Intraoperative hypotension and adverse postoperative outcomes: a systematic review and meta-analysis of randomised controlled trials.

BACKGROUND: Intraoperative arterial hypotension commonly occurs and is associated with adverse outcomes. Evidence on causality from RCTs is sparse. This meta-analysis aimed to summarise evidence from RCTs that categorise groups based on MAP thresholds, examining the impact on mortality, acute kidney injury (AKI), and myocardial injury in patients undergoing noncardiac surgery. METHODS: A systematic search of PubMed, Embase, and Web of Science was conducted for RCTs in adults undergoing noncardiac surgery that categorised groups based on MAP thresholds. The primary objective was to examine the effect of differences in achieved MAP on the primary outcome of all-cause mortality within 30 days of surgery. AKI, myocardial injury, and MAP achieved in the intervention and control arms were analysed as secondary outcomes. For each study, two groups were identified: an intervention ('higher-pressure' target) group, and a control ('lower-pressure' target) group. Exploratory analysis examined whether the difference in achieved MAP between groups modified the study outcomes. RESULTS: Nine RCTs comprising 14 658 patients did not demonstrate a difference in the primary outcome of all-cause mortality between intervention and control groups (RR: 1.06, 95% CI: 0.77-1.45, I2=0%). No differences were observed for secondary outcomes in 13 RCTs. Differences in intraoperative MAP between study groups were not associated with study outcomes. CONCLUSIONS: Higher vs lower intraoperative MAP did not affect all-cause 30-day mortality, AKI, or myocardial injury; however, only limited differences in blood pressure were achieved between study groups. Stratification by differences in achieved pressure did not alter the results. Systematic review protocol. PROSPERO (CRD420251230069).