Changes of blood pressure and left ventricular mass in pediatric renal transplantation

The significance of central blood pressure for cardiovascular target organ damage in children and adolescents after kidney transplantation

BACKGROUND

Cardiovascular (CV) complications are important causes of morbidity and mortality in children after kidney transplantation (KTx). In adults, central blood pressure (cBP) is an accepted predictor of CV sequelae. We aimed to assess the prognostic value of cBP over peripheral blood pressure (pBP) for existing CV damage.

METHODS

We measured cBP and pBP in 48 pediatric KTx recipients (mean age: 13.5 ± 4.2 years). Assessment of left ventricular mass index (LVMI) and aortic pulse wave velocity (PWV) allowed detection of CV target organ damage. LVMI and PWV were used as endpoints in multivariable linear regression models, in which cBP and pBP were compared for their predictive value.

RESULTS

Using cBP z-scores, we identified a larger number of patients with uncontrolled or untreated hypertension compared to pBP (36% vs. 7%). Central systolic blood pressure (cSBP) was a significant independent predictor of LVMI, while peripheral systolic blood pressure (pSBP) was not. Comparing central (cDBP) and peripheral (pDBP) diastolic blood pressure for their predictive value on PWV revealed a greater estimate for cDBP (0.035 vs. 0.026 for pDBP) along with a slightly better model fit for cDBP.

CONCLUSIONS

Our data in a small group of patients provide first evidence that cBP measurements in pediatric KTx recipients might be helpful in identifying patients at risk for the development of CV sequelae. Investigating a larger patient number, ideally repeatedly, is needed to create further evidence supporting our findings. In light of available devices measuring cBP noninvasively, the implementation of such clinical studies post-KTx care should be feasible. A higher resolution version of the Graphical abstract is available as Supplementary information.

Prevalence of masked hypertension and its association with left ventricular hypertrophy in children and young adults with chronic kidney disease: a systematic review and meta-analysis

OBJECTIVES

There are limited studies using ambulatory blood pressure monitoring (ABPM) to assess blood pressure (BP) status in young patients with chronic kidney disease (CKD) on dialysis or after kidney transplantation. The aim of this meta-analysis is to estimate the prevalence of both white-coat hypertension (WCH) and masked hypertension, along with the prevalence of left ventricular hypertrophy (LVH), in children and young adults with CKD on dialysis or after kidney transplantation.

METHODS

We performed a systematic review and meta-analysis of observational studies assessing the prevalence of BP phenotypes using ABPM, in children and young adults with CKD stages 2-5d. Records were identified by search in databases (Medline, Web of Science, CENTRAL) and sources of grey literature, until 31 December 2021. A random-effects meta-analysis of proportions (double arcsine transformation) was conducted.

RESULTS

Ten studies were included in the systematic review, reporting data from 1140 individuals (children and young adults with CKD with a mean age of 13.79 ± 4.35 years). Masked hypertension and WCH were diagnosed in 301 and 76 patients, respectively. It was estimated an overall pooled masked hypertension prevalence of 27% [95% confidence interval (95% CI) 18-36, I2  = 87%] and an overall pooled WCH prevalence of 6% (95% CI 3-9, I2  = 78%). Among kidney transplant recipients, masked hypertension had a prevalence of 29% (95% CI 14-47, I2  = 86%). The prevalence of LVH was found 28% (95% CI 0.19-0.39) in a total of 238 CKD patients with ambulatory hypertension. In 172 CKD patients with masked hypertension, LVH was present in 49, with the estimated prevalence being 23% (95% CI 0.15-0.32).

CONCLUSION

Masked hypertension has a significant prevalence in children and young adults with CKD. Masked hypertension carries an adverse prognosis, with an increased risk of LVH, warranting clinical attention when assessing cardiovascular risk in this population. Therefore, ABPM and echocardiography is of high importance when assessing BP status in children with CKD.

PROTOCOL REGISTRATION NUMBER DOI

10.17605/OSF.IO/UKXAF.

Hypertension in Pediatric Solid Organ Transplant Recipients

PURPOSE OF REVIEW

To review the current literature regarding hypertension (HTN) following pediatric solid organ transplant (SOTx), including definition, prevalence, risk factors, outcomes, and treatment.

RECENT FINDINGS

In recent years several new guidelines for the definition, monitoring, and management of pediatric HTN have been published, but with no specific recommendations regarding SOTx recipients. HTN remains highly prevalent, yet underdiagnosed and undertreated in kidney transplant (KTx) recipients, especially when ambulatory blood pressure monitoring (ABPM) is utilized. There are little data regarding its prevalence in other SOTx recipients. HTN in this population is multifactorial and is associated with HTN status prior to Tx, demographic factors (age, sex, and race), weight status, and immunosuppression protocol. HTN is associated with subclinical cardiovascular (CV) end-organ damage, including left ventricular hypertrophy (LVH) and arterial stiffness, yet there are no recent data regarding its long-term outcomes. There are also no updated recommendations regarding the optimal management of HTN in this population. Given its high prevalence and the young age of this population facing years at increased CV risk, post-Tx HTN requires more clinical attention (routine monitoring, frequent application of ABPM, better BP control). Additional research is needed for a better understanding of its long-term outcomes as well as its treatment and treatment goals. Much more research is needed regarding HTN in other pediatric SOTx populations.

Longitudinal Changes in Cardiac Structure and Function in Pediatric Kidney Transplant Recipients

BACKGROUND

Cardiovascular disease results in increased morbidity and mortality in pediatric kidney transplant recipients. Longitudinal changes in cardiac structure and function and the association with blood pressure control over time in pediatric kidney transplant recipients are unknown.

