Enterprise stent for the treatment of symptomatic intracranial atherosclerotic stenosis: an initial experience of 44 patients

Short-term outcome of stenting with Enterprise stents for symptomatic intracranial atherosclerotic disease at a single center

OBJECTIVE

To evaluate the safety and efficacy of stenting for symptomatic intracranial atherosclerotic severe stenosis or occlusion with Enterprise stents.

METHODS

Fifty-three consecutive patients with symptomatic intracranial atherosclerotic severe (70%-99%) stenosis or occlusion who underwent endovascular treatment with Enterprise stents between September 2019 and March 2022 were retrospectively analyzed. Primary outcomes included technical stenting success rates, the incidence of complications within 30 days of the procedure, and the in-stent restenosis rates during the follow-up period. These outcomes were further categorized based on lesion location and operation time.

RESULTS

Fifty-seven lesions in 53 patients aged 61.0 ± 10.0 years were treated with Enterprise stents with a technical success rate of 100%. Seven patients (12.3%) had severe complications within 30 days of the procedure: five had a symptomatic ischemic stroke, one had a symptomatic intracerebral hemorrhage, and one had a subarachnoid hemorrhage related to the procedure. No deaths were observed. The rate of in-stent restenosis was 18.2%, with a mean vascular imaging follow-up period of 6.7 months. The 30-day complication and in-stent restenosis rates did not differ significantly between patients with different lesion locations and operation times (P > 0.05).

CONCLUSION

This retrospective study suggests that percutaneous transluminal angioplasty and stenting with Enterprise stents is an effective treatment for symptomatic intracranial arterial stenosis or occlusion with a high technical success rate. It also indicates that stenting during the early nonacute stage after stroke may not increase the incidence of perioperative complications for symptomatic intracranial atherosclerotic stenosis when following strict inclusion criteria.

Safety and efficacy of the Low-Profile Visualized Intraluminal Support stent in treating intracranial atherosclerotic stenosis

PURPOSE

The performance of the Low-Profile Visualized Intraluminal Support (LVIS) stent deployed following balloon angioplasty is unknown in treating intracranial atherosclerotic stenosis, and this study was to investigate the safety and efficacy of the LVIS stent in treating intracranial atherosclerotic stenosis in the middle cerebral artery M1 segment.

METHODS

Thirty-five patients were enrolled with 35 atherosclerotic stenoses at the M1 segment. The stenosis was about 75% in 16 patients, 80% in 15, and 90% in the rest four. The LVIS stent was used to treat these patients.

RESULTS

The success rate of stenting was 97.1%. The stenting procedure was failed in one patient because of intraprocedural dissection of the stenotic (75%) segment, resulting in a 30-day periprocedural complication rate of 2.9% (1/35). Before stenting, the stenosis rate ranged 75%-90% (mean 78.9%±4.7%), and after stenting, the diameter of the stented segment was significantly (P<0.0001) increased to 1.5-3.4mm (mean 2.1±0.32mm) ranging 68.2%-100% (mean 94.0%±5.8%) of the normal arterial diameter, with the residual stenosis ranging 0-31.8% (median 4.8%, IQR 2.4%-7.3%). Follow-up was performed at 6-20 months (mean 8.5) after stenting. One patient (2.9%) had occlusion of the stented M1 segment with no symptoms, and two patients (5.7%) had slight asymptomatic instent stenosis (40%) at the M1 segment, with the instent restenosis and occlusion rate of 8.6% (3/35).

CONCLUSION

The braided LVIS stent can be safely applied for treatment of intracranial atherosclerotic stenosis in the middle cerebral artery with good safety and efficacy immediately after stenting and at follow-up.

Novel technique of stent placement via gateway balloon in intracranial atherosclerosis-associated large vessel occlusion

BACKGROUND AND PURPOSE

Neuroform Atlas stent can be deployed directly via gateway balloon for angioplasty and stent placement without the need for exchange maneuver required for Wingspan stent use. We present our initial experience of this strategy in intracranial atherosclerosis-associated large vessel occlusions.

METHODS

Patients were identified through mechanical thrombectomy (MT) database from January 2020 to June 2022 at our institutions. Due to reocclusion or impending occlusion, rescue angioplasty with stent placement was performed after initial standard MT. Primary outcomes were good angiographic recanalization with modified thrombolysis in cerebral infarction (mTICI) score of 2b-3, rate of intracranial hemorrhage (ICH), and favorable functional outcome at 3 months, that is, modified Rankin Scale (mRS) score of 0-3.

RESULTS

We identified 22 patients treated using this technique. Among those, 11 were females with their average age at 66 years (range: 52-85). Initial median National Institute of Health Stroke Scale score was 11 (range: 5-30) and all patients received loading doses of aspirin and P2Y₁₂ inhibitor. After performing submaximal angioplasty and Neuroform Atlas stent deployment through the gateway balloon, we achieved final mTICI of 2b-3 in 20 (90%) patients. One patient had ICH post-op that was asymptomatic. Eight (36%) patients had mRS of 0-3 at 90 days.

CONCLUSION

Our preliminary experience suggests possible safety and feasibility of deploying Neuroform Atlas stent through a compatible Gateway balloon microcatheter without the need for ICH-associated microcatheter exchange. Further studies with long-term clinical and angiographic follow-up are warranted to corroborate our initial findings.

Safety and efficacy of enterprise stenting for symptomatic atherosclerotic severe posterior circulation stenosis

PURPOSE

To investigate the safety and efficacy of Enterprise stent angioplasty and risk factors for the prognoses in treating symptomatic severe posterior circulation atherosclerotic stenosis (SSPCAS).

MATERIALS AND METHODS

Patients with SSPCAS who were treated with the Enterprise stent angioplasty were retrospectively enrolled. The clinical data, peri-procedural complications, postoperative residual stenosis, in-stent restenosis and recurrent stroke at follow-up were analyzed.

RESULTS

262 patients with 275 stenotic lesions treated with the Enterprise stent angioplasty were enrolled. The stenosis degree was reduced from 86.3 ± 6.2% before to 19.3 ± 5.4% after stenting. Complications occurred in 14 (5.3%) patients. Clinical follow-up was performed in 245 (93.51%) patients for 16.5 ± 7.3 months. During 1 year follow-up, 7 patients (2.9%) had recurrent symptoms, including 4 patients with stenting in the intracranial vertebral artery and 3 in the basilar artery. Imaging follow-up was conducted in 223 (85.11%) patients. In-stent restenosis was present in 35 patients (15.7%), with the restenosis rate of 26.4% (n = 23) in the intracranial vertebral artery, which was significantly (P < 0.001) greater than in the basilar artery (8.8%). Six patients (17.1%) with in-stent restenosis were symptomatic. The stenotic length was the only significant (P = 0.026 and 0.024, respectively) independent risk factor for 1 year stroke or death events and in-stent restenosis.

CONCLUSION

The Enterprise stent can be safely and efficaciously applied in the treatment of symptomatic severe posterior circulation atherosclerotic stenosis, with a relatively low rate of in-stent restenosis and recurrent stroke within 1 year. The stenotic length was the only significant independent risk factor for 1 year stroke or death events and in-stent restenosis.

