Abstract Number: Esoc2026a348 Discrepancies Between Estimated and Measured Body Weight in Intravenous Thrombolysis for Acute Ischemic Stroke

Abstract Background and aims Accurate body weight is essential for tissue plasminogen activator (tPA) dosing in acute ischemic stroke, yet estimated weight is often used. We quantified discrepancies between estimated and measured weight and assessed clinical impact. Methods Among 479 consecutive patients who received intravenous tPA (0.6mg/kg) at our institution between January 2019 and June 2025, we excluded those who underwent mechanical thrombectomy and those without measured weight within 2 days. A total of 128 patients treated with tPA based on self-reported or visually estimated weight were included. Differences between estimated and measured weight were assessed using mean error (ME), mean absolute error (MAE), mean absolute percentage error (MAPE), and MAE of tPA dose. Patients were categorized by initial NIHSS into mild (0–5), moderate (6–14), and severe (≥15) groups. Results The median age was 78 years, and 50 patients were women. The median onset-to-needle time was 2.5 hours. Mean estimated and actual weights were 60.5 kg and 59.8 kg (R2=0.90), respectively. ME was +0.29 kg, MAE was 3.1 kg, and MAPE was 5.2%. The MAE of tPA dose was 1.9 mg. MAPE increased with severity (mild 4.1%, moderate 5.4%, severe 8.1%), with greater error in severe than mild group (P = 0.008). Intracranial hemorrhage occurred in 11 patients (8.5%), including 3 symptomatic cases (2.3%). Overdosing of ≥4% was associated with higher intracranial hemorrhage risk (adjusted OR 3.8, 95% CI 1.05–13.90; P = 0.042). Conclusions Estimated body weight differed from measured weight, resulting in dosing errors, and overdosing was associated with intracranial hemorrhage. Conflict of interest Kota Maekawa: nothing to disclose, Noriko Nomura: nothing to disclose, Nobuyuki Ohara: nothing to disclose, Tsuyoshi Ohta: nothing to disclose, Michi Kawamoto: nothing to disclose