To evaluate the effectiveness of the OCS Heart System to resuscitate, preserve and assess hearts donated after circulatory death for transplantation to increase the pool of donor hearts available for transplantation.

A prospective, randomized and concurrent controlled, non-inferiority pivotal trial in which subjects who receive a DCD donor heart transplant will be compared to subjects who receive a standard criteria donor heart transplant (Standard of Care 1 [SOC1] and Standard of Care 2 [SOC2] - from both randomized and concurrent control groups), adjusting for differences in risk factors.

Donor Inclusion

• Maastricht Category III DCD donor, defined as expected death after the withdrawal of life- supportive therapy (WLST)
• Donor age 18-49 years old inclusive
• Warm ischemic time (WIT) ≤ 30 mins, with warm ischemic time defined as: Time from when mean systolic blood pressure (SBP) is < 50 mmHg or peripheral saturation < 70% to aortic cross-clamp and administration of cold cardioplegia in the donor.

Donor Exclusion

• Previous cardiac surgery
• Known coronary artery disease
• Cardiogenic shock or myocardial infarction, or
• Sustained terminal ejection fraction (EF) of ≤ 50%, or
• Significant valve disease except for competent bicuspid aortic valve

Recipient Inclusion

• Primary heart transplant candidates
• Age ≥ 18 years old
• Signed: (1) written informed consent document; (2) authorization to use and disclose protected health information; and (3) consent to TransMedics' use of recipients' United Network for Organ Sharing (UNOS)/Organ Procurement and Transplantation Network (OPTN) data and recipients' Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) data.

Recipient Exclusion

• Prior solid organ or bone marrow transplant
• Chronic use of hemodialysis or diagnosis of chronic renal insufficiency
• Multi-organ transplant
• Investigator unwilling to randomize to either arm.