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.

Posterior circulation ischaemic stroke diagnosis and management

This narrative review provides an overview of the posterior circulation and the clinical features of common posterior circulation stroke (PCS) syndromes in the posterior arterial territories and how to distinguish them from mimics. We outline the hyperacute management of patients with suspected PCS with emphasis on how to identify those who are likely to benefit from intervention based on imaging findings. Finally, we review advances in treatment options, including developments in endovascular thrombectomy (EVT) and intravenous thrombolysis (IVT), and the principles of medical management and indications for neurosurgery. Observational and randomised clinical trial data have been equivocal regarding EVT in PCS, but more recent studies strongly support its efficacy. There have been concomitant advances in imaging of posterior stroke to guide optimal patient selection for thrombectomy. Recent evidence suggests that clinicians should have a heightened suspicion of posterior circulation events with the resultant implementation of timely, evidence-based management.

Prognostic value of pretreatment diffusion-weighted imaging score for acute basilar artery occlusion with successful endovascular recanalization

PURPOSE

The aim of this study is to test the prognostic value of a diffusion-weighted imaging (DWI) score in acute basilar artery occlusion (ABAO) with successful recanalization.

METHODS

The DWI-based pons-midbrain and thalamus (PMT) score was developed to assess posterior circulation infarcts. We test its prognostic value and compare it with other two established scales, the DWI-based posterior circulation acute stroke prognosis Early CT score (PC-ASPECTS) and brain stem score (BSS). A retrospective cohort of consecutive ABAO patients with pretreatment magnetic resonance imaging and successful recanalization (defined as modified Thrombolysis in Cerebral Infarction 2b-3) were analyzed. A favorable outcome was defined as a 90-day modified Rankin Scale (mRS) score of 2 or less. The prognostic performance of three scales was estimated by receiver operating characteristic (ROC) curve analyses.

RESULTS

One hundred and sixteen eligible patients (mean age, 59.1 ± 11.7 [standard deviation]; 96 [82.8%] man) were included and evaluated. Between favorable (mRS ≤ 2) and unfavorable groups, the baseline PMT score (median [interquartile range], 3 [1-4] versus 6 [5-8]; P < 0.001) differs significantly. ROC curve analyses showed the PMT score had the best prognostic value for favorable outcome (area under the curve, PMT versus BSS versus PC-ASPECTS = 0.80 versus 0.72 versus 0.68, P = 0.010). Multivariate logistic regression analyses showed baseline National Institute of Health stroke scale (OR, 0.90 [95%CI, 0.86-0.95], P = 0.004) and PMT score < 5 (OR, 17.83 [95%CI, 3.91-81.19], P < 0.001) were independent prognostic factors of favorable outcome.

CONCLUSIONS

The PMT score seems to predict clinical outcome of ABAO patients with successful recanalization.

A visualized nomogram to online predict futile recanalization after endovascular thrombectomy in basilar artery occlusion stroke

Background and purpose

Futile recanalization occurs in a significant proportion of patients with basilar artery occlusion (BAO) after endovascular thrombectomy (EVT). Therefore, our goal was to develop a visualized nomogram model to early identify patients with BAO who would be at high risk of futile recanalization, more importantly, to aid neurologists in selecting the most appropriate candidates for EVT.

Methods

Patients with BAO with EVT and the Thrombolysis in Cerebral Infarction score of ≥2b were included in the National Advanced Stroke Center of Nanjing First Hospital (China) from October 2016 to June 2021. The exclusion criteria were lacking the 3-month Modified Rankin Scale (mRS), age &lt;18 years, the premorbid mRS score &gt;2, and unavailable baseline CT imaging. Potential predictors were selected for the construction of the nomogram model and the predictive and calibration capabilities of the model were assessed.

Results

A total of 84 patients with BAO were finally enrolled in this study, and patients with futile recanalization accounted for 50.0% (42). The area under the curve (AUC) of the nomogram model was 0.866 (95% CI, 0.786–0.946). The mean squared error, an indicator of the calibration ability of our prediction model, was 0.025. A web-based nomogram model for broader and easier access by clinicians is available online at https://trend.shinyapps.io/DynNomapp/.

Conclusion

We constructed a visualized nomogram model to accurately and online predict the risk of futile recanalization for patients with BAO, as well as assist in the selection of appropriate candidates for EVT.

The safety and effectiveness of endovascular treatment for patients with vertebrobasilar artery occlusions: according to the BEST and BASICS criteria

Background:

Whether endovascular treatment (EVT) is safe and effective for vertebrobasilar artery occlusion (VBAO) is yet incompletely understood. Two RCTs, the endovascular treatment versus standard medical treatment for vertebrobasilar artery occlusion (BEST) trail and the Basilar Artery International Cooperation Study (BASICS), concentrating on this field were recently reported.

Objective:

We use real-world registry data of VBAO to compare the outcome of EVT inside and outside the inclusion and exclusion criteria of the BEST and BASICS study to testify the feasibility of the selection paradigms of VBAO in these trials.

Methods:

Consecutive patients with VBAO receiving EVT involving 21 stroke centers were retrospectively included. The safety outcomes [3-month mortality, symptomatic intracranial hemorrhage (sICH), and effectiveness outcomes (the proportion of 3-month functional independence (mRS of 0–2) and favorable outcome (mRS of 0–3)] were compared between VBAO patients who meet or failed to meet the BEST/BASICS selection criteria for EVT.

Results:

Our study cohort consisted of 577 VBAO patients who underwent EVT. Of them, 446 patients had pc-ASPECTS ≧8. Successful reperfusion (mTICI 2b or 3) was achieved in 85.4% (n = 493). There were 418 patients fulfilling the BEST criterion for EVT and 194 fulfilling the BASICS criterion. Regression analysis indicated that adherence to BEST or BASICS criterion for EVT was not independently related to most of the safety and effectiveness outcome except that adherence to BEST was significantly associated with the 3-month favorable outcome (OR_BEST: 1.742, 95% CI: 1.087–2.790). However, when we put pc-ASPECTS into both criteria with a cut-off value of 8, meeting both BEST criterion plus pc-ASPECTS and BASICS criterion plus pc-ASPECTS was independently related to 3-month functional independence (OR_BEST: 1.687, 95% CI: 1.077–2.644; OR_BASIC: 1.653, 95% CI: 1.038–2.631) and favorable outcome (OR_BEST: 2.280, 95% CI: 1.484–3.502; OR_BASIC: 2.153, 95% CI: 1.372–3.378).

Conclusion:

Our study indicated that, based on real-world data of EVT, adherence to BEST or BASICS criterion for EVT was not independently associated with the safety and effectiveness outcome except that adherence to BEST was significantly related to the 3-month favorable outcome. However, the BEST or BASICS selection criterion and pc-ASPECTS ≧8 might be better paradigms for EVT patient selection.

Outcomes of acute basilar artery occlusion-real-world experience in a middle-income country

OBJECTIVES

Our goal was to describe outcomes in a single-center, real-world series of patients with acute basilar artery occlusion in a middle-income country. In addition, we assessed potential outcome predictors.

MATERIAL AND METHODS

Data from 28 patients were retrospectively reviewed. The primary outcome was death until last follow-up. Other outcomes were rates of favorable outcome until last follow-up and rates of intracranial hemorrhage. Outcomes were compared in subgroups according to several variables, including reperfusion (REP group) or no reperfusion (NOREP group) interventions, with chi-squared, Fisher's exact test, or Mann-Whitney tests.

