Aides to Mrs. Clinton said she still planned to go ahead with a previously scheduled trip to the Persian Gulf. The trip was to begin Friday afternoon, but now she is planning to leave Saturday so that she does not have to rush back to Washington.

Clinton's daughter, Chelsea, was also with him at the hospital.

In an angioplasty, the procedure Clinton had on Thursday, doctors thread a tube through a blood vessel in the groin to a blocked artery and inflate a balloon to flatten the clog. Often, one or more stents are used to prop the artery open.

The angioplasty is usually done with the patient awake but sedated. It's one of the most common medical procedures done worldwide. More than a million angioplasties are done in the United States each year, most involving stents.

"It's not unexpected" for Clinton to need another procedure years after his bypass, said Dr. Clyde Yancy, cardiologist at Baylor University Medical Center in Dallas and president of the American Heart Association.

The sections of blood vessels used to create detours around the original blockages tend to develop clogs five to 10 years after a bypass, Yancy explained. New blockages also can develop in new areas.

"This kind of disease is progressive. It's not a one-time event so it really points out the need for constant surveillance" and treating risk factors such as high cholesterol and high blood pressure, he said.

The former president has been working in recent weeks to help relief efforts in Haiti. Since leaving office, he has maintained a busy schedule working on humanitarian projects through his foundation.

Clinton's reputation as an unhealthy eater was sealed in 1992, when the newly minted presidential candidate took reporters on jogs to McDonald's. He was famously spoofed on "Saturday Night Live" as a gluttonous McDonald's customer.

Friends and family say Clinton changed his eating habits for the better after his bypass surgery.

"He has a brutal schedule. ... He travels more than 200 days a year, working on his global initiative, helping people," McAuliffe told CBS. "I hear people say, 'Will he slow down?' That's not President Clinton. If anything, he'll redouble his efforts if there's actually time to redouble what he does."

But should Clinton slow down a little?

"Yeah, probably," McAuliffe said. "But he's been doing this for 63 years and you're not going to change him. He always says, 'It's not about me; it's about all those people.'"

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AP Medical Writer Marilynn Marchione reported from Milwaukee; AP video journalist Ted Shaffrey in Chappaqua; Beth Fouhy, Marcus Franklin and Cristian Salazar in New York, and Julie Pace, Matthew Lee and Darlene Superville in Washington also contributed to this report.