Scientific Contributions Isolated Systolic Hypertension Prognostic Information Provided by Pulse Pressure
Michael J. Domanski, Barry R. Davis, Marc A. Pfeffer, Mark Kastantin, Gary F. Mitchell
Abstract—Increased arterial stiffness results in increased characteristic impedance of the aorta and increased pulse wave
velocity, which increases systolic and pulse pressures. An association between increased pulse pressure and adverse cardiovascular events has been found in normotensive and hypertensive patient populations. Increased pulse pressure has also been associated with thickening of the carotid intima and media. However, the relationship between pulse pressure and stroke has not previously been evaluated. In this study, we examined the hypothesis that pulse pressure is an independent predictor of stroke in elderly patients with systolic hypertension entered in the Systolic Hypertension in the Elderly Program. Differences in baseline characteristics were examined by tertiles of pulse pressure. The independent prognostic value of pulse pressure and mean arterial pressure for predicting either stroke or total mortality was assessed with Cox proportional hazards models that included pulse pressure, mean arterial pressure, and other variables that were significant on univariate analysis. This analysis demonstrated an 11% increase in stroke risk and a 16% increase in risk of all-cause mortality for each 10-mm Hg increase in pulse pressure. Each 10-mm Hg increase in mean arterial pressure was independently associated with a 20% increase in the risk of stroke and a 14% increase in the risk of all-cause mortality. These data provide strong evidence of an association of increased conduit vessel stiffness, as indicated by increased pulse pressure, with stroke and total mortality, independent of the effects of mean arterial pressure, in elderly patients with isolated systolic hypertension. (Hypertension. 1999;34:375-380.) Key Words: pulse pressure Ⅲ stroke Ⅲ hypertension Ⅲ elderly Ⅲ compliance
The association between hypertension, particularly systol- sure (SBP) and pulse pressure as well as a decrease in
ic hypertension, and cerebrovascular disease, including
diastolic blood pressure (DBP). In addition, the increased
carotid atherosclerosis and stroke, has been established.1
stiffness causes an increase in pulse wave velocity. A more
Once thought to be a benign accompaniment of aging,
rapid pulse wave velocity results in premature return of the
isolated systolic hypertension is now known to increase the
reflected pressure wave to the central aorta in systole rather
risk of stroke and other adverse cardiovascular events. Fur-
than diastole, which further increases the pulse pressure.
thermore, the Systolic Hypertension in the Elderly Program
Because of these relationships, pulse pressure has been used
(SHEP) clearly demonstrated that effective treatment of
as a crude index of aortic stiffness even though left ventric-
isolated systolic hypertension in elderly patients markedly
ular ejection rate and stroke volume may also influence pulse
reduced this risk of stroke.2 Evidence that implicates in-
creased conduit vessel stiffness and elevated pulse pressure as
An association between increased pulse pressure and
important correlates of the cerebrovascular pathophysiology
adverse cardiovascular events, presumably due to a detri-
of hypertension, especially isolated systolic hypertension, is
mental influence of increase in stiffness of the conduit
accruing.1,3–14 In a substudy of the SHEP population, in-
vessels, has been demonstrated in normotensive and hy-
creased pulse pressure was shown to be an independent
pertensive patient populations17–21 as well as in patients
predictor of carotid stenosis.5 That study provides a rationale
with reduced left ventricular function.15,16 This adverse
for an association between pulse pressure and the clinical end
association has been shown to be independent of age, mean
point of stroke in this patient population, although such an
arterial pressure (MAP), and other covariates thought to
influence pulse pressure or outcome in patients with
Increased conduit vessel stiffness results in increased
cardiovascular disease. Although a recent population-
characteristic impedance of the aorta and decreased arterial
based study speculated that increased pulse pressure may
compliance, which cause an increase in systolic blood pres-
help to explain the higher incidence of stroke in patients
Received February 4, 1999; first decision March 1, 1999; revision accepted April 14, 1999. From the Clinical Trials Group, National Heart, Lung, and Blood Institute, Bethesda, Md (M.J.D., M.K.); Brigham and Women’s Hospital, Harvard
Medical School, Boston, Mass (M.A.P.); University of Texas School of Public Health, Houston (B.R.D.); and Cardiovascular Engineering, Inc (G.F.M.),Dover, Mass.
