Vertebral artery stenosis in the Basilar Artery International Cooperation Study (BASICS): prevalence and outcome

Impact of tortuosity of the V1-segment vertebral artery on mechanical thrombectomy

Tortuosity of the vasculature poses challenges to mechanical thrombectomy (MT); however, only a few studies have reported the impact of vertebral artery (VA) tortuosity on MT. The present study aimed to investigate the impact of tortuosity of the V1-segment VA on MT in patients with acute vertebrobasilar artery occlusion (AVBAO). The patients diagnosed with AVBAO and treated with MT in the Stroke Center of Xijing Hospital from November 2019 to March 2022 were analyzed retrospectively. According to the tortuosity of V1-segment VA, patients were divided into tortuous (coiling and kinking) and non-tortuous groups (straight, single-arc, and multi-arc). A binary logistic regression model was established to analyze the association between the tortuosity of V1-segment VA and successful reperfusion (mTICI ≥ 2b), neurological improvement at 7 days, favorable and poor outcome at 90 days, and symptomatic intracranial hemorrhage (ICH) within 24 h. After adjustment for age, baseline National Institute of health stroke scale (NIHSS) score and puncture-to-recanalization time, the impact of tortuosity of the V1-segment VA on outcomes was analyzed. After screening, 35 patients were enrolled in this study. The overall rate of successful reperfusion was 74.3% (26/35), and 40% (14/34) patients achieved favorable outcomes at 90 days. Subsequently, 15/35 (42.9%) patients were included in the tortuous group, and the remaining 20 patients comprised the non-tortuous group. After adjustment for age, baseline NIHSS score, and puncture-to-recanalization time, the rate of 90-day favorable outcome in the tortuous group was significantly lower than that of the non-tortuous group (20% vs. 57.9%, P = 0.034), while the rates of reperfusion (80% vs. 73.7%) and 7-day neurological improvement (33.3% vs. 36.8%) were similar between the two groups. The incidence of 24-h symptomatic ICH in the tortuous group was higher than that in the non-tortuous group (26.7% vs. 15.8%), albeit not significantly. In patients with AVBAO, tortuosity of the V1-segment VA was negatively associated with favorable outcomes 90 days after MT.

The short-term outcome of intracranial stenosis with distal thrombosis treated with balloon-assisted tracking

Background and purposes

Treating intracranial stenosis with distal thrombosis (IS&DT) using traditional mechanical thrombectomy (MT) techniques has proven challenging. This study aimed to summarize the experience of utilizing the balloon-assisted tracking (BAT) technique for IS&DT.

Methods

Demographic and morphologic characteristics of patients with IS&DT were collected for this study. The BAT technique, involving a half-deflated balloon outside the intermediate catheter tip, was used in all patients to navigate through the proximal stenosis. Various parameters were recorded, including the sequence of vascular reperfusion, the puncture-to-reperfusion time (PRT), the residual stenosis rate, and the occurrence of re-occlusion. The thrombolysis in cerebral infarction (TICI) scale was used to assess the reperfusion of intracranial vessels, with a TICI score of ≥2b considered as successful perfusion. The clinical status of patients was evaluated at three time points: pre-procedure, post-procedure, and at discharge using the modified Rankin score (mRS).

Results

In this study, a total of 10 patients were diagnosed with IS&DT, consisting of 9 male patients (90.0%) and 1 female patient (10.0%). The patients' mean age was 63.10 years (ranging from 29 to 79 years). The mean National Institute of Health Stroke Scale (NIHSS) score before treatment was 24.3 (ranging from 12 to 40), indicating the severity of their condition. Following the procedure, all patients achieved successful reperfusion with a thrombolysis in cerebral infarction (TICI) score of ≥2b. The average puncture-to-reperfusion time (PRT) was 51.8 min (ranging from 25 to 100 min), indicating the time taken for the procedure. During the perioperative period, three patients (30.0%) experienced complications. One patient had hemorrhage, while two patients had contrast extravasation. Among these cases, only the patient with hemorrhage (10%) suffered from a permanent neurological function deficit. At discharge, the patient's condition showed improvement. The mean NIHSS score decreased to 13.2 (ranging from 1 to 34), indicating a positive response to treatment. The mean mRS score at discharge was 3.2 (ranging from 1 to 5), showing some level of functional improvement.

