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

Cardiovascular disease risk factors and lifestyle modification strategies after pediatric kidney transplantation: what are we dealing with, and what can we target?

Kidney transplantation in pediatric patients can lead to partial improvement of some of the cardiometabolic parameters that increase the risk for cardiovascular disease (CVD) in patients with chronic kidney disease. However, even after restoration of kidney function, transplant recipients remain at risk for CVD due to the continual presence of traditional and non-traditional risk factors, including the side effects of immunosuppression and chronic inflammation. This educational review describes the prevalence of CVD risk factors in pediatric kidney transplant recipients and presents available evidence for therapeutic lifestyle changes and other non-pharmacologic strategies that can be used to improve traditional and modifiable CVD risk factors. Although trial-grade evidence for interventions that improve CVD in pediatric kidney transplant recipients is limited, potential strategies include lowering dietary sodium and saturated fat intake and increasing physical activity levels. Intensive follow-up may help patients achieve guideline-recommended goals for reducing their overall CVD risk.

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.

Arterial stiffness and blood pressure increase in pediatric kidney transplant recipients

BACKGROUND

Pulse wave velocity (PWV) is a measure of arterial stiffness. We investigated PWV and blood pressure (BP) to determine to what extent BP changes contribute to arterial stiffness, and secondly, to identify influencing factors on BP in children after kidney transplantation.

METHODS

Seventy children ≥ 2.5 years post-transplantation with at least two PWV measurements were included. Changes of systolic (Δ SBP) and diastolic BP (Δ DBP) were classified into "stable/decreasing," "1-10 mmHg increase," and " > 10 mmHg increase." Linear mixed modeling for PWV z-score (PWVz) adjusted either for Δ SBP or Δ DBP was performed. An extended dataset with monthly entries of BP, immunosuppression, and creatinine was obtained in 35 participants over a median of 74 months to perform linear mixed modeling for SBP and DBP.

RESULTS

PWVz increased with a rate of 0.11/year (95% CI 0.054 to 0.16). Compared to participants with stable BP, those with 1-10-mmHg SBP and DBP increase showed a higher PWVz of 0.59 (95% CI 0.046 to 1.13) and 0.86 (95% CI 0.43 to 1.30), respectively. A > 10-mmHg BP increase was associated with an even higher PWVz (SBP β = 0.78, 95% CI 0.22 to 1.34; DBP β = 1.37, 95% CI 0.80 to 1.94). Female sex and participants with lower eGFR showed higher PWVz. In the extended analysis, DBP was positively associated with cyclosporin A and everolimus trough levels.

CONCLUSIONS

A higher increase of PWV is seen in patients with greater BP increase, with higher cyclosporin A and everolimus trough levels associated with higher BP. This emphasizes the role of BP as a modifiable risk factor for the improvement of cardiovascular outcome after transplantation. A higher resolution version of the Graphical abstract is available as Supplementary information.

Echocardiogram screening in pediatric dialysis and transplantation

Transthoracic echocardiography is commonly used to identify structural and functional cardiac abnormalities that can be prevalent in childhood chronic kidney failure (KF). Left ventricular mass (LVM) increase is most frequently reported and may persist post-kidney transplant especially with hypertension and obesity. While systolic dysfunction is infrequently seen in childhood chronic KF, systolic strain identified by speckle tracking echocardiography has been frequently identified in dialysis and it can also persist post-transplant. Echocardiogram association with long-term outcomes has not been studied in childhood KF but there are many adult studies demonstrating associations between increased LVM, systolic dysfunction, strain, diastolic dysfunction, and cardiovascular events and mortality. There has been limited study of interventions to improve echocardiogram status. In childhood, improved blood pressure has been associated with better LVM, and conversion from hemodialysis to hemodiafiltration has been associated with better diastolic and systolic function. Whether long-term cardiac outcomes are also improved with these interventions is unclear. Echocardiography is a well-established technique, and regular use in childhood chronic KF seems justified. A case can be made to extend screening to include speckle tracking echocardiography and intradialytic studies in high-risk populations. Further longitudinal studies including these newer echocardiogram modalities, interventions, and long-term outcomes would help clarify recommendations for optimal use as a screening tool.

