AM Report 2/14/17: Aortic Stenosis

Main etiologies of Aortic Stenosis

-Calcific/atherosclerotic: usually in patients >70, RF include HTN, Elevated TG, ESRD
Congenital: etiology in 50 % of patients <70, usually bicuspid AV
Rheumatic heart disease-usually associated with MV disease as well

TRIAD of Aortic Stenosis (not commonly seen)

-Heart Failure
-Syncope (usually with exertion when systemic vasodilation in the presence of a fixed SV causes BP to drop)

The most common presenting symptom is DOE followed by decreased exercise tolerance, and pre-syncope.

What to look for on echocardiography if you suspect AS

-Maximum instantaneous velocity across valve (Peak Velocity)
-Mean aortic valve gradient
Aortic Valve Area (AVA)

When is it considered SEVERE aortic stenosis?

-Mean gradient >40, Max Jet Velocity >4 m/s
AVA <1 cm2, or < 0.5 cm2/m2 BSA

When should you replace the valve (surgical replacement vs. TAVR)

-Anyone with SYMPTOMS (usually only in severe AS and can be subtle like decreased exercise tolerance)
Asymptomatic patients with severe AS with decrease in EF (EF<50 %)
-Asymptomatic patients with severe AS who are undergoing other cardiac surgery (eg: CABG)

Note that asymptomatic patients with severe AS do NOT need routinely need surgery.

What if AVA<1 but mean gradient is <40 and peak velocity <4?

This could be due to LOW FLOW-LOW GRADIENT Aortic Stenosis.

Diagnose it with a Dobutamine Echo

If TRUE Aortic Stenosis-Measured AVA will not change but the mean pressure gradient and transvalvular gradient will increase-these patients will benefit from replacement of the valve
If PSEUDO-severe stenosis, low cardiac output is due to myocardial dysfunction, and AVA will increase with dobutamine with minimal change in the gradient-likely will NOT benefit from replacement of the valve.

Medical treatment

-There is NO good medical treatment for severe Aortic Valve stenosis!
-Patients with severe AS can be considered to have a fixed afterload and pre-load dependent, so caution with use of diuretics, afterload reducers, and negative inotropes (CCB/BB) or you can cause them to syncopize!

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