Heart valves regulate the flow of blood through the heart's four chambers—two small, round upper chambers (atria) and two larger, cone-shaped lower chambers (ventricles). Each ventricle has a one-way "in" (inlet) valve and a one-way "out" (outlet) valve. Each valve consists of flaps (cusps or leaflets) that open and close like one-way swinging doors.
In the right ventricle, the inlet valve is the tricuspid valve, which opens from the right atrium, and the outlet valve is the pulmonary (pulmonic) valve, which opens into the pulmonary artery.
In the left ventricle, the inlet valve is the mitral valve, which opens from the left atrium, and the outlet valve is the aortic valve, which opens into the aorta.
As people age, the mitral and aortic valves thicken. The aorta becomes stiffer, which increases blood pressure and stress on the aortic valve, and the heart requires additional oxygen to pump blood effectively. These age-related changes may lead to symptoms and complications in older people with heart disease.
The heart valves can malfunction by
Either problem can greatly interfere with the heart's ability to pump blood. Sometimes a valve has both problems. Faulty valves generally create murmurs and other abnormal heart sounds that a doctor can hear with a stethoscope. Faulty valves can be identified by using echocardiography. Often, minor degrees of regurgitation are not detected with a stethoscope but are detected during echocardiography. Doctors often regard this as a normal finding.
Most faulty valves are not severely abnormal, and they do not affect the person in any way. Symptoms may include leg swelling, shortness of breath, palpitations, fatigue, chest pain, and fainting. Doctors often do periodic check-ups because a few faulty valves worsen over time to the point where intervention (repair or replacement) is required to decrease symptoms or prolong survival. Symptoms are not a reliable guide to the existence and severity of valve problems, so echocardiography (ultrasonography of the heart) is used to detect problems early. Sometimes doctors use exercise testing to help monitor people with certain heart valve disorders. In general, neither lifestyle measures nor drug treatment can slow the deterioration of an abnormal valve.
Understanding Stenosis and Regurgitation
A faulty valve may be repaired or replaced. Repair may require surgery but now may sometimes be accomplished during heart catheterization, particularly when the problem is a valve with stenosis. A stenotic valve can sometimes be stretched open using a procedure called balloon valvuloplasty. In this procedure, a catheter with a balloon at the tip is threaded through a vein or artery into the heart. Once across the faulty valve, the balloon is inflated, separating the valve cusps. This procedure does not require a general anesthetic and allows a quick recovery.
Two types of valves are available for replacement
Mechanical valves last for many years, but people with mechanical valves must take anticoagulants (warfarin) for the rest of their lives to prevent blood clots from forming in the valve. Taking an anticoagulant increases a person's risk of spontaneous bleeding, such as in their brain (see Overview of Hemorrhagic Stroke). Bioprosthetic valves generally deteriorate and require replacement after 10 to 12 years but do not require use of anticoagulants for more than 3 to 6 months after surgery. Some newer bioprosthetic valves are more durable.
Replacing a Heart Valve
Abnormal valves and all replacement valves can become infected. People with replacement valves need to take prophylactic antibiotics, which are antibiotics taken at certain times (for example, before some dental or medical procedures) in order to prevent bacterial infection of the valves (infective endocarditis).
Also, blood clots may form on replacement valves. The blood clots may partially block the valve or break loose and travel through the bloodstream to block arteries elsewhere in the body (for example, causing a stroke). Doctors use computed tomography and echocardiography to monitor replaced valves.