Abstract WMP24: Thrombolysis within 48 hours after Basilar Artery Occlusion

Abstract

Introduction: Recanalization therapies and their time window in basilar artery occlusion (BAO) remain empirical and vary among hospitals. Our institutional protocol for BAO does not follow the strict RCT-guided guidelines in hemispheric stroke, and advices thrombolysis up to 12 hours after sudden onset of severe symptoms, and 48 hours after onset of gradually progressing symptoms, provided that extensive infarction changes have not yet occurred. Objective: The aim was to analyse the importance of two fundamental variables, symptom duration and the extent of baseline infarction, on the outcome of thrombolysis-treated BAO. Methods: We prospectively gathered data from 184 consecutive patients with angiography-proven BAO in the Helsinki University Central Hospital, which receives all candidates for stroke thrombolysis in a catchment area of 1.5 million. We took advantage of frequent non-adherence to our management protocol and grouped patients according to "protocol violations" (PVs): exceeded symptom duration (time PV) and large-infarct PV. Patients were divided into 4 categories based on onset-to-treatment time (OTT). Intravenous alteplase (0.9 mg/kg) and concomitant full-dose heparin was administered in the majority of patients. Outcome variables were recanalization of BA, 3-month modified Rankin Scale (mRS) and 1-year mortality. Results: Patients with no PV had the best outcome (when recanalized, 51% had good outcome [mRS 0-2], and 62% were non-dependent [mRS 0-3]), followed by patients with time PV (42% and 58%, respectively). Over 90% of patients with large-infarct PV were dependent, institutionalized, or dead (mRS 4-6), even when recanalized. Compared with 37% in patients with no PV, 1-year mortality was higher in patients with both PVs (68.8%, p<0.05) and large-infarct PV (64.7%, p<0.01); but similar to patients with time PV (45.5%, p=0.61). Importantly, the outcome of recanalized BAO was similar among OTT categories. Conclusions: In the absence of extensive baseline infarct signs, recanalization of BAO up to 48 hours was seldom futile (mRS 4-6) and produced non-dependent outcomes in 60% of patients, which was virtually independent of the exact time window. We recommend a dedicated protocol for BAO in stroke patients screened for thrombolysis.