Abstract 2566: Intravascular Ultrasound Guidance may Modify Neointimal Coverage Following Sirolimus-Eluting Stent Implantation
Background: Although sirolimus-eluting stent (SES) has significantly reduced in-stent restenosis, insufficient neointimal coverage may result in adverse outcomes. Intravascular ultrasound (IVUS) guided percutaneous coronary intervention improves the patency of bare-metal stents at follow-up. IVUS guidance at the time of SES implantation may also optimize neointimal coverage following stenting.
Methods: We evaluated 55 SES implanted lesions using both angioscopy and IVUS at follow-up (12±7 months). The lesions were divided into two groups: IVUS guided implantation (group I, n=40); angiography alone (group A, n=15). Neointimal coverage was classified into 4 grades by angioscopy: no coverage (G0); struts bulged into the lumen, but were covered and still translucently visible (G1); struts were visible, but not clear (G2); and struts were embedded and invisible (G3). Minimal stent area (MSA), external elastic membrane (EEM), lumen cross-sectional area (CSA) and plaque burden were measured by IVUS at follow up. Both proximal and distal references were used. Stent expansion was assessed by stent expansion index (SEI) = MSA/reference EEM CSA.
Results: Lesion and procedural characteristics were similar between the groups both at stent implantation and at follow-up. Although the post-procedural quantitative angiographic data were not different between the groups, distribution of the angioscopic grades of neointimal coverage at follow-up were significantly different (group A = 1.0±0.5 grades versus group I = 1.5±0.6 grades, p=0.01). IVUS measurements at follow up showed larger plaque burden at the proximal reference sites (54±12% versus 46±9%, p=0.02) and smaller SEI (0.35±0.09 versus 0.46±0.10, p=0.001) in group A than in group I.
Conclusions: IVUS guidance at the time of SES implantation may modify angioscopic grades of the neointimal coverage, possibly optimizing neointimal coverage and preventing thrombosis.