1. Know the Risk Groups
Aortic stenosis (AS) is a very common heart valve disorder. The condition is present in almost 5 percent of adults over the age of 75. AS is the narrowing of the valve leading out of the heart. The most common reason is calcification of the valve that has developed over years. In patients under 60 years of age, the most common reason for aortic stenosis to develop is a congenital abnormality of the valve, called bicuspid aortic valve. In this case, there are three leaflets instead of two. This abnormality results in the accelerated calcification of the valve, which causes its leaflets to fuse together and restrict blood flow out of the heart.
2. Watch for Early Symptoms
Patients with AS are often free of symptoms until the valve becomes severely narrowed. The area for blood flow in a normal aortic valve is approximately 4 cm2. In AS with symptoms, the opening is often less than 1 cm2. Patients with AS often feel fatigued or short of breath. Chest pain is a serious symptom that implies the valve is so narrow that it is affecting blood flow to the heart muscle. When patients are severely affected by AS, they may experience blackouts as the blood flow out the heart is insufficient to reach the brain. In end-stage patients with AS, the heart muscle has been affected and congestive heart failure (CHF) develops. Patients are often short of breath at rest and unable to lay flat because of swollen legs. It is important to treat AS when symptoms of chest pain or blackouts are present, because when CHF is present, it may be too late.
3. Diagnose Aortic Stenosis
AS is diagnosed by hearing a loud murmur on exam, which radiates to the neck. There is also a decrease in the strength of the pulse as it is felt in the neck. An echocardiogram is the most efficient way to determine the severity of the AS. This test is done in the office and will directly measure the opening of the valve and evaluate the function of the heart. If the test shows AS, and symptoms are present, many cardiologists will elect to perform a heart cath. This procedure is the gold standard for the evaluation of the aortic valve and measures pressures in the heart chambers and can show if the arteries are blocked as well. Some patients will need a valve replacement and coronary artery bypass at the same time.
4. Consider Treatment Implications
The treatment of AS depends on the severity of symptoms and the findings of the various diagnostic studies. Replacement of the valve by cardiac surgery is the best way to treat AS when symptoms are present. The procedure is done by a cardiothoracic surgeon and requires a heart lung machine (cardiopulmonary bypass) to circulate the blood while the heart is in standstill for the removal of the old valve and the insertion a replacement. The type of valve used is metallic in younger patients. This type will last many years and will likely not require repeat surgery in the future, but does require lifelong treatment with coumadin, a very strong blood thinner. In older patients a biologic valve made from cow or pig tissue can be used and will last about 10 years. This type of valve only requires aspirin. The choice of valve type is a serious discussion that the surgeon must have with every patient with AS.
5. Investigate Emerging Treatments
New therapies for AS are currently under evaluation. In certain patients with high surgical risk, a balloon can be inflated across the valve to temporarily decrease symptoms. This procedure, known as valvuloplasty, unfortunately is not a great long-term option. Recently, replacement of the aortic valve has been done via the leg, using a valve mounted on a balloon. This percutaneous aortic valve replacement procedure is being widely studied at some of the world's top cardiac centers. In high-risk patients this may be a future option that might be as good as surgery without the dangers of an open heart procedure.
