Background: Cardiac troponin T (cTnT) is a highly sensitive marker for the detection of myocardial damage. However, patients maintained on chronic dialysis often have increased serum cTnT concentrations without evidence of acute myocardial injury. The reason for this is unclear. In chronic haemodialysis patients, elevated plasma concentrations of big endothelin-1 (big ET-1) and endothelin-1 (ET-1) have been reported which may be associated with ischaemic heart disease. The aim of the present study was to investigate possible associations between cTnT, big ET-1, ET-1, other cardiac markers and cardiac disease in dialysis patients.
Methods: Thirty-six haemodialysis (HD) patients and 26 peritoneal dialysis (PD) patients without symptoms of acute myocardial ischaemia were investigated. In all patients, serum concentrations of cTnT (2nd generation ELISA), cardiac troponin I (TnI) (Opus, Behring), creatine kinase MB (CKMB) mass and creatine kinase (CK) were determined, in HD patients before and after dialysis. Additionally, in HD patients, plasma ET-1 and big ET-1 were measured. In 27 HD patients, left ventricular mass index (LVMI) was determined. Patients with ischaemic heart disease (IHD) were compared with non-IHD patients.
Results: Serum cTnT was elevated (> or =0.10 microg/l) in 20 of 36 HD patients and in eight of 26 PD patients. cTnI was elevated (> or =0.5 microg/l) in four of 62 dialysis patients. HD+PD patients with IHD showed higher cTnT than HD+PD patients without IHD, and ET-1 concentrations were higher in HD patients with than without IHD. In HD patients, there was a positive correlation between cTnT and big ET-1. In HD patients with left ventricular hypertrophy (LVH), serum cTnT, CKMB mass and post-dialysis plasma big ET-1 were higher than in patients with normal LVMI. Furthermore there was a positive correlation between cTnT levels and LVMI.
Conclusion: These findings suggest that circulating cTnT may reflect left ventricular hypertrophy and/or myocardial ischaemia in dialysis patients, and indicate that ET-1 and big ET-1 might be associated with these conditions.