Clinical aspects of the assessment of high-sensitivity troponin T after coronary artery bypass surgery

Abstract

For the diagnosis of myocardial infarction during cardiac surgery, various thresholds for high-sensitivity troponins have been proposed. However, studies show that the actual thresholds can be much higher. The factors associated with increased troponins after coronary artery bypass grafting (CABG) and the relationship of this marker with echocardiographic data remain unexplored.Aim. To determine the clinical value of high-sensitivity troponin T after CABG.Material and methods. The study included 50 patients after CABG. Before and after the operation, a blood test for high-sensitivity troponin T (Cobas E411 analyzer) and echocardiography were performed to determine the left ventricular end-systolic (ESV), end-diastolic volume (EDV) and ejection fraction.Results. Before surgery, in 21 (42%) patients, the marker was higher than the upper normal limit (UNL), by a maximum of 5,9 times. After surgery, 23 (46%) and 2 (4%) patients had more than 10-fold and 35-fold excess of UNL, respectively. When using cardiopulmonary bypass and cardioplegia in all patients, troponin T values were 10 or more times higher than ULN, which is significantly higher (p=0,003 and p=0,018, respectively) than in patients after off-pump surgery. An average positive correlation was found between the number of grafts and troponin T concentration after surgery (r=0,40; p=0,004). At the same time, the relationship with the operation duration was not significant (r=0,19; p=0,191). After the operation, there was a moderate decrease in EDV by an average of 7,4 ml (p<0,001), a decrease in ESV by 3,5 ml (p=0,007) and an increase in ejection fraction by 2,2% (p=0,020). The dynamics of these indicators does not correlate with the troponin T after surgery (|r|<0,2; p>0,05).Conclusion. High-sensitivity troponin T may vary depending on surgery tactics, as a result of which it reflects myocardial ischemic injury directly related to surgical procedures. This elevation is not clinically significant. Evaluation of high-sensitivity troponin T, without taking into account other research methods, cannot be used for a differentiated approach in determining perioperative myocardial infarction and used to make clinical decisions in patients after CABG.