Which statement best describes paradoxical low-flow low-gradient AS?

• A. Preserved LVEF with small LV chamber and SV index < 35
• B. Reduced LVEF with small LV chamber
• C. Preserved LVEF with large LV chamber
• D. Reduced LVEF with large LV chamber

Answer: (A)

Paradoxical low-flow low-gradient aortic stenosis is defined by severe valve narrowing with preserved left ventricular ejection fraction, but low stroke volume due to a small, thick-walled LV. The reduced flow results in a low transvalvular gradient even though the valve area is critically reduced. In this scenario the LV tends to be small and concentrically hypertrophied, which limits filling and stroke volume, hence the index of stroke volume (stroke volume index) falls below about 35 mL/m^2.

That’s why the statement describing preserved EF with a small LV chamber and a low stroke volume index best fits this pattern. The other descriptions involve reduced EF or a large LV chamber, which align with different AS phenotypes (systolic dysfunction or eccentric remodeling) and don’t capture the paradoxical low-flow, low-gradient profile.