High hs-cTnT levels predict 30-day mortality after cardiac surgery

Perioperative myocardial injury (PMI), as shown by perioperative high-sensitivity cardiac troponin T (hs-cTnT) release, appears predictive of expected 30-day mortality, but not 5-year mortality, in patients undergoing cardiac surgery, reveals a recent study.

The authors of this study retrospectively analysed a consecutive cohort of 8,292 patients undergoing cardiac surgery with serial perioperative hs-cTnT measurement. Using a Cox proportional hazards model, they assessed the association between postoperative hs-cTnT release and 30-day or 5-year mortality after adjustment with EuroSCORE II.

In addition, the authors determined the hs-cTnT thresholds for 30-day and 5-year mortality for isolated coronary artery bypass grafting (CABG; 32.3 percent), aortic valve replacement (AVR; 14 percent), and other cardiac surgery (53.8 percent).

An association was noted between high postoperative hs-cTnT levels and higher 30-day mortality, but not 5-year mortality. The median peak concentration of postoperative hs-cTnT was 1,044 ng/L in CABG, 502 ng/L in AVR, and 1,110 ng/L in other cardiac procedures.

The threshold of hs-cTnT that defined mortality-related PMI were 2,385 ng/L (170x the upper reference limit of normal in a seemingly healthy population [URL]) for CABG, 568 ng/L (41x URL) for AVR, and 1,873 ng/L (134x URL) for other cardiac surgery.

In addition, hs-cTnT levels above the cutoffs correlated with a higher risk for 30-day mortality: 12.56 for CABG (p<0.001), 4.44 for AVR (p=0.004), and 3.97 for other cardiac surgery (p<0.001).

“Postoperative hs-cTnT cutoffs to identify survival-relevant PMI are higher than suggested in current definitions,” the authors said.