Objective:

We investigated the relationship between high-sensitivity cardiac troponin T (hs-cTnT), which has been recently introduced in many emergency departments because of its very high negative predictive value in the diagnosis and differential diagnosis of non-ST elevated myocardial infarction (NSTEMI), and serum bilirubin levels.

Methods:

A total of 371 patients who admitted to the emergency department with the complaint of chest pain and hs-cTnT (+), were hospitalized with the diagnosis of NSTEMI and who underwent coronary angiography, and 374 patients with hs-cTnT (-) as the control group were included in the study. Serum bilirubin levels (total and direct) were studied and compared between the two groups. In addition, the median SYNTAX (SX) score was determined in hs-cTnT (+) patient group and a sub-analysis was performed. Accordingly, bilirubin levels were investigated between the group with low SX scores (<12) and the group with high SX scores.

Results:

When bilirubin levels were compared; no significant difference was found between hs-cTnT (+) and hs-cTnT (-) groups in terms of both total and direct bilirubin values, with total bilirubin being at the limit (total bilirubin, p=0.05; direct bilirubin, p=0.42; respectively). In the correlation analysis, a moderate positive correlation was found only between hs-cTnT and total bilirubin (r=0.43, p=0.042). When the correlation of total and direct bilirubin with SX score was examined; both total and direct bilirubin values were decreased as the SX score was increased, but this negative correlation was not statistically significant.

Conclusion:

The results of this study show that serum bilirubin, which has been shown in numerous studies to be significantly associated with cardiac troponins (I and T), even an independent predictor of high troponin levels in NSTEMI, has a low sensitivity against cardiomyocyte damage in very early period. In our study, we could not find a correlation between bilirubin values and hs-cTnT. However, considering the severity of coronary artery disease, high bilirubin levels were found in patients with a low SX score (median SX score=12 in this study) in the regression analysis, supporting a negative correlation independently from myocardial infarction and hs-cTnT levels as reported in previous studies.

Keywords: Bilirubin, high-sensitivity cardiac troponin T, non-ST elevated myocardial infarction