The 63-year-old should be discharged from hospital in the next few days following his admission last Wednesday due to chest pains.
It was confirmed that the cause of Houllier's pain was a dissection of the descending aorta, which occurs when a tear in the inner wall of the aorta causes blood to flow between the layers of the wall of the aorta and force the layers apart.
While in hospital the former Liverpool manager received a plethora of messages wishing him well and he was quick to stress his gratitude.
"I am extremely touched by all the messages I have received and by the reaction of people throughout the world of football. It has been overwhelming actually," he said in an official club statement.
"I'm especially grateful to the Villa fans for their genuine concern and encouragement and to the fans of clubs up and down the country. There has been a groundswell of goodwill and I appreciate this so much."
Source: PA
Source: PA