Numerical Model of the Human Cardiovascular System–Korotkoff Sound Simulation

The numerical simulation of the Korotkoff sounds is realized by a 14 segment hemodynamic model of the cardiovascular system developed in the Institute of Thermomechanics, Czech Academy of Sciences. The cardiovascular system is modeled by four segments of the pulsating heart and by 10 vascular segments of pulmonary and systemic circuits connected with the heart in series. To better understand the generation of Korotkoff sounds the systemic arterial flow is studied in detail by a distributed parameter model. The analysis of self-excited oscillations in a collapsible tube (i.e., the systemic artery) is based on a one-dimensional model where the effect of expected flow separation is replaced by the change of viscous friction along the tube.     

Assessment of Mechanical Homogeneity of the Arterial Wall by an Artery-Inversion Test

The aim of this study was to apply a method to check, by means of a simple mechanical test, the homogeneity in the elastic properties of an artery. The method is based on in vitro measurements of the pressure–radius relationships of the artery in the normal configuration and when the artery is turned inside out. The mechanical properties of the arterial wall are described by a strain energy function (SEF). The wall is assumed to be homogeneous and the SEF is determined using data from the pressure–radius curves obtained in vitro or in vivo. Fresh pig carotids were mounted on an inflation–extension apparatus allowing the measurement of diameter by means of an ultrasonic device, and the internal pressure by means of a catheter. First, the SEF is determined using the pressure–radius relationship. Geometrical characteristics of the zero stress state (ZSS) are measured on a longitudinally cut ring of the artery. This state is used as reference state for the measurements of the deformations. The artery is then turned inside out to create a different initial strain distribution in the wall. The measured pressure–radius curve is then compared to the one predicted using the SEF obtained by the control test. The two curves should be identical for a homogeneous arterial wall and different if the wall is nonhomogeneous. The comparison between the pressure–radius relationship of the inverted artery and the theoretical one for a pig carotid showed that the pig carotid is elastically homogeneous.     

Investigation of the Dynamic Behavior of a Collapsible-Tube Model Through Nonlinear Analysis

In this paper, the dynamic behavior of a collapsible-tube system consisting of a reservoir with inlet and outlet flow conditions is investigated using nonlinear analysis approach. The reservoir is subject to a constant inlet flow rate and the outlet flow rate and the pressure–flow rate relation of the downstream collapsible regime is presented by a constitutive model containing a cubic nonlinearity. Within certain operating regimes, the model exhibits self-excited time-periodic oscillations, which can be identified with pressure-drop oscillations. These oscillations are rationalized to be relaxation oscillations and the qualitative features of the response including the limit cycle and the mechanisms are discussed based on numerical results.     

Carotid pressure is a better predictor of coronary artery disease severity than brachial pressure

The mechanisms relating pulse pressure to cardiovascular outcome may include surrogacy for coronary disease severity. Although pulse pressure is typically measured at the brachial artery, central pulse pressure and its principal determinant, large-artery stiffness, may relate more closely to disease severity. This study aimed to determine the relationships between large-artery stiffness and carotid and brachial blood pressures and coronary artery disease severity. One hundred fourteen male patients with coronary artery disease (age 60+/-8 years, mean+/-SD) and 57 age-matched healthy male controls (age 59+/-9 years) were recruited. Patients were classified into 2 groups based on the magnitude of their maximum coronary stenosis: moderate (50% to 89%) and severe (>/=90%). Large-artery stiffness was assessed as systemic arterial compliance and carotid-femoral pulse wave velocity. Mean pressure was not different between the 3 groups. Systemic compliance and carotid pulse pressure were significantly different between all 3 groups, with compliance lowest and pressure highest in the severe group (P<0.05). Pulse wave velocity was higher in patients with severe stenosis than in those with moderate stenosis (P<0.01) and those in the control group (P<0.001). Brachial pulse pressure was higher in patients than in controls (P<0.05), but there was no difference between the 2 disease groups. In separate multivariate analyses, carotid pressures and systemic arterial compliance were determinants of coronary artery disease severity, independent of age, smoking status, body mass index, mean arterial pressure, heart rate, cholesterol levels (total, LDL, and HDL), triglycerides, and beta-antagonist and lipid-lowering therapy (P<0.001), whereas brachial pressures and pulse wave velocity were not. In conclusion, central blood pressures and systemic arterial compliance are more sensitive markers of coronary artery disease severity than brachial pressures.     

Improved diagnosis and management of hyper- and hypothyroidism by timing the arterial sounds.

