Arterial stiffness and cardiovascular risk factors in a population-based study

Long-term pioglitazone therapy improves arterial stiffness in patients with type 2 diabetes mellitus

Pioglitazone, a peroxisome proliferator-activated receptor gamma agonist, not only improves insulin resistance and glycemic control, but may also have additional beneficial vascular effects in patients with type 2 diabetes mellitus. We investigated whether pioglitazone had an influence on arterial stiffness, which is an independent predictor of cardiovascular events, in 204 patients with type 2 diabetes mellitus. A prospective, nonrandomized, open-label trial was performed that involved 41 patients treated with pioglitazone, 46 patients receiving sulfonylureas, 67 patients on insulin, and 50 patients on diet/exercise only. The follow-up period was 56 +/- 3 months. Arterial stiffness was evaluated by using the arterial stiffness index (ASI), which was based on analysis of the pulse wave amplitude pattern obtained during automated blood pressure measurement in the upper limb. The 4 groups had a similar baseline ASI, which was greater than the reference range in each group. Although antidiabetic therapies improved hemoglobin A(1c) and low-density lipoprotein cholesterol, ASI only decreased significantly in the pioglitazone group. Thus, pioglitazone improved abnormal arterial stiffness in patients with type 2 diabetes mellitus via a mechanism beyond the metabolic improvement. These findings may have important clinical implications in the use of pioglitazone in patients with type 2 diabetes mellitus.

Suggestion for a new image-based aortic wall stiffness evaluation technique: arterial wall stiffness index

This study evaluated arterial wall stiffness independent of variant background blood pressure. A new technique-arterial wall stiffness index (AWSI)-was developed and its use verified. Intraluminal pressure and luminal volume were measured on eight swine descending aortas. AWSI was formulated to evaluate absolute arterial wall stiffness independent of variable blood pressure and aortic size. AWSI variability with pressure change was compared with other wall stiffness evaluation parameters. AWSI determined from 100 descending aortic cine CT images and 108 carotid artery ultrasonography datasets were compared with age and Framingham risk score, respectively. Between 50 and 360 mmHg blood pressures, AWSI variance was 5.43% compared to 64.99% for classical compliance. AWSI correlated better with Framingham risk score and age than conservative wall stiffness evaluation methods. AWSI is a suitable method to evaluate arterial wall properties independent of variable background blood pressure and aortic size effects.

Elevated white blood cell count is associated with arterial stiffness

BACKGROUND AND AIMS

White blood cell (WBC) count, a usual marker of systemic inflammation, is known to be associated with atherosclerotic cardiovascular disease. The aim of the present study was to determine the association of WBC count with arterial stiffness measured by brachial-ankle pulse wave velocity (baPWV).

METHODS AND RESULTS

We examined the association between WBC count and baPWV in 788 Korean adults (375 men, 413 women) in a health examination program. The odds ratios for a high baPWV were calculated using multivariate logistic regression analysis after adjusting for confounding variables across WBC count quartiles (Q1: <or=5190, Q2: 5200-6080, Q3: 6090-7310, and Q4: >or=7320 cells/mm(3)). A high baPWV was defined as more than 1440 cm/s (>75th percentile). Age-adjusted baPWV mean values gradually increased with WBC quartiles (Q1=1294, Q2=1322, Q3=1347, and Q4=1367 cm/s). The odds ratios (95% CI) for a high baPWV in each WBC count quartile were 1.00, 1.34 (0.61-3.00), 2.20 (0.96-5.06), and 2.69 (1.15-6.47) after adjusting for age, sex, cigarette smoking, alcohol intake, regular exercise, body mass index (BMI), mean arterial blood pressure, fasting plasma glucose, triglyceride, HDL-cholesterol, gamma-glutamyltransferase (GGT), and uric acid.

CONCLUSION

These findings indicate that elevated WBC count is associated with arterial stiffness. Accordingly, early detection of an elevated WBC count is important for arterial function and the assessment of cardiovascular risk.

The influence of obesity and metabolic risk variables on brachial-ankle pulse wave velocity in healthy adolescents

Measurement of brachial-ankle pulse wave velocity (baPWV) is recognized as a simple and practical method for assessing arterial stiffness. We determined whether the baPWV of adolescents is affected by obesity and its associated metabolic risk variables. A cross-sectional sample of 754 apparently healthy adolescents (383 men and 371 women), aged 15-17 years, was recruited for this study. baPWV was measured by a simple automatic oscillometric technique. Adiposity measures, blood pressure, serum lipoproteins, fasting glucose and insulin were evaluated. The baPWV of the adolescents was significantly higher in men than in women and increased with age in both genders. After being statistically adjusted for age and gender, baPWV was significantly correlated with body mass index, percent body fat, waist-to-height ratio, systolic and diastolic blood pressures, mean arterial pressure, triglycerides, high-density lipoprotein cholesterol (HDL-C), atherogenic index, glucose, insulin, and homoeostasis model assessment of insulin resistance (HOMA-IR). In the multivariate regression analysis, mean arterial pressure, atherogenic index, HOMA-IR, systolic blood pressure and age were found to be significant determinants of baPWV (P<0.001). An increasing number of clustered risk variables, including high values (>gender-specific top quartiles) of waist-to-height ratio, mean arterial pressure, atherogenic index and HOMA-IR showed a graded association with baPWV (P<0.001 for trend). These results suggest that obesity and its associated metabolic abnormalities are important factors in the increased baPWV of adolescents and that baPWV may be useful in investigating early arterial wall changes in this population.

Reference values of aortic pulse wave velocity in the elderly

BACKGROUND

Increased aortic pulse wave velocity (AoPWV) is an independent predictor of cardiovascular morbidity and mortality. There are, however, no generally accepted limits for defining the normal or reference values. The aim of the present study was to define reference values for AoPWV.

PATIENTS AND METHODS

AoPWV was assessed using applanation tonometry (PulsePen device) in a community living ambulatory population of 455 individuals aged 60-75 years. AoPWV was studied in a group of 206 individuals without hypertension or diabetes, called the 'reference-values group' (RVG), and in a group of 249 individuals with hypertension or diabetes, called the hypertension-diabetes group (HDG). The 95th percentile of the samples was used to determine the upper limit of AoPWV reference values.

RESULTS

Mean AoPWV was 8.7+/-2.3 m/s in the RVG and 10.2+/-2.5 m/s in the hypertension-diabetes group (P<0.0001). In the RVG, median AoPWV in the three age subgroups was 8.0 m/s (7.6-8.5) in the 60-64-, 8.0 m/s (7.5-9.0) in the 65-69- and 9.0 m/s (7.9-9.5) in the 70-75-year-old group (NS among groups). In the entire RVG, the upper bounds of the 75th and the 95th percentile of the sample's AoPWV were 10 and 13 m/s, respectively, with no difference between sexes.

