Assessment of spatial distribution of healing, 6 months after zotarolimus-eluting stent implantation.
Forty-two zotarolimus-eluting stents were monitored by optical coherence tomography 6 months after implantation. Mean neointimal strut coverage thickness and percentage of neointimal hyperplasia were measured every millimetre. Non-covered strut ratios were assessed on each slice. In addition, the spatial distribution of neointimal hyperplasia and strut coverage were analysed longitudinally on five stent segments and axially on each slice.
There were no clinical events at 6 months under dual antiplatelet therapy. The optical coherence tomography analysis showed a mean neointimal hyperplasia thickness of 333 ± 147 μm and neointimal hyperplasia obstruction of 36.1 ± 12.3 % . The percentage of covered struts at 6 months was very high (98.9 % ). Only 6/745 slices analysed (0.8 % ) had non-covered strut ratios exceeding 30 % . There was no significant heterogeneity in either longitudinal or axial neointimal hyperplasia distribution. No thrombi were observed.
This optical coherence tomography study found relatively constant neointimal hyperplasia thickness, regardless of the zotarolimus-eluting stent length or diameter. This spatially homogeneous neointimal hyperplasia was associated with near-total coverage of all struts, 6 months after implantation.