Aortic Stenosis

Aortic Stenosis 

6 Interesting Facts of Aortic Stenosis 

  1. Aortic stenosis is obstruction of left ventricular systolic outflow across the aortic valve at the aortic valve level, due to narrowing of the valve orifice
  2. Symptoms usually develop gradually as the severity of outflow tract obstruction slowly increases over 10 to 15 years, resulting in a long latent period during which stenosis severity is only mild to moderate 
  3. Diagnosis is suggested by history and physical examination and confirmed by echocardiography, which typically shows an increased maximum aortic velocity, an increased mean pressure gradient across the valve, and a decreased aortic valve area
  4. Definitive treatment is aortic valve replacement via either surgical or transcatheter approach
  5. Timing of valve replacement is important; it is generally recommended only for stenosis that meets the definition of severe, symptomatic disease, although some subsets of asymptomatic patients with severe stenosis may benefit from replacement
  6. Transcatheter valve replacement is becoming more common, particularly in patients who are at high surgical risk. It may also be a reasonable choice for some patients at intermediate surgical risk

Pitfalls

  • Vasodilators administered to patients with heart failure can lead to life-threatening hypotension owing to the fixed stenotic valve orifice of severe aortic stenosis
  • Exercise stress testing is contraindicated in symptomatic aortic stenosis owing to risk of complications, including hypotension
  • Multiple comorbidities, common in older patients, may make it difficult to distinguish an asymptomatic from a symptomatic patient in terms of the relative contribution of aortic valve stenosis to symptoms
  • Choice of proceeding with surgical aortic valve replacement versus transcatheter replacement is made by the heart team based on multiple factors, including surgical risk, frailty, comorbidities, and patient preferences; severe multivessel coronary disease may best be served by surgical aortic valve replacement along with coronary artery bypass grafting 
  • Aortic stenosis is obstruction of left ventricular systolic outflow across the aortic valve at the aortic valve level, due to narrowing of the valve orifice
  • Patients usually become symptomatic when maximum aortic velocity is 4 m/second or greater, mean pressure gradient is 40 mm Hg or greater, and aortic valve area is 1 cm² or less 

Classification

  • By stage
    • Based on presence or absence of symptoms, anatomy of the aortic valve area, valve hemodynamics (ie, flow velocity and pressure gradient across the aortic valve), and consequences of valve obstruction on the left ventricle (ie, ejection fraction)
    • Stage A (at-risk): patient is asymptomatic with risk factors for development of valvular heart disease
      • Maximum aortic velocity less than 2 m/second
    • Stage B (progressive): patient is asymptomatic but meets criteria for mild to moderate valvular heart disease
      • Mild: maximum aortic velocity 2 to 2.9 m/second or mean pressure gradient less than 20 mm Hg
      • Moderate: maximum aortic velocity 3 to 3.9 m/second or mean pressure gradient 20 to 39 mm Hg
    • Stage C (asymptomatic/severe): patient is asymptomatic but meets criteria for severe valvular heart disease
      • C1
        • Severe: maximum aortic velocity 4 m/second or greater or mean pressure gradient 40 mm Hg or greater
        • Very severe: maximum aortic velocity 5 m/second or greater or mean pressure gradient 60 mm Hg or greater
      • C2
        • Severe with left ventricular dysfunction: maximum aortic velocity 4 m/second or greater or mean pressure gradient 40 mm Hg or greater; left ventricular ejection fraction less than 50%
    • Stage D (symptomatic/severe): patient is symptomatic and meets criteria for severe valvular heart disease
      • D1: maximum aortic velocity 4 m/second or greater or mean pressure gradient 40 mm Hg or greater; aortic valve area typically 1 cm² or less
      • In contrast to typical aortic stenosis that results in high-flow velocity, 2 subgroups are characterized by low-flow velocity and/or gradient (aortic valve area must be measured to categorize these stages):
        • D2: severe low-flow/low-gradient aortic stenosis with reduced left ventricular ejection fraction; aortic valve area 1 cm² or less with resting maximum aortic velocity less than 4 m/second or mean pressure gradient less than 40 mm Hg
          • Dobutamine stress echocardiography shows aortic valve area 1 cm² or less with maximum aortic velocity 4 m/second or greater at any flow rate
        • D3: severe low-gradient aortic stenosis with normal left ventricular ejection fraction or paradoxical low-flow severe aortic stenosis; aortic valve area 1 cm² or less with maximum aortic velocity less than 4 m/second or mean pressure gradient less than 40 mm Hg; left ventricular ejection fraction is 50% or higher with low stroke volume

