Atherosclerosis 153 2000 99 – 106
Effect of hypertension and risk factors on diameters of abdominal aorta and common iliac and femoral arteries in middle-aged
hypertensive and control subjects A cross-sectional systematic study with duplex ultrasound
Markku J. Pa¨iva¨nsalo
a,
, Jukka Merikanto
a
, Tapani Jerkkola
b,c
, Markku J. Savolainen
b,c
, Asko O. Rantala
b,c
, Heikki Kauma
b,c
, Mauno Lilja
b,c
, Antti Reunanen Y.
d
, Antero Kesa¨niemi
b,c
, Ilkka Suramo
a
a
Departments of Diagnostic Radiology, Uni6ersity of Oulu, FIN-
90220
, Oulu, Finland
b
Department of Internal Medicine, Uni6ersity of Oulu, FIN-
90220
, Oulu, Finland
c
Biocenter Oulu, Uni6ersity of Oulu, FIN-
90220
, Oulu, Finland
d
Social Insurance Institution Research and De6elopment Unit, FIN-
00381
Helsinki, Finland Received 30 April 1999; received in revised form 22 November 1999; accepted 5 January 2000
Abstract
There is a general tendency towards atherosclerosis and arterial dilatation in older age, and high blood pressure also tends to increase arterial diameters. The purpose of this study was to examine the effect of hypertension and other cardiovascular risk
factors on aortic, common iliac and common femoral artery diameters. The diameters of the abdominal aorta and the iliac and femoral arteries and the extent of echogenic plaques in the aorta and the iliac arteries down to groin level were evaluated with
ultrasound in 1007 middle-aged 40 – 60 years men 505 and women 502, 496 with arterial hypertension and 511 controls. Twenty-eight subjects were excluded because of poor visualization. Men had significantly larger diameters of the abdominal aorta
mean 21.3 9 2.8 vs. 17.8 9 1.3 mm and the common iliac 13.4 9 2.0 vs. 12.2 9 1.2 and common femoral arteries 11.0 9 1.4 vs. 9.7 9 0.9 than women P for all B 0.001, but arterial diameter was also related to the subject’s size. Atherosclerotic plaques, age
and height were associated with the diameter of the abdominal aorta in men, while high body mass index BMI had less significance. The diameter of the aorta was larger in hypertensive men aged 56 – 60 than in controls of the same age. In women,
height, BMI and diastolic blood pressure DBP were associated with the diameter of the aorta, while systolic blood pressure SBP had less and age no effect. Age, plaques, height, BMI, DBP and SBP were associated with the diameters of the common
iliac arteries in both genders, while smoking had an inverse correlation. The results on lipid values were inconsistent and an abnormal glucose tolerance test proved nonsignificant. In conclusion, arterial size measured as a diameter related to the subject’s
size was larger in men. Age, arterial plaques and blood pressure increased arterial diameter significantly. However, the hypertensive disease itself had only a minimal effect. The changes were smaller in women than in men. © 2000 Elsevier Science
Ireland Ltd. All rights reserved.
Keywords
:
Ultrasound; Aorta; Iliac arteries; Plaques; Diameters; Hypertension www.elsevier.comlocateatherosclerosis
1. Introduction
Ultrasound US often shows plaques in the abdomi- nal aorta and the iliac and femoral arteries as signs of
atherosclerosis, which may sometimes result in arterial obliteration, dilation or aneurysm [1]. There is a general
tendency towards arterial dilation in older age [2 – 5]. The purpose here was to examine the effect of hyper-
tension and other risk factors on the diameters of the aorta and the common iliac and common femoral
arteries in a population-based series of randomly age- stratified selected 40- to 60-year-old men and women
with an established diagnosis of arterial hypertension, and controls.
Corresponding author. Fax: + 358-8-3155420. 0021-915000 - see front matter © 2000 Elsevier Science Ireland Ltd. All rights reserved.
PII: S0021-91500000374-9
2. Methods
2
.
1
. Population From the defined population of the City of Oulu,
treated hypertensive patients of both sexes aged 40 – 60 years and age- and sex-matched controls were recruited
for carotid [6] and abdominal ultrasound examinations as part of a survey on the cardiovascular risk factors
OPERA, Oulu Project Elucidating the Risk of Atherosclerosis. The treated hypertensives 300 men
and 300 women were randomly selected from the Social Insurance Institute’s register for the reimburse-
ment of antihypertensive medication, and the controls from the same organization’s register of all inhabitants
of the City of Oulu about 100 000 persons as de- scribed in detail previously [7]. The initial population
consisted of 1200 subjects. The overall participation rate was 85.9, and the aorta and the iliac arteries were
examined in 1007 subjects, i.e. 505 men, 502 women, 496 with arterial hypertension and 511 controls.
