Basilar Artery International Cooperation Study Research Articles

Aspiration Versus Stent Retriever Thrombectomy in Basilar‐Artery Occlusion; Results From the BASICS Trial

Background Both aspiration and stent retriever thrombectomy are safe and effective in patients with acute ischemic stroke due to large vessel occlusion in the anterior circulation. Little is known on the outcomes of these techniques in patients with basilar artery occlusion. This study aimed to compare clinical, technical, and safety outcomes of aspiration and stent retriever thrombectomy as first‐line treatment for basilar artery occlusion in the BASICS (Basilar artery International Cooperation Study) trial. Methods For this post hoc analysis of the BASICS trial, all patients with a basilar artery occlusion who received endovascular treatment with either direct aspiration or stent retriever thrombectomy as first‐line approach were included. When both techniques were registered as first choice, patients were considered to have been treated with stent retriever. The primary outcome was favorable functional outcome, defined as a modified Rankin scale score of 0–3 at 90 days follow‐up, and analyzed using binary logistic regression analysis. Secondary outcomes included the modified Rankin scale score at 90 days (ranging from 0 to 6), procedure duration, mortality at 90 days, and symptomatic intracranial hemorrhage. Secondary outcomes were analyzed using binary, linear, or ordinal regression analyses. All analyses were adjusted for predefined variables. Results Among 158 BASICS patients treated with endovascular treatment,127 were treated with either stent retriever (N=67, 53%), or aspiration (N=60, 47%) as the first‐line treatment modality. We observed no significant difference in favorable functional outcome between patients treated with aspiration and stent retriever thrombectomy as first modality (adjusted odds ratio, 1.80; [95% CI, 0.68–4.76]). Also modified Rankin scale score at 90 days (adjusted common odds ratio, 0.62; [95% CI, 0.30–1.27]) and incidence of symptomatic intracranial hemorrhage (adjusted odds ratio, 0.61; [95% CI, 0.08–4.76]) showed no significant differences between both techniques. Procedure time was shorter with a median of 32 versus 47 minutes (26%; 95% CI, −42 to −6) and mortality rates at 90 days were lower (adjusted odds ratio, 0.36; [95% CI: 0.13–1.00]) in the direct aspiration group. Conclusions This study shows no difference in favorable functional outcome in patients with a basilar artery occlusion treated with direct aspiration compared with patients treated with stent retriever thrombectomy within the BASICS trial, despite a shorter procedure time and lower mortality rate at 90 days.

Therapeutic strategies for acute basilar-artery occlusion

Therapeutic strategies for acute basilar-artery occlusion

Endovascular Therapy for Basilar Artery Occlusion.

Basilar artery occlusion is one of the most devastating neurological conditions with high risks of disability and mortality. Despite the overwhelming benefit of endovascular therapy (EVT) in the anterior circulation and observational data supporting the efficacy of EVT in the posterior circulation, evidence from randomized controlled trials in basilar artery occlusion had been lacking until recently. The BEST (Basilar Artery Occlusion Endovascular Intervention Versus Standard Medical Treatment) and BASICS (Basilar Artery International Cooperation Study) randomized trials showed a nonsignificant direction of benefit but failed to demonstrate the superiority of EVT over standard medical therapy in basilar artery occlusion. However, these trials paved the way for 2 subsequent positive trials by highlighting the importance of consecutive recruitment, fast enrollment and avoidance or minimization of cross-over. The recently completed ATTENTION (Endovascular Treatment for Acute Basilar Artery Occlusion) and BAOCHE (Basilar Artery Occlusion Chinese Endovascular Trial) trials showed that EVT is beneficial for basilar artery occlusion within 24 hours of onset, with a treatment effect similar to what has been shown in anterior circulation large vessel occlusion ischemic stroke. In this topical review, we examine and contextualize the current evidence on EVT for basilar artery occlusion.

Endovascular Therapy for Basilar Artery Occlusion: Among the First to Conceptualize, Last to Prove.

In 1981, the dismal outcomes of patients with basilar artery occlusion (BAO) inspired the first reports of intra-arterial thrombolytic treatment in BAO. These reports were among the first to conceptualize that opening an artery could help patients with large vessel occlusion stroke. Whereas multiple anterior circulation LVO trials demonstrated the efficacy of endovascular therapy starting in 2014, proof of benefit for BAO was lacking until 2022. In this commentary, we reflect on how the BASICS (Basilar Artery International Cooperation Study) and BEST (Basilar Artery Occlusion: Endovascular Interventions vs Standard Medical Treatment) trials lay the foundations for clinical trials in BAO, subsequently leading to the positive results of the ATTENTION (Endovascular Treatment for Acute Basilar-Artery Occlusion) and BAOCHE (Basilar Artery Occlusion Chinese Endovascular) trials.

