Quantitative Evaluation Of Cardiac Structure And Function In Patients With Chronic Kidney Disease By Echocardiography

Part Ⅰ:Longitudinal Changes of Cardiac Structure and Function in CKD: CASCADE StudyBackground:CKD is a global public health problem and a major risk factor for cardiovascular disease. However, little is known regarding the natural longitudinal changes in cardiac structure and function in CKD. We hypothesized that baseline CKD stage is associated with progressive worsening in cardiac structure and function.Methods:We conducted a prospective longitudinal study, recruiting 300 patients with stages 3-5 CKD from a major regional tertiary center and university teaching hospital in Hong Kong. Transthoracic echocardiography was performed at baseline and 1 year. Baseline CKD stages were studied in relation to natural longitudinal changes in echocardiographic and tissue Doppler imaging-derived parameters.Results:Over 1 year, the prevalence of left ventricular (LV) hypertrophy increased from40.3% to 48.9%, median left atrial volume index increased 4.8 (interquartile range [IQR],2.1,7.7) ml/m2 (P<0.001), peak systolic mitral annular velocity decreased 0.5 (IQR,21.5,0.5) cm/s (P<0.001), early diastolic mitral annular velocity decreased 0.5 (IQR,21.5,0.5) cm/s (P<0.001), and eGFR declined 2.0 (IQR,25.0,0.0)ml/min per 1.73m2. CKD stages 4 and 5 were associated with more baseline abnormalities in cardiac structure and function and predicted greater longitudinal progression in LV mass index (odds ratio [OR],3.02; 95% confidence interval [95% CI],1.39 to 6.58), volume index (OR,2.58; 95% CI,1.18 to 5.62), and left atrial volume index (OR,2.61; 95% CI,1.20 to 5.69) and worse diastolic dysfunction grade (OR,3.17; 95% CI,1.16 to 8.69) compared with stage 3 a in the fully adjusted analysis.Conclusion:This prospective longitudinal study demonstrated a significant deterioration in cardiac structure and systolic and diastolic function over 1 year in patients with stages 3-5 CKD. More advanced CKD at baseline may be associated with larger longitudinal increases in LV mass and volume and greater deterioration in diastolic function.Part Ⅱ:Subclinical Left Ventricular Systolic Dysfunction by Strain Imaging in Chronic Kidney Disease Subjects with Preserved Ejection Fraction:The Prospective CASCADE StudyBackground:Abnormal cardiac structure and function is frequently observed in chronic kidney disease (CKD) subjects and predicts an adverse clinical outcome. However, conventional echocardiography is not sensitive enough in detecting early deterioration in cardiac function.2D-speckle tracking echocardiography with strain analysis is a more precise and reproducible technique that enables a more accurate assessment of systolic function. This study aims to determine whether CKD subjects with preserved left ventricular ejection fraction (LVEF) may exhibit subclinical systolic dysfunction, detected using strain imaging and whether abnormalities in global strain parameters may be associated with the severity of kidney dysfunction in CKD.Methods:We conducted a prospective observational study in 273 stages 3-5 CKD subjects with preserved LVEF (defined as EF≥50%) and 65 age, and sex-matched healthy controls. All subjects underwent conventional echocardiography with strain imaging together with assessment of various clinical and biochemical parameters including estimated glomerular filtration rate [eGFR].Results:Overall, CKD subjects as a group showed lower systolic global longitudinal strain (GLS) [-20.1 ± 2.3 vs.-21.6 ± 2.4, P<0.001] and circumferential strain (CS) [-18.1 ± 2.8 vs.-19.4 ± 2.8, P=0.001] compared with controls. Furthermore, when stratifying into CKD stages 3a,3b,4 and 5, GLS (3a vs.3b vs.4&5 vs. control; P<0.001), CS (P= 0.006) and RS (P=0.012) showed significant deterioration with increasing severity of CKD stages and versus control subjects. However, patients with CKD4-5 only showed greater prevalence of abnormal GLS in multivariate regression after adjustment of relevant clinical and biochemical parameters (OR=8.12,95%CI[1.59,41.5], P=0.012).Conclusions:Strain imaging detects subclinical LV systolic dysfunction in CKD subjects with preserved LVEF. Furthermore, the degree of subclinical systolic dysfunction as denoted by GLS appeared to show an important and independent relationship with the severity of CKD. Strain imaging is a novel and more accurate imaging technique that allows earlier detection of subclinical cardiac functional abnormalities in CKD and may provide better cardiovascular risk stratification.Part Ⅲ:Relationship between Left Ventricular Systolic Function and Diastolic Function in Chronic Kidney Disease:Longitudinal CASCADE studyBackground:Systolic and diastolic dysfunction were associated in many chronic diseases. Although studies have showed there is subclinical systolic dysfunction apart from diastolic dysfunction in patients with chronic kidney disease (CKD), whether this kind of association remains in CKD is still under discussed. Moreover, left ventricular hypertrophy was demonstrated to be associated with systolic and diastolic dysfunction respectively in CKD. Thus, we aimed to detect the relationship between left ventricular systolic and diastolic function as well as the influence from left ventricular mass index (LVMI) in CKD.Methods:We conducted a prospective longitudinal study, recruiting 300 patients with stages 3-5 CKD from a major regional tertiary center and university teaching hospital in Hong Kong. Transthoracic echocardiography and speckle tracking analysis were performed at baseline and 1 year. Relationship between longitudinal systolic strain and diastolic function and the influence from LVMI were studied.Results:LVMI increased from basline104±32.7g/m2 to 110±34.0g/m2 in 1 year study (P <0.001). Ratio of peak early transmitral flow velocity to early diastolic mitral annular velocity (E/Em) aggravated from baseline 8.86 to 9.54 in 1 year (P<0.001). Global longitudinal strain (GLS) changed from -20.0% to-19.7%(P=0.01). Change slopes of E/Em and GLS were associated independently (Coefficient R=0.07,95% Confidence Interval [95%CI]0.003 to 0.14, P=0.042). After divided into tertiles of LVMI, this independent relationship only remained in high LVMI group.Conclusions:GLS was independently associated with E/Em in CKD patients. LVMI might be the main medium in this relationship. Early detection of increased LVMI may play an important part in improving the prognosis of cardiac function in CKD patients.