NEW YORK (AP) -- Former President Bill Clinton, who had quadruple bypass surgery more than five years ago, was hospitalized Thursday to have a clogged heart artery opened after suffering discomfort in his chest.
Two stents resembling tiny mesh scaffolds were placed inside the artery as part of a medical procedure that is common for people with severe heart disease.
The 63-year-old Clinton was "in good spirits and will continue to focus on the work of his foundation and Haiti's relief and long-term recovery efforts," said an adviser, Douglas Band.
Terry McAuliffe, former Democratic National Committee chairman and a close friend of the Clintons, said Clinton participated in a conference call on earthquake relief as he was being wheeled into an operating room.
He expected Clinton to be released from the hospital Friday.
Secretary of State Hillary Rodham Clinton traveled from Washington to New York to be with her husband, who underwent the procedure at New York Presbyterian Hospital, the same place where his bypass surgery was done in September 2004.
At that time, four of his arteries were blocked, some almost completely, and he was in danger of an imminent heart attack.
Cardiologist Allan Schwartz said the former president had been feeling discomfort in his chest for several days, and tests showed that one of the bypasses from the surgery was completely blocked.
Instead of trying to open the blocked bypass, doctors reopened one of his original blocked arteries and inserted the two stents. The procedure took about an hour, and Clinton was able to get up two hours later, Schwartz said.
There was no sign the former president had suffered a heart attack, and the new blockage was not a result of his diet, Schwartz said.
The doctor said Clinton could return to work Monday.
"The procedure went very smoothly," Schwartz said, describing Clinton's prognosis as excellent.
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 need for another artery-opening procedure will not affect Clinton's long-term prognosis, said Dr. William O'Neill, a cardiologist and executive dean of clinical affairs at the University of Miami's Miller School of Medicine.
"It doesn't really affect long-term survival. It's a quality-of-life thing. He'll have to have careful monitoring, regular stress tests."
O'Neill said he had done 10 or 15 such procedures in a single patient over a period of time, and they still live long lives.
Former Senate Republican leader Bill Frist of Tennessee, a heart surgeon, said on his Twitter page that Clinton was "doing well."
"Thousands of these done every week. He will be fine. He will be active again very, very soon," Frist said.
Nearly 1 in 5 patients who have angioplasties have previously had a bypass operation, according to a patient registry maintained by the American College of Cardiology.
Doctors will have to watch Clinton closely for signs of excessive bleeding from the spot in the leg where doctors inserted a catheter, said Dr. Spencer King, a cardiologist at St. Joseph's Heart and Vascular Institute in Atlanta and past president of the cardiology college.
Complications are rare. The death rate from non-emergency angioplasty is well under 1 percent, King said.
After seeing his cardiologist, Clinton's Secret Service motorcade took him to the hospital, where he walked in on his own.
A White House official said the former president's condition did not come up during a meeting Thursday between President Barack Obama and the secretary of state. The afternoon meeting took place a few hours before word of Clinton's heart procedure became public.
The official spoke on condition of anonymity because details of the meeting were considered private.
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. She left the hospital at about 11:30 p.m. without speaking to reporters.
Clinton's daughter, Chelsea, was also with him at the hospital.
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 legend as an unhealthy eater was sealed in 1992, when the newly minted presidential candidate took reporters on jogs to McDonald's. He liked hamburgers, steaks, french fries - lots of them - and was a voracious eater who could gobble an apple (core and all) in two bites and ask for more.
Two of his favorite Arkansas restaurants were known for their large portions - a hamburger the size of a hubcap and steaks as thick as fists.
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.
Other than his heart ailments, Clinton has suffered only typical problems that come with aging.
In 1996, he had a precancerous lesion removed from his nose, and a year before a benign cyst was taken off his chest. Shortly after leaving office, he had a cancerous growth removed from his back. In 1997, he was fitted with hearing aids.
AP Medical Writer Marilynn Marchione reported from Milwaukee. Beth Fouhy and Cristian Salazar in New York, and Julie Pace, Matthew Lee and Darlene Superville in Washington also contributed to this report.