Facing the lack of recommandations of Neurology and cardiology societies, the investigators decided in 2002 some Good Medical Practices to define a specific and precise population for whom the closure of permeable oval formaen after a first CVA seem to be necessary. Current survey of these patients after implantation of a prothesis in interauricular septum is defined by a consultation at 1, 3 and 6 months after surgery for a clinical exam and an echocardiography. One year after implantation, the investigators systematically realized a control by MRI associated to a contrast echography.

In the aim of evaluating the investigators' medical practice, the investigators decided to do an observational study which will permit us to judge of the interest or lack of interest of our "Good medical practice" before the publication of prospective and randomised clinical studies.

Inclusion Criteria:

• less than 55 years old
• occlusion of FOP after cryptogenic CVA

Exclusion Criteria:

• characterized thromboembolic event
• patients who have a surgery after transitory ischemic accident

patient who had an occlusion of POF after CVA, younger than 55 years and without thromboembolic events.