Endovascular thrombectomy for basilar artery occlusion: translating research findings into clinical practice

Endovascular management of acute stroke

Stroke related to large vessel occlusion is a leading cause of disability and death worldwide. Advances in endovascular therapy to reopen occluded arteries have been shown to reduce patient disability and mortality. Expanded indications to treat patients with large vessel occlusion in the late window (>6 h from symptom onset), with basilar artery occlusion, and with large ischaemic core at presentation have enabled treatment of more patients with simplified imaging methods. Ongoing knowledge gaps include an understanding of which patients with large ischaemic infarct are more likely to benefit from endovascular therapy, the role of endovascular therapy in patients who present with low National Institutes of Health Stroke Scale scores or medium or distal vessel occlusion, and optimal management of patients with underlying intracranial atherosclerotic disease. As reperfusion can now be facilitated by intravenous thrombolysis, mechanical thrombectomy, or both, the development of cytoprotective or adjunctive drugs to slow infarct growth, enhance reperfusion, or decrease haemorrhagic risk has gained renewed interest with the hope to improve patient outcomes.

Vertebrobasilar Artery Occlusion Treatment Outcomes Within 24 hours of Estimated Occlusion Time

BACKGROUND AND OBJECTIVES

The aim of this study was to investigate the efficacy and safety of endovascular treatment (EVT) in patients with acute vertebrobasilar artery occlusion (VBAO) within 24 hours of estimated occlusion time (EOT) and to evaluate the effect of early and late time window in a cohort of patients with VBAO treated with EVT.

METHODS

Retrospective analysis was conducted on patients within 24 hours of the EOT in 65 stroke centers in China. Favorable outcome was defined as modified Rankin Scale ≤3 at 90 days. Patients were divided into the medical management (MM) group and the EVT group. Times were dichotomized into early (EOT ≤6 hours) and late (>6 hours) time windows. Multivariate logical regression models were used to evaluate the efficacy and safety of EVT and the effect of time windows on outcomes in EVT patients.

RESULTS

Among 4124 patients, 2473 and 1651 patients were included in the early and late windows, respectively. 1702 patients received MM and 2422 were treated with EVT. EVT was associated with a higher rate of a favorable outcome at 90 days both in early (odds ratio [OR] 2.16, 95% CI 1.94-2.41) and late (OR 1.89, 95% CI 1.65-2.17) time windows. No differences were found regarding favorable outcome (OR 0.95, 95% CI 0.87-1.03) between VBAO patients treated with EVT within and beyond 6 hours.

CONCLUSION

Patients with acute VBAO who received EVT within 24 hours were associated with improved favorable outcome compared with patients who received MM. EVT beyond 6 hours is feasible and safe with no increase in symptomatic intracranial hemorrhage.

Impact of prodromal symptoms on the prognosis of patients with basilar artery occlusion treated with mechanical thrombectomy

INTRODUCTION

Even with reperfusion therapies, the prognosis of patients with basilar artery occlusion (BAO) related stroke remains poor. We aimed to test the hypothesis that the presence of prodromal symptoms, an easily available anamnestic data, is a key determinant of poor functional outcome.

PATIENTS AND METHODS

Data from patients with BAO treated in Lille, France, with mechanical thrombectomy (MT) between 2015 and 2021 were prospectively collected. The presence of prodromal symptoms was defined by previous transient neurological deficit or gradual progressive clinical worsening preceding a secondary sudden clinical worsening. We compared the characteristics of patients with and without prodromal symptoms. We built multivariate logistic regression models to study the association between the presence of prodromal symptoms and functional (mRS 0-3 and mortality), and procedural (successful recanalization and early reocclusion) outcomes.

