Primary Stenting of Intracranial Atherosclerotic Stenoses

Basilar artery stenting in hyperacute stroke: A systematic review of published cases

BACKGROUND AND PURPOSE

Basilar artery stenting is a rescue therapy in the management of hyperacute stroke. Published data on efficacy and safety are limited.

METHODS

A systematic review of published studies was performed in accordance with PRISMA guidelines. Inclusion criteria were adult patients with ischemic stroke with permanent basilar artery stent placement within 48 h of onset. Data were extracted by two independent reviewers. Additional cases from our institution were identified via a local stroke registry.

RESULTS

Of 212 screened articles, patient-level data was reported in 35 studies (87 individuals) and six additional patients were included from our registry. Patients (n = 93, 63 % male; median age 64) most often presented with mid-basilar occlusion (52 %) and 76 % received treatment within 12 hours of onset. Favorable angiographic results occurred in 67 %. The final modified Rankin Scale score (mRS) was 0-3 for 56 % of patients; mortality was 29 %. Those with complete flow post-procedure were more likely to have a final mRS of 0-3 (p = 0.05).

CONCLUSIONS

In 93 cases of basilar stenting in hyperacute stroke, favourable angiographic and functional outcomes were reported in 67 % and 56 % of patients, respectively. International multicenter registries are required to establish benefit and identify patient and technical factors that predict favorable outcomes.

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.

Three cases of middle cerebral artery occlusion emergently revascularized with a balloon-expandable coronary bare stent after intravenous tissue plasminogen activator

BACKGROUND

Revascularization with emergency stent placement in patients with acute middle cerebral artery occlusion is still controversial in Japan.

METHODS

We placed balloon-expandable coronary bare stents in 3 patients in whom revascularization was not obtained after intravenous tissue plasminogen activator therapy (IV t-PA) for acute ischemic stroke (middle cerebral artery M1 occlusion).

RESULTS

Patient 1 was an 87-year-old woman with left hemiplegia. Her National Institutes of Health Stroke Scale score (NIHSS) was 12, and her magnetic resonance imaging diffusion-weighted image Alberta Stroke Programme Early Computed Tomography Score (MRI DWI-ASPECTS) was 8. Adequate revascularization was not obtained with IV t-PA and adjunctive percutaneous transluminal angioplasty (PTA) for right M1 occlusion, and a stent was placed 368 minutes after onset. Her Thrombolysis in Myocardial Infarction Trial (TIMI) score was 2. After 90 days, her modified Rankin scale (mRS) score was 4. Patient 2 was a 65-year-old woman with left hemiplegia. Her NIHSS score was 16, and MRI DWI-ASPECTS was 9. A stent was placed 337 minutes after onset after IV t-PA and adjunctive PTA for right M1 occlusion. Her TIMI score was 3. After 90 days, her mRS score was 3. Patient 3 was a 61-year-old woman with left hemiplegia. Her NIHSS score was 18, and MRI DWI-ASPECTS score was 7. Arterial dissection was found after IV t-PA and adjunctive PTA for the right M1 occlusion, so a stent was placed 312 minutes after onset. Her TIMI score was 2. After 90 days, her mRS score was 0.

CONCLUSIONS

Revascularization with emergency stent placement seems likely to be successful in patients with acute middle cerebral artery occlusion, but clinical symptoms do not always improve in some cases and care is needed in selecting patients for the procedure.

