Aug. 25, 2004 -- An artificial heart keeps heart failure patients alive long enough to receive a heart transplant -- welcome news for the 5 million Americans living with this condition.
Researchers report that 79% of heart failure patients implanted with the CardioWest Total Artificial Heart survived long enough to get a heart transplant. By comparison, less than half of similarly ill patients who didn't get the device survived to get a heart transplant. Artificial hearts are often called a "bridge" to transplant because it buys the patient some time while waiting for a donor heart.
The device received the cautious backing of an FDA advisory panel in March but has not yet received official approval for its use in the U.S. Although the FDA hasn't yet ruled on whether to approve the device, it typically follows the recommendations of its advisory panels. The study is published in this week's edition of The New England Journal of Medicine and was presented earlier this year before the FDA panel.
The artificial heart used in the study is modeled after the Jarvik-7 artificial heart, which gained notoriety in the 1980s when it was implanted into Salt Lake City resident Barney Clark. But Jarvik-7 failed as a permanent artificial heart for critically ill patients. The CardioWest Total Artificial Heart is being evaluated as a "bridge" to transplantation -- as a way to buy time for patients until they can get an actual transplant.
1 in 4 Dies Waiting for Donor Heart
An estimated 100,000 heart failure patients need a heart transplant to live, since their condition is too severe to be helped with drugs or other treatments. But fewer than 2,500 transplants are performed each year, largely because of a lack of available donor organs. It's estimated that one in four people on the national waiting list for heart transplants dies while waiting for an available heart for transplantation.
"So there are 98,000 patients who fall through the cracks," says study researcher Marvin J. Slepian, MD, director of interventional cardiology at the University of Arizona College of Medicine and president of the company that manufactures the device, also being used in Europe.
"The way to look at this is this is one small step in treating end-stage heart failure, but from a technology point of view, it's a major step," he tells WebMD. "Ultimately, the goal is to develop a technology that not only will bridge a patient to transplant, but for some patients who will never get a transplant to develop a platform that could be utilized for longer-term therapy. But like everything in science, you have to walk before you run."
For the study, the research team at the Sarver Heart Center at the University of Arizona tracked 81 patients over nine years who received an artificial heart. They also observed a comparison group of 35 others who didn't get the artificial heart.
Some of the researchers, like Slepian, are also officers of SynCardia Systems, Inc., of Tucson, the makers of the CardioWest Total Artificial Heart.
One year after receiving the artificial heart, 70% of those getting the device were still alive, compared with only 31% of those in the comparison group. Sixty-six percent of patients in the implanted group were still alive after five years, the researchers report.
Advantage Over Current Treatments
With heart failure, the heart's main pumping chambers -- or ventricles -- become too weak to pump blood. Currently, doctors implant a device in some patients called a "ventricular assist device" to help the heart pump blood. But when both of the heart's pumping chambers fail, these devices may not be effective.
But the artificial heart may be a solution for these patients. To implant the device, surgeons cut off the bottom half of the heart and sew the artificial heart onto the top chambers; it's then powered by a large, washing machine-sized air generator to keep blood pumping until an actual heart can be transplanted. A smaller, more portable unit is being developed to allow patients more mobility following implantation, says Slepian.
Still, his study shows that the artificial heart malfunctioned in 17% of patients, causing death in one patient. The device also resulted in infection in 77% and bleeding in 62%. Fitting the bulky device proved troublesome in 5%, and about one-third developed respiratory problems.
Most of these complications were minor, says Slepian, but had to be noted for the FDA panel review. "If they had a slight temperature bump, we noted it as an infection, but nothing was life-threatening," he tells WebMD.
One Life Worth the Effort
One expert not involved in the research says the artificial heart and this study deserve notice.
"Since the 1980s, more than 6 million people have died of heart failure in the United States alone. A mere fraction of that group -- fewer than 50,000 patients -- received transplants," Dale G. Renlund, MD, director of the Heart Failure Prevention and Treatment Program at the University of Utah, writes in an accompanying editorial.
"Although not all patients with heart failure can currently be saved ... we should embrace this technology because it increases our ability to help some patients."