Outcomes of endovascular treatment of basilar artery occlusion in the stent retriever era: a systematic review and meta-analysis

Stent Retriever Thrombectomy Potentially Increases the Recanalization Rate, Improves Clinical Outcome, and Decreases Mortality in Acute Basilar Occlusion: A Systematic Review and Meta-Analysis

BACKGROUND

Acute basilar artery occlusion (BAO) is a devastating condition if untreated. The optimal treatment strategy, however, is unknown. Historically, interventional approaches have been favored over intravenous thrombolysis (IVT), although this is not supported by good evidence. The aim of this systematic review and meta-analysis was to summarize and compare the results for treatment modalities of BAO, namely, IVT and interventional stent retriever thrombectomy (SRT).

METHODS

Studies on IVT and SRT in BAO were systematically searched. Successful recanalization (TICI ≥2b), favorable clinical outcome (modified Rankin Scale score ≤2), mortality, and the rate of symptomatic intracranial hemorrhage (SICH) were the target parameters. Only studies with ≥15 patients were included. IVT prior to SRT was allowed. Studies were excluded (1) if >1 thrombectomy device was used in >50% of the patients and (2) when data on outcome or treatment could not be parsed (e.g. registries). Odds ratios (ORs) were calculated using Mantel-Haenszel risk ratio estimation. Results are given as OR and the 95% confidence interval (95% CI). The χ2 test was used to compare the outcome parameters clinical outcome, recanalization, mortality, and SICH.

RESULTS

A total of 17 studies (4 on IVT and 13 on SRT) with a total of 672 patients (IVT, n = 314; SRT, n = 358) were identified. Cumulatively, we found a highly significantly improved clinical outcome (43 vs. 31%, p = 0.004, OR [95% CI] = 1.66 [1.21, 2.76]), increased recanalization rate (88 vs. 60%, p < 0.00001, OR [95% CI] = 3.99 [2.73, 5.84]), and decreased mortality (26 vs. 41%, p = 0.0004, OR [95% CI] = 1.86 [1.33, 2.61]), as well as an equal rate of SICH (5 vs. 7%, p = 0.15, OR [95% CI] = 1.68 [0.82, 3.43]), in patients treated with SRT compared to those treated with IVT alone.

CONCLUSIONS

The data from this meta-analysis suggest a possible superiority of SRT over IVT, pending positive results of randomized controlled trials. According to international recommendations, patients with BAO should preferentially be treated with SRT; if no contraindications exist, IVT should not be withheld.

Prediction of intracranial hemorrhages after mechanical thrombectomy of basilar artery occlusion

Background

Mechanical thrombectomy (MT) achieves high recanalization rates in basilar artery occlusion (BAO). A severe complication of MT in BAO is intracranial hemorrhage (ICH). Yet, knowledge of risk factors for ICH after MT in BAO is limited.

Objective

To evaluate clinical and procedural parameters of patients treated with MT owing to BAO to identify potential risk factors for ICH—in particular, symptomatic ICH (sICH), and assess their clinical relevance.

Methods

We conducted a retrospective analysis of 101 consecutive patients presenting with BAO, who were treated with MT in our centre. Important clinical and procedural parameters were analysed as possible predictors for any ICH and sICH according to the Heidelberg Bleeding Classification using univariate tests and multivariate logistic regressions.

Results

ICH occurred in 25 (24.8%) patients, with a total of 7 (6.9%) developing sICH. Treatment with glycoprotein IIb/IIIa (GPIIb/IIIa) inhibitors was independently associated with any ICH (OR=24.67, 95% CI 4.90 to 124.03) and sICH (OR=7.08, 95% CI 1.36 to 36.78). Also, a longer onset-to-recanalization time increased the risk of both any ICH (OR=1.17, 95% CI 1.07 to 1.31) and sICH (OR=1.22, 95% CI 1.08 to 1.42). Higher serum glucose levels were associated with a higher incidence of any ICH (OR=1.39, 95% CI 1.06 to 1.85) and a higher risk of a fatal outcome (OR=1.03, 95% CI 1.01 to 1.05).

