Ambulatory blood pressure monitoring after renal transplantation in children

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.

Isolated nocturnal hypertension in pediatric kidney transplant recipients

BACKGROUND

Isolated nocturnal hypertension (INH) is defined as nighttime hypertension in the setting of normal daytime blood pressure (BP), diagnosed by ambulatory BP monitoring (ABPM).

METHODS AND RESULTS

Hypertension affects 60%-80% of pediatric kidney transplant recipients, and INH is the most common type of ambulatory hypertension. INH is associated with an increased prevalence of hypertension-mediated target organ damage such as left ventricular hypertrophy in adults and in pediatric kidney transplant recipients.

CONCLUSION

Ambulatory BP monitoring should be performed annually in all pediatric kidney transplant recipients to diagnose hypertension phenotypes that are not detectable by office BP such as masked hypertension, white-coat hypertension, or INH. Isolated nocturnal hypertension in pediatric transplant patients requires study as a treatment target.

Should ACE inhibitors or calcium channel blockers be used for post-transplant hypertension?

Arterial hypertension in renal transplant recipients warrants antihypertensive treatment. The preferable choice of antihypertensives that should be used in patients after kidney transplantation remains a matter of debate; however, calcium channel blockers (CCB) and angiotensin-converting enzyme inhibitors (ACEI) are currently the most commonly used antihypertensives. This educational review summarizes the current evidence about the effects of these two classes of medications in transplant recipients. Several studies have demonstrated that both classes of drugs can reduce blood pressure (BP) to similar extents. Meta-analyses of adult randomized controlled trials have shown that graft survival is improved in patients treated with ACEIs and CCBs, and that CCBs increase, yet ACEIs decrease, graft function. Proteinuria is usually decreased by ACEIs but remains unchanged with CCBs. In children, no randomized controlled study has ever been performed to compare BP or graft survival between CCBs and ACEIs. Post-transplant proteinuria could be reduced in children along with BP by ACEIs. The results of the most current meta-analyses recommend that due to their positive effects on graft function and survival, along with their lack of negative effects on serum potassium, CCBs could be the preferred first-line antihypertensive agent in renal transplant recipients. However, antihypertensive therapy should be individually tailored based on other factors, such as time after transplantation, presence of proteinuria/albuminuria, or hyperkalemia. Furthermore, due to the difficulty in controlling hypertension, combination therapy containing both CCBs and ACEIs could be a reasonable first-step therapy in treating children with severe post-transplantation hypertension.

Restoration of nocturnal blood pressure dip and reduction of nocturnal blood pressure with evening anti-hypertensive medication administration in pediatric kidney transplant recipients: A pilot randomized clinical trial

Non-dipping and nocturnal hypertension are commonly found during ABPM in pediatric kidney transplant recipients. These entities are independently associated with increased cardiovascular disease risk in adults. Kidney transplant recipients aged 5-21 years with eGFR > 30 mL/min/1.73 m² and ABPM demonstrating non-dipping status and normal daytime BP were randomized to intervention (short acting BP medication added in the evening) or control (no medication change) in this pilot, randomized, open-label, blinded end-point clinical trial. ABPM, echocardiography, and PWV were performed at baseline, 3 months, and 6 months. The trial included 17 intervention and 16 control participants. Conversion to dipper status occurred in 53.3% vs 7.7% (P = .01) at 6 months for intervention and controls, respectively. Systolic dip was greater in the intervention group compared to controls (10.9 ± 4.5 vs 4.2 ± 4.6, P = .001), and average systolic nighttime BP was significantly lower in the intervention group (106 ± 8.3 vs 114.9 ± 9.5 mm Hg, P = .01) at 6 months. There were no significant differences in LVMI, PWV, or eGFR between groups. Within-group changes in the intervention group demonstrated improvements in non-dippers, dipping, systolic nighttime BP and nighttime BP load. Restoration of nocturnal dip and improvement in nocturnal BP were observed in the population following chronotherapy. Future studies are needed with larger sample sizes over a longer period of time to delineate the long-term effect of improved nocturnal dip on target organ damage.

Sex and age as determinants for high blood pressure in pediatric renal transplant recipients: a longitudinal analysis of the CERTAIN Registry

BACKGROUND

High prevalence of arterial hypertension is known in pediatric renal transplant patients, but how blood pressure (BP) distribution and control differ between age groups and whether sex and age interact and potentially impact BP after transplantation have not been investigated.

METHODS

This retrospective analysis included 336 pediatric renal transplant recipients (62% males) from the Cooperative European Pediatric Renal Transplant Initiative Registry (CERTAIN) with complete BP measurement at discharge and 1, 2 and 3 years post-transplant.

RESULTS

At discharge and 3 years post-transplant, arterial hypertension was highly prevalent (84% and 77%); antihypertensive drugs were used in 73% and 68% of the patients. 27% suffered from uncontrolled and 9% from untreated hypertension at 3 years post-transplant. Children transplanted at age < 5 years showed sustained high systolic BP z-score and received consistently less antihypertensive treatment over time. Younger age, shorter time since transplantation, male sex, higher body mass index (BMI), high cyclosporine A (CSA) trough levels, and a primary renal disease other than congenital anomalies of the kidney and urinary tract (CAKUT) were significantly associated with higher systolic BP z-score. Sex-stratified analysis revealed a significant association between high CSA and higher systolic BP in older girls that likely had started puberty already. An association between BP and estimated glomerular filtration rate was not detected.

