Finding and fixing a stiff, narrowed aortic valve

The first clue may be a whooshing sound your doctor hears while listening to your heart with a stethoscope. Known as a heart murmur, it suggests abnormal blood flow in the heart's valves. In older adults, a common cause is aortic stenosis - a stiff, narrowed aortic valve.

Your aortic valve regulates the flow of blood from the heart to the rest of the body. A narrowed valve limits normal blood flow and forces the heart to work harder. Left untreated, severe aortic stenosis can lead to heart failure and sudden death.

"Aortic stenosis is a progressive disease, so early detection and close monitoring is important," says Dr. Yee-Ping Sun, a cardiologist at Harvard-affiliated Brigham and Women's Hospital. The good news: treatment is available and researchers are looking for new treatments, including a recent study that explored the potential benefits of proactive valve replacement.

What causes aortic stenosis?

Aortic stenosis commonly affects older adults due to calcium deposits and scar tissue building up on the valve. While the underlying cause of that buildup is often a mystery, it is not connected to the amount of calcium people consume. However, elevated blood levels of a fatty particle called lipoprotein(a), or Lp(a), are associated with aortic stenosis that occurs before age 70, says Dr. Sun. Ongoing trials are investigating that connection, while others are testing new medications to lower Lp(a), which is also closely linked to early heart attacks (those occurring before age 65 in men and before age 55 in women).

Age is the most significant risk factor for aortic stenosis. Among people in their 60s, the prevalence is just over 1%, but it rises to nearly 10% for those 80 and older. The problem can develop much earlier in people who are born with an uncommon valve structure that is more prone to calcium buildup (see "What is a bicuspid aortic valve?").

Finally, certain health problems may increase a person's odds of aortic stenosis, including kidney disease, hyperparathyroidism, and inflammatory disorders such as rheumatoid arthritis, lupus, and systemic sclerosis. Having radiation therapy to the chest, usually done to treat lymphoma, is another risk factor.

Aortic stenosis symptoms and diagnosis

Simply having a heart murmur isn't enough for a doctor to be sure you have aortic stenosis. You also need a heart ultrasound (echocardiogram) to confirm the diagnosis or identify another cause. Sometimes the condition is discovered by chance during an echocardiogram done for another reason. The most common symptoms - shortness of breath, fatigue, and lightheadedness, especially during exertion - have many possible causes, so they're not helpful for pinpointing the problem. Fainting, as well as chest tightness or discomfort, can also occur. However, some people with moderate or even severe stenosis have no noticeable symptoms.

Monitoring and treating aortic stenosis

If an echocardiogram reveals only mild stenosis, your doctor may recommend a repeat ultrasound every three to five years. Moderate stenosis should be checked yearly. Currently, there are no medications known to slow the progression of aortic stenosis, but Dr. Sun and his colleagues are involved in a large trial investigating a promising candidate called ataciguat.

Once you start experiencing symptoms from severe aortic stenosis, you need a new aortic valve. For some people, including younger patients and those with certain anatomical issues, surgery is the best option. But growing numbers of people are considered good candidates for transcatheter aortic valve implantation (TAVI), a less invasive procedure in which the surgeon delivers a new valve to the heart through a catheter inserted into an artery at the top of the thigh.

In fact, TAVI is now being offered to people with severe aortic stenosis but no symptoms, based on a 2024 study. "In people who are over 65, having an early TAVI does not help you live longer. But it's a reasonable alternative to waiting for symptoms to appear, given that most people with severe aortic stenosis end up needing a valve replacement within a few years," says Dr. Sun.

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