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In Memoriam

Kenneth Clark Butler (1939–2018)

Borovetz, Harvey S.*; Antaki, James F.

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doi: 10.1097/MAT.0000000000000973
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ASAIO and the entire artificial organs community lost a truly remarkable inventor, visionary, colleague, and friend with the passing of Ken Butler on December 13, 2018 (Figure 1). Ken’s professional career, like the man himself, was remarkable. For 13 years, Ken was a project engineer/rocket scientist at Aerojet Liquid Rocket 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, where he and his team secured major government contracts for pioneering thermally-powered artificial hearts and left ventricular assist devices (LVADs). Together with their clinical partner, the Cleveland Clinic Foundation, they were contracted by National Heart Lung and Blood Institute (NHLBI) to develop an electro-hydraulic LVAD, a fully implantable LVAD, and a total artificial heart (TAH). Ken’s successes over the years in securing NHLBI grants and contracts paved the way for Nimbus’ clinical introduction of two breakthrough blood pumps that revolutionized the field of mechanical circulatory support (MCS): the Hemopump™ in 1988 and the “Axipump” which later became the HeartMate II (HM II) in 2003.

Figure 1.
Figure 1.:
Kenneth Clark Butler (1939–2018). Photo originally published on

Our “connection” with Ken Butler began for one of us (H.S.B.) in 1977 at the First Annual Contractors Conference sponsored by the Devices and Technology Branch of NHLBI. At that meeting, and subsequent Contractors Conferences, Ken reported masterfully on his thermal energy systems for MCS and TAH/LVAD technologies under development, which established him as one of the lead investigators in the field. It was also very obvious how respected and liked Ken was by all in the field, including his competitors for NHLBI funding in the TAH and LVAD programs.

In 1990, Dr. Bartley Griffith, then Chief, Division of Cardiac Surgery, Department of Surgery, University of Pittsburgh (UoP) wanted to expand UoP’s footprint in MCS beyond its clinical program. Being aware of Ken Butler’s aforementioned achievements in his LVAD/TAH programs, Dr. Griffith approached Ken about forming a partnership toward the development of axial flow blood pumps. One year later the Nimbus-UoP partnership was formalized and competed successfully for NHLBI Small Business Innovative Research awards that resulted in a scaled-up version of the Hemopump, then known as the “Axipump” or “Ax-LVAS” that was capable of providing full LV support for chronic use. Under Ken’s wonderful leadership, the Nimbus-UoP team also developed a small, centrifugal paracorporeal blood pump suitable for pediatric applications.

In 1994 the Devices and Technology Branch of NHLBI issued a Request for Proposals on the topic, “Innovative Ventricular Assist Systems (IVAS).” Ken was principal investigator on the successful application submitted by the Nimbus-UoP partnership.

After almost a decade of research and development, the final product of Ken’s IVAS contract, the HM II, was first successfully implanted in a patient in 2003 by Dr. O.H. Frazier. The enormous impact that HM II has had on the treatment of heart failure worldwide can be appreciated from the following statistics (as of December 22, 2017):

  • Patients implanted: >26,000 worldwide.
  • 2,325 patients on support for more than 5 years.
  • Forty-four patients on support for more than 10 years.
  • Age range: 10–91 years.
  • Transplanted, recovered, or supported to 6 months: 91%.
  • More than 1,000 publications on HM II.

Ken received numerous professional awards for his monumental contributions to the field of MCS. He was the recipient in 1994 of the HIMET Award for Outstanding Contribution to Advancement of Rotary Blood Pumps from the International Society for Rotary Blood Pumps (ISRBP). Ken was elected in 1996 to the College of Fellows, American Institute for Medical and Biological Engineering. Ken presented the prestigious ASAIO Hastings Lecture in 2001. He served as a Member of the Scientific Board of Directors of ISRBP from 1991 to 2004. Just this past year, Ken was nominated for the prestigious Russ Prize of the National Academy of Engineering that recognizes an “outstanding bioengineering achievement in widespread use that improves the human condition.”