"Sphygmo-Recording," a non-invasive method for timing the arterial pulse wave contour provides an objective measure of responses to medication in patients with hyper- and hypothyroidism. The QKd interval, i.e., the interval from the onset of the QRS complex (Q) to the onset of the Korotkoff sounds (K) at the brachial artery when the sphygmomanometer cuff is at diastolic pressure (d) is the QKd interval. QKd is normally 205 +/- 12 msec. In the hyperthyroidism the QKd interval may be shortened to 110 msec. In hypothyroidism the QKd interval may be prolonged to 320 msec. Changes in QKd parallel changes in clinical status and serum total T4 and T3, measured by radioimmunoassay. QKd can be used as an objective guide to antithyroid therapy in hyperthyroidism and replacement therapy with thyroid hormone in hypothyroid individuals.     

Technical and methodologic aspects of ambulatory long-term blood pressure monitoring systems

The development of noninvasive, portable blood pressure measuring units began in 1962 with semi-automatic devices and cassette recorders, followed by the first automatic unit in 1968 and the introduction of digital storage system in 1978. Systems in common use today consist of a portable, battery-driven blood pressure monitor and a print-out unit. In the following, the System 5200 from SpaceLabs, which has been in use for three years in our clinic, will be described. TECHNICAL ASPECTS: In a monitor unit, amplication and filtering of analogue data measured and differentiation between signal and noise is carried out. An A/D converter digitalizes the analogue data. An integrated microprocessor analyses measured data, regulates inflation and deflation of the cuff pressure, out-put of measured and calculated values on an LCD display and storage of data. Data from 200 measurements is stored in a 2K byte RAM CMOS system. A personal computer serves for programming the monitor and evaluation of the stored data. Blood pressure measurement is carried out auscultatory with a microphone or oscillometrically if Korotkoff sounds are not detected. If the signal is disturbed, measurement is repeated within two minutes. Blood pressure measurements are performed at freely-programmable intervals from six to 60 minutes; varying time intervals can also be chosen. AUSCULTATORY BLOOD PRESSURE MEASUREMENT: A miniature pump integrated in the monitor inflates the cuff within a few seconds to a pressure of 160 mmHg or, on subsequent measurements, to 25 mmHg above the last recorded systolic value. On registration of Korotkoff sounds, the cuff pressure is increased in steps of 25 mmHg until the sounds disappear and then deflated in steps of 3 to 5 mmHg. On detection of the first Korotkoff sound, the instantaneous cuff pressure (which is converted to an electric signal by a transducer) is stored as the systolic value. Further deflation then occurs rapidly to 90 mmHg or 10 mmHg above the last measured diastolic value. With higher diastolic values, again, there is an increase in cuff pressure in steps of 25 mmHg until the onset of Korotkoff sounds and then renewed deflation in steps of 3 to 5 mmHg. On disappearance of the Korotkoff sounds, the prevailing cuff pressure is recorded and stored as the diastolic value (Figure 1). To register the Korotkoff sounds optimally, the microphone is positioned above the brachial artery.(ABSTRACT TRUNCATED AT 400 WORDS)     

Hemodynamic effects of labetalol on the humeral artery of the hypertensive patient. A double-blind study versus placebo

Forearm arterial hemodynamics, including measurements of brachial artery diameter and compliance with pulsed Doppler velocimetry were determined before and after acute administration of labetalol in patients with sustained essential hypertension. Labetalol caused a significant and rapid drop in blood pressure with a decrease in forearm vascular resistance and an increase in brachial blood flow. Brachial artery diameter did not change while arterial compliance significantly increased. The study provided evidence that labetalol caused a shift of the pressure-brachial artery diameter curve toward lower values of blood pressure, indicating a pharmacological effect of alpha and beta blockade on the hypertensive arterial wall.     

Effects of nicorandil on arterial and venous vessels of the forearm in systemic hypertension

The effects of a single oral dose of 20 mg of nicorandil were evaluated in 12 untreated patients with mild to moderate essential hypertension. Serial measurements of arterial pressures were obtained by means of an automatic device (Dynamap) up to 120 minutes after drug administration. Forearm hemodynamics were determined with a pulsed Doppler velocimeter, or strain gauge mecanography and plethysmography enabling measurement of the diameter, velocity and flow of the brachial artery as well as the arterial pulse wave velocity and forearm venous tone. In addition, local vascular resistance, compliance and impedance were deduced.

