Reperfusion Therapy in ESCAPE-MeVO Trial Participants: Imaging Characteristics and Clinical Outcomes

Background The randomized ESCAPE-MeVO trial revealed no benefit of endovascular thrombectomy (EVT) plus usual care in participants with acute stroke due to medium-vessel occlusion (MeVO), a heterogeneous patient population. Identifying subgroups most likely to benefit from EVT with the use of baseline imaging remains critical. Purpose To assess the associations of baseline imaging characteristics with clinical outcomes and intravenous thrombolysis (IVT) and EVT effects in participants with MeVO stroke. Materials and Methods In this post hoc analysis of the ESCAPE-MeVO trial (April 2022 to June 2024), head CT, CT angiography (CTA), and CT perfusion baseline imaging characteristics, including occlusion site and collateral status, were assessed in a central blinded core laboratory review. The primary outcome was the 90-day modified Rankin Scale (mRS) score. Outcomes stratified by imaging characteristics were compared between the EVT and control groups. Effect size estimates for associations of imaging features with outcomes were obtained using logistic regression. Multiplicative interaction terms determined whether imaging characteristics modified the effects of IVT or EVT on outcomes. Results A total of 529 ESCAPE-MeVO participants were included (median age, 75 years [IQR, 64-82 years]; 284 male). Most MeVOs (442 of 522 [84.7%]) were in the middle cerebral artery territory. Collateral status at CTA was good in 129 of 517 participants (25.0%), moderate in 276 (53.4%), and poor in 111 (21.5%). Collateral status was the imaging variable associated with the primary outcome in the multivariable analysis (adjusted common odds ratio, 0.82 [95% CI: 0.67, 0.998]). The probability of EVT achieving an adjusted mRS score of 0 or 1 was lower with EVT (25%) in participants with poor collaterals (vs 37% in the control arm) and higher in those with good collaterals (47% in the EVT arm vs 36% in the control arm), although the difference was not statistically significant (P[interaction] = .30). Conclusion Collateral status at CTA may have a weak association with clinical outcomes among patients with MeVO, warranting further investigation. Clinical trial registration no. NCT05151172 © RSNA, 2026 Supplemental material is available for this article. See also the editorial by Bilgin and Kallmes in this issue.