Comparative study of methodologies for pulse wave velocity estimation

Arterial stiffness, estimated by pulse wave velocity (PWV), is an independent predictor of cardiovascular mortality and morbidity. However, the clinical applicability of these measurements and the elaboration of reference PWV values are difficult due to differences between the various devices used. In a population of 50 subjects aged 20-84 years, we compared PWV measurements with three frequently used devices: the Complior and the PulsePen, both of which determine aortic PWV as the delay between carotid and femoral pressure wave and the PulseTrace, which estimates the Stiffness Index (SI) by analyzing photoplethysmographic waves acquired on the fingertip. PWV was measured twice by each device. Coefficient of variation of PWV was 12.3, 12.4 and 14.5% for PulsePen, Complior and PulseTrace, respectively. These measurements were compared with the reference method, that is, a simultaneous acquisition of pressure waves using two tonometers. High correlation coefficients with the reference method were observed for PulsePen (r = 0.99) and Complior (r = 0.83), whereas for PulseTrace correlation with the reference method was much lower (r = 0.55). Upon Bland-Altman analysis, mean differences of values +/- 2s.d. versus the reference method were -0.15 +/- 0.62 m/s, 2.09 +/- 2.68 m/s and -1.12 +/- 4.92 m/s, for PulsePen, Complior and Pulse-Trace, respectively. This study confirms the reliability of Complior and PulsePen devices in estimating PWV, while the SI determined by the PulseTrace device was found to be inappropriate as a surrogate of PWV. The present results indicate the urgent need for evaluation and comparison of the different devices to standardize PWV measurements and establish reference values.     

Noninvasive evaluation of arterial abnormalities in young patients with neurofibromatosis type 1

Neurofibromatosis regroups at least two different autosomal dominant genetic disorders: neurofibromatosis type 1 (NF1) and neurofibromatosis type 2 (NF2). Vascular disease is an underestimated complication of NF1. Few studies are available on this, all based on case reports. Neurofibromin, NF1 protein product, has also been detected in aortic smooth muscle. The purpose of this study was to evaluate the physical properties of the vessels, by measuring the carotid-femoral pulse wave velocity (PWV). This parameter was assessed by the Complior, a new noninvasive, validated device, used to screen a large population. The authors studied 64 neurofibromatosis patients (34 boys and 30 girls) with a mean age of 12 years (range 5-25 years). To investigate the presence of vascular lesions, aortic stiffness was evaluated by carotid-femoral PWV by using an automatic processor (Complior). They compared data from the PWV with a control group (30 healthy children, 17 boys and 13 girls, mean age 11 years, range 5-23 years). The calculated mean PWV in the control group was 6.5 +/- 1.15 m/s. The mean PWV of the 64 young patients with NF1 was 6.3 +/- 1.02 m/s. There was no difference between the two groups (p=0.39). Nevertheless, analysis of the linear regression has shown a linear relationship between systolic blood pressure (SBP) and PWV in the control group, while in NF1 patients this relationship is not present. The authors suggest that the coexistence of different factors, such as intimal proliferation, thinning media, fragmentation of the elastic tissue, irregularity, stenosis and tortuosity of the vessels, dysplasia of the small vessels, that counterbalance PWV, normalize the mean value. They emphasize the importance of a careful vascular evaluation, using noninvasive method, such as Complior. This device is well accepted by NF1 patients.     

Arterial distensibility in Wegener's granulomatosis: a carotid-femoral pulse wave velocity study.

