(Circulation. 1995;91:734-740.)
© 1995 American Heart Association, Inc.
Articles |
Determinants of Echocardiographic Aortic Root Size
The Framingham Heart Study
From the Framingham Heart Study, Framingham, Mass (R.S.V., M.G.L., D.L.); the Divisions of Cardiology and Clinical Epidemiology, Beth Israel Hospital, Boston, Mass (D.L.); Boston (Mass) University School of Medicine (R.S.V., M.G.L., D.L.); and the National Heart, Lung, and Blood Institute, Bethesda, Md (D.L.).
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Abstract |
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Background Previous studies that evaluated the determinants of aortic root size have not yielded uniform results. We examined the relations of age, height, weight, body surface area, sex, and blood pressure to echocardiographically determined aortic root size in a population-based cohort.
Methods and Results The study sample consisted of 1849 men and 2152 women in the Framingham Heart Study and Framingham Offspring Study who were free of clinically apparent cardiac disease when echocardiography was performed. Aortic root measurements were made by M-mode echocardiography using a leading-edge-to-leading-edge technique. The relations of age, height, weight, body surface area, and blood pressure variables (contemporary and those obtained 8 years before) to aortic root dimension were examined by use of sex-specific correlations and linear regression analyses. Age, height, weight, and sex emerged as the principal determinants of aortic root dimensions in adults (cumulative R2=.2085 in men and .2327 in women). The additional effect of contemporary or previous blood pressure measures was small and revealed direct associations of aortic root dimension with mean arterial and diastolic blood pressures and inverse associations with pulse and systolic blood pressures. Previous blood pressure measurements did not contribute significantly to prediction of aortic root size once contemporary blood pressure variables entered the models. Results of regression analyses using a sex-pooled data set showed that on average, the aortic root measurement in women was 2.4 mm smaller than that of men of comparable age, height, and weight. Logistic regression was used to assess the likelihood of aortic root enlargement according to blood pressure levels. After adjustment for age, height, and weight, the odds ratio of aortic dilation for a 1-SD increment in systolic pressure was 0.70 (95% CI, 0.52 to 0.95) in men and 0.79 (95% CI, 0.60 to 1.04) in women; the odds ratio for a 1-SD increment in diastolic pressure was 1.22 (95% CI, 0.91 to 1.63) in men and 1.33 (95% CI, 1.01 to 1.73) in women.
Conclusions Age, height, weight, and sex emerged as the principal determinants of aortic root dimensions. The additional influences of blood pressure measurements were small; direct associations of aortic root dimensions with mean arterial and diastolic blood pressures and inverse associations with pulse and systolic blood pressures were observed. Additional prospective studies are needed to confirm these observations and to assess the impact of aortic root dimensions on the incidence of hypertension.
Key Words: aorta • echocardiography • blood pressure
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Introduction |
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TopAbstractIntroductionMethods Results Discussion References |
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Age-related dilation of the aortic root is the most common cause of aortic regurgitation in developed countries.1 2 3 4 The prevalence of aortic regurgitation increases linearly with an increase in aortic root size.5 Aortic root size is also of prognostic importance in subjects with idiopathic annuloaortic ectasia and Marfan's syndrome.6 7 Therefore, the study of the normal biological determinants of aortic root size is important.
The biological variables recognized to influence aortic root size include age, sex, indexes of body size, systolic and diastolic blood pressures, and stroke volume.8 9 10 Studies that evaluated the determinants of aortic root size, however, have not yielded uniform results. These previous studies were not population-based, and the numbers of subjects were small. No prior study included a sufficient number of subjects beyond the seventh decade of life, at which time age-related changes in the structural and functional properties of the thoracic aorta become more pronounced.11
In the present study, we examined the relations of age, height, weight, body surface area (BSA), sex, contemporary and long-term blood pressures (systolic, diastolic, mean), and pulse pressure to echocardiographically determined aortic root size in subjects from the Framingham Heart Study.
