Watchman Left Atrial Appendage Closure Device Fares Well in Early Commercial Experience

CHICAGO, IL—In the initial experience following US approval, the Watchman left atrial appendage (LAA) closure device has had a high rate of implant success similar to that seen in the preapproval clinical studies, a new study shows.

With procedures performed by many first-time primary operators and at many centers that did not participate in the clinical trials, implant success was 95.5%, which compares with rates ranging from 90.9% in PROTECT AF to 98.5% in the European EWOLUTION registry, David Holmes, MD (Mayo Clinic, Rochester, MN), reported at the American College of Cardiology 2016 Scientific Sessions here.

Commenting on the study for TCTMD, Kenneth Ellenbogen, MD (Virginia Commonwealth University, Richmond, VA), speaking on behalf of the American Heart Association, said he was not surprised to see the high success rate maintained in the postmarket setting.

Even though Watchman clinical specialists were present for all of the cases in the current study, Ellenbogen said the results are a good indication of how Watchman will perform in real-world practice, because the procedure is relatively easy to perform and does not require extensive additional training for operators experienced in structural heart or electrophysiology procedures.

The consistency between the clinical trial and commercial results “makes you think that the procedure is ready for prime time, that it’s a good procedure with good results,” Ellenbogen said. “I don’t think there are going to be any big surprises.”

Watchman (Boston Scientific) was approved by the US Food and Drug Administration in March 2015 based on results from the PROTECT AF and PREVAIL trials and their associated registries. A postmarket surveillance study was mandated as a condition of approval, but that will not start enrolling patients until sometime in the second quarter of 2016.

Clinicians started using Watchman immediately after approval, however. The analysis presented by Holmes includes 1,683 cases entered into a procedural database by the clinical specialists accompanying procedures performed after FDA clearance. All procedures were performed by operators trained in LAA occlusion, although 70% of treating physicians had not been the primary operator before and half of procedures took place at centers that did not participate in the clinical trials of the device.

The most common anatomic shape of the LAA was windsock (43%), followed by chicken wing (19%), broccoli (18%), and other (20%). Sizes of the LAA ostium and LAA diameter, and thus the devices used, were larger in the commercial experience compared with the preapproval studies.

Although implant success, defined as successful deployment with no leak ≥ 5 mm, was high, partial device capture was needed in about one-quarter of cases because of uncertainty about the position or because criteria for release were not met. The average number of devices used per implant attempt was 1.4.

The average procedure duration was 50 minutes, ranging from 15 to 195 minutes. In preapproval studies, that figure was as low as 46 minutes in PREVAIL experienced operators and its associated registry and as high as 67 minutes in PREVAIL new operators.

There was no measurable residual jet in 97% of procedures.  

• Holmes DR, Reddy VY, Kar S, et al. Post FDA approval experience of left atrial appendage occlusion in the United States. Presented at: American College Cardiology 2016 Scientific Sessions. April 2, 2016. Chicago, IL.

Disclosures:

•  Holmes reports a conflict related to technology licensed from Mayo Clinic to Boston Scientific.
•  Ellenbogen reports serving as the co-chairperson for the LAA closure registry that will be launching in the second quarter of this year.

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