Gorlin Formula Calculator

Calculate valve area and transvalvular flow from cardiac output, heart rate, flow period, pressure gradient, and valve type. Gorlin Formula Calculator supports clinicians, students, and cardiovascular researchers evaluating stenotic heart valves.

Highlights

  • Estimates stenotic valve area using the Gorlin equation.
  • Supports aortic, mitral, pulmonary, and tricuspid valves.
  • Uses cardiac output, heart rate, flow period, and mean pressure gradient.
  • Calculates transvalvular blood flow in mL/s.
  • Displays the applied Gorlin constant for the selected valve.

Table of Contents

  1. How Gorlin Formula Calculator Works?
  2. Practical Use Cases
  3. Accuracy and Limitations
  4. Quick Examples
  5. Frequently Asked Questions (FAQs)
  6. Cite This Calculator

How Gorlin Formula Calculator Works?

The Gorlin equation estimates the effective opening area of a stenotic cardiac valve from the blood flow passing through the valve and the mean pressure gradient across it. The calculator first estimates average transvalvular flow during the selected flow period, then uses the valve-specific Gorlin coefficient to calculate valve area.

Q=CO×100060×HR×T

Here, Q is transvalvular flow in mL/s, CO is cardiac output in L/min, HR is heart rate in beats per minute, and T is the valve flow period in seconds per beat.

A=QK×ΔP

In this equation, A is the estimated valve area in cm², K is the Gorlin coefficient for the selected valve, and ΔP is the mean transvalvular pressure gradient in mmHg. The calculator applies the following standard coefficients:


ValveGorlin coefficient
Aortic44.3
Pulmonary44.3
Mitral37.7
Tricuspid37.7

For example, with a cardiac output of 5 L/min, a heart rate of 70 bpm, a flow period of 0.33 s/beat, and a mean gradient of 10 mmHg, the estimated transvalvular flow is approximately 36.1 mL/s. Selecting an aortic or pulmonary valve gives an estimated area of approximately 0.26 cm², while selecting a mitral or tricuspid valve gives approximately 0.30 cm².

Practical Use Cases

Cardiologists and cardiovascular clinicians: Clinicians can estimate the effective area of an aortic, mitral, pulmonary, or tricuspid valve using measured cardiac output, heart rate, flow duration, and mean pressure gradient. The result can support hemodynamic assessment of suspected or known valve stenosis alongside echocardiographic and catheterization findings.

Cardiac catheterization teams: Hemodynamic teams can use the calculator during invasive assessment to examine how a measured pressure gradient and flow state correspond to an estimated valve area. This can help organize procedural data and support structured interpretation.

Medical and cardiovascular students: Students can change one input at a time to observe how cardiac output, heart rate, flow period, and pressure gradient influence transvalvular flow and calculated valve area. This provides a practical way to study the relationship between flow, gradient, and stenosis severity.

Cardiovascular researchers: Researchers can apply the same valve-specific coefficients across datasets when exploring stenotic valve hemodynamics, comparing flow conditions, or checking calculations in clinical studies and educational models.

Accuracy and Limitations

The calculator performs the standard Gorlin calculation using the entered cardiac output, heart rate, valve flow period, mean pressure gradient, and valve-specific coefficient, so its numerical result is only as reliable as those measurements. It assumes relatively steady flow and an appropriate mean gradient; irregular rhythms, rapidly changing loading conditions, significant regurgitation, low-flow states, inaccurate catheter measurements, or an incorrectly selected systolic or diastolic flow period can produce misleading valve areas. The result is an estimated effective orifice area and should not be used alone to diagnose stenosis, determine intervention, or replace comprehensive echocardiographic and invasive clinical assessment.

Quick Examples

Example #1: Severe Aortic Stenosis

Estimate the aortic valve area using resting hemodynamic measurements in a patient with suspected severe aortic stenosis.

Example #2: Mitral Valve Assessment

Calculate the effective mitral valve area for evaluation of suspected rheumatic mitral stenosis.

Example #3: Pulmonary Valve Evaluation

Estimate pulmonary valve area and transvalvular flow in a patient with suspected pulmonary valve stenosis.

Frequently Asked Questions

It estimates the effective opening area of a cardiac valve from transvalvular blood flow and the mean pressure gradient. It is commonly applied when assessing stenotic aortic, mitral, pulmonary, or tricuspid valves.

The equation can be applied to the aortic, mitral, pulmonary, and tricuspid valves. The appropriate valve-specific coefficient should be used for each assessment.

A smaller effective valve area generally suggests more significant narrowing, or stenosis. Interpretation should be made alongside symptoms, imaging findings, flow state, and other hemodynamic measurements.

The mean gradient reflects the pressure difference required to drive blood across a valve. Higher gradients often indicate greater obstruction, although the result also depends on blood flow and measurement conditions.

Low cardiac output, changes in heart rate, or altered valve-flow duration can influence the estimated area. Results should therefore be interpreted in the context of the patient’s overall hemodynamic state.

Cite This Calculator