Correspondence to Michael J. Domanski, MD, National Heart, Lung, and Blood Institute, 6701 Rockledge Dr, RM 8146, Bethesda, MD 20892-7936.
1999 American Heart Association, Inc. Hypertension is available at http://www.hypertensionaha.org 375 376 Hypertension September 1999 Baseline Characteristics by Pulse Pressure Tertile
with isolated systolic hypertension as opposed to those
population (Table 1). Evaluation by tertiles of pulse
with diastolic or mixed systolic/diastolic hypertension,3
pressure demonstrated an inverse association between
the direct relationship between pulse pressure and stroke
pulse pressure and MAP, indicating that higher pulse
has not been established. The present study examined the
pressure could not be attributed to an increase in distend-
association of pulse pressure and stroke as well as total
ing pressure alone. A higher pulse pressure was associated
mortality in patients randomized into SHEP.
with more advanced age, a higher proportion of women,greater frequency of previous use of antihypertensive
medication, history of diabetes, baseline ECG abnormali-
The SHEP trial was a randomized, controlled study of the effective-
ties, and lower prevalence of alcohol use. There were
ness of antihypertensive drug treatment in the prevention of stroke in
minimal trends toward lower body mass index and de-
4736 people with isolated systolic hypertension.2
Blood pressure readings at the first and second baseline visits were
creased prevalence of current smokers in patients with
averaged to establish a baseline blood pressure for each participant.
higher pulse pressure. Among the female patients, higher
Treatment goals were established on the basis of this baseline blood
pulse pressure was also associated with less frequent
pressure as previously described in detail.2 Initial therapy was
chlorthalidone, which was followed by atenolol or reserpine asneeded. Pulse pressure was calculated as the difference between
Univariate analysis was used to assess the impact of a
baseline and prerandomization SBP and DBP. MAP was calculated
variety of baseline variables on stroke (nϭ262) and total
according to the formula MAPϭ(2ϫDBPϩSBP)/3. Fatal or nonfatal
mortality (nϭ455). The effects of pulse pressure and MAP
stroke, according to previously described criteria,2 was the primary
on stroke, the primary end point of SHEP, were evaluated
with a Cox proportional hazards model that adjusted for
Statistical Methods
significant univariate predictors of stroke (Table 2). In this
Differences in baseline characteristics by tertile of pulse pressure
multivariate analysis, for each 10-mm Hg increase in pulse
were evaluated by ANOVA for continuous variables and by a test
pressure, there was an 11% (95% confidence interval, 1%
for linear trends for categorical variables. Baseline variables,
to 22%) increase in the risk of stroke (Table 2). Further-
including randomization assignment, age, pulse pressure, MAP,
more, for each 10-mm Hg increase in MAP, there was an
SBP, DBP, heart rate, race, gender, body mass index, educationalattainment, serum uric acid, HDL cholesterol, hematocrit, current
independent 20% increase in the risk of stroke, confirming
smoking status, history of intermittent claudication, presence of
the additive prognostic effects of the mean and pulsatile
carotid bruits, history of cardiovascular disease, presence of ECG
components of blood pressure on the risk of stroke.
abnormality, presence of left ventricular hypertrophy by ECG
To determine whether pulse pressure and MAP provide
criteria, history of stroke, history of diabetes, alcohol consump-
independent prognostic information concerning the risk of
tion Ն1 drink per week, and history of myocardial infarction,were evaluated as predictors of stroke and total mortality with a
death in this population, a Cox proportional hazards model
Cox proportional hazards model. All univariate predictors asso-
was constructed that included these variables as well as
ciated with an end point (PϽ0.10) were included in a preliminary
variables that were significant predictors of all-cause
multivariate analysis. Those that remained significant (PϽ0.10)
mortality on univariate analysis. In this mortality analysis,
were included in the final models along with pulse pressure andMAP.
