Clinical Significance of Septal Malalignment for Transcatheter Closure of Atrial Septal Defect

Background. Septal malalignment is related to erosion and device embolization in transcatheter closure of atrial septal defect (ASD), but limited information is available. Objectives. This study aimed to assess clinical significance of septal malalignment and to determine appropriate evaluation of ASD diameter, including the selection of device size. Methods. Four hundred and seventeen patients with ASD who underwent transcatheter closure were enrolled. Septal malalignment was defined as separation between the septum primum and the septum secundum on transesophageal echocardiography. Results. One hundred and eighty-four patients had septal malalignment. The frequency of septal malalignment increased with age reaching around 50% in adult patients. Septal malalignment was related to aortic rim deficiency. The distance of separation between the septum primum and the septum secundum was 5 ± 2 mm (range, 1-11 mm). In patients with septal malalignment, the ASD diameter measured at the septum primum was 19 ± 6 mm, while the ASD diameter measured at the septum secundum was 16 ± 6 mm. There was a difference of 4 ± 2 mm (range, 0-8 mm) between the ASD diameter measured at the septum primum and that measured at the septum secundum. For transcatheter closure, the Amplatzer Septal Occluder device size 2-3 mm larger and the Occlutech Figulla Flex II device size 4-7 mm larger than the ASD diameter measured at the septum primum were frequently used. During the study period, erosion or device embolization did not occur in all of the patients. Conclusions. Septal malalignment is highly prevalent in adult patients with aortic rim deficiency. The measurement of ASD diameter at the septum primum can be valuable for the selection of device size in patients with septal malalignment.