Abstract 1: The Very Core Limit Of Endovascular Therapy For Acute Stroke With A Large Ischemic Region

Background and Purpose: To assess the actual malignant core volume in endovascular therapy (EVT) eligible patients with large ischemic regions from the RESCUE-Japan LIMIT database. Methods: RESCUE-Japan LIMIT was a multicenter, open-label, randomized clinical trial in large vessel occlusion patients with large ischemic region indicated by an ASPECTS valued from 3 to 5. We assessed the volumetrically measured core volume which identifies an unfavorable outcome (modified Rankin Scale; mRS 4-6 at 90 days) by receiver operating characteristic (ROC) analysis in the endovascular therapy (EVT) group. Predictive marginal probabilities were also assessed to identify the unfavorable outcome. Symptomatic intracranial hemorrhages and death within 90 days in the EVT group and the medical management (MM) group were compared. Clinical characteristics and radiological values were also compared. Results: Of the 203 cases enrolled, 182 patients (92 in EVT group vs. 90 in MM group) had adequate core volume. The mean age was 75.6±10 years old and 46% of females in the EVT group and 77.0±10 years old and 42% of females in the MM group. Median core volume was 94 (IQR; 65.3-147.5) mL in EVT patients and 110 (IQR; 74.0-140.0) mL in those with MM group (P=0.84). ROC analysis identified a core volume of 120 mL as the unfavorable outcome (61/92) in the EVT group (51% sensitivity and 77% specificity, area under curve=0.65) and 99 mL in the MM group (77/91, 62% sensitivity and 54% specificity, area under curve=0.56). Predictive marginal probabilities indicated 132 mL as an overlay of the two groups for achieving the unfavorable functional outcome. Symptomatic intracranial hemorrhage was seen in 9.8% in the EVT group and 5.6% in the MM group (p=0.28), and death within 90 days was 17.4% in the EVT group and 23.3% in the MM group (p=0.32). Conclusions: The current analysis demonstrates that a core threshold of approximately 130 mL is the upper limit for identifying large ischemic region stroke patients treated with EVT who are unlikely to suffer from unfavorable outcomes. EVT-eligible patients under this threshold may benefit from EVT. Registration: URL: http://www.clinicaltrials.gov; Unique identifier: NCT03702413.