TIMI Score Calculator for UA NSTEMI

Calculate 14-day risk of death, myocardial infarction, or urgent revascularization in unstable angina and non-ST elevation myocardial infarction (UA NSTEMI) patients.

The TIMI Score for UA NSTEMI is a validated risk assessment tool that predicts 14-day adverse cardiovascular events in patients with unstable angina or non-ST elevation myocardial infarction.

Examples

Click on any example to load it into the calculator.

Low Risk Patient

low_risk

Young patient with minimal risk factors and no significant cardiac history.

Age ≥65: No

Known CAD: No

Aspirin Use: No

Severe Angina: No

Elevated Biomarkers: No

ST Changes: No

CAD Stenosis ≥50%: No

Moderate Risk Patient

moderate_risk

Elderly patient with some risk factors and known coronary disease.

Age ≥65: Yes

Known CAD: Yes

Aspirin Use: No

Severe Angina: No

Elevated Biomarkers: No

ST Changes: No

CAD Stenosis ≥50%: Yes

High Risk Patient

high_risk

Patient with multiple risk factors including elevated biomarkers and ST changes.

Age ≥65: Yes

Known CAD: Yes

Aspirin Use: Yes

Severe Angina: Yes

Elevated Biomarkers: Yes

ST Changes: Yes

CAD Stenosis ≥50%: Yes

Borderline Case

borderline

Patient with mixed risk factors requiring careful clinical assessment.

Age ≥65: Yes

Known CAD: No

Aspirin Use: No

Severe Angina: Yes

Elevated Biomarkers: Yes

ST Changes: No

CAD Stenosis ≥50%: No

Other Titles
Understanding TIMI Score for UA NSTEMI: A Comprehensive Guide
Learn how to calculate and interpret the TIMI Score for UA NSTEMI, understand its clinical significance, and apply it in acute coronary syndrome management.

What is the TIMI Score for UA NSTEMI?

  • Historical Development and Validation
  • Clinical Significance and Applications
  • Components and Scoring System
The TIMI (Thrombolysis in Myocardial Infarction) Score for UA NSTEMI is a validated risk assessment tool developed to predict 14-day risk of death, myocardial infarction, or urgent revascularization in patients with unstable angina or non-ST elevation myocardial infarction. This scoring system was developed from the TIMI 11B trial and has been extensively validated in multiple clinical trials and real-world populations. The score provides a quantitative assessment of short-term cardiovascular risk that helps guide clinical decision-making regarding treatment intensity and resource allocation.
The Seven Components of the TIMI Score
The TIMI Score for UA NSTEMI incorporates seven key clinical variables that have been shown to independently predict adverse cardiovascular events: age ≥65 years, known coronary artery disease (≥50% stenosis), aspirin use in the last 7 days, severe angina (≥2 episodes in 24 hours), elevated cardiac biomarkers, ST changes ≥0.5mm, and known CAD stenosis ≥50%. Each component is assigned 1 point, with higher scores indicating greater risk of adverse events within 14 days.
Mathematical Formula and Scoring System
The TIMI Score is calculated by summing the points for each risk factor present: Age ≥65 years (1 point), Known CAD ≥50% stenosis (1 point), Aspirin use in last 7 days (1 point), Severe angina ≥2 episodes in 24h (1 point), Elevated cardiac biomarkers (1 point), ST changes ≥0.5mm (1 point), and Known CAD stenosis ≥50% (1 point). The total score ranges from 0 to 7, with higher scores indicating increased 14-day risk of death, MI, or urgent revascularization.
Clinical Validation and Prognostic Value
The TIMI Score for UA NSTEMI has been validated in numerous studies involving thousands of patients. It has demonstrated excellent prognostic value for predicting 14-day adverse events, with event rates ranging from 4.7% for low-risk patients (score 0-1) to 40.9% for very high-risk patients (score 6-7). The score's predictive accuracy is maintained across different age groups, genders, and ethnicities, making it a robust tool for risk assessment in diverse UA NSTEMI populations.

