Post-Transplant Trends in BNP Levels among Recipients of Heart versus Heart-Kidney Transplantation

Purpose Circulating levels of b-type natriuretic peptide (BNP) are elevated following heart transplantation (HT), peak at 1-2 months post-HT, and decline over the course of several months but rarely return to normal. We sought to determine the time course of BNP level following combined heart-kidney transplantation (HKT) compared to HT alone. Methods Between July, 2014 and August, 2017, 11 patients underwent HKT; they were matched based on age, gender, race and body mass index (BMI) to 22 patients undergoing isolated HT. Baseline demographics, serial BNP levels, and estimated glomerular filtration rate (eGFR; ml/min/1.73 m2) were monitored in patients at post-transplant days 30, 60, 90, 180 and 365. Wilcoxon rank-sum test was used to compared median BNP levels at different time points between the groups. Results Average age of HKT recipients was 54±18 years (82% females, 27% black Americans, BMI 25±5 kg/m2) and that of HT recipients was 55±14 years (82% females, 27% black Americans, BMI 26±3 kg/m2). As shown in the Figure, BNP values decreased significantly among HKT recipients by 90-days, and remained significantly lower at 1-year post-transplantation (p<0.05). In all but two HKT recipients, BNP levels fell below 100 pg/mL within 90 days. Conclusion Unlike HT alone, BNP levels were found to be near normal in the majority of HKT recipients within a much shorter period of time and remained low up to 1-year post-transplant. This finding can potentially be explained by improved renal function with kidney transplant; although, the effect of KT on lusitropic properties of transplanted heart cannot be ruled out. Circulating levels of b-type natriuretic peptide (BNP) are elevated following heart transplantation (HT), peak at 1-2 months post-HT, and decline over the course of several months but rarely return to normal. We sought to determine the time course of BNP level following combined heart-kidney transplantation (HKT) compared to HT alone. Between July, 2014 and August, 2017, 11 patients underwent HKT; they were matched based on age, gender, race and body mass index (BMI) to 22 patients undergoing isolated HT. Baseline demographics, serial BNP levels, and estimated glomerular filtration rate (eGFR; ml/min/1.73 m2) were monitored in patients at post-transplant days 30, 60, 90, 180 and 365. Wilcoxon rank-sum test was used to compared median BNP levels at different time points between the groups. Average age of HKT recipients was 54±18 years (82% females, 27% black Americans, BMI 25±5 kg/m2) and that of HT recipients was 55±14 years (82% females, 27% black Americans, BMI 26±3 kg/m2). As shown in the Figure, BNP values decreased significantly among HKT recipients by 90-days, and remained significantly lower at 1-year post-transplantation (p<0.05). In all but two HKT recipients, BNP levels fell below 100 pg/mL within 90 days. Unlike HT alone, BNP levels were found to be near normal in the majority of HKT recipients within a much shorter period of time and remained low up to 1-year post-transplant. This finding can potentially be explained by improved renal function with kidney transplant; although, the effect of KT on lusitropic properties of transplanted heart cannot be ruled out.