pulse pressure was again independently predictive of totalmortality (Table 2). For each 10-mm Hg increase in pulse
pressure, there was a 16% (95% confidence interval, 8% to
Higher pulse pressure was associated with both an increase
24%) increase in the risk of death. MAP was also predic-
in SBP as well as a decrease in DBP in this elderly patient
tive of increased mortality. For each 10-mm Hg increase in
Domanski et al Pulse Pressure in Systolic Hypertension 377 Risk Ratios for Factors Examined
HDL cholesterol (per 0.39-mmol/L increase)
MAP, there was a 14% increase in the risk of total
conduit vessels. However, the selection criteria for SHEP,
increased SBP with normal or low DBP, effectivelyeliminated patients whose pulse pressure was elevated
Discussion
solely as a result of increased MAP. Consequently, the
This analysis demonstrates that MAP and pulse pressure,
relationship between MAP and pulse pressure was inverted
calculated with data derived from sphygmomanometry, are
in SHEP patients, with increasing tertiles of pulse pressure
independent predictors of stroke and all-cause mortality.
associated with lower levels of MAP. Therefore, increased
The usefulness of a physiological interpretation of blood
pulse pressure in this patient population was not simply
pressure in terms of both its pulsatile (pulse pressure) and
secondary to, or a surrogate for, elevated MAP but rather
nonpulsatile (MAP) components is emphasized by the
was more likely an indicator of a primary increase in
results of this analysis. The well-characterized population
of patients in SHEP permitted quantitative estimates of theprognostic implications of pulse pressure and MAP by use
Physiological Considerations
of an analysis that adjusts for a large number of potentially
With aging and repetitive cyclical stress, there is a break-
confounding covariates. Each 10-mm Hg increase in pulse
down of the elastin in the walls of conduit vessels, which
pressure resulted in an 11% increase in the risk of stroke
leads to reduced compliance of the vessel.22 This process
and a 16% increase in the risk of death independent of
appears to be accelerated by diseases such as diabetes23
other covariates, including MAP. MAP was also indepen-
and hypertension24,25 as well as by dietary factors, includ-
dently associated with risk of adverse cardiovascular
ing high salt intake,25,26 and menopause.27 Heart failure is
events, with a 20% increase in the risk of stroke and a 14%
also associated with increased conduit vessel stiffness,
increase in the risk of death associated with each 10-
possibly because of the effect of neurohumoral activa-
mm Hg rise in MAP. SBP is also an important predictor of
tion.28 Stiffening results in increased aortic impedance and
stroke and mortality in this population. On the other hand,
an increase in pulse wave velocity. The increase in
in the Studies of Left Ventricular Dysfunction (SOLVD),15
impedance causes a larger pulsatile pressure wave for a
SBP was not a significant predictor of mortality. DBP was
given pulsatile flow. Increased pulse wave velocity causes
significantly, although inversely, associated. In the Sur-vival and Ventricular Enlargement (SAVE) trial, both SBP
premature return of the pulse wave reflection from the
and DBP were significantly associated with survival.16 In
periphery. The reflected wave, therefore, arrives in the
each of these studies, pulse pressure was predictive. This
central aorta during systole rather than diastole, further
emphasizes the utility of the use of pulse pressure to
increasing central SBP and pulse pressure. This late
integrate the effects of both SBP and DBP and its physi-
augmentation of SBP progressively reduces, and ulti-
ological importance as a measure of conduit vessel
mately eliminates, the normal augmentation of the pressure
waveform that occurs as the pressure wave travels from the
Of interest is the relationship between pulse pressure
central aorta to peripheral arteries, such as the brachial
and MAP across the tertiles of pulse pressure in SHEP.
