By Shaimaa Sayed Agenda Introduction Definition Technique Values Problems Other methods for assessment of blood pressure Ambulatory blood pressure monitoring and abnormalities of vascular structure ID: 918851
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Slide1
Ambulatory blood pressure monitoring in children
By
Shaimaa
Sayed
Slide2Agenda
Introduction
Definition
Technique
Values
Problems
Other methods for assessment of blood pressure
Ambulatory blood pressure monitoring and abnormalities of vascular structure.
Slide3Introduction
The assessment of blood pressure is challenging in children, especially in very young individuals, due to their variable body size and lack of cooperation.
So, it needs to be measured repeatedly on regular clinic and extra-clinic visits, to establish if it is truly elevated.
Ambulatory blood pressure monitoring (ABPM) is an important tool in evaluating pediatric hypertension.
It is also more reliable than casual blood pressure by providing multiple readings over time.
Slide4Ambulatory blood pressure monitoring
Definition:
It is a non-invasive procedure in which a portable blood pressure device, worn by a patient, periodically records blood pressure over a specified period of time, usually 24 hours.
It measures the average systolic and diastolic blood pressure during both patient’s regular daily activities and sleep.
It typically yields 40–80 readings.
It measures the proportion of time that the systolic and diastolic blood pressure is abnormally high.
Slide5Ambulatory blood pressure monitoring
The percent of number of values that exceeding the upper limit of normal range, is known as blood pressure load.
Abnormalities of ambulatory blood pressure predict the development of hypertensive end-organ damage, specifically left ventricular hypertrophy.
Slide6Ambulatory blood pressure monitoring
Technique:
The patient has a blood pressure cuff with suitable size.
The patient wears the cuff and a small electronic device which can be worn in a pocket.
The device prompts the cuff to inflate every 20 minutes during the day and every 30 minutes at night to measure blood pressure and also records the readings.
The patient wears the monitor for 24 hours.
Slide7Ambulatory blood pressure monitoring
Technique:
Patients are advised to avoid heavy physical activity during the study.
The monitor is then returned to the clinic and the readings are downloaded for analysis.
The
nephrologist
reviews these results with the patient and family.
Slide8Slide9Ambulatory blood pressure monitoring
Values:
ABPM is the best way to differentiate true hypertension from white coat hypertension.
Up to 30% of children with elevated clinic blood pressure actually have white coat hypertension.
So, they may be spared from unnecessary therapy.
But, these children are at increased risk for true hypertension and cardiovascular disease, so annual ABPM may be necessary.
Slide10Ambulatory blood pressure monitoring
Values:
Masked hypertension is the phenomenon of elevated ambulatory blood pressure when clinic blood pressure is normal.
Children with masked hypertension had increased risk of left ventricular hypertrophy.
Also, ABPM can decrease the misdiagnosis of clinic hypertension from improper measurement technique, incorrect cuff size and patient anxiety.
Slide11Ambulatory blood pressure monitoring
Values:
It also allows measurement of changes in blood pressure variability and nocturnal dipping.
It can be used to classify hypertension.
Slide12Classification and staging of hypertension in children
Classification
Office BP
Mean ambulatory SBP or DBP
SBP or DBP load
Normotension
<90th percentile
<1.28 SDS
<95th percentile
<1.65 SDS
<25 %
White coat hypertension
≥95th percentile
≥1.65 SDS
<95th percentile
<1.65 SDS
<25 %
Pre-hypertension
≥90th percentile
≥1.28 SDS
or >120/90 mmHg
<95th percentile
<1.65 SDS
≥25 %
Masked hypertension
<95th percentile
<1.65 SDS
>95th percentile
>1.65 SDS
≥25 %
Ambulatory hypertension
>95th percentile
>1.65 SDS
>95th percentile
>1.65 SDS
25-50 %
Severe ambulatory hypertension
>95th percentile
>1.65 SDS
>95th percentile
>1.65 SDS
>50 %
Slide13Ambulatory blood pressure monitoring
Values:
It can be used to differentiate primary from secondary causes of hypertension in children.
