Abstract Number: Esoc2026a1145 the Association Between Mean Attenuation of Haematoma With Expansion and Perihaematomal Oedema in Ultra-Acute Intracerebral Haemorrhage: Data From the Right-2 Trial

Background and aims It is unclear whether density of intracerebral haemorrhage (ICH) haematoma in ultra-acute period is associated with expansion, perihaematomal oedema (PHO) and prognosis. We assessed these using data from the RIGHT-2 trial which recruited participants within 4 hours of ictus. Methods Data from 133 participants from RIGHT-2 were included. ICH volume (ICHV) and PHO volume were measured (SAS method, mL) at baseline and 24 hours. Mean ICH density (Hounsfield unit, HU) was assessed. Haematoma expansion (HE) was defined as ICHV > 6ml or 33%. The association between ICH density on HE, PHO, absolute PHO growth, day 4 death and functional outcome at day 90 (modified Rankin scale, mRS >3) was assessed. Results Mean ICH density was 53.12 HU in participants with HE and 53.37 HU in those without (p=0.89). After adjustment for ICHV, onset-to-CT time and intraventricular haemorrhage, ICH density did not predict HE (odds ratio [OR] 0.97, 95%CI 0.91-1.02). Mean ICH density correlated poorly with PHO volume (r=0.086, p=0.31) and not associated with PHO growth (mean difference [MD] 0.14 mL, 95%CI -0.09, 0.52). Baseline ICHV and PHO volume predicted PHO growth at 24 hours (MD 0.66 mL, [95%CI 0.18, 0.44]; and MD -0.40 mL, [95%CI -0.83, -0.14] respectively). After adjustment, ICH density did not predict death at day 4 (OR 0.96, 0.89-1.03) or mRS >3 (OR 0.96, 0.91-1.02). Conclusions ICH density was not associated with HE, PHO, PHO growth or prognosis. The poor correlation between ICH density and PHO volume may reflect mechanisms apart from haematoma contraction. Conflict of interest The RIGHT-2 trial was funded by the British Heart Foundation.