The predictive value of cardiac troponin T measurements in subjects on regular haemodialysis

Background. Cardiac troponin T (cTnT) is a subunit of the cardiac actin-myo sin complex, which leaks into the circulation when myocardial necrosis is p resent. Detection of cTnT is associated with a poor outcome in patients wit h unstable angina, and is a. useful tool for risk stratification. The value of cTnT determination in patients with renal failure has been questioned, and the specificity of cTnT in this particular group has not been establish ed. Methods. In the present study, 94 patients at a single centre were followed prospectively after three determinations of cTNT, at 1-month intervals. Th e outcome after 12 months was chosen as the end-point, cTnT was measured us ing both a quantitative chemiluminiscence immunoassay and a qualitative rap id bedside immunoassay on a test strip. The maximum of three measurements w as used and was correlated with different parameters and outcome. The follo wing statistical tests were performed: Kaplan-Meier analysis, Cox's proport ional regression analysis for measuring survival and logistic regression fo r analysing factors influencing cTnT. Results. Forty seven of the 94 patients had a positive cTnT by test strip d efined as > 0.10 ng/ml. Twenty four patients died in the follow-up period ( 14 from cardiovascular causes). Twenty of the 24 non-survivors had an incre ased cTnT by test strip and 23 had increased cTnT by laboratory immunoassay . The outcome analysed by a Cox's proportional regression analysis showed t hat the factors which influenced survival significantly were cTnT, the pres ence of ischaemic heart disease, C-reactive protein (CRP) and prealbumin. A logistic multivariate analysis revealed that age and CRP significantly inf luenced cTnT. A good correlation was found between cTnT determined by test strip and in the laboratory. Conclusion. cTnT is elevated in a large number of patients on regular haemo dialysis and is a significant independent predictor of outcome. Increased c TnT is significantly predicted by age and CRP.