CONCLUSION

In elderly individuals of 60-75 years, an AoPWV value below 10 m/s, measured with the PulsePen device, can be considered as a normal value. Values of 10-13 m/s can be considered as 'high normal' or 'borderline', whereas an AoPWV above 13 m/s is frankly elevated. This study provides, for the first time in the elderly, reference values of AoPWV.

Impaired endothelial nitric oxide bioavailability: a common link between aging, hypertension, and atherogenesis?

Endothelial-derived nitric oxide (NO) is responsible for maintaining continuous vasodilator tone and for regulating local perfusion and systemic blood pressure. It also has significant antiproliferative effects on vascular smooth muscle and platelet anti-aggregatory effects. Impaired endothelial-dependent (NO mediated) vasorelaxation is observed in most animal and human models of healthy aging. It also occurs in age-associated conditions such as atherosclerosis and hypertension. Such "endotheliopathy" increases vascular risk in older adults. Studies have indicated that pharmacotherapeutic intervention with angiotensin-converting enzyme inhibitors and 3-hydroxy-3-methyl-glutaryl coenzyme-A reductase inhibitors may improve NO-mediated vasomotor function. This review, evaluates the association between impaired endothelial NO bioavailability, accelerated vascular aging, and the age-associated conditions hypertension and atherogenesis. This is important, because pharmacotherapy aimed at improving endothelial NO bioavailability could modify age-related vascular disease and transform age into a potentially modifiable vascular risk factor, at least in a subpopulation of older adults.

Arterial-ventricular coupling: mechanistic insights into cardiovascular performance at rest and during exercise

Understanding the performance of the left ventricle (LV) requires not only examining the properties of the LV itself, but also investigating the modulating effects of the arterial system on left ventricular performance. The interaction of the LV with the arterial system, termed arterial-ventricular coupling (E(A)/E(LV)), is a central determinant of cardiovascular performance and cardiac energetics. E(A)/E(LV) can be indexed by the ratio of effective arterial elastance (E(A); a measure of the net arterial load exerted on the left ventricle) to left ventricular end-systolic elastance (E(LV); a load-independent measure of left ventricular chamber performance). At rest, in healthy individuals, E(A)/E(LV) is maintained within a narrow range, which allows the cardiovascular system to optimize energetic efficiency at the expense of mechanical efficacy. During exercise, an acute mismatch between the arterial and ventricular systems occurs, due to a disproportionate increase in E(LV) (from an average of 4.3 to 13.2, and 4.7 to 15.5 mmHg.ml(-1).m(-2) in men and women, respectively) vs. E(A) (from an average of 2.3 to 3.2, and 2.3 to 2.9 mmHg.ml(-1).m(-2) in men and women, respectively), to ensure that sufficient cardiac performance is achieved to meet the increased energetic requirements of the body. As a result E(A)/E(LV) decreases from an average of 0.58 to 0.34, and 0.52 to 0.27 in men and women, respectively. In this review, we provide an overview of the concept of E(A)/E(LV), and examine the effects of age, hypertension, and heart failure on E(A)/E(LV) and its components (E(A) and E(LV)) in men and women. We discuss these effects both at rest and during exercise and highlight the mechanistic insights that can be derived from studying E(A)/E(LV).

Arterial stiffness indices in healthy volunteers using non-invasive digital photoplethysmography

BACKGROUND

Increased arterial stiffness is a marker of cardiovascular damage, even in the absence of clinically apparent disease. It is likely to become an important clinical tool in cardiovascular risk assessment.

AIMS AND METHODS

We studied a group of healthy subjects and measured their arterial stiffness by digital photoplethysmography. We aimed to obtain a range of arterial stiffness values, and investigated the influence of age, gender, race, body mass index, fasting lipids and haemodynamic factors.

RESULTS

One hundred and fifty-two healthy subjects, aged between 18 and 67 years, on no medications and with no significant medical illnesses were recruited. The population was predominantly Caucasian (n = 112). Two measures of arterial stiffness were obtained: stiffness index (SI), a measure of large arterial stiffness, and reflection index (RI), a measure of small to medium-sized arterial stiffness. SI and RI were significantly correlated with age, total cholesterol, low-density lipoprotein-cholesterol, heart rate (HR), systolic blood pressure (SBP) and diastolic blood pressure (DBP). Race was a significant independent predictor of SI.

CONCLUSION

Digital photoplethysmography is a portable, operator-independent, reproducible and simple method of measuring arterial stiffness. Ranges of normality of arterial stiffness will depend on the individual's age, race, lipid levels, HR and blood pressure.

Relation of aortic wall thickness and distensibility to cardiovascular risk factors (from the Multi-Ethnic Study of Atherosclerosis [MESA])

To determine the relation between aortic wall thickness (WT) and aortic distensibility (AD) with traditional cardiovascular risk factors in the Multi-Ethnic Study of Atherosclerosis (MESA) cohort, 1,053 participants in MESA who underwent cardiac magnetic resonance imaging were consecutively selected for the measurement of aortic WT and AD. Double inversion-recovery fast spin-echo images of the thoracic aorta were obtained to measure average and maximum WT. AD was measured at the same level using a gradient-echo cine sequence. Average and maximum WT were positively correlated with increasing age, and AD was inversely related to age (p <0.01). Compared with normotensive participants, those with hypertension had significantly greater mean average WT (2.45 vs 2.23 mm, p <0.01) and maximum WT (3.61 vs 3.41 mm, p <0.01) and lower AD (0.15 vs 0.2 mm Hg(-1), p <0.01). In multiple regression analysis, older age and hypertension were significantly associated with higher mean average WT, while older age, male gender, and higher blood pressure were associated with higher mean maximum WT. AD was inversely related to older age, hypertension, current smoking, African American ethnicity, and lower high-density lipoprotein cholesterol level. In conclusion, in the MESA cohort, older age and higher blood pressure were associated with higher aortic WT and lower AD. Decreased AD was further associated with current smoking, African American ethnicity, and higher high-density lipoprotein cholesterol level.

Asymmetric dimethylarginine (ADMA) has a role in regulating systemic vascular tone in young healthy subjects: the cardiovascular risk in young Finns study

BACKGROUND

This study was designed to evaluate whether plasma asymmetric dimethylarginine (ADMA) has any role in predicting hemodynamic responses in clinically healthy young subjects. ADMA, as an endogenous nitric oxide (NO) synthase inhibitor, has been demonstrated to associate with hypertension and vascular reactivity in experimental but not undoubtedly in physiological settings.

