What are the 3 main heart vessels that are grafted in coronary artery bypass grafting (CABG)?

The Three Main Heart Vessels Grafted in Coronary Artery Bypass Grafting

The three main heart vessels that are typically grafted in coronary artery bypass grafting (CABG) are the left anterior descending (LAD) artery, the left circumflex (LCx) artery, and the right coronary artery (RCA). 1

Left Anterior Descending (LAD) Artery

• The LAD artery is the most important target vessel in CABG, with the left internal mammary artery (LIMA) being the preferred conduit for this vessel 1
• LIMA to LAD bypass is considered a Class I recommendation (highest level of recommendation) in all major cardiac surgery guidelines 1
• The LAD supplies the anterior wall and apex of the left ventricle, making it critical for cardiac function 1
• Proximal LAD stenosis is considered a high-risk lesion that significantly benefits from surgical revascularization 1

Left Circumflex (LCx) Artery

• The left circumflex artery is typically the second most important vessel targeted in CABG 1
• It supplies the lateral wall of the left ventricle and sometimes part of the posterior wall 1
• When the LCx has significant stenosis (>70%), it is commonly bypassed using either:
  • A radial artery graft (preferred over saphenous vein graft) 1
  • A second arterial conduit such as the right internal mammary artery 1
  • A saphenous vein graft if arterial conduits are not available 2

Right Coronary Artery (RCA)

• The RCA is the third major vessel commonly targeted in CABG 1
• It supplies the right ventricle and, in most cases, the inferior wall of the left ventricle 1
• Guidelines recommend arterial grafting of the RCA only when a critical stenosis (>90%) is present 1
• For RCA grafting, saphenous vein grafts are commonly used, though arterial grafts may be considered in specific situations 1

Important Considerations in Vessel Grafting

• The sequence of grafting these vessels can impact outcomes, with some evidence suggesting LAD should be grafted first to minimize myocardial damage 3

• Graft patency rates vary significantly by vessel and conduit type:

  • LIMA to LAD has the highest long-term patency (>90% at 10 years) 1
  • Radial artery grafts show superior patency compared to saphenous vein grafts (89% vs 65-80% at 4-5 years) 1
  • Saphenous vein grafts have declining patency over time (25-50% at 10-15 years) 1

• The decision to graft these vessels depends on:

  • Degree of stenosis (typically >70% for LAD and LCx, >90% for RCA) 1
  • Viability of the myocardium supplied by the vessel 1
  • The patient's overall coronary anatomy and disease pattern 4

Clinical Significance

• Grafting these three main vessels is particularly important in patients with:

  • Left main coronary artery disease 1
  • Three-vessel coronary disease 1
  • Proximal LAD disease with additional vessel involvement 1
  • Diabetes mellitus with multivessel disease 1, 4

• Complete revascularization (addressing all three territories when diseased) generally provides better long-term outcomes than incomplete revascularization 1