Prognostic Value of Early Postoperative Troponin T in Patients Undergoing Coronary Artery Bypass Grafting

BACKGROUND Cardiac troponin T (cTnT) is elevated after coronary artery bypass grafting surgery. The aim of this study was to determine the association between cTnT elevations between 6 and 12 hours after coronary artery bypass grafting and in-hospital outcome. METHODS AND RESULTS We prospectively studied 1722 patients undergoing isolated coronary artery bypass grafting. We assessed the association between conventional cTnT (749 patients) and high-sensitivity cTnT (hs-cTnT; 973 patients) 6 to 12 hours postoperatively with in-hospital major adverse cardiac or cerebrovascular events (MACCE), a composite of all-cause death, myocardial infarction, or stroke. The prespecified secondary outcome was a safety composite of MACCE, resuscitation, intensive care unit readmission or admission ≥48 hours, inotrope or vasopressor use ≥24 hours, or new-onset renal insufficiency. Among patients with a conventional cTnT measurement, 92 experienced a MACCE (12%) and 146 experienced a safety composite event (19%). Likewise, for hs-cTnT, 114 experienced a MACCE (12%) and 153 experienced a safety composite event (16%). Compared with cTnT ≤200 ng/L, each 200-ng/L increment in cTnT was associated with a monotonous increase in the odds of MACCE and the safety composite outcome. Conventional and hs-cTnT demonstrated moderate discrimination for MACCE (areas under the fitted receiver operating characteristics curve, 0.72 and 0.77 for conventional and hs-cTnT, respectively) and the safety composite outcome (areas under the fitted receiver operating characteristics curve, 0.66 and 0.74 for conventional and hs-cTnT, respectively) and resulted in improved prognostic performance when added to the EuroSCORE. At a cutoff of 800 ng/L, conventional and hs-cTnT provided clinically relevant power to rule in MACCE and the safety composite outcome. CONCLUSIONS cTnT levels assessed between 6 and 12 hours after coronary artery bypass grafting identify patients at increased risk of MACCE or other complications.