Systolic or Diastolic Blood Pressure Significance

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PEDIATRICS (ISSN 0031 4005). Copyright © 1988 by the American Academy of Pediatrics.

112 PEDIATRICS Vol. 82 No. 1 July 1988

COMMENTARY

Opinions expressed in this commentary are those of the authors and not necessarily those of the American Academy of Pediatrics or its Committees.

Systolic

or Diastolic

Blood

Pressure

Significance

The importance of hypertension has been nec-ognized from the complications it produces in adults, mainly stroke, congestive heart failure, myocardial infarction, and renal failure. ‘‘#{176} Sim-ilan health consequences have been reported in a few children with severe hypertension. As a result of these health concerns, children’s health care providers have been encouraged to determine and record blood pressures of their young patients. It has become customary to consider hypertension

in adults in terms of an empirically designated

diastolic blood pressure. Is this practice valid? Should this practice be applied to children? Un-fortunately, these questions cannot be answered in reference to children, because there have been no long-term studies relating height ofblood pres-sure to vascular sequelae in children. In the ab-sence of such data, results of studies performed in adults have been extrapolated to children.

Epidemiologic data from various studies in

adults indicate a greaten association of morbid

vascular events with systolic rather than diastolic pnessure.’’#{176} Gubnen”2 has shown that at any level of diastolic pressure cardiovascular

mortal-ity increases in proportion to the associated

sys-tolic pressure. Studies from Framingham con-firmed these results for stroke,3 coronary heart disease,4 left ventricular hypentnophy,5 and congestive heart failure.5 Similarly, isolated sys-tolic hypertension is associated with increased cardiovascular mortality, mostly stroke,6 and is independent of so called “arterial It should not be surprising that these events are as-sociated most closely with systolic pressure. Re-flection on cardiac physiology would lead one to expect that congestive heart failure and

ventnic-ular hypentrophy would be more closely related to systolic pressure, the major determinant of left ventricular afterload. Likewise, intracranial hemorrhage should correlate best with the peak arterial pressure.8 Thus, both physiologic and epi-demiologic observations confirm a closer link of cardiovascular morbidity to systolic rather than diastolic pressure.9

Therapeutic studies indicate equally predictive effects of systolic and diastolic blood pressure in hypertensive vascular disease. The Veterans

Ad-ministration Cooperative Study Group’1 and the

Oslo study12 found that patients with systolic

pressure greaten than 165 mm Hg on 160 mm Hg,

respectively, had the highest incidence of vascular events. No difference was found between systolic and diastollic pressure relative to prediction of cardiovascular morbidity in either of these

stud-ies, as well as others.’3”4 Four recent studies

(Re-port of the Joint National Committee on Detec-tion, Evaluation, and Treatment of High Blood

Pressure,’5 the Hypertension Detection and

Fol-lowup Program,’6 the Medical Research Trial of Treatment of Mild Hypertension,’7 and the Aus-tralian Therapeutic Trial in Mild Hypertension’8) referred only to diastolic pressure or did not ana-lyze systolic and diastolic pressures separately. One ofthese studies,’5 “while recognizing the epi-demiologic data regarding increased risk from ele-vated systolic pressure at all ages,” chose diastolic blood pressure as the basis for diagnosis and then-apy because “the benefits of treatment of systolic pressure are unclear.” Omitting systolic pressure from analysis in therapeutic studies because

“ben-efits of treating systolic pressure are unclean”

then becomes a “catch-22” in that the benefits of treatment and significance of systolic pressure will never be known.

Ofconsidenable importance to this argument re-garding the relative importance of systolic v

dia-stolic blood pressure is the observation that dia-stolic pressure is considerably more difficult to

determine than systolic pressure by all indirect methods. Muffling of the vascular wall tapping

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COMMENTARY 113

sound (phase IV Korotkom is subject to

consid-enable observer variation.’9 It is also often

diffi-cult to determine the exact point of disappearance of the tapping sound (phase V Korotkoff).’9’2#{176}

Comparison of indirect pressure determination to

direct intraarterial readings also confirms the de-creased accuracy of the indirect diastolic reading

relative to systolic.2’24 In addition, the systolic pressure is subject to less intrasubject variation than is diastolic pressure.25 In fact, large

vania-tion in diastolic pressure readings can result

solely from variation in the pressure ofthe stethe-scope on the antecubital fossa in children.26

Fur-thermone, even if fourth and fifth Korotkoff

phases could be clearly determined, there as yet is no consensus concerning which Korotkoff phase is associated with diastolic pressure in childhood.

