Variation in Reader-Reported Severity of Paradoxical Low-Flow Low Gradient Aortic Stenosis: Observations from AaLarge Academic Health System

Introduction: Paradoxical low-flow low-gradient (PLFLG) aortic stenosis (AS) is frequently reported as non-severe AS on transthoracic echocardiogram (TTE) in clinical practice. It is uncertain how reader characteristics are associated with reporting of AS severity in patients with PLFLG AS. Methods: We identified all adults ≥ 18 years old from 9/2015-11/2019 with PLFLG AS on TTE within a large academic health system, and included only readers with ≥10 TTEs in this cohort. We determined the proportion of TTEs reported as either severe or moderate-severe and non-severe, and evaluated differences in reporting based on years of experience, volume of PLFLG AS studies interpreted per year, and quaternary vs. non-quaternary care site. We performed unadjusted and adjusted analyses using multivariable logistic regression. Results: Among 1329 patients meeting TTE criteria for PLFLG AS, only 37.3% were reported as severe/moderate-severe AS. Among 53 readers, the median proportion of patients reported as having severe/moderate-severe AS was 31.6% (25 th -75 th percentile 20.0%-50.0%, range 0.0-91.7%). There were differences in reporting between quartiles based on reader years of experience (33.3-40.9% across Q1-Q4 for proportion of patients reported with severe/moderate-severe AS; p = 0.01) but not volume (34.3-43.1% across Q1-Q4; p = 0.10). Quaternary care readers reported severe/moderate-severe AS for a much higher proportion of patients than non-quaternary care readers (64.3% [reader median 55.2%] vs. 30.9% [reader median 27.3%]; p < 0.001) (Figure), and this was the strongest reader-associated predictor of reporting severe-range AS (adjusted OR 7.6, 95% CI 5.1-11.5). Conclusions: Among patients with PLFLG AS, quaternary care TTE readers report severe AS much more commonly than non-quaternary care readers. Greater focus on TTE reporting of PLFLG AS at non-quaternary sites is likely needed to address underreporting of severe AS in this population.