Clinical Presentation

History

  • Adults
    • Asymptomatic or mildly symptomatic latent period of 10 to 15 years 
    • Symptoms develop gradually over time; left ventricle outflow obstruction and pressure load on the myocardium steadily increase
    • Exertional dyspnea is the most common presenting symptom
    • The most important symptoms are dyspnea, chest pain, and syncope
    • Patients may also complain of:
      • Fatigability
      • Progressive inability to exercise
    • With more advanced stages, patients may experience:
      • Orthopnea
      • Paroxysmal nocturnal dyspnea
      • Peripheral edema

Physical examination

  • General
    • Labored breathing and peripheral cyanosis may be noted in advanced aortic stenosis
  • Cardiovascular 
    • Pulsus alternans may be seen (rare) with associated left ventricular dysfunction
    • Carotid pulse delay
    • Palpation of a forceful left ventricular/apical beat
    • Auscultation
      • Crescendo-decrescendo or systolic ejection murmur, loudest in the aortic area and radiating toward the carotid arteries (thrill) is highly characteristic and suggestive of aortic stenosis
        • In mild disease, the murmur peaks in intensity earlier in systole
        • In more advanced disease, the murmur peaks later in systole
      • S₁ heart sound
        • Usually normal; however, in children, S₁ may be followed by a systolic ejection click
      • S₂ heart sound
        • A₂ is diminished, while P₂ may be louder
        • If heart failure is present, there may be a single heart sound (only an accentuated P₂)
      • S₄ heart sound (gallop)
        • May be heard, owing to forceful atrial contraction in response to a hypertrophied left ventricle
        • Presence of S₄ heart sound suggests severe aortic stenosis
    • Abdominal
      • Hepatomegaly may be noted in patients with severe aortic stenosis and right-sided heart failure

Causes

  • Progressive fibro-calcific thickening of tricuspid aortic valve
    • Thickening of aortic valve to the point of hemodynamic compromise
    • When hemodynamic compromise has not yet occurred and peak velocity is less than 2 m/second, the condition is called aortic sclerosis 
    • Most commonly has onset of symptoms in eighth decade of life 
  • Progressive fibrosis and calcification of congenital bicuspid valve
    • 1% to 2% of the population is born with bicuspid aortic valve 
    • Bicuspid valves tend to deteriorate with age; symptom onset is decades earlier than with tricuspid calcific stenosis
    • Subset of patients may belong to families with autosomal dominant inheritance 
  • Other, rarer forms of congenital valve disease
    • Can occur from tricuspid, quadricuspid, or unicuspid aortic valve
    • Typically becomes clinically apparent in childhood or early adulthood
  • Rheumatic heart disease
    • Rare in developed countries owing to widely available treatments for streptococcal pharyngitis
    • Typically coexists with mitral valve abnormalities
  • Inherited conditions associated with aortic valve stenosis
    • Alkaptonuria
      • Rare metabolic disorder of tyrosine catabolism that leads to endothelial damage

Risk factors and/or associations

Age
  • Related to underlying cause:
    • Congenital aortic stenosis due to unicuspid or quadricuspid valves manifests in childhood or early adulthood
    • Aortic stenosis due to congenital bicuspid aortic valve typically manifests after age 40 years 
    • Rheumatic heart disease can damage the valve at any age (depending on age at acute group A streptococcal infection); damage can occur in the acute or chronic phase of rheumatic fever
  • In Europe and North America, 12.4% of populations older than 75 years have aortic stenosis, typically calcific 
Sex
  • Calcific disease of tricuspid valve involves both sexes equally
  • Congenital bicuspid aortic valve is more prevalent in men 
Genetics
  • Defects in the NOTCH1 gene have been identified in a small number of families with calcific stenosis of bicuspid aortic valve 
    • Autosomal dominant inheritance (OMIM #109730) 
  • Defects in the SMAD6 gene have been identified in several patients with stenosis of bicuspid aortic valve 
    • Autosomal dominant inheritance (OMIM #614823) 
  • Several other genetic abnormalities relating to inflammation, cholesterol, and lipid metabolism may account for several as-yet unidentified causes of idiopathic calcified valve disease 
Ethnicity/race
  • Despite an adverse cardiovascular risk profile, Black populations have a significantly lower prevalence of valvular stenosis than White populations 
    • Prevalence of congenital bicuspid aortic valve is lower in Black populations than in White populations (9% versus 25%)
    • Presence of calcific aortic stenosis is also lower in Black populations than in White populations (14% versus 28%)

