Fully biodegradable ventricular septal defect occluders: from biomaterials to clinical translation

Ventricular septal defect (VSD) is the most prevalent congenital heart disease (CHD), which is approximately 20% of all congenital cardiac defects. Although transcatheter closure of VSD is a favorable alternative to traditional open-heart surgery, conventional nitinol-based occluders carry permanent risks of atrioventricular conduction disturbances, device erosion, and nickel allergy, which precluded regulatory approval in the United States for perimembranous VSD. Fully biodegradable occluders represent an attractive solution, offering equivalent closure efficacy while eliminating the long-term risks due to a permanent metallic implant. Owing to favorable endothelization-degradation kinetics, biocompatibility, and mechanical performance, polydioxanone (PDO) and poly-L-lactic acid (PLLA) have emerged as the superior framework and membrane materials, respectively. Clinical evidence from case series, retrospective cohort studies, and a multicenter randomized controlled trial suggests high procedural success and favorable short- to mid-term safety, with a low incidence of conduction disturbances following biodegradable VSD occluder implantation. In 2022, the National Medical Products Administration (NMPA) of China has granted regulatory approval for the MemoSorb^® device, which represents the first clinical available fully biodegradable VSD occluder. This review focuses on biomaterials science, structural design principles, preclinical animal studies, and the emerging clinical evidence of fully biodegradable VSD occluder.