Nicorandil administration produced a significant decrease in systolic and diastolic blood pressure, from 18 minutes after dosing which lasted up to the end of the study (i.e., 120 minutes after drug administration) (p < 0.01). This decrease in blood pressure was not associated with reflex tachycardia. The brachial artery diameter increased significantly (p < 0.01) with no change in brachial artery blood flow. A decrease in brachial-radial pulse wave velocity and arterial impedance (p < 0.01) and an increase in arterial compliance were observed.

Thus, this study demonstrated an antihypertensive activity of a single oral administration of nicorandil without baroreflex activation.

This decrease in blood pressure was associated with a dilation of peripheral large arteries leading to an increase in arterial compliance. Thus, clinical testing to evaluate the antianginal activity of nicorandil, especially in hypertensive patients with coronary heart disease, should be encouraged.     

Effect of celiprolol on large and small arteries of the forearm circulation in hypertensive patients

Summary Celiprolol, a new highly cardioselective beta blocker, also has direct vasodilating properties. Since the noninvasive echo Doppler technique applied to the forearm circulation (brachial artery) allows the differentiation of arteriolar vasodilation (revealed by the increasing arterial blood flow velocity) from vasodilation of large arteries (shown by an increase in arterial diameter), it seems important to study the site of celiprolol's vasodilating effect. Thirty-five hypertensive patients, (21 male, 14 female; mean age, 59±11, range 42–79 years) were treated with increasing doses of celiprolol, 200 and 400 mg, over 15 days. The duplex echo Doppler technique (Aloka 7.5 M Hz probe) was used before and during each celiprolol dose period. Statistical analysis was performed by Student's paired t test. It was observed that celiprolol significantly increases the brachial artery diameter in a dose-dependent manner, and also increases the blood flow velocity (not being direct dose-related). Since the increase in diameter was clear with a higher dose, a dose-dependent increase in blood volume, a decrease in peripheral resistance, and an increase in compliance followed. Since the higher dose of celiprolol did not further reduce blood pressure (BP) in comparison to the lower dose, and a dose-dependent increase in arterial diameter and compliance occurred and a vasodilating effect of celiprolol on arterial wall ensued that was not related to BP.In conclusion, in the doses used, celiprolol dilates both arterioles and large arteries, but the mechanism of action needs to be clarified.     

The Effect of Dobutamine without and with L-Arginine on Arterial Compliance in Heart Failure Patients

The effect of dobutamine on carotid and brachial arteries compliance and the association of L-arginine as a potential nitric oxide pathway restorer were evaluated in patients with heart failure. Twenty-seven outpatients participated. Drugs used for the treatment of heart failure were withheld at least 24 hours before the study. The carotid and brachial artery diameters and hemodynamic variables were evaluated by ultrasonography and Doppler in baseline conditions, with dobutamine, with flow-mediated dilatation (FMD), and with placebo or L-arginine alone and associated with dobutamine. There was a significant increase in carotid peak blood flow with dobutamine when compared with that at baseline (P = 0.0001) or with L-arginine or placebo (P = 0.0001 and P = 0.0001, respectively), with increase of the cardiac index (P = 0.0001). Dobutamine did not increase carotid arterial compliance. FMD significantly increased the brachial peak blood flow (P = 0.0022) and the artery diameter (P = 0.0001). Dobutamine did not change the brachial artery diameter. Brachial peak blood flow was increased with dobutamine alone or associated with placebo or L-arginine comparing with L-arginine or placebo alone (P = 0.0168 and P = 0.0140, respectively), but was not increased compared with that at baseline. L-arginine infusion was not associated with changes in carotid, brachial, or in the cardiac index. We concluded that dobutamine increased carotid peak blood flow in patients with heart failure, although without changing the arterial compliance. The FMD of brachial artery was maintained, while brachial artery response to dobutamine infusion was less reliable. The carotid artery may be under the direct influence of the heart, while the brachial artery may be under predominant local control.     

The effect of age on vascular compliance in man: which are the appropriate measures?

Vascular compliance declines rapidly with age and measures of arterial compliance may help understanding of the aging process. Of the different measures of vascular compliance, those more closely related to chronological age need to be identified. These measures may help in the estimation of 'biological age'. We measured pulse wave velocity as the carotid-finger interval, carotid-toe interval and QKD interval (time between the Q wave and the arrival of the diastolic Korotkoff sound (K) over the brachial artery in diastoly (D)); central aortic compliance (CAC) and SV/PP (the stroke volume divided by pulse pressure in the brachial artery). Thirty-six volunteers were studied (30 men), ages 20 to 84, mean 49 years, to give the relationship of these measurements with age. CAC, the QKD interval and the carotid-toe interval were most closely related to age (r = - 0.51, -0.60 and -0.58 respectively). After adjustment for age, the only measure related to blood pressure was the carotid-finger interval; b for diastolic blood pressure = -0.83 (P = 0.01), the higher the pressure the shorter the interval. Measurements of CAC, QKD interval and carotid-toe interval may be employed to assess the impact of age on vascular compliance. Measures of peripheral vascular compliance, such as the carotid-finger interval, may prove useful in assessing the relationship between blood pressure and vascular compliance.     