OBJECTIVE: The purpose of this study was to test the hypothesis; that chronic inflammation may impair vascular function and lead to an increase of arterial pulse wave velocity (PWV) in patients with Wegener's granulomatosis (WG). METHODS: We recruited 5 patients with WG and 5 healthy age and sex matched controls in this cross-sectional case-controlled study. Aortic PWV was determined by using an automatic device (Complior Colson, France), which allowed on-line pulse wave recording and automatic calculation of PWV. RESULTS: The carotid-femoral (aortic) PWV was increased in patients with WG as compared with control group (p=0.04). Although we found positive correlation between PWV and heart rate (r=0.75, p=0.01), we did not find any significant correlation between PWV and anthropometric and other hemodynamic parameters (p>0.05). In addition, we found positive correlation between PWV and erythrocyte sedimentation rate in patients with WG (r=0.90, p=0.03). CONCLUSION: Pulse wave velocity is increased and arterial distensibility decreased in patients with WG. Measurements of carotid-femoral (aortic) PWV may provide an easy and noninvasive technique to identify patients at increased risk of arterial disease.     

Pulse wave velocity as endpoint in large-scale intervention trial. The Complior study. Scientific, Quality Control, Coordination and Investigation Committees of the Complior Study

OBJECTIVE: To evaluate the ability of an antihypertensive therapy to improve arterial stiffness as assessed by aortic pulse wave velocity (PWV) in a large population of hypertensive patients. SETTING: Sixty-nine healthcare centres, private and institutional (19 countries). PATIENTS: Subjects aged 18-79 years, with essential hypertension. A total of 2,187 patients were enrolled; 1,703 (52% male) completed the study: mean age = 50 +/- 12 years; mean baseline systolic/diastolic blood pressure (S/D BP) = 158 +/- 15/98 +/- 7 mmHg; mean baseline carotid-femoral PWV = 11.6 +/- 2.4 m/s. INTERVENTIONS: Patients were treated for 6 months, starting with perindopril (angiotensin converting enzyme (ACE) inhibitor) 4 mg once daily (OD), increased to 8 mg OD, and combined to diuretic (indapamide 2.5 mg OD) if BP was uncontrolled (> 140/90 mmHg). RESULTS: It was feasible to measure carotid-femoral PWV using the automatic device Complior at inclusion, 2 and 6 months, along with conventional BP assessments in a population of 1,703 patients. Significant decreases (P < 0.001) in BP (systolic: -23.7 +/- 16.8, diastolic: -14.6 +/- 10 mmHg), and carotid-femoral PWV (-1.1 +/- 1.4 m/s) were obtained at 2 and 6 months. CONCLUSIONS: The Complior Study is the first study to show the feasibility of a large-scale intervention trial using PWV as the endpoint in hypertensive patients. Adequate results may be obtained using an automatic device and rigorous criteria for assessment. A long-term controlled intervention study is needed to confirm the results of the present uncontrolled trial.     

Increased pulse wave velocity and shortened pulse wave propagation time in young patients with rheumatoid arthritis

BACKGROUND: Rheumatoid arthritis (RA) is a systemic immune and inflammatory disease associated with excess cardiovascular morbidity and mortality. Pulse wave velocity (PWV) is an index of arterial stiffness and a marker of cardiovascular events. OBJECTIVE: To investigate arterial stiffness using carotid-femoral (aortic) PWV measurements in young patients with RA. PATIENTS AND METHODS: Eight patients (aged 21 to 34 years, seven women, mean RA duration 13.8+/-12.6 months) with RA according to the criteria of the American College of Rheumatology, and eight age- and sex-matched control subjects (aged 22 to 34 years, seven women) were recruited. Aortic PWV was determined using an automatic device, the Complior (Complior Colson, France), which allowed on-line pulse wave recording and automatic calculation of PWV. RESULTS: The carotid-femoral PWV, systolic blood pressure and heart rate were higher in young patients with RA than in sex- and age-matched control subjects (P=0.03, P=0.02 and P=0.002, respectively). In the young patients with RA, pulse wave propagation time between measurement sites was significantly shorter than in the control group (P=0.02). There were no significant differences in the sex, age, body mass index, waist to hip ratio, diastolic blood pressure, mean blood pressure or pulse pressure between the two groups (P=1.00, P=0.71, P=0.20, P=0.66, P=0.55, P=0.07 and P=0.11, respectively). CONCLUSION: The carotid-femoral PWV is increased and pulse wave propagation time is decreased in young patients with RA. Measurements of carotid-femoral PWV may provide a simple and noninvasive technique for identifying patients at increased risk of vascular disease.     

