Back in 2004, Bill Clinton underwent quadruple bypass surgery. In 2005, doctors removed scar tissue and fluid that had built up after that surgery.
"After five to ten years of bypass surgery there is a high incidence of grafts closing," said cardiologist Dr. Daniel Eisenberg, from Providence St. Joseph Medical Center.
Now, doctors say Clinton has had two stents placed in a coronary artery.
"A stent is a device that we put into the artery that looks like the inside of the pen, like the spring," said Dr. Eisenberg. "We put that spring inside the artery and we use a balloon inside of that to smash it against the walls of the artery so it keeps the artery open."
Without knowing the specifics of Clinton's medical history, it's hard to say exactly what doctors had to deal with, but there are two likely scenarios, according to Dr. Eisenberg.
"He's having a problem with his heart due to blockage of an artery, or a graft to an artery," said Dr. Eisenberg. "The stent is there to open up the artery and get the flow back to the area."
So what can someone with Clinton's heart disease profile continue expect long term?
Dr. Eisenberg says the same lifestyle and risk factors that were probably there before don't go away.
"The traditional risk factors people have are high blood pressure, high cholesterol, overweight still follows you after a stent and still increases your risk of having blockage recur," said Dr. Eisenberg.
A representative for Bill Clinton says the former president is in good spirits Thursday. He adds that Clinton will continue to focus on the work of his foundation and long term recovery efforts.