Background: Although drug-eluting stents have significantly reduced the midterm incidence of target lesion revascularization (TLR), in vivo studies on long-term vessel healing of sirolimus-eluting stents (SESs) and paclitaxel-eluting stents (PESs) are limited. The aim of this study was to compare long-term arterial healing with SESs and PESs.
Methods: We evaluated 27 SESs (23 patients) and 21 PESs (20 patients) by serial optical coherence tomography at 6 months (midphase) and >= 3 years (late phase) after stenting and evaluated the change of neointimal thickness (NIT), the percentages of uncovered and malapposed struts, peristrut low-intensity area (region around stent struts with a homogeneously lower intensity appearance than surrounding tissue), thrombus, and atherogenic neointima.
Results: At follow-up, most SESs showed a progressive increase in the average NIT, whereas PESs showed variable changes. Between midphase and late phase, NIT increased significantly in SESs (midphase, 94.1 +/- 49.3; late phase, 130.2 +/- 78.7; P = 0.001) but decreased significantly in PESs (midphase, 167.4 +/- 122.9; late phase, 136.0 +/- 77.7; P = 0.04). The percentages of uncovered struts decreased significantly in SESs; conversely, variable changes were observed in PESs. Peristrut low-intensity area and thrombus formation decreased in SESs but remained largely unchanged in PESs. The prevalence of atherogenic neointima was greater in the late phase than in the midphase in both groups but was similar for both stents.
Conclusions: Long-term vessel healing was different for SESs and PESs. Progressive vessel healing was consistently observed in SESs, whereas a heterogeneous process of delayed vessel healing was noted for PESs.