Page 54 - BH-3-3

Brain & Heart A left atrial appendage occlusion review

a percutaneous solution to LAAC. Introduced in 2001, 7.2.4. LAmbre (Lifetech Scientific Co, Ltd, Shenzhen,
44
this self-expanding device was constructed with a nitinol China)
frame with struts creating a cage, which was covered with a The LAmbre device is another nitinol-based device that
membrane coated with expanded polytetrafluoroethylene contains a self-expanding umbrella cover on the distal end
(ePTFE). The purpose of the ePTFE coating was to provide covered by a polyethylene terephthalate membrane. This
an occlusive surface at the orifice of the LAA as well as umbrella segment has eight structural support struts, each
to promote healing post-implantation. The device also
44
contained anchors that served to adhere to the internal with a hook that is engaged at the time of deployment and
wall of the LAA and limit the movement of the device adhesion of the umbrella membrane with the LAA wall.
itself. The delivery system of the device also allowed for The umbrella is also connected to a proximal covered disk
post-deployment collapse of the device, contrast injection, through an articulating waist. Based on the number of lobes
as well as complete removal of the device, in the event that and size of the LAA, one of two models can be utilized,
a different size device was necessary to accommodate the and both are recapturable and are able to be repositioned
46,50
specific anatomy of the LAA. Although revolutionary, the if necessary.
device is no longer commercially available in the United 7.2.5. LARIAT (SentreHeart, Redwood City, CA)
States. 44,45
The LARIAT device is a suture delivery system that serves
7.2.2. Watchman/Watchman FLX (Boston Scientific, to deliver sutures to ligate soft tissues. Although approved
Natick, MA) by the FDA for this purpose, it is currently off-label for
The Watchman device is a self-expanding device that use in LAA ligation. The device utilizes magnet-tipped
consists of a 10-strut design assimilating a nitinol frame. guidewires as well as a compliant balloon parked distal
The side of the cage facing the LAA orifice is also covered to the LAA orifice. The procedure relies on dual access,
with a polyethylene terephthalate membrane that serves as with the balloon being delivered percutaneously with
a barrier to thrombus exit from the LAA as well as promotes endocardial and transseptal access, whereas the snare
endothelialization. The distal end is open and harbors suture is delivered through an epicardial access approach.
anchors that aid in immobilizing the device within the One magnetic tip is extended from the balloon catheter to
LAA. Various sizes are available to accommodate varying the tip of the LAA, after which the balloon is expanded.
LAA anatomies, and the device is fully recapturable and The second magnetic tip is introduced from an epicardial
exchangeable for different-size devices. 25,46 approach to approximate the first tip. With the balloon
expanded, a snare is introduced from an epicardial
The Watchman FLX was subsequently introduced approach around the LAA and is tied down over the LAA
following the Watchman device and offers a closed cage orifice. The balloon is then deflated, and the suture is cut
design (closed distal end), which is in contrast to the loose. The magnetic tips are then retracted, and the access
first-generation Watchman device. Compared to the first- sites are closed in usual fashion. 23,51
generation Watchman, the FLX design offers a greater
surface area of polyethylene terephthalate membrane to 7.2.6. CLAAS device (Conformal Medical, Nashua, NH)
promote endothelialization and minimize PDL, a greater
number of struts leading to increased radial strength, as The CLAAS device is a self-expanding occluder consisting
well as more anchor points. 47 of a cylindrical nitinol endoskeleton covered with a
conformable, porous foam. The endoskeleton is stabilized
7.2.3. Amplatzer Amulet (Abbott Vascular, Santa by two anchoring wires arranged in two parallel rows. The
Clara, CA) device is available in only two sizes. Clinical feasibility has
The Amulet device by Abbott Vascular is a revision of the been demonstrated in one first-in-human study. 52
Amplatzer Cardiac Plug (ACP) device, which utilized a 8. Techniques for device implantation
nitinol mesh and polyester fabric disc. The newer Amulet
device contains more wires for stabilization in the proximal Delivery of percutaneous LAAC devices is a multi-step
and distal lobes, and suggests more stability within the LAA process. Typically, the procedure is performed under
due to the increased length of the distal waist. The distal general anesthesia, and the entire procedure proceeds under
waist is longer, and the proximal disk has a larger diameter fluoroscopic and echocardiographic guidance, commonly
53
than the previous ACP device. The Amulet device also has with a transesophageal echocardiogram. Vascular access
a decreased need for oversizing during implantation, and is achieved through the femoral vein, and catheters are
this is thought to lead to fewer device-related thrombosis extended up to the right atrium. The transseptal technique
events. 23,48,49 is employed in order to gain access to the left atrium.

Volume 3 Issue 3 (2025) 6 doi: 10.36922/bh.4016