Systemic Hypertension

I. Definition

For adults, the 2017 Guidelines by the American College of Cardiology, American Heart Association, and several other organizations jointly revised the earlier definition and classification of hypertension (HTN) of 2003. The following are the new classification (Whelton et al., 2018). Table 23.1 shows different levels of blood pressure (BP) readings by the new definition of elevated BP.

  • 1.

    Normal BP is defined as <120 mm Hg systolic pressure (SP) and <80 mm Hg diastolic pressures (DP).

  • 2.

    SP between 120 and 129 mm Hg and DP <80 mm Hg are now called “elevated blood pressure,” formerly called “prehypertension.”

  • 3.

    Hypertension is classified as stage 1 and stage 2, depending on the level of abnormalities.

    • a.

      Stage 1 HTN is defined as SP 130 to 139 systolic mm Hg or DP 80 to 89 mm Hg.

    • b.

      Stage 2 HTN is defined as SP ≥140 mm Hg or DP ≥90 mm Hg.

    In children, hypertension is defined statistically, because BP levels vary with age and gender and because outcome-based data are not available for children. Following the new definition of hypertension in adults, the American Academy of Pediatrics updated the earlier guidelines of 2004 (Flynn et al., 2017) (see Table 23.1 ). In the new guidelines, the term “prehypertension” has been replaced with “elevated blood pressure” for children as in the adults.

  • 1.

    Normal BP is defined as systolic and diastolic pressure <90th percentile.

  • 2.

    Elevated BP is defined as an average systolic and diastolic pressure between the 90th and 95th percentiles for age and gender.

  • 3.

    HTN is defined as systolic or diastolic pressure levels that are greater than the 95th percentile for age and gender. As in adults, adolescents with BP levels ≥120/80 mm Hg by auscultatory method are considered hypertensive even if they are <95th percentile. HTN is further classified into stage 1 and stage 2.

    • a.

      Stage 1 HTN is present when BP readings are between 95th percentile and 99th percentiles + 12 mm Hg.

    • b.

      Stage 2 HTN is present when BP readings higher than 95th percentile + 12 mm Hg.

  • 4.

    White coat HTN is present when BP readings in health care facilities are greater than the 95th percentile but are normotensive outside a clinical setting. This condition may not be as benign as once thought to be and regular follow-up is now recommended. This topic is discussed further later in this chapter.

Table 23.1

Classification of Blood Pressure for Adults and Children

Adults a and Adolescent >13 Years b
SP (mm Hg) DP (mm Hg) Children and Adolescents <13 Years b
Normal BP <120 and <80 <90th %
Elevated BP 120-129 and <80

  • ≥90th% to <95th% or

  • ≥120/80 mm Hg, whichever is lower

Stage 1 HTN 130-139 or 80–89

  • ≥95th% to 95th% + 12 mm Hg or

  • 130/80 to 139/89 mm Hg (whichever is lower)

Stage 2 HTN ≥140 or ≥90

  • Higher than 95th% + 12 mm Hg or

  • ≥140/90 mm Hg (whichever is lower)

Blood pressure levels are based on an average of ≥2 careful readings or ≥2 occasions. Individuals with systolic and diastolic pressure in two different categories should be designated to the higher BP category.

BP , blood pressure; DP , diastolic pressure; HTN , hypertension; SP , systolic pressure; % , percentile.

a Adapted from Whelton, P. K., Carey, R. M., Aronow, W. S., et al, (2018). ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA guidelines for the prevention, detection, evaluation, and management of high blood pressure in adults: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Journal of the American College of Cardiology, 71 (10), e127-e248.

b Adapted from Flynn, J. T., Kaelber, D. C., Barker-Smith, C. M., et al. (2018). Clinical practice guideline for screening and management of high blood pressure in children and adolescents. Pediatrics, 140 (3), e20171904.

II. Normative BP Standards

  • 1.

    The BP tables provided by the Working Group of the National High Blood Pressure Education Program (NHBPEP) are not acceptable standards because they are obtained by a methodology currently unacceptable and are discordant from their own recommendations, statistically unsound, and impractical for practitioners (as discussed in Chapter 1 ).

  • 2.

    Normative BP standards from the San Antonio Children’s Blood Pressure Study (SACBPS) are the most reliable sets; they are the only large sets of BP standards obtained using the currently recommended methodology. In that study, both auscultatory and oscillometric (Dinamap 800) methods were used.

    • a.

      The auscultatory BP standards for children 5 to 17 years old are shown in Table B.3 , Table B.4 in Appendix B .

