Intra-Arterial Thrombolytic vs. Mechanical Thrombectomy in Distal Medium Middle Cerebral Artery Acute Ischemic Stroke: A Preliminary Multinational Multicenter Propensity Score-Matched Study

Background: Optimal treatment for acute ischemic stroke due to distal medium-vessel occlusion (DMVO) in the middle cerebral artery (MCA) remains uncertain. While mechanical thrombectomy (MT) may pose higher risks in DMVO, intra-arterial thrombolysis (IAT)—with or without intravenous thrombolysis (IVT)—could be a safer alternative. Purpose: To compare functional outcomes and safety profiles of IAT versus MT in acute ischemic stroke caused by MCA DMVO (M2–M4 segments). Methods: We performed a retrospective, propensity score-matched study across 37 centers (Asia, Europe, North America) using the MAD-MT registry. Patients with MCA DMVO (M2–M4) treated with IAT or MT (with/without IVT) were included. Propensity score matching adjusted for confounders. The primary outcome was excellent functional outcome (modified Rankin Scale [mRS] 0–1 at 90 days). Results: After matching, 184 patients were analyzed (19 IAT, 165 MT). Baseline characteristics were balanced. At 90 days, excellent functional outcomes occurred in 38% (IAT) versus 21% (MT) (P = 0.20). Functional independence (mRS 0–2) rates were 50% (IAT) versus 40% (MT) (P = 0.42). Mortality was comparable (13% vs. 17%). Successful reperfusion (modified Thrombolysis in Cerebral Infarction [mTICI] 2b–3) was higher with MT (90% vs. 68%; P = 0.02), but symptomatic intracranial hemorrhage occurred only with MT (6.7% vs. 0%; P = 0.60). Conclusion: For MCA DMVO, IAT showed similar functional outcomes and numerically fewer safety events than MT despite lower recanalization rates. These findings should be interpreted cautiously, given the small IAT sample size and require validation in larger prospective studies.