artery, where blood pressure is usually evaluated. Thus, the
Because large conduit vessels are nonlinearly elastic, an
increase in pulse pressure in the brachial artery is indica-
increase in MAP could lead to an increase in conduit vessel
tive of, but systematically and substantially underesti-
stiffness, which could lead to an increase in pulse pressure,
mates, the increase in central aortic pulse pressure with
regardless of the intrinsic stiffness or composition of the
advancing age and increasing conduit vessel stiffness. 378 Hypertension September 1999
Increased central aortic pulse pressure may play an
confounding covariates. We recently studied the prognostic
important role in the pathogenesis and manifestation of
importance of pulse pressure in patients with left ventricular
carotid and coronary atherosclerosis rather than simply
dysfunction entered in the SOLVD trial.16 In this population
serving as a marker of the presence of disease. Increased
with left ventricular dysfunction and heart failure, pulse
pulse pressure has been shown to promote the development
pressure was again associated with increased mortality. In
of atherosclerosis in a primate model29 and may increase
contrast, in this heart failure–left ventricular dysfunction
the likelihood of plaque rupture as a result of the fatiguing
population, MAP was inversely correlated with increased risk
effects of pulsatile strain.30 Several studies have docu-
of death, further emphasizing the independent nature of
mented the independent association between pulse pres-
changes in MAP and pulse pressure and their effects on
sure and measures of carotid artery disease, including
intima-media thickness and plaque area.5–10,12–14 Pulse
The studies discussed have examined patients across a
pressure has also been related to small-vessel disease in the
wide range of left ventricular function, from low in SOLVD
cerebral circulation in animal models.31,32 Furthermore,
to intermediate in SAVE to normal in SHEP. Together, they
resolution of small-vessel remodeling in those studies was
support the importance of aortic stiffening as an independent
more closely related to changes in pulse pressure than to
risk factor for adverse cardiovascular events. They raise the
changes in MAP. Increased prevalence and severity of
question of whether interventions that reduce conduit vessel
white matter lesions, which are thought to be related to
stiffness will have improved efficacy with respect to cardio-
small-vessel disease, was associated with increased pulse
vascular end points. Also, they emphasize the need for a more
pressure in 1920 men and women 55 to 72 years of age
direct measure of aortic stiffness, particularly if studies of the
who were evaluated by magnetic resonance imaging as part
therapeutic effectiveness of reducing aortic stiffness are
of the Atherosclerosis Risk in Communities (ARIC)
This is the first analysis to evaluate the direct effects of
Clinical Implications
pulse pressure as a risk factor for a cerebrovascular
The observation that increased pulse pressure is associated
accident. Prior reports from the Framingham Heart Study1
with a higher risk of stroke and total mortality becomes
and more recently from the Copenhagen City Heart Study3
particularly relevant as therapeutic options are shown to
were consistent with a role of pulse pressure as a predictor
have a differential effect on conduit vessel stiffness. This
of stroke. Both studies found that SBP was superior to
differential effect may translate into improved efficacy
DBP as a determinant of stroke risk; however, neither
with agents that preferentially reduce conduit vessel stiff-
evaluated the quantitative effect of pulse pressure. Further-
ness. Furthermore, such therapy may be preferentially
more, the Framingham analysis established the connection
targeted to patients with documented elevations of pulse
between increased SBP and conduit vessel stiffness by
pressure or conduit vessel stiffness. There is evidence that
assessing an oscillometric finger-pulse tracing. They found
currently available therapeutic interventions may be able
that an abnormal pulse waveform, indicative of premature
to modify conduit vessel stiffness. Lifestyle interventions,
arrival of the reflected wave, was associated with an
such as lower sodium intake33 and increased exercise,34,35
increased prevalence of isolated systolic hypertension.
are associated with improved aortic compliance. Convert-
Additional studies have suggested the importance of pulse
ing enzyme inhibitors have a highly favorable effect on
pressure as an independent prognostic indicator for other
conduit vessels.36 Low-dose diuretics effectively reduce
cardiovascular end points, including myocardial infarction
conduit vessel stiffness37 and pulse pressure38,39 in elderly
and death.15–21 The effects of SBP, DBP, and pulse pressure
patients. In contrast, -blockers, as monotherapy, have
were studied in the Hypertension Detection and Follow-up
been shown to increase conduit vessel stiffness and the
Program.21 In patients who were untreated at baseline, pulse
magnitude of the reflected wave.40,41 Results with calcium
pressure was a significant predictor of total mortality. In a
channel blockers have been mixed.42– 44 Additional long-
multivariate analysis, Madhaven et al19 found that increased
term studies with direct, repeated measurements of conduit
pulse pressure was an independent predictor of myocardial
vessel stiffness are needed to further refine the role of
infarction in a 5-year follow-up study of hypertensive indi-
therapy targeted to reducing conduit vessel stiffness.
