Calculate the TIMI risk score for unstable angina and NSTEMI. Predicts 14-day risk of death, MI, or urgent revascularization using 7 clinical variables.
The TIMI Risk Score for UA/NSTEMI is a widely used clinical prediction tool developed by Antman et al. (2000) from the TIMI-11B trial data. It predicts the 14-day likelihood of death, new or recurrent myocardial infarction, or need for urgent revascularization in patients presenting with unstable angina (UA) or non-ST-elevation myocardial infarction (NSTEMI).
The score uses 7 binary variables (each contributing 1 point): age ≥65, ≥3 coronary artery disease risk factors, known coronary stenosis ≥50%, aspirin use in the past 7 days, ≥2 anginal episodes in 24 hours, ST deviation ≥0.5 mm on ECG, and elevated cardiac biomarkers. The simplicity of the 7-point binary scoring makes it one of the easiest clinical risk scores to calculate at the bedside.
The TIMI UA/NSTEMI score directly guides management strategy: low scores (0-2) support an ischemia-guided (conservative) approach with non-invasive testing, while higher scores (≥3) support an early invasive strategy with cardiac catheterization within 24-72 hours, as recommended by ACC/AHA guidelines.
Management of UA/NSTEMI involves a critical decision: early invasive strategy (cardiac catheterization within 24-72 hours) versus ischemia-guided strategy (medical management with selective catheterization). Multiple trials (TACTICS-TIMI 18, FRISC-II, RITA-3) demonstrated that patients with higher TIMI scores benefit significantly more from early invasive strategy.
At the bedside, the TIMI score takes seconds to calculate and immediately classifies the patient into a management pathway, reducing variability in care and ensuring appropriate resource utilization.
TIMI UA/NSTEMI Score (7 binary variables, 0-7): Age ≥65: 1 pt ≥3 CAD risk factors (HTN, DM, FHx, smoking, dyslipidemia): 1 pt Known CAD (≥50% stenosis): 1 pt Aspirin use in past 7 days: 1 pt ≥2 anginal episodes in past 24h: 1 pt ST deviation ≥0.5 mm: 1 pt Elevated cardiac biomarkers: 1 pt 14-day MACE: 0-1 (~5%), 2 (~8%), 3 (~13%), 4 (~20%), 5 (~26%), 6-7 (~41%)
Result: TIMI 7/7 — 14-Day MACE ~41%, Very High Risk
All 7 criteria present: age ≥65, ≥3 risk factors, known CAD, aspirin use, frequent angina, ST changes, and elevated troponin. This patient has the highest possible TIMI score with ~41% risk of death, MI, or urgent revascularization within 14 days. Immediate cardiac catheterization (within 2 hours), aggressive dual antiplatelet therapy, and ICU monitoring are indicated.
The TACTICS-TIMI 18 trial demonstrated that patients with TIMI ≥3 had significantly reduced death/MI/rehospitalization at 6 months with early invasive strategy (14.3% vs 24.3%, p<0.001), while TIMI 0-2 patients showed no significant benefit from early invasive approach. This trial established the TIMI score as the primary tool for guiding the invasive vs. conservative decision.
The HEART score (History, ECG, Age, Risk factors, Troponin) was developed specifically for undifferentiated chest pain in the ED. While TIMI was designed for confirmed ACS patients, HEART is optimized for the earlier decision: "Does this patient have ACS?" The two scores are complementary — HEART for diagnosis, TIMI for management once ACS is confirmed.
Higher TIMI scores identify patients who benefit most from potent dual antiplatelet therapy (DAPT). TIMI ≥3 patients should receive loading doses of aspirin + P2Y12 inhibitor (clopidogrel, ticagrelor, or prasugrel) early, with the choice of agent guided by invasive strategy timing and bleeding risk (HAS-BLED, CRUSADE scores).
The paradox is explained by selection: aspirin use in the 7 days before presentation means the ACS occurred DESPITE aspirin therapy ("breakthrough" event). This indicates aspirin-resistant thrombosis or more aggressive plaque pathology, which statistically predicts worse outcomes. It does not mean aspirin is harmful.
The original TIMI trial used 5 traditional risk factors: (1) Family history of premature CAD (male first-degree relative <55, female <65), (2) Hypertension, (3) Diabetes mellitus, (4) Current smoking, (5) Hyperlipidemia. Having ≥3 of these 5 earns 1 point.
GRACE uses 8 variables (some continuous, requiring a calculator) and predicts both in-hospital and 6-month mortality. It is considered more discriminant than TIMI in many studies. However, TIMI is simpler (binary scoring, mental calculation) and specifically guides the invasive vs. conservative decision. ACC/AHA guidelines endorse both.
Any elevated cardiac biomarker counts: high-sensitivity troponin I or T (most common), conventional troponin, or CK-MB. High-sensitivity troponin has made the biomarker criterion more sensitive — many patients previously classified as UA are now reclassified as NSTEMI with hs-troponin assays.
ACC/AHA guidelines recommend an early invasive strategy for TIMI ≥3, but this is not absolute. Patient factors like advanced comorbidities, prior revascularization decisions, infection, or patient preference may favor a conservative approach. The score provides evidence to support the invasive strategy discussion, not mandate it.
No. The TIMI UA/NSTEMI score is validated only for non-ST-elevation ACS. STEMI has its own TIMI score (TIMI STEMI Score) with different variables. Using the wrong score for the wrong presentation will give inaccurate risk estimates.