The procedure for blood pressure measurement was in agreement with the American Society of Hyperten-
sion [8]. All blood pressure measurements were recorded with an automatic oscillometric blood pres-
sure recorder Dinamap; Critikon, Ascot, UK. The resting blood pressure was measured three times at
1-min intervals on the right arm after patient had been seated for at least 5 min. The mean of the three sitting
blood pressure measurements was used in the analysis. BMI was calculated as weight in kilograms divided by
height in square meters. Details about the smoking habits, alcohol consumption, use of medications, and
past medical history were sought in a questionnaire. A wide range of laboratory analyses were conducted. Af-
ter the fasting blood had been drawn, the subjects were given a 75-g glucose load. Both 1- and 2-h glucose and
insulin concentrations were determined. The glucose concentrations were measured with the glucose dehy-
drogenase method Diagnostica; Merck, Darmstadt, Germany. Plasma lipids and lipoproteins were ana-
lyzed as described in the Lipid Research Clinic Pro- gram’s Manual of Laboratory Operations [9].
The mean duration of hypertension was 6.9 years SD 4.7 years, range 0.15 – 32.6 years. Of the hyperten-
sive subjects, 262 were on selective b-blocking medica- tion, 210 on angiotensin-converting enzyme inhibitors,
190 on thiatzide diuretics, 125 on calcium channel blockers and 31 on non-selective b-blocking medication
and loop diuretics, 294 women were postmenopausal.
2
.
2
. Ultrasonography of aorta and iliac arteries The data were collected over a period of 2 years. The
ultrasound examination of the aorta and iliac arteries was carried out, using a duplex ultrasound system
Toshiba Sonolayer SSD 270 with a scanning fre- quency of 5 MHz, by a single trained radiologist
blinded to the presence or absence of hypertension and following the same protocol throughout. The abdomi-
nal aorta and the common iliac and femoral arteries were imaged longitudinally and transversally. The
whole scanning procedure was recorded on a Super- VHS
video casette
recorder Panasonic.
The videotapes were analyzed later. The same radiologist
MP who performed the examinations made the mea- surements from the videotapes for the 380 successively
youngest men, and another trained radiologist JM made the measurements for the other men and for all
women. Twenty-eight of the 1007 subjects were ex- cluded because of poor visualization of the aorta and
the iliac arteries.
All measurements were made about 4 years later from the video image on the monitor of the ultrasound
device, using its electronic calipers. The maximal outer diameter lumen plus wall thicknesses of the lower
abdominal aorta was measured in the sagittal and transverse planes and the maximal diameters of both
common iliac arteries and both common femoral arter- ies in the groin in the sagittal plane. An arterial plaque
was defined as a highly or moderately echodense struc- ture encroaching into the vessel lumen. Atherosclerosis
was estimated on the basis of the plaques detected. The number of plaques was recorded and the length of each
was measured as the maximal diameter from longitudi- nal ultrasound scans of the aorta and the iliac arteries
between the level of the renal arteries and the inguinal ligament.
The moving mean technique [10] was used to assess the association of the diameters with increasing age,
and the data on one third of the subjects in the overlap- ping subgroups were used to calculate the mean. Age
was determined as of the day of the examination. The results were also calculated separately for the age
classes of 40 – 45 years, 46 – 50 years, 51 – 55 years and 56 – 60 years. The diameters were correlated with sex,
age and disease hypertensioncontrol and other risk factors.
The method of Fleiss [11,12] was used to calculate interobserver variability. First, the variance of measure-
ments in one plane by the two observers was calculated using
the formula:
M
1 2
+ M
2 2
− M
1
+ M
2 2
2, where M1 and M2 are the diameters obtained by the
two observers. The mean variance for all patients was then calculated. Interobserver variability was obtained
by taking the square root of the mean interobserver variance. The variability percentage was obtained by
dividing the variability with the mean diameter. The intrareader reproducibility of the measurements of ves-
sel diameters was assessed in 40 subjects of this series with similar age and sex distribution as in the original
series, and repeat measurements were performed from
the videotapes 1 year after the subjects’ examinations, reader blinded to the original result. The intrareader
variabilitycorrelation coefficients
Pearson’s coeffi-
cient for the vessel diameters were: 3.70.88 for the sagittal aortic diameter, 5.80.72 for the transverse
aortic diameter, 8.30.78 for the iliac and 5.20.86 for the femoral arterial diameters. The corresponding
interreader values were: 4.50.86 for the sagittal aortic diameter, 6.50.71 for the transverse aortic diameter,
8.70.76 for the iliac and 6.90.89 for the femoral arterial diameters.
2
.
3
. Statistical analyses The data were analysed with the Systat
TM
statistical program [13], which estimated the dependence of the
diameters on age by means of correlation analysis. The data are presented as means 9 SD values, unless other-
wise stated. The x
2
test was used to test the differences in frequencies, and Student’s two-tailed t-test for inde-
pendent samples to compare two groups. P-values B 0.05 were considered statistically significant. The
arterial diameters were related to the risk factor vari- ables in multivariate stepwise linear regression analysis
by backward elimination. Only the variables significant at P 5 0.15 were retained in the equation.
3. Results
