Cooley, Denton Arthur (1920–2016)

By: Heather Green Wooten

Type: Biography

Published: November 11, 2020

Updated: November 11, 2020

Denton Arthur Cooley, pioneering heart surgeon and founder of the Texas Heart Institute, was born in Houston, Texas, on August 22, 1920, to Ralph Clarkson Cooley, a prominent Houston dentist and Mary Augusta (Fraley) Cooley. His grandfather, real estate developer and Houston businessman Daniel Denton Cooley, played a primary role in founding the Houston Heights district, a major suburb established in 1890. Cooley grew up in the Montrose section of Houston and attended Houston public schools—Montrose Elementary, Sidney Lanier Junior High School, and San Jacinto High School, where he excelled in academics and basketball.  He was also a proud contributor to the high school newspaper, the Campus Club until the end of his life.

Upon graduation from high school in 1937, Cooley enrolled at the University of Texas at Austin on a basketball scholarship. At 6 feet 4 inches tall, he played for the Longhorns as a forward and sometimes center. He was a member of the UT team that won the Southwest Conference Championship in 1939. During his sophomore year, Cooley joined Alpha Epsilon Delta, the premedical/predental honor society. In 1941 he received a B.A. degree in zoology. He graduated from the university Phi Beta Kappa and with highest honors.

His zoology degree led Cooley to enroll at the University of Texas Medical Branch at Galveston in 1941. After two years of study, he transferred to Johns Hopkins University School of Medicine in Baltimore where he graduated in 1944 with highest honors and Alpha Omega Alpha. As a surgical trainee at Johns Hopkins, Cooley began a close relationship with Alfred Blalock, chairman of surgery at Hopkins. Cooley witnessed Blalock perform in November 1944 the first “blue baby” operation, a surgical procedure to correct a congenital heart defect on a baby. Cooley completed a six-year surgical residency under Blalock and took a two-year military leave of absence in 1946 to serve in the Army Medical Corps in the 124th Station Hospital in Linz, Austria, where he was appointed chief of surgery. He was promoted to the rank of captain the following year.

Upon discharge from the military, Cooley returned to Baltimore in 1948 to complete his residency in general and thoracic surgery. While there, he met Louise Goldsborough Thomas, the head nurse on Halsted 5, the main surgical floor of Johns Hopkins Hospital. The couple married at the Evangelical Reformed Church in Frederick, Maryland, on January 15, 1949. Their first child, Mary Fraley Cooley, was born in 1950. Four additional daughters followed: Susan, Louise, Florence, and Helen.

Upon completion of his residency, Cooley sailed on the Queen Elizabeth for England where he spent a year at the Royal Brompton Hospital in London under the tutelage of Lord Russell Brock, a preeminent British chest and heart surgeon and pioneer in open-heart surgery.  As senior surgical registrar at Brompton, Cooley undertook the extremely long patient waiting list by performing twice as many operations per day as his contemporaries.

In 1951 Cooley returned to Houston at the invitation of Michael DeBakey to join the medical faculty of Baylor College of Medicine as assistant professor and to work at Methodist Hospital. Over the following years Cooley and DeBakey collaborated on a series of surgical breakthroughs, including work on cardiopulmonary bypass, artificial heart valve surgery, aortic rupture, surgical repair of aortic dissection, and coronary artery bypass grafting. In 1954 Cooley extended his practice to include Texas Children’s Hospital and St. Luke’s Episcopal Hospital. Soon after joining these institutions, he fabricated an early cardiopulmonary bypass machine that enabled complex cardiothoracic procedures to be performed in Houston. In 1962 Cooley founded the Texas Heart Institute (THI) at St. Luke’s Episcopal Hospital. Cooley asserted that the outcome of a surgery was related to its length and became known for his exceptional speed, manual dexterity, and technical expertise in the operating room. At his peak, Cooley, using an assembly-line approach, performed many operations a day.

