Importance: Previous randomized clinical trials (RCTs) have supported the use of endovascular therapy (EVT) in late-window acute ischemic stroke (AIS; 6-24 hours). However, little is known about the use of EVT in very late-window AIS (>24 hours).
Objective: To examine outcomes following EVT for very late-window AIS.
Data sources: A systematic review of the English language literature was conducted using Web of Science, Embase, Scopus, and PubMed to search for articles published from database inception until December 13, 2022.
Study selection: This systematic review and meta-analysis included published studies regarding very late-window AIS treated with EVT. Multiple reviewers screened studies, and an extensive manual search of the references of included articles was performed to identify any missed articles. Of the 1754 initially retrieved studies, 7 published between 2018 and 2023 were ultimately included.
Data extraction and synthesis: Data were extracted independently by multiple authors and evaluated for consensus. Data were pooled using a random-effects model. This study is reported per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guideline, and the protocol was prospectively registered with PROSPERO.
Main outcomes and measures: The primary outcome of interest was functional independence, as assessed with 90-day modified Rankin Scale (mRS) scores (0-2). Secondary outcomes included thrombolysis in cerebral infarction (TICI) scores (2b-3 or 3), symptomatic intracranial hemorrhage (sICH), 90-day mortality, early neurological improvement (ENI), and early neurological deterioration (END). Frequencies and means were pooled with the corresponding 95% CIs.
Results: This review included 7 studies involving a total of 569 patients. The mean baseline National Institutes of Health Stroke Scale score was 13.6 (95% CI, 11.9-15.5), and the mean Alberta Stroke Program Early CT Score was 7.9 (95% CI, 7.2-8.7). The mean time from last known well and/or onset to puncture was 46.2 hours (95% CI, 32.4-65.9 hours). Frequencies for the primary and secondary outcomes were 32.0% (95% CI, 24.7%-40.2%) for functional independence (90-day mRS scores of 0-2) and 81.9% (95% CI, 78.5%-84.9%) for TICI scores of 2b to 3, 45.3% (95% CI, 36.6%-54.4%) for TICI scores of 3, 6.8% (95% CI, 4.3%-10.7%) for sICH, and 27.2% (95% CI, 22.9%-31.9%) for 90-day mortality. In addition, frequencies were 36.9% (95% CI, 26.4%-48.9%) for ENI and 14.3% (95% CI, 7.1%-26.7%) for END.
Conclusions and relevance: In this review, EVT for very late-window AIS was associated with favorable frequencies of 90-day mRS scores of 0 to 2 and TICI scores of 2b to 3 and with low frequencies of 90-day mortality and sICH. These results suggest that EVT may be safe and associated with improved outcomes for very late-window AIS, although RCTs and prospective, comparative studies are needed to determine which patients may benefit from very late intervention.