Usefulness of Self-Expandable Stent for Recanalization of Intracranial Atherosclerotic Disease: Preliminary Experience with Enterprise Stent

Purpose

The purpose of this preliminary study is to evaluate the efficacy and safety of the Enterprise stent for intracranial atherosclerotic disease (ICAD) in patients who presented with acute stroke due to vessel steno-occlusion and in patients with symptomatic disease despite optimum medical management.

Materials and Methods

A retrospective data analysis was performed on 15 consecutive patients who were treated with Enterprise stenting for recanalization of symptomatic intracranial steno-occlusive arteries due to underlying ICAD. Their clinical and radiological data were reviewed to evaluate procedural results, periprocedural and postprocedural complications, and clinical outcome.

Results

Enterprise stents were deployed as a rescue method in 15 patients for recanalization of steno-occlusion. All patients achieved final modified thrombolysis in cerebral infarction (mTICI) score improvement (53.3% with a mTICI score from 0 to 2b or 3, 46.7% with a mTICI score from 1 to 3). Two postprocedural complications (1 symptomatic intracranial hemorrhage and 1 severe brain edema, 13.3%) occurred among 15 patients. Among 12 patients with acute ischemic stroke (AIS), 6 patients (50%) had improvement in their National Institute of Health Stroke Scale of more than 4 at discharge. Seven patients (58.3%) had a good functional outcome with 3-month modified Rankin Score (mRS)≤2, and mortality occurred (mRS=6) in 2 patients (16.7%). None of the 10 AIS and 3 transient ischemic attack patients experienced further ischemic events attributable to the treated steno-occlusion during the follow-up period (ranged from 4 to 36 months, median 12 months).

Conclusion

This retrospective study suggests that Enterprise stenting can effectively and safely achieve recanalization in symptomatic steno-occlusive intracranial arteries.

Outcome of Wingspan Stent Using Aggressive Post-stent Balloon Dilation for Intracranial Atherosclerosis Stenosis

Background: Wingspan stent has gained interest for better long-term outcomes for intracranial atherosclerosis disease (ICAD). However, in-stent restenosis still presents as a problem and may cause postoperative neurological events. We aimed to find a way to prevent in-stent restenosis.

Method: Patients with stenosis >70% ICAD were treated with wingspan stent and were retrospectively reviewed. The patients were separated into two groups: one with post-dilation and the other without post-dilation. The outcomes of wingspan stenting were compared immediately after the surgery and at a 1-year follow-up.

Results: Overall, 28 patients were included for analysis, with 15 patients undergoing post-dilation and 13 patients not undergoing the procedure. The extent of stenosis was significantly lower in the post-dilation group than in the no post-dilation group, both immediately after the surgery (14.8 ± 10.2 vs. 28.5 ± 14.5%, p < 0.01) and at 1-year follow-up (25.8 ± 18.0 vs. 50.1 ± 23.2%, p < 0.01). The post-dilation method immediately expanded the stent diameter (2.89 ± 0.48 vs. 3.05 ± 0.44 mm, p < 0.001), and the diameter still increased at 1-year follow-up (3.05 ± 0.44 vs. 3.12 ± 0.43 mm, p < 0.01) due to the self-expandable property of the wingspan. Similarly, in the no post-dilation group, the stent size was also increased (2.70 ± 0.67 vs. 2.80 ± 0.64 mm, p < 0.01). However, at 1-year follow up, the luminal diameter was stationary in the post-dilation group (2.36 ± 0.73 vs. 2.46 ± 0.82 mm, p = 0.88) and decreased in the no post-dilation group (2.24 ± 0.56 vs. 1.60 ± 0.79 mm, p < 0.01). The periprocedural complication rate was similar between the groups.

Conclusion: The post-dilation method can be feasibly performed and can offer better stent expansion and apposition in the wingspan system. By applying this technique, we might prevent in-stent restenosis and improve neurological outcomes.

Recurrent in-stent thrombosis following V4 segment of vertebral artery stenting: A case report

INTRODUCTION AND IMPORTANCE

We report a rare case of subacute recurrent in-stent thrombosis after vertebral artery stenting of the left intracranial segment.

CASE PRESENTATION

A 56-year-old man presented with V4 segment severe stenosis of the left vertebral artery. Stent (Apollo, 2.5 mm × 8 mm) implantation was performed for severe stenosis of the left vertebral artery. Approximately 48 h after operation, the patient developed dizziness and drowsiness. DSA showed stent thrombosis, which was treated by PTAS (Apollo, 2.5 mm × 13 mm), and the preoperative symptoms resolved. Two days later, symptoms of posterior circulation ischemia reappeared, DSA showed recurrence of stent thrombosis and CYP2C19 genotypic analysis showed intermediate metabolizers. Revision PTAS (Enterprise, 4.5 mm × 28 mm) was performed followed by administration of Ticagrelor instead of tirofiban. The patient showed good neurological outcomes. CTA performed both one week and four months after the operation showed that the blood flow of the left vertebral artery was unobstructed.

CLINICAL DISCUSSION

Endovascular therapy is an alternative treatment for severe intracranial vascular stenosis, and reocclusion is one of the serious complications.

CONCLUSION

our case report highlights that recurrent in-stent thrombosis maybe be caused by inadequate preoperative assessment and unsuitable therapeutic drug selection for the stents.

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.

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.

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.

Bench-Top Comparison of Three Different Types of Stents Used for Treatment of Intracranial Atherosclerotic Stenosis

Purpose

Four key bench-top tests, including trackability, conformability, wall-apposition, and bending stiffness, were performed to understand the mechanical characteristics in 3 different types of stents applicable for treatment of intracranial atherosclerotic stenosis: Balloon-expandable D⁺Storm, Pro-Kinetic Energy, and self-expandable Wingspan stents.

Materials and Methods

Trackability was assessed by measuring the tracking forces of each stent with its delivery systems. Conformability and wall apposition were quantified and analyzed using curved vessel models. A 3-point bending test was employed to evaluate bending stiffness.

Results

D⁺Storm showed the lowest tracking forces while the conformability of the Wingspan stent was superior to that of the tested stents. Pro-Kinetic Energy and D⁺Storm had better wall apposition in curved vessels than the Wingspan stent. Bending stiffness of the Wingspan stent was notably lower, whereas no significant differences were found between D⁺Storm and Energy. Pro-Kinetic Energy and D⁺Storm not only indicated lower gap ratios between the struts and the vessel wall but also maintained good wall apposition even in the curved model.

Conclusion

These bench-top measurements may provide clinicians with useful information in regard to selecting suitable stents for treatment of intracranial atherosclerotic stenosis.

