Left ventricular mass and cardiac function in a population of children with chronic kidney disease

Cardiac biomarkers in pediatric CKD-a prospective follow-up study

BACKGROUND

The N-terminal pro-B-type natriuretic peptide (NT-proBNP) and high-sensitive cardiac-specific troponin T (hs-cTnT) are associated with abnormal cardiac structure and function and an increased risk of cardiovascular death in chronic kidney disease (CKD) patients. There is limited knowledge about these cardiac markers in pediatric CKD patients.

METHODS

Longitudinal levels of NT-proBNP and hs-cTnT were analyzed in 48 pediatric patients, 22 with CKD (GFR range 8.8-68 mL/min/1.73 m²) and 26 transplanted patients (CKD-T; GFR range 30-99 mL/min/1.73 m²). Follow-up was scheduled after 1 and 3 years. Longitudinal patterns and associations to kidney function, cardiovascular risk markers, and echocardiographic parameters were assessed.

RESULTS

High NT-proBNP was present in 27% of CKD and 11% of CKD-T patients. Similarly 32% of CKD and 8% of CKD-T patients had elevated hs-cTnT levels. In longitudinal multivariate analyses, high log NT-proBNP was associated with low GFR (β =  - 0.01, p = 0.01) and elevated left ventricular mass index (LVMI; β = 0.02, p = 0.05). The strong association to LVMI remained when using GFR-adjusted NT-proBNP in similar analysis. Patients with left ventricular hypertrophy (LVH) also had higher NT-proBNP (235 [146-301] ng/L) than patients without LVH (86 [11-477] ng/L), p = 0.02. High hs-cTnT over-time was also associated with low GFR (β =  - 0.007, p = 0.01) and a low cc-TDI e´/a´, indicating a worse LV diastolic function (β =  - 0.09, p = 0.05). This association did not persist for GFR-adjusted hs-cTnT.

CONCLUSIONS

NT-proBNP and hs-cTnT are elevated in pediatric CKD and CKD-T patients. GFR-adjusted NT-proBNP was associated with longitudinal levels of elevated LVMI suggesting this might be a marker for early subclinical myocardial damage. A higher resolution version of the Graphical abstract is available as Supplementary information.

Maternal Factors in Pregnancy and Ethnicity Influence Childhood Adiposity, Cardiac Structure, and Function

IMPORTANCE

The links between maternal and offspring adiposity and metabolic status are well established. There is much less evidence for the impact of these relationships combined with ethnic background on cardiac structure and function in childhood.

OBJECTIVE

To test the hypothesis that ethnicity, maternal adiposity and glycemic status, and child adiposity affect cardiac structure and function.

DESIGN

A prospective cohort study.

SETTING

A single-center mother-child cohort study. The cohort is a subset of the international multi-center Hyperglycemia and Adverse Pregnancy Outcomes (HAPO) study.

PARTICIPANTS

This study included 101 healthy pre-pubertal British-born children [56 White Europeans (WEs) and 45 South Asians (SAs)] with a median age of 9.1 years, range 6.0-12.2 years, at the time of the investigation.

MAIN OUTCOMES AND MEASURES

Anthropometric and echocardiographic measurements were made on the cohort. Maternal pregnancy and birth data were available. Relationships between maternal parameters (BMI and glucose status), child adiposity, and echo measures were assessed.

RESULTS

Despite no ethnic difference in BMI SDS at a median age of 9.1 years, SA children exhibited higher levels of body fat than WE children (whole body, right arm, and truncal fat all p < 0.001). SA children also exhibited greater changes in weight and height SDS but not BMI SDS from birth than WE children. As expected, maternal BMI correlated with child BMI (r = 0.28; p = 0.006), and body fat measures (e.g., whole body fat r = 0.25; p = 0.03). Maternal fasting glucose levels were associated with child body fat measures (r = 0.22-0.28; p = 0.02-0.05). Left ventricular (LV) indices were not different between SA and WE children, but E/A and E'/A' (measures of diastolic function) were lower in SA when compared with WE children. LV indices correlated positively to BMI SDS and body fat markers only in SA children. Maternal fasting and 2-h glucose were negatively correlated with E'/A' in SA children (r = -0.53, p = 0.015, and r = -0.49, p = 0.023, respectively) but not in WE children.

