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Mitral Valve Surgery (MVR)
 
MVR stands for Mitral Valve Repair or Mitral Valve Replacement
 
Repair is preferred to replacement if and where it can be performed
 

 

Indications

  • Mitral valve regurgitation – see details
  • Undergoing another cardiac procedure such as a CABG and there is coexistent mitral valve disease

 

 

Types of Surgery

  • Repair with or without an annuloplasty ring
  • Replacement with preservation of part or al of the mitral apparatus
  • Replacement with removal of the mitral apparatus.
    • not performed unless it is so distorted that it cannot be spared e.g. in Rheumatic heart disease.

 

 

Repair is the operation of choice, if possible, for the following reasons:

  • It preserves native valve
  • No chronic anticoagulaion - except in AF
  • No risk of prosthetic valve failure
  • Better LV funciton anf post-op survival

 

Repair is however more technically demanding.

 

 

Types of Replacement

  • Metallic – largely replaced by prosthetic, bioprosthetic or tissue valves.
  • Prosthetic – widely used. Non-metallic. Bi-leaflet is the valve of choice today.
  • Bioprosthetic – combination of tissue and prosthetic material (PTFE)
  • Tissue – from animal tissue (Xenograft) or from human tissue (heterograft/allograft or autograft)

 

 

  Pre-Operative

  • Proper Dental Care - may need prophylactic antibiotics. A visit to the dentist for check-up, and more if needed, is very common, recommended, and often insisted on by surgeons prior to the operation.
  • Bloods - haemoglobin/anaemia; infection/inflammatory markers; coagulation/clotting; renal function; group and save/crossmatch.
  • Urine dipstick - urine is a good source of bugs that can infect the valve, causing endocarditis - DISASTER!
  • Echocardiogram - to quantify the severity of the disease. Are there any other coexistent abnormalities?
  • Cardiac Catheterisation - to assess coronary arteries for possible revascularisation.

 

 

 Alternatives to Repair or Replacement

  • Pharmacotherapy - no effective medical treatment  it is a structural disease. Useful in improving forward cadiac output
  • Percutaneous Aortic Valve Replacement – used mostly for patients unable to tolerate surgery.
  • Mitral valvulotomy

 

 

Challenges of Mitral Valve Surgery

  • The Asymptomatic Patient (especially those with normal LV function) -
    • There are risks to every operation. Mortality is significant even for isoloted MVR
    • Even if the patient undergoes a repair procedure one must remember that there are the following risks
      • Re-operation
      • A failed repair procedure almost certainly means a replacement which then has very high risks - it becomes a second operation, much sooner than expected, and anticoagulation. Hence, prophylactic surgery in asymptomatic with norma LV function must have a high likelihood of successful repair.
  • The very sick patient - mitral valve disease with such advanced LV dysfunction that he or she is no longer a candidate for surgery. It is essential to distinguish a cardiomyopathy with secondary mitral regurgitation from primary mitral regurgitation with secondary myocardial dysfunction. In the latter, mitral regurgitation is likely to improve symptoms and prevent further deterioration.
  • Anticoagulation 

 

References

  • Oxford Handbook of Cardiothoracic Surgery. Chikwe, Beddow, Glenville, 2006
  • Cardiac Surgery in the Adult. Lawrence Cohn, 2008
  • ACC/AHA 2006 Guidelines for the Management of Patients with Valvular Heart Disease. J. Am Coll. Cardiol. 2006; 48;e1-e148