Clinical usefulness and limitations of brachial-ankle pulse wave velocity in the evaluation of cardiovascular complications in hypertensive patients.

The goal of this study was to clarify the clinical usefulness and limitations of brachial-ankle pulse wave velocity (PWV) to evaluate hypertensive complications, in comparison with carotid-femoral PWV. Patients with essential hypertension (n=296, male/female=161/135; age=61.1+/-0.7 years) were enrolled. We measured brachial-ankle PWV, femoral-ankle PWV and carotid-femoral PWV simultaneously, and evaluated target organ damage and associated clinical conditions (cerebrovascular and cardiovascular disease) using the World Health Organization classification modified in 1999. Carotid-femoral PWV (p<0.0001; r=0.521) and brachial-ankle PWV (p<0.0001; r=0.478) but not femoral-ankle PWV were significantly correlated with age. Carotid-femoral PWV was significantly higher in patients with associated clinical conditions compared with that in patients with target organ damage (p<0.05) and those with no complications (p<0.0001). Brachial-ankle PWV was significantly higher in patients with associated clinical conditions (p<0.05) and target organ damage (p<0.05) compared to those with no complications, but there was no significant difference in brachial-ankle PWV between these two groups. Moreover, femoral-ankle PWV was significantly lower in patients with associated clinical conditions compared with that in patients with target organ damage (p<0.05). These data suggest that brachial-ankle PWV could underestimate arterial stiffness in hypertensive patients with a history of cardiovascular events.     

Comparison of aortic pulse wave velocity measured by three techniques: Complior, SphygmoCor and Arteriograph

BACKGROUND: New 2007 European Society of Hypertension guidelines recommend measuring arterial stiffness in patients with arterial hypertension, suggesting a carotid-femoral pulse wave velocity over 12 m/s as an estimate of subclinical organ damage. Considering this cutoff point, it is worth exploring whether or not there are significant differences in results obtained using various techniques for measuring aortic pulse wave velocity. The aim of the study was to compare aortic pulse wave velocity measurements using Complior, SphygmoCor, and Arteriograph devices, and to assess the effect of pulse wave transit time and traveled distance on pulse wave velocity values. METHODS: Aortic pulse wave velocity was measured on a single visit, using these devices, in randomized order, in a group of 64 patients with grade 1 or 2 arterial hypertension. RESULTS: Aortic pulse wave velocity measured using Complior (10.1 +/- 1.7 m/s) was significantly higher than that obtained using SphygmoCor (8.1 +/- 1.1 m/s) or Arteriograph (8.6 +/- 1.3 m/s). No differences were noted between pulse wave velocity measurements using SphygmoCor and Arteriograph. Between-method comparison revealed that differences in traveled distance were significant: Complior versus Arteriograph [0.09 m, Confidence interval (CI): 0.08-0.12 m, P < 0.05], Complior versus SphygmoCor (0.15 m, CI: 0.13-0.16 m, P < 0.05), Arteriograph versus SphygmoCor (0.05 m, CI: 0.03-0.07 m, P < 0.05). No between-method differences were found for transit times. CONCLUSION: Differences in pulse wave velocity obtained by compared devices resulted primarily from using various methods for measuring traveled distance. It appears reasonable to establish uniform principles for the measurement of traveled distance. Because a large number of prognosis/survival studies used direct distance between carotid and femoral sites of pulse wave recording, this distance should be mostly recommended.     

