Aortic Stenosis Disease

BASICS

DESCRIPTION

An acquired or congenital obstruction to systolic left ventricular outflow across the aortic valve

System(s) affected: Cardiovascular
Genetics: N/A
Incidence/Prevalence in USA:
- Except for mitral regurgitation due to myocardial disease, valvular aortic stenosis is the most common fatal cardiac valve lesion
- Bicuspid aortic valve has a frequency of 400 per 100,000 live births
Predominant age:
- Age < 30 years - predominantly congenital
- Age 30 to 70 years - most commonly congenital or rheumatic
- Age > 70 years - most commonly degenerative calcification of the aortic valve
Predominant sex:
- Congenital bicuspid valves: Male > Female (4:1)
- Congenital unicuspid valves: Male > Female (3:1)

SIGNS AND SYMPTOMS

Angina pectoris (most frequent symptom, occurring in 50-70% of patients with severe aortic stenosis)
Near syncope
Syncope (often exertional, occurs in 15-30% of patients with severe aortic stenosis)
Exertional dyspnea
Orthopnea
Paroxysmal nocturnal dyspnea
Palpitations
Fatigue
Neurologic events (transient ischemic attack or cerebrovascular accident) due to embolization
Systolic crescendo-decrescendo murmur, usually best heard at the second right sternal border (may have associated thrill) and may radiate into the carotid arteries
Ejection (early systolic) click
Prolonged ejection time
Delayed, small carotid upstroke
Delayed/decreased intensity of A2
Paradoxical splitting of S2
Left ventricular heave
A high pitched diastolic blow may be present at the left sternal border (associated aortic regurgitation)

CAUSES

Congenital etiologies
- Unicuspid valve
- Bicuspid valve (not inherently stenotic, but becomes so as a result of 'wear and tear' thickening and calcification; a calcified bicuspid valve is the most common cause of isolated aortic stenosis in adults)
- Three cusped valve with fusion of commissures
- Hypoplastic annulus
Acquired etiologies
- Rheumatic (or, rarely, other inflammatory disease)
- Degenerative calcific aortic stenosis in the elderly

RISK FACTORS

History of rheumatic fever

DIAGNOSIS

LABORATORY

N/A

Drugs that may alter lab results: N/A
Disorders that may alter lab results: N/A

PATHOLOGICAL FINDINGS

Left ventricular hypertrophy
Myocardial interstitial fibrosis
Aortic valvular calcification in older patients
50% incidence of concomitant coronary artery disease

SPECIAL TESTS

ECG: Left ventricular hypertrophy, often with associated ST segment depression, conduction defects, left atrial enlargement, ventricular arrhythmias

IMAGING

Chest x-ray
- May be normal in compensated, isolated valvular aortic stenosis
- Cardiac hypertrophy early, later cardiomegaly
- Post stenotic dilatation of the ascending aorta
- Calcification of aortic valve cusps (may require fluoroscopy to visualize)

DIAGNOSTIC PROCEDURES

Echocardiography:
- Aortic valve morphology, thickening, calcifications
- Decreased aortic valve excursion
- Planimetry of aortic valve area
- Left ventricular hypertrophy
- Chamber dimensions
- Presence or absence of wall motion abnormalities suggestive of coronary artery disease
With Doppler echocardiography:
- Transvalvular gradient
- Valve area
- Diastolic function
- Associated aortic regurgitation
Cardiac catheterization:
- Transvalvular gradient
- Valve area
- Left ventricle ejection fraction
- Concomitant coronary artery disease

TREATMENT

APPROPRIATE HEALTH CARE

Outpatient except for surgical intervention

GENERAL MEASURES

Aortic stenosis is a progressive disease. The asymptomatic patient with non-critical aortic stenosis can be closely followed with appropriate evaluation.
All patients with valvular aortic stenosis should receive endocarditis prophylaxis, prior to dental work or invasive procedures regardless of age, etiology or severity of the stenosis (as recommended by the American Heart Association in Circulation, 1997; 96: 358-366)
Patients with a rheumatic etiology should receive (in addition to endocarditis prophylaxis prior to dental work or invasive procedures) rheumatic fever prophylaxis, especially if less than 35 years of age, or continue to be in close contact with young children

SURGICAL MEASURES

Prompt aortic valve replacement is clearly indicated in patients with symptomatic severe aortic stenosis
Consider aortic valve replacement in asymptomatic patients with critical aortic stenosis (aortic valve area < 1.0 cm2 or gradient > 50 mm Hg [> 6.6 kPa]) particularly if there is left ventricular dysfunction, increasing cardiomegaly, and clinical symptoms
Surgical valve replacement consists of the removal of the stenotic, native valve and placement of a prosthetic mechanical or tissue valve
Balloon angioplasty of stenotic aortic valves may be of benefit in the pediatric patient with congenital disease. Also feasible (although one must expect suboptimal results) in the elderly, debilitated patient who may not tolerate valve replacement.

ACTIVITY

In known or suspected severe aortic stenosis, vigorous physical activity is contraindicated

DIET

No restrictions except sodium restriction in presence of congestive heart failure

PATIENT EDUCATION

Educate the patient about the symptoms of symptomatic aortic stenosis and to report these promptly should they occur
If moderate or severe aortic stenosis is known or suspected, instruct the patient to avoid vigorous physical activity
Instruct the patient when prophylactic antibiotics are needed for medical or dental procedures

FOLLOW UP

PREVENTION/AVOIDANCE

Bacterial endocarditis prophylaxis
Rheumatic fever prophylaxis, where indicated
Avoidance of vigorous physical activity

POSSIBLE COMPLICATIONS

Progressive stenosis
Sudden death
Congestive heart failure
Angina
Syncope
Hemolytic anemia
Infective endocarditis

EXPECTED COURSE AND PROGNOSIS

Mean life expectancy without intervention in patients with aortic stenosis is 5 years after the onset of exertional chest discomfort, 3 years after the onset of syncope, 2 years after the development of heart failure
Sudden death occurs in 15 to 20% of patients with symptomatic aortic stenosis

MISCELLANEOUS

ASSOCIATED CONDITIONS

Coronary artery disease is present in 50% of patients with aortic stenosis
Aortic regurgitation (particularly seen in calcified bicuspid valves and rheumatic disease)
Mitral valve disease (primarily in rheumatic heart disease)

AGE-RELATED FACTORS

Pediatric: N/A
Geriatric: Increased incidence of degenerative calcific aortic stenosis
Others: N/A

PREGNANCY

Severe critical aortic stenosis tolerates poorly the hemodynamic changes in pregnancy, labor and delivery. Pregnancy should be avoided with critical aortic stenosis.

OTHER NOTES

As the left ventricle is relatively noncompliant in aortic stenosis, atrial contraction is an important component of diastolic filling. The loss of this component with the onset of atrial fibrillation can cause acute clinical and hemodynamic deterioration.

ABBREVIATIONS

N/A

Clinical Investigations

ROLE OF HOMOEOPATHY

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