Female gender increases stiffness of elastic but not of muscular arteries in type I diabetic patients.

The reason for the particularly increased risk for cardiovascular complications in diabetic women is still unclear. We have previously found decreased distensibility of elastic arteries in type I diabetic women, indicating increased cardiac load, not seen in type I diabetic men, which might be one contributing factor. Whether the effect of gender is different in muscular arteries in type I diabetic patients has not been assessed. As estimates of arterial distensibility we measured stiffness (beta) and pressure strain elastic modulus (Ep) in the muscular common femoral artery using echo-tracking sonography in 30 women (mean age 34 years, range 20-61) and 26 men (mean age 38 years, range 22-56) with type I diabetes. The results were compared with those of 89 healthy individuals of corresponding age and gender and with previously published results from elastic arteries in these patients obtained at the same occasion. The internal common femoral diameter was significantly decreased in both diabetic men and women. In sharp contrast to the highly significant decreased distensibility of the elastic abdominal aorta and common carotid artery in the type I diabetic women, the distensibility of the common femoral artery did not clearly differ between patients and controls, neither for women nor for men. Thus, the gender difference in changes of arterial distensibility found in elastic arteries was absent or far less obvious in the femoral artery. In conclusion, female gender seems to affect the mechanical properties of elastic, but not of large muscular arteries in type I diabetic patients. Thus, putative gender differences in arterial changes in type I diabetes are to be sought in elastic rather than muscular arteries

A new non-invasive ultrasonic method for simultaneous measurements of longitudinal and radial arterial wall movements: first in vivo trial.

During recent years, the radial movement of the arterial wall has been extensively studied, and measurements of the radial movement are now an important tool in cardiovascular research for characterizing the mechanical properties of the arterial wall. In contrast, the longitudinal movement of vessels has gained little or no attention as it has been presumed that this movement is negligible. With modern high-resolution ultrasound, it can, however, be seen that the intima-media complex of the arterial wall moves not only in the radial direction, but also in the longitudinal direction during pulse-wave propagation. This paper describes a new non-invasive ultrasonic method that is able to measure simultaneously two dimensionally arterial vessel wall movements. The method is demonstrated in a limited in vivo trial. Results from the in vivo trial show that, apart from the well-known radial movement, there is a distinct longitudinal movement in the human common carotid artery with, in this case, the intima-media complex moving substantially as compared with the region of the tunica adventitia. Two-dimensional evaluation of the vessel-wall movements, taking not only the radial movement, but also the longitudinal movement into account, may provide novel information of importance in the evaluation of vessel-wall function

Cardiovascular autonomic neuropathy associated with carotid atherosclerosis in Type 2 diabetic patients.

AimsTo clarify if cardiovascular autonomic neuropathy is associated with carotid artery atherosclerotic plaques in Type 2 diabetic patients. MethodsCardiovascular autonomic nerve function was related to carotid artery ultrasound in 61 Type 2 diabetic patients 5-6 years after diagnosis of diabetes. ResultsCardiovascular autonomic neuropathy [abnormal age corrected expiration/inspiration (E/I) ratio or acceleration index (AI)] was found in 13/61 (21%) patients. Patients with cardiovascular autonomic neuropathy showed increased degree of stenosis in the common carotid artery (24.6 ± 13.2% vs. 14.7 ± 9.2%; P = 0.014) and a tendency towards a higher plaque score (4.0 ± 1.7 vs. 3.2 ± 1.6; P = 0.064). Controlled for age, AI correlated inversely with degree of stenosis (r = -0.39; P = 0.005), plaque score (r = -0.39; P = 0.005), and mean (r = -0.33; P = 0.018) and maximum (r = -0.39; P = 0.004) intima-media thickness in the common carotid artery. In contrast, E/I ratio correlated only slightly with mean intima-media thickness in the common carotid artery (r = -0.28; P = 0.049). ConclusionsCardiovascular autonomic neuropathy was associated with carotid atherosclerosis in Type 2 diabetic patients. Abnormal E/I ratios reflect efferent structural damage to parasympathetic nerves whereas abnormal AI reflects afferent autonomic dysfunction possibly due to impaired baroreceptor sensitivity secondary to carotid atherosclerosis

Arterial wall stiffness in man. On gender differences and abnormalities in insulin dependent diabetes mellitus and alpha1-antitrypsin deficiency.

