Aortic regurgitation

Aortic regurgitation (AR) is a valvular heart disease characterized by incomplete closure of the aortic valve leading to the reflux of blood from the aorta into the left ventricle (LV) during diastole. Aortic regurgitation can be acute (primarily caused by bacterial endocarditis or aortic dissection) or chronic (e.g., due to a congenital bicuspid valve or rheumatic fever) and may be caused by a valvular defect or an abnormality of the aorta. In most cases, acute AR leads to rapid deterioration of LV function with subsequent pulmonary edema and cardiac decompensation. Chronic AR may remain compensated for a long period of time, becoming symptomatic only when left heart failure develops. Auscultation reveals an S₃ and a high-pitched, decrescendo early diastolic murmur. Another characteristic diagnostic finding is widened pulse pressure. Echocardiography is the most important diagnostic tool, both for confirming the diagnosis and determining the severity of disease. In asymptomatic patients, conservative treatment consists of symptom management and physical activity as tolerated. Symptomatic patients or those with severely reduced LV function require surgical intervention, most commonly aortic valve replacement.

Acute aortic regurgitation ^[1][2]

• Infective endocarditis
• Aortic dissection (ascending aorta)
• Chest trauma
• Iatrogenic complications

Chronic aortic regurgitation ^[1][3]

• Primary valvular defect
  • Congenital bicuspid aortic valve: most common cause of AR in young adults in high-income countries
  • Calcific aortic valve disease: most common cause of AR in older patients in high-income countries ^[1][3]
  • Rheumatic heart disease: most common cause of AR in lower-income countries ^[4]
• Aortic dilatation
  • Connective tissue disorders (e.g., Marfan syndrome, Ehlers-Danlos syndrome)
  • Chronic hypertension
  • Aortitis of any etiology (e.g., tertiary syphilis)
  • Thoracic aortic aneurysm

American Heart Association (AHA)/American College of Cardiology (ACC) staging system for chronic AR ^[5]

Staging is based on echocardiographic criteria and the presence of symptoms.

• General
  • Regurgitation of blood from the aorta into the left ventricle (LV) leads to:
    • Increased systolic blood pressure and decreased diastolic pressure
    • Widened pulse pressure → water hammer pulse (see “Diagnostics” below)
• Acute AR
  • Because LV cannot sufficiently dilate in response to regurgitant blood, LV end-diastolic pressure increases rapidly → pressure transmits backwards into pulmonary circulation → pulmonary edema and dyspnea
  • Decreased cardiac output if severe → cardiogenic shock and myocardial ischemia
• Chronic AR
  • Initially, a compensatory increase in stroke volume can maintain adequate cardiac output despite regurgitation (compensated heart failure)
  • Over time, increased left ventricular end-diastolic volume → LV enlargement and eccentric hypertrophy of myocardium → left ventricular systolic dysfunction → decompensated heart failure

References:^[6]

Acute aortic regurgitation ^[2][7]

Signs and symptoms

• Sudden, severe dyspnea
• Rapid cardiac decompensation secondary to heart failure
• Pulmonary edema
• Symptoms related to underlying disease (e.g., fever due to endocarditis, chest pain due to aortic dissection)

Auscultation

• Soft S₁
• Soft and short early diastolic murmur

Chronic aortic regurgitation ^[2]

Signs and symptoms

• May be asymptomatic for up to decades despite progressive LV dilation
• Palpitations
• Symptoms of high pulse pressure
  • Water hammer pulse of peripheral arteries characterized by rapid upstroke and downstroke
  • Corrigan pulse: pulse of carotid arteries characterized by rapid upstroke and downstroke
  • Traube sign: pistol shot-like sounds heard over the femoral artery on auscultation
  • Duroziez sign: to-and-fro bruit over the femoral artery that is heard when slight pressure is applied with a stethoscope
  • Quincke sign: visible capillary pulse when pressure is applied to the tip of a fingernail
  • De Musset sign: rhythmic nodding or bobbing of the head in synchrony with heartbeats
• Symptoms of left heart failure
  • Exertional dyspnea
  • Angina
  • Orthopnea
  • Easy fatigability
  • Syncope
• Point of maximal impulse (PMI): diffuse, hyperdynamic, and displaced inferolaterally

Auscultation

• S₃
• High-pitched, blowing, decrescendo early diastolic murmur
  • AR due to valvular disease: heard best in the left third and fourth intercostal spaces and along the left sternal border (Erb point)
  • AR due to aortic root disease (e.g., aortic dissection): heard best along the right sternal border
  • Worsens with squatting and handgrip
• Austin Flint murmur
  • Rumbling, low-pitched, middiastolic or presystolic murmur heard best at the apex
  • Caused by regurgitant blood striking the anterior leaflet of the mitral valve, which leads to premature closure of the mitral leaflets
• In more severe stages, possibly a harsh, crescendo-decrescendo midsystolic murmur that resembles the ejection murmur heard in aortic stenosis
• See also “Auscultation in valvular defects.”