METHODS

To determine the influence of blood pressure control on cardiac changes following pediatric kidney transplant, we conducted a retrospective cohort study of children who received their first kidney transplant at the Hospital for Sick Children from 2004 to 2015. Children were followed until transfer to adult care or censoring in July 2018. Cardiac structure and function parameters were collected from clinical echocardiograms and assessed using standardized scores. Blood pressure control was determined by systolic blood pressure Z scores (above or below the 90th percentile) in combination with antihypertensive medications. A segmented mixed-effects model assessed Z scores of interventricular septum thickness, left ventricular end-diastolic dimension, and left ventricular posterior wall dimension.

RESULTS

Of 142 children included, 58% were men, mean age at transplant was 11 (±4.5) years, and average follow-up time was 4 (±3) years. All cardiac structural Z scores improved during follow-up. Interventricular septum thickness normalized at 4.0 years post-transplant. Left ventricular end-diastolic dimension normalized at 1.5 years post-transplant. Left ventricular posterior wall dimension normalized at 6.3 years post-transplant. Left ventricular mass index showed sustained improvement up to 12 years post-transplant. Individuals with uncontrolled blood pressure had increased left ventricular mass (β=2.97 [95% CI, 0.77-5.16]).

CONCLUSIONS

Cardiac structural abnormalities improve following kidney transplantation and normalize within 7 years, especially with controlled blood pressure. Strict blood pressure control is critical after pediatric kidney transplantation.

Nocturnal hypertension and left ventricular hypertrophy in pediatric renal transplant recipients in South India

HTN after renal transplantation is associated with cardiovascular morbidity. ABPM allows diagnosis of masked HTN and isolated nocturnal HTN. Longitudinal ABPM data in children post-transplant are limited. ABPM was performed in children post-transplant and repeated in 6-12 months. BP indices were used to determine the prevalence of masked HTN, masked uncontrolled HTN (masked HTN in patients on antihypertensive medications), and isolated nocturnal HTN. Linear regression determined the association between LVMI and ABPM indices. Thirty children underwent a baseline ABPM. Ambulatory HTN was present in 25 (83%). Masked HTN was present in 18 (60%) and isolated nocturnal HTN in 13 (43%). Nocturnal ambulatory BP was higher than corresponding daytime BPs (P < .001 for systolic and diastolic) and 25 (83%) had a blunted nocturnal dip. Prednisone dose predicted nocturnal DBP index and DBP load (r²  = .40, P = .024 and r²  = .178, P = .02). ABPM was repeated in 18 patients within 11 (±3) months. BP indices decreased with time, but nocturnal BPs remained higher than daytime (P < .001 for SBP and DBP). Blunted nocturnal dip did not improve. LVH was present in 12 (57%). LVMI was directly related to the nocturnal SBP index (r²  = .377, P = .003) and nocturnal DBP index (r²  = .493, P < .001). We found no association between LVMI and daytime BP indices. The prevalence of masked HTN, isolated nocturnal HTN, and blunted nocturnal dip was high in children with kidney transplants. Nocturnal BP predicted LVMI. Ambulatory BP improved on longitudinal follow-up, but the pattern of isolated nocturnal HTN persisted.

Subclinical Organ Damage in Children and Adolescents with Hypertension: Current Guidelines and Beyond

High blood pressure (BP) is becoming a growing health issue even in children and adolescents. Moreover, BP elevation in youth frequently translates into children and adult hypertension contributing to the development of cardiovascular disease. The detection of early markers of vascular damage, potentially leading to overt cardiovascular disease, is important for clinical decisions about if and how to treat hypertension and can be useful in monitoring the effectiveness of the treatment. The purpose of this review is to summarize the actual knowledge about subclinical organ damage (SOD) in hypertensive children and adolescents and its association with cardiovascular disease in children and young adults. Our focus is especially put on left ventricular mass, pulse wave velocity, carotid intima-media thickness and microalbuminuria. We also want to address the scientific evidence about possible regression of SOD and cardiovascular risk with the use of behavioural and specific anti-hypertensive therapy. Indications from current guidelines are critically discussed.

Inadequate blood pressure control demonstrated by ambulatory blood pressure monitoring in pediatric renal transplant recipients

BACKGROUND

Adequate BP control in RT recipients should not rely only by normal office BP but also on normal 24-hour BP. This study aims to assess adequacy of BP control by ABPM and to assess ABPM parameters associated with LVMI in pediatric RT recipients.

MATERIALS AND METHODS

Patients aged 5-20 years who have been followed after RT were enrolled. Demographic data and BP assessed by office and ABPM were collected. Echocardiography was performed to detect LVMI.

RESULTS

Thirty RT recipients (18 males) with median age of 15 years (IQR 13-18.5) were included. Among 23 patients who were taking antihypertensive drugs, uncontrolled hypertension was detected in 34.8% and 78.3% by office BP measurement and ABPM, respectively. Thus, the difference in prevalence of uncontrolled hypertension observed by ABPM versus office BP was 43.5%. Those seven patients who were not taking antihypertensive drugs because of normal office BP, four patients (57.1%) had masked hypertension and one patient had elevated BP. Fifteen patients have progression of LVH after RT. Multivariate analysis revealed that age (OR 1.369, 95%CI 0.985-1.904, P-value = 0.062) had a trend to be associated with progression of LVH. Moreover, nighttime systolic BP z-score was significantly correlated with LVMI (r = 0.551, P-value = 0.002).

CONCLUSION

The difference in prevalence of uncontrolled hypertension uncovered by ABPM was 43.5%. Nighttime SBP z-score was significantly correlated with LVMI.

