Negative impact of ultra-thin strut on neointimal coverage condition within one year after implantation as compared to thin sturt in biogradable-polymer sirorimus eluting stents

Abstract

Background: BIOSCIENCE randomized trial which compared biodegradable‐polymer sirolimus‐eluting stents with ultra‐thin (60μm) strut (ultra‐thin BP‐SES) and durable‐polymer everolimus‐eluting stents with thin (81μm) strut (thin DP‐EES) have reported that definite stent thrombosis within 1 year had more frequently occurred in ultra‐thin BP‐SES (0.9%) than in thin DP‐EES group (0.4%) although it was not statistically significant. It suggests that neointimal coverage after stent implantation within 1 year might be different between ultra‐thin BP‐SES and thin DP‐EES. Recently, two types of biogradable‐polymer sirorimus eluting stents, thin (80μm) strut type (thin BP‐SES) and ultra‐thin (60μm) strut type (ultra‐thin BP‐SES), can be available in clinical settings. Purpose: We compared neointimal coverage conditions between ultra‐thin BP‐SES and thin BP‐SES by optical coherence tomography (OCT). Methods: Consecutive Forty‐six patients who underwent 21 ultra‐thin BPSESs or 25 thin BP‐SESs implantation were enrolled. We compared incidences of acute coronary syndrome, type B2/C lesion, atherectomy device use, stent size, stent length, maximum inflation pressure, and 8‐month follow‐up OCT parameters including proportions of uncovered struts (%Uncovered), malapposed struts, (%Mallaposed) and mean neointimal hyperplasia thickness (mean NHT) between the two groups. Results: %Uncovered and %malapposed were significantly higher and mean NHT was significantly lower in ultra‐thin BP‐SES than in thin BPSES (Table). The other parameters were similar between the two groups. Conclusion: Ultra‐thin BP‐SES showed worse neointimal coverage as compared to thin BP‐SES within 1 year after stent implantation, which may increase stent thrombosis.