Mitral Valve Area (MVA) Calculator
Estimates the mitral valve area based on five different methods to help with diagnosis of mitral stenosis.
Refer to the text below the tool for more information about the five MVA estimation methods and the result interpretation.
Mitral stenosis defines the mechanical obstruction in this blood flow due to different causes, such as thickening and immobility of the leaflets, thickening and fusion of the chorda tendinae or mitral annular and commissural calcification.
The assessment of mitral stenosis relies on echocardiographic measurements of the pressure gradient and on calculation of the mitral valve area. There are several estimation methods to determine MVA, such as the continuation equation, Gorlin equation, by PHT, by DHT or PISA (Proximal Isovelocity hemispheric Surface Area).
Mitral valve area may be interpreted in the light of mitral stenosis, as follows:
| Mitral Valve Area cm2 | Interpretation |
| 4.0 – 6.0 | Normal range |
| >1.5 | Mild stenosis |
| 1.0 – 1.5 | Moderate stenosis |
| <1.0 | Severe stenosis |
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Mitral Valve Area Explained
The mitral valve opens during left ventricular diastole to allow blood flow from left atrium to the ventricle. Normal mitral valve orifice has an area of about 4.0 – 6.0 cm2.
Mitral stenosis defines the mechanical obstruction in this blood flow due to different causes, such as thickening and immobility of the leaflets, thickening and fusion of the chorda tendinae or mitral annular and commissural calcification.
When the mitral valve area becomes less than 1 cm2, the subsequent increase in the left atrial pressure is then transmitted to the pulmonary vasculature, which will in turn result in pulmonary hypertension and eventually pulmonary congestion and edema. The left atrial enlargement due to chronic increases also predisposes to atrial fibrillation.
The assessment of mitral stenosis relies on echocardiographic measurements of the pressure gradient and on calculation of the mitral valve area. There are several estimation methods to determine mitral valve area, which are summarized in the table below:
| MVA estimation method | Formula | Variables |
| Continuity equation | LVOT Area = (1/2 x LVOT diameter)2 x π MVA = LVOT Area x (LVOT VTI / Mitral valve VTI) |
LVOT – left ventricular outflow tract LVOT VTI – left ventricular outflow tract velocity time integral Mitral valve VTI – mitral to aortic velocity-time integral |
| Gorlin equation | AVA = Cardiac Output / (Heart Rate x Systolic Ejection Period x 44.3 x √Mean Gradient) MVA = 0.85 x AVA |
Cardiac output Heart rate Systolic ejection period Mean valvular gradient |
| By PHT | MVA = 220/PHT | PHT – pressure half-time |
| By DT | MVA = 759/DT | DT – deceleration time |
| PISA | MVA = [ 2 x π x r2 x VA x (α/180) ] / Vmax | Radial distance from orifice when calculating proximal isovelocity hemispheric surface area Aliasing velocity Vmax – Peak mitral stenosis velocity by CW Angle (α) – Angle between two mitral leaflets on the atrial side (°) |
The continuity equation is based on the principle that the stroke volume that passes through the mitral valve area in diastole equals the stroke volume that passes through the left ventricular outflow tract during systole.
The pressure half-time (PHT) is the time between the maximum mitral gradient in early diastole and the time point where the gradient is half the maximum initial value. This can be determined by tracing the deceleration slope of the E-wave on Doppler transmitral flow. The decline in the velocity of diastolic transmitral blood flow is inversely proportional to mitral valve area.
The Vmax defines the flow profile of the mitral valve, which is typically the maximum velocity of the E wave. The deceleration time (DT) is the time from the Vmax to where the velocity is equal to zero. MVA is equal to 759 divided by DT.
MVA determined by Proximal Isovelocity hemispheric Surface Area (PISA) analyses the flow convergence on the atrial side.
Mitral valve area may be interpreted as follows:
| Mitral Valve Area cm2 | Interpretation |
| 4.0 – 6.0 | Normal range |
| >1.5 | Mild stenosis |
| 1.0 – 1.5 | Moderate stenosis |
| <1.0 | Severe stenosis |
References
Sattarzadeh R, Tavoosi A, Saadat M, Derakhshan L, Khosravi B, Geraiely B. Calculation of Mitral Valve Area in Mitral Stenosis: Comparison of Continuity Equation and Pressure Half Time With Two-Dimensional Planimetry in Patients With and Without Associated Aortic or Mitral Regurgitation or Atrial Fibrillation. Acta Med Iran. 2017; 55(11):696-704.
Baumgartner H, Hung J, Bermejo J, et al. Echocardiographic assessment of valve stenosis: EAE/ASE recommendations for clinical practice [published correction appears in J Am Soc Echocardiogr. 2009 May;22(5):442]. J Am Soc Echocardiogr. 2009;22(1):1-102.
Holen J, Aaslid R, Landmark K, Simonsen S, Ostrem T. Determination of effective orifice area in mitral stenosis from non-invasive ultrasound Doppler data and mitral flow rate. Acta Med Scand. 1977; 201(1-2):83-88.
Karp K, Teien D, Eriksson P. Doppler echocardiographic assessment of the valve area in patients with atrioventricular valve stenosis by application of the continuity equation. J Intern Med. 1989; 225(4):261-266.
American College of Cardiology/American Heart Association Task Force on Practice Guidelines; Society of Cardiovascular Anesthesiologists; Society for Cardiovascular Angiography and Interventions; ACC/AHA 2006 guidelines for the management of patients with valvular heart disease: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (writing committee to revise the 1998 Guidelines for the Management of Patients With Valvular Heart Disease): developed in collaboration with the Society of Cardiovascular Anesthesiologists: endorsed by the Society for Cardiovascular Angiography and Interventions and the Society of Thoracic Surgeons [published correction appears in Circulation. 2007 Apr 17;115(15):e409] [published correction appears in Circulation. 2010;121(23):e443]. Circulation. 2006; 114(5):e84-e231.
Gorlin R, Gorlin SG. Hydraulic formula for calculation of the area of the stenotic mitral valve, other cardiac valves, and central circulatory shunts. I. Am Heart J. 1951; 41(1):1-29.
Hatle L, Angelsen B. Doppler Ultrasound in Cardiology: Physical Principles and Clinical Applications. Philadelphia, Lea & Febiger, 1985.
Oh J, Seward JB, Tajik AJ. The Echo Manual 3rd edition. Lippincott, Williams, Wilkins. 2007.
Specialty: Cardiology
System: Cardiovascular
Abbreviation: MVA
Article By: Denise Nedea
Published On: July 16, 2020 · 12:00 AM
Last Checked: July 16, 2020
Next Review: July 16, 2025