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Brain & Heart A left atrial appendage occlusion review

for patients. As a result, in recent years, the management includes protection against thromboembolic events in
of atrial fibrillation has faced significant revision, and addition to control of atrial fibrillation itself. To this
3
the focus on stroke-risk stratification and reduction has end, patients must be assessed in terms of their risk for
received increased attention. Historically, protection thromboembolism. This is also balanced by their risk of
from thromboembolic events has been in the form of major bleeding with the use of anticoagulation. The two
anticoagulation, such as factor X inhibitors or Vitamin risk assessments used in atrial fibrillation are the CHA DS -
2
2
K epoxide reductase inhibitors, namely warfarin. These VASC stroke risk assessment and the HAS-BLED bleeding
2
5
medications, however, are not without their inherent risks, score (Table 1). Although anticoagulation is the standard
6,7
particularly major life-threatening bleeding. Up to 90% of therapy for patients at high risk of stroke, LAA closure
of thromboembolic strokes in atrial fibrillation have been (LAAC) therapy is an alternative for patients at high risk of
attributed to thrombi forming in the left atrial appendage thromboembolic events and who have a contraindication
(LAA). To obviate the need for long-term anticoagulation to oral anticoagulation or who may be non-compliant
and reduce bleeding complications, LAA occlusion with oral anticoagulation therapy. The most common
(LAAO) devices offer an alternative mechanical solution indication for LAAC therapy is major bleeding while on
for stroke prevention in patients with atrial fibrillation. 2 anticoagulation. At present, guidelines by professional
Here, we offer a review of existing literature and societies with regard to LAAC devices slightly differ. The
evidence supporting LAAO, device design, techniques of European Society of Cardiology recommendations include
device implantation, and current challenges in reducing consideration of LAAO for prevention of stroke in patients
device-related complications. with atrial fibrillation and contraindications to long-term
oral anticoagulation (class IIb). The most recent ACC/
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2. Anatomy and physiology of the LAA AHA guidelines suggest that LAAC is a class IIa indication
The structure of the LAA is tied closely to its embryological in atrial fibrillation patients with a moderate-to-high
origin. It typically forms in the 4 week of gestation from risk of stroke (CHA DS -VASC score of at least 2), and a
th
2
2
the embryonic left atrium, whereas the proper left atrium contraindication to long-term oral anticoagulation. For
arises from the pulmonary veins. Most commonly, the
3
LAA lies anterosuperiorly over the superior aspect of the Table 1. CHA DS ‑VASC and HAS‑BLED scoring systems
2
2
left ventricle. Lying in the atrioventricular sulcus, it is in CHA DS ‑VASC Point Adjusted annual
close proximity to the left circumflex artery, phrenic nerve, 2 2 stroke rate
and pulmonary veins. In a small percentage of people, the Congestive heart failure 1 0
3
appendage may instead traverse posteriorly in the direction Hypertension 1 1.3
of the pulmonary trunk, along the transverse cardiac
sinus. The interior surface of the LAA is trabeculated in Age>75 years 2 2.2
contrast to the left atrium, which has a smooth interior Diabetes mellitus 1 3.2
surface. This variation in internal structure has been Stroke/TIA/thromboembolism 2 4
3
postulated to contribute in some part to the LAA’s ability Vascular disease (MI, CVA, and PAD) 1 6.7
to harbor thrombi within its cavity, as blood may pool Age 65 – 74 years 1 9.8
in microcavities within the appendage and subsequently Sex category (female) 1 9.6
thrombose. There also exists a significant variability in HAS‑BLED Point Annual bleeding
the dimensions of the LAA, including its length, width, risk
volume, and orifice diameter. Physiologically, the function Hypertension (systolic BP>160 mmHg) 1 1.13
of the LAA is tied to the release of natriuretic hormones, Abnormal renal/liver function (1 point 1 – 2 1.02
and it can be a mediator of fluid and hemodynamic each)
status. Atrial natriuretic and brain natriuretic peptides are Stroke 1 1.88
thought to be released from the LAA in response to atrial Predisposition to bleeding 1 3.74
stretch from fluid distension. 3
Labile INR 1 8.7
3. Risk assessment for atrial fibrillation and Elderly (age>65 years) 1 12.5
pre-procedural evaluation for LAAC Drugs or alcohol use (1 point each) 1 – 2
Atrial fibrillation arises due to arrhythmogenic foci in the Source: Nagasaka et al. 6
Abbreviations: BP: Blood pressure; CVA: Cerebrovascular accident;
atrial walls, which result in disorganized electrical activity INR: International normalized ratio; MI: Myocardial infarction;
in the atria. The standard of therapy for atrial fibrillation PAD: Peripheral arterial disease.
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Volume 3 Issue 3 (2025) 2 doi: 10.36922/bh.4016