Ambulatory blood pressure monitoring in pediatric renal transplantation

Epidemiology, Risk Factors, and Clinical Outcomes of AKI in Pediatric Hematopoietic Stem Cell Transplant Patients

Key Points

The cumulative incidence of AKI diagnosis post–hematopoietic stem cell transplantation was 12.9%. Calcineurin inhibitor use was associated with the highest cumulative incidence, 21.6%, after hematopoietic stem cell transplantation. Patients with AKI with hypertension/hypertensive disease had a 30-day survival probability of 63.9% (hazard ratio, 4.86, 95% confidence interval, 3.58 to 6.60). Patients with AKI were 2.5 times more likely to experience composite hospitalization and/or mortality at 30 days. Of patients who developed AKI, dialysis dependence has nearly tripled since 2014.

Background

AKI is a common complication in pediatric patients undergoing hematopoietic stem cell transplantation (HSCT), with a reported prevalence ranging from 68% to 84%. Few multicenter pediatric studies comprehensively assess the epidemiologic associations and clinical outcomes associated with AKI development.

Methods

An observational, retrospective analysis was conducted using an aggregated electronic health record data platform. The study population consisted of pediatric patients (age <18 years) who underwent HSCT over a 20-year period. The study groups consisted of patients with an encounter diagnosis of AKI (n =713) and those without AKI (n =4455). Both groups were propensity matched for age, sex, race, prior cancer diagnosis, and other comorbidities. End points were incidence, mortality risk, clinical outcomes, and prevalence of dialysis dependence. Competing risks analysis, Cox proportional hazard analyses, Kaplan–Meier survival curves, and incidence/prevalence rates were calculated.

Results

After matching, 688 patients were identified. Cumulative incidence of AKI diagnosis post-HSCT was 13.7%. Hypertensive disease, calcineurin inhibitors, and vancomycin were the most prevalent risk factors for AKI, with calcineurin inhibitors showing the highest cumulative incidence (21.6%). Patients with AKI with hypertensive disease had a survival probability of 63.9% at 30 days, followed by calcineurin inhibitors (64.4%) and vancomycin (65.9%). Patients with AKI were 1.7 times more likely to experience composite hospitalization and/or mortality at 30 days. At 365 days post-HSCT, patients with AKI had higher rates of all-cause emergency department visits, intensive care unit admissions, and mechanical ventilation compared with non-AKI. Of patients who developed AKI, the prevalence of dialysis dependence has nearly tripled since 2014.

Conclusions

The findings highlight a strong association between specific risk factors, such as hypertension, calcineurin inhibitor use, and vancomycin use, with increased mortality and adverse clinical outcomes in patients with AKI after HSCT. These results emphasize the need for preventative actions such as 24-hour BP monitoring and discontinuation of potential nephrotoxic medications.

Masked Hypertension in Healthy Children and Adolescents: Who Should Be Screened?

PURPOSE OF REVIEW

The goal is to review masked hypertension (MH) as a relatively new phenomenon when patients have normal office BP but elevated out-of-office BP. Firstly, it was described in children in 2004. It has received increased attention in the past decade.

RECENT FINDINGS

The prevalence of MH in different pediatric populations differs widely between 0 and 60% based on the population studied, definition of MH, or method of out-of-office BP measurement. The highest prevalence of MH has been demonstrated in children with chronic kidney disease (CKD), obesity, diabetes, and after heart transplantation. In healthy children but with risk factors for hypertension such as prematurity, overweight/obesity, diabetes, chronic kidney disease, or positive family history of hypertension, the prevalence of MH is 9%. In healthy children without risk factors for hypertension, the prevalence of MH is very low ranging 0-3%. In healthy children, only patients with the following clinical conditions should be screened for MH: high-normal/elevated office BP, positive family history of hypertension, and those referred for suspected hypertension who have normal office BP in the secondary/tertiary center.

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.

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.

Follow-Up of Blood Pressure, Arterial Stiffness, and GFR in Pediatric Kidney Transplant Recipients

Pediatric renal transplant recipients (RTx) were studied for longitudinal changes in blood pressure (BP), arterial stiffness by pulse wave velocity (PWV), and graft function.

