Biomedical subjects

S Laurent

Publications and source records attributed to S Laurent.

At least 145 records · Page 8Linked to original sources

PubMed1994

Sympathetic activation decreases medium-sized arterial compliance in humans.

This study used a precise noninvasive method in normotensive humans to determine the effects of sympathetic activation on arterial compliance. A recently developed, high-resolution echo-tracking system capable of measuring systolic/diastolic variations of arterial diameter was coupled to a Finapres system and used to calculate instantaneous systolic/diastolic pressure-diameter and compliance-pressure curves for a muscular medium-sized artery, the radial artery. Two standardized tests of sympathetic system activation, a cold pressor test (2 min) and a mental stress test (2 min of mental arithmetic), were performed at an interval of 8 days in random order in nine healthy volunteers [30 +/- 9 (SD) yr]. Radial arterial parameters were recorded every 30 s for 9 min, which included 2 min of cold pressor test or mental stress test. During both tests, radial arterial mean diameter did not change despite t he increase in mean arterial pressure (P < 0.001); stroke change in diameter decreased (P < 0.01), whereas pulse pressure increased (P < 0.01). Arterial compliance, calculated for the instantaneous level of mean arterial pressure, decreased significantly (P < 0.01). Compliance (C) calculated at 100 mmHg (C100) was arbitrarily chosen as a reference point for comparing compliance among the different periods of the test. C100 decreased significant (P < 0.05) during both tests (from 2.93 +/- 1.27 to 2.04 +/- 0.94 and from 3.29 +/- 1.73 to 2.63 +/- 1.55 mm2.mmHg-1.10(-3) during mental stress and the cold pressor test, respectively). These results indicate that sympathetic activation is able to decrease radial arterial compliance in healthy subjects. The reduction in arterial compliance probably resulted from complex interactions between changes in distending blood pressure and changes in radial arterial smooth muscle tone.

Adult↗

PubMed1994

Early disturbance of baroreflex control of heart rate after tail suspension in conscious rats.

Experiments were performed on conscious chronically instrumented rats maintained on tail suspension to determine the time course of changes in baroreceptor control of heart rate produced by this procedure. Pressor responses were elicited by bolus injections of graded doses of phenylephrine and sodium nitroprusside, permitting evaluation of the totality of the sigmoidal curve relating mean arterial pressure to heart rate. Compared with control rats maintained at 0 degrees, rats maintained at 20 degrees using tail suspension for 24 h showed a significant reduction in reflex gain (-3.9 +/- 0.1 vs. -5.8 +/- 0.3 beats/min; P < 0.001) together with a reduction in the upper (472 +/- 11 vs. 512 +/- 5 beats/min; P < 0.01) and lower (270 +/- 3 vs. 284 +/- 2 beats/min; P < 0.01) plateaus of the sigmoidal curve. In three groups of rats, the sigmoidal curve was studied successively after returning for 1, 24, and 48 h at 0 degrees. The observed change in the gain of the reflex returned toward control values after 48 h, whereas the other parameters characterizing the sigmoidal curve did not change significantly. Transient but significant modifications of heart rate (tachycardic response) after the immediate return to the horizontal position were observed. The study provides evidence that 1) a significant change of the totality of the sigmoidal curve characterizing baroreceptor control of heart rate occurs very early after tail suspension in rats and 2) the gain of the reflex is restored during the 48 h after release of tail suspension, whereas the other parameters characterizing the curve, particularly the plateaus, remain altered.

Animals↗

PubMed1994

Elastic modulus of the radial artery wall material is not increased in patients with essential hypertension.