The mechanical properties of major arteries may reflect early manifestations of vascular disease and are also of interest because they are important for cardiac work. Using echo-tracking sonography and blood pressure measurements, arterial stiffness and diameters were investigated in healthy individuals as well as in patients with insulin dependent diabetes mellitus (IDDM) or alpha1-antitrypsin deficiency (alpha1-AT deficiency). In healthy individuals the stiffness of the abdominal aorta (AO) and the common carotid artery (CCA) increases with age and the diameters increase. These changes are more pronounced in the AO than in the CCA. Further, there are gender differences. This may serve as a background to regional as well as gender differences in the development of vascular disease. In IDDM, stiffness was increased in both the AO and the CCA in women compared to controls. In contrast, there was no difference in stiffness between men with IDDM and controls. Thus, a marked gender-difference in changes of arterial stiffness is found in IDDM. The increased AO stiffness in IDDM women is related to the duration of diabetes. Further, independent of the duration, there is an association between increased AO stiffness and autonomic dysfunction. Increased arterial stiffness in women with IDDM may contribute to the particularly increased risk for cardiovascular complications in diabetic women. To evaluate if alpha1-AT deficiency is a pathogenetic factor in the development of abdominal aortic aneurysm (AAA), the diameter and stiffness of the AO in patients with homozygous alpha1-AT deficiency (PiZZ) were investigated. No difference in the AO diameter compared to controls was found. Men, but not women, had lower AO stiffness than controls. Further, the prevalence of alpha1-AT deficiency (PiZ) in patients with AAA was studied. There was no increase in alpha1-AT deficiency (PiZ) in the patients with AAA compared with the general population. Thus, alpha1-AT deficiency does not seem to be an important pathogenetic factor for the development of AAA

Intra-Observer Variability of Longitudinal Movement and Intramural Shear Strain Measurements of the Arterial Wall using Ultrasound Non-Invasively in vivo

Using a recently developed high-resolution noninvasive ultrasonic method, we recently demonstrated that the intima-media complex of the common carotid artery show a bidirectional multiphasic longitudinal displacement of the same magnitude as the diameter change during the cardiac cycle. The longitudinal movement of the adventitial region was smaller, thus, we identified shear strain and, thus, shear stress, within the arterial wall. The aim of this study was to evaluate the intra-observer variability of measurement of the longitudinal displacement of the intima-media complex and the intramural shear strain of the common carotid artery in vivo using the new ultrasonic method. The evaluation was carried out by comparing two consecutive measurements on the common carotid artery of 20 healthy human subjects. According to the method of Bland Altman, we show that the systematic and random differences for the different phases of movement are acceptable in comparison to the measured displacement and no significant differences between the two measurements could be detected (p > 0.05 for all measured parameters). The coefficient of variation (CV) for measurement of the different phases of movement was ≤16%, including short-term physiologic variations. The higher variability in the measurement of the intramural shear strain (CV = 24%) has several explanations, which are discussed. In conclusion, this study shows that the present first ultrasonic method for high-resolution measurement of the longitudinal movement of the arterial wall is reliable and satisfactory for the further research of the longitudinal movement of the arterial wall in vivo. Further studies on the longitudinal movement of the arterial wall are important for developing an improved understanding of the physiology and the pathophysiology of the cardiovascular system

Response of the carotid artery longitudinal motion to submaximal physical activity in healthy humans-Marked changes already at low workload

