NEW YORK - Former President Clinton checked into a New York City hospital early Thursday to undergo more surgery on his chest.
Clinton, 58, arrived at New York-Presbyterian Hospital/Columbia University Medical Center shortly after 5 a.m. for a low-risk operation to remove fluid and scar tissue that developed in his left lung after his quadruple heart bypass six months ago.
The Secret Service, police and hospital security staff conducted a sweep of the walkways and corridors of the hospital pavilion as Clinton was whisked inside through a side entrance.
Doctors were expected to perform the new procedure sometime in the morning. It is done through a small incision or with a video-assisted thoracoscope inserted between the ribs.
On Wednesday, Clinton was in Florida at a charity golf tournament to benefit tsunami victims. He appeared relaxed, joking about his game and saying he wasn't worried.
"I've had an unusual life. If something happens - if I get struck by lightning on the golf course today - I'd wind up ahead of where 99.99 percent of the people who ever lived did," he said. "I'm just grateful for every day when the sun comes up. But it is not a dangerous procedure, unless something totally unpredictable happens."
The scar tissue, which developed because of fluid buildup and inflammation, has caused compression and collapse of the lower lobe of Clinton's left lung, his office said in a statement earlier this week.
The condition "has caused the president some discomfort in recent weeks, but he has otherwise been in very good condition, recently passed a stress test and is walking up to 4 miles a day," the statement said.
The problem occurs in a fraction of 1 percent of cases, said Dr. Craig Smith, who performed Clinton's bypass surgery in September.
Clinton's wife, Sen. Hillary Rodham Clinton, said she would be in New York for the surgery and was "very confident about the outcome."
More than 1,000 people have sent the 42nd president good wishes through his Web site.
"We still need your strong and capable leadership in the nation and the world!" said a message from K. and B. Fletcher. "We both wish you a speedy and uneventful recovery!"
Clinton was discharged from the hospital four days after his September surgery. Since then he has presided over the opening of his presidential library in Little Rock, Ark., and joined former President George H.W. Bush for a public relations campaign to help raise money for the Asian tsunami victims.
Across the street from the hospital, good wishes and prayers for Clinton were offered at a restaurant named El Presidente. "I pray to God that he is well, that he comes out healthy," said manager Wilton Rafael Marte Fermin, 41, a native of the Dominican Republic.