Open-cell Stent Research Articles

An investigation into patient-specific 3D printed titanium stents and the use of etching to overcome Selective Laser Melting design constraints

Due to limitations in available paediatric stents for treatment of aortic coarctation, adult stents are often used off-label resulting in less than optimal outcomes. The increasingly widespread use of CT and/or MR imaging for pre-surgical assessment, and the emergence of additive manufacturing processes such as 3D printing, could enable bespoke devices to be produced efficiently and cost-effectively. However, 3D printed metallic stents need to be self-supporting leading to limitations in their design.In this study, we investigate the use of etching to overcome these design constraints and improve stent surface finish. Furthermore, using a combination of experimental bench testing and finite element (FE) methods we investigate how etching influences stent performance. Then using an inverse finite element approach the material properties of the printed and etched stents were calibrated and compared. We show that without etching the titanium stents, the inverse FE approach underestimates the stiffness of the as-built stent (E = 33.89 GPa) when compared to an average of 76.84 GPa for the etched stent designs. Finally, using patient-specific finite element models the different stents’ performance were tested to assess patient outcomes and lumen gain and vessel stresses were found to be strongly influenced by the stent design and postprocessing.Within this study, etching is confirmed as a means to create open-cell stent designs whilst still conforming to additive manufacturing ‘rules’ and concomitantly improving stent surface finish. Additionally, the feasibility of using an in-vivo imaging-to-product development pipeline is demonstrated that enables patient-specific stents to be produced for varying anatomies to achieve optimum device performance.

Performance of Open and Closed Cell Laser Cut Nitinol Stents for the Treatment of Chronic Iliofemoral Venous Outflow Obstruction in Patients Treated at a Single Centre

A number of dedicated self expanding nitinol stents have been developed for use in the venous system, with both open cell (OC) and closed cell (CC) designs available. Data comparing these different designs are lacking. The objective of this study was to evaluate outcomes in patients treated with open and closed cells for unilateral chronic iliac vein obstruction. A single centre retrospective cohort study was conducted, including all patients treated with a dedicated nitinol venous stent between 2014 and 2019. Stent patency and details of re-interventions (including lysis, venoplasty, reinforcement, extension, arteriovenous fistula formation) were examined in the first post-operative year. Subgroup analysis described outcomes for patients treated with OC and CC stents ending above the inguinal ligament and those who required extension into the common femoral vein. Cox regression analysis was used to identify factors associated with loss of primary patency. A total of 207 patients were included (OC 100 patients, CC 107 patients). There was no significant difference between the groups for age (OC 42 years, CC 44 years); gender (OC and CC 67% female); presence of post-thrombotic lesions (OC 71%, CC 73%); stenting across the inguinal ligament (OC 58%, CC 56%), or presence of inflow disease (OC 49%, CC 47%). Primary and cumulative patency at 12 months were similar between groups (primary: OC 63%, CC 65%; cumulative: OC 93%, CC 90%). Patients with a CC stent across the inguinal ligament had a greater risk of needing multiple re-interventions at one year compared with those with an OC stent (odds ratio 2.84, 95% confidence interval [CI] 1.16 – 6.9) but overall, the only factor significantly associated with loss of primary patency was inflow vessel disease (hazard ratio 3.39, 95% CI 1.73 – 6.62, p < .001). OC and CC dedicated nitinol venous stents were observed to perform similarly in terms of patency and symptom improvement at one year. Disease of the inflow vessels was the most important factor associated with a loss of stent patency irrespective of stent design.

