SWISS-APERO: a randomized trial of the amulet versus watchman FLX devices for left atrial appendage closure
The SWISS-APERO is a prospective, investigator-initiated, randomized, multi-center, and clinical trial designed to compare the Amulet and Watchman (2.5 and FLX) devices in a head-to-head fashion.
Why This Study? – The Rationale/Objective
Percutaneous left atrial appendage (LAA) closure has been established as a good alternative to oral anticoagulation in patients who cannot tolerate the pharmacological treatment. Multiple devices are currently available for LAA closure, with the Amulet and Watchman device as the most used worldwide.
These devices have been perfected in design and shape in the latest-generation devices. While a direct comparison between Amulet and the first-generation Watchman has been recently presented (AMULET IDE) a comparison between Amulet and the latest-generation Watchman FLX was still lacking.
How was it executed? – The methodology
The SWISS-APERO is a prospective, investigator-initiated, randomized, multi-center, and clinical trial designed to compare the Amulet and Watchman (2.5 and FLX) devices in a head-to-head fashion.
The study was designed to assess the superiority of the Amulet device for the primary endpoint of need for crossover to another device or complete LAA sealing, as assessed by means of cardiac computed tomography angiography (CCTA) at 45 days after implantation.
Secondary endpoints included all and major procedural complications and LAA patency assessed with transesophageal echocardiography at 45 days.
What is the main result?
A total of 221 patients were randomized to Amulet or Watchman device at 8 centers across 4 European countries.
In the Watchman group, 22.7 % had a procedure with an older-generation device (Watchman 2.5), and the rest had a procedure with the new Watchman FLX.
The primary endpoint of justified crossover to another device during the procedure or residual LAA patency as assessed by CCTA at 45 days was similar between the two devices and occurred in 67.6 % of patients assigned to Amulet compared with 70 % of those assigned Watchman (RR = 0.97; 95 % CI, 0.80-1.16; P = 0.71).
A roughly three-fold higher rate of major procedural complications was observed in the Amulet group (9 % vs. 2.7 %; P = 0.047), driven by higher rates of bleeding (7.2 % vs. 1.8 %) including pericardial bleeding. At transesophageal echocardiography assessment, LAA patency at 45 days was 13.7 % in the Amulet group compared with 27.5 % in the Watchman group (RR = 0.50; 95 % CI, 0.27-0.91; P = 0.02) although no peri-device leak greater than 5 mm were not observed in either group.
Critical reading and the relevance for the clinical practice
In this direct comparison between two LAA occlusion devices Amulet and Watchman (majority of Watchman FLX), no difference was observed for the primary endpoint of crossover and residual LAA patency.
Amulet was associated with less peridevice leaks at 45 days assessed by TEE, but with a higher rate of major periprocedural complications.
Clinical outcomes were similar between the two devices, but the study was not powered for these outcomes.
We shall remember the LAAO remains a preventive procedure focused on reducing the risk of future events. Hence, maximal periprocedural safety has outstanding importance in this setting.
While aiming at complete sealing of the left atrial appendage, future studies will give us insights on the impact of residual minimal leaks to understand their clinical relevance, also in light of the recent data confirming additional benefit from LAA closure also in association with normal dose or reduced dose anticoagulation in patients that could tolerate it.
In general, the SWISS-APERO trial provides us with a relevant first comparison of the two devices that could further inform our data-driven decision-making.
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