RESULTS

Among the 180 patients, 63 (35%) had prodromal symptoms, most frequently a vertigo. Large artery atherosclerosis was the predominant cause of stroke (41.3%). The presence of prodromal symptoms was an independent predictor of worse 90-day functional outcome (mRS 0-3: 25.4% vs 47.0%, odds ratio (OR) 0.39; 95% confidence interval (CI) 0.16-0.86) and 90-day mortality (OR 2.17; 95% CI 1.02-4.65). Despite similar successful recanalization rate, the proportion of early basilar artery reocclusion was higher in patients with prodromal symptoms (23.8% vs 5.6%, p = 0.002).

DISCUSSION AND CONCLUSION

More than one third of BAO patients treated with MT had prodromal symptoms, especially patients with large-artery atherosclerosis. Clinicians should systematically screen for prodromal symptoms given the poor related functional outcome and increased risk of early basilar artery reocclusion.

Bailout intracranial angioplasty or stenting following thrombectomy for acute large vessel occlusion in China (ANGEL-REBOOT): a multicentre, open-label, blinded-endpoint, randomised controlled trial

BACKGROUND

Unsuccessful recanalisation or reocclusion after thrombectomy is associated with poor outcomes in patients with large vessel occlusion (LVO) acute ischaemic stroke (LVO-AIS). Bailout angioplasty or stenting (BAOS) could represent a promising treatment for these patients. We conducted a randomised controlled trial with the aim to investigate the safety and efficacy of BAOS following thrombectomy in patients with LVO.

METHODS

ANGEL-REBOOT was an investigator-initiated, multicentre, prospective, randomised, controlled, open-label, blinded-endpoint clinical trial conducted at 36 tertiary hospitals in 19 provinces in China. Participants with LVO-AIS 24 h after symptom onset were eligible if they had unsuccessful recanalisation (expanded Thrombolysis In Cerebral Infarction score of 0-2a) or risk of reocclusion (residual stenosis >70%) after thrombectomy. Eligible patients were randomly assigned by the minimisation method in a 1:1 ratio to undergo BAOS as the intervention treatment, or to receive standard therapy (continue or terminate the thrombectomy procedure) as a control group, both open-label. In both treatment groups, tirofiban could be recommended for use during and after the procedure. The primary outcome was the change in modified Rankin Scale score at 90 days, assessed in the intention-to-treat population. Safety outcomes were compared between groups. This trial was completed and registered at ClinicalTrials.gov (NCT05122286).

FINDINGS

From Dec 19, 2021, to March 17, 2023, 706 patients were screened, and 348 were enrolled, with 176 assigned to the intervention group and 172 to the control group. No patients withdrew from the trial or were lost to follow-up for the primary outcome. The median age of patients was 63 years (IQR 55-69), 258 patients (74%) were male, and 90 patients (26%) were female; all participants were Chinese. After random allocation, tirofiban was administered either intra-arterially, intravenously, or both in 334 [96%] of 348 participants. No between-group differences were observed in the primary outcome (common odds ratio 0·86 [95% CI 0·59-1·24], p=0·41). Mortality was similar between the two groups (19 [11%] of 176 vs 17 [10%] of 172), but the intervention group showed a higher risk of symptomatic intracranial haemorrhage (eight [5%] of 175 vs one [1%] of 169), parenchymal haemorrhage type 2 (six [3%] of 175 vs none in the control group), and procedure-related arterial dissection (24 [14%] of 176 vs five [3%] of 172).

INTERPRETATION

Among Chinese patients with unsuccessful recanalisation or who are at risk of reocclusion after thrombectomy, BAOS did not improve clinical outcome at 90 days, and incurred more complications compared with standard therapy. The off-label use of tirofiban might have affected our results and their generalisability, but our findings do not support the addition of BAOS for such patients with LVO-AIS.

FUNDING

Beijing Natural Science Foundation, National Natural Science Foundation of China, National Key R&D Program Beijing Municipal Administration of Hospitals Incubating Program, Shanghai HeartCare Medical Technology, HeMo (China) Bioengineering, Sino Medical Sciences Technology.

