Study of biodegradable occluder of atrial septal defect in a porcine model.

OBJECTIVE: To evaluate the safety and feasibility of a modified poly(l-lactic acid) (PLLA) atrial septal defect (ASD) occluder. METHODS: Forty-five piglets were divided into two groups: an experimental group (n = 27) and a control group (n = 18). The experimental group underwent percutaneous implantation of a modified PLLA ASD device while the control group underwent percutaneous implantation of a widely used metal ASD device. X-ray imaging, transthoracic echocardiography (TTE), electrocardiogram (ECG), histopathology and electron microscopic examination were performed at 7 days, 1, 3, 6, and 12 months after implantation. RESULTS: Twenty-seven experimental piglets and 18 control piglets were all successfully implanted with modified biodegradable and metal ASD devices, respectively. While both devices exhibited very good occluding effects, the modified PLLA ASD devices were completely endothelialized at 3 months after implantation, and the endothelialization appeared to be more complete compared to the control group. Degradation of the PLLA devices was noted at 12 months follow-up with no loss of integrity at the atrial septum. CONCLUSION: This animal model with implanting of the occluders was effective and not associated with complications. The modified PLLA ASD devices are more controllable and practical than our previous devices. The implanted devices demonstrated good endothelialization and degradability in short and moderate term follow-up. Long-term studies are now underway to further evaluate the biodegradability of this novel device.

A Novel-Design Poly-L-Lactic Acid Biodegradable Device for Closure of Atrial Septal Defect: Long-Term Results in Swine.

OBJECTIVES: The aim of this study is to evaluate the long-term effectiveness and safety of a self-expandable, double-disk biodegradable device made of poly-L-lactic acid (PLLA) for closure of atrial septal defects (ASDs) in swine. METHODS: ASDs were created by transseptal needle puncture followed by balloon dilatation in 20 piglets. The experimental group comprised 18 animals, while the remaining 2 animals were used as controls. Effectiveness and safety were evaluated by rectal temperature, leukocyte count, chest radiography, electrocardiogram, transthoracic echocardiography (TTE), intracardiac echocardiography (ICE), and histologic studies. Animals were followed up at 1, 3, 6, and 12 months. RESULTS: An ASD model was successfully created in 19 animals; 1 piglet died during the procedure. The ASD diameters that were created ranged from 5 to 6.4 mm. Devices were successfully implanted in 17 animals. No animal died during the follow-up studies. Rectal temperatures and electrocardiograms were normal at follow-up, while leukocyte counts transiently increased from 1 to 6 months. Radiography, TTE, ICE, and macroscopic studies demonstrated that PLLA occluders were positioned well, with no shifting, mural thrombus formation, or atrioventricular valve insufficiency. Histologic evaluations showed that PLLA devices were partially degraded in the follow-up study. CONCLUSIONS: ASD closure with the novel PLLA biodegradable device is safe and effective. Longer-term studies are needed to evaluate long-term biodegradability.