Ischemic stroke is an important complication of atrial fibrillation (AF) and risk stratification schemes that predict thromboembolic events in patients with AF are important for indicating antithrombotic therapy in order to prevent stroke occurrence (1). The CHA2DS2-VASc score (2) is the most complete stratification scheme, which was recently recommended by the European Society of Cardiology (1). Another score scheme, the CHADS2 (3) is easy to apply and widely used but may not be as efficacious.
Of 215 patients admitted with ischemic stroke at the emergency department of Hospital Israelita Albert Einstein (a tertiary hospital in São Paulo, Brazil) between September 2004 and March 2006, we found 35 patients with AF and ischemic stroke. We then applied parameters previous to stroke admission to these 35 patients using the CHADS2 and CHA2DS2-VASc scores.
Nine of the 35 patients scored one in CHADS2 score (25·5%), and were reassessed by CHA2DS2-VASc score; two had CHA2DS2-VASc score of two; five had CHA2DS2-VASc score of three, and two had CHA2DS2-VASc score of four.
Factors that increased scoring were: having an age range of 65–74, age ≥75 years, female gender, and coronary artery disease. These factors are associated to increased risk of ischemic stroke in patients with AF (4, 5) and are not considered in CHADS2. Accordingly, we also had a statistically significant increase in AF prevalence in older patients, mainly 80 years or older (P<0·01, Fisher exact test, significance level 5%) vs. younger patients.
All patients with a CHADS2 score of one were not under anticoagulation but in retrospect had CHA2DS2-VASc score ≥2, which indicated the need for oral anticoagulation.
Risk stratification using CHA2DS2-VASc score would have optimized indication for oral anticoagulation in our patients and hence reduced their risk of stroke. We recommend the complementation of risk stratification by applying CHA2DS2-VASc score in all patients with CHADS2 scores of zero and one.