Current Opinions on Optimal Management of Basilar Artery Occlusion: After the BEST of BASICS Survey

Background The best management of basilar artery occlusion (BAO) remains uncertain. The BASICS (Basilar Artery International Cooperation Study) and the BEST (Basilar Artery Occlusion Endovascular Intervention Versus Standard Medical Treatment) trials reported neutral results. We sought to understand physicians’ approaches to BAOs and whether further BAO randomized controlled trials were warranted. Methods We conducted an online international survey from January to March 2022 to stroke neurologists and neurointerventionalists. Survey questions were designed to examine clinical and imaging parameters under which clinicians would offer (or rescind) a patient with BAO to endovascular therapy (EVT) or best medical management versus enrollment into a randomized clinical trial. Results Of >3002 invited participants, 1245 responded (41.4% response rate) from 73 countries, including 54.7% stroke neurologists and 43.6% neurointerventionalists. More than 95% of respondents would offer EVT to patients with BAO, albeit in various clinical circumstances. There were 70.0% of respondents who indicated that the BASICS and BEST trials did not change their practice. Only 22.1% of respondents would perform EVT according to anterior circulation occlusion criteria. The selection of patients for BAO EVT by clinical severity, timing, and imaging modality differed according to geography, specialty, and country income level. Over 80% of respondents agreed that further randomized clinical trials for BAO were warranted. Moreover, 45.6% of respondents indicated they would find it acceptable to enroll all trial‐eligible patients into the medical arm of a BAO trial, whereas 26.3% would not enroll. Conclusion Most stroke physicians continue to believe in the efficacy of EVT in selected patients with BAO in spite of BEST and BASICS. There is no consensus on which selection criteria to use, and few clinicians would use anterior circulation occlusion criteria for BAOs. Further randomized clinical trials for BAO are warranted.

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.

Predictors of unfavorable outcome at 90 days in basilar artery occlusion patients.

BACKGROUNDIn a previous study, basilar artery occlusion (BAO) was shown to lead to death or disability in 80% of the patients. The treatment for BAO patients in the acute stage includes thrombolysis and intra-arterial thrombectomy, but not all patients benefit from these treatments. Thus, understanding the predictors of outcome before initiating these treatments is of special interest.AIMTo determine the predictors related to the 90-d clinical outcome in patients with BAO in an Asian population. METHODSWe performed a retrospective case review of patients admitted to a tertiary stroke center between 2015 and 2019. We used the international classification of diseases-10 criteria to identify cases of posterior circulation stroke. A neurologist reviewed every case, and patients fulfilling the criteria defined in the Basilar Artery International Cooperation Study were included. We then analyzed the patients’ characteristics and factors related to the 90-d outcome. RESULTSWe identified a total of 99 patients as real BAO cases. Of these patients, 33 (33.3%) had a favorable outcome at 90 d (modified Rankin Scale: 0–3). Moreover, 72 patients received intra-arterial thrombectomy, while 13 patients received intravenous tissue-type plasminogen activator treatment. We observed a favorable outcome in 33.3% of the cases and an unfavorable outcome in 66.7% of the cases. We found that the initial National Institutes of Health Stroke Scale (NIHSS) score and several BAO symptoms, including impaired consciousness, tetraparesis, and pupillary abnormalities, were significantly associated with an unfavorable outcome (P < 0.05), while cerebellar symptoms were associated with a favorable outcome (P < 0.05). In the receiver operating characteristic (ROC) analysis, the areas under the ROC curve of initial NIHSS score, impaired consciousness, tetraparesis, cerebellar symptoms, and pupillary abnormalities were 0.836, 0.644, 0.727, 0.614, and 0.614, respectively. Initial NIHSS score showed a higher AUROC (0.836) compared to BAO symptoms.CONCLUSIONThe most important predictor of an unfavorable outcome was the initial NIHSS score. BAO symptoms, including tetraparesis, impaired consciousness, and pupillary abnormality were also related to an unfavorable outcome.

