Table 1.

Pig to non-human primate xenograft models

Xenograft model	Description	Features	Accepted for clinical trials	Scientific rationale
Abdominal heterotopic	System with two anastomoses: the infrarenal aorta supports the coronary arteries of the donor's heart while the recipient's inferior vena cava drains blood from the donor's pulmonary artery	The pig's heart is contractile but cannot support the recipient's circulation	No	To study the mechanisms of rejection and the possible patterns of immunosuppression.
Orthotopic	The recipient's heart is replaced with that of the pig.	It can support circulation but with difficulty.	Yes	To study the mechanisms of rejection and the possible patterns of immunosuppression. Evaluate the hemodynamic efficacy of the transplant.
Intrathoracic heterotopic	The pig's heart is placed on the right side of the recipient's chest and supports circulation.	It combines the safety of heterotopic transplantation with the fact of having a heart capable of supporting circulation.	Yes	To study the mechanisms of rejection and the possible patterns of immunosuppression. Evaluate the hemodynamic efficacy of the transplant.