Serial optical coherence tomography-based observation of strut coverage on drug-eluting stent crossing side-branch vessels

Abstract

Serial changes in strut coverage of drug-eluting stent (DES), which are placed across side-branch vessels, remain unclear. The changes in strut coverage of DES crossing side-branch vessels (size ≥2.0 mm) were serially evaluated by optical coherence tomography (OCT) in 30 patients at 9 months and 2 years after the index DES implantation. DESs were paclitaxel-eluting stents (PESs), sirolimus-eluting stents (SESs), and zotarolimus-eluting stents (ZESs) each in 10 patients. Measured neointimal hyperplasia (NIH) thickness of 0 m on OCT was defined as an uncovered strut. The percentage of uncovered side-branch struts significantly decreased from 55.7 ± 39.9% to 36.6 ± 32.0% (p < 0.0001) on serial follow-up: PESs, 93.4 ± 10.5% to 67.6 ± 24.2%, p = 0.018; SESs, 47.5 ± 34.4% to 29.6 ± 24.1%, p = 0.036; and ZESs, 26.2 ± 34.8% to 12.4 ± 19.0%, p = 0.028. Among covered side-branch struts, the overall percentage of struts with NIH thickness more than 30 µm significantly increased from 36.3 ± 37.4% to 51.0 ± 36.0% (p < 0.0001). However, compared to other DESs, a significant increase in relatively thin NIH (0 to 30 µm) was observed in PES (1.6 ± 3.4% to 17.4 ± 16.0%, p = 0.018). Serial follow-up OCT examination showed a significant decrease in the percentage of uncovered side-branch struts, and the coverage pattern differed with DES type.