Amplatzer Amulet LAA Closure Device Reduces Stroke Through 2 Years: Global Registry

PARIS, France—Left atrial appendage (LAA) occlusion with the Amplatzer Amulet (Abbott) reduces the risk of ischemic stroke in real-world use through 2 years, for the most part without the need for long-term anticoagulation, according to global registry data on more than 1,000 patients released last week at EuroPCR 2019.

The findings speak to the needs of patients who have contraindications to anticoagulation, a population not well represented in randomized trials of LAA closure, investigator David Hildick-Smith, MD (Brighton and Sussex University Hospitals, Brighton, England), told attendees.

Yet, as Hildick-Smith noted in the late-breaking trial session, serious adverse events—seen at a rate of 2.1% with Amplatzer Amulet in the first 2 years after treatment—“remain a target for reduction, given that this is an entirely preventative procedure.”

To TCTMD, Hildick-Smith described how that improvement might occur. “Part of it has to do with physician training and experience. Part of it will also [have] to do with device iteration. The ideal device will be a bit softer, it will be even more inert, and perhaps mechanisms will be made for [features like] steerable catheters or something for the difficult cases,” he suggested.

The goal is to bring that procedural risk down to 1% or less, Hildick-Smith said. This needs to happen for LAA closure “to be widely acceptable as a perfect alternative to anticoagulation,” he added, predicting that this process will likely be slow.

Amplatzer Amulet received CE Mark in Europe 6 years ago but is an investigational device in the United States.

Most on Single Antiplatelet or No Antithrombotic Drugs by 2 Years

Study investigators prospectively collected information on 1,088 patients (mean age 75.2 years; 64.5% men) who had atrial fibrillation and an “appropriate indication” for LAA occlusion, enrolling them at 61 centers between June 2015 and September 2016. Worth noting, Hildick-Smith stressed, is that the design included independent adjudication of adverse events as well as core-lab analysis of imaging results.

At baseline, patients’ mean CHA2DS2-VASc and HAS-BLED scores were 4.2 and 3.3, respectively. Almost three in 10 had had a history of stroke and 10.6% had prior TIA. Nearly three-quarters (71.7%) had previously experienced a major bleed and 82.8% had a contraindication to oral anticoagulation. Two-year follow-up data were available for 94.2%.

All but 10 of the patients (99%) who underwent attempted closure had their Amplatzer Amulet device successfully implanted. All had residual flow of 5 mm or less on transesophageal echo after their procedures. At discharge, 11.2% of patients were on an anticoagulant. By 2 years, the proportion had dropped to 6.6%. Fully 84% of patients were on either single antiplatelet therapy or no antithrombotic medications 2 years after closure.

Serious adverse events were tracked for the first 7 days and then beyond 7 days.

Early and Late Serious Adverse Events With Amplatzer Amulet

In terms of major adverse events—specifically death, stroke, embolism, BARC 3a+ bleed, device embolization, and major vascular complications—within the first 7 days, the rate was 3.6% during the index hospitalization and 0.8% after discharge.

Hildick-Smith and colleagues calculated the ischemic stroke rate to be 2.2% per year, amounting to 68% less than the predicted rate of 6.7% per year based on CHA2DS2-VASc score. The annual rate of major bleeding (BARC 3a+) was 7.2%, decreasing from 10.1% in the first year to 4.0% in the second year. Only 1.7% of the annual bleeding rate was attributed to the procedure or device.

Asked how the Amplatzer Amulet compares with other LAA closure devices, Hildick-Smith described it as “particularly well designed” in terms of being versatile and easy to implant.

“The lid that seals off the appendage completely, I think is both aesthetically [pleasing] and I think from the results clearly an advantage. The fact that this is a flat, relatively inert surface contributes to the low device-related thrombus [rate],” he commented.