VIDEO: AHA says aortic stenosis is undertreated and underdiagnosed

With the introduction of transcatheter aortic replacement (TAVR), more patients are coming forward to get consultations on aortic replacements, and the patient population was found to be much larger than previously thought. But how large is the actual population of patients with AS is still not known, and it appears now that it may be a significantly underdiagnosed and undertreated cardiac condition. 

"The AHA Target AS initiative launched three years ago as a pilot program, and the issue it is trying to address is the undertreatment of patients with severe, symptomatic aortic stenosis," Lindman said. "What we have learned through several publications recently is that 50% of more these patients are not treated with an aortic valve replacement." 

He said there is certainly a small percentage of these patients where it would be futile to treat them, but he said most would likely benefit with a better quality of life if they received a valve replacement.

"We have seen in studies that the lack of performing an aortic valve replacement is associated with a marked increase in mortality over the subsequent years," Lindman explained.

So, at the AHA 2022 meeting, the Target AS initiative was formerly launched to encourage hospitals and health systems to take a more active roll in addressing this underdiagnosis and undertreatment of AS patients. Lindman said there has been an over emphasis on the quality markers of the procedures for AS, rather than looking at the metrics of detecting AS in the population and how many of those patients receive treatment. 

He said health systems need to create more of an infrastructure to detect these patients, mainly through use of echocardiograms. Adding additional measures or field in echo reports that can help determine AS risk scores would be helpful it better identifying these patients. Gathering data on AS patients earlier, including creation of a registry, to track these patients after detection, would greatly help fill the data gap to better understand when it is best to intervene with a valve replacement. It is believed earlier intervention might be better, rather than waiting until a patient is very sick, but more clinical information is needed about the population overall.  

TAVR halo-effect has helped boost overall aortic replacement procedures, including surgery

Since the introduction of transcatheter aortic valve replacement a decade ago, TAVR volumes rapidly rose and now make up more than 80% of aortic valve replacement procedures. There was an expectation TAVR would greatly reduce the number of aortic valve surgeries, but at many centers, numbers have stayed nearly the same or risen. 

Prior to TAVR, many patients were not referred to surgeons because patients did not want surgery, or doctors feared the patient was too frail for surgery. However, with the advent of minimally invasive TAVR, this has changed the referral patterns and many more more patients than expected emerged and greatly expanded what was previously thought to be a much small treatable patient population. 

"We often refer to this as the halo effect of TAVR," Lindman said. "Because transcatheter valve replacement has come onto the scene and trials have shown it is safe and effective, now patients that primary care physicians and some general cardiologists would have written off in terms of referring for a valve replacement, they are now seeing that this is an option and they send them." 

While many patients referred do get TAVR, Lindman said for various reasons, including patient anatomy or age, heart teams deem them better surgical candidates. 

More echocardiograms are needed to catch more aortic stenosis patients

"Overall, the number of patients with aortic stenosis is increasing, but nonetheless, there are even more who may warrant valve replacements who are not getting it," Lindman explained. "There is undoubtedly an underdetection problem. We know we are undertreating the number of people who we know have at the disease, but when you consider the iceberg under the surface, and the fact that there are people who have the disease that we actually do not know know have it, because the diagnosis is made after they have an echocardiogram."  

He said there is still an overreliance on using a stethoscope to listen for faint sounds of early aortic stenosis, when a cardiac ultrasound is much more sensitive in detecting AS. "So we are missing aortic stenosis cases simply because we are laying on the stethoscope or relying on ascertaining the symptoms through a patient history. If that is all we are relying on, then we are missing some AS out there."