TIMI score calculator for unstable angina and NSTEMI
Score a patient with unstable angina or non-ST elevation myocardial infarction (UA/NSTEMI) on the seven TIMI risk score predictors, 1 point each, and see the 14-day rate of death, new or recurrent MI, or severe recurrent ischemia needing urgent revascularization for that score in the original 2000 study.
Guides
- TIMI score for NSTEMI vs STEMI: two different scoresThe TIMI score for UA/NSTEMI and the TIMI score for STEMI are separate scores. Compare their items, points, outcomes and risk tables, with a worked example.
How this TIMI score calculator works
This TIMI score calculator uses the TIMI risk score for unstable angina and non-ST elevation myocardial infarction, published by Antman and colleagues in JAMA in August 2000. The authors derived it from the 1957 patients with UA/NSTEMI assigned unfractionated heparin in the TIMI 11B trial, choosing seven independent prognostic variables by multivariate logistic regression. Each variable is given a value of 1 when present and 0 when absent, and the score is the simple sum of the variables present, so it runs from 0 to 7. The goal was a score with broad applicability that is easily calculated at presentation, needs no computer, and identifies patients who respond differently to treatment. The outcome is at least one of all-cause death, new or recurrent myocardial infarction, or severe recurrent ischemia requiring urgent revascularization through 14 days after randomization. Three cohorts validated it: the enoxaparin arm of TIMI 11B and both arms of the ESSENCE trial.
| Predictor | Scores 1 point when |
|---|---|
| Age | 65 years or older |
| Coronary risk factors | At least 3 of: family history of coronary artery disease, hypertension, hypercholesterolemia, diabetes, current smoker |
| Known coronary stenosis | A prior cardiac catheterization showed at least 1 coronary stenosis of 50% or more |
| ST deviation | ST-segment deviation on the electrocardiogram at presentation |
| Severe anginal symptoms | At least 2 anginal events in the prior 24 hours |
| Aspirin | Use of aspirin in the prior 7 days |
| Cardiac markers | Elevated serum cardiac markers: creatine kinase MB fraction and/or cardiac-specific troponin |
TIMI risk score = number of the 7 predictors present, 1 point each (0 to 7)
Every predictor is yes or no. A patient who has never had a cardiac catheterization, or whose catheterization showed no stenosis of 50% or more, scores 0 for known stenosis. Cardiac markers count only as raised or not raised, with no extra weight for how high they are. The trial patients presented within 24 hours of an episode of UA/NSTEMI at rest, and in TIMI 11B an ECG qualified for enrollment with transient ST elevation or persistent ST depression of 0.05 mV or more. Patients with planned revascularization within 24 hours, a correctable cause of angina or a contraindication to anticoagulation were excluded. The authors assigned equal weights on purpose: adding weights or more variables could raise the c statistic, but would cost the simplicity that lets the score be added up at the bedside.
TIMI score interpretation: 14-day risk by score
TIMI score interpretation rests on one result: the share of patients at each score who had a primary end point event within 14 days in the TIMI 11B test cohort. Event rates rose steadily with the score, from 4.7% at 0 or 1 to 8.3% at 2, 13.2% at 3, 19.9% at 4, 26.2% at 5 and 40.9% at 6 or 7 (P<.001 for trend), and the same rising pattern held in all three validation cohorts. Scores of 0 and 1, and of 6 and 7, were pooled because few patients had extreme scores. All-cause death alone rose from 0% at 0 or 1 to 10.6% at 6 or 7. The paper does not name low, intermediate or high groups, so this calculator reports the rate for the exact score rather than a label. Discrimination was modest: the c statistic for the composite end point was 0.65 in the test cohort and 0.59 to 0.65 in the validation cohorts.
