Association between intraoperative hypotension and 30-day mortality, major adverse cardiac events, and acute kidney injury after non-cardiac surgery: A meta-analysis of cohort studies.

BACKGROUND: The association between intraoperative hypotension (IOH) and postoperative outcomes is not fully understood. We performed a meta-analysis to determine whether IOH is associated with increased risk of 30-day mortality, major adverse cardiac events (MACEs) and acute kidney injury (AKI) after non-cardiac surgery.

METHODS: We searched PubMed and Embase through May 2016 to identify cohort studies that investigated the association between IOH and risk of 30-day mortality, MACEs, or AKI in adult patients after non-cardiac surgery. Ascertainment of IOH and assessment of outcomes were defined by the individual study. Considering the level of clinical heterogeneity, adjusted odds ratios (ORs) with 95% confidence interval (CIs) were pooled using a random-effects model. This meta-analysis is registered on PROSPERO (CRD42016049405).

RESULTS: We included 14 cohort studies that were heterogeneous in terms of definition of IOH. IOH alone was associated with increased risk of 30-day mortality (OR 1.29 [95% CI, 1.19-1.41]), MACEs (OR 1.59 [95% CI, 1.23-2.05]), especially myocardial injury (OR 1.67 [95% CI, 1.31-2.13]), and AKI (OR 1.39 [95% CI, 1.09-1.77]). Triple low (IOH coincident with low bispectral index and low minimum alveolar concentration) also predicts increased risk of 30-day mortality (OR 1.32 [95% CI, 1.03-1.68]).

CONCLUSIONS: IOH alone significantly increases the risk of postoperative 30-day mortality, MACEs, especially myocardial injury, and AKI in adult patients after non-cardiac surgery. Triple low also predicts increased risk of 30-day mortality after non-cardiac surgery. These findings provide evidence that IOH should be recognized as an independent risk factor for postoperative adverse outcomes after non-cardiac surgery.