viduals. In a large sample of a general population, Darne et
Another important clinical implication is that by use of
al,17 and later Benetos et al18 in a follow-up analysis, found
only SBP or DBP for study inclusion criteria and thera-
that increased pulse pressure was associated with adverse
peutic decisions, trialists and clinicians may be underesti-
cardiovascular events, independent of MAP and other cardiac
mating risk in patients with moderately increased SBP and
The relationship between pulse pressure and adverse
events was evaluated in the Survival and Ventricular Enlarge-
Limitations
ment trial.15 Patients entered in the trial had recently had a
Pulse pressure is an imperfect measure of vascular com-
myocardial infarction and a left ventricular ejection fraction
pliance. It seems unlikely, however, that other potential
Յ0.40. Despite the reduction in ejection fraction, pulse
determinants of increased pulse pressure, such as increased
pressure emerged as a strong independent predictor of both
peak ejection rate or stroke volume, would be associated
total mortality and recurrent myocardial infarction in multi-
with an adverse prognosis. Nonetheless, it is clear that
variate analyses that adjusted for a number of potentially
more direct measures of conduit vessel stiffness would be
Domanski et al Pulse Pressure in Systolic Hypertension 379
useful in future studies. This analysis was exploratory in
15. Mitchell G, Moye L, Braunwald E, Rouleau J, Bernstein V, Geltman
nature, because an analysis of the association of pulse
E, Flaker G, Pfeffer M, for the SAVE Investigators. Sphygmomano-metrically determined pulse pressure is a powerful independent pre-
pressure with adverse events (stroke and death) was not a
dictor of recurrent events after myocardial infarction in patients with
prespecified end point of SHEP. The findings of this
impaired left ventricular function. Circulation. 1997;96:4254 – 4260.
analysis apply to elderly patients with isolated systolic
16. Domanski MJ, Mitchell GF, Norman J, Pitt B, Exener D, Pfeffer MA.
hypertension, specifically the population randomized into
Independent prognostic information provided by sphygmomano-metrically determined pulse pressure and mean arterial pressure in
SHEP. However, the prognostic importance of pulse pres-
patients with left ventricular dysfunction. J Am Coll Cardiol. 1999;33:
sure on total mortality has now been demonstrated across
a wide range of patient populations.
17. Darne B, Girerd X, Safar M, Cambien F, Guize L. Pulsatile versus
steady component of blood pressure: a cross-sectional analysis and a
Conclusions
prospective analysis on cardiovascular mortality. Hypertension. 1989;13:392– 400.
This study provides strong evidence of an association of
18. Benetos A, Safar M, Rudnichi A, Smulyan H, Richard J-L, Ducimetiere
increased conduit vessel stiffness, as indicated by increased
P, Guize L. Pulse pressure: a predictor of long-term cardiovascular
pulse pressure, with stroke and total mortality in elderly
mortality in a French male population. Hypertension. 1997;30:
patients with isolated systolic hypertension. More study is
19. Madhavan S, Ooi WL, Cohen H, Alderman MH. Relation of pulse
needed to determine whether therapeutic interventions that
pressure and blood pressure reduction to the incidence of myocardial
preferentially alter conduit vessel stiffness can more favor-
infarction. Hypertension. 1994;23:395– 401.
ably alter stroke and mortality rates.
20. Fang J, Madhavan S, Cohen H, Alderman MH. Measures of blood
pressure and myocardial infarction in treated hypertensive patients. J Hypertens. 1995;13:413– 419. References
21. Abernethy J, Borhani NO, Hawkins CM, Crow R, Entwisle G, Jones JW,
1. Kannel WB, Wolf PA, McGee DL, Dawber TR, McNamara P, Castelli
Maxwell, MH, Langford H, Pressel S. Systolic blood pressure as an
WP. Systolic blood pressure, arterial rigidity, and risk of stroke: the
independent predictor of mortality in the Hypertension Detection and
Framingham study. JAMA. 1981;245:1225–1229.
Follow-Up Program. Am J Prev Med. 1986;2:123–132.
2. SHEP Cooperative Research Group. Prevention of stroke by antihyper-
22. Nichols WW, O’Rourke MF. “Aging” in McDonald’s Blood Flow in
tensive drug treatment in older persons with isolated systolic hyper-
Arteries: Theoretical, Experimental and Clinical Principles. 4th ed.
tension: final results of the Systolic Hypertension in the Elderly Program
(SHEP). JAMA. 1991;65:3255–3264.
