Aortic Stenosis

Practice Essentials

Aortic stenosis is the obstruction of blood flow across the aortic valve (see the image below). Among symptomatic patients with medically treated moderate-to-severe aortic stenosis, mortality from the onset of symptoms is approximately 25% at 1 year and 50% at 2 years. Symptoms of aortic stenosis usually develop gradually after an asymptomatic latent period of 10-20 years.

View Image

Stenotic aortic valve (macroscopic appearance).

Signs and symptoms

The classic triad of symptoms in patients with aortic stenosis is as follows^[1] :

• Chest pain: Angina pectoris in patients with aortic stenosis is typically precipitated by exertion and relieved by rest.
• Heart failure: Symptoms include paroxysmal nocturnal dyspnea, orthopnea, dyspnea on exertion, and shortness of breath.
• Syncope: This often occurs upon exertion when systemic vasodilatation in the presence of a fixed forward stroke volume causes the arterial systolic blood pressure to decline.

Systolic hypertension can coexist with aortic stenosis. However, a systolic blood pressure higher than 200 mmHg is rare in patients with critical aortic stenosis.

In severe aortic stenosis, the carotid arterial pulse typically has a delayed and plateaued peak, decreased amplitude, and gradual downslope (pulsus parvus et tardus).

Other symptoms of aortic stenosis include the following:

• Pulsus alternans: Can occur in the presence of left ventricular systolic dysfunction
• Hyperdynamic left ventricle: Unusual; suggests concomitant aortic regurgitation or mitral regurgitation
• Soft or normal S1
• Diminished or absent A2: The presence of a normal or accentuated A2 speaks against the existence of severe aortic stenosis
• Paradoxical splitting of the S2: Resulting from late closure of the aortic valve with delayed A2
• Accentuated P2: In the presence of secondary pulmonary hypertension
• Ejection click: Common in children and young adults with congenital aortic stenosis and mobile valve leaflets
• Prominent S4: Resulting from forceful atrial contraction into a hypertrophied left ventricle
• Systolic murmur: The classic crescendo-decrescendo systolic murmur of aortic stenosis begins shortly after the first heart sound; the intensity increases toward mid systole and then decreases, with the murmur ending just before the second heart sound

See Presentation for more detail.

Diagnosis

The following studies are used in the diagnosis and assessment of aortic stenosis:

• Serum electrolyte levels
• Cardiac biomarkers
• Complete blood count
• B-type natriuretic peptide: May provide incremental prognostic information for predicting symptom onset in asymptomatic patients with severe aortic stenosis^[2] ; increased levels appear to be associated with aortic stenosis-related adverse events in asymptomatic severe aortic stenosis^[3]
• Electrocardiography (ECG): Serial ECG can demonstrate the progression of aortic stenosis
• Chest radiography
• Echocardiography: Two-dimensional and Doppler
• Cardiac catheterization: Can be used if clinical findings are inconsistent with echocardiogram results
• Coronary angiography
• Radionuclide ventriculography: May provide information on left ventricular function
• Exercise stress testing: Contraindicated in symptomatic patients with severe aortic stenosis

See Workup for more detail.

Management

The only definitive treatment for aortic stenosis in adults is aortic valve replacement (surgical or percutaneous). The development of symptoms due to this condition provides a clear indication for replacement.^{[4, 5]}  Infants, children, and adolescents with a bicuspid valve may undergo balloon or surgical valvotomy. 

Emergency care

A patient presenting with uncontrolled heart failure should be treated supportively with oxygen, cardiac and oximetry monitoring, intravenous access, loop diuretics, nitrates (keep in mind the potential nitrate sensitivity of patients with aortic stenosis), morphine (as needed and tolerated), and noninvasive or invasive ventilatory support (as indicated). Patients with severe heart failure due to aortic stenosis that is resistant to medical management should be considered for urgent surgery.

Pharmacologic therapy

Agents used in the treatment of patients with aortic stenosis include the following:

• Digitalis, diuretics, and angiotensin-converting enzyme (ACE) inhibitors: Can be cautiously used in patients with pulmonary congestion
• Vasodilators: May be used to treat for heart failure and for hypertension but should also be employed with extreme caution
• Digoxin, diuretics, ACE inhibitors, or angiotensin receptor blockers^[5] : Recommended by the European Society of Cardiology (ESC)/European Association for Cardio-Thoracic Surgery (EACTS) guidelines for patients with heart failure symptoms who are not suitable candidates for surgery or transcatheter aortic valve implantation

Aortic valve replacement

According to American College of Cardiology (ACC)/American Heart Association (AHA) guidelines, candidates for aortic valve replacement include the following patients^[6] :

• Symptomatic patients with severe aortic stenosis
• Patients with asymptomatic, severe aortic stenosis undergoing coronary artery bypass surgery
• Patients with asymptomatic, severe aortic stenosis undergoing surgery on the aorta or other heart valves
• Patients with asymptomatic, severe aortic stenosis and left ventricular systolic dysfunction (ejection fraction < 0.50)

Percutaneous balloon valvuloplasty

Percutaneous balloon valvuloplasty is used as a palliative measure in critically ill adult patients who are not surgical candidates or as a bridge to aortic valve replacement in critically ill patients.

See Treatment and Medication for more detail.

• References

Background

Aortic stenosis is the obstruction of blood flow across the aortic valve. Aortic stenosis has several etiologies, including congenital (unicuspid or bicuspid valve), calcific (due to degenerative changes), and rheumatic. Degenerative calcific aortic stenosis is now the leading indication for aortic valve replacement. The favorable long-term outcome following aortic valve surgery and the relatively low operative risk emphasize the importance of an accurate and timely diagnosis (see Prognosis).

A stenotic valve is shown in the image above. Symptoms of aortic stenosis usually develop gradually after an asymptomatic latent period of 10-20 years. Exertional dyspnea or fatigue is the most common initial complaint. Ultimately, most patients experience the classic triad of chest pain, heart failure, and syncope (see History).

Two-dimensional (2D) Doppler echocardiography is the imaging modality of choice to diagnose and estimate the severity of aortic stenosis and localize the level of obstruction (see Workup). The only definitive treatment for aortic stenosis is aortic valve replacement, either surgically or percutaneously. (see Treatment).

Go to Pediatric Valvar Aortic Stenosis, Pediatric Subvalvar Aortic Stenosis, and Pediatric Supravalvar Aortic Stenosis for more complete information on these topics.

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Pathophysiology

When the aortic valve becomes stenotic, resistance to systolic ejection occurs and a systolic pressure gradient develops between the left ventricle and the aorta. This outflow obstruction leads to an increase in left ventricular (LV) systolic pressure. As a compensatory mechanism to normalize LV wall stress, LV wall thickness increases by parallel replication of sarcomeres, producing concentric hypertrophy. At this stage, the chamber is not dilated and ventricular function is preserved, although diastolic compliance is reduced.

Eventually, however, LV end-diastolic pressure (LVEDP) rises, which causes a corresponding increase in pulmonary capillary arterial pressures and a decrease in cardiac output due to diastolic dysfunction. The contractility of the myocardium may also diminish, which leads to a decrease in cardiac output due to systolic dysfunction. Ultimately, heart failure develops.

In most patients with aortic stenosis, LV systolic function is preserved and cardiac output is maintained for many years despite an elevated LV systolic pressure. Although cardiac output is normal at rest, it often fails to increase appropriately during exercise, which may result in exercise-induced symptoms.

Diastolic dysfunction may occur as a consequence of impaired LV relaxation and/or decreased LV compliance, as a result of increased afterload, LV hypertrophy, or myocardial ischemia. LV hypertrophy often regresses following relief of valvular obstruction. However, some individuals develop extensive myocardial fibrosis, which may not resolve despite regression of hypertrophy.

In patients with severe aortic stenosis, atrial contraction plays a particularly important role in diastolic filling of the LV. Thus, development of atrial fibrillation in aortic stenosis often leads to heart failure due to an inability to maintain cardiac output.

Increased LV mass, increased LV systolic pressure, and prolongation of the systolic ejection phase all elevate the myocardial oxygen requirement, especially in the subendocardial region. Although coronary blood flow may be normal when corrected for LV mass, coronary flow reserve is often reduced.

