INTRODUCTION:  

Renal dysfunction (RD) at heart transplant (HTx) is widely recognized as a poor prognostic factor for survival and post-HTx renal function (RF). There is wide variability of practice in listing patients while depending on renal replacement therapy (RRT). We hypothesized that RD is most frequently pre-renal due to low cardiac output and tends to resolve after HTx. We sought to determine the outcome and long term RF of patients listed for HTx while on RRT.

METHODS:

This retrospective study included pediatric patients on RRT: (peritoneal dialysis, hemodialysis or hemofiltration) at time of listing for HTx between 2000 and 2014. Data was collected from medical charts and included: RRT pre and post-HTx, mechanical ventricular support pre- and post-HTx and potential risk factors such as ischemic time, donor-recipient size mismatch, HLA-sensitization, ABO-compatibility and concomitant morbidities.

We documented RF by measuring or estimating glomerular filtration rate (GFR) over time until October 2015. GFR was measured by radioisotope, estimated with CKiD formula when cystatin C was available, or Schwartz formula when only creatinine was available.

RESULTS:

12 patients required RRT at time of listing; 11 of which survived to HTx. The median age was 1.1 y ranging [0.01-14.8] at listing, 1.6 y [0.03-15.7] at HTx with a median waiting time of 40 days [1-342]. The primary cardiac diagnosis was congenital cardiopathy in 9/12, myocarditis, dilated cardiomyopathy and ischemic in the 3 others patients. Pre-HTx, they had RRT for a median time of 11 days [3-299]: 7 had continuous hemodialysis/filtration, 3 peritoneal dialysis and 2 both. 9 patients (82%) were on ECMO, 6 (54%) on VAD and 3 patients were highly sensitized prior to HTx (cPRA>50%).

Median post-HTx follow-up of this cohort was 6.4 y [3.3-8.8]. Actuarial post-HTx survival was 90% at 2 weeks, 73% at 1 month, 73% at 6 months, and 55% at 1 and 5 years. One patient was delisted and subsequently died. 4/5 patients died from cardiac failure and one from RD. 2 patients required ECMO for a mean duration of 19 days and one patient required VAD post-HTx. 8/11 patients required RRT for a median time of 17 days [0-240] post-HTx. All survivors were weaned off RRT and most recent mean GFR was 62±9 mL/min/1.73 m2; which represent mild renal dysfunction (CKD stage II).

CONCLUSION:

RD is associated with a high post-HTx mortality of 45% in our experience, however, death was mainly not due to RF. All survivors recovered RF with only mild impairment in the long-term follow-up. Dependency on RRT at the time of HTx assessment should not, as a sole factor, preclude patients from being listed.