Aortic valve stenosis (AS) is a valvular heart disease characterized by narrowing of the aortic valve. As a result, the outflow of blood from the left ventricle into the aorta is obstructed. This leads to chronic and progressive excess load on the left ventricle and potentially left ventricular failure. The patient may remain asymptomatic for long periods of time; for this reason, AS is often detected late when it first becomes symptomatic (dyspnea on exertion, angina pectoris, or syncope). Auscultation reveals a harsh, crescendo-decrescendo murmur in systole that radiates to the carotids, and pulses are delayed with diminished carotid upstrokes. Echocardiography is the noninvasive gold standard for diagnosis. Patients with mild asymptomatic aortic stenosis are treated conservatively with monitoring and medical management of related conditions (e.g., hypertension). Symptomatic patients, or those with severe aortic valve stenosis, require immediate aortic valve replacement (AVR) as definitive treatment. Options for valve replacement include surgical AVR or transcatheter AVR (TAVR) for patients with high operative risk. Patients with severe AS have a high risk of developing acute complications such as heart failure and cardiogenic shock, which are challenging to manage and often require critical care interventions and expedited surgery or TAVR.
The most common etiologies of valvular aortic stenosis include:
- Aortic valve sclerosis: calcification and fibrosis of aortic valve leaflets 
Bicuspid aortic valve (BAV): fusion of two of the three aortic-valve leaflets in utero 
- Most common congenital heart valve malformation , predominantly affects males (3:1) 
- Predisposes the valve to and degeneration
- Patients present with symptoms of aortic stenosis earlier than in regular aortic valve calcification. 
- Congenital aortic stenosis is rare and usually features a unicuspid or bicuspid valve. 
occurs without aortic stenosis in its early stages, but can progress to aortic stenosis once signs of begin to occur. 
- Narrowed opening area of the aortic valve during systole → obstruction of blood flow from left ventricle (LV) → increased LV pressure → left ventricular concentric hypertrophy, which leads to:
- Initially, cardiac output (CO) can be maintained (see “Compensation mechanisms” in “ ”)
- Later, the decreased distensibility of the left ventricle reduces cardiac output and may then cause backflow into the pulmonary veins and capillaries → higher afterload (pulmonic pressure) on the right heart → right heart failure
Aortic stenosis may remain asymptomatic for years, particularly with mild or moderate stenosis. Symptoms usually start to develop when the disease progresses to severe AS, and may present at rest or on exertion.
- Signs and symptoms
- Physical examination
- Harsh crescendo-decrescendo (diamond-shaped), late systolic ejection murmur that radiates bilaterally to the carotids
- Soft S2
- S4 is best heard at the apex.
- Early systolic ejection click
American Heart Association (AHA)/American College of Cardiology (ACC) staging system 
- Used to monitor disease progression and determine the need for intervention
- Based on echocardiographic criteria of valve anatomy and hemodynamics
- Aortic valve area (AVA): the opening area of the aortic valve measured during systole and an important factor in the evaluation of severity of aortic valve stenosis
- Transaortic velocity: the maximum velocity of blood flow measured across the aortic valve during systole; inversely related to the aortic valve area
Mean aortic pressure gradient: the difference in pressure between the left ventricle and the ascending aorta during systole
- Pressures normally equilibrate relatively rapidly when the valve opens.
- Valvular stenosis limits the increase in aortic pressure while increasing the LV pressure, leading to a higher gradient.
- The term critical aortic stenosis is commonly used to describe severe AS and/or decompensated AS, however, there is a lack of consensus on the defining parameters. 
|AHA/ACC staging for aortic valve stenosis |
|Severity||Definition||AVA||Transaortic velocity||Mean aortic pressure gradient|
|Mild-to-moderate aortic stenosis||Stage A aortic valve stenosis||At risk of AS||3–4 cm2||< 2.0 m/second||< 10 mm Hg|
|Stage B aortic valve stenosis||Progressive AS||Mild: 1.5–2.9 cm2||2.0– 2.9 m/second||10–19 mm Hg|
|Moderate: 1.0–1.4 cm2||3.0–3.9 m/second||20–39 mm Hg|
|Severe aortic stenosis||Stage C1 aortic valve stenosis||Asymptomatic severe AS (LVEF normal)||≤ 1.0 cm2||≥ 4.0 m/second||≥ 40 mm Hg|
|Stage C2 aortic valve stenosis|
|Stage D aortic valve stenosis||Symptomatic severe AS|
- Indication: assessment of aortic valve structure, function, and stenosis severity, left ventricle and other heart valves (see “ ”)
- Supportive findings
- Laboratory studies: usually nonspecific and therefore not routinely indicated; however, they can be useful for the evaluation of other possible etiologies.
- ECG 
- Chest x-ray: Used to assess for pulmonary edema or other causes of dyspnea. 