Identifying risk factors for in-stent restenosis in symptomatic intracranial atherosclerotic stenosis: a systematic review and meta-analysis

Background

In-stent restenosis (ISR) is an adverse and notable event in the treatment of intracranial atherosclerotic stenosis (ICAS) with percutaneous transluminal angioplasty and stenting (PTAS). The incidence and contributing factors have not been fully defined. This study was performed to evaluate factors associated with ISR after PTAS.

Data source

We identified studies on ISR after PTAS from an electronic search of articles in PubMed, Ovid MEDLINE, and the Cochrane Central Database (dated up to July 2022).

Results

A total of 19 studies, including 452 cases of ISR after 2,047 PTAS, were included in the meta-analysis. The pooled incidence rate of in-stent restenosis was 22.08%. ISR was more likely to occur in patients with coronary artery disease (OR = 1.686; 95% CI: 1.242-2.288; p = 0.0008), dissection (OR = 6.293; 95% CI: 3.883-10.197; p < 0.0001), and higher residual stenosis (WMD = 3.227; 95% CI: 0.142-6.311; p = 0.0404). Patients treated with Wingspan stents had a significantly higher ISR rate than those treated with Enterprise stents (29.78% vs. 14.83%; p < 0.0001).

Conclusions

The present study provides the current estimates of the robust effects of some risk factors for in-stent restenosis in intracranial atherosclerotic stenosis. The Enterprise stent had advantages compared with the Wingspan stent for ISR. The significant risk factors for ISR were coronary artery disease, dissection, and high residual stenosis. Local anesthesia was a suspected factor associated with ISR.

Optional or optimal? off-label stenting for intracranial atherosclerotic stenosis: A scoping review

BACKGROUND

Intracranial atherosclerotic stenosis is a major cause of ischemic stroke. In addition to the Wingspan stent system, several self-expanding stents have been used off-label to treat intracranial atherosclerotic stenosis lesions. The purpose of this review is to assess the existing data on the off-label use of self-expanding stents in intracranial atherosclerotic stenosis, to highlight methodological limitations in current study designs, and thus providing strategies and precautions for clinical practice.

METHODS

The PubMed, EMBASE, and the Cochrane Library databases were systematically searched for relevant articles published up to April 2022. In addition to the meta analysis of Enterprise, Neuroform EZ and closed cell stent respectively, we used a narrative synthesis to summarize and discuss the appropriate strategies and precautions for the use of each stent.

RESULTS

We identified 17 studies (1091 patients with 1124 lesions) reporting 6 types of off-label self-expanding stents. The most common endpoints reported were incidence of short-term complications (range: 0-15.8%, median: 3.8%), long-term complications (range: 0-12.0%, median: 0%). Potential risks include infeasibility of stenting hard lesions or tortuous vessels, stent migration, and in-stent thrombosis. Less is known about the conditions that are appropriate for an optimal stent (e.g., open-cell, close-cell, hybrid cell). There was considerable heterogeneity across studies with regards to study populations and study designs.

CONCLUSIONS

The potential risks and benefits should be carefully considered when using off-label stents for intracranial atherosclerotic stenosis, particularly given the current evidence power. As a potential option for the Wingspan stent, based on device's approval only, a tailored approach with lesion-specific devices could be beneficial in certain patients.

Anterior cerebral artery dissection for a patient with ipsilateral aplastic or twig-like middle cerebral artery: An illustrative case report

Background

An aplastic or twig-like middle cerebral artery (Ap/T-MCA) is a rare anomaly, which sometimes causes ischemic infarction. Collateral flow from the ipsilateral anterior cerebral artery (ACA) is important for patients with Ap/T-MCA. If ipsilateral ACA stenosis or occlusion occurs, a large infarction with a wider field than the ACA territory could happen. First, mechanical thrombectomy was performed for the right ACA near occlusion caused by arterial dissection with ipsilateral Ap/T-MCA in this case. Second, Wingspan stenting was performed for the right ACA restenosis.

Case Description

A 77-year-old female presented to the hospital with the left hemiparesis. We diagnosed a right ACA infarction caused by right ACA occlusion. Digital subtraction angiography showed right Ap/T-MCA and ipsilateral ACA near occlusion. Thrombectomy was performed, and recanalization was achieved with mild ACA stenosis. The lesion was the dissection due to angiographical finding. Two months after treatment, transient left hemiparesis occurred and right ACA stenosis progressed. Computed tomography perfusion showed hypoperfusion of the right hemisphere. Wingspan stenting was performed from the left internal carotid artery through the anterior communicating artery with an intermediate catheter. The patient was discharged without any neurological deficit.

Conclusion

We reported the first case of a patient who underwent Wingspan stenting for the right ACA dissection with Ap/T-MCA. Short-term follow-up and aggressive intervention should be considered for collateral pathway dissection with Ap/T-MCA because the symptoms can become serious. The patients with Ap/T-MCA should be cautious about the collateral pathway arterial changes in particular ipsilateral ACA due to the increasing hemodynamic stress.

The effectiveness of enterprise stent use on the treatment of intracranial atherosclerosis disease

OBJECTIVE

To examine the clinical outcome of Enterprise stent in patients with severe and symptomatic intracranial atherosclerosis.

MATERIAL AND METHOD

Twenty-five patients who underwent Enterprise stenting between January 2012 and March 2019 were included in this study. Exclusion criteria were previous intracranial stenting and inadequate follow-up. Technical success rates of the procedures were recorded. Clinical outcome was evaluated with pre- and post-treatment modified Rankin Scale scores. The patients were monitored for 18 months clinically and for 14.3 months radiologically.

RESULTS

The mean age of the 15 males and 10 females was 61.6 ± 8.19. Of these 25 patients, 6 (24%) were in the anterior system and 19 (76%) were in posterior system. The mean degree of pre-treatment stenosis was 86.4% ± 7 with the mean lesion length of 12.5 ± 7.5 mm. The residual stenosis rate was 23.8% ± 8.81. Technical success rate was 100%. There were two major complications within the first 30 days (8%). Late major complications (after 30 days) occurred in one case (4%). Stent restenosis was detected in two patients (8%). No intracranial bleeding or mortality was observed.

CONCLUSION

In this single-center study, we achieved high technical success and tolerable complication rates. Enterprise stent may be a good treatment alternative for severe intracranial stenosis especially in patients resistant to medical treatment when correct patient selection is made. However, further randomized controlled studies, including more cases should be carried out.

Sub-satisfactory recanalization of severe middle cerebral artery stenoses can significantly improve hemodynamics

Purpose

To investigate the effect of sub-satisfactory stent recanalization on hemodynamic stresses for severe stenoses of the middle cerebral artery (MCA) M 1 segment.

Materials and methods

Patients with severe stenoses of the MCA M1 segment treated with endovascular stent angioplasty were retrospectively enrolled. Three-dimensional digital subtraction angiography before and after stenting was performed; the computational fluid dynamics (CFD) analysis of hemodynamic stresses at the stenosis and normal segments proximal and distal to the stenoses was analyzed.

