Search

Objectives: It has been suggested that arteries age more quickly in borderline hypertensives (BHT) than in normotensives. If this hypothesis is correct, the decrease in distensibility and compliance in the carotid artery bifurcation should be most pronounced in the carotid artery bulb, because this site is known to be the most affected by age., Design: Arterial distensibility was measured non-invasively by means of an ultrasound vessel wall moving-detector system at various sites along the carotid artery bifurcation in BHT and normotensive controls., Methods: Sixteen bifurcations of male BHT (mean age 38 years) and 15 bifurcations of normotensive age-matched controls (NTO) were studied in subjects from a population study on borderline hypertension. To evaluate age-related changes, 18 bifurcations of normotensive young male subjects (NTY; mean age 24 years) were included in the study., Results: In NTY subjects no significant variations in distensibility were found along the carotid artery bifurcation, but in NTO subjects the proximal and distal parts of the carotid artery bulb were significantly less distensible than the common carotid artery. In BHT the distensibility was significantly lower at all levels in the bulb than in the common carotid artery, and its proximal part was significantly stiffer than the rest of the bulb., Conclusions: The findings in this study indicate faster ageing of the carotid artery bifurcation in male BHT than in normotensives of comparable age. In particular, the proximal part of the carotid artery bulb, where the baroreceptors are predominantly located, is most affected by the disease.

Aim: To determine whether there are inhomogeneities in arterial wall distensibility with age and hypertension., Background: It has been known for some years that arteries lose their elasticity with increasing age and that they are less distensible in subjects with established and borderline hypertension than in age-matched controls., Results of Data Analysis: In the carotid artery changes in arterial wall properties are not homogeneously distributed along the bifurcation. Both in older subjects and in those with borderline hypertension the loss of distensibility is most pronounced in the carotid artery bulb, while in borderline hypertensives the proximal part of the bulb, where the baroreceptors are predominantly located, is more affected than other parts of the bulb. The loss of distensibility in the bulb may explain the diminished baroreceptor sensitivity observed in older subjects. The pronounced involvement of the proximal part of the bulb in the decreased distensibility in borderline hypertensives suggests that local stiffening, probably leading to disturbed baroreceptor sensitivity, may contribute to the development of hypertension in these patients. The pattern of inhomogeneities in wall distensibility in borderline hypertensives at a relatively young age (average 38 years) is similar to that seen in older normotensive subjects (average age 57 years), supporting the idea that arteries age faster in hypertensives than in normotensives., Conclusion: In management of the borderline hypertensive patient, consideration should be given to preventing early ageing of the arterial wall rather than following arterial blood pressure.

The effect of chronic administration of verapamil, following a double-blind, crossover protocol, on the distensibility and cross-sectional compliance of the common carotid artery was investigated in 19 patients with essential hypertension. Distensibility was significantly increased during verapamil treatment as compared to placebo for both left and right common carotid artery (p less than 0.01 and p less than 0.05, respectively). The cross-sectional compliance was significantly increased during verapamil treatment for the right common carotid artery (p less than 0.05). For the left common carotid artery, the difference did not reach the level of significance (p = 0.16). The common carotid artery diameter and the arterial pulse pressure were not significantly different during verapamil treatment as compared with placebo. The results of this study indicate that chronic treatment with verapamil increases distensibility and cross-sectional compliance of the common carotid artery in hypertensive subjects. These improvements have to be considered as changes in arterial wall properties because no significant differences in pulse pressure and diameter could be detected between the verapamil and placebo periods. Improved arterial wall properties could result in a better management of the flow jet from the heart, and might protect the patients from atherosclerotic complications of hypertension.

The vessel wall properties of the common carotid artery were noninvasively studied in 109 normotensive, presumed normal male and female volunteers of various ages (20-69 y) with the use of a multi-gate pulsed Doppler system. This system allows the on-line recording of velocity profiles and the relative changes in carotid artery diameter during the cardiac cycle (delta d/d). From the width of these profiles the systolic internal diameter (d) of the carotid artery can be determined. With the use of d, the maximal increase in delta d/d during systole and the pulse pressure, as measured in the brachial artery (delta p), the distensibility coefficient and the cross-sectional compliance were calculated. Both distensibility and cross-sectional compliance were significantly lower in females than in males, irrespective of age. This likely results from a stiffer arterial wall behavior in females, because the relative increase in vessel diameter during the cardiac cycle is lower in females than in males, despite the fact that their pulse pressure values are not significantly different. The carotid artery diameters were similar in men and women. The findings in the present study indicate that the common carotid artery is stiffer in females than in males of comparable age. Therefore, sex-dependent differences have to be considered in the interpretation of arterial distensibility and cross-sectional compliance.