METHODS

A total of 199 subjects aged 31.4 years (range 24-39 years) were studied. Plasma ADMA and symmetric dimethylarginine (SDMA) were assessed by isocratic high-pressure liquid chromatography using precolumn derivatization with o-phtaldialdehyde at baseline. Blood pressure (BP) was measured by casual measurements in the beginning of the study and after a follow-up period of 2.45 +/- 0.42 years (range, 1.86-3.19 years). Hemodynamic regulation was assessed by noninvasive methods after a follow-up.

RESULTS

Plasma ADMA had a negative association with resting systemic vascular resistance index (SVRI) (r = -0.23, P < 0.01) and pulse wave velocity (PWV) (r = -0.17, P < 0.05) and positive association with cardiac index (CI) (r = 0.21, P < 0.01) after the follow-up. Plasma ADMA had also negative association with responses of SVRI (r = -0.19, P < 0.01) and positive association with CI (r = 0.25, P < 0.001) in a hemodynamic reactivity test. In a multivariate linear model (R2 = 0.20, P < 0.00001), diastolic BP (R = 0.37, P < 0.00001) and ADMA (R = -0.20, P < 0.01) were significant predictors of SVRI.

CONCLUSIONS

These results suggest that plasma ADMA seems to play a role in the regulation of vascular tone in young healthy subjects.

Impact of age on the independent association of adiposity with pulse-wave velocity in a population sample of African ancestry

BACKGROUND

We aimed to clarify whether age influences the independent relationship between adiposity and pulse-wave velocity (PWV).

METHODS

We explored the effect of age on the independent relationships between indexes of central adiposity (waist circumference (WC) and waist-to-hip ratio (WHR)) and carotid-femoral PWV, central augmentation index (AIc), or pressure wave amplification assessed from applanation tonometry measurements obtained at the radial, carotid, and femoral arteries in 508 randomly selected subjects >16 years of age in a population sample of African ancestry with a high prevalence of excess adiposity ( approximately 63% overweight or obese).

RESULTS

In women a strong interaction between age and either WC or WHR was associated with logPWV independent of confounders and the individual terms (r = 0.68, P < 0.0001). This translated into a markedly greater increase in logPWV with increases in either WC or WHR in women older than the median age as compared to women younger (slopes of WC-logPWV relationships = 0.0031 +/- 0.0009 vs. -0.0007 +/- 0.0007, P < 0.002). In women older than the median age for the group, a one s.d. increase in WC (12.8 cm) translated into a 0.70 m/s increase in PWV as compared to a 0.14 m/s decrease in PWV for each one s.d. increase in WC (13.0 cm) in women younger than the median age (P < 0.001). No index of adiposity was independently associated with the log of AIc or aortic-brachial wave amplification.

CONCLUSION

In women of African ancestry, a greater independent effect of adiposity on PWV is noted in older as compared to younger women.

Beneficial effect of angiotensin II type 1 receptor blocker antihypertensive treatment on arterial stiffness: the role of smoking

The purpose of the present study was to assess angiotensin receptor blocker (ARB) treatment on arterial stiffness in select hypertensive patients and define possible differences between smokers and nonsmokers. The authors evaluated 81 consecutive, nondiabetic patients (mean age, 52 years; 47 men) with uncomplicated essential hypertension with high plasma renin activity who were administered monotherapy with irbesartan, an ARB, at maximal dose. Patients were divided into smokers (n=24) and nonsmokers (n=57). Carotid-radial pulse wave velocity (PWVc-r), carotid-femoral pulse wave velocity (PWVc-f), and augmentation index (AIx) were measured before and 6 months after ARB antihypertensive treatment. All mean values of elastic effect indices were decreased after irbesartan monotherapy (AIx, from 26.3%to 21.2% [P<.01;] PWVc-f, from 7.7 m/s to 7.3 m/s [P<.05], and PWVc-r, from 8.9 m/s to 8.3 m/s [P<.001]). When comparing smokers vs nonsmokers, no difference was noted in AIx and PWVc-f change (P=not significant), while PWVc-r change was greater in smokers compared with nonsmokers (P<.05). Chronic ARB treatment may favorably affect arterial stiffness and wave reflections in hypertensive chronic smokers with elevated plasma renin levels.

Racial (black-white) divergence in the association between adiponectin and arterial stiffness in asymptomatic young adults: the Bogalusa heart study

BACKGROUND

Adiponectin, an adipocytokine with beneficial biological functions relevant to cardiovascular (CV) diseases, and arterial stiffness, an indicator of vascular function, are considered to be important correlates of CV disease risk. Although racial (black-white) divergences in adiponectin and arterial stiffness are known, information is scant regarding the association between these two parameters among asymptomatic young adults within each race.

METHODS

As part of the Bogalusa Heart Study, arterial stiffness was examined noninvasively in terms of aorta-femoral pulse wave velocity (af-PWV) in 991 black and white nondiabetic subjects (72% white, 43% male) aged 24-44 years.

RESULTS

In a multivariate regression model by race that included adiponectin, age, sex, waist circumference, mean arterial pressure, heart rate, homeostasis model assessment of insulin resistance, low- and high-density lipoprotein cholesterols, triglycerides, and cigarette smoking, the significant predictors of af-PWV, in the order of entry, were: mean arterial pressure, age, smoking, and heart rate in both races, followed by adiponectin (inverse relation) in blacks. Further, after adjusting for mean arterial pressure, age, smoking, and heart rate, the odds ratio of finding excess af-PWV (top decile vs. the rest) in individuals with low adiponectin levels (bottom quartile vs. the rest) was significantly higher in blacks (OR: 2.5; 95% CI: 1.1-5.5), but not in whites (OR: 0.9; 95% CI: 0.5-1.9).

CONCLUSIONS

These findings suggest that the status of hypoadiponectinemia is an independent correlate of excess arterial stiffness in asymptomatic young black adults.

The effect of heart rate on wave reflections may be determined by the level of aortic stiffness: clinical and technical implications

BACKGROUND

Augmentation Index (AIx) is related to cardiovascular diseases, risk, and mortality. AIx is associated with heart rate but the effect of aortic stiffness on this relationship has not been studied. The purpose of our study was to investigate the relationship between AIx and heart rate at different aortic stiffness levels.

METHODS

The study consisted of 425 normotensive and untreated hypertensive subjects. Wave reflections and pulse-wave velocity (PWV) were determined by the Sphygmocor and the Complior systems, respectively.

