New AF update calls for greater focus on identifying “truly low risk” patients

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In a focused update of its 2010 guidelines for the management of atrial fibrillation, the European Society of Cardiology (ESC) “strongly recommends” a practice shift towards initial identification of patients at “truly low risk” of stroke.

Presenting the new guideline recommendations at the annual meeting of the ESC (25–29 August, Munich, Germany), Gregory YH Lip, University of Birmingham Centre for Cardiovascular Sciences, City Hospital, Birmingham, UK, told delegates that the ESC guidelines now recommend that the focus should be on identifying patients with atrial fibrillation who have a truly low risk of stroke-“instead of being obsessed with trying to identifying the high-risk patients” as such patients can be managed without the need for any antithrombotic therapy.

Lip explained that the ESC guidelines now formally advocates using the “CHA2DS2-VASc” (Congestive heart failure, hypertension, age ≥75 years [doubled], diabetes, stroke [doubled], vascular disease, age 65–74 years, and sex category [female]) score for assessing stroke risk rather than the older CHADS2 score. Indeed, the CHADS2 score may underestimate the risk of stroke in many patients. He said: “We looked at the 17,000 patients [using data from a Danish cohort] who could be classed as having a CHADS2 score of 0 but when you then subdivided them by CHA2DS2VASc, you could see that the stroke rate varied between 0.8% per year and going up as high as 3.2% per year. A 3.2% per year event rate in the patient with a CHADS2 score of 0? Surely, that is not low risk.” He added that anyone who assumed a patient with atrial fibrillation and a CHADS2 score of 0 was at low risk of stroke was “kidding themselves” and leaving the patient at “substantial risk of having a fatal and devastating stroke.”

Thus, the ESC guideline now advises that patients who do have a truly low risk of stroke (eg, age<65 and lone atrial fibrillation, (irrespective of gender) or CHA2DS2-VASc score=0) should not receive any antithrombotic therapy, and other patients with one or more risk factors for stroke should receive effective stroke prevention, which is essentially oral anticoagulation therapy.

As well as adopting the CHA2DS2-VASc risk score, another major change in the update is the choice of preferred oral anticoagulation therapy. Update authors John Camm, Division of Clinical Sciences, St George’s University of London, London, UK, and others reported in the European Heart Journal that novel anticoagulants (dabigatran, Pradaxa, Boehringer Ingelheim; rivaroxaban, Xarelto, Bayer Healthcare; apixaban, Eliquis, Bristol-Myers Squibb and Pfizer) are “broadly preferable” to warfarin for the prevention of stroke in patients with atrial fibrillation.

The authors wrote that this was because the novel anticoagulants, so far, “have all shown non-inferiority compared with vitamin K antagonists [ie, warfarin] with better safety considerations, consistently limiting the number of intracranial haemorrhages”. They added that, due to limited data for the novel anticoagulants, “strict adherence” to the drugs’ approved indications and “careful post-market surveillance” was strongly recommended. However, Camm et al did not make any suggestions as to which novel anticoagulant should be used because they said that it would be “inappropriate” given the lack of head-to-head trials in this area.

The ESC guideline also recommends use of the HAS-BLED (Hypertension, Abnormal kidney and/or liver function, Stroke, Bleeding, Labile INR, Elderly, and Drugs and/or Alcohol) score for assessing bleeding risk in patients with atrial fibrillation. Lip explained that new evidence shows that the HAS-BLED score outperforms other bleeding risk scores (including the HEMORR(2)HAGES and ATRIA scores) and it has a good predictive value for intracranial bleeding-the most feared complication of antithrombotic therapy. In his presentation at the ESC, he said: “A high HAS-BLED score per se is not to stop anticoagulation, but is used to ‘flag up’ the patients who are at potential high risk for bleeding for whom more regular review and follow-up is recommended, and efforts to correct the common reversible risk factors for bleeding (eg, labile INRs if on warfarin, uncontrolled blood pressure, concomitant NSAID use, etc) within the HAS-BLED score can be made.” He added, the score “helps the clinician think about bleeding risk in an informed manner rather than relying on guesswork.”

In addition to its recommendations on oral anticoagulation therapy, the ESC update also reviewed left atrial appendage (LAA) closure, with Camm et al reporting that antithrombotic therapy in patients with atrial fibrillation “even after removal or closure of the LAA” may be necessary due to evidence that the LAA is “probably not the only left atrial region where thrombi can potentially originate”. The authors do state that concept of LAA closure “seem reasonable” but add “the evidence and safety is currently insufficient to recommend these approaches for any patients other than those in whom long-term oral anticoagulation is contraindicated.”

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