西拉普利与美托洛尔对高血压前臂动脉功能影响的临床研究

目的：比较西拉普利与美托洛尔长期治疗原发性高血压患者肱动脉功能的影响。方法：脉冲多普勒法。结果：两组原发性高血压患者分别接受西拉普利或美托洛尔治疗6个月后血压均明显下降,但西拉普利组的肱动脉管径、血流速度、血流量和扩张性增加,血流阻力减少;而美托洛尔治疗组的肱动脉管径、血流速度、血流量和扩张性有所下降或无明显改变。结论：西拉普利可以部分改善高血压者前臂动脉功能。     

西拉普利与美托洛尔对高血压前臂动脉功能影响的临床研究

目的比较西拉普利与美托洛尔长期治疗对原发性高血压患者肱动脉功能的影响。 方法脉冲多普勒法。 结果两组原发性高血压患者分别接受西拉普利或美托洛尔治疗6个月后血压均明显下降,但西拉普利组的肱动脉管径、血流速度、血流量和扩张性增加,血流阻力减少;而美托洛尔治疗组的肱动脉管径、血流速度、血流量和扩张性有所下降或无明显改变。 结论西拉普利可以部分改善高血压患者前臂动脉功能     

Auscultatory and oscillometric methods of ambulatory blood pressure monitoring, advantages and limits: a technical point of view

Two methods of indirect blood pressure (BP) measurement are currently used for ambulatory blood pressure measurement (ABPM): the auscultatory and oscillometric methods. The auscultatory method is based on the detection of Korotkoff sounds issued from the acoustic transudcer signal. Its main advantages are (1) similarities with usual clinical measurement of BP; and (2) accurate detection of systolic and diastolic pressures on the appearance and disappearance of sounds. The main disadvantages of this method are (1) artefacts due to movements; and (2) difficulties in signal analysis due to physiological variations of the Korotkoff sound patterns or poor signals. Difficulties can be overcome by appropriate signal processing (K2 recognition), noise rejection and/or ECG gating. This may allow relatively accurate BP measurement during mild exercise. With the oscillometric method, air volume variations in the cuff are detected during deflation. The maximum oscillation is related to the mean arterial pressure. The systolic and diastolic BP are determined by an algorithmic interpretation of the shape of oscillometric amplitudes as well as the heart rate. The main advantages are (1) possibility of BP measurement when the Korotkoff signal is poor; (2) measurement of the mean arterial BP; and (3) no need of a microphonic sensor. The main disadvantages are (1) some oscillometric curves are difficult to read accurately; (2) oscillometry is very sensitive to movements due to the bandwidth of the signals, so the arm must be immobile; and (3) the accuracy of the systolic and diastolic BP depends on the algorithm used. These two methods are complementary and should ideally be associated in the same device.     

Effect of age on brachial artery wall properties differs from the aorta and is gender dependent: a population study

Compliance and distensibility are wall properties of large arteries, which may play a role in cardiovascular disease. The purpose of this study was to investigate whether the influence of age on these vessel wall properties differs between vascular territories and is gender-dependent. In a population sample of 498 men and women 20 to 79 years of age, diameter, distensibility, and compliance coefficient of the muscular brachial artery were measured with an echo-tracking device. Distensibility of the aorta was measured with the use of pulse-wave velocity. The effects of age and gender were assessed and adjusted for confounding factors such as mean blood pressure, pulse rate, body mass index, smoking, alcohol intake, and antihypertensive treatment. Covariance analysis showed no relation between gender and distensibility of the elastic aorta. Distensibility of the muscular brachial artery was lower in men, whereas men had a larger diameter and larger compliance of the brachial artery. With age, distensibility of the aorta decreased in both sexes to the same extent, whereas distensibility of the brachial artery did not change significantly. With age, brachial artery diameter increased; this increase was more pronounced in women. In men brachial artery compliance did not change with age, whereas in women compliance of the brachial artery increased with age. This study (1) confirms that distensibility of the aorta, an elastic artery, decreases with age. (2) In contrast to the aorta, after adjustment for confounding factors, in both men and women, no relation exists between age and distensibility of the muscular brachial artery. (3) Brachial artery diameter increase with age is more pronounced in women than in men. (4) In contrast to the well-known decrease in arterial compliance of elastic arteries with age, brachial artery compliance is not decreased with age and is increased in women. In conclusion, the effect of age on large-artery wall properties is not uniform but depends on gender and vascular territory.     

