She said he had no procedures scheduled Thursday, but further tests would be done to make sure the stent was working correctly.
Walesa, 64, has been in Houston this week undergoing tests to determine whether he needs a heart transplant. Doctors said they plan to place a pacemaker in Walesa's chest on Friday.
"We're doing everything we can to make sure Mr. Walesa doesn't need a transplant right away," Dr. Guillermo Torre, a heart specialist at the medical center, said in the statement.
"We have high hopes that we will be able to restore function in his heart by other means, thereby relieving him of symptoms like chest pain, fatigue and shortness of breath."
Fairchild said the pacemaker is one of the things they will try to help Walesa avoid a transplant.
"It's designed to help resynchronize his heartbeat," Fairchild said. "The goal is to help his heart function improve."
Walesa, a former Gdansk shipyard electrician, led a workers' strike in 1980 that grew into the nationwide Solidarity freedom movement against Poland's communist authorities, earning him a Nobel Peace Prize in 1983.
In 1989, Solidarity toppled Poland's communist regime and Walesa went on to serve as Poland's first democratically elected president, from 1990-95.