NASA COMPUTER SCIENCE HELPS HEART PUMP TEAM WIN INVENTION OF THE YEAR
John Bluck
NASA Ames Research Center, Moffett Field, CA
Phone: 650/604-5026 or 604-9000
E-mail: jbluck@mail.arc.nasa.gov
RELEASE 02-36AR
NASA computer scientists were
significant contributors to the original NASA/DeBakey miniature
heart assist pump, an updated version of which was just named winner
of NASA's Commercial Invention of the Year Award.
Also known as a 'ventricular assist device' (VAD), the pump is currently
undergoing human trials with patients awaiting heart transplants.
It is based in part on technology used in space shuttle fuel and
oxidizer pumps. NASA computer engineers suggested improvements after
simulating blood flow through the pump using a NASA computer that
normally models the flow of fuel through rockets.
"Johnson Space Center and DeBakey Heart Center of Baylor College
of Medicine asked us to help them because of our experience with
simulating fluid flow through rocket engines," said Dochan
Kwak, chief of the NASA Advanced Supercomputing Applications Branch
at NASA's Ames Research Center in California's Silicon
Valley. He and colleague Cetin Kiris analyzed blood flow through
the battery-powered heart pump, whose blade normally spins as fast
as 10,000 rpm. "The speed of fluid flow through a rocket engine
is faster than blood flow, but very similar in many ways,"
Kiris noted.
MicroMed Technology, Inc., Houston, manufactures the pump, now called
the DeBakey VAD™. It is intended as a long-term 'bridge' to
a heart transplant, or as a long-term device to help patients move
toward recovery and a more normal life. In European trials, the
VAD was implanted in 115 people with no device failure. U.S. trials
will involve 178 implants; 21 have been performed successfully to
date.
During initial development of the one-inch by three-inch implantable
axial rotary heart pump, engineers noticed two major problems. Friction
led to damaged blood cells because the device created high shear
flows through pump parts. Further, there were stagnant regions in
the pump that caused blood clotting, a major problem with ventricular
assist devices.
Following supercomputer simulations, NASA computer scientists were
able to reduce red blood cell damage to an amount comfortably below
acceptable limits. The improved blood flow pattern also reduced
the tendency for blood clots to form.
"We worked with the team to make the blood flow more smoothly
through the pump; that also removed the stagnant regions,"
Kiris said. NASA Ames scientists first began assisting the NASA/Baylor
team in 1993, and continue to collaborate with them.
In keeping with its mission of transferring space-based technology
to the private sector, in 1996 NASA granted exclusive technology
rights to MicroMed Technology Inc. after a period of intense competition.
"Without the support of the NASA supercomputer design experts,
the pump would not function as efficiently as it has," said
Dallas Anderson, president and CEO of MicroMed.
Within two years of receiving the NASA license for the pump, MicroMed
gained international quality and electronic standards certifications,
got permission to begin clinical trials in Europe and implanted
the first device. The first patient, a 56-year-old man, received
the DeBakey VAD™ in November 1998, in Berlin. The pump functioned
normally and to its design specifications, Anderson said. The device
has been implanted for periods of up to one year in individual patients,
thus far.
"There are three groups who made this effort successful,"
Kwak said. "The medical team led by Dr. Michael DeBakey and
Dr. George Noon, the systems engineers at Johnson Space Center,
and the Ames computational team that used NASA supercomputer know-how
to help develop the VAD™."
The concept for the pump began years ago with talks between DeBakey
and one of his heart transplant patients, David Saucier, a NASA
Johnson engineer who passed away in 1996.
Six months after his 1984 heart transplant, Saucier was back at
work. With fellow NASA employees, as well as DeBakey, Noon and other
Baylor staff, Saucier worked evenings and weekends on the initial
pump design.
"Since my own transplant, I have spent a lot of time visiting
people who are waiting for a donor heart," Saucier said at
the time. NASA began funding the project in 1992.
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