Myocardial perfusion is thus compromised by the relative decline in myocardial capillary density and by a reduced diastolic transmyocardial (coronary) perfusion gradient due to elevated LV diastolic pressure. Therefore, the subendocardium is susceptible to underperfusion, which results in myocardial ischemia.

Angina results from a concomitant increased oxygen requirement by the hypertrophic myocardium and diminished oxygen delivery secondary to diminished coronary flow reserve, decreased diastolic perfusion pressure, and relative subendocardial myocardial ischemia.

There may exist a causal association between LDL-C-related genetic variants and aortic valve disease. In a community-based study consisting of 6942 subjects with data on aortic valve calcium and more than 28,000 subjects with aortic stenosis (follow-up, >16 y), Smith et al found that genetic predisposition toward elevations in low-density lipoprotein cholesterol (LDL-C) (as indicated by genetic risk scores [GRSs])—but not elevated high-density lipoprotein cholesterol (HDL-C) or triglycerides GRSs—were associated with the presence of aortic valve calcium and the incidence of aortic stenosis.^[7]  Whether early intervention aimed at reducing LDL-C levels may help to prevent aortic valve disease is unknown.

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Etiology

Most cases of aortic stenosis are due to the obstruction at the valvular level. Common causes are summarized in Table 1.

Table 1. Common Causes of Aortic Stenosis Among Patients Requiring Surgery

View Table

See Table

Valvular aortic stenosis can be either congenital or acquired.

Congenital valvular aortic stenosis

Congenitally unicuspid, bicuspid, tricuspid, or even quadricuspid valves may cause aortic stenosis. In neonates and infants younger than 1 year, a unicuspid valve can produce severe obstruction and is the most common anomaly in infants with fatal valvular aortic stenosis. In patients younger than 15 years, unicuspid valves are most frequent in cases of symptomatic aortic stenosis.

In adults who develop symptoms from congenital aortic stenosis, the problem is usually a bicuspid valve. Bicuspid valves do not cause significant narrowing of the aortic orifice during childhood. The altered architecture of the bicuspid aortic valve induces turbulent flow with continuous trauma to the leaflets, ultimately resulting in fibrosis, increased rigidity and calcification of the leaflets, and narrowing of the aortic orifice in adulthood.

A cohort study by Tzemos et al of 642 ambulatory adults with bicuspid aortic valves found that during the mean follow-up duration of 9 years, survival rates were not lower than for the general population. However, young adults with bicuspid aortic valve had a high likelihood of eventually requiring aortic valve intervention.^[8]

Congenitally malformed tricuspid aortic valves with unequally sized cusps and commissural fusion (“functionally bicuspid” valves) can also cause turbulent flow leading to fibrosis and, ultimately, to calcification and stenosis. Clinical manifestations of congenital aortic stenosis in adults usually appear after the fourth decade of life.

Acquired valvular aortic stenosis

The main causes of acquired aortic stenosis include degenerative calcification and, less commonly, rheumatic heart disease.

Degenerative calcific aortic stenosis (also called senile calcific aortic stenosis) involves progressive calcification of the leaflet bodies, resulting in limitation of the normal cusp opening during systole. This represents a consequence of long-standing hemodynamic stress on the valve and is currently the most frequent cause of aortic stenosis requiring aortic valve replacement. The calcification may also involve the mitral annulus or extend into the conduction system, resulting in atrioventricular or intraventricular conduction defects.

Risk factors for degenerative calcific aortic stenosis include advanced age, hypertension, hypercholesterolemia, diabetes mellitus, and smoking. The available data suggest that the development and progression of the disease are due to an active disease process at the cellular and molecular level that shows many similarities with atherosclerosis, ranging from endothelial dysfunction to, ultimately, calcification.^[9]

In rheumatic aortic stenosis, the underlying process includes progressive fibrosis of the valve leaflets with varying degrees of commissural fusion, often with retraction of the leaflet edges and, in certain cases, calcification. As a consequence, the rheumatic valve often is regurgitant and stenotic. Coexistent mitral valve disease is common.

Other, infrequent causes of aortic stenosis include obstructive vegetations, homozygous type II hypercholesterolemia, Paget disease, Fabry disease, ochronosis, and irradiation.

It is worthwhile to note that although differentiation between tricuspid and bicuspid aortic stenosis is frequently made, it is often difficult to determine the number of aortic valve leaflets. A study comparing operatively excised aortic valve structure evaluation by cardiac surgeons versus pathologists found that valve structure determination was frequently incongruous.^[10]

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Epidemiology

Severe aortic stenosis is rare in infancy, occurring in 0.33% of live births, and is due to a unicuspid or bicuspid valve. Most patients with a congenitally bicuspid aortic valve who develop symptoms do not do so until middle age or later. Patients with rheumatic aortic stenosis typically present with symptoms after the sixth decade of life.

Aortic sclerosis (aortic valve calcification without obstruction to blood flow, considered a precursor of calcific degenerative calcific aortic stenosis) increases in incidence with age and is present in 29% of individuals older than 65 years and in 37% of individuals older than 75 years. In elderly persons, the prevalence of aortic stenosis is between 2% and 9%.

Degenerative calcific aortic stenosis usually manifests in individuals older than 75 years and occurs most frequently in males.^[4]

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Prognosis

Patients with severe aortic stenosis may be asymptomatic for many years despite the presence of severe LV outflow tract obstruction (LVOTO). LVOTOs have been associated with “high heritability.” One study suggests that 20% of patients with isolated LVOTO had an affected first-degree relative with undetected bicuspid aortic valves.^[11]

Asymptomatic patients, even with critical aortic stenosis, have an excellent prognosis for survival, with an expected death rate of less than 1% per year; only 4% of sudden cardiac deaths in severe aortic stenosis occur in asymptomatic patients. A new proposed aortic stenosis grading classification that integrates valve area and flow-gradient patterns has been found to allow for better characterization of the clinical outcome among patients with asymptomatic severe aortic stenosis.^[12]

In general, the presence of low-gradient "severe stenosis" (defined as aortic valve area < 1.0 cm² and mean gradient 40 mmHg), representing up to 40% of all patients with aortic stenosis, is considered to be associated with a poor prognosis.^[13] However, the prospective Simvastatin and Ezetimibe in Aortic Stenosis (SEAS) study found that such patients have an outcome similar to that of patients with moderate stenosis.^[14]  A more recent study found that symptomatic paradoxical low-gradient severe aortic stenosis is associated with a poorer prognosis even after adjustment for flow status and aortic stenosis severity.^[15] Moreover, the investigators indicated there may be a possible link to heart failure with preserved ejection fraction in some symptomatic patients.^[15]

Among symptomatic patients with medically treated, moderate-to-severe aortic stenosis, mortality rates from the onset of symptoms are approximately 25% at 1 year and 50% at 2 years. More than 50% of deaths are sudden. In patients in whom the aortic valve obstruction remains unrelieved, the onset of symptoms predicts a poor outcome with medical therapy; the approximate time interval from the onset of symptoms to death is 1.5-2 years for heart failure, 3 years for syncope, and 5 years for angina.

Although the obstruction tends to progress more rapidly in degenerative calcific aortic valve disease than in congenital or rheumatic disease, predicting the rate of progression in individual patients is not possible. Catheterization and echocardiographic studies suggest that, on average, the valve area declines 0.1 to 0.3 cm² per year; the systolic pressure gradient across the valve can increase by as much as 10-15 mmHg per year. Obstruction progresses more rapidly in elderly patients with coronary artery disease and chronic renal insufficiency.