Patients and Methods: 52 RTx patients (22 males) were included; office BP (OBP) and 24 h BP monitoring (ABPM) as well as PWV were assessed together with glycemic and lipid parameters and glomerular filtration rate (GFR) at 2.4[1.0–4.7] (T₁) and 9.3[6.3–11.8] years (T₂) after transplantation (median [range]).

Results: Hypertension was present in 67 and 75% of patients at T₁ and T₂, respectively. Controlled hypertension was documented in 37 and 44% by OBP and 40 and 43% by ABPM. Nocturnal hypertension was present in 35 and 30% at T₁ and T₂; 24 and 32% of the patients had masked hypertension, while white coat hypertension was present in 16 and 21% at T₁ and T₂, respectively. Blood pressure by ABPM correlated significantly with GFR and PWV at T₂, while PWV also correlated significantly with T₂ cholesterol levels. Patients with uncontrolled hypertension by ABPM had a significant decrease in GFR, although not significant with OBP. Anemia and increased HOMAi were present in ~20% of patients at T₁ and T₂.

Conclusion: Pediatric RTx patients harbor risk factors that may affect their cardiovascular health. While we were unable to predict the evolution of renal function based on PWV and ABPM at T₁, these risk factors correlated closely with GFR at follow-up suggesting that control of hypertension may have an impact on the evolution of GFR.

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).

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.

Steroid withdrawal improves blood pressure control and nocturnal dipping in pediatric renal transplant recipients: analysis of a prospective, randomized, controlled trial

BACKGROUND

Variable effects of steroid minimization strategies on blood pressure in pediatric renal transplant recipients have been reported, but data on the effect of steroid withdrawal on ambulatory blood pressure and circadian blood pressure rhythm have not been published so far.

METHODS

In a prospective, randomized, multicenter study on steroid withdrawal in pediatric renal transplant recipients (n = 42) on cyclosporine, mycophenolate mofetil, and methylprednisolone, we performed a substudy in 28 patients, aged 11.2 ± 3.8 years, for whom ambulatory blood pressure monitoring (ABPM) data were available.

RESULTS

In the steroid-withdrawal group, the percentage of patients with arterial hypertension, defined as systolic and/or diastolic blood pressure values recorded by ABPM > 1.64 SDS and/or antihypertensive medication, at month 15 was significantly lower (35.7%, p = 0.002) than in controls (92.9%). The need of antihypertensive medication dropped significantly by 61.2% (p < 0.000 vs. control), while in controls, it even rose by 69.3%. One year after steroid withdrawal, no patient exhibited hypertensive blood pressure values above the 95th percentile, compared to 35.7% at baseline (p = 0.014) and to 14.3% of control (p = 0.142). The beneficial impact of steroid withdrawal was especially pronounced for nocturnal blood pressure, leading to a recovered circadian rhythm in 71.4% of patients vs. 14.3% at baseline (p = 0.002), while the percentage of controls with an abnormal circadian rhythm (35.7%) did not change.

CONCLUSIONS

Steroid withdrawal in pediatric renal transplant recipients with well-preserved allograft function is associated with less arterial hypertension recorded by ABPM and recovery of circadian blood pressure rhythm by restoration of nocturnal blood pressure dipping.

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.

Importance of ambulatory blood pressure monitoring in the diagnosis and prognosis of pediatric hypertension

The prevalence of high blood pressure (BP) at pediatric age has increased progressively, one of the causes of which is obesity. However, the dominant etiology in this age group is renal and/or cardiovascular pathology. Ambulatory blood pressure monitoring (ABPM) is the method of choice for the diagnosis of hypertension, especially in children at high cardiovascular risk. Its use is limited to children from five years of age. Choosing appropriate cuff size is key to obtaining correct blood pressure. The main indication for ABPM is to confirm the diagnosis of hypertension. It also allows the diagnosis of white coat hypertension (which may represent an intermediate stage between the normotensive phase and hypertension), or masked hypertension, associated with progression to sustained hypertension and left ventricular hypertrophy (LVH). Children with isolated nocturnal hypertension should be considered as having masked hypertension. BP load is defined as the percentage of valid measurements above the 95th percentile for age, gender, and height. Values above 25-30% are pathological and those above 50% are predictive of LVH. ABPM correlates with target organ damage, particularly LVH and renal damage. It is useful in the differentiation of secondary hypertension, since these children show higher BP load and less nocturnal dipping, and confirmation of response to therapy. Thus ABPM allows the diagnosis and classification of hypertension, provides cardiovascular prognostic information and identifies patients with intermediate phenotypes of hypertension.

