Suggest Treatment For Recurring Edema In Ankles

My 84 year old mother has atrial fib. She was in the hospital and developed severe edema in her legs, turning her legs purple. Pedal pulses were difficult to find and she was put on IV lasix for the edema. She was moved to Hospice care and the edema left, color returned to normal and pedal pulses felt. She seemed to be improving in many ways, but today I saw some edema returning to her ankles. What can be done?