Epicardial adipose tissue (EAT) volume appears to be associated with adverse outcomes in patients with severe aortic stenosis undergoing transcatheter aortic valve replacement (TAVR). A retrospective study of 503 such patients found EAT volume was independently associated with all-cause 1-, 2-, and 3-year mortality and the early safety endpoint at 30 days.^[16]

Complications

Possible complications of aortic stenosis include the following:

• Sudden cardiac death
• Heart failure
• Conduction defects
• Calcific embolization

• References

History

Aortic stenosis usually has an asymptomatic latent period of 10-20 years. During this time, the LV outflow obstruction and the pressure load on the myocardium gradually increase. Symptoms develop gradually. Exertional dyspnea is the most common initial complaint, even in patients with normal LV systolic function, and it often relates to abnormal LV diastolic function. In addition, patients may develop exertional chest pain, effort dizziness or lightheadedness, easy fatigability, and progressive inability to exercise. Ultimately, patients experience one of the classic triad of chest pain, heart failure, and syncope.^[1]

Chest pain

Angina pectoris in patients with aortic stenosis is typically precipitated by exertion and relieved by rest. Thus, it may resemble angina from coronary artery disease.

Heart failure

Heart failure symptoms (ie, paroxysmal nocturnal dyspnea, orthopnea, dyspnea on exertion, and shortness of breath) may be due to systolic dysfunction from afterload mismatch, ischemia, or a separate cardiomyopathic process. Alternatively, diastolic dysfunction from LV hypertrophy or ischemia may also result in heart failure symptoms.

Results from the Simvastatin Ezetimibe in Aortic Stenosis (SEAS) study revealed that in patients with aortic stenosis without diabetes or known renal or cardiovascular disease, persistent or new-onset asymmetric interventricular septum hypertrophy was associated with a higher incidence of ischemic cardiovascular events than in those without asymmetric interventricular septum hypertrophy.^[17]

Syncope

Syncope from aortic stenosis often occurs upon exertion when systemic vasodilatation in the presence of a fixed forward stroke volume causes the arterial systolic blood pressure to decline. It also may be caused by atrial or ventricular tachyarrhythmias.

Syncope at rest may be due to transient ventricular tachycardia, atrial fibrillation, or (if calcification of the valve extends into the conduction system) atrioventricular block. Another cause of syncope is abnormal vasodepressor reflexes due to increased LV intracavitary pressure (vasodepressor syncope).

Syncope may be accompanied by convulsions.^[18]

Patients with aortic stenosis may have a higher incidence of nitroglycerin-induced syncope than does the general population. Always consider aortic stenosis as a possible etiology for a patient who demonstrates particular hemodynamic sensitivity to nitrates.

Other manifestations

Gastrointestinal bleeding due to angiodysplasia (ie, Heyde syndrome^[19] ) or other vascular malformations is present at a higher than expected frequency in patients with calcific aortic stenosis. These malformations usually resolve following aortic valve surgery.

Patients may present with manifestations of infective endocarditis (ie, fever, fatigue, anorexia, back pain, and weight loss). The risk of infective endocarditis is higher in younger patients with mild valvular deformity than in older patients with degenerated calcified aortic valves, but it can occur in either population. It can occur in patients of any age with hospital-acquired Staphylococcus aureus bacteremia.

Patients with bicuspid valve have an increased incidence of aortic root dilatation (25-40% of patients) and aortic dissection.

Calcific aortic stenosis rarely may cause emboli of calcium to various organs, including the heart, kidney, and brain.

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Physical Examination

In severe aortic stenosis, the carotid arterial pulse typically has a delayed and plateaued peak, decreased amplitude, and gradual downslope (pulsus parvus et tardus). However, in elderly individuals with rigid carotid vessels, this sign may not be present. A lag time may be present between the apical impulse and the carotid impulse.

Systolic hypertension can coexist with aortic stenosis. However, a systolic blood pressure higher than 200 mmHg is rare in patients with critical aortic stenosis.

Pulsus alternans can occur in the presence of LV systolic dysfunction. The jugular venous pulse may show prominent a waves reflecting reduced right ventricular compliance consequent to hypertrophy of the interventricular septum.

A hyperdynamic LV is unusual and suggests concomitant aortic regurgitation or mitral regurgitation.

S1 is usually normal or soft. The aortic component of the second heart sound, A2, is usually diminished or absent, because the aortic valve is calcified and immobile and/or the aortic ejection is prolonged and it is obscured by the prolonged systolic ejection murmur. The presence of a normal or accentuated A2 speaks against the presence of severe aortic stenosis.

Paradoxical splitting of the S2 also occurs, resulting from late closure of the aortic valve with delayed A2. P2 may also be accentuated in the presence of secondary pulmonary hypertension.

An ejection click is common in children and young adults with congenital aortic stenosis and mobile valve leaflets, but it is rare in elderly individuals with acquired calcific aortic stenosis, in whom the cusps become immobile and severely calcified. This sound occurs approximately 40-60 milliseconds after the onset of S1 and is frequently heard best along the mid to lower left sternal border; it is often well transmitted to the apex and may be confused with a split S1.

A prominent S4 can be present and is due to forceful atrial contraction into a hypertrophied left ventricle. The presence of an S4 in a young patient with aortic stenosis indicates significant aortic stenosis, but with aortic stenosis in an elderly person, this is not necessarily true.

Systolic murmur

The classic crescendo-decrescendo systolic murmur of aortic stenosis begins shortly after the first heart sound. The intensity increases toward mid systole, then decreases, and the murmur ends just before the second heart sound. It is generally a rough, low-pitched sound that is best heard at the second intercostal space in the right upper sternal border. It is harsh at the base and radiates to 1 or both carotid arteries.

In elderly persons with calcific aortic stenosis, however, the murmur may be more prominent at the apex, because of radiation of its high-frequency components (Gallavardin phenomenon). This may lead to its misinterpretation as a murmur of mitral regurgitation. Accentuation of the aortic stenosis murmur following a long R-R interval (as in atrial fibrillation or following a premature beat) distinguishes it from the mitral regurgitation murmur, which usually does not change.

The intensity of the systolic murmur does not correspond to the severity of aortic stenosis; rather, the timing of the peak and the duration of the murmur corresponds to the severity of aortic stenosis. The more severe the stenosis, the longer the duration of the murmur and the more likely it peaks at late systole.

The murmur of valvular aortic stenosis is augmented upon squatting or following a premature beat; the murmur intensity is reduced during Valsalva strain. This is contrary to what occurs with hypertrophic obstructive cardiomyopathy, in which a Valsalva maneuver increases the intensity of the murmur.

When the left ventricle fails and cardiac output falls, the aortic stenosis murmur becomes softer and may be barely audible. Atrial fibrillation with short R-R intervals can also decrease the murmur intensity or make it inaudible.

Other findings

A high-pitched, diastolic blowing murmur may be present if the patient has associated aortic regurgitation.

Rarely, right ventricular failure with systemic venous congestion, hepatomegaly, and edema precede LV failure. This is probably due to the bulging of the interventricular septum into the right ventricle, with impedance in filling, elevated jugular venous pressure, and a prominent venous "a" wave (Bernheim effect).

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Approach Considerations

Diagnostic studies in the emergency department should include electrocardiography (ECG), chest radiography, serum electrolyte levels, cardiac biomarkers, and a complete blood count (CBC). Arterial blood gas measurements are generally not necessary but may be obtained if hypoxemia or a mixed respiratory disease state is suspected.

Multimodality imaging is essential for preoperative planning and postoperative detection of potential complications.^[20] Two-dimensional and Doppler echocardiography is the imaging modality of choice to diagnose and determine the severity of aortic stenosis.^[5] In general, cardiac catheterization is not necessary to determine the severity of aortic stenosis. However, in instances in which clinical findings are not consistent with echocardiogram results, cardiac catheterization is recommended for further hemodynamic assessment.

Go to Imaging in Aortic Stenosis for more complete information on this topic.

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Echocardiography

Two-dimensional transthoracic echocardiography can confirm the clinical diagnosis of aortic stenosis and provide specific data on LV function. The etiology of aortic stenosis (bicuspid, rheumatic, or degenerative calcific) may be assessed from the 2D echocardiographic, parasternal, short-axis view. The structure and function of the other heart valves can also be assessed.

The following 3 echocardiographic findings are indicative of severe aortic stenosis:

• An echo-dense aortic valve with no cusp motion (may be unreliable in congenital or rheumatic valvular stenosis)
• A decrease in the maximal aortic cusp separation (< 8 mm in the adult)
• The presence of otherwise unexplained LV hypertrophy

Although the presence of aortic stenosis is readily diagnosed with 2D echocardiography, the severity of aortic stenosis cannot be judged based on the 2D echocardiographic images alone. Doppler echocardiography is an excellent tool for assessing the severity of aortic stenosis.

