The Cardiac Function Assessment In Patients With Peripartum Cardiomyopathy

Background:Peripartum cardiomyopathy(PPCM)is a rare cause of heart failure that develops in the last month of pregnancy or within 5 months of delivery and the left ventricular ejection fraction(LVEF)<45%is a necessary diagnostic criteria.As we know,LVEF is not only affected by myocardial contractility,but also by many other factors such as preload and afterload and heart rate.Therefore,LVEF is not a reliable indicator for left ventricular function assessment.There are few studies on the application of left ventricular global function index(LVGFI)to evaluate left ventricular function till now.Objective:To explore the validity of the LVGFI by using ultrasound cardiogram(UCG)in assessment left ventricular function of PPCM patients with different LVEF.Medthods:A retrospective analysis was conducted among 25 patients with peripartum cardiomyopathy who were admitted to Shenzhen Baoan People’s Hospital and Shenzhen People’s Hospital from Jan.1,2010 to Dec.31,2020.The general information of patients and the levels of hemoglobin,troponin I(cTnI),N-terminal brain natriuretic peptide(NT-proBNP),and New York Heart Association(NYHA)cardiac function classification were collected,and the lowest level of hemoglobin and worst of NYHA classification were chosen during hospitalization,and the highest levels of cTnI,BNP/NT-proBNP were chosen alternatively;UCG parameters(for repeated testing of UCG,take data at the most severe condition)include:(1)Conventional two-dimensional UCG indicators:LVEDd,LVESd,LVEF,LVFS,IVS and LVPW;(2)Left ventricular systolic function index:LVEF(using Simpson method),the peak mitral annulus systolic velocity(S’)[Using Tissue doppler imaging,TDI];(3)To calculate EDV,ESV,SV,Mean arterial pressure(MAP),Cardiac output(CO),Cardiac power output(CPO=(CO*MAP)/451),LVmass,LVGFI.PPCM was defined by the following criteria:(1)patient meeting Framingham criteria for HF,(2)onset of HF during the last month of pregnancy or up to 5 months after delivery,(3)absence of an identifiable cause of HF,(4)absence of recognizable heart disease or HF before the last month of pregnancy.According to LVEF,they were divided into rPPCM group(LVEF<45%)and pPPCM group(LVEF≥45%).The included PPCM patients were classified into 2 groups(ie.Group mild vs.Group severe)according to the New York Heart Association(NHYA)cardiac function classification.Patients with cardiac function of the NYHA Class I and II were defined as Group mild,and the other(the NYHA Class Ⅲ and Ⅳ)were defined as Group severe heart failure group.Twenty-six healthy pregnant women with matching age,gestational age and postpartum time were randomly selected as the control group.Result:(1)Twenty-five cases of PPCM were included,ranging in age from 19 to 47 years old,with an average age of(30.48±6.97)years old,and an average LVEF value of(46.24±11.24)%,of which nine cases(36%)had cardiac function in NYHA grade Ⅱ.Most of the heart function is at grade Ⅲ and Ⅳ,with sixteen cases(64%).And rPPCM 12 cases,pPPCM 13 cases.The age rang of the control group including twenty-six cases was 19 to 44 years old,with an average age of(32.85±5.91)years old,and an average LVEF value of(65.54±6.16)%.There were no significant differences in age,gestational age,parity,LVmass,and ESV between the two groups(p>0.05).There were differences in heart rate,systolic blood pressure,diastolic blood pressure,mean arterial pressure,hemoglobin,NT-proBNP,IVS,LVPW,LVESd,LVEDd,EDV,SV,FS,LVEF,CO,CPO,LVGFI between the two groups(p<0.05),the NT-proBNP of the PPCM group was significantly higher than that of the control group(p<0.05),while the LVEF and LVGFI of the PPCM group were significantly lower than the control group(p<0.01).(2)NT-proBNP was significantly increased between the mild and severe heart failure groups,and the LVEDd was significantly enlarged.The LVGFI of severe heart failure group was lower than that of the mild heart failure group with significant difference(p<0.01),indicating that the more severe the heart failure,the lower LVGFI.However,the LVEF in mild and severe heart failure groups was not statistically significant,reflecting that LVEF be not a good marker of cardiac function status of PPCM patients.Logistic regression analysis showed that LVGFI[β=-1.22,OR=0.30,95%CI(0.11,0.80),p<0.05]can predict the severity of cardiac function in patients with PPCM,and it is negatively correlated with the severity of cardiac function.(3)LVGFI and LVEF are both negatively correlated with NT-proBNP,and the correlation coefficients of the two are as follows:LVGFI(R=-0.85,p<0.01),LVEF(R=-0.60,p<0.01).And the same negatively correlated with cardiac function classification,correlation coefficients are-0.64 and-0.33 respectively.The results show that compared with LVEF,LVGFI is more closely related to heart function.(4)The effectiveness of LVGFI in discriminating the severity of cardiac function:When the cut-off value of LVGFI is 17.41%,the predictive value for evaluating the severity of cardiac function in PPCM patients is the best,with a sensitivity and specificity of 87.5%,77.8%,respectively.And the area under the ROC curve(AUC)was 0.88(95%CI:0.69～0.98)(p<0.01).The area under the ROC curve of LVEF and CO are 0.70(95%CI:0.48～0.86)(p>0.05)and 0.53(95%CI:0.32～0.73,p>0.05),suggesting that LVGFI is better than LVEF in assessing the severity of cardiac function in patients with PPCM.Conclusion:Left ventricular global function index(LVGFI)is close related to the severity of heart failure,and so as to assessing the left ventricular function in patients with peripartum cardiomyopathy with clinical application validity.LVGFI is superior to LVEF.Peripartum cardiomyopathy with preserved ejection fraction is a subtype that does exist in clinical practice.