Protein Fouling in Vascular Implants

1. Protein Fouling in Vascular Implants Madeline Lok, Matthew Rakochey, Gillian McKercher, Michael Mislan Schulich School of Engineering, University of Calgary Group 18 Vascular Implants Clot Formation • Vascular implants are a patented medical devices used in the treatment of an abnormality in the vein or an artery. Two particular implants discussed are vascular stents and vascular grafts. • Complications include fouling or protein build up on these devices causing blood clot formation. This includes: • restenosis • thrombogenicity at the graft surface • Blood-material interactions can lead to the formation of blood clots by two mechanisms • Contact activation occurs when factor FXII comes into contact with a negatively charged surface and changes shape • Platelet activation occurs when Fibrinogen adsorbs to a hydrophobic surface and platelets adhere to the vessel wall Protein Adsorption Implant Biomaterials The success and durability of a vascular implant is extremely dependent on the chosen material. There are six major factors influencing the selectivity of a material: • Interaction with Water • Drug Elution • Surface Charges and Chemical Structure • Stability • Physical Structure • Result in Clinical Trials While the listed thromboresistent characteristics are important, a material’s success in clinical trials is the ultimate determining factor for its production in practical therapy. (will post images) e-PTFE (like Gore-Tex) versus PEO