The prediction of angiographic coronary thrombus burden using the admission GRACE 2.0 score in ST-elevation myocardial infarction patients

Abstract

Funding Acknowledgements Type of funding sources: None. Introduction Heavy coronary thrombus burden is associated with increased periprocedural complications in ST-elevation myocardial infarction (STEMI) patients undergoing primary PCI (PPCI)[1]. The prediction of such a burden can help in planning the PPCI procedure in the best way. The Global Registry of Acute Coronary Events (GRACE) 2.0 score is a useful non-invasive tool to predict major adverse events in STEMI patients [2]. Purpose to assess the difference in coronary thrombus burden in STEMI patients with low and high risk GRACE 2.0 score on admission. Methods We retrospectively studied 210 STEMI patients who presented to a single PPCI centre over a period of 6 months. We consecutively included all the patients who were eligible for PPCI according to the European Society of Cardiology (ESC) guidelines [2]. We excluded the patients who received fibrinolysis, who had a previous PCI and presented with in-stent thrombosis and those who presented more than 24 hours from the onset of chest pain. All procedures were done according to the Helsinki declaration of research on human beings. The study protocol was approved by the local research ethics committee. The GRACE 2.0 score was calculated at the time of presentation to the emergency department using the online calculator [3]. We divided the patients according to their GRACE 2.0 score into a high-risk score (more than 140) and a non-high-risk score(up to 140) groups according to the ESC guidance.2 We compared the two groups regarding various cardiovascular risk factors and the angiographic thrombus burden during the PPCI procedure. Two experienced interventional cardiologists (blinded to the allocation group) assessed the thrombus burden using the TIMI thrombus grades [4]. A heavy thrombus burden was defined as a thrombus grade of 4 or 5. A professional statistician carried out the statistical analysis using IBM SPSS 21.0 software. Results The baseline characteristics of the studied groups are shown in figure 1. Multivariate regression analysis did not show an influence of the different cardiovascular risk factors on the thrombus burden in the studied groups. The percentage of patients with a heavy thrombus burden was higher in the high-risk score group; however, the difference between the two groups was not statistically significant (44.6% vs 35.3%, P=0.46) (figure 2). This study is the first to assess the ability of the GRACE 2.0 score to predict the coronary thrombus burden in STEMI patients undergoing PPCI. The study is limited by the small number of patients included and the small geographical scale. Conclusion Although the GRACE 2.0 is a well-validated tool to predict the clinical prognosis in STEMI patients, it could not identify those patients with a high coronary thrombus burden in our small study. Further larger-scale studies are required to find other non-invasive tools to identify this high-risk cohort.