c.*Selection of recipient*

Recipients are selected according to recipient selection criteria for each organ stipulated by the Ministry of Health, Labor, and Welfare. Heart transplant recipient selection criteria were established when the Organ Transplantation Act was enacted in October 1997, and after several revisions, were finally revised in November 2012.

First, as matching conditions, ABO blood group identity (identical) and compatibility (compatible) are targeted, and matching is given priority over matching. In addition, a weight difference (donor/recipient) of −20 to +30% is desirable, but the actual selection does not exclude cases outside that range and is a case-by-case decision. In adults, transplantation from a 20% smaller female to a larger male has been identified as a risk factor for premature graft failure. On the other hand, in the case of children, even if there is a large weight difference, the decision is made on a case-bycase basis. If the donor's heart is large, the number of days until chest closure and the length of stay in the ICU tends to increase, but it is said that there is no effect on the survival rate.

In addition, a lymphocyte direct cross-match test (direct cross-match) is carried out at the transplant testing center using the donor's T-cell lymphocytes and the recipient's T-cell lymphocytes, which are blood-collected and cryopreserved in advance. The recipients whose test is positive are excluded from the recipient list. In addition, if there is a blood transfusion within the last 4 weeks, it is necessary to conduct a new direct lymphocyte crossover test using fresh blood. If the panel test (PRA) test is negative, the lymphocyte direct crossover test can be omitted, but currently, all cases are not omitted and the lymphocyte direct crossover test is performed.

Since it is desirable that the permissible ischemic time is within 4 hours, transportation means will be arranged with a goal of 2 to 3 hours for transportation from the donor facility to the transplant facility.

The recipient's medical urgency is divided into three, Status 1 is the state of wearing a ventricular assist device, an intra-aortic balloon pumping, and extracorporeal membrane oxygenation, the state of being under mechanical ventilation management, or the state of requirement of intensive care receiving continuous administration of inotropic drugs in the intensive care unit. For registrants under the age of 18, even if they are receiving continuous administration of inotropic drugs but are not in the critical care unit, they will be registered as Status 1 (however, if they reach the age of 18 in this condition, they will be registered as Status 2). Status 3 is a state in which the registrant of Status 1 or 2 is temporarily removed from the list due to an exclusion condition such as an infectious disease. Status 3 returns to the original Status when the exclusion condition is resolved. Regarding age, heart donations from donors under the age of 18 will be given priority over applicants under the age of 18 at the time of enrollment. In addition, heart donations from donors aged 18 and over are given priority to applicants under the age of 60 at the time of registration. If medical urgency, age, and blood type are the same, the order of the list of Status 1 registrants is defined by the Status 1 waiting period and that of Status 2 registrants is defined by the total number of days from the date of registration.
