Coronary artery bypass graft

Question 1

Which drug is used to prevent clotting during a CABG procedure and how is this reversed?

Answer 1

Heparin - cardiac bypass circuits are thrombogenic
Reversed with protamine sulphate

Question 2

What are the two types of cardiac revascularisation procedures?

Answer 2

CABG - bypass graft
PCI - angioplasty with stenting

Question 3

Define CABG.

Answer 3

Surgial procedure to treat CHD by diverting blood around the stenosed arteries to improve blood flow and oxygen supply to the heart.

Question 4

What are the indications for CABG over PCI?

Answer 4

• CABG preferred for high-risk patients e.g. with left main stem disease or severe 3 vessel disease, severe ventricular dysfunction or DM
• High SYNTAX score
• Failed PCI
• NB: CABG is less likely to need re-intervention

PCI is preferred in:

• 2 vessel disease e.g. right and circumflex
• single vessel disease
• low SYNTAX score/ high mortality STS score

Question 5

What vessels are used for the bypass in CABG?

Question 6

What are the complications of CABG?

Answer 6

• Stroke in 1-2% - higher risk of stroke than PCI
• MI in 1-2%
• AKI
• Ventricular arrhythmias

Question 7

Describe the CABG procedure.

Answer 7

1. Mid-sternal incision
2. Veins from the saphenous vein, rarely arteries (internal mammary) are harvested
3. Heart-lung bypass machine is used *
4. Grafts are attached above and below the stenosis
5. Heart is started using controlled shocks

Off-pump coronary artery bypass surgery (OPCAB) can sometimes be used instead with similar outcomes OR Totally endoscopic robotically assisted coronary artery bypass (TECAB) grafting

Question 8

What are the benefits of CABG?

Answer 8

• Improved angina symptoms, QoL and exercise capacity
• Improved 10yr survival