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

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.

Prediction of lisinopril pediatric dose from the reference adult dose by employing a physiologically based pharmacokinetic model

Background

This study aimed to assess the pediatric lisinopril doses using an adult physiological based pharmacokinetic (PBPK) model. As the empirical rules of dose calculation cannot calculate gender-specific pediatric doses and ignores the age-related physiological differences.

Methods

A PBPK model of lisinopril for the healthy adult population was developed for oral (fed and fasting) and IV administration using PK-Sim MoBI® and was scaled down to a virtual pediatric population for prediction of lisinopril doses in neonates to infants, infants to toddler, children at pre-school age, children at school age and the adolescents. The pharmacokinetic parameters were predicted for the above groups at decremental doses of 20 mg, 10 mg, 5 mg, 2.5 mg, and 1.5 mg in order to accomplish doses producing the pharmacokinetic parameters, similar (or comparable) to that of the adult population. The above simulated pediatric doses were compared to the doses computed using the conventional four methods, such as Young’s rule, Clark’s rule, and weight-based and body surface area-based equations and the dose reported in different studies.

Results

Though the doses predicted for all subpopulations of children were comparable to those calculated by Young’s rule, yet the conventional methods overestimated the pediatric doses when compared to the respective PBPK-predicted doses. The findings of previous real time pharmacokinetic studies in pediatric patients supported the present simulated dose.

Conclusion

Thus, PBPK seems to have predictability potential for pediatric dose since it takes into consideration the physiological changes related to age and gender.

Effects of the strict control of blood pressure in pediatric renal transplant recipients-ESCORT trial

OBJECTIVES

Strict BP control can retard progression of CKD in children. This prospective 3-year randomized controlled trial is aimed to investigate whether strict BP control can retard progression of chronic allograft dysfunction.

METHODS

Twenty-three pediatric patients were randomly selected to the standard BP group (STAND, target 24-hour MAP 50-95th percentile, n = 11) or the intensified BP group (INTENS, target 24-hour MAP <50th percentile, n = 12). The primary endpoint was an annual reduction in eGFR (Schwartz formula, mL/min/1.73 m² /y), secondary graft survival, BP, proteinuria, and safety.

RESULTS

A total of 21 children (age at entry 11.2 (range 6.2-16.8) years) completed the study, with 73% of children in INTENS and 70% of children in STAND group reached their goal BP. Ambulatory indexed 24-hour MAP decreased significantly in INTENS group (from 0.94 (range 0.86-1.17) to 0.85 (range 0.79-1.01, P < 0.01)) but not in STAND group (from 0.93 (range 0.85-1.07) to 0.90 (range 0.84-1.01)). Proteinuria did not change significantly in either group (22.1 mg/mmol creatinine to 15.3 in STAND group vs 25.7 to 11.8 in INTENS group). The annual reduction in eGFR did not differ between the INTENS and STAND groups (-1.9 mL/min/1.73 m² /y (range +6.4 to -14.3) vs -0.9 (range +4.0 to -8.5)).

CONCLUSION

This first randomized controlled trial on strict BP control has demonstrated that strict BP control is feasible in 73% of children but the strict BP control does not lead to retardation of graft function decline in comparison with standard BP control. However, the results need to be interpreted with caution keeping the major limitation of the study, that is, small sample size in mind.

Early Effects of Renal Replacement Therapy on Cardiovascular Comorbidity in Children With End-Stage Kidney Disease: Findings From the 4C-T Study

BACKGROUND

The early impact of renal transplantation on subclinical cardiovascular measures in pediatric patients has not been widely investigated. This analysis is performed for pediatric patients participating in the prospective cardiovascular comorbidity in children with chronic kidney disease study and focuses on the early effects of renal replacement therapy (RRT) modality on cardiovascular comorbidity in patients receiving a preemptive transplant or started on dialysis.

METHODS

We compared measures indicating subclinical cardiovascular organ damage (aortal pulse wave velocity, carotid intima media thickness, left ventricular mass index) and evaluated cardiovascular risk factors in 166 pediatric patients before and 6 to 18 months after start of RRT (n = 76 transplantation, n = 90 dialysis).

RESULTS

RRT modality had a significant impact on the change in arterial structure and function: compared to dialysis treatment, transplantation was independently associated with decreases in pulse wave velocity (ß = -0.67; P < 0.001) and intima media thickness (ß = -0.40; P = 0.008). Independent of RRT modality, an increase in pulse wave velocity was associated with an increase in diastolic blood pressure (ß = 0.31; P < 0.001). Increasing intima media thickness was associated with a larger increase in body mass index (ß = 0.26; P = 0.003) and the use of antihypertensive agents after RRT (ß = 0.41; P = 0.007). Changes in left ventricular mass index were associated with changes in systolic blood pressure (ß = 1.47; P = 0.01).

