Dennis, Clarence, 1909-2005

Dr. Clarence Dennis, pioneering heart surgeon and developer of a heart-lung bypass machine, was born to Dr. Wayne and Clara Dennis of St. Paul, Minnesota on June 16, 1909. A health condition prevented Dennis from serving in the military during World War II, so he remained at the University of Minnesota in a variety of instructional and professorial positions in the Department of Surgery. Under the tutelage of the chairman, Dr. Owen H. Wangensteen, Dennis developed an interest in cardiac surgery, particularly the idea of a mechanism to bypass some cardio-pulmonary functions. In 1946 Dennis visited Dr. John H. Gibbon at Jefferson Medical School in Philadelphia; Gibbon had been working on a pump-oxygenator since 1934. The two surgeons traded ideas over the next few years as Dennis began working on similar technology with funding from the National Institutes of Health (NIH). Over the next few years Dennis constructed various apparatuses to provide a suitable substitute for the heart and lungs. Inspired by the success of artificial kidneys, he developed a similar machine; however, it failed to provide enough oxygenation of the blood during bypass. By 1951, Dennis and his staff had developed a pump-oxygenator which led to successful operations on nearly two dozen dogs; this success gave Dennis the confidence to try his machine on a human subject. On April 5, 1951 Dennis, Dr. Richard Varco, and the University of Minnesota Hospital surgical staff performed the world's first open-heart surgery. The machine performed satisfactorily, but the young patient's heart defect proved to be much more severe than originally diagnosed, resulting in her death. In 1972 Dennis took over as Director of the Artificial Heart Program at the National Heart and Lung Institute (NHLI) at NIH. His main task was to study the feasibility of long-term usage of the artificial heart, resulting in a position paper for NIH. He argued in his paper that a lack of adequate staff numbers and expertise, coupled with advances in heart transplantation, would severely hamper the successful implementation of an artificial heart program.

From the description of Clarence Dennis papers, 1927-2003. (National Library of Medicine). WorldCat record id: 237191792

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