EDITOR'S COLUMN
Blood pressure
OVER THE PAST TWO DECADES it h a s b e c o m e i n c r e a s -
ing!y clear that hypertension is one Of the most ubiquitous of diseases. It is estimated that one in ten adult Americans has an elevated blood pressure. Surveys have shown that only half of this hypertensive population is aware of their hypertension, and less than one in four is receiving adequate treatment. In the past much attention has been focused upon recognition and treatment of "curable" hypertension, secondary to specific causes such as pheochromocytoma, Cushing syndrome, or renovascular disease. Recognition and proper treatment of these relatively uncommon forms of hypertension, may result in dramatic Shifts in blood pressure. Benign, essential hypertension has received less attention for a variety of reasons. Some physicians are still uncertain whether therapy with antilaypertensive drugs will prevent the development of cardiovascular complications. Other physicians may not be Convinced that the benefits of treatment outweigh the known side effects of currently available drugs. The potential benefits of treatment are even less clear in pediatric practice, since there is often a long latency period between discovery of elevated blood pressure in a child and the development of overt comphcations. In Evans County, Georgia, a group of 50 adolescents and young adults who had an average blood pressure reading of greater than 140 mm Hg systolic or 90 mm Hg diastolic were selected for follow-up study: After seven years, 30 members of this group were evaluated. Two deaths from cerebral hemorrhage had occurred and one patient had known hypertensive heart disease. Sustained hypertension with cardiovascular and cerebrovascular synqptoms had developed in three others, and 12 had severe but asymptomatic hypertension. Only 12 of the 30 had become normotensive. An increase in blood pressure during puberty has sometimes been thought to be secondary to sexual m~ituration and therefore of little cl!nical significance. The study by Londe and associates, 2 in this issue of THE JOURNAL re-examines the relationship Of blood pressure to sexual maturation. Blood pressure readings were not higher in patients with more advanced sexual development nor were there significant correlations with serum
FSH or LH levels in the patients studied. Thi s study, like many others, shows a better correlation of the features studied With systolic BP than With diastolic BP. This should not be surprising, since comparisons of intraarterial measurements of blood pressure with measurements by various indirect techniques have uniformly shown that the correlation of external and intra-arterial systolic BP is relatively satisfactory, but that the correlation with diastolic BP is poor? See related article, p. 896.
Abbreviations used BP: blood pressure FSH: follicle-stimulating hormone LI-I; luteinizinghormone Another important aspect of this study is that the authors' data are limited to cross-sectional measurements rather than to longitudinal evaluations. It would seem to me that many of the errors of sphygmomanometry would be minimized bY using the same patient as a control, as was done in the excellent study by Shock? AS Shock points out, the measured BP depends to some extent on the techniques used, such as the speed of compression and deflation of the cuff, the size of the arm in relation to the size o f the cuff, tile position of the arm in relation to the body, the criteria used to estimate BP, the interpretation of auscultatory sounds, the degree of apprehension Of the subjects, and the amount of rest permitted the subjects before the measurements are made. Blood pressure as assessed by sphygmQmanometry is also influenced by the compressibility of the intervening tissues and the elasticity of the arterial wall. Part of the correlation of elevated BPs with obesity may be artifactuall In contrast to the study by Londe and associates,~ Shock found a distinCt increase in systolic BP which appeared suddenly and developed rapidly after the children reached the age of 131/2 or 14 years. Another difference between the studies of Shock and Londe and associates is that Shock utilized the average of four measurements, two of which were taken on each of two separate days. Londe and associates, in contrast, The Journal o f P E D I A T R I CS Vol. 87, No. 6, part 1, pp. 1013-1014
10i3
1014
Editor's column
attempted to determine BP "under office conditions." The first determination of systolic and diastolic pressure was used unless the reading "seemed high, in which case two more readings were taken and the lowest of the obtained values was used. ''~ Since the m e a n is the most likely to be correct in a series of values, standard statistical practice would include all values determined unless one has reason to suspect that there is a technical error in determining one (or more) of the readings, in which case that reading may be excluded. For the reasons stated it seems that we still do not have a definitive answer on the effects of puberty on BP. Certainly the paper by Londe and associates raises the possibility that a BP elevation seen in adolescents cannot be assumed to be related to the onset of puberty. What then should