Urgent Need to Measure Effects of Direct Oral Anticoagulants

The direct oral anticoagulants (DOACs), which include dabigatran, rivaroxaban, apixaban, and edoxaban, were designed to be given in fixed doses without routine coagulation monitoring. When administered in this manner in trials that included u003e71 000 patients with atrial fibrillation1 and u003e27 000 patients with venous thromboembolism,2 the DOACs were at least as effective as vitamin K antagonists but were associated with less serious bleeding, particularly less intracranial bleeding. Eliminating coagulation monitoring simplifies anticoagulation therapy. This feature, together with their proven efficacy and safety, explains why guidelines give preference to the DOACs over vitamin K antagonists for stroke prevention in atrial fibrillation and for the treatment of venous thromboembolism.Although routine coagulation monitoring is unnecessary, there is an urgent need for readily and rapidly available tests to measure the DOACs. This need will increase with the introduction of costly reversal agents such as idarucizumab for dabigatran3 and andexanet alfa for rivaroxaban, apixaban, and edoxaban.4 Idarucizumab is already licensed, and andexanet is undergoing regulatory review and could be approved later this year. What tests are currently available, and why do we need new ones?Although currently available global tests of coagulation such as the activated partial thromboplastin time (aPTT) and prothrombin time (PT) can be useful to assess the anticoagulant effects of dabigatran and some of the oral factor Xa inhibitors, respectively, the sensitivity of these …