Original title: Randomized comparison of strut coverage between Nobori biolimus-eluting and sirolimus-eluting stents: an optical coherence tomography analysis. Reference:  EuroIntervention 2014; 9-online publish-ahead-of-print February 2014

The aim of this study was to compare strut coverage at six months follow up after Nobori biolimus eluting stent (N- BES) implantation versus Cypher Select sirolimus eluting stent (SES) implantation.

A total of 120 patients with a single stenotic lesion requiring revascularization were randomly assigned to either N-BES (n=60) or SES (n=60). Optical coherence tomography (OCT) was performed post stent implantation, and at six months follow-up. Post-intervention and follow-up OCT analyses were available in 51 (85.0%) and 52 (86.7%) patients, respectively. 

Primary endpoint was the percentage of uncovered struts at 6 months. In addition, an OCT contour plot analysis was constructed to investigate the distribution patterns of uncovered struts. 

The percentage of uncovered struts of N-BES was significantly lower versus SES (15.9±12.2% versus 25.1±18.3%, respectively, p=0.003). N-BES showed a greater NIH thickness than SES (median [interquartile range] 52.4 μm [41.9-74.9] versus 42.1 μm [30.6-56.0], p=0.005).   

Contour plot analyses by OCT showed a lower incidence of a diffuse distribution pattern of uncovered struts in N- BES versus SES (46.8% versus 75.0%, respectively, p=0.022). 

Conclusions:

This randomized OCT study showed that N-BES had a significantly lower percentage of uncovered struts than SES, and less common diffuse distribution pattern of uncovered struts. 

Editorial Comment

This randomized study reinforces the shared idea that biodegradable polymer drug eluting stents are safer. Chronic endothelial inflammation produced by polymers seems significantly less severe. For the first time, a large randomized BES vs SES study with OCT was performed showing that uncovered strut percentage at six months is significantly lower in BES.

Even though major adverse events were not observed in this study, we could infer that patients with BES, with a lower uncovered strut rate and therefore a lower stent thrombosis rate, due to early discontinuation of the dual antiplatelet therapy, would benefit in the long term.

It seems logical to assume the role of biodegradable polymer drug eluting stents as the safest alternative, with no less efficacy. Further analysis is required to assess the safety and efficacy of bioresorbable stents.

Courtesy of Dr. Matías Sztejfman.
Interventional Cardiologist.
Güemes Hospital. Buenos Aires, Argentina.

Dr. Matías Sztejfman