RESULTS

The rate of overall intrahospital death was 46%. Death until last follow-up occurred in 8/17 (47%) in the REP and in 7/11 (63%) of the NOREP group. Favorable outcomes were observed in 35.7% of the patients: 8/17 (47%) in REP and in 2/11 (18.1%) in NOREP. NIH stroke scale scores were significantly lower in patients with favorable outcomes. Intracranial hemorrhage was observed in 6/28 (21.4%) of the patients (all in REP group). Twenty patients were treated with anticoagulants within the first 24 h. No hemorrhage was observed in those treated with enoxaparin, while three occurred in subjects treated with unfractionated heparin.

CONCLUSION

Together with other series, our results underscore the relevance of NIH stroke scale at admission as a prognostic marker, the importance of reperfusion to improve outcomes, and the need of clinical trials to compare the impact of treatment with anticoagulants within first 24 h in basilar artery occlusion.

Predictive value of DWI posterior-circulation lesion volume for 90-day clinical outcome after endovascular treatment of acute basilar artery occlusion: a retrospective single-center study

PURPOSE

The relationship between posterior-circulation lesion volume (PCLV) and clinical outcomes is poorly investigated. We aimed to analyze, in patients with acute basilar artery occlusion (ABAO), if pre-endovascular treatment (EVT) PCLV was a predictor of outcomes.

METHODS

We analyzed consecutive MRI selected, endovascularly treated ABAO patients. Baseline PCLV was measured in milliliters on apparent diffusion-coefficient map reconstruction. Univariable and multivariable logistic models were used to test if PCLV was a predictor of 90-day outcomes. After the received operating characteristic (ROC) analysis, the optimal cut-off was determined to evaluate the prognostic value of PCLV.

RESULTS

A total of 110 ABAO patients were included. The median PCLV was 4.4 ml (interquartile range, 1.3-21.2 ml). Successful reperfusion was achieved in 81.8% of cases after EVT. At 90 days, 31.8% of patients had a modified Rankin scale ≤ 2, and the mortality rate was 40.9%. PCLV was an independent predictor of functional independence and mortality (odds ratio [OR]:0.57, 95% confidence interval [CI], 0.34-0.93 and 1.84, 95% CI, 1.23-2.76, respectively). The ROC analysis showed that a baseline PCLV ≤ 8.7 ml was the optimal cut-off to predict the 90-day functional independence (area under the curve [AUC] = 0.68, 95% CI, 0.57-0.79, sensitivity 88.6%, and specificity 49.3%). In addition, a PCLV ≥ 9.1 ml was the optimal cut-off for the prediction of 90-day mortality (AUC = 0.71, 95% CI, 0.61-0.82, sensitivity 80%, and specificity 60%).

CONCLUSIONS

Pre-treatment PCLV was an independent predictor of 90-day outcomes in ABAO. A PCLV ≤ 8.7 and ≥ 9.1 ml may identify patients with a higher possibility to achieve independence and a higher risk of death at 90 days, respectively.

Cerebral blood volume index as a predictor of functional independence after basilar artery thrombectomy

BACKGROUND AND PURPOSE

The role of CT perfusion (CTP)in the evaluation of acute basilar artery occlusion (aBAO) patients undergoing endovascular thrombectomy (EVT) is unclear. We investigated the association of individual CTP parameters with functional outcomes in aBAO patients undergoing EVT.

METHODS

A health system's prospectively collected code stroke registry was used in this retrospective analysis of aBAO patients treated with EVT presenting between January 2017 and February 2021 with pre-EVT CTP. The primary outcome measure was modified Rankin Scale (mRS) score 0-2 at 90 days. Factors with a univariate association (p < .05) with mRS 0-2 were combined in a multivariable regression model to determine independent predictors of 90-day favorable functional outcome.

RESULTS

Forty-six subjects, with median age 67 years and median National Institutes of Health Stroke Scale 16, were included, of whom 17 (37%) achieved mRS 0-2 at 90 days. In the multivariable logistic regression model, CTP cerebral blood volume (CBV) index (per 0.1-point increase, odds ratio = 1.843; 95% confidence interval: 1.039, 3.268; p-value .0365) was independently associated with a favorable 90-day outcome.

CONCLUSIONS

CBV index was independently associated with a favorable 90-day outcome in aBAO patients treated with EVT, a novel finding in this patient population. CBV index may assist in treatment and prognosis discussions and inform future studies investigating the role of CTP in aBAO.

Predictors of a Good Outcome in Endovascular Treatment for Basilar Artery Occlusion with a Direct Aspiration First-Pass Technique

Objective

There is limited evidence for mechanical thrombectomy in patients with basilar artery occlusion. Despite recanalization, there are several reports on poor outcomes. Therefore, we retrospectively evaluated the outcomes and examined the predictors of mechanical thrombectomy in patients with basilar artery occlusion.

Methods

We recruited 22 consecutive patients who had received mechanical thrombectomy for basilar artery occlusion with a direct aspiration first-pass technique at our hospital between January 2016 and April 2020. The subjects were divided into good (modified Rankin Scale [mRS] ≤2) and poor outcome groups (mRS ≥3) and compared with one another. We conducted ROC analysis to identify the cut-off value that revealed a statistically significant difference in the univariate analysis.

Results

Of the 22 patients, the average age ± standard deviation (SD), median pretreatment NIHSS (interquartile range [IQR]), and median pretreatment posterior circulation acute stroke progression early CT score (pc-ASPECTS) (IQR) were 76 ± 10 years, 21 (8-31), and 8 (5-9), respectively. The predictors that showed statistically significant differences in the univariate analysis were age, pretreatment NIHSS score, and pretreatment pc-ASPECTS. Based on the ROC analysis, age (area under the curve [AUC] of 0.782, cutoff <74, and P = 0.028), pretreatment pc-ASPECTS (AUC of 0.850, cutoff ≥7, and P = 0.006), and pretreatment NIHSS (AUC of 0.803, cutoff <19, and P = 0.018) were significant prognostic factors.

Conclusion

In this study, aged <74 years, pc-ASPECTS ≥7, and NIHSS <19 were significant prognostic factors in endovascular treatment for basilar artery occlusion with a direct aspiration first-pass technique.

