Aortic Valve Repair/Replacement

Airway: ETT
Access: 14G IVC or MAC line, arterial line, CVC, +/- PAC
Pain: Substantial, especially in younger patients
Position: Supine/crucifix
Time: 3-4 hours
Blood loss: G+H required. Cross-match if re-do surgery, anaemic, small, sick, or emergency.
Special: CPB - higher risk for anaesthetic awareness

Intervention on the aortic valve is performed for:

• Stenosis
  Not amenable to repair.
• Regurgitation
• Stenosis/Regurgitation
• Endocarditis

Surgical techniques include:

• Replacement
  Typical, and may be performed with:
  • Bioprosthetic valves
    • Porcine or bovine
    • Do not require anticoagulation
    • Do not last as long as mechanical valves
  • Mechanical valves
    • Require anticoagulation
    • Last longer than bioprosthetic valves
  • Homografts
    Rarely available.
• Repair
  Appropriate for isolated regurgitation, with or without associated aneurysm. Technique will depend on:
  • Cause of regurgitation
    Defect of the the:
    • STJ
      Supracoronary replacement of ascending aorta with prosthesis.
    • Annulus
      Multiple techniques:
      • Annuloplasty ring
        May be:
        • Extraaortic
        • Intraaortic
      • Plegeted sutures
        Rarely permits complete stability of annulus.
    • Leaflets
      Amenability to repair depends on valve morphology; particularly the ability to achieve an effective relationship between the:
      • Effective height
        Height from annulus to leaflet tip.
      • Geometric height
        Length of the valve leaflet.
      • Coaptation height
        Height of leaflet contact during diastole.

Considerations

This covers factors unique to AVR. Factors relating to cardiac surgery in general are covered here.

• B
  • Left heart failure
• C
  • LVH
    
    • Often occurs secondary to AS
    • ↑ importance of good myocardial protection on CPB

Preparation

This covers factors unique to AVR. Factors relating to cardiac surgery in general are covered here.

Induction

• Haemodynamically stable induction is vital
  • Consider vasopressor infusion in critical AS.
  • Filling is important in AS and beneficial in AR

Intraoperative

Surgical Stages

• Median sternotomy
• Bicaval and aortic cannulation
• Establishement of CPB
• LV drained via PA
• Cardioplegia administered
• Aorta opened and existing valve excised and annulus debrided
• Annulus measured and valvular prostehesis sutured in place
  Rewarming during final stages of valvular implantation.
• Filing of the LV during aortic closure
• Left heart de-aired in the head down position
• Decannulation and reversal of heparinisation

Postoperative

Aortic Stenosis:

• The rapid ↓ in AV gradient leads to rapid ↓ in PCWP and LVEDP, and ↑ in SV
• Myocardial function typically improves rapidly
• Diastolic dysfunction persists
  Remain very preload and afterload dependent until LV reverse remodelling completes.

Aortic Regurgitation:

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References

1. Vojáček J, Žáček P, Dominik J. Aortic valve repair and valve sparing procedures. Cor et Vasa. 2017;59(1):e77-e84. doi:10.1016/j.crvasa.2017.01.025