Natural History and Predictors for Hemorrhage in Supratentorial Brain Arteriovenous Malformations

Background/Objectives: Approximately half of the patients harboring supratentorial brain arterio-venous malformations (stAVMs) present with hemorrhage, and another considerable proportion suffer from epileptic seizures. An important milestone in the management of this vascular pathology is acknowledging their natural history, especially across long periods of time. The aim of this study was to assess the predictive factors for hemorrhage and for epileptic seizures as presenting symptoms in stAVMs. Methods: We retrospectively analyzed patients with stAVMs admitted to our institution between 2012 and 2022 and evaluated predictive factors for hemorrhage and the risk factors associated with epileptic seizures. Results: The cohort included 169 patients, 78 of them (46.2%) presenting with intracerebral hemorrhage (ICH). Seventy-seven (45.5%) patients suffered from epileptic seizures. The annual hemorrhagic rate was 1.28%/year. Unruptured lesions (p = 0.001, OR 3.1, 95% CI 1.6-6.2), superficial venous drainage (p = 0.007, OR 2.7, 95% CI 1.3-5.7) and large nidus size (p = 0.025, OR 4, 95% CI 1.2-13.5) were independently associated with seizures. Among unruptured lesions, superficial venous drainage (OR 2.6, p = 0.036, 95% CI 1.06-6.3) and frontal/temporal/parietal location (OR 2.7, p = 0.040, 95 CI% 1.04-6.9) significantly increased the risk of seizures as a presenting symptom in multivariate analysis. Patients younger than 18 (p = 0.003, OR 4.5, 95% CI 1.6-12.2), those with AVMs < 3 cm (p = 0.03, OR 2, 95% CI 1.07-3.9) or those with deep located AVMs (p = 0.035, OR 2.3, 95% CI 1.06-5.1) presented statistically more often with ICH in multivariate regression. Small size (HR 1.8, 95% CI 1.09-3, p = 0.022) and exclusively deep venous drainage (HR 2.2, 95% CI 1.2-4, p = 0.009) were independent predictors for ICH, in time-dependent birth-to-diagnosis analysis. After shifting the birth-to-diagnosis curve by 10 years, unique arterial feeder demonstrated a positive correlation with ICH presentation as well. Conclusions: Small AVMs, those with exclusively deep venous drainage, unique arterial feeder or deep location may pose higher hemorrhagic risks for the patient, and therapeutic strategies should be tailored accordingly. When managing unruptured brain AVMs, it is important to consider the risk of developing seizures, in addition to the lifelong risk of hemorrhage, in determining the optimal treatment approach for each patient.