World-renowned heart surgeon Dr. Michael DeBakey died of natural causes late Friday, according to the DeBakey Heart and Vascular Center at Methodist Hospital in Houston. He was 99.

In a career spanning more than 70 years ago, DeBakey performed more than 60,000 heart surgeries. His patients include late American presidents John F. Kennedy, Lyndon Johnson and Richard Nixon, the last Shah of Iran and King Hussein of Jordan.

Acknowledged as the father of modern cardiovascular surgery, the physician led the way in performing many groundbreaking surgeries, including the first removal of a carotid artery blockage in 1950; the first aorto-coronary bypass surgery (1964); the first use of a ventricular assist device to pump blood and support a diseased heart in 1966; and some of the first U.S. heart transplants (1968-69).

DeBakey pioneered in surgical procedures in bypassing blocked arteries in the neck, legs and heart and also made Houston a major center for heart surgery and research.

In 1969, he received the Presidential Medal of Freedom with Distinction, the highest honor that can be bestowed on a U.S. citizen and was also awarded the prestigious U.N. Lifetime Achievement Award in 1999. In April, DeBakey, was presented with the Congressional Gold Medal by President George Bush and members of Congress.