A stenosis of the heart, normally called an aortic stenosis, occurs when the aortic valve narrows, slowing blood flow from the heart to the rest of the body.
The aortic valve is one of the heart’s four valves; their function is to control the direction of blood flow through the heart’s four chambers. The valves open to let blood into a chamber and close to prevent blood from flowing backward. The aortic valve controls blood flow from the left ventricle to the aorta. Stenosis occurs when the valve does not open wide enough to allow maximum blood flow to the aorta. As a result, the heart has to work harder to pump blood through the narrowed valve opening. Eventually, the heart muscle thickens and requires an extra amount of blood to continue pumping. Sometimes, and especially during physical activity, the blood supply does not meet the needs of the heart, causing chest pain, fainting and even heart failure.
Symptoms of aortic stenosis include chest pain, dizziness, lightheadedness, fatigue (especially during increased activity), shortness of breath and heart palpitations. Stenosis can eventually cause heart failure, symptoms of which include shortness of breath, fatigue, and swollen ankles and feet. Symptoms may not present right away; often, the first sign of stenosis is a heart murmur that is discovered by a doctor during a routine physical exam. A heart murmur often shows up long before any outward signs of aortic stenosis.
Aortic stenosis is mainly a disease seen in older people. As people age, calcium deposits from blood accumulate on the aortic heart valve. In some people, this causes stiffening of the cuspids (three small flaps of tissue that make up the valve) of the valve, which leads to stenosis of the valve. This cause is most common in people over 60. Another common cause of aortic stenosis is rheumatic fever. Rheumatic fever is a complication of strep throat and may result in scar tissue forming on the valve. Thick scar tissue narrows available space and can also create a good surface for calcium deposits. This cause is often seen in adults who had rheumatic fever as children. The other major cause of aortic stenosis is a congenital defect. Some babies are born with a narrowed aortic valve, and some are born with only two cuspids instead of the normal three—these babies have what is called a bicuspid valve.
Diagnosing aortic stenosis starts with a routine physical exam when your doctor uses a stethoscope to listen to your heartbeat for abnormal sounds like a heart murmur. If your doctor does hear a heart murmur, you may need to undergo several other tests to confirm an aortic stenosis diagnosis and to determine the severity of the illness. Other tests include a chest X-ray to check the size of the heart and to check for calcium deposits; an electrocardiogram, which measures your heart’s electrical impulses; an echocardiogram, which uses sound waves to produce images of the heart; various exercise tests to check the heart’s response to physical exertion; and imaging scans, such as magnetic resonance imaging (MRI) and computed tomography (CT) scans that provide detailed, three-dimensional images of the heart.
Medication may help ease symptoms of aortic stenosis, but the only way to cure it is to have surgery to repair or replace the aortic valve. Patients with mild or moderate symptoms may not need surgery right away and can be carefully monitored until, or if, symptoms become severe. The most common surgical procedure includes replacing the narrowed aortic valve with an artificial valve or a tissue valve from a cow, pig or human cadaver. Another surgical procedure involves inserting a catheter tipped with a balloon into the aortic valve. Once inside, the balloon is inflated—this opens up and stretches the valve, curing the stenosis and relieving the symptoms. However, this method, called balloon valvuloplasty, is not used often anymore as the valve tends to narrow again after the surgery when the balloon is removed. This procedure is only used on elderly patients who are too frail for surgery.