CONCLUSIONS

BP control during the first 3 years was poor in this large European cohort. The description of age- and sex-specific risk profiles identified certain recipient groups that may benefit from more frequent BP monitoring (i.e. young children) or different choices of immunosuppression (i.e. older girls).

Clinical value of ambulatory blood pressure in pediatric patients after renal transplantation

Hypertension is a highly prevalent co-morbidity in pediatric kidney transplant recipients. Undertreated hypertension is associated with cardiovascular complications and negatively impacts renal graft survival. Thus, the accurate measurement of blood pressure is of the utmost importance for the correct diagnosis and subsequent management of post-renal transplant hypertension. Data derived from the general population, and to a lesser extent from the pediatric population, indicates that ambulatory blood pressure monitoring (ABPM) is superior to blood pressure measurements taken in the clinical setting for the evaluation of true mean blood pressure, identification of patients requiring antihypertensive treatment, and in the prediction of cardiovascular outcome. This Educational Review will discuss the clinical value of ABPM in the identification of individual blood pressure phenotypes, i.e., normotension, new-onset hypertension, white-coat hypertension, masked hypertension, controlled blood pressure, and undertreated/uncontrolled hypertension in pediatric kidney transplant recipients. Finally, we examine the utility of performing repeated ABPM for treatment monitoring of post-renal transplant hypertension and on surrogate markers related to relevant clinical cardiovascular outcomes. Taken together, our review highlights the clinical value of the routine use of ABPM as a tool for identifying and monitoring hypertension in pediatric kidney transplant recipients.

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.

Ambulatory Blood Pressure Monitoring and Echocardiographic Findings in Renal Transplant Recipients

Hypertension is common in renal transplant recipients (RTRs). Ambulatory blood pressure (BP) monitoring (ABPM) is important in diagnosing hypertension and diurnal BP variation. The authors set out to compare office BP and ABPM measurements to determine diurnal pattern and to evaluate echocardiographic findings in RTRs. ABPM and office BP measurements were compared in 87 RTRs. Echocardiographic evaluation was performed for each patient. The correlations between office and 24-hour ABPM were 0.275 for mean systolic BP (P=.011) and 0.260 for mean diastolic BP (P=.017). Only 36.8% had concordant hypertension between office BP and ABPM, with a masked hypertension rate of 16.1% and white-coat effect rate of 24.1%. Circadian BP patterns showed a higher proportion of nondippers (67.8%). Left ventricular mass index was increased in 21.8% of all recipients. There was a significant but weak correlation between office BP and ABPM.

Hypertension in children after renal transplantation

BACKGROUND

Hypertension (HT) is a common and serious complication following renal transplantation in children, and an important risk factor for cardiovascular morbidity and mortality. This study evaluated the clinical characteristics of HT in children after renal transplantation.

METHODS

Twenty-four children who were followed up at least 6 months after renal transplantation were enrolled in the study. From the clinical records, demographic and laboratory data, casual blood pressure (BP) measurement, ambulatory BP monitoring (ABPM), medication, and left ventricular mass index (LVMI) at echocardiogram were documented.

RESULTS

Mean age at time of transplantation was 12.6 ± 3.0 years and mean follow-up period was 19.6 ± 15.8 months. HT was detected in 21 children (87.5%) after renal transplantation. Twelve patients (50%) had HT both before and after transplantation and nine (38%) had HT only after transplantation. HT developed in 67% within the first week and in 95% within the first month. All hypertensive children had night-time HT and no child had isolated daytime HT. The efficacy of HT control was 42%. Median LVMI in patients with HT after renal transplantation was 42.3 g/m(2.7).

CONCLUSIONS

Severe HT, an important complication, was frequently seen in the early period after renal transplantation. Predominance of nocturnal HT and the lack of isolated daytime HT after transplantation underline the importance of ABPM. ABPM should be performed regularly in the first year after transplantation, not only for diagnosis but also for evaluation of HT control.

Evaluation of hypertension by ambulatory blood pressure monitoring in children with solitary kidney

In this study, we aimed to investigate the blood pressure (BP) profile in children with a unilateral functioning solitary kidney (UFSK). A group of 49 patients between the ages of 5 and 18 years, and 30 healthy controls between the ages of 6 and 16 years were investigated. Gender, weight, height and body mass index (BMI) of patients and controls were recorded. BP profile was determined by ambulatory BP monitoring (ABPM). We have observed a higher risk of hypertension compared with healthy children. Also, masked hypertension is more frequently in the patients group and white-coat hypertension was observed in the control group. The mean night-time systolic BP (SBP) load (p = 0.01) and 24-h diastolic BP (DBP) load (p = 0.008) of children with multicystic dysplastic kidney (MCDK) was significantly higher than the healthy group. The mean night-time SBP load (p = 0.001) of children with unilateral renal agenesis (URA) and 24-h DBP load (p = 0.003) of children with unilateral atrophic or hypoplastic kidney were significantly higher than healthy group. We showed that the children with a solitary kidney had increased risk of hypertension. ABPM reflects the BP profile more precisely than casual BP measurement and it can be used to evaluate white-coat and masked hypertension in children with a solitary kidney.

