US responds to ESC's "triple-therapy" advice for AF patients with stents

Boston, MA - A group of North American antithrombotic-therapy experts have responded to the European Society of Cardiology's recommendations on anticoagulant and antiplatelet therapies in atrial-fibrillation patients undergoing stenting with a consensus document of their own, published online July 25, 2011 in Thrombosis and Haemostasis^[1].

Dr Gregory YH Lip (University of Birmingham, UK), the lead author of the recent European consensus on antithrombotic therapy in PCI patients with AF^[2], asked Dr David Faxon (Brigham and Women's Hospital, Boston, MA) and colleagues to "put together a North American view, since there are differences in practice between Europe and the United States on this issue, and this remains a controversial area without strong data to help support or guide clinicians on how to manage patients on triple therapy: aspirin, clopidogrel, and warfarin," Faxon told heartwire . The new consensus document is intended to provide a "balanced view of what the North American [experts] feel about this issue and provide some guidelines for clinicians on how they might treat patients who are confronted with this problem, which is not uncommon."

About 5% of PCI patients have atrial fibrillation or other indications for chronic oral anticoagulant therapy, but triple therapy increases the risk of major bleeding, Faxon et al explain. The American College of Cardiology/American Heart Association/European Society of Cardiology (ACC/AHA/ESC) guidelines have classified triple therapy in PCI patients with atrial fibrillation as a class IIb recommendation (may be considered) with a level of evidence C (expert opinion). "Ultimately, the clinician has to balance four things—risk of bleeding vs the risk of stroke in the nonanticoagulated AF patient vs the risk of recurrent cardiac ischemia in the ACS patient vs the risk of stent thrombosis," Lip told heart wire . The decision process depends on the patient's risk of stroke, bleeding, type of stent implanted, and whether the patient has acute coronary syndrome or is stable, he explained.

"I'm not sure there's as much difference [between the North American and European consensus] as we initially thought," Faxon said. "The North American [consensus] is more concerned with major bleeding on triple therapy than the European guidelines are. We've been more conservative on the duration of triple therapy and the use of drug-eluting stents, but it's not a dramatic difference.

"I think it's a timing issue. Their paper appeared in [2010], and since that time, a lot of newer studies of antiplatelet agents have come out that have shown considerable concern about high bleeding risks," Faxon said. "We're becoming more and more conscious of the downside of these antithrombotic agents.

"We've limited the duration of triple therapy to certain groups for whom there is a low risk of bleeding and a high potential for gain," Faxon said. For example, the North American consensus does not recommend drug-eluting stents for anyone with a high bleeding risk because of the greater risk of thrombosis with drug-eluting stents in patients not on triple therapy. "The Europeans are not as strong on that," Faxon said. The European consensus recommends avoiding or "strictly limiting" drug-eluting stents to patients in whom a "significant benefit is expected as compared with bare-metal stents" such as those with long lesions, small vessels, or diabetes.

Lip told heart wire it is "probably more important to emphasize the many similarities between the recommendations in the two important documents.

"This is an evolving field, and the consensus document by Faxon et al provides an important guide to clinicians on when and how long to administer triple antithrombotic therapy to a patient with atrial fibrillation who has undergone a coronary-stent placement," he said. "The European document also provides coverage of what to do in the acute stage of management for anticoagulated patients with AF who present with an acute coronary syndrome, including those who require primary percutaneous coronary intervention for ST-elevation myocardial infarction."

Because there are little rigorous clinical trial data on triple therapy in patients with AF, the ACC and AHA are unlikely to issue formal guidance on it, according to Faxon. "They avoid the topic because we have only mostly observational studies to help guide the treatment," he said. "We don't really have a good trial to help manage these patients." Future trials should address the duration of triple therapy with the next generation of drug-eluting stents, he said. The current FDA and professional guidelines advise 12 months, "but the newer third generation and hopefully the fourth generation of drug-eluting stents may require much shorter periods of time, and if they do, it will greatly relieve this problem," he said.

Heartwire from Medscape © 2011 

Cite this: US responds to ESC's "triple-therapy" advice for AF patients with stents - Medscape - Jul 28, 2011.