Hypertension is known to decrease arterial distensibility and systemic compliance. However, the arterial tree is not homogeneous, and it has been shown that the medium-size radial artery does not behave like the proximal, elastic, large, common carotid artery. Indeed, radial artery compliance in hypertensive patients (HTs) has been shown to be paradoxically increased when compared with that in normotensive control subjects (NTs) at the same blood pressure level. To determine whether this increase was due to hypertension-related hypertrophy of the arterial wall, radial artery functional and geometric parameters from 22 NTs (mean +/- SD, 44 +/- 11 years) were compared with those from 25 age- and sex-matched never-treated essential HTs (48 +/- 12 years) by using a high-precision ultrasonic, echo-tracking system coupled to a photoplethysmograph (Finapres system), which allows simultaneous arterial internal diameter, intima-media thickness, and finger blood pressure measurements. When the values for HTs were compared with those of NTs at their respective mean arterial pressures, HTs had similar internal diameter (2.50 +/- 0.56 versus 2.53 +/- 0.32 mm, mean +/- SD) and greater intima-media thickness (0.40 +/- 0.06 versus 0.28 +/- 0.05 mm, P < .001) measurements and increased arterial wall cross-sectional areas (3.79 +/- 1.14 versus 2.45 +/- 0.57 mm2, P < .001). Circumferential wall stress was not significantly different between the two groups. Compliance calculated for a given blood pressure, ie, 100 mm Hg (C100), was greater in HTs than NTs (3.46 +/- 2.41 versus 2.10 +/- 1.55 m2.kPa-1 x 10(-8), P < .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1994

Carotid artery distensibility and distending pressure in hypertensive humans.

Whether the decrease in large-artery distensibility observed in hypertensive patients is due primarily to an increase in distending pressure or to hypertension-induced changes in structural properties has been much debated. We determined noninvasively the diameter-pressure curve of the common carotid artery over the systolic-diastolic range by continuously recording both the pulsatile changes in internal diameter (high-resolution echo-tracking system) and, simultaneously on the contralateral artery, the pressure waveform (high-fidelity applanation tonometry). We then derived the distensibility/pressure curve and compared arterial distensibility in 14 normotensive subjects and 15 age- and sex-matched hypertensive subjects at their respective mean arterial pressures (MAP) and at a common distending pressure: 100 mm Hg. Distensibility decreased as blood pressure increased, and distensibility at MAP was significantly lower in hypertensive than in normotensive subjects (7.8 +/- 0.7 versus 11.7 +/- 1.7 kPa-1.10(-3), mean +/- SEM; P < .05). In hypertensive subjects, the distensibility-pressure curve was shifted toward higher levels of blood pressure, and a large part of the curve overlapped that of normotensive subjects. No significant downward shift of the distensibility-pressure curve was observed in hypertensive subjects, and distensibility at 100 mm Hg was not significantly different from that of normotensive subjects (10.0 +/- 1.0 versus 9.0 +/- 1.1 kPa-1.10(-3)). Distensibility at 100 mm Hg decreased with aging (P < .05) and was not reduced in hypertensive subjects compared with normotensive subjects after adjustment for age.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1994

[Measurement of the vascular mass of the human radial artery by ultrasonics].

OBJECTIVE: To determine the reproducibility of radial artery mass (RAM), in hypertensive patients. DESIGN AND METHODS: In 49 patients, RAM was measured using a high resolution echotracking device (Nius-02) which allows noninvasive measurement of diameter and wall thickness of the radial artery. RAM was validated in vitro by comparing weight of arterial segments to ultrasonographic measurement and determined as RAM = r (pi Re2-pi Ri2) where r is the arterial wall density (1.06 g/cm3), and Re and Ri are values of internal and external radii, respectively. Repeatability coefficient (RC2 = SDi2/n) was 1.3 mg. RESULTS: Blood pressure was (mean +/- SD) 146 +/- 19/85 +/- 15 mmHg, radial arterial diameter was 2,449 +/- 376 microns, radial wall thickness was 302 +/- 68 microns, RAM was 28 +/- 9 mg (range 13-43 mg). CONCLUSION: These results indicate that radial artery mass can be measured using a high resolution echotracking device.

Humans↗

PubMed1994

[Arterial compliance is not diminished in hypertensive patients when compared at the same level of blood pressure].

