Left Atrial Septal Pouch—Is it Really a New Risk Factor for Ischemic Stroke?

Abstract

Purpose: The atrial septal pouch is an anatomic variant of the interatrial septum caused by incomplete fusion of the septum primum and secundum. It is debatable whether coexistence of septal pouch and atrial fibrillation (AF) increases the risk of stroke. Thus, the aim of the study was to evaluate the coexistence of left atrial septal pouch (LASP) and AF in patients with a history of stroke in comparison with those without an earlier history of stroke. Materials and Methods: We analyzed 145 patients with AF (68 in the study group, 77 in the control group). The study group consisted of patients with previous stroke and AF; control group consisted of patients scheduled for AF ablation. All patients underwent computed tomography with the assessment of atrial septum morphology and presence of LASP. The study was a subanalysis of the ASSAM (AssesSment of the left atrial appendage morphoLogy in patients aAfter ischaeMic Stroke) study. Results: The prevalence of LASP in the entire group was 38.6%. There were no significant differences in the prevalence of LASP between the study and control groups (33.8% vs. 42.9%, P=0.265). Mean longitudinal and transverse dimensions of LASP were 9.34±3.27 and 2.4±0.6 mm, respectively, and there was no significant difference between the study and controls. Patients from the stroke group were older (P<0.0001), had a higher CHA2DS2-VASc score (5.41±1.93 vs. 1.62±1.46, P<0.0001) compared with controls. Conclusions: Presence of LASP is not more prevalent in patients with a history of stroke. Additional information on the presence of LASP do not improve accuracy of risk stratification for stroke in patients with AF.

The 2022 FASEB Virtual Catalyst Conference on the Cardiac Interatrial Septum and Stroke Risk, December 7, 2022

“…Thus, this study did not support an association between the presence of a LASP and ischemic stroke 73 . In the following years, three studies supported the role of LASP as a stroke risk factor, two with very low LASP frequencies and one with very high LASP frequency instead, which suggests different diagnostic criteria; two other studies, however, were against it 57,68,69,74,75 . Then, the results of two meta‐analyses were also discordant, leaving uncertainty about the real role of LASP as a stroke risk factor 70,76 …”

“…73 In the following years, three studies supported the role of LASP as a stroke risk factor, two with very low LASP frequencies and one with very high LASP frequency instead, which suggests different diagnostic criteria; two other studies, however, were against it. 57,68,69,74,75 Then, the results of two meta-analyses were also discordant, leaving uncertainty about the real role of LASP as a stroke risk factor. 70,76 Contrasting the APRIS study and Dr. Kapoor's study, notable differences include patients' age (the average age 70 vs. 58, respectively) and the frequency of LASP in the cryptogenic stroke subgroup (32% vs. 43%, respectively).…”

Cross-sectional imaging findings of cardiac outpouchings

“…ASPs can cause thrombus formation, and arrhythmogenic focus can be detected in ASPs ( Figure 12 ). 14 Left-sided ASPs have been associated with thromboembolism, stroke, PFO, and atrial fibrillation. Treatment is not recommended in patients with ASPs unless complications develop.…”