TIMI Risk Score NSTEMI Calculator

TIMI Risk Score NSTEMI Calculator for Cardiology. In the derivation cohort the 14-day rate of death, MI, or urgent revascularization rose stepwise with score: about 4.7% at 0-1, 8.3% at 2, 13.2% at 3, 19.9% at 4, 26.2% at 5, and 40.9% at 6-7. Scores of 0-2 are commonly treated as low risk, 3-4 as intermediate, and 5-7 as high risk. The score's central clinical value is not just prognostic: higher scores identified a steeper gradient of benefit from enoxaparin, GP IIb/IIIa inhibitors, and an early invasive strategy, so a high score should push toward early angiography and intensified antithrombotic therapy rather than a conservative pathway.

How this calculator works

The TIMI risk score for unstable angina/NSTEMI sums seven equally weighted clinical variables, each scored as present (1) or absent (0), for a total of 0 to 7. The components are age 65 years or older, at least three coronary risk factors, known coronary stenosis of 50% or more, ST-segment deviation of at least 0.5 mm on the presenting ECG, at least two anginal episodes in the prior 24 hours, aspirin use within the preceding 7 days, and elevated cardiac biomarkers (troponin or CK-MB). Rather than a regression-weighted equation, it is a deliberately simple arithmetic count derived from multivariate logistic regression in which each predictor carried comparable prognostic weight, so the summed count estimates 14-day risk of the composite of all-cause death, new or recurrent MI, or severe recurrent ischemia requiring urgent revascularization.

When to use this calculator

Use it at first presentation in adults with unstable angina or NSTEMI (ischemic chest discomfort without persistent ST elevation) to stratify early risk and inform whether an early invasive strategy and more intensive antithrombotic therapy are warranted. It is best applied at the bedside before catheterization, since every input comes from the routine history, ECG, and initial troponin. It should NOT be used in STEMI (a separate TIMI STEMI score exists), in non-cardiac chest pain, or as a rule-out tool in undifferentiated ED chest pain, where HEART or the ED-derived scores perform better; a low TIMI score does not license discharge of a patient with a positive troponin.

Inputs used

  • Age 65 years or older
  • At least three coronary artery disease risk factors
  • Known coronary stenosis
  • Recent aspirin use
  • Severe recent angina
  • ST-segment deviation
  • Positive cardiac biomarkers

Clinical interpretation

In the derivation cohort the 14-day rate of death, MI, or urgent revascularization rose stepwise with score: about 4.7% at 0-1, 8.3% at 2, 13.2% at 3, 19.9% at 4, 26.2% at 5, and 40.9% at 6-7. Scores of 0-2 are commonly treated as low risk, 3-4 as intermediate, and 5-7 as high risk. The score's central clinical value is not just prognostic: higher scores identified a steeper gradient of benefit from enoxaparin, GP IIb/IIIa inhibitors, and an early invasive strategy, so a high score should push toward early angiography and intensified antithrombotic therapy rather than a conservative pathway.

Worked example

A 70-year-old with hypertension, diabetes, and a smoking history (3+ risk factors) presents with two episodes of rest angina overnight. ECG shows 1 mm inferolateral ST depression and the initial troponin is elevated. He was not taking aspirin. Score: age 65+ (1) + 3 risk factors (1) + ST deviation (1) + 2 anginal events (1) + positive biomarker (1) = 5 of 7; no prior documented stenosis and no recent aspirin. A score of 5 corresponds to roughly a 26% rate of the 14-day composite endpoint in the original TIMI 11B cohort, placing him in the high-risk band that derives the greatest benefit from an early invasive approach and GP IIb/IIIa or LMWH therapy.

Limitations and safety notes

The score was derived from clinical-trial populations that under-represented women, older adults, and patients with renal impairment, and its C-statistic (~0.65) reflects only modest discrimination. Because all seven items are weighted equally, it under-weights the powerful independent prognostic effect of troponin magnitude and of hemodynamic or renal status, so GRACE typically outperforms it for predicting in-hospital and 6-month mortality and is preferred by ESC guidance. The "3+ risk factors" and "prior 50% stenosis" items depend on history that may be unavailable or unreliable at presentation, and a reassuringly low score in a biomarker-positive patient must not override clinical judgment.

Frequently asked questions

How is the TIMI NSTEMI score different from the GRACE score?

TIMI is a fast 0-7 bedside count of seven equally weighted items predicting a 14-day composite (death, MI, or urgent revascularization). GRACE uses weighted continuous variables (age, heart rate, blood pressure, creatinine, Killip class, cardiac arrest, ST deviation, biomarkers) and predicts in-hospital and 6-month mortality with better discrimination. Many centers use TIMI for speed and GRACE, which ESC guidelines favor, for mortality estimation.

What counts as ST-segment deviation for the score?

Transient or persistent ST-segment depression (or transient elevation) of at least 0.5 mm (0.05 mV) on the presenting ECG. Isolated T-wave inversion does not qualify for this item, though it may still be an ischemic finding.

Does a low TIMI score mean I can safely discharge the patient?

No. The score was built to guide inpatient management intensity in confirmed UA/NSTEMI, not to rule out ACS in the ED. A patient with a positive troponin has NSTEMI by definition regardless of a low score. For ED rule-out of undifferentiated chest pain, HEART or an accelerated troponin pathway is more appropriate.

Which risk factors count toward the '3 or more risk factors' item?

The conventional coronary artery disease risk factors: family history of premature CAD, hypertension, hypercholesterolemia, diabetes, and current smoking. At least three of these being present scores the point.

How does the score change treatment decisions?

Higher scores identified patients who gained the most from enoxaparin, glycoprotein IIb/IIIa inhibitors, and an early invasive strategy in the original trials. In practice a high score (5-7) supports early angiography and intensified antithrombotic therapy, while a very low score supports a more conservative, medically managed pathway.

References

  • Antman EM, Cohen M, Bernink PJ, McCabe CH, Horacek T, Papuchis G, Mautner B, Corbalan R, Radley D, Braunwald E. The TIMI risk score for unstable angina/non-ST elevation MI: A method for prognostication and therapeutic decision making. JAMA. 2000. PMID: 10938172.
  • Sabatine MS, Antman EM. The Thrombolysis in Myocardial Infarction risk score in unstable angina/non-ST-segment elevation myocardial infarction. J Am Coll Cardiol. 2003. PMID: 12644346.
  • European Society of Cardiology (Byrne RA, et al., ESC Scientific Document Group). 2023 ESC Guidelines for the management of acute coronary syndromes. 2023.

Editorial review and citation methodology

Reviewed by the Quick Medical Calculator Editorial Team. Last reviewed: April 3, 2026. The review checks calculator inputs, intended population, interpretation, limitations, and source alignment.

  • Prefer original validation studies for scoring systems and prediction tools.
  • Use current specialty society guidance, transplant allocation policy, public health guidance, or regulator resources when they govern clinical use.
  • Include limitations and safety notes when a calculator is population-specific, context-dependent, or unsuitable as a standalone decision tool.

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