    • b.

      A different set of BP standards is needed for the oscillometric method because BP readings by Dinamap monitor model 8100, a popular oscillometric device, are significantly different from those obtained by the auscultatory method. Dinamap readings are on average 10 mm Hg higher for the SP and 5 mm Hg higher for the DP than readings using the auscultatory method.

      • (1)

        Normative oscillometric BP standards for children 5 to 17 years old from the SACBPS are presented in Table B.5 , Table B.6 in Appendix B .

      • (2)

        Oscillometric BP standards for neonates and small children up to 5 years of age are presented in Table 1.3 .

  • 3.

    Kaelber et al. (2009) have recommended a simplified table of BP levels according to age and gender (without height percentiles), above which further evaluation should be carried out for possible HTN. This approach is well justified and more practical because one does not need to use the unscientific normative standards of the NHBPEP and because height is not measured at some BP screening sites (as discussed in Chapter 2 ). Table 23.2 shows the 90th percentile BP values by both methods side-by-side. Table 23.2 is replication of Table 1.4 in Chapter 1 . It is interesting to note that the auscultatory BP levels recommended by Kaelbert et al. are almost the same as the 90th percentile of BP levels by the San Antonio study (Park et al., 2005).

    Table 23.2

    The 90th Percentiles of Blood Pressure by Auscultatory and Oscillometric Methods from the San Antonio Study

    Auscultatory a,b Oscillometric c
    Age (yr) Male Female Age (YR) Male Female
    5 103 60 102 60 5 115 68 114 68
    6 105 64 103 63 6 117 68 115 68
    7 107 66 104 65 7 118 69 116 69
    8 108 68 106 67 8 119 70 118 70
    9 109 68 108 67 9 121 70 119 70
    10 111 68 110 68 10 122 71 121 71
    11 113 68 112 68 11 124 71 122 71
    12 116 68 113 68 12 126 71 123 71
    13 118 68 115 68 13 129 71 125 71
    14 120 68 116 68 14 131 72 125 72
    15 120 69 117 69 15 133 72 126 72
    16 120 71 117 69 16 134 72 126 72
    17 120 73 118 70 17 134 72 126 72
    ≥18 120 73 120 70

    SP , systolic pressure; DP , diastolic pressure.

    a The 90th percentile of systolic pressure for males 14 years and older are higher than 120 mm Hg, but 120 mm Hg is listed in the table to be consistent with the definition of “elevated blood pressure” in adults.

    b Data from Park, M. K., Menard, S. W., & Yuan, C. (2001). Comparison of blood pressure in children from three ethnic groups. American Journal of Cardiology, 87 (11), 1305-1308.

    c Data from Park, M. K., Menard, S. W., & Schoolfield, J. (2005). Oscillometric blood pressure standards for children. Pediatric Cardiology, 26 (5), 601-607. These values were obtained by Dinamap model 8100 and in general fall between the 90th and 95th percentiles of blood pressure (prehypertension range).

III. Causes of Hypertension

  • 1.

    With the increasing prevalence of obesity in recent decades, overweight and obesity have become the most common causes of pediatric HTN.

  • 2.

    More than 90% of secondary HTN in nonobese children is caused by three conditions: renal parenchymal disease, renal artery disease, and COA.

  • 3.

    In general, children with essential HTN are older than 10 years, have mild HTN, and often are obese.

  • 4.

    Children with secondary HTN are generally younger than 10 years and have higher levels of BP. Children with secondary HTN rarely are obese and often are less than normal height.

  • 5.

    Table 23.3 lists the common causes of HTN by age group in (nonobese) children. Box 23.1 lists causes of secondary HTN.

    TABLE 23.3

    Common Causes of Chronic Hypertension According to Age

    Adapted from Task Force on Blood Pressure Control in Children. National Heart, Lung, and Blood Institute. (1987). Report of the second task force on blood pressure control in children. Pediatrics, 79 (1), 1-25.

    Age Group Causes
    Newborns Renal artery thrombosis, renal artery stenosis, congenital renal malformation, COA, bronchopulmonary dysplasia (transient)
    <6 yr Renal parenchymal disease, COA, renal artery stenosis
    6-10 yr Renal artery stenosis, renal parenchymal disease, COA
    >10 yr Primary hypertension, renal parenchymal disease

    COA , coarctation of the aorta.

Apr 11, 2021 | Posted by in CARDIOLOGY | Comments Off on Systemic Hypertension

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