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Home | Viva | Operative Surgery | Cardiothoracic Surgery

Coronary Artery Bypass Graft Surgery (CABG)

Operative Technique

Surgical Anatomy of the Heart

Access to heart

  • Harvesting of Long saphenous vein
  • chest opened via sternotomy + LIMA dissected from chest wall
  • Heart cannulated via ascending aorta + right atrium before cardiopulmonary
  • Longitudinal arteriotomy made beyond narrowing of coronary vessel + distal anastamosis is performed
  • Application of aortic cross clamping prevents blood flow down coronary arteries (but increases risk of ischaemia)
  • Patient re-warmed, clamps removed, heart re-perfused

Selection of Conduit

  • Venous Grafts:
    • Long saphenous vein (10 year patency rate 50-60%)
    • short saphenous vein
    • cephalic vein
  • Arterial Grafts:
    • Left internal mammary artery (internal thoracic artery) - conduit of choice for LAD (10 year patency rate 90%)
    • Radial artery -NB Allen's test to ascertain collateral circulation

Pre-operative workup

  • ECG
  • Echocardiography
  • Carotid duplex study
  • Pulmonary function tests
  • Angiography
  • FBC, U+Es, LFTs, Clotting, G+S

  • Antibiotics: Cefuroxime 1.5g +/- Vancomycin

Post-op management

  • Prophylactic chest drain
  • External cardiac pacing

Complications

Bleeding
3-5% of patients.
May develop tamponade / hypotension
Medical management first
May require emergency re-sternotomy

Management of Bleeding:

Check coagulation profile
Fibrinogen
Platelets

Specific treatments:

  1. Protamine sulphate
    • Directly binds to heparin and inactivates
  2. Trasylol / Aprotin 2MU iv
    • (Bovine) serine protease inhibitor (specifically trypsin, chymotrypsin, plasmin, kallikrein)
    • Effect on Kallikrein: inhibits formation of factor XIIa and plasmin - slows down fibrinolysis
  3. Tranexamic acid
    • Inhibits activation of plasminogen into plasmin

Arrythmias
Common to develop ST / AF

Management of Tachyarrythmias

  1. Correct potassium >4.5mmol/l - Potassium chloride
  2. Correct magnesium: 8/10-20mmol MgSO4 IV

Atrial Flutter

  1. Vagal manoeuvres
  2. Adenosine 6mg/12mg/12mg
  3. B-blocker rate control
  4. DC synchronised cardioversion

Atrial Fibrillation

  1. B-blocker iv / Digoxin 500mg iv/12'
  2. Amiodarone 300mg iv/1' + 900mg iv/23'
  3. DC synchronised cardioversion

Management of Bradyarrythmias

  1. Atropine 500mcg iv bolus (repeat to maximum of 3mg)
  2. Adrenaline 2-10mcg/min
  3. Cardiac pacing

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