Perioperative myocardial necrosis in patients at high cardiovascular risk undergoing elective non-cardiac surgery

Abstract

Objective: Cardiovascular complications are important causes of morbidity and mortality in elective non-cardiac surgery. Although difficult to diagnose, perioperative myocardial infarction (MI) remains prognostically important. High-sensitivity troponin T (hs-TnT) assays allow detection of very minor damage to cardiac muscle. These assays are yet to be fully evaluated in the perioperative setting. Our aim was to determine the incidence and predictors of myocardial necrosis in patients at high cardiovascular risk undergoing elective non-cardiac surgery using hs-TnT.

Design: Prospective observational cohort study.

Patients: 352 consecutive patients undergoing elective major non-cardiac surgery prescribed antiplatelet therapy for primary or secondary cardiovascular event prevention.

Main outcome measure: The incidence of elevated preoperative hs-TnT (≥14 ng/litre), hs-TnT-defined perioperative myocardial necrosis (≥ 14ng/litre and 50% increase from preoperative level), and perioperative MI were determined in relation to patient and surgical factors.

Results: Preoperative hs-TnT was elevated in 31% and postoperative myocardial necrosis occurred in 22% of patients. Predictors of elevated baseline hs-TnT included age (OR 1.10, p<0.001), male gender (OR 2.91, p<0.001), diabetes requiring insulin therapy (OR 4.85, p=0.004) and chronic kidney disease (OR 3.60, p<0.001). Independent predictors of perioperative myocardial necrosis were age (OR 1.07, p<0.001), intraoperative hypotension (OR 3.67, p=0.001) and orthopaedic surgery (OR 2.46, p=0.005). Only 2% of patients suffered clinically apparent MI. Elevated preoperative hs-TnT did not predict perioperative myocardial necrosis or MI.

Conclusions: Perioperative myocardial damage occurs frequently in patients undergoing elective non-cardiac surgery, although the majority of events are clinically undetected. Age and intraoperative hypotension are independent predictors of myocardial necrosis in this setting.