A novel biodegradable septal defect occluder: the "Chinese Lantern" design, proof of concept

Atrial septal defect (ASD) is a general term used to describe an opening in the atrial septum that divides the two atria; unless the hole is occluded, it can give rise to serious complications. Given the need for percutaneous deployment for ASD or patent foramen ovale (PFO) occluders, all currently available devices are made of metals (specifically nitinol) and synthetic fabric. However, their permanent presence in the human body is not desirable due to the risks of long-term allergy, toxicity, and complications such as thrombus formation, device arm fracture, and nickel allergy. Once the hole is covered by a newly regenerated tissue, the device is no longer needed; thus it is ideal if the device is fully absorbed by the body when healing is completed.

The "Chinese Lantern" device is made of fully biodegradable polymers featured with a unique pull-fold mechanism. The device was inserted across the ASD/PFO model created on Yorkshire swines through a short sheath by hybrid open surgery. X-ray imaging, echocardiography, and postmortem histopathology were obtained during the 1-month follow-up study period.

X-ray imaging showed that the devices were in satisfactory position and stable. Echocardiography showed that there is no shunting from the right atrium to the left atrium, indicating excellent sealing. The in vitro degradation study and postmortem explantation study confirmed that the devices have good integrity during the 1-month trial. Furthermore, the devices appeared to be completely endothelialized after 1 month.

This work proves the feasibility of interventional closure of ASD or PFO with an innovative biodegradable device, which we call the "Chinese Lantern" for its symbolic design.