Background: Intrastent thrombosis, while rare, has a poor prognosis. Strut non-coverage is one causal factor, especially in cases of resistance to or premature discontinuation of dual antiplatelet therapy.
Aim: To compare neointimal coverage with paclitaxel and zotarolimus drug-eluting stents, using optical coherence tomography (OCT).
Methods: Twenty-two drug-eluting stents (11 paclitaxel-eluting stents and 11 zotarolimus-eluting stents) were examined by OCT, 6 months after implantation. Mean neointimal strut-coverage thickness and percentage neointimal hyperplasia were measured every millimetre. On each OCT image, struts were classified into one of four categories: well-apposed to vessel wall with apparent neointimal coverage; well-apposed to vessel wall without neointimal coverage; malapposed to the vessel wall; or located on a major side branch.
Results: OCT analysis showed a lower percentage of neointimal hyperplasia with paclitaxel-eluting stents than with zotarolimus-eluting stents (17% vs 38% and mean thickness 154 microm vs 333 microm, respectively; p<0.0001). The rate of strut-coverage was greater with zotarolimus-eluting stents than with paclitaxel-eluting stents (99.1% vs 87.1%, respectively; p<0.0001). A non-covered/covered strut ratio greater than 0.3 was observed in 0.5% of zotarolimus-eluting stent OCT images compared with 18% of paclitaxel-eluting stent OCT images (p<0.0001).
Conclusion: Six months after implantation, neointimal hyperplasia was greater with zotarolimus-eluting stents compared with paclitaxel-eluting stents. Conversely, neointimal strut-coverage was better with zotarolimus-eluting stents.