The longitudinal motion of the arterial wall, that is, the displacement of the arterial wall along the artery, parallel to blood flow, is still largely unexplored. The magnitude and nature of putative changes in longitudinal motion of the arterial wall in response to physical activity in humans remain unknown. The aim of this study was therefore to study the longitudinal motion of the carotid artery wall during physical activity in healthy humans. Using in-house developed non-invasive ultrasonic methods, the longitudinal motion of the intima-media complex and the diameter changes of the right common carotid artery (CCA) in 40 healthy volunteers (20 volunteers aged 22-35 years; 20 volunteers aged 55-68 years) were assessed at rest and during submaximal supine bicycle exercise. In a subset of the subjects (n = 18) also intramural shear strain were analyzed. The longitudinal motion of the intima-media complex underwent marked changes in response to physical activity, already at low workload; with most evident a marked increase of the first antegrade displacement (p < 0.001) in early systole. Likewise, the corresponding shear strain also increased significantly (p = 0.004). The increase in longitudinal motion showed significant correlation to increase in blood pressure, but not to blood flow velocity or wall shear stress. In conclusion, physical activity markedly influences the longitudinal motion of the carotid artery wall in healthy humans already at low load. A possible "cushioning" function as well as possible implications for the function of the vasa vasorum, endothelium, and smooth muscle cells and extracellular matrix of the media, are discussed

Stiffness and diameter of the common carotid artery and abdominal aorta in women

Vascular disease is differentiated throughout the vascular regions with aorta more prone to dilatation and with peripheral arteries more prone to occlusive disease. In this study, we investigated the diameter and distensibility in the common carotid artery (CCA) and abdominal aorta (AO) in healthy females of varying ages to assess potential differences in the aging process. The diameter and pulsatile diameter change of the CCA and AO in 66 healthy Caucasian females aged 8 to 79 y were examined using an ultrasound phase-locked echo-tracking technique. Blood pressure was obtained by the auscultatory method. Arterial stiffness (beta) was calculated. The diameter of both CCA and AO increases, not only in childhood, but also in adult women. The dilatation in adults (25 to 75 y) seems to be more pronounced in the AO (23%) than in the CCA (11%). Stiffness (beta) is higher in the CCA than AO before 20 y of age (p < 0.05). Stiffness increases with aging in both arterial regions, but the increase is initially somewhat higher in the AO, which means that no differences between the CCA and AO are seen from 25 y onward. In conclusion, this study demonstrates regional differences in diameter change and stiffness in the CCA and AO, and implies that the AO is more prone to age-related changes of the arterial wall than the CCA. These differences, however, are not as marked as previously reported in males

Changes in aortic wall stiffness in men with alpha 1-antitrypsin deficiency

Objectives: To examine the diameter and distensibility of the abdominal aorta in patients with severe α1-antitrypsin deficiency, and to compare the results with those of normal subjects. Material and methods: Abdominal aortic diameter and stiffness (β) was measured using echo-tracking sonography in 19 men (mean age 50, range 25–79) and 17 women (mean age 46, range 26–62) with severe α2-antitrypsin deficiency. The results were compared with those of healthy individuals of corresponding age and gender. Results: There was no significant difference in the abdominal aortic diameter between controls and patients with α1-antitrypsin deficiency when corrected for age, sex and body surface area (men p = 0.20, women p = 0.10). Men with α1-antitrypsin deficiency showed significantly lower stiffness in the abdominal aorta compared to controls (p = 0.025), whereas women did not (p = 0.17). Conclusions: No significant difference in abdominal aortic diameter could be detected in patients with α1-antitrypsin deficiency compared with controls. However, aortic distensibility in men with α1-antitrypsin deficiency is altered. This may reflect early vessel wall abnormality

Does long-term smoking affect aortic stiffness more in women than in men?

Smoking is a well-known risk factor for cardiovascular disease, although understanding of the pathophysiological mechanism is incomplete. The effect of heavy smoking, for more than 20 years and of 20 cigarettes per day, on aortic stiffness was studied in women (n = 23, age range 43-61 years) and men (n = 21, age range 43-61 years) who smoked but were otherwise healthy and compared with a healthy reference population that did not smoke. Aortic stiffness (beta) was calculated from the diameter and the pulsatile diameter change determined non-invasively using an ultrasonic echo-tracking system and blood pressure obtained by the auscultatory method. The results showed that aortic diameter did not differ in smoking males (P = 0.974) or in smoking females (P = 0.361). Aortic stiffness was increased in the female (P = 0.041) but not male smokers (P = 0.222). Systolic, mean and diastolic blood pressure in the men and women who smoked did not differ from those in the healthy reference population. In conclusion, this investigation shows increased aortic stiffness in female but not in male smokers. It indicates that the aorta of women might be more vulnerable to smoking with regard to stiffening and degeneration than the aorta of men