Table 2.

Echocardiographic diagnostic criteria for severe aortic stenosis.

Echocardiographic criterion	Method of measurement	Limitations
Peak jet velocity >4 m/sec	CW Doppler through aortic valve	Doppler measurement must be aligned with transvalve flow
Mean gradient >40 mmHg	AV CW using the Bernoulli formula	Doppler measurement must be aligned with transvalve flow
Aortic valve planimetry	Direct measurement of the valve orifice	Largely subjective, more difficult in the presence of calcification, poor reproducibility
AVA <1 cm2	Need to measure: LVOT area, AV VTI (CW) and LVOT gradient (PW)	Must ensure anatomical measurements are correct to avoid large errors
AVA index <0.6 cm2/m2	AVA/BSA	May overdiagnose severe AS in large individuals

AV = aortic valve; AS = aortic stenosis; AVA = aortic valve area; BSA = body surface area; CW = continuous wave; LVOT = left ventricular outflow tract; PW = pulse wave; VTI = velocity time integral.