Arterial stiffness: a new cardiovascular risk factor?

Impaired Elasticity of Aorta in Patients with Erectile Dysfunction

OBJECTIVES

The close relationship between the elasticity of the aorta and cardiovascular disease has aroused the interest of investigators in performing studies related to aortic stiffness parameters. We investigated the aortic stiffness parameters in patients with erectile dysfunction (ED) without known cardiovascular disease and diabetes were investigated.

METHODS

The study included 40 men with ED (aged 56 +/- 8 years) according to the Doppler penile ultrasound findings and the five-item version of the International Index of Erectile Function score (group 1) and 25 healthy men (aged 53 +/- 5 years; group 2) underwent fasting serum glucose and lipid level determination. Echocardiography (using a 3.75-MHz transducer) and exercise treadmill test were performed. The diameter change, pulse pressure, aortic strain index, and distensibility index as aortic stiffness parameters were investigated in patients with ED and compared with those of healthy subjects.

RESULTS

The average International Index of Erectile Function-5 score of those with ED (group 1) and the control groups (group 2) was 11.2 and 23.2, respectively. Body mass index, age, fasting serum glucose, and lipid profile were not significantly different between the two groups. All patients had negative results on the exercise stress test; and the echocardiography parameters were similar. The percentage of aortic strain (group 1, 4.64 +/- 2.43 versus group 2, 10.21 +/- 5.13, P = 0.021) and the value of the distensibility index (group 1, 0.21 +/- 0.15 versus group 2, 0.51 +/- 0.20 cm2/dyn/10(-3), P <0.001 were significantly lower in the ED group than were those of the control group.

CONCLUSIONS

The results of our study have shown that the aortic strain index and distensibility index are impaired in patients with ED. This suggests that ED is a generalized vessel disease rather than a disorder peculiar to the penile arteries.

Experimental system for ex vivo measurement of murine aortic stiffness

While vascular stiffness is universally studied using pulse wave velocity, this method overestimates the stiffness of small calibre blood vessels. We have developed and rigorously validated an ex vivo system for measuring stiffness of the mouse aorta. The system consists of a temperature-controlled tissue bath, a pressurization loop and a helium-neon laser micrometer. We harvested thoracic aortas from 8 (n = 56), 11 (n = 6) and 14 (n = 6) week male C57BL/6J mice, mounted them within a tissue chamber and applied an intraluminal pressure waveform while measuring mid vessel outer diameter. Vessel stiffness (E(p), mmHg) was calculated from the pressure-diameter response. Vessels were then stained for endothelial cells, smooth muscle cells, elastin fibres and collagen. The data indicate highly reproducible stiffness measurements in 8 week mice (E(p) = 602.4 +/- 160.2; p = 0.934), age-related stiffening between 11 and 14 week mice (11 week E(p) = 646.9 +/- 62.4, 14 week E(p) = 795.4 +/- 87.5, p = 0.008), and a morphologically intact vessel wall. These results represent the first ex vivo measurements of murine aortic stiffness and illustrate that our methods are feasible and reliable. Since we demonstrate that the system is sensitive to age-related stiffening and does not damage the vessel, this approach is useful for investigating the pathophysiology of vascular disease from biomechanical and histological perspectives.

Vascular adaptations to 8-week cycling training in older men

AIM

Because age-related changes in the large conduit arteries (increased wall thickness, and attenuated arterial compliance and endothelial function) are associated with cardiovascular pathology, prevention is of paramount importance. The effects of endurance training (i.e. walking or cycling) in older humans are assessed in cross-sectional studies, examining the brachial and carotid arteries (supplying non-trained areas). The purpose of this study was to assess the effects of 8-week endurance training in older men on conduit artery characteristics in the trained and non-trained vascular beds.

METHODS

In eight healthy sedentary older men (70 +/- 3 years), characteristics of the large conduit arteries [common femoral (CFA), superficial femoral (SFA), carotid (CA), and brachial artery (BA)] were measured before and after 8-week cycling training. Functional [arterial compliance and flow-mediated dilation (FMD)] and structural (diameter and intima-media thickness) conduit artery properties were measured using echo-Doppler. Peak blood flow, representing structural peripheral adaptations, was measured using venous occlusion plethysmography.

RESULTS

After training, peak leg blood flow was increased (P < 0.01) and baseline diameter and flow were increased in the CFA (P < 0.05). Cycling training enhanced arterial compliance of the SFA (P = 0.03), but did not affect the FMD (P = 0.32) or the intima-media thickness of the SFA. Exercise training did not alter characteristics of the BA or CA.

CONCLUSION

Eight weeks of endurance training in older men altered functional and structural characteristics of the lower extremity vasculature, whereas no changes are reported for the conduit arteries in the non-trained areas (BA or in the CA).

Arterial stiffness following repeated Valsalva maneuvers and resistance exercise in young men

The purpose of this study was to compare arterial stiffness after a bout of resistance exercise (RE) and an experimental condition consisting of repeated Valsalva maneuvers (VMs). Fourteen male participants randomly completed a lower-body, unilateral RE bout and a VM bout designed to alter blood pressure (BP) in a similar pulsatile fashion. Pulse-wave velocity (PWV, measured in metres per second (m.s-1)) was used to measure central and peripheral arterial stiffness and was assessed before and 20 min after each perturbation. Beat-to-beat blood pressure (BP) was assessed during bouts using finger plethysmography. Change in systolic BP, diastolic BP, mean arterial pressure, and pulse pressure were similar during both bouts. Central PWV increased after repeated VMs (7.1 +/- 0.3 m/s to 7.8 +/- 0.3 m/s), but not after RE (7.2 +/- 0.3 m/s to 7.2 +/- 0.3 m/s) (interaction, p = 0.032). There was no change in peripheral PWV after VM (8.9 +/- 0.3 m/s to 9.3 +/- 0.3 m/s) or RE (8.5 +/- 0.2 m/s to 8.4 +/- 0.2 m/s). Arterial stiffness increased after repeated VM. Even though presented with a similar BP load, arterial stiffness did not increase after acute RE. These findings suggest a role for VM in acutely altering arterial properties.

The relationship between aortic stiffness and cardiac function in patients with obstructive sleep apnea, independently from systemic hypertension

OBJECTIVE

We sought to evaluate aortic function and its relationship with left ventricular (LV) function in patients with obstructive sleep apnea syndrome (OSAS), with or without systemic hypertension.

METHODS

A total of 29 patients with OSAS, 28 patients with systemic hypertension without OSAS, and 19 patients having both disorders were chosen as a study group, and 29 participants without these two disorders were taken as the control group; none of the patients had a history of cardiac disease. All of them underwent echocardiography and polysomnography. Aortic strain and distensibility were calculated from the aortic diameters measured by echocardiography and blood pressure obtained by cuff-sphygmomanometer. Cardiac functions were determined using echocardiography comprising standard 2-dimensional and conventional Doppler and Doppler tissue imaging.

RESULTS

Aortic strain (mean +/- SD; 6.1 +/- 2.7% vs 6.4 +/- 2.4%, 4.7 +/- 1.8%, and 13.7 +/- 4.5%, P < .001, respectively) and distensibility (mean +/- SD 2.8 +/- 1.6 vs 2.5 +/- 0.9, 1.7 +/- 0.7, and 6.2 +/- 3.2 10(-6) cm(2) dyn(-1)P < .001, respectively) were significantly decreased in the patient groups (OSAS, hypertensive, and OSAS and hypertensive) compared with the control group. LV long-axis and diastolic functions were also impaired in the study group. There were good correlations between the aortic stiffness and LV function parameters. In a multivariate analysis, aortic strain was the parameter found to be most strongly associated both with the Doppler tissue imaging mean peak early/late diastolic velocity ratio and the LV mitral lateral annular plane systolic excursion.

CONCLUSION

Aortic stiffness parameters (aortic strain and distensibility), LV systolic long-axis function indicators (mitral lateral annular plane systolic excursion, peak systolic myocardial velocity at lateral annulus, peak systolic myocardial velocity at septal annulus), and Doppler tissue imaging-derived LV diastolic indices were found abnormal in patients with OSAS, hypertension, or both. Thus, subclinical cardiac dysfunction has been found in patients with OSAS independent from the systemic hypertension.

Transient elastography using impulsive ultrasound radiation force: a preliminary comparison with surface palpation elastography

The use of impulsive acoustic radiation force for transient strain imaging was investigated and compared with conventional elastography. A series of experiments were performed to evaluate the performances of the technique on gelatine phantoms containing inclusions and to determine a range of applications where radiation force elastography may be useful compared with static elastography. Slip boundaries and cylindrical inclusions of varying elastic modulus were placed in background materials. A focused ultrasound transducer was used to apply localised radiation force to a small volume of tissue mimic (100 mm3) for durations of 8 ms. A conventional real-time ultrasound imaging probe was used to obtain radio- frequency echo signals. The resulting strains were mapped using ultrasound correlation-based methods. The instantaneous strain immediately following cessation of the radiation force was observed at depth within homogeneous gels and within stiff inclusions. The highly localised and transient strain that is produced at depth permits the sensing of variations in tissue elastic properties that are difficult to detect with conventional elastography, due to greater independence from boundary conditions. In particular, radiation force elastograms were more homogeneous in the background and within the inclusions and displayed a superior contrast-transfer-efficiency, particularly for regions that had negative modulus contrast or that were disconnected from the background or the anterior medium by a low friction boundary.

