Echocardiographic abnormalities in dialysis patients with normal ejection fraction

Atrial and Ventricular Structural and Functional Alterations in Obese Children

Background and objectives: Childhood obesity has reached epidemic levels in the world. Obesity in children is defined as a body mass index (BMI) equal to or above the 95th percentile for age and sex. The aim of this study was to determine early changes in cardiac structure and function in obese children by comparing them with their nonobese peers, using echocardiography methods. Materials and methods: The study enrolled 35 obese and 37 age-matched nonobese children. Standardized 2-dimensional (2D), pulsed wave tissue Doppler, and 2D speckle tracking echocardiography were performed. The z-score BMI and lipid metabolism were assessed in all children. Results: Obese children (aged 13.51 ± 2.15 years; 20 boys; BMI z-score of 0.88 ± 0.63) were characterized by enlarged ventricular and atrial volumes, a thicker left ventricular posterior wall, and increased left ventricular mass. Decreased LV and RV systolic and diastolic function was found in obese children. Atrial peak negative (contraction) strain (−2.05% ± 2.17% vs. −4.87% ± 2.97%, p < 0.001), LV and RV global longitudinal strain (−13.3% ± 2.88% vs. −16.87% ± 3.39%; −12.51% ± 10.09% vs. −21.51% ± 7.42%, p < 0.001), and LV global circumferential strain (−17.0 ± 2.7% vs. −19.5 ± 2.9%, p < 0.001) were reduced in obese children. LV torsion (17.94° ± 2.07° vs. 12.45° ± 3.94°, p < 0.001) and normalized torsion (2.49 ± 0.4°/cm vs. 1.86 ± 0.61°/cm, p = 0.001) were greater in obese than nonobese children. A significant inverse correlation was found between LV and RV global longitudinal strain and BMI (r = −0.526, p < 0.01; r = −0.434, p < 0.01) and total cholesterol (r = −0.417, p < 0.01). Multivariate analysis revealed that the BMI z-score was independently related to LV and RV global longitudinal strain as well as LV circumferential and radial strain. Conclusion: 2D speckle tracking echocardiography is beneficial in the early detection of regional LV systolic and diastolic dysfunctions, with preserved ejection fraction as well as additional RV and atrial involvement, in obese children. Obesity may negatively influence atrial and ventricular function, as measured by 2D speckle tracking echocardiography. Obese children, though they are apparently healthy, may have subclinical myocardial dysfunction.

Natural History of Clinical, Laboratory, and Echocardiographic Parameters of a Primary Hyperoxaluria Cohort on Long Term Hemodialysis

Background: Primary hyperoxaluria type 1 (PH1) is a rare monogenic disorder characterized by excessive hepatic production of oxalate leading to recurrent nephrolithiasis, nephrocalcinosis, and progressive kidney damage, often requiring renal replacement therapy (RRT). Though systemic oxalate deposition is well-known, the natural history of PH1 during RRT has not been systematically described. In this study, we describe the clinical, laboratory, and echocardiographic features of a cohort of PH1 patients on RRT.

Methods: Patients with PH1 enrolled in the Rare Kidney Stone Consortium PH Registry who progressed to require RRT, had ≥2 plasma oxalate (pOx) measurements 3–36 months after start of RRT, and at least one pair of pOx measurements between 6 and 18 months apart were retrospectively analyzed. Clinical, echocardiographic, and laboratory results were obtained from the Registry.

Results: The 17 PH1 patients in our cohort had a mean total HD hours/week of 17.4 (SD 7.9; range 7.5–36) and a range of age of RRT start of 0.2–75.9 years. The average change in plasma oxalate (pOx) over time on RRT was −0.74 [−2.9, 1.4] μmol/L/month with the mean pOx never declining below 50 μmol/L. Over time on RRT, oxalosis progressively developed in multiple organ systems. Echocardiography performed on 13 subjects showed worsening of left ventricular global longitudinal strain correlated with pOx (p < 0.05).

Conclusions: Even when a cohort of PH1 patients were treated with intensified RRT, their predialysis pOx remained above target and they developed increasing evidence of oxalosis. Echocardiographic data suggest that cardiac dysfunction could be related to elevated pOx and may worsen over time.

Assessment of cardiac structure and function in kidney failure: understanding echocardiography and magnetic resonance imaging for the nephrologist

Cardiovascular disease is the leading cause of death in patients with kidney failure or on chronic dialysis. Patients on chronic dialysis have a 10- to 50-fold increased risk of sudden cardiac death compared to patients with normal kidney function. Adverse changes in cardiac structure and function may not manifest with clinical symptoms in patients with kidney failure and, therefore, pose a challenge in identifying cardiac dysfunction early. Fortunately, there are multi-modality cardiac imaging techniques available, including echocardiography and cardiac magnetic resonance imaging, that can help our understanding of the pathophysiology of cardiac dysfunction in kidney failure. This review describes the benefits and limitations of these two commonly available cardiac imaging modalities to assess cardiac structure and function, thereby aiding nephrologists in choosing the most appropriate investigative tool based on individual clinical circumstances. For the purposes of this review, cardiac imaging for detection of coronary artery disease has been omitted.

