• March 2018

    ASAP-TOO Trial Implants WATCHMAN™ LAAC Device Without Post-Procedure Anticoagulation Therapy

To reduce the risk of stroke, the WATCHMAN™ left atrial appendage closure (LAAC) device has provided an additional option for some patients with non-valvular atrial fibrillation who are not good candidates for long-term anticoagulation therapy. Now, studies are underway to investigate the effectiveness of this device in a wider patient pool.

WATCHMAN™ device

The WATCHMAN™ device, which reduces the risk of stroke by sealing off the area of the heart where stroke-causing clots are most likely to form, has been proven to be as effective as anticoagulation therapy in AFib patients. However, current FDA labeling requires patients to still receive anticoagulants for a short period of time – a minimum of 45 days – following device implantation.


To potentially offer the device to candidates who cannot receive anticoagulants post-procedure, Baylor Scott & White The Heart Hospital – Plano is enrolling patients in a new clinical trial – Assessment of the WATCHMAN™ Device in Patients Unsuitable for Oral Anticoagulation (ASAP-TOO​).

​“The ASAP-TOO trial extends investigation of the device to a very important group – those who cannot take oral anticoagulation at all,” said Steven Kindsvater, MD, an interventional cardiologist on the medical staff and Vice Chairman of Cardiovascular Medicine at Baylor Scott & White The Heart Hospital – Plano, who is principal investigator for the study.

During the multicenter study, participants will be randomized with a ratio of two receiving the WATCHMAN™ device with no follow-up anticoagulation therapy to one receiving control treatment of single antiplatelet medication or no medication at the discretion of the study physician. Participants will be followed for a period of five years to track the occurrence of stroke, systemic embolism, cardiovascular or endovascular intervention, or death.

Potential Candidates

Potential study participants may include AFib patients who are unable to take anticoagulants for any period of time, such as those with a history of recurrent gastrointestinal bleeding or intracranial bleeding, as well as individuals on aspirin therapy only because of a high risk of falling or prior falls.

“We know that aspirin and antiplatelet therapy are not effective for stroke prevention,” Dr. Kindsvater said. “Therefore, this is a group of individuals that is greatly undertreated. Many patients are simply not on any type of therapy and are not currently being considered for advanced therapies like left atrial appendage closure.”

If proven effective, the WATCHMAN™ device could become an option for this group of patients who previously have not had an alternative for stroke risk reduction. Through studies like ASAP-TOO, thousands of additional AFib patients may be eligible for left atrial appendage occlusion device implantation.

“Left atrial appendage closure is underutilized in the United States,” Dr. Kindsvater said. “Just looking at the population in Dallas-Fort Worth, there are approximately 10,000 to 15,000 candidates who could receive left atrial appendage closure for stroke prevention who are currently undertreated.”

Team Approach

The ASAP-TOO trial is one piece of a dedicated program for left atrial appendage closure at Baylor Scott & White Heart – Plano. Through a structured heart team approach, the hospital’s left atrial appendage closure program brings together multiple physicians to review each patient for inclusion in appropriate commercial or research options.

The hospital was one of the first sites to implant the WATCHMAN™ device and has seen increasing patient volumes in the last year. Physicians on the medical staff are also involved in other research in the area of left atrial appendage closure devices. As this continues, the devices have the potential to become a routine treatment option in AFib patients.

“It takes time to adopt new technology and new therapies,” Dr. Kindsvater said. “However, just as transcatheter aortic valve replacement has become a commonly accepted treatment for aortic valve stenosis, we will increasingly find that left atrial appendage closure is going to be a commonly accepted treatment for stroke prevention in AFib patients.”

If you have an AFib patient who may be a candidate for the ASAP-TOO trial, contact the ASAP-TOO research coordinator at 469.814.4878 or Destiny.Barnett@BSWHealth.org​​ to learn more about eligibility criteria.

Contributing Authors

Steven Kindsvater, MD
Vice Chairman, Cardiovascular Medicine
Baylor Scott & White The Heart Hospital Baylor – Plano