Determinants and prognostic significance of an intra-dialysis rise of cardiac troponin I measured by sensitive assay in hemodialysis patients.

BACKGROUND: Previous studies using conventional cTnI assays reported conflicting results on the evolution of cTnI levels during hemodialysis. The determinants and prognostic significance of changes in cTnI during hemodialysis are presently unknown. The aim of this prospective study was to characterize the determinants and prognostic significance of intra-dialysis changes in cTnI using a sensitive assay.
METHODS: cTnI was measured before and after hemodialysis with a sensitive assay in 90 chronic patients without acute cardiac symptoms. Multivariable regression analyses were used to identify factors that were associated with intra-dialysis rise in cTnI. The prognostic effect of an intra-dialysis rise in cTnI during a 52-month follow-up was evaluated using Cox regression models. The primary and secondary endpoint was the incidence of major adverse cardiovascular events and all-cause mortality, respectively.
RESULTS: Pre-dialysis cTnI was elevated in 31 patients (34 %). cTnI increased significantly during dialysis and this had a trend to be associated with longer dialysis vintage. A greater intra-dialysis rise in cTnI was associated with a significantly higher incidence of cardiovascular events, also after correction for age, gender, dialysis vintage, residual diuresis, previous cardiovascular events, and pre-dialysis cTnI levels (HR per 10 ng/L rise in cTnI: 1.21; CI 1.06-1.38; p 0.005).
CONCLUSION: TnI levels rise significantly during hemodialysis and a greater intra-dialysis rise in cTnI is associated with an increased incidence of cardiovascular events. These findings suggest that hemodialysis has an acute deleterious effect on the heart. An intra-dialysis rise in cTnI may help identify patients who are susceptible to the hemodynamic stress of hemodialysis.