New tools for stroke prediction in atrial fibrillation

Evidence indicates that at least 25% of AF-related strokes are potentially preventable with adherence to evidence-based care, namely the use of the CHADS2, and now the more refined CHA2DS2-VASc risk stratification systems which use clinical risk factors to guide the prophylaxis decision. However, a body of evidence is growing that indicates these methods may provide relatively modest overall performance as predictors of stroke.

Dr. Hiren Shah

The results of newer studies using novel biomarkers outlined here indicates there is potential refinement to current clinical risk methodologies using biomarkers that reflect pathophysiological processes relevant to AF. In addition to stroke prediction, they may also predict cardiac death and delayed AF in patients with stroke, a condition that often goes unrecognized.

There are three important considerations to these studies. Since the results were extrapolated from the ARISTOTLE trial, all patients were on anticoagulation, making it difficult to translate its findings on stroke risk and cardiac death. Thus, clear validation is needed for these novel biomarkers in settings in which no anticoagulation has been given within the study design before their use is incorporated into current guidelines.

Second, clinical trial settings are not always replicated in real world populations where patient inclusion criteria can differ significantly. For instance the very elderly, who have a higher stroke risk, were not represented in these studies.

Finally, although more robust risk-stratification systems have the potential to improve outcomes, it is important to remember ensuring their use is not guaranteed. Studies indicate that on average, only 50% of patients with AF are on risk appropriate prophylaxis.

Dr. Hiren Shah is medical director of the medicine and cardiac telemetry hospitalist unit at Northwestern Memorial Hospital in Chicago.