Correlation of Left Atrial Septal Pouch with the Prevalence of Patent Foramen Ovale: A Retrospective Review

Purpose: To determine the prevalence of Left Atrial Septal Pouch (LASP) and assess the association with Patent Foramen Ovale (PFO).

Materials and Methods: We retrospectively reviewed 275 cardiac-gated CT examinations at Indiana University from January 2010 to June 2012, 160 cardiac CTs performed prior to pulmonary vein ablation, 115 for evaluation of coronary artery evaluation. Consensus readings were performed by two readers on a PACS workstation using the Multiplanar Reformat software to identify the presence or absence of LASP and PFO. PFO was diagnosed by the presence of a contrast jet extending from the left atrium to the right atrium.

Results: Overall prevalence of LASP was 24.7% (68 LASPs out of 275 patients). There was no significant difference regarding the gender and age between patients with and without LASP, p-values 0.054 and 0.63 respectively. The overall prevalence of PFO in both groups is low 2.2% (6 PFOs out of 275 patients). The prevalence of PFO in patients with LASP was 5.9% (4 out of 68 patients) and was 1.0% (2 PFOs out of 207 patients) in patients without LASP. There was a significant difference in prevalence of PFO between patients with and without LASP, p-value 0.035.

Conclusions: LASP is a common finding on cardiac CT, its prevalence not affected by age or gender. Patients with LASP have statistically greater prevalence of PFO than patients without LASP, but the prevalence remains low.