What are the clinical features of aortic regurgitation?

Clinical Features of Aortic Regurgitation

The key clinical features of aortic regurgitation include wide pulse pressure, diastolic murmur, bounding peripheral pulses, and left ventricular dilation, with progression to heart failure symptoms in advanced cases. 1

Pathophysiology and Classification

Aortic regurgitation (AR) is defined as the backward flow of blood from the aorta into the left ventricle during diastole due to incompetence of the aortic valve 1. It can be classified as:

• Acute AR: Sudden onset, often a medical emergency
• Chronic AR: Gradual progression over years
• Severity: Mild, moderate, or severe based on specific echocardiographic parameters

AR can also be classified based on etiology using the El Khoury functional classification 1:

• Type I: Normal leaflet motion with aortic root dilatation
• Type II: Excessive leaflet motion (prolapse)
• Type III: Restrictive leaflet motion

Clinical Features

Acute Aortic Regurgitation

• Cardiovascular symptoms:

  • Sudden onset heart failure
  • Pulmonary edema
  • Hypotension and cardiogenic shock
  • Tachycardia

• Physical examination:

  • Soft, short diastolic murmur (may be difficult to hear)
  • Absent or diminished peripheral signs typically seen in chronic AR
  • Signs of heart failure (pulmonary rales, S3 gallop)
  • Tachycardia

Chronic Aortic Regurgitation

• Early/Asymptomatic stage:

  • Often asymptomatic for years despite severe regurgitation 2
  • Wide pulse pressure
  • Bounding peripheral pulses (water-hammer pulse)
  • Visible carotid pulsations (Corrigan's pulse)

• Physical examination findings:

  • High-pitched, blowing diastolic murmur at left sternal border
  • Austin Flint murmur (mid-diastolic rumble at apex)
  • Displaced and hyperdynamic apical impulse
  • Pistol-shot sounds over femoral arteries (Traube's sign)
  • Pulsatile nail beds (Quincke's pulse)
  • Systolic hypertension with low diastolic pressure

• Advanced/Symptomatic stage:

  • Exertional dyspnea
  • Orthopnea
  • Paroxysmal nocturnal dyspnea
  • Palpitations
  • Angina-like chest pain
  • Fatigue and reduced exercise tolerance

Diagnostic Features

Electrocardiogram

• Left ventricular hypertrophy
• Left atrial enlargement
• ST-segment and T-wave abnormalities in advanced disease

Chest X-Ray

• Cardiomegaly with left ventricular enlargement
• Boot-shaped heart in severe chronic AR
• Dilated ascending aorta
• Signs of pulmonary congestion in acute AR or decompensated chronic AR

Echocardiography

Echocardiography is the primary diagnostic modality 3, 1 with findings including:

• Markers of severe AR 3:
  • Vena contracta >0.6 cm
  • Regurgitant volume ≥60 mL/beat
  • Effective regurgitant orifice area (EROA) ≥0.3 cm²
  • Holodiastolic flow reversal in descending aorta
  • Doppler jet width ≥65% of LVOT
  • Regurgitant fraction ≥50%
  • Pressure half-time <200 ms
  • Evidence of LV dilation

Advanced Imaging

• Cardiac MRI: Provides accurate assessment of regurgitant fraction and biventricular volumes 1
• CT angiography: Evaluates aortic root dimensions and excludes dissection in acute AR 1

Complications and Natural History

• Progressive left ventricular dilation
• Left ventricular systolic dysfunction
• Heart failure
• Pulmonary hypertension
• Arrhythmias

Without intervention, severe AR is associated with significant morbidity and mortality, with 75% of patients dying or requiring valve replacement within 10 years of diagnosis 1. Even asymptomatic severe AR carries a mortality rate of up to 19% within 6.6 years 1.

Special Considerations

Aortic Regurgitation in Aortic Dissection

Aortic regurgitation may accompany 40-75% of cases with Type A aortic dissection 3. After acute aortic rupture, aortic regurgitation is the second most common cause of death in patients with aortic dissection 3.

Monitoring and Follow-up

Regular monitoring is essential with the following recommended intervals 3, 1:

• Mild AR: Every 3-5 years
• Moderate AR: Every 1-2 years
• Severe asymptomatic AR: Every 6-12 months
• If significant changes in LV size/function occur: Every 3-6 months

Clinical Pitfalls to Avoid

1. Missing the diagnosis of acute AR: The diastolic murmur may be soft and short, making it difficult to detect. Maintain high suspicion in patients with unexplained acute heart failure.

2. Delayed recognition of LV dysfunction: Regular echocardiographic monitoring is essential as symptoms may develop late in the disease course, when irreversible LV damage has already occurred.

3. Overlooking associated aortic pathology: AR may be secondary to aortic root disease or dissection, which requires specific management approaches.

4. Confusing AR with mitral stenosis: The Austin Flint murmur of AR can mimic mitral stenosis, leading to diagnostic errors.

5. Inadequate assessment of AR severity: A comprehensive, multi-parametric approach is required as no single parameter is sufficient to determine AR severity 4.