title: Recurrent stroke and patent foramen ovale: a systematic review and meta-analysis.
abstract: OBJECTIVE
  Recurrent cerebrovascular events are frequent in medically treated patients with patent foramen ovale (PFO), but it still remains unclear whether PFO is a causal or an incidental finding. Further uncertainty exists on whether the size of functional shunting could represent a potential risk factor. The aim of the present study was to evaluate if the presence of PFO is associated with an increased risk of recurrent stroke or transient ischemic attack and to investigate further if this relationship is related to the shunt size.
  
  
  METHODS
  We conducted a systematic review and meta-analysis according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines of all available prospective studies reporting recurrent cerebrovascular events defined as cryptogenic stroke and transient ischemic attacks in medically treated patients with PFO diagnosed by echocardiography or transcranial sonography.
  
  
  RESULTS
  We identified 14 eligible studies including a total of 4251 patients. Patients with stroke with PFO did not have a higher risk of the combined outcome of recurrent stroke/transient ischemic attack (risk ratio=1.18; 95% confidence interval=0.78-1.79; P=0.43) or in the incidence of recurrent strokes (risk ratio =0.85; 95% confidence interval=0.59-1.22; P=0.37) in comparison with stroke patients without PFO. In addition, PFO size was not associated with the risk of recurrent stroke or transient ischemic attack. We also documented no evidence of heterogeneity across the included studies.
  
