Blood Flow Resistance Research Articles

Electrical Stimulation of Afferent Lumbar Sympathetic Nerve Impacts Cardio‐Respiratory Functions in Anesthetized Rats

The lumbar sympathetic chains (LSC) contain post-ganglionic vasodilator and vasoconstrictor fibers that control hindlimb vascular tone. The LSC also contain dorsal root ganglion afferent fibers whose roles in cardiorespiratory status remain poorly understood. The objective of the present study was to characterize the cardiorespiratory responses elicited by electrical stimulation (ES) of a LSC in urethane-anaesthetized male Sprague-Dawley rats (n=6) instrumented to measure/calculate mean arterial blood pressure (MAP), femoral artery blood flow (FBF) and femoral vascular resistance (FVR), brachial artery blood flow (BBF), and brachial vascular resistances (BVR), upper airway pressure (UAP), diaphragmatic EMG, respiratory frequency, inspiratory (iTV) and expiratory (eTV) tidal volumes. The right LSC was identified at the level of L4-L6 and a bipolar electrode was placed for ES (5 Hz, 0.5 msec duration, 0.5 mA amplitude for 10 sec). LSC stimulation caused a distinct pattern of cardiorespiratory responses including (a) a 12% decrease in MAP, (b) 15% decrease in ipsilateral FVR, (c) a 10% decrease in BVR (all measured at the peak decrease in MAP), (d) a 15% increase in iVT, (e) a 10% increase in eVT, (f) a15% increase in respiratory frequency, and (g) a 9% increase in diaphragmatic EMG activity. The result of this study demonstrates that ES of afferent fibers within the LSC elicits an array of cardiorespiratory changes in anesthetized rats that would be consistent with preparing the rats for exercise and for flight.

Mineralocorticoid Receptor Blockade Normalizes Coronary Resistance in Obese Swine Independent of Functional Alterations in K v Channels

Impaired coronary microvascular function (e.g., reduced dilation to physiological stimuli and decreased coronary flow reserve) predicts cardiac mortality in obesity, yet underlying mechanisms and potential therapeutic strategies remain poorly understood. Mineralocorticoid receptor (MR) antagonism improves coronary microvascular function in obese humans and animals. Whether this results from improved regulation of coronary resistance, a process dependent on voltage-dependent K+ (Kv) channel activation, or reduced coronary structural remodeling is unclear. Indeed, recent evidence suggests MR-dependent regulation of vascular K+ channels and pathologic stiffening. Thus, the goals of this investigation were to determine: 1) the effects of obesity on coronary vasodilation to graded reductions in arterial PO2; 2) the contribution of Kv channels to hypoxemic coronary vasodilation; and 3) whether chronic MR blockade improves hypoxemia-induced coronary vasodilation in obesity and underlying mechanisms. Hypoxemia increased coronary blood flow to a similar degree in lean and obese swine, however coronary vascular resistance was significantly higher in obese swine. Inhibition of Kv channels reduced coronary blood flow and augmented coronary resistance under baseline conditions in lean but not obese swine and had no impact on hypoxemic coronary vasodilation. Chronic MR inhibition in obese swine normalized baseline coronary resistance, did not influence hypoxemic coronary vasodilation, or restore coronary Kv function (assessed in vivo, ex vivo, and via patch clamping). Lastly, MR blockade prevented obesity-associated coronary arteriolar stiffening independent of cardiac capillary density. These data indicate that chronic MR inhibition prevents increased coronary resistance in obesity independent of alterations in Kv channel function.