Effect of moderate aerobic exercise on sympatho-vagal balance in Type 2 diabetic patients

AIMS

The purpose of the study was to determine long-term cardiovascular autonomic adaptation to moderate endurance aerobic exercise in people with Type 2 diabetes in order to test the hypothesis of an enhanced vagal drive.

METHODS

We analysed the power spectral density of heart rate cyclic variations at rest, while lying, and while standing in 12 sedentary, non-smoking, Type 2 diabetic individuals. Testing was performed before and after a 6-month, supervised, progressive, aerobic training programme, twice weekly. Heart rate variability was assessed by autoregressive power spectral analysis (PSA); this method allows reliable quantification of low-frequency (LF) and high-frequency (HF) components, which are considered to be under mainly sympathetic and purely parasympathetic control, respectively.

RESULTS

In 10-min electrocardiogram recordings, mean RR intervals values lying and standing were similar before and after physical exercise. Likewise, total heart rate variability, expressed as total power spectral density (PSD), was not altered by exercise. In contrast, on standing, the HF component, expressed in normalized units, was significantly higher (20.1 +/- 4 vs. 30.4 +/- 5, P < 0.01), whereas the LF component was significantly lower (68.1 +/- 7 vs. 49.8 +/- 8, P < 0.01) after exercise; hence, on standing, the LF/HF ratio, reflecting the sympathetic vs. parasympathetic balance, was markedly lower (16.2 +/- 11 vs. 5.2 +/- 3.2, P = 0.003). No significant exercise-related changes in these PSA components were observed on lying.

CONCLUSIONS

A twice-weekly, 6-month, moderate, aerobic exercise programme, without a concomitant weight loss diet, is associated with significant improvements in cardiovascular autonomic function in overweight, non-smoking, Type 2 diabetic individuals.

Reduced Aortic Elasticity and Dilatation Are Associated With Aortic Regurgitation and Left Ventricular Hypertrophy in Nonstenotic Bicuspid Aortic Valve Patients

OBJECTIVES

This study sought to assess elasticity and dimensions of the aorta and their impact on aortic valve competence and left ventricular (LV) function in patients with a nonstenotic bicuspid aortic valve (BAV).

BACKGROUND

Intrinsic pathology of the aortic wall is a possible explanation for reduced aortic elasticity and aortic dilatation in patients with BAVs, even in the absence of a stenotic aortic valve. The relationship between aortic wall elasticity, aortic dimensions, aortic valve competence, and LV function in patients with BAVs has not previously been studied with magnetic resonance imaging.

METHODS

Magnetic resonance imaging was performed in 20 patients with nonstenotic BAVs (mean +/- SD, age 27 +/- 11 years) and 20 matched control patients.

RESULTS

The BAV patients showed reduced aortic elasticity as indicated by increased pulse wave velocity in the aortic arch and descending aorta (5.6 +/- 1.3 m/s vs. 4.5 +/- 1.1 m/s, p = 0.01; and 5.2 +/- 1.8 m/s vs. 4.3 +/- 0.9 m/s, p = 0.03, respectively), and reduced aortic root distensibility (3.1 +/- 1.2 x 10(-3) mm Hg(-1) vs. 5.6 +/- 3.2 x 10(-3) mm Hg(-1), p < 0.01). In addition, BAV patients showed aortic root dilatation as compared with control patients (mean difference 3.6 to 4.2 mm, p < or = 0.04 at all 4 predefined levels). Minor degrees of aortic regurgitation (AR) were present in 11 patients (AR fraction 6 +/- 8% vs. 1 +/- 1%, p < 0.01). The LV ejection fraction was normal (55 +/- 8% vs. 56 +/- 6%, p = 0.61), whereas LV mass was significantly increased in patients (54 +/- 12 g/m2 vs. 46 +/- 12 g/m2, p = 0.04). Dilatation at the level of the aortic annulus (r = 0.45, p = 0.044) and reduced aortic root distensibility (r = 0.37, p = 0.041) correlated with AR fraction. Increased pulse wave velocity in the aortic arch correlated with increased LV mass (r = 0.42, p = 0.041).

CONCLUSIONS

Reduced aortic elasticity and aortic root dilatation were frequently present in patients with nonstenotic BAVs. In addition, reduced aortic wall elasticity was associated with severity of AR and LV hypertrophy.

Noninvasive assessment of preclinical atherosclerosis

Initially considered as a semipermeable barrier separating lumen from vessel wall, the endothelium is now recognised as a complex endocrine organ responsible for a variety of physiological processes vital for vascular homeostasis. These include the regulation of vascular tone, luminal diameter, and blood flow; hemostasis and thrombolysis; platelet and leucocyte vessel-wall interactions; the regulation of vascular permeability; and tissue growth and remodelling. The endothelium modulates arterial stiffness, which precedes overt atherosclerosis and is an independent predictor of cardiovascular events. Unsurprisingly, dysfunction of the endothelium may be considered as an early and potentially reversible step in the process of atherogenesis and numerous methods have been developed to assess endothelial status and large artery stiffness. Methodology includes flow-mediated dilatation of the brachial artery, assessment of coronary flow reserve, carotid intimamedia thickness, pulse wave analysis, pulse wave velocity, and plethysmography. This review outlines the various modalities, indications, and limitations of available methods to assess arterial dysfunction and vascular risk.

Carotid arterial stiffness is marginally higher in the metabolic syndrome and markedly higher in type 2 diabetes mellitus in patients with manifestations of arterial disease

INTRODUCTION

Insulin resistance is generally considered to be of major importance in the pathophysiology of the metabolic syndrome and type 2 diabetes mellitus, both high-risk conditions for cardiovascular complications. Carotid artery stiffness is increasingly recognized as an important predictor of cardiovascular morbidity and mortality. Therefore, in the present study we determined whether the metabolic syndrome (MetSyn) and type 2 diabetes mellitus (DM2) are associated with carotid artery stiffness in patients with already clinical manifestations of arterial disease.

METHODS AND RESULTS

A cross-sectional study in 2105 patients with manifest arterial disease (cerebral, coronary or peripheral artery disease, renal artery stenosis or an aneurysm of the abdominal aorta) was performed. The difference in carotid stiffness between patients with and without MetSyn and with and without DM2 was studied with linear regression analysis. Compared to patients without DM2 (N=1112), patients with DM2 (N=301) had significantly higher arterial stiffness (distension -18.5 (-35.1;-1.9) 95% CI/distensibility -1.8 (-2.2;-1.4) 95% CI). Generally, there was a trend of higher carotid stiffness in patients with MetSyn (N=922) compared to patients without (N=1112) MetSyn (distension -9.6 (-21.5;2.3) 95% CI/distensibility -2.0 (-2.6;-1.4) 95% CI). Excluding the patients with also DM2 (N=230) from the MetSyn-group diminished this relation (distension -5.7 (-18.8;7.4) 95% CI/distensibility -1.1 (-1.6;-0.6) 95% CI). Furthermore, in the population as a whole, carotid artery stiffness increased with increasing number of components of the metabolic syndrome (p=0.08 for distension/p< or =0.001 for distensibility). In addition, this association was not as clear after exclusion of the patients with DM2 from the MetSyn-group (p=0.24 for distension/p<0.001 for distensibility). From all the components of the MetSyn only high blood pressure and high fasting glucose influenced the carotid artery stiffness.

CONCLUSIONS

We concluded that (increasing number of components of) the metabolic syndrome were associated with marginally higher carotid artery stiffness, while type 2 diabetes was associated with a marked increase in carotid artery stiffness, in patients with already clinical manifestations of arterial disease.

Arterial stiffness in 10-year-old children: current and early determinants

It has been suggested that CVD has its origins in early life. An impairment of fetal growth and early postnatal nutrition may have programming effects on cardiovascular physiology. In addition, traditional risk factors for CVD may initiate the atherosclerotic process during childhood. We explored the effect of fat intake, physical activity and lipid profile in childhood, and birth weight, growth during infancy and breast-feeding on arterial stiffness in a cohort study of ninety-three 10-year-old children followed during infancy and re-examined at the age of 10 years. Arterial stiffness in two arterial segments (aorto-radial and aorto-femoral) was measured as pulse wave velocity. Arterial stiffness was inversely associated with physical activity (a regression coefficient in cm/s (95 % CI) of −6·8 (−11·2, −2·4) and −3·9 (−6·9, −0·8) per h of high physical activity/d in the aorto-radial and aorto-femoral segments, respectively). Arterial stiffness was also positively associated with dietary fat energy percentage (3·1 (95 % CI 0·9, 5·2) and 1·8 (95 % CI 0·2, 3·2) per fat energy percentage in the aorto-radial and aorto-femoral segments, respectively) but was not related to body composition, insulin resistance or lipid profile. Arterial stiffness was also positively associated with duration of breast-feeding for the aorto-femoral segment only (2·1 (95 % CI 0·4, 3·7) per month) but was not associated with growth in early life. In conclusion, patterns of physical activity and diet, and history of breast-feeding in infancy, have an influence on the stiffness of the large arteries in children. The long-term effects of this are unknown.