The Task Force nomograms27 use the fourth

phase Korotkoff as diastolic pressure in infants

and children through aged 12 years. The fifth

phase Konotkoff is used as the diastolic pressure in adolescents aged 13 through 18 years.

These arguments are even more pertinent when one addresses blood pressure determinations in

small infants. Standard auscultatony blood

pres-sure determinations are extremely difficult in

small infants. As a consequence, Doppler and

os-cillometnic techniques have been developed for

in-fants and are the methods used for indirect blood pressure determinations in infant and pediatric intensive care units. Although these blood

pres-sure recording devices determine accurate

sys-tolic blood pressure, they have not been

docu-mented to record diastolic pressure accurately. The observation that even small amounts of

pnes-sure applied to the stethescope head at the

an-tecubital fossa artificially lowers the phase V Korotkoff26 is important in that regard. Many au-tomated devices have the detection device at-tached to the undersurface of the cuff where it

may be placed under excessive pressure. Diastolic

blood pressure measurements with such

instru-ments would be expected to be of questionable

ac-curacy. Because automated devices are used in

both adults and children to determine blood

pres-sure and are gaining in popularity with the lay

public, it is a disservice to these patients to in-appropriately emphasize diastolic pressure in

di-agnosis and therapy of hypertension.

Thus, systolic blood pressure is more predictive

of cardiovascular morbidity in adults, is easier to obtain, and is more reproducible than diastolic

pressure. As a result of these observations, some

have recommended omission of recording of dia-stolic pressure altogether.28 It would seem pru-dent for the pediatrician to pay close attention to

the systolic pressure in young patients. Until

fun-then data are gathered, diagnosis and prognosis

of childhood hypertension should be based on the

recording of both systolic and diastolic pressures,

with the deficiencies of diastolic pressure kept firmly in mind.

DOUGLAS N. WEISMANN, MD

Department of Pediatrics

The University of Iowa Hospitals and Clinics Iowa City

REFERENCES

1. Gubner RS: Life expectancy in the young hypertensive, in Brest AN, MoyerJH (eds): Hypertension: RecentAdvances.

Philadelphia, Lea & Febiger, 1961, pp 18-23

2. Gubner RS: Systolic hypertension: A pathogenetic entity: Significance and therapeutic considerations. Am J Cardiol

1962;9:773-776

3. Kannel WB, Wolf PA, Verter J, et al: Epidemiologic as-sessment of the role of blood pressure in stroke: The Fra-mingham study. JAMA 1970;214:301-310

4. Kannel WB, Gordon T, Schwartz MJ: Systolic versus dia-stolic blood pressure and risk of coronary heart disease: The Framingham study. Am J Cardiol 1971;27:335-346

5. Kannel WB, Castelli WP, McNamara PM, et al: Role of

blood pressure in the development of congestive heart fail-ure: The Framingham study. NEnglJMed 1972;287:781-787

6. Colandrea MA, Friedman GD, Nichaman MZ, et al: Sys-tolic hypertension in the elderly: An epidemiologic as-sessment. Circulation 1970;41:239-245

7. Kannel WB, Wo1fPA, McGee DL, et al: Systolic blood pres-sure, arterial rigidity and risk of stroke: The Framington Study. JAMA 1981;245:1225-1229

8. Koch-Weser J: The therapeutic challenge of systolic hy-pertension. N EngI J Med 1973;289:481-483

9. Kannel WB, Dawber TR: Hypertension as an ingredient of a cardiovascular risk profile. Br J Hosp Med 1974; 11:508-523

10. Society ofActuaries: Build andBloodPressure Study. Chi-cago, Society of Actuaries, 1959

1 1. Veterans Administeration Cooperative Study Group on Anti-hypertensive Agents: Effects of treatment on mor-bidity in hypertension: II. Results in patients with dia-stolic blood pressure averaging 90 through 114 mm Hg.