Promoting cardiovascular health post-transplant through early diagnosis and adequate management of hypertension and dyslipidemia

Despite correction of underlying solid organ failure by transplantation, pediatric transplant recipients still have increased mortality rates compared to the general pediatric population, in part due to increased cardiovascular risk. In particular, pediatric kidney and non-kidney transplant recipients with chronic kidney disease have significant cardiovascular risk that worsens with declining kidney function. Biomarkers associated with future cardiovascular risk such as casual and ambulatory hypertension, dyslipidemia, vascular stiffness and calcification, and left ventricular hypertrophy can be detected throughout the post-transplant period and in patients with stable kidney function. Among these, hypertension and dyslipidemia are two potentially modifiable cardiovascular risk factors that are highly prevalent in kidney and non-kidney pediatric transplant recipients. Standardized approaches to appropriate BP measurement and lipid monitoring are needed to detect and address these risk factors in a timely fashion. To achieve sustained improvement in cardiovascular health, clinicians should partner with patients and their caregivers to address these and other risk factors with a combined approach that integrates pharmacologic with non-pharmacologic approaches. This review outlines the scope and impact of hypertension and dyslipidemia in pediatric transplant recipients, with a particular focus on pediatric kidney transplantation given the high burden of chronic kidney disease-associated cardiovascular risk. We also review the current published guidelines for monitoring and managing abnormalities in blood pressure and lipids, highlighting the important role of therapeutic lifestyle changes in concert with antihypertensive and lipid-lowering medications.

The Improving Renal Outcomes Collaborative: Blood Pressure Measurement in Transplant Recipients

BACKGROUND AND OBJECTIVES

Hypertension is highly prevalent in pediatric kidney transplant recipients and contributes to cardiovascular death and graft loss. Improper blood pressure (BP) measurement limits the ability to control hypertension in this population. Here, we report multicenter efforts from the Improving Renal Outcomes Collaborative (IROC) to standardize and improve appropriate BP measurement in transplant patients.

METHODS

Seventeen centers participated in structured quality improvement activities facilitated by IROC, including formal training in quality improvement methods. The primary outcome measure was the proportion of transplant clinic visits with appropriate BP measurement according to published guidelines. Prospective data were analyzed over a 12-week pre-intervention period and a 20-week active intervention period for each center and then aggregated as of the program-specific start date. We used control charts to quantify improvements across IROC centers. We applied thematic analysis to identify patterns and common themes of successful interventions.

RESULTS

We analyzed data from 5392 clinic visits. At baseline, BP was measured and documented appropriately at 11% of visits. Center-specific interventions for improving BP measurement included educating clinic staff, assigning specific team member roles, and creating BP tracking tools and alerts. Appropriate BP measurement improved throughout the 20-week active intervention period to 78% of visits.

CONCLUSIONS

We standardized appropriate BP measurement across 17 pediatric transplant centers using the infrastructure of the IROC learning health system and substantially improved the rate of appropriate measurement over 20 weeks. Accurate BP assessment will allow further interventions to reduce complications of hypertension in pediatric kidney transplant recipients.

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

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

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).

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.

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.

Visfatin versus Flow-Mediated Dilatation as a Marker of Endothelial Dysfunction in Pediatric Renal Transplant Recipients

BACKGROUND

Renal transplantation (RTx) is the treatment of choice for paediatric end-stage renal disease (ESRD). A major cause of morbidity and mortality after RTx is cardiovascular disease. Independent predictors of cardiovascular events were shown to constitute an endothelial dysfunction (ED). This study aims to evaluate Visfatin serum level in comparison to brachial artery flow-mediated dilatation (FMD) as a marker of endothelial dysfunction in paediatric RTx recipients.