Asymptomatic Cerebral Emboli Following Carotid Artery Stenting: A Diffusion-Weighted MRI Study

BackgroundSilent cranial embolism due to carotid artery stenting has been demonstrated to cause dementia, cognitive decline, and even ischemic stroke. The purpose of this study was to compare the periprocedural asymptomatic cranial embolism rates of different stent designs used for extracranial carotid stenosis with diffusion-weighted magnetic resonance imaging.MethodsA total of 507 consecutive patients who underwent carotid artery stenting at our center from December 2010 to June 2020 (mean age, 66.4 ± 9.5) were analyzed retrospectively. The patients were divided into 3 groups as open-cell stent (334 patients), closed-cell stent (102 patients), and hybrid-cell stent (71 patients) groups. Diffusion-weighted magnetic resonance imaging was performed for the patients before and after carotid artery stenting and compared. The diffusion limitations of 3 stent groups on cranial diffusion-weighted magnetic resonance imaging were compared with one another.ResultsPeriprocedural asymptomatic same-side microembolism, which was the primary endpoint of our study, was detected in 58 (17.4%) patients in the open-cell stent group, 6 (5.9%) patients in the closed-cell group, and 8 (11.3%) patients in the hybrid cell group, and overall in 72 (14.2%) patients. On diffusion-weighted magnetic resonance imaging, periprocedural asymptomatic same-side cranial embolism was found to be statistically significantly higher in the open-cell group compared to the other two groups (P = .011).ConclusionsThe result of this study showed us that the rate of same-side cranial embolism detected on cranial diffusion-weighted magnetic resonance imaging after carotid artery stenting performed with open-cell stent was higher than those of the carotid artery stenting procedure performed with closed-cell and hybrid-cell stents.

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.

Feasibility and Results of the Stentectomy Procedure Performed as Rescue Treatment for Acute Thrombosis of Self-Expandable Intracranial Stents: A Case Series.

Self-expandable stents have been increasingly used for endovascular treatment of intracranial aneurysms. Because the usage of intracranial stents has increased overall, total numbers of complications associated with these devices have increased. Thrombosis, distortion, or incomplete opening of stents are potential complications that may result in occlusion of the parent artery. In such cases, removal of the stent (stentectomy) may be the only solution to avoid serious clinical consequences. To investigate the feasibility and efficacy of a novel stentectomy technique for removal of thrombosed self-expandable stents. A retrospective review was performed of patients who underwent the stentectomy procedure. Initial and follow-up imaging and clinical outcomes were assessed. Immediate postprocedural and follow-up clinical statuses were assessed using the modified Rankin scale. Seven patients were included in this study (mean age: 54.1 years). The stentectomy was successful in 6 of 7 patients (85.7%). Seven stents in 6 patients were successfully removed to treat the acute in-stent thrombosis that was resistant to alternative bail-out treatments. The removed stents were self-expandable braided in 2 patients, flow diverters in 2 patients, and laser cut open-cell stents in 2 patients. Stentectomy failed to retrieve a thrombosed braided stent in 1 patient. The modified Rankin scale score of all patients who underwent a success stentectomy was ≤1. The stentectomy procedure using the defined technique is feasible to retrieve thrombosed stents and effective to restore the blood flow. It can be considered a last resort option to treat acute in-stent thrombosis resistant to alternative bail-out treatments.

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.

Performance of Open and Closed Cell Laser Cut Nitinol Stents for the Treatment of Chronic Iliofemoral Venous Outflow Obstruction in Patients Treated at a Single Centre

A number of dedicated self expanding nitinol stents have been developed for use in the venous system, with both open cell (OC) and closed cell (CC) designs available. Data comparing these different designs are lacking. The objective of this study was to evaluate outcomes in patients treated with open and closed cells for unilateral chronic iliac vein obstruction. A single centre retrospective cohort study was conducted, including all patients treated with a dedicated nitinol venous stent between 2014 and 2019. Stent patency and details of re-interventions (including lysis, venoplasty, reinforcement, extension, arteriovenous fistula formation) were examined in the first post-operative year. Subgroup analysis described outcomes for patients treated with OC and CC stents ending above the inguinal ligament and those who required extension into the common femoral vein. Cox regression analysis was used to identify factors associated with loss of primary patency. A total of 207 patients were included (OC 100 patients, CC 107 patients). There was no significant difference between the groups for age (OC 42 years, CC 44 years); gender (OC and CC 67% female); presence of post-thrombotic lesions (OC 71%, CC 73%); stenting across the inguinal ligament (OC 58%, CC 56%), or presence of inflow disease (OC 49%, CC 47%). Primary and cumulative patency at 12 months were similar between groups (primary: OC 63%, CC 65%; cumulative: OC 93%, CC 90%). Patients with a CC stent across the inguinal ligament had a greater risk of needing multiple re-interventions at one year compared with those with an OC stent (odds ratio 2.84, 95% confidence interval [CI] 1.16 - 6.9) but overall, the only factor significantly associated with loss of primary patency was inflow vessel disease (hazard ratio 3.39, 95% CI 1.73 - 6.62, p < .001). OC and CC dedicated nitinol venous stents were observed to perform similarly in terms of patency and symptom improvement at one year. Disease of the inflow vessels was the most important factor associated with a loss of stent patency irrespective of stent design.

