Endothelial Stent Coverage and Neointimal Proliferation at 6 Months After Implantation of a Coronary Everolimus-Eluting Stent Compared With a Bare Metal Stent Postdilated With a Paclitaxel-Eluting Balloon: A Randomised Study Using Optical Coherence Tomography

Background:

Safety concerns regarding use of drug eluting stent systems (DES) are related mostly to late stent thrombosis, which is facilitated by incomplete stent endothelial coverage. Specific information about time course and amount of endothelial strut coverage of different DES is required, in order to further refine the concept of antiplatelet therapy after DES implantation. Optical coherence tomography (OCT) is emerging as a new gold standard for endovascular imaging of stents, atherosclerosis progression, vulnerable plaque and neointimal proliferation. Very limited OCT data about endothelial coverage of DES are currently available. Aim of this study is a comparative evaluation of XIENCE V® everolimus eluting stent (Abbot Vascular) and of the bare metal stent (BMS) Coroflex® Blue postdilated with the drug-eluting balloon (DEB) SeQuent® Please (paclitaxel-eluting balloon, B. Braun Melsungen AG) in terms of endothelial coverage and neointimal proliferation using OCT.

Study Design:

A number of 80 patients scheduled for elective percutaneous coronary intervention (PCI) with a native coronary stenosis suitable for DES implantation and OCT imaging are openly randomized 1:1 to either XIENCE V® or Coroflex® Blue/Sequent® Please. The study is prospectively conducted at a university high-volume PCI center with OCT expertise (Jena, Germany). Angiographic follow-up and OCT imaging with motorized pull-back at 1 mm/s are planned in all patients 6 months after implantation of the study stents. OCT endpoints are: (1) endothelial coverage, expressed as % of struts without coverage and % of stent length containing non-covered struts, and respectively (2) neointimal proliferation, given as % neointimal volumetric proliferation within the whole stent and also as focal peak % neointimal area proliferation. The study is not powered for clinical endpoints, which are: subacute or late stent thrombosis and need for revascularization of the stent segment. Given the high number of measurements (15 cross-section images / 1 mm stent length), OCT endpoints are likely to reach significance at the level P < 0.05 even at a follow-up drop-out rate up to 20%.