Coronary artery and myocardial inflammatory reaction induced by intracoronary stent

Background Intracoronary stents have been extensively used in percutaneous coronary revascularization. However, despite the breakthroughs and developments associated with this new technology, novel complications and findings have emerged compelling the cardiac surgeon to cope with this new scenario. The presence of an intracoronary foreign body (stent) might induce an inflammatory reaction to the coronary artery and surrounding cardiac muscle. Methods Six patients who previously (2 to 72 weeks) underwent stent insertion and subsequently coronary artery bypass graft surgery had a biopsy taken from the grafted coronary artery distal to the stent and from the adjacent muscle. The samples were processed and stained with hematoxylin and eosin and histologically studied. Results Histologic examination of the coronary artery distal to the stent revealed chronic inflammation and an intimal acute inflammatory infiltrate, with polymorphonuclear leukocytes. The myocardium adjacent to the stent exhibited a significant chronic inflammatory infiltrate and fibrosis, compatible with myocarditis. Conclusions The presence of an intracoronary stent induces a persistent, acute and chronic inflammatory reaction, with involvement of the distal coronary artery and surrounding myocardium. This may have implications when choosing the optimal site distal to the stent for coronary artery bypass grafting.