Hypertension impairs vascular reactivity in the pediatric brain

Arterial Health Markers in Relation to Behavior and Cognitive Outcomes at School Age

BACKGROUND

Impaired arterial health is associated with a decline in cognitive function and psychopathology in adults. We hypothesized that these associations originate in early life. We examined the associations of blood pressure, common carotid artery intima media thickness, and carotid distensibility with behavior and cognitive outcomes during adolescence.

METHODS AND RESULTS

This study was embedded in the Dutch Generation R Study, a population-based prospective cohort study from early fetal life onwards. Blood pressure, carotid intima media thickness, and carotid distensibility were measured at the age of 10 years. At the age of 13 years, total, internalizing and externalizing problems and attention-deficit hyperactivity disorder symptoms were measured using the parent-reported Child Behavior Checklist (CBCL/6-18), autistic traits were assessed by the Social Responsiveness Scale, and IQ was assessed using the Wechsler Intelligence Scale for Children-Fifth Edition. A 1-SD score higher mean arterial pressure was associated with lower odds of internalizing problems (odds ratio [OR], 0.92 [95% CI, 0.85-0.99]). However, this association was nonsignificant after correction for multiple testing. Carotid intima media thickness and carotid distensibility were not associated with behavior and cognitive outcomes at 13 years old.

CONCLUSIONS

From our results, we cannot conclude that the associations of blood pressure, carotid intima media thickness, and carotid distensibility at age 10 years with behavior and cognitive outcomes are present in early adolescence. Further follow-up studies are needed to identify the critical ages for arterial health in relation to behavior and cognitive outcomes at older ages.

Associations of Arterial Thickness, Stiffness, and Blood Pressure With Brain Morphology in Early Adolescence: A Prospective Population-Based Study

BACKGROUND

Arterial wall thickness and stiffness, and high blood pressure have been repeatedly associated with poorer brain health. However, previous studies largely focused on mid- or late-life stages. It is unknown whether any arterial health-related brain changes may be observable already in adolescence.

METHODS

We examined whether (1) carotid intima-media thickness, (2) carotid distensibility, and (3) systolic blood pressure and diastolic blood pressure, measured at the age of 10 years, were associated with brain volumes and white matter microstructure (ie, fractional anisotropy and mean diffusivity) at the age of 14 years. In addition to cross-sectional analyses, we explored associations with longitudinal change in each brain outcome from 10 to 14 years. Analyses were based on 5341 children from the Generation R Study.

RESULTS

Higher diastolic blood pressure was associated with lower total brain volume (β, -0.04 [95% CI, -0.07 to -0.01]) and gray matter volume (β, -0.04 [95% CI, -0.07 to -0.01]) at the age of 14 years, with stronger associations in higher diastolic blood pressure ranges. Similar associations emerged between systolic blood pressure and brain volumes, but these were no longer significant after adjusting for birth weight. No associations were observed between blood pressure and white matter microstructure or between carotid intima-media thickness or distensibility and brain morphology.

CONCLUSIONS

Arterial blood pressure, but not intima-media thickness and distensibility, is associated with structural neuroimaging markers in early adolescence. Volumetric measures may be more sensitive to these early arterial health differences compared with microstructural properties of the white matter, but further studies are needed to confirm these results and assess potential causal mechanisms.

Effect of surgical intervention for childhood OSA on blood pressure: A randomized controlled study

OBJECTIVE

To investigate the effect of surgical intervention on 24-h ABP in children with OSA. It was hypothesized that blood pressure would improve following adenotonsillectomy.

METHODS

This was a two-centered investigator-blinded randomized controlled trial. Non-obese pre-pubertal children aged 6-11 years with OSA (obstructive apnea-hypopnea index, OAHI >3/h) underwent 24-h ABP monitoring at baseline and 9 months after the randomly assigned intervention, i.e. Early Surgery (ES) or Watchful Waiting (WW). Intention-to-treat analysis was performed.

RESULTS

137 subjects were randomized. Sixty-two (Age: 7.9y ± 1.3, 71% boys) and 47 (Age: 8.5y ± 1.6, 77% boys) participants from the ES and WW groups, respectively completed the study. Changes in ABP parameters were similar in the ES and WW groups (nighttime systolic BP z-scores: +0.03 ± 0.93 vs. -0.06 ± 1.04, p = 0.65; nighttime diastolic BP z-scores: -0.20 ± 0.95 vs. -0.02 ± 1.00, p = 0.35) despite a greater improvement in OSA in the ES group. However, a reduction in nighttime diastolic BP z-score correlated with improvements in OSA severity indexes (r = 0.21-0.22, p < 0.05), and a significant improvement in nighttime diastolic BP z-score [-0.43 ± 1.01, p = 0.027] following surgery was observed in participants with severe preoperative OSA (OAHI ≥10/h). The ES group had a significant increase in body mass index z-score after surgery [+0.27 ± 0.57, p < 0.001], which correlated with the increase in daytime systolic BP z-score (r = 0.2, p < 0.05).

CONCLUSION

Surgical treatment did not lead to significant improvements in ABP in OSA children except in those with more severe disease. The improvement in BP was partially masked by the weight gain following surgery.

