I don't know where you are from. In the UK, fitness is related to your ability to work and if you can only walk a few paces, you are medically classes as unfit for work. Who would want to hire someone who is just waiting for a heart attack?
As Kenkeith states, after treatment many people recover with no limitations but some don't. If tissue death has occured then full recovery may never occur. If the arteries are too diseased, even a bypass may not be sufficient to provide anything more than slight benefits. Every case is an individual case and has to be assessed independantly.
If the doctors can stent the area where it is closed off then it could be the same day and then you are out. If it would lead to open heart, most stay for a week or less and recoup at home. Medical leave would be determined by the doctor, but most likely no.
Coronary Artery Disease (CAD) is a condition that begins to occlude the coronary vessels with plaque. Ischemia (lack of blood flow) is usually due to occlusions, and the dx indicates there is occlusion at the location indicated.
If the occlusion is very serious, the symptoms may prevent you from doing your job. The symptoms would/could be shortness of breath, chest pain, etc. With successful treatment, you should be able to do your job. Medication can relieve you of any symptoms and no job restrictions...your treating doctor will inform you of any limitations.