Intravascular Ultrasound Results From the ENDEAVOR IV Trial : Randomized Comparison Between Zotarolimus- and Paclitaxel-Eluting Stents in Patients With Coronary Artery Disease

ObjectivesThe aim of this study was to compare the vessel response between zotarolimus-eluting stents (ZES) and paclitaxel-eluting stents (PES) using intravascular ultrasound.BackgroundThe ENDEAVOR IV (Randomized Comparison of Zotarolimus- and Paclitaxel-Eluting Stents in Patients With Coronary Artery Disease) trial was a randomized controlled study of zotarolimus-eluting, phosphorylcholine-coated, cobalt-alloy stents for the treatment of de novo coronary lesions compared with using PES for the same treatment.MethodsData were obtained from patients with serial (baseline and 8-months follow-up) intravascular ultrasound analysis available (n = 198). Volumetric analysis was performed for vessel, lumen, plaque, stent, and neointima. Cross-sectional narrowing (given as percentage) was defined as neointimal area divided by stent area. Neointima-free frame ratio was calculated as the number of frames without intravascular ultrasound-detectable neointima divided by the total number of frames within the stent. Subsegment analysis was performed at every matched 1-mm subsegment throughout the stent.ResultsAt follow-up, the ZES group showed significantly greater percentage of neointimal obstruction (16.6 ± 12.0% vs. 9.9 ± 8.9%, p < 0.01) and maximum cross-sectional narrowing (31.8 ± 16.1% vs. 25.2 ± 14.9%, p < 0.01) with smaller minimum lumen area than the PES group did. However, the incidence of maximum cross-sectional narrowing >50% was similar in the 2 groups. Neointima-free frame ratio was significantly lower in the ZES group. In overall analysis, whereas the PES group showed positive remodeling during follow-up (13.7 ± 4.2 mm3/mm to 14.3 ± 4.3 mm3/mm), the ZES group showed no significant difference (12.7 ± 3.6 mm3/mm to 12.9 ± 3.5 mm3/mm). In subsegment analysis, significant focal positive vessel remodeling was observed in 5% of ZES and 25% of PES cases (p < 0.05).ConclusionsThere were different global and focal vessel responses for ZES and PES. Both drug-eluting stents showed a similar incidence of lesions with severe narrowing despite ZES having a moderate increase in neointimal hyperplasia compared with neointimal hyperplasia in PES. There was a relatively lower neointima-free frame ratio in ZES, suggesting a greater extent of neointimal coverage. (The ENDEAVOR IV Clinical Trial: A Trial of a Coronary Stent System in Coronary Artery Lesions; NCT00217269)