Finite Element Modeling and Analysis of Ventricular Septal Defect Occluders

Transcatheter closure of ventricular septal defect (VSD) has become an alternative therapy to open-chest surgery because of simple procedure, less invasion, and high safety [1–2]. The most important occluder device of the therapy is double-disc structure which occludes the VSD, with the discs of the occluder clamp the margin of VSD while the waist of the occluder supports the VSD hole (Figure 1(a)). Commercially available occluders are woven by 72 nitinol wires (Figure1(b)) and then formed by heat treatment. However, the implantation of metal occluders in perimembranous part will result in a substantial risk of complete atrioventricular block (cAVB) averaging 3.5%, because of its close proximity to the conduction system, which passes at the posterior border of defects [3]. To improve the biocompatibility, Huang [4] developed biodegradable VSD occluders (Figure 1(c)) which woven by polydioxanone (PDO) wires and can be fully absorbed within 24 weeks after implantation.