CLINICAL TRIAL REGISTRATION

The trial was registered with the Chinese Clinical Trial Registry (http://www.chictr.org.cn.

REGISTRATION NUMBER

ChiCTR-TRC-14004131).

Impaired Neurovascular Function Underlies Poor Neurocognitive Outcomes and Is Associated with Nitric Oxide Bioavailability in Congenital Heart Disease

We use a non-invasive MRI proxy of neurovascular function (pnvf) to assess the ability of the vasculature to supply baseline metabolic demand, to compare pediatric and young adult congenital heart disease (CHD) patients to normal referents and relate the proxy to neurocognitive outcomes and nitric oxide bioavailability. In a prospective single-center study, resting-state blood-oxygen-level-dependent (BOLD) and arterial spin labeling (ASL) MRI scans were successfully obtained from 24 CHD patients (age = 15.4 ± 4.06 years) and 63 normal referents (age = 14.1 ± 3.49) years. Pnvf was computed on a voxelwise basis as the negative of the ratio of functional connectivity strength (FCS) estimated from the resting-state BOLD acquisition to regional cerebral blood flow (rCBF) as estimated from the ASL acquisition. Pnvf was used to predict end-tidal CO2 (P_ETCO2) levels and compared to those estimated from the BOLD data. Nitric oxide availability was obtained via nasal measurements (nNO). Pnvf was compared on a voxelwise basis between CHD patients and normal referents and correlated with nitric oxide availability and neurocognitive outcomes as assessed via the NIH Toolbox. Pnvf was shown as highly predictive of P_ETCO2 using theoretical modeling. Pnvf was found to be significantly reduced in CHD patients in default mode network (DMN, comprising the ventromedial prefrontal cortex and posterior cingulate/precuneus), salience network (SN, comprising the insula and dorsal anterior cingulate), and central executive network (CEN, comprising posterior parietal and dorsolateral prefrontal cortex) regions with similar findings noted in single cardiac ventricle patients. Positive correlations of Pnvf in these brain regions, as well as the hippocampus, were found with neurocognitive outcomes. Similarly, positive correlations between Pnvf and nitric oxide availability were found in frontal DMN and CEN regions, with particularly strong correlations in subcortical regions (putamen). Reduced Pnvf in CHD patients was found to be mediated by nNO. Mediation analyses further supported that reduced Pnvf in these regions underlies worse neurocognitive outcome in CHD patients and is associated with nitric oxide bioavailability. Impaired neuro-vascular function, which may be non-invasively estimated via combined arterial-spin label and BOLD MR imaging, is a nitric oxide bioavailability dependent factor implicated in adverse neurocognitive outcomes in pediatric and young adult CHD.

Hypertension and cognitive function: a review of life-course factors and disparities

PURPOSE OF REVIEW

Dementia is a life-course condition with modifiable risk factors many from cardiovascular (CV) origin, and disproportionally affects some race/ethnic groups and underserved communities in the USA. Hypertension (HTN) is the most common preventable and treatable condition that increases the risk for dementia and exacerbates dementia pathology. Epidemiological studies beginning in midlife provide strong evidence for this association. This study provides an overview of the differences in the associations across the lifespan, and the role of social determinants of health (SDoH).

RECENT FINDINGS

Clinical trials support HTN management in midlife as an avenue to lower the risk for late-life cognitive decline. However, the association between HTN and cognition differs over the life course. SDoH including higher education modify the association between HTN and cognition which may differ by race and ethnicity. The role of blood pressure (BP) variability, interactions among CV risk factors, and cognitive assessment modalities may provide information to better understand the relationship between HTN and cognition.

SUMMARY

Adopting a life-course approach that considers SDoH, may help develop tailored interventions to manage HTN and prevent dementia syndromes. Where clinical trials to assess BP management from childhood to late-life are not feasible, observational studies remain the best available evidence.

The link between executive function, socio-emotional functioning and health-related quality of life in children and adolescents with mild to moderate chronic kidney disease

BACKGROUND

Children and adolescents with mild to moderate chronic kidney disease (CKD) are at high risk for mild but persistent impairment in executive functions, which have been associated with low health-related quality of life (HRQOL) among children and adolescents with chronic health conditions. However, no similar link has been established among children and adolescents with mild to moderate CKD. Given the essential role executive functions play in the development of adequate cognitive, emotional and social skills, it is essential to gain a clearer understating of the magnitude and attributes of executive functions and its link to HRQOL in order to inform appropriate medical and educational interventions for this patient population.

OBJECTIVE

The aim of this study is to examine the relationship between executive functions, socio-emotional functioning and HRQOL in children and adolescents with mild to moderate CKD.

METHODS

A cross-sectional design was used for this secondary data analysis of 199 children and adolescents (ages 6-17) with mild to moderate CKD from the United States and Canada who receive care at hospitals associated with the Chronic Kidney Disease in Children Study (CKiD).

RESULTS

The presence of impairment in executive functions and socio-emotional functioning (internalizing problems) significantly predicted lower HRQOL after controlling for key covariates (i.e., maternal education, anaemia and hypertension). Further, internalizing problems partially mediated the relationship between executive functions and HRQOL such that impairment in executive functions predicted lower HRQOL directly and indirectly by contributing to higher internalizing problems, which further contributed to low HRQOL.