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 (ORBEST: 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 (ORBEST: 1.687, 95% CI: 1.077–2.644; ORBASIC: 1.653, 95% CI: 1.038–2.631) and favorable outcome (ORBEST: 2.280, 95% CI: 1.484–3.502; ORBASIC: 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.

Advances in Stroke: Treatments-Interventional.

Advances in Stroke: Treatments-Interventional.

Endovascular Treatment for Posterior Circulation Stroke in Routine Clinical Practice: Results of the Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands Registry.

The benefit of endovascular treatment (EVT) for posterior circulation stroke (PCS) remains uncertain, and little is known on treatment outcomes in clinical practice. This study evaluates outcomes of a large PCS cohort treated with EVT in clinical practice. Simultaneous to this observational study, several intervention centers participated in the BASICS trial (Basilar Artery International Cooperation Study), which tested the efficacy of EVT for basilar artery occlusion in a randomized setting. We additionally compared characteristics and outcomes of patients treated outside BASICS in trial centers to those from nontrial centers. We included patients with PCS from the Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands Registry: a prospective, multicenter, observational study of patients who underwent EVT in the Netherlands between 2014 and 2018. Primary outcome was a score of 0 to 3 on the modified Rankin Scale at 90 days. Secondary outcomes included reperfusion status and symptomatic intracranial hemorrhage. For outcome comparison between patients treated in trial versus nontrial centers, we used ordinal logistic regression analysis. We included 264 patients of whom 135 (51%) had received intravenous thrombolysis. The basilar artery was most often involved (77%). Favorable outcome (modified Rankin Scale score 0-3) was observed in 115/252 (46%) patients, and 109/252 (43%) patients died. Successful reperfusion was achieved in 178/238 (75%), and symptomatic intracranial hemorrhage occurred in 9/264 (3%). The 154 nontrial patients receiving EVT in BASICS trial centers had similar characteristics and outcomes as the 110 patients treated in nontrial centers (modified Rankin Scale adjusted cOR: 0.77 [95% CI, 0.5-1.2]). Our study shows that high rates of favorable clinical outcome and successful reperfusion can be achieved with EVT for PCS, despite high mortality. Characteristics and outcomes of patients treated in trial versus nontrial centers were similar indicating that our cohort is representative of clinical practice in the Netherlands. Randomized studies using modern treatment approaches are needed for further insight in the benefit of EVT for PCS.

Endovascular Therapy for Stroke due to Basilar Artery Occlusion: A BASIC Challenge at BEST.

Basilar artery occlusion stroke is known to have poor outcome with a high rate of morbidity and mortality despite best medical therapy. Since the original report of intra-arterial therapy for basilar artery occlusion in 1983, two recent randomized trials comparing endovascular therapy versus best medical management were completed on a large scale, BASICS (Basilar Artery International Cooperation Study) and the BEST trial (Basilar Artery Occlusion Endovascular Intervention Versus Standard Medical Treatment), both of which demonstrated equivocal benefit of the two modalities. In this commentary, we comment and highlight important lessons related to basilar occlusion stroke as learned from the BASICS and BEST randomized trials.

Response to Late-Window Endovascular Revascularization Is Associated With Collateral Status in Basilar Artery Occlusion.

