Bioresorbable vs Metallic Occluders for Transcatheter Atrial Septal Defect Closure

Importance: The permanent metallic occluders used for atrial septal defect (ASD) closure are associated with risks of late complications and may impede access to the left atrium. Bioresorbable occluders have the potential to address these limitations but have yet to be validated in randomized clinical trials. Objective: To evaluate whether a bioresorbable occluder is noninferior to a metallic occluder based on its efficacy and safety for transcatheter ASD closure. Design, Setting, and Participants: This multicenter, noninferiority, open-label randomized clinical trial included participants with secundum ASD. Enrollment occurred from May 8, 2021, to August 3, 2022, at 10 hospital sites in China. The 2-year follow-up period ended in September 2024. Interventions: Participants were randomized in a 1:1 ratio to receive a bioresorbable occluder (n = 116) or a metallic occluder (n = 114). Main Outcomes and Measures: The primary outcome was the success rate of ASD closure at 6 months (closure success was defined as procedural success with a residual shunt diameter of ≤2 mm, which was assessed using transthoracic echocardiography). At the 2-year follow-up, the occluder groups were compared regarding the success of ASD closure and the device-related adverse events. The degradation profile of the bioresorbable occluder was assessed at 2 years. Results: Of the 230 participants randomized, implantation was not attempted in 1 participant in the bioresorbable occluder group due to a small femoral vein, leaving 229 (median age, 14.1 years [IQR, 7.0 to 37.3 years]; 68% were female). At 6 months, the success rate of ASD closure was 96.5% (111 of 115 patients) for the bioresorbable occluder group vs 97.4% (111 of 114 patients) for the metallic occluder group (between-group difference, -0.8 percentage points [95% CI, -5.0 to 3.7]; P < .001 for noninferiority). At 2 years, there were no statistically significant between-group differences in ASD closure success (94.8% [109/115] in the bioresorbable occluder group vs 96.5% [110/114] in the metallic occluder group; P = .75), or in device-related adverse events (2.6% [3/115] vs 3.5% [4/114], respectively; P = .72). The rate of degradation at 2 years was approximately 99.8% for the bioresorbable occluder. Conclusions and Relevance: A bioresorbable occluder is noninferior to a metallic occluder for ASD closure, with near-complete degradation by 2 years. These findings suggest that a bioresorbable occluder could be a valuable addition to the options for transcatheter ASD closure. Trial Registration: chictr.org.cn Identifier: ChiCTR2100044408.