Assessment of the Dynamism of the Left Atrial Appendage Dimensions: A Computer Tomographic Analysis

Abstract

Background: Device sizing prior to left atrial append-age (LAA) closure is currently primarily based on trans-esophageal echocardiographic as well as invasive angiographic measurements, and can be challenging due to the complex and highly variable anatomy of the LAA. Computerized tomography (CT) is a 3-dimensional imaging modality that is increasingly being used for planning structural heart disease interventions. We assessed the variability of the measurements of the LAA ostium in patients with sinus rhythm and atrial fibrillation referred for CT angiography. Methods: 101 consecutive patients with available retrospective spiral acquisitions as well as multiphase re-constructions between 0 to 90% of the peak R-wave to R-wave were included in this analysis. All acquisitions were performed using a third generation dual source system (Somatom Force, Siemens Healthineers, Forch-heim, Germany). Data sets were transferred to dedicated Software (Ziostation2, Ziosoft Inc., Tokyo, Japan) which allows dynamic evaluation of the LAA ostium through the different phases of the cardiac cycle. Mul-tiplanar reconstructions were aligned with the plane of the LAA ostium and measurements where performed in a cross-sectional plane orthogonal to the long axis of the LAA at the level of the left circumflex coronary artery. Four measurements were performed: area, circumference, area-derived diameter (√[area/∏] x 2) and circum-ference-derived (perimeter/∏). Furthermore assessment of the length if the LAA was assessed in all patients.