High Rate of Kidney Graft Failure after Simultaneous Heart-Kidney Transplantation.

Abstract

The indications and outcomes of Simultaneous heart-kidney transplantation (SHKT) remain sub-optimally defined. Risk factors for renal graft failure after SHKT also remain poorly defined. We analyzed the renal graft outcomes among SHKT recipients using United Network for Organ Sharing database from 2015-2020. To evaluate for factors associated with poor renal outcomes, we compared SHKT and kidney transplantation alone (KTA) recipients using propensity score matching. Among SHKT recipients, rate of primary non-function (PNF) of kidney graft was 3%, 30-day kidney graft failure rate was 7.0%, and the 30-day post-transplant mortality rate was 4.1%. The incidence of delayed kidney graft function (KDGF) was 27.5%. Kidney graft failure was seen early post-SHKT with most common causes of patient death (43.9%) and PNF of kidney graft (41.5%). One-year and two-year patient survival was 89.2% and 86.5%, and one-year and two-year freedom from kidney graft failure was 85.4% and 82.7%, respectively. In subgroup analysis of SHKT recipients, use of pre-transplant mechanical cardiac support (adjusted Odds Ratio (aOR) 2.57, P=0.017), higher cPRA (aOR 1.76, P=0.016), and older donor age per 10 years (aOR 1.94, P=0.001) were associated with PNF. Pre-transplant extracorporeal membrane oxygenation support was associated with the increased risk of 30-day recipient mortality (aOR 5.55, P=0.002). Increased 30-day graft failure was seen in SHKT recipients with pre-transplant mechanical cardiac support (aOR 1.77, P=0.038) and dialysis at time of transplant (aOR 1.72, P=0.044). Multivariable Cox-Hazard analysis demonstrated that SHKT, when compared to KTA, is associated with increased kidney graft failure (Hazard Ratio, 2.56, P<0.001) and recipient mortality (Hazard Ratio: 2.65, P<0.001). SHKT is associated with high rates of kidney graft failure. Identification of risk factors for renal graft failure can help optimize recipient selection for SHKT vs Kidney after HT, especially after introduction of the new safety-net policy.