RESUMO
BACKGROUND: Elevation of cardiac markers in patients with renal dysfunction has not been fully assessed reducing the diagnostic usefulness of these biomarkers. OBJECTIVE: To examine the effects of renal function and a medical record of cardiovascular disease on levels of cardiac biomarkers. METHODS: Serum samples were collected from 489 patients referred for GFR measurement using Cr51-EDTA or iohexol plasma clearance (measured GFR). The cardiac biomarkers Troponin T (hs-cTnT), Troponin I (hsTnI), N-Terminal pro-Brain Natriuretic Peptide (NTproBNP), Copeptin, Human Fatty Acid-Binding Protein (hFABP), as well as the kidney function biomarkers creatinine and cystatin C, were measured. Regression was used to analyse the relationship between biomarker levels and the glomerular filtration rate (GFR) between 15 and 90mL/min/1.73m(2). RESULTS: Compared with normal kidney function, the estimated increases in the studied cardiac biomarkers at a GFR of 15mL/min/1.73m(2) varied from 2-fold to 15-fold but were not very different between patients with or without a medical record of cardiovascular disease and were most prominent for cardiac biomarkers with low molecular weight. hs-cTnT levels correlated more strongly to measured GFR and increased more at low GFR compared to hs-cTnI. For hFABP and NTproBNP increases at low kidney function were more correctly predicted by a local Cystatin C-based eGFR formula compared with creatinine-based eGFR (using the MDRD or CKD-EPI equations). CONCLUSION: The extent of the elevation of cardiac markers at low renal function is highly variable. For hFABP and NTproBNP Cystatin C-based eGFR provides better predictions of the extent of elevation compared to the MDRD or CKD-EPI equations.