The principal problem with aortic stenosis is obstruction of blood flow. This usually does not occur to a significant degree in cases of AS due to idiopathic sclerosis.

People with rheumatic heart disease, or bicuspid valve, can develop symptoms of AS (most commonly) between the ages of 40 and 60. With an increase of obstruction to blood flow (through the stenotic valve), the heart attempts to compensate by enlarging. Eventually, the heart begins to decompensate and the patient will develop symptoms consistent with aortic stenosis.