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Assessment of WATCHMAN™ Device in Patients Unsuitable for Oral Anticoagulation (ASAP-TOO)

Research area:
Principal investigator:
James Choi, MD
Type of study:

Study synopsis:
The ASAP-TOO study is a prospective, randomized, multi-center, global investigation to establish the safety and effectiveness of the WATCHMAN Left Atrial Appendage Closure Device for subjects with non-valvular atrial fibrillation who are deemed not suitable for anti-coagulation therapy to reduce the risk of stroke. Subjects are randomized in a ratio of 2 Device to 1 Control to receive the WATCHMAN LAA closure device or the control treatment of single antiplatelet medication or no medication at the discretion of the study physician (Control). All randomized subjects will follow the protocol required tests and assessments at each scheduled follow-up visit.

“The ASAP-TOO trial is a new ongoing actively enrolling study which looks at the use of a Left Atrial Appendage (LAA) closure technique in atrial fibrillation (AFib) patients who cannot take anticoagulation at all. These are patients who potentially may derive the greatest stroke prevention benefit from LAA closure. LAA closure is a relatively new procedure which reduces the risk of stroke in patients with AFib. The device being studied is currently the only FDA approved device for this use in the USA. In particular, when compared against anticoagulation with Coumadin, LAA closure with this device reduces the risk of severe debilitating stroke. Currently LAA closure with the device is primarily used in those patients with AFib who cannot take long term anticoagulation for various reasons, usually bleeding. Typically, participants in the study will be required to be on anticoagulation for at least 45 days after device implantation.” Dr. James Choi, principal investigator

Study objective:
The study will compare participants with atrial fibrillation and who are unsuitable for anticoagulation treated with the WATCHMAN LAAC device implant (including modified post-implant drug regimen) to those who a treated with single antiplatelet therapy or no therapy at the discretion of the study physician. The primary seven-day device/procedural safety endpoint is the combined rate of death, ischemic stroke, systemic embolism and complications requiring major cardiovascular or endovascular intervention. The primary efficacy endpoint is the comparison of time to first event of ischemic stroke and systemic embolism.

Main/critical inclusion and exclusion criteria: A complete list of inclusion and exclusion criteria can be found at

Study contact:
Jennifer Cruthis,, 214.820.3319

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