Would Improve Recipients’ Quality of Life : Battery-Powered Heart on the Horizon
BOSTON — A biotechnology company is developing a permanent, implantable, battery-operated artificial heart, and it is hoped that the device will allow patients to lead more normal lives than earlier artificial hearts.
The new heart is designed to give patients greater freedom than previous artificial hearts because it will be powered by an internal, rechargeable battery rather than attached to a bulky, external power source.
“The other artificial hearts, in particular those that have been used in human experiments, are systems where the blood pump is inside the body, but the drive is outside,” said David M. Lederman, chief executive officer of AMBIOMED Inc., a Danvers, Mass., biotechnology company developing the heart.
“An artificial heart as a therapy makes sense only if one can provide reasonable quality of life. And reasonable quality of life means the patient needs to resume near-normal activities. To do so the patient needs to be totally ambulatory,” he said.
Made of Advanced Plastics
The heart, which will weigh about two pounds and be made from advanced plastics and metals, will be implanted into the cavity where the natural heart had been.
A battery about the size of two packs of cigarettes and a miniature computer to control the heart will be implanted in the patient’s abdominal area and attached to the heart with an internal wire.
The patient will wear another battery, about four times the size of a pack of cigarettes, on a belt or a shoulder bag attached to a device known as a “skin transformer.”
The transformer will sit against the outside of the patient’s abdominal area and send power through the skin, without piercing it, to keep the internal battery charged. The external battery will be able to keep the heart running at normal capacity for about 10 hours without being recharged, Lederman said.
Previous hearts that have been implanted in humans have had tubes coming through the skin to air pumps that provided power. The tubes have been the source of infections.
The new heart is also being designed to reduce the chances that potentially deadly blood clots will form, causing strokes and organ damage, Lederman said.
All the heart parts that come in contact with blood will be made of a material known as Angioflex, a plastic that minimizes the chances of blood clots developing, he said.
Made From Single Material
“One of the main features of our system is the entire blood pump, including the valves, is made from a single material, so from the time the blood enters the heart it does not see any other material,” he said.
The technology was first developed for the company’s permanently implantable left ventricular assist system, a device that works in parallel with the patient’s heart rather than as a replacement. That device is being tested at the Massachusetts General Hospital in Boston.
The company recently received a $5.6-million grant from the National Heart, Lung and Blood Institute to pay for five years of development and initial testing on the new heart at the Texas Heart Institute in Houston. It will probably take several years of additional work before the device is ready to be tested on humans, Lederman said.
“I am optimistic. I am convinced we will have artificial hearts that provide reasonable quality of life. But I am realistic, and I know it will take time,” he said.
Between 17,000 and 35,000 patients in the United States each year are estimated to need permanent heart replacements. But there are only several thousand human hearts available each year for transplantation.
