Vein Blood Flow Research Articles

Simulation Study on Blood Flow Mechanism of Vein in Existence of Different Thrombus Size

Blood velocity is expected to be as a parameter for detecting abnormality of blood such as the existence of thrombus. Proper blood flow in veins is important to ensure effective return of deoxygenated blood to the heart. However, it is much challenging to recognize the vessel condition due to the inability to visualize the thrombus presence in the vessel. The presence of noise in the image obtained from ultrasound scanning is one of the obstructions in recognizing it. Considering the difficulty, this study aims to assess the velocity and vorticity at the vein valve region using Computational Fluid Dynamics (CFD) method. The velocity of blood and the size of valve orifice are considered important parameters in designing the vein since the stenosis and irregularities of velocity in blood vessels are known as the risk factors for thrombus formation. From the simulation, the velocity contour plot of the blood flow can be visualized clearly. The blood distribution was presented using velocity profile while the fluid particles movement was shown by the velocity vector. The low blood velocity clearly shows the low velocity region which reside at the cusps area and at the beginning of the valve leaflets. Therefore, the present study is able to visualize and evaluate the probable location of thrombus development in the blood vessel.

1Pa5-4 Investigation on singular value decomposition filter for extraction of reflected signals from blood flow in veins

1Pa5-4 Investigation on singular value decomposition filter for extraction of reflected signals from blood flow in veins

Study on the effect of different blood flow velocities of pulmonary vein on endocardial microwave ablation of atrial fibrillation.

To cure atrial fibrillation, the maximum ablation depth (⩾ 50∘C) should exceed the myocardial thickness to achieve the effect of transmural ablation. The blood flow of pulmonary vein in the endocardium can cause the change in the myocardial temperature distribution. Therefore, the study investigated the effect of different pulmonary vein blood flow velocities on the endocardial microwave ablation. The finite element model of the endocardial microwave ablation of pulmonary vein was simulated by electromagnetic thermal flow coupling. The ablation power was 30 W and the ablation time was within 30 s. The blood flow in the coupling of fluid mechanics equation and heat transfer equation results in the heat damage. Furthermore, the cause of the different lesion dimensions is the blood flow velocity. The flow velocities were set as 0, 0.02, 0.05, 0.07, 0.12, 0.16, 0.20, 0.25 and 0.30 m/s. When the flow velocities were 0, 0.02, 0.05, 0.07, 0.12, 0.16, 0.20, 0.25 and 0.30 m/s, the maximum ablation depth were 6.00, 5.56, 5.16, 5.12, 5.04, 5.01, 4.98, 4.96 and 4.94 mm, respectively; the maximum ablation width were 12.53, 9.63, 9.23, 9.16, 9.07, 9.05, 8.94, 8.91 and 8.90 mm, respectively; the maximum ablation length were 12.00, 11.61, 8.98, 8.59, 8.37, 8.23, 8.16, 8.06 and 8.04 mm respectively. To achieve transmural ablation, the time was 3, 3, 3, 3, 3, 4, 4, 4, 4 s, respectively when the myocardial thickness was 2 mm; the time was 7, 8, 8, 8, 9, 9, 9, 9, 9 s, respectively when 3 mm; the time was 15, 16, 18, 19, 19, 20, 20, 20, 20 s, respectively when 4 mm. When the velocity increases from 0 m/s to 0.3 m/s, the microwave lesion depth decreases by 1.06 mm. To achieve transmural ablation, when the myocardial thickness is 2 mm, 3 and 4 s should be taken when the velocity is 0-0.12 and 0.12-0.30 m/s, respectively; when the myocardial thickness is 3 mm, 7, 8 and 9 s should be taken when 0, 0-0.07 and 0.07-0.30m/s respectively; when the myocardial thickness is 4 mm, 15, 16, 18, 19, 20 s should be taken when 0, 0-0.02, 0.02-0.05, 0.05-0.12, 0.12 m/s-0.30 m/s.