Home Blood Pressure Monitoring in Children and Adolescents: Systematic Review of Evidence on Clinical Utility

PURPOSE OF REVIEW

For the accurate diagnosis and management of hypertension, out-of-office blood pressure evaluation using ambulatory (ABPM) or home monitoring (HBPM) is currently recommended. In children, there is considerable evidence on the clinical utility of ABPM, whereas the evidence on HBPM is limited. This systematic review presents (i) the benefits of HBPM in children; (ii) the evidence on normal range, diagnostic accuracy, and relationship with preclinical organ damage; and (iii) guidance for devices, monitoring schedule, and interpretation.

RECENT FINDINGS

HBPM is a useful adjunct to the conventional office measurements for the evaluation of children with suspected or treated hypertension. HBPM is feasible in children and has good reproducibility, diagnostic accuracy and acceptability by users, and relatively low cost. Thus, it has greater potential for widespread and long-term use than ABPM, which is more expensive and often not available or not tolerated. Automated monitors that have been clinically validated specifically in children should be used with appropriate cuff size. HBPM for 7 days (minimum 3) with duplicate morning and evening measurements (minimum 12 readings) should be performed in children with suspected or treated hypertension before each office visit. Until more data become available, in case of diagnostic disagreement between office blood pressure and HBPM, treatment decisions should be based on ABPM. HBPM is clinically useful in children with hypertension. More research is needed on its clinical application, and more automated devices need to be clinically validated in this population.

Ambulatory Blood Pressure, Left Ventricular Hypertrophy, and Allograft Function in Children and Young Adults After Kidney Transplantation

BACKGROUND

Hypertension is a common complication and is an important risk factor for graft loss and adverse cardiovascular outcomes in pediatric kidney transplantation. Ambulatory blood pressure monitoring (ABPM) is the preferred method to characterize blood pressure status.

METHODS

We conducted a retrospective review of a large cohort of children and young adults with kidney transplant to estimate the prevalence of abnormal ambulatory blood pressure (ABP), assess factors associated with abnormal ABP, and examine whether ambulatory hypertension is associated with worse allograft function and left ventricular hypertrophy (LVH).

RESULTS

Two hundred twenty-one patients had ABPM, and 142 patients had echocardiographic results available for analysis. One third of the patients had masked hypertension, 32% had LVH, and 38% had estimated glomerular filtration rate less than 60 mL/min per 1.73 m. African-American race/Hispanic ethnicity and requirement for more than 1 antihypertensive medication were independently associated with having masked hypertension. In a multivariate analysis, abnormal blood pressure (masked or sustained hypertension combined) was an independent predictor for LVH among patients not receiving antihypertensive treatment (P = 0.025). In a separate analysis, the use of antihypertensive medications was independently associated with worse allograft function (P = 0.002) although abnormal blood pressure was not a significant predictor.

CONCLUSIONS

In young kidney transplant recipients, elevated ABP is frequently unrecognized and undertreated. The high prevalence of abnormal ABP, including masked hypertension, and its association with LVH supports the case for routine ABPM and cardiac structure evaluation as the standard of care in these patients.

Long-Term Changes in Blood Pressure After Pediatric Kidney Transplantation

BACKGROUND

Hypertension presents high prevalence rates following kidney transplantation (Tx). The aims of the present study were to investigate the prevalence and possible risk factors for hypertension and blood pressure (BP) control over time after pediatric kidney Tx, as well as to assess possible effects of hypertension on graft survival.

METHODS

We reviewed the medical records of all pediatric kidney recipients followed up in our pediatric nephrology department. Hypertension was defined as systolic and/or diastolic BP greater than the 95th percentile for age and sex, or as being on antihypertensive medication. BP control was defined as normotension while on antihypertensive medication.

RESULTS

The study population included 74 pediatric kidney recipients (median age 11 years). The prevalence of hypertension was found 77% before Tx, 82.4%, 71.7%, and 61% at 1, 5, and 10 years after Tx, respectively. Deceased donor Tx and pre-transplant hypertension on antihypertensive medication were significant risk factors for hypertension after kidney Tx over the follow-up period. BP control among patients on antihypertensive treatment was 16.7% before Tx, 43.8%, 66.7%, and 42.9% at 1, 5, and 10 years post-Tx, respectively. Hypertensive patients at 10 years post-Tx had 8.079 times higher hazard of graft loss compared to normotensives (95% CI 1.561-41.807, P < 0.05).

CONCLUSIONS

Hypertension remains a frequent complication in pediatric kidney recipients even years after kidney Tx. BP control by antihypertensive treatment is unsatisfactory in about half of the patients. The adverse effects of hypertension on graft survival may appear in the long-term.

Assessment and management of hypertension in transplant patients

Hypertension in renal transplant recipients is common and ranges from 50% to 80% in adult recipients and from 47% to 82% in pediatric recipients. Cardiovascular morbidity and mortality and shortened allograft survival are important consequences of inadequate control of hypertension. In this review, we examine the epidemiology, pathophysiology, and management considerations of post-transplant hypertension. Donor and recipient factors, acute and chronic allograft injury, and immunosuppressive medications may each explain some of the pathophysiology of post-transplant hypertension. As observed in other patient cohorts, renal artery stenosis and adrenal causes of hypertension may be important contributing factors. Notably, BP treatment goals for renal transplant recipients remain an enigma because there are no adequate randomized controlled trials to support a benefit from targeting lower BP levels on graft and patient survival. The potential for drug-drug interactions and altered pharmacokinetics and pharmacodynamics of the different antihypertensive medications need to be carefully considered. To date, no specific antihypertensive medications have been shown to be more effective than others at improving either patient or graft survival. Identifying the underlying pathophysiology and subsequent individualization of treatment goals are important for improving long-term patient and graft outcomes in these patients.

