Verification of small intestinal submucosa graft stent in vitro

Abstract

Objective To verify the feasibility of using small intestine submucosa for graft stents. Methods A Z-type Nitinol wire stent was used as the metal stent material, and porcine small intestine submucosa was used as the biofilm material to prepare the bio-coated stent. In vitro implantation, extracorporeal pulsation and extracorporeal flexion of the stents were designed based on the requirements for the small intestine submucosa graft stent implantation during the endovascular aneurysm repair and of the mechanical properties of the graft stent during human body activity. The feasibility of using small intestine submucosa for the graft stents was evaluated according to the patency of the stent lumen after the experiment, the presence or absence of cracks in the membrane, and the presence or absence of fracture of the metal stent. Results In the in vitro experiments, all the samples were able to maintain complete tunica and luminal patency except the 8th sample that showed suture rupture. Besides, all the samples showed good rebounding and adhering properties in both in vitro implantations and extracorporeal pulsation pressure experiments, and no dangerous problems were found such as film rupture, suture loss and stent fracture. Conclusion Small intestine submucosa can meet the durability requirements of graft stents, adapt to the conditions of graft stents such as implantation, bending and blood pulsation, and can be used as the covering material of graft stents. Key words: Biological graft; Small intestine submucosa; Graft stent; In vitro test