No Room for Excess Room: Cobra Head Deformity of Both Discs of an Amplatzer Atrial Septal Occluder Device

Keywords: atrial septal defect, device complications

A 25-year-old female patient with a 30-mm ostium secundum atrial septal defect received a transesophageal echocardiogram-guided device closure. The 32-mm Amplatzer atrial septal occluder (ASO) device was carefully prepared and loaded through a 12-Fr delivery sheath. While deploying the device, a persistent cobra head deformity of the left atrial (LA) disc with proper right atrial (RA) disc shape (Figure 1A) was noted, hence the device was retracted into the sheath. The device’s complete exteriorization and introspection revealed a persistent cobra head deformity involving both atrial discs (Figure 1B). Analyzing retrospectively, inadvertent infolding of the RA disc edge while retracting into the sheath led to deformity of the RA disc as well (Figures 1C, 1D; Video 1). The procedure was completed successfully using a different device through a 12-Fr sheath (34-mm Amplatzer ASO) (Figure 1E).

Cobra head deformity is one of the various shape memory abnormalities encountered in nitinol septal occluders. Most deformations are subtle and transient, while a few remain persistent, requiring a change of device. Common reasons include: restraint of the left disc by the left atrial structures; larger devices; use of disproportionately large delivery sheaths that causes infolding of the disc edge; an excessive force or twist of the device either while advancing or retracting into the sheath; angulation or kink in the delivery system; manufacturing defects; and lower ambient temperature of the saline in the catheterization laboratory. To our knowledge, this is the first case in the literature citing cobra head deformity of both atrial discs. A large delivery sheath with excess room possibly led to deformity in our case. This case highlights the importance of following manufacturer-recommended sheath sizes for optimal device implantation.

Affiliations and Disclosures

From the Department of Cardiology, SRM Medical College and Research Centre, Potheri, Chengalpattu, Tamilnadu, India.

Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. The 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 January 15, 2022.

Address for correspondence: Sriram Veeraraghavan, MD, DM, Associate Professor, Department of Cardiology, SRM Medical College Hospital and Research Centre, SRM Nagar, Potheri, Chengalpattu, TN, India 603203. Email: srivats.007.2003@gmail.com