This study will analyze extracellular vesicle (EV)-derived protein profiles in heart transplantated patients during the first 15 months post-transplantation to investigate, if there are distinct EV-derived proteins or protein patterns that allow early and reliable diagnosis of acute cardiac allograft rejection. Additionally, it will explore temporal changes in the EV-derived protein profile during the early postoperative period irrespective of acute allograft rejection, and will investigate, if there are correlations between EV protein markers and imaging findings.

Inclusion Criteria:

• Subject is either on the heart transplant waiting list or is still hospitalised following HTx surgery.

• Age of subject is ≥ 18 years.

• Subject is female or male.

• Capacity to consent.

• Signed written informed consent.

• For female subjects:

  1. Confirmed post-menopausal state, defined as amenorrhea for at least 12 months, or
  2. If being of childbearing potential: Negative highly sensitive urine or serum pregnancy test before inclusion.

Exclusion Criteria:

• Concurrent multiple solid organ or tissue transplants.
• Prior history of any organ or cellular transplantation.
• Subject suffers from an addiction or from a disease that prevents the subject from recognising nature, scope, and consequences of the study.
• Subject shows an inability to comply with all the study procedures and follow-up visits.
• Subject is legally detained in an official institution.
• Subjects who are unwilling to consent to saving and propagation of pseudonymised medical data for study reasons.
• Subject is financially dependent on the investigators or the study site.

Patients within the first year after heart transplantation