Diagnostic Procedures

Primary diagnostic tools

  • History and physical examination suggest the diagnosis
  • Transthoracic echocardiography with 2-dimensional imaging and Doppler is the standard imaging test indicated for all patients and it correlates anatomic and clinical findings 
  • ECG and chest radiography are not diagnostic, but they should be performed at baseline in all patients 
  • Additional imaging (eg, CT calcium scoring, cardiac catheterization) may be required to determine disease severity and optimal treatment 
  • Exercise testing is reasonable and can be considered in select patients with asymptomatic severe stenosis to: 
    • Confirm absence of symptoms
    • Assess hemodynamic response to exercise
    • Determine prognosis

Imaging

  • Transthoracic 2-dimensional echocardiography with Doppler flow study
    • Echocardiography is the first line and gold standard imaging test for aortic stenosis and is indicated for all patients
    • Useful in determining the severity of aortic stenosis, left ventricular hypertrophy, and systolic function
      • Using transthoracic echocardiography
        • Determine left ventricular size, wall thickness, and systolic function
        • Evaluate for other valvular disease (mitral regurgitation is common in patients with aortic stenosis)
      • Using Doppler
        • Measure maximum aortic velocity, mean pressure gradient, and valve area
        • Validated in experimental and human studies compared with direct measurements of intracardiac pressure and cardiac output
    • Discordant echocardiography refers to results wherein the individual echocardiographic assessments do not agree on severity 
      • Discordant results can occur in 25% to 35% of patients
      • The most common discordant findings are aortic valve area circulation less than 1 cm² and peak velocity less than 4 m/second
      • Stress echocardiography and CT calcium scoring are indicated for patients with discordant echocardiography results to confirm aortic stenosis severity
  • Chest radiography
    • Indicated for all patients
    • Generally nondiagnostic for aortic stenosis, but it is useful to demonstrate pulmonary complications (eg, pulmonary congestion, pleural effusion) in aortic stenosis with heart failure
    • Can also identify cardiomegaly and poststenotic dilation of ascending aorta
    • Calcification of aortic cusps can occasionally be seen on lateral view
  • CT
    • CT coronary angiography can be performed in younger patients and in patients with suspected aortopathy (eg, patients with bicuspid aortic valve disease) 
    • CT angiography results are used in planning transaortic valve replacement
    • In patients with suspected low-flow, low-gradient severe aortic stenosis with normal or reduced left ventricular ejection fraction, measurement of aortic valve calcium score by CT imaging is reasonable to further define severity 
  • Cardiac MRI
    • Not indicated for all patients but is a third or fourth line imaging technique
      • May be useful to rule out obstructive coronary artery disease in patients who are at low risk of atherosclerosis (high negative-predictive value)
      • Can be used to identify underlying bicuspid valve disease and to assess aortic size
      • Provides potentially important information about myocardial fibrosis and left ventricular decompensation
    • Provides risk stratification for timing of intervention

