Impact of peritoneal transport characteristics on cardiac function in paediatric peritoneal dialysis patients: a Turkish Pediatric Peritoneal Dialysis Study Group (TUPEPD) report

The relationship between changes in peritoneal membrane solute transfer characteristics and cardiac remodeling in patients with peritoneal dialysis

INTRODUCTION

We aimed to determine the relationship between the dilatation of the heart chambers and the change in peritoneal membrane solute transfer characteristics (PMTC) in long-term peritoneal dialysis (PD) patients.

METHODS

This is a retrospective, single-center study including the follow-up of maintenance PD patients. According to the changes in PMTC from baseline to the last visit, patients were divided into three groups; stable (n = 11), increased (n = 41), and decreased transporters (n = 35).

RESULTS

Left atrium (LA) and Right ventricle (RV) dilatation were more prominent in the PMTC-decreased group compared to PMTC-increased and stable groups (p < 0.001 and p = 0.07, respectively). The Cox regression analysis showed that only decreased PMTC was associated with LA dilatation (HR 2.89 [CI 95%1.54, 5.45] p < 0.01) and RV dilatation (HR 3.01 [CI 95%1.40, 6.21] p < 0.01).

CONCLUSION

PD can be associated with unfavorable dynamic changes in cardiac structure and functions even at the subclinical level.

Non-genetic influences on lipoprotein(a) concentrations

An elevated level of lipoprotein(a) [Lp(a)] is a genetically regulated, independent, causal risk factor for cardiovascular disease. However, the extensive variability in Lp(a) levels between individuals and population groups cannot be fully explained by genetic factors, emphasizing a potential role for non-genetic factors. In this review, we provide an overview of current evidence on non-genetic factors influencing Lp(a) levels with a particular focus on diet, physical activity, hormones and certain pathological conditions. Findings from randomized controlled clinical trials show that diets lower in saturated fats modestly influence Lp(a) levels and often in the opposing direction to LDL cholesterol. Results from studies on physical activity/exercise have been inconsistent, ranging from no to minimal or moderate change in Lp(a) levels, potentially modulated by age and the type, intensity, and duration of exercise modality. Hormone replacement therapy (HRT) in postmenopausal women lowers Lp(a) levels with oral being more effective than transdermal estradiol; the type of HRT, dose of estrogen and addition of progestogen do not modify the Lp(a)-lowering effect of HRT. Kidney diseases result in marked elevations in Lp(a) levels, albeit dependent on disease stages, dialysis modalities and apolipoprotein(a) phenotypes. In contrast, Lp(a) levels are reduced in liver diseases in parallel with the disease progression, although population studies have yielded conflicting results on the associations between Lp(a) levels and nonalcoholic fatty liver disease. Overall, current evidence supports a role for diet, hormones and related conditions, and liver and kidney diseases in modifying Lp(a) levels.

Improved blood pressure and left ventricular remodelling in children on chronic intermittent haemodialysis: a longitudinal study

OBJECTIVES

We aimed to examine longitudinal changes in left ventricular (LV) structure and function and evaluate factors associated with LV remodelling in children on chronic haemodialysis.

METHODS

Retrospective longitudinal study including all children from the start of chronic haemodialysis with two or more m-mode 2D echocardiograms and tissue Doppler studies. Left ventricular mass (LVM) in g/m^2.7, geometry and LV function were compared at baseline (dialysis start) with follow-up studies at least 6 months following commencement. Left ventricular hypertrophy (LVH) was defined if greater than 95th percentile as per age-specific centiles. We also defined LVH as indexed LV mass index (LVMI) > 51 g/m^2.7 and using LV mass-for-height z-scores greater than the 95th percentile. Biochemical data, interdialytic weight change and blood pressure level were assessed for their association with change in indexed LVM.

RESULTS

Twenty-three of the 32 children < 18 years were included (n = 5, < 5 years) with last follow-up study performed following dialysis after a median (IQR) of 21 (10-34) months. The prevalence of LVH reduced significantly (69.6%, (n = 16/23) vs. 39.1% (n = 9/23), P = 0.002); LV geometry improved (13% concentric and 56.5% eccentric vs. 8.7% and 17.4% respectively) with mean ± SD reduction in indexed LVM (50.8 ± 23.1 g/m^2.7 vs. 38.6 ± 14.7 g/m^2.7, P = 0.002) and LV mass-for-height z-scores (0.67 ± 1.66 vs. - 0.46 ± 1.88, P = 0.002) from baseline to last follow-up respectively. There was no change in systolic function (LV fractional shortening, 37% vs. 38%, P = 0.39) and diastolic function (mean E/E' 10.8 vs. 9.0, P = 0.09). Multiple regression analysis identified improved systolic BP control (β = 0.41, P = 0.04) as an independent predictor for change in indexed LVM.

