Predictive value of brain natriuretic peptide in the diagnosis of heart transplant rejection

Aim: To evaluate the pattern of brain natriuretic peptide (BNP) concentration in heart transplant (HT) recipients and its relation to the degree of graft rejection determined by endomyocardial biopsy specimen. Methods: We studied 71 consecutive HT recipients (62 men, 53 +/- 11 years). The patients underwent 383 biopsies. Creatinine and BNP concentrations and hemodynamic parameters were determined along with the degree of graft rejection using endomyocardial biopsy specimens. We considered treatable rejection as International Society for Heart and Lung Transplantation Grade greater than or equal to2 in the first 90 days and greater than or equal to3A thereafter. We included a control group of 36 healthy individuals. Results: Brain natriuretic peptide concentration was significantly greater among HT recipients (264 +/- 318 pg/ml) than in controls (17 +/- 16 pg/ml). In the first 90 days, BNP concentration was significantly greater among the patients with graft rejection (510 +/- 470, n = 84, vs 278 +/- 255, n = 87; p < 0.0001), although the corresponding discriminatory capacity was small. After the first 90 days, BNP values were similar in patients with and without graft rejection (170 +/- 297, n = 17, vs 142 +/- 203, n = 195; p = not significant). Creatinine concentration increased with time after transplantation and did not correlate with BNP concentration. We observed significant positive correlation between BNP concentration and hemodynamic parameters. Conclusions: Brain natriuretic peptide concentration remains increased after HT, with stabilization after the 4th month. Brain natriuretic peptide concentrations are slightly greater among patients with treatable rejection, particularly in the first 90 days, although BNP concentration lacks discriminatory capacity to serve as a guide to performing biopsy.