Abstract 118: Diffusion Lesion Volume Reduction after Recanalization Therapy for Anterior Circulation Stroke with Major Vessel Occlusion: Analysis from the RESCUE-Japan Registry Study

Abstract

Objective: Although Diffusion-weighted imaging (DWI) lesions are commonly irreversible, DWI lesion volume reduction (DVR) is occasionally observed. We investigated clinical significance and predictors of DVR in acute stroke patients with major vessel occlusion receiving recanalization therapy (RT). Methods: The Recovery by Endovascular Salvage for Cerebral Ultra-acute Embolism (RESCUE)-Japan registry prospectively registered 1,442 stroke patients with major vessel occlusion who were admitted to 84 Japanese stroke centers within 24 hours after onset from July 2010 to June 2011. We retrospectively analyzed all patients with the internal carotid artery or middle cerebral artery (M1 or M2 segments occlusions receiving RT and undergoing MRI both on admission and at 24 hours after onset from the registry. We defined DVR as a 1 or more-point reduction of the DWI-Alberta Stroke Program Early CT Score (ASPECTS), and CT-DWI mismatch (CTDM) as a 2 or more-point lower DWI-ASPECTS than CT-ASPECTS on admission. Reperfusion was defined as TICI grade 2b-3 on catheter angiography or modified Mori grade 3 on MRA immediately after RT. Dramatic recovery (DR) was defined as a 10 or more-point reduction or a total NIHSS score of 0-1 at 24 hours, and favorable outcome (FO) defined as a mRS score 0-2 at 3 months. Results: A total of 390 patients (215 men, 72 years old,) was included. Median baseline NIHSS score was 16 (IQR 10-19) and median baseline DWI-ASPECTS was 8 (6-9). CTDM was seen in 92 patients (28%) on admission. Intravenous thrombolysis and endovascular therapy were performed in 246 patients (63%) and 223 patients (57%), respectively. Reperfusion was obtained in 170 patients (51%). DVR was seen in 51 patients (13%). Eighty-eight patients (23%) obtained DR and 158 patients (41%) achieved FO. On multivariate analyses, DVR was significantly related to DR (OR 3.8, 95%CI 1.5-10) and FO (4.6, 1.8-12). CTDM was an independent predictor of DVR (OR 2.5, 95% CI 1.1-5.8). Conclusions: DVR was significantly related to DR and FO. CTDM is a rough predictor of DVR of which area is considered as a “DWI-bright” ischemic penumbra, and might be a useful marker to identify the adequate candidates for RT in spite of relatively large DWI lesions.