Patent foramen ovale and embolic stroke "en flagrant délit".

Proof of a causal relationship between a patent fossa ovale and cryptogenic stroke has been controversial (Yasaka et al, Intern Med 2005;44:434-8). The authors identified 1 patient in whom the presence of a large migrating thrombus through a moderate-size patent fossa ovale was caught "en flagrant délit," which suggests a direct pathogenic role.