Clarence Dennis, 96; Physician Was Pioneer in Open-Heart Surgery

Dr. Clarence Dennis, who performed the first open-heart surgery that included the use of a heart-lung machine, which he helped develop, has died. He was 96.

Dennis died July 11 of dementia at Lyngblomsten Care Center in St. Paul, Minn., said his wife, Mary Dennis.

The idea of a machine that could keep blood flowing to prevent damage while a patient’s heart was stopped to make repairs “seemed very enchanting,” Clarence Dennis said last year.

In April 1951, the idea became reality when Dennis operated on a 6-year-old girl. She died within hours, but the heart-lung machine had done its job, Dr. C. Walton Lillehei, another pioneering surgeon who observed the operation at the University of Minnesota, once recalled.

A second operation two weeks after the first also was unsuccessful, because of a staff member’s mistake during surgery.

Dennis soon left the University of Minnesota for Downstate Medical Center of the State University of New York, where he was chairman of the surgery department from 1951 to 1972 and earned a reputation as a masterful surgeon and teacher.

“He was really a Renaissance person. The heart was at that time the Holy Grail -- no one thought anyone could operate on it,” said Dr. Michael Zenilman, now chairman of the Downstate surgery department. “Dr. Dennis and others had the nerve and audacity to go into that area.”

Dennis had begun researching the concept of a heart-lung machine in the late 1930s at the University of Minnesota, which was the birthplace of heart surgery and a hub of academic surgery in the 1940s and ‘50s, Zenilman said.

On June 30, 1955, Dennis became the second doctor in the country to perform successful open-heart surgery -- meaning the patient lived -- with the aid of a mechanical pump oxygenator, or heart-lung machine. He had built the device in a machine shop.

His friend and colleague, Dr. John H. Gibbon Jr., had achieved success first in 1953 in Philadelphia.

Last year, Dennis lamented that he felt obligated not to call attention to the teenage patient who became his first success. She “celebrated her emancipation from heart disease by immediately becoming illegitimately pregnant,” he said.

Dennis was born June 16, 1909, in St. Paul, where his father was a surgeon.

He graduated from Harvard University in 1931 and earned his medical degree from Johns Hopkins University four years later.

He later received a master’s in physiology and a doctorate in surgery from the University of Minnesota.

From 1972 to 1974, Dennis headed a National Heart and Lung Institute program in Bethesda, Md., that focused on developing artificial hearts.

Dennis invented and patented surgical instruments throughout his career, but his final patent, issued in 1999, was for a bread slicer, Zenilman said.

In addition to his second wife, whom he married in 1977, Dennis is survived by a daughter, three sons, a stepdaughter and a stepson. His first marriage ended in divorce.