Sleep apnea syndrome and patent foramen ovale: a dangerous association in ischemic stroke?

Abstract

Background: The coexistence of patent foramen ovale (PFO) and sleep apnea syndrome (SAS) might be related to the pathogenesis of cryptogenic stroke (CS). We aimed to determine the prevalence of SAS in patients with cryptogenic stroke and PFO.

Methods: This is a prospective case-control study in which we included ischemic stroke patients consecutively admitted to our hospital's Acute Stroke Unit. Contrast transcranial Doppler (c-TCD) and sleep polygraphy within the first 72 h after stroke onset were performed to detect PFO and SAS. Demographic and clinical characteristics, time of stroke onset, score in the National Institute of Health Stroke Scale (NIHSS), and stroke subtype were registered.

Results: A total of 97 patients were studied. Overall, 76% were men, with a mean ± SD age of 61 ± 13 years, and an NIHSS of 5 ± 5. Subtype of stroke was cryptogenic (CS) in 28 (29%) and non-CS in 69 (71%) of patients. PFO was more frequent among patients with CS (64% vs 29%, p = 0.002) and without SAS (60% vs 32%, p = 0.013). SAS was diagnosed in 74% of the whole group, with a higher prevalence in patients with known stroke etiology (83% vs 53%, p = 0.003). Finally, the prevalence of SAS and PFO coexistence was similar in patients with or without cryptogenic stroke (25% vs 22%, p = 1), and when comparing the group of patients with cryptogenic wake-up stroke to the other stroke patients (43% vs 21%, p = 0.35).

Conclusions: According to our results, there is no evidence of an association of PFO and SAS in the pathogenesis of cryptogenic stroke.

Keywords: Ischemic stroke; Patent foramen ovale; Sleep apnea syndrome.