CONCLUSIONS

In comparison with initiating dialysis, preemptive transplantation prevented further deterioration of the subclinical vascular organ damage early after transplantation. Classic cardiovascular risk factors, such as hypertension and obesity are of major importance for the development of cardiovascular organ damage after renal transplantation.

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.

Is Blood Pressure Improving in Children With Chronic Kidney Disease? A Period Analysis

Uncontrolled hypertension in children with chronic kidney disease (CKD) has been identified as one of the main factors contributing to progression of CKD and increased risk for cardiovascular disease. Recent efforts to achieve better blood pressure (BP) control have been recommended. The primary objective of this analysis was to compare BP control over 2 time periods among participants enrolled in the CKiD study (Chronic Kidney Disease in Children). Casual BP and 24-hour ambulatory BP monitor data were compared among 851 participants during 2 time periods: January 1, 2005, through July 1, 2008 (period 1, n=345), and July 1, 2010, through December 31, 2013 (period 2, n=506). Multivariable logistic regression to model the propensity of a visit record being in period 2 as a function of specific predictors was performed. After controlling for confounding variables (age, sex, race, socioeconomics, CKD duration, glomerular filtration rate, proteinuria, body mass index, growth failure, and antihypertensives), no significant differences were detected between time periods with respect to casual BP status (prehypertension: 15% versus 15%; uncontrolled hypertension: 18% versus 17%; P=0.87). Analysis of ambulatory BP monitor data demonstrated higher ambulatory BP indices, most notably masked hypertension in period 2 (36% versus 49%; P<0.001). Average sleep BP index (P<0.05) and sleep BP loads (P<0.05) were higher in period 2. Despite publication of hypertension recommendations and guidelines for BP control in patients with CKD, this study suggests that hypertension remains undertreated and under-recognized in children with CKD. This analysis also underscores the importance of routine ambulatory BP monitor assessment in children with CKD.

Ambulatory Blood Pressure Control in Children and Young Adults After Kidney Transplantation

BACKGROUND

Ambulatory blood pressure (BP) monitoring (ABPM) is the preferred method to characterize BP status, and its use in kidney transplant recipients is increasing. Data on longitudinal ambulatory BP (ABP) trends in pediatric and young adult kidney transplant recipients are limited.

METHODS

Retrospective review of a large cohort of children and young adults following kidney transplantation and evaluation of their ABP status over time and its associations with any patient and clinical characteristics.

RESULTS

Two hundred and two patients had baseline ABPM available for analysis, and 123 of them had a follow up (median time 2.3 years) ABPM. At the time of follow up, more patients were treated for hypertension (80% vs. 72%, P = 0.02), and less patients had ambulatory hypertension (36% vs. 54%, P = 0.005), uncontrolled or untreated, compared with baseline, with 45% of all patients classified as having controlled hypertension (compared to 26% at baseline, P = 0.002). Prevalence of ambulatory hypertension decreased only in patients who were less than 18 years old at baseline. High baseline mean 24-hour systolic BP was independently associated with persistent hypertension.

CONCLUSIONS

In young kidney transplant recipients followed by ABPM, the prevalence of ambulatory hypertension decreases over time, mainly due to the increased number of patients with controlled hypertension.

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.

Masked hypertension and allograft function in pediatric and young adults kidney transplant recipients

Masked hypertension is a common complication of pediatric kidney transplantation. While office hypertension is known to be associated with worse short- and long-term graft function, the role of masked hypertension in allograft dysfunction is not clear. We conducted a retrospective cross-sectional analysis of 77 consecutive pediatric kidney transplant recipients who had routine 24-h ambulatory blood pressure monitoring with the aims to estimate the prevalence of masked hypertension and examine its association with allograft function. Masked hypertension was defined as a 24-h systolic or diastolic blood pressure load ≥25%. Twenty-nine percent of patients had masked hypertension. Patients with masked hypertension had significantly lower allograft function estimated using the creatinine-based Schwartz-Lyon formula, a cystatin C-based formula, and combined cystatin C and creatinine-based formulas than patients with normal blood pressure (all p values <0.05). In a multivariable analysis, masked hypertension remained independently associated with worse allograft function after adjustment for age, sex, race, time post-transplant, rejection history, antihypertensive treatment, and hemoglobin level. We conclude that in young kidney transplant recipients, masked hypertension is common and is associated with worse allograft function. These results support the case for routine ambulatory blood pressure monitoring as the standard of care in these patients to detect and treat masked hypertension.

