Atrial fibrillation (AF) is characterised by an increased risk of pathological thrombus formation due to a disruption of physiological haemostatic mechanisms that are better understood by reference to Virchow’s triad of ‘abnormal blood constituents’, ‘vessel wall abnormalities’ and ‘abnormal blood flow’. First, there is increased activation of the coagulation cascade, platelet reactivity and impaired fibrinolysis as a result of AF per se, and these processes are amplified with pre-existing comorbidities. Several prothrombotic biomarkers including platelet factor 4, von Willebrand factor, fibrinogen, β-thromboglobulin and D-dimer have been implicated in this process. Second, structural changes such as atrial fibrosis and endothelial dysfunction are linked to the development of AF which promote further atrial remodelling, thereby providing a suitable platform for clot formation and subsequent embolisation. Third, these factors are compounded by the presence of reduced blood flow secondary to dilatation of cardiac chambers and loss of atrial systole which have been confirmed using various imaging techniques. Overall, an improved understanding of the various factors involved in thrombus formation will allow better clinical risk stratification and targeted therapies in AF.
- atrial fibrillation
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Contributors WYD performed the literature search and drafted the manuscript. DG and GL provided critical revisions. All authors approve the final version of the manuscript for publication.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests DG: speaker for Bayer, BMS/Pfizer, Boehringer Ingelheim, Daiichi-Sankyo, Medtronic, Biosense Webster and Boston Scientific. Proctor for Abbott. Research Grants from Medtronic, Biosense Webster and Boston Scientific. GL: consultant for Bayer/Janssen, BMS/Pfizer, Medtronic, Boehringer Ingelheim, Novartis, Verseon and Daiichi-Sankyo. Speaker for Bayer, BMS/Pfizer, Medtronic, Boehringer Ingelheim and Daiichi-Sankyo.
Patient and public involvement Patients and/or the public were not involved in the design, conduct, reporting or dissemination plans of this research.
Patient consent for publication Not required.
Provenance and peer review Not commissioned; externally peer reviewed.
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