Postoperative Myocardial Injury in Patients Classified as Low Risk Preoperatively Is Associated With a Particularly Increased Risk of Long-Term Mortality After Noncardiac Surgery.

Background Prior studies have shown an association between myocardial injury after noncardiac surgery (MINS) and all-cause mortality in patients following noncardiac surgery. However, the association between preoperative risk assessments, Revised Cardiac Risk Index and American College of Surgeons National Surgical Quality Improvement Program, and postoperative troponin elevations and long-term mortality is unknown. Methods and Results A retrospective chart review identified 548 patients who had a troponin I level drawn within 14 days of noncardiac surgery that required an overnight hospital stay. Patients aged 40 to 80 years with at least 2 cardiovascular risk factors were included, while those with trauma, pulmonary embolism, and neurosurgery were excluded. Kaplan-Meier survival and odds ratio (OR) with sensitivity/specificity analysis were performed to assess the association between preoperative risk and postoperative troponin elevation and all-cause mortality at 1 year. Overall, 69%/31% were classified as low-risk/high-risk per the Revised Cardiac Risk Index and 66%/34% per American College of Surgeons National Surgical Quality Improvement Program. Comparing the low-risk versus high-risk groups, preoperative risk assessment was not associated with either postoperative troponin elevation or 1-year mortality. MINS portended a 1-year mortality of OR, 3.9 (95% CI, 2.44-6.33) in the total population. Patients classified as low risk preoperatively with MINS had the highest risk of 1-year mortality (OR, 9.6; 95% CI, 4.27-24.38), with a low prevalence of statin use. Conclusions Current preoperative risk stratification tools do not prognosticate the risk of postoperative troponin elevation and all-cause mortality at 1 year. Interestingly, patients classified as low risk preoperatively with MINS had a markedly higher 1-year mortality risk compared with the general population, and most of them are not taking a statin. Our results suggest that evaluating preoperatively low-risk patients for MINS presents an opportunity for prognostication, risk reclassification, and initiating therapies such as statins to mitigate long-term risk.