Aortic regurgitation

• Overview:

  • Results from an incompetent aortic valve causing regurgitant flow of blood in diastole
  • Tends to present between the 4th and 6th decades of life
  • More common in males
  • Most common causes are degenerative disease and congenital bicuspid valve
• Causes of aortic regurgitation can be split into either:

  • Primary disease of the aortic valve leaflets
  • Dilation of the aortic root
• Disease of the valve leaflets:

  • Rheumatic heart disease - streptococcal (group A) infection
  • Congenital - bicuspid valve (most common cause)
  • Degenerative - calcification (most common cause)
  • Endocarditis - vegetations may cause flailing of the valve leaflets (strep. viridans, staph. aureus, enterococci)
• Dilation of the aortic root:

  • Connective tissue disorders e.g. Marfan's syndrome, Ehlers-Danlos syndrome
  • Aortitis - inflammation of the aortic root - associated with RA, ankylosing spondylitis, giant cell arteritis
  • Aortic dissection - Stanford A dissections
• Acute aortic regurgitation:

  • Medical emergency - results in pulmonary oedema and cardiogenic shock
  • Regurgitation of blood during diastole causes an increase in the left ventricular end-diastolic volume and pressure = reduced coronary flow (fill predominantly during diastole) and increased end-diastolic pressure (pulmonary oedema and dyspnoea)
  • Causes - infective endocarditis, rheumatic fever, aortic dissection
• Patients may present acutely with features of heart failure in acute AR or have a prolonged period of little to no symptoms followed by gradual onset of symptoms in chronic disease.
• Clinical features:

  • Decrescendo early diastolic murmur
  • Heart loudest at the left sternal edge (the direction that the turbulent blood flows), sometimes heard loudest over the aortic area
  • Collapsing pulse - a water hammer pulse with wide pulse pressure
  • Displaced hyperdynamic apex beat
• Austin flint murmur:

  • Sign of severe aortic regurgitation
  • Low-pitched, rumbling, mid-diastolic murmur
  • Heard best at the apex
  • Caused by the regurgitated blood through the aortic valve mixing with blood from the left atrium during atrial contraction
• Eponymous clinical signs:

  • Corrigan's sign - visible distention and collapse of carotid arteries
  • Dr Musset's sign - head bobbing with each heartbeat
  • Quincke's sign - pulsations are seen in the nail bed with each heartbeat when the nail bed is lightly compressed
  • Traube's sign - 'pistol shot' sound heard when stethoscope placed over the femoral artery during systole and diastole
  • Muller's sign - uvula pulsations with each heartbeat
• Investigations:

  • ECG - left ventricular hypertrophy
  • Diagnostic investigation = TTE/TOE
  • CXR - signs of heart failure - most commonly cardiomegaly
  • Angiography - needed in patients with chronic AR prior to surgery
• Management:

  • Acute AR = emergency valve replacement
  • Valve replacement - mechanical valve or bioprosthetic valve
• Mechanical valve:

  • require long-term anticoagulation
  • long lifespan reducing the need for a second operation
  • Suited to younger patients.
• Bioprosthetic valve:

  • no need for long-term anticoagulation
  • limited life span (around 10 years) and a repeat operation is more likely.
  • Suited to older patients.