Abstract 2: French Acute Cerebral Multimodal Imaging to Select Patients for Mechanical Thrombectomy Final Results

Introduction: Target mismatch (TMM) identifies salvageable penumbra independent of time from stroke onset. Current guidelines do not recommend advanced imaging to select patients for mechanical thrombectomy (MT) within 6 hours after onset but indicate that more research is needed. To address this question, we designed a prospective multicenter cohort study to compare the rate of functional neurological recovery (mRS ≤2 @ 3 months) in patients treated by MT for ICA/M1/M2 occlusions within 6 hours after onset according to the presence of a TMM on baseline imaging. Hypothesis: 60% of patients with TMM vs. 35% of no TMM, would achieve an mRS≤2 at 3 months. Sample size calculation: 200 patients. Methods: Consecutive patients eligible for MT within 6 hrs after onset, who underwent CTP or DWI/PWI imaging before treatment were enrolled. No NIHSS or ASPECTS restrictions were applied. Treating teams were blinded of CTP/DWI/PWI maps. mRS at 3 months was rated by an investigator blinded to clinical/imaging/treatment information. Automatically processed maps by RAPID software were reviewed after the end of follow-up. TMM definition followed EXTEND-IA criteria: MM volume >10mL, MM ratio>1.2, Core volume 1.2 and MM volume>10 mL. Imaging-based subgroups (TMM vs. No TMM) were defined after the end of follow-up. Results: 218 patients were enrolled. Baseline imaging profile distribution was 71% TMM, 29% no TMM, (in the no TMM group, 76% had a core volume > 70 mL); 82% MM and 18% no MM. Reperfusion(TICI 2B-3) was achieved in 86% of the patients after a median delay of 4.4 hrs (95%CI 3.6-5.9). 61% of the patients in the TMM group vs. 35% in the no TMM group had an mRS ≤2 @ 3 months, p Conclusion: Patients with salvageable penumbra on advanced imaging experienced a larger benefit from MT than those without. Patients with no penumbra did not appear to benefit from reperfusion.