Cardiac output and associated left ventricular hypertrophy in pediatric chronic kidney disease

Cardiac index: A superior parameter of cardiac function than left ventricular ejection fraction in risk stratification of hypertrophic cardiomyopathy

BACKGROUND

An appropriate indicator of cardiac function in the risk stratification of hypertrophic cardiomyopathy (HCM) patients is urgently needed. Cardiac index that reflects cardiac pumping function may be suitable.

OBJECTIVE

The purpose of this study was to investigate the clinical significance of reduced cardiac index in HCM patients.

METHODS

A total of 927 HCM patients were enrolled. The primary endpoint was cardiovascular death. The secondary endpoints were sudden cardiac death (SCD) and all-cause death. Combination models were constructed by adding reduced cardiac index and reduced left ventricular ejection fraction (LVEF) to the HCM risk-SCD model. Predictive accuracy was determined by C-statistics.

RESULTS

Reduced cardiac index was defined as cardiac index ≤2.42 L/min/m². During median follow-up of 4.3 years, 51 patients reached the endpoint. Reduced cardiac index independently increased the risk of cardiovascular death (adjusted hazard ratio [aHR] 2.976; P = .007), SCD (aHR 6.385; P = .001), and all-cause death (aHR 2.428; P = .010). By adding reduced cardiac index to the HCM risk-SCD model, the model C-statistic increased from 0.691 to 0.762, with an integrated discrimination improvement of 0.021 (P = .018) and a net reclassification improvement of 0.560 (P = .007). The addition of reduced LVEF failed to improve the original model. Better predictive accuracy for all endpoints was also indicated in reduced cardiac index than in reduced LVEF.

CONCLUSION

Reduced cardiac index is an independent predictor of poor prognoses in HCM patients. Combining reduced cardiac index rather than reduced LVEF improved the HCM risk-SCD stratification strategy. The reduced cardiac index showed better predictive accuracy than reduced LVEF for all endpoints.

Cardiac Abnormalities in Children with Pre-Dialysis Chronic Kidney Disease in a Resource-Limited Setting: A Cross-Sectional Observational Study

BACKGROUND

Cardiovascular disease is the leading cause of morbidity and mortality in children with chronic kidney disease (CKD). We aim to estimate the prevalence of cardiac abnormalities in children up to age 16 years with CKD and their association with various risk factors.

METHODS

This cross-sectional observational study was conducted on 107 CKD children. We assessed the systolic and diastolic function using 2D echocardiographic evaluation and M-mode measurements of the left ventricle (LV) indexed for BSA and z-scores were calculated. Results were compared with age, sex, stage of CKD, anaemia, estimated glomerular filtration rate (eGFR) and various laboratory parameters.

RESULTS

LV diastolic dysfunction was seen in 88%, followed by increased LV dimensions in 33.6%, LV systolic dysfunction in 16%, right ventricle systolic dysfunction in 11.2% while increased pulmonary artery (PA) systolic pressure was seen in 9.3% of cases. LV dimensions correlated directly with parathormone levels and inversely with eGFR, serum calcium and haemoglobin levels. Left ventricular hypertrophy correlated directly with parathormone while inversely with eGFR, serum calcium and haemoglobin. Ejection fraction directly correlated to eGFR and serum calcium while inversely related to parathormone. Left PA pressure directly correlated with age and inversely with eGFR. Right ventricular systolic function assessed by tricuspid annular plane systolic excursion correlated inversely with haemoglobin.

CONCLUSION

LV diastolic dysfunction and increased LV dimensions were the most common cardiac abnormality in children with CKD. LV dimensions correlated directly with parathormone levels and inversely with eGFR, serum calcium and haemoglobin. Diastolic dysfunction positively correlated with serum creatinine and parathormone levels.

Left-ventricular diastolic dysfunction in Korean children with chronic kidney disease: data from the KNOW-Ped CKD study

Background

Cardiovascular disease (CVD) is the most common cause of mortality in pediatric chronic kidney disease (CKD) patients. Left ventricular (LV) hypertrophy (LVH) is associated with LV diastolic dysfunction (LVDD) development and is used as an early marker of CVD in pediatric CKD. This study aimed to assess the prevalence and risk factors of LVDD and the association between LVH and LVDD in Korean pediatric CKD patients.