METHODS

Visfatin serum level has been evaluated in 30 patients on regular hemodialysis (HD), 36 patients post-RTx and 30 controls as a measure for ED, and has been compared to brachial artery FMD.

RESULTS

Visfatin level in transplant recipients was significantly lower than the hemodialysis group as well as FMD was better in transplant recipients. In spite of marked improvement of FMD and marked reduction of visfatin in post-RTx no direct statistical correlation was found between serum Visfatin level and flow-mediated dilatation.

CONCLUSION

Pediatric RTx recipients show lower serum Visfatin level and better FMD than those on regular hemodialysis, reflecting less endothelial dysfunction (ED) and less cardiovascular risk. FMD in kidney transplant recipients tends to be less than normal subjects while visfatin level of the same group is similar to controls. Pediatric RTx appears to have a positive impact on the growth development of children with ESRD.

A systems-based approach to managing blood pressure in children following kidney transplantation

Hypertension is one of the most common and well-known complications following kidney transplantation in children. Yet, despite numerous available therapies many pediatric kidney transplant recipients continue to have poorly controlled blood pressure, suggesting that traditional approaches to blood pressure management in this population might be inadequate. Over the last two decades, the Chronic Care Model has been developed to improve chronic illness outcomes through delivery system design and clinical information systems that support patient self-management and provider decision-making. In this educational review we discuss key elements of managing blood pressure following pediatric kidney transplantation and suggest ways that they may be reliably implemented into clinical practice using principles from the Chronic Care Model.

Long-Term Changes in Blood Pressure After Pediatric Kidney Transplantation

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Pretransplant Stable Systolic Cardiac Functions Play an Important Role in Short-term Systolic Cardiac Functions After Kidney Transplant in Children

OBJECTIVES

In this study, our aim was to evaluate the systolic cardiac parameters and related risk factors in children within 6 months after kidney transplant.

MATERIALS AND METHODS

We retrospectively evaluated 24 children who received kidney transplants. Clinical and laboratory parameters before and after transplant were recorded. Results were evaluated statistically, with a P value less than .05 considered significant.

RESULTS

Before transplant, systolic cardiac functions were within normal limits. After transplant, ejection fraction (63.35% ± 5.38% vs 66.95% ± 4.62%; P = .01) was significantly increased and left ventricular mass index (32.63 ± 17.21 g/m2.7 vs 31.29 ± 15.65 g/m2.7; P = .78) was not significantly decreased, whereas fractional shortening (52.16% ± 15.32% vs 59.8% ± 12.94%; P = .54) did not change. Systolic blood pressure, systolic blood pressure index, diastolic blood pressure, and diastolic blood pressure index values were not statistically different before and after transplant (P > .05). The number of antihypertensive agents was significantly decreased (P = .001). Before and after transplant, cardiac geometry was normal in 15 patients (62.5%) and 17 patients (70.8%).

CONCLUSIONS

Our patients, who had stable systolic cardiac function before transplant, showed further improvements in systolic cardiac function even within 6 months after transplant. Therefore, strictly monitored and controlled blood pressure, volume, anemia, and nutrition in children before transplant may play important roles in achieving better cardiac systolic function after kidney transplant.

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.

Treatment of hypertension in children with chronic kidney disease

Hypertension (HTN) is increasingly recognized as a common feature of pediatric chronic kidney disease (CKD). A growing body of evidence demonstrates that HTN is both underdiagnosed and undertreated in this population. The consequences of untreated HTN include adverse effects on CKD progression, markers of cardiovascular morbidity, and neurocognitive functioning. Consensus guidelines issued over the past decade have incorporated recent research on the consequences of HTN in recommendations for the diagnosis and treatment of HTN in pediatric CKD and include lower BP targets. Agents which target the renin-angiotensin-aldosterone system (RAAS) should be considered first-line therapy in CKD-associated HTN in children, though multiple medications may be required to achieve sufficient BP control.