Functional testing

  • ECG
    • Indicated for all patients
    • Left ventricular hypertrophy and evidence of left atrial enlargement are commonly seen; enlargement is resultant from stiff left ventricle
    • Atrial fibrillation occasionally present
    • Left ventricular strain pattern is a specific marker of advanced aortic stenosis and left ventricular decompensation 
      • ECG strain is defined as 1 mm or more concave down-sloping ST-segment depression with asymmetrical T-wave inversion in the lateral leads 
  • Stress testing
    • Symptom-limited graded exercise stress test
      • Can be considered in patients with asymptomatic aortic stenosis, given its prognostic value
        • Criteria associated with poor outcome and considered indications for surgery include:
          • Development of symptoms during exercise, including chest pain or breathlessness
          • Abnormal blood pressure response, including hypotension or failure of an appropriate increase in blood pressure
      • Contraindicated in symptomatic aortic stenosis owing to risk of complications, including hypotension
      • Exercise test is interrupted when target heart rate is attained or if patient develops chest pain, hemodynamic instability, breathlessness, or arrhythmias
    • Symptom-limited graded exercise stress test with echocardiography 
      • Major use of stress test with echocardiography is to clarify aortic stenosis severity in patients with discordant echocardiography and a low flow status
      • Doppler echocardiographic information can be obtained continuously during exercise testing on semisupine bicycle
      • Estimates left ventricle and aortic valve biphasic hemodynamic and mechanical response to exercise
  • Cardiac catheterization
    • When noninvasive data are nondiagnostic or if there is a discrepancy between clinical and echocardiographic evaluation, cardiac catheterization for determination of severity of aortic stenosis can be considered 
    • Left-sided cardiac catheterization
      • Measures pressure gradient across the aortic valve and can calculate aortic valve area using Gorlin formula
      • Risks include stroke from catheter-associated dislodgement of particles from diseased aortic valve
    • Coronary arteriography is typically performed in middle-aged and older adults in whom coexisting coronary artery disease is suspected based on medical history, symptoms, or other testing; if documented, concomitant coronary revascularization is indicated 
      • Specific indications:
        • History of cardiovascular disease
        • 1 or more cardiovascular risk factors
          • Guidelines recommend such testing for all men older than 40 years and postmenopausal women 
        • Suspected myocardial ischemia based on chest pain or abnormal noninvasive test results
        • Left ventricular systolic dysfunction

Differential Diagnosis

Differential diagnosis of aortic stenosis applies to patients presenting with a systolic murmur

Most common

  • Hypertrophic obstructive cardiomyopathy
    • Hypertrophy of the left ventricle with resulting dynamic obstruction of the left ventricular outflow tract
    • Most patients are asymptomatic but suspicion is raised by discovery of a murmur
    • If symptoms occur (may occur at any age), differentiate from aortic stenosis based on the following:
      • A₂ is present and of normal quality (diminished or absent in aortic stenosis)
      • Nature of systolic murmur
        • Loudest in mid- to late-systole and best heard at the left sternal border
        • Valsalva maneuver, inducing a reduced preload, causes the murmur in hypertrophic obstructive cardiomyopathy to increase; in aortic stenosis, the murmur decreases owing to a reduction in the absolute blood volume flowing across the valve
      • Carotid upstroke
        • Rise of upstroke is rapid initially, with notch and then a slow terminal upstroke (upstroke is slow throughout in aortic stenosis)
      • Echocardiography
        • Hypertrophic ventricular septum and abnormal mitral valve tethering toward the septum are noted, in addition to a normal aortic valve
  • Subvalvular aortic stenosis
    • Congenital anomaly
    • Obstruction just proximal to the aortic valve, due to a ring or diaphragm
    • Associated with congenital or acquired (secondary to abnormal flow across valve leaflets) aortic valve disease
    • Differentiated by echocardiography, where the precise level of obstruction can be identified
  • Supravalvular aortic stenosis
    • Congenital anomaly
    • Narrowing of the ascending aorta, usually distal to the coronary arteries
    • Differentiated by physical examination (often a difference in pulse pressure noted between right and left arterial sites [carotid, arm]) and echocardiography, where the precise level of obstruction can be identified
  • Aortic sclerosis
    • Thickening or calcification of the aortic valve in absence of valve obstruction; precursor to aortic stenosis
    • Aortic sclerosis is often an incidental finding on physical examination (systolic murmur), echocardiography, or CT (calcified deposits observed in the valve leaflets)
    • Echocardiography is used to differentiate between aortic sclerosis and aortic stenosis, which will show thickened valve in both, but no obstruction with aortic sclerosis
    • On Doppler echocardiography, the peak aortic valve jet velocity is less than 2 m/second with aortic sclerosis 
  • Mitral regurgitation
    • Leaking of mitral valve, causing backflow of blood from left ventricle to left atrium during ventricular contraction
    • Similar to aortic stenosis, symptoms of mitral regurgitation can include dyspnea, angina, or syncope
    • Murmur of mitral regurgitation is pansystolic, whereas in aortic stenosis it is usually a systolic murmur that peaks in late systole
    • Differentiated from aortic stenosis based on echocardiography
  • Ventricular septal defect
    • Defect in the interventricular septum that results in communication between the 2 ventricles
    • Older children, adolescents, or adults with an unrepaired ventricular septal defect or ventricular septal defect repaired after early childhood may present with symptoms of Eisenmenger syndrome; these may overlap with some symptoms of aortic stenosis such as dyspnea, chest pain, and syncope
    • With ventricular septal defects, a holosystolic murmur is present if left ventricular pressure is higher than right ventricular pressure
    • Differentiated by echocardiography, which in the case of a ventricular septal defect reveals a defect in septum and left-to-right flow

