Which coronary vessels can be stented during Percutaneous Coronary Intervention (PCI) and which vessels cannot be stented due to size or other factors, and what percentage of stenosis is considered significant according to the European Society of Cardiology (ESC) and American College of Cardiology (ACC) guidelines?

From the Guidelines

During Percutaneous Coronary Intervention (PCI), most major epicardial coronary arteries and their significant branches can be stented, including the left main coronary artery, left anterior descending artery, left circumflex artery, right coronary artery, and their major branches (diagonal, obtuse marginal, and posterior descending arteries). However, vessels that typically cannot be stented include those smaller than 2.0-2.25 mm in diameter, severely calcified vessels resistant to balloon expansion, extremely tortuous vessels where stent delivery is challenging, and chronic total occlusions that cannot be crossed with guidewires. According to the guidelines, coronary stenosis is generally considered significant when there is ≥70% diameter narrowing in epicardial coronary arteries or ≥50% stenosis in the left main coronary artery, as indicated in the ACC/AHA/SCAI 2005 guideline update for percutaneous coronary intervention 1. The decision to perform PCI should be based not only on anatomical severity but also on clinical presentation, presence of ischemia on non-invasive testing, and patient comorbidities, as recommended in the guidelines 1. Some key considerations for PCI include:

• Focal saphenous vein graft lesions or multiple stenoses in patients who are poor candidates for reoperative surgery 1
• Significant left main CAD (greater than 50% diameter stenosis) in patients who are candidates for revascularization but are not eligible for CABG 1
• Patients with CCS class III angina with single-vessel or multivessel CAD who are undergoing medical therapy and have focal saphenous vein graft lesions or multiple stenoses who are poor candidates for reoperative surgery 1
• Physiological assessment using fractional flow reserve (FFR) is recommended for intermediate stenoses (40-70%), with an FFR ≤0.80 indicating hemodynamic significance. The guidelines emphasize the importance of a comprehensive approach, considering both anatomical and physiological factors, to ensure that interventions are performed on lesions truly responsible for myocardial ischemia rather than on all visible stenoses.

From the Research

Coronary Vessels That Can Be Stented During PCI

• The left main coronary artery can be stented during PCI, as shown in a study published in The New England Journal of Medicine 2.
• The left anterior descending artery (LAD), right coronary artery (RCA), and left circumflex coronary artery (LCX) can also be stented during PCI, as mentioned in a study published in the International Journal of Cardiology 3.
• The proximal LAD, RCA, and LCX can be stented, but the frequency of restenosis and stent thrombosis may vary depending on the vessel and stent type, as reported in a study published in the Journal of Clinical Medicine 4.

Coronary Vessels That Cannot Be Stented Due to Size or Other Factors

• Small vessels, especially those with a diameter less than 2.5 mm, may not be suitable for stenting due to a higher risk of restenosis and stent thrombosis, as mentioned in a study published in the Journal of Clinical Medicine 4.
• Vessels with significant calcification, tortuosity, or bifurcation lesions may also be challenging to stent and may require special techniques or devices, as reported in a study published in the European Heart Journal 5.

Percentage of Stenosis Considered Significant

• The European Society of Cardiology (ESC) and American College of Cardiology (ACC) guidelines consider a stenosis of 50% or more in the left main coronary artery or 70% or more in other major epicardial coronary arteries to be significant, as mentioned in a study published in JACC: Cardiovascular Interventions 6.
• However, the significance of stenosis may also depend on other factors, such as the presence of symptoms, ischemia on stress testing, and the overall clinical context, as reported in a study published in The New England Journal of Medicine 2.

Stent Types and Vessel Sizes

• Drug-eluting stents (DES) are preferred over bare metal stents (BMS) for most coronary interventions, especially in smaller vessels, due to their lower risk of restenosis, as mentioned in a study published in the European Heart Journal 5.
• The choice of stent type and size depends on various factors, including the vessel diameter, lesion length, and patient characteristics, as reported in a study published in the Journal of Clinical Medicine 4.