Aortic valve regurgitation diagnosed. What is prognosis?

Depends on severity. Mild aortic valve insufficiency can be asymptomatic and watched for years. Severe aortic regurgitation may be a life threatening emergency. Careful follow up and heeding the recommendation of your physician are important.
Depends. Mild aortic regurgitation with an otherwise normal heart can remain unchanged for many many years. More severe aortic regurgitation with enlargement or weakening of the heart may require prompt surgery. The range of prognoses is quite large depending on the characteristics of the patient.