Aortic Stenosis Stages A to D (ACC/AHA)

What the result means

Stage A

At risk: a bicuspid or congenitally abnormal valve, or aortic valve sclerosis, with a peak velocity below 2.0 m/s.

Stage B

Progressive. Mild at 2.0 to 2.9 m/s with a gradient below 20 mmHg; moderate at 3.0 to 3.9 m/s or a gradient of 20 to 39 mmHg.

Stage C1 and C2

Asymptomatic severe at 4.0 m/s or more, or a mean gradient of 40 mmHg or more. C1 with an ejection fraction of 50 percent or more, C2 below 50 percent.

Stage D1

Symptomatic severe at a high gradient: 4.0 m/s or more, or a gradient of 40 mmHg or more, with an area of 1.0 square cm or less.

Stage D2

Symptomatic severe at a low flow and low gradient: area 1.0 square cm or less, velocity below 4.0 and gradient below 40, ejection fraction below 50 percent.

Stage D3

Symptomatic severe at a low gradient with a normal ejection fraction: area 1.0 square cm or less AND indexed area 0.6 or less, with a stroke volume index below 35.

A low gradient is not a reprieve

D2 and D3 are severe disease below 4 m/s and below 40 mmHg. Reading the gradient alone calls both of them moderate, which is the error that matters here.

Velocity OR gradient

The two are an OR, so the more severe of them decides. Where they disagree the tile names the one that decided.

Very severe

A velocity of 5 m/s or more, or a mean gradient of 60 mmHg or more, sits within the severe range as very severe stenosis.

Confirming D2

Low-dose dobutamine stress echocardiography separates true severe from pseudo-severe: true severe keeps an area of 1.0 square cm or less with a velocity reaching 4 m/s at any flow rate.