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Printed on 6/29/2026
For informational purposes only. This is not medical advice.
The TIMI risk score for STEMI uses 8 clinical variables to estimate 30-day mortality risk following ST-elevation myocardial infarction. Developed from the InTIME II trial, scores range 0–14 with higher scores predicting greater mortality, guiding the intensity of reperfusion and adjunctive therapy.
Formula: Age ≥65 (2) + DM/HTN/angina (1) + SBP<100 (3) + HR>100 (2) + Killip≥II (2) + Wt<67 (1) + Ant ST/LBBB (1) + Time>4h (1). Range 0–14.
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At the time of confirmed STEMI diagnosis, score nine readily available clinical variables: age ≥75 years (3 points), age 65-74 years (2 points), diabetes/hypertension/prior angina (1 point), systolic BP <100 mmHg (3 points), heart rate >100 bpm (2 points), Killip class II-IV (2 points), weight <67 kg (1 point), anterior ST elevation or new LBBB (1 point), and time to treatment >4 hours (1 point). All data are available before laboratory results.
Sum all scored items to get a total score ranging from 0 to 14 points. Scores 0-2 = low risk; 3-4 = moderate risk; 5-6 = high risk; ≥7 = very high risk. The most heavily weighted variables are SBP <100 (3 pts) and age ≥75 (3 pts), reflecting the dominance of hemodynamic instability and advanced age in determining STEMI mortality.
Score 0: 0.8% 30-day mortality; Score 1: 1.6%; Score 2: 2.2%; Score 3: 4.4%; Score 4: 7.3%; Score 5: 12%; Score 6: 16%; Score 7: 23%; Score 8+: 35%+. Use this risk estimate to guide intensity of post-PCI monitoring, ICU vs. step-down placement, mechanical circulatory support decisions, and prognostic communication with patients and families.
Emergency physicians, cardiologists, interventionalists
The TIMI STEMI score provides a standardized, quantitative 30-day mortality estimate at STEMI presentation. It is valuable for communicating risk to patients, families, and care teams when time permits during the acute phase.
Interventional cardiologists, cardiac intensive care nurses
After primary PCI, TIMI score guides appropriate care setting: low-risk STEMI (score 0-2) may be candidates for early step-down from ICU monitoring; high-risk STEMI (score ≥5) warrants prolonged ICU care with hemodynamic monitoring and readiness to escalate circulatory support.
Interventional cardiologists, heart failure specialists
Very high TIMI scores (≥7) combined with cardiogenic shock (Killip IV) identify patients who may benefit from Impella, intra-aortic balloon pump (IABP), or extracorporeal membrane oxygenation (ECMO) as hemodynamic support during and after primary PCI.
All clinicians caring for STEMI patients
A TIMI score of 7+ predicts 30-day mortality exceeding 23-35%, providing a concrete basis for early goals-of-care discussions with family when the patient cannot participate. This supports informed consent and advance directive conversations in the acute setting.
Catheterization laboratory directors, quality officers
TIMI STEMI score is used in catheterization laboratory quality improvement to risk-adjust STEMI mortality outcomes. Comparing observed to expected mortality rates (based on TIMI score distribution) enables meaningful institutional benchmarking and performance monitoring.
The TIMI STEMI score is a RISK STRATIFICATION tool, not a triage tool for reperfusion. All STEMI patients should receive primary PCI as first-line reperfusion, regardless of TIMI score. The score guides post-reperfusion intensity of care and monitoring, not the decision to perform PCI. Withholding PCI based on a high or low TIMI score would be inappropriate.
The most impactful intervention in STEMI is speed of reperfusion. Door-to-balloon time target is <90 minutes for patients presenting to a PCI-capable hospital and <120 minutes for transferred patients. Every 30-minute delay increases 1-year mortality by approximately 7.5%. The TIMI score is secondary to achieving rapid reperfusion — do not let scoring delay PCI.
Killip classification reflects hemodynamic status: Class I = no signs of HF; Class II = rales in lower lung fields, S3 gallop, or elevated JVP; Class III = frank pulmonary edema; Class IV = cardiogenic shock (SBP <90 despite resuscitation). Killip IV (cardiogenic shock) is present in ~7% of STEMI patients and carries 50-80% in-hospital mortality. These patients require urgent hemodynamic support.
In inferior STEMI, right ventricular MI may coexist (occurs in up to 40% of inferior STEMI). Right-sided ECG leads (V4R ST elevation ≥0.5 mm) confirm RV involvement. RV MI patients are preload-dependent — nitrates and diuretics are contraindicated as they reduce preload and can precipitate profound hypotension. IV fluids are the treatment for RV MI hypotension.
All STEMI patients receiving drug-eluting stents should receive dual antiplatelet therapy (aspirin + P2Y12 inhibitor) for 12 months per ACC/AHA guidelines. Ticagrelor (preferred) or prasugrel significantly reduces stent thrombosis and recurrent MI. Clopidogrel is an alternative if ticagrelor/prasugrel are contraindicated. Premature discontinuation of P2Y12 inhibitor markedly increases stent thrombosis risk.
The TIMI STEMI score was derived from the InTIME II trial using fibrinolysis (not primary PCI). Absolute 30-day mortality in contemporary primary PCI practice is lower than original TIMI predictions (overall STEMI mortality ~4-8% vs. original InTIME II data). The relative risk gradient across score levels remains valid, but absolute numbers should be interpreted in modern context.
Cardiogenic shock (Killip IV) at presentation is the leading cause of in-hospital STEMI death. Despite primary PCI, cardiogenic shock mortality remains 40-50%. Current evidence supports early revascularization of the culprit lesion (not routine multivessel PCI in shock per CULPRIT-SHOCK trial). Consider Impella or ECMO support and early transfer to a shock center for refractory cardiogenic shock.
For STEMI with multivessel disease without cardiogenic shock, the ACC/AHA and ESC guidelines support staged revascularization of non-culprit lesions at a separate procedure (either before discharge or within 45 days per COMPLETE trial). Routine immediate multivessel PCI at primary PCI in stable STEMI does not improve outcomes and may increase risk.
After primary PCI for STEMI, reassess LVEF at 6-12 weeks (not acutely). Patients with LVEF ≤35% on optimal GDMT at 3+ months qualify for ICD implantation for sudden cardiac death prevention. Acute post-MI LVEF may recover significantly — premature ICD implantation during hospitalization is not indicated in most cases.
TIMI Risk Score for STEMI developed by Morrow et al. (Circulation 2000) from 14,114 patients in the InTIME II trial of fibrinolytic therapy. C-statistic 0.78 for 30-day mortality. Validated in the primary PCI era by Garcia et al. (Eur Heart J 2007). Door-to-balloon time and mortality: Bradley et al. (NEJM 2006). ACC/AHA STEMI Guidelines: O'Gara et al. (JACC 2013), updated 2022 (Writing Committee of the 2013 ACCF/AHA Guideline). CULPRIT-SHOCK trial for cardiogenic shock management: Thiele et al. (NEJM 2017). PLATO trial for ticagrelor: Wallentin et al. (NEJM 2009). TRITON-TIMI 38 for prasugrel: Wiviott et al. (NEJM 2007).
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.
Disclaimer: This tool is for educational and informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider with questions about your health.
April 21, 2026 · trust-baseline
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