Atrial fibrillation and dementia: Relationship, physiopathological mechanisms, and anticoagulant treatment

Atrial fibrillation (AF) and dementia are highly prevalent pathologies. In the past two decades, multiple observational studies have been published that demonstrate the causal relationship between AF and dementia. These pathologies share common vascular risk factors such as those included in CHA2DS2-VASC score. Several physiopathological mechanisms have been involved, among the theories proposed to date are: clinical stroke and silent brain infarction, cerebral hypoperfusion and vascular inflammation. Although dementia is not a contraindication for oral anticoagulation, this population is still undertreated due to fear of hemorrhagic events. More and more studies propose that the benefit of anticoagulation in patients with dementia and AF outweighs the hemorrhagic risk, due to the reduction of morbidity and mortality with a net clinical benefit. Concerning the association between effective anticoagulation therapy and the risk of developing dementia, there are data that suggest a possible beneficial effect, however, we need larger scale studies to evaluate the real influence of anticoagulant treatment in prevention of dementia. Some studies showed a borderline significant association between the use of direct oral anticoagulants and the tendency to decrease cognitive impairment when compared with warfarin therapy. There are three ongoing clinical trials to clarify whether the type and use of anticoagulants are related to the development of cognitive decline.