The Effect of Stent Design on Plaque Protrusion after Carotid Artery Stenting.

The association between stent design and post-stent intravascular findings after carotid artery stenting (CAS) was evaluated. Among the 79 patients who underwent CAS between March 2016 and June 2020 at our institution, we retrospectively analyzed 65 patients with full post-stent intravascular evaluation by both optical frequency domain imaging and angioscopy. All CAS procedures were performed under the flow reversal method, and the stent selection was determined by each operator's discretion, depending on the vessel anatomy or plaque characteristics. The patient's characteristics, plaque characteristics, ischemic complication, and post-stent intravascular findings (plaque protrusion, vessel wall apposition of stent) were compared between the closed-cell and open-cell stent groups. The closed-cell group (n = 34) had more high-risk plaques, such as symptomatic lesions or intraplaque hemorrhages, on MRI compared with the open-cell group (n = 31). There was no difference in the rate of ischemic complications between the groups. Although there was no difference in the frequency of plaque protrusion between the two, the maximum height of the protruded plaque was higher in the open-cell group (320 vs. 612 μm, p = 0.003) and incomplete apposition was higher in the closed-cell group (85.3 vs. 6.5%, p <0.0001). The open-cell stent provided better apposition but had larger plaque protrusion. The need for a new hybrid stent that combines the merits of both open- and closed-cell stents was suggested.

Abstract 1122‐000078: C‐Guard Stent for the Treatment of Cervical Internal Carotid Artery Aneurysms: Report of 2 Cases

Introduction : C‐Guard carotid stent is a self‐expandable open cell stent covered with a double‐layer mesh which was developed for the treatment of internal carotid artery disease. Lower procedural and complications rates, as well as lower post‐operative infarctions are some advantages of this device. Nevertheless, the use of C‐Guard in the treatment of cervical internal carotid artery (ICA) aneurysms is scarce. Therefore, we present two cases in which the C‐Guard stent achieved complete angiographic occlusion at follow‐up. Methods : We identified two cases in which the C‐Guard carotid stent was used to treat symptomatic cervical ICA aneurysms. Angiographic follow‐up was performed. Results : Case 1: 47‐yo female presented left‐sided motor deficit. CT showed ischemic areas in the right hemisphere and CTA demonstrated an unruptured aneurysm in the C1 segment of the right ICA. The patient started dual antiplatelet therapy (DAPT) with aspirin and clopidogrel. A 6mm x 40 mm C‐Guard carotid stent was deployed without complications. One‐year follow‐up CTA showed complete obliteration of the aneurysm with reconstruction of the ICA. Case 2: 38‐yo male presented decreased left visual acuity. CTA and DSA showed an unruptured aneurysm in the C1 segment of the ICA. The patient started DAPT with aspirin and clopidogrel. A 7mm x 30 mm C‐Guard carotid stent was deployed without complications. Three‐month follow‐up DSA showed complete obliteration of the aneurysm with adequate filling of distal vessels. Conclusions : C‐Guard stent is a potential alternative to conventional carotid stents in the treatment of cervical ICA aneurysms with high obliteration rates at follow‐up.