Conclusion

In conclusion, the use of the balloon-assisted tracking (BAT) technique for treating intracranial stenosis with distal thrombosis (IS&DT) showed promising results. However, a moderate rate of perioperative complications was observed, warranting further investigation and refinement of the procedure.

[Vertebrobasilar insufficiency caused by extravasal compression of the vertebral artery in the second segment]

OBJECTIVE

To develop indications for surgical treatment for positional disorders of blood flow in the vertebral-basilar territory caused by the damage to the V2-V3 segment of the vertebral artery (VA).

MATERIAL AND METHODS

One hundred and fourteen patients with systemic and non-systemic dizziness were studied. To assess the state of the VA, blood circulation of the posterior cranial fossa and the base of the brain, ultrasound duplex scanning of blood vessels, selective angiography, MRI, single photon emission computed tomography (SPECT) of the brain and neuropsychological testing were performed. Patients were divided into three groups according to the severity of clinical manifestations of vertebrobasilar insufficiency (VBI).

RESULTS

According to ultrasound data, patients of the third group with severe VBI had signs of extravasal compression in 94.3% of cases. In the same group, there was an increase in the systolic-diastolic (S/D) ratio by more than 2.5-3 times, as well as an increase in the resistive index (RI) by more than 1.75 units and pulsation index (PI) more than 2.2 units in V2-V3 segments of VA. In 42.9% of patients of the third group, zones of a decrease in the accumulation of 99mTc-ECD by more than 20% were found in the occipital region during the De Klein test. A direct correlation was established between the clinical manifestations of VBI and a decrease in perfusion during SPECT by 20% or more with the De Klein test (r=0.7). We developed an algorithm for diagnosing high-grade VBI with subsequent identification of a causal relationship with extravasal component effects on VA in the second segment. Indications for surgical intervention were determined in 33 patients with clinical manifestations of blood flow decompensation in the posterior cranial fossa.

CONCLUSION

Decreased blood flow velocity in the vertebral or basilar artery by more than 50% with a decrease in PI, breath holding index <0.7 in the hypercapnic test, and no increase in blood flow velocity in a phototest and, in addition, the >20% defect of 99mTc-ECD accumulation in the posterior parts of the brain during SPECT with a De Klein test are the criteria for decompensation of blood flow in the vertebral-basilar territory, requiring surgical correction.

Etiology-Related Outcome of Endovascular Therapy in Posterior Circulation Stroke Compared to Anterior Circulation Stroke

Background and Purpose

We investigated the impact of stroke etiology on the endovascular treatment (EVT) procedure and clinical outcome of posterior circulation stroke (PCS) patients with EVT compared to anterior circulation stroke (ACS) patients.

Methods

We retrospectively analyzed ischemic stroke patients who underwent EVT between January 2012 and December 2020. Enrolled ACS and PCS patients were compared according to etiologies (intracranial arterial steno-occlusion [ICAS-O], artery-to-artery embolic occlusion [AT-O], and cardioembolic occlusion [CA-O]). EVT procedure and favorable clinical outcomes at 3 months (modified Rankin Scale 0–2) were compared between the ACS and PCS groups for each etiology.

Results

We included 419 patients (ACS, 346; PCS, 73) including 88 ICAS-O (ACS, 67; PCS, 21), 66 AT-O (ACS, 50; PCS, 16), and 265 CA-O (ACS, 229; PCS, 36) patients in the study. The onset-to-recanalization time was longer in the PCS group than in the ACS group (median 628.0 minutes vs. 421.0 minutes, P=0.01). In CA-O patients, the door-to-puncture time was longer, whereas the puncture-to-recanalization time was shorter in the PCS group than in the ACS group. The proportions of successful recanalization and favorable clinical outcomes were similar between the ACS and PCS groups for all three etiologies. Low baseline National Institutes of Health Stroke Scale (NIHSS) scores and absence of intracerebral hemorrhage at follow-up imaging were associated with favorable clinical outcomes in both groups, whereas successful recanalization (odds ratio, 11.74; 95% confidence interval, 2.60 to 52.94; P=0.001) was only associated in the ACS group.

Conclusions

The proportions of successful recanalization and favorable clinical outcomes were similar among all three etiologies between PCS and ACS patients who underwent EVT. Initial baseline NIHSS score and absence of hemorrhagic transformation were related to favorable outcomes in the PCS and ACS groups, whereas successful recanalization was related to favorable outcomes only in the ACS group.

