Antithrombotic Therapy After Left Atrial Appendage Occlusion: Double Antiplatelet Therapy vs Apixaban

Detailed Summary

Objective: To demonstrate superiority of a strategy of anticoagulation with apixaban 5mg/2.5mg bid as compared with the current standard of care (dual antiplatelet therapy) after occlusion of the left atrial appendage (LAAC) in patients with atrial fibrillation (AF). Rationale: Data on antithrombotic therapy after LAAC are scarce and no randomized evaluation has been performed to demonstrate what is the best antithrombotic strategy. LAAO in patients without contraindication to chronic anticoagulants (PROTECT-AF regimen) is a 6-week period of anticoagulation with warfarin associated with aspirin, followed by once daily clopidogrel (75 mg) and aspirin (81-325 mg) until the 6 months visit, then aspirin alone is continued indefinitely, as tested in the pivotal trials. LAAO is also being used as an alternative to warfarin anticoagulation when patients have a contraindication or are unsuitable to warfarin. These patients usually receive a regimen of daily clopidogrel and aspirin (DAPT) for 3 months. Some may receive a shorter duration of DAPT or even only single antiplatelet therapy (SAPT) in case of excess bleeding risk. This antiplatelet regimen has never been compared with any anticoagulation regimen after LAAC. The Investigators propose to evaluate a unique antithrombotic strategy after LAAC for atrial fibrillation, whatever the indication of LAAC, including patients not suitable for long term warfarin anticoagulation. This strategy uses apixaban 5mg (with dose adjustment when necessary) which will be compared to the standard of care based on antiplatelet therapy and which may vary according to the risk profile of the patient. Apixaban, has demonstrated a mortality benefit associated with significant reductions in stroke, systemic embolism and major bleeding versus VKA. In addition, apixaban is the only NOAC which has demonstrated superiority over aspirin alone, in AF patients not suitable for chronic warfarin anticoagulation, to prevent cardio-embolic events with a safety profile similar to aspirin.The Investigators therefore formulate the hypothesis that apixaban is superior to standard of care (APT) to prevent cardiovascular events and bleeding complications after LAAO. Population: Inclusion criteria: AF patients who have undergone a successful LAAO procedure. Exclusion criteria include any indication for triple antithrombotic treatment, mechanical heart valve, use of prasugrel or ticagrelor, serious renal failure defined as a creatinine clearance \<15mL/min, contraindication to any form of anticoagulation or antiplatelet therapy. Randomization will occur always before hospital discharge as soon as the patient is stable or stabilized after the procedure. Randomization: Apixaban vs. APT, both for 3 months. Groups: 1/Apixaban 5mg or 2.5mg bid (if dose adjustment needed). 2/ DAPT using low-dose ASA (75-100mg) and clopidogrel (75mg); or in patients with a history of intracranial hemorrhage (ICH) SAPT (aspirin or clopidogrel) will be used instead of DAPT from the time of randomization. Follow-up: 12 months from randomization Primary endpoint: combined enpoint of death, MI, stroke, thromboembolic complications, major or significant bleeding at 3 months follow-up. Sample size: In order to find a 16% difference in the event rates among the two treatment strategies, using a logrank test with a 5% two-sided significance level, we will need 76 patients in each group (152 in total). However, to compensate patient drop out, a total of 160 patients will be included in the study. Recruitment : 24 months Centers: 3 centers in Spain.

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