Donor Derived Cell Free DNA (Dd-cfDNA) as a Biomarker for Allograft Rejection in Heart Transplant Recipients

Following heart transplantation (HTx), lifelong immunosuppressive treatment is required to prevent the immune system from attacking, damaging, and rejecting the donor hear (allograft). Currently, diagnosis of allograft rejection is based on evaluation of endomyocardial biopsies (EMB), which remains the gold standard for rejection diagnostics. However, previous research have highlighted limitations of EMBs, including interrater variation, sampling error and risks of complications. Donor-derived cell-free DNA (dd-cfDNA) has emerged as a promising post-transplant biomarker of allograft rejection. Nevertheless, evidence suggests that dd-cfDNA demonstrates greater diagnostic performance for antibody-mediated rejection (AMR) than for cellular rejection (TCR) and that the specificity exceeds its sensitivity in predicting rejection, highlighting limitations in its clinical application. The primary objective of this observational project are to investigate if measurement of dd-cfDNA can be utilized as a biomarker for acute rejection in the management of heart transplant recipients during the first year after transplantation in a Danish-Norwegian patient cohort. Secondary objectives include: * to correlate dd-cfDNA levels with markers of allograft dysfunction and rejection, i.e., EMBs, ejection fraction, left ventricular global longitudinal strain, troponin T, natriuretic peptide test (proBNP) and score of cardiac allograft vasculopathy (CAV) * to examine post-transplant dd-cfDNA kinetics during the first 6 six weeks after HTx * to explore clinical meaningful change in dd-cfDNA associated with acute allograft rejection * to investigate the association between dd-cfDNA, chronic allograft rejection, allograft dysfunction and patients' long-term survival To study the objectives, this project will include 100 HTx patients prior to transplantation over a 2-3 year period and conduct a long-time follow up 10 years after transplantation. Patients entering the waiting list for HTx at Rigshospitalet Copenhagen, Denmark, Oslo University Hospital, Rikshospitalet Oslo, Norway, or Aarhus University Hospital, Denmark, are invited to participate in the project. Patients are invited to participate in the current project if fulfilling the pre-defined inclusion criteria and no exclusion criteria. A comprehensive collection of clinical, pathological and immunological data is conducted from up to 15 visits during the first year after transplantation. Thereafter, from all annual visits and upon admission if allograft rejection is suspected.

Inclusion Criteria: * Patients entering the waiting list for their first heart transplantation (HTX1) at Rigshospitalet Copenhagen, Denmark, Rikshospitalet Oslo, Norway, or Aarhus University Hospital, Denmark * Patients ≥18 years old * Patients signing informed consent Exclusion Criteria: * Patients who are withdrawn from the heart transplant waiting list after informed consent has been provided * Patients who have previously received a solid organ transplantation * Patients unable to receive and understand the oral and written project information