Association between Intraoperative Hyperlactatemia and Myocardial Injury after Noncardiac Surgery

Background: Oxygen demand–supply mismatch is supposed to be one of the major causes of myocardial injuries after noncardiac surgery (MINS). Impaired tissue oxygenation during the surgery can lead to intraoperative hyperlactatemia. Therefore, we aimed to evaluate the relationship between intraoperative lactate level and MINS. Methods: A total of 1905 patients divided into groups according to intraoperative hyperlactatemia: 1444 patients (75.8%) into normal (≤2.2 mmol/L) and 461 patients (24.2%) into hyperlactatemia (>2.2 mmol/L) groups. The primary outcome was the incidence of MINS, and all-cause mortality within 30 days was compared. Results: In the crude population, the risks for MINS and 30-day mortality were higher for the hyperlactatemia group than the normal group (17.7% vs. 37.7%, odds ratio [OR]: 2.83, 95% confidence interval [CI]: 2.24–3.56, p < 0.001 and 0.8% vs. 4.8%, hazard ratio [HR]: 5.86, 95% CI: 2.9–12.84, p < 0.001, respectively). In 365 propensity score-matched pairs, intraoperative hyperlactatemia was consistently associated with MINS and 30-day mortality (21.6% vs. 31.8%, OR: 1.69, 95% CI: 1.21–1.36, p = 0.002 and 1.1% vs. 3.8%, HR: 3.55, 95% CI: 1.71–10.79, p < 0.03, respectively). Conclusion: Intraoperative lactate elevation was associated with a higher incidence of MINS and 30-day mortality.