Patient selection for mechanical thrombectomy in posterior circulation emergent large-vessel occlusion

Predictors of outcome and symptomatic intracranial hemorrhage in acute basilar artery occlusions: Analysis of the PC-SEARCH thrombectomy registry

INTRODUCTION

Recent randomized controlled trials demonstrated superiority of mechanical thrombectomy compared to medical therapy in acute basilar artery occlusions, however, little data is available to guide clinicians in functional prognosis and risk stratification.

PATIENTS AND METHODS

Data from the retrospectively established PC-SEARCH Thrombectomy registry, which included patients with basilar artery occlusion from eight sites from January 2015 to December 2021, was interrogated. Outcomes were dichotomized into 90-day favorable (mRS ⩽ 3) and unfavorable (mRS > 3). Multivariate logistic regression analysis was performed with respect to the outcome groups and were adjusted for potential confounding baseline characteristics.

RESULTS

Four-hundred-forty-four patients were included in this analysis. Mean age was 66 [SD 15], with 56% male, and comprised of 76% Caucasian. Patients presented with an initial median NIHSS of 18 and 199 patients (44.8%) achieved favorable 90-day functional outcomes. Independent predictors of favorable outcomes included younger age, pc-ASPECTS > 8 (OR 2.30 p < 0.001), and TICI ⩾ 2b (OR 7.56 p < 0.001). Unfavorable outcomes were associated with increasing number of passes (OR 1.29 p = 0.004) and sICH (OR 4.19 p = 0.015). IA-tPA was an independent risk factor for sICH (OR 7.15 p = 0.002) without improving favorable functional outcomes.

CONCLUSION AND DISCUSSION

PC-ASPECTS > 8, successful recanalization (TICI ⩾ 2b), first-pass recanalization, and younger age are independent predictors of favorable 90-day functional outcome in thrombectomy treated patients with acute basilar artery occlusion. Conversely, sICH were independent predictors of unfavorable outcomes. IA-tPA and unsuccessful recanalization are independently associated with sICH.

Basilar artery occlusion: A review of clinicoradiologic features, treatment selection, and endovascular techniques

Basilar artery occlusion (BAO) is an infrequent but often fatal subtype of stroke. Predicting outcomes and selecting patients for endovascular therapy (EVT) remains challenging. Advances in neuroimaging and the development of prognostic scoring systems have augmented clinical decision-making over time. Recent randomized trials, BEST (Basilar Artery Occlusion Endovascular Intervention vs. Standard Medical Treatment), BASICS (Basilar Artery International Cooperation Study), BAOCHE (Basilar Artery Occlusion CHinese Endovascular Trial) and ATTENTION (Endovascular Treatment for Acute Basilar Artery Occlusion), compared EVT and medical management for patients with BAO. These trials yielded mixed results. The former two suggested unclear benefit while the latter two supported a benefit of EVT. While all had limitations, most providers agree caution should be exercised when excluding patients from EVT who may stand to benefit. Further studies are therefore needed to determine the effectiveness, safety, selection criteria, and optimal technical approach for EVT among patients with BAO. Hyperacute-phase advanced imaging can offer several benefits to aid decision making. It is reasonable to exclude patients with low National Institutes of Health Stroke Scale (NIHSS), large imaging-proven cores, and evidence of perforator occlusion by branch atheromatous disease. Herein, we review the clinical presentation, imaging work-up, treatments, and clinical outcomes for BAO, while highlighting knowledge gaps in treatment selection and technique.

Rescue Stent Placement for Acute Ischemic Stroke with Large Vessel Occlusion Refractory to Mechanical Thrombectomy: A Multiethnic Middle Eastern/African/Asian Cohort

PURPOSE

To investigate the safety and effectiveness of rescue stent placement in patients who experienced acute stroke in whom mechanical thrombectomy failed.

METHODS

This was a retrospective review of a multiethnic stroke database. After stent placement, an aggressive antiplatelet protocol was followed with glycoprotein IIb/IIIa infusion. The primary outcomes were incidence of intracerebral hemorrhage (ICH), recanalization score, and favorable prognosis (modified Rankin score ≤ 2) at 90 days. A comparison was made between patients from the Middle East and North Africa (MENA) region and those from other regions.