Tandem Short-length Multi-stent Construct for Emergent Revascularization of Occlusive Long-segment Left Middle Cerebral Artery In-stent Stenosis

Endovascular stenting and balloon angioplasty is a feasible although controversial option for intracranial atherosclerotic stenosis refractory to maximize medical management. High rates of symptomatic in-stent restenosis (ISR) have been identified with Wingspan stent (Stryker, Fremont, CA, USA) placement. Revascularization of ISR by way of re-stenting is often attempted, albeit with high risk and low durability. In lesions with long-segment non-focal critical or emergent occluded stenosis, re-stenting with a single balloon mounted stent is not possible due to deliverability of a lengthy device through a tortuous carotid siphon. Tandem drug-eluting stent placement within the middle cerebral artery to address acute, occlusive ISR using a Wingspan stent, with additional stent reconstruction, has not been previously described.

Long-term Outcome of Angioplasty Using a Wingspan Stent, Post-Stent Balloon Dilation and Aggressive Restenosis Management for Intracranial Arterial Stenosis

PURPOSE

To investigate the long-term outcome of stent angioplasty for symptomatic severe intracranial artery stenosis.

METHOD

In this study 95 consecutive patients with intracranial atherosclerotic stenosis (>70%) underwent stent angioplasty using Wingspan stents. The primary endpoints were stroke or death within 30 days of the procedure and subsequent stroke attributed to the stented vessel. Disabling stroke was defined as stroke with a modified Rankin scale > 3. Secondary endpoints included transient ischemic attacks, contralateral stroke, nonstroke death, and other events. Patients underwent prestent balloon dilation with or without poststent balloon dilation, close restenosis follow-up, and selective retreatment, as required.

RESULT

The mean follow-up duration was 34.9 ± 23.3 months. Primary endpoint events occurred in 23% of the patients. The median infarction volume was 2.6 ml, and 11 (68%) of 16 infarctions were <5 ml in volume. Disabling stroke occurred in 3% of patients. The primary endpoint rates were 17.9% within 30 days and 2.1% from 30 days to 1 year. Secondary endpoint events occurred in 27.3% of the patients. Mean stenosis was reduced from 76.8 ± 6.1% to 7.5 ± 13.4%. Of 80 patients who underwent angiographic follow-up, 11 (14%) experienced restenosis (≥50%) and 7 (9%) exhibited restenosis-related symptoms of transient ischemic attack. The rate of symptomatic restenosis was significantly higher in patients who underwent prestent balloon dilation alone than in patients who underwent prestent and poststent balloon dilation (p = 0.016).

CONCLUSION

The postprocedural stroke rate was similar to that observed in the SAMMPRIS study. Symptomatic restenosis may be reduced by poststent dilation, close angiographic follow-up, and retreatment.

Weighing in on the Off-Label Use: Initial Experience of Neuroform EZ Stenting for Intracranial Arterial Stenosis in 45 Patients

Background: The role of stenting for intracranial arterial stenosis (ICAS) has been increasingly debated due to negative results of randomized trials. Thus, exploration of more appropriate devices may hopefully shed light on the endovascular approach, especially for patients with recalcitrant ICAS related to a high risk of stroke. We sought to present and analyze the data of Neuroform EZ stenting for medically refractory ICAS in a single-center series.

Materials and methods: Between November 2016 and January 2018, 45 consecutive patients treated with the Neuroform EZ stent were included in our retrospective study. Outcomes evaluation included successful procedure rate, vascular event within 30 days and recurrent stenosis for at least 6 months after the procedure.

Results: The technical success rate was 100% for all 46 stenotic lesions. Mean pre-stent stenosis was 86.5 ± 8.7%, improving to 23.7 ± 18.1% after stenting. Combined procedure related vascular event rate was 2.2% (n = 1) within 30 days after the procedure. No in-stent restenosis was observed during an average follow-up period of 7.3 months.

Conclusion: The Neuroform EZ stent system could serve as an off-label but promising optional device for ICAS stenting in a carefully selected subgroup of patients. Further longer-term clinical follow-up is mandatory to validate our initial results.

Intracranial Stenting after Failure of Thrombectomy with the emboTrap® Device

BACKGROUND

Approved alternatives in the guidelines for acute ischemic stroke patients who have failed intracranial thrombectomy are lacking. Primary permanent intracranial stenting was initially used in the era before thrombectomy and might still be a useful rescue treatment in acute stroke patients suffering from ongoing large vessel occlusion refractory to thrombectomy.

METHODS

The prospectively collected registry of patients with acute stroke caused by large vessel occlusions and treated with the emboTrap® device in Karolinska Hospital from October 2013 through March 2017 were retrospectively reviewed. Clinical outcome of non-recanalized patients with a thrombolysis in cerebral infarction (TICI) score of 0-1 after failed thrombectomy were compared with those who were treated with permanent intracranial stenting as rescue therapy. Favorable outcome was defined as modified Rankin scale 0-2.

RESULTS

The emboTrap® device was used in 201 patients. Persistent re-occlusions on withdrawal of the thrombectomy device were seen in 26 patients (13%) and of those, 12 individuals (46%) were treated with intracranial stenting. Baseline National Institutes of Health stroke scale (NIHSS), occlusion site, and onset-to-puncture time did not differ between the stenting group and the non-recanalized group. During the procedure half dose (5/12 patients) or full dose abciximab (6/12 patients), or aspirin (1/12 patient) was given intravenously immediately after stent placement. In 2 patients (17%) multiple stents were implanted. The stenting group had better functional outcomes at 3 months compared to the non-stenting group with 8/12 (66%) vs. 3/14 (21.4%, p < 0.05). Of the patients 5 (36%) in the non-stented group had died at 3 months follow-up, whereas mortality in the stenting cohort was 0% (p < 0.05) and no symptomatic intracranial hemorrhage (ICH) occurred in either group.

CONCLUSION

Intracranial stenting after failure of recanalization with thrombectomy led to a better rate of clinical outcome than leaving the patient non-recanalized. The required antiplatelet therapy, predominantly abciximab, did not lead to additional ICH.

Nonprocedural Symptomatic Infarction and In-Stent Restenosis After Intracranial Angioplasty and Stenting in the SAMMPRIS Trial (Stenting and Aggressive Medical Management for the Prevention of Recurrent Stroke in Intracranial Stenosis)

BACKGROUND AND PURPOSE

The purpose of this study was to investigate the frequency of symptomatic in-stent restenosis (ISR) and its contribution to nonprocedural symptomatic infarction in the SAMMPRIS trial (Stenting and Aggressive Medical Management for the Prevention of Recurrent Stroke in Intracranial Stenosis).

METHODS

Patients without a periprocedural primary end point were followed up to determine the occurrence of any of the following events: ischemic stroke, cerebral infarct with temporary signs, or transient ischemic attack in the territory of the stented artery. Vascular imaging performed after these events was reviewed for ISR. Annual rates for symptomatic ISR were calculated using Kaplan-Meier estimates.

