What is the preferred source of vein grafts for Coronary Artery Bypass Grafting (CABG) in adult patients with coronary artery disease?

Preferred Vein Graft Sources for CABG

The saphenous vein remains the standard venous conduit for CABG when venous grafting is necessary, though arterial grafts should be strongly preferred whenever feasible due to superior long-term patency. 1, 2

Primary Conduit Strategy: Prioritize Arterial Grafts

The fundamental principle is to minimize or eliminate the use of venous conduits entirely by maximizing arterial grafting:

• Left internal mammary artery (LIMA) to LAD is mandatory - this is a Class I recommendation with >90% patency at 10-15 years versus only 25-50% for saphenous vein grafts at the same timepoint 2, 3

• Radial artery is recommended over saphenous vein for the second most important non-LAD vessel (Class I, Level B-R) - demonstrating 89% patency at 4-5 years compared to 65-80% for saphenous vein 1, 2

• Bilateral internal mammary artery (BIMA) grafting should be strongly considered in younger patients and those without high risk of sternal complications (Class 2a recommendation) 2, 3

When Venous Grafts Are Necessary

Saphenous Vein Selection

The great saphenous vein (GSV) is the venous conduit of choice when arterial grafts are insufficient or contraindicated 4, 5, 6:

• GSV has been used since the inception of CABG and remains the most frequently employed venous conduit 4
• It provides adequate length and diameter for most coronary targets 5

Specific Indications for Saphenous Vein Use

Use saphenous vein grafts preferentially in these scenarios:

• Right coronary artery grafting with <90% stenosis where competitive flow makes arterial grafts less ideal 5
• Octogenarians where the longevity advantage of arterial grafts may not be realized 5
• Patients at very high risk of sternal wound infections where BIMA is contraindicated 5
• When insufficient arterial conduits are available for complete revascularization 6

Critical Technical Considerations for Saphenous Vein Harvesting

Harvesting Technique Matters Significantly

Use no-touch or conventional open harvesting techniques rather than endoscopic harvesting when saphenous vein must be used:

• Endoscopic vein harvesting (EVH) has been associated with vein graft failure and adverse clinical outcomes 2, 3
• No-touch technique preserves the vein's surrounding tissue and may improve patency 7
• EVH does reduce wound complications (91% reduction in wound infection versus no-touch, 77% versus conventional) but at the cost of graft quality 7

Graft Configuration

Avoid multiple distal targets (sequential grafts) with saphenous vein when possible:

• Saphenous vein grafts with multiple distal targets (m-SVG) show higher 1-year failure rates compared to single distal targets (adjusted OR 1.24,95% CI 1.03-1.48) 8
• At 5 years, m-SVG patients have significantly higher rates of death or MI (HR 1.21,95% CI 1.03-1.43) 8
• Use single distal target grafts (s-SVG) whenever feasible 8

Patency Expectations and Clinical Reality

Understanding the limitations of venous grafts is essential:

• Early failure is common: 10-26% of saphenous vein grafts fail between 12-18 months, particularly for distal targets and severely diseased small vessels 3
• Progressive attrition: Patency declines from >90% at 1 year to 65-80% at 4-5 years to only 25-50% at 10-15 years 2, 3
• Vein graft disease affects 40-50% of patients by 10 years after surgery 6

Common Pitfalls to Avoid

• Do not use radial artery after transradial catheterization - the vessel may be damaged 1
• Avoid radial artery in patients with chronic kidney disease likely to progress rapidly to hemodialysis (preserves access sites) 1
• Assess palmar arch completeness objectively before radial artery harvest using Allen's test or Doppler 1, 2
• Target radial artery grafts to vessels with significant stenosis (>70% for left-sided, >90% for right-sided coronaries) 2

Algorithm for Conduit Selection

1. First priority: LIMA to LAD (mandatory unless contraindicated) 2, 3
2. Second priority: Radial artery to second most important vessel with significant stenosis 1, 2
3. Third priority: Consider BIMA if patient is young (<60 years), experienced surgeon, and low sternal infection risk 2, 3
4. Fourth priority: Right internal mammary artery or gastroepiploic artery for additional arterial grafts if appropriate 1
5. Final option: Saphenous vein grafts using no-touch or conventional open technique for remaining targets, preferentially as single distal target grafts 2, 7, 8

The overarching principle is complete arterial revascularization when possible, particularly in patients ≤60 years with few comorbidities, reserving saphenous vein grafts only when arterial options are exhausted or specifically indicated 2, 3.