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Methods |
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TopAbstractIntroductionMethods Results Discussion References |
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Study Sample
The selection criteria and study designs of the Framingham Heart Study and the Framingham Offspring Study have been detailed extensively.12 13 Subjects of the Framingham Heart Study who participated in the 16th biennial examination (1979-1981) and subjects of the Framingham Offspring Study who participated in the second offspring examination (1979-1983) constituted the study sample used in this investigation. At these index examinations, M-mode echocardiograms were uniformly performed on participating subjects. Subjects were excluded if they fulfilled any of the following criteria, in hierarchical order: (1) clinically apparent aortic or mitral valvular disease identified by the presence of a diastolic or systolic murmur (grade 3/6 or more) on precordial auscultation (n=245); (2) clinically apparent coronary heart disease, congestive heart failure, or atrial fibrillation at or before the index examination (n=553); (3) use of cardiovascular medications at the index examination (n=1081); (4) age <20 or
90 years (n=12); (5) morbid obesity defined as
body
mass index (BMI) >35 (n=119); (6) missing or unobtained blood
pressure
information (n=49); and (7) unavailable or technically inadequate
echocardiograms at the index examination (n=154).
Methods of Measurement and Definitions
Blood pressure data
were made up of two measurements of systolic
and diastolic pressures determined by the first and fifth Korotkoff
sounds, respectively, in the left arm of the seated subject obtained by
a physician using a mercury column sphygmomanometer. The following
definitions of blood pressure variables were used: (1) index systolic
blood pressure was the mean of the two systolic pressure readings
obtained at the index examination when the echocardiogram was obtained;
(2) index diastolic blood pressure was the mean of two diastolic
pressure readings obtained at the index examination; (3) index pulse
pressure was the difference between the index systolic and diastolic
blood pressures; (4) index mean arterial pressure was the sum of the
index diastolic blood pressure plus one third of the index pulse
pressure; and (5) previous blood pressures were the corresponding blood
pressure variables obtained at a clinic examination 8 years before the
index examination.
Body height and weight measurements obtained at the index examination were used to calculate BMI (weight in kilograms divided by the square of height in meters). BSA was calculated with the Du Bois14 formula.
All subjects underwent M-mode echocardiograms. More than 90% of the M-mode studies were obtained with two-dimensional (2D) echocardiographic guidance.15 All studies were performed with a 2.25 MHz, 1.25-cm diameter, unfocused transducer (K.B. Aerotech) and a Hoffrel 201 ultrasound receiver (Hoffrel Instruments) interfaced with a Honeywell 1856 strip chart recorder. Aortic root size was measured from the M-mode tracings in accordance with the American Society of Echocardiography (ASE) guidelines using a leading edge to leading edge measurement of the maximal distance between the anterior aortic root wall and the posterior aortic root wall at end diastole.16
Statistical Methods
All analyses were sex-specific. The
relations of age, height,
weight, BSA, stroke volume, and blood pressure (predictor variables) to
aortic root dimension (dependent variable) were initially examined
through calculation of simple and partial correlation
coefficients.17 Multiple linear regression analyses were
used to evaluate the relative influences of these predictor variables
on aortic root dimensions.17 Logistic
regression18 was used to assess the likelihood of aortic
root enlargement (defined as a value exceeding the 95th percentile
value) according to blood pressure variables, with adjustment for age
and anthropometric measures. A two-sided significance level of .05 was
used for each statistical test. All statistical analyses were performed
with the STATISTICAL ANALYSIS SYSTEM (SAS)19
on a SUN sparc 2 workstation.
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Results |
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TopAbstractIntroductionMethods Results Discussion References |
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Study Sample
Of the 2803 men and 3411 women who attended the index examinations, 1849 men (66%) and 2152 women (63%) ranging in age from 20 to 89 years were eligible for analysis after exclusions. Table 1
lists the clinical and echocardiographic
characteristics of the subjects. Mean aortic root size was larger in
men than in women. Indexing for height or BMI resulted in a larger mean
aortic root size in men; indexing for BSA or weight resulted in a
higher value in women.
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Simple and Partial Correlation Analyses
Table
2 gives the results of sex-specific
correlations. These analyses revealed highly significant but modest
correlations of each of the predictor variables with aortic root size,
except for height in women. After adjustment for age, all
anthropometric and blood pressure variables (other than systolic blood
pressure) remained significantly related to aortic root size.
