My mom was diagnosed with aortic valve stenosis by echocardiogram. does she need surgery?

Depends: On how severe it is and the overall heart function. Frequentlyit is followed by echocardiograms unless symptoms of chest pain, heart failure or syncope occur. If these occur surgery is usually the best treatment option.

Depends how severe: Aortic stenosis is usually offered for patients with severe stenosis or moderate stenosis and symptoms. Once you reach either of these two levels of disease the chances of survival without surgical replacement is poor.