RESULTS

AIx was independently associated with heart rate, age, gender, height, mean blood pressure (BP) and the effective reflection site distance (ERD). The population was divided into three groups of those with different PWV levels (tertiles). The regression lines for AIx with heart rate differed significantly between the 3rd and the other two tertiles of PWV (P = 0.039 for slopes and P = 0.002 for intercepts). This difference remained significant even after adjustment for age, gender, height, mean BP, and distance of wave reflections.

CONCLUSIONS

A significantly stronger correlation of AIx with heart rate was observed in subjects with higher levels of aortic stiffness as compared to those with lower levels; namely, the same increase in the heart rate between subjects, induced a greater decrease in the AIx at higher compared to lower PWV levels. The correction of AIx for heart rate should be reconsidered based on the aortic stiffness level. This finding has implications for interventional studies that aim to improve central hemodynamics but simultaneously affect heart rate. Further studies that show acute modifications of heart rate at different arterial stiffness levels are required to support these findings.

Evidence for functional expression of vascular angiotensin II type 2 receptors in patients with insulin resistance

AIM

Angiotensin II type 2 (AT2) receptors are believed to become over-expressed in response to cardiovascular damage and to mediate beneficial effects (e.g. vasodilation). It is unknown whether AT2 receptors are functionally expressed in patients with insulin resistance (INSR). In this study, we investigated the role of the highly selective AT2 receptor antagonist, PD123319, on arterial stiffness and haemodynamic parameters in patients with INSR, compared with an age- and gender-matched control (N) group to determine whether there is functional expression of vascular AT2 receptors in patients with INSR.

METHODS

We studied 10 subjects with INSR [mean age 28 +/- 5 years, body mass index (BMI) 30.4 +/- 5.4 kg/m(2), mean cholesterol level 4.7 +/- 0.7 mmol/l, mean homeostasis model assessment 2.78 +/- 0.84] and 10 age- and gender-matched normal subjects (mean age 27 +/- 7 years, BMI 23.6 +/- 2.5 kg/m(2), mean cholesterol level 3.9 +/- 0.6 mmol/l). All were normotensive, non-smokers and on no medications. Subjects received a 3-min infusion of PD123319 (10 microg/min). At the end of the infusion, arterial stiffness indices [stiffness index (SI) and reflective index (RI)] and haemodynamic parameters [cardiac index, systemic vascular resistance index (SVRI) and stroke index (ZI)] were measured.

RESULTS

RI (mean % change: INSR 13.8 +/- 15.5%, N -0.2 +/- 4.6, p = 0.04) and SVRI (mean % change: INSR 13.5 +/- 9.7%, N -1.5 +/- 5.7, p = 0.005) increased significantly in response to PD123319 infusion in patients with INSR compared with controls. There were no significant changes in SI, systolic blood pressure, diastolic blood pressure and ZI.

CONCLUSION

The results suggest the functional expression of AT2 receptors in small vessels that determine the inflection of the digital volume pulse wave in patients with INSR, possibly as an indicator of early vascular damage.

Arterial stiffness and haemodynamic response to vasoactive medication in subjects with insulin-resistance syndrome

INSR (insulin-resistance syndrome) affects 25% of the Australian population and is associated with increased cardiovascular risk. In the present study, we postulated that early cardiovascular changes in these individuals may be associated with an activated RAS (renin–angiotensin system). We studied 26 subjects: 13 with INSR [waist circumference, 99±6 cm; HOMA (homoeostasis model assessment) score, 2.5±0.3] and 13 NCs (normals controls; waist circumference, 77±2 cm; HOMA score, 1.4±0.2). All received intravenous GTN (glyceryl trinitrate; 10, 20 and 40 μg/min), L-NMMA (NG-monomethyl-L-arginine; 3 mg/kg of body weight), AngII (angiotensin II; 8 and 16 ng/min), the selective AT2R (AngII type 2 receptor) inhibitor PD123319 (10 and 20 μg/min) and AngII (16 ng/min)+PD123319 (20 μg/min). At the end of each infusion, arterial stiffness indices [SI (stiffness index) and RI (reflection index)] and haemodynamic parameters were measured. There was a significantly higher RI response to AngII (P=0.0004 for both 8 and 16 ng/min doses) and to PD123319 (P=0.004 and P=0.03 for 10 and 20 μg/min doses respectively) in subjects with INSR compared with NCs. Co-infusion of AngII and PD123319 did not lead to additive changes in RI. RI responses to L-NMMA and GTN were not significantly different in both groups. No significant differences in SI and haemodynamic responses were detected. In conclusion, AT1R (AngII type 1 receptor) and AT2R activity produce arterial stiffness changes in subjects with INSR. Evidence of increased AT1R- and AT2R-mediated responses in small-to-medium-sized arteries in INSR was found, and may play an early role in the pathogenesis of vascular changes in INSR before haemodynamic changes become apparent.

Metabolic syndrome and its components in relation to brachial-ankle pulse wave velocity in middle-aged Taiwanese males

To evaluate the association of The study is to evaluate the association of metabolic syndrome (MS) and its components on brachial-ankle pulse wave velocity (baPWV), an indirect marker of subclinical atherosclerosis, in middle-aged Taiwanese males. A total of 442 men aged 40 to 65 years were included in this cross-sectional survey. Arterial stiffness was measured using a non-invasive method by baPWV. MS is defined by the presence of ≥ 3 components using the modified National Cholesterol Education Program criteria. The mean baPWV was 1478.6 and 1520.3 cm/sec in normal-weight and overweight adults, respectively. Age, systolic blood pressure (BP), diastolic BP, and fasting blood glucose (FBG) correlated with baPWV levels in normal-weight and overweight males. In multiple logistic regression analysis, after adjusting for potential confounders, MS and its components (such as high BP and high FBG) were significantly associated with abnormal baPWV (≥1400 cm/sec) (p < 0.001). MS and its components are significantly associated with abnormal baPWV in Taiwanese middle-aged males and in addition, high BP was the component of MS most significantly associated with abnormal baPWV.

[Effect of olmesartan medoxomil on arterial stiffness in patients with essential hypertension]

BACKGROUND AND OBJECTIVE

Arterial stiffness is one of the early lesions of the arteries in patients with cardiovascular risk factors. Pulse wave velocity (PWV) is one form of measurement of arterial stiffness. The renin-angiotensin system seems to be involved in the inflammatory mechanisms that take place at level of the vascular wall. The aim of this study is to investigate the effect of olmesartan (angiotensin II type 1 receptor antagonist) in the arterial stiffness, measuring the PWV. Another secondary objective is to determine the antihypertensive efficacy with ambulatory blood pressure monitoring (ABPM).