23. Salomaa V, Riley W, Kark JD, Nardo C, Folsom AR. Non-insulin-
3. Nielsen WB, Lindenstrom E, Vestbo J, Jensen GB. Is diastolic hyper-
dependent diabetes mellitus and fasting glucose and insulin concen-
tension an independent risk factor for stroke in the presence of normal
trations are associated with arterial stiffness indexes: the ARIC study.
systolic blood pressure in the middle-aged and elderly? Am J Hypertens. Circulation. 1995;91:1432–1443.
24. Nichols WW, O’Rourke MF, Avolio AP, Yaginuma T, Pepine CJ,
4. Sutton-Tyrrell K, Alcorn HG, Wolfson SK Jr, Kelsey SF, Kuller LH.
Conti R. Ventricular/vascular interaction in patients with mild
Predictors of carotid stenosis in older adults with and without isolated
systemic hypertension and normal peripheral resistance. Circulation.
systolic hypertension. Stroke. 1993;24:355–361.
5. Franklin SS, Sutton-Tyrrell K, Belle SH, Weber MA, Kuller LH. The
25. Avolio AP, Deng FQ, Li WQ, Luo YF, Huang ZD, Xing LF, O’Rourke
importance of pulsatile components of hypertension in predicting carotid
MF. Effects of aging on arterial distensibility in populations with high and
stenosis in older adults. J Hypertens. 1997;15:1143–1150.
low prevalence of hypertension: comparison between urban and rural
6. Suurkula M, Agewall S, Fagerberg B, Wendelhag I, Widgren B,
communities in China. Circulation. 1985;71:202–210.
Wikstrand J, for the Risk Intervention Study Group. Ultrasound eval-
26. Avolio AP, Clyde KM, Beard TC, Cooke HM, Ho KKL, O’Rourke MF.
uation of atherosclerotic manifestations in the carotid artery in
Improved arterial distensibility in normotensive subjects on a low salt
high-risk hypertensive patients. Arterioscler Thromb. 1994;14:
diet. Arteriosclerosis. 1986;6:166 –169.
27. Glasser S, Arnett D, McVeigh G, Finklelstein S, Bank A, Morgan D,
7. Witteman JCM, Grobbee DE, Valkenburg HA, van Hemert AM, Stijnen
Cohn J. Vascular compliance and cardiovascular disease: a risk factor or
T, Burger H, Hofman A. J-shaped relation between change in diastolic
a marker? Am J Hypertens. 1997;10:1175–1189.
blood pressure and progression of aortic atherosclerosis. Lancet. 1994;
28. Arnold J, Marchiori G, Imrie J, Burton G, Pflugfelder P, Kostuk W.
Large artery function in patients with chronic heart failure: studies of
8. Lassila HC, Tyrrell KS, Matthews KA, Wolfson SK, Kuller LH. Prev-
brachial artery diameter and hemodynamics. Circulation. 1991;84:
alence and determinants of carotid atherosclerosis in healthy postmeno-pausal women. Stroke. 1997;3:513–517.
9. Matthews KA, Owens JF, Kuller LH, Sutton-Tyrrell K, Lassila HC,
29. Lyon RT, Runyon-Hass A, Davis HR, Glagov S, Zarins CK. Protection
Wolfson SK. Stress-induced pulse pressure change predicts women’s
from atherosclerotic lesion formation by reduction of artery wall motion.
carotid atherosclerosis. Stroke. 1998;29:1525–1530. J Vasc Surg. 1987;5:59 – 67.
10. Salonen R, Salonen JT. Determinants of carotid intima-media thickness:
30. Cheng GC, Loree HM, Kamm RD, Fishbein MC, Lee RT. Distribution of
a population-based ultrasonography study in eastern Finnish men. J Intern
circumferential stress in ruptured and stable atherosclerotic lesions: a
structural analysis with histopathological correlation. Circulation. 1993;
11. Liao D, Cooper L, Cai J, Toole J, Bryan N, Burke G, Shahar E, Nieto
J, Mosley T, Heiss G. The prevalence and severity of white matter
31. Baumbach GL, Siems JE, Heistad DD. Effects of local reduction in
lesions, their relationship with age, ethnicity, gender, and cardiovas-
pressure on distensibility and composition of cerebral arterioles. Circ Res.
cular disease risk factors: the ARIC study. Neuroepidemiology. 1997;
32. Heistad DD, Armstrong ML, Baumbach GL, Faraci FM. Sick vessel
12. Bots ML, Witteman JCM, Hofman A, de Jong PTVM, Grobbee DE. Low
syndrome: recovery of atherosclerotic and hypertensive vessels. Hyper-
diastolic blood pressure and atherosclerosis in elderly subjects: the
Rotterdam study. Arch Intern Med. 1996;156:843– 848.
