Elevation of brachial arterial blood velocity and volumic flow mediated by peripheral beta-adrenoreceptors in patients with borderline hypertension

Simultaneous determinations of cardiac output and brachial arterial blood flow were performed in patients with hypertension and high cardiac output in comparison with normal subjects of the same age. Brachial arterial blood flow was measured with a previously described pulsed Doppler apparatus that permitted the noninvasive determination of arterial diameter and blood flow velocity. In patients with borderline hypertension, brachial blood flow was significantly increased (136 +/- 11 vs 72 +/- 8 ml/min; p less than .001). After short-term administration of indomethacin, cardiac output decreased while brachial blood flow remained constant. After short-term administration of a selective beta 1-receptor antagonist (primidolol) and nonselective blocker (propranolol), cardiac output decreased significantly in both cases but the decrease in brachial blood flow was significant only after the administration of the nonselective beta-blocking agent. The study strongly suggested that in patients with borderline hypertension, the increased cardiac output is related to a prostaglandin and beta 1-adrenergic mechanisms whereas the increased brachial blood flow depends mainly on beta 2-adrenergic mechanisms.     

Effect of arterial hypertension on pulse wave velocity and the diameter and compliance of the brachial artery in man

The non invasive investigation of the brachial artery was performed in 51 mild to moderate essential hypertensive patients and 23 normal subjects of similar age. It included quantitative evaluation of arterial diameter (pulsed Doppler velocimetry), pulse wave velocity (strain gauge mechanography) and arterial compliance deduced from the former indices. Hypertensive patients exhibited higher pulse wave velocity (Pw 0.001) and arterial diameter (p less than 0.01) than normal controls. The strong correlation found in normal subjects between pulse wave velocity and the product of age and diastolic pressure (r = 0.88, p less than 0.001) was used as a nomogram for the analysis of those hypertensive arterial changes. Accordingly the projection of patients on this nomogram enables to distinguish two groups according to that pulse wave velocity was inside (Group 1) (37 patients) or above (Group II) (34 patients) the upper limit of the nomogram. The comparison of these two groups of hypertensive patients showed that despite a similar level of age and pressure, arterial compliance was lower and pulse pressure higher in Group II than in Group I. These results demonstrate that early alterations of brachial artery occur in hypertension: these arterial changes can be attributed in most of the patient to the exclusive effect of aging and pressure elevation; however, in some patients additional degenerative process, perhaps atherosclerotic in nature, is responsible for profound decrease in arterial compliance and increase in pulse pressure so that such patients may appear as especially predisposed to systolic hypertension and degenerative arterial complications.     

彩色多普勒血流显像测量同侧肱动脉血流速预测自体动静脉内瘘成熟度的研究

目的 探讨彩色多普勒血流显像(CDFI)测量同侧肱动脉血流速与自体动静脉内瘘（AVF）成熟的相关性。方法 选择2015年12月～2018年8月于我院行头静脉-桡动脉端侧吻合且术后触诊震颤明显的患者141例,收集其临床资料,对AVF前后CDFI检查结果进行比较。结果 141例患者中有116例患者内瘘成熟（成熟组）,25例内瘘成熟不良（成熟不良组）。成熟不良组患者糖尿病患病率和糖尿病肾病为原发病的比例高于成熟组（P＜0.05）;成熟组患者术前头静脉直径大于成熟不良组（P＜0.05）;内瘘成熟组患者术后8周瘘口直径、肱动脉直径、肱动脉最大血流速和肱动脉血流速变化均高于成熟不良组（P＜0.05）。结论 术后早期采用CDFI测定肱动脉直径、肱动脉最大血流速及肱动脉流速变化可预测内瘘是否成熟,用于早期发现内瘘成熟不良。     

Transluminal, subselective measurement of coronary artery blood flow velocity and vasodilator reserve in man

