Elevated thrombin generation levels in the left atrial appendage in patients with atrial fibrillation. (3rd October 2022) - Elias, A
Abstract: Introduction: Atrial Fibrillation (AF) is the most common sustained arrhythmia. Thrombus formation in the left atrial appendage (LAA) increases the risk for stroke and systemic embolism in AF patients. The proposed mechanisms for thrombus formation in the LAA are stasis, endothelial dysfunction and local hypercoagulability. The aim of this study was to compare thrombin generation potential in various heart chambers among AF patients. Material and methods: A prospective cross-sectional study of 47 patients with AF undergoing pulmonary vein isolation (PVI). Blood samples from the femoral vein (FV), right atrium (RA), left atrium (LA) and LAA were collected during the PVI procedures. The Samples were collected before heparin administration. Thrombin generation was assessed by the calibrated automated thrombogram (CAT). Results: A total of 47 patients (36.2% female, mean age 58.7±13, 59.6% with CHADS-VASc ≥2) were enrolled into the study. The mean endogenous thrombin potentials (ETP) were 1580±558, 1433±540, 1141±611 and 1487±760 in the FV, RA, LA and LAA, respectively (P<0.05). The mean thrombin peak heights were 244±124, 199±102, 139±94 and 195±129 in the FV, RA, LA and LAA, respectively (P<0.05). A post-hoc pairwise comparison demonstrated elevated thrombin generation in the LAA compared to the LA (P=0.014). Furthermore, LA thrombin generation levels were significantly lower from the FV and RA (P<0.05). Conclusion: In patients with AF, the LAA has increased thrombotic potential compared to the LA. These findings might explain why the LAA is more predisposed to thrombus formation than the LA. Funding Acknowledgement: Type of funding sources: None.