Stenting for the treatment of high-grade intracranial stenoses

To date, evidence to recommend endovascular treatment in patients with intracranial stenoses is lacking. Recently, the introduction of self-expanding stents (Wingspan Stent System) aroused considerable expectations in their employ for stroke prevention. We report a single-center experience of percutaneous transluminal angioplasty and stenting in a series of consecutive patients with intracranial stenoses and compare the safety and performance of balloon-mounted stents versus self-expanding stent systems (Wingspan). Thirty-four patients with 39 severe (>70%) intracranial stenoses were treated during a 6-year period. An independent stroke neurologist collected data about intra and periprocedural complications and short-term outcome. We considered as endpoint measures (1) any 30-day stroke or death (2) any major 30-day complication and (3) procedure technical success. Technical success was achieved in all patients. No vessel dissection or ruptures were observed. The 30-day stroke/death rate was 17.9%. Five ischemic strokes in the territory of treated vessels and two intracranial hemorrhages occurred respectively within 24 h and 5 days after endovascular treatment. Three (17.6%) patients of Wingspan treated group and four (18.2%) of the patients treated with different stent systems had unfavorable outcome. Our study confirms that endovascular treatment can be performed with a high technical success rate, even though the safety of these devices has still to be demonstrated.

COMPARISON BETWEEN PRIMARY ANGIOPLASTY AND STENT PLACEMENT FOR SYMPTOMATIC INTRACRANIAL ATHEROSCLEROTIC DISEASE

OBJECTIVE

To compare the short- and long-term rates of stroke-and/or-death associated with primary angioplasty alone and angioplasty with stent placement using a meta-analysis of published studies. Both primary angioplasty alone and angioplasty with stent placement have been proposed as treatment strategies for symptomatic intracranial atherosclerotic disease to reduce the risk of stroke-and/or-death with best medical treatment alone. However, it remains unclear which of these endovascular techniques offers the best risk reduction.

METHODS

We identified pertinent studies published between January 1980 and May 2008 using a search on PubMed and Cochrane libraries, supplemented by a review of bibliographies of selected publications. The incidences of stroke-and/or-death were estimated for each report and pooled for both angioplasty alone and angioplasty with stent placement at 1 month and 1 year postintervention and then compared using a random-effects model. The association of year of publication and 1-year incidence of stroke-and/or-death was analyzed with meta-regression.

RESULTS

After applying our selection criteria, we included 69 studies (33 primary angioplasty-alone studies [1027 patients] and 36 studies of angioplasty with stent placement [1291 patients]) in the analysis. There were a total of 91 stroke-and/or-deaths reported in the angioplasty-alone–treated group (8.9%; 95% confidence interval [CI], 7.1%–10.6%), compared with 104 stroke-and/or-deaths in the angioplasty-with-stent–treated group (8.1%; 95% CI, 6.6%–9.5%) during a 1-month period (relative risk [RR], 1.1; P = 0.48). The pooled incidence of 1-year stroke-and/or-death in patients treated with angioplasty alone was 19.7% (95% CI, 16.6%–23.5%), compared with 14.2% (95% CI, 11.9%–16.9%) in the angioplasty-with-stent–treated patients (RR, 1.39; P = 0.009). The incidence of technical success was 79.8% (95% CI, 74.7%–84.8%) in the angioplasty-alone group and 95% (95% CI, 93.4%–96.6%) in the angioplasty-with-stent–treated group (RR, 0.84; P < 0.0001). The pooled restenosis rate was 14.2% (95% CI, 11.8–16.6%) in the angioplasty-alone group, as compared with 11.1% (95% CI, 9.2%–13.0%) in the angioplasty-with-stent–treated group (RR, 1.28; P = 0.04). There was no effect of the publication year of the studies on the risk of stroke-and/or-death.

CONCLUSION

Risk of 1-year stroke-and/or-death and rate of angiographic restenosis may be lower in symptomatic intracranial atherosclerosis patients treated by angioplasty with stent placement compared with patients treated by angioplasty alone.

Reporting standards for angioplasty and stent-assisted angioplasty for intracranial atherosclerosis

BACKGROUND AND PURPOSE

Intracranial cerebral atherosclerosis causes ischemic stroke in a significant number of patients. Technological advances over the past 10 years have enabled endovascular treatment of intracranial atherosclerotic stenosis. The number of patients treated with angioplasty or stent-assisted angioplasty for this condition is increasing. Given the lack of universally accepted definitions, the goal of this document is to provide consensus recommendations for reporting standards, terminology, and written definitions when reporting clinical and radiological evaluation, technique, and outcome of endovascular treatment using angioplasty or stent-assisted angioplasty for stenotic and occlusive intracranial atherosclerosis.

