Abstract 4504: Sirolimus-Eluting Stent Promotes Formation of Atherosclerotic Neointima and Yellow Plaque at Stented Lesion: Serial Angioscopic Study
Previous angioscopic studies have revealed that yellow plaques and stent struts were fully covered by white neointima at 1 year after bare metal stent (BMS) implantation. Whereas, at 1 year after sirolimus-eluting stent (SES) implantation, neointima coverage at the stented lesion was incomplete and some yellow plaques were exposed. In such studies, however, whether these yellow plaques were present at implantation or newly formed after implantation has not been clarified. A series of 56 patients (57 lesions) who received implantation of SES were included in this study. Angiographic and angioscopic examinations were serially performed at implantation and at 1 year after implantaiton. Grade of neointima coverage of the stent (not covered, covered by thin layer, or buried under neointima) and maximum yellow color intensity at the stented lesion (Max color grade; 0, white; 1, light yellow; 2, yellow or 3, intense yellow) were angioscopically evaluated. Mean follow-up period was 10.1 ± 3.4 months. Max color grade was significantly higher at 1 year follow-up than at implantation (1.86 ± 0.73 versus 1.37 ± 1.11, p=0.015). Max color grade increased in 25 (44%) lesions, decreased in 23 (40%) lesions and did not change in 9 (16%) lesions at follow-up. Grade of neointima coverage over SES was ‘not covered’ in 17 (29.8%) lesions, ‘covered by thin layer’ in 56 (98.2%) lesions, and ‘buried under neointima’ in 20 (53.1%) lesions, at least in part. In 18 (32%) lesions, yellow plaque was not detected (Max color grade=0) at implantation. Of these 18 lesions, 5 (27.8%) lesions had the area stent was buried under yellow neointima, and 15 (83.3%) lesions had the area yellow plaque was detected under stent at 1 year follow-up. At 1 year after SES implantation, yellow neointima and yellow plaques were newly formed in some lesions. These data indicates that SES implantation promotes the formation of atherosclerotic neointima and yellow plaque at stented lesion.