance. Various stent materials and designs, particularly laser-cut versus braided-structure stents, and open-cell versus closed-cell stents, determine the mechanical characteristics including the inherent forces of the venous stents. The desired mechanical characteristics of stents needed to overcome the venous system challenges often in conflict or with opposing effects. Therefore, it is important to fine adjust and optimize these characteristics. There are many anatomical, physiological, and pathological challenges unique to the venous system which need to be overcome by the stent system mechanically when treating VOO. Therefore, dedicated venous stents with optimal mechanical characteristics are being developed with different designs and properties to treat VOO. Further research and innovations are needed to improve the stent technology that targets the venous system specifically.

Low-profile visualized intraluminal support stent for the endovascular treatment of traumatic intracranial internal carotid artery pseudoaneurysms.

Optimal treatment strategies for traumatic intracranial internal carotid artery (ICA) pseudoaneurysms are controversial. The low-profile visualized intraluminal support (LVIS) device is a braided stent with a metal coverage rate between traditional laser cut stents and flow diversion devices. We report here our therapy strategy using the LVIS stent-assisted coiling for treatment of traumatic intracranial ICA pseudoaneurysms. Patients with traumatic intracranial ICA pseudoaneurysms treated by the LVIS stent-assisted coiling in our center between January 2015 and June 2021 were reviewed. The complications, radiographic, and clinical outcomes of these patients were analyzed. A total of 12 patients with 12 pseudoaneurysms were included. The mean maximum aneurysm diameter was 6.2 ± 3.1mm. Nine patients had a subarachnoid hemorrhage; five patients with Hunt-Hess grade III and four patients with grade IV. All procedures were successfully performed without intraoperative complications. Immediate postoperative angiogram showed that six (50%) aneurysms were Raymond grade 1, four (33.3%) were grade 2, and two (16.7%) were grade 3. Postoperative multiple cerebral infarction occurred in two patients because of vasospasm. Of the ten patients with angiographic follow-up (mean, 29.9months), two received additional coiling because of recanalization of the pseudoaneurysm, and all aneurysms were completely obliterated at the last examination of the patients. During the clinical follow-up period (mean, 26.8months), the overall mortality and morbidity were 25% (3/12) and 8.3% (1/12), respectively. LVIS stent-assisted coiling was a feasible approach for the treatment of traumatic ICA pseudoaneurysms.

Superficial femoral artery stenting: Impact of stent design and overlapping on the local hemodynamics

BackgroundSuperficial femoral arteries (SFAs) treated with self-expanding stents are widely affected by in-stent restenosis (ISR), especially in case of long lesions and multiple overlapping devices. The altered hemodynamics provoked by the stent is considered as a promoting factor of ISR. In this context, this work aims to analyze the impact of stent design and stent overlapping on patient-specific SFA hemodynamics. MethodsThrough a morphing technique, single or multiple stents were virtually implanted within two patient-specific, post-operative SFA models reconstructed from computed tomography. The stented domains were used to perform computational fluid dynamics simulations, quantifying wall shear stress (WSS) based descriptors including time-averaged WSS (TAWSS), oscillatory shear index (OSI), transverse WSS (transWSS), and WSS ratio (WSSRATIO). Four stent designs (three laser-cut – EverFlex, Zilver and S.M.A.R.T. – and one prototype braided stent), and three typical clinical scenarios accounting for different order of stent implantation and overlapping length were compared. ResultsThe main hemodynamic differences were found between the two types of stent designs (i.e. laser-cut vs. braided stents). The braided stent presented lower median transWSS and higher median WSSRATIO than the laser-cut stents (p < 0.0001). The laser-cut stents presented comparable WSS-based descriptor values, except for the Zilver, exhibiting a median TAWSS ∼30% higher than the other stents. Stent overlapping provoked an abrupt alteration of the WSS-based descriptors. The overlapping length, rather than the order of stent implantation, highly and negatively impacted the hemodynamics. ConclusionThe proposed computational workflow compared different SFA stent designs and stent overlapping configurations, highlighting those providing the most favorable hemodynamic conditions.