Postexercise troponin I levels in patients with suspected stable ischemic heart disease

Previous studies showed that troponin blood levels may increase after exercise. In this study, we assessed whether, among patients with suspected of having stable angina, the increase in troponin I (TnI) levels after exercise stress test (EST) might help identify those with obstructive coronary artery disease (CAD) and myocardial ischemia.

We performed maximal treadmill EST in 50 patients (age 64 ± 9 years; 38 men) admitted to our Cardiology Department to undergo elective coronary angiography because of a suspicion of stable angina. TnI was measured before and 12 h after EST.

TnI increased after EST compared with baseline in the whole population (from 0.44 ± 0.76 to 0.84 ± 1.12 ng/dl, P < 0.001). No difference in TnI increase was observed between patients with obstructive CAD (n = 29; 0.61 ± 0.90-1.13 ± 1.33 ng/dl) and no obstructive CAD (NO-CAD; n = 21; 0.21 ± 0.46-0.44 ± 0.54 ng/dl; P = 0.51). There was also no significant difference in post-EST TnI increase between patients with positive EST (n = 34; 0.56 ± 0.89-1.05 ± 1.28 ng/dl) or negative EST (n = 16; 0.19 ± 0.26-0.39 ± 0.43 ng/dl; P = 0.16). Moreover, no significant difference was observed in the post-EST TnI increase among groups of patients with positive EST and obstructive CAD, positive EST and NO-CAD, negative EST and obstructive CAD and negative EST and NO-CAD (P = 0.12). No clinical or EST variable was associated with post-EST TnI increase, although there was a tendency for a greater increase in those achieving a heart rate more than 85 vs. less than 85% of maximal predicted heart rate during EST (P = 0.075).

TnI increase after EST in patients with suspected stable angina is largely independent of the results of coronary angiography and EST.