Article Text

Download PDFPDF
Patent foramen ovale and the risk of stroke: smoking gun guilty by association?
  1. P Amarenco
  1. Correspondence to:
    Dr Pierre Amarenco
    Department of Neurology and Stroke Centre, Bichat University Hospital and Medical School, Bichat Hospital, 46 rue Henri Huchard, 75018, Paris, France;

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.

Between 15–20% of cases of brain infarction involve patients under the age of 55 years—that is, 150 000 to 200 000 patients each year in Europe. The main causes include cardiac valve disease and dissections of extracranial arteries (accounting for up to 20% of cases). In this age range, rare causes of arteriopathies may be found more frequently than in older stroke patients. Their mechanism is either inflammatory disease, infectious, metabolic, or toxic. Atherosclerosis accounts for 10% of cases. Over 150 causes of stroke have been listed. However, despite a thorough evaluation, the cause of the stroke remains unknown in up to 50–60% of cases in patients younger than 55 years.

In this group, transoesophageal echocardiography (TOE) shows inter-atrial septal abnormalities in 55–60% of cases. The same abnormal septum is observed in 20% of the normal population. However, when present in a patient with a stroke of unknown cause, is this abnormality responsible for the stroke or the marker for the true cause of stroke? For example, having yellow nails is statistically associated with lung cancer, but does not mean that yellow nails cause lung cancer.


In 1988, Lechat and colleagues1 performed transthoracic echocardiography (TTE) with contrast micro-bubble injection and showed that patients with stroke of unknown cause more frequently had PFOs than controls. Since then, numerous studies concurred with this result and have been summarised in a meta-analysis (fig 1).2

Figure 1

 Meta-analysis of case–control studies in patients with cryptogenic strokes. CI, confidence interval; OR, odds ratio.2

In a study using TOE in 100 patients and 55 controls younger than 55 years, we found that a PFO was present in 43% of patients, 56% of patients with brain infarction of unknown cause, and in only 18% of controls (odds ratio (OR) 3.9, 95% confidence interval (CI) 1.5 to …

View Full Text

Linked Articles