The chance that patients with severe aortic stenosis (AS) will receive aortic valve replacement (AVR) is worse than the flip of a coin, even a decade after the gamechanging transcatheter option became available, a new study suggests.
Of the study’s 6,150 patients with an indication or potential indication for AVR, 48% received the procedure at Massachusetts General Hospital and its partner institution Brigham and Women’s Hospital, both in Boston – both of which have active, high-volume transcatheter and surgical AVR (TAVR/SAVR) programs.
“Essentially, this is a best-case scenario. So, unfortunately, I think on the national level we are likely to see rates that are far worse than what we observed here,” senior author Sammy Elmariah, MD, PhD, Massachusetts General Hospital, told this news organization.
The volume of AVR increased more than 10-fold over the 18-year study period (2000 to 2017), driven by the exponential growth of TAVR, he noted. However, the graying of America led to an even greater increase in the number of patients with severe AS and an indication for AVR.
The study, led by Shawn X. Li, MD, MBA, of Mass General, wasin the March 8 issue of the Journal of the American College of Cardiology.
Previous research has provided equally compelling data on the undertreatment of AS, including a 2021 study using natural language processing (NLP) that found AVR use was just 35.6% within 1 year of diagnosis and varied wildly among managing cardiologists.
The present study used NLP tools to identify symptoms consistent with severe AS in the medical record coupled with echocardiographic data from 10,795 patients with severe AS (valve area <1 cm2). Patients were divided into four AS subtypes and then classified as having a class 1 indication (high-gradient AS with symptoms or reduced ejection fraction [EF]) or a potential class 2a indication (low-gradient AS with symptoms) for AVR.
Among patients with high-gradient AS and class 1 indication for AVR, 1 in 3 did not receive AVR over the study period, including 30% with a normal EF and 47% with a low EF.
In those with low-gradient AS, 67% with a normal EF and 62% with a low EF did not receive AVR. The low-gradient groups were significantly less likely to receive AVR both in the entire study period and in the more contemporary period from 2014 to 2017, despite the valvular heart disease guideline 2014 update indicating AVR was “reasonable” in patients with low-gradient AS – a 2a recommendation upgraded to class 1 in the most recent 2020 update.
In patients with a class 1 or potential class 2a indication, AVR was associated with a significantly lower risk of mortality in all four AS subgroups:
- High gradient/normal EF: 3% vs. 15%; adjusted hazard ratio, 0.42
- High-gradient/low EF: 16% vs. 72%; aHR, 0.28
- Low-gradient/normal EF: 5% vs. 14%; aHR, 0.73
- Low-gradient/low EF: 11% vs. 34%; aHR, 0.48; P < .001 for all
“I think what we need to do is change the paradigm, such that patients with a valve area that is less than or equal to 1 [cm2] is severe aortic stenosis until proven otherwise, and that essentially establishes a premise by which we default to treat these patients unless we can prove that it is in fact moderate,” Dr. Elmariah said.
Unfortunately, the opposite is currently true today, he said, and the default is not to treat and put patients through surgery or an invasive TAVR procedure unless physicians can definitively prove that it is severe AS. But they’re not always correct and don’t always have the ability to truly differentiate moderate from severe disease.
“The question, therefore, is ‘What do we do with those patients?’” Dr. Elmariah asked. “I think if a patient has symptoms, then we are obligated to intervene, given the stark difference in mortality that one sees when these patients go undertreated.”