Daytime diastolic blood pressure load >25% or asleep systolic blood pressure load >50% are both highly specific for diagnosing secondary hypertension in children.
It is frequently used to evaluate the effects of anti-hypertensive therapy.
It can be used to evaluate duration of action of medications and assess patient compliance.
Slide14Ambulatory blood pressure monitoring
Problems:
It can only be reliably performed and interpreted in children older than 5 years of age, although there have been successful trials to use it on younger children .
The normative values for ABPM were obtained on healthy European children, and some concerns have been raised that these norms may not apply to other populations.
Its device is prone to measurement errors if the device software is not properly maintained or updated.
The definition of the nighttime period on ABPM can be problematic.
Slide15Blood pressure variability and
rhythmicity
Slide16Blood pressure variability
The sympathetic nervous system plays an important in the regulation of blood pressure.
This is including the development and maintenance of sustained hypertension, by a chronically elevated central sympathetic tone in children.
Increased blood pressure variability may be associated with the progression of chronic kidney disease.
Children with chronic kidney disease and uncontrolled hypertension have higher systolic and diastolic blood pressure variability.
Slide17Blood pressure variability
Children with daytime SBP increased variability had a strong association with the left ventricular hypertrophy.
Moreover, there is evidence that an increased blood pressure variability in childhood is predictive of adult hypertension and early onset of atherosclerosis.
Slide18Blood pressure variability
Short-term variability:
Beat-to-beat blood pressure variability.
Long-term variability:
Day-to-day blood pressure variability.
Visit-to-visit blood pressure variability.
Slide19Assessment of blood pressure variability
Type
Method
Comment
Beat-to-beat BP variability
Continuous BP
short-term, measured by invasive intra-arterial BP
Day-to-day BP variability
Home BP
Long-term, measured by SD of BP readings
Visit-to-visit BP variability
Office BP
Long-term, measured by SD of BP readings
Ambulatory (24-h BP) variability
ABPM
Short-term, measured by SD of BP readings on ABPM
Slide20Blood pressure variability
The etiology of increased blood pressure variability is
multifactorial
.
The short-term variability (beat-to-beat) is associated with increased sympathetic nervous system activity, behavioral and emotional factors.
The long-term variability (day-by-day, visit-to-visit) results from decreased arterial compliance, improper dosing of antihypertensive medications and non-compliance to treatment .
Slide21Blood pressure rhythmicity
Blood pressure has a circadian rhythm or 24 hours rhythm.
It means that the blood pressure reaches its highest values during the awake time and then decrease to its lowest values during sleep (nocturnal dipping) in healthy individuals.
But, it was observed that significant alterations (absence of nighttime dipping)occur in children with hypertension and chronic kidney disease.
Slide22Blood pressure rhythmicity
Nocturnal administration of anti-hypertensive medication can restore a normal dipping and significantly reduced cardiovascular morbidity and mortality .
Slide23Different Methods for blood pressure assessment
Slide24Other Different Methods for blood pressure assessment
Office blood pressure measurement.
Home blood pressure measurement.
Slide25Different Methods for blood pressure assessment
Method
Measured parameter
Comment
Auscultatory
Auscultatory
phenomena (
Korotkoff
sounds) are caused by turbulent flow when the cuff pressure is less than the SBP (1st sound) and greater than the DBP (last sound)
Reference method for BP assessment
Operator dependent
Automated
Oscillations of arteries, mean arterial pressure is measured, the SBP and DBP are calculated by the device software
Less operator dependent
Widely used
Relies on device software
ABPM
Measurement of the BP during 24 hours including awake and asleep periods
BP level during 24 h, awake and asleep periods
BP dipping
BP load
Classification and staging of hypertension
Correlates with target organ damage and progression of chronic kidney disease
Slide26Ambulatory blood pressure monitoring
20 patients on regular
hemodialysis
for at least 6 months.
