Relation between directly detected patent foramen ovale and ischemic brain lesions in sport divers

Background: In divers, the significance of a patent foramen ovale and its potential relation to paradoxical gas emboli remain uncertain. Objective: To assess the prevalence of symptoms of decompression illness and ischemic brain lesions in divers with regard to the presence of a patent foramen ovate. Design: Retrospective cohort study. Setting: University hospital and three diving clubs in Switzerland. Participants: 52 sport divers and 52 nondiving controls. Measurements: Prevalence of self-reported decompression events, patent foramen ovale on contrast transesophageal echocardiography, and ischemic brain lesions on magnetic resonance imaging. Results: The risk for decompression illness events was 4.5-fold greater in divers with patent foramen ovate than in divers without patent foramen ovale (risk ratio, 4.5 [95% CI, 1.2 to 18.0]; P = 0,03), Among divers, 1.23 +/- 2.0 and 0.64 +/- 1.22 ischemic brain lesions per person (mean +/- SD) were detected in those with and those without patent foramen ovale, respectively. Among controls, 0.22 +/- 0.44 and 0.12 +/- 0.63 lesion per person were detected (P < 0.001 for all groups). Conclusions: Regardless of whether a diver has a patent foramen ovale, diving is associated with ischemic brain lesions.