title: Cryptogenic stroke and patent foramen ovale: matched cohorts in observational studies remain matched.
authors.forename: David
authors.initials: D
authors.lastname: Hildick-Smith
authors.forename: Bernhard
authors.initials: B
authors.lastname: Meier
mesh_terms: D005500:Follow-Up Studies; D054092:Foramen Ovale, Patent / Q000150:complications* / Q000175:diagnosis; D006801:Humans; D045423:Microbubbles; D012008:Recurrence; D012307:Risk Factors; D020521:Stroke / Q000453:epidemiology*; D014636:Valsalva Maneuver