Coronary artery bypass grafting
Grafts carry blood around blocked coronary arteries to the heart muscle beyond them.
Why it's done
- Left main stem disease.
- Three-vessel disease, especially with diabetes or reduced left ventricular function.
- Disease involving the proximal LAD when PCI is unsuitable.
- The choice between CABG and PCI is made by the heart team (surgeon, cardiologist and others), often using the SYNTAX score.
The steps
- Open and harvest: Median sternotomy. The left internal mammary artery (LIMA) is taken down from the chest wall while a second team harvests the long saphenous vein or radial artery, often endoscopically.
- Bypass or not: Most CABG is done on bypass with an arrested heart. Off-pump CABG (OPCAB) uses a stabiliser to hold a small area of the beating heart still instead.
- Distal anastomoses: Each graft is sewn onto the coronary artery beyond the blockage using very fine polypropylene (often 7-0 or 8-0).
- LIMA to LAD: The LIMA is almost always sewn to the left anterior descending artery. It stays attached to the subclavian artery at its origin, so it's an 'in situ' graft.
- Proximal anastomoses: Vein and radial grafts are sewn onto the ascending aorta to give them inflow.
- Check and close: Graft flow is often measured with transit-time flow probes. Pacing wires and chest drains go in, and the sternum is closed with steel wires.
Risks
- In-hospital mortality around 1–2% for elective isolated CABG (higher with age, poor LV function, urgency)
- Stroke around 1–2%
- New atrial fibrillation in roughly a quarter to a third of patients
- Bleeding needing a return to theatre
- Sternal wound infection, more likely with diabetes, obesity and bilateral mammary harvest
- Acute kidney injury
Recovery
Usually a night on intensive care, home around day 5–8. The sternum takes roughly 6–12 weeks to heal, so no heavy lifting. UK DVLA guidance for car drivers is no driving for 4 weeks after CABG. Cardiac rehab, aspirin and a statin follow for life.
St George's Cardiothoracic Surgery Society, City St George's, University of London.