北京某体检人群代谢综合征对踝臂脉搏波速度的影响研究

目的分析北京某健康体检人群代谢综合征(metabolic syndrome,MS)对踝臂脉搏波速度(bra-chial-ankle pulse wave velocity,baPWV)的影响。方法2008年5月行对北京某健康体检人群常规体检以及口服葡萄糖耐量试验(OGTT)和相关代谢指标检查,动脉硬化测定仪VP-2000测定双侧肢体的baPWV。按中华医学会糖尿病学分会(2004)MS评估标准确定有无MS组分异常并分组,分别比较各组之间双侧baPWV的变化特点,分析代谢异常与baPWV的相关性。结果该人群MS的患病率是13.26%,其中4项代谢指标均异常者占2.43%。随着代谢异常组分增加,baPWV逐渐增加,各组间比较差异有统计学意义(P0.05),均明显高于正常对照组。即使单一代谢成分异常组,其baPWV也显著高于正常对照组(P0.05),并且以单纯高血压组baPWV增高最显著。相关分析可见代谢异常与baPWV存在相关性(左侧R=0.42,P0.01,右侧R=0.45,P0.01)。结论MS中血压、血糖、血脂异常均是baPWV增加的危险因素,随着代谢异常数的增多,baPWV进一步增加。     

Home blood pressure is as reliable as ambulatory blood pressure in predicting target-organ damage in hypertension

BACKGROUND: Our objective was to assess the value of home blood pressure (BP) monitoring in comparison to office BP measurements and ambulatory monitoring in predicting hypertension-induced target-organ damage. METHODS: Sixty-eight untreated patients with hypertension with at least two routine prestudy office visits were included (mean age, 48.6 +/- 9.1 [SD] years; 50 men). Office BP was measured in two study visits, home BP was measured for 6 workdays, and ambulatory BP was monitored for 24 h. All BP measurements were obtained using validated electronic devices. Target-organ damage was assessed by measuring the echocardiographic left-ventricular mass index (LVMI), urinary albumin excretion rate (AER) in two overnight urine collections, and carotid-femoral pulse-wave velocity (PWV) (Complior device; Colson, Garges-les-Gonesse, Paris, France). RESULTS: The correlation coefficients of LVMI with office BP were 0.24/0.15 (systolic/diastolic), with home BP 0.35/0.21 (systolic, P < .01), and with 24-h ambulatory BP 0.23/0.19, awake 0.21/0.16, and asleep 0.28/0.26 (asleep, both P < .05). The correlation coefficients of AER with office BP were 0.24/0.31 (diastolic, P < .05), with home BP 0.28/0.26 (both P < .05), and with 24-h ambulatory BP 0.25/0.24, awake 0.24/0.25 (diastolic, P < .05), and asleep 0.26/0.18 (systolic, P < .05). There was a trend for negative correlations between PWV and diastolic BP measurements (not significant). In multiple-regression models assessing independent predictors of each of the three indices of target-organ damage, systolic home BP and age were the only independent predictors of increased LVMI that reached borderline statistical significance. CONCLUSIONS: These data suggest that home BP is as reliable as ambulatory monitoring in predicting hypertension-induced target-organ damage, and is superior to carefully taken office measurements.     

Takayasu's arteritis: a cause of prolonged arterial stiffness

OBJECTIVES: Cardiovascular disease is a major cause of mortality and morbidity in patients with Takayasu's arteritis (TA). Increased arterial stiffness is an independent risk factor and predictor of cardiovascular mortality in a variety of diseases. Pulse wave velocity (PWV) and the augmentation index (AI) are used as clinical measurements of arterial stiffness. METHODS: Data are presented from 10 patients with TA and 11 normal controls obtained between 2000 and 2004. Arterial compliance was assessed non-invasively by measurement of PWV, using the Complior system, and calculation of the aortic AI. RESULTS: TA patients (mean age 40.8+/-13.2 yr) were compared with a control group of healthy women from a parallel study (mean age 32.3+/-5.5 yr). The mean carotid-femoral PWV (PWV-CF) was higher in TA patients (P = 0.03). In addition, both aortic AI derived from the radial artery (P = 0.002) and carotid AI (P = 0.03) were higher in TA patients compared with controls. PWV-CF did not correlate with CRP (r = - 0.23, P = 0.23) or ESR (r = - 0.19, P = 0.27). Similar results were obtained for the correlation of carotid-radial PWV with CRP (r = 0.15, P = 0.32) and ESR (r = 0.33, P = 0.14). CONCLUSIONS: Our data show that TA is associated with elevated arterial stiffness in the central aorta, which may persist when the disease is quiescent. These data suggest that PWV represents a means by which cardiovascular risk can be detected and monitored in TA, and highlights the importance of effective management of cardiovascular risk factors in these patients.     

