Drug diffusion and biological responses of arteries using a drug-eluting stent with nonuniform coating

One-year performance of thin-strut cobalt chromium sirolimus-eluting stent versus thicker strut stainless steel biolimus-eluting coronary stent: a propensity-matched analysis of two international all-comers registries

OBJECTIVES

Recent improvements in coronary stent design have focussed on thinner struts, different alloys and architecture, more biocompatible polymers, and shorter drug absorption times. This study evaluates safety and efficacy of a newer generation thin-strut cobalt chromium sirolimus-eluting coronary stent (SES, Ultimaster) in comparison with a second-generation thicker strut stainless steel biolimus-eluting stent (BES, Nobori) in percutaneous coronary intervention (PCI) practice.

METHODS

A propensity score analysis was performed to adjust for differences in baseline characteristics of 8137 SES patients and 2738 BES patients of two PCI registries (e-Ultimaster and NOBORI 2). An independent clinical event committee adjudicated all endpoint-related adverse events.

RESULTS

The use of SES, as compared with BES was associated with a significantly lower rate of myocardial infarction (MI) (1.2% vs 2.2%; P = 0.0006) and target vessel-related MI (1.1% vs 1.8%; P = 0.002) at 1 year. One-year composite endpoints of all predefined endpoints were lower in patients undergoing SES implantation (target lesion failure: 3.2% vs 4.1%; P = 0.03, target vessel failure: 3.7% vs 5.0%; P = 0.003, patient-oriented composite endpoint 5.7% vs 6.8%; P = 0.03). No significant differences between SES and BES were observed in all-cause death (2.0% vs 1.6%; P = 0.19), cardiac death (1.2% vs 1.2%; P = 0.76) or stent thrombosis (0.6% vs 0.8%; P = 0.43).

CONCLUSIONS

These findings suggest an improved clinical safety and efficacy of a newer generation thin-strut SES as compared with a second-generation thicker strut BES.

Comparisons of early vascular reactions in biodegradable and durable polymer-based drug-eluting stents in the porcine coronary artery

Current drug-eluting stents have abluminal polymer coating; however, thrombus formation in these compared with that in uniformly coated stents remains controversial. We evaluated thrombus formation and early endothelialization after using abluminal biodegradable polymer-coated sirolimus- (BP-SES), and everolimus-eluting stents (BP-EES) versus a durable polymer-coated everolimus-eluting stent (DP-EES) in an in vivo setting. BP-SES, BP-EES, and DP-EES (n = 6 each) were implanted in coronary arteries of 12 mini-pigs that were then sacrificed after 7 and 10 days. Stents were stained with hematoxylin and eosin, and a combined Verhoeff and Masson trichrome stain. Areas of fibrin deposition were digitally detected and measured with off-line morphometric software. Stents were investigated for re-endothelialization by transmission electron microscopy. At 7 days, histological analysis revealed the lowest area of fibrin deposition in BP-SES (BP-SES vs. BP-EES vs. DP-EES; 0.10 ± 0.06 mm2 vs. 0.15 ± 0.07 mm2 vs. 0.19 ± 0.06 mm2, p = 0.0004). At 10 days, the area of fibrin deposition was significantly greater in DP-EES (0.13 ± 0.04 mm2 vs. 0.14 ± 0.05 mm2 vs. 0.19 ± 0.08 mm2, p = 0.007). Endothelial cells in BP-SES demonstrated a significantly greater number of tight junctions than those in DP-EES according to by transmission electron microscopy for both days (p<0.05). Various parameters, including an inflammatory reaction and neointimal formation, were comparable among the groups at 7 and 10 days. An abluminal biodegradable polymer-coated SES showed the least fibrin deposition and greatest endothelial cell recovery at an early stage following implantation in the coronary arteries of mini-pigs.