Methods

Data were collected using the baseline data of the Korean cohort study for outcome in patients with pediatric chronic kidney disease, a nationwide, 10-year, prospective, observational cohort study of pediatric CKD. A total of 244 patients were included in the final analysis. Two-dimensional echocardiography and tissue Doppler images were used to evaluate LVH and LVDD. LVH was defined as an LV mass index (LVMI) ≥38 g/m^2.7 and LV-wall thickness z-score > 1.64. LVDD was defined as a mitral peak velocity of early filling to early diastolic mitral annular velocity (E/E’) > 14. Univariate and multivariate logistic regression analyses were performed to evaluate risk factors of LVDD.

Results

In this study, the male-to-female ratio was 2.2 (168:76) and median age was 11.2 years. The average estimated glomerular filtration rate was 57.4 ml/min/1.73 m², and no patients received renal replacement therapy. The mean value of LVMI and E/E’ was 37.0 g/m^2.7 and 7.4, respectively. The prevalence of LVH was 40.1 and 17.4% by LVMI ≥38 g/m^2.7 and LV-wall thickness z-score, respectively. The prevalence of LVDD was 4.5%, and patients with LVH showed greater risk of LVDD (odds ratio 7.3, p = 0.012). In the univariate analysis, young age, low hemoglobin level, higher LVMI, and higher LV-wall thickness z-score were associated with LVDD. In the multivariate analysis, young age, low hemoglobin level, and higher LV-wall thickness z-score were independently associated with LVDD.

Conclusion

This study shows that LVH patients have a greater risk of LVDD and that anemia is the only modifiable risk factor for LVDD in Korean pediatric CKD patients.

Contribution of the Renal Nerves to Hypertension in a Rabbit Model of Chronic Kidney Disease

Overactivity of the sympathetic nervous system and high blood pressure are implicated in the development and progression of chronic kidney disease (CKD) and independently predict cardiovascular events in end-stage renal disease. To assess the role of renal nerves, we determined whether renal denervation (RDN) altered the hypertension and sympathoexcitation associated with a rabbit model of CKD. The model involves glomerular layer lesioning and uninephrectomy, resulting in renal function reduced by one-third and diuresis. After 3-week CKD, blood pressure was 13±2 mm Hg higher than at baseline (P<0.001), and compared with sham control rabbits, renal sympathetic nerve activity was 1.2±0.5 normalized units greater (P=0.01). The depressor response to ganglion blockade was also +8.0±3 mm Hg greater, but total norepinephrine spillover was 8.7±3.7 ng/min lower (bothP<0.05). RDN CKD rabbits only increased blood pressure by 8.0±1.5 mm Hg. Renal sympathetic activity, the response to ganglion blockade and diuresis were similar to sham denervated rabbits (non-CKD). CKD rabbits had intact renal sympathetic baroreflex gain and range, as well as normal sympathetic responses to airjet stress. However, hypoxia-induced sympathoexcitation was reduced by −9±0.4 normalized units. RDN did not alter the sympathetic response to hypoxia or airjet stress. CKD increased oxidative stress markers Nox5 and MCP-1 (monocyte chemoattractant protein-1) in the kidney, but RDN had no effect on these measures. Thus, RDN is an effective treatment for hypertension in this model of CKD without further impairing renal function or altering the normal sympathetic reflex responses to various environmental stimuli.

Interleukin 18 as a new inflammatory mediator in left ventricular hypertrophy in children with end-stage renal disease

Left ventricular hypertrophy (LVH) represents an important determinant of increased cardiovascular morbidity and mortality (CV) in end-stage renal disease (ESRD) patients. The role of inflammatory markers in pathogenesis of LVH in children with ESRD is not fully described. The aim of this study is to evaluate relation of some inflammatory markers [as hs C-reactive protein (hsCRP) and interleukin (IL) 18] with LVH in children with ESRD on regular hemodialysis (HD). This is a cross-sectional study performed on 50 children on regular HD. Demographic data were recorded. Echocardiography was performed at baseline to determine those with LVH. Biochemical parameters: hemoglobin (HB), hsCRP, IL 18, phosphorus, calcium, serum albumin, and lipid profile were evaluated and correlated with LVH. Data were analyzed using Student's t-test, and logistic regression to determine the relationship between LVH and other variables. LVH was present in 33 (66%) participants. Mean left ventricular mass index was 56.88 ± 22.23 g/m.^2.7 Concentric remodeling, concentric hypertrophy, and eccentric hypertrophy were present in 4%, 22%, and 44% of the participants. In univariate analysis, children with LVH had significantly lower levels of HB and serum albumin but higher levels of hsCRP, and IL 18 compared to those without LVH. On multivariate analysis: only hsCRP, and IL 18 were significantly associated with LVH. This study shows that elevated hsCRP and IL-18 are independent determinants of LVH in HD children. Understanding the role of inflammatory molecules in the pathogenesis of LVH in ESRD is important for prediction of high-risk group and implementation of targeted anti-inflammatory therapies.

