NEW ORLEANS (AP) — John Lockwood Ochsner — a world-renowned cardiac surgeon — died Friday at age 91, Ochsner Health Systems in New Orleans announced.

Ochsner was considered a pioneer in valve and coronary surgery, the use of pacemakers and early heart, lung and liver transplants. He performed Louisiana’s first heart transplant in 1970.

He had retired from surgery in 2004, at age 77, but continued to see patients.

He was the son of Alton Ochsner, who, in 1942, was one of the founders of what is now Ochsner Health Systems.

“For more than 57 years, Dr. Ochsner has been a consistent, larger-than-life presence across our hospitals and with our staff and patients,” the institution’s board chairman, Andy Wisdom, and CEO, Warner Thomas, said in a statement issued Friday. “His sphere of influence spanned across New Orleans, generations of Ochsner physicians and colleagues and the international medical community.”

Ochsner received his medical degree from Tulane University in New Orleans. He completed surgical residencies and served as Chief Surgical resident at Baylor University Affiliated Hospitals and Texas Children’s Hospital.

He returned to join the Ochsner staff in 1961.

Funeral arrangements have not been released.

Survivors include his wife of 64 years, Mary Lou Ochsner, and four children.