Mitral Valve Area Calculator - PHT, Continuity, Gorlin and Hakki MVA

A mitral valve area calculator turns a small set of echo or cath measurements into a single valve area in cm^2, with an indexed value and a severity band that follows the 2020 ACC/AHA valvular heart disease guideline. It is built for patients worked up for mitral stenosis, for clinicians who want a quick reproducibility check on a reported MVA, and for trainees who want the PHT, continuity, Gorlin, and Hakki formulas on one screen.

• • Echo PHT workflow: drop in a Doppler pressure half-time and BSA and read the area, the indexed value, and the severity band on the same screen.
• • Echo continuity workflow: drop in LVOT diameter, LVOT VTI, and mitral VTI from a transthoracic echo and read the area returned by the continuity equation.
• • Cath workflow: drop in cardiac output, heart rate, diastolic filling period, and mean transmitral gradient from a cath pullback and read the Gorlin and Hakki areas.
• • Teaching and review: use the side-by-side formula display to teach PHT 220, continuity, Gorlin constant 31, and Hakki in one place.

MVA is the most common measurement of how narrowed the valve is. It pairs with mean transmitral gradient and pulmonary pressure, and the area converts into the 2020 ACC/AHA severity bands.

The closest echo and cath peer is the Aortic Valve Area Calculator, which uses the same continuity, Gorlin, and Hakki workflow for the aortic valve.

The calculator works in three short steps. It reads the method toggle, applies the chosen formula, and divides the area by the body surface area to return an indexed value plus the ACC/AHA severity band.

• PHT: pressure half-time in ms across the valve from continuous-wave Doppler.
• LVOT_diameter, LVOT_VTI, MV_VTI: LVOT diameter in cm and the LVOT and mitral velocity-time integrals in cm.
• CO, HR, DFP, MG: cardiac output in L/min, heart rate in bpm, diastolic filling period in ms, and mean transmitral gradient in mmHg.
• BSA: body surface area in m^2 from the Mosteller formula, used to index the result.

The PHT branch is the empirical constant 220 divided by the pressure half-time. It was derived from a regression of cath valve area against Doppler PHT in 42 patients and has been the workhorse echo method since the late 1970s.

The continuity branch treats the LVOT as a circle with cross-sectional area pi d squared over four and uses the VTI ratio at the LVOT and the mitral valve, on the assumption of no significant MR or AI.

The cath branch uses the mitral Gorlin constant 31 (different from the aortic 44.3) and adds the mean gradient. Hakki drops the HR and DFP terms.

According to Hatle 1979 Circulation, the Doppler pressure half-time method yields mitral valve area in cm^2 as 220 divided by the pressure half-time in milliseconds.

When the cath inputs need a stable heart rate, the ECG Heart Rate Calculator confirms the rate from an ECG strip.

Four concepts drive the result. Naming them keeps the MVA result from being read as a single lab number, which it is not.

The most important distinction is the method. Pressure half-time is the workhorse echo approach; continuity is useful when planimetry is not feasible and there is no significant regurgitation; Gorlin is the cath-lab reference; Hakki is the cath shortcut.

Indexed valve function shares the body-surface-area denominator with lipid risk, and the LDL Calculator returns an LDL from total cholesterol, HDL, and triglycerides for the ASCVD picture.

The form works from a small set of clinical measurements. Each input should reflect the measurement as it was taken, not an idealised version.

1. 1 Choose the method: pick Echo PHT for a Doppler pressure half-time, Echo continuity for an LVOT diameter and VTI plus a mitral VTI, or Cath for cardiac output and a mean transmitral gradient.
2. 2 Enter the matching inputs: for Echo PHT, type the pressure half-time in ms. For Echo continuity, type the LVOT diameter, LVOT VTI, and mitral VTI. For Cath, type the cardiac output, heart rate, diastolic filling period, and mean gradient.
3. 3 Pick the cath formula when needed: for Cath, leave the default on the full Gorlin formula, or switch to Hakki when only cardiac output and mean gradient are available.
4. 4 Enter the body surface area: type a BSA in m^2 (Mosteller from height and weight) so the calculator returns the indexed MVA.
5. 5 Read the result panel: look at the MVA, the indexed value, the severity band, the indexed severe label, and the active method together.

A reader with an echo PHT of 150 ms and BSA 1.9 m^2 can read the MVA, the indexed value, and the severity band together.

The cath inputs sit alongside systemic blood pressure, and the Blood Pressure Calculator confirms a current systolic and diastolic reading, since hypertension often coexists with mitral stenosis.

Calculating the area from a small set of measurements has several practical benefits over running the math by hand.

• • Three methods, one form: a single switch moves the form between Echo PHT, Echo continuity, and Cath, covering both clinical workflows.
• • Body-surface-area indexed value: the indexed MVA is returned on the same row, so small-body-size patients get the more sensitive 1.0 cm^2/m^2 severe-by-index label.
• • Severity band built in: the severity band follows the 2020 ACC/AHA thresholds (severe at or below 1.5 cm^2, very severe at or below 1.0 cm^2).
• • Active method disclosure: the result panel labels the method that produced the number, so the reader knows whether the value came from PHT, continuity, Gorlin, or Hakki.
• • Gorlin and Hakki in cath: the cath branch keeps both the full Gorlin constant 31 form and the Hakki shortcut, so a reader can check the two cath estimates against each other.

The same form works for self-tracking between echo studies and for shared tracking with a cardiology clinic that wants a quick reproducibility check on the valve area.

For the indexed value, the BSA step pairs with the Body Surface Area Calculator, which returns the Mosteller BSA from height and weight for that step.

Several factors shape the result. The most important ones sit inside the entered form, and a small set of caveats belong outside the form.

• • The PHT 220 constant assumes a linear relationship between pressure half-time and valve area. In severe aortic insufficiency, a stiff left ventricle, or immediately after valvuloplasty, the constant drifts and planimetry or continuity is preferred.
• • The result is a planning estimate, not a diagnosis. The clinical decision sits with the cardiology team and should consider symptoms, left-atrial size, pulmonary pressure, valve morphology, and exercise testing.

The 2020 ACC/AHA guideline pairs the valve area with mean transmitral gradient and pulmonary pressure in the severe range, so a value above the severe band is reassuring only when the gradient and pressure agree.

According to 2020 ACC/AHA Valvular Heart Disease Guideline, severe mitral stenosis is defined as a mitral valve area at or below 1.5 cm^2 and very severe mitral stenosis as a mitral valve area at or below 1.0 cm^2.

According to Gorlin and Gorlin 1951 Circulation, the empirical constant for the mitral valve in the Gorlin orifice-area equation is approximately 31, distinct from the aortic constant 44.3.

Indexed valve function shares the body-surface-area denominator with kidney function, and the GFR Calculator returns an eGFR indexed to 1.73 m^2, useful alongside an MS workup before contrast imaging.