CONCLUSION

This study underscores the importance of executive functions and socio-emotional functioning in the manifestation of HRQOL. Given that HRQOL is potentially compromised for many children and adolescents with mild to moderate CKD, it will be important for both clinicians and researchers to examine a range of factors, including executive functions and socio-emotional functioning, in order to optimize HRQOL.

The pressure's on: understanding neurocognitive and psychological associations with pediatric hypertension to inform comprehensive care

The prevalence of hypertension is increasing in pediatric populations. While clinical data and practice guidelines identify the impact of hypertension on organ dysfunction and emphasize the importance for end-organ damage screening, the bidirectional effects of pediatric hypertension on neurocognitive and psychological outcomes are understudied. The objective of this review is to highlight the association between hypertension and cognition, attention, learning, and mental health in children and adolescents. In doing so, this review provides a framework and toolkit to integrate neuropsychology and psychology into the screening and management stages of pediatric hypertension. By recognizing the effects of hypertension on cognition, behavior, and mental health, screenings and interventions can be implemented to proactively and comprehensively improve the health outcomes for children with blood pressure concerns.

Hypertension and childhood stroke

Cerebrovascular disease (stroke) is one of the ten leading causes of death in children and adolescents. Multiple etiologies, from arteriopathies to prothrombic states, can cause stroke in youth. In adult stroke, hypertension has been shown to be the single most important modifiable risk factor. Although hypertension has not been strongly identified as a risk factor in childhood stroke to date, there is preliminary evidence that suggests that hypertension may also be associated with stroke in children. In this review, we summarize the literature that may link hypertension to stroke in the young. We have identified a series of barriers and limitations in the fields of pediatric hypertension and pediatric neurology that might explain why hypertension has been overlooked in childhood stroke. We suggest that hypertension may be a relevant risk factor that, alone or in combination with other multiple factors, contributes to the development of stroke in children. Currently, there are no consensus guidelines for the management of post-stroke hypertension in children. Thus, we recommend that blood pressure be assessed carefully in every child presenting with acute stroke in order to better understand the effects of hypertension in the development and the outcome of childhood stroke. We suggest a treatment algorithm to help practitioners manage hypertension after a stroke.

Exosomal MicroRNAs Contribute to Cognitive Impairment in Hypertensive Patients by Decreasing Frontal Cerebrovascular Reactivity

Mechanisms underlying cognitive impairment (CI) in hypertensive patients remain relatively unclear. The present study aimed to explore the relationship among serum exosomal microRNAs (miRNAs), cerebrovascular reactivity (CVR), and cognitive function in hypertensive patients. Seventy-three hypertensive patients with CI (HT-CI), 67 hypertensive patients with normal cognition (HT-NC), and 37 healthy controls underwent identification of exosomal miRNA, multimodal magnetic resonance imaging (MRI) scans, and neuropsychological tests. CVR mapping was investigated based on resting-state functional MRI data. Compared with healthy subjects and HT-NC subjects, HT-CI subjects displayed decreased serum exosomal miRNA-330-3p. The group difference of CVR was mainly found in the left frontal lobe and demonstrated that HT-CI group had a lower CVR than both HT-NC group and control group. Furthermore, both the CVR in the left medial superior frontal gyrus and the miRNA-330-3p level were significantly correlated with executive function (r = -0.275, P = 0.021, and r = -0.246, P = 0.04, respectively) in HT-CI subjects, and the CVR was significantly correlated with the miRNA-330-3p level (r = 0.246, P = 0.040). Notably, path analysis showed that the CVR mediated the association between miRNA-330-3p and executive function. In conclusion, decreased miRNA-330-3p might contribute to CI in hypertensive patients by decreasing frontal CVR and could be a biomarker of early diagnosis.

Magnetic Resonance Imaging in Childhood Primary Hypertension: Potential in the Study of Cognitive Outcomes

Primary hypertension in youth and young adulthood is associated with decreased neurocognitive test performance both in midlife and during youth itself, leading to concern of subsequent cognitive decline and dementia in later life. The early vascular effects of hypertension in youth are likely involved in the pathogenesis of hypertensive target organ damage to the brain, but the potential impact of antihypertensive treatment from youth on subsequent cognitive health is not known. This review will highlight the need to answer the question of whether treatment of hypertension from early in life would slow cognitive decline in adulthood, and will then outline, for the nonneurologist, magnetic resonance imaging techniques potentially useful in the study of the pathogenesis of decreased cognition in hypertensive youth and for use as potential biomarkers for early antihypertensive treatment interventions.

Mild hypertension protects the elderly from cognitive impairment: a 7-year retrospective cohort study

AIM

People with mild cognitive impairment have a high risk of converting to dementia. Previous studies have suggested that hypertension is implicated in the development of mild cognitive impairment, but such effect in people much older than 70 years may be quite different. The aim of the study was to reveal the relationship between hypertension and mild cognitive impairment risk in this age group.

