MedicalResearch.com Interview with:
Prof. Jean-Louis MAS
Université Paris Descartes
INSERM UMR S 894
Service de Neurologie et Unité Neurovasculaire
MedicalResearch.com: What is the background for this study?
Response: Stroke is a major cause of death, disability and dementia affecting 17 million people each year worldwide. About 80% of strokes are ischemic strokes due to occlusion of a cerebral artery by a thrombus, itself the consequence of various arterial or heart diseases. In 30 to 40% of cases, no definite cause of ischemic stroke can be identified. Cryptogenic stroke is the term used to refer to these strokes of unknown etiology.
The patent foramen ovale (PFO) is a defect between the upper two heart chambers (called atria) though which a thrombus of venous origin may reach the systemic circulation and cause a stroke. This mechanism is called paradoxical embolism. Several case-control studies have shown an association between PFO and cryptogenic ischemic stroke, particularly in patients less than 60 years old, in those who have an atrial septal aneurysm (defined as an abnormal protrusion of the interatrial septum in the right or the left atrium or both) in addition to a PFO, and in those who have a PFO with a large right-to-left shunt. These findings suggested that a PFO might be responsible for stroke and that PFO closure with a device may decrease the risk of stroke recurrence. However, the causative relationship between PFO and stroke and the best strategy to prevent stroke recurrence have long been a hot topic of debate. Three previous randomized clinical trials failed to demonstrate any superiority of PFO closure over antithrombotic therapy.