In 1968 Cooley performed the first human heart transplant in the United States. The patient was Everett Thomas, a forty-seven-year-old accountant whose heart had been severely damaged by a bout of rheumatic fever. On April 4, 1969, Cooley performed the first human implantation of a total artificial heart on forty-seven-year-old Haskell Karp, who was suffering from severe heart failure. The artificial heart beat in Karp’s chest for three days until it was replaced by transplant of a donor heart. Cooley’s decision to implant the device led to a decades-long dispute with the principal investigator of the implantable heart, Michael DeBakey. The surgeons reconciled publicly in 2007 when DeBakey was ninety-nine years of age and Cooley was eighty-seven. 

In late 1969 Cooley resigned from his position as professor of surgery at Baylor College of Medicine and focused his attention on developing the Texas Heart Institute. He served as THI surgeon-in-chief for more than forty years. By the end of his career, Cooley and his team had performed more than 120,000 open-heart operations. In addition to his surgical success, Cooley pioneered the development of multiple procedures geared toward the repair and replacement of diseased heart valves. In 1971 he founded the Cullen Cardiovascular Surgical Research Laboratory, geared toward the development of mechanical circulatory assist devices. He also gained widespread recognition for his creation of innovative surgical treatments of cardiac anomalies in infants and children. He continued operating until he was eighty-seven years old and made rounds and visited patients until he was ninety-six.

During his career, Cooley authored more than 1,400 scientific papers and twelve books, including his autobiography 100,000 Hearts: A Surgeon’s Memoir in 2012. He was a member or honorary member of more than thirty professional societies around the world and a dozen fraternities and clubs. He served as president of the Johns Hopkins Medical and Surgical Association (1969–70) and was a member of the Johns Hopkins University Board of Trustees (1981–87). He also served lengthy terms on the development board of the University of Texas at Austin and the board of directors for the UT Texas Cowboys. His guiding principle was “modify, simplify, and apply.” This became the motto of the Denton A. Cooley Cardiovascular Surgical Society founded by his trainees in tribute to their mentor. As of 2020 the society boasted more than 850 physician members throughout the United States and the world. Among his numerous honors, Cooley received the Rene Leriche Prize, the highest honor awarded by the International Surgical Society (1967); the Presidential Medal of Freedom from President Ronald Reagan (1984); the National Medal of Technology and Innovation from President William Jefferson Clinton (1998); and the Theodore Roosevelt Award bestowed by the National Collegiate Athletic Association to a varsity athlete who achieved national acclaim in his profession. In 2010 Cooley received the American Surgical Association Medallion of Scientific Achievement for “Distinguished Service to Surgery.” He was named Honorary Fellow of five Royal Colleges of Surgery and received decorations from eleven foreign countries. 

Throughout his life, Cooley supported civic and humanitarian causes. Facilities that bear his name include the Student Center at Johns Hopkins University; the Animal Hospital at the Houston Zoo; the University of Texas Basketball Pavilion and Student Center; the University Life Center at the UT Health School of Dentistry; and the Denton A. Cooley, M.D. Hall at the Texas Medical Center Library.

Denton Arthur Cooley passed away at the age of ninety-six at his home in Houston on November 18, 2016. He was buried in Glenwood Cemetery.

Denton Arthur Cooley, 10,000 Hearts: A Surgeon’s Memoir (Austin: University of Texas Press, 2012). Denton A. Cooley, MD papers; MS 043; John P. McGovern Historical Center, Texas Medical Center Library. D. A. Cooley, R.D. Bloodwell, G. L. Hallman, and J. J. Nora, “Transplantation of the Human Heart: Report of Four Cases,” The Journal of the American Medical Association 205 (1968). Joseph S. Coselli, “Denton A. Cooley: In Memoriam,” Journal of Thoracic and Cardiovascular Surgery 153 (2017). “Honoring Denton A. Cooley,” AATS Foundation (, accessed July 29, 2020. November 18, 2016. Mimi Swartz, “The Rivalry Between Two Doctors to Implant the First Artificial Heart,” Smithsonian Magazine (April 2019) (, accessed July 29, 2020.

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Time Periods:
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The following, adapted from the Chicago Manual of Style, 15th edition, is the preferred citation for this entry.

Heather Green Wooten, “Cooley, Denton Arthur,” Handbook of Texas Online, accessed May 19, 2022,

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November 11, 2020
November 11, 2020

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