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Valve replacements

Clinical examination

  • Metallic valves
    • Metallic mitral valve: S1 sounds metallic
    • Metallic aortic valve: S2 sounds metallic 
    • There is often a click audible without a stethoscope
  • Tissue valves
    • Relevant heart sounds may be normal, loud or quiet
  • Systolic flow murmurs are normal for aortic valve replacements
  • Assess for valve function (signs of regurgitation of replaced valve), cardiac decompensation (signs of heart failure), and signs of infective endocarditis
  • Also look for signs of over-anticoagulation (bruising) and anaemia (haemolysis)

Metallic mitral valve

Indications for surgery

Indications in left-sided valve dysfunction

  • Any valve: associated LVF, symptomatic
  • If regurgitation, also: acute onset, associated LV dilation
  • If mitral, also: presence of pulmonary hypertension

NB: for MR, valve repair is preferred when possible; for MS, balloon valvuloplasty is preferred unless contraindicated (i.e. coexistent MR, thrombus or calcified valve).

Indications in infective endocarditis

  • Associated heart failure 
  • Uncontrolled infection (fistula, enlarging vegetation, false aneurysm, aortic root abscess, persistently positive blood cultures, fungal/multidrug-resistant organism)
  • High embolic risk (persistent large vegetation)

NB: If prosthetic valve, surgery also indicated if: <2 months post-op, valve dysfunction or Staphylococcus aureus infection.

Detail about valve types

Tissue valve

  • Usually porcine xenograft
  • Needs replacing after 10-15 years; sooner if patient is active
  • No need for warfarin
  • Recommended for older people, people with low life expectancy and females of child-bearing age

Mechanical valve

  • Longer lasting (older valves 20-30 years, newer valves >30 years)
  • Lifelong warfarin 
  • Makes a quiet clicking noise
  • Recommended for younger people (<60 years) so they don’t need repeat surgeries (unless female and of child-bearing age because warfarin is teratogenic) 

Procedure

  • Pre-operative: transthoracic Β± transoesophageal echo, coronary angiography 
  • May be performed by:
    • Open surgery: via midline sternotomy
    • Minimally invasive surgery
      • Aortic valve: via right anterior mini-thoracotomy (2nd intercostal space) or mini-sternotomy
      • Mitral valve: via right lateral mini-thoracotomy (below nipple or in breast crease)
  • Patient is put on cardiopulmonary bypass while valve is replaced
  • If there is also coronary artery disease, CABG is usually performed concurrently – check the legs for a vein grafting scar
Thoracic scars

Questions

Please list some complications of valve replacements?

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Which bacteria commonly cause infective endocarditis?

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What is a TAVI and when may this be indicated?

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Try some OSCE stations

  1. Metallic aortic valve
  2. Metallic mitral valve
  3. More stations can be found here!

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