Abstract 1579: Rapid Normalization Following Percutaneous Secundum Atrial Septal Defect Device Closure. A Study Using The Relative Atrial Index.
Background. The Relative Atrial Index (RAI) (RA area (cm2)/LA area (cm2)) is a novel tool that we have shown to be useful for identifying patients with significant atrial shunting. RAI was used to assess the degree of normalization following percutaneous Amplatzer secundum atrial septal defect (ASD) device closure.
Methods. RAI was derived from the standard apical four chamber view in patients (n=85, mean age 38±21; 55 females) before and after percutaneous ASD closure as well as in the early (mean days 124) and late stages (mean days 390) of follow-up. RAI was also compared to normal valves observed in the general population (excluded significant intrinsic right heart pathology, n=4897).
Results. The RAI in ASD patients was significantly higher than the general population (1.22±0.20 vs 0.81±0.15, p<0.0001). Significant atrial remodeling occurred immediately after transcatheter closure with a reduction in RAI at Day 1 to 0.93±0.16 (p<0.0001) and complete normalization at early follow-up to 0.81±0.12.
Conclusion. Resolution of right atrial enlargement occurs remarkably early after percutaneous ASD closure as demonstrated by the novel tool Relative Atrial Index (RAI). This suggests right atrial enlargement is largely volume-loading dependent rather than structural.