No significant differences between Watchman and Amplatzer in first comparison

Matteo Montorfano

Results from the first study to compare outcomes of two left atrial appendage closure devices—Watchman (Boston Scientific) and Amplatzer (St Jude Medical)—indicate that there are no significant differences between the devices. Authors Filippo Figini (Interventional Cardiology Department, San Raffaele Hospital, Milan, Italy) and others note that while the incidence of peri-device leak was significantly higher with Watchman, this finding did not translate into a difference in clinical outcomes.

Writing in Catheterization and Cardiovascular Interventions, Figini et al report that the “over the last years” percutaneous left atrial appendage closure has emerged as a possible alternative to anticoagulation and that “several devices are now available and approved for this purpose” (in Europe at least). However, they add that evidence from one device may not be applicable to another and that the studies for left atrial appendage closure devices focused on patients who were good candidates for oral anticoagulation whereas a relative contraindication to oral anticoagulation “generally represents the principal reason” to offer left atrial appendage closure in daily practice. “The aim of this study was therefore to retrospectively compare indications and clinical outcomes of two contemporary left atrial appendage percutaneous systems in a ‘real-world’ population,” the authors comment.

Of 165 patients who underwent left atrial appendage closure between 2009 and 2015 at Figini et al’s centre (San Raffaele Hospital, Milan, Italy), 99 received the Amplatzer device (the second-generation version, Amulet, in the latter part of the study) and 66 received the Watchman device. The main indication for the procedure was contraindication to anticoagulation (such as history of severe bleeding) and other reasons included development of left atrial appendage thrombus while on anticoagulation therapy and thromboembolic stroke despite adequate treatment.

According to the authors, there was a significantly higher incidence of severe peri-device leak (>3mm) with Watchman. Of 13 cases overall, nine were with Watchman and four with the Amplatzer (p=0.037 for the comparison). Furthermore, 3D transoesophageal (TEE) was used significantly more frequently with the Amplatzer device (as was preprocedural computed tomography). In a multivariate analysis, use of 3D TEE was the only independent predictor for leaks >1mm but there was also a non-significant trend with the use of the Amplatzer device. Figini et al state that interpretation of these results is complicated because of the study’s non-randomised nature—a “substantial limitation” —but they add that they can “reasonably suggest that the combination of 3D TEE and the Amplatzer could minimise the incidence of peri-device flow”.

However, at follow-up, there were no significant differences in the event rate between the two devices and the authors note “importantly, at follow-up, no associations were observed between the presence of leaks and clinical events”. Therefore, they conclude: “The use of the Amplatzer cardiac plug and 3D TEE were found to minimise the incidence of residual leaks; however, this study found no effect of small peri-device flow on clinical outcomes.”

Study author Matteo Montorfano (Interventional Cardiology Department, San Raffaele Institute, Milan, Italy) told Cardiovascular News: “Looking forward, prospective randomised studies investigating the optimal preprocedural imaging modality to work-up patients and the choice of device used are required before a specific recommendation can be made.”