A longitudinal retrospective analysis of left ventricular mass in a cohort of pediatric kidney transplant recipients

Childhood end-stage kidney disease is associated with increased risk for early adulthood cardiovascular (CV) morbidity and mortality. Increased LVM is an early indicator of CV disease. Previous studies have suggested that LVM decreases after kidney transplantation; however, trends have been inconsistent. A single center retrospective longitudinal cohort analysis of LVM, documented annually, starting before kidney transplantation for up to 10 yr after transplantation was performed. BP documented by annual 24-h ambulatory monitoring studies, and BMI values were also reviewed. Twenty-seven children followed for a mean period of 5.3 yr were included. Depending on definition of LVH, its prevalence pretransplant and in the first years post-transplant was up to 33% dropping to 0-25% thereafter. Individual longitudinal LVM z-score trends were highly variable but generally trended toward the mean immediately after transplant and toward negative values in the following years. BP was stable during the follow-up period while mean annual BMI increased in the first-year post-transplant but declined thereafter. In a cohort of pediatric renal transplant recipients, prevalence of LVH decreased after transplant; however, individual longitudinal LVM trends were highly variable among patients. Prospective studies are needed to correlate individual LVM trends with outcomes.

Cardiovascular risk factors in children after kidney transplantation--from short-term to long-term follow-up

Cardiovascular-related mortality is 100-fold higher in pediatric renal transplant recipients than in the age-matched general population. Seventy-seven post-renal transplant children's charts were reviewed for cardiovascular risk factors at two and six months after transplantation (short term) and at two yr after transplantation and the last follow-up visit (mean 7.14 ± 3.5 yr) (long term). Significant reduction was seen in cardiovascular risk factors prevalence from two months after transplantation to last follow-up respectively: Hypertension from 52.1% to 14%, hypercholesterolemia from 48.7% to 33%, hypertriglyceridemia from 50% to 12.5%, anemia from 29.6% to 18.3%, hyperparathyroidism from 32% to 18.3% and hyperglycemia from 11.7% to 10%, and left ventricular hypertrophy from 25.8% at short term to 15%. There was an increase in the prevalence of obesity from 1.5% to 3.9% and of CKD 3-5 from 4.75% to 24%. The need for antihypertensive treatment decreased from 54% to 42%, and the percentage of patients controlled by one medication rose from 26% to 34%, whereas the percentage controlled by 2, 3, and 4 medications decreased from 21.9%, 5.5%, and 1.4% to 6%, 2%, and 0. Children after renal transplantation appear to have high rates of cardiovascular risk factors, mainly on short-term follow-up.

Ambulatory blood pressure monitoring in pediatric renal transplantation

Hypertension is a common and serious complication after renal transplantation. It is an important risk factor for graft loss and adverse cardiovascular outcomes. Blood pressure (BP) in transplanted children should be measured not only by clinic BP (cBP) measurement, but also by ambulatory blood pressure monitoring (ABPM), because ABPM has distinct advantages over cBP, specifically the ability to reveal nocturnal, masked or white-coat hypertension. These types of hypertension are common in transplanted children (nocturnal hypertension 36-71 %, masked hypertension 24-45 %). It may also reveal uncontrolled hypertension in treated children, thereby improving control of hypertension. Regular use of ABPM and ABPM-guided therapy of hypertension may help to decrease cardiovascular and renal target organ damage in transplanted children. Therefore, ABPM should be routinely performed in all transplanted children at least once a year, regardless of the values of cBP.

Possible correlation among echocardiographic measures, serum brain natriuretic peptide, and angiotensin II levels in hypertensive kidney transplanted children

OBJECTIVES

Ambulatory blood pressure monitoring is the standard for determining patients at risk of hypertension. Left ventricular hypertrophy is common in kidney transplant recipients. We evaluated the correlation between blood pressure measures achieved by ambulatory blood pressure monitoring and conventional (office) methods.

MATERIALS AND METHODS

This cross-sectional study was done from December 2009 to October 2010 at Alzahra Hospital in Isfahan, Iran. Sixty five participants, 35 kidney transplant recipients under 20 years old, and 30 control subjects of the same age were recruited. Five kidney recipients did not complete the study and were excluded. Blood pressure was measured by ambulatory blood pressure monitoring and conventional methods. Echocardiographic study was done for kidney transplant recipients. Serum brain natriuretic peptide and angiotensin II levels were determined in case and control groups.

RESULTS

Office-recorded systolic and/or diastolic hypertension was observed in 43.4% and 55.3% of patients. According to ambulatory blood pressure monitoring, 86% of kidney transplant recipients had systolic BP load. Left ventricular hypertrophy (defined according to the left ventricular mass index [left ventricular mass index/height]) was seen in 53.3% of the patients. The existence of left ventricular hypertrophy revealed a positive correlation with ambulatory blood pressure monitoring systolic and diastolic night blood pressure and systolic nondipper. Left ventricular mass index showed a positive correlation with brain natriuretic peptide level. Furthermore, the existence of left ventricular hypertrophy was positively correlated with angiotensin II level.

CONCLUSIONS

Only ambulatory blood pressure monitoring systolic and diastolic blood pressures (nondippers) were positively correlated with left ventricular hypertrophy and higher left ventricular mass index. Serum levels of brain natriuretic peptide and angiotensin II had a positive relation with left ventricular hypertrophy. Measuring brain natriuretic peptide and angiotensin II in the clinical setting screens patients at risk of left ventricular hypertrophy.

