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Brain & Heart A left atrial appendage occlusion review

those with a moderate-to-high risk of stroke and high Left Atrial Appendage Closure vs Warfarin for Atrial
risk of bleeding, LAAC therapy is a class IIb indication. Fibrillation) trial protocol. The ASAP trial demonstrated
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In addition, LAAC therapy can be considered for patients that patients with an absolute contraindication to
with atrial fibrillation with end-stage renal disease and an anticoagulation can instead pursue dual antiplatelet
elevated risk of thromboembolic stroke. Comparable safety therapy for 6 months post-procedure as an alternative with
and efficacy of LAAC therapy were observed in a German an ischemic stroke risk lower than that of patients with a
registry-based study by Fink et al. Data on LAAC in this similar CHA2DS2-VASc score. Similarly, the Amulet IDE
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patient population, however, is scarce, and more studies are trial showed dual antiplatelet therapy to be safe and effective
needed to determine the optimal risk reduction strategy in for 6 months after Amulet device placement (Amulet IDE).
these patients. In addition, the PINNACLE-FLX demonstrated efficacy of
In preparing for device implantation, careful pre- direct oral anticoagulant (DOAC) and aspirin for 45 days,
procedural planning must take place to ensure optimal then aspirin and clopidogrel for 6 months (provided that
device deployment and to avoid complications, including the 45-day TEE demonstrated no evidence of PDL >5 mm),
peridevice leak (PDL), device embolization, and thrombus followed by aspirin indefinitely. 18
formation. Imaging of the LAA anatomy is a key part of this.
The overall shape of the LAA tends to fall into four general 4. Evidence supporting the efficacy of LAAO
categories (all shown below): “chicken wing,” “cactus,” Efficacy of LAAO is supported by three randomized
“windsock,” and “cauliflower/broccoli,” the distribution controlled trials and numerous non-randomized studies.
of which is approximately 40%, 30%, 19%, and 3%, One of these studies, the PROTECT-AF, was a multicenter,
respectively. The shape distribution of the LAA ostium is randomized trial conducted with 707 participants across
3
as follows: oval (68.9%), foot-like (10%), triangular (7.7%), 59 centers, following patients prospectively for a mean
water drop-like (7.7%), and round (5.7%). 11 duration of 3.8 years. These patients were randomized to
Evaluating for parameters such as shape, LAA depth, Watchman LAAO device therapy versus medical therapy
and opening orifice diameter (mouth of the LAA) allows with warfarin anticoagulation for a composite endpoint
for optimal selection of device size and type. This is of stroke, systemic embolism, and cardiovascular or
generally accomplished through two-dimensional (2D) unexplained death. The study revealed that events occurred
transesophageal echo (TEE) imaging. 12,13 Although at a rate of 2.3/100 patient-years in the device arm versus
TEE is the standard modality for evaluation of LAA 3.8/100 patient-years in the warfarin arm. This suggested
anatomy as well as the LAA orifice, it has been known that the Watchman device was non-inferior to warfarin. 19
to underestimate the LAA orifice/landing size area. Pre- PREVAIL (Prospective Evaluation of the Watchman
procedural supplemental imaging with coronary computed Left Atrial Appendage Closure Device in Patients with
tomography angiography (CCTA) has been increasingly Atrial Fibrillation Versus Long-Term Warfarin Therapy)
used for appendage sizing and to reduce the risk of high- was another trial studying the difference between device
flow leaks and device malpositioning due to undersizing of therapy for LAAO and traditional medical therapy.
the occlusion device. 14 A total of 407 patients were randomized to either undergo
Not only does pre-procedural imaging help estimate LAAO device therapy with the Watchman device with
the size and type of occlusion device to be used, but it also discontinuation of warfarin afterward, or chronic warfarin
assists in risk assessment. Patients who have an existing therapy. This trial affirmed the non-inferiority of LAAO
LAA thrombus at the time of pre-procedural imaging device therapy to long-term anticoagulation with warfarin,
(either through TEE, CCTA, MRI, etc.) should not undergo as noted in the PROTECT-AF trial. 20
the procedure until anticoagulation is provided for 6 – The PRAGUE-17 (Left Atrial Appendage Closure
8 weeks and the appendage is clear from thrombus at the Versus Direct Oral Anticoagulants in High-Risk Patients
time of repeat imaging. 15 with Atrial Fibrillation) trial was another prospective non-

Consideration must also be taken regarding post- inferiority trial that evaluated LAAO (either the Watchman
procedural anticoagulation regimens. Notably, patients or Amulet device) versus an anticoagulation arm,
undergoing LAAO are often those for whom long-term predominantly with apixaban. This trial also demonstrated
anticoagulation is contraindicated/difficult. However, non-inferiority to DOAC medications, suggesting that
patients who undergo percutaneous closure were previously LAAO device therapy is an effective alternative, regardless
recommended to take warfarin and aspirin for 45 days, of the anticoagulant chosen, in atrial fibrillation patients
then aspirin and clopidogrel for 6 months, then once with high thromboembolic risk. A summary of landmark
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daily aspirin, based on the PROTECT-AF (Percutaneous trials in LAAO is included in Table 2.

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