Although the CHADS₂ score has proven useful over the years, there have nevertheless been attempts to build upon it to improve its predictive value. The CHA₂DS₂-VASc score is such an evolution (Figure 12; see also Hylek, Figure 5).[13] CHA₂DS₂-VASc has the same elements as CHADS₂ score, but with several additions:

• In addition to congestive heart failure as in CHADS₂, the newer score adds a depressed left-ventricular ejection fraction (LVEF <35%).
• Age >75 years is now assigned a risk index score of 2 (instead of 1).
• In addition to stroke and TIA, the newer score adds systemic embolism, still with an index risk score of 2.

Finally, the new score adds 3 other factors:

• The presence of vascular disease (prior myocardial infarction, peripheral disease, or aortic plaque).
• A lower age category, 65-74 years.
• Gender (female gender is assigned an index risk score value of 1).

This final factor (gender) goes back to a point made in Figure 5 that is sometimes confusing. In female patients with AFib the risk of stroke is higher than in males with AFib – but with increasing age, although the prevalence of AFib tends to be higher in males, a lower percentage of males survive into that very elderly stage, and therefore the aggregate population risk of stroke appears to be higher in elderly women because more of them are surviving.

The CHA₂DS₂-VASc score builds on the older CHADS₂ score by incorporating additional risk categories, but the final risk calculation is similar. Thus as with CHADS₂, a low risk is defined as 0–1 and moderate-to-high risk is defined as a calculated risk score ≥2. These are scores to determine the risk of ischemic or cardioembolic stroke, but again, all of these risk bins are relative demarcations on what is actually a continuum of risk.