title: Identification of patent foramen ovale permitting paradoxic embolism.
abstract: OBJECTIVE
  We sought to analyze the morphologic and functional characteristics of the patent foramen ovale in patients with different clinical likelihoods for paradoxic embolism.
  
  
  BACKGROUND
  The incidence of patent foramen ovale is increased in patients with otherwise unexplained arterial ischemic events. Because signs of venous thrombosis are absent in most patients, the diagnosis of paradoxic embolism is often questioned, even when patent foramen ovale is the only potential explanation for the ischemic event.
  
  
  METHODS
  Seventy-eight patients with a patent foramen ovale detected by contrast transesophageal echocardiography were studied: 21 patients with an otherwise unexplained arterial ischemic event and clinical evidence implying paradoxic embolism (group I), 30 patients with an unexplained ischemic event but no clinical evidence for paradoxic embolism (group II) and 27 patients without an ischemic event (group III).
  
  
  RESULTS
  During transesophageal contrast echocardiography, patients in group I had more severe right to left shunting (mean +/- SD 52 +/- 16% of the left atrial area filled with contrast medium) and a wider opening of the patent foramen ovale (7.1 +/- 3.6-mm separation between the septum primum and the septum secundum) than did patients in group II (35 +/- 15% and 4.4 +/- 3.2 mm, respectively, p < 0.001) or group III (23 +/- 12% and 3.0 +/- 2.0 mm, respectively, p < 0.001). The incidence of atrial septal aneurysm was similar in the three groups. Severe contrast shunting (> or = 50% of the left atrial area filled with contrast medium) and wide opening of the patent foramen ovale (> or = 5-mm separation) revealed a high sensitivity (71% and 86%, respectively) and high specificity (86% and 96%, respectively) for identification of group I patients.
  
  
  CONCLUSIONS
  Right to left contrast shunting is more severe and opening of the patent foramen ovale is larger in patients with ischemic arterial events considered to be due to paradoxic embolism. In patients with a patent foramen ovale as the only potential cause for ischemic events and no signs of venous thrombosis, morphologic and functional variables assessed by transesophageal echocardiography may be helpful in estimating the likelihood of paradoxic embolism.
authors.affiliation: Department of Internal Medicine, Hannover Medical School, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Hausmann
authors.forename: A
authors.initials: A
authors.lastname: Mügge
authors.forename: W G
authors.initials: WG
authors.lastname: Daniel
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D002561:Cerebrovascular Disorders / Q000209:etiology*; D003287:Contrast Media; D004452:Echocardiography; D017548:Echocardiography, Transesophageal / Q000379:methods*; D004617:Embolism / Q000209:etiology*; D005260:Female; D005500:Follow-Up Studies; D005780:Gelatin / Q000031:analogs & derivatives; D006344:Heart Septal Defects, Atrial / Q000150:complications* / Q000000981:diagnostic imaging* / Q000453:epidemiology; D006801:Humans; D002546:Ischemic Attack, Transient / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity; D013997:Time Factors
chemical_list: D003287:Contrast Media; D005780:Gelatin; C002803:oxypolygelatine