Analysis of factors related to successful transcatheter closure of secundum atrial septal defects using the HELEX septal occluder

Abstract

The HELEX septal occluder is a new transcatheter atrial septal defect occlusion device. This study analyzes the data collected from the first US clinical trials with this device to determine the most significant factors in successful use of the device. Tables of subsets of data were constructed in categories of possibly significant patient and device variables compared with important outcomes. Chi2 analysis was used to determine which variables had significant impact on outcomes. The device was successfully implanted in 87% of patients (298/342). A major adverse event occurred in 5.8% (mostly device removal for various reasons). A significant residual leak persisted at 1 year in 2.6%. A fracture of the wire frame occurred in 8%--all were asymptomatic and only 1 required treatment. Overall composite success (no significant leak and no major adverse event) was seen in 91.5%. Patient age, body surface area, and device size had no significant influence on outcomes, except that wire frame fractures were more likely with the 35-mm device. Defect stretch diameter had the largest influence on outcomes, and implantation was possible in only 67% if the stretched diameter of the defect was >20 mm. Device-defect ratio also had a significant effect on delivery success and composite success. The HELEX septal occluder is best suited for small to moderate atrial septal defects with a stretch diameter <20 mm. Although composite success was achieved in 80% of patients when a device-defect ratio <1.6 was necessitated or elected, use of a device that provided a ratio >2 resulted in 95% composite success, and is recommended when possible.