Ultrasonographic measurement of blood flow of peripheral vein in the upper limb of healthy participants: a pilot study

Ultrasonographic measurement of blood flow of peripheral vein in the upper limb of healthy participants: a pilot study

Vascular effects of combined vacuum interferential therapy in patients with urolithiasis after extracorporeal shock wave lithotripsy

To study the combined vacuum-interference therapy effect on the renal blood flow in patients with urolithiasis after ECSWL. Forty patients aged 33 to 64 years old with urolithiasis after ECSWL were included in the study. Patients were assigned into two groups by simple randomization. Starting the second day after ECSWL, along with drug therapy, the patients of the main group (n=20) received vacuum-interference therapy with the carrier frequency of 5 kHz, frequency range 80-150 Hz, and the vacuum of 0.3-0.4 bar for 15 min daily, 6-8 procedures in total. Patients in the control group (n=20) received antibacterial and anti-inflammatory drug therapy, the same as the main group. To evaluate the severity of impaired renal blood flow due to nephrolithotripsy, we studied renal blood flow by the basic hemodynamic characteristics of renal ultrasound dopplerography (USDG): renal blood flow indices at the level of renal, segmental, interlobar, and arch arteries, including measurement of systolic linear blood flow velocity (Vps) and diastolic blood flow velocity (Vsd), as well as pulsatility index (PI) and resistance index (RI). The ultrasound examination prior to ECSWL revealed a statistically significant increase in all studied parameters. Thus, Vsd in renal arteries was increased by 32.7% (p<0.01) and 17.8% (p<0.05), respectively; in segmental arteries by 14.5% (p<0.05) and 29.5% (p<0.05), respectively; in interlobar arteries by 14.5% (p<0.05) and 29.5% (p<0.05), respectively, and in the arcus arteriosus by 10.7% (p<0.05) and 21.4% (p<0.05), respectively; the renal vein blood flow was within the reference range. When assessing PI in UL patients before lithotripsy, a statistically significant increase in all studied indices was also observed: in the renal arteries by 19.0% (p<0.05), in the segmental arteries by 12.5% (p<0.05), and in the interlobar and arch arteries by 11.6% (p<0.05) and 11.8% (p<0.05), respectively. After the treatment course, the most pronounced change was observed in the patients of the main group, in which all indices differed from the reference values only by 3.5-8.3%. It is important to note an increase in linear velocity in the renal vein by 21.4% (p<0.05), indicating a significant improvement of renal blood flow due to improved venous outflow and increased arterial inflow in the renal arteries. In the control group patients, statistically significant improvement was observed only for systolic and diastolic blood flow velocity, as well as the renal vein blood flow velocity, which increased by 22.1% (p<0.05), 6.3% and 17.8% (p<0.05), respectively; the other parameters remained unchanged. When assessing PI and RI values after the treatment course, the most marked improvement was also observed in the main group of patients, in which all indices were close to the reference values (p<0.05). In the control group patients, the indices were 11.6-14.0% higher than reference values (p<0.05). According to obtained data, it was concluded that vacuum interference therapy has a pronounced vascular effect that promotes an earlier recovery of blood flow and normalization of the kidney function in patients with urolithiasis after extracorporeal lithotripsy and can be recommended for routine clinical practice.

Massage of the Hepatoduodenal Ligament Recovers Portal Vein Flow Immediately after the Pringle Maneuver in Hepatectomy

Introduction: The Pringle maneuver is often used in liver surgery to minimize bleeding during liver transection. Many authors have demonstrated that intermittent use of the Pringle maneuver is safe and effective when performed appropriately. However, some studies have reported that the Pringle maneuver is a significant risk factor for portal vein thrombosis. In this study, we evaluated the effectiveness of portal vein flow after the Pringle maneuver and the impact that massaging the hepatoduodenal ligament after the Pringle maneuver has on portal vein flow. Materials and methods: Patients treated with the Pringle maneuver for hepatectomies performed to treat hepatic disease at our hospital between August 2014 and March 2019 were included in the study (N=101). We divided these patients into two groups, a massage group and nonmassage group. We measured portal vein blood flow with ultrasonography before and after clamping of the hepatoduodenal ligament. We also evaluated laboratory data after the hepatectomy. Results: Portal vein flow was significantly lower after the Pringle maneuver than before clamping of the hepatoduodenal ligament. The portal vein flow after the Pringle maneuver was improved following massage of the hepatoduodenal ligament. After hepatectomy, serum prothrombin time was significantly higher and serum C-reactive protein was significantly lower in the massage group than in the nonmassage group. Conclusion: Massage of the hepatoduodenal ligament is recommended after the Pringle maneuver to immediately recover portal vein flow during hepatectomy allowing us to shorten the declamping time, which may contribute to a reduction in the operation time.