Using the modified Bernoulli equation, a maximum instantaneous and mean aortic valve gradient can be derived from the continuous-wave Doppler velocity across the aortic valve. In a laboratory with experienced personnel, Doppler-derived aortic valve gradients are accurate and reproducible and correlate well with those obtained during cardiac catheterization.

The transvalvular gradient is dependent on the severity of obstruction and the flow across the valve. In patients with low cardiac output, the valvular stenosis may be severe even though the transvalvular gradient is low. To overcome this problem, 2D Doppler echocardiography can also provide a reliable estimation of aortic valve area (AVA). The echocardiographic criteria for assessment of aortic stenosis severity are outlined below, in Table 2.

Table 2. Criteria for Determining Severity of Aortic Stenosis

View Table

See Table

Color Doppler valve analysis during transesophageal echocardiography (TEE) can be used to accurately diagnose bicuspid aortic valve in patients with severe symptomatic aortic stenosis, according to a prospective study of 51 patients. In detecting bicuspid aortic valve, color Doppler TEE had a sensitivity of 95.5%, a specificity of 96.5%, and a positive predictive value of 95.5%.^[21]

The major limitation of Doppler echocardiography in assessing the severity of aortic stenosis is underestimation of the gradient if the sound beam is not parallel to the aortic stenosis velocity jet. Thus, in a patient with clinical features of severe aortic stenosis but echo/Doppler findings of mild to moderate aortic stenosis, further evaluation with repeat Doppler or cardiac catheterization may be required.

Rarely, Doppler may overestimate the severity of aortic stenosis in patients with severe anemia (hemoglobin < 8 g/dL), a small aortic root, or sequential stenoses in parallel (coexistent LV outflow tract [LVOT] and valvular obstruction).

Furthermore, echocardiographic calculation of AVA is highly dependent on accurate measurement of the diameter of the LVOT. In patients with poor transthoracic echocardiographic images, TEE may be used to measure the mean and peak gradient and a planimeter may be used to assess the AVA.

In patients who are potential candidates for transcatheter aortic valve replacement (see below), the role of echocardiography is critical. For this reason, the European Association of Echocardiography (EAE) and American Society of Echocardiography (ASE) have published recommendations for the use of echocardiography in patients undergoing transcatheter aortic valve replacement.^[22]

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Cardiac Catheterization and Coronary Arteriography

Cardiac catheterization provides an accurate measure of aortic stenosis and is an important tool, particularly in patients who have discrepant clinical and echocardiographic findings.^[4] In general, if clinical findings are not consistent with Doppler echocardiogram results, cardiac catheterization is recommended for further hemodynamic assessment. 

Measuring the LV end-diastolic and systolic volume and calculating the EF can quantitate the status of LV systolic pump function. However, EF may underestimate LV performance in the presence of the increased afterload associated with severe aortic stenosis. Since bolus administration of contrast may provoke hemodynamic compromise and assessment of LV function can usually be obtained via echocardiography, contrast ventriculography is rarely indicated.

Exclusion of coronary artery disease by coronary angiography is important in all patients older than 35 years who are being considered for valve surgery. Coronary angiography should also be performed in patients younger than 35 years if they have LV systolic dysfunction, symptoms or signs suggestive of coronary artery disease, or 2 or more risk factors for premature coronary artery disease, excluding gender. Generally, the incidence of associated coronary artery disease has been reported to be 50% in patients with aortic stenosis who are older than 50 years. Coronary angiography need not be performed in young patients with no atherosclerotic risk factors and in circumstances where the risk involved outweighs the benefits.^[5]

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Radionuclide Ventriculography

Radionuclide studies to evaluate myocardial perfusion at rest and during exertion and exercise may be considered as part of the complete workup of aortic stenosis. Radionuclide ventriculography may provide information on LV function, including LVEF, ESV, and EDV. Perform these tests cautiously on symptomatic patients.^[23]

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Exercise Stress Testing

Exercise stress testing is contraindicated in symptomatic patients with severe aortic stenosis, but it may be considered in asymptomatic patients with severe aortic stenosis. In asymptomatic patients, stress testing has been shown to be a low-risk procedure when it is performed under strict surveillance.^[23]

Closely monitored exercise stress testing may be of value to assess exercise capacity in asymptomatic patients. Abnormal results may prove greater disability than the patient would admit. In addition to watching for symptoms on the treadmill, one should also look for hemodynamic abnormalities, such as blood pressure decreases or failure to increase blood pressure normally, which can occur in the absence of symptoms. In this setting, the test is not used to screen for coronary disease.

Provocative stress testing is used in cases when the severity of the aortic stenosis is uncertain because of a small stroke volume and a small mean aortic valve gradient (low-gradient aortic stenosis). Infusion of an inotropic agent such as dobutamine, which results in an increase in stroke volume and heart rate, is usually helpful in establishing the correct diagnosis. Cardiac output and LV and aortic pressures are measured simultaneously and AVA is calculated before and during dobutamine infusion.

In patients with an initially low-pressure gradient but severe aortic stenosis, the measured AVA does not change with an intravenous dobutamine infusion, but the mean-pressure gradient increases significantly. In contrast, in patients who have a low cardiac output due to concomitant myocardial dysfunction rather than due to severe aortic stenosis alone, a small increase in the measured AVA and the aortic valve gradient usually occurs with dobutamine infusion.

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Investigational Imaging Modalities

Three-dimensional (3D) volume quantification of aortic valve calcification using multislice computed tomography (CT) scanning demonstrates a close, nonlinear relationship to echocardiographic parameters for the severity of aortic stenosis.^{[5, 24]} This method is not yet clinically validated.

In a study by Shah et al that compared multidetector CT scanning with TEE, multidetector CT scanning was found to be an accurate modality for determining aortic valve measurements in patients with aortic stenosis.^[25]

Cardiac magnetic resonance imaging (MRI) has also been investigated for assessment of aortic stenosis. AVA measurements made with cardiac MRI have shown excellent correlation with those made with Doppler echocardiography. This method is not yet clinically validated.

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Chest Radiography

Even in the presence of significant aortic stenosis, the cardiac size often is normal, with rounding of the LV border and apex. Poststenotic dilatation of the ascending aorta is common.

On lateral views, aortic valve calcification is found in almost all adults with hemodynamically significant aortic stenosis. Although its absence on fluoroscopy in individuals older than 35 years rules out severe valvular aortic stenosis, its presence does not prove severe obstruction in individuals older than 60 years.

The left atrium may be slightly enhanced, and pulmonary venous hypertension may be seen. In later, more severe stages of aortic stenosis, radiographic signs of left atrial enlargement, pulmonary artery enlargement, right-sided enlargement, calcification of the aortic valve, and pulmonary congestion may be evident.

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Electrocardiography

Generally, ECG is not a reliable test for aortic stenosis. The results vary widely in patients with this disorder and overlap with other cardiac conditions.

Although the ECG findings may be entirely normal, the principal finding is left ventricular hypertrophy (LVH), which is found in 85% of patients with severe aortic stenosis; however, its absence does not preclude critical aortic stenosis. Patients with significant aortic stenosis who may not show clear ECG evidence of ventricular hypertrophy include elderly persons with significant myocardial fibrosis and adolescents, who may experience ST-segment changes before QRS changes.

T-wave inversion and ST-segment depression in leads with predominantly positive QRS complexes are common. ST depression exceeding 0.3 mV in patients with aortic stenosis indicates LV strain and suggests severe LVH. Occasionally, a septal pseudoinfarct pattern can be seen. Left atrial enlargement with a preterminal negative p wave in lead V1 is noted in 80% of cases of severe isolated aortic stenosis. The presence of left atrial enlargement suggests an associated mitral valve process.

The correlation between absolute voltages in precordial leads and the severity of obstruction, unlike in children with congenital aortic stenosis, is poor in adults.