SUMMARY OF REPORT

This article was written under the auspices of Joint Writing Group of the Technology Assessment Committee, Society of NeuroInterventional Surgery, Society of Interventional Radiology; Joint Section on Cerebrovascular Neurosurgery of the American Association of Neurological Surgeons and Congress of Neurological Surgeons; and the Section of Stroke and Interventional Neurology of the American Academy of Neurology. A computerized search of the National Library of Medicine database of literature (PubMed) from January 1997 to December 2007 was conducted with the goal to identify published endovascular cerebrovascular interventional data in stenotic intracranial atherosclerosis that could be used as benchmarks for quality assessment. We sought to identify those risk adjustment variables that affect the likelihood of success and complications. This document offers the rationale for different clinical and technical considerations that may be important during the design of clinical trials for endovascular treatment of intracranial stenotic and occlusive atherosclerosis. Included in this guidance document are suggestions for uniform reporting standards for such trials. These definitions and standards are primarily intended for research purposes; however, they should also be helpful in clinical practice and applicable to all publications.

CONCLUSION

In summary, the definitions proposed represent recommendations for constructing useful research data sets. The intent is to facilitate production of scientifically rigorous results capable of reliable comparisons between and among similar studies. In some cases, the definitions contained here are recommended by consensus of a panel of experts in this writing group for consistency in reporting and publication. These definitions should allow different groups to publish results that are directly comparable.

Reporting Standards for Angioplasty and Stent-Assisted Angioplasty for Intracranial Atherosclerosis

Background and Purpose— Intracranial cerebral atherosclerosis causes ischemic stroke in a significant number of patients. Technological advances over the past 10 years have enabled endovascular treatment of intracranial atherosclerotic stenosis. The number of patients treated with angioplasty or stent-assisted angioplasty for this condition is increasing. Given the lack of universally accepted definitions, the goal of this document is to provide consensus recommendations for reporting standards, terminology, and written definitions when reporting clinical and radiological evaluation, technique, and outcome of endovascular treatment using angioplasty or stent-assisted angioplasty for stenotic and occlusive intracranial atherosclerosis.

Summary of Report— This article was written under the auspices of Joint Writing Group of the Technology Assessment Committee, Society of NeuroInterventional Surgery, Society of Interventional Radiology; Joint Section on Cerebrovascular Neurosurgery of the American Association of Neurological Surgeons and Congress of Neurological Surgeons; and the Section of Stroke and Interventional Neurology of the American Academy of Neurology. A computerized search of the National Library of Medicine database of literature (PubMed) from January 1997 to December 2007 was conducted with the goal to identify published endovascular cerebrovascular interventional data in stenotic intracranial atherosclerosis that could be used as benchmarks for quality assessment. We sought to identify those risk adjustment variables that affect the likelihood of success and complications. This document offers the rationale for different clinical and technical considerations that may be important during the design of clinical trials for endovascular treatment of intracranial stenotic and occlusive atherosclerosis. Included in this guidance document are suggestions for uniform reporting standards for such trials. These definitions and standards are primarily intended for research purposes; however, they should also be helpful in clinical practice and applicable to all publications.

Conclusion— In summary, the definitions proposed represent recommendations for constructing useful research data sets. The intent is to facilitate production of scientifically rigorous results capable of reliable comparisons between and among similar studies. In some cases, the definitions contained here are recommended by consensus of a panel of experts in this writing group for consistency in reporting and publication. These definitions should allow different groups to publish results that are directly comparable.

Subacute Stent Thrombosis in Intracranial Stenting

Background and Purpose— We sought to determine the safety of intracranial stenting with respect to subacute stent thrombosis in patients being treated with standardized antiplatelet therapy.

Methods— We retrospectively evaluated the outcome of primary intracranial stenting of atherosclerotic stenoses and of stenting in coil embolization procedures in 67 patients. We focused on those cases that led to subacute stent thrombosis even though the patients had been treated with standardized antiplatelet therapy before, during, and after stent placement. Patient age ranged from 19 to 78 years. In 33 patients, stents were placed for treatment of atherosclerotic stenoses; in the remaining 34 patients, stents were placed to assist coiling of aneurysms. The patients in this study were treated between January 2003 and August 2007.

