[Novel oral anticoagulants and atrial fibrillation in the elderly]

Abstract

Atrial fibrillation treatment relies on anticoagulation therapy that reduces the risk of stroke. Vitamin K antagonists (VKA) were the only oral anticoagulant drugs for more than 50 years, but they are difficult to manage especially in the elderly. In France, VKA are the main cause of iatrogenic hospitalizations with about 17,000 hospitalizations per year and around 4,000 to 5,000 deaths per year. Pharmacologic properties of VKA, especially the narrow therapeutic margin explain the complexity of their management. Several studies have shown that patients treated with VKA were on average only 50% of the time with an INR in the therapeutic range. In other words, patients are, half of the time, either-under treated or over-treated. Within this framework, development of new oral anticoagulant drugs appeared necessary, in order to obtain drugs with larger therapeutic margin and a better risk/benefit profile than VKA. Three large randomized clinical trials including almost 50,000 patients with 20,000 subjects over 75 years old and 8,000 over 80 years old, show a better risk/benefit profile of the new oral anticoagulants (NOAC) than VKA, characterized by a 50% reduction of cerebral hemorrhages, 22% reduction of stroke and 12% reduction of total mortality. Meanwhile, their renal elimination and the lack of control of the biological efficacy need to be taken into account for their prescription. Renal failure (estimated glomerular filtration rate according to Cockcroft formula < 30 mL/min) contraindicates their use. Their half-life is shorter than that of VKA and the biological monitoring is not available, thus a good adherence to the treatment is important. Studies specifically conducted among geriatric older population with poly-pathologies and frail are therefore needed to evaluate tolerance of NOAC in real life conditions.

Keywords: atrial fibrillation; elderly; novel oral anticoagulants.