The rhythm usually is normal sinus. Atrial fibrillation can be seen at late stages or as a consequence of coexistent MV disease or hyperthyroidism.

Extension of calcification into the conduction system can cause atrioventricular or intraventricular block in 5% of cases of aortic stenosis. Approximately 10% of all cases of left anterior fascicular block are secondary to calcific aortic valve disease. Ambulatory ECG monitoring frequently shows complex ventricular arrhythmias, particularly in cases with myocardial dysfunction.

While the degree of severity of changes on a single ECG does not correlate well with the degree of hemodynamic compromise, serial ECGs performed over time (months to years) can be valuable in demonstrating the progression of the disease.

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B-Type Natriuretic Peptide

B-type natriuretic peptide (BNP) may provide incremental prognostic information in predicting symptom onset in asymptomatic patients with severe aortic stenosis.^[2] A high or steadily rising BNP may predict the short-term need for valve replacement in asymptomatic, severe aortic stenosis. Preoperative BNP provides prognostic information on postoperative outcome.^[26]

In evaluating data from a Japanese multicenter registry comprising 3815 patients with severe aortic stenosis, investigators assessed BNP levels in the 387 patients who had asymptomatic severe aortic stenosis with normal left ventricular ejection fraction and who were not referred for aortic valve replacement.^[3] They found that increased BNP levels were associated with a greater risk for aortic stenosis-related adverse events (aortic valve-related death or heart failure hospitalization) in these patients, whereas there was a relatively low event rate in asymptomatic patients with BNP levels below 100 pg/mL.^[3]

Go to Natriuretic Peptides in Congestive Heart Failure for more complete information on this topic.

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Approach Considerations

The only definitive treatment for aortic stenosis in adults is aortic valve replacement, performed surgically or percutaneously. The development of symptoms due to aortic stenosis provides a clear indication for replacement. For patients who are not candidates for aortic replacement, percutaneous aortic balloon valvuloplasty may provide some symptom relief.^{[4, 5]}   Infants, children and adolescents with a bicuspid valve may undergo balloon or surgical valvotomy. 

The Leadership Council of the American College of Cardiology (ACC) recommends considering percutaneous coronary intervention (PCI) in all patients with significant proximal coronary stenosis in major coronary arteries before transcatheter aortic valve replacement (TAVR), even though the indication is not covered in current guidelines.^[27]

Medical treatment (such as diuretic therapy) in aortic stenosis may provide temporary symptom relief but is generally not effective long term.

In truly asymptomatic patients with severe aortic stenosis, the issue of valve replacement is less clear.^[5]

Consultation with a cardiologist or cardiothoracic surgeon is appropriate.

• References

Emergency Department Care

Prehospital and emergency department management is focused on acute exacerbations of the symptoms of aortic stenosis. As always, assess and address airway, breathing, and circulation. If the patient is in cardiopulmonary arrest, perform resuscitation according to the recommendations of the AHA in their Advanced Cardiac Life Support guidelines. In patients with acute symptoms, hospital admission, telemetry/intensive care unit admission, and cardiology consultation all should be considered.

A patient presenting with uncontrolled heart failure should be treated supportively with oxygen, cardiac and oximetry monitoring, intravenous access, loop diuretics, nitrates (remembering the potential nitrate sensitivity of patients with aortic stenosis), morphine (as needed and tolerated), and noninvasive or invasive ventilatory support (as indicated). Patients with severe heart failure due to aortic stenosis that is resistant to medical management should be considered for urgent surgery.

A patient presenting with angina pectoris requires monitoring and studies as listed above. Measures should be taken to relieve the chest discomfort. This may include the administration of nitrates, oxygen, and morphine. However, nitroglycerin-induced syncope occurs more often in patients with aortic stenosis than in those without aortic stenosis. This information should be obtained through the history at presentation.

Syncope in the face of aortic stenosis should be assessed and treated as in any patient presenting with a syncopal episode.

Atrial fibrillation in the setting of aortic stenosis is considered a medical emergency, and sinus rhythm should be restored urgently in patients who are hemodynamically unstable. Associated symptoms also should be treated urgently.

• References

Percutaneous Balloon Valvuloplasty

Percutaneous balloon valvuloplasty is used as a palliative measure in critically ill adult patients who are not surgical candidates or as a bridge to aortic valve replacement in critically ill patients. The high rate of restenosis and the absence of a mortality benefit preclude its use as a definitive treatment method in adults with severe aortic stenosis.

Valvuloplasty can be considered in cases of severe heart failure or cardiogenic shock for the following patients:

• Patients with other comorbid conditions with a very short life expectancy
• Patients who refuse surgery
• Patients with heart failure who need an urgent, major noncardiac surgical procedure
• Pregnant patients with critical aortic stenosis

In critically ill patients, the mortality rate associated with the procedure is 3-7%. Another 6% develop serious complications, including perforation, myocardial infarction, and severe aortic regurgitation.

In children, adolescents, and young adults with congenital aortic stenosis, percutaneous balloon valvuloplasty carries a mortality risk of 1% and may be an alternative to surgical valvotomy. The risk of causing significant aortic regurgitation is 10%. Although exercise restriction is sometimes recommended to avoid the risk of sudden unexpected death for some patients with congenital aortic stenosis, a recent study by Brown et al suggests that sudden unexpected death is extremely rare following balloon valvuloplasty, and the study found no beneficial effect for exercise restriction after the procedure is performed.^[28]

The best results from valvuloplasty are obtained in the patients with a commissural bicuspid aortic valve, in whom a 60-70% reduction in gradient and a 60% increase in the AVA can be expected.

Restenosis is common, particularly in patients with unicuspid valves or with valves affected by severe dysplasia (>60% at 6 mo, virtually 100% at 2 y). However, repeat procedures have been shown to provide a median survival rate of approximately 3 years and to maintain clinical improvement.^[29]

• References

Aortic Valve Replacement

In most adults with symptomatic, severe aortic stenosis, aortic valve replacement is the surgical treatment of choice. If concomitant coronary disease is present, aortic valve replacement and coronary artery bypass graft (CABG) should be performed simultaneously. Successful aortic valve replacement produces substantial clinical and hemodynamic improvement in patients with aortic stenosis, including octogenarians. 

Aortic valve replacement improves outcomes in patients with low-flow aortic stenosis.^[13] Transcatheter aortic valve replacement (TAVR) may be a preferred therapy in this subset of aortic stenosis patients.

Bioprosthetic and mechanical valves

The choice of prosthesis is determined by the anticipated longevity of the patient and his/her ability to tolerate anticoagulation.^[30]

Stassano et al found that bioprosthetic aortic valves were significantly less durable than were mechanical valves. In a prospective, randomized study of 310 patients aged 55-70 years, follow-up at 13 years showed that valve failures and reoperations were more frequent in the bioprosthesis group than in the mechanical prosthesis group. However, there were no differences between the two types of valves regarding the rates of survival, thromboembolism, bleeding, endocarditis, and major adverse prosthesis-related events.^[31]

The surgical mortality risk in patients with normal LV systolic function and no other comorbid conditions is less than 5%. Risk factors for increased operative mortality include the following:

• High New York Heart Association (NYHA) class (25-30% mortality in patients with class IV)
• Preoperative LV systolic dysfunction
• Older age
• Associated aortic regurgitation

Overall, the 5-year survival rate in all adults after aortic valve replacement is 80-94%, and the 10-year survival rate is 68-89%. Risk factors for late death include the following:

• High preoperative NYHA class
• LV systolic dysfunction
• Preoperative ventricular arrhythmias
• Concomitant aortic regurgitation
• Atrial fibrillation
• Coronary artery disease, particularly a history of myocardial infarction

Ross procedure

The Ross procedure is another option in young patients as an initial procedure or for reoperation after prior valvotomy. In this procedure, the patient's own pulmonary valve and main pulmonary artery are transplanted to the aortic position, with reimplantation of coronary arteries. A homograft is placed in the pulmonary position. Its durability may be better than tissue valves. However, the Ross procedure is technically demanding and results at different centers have been mixed.