Whether the decrease in large artery compliance, observed in hypertensive patients (HT), is due to an increase in distending pressure or to intrinsic alterations of the vascular wall remains much debated. We determined the diameter-pressure curve of the common carotid artery over the systolic-diastolic range, then derived the compliance-pressure curve, in order to compare arterial compliance in normotensive subject (NT) and in HT, for a common level of distending blood pressure: 100 mmHg (isobaric compliance). Fourteen NT and 15 never treated essential HT were included in the study. The diameter-pressure curve of the common carotid artery was determined non-invasively by simultaneously and continuously recording the systolic-diastolic changes in internal diameter (using a high resolution echotracking system) and pressure waveform (using high fidelity applanation tonometry on the contralateral artery) over 4-6 cardiac cycles. The level of MAP of the carotid pressure waveform was determined electronically and set equal to mean brachial pressure. Compliance-pressure curve was then derived from the pressure-diameter curve in order to determine compliance (C) for any given level of blood pressure, particularly MAP (CMAP) and 100 mmHg (C100). Despite the considerable differences in blood pressure, the compliance-pressure curve of HT was not different from that of NT. CMAP decreased with aging (p < 0.001) and MAP (p < 0.001). According to age, CMAP was reduced in HT as compared to NT (84 +/- 49 vs 116 +/- 52 mm2.mmHg.10(-3) p < 0.01). C100 decreased with aging (p < 0.05) but not with MAP. According to age, C100 was not reduced in hypertensives.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1994

[Hemodynamic effects of chronic treatment by cilazapril in normotensive patients with obliterative arterial diseases of the lower limbs].

OBJECTIVE: To determine whether long-term treatment with cilazapril (CIL) may improve pulse pressure (PP), arterial compliance and ankle-arm systolic index (AAI) in patients with lower-extremity arterial disease (LEAD). Indeed, in both systolic hypertension and LEAD, the increase in pulse pressure has been attributed to a reduced compliance. DESIGN AND METHODS: Thirteen patients (age: 65 +/- 5 yrs; AAI: 0.78 +/- 0.15; m +/- SD) were included in a double-blind randomized parallel study to compare the effects of a 6 month treatment with CIL (10 mg per day; n = 6) to those of placebo (PL; n = 7) Blood pressure, AAI and arterial compliance were determined at baseline (MO) and after 3 (M3) and 6 months (M6). Common carotid (CC) and common femoral (CF) artery compliances were noninvasively determined from pulsatile changes in arterial diameter (Wall Track System, Hoeks et al., 1990) and pressure (PP). RESULTS: Both groups were comparable at MO. Compared to PL, CIL significantly reduced PP (-22 +/- 4 vs -2 +/- 9 mmHg) and MAP (-16 +/- 11 vs -4 +/- 7 mmHg) and improved CC (+54 +/- 34 vs +5 +/- 21 mm2.mmHg-1.10(-3)) at M6. Weaker effects were observed at M3. No significant changes in AAI and CF compliance were observed. CONCLUSIONS: A direct effect of CIL on the large artery wall was suggested by 1) a greater reduction in PP than in MAP and 2) a disproportionately greater improvement in CC compliance compared with the reduction in distending pressure (MAP). These results indicate that long-term treatment with CIL may improve large artery function in patients with LEAD.

Adult↗

PubMed1994

Intrinsic modifications of the brachial and radial arteries in hypertensive humans.

The properties of vessel walls of brachial and radial arteries were studied noninvasively, using 2 original pulsed ultrasound echo-tracking systems based on Doppler shift, in an investigation comparing 32 normotensive controls and 50 age-matched hypertensive patients. The 2 groups did not differ with respect to sex, total and high-density lipoprotein cholesterol, blood glucose, and smoking habits. Whereas noninvasive measurements of blood pressure indicated that both mean arterial pressure and pulse pressure were significantly increased in the arterial tree of the hypertensive forearm, end-diastolic diameter and pulsatile changes of the brachial and radial arteries remained within the normal range. The finding was more pronounced at the site of the radial artery in which: (i) pulsatile changes of blood pressure (documented from Finapres method) were significantly higher than those of the brachial artery, yet (ii) indices of arterial stiffness (compliance and distensibility) remained within the normal range. For the branchial artery, distensibility was significantly reduced (p = 0.01), whereas no significant change in compliance was observed. The study provides evidence that, in subjects with essential hypertension, the mechanical properties of the brachial and the radial arteries are not exclusively related to the level of blood pressure, and differ according to the arterial segment studied.

Adult↗

PubMed1994

Appraisal of the modalities used to evaluate an initial abnormal Papanicolaou smear.