Central and peripheral hemodynamic responses to orthostasis in hypertensive males with chronic venous disorders taking combined therapy with a calcium channel blocker and an angiotensin-converting enzyme inhibitor

Aim . To study the characteristics of central and peripheral hemodynamic responses to orthostasis in hypertensive (HTN) males with chronic venous disorders (CVD) taking combined therapy with a calcium channel blocker (CCB) and an angiotensinconverting enzyme (ACE) inhibitor. Material and methods . In 46 men 30-50 years old with uncontrolled HTN taking antihypertensive therapy, a comparative assessment of the dynamics of systolic blood pressure (SBP), diastolic blood pressure (DBP), peripheral venous pressure (PVP), lumen diameter and area, blood flow velocity of superficial and deep veins of the left leg in response to orthostasis. Venous hemodynamics was studied by duplex ultrasound. PVP was assessed by oscillometry on the thigh and ultrasound of the great superficial vein. A comparative dynamic analysis of these parameters was carried out in patients of two groups: 23 hypertensive patients without CVD and 23 patients with HTN and CVD. CVD was assessed using Comprehensive Energy Assistance Program (CEAP). Orthostasis was performed before and after 14 days of antihypertensive therapy with a combination of CCB and ACE inhibitors. Results . Central and peripheral hemodynamic responses to orthostasis before treatment in patients of both groups was the same — a decrease in SBP, DBP and PVP, expansion of superficial and deep veins, and a decrease in venous blood flow velocity. As a result of treatment, 43 patients achieved the first target office SBP (&lt;140 mm Hg). Of these, there were 21 HTN patients without CVD and 22 patients with CVD. After treatment, most responses to orthostasis in both groups was similar to pre-treatment ones. However, differences were also noted — in both groups, the DBP increased; SBP decreased only in men with CVD. In patients with CVD, the posterior tibial vein (PTV) dilated and blood flow velocity decreased after treatment in response to orthostasis, while in patients without CVD, there was a narrowing of PTV and blood flow acceleration. After treatment, patients with CVD were characterized by a larger diameter and area of the lumen of superficial and deep veins than those without CVD in response to orthostasis. Conclusion . Orthostasis before antihypertensive therapy in patients both with and without CVD is characterized by an identical hemodynamic response — a decrease in SBP, DBP, PVP expansion of superficial and deep veins, and a decrease in venous blood flow velocity. After 14-day antihypertensive therapy, there were differences in hemodynamic response between the study groups. In patients with HTN and CVD, CCB and ACE inhibitors therapy leads to a redistribution of central and peripheral circulation and increases the dilatation of the veins in response to orthostasis.

Reverse blood flow in cervicofacial veins after venous ligations: Potential implications in microsurgery

The consequences on the cervicofacial venous circulation of major cervicofacial vein ligations are poorly known. We aimed to highlight by using Doppler Ultrasound flow differences in the cervicofacial venous network in the case of unilateral or bilateral ligation of main venous collector trunks (external jugular vein [EJV] and internal jugular vein [IJV]) METHODS: A Doppler ultrasound was performed on 10 healthy volunteers, 8 patients with previous bilateral ligation of the EJV, 8 with a unilateral ligation of the EJV, and 8 with a unilateral ligation of the EJV and IJV, after modified radical neck dissection. The diameter, the flow direction and the peak systolic velocity (PSV) of the superficial temporal vein, the facial vein (FV) and the IJV were measured. Healthy patients had a similar right and left PSV for all the veins studied, with always antegrade flows. Patients with previous ligations had some significant right/left differences and retrograde flows. A redistribution of venous blood flow on the contralateral side of the face and neck seems to take place in the case of unilateral ligation of the EJV and/or IJV. Retrograde flows are sometimes observed in the case of previous ligation of the EJV and/or IJV and might compromise the success of venous microanastomoses.

Selective Esophagogastric Devascularization in the Modified Sugiura Procedure for Patients with Cirrhotic Hemorrhagic Portal Hypertension: A Randomized Controlled Trial.

