Reduction of the risk of thrombosis and restenosis with negatively charged electret covered stents

Rationale: Endovascular implantation may lead to mechanical injury of the vessel walls, their inflammation and subsequent formation of a thrombus in the stented portion of the vessel, as well as to endothelial growth and restenosis. Intimal injury changes the potential of the damaged area from negative to positive.

Aim: To demonstrate the efficacy of corrective negative charge on the stent surface after its endovascular implantation in the reduction of the risk of vessel thrombosis and restenosis.

Materials and methods: With a terminal element technique we created a model for distribution of electrostatic potentials in a healthy and in a partially injured vessel, as well as in a vessel with a negatively charged electret stent. Trials of experimental and serial stents in animals were performed with stent placement into the pig neck arteries with subsequent (at day 21) histological examination of the areas of stent placement. Morphological abnormalities and vessel wall reactions after endovascular carotid stent implantation, such as clot formation and endothelial reaction were assessed.

Results: Negatively charged electret cover of the stent produces corrective electrostatic field to prevent thrombus formation and vascular intima reaction with subsequent restenosis. The use of the stent with negatively charged electret cover ensures a significant reduction of the risk for positive potential inside the injured vessel, thereby dramatically reducing the risk of vessel thrombosis and restenosis. After placement of stents with negatively charged electret cover to animals, there was very mild proliferation of endothelial cells of the vessel wall neointima, compared to that after placement of the reference stents; no thrombus formation was observed. If the reference uncovered stents were placed, there was a dramatic narrowing of the arterial lumen due to proliferation of endothelial neointimal cells, as well as full thrombotic closure of the vessel.

Conclusion: The suggested technology allows for improvement of endovascular stent placement, for reduction of the risk of thrombosis and restenosis after endovascular interventions aimed at revascularization of arterial stenosis.