Comparison of Risk Factors, Safety, and Efficacy Outcomes of Mechanical Thrombectomy in Posterior vs. Anterior Circulation Large Vessel Occlusion

Background and Purpose: It is believed that stroke occurring due to posterior circulation large vessel occlusion (PCLVO) and that occurring due to anterior circulation large vessel occlusion (ACLVO) differ in terms of their pathophysiology and the outcome of their acute management in relation to endovascular mechanical thrombectomy (MT). Limited sample size and few randomized controlled trials (RCTs) with respect to PCLVO make the safety and efficacy of MT, which has been confirmed in ACLVO, difficult to assess in the posterior circulation. We therefore conducted a meta-analysis to study to which extent MT in PCLVO differs from ACLVO. Materials and Methods: We searched the databases PubMed, Cochrane, and EMBASE for studies published between 2010 and January 2021, with information on risk factors, safety, and efficacy outcomes of MT in PCLVO vs. ACLVO and conducted a systematic review and meta-analysis; we compared baseline characteristics, reperfusion treatment profiles [including rates of intravenous thrombolysis (IVT) and onset-to-IVT and onset-to-groin puncture times], recanalization success [Thrombolysis In Cerebral Infarction scale (TICI) 2b/3], symptomatic intracranial hemorrhage (sICH), and favorable functional outcome [modified Rankin Score (mRS) 0-2] and mortality at 90 days. Results: Sixteen studies with MT PCLVO (1,172 patients) and ACLVO (7,726 patients) were obtained from the search. The pooled estimates showed higher baseline National Institutes of Health Stroke Scale (NIHSS) score (SMD 0.32, 95% CI 0.15-0.48) in the PCLVO group. PCLVO patients received less often IVT (OR 0.65, 95% CI 0.53-0.79). Onset-to-IVT time (SMD 0.86, 95% CI 0.45-1.26) and onset-to-groin puncture time (SMD 0.59, 95% CI 0.33-0.85) were longer in the PCLVO group. The likelihood of obtaining successful recanalization and favorable functional outcome at 90 days was comparable between the two groups. PCLVO was, however, associated with less sICH (OR 0.56, 95% CI 0.37-0.85) but higher mortality (OR 1.92, 95% CI 1.46-2.53). Conclusions: This meta-analysis indicates that MT in PCLVO may be comparably efficient in obtaining successful recanalization and 90 day favorable functional outcome just as in ACLVO. Less sICH in MT-treated PCLVO patients might be the result of the lower IVT rate in this group. Higher baseline NIHSS and longer onset-to-IVT and onset-to-groin puncture times may have contributed to a higher 90 day mortality in PCLVO patients.

Comatose With Basilar Artery Occlusion: Still Odds of Favorable Outcome With Recanalization Therapy

Background: Around 30–60% of patients with basilar artery occlusion (BAO) present with coma, which is often considered as a hallmark of poor prognosis.

Aim: To examine factors that will help predict outcomes in patients with BAO comatose on admission.

Methods: A total of 312 patients with angiography-proven BAO were analyzed. Comas were assessed as Glasgow Coma Scale (GCS) of ≤8 or impaired level of consciousness ascertained in the medical records. Outcomes were evaluated with the modified Rankin Scale (mRS) over a phone call at 3 months. In our study, 53 patients were excluded due to inadequate data on the level of consciousness.

Results: In total, 103/259 (39.8%) of BAO patients were comatose on admission. Factors associated with acute coma were higher age, coronary artery disease, convulsions, extent of early ischemia by posterior circulation Acute Stroke Prognosis Early CT Score (pc-ASPECTS) < 8, absence of patent posterior collateral vasculature, and occlusion over multiple segments of BA. A total of 21/103 (20.4%) of comatose patients had a favorable outcome (mRS 0–3), and 12/103 (11.7%) had a good outcome (mRS 0–2). Factors associated with a favorable outcome in comatose BAO patients were younger age (p = 0.010), less extensive baseline ischemia (p = 0.027), recanalization (p = 0.013), and avoiding symptomatic intracranial hemorrhage (sICH) (p = 0.038). Factors associated with the poorest outcome or death (mRS 5–6) were older age (p = 0.001), diabetes (p = 0.022), atrial fibrillation (p = 0.016), lower median GCS [4 (IQR 3.6) vs. 6 (5–8); p = 0.006], pc-ASPECTS < 8 (p = 0.003), unsuccessful recanalization (p = 0.006), and sICH (p = 0.010). Futile recanalization (mRS 4–6) was significantly more common in comatose patients (49.4 vs. 18.5%, p < 0.001).

Conclusions: One in five BAO patients with acute coma had a favorable outcome. Older patients with cardiovascular comorbidities and already existing ischemic lesions before reperfusion therapies tended to have a poor prognosis, especially if no recanalization is achieved and sICH occurred.

[Endovascular treatment of acute basilar artery occlusions]

BACKGROUND

Since the publication of the large randomized controlled thrombectomy trials, endovascular treatment (EVT) has become the standard of care for acute stroke patients with anterior circulation large vessel occlusion (acLVO); however, the treatment of patients with an intracranial occlusion in the posterior circulation and in particular of the basilar artery has not been proven. Thus, there is uncertainty regarding the indications for EVT due to the poor evidence situation.

OBJECTIVE

This review article addresses the current data on EVT in the posterior circulation and the most recent study results. Furthermore, the pathophysiological aspects, indications and specific features in the treatment of these patients are also discussed.

RESULTS

Despite limited evidence for EVT, this treatment modality has gained significant clinical relevance for the treatment of stroke patients with vascular occlusions in the posterior circulation. From a technical point of view, vascular occlusions in the posterior circulation and particularly of the basilar artery are easily accessible, although the etiology of occlusions and necessary techniques differ compared to occlusions in the anterior circulation.

CONCLUSION

Compared to acLVO, EVT in the posterior circulation differs with respect to the current evidence, indications and technique. As current data have not proven its effectiveness for improved clinical outcome, treatment decisions must still be made individually based on institutional protocols, particularly for patients in the late time window or for patients already with signs of extensive infarction on baseline imaging.

Posterior circulation acute stroke prognosis early CT scores in predicting functional outcomes: A meta-analysis

Background and purpose

Patients with posterior circulation acute ischemic stroke exhibit varied clinical presentations and functional outcomes. Whether posterior circulation acute stroke prognosis early computed tomography scores (PC-ASPECTS) predict unfavorable functional outcomes (UFO) for patients treated with different therapeutic regimens is unclear.

Methods

According to PRISMA guidelines, we performed a systematic search of electronic databases for studies assessing the functional outcomes of posterior circulation acute ischemic stroke using baseline PC-ASPECTS. The following three scales of PC-ASPECTS were retrieved: UFO prediction by using PC-ASPECTS per score decrease, UFO prediction by using binary PC-ASPECTS with a cut-off value, and the difference in PC-ASPECTS between patients with unfavorable and favorable functional outcomes. Moreover, a subgroup analysis was conducted for patients treated with intra-arterial endovascular treatment (IA-EVT) only. Sensitivity analysis with different definition of UFO and image modalities were also conducted.

Results

In total, 25 studies were included. In scale 1, PC-ASPECTS significantly predicted UFO (odds ratio [OR]: 1.66 per score decrease, 95% confidence interval [CI]: 1.32–2.07). In scale 2, binary PC-ASPECTS with a cut-off value between 6 and 9 significantly predicted UFO (OR: 3.91, 95% CI: 2.54–6.01). In scale 3, patients with UFO had lower PC-ASPECTS than those with favorable outcomes (standardized mean difference [SMD]: −0.67, 95% CI: −0.8 to −0.55). For patients treated with IA-EVT only, the scales demonstrated consistent results. Sensitivity analysis showed PC-ASPECTS significantly predicted UFO in both definitions of modified Rankin Scale ≥ 3 and ≥ 4, and magnetic resonance imaging was preferred imaging modality for PC-ASPECTS evaluation.

Conclusion

Baseline PC-ASPECTS is effective in predicting UFO for patients with posterior circulation acute ischemic stroke treated with different therapeutic regimens.

Multimodal CT pc-ASPECTS in infratentorial stroke: diagnostic and prognostic value

BACKGROUND AND PURPOSE

Diagnosis of posterior circulation stroke may be challenged. National Institutes of Health Stroke Scale (NIHSS) and brain imaging (non-contrast brain computed tomography-CT) are used for diagnosis; evaluation on posterior circulation stroke remains a limit of NIHSS, and the value of non-contrast CT (NCCT) is limited due to artifacts caused by the bones of the base of the skull. We tested the validity and prognostic value of posterior circulation Alberta Stroke Program Early CT Score (pc-ASPECTS) in patients with posterior circulation stroke.

