Aims: Detailed long-term changes of the neointima in sirolimus-eluting stents (SES) and paclitaxel-eluting stents (PES) are still unclear.
Methods and results: We consecutively enrolled 14 patients (18 SES) and 12 patients (13 PES) who underwent optical coherence tomography (OCT) serially at eight months and 18 months after stent implantation. For 18 SES and 13 PES, OCT was used to visualise 2,486 and 1,361 stent struts at the eight-month and 2,199 and 1,309 stent struts at the 18-month follow-up, respectively. The OCT parameters, including incidence of uncovered and malapposed struts (uncovered and malapposed percentage), average neointimal hyperplasia thickness (NIH thickness) and %NIH volume obstruction, which was defined as ([mean NIH area*stent length]/[mean stent area*stent length])100, and qualitative analysis of the neointima were compared between SES and PES and also compared between the eight- and 18-month follow-up for SES and PES, respectively. The uncovered and malapposed percentage was significantly higher in SES than PES at the eight- and 18-month follow-up, and the NIH thickness and %NIH volume obstruction were lower in SES than PES at both follow-ups. The uncovered and malapposed percentage decreased in both SES and PES between the eight- and 18-month follow-up. Percent NIH volume obstruction and NIH thickness in SES significantly increased from the eight- to 18-month follow-up; however, those parameters significantly decreased in PES. The incidence of high signal with peri-strut low-intensity areas increased in SES but decreased in PES from the eight- to 18-month follow-up.
Conclusions: Uncovered and malapposed struts were reduced in both SES and PES, while the neointimal hyperplasia and qualitative changes showed different patterns.