Cardiovascular Disease in Children and Adolescents With Chronic Kidney Disease

The lifespan of children with advanced chronic kidney disease (CKD), although improved over the past 2 decades, remains low compared with the general pediatric population. Similar to adults with CKD, cardiovascular disease accounts for a majority of deaths in children with CKD because these patients have a high prevalence of traditional and uremia-related risk factors for cardiovascular disease. The cardiovascular alterations that cause these terminal events begin early in pediatric CKD. Initially, these act to maintain hemodynamic homeostasis. However, as the disease progresses, these modifications are unable to sustain cardiovascular function in the long term, leading to left ventricular failure, depressed cardiorespiratory fitness, and sudden death. In this review, we discuss the prevalence of the risk factors associated with cardiovascular disease in pediatric patients with CKD, the pathophysiology that stimulates these changes, the cardiac and vascular adaptations that occur in these patients, and management of the cardiovascular risk in these patients.

Influence of the Method of Definition on the Prevalence of Left-Ventricular Hypertrophy in Children with Chronic Kidney Disease: Data from the Know-Ped CKD Study

BACKGROUND/AIMS

Children with chronic kidney disease (CKD) have a high risk of cardiovascular disease. Left-ventricular (LV) hypertrophy (LVH) is an early marker of cardiovascular disease in pediatric CKD, and the prevalence of LVH in pediatric CKD is approximately 20-30% in pre-dialysis CKD patients. However, there is no consensus on the ideal method of defining LVH in pediatric CKD patients. Previous studies have typically used the LV mass index (LVMI), which is calculated as LV mass in grams divided by height in meters to the 2.7th power ≥ 38 g/m2.7, to diagnose LVH in children with CKD. Recently, age-specific reference values for LVMI ≥ 95th percentile and LV wall-thickness z-score > 1.64 in children were addressed. The aim of this study was to assess the prevalence and contributing factors of LVH in pediatric CKD patients according to each measurement and evaluate the concordance between each measurement.

METHODS

We used the baseline data of the KoreaN cohort study for Outcome in patients With Pediatric Chronic Kidney Disease (KNOW-Ped CKD), which is a nationwide, 10-year, prospective, observational cohort study of pediatric CKD. A total of 469 patients were enrolled, and 458 patients were included in the final analysis. Univariate and multiple logistic regression analysis were performed to evaluate the association of the variables with LVH. Kappa statistics were used to analyze the concordance.

RESULTS

According to an LVH diagnosis of LVMI ≥ 38 g/m2.7, 188 patients (41.0%) were diagnosed with LVH, and the prevalence of LVH was high in younger patients (< 2 years of age). Using the age-specific reference values, 116 patients (25.3%) were diagnosed with LVH, and there was no difference in the prevalence of LVH according to age. Thirty-one patients (6.8%) were diagnosed with LVH using an LV wall-thickness z-score > 1.64. There is poor concordance between the diagnosis of LVH using the LV wall-thickness z-score and the LVMI method.

CONCLUSIONS

The results of this study show that there is poor concordance between the diagnosis of LVH using the wall-thickness z-score and the LVMI2.7 criteria. Further investigation is needed to estimate the correlation between LVH and cardiac dysfunction and to find a better method for defining LVH in the pediatric CKD cohort and thereby predicting cardiac dysfunction.

Magnetic resonance tissue phase mapping demonstrates altered left ventricular diastolic function in children with chronic kidney disease

BACKGROUND

Echocardiographic examinations have revealed functional cardiac abnormalities in children with chronic kidney disease.

OBJECTIVE

To assess the feasibility of MRI tissue phase mapping in children and to assess regional left ventricular wall movements in children with chronic kidney disease.

MATERIALS AND METHODS

Twenty pediatric patients with chronic kidney disease (before or after renal transplantation) and 12 healthy controls underwent tissue phase mapping (TPM) to quantify regional left ventricular function through myocardial long (Vz) and short-axis (Vr) velocities at all 3 levels of the left ventricle.