Results

Fifty-one patients with severe stenosis at the MCA M1 segment were enrolled, with the stenosis length ranging from 5.1 to 12.8 mm (mean 9 ± 3.3 mm). Stent angioplasty was successful in all (100%) the patients. The angiography immediately after stenting demonstrated a significant (P &lt; 0.05) decrease in MCA stenosis after comparison with before stenting (31.4 ±12.5% vs. 87.5 ± 9.6%), with residual stenosis of 15–30% (mean 22.4 ± 3.5%). Before stenting, the total pressure was significantly higher (P &lt; 0.0001), while the WSS, velocity, and vorticity were all significantly decreased (P &lt; 0.0001) at the normal arterial segment proximal to the stenosis, and the total pressure, WSS, velocity, and vorticity were all significantly decreased (P &lt; 0.0001) at the normal arterial segment distal to the stenosis compared with those at the stenosis. After sub-satisfactory stenting recanalization, all the hemodynamic stresses proximal or distal to the stenosis and at the perforator root were improved compared with those before stenting and were similar to those after virtual stenosis removal.

Conclusion

Sub-satisfactory recanalization of severe MCA stenoses can significantly improve the hemodynamic status for cerebral perfusion at the stenoses.

Hemodynamic and Geometric Risk Factors for In-Stent Restenosis in Patients with Intracranial Atherosclerotic Stenosis

Methods

Severe ICAS patients managed with percutaneous transluminal angioplasty and stenting (PTAS) were included in the retrospective cohort study and were divided into two groups according to whether ISR occurred at follow-up (ISR group and no-ISR group). Computational fluid dynamics models were built based on digital subtraction angiography before and after PTAS to simulate blood flow and quantify hemodynamic parameters. The associations between vessel geometry, hemodynamics, and ISR in ICAS patients were investigated.

Results

Among 39 patients, ISR occurred in seven patients (17.95%) after a mean follow-up period of 6.69 ± 3.24 months. Stenting decreased vessel angulation (51.11° [40.07°-67.27°] vs. 15.97° [0.00°-36.16°], P = 0.000) and vessel tortuosity (0.09 [0.06-0.13] vs. 0.01 [0.00-0.03], P = 0.000). Meanwhile, the translational pressure ratio (PR) dramatically increased (0.07 [0.00-0.31] vs. 0.62 [0.41-0.82], P = 0.000) with the wall shear stress ratio decreased (13.93 [8.37-40.30] vs. 2.90 [1.69-4.48], P = 0.000). In the multivariate analysis, smaller Δ tortuosity (P = 0.038) was independently associated with the occurrence of ISR, and smaller post-PTAS translesional PR was also a predictive factor of marginal significance (P = 0.059).

Conclusion

PTAS decreased vessel angulation, vessel tortuosity, and translesional wall shear stress ratio while it increased translesional pressure ratio (PR) dramatically in ICAS patients. Smaller Δ tortuosity was found to be a risk factor for ISR, and smaller post-PTAS translesional PR was also a predictive factor of marginal significance, indicating that both geometric and hemodynamic parameters played important roles in the occurrence of ISR after PTAS.

Endovascular Treatment of Large Vessel Occlusion Strokes Due to Intracranial Atherosclerotic Disease

Mechanical thrombectomy (MT) has become the gold-standard for patients with acute large vessel occlusion strokes (LVOS). MT is highly effective in the treatment of embolic occlusions; however, underlying intracranial atherosclerotic disease (ICAD) represents a therapeutic challenge, often requiring pharmacological and/or mechanical rescue treatment. Glycoprotein IIb/IIIa inhibitors have been suggested as the best initial approach, if reperfusion can be achieved after thrombectomy, with angioplasty and/or stenting being reserved for the more refractory cases. In this review, we focus on the therapeutic considerations surrounding the endovascular treatment of ICAD-related acute LVOS.

The safety and efficacy of the Neuroform EZ stent for the treatment of symptomatic atherosclerotic stenosis in the middle cerebral artery

OBJECTIVE

To evaluate the safety and efficacy of Neuroform EZ stent placement for patients with symptomatic atherosclerotic stenosis of the middle cerebral artery (MCA).

METHOD

We retrospectively reviewed the clinical data of 70 patients (36 males and 34 females; mean age: 62.5 ± 1.25 years) with symptomatic atherosclerotic stenosis of the MCA who underwent Neuroform EZ stent insertion between January 2018 and June 2020. We reviewed the clinical data of each patient so that we could evaluate outcomes and angiographic findings at follow-up.

RESULTS

The technical success rate for the 70 patients was 100%. The mean rate of stenosis improved from 82.6 ± 6.5% (pre-stenting) to 21.11 ± 2.6% (post-stenting). During the post-stenting follow-up period, the 1-year frequencies of stroke, transient ischemic attack, and death, were all 0%. 42 patients were reviewed in hospital by DSA or CTA. Of the patients undergoing DSA or CTA review, four patients were found to have in-stent restenosis.

CONCLUSION

Our analysis indicates that the Neuroform EZ stent represents a valuable endovascular treatment option for patients with severe stenosis of the MCA. Additional studies are now needed to evaluate the long-term outcomes arising from the use of this technique.

Application of High-Resolution Flat Detector Computed Tomography in Stent Implantation for Intracranial Atherosclerotic Stenosis

Objective

To evaluate the utility of high-resolution flat-detector computed tomography (HR-FDCT) compared with conventional flat-detector computed tomography (FDCT) for stent placement in symptomatic intracranial atherosclerotic stenosis (ICAS).

Methods

We retrospectively reviewed the clinical data of 116 patients with symptomatic ICAS who underwent stent implantation. Images were acquired using conventional FDCT [voxel size = 0.43 mm (isotropic)] and HR-FDCT [voxel size = 0.15 mm (isotropic)]. Immediately after stent deployment, dual-volume three-dimensional (3D) fusion images were obtained from 3D digital subtraction angiography (DSA) and HR-FDCT. The image quality for stent visualization was graded from 0 to 2 (0: not able to assess; 1: limited, but able to assess; 2: clear visualization), and the stent-expansion status (“full,” “under-expanded” or “poor apposition”) was recorded.

Results

A total of 116 patients with symptomatic ICAS were treated successfully using 116 stents (58 Neuroform^TM EZ, 42 Enterprise^TM, and 16 Apollo^TM). The mean pre-stent stenosis was 80.5 ± 6.4%, which improved to 20.8 ± 6.9% after stenting. Compared with FDCT, HR-FDCT improved visualization of the fine structures of the stent to improve the image quality that significantly (mean score: 1.63 ± 0.60 vs. 0.41 ± 0.59, P < 0.001). In 19 patients, stent under-expansion (n = 11) or poor apposition (n = 8) was identified by HR-FDCT but not by conventional FDCT. After balloon dilatation, stent malapposition was shown to have improved on HR-FDCT. None of the 19 patients with stent malapposition experienced short-term complications during hospitalization or had in-stent stenosis at 6-month follow-up.

Conclusion

High-resolution flat-detector computed tomography (HR-FDCT) improves visualization of the fine structures of intracranial stents deployed for symptomatic ICAS compared with that visualized using conventional FDCT. High-resolution flat-detector computed tomography improves assessment of stent deployment and could reduce the risk of complications.

Long-Term Outcome of Enterprise Stenting for Symptomatic ICAS in a High-Volume Stroke Center

Background and Purpose: The Enterprise stent has been used for treating intracranial atherosclerotic stenosis (ICAS), but its long-term outcome remains unclear. The purpose of this study was to evaluate the long-term clinical efficacy of the Enterprise stent used for patients with symptomatic ICAS due to hypoperfusion.

