Quantification of the Anticoagulatory Effect of Novel Anticoagulants and Management of Emergencies

Novel oral anticoagulants such as dabigatran which specifically target thrombin, and rivaroxaban and apixaban which are activated factor X inhibitors are in the process of being approved for use in Switzerland to lower the risk of stroke in patients with atrial fibrillation. Although there is currently no evidence relevant to the clinical benefit for monitoring anticoagulant intensity of these drugs in routine clinical practice, the need for measuring the anticoagulant effect of the novel anticoagulants may arise in some clinical situations such as: haemorrhage and thrombosis occurring under anticoagulation, an emergency surgery, drug interaction, overdose, impaired renal or liver function compliance monitoring. Furthermore, the effect of novel anticoagulants on routine coagulation tests must be known by the clinician. To date, clinical experience is insufficient to definitively guide the management of emergencies including major bleeding in patients receiving these drugs. Indeed, there is currently no specific antidote available. Fortunately, the half-life of these agents is short, hence treatment interruption is most of the time sufficient to reverse the anticoagulant and clinical effect. In case of life-threatening bleeding, dabigatran can be removed by haemodialysis, and rivaroxaban and apixaban can be antagonised by nonactivated prothrombin complex concentrates. More importantly, preventive attitudes should be placed upfront, before the administration of the novel oral anticoagulant. The prescriber has the responsibility to carefully review possible drug interactions as well as to check renal and liver functions and to provide the patient with an identification card containing personal information, the name of the anticoagulant and treatment indication. In addition, blood cell counts, prothrombin and activated partial thromboplastin times measurements need to be performed before the introduction of the anticoagulation, at least in elderly patients.