In vitro investigation of an intracranial flow diverter with a fibrin-based, hemostasis mimicking, nanocoating.

Flow diversion aims at treatment of intracranial aneurysms via vessel remodeling mechanisms, avoiding the implantation of foreign materials into the aneurysm sack. However, complex implantation procedure, high metal surface and hemodynamic disturbance still pose a risk for thromboembolic complications in the clinical praxis. A novel fibrin and heparin based nano coating considered as a hemocompatible scaffold for neointimal formation was investigated regarding thrombogenicity and endothelialization. The fibrin-heparin coating was compared to a bare metal as well as fibrin- or heparin-coated flow diverters. The implants were tested separately in regard to inflammation and coagulation markers in two different in vitro hemocompatibility models conducted with human whole blood (n = 5). Endothelialization was investigated through a novel dynamic in vitro cell seeding model containing primary human cells with subsequent viability assay. It was demonstrated that platelet loss and platelet activation triggered by presence of a bare metal stent could be significantly reduced by applying the fibrin-heparin, fibrin and heparin coating. Viability of endothelial cells after proliferation was similar in fibrin-heparin compared to bare metal implants, with a slight, non-significant improvement observed in the fibrin-heparin group. The results suggest that the presented nanocoating has the potential to reduce thromboembolic complications in a clinical setting. Though the new model allowed for endothelial cell proliferation under flow conditions, a higher number of samples is required to assess a possible effect of the coating.