Former President Clinton, who underwent major surgery to clear blocked arteries six years ago, suffered chest discomfort Thursday and was taken to a New York hospital, where doctors gave him an excellent prognosis after inserting stents in one of his coronary arteries.

Clinton’s cardiologist, Dr. Allan Schwartz, who oversaw the roughly hourlong procedure, said Clinton, 63, had been up and about and was expected to go home Friday. He could be back at work within days.

Schwartz emphasized that the procedure was not caused by dietary or lifestyle problems but was the result of a side effect seen in many patients who have undergone bypass surgeries.

He said that Clinton did not have a heart attack and that his heart did not suffer any damage.

“Just as illnesses have natural histories, treatments have natural histories,” said Schwartz, adding that there is “about a 10 to 20% failure rate at five to six years” after the type of operation Clinton underwent in 2004.

Schwartz also said Clinton’s symptoms should not be described as chest pains. Rather, he had experienced feelings of pressure and constriction in recent days. They were “brief in nature, but because they were repetitive, he contacted me,” Schwartz said during a news briefing outside New York-Presbyterian Hospital.

The doctor said Clinton was “in good spirits” after the procedure, which went “very smoothly.”

According to a White House official, President Obama “spoke to Clinton shortly before 7 p.m. and wished him a speedy recovery. . . . Clinton said he was feeling ‘absolutely great.’ ”

Secretary of State Hillary Rodham Clinton, who learned of her husband’s hospitalization while in Washington, arrived at the hospital about 7:30 p.m. The couple’s daughter, Chelsea, was also there, Schwartz said.

Aides to the secretary of State said she planned to take a previously scheduled trip to the Persian Gulf but would delay her departure from Friday until Saturday, according to the Associated Press.

The insertion of stents is considered a relatively common procedure. It was a reminder of the health risks still facing the former president, who doctors said in 2004 could have suffered a major heart attack had his heart problems not been diagnosed in time.

At that time, as in the latest incident, Clinton sought medical help after experiencing chest discomfort. “When it became repetitive,” Schwartz said, “he recognized that it might be a problem with his heart, and that’s when he consulted me and that’s when we acted.”

The quadruple bypass surgery, which was performed at the same hospital as Thursday’s less-invasive procedure, required doctors to surgically saw open Clinton’s chest and reroute blood flow around his heart’s blocked arteries. Doctors said his long-term recovery would depend on changing his diet to one with little salt and saturated fats.

Schwartz said Clinton had done that.

“He has really toed the line in terms of diet and exercise,” he said. “His prognosis is excellent.”

Since leaving the White House, Clinton has taken on an exhausting work and travel schedule.

He has made two trips to Haiti as a United Nations special envoy in response to the Jan. 12 earthquake, which killed an estimated 200,000 people.

He also traveled to Davos, Switzerland, in the last month to attend the World Economic Forum.

Clinton was being treated at the Vivian and Seymour Milstein Family Heart Center of Presbyterian Hospital; he attended the groundbreaking of the facility in the Washington Heights neighborhood of Manhattan in 2006.

“He’d hoped to come back as a visitor and not as a patient, but nevertheless he is in great spirits,” said Steven Barnes, director of communications at the Clinton Foundation.

At least 1.25 million Americans a year undergo the stent procedure that was performed on Clinton, and the outcomes are generally good.

A balloon on the end of a catheter is inflated at the site of the blockage to compact the plaque against the artery walls, a procedure known as angioplasty.

Then, using the same catheter, surgeons leave behind a stent -- a small, spring-shaped piece of wire that keeps the plaque from expanding again.

When the procedure was first used, the wires were bare and the rate of reclosure of the artery was relatively high.

More recently, surgeons have favored so-called drug-eluting stents that slowly release medicines that help to prevent reclogging.

tina.susman@latimes.com

geraldine.baum

@latimes.com

thomas.maugh

@latimes.com

Times staff writer Robin Abcarian in Los Angeles contributed to this report.