Establishment and evaluation of a rat model of extracorporeal membrane oxygenation (ECMO) thrombosis using a 3D-printed mock-oxygenator

BackgroundExtracorporeal membrane oxygenation (ECMO) research using large animals requires a significant amount of resources, slowing down the development of new means of ECMO anticoagulation. Therefore, this study developed and evaluated a new rat ECMO model using a 3D-printed mock-oxygenator.MethodsThe circuit consisted of tubing, a 3D-printed mock-oxygenator, and a roller pump. The mock-oxygenator was designed to simulate the geometry and blood flow patterns of the fiber bundle in full-scale oxygenators but with a low (2.5 mL) priming volume. Rats were placed on arteriovenous ECMO at a 1.9 mL/min flow rate at two different heparin doses (n = 3 each): low (15 IU/kg/h for eight hours) versus high (50 IU/kg/h for one hour followed by 25 IU/kg/h for seven hours). The experiment continued for eight hours or until the mock-oxygenator failed. The mock-oxygenator was considered to have failed when its blood flow resistance reached three times its baseline resistance.ResultsDuring ECMO, rats maintained near-normal mean arterial pressure and arterial blood gases with minimal hemodilution. The mock-oxygenator thrombus weight was significantly different (p < 0.05) between the low (0.02 ± 0.006 g) and high (0.003 ± 0.001 g) heparin delivery groups, and blood flow resistance was also larger in the low anticoagulation group.ConclusionsThis model is a simple, inexpensive system for investigating new anticoagulation agents for ECMO and provides low and high levels of anticoagulation that can serve as control groups for future studies.

Changes in Umbilico-Placental Circulation during Prolonged Intact Cord Resuscitation in a Lamb Model.

Some previous studies reported a benefit to cardiopulmonary transition at birth when starting resuscitation maneuvers while the cord was still intact for a short period of time. However, the best timing for umbilical cord clamping in this condition is unknown. The aim of this study was to explore the duration of effective umbilico–placental circulation able to promote cardiorespiratory adaptation at birth during intact cord resuscitation. Umbilico–placental blood flow and vascular resistances were measured in an experimental neonatal lamb model. After a C-section delivery, the lambs were resuscitated ventilated for 1 h while the cord was intact. The maximum and mean umbilico–placental blood flow were respectively 230 ± 75 and 160 ± 12 mL·min−1 during the 1 h course of the experiment. However, umbilico–placental blood flow decreased and vascular resistance increased significantly 40 min after birth (p < 0.05). These results suggest that significant cardiorespiratory support can be provided by sustained placental circulation for at least 1 h during intact cord resuscitation.

Low‐dose aspirin treatment improves endometrial receptivity in the midluteal phase in unexplained recurrent implantation failure

AbstractObjectiveTo compare endometrial receptivity in patients with and without unexplained recurrent implantation failure (URIF) and the benefits of low‐dose aspirin treatment in women with URIF.MethodsA retrospective study was conducted at Ren Ji Hospital, Shanghai, from January 2014 to January 2017. Endometrial thickness, pulsatility index (PI), resistive index (RI), and systolic‐to‐diastolic ratio (S/D) values of endometrial and uterine perfusion were recorded and compared between women with and without URIF. Receiver operating characteristic (ROC) curve analysis was used to evaluate the predictive accuracy of the risk of URIF. Ultrasonography examination was repeated after 2 months of treatment with low‐dose aspirin.ResultsPI, RI, and S/D values for endometrial blood flow were significantly higher in URIF patients than the control group (P &lt; 0.001). The predictive indexes were 0.833, 0.857, and 0.839, respectively. Differences between the groups for endometrial thickness and impedance of uterine perfusion were not significant (P &gt; 0.05). After low‐dose aspirin treatment, endometrial and uterine arterial blood flow resistance in URIF patients was significantly lower than before treatment (P &lt; 0.05).ConclusionURIF patients had inappropriate endometrial blood flow. Doppler parameters are promising for predicting women at high risk of URIF. Low‐dose aspirin treatment can improve endometrial receptivity.

Mas Receptor Blockade Promotes Renal Vascular Response to Ang II after Partial Kidney Ischemia/Reperfusion in a Two-Kidney-One-Clip Hypertensive Rats Model.

