Long-term prognostic value of free triiodothyronine and cardiac magnetic resonance imaging in dilated cardiomyopathy

Abstract

Objective To investigate the predictive value of free triiodothyronine (FT3) and cardiac magnetic resonance imaging (CMRI) in the long-term prognosis of patients with dilated cardiomyopathy (DCM). Methods Two hundred and twenty patients hospitalized at the Chinese Academy of Medical Sciences, Fuwai hospital from January 2010 to October 2011, with the diagnosis of DCM, were consecutively enrolled in our study.All patients enrolled underwent the test of thyroid function and CMR.Patients were divided into four groups according to the level of FT3 (median level of 2.79 pg/ml) and the presence or absence of late gadolinium enhancement (LGE) detected by CMRI: LGE-positive + FT3<2.79 pg/ml (n= 56), LGE-positive + FT3≥2.79 pg/ml (n=45), LGE-negative+ FT3<2.79 pg/ml (n=54) and LGE-negative + FT3≥2.79 pg/ml (n=65). The endpoint of our study included the events of sudden cardiac death (SCD), death caused by heart failure or cardiac transplantation.The association of events and four groups was assessed by Kaplan-Meier survival curve and multivariable Cox regression hazard model. Results There were 59 (26.8%) endpoint events including SCD, death caused by heart failure or cardiac transplantation occurred during the median follow-up of 61 months.There was a significant difference between the four groups (P<0.001). The rates of endpoint events were 51.8%(29/56), 24.4%(11/45), 22.2%(12/54)and 10.8%(7/65)in the patients with LGE-positive+ FT3<2.79 pg/ml, LGE-positive+ FT3≥2.79 pg/ml, LGE-negative+ FT3<2.79 pg/ml and LGE-negative+ FT3≥2.79 pg/ml, respectively.In multivariable Cox regression analysis, the adjusted risk of the endpoint events was 4.643 times higher in the LGE-positive+ FT3<2.79 pg/ml group than the LGE-negative+ FT3≥2.79 pg/ml group (95%CI= 1.817-11.87, P=0.001). Conclusions The combination of FT3 and LGE detected by CMRI provides predictive value for the long-term prognosis in patients with DCM. Key words: Cardiomyopathy, Dilated; Triiodothyronine; Magnetic resonance imaging; Prognosis