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Stepwise Linear Regression
Effects of Anthropometric
Measures on Aortic Root Dimensions
Linear regression models were
initiated with the inclusion of age
and anthropometric predictor variables. Models with (1) age, (2)
height, and (3) weight, BMI, or BSA were studied. When squares of these
variables were added to the models, only height squared in men was
statistically significant, but its contribution to the model was
negligible (the increment in R2 was .0017,
P=.046). To create a simple, parsimonious model, squared
terms of anthropometric measures were avoided. Table 3
lists the regression coefficients and the standard errors of the basic
regression model that included age, height, and weight.
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Effects of Blood Pressure Variables
The blood
pressure variables were then added to the basic model in
a forward stepwise fashion. Both systolic and diastolic blood pressures
were entered into the model, and both were highly significant
(P<.0001). Addition of previous blood pressure terms
(variables from 8 years before) indicated that previous diastolic blood
pressures in men and women and previous systolic blood pressures in men
yielded statistically significant coefficients, but increments in
R2 were minimal. Age–blood pressure
interactions were examined; an age-related interaction term with
systolic blood pressure was significant but small in men (increment in
R2=.0036, P=.003) but not in women
(P>.40). There was no significant
age–diastolic blood pressure interaction. Because in
samples this large, statistical significance can be achieved with very
small effects, predictor variables relating to previous blood pressure
and interaction terms were eliminated to avoid overfitting.
Additional
regression models were considered with age, height,
weight, and (1) systolic blood pressure, (2) diastolic blood pressure,
(3) systolic and diastolic blood pressures, (4) mean arterial
pressure, and (5) pulse pressure. Table 4
lists the regression coefficients, R2,
and incremental R2 values for these models.
Although blood pressure variables did contribute to the prediction of
aortic root size, the changes in R2 from the
basic model (age, height, weight) were small. For instance, the
inclusion of both systolic and diastolic blood pressures increased the
R2 of the model by only .0115 in men and .0042
in women. The coefficients for diastolic blood pressure were slightly
higher than those for systolic blood pressure and were similar in
magnitude in men and women. When considered together, the mathematical
signs of regression coefficients for systolic and diastolic blood
pressures were opposite, suggesting a "pulse pressure effect."
Collinearity is an unlikely explanation for this observation because
the correlation between systolic and diastolic blood pressures was only
0.49.
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Figs 1 and 2 show observed data and
fitted regression lines for the equation
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based
on models 4 and 5 from Table 4
. Fig 1 indicates
that men and
women in the fourth quartile of mean arterial pressure have larger
predicted aortic root measurements than those in the first quartile.
Fig 2 shows that men and women in the first quartile of pulse
pressure
have larger aortic root measurements than subjects of the same sex in
the fourth quartile.
Sex-Related Differences
Although the primary analyses were
sex-specific, sex-related
interactions were explored in a sex-pooled data set. Results of these
analyses indicated that men and women have different aortic root
dimensions (holding all other variables equal and constant). On
average, the aortic root measurement in women was 2.4 mm smaller than
that of men of comparable age, height, and weight.
Aortic Root Dilatation
Multiple logistic regression was used
to determine the
contributions of blood pressure variables to the prevalence of aortic
root enlargement. Aortic root dilatation was defined as a value
exceeding the 95th percentile of the raw values of aortic root
dimensions. Logistic models were fitted that incorporated the
covariates of age, height, and weight. Blood pressure variables then
were entered in the following fashion: (1) contemporary systolic and
diastolic blood pressures, (2) contemporary mean arterial and pulse
pressures, (3) previous systolic and diastolic blood pressures, and (4)
contemporary and previous systolic and diastolic blood pressures. Table
5 gives the results. In general, contemporary and
previous systolic and diastolic blood pressures were significant
predictors of an enlarged aortic root in both sexes. After contemporary
blood pressure measurements were accounted for, previous measurements
of blood pressure did not contribute significantly. The regression
coefficients for systolic and diastolic blood pressures had opposite
mathematical signs: systolic blood pressure was inversely and diastolic
blood pressure was directly related to the probability of having an
enlarged aortic root measurement, suggesting a pulse pressure effect.
In both sexes, every 1-SD increment in pulse pressure was associated
with 25% lower odds of aortic root dilatation. When entered together
into the model, mean arterial pressure was directly related and pulse
pressure inversely related to the probability of having an enlarged
aortic root.