Method: Patients with symptomatic ICAS due to hypoperfusion treated with the Enterprise stents from a high-volume stroke center were evaluated. The successful recanalization was defined as the Modified Thrombolysis In Cerebral Infarction (mTICI) ≥ 2b. The stroke and neurological death that occurred within 72 h after the procedure as well as long-term clinical and imaging outcomes were analyzed.

Results: Overall, 130 patients with 130 ICAS treated with the Enterprise stent were included in our study. The successful recanalization rate was 100%. The mean pre- and postprocedural stenosis was 82.9 ± 8.9% vs. 15.1 ± 8.4%. Periprocedural complications occurred in 5 (3.8%) patients within 72 h after the procedure. Clinical follow-up data were available in 125 (96.2%) patients (median, 24 months) and any stroke or neurological death was encountered in 6 (4.8%) patients. Angiographic follow-up data was obtained from 118 (90.8%) patients (median, 13.5 months). In addition, 1-year in-stent restenosis (>70%) was found in 17 (14.4%) patients, and among them, 4 (23.5%) patients were symptomatic.

Conclusion: Deployment of Enterprise stent is safe for ICAS. The short-term and long-term outcomes were acceptable, but the efficacy of the Enterprise stent needs to be further evaluated in future studies.

Endovascular treatment of symptomatic intracranial atherosclerotic stenosis with low profile visualized intraluminal support stent

OBJECTIVE

Severe intracranial atherosclerotic stenosis has become one of the main causes resulting transient ischemic attack and stroke. This study aimed to evaluate the efficacy and safety of low profile visualized intraluminal support (LVIS) stent in treating symptomatic intracranial atherosclerotic stenosis.

METHODS

Data of 31 patients with at least 70% stenosis treated with LVIS stent in our center were retrospectively collected between July 2017 and November 2020. Further evaluation of lesion characteristics, technical success rate, preoperative complication, clinical and angiographic follow-up outcome, delayed in-stent stenosis were conducted.

RESULTS

Stent delivery and deployment were successfully achieved in all 31 patients (100%). 22 cases (71%) were located in anterior circulation and 9 cases (29%) were located in posterior circulation. The mean degree of stenosis lesion before stent deployment was 85.6 ± 9.4%, while after stenting was 11.2 ± 11.8%. One patient suffered from ischemic complication in stenting procedure, and timely delivery of rt-PA successfully recanalized the artery. Clinical follow-up was available in all 31patients (100%) with mean follow-up time 15.0 ± 12.1(3-45) months. No patients experienced the recurrence of stroke or TIA or death after discharge. Angiographic follow-up was available in 21patients (67.7%) with mean follow-up time 11.43 ± 6.8 (6-36) months. 19 patients (90.5%) were stable while 2 patients (9.5%) developed ISR in their last angiographic follow-up. The 2 patients received balloon angioplasty and reached satisfactory results after retreatment.

CONCLUSION

This preliminary study suggests that LVIS stent deployment was a feasible approach in treating intracranial atherosclerotic stenosis with satisfactory procedure success rate, low complication rate and favorable long-term outcome.

A Comparison of Safety and Effectiveness Between Wingspan and Neuroform Stents in Patients With Middle Cerebral Artery Stenosis

Background: Percutaneous transluminal angioplasty and stenting with the Wingspan stent has proven safe and effective in patients with middle cerebral artery stenosis (MCAS), but the off-label use of the Neuroform stent might be an alternative treatment. This study aimed to compare the safety and effectiveness of the above two intracranial stents in patients with MCAS. Methods: We retrospectively analyzed consecutive patients with symptomatic MCAS who had been treated with the Neuroform EZ or the Wingspan stent. A propensity score was generated to control for differences in baseline characteristics. The endpoints were the rate of peri-procedural complications within 30 days after stenting, the in-stent restenosis rate, and any target-vessel-related stroke or deaths during follow-up. Results: After matching for propensity score, the peri-procedural complication rate in the Wingspan group was 7.4% compared with 5.6% in the Neuroform group (p = 1.00), while the follow-up in-stent restenosis rates were 23.3 vs. 14.3%, respectively (p = 0.41). In the restenosis group, the patients tended to be younger (p < 0.01) and the degree of artery stenosis before stenting was higher (p < 0.01). Conclusion: This study indicated that in patients with symptomatic MCAS, Neuroform EZ stents are an alternative to Wingspan. Moreover, younger age and higher degree of artery stenosis before stenting might be a risk factor of in-stent restenosis.

Factors affecting in-stent restenosis after angioplasty with the Enterprise stent for intracranial atherosclerotic diseases

This study investigated factors affecting the safety and in-stent restenosis after intracranial stent angioplasty using the Enterprise stent for symptomatic intracranial atherosclerotic stenosis. Between January 2017 and March 2019, patients with intracranial atherosclerotic stenosis treated with Enterprise stent angioplasty were enrolled, including 400 patients in the modeling group and 89 patients in the validation group. The clinical factors affecting in-stent restenosis after Enterprise stent angioplasty in the modeling group were analyzed, and a logistic regression model of these factors was established and validated in the validation group. The receiver operating characteristic (ROC) curve and the area under the ROC curve (AUC) were analyzed. In the modeling group with 400 patients, there were 410 lesions, including 360 stenotic lesions and 50 occluded lesions, with 176 (42.9%) lesions in the anterior circulation and 234 (57.1%) in the posterior circulation. Successful stenting was performed in 398 patients (99.5%). Stenosis was significantly (P < 0.05) improved after stenting compared with before stenting (27.7% ± 2.9% vs. 77.9% ± 8.0%). Periprocedural complications included ischemic stroke (3.25%), hemorrhagic stroke (0.75%), and death (0.50%), with a total periprocedural complication rate of 4.0%. The first follow-up angiography was performed in 348 (87.0%) patients with 359 lesions 3.5-14 months (mean 5.7 months) after stenting. In-stent restenosis occurred in 62 (17.3%) lesions, while the other 295 (82.7%) had no restenosis. Lesion location, calcification degree, balloon expansion pressure, residual stenosis, intraprocedural dissection, and cerebral blood flow TICI grade were significant (P < 0.05) risk factors for in-stent restenosis. The in-stent restenosis prediction model was established as follows: P = 1/[1 + e^{-(-6.070-1.391 location + 2.745 calcification + 4.117 balloon inflation pressure + 2.195 intraprocedural dissection + 1.163 residual stenosis + 1.174 flow TC grade)}]. In the validation group, the AUC in the ROC curve analysis was 0.902 (95% CI: 0.836-0.969), and when the cutoff value was 0.50, the sensitivity and specificity of this model were shown to be 76.92% and 80.26%, respectively, in predicting in-stent restenosis at angiographic follow-up, with a total coincidence rate of 79.78%. In conclusion, in-stent restenosis after intracranial Enterprise stenting is affected by stenosis location, calcification, balloon inflation pressure, intraprocedural arterial dissection, residual stenosis, and cerebral flow grade, and establishment of a logistic model with these factors can effectively predict in-stent restenosis.

Safety and efficacy of the Low-Profile Visualized Intraluminal Support stent in treating intracranial atherosclerotic stenosis

PURPOSE

The performance of the Low-Profile Visualized Intraluminal Support (LVIS) stent deployed following balloon angioplasty is unknown in treating intracranial atherosclerotic stenosis, and this study was to investigate the safety and efficacy of the LVIS stent in treating intracranial atherosclerotic stenosis in the middle cerebral artery M1 segment.

