At what degree of coronary artery stenosis is a coronary artery stent typically recommended?

Coronary Artery Stent Indications Based on Stenosis Severity

Coronary artery stenting is indicated for stenosis of 70% or greater in non-left main coronary arteries or 50% or greater in the left main coronary artery when associated with symptoms or demonstrable ischemia. 1

Primary Indications Based on Stenosis Severity

• Significant left main coronary artery stenosis (>50% diameter stenosis) is an indication for revascularization, with CABG being the preferred method, though PCI with stenting is reasonable in selected patients 1
• Stenosis ≥70% in non-left main coronary arteries is considered significant and is an indication for stenting when associated with symptoms or demonstrable ischemia 1
• For intermediate lesions (50-70% diameter stenosis), fractional flow reserve (FFR) assessment is recommended to determine hemodynamic significance; an FFR ≤0.80 indicates a functionally significant stenosis that may benefit from stenting 1, 2
• Life-threatening ventricular arrhythmias in the presence of ≥50% left main stenosis or triple-vessel disease is an indication for urgent revascularization 1

Anatomical Considerations

• Left main equivalent disease (≥70% stenosis of both the proximal LAD and proximal left circumflex artery) is considered significant and warrants revascularization 1
• Three-vessel disease with significant stenoses (>70%) is an indication for revascularization, with CABG often preferred over PCI, especially with complex anatomy (SYNTAX score >22) 1
• Proximal LAD stenosis >70% with 1- or 2-vessel disease is an indication for revascularization, particularly when associated with reduced left ventricular function (EF <0.50) or demonstrable ischemia 1

Functional Assessment for Intermediate Stenoses

• For angiographically intermediate coronary lesions (50-70% diameter stenosis), FFR is reasonable to assess functional significance and guide revascularization decisions 1, 2
• An FFR ≤0.75 identifies coronary stenoses causing inducible myocardial ischemia with high sensitivity (88%), specificity (100%), and overall accuracy (93%) 2
• The FFR range of 0.75-0.80 represents a gray zone requiring clinical judgment; generally, an FFR ≤0.80 is considered functionally significant 2
• Coronary flow reserve (CFR) <2.0 correlates with reversible myocardial perfusion defects with high sensitivity and specificity and may guide revascularization decisions 2

Clinical Scenarios

• In stable angina, stenting is indicated for patients with significant stenosis (>70%) and unacceptable symptoms despite guideline-directed medical therapy 1
• In unstable angina/NSTEMI, significant stenoses (≥70% in non-left main or ≥50% in left main) warrant revascularization 1
• In STEMI patients with suitable anatomy, emergency revascularization is indicated, particularly with significant stenoses in the culprit vessel 1
• Previous CABG patients with significant stenoses (>70%) associated with ischemia and unacceptable angina despite medical therapy should be considered for PCI 1, 2

When to Avoid Stenting

• PCI should not be performed in patients with borderline coronary stenoses (50-60% diameter in non-left main locations) without demonstrable ischemia on noninvasive testing 1
• Stenting is not recommended for insignificant coronary stenoses (<50% diameter reduction) 1
• PCI should not be performed with the primary intent to improve survival in patients with coronary stenoses that are not anatomically or functionally significant (e.g., <70% diameter non-left main stenosis, FFR >0.80) 1, 2
• Stenting should not be performed if the patient is unlikely to tolerate and comply with dual antiplatelet therapy for the appropriate duration 1, 2

Important Considerations and Pitfalls

• The degree of stenosis alone should not be the sole determinant for stenting; clinical presentation, symptoms, and evidence of ischemia should be considered 2
• For intermediate stenoses (50-70%), always consider functional assessment with FFR before proceeding with stenting 1, 2
• In multivessel disease, especially with diabetes, CABG may be superior to PCI and should be considered 1, 2
• The SYNTAX score should be calculated for complex multivessel disease to help determine whether CABG or PCI is more appropriate 1
• Dual antiplatelet therapy compliance is essential after stenting; assess the patient's ability to comply before proceeding with stent placement 1