It has been found that the incidence of cardiovascular disease in patients with lower limb amputation is significantly higher than that in normal individuals, but the relationship between lower limb amputation and the episodes of cardiovascular disease has not been studied from the perspective of hemodynamics. In this paper, numerical simulation was used to study the effects of amputation on aortic hemodynamics by changing peripheral impedance and capacitance. The final results showed that after amputation, the aortic blood pressure increased, the time averaged wall shear stress of the infrarenal abdominal aorta decreased and the oscillatory shear index of the left and right sides was asymmetrically distributed, while the time averaged wall shear stress of the iliac artery decreased and the oscillatory shear index increased. The changes above were more significant with the increase of amputation level, which will result in a higher incidence of atherosclerosis and abdominal aortic aneurysm. These findings preliminarily revealed the influence of lower limb amputation on the occurrence of cardiovascular diseases, and provided theoretical guidance for the design of rehabilitation training and the optimization of cardiovascular diseases treatment.
Amputation ; Aorta, Abdominal/surgery* ; Aortic Aneurysm, Abdominal/surgery* ; Blood Flow Velocity/physiology* ; Hemodynamics/physiology* ; Humans ; Lower Extremity ; Models, Cardiovascular ; Stress, Mechanical

By using Doppler sensor and pressure sensor, the cerebrovascular stroke detector can be used to measure the blood flow velocity and blood pressure of the carotid artery. In this study, a variety of signal conversion and isolation processing techniques are proposed for processing and feature extraction of the output signals from the sensors. Finally, effective signal output waveforms that can be used to evaluate the cerebrovascular hemodynamics index (CVHI) are obtained, and the sound signal outputs that can reflect the change characteristics of blood flow velocity and blood pressure signals are generated, which realizes the application functional requirements of the detector.
Blood Flow Velocity/physiology* ; Cerebrovascular Circulation/physiology* ; Hemodynamics/physiology* ; Humans ; Stroke ; Technology

Echocardiogram is vital for the diagnosis of cardiac disease. The heart has complex hemodynamics requiring an advanced ultrasound imaging mode. Cardiac ultrasound vector flow imaging is capable of measuring the actual magnitude and direction of the blood flow velocity, obtaining the quantitative parameters of hemodynamics, and then providing more information for clinical research and diagnosis. This study mainly reviewed several different vector flow imaging techniques for cardiac flow and presented the implementation difficulties, and proposed a diverging wave based high frame rate cardiac ultrasound vector flow imaging. The study discussed the limitation of current ultrasound technology used in the cardiac flow measurement, analyzed and demonstrated the specific reasons for these implementation difficulties and the potential future development.
Blood Flow Velocity ; Heart/physiology* ; Hemodynamics ; Ultrasonography

The radial artery pulse wave contains a wealth of physiological and pathological information about the human body, and non-invasive studies of the radial artery pulse wave can assess arterial vascular elasticity in different age groups.The piezoelectric pulse wave transducers were used to non-invasively acquire radial artery pulse waves at different contact pressures in young and middle-aged and elderly populations. The radial artery waveforms were decomposed using a triangular blood flow model fitting method to obtain forward and reflected waves and calculate reflection parameters. Finally a correlation analysis and regression analysis of the contact pressure P_sensor with the reflection parameters was carried out. The results showed that the reflection parameters RM, RI and R_d had a strong negative correlation with P_sensor in both types of subjects, and the correlation coefficients and slopes of the regression curves were significantly different between the two types of subjects (P<0.05). Based on the results of this study, excessive contact pressure on the transducer should be avoided when detecting radial artery reflection waves in clinical practice. The results also show that the magnitude of the slope of the regression curve between the reflection parameters and the transducer contact pressure may be a potentially useful indicator for quantifying the elastic properties of the vessel.
Middle Aged ; Aged ; Humans ; Blood Pressure/physiology* ; Arteries ; Blood Flow Velocity/physiology* ; Elasticity ; Pulse Wave Analysis ; Radial Artery/physiology*

