Key Facts

Aortic regurgitation (AR) is the retrograde flow of blood from the aorta back into the left ventricle during diastole due to failure of the aortic valve to close properly. It may be acute (surgical emergency) or chronic (long compensated period before symptoms develop).

Epidemiology

• Prevalence of moderate-severe AR: ~0.5-1% in population-based studies
• More common in men (~75%)
• Incidence increases with age
• Bicuspid aortic valve: most common cause in younger patients

Aetiology

Valve leaflet disease:

• Bicuspid aortic valve
• Infective endocarditis (leaflet destruction)
• Rheumatic heart disease
• Degenerative calcification
• Myxomatous degeneration

Aortic root disease:

• Aortic root dilatation: Marfan syndrome, Ehlers-Danlos, ankylosing spondylitis
• Aortic dissection (acute AR)
• Syphilitic aortitis (now rare)
• Hypertension

Pathophysiology

Chronic AR:

• Volume overload → LV dilatation (eccentric hypertrophy)
• Increased stroke volume (forward + regurgitant volume)
• Maintained cardiac output for years (compensated phase)
• Eventually, LV dysfunction develops → decompensation → heart failure

Acute AR:

• LV has no time to adapt → sudden volume overload on non-dilated LV
• Dramatic rise in LVEDP → acute pulmonary oedema
• Fall in cardiac output → cardiogenic shock
• Medical emergency requiring urgent surgical intervention

Chronic AR

• Asymptomatic for years (compensated)
• Exertional dyspnoea (first symptom), orthopnoea, PND
• Palpitations (awareness of forceful heartbeat, especially lying on left side)
• Angina (less common than AS)

Acute AR

• Sudden severe dyspnoea, pulmonary oedema
• Cardiogenic shock
• May present with features of underlying cause (e.g., chest pain in dissection, fever in endocarditis)

Examination Findings

• Early diastolic murmur: high-pitched, decrescendo, best heard at left sternal edge with patient sitting forward in expiration
• Collapsing (waterhammer) pulse
• Wide pulse pressure (e.g., 160/40 mmHg)
• Austin Flint murmur: low-pitched mid-diastolic rumble at apex (regurgitant jet hitting anterior mitral leaflet)
• Eponymous signs: de Musset (head bobbing), Quincke (nail bed pulsation), Corrigan (visible carotid pulsation), Duroziez (femoral bruit), Traube (pistol shot femorals)
• Displaced, hyperdynamic apex (volume-loaded LV)

Red Flags

• Acute AR: pulmonary oedema, shock — emergency
• Declining LV function on serial echo
• Increasing LV dimensions (LVESD >50 mm)
• New or worsening symptoms in known chronic AR

Bedside

• ECG: LVH (voltage criteria), left axis deviation; tall R waves in lateral leads
• CXR: cardiomegaly (chronic), pulmonary oedema (acute), aortic root dilatation

Bloods

• BNP/NT-proBNP: elevated in decompensated AR
• Blood cultures: if endocarditis suspected
• FBC, U&Es, CRP: infection screen

Imaging

• Transthoracic echocardiography: severity assessment (vena contracta, regurgitant volume, PHT, EROA), LV dimensions and function, aortic root size
• Transoesophageal echo (TOE): better valve detail, endocarditis assessment, pre-operative
• Cardiac MRI: gold standard for regurgitant fraction quantification, LV volumes
• CT aortography: aortic root assessment, dissection

Special Tests

• Cardiac catheterisation: preoperative coronary assessment
• Serial echocardiography: 6-12 monthly in asymptomatic severe AR to track LV dimensions/function

Non-pharmacological

• Serial echocardiographic monitoring in asymptomatic severe AR (6-12 monthly)
• Moderate exercise generally safe; avoid heavy isometric exercise in severe AR
• Dental hygiene (endocarditis awareness)

Pharmacological

• Vasodilators (nifedipine, ACEi/ARBs): may reduce afterload and slow LV dilatation
  • Used in asymptomatic severe AR when surgery is deferred or contraindicated
  • No robust trial evidence that medical therapy delays need for surgery
• Diuretics: for heart failure symptom management
• Beta-blockers: traditionally avoided in AR (bradycardia prolongs diastole → more regurgitation); may be used cautiously in Marfan syndrome
• Acute AR: IV vasodilators (nitroprusside), inotropes (dobutamine) as bridge to emergency surgery; IABP CONTRAINDICATED (worsens AR)

Surgical/Interventional

• Aortic valve replacement (AVR): definitive treatment
  • Indications: symptomatic severe AR; asymptomatic with LVEF <50% or LVESD >50 mm or LVEDD >70 mm
  • Mechanical vs bioprosthetic choice as per AS
• Aortic root replacement: if aortic root dilatation (Bentall procedure for Marfan)
• Aortic valve repair: increasingly used for selected patients (especially bicuspid valve)
• Acute AR from endocarditis: urgent surgery often needed
• Acute AR from dissection: emergency aortic surgery

Referral Criteria

• Symptomatic severe AR: urgent surgical assessment
• Asymptomatic severe AR with declining LV function or dimensions approaching thresholds: surgical referral
• Acute AR: emergency admission and surgery

• Asymptomatic severe AR with normal LV function: annual mortality ~0.2%; rate of progression to symptoms ~4-6% per year
• Symptomatic severe AR without surgery: 5-year mortality ~25%
• Post-AVR: 10-year survival ~70-80%
• Acute severe AR: high mortality without emergency surgery (~75%)
• LV dysfunction may be partially or fully reversible if surgery performed before irreversible remodelling
• LVEF <50% pre-op: still benefits from surgery but with reduced long-term survival

Eponymous Signs in Aortic Regurgitation

Acute vs Chronic AR Comparison