Differential associations of cardiac troponin T and cardiac troponin I with coronary artery pathology and dynamics in response to short-duration exercise.

BACKGROUND

We aimed to assess the associations between cardiac troponin (cTn) T and I concentrations, physical exercise and the presence and severity of angiographic coronary artery disease (CAD) in patients evaluated for suspected chronic coronary syndrome (CCS).

METHODS AND RESULTS

All patients performed an exercise stress test on a bicycle ergometer and underwent invasive coronary angiography with weighted anatomical evaluation using the Gensini score. Blood samples were collected before and after exercise and analysed with high-sensitivity (hs) cTnT and cTnI assays. Of 297 patients (median age 62 (Quartile [Q]1-3 56-69) years, 35% female), 46% were categorized as "severe CAD" (Gensini score ≥ 20). Resting hs-cTnT and hs-cTnI concentrations were detectable in 88% and 100% of patients, with medians of 6 (Q1-3 4-9) ng/L and 1.5 (0.9-2.4) ng/L, respectively. In adjusted normalized linear regression analyses, higher resting concentrations were associated with increasing Gensini score (hs-cTnT: B 0.19, 95% Confidence Interval [CI] [0.09-0.41], p < 0.001; hs-cTnI: B 0.18, [0.06-0.30], p = 0.002). The area under the receiver operating characteristics curve for predicting severe CAD was 0.72 (95% CI [0.66-0.78]) and 0.68 (0.62-0.74) for resting hs-cTnT and hs-cTnI, p = 0.11 for difference. The median (Q1-3) relative increase in hs-cTnT and hs-cTnI concentrations were 5 (0-12) % and 13 (3-27) %, respectively, with no significant associations with CAD severity.

CONCLUSIONS

In patients with suspected CCS, higher hs-cTn concentrations at rest were associated with increasing angiographic severity of CAD, without any significant differences between the troponin isotypes. Post-exercise hs-cTn concentrations did not have discriminatory power for CAD.