Aim Portal hypertension is a series of syndrome commonly seen with advanced cirrhosis, which seriously affects patient's quality of life and survival. This study was designed to access the efficacy and safety of selective esophagogastric devascularization in the modified Sugiura procedure for patients with cirrhotic hemorrhagic portal hypertension. Methods Sixty patients with hepatitis B cirrhotic hemorrhagic portal hypertension and meeting the inclusion criteria were selected and randomly divided by using computer into the selective modified Sugiura group (sMSP group, n = 30) and the modified Sugiura group (MSP group, n = 30). The primary endpoint measurement is the postoperative rebleeding rate. Secondary endpoint measurements included free portal venous pressure, liver Child–Pugh score, liver volume, portal vein width and blood flow velocity, survival rate, quality of life, and dysphagia as well as other complications one year postoperatively. This trial is registered with ChiCTR, number ChiCTR2000033468. Results There was no statistically significant difference in rebleeding rates within one year after surgery between patients in the sMSP and MSP groups (χ = 0.11, p=0.73). In comparison with the MSP group, the Child–Pugh score of liver function in the sMSP group significantly increased (χ = 6.4, p=0.04) and the incidence of dysphagia was significantly reduced (χ = 6.23, p=0.01) one year after surgery. There was a statistically significant difference in the quality of life between the two groups. However, there were no statistically significant differences in free portal venous pressure (MD = −3.44, 95% CI: −7.87 to 0.98, p=0.12), postoperative liver volume (3 months: MD = -258.81, 95% CI: −723.21 to 205.57, p=0.24; 1 year: MD = −320.12, 95% CI: −438.43 to 102.78, p=0.16), postoperative portal vein width (3 months: MD = −0.06, p=0.50; 1 year: MD = 0.17, p=0.21), portal vein flow velocity (3 months: MD = 1.64, p=0.21; 1 year: MD = −1.19, p=0.57), 1-year survival rate (χ = 1.01, p=0.31), and other complications between the two groups. Conclusions Selective esophagogastric devascularization in the modified Sugiura procedure may not lower the incidence of rebleeding in the short term based on our findings. However, it may significantly improve quality of life of patients with cirrhotic hemorrhagic portal hypertension, improve liver function, and reduce postoperative dysphagia.

Evaluation of midtrimester ductus venosus diameter and peak systolic velocity to predict late onset small for gestational age fetuses

Objective The ductus venosus, a small blood vessel in the fetal venous system, has extraordinary physiologic significance because it connects the umbilical vein to the inferior vena cava in the fetus circulation system and transports highly oxygenated blood from the placenta to the fetus’ heart. Hence, assessment of ductus venosus flows is helpful in evaluating fetal hemodynamics. Considering the critical function of the ductus venosus, we hypothesized that the diameter of the midtrimester ductus venosus and its peak velocity index can be related to adequate fetal growth; therefore, the aim of this study was to evaluate the role of the midtrimester umbilical venous blood flow, ductus venosus diameter, and ductus venosus peak systolic velocity to help predict uncomplicated deliveries of late onset small for gestational age (SGA) fetuses. Methods In this prospective study we analyzed the pregnancies and deliveries of 398 pregnant women who met the inclusion criteria and divided them into three groups according to fetal birth weight as follows: birth weight <3 percentile SGA group (n = 16), birth weight 3–10 percentile SGA group (n = 42), and appropriate for the gestational age (AGA) group (n = 340). The midtrimester ductus venosus diameter and peak sistolic velocity, umbilical venous blood flow, and umbilical artery pulsatility index (PI) were recorded. In the absence of congenital anomalies, the diagnosis of fetal growth restriction (FGR) is made according to Delphi consensus criteria. In the absence of abnormal Doppler findings, late FGR was defined as occurring ≥32 weeks. Results Maternal age, nulliparity, mean gestational age at ultrasound evaluation, ethnicity, body mass index, and previous cesarean delivery rates were similar among the groups. In addition, mid-trimester fetal biometric measurements and amniotic fluid volume were similar among the groups. The gestational age at delivery, prematurity, fetal birth weight, vaginal delivery rates, and rate of admission to the neonatal intensive care unit were significantly different among the groups. The mean mid-trimester umbilical vein blood flow to abdominal circumference ratio (UVBF/AC) was similar among the groups (p=.740). In the <3 group, the mean peak systolic velocity of the ductus venosus was significantly lower and the mean diameter of the ductus venosus significantly higher than those in the 3–10 and AGA groups (both p<.001). Although the values are below the 95th percentile mid-trimester umbilical artery PI was significantly higher in the <3 percentile SGA group than in the 3–10 percentile SGA and AGA groups. Conclusion Our results suggest that the diameter and peak systolic velocity of the mid-trimester ductus venosus are useful noninvasive measurements that provide prediction of late onset SGA fetuses

Reversal of blood flow in deep cerebral vein in preterm intraventricular hemorrhage: two case reports