Key Risk Factors Explained:

  • Age ≥65 years indicates increased cardiovascular risk due to age-related changes in coronary arteries and reduced physiological reserve.
  • Known CAD with ≥50% stenosis indicates established coronary disease and higher risk for acute coronary events.
  • Recent aspirin use may indicate ongoing antiplatelet therapy and could affect risk assessment and treatment decisions.

Step-by-Step Guide to Using the TIMI Score Calculator

  • Patient Assessment and Data Collection
  • Score Calculation Process
  • Result Interpretation and Clinical Application
Using the TIMI Score calculator for UA NSTEMI requires systematic collection of clinical data and careful interpretation of results. The process begins with comprehensive patient assessment, including medical history, physical examination, electrocardiographic findings, and laboratory results. Each component of the score must be evaluated based on established criteria to ensure accurate risk stratification.
Data Collection and Assessment
The first step involves collecting all necessary clinical information. Age should be verified from patient records, with patients 65 years or older receiving 1 point. Known coronary artery disease should be documented from previous angiographic studies, with ≥50% stenosis in any coronary artery qualifying for 1 point. Recent medication history should be reviewed to determine aspirin use within the last 7 days.
Angina Assessment and ECG Interpretation
Severe angina is defined as two or more episodes within the last 24 hours, with each episode lasting at least 5 minutes and requiring sublingual nitroglycerin or rest for relief. ECG interpretation should focus on ST segment changes, with depression or transient elevation ≥0.5mm qualifying for 1 point. These changes should be present in at least two contiguous leads and not attributable to other causes.
Biomarker Assessment and Final Calculation
Cardiac biomarkers should be measured using standard laboratory methods, with elevation above the 99th percentile of the upper reference limit qualifying for 1 point. Common biomarkers include troponin I, troponin T, and CK-MB. Once all components are assessed, the total score is calculated by summing all positive findings, with scores ranging from 0 to 7.

Clinical Assessment Tips:

  • Always verify age from official documentation rather than patient self-report.
  • Review previous angiographic reports carefully to confirm CAD stenosis ≥50%.
  • Document the timing and frequency of angina episodes precisely for accurate scoring.

Real-World Applications of TIMI Score in Clinical Practice

  • Emergency Department Triage
  • Treatment Strategy Selection
  • Resource Allocation and Follow-up Planning
The TIMI Score for UA NSTEMI has become an essential tool in modern cardiovascular medicine, with applications spanning from emergency department triage to long-term treatment planning. Its ability to rapidly stratify risk makes it invaluable for guiding immediate clinical decisions and optimizing patient outcomes through evidence-based management strategies.
Emergency Department and Acute Care
In emergency departments, the TIMI Score helps determine the urgency of cardiac catheterization and the need for intensive monitoring. Low-risk patients (score 0-1) may be managed conservatively with medical therapy and outpatient follow-up, while high-risk patients (score 5-7) require immediate invasive evaluation and intensive care. This stratification optimizes resource utilization and reduces unnecessary hospitalizations while ensuring high-risk patients receive timely intervention.
Treatment Strategy and Medication Selection
The TIMI Score guides selection of antiplatelet and anticoagulant therapies. High-risk patients benefit from more aggressive antiplatelet therapy, including dual antiplatelet therapy with aspirin and P2Y12 inhibitors, as well as consideration of glycoprotein IIb/IIIa inhibitors during percutaneous coronary intervention. Low-risk patients may be managed with aspirin alone or less intensive antiplatelet regimens.
Long-term Management and Follow-up
Risk stratification using the TIMI Score also informs long-term management strategies. High-risk patients require more frequent follow-up, aggressive risk factor modification, and consideration of secondary prevention strategies. The score helps identify patients who may benefit from cardiac rehabilitation programs and intensive lifestyle modification interventions.

Clinical Decision Points:

  • TIMI Score 0-1: Consider outpatient management with early follow-up.
  • TIMI Score 2-4: Inpatient observation with consideration of early invasive strategy.
  • TIMI Score 5-7: Immediate invasive evaluation and intensive medical therapy.

