Heart transplantation offers a second chance at life for people suffering from end-stage heart failure. The complex procedure involves replacing a failing heart with a healthy one from a deceased donor. Success depends on the availability of a viable donor organ and a precise, time-sensitive sequence of events, including donor identification, medical suitability, retrieval, and allocation.
Eligibility Requirements for Heart Donors
Heart donor requirements are strict due to the organ’s sensitivity. The primary criterion is the determination of death, traditionally occurring after brain death, known as Donation after Brain Death (DBD). In DBD, the patient has suffered an irreversible loss of all brain function. The heart continues to beat and perfuse the organs until retrieval, ensuring the heart remains in optimal condition for transplantation.
Medical suitability requires assessing the donor’s health history and cardiac function. While there is a preference for younger individuals, the upper age limit depends on the heart’s overall health. The heart must be free of severe coronary artery disease, chronic illness, or transmissible infectious diseases. Maintaining organ viability requires intensive medical support, including managing blood pressure and administering hormones until retrieval.
Donation after Circulatory Death (DCD) is an alternative where death is declared after the irreversible cessation of the heart and lungs. DCD was historically less common because the lack of blood flow causes warm ischemia, quickly damaging heart tissue. Advancements in preservation techniques, such as ex situ perfusion devices, are expanding the use of DCD hearts. The time between the heart stopping and the start of organ preservation is a constraint, requiring completion within a short window to prevent irreversible damage.
The Logistical Process of Organ Retrieval
Once a potential donor is identified and declared deceased, an Organ Procurement Organization (OPO) coordinates the next steps. The OPO secures consent, either by confirming the individual’s donor registration or by obtaining authorization from the next of kin. A medical evaluation follows, including blood typing, infectious disease testing, and assessment of the heart’s condition.
The surgical retrieval involves multiple transplant teams traveling to the donor hospital. The heart team prepares the heart for removal, often working alongside teams for other organs. The operation includes cross-clamping the aorta and rapidly infusing a cold preservation solution. This solution stops the heart and cools the tissue, minimizing metabolic activity and preventing cell damage during transport.
The heart’s tolerance for being without blood flow, known as cold ischemic time, is short, typically four to six hours. This narrow window dictates the speed and coordination required for transport to the recipient’s surgical center. The heart is packaged in a sterile container surrounded by ice to maintain the low temperature and ensure viability for transplantation.
How Hearts Are Matched and Allocated
The process of matching and allocating a donor heart is managed by a national computerized system. This system ranks potential recipients based on standardized policies designed to ensure fairness and maximize the chance of a successful transplant. The most immediate factor considered is the recipient’s medical urgency. The sickest patients, who have the highest risk of death without a transplant, receive the greatest priority.
Biological compatibility is a requirement, beginning with matching the donor’s and recipient’s blood type (ABO compatibility). Heart size is also a significant factor, as the donor heart must physically fit within the recipient’s chest cavity and be appropriately sized for their body mass. Children often receive priority for organs from pediatric donors due to the need for size-appropriate organs.
Geographical proximity plays a large role in heart allocation because of the organ’s short ischemic time. The system prioritizes candidates at transplant hospitals closest to the donor hospital to minimize transit time. If no suitable recipient is found locally, the search radius expands regionally and then nationally. Only medical and logistical factors determine the rank order on the match list; personal factors have no bearing on priority.