What are the clinical findings and management of aortic regurgitation (AR)?

Clinical Findings and Management of Aortic Regurgitation (AR)

Aortic regurgitation is characterized by diastolic reflux of blood from the aorta into the left ventricle, with diagnosis primarily confirmed by echocardiography and management determined by symptom status, AR severity, and left ventricular dimensions and function. 1

Clinical Findings

Physical Examination

• Diastolic murmur (key diagnostic finding)
• Exaggerated arterial pulsations
• Low diastolic blood pressure
• Wide pulse pressure
• When diastolic murmur is louder in the right intercostal spaces (3rd and 4th), AR likely results from aortic root dilatation 1
• Peripheral signs are attenuated in acute AR despite poor functional tolerance 1

Diagnostic Testing

1. Echocardiography (primary diagnostic modality):

   • Confirms AR diagnosis when physical examination is equivocal
   • Assesses etiology and valve morphology
   • Quantifies AR severity
   • Evaluates LV dimensions, mass, and systolic function
   • Assesses aortic root size 1, 2

2. Severity Assessment Parameters:

   • Color Doppler: jet width and area
   • Continuous-wave Doppler: rate of decline in regurgitant gradient, holodiastolic flow reversal in descending aorta
   • Quantitative measurements:
     • Vena contracta >0.6 cm
     • Regurgitant volume ≥60 mL/beat
     • Effective regurgitant orifice area (EROA) ≥0.3 cm²
     • Regurgitant fraction ≥50%
     • Pressure half-time <200 ms 2

3. Additional Imaging:

   • Transesophageal echocardiography (TEE): better defines valve and aortic anatomy, especially when valve-sparing intervention is considered
   • Cardiac MRI or CT: evaluates aorta in patients with aortic enlargement, particularly with bicuspid valves or Marfan's syndrome 1
   • Exercise testing: useful for assessing functional capacity in sedentary or patients with equivocal symptoms 1

Etiology

• Aortic root disease (most common cause currently)
• Bicuspid aortic valve (most common congenital risk factor)
• Degenerative valve disease
• Connective tissue disorders (e.g., Marfan syndrome)
• Infective endocarditis
• Failed bioprosthetic valves
• Complications from transcatheter aortic valve interventions 1, 2

Management

Medical Management

1. Acute AR:

   • Medical emergency requiring immediate intervention
   • Vasoactive agents and antibiotics (if endocarditis-related) as bridge to surgery 3

2. Chronic AR:

   • Vasodilator therapy is indicated for:
     • Hypertensive patients with any degree of AR
     • Symptomatic patients with severe AR who have contraindications to surgery
     • Asymptomatic patients with severe AR and LV dilation 1, 2
   • Recommended agents:
     • ACE inhibitors
     • Angiotensin receptor blockers
     • Dihydropyridine calcium channel blockers 2
   • β-blockers should be used with caution due to potential negative effects 3

Monitoring

• Frequency depends on AR severity:
  • Mild AR: every 3-5 years
  • Moderate AR: every 1-2 years
  • Severe asymptomatic AR: every 6-12 months 2

Surgical Intervention

Indications for surgery:

1. Symptomatic severe AR
2. Asymptomatic severe AR with:
   • LVEF <50-55%
   • LVESD >50 mm or >25 mm/m²
   • LVEDD >65 mm
   • Progressive decline in LVEF on serial studies 1, 2

Surgical options:

• Aortic valve repair (when feasible)
• Aortic valve replacement
• Transcatheter interventions (for high-risk surgical patients) 2, 4

Prognosis

• Severe AR is associated with significant cardiovascular morbidity and mortality
• 75% of patients with severe AR die or require valve replacement within 10 years of diagnosis
• Even asymptomatic severe AR carries a mortality rate of up to 19% within 6.6 years 2
• Acute AR has poor prognosis without intervention due to significant increase in LV diastolic pressure 1

Special Considerations

• When AR coexists with aortic stenosis, assessment becomes more challenging and monitoring should occur every 6 months 2
• AR may accompany 40-75% of cases with Type A aortic dissection 2
• Early identification and intervention are crucial to prevent progressive LV dilation, systolic dysfunction, heart failure, pulmonary hypertension, and arrhythmias 2