Elevated concentrations of cardiac troponins are associated with severe coronary artery calcification in asymptomatic haemodialysis patients

Abstract

Background: Elevated concentrations of cardiac biomarkers, such as troponins and natriuretic peptides, have been shown to be predictive of poorer long-term cardiovascular outcomes in stable patients with end-stage renal disease (ESRD). However, little is known about the relationship between elevated concentrations of these cardiac markers and underlying coronary artery pathology in these patients. The aim of the present study was to investigate associations between coronary artery calcification (CAC) and the concentrations of cardiac biomarkers in ESRD patients.

Methods: We conducted a cross-sectional study of 38 asymptomatic patients (median age, 54 years; 26 males, 12 females; diabetic, 39%) who were undergoing chronic haemodialysis. In these patients, pre-dialysis circulating concentrations of cardiac troponin T (cTnT), cardiac troponin I (cTnI), creatine kinase-MB (CK-MB) and B-type natriuretic peptide (BNP) were measured. We quantified the level of CAC by multirow spiral computed tomography to obtain a CAC score. CAC scores > or = 400 were defined as being indicative of severe CAC.

Results: Severe CAC was detected in 17 patients (45%). The degree of CAC severity was positively associated (P < 0.05) with cTnT concentrations. Thus, 15% of patients had severe CAC in the lowest tertile of cTnT, 50% had severe CAC in the middle third, and 69% in the highest third. Similarly, the degree of severity of CAC was positively associated (P < 0.01) with cTnI concentrations across concentration categories. In contrast, there was no association between the degree of CAC severity and the concentrations of either BNP or CK-MB. A logistic regression analysis revealed that elevated concentrations of cTnT (> or = median vs <median, P < 0.05) and cTnI (> or = 0.1 ng/ml vs <detection limit, P < 0.05) were independently associated with severe CAC after adjusting for age, duration of dialysis, diabetes and previous cardiovascular events.

Conclusions: Elevated concentrations of cTnT and cTnI, but not BNP or CK-MB, were independently associated with the degree of severity of CAC in asymptomatic haemodialysis patients.