Role of interatrial block in modulating cryptogenic stroke risk in patients with patent foramen ovale: a retrospective study

Abstract

Abstract Background The patent foramen ovale (PFO) and interatrial block (IAB) are associated with cryptogenic stroke (CS). However, the role of the interaction between PFO and IAB in CS remains unclear. Methods This case–control study enrolled 256 patients with CS and 156 individuals without a history of stroke or transient ischemic attack. IAB was defined as P wave duration > 120 ms. PFO was evaluated by contrast transesophageal echocardiography, and classified as no-PFO, low-risk PFO and high-risk PFO. Multiplicative and additive interaction analysis were used to assess the interaction between PFO and IAB in CS. Results Multiplicative interaction analysis unveiled a significant interaction between IAB and low-risk PFO in CS (OR for interaction = 3.653, 95% CI, 1.115–12.506; P = 0.037). Additive interaction analysis indicated that 68.4% (95% CI, 0.333–1.050; P < 0.001) of the increased risk of CS related to low-risk PFO was attributed to the interaction with IAB. The results were robust in multivariate analysis. However, but no significant multiplicative or additive interaction was observed between IAB and high-risk PFO. When stratified by IAB, high-risk PFO was associated with CS in both patients with IAB (OR, 4.186; 95% CI, 1.617–10.839; P = 0.003) and without IAB (OR, 3.476; 95% CI, 1.790–6.750; P < 0.001). However, low-risk PFO was only associated with CS in patients with IAB (OR, 2.684; 95% CI, 1.007–7.149; P = 0.048) but not in those without IAB (OR, 0.753; 95% CI, 0.343–1.651; P = 0.479). Conclusion The interaction between IAB and PFO might play an important role in CS, particularly in cases with low-risk PFO.

Keywords

• Patent foramen ovale, interatrial block, cryptogenic strokes, ischemic stroke