Common Misconceptions and Correct Methods

  • Scoring Errors and Their Prevention
  • Interpretation Pitfalls
  • Integration with Clinical Judgment
While the TIMI Score for UA NSTEMI is a valuable clinical tool, several common misconceptions can lead to incorrect risk assessment and suboptimal patient management. Understanding these pitfalls and implementing correct methods is essential for accurate risk stratification and optimal patient outcomes.
Common Scoring Errors and Prevention
One common error is double-counting coronary artery disease. The score includes both 'known CAD ≥50% stenosis' and 'known CAD stenosis ≥50%' as separate items, but these should not be counted twice if they refer to the same condition. Another error is misinterpreting ST changes, where minor ST-T wave abnormalities or changes attributable to bundle branch blocks or ventricular hypertrophy are incorrectly scored. Only ischemic ST changes ≥0.5mm should be counted.
Biomarker Interpretation Errors
Biomarker assessment errors include using outdated reference ranges or failing to consider the timing of biomarker measurement relative to symptom onset. Troponin levels may be normal early in the course of myocardial injury, requiring serial measurements. Additionally, elevated biomarkers from other causes (e.g., renal failure, heart failure) should not be counted unless clearly attributable to acute coronary syndrome.
Integration with Clinical Judgment
The TIMI Score should never be used in isolation but must be integrated with clinical judgment and other risk assessment tools. Patients with low TIMI scores but concerning clinical features (e.g., ongoing chest pain, hemodynamic instability) may still require aggressive management. Conversely, patients with high scores but stable clinical conditions may be managed more conservatively based on individual circumstances.

Prevention Strategies:

  • Always review angiographic reports to avoid double-counting CAD components.
  • Use serial biomarker measurements to ensure accurate assessment of myocardial injury.
  • Integrate TIMI Score with clinical presentation and other risk factors for comprehensive assessment.

Mathematical Derivation and Examples

  • Statistical Basis of the Scoring System
  • Validation Studies and Evidence
  • Clinical Examples and Case Studies
The TIMI Score for UA NSTEMI was developed using multivariate logistic regression analysis of data from the TIMI 11B trial, which enrolled 3,910 patients with UA NSTEMI. The seven variables were selected based on their independent predictive value for 14-day adverse events, with each component contributing equally to the final score based on statistical significance and clinical relevance.
Statistical Development and Validation
The original TIMI 11B trial demonstrated that each of the seven variables independently predicted adverse events, with odds ratios ranging from 1.3 to 2.1. The final score was validated in multiple subsequent trials, including TIMI 18 (TACTICS-TIMI 18) and TIMI 22 (PROVE IT-TIMI 22), confirming its predictive accuracy across different patient populations and treatment strategies. The score's c-statistic of 0.65-0.70 indicates good discriminative ability.
Risk Stratification and Event Rates
The TIMI Score stratifies patients into risk categories with significantly different event rates: Score 0-1 (4.7% event rate), Score 2 (8.3% event rate), Score 3 (13.2% event rate), Score 4 (19.9% event rate), Score 5 (26.2% event rate), and Score 6-7 (40.9% event rate). This gradient of risk allows for appropriate treatment intensity matching and resource allocation based on individual patient risk.
Clinical Application Examples
Consider a 70-year-old patient with known CAD, recent aspirin use, severe angina episodes, elevated troponin, and ST depression. This patient would score 6 points (age ≥65, known CAD, aspirin use, severe angina, elevated biomarkers, ST changes), placing them in the highest risk category with a 40.9% risk of adverse events, warranting immediate invasive evaluation and intensive medical therapy.

Mathematical Examples:

  • TIMI Score 2: 70-year-old with known CAD and elevated biomarkers (8.3% event rate).
  • TIMI Score 4: Patient with age ≥65, known CAD, severe angina, and ST changes (19.9% event rate).
  • TIMI Score 6: High-risk patient with multiple factors including biomarkers and ST changes (40.9% event rate).