Background and purpose: The management of acute ischemic stroke (AIS) due to distal medium vessel occlusion (DMVO) remains uncertain, particularly in comparing the effectiveness of intravenous thrombolysis (IVT) plus mechanical thrombectomy (MT) versus IVT alone. This study aimed to evaluate the safety and efficacy in DMVO patients treated with either MT-IVT or IVT alone.

Methods: This multinational study analyzed data from 37 centers across North America, Asia, and Europe. Patients with AIS due to DMVO were included, with data collected from September 2017 to July 2023. The primary outcome was functional independence, with secondary outcomes including mortality and safety measures such as types of intracerebral hemorrhage.

Results: The study involved 1,057 patients before matching, and 640 patients post-matching. Functional outcomes at 90 days showed no significant difference between groups in achieving good functional recovery (modified Rankin Scale 0-1 and 0-2), with adjusted odds ratios (OR) of 1.21 (95% confidence interval [CI] 0.81 to 1.79; P=0.35) and 1.00 (95% CI 0.66 to 1.51; P>0.99), respectively. Mortality rates at 90 days were similar between the two groups (OR 0.75, 95% CI 0.44 to 1.29; P=0.30). The incidence of symptomatic intracerebral hemorrhage was comparable, but any type of intracranial hemorrhage was significantly higher in the MT-IVT group (OR 0.43, 95% CI 0.29 to 0.63; P<0.001).

Conclusion: The results of this study indicate that while MT-IVT and IVT alone show similar functional and mortality outcomes in DMVO patients, MT-IVT presents a higher risk of hemorrhagic complications, thus MT-IVT may not routinely offer additional benefits over IVT alone for all DMVO stroke patients. Further prospective randomized trials are needed to identify patient subgroups most likely to benefit from MT-IVT treatment in DMVO.