Blood Pressure Targets After Aneurysmal Subarachnoid Hemorrhage: Is Lower Better?

Abstract

Blood pressure (BP) control before aneurysm treatment is an accepted means of preventing rebleeding after aneurysmal subarachnoid hemorrhage (aSAH). Controversy remains surrounding the optimal systolic BP (sBP) below which patients should be maintained before aneurysm repair. The objective of this work was to determine whether there is an optimal maximal sBP cut point below or above which individuals have improved functional outcomes at 3 months. We performed a post hoc analysis of the CONSCIOUS-1 clinical trial data. The primary outcome was favorable functional outcome at 3 months (modified Rankin scale 0-2). The independent variable of interest was the subject's maximal sBP between admission and aneurysm repair. We assessed the relationship between maximal sBP and functional outcome using logistic regression modeling, and known potential confounders were tested in the model. We calculated an optimal cut point for maximal sBP and favorable functional outcome using the Youden index calculation. Regression modeling was repeated using the cut point as a dichotomized predictor of interest. Three hundred ninety four patients were included in this analysis. The average maximal sBP for patients with good functional outcomes at 3 months was 145 mm Hg compared with 155 mm Hg for those who had poor functional outcomes ( P < .001). The results of our unadjusted regression model suggest patients with lower BP before aneurysm repair were more likely to achieve a favorable functional outcome at 3 months (odds ratio = 1.01, 95% CI 1.00-1.02). The optimal cut point for maximal sBP identified by the Youden index calculation was 118 mm Hg. Using this binary cut point to replace the maximal sBP in our model, we found that individuals who maintained a sBP lower than the optimal cut point were more likely to have a favorable outcome (odds ratio = 0.28, 95% CI 0.07-0.83). These data suggest lower maximal sBP (below 118 mm Hg) in unsecured aneurysm is safe and may be associated with improved functional outcomes at 3 months.