METHODS

Thirty-five patients were enrolled with 35 atherosclerotic stenoses at the M1 segment. The stenosis was about 75% in 16 patients, 80% in 15, and 90% in the rest four. The LVIS stent was used to treat these patients.

RESULTS

The success rate of stenting was 97.1%. The stenting procedure was failed in one patient because of intraprocedural dissection of the stenotic (75%) segment, resulting in a 30-day periprocedural complication rate of 2.9% (1/35). Before stenting, the stenosis rate ranged 75%-90% (mean 78.9%±4.7%), and after stenting, the diameter of the stented segment was significantly (P<0.0001) increased to 1.5-3.4mm (mean 2.1±0.32mm) ranging 68.2%-100% (mean 94.0%±5.8%) of the normal arterial diameter, with the residual stenosis ranging 0-31.8% (median 4.8%, IQR 2.4%-7.3%). Follow-up was performed at 6-20 months (mean 8.5) after stenting. One patient (2.9%) had occlusion of the stented M1 segment with no symptoms, and two patients (5.7%) had slight asymptomatic instent stenosis (40%) at the M1 segment, with the instent restenosis and occlusion rate of 8.6% (3/35).

CONCLUSION

The braided LVIS stent can be safely applied for treatment of intracranial atherosclerotic stenosis in the middle cerebral artery with good safety and efficacy immediately after stenting and at follow-up.

Intracranial Angioplasty with Enterprise Stent for Intracranial Atherosclerotic Stenosis: A Single-Center Experience and a Systematic Review

Background

The high rate of periprocedural complications for the endovascular stent procedure in the Stenting Versus Aggressive Medical Management Therapy for Intracranial Arterial Stenosis (SAMMPRIS) trial resulted in it being less recommended than medical therapy to treat intracranial atherosclerotic stenosis (ICAS). Because Enterprise stent use might reduce the incidence of complications in ICAS treatment compared to other frequently used stents, this paper evaluated the safety and effectiveness of the Enterprise stent for the treatment of ICAS.

Methods

We performed a comprehensive literature search for reports on intracranial angioplasty using the Enterprise stent for ICAS treatment from the earliest date available from each database to May 2020 for PubMed, EMBASE, Web of Science, Cochrane, and Clinical Trials databases. We also reviewed the single-center experience of the First Affiliated Hospital of Harbin Medical University. We extracted information regarding periprocedural complications, procedure-related morbidity, mortality, immediate angiographic outcome, and long-term clinical and angiographic outcomes, among others. Event rates were pooled across studies using random-effects or fixed-effects models depending on the heterogeneity.

Results

Five hundred fifty-seven patients with 588 lesions from seven studies, including the institutional series, were included in the analysis. The incidence of stroke or death within 30 days was 7.4% (95% confidence interval (CI), 5.5%-10.1%). The incidence of ischemic stroke or TIA in the territory of the qualifying artery beyond 30 days and during follow-up was 3.2% (95% CI, 1.1%-9.5%). The incidence of in-stent restenosis was 10.1% (95% CI, 4.6%-22.2%), and the incidence of symptomatic restenosis was 4.1% (95% CI, 1.7%-9.9%).

Conclusions

Intracranial angioplasty utilizing the Enterprise stent for ICAS treatment was relatively safe and effective but required further verification using additional sources for evidence.

A novel technique for stenting of intracranial stenosis using the Neuroform Atlas stent and Gateway balloon catheter

Management of intracranial stenosis remains controversial. Stenting for intracranial stenosis has been associated with high complication and restenosis rates. Morbidity may be related to the intracranial microcatheter exchange that is required in stent placement after the angioplasty. We present a technique in which we deploy an Neuroform Atlas stent through the lumen of a Gateway balloon microcatheter in order to avoid intracranial microcatheter exchange and the associated morbidity. We discuss advantages and pitfalls of this novel technique.

Preliminary Experience of Neuroform Atlas Stenting as a Rescue Treatment after Failure of Mechanical Thrombectomy Caused by Residual Intracranial Atherosclerotic Stenosis

Objective

The low-profile Neuroform Atlas stent can be deployed directly without an exchange maneuver by navigating into the Gateway balloon. This retrospective study assessed the safety and efficacy of Neuroform Atlas stenting as a rescue treatment after failure of mechanical thrombetomy (MT) for large artery occlusion.

Methods

Between June 2018 and December 2019, a total of 31 patients underwent Neuroform Atlas stenting with prior Gateway balloon angioplasty after failure of conventional MT caused by residual intracranial atherosclerotic stenosis (ICAS). Primary outcomes were successful recanalization and patency of the vessel 24 hours after intervention. Secondary outcomes were vessel patency after 14 days and 3-month modified Rankin Scale. Peri-procedural complications, intracerebral hemorrhage (ICH), and 3-month mortality were reviewed.

Results

With a 100% of successful recanalization, median value of stenosis was reduced from 79.0% to 23.5%. Twenty-eight patients (90.3%) showed tolerable vessel patency after 14 days. New infarctions occurred in three patients (9.7%) over a period of 14 days; two patient (6.5%) underwent stent occlusion at 24 hours, and the other patient (3.2%) with delayed stent occlusion had a non-symptomatic dot infarct. There were no peri-procedural complications. Two patients (6.5%) developed an ICH immediately after the procedure with one of them is symptomatic.

Conclusion

Neuroform Atlas stenting seems to be an effective and safe rescue treatment modality for failed MT with residual ICAS, by its high successful recanalization rate with tolerable patency, and low peri-procedural complication rate. Further multicenter and randomized controlled trials are needed to confirm our findings.

Long-Term Risk Factors for Intracranial In-Stent Restenosis From a Multicenter Trial of Stenting for Symptomatic Intracranial Artery Stenosis Registry in China

Background: For patients with symptomatic intracranial artery stenosis (sICAS), endovascular treatment has been shown to be feasible and safe in recent studies. However, in-stent restenosis (ISR) risks the recurrence of ischemic stroke. We attempt to elucidate the risk factors for ISR. Methods: We retrospectively analyzed 97 patients with sICAS from a prospective registry trial that included 20 centers from September 2013 to January 2015. Cases were classified into the ISR≥ 50% group or the ISR < 50% group. The baseline characteristics and long-term follow-up were compared between the two groups. Binary logistic regression analyses were identified as an association between ISR and endovascular technique factors. Results: According to whether ISR was detected by CT angiography, 97 patients were divided into the ISR group (n = 24) and the non-ISR group (n = 73). The admission baseline features and lesion angiography characteristics were similar, while plasma hs-CRP (mg/L) was higher in the ISR≥ 50% group at admission (8.2 ± 11.4 vs. 2.8 ± 4.1, p = 0.032). Binary logistic regression analysis identified the longer stents (adjusted OR 0.816, 95% CI 0.699-0.953; p = 0.010), balloon-mounted stents (adjusted OR 5.748, 95% CI 1.533-21.546; p = 0.009), and local anesthesia (adjusted OR 6.000, 95% CI 1.693-21.262; p = 0.006) as predictors of ISR at the 1-year follow-up. Conclusions: The longer stents, balloon-mounted stents implanted in the intracranial vertebral or basilar artery, and local anesthesia were significantly associated with in-stent restenosis. Further studies are required to identify accurate biomarkers or image markers associated with ISR in ICAS patients. Clinical Trial Registration: www.ClinicalTrials.gov, identifier: NCT01968122.