To hear more about Ken’s remarkable professional career, in his own words, please refer to his ASAIO Pioneer Interview:

Above and beyond the technical breakthroughs, the business acumen and the impactful contributions to the field all noted above, Ken was a person who brought zest, enjoyment, and friendship to his colleagues, many of whom became his lifelong friends. Quoting Dr. Richard Wampler, Adjunct Research Associate Professor of Surgery, Oregon Health Sciences University, “I met Ken in 1981 when I was a BME masters student. He was at Aerojet working on NIH LVADs. … I worked very closely with Ken [at Nimbus Medical] for a very long time on the Hemopump and HM II. Ken believed in, and championed, rotary blood pumps and the Hemopump when very few people did. Ken led the successful effort to bring the HeartMate II to clinical success. He did this against, what I thought, were insurmountable odds. Fortunately, he proved me wrong. He was a man of substance, integrity, and humility. I will miss him.”

Victor Poirier, Chairman of the Board, Saints Medical Systems and Professor, University of South Florida, expresses similar sentiments, “I always respected Ken’s engineering prowess as well as his excellent team of engineers that he assembled in Nimbus, the company that he co-founded. He was always a fierce competitor who carried himself with professionalism. We both saw the benefit of joining forces, Nimbus and Thermo Cardiosystems (TCI)—which occurred in the mid-1990s, to bring HM II to the clinic. Working with Ken was always a joy. In the 35 years that I knew Ken, I have never heard any negative comments about him, only praise for his enthusiasm, good nature and engineering talent. He was a wonderful individual loved by all. We will miss him; a great colleague and friend.”

Dr. David Farrar, Director, Research and Scientific Affairs, Abbott and another longtime colleague notes, “I had great respect for Ken and enjoyed very much working with him. We worked closely with Ken and his team on transferring the HeartMate II from R&D and the pre-clinical world into manufacturing and a successful series of clinical trials leading to commercial approvals in the EU and US. It is appropriate that Ken is affectionately known as the father of the HeartMate II. With over 26,000 implants, many with 5+ and even 10+ years of support, there is a large admiring family of thankful recipients who owe a debt to ‘father Ken.’ We are all grateful for his contributions to this device and to the field. He is greatly missed as a friend and colleague.”

Dr. John Watson, who as Chief, Devices and Technology Branch, NHLBI from 1976 to 1994 and Head, Artificial Heart Program from 1976 to 2003 directed NHLBI funding on behalf of Ken’s many grants and contracts, comments, “Ken had a profound effect on our community of colleagues and by his works … the World. He was a beacon of light personally and professionally. Leading the creation of the HM II brought his light to shine on and open the field of Assisted Circulation to clinical practice.”

When asked to provide a quote about Ken, Dr. John Woodard, CTO—Berlin Heart GmbH responded, “My favourite quote from Ken Butler was when Ken and I were at the Smithsonian Air and Space Museum in the Apollo moon mission area: ‘Look up there, that’s my fuel pump,’ said Ken. The pump in question was a 50,000 brake horsepower liquid oxygen turbopump … I will always remember Ken as one of the most enthusiastic and affable characters who had so much to be proud of.”

We cannot conclude the In Memoriam without mentioning Ken’s deep love of family; his wonderful companion following the passing of his beloved wife Barbara, Linda Moise; Ken’s love of woodworking and building furniture for his grandchildren; his daily routine of early morning workouts with his friends that brightened their day. Ken had a deep affection for Napa Valley (where he was born and raised), and he derived such pleasure each-and-every time he and Barbara would host a Sunday outing for both of us (H.S.B. and J.F.A.) at Vallejo. These Sundays would be spent in the most enjoyable conversation in a small park adjacent to the tracks of the Wine Train, consuming wine and delicious delicacies Ken purchased at the Oakville Grocery and Salami Barn.

Ken Butler was a “mensch” in the very best sense of the word; a totally genuine person through and through who put everyone ahead of himself. The outpouring of sadness and fond remembrances of Ken since his passing reflect not only his exceptional professional contributions, but also even more importantly the wonderful person he truly was. ASAIO and all of us were blessed to know Ken, work with Ken, learn from Ken, and be a part of his life. While he will be sorely missed, we can take solace in the fact that Ken’s contributions have improved the lives of thousands and will continue to do so in the years ahead.

In Memoriam 2018

The artificial organs community lost several pioneers in 2018. Dr. Theodor Kolobow (1931–2018) invented the spiral coil membrane lung and made considerable contributions to the extracorporeal life support (ECLS) field. Dr. Kolobow was the subject of a Pioneer Profile published in the March–April 2016 issue of ASAIO Journal.

Dr. Donald Olsen (1930–2018) was the co-inventor of the artificial heart. A remembrance of Dr. Olsen’s life and work will be delivered at the 65th annual ASAIO conference in San Francisco, California, in June.

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