Background: Differences between paclitaxel-eluting stents (PES) and sirolimus-eluting stent (SES) in neointimal proliferation under strictly matched conditions remain to be clarified by optical coherence tomography (OCT).
Methods and results: Between May and December 2007, 27 patients were implanted with a PES and a SES, randomized to either the proximal or distal site in a single coronary artery, and underwent follow-up angiography and OCT examination at 6 months. The frequency of vessel wall apposition with neointima was greater for PES than for SES (92.6% vs 85.8%, P<0.01). The median (25th, 75th percentiles) neointimal thickness (NIT) in PES was significantly greater than that in SES (90 microm [25th: 40 microm; 75th: 200 microm] vs 50 microm [25th: 20 microm; 75th: 140 microm]; P<0.01). Both the average difference between the maximum and minimum NIT in each cross-section and the average difference between the maximum and minimum NIT in the longitudinal axis were larger in PES than in SES (206+/-88 vs 131+/-57 microm; P<0.001, 607+/-243 vs 400+/-185 microm; P<0.001). Low-density spots were significantly more frequently observed in PES than in SES (30.9% vs 17.0%, P=0.001).
Conclusions: Compared with SES, PES had a non-uniform and larger neointimal thickness with fewer uncovered struts, and more peri-strut low-density areas.