Approach

• Transthoracic echocardiography (TTE) is the primary diagnostic tool to diagnose AR and assess the severity of disease.
• Acute AR is an emergency that must be diagnosed and treated immediately.
  • CTA Chest (or TEE) is the preferred diagnostic tool if aortic dissection is suspected.
  • Additional diagnostics depend on patient stability and the suspected underlying condition (e.g., blood cultures for endocarditis).
• In chronic AR, TEE, CMR, or cardiac catheterization can be used to confirm the diagnosis if TTE findings are inconclusive.

Initial evaluation

Echocardiography ^[5][8]

• Indication: assessment of aortic valve structure and function, cause and severity of regurgitation, the left ventricle and other heart valves ^[2]
  • TTE: modality of choice for initial assessment of all patients with suspected AR
  • TEE ^[5]
    • Moderate to severe AR, if TTE findings are equivocal
    • Preoperative planning
    • Acute AR with suspected aortic dissection
• Supportive findings ^[3]
  • General findings
    • Abnormal aortic valve leaflets
    • Fluttering of the anterior mitral valve leaflet ^[2][3]
    • Regurgitant AR jet on Doppler flow tracing
    • Dilated aorta ^[9]
  • Findings specific to acute AR ^[7]
    • Reduced cardiac output
    • Elevated end-diastolic left ventricular pressure
    • Early mitral valve closing
    • Rapid equilibration of aortic and left ventricular pressure
  • Findings specific to chronic AR: increased LV size and volume ^[2]

Other ^[5]

• Laboratory studies: not routinely indicated but useful for the evaluation of other causes of symptoms (see also “Diagnostics” in the “Dyspnea” and “Chest pain” articles)
  • Blood cultures: in suspected infective endocarditis (at least three sets) ^[10]
  • BNP/NT-proBNP ^[11][12]
• ECG: nonspecific; helps rule out differential diagnoses (e.g., ACS, cardiac arrhythmia)
  • Acute AR: possible signs of the underlying cause (e.g., signs of myocardial ischemia in aortic dissection)
  • Chronic AR
    • ECG signs of LVH
    • ST-segment depression and T-wave inversion in I, aVL, V₅, and V₆^[2]
• Chest x-ray: used to assess for pulmonary edema and rule out other causes of acute dyspnea
  • Acute AR ^[1]
    • Normal heart silhouette
    • X-ray signs of pulmonary congestion or edema
  • Chronic AR ^[2]
    • X-ray signs of LVH
    • Enlarged cardiac silhouette
  • Chronic AR or acute AR caused by aortic dissection: possible prominent aortic root/arch ^[13][14]

Additional evaluation ^[5]

Advanced imaging

• Cardiac MRI ^[2][8]
  • Indication: moderate to severe AR (AR stage B–AR stage D) with inadequate echocardiographic imaging or a discrepancy between clinical presentation and echocardiographic findings
  • Objective: precise evaluation of anatomy and hemodynamics
• CTA chest
  • Acute AR: indicated especially if aortic dissection is suspected
  • Chronic AR: not routinely recommended

Cardiac catheterization

• Diagnostic hemodynamic cardiac catheterization with aortography
  • Indication: moderate to severe AR (AR stage B–AR stage D) with inadequate echocardiographic imaging or a discrepancy between clinical presentation and echocardiographic findings
  • Objective: hemodynamic evaluation (e.g., severity of regurgitation, intracardiac pressures, cardiac function)
• Coronary angiography
  • Indications: preoperative cardiac risk stratification in patients with angina, reduced LVEF, signs of ischemia, or coronary risk factors
  • Findings: signs of CAD (e.g., coronary stenosis)

Exercise stress testing

• Indication: may be used to provoke possible exertional symptoms or assess fitness in patients with severe AR
• Findings: symptoms of aortic regurgitation (e.g., dyspnea, angina)

Approach ^[2][5]

• Acute aortic regurgitation
  • Severe acute AR requires surgical treatment as soon as possible. ^[3][15]
  • Consult cardiology and cardiothoracic surgery immediately.
  • Medical management of complications (e.g., pulmonary edema) should not delay definitive treatment.
  • Identify and treat the underlying cause (see, e.g., “Treatment” in “Infective endocarditis” and “Aortic dissection” articles).
• Chronic aortic regurgitation
  • Surgery is the mainstay of treatment for symptomatic AR and severe asymptomatic AR.
  • Optimize medical management of comorbidities (e.g., heart failure treatment), especially if surgery is contraindicated.

