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State-of-the-Art Artificial Heart

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July 5, 2001 (Washington) -- It's been almost 20 years since doctors at the University of Utah announced successfully implanting a total artificial heart in Barney Clark. But euphoria rapidly lead to tough questions as Clark's health deteriorated during his grueling 112 days on the Jarvik 7.

Did the gain outweigh the pain? What quality of life did the machine provide for people like Clark, a lifelong smoker whose heart was barely pumping blood? Now there's a new-generation artificial heart, and backers say it's light-years away from the Jarvik 7.

The older device relied on a cumbersome external air compressor for power, and on tubes that run through holes in the skin and drive a plastic and aluminum pump. By contrast, the AbioCor manufactured by ABIOMED uses a radically different approach: The business end of the grapefruit-sized device is totally implanted inside the body.

It's the first machine of this type to replace a failing heart, and it's been decades in the making. "This is probably the most sophisticated, bio-engineered implant that's ever been made," says John Watson, MD, who heads the clinical and molecular medicine program at the National Heart, Lung, and Blood Institute.

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Watson says he's been both coach and cheerleader for the artificial heart program for some 25 years. The effort to develop a machine to replace the heart dates back at least to 1963, he says, when famous cardiovascular surgeon Michael DeBakey, MD, told a U.S. Senate committee that such a machine was needed.

"It's [been] kind of a long dream in a way," says DeBakey, who tells WebMD the new device sounds promising. At the time of the original proposal, however, he says, the director of the National Institutes of Health felt the artificial heart was a "waste of money," because there wasn't enough scientific information to justify proceeding.

However, over the next three decades that situation changed dramatically as the contribution of federal dollars increased. Watson says that $100 million was pumped into artificial heart research while a similar amount of money was directed to heart-assisting devices.

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These left-ventricular assist devices, or LVADs, can keep a patient going until a transplant becomes available. Less complex than an artificial heart, four LVADs have already been approved by the U.S. Food and Drug Administration, and one has sustained a person for four years.

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Ironically, some of the artificial heart's early backers have switched much of their support to LVADs. One reason, they say, is that the LVAD might be a better tool in the long run for the 75,000 Americans who suffer from heart failure annually.

In fact, the inventor of the Jarvik 7 tells WebMD that total artificial hearts are too large for most of the small percentage of patients who could benefit. Robert Jarvik, MD, says he's changed his thinking a lot since the days of Barney Clark and now has an experimental bridge-to-transplant device called the Jarvik 2000.

"I believed at the time that was a very good approach. However, I think experience teaches something, and one of the big issues in terms of removing the heart, and putting in a device of this nature, is reliability," he tells WebMD.

As for the AbioCor, it operates on a motorized, fluid-driven pump. As the fluid is pushed from one chamber of the heart to the other by a valve, it generates enough energy to pump blood through the body.

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"ABIOMED is a 20-year-old technology that's been brought out in very glowing terms," says Jarvik, who received a $5 million grant to develop his new device.

But Watson insists it's too soon to argue about which is the superior technology. "I'm not sure why people are so eager to enter into the debate," he says, when there's no follow-up data from even one patient yet.

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