Determination of aortic pulse wave velocity from waveform decomposition of the central aortic pressure pulse

Aortic pulse wave velocity (PWV), calculated from pulse transit time (PTT) using 2 separate pulse recordings over a known distance, is a significant biomarker of cardiovascular risk. This study evaluates a novel method of determining PTT from waveform decomposition of central aortic pressure using a single pulse measurement. Aortic pressure was estimated from a transformed radial pulse and decomposed into forward and backward waves using a triangular flow wave. Pulse transit time was determined from cross-correlation of forward and backward waves. Pulse transit time, representing twice the PTT between 2 specific sites, was compared with independent measurements of carotid-femoral PTT in a cohort of 46 subjects (23 females; age 57+/-14 years). Linear regression between measured PTT (y; milliseconds) and calculated PTT (x; milliseconds) was y=1.05x-2.1 (r=0.67; P<0.001). This model was tested in a separate group of 44 subjects (21 females; age 55+/-14 years) by comparing measured carotid-femoral PWV (y; meters per second) and PWV calculated using the estimated value of PTT (eTR/2) and carotid femoral distance (x; meters per second; y=1.21x-2.5; r=0.82; P<0.001). Findings indicate that the time lag between the forward and backward waves obtained from the decomposition of aortic pressure wave can be used to determine PWV along the aortic trunk and shows good agreement with carotid-femoral PWV. This technique can be used as a noninvasive and nonintrusive method for measurement of aortic PWV using a single pressure recording.     

Evaluation of carotid-femoral pulse wave velocity: influence of timing algorithm and heart rate

Carotid-femoral pulse wave velocity (PWV), a measure of arterial stiffness, is determined from the time taken for the arterial pulse to propagate from the carotid to the femoral artery. Propagation time is measured variously from the foot of the waveform or point of maximum upslope. We investigated whether these methods give comparable values of PWV at rest, during beta-adrenergic stimulation, and pacing-induced tachycardia. In subjects at rest (n=43), values obtained using the foot-to-foot method (SphygmoCor system) were 1.7+/-0.75 m/s (mean+/-SD) greater than those obtained using the maximum slope (Complior system) at a mean value of 12 m/s. Isoprotenerol (0.5 to 1.5 microg/min; n=10), and pacing (in subjects with permanent pacemakers; n=11) increased heart rate but had differential effects on systolic blood pressure and pulse pressure. The increase in heart rate produced by isoprotenerol (18+/-3 bpm) and pacing (40 bpm) was associated with an increase in PWV measured using both systems (increases of 0.7+/-0.2 m/s and 0.9+/-0.2 m/s for SphygmoCor and Complior, respectively, during isoprotenerol and increases of 2.1+/-0.5 m/s and 1.1+/-0.2 m/s for SphygmoCor and Complior, respectively, during pacing, each P<0.001). Reanalysis of waveforms recorded from the Complior system using the foot-to-foot method produced similar values of PWV to those obtained with the SphygmoCor, confirming that the difference between these systems was attributable to the timing algorithm rather than other aspects of signal acquisition. Carotid-femoral PWV is critically dependent on the method used to determine propagation time, but this does not account for variation of PWV with heart rate.     

