Plane technology for new heart
2008-10-30 08:41
London - 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 on Monday.
"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 €150 000 (R1.9m).
Previous artificial hearts have been unable to automatically vary their pumping speed and must be tweaked externally. The French heart is also the most lifelike, with two pumps to send the blood into the lungs and the rest of the body, just like a real heart. Past artificial hearts have only had one pump.
Natural materials
"This could be a bases-loaded home run if it works," said Dr 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.
In 2000, the Jarvik "heart," a pump that helped patients' hearts circulate blood, was first implanted into patients in the US.
Other artificial hearts have followed or are in the works. The American company Abiomed received approval in 2006 from the Food and Drug Administration for its artificial heart for use in dying patients with no other options. On average, it has extended patients' lives by about five months.
Scientists in Japan and South Korea are also working on artificial hearts.
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.
Heart disease is the world's top killer. According to the American Heart Association, about 2 200 heart transplants were performed in the US in 2006. Thousands more patients would benefit if more donor hearts were available.
French heart could last longer
Dr Ottavio Alfieri, a professor of cardiac surgery at Raffaele University Hospital in Milan and spokesperson for the European Society of Cardiology called the French artificial heart "a major advance." He was not connected to the project.
While previous artificial hearts have mainly acted to buy time until a real heart becomes available, Alfieri said that the French heart might work in the longer term.
Experts said that the artificial heart's design was promising, but 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 Dr Tim Gardner, president of the American Heart Association.
He said tests in humans would show how durable the device is, and determine the chances for complications.
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.
"Using an artificial heart will cause more stress on the patient than a donor heart because there is a lot of foreign material here," said Alfieri.
But he also 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 Dr Karl Swedberg, a cardiologist at the University of Gothenberg in Sweden. He doubted that 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.
- AP