THE first self-contained artificial heart has been given to a man in the US.
Its makers hope the device will help make up for the enormous shortfall in donor
organs.
Unlike previous devices powered by wires penetrating the skin, the heart,
along with a battery and controller, fits entirely inside the body. The
battery only lasts for 40 minutes, but it can be recharged through the skin
using induction. 鈥淥ur aim was that you鈥檇 be able to line recipients up with
other people and see no external difference,鈥� says Ed Berger, vice-president of
Abiomed of Massachusetts, which developed the $75,000 heart.
As 快猫短视频 went to press, the unnamed patient had been placed back on a
respirator after a seven-hour operation at the Jewish Hospital in Louisville,
Kentucky, although his surgeons Laman Gray and Robert Dowling from the
University of Louisville said it was not a major setback. It was a very
difficult operation because of the amount of scar tissue he had from heart
attacks and previous bypass ops鈥攚hich is why he was turned down for a
normal transplant. Like the four other patients who will be involved in the
first trials, he was expected to die within 30 days without treatment.
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The artificial heart weighs about a kilogram and consists of a motor that
drives a pump of membranes and valves made of a strong, flexible plastic
invented by the company. 鈥淚t has to flex over millions of cycles and be
compatible with blood, to avoid clotting,鈥� says Robert Kung, who invented the
device. The controller monitors blood pressure and speeds up or slows the heart
in response to, say, walking.
The trial was approved by the US Food and Drug Administration after extensive
tests in calves, which are still alive after a year. Unlike a transplant heart,
there is no chance of the body rejecting the artificial replacement, and the
patient doesn鈥檛 have to take immune suppressant drugs. Other researchers hope it
will be possible to transplant hearts from genetically modified pigs, or even
grow human hearts in the lab.