Association of metabolic syndrome with arterial compliance in children and adolescents

The association of metabolic syndrome (MS) with arterial compliance in children and adolescents was explored. 337 subjects (188 men and 149 women) aged 6-18 (10.95 ± 3.01) years, out of "Beijing Child Metabolic Syndrome Study", were divided into three case groups (one component, two components, three & more components of MS) and one control group based on the Cook's MS definition in children and adolescents. Measurements including anthropometry, blood pressure, fasting plasma glucose and insulin, serum lipid profile were done. Homeostasis model assessment for insulin resistance (HOMA-IR) index was calculated for estimating individual insulin resistance. Arterial compliance was measured using digital pulse wave analyzing method from the pulse trace machine (Micro medical, London), and then the stiffness index (SI) was determined. The mean value of SI in MS group was significant higher than that in control group [(7.69 ± 1.63) vs (6.25 ± 0.86) m/s, P<0.01]. With the increase of the clustering of MS components, SI and HOMA-IR were gradually increased. After taking account of gender, age and pubertal development, the partial correlation analysis showed that the amount of components of MS and HOMA-IR were positively correlated with SI (both P values were less than 0.05). The arterial compliance of MS group was significantly lowered in children and adolescents, and with the increase of the clustering of MS components, arterial compliance was gradually decreased. It was suggested that arterial compliance assessment in children and adolescents was important for early prevention of cardiovascular diseases.

Cardiac and systemic hemodynamic characteristics of hypertension and prehypertension in adolescents and young adults: the Strong Heart Study

BACKGROUND

The epidemic of overweight is increasing the prevalence of both prehypertension and early-onset hypertension, but few population-based data exist on their impact on cardiac structure and function in adolescents and young adults.

METHODS AND RESULTS

We analyzed clinical characteristics, hemodynamic parameters, and left ventricular structure and function in 1940 participants, 14 to 39 years of age, in the Strong Heart Study. Hypertension occurred in 294 participants (15%), who were more often men (70% versus 30%), older (age, 31+/-7 versus 25+/-8 years), and more commonly diabetic (23% versus 4.5%; all P<0.001) than their normotensive counterparts. Prehypertension occurred in 675 (35%) of participants with similar trends in gender, age, and diabetes status. After adjustment for covariates, both hypertensive and prehypertensive participants had higher left ventricular wall thickness (0.83 and 0.78 versus 0.72 cm), left ventricular mass (182 and 161 versus 137 g), and relative wall thickness (0.30 and 0.29 versus 0.28 cm) and 3- and 2-fold-higher prevalences of left ventricular hypertrophy than their normotensive counterparts (all P<0.001). Hypertension and prehypertension also were associated with higher mean pulse pressure/stroke volume index (1.24 and 1.15 versus 1.02 mm Hg/mL x m2) and total peripheral resistance index (3027 and 2805 versus 2566 dynes x s x cm(-5) x m2; all P<0.001).

CONCLUSIONS

In a population with high prevalences of obesity and diabetes, hypertension and prehypertension are associated with increases in both cardiac output and peripheral resistance index. Despite the young age of participants with hypertension and prehypertension, they had prognostically adverse preclinical cardiovascular disease, including left ventricular hypertrophy and evidence of increased arterial stiffness.

Insulin Resistance Is Associated with Arterial Stiffness Independent of Obesity in Male Adolescents

To determine the relationship between insulin resistance (IR) and arterial stiffness independent of obesity in male adolescents, we evaluated body fat, lipid parameters, indices of IR (fasting insulin, and the homeostasis model assessment of insulin resistance [HOMA-IR]), indices of insulin sensitivity (IS) (fasting glucose/fasting insulin [GF/IF], and the quantitative insulin sensitivity check index [QUICKI]), and lifestyle parameters in 256 male adolescents. We divided the study group into the following four subgroups based on the median value of HOMA-IR and obesity: non-obese with IS, non-obese with IR, obese with IS, and obese with IR. In order to estimate arterial stiffness, we measured brachial ankle pulse wave velocity (baPWV). Despite having a high body mass index (BMI), obese-IS adolescents showed a significantly lower fasting insulin and baPWV, but had higher IS indices than non-obese-IR adolescents. After an adjustment for age, BMI, waist-to-hip ratio, mean blood pressure, heart rate, total cholesterol level, triglyceride, alanine aminotransferase (ALT) level, physical activity, and television and computer usage, multiple regression models showed that baPWV was independently correlated with IR and IS indices. In conclusion, our results demonstrate an association between IR and baPWV independent of weight, suggesting that IR is a risk factor for the development of early atherosclerosis. Interventions that decrease IR in addition to weight reduction may be necessary to alter the early development of cardiovascular risk.

Aortic Elastic Properties in Patients With Hypertensive Response to Exercise

BACKGROUND

The aim of this study was to evaluate whether there is a relationship between aortic elastic properties in patients with a suggestive response to treadmill exercise testing.

METHODS AND RESULTS

The study group comprised 32 patients suggesting hypertensive response to exercise and 20 patients suggesting normal blood pressure response to treadmill exercise testing. Baseline demographic characteristics were similar in both groups. However, the mean aortic stiffness index of patients suggesting hypertensive response to treadmill exercise testing was significantly higher (4.8+/-1.26 vs 2.36+/-1.09; p=0.001) whereas aortic distensibility was significantly lower (12.82 +/-5.84 vs 22.64+/-14.54; p=0.001) than the control group. The aortic strain of patients with hypertensive response to exercise was lower than the control group (12+/-3% vs 19.2+/-5%, p<0.001). The left ventricular mass (LVM) of these patients was also higher than control group (206.5+/-46.3 vs 134.2+/-19.97; p=0.01). A negative correlation between LVM and distensibility was found (r=-0.64; p=0.001) well as a positive correlation between LVM and aortic stiffness index (r=0.51; p=0.004) in patients suggesting hypertensive response to exercise. Pressure--rate product was also found to be correlated with LVM (r=0.47; p=0.006).

CONCLUSION

Elastic properties of the aorta may be impaired in subjects showing exaggerated blood pressure response to exercise long before clinically manifest hypertension, particularly if the LVM is increased.

Biomechanics of the cardiovascular system: the aorta as an illustratory example

Biomechanics relates the function of a physiological system to its structure. The objective of biomechanics is to deduce the function of a system from its geometry, material properties and boundary conditions based on the balance laws of mechanics (e.g. conservation of mass, momentum and energy). In the present review, we shall outline the general approach of biomechanics. As this is an enormously broad field, we shall consider a detailed biomechanical analysis of the aorta as an illustration. Specifically, we will consider the geometry and material properties of the aorta in conjunction with appropriate boundary conditions to formulate and solve several well-posed boundary value problems. Among other issues, we shall consider the effect of longitudinal pre-stretch and surrounding tissue on the mechanical status of the vessel wall. The solutions of the boundary value problems predict the presence of mechanical homeostasis in the vessel wall. The implications of mechanical homeostasis on growth, remodelling and postnatal development of the aorta are considered.

Elastic properties of aorta in patients with primary hyperparathyroidism

In this study, we aimed to evaluate whether hyperpara thyroidism affects the elastic properties of aorta, calculated as aortic distensibility and aortic stiffness index. Eighteen patients with hyperparathyroidism were enrolled in the study. The control group consisted of 18 healthy subjects with similar baseline characteristics. All subjects underwent echocardiographic examination. Internal aortic root diameters were measured at 3 cm above the aortic valve by the use of two-dimensional guided M-mode transthoracic echocardiography, and arterial blood pressure was measured simultaneously from the brachial artery by sphygmomano metry. Two indexes of the aortic elastic properties were measured which are aortic distensibility and aortic stiffness index. The mean aortic stiffness index of hyperparathyroidic patients was higher (3.04 +/- 1.26 vs. 2.36 +/- 1.09; p = 0.048), and aortic distensibility was lower (15.62 +/- 5.84 vs. 22.64 +/- 14.54; p = 0.035) than the control group. The left ventricular (LV) mass index (242.44 +/- 46.3 vs. 212.8 +/- 43.97; p = 0.048), although it has failed to reach statistical significance, and LV wall stress (57.81 +/- 18.22 vs. 46.57 +/- 15.72; p = 0.08) of these patients was also higher than control group. Hyperparathyroidism increases aortic stiffness index and decreases aortic distensibility of primary hyper parathyroidic patients compared with normal population. The affected aortic elastic properties can be a factor in increased LV mass index and wall stress.

