Evaluation od Safety and Performance of the Omega™ LAA (Left Atrial Appendage) Occluder and Omega™ Delivery System in Patients With Non-Valvular Atrial Fibrillation and High Bleeding Risk

The purpose of the study is to assess the safety and performance of the Omega™ LAA (Left Atrial Appendage) Occluder and Omega™ Delivery System in LAA (Left Atrial Appendage) closure for patients with non-valvular atrial fibrillation (NVAF) and high bleeding risk.

Omega™ LAA (Left Atrial Appendage) Occluder used in combination with the indicated Omega™ Delivery System is a permanent implant to the left atrial appendage for percutaneous insertion. LLA (Left Atrial Appendage) occlusion appears to be a feasible option for stroke reduction in AF patients at high risk for stroke, who are contraindicated for anticoagulation or who suffered a stroke despite OC. This study will evaluate safety and performance, using a study design which is based on inputs from pre-clinical testing, the risk analysis and data available from other LAA (Left Atrial Appendage) devices.

Eligibility Criteria:
Inclusion Criteria:

1. 18 years of age or older
2. Documented paroxysmal, persistent, or permanent non-valvular atrial fibrillation (AF)
3. At increased risk of stroke or systemic embolism defined as CHADS2 score (Risk of Stroke with AF". VA Palo Alto Medical Center and at Stanford University: the Sportsmedicine Program and the Cardiomyopathy Clinic: Congestive/Hypertension/Age/Diabetes/Stroke): ≥ 2 or a CHA2DS2-VASc score (Congestive/Hypertension/Age/Diabetes/Stroke/Vascular disease/Sex) ≥ 3
4. Deemed, by investigator, to be unsuitable or contraindicated for long term oral anticoagulation therapy due to high bleeding risk
5. To have suitable anatomy for percutaneous Left Atrial Appendage occlusion procedure with a single Omega™ device
6. Able and willing to comply with the required medication regimen post-device implant
7. Able to understand and willing to provide written informed consent to participate in the study
8. Able to and willing to return for required follow-up visits and examinations.

Exclusion Criteria:

1. Requires long-term oral anticoagulation therapy for any indication other than atrial fibrillation
2. Contraindicated for or allergic to aspirin/clopidogrel, warfarin or novel oral anticoagulant (NOAC) use
3. Implanted with a mechanical heart valve prosthesis thus requiring long term oral anticoagulation
4. Has any contraindications for a percutaneous catheterization procedure (e.g. subject is too small to accommodate the transoesophageal echocardiogram (TEE/TOE) probe or required catheters, or subject has active infection or bleeding disorder)
5. Women of childbearing potential who are, or plan to become, pregnant during the time of the study (method of assessment per physician discretion)
6. Stroke or transient ischemic attack (TIA) within 6 weeks prior to implant procedure
7. Underwent any cardiac or non-cardiac intervention or surgery within 30 days prior to implant, or intervention or surgery is planned within 60 days after implant procedure
8. Myocardial infarction (MI) within 90 days prior to implant
9. New York Heart Association Class IV Congestive Heart Failure
10. Left ventricular ejection Fraction (LVEF) ≤ 30%
11. Reversible cause of AF (i.e. secondary thyroid disorders, acute alcohol intoxication, trauma, recent major surgical procedures)
12. Left atrial appendage is obliterated or surgically ligated
13. Resting heart rate \>110 bpm
14. Thrombocytopenia (defined as \< 70,000 platelets/mm3) or anaemia with haemoglobin concentration of \< 10 g/dl (i.e. anaemia as determined by the investigator which would require transfusion)
15. Actively enrolled or plans to enrol in a concurrent clinical study in which the active treatment arm may confound the results of this trial
16. Active endocarditis or other infection producing bacteraemia
17. Subject has a known malignancy or other illness where life expectancy is less than 2 years
18. Impaired renal function with eGFR (Estimated Glomerular Filtration Rate) \<40 ml/min/1.73 m2
19. More than mild hepatic failure, i.e. ALT (Alanine Aminotransferase), AST (Aspartate Aminotransferase), or Alkalic Phosphatase \>2× upper limit of normal

Echocardiographic Exclusion Criteria:

1. Intracardiac thrombus - including Left Atrial Appendage - visualized by echocardiographic imaging
2. Existing circumferential pericardial effusion \>2mm
3. Significant mitral valve stenosis (i.e. mitral valve area \<1.5 cm2)
4. High risk patent foramen ovale (PFO), defined as an atrial septal aneurysm (atrial septal excursion \>15mm; excursion defined as maximal protrusion of the ASA (Atrial Septal Aneurysm) beyond the plane of the atrial septum during cardiac cycle) or large shunt (substantial passage of bubbles, i.e. ≥ 25, within 3 cardiac cycles from appearing in the right atrium)
5. Complex atheroma with mobile plaque of the descending aorta and/or aortic arch
6. Cardiac tumour
7. Left Atrial Appendage anatomy cannot accommodate an Omega™ device (as per IFU)
8. Placement of the device would interfere with any intracardiac or intravascular structure.