TIMI Risk Score Categories
The TIMI risk score for Unstable Angina/NSTEMI consists of 7 variables, each worth 1 point, with scores ranging from 0-7 that predict increasing risk of adverse cardiac events. 1
TIMI Risk Score Variables
The TIMI risk score includes the following 7 independent risk indicators, with 1 point assigned for each:
- Age ≥65 years
- At least 3 risk factors for coronary artery disease
- Prior coronary stenosis of ≥50%
- ST-segment deviation on ECG presentation
- At least 2 anginal events in prior 24 hours
- Use of aspirin in prior 7 days
- Elevated serum cardiac biomarkers 1
Risk Categories and Associated Outcomes
The TIMI risk score stratifies patients into risk categories that predict the likelihood of all-cause mortality, new or recurrent MI, or severe recurrent ischemia requiring urgent revascularization within 14 days:
| TIMI Risk Score | Risk of Adverse Cardiac Events (14 days) |
|---|---|
| 0-1 | 4.7% |
| 2 | 8.3% |
| 3 | 13.2% |
| 4 | 19.9% |
| 5 | 26.2% |
| 6-7 | 40.9% |
Clinical Application
The TIMI risk score is commonly used to guide treatment decisions:
- Low risk (score 0-2): Generally managed with conservative strategies
- Intermediate risk (score 3-4): May benefit from early invasive strategies
- High risk (score ≥5): Strongly benefit from early invasive strategies 1
For clinical decision-making:
- Scores of 0-2 are associated with lower risk of adverse outcomes
- Scores of 3-4 indicate intermediate risk
- Scores of 5-7 indicate high risk with substantially increased mortality and morbidity 2
Validation and Predictive Value
The TIMI risk score has been validated in multiple trials and cohorts, demonstrating good predictive ability for both short-term and long-term outcomes. The score remains a significant predictor of events even when information about some variables (such as prior coronary stenosis) is missing 1.
While the American College of Cardiology recommends the GRACE score as the primary tool for predicting mortality in ACS patients due to its superior predictive ability, the TIMI score remains valuable for initial decision-making due to its simplicity and ease of use at the bedside 2.
Important Considerations
- The TIMI risk score should be calculated at the time of admission
- It helps identify patients who may benefit most from aggressive interventions
- The score has been shown to predict not only 14-day outcomes but also 30-day and 1-year mortality 3
- Higher TIMI scores are associated with increased risk of bleeding complications in patients undergoing PCI 4
The TIMI risk score calculator is available at www.timi.org for clinical use 1.