Initial findings of impact of strut width on stent coverage and apposition of sirolimus-eluting stents assessed by optical coherence tomography.

Objectives: We investigate the influence of stent design on stent coverage at 6-9 months after sirolimus eluting stent (SES) implantation using optical coherence tomography (OCT).

Background: Although some reports suggest that stent design may correlate with stent coverage of stent struts, there were few detailed data whether stent design impact on stent coverage in the same drug-eluting stent.

Methods: A total of 21 SESs (15 patients), who had implanted 2.5, 2.75, and 3.0 mm stents, underwent OCT at 6-9 months after stent implantation. SES is constructed by two different strut width-components; narrow strut width parts (59 μm) and wide strut width parts (115 μm). Thus, we divided stent struts of SESs into two groups: narrow strut width parts (narrow group) and wide ones (wide group). We compared the incidence of incomplete apposed struts, uncovered struts, and neointimal hyperplasia (NIH) thickness between the two groups.

Results: We could detect 2,948 struts (narrow group consisted of 1,132 struts and wide group consisted of 1,816 struts). Incidence of uncovered struts in the narrow group was significantly lower than in the wide group (30.2% vs. 40.8%, P < 0.001), and NIH thickness in the narrow group was significantly greater than in the wide group (127.5 ± 93.4 μm vs. 118.6 ± 81.4 μm, P = 0.03).

Conclusions: Stent design, especially strut width, affects stent coverage of SES. The narrow strut may avoid the absence of stent coverage in SES, which correlates with stent thrombosis.