CONCLUSIONS

LV structure and function can improve in children despite long-term chronic intermittent haemodialysis. Cardiovascular health in this population does not always deteriorate but can be stabilised and indeed improved with optimal blood pressure management.

Free Water Transport and Its Association with Cardiovascular Status in Children on Peritoneal Dialysis

Background:Volume overload is one of the most important factors associated with left ventricular hypertrophy (LVH) and cardiovascular disease in chronic peritoneal dialysis (PD) patients. MiniPET is a reliable tool to evaluate free water transport (FWT). In a clinical setting, the significance of FWT has not been evaluated in terms of outcome in children on PD. The objective was to define a FWT value of clinical significance in children on PD, fixing its relationship to left ventricular mass index (LVMI) as a well-known outcome parameter.Methods:MiniPET was performed with 3.86% glucose, 1-h long, to measure FWT in PD patients > 6 years old. An echocardiogram (ECG) was performed within 2 months of the MiniPET. Left ventricular hypertrophy was defined as LVMI ≥ 38.6 g/height^2.7 (95th percentile). Receiver operating characteristic curve (ROC) analysis was used to determine the cut-off value of FWT searching the highest sensitivity and specificity to differentiate patients with normal/abnormal LVMI. A p < 0.05 was considered significant.Results:Forty-six studies were performed on 32 patients, 16 males; mean age 11.59 ± 3.07 years. Mean normalized FWT (nFWT) was 144.4 ± 84.8 mL/m², corresponding to 46.7% of total ultrafiltration. Mean LVMI was 42 ± 11.3 g/m^2.7 with a negative correlation to nFWT (p < 0.01). Eighteen out of 32 patients had LVH. The ROC analysis (nFWT vs LVMI) showed an area under the curve of 0.71 (95% confidence interval [CI], 0.53 - 0.89; p = 0.04), allowing a cut-off nFWT value of 110 mL/m² to be defined, dividing the population into 2 groups of patients according to the LVMI cut-off value of 38,6 g/m^2.7.Conclusions:The nFWT showed an inverse correlation to LVMI. A nFWT value < 110 mL/m² was significantly associated with LVH. The negative relationship observed between nFWT and LVMI, and the cut-off level for nFWT according to the 95th percentile of LVMI, suggest that the regular evaluation of nFWT could become a useful tool in assessing the capacity of PD treatment to keep patients' volume status under control, avoiding cardiovascular impairment.

Effect of the timing of dialysis initiation on left ventricular hypertrophy and ınflammation in pediatric patients

BACKGROUND

The optimal time for dialysis initiation in adults and children with chronic kidney disease remains unclear. The aim of this study was to evaluate the impact of dialysis timing on different outcome parameters, in particular left ventricular (LV) morphology and inflammation, in pediatric patients receiving peritoneal dialysis and hemodialysis.

METHODS

The medical records of pediatric dialysis patients who were followed-up in nine pediatric nephrology centers in Turkey between 2008 and 2013 were retrospectively reviewed. In addition to demographic data, we retrieved anthropometric measurements, data on dialysis treatment modalities, routine biochemical parameters, complete blood count, serum ferritin, parathormone, C-reactive protein (CRP), and albumin levels, as well as echocardiographic data and hospitalization records. The patients were divided into two groups based on their estimated glomerular filtration rate (eGFR) levels at dialysis initiation, namely, an early-start group, characterized by an eGFR of >10 ml/min/1.73 m², and a late-start group, with an eGFR of < 7 ml/min/1.73 m². The collected data were compared between these groups.

RESULTS

A total of 245 pediatric dialysis patients (mean age ± standard deviation 12.3 ± 5.1 years, range 0.5-21 years) were enrolled in this study. Echocardiographic data were available for 137 patients, and the mean LV mass index (LVMI) was 58 ± 31 (range 21-215) g/m^2.7. The LVMI was 75 ± 30 g/m^2.7(n = 81) and 34 ± 6 g/m^2.7(n = 56) in patients with or without LV hypertrophy (LVH) (p < 0.001). Early-start (eGFR >10 ml/min/1.73 m²) versus late-start dialysis (eGFR < 7 ml/min/1.73 m²) groups did not significantly differ in LVMI and LVH status (p > 0.05) nor in number of hospitalizations. Serum albumin levels were significantly higher in the early-dialysis group compared with the late-dialysis group (3.3 ± 0.7 vs. 3.1 ± 0.7 g/dl, respectively; p < 0.05). The early-start group had relatively higher time-averaged albumin levels (3.2 ± 0.5 vs. 3.1 ± 0.5 g/dl; p = > 0.05) and relatively lower CRP levels (3.64 ± 2.00 vs. 4.37 ± 3.28 mg/L, p > 0.05) than the late-start group, but these differences did not reach statistical significance.

