The association between incomplete stent apposition, multiple interstrut hollows, and in-stent thrombus formation in lesions after drug-eluting stent implantation

Abstract

Purpose: Incomplete stent apposition (ISA) assessed with intravascular ultrasound was known as one of risk factors for stent thrombosis. Meanwhile it was reported that peri-stent contrast staining (PSS) was associated with very late stent thrombosis, and was also reported that ISA and multiple interstrut hollows (MIH) were observed in the lesions with PSS using optical coherence tomography (OCT). However, little is known about the association between ISA, MIH, and in-stent thrombus formation in lesions after drug-eluting stent (DES) implantation. Methods: Between May 2008 and January 2013, we performed OCT for 328 in-stent restenosis lesions after DES implantation. Cross-sectional OCT images were analyzed at every 1 mm of the stented site and qualitative assessment of existence of ISA, MIH, and thrombus was performed. ISA was defined as separation of at least 1 stent strut from the vessel wall, and MIH is defined as multiple hollows (the maximum depth >0.5 mm) existing between and outside well-apposed stent struts. The difference in the incidence of in-stent thrombus formation was compared between lesions with and without ISA and MIH. Thrombus was defined as masses protruding into the vessel lumen with a dimension >250 μm. Red thrombus was high-backscattering protrusion with high attenuation. White thrombus was signal-rich low backscattering protrusion with low attenuation. Results: The patients were 271 men and 57 women and the mean age was 68.9±9.4 years. The mean follow-up period from stent implantation was 1.62±1.53 years. The results are shown in the figure. ![Figure][1] Figure 1 Conclusion: ISA assessed with OCT might to be one of risk factors for in-stent thrombus formation in restenosis lesions after DES implantation. MIH might have an effect on only the formation of red thrombus. [1]: pending:yes