Novel biodegradable device for transcatheter closure of atrial septal defects.

The long-term safety of transcatheter atrial septal defect (ASD) closure devices remains a concern, despite favorable short- and mid-term outcomes. We developed a fully biodegradable atrial septal occluder (ASO) delivered via femoral vein catheterization. The device comprises a double-disc main body of poly(L-lactide-co-ɛ-caprolactone) (P(LA/CL)) and a locking component of polylactic acid with palladium alloy markers. In vitro, pH decreased from 7.56 ± 0.01 to 6.58 ± 0.03 over 16 weeks, mechanical strength was lost by 12 weeks, and mass decreased to 60% at 48 weeks. Device weight declined from 268,002 ± 3,226 (Da) to 2,405.8 ± 159.2 (Da) by 36 weeks. ASDs were closed in twelve pigs in vivo using the Brockenbrough technique. No perioperative or postoperative deaths occurred. Echocardiography and angiography performed up to 18 months confirmed complete closure without residual shunt. Macroscopic examination revealed persistence at 6 months, marked degradation at 12 months, and near-complete resorption with tissue replacement at 18 months. Histological examination revealed cellular infiltration and neotissue formation. These findings indicate that the biodegradable ASO is safe and effective for ASD closure and promotes host tissue regeneration, supporting its translation into clinical trials.