CONCLUSION

Although early dialysis initiation did not have a significant effect on important clinical outcome parameters, including LVH, inflammatory state, and hospitalization, in our pediatric dialysis patients, this area of study deserves further attention.

Increased dialysate MCP-1 is associated with cardiovascular mortality in peritoneal dialysis patients: a prospective observational study

BACKGROUND

The aim of this study was to investigate the association between the dialysate MCP-1 (dMCP-1) and systemic inflammatory and nutritional markers in peritoneal dialysis (PD) patients. In addition, we examined the prognostic value of dMCP-1 on all-cause or cardiovascular mortality in these patients.

METHODS

We prospectively followed 169 prevalent PD patients from April 1st 2008 to December 31st 2012. At baseline, dMCP-1 and serum biochemical parameters including high sensitivity CRP (hs-CRP) and albumin were checked. All-cause mortality and cause of death were evaluated during the follow-up period. Based on the median level of dMCP-1, patients were classified as either low or high dMCP-1 groups.

RESULTS

Mean age, hs-CRP, and D/Pcr ratio at 4 h were significantly higher, while serum albumin levels and %lean body mass (LBM) were significantly lower in the high dMCP-1 group. During the mean follow-up period of 47.7 months, all-cause mortality and cardiovascular mortality rate were significantly higher in the high dMCP-1 group (9.6 and 6.3 per 100 person-years, respectively) compared to the low dMCP-1 group (5.1 and 3.1 per 100 person-years, respectively; p = 0.021, 0.038). In multivariate Cox analysis, high dMCP-1 was a significant independent predictor of all-cause mortality (hazard ratio: 1.83, 95% confidence interval: 1.03-3.24, p = 0.039).

CONCLUSIONS

dMCP-1 levels are closely correlated with nutritional and systemic inflammatory markers in PD patients. In addition, increased dMCP-1 is significantly associated with higher all-cause and cardiovascular mortality. These findings suggest that local peritoneal inflammation could contribute to poor clinical outcomes in PD patients.

Cardiovascular changes during chronic hypertensive states

It is well established that elevated blood pressure constitutes a major risk factor for coronary heart disease, arrythmias, heart failure, cerebrovascular disease, peripheral artery disease and renal failure. Blood pressure level and the duration of arterial hypertension (HTN) impact target organ damage. Many studies in adults have demonstrated the role of antihypertensive therapy in preventing cardiovascular (CV) events. The so-called hard end-points, such as death, myocardial infarction (MI) or stroke, are rarely seen in children, but intermediate target organ damage, including left ventricular hypertrophy, increased intima-media thickness and microalbuminuria, is already detectable during childhood. The goal of antihypertensive treatment is to reduce the global risk of CV events. In the adult population stratification of CV risk is based on blood pressure level, risk factors, subclinical target organ damage and established CV and kidney disease. Increased CV risk begins early in the course of kidney disease, and CV diseases are the most frequent cause of morbidity and mortality in patients with chronic kidney disease (CKD). Children with CKD are especially prone to the long-term effects of CV risk factors, which result in high morbidity and mortality in young adults. To improve the outcome, pediatric and adult CKD patients require nephro- and cardioprotection.

Peritoneal dialysis in children with end-stage renal disease

Peritoneal dialysis is the preferred chronic dialysis modality for most children owing to its almost universal applicability and superior compatibility with lifestyle over other modalities. Although technological advances and increasing clinical experience have impacted favorably on patient and technique survival, clinical research in pediatric peritoneal dialysis has been hampered by the low incidence of end-stage renal disease (ESRD) in the pediatric population. To overcome this limitation, several international registries have emerged in the past few years to complement other long-standing registries, which together have provided useful information regarding technique-specific complications and comorbidities associated with ESRD in children undergoing chronic peritoneal dialysis. In this Review, we summarize the most relevant findings from these studies, highlighting the substantial variation in patient conditions, peritoneal dialysis practices and management of comorbidities encountered in different parts of the world.

