Whither the Artificial Heart?
Doctors are optimistic despite pioneer's death
MONDAY, Dec. 10, 2001 (HealthDayNews) -- Robert Tools had diabetes and kidney disease and was growing progressively weaker when he arrived at Jewish Hospital in Louisville, Ky., in July. Doctors told him he had congestive heart failure. He had about a month to live.
They also presented him with an option, albeit a risky one. Was he interested in becoming the first recipient of the world's first self-contained, artificial heart?
Tools, 59, a retired librarian from nearby Franklin, Ky., decided to go for it. "I realize that death is inevitable," he said when he met the press. "I had a choice to stay home and die or come here and take a chance," he said.
During the 151 days he lived with the heart, he went fishing and ate cheese steaks with Louisville's mayor. On Nov. 30, he succumbed to internal bleeding and organ failure.
In light of Tools' death, questions remain about the future of the artificial heart. Will it save the lives of the thousands of people who would otherwise die of heart failure, or is it a bit of medical science fiction that will forever be a technological impossibility?
Heart surgeons are optimistic.
"Most heart surgeons are convinced artificial hearts will be very commonly used in the future," says Dr. Irving Kron, chief of heart surgery at the University of Virginia. "It's really quite exciting."
When a patient is diagnosed with heart failure, doctors currently have several treatment options, including drugs and surgery.
If those methods fail, surgeons turn to a heart transplant, but there aren't nearly enough donated hearts to go around.
"The number one reason for considering mechanical hearts is that we have a growing number of people dying prematurely from heart failure," says Dr. Timothy Gardner, chief of cardiothoracic surgery at the University of Pennsylvania Medical Center. "There are many more people who are in this condition than we have hearts available for transplantation."
Transplanted hearts also carry the risk of rejection. Patients have to take heavy doses of immune-suppressing drugs, which can have side effects, for the rest of their lives,
Human tests on artificial hearts began 19 years ago, when Dr. Barney Clark, a Seattle dentist, became the first person to receive a mechanical pump. The device, called the Jarvik-7, kept Clark alive about four months. William Schroeder of Jasper, Ind., lived the longest with an artificial heart. He survived 620 days with a Jarvik-7 before his death in 1986.
The first generation of artificial hearts had wires and tubes protruding from the chest and tethered to external compressors. Outside connections are prone to infection.
Tools received a more technically advanced device, called the AbioCor heart. It was internal and self-contained. Tools did, however, need to carry a battery pack, according to AbioMed, Inc., of Danvers, Mass., the company that makes the device.
The battery pack works for several hours before it needs recharging, the company says. The AbioCor heart also has an internal battery that lasts about a half-hour, letting Tools do things like take a shower without the external battery pack.
While the AbioCor heart is a major advance over the Jarvik, it still needs far more fine-tuning before it could benefit large numbers of patients, Kron says.
"The problem is the devices being used are still primitive," he says. "We're not quite ready for prime time."
Four other patients are now living with AbioCor hearts. A fifth died during surgery to implant the heart.
Other companies also are developing artificial hearts, including devices that replace only one of the two heart ventricles. The left ventricle pumps blood from the heart to the body, while the right ventricle pumps blood returning from the body into the lungs.
In the majority of heart failure cases, only one ventricle ceases working, Gardner says. Because single-ventricle artificial hearts are by definition less complex, they may have a better chance of working on more patients sooner, he says.
While Tools' death was not caused by a malfunction of the mechanical heart, his death was related to having an artificial device in his body, Gardner says.
Previous research has shown that blood that comes into contact with artificial material has a tendency to form clots. Tools took anticoagulants, or blood thinners, to reduce this possibility.
But one side effect of blood thinners can be internal bleeding, which is what killed Tools. Still, Gardner says, "It's totally appropriate to be pursuing this technology."
"It's like any technology: The first versions are inefficient and cumbersome. As more experience and development goes on, they tend to become better and better. The AbioCor prototype is a pretty exciting development," Gardner says.
What To Do
To read more about the AbioCor heart, check the Implantable Artificial Heart Project.
For more on heart disease and heart failure, try the Centers for Disease Control and Prevention.