Introduction

Restenosis after sirolimus-eluting stent (SES) implantation occurs in a small though sizeable proportion of cases. In the RAVEL trial,18 no cases of restenosis were seen. In the SIRIUSs trials, however, which involved lesions of higher complexity, restenosis did occur in a number of cases.19-21 In these latter studies, post-SES restenosis has been observed to occur either at the edges of the stent or within the stent itself. In the SIRUS trial,19 from a total post-SES restenosis rate of 8.9%, most of the restenoses occurred at the edges of the stent (5.7% at the edges and 3.2% in-stent), with the proximal border being more frequently restenotic than the distal one. Also, in the C-SIRIUS trial,21 no cases of post-SES restenosis were observed within the stented area, whilst 2.3% of the cases had restenosis at the stent edge. Conversely, in the recent E-SIRIUS trial,20 a predominance of edge post-SES restenosis was not observed. Instead, the total restenosis rate after SES implantation was 5.9%, of which 3.9% occurred inside the stent area. Moreover, in a preliminary report from a consecutive series of cases, Colombo et al have shown that most postSES occurred as focal or multifocal lesions inside the stent.198 Recently, Fujii et al observed that stent underexpansion may be a significant cause of recurrent restenosis after SES implantation treatment of in-stent restenosis.199