Appearance of neointima according to stent type and restenotic phase: analysis by optical coherence tomography

Aims: The features of neointima after bare metal stent (BMS) or drug-eluting stent (DES) implantation have not yet been fully characterised. The aim of this study was to investigate in-stent neointima characteristics according to stent type and restenotic phase. Methods and results: The study included 59 consecutive patients undergoing target lesion revascularisation for in-stent restenosis (ISR) evaluated by optical coherence tomography (OCT) during the early phase (<= 1 year, n=30) and late phase (>1 year, n=29) after either BMS (n=37) or DES (n=22) implantation. The OCT signal patterns of tissues at the minimal lumen area were categorised into three patterns: (1) homogeneous high-signal band, (2) heterogeneous mixed-signal band, and (3) lipid-laden intima. The predominant OCT pattern was homogeneous high-signal band in the BMS early phase (19/21 [91%]), lipid-laden intima in the BMS late phase (12/16 [76%]), and heterogeneous mixed-signal band in the DES late phase (9/13 [69%]). Heterogeneous mixed-signal band was seen more frequently in the DES early phase compared with BMS early phase (44% vs. 9%, p<0.05). Conclusions: There were differences of neointima according to stent type and restenotic phase, and this may lead to a better understanding of the different mechanisms of ISR.