Washington - Former first lady Barbara Bush underwent surgery Wednesday to replace a heart valve, a family spokesman said late Wednesday.

The open-heart surgery was performed at The Methodist Hospital in Houston on the 83-year-old wife of former president George Bush and mother of George W Bush, who completed eight years as president in January.

"The surgery went extremely well," Dr Gerald Lawrie, the heart surgeon who performed the valve replacement, was quoted as saying by the Houston Chronicle on its website. I expect her to recover fully and soon resume her normal activities."

In a statement, the elder president Bush said: "We have every confidence she is in the best hands."

The patient was alert and speaking with her husband Wednesday evening following the surgery. She is expected to remain hospitalized for at least a week.

Bush is fully recovered from an unrelated stomach ulcer, for which she was hospitalized late last year.