Bioresorbable occluders and non-fluoroscopic procedures: A new era in percutaneous treatment of congenital heart disease
On October 23, 2025, the Journal of the American Medical Association (JAMA) published online a multicenter, randomized study led by Chinese scientists, demonstrating that a novel fully bioresorbable occluder for atrial septal defect (ASD) closure exhibits non-inferior efficacy and safety compared to conventional metal occluders, with near-complete degradation achieved within 2 years.1 This landmark achievement, based on China's independently developed bioresorbable occluder, opens a promising pathway for the future evolution of occluder technology.
ASD is a common congenital heart defect, accounting for approximately 10% of all congenital heart diseases. Patients with significant shunting or clinical symptoms require intervention. For decades, transcatheter metallic occluder implantation has been the primary treatment, valued for its minimal invasiveness and rapid recovery.2 However, most metallic occluders are composed of nickel-titanium alloy, which carries risks of inflammation and erosion and is contraindicated in patients with metal allergies (Figure 1A). Long-term implantation may also lead to complications, such as arrhythmia and thrombus formation, while potentially obstructing future transseptal access.
In light of these limitations, bioresorbable occluders represent a promising alternative.3 To optimize performance, the device is fabricated from a composite of polydioxanone (PDO) and poly-L-lactic acid (PLLA). PDO provides structural support with its favorable rigidity and elasticity and degrades relatively rapidly, forming the framework of the occluder’s discs. PLLA, which degrades more slowly, constitutes the flow-blocking membrane (Figure 1B). During the early post-implantation phase (≤3 months), the gradual degradation of PDO is complemented by PLLA’s sustained presence, promoting endothelialization and preventing ASD recurrence. Moreover, PDO offers excellent echogenicity, enabling the entire procedure to be guided solely by echocardiography without fluoroscopy.
This randomized, open-label, non-inferiority trial was conducted across 10 hospitals in China. A total of 229 patients were randomized to receive either the bioresorbable (n = 115) or metallic (n = 114) occluder. The primary endpoints—closure success rate at 6 months—were 96.5% in the bioresorbable group and 97.4% in the metallic group, with a between-group difference of −0.8% (95% confidence interval [CI]: −5.0%–3.7%), confirming non-inferiority (p < 0.001). No major adverse events (e.g., device embolization, displacement, or death) occurred in either group throughout the 24-month follow-up. Full analysis set (FAS) results showed no significant difference in closure success at 24 months (94.8% vs. 96.5%; p = 0.748). Although perioperative device-related event rates were similar between groups (2.6% vs. 3.5%; p = 0.722), the bioresorbable group exhibited superior outcomes at 24 months, including significantly fewer electrocardiographic abnormalities and stable mitral regurgitation, in contrast to the progression observed in the metallic group. No patient required surgery for valvular regurgitation, and improvements in tricuspid regurgitation were comparable between groups.
Quantitative echocardiographic analysis further revealed a progressive reduction in the double-disc area of the bioresorbable occluder over time. The device exhibited favorable degradation kinetics: an initial slow phase (∼5% in the first month) ensured structural integrity during healing, followed by accelerated degradation (∼80% within 1 year). By 24 months, the median hyperechoic areas of both discs diminished to 0 mm2, corresponding to a degradation rate of ∼99.8%, indicating near-complete absorption.