33. Avolio AP, Clyde KM, Beard TC, Cooke HM, Ho KKL, O’Rourke MF.
13. Khattar RS, Acharya DU, Kinsey C, Senior R, Lahiri A. Longitudinal
Improved arterial distensibility in normotensive subjects on a low salt
association of ambulatory pulse pressure with left ventricular mass and
diet. Arteriosclerosis. 1986;6:166 –169.
vascular hypertrophy in essential hypertension. J Hypertens. 1997;15:
34. Vaitkevicius P, Fleg J, Engel J, O’Conner F, Wright J, Lakatta L, Yin F,
Lakatta E. Effects of age and aerobic capacity on arterial stiffness in
14. Bots ML, Hofman A, Grobbee DE. Increased common carotid intima-
healthy adults. Circulation. 1993;88:1456 –1462.
medial thickness: adaptive response or a reflection of atherosclerosis?
35. Cameron J, Dart A. Exercise training increases total systemic arterial
Findings from the Rotterdam study. Stroke. 1997;28:2442–2447.
compliance in humans. Am J Physiol. 1994;266:H693–H701. 380 Hypertension September 1999
36. Safar M, van Bortel L, Struijker-Boudier H. Resistance and conduit
40. Ting C, Chen C, Chang M, Yin F. Short- and long-term effects of
arteries following converting enzyme inhibition in hypertension. J Vasc
antihypertensive drugs on arterial reflections, compliance, and
impedance. Hypertension. 1995;26:524 –530.
37. Girerd X, Giannattasio C, Moulin C, Safar M, Mancia G, Laurent S.
41. De Cesaris R, Ranieri G, Filitti V, Andriani A. Large artery compliance
Regression of radial arterial wall hypertrophy and improvement of carotid
in essential hypertension: effects of calcium antagonism and beta-
artery compliance after long-term antihypertensive treatment in elderly
blocking. Am J Hypertens. 1992;5:624 – 628.
patients. J Am Coll Cardiol. 1998;31:1064 –1073.
42. Herpin D, Ragot S, Vaisse B, Ferrandis J, Baguet J, Mallion J, Poggi L.
38. Ekbom T, Dahlof B, Hansson L, Lindholm L, Schersten B, Webster P.
Drug-induced changes in ambulatory blood pressure and pulse pressure in
Antihypertensive efficacy and side effects of three beta-blockers and a
patients with or without sustained hypertension. Therapie. 1996;51:
diuretic in elderly hypertensives: a report from the STOP-Hypertension
study. J Hypertens. 1992;10:1525–1530.
43. Pannier B, Lafleche A, Girerd X, London G, Safar M. Arterial stiffness
39. Heesen W, Beltman F, Smit A, May J, de Graeff P, Havinga T,
and wave reflections following acute calcium blockade in essential hyper-
Schuurman F, van der Veur E, Mayboom-de Jong B, Lie K. Effect of
tension. Am J Hypertens. 1994;7:168 –176.
quinapril an triamterene/hydrochlorothiazide on cardiac and vascular
44. Shimamoto H, Shimamoto Y. Lisinopril reverses left ventricular hyper-
end-organ damage in isolated systolic hypertension. J Cardiovasc
trophy through improved aortic compliance. Hypertension. 1996;28:
Pharmacol. 1998;31:187–194.
Interlayer structures and binding Carbonate ooid formation in a conformations in the interaction of a modern freshwater lake: tetracycline antibiotic with a smectite How determinant is the biological role? Section of Earth and Environmental Sciences, University of 1Environmental Geochemistry Group, LGIT, Grenoble, France Geneva, 13 rues des Maraichers, 1205 Geneva,
ATHLETICS OMNIBUS – DIFFERENCES BETWEEN MEN AND WOMEN From the Athletics Omnibus of Richard Stander, South Africa 1. INTRODUCTION Throughout history perceptions existed that men are superior to women. The development of women was, and in some cases still are, suppressed by cultural and religious believes. Prejudice in many cases made the development of female athletics difficul