OBJECTIVE: To examine the efficacy of the different modalities used to evaluate an initial abnormal Papanicolaou smear. METHODS: The study population comprised 214 nonpregnant women referred with a Papanicolaou smear diagnosis of cervical intraepithelial neoplasia. Each patient was evaluated by a repeat Papanicolaou smear, colposcopy, and colposcopically directed cervical biopsies. Immediate loop excision was performed to remove the entire transformation zone in all patients. Kappa statistics were calculated to determine agreement among the modalities, and logistic regression was used for determining relative risks (RR). RESULTS: There was 53% agreement between the initial and repeat Papanicolaou smears. When low-grade squamous intraepithelial lesion (SIL) was diagnosed by Papanicolaou smear, there was 89% agreement with the colposcopic impression. However, a colposcopic impression of high-grade SIL was found in only one-third of the women diagnosed with high-grade SIL by Papanicolaou smear. A comparison of the histology of the cervical biopsy and the loop specimen revealed 57% agreement. Univariate analysis indicated that each modality was able to predict the RR of high-grade dysplasia in the loop specimen at a statistical significance level of .05. A colposcopic impression of high-grade dysplasia conferred an RR of 7.43 (95% confidence interval [CI] 2.17-25.49) for high-grade dysplasia in the loop specimen. An initial Papanicolaou smear diagnosis of high-grade SIL did not contribute to the multivariate model for calculating the risk of high-grade dysplasia, as the RR was 1.6 (95% CI 0.68-3.81). CONCLUSION: Patients with an initial Papanicolaou smear showing low-grade SIL would benefit from a repeat Papanicolaou smear and colposcopically directed biopsies before proceeding with loop diathermy. In contrast, patients with a colposcopic impression of high-grade dysplasia combined with high-grade SIL on Papanicolaou smear appear to be candidates for immediate loop excision.

Adolescent↗

PubMed1993

Isobaric compliance of the radial artery is increased in patients with essential hypertension.

OBJECTIVES: Hypertension is known to decrease arterial elasticity and systemic compliance. However, the arterial tree is not a homogeneous system, and whether a distal medium-sized artery such as the radial artery behaves like proximal arteries has not been determined. The aims of the present study were, first, to characterize non-invasively the mechanical properties of the radial artery through the determination of the pressure-diameter curve, the distensibility-pressure curve and the compliance-pressure curve, and, secondly, to compare untreated hypertensive patients with normotensive subjects. METHODS: A new high-precision echo-tracking device was developed which allows the diameter of peripheral arteries to be measured continuously. By relating the changes in internal diameter (cross-sectional changes) to those in blood pressure, the cross-sectional arterial compliance could be determined. PARTICIPANTS: Seventy-eight untreated mild or moderate essential hypertensive patients aged 24-78 years were compared with 44 normotensive subjects aged 22-81 years. In order to increase the database and provide independent assessments of the variables examined, the cross-sectional study was performed independently using a standardized procedure in three different research centres. RESULTS: The major finding was that diameter, distensibility and compliance of the radial artery of hypertensive patients were not significantly different from those of normotensive controls when the two populations were studied at their mean arterial pressure. Furthermore, when the two populations were compared for the same level of blood pressure, using distensibility--and compliance--pressure curves, it was clear that isobaric distensibility and compliance of hypertensives were not significantly lower than those of normotensives, being either unchanged or higher. CONCLUSIONS: These findings are in contrast with the well-known decrease in compliance of proximal large arteries due to hypertension. Whether such a difference between proximal large arteries and distal medium-sized arteries may be related to the structural vascular changes observed with long-standing hypertension is still difficult to analyse in humans, and requires further investigation.

Adult↗

PubMed1993

Effects of clonidine on plasma catecholamines and neuropeptide Y in hypertensive patients at rest and during stress.

Neuropeptide Y (NPY), a potent vasoconstrictor agent reported to be released, in addition to norepinephrine (NE), by sympathetic nerve endings during stress, may contribute to the pressor response to various stimuli. The objectives of this study were to determine (a) whether plasma NPY concentrations are altered during different types of stress (cold pressor test, mental stress, and active orthostatism) and (b) whether clonidine, via its central sympatholytic effect, affects the stress-induced blood pressure, NPY, and/or catecholamine changes. Eighteen untreated patients with mild essential or borderline hypertension participated in an acute randomized, double-blind, parallel study. The blood pressure and heart rate were recorded during three control periods, each followed by either a cold pressor test (CPT), a mental stress test (MS: mental arithmetic), or active orthostatism (AO), performed in a random order. Venous blood samples for catecholamines and NPY determination were taken at the end of each control and test period. This entire procedure was repeated after oral clonidine (150 micrograms) or placebo. Before treatment, a CPT, MS, or AO increased the blood pressure to the same extent. The stress-induced increase in plasma NE was greater during AO (+99 +/- 23%) than during CPT (+35 +/- 8%) and MS (+55 +/- 12%). The stress-induced increase in plasma epinephrine was only significant during MS (+142 +/- 69%). A small but significant increase in NPY (p < 0.05) was observed during AO only (+10 +/- 7%). Compared to placebo, clonidine significantly decreased the basal blood pressure and the pressor response to CPT, but did not change the pressor response to MS and AO.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1993

Microgravity and orthostatic intolerance: carotid hemodynamics and peripheral responses.