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Discussion |
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TopAbstractIntroductionMethods Results Discussion References |
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This study provides a systematic analysis of selected biological determinants of aortic root dimensions in an adult population-based cohort. Age, height, weight, and sex emerged as the principal determinants of aortic root dimensions. The additional influences of blood pressure measurements, although highly significant statistically, were small and revealed direct relations of aortic root dimensions with diastolic and mean arterial pressures and inverse relations with systolic and pulse pressures.
Effect of Anthropometric Variables
The relations of
anthropometric variables to aortic dimensions
have been recognized for a long
time20 21 22 and were
confirmed in more recent echocardiographic studies of the aortic
root.9 10 23 24 It has been
suggested that height is the
most important determinant of aortic root size compared with other
measurements such as BSA or weight.10 24 In the
present study, height and weight (and their derivatives, BSA and
BMI) predicted aortic root dimensions. Results of linear regression
analyses revealed that a 10-cm increment in height was associated with
0.24- (men) and 0.38-mm (women) increments in aortic root size.
Corresponding increments in aortic root dimensions for a 10-kg
increment in weight were 0.87 and 0.68 mm. The correlation of aortic
root dimension with anthropometric measures yielded smaller correlation
coefficients in our study compared with those reported in the
literature.9 10 24 Failure to account for
sex differences
in the previous studies may be an important reason for this difference
because sex-pooled analyses can inflate correlations if the
distributions of the variables differ in men and women.25
Pooling of children and adults in one study10 is another
reason for the inflation of previously reported correlation
coefficients because much of the variation of aortic root size among
children is related to body growth.
Effect of Age
Age-related dilation of the aortic root has
been consistently
reported in autopsy
series26 27 28 29 30 31
and in clinical studies
where chest roentgenograms, computed tomography, and magnetic resonance
imaging22 32 33 34 were used.
In contrast, clinical
echocardiographic studies have yielded disparate results. An
age-related increase was evident in some
studies9 23 35
but not in others.10 36 Some of these studies
included a
predominantly pediatric population10 ; none included a
sufficient number of subjects beyond the seventh decade, when the
age-related structural and functional changes in the aorta become more
apparent. In the present study, aortic root dimensions increased
gradually and smoothly with age in subjects of both sexes. Results of
the linear regression models (Table 3) revealed 0.8 (men) and
0.9 mm
(women) increases in aortic root dimension for each advancing decade of
age, after adjustment for height and weight. Such an age-related change
in vessel dimensions is seen in other vascular
territories37 38 39 40 and is
related to thinning and fracturing
of the elastic
laminae,11 41 42 43 44
presumably related to the
effects of cyclic stress.45 46 47 It has
been postulated that
because aortic distensibility declines with age, the aorta diameter
increases, so that the volume buffering capacity is
constant.39 48
Effect of Sex
While it is generally accepted that aortic root
dimensions are
smaller in women than in men,8 9 the basis for this
difference is not clear. Indexing for BSA has resulted in various
results; similar,9 larger,8 and
smaller29 values of indexed aortic root dimensions have
been reported in men compared with women. In the present study,
indexing the aortic root dimension produced variable results, depending
on the male/female ratio of the divisor selected for indexation.
Regression models that used a sex-pooled database indicated that women
on average have a 2.4 mm smaller aortic root dimension than men, even
after adjustment for anthropometric measures and age. Such sex-related
differences have also been observed in other vascular
territories.32 39 40
Effect of Blood Pressure Variables
Investigations of the
effects of systolic and diastolic pressures
on aortic root dimensions have produced inconsistent results. Direct
correlations with systolic24 and diastolic49
pressures and no significant correlations with either systolic or
diastolic pressure have been reported.9 Studies that
compared aortic root dimensions in hypertensive subjects with
normotensive age-matched control subjects have not found any consistent
difference.50 51 52
In the present
study, direct relations of aortic root size to
diastolic and mean arterial pressures were observed. The magnitude of
effect was very small after adjustment for the influence of age and
anthropometric measures. Interestingly, inverse relations of aortic
root diameter to systolic and pulse pressures were observed in the
present study. Results of linear regression models (Table 4)
revealed that a 10 mm Hg increment in pulse pressure was associated
with a 0.25 (men) and 0.09 mm (women) decrease in aortic root size
after adjustment for age and anthropometric measures. Although the
direction of these pressure relations may appear counterintuitive, such
an inverse relation between pulse pressure and the arterial lumen is
predicted by the equation for estimation of elastic modulus of the
aorta:
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where
R is the radius of the aorta, 
P is the pulse pressure,
and R is the change in radius of the artery.53 A
growing body of evidence suggests that in contrast to mean arterial
pressure, pulse pressure may have an important effect on alteration of
vascular structure in hypertensive
subjects.54 55 56 Similar
inverse relations of pulse pressure and arterial diameter have been
observed in other vascular territories57 and may be
related to pulse pressure–mediated intimomedial
hypertrophy58 59 or to reflex smooth muscle
activation in
the vessel wall, causing a decrease in vessel
diameter.60 61 In the present study, aortic
intimomedial thickness was not measured; we cannot exclude medial
hypertrophy as an explanation for the inverse relations of pulse
pressure and arterial diameter that we observed.
