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Clarence Dennis Edit Profile

educator , Surgeon

Clarence Dennis, American surgeon, educator. Diplomate American Board Surgery. Recipient Modern Medicine award for distinguished achievement, 1973, John H. Gibbon award American Society Extracorporeal Technicians, 1974, dedication Forum on Fundamental Surgical Problems, American College of Surgeons, 1987.


Dennis was born in St. Paul, Minnesota on June 16, 1909, the son of Warren, a surgeon, and Clara Van Orman Dennis.


Bachelor of Science, Harvard University, 1931; Doctor of Medicine, Johns Hopkins University, 1935; Master of Science, University of Minnesota, 1938; Doctor of Philosophy, University of Minnesota, 1940; Doctor of Science (honorary)., SUNYHealth Science Center, Brooklyn, 1988.


He had invented one of the first heart-lung bypass machines, and in 1951 he became the first to use such a device during an open-heart operation. Dennis enjoyed research as much as the operating room. Meanwhile, Dennis began work on his pump-oxygenator in 1946.

He met with John Gibbon, the person who would later perfect cardiopulmonary bypass. In 1951, the first attempt with CPB was attempted on humans with Dennis at the helm. The patient was a 6-year-old girl, dying from a congenital heart defect.

The heart-lung machine worked well for the first 40 minutes, but the heart defect was unrepairable and the patient died. The second use of the machine was futile as well, this time due to a technician error. He would perform no further cases at the University of Minnesota.

Dennis was recruited to SUNY Downstate Medical Center in New York later in 1951 to chair the department of surgery. There, he and his team eventually performed their first successful operation using the heart-lung machine in 1955. As chair, he helped build the department, including the addition of residency and research programs.

He pioneered cardiopulmonary bypass to in patients with cardiac shock following myocardial infarction. After more than twenty years at SUNY, Dennis left in 1972 and went to work at the National Institutes of Health in Bethesda, MD. In 1975, Clarence Dennis was appointed to the faculty of SUNY Stony Brook, remaining there until his retirement in 1988. He moved back to St Paul in 1991, and directed the University of Minnesota's Cancer Detection Center, originally founded by Owen Wangensteen, the person who initially assigned Dennis the task of creating a pump oxygenator in the 1930s.

He died on July 11, 2005 at the age of 96, from complications arising from dementia in his hometown of St. Paul, Minnesota.


  • In 1996, Dennis announced his retirement at the age of 86, feeling that his macular degeneration and advanced age were preventing him from accomplishing several worth-while publications to the scientific literature.


  • Other Work

    • Contributor articles to professional publications and textbooks.


Fellow American College of Surgeons (past governor, dedication The Forum Volunteer 1987). Member Association Advancement Medical Instrumentation (president 1980-1982, chairman board 1982-1984, Laufman-Greatbatch award for contributions to instrumentation 1984), American Heart Association, American Society for Artificial Internal Organs (past president), International Surgical Society (past president United States chapter), Society Vascular Surgery (past president), New York Surgical Society (past president), Brooklyn Surgical Society (past president), American Association Surgery Trauma, American Association Thoracic Surgery, Society University Surgeons, American Surgical Association (past vice president), Society Clinical Surgery, Society Experimental Biology and Medicine, New York Cancer Society (past president), International Cardiovascular Society, Society Surgery Alimentary Tract, National Society Medical Research (president 1977-1979), New York Society Thoracic Surgery, Society University Surgical (past secretary), Foundation biomedical Research (board directors 1989-2005).


Married Eleanor Mary Smith, June 17, 1939. Children: Jane E. Dennis Wigertz, Richard, James, David. Married Mary Elise Mott, March 12, 1977.

Stepdaughter, Katherine Elise Franda.

Warren Arthur Dennis

Clara May (Van Orman) Dennis

Eleanor Mary Smith

Mary Elise Mott

Richard Dennis

Jane E. Dennis Wigertz Dennis

James Dennis

David Dennis