Development And Mechanical Performance Investigation Of Endovascular Aortic Stent-graft Based On Three-dimensional Printing

Background Aortic dilated diseases included aortic dissection and aortic aneurysm was a kind of serious disease.In recent two decades,the mortality of patients was significantly decreased with the development of endovascular aortic surgical instruments and the improvement of endovascular aortic repair.However,after a long period of follow-up we found the perpetual existence of stent-graft in the vascular may lead to a series of middle-term and long-term complications.The mismatch between the stent-graft and the aortic wall may be the reason why these adverse event happen.Objective The aim of this research was to fabricate a custom-made aortic stent-graft based on three-dimensional printing.We tested radial force of the stent-graft to evaluate the feasibility of in vivo implantation.Methods The different geometries of Z-type stents were generated by computer aided design software.Then the stent manufactured by 3D printer using polylactic acid(PLA)and nylon material.The accuracy of 3D printing was assessed by measuring the wire gauge of the stent.Then we finish the fabrication of stent-graft by electrospinning the poly(l-lactide-co-caprolactone)solution into the stent of the PLA.The mechanical property of stent-graft was evaluated by tensile test.As well as a series of radial force data in the different diameters were assessed by the radial force measurement to select the best geometry of the stent-graft.Results The accuracy of 3D printing was consistent with the digital model.For PLA specimen,the Young's modulus was 1272.8±9.7MPa.The tensile strength was 55.2±1.5 MPa.The tensile strain at break was 6.2±0.6%.The Young's modulus of the nylon specimen was 1099.4±35.0MPa.The tensile strength was 47.9±1.4MPa and the tensile strain at break was 21.0±2.8% for nylon.The Young's modulus of poly(l-lactide-co-caprolactone)membrane was 1.2±0.2MPa.The tensile strength was 6.4±1.7 MPa and the tensile strain at break 347.5±41.0%.We found the greater radial force of PLA stent than the nylon stent.The radial force was maximized when the configuration of PLA stent with the 20 mm in height,8 bend and 1mm wire gauge.The maximum of radial resilience force of the PLA stent was 3.0±0.1N at the diameter of 20 mm.Conclusions The aortic endovascular stent-graft can be made by 3D printing and electrospinning for the treatment of aortic dilated diseases.We can rapidly manufacture custom-made stent-graft via 3D printing with the kind optimized configuration.The use of the stent-graft offers a promising approach reduce the incidence of graft-related complications.