METHODS

A total of 985 subjects were retrospectively enrolled from Tianjin Medical University General Hospital, and all of them were cognitively normal 7 years earlier. During these years, 134 subjects were diagnosed with mild cognitive impairment according to the Mini-Mental State Examination. Research data of all the subjects were collected from medical records.

RESULTS

Multivariate Cox regression analysis revealed that compared with the subjects without hypertension, the subjects with grade 1 hypertension or duration <10 years showed a decreased risk of mild cognitive impairment (hazards ratio (HR): 0.54, 95%CI: 0.32-0.87; HR: 0.65, 95%CI: 0.40-0.99), and the subjects with grade 2-3 hypertension or duration ≥10 years had an increased risk of the disease (HR: 1.75, 95%CI: 1.25-2.42; HR: 1.52, 95%CI: 1.08-2.15). In addition, compared with the patients without hypertension, the patients taking angiotensin II receptor antagonists / angiotensin converting enzyme inhibitors had an increased risk of the disease (HR: 1.91, 95%CI: 1.29-2.83).

CONCLUSION

In subjects over 70 years old, short-term and mild hypertension might be a protective factor for mild cognitive impairment and prevent them from such a disease.

Cardiorespiratory fitness, blood pressure, and cerebral oxygenation during a dual-task in healthy young males

This study aimed to evaluate the effects of cardiorespiratory fitness (CRF) and mean arterial pressure (MAP) on the prefrontal cortex (PFC) oxygenation and dual-task performance in healthy young males. Changes in the concentration of oxygenated (ΔHbO₂) and deoxygenated hemoglobin (ΔHHb) in the right and left PFC were examined during a cognitive auditory 2-back task. Cognitive performance (2-back task's accuracy) and walking motor performances were measured in single-tasks (single motor and single cognitive) and dual-task (2-back task + walking). Thirty-six young males were ranked according to their V˙O₂peak. The second tertile was excluded to generate two groups of different CRF (high fit group: n = 12 and V˙O₂peak = 56.0 ± 6.7 ml kg^-1 min^-1; low-fit group: n = 12 and V˙O₂peak = 36.7 ± 4.1 ml kg^-1 min^-1). The CRF groups were further split into two subgroups according to 24-h MAP (higher-MAP, lower-MAP). Two-way ANOVA (CRF x n-back conditions) revealed a significant interaction between the CRF and cognitive task condition on 2-back accuracy (p =  .007) and a main effect of CRF on ⊗HHb in the right and left PFC (p < .05). These results suggest that in healthy young males: 1) for CRF, only low-fit individuals demonstrate dual-task costs in accuracy (Dual < Single), and 2) that in comparison to the low-fit group, the high fit-group demonstrated greater changes in PFC oxygenation in ΔHHb, but not ΔHbO₂.

Association of Blood Pressure and Arterial Stiffness With Cognition in 2 Population-Based Child and Adult Cohorts

Background High blood pressure levels and higher arterial stiffness have been shown to be associated with lower cognition during adulthood, possibly by accumulative changes over time. However, vascular factors may already affect the brain during early life. Methods and Results We examined the relation between cognition and vascular factors within 5853 children from the Generation R Study (mean age 6.2 years) and 5187 adults from the Rotterdam Study (mean age 61.8 years). Diastolic and systolic blood pressure and arterial stiffness were assessed, the latter by measuring pulse-wave velocity and pulse pressure. For cognition, the Generation R Study relied on nonverbal intelligence, whereas the Rotterdam Study relied on a cognitive test battery to calculate the g-factor, a measure of global cognition. In the Generation R Study, standardized diastolic blood pressure showed a significant association with standardized nonverbal intelligence (β=-0.030, 95% confidence interval=[-0.054; -0.005]) after full adjustment. This association held up after excluding the top diastolic blood pressure decile (β=-0.042 [-0.075; -0.009]), suggesting that the relation holds in normotensives. Within the Rotterdam Study, standardized cognition associated linearly with standardized systolic blood pressure (β=-0.036 [-0.060; -0.012]), standardized pulse-wave velocity (β=-0.064 [-0.095; -0.033]), and standardized pulse pressure (β=-0.044 [-0.069; -0.020], and nonlinearly with standardized diastolic blood pressure (quadratic term β=-0.032 [-0.049; -0.015]) after full adjustment. Conclusions Blood pressure and cognition may already be related in the general population during early childhood, albeit differently than during adulthood.

Magnetic resonance imaging of cerebrovascular reactivity in healthy adolescents

BACKGROUND

Cerebrovascular reactivity (CVR), an important measure of cerebrovascular health in adults, has not been examined in healthy adolescents. Beyond the direct importance of understanding CVR in healthy youth, studies on this topic can yield insights regarding brain disease. We set out to evaluate 3 different CVR modelling approaches.

NEW METHOD

Thirty-nine healthy adolescents (ages 13-19 years, 20 females) completed six blocks of 15-second breath-holds separated by 30-second blocks of free-breathing. CVR was measured using blood-oxygenation-level dependent functional magnetic resonance imaging at 3-Tesla; voxel-wise analyses were complemented by regional analyses in five major subdivisions of the brain. Hemodynamic response functions were modelled using: (1) an individualized delay term (double-gamma variate convolved with a boxcar function), (2) with a standard 9-second delay term, and (3) a sine-cosine regressor.