CONCLUSION AND RELEVANCE

SA and WE children exhibit differences in adiposity and diastolic function at a median age of 9.1 years. Novel relationships between maternal glycemia, child adiposity, and cardiac structure and function, present only in SA children, were identified.

Assessments of left ventricular systolic and diastolic functions with tissue Doppler imaging and myocardial performance index in children with chronic kidney disease

BACKGROUND

This study aimed to document early left ventricular (LV) dysfunction in chronic kidney disease (CKD) using methods such as tissue Doppler imaging and the myocardial performance index (MPI).

METHODS

A total of 40 patients diagnosed with CKD (mean age, 10.1 ± 4.1 years) and 40 sex- and age-matched healthy controls (mean age, 9.6 ± 4.3 years) were examined. In the patient group, 20 patients had early stage (Stage 2-3) CKD and 20 patients had late-stage (stage 4-5) CKD, and 18 patients had hypertension.

RESULTS

The pulmonary artery systolic pressure (PAPs) and LV mass index (LVMI) were significantly higher in the patient group (P < 0.05). The LV septal and lateral margins of the mitral annulus E'/A' ratio, E/E' ratio and MPI results were significantly different between the groups (P < 0.05). The MPI scores were higher in late-stage CKD than in early stage CKD (P < 0.05). The E'/A' ratio was lower and the MPI was higher in the hypertensive CKD group compared with the normotensive CKD group (P < 0.05). The E/E' ratio was correlated positively with the LVMI, and the PAPs, and negatively with glomerular filtration rate, S' value, E'/A' ratio. The MPI was correlated positively with blood pressure, LVMI, PAPs, and the S value, and negatively with the E'/A' ratio.

CONCLUSIONS

The E'/A' ratio, the E/E' ratio, and the isovolumetric relaxation time measured by tissue Doppler imaging is highly accurate and easily applicable for detecting diastolic LV function, and the MPI is suitable for detecting both systolic and diastolic LV dysfunction. Their routine use may be useful in evaluating LV functions in children with CKD.

Changes in cardiac function after renal transplantation in children: Significance of pre-transplantation left ventricular hypertrophy

LVH is a significant risk factor for the development of cardiovascular morbidity. However, few studies have evaluated the changes in cardiac function that occur in pediatric patients with ESRD undergoing RTx. Therefore, we assessed the changes in parameters associated with LVH in children within the first year after RTx. We retrospectively evaluated patients aged < 18 years who underwent initial RTx from April 2014 to December 2016. The patients were divided into 2 groups according to the presence of LVH before RTx. Clinical, biochemical, and echocardiographic parameters including the LVMI before and 1 year after RTx were evaluated in both groups. Twenty-six patients were included in this study. Seven of the 26 patients had LVH before RTx. Among the echocardiographic parameters, the LVMI was significantly improved 1 year after RTx in the initial LVH group (57.79 ± 11.86 vs 42.20 ± 6.03 g/cm^2.7 , P = .018), while no change was observed in the initial non-LVH group (32.66 ± 7.52 vs 35.17 ± 12.86 g/cm^2.7 , P = .376). Improvement of the ejection fraction was also observed only in the initial LVH group (66.5% ± 5.3% vs 72.2% ± 5.2%, P = .042). Children who had LVH before RTx showed significant improvements in the LVMI and ejection fraction even within 1 year after RTx. To minimize aggravation of cardiac function, early RTx should be considered for patients with LVH.

Impaired Systolic and Diastolic Left Ventricular Function in Children with Chronic Kidney Disease - Results from the 4C Study

