Endovascular Thrombectomy Versus Intravenous Alteplase For Distal Medium Vessel Occlusions: A Propensity Score-Matched Analysis.

Background: The benefits of endovascular thrombectomy (EVT) for distal medium vessel occlusions (DMVOs) are not well established. This study aimed to determine the superiority of EVT over intravenous tissue-type plasminogen activator (IV tPA) in the treatment of DMVOs. Methods: This study analyzed data from the Kanagawa Intravenous and Endovascular Treatment of Acute Ischemic Stroke Registry, a prospective, multicenter, observational registry of acute ischemic stroke patients treated with EVT or IV tPA. The study evaluated patients with acute DMVOs who were treated with EVT and/or IV tPA. DMVOs was defined as occlusions in M2-M3 segment of the middle cerebral artery, anterior cerebral artery, or posterior cerebral artery. The analysis included primary DMVOs and excluded secondary DMVOs, such as distal embolism after recanalization of proximal vessel occlusion. Propensity score-matched analysis was conducted to compare the outcomes between EVT and IV tPA alone. A good outcome was defined as a modified Rankin Scale score 0-2 or no worsening at 90 days. An excellent outcome was defined as an modified Rankin Scale score 0-1. Results: The study included 1148 patients with DMVOs, of whom 816 were treated with EVT and 332 were IV tPA alone. Before propensity score matching, the incidence of good and excellent outcomes was significantly lower in EVT group (good outcomes: EVT 50.3% versus IV tPA 68.0%; P < 0.01; excellent outcomes: 39.8% versus 59.8%; P < 0.001). After propensity score matching, there were no significant differences between EVT and IV tPA groups in good outcomes (EVT 57.8% versus IV tPA 61.3%; P = 0.51), excellent outcomes (46.6% versus 55.0%; P = 0.17), all cerebral hemorrhage (11.6% versus 12.7%; P = 0.74), and symptomatic hemorrhage (2.9% versus 0.6%; P = 0.13). Subarachnoid hemorrhage was more frequent in EVT group (14.5% versus IV tPA 0%). Conclusion: The benefits of EVT for acute DMVOs were similar to IV tPA alone. Randomized multicenter trials are warranted to establish the superiority of EVT over IV tPA alone for DMVOs.