In an article published on October 9,2010 in Vascular Health and Risk Management, a British journal, the outcome of PCI in small coronary arteries was studied. Small coronary arteries (with a diameter of <3 mm) account for about 40%–50% of all coronary stenoses.
The study correlated outcomes with another study from 1996 that examined in-hospital mortality by mid-LAD diameter in Coronary Bypass Surgery, citing: “Atherosclerosis of small arteries remains a major challenge to revascularization procedures, as coronary artery bypass grafting is limited by high rates of technical failure, and PCI is associated with an increased risk of restenosis and adverse outcome.” 
“Stent implantation results in arterial injury, initiating a vascular-proliferative cascade with smooth muscle cell proliferation and migration resulting in neo-intimal hyperplasia. The amount of hyperplasia is largely independent of vessel size, and thus, late luminal loss, an angiographic measure of post-implantation hyperplasia, is similar across a wide range of vessel diameters. Also, small vessels are more prone to restenosis than larger vessels because they are less able to accommodate neo-intimal tissue without compromising blood flow.”
The authors reviewed balloon angioplasty and the placement of Bare Metal Stents (BMS) and different Drug Eluting Stents (DES) in small vessels with respect to clinical outcomes.
- Small vessel coronary angioplasty is common;
- DES considerably reduces the incidence of restenosis and the need for a repeat procedure as compared with BMS;
- Better outcomes were observed with Everolimus Eluting stent (EES) and Sirolimus Eluting Stent (SES) Stent design and strut thickness along with DES influence the outcomes in small coronary vessels similar to other coronary lesions.