Treatment Goals

  • Improve symptoms
  • Halt progression of left ventricular dysfunction
  • Replace aortic valve at the optimal time

Admission criteria 

Patients presenting with acute heart failure

Patients with severe heart failure due to aortic stenosis that is resistant to medical management should be admitted and considered for surgical treatment

Criteria for ICU admission
  • Aortic stenosis with cardiac and/or hemodynamic instability

Recommendations for specialist referral

  • Refer to cardiologist for assistance with diagnostic evaluation and to direct management
  • When aortic valve replacement intervention is considered, refer to multidisciplinary heart valve team consisting of cardiologist, cardiovascular surgeon, and catheter-based interventionist
  • Optimal care for complex patients is at a Heart Valve Center of Excellence

Treatment Options

Watchful waiting is the only recommended strategy for most asymptomatic patients, unless: 

  • Severe aortic stenosis with left ventricular systolic dysfunction is present, or
  • Abnormal results are encountered with symptom-limited exercise testing

Medical treatment is generally not effective in the long term. No medical treatment has demonstrated the ability to slow the progression of aortic stenosis severity, but it may provide temporary symptom relief

  • In patients with asymptomatic disease (stages A, B, and C), treat hypertension according to hypertension clinical practice guidelines, starting at a low dose and titrating upward gradually, with frequent clinical monitoring 
  • Treat patients with symptomatic heart failure who are unsuitable candidates for surgery or transcatheter aortic valve replacement according to heart failure clinical practice guidelines 
  • Treatment with statins does not affect rate of progression of aortic stenosis or clinical outcomes 
    • In their guideline on valvular heart disease, the American Heart Association/American College of Cardiology state that statin therapy is not indicated for prevention of hemodynamic progression in adults with mild to moderate calcific aortic valve disease 
    • However, statin therapy is indicated for primary and secondary prevention of atherosclerosis in all patients with calcific aortic stenosis, in accordance with risk scores 

The only definitive treatment for aortic stenosis is valve replacement 

  • Choice of an open surgical procedure versus transcatheter aortic valve replacement has traditionally been based on surgical risk category (low, intermediate, or high), with transcatheter approach recommended for patients at high risk
    • Transcatheter aortic valve replacement now appears reasonable in both high- and intermediate-risk patients 
    • Data on transcatheter aortic valve replacement are still very limited for patients younger than 75 years and for surgical low-risk patients; therefore, surgical aortic valve replacement remains the reference method for these patients 
      • Younger patients are more likely to have bicuspid valves, which have been generally excluded in clinical trials of transcatheter aortic valve replacement
      • Long-term durability data for transcatheter prosthetic valves (of greater importance to younger patients) are still lacking
    • An “appropriate use criteria” document has been published; it includes 95 clinical scenarios to provide guidance on selecting the best intervention for an individual patient 

