New artificial heart fits inside patient
Compiled from Times wires
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LOUISVILLE, Ky. -- A patient on the brink of death has received the world's first self-contained artificial heart -- a battery-powered device the size of a softball that runs without the need for wires, tubes or hoses sticking out of the chest.
During a seven-hour operation, two surgeons removed most of the patient's dying heart Monday at the Jewish Hospital in Louisville, Ky., and implanted the mechanical heart, a yoyo-shaped plastic and titanium pump weighing less than 2 pounds. The surgeons, Dr. Laman A. Gray and Dr. Robert D. Dowling, attached the device to remnants of the heart's two upper chambers and to the aorta.
The hospital did not identify the patient by name or sex, in keeping with a previous agreement to withhold information for an unspecified "quiet period." A hospital statement said the patient was "resting comfortably," but officials refused to say anything further until a briefing today. The implant marked the first significant advance in nearly 20 years in an often stormy quest marked by great excitement about the artificial heart's potential and bitter disappointment when it became clear that the technology was prolonging suffering instead of saving lives.
Today the debate has changed. Some experts praised the new device because it is totally enclosed in the human body, sharply reducing the risk of infection, a crucial shortcoming of earlier efforts. But other experts suggested that new technologies, including implantable heart assist devices, advanced surgical techniques and medications, had made artificial hearts a needless alternative in all but a handful of cases.
The first recipient of an artificial heart, Barney Clark, a Seattle-area dentist, lived 112 days after receiving a Jarvik-7 in 1982. William Schroeder of Jasper, Ind., lived longest with a complete artificial heart -- 620 days before he died in 1986.
The inventor of the Jarvik-7, Robert Jarvik, dismissed the technology he helped pioneer as "obsolete," and described the new device as "false hope and a sincere, but misdirected effort."
The device was developed by Abiomed Corp. of Danvers, Mass., which announced in April that the company had gotten permission from the Food and Drug Administration to implant its AbioCor heart in at least five individuals at any of five hospitals around the country.
Besides Jewish Hospital, the other participants include Brigham and Women's Hospital, teamed with Massachusetts General Hospital in Boston; Hahnemann University Hospital in Philadelphia; the Texas Heart Institute in Houston; and the UCLA Medical Center in Los Angeles.
Candidates for the implant must be ineligible for transplant and have "end stage" heart disease so grave that death is anticipated within a month, company president David Lederman said. He cautioned that even with the implant, "every single patient is going to die on AbioCor," and that the modest goal of the initial trials was to prolong the patients' lives to 60 days. Only if this can be achieved, he added, would the trials be expanded to include more patients.
The human experiments also are to determine whether the AbioCor's use causes any pain, interferes with mental acuity and can allow a patient to carry out routine daily activities and be productive.
John Watson, director of clinical and molecular medicine for the National Heart Lung and Blood Institute, which funded much of Abiomed's research, cautioned that the trials are "a very small step" toward development of an artificial alternative to a heart transplant: "That's way off in the future," Watson said.
Lederman said the trial implants will cost $75,000, but the company hoped to reduce the price to $20,000-25,000 in the future.
The AbioCor, under development for more than 20 years, has two clear plastic yoyo-shaped chambers with a titanium housing joining them together like the filling in a cookie. Each chamber functions as a heart ventricle, while the metal housing contains an electrically driven centrifugal pump that pushes hydraulic fluid against soft plastic diaphragms facing each chamber. This alternating movement propels blood out of one chamber as it draws it into the other. The pump can alter its effort according to the patient's level of exertion, according to the manufacturer.
Past efforts to construct replacement hearts have had to solve two problems; clotting when blood corpuscles pile up on a device's sharp edges; and infection caused by the need to run wires and tubes in and out of the patient's body -- essentially servicing the device through an open wound.
A modified version of the Jarvik 7, with an incision, is being used with considerable success by patients for short periods of time as they await heart transplants. Last year Abiomed bought up its only competitor, Penn State Heart, based at Pennsylvania State University.
Researchers honed AbioCor's design in bench tests and by implanting the device in calves at Houston's Texas Heart Institute. And instead of tubes and wires, power to the device is delivered from a battery pack worn as an adjustable belt around the waist or held up by suspenders.
Energy is passed through the skin to an internal device that uses radio frequency from outside the body.
Each rechargeable battery lasts up to two hours. There is room for a spare battery that allows mobility for four hours. An internally implanted auxiliary battery, with a 30-minute power supply, is available for emergencies.
Because there are no wires or tubes, a patient using the device can take a shower and change clothes without the difficulty recipients of Jarvik-7 hearts had.
"This implantability is a major advance as far as artificial hearts go," said New York University Medical Center cardiologist Daniel Fisher. "It's a nice development, but I don't think it's the final step."
This, said Fisher and others, is because alternative technologies have left AbioCor in a dilemma as far as proving its effectiveness. Only people at death's door are eligible for implants, but if patients were in better shape, doctors would most likely use other technologies, especially implantable "ventricular assist devices" that help a damaged heart do its own work.
"With an (assist device), if there's a problem, the patient's heart is a backup," said Patrick McCarthy, director of heart transplantation at the Cleveland Clinic, which does between 30 and 50 assist device implants per year. "There is a lot of experience with therapies to improve a person's own heart. We don't particularly like to burn our bridges."
Famed Houston heart surgeon Michael DeBakey agreed that AbioCor would never be as useful as the assist device, which is "relatively simple, has less bulkiness of material, (and) requires less power."
But DeBakey credited the Abiomed team with a "very significant, very important development," because, for a small number of patients, an artificial organ is the only alternative.
Abiomed literature says that the potential market for AbioCorin the United States could be as large as 100,000 patients, but this is disputed by others who say that only a tiny percentage of those suffering from lingering heart disease could benefit.
Although heart transplants are extending the lives of many patients, there are 4,231 people on the transplant list in the United States, and only about 2,000 hearts become available in a year, according to the United Network for Organ Sharing, which coordinates transplants.
Jarvik said AbioCor was so large it would only fit in people who weighed close to 200 pounds, excluding almost all women and most men: "Many years of experience have taught us that cutting out the heart is unnecessary," said Jarvik, who, like DeBakey, has invented an assist device. "As a leader in total heart replacement, I have learned through all these years that (it) is not going to provide a public health benefit."
- Information from the Washington Post, New York Times and Associated Press was used in this report.
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Susan Taylor Martin
From the AP