Cardiac magnetic resonance imaging in children with chronic kidney disease and renal transplantation

CV disease is the major cause of death in patients with CKD. Recently, CMR imaging emerges as a complementary method providing advantages in cardiac assessment; however, data on CMR in pediatric CKD are scarce. We performed CMR in 15 children: two with CKD, six on peritoneal dialysis, seven on hemodialysis, and in 18 children 5.1 (0.4-15.4) yr after kidney Tx. Eight children underwent CMR six months before and after Tx. Results are presented as mean z score ± SD. LV EF was higher and in the normal range in Tx patients compared with CKD (-0.3 ± 1 vs. -2.1 ± 1.6, respectively, p < 0.05), whereas RV EF was similar (-0.9 ± 1.4 vs. -0.9 ± 1.8, p = n.s.). End-diastolic and end-systolic LV volume index (0 ± 1.7 vs. 2.1 ± 3.1; 0.2 ± 1.2 vs. 3.1 ± 3.7, both p < 0.05) and LV mass index (1.4 ± 1.5 vs. 3.4 ± 2.9, p < 0.05) were lower in Tx children. All parameters improved in the eight children after Tx. In conclusion, our CMR analysis suggests marked improvement of cardiac function and morphology in children after kidney Tx. CMR might be an appropriate complementary method for measuring detailed cardiac status in children with CKD.

Cardiovascular disease in children with chronic kidney disease

More than a decade ago, cardiovascular disease (CVD) was recognized as a major cause of death in children with advanced CKD. This observation has sparked the publication of multiple studies assessing cardiovascular risk, mechanisms of disease, and early markers of CVD in this population. Similar to adults, children with CKD have an extremely high prevalence of traditional and uremia-related CVD risk factors. Early markers of cardiomyopathy, such as left ventricular hypertrophy and dysfunction, and early markers of atherosclerosis, such as increased carotid artery intima-media thickness, carotid arterial wall stiffness, and coronary artery calcification, are frequently present in these children, especially those on maintenance dialysis. As a population without preexisting symptomatic cardiac disease, children with CKD potentially receive significant benefit from aggressive attempts to prevent and treat CVD. Early CKD, before needing dialysis, is the optimal time to both identify modifiable risk factors and intervene in an effort to avert future CVD. Slowing the progression of CKD, avoiding long-term dialysis and, if possible, conducting preemptive transplantation may represent the best strategies to decrease the risk of premature cardiac disease and death in children with CKD.

The influence of low donor age, living related donation and pre-emptive transplantation on end-organ damage based on arterial hypertension after paediatric kidney transplantation

BACKGROUND

To date, no study has described the pre-transplant and transplant risk factors for end-organ damage based on arterial hypertension in children after kidney transplantation (KTX).

METHODS

A retrospective chart review was performed of 206 children with KTX between 1991 and 2007. Patients<120 cm were excluded as no validated percentiles for 24-h ambulant blood pressure monitoring (ABPM) exist. Complete data sets were available for 116 patients. Data were recorded at 12, 24 and 36 months post- KTX. We analysed the influence of donor age, age at transplantation, pre-emptive transplantation, living or deceased transplantation and glomerular filtration rate (GFR) on the presence of end-organ damage, ABPM, ABPM standard deviation score and the numbers of anti-hypertensives used.

RESULTS

Lower donor age and the decade of transplantation were associated with less detection of end-organ damage (P=0.001). A lower need for anti-hypertensive medication (P=0.001) was detected in children who received organs from living donors and from deceased donors with a donor age<35 years and who were transplanted pre-emptively. Low recipient age was the only factor associated with lower ABPM (P=0.001). In our study, the type of immunosuppressive regimen and the GFR had no influence on the blood pressure.

CONCLUSIONS

It may be speculated that the risk of arterial hypertension and associated end-organ damage in children after KTX could be reduced by using organs from young donors with an advantage for living related and pre-emptive donation.

Long-term cardiovascular effects of pre-transplant native kidney nephrectomy in children

Left ventricular (LV) hypertrophy (H) and hypertension are prevalent in children with end-stage renal disease (ESRD) and after renal transplantation. Severe hypertension prior to renal transplantation has traditionally been an indication for native kidney nephrectomy. The impact of nephrectomy on cardiovascular disease has not been well documented. We retrospectively evaluated echocardiographic and ambulatory blood pressure monitoring (ABPM) data in 67 young adults who had undergone transplantation in the pediatric age with a mean follow-up of 10.4 years. Unilateral or bilateral nephrectomies had been performed in 32 patients. The number of antihypertensive drugs used prior to transplantation was significantly higher in the nephrectomized groups. At follow-up the amount of antihypertensive medications was similar between groups and no significant differences were observed in mean arterial blood pressure (MAP) or LV mass index (LVMi). LVH was observed in 50% of non-nephrectomized patients, 45.4% of patients with unilateral nephrectomy, and 44.4% of patients without native kidneys (p = n.s.). In conclusion, unilateral or bilateral nephrectomies prior to transplantation do not appear to influence blood pressure control or the prevalence of LVH after renal transplantation. Longitudinal studies with repeated assessment of LVMi, before and after renal transplantation, are needed to assess the impact of residual activity of native kidneys on arterial blood pressure and cardiac structural changes, even in normotensive patients, to evaluate cardiovascular morbidity.

Early origins of cardiovascular disease in pediatric chronic kidney disease

The importance of cardiovascular disease in adults with chronic kidney disease is now well recognized. For children who develop chronic kidney disease, cardiovascular disease is also a leading cause of eventual morbidity and mortality. Although the clinical manifestations of cardiovascular disease may not be apparent until later, early subclinical findings can be observed even during childhood. This review updates the reader on the epidemiology of cardiovascular disease in pediatric chronic kidney disease, discusses risk factors and potential mechanisms of accelerated cardiovascular disease, reviews evidence of early manifestations of cardiovascular disease in pediatric chronic kidney disease, and briefly discusses prevention and treatment strategies.

