Perioperative Factors Associated With Changes in Troponin T During Coronary Artery Bypass Grafting

Abstract

Objective: Investigate important clinical and operative variables associated with increases in cardiac troponin T (cTnT) as indicators of myocardial injury after coronary artery bypass grafting (CABG).

Design: Prospective cohort study.

Setting: Single university hospital.

Participants: The study comprised 626 patients undergoing isolated CABG from April 2008 through April 2010 with a validation cohort (n = 686) from 2015-2017.

Interventions: None.

Measurements and main results: Perioperative variables were registered prospectively. The extent of diffuse coronary atherosclerosis and significant stenoses were assessed with preoperative coronary angiography. Mixed model analysis was used to construct a statistical model explaining the course of cTnT concentrations. The model was adjusted for preoperative and intraoperative/postoperative myocardial infarction (MI) for independent assessment of additional variables. Clinical factors associated with increased cTnT concentrations during and after CABG were longer duration of cardiopulmonary bypass (p < 0.001), higher preoperative creatinine (p < 0.001), New York Heart Association functional classification IV (p = 0.006), reduced LVEF (p = 0.034), higher preoperative C-reactive protein (p = 0.049), and intraoperative/postoperative MI (p < 0.001). Factors associated with decreasing cTnT concentrations during CABG were higher BSA (p < 0.001) and a recent preoperative MI (p < 0.001). The extent of diffuse coronary atherosclerosis and significant stenoses were not associated with changes in cTnT (p = 0.35). Results were similar in the validation cohort.

Conclusions: Left ventricular ejection fraction, New York Heart Association classification, kidney function, inflammation status, duration of cardiopulmonary bypass, body surface area, and preoperative MI were associated with the cTnT rise-and-fall pattern related to myocardial injury after CABG. Information regarding these variables may be valuable when using cTnT in the diagnostic workup of postoperative MI.

Keywords: coronary artery bypass grafting; myocardial infarction; troponin T.