The role of GRACE score in the prediction of high-risk coronary anatomy in patients with non-ST elevation acute coronary syndrome.

Background: In patients with non-ST elevation acute coronary syndrome (NSTE-ACS), identification of the patients with high-risk coronary anatomy (HRCA) who are most likely to require coronary artery bypass grafting (CABG) is crucial. The SYNTAX score (SXscore) is an angiographic grading tool designed to determine the complexity of coronary artery disease. It appears that CABG offers significantly better outcomes in patients with SXscore ≥ 33, which shows severe HRCA.

Aim: We sought to assess the accuracy of the GRACE score in predicting HRCA in terms of SXscore in patients with NSTE-ACS.

Methods: Patients admitted to our coronary unit with a diagnosis of NSTE-ACS and undergoing coronary angiography during hospitalisation were recruited to this study. Patients were categorised into two groups based on SXscore: HRCA (SXscore ≥ 33) and low-risk coronary anatomy (LRCA, SXscore < 33). The cut-off level of GRACE score for HRCA was established by receiver operator characteristic (ROC) analysis.

Results: We studied 207 consecutive patients (mean age: 59 ± 11 years, 27.5% female). The GRACE score was 139 ± 34 in the HRCA group and 114 ± 33 in the LRCA group (p = 0.001). There was a significant positive correlation between SXscore and GRACE score (r = 0.338, p < 0.001). The area under ROC curve for GRACE score was 0.71 (95% CI 0.60-0.81, p = 0.001). A GRACE score of 123 was identified as the optimal cut-off to predict HRCA with a sensitivity of 71% and a specificity of 60%. In multivariate regression analysis, GRACE score ≥ 123 was the only variable that identified HRCA (OR 2.8, 95% CI 1.18-6.6, p = 0.019).Conclusions: Our study demonstrates that, in the setting of NSTE-ACS, patients with HRCA, who are most likely to require CABG, have higher GRACE scores at presentation. However, the ability of GRACE score to predict HRCA was modest.