Aortic stenosis is a narrowing of the aortic valve, which is the valve between the heart and the aorta-the main blood vessel of the body. Symptoms of aortic stenosis include shortness of breath, leg swelling, chest pain, and syncope- or passing out, fainting. An echocardiogram or ultrasound of the heart confirms the diagnosis. Surgery is the traditional treatment for severe aortic stenosis, but valves done through catheters are being tested.