Management after aortic valve replacement

  • Thromboembolism prophylaxis
    • For patients with surgical valve replacement (mechanical valve):
      • Without additional thromboembolism risk factors: warfarin anticoagulation to INR of 2.5 
        • Recognize that the acceptable range includes 0.5 INR units on each side of this target
        • A lower target INR of 1.5 to 2 may be reasonable in patients with a specific type of mechanical valve (On-X) and no thromboembolic risk factors 
      • With additional thromboembolism risk factors (ie, atrial fibrillation, previous thromboembolism, left ventricular dysfunction, or hypercoagulable conditions): anticoagulate to INR of 3 
      • With a mechanical mitral valve prosthesis as well: anticoagulate to INR of 3 
      • The addition of aspirin to warfarin in patients with mechanical valves is controversial; several ongoing trials are examining this issue 
      • Anticoagulant therapy with oral direct thrombin inhibitors or anti-Xa agents should not be used in patients with mechanical valve prostheses 
    • For patients with surgical valve replacement (bioprosthetic valve):
      • Warfarin anticoagulation to INR of 2.5 (for at least 3 months and as long as 6 months) is considered reasonable, in patients at low risk of bleeding 
      • After 6 months, antiplatelet therapy with aspirin is reasonable, but use with caution in those with increased bleeding risk 
    • Patients with transcatheter aortic valve replacement (bioprosthetic valves):
      • Warfarin anticoagulation to INR of 2.5 may be reasonable for the initial 3 to 6 months after transcatheter aortic valve replacement in patients at low risk of bleeding 
      • An alternative is antiplatelet therapy with low-dose (75-100 mg) aspirin plus clopidrogrel 
      • Lifelong, daily low-dose (75-100 mg) aspirin (without warfarin or clopidrogrel) is reasonable, but use with caution in those with increased bleeding risk 
      • Utility of direct-acting oral anticoagulants is unknown in this population
    • Use of antibiotic prophylaxis against infective endocarditis is controversial due to lack of evidence (absence of randomized controlled trials for prevention) 
      • Prophylaxis is recommended before dental procedures that involve manipulation of gingival tissue, manipulation of the periapical region of teeth, or perforation of the oral mucosa
  • Antibiotic prophylaxis against infective endocarditis
    • The American College of Cardiology/American Heart Association suggest that antibiotic prophylaxis is reasonable for the subset of patients at highest risk of developing infective endocarditis and at high risk of experiencing adverse outcomes from infective endocarditis 
      • Risk of developing infective endocarditis is highest in patients with a prosthetic valve, earlier history of infective endocarditis, or congenital heart disease with residual flow disturbances
      • Antibiotic prophylaxis is not recommended for nondental procedures such as colonoscopy

Drug therapy

  • Prophylaxis of endocarditis
    • Amoxicillin
      • Amoxicillin Trihydrate Oral tablet; Adults: 2 g PO as a single dose given 30 to 60 minutes before procedure.
  • Prophylaxis of arterial thromboembolism after valve replacement
    • Warfarin
      • Warfarin Sodium Oral tablet; Adults with mechanical prosthetic aortic valve replacement and no risk factors for thromboembolism: Target INR of 2.5 (range 2 to 3) with aspirin 75 to 100 mg PO daily.
      • Warfarin Sodium Oral tablet; Adults with mechanical prosthetic aortic valve replacement and risk factors for thromboembolism: Goal INR of 3 (range 2.5 to 3.5) with aspirin 75 to 100 mg PO daily.
    • Aspirin
      • Aspirin Oral tablet; Adults: 75 to 100 mg PO once daily indefinitely.
    • Clopidogrel (in addition to aspirin after transcatheter aortic valve replacement)
      • Clopidogrel Bisulfate Oral tablet; Adults: 75 mg PO once daily for 3 to 6 months.

Nondrug and supportive care

Asymptomatic aortic stenosis

  • American College of Cardiology/American Heart Association guideline for the management of patients with valvular heart disease includes a recommendation for evaluation and modification of cardiac risk factors, including: 
    • Discontinuation of tobacco use
    • Participation in regular exercise

Symptomatic aortic stenosis: avoidance of strenuous activity

Procedures
Aortic valve replacement

General explanation

  • Performed via an open surgical or transcatheter approach
    • Open surgical valve replacement
      • Either mechanical valve or bioprosthetic valve is implanted via median sternotomy incision or minimally invasive approach
    • Transcatheter aortic valve replacement
      • Bioprosthetic valve is advanced in retrograde fashion through either femoral or subclavian artery approach or via direct retrograde transaortic access (ministernotomy) approach. Native valve is left in place