METHODS

Pc-ASPECTS allots the posterior circulation 10 points. We studied 50 patients with posterior circulation stroke. We applied pc-ASPECTS to NCCT, CT angiography, and CT Perfusion. We evaluated the correlation of pc-ASPECT with outcome parameters for stroke.

RESULTS

Out of 50 patients, CTP showed abnormalities in 34 cases. The pc-ASPECT score calculated on brain CT and on the brain CT + angio CT had a sensibility of 24%, calculated on brain CT, angio CT and CTPerfusion gain a sensibility of 72%. Pc-ASPECT MTT resulted to be the more reliable parameter: outcome given by NIHSS score at discharge, mRS at discharge, and at 3 months was more severe in patients with Pc-ASPECT MTT alteration. Outcome given by NIHSS score at discharge and mRS at discharge and 1 at 3 months was more severe in patients with higher NIHSS score at admission.

CONCLUSION

We evaluated the usefulness of pc-ASPECTS on CTP in predicting functional outcome in acute posterior circulation stroke that appears to be a powerful marker for predicting functional outcome.

Values of Baseline Posterior Circulation Acute Stroke Prognosis Early Computed Tomography Score for Treatment Decision of Acute Basilar Artery Occlusion

BACKGROUND AND PURPOSE

This study aimed to analyze the impact of baseline posterior circulation Acute Stroke Prognosis Early Computed Tomography Score (pc-ASPECTS) on the efficacy and safety of endovascular therapy (EVT) for patients with acute basilar artery occlusion.

METHODS

The BASILAR was a nationwide prospective registry of consecutive patients with a symptomatic and radiologically confirmed acute basilar artery occlusion within 24 hours of symptom onset. We estimated the effect of standard medical therapy alone (SMT group) versus SMT plus EVT (EVT group) for patients with documented pc-ASPECTS on noncontrast CT, both as a categorical (0-4 versus 5-7 versus 8-10) and as a continuous variable. The primary outcomes included favorable functional outcomes (modified Rankin Scale ≤3) at 90 days and mortality within 90 days.

RESULTS

In total, 823 cases were included: 468 with pc-ASPECTS 8 to 10 (SMT: 71; EVT: 397), 317 with pc-ASPECTS 5 to 7 (SMT: 85; EVT: 232), and 38 with pc-ASPECTS 0 to 4 (SMT: 13; EVT: 25). EVT was associated with higher rate of favorable outcomes (adjusted relative risk with 95% CI, 4.35 [1.30-14.48] and 3.20 [1.68-6.09]; respectively) and lower mortality (60.8% versus 77.6%, P=0.005 and 35.0% versus 66.2%, P<0.001; respectively) than SMT in the pc-ASPECTS 5 to 7 and 8 to 10 subgroups. Continuous benefit curves also showed the superior efficacy and safety of EVT over SMT in patients with pc-ASPECTS ≥5. Furthermore, the prognostic effect of onset to puncture time on favorable outcome with EVT was not significant after adjustment for pc-ASPECTS (adjusted odds ratio, 0.98 [95% CI, 0.94-1.02]).

CONCLUSIONS

Patients of basilar artery occlusion with pc-ASPECTS ≥5 could benefit from EVT. The baseline pc-ASPECTS appears more important for decision making and predicting prognosis than time to EVT. Registration: URL: http://www.chictr.org.cn. Unique identifier: ChiCTR1800014759.

Acute ischemic stroke endovascular therapy

Endovascular therapy (EVT) has become the standard treatment for large-vessel occlusion (LVO) acute ischemic stroke (AIS). EVT is now indicated in patients up to 24h from their last known well, provided that the patient meets specific clinical and imaging criteria. Improvements in thrombectomy devices, techniques, and operator experience have allowed successful EVT of ICA terminus, M1-MCA occlusions as well as proximal M2-MCA, basilar artery occlusions, and revascularization of tandem lesions. Mechanical thrombectomy failures still occur due to several factors, however, highlighting the need for further device and technical improvements. An ongoing debate exists regarding the need for pre-EVT thrombolytic agents, thrombectomy techniques, distal occlusions, anesthesia methods, the role of advanced neuroimaging, the treatment of patients with larger infarct core, and those presenting with milder stroke symptoms. Many of these questions are the subject of current or upcoming clinical trials. This review aims to provide an outline and discussion about the established recommendations and emerging topics regarding EVT for LVO AIS.

DWI cerebellar infarct volume as predictor of outcomes after endovascular treatment of acute basilar artery occlusion

BACKGROUND

Preprocedural predictors of outcome in patients with acute basilar artery occlusion (ABAO) who have undergone endovascular treatment (EVT) remain controversial. Our aim was to determine if pre-EVT diffusion-weighted imaging cerebellar infarct volume (CIV) is a predictor of 90-day outcomes.

METHODS

We analyzed consecutive MRI-selected endovascularly treated patients with ABAO within the first 24 hours after symptom onset. Successful reperfusion was defined as a modified Thrombolysis in Cerebral Infarction score of 2b-3. Using the initial MRI, baseline CIV was calculated in mL on an apparent diffusion coefficient map reconstruction (Olea Sphere software). CIV was analyzed in univariate and multivariable models as a predictor of 90-day functional independence (modified Rankin Scale (mRS) 0-2) and mortality. According to receiver operating characteristic (ROC) analysis, the optimal cut-off was determined by maximizing the Youden index to evaluate the prognostic value of CIV.

RESULTS

Of the 110 MRI-selected patients with ABAO, 64 (58.18%) had a cerebellar infarct. The median CIV was 9.6 mL (IQR 2.7-31.4). Successful reperfusion was achieved in 81.8% of the cases. At 90 days the proportion of patients with mRS ≤2 was 31.8% and the overall mortality rate was 40.9%. Baseline CIV was significantly associated with 90-day mRS 0-2 (p=0.008) in the univariate analysis and was an independent predictor of 90-day mortality (adjusted OR 1.79, 95% CI 1.25 to 2.54, p=0.001). The ROC analysis showed that a CIV ≥4.7 mL at the initial MRI was the optimal cut-off to discriminate patients with a higher risk of death at 90 days (area under the ROC curve (AUC)=0.74, 95% CI 0.61 to 0.87, sensitivity and specificity of 87.9% and 58.1%, respectively).

CONCLUSIONS

In our series of MRI-selected patients with ABAO, pre-EVT CIV was an independent predictor of 90-day mortality. The risk of death was increased for baseline CIV ≥4.7 mL.