a pediatrician do when he discovers an elevated BP reading in a child or adolescent? (1) He should arrange to have the BP taken on several more occasions with the child in as basal a condition as possible: (2) If repeated readings of the BP continue to be elevated, he should t h e n institute a search for the etiology a n d initiate appropriate treatment. (3) If the BP is elevated on only a few readings, it would seem wisest to continue observation and repeat measurements of BP on subsequent office visits. The true significance of labile hypertension is not k n o w n . The study done in Evans County, Georgia, cited above and an earlier study of hypertension among army officers would indicate that even a single detection of an elevated BP is associated with a significant increase in mortality rate? One other point should be made. For epidemiologic studies, such as that of Londe and associates, single BP
The Journal of Pediatrics December 1975
readings are adequate, if the study group is large enough. In childhood, this would m e a n including an u n d u l y high proportion of patients with labile hypertension, which must be taken into account in the design and analysis of the study. For the individual patient, however, the presence of even a single elevated BP should not be dismissed in an offhand manner. Until more data are accumulated on the natural history of labile hypertension, it would seem prudent to explain the situation to the parents and to repeat BP determinations at subsequent visits. Only in that way can the pediatrician be assured that the occasional elevated BP reading is truly of benign origin. L. Jerome Krovetz Department of Pediatrics University o f Virginia Medical Center Charlottesville, Va. 22901
REFERENCES
1~ Heyden S, et al: Elevated blood pressure levels in adolescents, Evans County, Georgia, JAMA, 209:1683, 1969. 2. Londe S, Johanson A, Kronemer NS, and Goldring D: Blood pressure and puberty~ J PEDzATR87:896, 1975. 3. MOSSAJ, and Adams FH: Index of indirect estimation of diastolic blood pressure, Am J Dis Child 106:364, 1963. 4. Shock NW: Basal blood pressure and pulse rate in adolescents, Am J Dis Child 68:16, 1944. 5. Londe S, Bourgoignie JJ, Robson AM, and Goldring D: Hypertension in apparentIy normal children, J PEmATR 78:569, 1971. 6. Levy RL, et al: Transient hypertension: Its significance in terms of later development of sustained hypertension and cardiovascular renal disease, JAMA 126:829, 1944.
Blood pressure
OVER THE PAST TWO DECADES it h a s b e c o m e i n c r e a s -
ing!y clear that hypertension is one Of the most ubiquitous of diseases. It is estimated that one in ten adult Americans has an elevated blood pressure. Surveys have shown that only half of this hypertensive population is aware of their hypertension, and less than one in four is receiving adequate treatment. In the past much attention has been focused upon recognition and treatment of "curable" hypertension, secondary to specific causes such as pheochromocytoma, Cushing syndrome, or renovascular disease. Recognition and proper treatment of these relatively uncommon forms of hypertension, may result in dramatic Shifts in blood pressure. Benign, essential hypertension has received less attention for a variety of reasons. Some physicians are still uncertain whether therapy with antilaypertensive drugs will prevent the development of cardiovascular complications. Other physicians may not be Convinced that the benefits of treatment outweigh the known side effects of currently available drugs. The potential benefits of treatment are even less clear in pediatric practice, since there is often a long latency period between discovery of elevated blood pressure in a child and the development of overt comphcations. In Evans County, Georgia, a group of 50 adolescents and young adults who had an average blood pressure reading of greater than 140 mm Hg systolic or 90 mm Hg diastolic were selected for follow-up study: After seven years, 30 members of this group were evaluated. Two deaths from cerebral hemorrhage had occurred and one patient had known hypertensive heart disease. Sustained hypertension with cardiovascular and cerebrovascular synqptoms had developed in three others, and 12 had severe but asymptomatic hypertension. Only 12 of the 30 had become normotensive. An increase in blood pressure during puberty has sometimes been thought to be secondary to sexual m~ituration and therefore of little cl!nical significance. The study by Londe and associates, 2 in this issue of THE JOURNAL re-examines the relationship Of blood pressure to sexual maturation. Blood pressure readings were not higher in patients with more advanced sexual development nor were there significant correlations with serum
FSH or LH levels in the patients studied. Thi s study, like many others, shows a better correlation of the features studied With systolic BP than With diastolic BP. This should not be surprising, since comparisons of intraarterial measurements of blood pressure with measurements by various indirect techniques have uniformly shown that the correlation of external and intra-arterial systolic BP is relatively satisfactory, but that the correlation with diastolic BP is poor? See related article, p. 896.
