P847Performance of the GRACE score in patients with type 1 and type 2 myocardial infarction

Abstract Introduction The Global Registry of Acute Coronary Events (GRACE) score is a widely used risk stratification tool in the evaluation of patients with myocardial infarction. However, the performance of GRACE in patients with myocardial infarction secondary to oxygen supply-demand imbalance in the absence of atherothrombosis (type 2 myocardial infarction), is uncertain. Outcomes in patients with type 2 myocardial infarction are poor, and a risk stratification tool is urgently required. Methods We assessed the GRACE score in two cohorts of consecutive patients presenting to the Emergency Department with suspected acute coronary syndrome. One cohort was recruited as part of a stepped wedge cluster randomised controlled trial across ten hospitals in Scotland, and one cohort from a large tertiary centre in Sweden. All diagnoses were adjudicated according to the Fourth Universal Definition. We applied the GRACE 2.0 algorithm to estimate death at one year. We assessed model discrimination using the area under the receiver-operator-curve (AUC), and compared AUC between type 1 and type 2 myocardial infarction using the DeLong test. Calibration was assessed using the Hosmer-Lemeshow (HL) goodness of fit test. Results We identified 2,538 and 1,080 patients with type 1 myocardial infarction from the Scottish and Swedish cohorts, with death from any cause occurring in 378 (14.9%) and 112 (10.4%) patients, respectively. The AUC for the GRACE score was 0.843 (0.823–0.864) and 0.848 (0.810–0.886). There were 642 and 247 patients with type 2 myocardial infarction in the Scottish and Swedish cohorts, respectively, with death occurring in 144 (22.4%) and 57 (23.1%) patients. The AUC was 0.708 (0.662–0.754) and 0.733 (0.657–0.808), (P<0.001 for both compared to type 1 myocardial infarction). The results of the HL Test suggest that the calibration of the GRACE 2.0 score needs further improvement (Table). Evaluation of GRACE 2.0 algorithm Type 1 Myocardial Infarction Type 2 Myocardial Infarction Scotland (n=2,538) Sweden (n=1,080) Scotland (n=642) Sweden (n=247) Deaths 378 (14.9%) 112 (10.4%) 144 (22.4%) 57 (23.0%) AUC (C-statistic) 0.843 (0.823–0.864) 0.848 (0.810–0.886) 0.708 (0.662–0.754) 0.733 (0.657–0.808) P-value for HL <0.001 <0.001 <0.001 <0.001 AUC: Area Under the receiver-operator Curve; HL: Hosmer-Lemeshow test. Figure 1. ROC curves Conclusions The GRACE score provided excellent discrimination for all cause death at one year in two contemporary consecutive patient cohorts with tye 1 myocardial infarction. In patients with type 2 myocardial infarction, GRACE performed well, but recalibration or the development of novel risk scores has the potential to improve risk stratification.