PATIENTS AND METHOD

Seventy-one patients with mild-to-moderate essential hypertension were consecutively included. Clinical blood pressure (CBP), ABPM and PWV, automatized measurement between the carotid and femoral arteries using the Complior device (Colson, Paris, France), were determined in a baseline and after 16 weeks of treatment with 10-40 mg of olmesartan.

RESULTS

Sixty-four patients completed the study. The mean (standard deviation) age was 48.31 (9.69) years and 44.9% were men. A significant reduction of the PWV was observed. The basal PWV was 10.50 (1.87) m/s and after treatment was 9.26 (1.84) m/s (p < 0.0001). We found only a positive correlation between the decline of PWV and diastolic blood pressure (BP). We could not find such correlation with systolic BP. The reduction degree was higher in the youngest patients where BP decrease was less evident. The BP decreased in a significant way (p < 0.0001) doing so in CBP and in the periods of 24 h, diurnal and nocturnal.

CONCLUSIONS

Olmesartan has shown effective to decrease the arterial stiffness, mainly in young patients. This effect seems to be independent of the decrease of the systolic BP. Olmesartan reduces effectively the BP during the 24 h.

Beneficial effect of beraprost sodium plus telmisartan in the prevention of arterial stiffness development in elderly patients with hypertension and cerebral infarction

Beraprost sodium (BPS, an analogue of prostacyclin) and telmisartan (TS, an angiotensin receptor blocker) have been reported to have a preventive effect on arterial stiffness in patients with cardiovascular diseases. The purpose of this study was to estimate the effects of a combined therapy using BPS and TS on arterial pulse wave velocity (PWV) values in elderly patients with hypertension and cerebral infarction. Over a 3-month period, 80 subjects with hypertension and histories of cerebral infarction received BPS only (120 microg/day p.o.), TS only (40 mg/day p.o.), both BPS and TS, or no medication at all (control). Arterial PWV and ankle brachial indices (ABI) were determined prior to and after 3 months of drug administration. During the follow-up, there were no significant changes in any of the parameters monitored with the exception of a significant decrease in systolic blood pressure in the BPS only, TS only, and BPS plus TS groups when compared to controls. The difference values for PWV in the control group, BPS only group, TS only group, and BPS plus TS group were +232.5, -114.6, -151.5, and -248.1 cm/s, respectively. The reduction values were significantly more pronounced in the BPS plus TS group than in the BPS only (P=0.037) and the TS only (P=0.022) groups. When BPS is combined with TS, an overall additive effect is seen in the improvement of PWV in Japanese patients with hypertension and cerebral infarction. This combination therapy is more beneficial than the corresponding monotherapies.

Pulse wave velocity reference values in healthy adults aged 26?75�years

The stiffening of arteries is associated with various cardiovascular diseases. Arterial stiffening can be studied utilizing arterial pulse wave velocity (PWV), but the absence of reliable reference values for PWV has limited its use in clinical practice. The aim of this study was to establish a range of reference values for PWV. PWV was examined by measuring the time difference of systolic pulse waves in arteries from the aortic arch to the popliteal artery using whole-body impedance cardiography (ICG). The study population consisted of 799 individuals (age range 25-76 years), 283 of whom had no evidence of cardiovascular disease, and a low burden of risk factors was selected to represent an apparently healthy population. In healthy study population, PWV was higher in males (8 x 9 +/- 1 x 8 m s(-1)) than females (8 x 1 +/- 2 x 0 m s(-1), P<0 x 001). Young males had lower PWV values than old males. Correspondingly, young females also had lower PWV values than old females. PWV was clearly associated with age, and PWV was higher in young and middle-aged males than in females. There was no statistically significant difference between old males and females in PWV. In conclusion, whole-body ICG provides a practical method for PWV measurement. Reference values can be useful in the clinical management of patients, especially in detecting early vascular disease or an increased risk of cardiovascular complications.

Carotid intima–media thickness, carotid distensibility and mitral, aortic valve calcification: a useful diagnostic parameter of systemic atherosclerotic disease

BACKGROUND

Mitral (MAC) and aortic (AVC) calcification are observed more frequently in the elderly and are associated with coronary artery disease, aortic atheroma and peripheral arterial atherosclerotic disease. Common carotid intima-media thickness (cIMT) and distensibility (cDIST) are also independent predictors of adverse cardiovascular outcomes. We examined the relationship between the degree of MAC-AVC and cIMT and cDIST.

METHODS AND RESULTS

One hundred and forty-three patients referred for transthoracic echocardiography and carotid artery echo-Doppler were evaluated; the variables measured were: systemic blood pressure, pulse pressure; body mass index, traditional risk factors, cIMT, cDIST (cDIST = [(csD - cdD)/PP]/csD; where csD and cdD were systolic and diastolic carotid diameters, respectively). MAC and AVC score, based on acoustic densitometry, were: 1 = absence of annular/valvular (av) sclerosis/calcification; 2 = av sclerosis; 3 = av calcification; 4 = av calcification; 5 = av calcification with no recognition of the leaflets; the resulting score was the highest for either valvular annulus. Mean cIMT increased linearly with increasing valvular calcification score (P < 0.0001) whereas cDIST decreased for scores 1 to 5 (P < 0.0001). Distribution of cIMT quartiles showed that 75% of the patients in the lowest quartile had a score of 1 and 70% of patients in the highest quartile had a score of 5; 47% of the patients in the highest quartile of cDIST had a score of 1, whereas 60% of patients in the lowest quartile of cDIST had a score of 4.

CONCLUSIONS

The MAC and AVC score identifies subgroups of patients with different cIMT and cDIST. These data may confirm MAC-AVC as a useful important diagnostic parameter of systemic atherosclerotic disease.

Viscerally obese women with normal body weight have greater brachial-ankle pulse wave velocity than nonviscerally obese women with excessive body weight

OBJECTIVE

To confirm the association of visceral obesity and brachial-ankle pulse wave velocity (baPWV) and to compare metabolic indices and baPWV between individuals who have normal body weight but are viscerally obese and individuals with excessive body weight who are not viscerally obese.

PATIENTS AND MEASUREMENTS

We recruited a total of 150 women, aged 22 to 67 years. We assessed body composition, measured by computed tomography (CT), and divided the study population into four groups, based on visceral adipose tissue area (normal, normal body weight but viscerally obese, excessive body weight but not viscerally obese, and excessive body weight and viscerally obese). The baPWV was measured, using a volume plethysmographic instrument.

RESULTS

Despite lower levels of total body fat, the women who had a normal body weight but were viscerally obese had a higher plasma triglyceride level and baPWV measurement and greater subcutaneous fat area (SFA) and thigh SFA than the women with excessive body weight who were not viscerally obese. After adjustment for age, mean blood pressure (BP), body mass index (BMI), triglyceride levels, fasting insulin levels, and free fatty acid (FFA) levels, baPWV was independently correlated with abdominal visceral fat area, as measured by CT (P = 0.001).

