Comparison of the Effects of Blood Pressure Parameters on Rebleeding and Outcomes in Unsecured Aneurysmal Subarachnoid Hemorrhage

Background: Elevated systolic blood pressure (SBP) has been linked to preprocedural rebleeding risk and poor outcome in patients with aneurysmal subarachnoid hemorrhage (aSAH). This study seeks to compare the effects of SBP and mean arterial pressure (MAP) on rebleeding and functional outcomes in aSAH patients.

Methods: We performed a retrospective study of a prospectively collected cohort of consecutive patients with aSAH admitted to an academic center in 2016-2023. Binary regression analysis was used to determine the association between BP parameters and outcomes including rebleeding and poor outcome defined as modified Rankin Scale 4-6 at 3 months postdischarge.

Results: The cohort included 324 patients (mean age 57 years [standard deviation 13.4], 61% female). Symptomatic rebleeding occurred in 34 patients (11%). Higher BP measurements were recorded in patients with rebleeding and poor outcome, however, only MAP met statistical significance for rebleeding (odds ratio {OR} 1.02 for 1 mmHg increase in MAP, 95% confidence interval {CI}: 1.001-1.03, P = 0.043; OR 1 per 1 mmHg increase in SBP, 95% CI 0.99-1.01; P = 0.06)) and for poor outcome (OR 1.01 for 1 mmHg increase in MAP, 95% CI: 1.002-1.025, P = 0.025; OR 1 for 1 mmHg increase in SBP, 95% CI: 0.99-1.02, P = 0.23) independent of other predictors.

Conclusions: MAP may appear to be slightly better correlated with rebleeding and poor outcomes in unsecured aSAH compared to SBP. Larger prospective studies are needed to identify and mitigate risk factors for rebleeding and poor outcome in aSAH patients.