Analysis Of Left Ventricular Hemodynamic In Patients With Stage 1-3 Chronic Kidney Disease Using Vector Flow Mapping

Chronic kidney disease(CKD)has always been a burden to the whole society,and its incidence rate remains high worldwide.According to the KDOQI standard,it is divided into 5 stages.Patients with stages 1-3 CKD have a high cardiovascular morbidity and mortality compared with healthy people.However,the changes in cardiac structure and volume are relatively slight in stage 1-3 CKD patients who always have a preserved cardiac ejection fraction.Actually,diffuse myocardial interstitial fibrosis indeed occurs in stage 1-3 CKD,resulting in abnormality of intracardiac blood flow status.Therefore,accurate and reproducible evaluation on the early cardiac dysfunction were urgently need from the perspective of fluid dynamics in stages 1–3 CKD when the best opportunity of effective treatment exists.Vector flow mapping(VFM)is a novel technique for evaluating the intracardiac blood flow status.Compared to the other techniques,VFM is more suitable for clinical application owing to its convenient,non-invasive and inexpensive characteristics,and its accuracy has been confirmed by particle imaging velocimetry.Additionally,VFM,as a new echocardiographic technique,has no angle dependence or limitation of the region of interest,making it superior to traditional Doppler technology.Based on VFM technology,we can not only clearly display the blood flow status in heart cavity conveniently,but also analysis the blood flow quantitatively.Energy loss(EL)and the parameters about vortex are new quantified parameters of hydrodynamic under VFM technology,which reflect the flow efficiency and flow field of the cardiac cavity respectively.The repeatability and effectiveness of these new parameters have been demonstrated by a large number of studies.Recently,VFM has been gradually applied to the evaluation of cardiac function in CKD patients.One study successfully applied VFM to quantitatively evaluate left ventricular hemodynamics in patients with uremia(advanced CKD),confirming VFM bas efficacy in evaluation of intracardiac fluid dynamics in CKD hearts.Although patients with stages 1-3 CKD(early-stage CKD)seems not to experience volume shifts and obvious left ventricular hypertrophy compared with stages 4-5 CKD patients,intracardiac blood flow status has pathologically changed in their heart partly owing to the diffuse myocardial interstitial fibrosis.We speculated that VFM could provide some novel echocardiographic parameters for assessing their cardiac dysfunction in terms of fluid mechanics,but the related research has not yet been known.Importantly,hypertension,as a main cardiovascular risk factor,is frequently detected in patients with stage 1-3 CKD,unfortunately,it does not get enough attention in real-world until a serious cardiovascular event unexpectedly occurs.Additionally,whether the hypertension have further effect on the blood flow efficiency in patients with stages 1-3 CKD remains largely unknown.Therefore,we quantitatively detected the left ventricular blood flow in stage 1-3 CKD patients using VFM,and further focused on the change of left ventricular blood flow in patients with poorly controlled hypertension.This study was expected to provide valuable clinical data to reduce the disproportionately risk of cardiovascular disease and slow,or halt the damage about heart in CKD patients during the early stages.Part one: Assessment of Left Ventricular Energy Loss in Patients with Stages 1-3 Chronic Kidney Disease using Vector Flow MappingObjective: Patients with stages 1-3 CKD experience abnormality of intracardiac blood flow status during early-stages of disease.Left ventricular EL derived from VFM represents fluid energy lost as heat in left ventricle and had been used to detect intracardiac blood flow efficiency.We aimed to evaluate the left ventricular EL in stage 1-3 CKD patients,and explored whether hypertension,a main cardiovascular risk,deteriorate the abnormality of intracardiac blood flow status.Methods: Patients with CKD(KDOQI stages 1-3)who accepted professional treatment according to CKD clinical guidelines in the Second Hospital of Hebei Medical University from 2016 to 2018 were invited to participate this study.The criteria for enrollment were stable stage 1–3 CKD patients with primary glomerulonephritis(diagnosis with kidney puncture),adequate echocardiograms with sinus rhythm.Exclusion criteria were clinical evidence of heart failure,substantial valvular stenosis or regurgitation,and a history of angina pectoris or myocardial infarction,congenital heart disease,hypertrophic cardiomyopathy,pulmonary heart disease,essential hypertension and diabetes.Overall,this study recruited 48 stage 1-3 CKD patients and 41 controls.Transthoracic echocardiography was performed.CKD patients consisted a subgroup with no hypertension(N-HTN),a subgroup with well-controlled hypertension(W-HTN)and a subgroup with poorly controlled hypertension(P-HTN).The EL were calculated in the left ventricle using VFM analysis from the apical 3-chamber view.Furthermore,the correlation and stepwise multiple regression analysis were used to explore the potential independent predictors of left ventricular EL.Results: Compared with controls,stage 1-3 CKD patients showed increased left ventricular EL during total diastole,late diastole,total systole,isovolumic contraction and ejection.CKD patients with poorly controlled hypertension had higher left ventricular EL compared to the other CKD subgroups.Additionally,the ratio of mitral early filling wave peak velocity and early mitral annular peak velocity on septal side(E/e’ ratio),mitral early filling wave peak velocity(E wave),and left ventricular mass index(LVMI)were independent predictors of the diastolic EL;whereas systolic blood pressure(SBP)and LVMI were independent predictors of the systolic EL.Conclusions: Left ventricular EL was a useful echocardiographic parameter to evaluate the impaired intracardiac blood flow efficiency in patients with stages 1-3 CKD.Hypertension was a crucial contributor for intracardiac blood flow abnormality.This study might provide valuable clinical data to discern cardiac dysfunction and reduce the cardiovascular risk in early-stage CKD.Part two: Analysis of Left Ventricular Vortex in Patients with Stage 1-3 Chronic Kidney Disease using Vector Flow MappingObjective: Patients with stage1-3 CKD are often accompanied by unexpected heart disease,however,the intracardiac blood flow status in such patients have not yet been studied.Vortex is the important form that blood flowing in the heart cavity.We aimed to quantitatively analyze the left ventricular vortex in patients with stage1-3 CKD and pay a special focus on those patients with elevated blood pressure.Methods: Forty-eight patients with stages 1-3 CKD and Forty-one ageand gender-matched healthy volunteers were recruited.(The study population is the same as the first part).Vortex area(AV1)and circulation(CV1)during slow filling period,vortex area(AV2)and circulation(CV2)during isovolumetric contraction period,and the time ratio of vortex to cardiac cycle(RT)were studied between patients with early CKD and control group.CKD patients were further divided into two subgroups: a subgroup with no hypertension(N-HTN)and a subgroup with hypertension(H-HTN).The date about vortex were compared between the subgroups.Correlation and stepwise multiple regression analysis were used to explore the potential independent predictors of vortex parameters.Results: Compared with the control group,AV2 and CV2 were increased in patients with stage 1-3 CKD.Compared with N-HTN group,AV1,CV1,AV2,CV2 and RT were all increased in H-HTN group(all P < 0.05).Doppler parameters,cardiac configuration parameters and blood pressure were related with vortex and may be the influencing factors of vortex.Conclusion: The blood status in ventricle was changed in the patients with early CKD,and the elevated blood pressure was a crucial contributor for left ventricular blood flow abnormality.vortex parameters might be a novel parameter to discern preclinical cardiovascular disorders of early CKD patients in terms of fluid mechanics and provide a new imaging evidence for the strict control of blood pressure in early CKD patients.