Changes in estimated glomerular filtration rate over the first year following repeat heart transplant in children and young adults.

Background: Renal function is reduced in patients undergoing heart transplant due to hemodynamic compromise, cardiorenal syndrome, and nephrotoxin exposure. No current studies evaluate renal function in retransplants.

Methods: We reviewed all heart transplants at our center from 1995 to 2021 and matched first-time heart transplants with retransplants, based on age at transplant, sex, and race. Estimated glomerular filtration rate (eGFR) was derived from CKiD-U25 calculator using creatinine and measured prior to transplant, 1-week post-transplant, 1-3, 6, and 12 months post-transplant, and recent follow-up. Changes in eGFR were measured within and between patients using a piecewise linear mixed effect model with matching. Exploratory univariate analysis was performed to evaluate pre-transplant risk factors for decreased eGFR.

Results: The unmatched cohort included 393 heart transplant recipients, with 47 being retransplants. Thirty-eight patients in both groups with at least 1 year of follow-up underwent matching. Both retransplants and first-time transplants had an initial decline in eGFR. eGFR rebounded to baseline or above baseline at 1-3 months post-transplant, but eGFR in retransplants remained significantly lower. At 1-year post-transplant, the average eGFR was 67.8 ± 4.3 mL/min/1.73 m² versus 104.7 ± 4.3 mL/min/1.73 m² (p < .001) in the retransplants and first-time transplants group, respectively.

Conclusion: This study provides data on anticipated renal trajectory following retransplantation.