Risk Stratification for Stroke in Atrial Fibrillation: A Critique

Ammar M. Killu; Christopher B. Granger; Bernard J. Gersh


Eur Heart J. 2019;40(16):1294-1302. 

In This Article

Abstract and Introduction


Despite the demonstrable success of oral anticoagulants in reducing the rate of stroke in patients with atrial fibrillation, they continue to be seriously underutilized. Indications for their use as stated in the guidelines incorporate a number of risk score algorithms, the most widely used being the CHA2DS2-VASc score. Nonetheless there are several limitations to the various scores currently in clinical use and a critique of these is the focus of this review. In this review we discuss the pathophysiology of atrial fibrillation and its role in thromboembolic stroke risk. We amalgamate this with the basis of major professional society anticoagulation recommendations with regards to the strengths and limitations of current risk stratification strategies and discuss gaps in our current evidence base and next steps to address those gaps.


Atrial fibrillation (AF) is the most common sustained arrhythmia encountered in clinical practice with an increasing global incidence and prevalence.[1] Given its burden and associated complications, AF portends a considerable public health problem. Studies have shown that patients with AF have impaired quality of life and increased mortality rates.[2,3] Furthermore, there is an association of AF with impaired cognitive functioning.[4] The most common and dreaded consequence, however, is thromboembolic stroke. To mitigate this, anticoagulation has played a major role in AF management. Warfarin is associated with a two-thirds reduction in stroke rate compared with placebo in numerous trials.[5] While vitamin K antagonists were the mainstay of therapy for decades, non-vitamin K ('novel' or 'direct') oral anticoagulants (NOACs) are increasingly used as agents that are modestly moreeffective at preventing stroke, and substantially safer regarding intracranial haemorrhage, than warfarin.

In this review, we discuss the pathophysiology of AF and the related risk of thromboembolic stroke. Further, we review the basis of major societal anticoagulation recommendations with regards to strengths and limitations of current risk stratification strategies and discuss gaps in our evidence base.