Don't Go Breaking My Heart! Variability of Troponin I Levels in Patients on Long-Term Haemodialysis over Years

Background: Patients undergoing chronic haemodialysis (HD) have remarkably higher risk for major adverse cardiovascular events. Haemodynamic and volume changes inbetween dialysis sessions lead to constant cardiac burdain and strain which could increase cardiac troponin levels without signs and symptoms of an acute coronary syndrome (ACS). This makes it difficult to diagnose acute disorders. Primary goal was to evaluate the basal troponin values of HD patients on their first weekly treatment (the highest volume overload) and observe its oscillations over two years. Our previous trials showed the weekly coefficient of variability (CV) of 20% and 31% for troponin in HD patients (over one week and one year). Methods: Data of 46 patients (14 female, 32 male) undergoing chronic HD programme at Dubrava University Hospital were collected after aquiring informed consent. Troponin levels were measured 8 times during the period of 2 years (every 3 months) while collecting regular monthly tests, using Beckman Coulter High-Sensitivity Troponin I (hs-cTnI) assay - before the first session that week. The upper reference limit (URI) for hs-cTnI is <14.9 ng/L and <19.8 ng/L for female and male patients. Results: The mean hs-cTnI per monthly measurement were in the range from 20,92 ng/L to 29 ng/L, with the mean value of every measurement 24,6 ng/L. Almost all the female patients (93%) and 50% of male patients had elevated hs-cTnI values (63% altogether). The mean values were higher in male patients (25,1,4 ng/L) than in female patients (23,3 ng/L). Comparing patients on HD and haemodiafiltration (HDF) the average troponine values were 22,8 ng/L and 27,2 ng/L respectively. The coefficient of variation (CV) was measured for each patient and the mean CV for hs-cTnI values was 40,5% (7% - 170%) with difference between female (33%) and male (44%) patients, and between HD (37%) and HDF (47%) patients. Conclusion: Our results show that hs-cTnI values were elevated in 63% of patients on HD without signs of ACS. During two years hs-cTnI values had variability of 41% (higher than during one year previously measured -31%). The variability was lower in female patients (33%) and in patients on HD (37%). The patient's hs-cTnI mean value could be taken as a personal basal value for comparison when diagnosing ACS. Funding: Government Support – Non-U.S.