Transplantation of the heart and both lungs. II. Experimental cardiopulmonary transplantation.

It is estimated that an unknown, yet possibly large, number of patients would benefit from transplantation of the heart and both lungs if technically, physiologically, and immunologically feasible. In this paper we attempt to explore the main non-immunological areas in which we feel that cardiopulmonary transplantation requires further evaluation. A technique is described by which the heart and lungs, as one unit, can be removed from a donor animal, and viability of these organs can be maintained for several hours by autoperfusion (circulation being through the coronary and pulmonary vessels) with positive pressure ventilation via the trachea. This simple heart-lung preparation preserves the organs concerned for sufficient time to allow preparation of the recipient, transport of the donor organs, and tissue typing to be carried out. Our technique of implanting these donor organs into the recipient is also described. We have carried out this operation on approximately 100 dogs and have been impressed by the good cardiac function obtained, but spontaneous respiratory function has been either absent or inadequate to sustain life for more than a few hours. It would appear that dogs cannot tolerate bilateral pulmonary denervation, and our findings are discussed in the light of other work on this subject. Work on primates suggests that man would be able to undergo this procedure successfully. The organizational and ethical problems involved in cardiac and cardiopulmonary transplantation are briefly discussed.