Acute effects of oral melatonin administration on arterial distensibility, as determined by carotid-femoral pulse wave velocity, in healthy young men

The aim of the present study was to investigate the effects of melatonin administration on arterial distensibility by using carotid-femoral (aortic) pulse wave velocity (PWV) measurements in healthy young men. Ten men were studied (five men in the melatonin group and five men in the placebo group) by physicians. Carotid-femoral (aortic) PWV, blood pressure and plasma melatonin were measured in the supine position before and 60 min after oral administration of melatonin or placebo. Although carotid-femoral (aortic) PWV, systolic blood pressure and mean blood pressure were decreased, pulse wave propagation time and plasma melatonin levels were increased at 60 min after oral melatonin (1 mg) administration (P=0.04, P=0.04, P=0.04, P=0.04 and P=0.04, respectively). No significant differences were found between all parameters in the placebo group (P>0.05). In conclusion, these findings indicate that melatonin administration, compared with placebo, decreased carotid-femoral PWV and systolic blood pressure in the supine position in healthy young men. Administration of melatonin may have an inhibitory effect on sympathetic tone.     

Assessment of arterial distensibility in patients with cardiac syndrome X

This study aims to investigate arterial distensibility by using carotid-femoral (aortic) pulse wave velocity measurements in patients with cardiac syndrome X. The authors studied 10 patients with cardiac syndrome X (mean age 49.4 +/-7.5, 39 to 67 years old, 3 men) and 10 healthy subjects (mean age 50.0 +/-10.5, 38 to 70 years old, 3 men). Carotid-femoral pulse wave velocity measured by a Complior Colson device was calculated for each patient. The carotid-femoral pulse wave velocity was increased in patients with cardiac syndrome X as compared with age-matched control subjects (10.25 +/-1.28 vs 8.95 +/-0.89 m/s, p = 0.01). In contrast, there were no significant differences in the age, weight, height, body mass index, waist/hip ratio, systolic blood pressure, diastolic blood pressure, mean blood pressure, pulse pressure, and heart rate (p=0.76,p=0.17,p=0.36,p=0.08, p=0.21,p=0.14,p=0.89,p=0.30,p=0.10, p = 0.36, respectively). No significant correlation was found between pulse wave velocity and age, sex, height, weight, heart rate, systolic blood pressure, diastolic blood pressure, mean blood pressure, and pulse pressure in the studied groups (p>0.05). The arterial distensibility was decreased in patients with cardiac syndrome X. The deterioration in these patients showed that this disease might be a more generalized disturbance of the vasculature. Measurements of carotid-femoral pulse wave velocity may provide a simple and noninvasive technique to identify patients at increased risk of vascular disease.     

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.     

Assessment of vascular aging and atherosclerosis in hypertensive subjects: second derivative of photoplethysmogram versus pulse wave velocity

The pulse wave velocity (PWV) and the photoplethysmogram (PTG) are noninvasive methods for evaluating the pulse wave. The PWV has been associated with age and arterial hypertension, and an index of the second derivative of PTG (SDPTG) is correlated with age and other risk factors for atherosclerosis. The aim of this study was to compare SDPTG and PWV concerning the influencing factors of vascular compliance, including age and atherosclerosis, in a large hypertensive population. We studied consecutively 524 essential hypertensives, 140 with atherosclerotic alterations (AA), defined on the basis of clinical events including coronary heart disease, peripheral vascular disease, stroke, and abdominal aorta aneurysm. The PWV carotid-femoral was measured by a Complior device and the SDPTG was recorded by Fukuda FCP-3166. The augmentation index (AUI) of PTG was defined as the ratio of the late systolic peak to that of the early systolic peak in the pulse. The SDPTG consists of an a,b,c, and d wave in systole and an e wave in diastole; an SDPTG aging index (AI) was calculated as (b-c-d-e)/a. The patients with AA presented a higher PWV (14.9 +/- 4 m/sec v 12.4 +/- 2 m/sec, P < .001), PTG AUI (0.322 +/- 0.16 v 0.252 +/-0.09, P < .001), and SDPTG AI (-0.093 +/- 0.03 v -0.271 +/- 0.018, P < .001). However, in patients 60 years of age, only PWV remained higher in those with AA, whereas in patients >60 yr, both PWV and SDPTG AI remained higher in those with AA. The PWV was independently influenced by age, systolic blood pressure, glucose, AA, and plasma creatinine, whereas the PTG AUI was influenced by age and systolic pressure and the SDPTG AI by age and AA. In a logistic regression model for the presence of AA, including age, plasma creatinine, smoking, and diastolic BP, PWV was a significant independent determinant of AA, whereas SDPTG-AI weakly entered into the model. This study provides evidence that the aortic PWV reflects better than the SDPTG the modifications of the arterial compliance related to age, blood pressure, and atherosclerosis. However, the SDPTG AI may be useful for evaluation of vascular aging in hypertensives.     