Prediction of Infarct Growth and Neurological Deterioration in Patients with Vertebrobasilar Artery Occlusions

We aimed to identify predictors of infarct growth and neurological deterioration (ND) in vertebrobasilar occlusions (VBOs) with a focus on clinical-core mismatch. From 2010 to 2018, VBO patients were selected from a university hospital registry. In total, 138 VBO patients were included. In these patients, a posterior circulation Alberta Stroke Program Early CT score (PC-ASPECTS) less than 6 was associated with futile outcome. Within patients with feasible cores, a decrease in PC-ASPECTS score of 2 or more on follow-up imaging was classified as infarct growth and could be predicted by a National Institutes of Health Stroke Scale (NIHSS) mental status subset of 1 or higher (odds ratio (OR): 3.34, 95% confidence interval (CI) (1.19-9.38), p = 0.022). Among the 73 patients who did not undergo reperfusion therapy, 13 patients experienced ND (increase in discharge NIHSS score of 4 or more compared to the initial presentation). Incomplete occlusion (vs. complete occlusion, OR 6.17, 95% CI (1.11-34.25), p = 0.037), poorer collateral status (BATMAN score, OR: 1.91, 95% CI (1.17-3.48), p = 0.009), and larger infarct cores (PC-ASPECTS, OR: 1.96, 95% CI (1.11-3.48), p = 0.021) were predictive of ND. In patients with VBO, an initial PC-ASPECTS of 6 or more, but with a decrease in the mental status subset of 1 or more can predict infarct growth, and may be used as a criterion for clinical-core mismatch. ND in VBO patients presenting with milder symptoms can be predicted by incomplete occlusion, poor collaterals, and larger infarct cores.

Rapid Successful Reperfusion of Basilar Artery Occlusion Strokes With Pretreatment Diffusion-Weighted Imaging Posterior-Circulation ASPECTS <8 Is Associated With Good Outcome

Background

The association between time to reperfusion and clinical outcome is well known in anterior circulation strokes, whereas the impact of main time metrics remains unknown in posterior circulation strokes. We investigated the clinical effect of different time intervals from symptom onset to reperfusion on the 90‐day clinical outcome in acute ischemic stroke patients with basilar artery occlusion, and especially in the subset population presenting a low stroke volume on baseline diffusion‐weighted imaging.

Methods and Results

We studied patients included in the prospective, multicenter, observational ETIS (Endovascular Treatment in Ischemic Stroke) registry who had had basal artery occlusion and had achieved successful reperfusion (modified Thrombolysis In Cerebral Infarction 2b‐3). Three time intervals (onset to reperfusion, onset to imaging, and imaging to reperfusion) were considered in all patients and separately in patients with pc‐ASPECTS (posterior‐circulation Alberta Stroke Program Early Computed Tomography Score) <8 and ≥8 on baseline diffusion‐weighted imaging. The primary end point was good outcome defined as 90‐day modified Rankin Scale scores of 0 to 2. Among the 95 included patients, 38 (40%) achieved a good outcome. In all patients, no significant association was found between the different time intervals and outcome. In patients evaluated with diffusion‐weighted imaging (n=61) at baseline, a significant negative association was found between imaging‐to‐reperfusion time for patients with pc‐ASPECTS <8 (adjusted odds ratio=0.4 per 30‐minute increase; 95% CI 0.18‐0.85; P=0.02) compared with those with pc‐ASPECTS ≥8.

Conclusions

In patients with basilar artery occlusion and pc‐ASPECTS <8 at baseline diffusion‐weighted imaging, clinical outcome is highly dependent on the time from imaging to reperfusion, which suggests that rapid endovascular reperfusion should be performed after imaging in these patients.

Predicting outcomes after acute reperfusion therapy for basilar artery occlusion

BACKGROUND AND PURPOSE

Basilar artery occlusion (BAO) leads to high rates of morbidity and mortality, despite successful recanalization. The discordance between flow restoration and long-term functional status clouds clinical decision-making regarding further aggressive care. We sought to develop and validate a practical, prognostic tool for the prediction of 3-month favorable outcome after acute reperfusion therapy for BAO.

METHODS

This retrospective, multicenter, observational study was conducted at four high-volume stroke centers in the USA and Europe. Multivariate regression analysis was performed to identify predictors of favorable outcome (90-day modified Rankin scale scores 0-2) and derive a clinically applicable prognostic model (the Pittsburgh Outcomes after Stroke Thrombectomy-Vertebrobasilar (POST-VB) score). The POST-VB score was evaluated and internally validated with regard to calibration and discriminatory ability. External validity was assessed in patient cohorts at three separate centers.

RESULTS

In the derivation cohort of 59 patients, independent predictors of favorable outcome included smaller brainstem infarct volume on post-procedure magnetic resonance imaging (P < 0.01) and younger age (P = 0.01). POST-VB score was calculated as: age + (10 × brainstem infarct volume). POST-VB score demonstrated excellent discriminatory ability [area under the receiver-operating characteristic curve (AUC) = 0.91] and adequate calibration (P = 0.88) in the derivation cohort (Center A). It performed equally well across the three external validation cohorts (Center B, AUC = 0.89; Center C, AUC = 0.78; Center D, AUC = 0.80). Overall, a POST-VB score < 49 was associated with an 88% likelihood of favorable outcome, as compared to 4% with a score ≥ 125.

CONCLUSIONS

The POST-VB score effectively predicts 3-month functional outcome following acute reperfusion therapy for BAO and may aid in guiding post-procedural care.

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.

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.

Current endovascular strategies for posterior circulation large vessel occlusion stroke: report of the Society of NeuroInterventional Surgery Standards and Guidelines Committee

Background

The aim of this publication is to provide a detailed update on the diagnosis, treatment, and endovascular techniques for posterior circulation emergent large vessel occlusion (pc-ELVO).

Methods

We performed a review of the literature to specifically evaluate this disease and its treatments.

Results

Data were analyzed, and recommendations were reported based on the strength of the published evidence and expert consensus.

Conclusion

While many questions about pc-ELVO remain to be studied, there is evidence to support particular practices in its evaluation and treatment.

Mechanical thrombectomy in basilar artery occlusion: influence of reperfusion on clinical outcome and impact of the first-line strategy (ADAPT vs stent retriever)

OBJECTIVESeveral randomized trials have been focused on patients with anterior circulation stroke, whereas few data on posterior circulation stroke are available. Thus, new mechanical thrombectomy (MT) strategies, including a direct-aspiration first-pass technique (ADAPT), remain to be evaluated in basilar artery occlusion (BAO) patients. The authors here assessed the influence of reperfusion on outcome in BAO patients and examined whether ADAPT improves the reperfusion rate compared with stent retriever devices.METHODSThree comprehensive stroke centers prospectively collected individual data from BAO patients treated with MT. Baseline characteristics as well as radiographic and clinical outcomes were compared between the 2 MT strategies. The primary outcome measure was the rate of successful reperfusion, defined as a modified Thrombolysis in Cerebral Infarction (mTICI) grade of 2b-3. Favorable outcome was defined as a 90-day modified Rankin Scale score of 0-2.RESULTSAmong the 100 adult patients included in the study, 46 were treated with first-line ADAPT (median age 61 years, IQR 53-71 years; stent-retriever rescue therapy was secondarily used in 12 [26.1%]) and 54 were treated with a primary stent retriever (median age 67 years, IQR 53-78 years). There was no difference in baseline characteristics between the 2 treatment groups, except for the rate of diabetes (19.6% vs 5.7%, respectively, p = 0.035). Successful reperfusion was achieved in 79% of the overall study sample. Overall, the rate of favorable outcome was 36.8% and 90-day all-cause mortality was 44.2%. Successful reperfusion positively impacted favorable outcome (OR 4.57, 95% CI 1.24-16.87, p = 0.023). A nonsignificant trend toward a higher successful reperfusion rate (unadjusted OR 2.56, 95% CI 0.90-7.29, p = 0.071) and a significantly higher rate of complete reperfusion (mTICI grade 3; unadjusted OR 2.59, 95% CI 1.14-5.86, p = 0.021) was found in the ADAPT group. The procedure duration was also significantly lower in the ADAPT group (median 45 minutes, IQR 34 to 62 minutes vs 56 minutes, IQR 40 to 90 minutes; p = 0.05), as was the rate of periprocedural complications (4.3% vs 25.9%, p = 0.003). Symptomatic intracranial hemorrhage (0.0% vs 4.0%, p = 0.51) and 90-day all-cause mortality (46.7% vs 42.0%, p = 0.65) were similar in the 2 groups.CONCLUSIONSAmong BAO patients, successful reperfusion is a strong predictor of a 90-day favorable outcome, and the choice of ADAPT as the first-line strategy achieves a significantly higher rate of complete reperfusion with a shorter procedure duration.