Carotid stenting in Nepal: Our experience with two cases of carotid stenosis

Carotid artery stenosis is one of the important risk factors for stroke. Carotid endarterectomy and carotid artery stenting are the available treatment options for managing carotid artery stenosis patients. The technology shift towards carotid artery stenting is promising due to its less invasive approach. Carotid artery stenting has become an alternative for surgically high-risk patients and high carotid lesions (lesions located at or above the second cervical vertebra). Here, we present two cases with carotid artery stenosis who were successfully treated with open-cell type carotid stent with distal filter embolic protection device.

Selective laser melting of NiTi stents with open-cell and variable diameter

This work investigates the processing of NiTi open-cell peripheral stents with variable diameter by SLM and consecutive heat treatments. The production of open-cell designs via SLM requires dedicated processing strategies to avoid the use of support structures with comparable dimensions to the stent struts. Process parameters were studied using an SLM system operating with pulsed wave emission to assess the geometrical fidelity and the density of thin struts. The novel stent mesh was designed and produced employing gaps with unmelted powder between the consecutive cells along the build direction. Solution annealing and stress relieving treatments were assessed after SLM. The results show that regular struts with high density (>99.5%) with an austenitic transformation finish below the room temperature can be achieved with SLM and dedicated heat treatment.

Transcervical Versus Transfemoral Approach in Carotid Stenting Real World Experience in a Community Hospital

Peri-procedural embolic events are the Achilles' heel of carotid stenting. To overcome this complication, transcervical access to the carotid artery was introduced. In this study we describe our "our life" experience with the transcervical approach in a community hospital. All carotid stent procedures between January 2010 and December 2020 were included in this retrospective analysis. The transcervical approach was compared to the transfemoral approach. In both procedures open-cell, closed-cell design and hybrid stents were used. In-hospital stroke was the primary outcome measure. A total of 340 procedures were performed, in 184 patients the transfemoral approach was used and in 156 patients the transcervical approach was used. In 12 patients (3.5%) an in-hospital stroke was diagnosed, 4 in the transfemoral group (2.2%) and 8 in the transcervical group (5.1%) (P=0.14). In the multivariate analyses a symptomatic lesion was associated with in-hospital stroke. Neither type of access nor cell design was associated with increased risk of in-hospital stroke. In contrast to previous studies, we could not confirm the advantages of the transcervical approach. However, conclusions should be carefully drawn, since this study is retrospective and was performed with multiple surgeon and different kind of stents.

Endovascular treatment for native coarctation in children in France. A multicentric, retrospective long-term analysis

Percutaneous treatment of native coarctation (coA), gold standard in adult patients, is still debated in children. We aim to report the French multicentre experience. All patients aged 1 to 18 yrs with native coA, treated percutaneously between 01/2000 and 12/2018, were included in this multcentric (9 centres) retrospective survey. One hundred and thirty three children (34 female) were included. Indication for treatment was hypertension in 109, exercise hypertension in 8 and other reasons in 16 patients. Mean age at intervention was 11.5 ± 3.9 years, mean weight 41 ± 18 kg. Procedure consisted of isolated balloon dilatation in 5 (mean age 2,63 yrs, mean weight 12 kg), balloon dilatation followed by stent implantation in 8 (mean age 11 yrs, mean weight 37 kg), and immediate stent implantation in 120 (mean age 12 yrs, mean weight 43 kg). Stents used ( n = 124/128) were covered in 43, non-covered in 77, including 38 open cell stents. Invasive gradient across coA dropped from 28 mmHg (range 5 to 64) at baseline ( n = 124) to 3 mmHg (range -5 to 20) after intervention ( n = 105). Three associated lesions were treated: 1 PDA closure, 1 aortic valvuloplasty and 1 left SVC occlusion. Serious vascular complications occurred in 8 patients (6%) (3 pseudo-aneurysms, 2 dissections, 2 stenosis and 1 occlusion) requiring surgery in 2. Reintervention was performed in 22%: 2 patients had surgery, 28 were treated percutaneously (14 balloon dilatations, 14 stent implantations). Mean follow-up reached 4.9 ± 4.7 years. At latest follow-up, 25% remained hypertensive with 15 patients (11%) on anti-hypertensive medication. MRI, CTscan or fluoroscopy imaging, are available in 52 patients during follow-up (39%). Rate of aneurysm formation, stent fracture and risks factors for reintervention or residual hypertension will be presented. Percutaneous treatment of native coarctation was safe and efficient in our french population. Close follow-up is required for longer-term results.

