The PROOF Trial - Prospective, Open-label, Multicenter, Non-randomized Investigation on Percutaneous Patent Foramen Ovale (PFO) Closure Using the Occlutech PFO Occluder to Prevent Recurrence of Stroke in Patients With Cryptogenic Stroke and High Risk PFO

Inclusion Criteria: * Age ≥18 years and ≤65 years * At least one event of cryptogenic ischemic stroke in the last 12 months * Presence of a PFO indicated for device-assisted closure (in compliance with the Instruction for Use) confirmed by common practice procedures * A large PFO (maximum separation of the septum primum from the secundum) of ≥2 mm confirmed by common practice procedures, or an ASA defined by common practice procedures as septum primum excursion of ≥10 mm * Life expectancy of at least 1 year * Ability to speak fluently and to understand the language in which the study is being conducted * Written, informed consent by the patient for participation in the study and agreement to comply with the follow-up schedule Exclusion Criteria: * Acute infection(s) * Known coagulation disorder * Arrhythmia * Atrial Tumor * Allergies to nickel and/or titanium and/or nickel/titanium-related material * Inability to achieve adequate oral anticoagulation therapy and/or platelet inhibition post intervention * Intolerance to contrast agents * Participation in another clinical investigation \<30 days before intended Occlutech PFO Occluder implantation procedure (note that in line with Medical Device Reporting, registries are not considered as clinical investigations) * Contraindication to use of trans-esophageal echocardiography (TEE) and/or use of general anesthetic * Eisenmenger Syndrome * Recent pelvic venous thrombosis * Myocardial infarction or coronary artery bypass surgery within the last 30 days * Atrial thrombus * Patients whose size or condition would cause them to be a poor candidate for cardiac catheterization (e.g. too small for echocardiography imaging probe, catheter size, vasculature size, active infection, body weight \<8 kg) The following exclusion criteria are at the discretion of the investigator: * Stroke of any other origin * Large artery atherosclerosis * Small vessel disease * Arterial dissection * Hypercoagulable disorder * Uncontrolled hypertension * Uncontrolled diabetes * Autoimmune disease * Evidence of drug or alcohol abuse * Chronic, persistent, or paroxysmal atrial fibrillation or atrial flutter * End-stage heart-, liver-, lung-, or kidney disease * Cardiac tumor * Endocarditis or septicemia * Severe valvular pathology * Any condition that, in the opinion of the investigator, might interfere with the implantation,might affect the patients' well-being thereafter or might interfere with the conduct of the study