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

BACKGROUND AND AIMS: 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. METHODS: 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. RESULTS: 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). CONCLUSION: TnI increase after EST in patients with suspected stable angina is largely independent of the results of coronary angiography and EST.