Aortic stenosis is a condition where the heart’s aortic valve becomes narrowed, making it difficult for blood to flow out to the body. This valve narrowing forces the heart to work much harder, and over time, this extra effort can lead to serious complications affecting everyday life and overall health.
Understanding How Common Aortic Stenosis Is
Aortic stenosis becomes increasingly common as people grow older. The condition affects roughly 3% of people who are 65 years or older, and this number rises significantly with advancing age. Research shows that between 2% and 9% of individuals over 75 years old have severe forms of this valve disease.[3][12]
Before people develop symptoms, many don’t even know they have the condition. Studies reveal that calcific aortic sclerosis, which is the early stage of valve thickening and calcium buildup, appears in about 1% to 2% of people aged 65 or younger. However, this percentage jumps dramatically to 29% in those aged 65 and above.[3]
The disease doesn’t affect everyone equally. Men are more likely to develop aortic stenosis than women, and the condition is particularly common in elderly populations.[4] While aortic stenosis is most frequently seen in older adults, it can also appear in younger people who were born with certain heart valve abnormalities. In rare cases, children can be born with conditions that cause aortic valve stenosis to develop early in life.[4]
What Causes the Aortic Valve to Narrow
The root causes of aortic stenosis can be divided into conditions people are born with and those acquired later in life. Understanding these causes helps explain why different age groups develop the condition at different rates.
For people younger than 70 in developed countries, the most common cause is being born with a bicuspid aortic valve, which means the valve has only two flaps instead of the normal three. This abnormal structure makes the valve more prone to wear and calcium buildup over time.[3][5]
In older adults, the valve typically narrows due to age-related changes. Over many years, calcium deposits gradually accumulate on the valve’s leaflets, causing them to become stiff and thick. This process is similar to what happens in atherosclerosis, involving inflammation, lipid accumulation, and progressive calcification. The valve may open and close billions of times during a person’s lifetime, and this constant mechanical stress contributes to wear and tear.[1][12]
In developing countries, rheumatic heart disease remains a leading cause of aortic stenosis. This condition develops when untreated strep throat or scarlet fever progresses to rheumatic fever, which can damage heart valves. The damage may not become apparent until many years or even decades after the initial infection. When rheumatic disease affects the aortic valve, the commissures (where the valve leaflets meet) fuse together, leaving only a small central opening for blood flow.[3][6]
Several other less common causes exist. People with chronic kidney disease or end-stage renal disease may develop accelerated valve calcification due to disturbances in mineral metabolism. Rare conditions like Fabry disease, Paget’s disease of the bone, and familial hypercholesterolemia can also lead to aortic stenosis. Additionally, chest radiation treatment for cancer has been linked to faster calcium buildup on heart valves.[3][4][6]
Risk Factors That Increase Your Chances
Certain groups of people and specific health conditions increase the likelihood of developing aortic stenosis. Being aware of these risk factors can help with early detection and monitoring.
Age stands out as the single biggest risk factor. As people move past 65 years, the chances of developing valve calcification rise steadily. This age-related risk applies to everyone but becomes particularly significant after 75.[3]
Being male also increases risk, as men develop aortic stenosis more frequently than women. People born with heart valve abnormalities, especially a bicuspid aortic valve, face much higher risk at younger ages.[4]
Several cardiovascular risk factors contribute to the development and progression of valve disease. These include smoking, high blood pressure, high cholesterol levels, and chronic kidney disease. Autoimmune and inflammatory conditions such as lupus and rheumatoid arthritis have also been associated with increased risk.[4][8]
A history of rheumatic fever, particularly when it occurred during childhood, poses significant risk for developing aortic stenosis later in life. Although rheumatic fever is now rare in developed nations, it remains an important consideration in other parts of the world.[6]
Recognizing the Symptoms
One of the most challenging aspects of aortic stenosis is that it often develops silently over many years. During this long latent period, which can span 10 to 20 years, most people experience no symptoms at all. Survival during this asymptomatic phase is comparable to that of people without the condition. However, once symptoms appear, they signal that the disease has become more serious, and mortality increases significantly if left untreated.[3]
Symptoms typically begin gradually and often first appear during physical activity. Fatigue is frequently one of the earliest signs, with people noticing they tire more easily during normal daily activities. This can progress to the point where it disrupts regular routines and quality of life.[4]
Shortness of breath, medically called dyspnea, commonly develops as the condition worsens. People may first notice difficulty breathing during exercise or physical exertion, but in advanced cases, breathing problems can occur even at rest or when lying down.[4][6]
Chest pain or discomfort, known as angina, affects many people with aortic stenosis. This sensation might feel like tightness, squeezing, or pressure in the chest. The discomfort may spread to the neck, jaw, arm, or abdomen. Typically, this chest pain becomes more noticeable during physical activity when the heart needs to pump harder.[4][6]
Dizziness, lightheadedness, or fainting spells represent particularly concerning symptoms. These occur because the narrowed valve restricts blood flow to the brain and body. Some people may experience fainting without any warning signs, which can be dangerous and requires immediate medical evaluation.[5][6]
Additional symptoms can include heart palpitations, which means feeling unusually aware of your own heartbeat, and swelling in the feet, ankles, or lower legs. Some patients develop a cough, which may occasionally produce blood in severe cases.[4][6]
In children born with aortic stenosis, symptoms can differ from those in adults. Infants with severe cases may develop serious breathing problems within days or weeks of birth. Children with milder forms might show poor feeding, failure to gain weight adequately, or becoming easily tired during exertion.[6]
Ways to Prevent or Slow Disease Progression
While there is currently no medication proven to slow or reverse the progression of aortic stenosis once it has developed, certain lifestyle measures and preventive strategies may help reduce risk or identify the condition early.
