A simple box can reboot a stopped heart after it has been removed from a donor’s body, keeping it alive for much longer than if it were shipped in a chiller case. The “heart-in-a-box” machine feeds the heart the nutrients and blood it needs, while keeping it warm and safe in a sterile box.
Ideally, a transplant-destined heart should still be beating when it’s taken from the donor, which–rather obviously–limits the number of available hearts. “Heart tissue rapidly deteriorates when the heart stops beating and blood is no longer being circulated around the heart,” says Transmedics, the maker of the heart-in-a-box device. Up until now, the trick has been to chill the hearts of brain-dead donors while still in the body, then remove and ship them. “Cold temperatures cut the tissue’s metabolic rate by about 90 percent, creating time to reach the recipient,” says MIT Technology Review.
The new machine keeps the organ alive and at operating temperature. But it can also restart a stopped heart after it has been removed. This increases the number of possible donors, because hearts can now be harvested from dead people, just like kidneys and other organs.
While heart supplies are short in general, in the UK there is a vicious irony at work. Because handguns are illegal, there are few shootings, which means that the country doesn’t have a ready supply of brain-dead patients to provide fresh hearts. The use of “warm perfusion machines,” like Transmedics’ heart-in-a-box, could add 50 hearts to the current annual supply of 180 donor hearts. Currently around 2,400 transplants are performed in the U.S. each year.
The new technology also avoids some of the ethical problems with removing hearts from brain-dead or dying donors. How long does one wait before cracking open the chest and cutting out the heart of a just-dead patient, for example?
With warm perfusion machines, the ethics of heart donation will be essentially the same as those for any other organ.