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ABOUT MY WORK WITH THE GREAT ROCKET ENGINEER
AND INVENTOR OF THE FIRST MICRO-TURBINE ARTIFICIAL HEART, KENNETH CLARK BUTLER (1939–2018)

“Ken’s professional career, like the man himself, was remarkable. For 13 years, Ken was a project engineer/rocket scientist at Aerojet Rocketdyne Company (Rancho Cordova, CA), responsible for developing the main engine for the Saturn V rocket that sent three Apollo astronauts to the moon.   This is where he developed his acumen in turbo-pump design and led him to become project engineer for the Artificial Heart Team at Aerojet.   In 1982 Ken and members of his team formed Nimbus Inc. in Rancho Cordova, California”

From a Memoriam published in the  
Journal of the American Society of Artificial Internal Organs
by Dr. Harvey Borovetz and Dr. Jim Antaki.

ABOUT MY WORK WITH KEN BUTLER

I met Ken in 1991.   We were introduced by the Distinguished Professor of Bioengineering Dr. Harvey Borovetz.   Harvey and his team started working with me in 1990 in my Particle Flow Research Laboratory at the USDOE Pittsburgh Energy Technology Laboratory.   We solved a blood clotting problem in an artificial heart, the Novacor Left Ventricular Assist Device (LVAD), that was causing strokes and fatalities in patients at three major US hospitals (Presbyterian Hospital in Pittsburgh; St Louis University Medical Center and Stanford Medical Center).

I’d invented and patented an imaging technology to visualize and measure the flow of blood cells in artificial hearts and lungs ( United States Patent 5,333,044A ).

Ken invented and patented ( United States Patent S5588812A ) the first micro-turbine blood pump in the world: The Nimbus Axi-Pump .   He wanted me to apply my Fluorescent Image Tracking Velocimetry (FITV) technology to study the flow of blood cells through his Nimbus AxiPump.   In the photo to the left, taken in my lab in 1992, I am holding the first prototype version of Ken Butler’s Nimbus AxiPump.

MY PUBLICATIONS ON THE DEVELOPMENT OF
THE ORIGINAL AND ADVANCED VERSIONS
OF KEN BUTLER’S NIMBUS AXIPUMP

Development of an Axial Blood Flow Pump Left Ventricular Assist Device ,   by Kenneth C. Butler ¹ , Timothy R. Maher ¹ , Harvey S. Borovetz ² , Robert L. Kormos ² , James. F. Antaki ² , Marina. Kameneva ² , Bartley. P. Griffith ² , Timothy. Zerbe ² , and Franklin Shaffer ³ , Journal of the American Society of Artificial Internal Organs, Vol. 38, No.3, M296 – M300, July 1992

1. Nimbus, Incorporated, Rancho Cordova, California
2. Artificial Heart and Lung Program, University of Pittsburgh, Pittsburgh, Pennsylvania
3. United States Department of Energy, Pittsburgh, Pennsylvania

Fluorescent Image Tracking Velocimetry of the Nimbus Axipump , by J. Kerrigan ¹ , F. Shaffer ² , T.R. Maher ³ , T.R. Dennis ³ , J. Tammy ³ , H.S. Borovetz ¹ , and J.F. Antaki ¹ ,   Journal of the American Society of Artificial Internal Organs, ASAIO Journal Volume 39, Number 3, pages M639-M643, July 1993.

1. Artificial Heart and Lung Program, University of Pittsburgh, Pittsburgh, Pennsylvania
2. United States Department of Energy, Pittsburgh, Pennsylvania
3. Nimbus, Incorporated, Rancho Cordova, California

High Speed PIV of Flow Fields in An Impeller Driven Respiratory Assist Catheter ,   Franklin Shaffer ¹ , Nathan Moore ² , Balaji Gopalan ¹ , William J. Federspiel ² and Greg Burgreen ³

1. National Energy Technology Laboratory, U.S. Department of Energy, Pittsburgh, PA
2. Medical Devices Lab, McGowan Institute for Regenerative Medicine, Pittsburgh, PA
3. Center for Advanced Vehicular Systems, Mississippi State University, Starkville, MS

Quantitative Measurement of Flow Fields in a Miniature Axial Blood Flow Pump using Fluorescent Image Tracking Velocimetry , by J. Kerrigan ¹ , J. Antaki ¹ , J. Maher ² , H. Borovetz ¹ , K. Butler ² and F. Shaffer ³ , ASME Fluids Engineering Division Meeting, Symposium on Laser Anemometry, Lake Tahoe, Nevada, June 1994

1. Artificial Heart and Lung Program, University of Pittsburgh, Pittsburgh, Pennsylvania
2. Nimbus, Incorporated, Rancho Cordova, California
3. United States Department of Energy, Pittsburgh, Pennsylvania

An implantable axial flow blood pump , Timothy R. Maher ¹ , Kenneth C. Butler ¹ , Bartley P. Griffith ² , Robert L. Kormos ² , P. Litwak ² , Marina V. Kameneva ² , Franklin D. Shaffer ³ , Harvey S. Borovetz ² , John P. Kerrigan ² and James F. Antaki ² , Abstracts American Society of Artificial Internal Organs, 23:47, 1994.

1. Nimbus, Incorporated, Rancho Cordova, California
2. Artificial Heart and Lung Program, University of Pittsburgh, Pittsburgh, Pennsylvania
3. United States Department of Energy, Pittsburgh, Pennsylvania

THE MEGENTA MEDICAL ELEVATE pLVAD,

AN ADVANCED VERSION OF KEN’S NIMBUS AXIPUMP

In 2021, thirty years after I designed a flow visualization system for Ken Butler’s Nimbus AxiPump in 1991, I designed a flow visualization system for a highly advanced version of Ken’s Nimbus AxiPump: The Elevate™ pLVAD (percutaneous Left Ventricular Assist Device).   The Elevate pLVAD is being developed by Magenta Medical of Kadima, Israel.

The Elevate pLVAD is the smallest heart pump in the world.  

It is a low-profile, high-flow arterial pump intended for temporary support of patients undergoing high-risk coronary interventions and for the treatment of patients admitted with cardiogenic shock.

The Elevate pLVAD shrivels for insertion to fit through a vein.   When in the left ventricle, the pLVAD expands into a micro turbine pump spinning at 24,000 RPM.  

In May of 2023, Magenta Medical received $55 million dollars in private-sector funding to advance the clinical programs of the Elevate LVAD in the United States towards FDA approval.

My report on my design of a flow visualization system
for the Magenta pLVAD

NEW: https://onlinelibrary.wiley.com/doi/abs/10.1111/aor.14991

THE MICROTURBINE IN THE HATTLER RESPIRATORY CATHETER

 Click to watch video

Using the flow visualization technology I invented and patented to visualize and measure blood flow driven by a 5 mm diameter micro-turbine in the Hattler Respiratory Catheter.   The micro-turbine is spinning at 5000 RPM.
High speed video was taken at 7300 frames/sec.

  The Memoriam of Ken written by our colleagues Dr. Harvey Borovetz and Dr. Jim Antaki is published in the
Journal of the American Society of Artificial Internal Organs,
Number 65, Volume 3, pages 301-302