Outcomes of using various designs of carotid stents

It is assumed that the characteristics of stents including design of device may be predictors of adverse outcomes in carotid stenting. New stent designs enter the market and the stent manufacturers declare their ability to prevent periprocedural and postprocedural embolisms. The article provides an overview of clinical trials comparing the incidence rates of restenosis and ischemic complications in carotid artery stenting with various stent designs. In theory, the closed-cell stents and doublelayer stents are superior to the open-cell stents in preventing the postprocedural cerebral embolisms. However, the clinical significance of this phenomenon has not been proven, and the data on the effect of various carotid stent types on the stenting results remain controversial. In many cases, the choice of stent depends on the anatomy of the target vessel. The results of new randomized controlled clinical trials may clarify the clinical relevance of various stent designs.

Open-cell stent-assisted coiling for the treatment of paraclinoid aneurysms: traditional endovascular treatment is still not out of date.

Before we enter the era of flow diverter stents (FDS), the standard stent-assisted coiling technique is a well-established treatment option for routine paraclinoid aneurysms. We assess the clinical safety and efficacy of stent-assisted coiling with open-cell stent in the treatment of paraclinoid aneurysms and evaluate the association between clinical factors and follow-up aneurysm occlusion. The clinical and radiographic data of 110 consecutive patients with 122 paraclinoid aneurysms treated with open-cell stent between April 2015 and April 2019 were analyzed retrospectively at our center. We assessed the immediate and progressive occlusion rates, complications, and clinical outcome. Multivariate analysis was performed to investigate the risk factors of angiographic incomplete occlusion. Among 110 patients, stent-assisted coiling was successfully performed in all cases. Four (3.6%) thromboembolic events were reported during the procedure, which resulted in transient morbidity. Immediate angiography demonstrated complete occlusion in 64 (52.5%) aneurysms and no occlusion of ophthalmic artery. Angiographic follow-up at 6 months demonstrated an increase in the complete occlusion rate to 92.9%. No delayed in-stent stenosis was observed, and three aneurysms recurred. Clinical follow-up was completed in 102 patients (92.7%), and favorable outcomes were achieved in 101 (99%) patients at 6 months. Multivariate analysis showed that aneurysm size (p < 0.001) was associated with incomplete aneurysm occlusion at follow-up. Stent-assisted coil embolization with open-cell stents is safe and effective for the treatment of paraclinoid aneurysms and provides progressive occlusion without significant in-stent stenosis events.

Predictors of Ipsilateral New Ischemic Lesions on Diffusion-Weighted Imaging after Carotid Artery Stenting in Asymptomatic Patients: A Retrospective Observational Study with Conventional Multicontrast MRI

