IMR-Heart Trasplant Study

Acute allograft rejection (AAR) is an important cause of morbi-mortality in heart transplant (HT) patients, particularly during the first year. Endomyocardial biopsy (EMB) is the "gold standard" to guide post- heart transplantation treatment. However, it is associated with complications that can be potentially serious. The index of microvascular resistance (IMR) is a specific physiological parameter used to assess microvascular function. Invasive coronary assessment has been shown to be both feasible and safe. Detection of coronary microvascular dysfunction (MCD) by IMR may help to identify high risk HT patients. In fact, an increased IMR measured early after HT has been associated with AAR, higher all-cause mortality and adverse cardiac events. A high IMR value early after HT may identify patients at higher risk who require increased surveillance or adjustments in immunosuppressive therapy. Conversely, a low IMR value may support reducing the number of EMBs. Our aim is to evaluate IMR in heart transplant patients within the first year. Changes in management after knowing IMR values and prognostic implications of IMR in a long term follow up will also be assessed.

NCT Number	NCT06656065
Lead Sponsor	Hospital Miguel Servet Collaborators: Central University Hospital of Asturias, Hospital Universitario La Fe, University Hospital Virgen de la Arrixaca, Murcia, University Hospital 12 Octubre, Madrid, Hospital Universitario Reina Sofia de Cordoba, Hospital Universitari de Bellvitge, Hospitales Universitarios Virgen del Rocío
Conditions	Heart Transplant Rejection, Microvascular Resistance
Enrollment	100 participants
Start Date	2023-05-23
Primary Completion	2028-05-23 (estimated)
Study Completion	2028-10-14 (estimated)
Updated on ClinicalTrials.gov	2025-11-21