Why use it

Rapid bedside ACS risk stratification. Guides early invasive vs. conservative strategy decisions. Validated in multiple large trials (TACTICS-TIMI 18, PRISM-PLUS). Widely recommended by ACC/AHA guidelines.

About

The TIMI Risk Score for UA/NSTEMI predicts the risk of death, new or recurrent MI, or need for urgent revascularization within 14 days. It uses seven variables scored 0-1 each, producing a simple bedside risk estimate that guides the intensity of anti-ischemic therapy and invasive strategy timing.

When to use

Patients presenting with unstable angina or NSTEMI
Decision on timing of invasive strategy (early vs. delayed)
Risk communication with patients and families

Formula

One point each (total 0-7): 1. Age ≥ 65 2. ≥ 3 CAD risk factors (FHx, HTN, DM, hyperlipidemia, smoking) 3. Known CAD (≥ 50% stenosis) 4. ASA use in past 7 days 5. ≥ 2 anginal episodes in 24h 6. ST deviation ≥ 0.5mm 7. Elevated cardiac biomarkers

Pearls & pitfalls

TIMI is for NSTEMI/UA only — do not use for STEMI (use TIMI STEMI score separately).
Each 1-point increase correlates with ~5% increase in 14-day event rate.
Score ≥ 3 generally favors early invasive approach (catheterization within 24-72h).
Troponin elevation alone (even marginally) scores +1.
Aspirin use within 7 days reflects refractoriness to aspirin therapy, not just chronic use.
GRACE score is an alternative with greater discriminatory power but more complex to calculate.

Next steps

Score 0-2: Low risk (~4-8% event rate), consider conservative strategy. Score 3-4: Intermediate risk (~13-20%), early invasive strategy benefits. Score 5-7: High risk (~26-41%), urgent invasive strategy strongly recommended.

Evidence

Derived from TIMI 11B trial (Antman et al., JAMA 2000). Validated in PRISM-PLUS, TACTICS-TIMI 18, and ESSENCE trials. ACC/AHA Class I recommendation for risk stratification in NSTE-ACS.

References

Antman EM et al. The TIMI risk score for unstable angina/non-ST elevation MI. JAMA. 2000;284(7):835-842. — link

TIMI Score (NSTEMI/UA)

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