Is Intra-Arterial Thrombolysis Beneficial for M2 Occlusions? Subgroup Analysis of the PROACT-II Trial

Background and Purpose— The role of endovascular therapy for acute M2 trunk occlusions is debatable. Through a subgroup analysis of Prolyse in Acute Cerebral Thromboembolism-II, we compared outcomes of M2 occlusions in treatment and control arms. Methods— Solitary M2 occlusions were identified from the Prolyse in Acute Cerebral Thromboembolism-II database. Primary endpoints were successful angiographic reperfusion (TICI 2–3) at 120 minutes and functional independence (mRS 0–2) at 90 days. Results— Forty-four patients with solitary M2 occlusions, 30 in the treatment arm and 14 in the control arm, were identified. Successful reperfusion (TICI 2–3) was achieved in 53.6% and 16.7% of patients in the treatment and control arms, respectively (P=0.04). A favorable clinical outcome (mRS 0–2) was observed in 53.3% and 28.6%, respectively (P=0.19). Baseline characteristics were similar between the 2 groups. Conclusions— Intra-arterial thrombolysis may lead to a 3-fold increase in the rate of early reperfusion of solitary M2 occlusions and could potentially double the chance of a favorable functional outcome at 90 days. Clinical Trial Registration— This trial was not registered because enrollment began before July 1, 2005.