Indication

  • Timing of intervention (either open approach or transcatheter aortic valve replacement) depends on presence or absence of symptoms, severity of stenosis, and hemodynamic consequences of the stenosis
    • Asymptomatic patients
      • Recommended for patients with severe aortic stenosis (stage C2) and left ventricular ejection fraction less than 50%
      • Recommended for patients with severe aortic stenosis who are undergoing another planned cardiac operation
      • Considered reasonable for patients with severe aortic stenosis (stage C1), rapid disease progression, and low surgical risk
      • Considered reasonable for patients with moderate (stage B) disease who are undergoing another cardiac operation
    • Symptomatic patients
      • Recommended for patients with severe high-gradient aortic stenosis (stage D1) who have symptoms reported during history or observed on exercise testing
      • Recommended for patients with severe aortic stenosis (stage D) who are undergoing another planned cardiac operation
      • Considered reasonable in symptomatic patients with low-flow/low-gradient severe aortic stenosis with reduced ejection fraction (stage D2) as confirmed during dobutamine stress testing
      • Considered reasonable in symptomatic patients with low-flow/low-gradient severe aortic stenosis (stage D3) with a left ventricular ejection fraction 50% or greater who are normotensive (if valve obstruction is likely cause of symptoms)
  • Choice of intervention, when patient qualifies based on severity, symptoms, and hemodynamics
    • Surgical risk is a major factor, and may be calculated using the Society of Thoracic Surgeons validated online risk calculator 
      • Surgical aortic valve replacement for patients with low surgical risk 
      • Surgical aortic valve replacement (combined with coronary artery bypass grafting) may be best choice for patients with severe, multivessel comorbid coronary artery disease 
      • Surgical aortic valve replacement or transcatheter aortic valve replacement for patients with intermediate surgical risk 
        • Transcatheter aortic valve replacement is considered a reasonable alternative to surgical type
        • Choice depends on patient-specific procedural risks, values, and preferences
        • Randomized controlled trials have shown no difference in all-cause death or disabling stroke at 2 years and 5 years 
      • Surgical aortic valve replacement or transcatheter aortic valve replacement for patients with high surgical risk 
        • Choice depends on patient-specific procedural risks, values, and preferences
        • Consultation with a heart valve team of integrated multidisciplinary professionals is recommended 
      • Transcatheter aortic valve replacement for patients with a prohibitive risk for surgical replacement and who have predicted post–transcatheter replacement survival time of more than 12 months 
        • Valve may be either self-expanding or balloon expandable
  • Type of prosthetic valve
    • Mechanical valve
      • Durable and less likely to need replacement during patient’s lifetime
      • Requires ongoing anticoagulation
      • In general, mechanical prosthesis is reasonable for patients younger than 50 years who do not have a contraindication to anticoagulation 
        • For patients aged between 50 and 70 years, it is reasonable to individualize the choice of either mechanical or bioprosthetic valve prosthesis on the basis of individual patient factors and preferences, after full discussion of the trade-offs involved
    • Bioprosthetic valve
      • Less durable (lasts 10-15 years); avoids need for ongoing anticoagulation 
      • Recommended for patients of any age in whom anticoagulant therapy is contraindicated, cannot be managed appropriately, or is not desired 

Contraindications

  • Bicuspid aortic valve is a relative contraindication to transcatheter aortic valve replacement, although newer-generation valves are promising for this indication 
  • Surgical aortic valve replacement is not recommended for patients with prohibitively high surgical risk 
  • Transcatheter aortic valve replacement is not recommended for patients in whom existing comorbidities would preclude the expected benefits from correction of the aortic stenosis 
Percutaneous aortic balloon valvuloplasty

General explanation

  • Balloon is inserted via the femoral artery and inflated, thereby opening valve

Indication

  • Bridge to surgical aortic valve replacement or transcatheter aortic valve replacement in adults with severe symptomatic stenosis 
  • Useful in infants/children as an alternative to surgery
    • 30% of patients eventually require surgical aortic valve replacement owing to recurrent stenosis or for aortic regurgitation 