Percutaneous transcatheter valve replacement

Many patients with severe aortic stenosis and coexisting conditions are not candidates for, or are at high risk for complications with, surgical replacement of the aortic valve. Studies have suggested that percutaneous transcatheter aortic-valve replacement (TAVR) with a balloon-expandable bovine pericardial valve is a less invasive option for these high-risk patients.^{[5, 32, 33]} In a study comparing TAVR (via a transfemoral or a transapical approach) and surgical replacement in patients who were candidates for valve replacement but considered to be high risk, survival at 1 year was similar for both procedures.^[34] However, important differences in periprocedural risks were observed; major vascular complications and stroke were more frequent with TAVR, whereas major bleeding and new-onset atrial fibrillation were more frequent with surgical valve replacement.

A comprehensive literature review by Daneault evaluated the incidence of stroke after surgical and transcatheter treatment for aortic stenosis. The risk of stroke for the general population after aortic valve replacement was 1.5% (2-4% in higher risk and elderly patients). The rate after transcatheter treatment was 1.5-6%. This review shows a trend for more strokes in the transcatheter group.^[35]

In the Placement of Aortic Transcatheter Valves (PARTNER) trial, inoperable patients with severe aortic stenosis had improved survival with TAVR compared with medical management.^[36] In high-risk patients, survival was similar with TAVR and surgical aortic valve replacement. In all the patient cohorts, low flow (stroke volume index ≤35 mL/m²) was an independent predictor of mortality, whereas low ejection fraction and mean gradient were not.^[36]

Also in the PARTNER trial, patients with critical aortic stenosis after either surgical aortic valve replacement (SAVR) or TAVR showed decreased aortic valve gradients and increased effective orifice area (EOA) on echocardiography through 2 years of follow-up.^[37] Univariate postimplantation echocardiographic predictors of death in the TAVR group were as follows:

• Larger left ventricular systolic and diastolic volumes
• Larger EOA
• Greater aortic regurgitation
• Decreased ejection fraction

In the SAVR group, the predictors of death were as follows:

• Smaller left ventricular systolic and diastolic volumes
• Smaller EOA
• Low stroke volume
• Prosthesis-patient mismatch

Five-year outcomes from the PARTNER trial showed similar outcomes between high-risk patients with aortic stenosis who underwent TAVR and those who underwent surgical aortic valve replacement (SAVR).^[38] At 5 years, risk of death was 67.8% in the TAVR group versus 62.4% in the SAVR group. Neither group reported structural valve deterioration requiring surgical valve replacement. However, moderate or severe aortic regurgitation occurred in 40 of 280 (14%) patients in the TAVR group but in only 2 of 228 (1%) patients in the SAVR group; this was associated with increased 5-year risk of mortality in the TAVR group.^[38]

In another randomized study, TAVR using a self-expanding transcatheter aortic-valve bioprosthesis (CoreValve) was associated with a significantly higher survival rate at 1 year follow-up than surgical aortic-valve replacement.^{[39, 40]} The study consisted of 795 patients with severe aortic stenosis who were at increased surgical risk. The rate of death from any cause at 1 year was 14.2% in the TAVR group and 19.1% in the surgical group (P = 0.04). The risk of stroke at 30 days was 4.9% with TAVR and 6.2% with surgery.^{[39, 40]}

In June 2014, the FDA widened the indication for the self-expanding transcatheter aortic-valve bioprosthesis CoreValve to include patients with symptomatic severe aortic stenosis who are at high risk for surgery.^{[41, 42]} The original indication approved in January 2014 was for patients considered at extreme risk and thus not surgical candidates.^[41]

Approval for the expanded indication was based on data from the head-to-head High-Risk Study of the CoreValve US Pivotal Trial, in which patients who underwent TAVR with CoreValve had a significantly higher 1-year survival rate (85.8%) compared with those who underwent surgical valve replacement (80.9%).^{[41, 42]} The rates of stroke were low and similar between the groups; however, relative to those who received a surgical valve, rates of major adverse cardiovascular/cerebral events were significantly better at 1 year and overall hemodynamic performance was better at all time points in those who underwent TAVR with CoreValve.^[42]

In the ADVANCE study (ArmeD SerVices TrAuma RehabilitatioN OutComE), Linke et al found that implantation of a self-expanding transcatheter aortic valve system (CoreValve System) resulted in a significant improvement in hemodynamics and an increase in the effective aortic valve orifice area in high-risk patients with severe aortic stenosis.^[43] Major adverse cardiovascular and cerebrovascular events were 8.0% at 30 days and 21.2% at 12 months; all-cause mortality was 4.5% and 17.9%, respectively; cardiovascular mortality was 3.4% and 11.7%, respectively; and rate of stroke was 3.0% and 4.5%, respectively.^[43]

In a retrospective study (2007-2013) of data from 714 Canadian patients with severe aortic stenosis who underwent transfemoral TAVR to evaluate outcomes of balloon-expandable (n = 317) versus self-expandable (n = 397) transcatheter heart valves, investigators found no difference in mortality or all-cause readmission rates between the two groups.^[44] However, the safety profile revealed patients in the balloon-expandable group had higher incidences of complications with vascular access sites, compared with those in the self-expandable group who were significantly more likely to suffer an inhospital stroke and have a need for a second transcatheter heart valve device or permanent pacemaker.^[44]

• References

Medical Treatment

The medical treatment options are limited in symptomatic patients with aortic stenosis who are not candidates for surgery. In patients with pulmonary congestion, cautious use of digitalis, diuretics, and angiotensin-converting enzyme (ACE) inhibitors might attempted, whereas beta-blockers might be used if the predominant symptom is angina. In any case, excessive decrease in preload or systemic arterial blood pressure should be avoided.

Vasodilators may be used for heart failure and for hypertension but should also be employed with extreme caution to avoid critically reducing preload or systemic arterial blood pressure in a patient with significant aortic stenosis.

Severe hypertension is frequently seen in the elderly patient with aortic stenosis and should be treated, because it causes an additional increase in vascular afterload. Treatment should follow the guidelines set out in the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure.^[45] Reducing the blood pressure to normal levels is advisable, but hypotension must be avoided.^[5]

The ESC/EACTS guidelines recommend that patients with heart failure symptoms who are not suitable candidates for surgery or transcatheter aortic valve implantation may be treated with digoxin, diuretics, ACE inhibitors, or angiotensin receptor blockers.^[5]

Endocarditis prophylaxis

Antibiotic prophylaxis for the prevention of bacterial endocarditis is no longer recommended in patients with valvular aortic stenosis.

Activity

Patients with mild aortic stenosis can lead a normal life. In cases of moderate aortic stenosis, moderate to severe physical exertion and competitive sports should be avoided.

• References

Prevention/Deterrence

Although small, observational studies have suggested that statin use can reduce aortic valve leaflet calcification and delay the progression of aortic stenosis severity,^[46] 3 randomized, double-blind, placebo controlled trials of almost 2200 patients showed that intensive lipid-lowering therapy does not halt the progression of calcific aortic stenosis or induce its regression.^{[47, 48, 49]}

• References

Long-Term Monitoring

The frequency of the follow-up visits in asymptomatic patients is determined by the severity of aortic stenosis and by the presence of comorbid conditions.

In patients with mild aortic stenosis, yearly history and physical examination and an echocardiogram every 3-5 years are appropriate.

Patients with moderate or severe aortic stenosis should be examined twice yearly and whenever they develop symptoms that are potentially attributable to aortic stenosis.

In patients with moderate aortic stenosis, echocardiograms should be performed every 2 years, whereas in asymptomatic patients with severe aortic stenosis, yearly echocardiograms are recommended.

Following aortic valve replacement, every patient should undergo echocardiographic examination after recovery. Thereafter, an examination is recommended whenever new symptoms develop that are attributable to a potential valvular dysfunction.

Patients with mechanical valves should receive lifelong anticoagulation with warfarin and should undergo periodic screening of their anticoagulation status.