RESULTS

Patients and controls (age: 8 years-20 years) were matched for age, height, weight, gender and heart rate. Patients had higher systolic blood pressure. No patient had left ventricular hypertrophy on MRI or diastolic dysfunction on echocardiography. Fifteen patients underwent tissue Doppler echocardiography, with normal z-scores for mitral early diastolic (V_E), late diastolic (V_A) and peak systolic (V_S) velocities. Throughout all left ventricular levels, peak diastolic Vz and Vr (cm/s) were reduced in patients: Vz_base -10.6 ± 1.9 vs. -13.4 ± 2.0 (P < 0.0003), Vz_mid -7.8 ± 1.6 vs. -11 ± 1.5 (P < 0.0001), Vz_apex -3.8 ± 1.6 vs. -5.3 ± 1.6 (P = 0.01), Vr_base -4.2 ± 0.8 vs. -4.9 ± 0.7 (P = 0.01), Vr_mid -4.7 ± 0.7 vs. -5.4 ± 0.7 (P = 0.01), Vr_apex -4.7 ± 1.4 vs. -5.6 ± 1.1 (P = 0.05).

CONCLUSION

Tissue phase mapping is feasible in children and adolescents. Children with chronic kidney disease show significantly reduced peak diastolic long- and short-axis left ventricular wall velocities, reflecting impaired early diastolic filling. Thus, tissue phase mapping detects chronic kidney disease-related functional myocardial changes before overt left ventricular hypertrophy or echocardiographic diastolic dysfunction occurs.

Left ventricular mass and systolic function in children with chronic kidney disease-comparing echocardiography with cardiac magnetic resonance imaging

BACKGROUND

Increased left ventricular mass (LVM) is an important risk marker of uremic cardiovascular disease. Calculation of LVM by echocardiography (Echo) relies on geometric assumptions and in adults on hemodialysis overestimates LVM compared to cardiac magnetic resonance (CMR). We compare both techniques in children with chronic kidney disease (CKD).

METHODS

Concurrent Echo and CMR was performed in 25 children with CKD (14 after kidney transplantation) aged 8-17 years.

RESULTS

Compared to normal children, CMR-LVM was increased (standard deviation score (SDS) 0.39 ± 0.8 (p = 0.03)), stroke volume and cardiac output decreased (SDS -1.76 ± 1.1, p = 0.002 and -1.11 ± 2.0, p = 0.001). CMR-LVM index but not Echo-LVMI correlated to future glomerular filtration rate (GFR) decline (r = -0.52, p = 0.01). Mean Echo-LVM was higher than CMR-LVM (117 ± 40 vs. 89 ± 29 g, p < 0.0001), with wide limits of agreement (-6.2 to 62.8 g). The Echo-CMR LVM difference increased with higher Echo-LVMI (r = 0.77, p < 0.0001). Agreement of classifying left ventricular hypertrophy was poor with Cohen's kappa of 0.08. Mean Echo and CMR-ejection fraction differed by 1.42% with wide limits of agreement (-12.6 to 15.4%).

CONCLUSIONS

Echo overestimates LVM compared to CMR, especially at higher LVM. Despite this, CMR confirms increased LVM in children with CKD. Only CMR-LVMI but not Echo-LVMI correlated to future GFR decline.

Association between cardiovascular autonomic neuropathy and left ventricular dysfunction: DCCT/EDIC study (Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications)

OBJECTIVES

The goal of these studies was to determine the association between cardiovascular autonomic neuropathy (CAN) and indices of left ventricle (LV) structure and function in patients with type 1 diabetes (T1DM) in the DCCT/EDIC (Diabetes Control and Complications Trial /Epidemiology of Diabetes Interventions and Complications) study.

BACKGROUND

The pathophysiology of LV dysfunction in T1DM remains unclear, especially when the LV ejection fraction (EF) is preserved. Whether CAN is associated with LV dysfunction is unclear.

METHODS

Indices of LV structure and function were obtained by cardiac magnetic resonance imaging (CMRI). CAN was assessed by cardiovascular reflex testing (R-R response to paced breathing, Valsalva ratio, and blood pressure response to standing). Analyses were performed in 966 DCCT/EDIC participants with valid CMRI and CAN data (mean age 51 years, 52% men, mean diabetes duration 29 years, and mean glycosylated hemoglobin 7.9%).

RESULTS

Systolic function (EF, end-systolic and end-diastolic volumes, stroke volumes) was not different in 371 subjects with CAN compared with 595 subjects without CAN. In multiple-adjusted analyses, participants with either abnormal R-R variation or a composite of abnormal R-R variation, abnormal Valsalva ratio, and postural blood pressure changes had significantly higher LV mass, mass-to-volume-ratio, and cardiac output compared with those with normal tests (p < 0.0001 for all). After further adjustment for traditional cardiovascular risk factors, subjects with abnormal R-R variation had higher LV mass and cardiac output compared with those with a normal R-R variation (p < 0.05).