Focused update to guidelines for endovascular therapy for emergent large vessel occlusion: basilar artery occlusion patients

BACKGROUND

Endovascular therapy (EVT) dramatically improves clinical outcomes for patients with anterior circulation emergent large vessel occlusion (ELVO) strokes. With recent publication of two randomized controlled trials in favor of EVT for basilar artery occlusions, the Society of NeuroInterventional Surgery (SNIS) Standards and Guidelines Committee provides this focused update for the existing SNIS guideline, 'Current endovascular strategies for posterior circulation large vessel occlusion stroke.'

METHODS

A structured literature review and analysis of studies related to posterior circulation large vessel occlusion (basilar or vertebral artery) strokes treated by EVT was performed. Based on the strength and quality of the evidence, recommendations were made by consensus of the writing committee, with additional input from the full SNIS Standards and Guidelines Committee and the SNIS Board of Directors.

RESULTS

Based on the results of the most recent randomized, controlled trials on EVT for basilar or vertebral artery occlusion, the expert panel agreed on the following recommendations. For patients presenting with an acute ischemic stroke due to an acute basilar or vertebral artery occlusion confirmed on CT angiography, National Institutes of Health Stroke Scale (NIHSS) score of ≥6, posterior circulation Alberta Stroke Program Early CT Score (PC-ASPECTS) ≥6, and age 18-89 years: (1) thrombectomy is indicated within 12 hours since last known well (class I, level B-R); (2) thrombectomy is reasonable within 12-24 hours from the last known well (class IIa, level B-R); (3) thrombectomy may be considered on a case by case basis for patients presenting beyond 24 hours since last known well (class IIb, level C-EO). In addition, thrombectomy may be considered on a case by case basis for patients aged <18 years or >89 years on a case by case basis (class IIb, level C-EO).

CONCLUSIONS

The indications for EVT of ELVO strokes continue to expand and now include patients with basilar artery occlusion. Further prospective, randomized controlled trials are warranted to elucidate the efficacy and safety of EVT in populations not included in this set of recommendations, and to confirm long term outcomes.

Futile recanalization in patients with basilar artery occlusion: assessment of the underlying etiology and the role of perfusion imaging

BACKGROUND

Futile recanalization (FR) after endovascular therapy (EVT) is common in basilar artery occlusion (BAO). The purpose of this study was to investigate the predictors of FR in the posterior circulation with an emphasis on the role of perfusion imaging and its relation to the underlying etiology.

METHODS

We included BAO patients who had pretreatment perfusion imaging and successful recanalization after EVT. Patients were dichotomized into futile and non-futile groups according to the favorable functional outcome at 90 days (modified Rankin Scale (mRS) 0-3). Perfusion abnormalities were assessed using an automated software for Tmax volume measurement and identification of hypoperfusion area based on Tmax>6 s involvement of the pons-midbrain-thalamus (PMT), cerebellum, and temporo-occipital lobe.

RESULTS

Of the 134 enrolled patients, the incidence of FR was 47.8% (64/134). Multivariate logistic analysis showed that a higher National Institutes of Health Stroke Scale (NIHSS) score on admission (adjusted OR (aOR) 1.066; 95% CI 1.011 to 1.125), a longer onset-to-recanalization time (aOR 1.002; 95% CI 1.001 to 1.004), incomplete recanalization (aOR 3.909; 95% CI 1.498 to 10.200), and PMT hypoperfusion (aOR 4.444; 95% CI 1.203 to 16.415) were independent predictors of FR. In patients with embolic occlusion of etiology, PMT hypoperfusion was associated with FR (aOR 8.379; 95% CI 1.377 to 50.994), whereas intracranial atherosclerotic stenosis (ICAS)-related occlusion was not (p=0.587).

CONCLUSIONS

In patients with BAO, the likelihood of FR is associated with PMT hypoperfusion on pretreatment perfusion imaging. In particular, PMT hypoperfusion may be used as an imaging predictor of FR in patients with embolic cause of BAO.

