EMBED >More News Videos Denton Cooley's daughters share memories after his death.

HOUSTON (KTRK) -- Dr. Denton Cooley was a trailblazer on the cutting edge of heart medicine.The world-famous Houston heart surgeon discovered many techniques still used in cardiovascular surgery. In the late 1960s, Cooley performed the first successful human heart and artificial heart transplants in the United States.During his career, Cooley and his team at Texas Heart Institute performed more than 118,000 open heart operations. This is more than any other group in the world.While Cooley is no longer with us, his legacy endures through his life-saving work and in the memories of those who knew him best, including his family and one former president.Cooley died on November 18, 2016 at the age of 96.His family shared memories of a man who pioneered heart transplantation, developed an artificial heart and founded the Texas Heart Institute."He made sure he had time for each one of us, all of my children, all of their children, all of our grandchildren," Susan Cooley said.Longtime friend Joanne King Herring remembered his skill and precision."Ninety-nine percent of his patients were those that other doctors had given up on, and we said 'Denton, you can't do 18 operations a day and survive.' And he said, 'you tell me who I'm going to say no to,'" she said.Former President George H. W. Bush released this statement about Cooley when he died: