The Cardiovascular
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Aortic valve area (continuity equation)

Aortic valve area and indexed area for grading aortic stenosis.

Aortic valve area (continuity equation)
LVOT diameter
LVOT VTI
cm
Aortic valve VTI
cm
Body surface area (optional)
m²
Complete the fields above to see the result.

When to use

  • Grading aortic stenosis severity, especially when transvalvular gradients may be misleading (low flow, low ejection fraction, or high output).

Formula

AVA = (LVOT CSA × LVOT VTI) / AV VTI, where LVOT CSA = π × (LVOT diameter / 2)².

Pearls and pitfalls

  • The dimensionless index avoids LVOT diameter measurement altogether and is useful when the LVOT cannot be measured reliably.
  • In low-flow low-gradient aortic stenosis with reduced ejection fraction, dobutamine stress echocardiography distinguishes true-severe from pseudo-severe stenosis.

References

  1. Baumgartner H, et al. Recommendations on the Echocardiographic Assessment of Aortic Valve Stenosis: A Focused Update. J Am Soc Echocardiogr. 2017;30(4):372–92.