Measurement of the brachial-ankle pulse wave velocity and flow-mediated dilatation in young, healthy smokers.

The brachial-ankle pulse wave velocity (PWV) is a quick test which adequately estimates arterial stiffness. Because flow-mediated dilatation (FMD) of the brachial artery assesses an essential endothelial function, we tested the hypothesis that the brachial-ankle PWV could reflect the early stages of endothelial dysfunction caused by smoking in young, healthy subjects. Fifty-seven healthy subjects (13 females and 44 males; mean 29.9+/-5.6 years) were enrolled. Twenty-six of the subjects (30.4+/-5.7 years) were active smokers, with a mean cumulative nicotine consumption of 10.0+/-8.6 pack/years, and thus were assigned to the smoking group. Thirty-one subjects without a history of smoking (29.5+/-5.5 years) were assigned to the non-smoking group. The brachial-ankle PWV and arterial blood pressure were simultaneously measured using a recently established, non-invasive automatic device (model BP-203RPE; Nihon Colin, Tokyo, Japan). Endothelium-dependent FMD was induced by reactive hyperemia, while endothelium-independent vasodilation of the brachial artery was induced by administration of sublingual nitroglycerin spray. The FMD was lower in the smoking group than in the non-smoking group (p<0.05). There was no significant difference between the two groups with respect to the brachial-ankle PWV. In the non-smoking group, multiple stepwise regression analysis revealed that FMD was predicted by the systolic blood pressure (F=16.351). In the smoking group, statistical analysis revealed that FMD was independently predicted by either the brachial-ankle PWV (F=8.108) or the subject's age (F=4.381). Our results suggest that a reduction in FMD is closely associated with the early stages of endothelial dysfunction caused by cigarette smoking in young, healthy subjects, which is at least partly reflected by the PWV value.     

Effects of inhibition of basal nitric oxide synthesis on carotid-femoral pulse wave velocity and augmentation index in humans

Aortic stiffness, as measured by carotid-femoral pulse wave velocity (PWV), is a powerful, independent predictor of vascular risk. PWV in muscular arteries is influenced by basal nitric oxide (NO) release. It is not known whether NO also influences carotid-femoral PWV. We examined the effects of an NO synthase inhibitor, NG-monomethyl-l-arginine (L-NMMA), on carotid-femoral PWV and aortic augmentation index (AIx, an indirect measure of arterial stiffness). To control for effects of L-NMMA on distending pressure, we used doses of norepinephrine and dobutamine that caused similar changes in mean arterial blood pressure (MAP). Healthy men (32 to 48 years old, n=8) were studied on 4 occasions and received, in random order, vehicle, L-NMMA (3 mg x kg(-1) by intravenous bolus followed by 3 mg x kg(-1) x h(-1)), norepinephrine (50 ng x kg(-1) x min(-1)), and dobutamine (2.5 to 10 microg x kg(-1) x min(-1)), each for 30 minutes. PWV and AIx were measured by carotid-femoral PWV and radial tonometry, respectively. L-NMMA and norepinephrine increased MAP by 7.8+/-1.7 and 9.7+/-2.1 mm Hg, respectively (each P<0.05 vs vehicle) and increased PWV by 0.7+/-0.2 and 1.0+/-0.3 m x s(-1) (each P<0.01 vs vehicle). Dobutamine, at doses that produced a similar increase in MAP (9.6+/-2.9 mm Hg), increased PWV by 0.8+/-0.2 m x s(-1) (P<0.01 vs vehicle). Changes in PWV caused by the 3 pressor agents were closely correlated with changes in MAP (R>0.99, P<0.0001). L-NMMA and norepinephrine increased AIx, but dobutamine decreased AIx (P<0.01 vs norepinephrine and L-NMMA). Effects of inhibition of basal NO release on carotid-femoral PWV can be explained by the change in MAP that this causes rather than any specific effect of NO inhibition within the aorta.     

