Comparison of mid-term thrombogenicity of everolimus- versus paclitaxel-eluting stents with the same stent platform.: a coronary angioscopic study

Background: Various reports have been documented for comparison between paxclitaxel-eluting stent (PES) and everolimus-eluting stent (EES) in terms of the degree or charactetristics of neointima coverage or late thrombosis. However, the comparison studies between PES and EES have not been performed on the same stent platform. Method: A total of 38 consecutive patients (male: 29 patients, 67.7±10.0 years old) who underwent PES or EES implantation between November 2011 and Jun 2012 were imaged by coronary angioscopy (PES:Taxus Element™, 22 lesions vs. EES:Promus Element™ 26 lesions) at the baseline and the follow-up period. The follow-up duration was 8.4±1.4 months. Coverage grade of neointima as well as yellow grade of intima (residual plaque or neointima) were semi-quantitatively determined by angioscopy with a grade of 0 to 3. (Coverage grade: none=0, fully covered=3, Yellow grade: whitest=0, yellowest=3). Results: Prevalence of yellow residual plaques (yellow grade ≥ 1) and its yellow grade of residual plaque under the stents were similar between 2 groups at baseline (EES group: 42.9% vs. PES group: 31.6%, p=0.46, 0.8±0.2 vs. 0.4±0.2, p=0.24). The coverage grade of neointima were similar (1.5±0.2 vs. 1.7±0.1, p=0.94) at follow-up. Prevalence of yellow intima (yellow grade ≥1) plaques and the yellow grade of intima were similar between 2 groups at follow-up (59.1% vs. 50%, p=0.53, 0.8±0.2 vs. 0.8±0.2, p=0.84). Incidence of thombus formation was higher in PES group than EES group (4.6% vs. 53.7%, p<0.01). The thrombi were observed frequently over the yellow intima in PES group. Incidence of target lesion revascularization was similar between 2 groups (0% vs. 7.7%, p=0.50). Conclusion: The comparison study on the basis of the same stent platfrom revealed that everolimus and paclitaxel provided similar grade of coverage and yellowness of intima. However, paclitaxel showed higher incidence of thrombus formation than everolimus. This study suggested that paclitaxel might cause higher thrombogenicity than everolimus.