Patients presenting for heart/kidney transplantation who consent to participate will be enrolled in this prospective, open-label, single-arm trial to undergo heart transplantation with planned delayed kidney transplantation with machine perfusion of the kidney allograft. Kidneys will be preserved using hypothermic oxygenated machine perfusion (HOPE) prior to transplantation. Timing of kidney implantation will be determined by recipient stability (e.g., vasopressor and inotrope requirements, coagulopathy, heart graft function) and allow for at least 6 hours of HOPE preservation. Both heart and kidney transplant procedures will follow standard of care techniques.

During combined heart and kidney transplantation, heart and kidney allografts may be implanted during a single operative event, or with delayed kidney implantation in a second operative event. Timing of the delay is often determined by recipient stability and kidney availability; however, clinicians must balance recipient factors with accumulating cold ischemic time of the kidney allograft. This study uses hypothermic oxygenated machine perfusion to reduce ischemic injury to the kidney allograft and allow for improved recipient stability with planned delayed implantation of the kidney graft. Delays will allow for at least 6 hours of hypothermic oxygenated machine perfusion prior to implantation.

Delayed graft function (DGF) of the kidney allograft is defined as dialysis within the first 7 days post-transplant and will be monitored for all participants.

Safety endpoint will be assessed by monitoring for adverse events associated with either heart or kidney allografts within 90-days of initial operative event. Adverse events may include graft primary non-function, wound infection, urinary tract infection, ventilator-associated pneumonia, return to operating room, etc. Complications will be reported by Clavien-Dindo classification and analyzed as both those relating directly to the kidney transplant as well as overall incidence.

Primary graft dysfunciton (PGD) of the heart allograft after transplant is defined as left ventricle, right ventricle, or biventricular dysfunction that occurs within 24 hours after surgery and is not associated with a discernible cause such as hyperacute rejection, pulmonary hypertension, massive blood product transfusion during surgery, or prolonged graft ischemic time. Grading will be done according to International Society of Heart and Lung Transplantation guidelines.