TIMI Risk Score for UA/NSTEMI

Age ≥65

≥3 CAD Risk Factors

Known CAD (stenosis ≥50%)

ASA Use in Past 7 Days

Severe Angina (≥2 episodes in 24 hrs)

EKG ST Changes ≥0.5mm

Positive Cardiac Marker

TIMI UA/NSTEMI Score: 0

–

Estimates mortality for patients with unstable angina and non-ST elevation MI.

Why Use

UA/NSTEMI can sometimes be missed. Traditionally, the TIMI Risk Score for UA/NSTEMI can correlate the risk of adverse outcome in chest pain patients.

When to Use

Can be used to help risk stratify patients with presumed ischemic chest pain. However, it was originally derived in patients with confirmed unstable angina or non-ST elevation myocardial infarction.

Formula

Addition of the selected points: Variable Points Age ≥65 1 ≥3 CAD risk factors* 1 Known CAD (stenosis ≥50%) 1 ASA use in past 7 days 1 Severe angina (≥2 episodes in 24 hrs) 1 EKG ST changes ≥0.5mm 1 Positive cardiac marker 1 *Risk factors for CAD: Family history of CAD, hypertension, hypercholesterolemia, diabetes, or current smoker (thanks to Jeff Geske at Mayo for this update!)

Pearls / Pitfalls

One of the earliest chest pain decision rules that was widely implemented. Originally derived with patients with known unstable angina or NSTEMI. Newer chest pain risk scores such as the HEART Score have been shown to better stratify risk than the TIMI Score, particularly in the undifferentiated chest pain patient. A TIMI risk score of 0 or 1 does not equal zero risk of adverse outcome. The original study showed 4.7% of patients with a score of 0 or 1 had adverse outcomes within 14 days. Validation studies showed 1.7 to 2.1% of patients with a score of 0 still had adverse outcomes within 30 days. Unclear if this risk score can be used in patients with chest pain in the setting of cocaine use. The TIMI Score was further studied as part of an accelerated diagnostic protocol in the ADAPT trial, which includes estimation of pre-test probability using TIMI, plus abnormal EKG and troponin (high-sensitivity cardiac troponin I).

Management

If patients are in the 0 or 1 point group, they should be further risk stratified using another risk score or one’s own institutional practices, as risk is not low enough to safely discharge from the hospital. Many guidelines recommend higher risk levels receiving more aggressive medical intervention and/or receiving early invasive management.

Critical Actions

A TIMI Risk Score of 0 does not equate to zero risk of adverse outcome.

Advice

Patients with a score of 0 or 1 point are at lower risk of adverse outcome (death, MI, urgent revascularization) compared to patients with a higher risk score. However, the risk is not zero. Patients with a higher risk score may require more aggressive medical or procedural intervention. Newer chest pain risk scores such as the HEART Score have been shown to better stratify risk than the TIMI Score, particularly in the undifferentiated chest pain patient.