Results— Of the total 67 patients initially treated successfully by intracranial stenting, 7 patients developed subacute stent thrombosis. Of these 7 patients, 3 received stent placement into the basilar artery because of an underlying stenosis; in 1 patient, a stenosis of the M1 segment of the middle cerebral artery was treated. In 3 patients, aneurysms of the anterior cerebral artery, the posterior inferior cerebellar artery, and the basilar artery were treated by stent-assisted coil embolization. In 4 of the 7 patients with subacute thrombosis, recanalization of stents by local application of recombinant tissue-type plasminogen activator was successful.

Conclusions— Intracranial stenting can lead to subacute stent thrombosis, even in patients who are treated with standardized antiplatelet therapy. Such complications have been described for patients after coronary artery stenting, but to our knowledge, no one has reported on a comparable number of cases of intracranial stenting procedures. In certain clinical scenarios, local thrombolysis with recombinant tissue-type plasminogen activator is an important treatment option to deal with subacute stent thrombosis.

A systematic review on outcome after stenting for intracranial atherosclerosis

BACKGROUND AND PURPOSE

Angioplasty and stenting is increasingly being used for the treatment of intracranial stenoses. Based on a literature search (01/1998 to 04/2008) we sought to determine the immediate and long-term outcomes, as well as the durability of this procedure.

SUMMARY OF REVIEW

We identified 31 studies dealing with 1177 procedures, which had mainly been performed in patients with a symptomatic (98%) intracranial high-grade stenosis (mean: 78+/-7%) at high technical success rates (median: 96%; interquartile range [IQR]: 90% to 100%). The periprocedural minor or major stroke and death rates ranged from 0% to 50% with a median of 7.7% (IQR: 4.4% to 14.3%). Periprocedural complications were significantly higher in the posterior versus the anterior circulation (12.1%, versus 6.6%, P<0.01, odds ratio [OR]: 1.94, 95% confidence interval [CI]: 1.21 to 3.10), but did not differ between patients treated with a balloon-mounted (n=906) versus those who had been treated with a self-expandable stent (n=271; 9.5% versus 7.7%, P=0.47, OR: 1.15, CI:0.76 to 2.05). Restenosis >50% occurred more frequently after the use of a self-expandable stent (16/92; 17.4%, mean follow-up time: 5.4 months) than a balloon-mounted stent (61/443; 13.8%, mean follow-up time: 8.7 months; P<0.001, log-rank test).

CONCLUSIONS

Although intracranial stenting appears to be feasible, adverse events vary widely. Against the background of the results of this review yielding a high rate of restenoses and no clear impact of new stent devices on outcome, the widespread application of intracranial stenting outside the setting of randomized trials and in inexperienced centers currently does not seem to be justified.

Critical appraisal of medical devices in the management of cerebrovascular disease

Medical devices may revolutionize the management of acute ischemic stroke and prevention of recurrent events. By comparison with pharmaceuticals, the device approval process and subsequent application of these devices in stroke treatment is founded on a paucity of Class I evidence-based clinical trial data. Thromboembolectomy for acute stroke, stenting of cervical or cerebral arteries for stroke prevention, and percutaneous closure of patent foramen ovale for prevention or recurrent cerebral ischemia are being done with an ever-increasing frequency despite few, if any, randomized clinical trials to confirm the appropriateness of the interventions. The current basis, or lack thereof, for these interventions for cerebrovascular disease is therefore discussed. As such, a critical appraisal of the available clinical data does not support widespread use of medical devices at this time outside of well-designed clinical trials.

The current role of 1.5T non-contrast 3D time-of-flight magnetic resonance angiography to detect intracranial steno-occlusive disease

BACKGROUND/PURPOSE

This study was performed to evaluate the role of non-contrast 3D time-of-flight (TOF) magnetic resonance angiography (MRA) to detect and quantify intracranial steno-occlusive disease.

