Pathobiology of Stent Thrombosis after Drug-Eluting Stent Implantation

First generation drug-eluting stents (DES) have significantly improved the treatment options for patients with symptomatic coronary artery disease by decreasing rates of acute vessel closure and restenosis after percutaneous coronary revascularization procedures. However, early enthusiasm was temperd by reports of late stent thrombosis (LST), which raised concerns about safety. Since millions of DES have been implanted in patients worldwide, it is imperative to understand the pathology of DES in man. Autopsy studies from the CVPath DES registry documented that delayed arterial healing is accompanied by poor endothelialization of stent struts which is the single best predictor of late stent thrombosis. Arterial healing of DES is highly heterogeneous and is dependent on underlying plaque morphology as well as on the stent location. We identified several anatomical and pathological changes in man, which were associated with LST; these include hypersensitivity reaction to polymer, plaque rupture, bifurcation sites, malapposition and stent fracture. DES was also associated with premature atherosclerotic changes versus BMS.