Feasibility and Clinical Outcome Predictors of Mechanical Thrombectomy in Distal Arterial Occlusion Causing Acute Ischemic Stroke: A Monocentric Retrospective Study

BACKGROUND

The feasibility and clinical outcome predictors of mechanical thrombectomy (MT) for strokes caused by distal arterial occlusion (DAO) remain the subject of debate.

METHODS

A retrospective analysis was conducted of patients with consecutive acute ischemic stroke treated using MT. Clinical and procedural-associated factors were studied to compare the efficacy, safety, and short-term and long-term outcomes of MT between the proximal arterial occlusion (PAO) and DAO groups. The predictors of a good functional outcome in the DAO group were also identified.

RESULTS

A total of 116 patients were included in this study, of whom 23 (19.8%) underwent MT for DAO. A higher complete recanalization rate was independently associated with PAO in adjusted models [adjusted odds ratio, 0.596; 95% CI, 0.377-0.941]. The measures of safety and clinical outcome showed no significant differences between the DAO and PAO groups. The National Institute of Health stroke scale (NIHSS) score on admission, hybrid technique use, and complete recanalization rate emerged as independent predictors of a good functional outcome in the DAO group.

CONCLUSIONS

The efficacy, safety, and short-term and long-term outcomes of DAO thrombectomy were similar to those of PAO thrombectomy. The good functional outcome predictors of MT in DAO included NIHSS on admission, hybrid technique use, and complete recanalization. Overall, the findings lead us to propose that MT may be considered a feasible option for treating DAO after a careful risk-benefit analysis.

Predictive value of thrombus enhancement sign for stroke subtype and recanalization in acute basilar-artery occlusion

BACKGROUND

Thrombus enhancement sign (TES) is associated with cardioembolic stroke and first-pass angiographic failure in anterior ischemic stroke. However, the relationship between TES and stroke subtype and recanalization status after endovascular treatment (EVT) in basilar artery occlusion (BAO) remains unknown.

METHODS

This retrospective study included consecutive patients with acute BAO who underwent EVT between January 2020 and September 2023. Each patient underwent baseline non-contrast computed tomography (CT) and CT angiography. Two independent readers assessed the presence of TES. Stroke types were classified according to the Trial of ORG 10172 for Acute Stroke Treatment. Successful recanalization was defined as a modified Thrombolysis in Cerebral Infarction score of 2b-3 after EVT. Clinical and interventional parameters, along with histopathological thrombi examination results, were compared between the TES-positive and TES-negative groups. The associations between TES and stroke subtype and recanalization status were analyzed using univariate and multivariate analyses.

RESULTS

A total of 151 patients were included in the analysis, among whom 116 (77%) exhibited TES. TES showed a significant correlation with cardioembolic and cryptogenic strokes (odds ratio [OR]: 8.56; 95% confidence interval: 3.49-22.4; p < 0.001), whereas the TES-positive thrombi were characterized by a higher fibrin/platelet proportion (p = 0.002) and lower erythrocyte proportion (p = 0.044). The TES-positive group demonstrated favorable outcomes compared to the TES-negative group, including a shorter procedure time (p < 0.001), lower number of thrombectomy attempts (p = 0.010), higher incidence of first pass success (p = 0.022), and lower rate of requiring rescue angioplasty and/or stenting (p < 0.001). In multivariate analysis, TES remained independently associated with successful recanalization (OR: 9.63; 95% CI: 2.33, 47.7; p = 0.003) after adjusting for baseline confounders.

CONCLUSIONS

Visualization of TES serves as a reliable and easily accessible marker for identifying cardioembolic and cryptogenic strokes and predicting recanalization success in thrombectomy for basilar artery occlusion.

Aspiration only versus stent retriever only thrombectomy in basilar artery occlusion: a propensity score-matched analysis of the German Stroke Registry

BACKGROUND

Endovascular treatment has become the standard care for acute basilar artery occlusion (BAO). Uncertainty persists about the optimal thrombectomy technique.

OBJECTIVE

To compare aspiration thrombectomy with stent retriever thrombectomy in patients with BAO in a multicenter real-world patient population.