RESULTS

Of 183 patients in the stenting group without a periprocedural primary end point, 27 (14.8%) had a symptomatic infarction (stroke or cerebral infarct with temporary signs) and 16 (8.7%) had transient ischemic attack alone in the territory during a median follow-up of 35.0 months. Of the 27 patients with infarctions, 17 (9.3%) had an ischemic stroke and 10 (5.5%) had a cerebral infarct with temporary signs alone. Adequate vascular imaging to evaluate ISR was available in 24 patients with infarctions (showing ISR in 16 [66.7%]) and in 10 patients with transient ischemic attack alone (showing ISR in 8 [80%]). The 1-, 2-, and 3-year rates (with 95% confidence limits) for symptomatic ISR in the SAMMPRIS stent cohort were 9.6% (6.1%-14.9%), 11.3% (7.5%-17.0%), and 14.0% (9.6%-20.2%), respectively.

CONCLUSIONS

Symptomatic ISR occurred in at least 1 of 7 patients in SAMMPRIS by 3 years of follow-up and was likely responsible for the majority of nonprocedural cerebral infarctions.

CLINICAL TRIAL REGISTRATION

URL: https://clinicaltrials.gov. Unique identifier: NCT00576693.

Severe symptomatic intracranial internal carotid artery stenosis treated with intracranial stenting: a single center study with 58 patients

PURPOSE

We aimed to investigate the safety and effectiveness of intracranial stenting in a population with severe (≥ 70%) symptomatic intracranial internal carotid artery (ICA) atherosclerotic stenosis.

METHODS

Fifty-eight patients with severe intracranial ICA atherosclerotic stenosis were prospectively enrolled. The baseline data, cerebral angiography, success rate, perioperative complications, clinical and imaging follow-up were prospectively analyzed.

RESULTS

All patients had successful intracranial stenting (100%), and the mean degree of stenosis was improved from 84.3% ± 7.5% to 23.5% ± 5.1% after the stent procedure. During the 30-day perioperative period, only one patient (1.7%) had ischemic stroke. Seven patients (12.1%) had headache and dysphoria. Thirty-six patients (62.1%) had clinical follow-up for 6-68 months after stenting. Five female patients (13.9%) had ipsilateral stroke including one death, but no disabling stroke, while three other patients (8.3%) had ipsilateral temporary ischemic attack (TIA). The recurrent stroke rate was higher in patients presenting with stroke (4/17, 23.5%) than in patients presenting with TIA (1/19, 5.3%), with no statistical significance (P = 0.33). Thirteen patients (22.4%) had imaging follow-up of 5-12 months following stenting, five of whom (38.5%) had in-stent restenosis.

CONCLUSION

Intracranial stenting for patients with intracranial ICA atherosclerotic stenosis has a low perioperative stroke rate and decent outcome on long-term follow-up, despite a relatively high in-stent restenosis rate.

Undersized angioplasty and stenting of symptomatic intracranial tight stenosis with Enterprise: Evaluation of clinical and vascular outcome

BACKGROUND

Severe intracranial arterial stenosis results in more than 10% incidence of stroke and transient ischemic attack. Using undersized angioplasty with off-label closed-cell Enterprise stent may be a feasible alternative option for treating patients with intracranial atherosclerotic disease who fail dual-antiplatelet medical therapy. The results of the authors' study are presented in this paper.

MATERIALS AND METHODS

Between January 2013 and July 2014, 24 symptomatic patients with a total of 30 intracranial arterial stenotic lesions refractory to medical therapy, who underwent undersized angioplasty and Enterprise stenting, were retrospectively reviewed in the authors' institution. The results evaluated include technical success rate, clinical outcome measured as modified Rankin Scale at presentation and follow-up, peri-procedural morbidity within 30 days and 1 year, and follow-up vessel patency.

RESULTS

Stent deployment was successfully achieved in all stenotic lesions (30/30). Mean pre-stent and post-stent diameter residual stenosis was 81% and 18%, respectively. The peri-procedural complication rate during 30 days after stenting was 10% per lesion (3/30), including intracranial hemorrhage, in-stent thrombosis and ischemic stroke. No further thromboembolic event or complication occurred in any patient more than 30 days after stenting. Modified Rankin scale ≤ 2 was observed in 64% and 83% of patients at initial presentation and follow-up (mean 15.8 months), respectively. Imaging follow-up was available in 17 of 24 patients (70.8%) and 20 of 30 treated lesions (66.6%) with a mean follow-up period of 15.4 months. Only one asymptomatic in-stent restenosis occurred in 20 available lesions (5.0%).

CONCLUSION

This preliminary study suggests that using undersized angioplasty and Enterprise stenting may effectively treat high-degree symptomatic intracranial arterial stenosis with favorable clinical and angiographic outcome.

Delayed Stenosis in the Intracranial Vessels following Endovascular Treatment for Acute Stroke

PURPOSE

To evaluate delayed stenosis of the vessels after endovascular thrombectomy using magnetic resonance (MR) angiography.

MATERIALS AND METHODS

Of 82 consecutive patients who underwent successful endovascular treatment for acute intracranial large vessel occlusion between October 2010 and October 2014 at a single institution, 57 patients for whom 3-month radiologic follow-up examinations using MR angiography were available were included in the analysis. MR angiography images were assessed to detect delayed stenosis, which was defined as a decrease in the diameter of treated vessels > 50% compared with MR angiography images obtained 24 hours after endovascular treatment.

RESULTS

MR angiography images obtained 3 months after endovascular treatment revealed delayed stenosis of treated vessels in five (8.8%) of 57 patients. All cases of delayed stenosis were asymptomatic and occurred in the middle cerebral artery (MCA). Further serial radiologic follow-up showed gradual improvement of all delayed stenosis over 12 months.

CONCLUSIONS

Endovascular treatment poses a risk of delayed stenosis of treated vessels, especially in the MCA. MR angiography is a useful modality in long-term follow-up to evaluate delayed stenosis after endovascular treatment.

Wingspan Stenting for Severe Symptomatic Intracranial Atherosclerotic Stenosis in 433 Patients Treated at a Single Medical Center

Purpose

To investigate the safety and outcome of intracranial stenting for intracranial atherosclerotic stenosis (IAS).

Materials and Methods

Between July 2007 and April 2013, 433 consecutive patients with IAS >70% underwent intracranial Wingspan stenting, and the data were prospectively analyzed.

Results

Intracranial stenting was successful in 429 patients (99.1%), and the mean stenosis rate was improved from prestenting (82.3± 7.6)% to poststenting (16.6 ± 6.6)%. During the 30-day perioperative period, 29 patients (6.7%) developed stroke. The total perioperative stroke rate was significantly (P <0.01) higher in the basilar artery area than in others, whereas the hemorrhagic stroke rate was significantly (P <0.05) greater in the middle cerebral artery area than in others. The experience accumulation stage (13%) had a significantly (P <0.05) higher stroke rate than the technical maturation stage (4.8%). Clinical follow-up 6–69 months poststenting revealed ipsilateral stroke in 20 patients (5.5%). The one- and two-year cumulative stroke rates were 9.5% and 11.5%, respectively; the two-year cumulative stroke rate was significantly (P <0.05) greater in the experience accumulation stage (18.8%) than in the technical maturation stage (9.1%).