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.

Monitoring kidney function and renal disease in children following transplant

This article reviews the currently available tools for measuring glomerular filtration rate (GFR) and early detection of chronic kidney disease in pediatric transplant recipients. GFR measurement remains the mainstay to detect renal dysfunction. Inulin clearance formed the earlier gold standard method to measure GFR. In current clinical practice, it has been replaced by nuclear medicine techniques (51Cr EDTA and 99Tc DTPA isotope clearance studies). GFR estimation based on surrogate markers allows more frequent GFR monitoring in a clinical setting. Serum creatinine has a low sensitivity to detect early renal dysfunction and its muscle mass dependency hampers its clinical utility. The Schwartz formula accounts for age-dependent muscle changes in children, but requires center-specific constants. Cystatin C offers the advantage of a constant production and a higher sensitivity in diagnosing renal dysfunction. Microalbuminuria has been an established screening tool in diabetic renal disease. It offers the advantage of detecting underlying renal damage even before a decrease in GFR. Its diagnostic value in other conditions needs evaluation. Hypertension is known to accelerate the progression of chronic kidney disease. A 24-h ambulatory blood pressure is a useful tool to diagnose hypertension, to quantify blood pressure load and to characterize nocturnal blood pressure dipping. GFR scans, serum creatinine and cystatin C form the cornerstone of currently used tools to evaluate kidney dysfunction.

Outcome after renal transplantation in children from native and immigrant families in Austria

Renal transplantation is the therapy of choice for children with end-stage renal disease (ESRD). Ethnicity affects the transplant survival rates substantially, but there has been no European academic evaluation of the effects of immigration on the pediatric renal transplantation outcome. The aim of this study was to compare the outcomes of renal transplantation between the children of immigrant families and the children of native families at the pediatric nephrology unit of the Medical University of Vienna, Austria. We conducted a retrospective study on all children who underwent renal transplantation at our center between January 1997 and June 2005. The patients were separated into two groups according to their immigration backgrounds. During the time frame of our study, 59 children underwent a total of 63 transplantations. Of these children, 42 were from native Austrian and 17 were from first-generation immigrant families. We analyzed the demographic data and outcome parameters for each of the 59 patients. We found no difference in patient and graft survival rates or long-term function between native and immigrant children. The two groups were also comparable in the rates of acute rejection episodes, 24-h blood pressure, and growth velocity. Living donor source had a positive influence on graft function (p=0.06), 24-h blood pressure (p=0.05), and growth velocity (p=0.02) only in the immigrant group. Our retrospective analysis shows no influence of the migration status on the patient or graft outcome, but we did find that immigrant children benefitted more than native children from living donation as opposed to deceased donation. To explain this fact, biological, heath-economical, psychosocial, and cultural background aspects must be investigated.

Hypertension after renal transplantation

Hypertension is a common and serious complication after renal transplantation. It is an important risk factor for graft loss and morbidity and mortality of transplanted children. The etiology of posttransplant hypertension is multifactorial: native kidneys, immunosuppressive therapy, renal-graft artery stenosis, and chronic allograft nephropathy are the most common causes. Blood pressure (BP) in transplanted children should be measured not only by casual BP (CBP) measurement but also regularly by ambulatory BP monitoring (ABPM). The prevalence of posttransplant hypertension ranges between 60% and 90% depending on the method of BP measurement and definition. Left ventricular hypertrophy is a frequent type of end-organ damage in hypertensive children after transplantation (50-80%). All classes of antihypertensive drugs can be used in the treatment of posttransplant hypertension. Hypertension control in transplanted children is poor; only 20-50% of treated children reach normal BP. The reason for this poor control seems to be inadequate antihypertensive therapy, which can be improved by increasing the number of antihypertensive drugs. Improved hypertension control leads to improved long-term graft and patient survival in adults. In children, there is a great potential for antihypertensive treatment that could also result in improved graft and patient survival.

Long-term outcome of pediatric renal transplantation: the Norwegian experience in three eras 1970-2006

During the years 1970-2006, 251 renal transplantations were performed in 178 children in Norway. The proportion of LD was 84%. Transplantations were performed preemptively in 52%. Pretransplant dialysis time was median three months. Structural abnormalities and hereditary renal disorders constituted 69% of end-stage renal diseases, 29% were caused by glomerulopathies and other acquired disorders and 2% of unknown cause. Patient survival rates were 94.2, 93.5, and 84.4% at five, 10, and 20 yr, respectively. The most frequent cause of death was infections followed by cardiovascular events. For recipients of living donor grafts (n = 149), survival of first transplant was 82, 68.8, and 45.1% at five, 10, and 20 yr, respectively, and was significantly higher than for recipients of deceased donor organs (n = 29; log rank, p = 0.008). The only significant predictor for better transplant survival when modeled with multiple regression analysis adjusted for pretransplant dialysis, diagnosis, donor age, sex and immunosuppressive era, was the use of LD compared with DD (HR = 2.1, 95% CI [1.1-4.0], p = 0.02). The acute rejection rate declined significantly from 61.5% in 1970-1982 to 14.5% in 2000-2006 (log rank, p = 0.002). It remains to be seen whether the reduction in acute rejection rate and present immunosuppressive therapy will have a positive impact on long-term graft survival in years to come.