Predictors for Mortality after Mechanical Thrombectomy of Acute Basilar Artery Occlusion

Background: Modern endovascular thrombectomy (MET), using stent retrievers or large-bore distal aspiration catheters in stroke patients with acute basilar artery occlusion (BAO), is routinely performed to date. However, more than 35% of BAO patients treated with MET die within 90 days despite high recanalization rates. The purpose of this study is to investigate the parameters associated with 90-day mortality in patients with BAO after MET. Methods: We analyzed 117 consecutive BAO patients included in the Endovascular Treatment in Ischemic Stroke prospective clinical registry of consecutive acute ischemic stroke patients treated with MET (60 patients [51.3%] treated with a stent retriever as first-line technique) between March 2010 and April 2017. Successful recanalization was defined as modified thrombolysis In cerebral infarction scores 2b-3 at the end of MET, and mortality was defined as modified Rankin Scale 6 at 90 days. Associations of baseline characteristics (patient and treatment characteristics) and intermediate outcomes (recanalization, complications) with 90-day mortality were investigated in univariate and multivariate analyses. Results: Overall successful recanalization rate was 79.5, and 41.9% (95% CI 32.8–51.0%) of patients died within 90 days after MET. Patients with successful recanalization had a lower mortality rate (32.9 vs. 74.4%; p < 0.001). Failure of successful recanalization was an independent predictor of mortality (OR 5.1; 95% CI 1.34–19.33). In multivariate analysis, age ≥60 years (OR 6.37; 95% CI 1.74–23.31), admission National Institute of Health Stroke Scale (NIHSS) ≥13 (OR 4.62; 95% CI 1.42–15.03), lower posterior circulation-Alberta Stroke Program Early CT Score (pc-ASPECTS; OR 1.71; 95% CI 1.19–2.44), use of antithrombotic medication prior to stroke onset (OR 3.38; 95% CI 1.03–11.08), absence of intravenous thrombolysis (OR 3.36; 95% CI 1.12–10.03), and angioplasty/stenting of the basilar artery (OR 4.71; 95% CI 1.34–16.54) were independent predictors for mortality after MET. Conclusions: Failure of successful recanalization was a strong predictor for mortality. In the setting of recanalization, age, admission NIHSS, pc-ASPECTS, absence of intravenous thrombolysis, and angioplasty/stenting of the basilar artery were also independent predictors for mortality after MET of BAO patients.

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

Triage of posterior circulation stroke from emergent large-vessel occlusion (pc-ELVO) is challenging owing to the stuttering clinical course and potential for rapid decline. Growing clinical data support the use of mechanical thrombectomy in pc-ELVO, but there are limited data addressing the clinical and imaging criteria for patient selection. We present our triage algorithm used to select patients for endovascular therapy (EVT) in the setting of pc-ELVOS. We use a consecutive retrospective database from 2004 to 2016 to describe the practice patterns and prognostic factors for pc-ELVO patients treated using both medical and EVT. Patients with moderate to severe deficits (NIHSS > 10) did better when they received EVT ( p < 0.03), whereas patients with stable, mild deficits (NIHSS ≤ 10) did well (90% favorable outcome) regardless of treatment type. Roughly one-third of patients presenting with mild deficits deteriorated to moderate to severe deficits (NIHSS > 10), most of whom subsequently received EVT (9 of 12), with 56% favorable outcomes. Cerebellar and brainstem infarct volumes were independent imaging predictors of outcome. These results can be used to define triage criteria for use of EVT in pc-ELVO in future practice and clinical trials.

Cerebral blood volume lesion extent predicts functional outcome in patients with vertebral and basilar artery occlusion

Background

CT perfusion may improve diagnostic accuracy in posterior circulation stroke. The posterior circulation Acute Stroke Prognosis Early CT score (pc-ASPECTS) on Computed Tomography Angiography source images (CTA-SI) predicts functional outcome in patients with basilar artery occlusion.

Aims

We assessed the prognostic value of pc-ASPECTS on CT perfusion in patients with vertebral and basilar artery occlusion (VBAO) in comparison with CTA-SI.

Methods

Whole-brain CT perfusion from consecutive stroke patients with VBAO at four stroke centers was retrospectively analyzed. pc-ASPECTS – a 10-point score assessing hypoattenuation on CTA-SI – was calculated from CT perfusion parameters as focally reduced cerebral blood flow or cerebral blood volume, focally increased time to peak of the deconvolved tissue residue function (Tmax) or mean transit time. Two investigators independently reviewed the images. Reliability was assessed with intraclass correlation coefficient. Good outcome was defined as modified Rankin scale ≤3 at three months.

Results

We included 60 patients with VBAO. After assessment of four CT perfusion maps simultaneously, area-under-ROC curve (AROC) was 0.83 (95%CI 0.72–0.93) for cerebral blood volume, 0.76 (95%CI 0.64–0.89) for cerebral blood flow, 0.77 (95%CI 0.64–0.89) for Tmax, 0.70 (95%CI 0.56–0.84) for mean transit time versus area-under-ROC curve 0.64 (95%CI 0.50–0.79) for CTA-SI. Cerebral blood volume had greater accuracy compared with CTA-SI for poor outcome (p = 0.04). In logistic regression analysis, cerebral blood volume pc-ASPECTS≤8 was independently associated with poor outcome (OR 9.3 95%CI 2.2–41; p = 0.003, adjusted for age and clinical severity). Inter-rater agreement was substantial for cerebral blood volume pc-ASPECTS (intraclass correlation coefficient 0.82 95%CI 0.71–0.90 versus 0.67 for CTA-SI 95%CI 0.43–0.81).

Conclusions

Cerebral blood volume pc-ASPECTS may identify VBAO patients at higher risk of disability.

[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.

Neuroimaging Predictors of Clinical Outcome in Acute Basilar Artery Occlusion

Certain early neuroimaging findings are independent predictors of clinical outcome in acute basilar artery occlusion. These imaging findings may serve as important baseline imaging characteristics as well as subgroups in future randomized controlled trials. The purpose of this review is to review and compare early neuroimaging findings seen on non-invasive cranial imaging that predict clinical outcome in acute basilar artery occlusion.

