Increased epicardial adipose tissue, growth differentiation factor-15 and atrial size are associated with left atrial stasis in atrial fibrillation: a cardiac computed tomography study

Background/Introduction Atrial fibrillation (AF) is a common arrhythmia, underpinned by atrial cardiomyopathy. The thorough pathophysiology that underlies these processes is not completely understood. Left atrial (LA) wall-related modifiers, as epicardial adipose tissue (EAT), inflammation, and wall fibrosis, are well-described active players and relate to LA enlargement. Growth differentiation factor-15 (GDF-15) is one of the inflammation biomarkers associated with the risk of mortality in AF. Increased LA blood stasis has been shown in AF patients using time-resolved cardiac computed tomography (trCT) and has been associated with the ratio of maximum LA volume and left ventricular stroke volume, the so-called retention ratio. Further, the hypercoagulable status of AF patients seems to relate to EAT and inflammation, in addition to abnormal LA blood flow. Elevated Von Willebrand factor (VWF) levels correlate with LA blood stasis severity. The above-named factors seem to be associated to atrial cardiomyopathy, but their interaction during disease progression is still to be clarified. Purpose To explore the relationship between LA enlargement, LA EAT, inflammation (GDF-15), coagulation (VWF) and LA stasis (retention ratio) in an AF cohort. Methods Forty-five AF patients were recruited before their first AF ablation (between 2019-2023). All participants were in sinus rhythm (SR) and on oral anticoagulants at inclusion. The participants underwent trCT, and the images were segmented to quantify the LA EAT volume and the LA retention ratio. Blood samples were collected before intervention. Analysis of data distribution, correlation, and linear regression were performed. Results The participants were predominantly men, aged 64±8 years. The baseline characteristics and results summary can be seen in Figure 1. A segmentation example is shown in Figure 2. The data distribution was predominantly non-parametric. There were significant correlations between indexed LA minimum (min) volume and retention ratio (P < 0.001, rho=0.811, 95%CI [0.675, 0.894]), between GDF-15 and indexed LA EAT volume (P = 0.006, rho=0.404, 95%CI [0.116, 0.629]), and between GDF-15 and retention ratio (P = 0.038, rho=0.310, 95%CI [0.009, 0.559]). VWF did not correlate significantly to any of the parameters (P > 0.276). The linear regression analysis shows that both indexed LA min volume and LA EAT volume can predict the retention ratio (R² = 0.63, F (1,43) = 72.99, P < 0.001, R² = 0.11, F (1,43) = 5.38, P = 0.025, respectively). The relationship between GDF-15 and retention ratio was not linear. Conclusion(s) Markers of LA wall modification by way of LA EAT, GDF-15 and LA min volume are associated with LA stasis expressed as retention ratio in AF patients in SR. VWF does not correlate to stasis in this early AF stage.