Background Partial kidney ischemia-reperfusion (IR) injury is the principal cause of acute kidney injury. The renin-angiotensin system (RAS) and hypertension also may be influenced by renal IR injury. In two models of partial renal IR with and without ischemia preconditioning (IPC) and using Mas receptor (MasR) blockade, A779 or its vehicle, the renal vascular responses to angiotensin II (Ang II) administration in two-kidney-one-clip (2K1C) hypertensive rats were determined. Methods Thirty-seven 2K1C male Wistar rats with systolic blood pressure ≥150 mmHg were randomly divided into three groups; sham, IR, and IPC + IR. The animals in the sham group underwent surgical procedures except partial IR. The rats in the IR group underwent 45 min partial kidney ischemia, and the animals in the IPC + IR group underwent two 5 min cycles of partial kidney ischemia followed by 10 min reperfusion and partial kidney ischemia for 45 min. The renal vascular responses to graded Ang II (30, 100, 300, and 1000 ng kg−1.min−1) infusion using A779 or its vehicle were measured at constant renal perfusion pressure. Results Four weeks after 2K1C implementation, the intravenous infusion of graded Ang II resulted in dose-related increases in mean arterial pressure (MAP) (Pdose < 0.0001) that was not different significantly between the groups. No significant differences were detected between the groups in renal blood flow (RBF) or renal vascular resistance (RVR) responses to Ang II infusion when MasR was not blocked. However, by MasR blockade, these responses were increased in IR and IPC + IR groups that were significantly different from the sham group (P < 0.05). For example, infusion of Ang II at dose 1000 ng kg−1.min−1 resulted in decreased RBF percentage change (RBF%) from the baseline to 17.5 ± 1.9%, 39.7 ± 3.8%, and 31.0 ± 3.4% in sham, IR, and IPC + IR, respectively. Conclusion These data revealed the important role of MasR after partial kidney IR in the responses of RBF and RVR to Ang II administration in 2K1C hypertensive rats.

Combination of polycarboxybetaine coating and factor XII inhibitor reduces clot formation while preserving normal tissue coagulation during extracorporeal life support

Blood contact with high surface area medical devices, such as dialysis and extracorporeal life support (ECLS), induces rapid surface coagulation. Systemic anticoagulation, such as heparin, is thus necessary to slow clot formation, but some patients suffer from bleeding complications. Both problems might be reduced by 1) replacing heparin anticoagulation with artificial surface inhibition of the protein adsorption that initiates coagulation and 2) selective inhibition of the intrinsic branch of the coagulation cascade. This approach was evaluated by comparing clot formation and bleeding times during short-term ECLS using zwitterionic polycarboxybetaine (PCB) surface coatings combined with either a potent, selective, bicyclic peptide inhibitor of activated Factor XII (FXII900) or standard heparin anticoagulation. Rabbits underwent venovenous ECLS with small sham oxygenators for 60 min using three means of anticoagulation (n = 4 ea): (1) PCB coating + FXII900 infusion, (2) PCB coating + heparin infusion with an activated clotting time of 220–300s, and (3) heparin infusion alone. Sham oxygenator blood clot weights in the PCB + FXII900 and PCB + heparin groups were 4% and 25% of that in the heparin group (p < 10−6 and p < 10−5), respectively. At the same time, the bleeding time remained normal in the PCB + FXII900 group (2.4 ± 0.2 min) but increased to 4.8 ± 0.5 and 5.1 ± 0.7 min in the PCB + heparin and heparin alone groups (p < 10−4 and 0.01). Sham oxygenator blood flow resistance was significantly lower in the PCB + FXII900 and PCB + heparin groups than in the heparin only group (p < 10−6 and 10−5). These results were confirmed by gross and scanning electron microscopy (SEM) images and fibrinopeptide A (FPA) concentrations. Thus, the combined use of PCB coating and FXII900 markedly reduced sham oxygenator coagulation and tissue bleeding times versus the clinical standard of heparin anticoagulation and is a promising anticoagulation method for clinical ECLS.

