Comparing PFO Outcomes of the Occlutech Flex II PFO Occluder to Standard of Care PFO Occlusion

Inclusion Criteria: Subjects with a PFO and cryptogenic stroke:

• PFO defined as visualization of microbubbles (during Trans Esophageal Echo (TEE)) inthe left atrium within three cardiac cycles of right atrial opacification at restand/or with Valsalva.

• Cryptogenic stroke defined as a stroke of unknown cause.

• Stroke defined as an acute focal neurological deficit, presumed to be due to focalischemia, and either:

• Symptoms persisting ≥24 hours OR

• Symptoms persisting <24 hours with Magnetic Resonance Imaging (MRI) or ComputerTomography (CT) findings of a new, neuroanatomically relevant, cerebral infarct.

Exclusion Criteria:

• Age < 18 years

• Myocardial Infarction (MI) or unstable angina within 6 months.

• Severe mitral valve stenosis, severe aortic valve stenosis, or severe regurgitation.

• Left Ventricle Ejection Fraction (LVEF) <35%.

• Uncontrolled hypertension or diabetes mellitus despite medications.

• Subjects contraindicated for aspirin or clopidogrel.

• Presence of other comorbid conditions, or other medical, social, or psychologicalconditions that, in the investigator's opinion, could limit the subject's ability toparticipate in the clinical trial or to comply with follow up requirements, orimpact the scientific soundness of the clinical trial results.

• Qualifying stroke with Modified Rankin score >3.

• Anatomy in which the device would interfere with intracardiac or vascularstructures.

• Life expectancy < 2 years.

• Participation in another clinical study that can interfere with the results of thisstudy

• Exclusion for patients with known causes of ischemic stroke:

• Atrial fibrillation/atrial flutter (chronic or intermittent).

• Left Ventricle (LV) aneurysm, intracardiac thrombus, or tumor.

• Mitral or aortic valve vegetation or prosthesis.

• Aortic arch plaques protruding >4 mm into the lumen.

• Atherosclerosis or arteriopathy of intra- or extracranial vessels with >50% diameterstenosis in the artery supplying the infarcted territory.

• Another cause of right-to-left shunting (e.g., an Atrial Septal Defect (ASD) or afenestrated atrial septum).

• Presence of an arterial hypercoagulable state.

• Lacunar infarct probably due to intrinsic small vessel as the qualifying event,defined as an ischemic stroke in the distribution of a single, small deeppenetrating vessel in a patient with any of the following:

• A history of hypertension (except in the first week post stroke).

• A history of diabetes mellitus.

• Age ≥50 years.

• MRI or CT with leukoaraiosis greater than symmetric, well-defined periventricularcaps, or bands (European Task Force on Age-Related White Matter Changes rating scalescore >0).

• Arterial dissection as the qualifying event.