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Dual-therapy sirolimus-eluting stent yields significant late neointimal regression
In the EGO-COMBO study, a dual-therapy endothelial progenitor cell-capturing sirolimus-eluting stent achieved exceptional late neointimal regression, rendering favorable 36-month clinical results with minimal restenosis and no late stent thrombosis.
Researchers for the prospective, single-center study evaluated 61 patients (74 lesions) in need of stent implantation who were treated with 88 dual-therapy sirolimus-eluting stents (Combo, OrbusNeich Medical). The mean age of the participants was 62 years and 47% were men.
The primary endpoint was OCT strut coverage (healing) at various follow-up intervals. All OCT neointimal metrics and morphologies and all clinical events were documented with extended protocols to 36 months. Clinical endpoints included 3-year MACE, defined as cardiac death, MI, stent thrombosis or target vessel revascularization.
Patients underwent four longitudinal, consecutive OCT assessments during 24 months. Baseline OCT was conducted for stent implantation optimization and was replicated at early follow-up (2-5 months) in four randomly assigned monthly groups in a 1:2:2:1 ratio. OCT was repeated in these monthly groups to determine the early healing profile (percentage strut coverage and coverage categories) at 9 months for neointimal metrics and structures, and at 24 months for monitoring neointimal transformation and late catch-up.
The researchers found a progressive increase in strut coverage, as measured by OCT, from 77.1% to 92.5% to 92.7% to 94.9% from 2 to 5 months, with close to 100% coverage by 9 months. There was no late-acquired non-coverage of struts.
At 9-month follow-up, angiographic restenosis requiring revascularization by simple ballooning was seen in only one patient, making the target lesion revascularization rate 1.64%. Angiographic in-stent late loss was 0.24 mm.
At 36 months, the overall MACE rate was 3.3%.
From early healing to 9 months, progressive right shifting suggested neointimal proliferation, but between 9 and 24 months, reverse shifting to the left was discovered, suggesting neointimal regression. Additional assessment confirmed significant late neointimal regression at strut-level neointimal thickness (9-month OCT follow-up, 0.14 mm vs. 24-month OCT follow-up, 0.12 mm), neointimal volume (29.9 mm3 vs. 26.2 mm3) and percent neointimal volume (17.8% vs. 15.7%). The researchers did not observe any Academic Research Consortium definite or probably late stent thrombosis.
“This endothelial progenitor cell-capturing technology with sirolimus elution of the Combo stent seems to deliver good long-term clinical results with significant late neointimal regression,” the researchers wrote. “Further studies are required to evaluate whether this can transform into true long-term clinical benefit.” – by Jennifer Byrne
Disclosure: One researcher reports receiving the study device (Combo stent) as a free investigational device before CE mark, and the core laboratory fee was supported by OrbusNeich Medical. Four other researchers report receiving a fee from OrbusNeich Medical as charge for the independent OCT core laboratory analysis.