Chadsvasc Calculator — Score, Risk Class & Clinical Signals
Quick start: this tool scores stroke risk in non‑valvular atrial fibrillation. Enter Age (years), Sex, and check clinical history items. You get a total score and a risk class prompt.
What the score tells you and when OAC is considered
The CHA2DS2‑VASc total estimates ischemic stroke risk per AF episode history. Lower totals suggest observation; higher totals usually prompt oral anticoagulation (OAC) unless contraindicated.
- Low risk: Male 0 or Female 1 — often no anticoagulation.
- Intermediate: Male 1 — consider OAC based on net benefit and preference.
- High risk: ≥2 (or Female ≥2) — OAC generally recommended barring bleeding risks.
Note: This tool assists risk quantification; it does not replace clinician judgment.
How the score is built step‑by‑step (inputs → outputs)
- Enter Age (years). If unknown, you may toggle “Use age 65–74.”
- Select Sex (Male or Female).
- Tick history: Congestive heart failure / LV dysfunction, Hypertension, Diabetes mellitus, Prior stroke/TIA/thromboembolism, Vascular disease.
- Calculator sums weighted points and displays the total and risk class cue.
Formula components and point weights at a glance
Scoring components (points in parentheses):
- Congestive heart failure / LV dysfunction (1)
- Hypertension (1)
- Age ≥75 years (2) — else Age 65–74 years (1)
- Diabetes mellitus (1)
- Prior stroke/TIA/thromboembolism (2)
- Vascular disease (1)
- Female sex (1)
Compact method: total = CHF(1) + HTN(1) + DM(1) + Stroke/TIA(2) + Vascular(1) + Age ≥75(2) or 65–74(1) + Female(1). Exact age overrides the 65–74 toggle.
Worked example with realistic inputs and rounding
Example A
Inputs: Age 78 years; Sex Female; CHF yes; Hypertension yes; Diabetes no; Prior stroke/TIA no; Vascular disease yes; “Use age 65–74” off.
Points: Age ≥75 = 2; Female = 1; CHF = 1; HTN = 1; Vascular = 1; Stroke/TIA = 0; DM = 0.
Total score = 2 + 1 + 1 + 1 + 1 = 6. High risk: OAC typically recommended if bleeding risk acceptable.
Example B (age unknown, using the toggle)
Inputs: Age not entered; Sex Male; No CHF/HTN/DM/Stroke/Vascular; “Use age 65–74” on.
Points: Age 65–74 = 1; others = 0; Male sex = 0.
Total score = 1. Intermediate risk for a male; consider OAC based on net clinical benefit.
Scenario comparison: small changes that shift treatment
- Change only Prior stroke/TIA from “no” to “yes”: add 2 points. This single change often moves a patient from observation to clear OAC indication.
- Age crossing 75: moving from 74 to 75 increases age points from 1 to 2 (+1 total), potentially changing risk class.
Assumptions, limits, and frequent input mistakes
- Age entry: Use whole years; if exact age is provided, ignore the 65–74 toggle.
- Non‑valvular AF: This score applies to non‑valvular cases; other contexts differ.
- Sex points: Female sex adds 1 point; risk interpretation depends on the total.
- Vascular disease: Count prior MI, peripheral arterial disease, or aortic plaque.
- Do not double‑count age bands: use either ≥75 (2) or 65–74 (1), not both.
- Device/data variability: Diagnoses should be clinician‑confirmed, not self‑suspected.
Tips for interpreting the number and planning next steps
- Prior stroke/TIA weighs most (2 points); age ≥75 also weighs 2. These dominate decisions.
- When total is borderline (e.g., Male 1), discuss bleeding risk and preferences.
- Reassess yearly or after new events (MI, TIA) or birthdays crossing 65 or 75.
Semantic variants used: CHA2DS2‑VASc score, stroke risk score for AF, AF stroke calculator, thromboembolism risk score, CHA2DS2‑VASc estimator, atrial fibrillation risk scoring.
Medical note: Use this score as a structured input to shared decision‑making; management must consider bleeding scores, contraindications, and patient values.