Aortic Stenosis

KEY FEATURES

Essentials of Diagnosis

• Congenital bicuspid aortic valve, usually asymptomatic until middle or old age

• "Degenerative" or calcific aortic stenosis; similar risk factors as atherosclerosis

• Visual observation of immobile aortic valve plus a valve area of < 1.0 cm² define severe disease

• Echocardiography/Doppler is diagnostic

• Surgery typically indicated for symptoms; transcatheter aortic valve replacement (TAVR) approved for calcific aortic stenosis

• Intervention appropriate even in asymptomatic patients with mean gradient > 55 mm Hg or when undergoing heart surgery for other reasons

• High B-type natriuretic peptide (BNP) levels (three times normal) can be an indication for intervention

General Considerations

• There are two common clinical scenarios in which aortic stenosis is prevalent

  • Congenitally abnormal unicuspid or bicuspid valve, rather than tricuspid

    • Symptoms can occur in young or adolescent individuals if the stenosis is severe but more often emerge at age 50–65 years

    • A dilated ascending aorta may accompany the bicuspid valve

    • Coarctation of the aorta is seen in patients with congenital aortic stenosis

    • Offspring of patients with a bicuspid valve have a much higher incidence of the disease in either the valve, the aorta, or both

  • Degenerative or calcific aortic stenosis

    • May be related to calcium deposition as occurs in atherosclerotic vascular disease

    • Approximately 25% of patients over age 65 years and 35% of those over age 70 years have echocardiographic evidence of aortic valve thickening

    • Hemodynamically significant aortic stenosis will develop in about 10–20% of these patients over 10–15 years

    • A genetic component appears a likely contributor

• Risk factors include

  • Hypertension

  • Hypercholesterolemia

  • Smoking

• Aortic stenosis has become the most common surgical valve lesion in developed countries

• Many patients are older adults

• Hypertrophic obstructive cardiomyopathy may coexist with valvular aortic stenosis

CLINICAL FINDINGS

Symptoms and Signs

Mild to moderate aortic stenosis

• Slightly narrowed, thickened, or roughened valves (aortic sclerosis) or aortic dilation may contribute to the typical ejection murmur of aortic stenosis

• When the valve is still pliable, an ejection click may precede the murmur and the closure of the valve (S₂) is preserved

• The characteristic systolic ejection murmur is heard at the aortic area and is usually transmitted to the neck and apex

• In some cases, only the high-pitched components of the murmur are heard at the apex, and the murmur may sound like mitral regurgitation (so-called Gallaverdin phenomenon)

Severe aortic stenosis

• Left ventricular (LV) failure, angina pectoris, or syncope

  • May be presenting symptoms

  • Tend to first occur with exertion

• A palpable LV heave or thrill, a weak to absent aortic second sound, or reversed splitting of the second sound

• Prolonged ventricular systole and typical carotid pulse pattern of delayed upstroke and low amplitude

  • Present when the valve ...