Comparison between CHADS₂ and CHA₂DS₂-VASc score in a stroke cohort with atrial fibrillation

Background and purpose: In patients with atrial fibrillation (AF), stroke risk stratification schemes have been developed to optimize antithrombotic treatment. The CHADS₂ score is frequently used but has limitations. The CHA₂DS₂-VASc score improves risk prediction. Our objectives are to describe CHADS₂ and CHA₂DS₂-VASc score distribution in a cohort of patients with AF and first-ever ischaemic stroke (FIS) and to identify differences in embolic risk stratification. Methods: Our cohort included 589 patients with FIS, previous modified Rankin score ≤ 3, and non-valvular AF. We recorded demographic data, vascular risk factors, and antithrombotic pre-treatment. The CHADS₂ and CHA₂DS₂-VASc scores were calculated according to clinical status before stroke onset. Results: In 186 (31.6%) patients, AF was previously unknown. Of patients with known AF and CHADS₂ ≥2 (n = 320), only 103 (32.2%) were taking anticoagulants; more than half of these patients had an INR <2. The CHADS₂ score placed 142 (24.1%) patients in the low-intermediate risk (score ≤ 1) category compared with 21 (3.6%) with CHA₂DS₂-VASc, P < 0.001. Applying CHA₂DS₂-VASc reclassified 121 (85.2%) subjects in the CHADS₂ low-intermediate risk category as high risk (≥2), an indication for anticoagulants. Of the 21 patients who suffered a stroke despite their low CHA₂DS₂-VASc score (≤1), seven (33.3%) reported alcohol overuse, and six (28.5%) had a concomitant stroke etiology. Conclusions: About 25% of FIS patients with AF had a CHADS₂ score ≤ 1. Despite the high CHADS₂ score of our population, few patients received the recommended antithrombotic treatment according to their thromboembolic risk. Using the CHA₂DS₂-VASc schema significantly increased the percentage of patients indicated for anticoagulation.