BackgroundIntraventricular hemorrhage during the early stage is a major complication in very low birth weight infants. Elevation of venous pressure is one of the contributing factors. The internal cerebral vein receives most of the venous flow from the subependymal germinal matrix, the most common site of origin of intraventricular hemorrhage. Recently, it has been reported that pulsatile or partially interrupted internal cerebral vein waveforms might also be risk factors for intraventricular hemorrhage in extremely low birth weight infants. Here, we report two cases of partially reversed internal cerebral vein flow with intraventricular hemorrhage. There are no published reports documenting this unique flow pattern.Case presentationBetween 2013 and 2020, we had in our neonatal intensive care unit two cases of very low birth weight infants (27 and 25 weeks of gestational age) who showed a partially reversed internal cerebral vein waveform pattern, which was recognized as a new blood flow pattern. Their internal cerebral vein flow patterns were continuously flat early after birth. They showed an intraventricular hemorrhage on the unilateral side with partially interrupted internal cerebral vein flow at 31 and 41 hours after birth (27- and 25-week-old neonates, respectively). Consecutively, their internal cerebral vein flow changed to a partially reversed pattern with intraventricular hemorrhage on the contralateral side at 43 and 87 hours after birth (27- and 25-week-old neonates, respectively). Their flow patterns improved by day 7. These partially reversed patterns were equivalent to triphasic venous flow, and the reverse flow corresponded to A- and V-waves.ConclusionIn the two cases, the internal cerebral vein flow patterns were normal and flat before intraventricular hemorrhage and changed to a severe flow pattern (partially interrupted or reversed flow) at the same time as the detection of intraventricular hemorrhage. After the development of intraventricular hemorrhage, they improved. These cases indicate that a partially reversed or interrupted internal cerebral vein flow pattern may be derived from central venous pressure elevation and related to intraventricular hemorrhage in very low birth weight infants, however, it is difficult to determine when this flow pattern occurs in relation to intraventricular hemorrhage.

Physiologically-Based Pharmacokinetic Model of Morphine and Morphine-3-Glucuronide in Nonalcoholic Steatohepatitis.

Nonalcoholic steatohepatitis (NASH), the progressive form of nonalcoholic fatty liver disease, is increasing in prevalence. NASH-related alterations in hepatic protein expression (e.g., transporters) and in overall physiology may affect drug exposure by altering drug disposition and elimination. The aim of this study was to build a physiologically-based pharmacokinetic (PBPK) model to predict drug exposure in NASH by incorporating NASH-related changes in hepatic transporters. Morphine and morphine-3-glucuronide (M3G) were used as model compounds. A PBPK model of morphine with permeability-limited hepatic disposition was extended to include M3G disposition and enterohepatic recycling (EHR). The model captured the area under the plasma concentration-time curve (AUC) of morphine and M3G after intravenous morphine administration within 0.82-fold and 1.94-fold of observed values from 3 independent clinical studies for healthy adult subjects (6, 10, and 14 individuals). When NASH-related changes in multidrug resistance-associated protein 2 (MRP2) and MRP3 were incorporated into the model, the predicted M3G mean AUC in NASH was 1.34-fold higher compared to healthy subjects, which is slightly lower than the observed value (1.63-fold). Exploratory simulations on other physiological changes occurring in NASH (e.g., moderate decreases in glomerular filtration rate and portal vein blood flow) revealed that the effect of transporter changes was most prominent. Additionally, NASH-related transporter changes resulted in decreased morphine EHR, which could be important for drugs with extensive EHR. This study is an important first step to predict drug disposition in complex diseases such as NASH using PBPK modeling.

Analysis of Contact Stability and Contact Safety of a Robotic Intravascular Cardiac Catheter under Blood Flow Disturbances.

This paper studies the contact stability and contact safety of a robotic intravascular cardiac catheter under blood flow disturbances while in contact with tissue surface. A probabilistic blood flow disturbance model, where the blood flow drag forces on the catheter body are approximated using a quasi-static model, is introduced. Using this blood flow disturbance model, probabilistic contact stability and contact safety metrics, employing a sample based representation of the blood flow velocity distribution, are proposed. Finally, the contact stability and contact safety of a MRI-actuated robotic catheter are analyzed using these models in a specific example scenario under left pulmonary inferior vein (LIV) blood flow disturbances.

