A leaky heart valve happens when one or more of your heart’s four valves doesn’t close completely, allowing blood to flow backward instead of moving forward through the heart. The causes fall into two broad categories: structural damage to the valve itself, or changes in the heart muscle around the valve that pull it out of alignment. Among adults 65 and older, moderate or greater valve disease affects about 8% of the population, rising to nearly 15% by age 80 to 85.
Primary vs. Secondary Causes
Understanding the difference between these two categories matters because they involve completely different problems, even though the result (a leaky valve) looks the same on an echocardiogram.
In primary valve disease, something has physically damaged or deformed the valve’s leaflets, the thin flaps of tissue that open and close with each heartbeat. The cords anchoring those leaflets, or the muscles controlling them, may also be damaged. In secondary valve disease, the valve itself is structurally normal, but the heart chamber behind it has enlarged. That enlargement displaces the muscles attached to the valve and stretches the ring of tissue where the leaflets meet, preventing them from sealing shut. Heart failure and long-standing high blood pressure are common drivers of this secondary type.
Age-Related Wear and Calcification
The most common cause of a leaky valve in older adults is simple degeneration over decades of use. Valve leaflets thicken, stiffen, and accumulate calcium deposits. This process shares some similarities with how arteries harden: it involves fatty deposits, immune cells infiltrating the tissue, and proteins that promote calcification. The early stages may only cause mild stiffening, but over time, the buildup can prevent leaflets from closing fully or opening completely. Prevalence tells the story clearly. At ages 65 to 69, about 12% of people have at least mild-to-moderate valve disease. By ages 80 to 85, that figure reaches 31%.
Mitral Valve Prolapse
Mitral valve prolapse is one of the most common structural causes of a leaky valve, particularly on the left side of the heart. The mitral valve’s two leaflets become floppy and billow backward into the upper chamber during each heartbeat. In many cases, this causes no symptoms and no significant leakage. But in others, the leaflets fail to meet properly, and blood leaks backward with every contraction.
Most people with mitral valve prolapse were born with it, and it tends to run in families. Your risk increases with age, as the valve tissue becomes progressively more lax. Connective tissue disorders like Marfan syndrome and Ehlers-Danlos syndrome significantly raise the likelihood because they prevent the body’s connective tissue from developing normal strength and elasticity. Graves’ disease, scoliosis, certain types of muscular dystrophy, and a history of rheumatic fever also increase risk.
Heart Attacks and Acute Damage
A heart attack can cause sudden, severe valve leakage. The mitral valve is held in place by small muscles (papillary muscles) anchored to the wall of the lower left chamber. When a heart attack cuts off blood supply to one of these muscles, the muscle can weaken or rupture entirely. If it ruptures, the valve leaflets lose their anchor and flail freely, causing massive backward blood flow, pulmonary fluid buildup, and potentially cardiac shock. This is a surgical emergency. Even partial damage to these muscles or the cords connecting them to the leaflets can produce significant leakage that worsens over time.
Infections That Destroy Valve Tissue
Bacterial infections of the heart valves, known as infective endocarditis, can rapidly eat through valve tissue. Bacteria settle on the valve surface, often on a pre-existing area of minor damage, and form clumps of bacteria, immune cells, and clotting material. As the infection expands, it destroys the leaflet tissue, and can cause spontaneous rupture of the leaflets, the anchoring cords, or the papillary muscles. The damage is often irreversible and may require valve replacement surgery.
Rheumatic fever, triggered by untreated strep throat, causes a different kind of inflammatory damage. The immune system’s response to the strep bacteria cross-reacts with heart valve tissue, scarring and thickening the leaflets over time. Rheumatic valve disease accounts for roughly 30% of infections on native (non-prosthetic) heart valves, and it primarily affects the mitral valve. While rheumatic fever has become less common in developed countries, it remains a leading cause of valve disease worldwide.
Congenital and Genetic Causes
Some people are born with valve abnormalities that predispose them to leakage later in life. A bicuspid aortic valve, where the valve has two leaflets instead of the normal three, is present in about 1 to 2% of the population and is the most common congenital heart defect. The abnormal shape creates uneven stress on the leaflets, accelerating wear and calcium buildup.
Inherited connective tissue disorders weaken the structural proteins that give valves their flexibility and strength. Marfan syndrome makes the tissue in the aorta and heart valves weak and inelastic, leading to both aortic valve leakage and mitral valve prolapse. Related conditions like Loeys-Dietz syndrome, Ehlers-Danlos syndrome, and Turner syndrome carry similar risks, often also affecting the aorta itself. If you have a family history of any of these conditions, your valves may need periodic monitoring even if you feel fine.
High Blood Pressure and Aortic Problems
Chronically elevated blood pressure forces the heart to pump harder with every beat, gradually enlarging the left ventricle. As the chamber stretches, it pulls the valve structures out of alignment. High blood pressure can also widen the aorta itself, stretching the ring where the aortic valve sits and preventing its leaflets from meeting in the center.
An aortic dissection, a tear in the inner wall of the aorta, can cause sudden aortic valve leakage by disrupting the valve’s support structure. Chest trauma from car accidents or other injuries can produce similar acute damage.
Which Valves Leak Most Often
Among adults 65 and older, the tricuspid valve on the right side of the heart is the most commonly leaky, with moderate or greater regurgitation found in about 3.7% of that age group. Mitral regurgitation on the left side follows at 2.0%, and aortic regurgitation at 0.7%. Tricuspid leakage often develops secondary to other heart or lung problems that increase pressure on the right side of the heart, while mitral and aortic valve leakage more often stems from the structural and degenerative causes described above.
How Symptoms Develop Over Time
Mild valve leakage often produces no symptoms at all, and many people live their entire lives without knowing they have it. As leakage progresses to moderate or severe levels, the heart has to work harder to compensate for the blood flowing backward. Over months to years, this extra workload can enlarge the heart and weaken its pumping ability. Symptoms typically appear gradually: shortness of breath during physical activity, fatigue, heart palpitations, swelling in the legs and feet, and sometimes chest pressure or a persistent cough. Because these symptoms develop slowly, people often attribute them to aging or being out of shape before a diagnosis is made.
Severity is measured during an echocardiogram by looking at how much blood flows backward through the valve. In severe mitral regurgitation, more than 50% of the blood pumped forward leaks back through the valve with each beat, meaning the heart is doing more than double the work to maintain normal circulation.