Andrea Ybarra, a 40-year old woman from Los Angeles is one of a few patients to receive a “beating heart” in a transplant operation that uses a new method where the donated heart is kept supplied with warm oxygenated blood while it awaits transplantation into the recipient.
Doctors hope the new method will extend the life of transplant organs, which can deteriorate and become useless once they are no longer supplied with blood.
Ybarra has lupus, a condition where the immune system attacks the organs, including the heart, causing inflammation of the sac around the heart, the muscle, the lining and the arteries supplying blood to the heart.
She is one of a few patients in the US to take part in a trial that is comparing the safety and efficacy of the beating heart method against the traditional system that keeps the donor heart inert in a cooler box while it awaits transplant into the recipient, reports the Associated Press.
The US-based trial, led by the University of California, Los Angeles (UCLA), where Ybarra’s transplant took place, is sponsored by TransMedics Inc, who make the Organ Care System (OCS) being tested in the trial. They are a private medical device company with headquarters in Andover, Massachusetts.
The OCS beating heart box keeps the heart in a “near physiologic beating state” while it is outside the body. It perfuses the heart with warm oxygenated blood supplemented with nutrients and electrolytes.
The idea is that this method protects the heart from damage and thereby extends the “shelf life” of donated organs and maximises the chances of successful transplants, say TransMedics.
For instance, it gives doctors time to examine the donor heart for any damage and the opportunity to better match it with a recipient.
So far, about 100 patients have received a new heart using this method, most of them in Europe and early signs are encouraging, according to TransMedics. Two European experiments with 54 patients have shown a 97 per cent survival rate a month after the surgery and low incidence of rejection and other complications.
However, those trials did not test the device against the current method, which has been in place since the 1960s when the first heart transplants were performed.
In the current method, an inert heart, that has been injected with a chemical to preserve it, is transported in an ice chest not unlike a picnic cooler packed with ice.
Then it is a race against time as the organ only has a shelf life of around 4 to 6 hours. This limits the geographic range of recipient locations, and it also gives little time to assemble the transplant team: some transplant operations start in the early hours of the morning.
Dr. Bruce Rosengard of Massachusetts General Hospital in Boston, performed the first beating heart transplant at Papworth Hospital in Cambridge, United Kingdom, in 2006. He told the Associated Press that the beating heart system takes the rush factor away, and means he could “go all the way to the West Coast to get a heart”.
When he carried out the operation in the UK, he told the BBC that normally, under the current system, the heart is kept in “suspended animation” on ice, but they still deteriorate.
In the OCS system, once the heart is hooked up, which takes about 20 minutes, “any deterioration is fully reversed”, said Rosengard.
TransMedics suggest that the new US-based trial, called PROCEED II, will involve about 128 patients who will have a 50% chance of receiving a heart transported using the new system, and a 50% chance of receiving a heart under the cold storage system.
The success of the trial will be determined by primary and secondary endpoints. The primary endpoint will be the 30-day survival of patient and transplanted heart, and the secondary endpoints include the incidence of cardiac-related serious adverse events, time in ICU, and incidence of acute rejection episodes, said TransMedics on their website.
However, even if the trial succeeds clinically, there will be other barriers to overcome. One is how will patients feel about receiving a beating heart, and the other, arguably an even greater barrier, is the cost.
The total cost of a heart transplant in the US, including hospitalization and drugs to stop the immune system rejecting the new organ, is just under 800,000 dollars. The currently used chest cooler box, which costs less than 100 dollars, is a negligible part of that, whereas in Europe, the beating heart box costs around 200,000 dollars. The insides of the box have to be replaced every time, so that is an additional cost for each operation.
Arthur Caplan, chair of the Department of Medical Ethics at the University of Pennsylvania, said to the press just after the University of Pittsburgh Medical Center’s (UPMC) Presbyterian Hospital carried out the first US beating heart transplant in Oakland in 2007, that he thought the benefits outweighed the costs, and as to the “macabre aspect, “beating hearts in boxes, Edgar Allen Poe and the heart beating below the floorboards”, people will adapt to the idea.
Ybarra said when she woke up from her operation she wasn’t scared: “”I felt peaceful”, she said, and “It felt like the heart was a part of me all the time”.
Ybarra’s operation was in August this year. Since then her health has improved, reports the Associated Press. She can walk around the block without getting tired: before she could hardly take a few steps.
She had a check up in October, which involved taking a biopsy of her new heart, checking the scabs on her chest, and undergoing an echocardiogram, which looked normal.
Around 3,000 Americans are on the heart transplant waiting list. Last year 359 patients died waiting for a new heart, that is nearly one every day.
Sources: Associated Press, BBC, TransMedics, TribLive.
Written by: Catharine Paddock, PhD