Fig. 7.1
The Amplatzer Amulet device consists of a distal lobe and a proximal disc, which are connected by an articulated waist. The lobe has 6–10 pairs of stabilizing wires to securely anchor the device in the LAA
Fig. 7.2
There are eight different sizes of Amplatzer Amulet devices, which can be divided to two groups: devices 16–22 mm that have a shorter (7.5 mm) lobe length and devices 25–34 mm that have a longer (10mm) lobe length. The smaller devices usually require more oversizing. When using large Amulet devices, especially in LAAs with a small ostium and a large neck, the distance from the mitral valve should be evaluated before and after device implantation to avoid any potential impingement
7.2 Step by Step
7.2.1 Before Puncture
Usually, the patient is under general anesthesia or conscious sedation due to the discomfort from the use of intraprocedural TEE. Intracardiac echocardiography (ICE) may be also used with excellent success.
At the beginning, TEE is performed to exclude thrombus, which is usually a contraindication to perform LAAO.
The baseline status of the pericardial space, the mitral valve and the left superior pulmonary vein (LSPV) are briefly assessed.
The LAA is scanned from 0° to 135° and the maximum and minimum diameters of the ostium and the landing zone are recorded (Fig. 7.3a–c). Real time 3D TEE may allow for better spatial visualization of the LAA and more comprehensive evaluation of the device during the procedure (Fig. 7.3d).
The use of multislice computed tomography (MSCT) prior to the procedure will also facilitate procedural planning as it has higher spatial resolution and is less operator-dependent than TEE.
Fig. 7.3
Echocardiographic scanning from 0 to 135 degrees is recommended before Amplatzer Amulet implantation to evaluate the dimensions of the LAA ostium and neck. The LAA neck definition (blue line) is different than the one used for the Watchman device and is measured 12 mm distal to the LAA ostium (red line). Also the LAA depth definition is different: for Amulet a line perpendicular to the LAA ostium (green line) is used, whereas for Watchman a line from the ostium to the tip of a distal lobe is used (orange line)
7.2.2 Vascular Access: Transseptal Puncture
The right femoral vein is punctured using standard technique.
Transseptal puncture (TSP) is performed under fluoroscopic and TEE guidance in the infero-posterior portion of the fossa ovalis.
Unfractionated heparin is given in a dose of 100 IU/kg to obtain an activated clotting time (ACT) of 250–300 s. Giving a half dose of heparin before TSP provides some antithrombotic protection in case of a difficult or prolonged TSP.
7.2.3 Device Sizing
A selective injection of contrast in a right anterior oblique (RAO) 30°/cranial 20° view and in a RAO 30°/caudal 20° view is performed through the transseptal sheath with a 5–6 French (F) marker pigtail catheter sitting inside the LAA (Fig. 7.4).
Device sizing is based on multimodality imaging (TEE, angiography and/or MSCT).
Amulet needs to be oversized in relation to the maximum dimensions of the landing zone (Fig. 7.2) but the device should be less oversized in oval LAA anatomies.
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