Heart valve disease (HVD) occurs when one or more of the heart’s four valves do not function correctly, disrupting the normal, one-way flow of blood. The valves act as one-way doors, opening and closing precisely with each heartbeat to ensure blood travels efficiently. When these structures are damaged, the heart must work harder to pump blood effectively. Over five million individuals in the United States alone receive this diagnosis each year.
The Mechanics of Heart Valve Disease
The heart contains four distinct valves—the aortic, mitral, tricuspid, and pulmonary—each controlling blood flow out of one of the heart’s four chambers. Heart valve disease commonly arises from two primary mechanical failures that impair this flow. Stenosis occurs when the valve flaps become stiff, thickened, or fused, preventing the valve from opening fully.
This narrowing of the valve opening restricts the amount of blood that can pass through, forcing the heart chamber behind the valve to generate higher pressure to push the blood forward. Over time, this increased workload can cause the heart muscle to thicken or enlarge, which may eventually lead to heart failure. The aortic and mitral valves, located on the heart’s high-pressure left side, are the most frequent sites of this type of damage.
The second form of failure is regurgitation, also called insufficiency or a leaky valve, which means the valve does not close completely. When a valve leaks, a portion of the blood flows backward into the chamber it just left. This backflow reduces the efficiency of the heart’s pumping action.
In the case of mitral regurgitation, for example, blood leaks back from the left ventricle into the left atrium during the heart’s contraction phase. This back-and-forth movement increases the volume of blood the heart must handle with each beat, adding strain and potentially leading to chamber enlargement. The mitral and aortic valves are most often affected by both stenosis and regurgitation.
Underlying Causes and Contributing Factors
Age-related degeneration is the most common cause of valve disease, particularly affecting the aortic valve. Over many years, calcium deposits accumulate on the valve leaflets, causing them to stiffen and narrow in a process called calcific aortic stenosis.
Infections represent another cause, notably infective endocarditis and rheumatic fever. Endocarditis is a bacterial infection of the heart’s inner lining and valves that can destroy valve tissue rapidly, often leading to severe regurgitation. While less common in the United States, rheumatic fever develops after an untreated strep throat infection and remains a worldwide cause of valve scarring.
Some individuals are born with malformed heart valves. The bicuspid aortic valve is the most frequent congenital defect, where the aortic valve has only two leaflets instead of the typical three. This structural difference causes abnormal blood flow, which accelerates wear and tear, often leading to stenosis or regurgitation much earlier in life.
Recognizing the Signs and Initial Assessment
Fatigue is a common complaint and often represents the first noticeable sign of reduced heart function. Patients may also experience progressive shortness of breath, particularly when engaging in physical activity or lying flat.
Reduced forward blood flow can lead to dizziness or fainting. The backup of blood pressure can cause fluid to accumulate in the legs, ankles, and feet, resulting in noticeable swelling. An irregular or fluttering heartbeat, known as palpitations, may also occur as the heart struggles to compensate for the valve dysfunction.
The first step in diagnosis is listening to the heart with a stethoscope to detect a heart murmur. A murmur is an extra or unusual swishing sound caused by turbulent blood flow through a narrowed or leaky valve. While a murmur alone does not confirm disease, it signals the need for further investigation.
The definitive diagnostic tool is the echocardiogram, which uses sound waves to create moving images of the heart’s structure and function. This non-invasive test allows doctors to directly visualize the valve leaflets, measure the size of the heart chambers, and assess the speed and direction of blood flow across the valves. Other supporting tests, such as an electrocardiogram (EKG) to check the heart’s electrical activity or a chest X-ray to look for fluid buildup, may also be used.
Management and Treatment Pathways
Treatment for heart valve disease is determined by the specific valve affected, the type and severity of the damage, and the patient’s overall health and symptoms. For mild cases without significant symptoms, the primary approach involves monitoring, often with periodic echocardiograms, and heart-healthy lifestyle changes. This strategy aims to manage risk factors like high blood pressure and high cholesterol to slow the disease’s progression.
Medication is often used to manage the symptoms and complications of valve disease. Diuretics help reduce fluid retention and swelling, while blood pressure medications can ease the strain on the heart muscle. These medications improve the heart’s function and the patient’s quality of life until a more definitive intervention is necessary.
When the disease becomes severe and symptoms worsen, surgical or minimally invasive intervention is required to repair or replace the faulty valve. Valve repair is preferred when possible, as it preserves the patient’s own tissue and may offer better long-term heart function. Repair techniques include patching holes in the leaflets or reinforcing the ring around the valve with an artificial band.
If repair is not feasible, the valve must be replaced with a prosthetic valve, which can be either mechanical or biological.
Mechanical Valves
Mechanical valves are made from carbon materials and are highly durable, often lasting a lifetime. However, they require the patient to take lifelong blood-thinning medication, such as warfarin, to prevent dangerous blood clots from forming on the valve.
Biological Valves
Biological valves, also called tissue valves, are typically constructed from animal tissue, such as from a pig or cow. These valves do not require long-term blood thinners but are less durable and tend to wear out over a period of 10 to 20 years, necessitating a second procedure, especially in younger patients. The choice between mechanical and biological valves is a highly individualized decision based on the patient’s age, lifestyle, and willingness to manage long-term anticoagulation.