Managing cardiovascular risk factors plays an important role in overall heart health. Quitting smoking, controlling high blood pressure, and managing high cholesterol through diet, exercise, and medication when necessary are all beneficial. Although these measures haven’t been definitively proven to prevent aortic stenosis, they support general cardiovascular wellness and may help reduce inflammation and calcium buildup in blood vessels and valves.[8]
Preventing rheumatic fever is crucial in areas where this condition remains common. This means promptly treating strep throat infections with antibiotics to prevent progression to rheumatic fever, which can damage heart valves. Early treatment of strep throat can protect the heart from long-term damage.[6]
Regular medical checkups become increasingly important as people age, especially after 65. During routine physical examinations, doctors can listen for heart murmurs using a stethoscope. A heart murmur is an abnormal sound caused by turbulent blood flow through a narrowed or damaged valve. Detecting a murmur early allows for monitoring and appropriate testing before symptoms develop.[9]
For people born with bicuspid aortic valves or other congenital heart conditions, regular monitoring by a cardiologist is essential. These individuals should have periodic echocardiograms even when feeling well, as they are at higher risk for developing significant stenosis at younger ages.[4]
People who have been diagnosed with mild or moderate aortic stenosis but don’t yet have symptoms should still watch for any changes. They should report new symptoms immediately to their doctor, as this could signal disease progression requiring more active intervention.[15]
How the Body Changes With Aortic Stenosis
Understanding what happens inside the body when the aortic valve narrows helps explain why symptoms develop and why the condition becomes dangerous over time.
The aortic valve sits between the heart’s left ventricle (the main pumping chamber) and the aorta, which is the body’s largest artery. In healthy conditions, this valve has three flexible leaflets that open widely during each heartbeat, allowing blood to flow easily into the aorta and then to the rest of the body. Between beats, the leaflets close tightly to prevent blood from flowing backward into the heart.[1]
When stenosis develops, the valve opening becomes progressively smaller. The velocity of blood flowing through the narrowed opening must increase to maintain adequate flow, and pressure builds up behind the valve in the left ventricle. The heart muscle must generate much greater force to push blood through the restricted opening.[3]
In response to this increased workload, the left ventricle undergoes hypertrophy, which means the muscle walls become thicker and stronger. This adaptation initially helps the heart maintain normal blood pressure and adequate blood flow throughout the body. For years, this compensatory mechanism can be successful, explaining the long asymptomatic period many patients experience.[12]
However, this thickened heart muscle requires more oxygen to function. The coronary arteries, which supply blood to the heart muscle itself, may not be able to provide enough oxygen, especially during physical activity. This mismatch between oxygen supply and demand explains why chest pain commonly occurs during exertion.[6]
The thickened heart muscle also becomes stiffer, making it harder for the left ventricle to relax and fill with blood between beats. This condition, called diastolic dysfunction, means the heart chamber doesn’t fill as completely as it should. The left atrium (the upper chamber that feeds blood into the left ventricle) must contract more forcefully to help fill the stiff ventricle adequately.[12]
As aortic stenosis continues to worsen, the compensatory mechanisms eventually fail. The left ventricle can no longer generate enough force to overcome the obstruction and maintain adequate blood flow. The heart’s pumping function begins to decline, a condition called systolic dysfunction. When combined with diastolic dysfunction, this leads to heart failure, where the heart cannot pump enough blood to meet the body’s needs.[12]
Blood may also back up into the lungs when the heart can’t pump effectively forward. This causes fluid to accumulate in the lung tissue, leading to shortness of breath and difficulty breathing, especially when lying flat. The inadequate forward blood flow also means less oxygen and nutrients reach vital organs throughout the body, causing fatigue, weakness, and in severe cases, fainting spells.[6]
The narrowed valve also creates turbulent, swirling blood flow patterns rather than smooth, organized flow. This turbulence is what creates the characteristic heart murmur that doctors can hear through a stethoscope. As stenosis becomes more severe, the murmur typically becomes louder and has distinctive qualities that experienced clinicians can recognize.[9]