Background and Purpose- The benefit of endovascular therapy in extended time windows has been demonstrated in patients with anterior circulation large vessel occlusion ischemic stroke and favorable imaging profile. We evaluated whether collaterals and thrombus burden influence the associations between revascularization, time-to-treatment, and outcome in endovascular therapy-treated patients with basilar artery occlusion. Methods- We retrospectively analyzed clinical and imaging data of consecutive endovascular therapy-treated patients with basilar artery occlusion included in the multicenter Basilar Artery Treatment and Management Collaboration. The BATMAN (Basilar Artery on Computed Tomography Angiography score, which evaluates thrombus burden and collaterals) and the PC-CS (Posterior Circulation Collateral score, which evaluates collaterals) were assessed on computed tomography angiography, blinded to clinical outcome. Good outcome was defined as modified Rankin Scale score of ≤3 within 3 months; revascularization (successful reperfusion) as modified Thrombolysis in Cerebral Infarction 2b-3 (or TIMI [Thrombolysis in Myocardial Infarction] 2-3 in the BASICS [Basilar Artery International Cooperation Study] registry). Results- We included 172 patients with basilar artery occlusion treated with endovascular therapy (124 with mechanical thrombectomy): mean (SD) age 65 (13) years, median National Institutes of Health Stroke Scale 22 (interquartile range 12-30), 64 (37%) treated >6 hours. Revascularization (achieved in 79% of patients) was associated with good outcome (P=0.003). The use of new generation thrombectomy devices was associated with good outcome (P=0.03). In patients who achieved revascularization, 29/46 (63%) of patients with a favorable BATMAN score and 26/51 (51%) with favorable PC-CS had good outcomes. In logistic regression analysis (adjusted for age, National Institutes of Health Stroke Scale, and time-to-treatment ≤6/>6 hours), revascularization was associated with good outcome in patients with favorable BATMAN score (odds ratio, 15.8; 95% CI, 1.4-175; P=0.02) or PC-CS (odds ratio, 9.4; 95% CI, 1.4-64; P=0.02). In patients who achieved revascularization, early (time-to-treatment ≤6 hours) but not late treatment was associated with improved outcome in patients with unfavorable BATMAN score (18/52 [35%]; odds ratio, 15; 95% CI, 1.9-124; P=0.01) or PC-CS (16/44 [36%]; odds ratio, 5.5; 95% CI, 1.4-21; P=0.01). Conclusions- Revascularization is associated with good outcome in patients with basilar artery occlusion with good collaterals and less extensive occlusion, even >6 hours after onset.

Clot length predicts recanalisation but not outcome after basilar artery occlusion.

The aim of our study was to evaluate the effect of clot length on both recanalisation and outcome in acute basilar artery occlusion (BAO). One hundred forty-nine patients with an acute basilar artery occlusion from the Basilar Artery International Cooperation Study (BASICS) were included. Clot length was assessed on computed tomographic angiography. Thrombus length was divided in tertiles and was related to recanalisation and outcome at 1 month, with Poisson regression. Modified Rankin scale scores of 4 or 5, or death were considered poor outcomes. Additionally, clot length was analysed as a continuous variable. Forty-nine patients (33%) had a short (4-11 mm), 50 (34%) an intermediate (12-22 mm), and 50 (34%) a long clot (≥23 mm). Multivariable analyses showed a significantly lower probability of recanalisation but no statistically significant difference in poor outcome for patients with a long clot compared with patients with a short clot (RR 0.64, 95% CI: 0.42-0.98 and RR 1.10, 95% CI: 0.88-1.37, respectively). No statistically significant differences were found for patients with an intermediate clot length compared with patients with a short clot length (RR 0.97, 95% CI: 0.75-1.25 and RR 1.11, 95% CI: 0.88-1.40, respectively). Analyses of clot length as a continuous variable showed a 10% reduction in chance of recanalisation and a 2% increase in risk of poor outcome with every centimeter increase in clot length (RR 0.90, 95% CI: 0.78-1.04 and RR 1.02, 95% CI: 0.98-1.05, respectively). Clot length predicted recanalisation but not outcome at 1 month in patients with a BAO. We found 2% more poor outcome and 10% less recanalisation with every centimeter increase in clot length.

CT-angiography source images indicate less fatal outcome despite coma of patients in the Basilar Artery International Cooperation Study.

Background Coma is associated with poor outcome in patients with basilar artery occlusion. Aims We sought to assess whether the posterior circulation Acute Stroke Prognosis Early CT Score and the Pons-Midbrain Index applied to CT angiography source images predict the outcome of comatose patients in the Basilar Artery International Cooperation Study. Methods Basilar Artery International Cooperation Study was a prospective, observational registry of patients with acute basilar artery occlusion with 48 recruiting centers worldwide. We applied posterior circulation Acute Stroke Prognosis Early CT Score and Pons-Midbrain Index to CT angiography source images of Basilar Artery International Cooperation Study patients who presented with coma. We calculated adjusted risk ratios to assess the association of dichotomized posterior circulation Acute Stroke Prognosis Early CT Score (≥8 vs. <8) and Pons-Midbrain Index (<3 vs. ≥3) with mortality and favourable outcome (modified Rankin Scale score 0-3) at one month. Results Of 619 patients in the Basilar Artery International Cooperation Study registry, CT angiography source images were available for review in 158 patients. Among these, 78 patients (49%) presented with coma. Compared to non-comatose patients, comatose patients were more likely to die (risk ratios 2.34; CI 95% 1.56-3.52) and less likely to have a favourable outcome (risk ratios 0.44; CI 95% 0.24-0.80). Among comatose patients, a Pons-Midbrain Index < 3 was related to reduced mortality (adjusted RR 0.66; 95% CI 0.46-0.96), but not to favourable outcome (adjusted RR 1.19; 95% CI 0.39-3.62). Posterior circulation Acute Stroke Prognosis Early CT Score dichotomized at ≥ 8 vs. <8 was not significantly associated with death (adjusted RR 0.70; 95% CI 0.46-1.05). Conclusion In comatose patients with basilar artery occlusion, the extent of brainstem ischemia appears to be related to mortality but not to favourable outcome.

