What are the criteria for determining the severity of aortic stenosis (AS)?

Updated: May 07, 2019
  • Author: Xiushui (Mike) Ren, MD; Chief Editor: Terrence X O'Brien, MD, MS, FACC  more...
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Answer

The transvalvular gradient is dependent on the severity of obstruction and the flow across the valve. In patients with low cardiac output, the valvular stenosis may be severe even though the transvalvular gradient is low. To overcome this problem, 2D Doppler echocardiography can also provide a reliable estimation of aortic valve area (AVA). The echocardiographic criteria for assessment of aortic stenosis severity are outlined below, in Table 2.

Table 2. Criteria for Determining Severity of Aortic Stenosis (Open Table in a new window)

Severity

Mean gradient (mm Hg)

Aortic valve area (cm2)

Mild

<25

>1.5

Moderate

25-40

1-1.5

Severe

>40

< 1

(or < 0.5 cm2/m2 body surface area)

Critical

>80

<0.5


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