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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From the Creator
Why did you develop the CHA₂DS₂-VASc score? Was there a clinical experience that inspired you to create this tool for clinicians?
The availability of Non-Vitamin K Antagonist Oral Anticoagulants (NOACs, previously referred to as new or novel oral anticoagulants, has led to a major change in the landscape for stroke prevention in atrial fibrillation (AF). Clinicians are also getting better at understanding how to manage warfarin, recognizing the importance of the average time in therapeutic range (TTR). New data are also re-emerging on the poor evidence for the efficacy and safety of aspirin for stroke prevention in AF. The older CHADS2 Score was designed to identify “high risk” patients for warfarin, but many common (and important) stroke risk factors in AF are not included within the CHADS2. CHA₂DS₂-VASc was developed to be more inclusive of common stroke risk factors/modifiers. Numerous validation studies have shown that CHA2DS2-VASc is as good as - or possibly better - than CHADS2 at predicting high risk patients, but CHA2DS2-VASc is certainly best at predicting the “low risk” patients.
What pearls, pitfalls and/or tips do you have for users of the CHA2DS2-VASc score? Are there cases when it has been applied, interpreted, or used inappropriately?
In older guidelines, the focus was to identify AF patients at ‘high risk’ of stroke, to target for warfarin treatment; however, many studies have shown under-use of warfarin amongst such ‘high risk’ patients. In 2014, the AHA/ACC/HRS guidelines recommended used of the CHA2DS2-VASc score as the stroke risk assessment tool of choice.
How best to approach stroke prevention in AF by using the CHA2DS2-VASc score?
In 2012, the European Society of Cardiology (ESC) guidelines recommended a clinical practice shift, to initially focus on the identification of ‘truly low risk’ patients who do not need any antithrombotic therapy. These low risk patients are those CHA2DS2-VASc score of 0 (male) or 1 (female). Subsequently, the next step is to offer effective stroke prevention (ie. Oral anticoagulation) to those with ≥1 additional stroke risk factors.
What recommendations do you have for health care providers once they have the CHA2DS2-VASc score result? Are there any adjustments or updates you would make to the score given recent changes in medicine?
Use the approach recommended in the 2012 ESC or NICE guidelines - first step, identify LOW RISK patients, i.e., CHA₂DS₂-VASc score of 0 (males) or 1 (females), who do not need any antithrombotic therapy, Next or subsequent step is to offer effective stroke prevention to all others with 1 or more additional stroke risk factors. As per the NICE guidelines, aspirin should not be used for stroke prevention in AF - it is minimally effective, not safe nor is it cost effective.
Have you found colleagues adjusting who receives which type of anticoagulant based on the CHA2DS2-VASc score rather than the CHADS2 alone?
Definitely. A CHADS2 of 0 is NOT low risk, and stroke rate can be as high as 3.2%/year if untreated (Olesen et al, Thromb Haemostat 2012). Using CHA₂DS₂-VASc can further refine stroke risk stratification of those with a CHADS2 score of 0 to identify those who would still substantially benefit from oral anticoagulation.
About the Creator
Gregory Lip, MD, is the David A. Price-Evans Chair in Cardiovascular Medicine at the University of Liverpool and an honorary consultant cardiologist at Liverpool Heart and Chest Hospital. He is also a researcher in the Aalborg Thrombosis Research Unit at Aalborg University in Denmark. Dr. Lip is one of the world’s leading experts in risk stratification of atrial fibrillation, with his research directly informing the widely-used CHA₂DS₂-Vasc and HAS-BLED Scores.
To view Dr. Gregory Lip's publications, visit PubMed