Pre-clinical Evolution of a Novel Transcatheter Bioabsorbable ASD/PFO Occluder Device.

ABSTRACT

To date, there has been limited investigation of bioabsorbable atrial septal defect (ASD) or patent foramen ovale (PFO) closure devices using clinically relevant large animal models. The purpose of this study is to explore the function and safety of a bioabsorbable ASD occluder (BAO) system for PFO and/or secundum ASD transcatheter closure. Using a sheep model, the intra-atrial septum was evaluated by intracardiac echo (ICE). If a PFO was not present, atrial communication was created via transseptal puncture. Device implantation across the intra-atrial communication was performed with fluoroscopic and ICE guidance. Our 1st generation device consisted of a main structure of thin Poly(L-lactide-co-epsilon-caprolactone) (PLCL) fibers, and an internal Poly glycolic acid (PGA) fabric. Four procedures validated procedure feasibility. Subsequently, device design was modified for improved transcatheter delivery. The 2nd generation device has a two-layered structure and was implanted in six sheep. Results showed procedural success in 9/10 (90%) animals. With deployment, the 1st generation device did not reform into its original disk shape and did not conform nicely along the atrial septum. The 2nd generation device was implanted in six animals, 3 out of 6 survived out to 1 year. At 1 year post implantation, ICE confirmed no residual shunting. By necropsy, biomaterials had partially degraded, and histology of explanted samples revealed significant device endothelialization and biomaterial replacement with a collagen layer. Our results demonstrate that our modified 2nd generation BAO can be deployed via minimally invasive percutaneous transcatheter techniques. The BAO partially degrades over 1 year and is replaced by host native tissues. Future studies are needed prior to clinical trials.