METHODS

Between April 2004 and January 2006, 45 patients with both 1.5T TOF MRA and digital subtraction angiography (DSA) performed within a 30-day interval were included. We evaluated the following intracranial arterial segments: petrous internal carotid artery (ICA), cavernous ICA, supraclinoid ICA, M1 of middle cerebral artery, A1 of anterior cerebral artery, P1 of posterior cerebral artery, basilar artery, and distal vertebral artery. In total, 675 arterial segments were evaluated and categorized as negative, moderate-1 (3049% stenosis), moderate-2 (5069%), severe (7099% stenosis, including gap sign on MRA), and occlusion.

RESULTS

The sensitivity and specificity of TOF MRA for > 29% stenosis and > 49% stenosis were 94%, 96% and 95%, 96%, respectively; while sensitivity and specificity for occlusion lesions were both 100%. However, 44 segments (37% of diseased segments) were overestimated by MRA, including 20 false-positive stenoses (which occurred in 10 [22%] patients) and 24 overestimated stenosis degree. The gap sign as severe stenosis only showed about 21% sensitivity and 41% specificity. Seven lesions were underestimated by MRA: three arterial segments were out of the field of MRA examination, and four were moderate-1stenosis on DSA.

CONCLUSION

TOF MRA has high sensitivity and specificity in detecting all categories of stenosis degree and occlusion. However, it tends to overestimate lesions. Therefore, MRA can be considered as a screening study. Confirmation with other studies is recommended in doubtful cases.

Management of Vertebral Stenosis Complicated by Presence of Acute Thrombus

A 44-year-old male presented with multiple punctate acute infarcts of the vertebrobasilar circulation and a computed tomographic angiogram showing stenosis of the right vertebral origin. A digital subtraction angiogram demonstrated a new intraluminal filling defect at the origin of the stenotic vertebral artery where antegrade flow was maintained. This filling defect was accepted to be an acute thrombus of the vertebral origin, most likely due to rupture of a vulnerable plaque. The patient was treated with intravenous heparin. A control angiogram revealed dissolution of the acute thrombus under anticoagulation and the patient was treated with stenting with distal protection. Diffusion-weighted magnetic resonance imaging demonstrated no additional acute ischemic lesions. We were unable to find a similar report in the English literature documenting successful management of an acute vertebral ostial thrombus with anticoagulation. Anticoagulation might be considered prior to endovascular treatment of symptomatic vertebral stenoses complicated by the presence of acute thrombus.

Angioplasty for intracranial artery stenosis

BACKGROUND

Intracranial artery stenosis causes up to 10% of all ischaemic strokes. The rate of recurrent vascular ischaemic events is very high. Angioplasty with or without stent placement is a feasible procedure to dilate the vessel affected. However, its safety and efficacy have not been systematically studied.

OBJECTIVES

To determine the efficacy and safety of angioplasty combined with best medical treatment compared with best medical treatment alone in patients with acute ischaemic stroke or transient ischaemic attack (TIA) resulting from intracranial artery stenosis for preventing recurrent ischaemic strokes, death, and vascular events.

SEARCH STRATEGY

We searched the Cochrane Stroke Group Trials Register (last searched March 2006). In addition we searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 1, 2006), MEDLINE (1966 to March 2006), EMBASE (1980 to February 2006) and Science Citation Index (1945 to March 2006). To identify further published, unpublished and ongoing trials we searched reference lists of relevant articles and contacted authors and experts in the field.

SELECTION CRITERIA

Randomised or otherwise controlled studies comparing best medical care plus angioplasty of the intracranial cerebral arteries, with or without stent placement, with best medical care alone. Studies were only included if data for clinical significant endpoints such as recurrent ischaemic stroke, haemorrhagic stroke and death were available.

DATA COLLECTION AND ANALYSIS

Two review authors selected trials for inclusion, and independently assessed trial quality and extracted data. Calculation of relative treatment effects with subgroup analysis was done if possible.

