Effect of Blood Pressure Variability During the Acute Period of Subarachnoid Hemorrhage on Functional Outcomes.

Abstract

The association of blood pressure variation with poor outcomes in aneurysmal subarachnoid hemorrhage (aSAH) is unknown. To evaluate the association of systolic blood pressure (SBP) variation and clinical outcomes in aSAH. We conducted a retrospective chart review of all aSAH patients treated at an academic institution between 2007 and 2016. Patient demographics, aSAH characteristics, and blood pressure observations for the first 24 h of admission in 4-h intervals were obtained. SBP variability metrics assessed were mean, standard deviation, maximum, minimum, peak, trough, coefficient of variation, and successive variation. The primary outcome was a composite of the modified Rankin scale as good (0-2) or poor (3-6) at last follow-up. Comparisons between outcome groups were performed. Logistic regression models for each significant SBP metric controlling for potential confounders were constructed. The study population was 202 patients. The mean age was 57 yr; 66% were female. The median follow-up time was 18 mo; 57 (29%) patients had a poor outcome. Patients with poor outcomes had higher standard deviation (17.1 vs 14.7 mmHg, P=.01), peak (23.5 vs 20.0 mmHg, P=.02), trough (22.6 vs 19.2 mmHg, P<.01), coefficient of variation (13.9 vs 11.8 mmHg, P<.01), and lower minimum SBP (101.4 vs 108.4, P<.01). The logistic regression showed that every 1-mmHg increase in the minimum SBP increased the odds of good outcomes (odds ratio=1.03; 95% CI=1.001-1.064; P=.04). Models including other SBP metrics were not significant. Hypotension was found to be independently associated with poor outcomes in patients with aSAH.