The Enterprise2 Stent for Endovascular Treatment of Intracranial Aneurysms: Short-Term Results From a Single Center Experience

Background: Self-expanding devices, such as the Enterprise VRD (EP-VRD) have widely used for stent-assisted coiling treatment in wided-necked aneuryms while some thromboembolic complications were reported due to its incomplete stent apposition (ISA). We report our experiences on the novel Enterprise2 (EP-VRD2) stent in vivo in the treatment of intracranial and cranial cervical junction aneurysms.

Methods: Twenty-five consecutive patients with intracranial or cranial cervical junction aneurysms were treated with EP-VRD2 stents retrospectively collected in our institution. We use the ‘jailing' technique in all cases and deployed the stent by using pushing over the outer curve technique. The 3- or 6-monthS follow-up was done regularly by DSA.

Results: Twenty-five EP-VRD2 stents were implanted to treat 21 aneurysms at the siphon segment of internal carotid artery (ICA), one at the petrous segment, two at the cervical segment, one at the verteral artery with five accompanied with stenosis. Two patients had kinking during the procedure and were solved by microwire or microcatheter massaging. Four patients with a larger arc angle and a smaller radius of the parent vessel was detected ISA. No patient underwent the ischemic event after the operation. Twenty-three of 25 patients were evaluated after 3- or 6-months by DSA, 22 showed complete occlusion (RROC1), one slight re-stenosis in the follow-up within those five patients with stenosis. A length of 23 mm seemed associated with ISA (p < 0.01).

Conclusion: The EP-VRD2 performed well in our small patient series; however, ISA could still occur with a sharp angle of the parent vessel.

Initial Experience With the Next-Generation Resolute Onyx Zotarolimus-Eluting Stent in Symptomatic Intracranial Atherosclerotic Disease

Background and Purpose: Intracranial atherosclerotic disease (ICAD) is a common cause of stroke worldwide. Although there are different endovascular options for the treatment of symptomatic ICAD (sICAD), it is still controversial. Herein, we aim to study the safety and efficacy of a new generation of drug-eluting balloon-mounted stent (DES); Resolute (R) onyx DES in the treatment of sICAD.

Methods: A prospectively maintained neuroendovascular procedures database in a high-volume comprehensive stroke center was reviewed from October 2019 through January 2020. Patients were included if they had sICAD (≥70% stenosis), failed medical management, and underwent intracranial stenting with R-onyx DES. Technical success was defined as the ability to deploy the device at the desired location and achievement of <30% residual stenosis. The primary outcome was the occurrence of complications within 72 h of the procedure (strokes, ischemic or hemorrhagic; and mortality). Secondary outcomes included rates of symptomatic and angiographic recurrence within 6 months of the procedure.

Results: A total of 18 consecutive patients (mean age, 66.6 years; 44.4% were females and 94.4% were Hispanic) were eligible for the analysis. Indication for treatment was recurrent strokes in 13 and recurrent transient ischemic attack (TIA) in 5. A total of 22 symptomatic lesions with a mean baseline stenosis percent (84.9 ± 9.6) were treated using 23 R-onyx DES in 19 procedures. All procedures were done under general anesthesia with 100% technical success, and no reported periprocedural strokes or death. Among 13 patients who had clinical follow-up, 1 (7.7%) patient had TIA. There were no reported ischemic or hemorrhagic strokes. Angiographic follow-up for 9 (50%) patients showed no in-stent restenosis.

Conclusion: The use of R-onyx DES in the treatment of sICAD is safe with high technical success rates. Large prospective multicenter trials with long-term follow-up are warranted.

Incidence and Risk Factors of In-Stent Restenosis for Symptomatic Intracranial Atherosclerotic Stenosis: A Systematic Review and Meta-Analysis

BACKGROUND

In-stent restenosis affects long-term outcome in patients with intracranial atherosclerotic stenosis.

PURPOSE

The aim of this meta-analysis was to evaluate the incidence and risk factors of in-stent restenosis.

DATA SOURCES

All literature that reported in-stent restenosis was searched on PubMed, Ovid EMBASE and Ovid MEDLINE data bases.

STUDY SELECTION

Original articles about stents for symptomatic intracranial atherosclerotic stenosis were selected.

DATA ANALYSIS

Meta-analysis was conducted to derive the pooled in-stent restenosis using a random-effects model. Meta-regression was performed to explore the risk factors predisposing to in-stent restenosis.

DATA SYNTHESIS

In total, 51 studies with 5043 patients were included. The pooled incidence rate of in-stent restenosis was 14.8% (95% CI, 11.9%-17.9%). Among the lesions with in-stent restenosis, 28.8% of them led to (95% CI, 22.0%-36.0%) related neurologic symptoms. The series in the United States had a higher in-stent restenosis rate (27.0%; 95% CI, 20.6%-33.9%) compared with those from Asia (13.6%; 95% CI, 10.3%-17.2%) and other regions as a whole (7.6%; 95% CI, 1.1%-18.1%) (P < .01). Multiregression analysis revealed that younger patient age was related to high in-stent restenosis rates (P = .019), and vertebrobasilar junction location (P = .010) and low residual stenosis (P = .018) were 2 independent risk factors for symptomatic in-stent restenosis rate.

LIMITATIONS

The heterogeneity of most outcomes was high.

CONCLUSIONS

Our study showed promising results of in-stent restenosis for symptomatic atherosclerotic stenosis. Studies are needed to further expatiate on the mechanisms by which younger patient age, vertebrobasilar junction location, and low residual stenosis could increase in-stent restenosis and symptomatic in-stent restenosis, respectively.

Medium- and long-term effects of endovascular treatments for severely stenotic basilar arteries supported by multimodal imaging

BACKGROUND

To evaluate the medium-and long-term effect of intravascular interventional therapy for symptomatic severe basilar artery stenosis supported by multimodal imaging.

METHOD

After strict screening of 67 patients with symptomatic severe basilar artery stenosis (70-99%) with atherosclerotic stenosis, 67 patients with symptomatic recurrence after intensive drug treatment were treated with intravascular balloon dilatation and Enterprise stent implantation. Any stroke or death within 30 days after operation and any stroke and restenosis during medium-and long-term follow-up were recorded.

RESULTS

①The mean age of 67 patients (67lesions) was 57 ± 8 years old, and the technical success rate was 100%; ②Preoperative angiography showed that the collateral circulation was poor, and TICI was 1-2a while postoperative angiography showed that TICI was significantly improved to 2b-3; ③The average preoperative stenosis rate was 82 ± 9%, and the postoperative stenosis rate was reduced to 17 ± 10%; ④Before surgery, abnormal perfusion was found in the posterior circulation CTP; After the postoperative re-examination, the posterior circulation of CTP perfusion was significantly improved; ⑤Postoperative symptoms and neurological conditions improved significantly; ⑥Complications of perforating branch event occurred in 1 case after operation, and symptoms were relieved after more than 1 month of medication treatment, and mild neurological dysfunction remained. 1 case developed subacute thrombosis in the stent, which improved after active intra-arterial thrombolysis, and there was no residual neurological dysfunction; and 1 case of micro-guide wire being trapped by the distal vasospasm. ⑦67 patients were followed up by telephone, WeChat or imaging for 36-66 months.

