This retrospective study evaluated the effectiveness of two cardiac preservation solutions, HTK-Custodiol and St. Thomas, used in adult heart transplantations at the University Hospital of Lausanne. The study compared outcomes such as hospital mortality, midterm survival, inotropic score, primary graft dysfunction, and rejection score between 154 patients from 2009 to 2020. Results indicated that HTK-Custodiol significantly improved postoperative outcomes, including lower inotropic and rejection scores, reduced 30-day mortality, and enhanced midterm survival compared to the St. Thomas solution.