Aim of the study: Use OCT imaging for identification of patients with early rapid progression of CAV (rapid progressors) and to identify the critical risk factors responsible for CAV progression. The impact of conventional and heart transplant (HTx) specific risk factors, such as donor-specific antibodies or rapid heart rate will be studied in a prospective, national-level cohort study. The implication of OCT results will lead to adjustment of immunosuppressive therapy in one year after heart transplant to prevent further progression of the disease in CAV rapid progressors.