CONCLUSIONS

In this large cohort of patients with T1DM, CAN is associated with increased LV mass and concentric remodeling as assessed by CMRI independent of age, sex, and other factors. (Diabetes Control and Complications Trial [DCCT]; NCT00360815) (Epidemiology of Diabetes Interventions and Complications [EDIC]; NCT00360893).

Cardiovascular risk assessment in children following kidney transplantation

CV diseases are the leading cause of death among patients with ESRD. RTX decreases the CV risk; however, it still remains definitely higher than that of the general population. Large multicenter and longitudinal studies are difficult to perform and hard end-points of CV events are usually missing among pediatric population. Thus, appropriate estimation of CV risk is of crucial importance to define the potential hazards and to evaluate the effect of treatments aimed to reduce the risk. A number of validated non-invasive methods are available to assess the extent of CV damage in adults, such as calcification scores, cIMT, aPWV, 24-h ABPM, AASI, and HRV; however, they need adaptation, standardization, and validation in pediatric studies. cIMT and PWV are the most promising methods, as pediatric normative values are already present. The up-to-date treatment of ESRD aims not only to save life, but to offer the patient a life expectancy approaching that of the healthy population and to ensure a reasonable quality of life.

Defining left ventricular hypertrophy in children on peritoneal dialysis

BACKGROUND AND OBJECTIVES

Left ventricular hypertrophy (LVH) is an important end point of dialysis-associated cardiovascular disease. The objective of this study was to evaluate the effect of different pediatric reference systems on the estimated prevalence of LVH in children on chronic peritoneal dialysis (CPD).

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Echocardiographic studies in 507 pediatric CPD patients from neonatal age to 19 years were collected in 55 pediatric dialysis units around the globe. We compared the prevalence of LVH on the basis of the traditional cutoff of left ventricular mass (LVM) index (>38.5 g/m(2.7)) with three novel definitions of LVH that were recently established in healthy pediatric cohorts.

RESULTS

Application of the new reference systems eliminated the apparently increased prevalence of LVH in young children obtained by the traditional fixed LVM index cutoff currently still recommended by consensus guidelines. However, substantial differences of LVM distribution between the new reference charts resulted in a marked discrepancy in estimated LVH prevalence ranging between 27.4% and 51.7%.

CONCLUSIONS

Although our understanding of the anthropometric determinants of heart size during childhood is improving, more consistent normative echocardiographic data from large populations of healthy children are required for cardiovascular diagnostics and research.

Acute reversible changes of brachial-ankle pulse wave velocity in children with acute poststreptococcal glomerulonephritis

Acute poststreptococcal glomerulonephritis (APSGN) is the most common form of postinfectious nephritis worldwide. The relationship between inflammation and arterial stiffness has been described elsewhere, but there have been no studies that have analyzed the association between arterial compliance and APSGN. The aim of this study is to assess brachial-ankle pulse wave velocity (baPWV) in pediatric patients with APSGN, and the value of baPWV in predicting the outcome. We evaluated 16 children diagnosed with APSGN, 11 children with acute pyelonephritis (APN), and 25 healthy individuals in our hospital. The baPWV of all candidates was measured. In addition, follow-up of the APSGN group was conducted for baPWV, blood pressure and biochemical parameters. Significantly increased baPWV was observed in the APSGN group at initial diagnosis (P<0.001), in comparison with the APN group and healthy controls. Of these, 13 patients received sequential measurement of baPWV. Overwhelmingly, baPWV was rapidly normalized in 11 patients, whereas 2 boys presented with persistently higher baPWV. During the follow-up period of 2-3 years, both had consistency of proteinuria, and consequently, they progressed to either chronic renal insufficiency or end-stage renal disease (ESRD). In conclusion, the results demonstrate that APSGN involves not only the kidney, but also the arteries outside the kidney. Acute arterial stiffness might persist in patients who do not recover, but develop chronic kidney disease (CKD).

Cardiovascular disease in CKD in children: update on risk factors, risk assessment, and management

In young adults with onset of chronic kidney disease in childhood, cardiovascular disease is the most common cause of death. The likely reason for increased cardiovascular disease in these patients is a high prevalence of traditional and uremia-related cardiovascular disease risk factors during childhood chronic kidney disease. Early markers of cardiomyopathy, such as left ventricular hypertrophy and left ventricular dysfunction, and early markers of atherosclerosis, such as increased carotid artery intima-media thickness, carotid arterial wall stiffness, and coronary artery calcification, frequently are found in this patient population. The purpose of this review is to provide an update of recent advances in the understanding and management of cardiovascular disease risks in this population.