The vessel wall properties of the common carotid artery were studied noninvasively in normotensive and borderline hypertensive male volunteers of various ages with the use of a multi-gate pulsed Doppler system. In the younger age group (20-35 y) both distensibility and cross-sectional compliance were significantly less in the borderline hypertensive group. In the older borderline hypertensive subjects (50-69 y) distensibility (p less than 0.05) and cross-sectional compliance (p = 0.06) were also less than in the control subjects. The reduced distensibility and cross-sectional compliance likely result from a decrease in arterial wall elasticity because the relative increase in common carotid artery diameter during systole is diminished in borderline hypertensives, despite the fact that their pulse pressure is similar to or higher than that in control subjects. The less pronounced differences in vessel wall properties between borderline hypertensive and normotensive volunteers in the older age group may be a consequence of the changes in these properties with age, partly masking the alterations due to borderline hypertension. Since the stiffer behavior of the common carotid artery in borderline hypertensives is associated with relatively slight changes in blood pressure, the question can be raised whether the alterations in arterial wall properties are really a result of the elevated arterial blood pressure; these alterations might develop independent of the blood pressure elevation.

Changes in distensibility and cross-sectional compliance of the common carotid artery with age were studied in 80 presumed healthy volunteers, varying in age between 20 and 69 y. The distensibility was assessed from the relative increase in arterial diameter during systole normalized with respect to the arterial pulse pressure. The cross-sectional compliance was obtained by multiplying the distensibility by the arterial diameter. The relative diameter changes of the common carotid artery during the cardiac cycle were recorded on-line with a high resolution multigate pulsed Doppler system. The arterial diameter was assessed from the width of the velocity profiles which can also be recorded on-line with this system. Arterial pulse pressure was determined from brachial artery cuff blood pressure measurements. Both distensibility and cross-sectional compliance of the common carotid artery decreased linearly with age, starting in the third age decade. The reduction in the latter parameter was less pronounced, probably as a consequence of an increase in arterial diameter with age.

The effects of verapamil (a calcium antagonist) and nebivolol (a novel, selective beta 1-adrenoceptor blocker) on carotid artery distensibility and cross-sectional compliance were studied non-invasively in hypertensive patients with the use of a high-resolution multigate pulsed Doppler system. Arm blood pressure measurements were made with an automated device (Dinamap). After a 4-week washout period, 19 patients (aged 21-73 years) with essential hypertension entered a double-blind randomized placebo-controlled crossover study with 120 mg verapamil or placebo three times a day for 4 weeks. After the administration of verapamil, carotid artery distensibility and cross-sectional compliance were significantly larger (P less than 0.05) than after placebo. Using the same protocol, 29 patients (aged 25-70 years) were given 5 mg nebivolol or placebo once a day for 4 weeks. After the administration of nebivolol, carotid artery distensibility and cross-sectional compliance were significantly larger (P less than 0.05) than after placebo. In both studies no significant differences in diameter and pulse pressure were found between placebo and verapamil or nebivolol. Blood pressure was decreased similarly with both verapamil and nebivolol. These results indicate that both verapamil and nebivolol favourably influence carotid artery distensibility and cross-sectional compliance of the common carotid artery, resulting in a better management of the systolic pressure pulse. The improved carotid artery distensibility may help to protect the patient against atherosclerotic complications of hypertension.

The vessel wall properties of the common carotid artery were noninvasively studied in 53 normotensive, presumed normal boys of various ages (4-19 yr) with the use of a multigate pulsed Doppler system. This device allows the on-line recording of velocity profiles and the relative changes in carotid artery diameter during the cardiac cycle. From the width of these profiles, the internal diameter of the carotid artery can be determined. With the use of internal carotid artery diameter, relative changes in carotid artery diameter during the cardiac cycle, and pulse pressure the pulse pressure, as measured in the brachial artery, the distensibility coefficient and the cross-sectional compliance were calculated. The children were allotted to three different age groups: group I (4-10 yr), group II (11-14 yr), and group III (15-19 yr). In the older children (group III) the systolic arterial pressure and the pulse pressure were significantly higher than in groups I and II. The carotid artery diameter was significantly larger and the distensibility coefficient was significantly smaller in group III than in groups I and II. The cross-sectional compliance was not significantly different in the age groups, which can be explained by the larger artery diameter in the older age group. The findings indicate that the carotid artery wall is less distensible in adolescents than in younger children. The subjects in group III showed similar carotid artery wall properties as the young adults (aged 20-34 yr) in a previous study. Therefore, it is likely that in adolescents the vascular system can be considered as mature as far as the arterial wall properties are concerned.