Myocardial Injury After Noncardiac Surgery and Its Association With Short-Term Mortality

Study Questions:

What is the predictive value of postoperative myocardial injury, as measured by troponin elevation, on 30-day mortality after noncardiac surgery?

Methods:

This observational single-center cohort study included 2,232 consecutive intermediate- to high-risk noncardiac surgery patients ages 60 years and above, operated on in 2011. Troponin was measured on the first 3 postoperative days. Log binomial regression analysis was used to estimate the association between postoperative myocardial injury (troponin I level >0.06 mcg/L) and all-cause 30-day mortality.

Results:

Myocardial injury was found in 315 (19%) patients. All-cause death occurred in 56 (3%) patients. The relative risk of a minor increase in troponin (0.07-0.59 mcg/L) was 2.4 (95% confidence interval [CI], 1.3-4.2; p < 0.01), and the relative risk of a 10- to 100-fold increase in troponin (≥0.60 mcg/L) was 4.2 (95% CI, 2.1-8.6; p < 0.01). A myocardial infarction according to the universal definition was diagnosed in 10 patients (0.6%), of which one (0.06%) had ST-segment elevation myocardial infarction.

Conclusions:

The authors concluded that postoperative myocardial injury is an independent predictor of 30-day mortality after noncardiac surgery.

Perspective:

This cohort study estimated the incidence of myocardial injury after noncardiac surgery and its predictive value on the risk of death within 30 days, and reported that troponin I elevation was an independent predictor of 30-day mortality. Implementation of postoperative monitoring of troponin as standard of care is feasible, and may potentially improve risk stratification of patients at risk for early postoperative death. However, additional studies are needed to explore whether there is a causal relationship between myocardial injury and mortality or whether myocardial injury merely indicates a worse outcome, and whether patients with myocardial injury may actually benefit from aggressive postoperative cardiovascular treatment.

Keywords: Cause of Death, Incidence, Risk, Myocardial Infarction, Biological Markers, Heart Injuries, Troponin I, Troponin T


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