What was originally thought to be a minor heart ailment for former President George W. Bush turned out to be much more serious.

According to a National Journal report, the blocked artery found during a routine procedure in August turned out to be potentially life threatening. When a CT angiogram revealed a 95-percent blockage in one of his coronary arteries, Bush, 67, agreed to allow doctors to use a stent to open the blockage, the report stated.

"He was more than 95% occluded," a source told the National Journal. "With a blockage like that in a main artery you're supposed to die. He was pretty lucky they caught it."

In August, a routine stress test revealed changes in Bush's electrocardiogram readings. The CT angiogram was immediately ordered, revealing the blockage. On August 6, Bush underwent a procedure to insert a stent, which helps to open a narrow artery, as a proactive measure to help prevent heart attacks. There have been no reports of complications since.

Bush spokesman Freddy Ford originally said the former president didn't experience any symptoms before undergoing a routine stress test during his annual physical exam in Dallas.

The report comes as a surprise as Bush was one of the more active and physically fit presidents. He has remained active and hosted a 62-mile mountain bike race on his ranch in Crawford Texas over Memorial Day weekend.

"He's back on the bike – easy, not hard," a friend told the National Journal. "But he's feeling terrific and doing fine."