CHA(2)DS(2)-VASc versus CHADS(2) for stroke risk assessment in low-risk patients with atrial fibrillation: a pilot study from a single center of the NCDR-PINNACLE registry.

The CHADS(2) score is widely used to assess the risk of stroke in patients with atrial fibrillation (AF). Patients with score of 0 and 1 are considered 'low risk' and are often treated with aspirin. In a Danish Study, the CHA(2)DS(2)--VASc score was shown to identify low and high-risk subgroups among patients with CHADS(2) score of 0 and 1, with annual risk ranging from 0.84 to 8.18%. This study seeks to assess whether using CHA(2)DS(2)--VASc score will identify high-risk subset of patients with low CHADS(2) scores in an American population. This pilot study examined data from our cardiology fellowship ambulatory clinics from January 2009 to May 2012 using the NCDR-PINNACLE registry. Each cardiology fellow entered patients' data using on-line software developed by the American College of Cardiology. Among 2,048 patients followed at our clinics, 478 had AF. Of those, 161 patients had CHADS(2) score of 0 (44 patients) or 1 (117 patients). Calculating the CHA(2)DS(2)--VASc score in these patients, 12 (7.4%) had score of 0, 50 (31.1%) had score of 1, 66(41%) had score of 2, 31 (19.3%) had score of 3 and 2 (1.2%) had score of 4. Using original CHADS(2) recommendation, warfarin would not be strongly recommended in any of these patients. Utilizing the CHA(2)DS(2)--VASc score, 61.5% of the 161 patients would have a score of 2 or more signifying increased risk where anticoagulation may be indicated. Compared to CHADS(2), CHA(2)DS(2)--VASc may more precisely predict the risk of stroke and anticoagulation strategy in low-risk patients with non-valvular AF.