Association of Troponin Trends and Cardiac Morbidity and Mortality After On-Pump Cardiac Surgery.

Background: Elevated, single-measure, postoperative troponin is associated with adverse events after cardiac surgery. We hypothesized that increases in troponin from the first to the second postoperative day are also associated with all-cause, 12-month mortality and major adverse cardiac events (MACE).

Methods: This observational study included consecutive adults undergoing on-pump cardiac surgery with cardiac arrest. Troponin T was measured on the first and second postoperative day and was classified as "increasing" (>10%), "unchanged" (10% to -10%), or "decreasing" (<-10%). The primary endpoint was all-cause, 12-month mortality. Secondary endpoints were all-cause 12-month mortality or MACE and both outcomes at 30 days. The main analysis was by multivariable Cox regression.

Results: Of 1,417 included patients, 99 (7.0%) died and 162 (11.4%) died or suffered MACE at 12 months. A significant interaction (p < 0.001) between first postoperative day troponin and the troponin trend from the first to the second postoperative day on 12-month, all-cause mortality precluded an analysis independent of first postoperative day troponin. Consequently, we stratified patients by their first postoperative day troponin (cutoff, 0.8 μg/L). Increasing troponin was associated with higher mortality in patients with first postoperative day troponin T ≥ 0.8 μg/L (hazard ratio, 1.98; 95% CI, 1.09 to 3.59; p = 0.025).

Conclusions: Troponin changes from the first to the second postoperative day should not be interpreted without consideration of the first postoperative day troponin concentration. For patients with a first postoperative day troponin ≥ 0.8 μg/L, an increase by more than 10% from the first to the second postoperative day was significantly associated with all-cause, 12-month mortality and other adverse events.