Background: Serial changes in strut coverage of drug-eluting stents (DESs), which are placed across side-branch vessels, remain unclear.
Methods: The changes in strut coverage of DESs 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 μm on OCT was defined as an uncovered strut.
Results: The percentage of uncovered side-branch struts significantly decreased from 55.7 ± 39.9% to 36.6 ± 32.0% (P<.0001) on serial follow-up: PES, 93.4 ± 10.5% to 67.6 ± 24.2%, P=.018; SES, 47.5 ± 34.4% to 29.6 ± 24.1%, P=.036; and ZES, 26.2 ± 34.8% to 12.4 ± 19.0%, P=.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<.0001). However, compared to other DES types, a significant increase in relatively thin NIH (0 to 30 μm) was observed in PESs (1.6 ± 3.4% to 17.4 ± 16.0%; P=.018).
Conclusion: 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.