Biotechnologies Track

15:30 - 16:45

"Machine Perfusion for Heart Transplantation"

Michael Cobert

Organ Transport Systems

Cardiac transplantation has emerged as a life-saving procedure for patients with end-stage heart failure over the past 40 years. Over most of that time the general technique of cardiac preservation has changed little. Hearts today are preserved by flushing them with a cold potassium-based crystalloid solution, and then storing them in a container filled with preservation solution that is placed within an ice chest to maintain organ hypothermia during transport. Despite this rather crude technique, results of cardiac transplantation are good with patients receiving donor organs having a predicted survival half-life of 10 years. However, the current technique has limitations, and graft storage and transport beyond 5 hours lead to significantly reduced 1-year survival.

Moreover, early graft failure remains a significant problem and is responsible for 40% of deaths that occur during the first month following cardiac transplantation. Patients who survive the first year have an excellent outlook with a conditional half-life of nearly 13 years. Therefore, any technique that can improve early graft performance may substantially improve the results of cardiac transplantation.

The current cardiac preservation strategy for cardiac transplantation involves arresting hearts with a crystalloid preservation solution and storing them in this solution in an ice chest. This technique has allowed good results in heart transplantation, but has limited the transport interval, and has not encouraged major efforts to expand the donor pool. Machine perfusion of explanted organs, a technique used clinically in kidney transplantation, is now under active investigation in the cardiac arena. This review examines the current status of this technology.

Recent experimental studies in animals have tested machine perfusion for cardiac preservation. This technique appears to reduce the allograft ischemic burden, may permit longer preservation times, and improves early ventricular function upon reperfusion of the donor heart. The metabolic profile of the stored heart appears better preserved with machine perfusion; however, investigators have noted a risk of edema development in perfused cardiac grafts.

Early experimental results are encouraging and suggest that machine perfusion may offer superior cardiac performance after transplantation. In the future, this technology may lead to an expansion of the donor pool through greater use of expanded-criteria donors, resuscitation of ischemically injured hearts, or procurement of hearts that are donated after cardiac death.