Associations Between Doppler Internal Jugular Vein Blood Flow and Transverse Sinus Stasis Detected by Magnetic Resonance Imaging.

This study aimed to compare the estimated internal jugular vein (IJV) volume flow with Doppler ultrasound in patients with slow flow in the transverse sinuses and normal transverse sinuses on brain magnetic resonance imaging (MRI). Eighty patients between the ages of 18 and 80 years who did not have any signs of sinus vein thrombosis on brain MRI were included. On MRI, cases with hyperintensity due to a signal void loss in the transverse sinuses in coronal fluid attenuation inversion recovery sequences were included in the slow-flow group. The presence of sinus thrombosis was excluded with other MRI pulse sequences and clinical findings. The participants were divided into 2 groups as having normal and slow flow according to MRI findings. Then bilateral IJV volume flow measurements were made by Doppler ultrasound. Bilateral volume flow was estimated by time-averaged blood flow velocities sampled in the center of the IJV, and IJV cross-sectional areas were measured. We defined the dominant IJV as the one having the higher estimated volume flow of the 2 sides. Total estimated IJV blood flow was lower (P < .001) in patients with slow flow on MRI (546 mL/min) compared to those without (768 mL/min). A similar finding was seen for the nondominant IJV. In a receiver operating characteristic analysis, the cutoff value for the total estimated IJV volume flow was determined to be 590 mL/min, and the cutoff value for nondominant estimated IJV volume flow was determined to be 202 mL/min to distinguish between the groups. Low estimated volume blood flow in the IJV is associated with MRI evidence of stasis in the ipsilateral transverse sinus.

Combination of the right heart pathology and varicose disease as a factor of development of trophic changes in the lower extremities: a case report

Varicose disease is the most prevalent vascular disorder affecting lower extremities. Chronic venous insufficiency (CVI) is common in subjects with incompetent superficial and perforator veins. Major attention in pathogenesis of CVI is paid to horizontal venous reflux, while pathological blood flow in the superficial veins may sometimes be regarded as a postural reaction. At the same time cardiac pathology may also attribute to the development of CVI. The article presents a case report describing a female patient with combination of the right heart pathology and varicose disease associated with tricuspid regurgitation leading to constant venous reflux in the lower extremity superficial veins with further development of trophic changes.

VP40.04: Does umbilical vein blood flow assessment improve the prediction of fetal macrosomia at 36 weeks of gestation?

VP40.04: Does umbilical vein blood flow assessment improve the prediction of fetal macrosomia at 36 weeks of gestation?

New forms of vascular pathology: stylocarotid, hyoid-carotid, thyroid-carotid and stylo-jugular syndromes

For the first time the possibility of ultrasound diagnostics of stylocarotid, hyoid-carotid, thyroid-carotid and stylo-jugular syndromes is shown in patients with impaired cerebral circulation.The necessity of reconstruction of bone-cartilage transitional structures with standard MR/CT angiography is justified.Abnormal structures of the styloid process such as elongation or curvature, the hyoid bone or thyroid cartilage, often in combination with ossification of the stylohyoid or stylomandibular ligaments can cause compression of the internal carotid artery with the formation of dissection, intramural hematoma, stenosis, occlusions and aneurysms. Additionally, symptoms of impaired cerebral circulation start to develop in these patients. Extravasal compression by the styloid process and/or the transverse process of the first cervical vertebra can reduce the blood flow in the internal jugular vein. But only standard vascular imaging is performed in cases of cerebral circulatory disorders, without reconstruction of adjacent bone and cartilage structures. Therefore, there is insufficient data on compression lesions of the neck vessels. Moreover, there is lack of data on ultrasound imaging of vascular Eagle syndrome. The article presents authors` experience of ultrasound diagnostics of this pathology in combination with clinical, angiographic and CT nuances.

Ophthalmic Artery and Superior Ophthalmic Vein Blood Flow Dynamics in Glaucoma Investigated by Phase Contrast Magnetic Resonance Imaging.

