Predictive Accuracy of TIMI, HEART, and GRACE Scores for Coronary Artery Disease Severity in NSTEMI/Unstable Angina – A Prospective Study from an Academic Emergency Department in Rural India

Aim: Scoring systems used to risk stratify patients with suspected non-ST-segment elevation myocardial infarction (NSTEMI)/ unstable angina (UA) for clinical decision-making in the Emergency Department (ED) are validated for outcomes, mortality, or adverse events but not evaluated for their predictive accuracy of the severity of coronary vessel involvement. With this objective, we studied how accurately Thrombolysis In Myocardial Infarction (TIMI), History, Electrocardiogram, Age, Risk Factors, Troponin (HEART), and Global Registry of Acute Coronary Events (GRACE) scores risk stratify patients with suspected NSTEMI/UA for the severity of coronary artery disease (CAD). Material and Methods: This was a prospective observational study of one year among patients who presented with UA and NSTEMI at a tertiary care teaching hospital ED in rural India. The primary outcome was quantified using the Gensini score following angiographic assessment of CAD severity. Results: Among 179 patients of mean age 61.18 ± 10.64, the median TIMI, HEART and GRACE scores were 2 (IQR: 1-3), 7 (IQR: 6-8) and 89 (IQR: 78-118), respectively. The TIMI score had no significant association with the Gensini score (p = 0.098), and 46.1% of patients classified as low-risk by TIMI score had severe CAD. Both HEART (p < 0.001) and GRACE scores (p = 0.049) were significantly associated with Gensini scores. TIMI Score had an Area under the Curve (AUC) of 0.620 [95% CI: 0.534-0.706; p = 0.008], HEART score showed an AUC of 0.632 (95% CI: 0.547-0.717; p = 0.004), and GRACE score had an AUC of 0.606 (95% CI: 0.519-0.693; p = 0.020). Conclusion: HEART score demonstrated the numerically highest AUC among the three scores; however, all scores showed only modest discriminatory ability in predicting angiographic CAD severity. These findings suggest that commonly used clinical risk scores may provide some insight into angiographic disease burden, but should not be considered as substitutes for anatomical assessment.