Neurologic Examination at 24 to 48 Hours Predicts Functional Outcomes in Basilar Artery Occlusion Stroke.

Accurate long-term outcome prognostication in basilar artery occlusion strokes may guide clinical management in the subacute stage. We determine the prognostic value of the follow-up neurological examination using the National Institutes of Health stroke scale (NIHSS) and identify 24- to 48-hour NIHSS risk categories in basilar artery occlusion patients. Participants of an observational registry of radiologically confirmed acute basilar artery occlusion (BASICS [Basilar Artery International Cooperation Study]) with prospectively collected 24- to 48-hour NIHSS and 1-month modified Rankin scale scores were included. Uni- and multivariable modeling were performed to identify independent predictors of poor outcome. Predictive powers of baseline and 24- to 48-hour NIHSS for poor outcome (modified Rankin scale, 4-6) and 1-month mortality were determined by receiver operating characteristic analyses. Classification and regression tree analysis was performed to identify risk groups. Three hundred seventy-six of 619 BASICS participants were included, of whom 65.4% had poor outcome. In multivariable analyses, 24- to 48-hour NIHSS (odds ratio=1.28 [1.21-1.35]), history of minor stroke (odds ratio=2.64 [1.04-6.74], time to treatment >6 hours (odds ratio=3.07 [1.35-6.99]), and age (odds ratio=1.02 [0.99-1.04]) were retained in the final model as predictors of poor outcome. Prognostic power of 24- to 48-hour NIHSS was higher than baseline NIHSS for 1-month poor outcome (area under the curve, 0.92 versus 0.75) and mortality (area under the curve, 0.85 versus 0.72). Classification and regression tree analysis identified five 24- to 48-hour NIHSS risk categories with poor outcome rates of 9.4% (NIHSS 0-4), 36% (NIHSS 5-11), 84.3% (NIHSS 12-22), 96.1% (NIHSS 23-27), and 100% (NIHSS≥28). Twenty-four- to 48-hour NIHSS accurately predicts 1-month poor outcome and mortality and represents a clinically valuable prognostic tool for the care of basilar artery occlusion patients.

Collateral flow predicts outcome after basilar artery occlusion: The posterior circulation collateral score.

Our aim was to assess the prognostic value of a semiquantitative computed tomography angiography-based grading system, for the prediction of outcome in patients with acute basilar artery occlusion, based on the presence of potential collateral pathways on computed tomography angiography: the posterior circulation collateral score (PC-CS). One hundred forty-nine patients with acute basilar artery occlusion from the Basilar Artery International Cooperation Study were included. We related poor outcome at one month, defined as a modified Rankin scale score of 4 or 5, or death to collateral flow with Poisson regression. We used a 10 points grading system to quantify the potential for collateral flow in the posterior communicating arteries and the cerebellar arteries. Additionally, the relation between the presence and size of posterior communicating arteries and outcome was analyzed. Thirty-six patients had poor (PC-CS: 0-3), 59 patients intermediate (PC-CS: 4-5), and 54 patients good (PC-CS: 6-10) collaterals. Multivariable analyses showed a statistically significant lower risk of poor outcome in patients with a good PC-CS than in patients with a poor PC-CS (risk ratio (RR): 0.74, 95% confidence interval (CI): 0.58-0.96), but not for patients with an intermediate PC-CS compared with patients with a poor PC-CS (RR: 0.95, 95% CI: 0.78-1.15). Multivariable analyses showed a statistically significant lower risk of poor outcome for the presence of at least one posterior communicating artery and for larger caliber of posterior communicating arteries (RR: 0.79, 95% CI: 0.66-0.95 and 0.76, 95% CI: 0.61-0.96, respectively). The PC-CS predicted poor outcome at one month. In a separate analysis, both the absence and smaller caliber of posterior communicating arteries predicted poor outcome.

