Evaluation Of Intracardiac Hemodynamics In Patients With Systemic Lupus Erythematosus By Vector Flow Mapping

Systemic lupus erythematosus(SLE)is a chronic autoimmune inflammatory connective tissue disease.Immune complex,during the development of SLE,can affect various organs,including lung,heart,kidney,brain,peripheral nerve,skin and serosa.Heart is one of the most frequently involved target organs.The pathophysiology of cardiac involvement in patients with SLE is different,the different clinical manifestations which are pericardial effusion,myocarditis,valvular disease,aseptic endocarditis,heart failure,ischemic heart disease and pulmonary hypertension.All these cardiovascular complications can contribute the high mortality of SLE.Therefore,it is important to evaluate SLE patients' cardiac involvement in an early,accurately,and comprehensively manner which can benefit the prognosis and treatment.At present,there are numerous techniques to evaluate the structure and function of the heart,such as X-ray,echocardiography,cardiac CT,cardiac magnetic resonance,cardiac catheterization,etc.Echocardiography is a simple and reliable diagnostic technique commonly used in clinic.Echocardiography techniques including two-dimensional echocardiography,tissue Doppler imaging and two-dimensional speckle tracking are used to evaluate the whole or local function of the heart,or myocardial movement.It is impossible to evaluate the flow field state and hemodynamic changes in the heart chamber,so it is not possible to comprehensively evaluate the pathophysiological changes of heart disease at an early stage.In recent years,more and more attention has been paid to the method of evaluating cardiac function by analyzing the changes of intracardiac fluid dynamics.Vector flow mapping(VFM)is a new visualized ultrasound technique for observing and evaluating the flow field and hemodynamics in cardiovascular system.It provides a reliable hydrodynamic information for the early diagnosis of heart disease.SLE patients may have no clinical symptoms in the early stage of the disease,but there are definite hemodynamic changes.There is no report on the use of VFM to evaluate the changes of intraventricular hemodynamics in SLE patients.ObjectiveTo analyze the changes of intraventricular hemodynamics in SLE patients and the relationship between intraventricular hemodynamics changes and cardiac function by vector flow mapping.To explore the value of vector flow mapping in evaluating cardiac involvement in SLE patients.MethodsSixty SLE patients were selected from August 2015 to August 2017 in the First Affiliated Hospital of Nanjing Medical University,and sixty-one healthy volunteers were selected as controls.Sixty SLE patients were divided into normal pulmonary artery pressure group(S1)and elevated pulmonary artery pressure group(S2)according to the internationally recommended diagnostic criteria of pulmonary artery hypertension(PAH)by transthoracic echocardiography.Using Aloka Pro Sound F75 ultrasound instrument,equipped with DAS-RS1 workstation and 2.0 version of vector flow mapping analysis software,the vortex and energy loss at each segment of the left ventricular chamber(total,basal,middle and apical segments)at the periods of the cardiac cycle(isovolumic contraction period,rapid ejection period,rapid filling period,reduced filling period,atrial contraction period)were obtained.ResultsCompared with the control group,the vortex in SLE group changed significantly in different phases.In early diastole(rapid filling period),middle diastole(reduced filling period)and isovolumic contraction period,the number of vortices in SLE group was significantly higher than that in control group(P < 0.01).In the middle diastolic period and rapid ejection period,the control group mostly showed a single large vortex.Many small vortices were observed in the SLE group,and the maximum vortex area was smaller than that in the control group.In SLE group,energy loss was the largest in early diastolic period,followed by middle and late diastolic period(atrial contraction period),energy loss was lower in isovolumic contraction period and the smallest in rapid ejection period.In SLE group,energy loss decreased from basal to middle to apical segments,with significant difference(P < 0.01).Compared with the control group,the energy loss in early,middle,late diastole and rapid ejection period in SLE group was significantly increased(P < 0.01).In each phase of a cardiac cycle,the energy loss of S2 group was significantly higher than that of S1 group and control group(P < 0.01).In rapid ejection period and isovolumic contraction period,the energy loss of S2 group was significantly higher than that of control group(P < 0.01).In SLE group,energy loss was negatively correlated with heart rate(r=-0.342 P< 0.01)and RVD(r=-0.367 P < 0.01)in early diastolic period.In early diastolic period,energy loss was positively correlated with peak velocity S(r=0.536 P < 0.01)and negatively correlated with Tei index(r=-0.284 P < 0.01).At the late diastole period,energy loss was positively correlated with LVDd(r = 0.299 P < 0.05).In early diastolic period,energy loss was positively correlated with interval E'(r= 0.784 P < 0.01).In late diastolic period,energy loss was positively correlated with interval E/e'(r = 0.812 P < 0.01)and A(r = 0.715 P < 0.01).During isovolumic contraction period,energy loss was positively correlated with interval E/e',peak A(r= 0.461 P < 0.01,r = 0.672 P < 0.01).During rapid ejection period,energy loss was positively correlated with TAPSE and FAC(r = 0.279 P < 0.05,r = 0.351 P < 0.01).In early diastolic period,energy loss was positively correlated with TAPSE and FAC(r = 0.317 P < 0.05,r = 0.296 P< 0.05).ConclusionVFM can not only comprehensively,rapidly and efficiently evaluate the changes of myocardial mechanics and intracardiac hemodynamics,but also observe and quantitatively analyze the complex information of intracardiac blood flow field in SLE patients.Therefore,VFM provides reliable hydrodynamic evidence for early and accurate assessment of cardiac function,judgment of the severity of cardiac diseases and evaluation of therapeutic effect,and plays an important role in clinical practice.