Objective The objective of this study was to evaluate whether the plaque morphology can affect the in-stent neointimal hyperplasia.

Methods 74 patients (93 stents) with OCT post-stent implantation were included in the study. Cross-sectional OCT images were analysed at 1-mm intervals (every 15 frames), and 302 cross-sectional images with lipid or calcific lesions under the stent struts were selected. The struts in these sections were divided into four groups according to the plaque conditions under the struts: group 1—struts on the normal vessel, group 2—on the fibrotic lesion, group 3—on the calcific lesion, group 4—on the lipid rich lesion. The neointimal hyperplasia thickness on the stent struts were measured by OCT.

Results The plaque conditions under 806 struts could be detected clearly by OCT. Among them, 157 struts were on the normal vascular wall (the intimal thickness were less than 250 μm by OCT), 344 struts were on the fibrotic lesions, 145 struts on calcific lesions and 160 struts on lipid lesions. The neointimal thickness were 0.132±0.081 μm, 0.148±0.091 μm, 0.150±0.105 μm and 0.166±0.088 μm respectively in group 1–4. The p value was 0.011.

Conclusions The plaque type has impact on the in-stent neointimal hyperplasia. The underlying lipid or calcific components in plaque may promote neointimal hyperplasia after stent implantation.