NOAC and Vitamin-K Antagonists for ACS, PCI in Atrial Fib: European Consensus Statement

August 27, 2014

SOPHIA ANTIPOLIS, FRANCE — European societies published a "joint consensus statement" on antithrombotic therapy in patients with nonvalvular atrial fibrillation (AF) who present with an acute coronary syndrome (ACS) and may undergo PCI, one that updates the field since the advent of new oral anticoagulant (NOAC) agents and "new-generation" drug-eluting stents (DES)[1]. It also addresses antithrombotic therapy in AF patients undergoing another recent innovation, transcatheter aortic-valve implantation (TAVI).

The document was published August 25, 2014 in the European Heart Journal, the flagship journal of the European Society of Cardiology (ESC), which on the document's publication announced that it presents "the first comprehensive recommendations on the use of NOACs in this setting."

Addressing one oft-cited dilemma, the statement recommends that patients already with ACS "who develop new-onset AF while on dual antiplatelet therapy" should also be given a vitamin-K antagonist or a NOAC.

"The potential role of NOACs for patients with ACS and AF has not been directly assessed, since AF patients requiring oral anticoagulants were systematically excluded from recent ACS trials, and conversely, patients with recent ACS were likely to have been excluded from phase 3 stroke-prevention trials in AF patients," the formal document report states.

Still, "There is no strong evidence to suggest that NOACs behave differently from vitamin-K antagonists in the setting of ACS or stenting."

There is a limited evidence base for vitamin-K antagonists, however. The WOEST trial, the first randomized trial of dual- vs triple-antithrombotic therapy in PCI—unveiled at the ESC 2012 Congress and covered then by heartwire —showed superior results with a vitamin-K antagonist plus clopidogrel compared with that pairing plus aspirin. There were fewer total bleeding complications (p<0.001), although no significant differences in major bleeding; there was no increased risk of stent thrombosis or ischemic events. A secondary composite clinical end point that included death, MI, and stroke, among other events, was reduced with dual-agent treatment at one year (p=0.025).

"There are some important issues that may limit the conclusions of the WOEST trial [in the setting of AF with ACS]: only 69% of patients received oral anticoagulation due to AF. Most of the patients underwent elective PCI (70%–75%), and the femoral approach was used in 74%, increasing access-site bleeding," the statement notes.

"Although it might be premature to abandon aspirin after stent implantation in AF patients requiring oral anticoagulation based solely on the results of WOEST, dual therapy with oral anticoagulants and clopidogrel may be considered as an alternative to triple therapy in selected AF patients at low risk of stent thrombosis/recurrent cardiac events."

Throughout, the document states that new-generation DES may be preferred to bare-metal stents in patients with a low risk of bleeding based on HAS-BLED score, as they appear to be less thrombogenic. "New data on dual-antiplatelet-therapy cessation . . . shows no difference between bare-metal stents and DES, especially with new-generation stents." Prior-generation DES are described as a distant third choice in this setting.

The document points to two "ongoing or planned" trials exploring NOACs in patients with AF undergoing PCI. The PIONEER AF-PCI compares rivaroxaban (Xarelto, Bayer/Johnson & Johnson) at two separate dosage levels vs a vitamin-K antagonist, along with single-agent antiplatelet therapy or "various combinations of dual-antiplatelet therapy." The trial has dual primary end points of clinically significant bleeding at one year and a composite of "major bleeding, minor bleeding, and bleeding requiring medical attention."

On the other hand, the report states, "PIONEER AF-PCI is not powered to detect differences in stroke rates." The trial has a projected enrollment of 2169 and is scheduled for completion in 2016.

The document also refers to the recently announced RE-DUAL PCI trial, which is comparing dabigatran (Pradaxa, Boehringer Ingelheim) at two dosage levels, plus a single nonaspirin oral antiplatelet, vs warfarin plus dual-agent antiplatelet therapy in patients with AF undergoing PCI. The trial is following patients for a composite clinical end point that includes death, MI, and stroke.

According to the ESC announcement, the consensus document "was written jointly by the ESC Working Group on Thrombosis, the European Heart Rhythm Association (EHRA), the European Association of Percutaneous Cardiovascular Interventions (EAPCI), and the Acute Cardiovascular Care Association (ACCA), all of the ESC. It was also endorsed by two international societies, the Heart Rhythm Society and the Asia Pacific Heart Rhythm Society."

No disclosures were provided in the journal report or its online supplement.

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