Which risk factor assessment algorithms have been developed to aid in making anticoagulation decisions for patients with atrial fibrillation (Afib) (AF)?

Updated: Nov 18, 2019
  • Author: Lawrence Rosenthal, MD, PhD, FACC, FHRS; Chief Editor: Jeffrey N Rottman, MD  more...
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Answer

Several risk factor assessment algorithms have been developed to aid the clinician on decisions on anticoagulation for patients with AF. The CHADS2 index (Cardiac failure, Hypertension, Age ≥75 years, Diabetes, Stroke or transient ischemic attack [TIA]) was widely used previously [65] ; however, multiple more recent studies have proven the superiority of the CHA2DS2-Vasc score over the CHADS2 score in predicting the risk of thromboembolism in patients with AF, particularly for participants with low to intermediated CHADS2 scores (0-1). [44, 66]

The CHA2DS2-Vasc score uses a point system to determine yearly thromboembolic risk. Two points are assigned for a history of stroke or TIA, thromboembolism, or age of 75 years or older, and one point is given for age 65-74 years or a history of hypertension, diabetes, heart failure, arterial disease (coronary artery disease, peripheral arterial disease, or aortic plaque), or female sex. The predictive value of this scoring system was evaluated in 90,490 elderly patients with nonvalvular AF who were taking warfarin therapy. [67] An increase in CHA2 DS2-VASc score was associated with serial increase in the risk of stroke (see Table 1 below).

Table 1. Stroke Rate in Patients with Nonvalvular Atrial Fibrillation not Treated with Anticoagulation [67] (Open Table in a new window)

CHA2 DS2-VASc Score

Unadjusted Stroke Rate (%/y)

0

0.2

1

0.6

2

2.2

3

3.2

4

4.8

5

7.2

6

9.7

7

11.2

8

10.8

9

12.2


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