Houston icon Dr. Michael DeBakey has died at the age of 99.

Dr. Michael Ellis DeBakey, internationally acclaimed as the father of modern cardiovascular surgery -- and considered by many to be the greatest surgeon ever -- died Friday night at The Methodist Hospital in Houston. He was 99.

Methodist officials said DeBakey died of natural causes. Dr. Marc Boom, executive vice president of Methodist, said DeBakey was taken to the hospital on Friday night after the surgeon's wife called 911. He was prounounced dead shortly after arriving.

Medical statesman, chancellor emeritus of Baylor College of Medicine, and a surgeon at The Methodist Hospital since 1949, DeBakey trained thousands of surgeons over several generations, achieving legendary status decades before his death. During his career, he estimated he had performed more than 60,000 operations. His patients included the famous -- Russian President Boris Yeltsin and movie actress Marlene Dietrich among them -- and the uncelebrated.

"He was a great contributor to medicine and surgery, of course," said Dr. Denton Cooley, president and surgeon-in-chief at the Texas Heart Institute in Houston and a longtime DeBakey rival.

"But he left a real legacy in the Texas Medical Center and at Baylor College of Medicine, where he's brought so much attention. Together we were able to establish Houston as a world leader in cardiovascular medicine.''

Cooley had known DeBakey since 1945. "In the first half of the 20th century, very little went on in this field," he said of cardiovascular surgery. "So when he and I began our careers, we pretty much had an open field."

"Dr. DeBakey singlehandedly raised the standard of medical care, teaching and research around the world," said Dr. George Noon, a cardiovascular surgeon and longtime partner of DeBakey's. "He was the greatest surgeon of the 20th century, and physicians everywhere are indebted to him for his contributions to medicine."