Additional evaluation 
- Indication: stage D AS with LVEF < 50% to determine the true anatomic severity of the stenosis
- Typical findings (in response to dobutamine)
- Indication: stage C1 AS and stage C2 AS to assess physiological changes with exercise
- Findings: exertional symptoms, e.g., angina, excessive dyspnea, dizziness, or syncope
- Interpretation: Exertional findings indicate stage D AS.
Diagnostic cardiac catheterization: an accurate diagnostic test for the evaluation of aortic valve area, cardiac output, and mean aortic pressure gradient (not routinely indicated) 
- Consider in symptomatic patients with inconclusive noninvasive testing or discrepancy between symptoms and noninvasive testing. 
- Findings: similar to echocardiographic findings
- Coronary angiography
- Complications: See “Complications” in cardiac catheterization.
Advanced imaging 
Consider the following noninvasive imaging options in the perioperative assessment of patients with severe AS, along with expert consultation.
- Cardiac CT
- Cardiac MRI
- See “ ” for an overview of other valvulopathies.
- See “ ” and “ .”
- See “ .”
- See “ .”
- Symptomatic and/or : or repair is usually indicated.
- Asymptomatic or : usually ; consider early in select patients. 
- Provide supportive care: e.g., manage comorbidities (e.g., hypertension, diabetes), monitor progression with serial echocardiography, provide for at-risk patients.
- Manage acute heart failure) with individualized critical care focusing on acute stabilization and expedited surgical treatment. (e.g.,
- Consult cardiology and/or cardiothoracic surgery.
Managing comorbidities 
- Hypertension: Follow standard hypertension guidelines; medication should be carefully titrated to avoid hypotension. See “Hypertension management.”
- Diabetes mellitus: See “Diabetes management.” 
Echocardiographic monitoring 
- Regular follow-up imaging is indicated for asymptomatic patients with:
- On-demand imaging is indicated for patients with:
- Any change in signs or symptoms
- Conditions that have high hemodynamic/metabolic demands
Prophylactic antibiotics 
- Rheumatic heart disease: Patients should receive secondary prophylaxis, e.g., penicillin G benzathine or sulfadiazine (see “Prevention” in “ ” for more details). 
- Dental procedures: Consider aortic valve replacement). for at-risk patients (e.g., after
- Nondental procedures (e.g., EGD, TEE, colonoscopy): Antibiotic prophylaxis is not recommended.
Aortic valve replacement (AVR) and repair 
- Symptomatic patients with severe, high-gradient AS (stage D AS)
- Asymptomatic patients with severe AS and:
- AVR can also be beneficial for certain patients with moderate (stage B AS) to severe (stage D AS) with specific characteristics.
Surgical AVR (SAVR) is recommended for patients with:
- Age < 65 years
- Life expectancy > 20 years
- Low to moderate surgical risk
- Transcatheter AVR (TAVR)
- Percutaneous balloon valvuloplasty 
Complications of aortic valve replacement 
- Vascular complications, thromboembolism/stroke
- Major bleeding
- Renal failure
- Arrhythmias: atrioventricular block, atrial fibrillation
- Aortic regurgitation/paravalvular leak
- Infection: endocarditis
|Antithrombotic therapy for patients with prosthetic aortic valves |
|Choice of agent||Target INR||Duration of therapy|
|Mechanical valve and no risk factors for|| || |
OR older generation mechanical valves
Bioprosthetic valve with low risk of bleeding
Critical complications of AS
The following can rapidly lead to decompensation and circulatory collapse in patients with severe AS:
Focus on acute stabilization while expediting definitive surgical treatment.
- Consult cardiology and cardiothoracic surgery immediately.
- Tailor stabilization to the physiological constraints of (e.g., fixed , ); see “ ” for details.
- For details on the standard management of each complication, see:
- “ ”
- “ ”
- “ ”
Hemodynamic stabilization in severe AS 
Manage hemodynamically unstable patients with in consultation with a specialist while awaiting definitive surgical treatment.
- General principles
- Hypervolemia: Use diuretics with caution.
- Flash pulmonary edema: Use nitrates and with caution.
- Hypovolemia: Consider judicious while regularly reassessing .
- Persistent hypotension
- : Consider dobutamine to increase heart rate and contractility without increasing afterload.
- is preferred in most cases.
- Use medications and other with caution.
We list the most important complications. The selection is not exhaustive.
The following applies to unstable patients with aortic stenosis:
- Perform ABCDE assessment.
- Start continuous cardiac monitoring and pulse oximetry.
- If unclear, confirm the diagnosis and TTE. with bedside
- Identify and treat .
- Consult cardiology and cardiothoracic surgery for definitive management.
- If necessary, begin under specialist guidance while awaiting definitive treatment.
- Initiate emergency preoperative evaluation.
- Transfer to OR or ICU.