A blood-pumping device commonly referred to as the Berlin Heart, which bridges children to transplant while they’re awaiting a heart, is facing imminent approval by the Food and Drug Administration (FDA). It’s already approved in Canada and has been used Europe since 1990.
Currently, pediatric heart surgeons have to get special approval from the FDA on a case-by-case basis to use the device. The process, part of the FDA’s compassionate use program, requires a bureaucratic undertaking involving letters of support from several other physicians. The process isn’t onerous, but it takes up valuable time that many children don’t have.
FDA approval “will change things dramatically,” says Dr. Robert Stewart, chair of the department of pediatric thoracic and cardiovascular surgery at Cleveland Clinic Children’s Hospital, who most recently implanted a Berlin Heart on Wednesday. “It’s pretty easy to go through the [compassionate use request] process, but this is life-support stuff. You kind of need the heart on your shelf so you can say ‘This kid needs life support, let’s do it first thing in the morning.'”
Children awaiting a heart have the highest mortality rate of any group requiring a solid organ donation, according to 2009 study in the medical journal Circulation. The study found that in 1999 to 2006, nearly 4,000 children were listed for heart transplant. Among those, 17% died while waiting for a donor organ; 63% received a transplant, 8% recovered and 12% remained on the registry.
The typical transplant recipient waits about four months, though the wait could take years. Most children needing a new heart suffer from congenital conditions, such as cardiomyopathy, a chronic disease of the heart muscle; in many cases, such heart conditions may have been corrected with surgery in infancy, but fail later in childhood. Thus, most donor-heart recipients are either younger than 1 or between 11 and 17 years old.
In the past year, 100 American children needing a transplant have received the Berlin Heart, either through the compassionate use process or as part of a clinical trial. Most survived until transplant. In one clinical trial at Duke Children’s Hospital, the rate of survival was 90%. Complication rates were also high, however: in one trial presented to the FDA over the summer, 92% of one cohort of patients had a major or minor complication associated with implantation of the device, such as infection or bleeding, and nearly 30% had a major neurological event, most often a stroke caused by a blood clot associated with the device. In another study, 79% of patients suffered complications and, again, nearly 30% had a neurological event.
Patients using the Berlin Heart are required to take massive doses of blood thinners — both anticoagulants and platelet-inhibitors — to reduce clotting, but these drugs also contribute to stroke risk by increasing the risk of bleeding in the brain. Still, says Dr. Stewart, the device’s benefits outweigh its considerable harms. “Yes, that’s a high rate, but it’s also in patients who essentially would be otherwise dead,” he says.
The the only option aside from the Berlin Heart for children whose hearts have failed but are still waiting for a donor organ is a last-resort intensive-care treatment called extracorporeal membrane oxygenation (ECMO). ECMO, which uses an external artificial lung to oxygenate blood before returning it to the body, requires children to be confined to their beds, heavily sedated and unable to consume solid food.
Because ECMO requires blood to travel a great distance in and out of the body, it puts patients at risk of infection. Indeed, children who used ECMO were three times more likely to die than children who didn’t, the 2009 Circulation study found. In part, that finding may have to do with the fact that ECMO is a last resort: children who need it tend to be sicker than other heart transplant candidates.
The Berlin Heart also consists of an external pump and implanted tubes, but circulates blood closer to the body. It is small enough to allow children to move around and eat regular meals. But because it is an external device, it still requires hospitalization of the patient. It has been used for more than a year in some instances, however, compared with two weeks for ECMO.
An FDA advisory panel that convened in July recommended the device’s approval, and Stewart says word from the agency is expected “any minute.” It will be approved for use in infants and children aged 16 or younger who are suffering from severe heart failure and are close to death.
Even after approval, Stewart expects use of the device, technically known as the Excor pediatric ventricular assist device, manufactured by Berlin Heart, Inc., to be relatively uncommon, estimating that perhaps 150 to 200 devices will be implanted in the coming year.