A 62-year-old woman with newly diagnosed atrial fibrillation is being evaluated for stroke risk. She has hypertension, diabetes, and a prior stroke 2 years ago. A 55-year-old man with paroxysmal atrial fibrillation has no structural heart disease, normal blood pressure, and no prior thromboembolic events. Which finding best distinguishes the stroke risk profile between these two patients and guides anticoagulation intensity?

Explanation

## CHA₂DS₂-VASc Score: The Discriminator for Stroke Risk in AF ### Why CHA₂DS₂-VASc Distinguishes Risk **Key Point:** The **CHA₂DS₂-VASc score** is the validated, guideline-endorsed tool that captures the true stroke risk in AF patients. It incorporates both structural/functional factors (heart failure, hypertension, diabetes, prior stroke/TIA) and demographic factors (age, sex, vascular disease), not the AF pattern itself. ### CHA₂DS₂-VASc Scoring System | Component | Points | |-----------|--------| | **C** — Congestive heart failure / LV dysfunction | 1 | | **H** — Hypertension | 1 | | **A₂** — Age ≥75 years | 2 | | **D** — Diabetes | 1 | | **S₂** — Prior Stroke/TIA/thromboembolism | 2 | | **V** — Vascular disease (MI, PAD, aortic plaque) | 1 | | **A** — Age 65–74 years | 1 | | **Sc** — Sex category (female) | 1 | | **Maximum Score** | **9** | ### Anticoagulation Strategy by Score | CHA₂DS₂-VASc Score | Recommendation | |-------------------|----------------| | 0 (males) / 1 (females) | No anticoagulation | | ≥1 (males) / ≥2 (females) | Anticoagulation (OAC or DOAC) | | High score (≥4) | Intensive anticoagulation; consider additional measures | **High-Yield:** The **prior stroke/TIA (2 points)** and **age ≥75 (2 points)** are the highest-weighted items. A patient with prior stroke + hypertension + diabetes will have a much higher score than a young patient with lone AF, regardless of whether the AF is paroxysmal or persistent. ### Clinical Pearl **Clinical Pearl:** Paroxysmal AF does NOT confer lower stroke risk than persistent AF. Both forms carry equivalent thromboembolic risk if the CHA₂DS₂-VASc score is the same. The distinction between paroxysmal and persistent AF is irrelevant to anticoagulation decisions. ### Application to the Two Patients **Patient 1 (62-year-old woman):** - Hypertension: 1 point - Diabetes: 1 point - Prior stroke: 2 points - Age 55–74: 1 point - Female: 1 point - **Total: 6 points** → Definite anticoagulation **Patient 2 (55-year-old man):** - No comorbidities: 0 points - Age <65: 0 points - Male: 0 points - **Total: 0 points** → No anticoagulation (unless other factors present) [cite:Harrison 21e Ch 233; ESC AF Guidelines 2019]