Children with chronic kidney disease suffer from excessive cardiovascular mortality and early alterations of the cardiovascular system. Tissue doppler imaging is a validated echocardiographic tool to assess early systolic and diastolic cardiac dysfunction. We hypothesized that tissue Doppler velocities would reveal reduced cardiac function in children with chronic kidney disease compared to healthy children. A standardized echocardiographic exam was performed in 128 patients of the Cardiovascular Comorbidity in Children with Chronic Kidney Disease (4C) Study aged 6–17 years with an estimated glomerular filtration rate (eGFR) below 60 ml/min/1.73 m². Tissue Doppler measurements included early (E’) and late (A’) diastolic and systolic (S’) velocity at the mitral and septal annulus of the left ventricle. Measured values were normalized to z-scores using published reference data. Predictors of E’/A’, E/E’, S’ and left ventricular mass index (LVMI) were assessed by multiple linear regression analyses. Tissue Doppler E’ was reduced and tissue Doppler A’ increased, resulting in a reduced tissue Doppler E’/A’ ratio (z-score −0.14, p < 0.0001) indicating reduced diastolic function compared to healthy children. Reduced tissue Doppler E’/A’ Z-Scores were independently associated with lower eGFR (p = 0.002) and increased systolic blood pressure (p = 0.02). While E/E’ Z-Scores were increased (Z-score 0.57, p < 0.0001), patients treated with pharmacological RAS blockade but not with other antihypertensive treatments had significantly lower E/E’ and higher E’/A’ Z-Scores. Systolic tissue Doppler velocities were significantly decreased (Z-score −0.24, p = 0.001) and inversely correlated with E/E’ Z-Scores (r = −0.41, p < 0.0001). LVMI was not associated with systolic or diastolic tissue Doppler velocities. Concentric left ventricular hypertrophy showed a tendency to lower S’ in multivariate analysis (p = 0.13) but no association to diastolic function. Concentric left ventricular geometry was significantly associated with lower midwall fractional shortening. In summary, systolic and diastolic function assessed by tissue Doppler is impaired. eGFR, systolic blood pressure and the type of antihypertensive medications are significant predictors of diastolic function in children with CKD. Left ventricular morphology is largely independent of tissue Doppler velocities. Tissue Doppler velocities provide sensitive information about early left ventricular dysfunction in this population.

A comprehensive characterization of myocardial and vascular phenotype in pediatric chronic kidney disease using cardiovascular magnetic resonance imaging

BACKGROUND

Children with chronic kidney disease (CKD) have increased cardiovascular mortality. Identifying high-risk children who may benefit from further therapeutic intervention is difficult as cardiovascular abnormalities are subtle. Although transthoracic echocardiography may be used to detect sub-clinical abnormalities, it has well-known problems with reproducibility that limit its ability to accurately detect these changes. Cardiovascular magnetic resonance (CMR) is the reference standard method for assessing blood flow, cardiac structure and function. Furthermore, recent innovations enable the assessment of radial and longitudinal myocardial velocity, such that detection of sub-clinical changes is now possible. Thus, CMR may be ideal for cardiovascular assessment in pediatric CKD. This study aims to comprehensively assess cardiovascular function in pediatric CKD using CMR and determine its relationship with CKD severity.

METHODS

A total of 120 children (40 mild, 40 moderate, 20 severe pre-dialysis CKD subjects and 20 healthy controls) underwent CMR with non-invasive blood pressure (BP) measurements. Cardiovascular parameters measured included systemic vascular resistance (SVR), total arterial compliance (TAC), left ventricular (LV) structure, ejection fraction (EF), cardiac timings, radial and longitudinal systolic and diastolic myocardial velocities. Between group comparisons and regression modelling were used to identify abnormalities in CKD and determine the effects of renal severity on myocardial function.

RESULTS

The elevation in mean BP in CKD was accompanied by significantly increased afterload (SVR), without evidence of arterial stiffness (TAC) or increased fluid overload. Left ventricular volumes and global function were not abnormal in CKD. However, there was evidence of LV remodelling, prolongation of isovolumic relaxation time and reduced systolic and diastolic myocardial velocities.

CONCLUSION

Abnormal cardiovascular function is evident in pre-dialysis pediatric CKD. Novel CMR biomarkers may be useful for the detection of subtle abnormalities in this population. Further studies are needed to determine to prognostic value of these biomarkers.

Longitudinal assessment of myocardial function in childhood chronic kidney disease, during dialysis, and following kidney transplantation

BACKGROUND

Childhood chronic kidney disease (CKD) and dialysis are associated with increased long-term cardiovascular risk. We examined subclinical alterations in myocardial mechanics longitudinally in children with CKD, during dialysis, and following renal transplantation.

