January 4, 2011 (Dallas, Texas and Washington, DC) — Three US-based societies have jointly released an update to the existing guidelines for the management of atrial fibrillation (AF), one that accounts for some, but not all, of the recent big developments in the field.
Included are new recommendations for how to handle rate-control therapy, a recently introduced antiarrhythmic agent, a catheter-based treatment that's already widely performed, and an antithrombotic strategy that may have less of a role to play in the future.
The document from the American College of Cardiology (ACC), American Heart Association (AHA), and Heart Rhythm Society (HRS), which updates guidelines published in 2006 [ 2 ], was released December 20, 2010 on the organizations' respective websites and will be published in their flagship journals. It follows publication of new AF guidelines from the Canadian Cardiovascular Society (CCS) in September and the European Society of Cardiology (ESC) in October, as reported by heartwire.
The Dabigatran Factor
The wheels were turning on all three guidelines documents long before the market availability of dabigatran (Pradaxa/Pradax, Boehringer Ingelheim); the drug's recent approvals for AF in the US and Canada were seminal events in AF management, with potential for greatly simplifying anticoagulation for embolic stroke prevention for many patients and possibly making it safer.
The US and Canadian guidelines had been finalized before the respective dabigatran approvals, and so the ACC/AHA/HRS document doesn't include guidance on the drug's use. Shrewdly, however, the CCS guidelines developers bet that it would be soon approved in Canada and went ahead and included dabigatran as an anticoagulation option. The European Medicines Agency has not approved the drug for AF, although in 2008 it authorized it for VTE prophylaxis in the setting of orthopedic surgery.
We recognized early on that dabigatran would probably be approved, and we did include it. But we pulled it out at the last minute.
"We had considered dabigatran when the committee first started," writing group chair Dr L Samuel Wann (Wisconsin Heart Hospital, Wauwatosa) told heartwire . "We recognized [early on] that dabigatran would probably be approved, and we did include it. But we pulled it out at the last minute because as the press deadline came forward, the FDA had not yet approved it."
Now that the drug is approved, he said, they can go with plan B: since the dabigatran part has already been finalized, they will release an update to the update. "That is in the final process of being approved by all the boards of the ACC and AHA, and I believe will be out soon after the first of the year."
Wann predicts any update relating to dabigatran will be straightforward since the indications for oral anticoagulation in AF haven't changed. So "the way the guideline will read is that dabigatran substitutes for warfarin except in patients with valvular heart disease. . . . The evidence that it prevents strokes at least as well as warfarin is quite convincing, and the updated guideline will reflect that."
Wann emphasized, however, that the dabigatran recommendations could still change, and have yet to get final approval from the sponsoring societies.
Wann acknowledges that the availability of dabigatran steals some of the thunder from one of the new update's recommendations, that the combination of aspirin and clopidogrel (Plavix, Sanofi-Aventis/Bristol-Myers Squibb) "might be considered" to cut the risk of stroke and other vascular events as an alternative to warfarin (class IIb, level of evidence B).
Many patients with AF who might have gone with the double-antiplatelet therapy instead of warfarin now have the dabigatran option, he observed, so the importance of aspirin-clopidogrel "will pale in comparison with the impact that dabigatran will have on the oral anticoagulation scene."
Other New Recommendations
Also in the update: the mainstreaming of catheter ablation for AF, which now "is useful" for maintaining sinus rhythm "in selected patients with significantly symptomatic, paroxysmal AF who have failed treatment with an antiarrhythmic drug and have normal or mildly dilated left atria, normal or mildly reduced LV function, and no severe pulmonary disease" (formerly a class IIa recommendation, level of evidence C, now class I, level of evidence A).
"The weight of evidence in controlled trials is now to the point where we can say this is a very good procedure for patients who have not responded to conventional drug therapy," Wann said.
Ablation also "is reasonable" for symptomatic persistent AF (class IIa, level of evidence A) and "may be reasonable" for symptomatic paroxysmal AF in patients with significant left atrial dilatation or with significant LV dysfunction (class IIb, level of evidence A)
Dronedarone turns out to be much safer than its first-cousin amiodarone but also less efficacious in terms of doing away with atrial fibrillation.
The guidelines update also states that there's "no benefit" (class III, level of evidence B) to achieving "strict" heart-rate control (<80 bpm at rest or <110 bpm during a six-minute walk) in patients who follow a rate-control as opposed to a rhythm-control strategy, compared with aiming for a lenient target of <110 bpm at rest.
"Rate control is still an important aspect of treating people with atrial fibrillation," Wann noted. "It's just that you don't need to exercise them and keep increasing the drugs until you get to a strict definition of success—in part because adding all of those drugs increases the number of hospitalizations and doesn't contribute to a sense of well-being on the part of the patients."
Rounding out the major new recommendations, dronedarone (Multaq, Sanofi-Aventis) "is reasonable" for cutting the risk of cardiovascular hospitalization in patients with paroxysmal AF or in patients with persistent AF who achieve sinus rhythm (class IIa, level of evidence B) but shouldn't be given to patients with NYHA class 4 heart failure or patients with decompensation within the last month, "especially" if they have an LVEF <35% (class III, level of evidence B).
Dronedarone will probably be widely used in AF, "with the caveat that [the ATHENA trial] showed it reduced hospitalization for AF and didn't necessarily do away with AF," Wann said. "Dronedarone turns out to be much safer than its first-cousin amiodarone but also less efficacious in terms of doing away with atrial fibrillation."
Wann had nothing to disclose. Disclosures for other writing committee members are listed in the paper.
Heartwire from Medscape © 2011 Medscape, LLC
Cite this: US Societies Bring Atrial-Fib Guidelines Almost Up-to-Date - Medscape - Jan 04, 2011.