Preparation and evaluation of a small-diameter vascular graft with dual anticoagulant and anticalcification functions

Cardiovascular diseases have become one of the major threats to human health. There is an urgent clinical need for small-diameter vascular grafts to achieve long-term implantation in the body. In previous studies, some progress has been made, but the prognosis is still poor. Heparin (HEP) is an anticoagulant that is widely applied in the clinical field and commonly used for anticoagulation modification of biomaterials. However, there is an important problem: HEP has almost no direct inhibitory effect on platelet adhesion, which may become one of the potential dangers after graft implantation. In recent years, it has been found that calcification is also a key factor affecting the long-term patency of small-diameter vascular grafts, which is often ignored. Therefore, in this study, based on HEP, procyanidin (PC) was introduced to modify the thermoplastic polyurethane (TPU) grafts fabricated by electrospinning to enhance the anticoagulation and anticalcification properties simultaneously. To verify the effects of drug modification on the material, the physical and chemical characterization, biocompatibility experiments and effectiveness tests of this vascular graft were conducted. The results indicated that the HEP-PC grafts could not only inhibit the excessive proliferation of human umbilical artery smooth muscle cells to some extent but also have excellent hemocompatibility. Particularly, in vivo experiments showed that this graft also achieved dual anticoagulation and delayed the calcification after implantation. These results suggested that HEP-PC-modified TPU might be a promising candidate for inhibiting intimal hyperplasia and anticalcification of small-diameter grafts.