Aortic stenosis is a condition affecting the aortic valve—the valve positioned between the heart’s main pumping chamber and the aorta—causing it to narrow, or become stenotic. As one of the most common heart conditions, it is associated with older age and has serious implications. More than 1.7 million Americans over age 65 have severe aortic stenosis, and without valve replacement, as few as half survive beyond two years.
“We've known for many years that valvular heart disease is a different entity,” said Dr. Clyde Yancy, a past president of the American Heart Association and chief of the Division of Cardiology at Northwestern Memorial Hospital. “The extent to which that valve narrows may dictate the necessity for an intervention.”
When stenosis occurs, blood flow to the main artery and to the rest of the body is reduced or blocked. The more the aortic valve narrows, the harder the heart muscle must work to pump enough blood throughout the body. This stress on the heart can cause the left ventricle to become thicker and enlarged, ultimately weakening the heart muscle and potentially leading to heart failure or other serious problems.
Two decades ago, the long-time standard for intervention was surgical aortic valve replacement (SAVR). Even if it was the right decision and the operation went well, recovery from the operation was typically challenging. So, patients with the condition were often relegated to very conservative care, and without an intervention like surgery, a patient’s typical life expectancy is one to two years.
“But today, we have exciting new technologies that can make that entire process go much more smoothly, with much better outcomes,” Dr. Yancy said. “
To improve access and outcomes for aortic stenosis using paradigm-shifting treatment methods, healthcare leaders must first facilitate timely identification and diagnosis of the condition. An important way to achieve this is through better understanding of aortic stenosis symptoms among care providers, Dr. Yancy said.
Annual physicals, for instance, provide the opportune moment when, with sufficient awareness, a nurse practitioner, nurse or primary care physician can raise questions about stamina and exercise capacity, and inquire whether a heart murmur has ever been detected before, in effect lowering the threshold to proceed with cardiovascular imaging.
Beyond expanding awareness among providers and even patients, healthcare leaders have a responsibility to determine if and where there are inequities in access to the advanced treatment that exists today. Only with that foundational understanding can healthcare organizations optimize clinical pathways and referrals to connect patients with the right level of treatment at the right time, regardless of circumstance—including race, ethnicity and socioeconomic status.
A revolutionary treatment
About 20 years ago, a bold experiment took place in France that would dramatically change aortic stenosis treatment. By using an artificial valve (prosthesis), mounting it in a closed position on a catheter, positioning that catheter within the diseased aortic valve and finally, expanding the inserted valve into an open position, researchers came to a remarkable conclusion: it worked.
Through this procedure, called TAVR, an artificial valve is deployed into the native aortic valve and takes over the function of the diseased valve, working “so well,” said Dr. Yancy, "that we've gone from testing it in patients that weren't surgical candidates, showing that it worked and prolonged lives, to comparing it with surgery in people with severe disease and now moderate disease.”
While SAVR can still be done safely today, in the not-too-distant future, Dr. Yancy predicts TAVR might become the preferred operation for aortic stenosis in which all three small flaps of tissue (leaflets) that the aortic valve is made of are still present. Research shows that TAVR volumes have increased every year, with 72,991 performed in 2019 compared to 57,626 surgical aortic valve replacements performed. This is significant, as TAVR fills an unmet need for people with severe symptomatic aortic stenosis for whom SAVR poses a high risk. Because the minimally invasive procedure allows for inserting a new valve without removing the old, damaged valve, recovery time for patients is significantly shorter than surgical valve replacement that requires a larger opening.
Reduced recovery time translates to less time in the hospital, saving patients additional costs and improving their overall experience. For the health system overall, appropriately reducing length of stay for these patients frees up capacity for other patients to be treated as well as reduces spending. “We've gone from a very provocative experiment ... to an everyday standard of care that truly has changed the lives of millions of patients,” Dr. Yancy said.
Barriers to treatment utilization
Despite the introduction and growth of TAVR, the rate of valve replacement for patients with aortic stenosis remains concerningly low. In fact, less than 1 in 2 patients with known severe symptomatic aortic stenosis (SSAS) receive treatment within one year of symptom development, according to a 2022 study in the Journal of the American College of Cardiology. This is lower than the rate recorded two decades ago, when a Euro Heart study found that nearly one-third of patients with SSAS weren’t treated with SAVR, with many simply considered too old or sick for the procedure. For minorities, undertreatment is even more prevalent.