Case Report of False-Negative Diffusion-Weighted Image of Brain Maggnetic Resonance Imaging (MRI) in Acute Ischemic Stroke

Patient: Male, 75

Final Diagnosis: Acute ischemic stroke

Symptoms: Dizziness • unsteady gait

Medication: —

Clinical Procedure: None

Specialty: Radiology

Functional Independence following Endovascular Treatment for Basilar Artery Occlusion despite Extensive Bilateral Pontine Infarcts on Diffusion-Weighted Imaging: Refuting a Self-Fulfilling Prophecy

BACKGROUND AND PURPOSE

Extensive brainstem diffusion-weighted imaging (DWI) hyperintensity has been associated with poor outcomes. We aim at documenting a series of patients with extensive DWI pontine lesions who achieved independence following endovascular therapy and aggressive medical therapy in the setting of posterior circulation basilar artery occlusion (BAO).

METHODS

This is a retrospective endovascular database review of a single-operator experience over a 9-year period for patients with (1) complete BAO, (2) extensive bilateral pontine DWI changes and (3) 90-day modified Rankin scale 0-2.

RESULTS

Three out of a total of 40 patients met the inclusion criteria. Case 1 was an 18-year-old male with National Institutes of Health Stroke Scale (NIHSS) 32 on admission, treated 25 h after symptom onset. Case 2 was a 56-year-old male with NIHSS 19, treated 10 h after onset. Case 3 was a 73-year-old male with NIHSS 29, treated 6 h after onset. Full endovascular reperfusion was achieved in all 3 patients. A literature review identified 9 additional cases of extensive pontine DWI changes and good outcome. These patients were young (32 ± 22 years), mostly males (69%), presented with a relatively low posterior circulation Acute Stroke Prognosis Early CT Score (6 ± 1), were treated relatively late from last known normal (13 ± 10 h) and were mostly (84%) treated with endovascular intervention.

CONCLUSION

Extensive bilateral pontine DWI lesions among patients with BAO are not an unequivocal indicator of poor prognosis. We advise strong caution when considering these findings in the treatment decision algorithm.

Outcomes of stent retriever thrombectomy in basilar artery occlusion: an observational study and systematic review

BACKGROUND

Basilar artery occlusion (BAO) remains one of the most devastating subtypes of stroke with high mortality and poor outcome. Early recanalisation is the most powerful predictor of favourable outcome in patients with stroke, and may be improved with mechanical thrombectomy using stent retriever devices. However, the benefit in functional outcome and safety of stent retrievers are not yet well known. The aim of this study was to assess efficacy and safety profiles of stent retriever thrombectomy in BAO patients with stroke.

METHODS

We analysed data retrospectively from our consecutive clinical series and conducted a systematic review and meta-analysis of all previous studies of stent retriever thrombectomy in BAO patients with stroke between November 2010 and April 2014.

RESULTS

From March 2010 to March 2013, 22 patients with acute BAO were treated with a Solitaire stent retriever in our series. Favourable outcome was significantly associated with younger age and distal BAO. The literature search identified 15 previous studies involving a total of 312 subjects. In the meta-analysis, including our series data, the recanalisation rate (Thrombolysis In Cerebral Infarction (TICI) score ≥ 2b) reached 81% (95% CI 73% to 87%). The rate of symptomatic intracranial haemorrhage was 4% (95% CI 2% to 8%), favourable outcome (modified Rankin Scale (mRS) ≤ 2 at 3 months) was found in 42% (95% CI 36% to 48%) and mortality rate was 30% (95% CI 25% to 36%).

CONCLUSIONS

Stent retriever thrombectomy is a safe treatment modality for patients with stroke presenting with BAO. Although the stent retrievers showed a good recanalisation rate, there are currently no randomised clinical trials to assess its clinical efficacy in comparison with the reference treatment.

Recanalization treatments in basilar artery occlusion-Systematic analysis

Background and aims

Basilar artery occlusion is a most devastating form of stroke, and the current practice is to reverse it with revascularization therapies. Pharmacological thrombolysis, intravenous or intraarterial, has been adjuncted or replaced with invasive, endovascular thrombectomy procedures. The preferred approach remains unknown and many recanalizations are futile with no clinical benefit. We sought to determine reasons for futility and weigh the existing reports to find whether endovascular mechanical interventions provide superior outcomes over pharmacological thrombolysis alone.

Methods

After analyzing systematically the reports of outcomes produced by variable basilar artery occlusion recanalization protocols, information was retrieved and reconciled from 15 reports published from year 2005 comprising 803 patients in 17 cohorts. In the largest single-center cohort (162, Helsinki), predictors of futile recanalization (three-month modified Rankin Scale score 4 to 6) were determined.

Results

Good outcome was reported by mechanical approaches either alone or on demand more frequently than by pharmacological, intravenous or intraarterial thrombolysis protocols (35.5% versus 24.4%, p < 0.001), accompanied by higher recanalization rates (84.1% versus 70.9%, p < 0.001). Along with superior recanalization rate at 91%, good outcome was reached by primary thrombectomy in 36% at the cost of substantial futile recanalization rate at 60%, which was lower when using modern stentrievers only (52.8%). In the Helsinki cohort, the single most significant predictor was extensive baseline ischemia, increasing the odds of futility 20-fold (95%CI 4.39-92.29, p < 0.001). Other attributes of futility were ventilation support and history of atrial fibrillation or previous stroke.

Conclusions

Endovascular mechanical approaches have been reported to provide superior outcomes over pharmacological thrombolysis in basilar artery occlusion. Stricter patient selection, most notably to exclude victims of already extended ischemia, would assist in translating excellent recanalization rates into improved clinical outcomes and more acceptable futility rates.

Initial factors affecting the clinical outcome after successful recanalization via MR-based mechanical thrombectomy in patients with acute ischemic stroke due to basilar artery occlusion

Background and purpose

To determine the initial factors, including patient characteristics, stroke etiology and severity, time factors, and imaging findings, that could affect the clinical outcome of patients with acute ischemic stroke (AIS) caused by basilar artery occlusion (BAO) where successful recanalization was achieved via mechanical thrombectomy.

Methods

Between March 2011 and December 2014, 35 patients with AIS caused by BAO received MRI/MR angiography-based mechanical thrombectomies, and recanalization was achieved with a Thrombolysis In Cerebral Infarction score of >2b. The patients were divided into a good outcome group (n=19), defined as those with a modified Rankin Scale (mRS) score of 0–2 at 3 months after stroke onset, and a poor outcome group (n=16), defined as a mRS score of 3–6. The differences between the groups were analyzed.

Results

Initial National Institutes of Health Stroke Scale (NIHSS) score (good vs poor: 17.9±8.9 vs 27.6±8.5, p=0.003), posterior circulation Acute Stroke Prognosis Early CT Score (pc-ASPECTS) based on initial diffusion-weighted images (DWI) (good vs poor: 7.8±1.6 vs 5.4±1.8, p=0.001), pc-ASPECTS based on contrast staining on the post-thrombectomy control CT (good vs poor: 9.2±1.5 vs 6.3±2.2, p<0.001), and presence of contrast staining in the brainstem on that CT (good vs poor: 15.8% vs 81.6%, p<0.001) were significantly different between the groups.

Conclusions

Patients with AIS caused by BAO with a lower initial NIHSS score, fewer lesions on initial DWI, and less contrast staining on the post-thrombectomy control CT have higher probabilities of a good clinical outcome after successful recanalization via a mechanical thrombectomy.