Factors associated with cardiovascular target organ damage in children after renal transplantation

BACKGROUND

Cardiovascular disease is the second-most common cause of death in pediatric renal transplant recipients. The aim of this study was to evaluate subclinical cardiovascular target organ damage defined as the presence of arterio- and atherosclerotic lesions and cardiac remodeling and to analyze contributing risk factors in a large cohort of children after renal transplantation (RT).

METHODS

A total of 109 children aged 13.1 ± 3.3 years who had undergone RT at one of three German transplant centers were enrolled in this study. Patients had been transplanted a mean of 5.5 (±4.0) years prior to being enrolled in the study. Anthropometric data, laboratory values and office- and 24-h ambulatory blood pressure monitoring (ABPM) were evaluated. Cardiovascular target organ damage was determined through non-invasive measurements of aortic pulse wave velocity (PWV), carotid intima-media thickness (IMT) and left ventricular mass (LVM).

RESULTS

Elevated PWV or IMT values were detected in 22 and 58% of patients, respectively. Left ventricular hypertrophy was found in as many as 43% of patients. The prevalence of uncontrolled or untreated hypertension was 41%, of which 16% of cases were only detected by ABPM measurements. In the multivariable analysis, higher diastolic blood pressure, everolimus intake and lower estimated glomerular filtration rate were independently associated with high PWV. Higher systolic blood pressure and body mass index were associated with elevated LVM.

CONCLUSIONS

Our results showed an alarming burden of cardiovascular subclinical organ damage in children after RT. Hypertension, obesity, immunosuppressive regimen and renal function emerged as independent risk factors of organ damage. Whereas the latter is not modifiable, the results of our study strongly indicate that the management of children after RT should focus on the control of blood pressure and weight.

Hypertension in children with end-stage renal disease

This review summarizes current data on the epidemiology, pathophysiology, and treatment of hypertension (HTN) in children with end-stage renal disease (ESRD). Worldwide prevalence of ESRD ranges from 5.0 to 84.4 per million age-related population. HTN is present in 27-79% of children with ESRD, depending on the modality of renal replacement therapy and the exact definition of hypertension. Ambulatory BP monitoring has been recommended for the detection of HTN and evaluation of treatment effectiveness. HTN in dialyzed patients is mostly related to hypervolemia, sodium overload, activation of the renin-angiotensin-aldosterone system (RAAS) and sympathetic nervous system, impaired nitric oxide synthesis, reduced vitamin D levels, and effects of microRNA. In children undergoing chronic dialysis therapy, important factors include optimization of renal replacement therapy and preservation of residual renal function, allowing reduction of volume- and sodium-overload, along with appropriate drug treatment, particularly with calcium channel blockers, RAAS inhibitors, and loop diuretics.

Arterial hypertension in children with hemolytic uremic syndrome after kidney transplantation

The development of arterial hypertension after KTX is a well-known complication. HUS is a systemic disease associated with arterial hypertension during long-term follow-up. Our goal was to report on the severity of arterial hypertension after KTX in patients with typical and atypical HUS. We analyzed the course of 197 patients with HUS, of which 22 (n = 10 with typical HUS; n = 12 with atypical HUS) developed ESRF and received KTX as renal replacement therapy. We analyzed data from 1766 casual BP and 85 24-h ABPM measurements. In addition, we evaluated the used antihypertensive strategy. Comparison between the two patient groups revealed that patients with atypical HUS had significantly higher casual SBP-SDS and DBP-SDS values after KTX despite similar intensity of antihypertensive treatment. These data were supported by analysis of ABPM profiles showing comparable results for the interval 1-5 yr after KTX. Patients with atypical HUS had a greater severity of arterial hypertension despite similar treatment strategies and intensity of treatment. Our observation, even though in a small cohort, supports recent genetic studies showing arterial hypertension closely associated with HUS-causing mutations in patients with atypical HUS.