Non-invasive Detection of Diffuse Intracranial Vertebrobasilar Artery Stenosis: A Prospective Comparison with Digital Subtraction Angiography

The aim of this study was to prospectively evaluate diffuse intracranial vertebrobasilar artery stenosis by ultrasonic examination with digital subtraction angiography as the reference. Five hundred forty-one vertebrobasilar arteries with a normal lumen or intracranial stenosis were enrolled. Peak systolic velocity, mean flow velocity and end-diastolic velocity (EDV) at the intracranial vertebrobasilar arteries and extracranial vertebral arteries (VAs) were measured. The resistance index (RI) at extracranial VAs and the difference between the RI of extracranial VAs and the RI of the extracranial internal carotid artery (RI_ica) were calculated. Compared with normal arteries, all stenotic arteries were divided into the high-velocity group (focal stenosis, multiple-segment stenosis and multiple-artery stenosis) and low-velocity group (critical stenosis and long stenosis). The consistency between ultrasonic examination and digital subtraction angiography for evaluation of vertebrobasilar arteries with multiple-segment stenosis and multiple-artery stenosis was not favorable when applying the widely used Stroke Outcomes and Neuroimaging of Intracranial Atherosclerosis criteria (κ = 0.442 and 0.438, respectively). The optimal low-velocity criteria for identifying intracranial vertebrobasilar arteries with critical stenosis and long stenosis were determined by receiver operating characteristic curve analysis and were as follows: EDV ≤15 cm/s and RI ≥0.68 at the extracranial VA and RIica ≥0.10.

Revascularization of vertebrobasilar tandem occlusions: a meta-analysis

PURPOSE

To investigate the difference in mechanical thrombectomy (MT) outcomes between vertebrobasilar tandem occlusion (VBTO) and isolated basilar artery (BA) occlusion (non-VBTO) and the difference in rates of successful recanalization between the clean-road and dirty-road pathways, in VBTO.

METHODS

We conducted a meta-analysis after searching PubMed, EMBASE, and Google Scholar databases as of April 2021. We only included adult patients who underwent MT to treat acute ischemic stroke (AIS) due to VBTO, and the following outcomes should be reported: successful recanalization, functional outcome at 90 days, and symptomatic intracerebral hemorrhage (sICH). The main effect size measures were odds ratio and risk difference, and the software used was RevMan 5.4.

RESULTS

The analysis included 81 VBTO and 324 non-VBTO patients (seven studies). We found no significant difference regarding 3 m functional independence [4 studies: OR = 1.71 (95% CI, 0.54, 5.43), I² = 75%], 3 m mortality [4 studies: OR = 1.62 (95% CI, 0.62, 4.25), I² = 66%], sICH [4 studies: OR = 1.71 (95% CI, 0.67, 4.39), I² = 0%], and successful recanalization [3 studies: OR = 0.81 (95% CI, 0.12, 5.57), I² = 80%]. A subgroup analysis of 118 VBTO patients (five studies) showed no significant difference in successful recanalization between clean-road and dirty-road pathways [RD = 0.07 (95% CI, - 0.09, 0.24), I² = 40%].

CONCLUSION

The results of this meta-analysis support the use of MT for AIS patients with VBTO. In VBTO patients, none of the clean-road or dirty-road pathways proved to be superior to the other.

Nomogram to Predict Poor Outcome after Mechanical Thrombectomy at Older Age and Histological Analysis of Thrombus Composition

An easy scoring system to predict the risk of poor outcome after mechanical thrombectomy among the elderly is currently not available. Therefore, we aimed to develop a nomogram for predicting the probability of negative prognosis in aged patients with acute ischemic stroke undergoing thrombectomy. In addition, we sought to investigate the association between histological thrombus composition and stroke characteristics. To this end, we prospectively studied a developed cohort using data collected from a stroke center from November 2015 to December 2019. The main outcome was functional independence, defined as a modified Rankin Scale score ≤ 2 at 90 days following a mechanical thrombectomy. A nomogram model based on multivariate logistic models was generated. The retrieved thrombi were stained with hematoxylin and eosin and assessed according to histological composition. Our results demonstrated that age ≥ 72 years was independently associated with poor outcome. A total of 304 participants completed the follow-up data to generate the nomogram model. After multivariate logistic regression, five variables remained independent predictors of outcome, including older age, hemorrhagic transformation, thrombolysis in cerebral infarction score, National Institute of Health Stroke score, and neutrophil-to-lymphocyte ratio, and were used to generate the nomogram. The area under the receiver-operating characteristic curve of the model was 0.803. The clots from elderly subjects with large-artery atherosclerosis, anterior circulation, and successful recanalization groups had a higher percentage of fibrin compared to those of younger patients. This is the first nomogram to be developed and validated in a stroke center cohort for individualized prediction of poor outcome in elderly patients after mechanical thrombectomy. Clot composition provides valuable information on the underlying pathogenesis of oxidation in older patients.

