Background: Risk stratification in non-ST elevation ACS (NSTE-ACS) using the GRACE and the TIMI risk scores is essential as those identified to be high risk patients benefit most from early invasive treatment. These scoring systems should also be able to predict the patients' severity of coronary artery disease (CAD) anatomy because this may modify the management strategy. This study compared the discriminative ability and accuracy of these scoring systems in predicting the severity of CAD lesions in patients with NSTE-ACS.
Methods: This is a cross-sectional, analytic study involving NSTE-ACS patients admitted to the Philippine Heart Center from 2006 to 2016. The GRACE and TIMI risk scores were computed and the severity of CAD was established after review of individual coronary angiogram. The discriminative ability of the risk scores were determined using the area under the ROC curve statistics while the predictive accuracies were computed via sensitivity and specificity analyses.
Results: There were 200 subjects included in this study. The mean age was 70±12 years and majority (69%) were males. Fifty percent (50%) had high risk GRACE score, 59% had high risk TIMI score while 53.5% had severe CAD. The GRACE score had higher discriminatory ability compared to TIMI in identifying severe CAD (AUROC curve score of 0.77 versus 0.65, p=0.006). Severe CAD was also more accurately predicted by the GRACE score (specificity of 74.2%, sensitivity of 72% ) versus the TIMI (specificity of 61.6%, sensitivity of 68.2%). The cut off value for GRACE in detecting severe CAD was 138 while that of TIMI was 3.
Conclusion: The GRACE score identifies severe CAD with higher discriminatory ability and predictive accuracy compared to TIMI, therefore it is the favored risk stratification system to be used in Filipino patients with NSTE-ACS.