Beta-Blockade in Aneurysmal Subarachnoid Hemorrhage: a Systematic Review and Meta-Analysis

Background/objective Sympathetic nervous system activation after aneurysmal subarachnoid hemorrhage (aSAH) is associated with complications and poor outcome. In this systematic review and meta-analysis, we investigate the effect of beta-blockers on outcome after aSAH. Methods The review was prospectively registered with PROSPERO (CRD42019111784). We performed a systematic literature search of MEDLINE, EMBASE, the Cochrane Library, published conference proceedings, and abstracts. Eligible studies included both randomized controlled trials and observational studies up to October 2018, reporting the effect of beta-blocker therapy on the following outcomes in aSAH: mortality, vasospasm, delayed cerebral ischemia, infarction or stroke, cardiac dysfunction, and functional outcomes. Studies involving traumatic SAH were excluded. Citations were reviewed, and data extracted independently by two investigators using a standardized proforma. Results We identified 819 records with 16 studies (four were randomized controlled trials) including 6702 patients selected for analysis. Exposure to beta-blockade either before or after aSAH was associated with a significant reduction in unadjusted mortality (RR 0.63, 95% CI 0.42-0.93, p = 0.02). A significant reduction in unadjusted mortality was also seen in prospective trials of post-event beta-blockade (RR 0.51, 95% CI 0.28-0.93, p = 0.03). Statistically significant differences were not seen for other outcomes investigated. Conclusions In adult patients with aSAH, beta-blocker therapy is associated with a mortality benefit. Studies are generally of a low quality with considerable clinical heterogeneity. Prospective large interventional trials with patient centered outcomes are required to validate this finding.