CONCLUSIONS

In summary intravascular balloon dilation + Enterprise stent implantation is safe and effective for the treatment of symptomatic severe atherosclerotic stenosis of the basilar artery, with high technical success rate, low perioperative complications, and good mid-term and long-term effects.

Thirty-Day Outcomes of the Enterprise Stent in Treating Hypoperfusion of Symptomatic Intracranial Stenosis

OBJECTIVE

To evaluate the 30-day outcomes of using the Enterprise stent to treat patients with hypoperfusion of symptomatic severe intracranial stenosis.

METHODS

Patients with symptomatic severe intracranial stenosis (70%-99%) who underwent Enterprise stent intervention between August 2014 and November 2018 were retrospectively analyzed. The 30-day primary outcomes included the success rate of stenting and the incidence of complications, including ischemic stroke, cerebral hemorrhage, and death. The 30-day complication rates of patients with different lesion locations and classifications of Mori morphology were compared.

RESULTS

Sixty-eight patients were treated using 70 Enterprise stents. The success rate was 100%. The 30-day complication rate was 4.4%. The rates of ischemic stroke, cerebral hemorrhage, and death were 1.5%, 2.9%, and 0%, respectively. No significant difference was found in the 30-day complication rate between patients with different lesion locations and classifications of Mori morphology (P > 0.05).

CONCLUSION

Enterprise stents were relatively safe in treating patients with hypoperfusion of symptomatic severe intracranial stenosis.

Neuroform EZ Stenting for Symptomatic Intracranial Artery Stenosis: 30 Days Outcomes in a High-Volume Stroke Center

Objective: To test whether Neuroform EZ stent placement combined with the modified techniques in symptomatic severe intracranial stenosis (ICAS) would result in lower rates of peri-procedural complications of intracranial stenting. Methods: We retrospectively reviewed the clinical data from 71 consecutive patients who underwent Neuroform EZ stent placement combined with the modified techniques for symptomatic severe ICAS at our institute between January 2016 and October 2017. The primary outcomes were ipsi-lateral ischemic stroke, intra-cerebral hemorrhage, or death within 30 days after stenting. The secondary outcome was technical success. Results: The technical success rate was 100%. The mean pre and post-stent stenoses were 84.2% ± 9.1% (median 85%, IQR75% to 90%) and 16.9% ± 10.2 % (median 15%, IQR 10% to 25%). The frequency of ipsi-lateral stroke, intra-cerebral hemorrhage, or death within 30 days was 0%. Conclusions: The combined use of Neuroform EZ stent placement and the modified techniques for symptomatic severe ICAS is technically feasible and safe, with very low peri-procedural complications. Further studies are required to assess the long-term results of this approach.

Enterprise stent for symptomatic complex intracranial atherosclerotic stenosis: safety and efficiency

Purpose: To evaluate the safety and efficacy of Enterprise stent in the treatment of symptomatic complex intracranial atherosclerotic stenosis. Methods and materials: 20 complex cases among 53 patients with symptomatic ischemic stroke who were treated with balloon angioplasty and enterprise stents in Department of Neuro-interventional Radiology, The First Affiliated Hospital of Zhengzhou University from Jan. 2014 to Dec. 2017 were retrospectively enrolled in this study. Diagnostic criteria for complex intracranial atherosclerotic stenosis were as follows: 1) intracranial atherosclerotic stenosis was ≥70% confirmed by digital subtraction angiography (DSA) using the formulas described by the Warfarin Aspirin Symptomatic Intracranial Disease (WASID) method; 2) length of lesion was >10 mm. Basic characteristics of target lesions, technical success rate, perioperative safety, follow-up outcomes were investigated. Results: 20 patients were enrolled in this study, including 15 males and 5 females from 44 to 70 years old with an average age of 57.20 ± 9.25. 20 lesions were treated with 20 enterprise stents. The average preoperative and postoperative residual stenosis was reduced from (77.45 ± 8.44)% to (24.89 ± 16.61)%. The successful rate of operation was 100%. Among the perioperative complications, only 1 case (5%) experienced perforating branch event. The average clinical follow-up period was 13.15 ± 11.33 months (time range: 5-38). There were no ischemic events, no bleeding events and no various causes of death during the follow-up period. 8 lesions (40.0%) underwent DSA follow-up examinations and 12 lesions (60.0%) were checked by CT angiography during the follow-up period. 3 lesions (15.0%) developed ISR without any cerebral ischemia symptoms. Conclusion: This retrospective, single-center study suggests that enterprise stent is effective in the treatment of symptomatic complex intracranial atherosclerotic stenosis with less perioperative complications. Prospective, multicenter, randomized controlled trials are expected.

Medium-term results of undersized angioplasty and stenting for symptomatic high-grade intracranial atherosclerotic stenosis with Enterprise

PURPOSE

The aim of this retrospective study is to evaluate medium-term results of undersized balloon angioplasty and stenting for symptomatic high-grade (70-99%) stenosis of a major intracranial artery with Enterprise stent.

METHODS

This study included 68 consecutive symptomatic (recurrent transient ischemic attack (TIA) or ischemic stroke under dual antiplatelet treatment) patients with high-grade (70-99%) stenosis of a major intracranial artery who were endovascularly treated with undersized balloon angioplasty and Enterprise stent deployment between July 2012 and December 2017. Primary outcomes were any stroke or death within 30 days after procedure. Secondary outcomes were technical success rates, stroke and restenosis during the follow-up period.

RESULTS

A total of 68 lesions in 68 patients (mean age: 62 ± 7 years) were treated with a technical success rate of 99%. The degree of pre-procedural stenosis was 92 ± 6% and dropped to 12 ± 10% after stent deployment. No patient developed any stroke or death during the periprocedural period. Intracranial hemorrhage was observed in 1 (1.5%) patient. In 60 (88%) patients with available imaging follow-up in-stent restenosis was observed in 2 patients. Mean follow-up period was 22 ± 17 months (range 6-72) and none of the patients experienced recurrent TIA or stroke during the follow-up period.

CONCLUSION

In this retrospective single-center study undersized balloon angioplasty and deployment of a self-expandable stent with relatively low radial force was safe and effective for endovascular treatment of high-grade intracranial arterial stenosis with high technical success rate, low periprocedural complication rates and favorable medium-term follow-up results.

Endovascular Metal Devices for the Treatment of Cerebrovascular Diseases

Cerebrovascular disease involves various medical disorders that obstruct brain blood vessels or deteriorate cerebral circulation, resulting in ischemic or hemorrhagic stroke. Nowadays, platinum coils with or without biological modification have become routine embolization devices to reduce the risk of cerebral aneurysm bleeding. Additionally, many intracranial stents, flow diverters, and stent retrievers have been invented with uniquely designed structures. To accelerate the translation of these devices into clinical usage, an in-depth understanding of the mechanical and material performance of these metal-based devices is critical. However, considering the more distal location and tortuous anatomic characteristics of cerebral arteries, present devices still risk failing to arrive at target lesions. Consequently, more flexible endovascular devices and novel designs are under urgent demand to overcome the deficiencies of existing devices. Herein, the pros and cons of the current structural designs are discussed when these devices are applied to the treatment of diseases ranging broadly from hemorrhages to ischemic strokes, in order to encourage further development of such kind of devices and investigation of their use in the clinic. Moreover, novel biodegradable materials and drug elution techniques, and the design, safety, and efficacy of personalized devices for further clinical applications in cerebral vasculature are discussed.

