The TIMI risk score for unstable angina and NSTEMI condenses seven simple yes/no findings into a single number that predicts short-term cardiac events and helps decide whether a patient benefits from an early invasive strategy.
How it works
One point is added for each of the seven criteria that is present, giving a total from 0 to 7:
- Age 65 years or over.
- At least three coronary risk factors (hypertension, diabetes, smoking, hyperlipidaemia, family history).
- Known coronary stenosis of 50% or more.
- ST-segment deviation of 0.5 mm or more on the presenting ECG.
- At least two anginal episodes in the last 24 hours.
- Aspirin use in the prior 7 days.
- Elevated cardiac markers (troponin or CK-MB).
The total maps to the 14-day risk of all-cause death, new or recurrent myocardial infarction, or severe recurrent ischaemia requiring urgent revascularisation:
0-1 -> ~4.7% 2 -> ~8.3% 3 -> ~13.2%
4 -> ~19.9% 5 -> ~26.2% 6-7 -> ~40.9%Worked example
A 68-year-old (1 point for age) with diabetes, hypertension, and a smoking history (1 point, three risk factors), known 60% left anterior descending stenosis on a prior catheterisation (1 point), a positive troponin on arrival (1 point), but with a normal ECG and only one anginal episode in the last 24 hours — scores 4 points. The 14-day event rate for this band is approximately 20%, which places the patient in the intermediate-to-high risk group that typically benefits from early invasive strategy rather than initial conservative management.
A 55-year-old with one risk factor, normal ECG, no prior stenosis, a single anginal episode, and a negative troponin who happens to be on aspirin scores 1 point — roughly 5% 14-day event rate, where conservative management is reasonable while serial markers are pending.
Why aspirin use adds a point — the counter-intuitive criterion
Aspirin use in the prior 7 days seems paradoxical as a risk factor, but it is a marker rather than a cause. A patient whose chest pain developed despite antiplatelet protection has more aggressive, platelet-rich thrombus that aspirin alone is insufficient to suppress. The criterion was validated in the original TIMI 11B and ESSENCE trials and has been confirmed repeatedly: aspirin use identifies a sicker phenotype, not an aspirin failure.
TIMI score limitations and context
The score was derived and validated in specific trial populations from the late 1990s. Real-world patients who are elderly, female, or have significant comorbidities may be less well calibrated. The GRACE score, which incorporates heart rate, blood pressure, and renal function, tends to discriminate better in community populations and contemporary practice. Use TIMI as one input among several — alongside the ECG, serial troponins, local protocol, and clinical judgement — rather than as a standalone decision rule.
The score applies only to UA/NSTEMI presentations. Do not use it for STEMI (where urgent reperfusion is the priority regardless of score) or for undifferentiated chest pain without a working diagnosis of ACS.
This tool is for educational and clinical reference. All management decisions must be made by qualified clinicians with full access to the patient’s history, examination, and investigations.