Widespread adoption of TAVR fills an unmet need for elderly patients previously excluded from SAVR, and indication has even expanded beyond that high-risk group to become an option for aortic stenosis patients at low, intermediate or high risk for standard valve replacement surgery.
So, why don’t higher numbers of people with aortic stenosis end up having valve replacement?
“Unfortunately, the growth of patients with indication far exceeds the growth of aortic valve replacement (AVR) utilization,” said Dr. Sammy Elmariah, chief of interventional cardiology and associate professor at UCSF Health. “So, despite the introduction and growth of TAVR, we remain behind in our ability to treat patients with SSAS.”
This vast underutilization of AVR must be widely understood as providers increasingly encounter patients who have aortic stenosis in clinical practice. In tandem, there is a need to appreciate that valve replacement is associated with improved survival across the spectrum of patients, regardless of subtype.
For clinicians, it’s important that providers understand there may be fairly significant narrowing of the valve even before the patient actually experiences any noticeable symptoms, according to Dr. Yancy. This means there may be indication to proceed with treatment even before the patient experiences more dramatic effects of the condition. Patients can present in various ways, making the condition more difficult to recognize.
Additional barriers to recognition, diagnosis and eventual treatment may relate to circumstances such as where a patient lives, or what their race is. Social determinants can be a major influencer of who is identified as a candidate for treatment.
“Early data points suggest that we are not applying these technologies in an equitable manner,” Dr. Yancy said.
“But we need data that are sufficiently robust —sufficient in number of observations and across the board, meaning in all cohorts—so that we can have certainty about whether or not an inequity is present.”
To continue improving access and outcomes for all aortic stenosis patients, Dr. Yancy explained there is also a need for deeper knowledge about the disease itself. Key questions include why the valve is vulnerable to this condition and whether vulnerability to deterioration is the same in all persons. Following research to these answers is the best way forward, he said.
“As much as we feel the compelling need to have unique programs that target certain populations, it's more important to have certainty—to have robust data acquired in all settings and all populations,” Dr. Yancy added.
Optimizing care for aortic stenosis
Knowing that SAVR and TAVR are effective at improving outcomes and mortality for patients with aortic stenosis—and that application of these options remains low among indicated patients—healthcare leaders have an obligation to facilitate improved recognition of the condition and efficient referral for treatment.
The American Heart Association's Target: Aortic Stenosis program, supported by Edwards Lifesciences, was launched with the aim of enhancing patient experience throughout the entire clinical journey for aortic stenosis—from symptom onset, diagnosis and follow-up, all the way through appropriate treatment and vigilant disease management. Meeting this aim will require both expanded awareness and further research around which optimal systems of care can be built.
“We want to understand the best diagnostic approach and spur additional scientific investigations,” Dr. Yancy said. “Our strategy is learning, deriving best practices and then deploying best practices.”
One thing that is clear at this point is that shared decision-making is immensely valuable in caring for patients with aortic stenosis. This means bringing together the patient, caregivers, patient advocates, the nurse practitioner, interventionalists, primary care physician, heart team, and even an agnostic physician to discuss the best path forward.
As for innovations related to aortic stenosis care, Dr. Yancy is excited about what lies ahead. His institution is one of a number that has started using artificial intelligence “to help guide a reasonably astute medical technician—but not necessarily someone trained to do echocardiography—to place the imaging probe on the chest.”
The technology is not yet ready for widespread clinical use, but it could help alleviate some early barriers to diagnosis that clinicians encounter today. So, while there is much work to do, there is also much to be hopeful about for a condition with implications for anyone who is aging or taking care of older individuals—parents, uncles, aunts, grandparents, and other loved ones.
“By starting with a high index of suspicion, through early screening, serial follow-up and consistent reporting of imaging data, we can identify the person who is likely to have mild disease or be at risk for disease,” Dr. Yancy said.“We can capture patients earlier, provide an intervention when it's indicated and allow best possible outcomes, as opposed to waiting for the condition to become severe.”
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