P5624Late acquired tissue protrusion after drug-eluting stent implantation: a serial follow-up of 1-month optical coherence tomography imaging

Abstract

Abstract Background Tissue protrusion (TP) between the stent struts after stent implantation has been implicated as a potential factor in the subsequent development of stent thrombosis. However, the incidence, natural history, and predictive factor of TP after stent implantation remains unclear. Purpose To elucidate the fate of TP, we undertook the study assessing TP using short term serial optical coherence tomography (OCT), immediately after deployment of stents and at 1-month follow-up. Methods This was a prospective, single-center study evaluating vascular healing responses with OCT both immediately after and at 1-month after biodegradable-polymer sirolimus-eluting stent (SES) implantation. A total of 18 stable angina patients having OCT-guided PCI with SESs underwent assessment of TP with OCT pre-procedure, post-procedure, and at 1-month follow-up. TP was defined as a tissue prolapse for more than 200 μm between stent struts that directly correlates with the underlying plaque, without abrupt transition and different optical properties. TP was classified into the following 3 groups on the basis of serial assessment: (1) healed, TP present after the procedure but covered by tissue with smooth surface at 1-month follow-up; (2) persistent, TP present both after the procedure and 1-month follow-up; and (3) late-acquired, TP not present at baseline but present at 1-month follow-up. Results Immediately after the procedure, 29 TPs in 13 patients (72%) were identified. Of those, 16 (55%) were healed and 13 (45%) were persistent at 1-month follow-up. Although the size of TP on post-procedural OCT was similar, neointimal area in lesions with healed TP was significantly larger than in lesions with persistent TP due to neointimal proliferation at 1-month follow-up. A synchronous comparison between the post-procedural OCT and the follow-up OCT image showed that 5 TPs were observed only at 1-month follow-up (late-acquired). In lesions with late-acquired TP, calcified nodule or thin-cap fibroatheroma was identified as an underlying plaque morphology on pre-procedural OCT. A representative example is presented in Figure. Incidence of TP and representative case Conclusion Short term serial OCT analysis found that TP can occur not only immediately after SES implantation, but also 1 month after SES implantation. This new concept may provide a new insight into the mechanism of in-stent restenosis and stent thrombosis development after stent implantation. Acknowledgement/Funding None