Contraindications

  • Patient is a surgical candidate

Comorbidities

  • Cardiac comorbidities are very common
    • Pulmonary hypertension (67%)
      • Associated with increased morbidity and mortality after valve replacement by transcatheter aortic valve replacement and surgical approach
    • Heart failure (57.5% are New York Heart Association functional class III or IV)
      • Patients presenting with class IV heart failure may benefit from a trial of vasodilators to reduce afterload; must be done cautiously with invasive hemodynamic monitoring followed by urgent aortic valve replacement 
      • Patients with heart failure should be treated with diuretics before introduction of vasodilators
      • Prompt aortic valve replacement is required in these patients
    • Coronary artery disease (43.7%)
      • Symptoms may overlap with those of severe aortic stenosis
      • Combined coronary artery bypass grafting–aortic stenosis surgery may be warranted
    • Atrial fibrillation (35.8%)
    • Mitral regurgitation of moderate severity or worse (32.5%)
  • Other comorbidities
    • Risk factors for atherosclerosis are present in many patients
      • Hypertension (82.9%)
        • No studies addressing use of specific medications for this indication; patients with stage A, B, or C aortic stenosis should be managed via goal-directed clinical practice guidelines for hypertension 
          • ACE inhibitors have theoretical benefit
          • Use diuretics cautiously; avoid if left ventricular chamber size is small
        • Vasodilators in particular can cause hypotension and should be used with caution
      • Hyperlipidemia (60%)
        • No evidence that lipid-lowering drugs slow hemodynamic progression of aortic stenosis; statins are not indicated for that purpose. However, they may be indicated for primary or secondary prevention of coronary artery disease if dyslipidemia is present 
      • Diabetes (30%)
        • Manage according to published guidelines
        • Theoretical concern of poorer wound healing after surgery 
        • Transcatheter aortic valve replacement may have survival benefit compared with that of surgical valve replacement, but study results are mixed 
    • Renal dysfunction (52.7%)
      • Chronic kidney disease is associated with increased mortality with both transcatheter aortic valve replacement and surgical valve replacement 
    • Anemia (48.8%)
      • Evaluation for specific cause, especially underlying malignancy, should be undertaken before valve replacement
      • Preoperative anemia is associated with increased 1-year mortality 
    • Cerebrovascular (30.8%) or peripheral vascular disease (11.6%)
      • Combined surgical approach may be optimal; vascular disease may contraindicate a transfemoral aortic valve implantation
  • Multiple comorbidities, common in older patients, may make it difficult to distinguish an asymptomatic from a symptomatic patient in terms of the relative contribution of aortic valve stenosis to symptoms 

Monitoring

  • Asymptomatic patients in stage B or stage C require routine echocardiographic monitoring to assess progression 
    • Stage B with mild stenosis: every 3 to 5 years
    • Stage B with moderate stenosis: every 1 to 2 years
    • Stage C: every 6 to 12 months
      • If this monitoring recommendation is not followed, all-cause mortality is higher (hazard rate 1.54) and heart failure hospitalization increases (hazard ratio 1.66) 
  • Transthoracic echocardiography is recommended for any change in symptoms or physical examination findings that suggest worsening 
  • For patients on anticoagulant therapy, monitor INR regularly (typically monthly)

Complications

  • Left ventricular hypertrophy and heart failure
  • Pulmonary hypertension
  • Atrial fibrillation
  • Acute coronary syndrome
  • Pulmonary edema
  • Infective endocarditis

Prognosis

  • General
    • Prolonged asymptomatic latent period during which there is progressive anatomic worsening 
      • Average rate of progression is an increase in velocity of 0.3 m/second/year, an increase in mean pressure gradient of 7 mm Hg/year, and a decrease in valve area of 0.1 cm²/year 
      • With onset of angina, syncope, and heart failure, there is a precipitous decline in clinical course and survival 
      • Marked individual variability in rate of change; condition may progress faster in elderly people
    • Results of aortic valve replacement are good overall in most patients, including those undergoing concomitant coronary artery bypass surgery

Screening

Bicuspid aortic valves

  • Screen first-degree relatives of individuals with known bicuspid aortic valves for aortic valve disease 
  • Screening of first-degree relatives is recommended if the patient with bicuspid aortic valve has associated aortopathy or family history of valvular heart disease or aortopathy 

At-risk populations

  • First-degree relatives

Screening tests

  • Echocardiography is used for screening, and should include visualization of the aortic root and ascending aorta

Prevention

  • Treat streptococcal infections promptly and thoroughly to prevent rheumatic heart disease 

References

Lindman BR et al: Aortic valve disease. In: Zipes DP et al, eds: Braunwald’s Heart Disease: A Textbook of Cardiovascular Medicine. 11th ed. Elsevier; 2019:1389-414 Reference

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