What is the most commonly used conduit for a radial artery graft?

Radial Artery as the Most Commonly Used Conduit for CABG After the LIMA

The radial artery is the most commonly used arterial conduit for coronary artery bypass grafting (CABG) after the left internal mammary artery (LIMA), and is specifically recommended to graft the second most important, significantly stenosed, non-LAD vessel to improve long-term cardiac outcomes. 1

Evidence Supporting Radial Artery Use

• The American College of Cardiology/American Heart Association (ACC/AHA) guidelines give a Class 1, Level B-R recommendation for using the radial artery in preference to saphenous vein conduits for grafting the second most important non-LAD vessel 1
• Several randomized trials and meta-analyses have demonstrated better mid- and long-term patency rates for the radial artery compared to saphenous vein grafts 1
• A pooled analysis of 6 randomized trials showed improved clinical outcomes regarding adverse cardiac events at 5 and 10 years after surgery when the radial artery was used instead of saphenous vein grafts 1
• 20-year follow-up studies show radial artery patency rates of 84.8%, which is significantly better than saphenous vein grafts (45% patency) and not statistically inferior to internal thoracic artery grafts 2

Patient Selection for Radial Artery Grafts

• Patients who benefit most from radial artery grafts include those under 75 years of age, women, and patients with preserved renal function 1
• The radial artery should be used to target vessels with subocclusive stenoses (>90% stenosis) to maximize long-term patency 1, 2
• Avoid using the radial artery in patients with chronic kidney disease who have a high likelihood of progression to hemodialysis 1

Technical Considerations for Radial Artery Harvesting

• Before harvesting, objectively assess palmar arch completeness and ulnar compensation, using the arm with the best ulnar compensation 1
• Adhere to a "no-touch" technique during harvesting to optimize patency and durability of the radial artery conduit 3
• Avoid using the radial artery after transradial catheterization 1
• Avoid bilateral percutaneous or surgical radial artery procedures in patients with coronary artery disease to preserve the artery for future use 1

Post-Operative Management

• Use oral calcium channel blockers for the first postoperative year after radial artery grafting to prevent vasospasm 1, 4
• Early studies showed that without proper pharmacologic management, radial artery grafts could develop spasm or the "string sign" 4

Comparison with Other Arterial Conduits

• While the LIMA remains the gold standard conduit for the LAD (Class 1, Level B-NR recommendation), the radial artery has emerged as the preferred second arterial conduit 1
• Bilateral internal mammary artery (BIMA) grafting can be beneficial in appropriate patients (Class 2a, Level B-NR recommendation), but is technically more challenging and has higher risk of sternal wound complications 1
• The right gastroepiploic artery can be used to graft right coronary artery target vessels with subocclusive stenosis if the operator is experienced with this artery 1

Clinical Implications

• Despite strong evidence supporting radial artery use, there remains significant variation in practice, with some centers using it in only 9% of CABG procedures 1
• The extensive use of arterial conduits (>2) instead of saphenous vein grafts for multivessel CABG may provide additional late mortality benefits 1
• Long-term studies show that radial artery harvesting does not lead to hand or forearm symptoms, even at very long-term follow-up 2

The evidence clearly supports the radial artery as the most commonly used and recommended arterial conduit after the LIMA for coronary artery bypass grafting, particularly for the second most important coronary target.