Completely different strengths for LAA sealing gadgets?

Based on the results, there was no clear winner from a study that directly compared two modern devices used in patients undergoing percutaneous left atrial appendage (LAA) occlusion.

According to the results of the open label SWISS APERO study, in which the Amplatzer amulet was compared with the Watchman FLX device at eight participating centers in Europe, the devices were not interchangeable due to complications or leaks.

After 45 days, the overall leak rates and clinical outcomes were not significantly different in the two randomized groups, but there were differences in the secondary endpoints such as: and procedural complications that were higher, reported Roberto Galea, MD, at the Transcatheter Cardiovascular Therapeutics Annual Meeting, held virtually and live in Orlando.

By sealing the LAA, which is the source of heart thrombi that lead to thrombotic events. LAA closure devices were developed as an alternative to oral anticoagulation in patients with non-valvular atrial fibrillation. Although a similar comparison of LAA locking devices called the Amulet IDE was recently published, this attempt compared Amulet to Watchman 2.5, an earlier generation device.

Launched later, SWISS APERO was also a planned comparison of the Amulet and the Watchman 2.5, but the comparison switched to the Watchman FLX when it was released in March 2019.

First randomized comparison with Watchman FLX

“This is the first multicenter randomized controlled trial to include the Watchman FLX,” said Galea, a clinical investigator in the cardiology department at Bern University Hospital, Switzerland. He noted that the Watchman FLX included some design adjustments with the potential to reduce leak rates.

After the pre-procedural transesophageal echocardiography had confirmed that the patients had a suitable anatomy for the use of both devices, the 221 patients who had qualified for SWISS APERO were randomized. The primary endpoint was a combination of a justified switch to a device other than the one they were assigned to or residual patency determined by coronary computed tomography angiography (CCTA) at 45 days.

The primary endpoint was met by 67.6% of patients randomized to the Amulet device and 70% of patients randomized to Watchman Flex, a statistically insignificant difference (P = 0.71).

Since only one patient in the Amulet group and none in the Watchman group had a legitimate switch to a non-randomized device, most of the differences in the 45-day CCTA concerned patency, defined as an LAA density of at least 100 Hounsfield- Units. While the proportion of patients with leaks was similar, the types of leaks that were stratified according to the underlying leak mechanism in PDL, mixed leaks (including incomplete side sealing), intradevice leaks, and leaks of unclear origin differed.

Peridevice licks twice as hard with Watchman

Those randomized to use the Watchman device were more than twice as likely to have PDL (27.5% vs. 13.7%; P = 0.02), although no visible leak exceeded 5 mm in size. They also had more frequent mixed leaks (14% vs. 3.8%; P = .01) and patency with no visible leak (21.0% vs. 9.5%; P = .02). There were also more device-related thrombi in the Watchman group, although the difference did not reach statistical significance (9.9% vs. 3.7%; P = 0.08).

Intradevice leaks (44.8% vs. 23.0%; P = 0.001) were the only type of patency that was significantly more common in patients randomized to Amulet, but the difference was relatively large. In addition, procedural complications of any kind (32.4% vs. 19.1%; p = 0.023) were higher in the Amulet group. Most of these concerned non-clinically relevant pericardial effusions, Galea said at the meeting sponsored by the Cardiovascular Research Foundation.

The proportion of patients with adverse outcomes at 45 days was similar, but the nature of the complications differed. Of the six deaths in the Amulet group, two occurred as a result of periprocedural complications (one from an air embolism and the other from a series of events following a pericardial effusion). Three of the four deaths in the Watchman group were due to fatal bleeding. The fourth was sudden death that occurred 30 days after the procedure.

Amulet IDE-Test generates similar data

The much larger Amulet IDE study that compared Amulet to the Watchman 2.5 device generally produced similar results. Again, the proportion of patients who met the composite primary endpoints was similar.

The primary safety endpoint, which included death and major bleeding within 12 months of randomization, occurred in 14.5% and 14.7% of Amulet and Watchman patients, respectively (P <0.001 for non-inferiority). The primary efficacy endpoint, which included stroke or systemic embolism within 18 months of randomization, occurred in 2.8% of patients in both groups.

As with SWISS APERO, the Amulet IDE study with 1878 patients showed that the devices are similarly effective and safe, but not necessarily interchangeable. Ultimately, the rate of LAA occlusion in Amulet was higher than in the older generation Watchman (98.9% vs. 96.8%; p = 0.003), but procedural complications were more common in the randomized patients (4.5% vs. . 2.5%).

“The occlusion mechanisms are not the same, which may explain why we see differences in some secondary endpoints even if they perform similarly on the primary endpoints,” said Dhanunjaya R. Lakkireddy, MD, executive medical director, Kansas City, Kansas Heart Rhythm Institute.

The lead researcher of the Amulet IDE study, Lakkireddy, referred to both the AMULET IDE and SWISS APERO studies when he said that currently available data does not allow one device to be superior to the other. He suggested that differences between devices might still be considered significant in certain clinical situations or to certain clinicians.

With no studies showing objective differences, Lakkireddy suggested that education and experience are likely the most important variables in achieving treatment goals. “Operator comfort is certainly important,” he said.

Galea does not report any significant financial relationships. The investigator-initiated study was funded by Abbott, the manufacturer of the amulet device. Lakkireddy has financial relationships with Abbott, AltaThera, Medtronic, Biotronik, and Boston Scientific, which manufacture the Watchman device.

This story originally appeared on MDedge.com, part of the Medscape Professional Network.