Outcomes of Intravenous Thrombolysis in Posterior Versus Anterior Circulation Stroke

Background and Purpose-Intravenous thrombolysis is an approved treatment for anterior (ACS) and posterior (PCS) circulation stroke. However, no randomized controlled trial has investigated safety and efficacy of intravenous thrombolysis according to stroke territory, although PCS is assumed to differ from ACS in many ways. We aimed to compare the safety and clinical outcome of intravenous thrombolysis applied to patients with PCS and ACS. Methods-Prospectively collected data of 883 consecutive patients with acute ischemic stroke (788 ACS, 95 PCS) treated with intravenous thrombolysis in 3 Swiss stroke centers were analyzed. Presenting characteristics, symptomatic intracranial hemorrhage, mortality, and favorable outcome (modified Rankin scale 0 or 1) at 3 months were compared between patients with PCS and ACS. Results-As compared with patients with ACS, those with PCS were younger (mean age, 63 versus 67 years, P=0.012) and had a lower mean baseline National Institutes of Health Stroke Scale score (9 versus 12, P<0.001). Patients with PCS less often had symptomatic intracranial hemorrhage (0% versus 5%, P=0.026) and had more often a favorable outcome (66% versus 47%, P<0.001). Mortality was similar in the 2 groups (PCS, 9%; ACS, 13%; P=0.243). After multivariable adjustment, PCS was an independent predictor of lower symptomatic intracranial hemorrhage frequency (P=0.001), whereas stroke territory was not associated either with favorable outcome (P=0.177) or with mortality (P=0.251). Conclusions-Our study suggests that PCS is associated with a lower risk of symptomatic intracranial hemorrhage after intravenous thrombolysis as compared with ACS, whereas favorable outcome and mortality were similar in the 2 stroke territories. (Stroke. 2011;42:2498-2502.)