RESULTS

Individual-delay yielded superior model fit or larger cluster volumes. Regional analysis found differences in CVR and time-to-peak CVR. Males had higher brain-wide CVR in comparison to females (p = 0.025, η²_part = 0.345). BMI and blood pressure were not significantly associated with CVR (all p > 0.4).

COMPARISON WITH EXISTING METHODS

This was the first study to compare these methods in youth. Regional differences were similar to adult studies.

CONCLUSIONS

These findings lend support to future breath-hold CVR studies in youth, and highlight the merit of applying individualized-delay estimates. Regional variability and sex-related differences in CVR suggest that these variables should be considered in future studies, particularly those that examine disease states with predilection for specific brain regions or those diseases characterized by sex differences.

Whole blood viscosity and cerebral blood flow velocities in obese hypertensive or obese normotensive adolescents

BACKGROUND

Obesity affects all major organ systems and leads to increased morbidity and mortality. Whole blood viscosity is an important independent regulator of cerebral blood flow. The aim of the present study was to evaluate the effect of whole blood viscosity on cerebral artery blood flow velocities using transcranial Doppler ultrasound in pediatric patients with obesity compared to healthy controls and analyze the effect of whole blood viscosity and blood pressure status to the cerebral artery blood flow velocities.

METHODS

Sixty patients with obesity diagnosed according to their body mass index (BMI) percentiles aged 13-18 years old were prospectively enrolled. They were grouped as hypertensive or normotensive according to their ambulatory blood pressure monitoring. Whole blood viscosity and middle cerebral artery velocities by transcranial Doppler ultrasound were studied and compared to 20 healthy same aged controls.

RESULTS

Whole blood viscosity values in hypertensive (0.0619±0.0077 poise) and normotensive (0.0607±0.0071 poise) groups were higher than controls (0.0616±0.0064 poise), with no significance. Middle cerebral artery blood flow velocities were higher in the obese hypertensive (73.9±15.0 cm/s) and obese normotensive groups (75.2±13.5 cm/s) than controls (66.4±11.5 cm/s), but with no statistical significance.

CONCLUSIONS

Physiological changes in blood viscosity and changes in blood pressure did not seem to have any direct effect on cerebral blood flow velocities, the reason might be that the cerebral circulation is capable of adaptively modulating itself to changes to maintain a uniform cerebral blood flow.

Clinical Practice Guideline for Screening and Management of High Blood Pressure in Children and Adolescents

These pediatric hypertension guidelines are an update to the 2004 "Fourth Report on the Diagnosis, Evaluation, and Treatment of High Blood Pressure in Children and Adolescents." Significant changes in these guidelines include (1) the replacement of the term "prehypertension" with the term "elevated blood pressure," (2) new normative pediatric blood pressure (BP) tables based on normal-weight children, (3) a simplified screening table for identifying BPs needing further evaluation, (4) a simplified BP classification in adolescents ≥13 years of age that aligns with the forthcoming American Heart Association and American College of Cardiology adult BP guidelines, (5) a more limited recommendation to perform screening BP measurements only at preventive care visits, (6) streamlined recommendations on the initial evaluation and management of abnormal BPs, (7) an expanded role for ambulatory BP monitoring in the diagnosis and management of pediatric hypertension, and (8) revised recommendations on when to perform echocardiography in the evaluation of newly diagnosed hypertensive pediatric patients (generally only before medication initiation), along with a revised definition of left ventricular hypertrophy. These guidelines include 30 Key Action Statements and 27 additional recommendations derived from a comprehensive review of almost 15 000 published articles between January 2004 and July 2016. Each Key Action Statement includes level of evidence, benefit-harm relationship, and strength of recommendation. This clinical practice guideline, endorsed by the American Heart Association, is intended to foster a patient- and family-centered approach to care, reduce unnecessary and costly medical interventions, improve patient diagnoses and outcomes, support implementation, and provide direction for future research.

Defining the Relationship Between Hypertension, Cognitive Decline, and Dementia: a Review

Hypertension is a highly prevalent condition which has been established as a risk factor for cardiovascular and cerebrovascular disease. Although the understanding of the relationship between cardiocirculatory dysfunction and brain health has improved significantly over the last several decades, it is still unclear whether hypertension constitutes a potentially treatable risk factor for cognitive decline and dementia. While it is clear that hypertension can affect brain structure and function, recent findings suggest that the associations between blood pressure and brain health are complex and, in many cases, dependent on factors such as age, hypertension chronicity, and antihypertensive medication use. Whereas large epidemiological studies have demonstrated a consistent association between high midlife BP and late-life cognitive decline and incident dementia, associations between late-life blood pressure and cognition have been less consistent. Recent evidence suggests that hypertension may promote alterations in brain structure and function through a process of cerebral vessel remodeling, which can lead to disruptions in cerebral autoregulation, reductions in cerebral perfusion, and limit the brain's ability to clear potentially harmful proteins such as β-amyloid. The purpose of the current review is to synthesize recent findings from epidemiological, neuroimaging, physiological, genetic, and translational research to provide an overview of what is currently known about the association between blood pressure and cognitive function across the lifespan. In doing so, the current review also discusses the results of recent randomized controlled trials of antihypertensive therapy to reduce cognitive decline, highlights several methodological limitations, and provides recommendations for future clinical trial design.

