In a landmark operation that could lead to the saving of thousands of lives, doctors in Kentucky have implanted the world's first self-contained mechanical heart.
It took seven hours for surgeons at the University of Louisville to implant the titanium-and-plastic pump, made by Abiomed Inc. of Danvers, Mass.
Cardiologists and others who daily see the results of congestive heart failure - which kills about 46,000 Americans each year - called implantation of the AbioCor artificial heart a major scientific advance.
"It's a monumental step," said Dr. G. Kimble Jett, a cardiac surgeon at St. Joseph's Medical Center in Towson.
Added Dr. John Conte, head of the Johns Hopkins University Medical Center heart-lung transplant program: "This is something we've all been looking for."
Officials at Abiomed and at Jewish Hospital in Louisville, where the operation was performed, did not reveal the identity of the patient or details of the procedure.
The patient was "awake and responsive" was all a hospital spokeswoman would say yesterday. Details of the operation were expected to be given at a news conference this morning.
Abiomed received permission from the U.S. Food and Drug Administration in February to test the device on up to 15 people at these hospitals around the country: Jewish Hospital in Louisville; Brigham & Women's and Massachusetts General in Boston; Hahnemann University Hospital in Philadelphia; the Texas Heart Institute in Houston; and the UCLA Medical Center in Los Angeles.
The company sought only volunteers who suffered from chronic heart disease, were thought to have fewer than 30 days to live and were deemed ineligible to receive a human heart transplant. Most are so sick they can't walk or get dressed by themselves.
Even those who receive the experimental heart aren't guaranteed survival. Company officials said they would be happy if the device extends the life of volunteers 60 days.
Doctors and engineers will watch to see how the AbioCor heart performs. Blood must flow smoothly through the device without life-threatening clots forming, a problem with earlier artificial hearts.
`We may have failures'
Experts cautioned that many years of tinkering and human trials likely remain before such mechanical replacement hearts are routinely sewn into dying patients.
"We need to understand that, with this new technology, we may have failures," David M. Lederman, Abiomed's president and chief executive officer, cautioned.
But the experimental heart - the first to receive government approval in more than a decade - is considered a technological leap from mechanical hearts developed in the 1980s, which were attached by wires and tubes to machinery outside the body.
Since the debut of the first artificial heart in 1982, bioengineers have created other devices, such as ventricular assist pumps, to keep diseased hearts alive until donated replacements become available. Those "bridge" devices remain imperfect solutions at best. They typically require patients to be tethered to a tangle of hoses and wires, leaving them susceptible to deadly infection.
Many people die waiting for heart donors. Of the more than 4,200 people on the list to receive a donor heart, typically only about half get one.
`Not enough hearts'
"We clearly need something in addition to transplantations. There aren't enough hearts to go around," said Jett of St. Joseph's.
The AbioCor is the first wireless artificial heart and the first designed to be a permanent replacement.
About the size of a grapefruit, the 2-pound pump contains a small electric motor attached to an implanted battery.
Power is sent from a battery pack worn outside the body through the skin to an implanted coil, control package and backup battery.
The internal battery, about the size of a typical pager, can work on its own for about 30 minutes between charges - long enough for a patient to take a shower, for example. To recharge the battery, a patient plugs it into a wall socket.
Reacts to activity level
Like a real heart, the AbioCor is designed to react to a patient's activity level, pumping less blood when he is, say, watching television and more when he is exercising.
The 20-year quest to create a heart has proven a "supreme engineering challenge," said Dr. David A. Meyerson, a cardiologist at Johns Hopkins. And for good reason: Engineers are trying to duplicate one of nature's most durable machines.
Must be reliable
A human heart beats 100,000 times a day - 35 million beats a year - pushing more than five quarts of blood through the body every minute. An artificial heart has one further design requirement that most other devices - from the space station on down - don't: It must not break down.
"You don't have any leeway anywhere," said Alan Snyder, a bioengineer at Penn State's Milton S. Hershey Medical Center who has spent the past two decades designing artificial hearts.
The first artificial heart, the Jarvik-7, was implanted into a Seattle-area dentist in 1982. Attached to a 350-pound power unit, Barney Clark lived 112 days.
The longest anyone has survived on a completely artificial heart is 620 days.
But although this early generation of artificial hearts didn't always live up to the media hoopla, the devices taught scientists valuable lessons - and saved lives.
The Jarvik-7 kept Thomas Gaidosh of Sutersville, Pa., alive long enough to receive a human heart transplant. He lived 11 more years, long enough to serve as best man at the wedding of inventor Dr. Robert Jarvik.
Wire services contributed to this article.
