U.S. Gives Up on Developing Complete Artificial Heart
The government’s National Institutes of Health is giving up on efforts to develop a total artificial heart and will concentrate on smaller, less-complex pumps that assist rather than replace ailing hearts.
Dr. Claude Lenfant, director of the National Heart, Lung and Blood Institute, said Thursday that the agency has decided that replacing the heart totally with an artificial device “still has a lot of problems” that will not soon be solved.
He said that in every application of an artificial device for total heart replacement the patients have died either of infection or stroke caused by blood clots that develop within the synthetic heart.
“Those issues have not been resolved,” Lenfant said in an interview.
NIH has given a total of $2.7 million in research grants on the total-heart replacement this year, but Lenfant said that will be the last. Since 1964, the agency has spent $239.31 million on various elements of artificial heart development technology.
Now, Lenfant said, the agency will support only four grants for the development of a self-contained, long-term “single-ventricular” device. This would be inserted into the left ventricle of the heart, the chamber that endures most of the work stress in the four-chambered human heart.
Viewed as Practical
“We believe there can be an extremely reliable single-ventricle system developed for clinical application,” Lenfant said.
The single-ventricle device already has been used in more than 170 cases as a “bridge to transplant,” but it has not been implanted for long-term use, he said.
John W. Wood Jr., president of Thermedics Inc. of Woburn, Mass., said his company now has a long-term device being tested in experiments with animals. Thermedics is one of the four recipients of grants.
He said the device, which is an electrically driven, diaphragm-like pump called the Heartmate, is inserted into the left ventricle of the heart and powered by a battery.
Wood said the device has been tested successfully on calves and that application has been made for clinical trials.
A second assist device, designed to be used only temporarily, is currently on the market. This device is inserted to assist the heart only until the heart has recovered from trauma or until a donor heart can be found.
Lenfant said the total artificial heart replacement has been attempted five times worldwide, but none were considered successful.
The Jarvik-7 artificial heart was the most widely used in the United States. Barney Clark received the first artificial heart on Dec. 2, 1982. His University of Utah surgeon was Dr. William DeVries. Clark died in March, 1983.
DeVries could not be reached for comment Thursday.
William Schroeder, who received his artificial heart at the Humana-Audubon Hospital in Louisville, Ky., where DeVries now practices, lived longest with the Jarvik device--almost two years.
Lenfant said the Jarvik device was successful mechanically, but “the interface with the body was never successful.”
He said tubes leading to the outside may have contributed to the infections that killed some of the patients and the pump itself led to blood clots that causes strokes.
At the University of Utah, which had received one of the NIH artificial heart research grants, Dr. Donald Olsen told the Atlanta Constitution that cancellation of the research contracts “is a tremendous setback for scientific advancement in the field.”
The four firms that will receive grants for continued study of the heart-assist device are Thermedics, Abiomed of Danvers, Mass., Nimbus Medical Inc. of Rancho Cordova, Calif., and Novacor of Oakland.
Figures on the heart-assist device research grants were not immediately available from NIH, but Wood said his company was receiving a four-year grant of $6.4 million for testing of the device and $1.2 million for development of sub-assemblies that would be made available to the other companies.