Conclusion

Wingspan stenting for intracranial atherosclerotic stenosis is safe and the long-term stroke rate after stenting is low in a Chinese subpopulation.

In-Pipeline Stenosis

BACKGROUND:

The Pipeline Embolization Device is a widely utilized flow diverter in the treatment of intracranial aneurysms.

OBJECTIVE:

To assess the incidence, clinical significance, predictors, and outcomes of in-Pipeline stenosis (IPS).

METHODS:

Angiographic studies in 139 patients treated between 2011 and 2013 were independently reviewed by 2 authors for the presence of IPS. Multivariable logistic regression analysis was conducted to determine predictors of IPS.

RESULTS:

A total of 21 (15.8%) patients demonstrated some degree of IPS during the follow-up period at a mean time point of 6.7 months (range, 3–24 months). The stenosis was mild (&lt;50%) in 11 patients, moderate (50%-75%) in 5, and severe (&gt;75%) in 6. None were symptomatic or required further intervention. Sixteen of these 22 patients (73%) had IPS detected within 6 months. IPS was noted in 7.6% (1/13) of patients with posterior circulation aneurysms vs 16.7% (21/126) of those with anterior circulation aneurysms (P = .03). The rate of IPS was 60% (3/5) in patients who did not receive aspirin vs only 14.2% (19/134) in those who received aspirin (P = .02). In multivariable analysis, no aspirin therapy (odds ratio, 10.0; 95% confidence interval, 1.4–67.7; P = .02) and internal carotid artery aneurysm location (odds ratio, 3.1; 95% confidence interval, 1.1–8.8; P = .03) were strong independent predictors of IPS.

CONCLUSION:

IPS is a common, early, and mostly benign complication. Patients with internal carotid artery aneurysms are more likely to develop IPS. Aspirin plays a key role in preventing IPS. The results of this study further support the safety of flow diverters.

Symptomatic intracranial vertebral artery atherosclerotic stenosis (≥70%) with concurrent contralateral vertebral atherosclerotic diseases in 88 patients treated with the intracranial stenting

PURPOSE

To investigate the safety, effect and instent restenosis rate of Wingspan stenting in treating patients with intracranial vertebral artery atherosclerotic stenosis (70-99%) concurrent with contralateral vertebral artery atherosclerotic diseases.

MATERIALS AND METHODS

Eighty-eight patients with severe symptomatic intracranial vertebral artery atherosclerotic stenosis (≥70%) combined with contralateral vertebral artery atherosclerotic diseases were treated with the Wingpsan stent. All the baseline, cerebral angiography, success rate, perioperative complications, clinical and imaging follow-up data were prospectively analyzed.

RESULTS

The success rate of stenting was 100%, and the mean stenotic rate was reduced from prestenting (84.9±6.8)% to poststenting (17.2±5.9)%. The perioperative stroke rate was 1.1%. Among eighty patients (90.9%) with clinical follow-up 8-62 months (mean 29.3±17.2) poststenting, five (6.3%) had posterior circulation TIA only, three (3.8%) had mild stroke in the posterior circulation but recovered completely, and another five patients greater than 70 years old died of non-ischemic stroke. Imaging follow-up in 46 patients (52.3%) 5-54 months (mean 9.9±9.9) following stenting revealed instent restenosis in 12 patients (26.1%) including 7 (58.3%) symptomatic restenosis. Age and residual stenosis were the two factors to significantly (P<0.05) affect instent restenosis.

CONCLUSION

Wingspan stenting in the intracranial vertebral artery atherosclerotic stenosis combined with contralateral vertebral artery atherosclerotic diseases has a low perioperative stroke rate and a good preventive effect on long-term ischemic stroke, but the instent restenosis rate is a little high.

Stenting in Intracranial Stenosis: Current Controversies and Future Directions

Angioplasty and stenting for intracranial atherosclerotic stenosis (ICAS) are a last resort for patients with high-grade intracranial stenosis with multiple ischemic events unresponsive to medical therapy. Medical management, consisting of aggressive risk factor control and dual antiplatelet therapy, is superior to angioplasty and stenting for the prevention of future stroke. Future studies of angioplasty and stenting in this population are important, as the stroke risk on medical therapy is 12 % at 1 year and post-procedure stroke rates are similar to rates with medical treatment. There are many issues that will need to be resolved for stenting to offer any benefit, however. Procedural risks of hemorrhagic and ischemic stroke are unacceptably high. High-risk subgroups, potentially based on hemodynamic factors, will need to be identified for future interventional trials. Nevertheless, it is still reasonable to consider angioplasty and stenting for selected patients with multiple recurrent events despite aggressive medical management, but benefits are unclear at this time.

Solitaire stents for the treatment of complex symptomatic intracranial stenosis after antithrombotic failure: safety and efficacy evaluation

OBJECTIVES

To evaluate the feasibility, safety, and efficacy of Solitaire stent placement after balloon angioplasty for the treatment of complex symptomatic intracranial atherosclerotic stenosis (ICAS).

METHODS

We retrospectively reviewed the clinical data from 44 patients who underwent Solitaire stent placement for complex symptomatic ICAS at our department between November 2010 and March 2014, with focus on the clinical factors, lesion characteristics, treatment results, and periprocedural complications. We also summarized the early outcomes and imaging findings during the follow-up period.

RESULTS

Overall, the technical success rate was 100% (44/44). Post-stenting residual stenosis ranged from 0% to 40% (mean 15.00±12.94%). The overall 30-day rate of procedure-related complications was 9.09% (4/44). The incidence of recurrent ischemic events related to the territory artery was 4.55% during a mean clinical follow-up period of 25.5 months. Five patients (11.36%) developed in-stent restenosis during a mean angiographic follow-up period of 9.3 months.

CONCLUSIONS

This is the first case series study of ICAS treated by Solitaire stent placement. Deployment of a Solitaire stent with balloon angioplasty in the treatment of complex severe intracranial stenosis appears safe and effective, with a high technical success rate, relatively low periprocedural complication rate, and favorable outcome during follow-up.

