CHADS₂ Score Calculation
This patient has a CHADS₂ score of 5 (Answer D).
Score Components Breakdown
The CHADS₂ scoring system assigns points as follows 1:
C (Congestive Heart Failure): 1 point
- This patient has clear clinical evidence of heart failure with elevated JVP, S3 gallop, and bibasal crackles 1
H (Hypertension): 1 point
- Blood pressure of 150/90 mmHg confirms hypertension 1
A (Age ≥75 years): 1 point
- Patient is 64 years old, so does NOT receive this point 1
D (Diabetes mellitus): 1 point
- Patient has documented diabetes mellitus 1
S₂ (Prior Stroke or TIA): 2 points
- History of stroke assigns 2 points (doubled weight) 1
Total Score Calculation
Adding the components: 1 (CHF) + 1 (HTN) + 0 (age <75) + 1 (DM) + 2 (stroke) = 5 points 1
Clinical Significance
A CHADS₂ score of 5 indicates very high stroke risk with an adjusted annual stroke rate of approximately 12.5% per year without anticoagulation 1. This score mandates oral anticoagulation therapy with warfarin (INR 2-3) or direct oral anticoagulants 1.
Common Pitfall
The critical error to avoid is miscounting the age criterion. The CHADS₂ score assigns 1 point only for age ≥75 years 1. Since this patient is 64 years old, he does not meet the age threshold and receives 0 points for age. The CHA₂DS₂-VASc score (a newer scoring system) would assign 1 point for age 65-74 years, but that is not what this question asks 2.