The Correlation Between Cardiac Function And Thyroid Function In Ischemic Cardiomyopathy Patients

Background and objectiveBecause of the widespread application of coronary revascularization,the mortality of coronary heart disease(CHD)is significantly reduced.However,the incidence of ischemic cardiomyopathy(ICM)is increased year by year.According to the World Health Organization(WHO)reports,ICM remains one of the leading causes of death in cardiovascular system diseases(CVDs)around the world,which is the most common etiology of heart failure in developed countries.ICM is the usual form of cardiac dysfunction which is caused by long-term myocardial ischemia.Some studies demonstrated that the cardiac function deteriorated in ICM patients was significantly faster than that the heart failure caused by other diseases,and the survival rate of ICM patients was much lower in ICM patients.How to suppress the ventricular remodeling process and improve the cardiac function is the key to improve outcomes and the quality of life in ICM patients.The correlation between thyroid function and CVDs has been widely studied.Previous studies have found that thyroid hormones(THs)had cardioprotective effects,THs could alleviate the remodeling of left ventricle in AMI patients and reduce the incidence of ICM.The level of THs below the lower limit of normal reference value was related to the aggravation of coronary stenosis and increased heart failure readmission rate.However,there are few studies about the relationship between the level of thyroid hormone(THs)in the normal reference range and the cardiac function of ICM patients.In this study,we analyze the characteristics of thyroid function in different cardiac function grades in ICM patients with normal thyroid function and explore the relationship between the level of THs in the normal reference range and the cardiac function in ICM patients.Finally,we also deduce that lower value of THs in the normal reference range may affect the progression of cardiac dysfunction in euthyroid ICM patients.Further more,it will improve the life quality of ICM patients by prompting earlier intervention in potential cardiac dysfunction.Methods200 ischemic cardiomyopathy patients from the First Affiliated Hospital of Zhengzhou University from Jan 1,2017 to Aug 31,2018 were selected and divided into 4 groups according to the cardiac function grading standard of New York Heart Association.In addition,all the subjects were divided into 2 groups according to the left ventricular ejection fraction(LVEF).The basic information of the subjects were collected,which included age,gender,smoking status,the history of hypertension and diabetes mellitus,oral medication,and the blood biochemical indicators,thyroid function indicators and UCG indexes detected in our hospital.The coronary angiography data of each subject in recent 6 months were collected and assessed by Gensini scoring.SPSS 22.0 was used to analyze all the data.Firstly,the differences between baseline data and observation indexes were compared among different groups.Secondly,the correlation between thyroid function and cardiac function indexes was analyzed.Finally,the logistic regression analysis was used to identify the influence factors in ICM with HFrEF.Results1.According to NYHA cardiac function classification,the results of baseline data comparison of four groups of patients showed that there were significantly differences in the number of smokers,hypertension,oral drugs and in the level of HbAlc,HDL in four groups(P<0.05).Post hoc multiple comparisons showed that the level of HDL in NYHA class ? group was significantly lower than that in NYHA class ? group(P<0.0083).The number of subjects who took digoxin in NYHA class ? was significantly more than class ? and ? groups(P<0.0083).And the number of subjects who took beta-blocker in NYHA class ? group was more than NYHA class ? grpup,while the number of subjects who took beta-blocker in NYHA class ? group was more than NYHA class ? and ? groups(P<0.0083).2.The comparison of observation indexes in four groups of patients showed that the levels of FT3 and TSH were significantly different(P<0.05).Post hoc multiple comparisons showed that the level of FT3 in NYHA class ? and IV gruops were lower than that in NYHA class ? group(P<0.0083)and the level of FT3 in NYHA class ? gruop was lower than that in NYHA class ? group(P<0.0083).The level of TSH in NYHA class ? group was higher than that in NYHA class ? group(P=0.002).Pro-BNP in the NYHA class ? group was higher than that in other three groups(P<0.0083)and pro-BNP in the NYHA class ? group was higher than that in NYHA class ? group(P<0.0083).The LVEDD in NYHA class ? and ? groups were larger than that in NYHA class ? group(P<0.0083).The LVEF in NYHA class? and ? groups were lower than that in NYHA class ? group(P<0.0083).The Gensini scores in NYHA class ? and ? groups were higher than that in NYHA class I group(P<0.0083).3.Grouping by LVEF,the baseline data showed that HFrEF group had more male subjects,and the difference of gender between the two groups was statistically significant(P<0.05).The number of smokers in HFrEF group was more than non-HFrEF group(P<0.05).The number of patients who took ACEI/ARB?digoxin and beta-blocker in HFrEF group was respectively more than non-HFrEF group(P<0.05).4.The level of FT3 in HFrEF group was lower than that in non-HFrEF group(P<0.05)and the level of TSH in HFrEF group was higher than that in non-HFrEF group(P<0.05).The LAD and LVEDD in HFrEF group were larger than that in non-HFrEF group(P<0.05).The level of pro-BNP in HFrEF group was higher than that in non-HFrEF group(P<0.05).5.The results of correlation analysis showed that the level of FT3 was negatively correlated with NYHA cardiac classification(r=-0.435,P<0.05)and pro-BNP(r=-0.448,P<0.05),while the level of FT3 was postively correlated with LVEF(r=0.210,P<0.05).The level of FT4 was negatively correlated with pro-BNP(r=-0.383,P<0.05),while it was postively correlated with LVEF(r=0.184,P<0.05).The level of TSH was postively correlated with NYHA cardiac classification(r=0.529,P<0.05)and pro-BNP(r=0.209,P<0.05),while the level of TSH was negatively correlated with LVEF(r=-0.217,P<0.05).6.Univariate and multivariate logistic regression showed that the higher level of TSH was the significant risk factor in ICM patients with HFrEF(OR=1.270,95%CI:1.048-1.538;P=0.015),while ACEI/ARB(OR=0.143,95%CI:0.059-0.345;P<0.001),digoxin(OR=0.150,95%CI:0.040-0.569;P=0.005),beta-blocker(OR=0.469,95%CI:0.226-0.973;P=0.042)were significant protective factors for ICM patients with HFrEF.Conclusions1.With the deterioration of cardiac function in ICM patients,the level of FT3 in the normal reference range is gradually decreased,while the level of TSH tends to elevate,which suggests that the FT3 and TSH may be related to the progress of cardiac dysfunction in ICM patients.2.The increased level of TSH is an important risk factor of ICM with HFrEF,which can help to evaluate the severity of cardiac insufficiency in ICM patients.3.In the clinical practice,the influence of the normal lower value of THs in ICM patients may indicate potential cardiac dysfunction,which may be helpful to manage the ICM patients comprehensively.