OPtimal Adult Heart Transplant Immunosuppression With MicroRNA Levels

Inclusion Criteria: * Age ≥ 18 years at enrollment * Receipt of orthotopic heart transplant (OHT) within the prior 1 month ± 2 weeks * Planned follow-up at the transplant center for a minimum of one-year. * Patient able and willing to comply with the study visit schedule, study procedures, and study requirements. Exclusion Criteria: * Recipient of a multi-organ transplant * History of prior solid organ transplant before the index heart transplant * Ongoing mechanical circulatory support or hemodynamic instability (e.g., inotrope or vasopressor therapy) * Ongoing need for renal replacement therapy and/or dialysis * Active infection requiring either a) hospitalization b) treatment with antimicrobial therapy or c) reduction in immunosuppression * Active rejection being treated with intravenous medications or plasmapheresis