• References

Guidelines Summary

2017 multisociety appropriate use criteria

In 2017, the first document to address appropriate use criteria for the treatment of severe aortic stenosis was released as a collaborative effort by the American College of Cardiology (ACC) Appropriate Use Criteria Task Force, American Association for Thoracic Surgery (AATS), American Heart Association (AHA), American Society of Echocardiography (ASE), European Association for Cardio-Thoracic Surgery (EACTS), Heart Valve Society (HVS), Society of Cardiovascular Anesthesiologists (SCA), Society for Cardiovascular Angiography and Interventions (SCAI), Society of Cardiovascular Computed Tomography (SCCT), Society for Cardiovascular Magnetic Resonance (SCMR), and Society of Thoracic Surgeons (STS).^{[50, 51]}  Eight key recommendations are outlined below.

Asymptomatic patients with high-gradient severe aortic stenosis

No intervention is appropriate or intervention may be considered for those with a left ventricular ejection fraction (LVEF) of at least 50%, V_max 4.0-4.9 m/s, negative exercise stress, and no predictors of rapid progression.

Intervention is appropriate or no intervention may be considered for those with a high-risk profession or lifestyle and low surgical risk, or for those with a predictor of rapid progression. Intervention is appropriate for those with very severe aortic stenosis (V_max ≥5.0 m/s or mean gradient ≥60 mmHg) and low surgical risk, and it is appropriate or may be considered for those at intermediate or high surgical risk.

Intervention is appropriate for patients with an abnormal exercise test, an LVEF below 50%, or when undergoing another cardiac surgical procedure.

Low-flow (LF) low-gradient (LG) severe aortic stenosis and reduced LVEF (< 50%)

Intervention is appropriate for patients with LFLG severe aortic stenosis and an LVEF of 20-49% with flow reserve on low-dose dobutamine stress echocardiography (DSE); intervention is appropriate or balloon aortic valvotomy (BAV) or no intervention may be considered for patients with no flow reserve, but with a very calcified aortic valve suggestive of truly severe aortic stenosis.

For patients with an LVEF below 20%, intervention is appropriate or BAV may be considered for patients with severe high-gradient aortic stenosis, or for patients with LFLG aortic stenosis and flow reserve on DSE.

Intervention is inappropriate for patients with pseudo-severe aortic stenosis; or for patients with an LVEF below 20%, mean gradient less than 20 mmHg, and no flow reserve on DSE.

LG severe aortic stenosis and preserved LVEF (≥50%)

Intervention is appropriate for patients with severe aortic valve calcification, symptoms referable to aortic stenosis, and the following:

• LFLG severe aortic stenosis 
• Normal flow (NF) LG aortic stenosis

Symptomatic severe aortic stenosis and high or extreme surgical risk

For symptomatic patients with an STS predicted risk of mortality (STS-PROM) of 8-15% due to multiple comorbidities, transcatheter aortic valve replacement (TAVR) is appropriate and surgical AVR (SAVR) may be reasonable if the anticipated life expectancy is greater than 1 year; neither TAVR nor SAVR is reasonable if the anticipated life expectancy is less than 1 year.

For patients with an STS-PROM above 15% due to multiple comorbidities, TAVR is appropriate if the health status appears influenced more by aortic stenosis than by comorbidities and the anticipated life expectancy is longer than 1 year.

For patients with an STS-PROM of 8-15% due to frailty with symptoms of fatigue but no chest pain, syncope, or shortness of breath, TAVR is appropriate if B-type natriuretic peptide (BNP) is elevated or if the aortic stenosis is very severe (V_max ≥5 m/s).

TAVR is appropriate for patients with severe symptomatic aortic stenosis and porcelain aorta or hostile chest.

Symptomatic severe high-gradient aortic stenosis with associated coronary artery disease (CAD)

For patients with 1- or 2-vessel CAD:

• SAVR plus coronary artery bypass grafting (CABG) is appropriate for low, intermediate, or high surgical risk;
• TAVR plus percutaneous coronary intervention (PCI) is appropriate for patients at intermediate or high surgical risk; and
• SAVR plus PCI may be appropriate in the absence of proximal left anterior descending artery (LAD) involvement

For patients with 3-vessel CAD:

• SAVR plus CABG is appropriate for low, intermediate, or high surgical risk and regardless of the SYNTAX (Synergy between percutaneous coronary intervention with Taxus and Cardiac Surgery) score; and
• TAVR plus PCI is appropriate for patients at intermediate or high surgical risk and a SYNTAX score below 22

For patients with left main CAD:

• SAVR plus CABG is appropriate for low, intermediate, or high surgical risk and regardless of the SYNTAX score;
• TAVR plus PCI is appropriate for patients at intermediate or high surgical risk and a SYNTAX score below 33; and
• TAVR plus PCI may be appropriate for patients at intermediate or high surgical risk and a SYNTAX score of at least 33

Symptomatic severe aortic stenosis with another valve or ascending aorta pathology

SAVR plus surgical mitral intervention is appropriate for patients at low, intermediate, or high surgical risk in the settings of severe primary mitral regurgitation (MR) or severe secondary MR. Either SAVR plus surgical mitral intervention or TAVR plus percutaneous balloon mitral valvotomy (PBMV) is appropriate in the setting of severe rheumatic MS with no contraindication to PMBV and high surgical risk.

SAVR plus surgical tricuspid valve intervention is appropriate for patients at intermediate surgical risk with severe secondary tricuspid regurgitation and dilated right ventricular (RV) or tricuspid annulus, but minimal pulmonary hypertension (PH) regardless of RV systolic function. TAVR alone is appropriate for patients at high surgical risk with severe secondary tricuspid regurgitation and dilated RV or tricuspid annulus, with severe PH and moderate to severe RV dysfunction; in the same patients, SAVR plus tricuspid valve surgery may be appropriate.

SAVR plus ascending aorta repair is appropriate for patients with bicuspid valve and an ascending aorta of at least 4.5 cm at low, intermediate, or high surgical risk; SAVR alone is appropriate for patients with bicuspid valve and an ascending aorta of less than 4.5 cm at low, intermediate, or high surgical risk; TAVR alone may be appropriate in patients with bicuspid valve at high surgical risk regardless of the aorta size.

SAVR plus myectomy is appropriate and SAVR alone may be appropriate for patients with prominent basal septal hypertrophy with outflow tract narrowing and flow acceleration at low, intermediate, or high surgical risk; TAVR alone may be appropriate for patients at high or intermediate surgical risk.

Severe or critical aortic stenosis and major noncardiac surgery

For symptomatic patients with severe aortic stenosis undergoing elective or urgent major noncardiac surgery, aortic valve intervention is appropriate, and BAV may be considered.

For asymptomatic patients with severe aortic stenosis and no evidence of LV decompensation undergoing elective major noncardiac surgery, aortic valve intervention is appropriate, and no intervention may be considered.

For asymptomatic patients with severe aortic stenosis and no evidence of LV decompensation undergoing urgent major noncardiac surgery, aortic valve intervention, no intervention, or BAV may be considered.

Aortic bioprosthesis with structural valve degeneration and severe symptomatic aortic stenosis or aortic regurgitation

SAVR or TAVR is appropriate in patients at intermediate or high surgical risk and a bioprosthesis size of at least 23 mm.

SAVR is appropriate and TAVR may be appropriate in the following patients:

• Those at intermediate or high surgical risk and a bioprosthesis size of 21 mm
• Those at high surgical risk and a bioprosthesis size up to 19 mm

SAVR is appropriate (and TAVR is not appropriate) in patients at intermediate risk and a bioprosthesis size up to 19 mm.

2017 AHA/ACC guidelines for the management of patients with valvular heart disease

In 2017, the AHA/ACC also released a focused update to their 2014 guidelines for the management of patients with valvular heart disease (VHD).^[52]  Their updated recommendations for the treatment of aortic stenosis are summarized below.

Surgical AVR is recommended for symptomatic patients with severe aortic stenosis (Stage D) and asymptomatic patients with severe aortic stenosis (Stage C) who meet an indication for AVR when the surgical risk is low or intermediate.

Surgical AVR or TAVR is recommended for symptomatic patients with severe aortic stenosis (Stage D) and high risk for surgical AVR, depending on patient-specific procedural risks, values, and preferences.

TAVR is recommended for symptomatic patients with severe aortic stenosis (Stage D) and a prohibitive risk for surgical AVR who have a predicted post-TAVR survival greater than 12 months.