Reappraisal of primary balloon angioplasty without stenting for patients with symptomatic middle cerebral artery stenosis

There is a controversy regarding the safety and efficacy of intracranial stenting. We describe our experience with primary balloon angioplasty without stenting for symptomatic middle cerebral artery (MCA) stenosis. All patients who underwent balloon angioplasty without stenting for MCA stenosis between 1996 and 2010 were retrospectively reviewed. We evaluated technical success rates, degrees of stenosis, and stroke or death within 30 days. Among patients who were followed-up for > 1 year we evaluated latest functional outcomes, stroke recurrence at 1 year, and restenosis. In total 45/47 patients (95.7%) were successfully treated. Average pre- and postprocedure stenosis rates were 79.9% and 39.5%, respectively. Three neurological complications occurred within 30 days: one thromboembolism during the procedure; one lacunar infarction; and one fatal intraparenchymal hemorrhage after the procedure. Stroke or death rate within 30 days was 6.4%. Thirty-three patients were available for follow-up analysis with a mean period of 51.5 months. The combined rate of stroke or death within 30 days and ipsilateral ischemic stroke of the followed-up patients within 1 year beyond 30 days was 9.4%. Restenosis was observed in 26.9% of patients and all remained asymptomatic. In our retrospective series, balloon angioplasty without stenting was a safe, effective modality for symptomatic MCA stenosis. For patients refractory to medical therapy, primary balloon angioplasty may offer a better supplemental treatment option.

Balloons in endovascular neurosurgery: history and current applications

The use of balloons in the field of neurosurgery is currently an essential part of our clinical practice. The field has evolved over the last 40 years since Serbinenko used balloons to test the feasibility of occluding cervical vessels for intracranial pathologies. Since that time, indications have expanded to include sacrificing cervical and intracranial vessels with detachable balloons, supporting the coil mass in wide-necked aneurysms (balloon remodeling technique), and performing intracranial and cervical angioplasty for atherosclerotic disease, as well as an adjunct to treat arteriovenous malformations. With the rapid expansion of endovascular technologies, it appears that the indications and uses for balloons will continue to expand. In this article, we review the history of balloons, the initial applications, the types of balloons available, and the current applications available for endovascular neurosurgeons.

Temporal correlation between wall shear stress and in-stent stenosis after Wingspan stent in swine model

BACKGROUND AND PURPOSE

A recent randomized clinical trial on intracranial atherosclerosis was discontinued because of the higher frequency of stroke and death in the angioplasty and stent placement group than in the medical treatment group. An in-depth understanding of the relationship between biologic responses and flow dynamics is still required to identify the current limitations of intracranial stent placement.

MATERIALS AND METHODS

Five Wingspan stents were deployed in tapered swine ascending pharyngeal arteries. Temporal wall shear stress distributions and in-stent stenosis were evaluated at days 0, 7, 14, and 28 after stent placement. The physiologic role of wall shear stress was analyzed regarding its correlation with in-stent stenosis.

RESULTS

In-stent stenosis reached a peak of nearly 40% at day 14 and decreased mainly at the distal stent segment until day 28. The wall shear stress demonstrated a characteristic pattern with time on the basis of the in-stent stenosis change. The wall shear stress gradient increased from the proximal to distal segment until day 14. At day 28, the trend was reversed dramatically, decreasing from the proximal to the distal segment. A significant correlation between the in-stent stenosis growth until day 14 and low wall shear stress values just after stent placement was detected. In-stent stenosis regression between days 14 and 28 was also associated with the high wall shear stress values at day 14.

CONCLUSIONS

These data suggest that the physiologic wall shear stress can control the biphasic in-stent stenosis change in tapered arteries.

Angioplasty and stenting of intracranial atherosclerosis with the Wingspan system: 1-year clinical and radiological outcome in a single Asian center

BACKGROUND

This study aimed to evaluate the 1-year clinical and angiographic outcome of angioplasty and stenting of intracranial atherosclerosis using Wingspan and Gateway system.

METHODS

In this prospective study, patients with symptomatic lesions were treated and followed clinically and angiographically by digital subtraction angiography (DSA) for 1 year. The two primary endpoints were recurrent ipsilateral ischemic stroke and in-stent restenosis (ISR) at 1 year. Secondary endpoints included periprocedural death or stroke and all strokes at 1 year. Potential factors correlated with ISR were studied using univariate and multivariate analysis.

RESULTS

Treatment was attempted in 65 patients and successfully completed in 61 (93.8%). Fifty-nine patients (44 men, 15 women) aged 62.86 ± 11.38 years with 66 stenoses (average degree of stenosis 71.78 ± 11.23%) underwent clinical and DSA follow-up at 1 year. There were 66 stenotic lesions. ISR occurred in 11 of the 66 lesions (16.7%). Luminal gain occurred in 32 of the lesions (48.5%), an unchanged lumen in 4 (6%) and luminal loss in 30 (45.4%). The periprocedural stroke or death rate was 6.1% (4/65), including three hemorrhagic and one ischemic stroke, all of which occurred at the corresponding site and resulted in death. There were no interval strokes between the periprocedural time and the 1-year follow-up. The occurrence of ISR was correlated with the degree of stenosis before treatment and was not correlated with patient age or sex, vessel diameter, location of stenosis or failure to control risk factors for atherosclerosis.

CONCLUSIONS

One-year clinical and angiographic outcomes of angioplasty and stenting are promising for symptomatic intracranial atherosclerosis.

Endovascular Advances for Intracranial Occlusive Disease

Stroke is the fourth leading cause of death in the United States. Intracranial atherosclerotic disease accounts for 8%-10% of ischemic stroke in the United States. So far, surgical bypass has not proved to be superior to medical therapy. As both medical and endovascular therapies for intracranial atherosclerosis evolve, so too do the guidelines for treatment. Initial reports on the results of stent placement for symptomatic high-grade intracranial atherosclerotic disease were encouraging; however, recent trials suggest that initial medical management may be preferable. Currently, intracranial angioplasty and stenting for symptomatic intracranial atherosclerosis is now more controversial. Further trials are necessary to help determine which patients are ideal for endovascular therapies.

Endovascular treatment of intracranial atherosclerotic disease

Stroke is the third leading cause of death in the United States. Intracranial atherosclerotic disease plays a role in cerebrovascular accidents, with well-characterized modifiable and nonmodifiable risk factors. Surgical bypass has so far not proved to be superior to medical therapy. Both medical and endovascular therapies for intracranial atherosclerosis have evolved since the initial off-label use of cardiac devices for its treatment. Initial reports on the results of stent placement for symptomatic high-grade intracranial atherosclerotic disease were initially encouraging. However, debate remains as to the optimal treatment of symptomatic intracranial atherosclerotic disease.

Higher risk of recurrent ischemic events in patients with intracranial in-stent restenosis

BACKGROUND AND PURPOSE

Reliable data concerning prognosis of patients with intracranial in-stent restenosis (ISR) is lacking. We prospectively studied long-term outcomes of patients with and without a catheter angiography-verified ISR.

METHODS

Between September 2001 and May 2009, 540 consecutive patients with symptomatic intracranial atherosclerosis received stenting treatment at our institute. Of them, 226 patients with 233 stented arteries had catheter angiography follow-up after stenting and were enrolled into this study. They were clinically followed up until the end of December 2011. Primary end point was ischemic stroke or transient ischemic attack in the territory of the stented artery after the catheter angiography follow-up. ISR was defined as a catheter angiography-verified stenosis of ≥50% within or immediately adjacent (within range of 3 mm) to the implanted stent.