OBJECTIVE: To determine the feasibility of ultrasound to measure blood flow on patients with chest compression cardiopulmonary resuscitation (CPR), and to find out a real-time, noninvasive hemodynamic evaluation method. METHODS: A prospective study was conducted. All adult patients undergoing CPR admitted to Department of Emergency and intensive care unit (ICU) of Zhengzhou People's Hospital from May 2016 to November 2018 were enrolled. The blood flow over the right carotid arteries during chest compressions was recorded with a bedside ultrasound machine. The peak systolic flow velocity (PSV) and end diastolic flow velocity (EDV) of carotid artery were recorded at 1 minute after the start of CPR and 1 minute before the end of CPR. The mean compression frequency during the whole recovery period was recorded, the rate of compression reaching the standard was evaluated by ultrasound (the rate of compression 100-120 times/min was defined as up to standard), and the interruption time of compression was calculated retrospectively according to the ultrasound image data recorded during CPR. RESULTS: Thirty-nine patients were enrolled, and 21 patients were successfully rescued, with a successful rate of 53.8%, the time of restoration of spontaneous circulation (ROSC) was (10.9±5.3) minutes. The time from CPR to retrieve an ultrasound image was 1.1-4.9 minutes, with an average of (2.5±1.2) minutes. Satisfactory ultra-sonographic images were obtained in 28 patients during the whole course of chest compression. The acquisition rate was 71.8% (28/39). In the process of compression, if the frequency of compression was less than 100 times/min or the velocity of carotid artery dropped (PSV < 30 cm/s), the chest compressors should be reminded and corrected in time. The PSV at 1 minute after CPR start of 28 patients with satisfactory ultrasound images was (62.9±18.5) cm/s, and the EDV was (13.9±3.5) cm/s, the PSV at 1 minute before the end of CPR was (55.4±18.4) cm/s, and the EDV was (12.9±3.7) cm/s. There was no significant difference in above parameters between the two time points (both P > 0.05), suggesting that satisfactory resuscitation effect was achieved in the whole process of CPR. The compression frequency of 28 patients was 100-149 times/min with an average of (117±47) times/min. The rate of compression with standard was 85.7% (24/28), and the total interruption time of compression accounted for 4.4% of all compression time (25.9 minutes/587.2 minutes). CONCLUSIONS Ultrasound measurement of common carotid artery blood flow during CPR has the advantage of real-time and non-invasive, and it is feasible in clinical work.
Adult ; Blood Flow Velocity/physiology* ; Cardiopulmonary Resuscitation/methods* ; Carotid Artery, Common/physiology* ; Feasibility Studies ; Humans ; Pressure ; Prospective Studies ; Retrospective Studies ; Ultrasonography, Doppler

To investigate hemodynamic parameters in 2 anatomical segments (S1 and S2) of anterior cerebral artery (ACA) in normal pregnancy during the second and third trimester of gestation.
 Methods: The peak systolic velocity (PSV), end diastolic velocity (EDV), time-average maximum velocity (TAMAXV), peak systolic velocity/end diastolic velocity (S/D), resistance index (RI), and pulsation index (PI) in S1 and S2 of fetal anterior cerebral artery (ACA) in 288 normal pregnant women were detected by power Doppler and pulsed Doppler. Multiple regression models were fitted to estimate the relation between Doppler variables and gestational age. The differences of hemodynamic parameters between ACAS1 and ACAS2 were compared.
 Results: The PSV, EDV, and TAMAXV of ACAS1 and ACAS2 were positively correlated with the weeks of pregnancy (P<0.001), all fitted with the cubic curve. The S/D, PI, and RI values of ACAS1 and ACAS2 were not correlated with gestational ages (P>0.05). The PSV, TAMAXV, S/D, PI, and RI of ACAS1 were significantly higher than those of ACAS2, while EDV in ACAS1 was lower than that in ACAS2 (P<0.05).
 Conclusion: The velocity parameters (PSV, EDV, TAMAXV) of the 2 anatomical segments (ACAS1 and ACAS2) are increased with the increase of gestational age in normal pregnant fetus during the second and third trimester of gestation, and the resistance parameters (S/D, PI, RI) are not significantly correlated with gestational age. Distribution of blood flow is different in the blood supply territory between ACAS1 and ACAS2.
Anterior Cerebral Artery ; physiology ; Blood Flow Velocity ; Female ; Fetus ; blood supply ; Hemodynamics ; Humans ; Pregnancy ; Pregnancy Trimester, Third ; Ultrasonography, Prenatal

To study the blood flow parameters for 2 anatomical segments of posterior cerebral artery (PCA) in normal singleton fetal.
 Methods: The blood flow velocity parameters peak systolic velocity (PSV), end diastolic velocity (EDV), time-average maximum velocity (TAMAXV), velocity time integral (VTI) and resistance parameters systolic peak velocity and end diastolic velocity ratio (S/D), pulsatility index (PI), resistance index (RI) for 2 anatomical segments in PCA were recorded. The first segment of the PCA (PCAS1) was recorded between the origin of PCA and the proximal part of the posterior communicating artery. The second segment of the PCA (PCAS2) was recorded at the distal part of the posterior communicating artery. The blood parameters in both PCAS1 and PCAS2 were analyzed by using Pearson correlation and multiple curves fitting with gestational age (GA). Paired student's t test was performed to compare the difference in blood parameter between PCAS1 and PCAS2.
 Results: The blood flow velocity parameters in both PCAS1 and PCAS2 were increased with the GA (P<0.0001), with the best fitted curves of Quadratic curve (P<0.0001). There were no correlations between resistance parameters in PCA and GA (P>0.05). Resistance parameters in PCAS1 were higher than those in PCAS2 (P<0.05).
 Conclusion: The blood flow velocity parameters in both PCAS1 and PCAS2 are increased with GA. The resistance parameters in both PCAS1 and PCAS2 do not change with GA. Study on the velocities and resistance in these 3 arterial branches provides a more comprehensive evaluation on the process of brain circulation.
Blood Flow Velocity ; physiology ; Diastole ; physiology ; Female ; Gestational Age ; Hemodynamics ; physiology ; Humans ; Posterior Cerebral Artery ; physiology ; Pregnancy ; Systole ; physiology

OBJECTIVETo explore the pattern of variations in middle cerebral artery peak systolic velocity (MCA PSV) and cardiothoracic ratio (CTR) during early pregnancy, establish their reference ranges and explore their correlation with the crown-rump length (CRL).