METHODS

We analyzed data from the German Stroke Registry-Endovascular Treatment (GSR-ET). Patients with isolated BAO who underwent either aspiration or stent retriever thrombectomy were compared, including propensity score matching (PSM). The primary outcome measure was the modified Rankin Scale shift analysis at 90 days. Secondary outcomes included symptomatic intracranial hemorrhage (sICH), procedure complications, and metrics.

RESULTS

Of 13 082 patients in the GSR-ET, 387 patients (mean age 72.0±13.1 years; 45.0% female) fulfilled the inclusion criteria. The thrombectomy technique was aspiration only in 195 (50.4%) and stent retriever only in 192 (49.6%) patients. Functional outcome did not differ between the groups, either before (common OR (cOR) 0.94; 95% CI 0.64 to 1.38) or after PSM (cOR=1.37; 95% CI 0.90 to 2.09). There was no significant difference in sICH (2.6 vs 5.5%; P=0.231; OR=0.46; 95% CI 0.14 to 1.47), but aspiration thrombectomy demonstrated fewer procedure-related complications (4.6% vs 12.5%; P=0.017), a shorter procedure duration (24 vs 48 min; P<0.001), and higher first pass recanalization rates (75.1% vs 44.8%; P<0.001).

CONCLUSIONS

In this study both aspiration and stent retriever thrombectomy showed equal efficacy in terms of functional outcome in patients with BAO. However, procedure complications and metrics might favor aspiration over stent retriever thrombectomy.

Posterior circulation collaterals as predictors of outcome in basilar artery occlusion: a sub-analysis of the BASICS randomized trial

Introduction and purpose

Basilar artery occlusion (BAO) is still one of the most devastating neurological conditions associated with high morbidity and mortality. In the present study, we aimed to assess the role of posterior circulation collaterals as predictors of outcome in the BASICS trial and to compare two grading systems (BATMAN score and PC-CS) in terms of prognostic value.

Methods

We performed a sub-analysis of the BASICS trial. Baseline clinical and imaging variables were analyzed. For the imaging analysis, baseline CT and CTA were analyzed by a central core lab. Only those patients with good or moderate quality of baseline CTA and with confirmed BAO were included. Multivariable binary logistic regression analysis was used to test the independent association of clinical and imaging characteristics with a favorable outcome at 3 months (defined as a modified Rankin Score of ≤3). ROC curve analysis was used to assess and compare accuracy between the two collateral grading systems.

Results

The mean age was 67.0 (±12.5) years, 196 (65.3%) patients were males and the median NIHSS was 21.5 (IQR 11-35). Median NCCT pc-ASPECTS was 10 (IQR10-10) and median collateral scores for BATMAN and PC-CS were 8 (IQR 7-9) and 7 (IQR 6-8) respectively. Collateral scores were associated with favorable outcome at 3 months for both BATMAN and PC-CS but only with a modest accuracy on ROC curve analysis (AUC 0.62, 95% CI [0.55-0.69] and 0.67, 95% CI [0.60-0.74] respectively). Age (OR 0.97, 95% CI [0.95-1.00]), NIHSS (OR 0.91, 95% CI [0.89-0.94]) and collateral score (PC-CS - OR 1.2495% CI [1.02-1.51]) were independently associated with clinical outcome.

Conclusion

The two collateral grading systems presented modest prognostic accuracy. Only the PC-CS was independently associated with a favorable outcome at 3 months.

Temporal progression of functional independence after mechanical thrombectomy in acute vertebrobasilar artery occlusions

BACKGROUND

Neurological recovery after endovascular treatment (EVT) for large vessel occlusion stroke often has diverse timelines. Understanding the temporal progression of functional independence after EVT, especially delayed functional independence (DFI) and highly delayed functional independence (HDFI), in patients who do not improve early is essential for prognostication and rehabilitation. We aimed to analyze the prevalence and predictors of DFI and HDFI after EVT in acute vertebrobasilar artery occlusions (VBAO).

