Endothelialization of an Amplatzer Septal Occluder Device 6 Months Post Implantation: Is This Enough Time? An In Vivo Angioscopic Assessment

J INVASIVE CARDIOL 2019;31(2):E44.

Key words: Amplatzer septal occluder, angioscopy, antithrombotic therapy, atrial septal defect, neointimal coverage

The current guidelines recommend a minimum of 6 months of antithrombotic and antibiotic prophylaxis following septal occluding device placement for transcatheter closure of atrial septal defect (ASD). Full neoendothelialization is thought to be completed within 6 months of device implantation; however, there is no method available that can assess the level of neoendothelialization in vivo. An autopsy study detected minimal epithelialization on the surface of the metallic mesh 5 months post implantation, while a case of bacterial endocarditis detected 30 months post implantation concluded that the poor tissue endothelialization might have been a cause of the infection.

The Amplatzer atrial septal occluder (ASO; St. Jude Medical) is a commonly used device for percutaneous transcatheter closure of ASDs worldwide; however, to our knowledge, there is currently no in vivo angioscopic investigation that can accurately assess the degree of endothelialization. Therefore, we set out to evaluate the neointimal coverage of ASO using angioscopy (Visible; Fiber Tech Co, Ltd) from a right atrial access (Figure 1A) in a 78-year-old woman with a 22 mm ASO implanted 6 months prior.

Angioscopy revealed that many parts of the device were well covered with white endothelium (Figure 1B; Video 1); however, the metallic wires were exposed, with marked thrombus formation around the center of the device (Figure 1C; Video 2), indicating incomplete endothelialization despite the 6-month postimplantation period.

This first report evaluating endothelialization in vivo demonstrates that 6 months of postimplantation prophylactic therapy may not provide sufficient time for adequate endothelialization. Further investigations are warranted to determine the optimal duration of these treatments after ASD closure.

Acknowledgment. The authors would like to thank Dr Daisuke Fukamachi of the Division of Cardiology, Department of Medicine, Nihon University School of Medicine, for his excellent technical assistance.

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From the Division of Cardiology, Department of Internal Medicine, St. Marianna University School of Medicine, Kanagawa, Japan.

Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. Dr Tanabe, Dr Izumo, and Dr Akashi report grants-in-aid for scientific research from the Japan Society for the Promotion of Science. The remaining authors report no conflicts of interest regarding the content herein.

The authors report that patient consent was provided for publication of the images used herein.

Manuscript accepted September 6, 2018. Address for correspondence: Yasuhiro Tanabe, MD, PhD, Division of Cardiology, Department of Internal Medicine, St. Marianna University School of Medicine, 2-16-1, Sugao, Miyamae-ku, Kawasaki-City, Kanagawa 216-8511, Japan. Email: y-tanabe@muj.biglobe.ne.jp