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In
the winter of 2001, FRONTIERS reported on a promising new,
self-contained artificial heart made by Abiomed. Since then,
the Abiomed heart has entered into human trials and, today,
shows some promise in helping the 700,000 Americans that die
from heart failure each year. In this segment, we recap the
long road that artificial heart research has traveled, and
the problems scientists still face in making this much-needed
device a reality.
It
was 1982 when Barney Clarke first made headlines as the recipient
of his artificial heart, the Jarvik 7. But when Clarke died
after four months and other implant attempts proved unsuccessful,
the device was abandoned. While researchers headed back to
the drawing board, a new invention entered the scene - the
"left ventricle assist device" or L-VAD. This mechanical pump
is implanted to help a weakened heart send blood around the
body, allowing a patient to buy crucial time while awaiting
a transplant. FRONTIERS met one such L-VAD patient in 1993,
Michael Dorsey, who today, having received his transplant,
is still going strong.
The
Abiomed heart, unlike the L-VAD but like the Jarvik 7, is
intended to replace an ailing heart permanently. But unlike
both devices, the Abiomed does not need tubes to penetrate
the skin, powered instead by a battery that's rechargeable
through the skin. As its developer David
Lederman tells Alan, one of Abiomed's chief concerns is
the prevention of deadly clots that can form as the blood
circulates through the device. But with its smooth surfaces
and two powerful pumping chambers, the Abiomed performed well
in its initial trials in animals.
By
spring of 2001, the Abiomed heart was ready for human trials
and Bob Tools was its first recipient. Once given only days
to live, the bed-ridden Tools was soon able to move about
and even go on a few short outings. Doctors then performed
four additional transplants with the new heart. Tools lived
for nearly five months, but eventually succumbed to a stroke.
To date, two patients are still alive, but there has been
one other fatal stroke. Abiomed is currently redesigning the
heart in an attempt to eliminate all potential clot-forming
parts. Implants for a further nine patients have been approved,
but are on hold.
For
more on this topic, see the web feature:
Searching for a Substitute
Artificial Alan

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