Abstract TP60: Intravenous Thrombolysis For Patients With Reverse MRA-DWI Mismatch: SAMURAI And NCVC Rt-PA Registries

Abstract

Background and purpose: Characteristics of reverse MRA-DWI mismatch, defined as large DWI lesion despite absence of the major artery occlusion (MAO), remain unknown, especially in patients treated with IV rt-PA. This study aimed to clarify the frequency, associated factors, and outcomes of patients showing reverse MRA-DWI mismatch prior to IV rt-PA therapy. Methods: From the multicenter (SAMURAI) and additional single-center (NCVC) rt-PA registries, patients with the MCA territorial stroke were included. Early ischemic changes (EIC) were assessed with the Alberta Stroke Program Early CT score (ASPECTS) on pretreatment DWI. MAO was defined as ICA or M1 occlusion on MRA. Patients were divided into 4 groups: the large-EIC match (LM) group (MAO, ASPECTS <7); the reverse mismatch (RMM) group (no MAO, ASPECTS <7); the conventional mismatch (CMM) group (MAO, ASPECTS ≧7); and the small-EIC match (SM) group (no MAO, ASPECTS ≧7). Outcomes included sICH per ECASS II criteria, and mRS 0-2 and death at 90 days. Multivariate backward stepwise logistic regression analysis was performed to identify independent clinical characteristics (demographic factors, risk factors, stroke subtypes by TOAST classification, and blood tests) associated with the reverse MRA-DWI mismatch and to compare the outcomes among the 4 groups. Results: Of the 486 patients (167 women, median age 74 years) enrolled, reverse MRA-DWI mismatch was observed in 24 (5%, RMM group); 108 belonged to LM, 161 to CMM, and 193 to SM groups. Among clinical characteristics, cardioembolism (RMM 92%, LM 76%, CM 69%, SM 49%) was only independently associated with the RMM group (OR 5.49, 95%CI 1.25-24.1). Median initial NIHSS score was 18 in RMM, 18 in LM, 13 in CMM, and 8 in SM (p<0.001). MRS 0-2 (RMM 54%, LM 19%, CMM 46%, SM 69%) was more common in the RMM than the LM group (OR 4.02, 95% CI 1.28-12.7). SICH (RMM 13%, LM 6%, CMM 2%, SM 2%) and death (RMM 8%, LM 12%, CMM 9%, SM 2%) were not different between the RMM and LM groups after multivariate analysis. Conclusion: Reverse MRA-DWI mismatch was observed in 5% of patients eligible for rt-PA. Cardioembolism was independently associated with reverse mismatch. Patients with reverse mismatch may benefit from thrombolysis, compared to those with extensive EIC with MAO.