Device-Related Thrombus Studied in Boston Scientific's Watchman Left Atrial Appendage Closure Device
May 11, 2018—Boston Scientific Corporation announced the presentation of results from a pooled analysis of four studies of the Watchman left atrial appendage closure (LAAC) device during a late-breaking clinical trial session at Heart Rhythm 2018, the Heart Rhythm Society's 39th annual scientific sessions held May 9–12 in Boston, Massachusetts.
The company advised that the analysis evaluated the incidence, predictors, and outcomes of device-related thrombus (DRT) in patients treated with Watchman and demonstrated that < 1% of patients experienced DRT and a stroke. The study was simultaneously published online in Circulation by Srinivas R. Dukkipati, MD, et al.
The Watchman device is indicated for patients with nonvalvular atrial fibrillation (AF) who are at high stroke risk and are eligible to take warfarin but have a meaningful reason to seek a device alternative to reduce their risk of stroke. As many as 40% of people who are prescribed oral anticoagulant therapy do not take their medicine for a variety of reasons, putting them at a heightened risk of stroke.
According to Boston Scientific, the analysis found that 3.7% of patients had DRT at some point during the course of their follow-up. Patients with DRT had a higher incidence of stroke than patients who did not, but it was an infrequent cause of stroke as < 1% of patients had both DRT and stroke. The rate of DRT in this analysis is consistent with previously published rates and the overall risk of stroke was lower with Watchman than was expected in untreated patients.
In the company's press release, the study's Principal Investigator Vivek Reddy, MD, commented, "These data add to the wealth of clinical evidence available about the Watchman device. [DRT] is uncommon, but when it is detected, our data indicate that an appropriate anticoagulation strategy should be pursued." Dr. Reddy is Director of Cardiac Arrhythmia Services for The Mount Sinai Hospital and the Mount Sinai Health System in New York, New York.
Also at the Heart Rhythm 2018 meeting, real-world results from the European EWOLUTION registry were presented and demonstrated that the device continues to have a high implant success rate, and low rates of stroke and major bleeding in patients with nonvalvular AF, including those patients deemed unsuitable for oral anticoagulation.
Boston Scientific advised that in the United States, the Watchman device is only indicated for patients who can be treated with oral anticoagulation for a minimum of 45 days. The device is being studied in patients unable to take oral anticoagulants in the randomized ASAP TOO trial, which is currently enrolling.