Relationship between albumin excretion rate and aortic stiffness in untreated essential hypertensive patients

OBJECTIVES: To evaluate, in a group of nondiabetic essential hypertensive patients with normal renal function, the relationship between albumin excretion rate (AER) and carotid-femoral pulse wave velocity (PWV), as an index of aortic stiffness. DESIGN: Cross-sectional study. SETTING: Outpatient hypertension clinic. SUBJECTS: Seventy patients with mild-to-moderate essential hypertension, aged 42 +/- 8 years, never pharmacologically treated. All subjects underwent routine laboratory tests, 24-h ambulatory blood pressure (BP) monitoring, measurement of carotid-femoral PWV, by means of a computerized method, and AER. RESULTS: Microalbuminuric patients (AER > or = 20 microg min(-1); n = 19), when compared with normoalbuminuric subjects, showed more elevated 24-h BP (136/88 +/- 10/10 vs. 128/83 +/- 7/6 mmHg; P < 0.001 and P = 0.013, for systolic and diastolic BP respectively) and higher values of carotid-femoral PWV (10.4 +/- 2 m s(-1) vs. 9.2 +/- 1.3; P = 0.006). This latter difference remained statistically significant, even after correction by ancova for 24-h systolic and diastolic BP, and body mass index (BMI, P = 0.016). Univariate regression analysis disclosed a tight correlation between AER and carotid-femoral PWV (r = 0.42; P = 0.0003). This association was confirmed in a multiple regression model (beta = 0.35; P = 0.009) in which, as independent variables, besides PWV, 24-h BP, age, serum glucose values, smoking status, gender and BMI, were added. CONCLUSIONS: Our results seem to confirm that microalbuminuria may represent the early renal manifestation of a widespread vascular dysfunction, and therefore it is an integrated marker of cardiovascular risk.     

Comparison of ankle-brachial pressure index and pulse wave velocity as markers of the presence of coronary artery disease in subjects with a high risk of atherosclerotic cardiovascular disease

Recently, a measurement device that can simultaneously measure the ankle-brachial pressure index (ABI) and brachial-ankle pulse wave velocity (PWV) has become available. The present study compares the applicability of ABI and PWV as markers for predicting the prevalence of coronary artery disease (CAD) in subjects with a high risk of atherosclerotic cardiovascular disease. The ABI and brachial-ankle PWV were measured in 472 consecutive subjects who subsequently underwent coronary angiography for diagnosis or exclusion of CAD. The prevalence of CAD in the lowest ABI quartile was higher than those in the other 3 ABI quartiles, whereas the prevalence in the lowest brachial-ankle PWV quartile was lower than those in the other 3 brachial-ankle PWV quartiles. A multivariate logistic regression analysis demonstrated that the lowest ABI quartile was a significant independent variable for the prevalence of CAD and that the lowest brachial-ankle PWV quartile was a significant independent variable for the absence of CAD in a population. Thus, a low ABI is an independent marker for an additive risk of CAD, whereas a low brachial-ankle PWV may be used as an independent marker for excluding the risk of CAD among subjects with a high risk of atherosclerotic cardiovascular disease.