Aortic Stenosis

An aerial view of the Hoover dam pictured left.

Aortic Stenosis. Know it. Love it. You will see it every day on the wards and in clinic.

Pathogenesis of Symptoms: large afterload leads to concentric left ventricular hypertrophy à high oxygen demand and ischemia (especially in subendocardium) à decreased compliance à fixed time of systole so when HR is high then diastole too short to fill ventricle àeventually leads to LV failure.

***if you do not remember how to perform one of the maneuvers below, please come find us ....we are happy to show you again***

Before you examine the precordium, have a look at:

• Carotid: parvus et tardus....a delayed and low volume carotid upstroke.
• JVP: look for prominent 'a' waves.

Precordium:

• Inspect: lateral displacement of the Point of Maximal Impulse (PMI)
• Palpate: the PMI may be displaced, greater in size, amplitude, and durations (longer than 2/3 of systole). You may feel a thrill.
• Auscultate: decreased or absent S2, may have an S3 or S4 present. Listen for a systolic ejection murmur at the right 2nd intercostal space. It should radiate past the clavicle towards both carotids. Time when the murmur peaks....later peaking correlates with increased severity of stenosis. The murmur intensity does not correlate with severity of stenosis.

Special Tests:

• Squatting: this increases pre-load, and will accentuate AS.
• Valsalva, or going from sit-to-stand will decrease pre-load and will minimize AS murmur.
• Apical Carotid Delay: palpate the precordial apex and the right carotid artery. Any delay in pulses is abnormal.
• Brachial Radial Delay: palpate the brachial artery and radial artery. Any delay between the two impulses is abnormal. Don't push too hard on the brachial artery as you will dampen the radial impulse!

Gallavardin phenomenon: this is when the AS murmur radiates to the apex with a more musical quality, imitating a murmur of Mitral Regurgitation.

Oy Vey....So what's the evidence for all this?

Here is a link to the classic JAMA paper, but it is summarized below....

-Rule Out AS (sensitive findings)

• Absence of systolic murmur
• Absence of murmur radiating to the right carotid

-Rule In AS (specific findings)

• Apical-carotid delay
• Slow rate of rise of the carotid artery
• Decreased intensity of S2
• Mid or late peaking murmur
• Brachio-radial delay

The same smart people from Toronto who wrote the above JAMA paper created another helpful bedside clinical prediction rule for diagnosing moderate to severe AS at this link.