Ophthalmic artery (OA) and superior ophthalmic vein (SOV) blood flow were quantified by phase contrast magnetic resonance imaging (PC MRI) and seemed lower in glaucoma. Venous flow dynamics was different in glaucoma patients with a significantly decreased pulsatility. Studies using color Doppler imaging and optical coherence tomography flowmetry strongly suggested that vascular changes are involved in the pathophysiology of glaucoma, but the venous outflow has been little studied beyond the episcleral veins. This study measured the OA and the SOV flow by PC MRI in glaucoma patients compared with controls. Eleven primary open-angle glaucoma patients, with a mean±SD visual field deficit of -2.3±2.7 dB and retinal nerve fiber layer thickness of 92±13 µ, and 10 controls of similar age, were examined by PC MRI. The mean, maximal and minimal flow over cardiac cycle were measured. The variation of flow (ΔQ) was calculated. The OA mean±SD mean flow was 13.21±6.79 in patients and 15.09±7.62 mL/min in controls (P=0.35) and the OA maximal flow was 25.70±12.08 mL/min in patients, and 28.45±10.64 mL/min in controls (P=0.22). In the SOV the mean±SD mean flow was 6.46±5.50 mL/min in patients and 7.21±6.04 mL/min in controls (P=0.81) and the maximal flow was 9.06±6.67 in patients versus 11.96±9.29 mL/min in controls (P=0.47). The ΔQ in the SOV was significantly lower in patients (5.45±2.54 mL/min) than in controls (9.09±5.74 mL/min) (P=0.04). Although no significant difference was found, the mean and maximal flow in the OA and SOV seemed lower in glaucoma patients than in controls. The SOV flow waveform might be affected in glaucoma, corroborating the hypothesis of an impairment of venous outflow in those patients.

Ультразвукові параметри печінки та показники портальної гемодинаміки при коморбідності неалкогольної жирової хвороби печінки з артеріальною гіпертензією

Об’єктом дослідження були 269 пацієнтів, які входили у три групи: група І – пацієнти з коморбідністю НАЖХП та ГХ ІІ стадії, 2 ступеню (121 пацієнт), група ІІ – пацієнти з коморбідністю НАЖХП та РПАГ ІІ стадії, 2 ступеню (88 пацієнтів), група ІІІ – пацієнти з НАЖХП (60 пацієнтів). Вік пацієнтів складав від 18 до 66 років. Середній вік пацієнтів становив (48,07±10,81) року. Контрольна група – 20 здорових осіб аналогічної вікової категорії чоловічої та жіночої статі. Для оцінки стану печінки використовували ультразвуковий метод дослідження на ультразвуковій діагностичній системі „GE”, США. За нашими даними, показники кровотоку у портальній вені погіршуються як у пацієнтів з НАЖХП так і її коморбідністю з ГХ або РПАГ. Індекс резистивності загальної печінкової артерії знижується у більшій мірі у пацієнтів з НАЖХП та її коморбідністю з ГХ або РПАГ порівняно як з хворими з ізольованою НАЖХП, так і з групою контролю. Пульсаційний індекс загальної печінкової артерії достовірно не відрізняється від хворих з коморбідністю та ізольованою НАЖХП, але достовірно перевищує показник у групі контролю. Це також свідчить про наявність порушень у системі артеріального печінкового кровотоку у досліджених хворих. Різниця між показниками портальної гемодинаміки відсутня при коморбідності НАЖХП з ГХ та коморбідності НАЖХП з РПАГ. Отриманні дані свідчать про те, що наявність коморбідності з ГХ або РПАГ у пацієнтів з НАЖХП, погіршує стан портального кровотоку, що може впливати на перебіг захворювання.

The impact of umbilical vein blood flow and glucose concentration on blood flow distribution to the fetal liver and systemic organs in healthy pregnancies.

Glucose is a major energy substrate for the fetus, including liver, heart, and brain metabolism. The umbilical vein (UV) blood flow supplies the fetal liver directly from the placenta, whereas a fraction is shunted via ductus venosus (DV) to the fetal systemic circulation bypassing the fetal liver. We hypothesized UV glucose concentration to be a major regulator of the distribution of glucose supply between the fetal liver and DV, and explored the influence of maternal metabolic status on this distribution. We included 124 healthy women with normal singleton pregnancies, scheduled for elective cesarean section. UV and DV blood flow measurements were performed by Doppler ultrasound immediately before, and blood samples were obtained during surgery. UV blood flow was significantly correlated with DV blood flow, liver blood flow, and the DV shunting fraction, while UV glucose concentration was not. For normal-weight mothers, the maternal-fetal glucose gradient was positively correlated with DV shunting fraction, and negatively with liver blood flow. For the fetuses of the overweight mothers no such correlation was found. This indicates that within the normal physiological range the human fetus makes adaptations of blood flow to ensure individual needs related to the offered maternal energy supply.