Combination of a new oral anticoagulant, aspirin and clopidogrel after acute coronary syndrome: new therapeutic standard?

Effective secondary prevention after acute coronary syndrome (ACS) is largely dependent on dual antiplatelet therapy (DAPT). Despite DAPT, however, patients remain at substantial risk of major adverse cardiovascular events (i.e., cardiovascular death, myocardial infarction, stroke), and, therefore, combination therapy of oral anticoagulant and antiplatelets has been previously proposed. Because of the increase in bleeding and the cumbersome management of vitamin K antagonists, such combination therapy has never gained much popularity. The recent development of new, non vitamin K antagonists, direct oral anticoagulants (NOACs), including dabigatran, apixaban, rivaroxaban, and darexaban, which have more favorable pharmacokinetics and pharmacodynamics, as well as higher safety, has renewed the interest on combination therapy. Whereas phase II trials with dabigatran, apixaban, rivaroxaban, and darexaban have consistently shown an increased bleeding risk with combination therapy, a potential increased efficacy has emerged for apixaban and rivaroxaban, thereby prompting phase III studies. Both APPRAISE-2 and ATLAS ACS 2-TIMI 51 trials confirm a dose-dependent increase in major bleeding events, including intracranial, with apixaban and rivaroxaban when combined with DAPT. Low-dose (2.5 mg twice daily) rivaroxaban on the other hand, is associated with a significantly higher efficacy on the occurrence of combined cardiovascular death, myocardial infarction, stroke, and of stent thrombosis. Owing to the persistent uncertainty regarding the net clinical benefit of combined therapy of NOAC, namely low-dose (2.5 mg twice daily) rivaroxaban and DAPT of aspirin and clopidogrel, further studies are warranted to identify the ACS patient who will benefit most from such treatment, also in comparison to the current therapeutic standard represented by DAPT of aspirin and ticagrelor (or prasugrel).