The purpose of this study was to identify the independent risk factors for ipsilateral new ischemic lesions (NILs) during carotid artery stenting (CAS). In patients treated with CAS, the association between postoperative ipsilateral NILs on diffusion-weighted imaging (DWI) and patient demographics, intraoperative factors, the presence of plaque components, the semiquantitative grading of component size on multicontrast magnetic resonance imaging (MRI) were retrospectively analyzed. Ipsilateral NILs on DWI were detected in 85 (39.2%) patients. The debris was observed on the surface embolic protection devices in 70.97% of patients. Univariate analysis showed that different stages of intraplaque hemorrhage (IPH) (along with lipid-rich necrotic core [LRNC]) (P < 0.001), size of IPH (P < 0.001), calcification (CA) (P = 0.045), and LRNC (without IPH) (P < 0.001) as well as postdilation (P < 0.001)), stent type (P = 0.001), and aortic arch ulcer (P = 0.004) were associated with postoperative ipsilateral NILs. Multivariate logistic regression analysis showed that the acute and recent IPH (along with LRNC) (odds ratio [OR]: 5.77, P < 0.002 and OR: 28.66, P < 0.001, respectively), LRNC size in Grade 2 (OR: 6.10, P < 0.001) were independent risk factors for ipsilateral NILs. Aortic arch ulcer (OR: 3.44, P = 0.002), postdilation (OR: 4.72, P = 0.04) and open cell stent (OR: 2.88, P < 0.016) were also significantly related to ipsilateral NILs on DWI after CAS. There was a significant correlation between IPH at different stages and their grade of size (correlation coefficient: 0.89; P < 0.001). The IPH and larger LRNC along with the aortic arch ulcer, postdilation and open cell stent are associated with increased risk of ipsilateral NILs on DWI after CAS procedure. Preoperative staging of IPH and semiquantitative grading of size of plaque components based on multi-contrast MRI may be useful for predicting ipsilateral cerebral ischemic events after CAS.

Tips for Selecting Balloons or Stents for Cerebral Aneurysms: Effective Use of Each Device

We introduce typical use cases and the appropriate use of balloon catheters and neck bridge stents for coil embolization of cerebral aneurysm. There are two types of balloon catheters: single-lumen and double-lumen catheters. They are also classified into compliant and super-compliant balloons by softness. Neck bridge stents are classified into two types: open-cell and closed-cell stents. Balloon- and stent-assisted techniques are both useful for wide-neck aneurysms. The complication rates of these methods are similar but the stent-assisted technique requires long-term administration of antiplatelets after the procedure. Both techniques have the challenge that the microcatheter is fixed during coil embolization. The semi-jailing technique, in which the stent is partially deployed during coil insertion, solves this problem. Open-cell stents seem more suitable for this technique because they fit better to the vessel wall even in the curved part. It is important to understand the characteristics of each device for safe and effective treatments.

Comparison of open- and closed-cell stent design outcomes after carotid artery stenting in the Vascular Quality Initiative

BackgroundThe association between stent design and outcomes after carotid artery stenting (CAS) has remained controversial. The available data are conflicting regarding the superiority of any specific stent design. The present study investigated the association between cell design and outcomes after carotid artery stenting (CAS) in a real world setting. MethodsPatients who had undergone CAS with distal embolic protection in the Society for Vascular Surgery Vascular Quality Initiative (VQI) database from 2016 to 2018 were included in the present study. Patients undergoing CAS for trauma or dissection or more than two treated lesions were excluded. We also excluded lesions for which more than two carotid stents had been used and lesions confined to the common or external carotid artery. Univariable and multivariable logistic regression analyses were used to compare the outcomes after CAS between the open- and closed-cell stent designs. ResultsOf the 2671 CAS procedures included in the present analysis, 1384 (51.8%) had used closed-cell stents and 1287 (48.2%) had used open-cell stents. On univariable analysis, no significant differences were noted between the closed- and open-cell stents in in-hospital mortality (1.8% vs 1.4%; P = .40), stroke (1.8% vs 2.4%; P = .28), and stroke/death (3.3% vs 3.5%; P = .81). After adjusting for potential confounders (ie, age, symptomatic status, previous major amputation, statin and antiplatelet use, American Society of Anesthesiologists class, elective procedures, approach, and post-stent dilatation), no difference was noted in in-hospital stroke/death between the two stent designs (odds ratio [OR], 1.08; 95% confidence interval [CI], 0.68-1.74; P = .74). However, the interaction between stent design (open vs closed) and lesion location (bifurcation vs internal carotid artery [ICA]) was statistically significant (P = .02). Closed-cell stents were associated with five times the odds of in-hospital stroke/death when used in carotid artery bifurcation (OR, 5.5; 95% CI, 1.3-22.2; P = .02). However, when the stent was limited to the ICA, no differences were noted (OR, 0.87; 95% CI, 0.51-1.45; P = .62). One-year follow-up data were available for 19% of patients. No differences in ipsilateral stroke or death at 1 year were noted between the open- and closed-cell stents, except when the lesion was located in the carotid bifurcation (hazard ratio, 6.7; 95% CI, 1.4-31.4; P = .02). ConclusionsClosed-cell stents were associated with an increased odds of in-hospital stroke/death for carotid bifurcation lesions, which might be related to the relatively lower conformability of closed-cell stents in the tortuous and diameter-mismatched bifurcation anatomy vs the relatively linear uniform diameter of the ICA. Improved follow-up and in-depth analysis of lesion-specific characteristics that might influence the outcomes of these two designs are needed to validate these results.

