Comparison of scanning electron microscopy and optical coherence tomography for imaging of coronary bifurcation stents.

Background: Optical coherence tomography (OCT) is a new intracoronary imaging modality that has excellent resolution and image quality and has been used to image neointimal coverage after stent implantation. OCT has been compared to histologic, intravascular ultrasound, and scanning electron microscopy (SEM) studies. However, OCT has not been compared with SEM for imaging stent coverage over side branches.

Objective: The aim of this study was to compare OCT with SEM in imaging neointimal coverage over stent struts bridging coronary side-branch ostia.

Methods: Using a balloon-overstretch in-stent restenosis model, we deployed 38 everolimus-eluting stents across coronary bifurcations in nine pigs. We performed OCT immediately after stenting and 4 weeks later; SEM was performed after euthanizing the pigs. OCT images of each stent were compared to the corresponding SEM image.

Results: We analyzed OCT frames (n=111) for strut-level neointimal coverage and compared them to corresponding SEM images. The concordance correlation coefficient was 0.809 (95%CI; 0.734-0.864) and 0.951 (95%CI; 0.930-0.966) for covered and uncovered struts, respectively.

Conclusions: In a non-atherosclerotic pig model, we showed strong agreement between OCT and SEM in imaging coverage of stent struts bridging side-branch ostia.