Monthly reference change value of cardiac troponin in hemodialysis patients as a useful tool for long-term cardiovascular management

Abstract

Purpose of researchCirculating cardiac troponin (cTn) has been identified as a risk factor for cardiovascular and overall mortality in patients undergoing hemodialysis. However, its interpretation remains difficult due to the high prevalence of patients with cTn level beyond the 99th percentile. Determining the cTn reference change value (RCV) may help in assessing a clinically significant change of cTn during regular follow-up of patients. We aimed to determine the long-term RCV of cTn in such patients and to calculate the perdialytic reduction rate of cTn. Design and methodsTo calculate RCV, high-sensitivity (hs)-cTnT (Roche), hs-cTnI (Abbott), and cTnI-ultra (Siemens) were determined every month before the midweek dialysis session over a 3-month period in 36 stable hemodialysis patients. cTn was also measured after the midweek dialysis session to calculate the cTn removal rate. ResultsThe mean RCV (95% confidence interval) was 22% (18–26) for hs-cTnT versus 53% (34–73) for hs-cTnI versus 65% (45–84) for cTnI-ultra. Log-normal RCV (%) was −19/+25 for hs-cTnT, −33/+96 for hs-cTnI, and −39/+115 for cTnI-ultra. The index of individuality was <0.6 regardless of the cTn assay used. A significantly greater reduction rate was observed for hs-cTnT (48%) than for hs-cTnI (30%, p<0.001) and cTnI-ultra (29%, p<0.05). ConclusionsThese results underline the need to use the RCV approach rather than cutoff points to identify the critical change in long-term serial cTn levels. In addition, RCV should be determined for each available assay due to significant differences between assays. Removal of cTn during hemodialysis sessions should also be considered if acute coronary syndrome is suspected during a session.