Amulet device for left atrial appendage occlusion does not lead to greater thrombus formation

There seems to be no heightened risk of device-related thrombus formation when using the second-generation Amplatzer Amulet occluder, according to a recent study.

“In this multicentre study, the rate of [device-related thrombus] after [left atrial appendage occlusion (LAAO)] with the Amulet device was low and similar to those from the largest registries,” said researchers. “Importantly, no patient experienced a device-related thromboembolic event during follow-up.”

Thirty-eight patients (mean age, 75.8±7.7 years; 76.3 percent male) underwent LAAO primarily due to serious bleeding without a curable cause (86.8 percent; n=33). All procedures achieved technical and procedural success and majority (68.4 percent; n=26) achieved optimal device placement, as assessed by expert consensus. [Heart Lung Circ 2019;28:1683-1688]

Three cases of groin haematoma representing minor bleeding were reported, resulting in an overall rate of 7.9 percent. None required surgical intervention.

Only one patient was positive for device-related thrombus, with resultant event rate of 2.6 percent. This patient was 70 years of age and had permanent atrial fibrillation. The occurrence of stroke despite an oral anticoagulation regimen was the primary indication for LAAO. This patient achieved optimal device placement.

The thrombus diagnosis was made during the systematic trans-oesophageal echocardiography (TEE) procedure at 90 days, after which lifelong oral anticoagulation was resumed. TEE 4 weeks later showed no evidence of residual device-related thrombus.

Five other patients (13.2 percent) showed residual leaks >3 mm but <5 mm on TEE. None showed evidence of peridevice leakage >5mm, pericardial effusion and device migration.

Overall, the procedure and device turned out to be safe. No patient experienced stroke from the implantation procedure to the TEE follow-ups and none presented with thromboembolic events following LAAO. No procedure-related deaths were reported. All findings were recorded over a mean follow-up of 15 months.

“LAAO is increasingly being used for stroke prevention in patients with AF who are considered unsuitable for lifelong oral antithrombotic treatment; or as an alternative to oral anticoagulant treatment in the US,” said the researchers. The Amulet device is one of the most popular devices for this type of intervention.

“The Amulet device was designed to better exclude the LAA while limiting device-related thrombogenesis,” they explained. The present study showed that this second-generation device does not come with a significant thrombus risk and may be safe for clinical use.

Several important limitations, however, must be taken note of. Chief among these were the lack of head-to-head comparison with a first-generation device and the failure to perform late imaging to detect potential thrombus events after cessation of antiplatelet therapy. Other limitations were its observational, retrospective design and small sample size.

“Larger real-world studies are required to confirm the safety profile of this increasingly used device,” the researchers said.