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.