Endovascular Treatment for Vertebrobasilar Artery Tandem Occlusion Beyond 24 Hours From Onset of Stroke-Case Report

We report a case in which endovascular treatment (EVT) was performed for vertebral and basilar artery (VA and BA) tandem occlusion beyond 24 hours from onset of stroke. A 78-year-old man was admitted to our institution with dysarthria and disturbance of gait. MRI revealed occlusion of the BA with acute ischemic change in bilateral cerebellum and brain stem. At 36 hours after onset and 30 hours after administration, EVT was performed because of deteriorating neurological symptom. Successful revascularization was achieved with percutaneous transluminal angioplasty for VA and thrombectomy for BA occlusion. The neurological symptoms were improved in postoperative course.

Posterior circulation tandem occlusions: Classification and techniques

BACKGROUND

Posterior circulation tandem occlusions are poorly characterized in current literature. Data regarding endovascular approaches and outcomes in this patient subgroup is extremely limited.

METHODS

We conducted a retrospective analysis of a prospectively maintained database and identified 17 patients with posterior circulation tandem occlusions who underwent mechanical thrombectomy between 2014 and 2019.

RESULTS

Of 17 patients with posterior circulation tandem occlusion, the mean age was 55.76 ± 11.8 with 35.3% female. The mean NIHSS score on presentation was 17.2 ± 9.2. Tissue plasminogen activator was administered in 7 (41.2%) patients, stent-retrievers alone were used in 2 (11.8%), aspiration catheters alone were used in 2 (11.8%), a combination was used 12 (70.6%), and a self-expandable stent in 5 (29.4%). The mean number of device passes was 2.24 ± 2.02, recanalization failure occurred in 4 (23.5%) patients, the mean time from stroke onset to puncture was 6.9 ± 2.4 h, and the mean time from puncture to recanalization was 59.3 ± 26.6 min. Postprocedural symptomatic ICH occurred in 1 (5.9 %) patient, periprocedural ICH/SAH occurred in 2 (11.8%), periprocedural distal emboli occurred in 0 (0%), periprocedural vessel dissection occurred in 1 (5.9%), and periprocedural vessel perforation occurred in 1 (5.9%) patient. TICI score>2b was achieved in 13 (76.5%) patients. An improvement in NIHSS>3 at discharge occurred in 10 (58.8%) patients, and good outcomes (mRS score < 2) occurred in 7 (41.2%). The mean length of stay was 11.6 ± 12.2 days, and the mortality rate was 41.2%.

CONCLUSION

Endovascular intervention with mechanical thrombectomy is safe and feasible in patients with posterior circulation tandem occlusions.

Mechanical Thrombectomy for Tandem Vertebrobasilar Stroke: Characteristics and Treatment Outcome

Background and Purpose- Tandem vertebrobasilar strokes are not well-known causes of posterior circulation stroke. The purpose of this study was to investigate the characteristics and outcome of mechanical thrombectomy in patients with tandem vertebrobasilar stroke. Methods- Acute basilar artery occlusion patients with tandem vertebral artery (VA) stenosis/occlusion who underwent mechanical thrombectomy were retrospectively analyzed. Concomitant tandem VA steno-occlusion was defined as severe stenosis/occlusion of the extracranial VA with impaired flow. Clinical/angiographic characteristics, recanalization rate, procedure time, and clinical outcome were evaluated with comparisons according to the treatment strategy. Results- Tandem vertebrobasilar occlusion was identified in 24.6% (55 of 224) of the acute basilar artery occlusion patients. Overall successful recanalization and good clinical outcome was achieved in 87.2% (48 of 55) and 30.9% (17 of 55) of the patients. There were no significant differences in procedure time, recanalization rate, and clinical outcome in comparisons of the VA access route selection or angioplasty of the tandem VA lesion. Two patients developed short-term recurrent basilar artery occlusion when angioplasty of the tandem VA lesion was not performed. Good clinical outcome was more likely with lower baseline National Institutes of Health Stroke Scale score (odds ratio, 0.87 [95% CI, 0.787-0.961]; P=0.006) and short onset-to-recanalization time (odds ratio, 0.993 [95% CI, 0.987-0.999]; P=0.03). Conclusions- Tandem vertebrobasilar occlusion may be a frequent pathological mechanism of posterior circulation stroke. Good outcome may be achieved by strategic choice of the access route and selective angioplasty of the tandem VA lesion.

