HOUSTON—A half century ago, as Dr. Michael E. DeBakey pushed forward with his groundbreaking research and maverick approach to medicine, heart surgery was a medical marvel.

Today, in part from DeBakey’s contributions, it routinely saves the lives of thousands of people each day.

The world-famous cardiovascular surgeon, who pioneered such now-common procedures as bypass surgery and invented a host of devices to help heart patients, died Friday night in Houston at the age of 99.

DeBakey died from “natural causes” shortly after arriving at the hospital, according to a statement issued early Saturday by Baylor College of Medicine and Methodist Hospital. He died at The Methodist Hospital, whose heart and vascular center bears his name.

DeBakey, whose career spanned more than 70 years, counted world leaders among his patients and helped turn Baylor from a provincial school into one of the nation’s great medical institutions.

“Dr. DeBakey’s reputation brought many people into this institution, and he treated them all: heads of state, entertainers, businessmen and presidents, as well as people with no titles and no means,” said Ron Girotto, president of The Methodist Hospital System.

Girotto said the surgeon “has improved the human condition and touched the lives of generations to come.”

A tireless worker and stern taskmaster, DeBakey literally had scores of patients under his care at any one time. He performed more than 60,000 heart surgeries during his career.

“There is no question that he was one of the pioneers of cardiovascular surgery in the last half of the 20th century,” said Dr. Denton Cooley, president and surgeon-in-chief at the Texas Heart Institute in Houston and a longtime DeBakey rival.

Cooley said one of DeBakey’s greatest legacies is “he influenced so many students to pursue careers in cardiovascular surgery.”

As recently as April, DeBakey traveled to Washington to add the Congressional Gold Medal to his long list of honors. At the ceremony, President Bush said the award—Congress’ highest civilian honor—put DeBakey in the company of inventor Thomas Edison, Army doctor Walter Reed and Jonas Salk, who developed the polio vaccine.

While still in medical school in 1932, DeBakey invented the roller pump, which became the major component of the heart-lung machine, beginning the era of open-heart surgery. The machine takes over the function of the heart and lungs during surgery.

It was the start of a lifetime of innovation. The surgical procedures DeBakey developed once were the wonders of the medical world. Today, they are commonplace procedures in most hospitals.