  
  CONCLUSIONS
  Our findings indicate that medically treated patients with PFO do not have a higher risk for recurrent cryptogenic cerebrovascular events, compared with those without PFO. No relation between the degree of PFO and the risk of future cerebrovascular events was identified.
authors.affiliation: From the Department of Neurology, School of Medicine, University of Ioannina, Ioannina, Greece (A.H.K., S.G.); Stroke Prevention and Atherosclerosis Research Centre, Robarts Research Institute, University of Western Ontario, London, Ontario, Canada (J.D.S., C.B.); Second Department of Cardiology (J.P., A.F.) and Second Department of Neurology (K.V., G.T.), Attikon Hospital, School of Medicine, University of Athens, Athens, Greece; Stroke Unit, Department of Neurology, Brugmann University Hospital, Brussels, Belgium (A.S.); and Department of Neurology, International Clinical Research Center, St. Anne's University Hospital in Brno, Brno, Czech Republic (G.T.).
authors.forename: Aristeidis H
authors.initials: AH
authors.lastname: Katsanos
authors.affiliation: From the Department of Neurology, School of Medicine, University of Ioannina, Ioannina, Greece (A.H.K., S.G.); Stroke Prevention and Atherosclerosis Research Centre, Robarts Research Institute, University of Western Ontario, London, Ontario, Canada (J.D.S., C.B.); Second Department of Cardiology (J.P., A.F.) and Second Department of Neurology (K.V., G.T.), Attikon Hospital, School of Medicine, University of Athens, Athens, Greece; Stroke Unit, Department of Neurology, Brugmann University Hospital, Brussels, Belgium (A.S.); and Department of Neurology, International Clinical Research Center, St. Anne's University Hospital in Brno, Brno, Czech Republic (G.T.).
authors.forename: J David
authors.initials: JD
authors.lastname: Spence
authors.affiliation: From the Department of Neurology, School of Medicine, University of Ioannina, Ioannina, Greece (A.H.K., S.G.); Stroke Prevention and Atherosclerosis Research Centre, Robarts Research Institute, University of Western Ontario, London, Ontario, Canada (J.D.S., C.B.); Second Department of Cardiology (J.P., A.F.) and Second Department of Neurology (K.V., G.T.), Attikon Hospital, School of Medicine, University of Athens, Athens, Greece; Stroke Unit, Department of Neurology, Brugmann University Hospital, Brussels, Belgium (A.S.); and Department of Neurology, International Clinical Research Center, St. Anne's University Hospital in Brno, Brno, Czech Republic (G.T.).
authors.forename: Chrysi
authors.initials: C
authors.lastname: Bogiatzi
authors.affiliation: From the Department of Neurology, School of Medicine, University of Ioannina, Ioannina, Greece (A.H.K., S.G.); Stroke Prevention and Atherosclerosis Research Centre, Robarts Research Institute, University of Western Ontario, London, Ontario, Canada (J.D.S., C.B.); Second Department of Cardiology (J.P., A.F.) and Second Department of Neurology (K.V., G.T.), Attikon Hospital, School of Medicine, University of Athens, Athens, Greece; Stroke Unit, Department of Neurology, Brugmann University Hospital, Brussels, Belgium (A.S.); and Department of Neurology, International Clinical Research Center, St. Anne's University Hospital in Brno, Brno, Czech Republic (G.T.).
authors.forename: John
authors.initials: J
authors.lastname: Parissis
authors.affiliation: From the Department of Neurology, School of Medicine, University of Ioannina, Ioannina, Greece (A.H.K., S.G.); Stroke Prevention and Atherosclerosis Research Centre, Robarts Research Institute, University of Western Ontario, London, Ontario, Canada (J.D.S., C.B.); Second Department of Cardiology (J.P., A.F.) and Second Department of Neurology (K.V., G.T.), Attikon Hospital, School of Medicine, University of Athens, Athens, Greece; Stroke Unit, Department of Neurology, Brugmann University Hospital, Brussels, Belgium (A.S.); and Department of Neurology, International Clinical Research Center, St. Anne's University Hospital in Brno, Brno, Czech Republic (G.T.).
authors.forename: Sotirios
authors.initials: S
authors.lastname: Giannopoulos
authors.affiliation: From the Department of Neurology, School of Medicine, University of Ioannina, Ioannina, Greece (A.H.K., S.G.); Stroke Prevention and Atherosclerosis Research Centre, Robarts Research Institute, University of Western Ontario, London, Ontario, Canada (J.D.S., C.B.); Second Department of Cardiology (J.P., A.F.) and Second Department of Neurology (K.V., G.T.), Attikon Hospital, School of Medicine, University of Athens, Athens, Greece; Stroke Unit, Department of Neurology, Brugmann University Hospital, Brussels, Belgium (A.S.); and Department of Neurology, International Clinical Research Center, St. Anne's University Hospital in Brno, Brno, Czech Republic (G.T.).
authors.forename: Alexandra
authors.initials: A
authors.lastname: Frogoudaki
authors.affiliation: From the Department of Neurology, School of Medicine, University of Ioannina, Ioannina, Greece (A.H.K., S.G.); Stroke Prevention and Atherosclerosis Research Centre, Robarts Research Institute, University of Western Ontario, London, Ontario, Canada (J.D.S., C.B.); Second Department of Cardiology (J.P., A.F.) and Second Department of Neurology (K.V., G.T.), Attikon Hospital, School of Medicine, University of Athens, Athens, Greece; Stroke Unit, Department of Neurology, Brugmann University Hospital, Brussels, Belgium (A.S.); and Department of Neurology, International Clinical Research Center, St. Anne's University Hospital in Brno, Brno, Czech Republic (G.T.).
authors.forename: Apostolos
authors.initials: A
authors.lastname: Safouris
authors.affiliation: From the Department of Neurology, School of Medicine, University of Ioannina, Ioannina, Greece (A.H.K., S.G.); Stroke Prevention and Atherosclerosis Research Centre, Robarts Research Institute, University of Western Ontario, London, Ontario, Canada (J.D.S., C.B.); Second Department of Cardiology (J.P., A.F.) and Second Department of Neurology (K.V., G.T.), Attikon Hospital, School of Medicine, University of Athens, Athens, Greece; Stroke Unit, Department of Neurology, Brugmann University Hospital, Brussels, Belgium (A.S.); and Department of Neurology, International Clinical Research Center, St. Anne's University Hospital in Brno, Brno, Czech Republic (G.T.).
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Voumvourakis
authors.affiliation: From the Department of Neurology, School of Medicine, University of Ioannina, Ioannina, Greece (A.H.K., S.G.); Stroke Prevention and Atherosclerosis Research Centre, Robarts Research Institute, University of Western Ontario, London, Ontario, Canada (J.D.S., C.B.); Second Department of Cardiology (J.P., A.F.) and Second Department of Neurology (K.V., G.T.), Attikon Hospital, School of Medicine, University of Athens, Athens, Greece; Stroke Unit, Department of Neurology, Brugmann University Hospital, Brussels, Belgium (A.S.); and Department of Neurology, International Clinical Research Center, St. Anne's University Hospital in Brno, Brno, Czech Republic (G.T.). tsivgoulisgiorg@yahoo.gr.
authors.forename: Georgios
authors.initials: G
authors.lastname: Tsivgoulis
mesh_terms: D054092:Foramen Ovale, Patent / Q000175:diagnosis / Q000453:epidemiology* / Q000628:therapy*; D006801:Humans; D011446:Prospective Studies; D012008:Recurrence; D012307:Risk Factors; D020521:Stroke / Q000175:diagnosis / Q000453:epidemiology* / Q000628:therapy*
keywords: foramen ovale, patent; ischemic attack, transient; stroke; transcranial Doppler ultrasonography; transesophageal echocardiography