METHODS

Forty-eight children with CKD (stage III or higher) who received kidney transplants from 2008 to 2014 were included in a retrospective study and compared to 192 age- and sex-matched healthy children. Measurements of cardiac systolic and diastolic function were performed, and global longitudinal strain (GLS) and circumferential strain (GCS) were measured by speckle-tracking echocardiography at CKD, during dialysis, and 1 year following kidney transplantation. Mixed-effects modeling examined changes in GLS and GCS over different disease stages.

RESULTS

Children with CKD had a mean age of 10 ± 5 years and 67% were male. Eighteen children received preemptive transplantation. Children with CKD had increased left ventricular mass, lower GLS, and impaired diastolic function (lower E/A ratio and E' velocities) than healthy children. Changes in left ventricular diastolic parameters persisted during dialysis and after renal transplantation. Dialysis was associated with reduced GLS compared to CKD (β = 1.6, 95% confidence interval 0.2-3.0); however, this was not significant after adjustment for systolic blood pressure and CKD duration. Post-transplantation GLS levels were similar to those at CKD assessment. GCS was unchanged during dialysis but significantly improved following transplantation.

CONCLUSIONS

There are differences in diastolic parameters in childhood CKD that persist during dialysis and after transplantation. Systolic parameters are preserved, with significant improvement in systolic myocardial deformation following transplantation. The impact of persistent diastolic changes on long-term outcomes requires further investigation.

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.

Cardiovascular Phenotypes in Children with CKD: The 4C Study

BACKGROUND AND OBJECTIVES

Cardiovascular disease is the most important comorbidity affecting long-term survival in children with CKD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The Cardiovascular Comorbidity in Children with CKD Study is a multicenter, prospective, observational study in children ages 6-17 years old with initial GFR of 10-60 ml/min per 1.73 m2. The cardiovascular status is monitored annually, and subclinical cardiovascular disease is assessed by noninvasive measurements of surrogate markers, including the left ventricular mass index, carotid intima-media thickness, and central pulse wave velocity. We here report baseline data at study entry and an explorative analysis of variables associated with surrogate markers.

RESULTS

A total of 737 patients were screened from October of 2009 to August of 2011 in 55 centers in 12 European countries, and baseline data were analyzed in 688 patients. Sixty-four percent had congenital anomalies of the kidney and urinary tract; 26.1% of children had uncontrolled hypertension (24-hour ambulatory BP monitoring; n=545), and the prevalence increased from 24.4% in CKD stage 3 to 47.4% in CKD stage 5. The prevalence of left ventricular hypertrophy was higher with each CKD stage, from 10.6% in CKD stage 3a to 48% in CKD stage 5. Carotid intima-media thickness was elevated in 41.6%, with only 10.8% of patients displaying measurements below the 50th percentile. Pulse wave velocity was increased in 20.1%. The office systolic BP SD score was the single independent factor significantly associated with all surrogate markers of cardiovascular disease. The intermediate end point score (derived from the number of surrogate marker measurements >95th percentile) was independently associated with a diagnosis of congenital anomalies of the kidney and urinary tract, time since diagnosis of CKD, body mass index, office systolic BP, serum phosphorus, and the hemoglobin level.

CONCLUSIONS

The baseline data of this large pediatric cohort show that surrogate markers for cardiovascular disease are closely associated with systolic hypertension and stage of CKD.

Assessing longitudinal trends in cardiac function among pediatric patients with chronic kidney disease

BACKGROUND

Left ventricular diastolic dysfunction (LVDD) is an early marker of cardiac disease in pediatric chronic kidney disease (CKD), but few studies have analyzed longitudinal trends. We conducted a prospective 3-year follow-up study in pediatric CKD and kidney transplant (CKD-T) patients.

METHODS

The patient cohort comprised 30 CKD and 42 CKD-T patients. The results of annual clinical and echocardiographic analyses using tissue Doppler imaging (TDI) and pulse wave Doppler (PWD) were assessed, and associations to predictive risk factors were studied using multivariate modeling.

