Endovascular Thrombectomy versus Medical Management in Patients Presenting Beyond 24 Hours of Last Known Well and With FLAIR Vascular Hyperintensities–DWI Mismatch

BACKGROUND: There is uncertainty regarding the effectiveness of endovascular thrombectomy (EVT) in patients presenting beyond 24 hours. We compared the clinical outcomes of these patients with FVH-DWI mismatch treated with EVT versus best medical management (BMM). METHODS: Consecutive patients meeting eligibility criteria were enrolled from an ongoing, prospective, multicenter TRACK-LVO Late cohort (January 2018 to December 2025). The primary outcome was 90-day functional independence. Safety outcomes included 90-day all-cause mortality, and symptomatic intracranial hemorrhage (sICH). Differences in outcomes were assessed using inverse probability of treatment weighting-adjusted logistic regression models. RESULTS: Among 648 patients screened, 247 met inclusion criteria (median age 63 years [IQR: 55-70]; baseline NIHSS 10 [IQR: 8-13]). Of these, 132 (53%) received EVT and 115 (47%) received BMM. In IPTW-adjusted analyses, the EVT group had significantly higher odds of functional independence (aOR 3.05, 95% CI: 1.69-5.50; P < 0.001) and a favorable shift in mRS scores distribution (aOR: 2.26, 95% CI: 1.41-3.65; P < 0.001) compared to the BMM group. Mortality did not differ significantly between groups (aOR 0.49, 95% CI: 0.15-1.61; P = 0.241). However, EVT was associated with a significantly higher risk of sICH (6.8% vs. 0%; P = 0.012). CONCLUSION: In patients with FVH-DWI mismatch, EVT was associated with better odds of functional independence, despite an increased risk of sICH. These results suggest that the FVH-DWI mismatch may be a useful imaging marker for selecting patients for EVT who present more than 24 hours.