Clinical utility of NT-proBNP levels in late heart transplantation patients

BackgroundThe present work was aimed to describe NT-proBNP levels in heart transplant patients after the first year postsurgery.MethodsNT-proBNP concentration was measured in 1231 samples from 142 patients when a routine four-month follow-up was carried out, including other biochemical and clinical examinations. Endomyocardial biopsies were performed only upon clinical suspicion of acute rejection.ResultsNT-proBNP concentrations were not significantly correlated to post-transplantation time, though differences were observed according to clinical symptoms (Kruskal–Wallis test, p < 0.001). Although multivariate analysis revealed statistically significant association between NT-proBNP concentration and some qualitative (cardiac allograft vasculopathy-CAV-, sex, diabetes) and quantitative (creatinine, hematocrit, age) variables, only moderately relevant contribution was observed for creatinine and CAV. Patients with rejection showed noticeable increases in serum NT-proBNP concentrations, above more than 2.5 times the reference change value (97%). NT-proBNP concentrations higher than 1000 ng/L increased in 3.5 times (95%CI: 2.4–5) the risk of death in less than one year.ConclusionsAfter the first year from surgery, NT-proBNP concentrations were not associated to post-transplantation time and NT-proBNP could be a useful diagnostic marker for rejection, whenever serial measurements are made. A NT-proBNP cutoff value of 1000 ng/L was identified for classifying patients at risk of death after one year.