FreeDNA-CAR is a prospective, observational multicenter study, that will include a total of 200 adult heart transplant (HT) patients from 14 centers in Spain. Our main objective is to test donor-derived Cell-Free DNA (dd-cfDNA) against endomyocardial biopsy (EMB) for the diagnosis of acute cellular rejection.

All patients will be enrolled immediately after HT, and will undergo undergo routine surveillance EMB at 15 days, 1 month, 2, 3, 4, 6 and 12 months after HT. Simultaneously with each EMB, dd-cfDNA will be measured in plasma.

Inclusion Criteria:

• Patients > 18 years old who undergo heart transplant during the recruiting period

Exclusion Criteria:

• Patients with moderate or severe Primary Graft Dysfunction
• Patients on invasive mechanical ventilation 15 days after heart transplant
• Patients on renal replacement therapy, continuous or periodic, 15 days after heart transplant
• Heart Transplant due to a cardiomyopathy that could potentially recur on the graft (cardiac amyloidosis, Chagas disease or sarcoidosis, amongst others)
• Multiorgan transplant

Heart transplant recipients aged 18 and over