Relation between digital peripheral arterial tonometry and brachial artery ultrasound measures of vascular function in patients with coronary artery disease and in healthy volunteers

Digital peripheral arterial tonometry (PAT) is an emerging, noninvasive method to assess vascular function. The physiology underlying this phenotype, however, remains unclear. Therefore, we evaluated the relation between digital PAT and established brachial artery ultrasound measures of vascular function under basal conditions and after reactive hyperemia. Using a cross-sectional study design, digital PAT and brachial artery ultrasonography with pulsed wave Doppler were simultaneously completed at baseline and after reactive hyperemia in both those with established coronary artery disease (n = 99) and healthy volunteers with low cardiovascular disease risk (n = 40). Under basal conditions, the digital pulse volume amplitude demonstrated a significant positive correlation with the brachial artery velocity-time integral that was independent of the arterial diameter, in both the healthy volunteer (r(s) = 0.64, p <0.001) and coronary artery disease (r(s) = 0.63, p <0.001) cohorts. Similar positive relations were observed with the baseline brachial artery blood flow velocity and blood flow. In contrast, no relation between the reactive hyperemia-evoked digital PAT ratio and either brachial artery flow-mediated dilation or shear stress was observed in either cohort (p = NS). In conclusion, these findings demonstrate that the digital PAT measures of vascular function more closely reflect basal blood flow in the brachial artery than reactive hyperemia-induced changes in the arterial diameter or flow velocity, and the presence of vascular disease does not modify the physiology underlying the digital PAT phenotype.     

Effect of posture on arterial pressures, timing of the arterial sounds and pulse wave velocities in the extremities.

We have recorded systolic and diastolic blood pressure, and the intervals between the QRS complex of the electrocardiogram and the Korotkoff arterial sound at systolic and diastolic pressure (QKs and QKd, respectively), at the brachial and posterior malleolar arteries, for normal subjects in the supine, standing, or head-down positions on a tilt table. These data make it possible to calculate an apparent mean pulse wave velocity. Results indicate: (1) when the subject is supine (0 degrees), brachial and posterior malleolar artery blood pressures are virtually identical; (2) upon standing (+90 degrees), both systolic and diastolic pressures in the foot are elevated by a mean of approximately 70 mm Hg, whereas brachial artery systolic pressure is unaffected and brachial diastolic pressure is raised 7 mm of mercury; (3) conversely, in the head-down (feet-up) position (-30 degrees) the blood pressure in the foot was decreased approximately 20 mm of mercury, whereas the brachial arterial pressure is again unaffected; (4) as one changes from the head-down to the supine to the standing positions, the mean QKs interval at the brachial artery was increased by 5 and 15 msec, respectively; (5) conversely, the arrival of the pulse wave in the leg was hastened, with QKd decreasing by 7 and then 18 msec. The effects of QKs were slightly smaller in the brachial artery but considerably larger in the malleolar artery, with a decrease of 16 msec and then 48 msec; (6) mean apparent pulse wave velocity increases from 9.1 to 10.9 to 17.6 m/sec, as one changes from -30 degrees to 0 degrees to +90 degrees.     

Intrinsic (isobaric) effect of essential hypertension on visco-elastic properties of the brachial artery

The purpose of this study was to estimate the effect of hypertension on the visco-elastic properties of the brachial artery in man. Seventy-five subjects including 23 with normal blood pressure (group N, PN = 95 +/- 7 mmHg, P designates the arterial mean pressure, P = DBP + (SBP-DBP)/3) and 52 with essential hypertension (group H, PH = 122 +/- 12 mmHg) participated to this study. We measured the diameter of the brachial artery (D) by the pulsed Doppler method, the brachial-radial pulse wave velocity (PWV) by the mecanographic method, and calculated the arterial compliance (C) by the Bramwell-Hill formula. A nonlinear model was used to calculate compliance and pression at any given pressure, in particular at PN or PH. We obtained the following results: [table; see text] Passive (pressure-induced) effect was obtained by comparing D(PH) to D(PN) and C(PH) to C(PN). Isobaric effect of hypertension was estimated by comparing D(PH) and C(PN) between the N and H groups. We concluded that hypertension actually induces a decrease in compliance. However, arterial diameter is increased in hypertension. The increase in diameter appears as a compensatory effect, without which the reduction in compliance would be more nocive to the circulatory system.     

