Postoperative Troponin T and Mortality After Noncardiac Surgery
What is the association between perioperative high-sensitivity troponin T (hsTnT) measurements and 30-day mortality and potential diagnostic criteria for myocardial injury after noncardiac surgery (MINS)?
This was a prospective cohort study of patients aged ≥45 years who underwent inpatient noncardiac surgery and had a postoperative hsTnT measurement. Participants were recruited at 23 centers in 13 countries. Patients had hsTnT measurements 6-12 hours after surgery and daily for 3 days and 40.4% had a preoperative hsTnT measurement. A modified Mazumdar approach (an iterative process) was used to determine if there were hsTnT thresholds associated with risk of death and had an adjusted hazard ratio (HR) of ≥3.0 and a risk of 30-day mortality of ≥3%. To determine potential diagnostic criteria for MINS, regression analyses ascertained if postoperative hsTnT elevations required an ischemic feature (e.g., ischemic symptom or electrocardiography finding) to be associated with 30-day mortality.
Among the 21,842 participants, the mean age was 63.1 (standard deviation, 10.7) years and 49.1% were female. Death within 30 days after surgery occurred in 266 patients (1.2%; 95% confidence interval [CI], 1.1%-1.4%). Multivariable analysis demonstrated that compared with the reference group (peak hsTnT <5 ng/L), peak postoperative hsTnT levels of 20 to <65 ng/L, 65 to <1000 ng/L, and ≥1000 ng/L had 30-day mortality rates of 3.0% (123/4049; 95% CI, 2.6%-3.6%), 9.1% (102/1118; 95% CI, 7.6%-11.0%), and 29.6% (16/54; 95% CI, 19.1%-42.8%), with corresponding adjusted HRs of 23.63 (95% CI, 10.32-54.09), 70.34 (95% CI, 30.60-161.71), and 227.01 (95% CI, 87.35-589.92), respectively. An absolute hsTnT change of ≥5 ng/L was associated with an increased risk of 30-day mortality (adjusted HR, 4.69; 95% CI, 3.52-6.25). An elevated postoperative hsTnT (i.e., 20 to <65 ng/L with an absolute change ≥5 ng/L or hsTnT ≥65 ng/L) without an ischemic feature was associated with 30-day mortality (adjusted HR, 3.20; 95% CI, 2.37-4.32). Among the 3,904 patients (17.9%; 95% CI, 17.4%-18.4%) with MINS, 3,633 (93.1%; 95% CI, 92.2%-93.8%) did not experience an ischemic symptom.
The authors concluded that among patients undergoing noncardiac surgery, peak postoperative hsTnT during the first 3 days after surgery was significantly associated with 30-day mortality.
This study reports that a postoperative hsTnT measurement of ≥20 ng/L was associated with 30-day mortality with no interaction based on renal function or sex. This is the second large study reporting that the diagnostic criteria for MINS do not require an ischemic feature, and supports the MINS diagnostic criteria of an elevated postoperative hsTnT judged as resulting from myocardial ischemia without the requirement of an ischemic feature. Most patients experiencing MINS do not receive secondary-prevention cardiovascular drugs (e.g., aspirin, statins), despite observational studies suggesting that these medications prevent mortality and major cardiac complications, and optimal secondary prevention can be the focus of quality improvement initiatives.
Keywords: Acute Coronary Syndrome, Biological Markers, Coronary Artery Disease, Electrocardiography, Myocardial Ischemia, Postoperative Period, Quality Improvement, Risk, Secondary Prevention, Surgical Procedures, Operative, Troponin, Troponin T
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