The Validity of High-Sensitive Cardiac Troponin I Serum Level in Comparison to Myocardial Perfusion Imaging in Patient with Cardiac Angina

In a person with significant coronary artery disease (CAD), exercise stress can cause reversible myocardial ischemia, which is detectable by single photon emission computed tomography-myocardial perfusion imaging (SPECT-MPI). The aim of present study was to investigate the relationship between post-exercise high-sensitive cardiac troponin I (hs-cTnI) serum levels and result of SPECT-MPI as a gold standard.

In this cross-sectional study, 82 patients with no previous history of CAD or any organic disease were evaluated. hs-cTnI serum levels were monitored 75 minutes after the peaked of exercise (achievement to at least 85% of maximum heart rate), and compared with reversible myocardial ischemia. After 3 months, patients’ prognosis and continued chest pain were evaluated.

The mean age of the patients was 59.4 ± 11.1, and 60 patients (73%) were women. In 29 patients, reversible myocardial ischemia was detected. There was a significant correlation between hs-cTnI serum level and reversible myocardial ischemia (P = 0.005); but no significant relationship was seen with infarcted myocardial tissue (P = 0.063). Based on SPECT-MPI, the hs-cTnI serum amount of 1.6 ng/dl, as likely as hs-cTnI cut-off level, represented the specificity of 70%, sensitivity of 69%, positive predictive value of 55%, and negative predictive value of 80%. There was no significant relationship between hs-cTnI level and prognosis or chest pain after 3 months.

The serum level of hs-cTnI after exercise was higher in the group with reversible myocardial ischemia.