Abstract Number: Esoc2026a730 Intervention or Conservative Management of Symptomatic Cerebral Cavernous Malformations: A Prospective, Population-Based Cohort Study

Abstract Background and aims There is ongoing clinical equipoise regarding the optimal treatment strategy for symptomatic cerebral cavernous malformations (CCM). We evaluated associations between CCM intervention versus conservative management and clinical outcomes during long-term follow-up. Methods This prospective, population-based cohort study included adults (aged ≥16 years) newly diagnosed with CCM in Scotland during 1999-2003 or 2006-2010. Using Cox regression, we analyzed “persistent functional impairment (≥2 consecutive annual Oxford Handicap Scale OHS score ratings 2-6)” and “symptomatic intracranial hemorrhage (ICH) or new non-haemorrhagic focal neurological deficit (FND)” during follow-up, including treatment status as time-dependent covariate. We further included age, sex, type of inception symptoms, brainstem CCM, multiple CCMs, and largest CCM diameter, and for “persistent functional impairment” also socioeconomic status and inception OHS score. Results Of 306 adults with CCM, 190 were symptomatic (89 47% due to ICH/FND, 101 53% due to epileptic seizure(s); median age 40 years IQR 31-55; 50% women). During 2,989 person-years of follow-up (median 16 IQR 14-20, completeness 95%), 37 (19%) adults underwent CCM intervention (n = 35 microsurgical resection, n = 2 stereotactic radiosurgery); they were younger (33 26-40 versus 43 32-59 years, P 0.001) and had brainstem CCM less often (3/37 8% versus 36/153 24%, P = 0.037) than adults managed conservatively. We did not find evidence that CCM treatment status was associated with persistent functional impairment (adjusted HR 1.26 95% CI 0.66-2.42, P = 0.479) or new ICH/FND (adjusted HR 2.82 0.97-8.23, P = 0.057). Conclusions We did not find a difference in clinical outcomes between intervention and conservative management for CCM in the long term. Conflict of interest ACAS: nothing to disclose; DV: nothing to disclose; JMC: nothing to disclose; WPV: nothing to disclose; PMW: nothing to disclose; RASS: nothing to disclose.