CONCLUSIONS

Mean baPWV was higher in women with normal body weight who were viscerally obese than in women who had excessive body weight but were not viscerally obese, and abdominal visceral fat was an independent factor for baPWV. These results suggest that early detection and intervention in viscerally obese individuals, even those within a normal BMI range, could be needed to prevent atherosclerosis and cardiovascular disease (CVD).

Soluble tumor necrosis factor receptor 2 is independently associated with pulse wave velocity in nonobese Japanese patients with type 2 diabetes mellitus

The aim of the present study was to investigate the factors contributing to pulse wave velocity (PWV) in patients with type 2 diabetes mellitus. We focused on tumor necrosis factor (TNF) including soluble TNF receptors (sTNF-R1, sTNF-R2) in this study because TNF seems to be associated with the progression of atherosclerosis and because the relationships between PWV and TNF were not yet examined in type 2 diabetic patients. Univariate regression analyses showed that PWV was positively correlated with age (r=0.492, P<.001), diabetes duration (r=0.251, P=.021), systolic (r=.595, P<.001) and diastolic (r=0.248, P=.022) blood pressure, antihypertensive medication (r=0.268, P=.013), and the concentrations of sTNF-R1 (r=0.354, P=.001) and sTNF-R2 (r=0.415, P<.001). Although there was a positive correlation between TNF-alpha and sTNF-R1 (r=0.382, P<.001) or sTNF-R2 (r=0.394, P<.001), TNF-alpha was not associated with PWV. Other variables including gender were not associated with PWV. Multiple regression analyses showed that PWV was independently predicted by the level of age (F=15.1), systolic blood pressure (F=31.6), and sTNF-R2 (F=5.2), which explained 49.2% of the variability of PWV. From these results, it can be concluded that serum soluble TNF receptor is an important independent factor associated with aortic PWV in type 2 diabetic patients.

Haemodynamic determinants of elevated pulse wave velocity during acute isometric handgrip exercise

BACKGROUND

Measurement of pulse wave velocity (PWV) provides a reliable index of vascular stiffness. Despite its widespread application, the physiological interrelationships between PWV, blood pressure (BP) and in particular, heart rate (HR), have yet to be fully elucidated. Furthermore, little is known about altered arterial compliance during acute exercise.

AIM

To examine the effects of 3-min supine non-dominant isometric handgrip exercise (ISOMEX), performed at 30% of maximum voluntary contraction, on carotid-radial PWV, BP and HR in the dominant arm of 51 healthy subjects.

RESULTS

During exercise, PWV correlated strongly with diastolic BP (r = 0.55, p < 0.01) and mean arterial pressure (r = 0.51, p < 0.01). PWV and HR failed to correlate at rest or during exercise.

CONCLUSION

ISOMEX invoked an elevated PWV, which is predominantly related to BP or factors determining it, and not HR. The carotid-radial PWV stress test is a simple measurement that may have prognostic potential for use in large-scale population studies.

Metabolic syndrome and arterial stiffness: the Health 2000 Survey

Metabolic syndrome and its components have been associated with arterial stiffness and cardiovascular disease. The objective of this study was to examine the independent influences of metabolic syndrome, its components, and other cardiovascular risk factors on arterial stiffness as well as to compare 2 definitions for metabolic syndrome (National Cholesterol Education Program [NCEP] and International Diabetes Federation [IDF]) in their ability to identify subjects with arterial stiffness. The study population consisted of 401 Finnish men and women aged 45 years and older who participated in a substudy of the Finnish population-based Health 2000 Survey. Pulse wave velocity (PWV) measured by whole-body impedance cardiography was used as a marker of elevated arterial stiffness. In multivariate models, systolic blood pressure, age, waist circumference, and fasting blood glucose (P < or = .001 for all) were independent determinants for PWV. In the models including metabolic syndrome instead of its components, the NCEP and IDF definitions were similarly associated with PWV (P < or = .01 for both), the other independent determinants being age, sex (P < .001 for both) and plasma C-reactive protein concentration (P = .016 and P = .005 in models containing the NCEP and IDF definitions, respectively). Systolic blood pressure, age, waist circumference, and fasting blood glucose level were independently associated with increased arterial stiffness. Metabolic syndrome determined increased arterial stiffness independently of other known cardiovascular risk factors. The NCEP and IDF definitions did not differ in their ability to identify subjects with increased arterial stiffness.

Relationship between blood pressure parameters and pulse wave velocity in normotensive and hypertensive subjects: invasive study

Blood pressure (BP) is one of the most important contributing factors to pulse wave velocity (PWV), a classic measure of arterial stiffness. Although there have been many non-invasive studies to show the relation between arterial stiffness and BP, the results are controversial. The aim of this study is to evaluate the role of BP as an influencing factor on PWV using invasive method. We observed 174 normotensive and untreated hypertensive subjects using coronary angiography. Arterial stiffness was assessed through aorto-femoral PWV by foot-to-foot velocity method using fluid-filled system. And BP was measured by pressure wave at the right common femoral artery. From univariate analysis, age, diabetes mellitus (DM), hypertension, waist, waist-to-hip ratio, total cholesterol-to-high-density lipoprotein cholesterol ratio, systolic BP (SBP), pulse pressure (PP) and mean arterial pressure (MAP) showed significant association with PWV. To avoid multiple colinearity among SBP, PP and MAP, we performed multiple regression analysis predicting PWV thrice. Age, DM and each BP were significantly and consistently correlated to PWV. In the first and third modules, compared to age, SBP and MAP were less strong predictors, respectively. However, PP was the stronger predictor than age and DM in the second module. Lastly, we simultaneously forced MAP and PP with other variables in the fourth multivariate analysis. Age, DM and PP remained significantly correlated with PWV, but the significance of MAP was lost. This is the first invasive study to suggest that PP has the strongest correlation with PWV among a variety of BP parameters.

