Coronary Artery Stenting Thresholds

Anatomic Thresholds for Revascularization

• The American College of Cardiology recommends stenting for coronary stenoses ≥70% diameter in non-left main vessels when patients have unacceptable angina despite guideline-directed medical therapy, or for stenoses ≥50% in the left main coronary artery 1, 2, 3
• The American College of Cardiology recommends CABG as the Class I indication for improving survival in left main disease ≥50% 2, 3
• The American College of Cardiology suggests PCI may be reasonable (Class IIa) as an alternative to CABG in selected stable patients with low-intermediate SYNTAX scores (<33) and clinical characteristics predicting increased surgical risk 2, 3, 4
• The American Heart Association states that ≥70% diameter stenosis in major coronary arteries is the threshold for revascularization to improve symptoms or survival 1, 2, 5, 3

Physiologic Assessment Overrides Pure Anatomy

• The American College of Cardiology states that anatomic stenosis severity alone is insufficient—physiologic significance must be demonstrated 5, 4
• FFR ≤0.80 indicates hemodynamically significant stenosis warranting intervention, according to the American College of Cardiology 8
• FFR >0.80 suggests deferral of PCI is safe, even with angiographically intermediate lesions, as per the American College of Cardiology 8

Clinical Context Modifies Thresholds

• The American College of Cardiology recommends stenosis ≥70% with unacceptable angina despite guideline-directed medical therapy warrants CABG or PCI (Class I) 1, 2, 5, 3
• The American College of Cardiology states that three-vessel disease with ≥70% stenosis (with or without proximal LAD involvement): CABG is preferred over PCI 1, 2, 3
• The American College of Cardiology recommends proximal LAD stenosis ≥70% plus one other major vessel: CABG improves survival 2, 3

Critical Exclusion Criteria (Class III: Harm)

• The American College of Cardiology states that revascularization should NOT be performed if anatomic criteria (<50% left main or <70% non-left main) OR physiologic criteria (normal FFR) are not met (Class III: Harm) 1, 5, 4

Special Populations

• The American College of Cardiology suggests moderate stenoses (50-70%) may warrant intervention during valve surgery (AVR with CABG) 6, 7
• The American College of Cardiology recommends left internal mammary artery grafting is reasonable for LAD stenoses 50-70% during AVR 6, 7

Common Pitfalls to Avoid

• The American College of Cardiology states that visual angiographic assessment overestimates stenosis severity when lesions are ≥50%, leading to unnecessary interventions 9
• The American College of Cardiology warns that diffuse disease without normal reference segments causes underestimation of severity 9
• The American College of Cardiology recommends intermediate lesions (40-70%) require FFR assessment—many angiographically "severe" lesions are not hemodynamically significant 9, 8