Although the findings of a direct relation of aortic root dimension to mean arterial pressure and an inverse relation to pulse pressure may seem paradoxical, they actually are consonant with normal physiology. This is because the hemodynamic determinants of mean arterial pressure and pulse pressure are different62 and these blood pressure variables have been shown to have differential effects on other physiological variables such as echocardiographic left ventricular mass.55 Further prospective studies are needed to confirm these observations.
Limitations
It has been stated that 2D echocardiography
offers advantages over
M-mode studies for the measurement of aortic root
dimensions.9 In the present study, M-mode measurements
of the aortic root were guided by 2D scanning, which increases the
quantitative reliability of the M-mode technique. However, only
standard left parasternal views were used to measure the aortic root
diameter. Ideally, high left parasternal, right parasternal, and other
modified views should be combined with the standard views for obtaining
the maximal aortic root diameter. Because these views are not routinely
performed in our laboratory, aortic root diameter may have been
underestimated in some patients. Interobserver and intraobserver
variabilities in the measurement of aortic root diameter were not
obtained in the present study; however, prior studies have
demonstrated the excellent reproducibility of M-mode echocardiographic
aortic root measurements.63
Because the ASE recommendations for measurement of aortic root diameter include the anterior wall of the aorta in the measure, the present study overestimates the true aortic root lumen. We have also assumed that blood pressure variables measured at the brachial artery are not substantially different from those at the aortic root. Whereas such an assumption is valid for mean arterial pressure (which remains the same throughout the vascular tree), pulse pressure is amplified at the level of the brachial artery because of earlier wave reflection,64 principally in younger subjects. We do not view this as a serious limitation of our study because other studies have demonstrated that aortic pulse pressure can be approximated to brachial pulse pressure in studies of central aortic distensibility.65
Conclusions
Aortic root dimension is highly dependent on age,
sex, and body
size measurements. The effect of blood pressure on aortic root
dimensions over and above these variables is small, with direct
associations with diastolic and mean blood pressures and inverse
associations with systolic and pulse pressures.
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Acknowledgments |
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Dr Vasan's research fellowship was made possible by a grant from Merck & Co Inc. Special thanks go to Sonya Vaziri, MD, for her assistance in compilation of the data set used in this manuscript and to Emelia Benjamin, MD, for her valuable comments on the manuscript.
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Footnotes |
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Reprint requests to Daniel Levy, MD, Framingham Heart Study, 5 Thurber St, Framingham, MA 01701.
Received May 31, 1994; accepted September 23, 1994.
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References |
|---|
|
TopAbstractIntroductionMethods Results Discussion References |
|---|
1. Davies MJ. Pathology of Cardiac Valves. Boston, Mass: Butterworth; 1980;37-61.
2. Olson LJ, Subramanian R, Edwards WD. Surgical pathology of pure aortic insufficiency: a study of 225 cases. Mayo Clin Proc. 1984;59:835-841. [Medline] [Order article via Infotrieve]
3. Roman MJ, Devereux RB, Niles NW, Hochreiter C, Kligfield P, Sato N, Spitzer MC, Borer JS. Aortic root dilatation as a cause of isolated, severe aortic regurgitation: prevalence, clinical and echocardiographic patterns, and relation to left ventricular hypertrophy and function. Ann Intern Med. 1987;106:800-807.
