Artificial hearts could fill the transplant gap

Artificial heart pumping devices that can remain in the chest even for years, Israeli researcher says.

By JUDY SIEGEL-ITZKOVICH
A doctor stands with stethoscope in this undated handout photo. (photo credit: REUTERS)
A doctor stands with stethoscope in this undated handout photo.
(photo credit: REUTERS)
The number of available hearts for transplant is declining in both Israel and the US, while the waiting lists of potential recipients are growing due to more cases of heart failure. The situation, described in an article just published in The American Journal of Transplantation, exists here as well, according to Prof. Jay Lavee, a leading heart transplant surgeon at Sheba Medical Center.
As life expectancy grows, increasing numbers of Americans are developing chronic heart failure (in which the heart is unable to pump enough blood through the body), leading to death within five years in about half of patients. But while queues for available hearts are longer, there is a striking decline in the use of hearts for transplantation in many regions.
“We, as a heart transplant community, are using a small fraction of available donor hearts for transplantation, and we have become more conservative over the past 15 to 20 years in terms of donor heart acceptance,” said lead author Dr. Kiran Khush of the Stanford University School of Medicine. “This finding is troubling in the setting of a national donor heart shortage and an ever-growing number of critically ill patients awaiting heart transplantation.”
Khush and her colleagues examined US national trends in donor heart acceptance for transplantation by analyzing data from the Organ Procurement and Transplantation Network for all potential adult cardiac organ donors between 1995 and 2010. There was a significant decrease in donor heart acceptance from 44 percent in 1995 to 29% in 2006, and a subsequent increase to 32% in 2010. Older donor age, female sex, and medical conditions made it less likely that donor hearts were used. Donor age and medical conditions increased over time, with a concomitant decrease in acceptance of hearts from donors with undesirable characteristics.
The researchers also suggested that donor heart acceptance practices are not standardized around the US and that clinical guidelines are needed for donor heart acceptance, as well as more intense efforts to increase the use of donor hearts in areas with relatively low rates of organ use for transplant.
Asked to comment, Lavee said that in Israel, potential donors used to be primarily brain-dead victims of road accidents. But as the number of such accidents has declined (due to road improvements, better-designed vehicles and improved law enforcement), there are fewer hearts to go around.
“Today,” he said, “hearts for transplants are taken from older people, including stroke victims with lower-brain death.” Hearts for transplant can be taken only from people whose lower- brains have died, but whose hearts continue to beat, while healthy kidneys and even livers and lungs can now be taken from people whose hearts have stopped beating. “The majority of hearts for transplant do not come today from accident victims,” said Lavee. There are fewer brain-dead patients, as there are improved neurosurgery techniques used on accident victims and others, he added.
But the shortage of donor hearts could be offset somewhat, said Lavee, by the use of artificial heart pumping devices that can remain in the chest even for years. “Not all people with diseased hearts are dying,” concluded the Sheba heart surgeon, “and more of them will get artificial hearts for the long term rather than live hearts.”