Two new criteria of the metabolic syndrome: prevalence and the association with brachial-ankle pulse wave velocity in Japanese male workers

In 1998 and 2001, The World Health Organization and the National Cholesterol Education Program Adult Treatment Panel III proposed working criteria for the metabolic syndrome (MS), but they are not perfect for use in diverse ethnicities. In 2005, the International Diabetes Federation (IDF) and eight societies in Japan respectively proposed new criteria. However, there has been no report regarding the application of these new criteria in Japanese workplaces. We conducted a cross-sectional study of 377 healthy Japanese men aged 20-64 yr who worked in a chemical factory in Kanagawa, Japan. Participants completed a self-reported questionnaire, underwent a physical examination including waist measurements and brachial-ankle pulse wave velocity (baPWV), and provided overnight fasting blood samples. The prevalence of MS in Japanese men was 17.0% and 13.5% according to the new IDF and Japanese criteria respectively. In both of the new criteria, baPWV was significantly higher in those with MS than those without MS (1,563 +/- 264.2 vs 1,362 +/- 204.6 cm/sec, p<0.001 in the new IDF criterion; 1,574 +/- 265.2 vs 1,368 +/- 209.1 cm/sec, p<0.001 in the Japanese criterion). In the analysis of the 5 or 6 subgroups stratified according to the number of MS components, baPWV increased significantly with increasing number of MS components (p for trend<0.01 in both criteria). The new IDF and Japanese criterion are both good for diagnosing MS among Japanese because a linear increase in baPWV occurred with increasing MS components after adjustment for potential confounding factors. Further studies are expected using these new criteria.

Increase in aortic pulse wave velocity is associated with abnormal postprandial triglyceride response

BACKGROUND

Aortic pulse wave velocity (aPWV), an index of aortic distensibility, and postprandial hypertriglyceridemia are recognized as independent cardiovascular risk factors.

HYPOTHESIS

The aim of this study was to evaluate the relationship between postprandial hypertriglyceridemia and changes in aPWV.

METHODS

We prospectively studied 45 patients (mean age 48 [14] years, 28.9% men), who were submitted to a standardized fat meal (FM) test. According to their triglyceride (TG) levels 2, 4, 6, and 8 h after the FM, the patients were divided into two groups: Group 1 (31 patients) with postprandial TG levels < or = 219 mg/dl, and Group 2 (14 patients) with TG levels > 219 mg/dl at one of the aforementioned time intervals. Before and 6 h after the FM, aPWV was measured noninvasively.

RESULTS

Baseline characteristics in the two groups were similar, except for higher TG, pulse pressure, waist-to-hip ratio, percentage of patients who smoked or had arterial hypertension, and lower high-density lipoprotein cholesterol levels in Group 2. Postprandially, aPWV was higher in Group 2 [11.2(2.7) vs. 9.1(2.1) m/s, p = 0.004]. Changes in aPWV correlated with TG changes from baseline to 6 h after FM (r = 0.539, p < 0.001) and with the areas under the TG curve (r = 0.617, p < 0.001). A postprandial TG increase of 100 mg/dl resulted in a 0.88 m/s rise of aPWV.

CONCLUSION

An increase in aPWV 6 h after an FM test correlates positively with abnormal postprandial hypertriglyceridemia. These relationships, reported here for the first time, could be of practical use for better evaluation of patient prognosis.

Prediction of cognitive function by arterial stiffness in the very elderly

BACKGROUND

Cognitive function is impaired in elderly subjects, so the aim of the present study was to determine the role of arterial stiffness on cognitive function.

METHODS AND RESULTS

Cognitive function and arterial stiffness were assessed by the Mini-Mental State Examination (MMSE) and measurement of the brachial-ankle pulse wave velocity (PWV), respectively. The cross-sectional association of the MMSE score and PWV was studied in 203 subjects (87 men, 116 women), all of whom were 85 years old. Sex distribution, systolic and diastolic blood pressures did not differ between the normal (MMSE score >or=24, n=128) and impaired MMSE groups (MMSE score <24, n=75). In contrast, the PWV was significantly increased in the impaired MMSE group than in the normal MMSE group (25.0+/-0.8 vs 22.9+/-0.5 m/s, p<0.05). In multiple regression analysis, the PWV was also independently and significantly associated with the MMSE score.

CONCLUSIONS

These results suggest that cognitive function could be predicted by arterial stiffness, as assessed by the PWV, in the very old. Preventing atherosclerosis may play an important role in preserving normal cognitive function until very old age.

Non-invasively measured structural and functional arterial characteristics and coronary heart disease risk in middle aged and elderly men

BACKGROUND

In cardiovascular (CV) epidemiology, interest increases in studying etiologic and prognostic implications of early structural or functional changes of the large arteries. Examples of such measurements are pulse wave velocity (PWV), carotid intima-media thickness (CIMT) and augmentation index (AIx). PWV and CIMT are established markers of CV risk whereas the role of AIx as indicator of risk has not fully been established. Therefore, our aim was to relate AIx to CV risk and to compare the magnitude of relations of PWV, CIMT and AIx to CV risk.

METHODS

Two hundred and ninty-nine men free from cardiovascular disease (mean age 59.2 years), participated in this cross-sectional study. Cardiovascular risk profile was determined and 10-year coronary heart disease risk was estimated using the Framingham risk score (FRS). PWV, CIMT and AIx were measured and data were analyzed using linear regression models.

RESULTS

PWV and CIMT were strongest related to FRS whereas AIx showed the weakest relation. Ten-year coronary heart disease risk increased 6.24%, 95% confidence interval (CI) [5.11;7.37] per standard deviation (S.D.) increase in PWV, 6.39% [5.24;7.54] per S.D. increase in CIMT and 2.50% [1.19;3.80] per S.D. increase in AIx.

CONCLUSION

In middle aged and elderly men AIx is related to CV risk. However, compared with AIx, PWV and CIMT seem better markers of cardiovascular risk.

Estimation of an age-specific reference interval for pulse wave velocity: a meta-analysis

OBJECTIVE

To estimate an age-specific reference interval for carotid-femoral pulse wave velocity (PWV), an index of aortic stiffness, and to determine the predictive values of the reference range for detecting those at moderate and high risk of cardiovascular disease (CVD).

DESIGN AND METHODS

We searched MEDLINE using PubMed from 1995 to 2005 for all studies in which Carotid-Femoral PWV was measured using a Complior (Colson, Paris, France) apparatus in Caucasian non-pregnant adults. Twenty-five studies were included, covering 30 groups of subjects; these groups were classified a priori into low (normal), moderate, and high CVD risk categories, with 2008, 5979, and 180 (total 8167) subjects, respectively. Individual-level data were simulated for each group, and an age-specific reference interval was calculated by using fractional polynomial functions.

RESULTS

We plotted an age-adjusted normal curve for PWV with 2.5, 5, 50, 90, 95, and 97.5 centile limits. Applying this reference interval to the moderate- and high-risk groups using simulations yielded sensitivities of 34.3 [95% confidence interval (CI) 33.2-35.3] and 57.2 (95% CI 55.2-59.3), respectively, specificities of 95.3 (95% CI 94.8-95.8) and 95.3 (95% CI 94.4-96.2), respectively, and positive likelihood ratios of 7.3 and 12.2, respectively.

