Maria Chen , The Associated Press , London | Wed, 11/12/2008 12:15 PM | Life
The prototype of a fully implantable artificial heart is seen at the biomedical firm Carmat in Suresnes, west of Paris. The prosthetic heart, which has been successfully tested on animals, is ready to be manufactured and could be tested on humans within 1The prototype of a fully implantable artificial heart is seen at the biomedical firm Carmat in Suresnes, west of Paris. The prosthetic heart, which has been successfully tested on animals, is ready to be manufactured and could be tested on humans within 18 months to two years. (AP/Jacques Brinon)
In the race to create the world’s first fully functioning artificial heart, French scientists have turned to technology from satellites and airplanes.
The new heart could save millions of lives if it works in humans. So far, it has only been tested in animals. The device was unveiled at a press conference in Paris recently.
American companies have already produced artificial hearts, and scientists in Japan and South Korea are also working on versions.
But the French artificial heart is the first to be able to determine its patients’ needs and respond accordingly.
“It’s the same principle in the airplane as in the body,” said Patrick Coulombier, chief operating officer of Carmat, the heart’s manufacturer, a subsidiary of the European Aeronautics Defence and Space agency, makers of the Airbus plane.
Coulombier said the same tiny sensors that measure air pressure and altitude in an airplane or satellite are also in the artificial heart, detecting things like the heart’s pumping speed and the pressure on its walls.
That should allow the device to respond immediately if the patient needs more or less blood.
The heart is expected to cost about US$192,140. The most advanced U.S. artificial heart, made by the U.S. company Abiomed, sells for up $250,000.
Abiomed was aware of the French project but said it was ahead in the race.
“Our artificial heart has already been implanted in patients and is FDA-approved,” said Aimee Maillett, a com-pany spokeswoman. On average, Abiomed’s heart has extended patients’ lives by about five months.
Few details are available about the artificial hearts being developed in Japan and South Korea because the scientists have not published their work widely.
Previous artificial hearts have been unable to automatically vary their pumping speed. The French heart is also the most lifelike, with two pumps to send blood into the lungs and the rest of the body, just like a real heart. Past artificial hearts have only had one pump.
The heart was tested in sheep, but scientists did not test how long it would keep the animals alive. Laboratory experiments tested the heart in various scenarios, including, for example, when a hypothetical patient was exercising and suddenly needed more blood.
“This could be a bases-loaded home run if it works,” said Douglas Zipes, past president of the American College of Cardiology and professor of cardiology at Indiana University. Zipes was not linked to the French research.
The French model is made from natural materials including polymer and pig tissue, which have already been used in heart valves implanted into people.
Those have not caused any problems like rejection or clotting, commonly seen with artificial hearts or devices. That makes some doctors optimistic that a heart partially constructed from the same tissues could spare patients lifelong anti-rejection and anti-clotting medicines.
The artificial heart would initially be for patients who had suffered a massive heart attack or who had heart failure, but might eventually be used in patients were are not that sick. French doctors hope to start tests in humans in the next two years.
Heart disease is the world’s top killer. According to the American Heart Association, about 2,200 heart transplants were performed in the U.S. in 2006, and the waiting list is long.
While previous artificial hearts have mainly acted to buy time until a real heart becomes available, Dr. Ottavio Alfieri, a professor of cardiac surgery at Raffaele University Hospital in Milan and spokesman for the European Society of Cardiology, said the French heart might work in the longer term.
Experts warned that many past attempts to replace the human heart have failed.
“Virtually all devices that have been implanted in humans, no matter how well designed, have been associated with unforeseen complications,” said Tim Gardner, president of the American Heart Association.
In recent years, heart doctors have questioned the popularity of drug-coated stents used to prop open arteries. Several studies have linked the tiny mesh-metal stents to fatal blood clots, leading some doctors to scale back on their use.
With problems in using such tiny devices, some experts wonder about the impact of an entire artificial organ in the body. But Alfieri said that, since the artificial heart was essentially a pump, it would not be releasing any drugs like the drug-coated stents and might be less problematic.
Others were more wary.
“This is a high-risk area with a lot of problems,” said Karl Swedberg, a cardiologist at the University of Gothenburg in Sweden. He doubted the new artificial heart could be used to alleviate the shortage in donors, since it was very expensive and would still require a major operation.
“An artificial heart is an interesting idea, but we should focus on the established treatments we already have,” Swedberg said.
