Peri-stent contrast staining: a stain on the long-term safety of DES?

Drug-eluting stents (DES) have contributed to lowering rates of repeat revascularisation due to a reduction in the occurrence of instent restenosis (ISR)1. However, the risk of stent thrombosis (ST) remains prevalent in the DES era, with several studies associating the use of DES with an increased occurrence of late and very late stent thrombosis (VLST). Delayed healing of the stented arterial segment which involves chronic inflammation with persistent fibrin deposition, and ultimately incomplete stent strut coverage, has been recognised as one of the underlying mechanisms for the late occurrence of ST4. Vessel remodelling, with a larger diameter of the stented segment, predisposes to incomplete stent apposition (ISA), a known risk factor for VLST5,6. Recently, Imai et al described the angiographic phenomenon of peri-stent contrast staining (PSS), defined as contrast staining outside the stent struts insufficient to fulfil the definition of a coronary artery aneurysm, as an angiographic correlate of ISA7 that may help identify patients with higher risk of VLST.