(CNN) - Former President George W. Bush's heart situation that caused him to undergo a procedure in August was more serious than originally thought, as two sources close to the 43rd president now confirm he had a 95% blockage in an artery.
Bush, 67, had a stent placed in his heart in August at a Dallas hospital one day after the blockage was discovered.
While a 95% blockage is significant, Bush's doctors are not commenting about how grave the situation may or may not have been.
National Journal first reported the level of the blockage, but one source close to Bush downplayed any reports of a near-death experience. Another source said "it was very serious."
The rate at which a vessel becomes blocked is more important than the overall blockage, and the heart can do a good job of compensating, if it has time.
"Certainly President Bush was at significant risk having a 95% blockage in one of his coronary arteries. That doesn't mean he was going to have a heart attack," Warren Levy, a cardiologist, told CNN. "But certainly he was at significant risk for a heart attack and something did need to be done."
Marc Siegel, a physician and medical director of Doctor Radio at NYU Langone Medical Center, penned a column for USA Today in August praising the doctors' fast work on Bush's heart.
"Bush's stress test showed EKG changes, and what happened next was also prudent. A CT angiogram revealed a severe blockage in a crucial position in a coronary artery that was easily life threatening," he wrote.
Bush said last month at a golf tournament for other wounded veterans that he's "doing fine."
"Other than the fact that I nearly bled to death when I nicked myself shaving because I'm taking blood thinner, I'm doing pretty good," he joked in an interview with ABC's "Good Morning America." "I thought you were going to have to put a tourniquet on me."
Over Memorial Day weekend, Bush led another group of wounded warriors on an annual long distance bike ride at his ranch in Crawford, Texas.
The 43rd president was known for having good health during his tenure at the White House. For exercise, he was an active runner and frequently rode his mountain bike.
– CNN's John King, Erin McPike, Andrew Morse, and Ashley Killough contributed to this report.