RESULTS

Fifty-five patients were included, with 87% being men. The mean age was 51.3 years (SD ±11.8); 32 patients (58%) were from South Asia, 12 (22%) from MENA, 9 (16%) from Southeast Asia, and 2 (4%) from elsewhere. Successful recanalization (modified Thrombolysis in Cerebral Infarction score = 2b/3) was achieved in 43 patients (78%), and symptomatic ICH occurred in 2 patients (4%). A favorable outcome at 90 days was seen in 26 of the 55 patients (47%). Apart from significantly older age-mean, 62.8 years (SD ±13; median, 69 years) versus 48.1 years (SD ±9.3; median, 49 years)-and coronary artery disease burden-4 (33%) versus 1 (2%) (P < .05), patients from MENA had risk factors, stroke severity, recanalization rates, ICH rates, and 90-day outcomes similar to those from South and Southeast Asia.

CONCLUSION

Rescue stent placement showed good outcomes and a low risk of clinically significant bleeding in a multiethnic cohort of patients from MENA and South and Southeast Asia, similar to that in published literature.

Functional recovery continues beyond 3 months post-basilar artery thrombectomy: A retrospective cohort study

INTRODUCTION

Untreated basilar artery occlusion (BAO) carries 70% mortality. Guidelines recommend thrombectomy with or without thrombolysis.

AIM

We compared Modified Rankin Scores (mRS) at 3 and 12 months post thrombectomy to determine benefit of long-term follow up.

METHODS

Retrospective, single centre analysis of BAO thrombectomies between 2015 and 2019. Inclusion criteria were symptomatic BAO on CT angiography, absent early ischemic changes, premorbid independence and intervention within 24 h. All received stroke ward care. Results were analysed with simple statistics and binary logistic regression as appropriate.

RESULTS

Of 82 patients: most were male (61%, 50/82) with median age 68 years (IQR 17 years) and median NIHSS 14 (IQR 15). Median door-to-puncture time was 42 min (IQR 72 min). Total deaths were 34.1% (28/82) at 3 months, and 37.8% (31/82) at 12 months. Of 51 patients alive at 12 months: 41% (21/51) had improved mRS, 16% (8/51) had worse mRS and 43% (22/51) had unchanged mRS, compared to 3 months. Improvements to mRS were: one point in 57.1% (14/21), two points in 28.9% (6/21) and three points in 4.8% (1/21). Nursing home admission was avoided in 11.8% (6/51) who improved from mRS4. Increased age was associated with decreased likelihood of reaching the primary outcome OR 0.87, 95% CI 0.76-0.99 (p value = 0.03).

CONCLUSION

Over a quarter of patients improved beyond 3 months. Future studies should adopt long-term follow up as primary outcome.

A low score on the National Institutes of Health Stroke Scale with eye movement disorder may indicate a good candidate for acute mechanical thrombectomy for posterior circulation large vessel occlusion: illustrative cases

BACKGROUND

Basilar artery occlusion (BAO) accounts for 1% of all strokes, and its natural prognosis is extremely poor. There is no consensus on the treatment strategy for mild BAO.

OBSERVATIONS

Between August 2015 and May 2021, 429 patients received mechanical thrombectomy (MT) in the authors' hospital. Three patients had a BAO with a National Institutes of Health Stroke Scale (NIHSS) score of ≤6 and showed eye movement disorder as the main symptom. MT immediately improved ocular symptoms in all three cases, and the patients were discharged with a modified Rankin Scale ≤2.

LESSONS

Lesions responsible for the eye movement disorder are distributed from the midbrain to the pontine tegmentum. These lesions are supplied by the arteries of the interpeduncular fossa, which is impaired by BAO. Symptoms due to problems with the arteries of the interpeduncular fossa can be rapidly improved by MT, and it is useful for preventing neurological deterioration in mild cases. BAO with a low NIHSS score in the presence of eye movement disorder as the main symptom may be a good indication for MT.