A ground-based model [24 h of bed rest (BR) with head-down tilt (HDT)] was used to investigate the cardiovascular deconditioning responsible for orthostatic intolerance, frequently observed after weightlessness flights. This experimental deconditioning is shown to be distinguished by an increase of mean blood pressure (P < 0.05), with increased total peripheral resistances (TPRs). Systolic tangential tension of the carotid arterial wall, cardiac output and frequency (spectral analysis), and plasma norepinephrine and epinephrine were not significantly altered, while plasma dopamine was increased (P < 0.05). Cardiovascular homeostasis was challenged before and after 24 h of BR with HDT through -40 mmHg lower body negative pressure (LBNP). Systolic tangential tension of the carotid wall was decreased, with a decrease of systolic pressure and cardiac output; increased heart rate was likely due to an increase of sympathetic drive with a decrease of vagal braking. The overall picture was not changed after 24 h of BR with HDT, except for a lack of increase of TPRs: their increase (+13.7%, P < 0.05) before was no longer observed after (-2.6%) 24 h of BR with HDT. This apparent deficiency cannot be explained. However, a heterogeneity in the response of TPR should be considered because the magnitude of the increase of blood pressure to cold pressor test was the same after 24 h of BR with HDT as it was before.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1993

Arterial alterations with aging and high blood pressure. A noninvasive study of carotid and femoral arteries.

Noninvasive in situ evaluations of pulsatile changes of blood pressure and arterial diameter were performed at the sites of the common carotid and femoral arteries in a population of 78 untreated normotensive and hypertensive subjects. Arterial segments were studied by using an original echo-tracking technique for internal diameter and validated applanation tonometry for local pulse pressure measurements. Whereas mean arterial pressure is known to be identical in all parts of the arterial tree, pulse pressure was significantly lower in the carotid (52.7 +/- 2.2 mm Hg) than in the brachial (62.0 +/- 2.0 mm Hg) or femoral (62.5 +/- 2.5 mm Hg) arteries. Despite a higher pulse pressure and diastolic diameter, the femoral artery had a lower pulsatile change in diameter (3.47 +/- 0.18% versus 6.07 +/- 0.28%; p < 0.0001) and distensibility coefficient (9.36 +/- 0.58 versus 21.60 +/- 1.75 x 10(-3) kPa-1) than the carotid artery. Local cross-sectional compliance of the carotid artery was higher than that of the femoral artery (7.42 +/- 0.46 versus 6.20 +/- 0.28 m2.kPa-1.10(-7); p < 0.05). Whereas age was strongly correlated with arterial parameters at the site of the carotid artery (pulse pressure: r = 0.54, p < 0.0001; pulsatile change in arterial diameter: r = -0.62, p < 0.0001; distensibility coefficient: r = -0.70, p < 0.0001), no significant correlation was observed at the femoral artery. Mean blood pressure was the second factor of carotid artery alterations: the higher the mean blood pressure, the lower the distensibility of this artery (r = -0.36, p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1993

A circulating substance cross-reacting with antiimidazoline antibodies. Detection in serum in relation to essential hypertension.