RESULTS

During a mean follow-up of 38.9 months, 27 (11.6%, 27/233) primary end point events were recorded. The risk of primary end point in ISR group was higher compared with non-ISR group (21.1% [12/57] versus 8.5% [15/176]; hazard ratio, 2.94; 95% confidence interval, 1.37-6.30; P=0.005). Multivariable analysis showed that the ISR was an independent risk factor for the primary end point (hazard ratio, 2.79; 95% confidence interval, 1.20-6.49; P=0.017). The median occurrence time of primary end point was 9.9 (interquartile range, 5.0, 21.1) months in ISR group, earlier than that in non-ISR group (26.6 [13.1, 52.9] months; P=0.01).

CONCLUSIONS

In-stent restenosis after stenting of intracranial atherosclerosis is significantly associated with an increased risk and an earlier occurrence of recurrent ischemic events in the territory of the stented intracranial artery.

In-stent stenosis after stent-assisted coiling: incidence, predictors and clinical outcomes of 435 cases

BACKGROUND

Neuroform and Enterprise are widely used self-expanding stents designed to treat wide-necked intracranial aneurysms.

OBJECTIVE

To assess the incidence, clinical significance, predictors, and outcomes of in-stent stenosis (ISS).

METHODS

Angiographic studies and hospital records were retrospectively reviewed for 435 patients treated between 2005 and 2011 in our institution. A multivariable regression analysis was conducted to determine the predictors of ISS.

RESULTS

The Neuroform stent was used in 264 patients (60.7%) and the Enterprise in 171 patients (39.3%). A total of 11 patients (2.5%) demonstrated some degree of ISS during the follow-up period at a mean time point of 4.2 months (range, 2-12 months). The stenosis was mild (< 50%) in 8 patients (1.8%), moderate (50-75%) in 2 patients (0.5%), and severe (> 75%) in 1 patient (0.2%). No patients were symptomatic or required further intervention. There was complete ISS resolution in 2 patients, partial resolution in 2 patients, and no change in 5 patients on follow-up angiography. Patients developing ISS were significantly younger than those without ISS (40.3 vs. 54.9 years; P < .001). ISS rates were 2.7% with the Neuroform and 2.3% with the Enterprise stent (P = .6). In multivariable analysis, younger patient age (odds ratio = 0.92; P = .008), carotid ophthalmic aneurysm location (odds ratio = 7.7; P =0.01), and carotid terminus aneurysm location (odds ratio = 8.1; P = .009) were strong independent predictors of ISS. The type of stent was not a predictive factor.

CONCLUSION

Neuroform and Enterprise ISS is an uncommon, often transient, and clinically benign complication. Younger patients and those harboring anterior circulation aneurysms located at ophthalmic and carotid terminus locations are more likely to develop ISS.

Comparison of Drug-eluting Coronary Stents, Bare Coronary Stents and Self-expanding Stents in Angioplasty of Middle Cerebral Artery Stenoses

Objective

The purpose of this study is to investigate the results of treatment using stent-angioplasty for symptomatic middle cerebral arterial (MCA) stenosis and comparison of in-stent restenosis between drug-eluting stents (DES), bare metal coronary stents (BMS) and self-expanding stents (SES).

Materials and Methods

From Jan. 2007 to June. 2012, 34 patients (mean age ± standard deviation: 62.9 ± 13.6 years) with MCA stenosis were treated. Inclusion criteria were acute infarction or transient ischemic attacks (TIAs) and angiographically proven symptom related severe stenosis. Stents used for treatment were DES (n = 8), BMS (n = 13) and SES (n = 13). National Institutes of Health Stroke Scale (NIHSS) at admission was 2.5 ± 3.1 and mean stenosis rate was 79.0 ± 8.2%. Assessment of clinical and angiographic results was performed retrospectively.

Results

Among 34 patients, periprocedural complications occurred in four cases (11.8%), however, only two cases (6.0%) were symptomatic. All patients were followed clinically (mean follow-up period; 40.7 ± 17.7 months) and 31 were followed angiographically (91.2%. 13.4 ± 8.5 months). There was no occurrence of repeat stroke in all patients; however, mild TIAs related to restenosis occurred in three of 34 patients (8.8%). The mean NIHSS after stent-angioplasty was 1.7 ± 2.9 and 0.8 ± 1.1 at discharge. The modified Rankin score (mRS) at discharge was 0.5 ± 0.9 and 0.3 ± 0.8 at the last clinical follow-up. In-stent restenosis over 50% occurred in five of 31 angiographically followed cases (16.1%), however, all of these events occurred only in patients who were treated with BMS or SES. Restenosis rate was 0.0% in the DES group and 20.8% in the other group (p = 0.562); it did not differ between BMS and SES (2/11 18.2%, 3/13 23.1%, p = 1.000).

Conclusion

Stent-angioplasty appears to be effective for symptomatic MCA stenosis. As for restenosis, in our study, DES was presumed to be more effective than BMS and SES; meanwhile, the results did not differ between the BMS and SES groups.

Simulated biomechanical responses at a curved arterial segment after Wingspan Stent deployment in swine

OBJECTIVES

Endovascular treatment with the Wingspan Stent is frequently associated with in-stent restenosis at the curved portion, leading to late-phase stroke. To explore the cause of stroke complications after treatment with the Wingspan Stent, we simulated the biomechanical responses at a curved arterial segment using the finite element method.

METHODS

A Wingspan stent was deployed at a slightly curved ascending pharyngeal artery (APA) in swine. Several stress distributions modeling solid mechanics were analyzed with structural deformation. Histopathological analysis of the selected APA was assessed at 28 days after stenting.

RESULTS

Arterial straightening was simulated in this study. Both radial stress (RS) and circumferential stress (CS) concentrations increased at both stent ends. Marked lower axial stress (AS) concentration was observed at the outer wall of an arterial curvature. The proximal stent segment, ending in the curved portion, significantly impacted the solid mechanical environment. Eccentric neointimal hyperplasia was observed at the curved segment.

DISCUSSION

These results show that the Wingspan stent exaggerated the non-uniform stress distributions in a curved artery. The understanding of stent-arterial wall interactions is of value to identify the current limitations of intracranial stenting, and will help to improve this treatment methodology and future devices.

Disappearance of a small intracranial aneurysm as a result of vessel straightening and in-stent stenosis following use of an Enterprise vascular reconstruction device

In-stent stenosis after stent-assisted coil embolization is a rare but well-known complication. A 32-year-old woman with an unruptured wide-necked left internal carotid artery (ICA) terminus aneurysm and an ipsilateral very small anterior choroidal artery aneurysm underwent stent-assisted coil embolization for the ICA terminus aneurysm. The 4-month follow-up angiography revealed diffuse in-stent stenosis and disappearance of the untreated anterior choroidal artery aneurysm, retaining the patency of the anterior choroidal artery. To our knowledge, this is the first report to demonstrate the course of in-stent stenosis and disappearance of an untreated small intracranial aneurysm as a result. We report this unique case and discuss the interesting mechanism underlying this phenomenon, and also provide a review of the relevant literature.