Endovascular Treatment for Posterior Circulation Stroke: Ways to Maximize Therapeutic Efficacy

The efficacy of endovascular treatment (EVT) in patients with posterior circulation stroke has not been proven. Two recent randomized controlled trials failed to show improved functional outcomes after EVT for posterior circulation stroke (PC-EVT). However, promising results for two additional randomized controlled trials have also been presented at a recent conference. Studies have shown that patients undergoing PC-EVT had a higher rate of futile recanalization than those undergoing EVT for anterior circulation stroke. These findings call for further identification of prognostic factors beyond recanalization. The significance of baseline clinical severity, infarct volume, collaterals, time metrics, core-penumbra mismatch, and methods to accurately measure these parameters are discussed. Furthermore, their interplay on EVT outcomes and the potential to individualize patient selection for PC-EVT are reviewed. We also discuss technical considerations for improving the treatment efficacy of PC-EVT.

Repeated reperfusion treatment in recurrent ischemic stroke: A retrospective single-center case series

Data regarding repeated reperfusion therapy (rRT) in acute ischemic stroke (AIS), including intravenous thrombolysis and endovascular treatment (EVT), are quite poor. To date, there are only few case reports and five larger studies on repeated EVT. We aimed to report our single-center experience and describe different clinical scenarios of recurrent AIS with emergent large vessel occlusion (LVO), for which the decision-making process could be challenging in the emergency setting. We retrospectively reviewed 765 consecutive AIS patients with LVO, who underwent reperfusion procedures at our comprehensive stroke center, from 2014 to 2020, and identified rRT patients. We identified and reviewed the medical records of eight patients (1.05%), who repeated reperfusive treatment for recurrent stroke within 30 days (early arterial reocclusion, EAR) and after 30 days (late arterial reocclusion, LAR). We assigned collected data to three clinical scenarios, each divided into EAR and LAR cases. All patients had recurrent emergent LVO in the same vessel territory previously affected, both in EAR and LAR patients. A good clinical outcome has been achieved in EAR patients (modified Rankin Score ≤ 2). Artery-to-artery embolic mechanism was more common in the EAR group, while LAR was more frequently associated with cardioembolic source. RRT appears to be an effective treatment option for recurrent LVO, and it should not be withheld in carefully selected patients. EVT should be considered, including aspiration-only and stenting procedures in patients with AIS and recurrent LVO after previous reperfusive treatments, even after a very short time.

Posterior Circulation Endovascular Thrombectomy for Large Vessels Occlusion in Patients Presenting with NIHSS Score ≤ 10

Mechanical thrombectomy (MT) is currently the gold standard treatment for ischemic stroke due to large vessel occlusion (LVO). However, the evidence of clinical usefulness of MT in posterior circulation LVO (pc-LVO) is still doubtful compared to the anterior circulation, especially in patients with mild neurological symptoms. The database of 10 high-volume stroke centers in Europe, including a period of three year and a half, was screened for patients with an acute basilar artery occlusion or a single dominant vertebral artery occlusion ("functional" BAO) presenting with a NIHSS ≤10, and with at least 3 months follow-up. A total of 63 patients were included. Multivariate analysis demonstrated that female gender (adjusted OR 0.04; 95% CI 0-0.84; p = 0.04) and combined technique (adj OR 0.001; 95% CI 0-0.81; p = 0.04) were predictors of worse outcome. Higher pc-ASPECTS (adj OR 4.75; 95% CI 1.33-16.94; p = 0.02) and higher Delta NIHSS (adj OR 2.06; 95% CI 1.16-3.65; p = 0.01) were predictors of better outcome. Delta NIHSS was the main predictor of good outcome at 90 days in patients with posterior circulation LVO presenting with NIHSS score ≤ 10.

Time-Based Decision Making for Reperfusion in Acute Ischemic Stroke

Decision making in the extended time windows for acute ischemic stroke can be a complex and time-consuming process. The process of making the clinical decision to treat has been compounded by the availability of different imaging modalities. In the setting of acute ischemic stroke, time is of the essence and chances of a good outcome diminish by each passing minute. Navigating the plethora of advanced imaging modalities means that treatment in some cases can be inefficaciously delayed. Time delays and individually based non-programmed decision making can prove challenging for clinicians. Visual aids can assist such decision making aimed at simplifying the use of advanced imaging. Flow charts are one such visual tool that can expedite treatment in this setting. A systematic review of existing literature around imaging modalities based on site of occlusion and time from onset can be used to aid decision making; a more program-based thought process. The use of an acute reperfusion flow chart helping navigate the myriad of imaging modalities can aid the effective treatment of patients.

