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 χ2 = 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.