The initial success of drug-eluting stents in ameliorating restenosis has been tempered by the recognition of an apparently higher incidence of late stent-related complications relative to bare metal stents, including very late stent thrombosis (VLST). Amongst other factors, VLST has been linked to incomplete stent apposition as detected by intravascular ultrasound and/or optical coherence tomography. However, these invasive imaging modalities are not in widespread routine clinical use, and the majority of coronary interventions remain guided by conventional x-ray angiography alone.
While Alfonso and co-workers reported that three patients suffered from VLST associated with angiographic coronary aneurysm, Imai et al described the phenomenon of peri-stent contrast staining (PSS), which they defined as contrast staining outside stent struts insufficient to fulfil the definition of a coronary artery aneurysm (localised dilatation of the lumen; >50% of the diameter of associated reference vessel segment) in a single-centre retrospective cohort study.