4. Michel PL, Acar J, Chomette G, Iung B. Degenerative aortic regurgitation. Eur Heart J. 1991;12:875-882.
5. Seder JD, Burke JF, Pauletto FJ. Prevalence of aortic regurgitation by color flow Doppler in relation to aortic root size. J Am Soc Echocardiogr. 1990;3:316-319. [Medline] [Order article via Infotrieve]
6. Fox R, Ren J, Pannidis IP, Kotler MN, Mintz GS, Ross J. Anuloaortic ectasia: a clinical and echocardiographic study. Am J Cardiol. 1984;54:177-181. [Medline] [Order article via Infotrieve]
7.
Brown OR, DeMots H, Kloster FE, Roberts A, Menashe VD, Beals
RK. Aortic root dilatation and mitral valve prolapse in Marfan's
syndrome: an echocardiographic study. Circulation. 1975;52:651-657.
8.
Francis GS, Hagan AD, Oury J, O'Rourke RA. Accuracy of
echocardiography for assessing aortic root diameter. Br Heart
J. 1975;37:376-378.
9. Roman MJ, Devereux RB, Kramer-Fox R, O'Loughlin J. Two-dimensional echocardiographic aortic root dimensions in normal children and adults. Am J Cardiol. 1989;64:507-512. [Medline] [Order article via Infotrieve]
10. Nidorf SM, Picard MH, Triulzi MO, Thomas JD, Newell J, King ME, Weyman AE. New perspectives in the assessment of cardiac chamber dimensions during development and adulthood. J Am Coll Cardiol. 1992;19:983-988. [Abstract]
11. Schlatman TJ, Becker AE. Histologic changes in the normal aging aorta: implication for dissecting aneurysms. Am J Cardiol. 1977;39:13-20. [Medline] [Order article via Infotrieve]
12. Dawber TR, Meadors GF, Moore FE. Epidemiologic approaches to heart disease: the Framingham Study. Am J Public Health. 1951;41:279-286.
13.
Kannel WB, Feinleib M, McNamara PM, Garrison RJ, Castelli WP.
An investigation of coronary heart disease in families: the Framingham
Offspring Study. Am J Epidemiol. 1979;110:281-290.
14. Du Bois D, Du Bois EF. Clinical calorimetry: X, a formula to estimate the approximate surface area if height and weight be known. Arch Intern Med. 1916;17:863-871.
15. Savage DD, Garrison RJ, Kannel WB, Anderson SJ, Feinleib M, Castelli WP. Considerations in the use of echocardiography in epidemiology: the Framingham Heart Study. Hypertension. 1987;9(suppl II):II-40-II-44.
16.
Sahn DJ, DeMaria A, Kisslo J, Weyman A. Recommendations
regarding quantitation in M-mode echocardiography: results of a survey
of echocardiographic measurements. Circulation. 1978;58:1072-1083.
17. Kleinbaum DG, Kupper LL, Muller KE. Applied Regression Analysis and Other Multivariable Methods. 2nd ed. Boston, Mass: PWS-Kent Publishing Co; 1988:718.
18. Hosmer DW, Lemeshow S. Applied Logistic Regression. New York, NY: John Wiley and Sons Inc; 1989:307.
19. SAS Institute Inc. SAS/STAT User's Guide Version 6. 4th ed. Cary, NC: SAS Institute Inc; 1989;2:chaps 27 and 36.
20. Kaufman L. Zur Frage der Aorta angusta: ein Beitrag zu den Normalmassen des Aortensystems. Veröff Geb Kriegs Konstitutionspathol. Jena: Gustav Fischer; 1919:2.
21. Hosselin HV. Ueber die Ursache der scheinbaren Abhängigkeit des Umsatzes von der Grösse der Körperüberfläche. Arch Anat Physiol. 1888;323-380.
22. Sheridan JT. The transverse diameter of the cardiac silhouette. Trans Assoc Life Ins Med Dir Am. 1941;28:49-73.
23.
Henry WL, Gardin JM, Ware JH. Echocardiographic measurements
in normal subjects from infancy to old age. Circulation. 1980;62:1054-1061.
