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Aortic valve area (continuity equation)

Calculates aortic valve area by continuity, the dimensionless index and peak gradient, and grades aortic stenosis.

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Check the population, units and version. The result shows the formula or classification; it does not make an automatic treatment decision.

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Method · Limits of application

EACVI/ASE 2017: VTI continuity equation; DVI; simplified Bernoulli 4 v²

Assessment of aortic stenosis in the EACVI/ASE 2017 recommendations is integrated: gradient, flow, ejection fraction and the quality of ventricular outflow tract assessment must be considered together. Low-flow or low-gradient situations require the specific assessment set out in the document. Calculated values alone do not reproduce this complete algorithm.

Conditions of use

Check the population, units, inclusion and exclusion criteria, and version in the original source. A result alone does not establish a diagnosis, discharge decision or prescription.

Documented parameters

Left ventricular outflow tract diameter · cm
Left ventricular outflow tract velocity–time integral (VTI) · cm
Aortic valve velocity–time integral (VTI) · cm
Peak aortic velocity (optional) · m/s
Body surface area (optional) · m²

2/2 reference cases checked. Numerical tests are not clinical validation.

Sources and documentation

Documented formula

Transcribed from the source or a recorded revision; this is not a clinical recommendation.

LVOT area = π × (diameter ÷ 2)²
Aortic valve area = LVOT area × LVOT VTI ÷ aortic VTI
Dimensionless index (DVI) = LVOT VTI ÷ aortic VTI
Peak gradient (simplified Bernoulli) = 4 × V²

References

Identifier: area-valvar-aortica

Original clinical content: Brazilian Portuguese.

Method version

EACVI/ASE 2017: VTI continuity equation; DVI; simplified Bernoulli 4 v²

area-valvar-aortica@native-2026-10-03+e07ead31e417

Source for the active edition

The bibliographic edition identifies the source. By itself, it proves neither full conformity of the formula nor clinical approval.

Synthetic cases checked (2)

Synthetic cases for checking the implementation, with no patient data.

Case 1

reference-001

Inputs

Left ventricular outflow tract diameter: 2 cm
Left ventricular outflow tract velocity–time integral (VTI): 20 cm
Aortic valve velocity–time integral (VTI): 80 cm
Peak aortic velocity (optional): 4 m/s

{
  "dvsve": 2,
  "vtivsve": 20,
  "vtiao": 80,
  "vmax": 4
}

Expected result

{
  "ava": 0.785,
  "dvi": 0.25
}

Actual result

{
  "ava": 0.7853981633974483,
  "dvi": 0.25,
  "lvot": 3.141592653589793
}

Case 2

reference-002

Inputs

Left ventricular outflow tract diameter: 2.2 cm
Left ventricular outflow tract velocity–time integral (VTI): 22 cm
Aortic valve velocity–time integral (VTI): 60 cm

{
  "dvsve": 2.2,
  "vtivsve": 22,
  "vtiao": 60
}

Expected result

{
  "ava": 1.3938,
  "dvi": 0.3667
}

Actual result

{
  "ava": 1.393819940642672,
  "dvi": 0.36666666666666664,
  "lvot": 3.8013271108436504
}

Code and reproducibility

This tool’s code on GitHub

Download code and tests

Sources, version and reproduction instructions

The code tests are technical checks. Clinical approval and professional translation review are recorded separately.

Relationship with cancer research

General context — relationship to be defined

A resource for general clinical contexts. This edition does not assign a specific oncological relationship; selecting it for a study requires a justified question, population and purpose.