Abstract 2551: B-Type Natriuretic Peptide Levels at Greater Than One Year Post-Transplant Predict Graft Survival in Pediatric Heart Transplant Patients
Background: Data in adult heart transplant (HT) patients suggests that elevated B-type natriuretic peptide (BNP) levels predicts worse outcome. Minimal data on the utility of BNP levels exist in pediatric HT patients.
Objective: We tested the hypothesis that elevated BNP levels at > 1 year post-transplant are associated with worse overall graft survival.
Methods: Beginning in 2004, serial BNP levels were collected on all HT patients. Patients with BNP levels measured at > 1 year post-transplant were included, and the association of BNP levels with outcome was assessed.
Results: Seventy-seven patients (28 females) comprised the cohort. The median age at transplant was 4.7 years [interquartile range (IQR) 2.0 –11.3 years]. The median time post-transplant to the first BNP measurement was 1.8 years (IQR 1.1– 4.4 years), and the median number of BNP levels measured per patient was 10 (IQR 6 –14). Ten (13%) patients had graft loss over a median follow up time of 2.2 years (IQR 1.1–2.7 years). Eight (80%) had graft loss due to transplant coronary artery disease. The first BNP level measured was significantly higher in patients that went on to have graft failure, median 235 pg/ml (IQR 62–571 pg/ml), versus patients with graft survival, median 66 pg/ml (IQR 33–150 pg/ml) (p=0.02). Using Kaplan-Meier survival curves, patients with a first BNP level of > 200 pg/ml had significantly shorter time to graft loss compared to the rest of the cohort (p=0.009). When evaluating the trend in BNP levels over time, patients with graft failure had increasing levels, median BNP change of 257 pg/ml per year (IQR 66 – 620 pg/ml per year), versus patients with graft survival, median BNP change of (-) 57 pg/ml per year [IQR (-) 27 - (+) 7 pg/ml per year] (p<0.001). No patients whose BNP levels remained < 200 pg/ml for the duration of the study had graft loss while 30% of patients with a BNP > 200 pg/ml did lose their graft (p<0.001).
Conclusion: High or increasing BNP levels at > 1 year post-transplant are associated with worse graft survival in pediatric HT patients. Additional studies are needed to further define the prognostic role of BNP in this population.