Outcome of low-gradient aortic stenosis in patients with atrial fibrillation: insights from a multicenter cohort
Y Shin, K Kim, S Lee, J Seo, J Lim, S J Park, S P Lee, C Y Shim, G R Hong, J W HaAbstract
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