Abstract 3314: Visualization of the Left Atrial Appendage in 3-Dimensions: Complex Anatomy and Structure in Multidetector CTA as an aid to Percutaneous Obliteration Strategies

Abstract

Backgrounds: The left atrial appendage (LAA) is a structure with unique anatomic and functional features. Unfortunately it is the source of ≥ 90% of all cardiac emboli. Recently, percutaneous LAA obliteration was developed to limit cardioembolic events in patients with atrial fibrillation. The feasibility of this treatment is under study to eliminate anticoagulation and simultaneously eliminate cardioembolic events. We examined the LAA from the standpoint of its structure, function compared with the RAA, as well as analyzing its complexity with Multidetector CT (MDCT). Methods and Results: 64-slice MDCT was used to visualize the LAA and RAA in 25 patients. All patients were scanned and a 3D volume rendered technique. Visual comparison between LAA and RAA was performed and LAA orifice diameter, circumference, total and usable length were measured in 2D and 3D. MDCT images revealed complicated LAA structure including small septation, features often not completely appreciated by 2D images (Figure ). 3D images demonstrated 32% single and 28% multiple septae in LAA. There was an excellent correlation of minimum orifice diameter (95%CI 0.46 – 0.94, p<.0001), circumference (CI 0.25– 0.77, p=.0005), and total depth (CI 0.22–1.21, p=.0064) between 2 groups. No relationship was found between maximum diameter and usable LAA length in the 2 groups. Conclusions: LAA imaging in 3D by MDCT is an excellent method to visualize complex anatomy and morphology. The usable LAA length for device implant bears no relation to 2D and 3D analysis, an important consideration for obliteration technologies.