Percutaneous Transluminal Angioplasty with Stent Placement versus Best Medical Therapy Alone in Symptomatic Intracranial Arterial Stenosis: A Best Evidence Review

Intracranial arterial stenosis (ICAS) is a common cause of stroke, and the risk of ischemic stroke from a stenotic intracranial artery remains high despite best medical therapy (BMT). As a result, clinicians have increasingly turned to percutaneous transluminal angioplasty and stenting (PTAS) over the last decade as an alternative therapy in high-risk patients with symptomatic ICAS. In this review, we will critically analyze multiple clinical trials to assess the safety and efficacy of PTAS with BMT versus BMT alone. The Stenting and Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis (SAMMPRIS) trial reported a higher rate of stroke or death within 30 days in the PTAS plus BMT group (14.7%) than the BMT only group (5.8%, p = 0.002). The rate of any stroke during the follow-up period (mean = 32 months) was higher in the PTAS plus BMT group (22.3%) than the BMT only group (14.1%, p = 0.03). The Vitesse Intracranial Stent Study for Ischemic Stroke Therapy (VISSIT) trial reported a higher rate of stroke or death within 30 days in the PTAS plus BMT cohort (24.1%) than the BMT only cohort (9.4%, p = 0.05). There was also a higher rate of hard transient ischemic attack (TIA) or stroke within one year in the PTAS plus BMT group (36.2%) than the BMT only group (15.1%, p = 0.02). The Vertebral Artery Ischaemia Stenting (VIST) trial reported the rate of any stroke during the follow-up period to be two events in 50 person-years in the PTAS plus BMT cohort versus four events in 45 person-years in the BMT only cohort, with a calculated hazard ratio of 0.47 (p = 0.39). Vertebral Artery Stenting Trial (VAST) reported a higher incidence of stroke, MI, or vascular death in the PTAS with BMT cohort (22%) than the BMT only cohort (0%). Tang et al. reported no significant difference in the incidence of vascular events at one year and three years between the PTAS plus BMT and BMT only cohorts. However, the distribution of vascular events was more concentrated in the first postoperative week in the PTAS plus BMT cohort (75% of all vascular events) versus the BMT only cohort (17%). Feng et al. reported a lower periprocedural complication rate (9.1%) with the Enterprise stent in comparison to the Wingspan and balloon-expandable stents used in the SAMMPRIS and VISSIT trials. We conclude that PTAS should not be employed as first-line treatment in patients with symptomatic ICAS. However, PTAS should be considered in symptomatic ICAS patients that are hemodynamically unstable or have repeatedly failed BMT, especially at sites with lower rates of perioperative complications than those reported here.

Current Status and Future Perspective of Stenting for Symptomatic Intracranial Atherosclerotic Disease: A Meta-Analysis

The aim of this study was to evaluate the safety and effectiveness of percutaneous transluminal angioplasty and stenting (PTAS) for intracranial atherosclerotic disease (ICAD) by conducting a meta-analysis. Two independent observers searched PubMed, EMBASE, and Cochrane Library for relevant studies up to 31 December 2016. A meta-analysis was conducted using Review Manager 5.3. Three studies involving 581 cases were included. The meta-analysis indicated that any stroke (RR = 3.13; 95% CI: 1.80-5.42), ischemic stroke (RR = 2.15; 95% CI: 1.19-3.89), and intracranial hemorrhage (RR = 14.71; 95% CI: 1.96-110.48) within 30 days in medical therapy alone were lower compared with PTAS plus medical therapy, but there were no significant differences in any stroke and ischemic stroke beyond 30 days between the two groups. There were also no significant differences in any death and myocardial infarction between the two groups. This meta-analysis demonstrated that, compared with medical therapy alone, PTAS for ICAD had a high risk of complication, but most complications in PTAS group occurred within 30 days after the operation, and beyond 30 days the PTAS was not inferior compared with medical therapy alone. Further studies are needed to reduce the periprocedural complications and reappraise the PTAS.

Spanning from the West to East: An Updated Review on Endovascular Treatment of Intracranial Atherosclerotic Disease

Ischemic stroke is a major cause of morbidity and mortality, incurring significant cost. Intracranial atherosclerotic disease (ICAD) accounts for 10-15% of ischemic stroke in Western societies, but is an underlying pathology in up to 54% of ischemic strokes in Asian populations. ICAD has largely been treated with medical management, although a few studies have examined outcomes following endovascular treatment. Our objective was to summarize the major trials that have been performed thus far in regard to the endovascular treatment of ICAD and to provide direction for future management of this disease process. Systematic review of the literature from 1966 to 2015, was conducted in regard to intracranial angioplasty and stenting. Studies were analyzed from PubMed, American Heart Association and Society of Neurointerventional Surgery databases. SAMMPRIS and VISSIT are the only randomized controlled trials from which Western guidelines of intracranial stenting have been derived, which have displayed the superiority of medical management. However, pooled reviews of smaller studies and other nonrandomized trials have shown better outcomes with endovascular therapy in select patient subsets, such as intracranial vertebrobasilar stenosis or in the presence of robust collaterals. Suboptimal cases, including longer lesions, bifurcations and significant tortuosity tend to fair better with medical management. Medical management has been shown to be more efficacious with less adverse outcomes than endovascular therapy. However, the majority of studies on endovascular management included a diverse patient population without ideal selection criteria, resulting in higher adverse outcomes. Population analyses and selective utilization of endovascular therapy have shown that the treatment may be superior to other management in select patients.

In vitro comparison of intracranial stent visibility using various concentrations of gadolinium contrast agent under 1.5 T and 3 T MR angiography

Background and purpose

MR angiography (MRA) is an increasingly used evaluation method following intracranial stenting. However, the various artifacts created by the stent limit this technique. The purpose of this study was to investigate the effects of various concentrations of gadolinium contrast agent on the visibility and signal characteristics of two stents using the a contrast enhanced MRA technique.

Material and method

Two intracranial stents (Enterprise and Helistent) were placed in polyvinyl chloride tubes as vascular phantoms. They were filled with six different doses of gadolinium contrast agent (1.0, 2.0, 4.0, 6.0, 8.0, and 10.0 mmol/L dimeglumine gadopentetate, respectively) and imaged using 3 T and 1.5 T MR systems. Relative in-stent signal (RIS) was calculated and artificial luminal narrowing (ALN) was obtained using pixel by pixel analysis.

Result

The Enterprise stent, performed in both 1.5 T and 3 T MR systems, showed mean RIS values much less than those for the Helistent for all different doses of gadolinium solution. Increased gadolinium concentration resulted in a gradual reduction in RIS values in the Enterprise group. Also, ALN in the Enterprise group showed no or little change with various gadolinium doses.

Conclusions

The Enterprise stent demonstrated good luminal visibility regardless of gadolinium concentration. The relative in-stent signals were more predictable in the Enterprise stent with various doses of gadolinium. Therefore, the Enterprise stent has been shown to provide better in-stent visibility compared with the Helistent using various gadolinium doses.