CHA₂DS₂-VASc Score for Atrial Fibrillation Stroke Risk
- The CHA2DS2-VASc score is one of several risk stratification schema that can help determine the 1 year risk of a TE event in a non-anticoagulated patient with non-valvular AF.
- The CHA2DS2-VASc score, among other risk stratification schema, can be used to provide an idea of a patient’s risk for TE event.
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.
Helps with long-term stroke risk stratification for atrial fibrillation patients.
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One recommendation suggests a 0 score is “low” risk and may not require anticoagulation; a 1 score is “low-moderate” risk and should consider antiplatelet or anticoagulation, and score 2 or greater is “moderate-high” risk and should otherwise be an anticoagulation candidate.
- Consider not starting anticoagulation in patients with non-valvular AF and a CHA2DS2-VASc score of 0 as these patients had no TE events in the original study.
- For those patients in whom anticoagulation is considered, risk bleeding scores such as ATRIA can be used to determine the risk for warfarin-associated hemorrhage.
- Carefully consider all the risks and benefits prior to initiating anticoagulation in patients with non-valvular AF.
- Some guidelines suggest that aspirin monotherapy is not supported by evidence.