troponin-i is not falsely elevated in asymptomatic dialysis patients

Abstract

Dialysis patients with troponin-I levels above the cut-off value diagnostic for acute myocardial event (AME) are sometimes labeled as having "renal cause" of elevated troponin-I. Patients with troponin-I levels above 0.0 ng/mL, but below the cut-off level for an AME, are reported to have increased risk for coronary heart disease and mortality. Single pre-dialysis blood samples were taken from 150 asymptomatic dialysis patients (on hemo- or peritoneal dialysis) for troponin-I, cardiac enzymes, C-reactive protein (CRP) and lipid parameters. Troponin-I was measured by a chemiluminescent microparticle immunoassay (CMIA), of which the cut-off value for AME was set at ≥0.4 ng/mL. Patients with troponin-I levels of 0.0 ng/mL, and those with levels between 0.1 and 0.3 ng/mL, were compared regarding their cardiovascular risk profile. None of the patients had troponin-I concentrations above the cut-off level diagnostic for an AME, with 85.3% of the patients having levels of 0.0 ng/mL. While there was no difference in the "traditional" risk factors such as age, body mass index, prevalence of diabetes mellitus, hypertension, total cholesterol and low-density lipoprotein cholesterol between patients with troponin-I levels of 0.1-0.3 ng/mL and those with levels of 0.0 ng/mL, CRP concentrations were higher in the former. In peritoneal dialysis patients, the weekly Kt/V was lower in the patients with troponin levels between 0.1 and 0.3 ng/mL. The findings should add strong support in settling the debate of whether or not in patients on dialysis, falsely elevated levels of troponin-I "commonly" occur. An increased level of CRP and lower Kt/V might add to the cardiovascular risk in patients with troponin-levels between 0.1 and 0.3 ng/mL.