METHODS

Patients with VBAO who received EVT in China were retrospectively enrolled. Early functional independence (EFI) was defined as a modified Rankin Scale (mRS) score of 0-2 at discharge. The incidence and predictors of DFI (mRS score 0-2 at 90 days in non-EFI patients) and HDFI (mRS score 0-2 at 1 year in non-DFI patients) were analyzed.

RESULTS

2422 patients met the study criteria. EFI was observed in 20% (483) of patients. Among non-EFI patients, DFI was observed in 21% (395/1880). HDFI was observed in 13% (191/1439) of non-DFI patients. Younger age (P=0.006), lower pre-EVT National Institutes of Health Stroke Scale (NIHSS) score (P<0.001), higher posterior circulation-Alberta Stroke Program Early CT Score (PC-ASPECTS) (P=0.012), and absence of symptomatic intracranial hemorrhage (sICH) (P<0.001) were predictors of DFI. Predictors of HDFI were younger age (P<0.001) and lower pre-EVT NIHSS score (P<0.001).

CONCLUSION

A considerable proportion of patients have DFI and HDFI. The independent predictors of DFI were younger age, lower pre-EVT NIHSS score, higher PC-ASPECTS, and absence of sICH. Predictors of HDFI included younger age and lower pre-EVT NIHSS score.

Endovascular Therapy for Acute Stroke: New Evidence and Indications

Endovascular therapy (EVT) has revolutionized the treatment of acute ischemic stroke. In the past few years, endovascular treatment indications have expanded to include patients being treated in the extended window, with large ischemic core infarction, basilar artery occlusion (BAO) thrombectomy, as demonstrated by several randomized clinical trials. Intravenous thrombolysis (IVT) bridging to mechanical thrombectomy has also been studied via several randomized clinical trials, with the overall results indicating that IVT should not be skipped in patients who are candidates for both IVT and EVT. Simplification of neuroimaging protocols in the extended window to permit non-contrast CT, CTA collaterals have also expanded access to mechanical thrombectomy, particularly in regions across the world where access to advanced imaging may not be available. Ongoing study of areas to develop include rescue stenting in patients with failed thrombectomy, medium vessel occlusion thrombectomy, and carotid tandem occlusions. In this narrative review, we summarize recent trials and key data in the treatment of patients with large ischemic core infarct, simplification of neuroimaging protocols for the treatment of patients presenting in the late window, bridging thrombolysis, and BAO EVT evidence. We also summarize areas of ongoing study including medium and distal vessel occlusion.

What Is the Evidence for Endovascular Thrombectomy in Posterior Circulation Stroke?

Posterior circulation infarcts comprise approximately 25% of ischemic strokes but are less often treated with recanalization therapy and have longer treatment delays compared with anterior circulation strokes. Among posterior circulation strokes, basilar artery occlusion is associated with the most severe deficits and the worst prognosis. Endovascular thrombectomy is a standard of care for patients with anterior circulation large vessel occlusion, but not until recently were the first randomized controlled trials on endovascular thrombectomy in basilar artery occlusion published. Two of the trials were neutral, whereas two others showed better functional outcome after thrombectomy up to 24 hours of symptom onset compared with best medical treatment, which in most cases had low rates of intravenous thrombolysis. According to observational data, thrombectomy seems to be safe also in isolated posterior cerebral artery occlusions and might be an option for selected patients, even if its outcome benefit is yet to be demonstrated.

History of Neurointervention

In this review article, we aim to provide a summary of the discoveries and developments that were instrumental in the evolution of the Neurointerventional field. We begin with developments in the advent of Diagnostic Cerebral Angiography and progress to cerebral aneurysm treatment, embolization in AVMs and ischemic stroke treatment. In the process we discuss many persons who were key in the development and maturation of the field. A pivotal aspect to rapid growth in the field has been the multidisciplinary involvement of the different neuroscience specialties and therefore we close out our discussion with excitement about ongoing and future developments in the field with a focus on treatments in the non-cerebrovascular disease realm.