TIMI Risk Score Calculator

The TIMI risk score for unstable angina and NSTEMI deliberately uses seven equally weighted, simple binary criteria — age 65 or older, three or more coronary risk factors, known coronary artery disease (stenosis ≥50%), aspirin use in the prior seven days, severe angina (two or more episodes in 24 hours), ST-segment deviation on ECG, and elevated cardiac biomarkers — so it can be calculated in under a minute at the bedside without any additional testing beyond what's already been ordered for a chest-pain workup. Each criterion contributes exactly 1 point, and the total (0-7) maps directly onto observed 14-day rates of death, new or recurrent myocardial infarction, or urgent revascularization: roughly 5% at a score of 0-1, climbing to over 40% at a score of 6-7. Because the score correlates with event risk this cleanly, it has been used not just for prognosis but to guide treatment intensity — higher scores support an early invasive strategy (prompt angiography) and more aggressive antiplatelet/anticoagulant therapy, while very low scores support a more conservative, ischemia-guided approach. A related but distinct TIMI score exists for STEMI risk stratification, using a different and non-interchangeable set of criteria, so the two should not be confused despite sharing the TIMI name.

The score originates from the Thrombolysis in Myocardial Infarction (TIMI) research group, one of the most influential cardiovascular clinical trial collaboratives of the late 20th century, which had already produced the TIMI flow grading system for angiographic coronary reperfusion. Elliott Antman and colleagues derived and validated the UA/NSTEMI risk score using data from the TIMI 11B trial, publishing the result in JAMA in 2000 as a way to risk-stratify patients enrolled in that and subsequent trials of antithrombotic therapy. The score was deliberately built for simplicity from the outset — a stated design goal was that any clinician should be able to calculate it from information already available on a standard chest-pain admission without ordering additional tests — which drove its rapid adoption into everyday emergency medicine and cardiology practice well beyond its original clinical-trial risk-stratification purpose. It has been incorporated into ACC/AHA non-ST-elevation acute coronary syndrome management guidelines as one of the recommended tools (alongside the GRACE score) for deciding between an early invasive versus conservative management strategy, and remains widely taught and used in emergency departments and cardiology wards.