Heart surgeon Michael DeBakey, whose revolutionary heart transplants and coronary bypass surgical procedures made him one of the most important doctors of 20th century medicine, has died at the age of 99.

According to a statement released on Saturday morning by the Baylor College of Medicine and Methodist Hospital, Michael DeBakey died of natural causes soon after being transported at the hospital whose heart and vascular center bears his name.

In a career that extended over seventy years, the brilliant heart surgeon reinvented a large number of operations and surgical methods that nowadays are regular in the treatment of heart disorders and led many to regard him as the father of modern cardiovascular surgery.

His most famous contribution to medicine was the now-usual coronary bypass operation for clogged arteries, which he first performed in 1964, employing leg veins in order to bypass obstructed or harmed areas between the aorta and the coronary arteries.

An indefatigable professional and uncompromising taskmaster, Michael DeBakey carried out more than 60,000 heart surgeries throughout his career and treated very significant figures of history such as presidents Kennedy, Johnson and Nixon, former Russian President Boris Yeltsin, the Shah of Iran, King Hussein of Jordan, Turkish President Turgut Ozal and Nicaraguan leader Violetta Chamorro.

Michael DeBakey, the Louisiana-born son of Lebanese immigrants, developed his interest towards medicine while assisting the conversations physicians were having at his father’s pharmacy. He was still a student at Tulane University in New Orleans in 1932 when he invented the roller pump, which is a decisive element of the heart-lung machine that facilitated the progress of open-heart surgery.

In the late 1990s, the surgeon participated directly in founding the Michael E. DeBakey Heart Institute at Hays Medical Center in Hays, Kan.

Michael DeBakey's first wife, Diana Cooper DeBakey, died of a heart attack in 1972. He is survived by his second spouse, Katrin Fehlhaber, their daughter, and two of his four sons from his first marriage.