Abstract 113: Late Window Transfer Patients had Favorable Outcomes Following Thrombectomy in DEFUSE 3

Abstract

Background: Although the treatment benefit of endovascular thrombectomy (EVT) was maintained in transfer patients in the early window trials, overall rates of functional independence were lower in both the EVT and control groups among transfer patients. We hypothesized that the imaging-based selection criteria employed in DEFUSE 3 would lead to comparable outcome rates and treatment efficacy in transfer vs. direct admission patients. Methods: DEFUSE 3 patients were stratified based on if they presented directly to the study site or were transferred from a primary center. The primary and secondary efficacy and safety outcomes of DEFUSE 3 were compared. Results: Of 182 patients randomized, 121 (66%) were transfers and 61 (34%) direct. The 2 groups had similar baseline characteristics, other than transfers had 30 min longer median times from last known well time to arrival at the study site. The primary efficacy outcome (mRS shift at day 90) did not differ in the direct vs. transfer groups, OR 2.9, 95% CI 1.2-7.2, P=0.014 for direct and OR=2.6, 95% CI 1.3-4.8, P=0.009 for transfer (Fig 1). The overall rate of functional independence (mRS 0-2 at day 90) in the EVT group did not differ (44% direct, 45% transfer) nor did the treatment effect: RR 2.0 (0.9-4.4) direct vs. 3.1 (1.6-6.1) for transfer. EVT reperfusion rates were identical (mTICI≥2b 76%) in both groups. The rates of death and SICH did not differ. Transfer patients had more favorable collateral profiles (based on the hypoperfusion intensity ratio) median (IQR) for transfer 0.35 (0.18-0.47) vs. 0.42 (0.25-0.56) for direct, p=0.050. Conclusions: In late window patients selected by penumbral mismatch criteria, both the favorable outcome rates and treatment effects did not decline in transfer patients. These results have healthcare implications indicating transferring potential candidates for late window thrombectomy to EVT centers is associated with substantial clinical benefits and should be strongly encouraged.