Timing of Preoperative Troponin Elevations and Postoperative Mortality After Noncardiac Surgery

Abstract

Even small elevations in preoperative troponin levels have been shown to be associated with adverse outcomes. However, there are currently limited data on the relationship between troponin increase and timing of surgery. We performed a single-institution, retrospective cohort study of 6030 individuals with a troponin measurement made during the 30 days preceding a noncardiac surgical procedure. Subjects with detectable troponin levels were separated into terciles based on both the magnitude of the value and the time elapsed between this value and the surgery. For those undergoing nonemergent procedures, these 9 cohorts were compared with the group of individuals with undetectable preoperative troponin levels using bivariable and multivariable logistic regression. Thirty-day mortality was 4.7% in the group with undetectable troponin levels and increased with higher concentrations, with rates of 8.9%, 12.7%, and 12.7% in the low, medium, and high tercile groups, respectively. Unadjusted risk of 30-day mortality was highest in those with the highest troponin levels and shortest duration between the measurement and surgery (odds ratio, 4.497; 95% confidence interval, 2.058-9.825). After adjusting for subject characteristics, troponin remained associated with 30-day mortality in several groups, including individuals with troponin levels in the normal range. Higher levels of preoperative cardiac troponin I were associated with higher postoperative mortality, and longer time to surgery appeared to reduce this risk for individuals with mild preoperative troponin elevations. Prospective studies are needed to determine whether delaying surgery in patients with elevated preoperative troponin levels improves postoperative outcomes.