Your TIMI STEMI score predicts 30-day all-cause mortality following ST-elevation myocardial infarction. Scores range from 0 to 14 points. A score of 0-2 corresponds to low risk with approximately 2-4% 30-day mortality. A score of 3-4 indicates moderate risk with 7-12% mortality. A score of 5-6 represents high risk at 15-23% mortality. A score of 7 or above places the patient in the very high-risk category with 26-36% mortality.

The heavily weighted variables are systolic blood pressure below 100 mmHg (3 points) and age 65 or older (2 points), Killip class II-IV (2 points), and heart rate above 100 (2 points). The presence of hemodynamic instability (hypotension, tachycardia, heart failure) is the strongest predictor of poor outcome and should prompt immediate consideration of mechanical circulatory support and intensive hemodynamic monitoring.

Use the TIMI STEMI score at the time of presentation with confirmed ST-elevation myocardial infarction, ideally before or immediately after reperfusion therapy (primary PCI or fibrinolysis). It helps triage patients to appropriate levels of care: low-risk patients may be candidates for early step-down from the ICU, while high-risk patients benefit from aggressive hemodynamic support, prolonged monitoring, and possibly mechanical circulatory support devices.

The score is also useful for communicating prognosis to patients and families, for identifying candidates for clinical trials, and for quality benchmarking across institutions. It complements the GRACE score, which uses continuous variables and may offer better discrimination in some populations.

The TIMI STEMI score was derived from the InTIME II fibrinolytic trial, where all patients received fibrinolysis rather than primary PCI. Mortality rates have decreased substantially in the primary PCI era, so the absolute risk estimates may overpredict mortality in contemporary practice. However, the relative risk stratification (low vs. high risk) remains valid.

The score uses dichotomous cut-offs for continuous variables (e.g., age 65 is treated the same as age 90), which sacrifices some discriminative ability. The GRACE score, which uses continuous variable inputs, generally provides better calibration and discrimination and is recommended by ESC guidelines as the preferred ACS risk tool. The TIMI STEMI score does not account for important prognostic variables such as infarct location detail, time to reperfusion, left ventricular function, or multivessel disease.