AHA/ACC: New performance measures for AF

February 18, 2008

Boston,MA- The AHA and the ACC have jointly issued clinical performance measures for adults with nonvalvular atrial fibrillation (AF) or atrial flutter, which are published concurrently February 18, 2008 in the Journal of the American College of Cardiology[1] and Circulation. Chair of the writing committee and lead author of the paper, Dr NA Mark Estes (Tufts, Boston, MA), told heartwire there were three main measures outlined in the document that aim to help physicians treating people with nonvalvular AF in the outpatient setting.

"First, doctors should be risk-stratifying patients for stroke and other embolic events; second, they should employ warfarin [Coumadin, Bristol-Myers Squibb] therapy unless it is contraindicated; and third, they need to strictly monitor the international normalized ratio [INR] of patients taking warfarin," he says.

We want this to be a metric by which physicians can assess their performance relative to what are considered the best re commendations for AF out there.

"We want this to be a metric by which physicians can assess their performance relative to what are considered the best recommendations for AF out there," he adds. "We really extracted what we consider to be the three things that are best supported by the evidence and that are very clearly defined. I think that these can be incorporated into the routine evaluation of every patient with AF by ancillary staff, by the patients themselves, and ultimately by electronic medical records, so this will not be an onerous, time-consuming task for the physician."

A particular focus on anticoagulation

Estes explained that new clinical guidelines for the treatment of AF were published around 18 months ago, in August 2006. "Importantly, these were guidelines that went through a very rigorous process of reviewing all the evidence—not only ACC and AHA, but the ESC also participated and endorsed these guidelines," he notes.

So physicians know in theory what they should be doing, he says, but the question is whether they are doing it. The new document contains paper-based specifications and assessment tools that are also available online to aid doctors in the management of patients with AF, he says.

"The committee of the AHA/ACC and several other groups looked at the best available evidence relative to the management of AF, and we came up with a particular focus on anticoagulation for patients with AF." He stresses that the current advice applies only to patients with nonvalvular AF or atrial flutter and only in the outpatient setting.

With any patient with AF, the first thing every physician should do is to risk- stratify the patient for stroke and other embolic events, says Estes, explaining that there are a number of conditions that have consistently emerged as independent risk factors for ischemic stroke associated with nonvalvular AF.

Risk factors for stroke in patients with AF

Less validated or weaker risk factors Moderate-risk factors High-risk factors
Female gender Age >75 years Prior stroke, TIA, or systemic embolism
Age 65 to 74 years Hypertension  
Coronary artery disease Heart failure  
Thyrotoxicosis LVEF <35%  
  Diabetes mellitus  

The performance measures also highlight the use of a standard risk-assessment score, called CHADS2, Estes notes, where "C stands for congestive heart failure, H for hypertension, A for age >75 years, D for diabetes, and the S2 is a prior ministroke, transient ischemic attack [TIA], or a frank stroke." CHADS2 is based on a point system in which 2 points are assigned for a history of TIA or stroke and 1 point each for recent heart failure, history of hypertension, age over 75 years, and diabetes mellitus.

Use warfarin appropriately

The second performance measure relates to the use of warfarin, which has been shown to decrease the risk of stroke, he notes.

Anticoagulation with a vitamin-K antagonist such as warfarin is recommended for patients with more than one moderate-risk factor. Aspirin is recommended as an alternative to warfarin in low-risk patients and in those with contraindications to warfarin.

"In particular, physicians need to use warfarin appropriately in individuals who are at risk for stroke and who don't have a contraindication to warfarin." And the third recommendation—"which is very straightforward—is that patients need to be monitored on warfarin, with at least monthly assessment of INR once anticoagulation is stable."

"So each physician should look at the risks and benefits and use warfarin in patients at high risk for stroke who don't have a contraindication to it," he surmises.

Antithrombotic therapy for patients with nonvalvular AF

Risk category Recommended therapy
No risk factors Aspirin 81 to 325 mg daily
One moderate-risk factor Aspirin 81 to 325 mg daily or warfarin (INR to 2.0-3.0, target 2.5)
Any high-risk factor or more than one moderate-risk factor Warfarin (INR to 2.0-3.0, target 2.5)
Hope that performance measures will improve outcomes

"Essentially, what we are trying to do is to give the physician a practical tool that they can fill out in their office, and that really is the essence of these performance measures," Estes notes.

"Ultimately, it's probable that these will be linked with electronic medical records so that this information can be extracted automatically from the physician record, and there will be a mechanism of collecting these data in the individual practice. Then, if one is falling short on any of these measures, it will be an indication that physicians need to train their staff and/or modify their own procedures to follow the guidelines."

Then, it is hoped, in the future, it will be possible to judge whether these clinical performance measures have improved outcomes, says Estes: "We hope to see whether patients have fewer strokes, a better quality of life, and live longer, but that tool is not clearly defined as yet."


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