Aortic Stenosis

Aortic Valve (AV)

• • Usually tricuspid, composed of fibrous skeleton, 3 cusps, and sinuses of Valsalva

  • Free edge of each cusp is concave and thicker, with fibrous node at midpoint

  • Eddy currents in sinuses of Valsalva prevent occlusion of coronary ostia during systole

  • Cusps fall closed and coapt, supports ejected column of blood during diastole

  • Coronary arteries arise from 2 of 3 sinuses of Valsalva

Aortic Stenosis (AS)

• • Can be subvalvular, valvular, or supravalvular

  • Etiology in adult: Congenital unicuspid, bicuspid valve; congenital subvalvular or supravalvular stenosis; rheumatic heart disease; or degenerative fibrosis and calcification (most common)

  • LV outflow obstruction leads to concentric LV hypertrophy: decreased diastolic compliance, maintained ejection fraction (EF)

  • Atrial systole important for LV filling

  • Atrial fibrillation may precipitate congestive heart failure (CHF)

  • LV hypertrophy leads to increased myocardial oxygen consumption, coronary artery disease (present in 25-50%), more myocardium at jeopardy

Epidemiology

• • Causes of valve disease

  • -Rheumatic carditis (most common)

    -Valve collagen degeneration

    -Infection

    -Less common causes include collagen-vascular disease, tumors, carcinoid, and Marfan syndrome

  • Valvular heart disease: 89,000 hospital discharges in 1998

AS

• • Likely congenital if patient is < 30 years old

  • Likely bicuspid valve if patient is 30-65 years old

  • Likely degenerative if patient is > 65 years old

Symptoms and Signs

• • Most asymptomatic for many years

  • Triad: Angina, syncope, CHF

  • Aortic valve gradient > 50 mm Hg, or valve area < 1 cm2 usually symptomatic

  • Angina from inadequate oxygen delivery

  • Syncope usually exertional

  • CHF is late finding and ominous sign

  • Narrowed pulse pressure

  • Decreased systolic pressure (parvus et tardus)

  • Harsh midsystolic murmur: second intercostal space along left sternal border, radiating to carotids, not axilla or apex

  • 25-50% also have aortic regurgitation murmur

Laboratory Findings

• • ECG: LV hypertrophy

Imaging Findings

• • Chest film: Heart usually normal size (may be dilated if CHF present), post-stenotic aortic dilation, calcified aortic valve

  • Transesophageal echocardiography (TEE): Evaluate for calcification, valve mobility, bicuspid anatomy, LV hypertrophy, EF, valvular gradients, aortic regurgitation

  • Cardiac catheterization: Coronary anatomy, cardiac output, transvalvular pressure gradients, LV function, coexisting valvular lesions

• • TEE: Evaluate for calcification, valve mobility, bicuspid anatomy, LV hypertrophy, EF, valvular gradients, aortic regurgitation

  • Cardiac catheterization: Coronary anatomy, cardiac output, transvalvular pressure gradients, LV function, coexisting valvular lesions

• • Mild AS: Aortic valve area > 1.5 cm2

  • Moderate AS: 1-1.5 cm2

  • Severe AS: ≤ 1 cm2

• • Balloon valvotomy: Limited role due to high restenosis rate within 6 mos; may be option if patient is decompensated with severe heart failure as a "bridge"

  • Valve replacement: Mechanical ...