Stroke and Hypertension in Children and Adolescents

Hypertension is the single most important modifiable risk factor for adult stroke. Stroke mortality has significantly decreased over the last 5 decades; this decline has been mainly associated to improved blood pressure control. Though much less prevalent than in adults, stroke is an increasingly recognized cause of morbidity and mortality in children. Although hypertension has not been strongly identified as a risk factor in childhood stroke yet, there is preliminary evidence that suggests that elevated blood pressure may be associated with stroke in children. This review summarizes the literature that may link elevated blood pressure to the development of childhood ischemic and hemorrhagic stroke. The authors suggest that elevated blood pressure may be a significant risk factor that, alone or in combination with other multiple risk factors, leads to the development of stroke in childhood. It is therefore recommend that blood pressure be measured and assessed carefully in every child presenting with acute stroke.

Neurological Complications of Renal Disease

Neurological manifestations related to electrolyte disorders, drug toxicity, and uremia are common in chronic kidney disease (CKD). Seizures and coma are frequent complications of acute renal insufficiency (uremia), whereas peripheral neuropathy and encephalopathy, observed in progressive uremia, are terminal events. Failure to excrete metabolic products causes their accumulation and can lead to severe intoxication. Clinically, the signs and symptoms of uremia can vary widely, depending on the biological characteristics of the patient, the specific type of renal disease, and the time of the uremic intoxication. CKD is an increasing problem worldwide and is now being recognized as a global health burden particularly for cardiovascular and cerebrovascular ischemic events. Despite improvements in the medical management of advanced CKD, including dialysis and transplantation, patients manifest a number of symptoms that neurologists are often confronted with. Appropriate drug dosing, awareness of potential side effects of medications, prompt diagnosis, and treatment are essential in preventing neurological long-term morbidity and mortality.

Ambulatory Blood Pressure Monitoring in Frequently Relapsing Nephrotic Syndrome

OBJECTIVES

To screen patients with frequently relapsing nephrotic syndrome (FRNS) for the presence of ambulatory hypertension and left ventricular hypertrophy.

METHODS

Following ethical and parental approvals, consecutive patients with FRNS of ≥2 y duration were enrolled. Those with estimated glomerular filtration rate <60 ml/min/1.73 m² and known familial hypercholesterolemia or diabetes mellitus were excluded. Clinic blood pressure was measured by oscillometry and 24-h ambulatory blood pressure was recorded by Spacelab 90207; echocardiography was done for left ventricular mass. Ambulatory hypertension was defined as the presence of clinic blood pressure >95th centile for age, sex and height, and systolic blood pressure load exceeding 25 %.

RESULTS

Of 99 patients, 73 were boys; their median (IQR) age was 120 (84-156) mo. Clinic blood pressure was >95th percentile in 63 (63.6 %) patients. Ambulatory hypertension was present in 33 (33.3 %), including 14 patients with severe hypertension; 16 (16.1 %) had masked hypertension and 30 (30.3 %) had white coat hypertension. Non-dipping was seen in 72 and 55 patients had high nocturnal systolic blood pressure load. Of 21 patients with increased left ventricular mass index, 9 (42.9 %) had ambulatory hypertension, 3 (14.3 %) had masked hypertension and 6 (28.6 %) patients had white coat hypertension. Compared to those with normal blood pressure, patients with ambulatory hypertension were younger at onset of nephrotic syndrome (odds ratio, OR 0.94; 95 % CI 0.91-0.98; P = 0.002), longer duration of frequently relapsing disease (OR 1.05; 95 % CI 1.00-1.10; P = 0.034) and higher body mass index (BMI) (OR 1.61; 95 % CI 1.07-4.40; P = 0.020). BMI was positively correlated with 24-h systolic blood pressure load (r = 0.23; P = 0.002) and with the left ventricular mass index (r = 0. 57; P = 0.001).

CONCLUSIONS

Many patients with FRNS showed high prevalence of clinic, ambulatory and white coat hypertension, emphasizing the need to carefully screen these patients in order to ensure their appropriate management. While clinic blood pressure monitoring detects most patients with hypertension, it misses a significant proportion with masked hypertension, underscoring the need for ambulatory blood pressure monitoring and screening for end organ damage. High BMI was the chief risk factor for hypertension, suggesting that control of overweight and hypertension might improve cardiovascular outcomes.

Young Patients With Diabetes Have Decreased Cerebrovascular Reactivity Under Hypercapneic Conditions

OBJECTIVE

Adult diabetic patients have an abnormal cerebrovascular response to hypercapnia, but there are few studies focused on diabetes mellitus type 1 and cerebral blood flow in pediatric or adolescent patients. We hypothesize that young patients with diabetes exhibit a different response to hypercapnia than normal control counterparts.

