Hypertension in children and
adolescents
Vidar Edvardsson, MD
Children´s Medical Center
Landspitali University Hospital
Reykjavik, Iceland
What is normal BP for which
age?
Skilgreiningar
•
•
•
Eðlilegur blóðþrýstingur – efri og neðri mörk
blóðþrýstings <90% fyrir aldur og kyn.
Forstig háþrýstings – efri og neðri mörk
blóðþrýstings milli 90 og 95% fyrir aldur og kyn
eða 120/80 í táningum.
Háþrýstingur – efri og neðri mörk blóðþrýstings
>95% fyrir aldur og kyn.
–
–
Vægur háþrýstingur ≤5 mm yfir 99. percentíli
blóðþrýstings fyrir aldur og kyn.
Alvarlegur háþrýstingur >5 mm yfir 99. percentíli
blóðþrýstings fyrir aldur og kyn.
–Pediatrics (2004) Vol. 114 No.2 Definition from 4th report on the diagnostic,
evaluation & treatment of high blood pressure in children and adolescents
Greining
• Gangið úr skugga um að þrýstingur sé rétt
mældur en röng blóðþrýstingsmæling er
algengasta ástæða fyrir ranglega greindum
háþrýstingi.
• Mælið blóðþrýsting nokkrum sinnum og látið að
minnsta kosti einhverja daga líða á milli mælinga
ef blóðþrýstingshækkun er væg.
• Ein há blóðþrýstingsmæling dugar ekki til þess
að greina háþrýsting. Nauðsynlegt er að mælast
að minnsta kosti þrisvar sinnum með hækkaðan
þrýsting á 2ja vikna tímabili til þess að greinast
með háþrýsting.
Orsakir háþrýstings í nýburum, eldri börnum og unglingum
Infants1
Schoolage
Adolescents
Primary/Essential
<1%
15-30%
85-95%
Secondary
99%
70-85%
5-15%2
Renal Parenchymal Disease
20%
60-70%
Renovascular
25%
5-10%
1%
3-5%
Aortic Coarctation
35%
10-20%
Reflux Nephropathy
0%
5-10%
Neoplastic
4%
1-5%
Miscellaneous
20%
1-5%
Endocrine
1Tólf
mánaða og yngri.
undirliggjandi ástæður og hjá börnum á skólaaldri.
2Svipaðar
Flynn JT. Hypertension in childhood and adolescence. In: Kaplan NM, Kaplan's Clinical Hypertension,
9th ed. Philadelphia, PA: Lippincott-Williams and Wilkins, 2005, pp. 465-488.
Prevalence
• Data from the National Health and Nutrition
Examination Survey (NHANES) have indicated
– that 50 million (20%) or more Americans have high
blood pressure (BP) warranting some form of
treatment (Burt, Hypertension. 1995 and Hajjar JAMA. 2003)
• Worldwide prevalence estimates of HTN
– as many as 1 billion (1x109) individuals may be
affected (World Health Report 2002 http://www.who.int/whr/2002 )
Prevalence in children
and adolescents
• In studies carried out in the 70’s, prevalence of
HTN was approximately 2%
• Lauer, Muscatine study (J Pediatr 1975)
• Silverberg, (Can Med Assoc J 1975)
• Fixler, Dallas study (Pediatrics 1979)
• In a recent study by Sorof et al (Pediatrics 2004)
– The prevalence of HTN
• was 4.5% in 5102 school children age 13.5 +/- 1.7 years
• increased progressively as BMI increased from ≤5th
percentile (2%) to ≥95th percentile (11%).
– When corrected for BMI, ethnic predisposition for
HTN was not detected
Blood pressure in children
“tracks” into adulthood
• In the Muscatine study (Lauer, Pediatrics 1989)
– Children with SBP >90% were 3.9 times more likely to
be hypertensive as adults.
– Children with DBP >90% were 1.9x more likely to
have hypertension in adult life.
– The absence of abnormal BP readings in childhood
predicted normal adult blood pressure.
• The Bogalusa Heart Study (Bao, Am J Hypertens 1995)
– prevalence of clinically diagnosed hypertension in
young adults was much higher in subjects whose
childhood BP was in the top quintile.
Morbidity and mortality related to
hypertension in adults
• Suboptimal blood pressure is the number
one risk factor for death throughout the
world
– Approximately 7.1 million deaths per year
may be attributable to hypertension
• Suboptimal BP (>115 mm Hg SBP) is
responsible for 62% of cerebrovascular
disease and 49% of ischemic heart
disease, with little gender variation
(World Health Report 2002 http://www.who.int/whr/2002)
Complications of long-standing
hypertension in children
• Autospy studies confirm that athero-sclerosis
starts in childhood or adolescence.
– McGil, Arterioscler Thromb Vasc Biol. 2000
• Children rarely develop the severe
cardiovascular and renal complications of
persistent hypertension.
• Other target organ effects of long-standing
hypertension in childhood are, however, well
established.
