Hypertension in children and adolescents Vidar Edvardsson, MD Children´s Medical Center Landspitali University Hospital Reykjavik, Iceland
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.
Prevalence of Hypertension in 9 to 10-year-old Icelandic School Children Sandra D Steinthorsdottir, Sigridur B Eliasdottir, Olafur S Indridason, Inger M Agustsdottir, Runolfur Palsson, Vidar O Edvardsson Prevalence of elevated blood pressure after the first, second and third blood pressure screening sessions.
Prevalence of Hypertension in 9 to 10-year-old Icelandic School Children Sandra D Steinthorsdottir, Sigridur B Eliasdottir, Olafur S Indridason, Inger M Agustsdottir, Runolfur Palsson, Vidar O Edvardsson Correlation between body mass index (BMI) and mean systolic blood pressure (r=0.26, p=<0.001).
Prevalence of Hypertension in 9 to 10-year-old Icelandic School Children Sandra D Steinthorsdottir, Sigridur B Eliasdottir, Olafur S Indridason, Inger M Agustsdottir, Runolfur Palsson, Vidar O Edvardsson Prevalence of elevated blood pressure at the first, second and third screening sessions, categorized by body mass index percentiles (first screening, p <0.001; second screening, p=0.002; third screening, p=0.007).
Orsakir háþrýstings í nýburum, eldri börnum og unglingum 1Tólf mánaða og yngri. 2Svipaðar undirliggjandi ástæður og hjá börnum á skólaaldri. 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.
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.