METHODS

Using transcranial Doppler techniques, we compared young diabetic patients with healthy controls by measuring cerebral blood velocity before and during carbon dioxide challenge.

RESULTS

Subjects with diabetes had decreased cerebral blood velocity reactivity when compared with the control group (P = 0.005).

CONCLUSION

Our results suggest cerebrovascular dysfunction in diabetic patients beginning at an early age. The possibility of long-term implications for cerebrovascular disease demonstrates the need for further studies in the pediatric and adolescent diabetic population to better understand this prevalent condition.

Neurocognitive Dysfunction in Children, Adolescents, and Young Adults With CKD

BACKGROUND

Neurocognitive dysfunction is a known complication in children with chronic kidney disease (CKD). However, less is known about putative mechanisms or modifiable risk factors. The objective of this study was to characterize and determine risk factors for cognitive dysfunction in children, adolescents, and young adults with CKD compared with controls.

STUDY DESIGN

Cross-sectional study.

SETTING & PARTICIPANTS

The Neurocognitive Assessment and Magnetic Resonance Imaging Analysis of Children and Young Adults With Chronic Kidney Disease (NiCK) Study included 90 individuals aged 8 to 25 years with CKD compared with 70 controls.

PREDICTORS

CKD versus control, estimated glomerular filtration rate (eGFR), ambulatory blood pressure.

OUTCOMES

Performance on neurocognitive assessment with relevant tests grouped into 11 domains defined a priori by expert opinion. Results of tests were converted to age-normalized z scores.

MEASUREMENTS

Each neurocognitive domain was analyzed through linear regression, adjusting for eGFR and demographic and clinical variables. For domains defined by multiple tests, the median z score of tests in that domain was used.

RESULTS

We found significantly poorer performance in multiple areas of neurocognitive function among individuals with CKD compared with controls. Particular deficits were seen in domains related to attention, memory, and inhibitory control. Adjusted for demographic and clinical factors, we found lower performance in multiple domains with decreasing eGFRs (attention: β=0.053, P=0.02; visual spatial: β=0.062, P=0.02; and visual working memory: β=0.069, P=0.04). Increased diastolic load and decreased diastolic nocturnal dipping on ambulatory blood pressure monitoring were independently associated with impairments in neurocognitive performance.

LIMITATIONS

Unable to assess changes in neurocognitive function over time, and neurocognitive tests were grouped into predetermined neurocognitive domains.

CONCLUSIONS

Lower eGFR in children, adolescents, and young adults is associated with poorer neurocognitive performance, particularly in areas of attention, memory, and inhibitory control. Hypertension identified on ambulatory blood pressure monitoring may be an important risk factor, illustrating that neurocognitive function is an area of target-organ damage in CKD.

Nocturnal Blood Pressure in Young Adults and Cognitive Function in Midlife: The Coronary Artery Risk Development in Young Adults (CARDIA) Study

BACKGROUND

Nocturnal blood pressure (BP) is associated with risk for cardiovascular events. However, the relationship between nocturnal BP in young adults and cognitive function in midlife remains unclear.

METHODS

We used data from the ambulatory BP monitoring substudy of the Coronary Artery Risk Development in Young Adults Study, including 224 participants (mean age 30 years, 45% men, 63% African Americans). At the 20-year follow-up, the Stroop test (executive function), Digit Symbol Substitution Test (psychomotor speed), and Rey Auditory Verbal Learning Test (verbal memory) were assessed.

RESULTS

Baseline mean office, daytime, and nocturnal BP were 109/73, 120/74, and 107/59 mm Hg, respectively. Nocturnal BP dipping, calculated as (nocturnal systolic BP [SBP]--daytime SBP) × 100/daytime SBP, was divided into quartiles (Q1: -39.3% to -16.9%; Q2: -16.8% to -13.2%, Q3 [reference]: -13.1% to -7.8%, and Q4: -7.7% to +56.4%). In multiple regression analyses, the least nocturnal SBP dipping (Q4 vs. reference) and higher nocturnal diastolic BP level were associated with worse Stroop scores, with adjustments for demographic and clinical characteristics, and cumulative exposure to office BP during follow-up (β [standard error]: 0.37 [0.18] and 0.19 [0.07], respectively; all P < 0.05). Digit Symbol Substitution Test and Rey Auditory Verbal Learning Test were not significantly associated with nocturnal SBP dipping or nocturnal SBP/diastolic BP levels.

CONCLUSIONS

Among healthy young adults, less nocturnal SBP dipping and higher nocturnal diastolic BP levels were associated with lower executive function in midlife, independent of multiple measures of office BP during long-term follow-up.

Executive function and cerebrovascular reactivity in pediatric hypertension

Primary hypertension is associated with decreased performance on neurocognitive testing and a blunted cerebrovascular reactivity to hypercapnia. Parents of 14 children with hypertension and prehypertension completed the Behavior Rating Inventory of Executive Functions. Children underwent 24-hour ambulatory blood pressure monitoring and transcranial Doppler with reactivity measurement using time-averaged maximum mean velocity and end-tidal carbon dioxide during hypercapnia-rebreathing test. Comparing the reactivity slope for the patients to historical controls showed a statistically significant difference (t = -5.19, df = 13, P < .001), with lower slopes. Pearson correlations of the Behavior Rating Inventory of Executive Functions scores with the reactivity slopes showed a statistically significant inverse relationship with Behavioral Regulation Index (r = -.60, P = .02), Metacognition Index (r = -.40, P = .05), and the Global Executive Component (r = -.53, P = .05). Children with hypertension have decreased executive function, and this correlates to low transcranial Doppler-reactivity slopes, suggesting that the brain is a target organ in hypertensive children.

