Abstract 199: Maximal Admission Core Lesion Compatible with Favorable Outcome in Acute Stroke Patients Undergoing Endovascular Procedures

Abstract

Infarct volume is a strong predictor of outcome. Multiparametric imaging are meant to identify infarct core or non-reversible lesions, and therefore predict on admission the minimum volume of final infarct even if recanalization is rapidly achieved. We aimed to confirm this hypothesis and define the Maximal Admission Lesion volumes Compatible with favorable OutcoMe (MALCOM) in stroke patients receiving endovascular treatment. Methods: We studied consecutive patients with ICA/MCA occlusion and multiparametric CT/MRI, who underwent endovascular procedures. Indication for procedure was based on ASPECTS>6 and presence of mismatch (visually>20%). Admission infarct core was later measured on initial imaging (CBV-CTP or DWI-MRI) and infarct volume was measured on follow-up CT-scan. Lesion growth was calculated: final lesion–admission core. We defined MALCOM: cut-off admission core volume (CBV or DWI) above which probability of mRS0-2 is <10% Results: 57 patients were studied (29 MRI, 28 CT-perf). For all patients mean core volume was 28±22cc, recanalization TICI2b-3:77%. At 24h mean infarct volume was 64±97cc; mean lesion growth: 37±92cc and at 3 months favorable outcome 45% (mRS 0-2). Infarct growth was larger in non-recanalizers (118±182 Vs 29±77; p=0.04). In patients who recanalized admission core was 29±23cc and final lesion was 57±84cc. Overall the maximal lesion volume compatible with favorable outcome (MALCOM) was 39cc. When recanalization was achieved, up to 62% of patients within MALCOM (<39cc) achieved favorable outcome, whereas despite recanalization only 12% of patients beyond MALCOM (>39cc) achieved mRS0-2 (p=0.01). A regression model adjusted for age and recanalization showed that the only predictor of favorable outcome was having an admission core lesion <MALCOM (OR: 9.3, 95%CI: 1.9-46.4; p<0.01) Analysis according to imaging modality showed that CT-CBV allowed larger MALCOM (42cc) than MR-DWI (29cc). In octogenarians, MALCOM (15cc) was lower than in younger patients (40cc) Conclusion: Admission lesion core is associated with final infarct volume and is a strong predictor of favorable outcome. MALCOM according to imaging modality and patient age could be set and used on admission to select candidates for endovascular procedures.