Treatment Strategies for Basilar Top Syndrome Caused by Acute Vertebral Artery Occlusion

Objective

We report a patient with basilar artery embolism caused by vertebral artery stenosis who was successfully treated using simultaneous percutaneous transluminal angioplasty (PTA) and mechanical thrombectomy.

Case Presentation

A 64-year-old male, who had undergone medical treatment for cerebellum infarction at another hospital, was referred to our hospital due to disturbance of consciousness. Angiography revealed acute occlusion of the first part of the right vertebral artery and an embolism of the top of basilar artery. After performing PTA to create an approach route for the embolism, we collected it using a clot recovering device. The postoperative course was good, and the patient was discharged with mild ataxia and dysarthria.

Conclusion

We report the successful treatment of progressive cerebral infarction of the posterior circulation with revascularization 30 hours after symptom onset. Unlike the anterior circulation, the posterior circulation consists of smaller arteries and fewer collateral arteries, making it vulnerable to ischemic attack. Therefore, shortening the time until treatment may improve the outcome.

Endovascular treatment of patients with high-risk symptomatic intracranial vertebrobasilar stenoses: long - term outcomes

Background and purpose

We present the long-term outcome after endovascular treatment of symptomatic intracranial posterior circulation stenoses.

Methods

30 patients with symptomatic intracranial posterior circulation stenoses exceeding 70% underwent endovascular treatment between 2006 and 2012. Data regarding presentation, follow-up, procedure details, complications and imaging follow-up were reviewed. All surviving patients underwent a phone interview to establish their current Modified Ranking Scales (MRS).

Results

Stenoses of the intracranial vertebral artery (24 patients) and basilar artery (6 patients) were treated with stents (10 patients), angioplasty alone (13 patients) or both (5 patients). Two procedures failed. One patient (3.3%) died after the procedure, two had stroke (6.6%) and one a subarachnoid haemorrhage without ensuing deficit. Two patients (6.7%) had asymptomatic complications (dissection and pseudoaneurysm). The median clinical follow-up time was 7 years. Of the 29 patients who survived the procedure, 6 died due to unrelated causes. Three patients (10%) had recurrent strokes and two (6.7%) a transient ischaemic attack in the posterior circulation. Two patients had subsequent middle cerebral artery strokes. Five (16.7%) patients had recurrent stenoses and three (10%) occlusions of the treated artery. Retreatment was performed in six patients, three (10%) with PTA and three (10%) with stenting. Current MRS scores were as follows: nine MRS 0, eight MRS 1, four MRS 2 and one MRS 4.

Conclusions

Long-term follow-up after endovascular treatment of high-risk symptomatic intracranial posterior circulation stenoses shows few stroke recurrences. Treatment of intracranial vertebral artery stenosis may be beneficial in appropriately selected patients.

Endovascular treatment of tandem occlusions in vertebrobasilar stroke: technical aspects and outcome compared with isolated basilar artery occlusion

Background and purpose

Acute basilar artery occlusion (BAO) is a devastating disease with a high rate of mortality and morbidity, and early recanalization is crucial to achieve a good prognosis. The best treatment strategy for BAO combined with a proximal stenosis (tandem occlusion) is not yet clear. Our study aimed to evaluate whether and how vertebrobasilar tandem occlusions can be treated effectively and safely compared with isolated BAO.

Materials and methods

Fifty-two patients with acute vertebrobasilar occlusive stroke treated with mechanical thrombectomy were identified in a prospective database from March 2010 to September 2016. We retrospectively analysed the clinical, technical, and functional outcomes of the patients.

Results

Of the 52 patients, 15 presented with a tandem occlusion, 14 with a single intracranial occlusion due to an underlying stenosis, and 23 with a single embolic BAO. Successful recanalization was achieved in all of the patients with tandem occlusions (modified Thrombolysis in Cranial Infarction 2b/3) and in 35 of 37 patients with a single BAO (with and without stenosis). A favourable outcome was achieved (modified Rankin Scale ≤2) in 8 of the 15 patients with a tandem occlusion compared with 4 of the 14 patients with a single BAO with underlying stenosis and 5 of the 23 patients with isolated embolic BAO (p=0.18).

