Former US President Bill Clinton has undergone a heart procedure in New York City after complaining of discomfort¹ in his chest, a spokesman has said.

因胸部略感不适，美国前总统比尔·克林顿在纽约接受了一次心脏手术。

Bill Clinton served two terms as US president, from 1993 to 2001

The 63-year-old had two stents（支架） - wire-mesh（网眼，网丝） tubes that help the flow of blood - placed in a coronary artery²（冠状动脉） at Columbia Presbyterian hospital.

His counsellor（顾问） , Douglas Band, said in a statement that he was in good spirits.

Mr Clinton had quadruple（四倍的，四重的） -bypass surgery（心脏搭桥手术） in September 2004 after experiencing chest pains and shortness of breath.

His wife, US Secretary of State Hillary Clinton, headed to New York from Washington to be with him.

The state department said she would still be travelling to Qatar and then Saudi Arabia on the weekend as planned, although her flight will leave later to allow her to spend more time in New York.

Their daughter, Chelsea, is already with Mr Clinton at the hospital.

Mr Band said: "Today President Bill Clinton was admitted to the Columbia Campus of New York Presbyterian Hospital after feeling discomfort in his chest.

"Following a visit to his cardiologist（心脏病学家） , he underwent（经历，遭受） a procedure to place two stents in one of his coronary arteries³. President Clinton is in good spirits."

Mr Clinton served two terms as president, during which he became known for his love of fast food and jogging（慢跑） .

He later set up the William J Clinton Foundation to promote and address international humanitarian⁴ causes such as treatment and prevention of HIV/Aids and global warming.

Last year, he was appointed UN special envoy⁵ to Haiti, and has been working in recent weeks to help the relief effort（救灾工作） in the wake of（紧紧跟随，作为……的结果） the devastating⁶（毁灭性的） earthquake there on 12 January.

Mr Band said that after recovering, the former president would "continue to focus on the work of his foundation and Haiti's relief and long-term recovery efforts".

A friend of Mr Clinton's told ABC News that he had been suffering from a cold and had been worn out（疲惫，精疲力竭） from a trip to Haiti last week.

Stents are tiny wire-mesh tubes used to keep an artery open after it is unclogged in an angioplasty（血管成形术） procedure.

Doctors thread a tube through a blood vessel⁸ in the groin（交叉拱，腹股沟） to a blocked artery, inflate⁹（膨胀，充气） a balloon to flatten¹⁰ the clog⁷, and slide the stent into place.

Dr Clyde Yancy, the president of the American Heart Association, said it was "not unexpected" that Mr Clinton needed two new stents.

Patients often required another procedure five to 10 years after a bypass（旁路，支路） or angioplasty because new clogs¹¹ tended to develop, he said.

"This kind of disease is progressive. It's not a one-time event, so it really points out the need for constant surveillance（监督，监视） ," Dr Yancy told the Associated Press.