Endovascular Thrombectomy versus Intravenous Alteplase for Distal 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 evaluate whether EVT is superior to intravenous tissue plasminogen activator (IV tPA) alone in DMVOs. Methods This study analyzed data from the K-NET 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 of 0-2 or no worsening at 90 days. An excellent outcome was defined as an mRS score of 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% vs. IV tPA 68.0%, p<0.01; excellent outcomes: 39.8% vs. 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% vs. IV tPA 61.3%, p=0.51), excellent outcomes (46.6% vs. 55.0%, p=0.17), all cerebral hemorrhage (11.6% vs. 12.7%, p=0.74), and symptomatic hemorrhage (2.9% vs. 0.6%, p=0.13). Subarachnoid hemorrhage was more frequent in EVT group (14.5% vs. IV tPA 0%). Conclusions 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. ### Competing Interest Statement Dr T.U. reports consulting fees from Kaneka Medix. Dr. Y.H. reports consulting fees from Bayer Pharmaceutical and Nippon Boehringer Ingelheim. Dr. M.T. reports consulting and lecture fees from Johnson and Johnson and Stryker. ### Clinical Trial NCT05213533 ### Funding Statement The K-NET Registry was partially supported by a grant from the Japanese Society of Neuroendovascular Therapy. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The study protocol of the K-NET registry was approved by the Ethics Committee of St. Marianna University School of Medicine (approval no. 3757). I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes The data supporting the findings of this study are available from the corresponding author upon reasonable request.