Ambulatory means there is no emergency and refers to where the patient is and not to the disease itself (here the patient is out of hospital): for example there is no need to perform urgent PTCA or other procedures related to unstable CAD (coronary artery disease).
Another option is - to hospitalize the patient to perform urgent or planned procedures if the patient is unstable and there is deterioration in his/her status which may worsen and threaten the life.
The key word in this sentence " **stable** ".