TIMI Risk Score Calculator
Risk stratification for acute coronary syndrome (ACS). Calculate TIMI scores for both STEMI and NSTEMI/Unstable Angina to guide treatment decisions.
Select TIMI Score Type
TIMI Score for STEMI
About TIMI Scores
TIMI for STEMI
Developed from the InTIME II trial (n=15,078), the TIMI STEMI score predicts 30-day mortality using 8 variables worth up to 14 points total.
TIMI for NSTEMI/UA
Derived from TIMI 11B and ESSENCE trials (n=7,081), this 7-point score predicts 14-day risk of death, MI, or urgent revascularisation.
Risk Interpretation
TIMI STEMI - 30-Day Mortality
| Score | Mortality |
|---|---|
| 0 | 0.8% |
| 1 | 1.6% |
| 2 | 2.2% |
| 3 | 4.4% |
| 4 | 7.3% |
| 5 | 12.4% |
| 6 | 16.1% |
| 7 | 23.4% |
| 8+ | >26% |
TIMI Score Components Explained
TIMI STEMI Components
| Variable | Points |
|---|---|
| Age 65-74 years | 2 |
| Age ≥75 years | 3 |
| Diabetes, hypertension, or angina | 1 |
| Systolic BP <100 mmHg | 3 |
| Heart rate >100 bpm | 2 |
| Killip class II-IV | 2 |
| Weight <67 kg | 1 |
| Anterior STEMI or LBBB | 1 |
| Time to treatment >4 hours | 1 |
| Maximum Score | 14 |
TIMI NSTEMI/UA Components
| Variable | Points |
|---|---|
| Age ≥65 years | 1 |
| ≥3 CAD risk factors | 1 |
| Known CAD (≥50% stenosis) | 1 |
| Aspirin use in last 7 days | 1 |
| Severe angina (≥2 episodes/24h) | 1 |
| ST deviation ≥0.5mm | 1 |
| Elevated cardiac markers | 1 |
| Maximum Score | 7 |
Clinical Application
STEMI Management
For STEMI patients, the TIMI score helps:
- Predict prognosis after reperfusion
- Identify candidates for aggressive monitoring
- Guide discussions with patients and families
- Inform transfer decisions to tertiary centres
Primary PCI remains the treatment of choice regardless of TIMI score when available within guideline timeframes.
NSTEMI Strategy
TIMI NSTEMI/UA guides invasive strategy timing:
- Score 0-2 (Low): Conservative or delayed invasive approach
- Score 3-4 (Intermediate): Early invasive approach (<72h)
- Score 5-7 (High): Urgent invasive approach (<24h)
Use alongside GRACE score and clinical judgement per ESC/NICE guidelines.
Medical Therapy
Higher TIMI scores support more aggressive pharmacotherapy:
- Potent P2Y12 inhibitors (prasugrel, ticagrelor)
- Glycoprotein IIb/IIIa inhibitors
- Low molecular weight heparin
- Intensive statin therapy
Always balance bleeding risk against ischaemic benefit.
Frequently Asked Questions
The two scores are distinct tools developed for different patient populations:
- TIMI STEMI: Uses 8 variables (max 14 points) to predict 30-day mortality in patients with confirmed ST-elevation MI. Factors include haemodynamic parameters (BP, HR, Killip class) and ECG location.
- TIMI NSTEMI/UA: Uses 7 binary variables (max 7 points) to predict 14-day composite outcome (death, MI, urgent revascularisation) in patients with NSTEMI or unstable angina. Focuses on risk factors and presentation features.
Choose the appropriate score based on the patient's ECG diagnosis at presentation.
Both are validated ACS risk scores, but they differ in several ways:
- GRACE: More complex (8 variables including renal function and cardiac arrest), predicts in-hospital and 6-month mortality, applies to all ACS types. Generally considered more accurate but requires more data.
- TIMI: Simpler to calculate at bedside, separate scores for STEMI and NSTEMI, shorter prediction timeframes. Easier to use but may be slightly less discriminatory.
UK and European guidelines (NICE, ESC) recommend GRACE for risk stratification in NSTEMI, while TIMI remains widely used clinically, particularly in emergency settings where rapid assessment is needed.
This may seem counterintuitive, but aspirin use in the 7 days prior to presentation is a marker of:
- Known or suspected cardiovascular disease requiring secondary prevention
- Aspirin failure - the patient developed an acute event despite antiplatelet therapy
- More advanced atherosclerotic disease
It does NOT mean aspirin is harmful - aspirin should still be given to all ACS patients without contraindications. The variable identifies patients with established disease who have a higher baseline risk.
Killip classification assesses clinical signs of heart failure in MI patients:
- Killip I: No clinical signs of heart failure (0 points in TIMI)
- Killip II: Rales/crackles, S3 gallop, elevated JVP (2 points in TIMI)
- Killip III: Frank pulmonary oedema (2 points in TIMI)
- Killip IV: Cardiogenic shock - hypotension, oliguria, cyanosis (2 points in TIMI)
In the TIMI STEMI score, Killip class II-IV all receive 2 points, reflecting the prognostic importance of any degree of heart failure.
Yes, particularly the TIMI STEMI score, which uses readily available clinical data:
- Age (from patient/records)
- Medical history (patient/family report)
- Vital signs (BP, HR - standard monitoring)
- Killip class (clinical examination)
- Weight (estimated if needed)
- ECG findings (prehospital ECG)
Prehospital TIMI scoring can help paramedics communicate risk to receiving hospitals and support bypass decisions for direct transfer to PCI centres.
Limitations
Important Considerations
- TIMI scores were derived from clinical trial populations and may not fully generalise to all real-world patients
- The STEMI score was developed in the thrombolytic era; outcomes may differ with primary PCI
- Scores provide population-level risk estimates - individual patient outcomes may vary
- Do not use TIMI scores to withhold appropriate treatment from any patient
- Consider using alongside other tools (GRACE, CRUSADE bleeding score) for comprehensive assessment
- Clinical judgement should always take precedence over calculated scores
Disclaimer
This calculator is provided for educational and informational purposes only. It is not intended to be a substitute for professional medical advice, diagnosis, or treatment.
- Always seek the advice of a qualified healthcare provider with any questions regarding a medical condition.
- Never disregard professional medical advice or delay seeking it because of information from this tool.
- Clinical decision-making should always incorporate the full clinical context, patient preferences, and local protocols.
- The creators of this tool accept no liability for decisions made based on its output.
If you are a patient: please discuss any results with your healthcare provider. This tool is designed for use by medical professionals and may not be appropriate for self-assessment.
References
- Morrow DA, et al. TIMI Risk Score for ST-Elevation Myocardial Infarction: A Convenient, Bedside, Clinical Score for Risk Assessment at Presentation. Circulation. 2000;102:2031-2037. doi:10.1161/01.CIR.102.17.2031
- Antman EM, et al. The TIMI Risk Score for Unstable Angina/Non-ST Elevation MI. JAMA. 2000;284(7):835-842. doi:10.1001/jama.284.7.835
- Collet JP, et al. 2020 ESC Guidelines for the management of acute coronary syndromes in patients presenting without persistent ST-segment elevation. Eur Heart J. 2021;42(14):1289-1367.
- Ibanez B, et al. 2017 ESC Guidelines for the management of acute myocardial infarction in patients presenting with ST-segment elevation. Eur Heart J. 2018;39(2):119-177.
- NICE. Acute coronary syndromes (NG185). 2020. https://www.nice.org.uk/guidance/ng185