Conclusion

Administration of GPIIb/IIIa inhibitor during the course of MT of BAO was identified as an important risk factor in the development of any ICH and sICH.

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.

Vertebral Artery Patency and Thrombectomy in Basilar Artery Occlusions

Background and Purpose—

Factors influencing recanalization success in basilar artery occlusions are largely unknown. Preliminary evidence has suggested that flow arrest in the vertebral artery contralateral to the catheter bearing vertebral artery may facilitate recanalization. The aim of this analysis was to assess the impact of anatomic variations and flow conditions on recanalization success in basilar artery occlusion treated with mechanical thrombectomy.

Methods—

Consecutive basilar artery occlusions treated with second-generation thrombectomy devices at a single-center were retrospectively analyzed. Baseline patients’ characteristics, occlusion length, collateral circulation, underlying stenosis, incomplete occlusions, and patency of the vertebral arteries were analyzed with regards to recanalization success. Aplastic or hypoplastic vertebral artery contralateral to the catheter position was defined as contralateral low flow condition. Logistic regression analysis was used to examine the association between anatomic variations and flow conditions in relation to complete recanalization and the modified Rankin Scale score while controlling for several potentially confounding variables. Clinical impact was evaluated using the modified Rankin Scale score of ≤3.

Results—

One hundred fifteen patients were included (mean age 71.5±12.8, m:f=2:1, median National Institutes of Health Stroke Scale =15, interquartile range =10–22). Complete recanalization was more often observed in patients with contralateral low flow conditions (80.6% versus 50.0%), which remained an independent predictor of complete recanalization in multivariable analysis (adjusted odds ratio, 5.81; 95% CI, 1.97–17.19). Patients with complete posterior recanalization had lower in-hospital mortality (16.4% versus 41.7%) and more often achieved modified Rankin Scale score of ≤3 (49.4% versus 8.3%), even after adjusting for potential confounders (adjusted odds ratio, 15.93; 95% CI, 1.42–179.00).

Conclusions—

Contralateral low flow condition (vertebral artery aplasia or hypoplasia) seems to be an independent factor for fewer distal emboli and complete recanalization in basilar artery occlusion patients treated by modern endovascular devices. Complete recanalization reflecting the absence of peri-interventional clot fragmentation brings clear clinical benefit. Further studies are warranted to evaluate the need for contralateral flow modulation or ipsilateral balloon guide catheter during posterior circulation thrombectomy in patients with bilaterally patent vertebral arteries.

Firstline a direct aspiration first pass technique versus firstline stent retriever for acute basilar artery occlusion: a systematic review and meta-analysis

INTRODUCTION

Acute basilar artery occlusion (BAO) can result in extremely high disability and mortality. Stent retrievers (SRs) can achieve a high recanalization rate for BAO, therefore improving favorable outcomes. However, the efficacy of a direct aspiration first pass technique (ADAPT) to treat BAO is unclear. Our aim was to compare the efficacy and safety of firstline ADAPT with that of firstline SR for patients with acute BAO.

METHODS

Three databases were systematically searched for literature reporting outcomes on thrombectomy for acute BAO with both firstline ADAPT and firstline SR. The modified Newcastle-Ottawa scale was applied to assess bias risk. The random effects model was used.

RESULTS

Of 50 articles, 5 cohort studies (2 prospective and 3 retrospective) were included in our research. 193 cases were treated with firstline ADAPT and 283 cases received firstline SR. Successful recanalization rate was significantly higher in the firstline ADAPT group (OR=2.0, 95% CI 1.1 to 3.5). Procedure time (mean difference=-27.6 min, 95% CI -51.0 to -4.3) and the incidence of new territory embolic event (OR=0.2, 95% CI 0.05 to 0.83) was significantly less in the firstline ADAPT group. No significant difference was observed between the firstline ADAPT and firstline SR groups for rate of complete recanalization, rescue therapy, any hemorrhagic complication, favorable outcomes, or mortality at 90 days.

CONCLUSIONS

Our meta-analysis suggested that for patients with acute BAO, firstline ADAPT might achieve higher and faster recanalization, comparable neurological improvement and safety compared with firstline SR. Further studies are needed to confirm these results.

