The TIMI Score is a widely used risk stratification tool in cardiology.
Specifically, the Thrombolysis in Myocardial Infarction (TIMI) Score is used to determine the likelihood of ischemic events or mortality in patients with unstable angina or non–ST-segment elevation myocardial infarction (NSTEMI). This score helps clinicians assess a patient's risk of experiencing adverse events, such as death, new myocardial infarction, or severe recurrent ischemia requiring urgent revascularization, within a specific timeframe (typically 14 or 30 days).
Understanding the TIMI Risk Score for UA/NSTEMI
The TIMI risk score provides valuable information to guide management decisions, including the intensity of medical therapy and the potential benefit of invasive strategies like angiography and revascularization.
How the TIMI Score is Calculated
The TIMI score for Unstable Angina (UA) and Non–ST-Segment Elevation Myocardial Infarction (NSTEMI) is calculated by assigning one point for the presence of each of the following seven risk factors:
- Age ≥ 65 years: Older patients are at higher risk.
- Presence of ≥ 3 risk factors for Coronary Artery Disease (CAD): These can include family history of premature CAD, hypertension, hypercholesterolemia, diabetes mellitus, or current cigarette smoking.
- Documented CAD with prior stenosis ≥ 50%: Previous significant narrowing of coronary arteries increases risk.
- Recent severe angina (within 24 hours): Indicates unstable coronary disease.
- Aspirin use in the past 7 days: Suggests existing CAD or risk factors for which aspirin was prescribed.
- Elevated serum cardiac biomarkers (e.g., CK-MB, troponin): Indicates myocardial injury.
- ST-segment deviation ≥ 0.5 mm on electrocardiogram (ECG): Suggests ongoing or recent ischemia.
A patient's total TIMI score is the sum of the points from these seven factors, ranging from 0 to 7.
Interpreting the TIMI Score
The total score correlates with the estimated risk of adverse outcomes:
| TIMI Score | Estimated Risk (%) of Death, MI, or Severe Ischemia at 14 Days | Risk Category |
|---|---|---|
| 0-1 | ~4.7 | Low Risk |
| 2 | ~8.3 | Low Risk |
| 3 | ~13.2 | Intermediate |
| 4 | ~19.9 | Intermediate |
| 5 | ~26.2 | High Risk |
| 6-7 | ~40.9 | High Risk |
Note: Risk percentages can vary slightly depending on the specific study population, but the general trend of increasing risk with increasing score is consistent.
Practical Application
Clinicians use the TIMI score to:
- Stratify Risk: Quickly identify patients who are at higher or lower risk of future events.
- Guide Therapy: Higher risk scores may prompt more aggressive medical treatment and an earlier invasive strategy (e.g., cardiac catheterization). Lower scores might suggest that conservative management is appropriate.
- Inform Patient Discussions: The score provides a framework for discussing prognosis and treatment options with patients.
By consolidating key clinical variables, the TIMI score serves as a valuable, easily calculable tool in the initial assessment and management of patients presenting with symptoms suggestive of unstable angina or NSTEMI.
Reference: The Thrombolysis in Myocardial Infarction (TIMI) Score is used to determine the likelihood of ischemic events or mortality in patients with unstable angina or non–ST-segment elevation myocardial infarction (NSTEMI). [1, 2, 3, 4, 5, 6]
