ABSTRACT NUMBER: ESOC2026A593 THE TRADE-OFF BETWEEN TRIAGE PRECISION AND REPERFUSION SPEED: PRE-TRANSFER CTA REDUCES FUTILE TRANSFERS BUT DELAYS TRANSFER EFFICIENCY IN ACUTE ISCHEMIC STROKE

Abstract Background and aims CTA is essential for determining EVT eligibility, but CTA-related workflow delays at PSCs may compromise transfer efficiency for this time-sensitive therapy. Methods We analyzed 316 acute ischemic stroke patients transferred via the Tainan-Chiayi Stroke Network (2021–2025) in Taiwan. Patients were stratified by CTA timing: pre-transfer (PSC-CTA) versus post-transfer (CSC-CTA). Futile transfer was defined as interhospital transfer without subsequent EVT and was further categorized as preventable over-triage (stroke mimics) or medically futile transfer due to spontaneous recanalization or disease progression. Results The PSC-CTA group achieved a significantly higher EVT yield than the CSC-CTA group (73.1% vs. 34.1%; P<0.001). Futility in the CSC-CTA group was mainly due to diagnostic misclassification (stroke mimics or non-LVO), whereas futility in the PSC-CTA group was largely related to interval spontaneous recanalization or subsequent medical ineligibility (large core or chronic occlusion), reflecting appropriate initial triage despite non-treatment. PSC CTA significantly prolonged PSC door-in–door-out times compared with CSC-CTA (139 vs. 88 minutes) but shortened CSC door-to-EVT times (87 vs. 109 minutes). However, the PSC workflow delays still resulted in a nonsignificant trend toward longer total onset-to-EVT times in the PSC-CTA group (median 418 vs. 318 minutes). Favorable functional outcomes at 3 months were numerically higher in the CSC-CTA group (32.5% vs. 28.3%), although not statistically significant. Conclusions While pre-transfer CTA effectively eliminates false-positive transfers, it introduces workflow delays in less-experienced PSCs, potentially prolonging onset-to-EVT time. System-level strategies to optimize PSC workflow performance are therefore needed to better balance triage precision with timely reperfusion. Conflict of interest All authors: nothing to disclose.