Background Left atrial appendage (LAA) morphology predicts stroke risk in patients with atrial fibrillation. However, it is not precisely understood how LAA morphology influences stroke risk. The present study aimed to investigate the relationship between LAA morphology and local thrombogenesis-related blood parameters in LAA. Methods and Results We enrolled 205 patients undergoing catheter ablation of atrial fibrillation. The prevalence of chicken wing-, cactus-, windsock-, and cauliflower-type LAAs were 23.9%, 32.7%, 29.3%, and 14.1%, respectively. Blood samples were collected from the femoral vein, left atrium, and LAA in each patient. The levels of blood parameters were tested for each blood sample. The cauliflower-type LAA was associated with elevated platelet P-selectin expression, and interleukin-6 levels and with lower NO levels in LAA blood samples (P<0.05) independent of LAA flow velocity and LAA volume. LAA flow velocity, which was lowest in the cauliflower-type LAA, was the only independent predictor of von Willebrand factor antigen and plasminogen activator inhibitor-1 levels in LAA blood samples. In femoral vein blood samples, no significant difference was detected in the above blood parameters among the four LAA morphological types. In all blood samples, the levels of thrombin-antithrombin complex, D-dimer, fibrinogen, and tissue plasminogen activator were comparable among the four LAA morphological types. Conclusions In patients with atrial fibrillation, LAA morphological types might be associated with local platelet activity, fibrinolysis function, endothelial dysfunction, and inflammation.
Keywords: atrial fibrillation; coagulation; endothelial dysfunction; inflammation; left atrial appendage.