Assessment of coronary blood flow and the vasodilator reserve capacity of individual coronary arteries in the catheterization laboratory has been hampered by methodologic limitations. We have developed and validated a small Doppler catheter that can subselectively measure phasic coronary blood flow velocity (CBFV). In seven anesthetized calves, CBFV was varied from 0.1 to 5.7 times control CBFV. Changes in mean CBFV measured intraluminally by catheter in the left anterior descending and left circumflex arteries were similar to those measured simultaneously with an epicardial Doppler probe on the surface of the same vessel (n = 85, r = .95, slope = 1.04) and to changes in coronary sinus flow (n = 69, r = .97, slope = 1.06) measured with timed venous collections. Identical maximal coronary reactive hyperemic responses with the catheter present and absent in the artery being studied demonstrated that coronary obstruction by the catheter was minimal. Safety studies in six additional calves demonstrated that the catheter caused small changes in coronary endothelial permeability. Histologic studies revealed no endothelial denudation or thrombus formation. Stable phasic recordings of coronary blood flow velocity have been obtained in 58 of 70 patients studied. One of the 70 patients studied had abrupt coronary occlusion probably related to catheter-induced vasospasm. In 10 normal patients, intracoronary meglumine diatrizoate increased CBFV to 3.5 times that at rest (range 2.8 to 5.0). CBFV rose 5.0-fold after an intravenous infusion of dipyridamole (range 3.8 to 7.0). In each patient, dipyridamole produced greater vasodilation than meglumine diatrizoate. The time- and dose-response characteristics to dipyridamole infusion were heterogeneous, underscoring the advantage of continuous on-line measurement of CBFV in the measurement of vasodilator reserve. This method of measuring CBFV and assessing vasodilator reserve in the catheterization laboratory should facilitate studies of the coronary circulation in man.     

Hemodynamic factors changing blood flow velocity waveform and profile in normal human brachial artery

We have investigated the influence of changes of perfusion pressure and local peripheral resistance on blood flow velocity waveform and profile in normal human peripheral arteries. Blood flow velocity and profile were recorded from the distal end of the left brachial artery in ten normal subjects by means of an ultrasonic device. The records were obtained in basal conditions and after blood pressure in the brachial artery and local peripheral vascular resistance were changed, separately or together, by progressive inflation of two arm cuffs, one encircling the proximal half of the left arm and the other the middle part of the left forearm. Both blood flow velocity waveform and profile were shown to be markedly modified by changes in perfusion pressure and local peripheral vascular resistance. Reduction of perfusion pressure decreased both forward and reverse peak velocities, but had the largest effect upon reverse velocity. The upslope and the downslope of the forward velocity wave were left unchanged. Increase in local peripheral vascular resistance markedly augmented reverse peak velocity, whether perfusion pressure was normal or reduced. Increased resistance only slightly influenced peak forward velocity.     

Left ventricular blood flow velocity in man studied with the Doppler ultrasonic flowmeter

Left ventricular blood flow velocity was recorded in 32 conscious human subjects with the Doppler ultrasonic flowmeter catheter. There are three major left ventricular flow velocity patterns in man: (1) Inflow tract blood velocity is characterized by a predominant diastolic wave related to left ventricular filling succeeded by a smaller systolic component, (2) Midcavity blood flow velocity is triphasic in nature, and (3) Outflow tract blood velocity is manifested by a major systolic wave, resulting from left ventricular ejection.These flow velocity wave-forms parallel the major hemodynamic events occurring at each anatomic site.It is concluded that such study is of value for characterizing blood velocity in the left ventricle of conscious man.     

Transcutaneous Doppler ultrasound measurement of superior mesenteric artery blood flow in man.

A duplex scanner which consists of a real time two dimensional scanner and a pulsed Doppler flowmeter was used to measure superior mesenteric blood flow in 70 healthy subjects. By processing the Doppler shift signals, the instantaneous average Doppler shift frequency and then the instantaneous average velocity of the flow rate were calculated. Both diameter of the vessel and angle between vessel and beam were measured from real time imaging. The mean (+/- standard error of the mean) of the superior mesenteric blood flow was 517 +/- 19 ml/min. There was neither significant difference in flow between sexes, nor correlation between flow and age (r = 0.042). The mean of coefficients of variability were 6.8% over the short term, and 8.2% in long term studies.     

