Aspirin Discontinuation After Left Atrial Appendage Occlusion in Atrial Fibrillation (ASPIRIN-LAAO)

The ASPIRIN LAAO trial is a prospective, multi-center, randomized, double blinded, placebo-controlled study aiming at investigating the safety of terminating the use of aspirin after left atrial appendage occlusion (LAAO). Patients diagnosed with atrial fibrillation and have undergone LAAO will be enrolled in this study. Randomization will be performed at 6 months post-implant. The randomization program electronically assigns the patient 1:1 to either the Aspirin group or the control group. Study patients assigned to Aspirin group will receive enteric coated aspirin (100 mg/day). The control group receives placebo. After the randomization, subjects of both groups will have follow-up visits at 6 and 12 months and then every 12 months until 24 months after the last patient recruitment. For each group, 560 patients will be included, with an estimated total number of 1120 participants in this clinical study. Patients will be followed up until 24 months after the last enrollment. The primary endpoint is a composite consisting of stroke, systemic embolism, cardiovascular or unexplainable death, acute coronary syndrome, coronary artery disease or periphery vascular disease requiring revascularization and major bleeding. The secondary endpoints are all-cause death, device related thrombus, minor bleeding and rehospitalization due to heart failure.

The ASPIRIN LAAO trial is a prospective, multi-center, randomized, double blinded, placebo-controlled study aiming at investigating the safety of terminating the use of aspirin since the sixth month after LAAO. Patients diagnosed with paroxysmal or persistent atrial fibrillation with an age between 18 and 90 years and have undergone LAAO will be enrolled in this study. Randomization will be performed at 6 months post-implant. The randomization program electronically assigns the patient 1:1 to either the Aspirin group or the control group. Study patients assigned to Aspirin group will receive enteric coated aspirin (100 mg/day). The control group receives placebo. After the randomization, subjects of both groups will have follow-up visits at 6 and 12 months and then every 12 months until 24 months after the last patient recruitment. For each group, 560 patients will be included, with an estimated total number of 1120 participants in this clinical study. Patients will be followed up until 24 months after the last enrollment. The primary endpoint is a composite consisting of stroke, systemic embolism, cardiovascular or unexplainable death, acute coronary syndrome, coronary artery disease or periphery vascular disease requiring revascularization and major bleeding. The secondary endpoints are all-cause death, device related thrombus, minor bleeding and rehospitalization due to heart failure.

A stroke is a medical condition in which poor blood flow to the brain results in cell death. There are two main types of stroke: ischemic, due to lack of blood flow, and hemorrhagic, due to bleeding. They result in part of the brain not functioning properly. Signs and symptoms of a stroke may include an inability to move or feel on one side of the body, problems understanding or speaking, dizziness, or loss of vision to one side. If symptoms last less than one or two hours it is known as a transient ischemic attack (TIA) or mini-stroke. A hemorrhagic stroke may also be associated with a severe headache. The symptoms of a stroke can be permanent. Brain computed tomography or MRI may help diagnose stroke.

An embolism is the lodging of an embolus, a blockage-causing piece of material, inside a blood vessel. The embolus is usually a blood clot (thrombus). An embolism can cause partial or total blockage of blood flow in the affected vessel. An embolism in which the embolus is a piece of thrombus is called a thromboembolism. An embolism is usually a pathological event, i.e., accompanying illness or injury. Sometimes it is created intentionally for a therapeutic reason, such as to stop bleeding or to kill a cancerous tumor by stopping its blood supply. Embolism can be classified as to where it enters the circulation either in arteries or in veins. Arterial embolism are those that follow and, if not dissolved on the way, lodge in a more distal part of the systemic circulation.

Cardiovascular deaths refer to deaths due to heart dysfunction, injury of cardiac structure, coronary artery diseases and lethal arrhythmias or sudden death that cannot be explain. Cardiovascular deaths can be diagnosed with clinical symptoms or from the results of diagnostic examinations.

Major bleedings refer to the heavy bleedings of the mains organs of the body, usually include intracranial bleeding and gastrointestinal bleeding et al.. Brain computed tomography and gastrointestinal endoscope are the common approaches for diagnosing major bleedings.

Acute coronary syndrome is a syndrome (set of signs and symptoms) due to decreased blood flow in the coronary arteries such that part of the heart muscle is unable to function properly or dies. The most common symptom is chest pain, often radiating to the left shoulder or angle of the jaw, crushing, central and associated with nausea and sweating. Many people with acute coronary syndromes present with symptoms other than chest pain, particularly, women, older patients, and patients with diabetes mellitus. Acute coronary syndrome is commonly associated with three clinical manifestations, named according to the appearance of the electrocardiogram (ECG): ST elevation myocardial infarction (STEMI, 30%), non-ST elevation myocardial infarction (NSTEMI, 25%), or unstable angina (38%). There can be some variation as to which forms of myocardial infarction (MI) are classified under acute coronary syndrome.

Conronary or periphery artery diseases, regardless stable or not, need revascularization by stent which require long-term aspirin therapy

This refers to the thrombus that is related to the implantation of the device for left atrial appendage closure. Transesophageal echocardiography is effective in identifying and diagnosing device-related thrombus.

Patients need to receive treatments in hospital because of occurrence of heart failure or deterioration of heart failure.

Inclusion Criteria: Age between 18 and 90 years Paroxysmal, persistent, long-standing persistent or permanent nonvalvular AF Have already had a Watchman LAAO device implanted 6 months ago Exclusion Criteria: Clinical Exclusion Criteria Long-term aspirin therapy required Including coronary artery disease, symptomatic carotid disease, prior myocardial infarction, strokes or systemic embolism, etc Contraindicated for aspirin therapy Including active peptic ulcer, thrombocytopenia or anemia, etc. Uncontrolled malignant tumor Abnormal liver, renal or coagulation function Pregnant or pregnancy is planned during the course of the investigation Terminal illness with life expectancy <1 year Enrolled in another IDE or IND investigation of a cardiovascular device or an investigational drug TEE Exclusion Criteria* Peri-device leak >5mm Device-related thrombus Other intracardiac thrombus

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