In Vitro Quantification of Luminal Denudation After Crimping and Balloon Dilatation of Endothelialized Covered Stents
Covered stents have been demonstrated to reduce restenosis; however, the membrane’s limited biocompatibility can still lead to thrombus formation. To obtain optimal surface hemocompatibility, endothelialization of the luminal surface has been proposed. However, the effect of delivery procedures, such as crimping and balloon dilatation, on the endothelial layer has not been quantified. This study investigated the impact of such procedures on endothelialized covered stents in vitro.
Using an injection molding technique, bare metal stents were covered with fibrin subsequently, endothelialized and conditioned in a bioreactor under arterial pressure (80–120 mmHg) and shear stress (1 Pa). For each set of experiments, three covered stents were prepared, one being subjected to crimping alone, one to crimping followed by balloon dilatation and one serving as control. The experiment was repeated three times. The endothelial coverage was quantified by scanning electron microscopy (SEM). The functionality of the endothelium after exposure to platelet-rich plasma was evaluated by immunohistochemistry and SEM.
The mean endothelial coverage of control, crimped, crimped and balloon-dilated stents was 87.6, 80.1 and 52.1%, respectively, indicating that endothelial cells detached significantly not after crimping (P = 0.465) but following balloon dilatation (P < 0.001). The cells present on the stent’s surface, either after crimping or crimping followed by balloon dilatation, expressed eNOS and CD31 and exhibited no platelet adhesion.
The simulated delivery procedure resulted in the retention of viable cells on more than half of the luminal surface. The main damage to the layer occurred during balloon dilatation.
KeywordsEndothelial layer Endovascular treatment Peripheral arterial disease Tissue engineering
This research project was supported by the START-Program of the Faculty of Medicine, RWTH Aachen.
Compliance with Ethical Standards
Conflict of interest
On behalf of all authors, Shigeo Ichihashi, Frederic Wolf, Thomas Schmitz-Rode, Kimihiko Kichikawa, Stefan Jockenhoevel and Petra Mela, the corresponding author states that there is no conflict of interest.
This article does not contain any studies with human participants or animals performed by any of the authors.
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