Preferred Vein Sources for CABG
The saphenous vein remains the most commonly used venous conduit for CABG, though arterial grafts (radial artery, internal mammary arteries) are strongly preferred when available. 1, 2
Primary Conduit Hierarchy
First Choice: Arterial Conduits
- Left internal mammary artery (LIMA) to the LAD is mandatory and represents the gold standard with >90% patency at 10-15 years 1, 2, 3
- Radial artery is recommended over saphenous vein for the second most important non-LAD vessel (Class I, Level B-R recommendation) with superior patency rates of 89% versus 65-80% at 4-5 years 1, 2, 3
- Bilateral internal mammary arteries (BIMA) should be considered in younger patients with few comorbidities for additional survival benefit 2, 4, 3
When Venous Conduits Are Needed: Saphenous Vein Sources
Greater saphenous vein is the primary venous conduit when arterial grafts are insufficient or unavailable 1, 5
Acceptable venous alternatives when ipsilateral greater saphenous vein is unsuitable:
- Lesser saphenous vein 1
- Contralateral greater saphenous vein 1
- Arm veins 1
- Spliced veins (composite grafts) 1
Harvesting Technique Considerations
Endoscopic vs. Open Harvesting
Use endoscopic saphenous vein harvest technique in patients at risk of wound complications to reduce leg wound infection rates from 20-26% to 4-7% 1, 6, 7, 8
However, use no-touch saphenous vein harvest technique in patients at low risk of wound complications 1, as endoscopic harvesting has been associated with reduced long-term graft patency 4, 8
Clinical Situations Favoring Saphenous Vein Over Additional Arterial Grafts
Saphenous vein grafting should be considered instead of arterial grafts in:
- Right coronary artery grafting with <90% stenosis (higher competitive flow) 4, 5
- Patients at very high risk of sternal wound infections 5
- Octogenarians 5
- Patients with chronic kidney disease likely to progress to hemodialysis (preserve radial arteries for dialysis access) 1, 2
Important Technical Caveats
For Radial Artery Use:
- Objectively assess palmar arch completeness and ulnar compensation before harvesting 1, 2
- Avoid radial artery after transradial catheterization 1, 2
- Use radial artery grafts only for vessels with significant stenosis (>70% left-sided, >90% right-sided) 2, 3
- Prescribe oral calcium channel blockers for the first postoperative year to prevent vasospasm 1, 2
For Saphenous Vein Grafts:
- Accept declining patency rates: >90% at 1 year, 65-80% at 4-5 years, only 25-50% at 10-15 years 4, 3
- Use skeletonized harvesting technique when possible 1
- Consider composite sequential grafting (prosthetic to above-knee popliteal, then vein jump graft distally) when vein length is inadequate 1
Prosthetic Grafts: Last Resort Only
Prosthetic material (PTFE, polyester) can be used for above-knee popliteal bypasses when no autogenous vein is available, but patency is significantly inferior (47% at 5 years for above-knee, 33% for below-knee) 1. Avoid prosthetic grafts for coronary bypass—exhaust all venous options first.