Blood pressure profiles 5 to 10 years after transplant in pediatric solid organ recipients

Arterial hypertension is a major risk factor for cardiovascular disease after solid organ transplantation, emphasizing the need for blood pressure (BP) monitoring. The authors studied 24-hour ambulatory BP monitoring (ABPM) parameters (index, load, dipping) and their predictive value with regard to hypertension as well as correlations with graft function and metabolic parameters such as obesity and dyslipidemias. The ABPM profiles of 111 renal, 29 heart, and 13 liver transplant recipients were retrospectively analyzed 5 to 10 years after transplant (median 5.1 years). The BP profiles among the different transplant groups were similar. The BP index and load were abnormal especially at nighttime and the nocturnal BP dipping was often blunted (in 49% to 83% of the patients). The BP variables were found to be equally valued when assessing hypertension. BP load of 50% instead of 25% seems to be a more adequate cutoff value. The BP variables correlated poorly with the metabolic parameters and kidney function. Antihypertensive medication did not notably change the ABPM profile in renal transplant recipients. Hypertension, including nocturnal hypertension, is present in children receiving solid organ transplant, underlining the importance of use of ABPM in the follow-up of these patients.

Post-transplant hypertension in pediatric kidney transplant recipients

BACKGROUND

The aim of the study was to investigate the prevalence of post-transplant hypertension (HT) and to assess the blood pressure (BP) of transplanted children with possible risk factors.

METHODS

Office and ambulatory blood pressure measurements were performed for each patient.

RESULTS

Twenty-nine patients were included in the study, including 13 patients with newly diagnosed untreated HT according to the results of ambulatory blood pressure monitoring (ABPM). Fourteen patients were on antihypertensive medication, but only in five of these patients was the HT under control; nine patients receiving antihypertensive drugs had uncontrolled HT. Of the 29 patients, two had normotension without any antihypertensive drug(s). Standard deviation scores (SDS) of the nocturnal diastolic BP of the ABPM were positively correlated with the prednisolone dosage per kilogram (p = 0.013, r = 0.45) and negatively correlated with the time period after transplantation (p = 0.024, r = -0.41). Similarly, the SDS of the 24-h diastolic BP was positively correlated with the prednisolone dosage per kilogram (p = 0.006, r = 0.50) and negatively correlated with the time period after transplantation (p = 0.016, r = -0.44). Patients with alternate-day steroid treatment had lower nocturnal systolic (p = 0.016), nocturnal diastolic (p = 0.001) and 24-h diastolic (p = 0.008) SDS when compared to those receiving daily steroid medication.

CONCLUSION

The prevalence of HT among children after renal transplantation was high among our patient cohort, and steroids had direct impact on nocturnal and diastolic BP.

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.

Systemic arterial hypertension in children following renal transplantation: prevalence and risk factors

BACKGROUND

Control of blood pressure (BP) following renal transplantation may improve allograft and patient survival. Our aims were (i) to describe the distribution of BP and the prevalence of systolic and/or diastolic hypertension in children over the first 5 years following renal transplantation and (ii) to evaluate clinical risk factors and centre-specific factors associated with hypertension in this population.

METHODS

We conducted a retrospective case note review of all current paediatric kidney transplant patients in the UK, with data collected at 6 months, 1, 2 and 5 years following transplantation in subjects with hypertension (systolic and/or diastolic BP > 95th > ) and non-hypertensive subjects BP ≤ 95th > .

RESULTS

In total, 27.3% (117/428), 27.6% (118/428), 26.0% (95/365) and 25.6% (50/195) of the patients were hypertensive (systolic and/or diastolic BP > 95th > ) at 6 months, 1, 2 and 5 years following transplantation, respectively. A total of 58.4% of the patients at 6 months, 52.8% at 1 year, 48.2% at 2 years and 48.2% at 5 years were receiving anti-hypertensive therapy, of whom 31.6-36.6% remained hypertensive. When subjects were identified as being hypertensive, on anti-hypertensive medication or had untreated hypertension (systolic and/or diastolic BP > 95th > ), 66.4, 61.0, 56.4 and 55.9% of patients were hypertensive at 6 months, 1, 2 and 5 years, respectively. In a multivariate model, odds ratios for systolic hypertension were 4.16 (deceased versus living donor), 2.65 (lowest versus highest quartile of height z-score) and 2.07 (if on anti-hypertensive; yes versus no). There was significant variation in prevalent rates of hypertension between centres (P < 0.0001) that remained significant (P = 0.003) after adjustment for all the factors in the multivariate model.

CONCLUSIONS

Control of BP after kidney transplantation remains sub-optimal in paediatric centres in the UK. Just over 25% of patients remain hypertensive 5 years following transplantation. Significant differences between centres remain unexplained and may reflect differences in assessment and management of hypertension.

Importance of ambulatory blood pressure monitoring in adolescent hypertension

There has been a steady increase in the prevalence of adolescent hypertension in recent years. In order to prevent target organ damages, it is important to determine the group of hypertensive adolescents. If repeatedly elevated blood pressure values are observed, with special emphasis on white coat hypertension, which is particularly frequent at this age, ambulatory blood pressure monitoring is highly recommended before pharmacological treatment is started. In addition, performing ambulatory blood pressure monitoring is recommended with target organ damage, resistance to therapy, and suspicion of secondary hypertension. The results of the widely available, simple-to-use device are easy to reproduce.