A Meta-Analysis of Prognostic Factors in Patients with Posterior Circulation Stroke after Mechanical Thrombectomy

BACKGROUND

Posterior circulation stroke is characterized by poor prognosis because its optimal thrombolysis "time window" is always missed. After mechanical thrombectomy (MT), the recanalization rate of posterior circulation obstruction is significantly increased, but prognosis remains poor. To best manage patients, prognostic factors are needed to inform MT triaging after posterior circulation stroke.

METHODS

A systematic literature search was done for the period through April 2020. Studies included those with posterior circulation stroke cases that underwent MT. The primary outcome measure in this study was the modified Rankin Scale on day 90.

RESULTS

No outcome differences were found in gender, atrial fibrillation, smoking, and coronary artery disease (OR = 1.07, 95% CI: 0.90-1.28; OR = 1.02, 95% CI: 0.82-1.26; OR = 1.26, 95% CI: 0.94-1.68; and OR = 0.84, 95% CI: 0.58-1.22, respectively). Hypertension, diabetes mellitus, and previous stroke correlated with poorer prognosis (OR = 0.61, 95% CI: 0.48-0.77; OR = 0.60, 95% CI: 0.50-0.73; and OR = 0.74, 95% CI: 0.55-0.99, respectively). However, hyperlipidemia correlated with better prognosis (OR = 1.28, 95% CI: 1.04-1.58).

CONCLUSION

Our analysis indicates that hypertension, diabetes mellitus, or previous stroke correlate with poorer outcomes. Intriguingly, hyperlipidemia correlates with better prognosis. These factors may help inform triage decisions when considering MT for posterior circulation stroke patients. However, large, multicenter, randomized controlled trials are needed to validate these observations.

Blood pressure management after mechanical thrombectomy in stroke patients

Endovascular treatment of acute ischemic stroke (AIS) and mechanical thrombectomy (MT) is proven as a safe and effective novel treatment for emergent large vessel occlusion in the anterior cerebral circulation. However, there are still many unanswered questions on peri and post-procedural management including blood pressure (BP) control. The current guidelines recommend maintaining BP <180/105 mmHg in the first 24 h after MT. However, recent studies suggest that maintaining BP levels at lower levels in the first 24 h after successful revascularization have been associated with favorable functional outcome, reduced mortality rate, and hemorrhagic complications. Not only absolute BP but also its variation in the first 24 h after MT have been associated with neurological outcomes. Evidence on the effect of BP variability (BPV) after MT in AIS even though limited, it does indicate the association of the higher BPV in the first 24 h after MT and poor functional outcomes in AIS. In this review, we will discuss the current literature on BP management in the first 24 h after MT and the impact of BPV in the first 24 h after MT.

Endovascular treatment combined with vertebral artery endarterectomy for patients with acute tandem vertebrobasilar artery occlusion

PURPOSE

To evaluate the safety and efficacy of endovascular treatment combined with vertebral artery endarterectomy in patients with acute tandem vertebrobasilar artery occlusion.

METHODS

From April 2017 to March 2019, three patients with acute basilar artery occlusion combined with ostial vertebral occlusion in our institution were enrolled in the study. They underwent endovascular treatment combined with vertebral artery endarterectomy. The clinical, technical and functional outcomes of the patients were retrospectively analysed.

RESULTS

All three patients in the study underwent complete recanalization. The modified Thrombolysis in Cerebral Infarction (mTICI) grade was 2b/3 in all patients. The modified Rankin Scale (mRS) score was 0-2 for the three patients at 3 months. Follow-up CT scans revealed no cerebral haemorrhage, and no patients died during follow-up. All patients achieved good clinical outcomes after the combined treatment.

CONCLUSION

Endovascular treatment combined with vertebral artery endarterectomy is a feasible method to treat patients with acute basilar artery occlusion combined with ostial vertebral occlusion, especially when the guidewire cannot pass through the ostium of the dominant vertebral artery occlusion.

