Anatomical variability in left atrial appendage wall thickness and its impact on occlusion device implantation technique

Background The left atrial appendage (LAA) has gained significant importance in recent years due to its role in preventing cardioembolic events through percutaneous closure. Anatomically, the LAA comprises a neck and lobes with variable morphology, whose thickness and stiffness may influence the implantation technique and the occurrence of periprosthetic leaks. Aims To evaluate the variability and distribution patterns of LAA neck thickness using cardiac computed tomography (CCT) analyzed with ADAS 3D software. Additionally, to assess whether thickness affects device stability as a predictor of periprosthetic leaks through follow-up with transesophageal echocardiography (TEE) and CCT Methods CCT images were acquired to determine the maximum volume of the left atrium before device implantation. Using ADAS 3D software, the LAA was segmented into two structures: the neck and the lobes. Neck thickness was analyzed using a novel tool designed for myocardial wall thickness measurement, which is also applicable to the LAA. Thickness was represented using a color-coded system: red (<1 mm), yellow (1–2 mm), green (2–3 mm), blue (3–4 mm), and violet (>4 mm) (Figure 1). Follow-up was conducted through an in-person consultation at an average of four months, including TEE and prior CCT evaluation to assess procedural complications and periprosthetic leaks (Figure 1). Results A total of 25 patients were included: 20 with atrial fibrillation and contraindications to anticoagulation who underwent left atrial appendage occlusion (LAAO), and 5 controls without structural heart disease. Patients undergoing LAAO were older and had more comorbidities, with a CHADS-VASc score of 4 ± 1.3 and a HAS-BLED score of 3 ± 1.5. The analysis included an average of 734 ± 167 data points per patient. The mean LAA neck wall thickness was lower in the LAAO group compared to controls (1.18 ± 0.49 mm vs. 1.29 ± 0.61 mm, p < 0.001). At four months, 30% of patients presented leaks, which were significantly associated with reduced wall thickness (1.17 ± 0.5 mm vs. 1.23 ± 0.57 mm, p < 0.01). No major ischemic or hemorrhagic events were recorded, with a single case of BARC 3A Conclusions Measuring LAA thickness using CCT is feasible and may impact device stability and the occurrence of periprosthetic leaks. Patients who underwent percutaneous closure had a thinner LAA neck compared to the control group. Thickness quantification allowed for the analysis of its relationship with leak occurrence, without significant ischemic or hemorrhagic events. Pre-procedural assessment of LAA thickness could help optimize device selection and improve clinical outcomes.