MAIN RESULTS

No randomised controlled trials were found. There were 79 articles of interest consisting of open-label case series with three or more cases. The safety profile of the procedure showed an overall perioperative rate of stroke of 7.9% (95% confidence intervals (CI) 5.5% to 10.4%), perioperative death of 3.4% (95% CI 2.0% to 4.8%), and perioperative stroke or death of 9.5% (95% CI 7.0% to 12.0%). No comments can be made on the effectiveness of the procedure.

AUTHORS' CONCLUSIONS

At present there is insufficient evidence to recommend angioplasty with or without stent placement in routine practice for the prevention of stroke in patients with intracranial artery stenosis. The descriptive studies show that the procedure is feasible although carries a significant morbidity and mortality risk. Evidence from randomised controlled trials is needed to assess the safety of angioplasty and its effectiveness in preventing recurrent stroke.

Stenting of vertebrobasilar arteries in symptomatic atherosclerotic disease and acute occlusion: case series and review of the literature

PURPOSE

Two of three patients with vertebrobasilar stroke harbor a stenosis of the vertebral or basilar arteries. The best treatment for secondary prophylaxis in vertebrobasilar occlusive disease has not been defined. In patients with high-grade stenoses, and especially those refractory to medication, stenting offers the chance to restore normal flow and prevent major strokes.

METHODS

We provide data regarding outcome and complications on 20 consecutive patients who underwent vertebrobasilar stenting at our institution (9 V0, 2V3, 5 V4, and 4 basilar artery lesions). Furthermore, we provide a comprehensive overview of the literature on >600 cases of vertebrobasilar stenting, including all published cases up to 2005.

RESULTS

Primary interventional success was achieved in all cases, with a mean residual stenosis of 3% +/- 4% in V0, 5% +/- 4% in V3/4, and 7% +/- 3% in basilar artery lesions. No peri-interventional neurologic complications and no transient ischemic attack or stroke at follow-up were noted in patients with vertebral ostial lesions, whereas two transient and three permanent clinical deteriorations occurred in patients with V4 or basilar artery lesions, some of which had presented with acute stroke. Patency rate was 100% at the last examination. According to published data on proximal vertebral artery stenting, mortality is 0.3%, the rate of neurologic complications is 5.5%, and the risk of posterior stroke at follow-up is 0.7%. Interventions for distal vertebral or basilar artery disease carry a 3.2% mortality risk, a 17.3% risk for neurologic complications and a 2% risk for stroke at follow-up.

CONCLUSIONS

Stenting of the vertebral origin can be performed safely and with a low rate of cerebral ischemic events at follow-up, although restenosis may occur. Larger comparative trials are needed. Treatment decisions in distal vertebrobasilar disease have been made on an individual basis.

Treatment of intracranial stenoses using the Neuroform stent system: initial experience in five cases

INTRODUCTION

We assessed the technical feasibility of balloon-assisted angioplasty with consecutive stenting using a flexible, self-expanding neurovascular stent for the treatment of intracranial arteriosclerotic vascular stenoses.

METHODS

Five consecutive patients with symptomatic drug-resistant stenoses of the intracranial internal carotid artery (ICA) or the main stem of the middle cerebral artery (MCA) were treated by balloon-assisted angioplasty with consecutive stenting using the Neuroform stent system.

RESULTS

Balloon dilatation of the stenoses and consecutive stent placement with complete coverage of the stenoses was feasible in all patients. One patient suffered acute thrombosis distally to the stented vessel segment which was successfully treated by fibrinolysis, and one patient suffered acute subarachnoid and parenchymal hemorrhage probably due to vessel perforation. In the other three patients, no complications occurred during or immediately after angioplasty. All patients were free of further ischemic events up to the 6-month follow-up.

CONCLUSION

Our findings demonstrate that the Neuroform stent system can used successfully for the treatment of intracranial stenoses of the ICA and the main stem of the MCA. Although immediate angiographic results are promising, long-term angiographic and clinical follow-up is essential to demonstrate long-term outcome.