Improved left ventricular mass index in children after renal transplantation

Left ventricular hypertrophy (LVH) is a risk factor for cardiovascular disease, and it is prevalent in children with end-stage renal disease (ESRD) and after renal transplantation (RTx) on cross-sectional studies. Our aim was to compare prospectively left ventricular mass index (LVMI) in children with ESRD, before and after RTx. Thirteen patients aged 1.5-15 years underwent echocardiogram prior to and at least 3 months after RTx, and again in the second year after transplantation. A control group consisted of children with ESRD who remained on dialysis. Systolic and diastolic blood pressure index decreased significantly over the study period only in the children who had undergone RTx. Mean LVMI in children with ESRD decreased from 45.4 +/- 12.6 g/m(2.7) to 34.9 +/- 10.4 g/m(2.7) after RTx (P = 0.001), but it remained unchanged in patients who remained on dialysis. The prevalence of LVH decreased from 54% to 8% (P = 0.03) after RTx. Systolic and diastolic blood pressure index were correlated with LVMI. Mean body mass index increased during the study period from 17.3 +/- 2.5 to 20 +/- 4.6 (P = 0.05); however, no correlation was found with LVMI. LVH in children with ESRD is potentially reversible after RTx, especially with good control of hypertension.

How to monitor renal function in pediatric solid organ transplant recipients

The aim is to review the tools for early detection of renal dysfunction after pediatric solid organ transplantation. Currently, the most widely used marker for detection of renal dysfunction involves measurement of GFR. Inulin clearance forms the "gold standard" method for measuring GFR; however, nuclear medicine methods ((51)Cr EDTA and (99)Tc DTPA isotope clearance studies) have replaced inulin clearance. The measurement of serum creatinine has a low sensitivity for the early detection of renal damage. The Schwartz formula using patient height and serum creatinine requires center-specific constants and has limitations associated with creatinine determination. These limitations may be overcome using a cystatin C-based GFR estimation. In diabetic nephropathy, and more recently in hemolytic uremic syndrome, microalbuminuria has been established as a useful screening tool for renal damage, while its predictive value in the transplantation setting needs to be established. All transplant recipients should be screened for hypertension. Early referral for ambulatory 24-h blood pressure monitoring and involvement of pediatric nephrologists should be considered. All pediatric solid organ transplant recipients receiving CNI should be screened regularly for high blood pressure and early evidence of renal damage using either GFR scans or cystatin C-based GFR estimations.

Cardiovascular complications of pediatric chronic kidney disease

Cardiovascular disease (CVD) mortality is a leading cause of death in adult chronic kidney disease (CKD), with exceptionally high rates in young adults, according to the Task Force on Cardiovascular Disease. Recent data indicate that cardiovascular complications are already present in children with CKD. This review summarizes the current literature on cardiac risk factors, mortality and morbidity in children with CKD.

Improved control of hypertension in children after renal transplantation: results of a two-yr interventional trial

Hypertension is a frequent complication in children after renal transplantation and the control of post-transplant hypertension is unsatisfactorily low. The aim of this prospective interventional study was to improve the control of hypertension in children after renal transplantation. Thirty-six children fulfilled the inclusion criteria (> or =6 months after transplantation and no acute rejection in the last three months). BP was measured using ABPM. Hypertension was defined as mean ambulatory BP > or =95th-centile for healthy children and/or using antihypertensive drugs. The study intervention consisted of using intensified antihypertensive drug therapy - in children with uncontrolled hypertension (i.e., mean ambulatory BP was > or =95th centile in treated children), antihypertensive therapy was intensified by adding new antihypertensive drugs to reach goal BP <95th centile. ABPM was repeated after 12 and 24 months. Daytime BP did not change significantly after 12 or 24 months. Night-time BP decreased from 1.57 +/- 1.33 to 0.88 +/- 0.84 SDS for systolic and from 1.10 +/- 1.51 to 0.35 +/- 1.18 SDS for diastolic BP after 24 months (p < 0.05). The number of antihypertensive drugs increased from 2.1 +/- 0.9 to 2.7 +/- 0.8 drugs per patient (p < 0.05), this was especially seen with the use of ACE-inhibitors (increase from 19% to 40% of children, p < 0.05). In conclusion, this interventional trial demonstrated that, in children after renal transplantation, the control of hypertension, especially at night-time, can be improved by increasing the number of antihypertensive drugs, especially ACE-inhibitors.

Left ventricular hypertrophy in pediatric kidney transplant recipients: long-term follow-up study

Cross-sectional studies indicate that LVH, known cardiovascular risk factor, is frequent in pediatric patients post-kidney transplant. We performed a retrospective longitudinal analysis of echocardiographic data collected in children and adolescents who received kidney transplant from 1998 to 2003. The first echo was performed at a median time post-transplant of 14 months in 47 children; a second echo (echo 2) was carried out at a median time of 33 months in 31 and a third echo (echo 3) was performed at a median time of 49 months in 14 children. LVH was defined as LV mass index >/=95th percentile for children. LVH was present in echo 1 in 25 (54%) subjects. Systolic blood pressure (p = 0.02) and BMI (p = 0.02) independently predicted the LVH seen in echo1 in multivariate logistic regression. In 14 subjects with three consecutive echocardiograms LVM index significantly decreased from echo 1 to echo 2 and from echo 1 to echo3 (p < 0.05), but no significant changes were observed between echo 2 and echo 3. The overall prevalence of LVH remained unchanged but its severity significantly decreased during the follow-up. The results of the study suggest that despite regression of LVM index overtime-pediatric patients post-kidney transplant are at continuous risk for developing cardiovascular disease.

