Efficacy and safety of endovascular thrombectomy for large vessel occlusion stroke beyond 24 hours from time last known well: a systematic review and meta-analysis.

Background: Endovascular thrombectomy (EVT) has become the standard of care for selected patients with acute ischemic stroke within 24 hours of symptom onset. However, the efficacy and safety of EVT for stroke presenting beyond 24 hours is undetermined.

Methods: We performed a systematic review and meta-analysis to examine the outcomes of EVT in patients with acute ischemic stroke beyond 24 hours from onset. The primary outcome was 90-day functional independence defined as the modified Rankin Scale score of 0-2 (mRS 0-2). Secondary outcomes included successful reperfusion defined as Thrombolysis in Cerebral Infarction 2b-3 (TICI 2b-3), symptomatic intracranial hemorrhage (sICH), and 90-day mortality.

Results: Six studies enrolled a total of 5,868 patients to compare the prognosis of EVT for stroke patients treated beyond 24 hours versus within 6-24 hours. The study results indicated that there was no difference in the rate of successful reperfusion (RR 1.00, 95% CI 0.94-1.06, P = 0.96) and sICH (RR 0.63, 95% CI 0.35-1.16, P = 0.14) between the two groups of patients who underwent EVT at different times. Four studies involving 707 patients compared the outcomes of EVT versus best medical treatment (BMT), including thrombolysis, for stroke patients treated beyond 24 hours. Compared to patients receiving BMT, those undergoing EVT were more likely to achieve 90-day functional independence (RR 1.96, 95% CI 1.27-3.01, P < 0.05) and a lower risk of sICH (RR 3.52, 95% CI 1.11-11.20, P = 0.03), with no significant difference in 90-day mortality rates (RR 0.86, 95% CI 0.58-1.28, P = 0.46).

Conclusions: Our study found that the EVT time window did not significantly affect TICI 2b-3 and sICH, and EVT showed better therapeutic effects than BMT for stroke patients beyond 24 hours. Specifically, patients who underwent EVT beyond 24 hours had a higher proportion of functional independence at 90 days and a lower risk of sICH. Therefore, EVT remains an effective treatment option for patients with large vessel ischemic stroke beyond the traditional 24-hour time window.