New oral anticoagulants for atrial fibrillation: are they worth the risk?

Atrial fibrillation (AF) is the most common cardiac arrhythmia in the U.S. Anticoagulation is recommended for stroke prevention in AF patients with intermediate-to-high stroke risk (i.e., patients with a CHADS2 score of 1 or greater). Warfarin was previously the only option for oral anticoagulation in these patients, but three new oral anticoagulants have become available as alternatives for warfarin in patients with nonvalvular AF. The advantages of the newer agents include a rapid onset, predictable pharmacokinetics, and no need for routine anticoagulation monitoring. Dabigatran (Pradaxa) and apixaban (Eliquis) have demonstrated improved efficacy compared with warfarin. Rivaroxaban (Xarelto) was non-inferior to warfarin for stroke prevention in AF. Apixaban demonstrated a reduced incidence of major bleeding compared with warfarin and a reduction in all-cause mortality. Limitations to the use of the new oral anticoagulants include the lack of a reversal agent; an inability to use the therapies in specific patient populations (such as those with severe renal or hepatic impairment); limited experience with drug-drug and drug-disease interactions; and a lack of available coagulation tests to quantify their effects. Although the newer agents have higher acquisition costs, the benefits of cost savings may be derived from the potential for decreasing the incidence of hemorrhagic stroke and intracranial bleeding and reducing the need for anticoagulation monitoring. Benefits and risks should be carefully weighed before these agents are prescribed for patients presenting with new-onset AF.