Free triiodothyronine and global registry of acute coronary events risk score on predicting long-term major adverse cardiac events in STEMI patients undergoing primary PCI

Background: The aim of this study is to investigate the combined value of fT3 and GRACE risk score for cardiovascular prognosis in ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI). Methods: Three hundred and thirty eight patients with STEMI who received successful primary PCI were enrolled in our study. All patients underwent (33.5 +/- 7.1) month's follow-up. Mace was defined as cardiac death and nonfatal myocardial infarction. Results: Multivariate Cox analysis showed that both fT3 (HR = 0.462, 95%CI: 0.364-0.587, P < 0.001) and GRACE score (HR = 1.011, 95%CI: 1.004-1.018, P = 0.003) were independent predictors of Mace. Similarly, fT3 (HR = 0.495, 95%CI: 0.355-0.690, P < 0.001) and GRACE score (HR = 1.022, 95%CI: 1.011-1.034, P < 0.001) were the most important independent predictors of cardiac death. Kaplan-Meier analysis revealed that those patients with low fT3 and higher GRACE score had higher rates of Mace (Log-Rank (X)2 = 25.087, P < 0.001). In ROC analysis, combining fT3 and GRACE risk score had a good area under the curve (AUC) value for Mace (AUC = 0.735, 95% CI: 0.680-0.790, P < 0.001), with net reclassification index of 11.1 and 5.3%, respectively. Conclusion: The low fT3 level, a common phenomenon, is a strong predictor of long-term poor prognosis in STEMI patients who underwent primary PCI. The combination of GRACE score and fT3 may be a more valuable predictor of Mace as compared to each measure alone.