Abstract 6026: Heterogeneous Neointimal Coverage Observed in the In-Stent Restenosis Occurred in Sirolimus-Eluting Stents
Background: In-stent restenosis (ISR) in sirolimus-eluting stent (SES) is a rare phenomenon, but intra-stent morphology of the neointima in ISR occurred in SES has not been well defined.
Methods: Angioscopy was performed for 11 ISR lesions of SES in 11 patients (mean age 61±12 years; male 82%; follow up duration 462±152 days). The degree of neointimal coverage and existence of thrombus were evaluated.
Results: Implanted stent diameter was 2.8±0.3 mm; stent length 24±5.0 mm. Minimal lumen diameter was 0.86±0.21 mm; % diameter stenosis 67±8.7%; reference diameter 2.6±0.55mm; lesion length 6.3±2.2mm; and late loss from post-procedure to follow-up was 1.6±0.3mm by quantitative coronary angiography. Six patients (55%) suffered from stable angina pectoris; the others demonstrated silent myocardial ischemia. Ten of 11 SES (91%) showed focal restenosis (lesion length<10mm); one of these showed ISR with stent facture. Another SES had diffuse restenosis (lesion length 12mm). Ten of 11 ISR lesions were located at the mid portion of the stent; another was from stent mid to distal portion. Angioscopically, stent struts were not detected at the site of ISR, covered with “white substance,” whereas sites without ISR showed stent struts that bulged into the lumen, demonstrating incomplete neointimal coverage. In these incomplete coverage sites, 5 stents (45%) showed thrombus (red= 5; white = 0).
Conclusions: SES that suffered from ISR showed angioscopically heterogeneous neointimal coverage: incomplete neointimal coverage in spite of ISR. This may be a potential cause of late stent thrombosis in SES.