Predominance of nocturnal hypertension in pediatric renal allograft recipients

Hypertension is common in children with end-stage renal disease who have undergone renal transplantation. We performed ambulatory blood pressure monitoring (ABPM) in renal allograft recipients who were on stable maintenance immunosuppressive medications and were more than six months post-transplant. Echocardiographic measurement of left ventricular mass index (LVMI) was obtained at the time of ABPM. Twenty-nine children with a mean age of 14.8 yr (8-18 yr) were evaluated 4.3 yr (0.6-12.8 yr) after deceased donor (n = 13) or living donor (n = 16) transplantation. BP levels were higher during sleep compared with when awake using the 95th percentile to standardize mean BP for each period: mean BP was expressed as a standard deviation score (SDS) for each time period, awake vs. sleep: systolic (s) BP SDS were 0.43 +/- 1.3 vs. 1.29 +/- 1.2 (p < 0.001) and diastolic (d) BP SDS were 0.04 +/- 1.3 vs. 1.34 +/- 1.2 (p < 0.001). Significant differences between awake and sleep BP were also confirmed using the mean BP for each period expressed as a BPI. Hypertension (HTN) during sleep was more common than awake HTN. Based upon BPI, 21% had sHTN when awake compared with 48% during sleep and 7% had dHTN when awake compared with 41% during sleep (p < 0.05). Based upon mean BP load, 38% had sHTN when awake compared with 55% during sleep and 21% demonstrated dHTN when awake compared with 52% during sleep (p < 0.05). Left ventricular mass (LVM) was abnormally increased in six of 17 children (35%); LVM was not correlated with BP. Children prescribed angiotensin converting enzyme inhibitors or angiotensin II receptor blockers (ACEi/ARB) had significantly lower systolic BP compared with those on calcium channel blocking agents (CCB). Mean sSDS was -0.11 +/- 1.1 in those children on ACEi/ARB compared with 1.6 +/- 1.2 in those on CCB (p = 0.02): sSDS during sleep was significantly lower in the ACEi/ARB group compared with CCB (0.70 +/- 1.1 vs. 2.0 +/- 1.1, p = 0.04). Isolated nocturnal HTN is more common than daytime HTN among clinically stable pediatric renal allograft recipients. Detection and treatment of nocturnal HTN in pediatric allograft recipients could potentially affect graft survival.

Left ventricular hypertrophy and arterial wall thickening in children with essential hypertension

OBJECTIVE

Our aim was to determine the prevalence of left ventricular hypertrophy (LVH) and increased intima-media thickness (IMT) in Caucasian children with newly diagnosed, untreated essential hypertension (EH).

PARTICIPANTS

Our study cohort consisted of 72 children with EH (mean age: 14.5 years; range: 5-18 years). The control groups consisted of 103 age-matched, healthy children.

METHODS

We evaluated the left ventricular mass (LVM), intima-media thickness in the carotid (cIMT) and superficial femoral (fIMT) arteries, 24-h ambulatory blood pressure, and biochemical cardiovascular risk factors.

RESULTS

Of the hypertensive children examined, 41.6% had LVM above the 95th percentile, and 13.2% had LVM above 51 g/m2.7. Of the hypertensive subjects, the cIMT was above 2 SDS of normal values in 38.8%, and the flMT was above 2 SDS of normal values in 17.5%. Patients with LVM above 51 g/m2.7 had a higher birth weight than other patients. LVM, cIMT, and fIMT correlated with 24-h SBP and pulse pressure; LVM also correlated with homocysteine and serum uric acid concentrations. fIMT correlated with low Aprotein A1 (ApoA1), higher ApoB and C reactive protein, and daily sodium excretion. Step-wise regression analysis revealed that serum uric acid and higher birth weight were predictors for LVM, pulse pressure was a predictor for cIMT, and ApoB was a predictor for fIMT.

CONCLUSIONS

A significant number of adolescents with EH already had cardiovascular damage at diagnosis. LVM and markers of arterial injury correlate with SBP, biochemical, and perinatal cardiovascular risk factors. Serum uric acid and higher birth weight are predictors of LVM.

Control of hypertension in children after renal transplantation

The aim of this cross-sectional single-center study was to investigate the efficacy of hypertension control in children who underwent transplantation using ambulatory blood pressure (BP) monitoring, and to determine the risk factors associated with poor control of hypertension. Thirty-six children fulfilled the inclusion criteria. The mean age was 13.9+/-4.4 yr; the mean time after renal transplantation was 2.7+/-2.4 yr (0.5-10.1). Hypertension was defined as a mean ambulatory BP > or =95th centile for healthy children and/or requiring antihypertensive drugs. Hypertension was regarded as controlled if the mean ambulatory BP was <95th centile in children already on antihypertensive drugs, or uncontrolled if the mean ambulatory BP was > or =95th centile in treated children. Hypertension was present in 89% of children. Seventeen children (47%) had controlled hypertension, and 14 (39%) had uncontrolled hypertension. One child (3%) had untreated hypertension, and only four children (11%) showed normal BP without antihypertensive drugs. The efficacy of hypertensive control was 55% (17 of 31 children on antihypertensive drugs had a BP<95th centile), i.e. 45% of treated children still had hypertension. Children with uncontrolled hypertension had significantly higher cyclosporine doses (6.1 vs. 4.3 mg/kg/day, p=0.01) and tacrolimus levels (9.2 vs. 6.1 microg/L, p<0.05), and there was a tendency toward use of lower number of antihypertensive drugs (2.0 vs. 1.5 drugs/patient, p=0.06) and lower use of angiotensin-converting enzyme (ACE) inhibitors (7 vs. 35%, p=0.09) and diuretics (29 vs. 59%, p=0.14) than in children with controlled hypertension. In conclusion, nearly 90% of our children after renal transplantation are hypertensive and the control of hypertension is unsatisfactorily low. The control of hypertension could be improved by increasing the number of prescribed antihypertensive drugs, especially ACE inhibitors, and diuretics, or by using higher doses of currently used antihypertensives.