Prodromal Transient Ischemic Attack or Minor Stroke and Outcome in Basilar Artery Occlusion

The presence of prodromal transient ischemic attacks (TIAs) has been associated with a favorable outcome in anterior circulation stroke. We aimed to determine the association between prodromal TIAs or minor stroke and outcomes at 1 month, in the Basilar Artery International Cooperation Study, a registry of patients presenting with an acute symptomatic and radiologically confirmed basilar artery occlusion. A total of 619 patients were enrolled in the registry. Information on prodromal TIAs was available for 517 patients and on prodromal stroke for 487 patients. We calculated risk ratios and corresponding 95% confidence intervals (CIs) for poor clinical outcome (modified Rankin Scale score ≥4) according to the variables of interest. Prodromal minor stroke was associated with poor outcome (crude risk ratio [cRR], 1.26; 95% CI, 1.12-1.42), but TIAs were not (cRR, .93; 95% CI, .79-1.09). These associations remained essentially the same after adjustment for confounding variables. Prodromal minor stroke was associated with an unfavorable outcome in patients with basilar artery occlusion, whereas prodromal TIA was not.

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

We assessed the prevalence of vertebral artery (VA) stenosis or occlusion and its influence on outcome in patients with acute basilar artery occlusion (BAO). We studied 141 patients with acute BAO enrolled in the Basilar Artery International Cooperation Study (BASICS) registry of whom baseline CT angiography (CTA) of the intracranial VAs was available. In 72 patients an additional CTA of the extracranial VAs was available. Adjusted risk ratios (aRRs) for death and poor outcome, defined as a modified Rankin Scale score ≥4, were calculated with Poisson regression in relation to VA occlusion, VA occlusion or stenosis ≥50%, and bilateral VA occlusion. Sixty-six of 141 (47%) patients had uni- or bilateral intracranial VA occlusion or stenosis ≥50%. Of the 72 patients with intra- and extracranial CTA, 46 (64%) had uni- or bilateral VA occlusion or stenosis ≥50% and 9 (12%) had bilateral VA occlusion. Overall, VA occlusion or stenosis ≥50% was not associated with the risk of poor outcome. Patients with intra- and extracranial CTA and bilateral VA occlusion had a higher risk of poor outcome than patients without bilateral VA occlusion (aRR, 1.23; 95% CI 1.02-1.50). The risk of death did not depend on the presence of unilateral or bilateral VA occlusion or stenosis ≥50%. In conclusion, in patients with acute BAO, unilateral VA occlusion or stenosis ≥50% is frequent, but not associated with an increased risk of poor outcome or death. Patients with BAO and bilateral VA occlusion have a slightly increased risk of poor outcome.

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

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. 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. 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). 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.

The Basilar Artery International Cooperation Study (BASICS): study protocol for a randomised controlled trial

BackgroundDespite recent advances in acute stroke treatment, basilar artery occlusion (BAO) is associated with a death or disability rate of close to 70%. Randomised trials have shown the safety and efficacy of intravenous thrombolysis (IVT) given within 4.5 h and have shown promising results of intra-arterial thrombolysis given within 6 h of symptom onset of acute ischaemic stroke, but these results do not directly apply to patients with an acute BAO because only few, if any, of these patients were included in randomised acute stroke trials.Recently the results of the Basilar Artery International Cooperation Study (BASICS), a prospective registry of patients with acute symptomatic BAO challenged the often-held assumption that intra-arterial treatment (IAT) is superior to IVT. Our observations in the BASICS registry underscore that we continue to lack a proven treatment modality for patients with an acute BAO and that current clinical practice varies widely.DesignBASICS is a randomised controlled, multicentre, open label, phase III intervention trial with blinded outcome assessment, investigating the efficacy and safety of additional IAT after IVT in patients with BAO. The trial targets to include 750 patients, aged 18 to 85 years, with CT angiography or MR angiography confirmed BAO treated with IVT. Patients will be randomised between additional IAT followed by optimal medical care versus optimal medical care alone. IVT has to be initiated within 4.5 h from estimated time of BAO and IAT within 6 h. The primary outcome parameter will be favourable outcome at day 90 defined as a modified Rankin Scale score of 0–3.DiscussionThe BASICS registry was observational and has all the limitations of a non-randomised study. As the IAT approach becomes increasingly available and frequently utilised an adequately powered randomised controlled phase III trial investigating the added value of this therapy in patients with an acute symptomatic BAO is needed (clinicaltrials.gov: NCT01717755).