Assessment and management of hypertension in transplant patients

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

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.

Transplant renal artery stenosis in children: risk factors and outcome after endovascular treatment

BACKGROUND

Transplant renal artery stenosis (TRAS) is an increasingly recognised cause of post-transplant hypertension.

METHODS

We retrospectively analysed 216 paediatric renal recipients transplanted between 2001 and 2011 to assess TRAS prevalence and percutaneous transluminal angioplasty (PTA) efficacy. To assess risk factors, we compared children with TRAS with a propensity score-matched cohort of recipients without TRAS.

RESULTS

Of the 216 paediatric patients who were transplanted in the study period, 44 were hypertensive (prevalence 20.3 %) and ten presented with TRAS (prevalence 4.6 %, median age at transplantation 14 years, range 6.78-17.36 years). Hypertensive patients without TRAS were prescribed one to two anti-hypertensive agents, whereas patients with TRAS required one to five medications. In the TRAS group, one recipient presented with vascular complications during surgery, and in three patients the graft had vascular abnormalities. TRAS was detected by Doppler ultrasonography (US) performed due to hypertension in nine of the patients with TRAS, but in the tenth case the TRAS was clinically silent and detected by routine Doppler-US screening. TRAS diagnosis was refined using angio-computed tomography or angio-magnetic resonance imaging. All patients underwent PTA without complications. Significant improvement after PTA was observed in the standard deviation scores for blood pressure [3.2 ± 1.4 (pre-PTA) vs. 1.04 ± 0.8 (post-PTA); p = 0.0006) and graft function [creatinine clearance: 69 ± 17.08 (pre-PTA) vs. 80.7 ± 21.5 ml/min/1.73 m(2) (post-PTA); p = 0.006] We observed no significant differences between the two cohorts for cold ischaemia time, recipient/donor weight ratio, delayed graft function, cytomegalovirus infections and acute rejection episodes.

CONCLUSIONS

Our study reports a low but significant TRAS prevalence among the paediatric patients who were transplanted at our centre in the study period and confirms that PTA is an effective and safe therapeutic option in paediatric renal transplant recipients. Known risk factors do not appear to be related to the development of TRAS.

Incidence and risk factors for early-onset hypertension after allogeneic hematopoietic stem cell transplantation in children

Background and Objectives

Survivors of pediatric hematopoietic stem cell transplantation (HSCT) are at risk for developing hypertension. The objectives of this study are to evaluate the prevalence and risk factors of early onset hypertension during the engraftment period after HSCT.

Subjects and Methods

This is a retrospective study of 157 consecutive patients (mean age at HSCT: 9.1±5.1 years) who underwent HSCT for acute myeloid leukemia (n=47), acute lymphoblastic leukemia (n=43), severe aplastic anemia (n=41), and other reasons (n=26). Blood pressure data were collected at five time points: 0, 7, 14, 21, and 28 days after HSCT. Hypertension was defined as having systolic and/or diastolic blood pressure ≥95th percentile according to age, gender, and height. To analyze the risk factors related to hypertension, data, including patients' demographic and transplant characteristics, were reviewed.

Results

Hypertension developed in 59 patients (38%), among whom 12 (7.6%) required long term therapy. Thirty-two (54%) patients had systolic and diastolic, 8 (14%) had only systolic, and 19 (32%) had only diastolic hypertension. Younger age, acute graft-versus-host disease, sinusoidal obstruction syndrome, treatment with antifungal agent, and greater increase in serum creatinine (Cr) levels were associated with hypertension. Multivariate analysis showed that younger age at HSCT and greater increase in serum Cr level were independent risk factors for hypertension.

Conclusion

Prevalence of hypertension during immediate post-HSCT period is high, especially in younger children. A greater increase in Cr after HSCT was significantly associated with hypertension. Further study is needed to elucidate long-term cardiovascular complications in pediatric HSCT survivors.

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.