Effect of eucaloric high- and low-sucrose diets with identical macronutrient profile on insulin resistance and vascular risk: a randomized controlled trial

The long-term impact of dietary carbohydrate type, in particular sucrose, on insulin resistance and the development of diabetes and atherosclerosis is not established. Current guidelines for the healthy population advise restriction of sucrose intake. We investigated the effect of high- versus low-sucrose diet (25 vs. 10%, respectively, of total energy intake) in 13 healthy subjects aged 33 +/- 3 years (mean +/- SE), BMI 26.6 +/- 0.9 kg/m(2), in a randomized crossover design with sequential 6-week dietary interventions separated by a 4-week washout. Weight maintenance, eucaloric diets with identical macronutrient profiles and fiber content were designed. All food was weighed and distributed. Insulin action was assessed using a two-step euglycemic clamp; glycemic profiles were assessed by the continuous glucose monitoring system and vascular compliance by pulse-wave analysis. There was no change in weight across the study. Peripheral glucose uptake and suppression of endogenous glucose production were similar after each diet. Glycemic profiles and measures of vascular compliance did not change. A rise in total and LDL cholesterol was observed. In this study, a high-sucrose intake as part of an eucaloric, weight-maintaining diet had no detrimental effect on insulin sensitivity, glycemic profiles, or measures of vascular compliance in healthy nondiabetic subjects.

Lipoprotein (a) as a determinant of arterial stiffness in elderly patients with type 2 diabetes mellitus

BACKGROUND

Lipoprotein (a) [Lp(a)] is known to be a risk factor for atherosclerotic disease. However, the relationship between Lp(a) and arterial stiffness has not been clarified. We investigated whether atherosclerotic risk factors, including serum Lp(a), are associated with aortic stiffness in elderly patients with type 2 diabetes mellitus.

METHODS

Aortic stiffness, evaluated by using aortic pulse wave velocity, and major atherosclerotic risk factors were measured in elderly (> or =65 years) patients with type 2 diabetes mellitus. Relationships between aortic pulse wave velocity, Lp(a) and other atherosclerotic risk factors were analyzed.

RESULTS

Among the atherosclerotic risk factors measured, age, pulse pressure, hemoglobin A1c (HbA1c), uric acid, fibrinogen, sialic acid and Lp(a) showed significant positive correlations with aortic pulse wave velocity. Lp(a) also showed significant positive correlations with pulse pressure, fibrinogen, sialic acid, apolipoprotein B and apolipoprotein B/apolipoprotein A-I ratio. The correlation between Lp(a) and aortic pulse wave velocity was independent of age, sex, blood hemoglobin A1c, uric acid and fibrinogen, history of diabetic nephropathy and therapy with lipid-lowering drugs. Apolipoprotein A-II showed a significant negative correlation with both aortic pulse wave velocity and Lp(a). The median level of Lp(a) in the highest tertile group of subjects divided by aortic pulse wave velocity was significantly higher than the median Lp(a) level in the lowest tertile. The middle and highest tertile groups of subjects divided by aortic pulse wave velocity showed significantly high odds ratios of high Lp(a) levels (> or =30 mg/dl) vs the lowest tertile.

CONCLUSIONS

Lp(a) is an independent determinant of aortic stiffness in elderly patients with type 2 diabetes mellitus.

Impaired aortic elastic properties in young patients with prehypertension

OBJECTIVES

Although hypertension has been shown to be one of the most important predictors of reduced arterial elasticity, there is not enough data about aortic elastic properties in patients with prehypertension. Accordingly, the current study was designated to evaluate aortic elastic features in young patients with prehypertension.

MATERIAL AND METHODS

The study population consisted of 25 newly diagnosed prehypertensive individuals (18 men, mean age=34+/-6 years) and 25 healthy controls (16 men, mean age=33+/-6 years) eligible for the current study. Aortic strain, distensibility index and stiffness index beta were calculated from aortic diameters measured by echocardiography and blood pressures simultaneously measured by sphygmomanometry.

RESULTS

Prehypertensive patients were detected to have significantly lower aortic distensibility and strain indexes than the controls: (5.77+/-1.91 vs. 8.63+/-2.67 cm dynx10, respectively, P<0.001; strain index: 13.81+/-4.50 vs. 17.47+/-4.25%, respectively, P=0.005). Aortic stiffness index beta of the prehypertensive group, however, was significantly higher than that of the control group (3.73+/-1.41 vs. 2.97+/-0.82, P=0.02).

CONCLUSION

Whatever the mechanism, young patients with prehypertension have impaired aortic elasticity compared with healthy controls. This finding has suggested that the development of overt hypertension may be prevented or delayed by using the agents that have the ability to reduce arterial stiffness by regressing and/or preventing functional and structural changes on the arterial wall.

HYPERPARATIROSIS AND CARDIOVASCULAR SYSTEM PATHOLOGY

For many years, hyperparathyroidism, including primary, primarily associated with severe pathology of the osseous system and kidneys, was considered a rare disease. The widespread introduction into the clinical practice of the determination in the blood of calcium, and then parathyroid hormone, and osteodensitometry made it possible to recognize this disease more often and at earlier stages and to treat it more successfully. By now, the specific gravity of mild and asymptomatic forms of hyperparathyroidism has increased from 10-15% in the 1980s to 80%. Conservative management of these forms of hyperparathyroidism requires more thorough research on the prognosis of survival, duration and quality of life, and the risk of developing associated diseases in these patients.

Arterial Wave Reflections Are Associated With Left Ventricular Diastolic Dysfunction in Adamantiades-Behçet's Disease

BACKGROUND

Adamantiades-Behçet's disease (ABD) is characterized by systemic vasculitis. We investigated whether aortic distensibility and arterial wave reflections are linked to left ventricular (LV) diastolic dysfunction in ABD.

METHODS AND RESULTS

Eighty-two patients and 40 controls with similar atherosclerotic risk factors were examined by applanation tonometry of the radial artery (SphygmoCor) and echocardiography. Augmentation index (AI%) and arrival time (Deltat, ms) of reflected arterial waves as well as aortic distensibility (AoD) assessed by echocardiography were estimated. Doppler diastolic abnormalities were defined as proposed by the European Study Group on Diastolic Heart Failure by measurement of E/A ratio, isovolumic relaxation time, deceleration time, and flow propagation velocity. Patients had impaired central augmentation index (CAI), Deltat, and AoD compared with controls (P > .05). After adjusting for age, atherosclerotic risk factors, left ventricular mass, and medication the odds-ratio of AoD and CAI for left ventricular diastolic dysfunction was 0.664 (95%CI 0.449-0.982), P = .04, and 1.073 (95% CI 1.014-1.140), P = .001, respectively. The addition of CAI to the multivariable model including AoD significantly increased the power of the model for prediction of left ventricular diastolic dysfunction (-2 Log likelihood change = 18.8, P for change > .01).

CONCLUSION

Augmentation index has a complementary value to aortic distensibility in the assessment of left ventricular diastolic dysfunction in ABD.

Monitoring vascular health beyond blood pressure

It is well recognized that vascular changes, including atherosclerosis, begin early in life as a silent, asymptomatic disease process and are associated with cardiovascular (CV) risk factors. Importantly, CV risk factors persist or track from childhood to adulthood and are predictive of CV disease risk in adults. Evaluation of arterial stiffness and its predictors may help identify asymptomatic individuals at risk, before blood pressure is elevated above an "arbitrary" level that we currently identify as hypertension. Currently, measurements of arterial stiffness are being used in the research setting and also as part of cardiovascular risk prediction clinics. As the various techniques become more widely available, it is conceivable that the measurement of arterial stiffness could become an important part of the routine assessment of patients in daily practice, as a supplement to blood pressure measurement. Measurement of arterial stiffness will not only be helpful in the detection of early vascular disease but also will be a tool in the follow-up monitoring of strategies aimed at preventing hypertension or reducing further progression of vascular disease before blood pressure elevation can be detected.

Impaired vasoreactivity in bodybuilders using androgenic anabolic steroids

BACKGROUND

Anabolic androgenic steroids are used by some bodybuilders to enhance performance. While the cardiovascular implications of supraphysiological androgen levels requires further clarification, use is associated with sudden death, left ventricular hypertrophy, thrombo-embolism and cerebro-vascular events.

MATERIALS AND METHODS

To further understand the effect of androgenic anabolic steroid abuse on vascular function, this study assessed vascular stiffness (pulse-wave analysis) and cardiovascular risk factors in 28 male, bodybuilding subjects, of whom ten were actively receiving anabolic agents (group A; 26.4 +/- 7.2 years) and eight had undergone a 3-month "wash-out" period (group B; 32.1 +/- 7.1 years). The remaining ten bodybuilding subjects (group C; 24.4 +/- 4.4 years) denied any past use of anabolic steroids or other performance enhancing drugs. Comparisons were made with ten sedentary male controls (group D, 29.3 +/- 4.7 years).