CONCLUSION

We constructed an age-adjusted reference curve for PWV. Using the 95th centile of this curve as a threshold (e.g. 10.94, 11.86, and 13.18 m/s for 20, 40, and 60 years old) shows construct validity, as it appears to identify medium and high CVD risk groups reasonably accurately. This reference range needs to be tested using other datasets.

Ambulatory blood pressure variability and brachial-ankle pulse wave velocity in untreated hypertensive patients

Blood pressure (BP) variability is estimated as the standard deviation of 24-h ambulatory BP. The present study was performed to determine the effect of the mean 24-h ambulatory BP values and standard deviations on arterial wall stiffness assessed by brachial-ankle pulse wave velocity (baPWV). Brachial-ankle pulse wave velocity, carotid intima-media thickness (IMT), urinary albumin excretion (UAE) and 24-h ambulatory BP were measured before the start of antihypertensive therapy in 203 newly diagnosed hypertensive patients (53.3+/-0.7 years old; clinic systolic/diastolic BP: 154+/-1/98+/-1 mm Hg), and univariate and multivariate regression analyses of these clinical and biological parameters were performed. Univariate regression analyses revealed a significant association between mean baPWV values and the standard deviations of ambulatory systolic/diastolic BP. Mean ambulatory systolic/diastolic BP values were also associated with UAE, and the standard deviations of ambulatory systolic BP were associated with maximum carotid IMT. Quintile analyses showed that patients with a mean 24-h ambulatory mean BP value and standard deviation below 110 and 20 mm Hg, respectively, had the lowest baPWV. Moreover, the multivariate regression analyses confirmed a significant correlation between baPWV and the standard deviation of 24-h ambulatory systolic BP. In conclusion, untreated hypertensive patients with a higher 24-h ambulatory systolic BP variability had stiffer arterial walls. Ambulatory systolic BP variability may be involved in stiffening of the arteries of hypertensive patients.

Selective angiotensin receptor antagonism with valsartan decreases arterial stiffness independently of blood pressure lowering in hypertensive patients

Angiotensin II plays a key role in the development of vascular disease. We examined the long-term effects of selective angiotensin II receptor (ATR) blockade with valsartan on arterial wall stiffness. Brachial to ankle pulse wave velocity (baPWV) was measured in 28 women and 25 men with hypertension (mean age: 62+/-2 years). The measurements were repeated after 24 weeks of treatment with valsartan, 40 to 160 mg/day, with (n=10) or without (n=36) concomitant statin therapy. By multiple regression analysis, baseline baPWV was correlated with age (p<0.001), systolic blood pressure (SBP, p<0.0001), body mass index (p=0.018), and pulse pressure (p=0.005), but not with total cholesterol (p=0.446). Valsartan lowered mean SBP and diastolic blood pressure (DBP) from 155+/-3 to 140+/-3 mmHg and from 90+/-2 to 82+/-2 mmHg, respectively, and mean baPWV from 1,853+/-49 to 1,682+/-52 cm/s. Lowering of baPWV was not influenced by statin therapy. An overlap analysis was performed to separate the effect of angiotensin II receptor blockade from that of blood pressure (BP) lowering. The decrease in the baPWV value of 1,794+/-46 cm/s before valsartan (n=39) vs. 1,663+/-45 cm/s during valsartan (p=0.048, n=31) at a similar mean SBP level (149+/-2 vs. 146+/-3 mmHg, p=0.304) confirmed that ATR blockade had a beneficial effect independent of BP lowering. SBP strongly influences baPWV. However, the decrease in baPWV with valsartan was independent of BP lowering. Statins had no synergistic effect on baPWV. Lowering of baPWV may account for the therapeutic benefit conferred by valsartan independent of its BP-lowering effect.

Prediction of aortic augmentation index using radial pulse transmission-wave analysis

OBJECTIVE

Current arterial transfer functions have low capability in predicting aortic augmentation index (AIx) from radial pulse contour (RPC), because of the difficulty in accurately identifying the merging point (inflection point) in the derived aortic pulse contour (APC). We hypothesize that the formation time between each characteristic wave in APC is about one-third of ejection duration (ED/3). We sought to assess the accuracy of ED/3 in identifying the merging point in APC as compared to the conventional differential method. In addition, we sought to derive the AIx from RPC based on an arterial transfer function and the ED/3 method.

METHODS

APC and RPC sequences were measured digitally and simultaneously in 60 subjects (37 males; aged 60 +/- 10 years). An ensemble-averaged RPC-to-APC transfer function was determined from 30 randomly selected subjects and was used to derive APC sequences in the 30 additional subjects. The accuracy of AIx predicted from RPC was determined.

RESULTS

In patients with a clearly identifiable merging point in APC, the ED/3 method identified the merging point of measured APC within 1.97 +/- 0.60 ms of that identified by the conventional differential method, with identical AIx. The AIx and merging point of derived APC using the ED/3 method were also within 0.22 +/- 1.01% and 1.81 +/- 1.64 ms, respectively, of those of the measured APC using the conventional differential method. The accuracy of the predicted AIx was independent of age, sex, body-mass index and presence of hypertension.

CONCLUSION

In a quiet resting state, the ED/3 is an alternative method for identifying the merging point in APC. In conjunction with transfer-function technique, AIx can be derived accurately from RPC.

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.

Effects of intravenous PD 123319 on haemodynamic and arterial stiffness indices in healthy volunteers

Relatively little is known about the functional expression of cardiovascular angiotensin type 2 (AT2)-receptors in healthy young adult humans. We performed a randomised, placebo-controlled crossover study of the effects of intravenous administration of the selective AT2-receptor antagonist PD 123319 on haemodynamics and arterial stiffness in normal volunteers. Sixteen normal subjects aged 29.9+/-13.8 years (range 18-30 years) received an intravenous infusion of PD 123319 (10 mcg/minute for 5 minutes) and placebo, separated by one week. Haemodynamics (cardiac index, stroke index and systemic vascular resistance) were measured non-invasively using a BioZ.com thoracic impedance detection system. Blood pressure was measured from an arm cuff using oscillometry. Stiffness index, a measure of arterial stiffness, was measured using a Pulse Trace recorder. No significant changes in blood pressure (p=0.92), cardiac index (p=0.52), stroke index (p=0.61), systemic vascular resistance index (p=0.32) or stiffness index (p=0.57) was demonstrated following PD 123319 infusion, compared with placebo. The results of this study do not support the functional presence of cardiovascular AT2-receptors that mediate acute haemodynamic effects in healthy young adults. It remains possible that higher doses of PD 123319 may be required to demonstrate functional cardiovascular AT2-receptors in this population, if they are present.