ECHONOMY Tools for Echocardiographic Calculations Muhamed Saric, MD, PhD
New York University
To calculate the aortic valve area
(AVA) using a simplified Gorlin equation. Original Gorlin formula calculates AVA from 5 parameters: cardiac output, mean pressure gradient, heart rate,
systolic ejection period and the constant 44.3.
Hakki and colleagues realized that 44.3 * SEP * HR is approximately 1000. If
the cardiac output is expressed in liters/minute (rather than in mL/min as
in Gorlin eq.), AVA can be calculated using only the cardiac output (CO) and the
square root of mean pressure gradient (MPG).
Make sure the cardiac output is
expressed in liters per minute!
Cardiac output (CO)
Mean pressure gradient (MPG):
Aortic valve area
Valve area = CO / sq root of MPG
Hakki A, Iskandrian A, Bemis C, Kimbiris D, Mintz G,
Segal B, Brice C. A simplified valve formula for the calculation of stenotic
cardiac valve areas. Circulation 1981;63(5):1050–5.