The shortage of organs for heart transplantation has created a need to explore the use of extended-criteria organs. We report the preliminary use of normothermic TransMedics Organ Care System-an ex vivo approach to preserve extended-criteria brain-dead donor hearts. This System maintains a normal temperature, provides continuous perfusion and oxygenation, reduces ischemic time, and enables additional viability assessment options. In a retrospective single-centre study conducted from April 2020 to March 2023, four extended criteria brain-dead donor hearts were perfused and monitored using the Organ Care System. Suitability for transplantation was assessed based on stable or decreasing lactate levels, along with appropriate perfusion parameters. The Organ Care for use of the Organ Care System were coronary artery disease, left ventricular hypertrophy, high-dose inotrope use in the donor, a downtime exceeding 20 min, and a left ventricular ejection fraction of 40-50%. Three out of the four donor hearts were transplanted, while one was discarded due to rising lactate concentration. The three recipients had a higher surgical risk profile for heart transplant. All showed normal cardiac function and no primary graft dysfunction postoperatively. At 2-3 years post-transplant, all recipients have a ventricular function of >
60%, with only one showing evidence of mild rejection. The Organ Care System enables the successful transplantation of marginal donor organs in high-risk recipients, showcasing the feasibility of recruiting donors with extended criteria. This technique is safe and promising, expanding the donor pool and addressing the organ shortage in heart transplantation in Hong Kong.