Severe Low Flow Aortic Stenosis With Preserved Ejection Fraction: Latest Diagnostic and Therapeutic Approach

Paradoxical low-flow, low-gradient aortic stenosis (pLF-LG AS) represents a distinct phenotype of severe aortic stenosis characterized by a reduced aortic valve area with low transvalvular gradients despite preserved left ventricular ejection fraction and reduced forward flow. It is associated with concentric remodeling, impaired longitudinal systolic function, and diastolic dysfunction, resulting in reduced stroke volume and potential underestimation of disease severity. This state-of-the-art review synthesizes evidence from registries, observational studies, randomized trial subgroup analyses, guideline recommendations, and mechanistic investigations. Diagnosis requires an integrative multimodality approach combining Doppler echocardiography, low-dose dobutamine stress echocardiography, and computed tomography-based aortic valve calcium scoring to differentiate true-severe from pseudo-severe disease. In symptomatic patients with confirmed severe pLF-LG AS, aortic valve replacement is associated with improved survival, although the magnitude of clinical benefit remains variable. Transcatheter aortic valve implantation represents an effective treatment option in selected patients; however, phenotype-specific comparative data versus surgical valve replacement remain limited. Overall, pLF-LG AS requires accurate diagnostic confirmation and individualized, heart team-guided management to optimize clinical outcomes.