Grading AS on Echocardiography

Parameter	Mild AS	Moderate AS	Severe AS
Aortic Valve Area (AVA)	> 1.5 cm²	1.0 – 1.5 cm²	< 1.0 cm²
Indexed AVA (AVA/BSA)	> 0.85 cm²/m²	0.6 – 0.85 cm²/m²	< 0.6 cm²/m²
Peak Aortic Jet Velocity	< 3.0 m/s	3.0 – 4.0 m/s	≥ 4.0 m/s
Mean Transvalvular Gradient	< 20 mmHg	20 – 40 mmHg	≥ 40 mmHg
Dimensionless Index (DI)	> 0.50	0.25 – 0.50	< 0.25
Aortic Valve VTI Ratio	> 0.50	0.25 – 0.50	< 0.25
Clinical Symptoms	Usually absent	May be present	Often present (dyspnea, angina, syncope)

Note: Always interpret AS severity in the context of flow status, LV function, and patient symptoms. Consider dobutamine stress echocardiography or CT calcium scoring in low-flow, low-gradient cases.

🔎 Notes:

• DI is especially useful when LVOT diameter is unreliable or in low-flow states (e.g., preserved EF but small stroke volume).

• Low-flow, low-gradient severe AS may have:

  • AVA < 1.0 cm²

  • DI < 0.25

  • But mean gradient < 40 mmHg due to low output — requires dobutamine stress echo or CT calcium scoring for confirmation.

• Always interpret in context with symptoms and LV function.