What makes a coronary artery a suitable target for coronary artery bypass grafting (CABG)?

What Makes a Coronary Artery a Suitable Target for CABG

A coronary artery is suitable for CABG when it has ≥70% diameter stenosis (or ≥50% for left main disease), supplies viable myocardium, and is technically amenable to grafting with adequate vessel size and distal runoff. 1

Anatomic Criteria for Target Vessel Suitability

Stenosis Severity Requirements

• The target vessel must have ≥70% diameter stenosis in non-left main coronary arteries to justify revascularization. 1
• Left main coronary artery disease requires only ≥50% diameter stenosis to be considered significant. 1
• Stenoses <70% diameter (non-left main) should not be bypassed unless fractional flow reserve is ≤0.80 or there is demonstrable ischemia on noninvasive testing. 1
• Borderline stenoses (50-60% diameter) without demonstrable ischemia are not suitable targets. 1

Vessel Characteristics That Favor CABG Suitability

• Larger reference vessel diameter increases suitability, as this predicts better graft patency and clinical importance. 2
• More proximal vessel location enhances suitability for bypass grafting. 2
• The amount of myocardium supplied (jeopardized myocardium) is a critical determinant—vessels supplying larger territories of viable myocardium are more suitable targets. 1, 2

Technical Considerations

• Total occlusions (99-100% stenosis) are suitable for CABG when there is viable myocardium in the subtended zone and shorter duration of occlusion. 2, 3
• Unlike PCI, CABG suitability is less affected by lesion morphology such as length, calcification, or tortuosity—making CABG favorable for complex lesions. 2
• The vessel must be technically graftable with adequate distal vessel quality for anastomosis. 2

Functional and Physiological Criteria

Viability Assessment

• The target vessel must supply viable myocardium in the region of intended revascularization, particularly in patients with reduced ejection fraction (35-50%). 1, 4
• In patients with severe LV dysfunction (EF <35%), CABG may be considered even without proven viability, though this is a weaker recommendation. 1, 4

Ischemia Documentation

• Target vessels should supply territory with demonstrable ischemia, particularly when considering 2-vessel disease without proximal LAD involvement. 1
• High-risk criteria on stress testing (>20% perfusion defect) or extensive ischemia strengthen the indication for bypass. 1
• Vessels supplying only small areas of viable myocardium should not be bypassed. 1

Clinical Context That Defines Suitable Targets

Multivessel Disease Patterns

• Three-vessel disease with ≥70% stenosis makes all three major vessels suitable targets, with or without proximal LAD involvement. 1
• Proximal LAD stenosis ≥70% plus one other major vessel with ≥70% stenosis defines suitable targets for survival benefit. 1
• Two-vessel disease becomes suitable when there is severe/extensive ischemia or the vessels supply large areas of viable myocardium. 1

Special Populations

• In diabetic patients with multivessel disease, vessels amenable to LIMA-to-LAD grafting are particularly suitable targets, as CABG provides superior survival compared to PCI. 1
• Complex 3-vessel disease (SYNTAX score >22) makes vessels more suitable for CABG than PCI. 1

Vessels That Are NOT Suitable Targets

Critical Exclusions

• Vessels with <70% stenosis (or <50% for left main) without abnormal FFR (>0.80) or demonstrable ischemia should not be bypassed. 1
• Isolated left circumflex or right coronary artery stenosis subtending only small areas of viable myocardium is not a suitable target. 1
• Vessels in patients with insignificant stenosis (<50% diameter) are never suitable targets. 1

Common Pitfalls to Avoid

Do not bypass vessels based solely on angiographic appearance without considering functional significance—13.6% of lesions ≥50% are deemed clinically nonsignificant by experienced angiographers. 2

Avoid grafting vessels that supply non-viable myocardium in patients with prior infarction—viability assessment is essential, particularly when EF is 35-50%. 1, 4

Do not assume all vessels in multivessel disease require grafting—complete revascularization should target only vessels meeting anatomic and functional criteria. 1