Optical coherence tomography findings in lesions after sirolimus-eluting stent implantation with peri-stent contrast staining

We have sometimes noted abnormal angiographic coronary dilatation, <50% of the reference vessel, at the site of sirolimus-eluting stent implantation, suggesting contrast staining outside the stent struts and named this finding peri-stent contrast staining (PSS). Little was known about optical coherence tomography findings of lesions with PSS.

Between May 2008 and March 2010, we performed optical coherence tomography for 90 in-stent restenosis lesions after sirolimus-eluting stent implantation. We found PSS in 20 of the 90 lesions by coronary angiography. The differences in optical coherence tomography findings, including incomplete stent apposition, multiple interstrut hollows (MIH), strut coverage, and thrombus, were compared 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. MIH is defined as multiple hollows (the maximum depth >0.5 mm) existing between and outside well-apposed stent struts. Both incomplete stent apposition (60.0% versus 10%; P<0.001) and MIH (85.0% versus 25.7%; P<0.001) were frequently observed in lesions with PSS than in lesions without PSS. Among the 20 lesions with PSS, there was only 1 lesion in which we found neither MIH nor incomplete stent apposition, but only minor dissection. Uncovered struts (11.6% versus 3.9%; P=0.001), malapposed struts (2.0% versus 0.0%; P<0.001), and red thrombus (35% versus 10%; P=0.012) were frequently observed in lesions with PSS than in lesions without PSS.

PSS might be closely associated with 2 different optical coherence tomography findings, MIH and incomplete stent apposition, in lesions after sirolimus-eluting stent implantation.