“CRYSTAL-AF represents the state of the art for cardiac monitoring in cryptogenic stroke patients and makes the AAN guidelines obsolete,” said Dr. Bernstein. “[The study] shows that even intermediate-term monitoring (less than one month) will miss the majority of atrial fibrillation in this population, and that most of the atrial fibrillation we find with long-term (greater than one year) monitoring is likely to be clinically significant.”
The AAN guideline includes “no discussion of truly long-term monitoring … which is unfortunate,” he added. Nevertheless, “anything that gets neurologists thinking about long-term cardiac monitoring is likely to be beneficial.”
Guideline Recommends Anticoagulants for Stroke Prevention
The AAN guideline also provides general recommendations on the use of NOACs as alternatives to warfarin. The authors note that in comparison with warfarin, rivaroxaban is probably at least as effective, and dabigatran and apixaban may be more effective. In addition, although apixaban is likely to be more effective than aspirin, it is associated with a similar risk of bleeding. NOACs’ advantages over warfarin include an overall lower risk of intracranial hemorrhage and their elimination of the need for routine anticoagulant monitoring.
Clinicians have the following options available, according to the AAN guideline: warfarin (INR, 2.0 to 3.0), dabigatran (150 mg bid), rivaroxaban (15 to 20 mg/dL), apixaban (2.5 to 5 mg bid), and triflusal (600 mg) plus acenocoumarol (INR, 1.25 to 2.0). If a patient is already taking warfarin and is well controlled, he or she should remain on that therapy and not switch to a newer oral anticoagulant, said the authors.
The combination of clopidogrel and aspirin is probably less effective than warfarin, but probably better than aspirin alone, according to the guideline. The risk of hemorrhage, however, is higher with clopidogrel and aspirin.
The combination of triflusal and acenocoumarol is “likely more effective” than acenocoumarol alone, said the authors. Triflusal is available in Europe, Latin America, and Southeast Asia, and acenocoumarol is available in Europe.
The document is not intended to dictate which treatment to use, Dr. Culebras explained. “The guideline leaves room on purpose for clinicians to use their judgment,” he said. “The overall objective of the guideline is to reduce therapeutic uncertainty and not to issue commandments for treatment.”
Although Dr. Bernstein criticized the guidelines for not recommending anticoagulants strongly enough, the recommendations on anticoagulant choice are “reasonable in that they impute potential clinical profiles of patients who might particularly benefit from one NOAC over another, without making a claim that these recommendations are based on solid data,” he said. “This [approach] reflects how doctors make decisions when we don’t have direct comparative studies, and I think that is helpful.”
—Sara Freeman