High-Sensitivity Cardiac Troponin I Thresholds to Identify Myocardial Injury After Noncardiac Surgery: A Cohort Study

Background: Myocardial injury after noncardiac surgery (MINS) is common and associated with short-and long-term major cardiovas-cular events. Diagnostic criteria for MINS using Abbott high-sensitivity cardiac troponin I (hs-cTnI) are unknown.Methods: We performed a prospective cohort study of adults who had in-patient noncardiac surgery and measured hs-cTnI (Abbott Labora-tories) on postoperative serum samples collected up to postoperative day 3. The objective was to determine prognostically important hs-cTnI thresholds associated with major cardiac events and death at 30 days after noncardiac surgery. Using Cox proportional iterative analyses, we determined peak postoperative hs-cTnI thresholds associated with the occurrence of the 30-day composite of major cardiac events (ie, nonfatal myocardial infarction after 3 postoperative days, cardiac ar-rest, and congestive heart failure) and death.Results: Of 3953 included patients, 66 (1.7%) experienced the pri-mary outcome at 30 days. Peak hs-cTnI values and associated inci-dence of major cardiac events and death were as follows: < 60 ng/L: 1.0% (95% CI 0.7-1.3); 60 to < 700 ng/L: 8.6% (5.6-13.0); and > 700 ng/L: 27.3% (16.4-41.9). Compared with peak hs-cTnI < 60 ng/L, adjusted hazard ratios were 7.54 (95% CI% 4.27-13.32) for hs-cTnI values of 60 to < 700 ng/L and 26.87 (13.27-54.41) for values > 700 ng/L.Conclusions: Hs-cTnI elevation within the first 3 days after noncardiac surgery independently predicts major cardiac events and death at 30 days. A postoperative hs-cTnI > 60 ng/L was associated with a > 7 -fold increase in the risk of subsequent major cardiac events and mortality at 30 days.