Long-term outcomes of simultaneous heart and kidney transplantation in pediatric recipients

Kidney transplant outcomes in children with simultaneous versus sequential heart-kidney transplants

BACKGROUND

Heart transplant recipients frequently require kidney transplantation for concomitant advanced chronic kidney disease. Data on simultaneous (heart and kidney transplants performed simultaneously) versus sequential (heart transplant performed before kidney) heart-kidney transplants in children are limited. Herein, we compare kidney transplant outcomes between the two groups.

METHOD

We used the Scientific Registry of Transplant Recipients to identify all pediatric (age <21 years) heart transplant recipients who also received a kidney transplant within 10 years of the heart transplant. We divided the study cohort into simultaneous heart-kidney and sequential heart-kidney recipients. We compared patient and death-censored graft survival using the Cox regression, adjusting for age at kidney transplant, sex, race, pre-transplant dialysis, donor type, and prior kidney transplant. We evaluated delayed graft function (defined as dialysis within the first week posttransplant) using logistic regression.

RESULTS

Our analysis cohort included 165 recipients (86 simultaneous and 79 sequential). The incidence of delayed graft function was higher in simultaneous recipients (22.4 vs. 7.7%, p=0.017), but the difference lost statistical significance on multivariable analysis. We found no difference in patient survival (aHR 0.97; 95% CI 0.39, 2.41; p=0.95) after kidney transplant but higher death-censored kidney graft survival in sequential heart-kidney recipients compared with simultaneous heart-kidney recipients (aHR 4.26; 95% CI 1.21, 14.9; p=0.02).

CONCLUSION

Sequential heart-kidney transplants are associated with higher death-censored kidney allograft survival in children compared with simultaneous heart-kidney transplants.

Heart-kidney listing is better than isolated heart listing for pediatric heart transplant candidates with significant renal insufficiency

OBJECTIVES

Significant renal insufficiency is identified as a risk factor for post-transplantation mortality in pediatric heart transplant recipients. This study evaluates simultaneous heart-kidney transplantation listing outcomes compared with heart transplant for pediatric candidates with significant renal insufficiency.

METHODS

The United Network for Organ Sharing registry was searched for patients (January 1987 to March 2020) who were simultaneously listed for a heart-kidney transplantation or for heart transplant with significant renal insufficiency at the time of listing. Significant renal insufficiency was defined as needing dialysis or having a low estimated glomerular filtration rate (<40 mL/min). Survival was calculated using Kaplan-Meier analysis.

RESULTS

A total of 427 cases were identified; 109 were listed for heart-kidney transplantation, and 318 were listed for heart transplant alone. Median time on the waitlist was 101 days (interquartile range, 28-238) for heart-kidney transplantation listings compared with 39 days (14-86) and 23.5 days (6-51) for heart transplant recipients with a low estimated glomerular filtration rate (P = .002) or on dialysis (P < .001), respectively. Of all heart-kidney transplantation listings, 66% (n = 71) received a transplant compared with 54% (n = 173) of heart transplantation with significant renal insufficiency (P = .005) with a mean survival of 14.6 years (12.7-16.4 years) for heart transplant without significant renal insufficiency at transplantation and 7.6 years (5.4-9.9 years) for heart transplant with significant renal insufficiency at transplantation. At 1 year after listing, 69% of heart-kidney transplantation listed recipients were alive, compared with 51% of heart transplant listed recipients (P = .029). Heart-kidney transplantation recipients had better 1-year post-transplantation survival (86%) than heart transplantation with significant renal insufficiency at transplant (66%) (P = .001). There was no significant difference in the 1- and 5-year survivals of those undergoing heart transplantation listed with significant renal insufficiency but no significant renal insufficiency at the time of transplant (89% and 78%) and heart-kidney transplantation recipients (86% and 81%; P = .436).

CONCLUSIONS

Pediatric candidates with significant renal insufficiency listed for heart-kidney transplantation have superior waitlist and post-transplantation outcomes compared with those listed for heart transplant alone. Patients with significant renal insufficiency should be listed for heart-kidney transplantation, however; if their renal function improves significantly, heart transplant alone appears judicious.

Simultaneous pediatric heart-kidney transplant outcomes in the US: A-25 year National Cohort Study

BACKGROUND

Pediatric sHKTx remains uncommon in the US. We examined outcomes of pediatric sHKTx compared to PHTx alone. Our objective was to identify a threshold eGFR that justified pediatric sHKTx.

METHODS

Data from the SRTR heart and kidney databases were used to identify 9245 PHTx, and 63 pediatric sHKTx performed between 1992 and 2017 (age ≤21 years).

RESULTS

The median age for sHKTx was 16 years, and included 31 males (31/63 = 49%). Over half of sHKTx (36/63 = 57%) were performed in cases where pretransplant dialysis was initiated. Among patients who required pretransplant dialysis, the risk of death in sHKTx recipients was significantly lower than PHTx alone (sHKTx vs. PHTx: HR 0.4, 95% CI [0.2, 0.9], p = .01). In those without pretransplant dialysis, there was no improvement in survival between sHKTx and PHTx (p = .2). When stratified by eGFR, PHTx alone recipients had worse survival than sHKTx in the group with eGFR ≤35 ml/min/1.73 m² (p = .04). The 1- and 5-year actuarial survival rates in pediatric sHKTx recipients were 87% and 81.5% respectively and was similar to isolated PHTx (p = .5). One-year rates of treated heart (11%) and kidney (7.9%) rejection were similar in sHKTx compared to PHTx alone (p = .7) and pediatric kidney transplant alone (p = .5) respectively.

CONCLUSION

Pediatric sHKTx should be considered in HTx candidates with kidney failure requiring dialysis or eGFR ≤35 ml/min/1.73 m² . The utility of sHKTx in cases of kidney failure not requiring dialysis warrants further study.