Approaches to antithrombotic modification of vascular implants

Vascular implants in contact with blood must have high thrombotic resistance. However, in some cases, their implantation is associated with thrombosis and subsequent impaired patency of the blood vessel. Most often, this problem affects implants intended for reconstruction of small diameter vessels, which is associated with hemodynamic features in this part of the bloodstream. These include blood vessel prostheses, tissue-engineered vascular grafts, and endovascular stents. The features of the implant material are of great importance when choosing a method for its modification in order to improve biocompatibility and thromboresistance. The review analyzes current experience in using various methods of immobilizing drugs to the surface of vascular prostheses and endovascular stents made from stable and biodegradable polymers. The prospects of creating thromboresistant vascular grafts and stents by joint immobilization on the surface of the polymer material of drugs with antithrombogenic activity and biologically active molecules that regulate the reaction to a foreign body and implant remodeling were evaluated. Numerous studies in the review demonstrating a wide range of ways to modify blood vessel prostheses, tissue-engineered vascular grafts, and endovascular stents with antithrombotic drugs to increase their thrombosis resistance. The main approaches of antithrombotic modification include conjugation of drugs and biologically active molecules on the implant surface. At the same time, new technologies are aimed not only at inhibiting the process of thrombus formation, but also at reducing the intensity of the inflammation process and stimulating the reparation of vascular tissue.