Frequency and cause of cardiac troponin T elevation in chronic hemodialysis patients from study of cardiovascular magnetic resonance.

Cardiac troponin T level predicts a gradient risk for death in patients using hemodialysis. We used cardiovascular magnetic resonance (CMR) to determine whether an asymptomatic increase of troponin T in patients using hemodialysis is associated with subclinical myocardial infarction (MI). Twenty-six patients using long-term hemodialysis (49 +/- 12 years of age, 19 men, 8 diabetics) with left ventricular (LV) ejection fraction >40% and no known coronary artery disease were selected based on a low-risk troponin T level </=0.03 ng/ml (median 0.02, interquartile range 0.00 to 0.02, n = 13) and high-risk troponin T level >/=0.07 ng/ml (median 0.15, interquartile range 0.09 to 0.19, n = 13). All underwent CMR imaging for LV mass and for MI by late gadolinium enhancement. Between high- and low-risk patients using hemodialysis, there were no differences in age, gender, ethnicity, or diabetes mellitus. Of the high-risk patients, 3 (23%, 95% confidence interval [CI] 5 to 54) had MI by late gadolinium enhancement versus 0 (0%, 95% CI 0 to 25) low-risk patients (p = 0.22). A diffuse, midwall late gadolinium enhancement pattern was seen in 1 high-risk patient (8%) versus 0 low-risk patient (0%, 95% CI 0 to 25, p = 0.97). Height-adjusted LV mass and LV hypertrophy were not significantly different between high-risk (62 +/- 26 g/m(2.7), LV hypertrophy, n = 7, 54%) and low-risk (54 +/- 20 g/m(2.7), LV hypertrophy, n = 5, 39%) patients (p = 0.37 for LV mass, p = 0.69 for LV hypertrophy). In conclusion, MI detected by CMR is present in few patients on hemodialysis with high troponin T levels and absent in the setting of very low troponin T levels, suggesting that additional myocardial pathologies cause increased troponin T in patients using hemodialysis.