Bridge to simultaneous heart-kidney transplantation via extracorporeal life support: National outcomes in the new heart allocation policy era.

Background: Since United Network for Organ Sharing (UNOS) revised their heart allocation policy in 2018, usage of veno-arterial extracorporeal life support (VA-ECLS) has dramatically increased as a bridge to transplant. This study investigated outcomes of VA-ECLS patients bridged to simultaneous heart-kidney transplant (SHK) in the new policy era.

Methods: This study included 774 adult patients from the UNOS database who received SHK between 10/18/18 and 12/31/21 and compared patients bridged to transplant on VA-ECLS (n = 50) with those not bridged (n = 724).

Results: At baseline, SHK recipients bridged from VA-ECLS were younger (50.5 vs 58.0 years, p = 0.007), had higher estimated glomerular filtration rate (eGFR) at time of transplant (47.6 vs 30.1, p < 0.001), and spent fewer days on the waitlist (7.0 vs 33.5 days, p < 0.001). In the perioperative period, VA-ECLS was associated with higher rates of temporary dialysis (56.0% vs 28.0%, p < 0.001) but similar 2-year cumulative incidence of chronic dialysis (7.5% vs 5.4%, p = 0.800) and renal allograft failure (12.0% vs 8.1%, p = 0.500) compared to non-ECLS cohort. However, VA-ECLS patients had decreased survival to discharge (76.0% vs 92.7%, p < 0.001) and 2-year post-transplant survival (71.7% vs 83.0%, p = 0.004), as well as greater 2-year cumulative incidence of cardiac allograft failure (10.0% vs 2.7%, p = 0.002). Multivariable analyses found VA-ECLS at time of transplant to be independently associated with 2-year post-transplant mortality (HR [95% CI]: 3.40 [1.66-6.96], p = 0.001) and cardiac allograft failure (sub-distribution hazard ratio [SHR] [95% CI]: 8.51 [2.77-26.09], p < 0.001).

Conclusion: Under the new allocation policy, patients bridged to SHK from VA-ECLS displayed greater early mortality and cardiac allograft failure but similar renal outcomes compared to non-ECLS counterparts.