Conclusions

We suggest that endovascular treatment of vertebrobasilar tandem occlusions is safe and feasible, with a high rate of good outcome.

Mechanical Thrombectomy in Subtypes of Basilar Artery Occlusion: Relationship to Recanalization Rate and Clinical Outcome

Background Acute stroke because of basilar artery occlusion (BAO) represents 1% of all ischemic strokes. However, recanalization rates and treatment outcome for the different pathologic subtypes of BAO stroke are not fully understood. Purpose To compare the recanalization rate and clinical outcomes of mechanical thrombectomy in different subtypes of BAO. Materials and Methods Eighty-two patients (46 men and 36 women; mean age, 73 years; age range, 20-90 years; mean age in men, 70 years [age range, 20-90 years]; mean age in women, 75 years [age range; 61-90 years]) with acute BAO who underwent mechanical thrombectomy between March 2010 and December 2017 were retrospectively analyzed. Patients were classified into three groups: embolism without vertebral artery (VA) steno-occlusion (group 1), embolism from tandem VA steno-occlusion (group 2), and in situ atherosclerotic thrombosis (group 3). Clinical and angiographic characteristics, recanalization rate, procedure times, and clinical outcomes were compared between groups by using the Kruskal-Wallis, Pearson χ², and Fisher exact tests. Results The incidence of BAO according to stroke mechanism were as follows: group 1, n = 34 (41%); group 2, n = 28 (34%), group 3, n = 20 (24%). Overall, successful recanalization (modified Thrombolysis in Cerebral Infarction grade 2b or 3) was achieved in 78% (64 of 82) and favorable outcome (90-day modified Rankin Scale score, 0-2) in 37% (30 of 82) of the patients. The procedure time was shorter in group 1 than in group 2 (49 vs 66 minutes, respectively; P = .01). Group 1 showed a higher successful recanalization rate than group 3 (29 of 34 [85%] vs 11 of 20 [55%], respectively; P = .01). Good clinical outcome rate was higher in group 1 than in group 3 (18 of 34 [53%] vs four of 20 [20%], respectively; P = .02). Conclusion The outcome of mechanical thrombectomy for basilar artery occlusion differs according to the pathologic mechanism of stroke; the best outcomes and recanalization rate occurred in patients with embolism without vertebral artery steno-occlusion. © RSNA, 2019 See also the editorial by Hetts in this issue.

Endovascular vs. medical therapy in symptomatic vertebral artery stenosis: a meta-analysis

This meta-analysis aims to compare percutaneous transluminal angioplasty (PTA) to medical treatment (MT) for symptomatic vertebral artery stenosis (SVAS) treatment. We searched PubMed, Springer, Google Scholar, Clinical Trials, Cochrane Central, Chinese National Knowledge Infrastructure, and China Biological Medicine databases. All relevant comparative trials were included. All summary estimates were calculated by random-effect models. Ten comparative trials involving 672 patients were identified. Within 30-day follow-up, there was no significant difference between PTA plus MT and MT alone in vascular death, any stroke, posterior circulation TIA, posterior circulation infarction, and ischemic stroke (all P > 0.05). With a follow-up of more than 1 year, no significant difference was found between PTA plus MT and MT alone in all-cause death (3 vs. 7 %, P = 0.24), vascular death (4 vs. 7 %, P = 0.34), posterior circulation stroke (5 vs. 8 %, P = 0.48), posterior circulation ischemic events (8 vs. 25 %, P = 0.23), posterior circulation TIA (10 vs. 38 %, P = 0.11), posterior circulation infarction (6 vs. 12 %, P = 0.51), vertebral artery occlusion (6 vs. 12 %, P = 0.58), and in secondary long-term events, including any stroke, anterior circulation stroke, hemorrhagic stroke, and myocardial infarction (all P > 0.05), although PTA plus MT could largely reduce the vertebral artery stenosis rate [MD 63.05 %, 95 % CI (32.77-93.34 %), P < 0.01]. Hence, PTA plus MT may be not superior to MT alone for SVAS treatment. Larger randomized trials are needed to verify the optimum therapy for SVAS.