medwireNews: Patients with untreated aortic stenosis (AS) have an increased risk for mortality irrespective of severity, yet aortic valve replacement (AVR) rates remain low, study findings indicate.
Philippe Généreux (Morristown Medical Center, New Jersey, USA) and team found that mortality risk increased incrementally across the spectrum of AS severity, “suggesting the need for earlier diagnosis, closer follow-up, and potentially earlier intervention.”
The researchers used a natural language processing algorithm to categorize the severity of AS in a large real-world dataset comprising 595,120 individuals older than 18 years of age from 24 US hospitals. Mortality data were obtained from hospital records, and the study assessed outcomes using Kaplan–Meier estimates over 4 years. The primary endpoint was untreated all-cause mortality, while the secondary endpoint was time to AVR.
In all, 70,778 patients were diagnosed with AS, with 5.8% classified as having mild AS, 1.0% mild-to-moderate AS, 2.4% moderate AS, 0.6% moderate-to-severe AS, and 2.0% severe AS. The remaining 524,342 patients did not have AS.
The findings, published in the Journal of the American College of Cardiology, show that 4-year unadjusted all-cause mortality rates increased in line with untreated AS severity, from 13.5% among individuals with no AS, to 25.0% among those with mild AS, 29.7% among those with mild-to-moderate AS, 33.5% among those with moderate AS, 45.7% among individuals with moderate-to-severe AS, and 44.9% for those with severe AS.
After adjustment for age, sex, and various comorbidities, AS of any severity was significantly associated with increased risk for mortality, with hazard ratios ranging from a respective 1.27 and 1.48 with mild and mild-to-moderate AS to 1.95 and 2.09 with moderate-to-severe and severe AS.
The researchers highlight that there was a relatively high proportion of people, at 13.4%, who had “intermediate” diagnoses, such as mild-to-moderate or moderate-to-severe AS, a finding they say illustrates “the challenges of precise AS severity diagnosis in a real-world setting and in the community.”
Moreover, “the mortality of patients receiving those ‘intermediate’ diagnoses exhibit similar mortality as the next most severe grade of AS,” they stress and propose that “it might be appropriate and more practical to ‘upgrade’ patients to a higher severity of AS when one severity criterion coexists with a less severe one,” so that referral and treatment are not delayed.
Despite the associated increased risk for mortality, AVR rates for AS were low over the 4 years, at 36.7% in patients with moderate-to-severe AS and 60.7% in those with severe AS.
“Better understanding of the reasons driving this undertreatment is needed,” say Généreux et al.
In a related editorial comment, Eugene Braunwald (Brigham and Women’s Hospital, Boston, Massachusetts, USA) states that the proportion of people not undergoing AVR is “excessive, especially in the current era, in which both surgical and transcatheter AVR are effective and impose low risk.”
He says: “This large contemporary database reinforces the position that many patients with AS are currently undertreated even in experienced centers, a deficiency that […] must be corrected.”
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J Am Coll Cardiol 2023; 82: 2101–2109
J Am Coll Cardiol 2023; 82: 2110–2112