Differences in characteristics and outcomes after endovascular therapy: A single-center analysis of patients with vertebrobasilar occlusion due to underlying intracranial atherosclerosis disease and embolism

BACKGROUND

Therapeutic strategies and outcomes vary with stroke subtypes for patients with acute vertebrobasilar occlusion (VBAO). This study aimed to compare characteristics and outcomes of VBAO due to intracranial atherosclerotic disease (ICAD) and embolisms and identify baseline predictors of ICAD.

METHODS

Patients with VBAO who received endovascular therapy (EVT) were retrospectively analyzed. Participants fulfilling the criteria were classified as the ICAD group (focal stenosis of >70%, or fixed stenosis >50% in addition to either flow and perfusion impairment on angiography or an evident reocclusion tendency) and the embolism group (defined as no evidence of focal significant stenosis after thrombolysis or thrombectomy). Baseline characteristics and outcomes after EVT were compared between the two groups, and logistic regression was performed to explore the factors associated with ICAD.

RESULTS

Among the 133 patients enrolled, 95 (71.4%) patients were categorized in the ICAD group, and 38 (28.6%) in the embolism group. A history of atrial fibrillation (odds ratio (OR) 0.142; 95% confidence interval (CI) (0.028-0.707), p = 0.017), distal basilar artery occlusion (OR 0.107; 95% CI (0.040-0.289), p < 0.001) and V4 segment occlusion (OR 3.423; 95% CI (1.172-9.999), p = 0.024) were independently associated with ICAD. Patients with VBAO due to ICAD had a lower rate of recanalization (81.1% vs 100%, p = 0.004), but the 90-day good clinical outcome was comparable (41.1% vs 50.0%, p = 0.347).

CONCLUSIONS

The occlusion sites and a history of atrial fibrillation might be helpful in predicting ICAD in patients with VBAO. Patients with ICAD who were treated by EVT had a lower rate of recanalization but comparable 90-day good outcomes.

Acute Basilar Artery Occlusion: Does Recanalization Improve Clinical Outcome? A Critically Appraised Topic

BACKGROUND

Acute basilar artery occlusion (BAO) is a devastating, life-threatening condition that accounts for approximately 1% of all strokes. Currently, there is no consensus on the best treatment strategy for patients with BAO. Whereas endovascular reperfusion therapy is proven to improve outcomes in anterior circulation stroke, its benefit in acute BAO has not been confirmed in randomized controlled trials.

OBJECTIVE

To critically assess the current evidence regarding recanalization in acute BAO, and to discuss the outcomes of different treatment strategies in the management of acute BAO.

MATERIALS AND METHODS

The objective was addressed through the development of a critically appraised topic that included a clinical scenario, structured question, literature search strategy, critical appraisal, assessment of results, evidence summary, commentary, and bottom-line conclusions. Participants included consultant and resident neurologists, and content experts in the field of vascular and hospital neurology.

RESULTS

A recent meta-analysis was selected for critical appraisal to assess the recanalization hypothesis in acute BAO. The authors performed a systematic literature search through August 2013 and pooled in the analysis of 45 studies and 2056 patients. The overall recanalization rate was 75% in this meta-analysis. The authors concluded that recanalization was associated with a 1.5-fold reduction in the risk of death or dependency, and a 2-fold reduction in the risk of mortality. Subgroup analysis comparing different modes of intervention revealed data that favor endovascular intervention over intravenous thrombolysis (IVT). However, the authors were not able to obtain a statistically valid direct comparison of the 2 therapies as their meta-analysis included observational studies. Subgroup analysis on the treatment window revealed that onset-to-treatment time of <12 hours was associated with a higher recanalization rate (81%) and a lower intracranial hemorrhage rate (10%) compared with onset-to-treatment time >12 hours.

CONCLUSIONS

IVT is the standard of care for BAO patients presenting within 4.5 hours of symptom onset, whereas recanalization is associated with better outcomes regardless of how recanalization is achieved. Randomized controlled trials comparing IVT plus endovascular treatment versus IVT in the treatment of acute BAO are needed to provide evidence-based management guidance.

