Abstract Body: Background: The left atrial septal pouch (LASP) is a blind-ended structure resulting from incomplete fusion of the septum primum and septum secundum during embryonic development, unlike a patent foramen ovale that leaves an interatrial channel open. Recent studies have suggested that LASP could serve as a site for thrombus formation, although its role as an independent risk factor for thromboembolic stroke remains unclear. The aim of this systematic review and meta-analysis was to evaluate and summarize the evidence that the presence of a LASP is a risk factor for cryptogenic stroke.

Methods: We searched PubMed and EMBASE to identify relevant studies. The association between LASP and cryptogenic stroke was estimated by the odds ratio (OR) and 95% confidence interval (CI). Heterogeneity was assessed by χ2-based Q-test.

Results: Eight studies with 2,357 participants from the USA, Europe, and Asia were used in the meta-analysis. We found a significant association between cryptogenic stroke and the presence of LASP (OR 1.60, 95% CI 1.27 to 2.02, p < 0.001). No evidence of heterogeneity was found (Q=6.33, p = 0.50).

Conclusions: This systematic review and meta-analysis adds supports a relationship between LASP and cryptogenic stroke. Further studies are needed to characterize how LASP may impact the risk of recurrent stroke, as well as identification of optimal stroke prevention strategies in the presence of LASP.