24. Reed CM, Richey PA, Pulliam DA, Somes GW. Aortic dimensions in tall men and women. Am J Cardiol. 1993;71:608-610. [Medline] [Order article via Infotrieve]
25. Altman DG. Practical Statistics for Medical Research. London, UK: Chapman and Hall; 1991:318.
26. Silver MA, Roberts WC. Detailed anatomy of the normally functioning aortic valve in hearts of normal and increased weights. Am J Cardiol. 1985;55:454-461. [Medline] [Order article via Infotrieve]
27. Krovetz LJ. Age-related changes in size of the aortic valve annulus in man. Am Heart J. 1975;90:569-574. [Medline] [Order article via Infotrieve]
28. Waller BF, Roberts WC. Cardiovascular disease in the very elderly: analysis of 40 necropsy patients aged 90 years or over. Am J Cardiol. 1983;51:403-421. [Medline] [Order article via Infotrieve]
29. Kitzman DW, Scholz DG, Hagen PT, Ilstrup DM, Edwards WD. Age-related changes in normal human hearts during the first 10 decades of life, part II (maturity): a quantitative anatomic study of 765 specimens from subjects 20-99 years old. Mayo Clin Proc. 1988;63:137-146. [Medline] [Order article via Infotrieve]
30. Toda T, Tsuda N, Nishimori I, Leszczynski DE, Kummerow FA. Morphometrical analysis of the aging process in human arteries and aorta. Acta Anat (Basel). 1980;106:35-44. [Medline] [Order article via Infotrieve]
31. Virmani R, Avolio AP, Mergner WJ, Robinowitz M, Herderick EE, Cornhill JF, Guo S, Liu T, Ou D, O'Rourke MO. Effect of aging on aortic morphology in populations with high and low prevalence of hypertension and atherosclerosis. Am J Pathol. 1991;139:1119-1129. [Abstract]
32. Aronberg DJ, Glazer HS, Madsen K, Sagel SS. Normal thoracic aortic diameters by computed tomography. J Comput Assist Tomogr. 1984;8:247-250. [Medline] [Order article via Infotrieve]
33. Singer RB, Siber FJ, Brown AE. Mortality in 4100 insured applicants with ECG and chest x-ray. Trans Assoc Life Ins Med Dir Am. 1982;62:180-193.
34. Mohiaddin RH, Schoser K, Amanuma M, Burman ED, Longmore DB. MR imaging of age-related dimensional changes of thoracic aorta. J Comput Assist Tomogr. 1990;14:748-752. [Medline] [Order article via Infotrieve]
35.
Gerstenblith G, Fredriksen J, Yin FCP, Fortuin NJ, Lakatta EG,
Weisfeldt ML. Echocardiographic assessment of a normal adult aging
population. Circulation. 1977;56:273-278.
36.
Valdez RS, Motta JA, London E, Martin RP, Haskell WL, Farquhar
JW, Popp RL, Horlick L. Evaluation of the echocardiogram as an
epidemiologic tool in an asymptomatic population.
Circulation. 1979;60:921-929.
37. Arcaro G, Laurent S, Jondeau G, Hoeks AP, Safar ME. Stiffness of the common carotid artery in treated hypertensive patients. J Hypertens. 1991;9:947-954. [Medline] [Order article via Infotrieve]
38. Kawasaki T, Sasayama S, Yagi S, Asakawa T, Hirai T. Noninvasive assessment of the age related changes in stiffness of major branches of the human arteries. Cardiovasc Res. 1987;21:678-687. [Medline] [Order article via Infotrieve]
39. Sonesson B, Hansen F, Stale H, Länne T. Compliance and diameter in the human abdominal aorta: the influence of age and sex. Eur J Vasc Surg. 1993;7:690-697. [Medline] [Order article via Infotrieve]
40. Horejs D, Gilbert PM, Burstein S, Vogelzang RL. Normal aortoiliac diameters by CT. J Comput Assist Tomogr. 1988;12:602-603. [Medline] [Order article via Infotrieve]
41. O'Rourke MF. Arterial Function in Health and Disease. Edinburgh, UK: Churchill Livingstone; 1982:27-32.
42. O'Rourke MF, Avolio AP, Lauren PD, Yong J. Age related changes of elastic lamellae in the human thoracic aorta. J Am Coll Cardiol. 1987;9:53A. Abstract.
43.
Wolinsky H. Long term effects of hypertension on rat aortic
wall and their relation to concurrent aging changes; morphological and
chemical studies. Circ Res. 1972;30:301-309.
