September 25, 1996
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HERSHEY WINS NEW ARTIFICIAL HEART CONTRACT
HERSHEY, PA-- Penn State's electromechanical artificial heart will beat inside a human chest by the end of the decade, according to researchers at Penn State's Milton S. Hershey Medical Center. The device is expected to save thousands of lives when it becomes available.
Last year 770 patients across the country died while waiting for a heart transplant. Patients requiring a heart replacement, as many as 50,000 per year, could be implanted with the artificial heart, according to principal investigator Gerson Rosenberg, Ph.D.
"The Penn State device is the culmination of a number of years of cooperative research performed by physicians, engineers and veterinarians-- both at University Park and here at Hershey Medical Center," said William S. Pierce, M.D., professor of cardiothoracic surgery and director of surgical research at Hershey.
"A very experienced team that has been in place since 1970 is doing all the preclinical studies to bring the electromechanical artificial heart to the point where we can apply to the Food and Drug Administration in the year 2000 for permission to test the device in humans," said Pierce.
According to Pierce, the device is expected to be widely available five years after that, by the year 2005.
Clearly, the need for hearts is far greater than the availability of donor organs. Last year 44 patients died at eastern Pennsylvania hospitals while waiting for a donor heart, according to Kevin Sparkman of the Delaware Valley Transplant Program. As of July of this year, 3,648 patients are on the national waiting list for hearts, 175 of them in the Eastern half of Pennsylvania, said Sparkman.
Of the 50,000 requiring a heart transplant, only some three to four thousand qualify as candidates for transplant, according to Rosenberg.
The Penn State group began developing artificial hearts and related devices in 1970 and is considered a world leader in the field.
Calves are the current test subjects for the device which is a completely implantable total electric artificial heart. The device is designed for five-year reliability and is expected to allow a human patient to lead a relatively normal lifestyle. Five calves have now lived more than 100 days with the device; one lived for 160 days.
According to Pierce, the device was developed at the medical center and turned over to an industrial partner, the 3M Health Care company, for manufacture and assembly.
The Texas Heart Institute, which has been collaborating with the industrial partner Abiomed for several years, continues to develop their electrohydraulic artificial heart and is the only other institution under federal contract to develop an artificial heart.
Both teams, Penn State and The Texas Heart Institute, will test hermetically sealed systems in in-vitro test chambers over a two-year period to demonstrate long term reliability of the device, according to the funding agent, the National Heart, Lung and Blood Institute (NHLBI), an agency of the National Institutes of Health.
The air-driven Penn State Heart is one of only two artificial hearts approved by the FDA for use in humans as a temporary bridge to a heart transplant.
The electric artificial heart system consists of a compact electric motor-driven artificial heart, an implanted electronic control system, a device for transmitting power across intact skin and a shoulder-bag battery pack.
Two plastic pumping chambers with polyurethane blood sacs replace the patient's natural left and right ventricles. The upper portion of the patient's heart, the left and right atria, remain intact to act as holding chambers for the blood, much as they do for the natural ventricles. A tiny electric motor and a small mechanism called a rollerscrew push flat plates against the sacs to pump the blood. Artificial heart valves--such as those commonly used to replace diseased valves--direct blood flow.
The electronic system controls the electric motor and blood flow according to the system's assessment of the body's needs. Blood flow requirements, for example, would be different when a person is exercising or sleeping.
The patient carries or keeps a battery pack nearby with two identical batteries each able to power the system for roughly four hours. The battery pack can also be plugged in to an outside power source, though most patients, the researchers suggest, might use this option only when sleeping.
Energy from the battery pack passes radio-frequency current through a ring-shaped coil placed over the skin. An implanted coil receives the energy, providing power for the heart.
The wireless system includes the ability to pass information back and forth between the implanted heart and the outside. Detailed diagnostic information is available to researchers and physicians, and the various manipulations now done on the natural heart by drug therapy can be made by changing settings on the implanted control system.
The second phase of the contract with the NHLBI is for $7.7 million, the largest federal award to be received by Penn State's Milton S. Hershey Medical Center. The second phase of the contract with NHLBI is based on progress made in the first phase, 1993-96, during which the university received $6.2 million. It brings the total federal contract to $13.9 million over seven years of research and development.