Comparison of multiple imaging modalities for measuring orifice diameter and selecting occluder size in patients undergoing left atrial appendage closure

Background: Left atrial appendage (LAA) closure (LAAC) can safely and effectively prevent stroke events caused by atrial fibrillation. However, the structure of the LAA is highly variable among individuals, and the optimal method for obtaining measurements remains unknown.

Hypothesis: We aimed to study the accuracy of left atrial computed tomography angiography (CTA), three-dimensional (3D) reconstruction using CTA, two-dimensional transesophageal echocardiography (2D-TEE), and digital subtraction angiography (DSA) for measuring the diameter of the LAA and compare their value for selecting occluder size.

Methods: We retrospectively evaluated data for 148 patients with nonvalvular atrial fibrillation who underwent successful LAAC. CTA and 2D-TEE of the left atrium and pulmonary vein were performed before LAAC. We performed 3D reconstruction of the left atrium and LAA using Mimics and 3-matics software. DSA of the LAA was performed during surgery.

Results: Values measured via CTA 3D reconstruction were significantly higher than those measured using other methods. DSA-measured values were significantly lower than those measured via CTA and CTA 3D reconstruction. Occluder size was positively correlated with LAA orifice diameter. The differences between occluder size and DSA, 2D-TEE, CTA, CTA 3D reconstruction measurements were 4.96 ± 2.58, 4.64 ± 2.50, 4.04 ± 1.37, and 2.92 ± 1.38 mm, respectively. Intraclass correlation coefficients for these methods were -.067, .006, .241, and .519, respectively.

Conclusion: CTA 3D reconstruction provides the best correlation and consistency between the measured LAA orifice diameter and occluder size. Adding 2-4 mm to the maximum LAA orifice diameter based on 3D-CTA may aid in selecting the appropriate WATCHMAN device.