Optical coherence tomographic comparison of neointimal coverage between sirolimus- and resolute zotarolimus-eluting stents at 9 months after stent implantation

The Resolute zotarolimus-eluting stent (ZES-R) has a thinner stent strut with biocompatible polymer than first generation drug-eluting stents. However, minimal optical coherence tomography (OCT) data exists about vascular responses after ZES-R implantation. This study investigated OCT findings in ZES-R implantation and compared them to those in sirolimus-eluting stent (SES) implantation. A total of 123 lesions (43 ZES-R and 80 SES) in 111 patients were evaluated with OCT at 9 months after stent implantation. Strut apposition, neointimal hyperplasia (NIH) thickness, and stent coverage on each stent strut were evaluated. Mean NIH thickness was significantly greater in ZES-R-treated lesions than in SES-treated lesions (166 ± 73 μm vs. 96 ± 63 μm, respectively, P < 0.001). The percentage of uncovered strut was significantly lower in ZES-R-treated lesions than in SES-treated lesions (4.4 ± 4.8% vs. 10.3 ± 13.2%, respectively, P = 0.05). The percentage of malapposed struts was also significantly lower in ZES-R-treated than in SES-treated lesions (0.1 ± 0.4% vs. 1.5 ± 4.2%, respectively, P = 0.002). Intracoronary thrombus was less frequently detected in ZES-R-treated lesions (4.7% vs. 30.0%, respectively, P = 0.001). ZES-R showed a lower incidence of uncovered or malapposed stent struts and intracoronary thrombus than SES at 9-month follow-up OCT examination. Compared with SES, ZES-R may elicit more favorable vascular responses at the expense of an increased neointimal proliferation.