Cardiac geometry in children receiving chronic peritoneal dialysis: findings from the International Pediatric Peritoneal Dialysis Network (IPPN) registry

BACKGROUND AND OBJECTIVES

Left ventricular hypertrophy (LVH) is an independent risk factor and an intermediate end point of dialysis-associated cardiovascular comorbidity. We utilized a global pediatric registry to assess the prevalence, incidence, and predictors of LVH as well as its evolution in the longitudinal follow-up in dialyzed children.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Cross-sectional echocardiographic, clinical, and biochemical data were evaluated in 507 children on peritoneal dialysis (PD), and longitudinal data were evaluated in 128 patients. The 95(th) percentile of LV mass index relative to height age was used to define LVH.

RESULTS

The overall LVH prevalence was 48.1%. In the prospective analysis, the incidence of LVH developing de novo in patients with normal baseline LV mass was 29%, and the incidence of regression from LVH to normal LV mass 40% per year on PD. Transformation to and regression from concentric LV geometry occurred in 36% and 28% of the patients, respectively. Hypertension, high body mass index, use of continuous ambulatory peritoneal dialysis, renal disease other than hypo/dysplasia, and hyperparathyroidism were identified as independent predictors of LVH. The use of renin-angiotensin system (RAS) antagonists and high total fluid output (sum of urine and ultrafiltration) were protective from concentric geometry. The risk of LVH at 1 year was increased by higher systolic BP standard deviation score and reduced in children with renal hypo/dysplasia.

CONCLUSIONS

Using height-adjusted left ventricular mass index reference data, LVH is highly prevalent but less common than previously diagnosed in children on PD. Renal hypo/dysplasia is protective from LVH, likely because of lower BP and polyuria. Hypertension, fluid overload, and hyperparathyroidism are modifiable determinants of LVH.

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.

Peritoneal dialysis tailored to pediatric needs

Consideration of specific pediatric aspects is essential to achieve adequate peritoneal dialysis (PD) treatment in children. These are first of all the rapid growth, in particular during infancy and puberty, which must be accompanied by a positive calcium balance, and the age dependent changes in body composition. The high total body water content and the high ultrafiltration rates required in anuric infants for adequate nutrition predispose to overshooting convective sodium losses and severe hypotension. Tissue fragility and rapid increases in intraabdominal fat mass predispose to hernia and dialysate leaks. Peritoneal equilibration tests should repeatedly been performed to optimize individual dwell time. Intraperitoneal pressure measurements give an objective measure of intraperitoneal filling, which allow for an optimized dwell volume, that is, increased dialysis efficiency without increasing the risk of hernias, leaks, and retrofiltration. We present the concept of adapted PD, that is, the combination of short dwells with low fill volume to promote ultrafiltration and long dwells with a high fill volume to improve purification within one PD session. The use of PD solutions with low glucose degradation product content is recommended in children, but unfortunately still not feasible in many countries.

Left atrial volume is an independent predictor of mortality in CAPD patients

BACKGROUND

Echocardiography is an established technique to estimate the risk for cardiovascular complications in patients with end-stage renal disease (ESRD). An enlarged left atrium (LA) has recently emerged as a marker of adverse cardiovascular outcomes in various pathologic conditions. However, there have been few studies to evaluate its prognostic value in patients with ESRD, particularly those receiving continuous ambulatory peritoneal dialysis (CAPD).

METHODS

We conducted an observational cohort study to investigate whether enlarged LA can predict patient outcome in 216 patients with CAPD. Study outcomes were all-cause and cardiovascular mortality.

RESULTS

Increased left atrium volume index (LAVI > 32 mL/m(2)) was observed in 99 (45.8%) of the CAPD patients. During the follow-up (26.3 ± 18.6 months), 20 patients (9.3%) died. Kaplan-Meier analysis revealed that the 5-year survival rate was significantly lower in patients with LAVI > 32 mL/m(2) than those with LAVI ≤ 32 mL/m(2) (69 versus 82%, P = 0.024). In multivariate analyses adjusted for echocardiographic parameters and clinical and laboratory data, increased LAVI was an independent predictor of all-cause mortality [hazard ratio (HR) 1.05, 95% confidence interval (CI) 1.01-1.10, P = 0.03] and cardiovascular mortality (HR 1.08, 95% CI 1.02-1.14, P = 0.006). Furthermore, increased LAVI provided the highest predictive value for all-cause mortality [area under the receiver operating characteristic curve (AUC) = 0.766, P < 0.001] and cardiovascular mortality (AUC = 0.836, P < 0.001) among the measured echocardiographic parameters.

CONCLUSIONS

We showed that increased LAVI predicted adverse outcomes better than other echocardiographic parameters in patients with CAPD.