Two economic procedures and without ethical complications allow to keep the hearts intact to be donated even after the donor’s death.
Two new low-cost and easily reproducible strategies allow you to revive or preserve the hearts of the people who have decided to donate the organs after death from the death processes. The procedures, described in a couple of studies published on New England Journal of Medicine (Nejm)could significantly increase the availability of hearts for transplants, starting with pediatric ones.
Two types of donations
For a long time, most of the hearts available for transplants came from patients declared in a state of brain death, with irreversibly damaged brain, maintained alive by vital support systems that continue to offer oxygen to the organs (and to maintain hearts healthy until the moment of the exploitation).
However, there are not enough cases like these to meet the demand for hearts for patients in life threatening. Furthermore, thanks to the laws on road safety, post traumatic brain death has gradually reduced, and today the donors found in this condition have come following events such as ischemias or brain hemorrhages. Usually, they are suffering from conditions such as diabetes and hypertension that could have damaged heart health.
To make up for the lack of hearts for transplants, in recent years the path of the hearts of donors in cardiac death began to examine, whose heart, that is, has ceased to beat for at least five minutes (in Italy this type of donation, called heart, can only take place after a doctor has certified death with a “flat” electro-cardiogram of at least 20 consecutive minutes).
Ethical dilemmas
The time spent in the absence of oxygen damages the delicate fabrics of the heart, and before being able to use the hearts from donors in cardiac death for transplants it is necessary or revive them out of the body, pumping inside them oxygenated blood, or preserving them through a perfusion of blood while still find inside the donor’s body.
The first option is very expensive and unsuitable for the hearts of donors who weigh less than 40 kg, such as children and babies. The second ethical dilemmas that revolve around the very essence of death.
According to some, reactivating the heart while still in the body may require to review the definition of death as an irreversible termination of all the biological functions that support a living organism; Another concern is that the procedure can theoretically restore a small part of the blood circulation in the brain, even if the blood vessels ranging from the heart to the brain are blocked during these operations.
More hearts for children’s risk children
The first system for circumventing these problems was conceived by Joseph Turek, a pediatric cardiac surgeon of Duke University of Durham (North Carolina) and allows you to revive the hearts of children and babies outside the body. It consists in pumping oxygenated blood into hearts through a catheter attached to the aorta. Blood then outlines in a suspended tank and passes to an oxgent.
The procedure, simpler and cheaper than the machines of tens of thousands of euros used for adult hearts, takes place on the operating table and allows you to see the heart that begins to revive before it is used for transplantation.
After heading it on pork puppies, this year she was tried on a heart of a one month -old baby, revived and then transplanted to a three -month -old newborn that needed it desperately. After three months from the operation, the organ continued to operate normally without signs of rejection. The technique could increase by a hundred units available for pediatric transplants in the United States, and it could also be tested on adult hearts.
Stored cold
In the second study, the cardiac surgeons of the VanderBut University Medical Center in Nashville, Tennessee have blocked the aorta of the still heart donors with a caliper and filled the hearts with a cold oxygenated fluid that has maintained the organs in a state of relaxation, protecting them from degradation without restarting them. The liquid based on oxygenated blood and other ingredients has restored the oxygenation of the heart and contrasted those metabolic substances that accumulate during the death processes and that deteriorate the organs.
Even if the procedure violates the dogma that requires evaluating a heart before transplanting it, the solution has made its duty. The team successfully transplanted the hearts in the first three adult recipients who did not show signs of rejection in the first six months from the operation. From the end of the study, the researchers repeated the technique on about twenty individuals with a positive outcome.
Both techniques must be tested on more consistent numbers of people before they can enter clinical practice. But they could represent one more opportunity for patients waiting for a new heart.
