Are TIMI, GRACE, and HEART Scores the Same for NSTEMI?
No, TIMI, GRACE, and HEART scores are distinct risk stratification tools that differ in their components, intended populations, predicted outcomes, and discriminative accuracy for NSTEMI patients. 1, 2
Key Differences Between the Three Scores
Components and Variables
GRACE score uses 8 variables: age, Killip class, systolic blood pressure, heart rate, ST-segment deviation, cardiac arrest at presentation, serum creatinine, and positive cardiac biomarkers, capturing both hemodynamic instability and underlying disease severity 1, 2
TIMI score uses 7 equally-weighted variables: age ≥65 years, ≥3 CAD risk factors, known coronary stenosis ≥50%, ST-segment deviation, ≥2 anginal episodes within 24 hours, aspirin use in prior 7 days, and elevated cardiac biomarkers 1, 3
HEART score uses 5 components: History (0-2 points based on suspicion level), ECG findings, Age (<45-65, >65 years), Risk factors (number of traditional CAD risk factors), and Troponin level 1, 2
Intended Patient Populations
GRACE and TIMI scores were derived and validated specifically among patients with confirmed acute coronary syndromes (ACS), making them appropriate for NSTEMI patients after diagnosis 1
HEART score was derived and validated in emergency department patients with undifferentiated chest pain before ACS is confirmed or excluded, making it more suitable for initial ED evaluation 1, 2
Predicted Outcomes
GRACE score predicts: in-hospital mortality, 6-month mortality, 1-year mortality, 3-year mortality, and combined death/MI at 1 year 1, 2
TIMI score predicts: 14-day all-cause death, MI, or urgent revascularization in NSTEMI/unstable angina patients 1, 3
HEART score predicts: 30-day major adverse cardiovascular events (all-cause mortality, MI, or coronary revascularization) 1, 2
Comparative Performance in NSTEMI
Discriminative Accuracy
GRACE demonstrates superior predictive accuracy compared to TIMI for both in-hospital and long-term outcomes in NSTEMI patients. 4, 5, 6
GRACE shows a C-statistic of 0.83 for predicting in-hospital death across all ACS presentations, significantly outperforming TIMI 2, 4
In a large East Asian NSTEMI cohort, GRACE had an AUC of 0.82 for in-hospital events versus TIMI's 0.62 (p<0.05), and 0.89 versus 0.68 for long-term mortality (p<0.05) 4
For long-term prognosis (8-year follow-up), GRACE maintained an AUC of 0.734 in both STEMI and NSTEMI patients, significantly higher than TIMI (0.665-0.675) and HEART (0.611-0.632) 5
Risk Stratification Patterns
GRACE classifies most NSTEMI patients (45.7%) as high-risk, while TIMI groups the majority (61.2%) into intermediate risk 4
Among patients classified as TIMI intermediate risk, 53.5% were actually GRACE high-risk (≥140), with this subgroup experiencing significantly higher in-hospital events (39.5% vs 9.1%, p<0.05) and 4-year mortality (22.2% vs 0%, p<0.001) 4
HEART score performs better than TIMI for predicting 30-day MACE in NSTEACS patients, with both HEART and GRACE outperforming TIMI in emergency department populations 7
Clinical Application Algorithm for NSTEMI
Step 1: Initial ED Evaluation (Before Diagnosis Confirmed)
- Calculate HEART score for patients with undifferentiated chest pain to determine disposition 1, 2
- HEART 0-3 (low risk): <1% 30-day MACE rate, consider discharge with outpatient follow-up 2
- HEART 4-6 (intermediate risk): 8-20% MACE rate, requires observation and further evaluation 2
- HEART 7-10 (high risk): >26% MACE rate, admit for aggressive therapy 2
Step 2: After NSTEMI Diagnosis Confirmed
- Calculate GRACE score immediately at admission as the primary risk stratification tool 1, 2
- GRACE >140 defines high-risk patients requiring early invasive strategy within 24 hours 1, 2
- GRACE score predicts multiple time-point outcomes (in-hospital, 6-month, 1-year, 3-year mortality) 1, 2
Step 3: Sequential Use for Enhanced Discrimination
- If using TIMI for convenience, always add GRACE scoring for patients in TIMI intermediate-risk category to identify the 53.5% who are actually high-risk 4
- This combined approach preserves scoring convenience while maintaining predictive accuracy 4
Critical Pitfalls to Avoid
Do not use HEART score as the primary tool for confirmed NSTEMI patients—it was designed for undifferentiated chest pain populations and has inferior long-term prognostic ability compared to GRACE 1, 5
Do not rely solely on TIMI score for NSTEMI risk stratification—it has inferior discriminative accuracy compared to GRACE and may misclassify over half of high-risk patients as intermediate risk 1, 4, 6
Do not assume normal ECG reduces risk sufficiently in NSTEMI—10-17% of ACS patients with normal ECGs still experience MACE, requiring consideration of other risk factors 2
Do not discharge patients with HEART scores ≥7 without definitive evaluation—their 30-day MACE risk exceeds 26% 2