TIMI Risk Score (UA/NSTEMI)
The TIMI risk score for unstable angina/NSTEMI estimates the probability of death, MI, or severe recurrent ischaemia requiring urgent revascularisation within 14 days. It uses 7 binary variables available at the time of presentation.
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✓ when to use
Use in patients presenting with UA or NSTEMI to guide intensity of antiplatelet/antithrombotic therapy and decision for early vs delayed invasive strategy. Higher TIMI scores support more aggressive management. Complements the HEART score (which is better for identifying low-risk patients for discharge) and GRACE score (which provides more granular mortality estimation).
✗ when not to use
The TIMI UA/NSTEMI score is NOT the same as the TIMI STEMI score (which uses different variables and is for STEMI prognosis). Not intended for patients with clear STEMI or non-cardiac chest pain. The 'aspirin use in past 7 days' criterion reflects aspirin failure and is sometimes counterintuitive.
clinical pearls
- TIMI and HEART serve different purposes. HEART is best for identifying low-risk patients who can be safely discharged (HEART 0–3). TIMI is better for risk-stratifying moderate-to-high risk patients to guide invasive strategy. They are complementary, not competing.
- The 'aspirin use in past 7 days' criterion is often misunderstood. It is a marker of aspirin failure (the patient had an ACS event despite being on aspirin) and reflects a higher-risk population — it does NOT mean aspirin use is a risk factor for ACS.
- GRACE score is generally preferred over TIMI for mortality prediction in ACS guidelines, as it provides a continuous risk estimate rather than integer categories and includes additional prognostic variables (heart rate, creatinine, killip class).
- A TIMI score ≥3 generally supports an early invasive strategy (coronary angiography within 24–72 hours) in patients with NSTEMI, though the decision depends on multiple factors including clinical stability, bleeding risk, and patient preference.
- The TIMI score does not include renal function or haemodynamic status, both of which are important independent predictors of outcome in ACS. Consider these alongside the score.