Abbreviations used BP: blood pressure FSH: follicle-stimulating hormone LI-I; luteinizinghormone Another important aspect of this study is that the authors' data are limited to cross-sectional measurements rather than to longitudinal evaluations. It would seem to me that many of the errors of sphygmomanometry would be minimized bY using the same patient as a control, as was done in the excellent study by Shock? AS Shock points out, the measured BP depends to some extent on the techniques used, such as the speed of compression and deflation of the cuff, the size of the arm in relation to the size o f the cuff, tile position of the arm in relation to the body, the criteria used to estimate BP, the interpretation of auscultatory sounds, the degree of apprehension Of the subjects, and the amount of rest permitted the subjects before the measurements are made. Blood pressure as assessed by sphygmQmanometry is also influenced by the compressibility of the intervening tissues and the elasticity of the arterial wall. Part of the correlation of elevated BPs with obesity may be artifactuall In contrast to the study by Londe and associates,~ Shock found a distinCt increase in systolic BP which appeared suddenly and developed rapidly after the children reached the age of 131/2 or 14 years. Another difference between the studies of Shock and Londe and associates is that Shock utilized the average of four measurements, two of which were taken on each of two separate days. Londe and associates, in contrast, The Journal o f P E D I A T R I CS Vol. 87, No. 6, part 1, pp. 1013-1014
10i3
1014
Editor's column
attempted to determine BP "under office conditions." The first determination of systolic and diastolic pressure was used unless the reading "seemed high, in which case two more readings were taken and the lowest of the obtained values was used. ''~ Since the m e a n is the most likely to be correct in a series of values, standard statistical practice would include all values determined unless one has reason to suspect that there is a technical error in determining one (or more) of the readings, in which case that reading may be excluded. For the reasons stated it seems that we still do not have a definitive answer on the effects of puberty on BP. Certainly the paper by Londe and associates raises the possibility that a BP elevation seen in adolescents cannot be assumed to be related to the onset of puberty. What then should a pediatrician do when he discovers an elevated BP reading in a child or adolescent? (1) He should arrange to have the BP taken on several more occasions with the child in as basal a condition as possible: (2) If repeated readings of the BP continue to be elevated, he should t h e n institute a search for the etiology a n d initiate appropriate treatment. (3) If the BP is elevated on only a few readings, it would seem wisest to continue observation and repeat measurements of BP on subsequent office visits. The true significance of labile hypertension is not k n o w n . The study done in Evans County, Georgia, cited above and an earlier study of hypertension among army officers would indicate that even a single detection of an elevated BP is associated with a significant increase in mortality rate? One other point should be made. For epidemiologic studies, such as that of Londe and associates, single BP
The Journal of Pediatrics December 1975
readings are adequate, if the study group is large enough. In childhood, this would m e a n including an u n d u l y high proportion of patients with labile hypertension, which must be taken into account in the design and analysis of the study. For the individual patient, however, the presence of even a single elevated BP should not be dismissed in an offhand manner. Until more data are accumulated on the natural history of labile hypertension, it would seem prudent to explain the situation to the parents and to repeat BP determinations at subsequent visits. Only in that way can the pediatrician be assured that the occasional elevated BP reading is truly of benign origin. L. Jerome Krovetz Department of Pediatrics University o f Virginia Medical Center Charlottesville, Va. 22901
REFERENCES
1~ Heyden S, et al: Elevated blood pressure levels in adolescents, Evans County, Georgia, JAMA, 209:1683, 1969. 2. Londe S, Johanson A, Kronemer NS, and Goldring D: Blood pressure and puberty~ J PEDzATR87:896, 1975. 3. MOSSAJ, and Adams FH: Index of indirect estimation of diastolic blood pressure, Am J Dis Child 106:364, 1963. 4. Shock NW: Basal blood pressure and pulse rate in adolescents, Am J Dis Child 68:16, 1944. 5. Londe S, Bourgoignie JJ, Robson AM, and Goldring D: Hypertension in apparentIy normal children, J PEmATR 78:569, 1971. 6. Levy RL, et al: Transient hypertension: Its significance in terms of later development of sustained hypertension and cardiovascular renal disease, JAMA 126:829, 1944.
