(CNN) - Former first lady Barbara Bush was released from a Texas
hospital Wednesday, four days after being admitted for a series of tests.
Doctors believe the 84-year-old wife of former President George H.W. Bush may have suffered a mild relapse of Graves disease, a thyroid condition for which she was first treated in 1989, according to a statement released from Houston's Methodist Hospital.
In response, Mrs. Bush's medication levels have been adjusted, the statement said. "Upon discharge she was alert, talkative and appeared to be getting stronger as she prepared to return home," it said.
Last year, Mrs. Bush underwent open-heart surgery, during which doctors replaced her aortic valve with a biologic valve. She spent nine days in the hospital afterward.
Doctors believe the valve "is working very well," the hospital's statement said.
In November 2008, Mrs. Bush underwent surgery for a perforated ulcer.
- CNN's Dick Uliano contributed to this report