Blood pressure profile in renal transplant recipients and its relation to diastolic function: tissue Doppler echocardiographic study

Hypertension is a common complication after renal transplantation and is associated with increased risk of cardiovascular disease. The aim of the current study was to investigate the diurnal blood pressure pattern and its relation to structural and functional cardiac changes in renal transplant recipients. Sixty-six stable renal transplant patients (34 female, 32 male), aged 7 to 25 years (mean 17.4±4.3 years) were enrolled in this study. Cardiac function assessed by tissue Doppler echocardiography and blood pressure measurement performed using both the ambulatory and the casual method. Hypertension was demonstrated in 57% of recipients by the casual method and in 75.7% by ambulatory blood pressure monitoring (ABPM). The efficacy of BP control among patients on antihypertensive drugs was 60%. The prevalence of non-dipping was 73%. There was significant inverse correlation between systolic or diastolic day-time or night-time BP index and post-transplant duration (p<0.001, r=-0.386), but no correlation between ABP parameters and BMI, gender, and eGFR. There was a significant relationship between all ABP parameters and left ventricular mass index (LVMI) (p=0.025-0.007, r=0.28-0.38). LVMI was significantly higher in hypertensive than in normotensive cases (p=0.034). There was no difference in diastolic function between hypertensive and normotensive patients or between patients with and without left ventricular hypertrophy (LVH). In conclusion, our study showed the advantage of ABPM over the casual method of diagnosis of hypertension. LVH is common in transplant patients and is likely associated with arterial hypertension. Hypertension and LVH cannot differentiate transplant patients with diastolic malfunction.

Cardiorespiratory fitness is a marker of cardiovascular health in renal transplanted children

Children with renal transplants (TX) are at increased risk of cardiovascular (CV) disease. Study objectives were to assess the level of cardiorespiratory fitness (CR fitness) and daily physical activity (PA) in renal TX children and adolescents in relation to traditional cardiovascular risk factors. Laboratory testing included assessment of CR fitness by treadmill exercise testing (VO(2peak)), 24-h ambulatory blood-pressure (ABPM) measurement, oral glucose tolerance test (OGTT), anthropometrics and measurement of lipid levels. PA was self-reported by questionnaire. Twenty-two TX patients with a median (range) age 14.5 (9-18) years were tested. Median V0(2peak) was 66% (36-97) of the expected values compared with controls. Nineteen (86%) children reported <60 min of daily moderate to vigorous physical activity (MVPA). Sixteen (73%) were hypertensive and 8 (34%) were overweight or obese. Four children fulfilled the criteria for a metabolic syndrome. Children with at least 2 of the 3 metabolic risk factors (hypertension, overweight, and glucose intolerance, n=7) achieved significantly lower VO(2peak) compared with those with one or none of these factors (median V0(2peak) 45% and 73% of the expected values respectively, p=0.003). Renal TX children and adolescents have severely impaired CR fitness and PA. Reduced CR fitness was associated with the clustering of CV risk factors. Routine counseling for increased PA is strongly recommended.

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.

High prevalence of the metabolic syndrome and associated left ventricular hypertrophy in pediatric renal transplant recipients

The goal of this study was to estimate prevalence of the metabolic syndrome and its association with cardiac abnormalities in children with kidney transplant. A multi-center retrospective review of demographic, clinical, laboratory, and echocardiographic parameters at time of and at one-yr post-transplant was conducted in 234 pediatric recipients between 2000 and 2006. Eighty-eight patients (37.6%) met criteria for metabolic syndrome. Among 55 overweight patients, 40% had metabolic syndrome. Among 51 obese patients, 74.5% had metabolic syndrome. A total of 181 (71.0%) patients had complete data at both time points: prevalence of metabolic syndrome at time of transplant was 18.8%, compared with 37.0% at one-yr post-transplant (p < 0.0001). Among 147 patients without metabolic syndrome at time of transplant, 41 (27.9%) had developed metabolic syndrome by one-yr post-transplant. A total of patients from four centers had routine echocardiogram at one-yr post-transplant. LVH was significantly more common in those with metabolic syndrome (55%) than in those without (32%) (OR 2.6, 95% CI 1.2-5.9).

IN CONCLUSION

metabolic syndrome is common at time of pediatric kidney transplant, and prevalence rises sharply at one-yr post-transplant. The presence of metabolic syndrome is strongly associated with LVH in these patients.

[Importance of ambulatory blood pressure monitoring in adolescent hypertension]

The prevalence of adolescent hypertension is increasing. The national epidemiological study found 2.5% prevalence, while it is 4.5% according to the newest international survey. Repeated casual blood pressure measurements, but not ambulatory blood pressure monitoring is needed for the diagnosis of adolescent hypertension on the basis of the presently available European guideline. At the last decade growing evidence came into light for ambulatory blood pressure monitoring in adolescence. These data show better correlation with end-organ damages than casual measurements. In patients with hypertension diagnosed based on repeated casual blood pressure measurements, 24-hour monitoring showed normal blood pressure in 21-47%, so this is the rate of white coat hypertension. Masked hypertension can also be diagnosed with the help of this method, which has a prevalence of 7-11%. We can also get useful data for secondary forms of hypertension. Until the appearance of the new European guidelines, more frequent use of ambulatory blood pressure monitoring is affordable. The confirmation of the diagnosis based on elevated casual blood pressure data is important. Ambulatory blood pressure monitoring is suggested in cases suspicious for white coat or masked hypertension, in cases of target organ damages or therapy resistant hypertension. Before administration of pharmaceutical therapy in adolescence hypertension - according to author's opinion - ambulatory blood pressure monitoring is absolutely necessary.

