Classification of AS based on 2017 European Society of Cardiology guidelines
| Classification of AS | AVA | MPG | LVEF | SVI |
| High gradient | ≤1 cm2 | ≥40 mm Hg | Irrelevant | Irrelevant |
| Low flow, low gradient with reduced ejection fraction | ≤1 cm2 | <40 mm Hg | <50% | ≤35 mL/m2 |
| Low flow, low gradient with preserved ejection fraction | ≤1 cm2 | <40 mm Hg | ≥50% | ≤35 mL/m2 |
| Normal flow, low gradient with preserved EF (likely moderate AS) | ≤1 cm2 | <40 mm Hg | ≥50% | >35 mL/m2 |
Adapted from Baumgartner et al.5
AS, aortic stenosis; AVA, aortic valve area; MPG, mean pressure gradient; LVEF, left ventricular ejection fraction; SVI, Stroke Volume Index.