Disappearance of a small intracranial aneurysm as a result of vessel straightening and in-stent stenosis following use of an Enterprise vascular reconstruction device

In-stent stenosis after stent-assisted coil embolization is a rare but well-known complication. A 32-year-old woman with an unruptured wide-necked left internal carotid artery (ICA) terminus aneurysm and an ipsilateral very small anterior choroidal artery aneurysm underwent stent-assisted coil embolization for the ICA terminus aneurysm. The 4-month follow-up angiography revealed diffuse in-stent stenosis and disappearance of the untreated anterior choroidal artery aneurysm, retaining the patency of the anterior choroidal artery. To our knowledge, this is the first report to demonstrate the course of in-stent stenosis and disappearance of an untreated small intracranial aneurysm as a result. We report this unique case and discuss the interesting mechanism underlying this phenomenon, and also provide a review of the relevant literature.

Wingspan Stenting for Intracranial Atherosclerotic Stenosis

BACKGROUND:

Intracranial atherosclerotic stenosis (ICAS) is responsible for 9% to 37% of ischemic strokes.

OBJECTIVE:

To evaluate the clinical outcome and risk factors for in-stent restenosis (ISR) after treatment of ICAS with a Wingspan stent.

METHODS:

Seventy-seven patients with 79 total target ICAS &gt; 60% (mean, 79.9 ± 8.4%; symptomatic ICAS, 96.2%) underwent attempted treatment with Wingspan stenting between March 2010 and March 2011. A retrospective review of the prospectively registered data was conducted to assess the risk factors for ISR and the clinical outcomes of these patients.

RESULTS:

The 30-day transient ischemic attack/stroke and death rates were 5.3% (95% confidence interval [CI], 0.1-10.5) and 0%, respectively. All patients but 1 were followed up clinically for a mean of 18.9 months (range, 12–23 months). During the period, cumulative transient ischemic attack/stroke and death rates were 8.1% (95% CI, 1.7-14.5) and 0%, respectively. Only 1 patient suffered a disabling stroke (subarachnoid hemorrhage), which was associated with retreatment of an ISR with a drug-eluting balloon-expandable stent. Follow-up angiography was available in 69 treated vessels (89.6%) at 3 to 24 months (median, 12 months). Binary ISR rate was 24.6%, of which 17.6% (3 of 17 cases) was symptomatic. Rapid balloon inflation (95% CI, 5.490-530.817) and longer length of stenosis (95% CI, 1.093-1.891) were independent risk factors for ISR.

CONCLUSION:

Wingspan stenting may be effective for appropriately selected ICAS patients. Rapid balloon inflation and longer lengths of stenosis were independent risk factors for ISR.

Intracranial atheromatous disease treatment with the Wingspan stent system: evaluation of clinical, procedural outcome and restenosis rate in a single-center series of 21 consecutive patients with acute and mid-term results

BACKGROUND

Intracranial atherosclerosis may be the underlying pathology in up to 15% of ischemic strokes, but may account for about 40% of strokes in some populations. After an ischemic event determined by intracranial atherosclerosis, patients have a 12% annual risk of stroke recurrence, mostly during the first year.

OBJECTIVE

To evaluate procedural safety, clinical outcome and restenosis rate of Wingspan stent placement.

METHODS

Twenty-one caucasoid patients were enrolled. Target patients were affected by high-grade, symptomatic, intracranial atherosclerotic lesions, were on antithrombotic therapy and at high stroke risk. All patients were treated with the Wingspan stent system.

RESULTS

Technical success resulted 100%, with all target lesions being reduced to <50%. No stroke or death were observed at 30. The mean percent of stenosis was reduced from a middle value of 84% to a middle value of 17% after stent placement. Medium follow-up was 19.5months (range 6-36months). No stroke or death occurred in any patient. None of the patients presented a <50% stent patency rate at follow-up.

CONCLUSIONS

The short-term results and follow up analysis provide evidence demonstrating the safety of the Wingspan system when used in high-risk patient population. Due to concerns regarding long-term stent patency and ischemic events occurrence emerged from clinical trials such as the SAMMPRIS, intracranial angioplasty and stent with the Wingspan system should be considered only for high risk patients in which it may be considered the only viable therapeutic option.

Symptomatic intracranial arterial disease: incidence, natural history, diagnosis, and management

Symptomatic intracranial arterial disease is associated with a high rate of recurrent ischemic events. The management of this condition is controversial, with some advocating medical therapy as a sole means of treatment and others recommending endovascular therapy in addition to best medical management. In rare cases, surgical intervention is considered. A thorough review of the available literature was performed, and treatment recommendations based on these data are provided.

Techniques and results: intracranial stenting

Recanalization rates with conventional pharmacologic thrombolysis and thrombectomy devices in the treatment of large-vessel occlusions are low. Moreover, these patients do not have favorable clinical outcomes. Better recanalization devices and approaches are needed. In this review, we describe current stents used in the intracranial circulation and their application in the treatment of acute ischemic stroke due to large-vessel occlusion.

Wingspan stents for the treatment of symptomatic atherosclerotic stenosis in small intracranial vessels: safety and efficacy evaluation

BACKGROUND AND PURPOSE

Until now, endovascular treatment of symptomatic atherosclerotic stenosis in small intracranial arteries (≤2.5 mm) was limited. We evaluated the safety and efficacy of the treatment by using Wingspan stents in arteries of this caliber.

MATERIALS AND METHODS

From March 2007 to July 2010, 53 symptomatic intracranial stenoses with narrowing of at least 50% in 53 patients were treated by using Wingspan stents. Clinical manifestations and imaging features were recorded.

RESULTS

The technical success rate was 98.1%. There were no serious complications, with the exception of 1 patient who experienced a small cerebral hemorrhage caused by perforation of microwire. Thirty-nine patients (74%) were available for follow-up imaging with DSA. ISR was documented in 13 of these patients, including 2 patients with symptomatic ISR. The median length of the vascular lesions was 5.39 mm, and patients whose vascular lesions were longer than 5.39 mm had a much higher incidence of ISR than patients whose vascular lesions were shorter than 5.39 mm (53% versus 15%, respectively). The median ratio of the reference artery diameter to the stent diameter was 0.78, and patients whose ratio was smaller than 0.78 had a much higher incidence of ISR than patients whose ratio was larger than 0.78 (53% versus 15%, respectively).

CONCLUSIONS

In our series, percutaneous transluminal angioplasty and stent placement of small intracranial arteries by using Wingspan stents was safe. The ISR rate was relatively high; most patients having ISR were asymptomatic. Further follow-up is needed to assess the long-term efficacy of this procedure.