Portal blood velocity and flow in aging man

The portal blood velocity and flow were measured by means of pulsed echo-Doppler in 60 normal subjects of 4 different age groups (less than or equal to 40, 41-55, 56-70, greater than or equal to 71 years). All subjects had normal routine liver function tests and no history of liver disease. Portal blood velocity decreased from 15.7 +/- 3.2 cm/s in younger subjects to 12.4 +/- 1.7 in subjects over 71 years (ANOVA: p = 0.005). Similarly portal blood flow decreased (p = 0.025). Both portal blood velocity and flow were inversely correlated with age (r = -0.583 and -0.505, respectively). No changes in portal vein diameter were observed. The age-related decline in portal flow may account for the decrease in hepatic blood flow previously documented in the elderly.     

Doppler study of phasic variations of blood flow velocity in the anterior interventricular artery

Studies of changes in coronary blood flow during cardiac cycles may be a useful adjuvant to the measurement of coronary flow reserve to evaluate the hydraulic severity of coronary arterial stenoses. We used intracoronary pulsed Doppler velocimetry to measure phasic variations of blood flow in the anterior interventricular artery of 12 patients with angiographically identified stenosis of that vessel. The Doppler signal was obtained by means of a 20 MHz emission from a source placed at the tip of a catheter selectively positioned at the ostium of the anterior interventricular artery, upstream of the stenosis. The increase in severity of stenosis was paralleled by a relative decrease of diastolic blood flow velocity in relation to systolic blood flow velocity. The diastolic/systolic maximum velocities ratio was greater than 1 in 6 patients with a less than 70 p. 100 stenosis (group A) and inferior to 1 in 6 other patients with a 70 p. 100 or more stenosis (group B). In 5 patients of group B this ratio was reversed to normal after percutaneous transluminal angiography. Thus, measurement of intracoronary blood flow velocity may be helpful to evaluate the severity of stenosis, notably in the anterior interventricular artery where angiographic evaluation is difficult.     

Doppler flow velocity determination in the lower extremities

The clinical application of Doppler velocity measurement is reviewed as a diagnostic tool in arterial disease of the lower extremity. Emphasis is placed on the importance of quantitative evaluation of the recorded tracings. Various aspects of qualitative, semi-quantitative and quantitative evaluation are discussed. Included are also some more special applications as pedal arch examination, profunda femoris and penile arteries velocity evaluation.     

Coronary artery blood flow velocity non-invasively measured using a vessel-tracking pulsed Doppler system

A newly-developed noninvasive method was used to measure left coronary blood flow during phantom experiments. Two techniques were used in which: (1) the sample position can always be set in a fluctuating vessel using a wall echo-tracking method with a phase-locked-loop, and (2) the Doppler reference signal was generated separately synchronous with the wall echo signal. These techniques were combined, using a commercially available pulsed Doppler apparatus (SSH-40B: Toshiba). Basic experiments were performed using a blood vessel phantom to verify the validity of these systems. Blood flow velocity in the fluctuating tube could be measured clearly using a vessel-tracking method. The blood flow velocity of the left anterior descending artery was measured in three normal subjects and in seven patients from the third intercostal space along the left sternal border. The velocity pattern was characterized by a crescendo-decrescendo shape in diastole. The peak velocity which appeared in diastole ranged from 19 to 69 cm/sec, with no difference by disease entity. However, in all cases, the blood flow velocity signals were marred by extraneous signals, making it impossible to measure blood flow velocity during systole. Further improvement of the system is mandatory in order to use this flowmeter clinically.     