RESULTS

Endothelial independent dilatation in response to glycerol trinitrate was significantly impaired in the group currently using anabolic steroids (group A) compared with the other three groups [A (5.63 +/- 3.24%) versus; B (11.10 +/- 4.91%), C (17.88 +/- 9.2%) and D (14.46 +/- 3.9%), P < 0.0005, respectively], whereas no significant differences in endothelial-dependent dilatation were detected between the groups [A (5.0 +/- 3.0%), B (7.4 +/- 3.4%), C (9.6 +/- 4.5%) and D (8.2 +/- 3.3%), P < 0.059, respectively].

CONCLUSIONS

Previous studies described a decline in vascular reactivity occurring in bodybuilding subjects which is independent of anabolic steroid use and may result from smooth muscle hypertrophy with increased vascular stiffness. This study revealed impaired vascular reactivity associated with anabolic agents and that improvement in vascular function may occur following their discontinuation.

Temocapril, an Angiotensin converting enzyme inhibitor, ameliorates age-related increase in carotid arterial stiffness in normotensive subjects

BACKGROUND/AIMS

Oxidative stress plays an important role in vascular ageing. The close relationship of the renin-angiotensin system with mechanisms of oxidative stress suggests its possible involvement in the deleterious effects of ageing. The present study was designed to investigate whether inhibition of the renin-angiotensin system improves the age-related increase in arterial stiffness.

METHODS

Normotensive elderly subjects in a geriatric nursing home (n = 24; male/female = 7/17; 86 +/- 9 years, mean +/- SD) were randomly assigned to receive either an angiotensin converting enzyme inhibitor, temocapril (n = 12, 1 mg daily) or nothing (n = 12). Carot id arterial stiffness parameter beta and circulating levels of malondialdehyde-modified low-density lipoprotein were measured before and 6 months after randomization.

RESULTS

Temocapril decreased beta (from 7.0 +/- 1.0 to 4.9 +/- 0.9, p < 0.05) and malondialdehyde-modified low-density lipoprotein levels (from 73.2 +/- 19.9 to 61.3 +/- 18.4 U/l, p < 0.05) without changing the blood pressure. The changes in beta and malondialdehyde-modified low-density lipoprotein levels were significantly correlated (rho = 0.600, p < 0.05).

CONCLUSION

These results suggest that temocapril ameliorates the age-related increase in carotid arterial stiffness in healthy, normotensive elderly subjects.

Polymorphism in Endothelin-Related Genes Limits Exercise-Induced Decreases in Arterial Stiffness in Older Subjects

Increase in arterial stiffness is associated with aging, which is improved by regular exercise. Endothelin (ET) system has crucial roles in regulating vascular tone and in the progression of atherosclerosis. We hypothesized that molecular variations (ie, gene polymorphisms) in ET-related gene might affect exercise-induced improvement in arterial stiffness with age in human subjects. The present study provides a cross-sectional investigation of 191 healthy middle-aged and older (65±1 years) human subjects to clarify the relationship between the regular exercise-induced improvement of arterial stiffness and the gene polymorphisms of ET converting enzyme (ECE)-1, ECE-2, ET-A receptor (ET-A), and ET-B receptor (ET-B). The study subjects were divided into active and inactive groups based on the median value (186 kcal/d) of energy expenditure. Brachial-ankle arterial pulse wave velocity (baPWV) was used to evaluate arterial stiffness. All individuals were genotyped for 4 different polymorphisms of the ET system: 2013(+289)A/G in intron 17 of ECE-1, 669(+17)T/C in intron 5 of ECE-2, 958A/G in exon 6 of ET-A, and 831A/G in exon 4 of ET-B. The baseline baPWV was significantly lower in the active group without any change in blood pressure. Polymorphisms in ECE-1 influenced basal blood pressure. Polymorphisms in ECE-1 and ECE-2 had no effect on baPWV between active and inactive groups. However, polymorphisms in both ET-A and ET-B affected baPWV in the 2 groups. The present results suggest that differences in ET-A and ET-B polymorphisms may influence the response of the vascular wall to exercise whereas ECE-1 polymorphisms may affect basal blood pressure.

Different Effects of Atherogenic Lipoproteins and Blood Pressure on Arterial Structure and Function: The Bogalusa Heart Study

Differential impact of non-high-density lipoprotein cholesterol (total cholesterol minus high-density lipoprotein cholesterol) and blood pressure on arterial wall thickness and stiffness was examined in 900 black and white adults aged 24-43 years. Blacks compared with whites had greater values of pulse wave velocity (5.4 m/sec vs. 5.2 m/sec; p<0.01) and carotid artery intima-media thickness (0.83 mm vs. 0.80 mm; p<0.01). Non-high-density lipoprotein cholesterol was significantly associated with carotid intima-media thickness (standardized regression coefficient [b]=0.21; p<0.01), but not with pulse wave velocity (b=0.03; p=0.37), after adjusting for race, sex, age, body mass index, insulin, glucose, and smoking. Systolic blood pressure was associated significantly stronger with pulse wave velocity (b=0.36; p<0.01) than with carotid intima-media thickness (b=0.15; p<0.01). No race difference in these relationships was found. The results of this study indicate that atherogenic lipoproteins and blood pressure may play different roles in the development of arterial wall stiffness and atherosclerosis.

Correlates of vascular structure and function measures in asymptomatic young adults: the Bogalusa Heart Study

BACKGROUND

Adverse changes in arterial structure and function, independent predictors of cardiovascular (CV) disease morbidity and mortality, are known to be associated with CV risk factors, especially in middle-aged and older adults. Although non-invasive studies in this regard are beginning to emerge in a younger age population, information is lacking on the correlates of measures of vascular structure and function obtained simultaneously by different non-invasive methods.

METHODS

In 518 black and white subjects (72% white, 44% male) aged 27-43 years, vascular structure and function were measured in terms of (1) carotid artery intima-media thickness (IMT), (2) aorta-femoral pulse wave velocity (af-PWV), and (3) pulsatile arterial function in terms of large (C1) and small (C2) artery compliances.

RESULTS

Blacks versus whites and males versus females had higher carotid IMT; blacks versus whites higher af-PWV; and blacks versus whites and females versus males lower C1 and C2. In a multivariate regression model, significant predictors in the order of entry into the model were systolic blood pressure, male gender, age, cigarette smoking, and LDL cholesterol for carotid IMT (R(2)=0.189); systolic blood pressure, homeostasis model assessment of insulin resistance (HOMA-IR), cigarette smoking, and age for af-PWV (R(2)=0.200); systolic blood pressure, female gender, and HOMA-IR for C1 (R(2)=0.258); and systolic blood pressure, female gender, age, diastolic blood pressure, cigarette smoking, triglycerides, and black race for C2 (R(2)=0.394).

CONCLUSION

In asymptomatic young adults, CV risk factors influence adversely measures of both structure and function of the vasculature to varying degrees, with small artery compliance showing maximum variance. As part of preventive cardiology, assessment of structure/function measures of the vasculature by simple non-invasive methods may be helpful in identifying early vascular damage in a high-risk young population group.

Elastography for breast cancer diagnosis using radiation force: system development and performance evaluation

The use of impulsive acoustic radiation force for strain imaging was investigated. A focused ultrasound transducer was used to apply localized radiation force to a small volume of tissue mimic (100 mm3) for durations of 8 ms. A conventional real-time ultrasound imaging probe was used to obtain echo signals. The resulting strains were mapped using ultrasound correlation-based methods. The instantaneous strain immediately following cessation of the radiation force was observed at depth within homogeneous gels and within stiff inclusions, and was seen to vary approximately linearly with Young's modulus of the material. The highly localized and transient strain that is produced may permit the sensing of variations in tissue elastic properties that are difficult to detect with conventional elastography because of greater independence from boundary conditions. For example, the characteristic, bi-directional, high strain artefacts attributable to stress concentration, often seen with static elastography at tissue-inclusion interfaces, do not appear using the transient radiation force strain imaging technique.

Trait Anger and Arterial Stiffness: Results From the Atherosclerosis Risk in Communities (ARIC) Study

The cross-sectional association between trait anger and stiffness of the left common carotid artery was examined in 10,285 black or white men or women, 48-67 years of age, from the Atherosclerosis Risk in Communities (ARIC) study cohort. Trait anger was assessed using the 10-item Spielberger Trait Anger Scale. Arterial stiffness was assessed by pulsatile arterial diameter change (PADC) derived from echo-tracking ultrasound methods; the smaller the PADC, the stiffer the common carotid artery. In men, trait anger was significantly associated with PADC, independent of the established cardiovascular disease risk factors (p=0.04). PADC decreased from the first (lowest anger group) to the second quintile of anger, but there was no progressive decrease thereafter. Also observed was a 13-microm (95% confidence interval [CI], 1-25) difference in the magnitude of PADC from the lowest to the uppermost quintile of anger (PADC [standard error], 421 [4] microm vs. 408 [5] microm). In women, the association was marginally significant (p=0.07). The low-high difference in the magnitude of PADC (PADC [standard error], 397 [3] microm vs. 406 [4] microm) was inverse (-9 microm 95% CI, -19 to 2). Conclusions indicate that very high trait anger is associated with arterial stiffness in men.

