Introduction
Near 15% of ischemic stroke is caused by atrial fibrillation (AF). AF is associated with a prothrombotic state which increases the risk of stroke fivefold compared to the general population. It is well known, that increase thromboembolism risk in AF is associated with a combination of pathophysiological mechanism, a Virchow’s triad1: (1) blood stasis; (2) abnormalities of the vessel wall; and (3) regional and systemic inflammation resulting in a prothrombotic and hypercoagulable state2. Over 90% of all intracardiac thrombus formation in patients with AF are observed in the left atrial appendage (LAA).
Elimination of the LAA from the circulatory system became an alternative method for stroke prevention in patients with AF. The ESC and ACC/AHA guidelines give the surgical LAA occlusion or exclusion (LAAO) concomitant to cardiac surgery or thoracoscopic AF surgery a Class 2B recommendation3,4. Interventional, percutaneous LAA ligation or occlusion procedure had a Class 2B recommendation only for AF patients contraindicated for oral anticoagulation (OAC)3,4.
Multiple observational studies indicate the feasibility and safety of surgical or percutaneous LAA occlusion/exclusion procedure3-6. However, the assessment of the effectiveness of these procedures is always based on clinical observation with stroke or other thromboembolic incidences as an endpoint. Importantly, those observations are not supported by the results of the basic science or translational research study based on biomarkers approach in thromboembolic risk assessment after LAA elimination 3-6. Also, a large randomized trial such as LAAOS III, that is currently underway, asses only the clinical outcomes of LAA elimination7. Therefore, there is a great need to support existing observational studies of LAA elimination through the implementation of basic research on the coagulation system and effect on the prothrombotic status.
The aim of the current study was to investigate if epicardial LAA elimination from the cardiovascular system has an effect on the coagulation system and prothrombotic status in AF patients. We also analyzed the relationship between the level of hypercoagulability, fibrinolytic markers and clot lysis time depending on the presence of LAA.