Doppler blood velocity in the pulmonary artery of infants, children, and adults

A pulsed, range gated, directional, ultrasonic, Doppler blood velocity meter was used to record signals from the pulmonary artery in 52 normal subjects ranging in age from less than 1 week to over 30 years. Signals were obtained from an unfocused transducer in the second or third left intercostal space using a 2.25 MHz instrument. The increase in mean velocity at the start of systole followed a linear pattern for at least the first 45 ms of ejection, irrespective of the age or size of the subject. The value for the acceleration at the start of systole decreased during childhood, reaching less than half that in the aorta in adults, and the duration of the linear increase in velocity increased. The pulmonary arterial signals in newborn infants closely resembled those in the aorta. The range of frequencies seen in the sample volume in the adult pulmonary arterial signals was greater than that in the aorta, whereas in infants it was indistinguishable from that in the aorta.     

Brachial artery blood flow velocity pattern in patients with congestive heart failure: duplex Doppler ultrasonographic assessment

The purpose of this study was to determine whether there are abnormalities in blood flow velocity pattern of the brachial artery in patients with congestive heart failure (CHF). Brachial artery blood flow velocities were measured with duplex Doppler ultrasonography in 12 normal subjects, 31 patients with congestive heart failure (CHF), and 26 patients with coronary artery disease (CAD). None of the patients had clinical evidence of arterial disorders at upper extremities. In both patient groups, the presence of hypertension was correlated with the peak systolic velocity (r=0.48, p<0.05). Patients with heart failure had significantly larger (p<0.0001) peak reverse velocity (20 +/- 6 m/sec) than healthy subjects (5 +/- 4 m/sec) and patients with CAD (7 +/- 3 m/sec). Peak reverse velocity did not differ significantly between normal subjects and CAD group. These data indicate that the blood flow velocity pattern at brachial artery is abnormal in CHF. The simple measurement of brachial artery flow velocity suggests changes in peripheral vasculature related to CHF.     

Aortic blood flow velocity during Wenckebach periods in man

By means of the Doppler ultrasonic flowmeter catheter, phasic aortic blood flow velocity and simultaneous aortic pressure, right atrial pressure, and Lead II of the electrocardiogram were measured in 7 normal subjects and 8 patients with heart disease during right atrial pacing. At pacing rates between 110 and 170 per minute, type I, second-degree atrioventricular block appeared. The increase in peak aortic blood flow velocity was generally proportional to the preceding cycle length and inversely related to the P-R interval. These variations were more pronounced during shorter Wenckebach periods. The first beat of a period always manifested a greater peak flow velocity than did the last beat. Short cycle lengths with less ventricular diastolic filling resulted in diminished aortic systolic flow velocity, with reduction up to 80 per cent. The changes in flow velocity paralleled the changes in aortic pressure.     

Role of transmitral blood flow velocity by Doppler echocardiography in the evaluation of coronary artery disease

To determine the relation between presence and severity of coronary artery disease and diastolic filling abnormalities by Doppler echocardiography, recordings of transmitral inflow velocity were made at rest in 90 patients with coronary artery disease and 28 normals. At the time of the Doppler examination, 81 patients with coronary artery disease (90%) and 10 normals (36%) were treated with antianginal medications. No difference was found in the ratio between early (E) and late (A) diastolic filling velocity (E/A ratio) when comparing patients with greater than 70% obstruction of at least one coronary artery to age-matched normals, regardless of the presence or absence of wall motion abnormalities. The E/A ratio was 1.3 +/- 0.46 in coronary patients with normal wall motion, 1.2 +/- 0.47 in coronary patients with abnormal wall motion, and 1.3 +/- 0.53 in both samples of age-matched normals. Multivariate analysis of the relation between E/A ratio and other variables showed that heart rate (F = 24.46, p less than 0.00001) and age (F = 19.51, p less than 0.00001) were significant independent determinants of the E/A ratio, while the presence or severity of coronary artery disease, the presence of hypertension, the magnitude of wall motion abnormalities, and end-diastolic dimension by echocardiography were not. These data suggest that transmitral inflow velocity recordings by Doppler have limited value for the recognition of coronary artery disease, since the E/A ratio is profoundly influenced by other factors, such as heart rate and age.