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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