Key result
AF in moderate-to-severe AS is linked to ~24% higher mortality.
Why the study?
Outcomes in low-gradient AS are heterogeneous, and AF alters transvalvular hemodynamics and is linked to adverse prognosis. In Asian populations, smaller body size, lower stroke volume, and differing prevalence of AS and AF may further influence hemodynamic assessment and outcomes, warranting investigation in a large multicenter Asian cohort.
Does atrial fibrillation affect the prevalence of low-gradient aortic stenosis and clinical outcomes (all-cause mortality and aortic valve replacement) compared to sinus rhythm in Asian patients with moderate to severe aortic stenosis?
Cohort (n=5,218)
Yes
Does atrial fibrillation affect the prevalence of low-gradient aortic stenosis and clinical outcomes (all-cause mortality and aortic valve replacement) compared to sinus rhythm in Asian patients with moderate to severe aortic stenosis?
In Asian patients with moderate to severe aortic stenosis, atrial fibrillation is associated with lower transvalvular pressure gradients despite similar valve areas, leading to a higher prevalence of low-gradient AS, lower rates of AVR, and independently worse survival.
AF in moderate-to-severe AS was associated with higher low-gradient prevalence and mortality; extends observations to Asian cohorts but leaves management implications open.
Background Outcomes in low-gradient aortic stenosis (AS) are heterogeneous, and atrial fibrillation (AF) is linked to both adverse prognosis and altered transvalvular hemodynamics. Patients with AF more often present with a low-gradient phenotype, and gradients may vary by rhythm status, thereby unmasking true severity. In Asian populations, distinct features such as smaller body size, lower stroke volume, and differing prevalence of AS and AF may further influence hemodynamic assessment and prognosis. This study aimed to investigate the prevalence and outcomes of low-gradient AS in patients with AF using a large multicenter Asian cohort. Methods In this retrospective multicenter cohort study, 5,531 patients with moderate to severe AS diagnosed between 2008 and 2020 were stratified by rhythm at index echocardiography into rhythm (sinus rhythm vs. atrial fibrillation) and transvalvular mean pressure gradient (< 40 mmHg vs. ≥ 40 mmHg). Patients with moderate or greater mitral valve disease, significant aortic regurgitation, left ventricular ejection fraction <50%, or missing values for key variables, such as mean gradient, were excluded. After exclusion, 5,218 patients were included in the final analysis. Among them, 3,281 (62.9%) had severe AS defined as aortic valve area ≤ 1.0 cm2, and 2,910 (55.8%) were classified as low-gradient AS. By rhythm status, 4,723 (90.5%) were in sinus rhythm and 495 (9.5%) in atrial fibrillation. The primary outcome was defined as a composite of all-cause mortality and aortic valve replacement (AVR). Results Patients with AF were older and had a higher burden of comorbidities, including hypertension, diabetes, and prior cerebrovascular accident. They exhibited significantly higher left atrial volume index, higher E/e′, and higher estimated pulmonary artery systolic pressure. Although aortic valve area (AVA) was similar between groups (0.93 ± 0.26 vs.0.92 ± 0.27 cm2, p=0.608), peak aortic jet velocity, and mean gradient were significantly lower (35.9 ± 17.2 mmHg vs. 42.0 ± 19.5 mmHg, p <0.001) in the AF group. Thus, low-gradient AS was more prevalent in patients with AF than in those with sinus rhythm [66.3 vs. 54.7%, p <0.001]. During a median follow-up of 44.6 months, 1,795 patients (34.4%) died, and 2,632 (50.4%) underwent AVR. All-cause mortality was higher, and AVR was less frequently performed in the AF group; AF remained independently associated with increased mortality after multivariable adjustment (adjusted HR 1.24, 95% CI 1.08–1.43). Among patients with low-gradient AS, the AF group and the sinus rhythm group (Figure). Conclusion In patients with moderate to severe AS, low-gradient AS was more common in those with AF, and transvalvular pressure gradients were lower despite comparable aortic valve area. AF was associated with worse clinical outcomes, particularly in patients with low-gradient AS, in whom prognosis was significantly poorer compared with those in sinus rhythm.K-M survival
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Shin et al. (2026) conducted a cohort in Moderate to severe aortic stenosis with or without atrial fibrillation (n=5,218). Atrial fibrillation and low-gradient aortic stenosis (<40 mmHg) vs. Sinus rhythm and high-gradient aortic stenosis (≥40 mmHg) was evaluated on Composite of all-cause mortality and aortic valve replacement (AVR); adjusted effect reported for all-cause mortality (adjusted HR 1.24, 95% CI 1.08-1.43). Atrial fibrillation in moderate-to-severe AS increased low-gradient AS prevalence (66.3% vs 54.7%, p<0.001) and mortality (adjusted HR 1.24, 95% CI 1.08–1.43).
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