The CHA2DS2-VASc Score (Birmingham 2009) was developed after identifying additional stroke risk factors in patients with atrial fibrillation.
- Validation study included 1,084 patients with non-valvular AF, not on anticoagulation, over age 18 with EKG or Holter diagnosed AF in the ambulatory and hospital settings from 182 hospitals in 35 countries from 2003 to 2004 and had known thromboembolic status at 1 year from the Euro Heart Survey database.
- End point used was stroke or other thromboembolic event.
- Used previously developed Birmingham 2009 schema, under the acronym CHA2DS2-VASc.
- Study showed that as CHA2DS2-VASc score increased, rate of thromboembolic event within 1 year in non-anticoagulated patients with non-valvular AF increased as well.
- Considered score of 0 to be low risk for TE events (none seen in cohort at one year), score of 1 intermediate risk (0.6% rate at 1 year), and greater than 1 high risk (3% rate at 1 year).
Points to keep in mind:
- 31% of the patients in their original study group were lost to follow-up at one year and thus were not included in the analysis. These patients could have had thromboembolic events, causing them to be lost to follow-up.
- There was no statistically significant difference found between the CHA2DS2-VASc and CHADS₂ risk stratification schema in predicting TE events.
- None of the included patients were anticoagulated. Those at particularly high risk for a TE event may have been already anticoagulated by their PMD, potentially skewing the TE rates.
- A subsequent study examining the performance of CHA2DS2-VASc in predicting TE events on anticoagulated patients also identified CAD and smoking as potential additional risk factors for TE in this subset of patients. However, that study also did not show a statistical difference in the predictive avarious risk stratification abilities of the scores.
