New ACC/AHA/ESC Guidelines for the Management of Atrial Fibrillation: Highlighting St

[EVP]

Уважаемые коллеги! Вышел новый гайдлайн по лечению фибрилляции предсердий. В частности для неврологов интересна информация по профилактике инсульта. [Ссылки доступны только зарегистрированным пользователям ]

Atrial Fibrillation Expert Column
New ACC/AHA/ESC Guidelines for the Management of Atrial Fibrillation: Highlighting Stroke Prevention and Catheter Ablation
Posted 08/25/2006

Practice Point

The mortality rate in AF patients is approximately twice that in persons who are in normal sinus rhythm, and increases with age. AF patients also have a higher long-term risk of both heart failure and embolic stroke. In fact, AF is an independent risk factor for stroke. According to the ACC/AHA/ESC guidelines, the rate of ischemic stroke in patients with nonvalvular AF is about 2 to 7 times that of people without AF, and the risk increases dramatically as patients age. In the Framingham Heart Study by Wolf and colleagues,[3] the annual risk of stroke attributable to AF was 1.5% in participants aged 50-59 years and 23.5% in those aged 80-89 years.

Anticoagulation therapy is essential in patients with AF to reduce the risk of embolic stroke; however, there is some question about when warfarin (Coumadin) should be used in moderate- to low-risk AF patients.

Recommendations for anticoagulant therapy differ between the 2001 and 2006 guidelines. In 2001, the guidelines recommended using several patient characteristics (including age, gender, heart disease risk, and concurrent conditions) to determine proper antithrombotic therapies. The new guidelines, however, place more emphasis on stroke risk as the primary means to determine the need for anticoagulants, regardless of whether the patient is in sinus rhythm.

Criteria for Antithrombotic Therapies

Medscape: Is placing more emphasis on stroke risk as the primary means to determine the need for anticoagulant therapy a positive change?

Dr. Calkins: Yes, I think it is a positive change. The problem with the old guidelines was that different organizations published their own anticoagulation guidelines, and each one had slightly different cutoffs for when a patient should be receiving warfarin. Interpreted even in a very conservative fashion, those previous guidelines would lead to the conclusion that any patient over 65 years of age who has at least 1 risk factor for stroke should be getting warfarin. This means that huge numbers of otherwise healthy patients, when they reached the age of 65 years, required a discussion about warfarin and the need for anticoagulation monitoring, which is an enormous lifestyle change and commitment.

The new guidelines are much clearer about who are the highest-risk patients. According to the new guidelines, patients with prior stroke, or transient ischemic attack (TIA), or with rheumatic heart disease are at the highest risk for stroke ( Table 1 ), and they clearly need warfarin. But for patients at lower risk, no longer is 1 moderate risk factor enough to justify warfarin; these patients require ≥ 2 of these less severe risk factors before warfarin therapy should be considered.

The new guidelines also provide the full CHAD (Cardiac Failure, Hypertension, Age, Diabetes, and Stroke) scoring system, and they clearly specify when risk factors indicate that aspirin is sufficient and when risk factors suggest a patient is a candidate for warfarin. As shown in Table 2 , aspirin is sufficient in an AF patient with no other risk factors for stroke. If there is 1 moderate risk factor, either aspirin or warfarin can be used, according to patient preference. Warfarin is clearly indicated if a patient has 1 high risk factor or ≥ 1 moderate risk factor.

I commend the guideline committee on a superb job of narrowing risk and anticoagulant strategy, because otherwise a large number of patients would be put on warfarin. As much as we don't want patients to have strokes, we also don't want to put massive numbers of patients on warfarin when the stroke risk is only marginal or borderline. A lot of patients at the age of 65 years, and even in their early 70s, are still very active, and committing a patient like that to warfarin just because they reach age 65 years is a fairly big step to take.
Anticoagulation Therapy in Moderate-Risk Patients

Medscape: For moderate-risk patients, the guidelines give some leeway as far as whether to use aspirin or warfarin. How do you decide which therapy is appropriate for the moderate-risk patient?

Dr. Calkins: It really depends on patient preference. I have the 'anticoagulation discussion' with all of my AF patients who are eligible for warfarin. We talk about the benefits and risks of warfarin, and patients generally react in 1 of 2 ways. Some patients are incredibly frightened by the notion of a stroke, either because a family member has had a stroke or they have a friend who experienced a stroke, and they tend not to have a problem with warfarin clinics and long-term follow-up. These patients will choose to take warfarin even though their stroke risk is not high.

But most patients opt for the opposite: They strongly dislike taking medications and do not like the idea of going in monthly or weekly to get their INR level checked. With these patients, if you tell them their stroke risk is fairly low and there isn't an enormous difference between the 2 treatment options in terms of outcomes, they are likely to choose aspirin therapy and avoid warfarin clinic visits. I always will document that discussion with the patient, noting that we have talked about the risks and benefits of warfarin therapy and they have elected to proceed with a certain approach; I also include the patient's reasoning behind that decision.

Table 1. ACC/AHA/ESC 2006 Guidelines: Risk Factors for Stroke

Less Validated/Weaker Risk Factors

Female gender
Age 65-74 yrs
Coronary artery disease
Thyrotoxicosis

Moderate Risk Factors

Age ≥ 75 yrs
Hypertension
Heart failure
LVEF ≤ 35%
Diabetes mellitus

High Risk Factors

Previous stroke, TIA, or embolism
Mitral stenosis
Prosthetic heart valve

LVEF = left ventricular ejection fraction; TIA = transient ischemic attack

Table 2. ACC/AHA/ESC 2006 Guidelines: Recommended Therapies According to Stroke Risk

Risk Category Recommended Therapy
No risk factors Aspirin, 81-325 mg daily

One moderate risk factor Aspirin, 81-325 mg daily, or warfarin (INR 2.0-3.0, target 2.5)

Any high risk factor or ≥ 1 moderate risk factor Warfarin (INR 2.0-3.0, target 2.5)*

*If mechanical valve, target INR greater than 2.5

INR = international normalized ratio