Impact of Clinical Variables and Aneurysm Morphology on Hemorrhage Volume and Clinical Outcomes.

Background and objectives: It is unknown what determines the volume of aneurysmal subarachnoid hemorrhage (aSAH). We aimed to investigate the features associated to the burden of subarachnoid hemorrhage after aneurysm rupture and its impact on clinical outcomes.

Methods: Patients admitted with aSAH between 2009 and 2022 were included. Clinical data were obtained from electronic medical records. Aneurysm location and morphological measurements were assessed using digital subtraction angiography. aSAH volume was objectively quantified on admission noncontrast computed tomography using semiautomated software. Univariate and multivariate analyses were performed to identify predictors of hemorrhage volume and examine its association with delayed cerebral ischemia (DCI), clinical vasospasm, and 7-day mortality in younger (18-64 years) and elderly (≥65 years) patients.

Results: Two hundred ruptured intracranial aneurysms were analyzed. Ruptured bifurcating aneurysms exhibited larger hemorrhage volume compared with sidewall aneurysms (23.16 mL, IQR: 34.2 vs 11.95 mL, IQR: 20.9, P = .002). In multivariate analysis, age (exp β 1.02; 95% CI 1.01-1.03; P < .001), Hunt and Hess (exp β 1.46, 95% CI: 1.31-1.62, P <.001), and bifurcation aneurysms (exp β 1.76; 95% CI 1.37-2.26; P <.001) were correlated with increased aSAH volume. Among younger patients, higher aSAH volume was associated with DCI (odds ratio [OR] 1.04; 95% CI 1.02-1.06; P < .001), clinical vasospasm (OR 1.02; 95% CI 1.01-1.03; P = .02), and 7-day mortality (OR 1.05; 95% CI 1.02-1.07; P < .001). In elderly population, larger aSAH was only associated with 7-day mortality (OR 1.04; 95% CI 1.01-1.07; P = .01).

Conclusion: Older age, bifurcating aneurysms, and higher Hunt and Hess are associated with larger aSAH volumes. In younger patients, greater aSAH volume is linked to an increased risk of DCI, clinical vasospasm, and 7-day mortality. Among older patients, increased aSAH volume is only associated with 7-day mortality.