Choice of ANaesthesia for EndoVAScular treatment of acute ischaemic stroke at posterior circulation (CANVAS II): protocol for an exploratory randomised controlled study

INTRODUCTION

Observational and interventional studies indicate that the type of anaesthesia may be associated with the postprocedural neurological function in patients with anterior circulation acute ischaemic stroke undergoing endovascular treatment. Patients with acute posterior circulation ischaemic stroke may experience different physiological changes and result in severe neurological outcome. However, the effect of the type of anaesthesia on postprocedure neurological function remained unclear in this population.

METHODS AND ANALYSIS

This is an exploratory randomised controlled trial that will be carried out at Beijing Tiantan Hospital, Capital Medical University. Patients with acute posterior circulation ischaemic stroke and deemed suitable for emergency endovascular recanalisation will be recruited in this trial. Eighty-four patients will be randomised to receive either general anaesthesia or conscious sedation with 1:1 allocation ratio. The primary endpoint is the 90-day modified Rankin Scale.

ETHICS AND DISSEMINATION

The study has been reviewed by and approved by Ethics Committee of Beijing Tiantan Hospital of Capital Medical University (KY2017-074-02). If the results are positive, the study will indicate whether the type of anaesthesia affects neurological outcome after endovascular treatment of posterior stroke. The findings of the study will be published in peer-reviewed journals and presented at national or international conferences.

TRIAL REGISTRATION NUMBER

NCT03317535.

Epidemiology, Natural History, and Clinical Presentation of Large Vessel Ischemic Stroke

Large vessel occlusions (LVOs), variably defined as blockages of the proximal intracranial anterior and posterior circulation, account for approximately 24% to 46% of acute ischemic strokes. Commonly refractory to intravenous tissue plasminogen activator (tPA), LVOs place large cerebral territories at ischemic risk and cause high rates of morbidity and mortality without further treatment. Over the past few years, an abundance of high-quality data has demonstrated the efficacy of endovascular thrombectomy for improving clinical outcomes in patients with LVOs, transforming the treatment algorithm for affected patients. In this review, we discuss the epidemiology, pathophysiology, natural history, and clinical presentation of LVOs as a framework for understanding the recent clinical strides of the endovascular era.

Mechanical thrombectomy for basilar artery occlusion: efficacy, outcomes, and futile recanalization in comparison with the anterior circulation

BACKGROUND

Performing mechanical thrombectomy (MT) in patients with basilar artery occlusion (BAO) is currently not evidence-based.

OBJECTIVE

To compare patients' outcome, relative merits of achieving recanalization, and predictors of futile recanalization (FR) between BAO and anterior circulation large vessel occlusion (ACLVO) MT.

METHODS

In the multicenter BEYOND-SWIFT registry (NCT03496064), univariate and multivariate (displayed as adjusted Odds Ratios, aOR and 95% confidence intervals, 95%-CI) outcome comparisons between BAO (N=165) and ACLVO (N=1574) were performed. The primary outcome was favorable outcome at 90 days (modified Rankin Scale, mRS 0-2). Secondary outcome included mortality, symptomatic intracranial hemorrhage (sICH) and FR. The relative merits of achieving successful recanalization between ACLVO and BAO were evaluated with interaction terms.

RESULTS

MT in BAO was more often technically effective and equally safe in regards to mortality and sICH when compared to ACLVO. When adjusting for baseline differences, there was no significant difference between BAO vs ACLVO regarding rates of favorable outcome (aOR 0.986, 95%-CI 0.553 - 1.758). However, BAO were associated with increased rates of FR (aOR 2.146, 95%-CI 1.267 - 3.633). Predictors for FR were age, stroke severity, maneuver count and intracranial stenting. No significant heterogeneity on the relative merits of achieving successful recanalization on several outcome parameters were observed when comparing BAO and ACLVO.

CONCLUSIONS

In selected patients, similar outcomes can be achieved in BAO and ACLVO patients treated with MT. Randomized controlled trials comparing patient selection and interventional strategies seem warranted to avoid FR.

TRIAL REGISTRATION NUMBER

NCT03496064.

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.