RESULTS

The mean age of CKD and CKD-T patients at inclusion was 9.8 ± 4.4 and 11.8 ± 4.3 years, respectively; the glomerular filtration rate was 35.3 ± 18.3 and 60.3 ± 18.8 mL/min/1.73 m(2), respectively. The prevalence of left ventricular diastolic dysfunction (LVDD), as assessed using TDI (lateral z-score e') was 7.1 and 12.5 % in CKD and CKD-T patients, respectively; the corresponding values with PWD E were 3.3 and 2.4 %, respectively. In unadjusted analyses, both TDI and PWD markers of diastolic function worsened over the follow-up period; following adjustments, an elevated systolic ambulatory blood pressure was the most important predictor of cardiac disease.

CONCLUSIONS

Children with CKD show early signs of LVDD, with TDI being more sensitive than PWD in terms of diagnostic potential. An increased ambulatory systolic blood pressure predicted progression in diastolic function, suggesting opportunities for future interventions.

KNOW-Ped CKD (KoreaN cohort study for outcomes in patients with pediatric CKD): Design and methods

Background

The global prevalence of chronic kidney disease (CKD) is increasing. In children, CKD exhibits unique etiologies and can have serious impacts on children’s growth and development. Therefore, an aggressive approach to preventing the progression of CKD and its complications is imperative. To improve the understanding and management of Asian pediatric patients with CKD, we designed and launched KNOW-Ped CKD (KoreaN cohort study for Outcome in patients With Pediatric Chronic Kidney Disease), a nationwide, prospective, and observational cohort study of pediatric CKD with funding from the Korean government.

Methods/design

From seven major centers, 450 patients <20 years of age with CKD stages I to V are recruited for the comprehensive assessment of clinical findings, structured follow-up, and bio-specimen collection. The primary endpoints include CKD progression, defined as a decline of estimated glomerular filtration rate by 50 %, and a requirement for renal replacement therapy or death. The secondary outcomes include the development of left ventricular hypertrophy or hypertension, impairment of growth, neuropsychological status, behavioral status, kidney growth, and quality of life.

Discussion

With this study, we expect to obtain more information on pediatric CKD, which can be translated to better management for the patients.

Trial registration

NCT02165878 (ClinicalTrials.gov), submitted on June 11, 2014.

Can ambulatory blood pressure monitoring detect early diastolic dysfunction in children with type 1 diabetes mellitus: correlations with B-type natriuretic peptide and tissue Doppler findings

AIM

To evaluate the relationship between 24-h blood pressure (BP) measurements and diastolic heart function evaluated by Doppler tissue imaging and B-type natriuretic peptide (BNP) levels in children with type 1 diabetes mellitus (DM).

PATIENTS AND METHODS

A total of 32 diabetic and 18 healthy children were enrolled. Spectral Doppler analysis and tissue Doppler measurements were performed by conventional echocardiography. The 24-h ambulatory BP and serum BNP levels were measured.

RESULTS

Analysis of ambulatory blood pressure monitoring (ABPM) recordings showed that median daytime diastolic BP load were significantly higher in diabetic patients compared to controls [12.35 (4.23-27.23) vs. 2.5 (0-8.7), p = 0.007]. Patients with elevated daytime systolic and diastolic BP loads had significantly higher BNP values compared to patients with normal BP load (31.4 ± 24.36 vs. 11.84 ± 11.25 pg/mL, p = 0.03 and 23.21 ± 15.12 vs. 12.12 ± 14.65 pg/mL, p = 0.03, respectively). Isovolemic contraction time (47.43 ± 7.84 vs. 42.27 ± 7.47, p = 0.045), isovolemic relaxation time (68.84 ± 10.43 vs. 58.77 ± 10.02, p = 0.02), and myocardial performance index (0.45 ± 0.10 vs. 0.37 ± 0.09, p = 0.02) as determined by tissue Doppler echocardiography were significantly high in diabetic patients compared to that of control cases. Ratio of mitral peak early diastolic flow velocity (E) to peak early diastolic myocardial velocities by tissue Doppler echocardiography (E') was also higher in patients with elevated daytime systolic BP load (E/E', 6.71 ± 1.97 vs. 4.91 ± 1.02, p = 0.04).

CONCLUSION

Elevated BP loads detected by 24-h ambulatory BP measurements in children with type 1 diabetes are associated with increased BNP levels and abnormal tissue Doppler echocardiography indices, indicating early stage cardiac dysfunction.