Basilar Occlusion Syndromes: An Update

Basilar artery occlusions (BAOs) are a subset of posterior circulation strokes. Particular issues relevant to BAOs include variable and stuttering symptoms at onset resulting in delays in diagnosis, high morbidity and mortality, and uncertain best management. Despite better imaging techniques, diagnosis, and therefore treatment, is often delayed. We will present the most common signs and symptoms of posterior circulation strokes. Data on optimal treatment strategies are gathered from multiple case series, registries, and one randomized trial, which was stopped early. Possible etiologies of BAOs, acute, and subacute treatment strategies and special topics in neuroimaging of the posterior fossa are discussed. This review may be helpful to neurohospitalists who are managing patients with acute stroke as well as emergency room physicians and neurologists.

Posterior Circulation Acute Stroke Prognosis Early Computed Tomography Score Using Hypointense Vessels on Susceptibility Weighted Imaging Independently Predicts Outcome in Patients with Basilar Artery Occlusion

PURPOSE

Appearance of hypointense vessels on susceptibility weighted imaging (SWI) has been reported to correlate with outcome in patients with ischemia of the anterior circulation. This study investigates the correlation between the appearance of hypointense vessels on SWI after recanalization therapy and outcome in patients with basilar artery occlusion.

METHODS

Patients with basilar artery occlusion who were treated with endovascular recanalization or intravenous alteplase and received an MRI including SWI after therapy were retrieved from the hospital database for retrospective analysis. Posterior circulation Acute Stroke Prognosis Early Computed Tomography Score (pcASPECTS) was calculated based on regions displaying hypointense vessels on SWI and compared to lesions on diffusion weighted imaging (DWI). Subsequently, SWI based pcASPECTS was correlated with outcome determined with modified Rankin Scale (mRS), categorized as favorable outcome (mRS 0-2) or unfavorable outcome (3-6).

RESULTS

Twenty-two MRI of patients with basilar artery occlusion were analyzed. In seven out of eight areas of the pcASPECTS hypointense vessels on SWI were significantly correlated to areas of restricted diffusion on DWI. In univariate analysis median pcASPECTS on SWI was significantly higher in patients with favorable outcome (7.5 vs. 5, p=0.02). In a multivariate analysis pcASPECTS on SWI was an independent predictor of favorable outcome (OR 2.02; CI [1.02;3,99]; p=0.04).

CONCLUSION

pcASPECTS based on hypointense vessels on SWI after therapy predicts outcome in patients with basilar artery occlusion and might potentially be used as an additional imaging biomarker in the management of patients with stroke in the posterior circulation. This needs to be confirmed in larger prospective clinical trials.

Endovascular revascularization for basilar artery occlusion

Basilar artery occlusion is one of the most devastating neurological conditions known to man. Though rare, patients with clinical syndromes localized to this anatomical region are often referred to acute stroke and endovascular units. Recent studies evaluating the efficacy of endovascular approaches to stroke have focused on anterior circulation syndromes. In this review, we examine the approaches to stroke syndromes due to basilar artery thrombosis. We share the relevant data for intravenous and intra-arterial tissue plasminogen activator as well as mechanical approaches to restoring perfusion in this critical area of the brain.

Diagnostic and Prognostic Impact of pc-ASPECTS Applied to Perfusion CT in the Basilar Artery International Cooperation Study

BACKGROUND AND PURPOSE

The posterior circulation Acute Stroke Prognosis Early CT Score (pc-APECTS) applied to CT angiography source images (CTA-SI) predicts the functional outcome of patients in the Basilar Artery International Cooperation Study (BASICS). We assessed the diagnostic and prognostic impact of pc-ASPECTS applied to perfusion CT (CTP) in the BASICS registry population.

METHODS

We applied pc-ASPECTS to CTA-SI and cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT) parameter maps of BASICS patients with CTA and CTP studies performed. Hypoattenuation on CTA-SI, relative reduction in CBV or CBF, or relative increase in MTT were rated as abnormal.

RESULTS

CTA and CTP were available in 27/592 BASICS patients (4.6%). The proportion of patients with any perfusion abnormality was highest for MTT (93%; 95% confidence interval [CI], 76%-99%), compared with 78% (58%-91%) for CTA-SI and CBF, and 46% (27%-67%) for CBV (P < .001). All 3 patients with a CBV pc-ASPECTS < 8 compared to 6/23 patients with a CBV pc-ASPECTS ≥ 8 had died at 1 month (RR 3.8; 95% CI, 1.9-7.6).

CONCLUSION

CTP was performed in a minority of the BASICS registry population. Perfusion disturbances in the posterior circulation were most pronounced on MTT parameter maps. CBV pc-ASPECTS < 8 may indicate patients with high case fatality.

Hyperintense basilar artery on FLAIR MR imaging: diagnostic accuracy and clinical impact in patients with acute brain stem stroke

BACKGROUND AND PURPOSE

FLAIR-hyperintense vessels are known to be a sign of sluggish collateral blood flow in hemispheric vessel occlusion. Additionally, they seem to have a prognostic implication. The aim of the current study was to evaluate the hyperintense configuration of the basilar artery (FLAIR-hyperintense basilar artery) as a marker of basilar artery occlusion and as a predictor of patient outcome.

MATERIALS AND METHODS

We retrospectively identified 20 patients with basilar artery occlusion who initially underwent MR imaging with subsequent DSA. The diagnostic accuracy of the FLAIR-hyperintense basilar artery sign was tested by 4 independent readers in a case-control design, and the relation among FLAIR-hyperintense basilar artery and DWI posterior circulation-ASPECTS, patient outcome, and patient survival was evaluated. To grade the extent of the FLAIR-hyperintense basilar artery sign, we generated a score by counting the number of sections from the basilar tip to the foramen magnum in which a hyperintense signal in the vessel lumen was present multiplied by the section thickness.

RESULTS

The FLAIR-hyperintense basilar artery sign showed moderate sensitivity (65%-95%) but very good specificity (95%-100%) and accuracy (85%-93%) for the detection of basilar artery occlusion. Substantial or excellent inter-reader agreement was observed (Cohen κ, 0.64-0.85). The FLAIR-hyperintense basilar artery inversely correlated with the posterior circulation-ASPECTS (r = -0.67, P = .01). Higher FLAIR-hyperintense basilar artery scores were associated with patient death (28.3 ± 13.7 versus 13.4 ± 11.1, P < .05).

CONCLUSIONS

The FLAIR-hyperintense basilar artery sign proved to be a valuable marker of vessel occlusion and may substantially support the diagnosis of basilar artery occlusion. The established FLAIR-hyperintense basilar artery score may be helpful for the prediction of individual patient survival.

Childhood basilar artery occlusion: a report of 5 cases and review of the literature

Basilar artery occlusion has poor outcome in adults; little is known regarding outcomes in children. Whether intra-arterial treatments improve adult outcomes is controversial. Safety and efficacy of intra-arterial treatments in children are unknown. We report 5 cases of basilar artery occlusion and review published cases. We estimated National Institute of Health Stroke Scale (NIHSS) and modified Rankin Score (mRS) of published cases, compared scores between non-intra-arterial treatments and intra-arterial treatments groups, and examined the correlation between NIHSS and mRS. Of our cases, 4 had good outcomes and 1 died. Of 63 published cases, 45 had no intra-arterial treatments and 18 had intra-arterial treatments. In the non-intra-arterial treatments group 24 had good outcomes. In the intra-arterial treatments group 13 had good outcomes. There was strong correlation between the NIHSS and the mRS. Children with basilar artery occlusion have better outcomes than adults. Certain children with basilar artery occlusion may be treated conservatively. A registry for childhood basilar artery occlusion is urgently needed.