Purpose: It was reported that peri-stent contrast staining (PSS) was one of abnormal vessel reactions including incomplete stent apposition (ISA) and multiple interstrut hollows (MIH) assessed with optical coherence tomography (OCT), meanwhile positive vessel remodeling could be regarded as one of mechanisms of ISA. The aim of this study was to clarify the relationship between PSS and positive remodeling.
Methods: Between May 2008 and February 2010, we performed IVUS and OCT for 56 in-stent restenosis lesions after sirolimus-eluting stent implantation. We found PSS in 19 of the 56 lesions by coronary angiography. We examined the difference in IVUS parameters including external elastic membrane (EEM) area and remodeling index (RI) at PSS site between lesions with PSS and those without PSS. PSS is defined as contrast staining outside the stent contour extending to >20% of the stent diameter measured by quantitative coronary angiography. ISA was defined as separation of at least 1 stent strut from the vessel wall which is not related to a side branch, and MIH is defined as multiple hollows (the maximum depth >0.5 mm) existing between and outside well-apposed stent struts, assessed with OCT. The remodeling index (RI) was defined as the ratio of EEM area at PSS site to that at the proximal reference site, assessed with IVUS. Positive remodeling was defined as RI >1.05. Furthermore, we examined the difference in EEM area and RI at lesion site between lesions with and without ISA and MIH.
Results: Patients were 45 men and 11 women, and the mean age was 70.1±8.3 years. The results are shown in the figure.
Conclusions: PSS might be closely associated with the existence of positive remodeling, ISA, and MIH.