Blood pressure changes after aneurysmal subarachnoid hemorrhage and their relationship to cerebral vasospasm and clinical outcome

Abstract

Objective: Cerebral vasospasm (VS) and resulting delayed ischemic brain injury constitute the most severe secondary complication after subarachnoid hemorrhage (SAH). Identification of early clinical predictors of developing vasospasm and poor outcome has remained a major challenge in neurointensive care medicine. Aim of the present study was analyze the relevance of spontaneous changes in blood pressures and their predictive value for predicting vasospasm as well as adverse clinical outcome.

Methods: 98 aneurysmal SAH patients were analyzed retrospectively. Patients were divided into two study groups: (1) VS+ (developing VS) and (2) VS- (not developing VS). Repeat-angiography was routinely performed on day 8 after SAH or earlier if clinical signs were suggestive for overt vasospasm. Systolic, diastolic and mean blood pressures were averaged hourly and plotted over time. Secondly, blood pressure (BP)-progression was analyzed with respect to clinical outcomes as assessed by the Glasgow outcome scale.

Results: Mean, systolic, and diastolic blood pressure values progressed in both VS- and VS+ cohorts over time. However, as early as 4 days after SAH a significant dissociation of RR curves was observed between the groups with patients in the VS+ group displaying a significantly higher slope coefficient of blood pressure elevation. An increase of mean arterial pressure >20% within the first 4 days was predictive of developing vasospasm. Elevation of mean arterial blood pressure in the VS+ group was mainly attributable to changes in diastolic pressure. Elevation of mean arterial blood pressure >25% within the first week after SAH was associated with unfavorable outcome.

Conclusions: SAH leads to spontaneous and progressive elevations in mean arterial blood pressure. Vasospasm might be anticipated by identifying early elevations of mean arterial blood pressure. Finally, spontaneous elevations of mean arterial blood pressure correlate with poorer outcomes.

Keywords: Aneurysm rupture; Blood pressure; Glasgow outcome scale; Subarachnoid hemorrhage; Vasospasm.