METHODSA total of 522 pregnant women with normal findings in antenatal examinations underwent routine color Doppler ultrasound examination to collect the data of MCA PSV, CTR and CRL. The reference ranges of MCA PSV and CTR for different CRL levels were established, and the correlation of MCA PSV and CTR with CRL was analyzed.

RESULTSDuring the first trimester, MCA PSV and CRL showed a moderate positive correlation with a correlation coefficient of 0.426 (P<0.001), while CTR and CRL showed no significant correlation (0.168, P<0.001). The reference range of MCA PSV was 14.35 (14.08-14.62) cm/s and that of CTR was 0.34 (0.33-0.34) during early pregnancy.

CONCLUSIONColor Doppler ultrasound is a safe and feasible modality to assess fetal MCA PSV and CTR for detecting fetal growth abnormalities in early pregnancy. The established reference ranges of MCA PSV and CTR offer a clinical theoretical basis for detecting α-thalassemia in early pregnancy.

Blood Flow Velocity ; Crown-Rump Length ; Female ; Fetal Diseases ; diagnostic imaging ; Humans ; Middle Cerebral Artery ; physiology ; Pregnancy ; Pregnancy Trimester, First ; Reference Values ; Systole ; Ultrasonography, Doppler, Color ; Ultrasonography, Prenatal

OBJECTIVETo investigate renal artery injury caused by Kawasaki disease (KD).

METHODSForty-three children with KD were enrolled in the study. According to the blood pressure in the acute stage, these children were classified into normal blood pressure subgroup and increased blood pressure subgroup. Eighteen children with fever caused by acute upper respiratory tract infection were enrolled as the control group. The diameter of the origin of the main renal artery, hemodynamic parameters of the main renal artery and the renal interlobar artery, rennin activity, and levels of angiotensin II and aldosterone were compared between groups.

RESULTSDuring the acute stage of KD, both subgroups had a significantly smaller diameter of the origin of the main renal artery, a significantly higher resistance index (RI) of the main renal artery, and a significantly lower end-diastolic velocity (EDV) than the control group (P<0.05).The increased blood pressure subgroup had a significantly lower EDV of the interlobar artery than the normal blood pressure subgroup, a significantly higher RI than the normal blood pressure subgroup and the control group, as well as a significantly higher rennin activity and significantly higher levels of angiotensin II and aldosterone than the normal blood pressure subgroup (P<0.05). A significantly increased EDV and a significantly reduced RI of the renal interlobar artery were observed in the increased blood pressure subgroup in the subacute stage compared with the acute stage (P<0.05).

CONCLUSIONSKD may cause renal artery injury and early hemodynamic changes, resulting in a transient increase in blood pressure in some patients.

Blood Flow Velocity ; Blood Pressure ; Child, Preschool ; Female ; Humans ; Infant ; Male ; Mucocutaneous Lymph Node Syndrome ; physiopathology ; Renal Artery ; physiopathology ; Renin-Angiotensin System ; physiology ; Vascular Resistance

PURPOSE: Despite technical simplicity and the low cost of brachial-ankle pulse wave velocity (BA-PWV), its use has been hampered by a lack of data supporting its usefulness and reliability. The aim of this study was to evaluate the usefulness of BA-PWV to measure aortic stiffness in comparison to using cardiovascular magnetic resonance (CMR). MATERIALS AND METHODS: A total of 124 participants without cardiovascular risk factors volunteered for this study. BA-PWV was measured using a vascular testing device. On the same day, using CMR, cross-sectional areas for distensibility and average blood flow were measured at four aortic levels: the ascending, upper thoracic descending, lower thoracic descending, and abdominal aorta. RESULTS: Compared to PWV measured by CMR, BA-PWV values were significantly higher and the differences therein were similar in all age groups (all p<0.001). There was a significant correlation between BA-PWV and PWV by CMR (r=0.697, p<0.001). Both BA-PWV and PWV by CMR were significantly and positively associated with age (r=0.652 and 0.724, p<0.001). The reciprocal of aortic distensibility also demonstrated a statistically significant positive correlation with BA-PWV (r=0.583 to 0.673, all p<0.001). CONCLUSION: BA-PWV was well correlated with central aortic PWV and distensibility, as measured by CMR, regardless of age and sex.
Adult ; Ankle Brachial Index/*methods ; Ankle Joint ; Aorta/anatomy & histology/*physiology ; *Blood Flow Velocity ; Cardiovascular Diseases ; Female ; Heart/physiopathology ; Humans ; *Magnetic Resonance Imaging, Cine ; Male ; Pulse Wave Analysis/*methods ; Regional Blood Flow ; Reproducibility of Results ; Risk Factors ; *Vascular Stiffness