Age range from 5 to 13 years old.
9 females and 11 males.
5 patients did not complete the nighttime measurement.
Daytime SBP variability is high in 3 patients, DBP variability is high in 4 patients.
Nighttime DBP variability is high in one patient.
Degree of nocturnal fall (
nocturnal dipping)
:
Systolic and diastolic : 8 non-dipper, 5 night-
peaker
.
Slide27Ambulatory blood pressure monitoring and abnormalities of vascular structure in hypertension
Slide28Abnormalities of vascular structure and function in hypertension
Slide29Vascular structure
Ultrasound B-mode imaging is used to measure combined
intima
and media thickness (
cIMT
).
The carotid artery is the most widely imaged (most accessible and easy).
IMT correlated with higher daytime SBP index (measured with ABPM ), which indicates more severe hypertension.
Children with CKD were found to have a thicker
cIMT
which becomes higher with the increased severity of kidney disease.
Slide30Arterial stiffness
M-mode evaluation of the common carotid artery provides high quality images of the maximal (systolic) and minimal (diastolic) diameters for the calculation of carotid stiffness.
Increased carotid stiffness was found in pre-hypertensive young people before progression to sustained hypertension.
Similar to data on IMT, higher carotid stiffness in dialysis patients than patients with mild CKD.
After renal transplant, these abnormalities remain and correlate with higher blood pressure measured with ABPM.
Slide31Arterial stiffness
Non-ultrasound methods:
Cuff-based pressure device that measures resting brachial artery
distensibility
.
Pulse wave velocity measures the speed at which the bolus of blood travels along the arterial tree.
Augmentation index, which demonstrates features of central arterial stiffness and is high in children with CKD .
Ambulatory arterial stiffness index is another parameter calculated from a 24-h ABPM as 1 minus the slope of the regression of the 24-h SBP readings on the DBP readings.
Slide32Endothelial function
It is the ability of the endothelium to respond to stress.
Measured by ultrasound-based brachial flow-mediated dilation.
It is low in children with CKD and post-renal transplant.
Its lowest levels in young people on dialysis.
Discomfort occurs with inflating a blood pressure cuff on the forearm for 5 minutes to induce the ischemic stimulus.
Slide33Venous function
No difference between hypertensive patients
and controls in terms of venous function.
But higher venous pressure may be in the arms of hypertensive patients and greater reduction in venous compliance
.
Slide34Summary
Ambulatory blood pressure monitoring can be used for the diagnosis of hypertension as a cost-effective, safe, painless, non-invasive and accurate tool.
The assessment of blood pressure variability and
rhythmicity
is important in the choice and timing of antihypertensive therapy.
There is a relationship between blood pressure variability and the development of target organ damage.
Slide35Summary
ABPM should be considered in all children at risk for developing hypertension to apply preventive and therapeutic strategies early to avoid long term morbidity and mortality.
As, hypertension is one of the common causes of cardiovascular morbidity and mortality.
So, assessment of vascular structure and function is very important.
Slide36Thank you
Slide37REFERENCES
Awazu
M. Epidemiology of Hypertension in Children. In: Pediatric Nephrology.
Avner
ED, Harmon WE,
Niaudet
P, Yoshikawa N, Emma F and Goldstein SL, Springer 2016: 1907-1926.
Feber
J and
Litwin
M. Blood pressure assessment-from BP level to BP variability.
Pediatr
Nephrol
2016 ; 31:1071–1079.
Flynn J, Hayman L,
McCrindle
W and Zachariah J. Ambulatory Blood Pressure Monitoring in Children and Adolescents.
http://hyper.ahajournals.org
Updated: December 20, 2013, accessed October 21, 2015.
Urbina
EM. Abnormalities of vascular structure and function in pediatric hypertension.
Pediatr
Nephrol
2016; 31:1061–1070.