| TIMI score | Death, MI or urgent revascularization | All-cause death | Myocardial infarction | Urgent revascularization | Death or nonfatal MI |
|---|---|---|---|---|---|
| 0–1 | 4.7% | 0% | 3.5% | 1.2% | 3.5% |
| 2 | 8.3% | 0.9% | 1.8% | 6.2% | 2.4% |
| 3 | 13.2% | 1.8% | 4.0% | 9.1% | 4.8% |
| 4 | 19.9% | 2.6% | 5.9% | 14.0% | 7.5% |
| 5 | 26.2% | 7.1% | 9.7% | 15.0% | 13.5% |
| 6–7 | 40.9% | 10.6% | 16.7% | 27.3% | 22.7% |
The component rates come from Table 2 of the paper, for the same 1957 patients. Urgent revascularization drives most of the rise at middle scores, while death and myocardial infarction climb most steeply at 5 and above. For single outcomes across the whole TIMI 11B population, the c statistic was 0.74 for all-cause mortality, 0.66 for myocardial infarction, 0.68 for urgent revascularization and 0.63 for death or myocardial infarction. A worked example: a 70-year-old with ST depression on the presenting ECG and a raised troponin, who took aspirin this week, has fewer than 3 coronary risk factors, no known coronary stenosis and one episode of angina in the past 24 hours, scores 4 points (age, ST deviation, aspirin and markers), with a 14-day event rate of 19.9%.
When the TIMI risk score is less accurate
The TIMI risk score is less accurate outside the patients it was built on, and Antman and colleagues set out the limits themselves. It was developed in patients who qualified for two phase 3 trials run between 1994 and 1998, so its performance in emergency departments and office settings had not been tested, and the paper warns that the numbers linking score to risk may change when the score is applied to other populations. Cardiac markers count only as present or absent, with no weight for how high they are, and other markers such as C-reactive protein were left out. The score is designed for prognosis at the time of first presentation and uses nothing learned later in hospital. It also does not apply to ST-elevation MI, which has its own TIMI score. In emergency patients with undifferentiated chest pain, Backus and colleagues found a c statistic for 6-week events of 0.75 for TIMI against 0.83 for the HEART score.
For undifferentiated chest pain in the emergency department, use the HEART score calculator; for how the scores compared head to head, see HEART vs TIMI vs GRACE.
Questions
What does a TIMI score of 3 mean?
In the TIMI 11B test cohort, 13.2% of patients with a score of 3 died, had a new or recurrent myocardial infarction, or needed urgent revascularization for severe recurrent ischemia within 14 days. All-cause death alone was 1.8%.
What is a high TIMI score?
The 2000 paper does not define low, intermediate or high groups. It reports the event rate for each score, and the rate rose from 4.7% at 0 or 1 to 26.2% at 5 and 40.9% at 6 or 7.
Can I use this TIMI score for STEMI?
No. ST-elevation MI has a separate TIMI risk score from Morrow and colleagues (Circulation, 2000), with weighted items, a 0 to 14 range and 30-day mortality as its outcome. The guide to the TIMI score for NSTEMI vs STEMI sets out both.
Why does aspirin use add a point?
Use of aspirin in the prior 7 days was one of the seven independent predictors of 14-day events in the TIMI 11B test cohort, so the score counts it like any other predictor. It describes risk and is not advice about any medicine.
Is my data sent anywhere?
No. The calculation runs in your browser, and the boxes you tick are not sent or stored.
Sources
- Antman EM, Cohen M, Bernink PJLM, et al. The TIMI risk score for unstable angina/non-ST elevation MI: a method for prognostication and therapeutic decision making. JAMA. 2000;284(7):835–842. doi:10.1001/jama.284.7.835
- Morrow DA, Antman EM, Charlesworth A, et al. TIMI risk score for ST-elevation myocardial infarction: a convenient, bedside, clinical score for risk assessment at presentation. Circulation. 2000;102(17):2031–2037. doi:10.1161/01.CIR.102.17.2031
- Backus BE, Six AJ, Kelder JC, et al. A prospective validation of the HEART score for chest pain patients at the emergency department. Int J Cardiol. 2013;168(3):2153–2158. doi:10.1016/j.ijcard.2013.01.255