Single-center assessment of nutritional counseling in preventing excessive weight gain in pediatric renal transplants recipients

Post-transplantation obesity is a common complication that is associated with a higher risk for decreased allograft function and hypertension. However, the role of diet intervention on reducing post-transplantation obesity is relatively unknown. We investigated the clinical relevance of dietary counseling on the prevalence of overweight/obesity during the first two yr following renal transplantation. The computerized patient records of 42 recipients (31 males) aged 6.3 ± 4.8 yr at transplantation were reviewed. All patients systematically underwent yearly dietary assessment/counseling (motivational interviewing technique) and measurement of renal function and ABPM. At transplantation, 14.2% of patients were overweight/obese, which increased to 42.8% by two yr post-transplantation (p = 0.004). The majority of patients experienced a significant increase in BMI SDS during the first six months post-transplantation that remained sustained throughout the duration of the follow-up period (p = 0.001). By two yr post-transplantation, there were no observable differences between patients classified as having normal BMI or being overweight/obese with regard to renal function and controlled hypertension. The application of yearly tailored dietary assessment/counseling had a poor effect on preventing post-transplantation weight gain, suggesting the need for more comprehensive interventions to reduce post-transplant obesity.

Blood Pressure, Proteinuria, and Renal Function Decline: Associations in a Large Community-Based Population

BACKGROUND

Hypertension and proteinuria are risk factors for adverse renal outcomes in patients with chronic kidney disease. This study investigated the associations of blood pressure and proteinuria on renal function in a community-based population.

METHODS

We analyzed data from a nationwide database of 141,514 subjects who participated in the annual "Specific Health Check and Guidance in Japan" checkup in 2008 and 2010. The study subjects were aged between 29 and 74 years, and the cohort comprised 40% men. We examined relationships between blood pressure levels, proteinuria at baseline, and the 2-year change in the estimated glomerular filtration rate (eGFR), which was determined using the Japanese equation.

RESULTS

After adjusting for possible confounders, the change in the eGFR was inversely correlated with systolic blood pressure (SBP), but not diastolic blood pressure (DBP), at baseline, irrespective of the presence of proteinuria. Compared with the lowest SBP sixtile (≤118mm Hg), eGFRs declined significantly at SBPs ≥ 134mm Hg in subjects with proteinuria, while eGFRs declined significantly at SBPs ≥ 141mm Hg in those without proteinuria. At the same SBPs, renal function decline was faster and the risk for incident renal insufficiency was higher in subjects with proteinuria compared with those without proteinuria.

CONCLUSIONS

This study showed that a difference in SBP, but not DBP, is independently associated with a rapid eGFR decline in the general Japanese population, and that the association of SBP on the decline of renal function was greater in subjects with proteinuria compared with those without proteinuria.

Oscillometric casual blood pressure normative standards for Swedish children using ABPM to exclude casual hypertension

BACKGROUND

Casual blood pressure (CBP) is considered a reliable proxy for cardiovascular health. Although the auscultatory technique is the reference standard method for measuring CBP, oscillometric devices are increasingly being used in children. We sought to establish oscillometric CBP normative standards for Swedish children.

METHODS

Cross-sectional oscillometric CBP readings were obtained by the Welch Allyn Spot Vital Signs 420 monitor and measured according to the International Guidelines' recommendations. Participants with elevated oscillometric CBP levels underwent verification by the auscultatory method. Ambulatory blood pressure monitoring (ABPM) was used to exclude casual hypertension. Data on 1,470 (772 males) apparently healthy Swedish schoolchildren aged 6-16 years were analyzed and sex-specific reference charts normalized to age or height were constructed.

RESULTS

Systolic and diastolic CBP values were significantly higher with age, height, height standard deviation score (SDS), body mass index (BMI), and BMI SDS. Gender differences for systolic CBP were present starting from age of 15 years and revealed significantly higher values in boys than in girls, whereas for diastolic CBP, the differences were apparent at the age of 12 years, with higher values in girls. Increased BMI and BMI SDS were positively associated with CBP levels. Positive parental history of hypertension turned out to be a risk factor for higher systolic and diastolic CBP across all ages.

CONCLUSIONS

Our normative standard for CBP can be used for blood pressure screening and control programs in Swedish children. The use of ABPM should be considered to confirm the diagnosis of casual hypertension.

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.