Aortic Stenosis Severity Classification
| AVA (cm²) | iAVA (cm²/m²) | Classification |
|---|
| >1.5 | >0.85 | Mild AS |
| 1.0–1.5 | 0.60–0.85 | Moderate AS |
| <1.0 | <0.60 | Severe AS |
| <0.6 | <0.40 | Very Severe AS |
Flow (mL/s) = CO × 1000 / (HR × SEP)
AVA (cm²) = Flow / (44.3 × √ΔP̄)
BSA = 0.007184 × Wt⁰·⁴²⁵ × Ht⁰·⁷²⁵
iAVA = AVA / BSA
Clinical Notes:
• Gorlin formula may underestimate AVA at low flow states (paradoxical low-flow, low-gradient AS)
• Severe AS with low AVA but low gradient: use dobutamine stress echo or CT calcium scoring
• AVT ≥300 AU on CT: confirms severe AS even with discordant echo
• TAVR threshold: severe AS (AVA <1.0 cm²) + symptoms or EF <50%
