Post-Operative Acute Kidney Injury After Pediatric Heart Transplantation and Longitudinal Invasive Assessment of Cardiac Filling Pressures.

Background

Acute kidney injury (AKI) has been associated with diastolic dysfunction in pre-clinical studies, but with limited evaluation in clinical settings. We sought to examine the association between post-operative AKI and diastolic function after pediatric heart transplantation.

Methods

We conducted a single-center retrospective review of patients ≤ 21years undergoing first-time heart transplantation between May 2010-July 2023. AKI was defined and staged per the KDIGO creatinine criteria, with Stage 2 or 3 classified as severe. Right ventricular end-diastolic pressure (RVEDP) and pulmonary capillary wedge pressure (PCWP) obtained from surveillance cardiac catheterizations in the first two years post-transplant were used to assess diastolic function. Linear mixed-effects models were used to compare hemodynamics between groups.

Results

We included 101 patients, aged 0-20 years, median 4 years (IQR 0-13). Pre-transplant diagnosis was congenital heart disease (CHD) in 51 (50%) and cardiomyopathy in 50 (50%) patients. Post-operative AKI occurred in 29 (29%) patients; 16/29 had severe AKI. AKI was more common in patients with CHD than cardiomyopathy [20/29 (69%) vs. 9/29 (31%), p = 0.02]. On mixed-effects model analysis adjusting for pre-transplant diagnosis, ischemia time > 4 h, and time since transplantation, severe AKI was associated with higher filling pressures over the first 2 years post-transplant, including a 2.2 mmHg increase in RVEDP (95% CI 1.3-3.1; p < 0.0001) and a 1.8 mmHg increase in PCWP (95% CI 0.8-2.8; p = 0.0005).

Conclusions

Severe post-transplant AKI was independently associated with higher biventricular filling pressures, suggesting a clinically relevant kidney-heart interaction. Larger studies are needed to further define its mechanistic and clinical implications.