Comparison of ambulatory blood pressure reference standards in children evaluated for hypertension

OBJECTIVE

The purpose of this study was to systematically compare methods for standardization of blood pressure levels obtained by ambulatory blood pressure monitoring (ABPM) in a group of 111 children studied at our institution.

METHODS

Blood pressure indices, blood pressure loads and standard deviation scores were calculated using the original ABPM and the modified reference standards. Bland-Altman plots and kappa statistics for the level of agreement were generated.

RESULTS

Overall, the agreement between the two methods was excellent; however, approximately 5% of children were classified differently by one as compared with the other method.

CONCLUSION

Depending on which version of the German Working Group's reference standards is used for interpretation of ABPM data, the classification of the individual as having hypertension or normal blood pressure may vary.

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.

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.

Blood pressure control in hypertensive pediatric renal transplants: role of repeated ABPM following transplantation

BACKGROUND

Hypertension in pediatric renal transplants is a widespread condition associated with high mortality risk in early adult life. Ambulatory blood pressure monitoring (ABPM) was found to be superior to office blood pressure (BP) in identifying true hypertensive and responders to treatment. The aim of this study was to investigate the role of repeated ABPM, performed at yearly intervals following transplantation, in the assessment and decision-making processes of post-transplant hypertension.

METHODS

Thirty-seven recipients (23 males; aged 10.5 +/- 4.3 years) who were followed for 4.3 +/- 2.2 years (range 2-9) after transplantation were eligible for analysis. The mean follow-up time between the baseline (1 year post-transplantation) and the most recent ABPM examination was 3.3 +/- 2.2 years (range 1-8).

RESULTS

Throughout the follow-up period, antihypertensive therapy was either started or intensified in 27 recipients. These interventions were decided based on ABPM results obtained on 40 of 44 occasions. At last follow-up, 24 of 29 treated hypertensive recipients displayed controlled BP. This figure was significantly higher compared to our historical hypertensive control recipients in whom ABPM was applied for the first time in treatment at 6 +/- 3.3 years (range 2-15) after transplantation, while therapeutic decisions were driven by office BP measurements (95 % confidence interval (95% CI) for the difference between proportions (80.6-32 %) 36-60 %, P = 0.001).

CONCLUSIONS

Our study shows that, in a population with high risk for hypertension, repeated ABPM may significantly help to improve BP control.

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.

Ambulatory blood pressure monitoring: what a pediatrician should know

PURPOSE OF REVIEW

Ambulatory blood pressure monitoring is a useful tool for the evaluation and management of hypertension in children and adolescents. This review provides a basic overview of ambulatory blood pressure monitoring and summarizes the most recent available knowledge regarding its use in the pediatric population.

RECENT FINDINGS

Evaluation and validation of ambulatory blood pressure monitoring equipment in children remains limited, although advances in the interpretation of results for this age group have been reported specifically in the area of circadian (24 h) and ultradian (<24 h) variability. Blood pressure is a dynamic phenomenon that varies not only with time but also with changing patient and environmental circumstances. Growing evidence regarding conditions identified when this variability is considered, specifically white coat and masked hypertension, suggests that office blood pressure measurement may not be a sufficient screening test for hypertension-related target-organ damage.

SUMMARY

Information regarding ambulatory blood pressure monitoring use in children is increasing, although due to its limitations and expense, it remains a tool primarily utilized by the pediatric sub-specialist.

ABPM vs office blood pressure to define blood pressure control in treated hypertensive paediatric renal transplant recipients

While 24-h ambulatory blood pressure monitoring (ABPM) is an established tool for monitoring antihypertensive therapy in adults, data in children are scarce. We retrospectively analysed whether office blood pressure (BP) is reliable for the diagnosis of BP control in 26 treated hypertensive paediatric renal transplants. Controlled office BP was defined as the mean of three replicate systolic and diastolic BP recordings less than or equal to the 95th age-, sex- and height-matched percentile on the three-outpatient visits closest to ABPM. Controlled ABPM was defined as systolic and diastolic daytime BP < or =95th distribution adjusted height- and sex-related percentile of the adapted ABPM reference. Eight recipients (30%) with controlled office BP were in fact categorized as having non-controlled BP by ABPM criteria. Overall, when office BP and ABPM were compared using the Bland and Altman method, the 95% limits of agreement between office and daytime values ranged from -12.6 to 34.1 mmHg for systolic and -23.9 to 31.7 mmHg for diastolic BP, and the mean difference was 10.7 and 3.9 mmHg respectively. Office readings miss a substantial number of recipients who are hypertensive by ABPM criteria. Undertreatment of hypertension could be avoided if ABPM is applied as an adjunct to office readings.