All patients with acute severe aortic regurgitation should undergo urgent surgical treatment. ^[2]

IABP increases regurgitated volume and is contraindicated in acute severe AR. ^[5]

Surgical management ^[5]

The choice of procedure depends on the cause of the valve defect and comorbidities. All patients with severe aortic regurgitation being considered for intervention should be evaluated by members of a heart valve team if feasible.

• Indications ^[5][16]
  • Acute severe AR
  • Symptomatic chronic severe AR (AR stage D)
  • Asymptomatic chronic severe AR (AR stage C) with one of the following:
    • Reduced LVEF ≤ 55%
    • Consider if LVESD > 50 mm
    • Cardiac surgery for other indications
• Surgical aortic valve replacement: Standard procedure for acute and chronic AR (see “Prosthetic heart valve” for details) ^[3]
• Alternative procedures ^[2]
  • Valve-sparing repair of aortic sinuses and ascending aorta : may be considered if AR is caused by aortic dilatation and the valve itself is unimpaired
  • Primary valve repair: not routinely performed, but may be considered in isolated minor leaflet damage ^[2]
  • Transcatheter aortic valve replacement: not recommended for treatment of isolated AR
• Follow-up
  • Complications of aortic valve replacement include arrhythmias, endocarditis, and thromboembolism
  • Antithrombotic therapy for patients with prosthetic aortic valves depends on the choice of valve replacement (mechanical or bioprosthetic) and risk factors.

Medical management ^[5]

Acute aortic regurgitation ^[3][15]

• Medical management is focused on stabilizing hemodynamics prior to surgery, e.g., via:
  • Management of cardiogenic shock with inoconstrictors or inodilators (e.g., dobutamine or dopamine)
  • Afterload reduction with vasodilators for acute heart failure (e.g., nitroprusside)
• Beta blockers may be indicated in aortic dissection; avoid in other causes of acute AR. ^[5]

Avoid beta blockers in acute AR, unless due to aortic dissection. ^[5]

Chronic aortic regurgitation

All patients should be screened and treated for other cardiac risk factors. No medical treatments are known to influence the progression of the disease. ^[17]

• Hypertension
  • Initiate treatment if systolic blood pressure is > 140 mm Hg and follow standard hypertension guidelines.
  • Vasodilators (e.g., ACE inhibitors, ARBs) may be preferable to beta blockers. ^[17]
• Heart failure: : Manage according to guideline recommendations (see “Treatment of heart failure”).
• Prophylactic antibiotics
  • At-risk patients, e.g., with prosthetic valves or a history of infective endocarditis: Consider antibiotic prophylaxis prior to certain dental procedures (see “Prophylaxis for endocarditis”). ^[6]
  • Rheumatic heart disease: long-term secondary prophylaxis (see “Prevention” in “Rheumatic fever” for details) ^[18]

Monitoring ^[5]

• Serial echocardiography: Regular follow-up imaging is indicated for asymptomatic patients to identify possible progression and indications for intervention.
  • Mild regurgitation (AR stage B): every 3–5 years
  • Moderate regurgitation (AR stage B): every 1–2 years
  • AR stage C1 regurgitation: every 6–12 months
  • On-demand imaging is indicated for patients with any change in signs or symptoms.

• Perform ABCDE assessment.
• Initiate afterload reduction as needed with vasodilators for acute heart failure.
• Initiate inotropic support as needed; see “Management of cardiogenic shock.”
• Confirm diagnosis with TTE.
• Consult cardiology and cardiothoracic surgery for definitive management.
• Obtain CTA chest or TEE if aortic dissection is suspected.
• Initiate emergency preoperative evaluation.
• Transfer to OR or ICU.

• Asymptomatic patients with normal LVEF: progression to symptoms or LV dysfunction at a rate of < 6% per year ^[19]
• Asymptomatic patients with decreased EF: progression to symptoms at a rate of > 25% per year ^[19]
• Symptomatic patients: mortality rate is > 10% per year ^[1][19]