Behaviour and Prognostic Value of Serum Cardiac Troponin I in Patients with End-Stage Renal Disease Undergoing Long-Term Haemodialysis. A Five-Year Outcome Analysis

Cardiac Troponin I (cTnI) levels are considered an important diagnostic tool in acute coronary events. However, there is controversy over their sensitivity, specificity and prognostic value in haemodialysis (HD) patients. The aim of this study was to explore the behaviour and prognostic value of cardiac troponin I in HD patients. Thirty-four asymptomatic patients undergoing long-term haemodialysis were studied. Samples of blood were collected at the start of the study (pre- and post-dialysis serum), after three years (pre-dialysis serum and plasma, with and without the addition of heterophilic antibody-blocking reagent (HBR) and after five years (pre-dialysis serum). Quantitative cardiac troponin I was measured with an AxSYM cTnI micro-particle enzyme immuno-assay and qualitative cTnI with a Hexagon Troponin immuno-chromatographic one-step test. It did not prove possible to detect any significant association between pre- and post-dialysis cTnI levels. Comparison of results for serum and heparin plasma revealed no statistically significant difference between the level of cTnI and the mean values for plasma and serum with and without the addition of HBR. The cTnI concentrations in the samples without added HBR were lower than in those with HBR, but no statistically significant difference between the mean for cTnI and the mean of samples with and without added HBR was observed. During the study, 35.2% of the population died. A positive association was observed between the cTnI values in the patients still living and those patients who died from ischaemic cardiomyopathy (p = 0.039). The crude risk of death by cardiovascular disease was increased eight-fold (the 95% confidence interval being 1.2 to 51.1) in patients with a cTnI concentration greater than 0.04 ng/mL. Levels of cTnI may reflect occult myocardial ischemia and identify haemodialysis patients who face a greater risk of deat