Pattern of Endothelialization in Left Atrial Appendage Occluder by Optic Coherence Tomography: A Pilot Study

Device endothelialization and morphology assessments at 1 year using computed tomography angiography: comparison of traditional with novel puncturable atrial septal defect occluders

BACKGROUND

Complete endothelialization is often not achieved within 6 months after implantation of an atrial septal defect (ASD) occluder, which may lead to microthrombus or thrombosis. This study aimed to assess the endothelialization and morphology of a novel puncturable ASD occluder (ReAces) compared with traditional occluders 1 year post-implantation using computed tomography angiography (CTA).

METHODS

Fifteen patients from each group in a randomized controlled trial comparing ReAces with traditional occluders were included at the 1-year follow-up at Zhongshan Hospital, Fudan University. Baseline characteristics and procedural data were recorded. CTA was performed to assess the device morphology and degree of endothelialization. Independent samples t-test and Fisher's exact test were primarily used to compare the above data.

RESULTS

Each patient received a single device and had no residual shunts. There were no differences in defect size (15.3 ± 4.0 mm vs. 15.3 ± 4.7 mm, p = 1.00) or occluder size (21.2 ± 4.4 mm vs. 21.5 ± 5.3 mm, p = 0.882) between the two groups. At the 1-year follow-up CTA, the central region thickness (4.2 mm ± 0.9 mm vs. 7.8 mm ± 2.4 mm, p < 0.0001), left atrial device-occupied volume (1863.3 mm2 ± 404.4 mm2 vs. 4764.4 mm2 ± 2321.2 mm2, p < 0.001), and device compression rates (10.1 ± 4.8% vs. 17.5 ± 5.6%, p = 0.001) were significantly lower in the experimental group. All occluders in the experimental group achieved complete endothelialization, whereas in the control group, 7 patients did not (100% vs. 53.3%, p = 0.006).

CONCLUSIONS

Compared with traditional occluders, ReAces presented a significantly greater complete endothelialization rate, lower central region thickness, lower left atrial device-occupied volume, and lower device compression rates at 1 year post-implantation by CTA.

TRIAL REGISTRATION

Trial registry: ClinicalTrials.gov. Unique identifying number: NCT05371366. Date of registration: 04/05/2022.

Fatigue strength analysis of a new left atrial appendage occluder at different release scales

Owing to its low incidence, small trauma, fast recovery, and high efficiency, left atrial appendage occlusion has become a new strategy for preventing stroke caused by atrial fibrillation. Due to a lack of relevant research information on this emerging technology, the effectiveness, stability, or related complications of occluders are mostly observed from a clinical perspective. However, there are fewer studies on the mechanical properties and safety of these occluders. In this study, a new left atrial appendage occluder is proposed, and a complete numerical simulation analysis framework is established through the finite element method to simulate the actual implantation and service process of the left atrial appendage occluder. Besides, the influence of the structural size and release scale of the occluder on its support performance, occluding effect, and safety is also explored. The results demonstrate that the structural size and release scale exert a significant impact on the support performance, occluding effect, and safety of the occluder. The structural optimization of the occluder contributes to enhancing its mechanical performance, thus ensuring its stability and effectiveness after implantation. Overall, these efforts may lay a scientific foundation for the structural optimization, safety evaluation, and effectiveness prediction of the occluder. Furthermore, these findings also provide effective reference for the application of numerical simulation technology in the research on the left atrial appendage occlusion.