Patent Foramen Ovale Closure or Anticoagulants Versus Antiplatelet Therapy to Prevent Stroke Recurrence

Secondary prevention for stroke patients with PFO is a subject of considerable debate. Therapeutic options include antiplatelet drugs, oral anticoagulants, and transcatheter closure of the foramen. There are no published studies showing convincingly the superiority of any one of these strategies in preventing stroke recurrence. All the therapeutic options have some risks and unless randomised trials can define who should be treated with what (if anything), and for how long, we could end up exposing patients to unnecessary complications of treatment. The primary objective of this study is to assess whether chronic anticoagulation (INR 2 to 3) on the one hand and endovascular treatment on the other hand are superior to chronic antiplatelet therapy in preventing stroke recurrence in young (16 to 60 years) patients with a PFO (\> 30 microbubbles or associated with an atrial septal aneurysm) and an otherwise unexplained ischaemic stroke. Secondary objectives of the study are: * to evaluate the safety of the three therapeutic options, in terms of major drug-, device- or procedure-related complications, in order to allow a benefit/risk assessment of each therapeutic option in this population. * to assess the rate of technical success and effectiveness of endovascular procedure to treat PFO and ASA.