ABSTRACT NUMBER: ESOC2026LB201 DOAC PLASMA LEVELS AND RISK OF HEMATOMA EXPANSION IN DOAC-ASSOCIATED INTRACEREBRAL HEMORRHAGE: AN INTERNATIONAL MULTICENTER STUDY

Abstract Background and aims In DOAC-associated ICH, hematoma expansion (HE) is a key driver of poor outcomes. We aimed to investigate whether higher DOAC plasma levels are associated with HE and whether specific thresholds could inform early risk stratification. Methods Retrospective international multicenter cohort study of patients with DOAC-associated ICH admitted ≤8 hours from symptom onset. DOAC levels were measured ≤4 hours after admission. HE was defined as ≥35% hematoma volume increase between admission and 48-hour scans, symptomatic HE as concurrent ≥4-point NIHSS increase. Multivariable models were adjusted for baseline ICH volume, onset-to-imaging time, systolic blood pressure and reversal use. Results In this preliminary analysis, 260 patients were included (age 79.4±8.2 years; 53% male; NIHSS 13 (IQR 7-19)). The majority received factor Xa inhibitors (97.7%), while dabigatran was used in 2.3% (median DOAC level: 92.5 ng/mL (47.5-177.2)). Symptomatic HE occurred in 56 patients (21.5%). In continuous analysis, each 50-ng/mL increase in DOAC level was associated with 13% higher odds of symptomatic HE (aOR 1.13, 95%CI 1.01–1.27; p=0.036). Levels ≥100n g/mL were associated with higher odds of symptomatic HE (aOR 1.98, 95% CI 1.05–3.74; p=0.035). At very high levels ≥ 300ng/mL, effect estimates suggested a trend toward higher risk (aOR 2.19, 95%CI 0.87–5.54; p=0.096). In contrast, no association was observed between DOAC levels and imaging-defined HE (p=0.49). Conclusions Higher DOAC plasma levels were associated with increased odds of symptomatic HE. DOAC levels may complement intake history for early risk stratification and inform plasma level-guided reversal strategies. Conflict of interest Figure 1 - belongs to Results