Aortic Stenosis

By admin Last updated Nov 16, 2023

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Aortic Stenosis

Charles W. Webb

Ryan C. Petering

Basics

Description

Aortic stenosis is the most prevalent valvular heart disease. There are several terms that are used to describe different variants of aortic valve abnormalities.
- Aortic sclerosis: Calcification or thickening of the aortic valve without outflow obstruction
- Calcific aortic stenosis: Calcification on the aortic valve cusps that leads to outflow obstruction; most common etiology of aortic stenosis
- Congenital bicuspid aortic valve: Aortic stenosis resulting from 2-leaflet aortic valve with symptoms developing in 1st or 2nd decade of life; frequently associated with coarctation of the aorta
- Congenital aortic stenosis: Various valve structural abnormalities that lead to symptoms in childhood; less likely to be associated with heart failure and angina than adult onset aortic stenosis (1)
System(s) affected: Cardiovascular

Epidemiology

Incidence

Calcific aortic stenosis is frequency associated with age:
- Ages 65–74: 1–3% prevalence
- Ages 75–84: 2–4% prevalence
- Age >85: >4% prevalence
Predominant gender: Male > Female (slightly)
Bicuspid aortic valve present in 1–2% of newborns
Bicuspid aortic valve occurs predominantly in males (1).

Risk Factors

The exact mechanism of aortic stenosis is unclear.
Proposed mechanisms include lipid accumulation, inflammation, and calcification.
Risk factors include:
- Increasing age
- Male gender
- Hyperlipidemia
- Active inflammation (2)

Diagnosis

Classic triad of (1) dyspnea, (2) angina, and (3) syncope
Symptoms of heart failure (dyspnea on exertion, orthopnea, lower extremity edema)
Murmur: Harsh crescendo-decrescendo systolic murmur loudest over the right 2nd intercostal space with radiation toward the carotid artery
Parvus tardus: Slow, delayed carotid upstroke
Absent or diminished aortic component of 2nd heart sound (3)

Diagnostic Tests & Interpretation

Lab

There are no specific laboratory studies related to aortic stenosis.

Imaging

CXR and electrocardiogram frequently will be abnormal, but changes are not specific nor sensitive in the diagnosis of aortic stenosis.
Transthoracic echocardiogram (TTE):
- Mainstay for diagnosis and staging of aortic stenosis
- Key measurements include left ventricular systolic function, hypertrophy, transvalvular pressure gradient, and aortic valve area.
- Normal: Aortic jet velocity <2.5 m/s², aortic valve area 3–4 cm²
- Mild: Aortic jet velocity 2.5–2.9 m/s², aortic valve area 1.5–2 cm²
- Moderate: Aortic jet velocity 3–4 m/s², aortic valve area 1–1.5 cm²
- Severe: Aortic jet velocity >4 m/s², aortic valve area <1 cm² (3)

Diagnostic Procedures/Surgery

Cardiac catheterization is commonly performed as part of the diagnostic workup of aortic stenosis to rule out coexisting coronary artery disease (1).

Differential Diagnosis

Coronary artery disease
Congestive heart failure
Other valvular heart disease

Treatment

Some patients will present with hemodynamic instability that requires aggressive intervention.
Aortic valve replacement surgery is the only treatment for symptomatic aortic stenosis and is recommended for most symptomatic patients.
Nonurgent intervention is usually guided by patient symptoms.
Congestive heart failure symptoms (ie, shortness of breath, orthopnea, and dyspnea on exertion) are associated with increased mortality (4).
Close follow-up and observation is generally recommended for patients with aortic stenosis unless categorized as severe by TTE or symptoms exist.

P.35

Medication

No medications have been shown to influence the course or symptoms of aortic stenosis.
Coexisting hypertension, congestive heart failure, hyperlipidemia, and coronary artery disease should be treated according to individual guidelines (1).

Surgery/Other Procedures

Aortic valve replacement surgery is recommended for asymptomatic patients with severe aortic stenosis and left ventricular dysfunction (TTE finding of an ejection fraction of <50%) (4).

Ongoing Care

Activity recommendations need to be individualized owing to often complicated picture of coexisting conditions in aortic stenosis patients.
Asymptomatic, mild aortic stenosis: No restrictions in activity
Asymptomatic, moderate–severe aortic stenosis: Avoid competitive and vigorous activity with high dynamic and static muscle demands. Otherwise, exercise is generally permitted.
Symptomatic aortic stenosis: Activity contraindicated (1)

Follow-Up Recommendations

Patient Monitoring

TTE monitoring by aortic stenosis severity:
- Severe: Every 6–12 mos
- Moderate: Every 1–2 yrs
- Mild: Every 3–5 yrs
Treadmill stress testing can be used to help guide management of asymptomatic patients with moderate–severe aortic stenosis (3).

Patient Education

All asymptomatic patients who are being monitored need detailed education about the symptoms of heart failure.

Prognosis

1% annual risk of sudden death with asymptomatic aortic stenosis
Average overall survival rate for symptomatic patients is 2–3 yrs without aortic valve replacement.
Aortic valve replacement surgery perioperative overall mortality is roughly 4%. There is great variability in risk based on patient age and coexisting conditions.
- Patients without coexisting conditions and age 55–65 yrs: 1% risk
- Patients with coexisting hypertension and coronary artery disease and age 85 yrs: 7% risk
- Patients with coexisting hypertension, coronary artery disease, and previous cardiac catheterization and age 85 yrs: 24% risk (4)

References

1. Carabellow BA, Paulus WJ. Aortic stenosis. The Lancet. 2009;373:956–966.

2. Dal-Bianco JP, et al. Management of severe asymptomatic aortic stenosis. J Am Coll Cardiol. 2008;52:1279–1292.

3. Gimard BH, Larson JM. Aortic stenosis: diagnosis and treatment. Am Fam Physician. 2008;78(6):717–725.

4. Otto CM. Valvular aortic stenosis. J Am Coll Cardiol. 2006;47:2141–2151.

Codes

ICD9

424.1 Aortic valve disorders
440.0 Atherosclerosis of aorta
746.4 Congenital insufficiency of aortic valve