CARDIAC TROPONIN-I IN PATIENTS RECEIVING RENAL REPLACEMENT THERAPY

Current markers of myocardial injury lack specificity in patients with end-stage renal disease (ESRD). In particular, a false positive creat ine kinase-MB (CKMB) elevation occurs in 5-10% of patients with ESRD. The aim of this study was to ascertain the relationship between CKMB a nd cardiac troponin I (cTnI), a new, highly sensitive and specific mar ker for myocardial injury, in the authors' dialysis population and com pare their specificities. Blood samples were obtained from 112 dialysi s patients (35 in peritoneal dialysis; 77 in hemodialysis). Patients w ere asymptomatic for cardiac ischemia and skeletal muscle injury. Mean +/- SD CKMB mass was 3.16 +/- 2.26 mu g/L (range, 0.34-13.62), and cT nI was 0.025 +/- 0.061 ng/ml (range, 0.001-0.496). CKMB and cTnI level s did not correlate (r(2) = 0.002; p = 0.61). CKMB mass concentration was significantly higher in men and in diabetics. No patient had a cTn I level greater than 1.5 mu g/L, and eight asymptomatic patients had a CKMB mass greater than 6.7 mu g/L. These data suggest a specificity o f 100% for cTnI vs 94.6% for CKMB at these cutoff values. It is sugges ted that cTnI replace CKMB as a marker of myocardial injury in patient s with ESRD.