Ambulatory blood pressure monitoring is recommended in the clinical management of children with a solitary functioning kidney

BACKGROUND

Children with a solitary functioning kidney are at increased risk of developing chronic kidney disease. Hypertension may be an early indicator of renal dysfunction in these patients. We determined blood pressure (BP) profiles of children with a solitary functioning kidney by using ambulatory BP monitoring (ABPM).

METHODS

To assess the occurrence with (pre)hypertension, we compared ABPM to office BP measurement in 47 children with a solitary functioning kidney. None of the subjects used antihypertensive agents or had been hypertensive during previous clinical visits.

RESULTS

Mean age of study subjects was 12.7 (±3.3) years. Hypertension was identified in ten (21 %) subjects with ABPM, whereas only two (4 %) children were hypertensive during office BP measurement (p < 0.01). Fifteen (32 %) children had an ABPM standard deviation (SD) value ≥90th percentile versus six (13 %) subjects based on office BP measurement (p = 0.051). Although 24-h ABPM SD scores were higher in the congenital type than in the acquired type of solitary functioning kidney (p ≤ 0.01), the proportions of subjects with 24-h ABPM hypertension were similar between groups (congenital 25 % versus acquired 16 %; p = NS).

CONCLUSIONS

Based on ABPM, one in five children with a solitary functioning kidney has hypertension. As the majority of these subjects were not hypertensive during office BP measurements, ABPM should be considered in the clinical management of solitary functioning kidney patients.

Recent developments in kidney transplantation in children

PURPOSE OF REVIEW

Renal transplantation in childhood is a well established procedure with excellent short-term outcomes. However, waiting times for transplantation are still relatively long if living donation cannot be performed, and long-term outcomes after transplantation have not significantly improved during the last decade.

RECENT FINDINGS

This review describes alternative modalities to improve donation rates such as en bloc kidney transplantation from young donors, ABO-incompatible transplantation and kidney paired donation. This review also deals with long-term post-transplant morbidities, such as follows: first, medication side-effects (metabolic syndrome, cardiovascular disease) and with the benefits of steroid and calcineurin inhibitor drug minimization; second, the deleterious impact of viral infections and their management and third, chronic antibody-mediated rejection, its therapeutic and prevention possibilities.

SUMMARY

Donor shortage and long-term morbidities, after transplantation, are still relevant issues in paediatric renal transplantation medicine. Significant research and efforts have been made to advance the field and create novel approaches for improvement of transplantation rates and post-transplant graft or patient survival. These modalities are to be established in the routine setting.

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.

An observational cohort study of the effect of hypertension on the loss of renal function in pediatric kidney recipients

BACKGROUND

Post-transplant hypertension impacts negatively on renal graft survival. Our primary objective was to analyze the effect of hypertension on the glomerular filtration rate (GFR) slope.

METHODS

All clinical charts of children who underwent renal transplantation since the introduction of the routine use of ambulatory blood pressure monitoring (ABPM) were reviewed. Eligibility criteria for inclusion were measurement of GFR at 3 months, at 1 year post-transplant, and thereafter at yearly intervals; ABPM performed annually after transplantation; and functioning graft for a minimum of 2 years.

RESULTS

Sixty-eight (39 males) of 79 patients, aged 9.1±5.3 years, met the inclusion criteria. The mean follow-up was 6.2±2.8 years. Twenty-four patients had normotension or controlled hypertension throughout their follow-up (normotensive group). Forty-four patients had hypertension or noncontrolled hypertension at some point(s) during the follow-up period (hypertensive group). GFR slope was -1.6ml/min/1.73 m(2) per year (95% confidence interval (CI = -3.7 to 0.4) in the normotensive group and -2ml/min/1.73 m(2) per year (95% CI = -3 to -1.1) in the hypertensive group (P = 0.42). There was no difference between groups with regard to the change in GFR values from 3 months to 1 year and to last control (P = 0.87). At most recent control, the overall prevalence of controlled hypertension was 78.2% (95% CI = 63.6-89.1).

CONCLUSIONS

Although the results of our study are encouraging, they need to be confirmed in a larger prospective study using the same post-transplant follow-up protocol.