Is there a future for endovascular treatment of intracranial atherosclerotic disease after Stenting and Aggressive Medical Management for Preventing Recurrent Stroke and Intracranial Stenosis (SAMMPRIS)?

The Stenting and Aggressive Medical Management for Preventing Recurrent Stroke and Intracranial Stenosis (SAMMPRIS) trial, a randomized clinical trial comparing aggressive medical management to stenting with aggressive medical management for symptomatic intracranial stenosis, was prematurely halted when a high rate of periprocedural events was found in the stent arm. The trial also demonstrated a high rate of stroke with medical management. This article explores possible reasons for these outcomes and discusses some weaknesses of the trial. Against this background endovascular therapy should continue to be explored in the treatment of this disease.

Current management of symptomatic intracranial stenosis

Intracranial arterial stenosis (IAS) is the cause of about 10% of all ischemic strokes in the United States, but may account for about 40% of strokes in some populations. After a stroke or transient ischemic attack due to IAS, patients face a 12% annual risk of recurrent stroke on medical therapy, with most strokes occurring in the first year. Warfarin is no better than aspirin in preventing recurrent strokes but poses a higher risk of serious bleeding and death. Groups with the highest risk of recurrent stroke are those with high-grade (≥ 70%) stenosis, those with recent symptom onset, those with symptoms precipitated by hemodynamic maneuvers, and women. Endovascular treatment of IAS is a rapidly evolving therapeutic option. Antiplatelet agents are currently recommended as the primary treatment for symptomatic IAS, with endovascular therapy reserved for appropriate high-risk cases refractory to medical therapy.

Endovascular treatment of symptomatic intracranial stenosis with the Wingspan stent system and Gateway PTA balloon: a multicenter series of 60 patients with acute and midterm results

Object

The limitations of the medical management of symptomatic intracranial arterial stenosis (SIAS) have encouraged the development of new strategies, such as endovascular treatment. In this study, the authors report and analyze a series of 63 endovascular procedures in which the Wingspan stent system was used.

Methods

Data from 60 patients presenting with refractory SIAS, treated in 5 French neurointerventional centers between September 2006 and August 2009, were retrieved. An angiogram was systematically obtained 6 months after the procedure and yearly thereafter. The clinical neurological status was assessed and reported using the modified Rankin scale at 1-month, 6-month, and 1-year follow-up visits.

Results

A total of 63 stenotic lesions was treated. The mean age of the patients was 65.3 years, and the mean diameter of the stenosis was 80.2%. Technical success was achieved in 95.2% of cases. The overall incidence of procedural complications was 20.6%, with a 4.8% rate of permanent postoperative morbidity and death. In-stent restenosis (ISR)/occlusion occurred in 11 cases (17.4%), of which 10 were asymptomatic and 9 were detected less than 1 year from the endovascular treatment. In 1 case, the patient presented with a recurrent transient ischemic attack and was treated again with angioplasty. The mean follow-up was 13.2 months.

Conclusions

Endovascular treatment of SIAS demonstrates a moderate risk of neurological complication. Nevertheless, considering the critical natural history of severe refractory lesions, this may be considered the first alternative in cases of failed medical therapy. Technical failure, residual stenosis, or in-stent restenosis did not lead to systematic recurrent stroke in this series, which suggests the importance of plaque stabilization and neoendothelialization.

The Modified Bose Method for the Endovascular Treatment of Intracranial Atherosclerotic Arterial Stenoses Using the Enterprise Stent

BACKGROUND

Balloon dilatation and deployment of a self-expanding stent is a safe treatment for intracranial atherosclerotic stenoses. The significant recurrence rate might be related to the high radial force of the Wingspan stent.

OBJECTIVE

To evaluate the procedural safety and stenosis recurrence rate by the use of a stent with reduced radial force (Enterprise).

METHODS

Two hundred nine atherosclerotic stenoses (189 patients) were treated (median age, 68 years; 132 male) in a single center. Lesion locations included internal carotid artery (n = 27), middle cerebral artery (n = 62), vertebral artery (n = 64), basilar artery (n = 55), and posterior cerebral artery (n = 1). Pre- and postmedication included acetylsalicylic acid and Clopidogrel for at least 12 months. Preprocedural and follow-up examinations included magnetic resonance imaging (MRI), neurological assessment, and digital subtraction angiography (6, 12, 26, and 52 weeks). Data registry included age, sex, normal vessel diameter, degree of stenosis, residual stenosis after stent, minimal in-stent diameter, and occurrence of ischemic symptoms during follow-up.

RESULTS

Median pre- and postprocedural stenosis rate was 65.4 ± 1% vs 25.1 ± 1%. Technical success rate was 100%. Major procedural complications occurred in 16 patients (8.1%). Combined neurological morbidity and mortality rate at 30 days was 2 patients (0.9%). In 174 stenoses (83%) angiographic follow-up was obtained (mean, 10.2 months). A restenosis (&gt;50%) was observed in 43 (24.7%) cases after 4.2 months (mean) with 4 (9.3%) symptomatic lesions. Incidence of recurrent ischemia related to the stented artery was 2.2% during 10.2 months of mean follow-up.

CONCLUSION

Undersized balloon angioplasty and deployment of an Enterprise stent is safe and effective for intracranial stenoses. Follow-up results were equal to or better than those reported for bare-metal balloon-expandable or self-expanding stents and yielded excellent protection from recurrent ischemia.

Drug eluting stents for symptomatic intracranial and vertebral artery stenosis

The use of bare metal stents (BMS) to prevent recurrent stroke due to stenosis of the cerebral vasculature is associated with high rates of restenosis. Drug-eluting stents (DES) may decrease this risk. We evaluated the performance of DES in a cohort of patients treated at our institution.Consecutive patients treated with DES were identified by a case log and billing records; data regarding procedural details, clinical outcome and angiographic follow-up was obtained by retrospective chart review.Twenty-six patients (27 vessels; 14 vertebral origin (VO); 13 intracranial) were treated. Stenosis was reduced from mean 81% to 8% at the VO and 80% to 2% intracranially. No strokes occurred in the first 24 hours after stenting or at any time point in the VO group during a mean follow-up period of nine months. Among patients with intracranial stents, stroke with permanent disability occurred within 30 days in 1/12 (8%) and after 30 days in 1/11 (9%) with clinical follow-up (mean follow-up, 14 months). Follow-up catheter angiography was obtained in 14/14 (100%) in the VO group at mean eight months and in 8/11 surviving patients (73%) at a mean of ten months after stenting in the intracranial group. The restenosis rate was 21% at the VO (3/14) and 38% (3/8) for intracranial stents. Restenosis at the VO was less frequent than might have been expected from reports utilizing BMS, however, overall restenosis rates appeared higher than previously reported for patients with intracranial DES and comparable with restenosis rates for intracranial BMS.