TAVR is a reasonable alternative to surgical AVR for symptomatic patients with severe aortic stenosis (Stage D) and an intermediate surgical risk, depending on patient-specific procedural risks, values, and preferences.

2014 multisociety guidelines for the management of valvular heart disease

In 2014, the AHA/ACC released a revision to their 2008 guidelines for the management of patients with VHD^[6] ; and the European Society of Cardiology (ESC) and the European Association for Cardio-Thoracic Surgery (EACTS) issued a revision of its 2007 guidelines in 2012.^[5]  The Society of Thoracic Surgeons (STS) published guidelines for the management of aortic valve disease in 2013.^[53]

The 2014 AHA/ACC guidelines classify progression of valvular aortic stenosis (AS) into four stages (A to D), as summarized below.^[6] :

Stage A: At risk of AS

Stage B: Progressive AS 

Stage C: Asymptomatic severe AS, as follows:

• C1: Asymptomatic severe AS
• C2: Asymptomatic severe AS with LV dysfunction

Stage D: Symptomatic severe AS, as follows

• D1 Symptomatic severe high-gradient AS
• D2 Symptomatic severe low flow/low gradient AS with reduced left ventricular ejection fraction (LVEF)
• D3 Symptomatic severe low gradient AS with normal LVEF or paradoxical low flow severe AS

According to the 2012 ESC/EACTS guidelines, the echocardiographic criteria for defining severe AS also include valve area less than 1.0 cm², mean gradient greater than 40 mmHg, and maximum jet velocity greater than 4 m per second.^[5]

Both the AHA/ACC and ESC/EACTS guidelines require intervention decisions for severe VHD be based on an individual risk-benefit analysis. Improved prognosis should outweigh the risk of intervention and potential late consequences, particularly complications related to prosthetic valves.^{[5, 6]}

Recognizing the known limitations of the EuroSCORE (European System for Cardiac Operative Risk Evaluation) and the STS score, the AHA/ACC guidelines suggest using the STS criteria plus three additional indicators: frailty (using accepted indices), major organ system compromise not improved postoperatively, and procedure-specific impediment when assessing risk.^[6]  

The 2014 AHA/ACC updated guidelines recommendations for AS include the following^{[6, 54]} :

• Patients with signs or symptoms of AS or a bicuspid aortic valve should be evaluated with transthoracic echocardiography (TTE); selected patients with stage D2 AS may be evaluated with low-dose dobutamine stress testing
• Hypertension should be treated in patients at risk for, and with, asymptomatic AS
• Surgical aortic valve replacement (AVR) is recommended for patients who meet an indication for AVR  as summarized below, in Table 3. 

According to the ESC/EACTS guidelines, aortic valve replacement should be performed in all symptomatic patients with severe AS, regardless of left ventricular (LV) function, as survival is better with surgical treatment than with medical treatment.^[5]   

Table 3. Indications for Aortic Valve Replacement in Aortic Stenosis

View Table

See Table

A comparison of recommendations for surgical and transcatheter intervention for AS is provided in Table 4, below.

Table 4. Guideline Recommendations for Aortic Stenosis Intervention

View Table

See Table

In the 2014 joint guidelines on the management of atrial fibrillation (AF), the American College of Cardiology Foundation, American Heart Association, and Heart Rhythm Society (ACCF/AHA/HRS) recommended against the use of dabigatran in patients with AF and a mechanical heart valve. (Class III)^[55]

• References

Medication Summary

Treatment of valvular aortic stenosis is interventional. Medical treatment in aortic stenosis essentially is reserved for patients who have complications of the disorder, such as heart failure, infective endocarditis, hypertension, or arrhythmias.

The medical treatment options are limited in symptomatic patients with aortic stenosis who are not candidates for surgery. In patients with pulmonary congestion, cautious use of digitalis, diuretics, and angiotensin-converting enzyme (ACE) inhibitors might be attempted, whereas beta-blockers might be used if the predominant symptom is angina.

Antibiotic prophylaxis for the prevention of bacterial endocarditis is no longer recommended in patients with valvular aortic stenosis.

• References

Esmolol (Brevibloc)

• Dosing, Interactions, etc.

Clinical Context:  Esmolol is an ultra–short-acting that selectively blocks beta1-receptors with little or no effect on beta2-receptor types. It is particularly useful in patients with elevated arterial pressure, especially if surgery is planned.

• References

Metoprolol (Lopressor, Toprol XL)

• Dosing, Interactions, etc.

Clinical Context:  Metoprolol is a selective beta1-adrenergic receptor blocker that decreases the automaticity of contractions. During intravenous (IV) administration, carefully monitor blood pressure (BP), heart rate, and electrocardiogram (ECG).

• References

Class Summary

The medical treatment options are limited in symptomatic patients with aortic stenosis who are not candidates for surgery. Beta-blockers may be used if the predominant symptom is angina.

• References

Digoxin (Lanoxin)

• Dosing, Interactions, etc.

Clinical Context:  Digoxin enhances myocardial contractility by inhibition of Na+/K+ ATPase, a cell membrane enzyme that extrudes sodium and brings potassium into the myocyte. The resulting increase in intracellular sodium stimulates the sodium-calcium exchanger in the cell membrane, which extrudes sodium and brings in calcium, leading to an increase in intracellular calcium in the sarcoplasmic reticulum of cardiac cells, thereby increasing the contractility of myocytes.

• References

Class Summary

Cardiac glycosides slow AV nodal conduction primarily by increasing vagal tone. Patients with aortic stenosis who are not candidates for surgery and present with pulmonary congestion may be treated with digoxin. Digoxin can also be used as an inotropic agent to control the ventricular rate in patients with atrial fibrillation.

• References

Furosemide (Lasix)

• Dosing, Interactions, etc.

Clinical Context:  Furosemide increases the excretion of water by interfering with the chloride-binding co-transport system, which, in turn, inhibits sodium and chloride reabsorption in the ascending loop of Henle and the distal renal tubule.

• References

Bumetanide (Bumex)

• Dosing, Interactions, etc.

Clinical Context:  Bumetanide increases the excretion of water by interfering with chloride-binding co-transport system, which, in turn, inhibits sodium, potassium, and chloride reabsorption in the ascending loop of Henle. These effects increase urinary excretion of sodium, chloride, and water, resulting in profound diuresis. Renal vasodilation occurs following administration, renal vascular resistance decreases, and renal blood flow is enhanced.

• References

Class Summary

Loop diuretics act on the ascending limb of the loop of Henle, inhibiting the reabsorption of sodium and chloride. Prehospital and emergency department management is focused on acute exacerbations of the symptoms of aortic stenosis. A patient presenting with uncontrolled heart failure should be treated supportively with loop diuretics.

• References

Captopril (Capoten)

• Dosing, Interactions, etc.

Clinical Context:  Captopril prevents conversion of angiotensin I to angiotensin II, a potent vasoconstrictor, resulting in lower aldosterone secretion.

• References

Enalapril (Vasotec)

• Dosing, Interactions, etc.

Clinical Context:  Enalapril prevents the conversion of angiotensin I to angiotensin II, a potent vasoconstrictor, resulting in increased levels of plasma renin and a reduction in aldosterone secretion. It helps control blood pressure and proteinuria. Enalapril decreases pulmonary-to-systemic flow ratio in the catheterization laboratory and increases systemic blood flow in patients with relatively low pulmonary vascular resistance.

• References

Class Summary

These agents are competitive inhibitors of angiotensin-converting enzyme (ACE). They reduce angiotensin II levels, thus decreasing aldosterone secretion.

• References

Morphine sulfate (MS Contin, Astramorph, Avinza)

• Dosing, Interactions, etc.

Clinical Context:  Morphine is a drug of choice for analgesia due to reliable and predictable effects and safety profile. A patient presenting with uncontrolled heart failure due to aortic stenosis should be treated supportively with morphine.

• References

Class Summary

Opioid analgesics such as morphine act by binding to opioid receptors on neurons distributed throughout the nervous system and immune system. They can also help patient anxiety, distress, and dyspnea.

• References