It has been shown in various mammal species that clonidine, a well known centrally acting hypotensive agent, acts through the activation of imidazoline receptors (IRs) in the nucleus reticularis lateralis (NRL) of the brainstem. Specific binding sites sensitive to imidazolines and insensitive to catecholamines have been detected in rat and bovine, as well as human brains. An endogenous ligand, other than catecholamines, should exist for these IRs. Such a ligand could play a role in the pathophysiology of human essential hypertension. Therefore, we developed two RIAs with polyclonal and monoclonal anticlonidine antibodies. These antibodies presented specificity spectra similar to that of the IRs: they bound imidazolines and not catecholamines at all. These RIAs were used to detect imidazoline-like immunoreactivity in the human serum. Immunoreactive substance was measured in 26 normotensive subjects' sera, and specificity of interaction between antibodies and sera was verified. None of the known endogenous substances tested so far were able to interact with the two antibodies. Immunoreactivity in 32 essential hypertensive patients' sera proved higher in approximately 30% of cases. Values of immunoreactivity positively correlated with the mean arterial pressure values. This study demonstrates the existence of an "imidazoline-like" immunoreactive substance in the human serum with high levels in some hypertensive patients.

Adult↗

PubMed1993

Cardioreparation and the concept of modulating cardiovascular structure and function.

Hypertension and atherosclerotic cardiovascular disease represent major global health problems. Practising physicians are challenged daily by patients suffering adverse cardiovascular events, such as myocardial infarction, stroke, heart failure and sudden cardiac death. Major risk factors have been identified of which the most important is left ventricular hypertrophy. In recent years, growth factors, regulatory peptides and effector hormones of the renin-angiotensin-aldosterone system have been identified as important modulators of cell growth and behaviour. It therefore follows that a major emphasis has been placed on the importance of abnormalities in organ structure as the primary basis for impaired function of the heart and vasculature, including large and medium sized arteries and resistance vessels, or arterioles. The concept of reparation recognizes the importance of abnormalities in tissue structure to the functional basis of disease. It suggests that the structurally remodelled heart and vasculature can be restored to, or toward, normal structure and function by suitable therapy. Experimental and clinical trials which address this premise are reviewed herein.

Animals↗

PubMed1993

Behaviour of conduit arteries in hypertension.

Through an increase in vascular resistance, changes of the small arteries are responsible for the evaluation of mean arterial pressure in hypertension. However, the amplitude of the pressure oscillation, i.e. pulse pressure, is influenced by other hemodynamic mechanisms, which involve large arteries through a decrease in compliance and an increase in wave reflections. Consequently, structural and functional alterations of the large arteries are responsible in hypertensive subjects for an increase in the amplitude of the pressure oscillation and a disproportionate increase in systolic pressure over diastolic blood pressure through arterial (and not arteriolar) changes. Such findings not only contribute to a better understanding of the relationships between vascular structure and function and the level of blood pressure but also to better interprate the hypertensive complications, particularly those related to the heart and larges vessels.

Animals↗

PubMed1992

[Do converting enzyme inhibitors differ from each other in the treatment of hypertension?].

Novel angiotensin converting enzyme inhibitors (ACE inhibitors) have recently been commercialized and the question arises whether differences in pharmacodynamic and pharmacokinetic properties should lead to specific therapeutic choices. To our knowledge there is no data which allows the physician to conclude to any different antihypertensive efficacy when ACE inhibitors are used at adequate dosage. Their pharmacokinetic characteristics may differ at every level: absorption, distribution, metabolism and excretion. Differences in chemical structure may also influence their diffusion in various tissues, therefrom the amplitude and duration of inhibition of angiotensin II at these sites. The duration of maximum blockade of ACE and the amplitude of residual blockade may theoretically influence the duration of the hypotensive effect and the number of daily dosages. Once-daily administered long acting ACE inhibitors keep their antihypertensive action through the whole 24-hour period, during chronic treatment. The theoretical advantage of such a property is an improved control of 24-hour blood pressure. However, no study, to our knowledge, concluded to any difference between long acting ACE inhibitors as far as this parameter was concerned. In addition, except captopril which has been reported to induce major untoward effects at the time high dosages were introduced, ACE inhibitors do not seem to bear different undesirable effects.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed1992

[Effects of aging on arterial function in man].

The structure of arteries changes with age. Gradual disappearance of elastic fibres facilitates dilatation of the arterial lumen and increase in length of the vessels. Simultaneously, the arterial wall becomes thicker, but it is often difficult to distinguish the changes due to ageing from those caused by atherosclerosis. These structural alterations result in a greater rigidity of the arteries, which can now be evaluated by non-invasive segmental methods. This shows that ageing does not have the same functional effects on wide-caliber elastic arteries and on middle-sized muscular arteries. The increase of systolic arterial pressure observed in the elderly is a consequence of structural and functional changes in the arterial system.

Aged↗