Endovascular Thrombectomy for Acute Basilar Artery Occlusion: A Multicenter Retrospective Observational Study

Background

Despite the recent acceptance of thrombectomy as the standard of care in patients with acute anterior circulation stroke, the benefits of thrombectomy remain uncertain for patients with acute basilar artery occlusion (BAO). This study aimed to evaluate the effectiveness and safety of thrombectomy and to identify predictors of outcomes in a large cohort of patients with acute BAO.

Methods and Results

This study included 212 consecutive patients with acute BAO who underwent either stent‐retriever or contact aspiration thrombectomy as the first‐line approach between January 2011 and August 2017 at 3 stroke centers. Clinical and radiologic data were prospectively collected and stored in a database at each center. Multivariable ordinal logistic regression was performed to assess the association between each characteristic and 90‐day modified Rankin scale scores. Reperfusion was successful in 91.5% (194/212) of patients; 44.8% (95/212) of patients achieved 90‐day modified Rankin scale 0 to 2. The symptomatic hemorrhage rate was 1.9% (4/212) and mortality was 16% (34/212). In a multivariable ordinal regression, younger age, lower National Institute of Health stroke scale on admission, and absence of diabetes mellitus and parenchymal hematoma were significantly associated with a favorable shift in the overall distribution of 90‐day modified Rankin scale scores. Treatment outcomes were similar between patients who received stent‐retriever thrombectomy and contact aspiration thrombectomy as the first‐line technique.

Conclusions

Endovascular thrombectomy was effective and safe for treating patients with acute BAO. Age, the baseline National Institute of Health stroke scale, diabetes mellitus, and parenchymal hematoma were associated with better outcomes. This study showed no superiority of the stent‐retriever over the aspiration thrombectomy for treating acute BAO.

[Stroke due to acute occlusion of the basilar artery : Diagnosis and treatment]

Acute occlusion of the basilar artery is a rare and, if left untreated, severe neurovascular condition with a high mortality. The clinical presentation is often atypical and hence diagnosis may be delayed. Because of the devastating natural course, recanalization strategies were often more aggressive than in patients with occlusions in the anterior circulation. To date, there is no evidence-based therapy, and recent larger registry studies and meta-analyses do not show a clear superiority of endovascular approaches over systemic thrombolysis alone. The current review aims to provide an overview of the most critical aspects in clinical and radiological diagnosis and treatment of basilar artery thrombosis.

Mechanical Thrombectomy for Acute Basilar Artery Occlusion in Early Therapeutic Time Window

Background: The natural history of basilar artery occlusion (BAO) is devastating, with morbidity rates increasing up to 80%. However, the efficacy of recanalization therapy for BAO has not been established as yet. Objective: We analyzed consecutive cases of BAO treated with mechanical thrombectomy (MT) to evaluate its safety and efficacy and to determine factors associated with the prognosis. Methods: Between October 2011 and September 2016, MT was performed in 34 patients with BAO. MT was performed using the Penumbra system and stent retriever. CT perfusion was used for evaluating patients. Cerebral blood flow (CBF) maps and cerebral blood volume (CBV) maps were evaluated. CBF/CBV mismatch was defined as ≥50% penumbra. Clinical outcomes were correlated with demographic, clinical, and radiographic findings. Results: The median baseline National Institutes of Health Stroke Scale score was 29 (14-33). The recanalization rate (≥thrombolysis in cerebral infarction grades 2b) was 100%. The median onset to recanalization time (OTR) was 197 (160-256) min. Favorable outcomes (modified Rankin Scale ≤2) at 90 days occurred in 56% (n = 19 of 34). The mortality rate at 90 days was 12% (n = 4 of 34). In univariate analysis, intravenous (IV) recombinant tissue-type plasminogen activator (rt-PA) use, and OTR were significantly associated with favorable outcomes. In a multivariate logistic regression model, IV rt-PA use and lower National Institute of Health Stroke Scale score were significantly related to favorable outcomes. Conclusion and Relevance: Multimodal endovascular therapy using the Penumbra system and stent retriever demonstrated a high recanalization rate and favorable outcomes for BAO. Both devices were feasible and effective in the treatment of BAO. An approach combining MT with IV thrombolysis provided a better recanalization rate and more favorable clinical outcomes.