Abstract TP174: Onset-to-Door Efficiency Index is Associated With Favorable Outcomes After Endovascular Therapy in Acute Ischemic Stroke

Introduction: In patients with acute ischemic stroke (AIS) requiring endovascular treatment (EVT), onset-to-door time (ODT) is an important prognostic factor, but the impact of transport distance remains unclear. Some studies have emphasized the importance of pre-hospital efficiency. This study examined whether transport distance and hospital arrival efficiency were associated with clinical outcomes, especially prognosis, in EVT patients. As a secondary analysis, we also investigated social factors related to hospital arrival efficiency. Methods: We retrospectively screened consecutive AIS patients eligible for EVT between May 2014 and May 2025. Transport distance was defined as the straight-line distance from the centroid of the patient’s home postal code to our hospital. As an index of hospital arrival efficiency, we calculated the Onset-to-Door Efficiency Index (ODEI) as transport distance (km) divided by ODT (h). Unfavorable outcome was defined as modified Rankin Scale (mRS) score 4–6 at 3 months. Symptomatic intracranial hemorrhage (sICH) was defined as PH1 or higher according to the ECASS criteria. Early neurological deterioration (END) was defined as a worsening of ≥2 points on the NIHSS within 72 hours of admission. Results: Of 336 screened patients, 274 were included (144 [53%] male; median age, 79 years). Unfavorable outcomes occurred in 120 patients(44%). Transport distance was not associated with unfavorable outcome (PR 0.995; 95% CI, 0.990–1.001; p =0.103; Fig 1A). In contrast, ODEI showed a negative association with unfavorable outcome (PR 0.216; 95% CI, 0.048–0.963; p =0.044; Fig 1B). Transport distance was not associated with sICH, recanalization rate, or END. ODEI was not associated with sICH (PR 0.229; 95% CI, 0.022–2.415; p =0.220; Fig 2) or recanalization rate (PR 0.702; 95% CI, 0.341–1.444; p =0.336; Fig 2), but was negatively associated with END (PR 0.065; 95% CI, 0.005–0.866; p =0.039; Fig 2). Regarding social factors, living with others or residing in a long-term care facility was positively associated with higher ODEI (B 0.042; 95% CI, 0.001–0.864; p =0.046; Fig 3). Conclusions: In AIS patients requiring EVT, not the transport distance itself but rather ODEI, reflecting hospital arrival efficiency, may be associated with prognosis and END. Furthermore, a certain social factor may be linked to hospital arrival efficiency.