Utility of ambulatory blood pressure monitoring in children and adolescents

Diagnosis of hypertension is critically dependent on accurate blood pressure measurement. "Accurate" refers to carefully following the guidelines for blood pressure measurement laid out for children and adults to minimize observer and subject errors that commonly occur in clinical blood pressure measurement. Accurate blood pressure measurement is more important in children and adolescents as the misdiagnosis of hypertension may have a life-long adverse impact on insurability and employment. Automated blood pressure measurement offers multiple advantages in achieving high-quality blood pressure determinations by reducing observer errors. The most commonly used form of automated blood pressure measurement is 24-h ambulatory blood pressure measurement (ABPM). Information on ABPM in children has grown exponentially over the last decade. Normative data exists for diagnosis of hypertension in children using ABPM including a novel method for determining normal values with the LMS method. There is further information about the utility of different determinants of 24-h blood pressure such as dipping status, morning surge and blood pressure load. ABPM has been able to detect significant differences in blood pressure in many disease states in children including chronic renal failure, polycystic kidney disease, solitary functioning kidney, and after renal transplantation. Increasingly nonambulatory automated blood pressure determinations have been used in management of hypertension in children. Although nonambulatory automated readings lack information about nocturnal blood pressure or blood pressure during daily activity, studies have suggested that home automated blood pressure measurements are a helpful adjunct to the usual office blood pressure reading.

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.

The choice of threshold limits for pediatric ambulatory blood pressure monitoring influences clinical decisions

OBJECTIVES

Hypertension in children may be defined by blood pressure elevated above the 95th percentile according to sex and age. Population data for ambulatory blood pressure provide different age-related and sex-related threshold limits to office-derived data. We sought to determine whether, when using ambulatory blood pressure monitoring in a clinical setting, changing 95th percentile threshold limit sets from office-derived to ambulatory blood pressure-derived would lead to different diagnostic decisions.

METHODS

Three nephrologists who were blinded as to patient identity and limit setting method reported on 42 ambulatory blood pressure records from a mixed group of patients aged 5-18 years by using both office-derived threshold limits for the 95th centile of blood pressure and ambulatory blood pressure-derived limits. Decisions regarding the presence or absence of hypertension were compared for each patient according to the limit set.

RESULTS

Thirty-five (83%) patients were considered to be hypertensive when office-derived threshold limits were used and 20% (P=0.005) fewer records were reported as showing hypertension when ambulatory blood pressure-derived threshold limits were used. When ambulatory blood pressure limits were applied, there were fewer records with an awake systolic blood pressure load >50% (P=0.004) and the average awake systolic blood pressure load was significantly lower (P<0.001).

CONCLUSION

Ambulatory blood pressure normative data tend to provide higher blood pressure limits for age and sex. Consequently, when ambulatory blood pressure data are used to set threshold limits, clinical decisions based on ambulatory blood pressure may be different than when office limits are used. These findings demonstrate the importance of using the most appropriate limit sets to analyze ambulatory blood pressure and when interpreting ambulatory blood pressure-based research.

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.

Hypertension and ace gene insertion/deletion polymorphism in pediatric renal transplant patients

The objective of the present study was to define the risk factors for hypertension and to analyze the influence of insertion/deletion (I/D) polymorphism of the angiotensin-converting enzyme (ACE) on hypertension in pediatric renal transplant recipients. Twenty-six pediatric renal transplant recipients with stable renal function and treated with the same immunosuppression protocol were included in the study. Their mean age was 12.5 +/- 3.3 yr and mean time after transplantation was 38.5 +/- 39.8 month. Twenty-four hour ambulatory blood pressure monitoring (ABPM) was performed by SpaceLabs (90207) device. The I/D polymorphism of the ACE was determined by PCR and ACE serum level was analyzed by colorimetric method. Hypertension was present in 15 patients (57.7%) by causal blood pressure measurements and 19 patients (73.1%) by ABPM. Twenty-two patients (84.6%) were found to be non-dipper and eight of them had reverse dipping. Only time after transplantation (38 +/- 31 vs. 79 +/-49 month, p = 0.016) and cyclosporin A trough plasma levels (206 +/-78 vs. 119 +/- 83 ng/mL, p = 0.020) influenced the presence of hypertension by multiple logistic regression analysis. The distribution of genotypes were II = 2 (7.7%), ID = 8 (30.8%), DD = 16 (61.5%). There was no effect of ACE gene I/D polymorphism or serum ACE levels on hypertension prevalence and circadian variability of blood pressures. Hypertension was related to the time after transplantation and cyclosporin A levels. The ACE gene I/D polymorphism and serum ACE levels did not influence the blood pressure values or circadian variability of blood pressure among pediatric renal transplant patients.

Ambulatory blood pressure monitoring in children after renal transplantation

Arterial hypertension is a common complication in children after renal transplantation and the control of hypertension is often difficult. This retrospective investigates the prevalence and rate of control of hypertension using ambulatory blood pressure monitoring (ABPM) in 45 children (mean age 14.1 +/- 4.3 years, mean time after renal transplantation 2.2 +/- 2.7 years), all on cyclosporine or tacrolimus, azathioprine or mycophenolate mofetil plus daily steroids. The overall prevalence of hypertension was 82%. None of the transplanted children had normal blood pressure without antihypertensive therapy (ie, spontaneous normotension). Twenty percent of children had untreated hypertension, 18% had controlled hypertension, and 62% had uncontrolled hypertension. Prevalence of the nondipping phenomenon was 53%. The mean number of antihypertensive drugs (without diuretic monotherapy) in treated patients was 1.9 drugs per patient. The prevalence of arterial hypertension in children after renal transplantation is high and the control of hypertension is often unsatisfactorily low.

