Background: Cardiac disease is the main cause of mortality in long-term hemodialysis patients. Cardiac troponins (cTn) have been proposed to be markers of cardiac damage, but their value is still debated in hemodialysis patients. The aim of this prospective study is to assess the prognostic value of biochemical cardiac markers in long-term hemodialysis patients.
Methods: We measured serum levels of cTn I (cTnI), cTn T (cTnT), and creatine kinase-MB (CK-MB) in 258 asymptomatic patients (mean age, 60 +/- 15 years; 150 men) before the dialysis treatment. All causes of death and major adverse cardiac events (MACEs: cardiac death, myocardial infarction, or unstable angina) were recorded at 1 and 2 years of follow-up. A Cox proportional hazard regression model was used to identify factors predictive of mortality.
Results: On inclusion, 48 patients (18.6%) had cTnT levels greater than 0.1 ng/mL, 46 patients (17.8%) had cTnI levels greater than 0.15 ng/mL, and 18 patients (7.0%) had CK-MB levels greater than 3 ng/mL. Of 246 patients followed up at 2 years, 64 patients (26%) had died, including 29 patients (11.8%) of cardiac disease, and 49 patients (19.9%) experienced at least 1 MACE. MACEs were significantly greater for patients with elevated predialysis serum cTnT and CK-MB levels (>0.1 ng/mL and 3 ng/mL, respectively) than for patients with normal levels of these cardiac markers (31.9% versus 17.1%; P = 0.01; 38.9% versus 18.4%; P = 0.02, respectively). No differences were found for cTnI levels. In multivariate analysis, age (relative risk [RR], 1.04; P = 0.002), previous ischemic heart disease (RR, 2.5; P = 0.0001), and serum cTnT levels greater than 0.1 ng/mL (RR, 1.9; P = 0.04) were independent significant factors for MACEs.
Conclusion: Increased predialysis serum levels of cTnT and CK-MB, but not cTnI, were predictive of a high risk for overall mortality and MACEs at 2 years in asymptomatic hemodialysis patients.