Doctors have reportedly performed surgery on former Poison frontman and TV reality star Bret Michaels to close a hole in his heart. The hole was discovered in April when Michaels was being treated for a brain hemorrhage. Soctors will insert a closure device into his heart, which will remain in his body permanently to stop abnormal blood flow between the two chambers of the heart. Without the procedure, the singer faces the risk of developing blood clots and an additional stroke.