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

Cardiovascular events are among the most frequent causes for long-term morbidity and mortality in children after renal transplantation. The aim of this study was to analyze the effects of post-transplant changes in arterial hypertension, as assessed by 24-h ambulatory blood pressure measurement (ABPM), on myocardial architecture, as assessed by echocardiography. In a retrospective chart review analysis, 39 children were identified in whom 24-h ABPM and echocardiography had been assessed within a 3-month interval after a mean of 4 years post transplantation; 20 repeated pairs of measurements after a mean of 2 years of follow-up were available to analyze the longitudinal effects of post-transplant changes of blood pressure control on left ventricular mass index (LVMI). Arterial hypertension (59%) and left ventricular hypertrophy (50%) were highly prevalent in children after renal transplantation. Renal allograft function and number of antihypertensive medications, but not ABPM variables, were correlated with LVMI at the initial observation. However, at repeat assessment, a significant correlation between ABPM and LVMI was found. In the longitudinal assessment, left ventricular remodeling was dependent on change of dosage of cyclosporine and interval changes of blood pressure levels. Hence, control of blood pressure correlates with changes of LVMI in children with renal allografts. These results clearly underline the importance of blood pressure control for the maintenance of the myocardial architecture.

Blood pressure in the long-term follow-up of children with hemolytic uremic syndrome

The hemolytic uremic syndrome (HUS) is the most common cause of acute renal failure (ARF) in young children. Most patients recover from the acute phase of the illness but they may develop arterial hypertension(AH) after many years, even in the absence of signs of renal impairment during short-term follow-up. In this study, we performed casual blood pressure (BP) measurement, 24-h blood pressure monitoring (ABPM), and a Bruce walking treadmill study (ET) in 24 children (aged 5-15 years, 13 males, 11 females) with a history of HUS and normal renal function during follow-up (median 5.8 years, range 1.8-12.4 years). There were 22 children(91%) with prodromal diarrhea associated with HUS and 20 (83%) underwent dialysis during the acute illness. All children had normal casual BP measurement. Of 13 children (54%) with normal ABPM, 5 patients (38%) had an abnormal BP response during the ET study. There were 4 (58%) of the 7 patients with AH by ABPM (29%)and an abnormal BP response during ET. These findings suggest that ET could be a useful means of identifying children with a history of HUS that could be at risk of future AH even if they had normal renal function, casual BP, and ABPM during long-term follow-up. These results should be confirmed with a large prospective clinical study.

Pathomechanisms and the diagnosis of arterial hypertension in pediatric renal allograft recipients

Arterial hypertension is common in pediatric renal allograft recipients. While the causes are multifactorial, including chronic graft rejection, immunosuppressive therapy, and renal vascular disorders, the effect of hypertension on renal allograft function is detrimental. As in adults, if not treated early and aggressively, hypertension may lead to cardiovascular damage and graft failure. Pathophysiological changes in the arteries and kidney af-ter renal transplantation and the impact of receptor regulation have not been studied extensively in children. For identifying children with hypertension following renal transplantation casual blood pressure measurements do not accurately reflect average arterial blood pressure and circadian blood pressure rhythm. Ambulatory 24-h blood pressure monitoring should regularly be applied in trans-plant patients. The purpose of this review is to analyze pathophysiological aspects of risk factors for arterial hypertension and underline the importance of regular blood pressure monitoring and early therapeutic intervention.

Twenty-four-hour ambulatory blood pressure profiles in liver transplant recipients

Twenty-four-hour ambulatory blood pressure monitoring (ABPM) has proven to have better reproducibility than office blood pressure (BP) and is increasingly used for the study of hypertension in children and adolescents. The aim of our study was to assess 24-h BP profiles and to compare the results of office BP measurements with ABPM in stable liver transplant recipients transplanted before the age of 18 yr. ABPM was performed in 29 patients (nine males, 20 females), aged 3.9-24.8 yr (median 10.8 yr). The investigation was conducted 1.1-11.5 yr (median 5.1 yr) following transplantation. ABPM confirmed hypertension in one out of three office hypertensive patients. Seven patients (24%), whose office BP recordings were within the normotensive range, were reclassified as hypertensive. Non-dippers (n = 17), arbitrarily defined as patients with less than 10% nocturnal fall in BP, were similarly distributed among patients with ambulatory normotension and ambulatory hypertension (chi(2), p = 0.79). In addition, non-dippers showed a negative correlation between 24-h total urinary albumin excretion and both systolic and diastolic nocturnal decline in BP (Rho = -0.48, p < 0.05 and Rho = -0.86, p < 0.01, respectively). Our study found office BP readings to be poorly representative of 24-h BP profile. Larger studies are needed to confirm our observations as well as to determine whether routine BP measurements in the follow-up of paediatric liver transplant recipients should be based solely on office BP.

Hypertension and end-organ damage in pediatric renal transplantation

The prevalence of hypertension in pediatric patients with renal transplant (Tx) has not changed for the last three decades, remaining at 50-80%. Long-standing and uncontrolled hypertension is associated with the development of end-organ damage including allograft dysfunction, early cardiomyopathy and premature atherosclerosis. Aggressive treatment of elevated BP is an essential part of Tx care with the goal to delay graft failure and prevent the development of symptomatic cardiovascular disease in young recipients of renal Tx.

