Moderate gradient severe aortic stenosis: diagnosis, prognosis and therapy

Area of Science:

• Cardiology
• Medical Imaging
• Valvular Heart Disease

Background:

• Severe aortic stenosis (AS) is typically defined by specific gradient and valve area criteria.
• A significant percentage of patients exhibit low-gradient AS, a heterogeneous condition with unclear pathophysiological mechanisms and variable prognosis.
• Discrepancy between aortic valve area and gradient measurements complicates AS severity assessment.

Purpose of the Study:

• To explore the diagnostic challenges and prognostic implications of low-gradient aortic stenosis.
• To highlight the role of various imaging modalities in differentiating low-gradient AS phenotypes.
• To discuss current guideline recommendations for managing patients with low-gradient AS.

Main Methods:

• Utilized color-Doppler echocardiography for hemodynamic assessment.
• Employed dobutamine stress echocardiography to evaluate ventricular response.
• Incorporated computed tomography (CT) for calcium scoring and magnetic resonance imaging (MRI) for detailed valve and myocardial characterization.

Main Results:

• Low-gradient AS encompasses heterogeneous clinical entities with distinct pathophysiological mechanisms.
• Prognosis varies significantly: classical low-flow AS has the worst outcome, followed by paradoxical low-flow AS, while normal-flow AS has a better prognosis.
• Diagnostic tools like echocardiography, CT, and MRI are essential for phenotyping low-gradient AS.

Conclusions:

• Accurate phenotyping of low-gradient AS using advanced imaging is critical for risk stratification.
• Guideline-directed treatment (surgical or percutaneous) is recommended for both classical and paradoxical low-flow low-gradient AS, tailored to individual patient factors.
• Understanding the heterogeneity of low-gradient AS improves clinical decision-making and patient management.