Analysis of contrast in images generated with transient acoustic radiation force

Several mechanical imaging methods are under investigation that use focused ultrasound (US) as a source of mechanical excitation. Images are then generated of the tissue response to this localized excitation. One such method, acoustic radiation force impulse (ARFI) imaging, utilizes a single US transducer on a commercial US system to transmit brief, high-energy, focused acoustic pulses to generate radiation force in tissue and correlation-based US methods to detect the resulting tissue displacements. Local displacements reflect relative mechanical properties of tissue. The resolution of these images is comparable with that of conventional B-mode imaging. The response of tissue to focused radiation force excitation is complex and depends upon tissue geometry, forcing function geometry (i.e., region of excitation, or ROE) and tissue mechanical and acoustic properties. Finite element method (FEM) simulations using an experimentally validated model and phantom experiments have been performed using varying systems, system configurations and tissue-mimicking phantoms to determine their impact on image quality. Image quality is assessed by lesion contrast. Due to the dynamic nature of ARFI excitation, lesion contrast is temporally-dependent. Contrast of spherical inclusions is highest immediately after force cessation, decreases with time postforce and then reverses, due to shear wave interaction with internal boundaries, differences in shear modulus between lesions and background and inertial effects. In images generated immediately after force cessation, contrast does not vary with applied force, increases with lesion stiffness and increases as the ROE size decreases relative to the size of the structure being imaged. These studies indicate that improved contrast in radiation force-generated images will be achieved as ROE size decreases; however, frame rate and thermal considerations present trade-offs with small ROE size.

Increased aortic stiffness in patients with coronary artery ectasia

OBJECTIVE

Alterations in aortic stiffness may reflect the elastic properties of the larger arteries. In many diseases, aortic elastic properties have been investigated to show whether the larger arteries are involved. The elastic properties of aorta in patients with coronary artery ectasia, however, have not been studied yet. We aimed to investigate aortic stiffness parameters in patients with coronary artery ectasia and to compare patients with coronary artery ectasia and coronary artery disease with the control group.

METHOD

Thirty-three patients with coronary artery ectasia, 31 patients with coronary artery disease and 30 patients with angiographically normal coronary arteries were included in this study. Aortic diameters were measured on the M-mode tracing obtained at a level 3 cm beyond the aortic valve at parasternal long-axis view. Aortic diameter change, aortic strain, aortic distensibility and stiffness parameters were measured as aortic stiffness parameters.

RESULTS

Aortic diameter changes were fewer in the coronary artery ectasia and coronary artery disease group than in the control group (0.4 +/- 0.1 and 0.3 +/- 0.1 vs. 0.8 +/- 0.2; P < 0.001). Aortic distensibility and aortic strain were significantly lower in patients with coronary artery ectasia and coronary artery disease than in the controls (for aortic distensibility P < 0.001 and for aortic strain P < 0.001, < 0.001, respectively). In contrast, a significantly higher aortic stiffness index was observed in patients with coronary artery ectasia and coronary artery disease than in the control group (14.2+/-2.6 and 18.1 +/- 2.9 vs. 5.9 +/- 1.8; P < 0.001, respectively).

CONCLUSIONS

The impairment in aortic elastic properties in patients with coronary artery ectasia indicates that this disease is a generalized disease rather than a localized disease of the coronary arteries.

Postmenopausal oral estrogen therapy and blood pressure in normotensive and hypertensive subjects: the Estrogen in the Prevention of Atherosclerosis Trial

OBJECTIVE

To determine if 17beta-estradiol increases blood pressure in postmenopausal women.

DESIGN

A total of 222 healthy postmenopausal women were randomly assigned to either 1 mg micronized 17beta-estradiol daily or placebo for 2 years. Blood pressure measurements were obtained every other month and common carotid artery intima-media thickness measured every 6 months. Statistical analyses comparing longitudinal changes in systolic and diastolic blood pressure between treatment groups used a mixed general linear model including interaction terms to evaluate variations by age or estradiol level.

RESULTS

Both placebo and estradiol groups showed small declines in systolic and diastolic blood pressure during the trial among the normotensive subjects and subjects on antihypertensive medications. However, the decline did not differ significantly between the groups. Treatment effects on systolic blood pressure differed significantly by the age of the subject (interaction P value = 0.04) with younger women on estradiol showing on average a rise in systolic blood pressure, and older women a decline. The association between serum estradiol level and systolic blood pressure showed a similar modification with age (P = 0.03). Changes in systolic blood pressure in women on estradiol were positively correlated with intima-media thickness progression (P = 0.03).

CONCLUSIONS

Overall, 17beta-estradiol did not influence changes in blood pressure in normotensive or hypertensive women. The effect of 17beta-estradiol treatment on systolic blood pressure may be influenced by a woman's age. Estradiol may increase systolic blood pressure in younger postmenopausal women, while having the opposite effect in older postmenopausal women.

Aortic Stiffness and Aerobic Exercise: Mechanistic Insight from Microarray Analyses

INTRODUCTION/PURPOSE

Regular aerobic exercise reduces aortic stiffness. However, the mechanisms by which chronic exercise lowers arterial stiffness are not known. To determine the molecular mechanisms of these changes, the alteration of gene expression in the aorta by aerobic exercise training was measured with the microarray technique.

METHODS/RESULTS

The differences in expression levels of 3800 genes in the abdominal aorta of sedentary control rats (8 wk old) and exercise-trained rats (8 wk old, treadmill running for 4 wk) were compared by the microarray analysis. Aortic pulse wave velocity (PWV) was lower and systemic arterial compliance was higher (both P < 0.05) in the exercise-trained group than in the control group. Of the 323 genes that displayed differential expression (upregulation of 206 genes and downregulation of 117 genes), a total of 29 genes (24 upregulated and 5 downregulated genes) were identified as potential candidate genes that may be involved in vasodilation and arterial destiffening. Using real-time quantitative polymerase chain reaction, we confirmed the results of microarray analysis that prostaglandin EP2 receptor (PGE-EP2R), prostaglandin EP4 receptor (PGE-EP4R), C-type natriuretic peptide (CNP), and endothelial nitric oxide synthase (eNOS) genes were differentially expressed. Furthermore, there were modest correlations between arterial stiffness and levels of these factors. Differential expression of eNOS gene was further verified at protein level by using Western blot analysis.

CONCLUSION

These results suggest that exercise training induces the altered expression in several genes including prostaglandin, CNP, and nitric oxide in the aorta and that these molecular changes (particularly eNOS as its protein expression was altered) may contribute, at least in part, to the beneficial effect of exercise training on aortic stiffness.

Tumour necrosis factor antagonists improve disease activity but not arterial stiffness in rheumatoid arthritis

OBJECTIVES

Systemic inflammation may play an important role in the accelerated atherosclerosis and increased cardiovascular mortality of rheumatoid arthritis (RA). Atorvastatin reduced arterial stiffness in RA patients after only 6 weeks, an effect that may be partially mediated by the immunomodulatory effects of this drug. Suppression of inflammation with tumour necrosis factor (TNF) antagonists may therefore also improve vascular function in RA; however, TNF antagonists have also been shown to cause or exacerbate congestive heart failure in patients with RA and heart failure. The aim of the present study was to examine the effect of treatment with TNF antagonists on arterial stiffness in RA patients with active disease.

METHODS

Fourteen RA patients (age 55.1 +/- 3.8 yr; disease duration 7.9 +/- 1.3 yr) with high disease activity [disease activity score (DAS28) 7.1 +/- 0.3] commencing treatment with TNF antagonists for the first time were studied. Clinical status and arterial stiffness were measured before and after 6 weeks of TNF antagonist therapy (etanercept, adalimumab or infliximab).

RESULTS

Arterial stiffness did not change during the study period (the mean augmentation index was 29.1 +/- 2.2% at baseline vs 30.1 +/- 1.8% at week 6; P = 0.504). The DAS28 improved significantly from 7.1 +/- 0.3 to 4.3 +/- 0.4 (P < 0.0001). The erythrocyte sedimentation rate and C-reactive protein [median (range)] were reduced from 44 (12-85) to 15 (3-82) mm/h (P = 0.02) and from 34 (3-95) to 10 (2-61) mg/l (P = 0.007), respectively.

CONCLUSIONS

Despite significant reductions in synovitis and inflammatory markers in these RA patients, arterial stiffness was not improved by 6 weeks of treatment with TNF antagonists. This result is of relevance given recent reports of potential adverse cardiovascular effects of TNF antagonists in some RA patients.

Walking may be related to less vascular stiffness in the Activity Counseling Trial (ACT)

BACKGROUND

The ACT was a clinical trial of various patient education and counseling interventions to increase physical activity in sedentary primary care populations. It provided the opportunity to measure the effect of increasing physical activity on aortic pulse wave velocity (APWV), a measure of vascular stiffness, in a relatively healthy middle-aged population. The effects of the interventions, as well as the impact of walking and correlates such as older age and maximal oxygen uptake (VO2max), on APWV were assessed.