Y-Stent-Assisted Coiling With Low-Profile Neuroform Atlas Stents for Endovascular Treatment of Wide-Necked Complex Intracranial Bifurcation Aneurysms.

Y-stent-assisted coiling is one of the eligible techniques for the treatment of complex bifurcation aneurysms. In majority of previous literature, Y-stenting has been performed using stents that could be delivered through large profile microcatheters that are often difficult to manipulate during navigation through sharply angled side branches. Attempts to navigate with these large profile catheters might cause serious complications during Y-stenting procedure. To investigate the safety, feasibility, and efficacy of Y-stent-assisted coiling procedure with Neuroform Atlas stents for the treatment of complex bifurcation aneurysms; Neuroform Atlas is a recently introduced open-cell stent that can be delivered though low-profile microcatheters. We identified the patients with intracranial bifurcation aneurysms treated by Y-stent-assisted coiling procedure with Neuroform Atlas stents. We assessed the immediate postoperative and follow-up clinical and angiographic outcomes. We also investigated the periprocedural and delayed complications. A total of 30 aneurysms in 30 patients were included in the study. Y-stenting was successfully performed without any technical complications in all cases (100%). Immediate postprocedural angiography revealed total aneurysm occlusion in 83.3% of patients. The mean angiographic follow-up time was 11.8 mo. The last follow-ups showed complete occlusion in 93.3% of patients. There was no mortality in this study. A procedure-related complication developed in 6.7% and resulted in permanent morbidity in 3.3% of patients. Neuroform Atlas stent combines the advantages of low-profile deployment microcatheters with an open-cell structure to achieve a successful Y-stenting procedure. Y-stent-assisted coiling with Neuroform Atlas stents provides a safe and effective endovascular treatment for wide-necked complex bifurcation aneurysms.

Early Multicenter Experience With the Neuroform Atlas Stent: Feasibility, Safety, and Efficacy.

The Neuroform Atlas stent™ (by Stryker, Fremont, California) represents the most recent widely available upgrade to intracranial stenting, providing a laser cut open cell stent with a diameter of 3.0 to 4.5 mm that is delivered through an 0.017-inch microcatheter. To report our initial multicenter experience of the safety, efficacy, and feasibility of the Atlas stent used for treating aneurysms, as well as one case of intracranial stenosis and one carotid artery dissection as well as other pathologies. A retrospective multicenter study of subjects treated with Atlas stent during the period 2018 to 2019. The total number of patients included in our analysis was 71 patients. The stent was utilized to treat 69 aneurysm cases. Of the aneurysms, 36% presented with acute rupture and 56% of the ruptured aneurysms were high grade. Mean aneurysm dimension was 7 mm with an average neck width of 4.1 mm. Around 30% had received prior treatment. Telescoping or Y-stent was used in 16% of cases. We did not observe any symptomatic major complications in our series. Asymptomatic major complications were seen in 7 patients (10.1%); technical complications occurred in 4.3%. Immediate modified Raymond-Roy-occlusion-outcome class I/II was observed in 87%, and this increased to 97.7% at latest follow-up, which was at 4 mo; 91.8% of patients achieved favorable clinical outcome, and mortality rate was 1.4%. Our series demonstrates the safety, feasibility, and efficacy of the Atlas stent. The low complication rate and the high obliteration rate managing complex aneurysms, even in an acute ruptured setting, are notable.