Artificial heart helps the beat go on

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Artificial heart helps the beat go on

The FDA's approval of an artificial heart paves the way for wider use. But who needs it?

Heart transplants extend the lives of almost 2,500 Americans each year. Thousands more with failing hearts are literally dying for a transplant.

In the fall of 2006, the FDA gave limited approval to a totally implantable artificial heart, the AbioCor, made by Massachusetts-based Abiomed, Inc. It could help bridge the gap between people who need new hearts and the number available for transplant. The AbioCor represents a huge technological advance over the first total artificial heart. What it can do for its recipients remains to be seen.

Smaller, quieter, and portable

Seattle dentist Barney Clark made history when he received an artificial heart in 1982. That device, the Jarvik-7, was powered by jets of air from a compressor the size of a washing machine that jolted Clark with each beat. Tubes running through his chest that linked the heart and compressor kept him bound to his bed. The heart kept Clark alive for 112 agonizing days, during which he suffered convulsions, breathing problems, kidney failure, and other complications.

Thanks to advances in motors, computer chips, batteries, and design, the AbioCor is smaller, quieter, and more portable than the Jarvik-7. The grapefruit-sized pump (see photo) is completely self-contained. It gets its power from a battery implanted in the abdomen. This internal battery is charged with the help of a device that transfers power through the skin from a battery pack or a plug-in charger.

Photo courtesy of Abiomed

This design offers freedom of movement. The internal battery can power the heart for 20–30 minutes, so a person can easily shower, bathe, or even swim without worrying about power cords or battery packs. The external power pack can run the heart for up to four hours, time enough to go shopping, take a walk, or visit friends. No tubes or wires pass through the skin, which minimizes the chances of an infection.

Since testing began in July 2001, the plastic and titanium AbioCor has been implanted in 14 men with failing hearts, none of whom were expected to live longer than a month.

Two men died from the operation. The others survived an average of five months, with one man living for 10 months and another for 17 months. The heart itself usually worked fine until the end. Strokes, lung trouble, and bleeding problems, especially blood clots, were the main source of complications and death.

Ten of the survivors spent virtually all of their time with the artificial heart in the hospital, going home for a day here or there. One man moved to a hotel room near the hospital that was set up like a hospital room. One eventually went home for a few months.

Who is eligible?

The FDA approved the AbioCor for people with irreversible advanced heart failure that affects both pumping chambers of the heart who are not eligible for a heart transplant and who are unlikely to live more than a month without a new heart.

The pool of candidates is even more limited than that, says Dr. Gregory Couper, who directs the Heart Transplant and Circulatory Assist Program at Harvard-affiliated Brigham and Women's Hospital. The AbioCor is too big for many men, most women, and all children. In general, a person needs to weigh at least 180 pounds or be at least 5 feet 10 inches tall.

From a recipient's perspective, quality of life is an essential concern. As things stand now, that is a gamble. Tom Christerson, the second person to receive an AbioCor, left the hospital after six months for a kind of medical halfway house, and eventually went back to his home in Central City, Kentucky. He was able to celebrate his 55th wedding anniversary, see the birth of his first great-grandchild, and have his morning coffee with friends at the local diner. The fifth recipient didn't fare nearly so well. The New York Times detailed the struggles of James Quinn, who lived for 60 days with an AbioCor. Lung problems and a small stroke coupled with worries about money and health care prompted Quinn to tell a Times reporter that if he could have made the choice over again, he wouldn't have volunteered for the artificial heart program.

Looking ahead

Ongoing work will almost certainly improve the AbioCor. Abiomed retooled the device partway through the 14-person trial to eliminate a strut that seemed to harbor blood clots, and the company is working on a second-generation AbioCor that is 30% smaller and substantially sturdier.

Back in 1964, the U.S. Artificial Heart Program aimed to build an implantable heart in 10 years. More than 40 years later, that goal may be in sight. The next round of implants with the AbioCor, along with continued advances in this technology, will tell us more about how much, and what kind, of time the artificial heart can offer.

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Last updated:	December 01, 2006