METHODS

The participants in this study were a subset of the 874 persons recruited for the ACT. Information about self-reported physical activity and disease status was collected at baseline (464 persons), 6-month (528 persons), and 24-month (555 persons) intervals. Physiological measures included APWV, systolic blood pressure, and other correlates.

RESULTS

In multivariate analyses, the various treatment arms did not have a significant effect on APWV. However, walking in hours per day was associated with slower APWV times or less stiffness (P = .03). This was significant for women and consistent but not significant for men. In addition, age, clinic site, race, systolic blood pressure, and VO2max were independently associated with APWV.

CONCLUSIONS

Increased walking frequency over a 24-month period was predictive of reduced vascular stiffness in ACT. The more significant result for walking frequency in women than in men might be caused by the presence of a low Vo2max or physical activity threshold for an effect of walking on APWV, which most women achieved but most men had surpassed at the start of the study. Although needing confirmation because this was a secondary analysis, modest physical activity may have a beneficial effect on large vessel structure.

Green coffee bean extract improves human vasoreactivity

Our previous study revealed the antihypertensive effects of green coffee bean extract (GCE) ingestion in spontaneously hypertensive rats. We suggested that this antihypertensive action was due to the fact that GCE contains chlorogenic acid (CQA) as a major phenolic compound, and CQA in turn contains ferulic acid as a metabolic component that acts on nitric oxide (NO) derived from the vascular endothelium. In this study, the effects of GCE on blood vessels were evaluated in healthy males. The subjects were 20 healthy males with reduced vasodilation responses measured by strain gauge plethysmograms (SPG) to ischemic reactive hyperemia. Of the 20 subjects, 10 (mean age, 37.2 years) ingested a test drink containing GCE (CQA: 140 mg/day), and the other 10 (mean age, 34.8 years) ingested a placebo drink for 4 months. During the ingestion period, SPG, pulse wave velocity (PWV), and serum biochemical parameters were measured, and acceleration plethysmograms (APG) were taken. The reactive hyperemia ratio (RHR) in the test drink group began to increase after ingestion for 1 month and was significantly higher (p <0.05) than that in the placebo group after ingestion for 3 months and 4 months. In addition, after ingestion for 4 months, the test drink group showed a significant decrease (p <0.01) in the plasma total homocysteine level compared with the pre-ingestion level. However, there were no significant differences in PWV or APG between the test drink group and the placebo drink group. The improvement in RHR after ingestion of a drink containing GCE suggested an improvement in vasoreactivity by this component.

Basal NO Locally Modulates Human Iliac Artery Function In Vivo

We demonstrated previously that endogenous NO influences large-artery distensibility in the ovine hindlimb. However, the role of basal NO in larger human conduit arteries is controversial. The aim of this study was to investigate whether basal production of NO, acting locally, influences iliac artery distensibility in humans. Distensibility was assessed by intra-arterial measurement of the pulse wave velocity. Eighteen subjects, free of significant coronary or iliac artery disease, were studied after diagnostic cardiac catheterization. Simultaneous pressure waveforms were recorded with a high-fidelity dual-pressure sensing catheter, placed in the common iliac artery during intra-arterial infusion of saline (baseline), glyceryl trinitrate (4 nmol/min), or N G -monomethyl- l -arginine (8 and 16 μmol/min). Drugs were infused proximally, via the catheter to perfuse the segment of artery under study, or distally, via the sheath, to control for any reflex changes in flow or sympathetic activation. Velocity was calculated using the foot-to-foot methodology. Six subjects received glyceryl trinitrate and 12 N G -monomethyl- l -arginine. There was no change in velocity after infusion of glyceryl trinitrate or N G -monomethyl- l -arginine via the sheath. However, infusion of glyceryl trinitrate via the catheter significantly reduced velocity by 31.43±5.80% (mean±SEM; P <0.01; P =0.02 for comparison). Likewise, infusion of the highest dose of N G -monomethyl- l -arginine via the catheter significantly increased velocity by 27.25±8.20% ( P =0.001; P =0.02 for comparison). Importantly, there was no change in mean arterial blood pressure throughout the studies. These data indicate that under resting conditions, local NO production modulates human iliac artery distensibility and that exogenous NO increases arterial distensibility.

The effects of body-weight supported treadmill training on cardiovascular regulation in individuals with motor-complete SCI

STUDY DESIGN

Four-month longitudinal within-subject exercise training study.

OBJECTIVE

Although body-weight supported treadmill training (BWSTT) has not shown promise as a means of improving ambulation in individuals with motor-complete spinal cord injury (SCI), it may still improve cardiovascular health and function in this population. The purpose of this study was to (i) investigate the effects of BWSTT on peripheral muscular and elastic artery dimension and function and measures of heart rate variability (HRV) and blood pressure variability (BPV) in individuals with motor-complete SCI, and (ii) to make a preliminary examination of what factors may predict favourable cardiovascular outcomes following BWSTT in this population.

SETTING

Centre for Health Promotion and Rehabilitation, McMaster University, Hamilton, Ontario, Canada.

METHODS

Six individuals (four male, two female; age 37.7+/-15.4 years) with chronic SCI (C4-T12; ASIA A-B; 7.6+/-9.4 years post-injury) were included in the present investigation. Doppler ultrasound was used to determine femoral (exercising; muscular), carotid (elastic) and brachial (non-exercising control; muscular) artery dimension and function before and after 4 months of BWSTT. Continuous heart rate and blood pressure were also recorded before and after 4-months of BWSTT to determine frequency domain measures of HRV and BPV; clinically valuable indices of neurocardiac and neurovascular control, respectively.

RESULTS

Two-way ANOVA (vessel x time) revealed no exercise-induced change in femoral or carotid artery cross-sectional area, blood flow or resistance and no change in carotid artery compliance following the 4 months of BWSTT compared to the non-exercising control brachial artery. However, there was a significant exercise-induced increase in femoral artery compliance. There were no exercise-induced changes in HRV or BPV when all participants were considered together. However, the results suggest that the subgroup of individuals who had a substantial heart rate response to BWSTT (n=3), experienced exercise-training induced changes in HRV reflective of a relative shift toward cardiac vagal predominance and reductions in BPV.

CONCLUSIONS

BWSTT may cause an increase in femoral artery compliance in individuals with motor-complete SCI and therefore, should be encouraged as a means of improving cardiovascular health in this population. BWSTT may also cause modest improvements in measures of HRV and BPV in a select subgroup of individuals who respond to ambulation with moderate to large increases in HR. In the present study, factors associated with a substantial HR response to BWSTT were a propensity to orthostatic intolerance and muscular spasticity.

The relationship between pulse wave velocity and indexes of collagen synthesis in hypertensive patients, according to the level of systolic blood pressure

Vascular stiffening, a process responsible for the development of isolated systolic hypertension, depends on dysregulation of collagen-elastine production and arrangement, yet it is not known whether the effect is uniform throughout wide blood pressure (BP) range. To check whether arterial stiffness is similarly related to increased fibrotic remodelling, in patients with systolic blood pressure (SBP) above and below 160 mmHg. Consecutive peri- and postmenopausal female outpatients treated for hypertension and free from other disorders interfering with fibrotic processes, had their BP, pulse wave velocity (PWV), and collagen (N-terminal procollagen type III propeptide (PIIINP); C-terminal procollagen type I propeptide-(PICP)) measured. The average age of 100 women was 71.8+/-10.5 years, BP was 145/83+/-25/15 mmHg, pulse pressure 63+/-17 mmHg, and mean blood pressure (MBP) 104+/-17 mmHg. PWV was 12.9+/-3.6 m/s and was significantly higher among 30 patients with SBP of > or =160 mmHg. PIIINP averaged 4.6+/-1.6 ng/ml and PICP 142.2+/-47.0 ng/ml. In the low SBP (<160 mmHg) group there was no relationship between PWV and collagen concentrations. However, in the > or =160 mmHg group there was significant correlation between PWV and PIIINP concentration. The relationship held significant after adjustment for age, and BP components. Our result can help explaining the results of recent intervention trials where older patients tended to benefit more from potentially antifibrotic drugs (ACE-I), whereas those with compliant arteries tend to benefit from diuretics.

Systemic associations of retinal microvascular signs: a review of recent population-based studies

Retinal microvascular signs, such as generalized retinal arteriolar narrowing, focal arteriolar narrowing, arteriovenous nicking and retinal haemorrhages, microaneurysms and cotton wool spots, are common fundus findings in the general population, even in individuals without hypertension or diabetes. Recent population-based studies have provided new insights into the systemic associations and clinical significance of these retinal signs. Studies show that these retinal microvascular signs are strongly associated with elevated blood pressure (BP). Generalized retinal arteriolar narrowing may be associated with markers of inflammation and risk of diabetes and hypertension. Retinal haemorrhages, microaneurysms and cotton wool spots are associated with risk of subclinical and clinical stroke, cognitive impairment, renal dysfunction and cardiovascular mortality, independent of BP and cardiovascular risk factors. A consistent pattern of association between retinal microvascular signs and ischaemic heart disease has not been demonstrated. This suggests that patients with some retinopathy signs (retinal haemorrhages, microaneurysms and cotton wool spots) may benefit from a careful systemic evaluation and, if supported by further research, appropriate risk reduction therapy.