44. Hornebeck W, Adnett JJ, Robert L. Age dependent variation of elastin and elastase in aorta and human breast cancers. Exp Gerontol. 1978;13:293-298. [Medline] [Order article via Infotrieve]
45. O'Rourke MF. Pulsatile arterial hemodynamics in hypertension. Aust N Z J Med. 1976;6(suppl II):II-40-II-48.
46. Kaplan N. Clinical Hypertension. 3rd ed. Baltimore, Md: Williams & Wilkins; 1982;82-92.
47. Sandor B. Fundamentals of Cyclic Stress and Strain. Madison, Wis: University of Wisconsin; 1972:3.
48.
Bader H. Dependence of wall stress in the human thoracic aorta
on age and pressure. Circ Res. 1967;20:354-361.
49.
Tell GS, Rutan GH, Kronmal RA, Bild DE, Polak JF, Wong ND,
Borhani NO. Correlates of blood pressure in community-dwelling older
adults. Hypertension. 1994;23:59-67.
50. Dunn FG, Chandraratna P, deCarvallo J, Basta LL, Frohlich ED. Pathophysiologic assessment of hypertensive heart disease with echocardiography. Am J Cardiol. 1977;39:789-795. [Medline] [Order article via Infotrieve]
51.
Savage D, Drayer J, Henry W, Mathews EC, Ware JH, Gardin JM,
Cohen ER, Epstein SE, Laragh JH. Echocardiographic assessment of
cardiac anatomy and function in hypertensive subjects.
Circulation. 1979;59:623-632.
52. Pearson AC, Gudipati C, Nagelhout D, Sear J, Cohen JD, Labovitz AJ. Echocardiographic evaluation of cardiac structure and function in elderly subjects with isolated systolic hypertension. J Am Coll Cardiol. 1991;17:422-430. [Abstract]
53.
Peterson LH, Jensen RE, Parnell J. Mechanical properties of
arteries in vivo. Circ Res. 1960;8:622-634.
54. Safar ME. Pulse pressure in essential hypertension: clinical and therapeutic implications. J Hypertens. 1989;7:768-776.
55. Pannier B, Brunel P, Aroussy WE, Lacolley P, Safar ME. Pulse pressure and echocardiographic findings in essential hypertension. J Hypertens. 1989;7:127-132. [Medline] [Order article via Infotrieve]
56.
Baumbach GL. Is pulse pressure a stimulus for altered vascular
structure in chronic hypertension? Hypertension. 1991;18:728-729.
57.
Christensen KL. Reducing pulse pressure in hypertension may
normalize small artery structure. Hypertension. 1991;18:722-727.
58.
Psaty BM, Furberg CD, Kuller LH, Borhani NO, Rautaharju PM,
O'Leary DH, Bild DE, Robbins J, Fried LP, Reid C. Isolated systolic
hypertension and subclinical cardiovascular disease in the elderly.
JAMA. 1992;268:1287-1291.
59. Salonen R, Salonen JT. Determinants of carotid intima-media thickness: a population-based ultrasonography study in eastern Finnish men. J Intern Med. 1991;229:225-231. [Medline] [Order article via Infotrieve]
60. Silver FH, Christiansen DL, Buntin CM. Mechanical properties of the aorta: a review. Crit Rev Biomed Eng. 1989;17:323-357. [Medline] [Order article via Infotrieve]
61. Folkow B. `Structural factor' in primary and secondary hypertension. Hypertension. 1990;16:89-101.
62. Nichols WW, O'Rourke MF. McDonald's Blood Flow in Arteries: Theoretical, Experimental and Clinical Principles. 3rd ed. London, UK: E Arnold; 1990:77-142,216-269,283-359,398-437.
63.
Pietro DA, Voelkel AG, Ray BJ, Parisi AF. Reproducibility of
echocardiography. Chest. 1981;79:29-32.
64.
Kelly RP, Hatward CS, Avolio AP, O'Rourke MF. Noninvasive
determination of age-related changes in the human arterial pulse.
Circulation. 1989;80:1652-1659.
65. Isnard RN, Pannier BM, Laurent S, London G, Diebold B, Safar M. Pulsatile diameter and elastic modulus of the aortic arch in essential hypertension: a non-invasive study. J Am Coll Cardiol. 1989;13:399-405.[Abstract]
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