JAMA 1970;213:1143-1152

12. Helgeland A: Treatment of mild hypertension: A five year

controlled drug trial: The Oslo Study. Am J Med

1980;69:725-732

13. Caidwell JR, Schork MA, Aiken RD: Is near basal blood pressure a more accurate predictor of cardiorenal mani-festations of hypertension than casual blood pressure? J Chronic Dis 1978;31:507-512

14. Anderson TW: Re-examination of some of the

Fra-mingham blood-pressure data. Lancet 1978;1:1139-1141 15. Joint National Committee on Detection, Evaluation, and

Treatment ofHigh Blood Pressure: Report ofthe Joint Na-tional Committee on Detection, Evaluation and Treatment

of High Blood Pressure: A cooperative study. JAMA

1977;237:255-261

16. Hypertension Detection and Followup Program Coopera-tive Group: Five-year findings ofthe Hypertension Detec-tion and Follow-up Program: III. Reduction in stroke in-cidence among persons with high blood pressure. JAMA

1982;213:1143-1152

17. Medical Research Council Working Party: MRC trial of treatment of mild hypertension: principal results. Br Med J 1985;291:97-104

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114 PEDIATRICS Vol. 82 No. 1 July 1988

18. The Management Committee ofthe Australian Therapeu-tic Trial in Mild Hypertension: The Australian Therapeu-tic Trial in Mild Hypertension: Report by the Management Committee. Lancet 1980;1:1261-1267

19. Subcommittee of the AHA Postgraduate Education Com-mittee: Recommendations for Human Blood Pressure De-termination by Sphygmomanometers. Dallas, American Heart Association, 1980

20. Berliner K, Fujiy H, Holee D, et al: The accuracy of blood pressure determinations: A comparison of direct and in-direct measurements. Cardiologia 1960;37:118-128

21. Steinfeld L, Dimich I, Reder R, et al: Sphygmomanometry in the pediatric patient. J Pediatr 1978;92:934-938

22. Spence JD, Sibbold WJ, Cape RD: Pseudohypertension in the elderly. Clin Sci Mol Med 1978:55(suppl):399s-402s

23. Littler WA, Honour AJ, Pugsley DJ, et al: Continuous re-cording ofdirect arterial pressure in unrestricted patients: Its role in the diagnosis and management of high blood pressure. Circulation 1975;51:1101-1106

24. Van Bergen FH, Weatherhead DS, Treloar AE, et al: Com-parison of indirect and direct methods of measuring ar-terial blood pressure. Circulation 1954;10:481-490

25. Jorde LB, Williams RR: Innovative blood pressure mea-surements yield information not reflected by sitting mea-surements. Hypertension 1986;8:252-257

26. Londe 5, Klitzner TS, Moss AJ: Effects ofpressure exerted on the stethescope head on auscultatory blood pressure, in Loggie JMH, Horan MJ, Grushkin AB, et al (eds): NHLBI Workshop in Juvenile Hypertension. Proceedings from a Symposium. New York, Biomedical Information Corp,

1984, pp 107-109

27. Task Force on Blood Pressure Control in Children: Report of the Second Task Force on Blood Pressure Control in Children-1987. Pediatrics 1987;79:1-25

28. Fisher CM: The ascendency ofdiastolic blood pressure over systolic. Lancet 1985;2:1349-1350

GOVERNMENT AT LAST GIVES SOMETHING TO THE HAEMOPHILIA SOCIETY

The Government has finally recognised that something out of the ordinary

must be done to relieve the appalling plight of 1200 haemophiliac patients

who were infected with HIV as a result of . . . treatment with contaminated

factor VIII. Earlier this week the Health Minister . . . announced that he was

making an ex-gratia grant of #{163}10million to enable the Haemophilia Society to establish a special trust fund. The money will be used to help the victims with the additional costs of coping with two life-threatening disorders. . .

So fan 66 have developed full AIDS and 49 of them have died. Among the

rest of the 1200, many are ill and unable to work. Some have infected their

wives. None can get life insurance to safeguard their families on mortgage protection for their homes.

From Carvel J: Commentary from Westminster. Lancet 1987;2:1223.

Submitted by Student

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1988;82;112

Pediatrics

DOUGLAS N. WEISMANN

Systolic or Diastolic Blood Pressure Significance

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1988;82;112

Pediatrics

DOUGLAS N. WEISMANN

Systolic or Diastolic Blood Pressure Significance

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