Hypertensive retinopathy: there's more than meets the eye

Hypertension is associated with increased cardiovascular risk, leading to systemic end-organ damage, including retinopathy. However, the recent European Society of Hypertension-European Society of Cardiology and World Health Organization-International Society of Hypertension 2003 guidelines propose new prognostic indications for the classification of hypertensive retinopathy. In particular, grades I and II are no longer included among signs of end-organ damage, and only grades III and IV are retained as associated clinical conditions for the stratification of global cardiovascular risk. This review article will focus on the wider implications of clinical markers of microvascular damage in the retina, with specific reference to hypertension and end-organ damage. Early recognition of retinal changes remains an important step in the risk stratification of hypertensive patients.

Effect of aging on carotid artery stiffness and baroreflex sensitivity during head-out water immersion in man

To examine the possible age-related blood pressure (BP) deregulation in response to central hypervolemia, we measured spontaneous baroreflex sensitivity (SBRS), carotid arterial compliance (CC), and R-R interval coefficient of variation (RRICV) during basal and thermoneutral resting head-out-of-water immersion (HOWI) in 7 young (YG = 24.0 +/- 0.8 years) and 6 middle-aged/older (OL = 59.3 +/- 1.3 years) healthy men. Compared with basal conditions (YG = 19.6 +/- 4.0 vs OL = 6.1 +/- 1.5 ms/mmHg, P < 0.05), SBRS remained higher in YG than OL during rest HOWI (YG = 23.6 +/- 6.6 vs OL = 9.3 +/- 2.1 ms/mmHg, P < 0.05). The RRICV was significantly different between groups (YG = 6.5 +/- 1.4 vs OL = 2.8 +/- 0.4%, P < 0.05) under HOWI. The OL group had no increase in CC, but a significant increase in systolic BP (basal = 115.3 +/- 4.4 vs water = 129.3 +/- 5.3 mmHg, P < 0.05) under HOWI. In contrast, the YG group had a significant increase in CC (basal = 0.16 +/- 0.01 vs water = 0.17 +/- 0.02 mm(2)/mmHg, P < 0.05) with no changes in systolic BP. SBRS was positively related to CC (r = 0.58, P < 0.05 for basal vs r = 0.62, P < 0.05 for water). Our data suggest that age-related vagal dysfunction and reduced CC may be associated with SBRS differences between YG and OL groups, and with BP elevation during HOWI in healthy older men.

Effect of hormone therapy on the elastic properties of the arteries in healthy postmenopausal women

The aim of the study was to assess the effect of continuous hormone therapy (HT) for 1 yr on pulse wave analysis and central aortic pressure in healthy postmenopausal women. Sixty-five healthy postmenopausal women were randomly allocated to receive either conjugated equine estrogens 0.625 mg plus medroxyprogesterone acetate 5 mg (CEE/MPA, Premelle 5, Wyeth-Ayerst Lab, Philadelphia, PA, no.=32) or no therapy (no.=33). Treatment was continuous, and the study period lasted 12 months. Central aortic pressure, augmentation and augmentation index (AI) were determined non-invasively using applanation tonometry. All measurements were performed at baseline and at the end of the study by the same person. Ns differences were found between baseline values and values at the end of the study in either the control or the CEE/MPA group in central systolic aortic pressure (107.0 +/- 13.1 vs 107.6 +/- 11.3 mmHg, p=0.80, and 110.8 +/- 10.8 vs 112.3 +/- 11.4 mmHg, p=0.23, respectively), augmentation (12.6 +/- 4.2 vs 11.9 +/- 4.8 mmHg, p=0.45 and 11.7 +/- 3.7 vs 12.6 +/- 4.2 mmHg, p=0.34, respectively), and percentage of AI (36.8 +/- 9.3 vs 36.3 +/- 10.3, p=0.81 and 34.1 +/- 8.9 vs 34.9 +/- 9.8, p=0.72, respectively). The results of this preliminary report suggest that HT for 1 yr does not have any significant effect on central aortic pressure and wave reflection in healthy postmenopausal women.

Increased stiffness of the abdominal aorta in women with rheumatoid arthritis

OBJECTIVE

To study the distensibility and the diameter of the abdominal aorta and the common carotid artery (CCA) in patients with rheumatoid arthritis (RA), and investigate the relation between mechanical properties of these arteries and disease severity.

METHODS

One hundred and one patients with RA (33 consecutive cases with extra-articular manifestations, and 68 subjects with non-extra-articular disease, matched for age, sex and disease duration) were investigated. Echo-tracking ultrasonography was used to measure stiffness and mean diameter of the abdominal aorta and the CCA. The patients were compared with healthy individuals from the corresponding age group (n=74 for measurements of the aorta, n=64 for the CCA). Predicted values for stiffness and mean diameter, based on age and sex, were calculated.

RESULTS

Stiffness of the abdominal aorta was increased in women with RA [mean percentage of predicted value (% predicted) 180; 95% confidence interval (95% CI) 150-211] but not in men (% predicted 99; 95% CI 75-122). CCA stiffness was less markedly increased, and mean diameters of the aorta and the CCA were not different from the expected. In the RA cohort, patients with extra-articular manifestations tended to have greater stiffness of the aorta (P=0.11), and disability, as indicated by a higher Health Assessment Questionnaire score, was associated with increased aortic stiffness (P=0.04).

CONCLUSION

RA is associated with decreased distensibility of the abdominal aorta in females, and such changes seem to correlate with disease severity. We suggest that arterial stiffness is an important factor in cardiovascular co-morbidity in RA.

Assessment of aortic stiffness and ventricular diastolic functions in patients with Behçet’s disease

BACKGROUND

Behçet's disease is a systemic vasculitis in which studies have given conflicting results about ventricular diastolic functions. However, tissue Doppler echocardiography has never been used in any of these studies. Aortic stiffness, a cardiovascular risk factor, may also precede ventricular dysfunction.

OBJECTIVES

The aim of this study was to assess aortic stiffness and biventricular diastolic functions in patients with Behçet's disease.

METHODS

A total of 26 patients with Behçet's disease (mean age; 33+/-10 years) and 20 age- and sex-matched controls (mean age; 33+/-7 years) were included. Aortic stiffness was evaluated by aortic strain and distensibility. Ventricular diastolic functions were evaluated with both conventional and tissue Doppler echocardiography. Mitral E and A wave, E/A ratio of E wave, deceleration time, and isovolumic relaxation time were calculated.

RESULTS

There was no significant difference in diastolic Doppler parameters between patients and controls. Similarly, there was no significant difference in mitral annular E and A velocities between these two groups. Aortic strain in patients with Behçet's disease was found to be significantly less than in the controls (8.3+/-4.9% and 15.7+/-2.7% respectively, p<0.001). Aortic distensibility was also significantly low in patients with Behçet's disease when compared to controls (0.45+/-0.28 and 0.78+/-0.13 respectively, p<0.001). Beta index values were significantly high in Behçet's patients (7.23+/-5.93 and 2.69+/-0.55 respectively, p<0.001).

CONCLUSION

No significant diastolic dysfunction was found in left and right ventricles in patients with Behçet's disease by using both conventional and tissue Doppler echocardiography. However, an increase in aortic stiffness was found, suggesting an inflammatory involvement of proximal aorta.

Effect of Arterial Lumen Enlargement on Carotid Arterial Compliance in Normotensive Postmenopausal Women

A reduction in central arterial compliance has been identified as an independent risk factor for future cardiovascular disease. The aim of the present study was to determine the influence of age-related carotid arterial enlargement on carotid arterial compliance in postmenopausal females, using a cross-sectional study design. Carotid arterial properties were measured with applanation tonometry and ultrasound system in 113 normotensive females (aged 50-78). Brachial-ankle pulse wave velocity (baPWV) measured by a plethysmographic technique was used as an index of arterial stiffness. In comparisons among the three age groups (50-59, 60-69, and 70-78 years old), baPWV (F=11.9, p<0.001) and carotid systolic (F=4.5, p<0.05) and pulse pressures (F=9.6, p<0.0001), and lumen diameter (F=5.6, p<0.01) increased with advancing age. Carotid arterial compliance gradually decreased with age, but not significantly. A stepwise regression analysis revealed that carotid systolic pressure and lumen diameter and age were independent correlates of carotid arterial compliance. After carotid lumen diameter was taken into account (ANCOVA), the differences in carotid arterial compliance among the three age groups became significant (F=3.8, p<0.05). These results suggest that an increase in arterial lumen diameter might compensate for the age-related increase in arterial stiffness and limit the deterioration of the buffering capacity of the central artery in normotensive postmenopausal females.