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How to identify AF patients at low stroke risk
In a presentation at the 2015 AHA Fall Conference, Daniel E. Singer, MD, spoke about identifying patients with an increased bleeding risk with the long-term use of oral anticoagulants and whether or not there is a benefit in those cases.
Although the risk of ischemic stroke is high enough to warrant anticoagulation in most patients with atrial fibrillation (AF), there are some patients at low enough risk of ischemic stroke for whom the benefits of anticoagulation may not outweigh its risks.
Given the increased bleeding risk with long-term use of oral anticoagulants (OAC), it makes sense to identify patients for whom the use of OAC has a low or very low net clinical benefit, according to Daniel E. Singer, MD, professor of medicine at Harvard Medical School, during his talk entitled “Controversies in Risk Assessment: What is the Best Method to Identify the Low-Risk Patient?” delivered at the American Heart Association (AHA) meeting.
Defining net clinical benefit of oral anticoagulation use as the difference between the absolute reduction in risk of ischemic stroke and the absolute increase in the risk of major bleeding (mainly due to intracranial hemorrhage), Singer emphasized that a proxy for net clinical benefit is determining the risk of ischemic stroke in a patient not on anticoagulation.
Related: The complexity of atrial fibrillation
What is needed, Singer said, was for future AF guidelines to “focus more rigorously on estimating patient stroke risk and consider the use of risk models that incorporate formal weighting of risk factors, in particular, giving appropriate weight to increasing age.”
As of now, current guidelines fail to focus on absolute stroke risk and its corresponding net clinical benefit, he said. Instead, recommendations on anticoagulation use are based primarily on CHADS-VASc point scores despite great variation in stroke rates at given point scores across AF cohorts. This, he said, makes the relationship between stroke risk point scores and stroke risk ambiguous.
In addition, Singer said, “stroke rates within a given CHADS-VASc point score category differ greatly according to the risk factors indicated.”
He highlighted that older age and more risk factors are a stronger indication than strict CHADS-VASc point scores to determine oral anticoagulation use. “If you choose to use CHADS-VASc, appreciate that a score of 1 is heterogeneous,” he said. “Individuals younger than 65 with CHADS-VASc of 1 are not likely to gain much net benefit from OAC; for individuals 65+, OAC is indicated,” Singer said.