Cognitive function in hypertensive children

Young hypertensive adults demonstrate decreased performance on neurocognitive testing compared with that of normotensive controls. There is emerging, preliminary evidence that children with hypertension also manifest cognitive differences when compared to normotensive controls. These preliminary studies consist mostly of database and single-center studies that focus primarily on differences in neurocognitive test performance and differences in cerebrovascular reactivity between hypertensive and normotensive subjects. Lessons from the literature on cognition in adult hypertensives and experience from the preliminary studies in children informed the design of a current, multicenter, ongoing study of cognition in children with primary hypertension.

Primary hypertension in childhood

There is growing concern about elevated blood pressure in children and adolescents, because of its association with the obesity epidemic. Moreover, cardiovascular function and blood pressure level are determined in childhood and track into adulthood. Primary hypertension in childhood is defined by persistent blood pressure values ≥ the 95th percentile and without a secondary cause. Preventable risk factors for elevated blood pressure in childhood are overweight, dietary habits, salt intake, sedentary lifestyle, poor sleep quality and passive smoking, whereas non-preventable risk factors include race, gender, genetic background, low birth weight, prematurity, and socioeconomic inequalities. Several different pathways are implicated in the development of primary hypertension, including obesity, insulin resistance, activation of the sympathetic nervous system, alterations in sodium homeostasis, renin-angiotensin system and altered vascular function. Prevention of adult cardiovascular disease should begin in childhood by regularly screening for high blood pressure, counseling for healthy lifestyle and avoiding preventable risk factors.

Primary hypertension and neurocognitive and executive functioning in school-age children

Data on neurocognitive function in hypertensive children are limited. In this review, we summarize recent preliminary, early studies that suggest that children with elevated blood pressure demonstrate evidence of worse performance on direct neurocognitive testing, as well as evidence of executive dysfunction based on parent ratings, compared with matched normotensive comparison groups. Furthermore, hypertensive children may have increased prevalence of learning disabilities as well as a blunted cerebrovascular reactivity compared with normotensive controls. Larger, prospective studies are needed to confirm and further explore these emerging but preliminary findings.

Impact of metabolic syndrome on cognition and brain: a selected review of the literature

Metabolic syndrome (MetS), a clustering of risk factors for type 2 diabetes mellitus and cardiovascular disease, has been associated with cognitive dysfunction and brain abnormalities. This review describes the literature on the impact of MetS on brain and cognition and suggests directions for future research. A literature search for reports of MetS and cognition and brain imaging was conducted for both nonelderly adults and adolescents. No studies were found describing MetS and brain or cognition among adolescents; therefore, we also included studies investigating individual components of MetS in this age group. Most studies found associations between MetS and cognitive dysfunction. Multiple cognitive domains were affected by MetS in adults. In adolescents, the majority of findings were in executive functioning. Brain imaging literature in adults implicated MetS in ischemic stroke, white matter alterations, and altered brain metabolism. For adolescents, individual MetS factors were linked to volume losses in the hippocampus and frontal lobes. MetS negatively impacts cognitive performance and brain structure. Potential explanatory models include impaired vascular reactivity, neuroinflammation, oxidative stress, and abnormal brain lipid metabolism. We posit that insulin resistance-associated impairment in cerebrovascular reactivity is an important mechanism underlying brain deficits seen in MetS.

Neurocognitive alterations in hypertensive children and adolescents

Hypertensive adults demonstrate performance deficits on neuropsychological testing compared with scores of normotensive controls. This article reviews emerging preliminary evidence that children with hypertension also manifest neurocognitive differences when compared with normotensive controls. Database and single-center studies suggest that children with hypertension manifest deficits on measures of neurocognition and have an increased prevalence of learning difficulties and that children with hypertension associated with obesity may be at increased risk for depression and anxiety. Studies suggesting blunted cerebrovascular reactivity in children with hypertension are also reviewed.

Brain hypoperfusion in a girl with systemic lupus erythematosus

We describe an adolescent girl with systemic lupus erythematosus, presenting with severe cardiovascular autonomic dysfunction and incapacitating orthostatic hypotension to a degree not previously reported. Further evaluation of cerebral blood flow velocity, using transcranial Doppler testing, demonstrated an abnormal hypercapnic cerebrovascular response. Both the orthostatic hypotension and the abnormal cerebrovascular hypercapnic response improved with intensive medical treatment of her systemic lupus erythematosus. Additional studies are necessary to elucidate the pathogenesis of these cerebrovascular and autonomic abnormalities, especially considering the potential consequences they may exert on cerebral perfusion, which may be subtle, underrecognized, and capable of affecting cognition.