Abnormal carotid artery structure and function in children and adolescents with successful renal transplantation

BACKGROUND

Abnormal carotid artery compliance and increased intima-media thickness (IMT), markers of early atherosclerosis, are prevalent in adults with chronic kidney failure. However, little is known about the extent of these abnormalities in children after transplantation.

METHODS AND RESULTS

Thirty-one children (age, 14.5+/-4.1 years) with renal transplant (estimated glomerular filtration rate, 78.1+/-24.5 mL/min per 1.73 m2; range, 44 to 128 mL/min per 1.73 m2) and 33 age- and sex-matched control subjects had ultrasound of the carotid artery, echocardiography, and ambulatory blood pressure monitoring (transplant patients only). IMT was measured, and distensibility and stiffness parameter (beta) were calculated to assess carotid artery structure and function. The results were correlated with demographic, clinical, and biochemical variables. Compared with control subjects, children with transplant had higher IMT (P=0.03) and beta (P<0.0001) and lower distensibility (P<0.001). In multiple regression analysis, increased IMT in children who had received transplants was associated with higher mean office systolic blood pressure taken within 1 year before the study (R2=0.19, P=0.024) and receipt of >1 transplant (R2=0.16, P=0.02). Worse distensibility and beta were significantly associated with higher daytime systolic blood pressure load calculated from ambulatory blood pressure and receipt of cadaveric kidney. When number of antihypertensives was added to the models, only higher number of blood pressure medications independently predicted abnormal distensibility (R2=0.38, P=0.002) and beta (R2=0.25, P=0.016).

CONCLUSIONS

Carotid arteriopathy is present in children with successful renal transplant and is associated with hypertension. The results suggest that these children might be at risk for accelerated atherosclerosis and premature cardiovascular disease.

Predictors of progression in hypertensive renal disease in children

In hypertensive renal disease in children, several risk factors influence the development and the rate of progression of renal damage, including blood pressure levels, proteinuria, lipid disorders, and genetic differences. The impact of blood pressure on renal structures, the most important of the factors, depends not only on blood pressure levels, but also on the persistence of the blood pressure levels over time, mainly during the hours when the patient is resting or sleeping. Abnormal circadian variability is frequently observed in patients with renal damage, and nocturnal blood pressure reduction should be a major therapeutic objective to protect against a decline in renal function. Proteinuria is a guide for establishing targets and for monitoring treatment. It should be reduced as much as possible to obtain maximal renoprotective effect. The role of the other factors, such as lipid disorders and genetics, remains elusive.

Measurement and treatment of elevated blood pressure in the pediatric patient with chronic kidney disease

Hypertension, as in adults, is a frequent complication found in children with chronic kidney disease (CKD). Indeed, hypertension has now become one of the most prevalent chronic diseases of childhood. The most recent data available (2003) indicate that at least 38% of children with CKD in the United States are receiving antihypertensive therapy. Only recently has it been shown in children that hypertension, traditionally considered a marker for disease severity in children, is additionally a significant and independent risk factor for accelerated deterioration of kidney function and progression of CKD and a significant risk factor for cardiovascular disease. The following review outlines the differences and similarities of childhood versus adult hypertension with respect to measurement, diagnosis, treatment, and consequence in CKD. The definition of hypertension changes continually as a child grows with or without CKD. Despite numerous guidelines, the diagnosis of childhood hypertension continues to be based on epidemiologic data rather than evidence. For children, the current definition includes 2 categories: high normal, which is blood pressure (BP) between the 90th and 95th percentile, and hypertensive, which is BP above the 95th percentile. The evaluation of all hypertensive children should include a complete assessment of end-organ damage, including eyes, cardiovascular system (including blood vessels), kidneys, and nervous system. For children with CKD and end-stage renal disease (ESRD), a high percentage have left ventricular hypertrophy (LVH). The finding of end-organ damage or comorbidity (CKD, diabetes) in any child is an absolute indication for immediate pharmacologic therapy, whereas the presence of hypertension above the 95th percentile in children without CKD warrants initial intervention such as life style modification. The guidelines for measurement of BP in children with CKD are similar to those in children without CKD and include casual BP measurement, self-measured BP, and ambulatory BP monitoring. The recommendation for BP measurement in children is, when permitted, by auscultative method with a well-calibrated mercury manometer. Most casual BP measurements are performed with an automated oscillometric device whose validation has not been confirmed in children with CKD. The ambulatory BP monitor (ABPM) has 2 advantages: it significantly correlates with the presence of end-organ damage, and it identifies abnormal BP patterns that are frequently present in CKD patients, such as hypertension during the sleep period. An abnormal ABPM pattern can also be predictive of the development of end-organ damage. Treatment of hypertension in children, with and without CKD, is based on 3 factors: degree of BP elevation, the presence of cardiovascular risk factors, and the presence of end-organ damage. Additionally, the initial antihypertensive agent may be selected on available and age-appropriate formulations (eg, suspension and dosage selection). A physician treating a hypertensive child with CKD faces multiple challenges. They include selecting the convenience of available automated devices and the ABPM versus traditional auscultatory techniques upon which all normative standards have been based. Current research initiatives propose to develop pharmacokinetic and pharmacodynamics properties of antihypertensive medications and to study the effect of early intervention on end-organ damage.