Changes of Left and Right Ventricle Mechanics and Function in Patients with End-Stage Renal Disease Undergoing Haemodialysis

Background and objectives: Chronic kidney disease (CKD) increases the risk of cardiovascular diseases even in its early stages and is associated with structural and functional cardiac abnormalities. The aim of this study was to use speckle-tracking echocardiography (STE) to evaluate left and right ventricle mechanics and function, markers of subclinical dysfunction in patients with end-stage renal disease (ESRD) undergoing haemodialysis. Methods: Patients with ESRD undergoing regular haemodialysis and with preserved left ventricle (LV) ejection fraction (EF) (n = 38) were enrolled in this retrospective study. The control group consisted of 32 age-matched persons with normal kidney function (glomerular filtration rate (GFR) >90 mL/min/1.73 m² according to Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI)). Conventional 2D echocardiography and STE were performed in all patients. Results: 70 individuals, 31 (44.29%) males and 39 (55.71%) females, were included in the study. There were no significant differences in age, sex and body surface area between the groups. LV end diastolic diameter did not differ between the groups, while LV myocardial mass index was higher in the group of patients on haemodialysis (111.64 ± 27.99 versus 84.21 ± 16.99, p < 0.001) and LV diastolic dysfunction (LVDD) was found in 31 (81.6%) patients of this group. LV global longitudinal strain (GLS) (-22.43 ± 2.71 versus -24.73 ± 2.03, p < 0.001) and LV global circumferential strain (GCS) at the mitral valve and papillary muscles levels (-18.73 ± 3.49 versus -21.67 ± 2.22, p < 0.001; -18.64 ± 2.75 versus -20.42 ± 2.38, p = 0.005, respectively) were significantly lower in haemodialysis group patients. The parameters of the right ventricle (RV) free wall longitudinal function including RV GLS (-22.63 ± 3.04 versus -25.45 ± 2.48, p < 0.001), were reduced in haemodialysis patients compared with the controls. However, RV fractional area change (FAC) did not differ between the groups (p = 0.19). Conclusion: Patients with ESRD and preserved LV ejection fraction undergoing haemodialysis had a higher prevalence of LVDD and impaired LV longitudinal and circumferential deformation indices, as well as reduced RV longitudinal function and deformation parameters compared with the age-matched healthy controls. STE helps to detect subclinical LV and RV dysfunction in chronic haemodialysis patients.

Hepcidin serum levels and resistance to recombinant human erythropoietin therapy in hemodialysis patients

OBJECTIVE

The aim of this study was to analyze the factors that are associated with the response to erythropoiesis-stimulating agents (ESAs) and its association with hospitalization and mortality rates; to evaluate the serum hepcidin level and its associations with iron profile, inflammatory markers, ESA responsiveness, and mortality; and to determine independent factors affecting ERI and hepcidin.

MATERIALS AND METHODS

To evaluate a dose-response effect of ESAs we used the erythropoietin resistance index (ERI). Patients were stratified in two groups: nonresponders and responders (ERI>15, n=20, and ERI ≤15U/kg/week/g per 100mL, n=153, respectively). Hematological data, hepcidin levels, iron parameters, inflammatory markers, hospitalization and mortality rates were compared between the groups. Multiple regression analysis was used to determine independent factors affecting ERI and hepcidin.

RESULTS

C-reactive protein (CRP) (β=0.078, P=0.007), albumin (β=-0.436, P=0.004), body mass index (β=-0.374, P<0.001), and hospitalization rate per year (β=3.017, P<0.001) were found to be significant determinants of ERI in maintenance hemodialysis (MHD) patients. Inadequate dialysis was associated with higher ERI. Patients with concomitant oncological diseases had higher ERI (31.2±12.4 vs 9.7±8.1U/kg/week/g per 100mL, P=0.002). The hepcidin level was 158.51±162.57 and 120.65±67.28ng/mL in nonresponders and responders, respectively (P=0.33). Hepcidin correlated directly with ERI, dose of ESAs, ferritin and inversely with Hb, transferrin saturation, and albumin. ERI (β=4.869, P=0.002) and ferritin (β=0.242, P=0.003) were found to be significant determinants of hepcidin in MHD patients. The hospitalization rate per year was 2.35±1.8 and 1.04±1.04 in nonresponders and responders, respectively (P=0.011). The mean length of one hospitalization was 25.12±21.26 and 10.82±17.25 days, respectively (P=0.012). Death occurred in 30% of the patients from the responders' group and in 50% from the nonresponders' group (P=0.289). The mean hepcidin concentration of patients who died was 141.9±129.62ng/mL and who survived, 132.98±109.27ng/mL (P=0.797).

CONCLUSIONS

CRP, albumin, BMI, and hospitalization rate per year were found to be significant determinants of ERI in MHD patients. Inadequate dialysis was associated with higher epoetin requirements. There were no difference in patient mortality by ERI, but a significant difference in hospitalization rates and mean length of one hospitalization was revealed. A significant positive relation between hepcidin and ERI was revealed. ERI and ferritin were found to be significant determinants of hepcidin in MHD patients. Hepcidin was not related to mortality.

Echocardiography in hemodialysis patients: uses and challenges

Patients with end-stage renal disease undergoing hemodialysis have high rates of morbidity and mortality. Cardiovascular disease accounts for almost half of this mortality, with the single most common cause being sudden cardiac death. Early detection of abnormalities in cardiac structure and function may be important to allow timely and appropriate cardiac interventions. Echocardiography is noninvasive cardiac imaging that is widely available and provides invaluable information on cardiac morphology and function. However, it has limitations. Echocardiography is operator dependent, and image quality can vary depending on the operator's experience and the patient's acoustic window. Hemodialysis patients undergo regular hemodynamic changes that also may affect echocardiographic findings. An understanding of the prognostic significance and interpretation of echocardiographic results in this setting is important for patient care. There are some emerging techniques in echocardiographic imaging that can provide more detailed and accurate information compared with conventional 2-dimensional echocardiography. Use of these novel tools may further our understanding of the pathophysiology of cardiac disease in patients with end-stage renal disease undergoing hemodialysis.