End-organ damage
Organ damage in
hypertensive children
• Persistent hypertension causes left
ventricular hypertrophy and increased
arterial intima-media thickness in children.
• Hypertensive retinal changes, although not
extensively studied in children, do exist.
• Microalbuminuria and chronic renal failure
may occur in children and adolescents
with long-standing and/or severe blood
pressure elevation.
Left ventricular hypertrophy and
future cardiovascular events
• LVH has been established as an
independent predictor of cardiovascular
events in adults (Koren, Ann Intern Med 1991; Brown, Am
Heart J 2000; Levy, N Engl. Med 1990).
• In adults, LVH (LVMI >51g/m2.7) confers a
fourfold risk of CVE (de Simone 1995 J Am
Coll Cardiol).
• In children
– LVH is defined as LVMI >95%
– Severe LVH is defined as LVMI >99%
LVH and cardiovascular
events in children
• Although outcome-based standards for
LVMI are not available in children
– LVH has been used as a marker to identify
hypertensive children at risk for future
cardiovascular events.
• (Brown, Am Heart J 2000; Levy, N Engl. Med 1990)
Carotid intima-media thickness
• cIMT is an independent predictor of CVD in
adults.
• Prospective studies in adults suggest that every
0.1-mm increase in cIMT increases the risk of
future coronary events by 30%.
– (Bots, Circulation 1997; Hodis, Ann Intern Med 1998)
• Data from longitudinal studies suggest that cIMT
in adults is signifcantly correlated with
cardiovascular risk factors already present in
childhood.
– (Raitakari, JAMA 2006)
.
Effects of childhood primary HTN on carotid intima
media thickness: a matched controlled study
• 28 hypertensive children underwent an evaluation of
their cIMT, LVM index and had ambulatory blood
pressure monitoring performed.
– Control subjects were matched pairwise for BMI.
– In the hypertensive subjects, cIMT correlated strongly
with daytime systolic blood pressure index.
– The median cIMTmedia thickness of hypertensive
subjects was greater than that of matched controls
(0.67 versus 0.63 mm; P0.045).
– These results provide strong evidence that carotid
intima media thickness is increased in childhood
primary hypertension, independent of the effects of
obesity.
Lande, Hypertension 2006
Cardiovascular risk factors in childhood and carotid
artery intima-media thickness in adulthood
• The Cardiovascular Risk in Young Finns Study
• The purposes of the study was to investigate the
relationship between CV risk factors measured
in childhood and adolesence and cIMT
measured in adults
• A population based, prospective, cohort study
that included 2229 adult Finns aged 24-39
years, who were first examined at the ages 3-18
years and followed up 21 years later.
Raitakari, JAMA 2006
Cardiovascular risk factors in childhood and carotid
artery intima-media thickness in adulthood
• Major findings: Carotid intima-media
thickness in adulthood was significantly
associated with LDL-C, SBP, BMI and
smoking at the age of 12-18 years, and
with adult SBP, BMI and smoking.
Raitakari, JAMA 2006
Cardiovascular risk factors in childhood and carotid
artery intima-media thickness in adulthood
• Conclusion: Risk factor profile assessed in
12-18 year old adolescents predicts adult
comon cIMT in subjects aged 33-39 years
(in both men and women).
Raitakari, JAMA 2006
Microalbuminuria
• Microalbuminuria is associated with CVD
in hypertensive adult patients
– Jager, Arterioscler Thromb Vasc Biol 1999
• Not much is written on micro-albuminuria
in non-diabetic children with hypertension.
Hypertensive retinopathy
• High childhood blood pressure (SBP) is, associated with
retinal arteriolar narrowing (population based study of 1572
children; Mitchell, Hypertension 2007).
• Daniels et al (Am J Ophthalmol 1991) found evidence of
retinopathy in 50 (51%) of 97 children and adolescents
with essential hypertension.
• Skalina (J Pediatr 1983) reported retinopathy in 50% of
newborns with hypertension, that resolved with
resolution of hypertension.
• A number of authors have described various retinal
abnormalities, including decreased visual acuity and or
blurred vision and papilledema, in patients with very high
blood pressure.
Summary
• Target organ damage is common in children and
adolescents with hypertension.
• Obesity is a major risk factor for hypertension
and vascular damage in the pediatric age group.
• As many as 40% of hypertensive patients may
have left ventricular hypertrophy and signs of
arterial hypertensive damage at diagnosis.
• Surrogate markers of atherosclerosis in young
adults are strongly correlated with hypertension
and other cardiovascular risk factors in
childhood.
• Anti-hypertensive therapy induces regression of
left ventricular hypertrophy and other end-organ
damage.
Recommendations
• All children with established hypertension should
be screened for left ventricular hypertrophy and
retinopathy where expertise is available.
– The routine screening for microalbuminuria is
currently not recommended by the US-NHBPEP.
– Weight reduction should be attempted in all
overweight hypertensive patients.
• Anti-hypertensive therapy
– LVH and other target organ damage should be an
indication for aggressive antihypertensive therapy.