[B-type natriuretic peptide assessment in the diagnosis of rejection after pediatric heart transplant].

BACKGROUND Rejection is one of the major causes of mortality following pediatric heart transplant. B-type natriuretic peptide (BNP) has been studied as a method for the diagnosis of acute rejection, especially in adult patients undergoing heart transplant. OBJECTIVE To correlate serum BNP levels with acute rejection as diagnosed by endomyocardial biopsy in patients of the pediatric heart transplant group. METHODS A total of 50 BNP samples were collected from 33 children in the postoperative period of heart transplant, and data on age, gender, skin color, blood group, immune panel, follow-up time after transplant, functional class, immunosuppressive regimen used and number of rejections were analyzed. RESULTS Thirty three children with median age of 10.13 years were analyzed; of these, 54% were females and 78% were Caucasians. BNP levels were determined at a mean time from transplant of 4.25 years. Nine episodes of rejection were diagnosed in eight patients (27%) by means of endomyocardial biopsy; of these, three were grade 3A, five were grade 2, and one had humoral rejection. At the moment of biopsy, most patients were asymptomatic. The mean serum BNP level was 77.18 pg/ml, with 144.22 pg/ml in the group with rejection and 62.46 pg/ml in the group without rejection, with p = 0.02. CONCLUSION Asymptomatic children can present acute rejection in the postoperative period of heart transplant. Serum BNP levels show a statistically significant difference in the group with rejection and thus can be an additional method in the diagnosis of cardiac rejection.