Large artery function in patients with chronic heart failure. Studies of brachial artery diameter and hemodynamics

BACKGROUND. Although progressive chronic congestive heart failure (CHF) is associated with elevated systemic vascular resistance and increased impedance to ventricular outflow, the contribution of changes in large artery function has not been well documented in humans. METHODS AND RESULTS. We studied 45 patients with a broad range of clinical severity of CHF and compared noninvasive measurements of brachial artery diameter, flow, and pulse wave velocity with 22 normal controls of similar age. In CHF, mean arterial pressure was lower than in controls (85 +/- 1 versus 93 +/- 2 mm Hg, p less than 0.001), as were brachial artery diameter (4.07 +/- 0.10 versus 4.53 +/- 0.09 mm, p less than 0.001), flow (40.9 +/- 4.1 versus 70.9 +/- 11.5 ml.min-1, p less than 0.02), compliance (1.29 +/- 0.12 versus 2.00 +/- 0.18 cm4.dyne-1.10(-7), p less than 0.002), and conductance (0.49 +/- 0.05 versus 0.76 +/- 0.13 units, p = 0.06). Limb vascular resistance (40.2 +/- 5.0 versus 20.5 +/- 3.1 units, p less than 0.001) and pulse wave velocity (10.6 +/- 0.5 versus 9.2 +/- 0.4 m.sec-1, p less than 0.03) were higher than in controls. Brachial artery diameter was progressively lower than in controls as severity of CHF increased (New York Heart Association class II, 4.47 +/- 0.23 mm, p = NS; class III, 4.05 +/- 0.10 mm, p less than 0.05; class IV, 3.71 +/- 0.28 mm, p less than 0.05). Similar changes were observed for arterial compliance (class II, 1.76 +/- 0.32 cm4.dyne-1.10(-7), p = NS; class III, 1.21 +/- 0.13 cm4.dyne-1.10(-7), p less than 0.05; class IV, 0.95 +/- 0.10 cm4.dyne-1.10(-7), p less than 0.05). While the lower arterial pressure and flow might be expected to passively reduce arterial diameter, this would be associated with a reduced pulse wave velocity and improved arterial compliance, yet the opposite was observed. Differences in large artery function were not likely caused by underlying atherosclerosis alone, because patients with dilated cardiomyopathy and patients with ischemic heart disease of the same sex, age, left ventricular ejection fraction, and exercise treadmill duration had similar changes in large artery function. CONCLUSIONS. We conclude that alterations in brachial artery function are present in patients with moderate and severe CHF. The observed reduction in arterial compliance, if present diffusely throughout the arterial tree, could increase left ventricular end-systolic stress directly and through increased velocity of reflected pressure waves from the periphery.     

Conventional ultrasonography Doppler in the assessment of arterial peripheral circulation

Ultrasonography Doppler in the assessment of arterial peripheral circulation. PURPOSE: The ultrasonography-Doppler study of peripheral arterial circulation requires measurements of arterial area and arterial blood flow. The aim of this study was to assess their variabilities, intra- and interobserver. METHODS: We studied brachial arterial circulation of 13 volunteers. Two experimented investigators carried out the examinations. Arterial blood pressure measurements were obtained at the level of the brachial artery of the left arm by means of a semi automated oscillometric device. The brachial artery was approached by ultrasound scan in semi-decubitus position, the arm in exterior rotation and abduction. Brachial artery cross-sectional areas were obtained by a transversal view with a depth of 4-15-cm upstream the antecubital fossa of the forearm. Cross sectional areas were measured at end diastole (SD) and end systole (SS). We measured maximal systolic and diastolic velocities (Vmax and Vmin), mean velocity (Vmoy) and velocity integral (ITV) of the blood flow. We deduced brachial output (D), resistance and pulsatility index (IR, IP), cross-sectional compliance coefficient (C). RESULTS: Intra- and interoperator variability as assessed by the Bland-Altman approach was acceptable SS, SD, ITV, D, Vmax, Vmoy, Vmin C, IR, and IP, in regard with values of variation coefficient, biais, and concordance limits. CONCLUSION: Conventional B-mode ultrasonography may offer a reliable method for arterial peripheral circulation evaluation.