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Address for correspondence:
Dr. Raman Krishna Kumar, Pediatric Cardiology, Amrita Institute of Medical Sciences, AIMS Ponekkara P.O., Kochi, Kerala 682 041, India
transcatheter closure is an effective alternative to surgery in most patients with atrial septal defects (ASDs) of the secundum type (1,2). Factors that decide suitability for transcatheter closure include size of the defect and presence of adequate tissue rims around the defect (3). Accurate imaging of the anatomic features of the ASD is critical for case selection, planning, and guidance during the procedure. This is accomplished using 2-dimensional (2D) and 3-dimensional (3D) echocardiography and of late, intracardiac echocardiography (ICE). This review focuses on comprehensive imaging through transesophageal echocardiography (TEE) for transcatheter closure of ASDs.
Anatomy of the ASD: Nomenclature of the Rims/Margins
Conventionally, the rims of a secundum ASD are labeled as aortic (superoanterior), atrioventricular (AV) valve (mitral or inferoanterior), superior venacaval (SVC or superoposterior), inferior venacaval (IVC or inferoposterior), and posterior (from the posterior free wall of the atria). By conventional definition, a margin >5 mm is considered to be adequate (3). Podnar et al. (4) defined 10 morphological variations of defects, the most common type being the defect with deficient aortic rim (42.1%). The other variants included central defects (24.2%), deficient inferoposterior rim (12.1%), perforated aneurysm of the septum (7.9%), multiple defects (7.3%), combined deficiency of mitral and aortic rims (4.1%), deficient SVC rim (1%), and deficient coronary sinus rim (1%).
For a comprehensive evaluation of the ASD, TEE is performed in 3 different planes: transverse (0°), longitudinal (90°), and at 45°.
Special TEE Views for Imaging the Inferoposterior Rim
Echocardiography plays a critical role for patient selection, guidance, and post-deployment evaluation for transcatheter closure of ASDs. Understanding the echoanatomic corelation by transesophageal echocardiography is perhaps the most essential requisite to ensure a successful procedure. 3D echocardiography is likely to further this understanding in the future especially in difficult cases like multiple defects and defects with deficient margins.
- American College of Cardiology Foundation