The Effect of Trans-Abdominal Chorionic Villus Sampling on Fetal Heart Rate and Placental Vascular Resistance Index: A Color Doppler Ultrasound Study

Fetal hemodynamic changes can occur immediately following invasive chorionic villus sampling (CVS). We decided to study the possible effect of CVS on fetal heart rate (FHR), and uteroplacental resistance index (RI) changes using color Doppler ultrasound. Thirty-five pregnant patients with a gestational age of more than 12 weeks were included. Trans-abdominal CVS was done to assess the possibility of thalassemia. Before and after the CVS, color Doppler ultrasound was done to measure FHR and uteroplacental RI. Mean (SD) values for FHR before and after the CVS were 175.22 (±9) and 173.62 (±9.94) beats per minute, respectively; P=0.18. Mean (SD) uteroplacental RI before the CVS was 0.79 (0.07) which significantly increased to 0.82 (0.08); P=0.03. We observed a significant increase in resistance of blood flow in placental circulation after CVS. However, no significant change was observed regarding FHR after CVS.

Analysis of Clinical Diagnostic Value of High Frequency Colour Doppler Ultrasound for Abdominal Wall Endometriosis

Abdominal wall endometriosis is a common endometriosis, which is located outside the endometrium, such as the myometrium or subcutaneous fat layer of the abdominal wall, forming a mass, active and infiltrating into the surrounding tissue, accompanied by menstrual pain, and seriously affecting the quality of life of patients. With the increasing operation of caesarean section and other traumatic operations, the incidence rate of abdominal wall endometriosis is increasing. Because of the variety of clinical manifestations of abdominal wall endometriosis, there are many kinds of diagnostic methods. Choosing the appropriate diagnostic methods to confirm abdominal wall endometriosis has become the primary work of diagnosis and treatment of abdominal wall endometriosis. This paper discusses the clinical value of high frequency colour doppler ultrasound in the diagnosis of abdominal wall endometriosis. Compared with the diagnosis of ordinary ultrasound and high frequency colour doppler ultrasound, the location, shape, size, boundary, internal echo, blood flow velocity, blood flow resistance and other parameters of the mass in the focus were observed. It is proved that the application of high-frequency colour doppler ultrasound can greatly improve the ultrasonic diagnosis rate of abdominal wall endometriosis, and it is non-invasive, radiation-free, low price, easy for patients to accept. It provides a high value clinical diagnosis basis for the early detection and treatment of abdominal wall endometriosis.

Brain capillary pericytes exert a substantial but slow influence on blood flow.

The majority of the brain’s vasculature is comprised of intricate capillary networks lined by capillary pericytes. However, it remains unclear whether capillary pericytes influence blood flow. Using two-photon microscopy to observe and manipulate brain capillary pericytes in vivo, we find that their optogenetic stimulation decreases lumen diameter and blood flow, but with slower kinetics than similar stimulation of mural cells on upstream pial and pre-capillary arterioles. This slow vasoconstriction was inhibited by the clinically-used vasodilator fasudil, a Rho-kinase inhibitor that blocks contractile machinery. Capillary pericytes were also slower to constrict back to baseline following hypercapnia-induced dilation, and slower to dilate towards baseline following optogenetically-induced vasoconstriction. Optical ablation of single capillary pericytes led to sustained local dilation and a doubling of blood cell flux selectively in capillaries lacking pericyte contact. These data indicate that capillary pericytes contribute to basal blood flow resistance and slow modulation of blood flow throughout the brain.

Role of uterine artery Doppler in assessment of unexplained infertility

BackgroundThe study aimed to compare the values of uterine artery Doppler indices including resistance index (RI), pulsatility index (PI), and systolic/diastolic (S/D) ratios in fertile female and female with unexplained infertility and investigate their association with unexplained infertility. This study included 70 women divided into two groups. Study group included 40 women with unexplained infertility and control group included 30 fertile women.ResultsThe mean ages of study and control groups were 26.9 and 28.5 years respectively. In infertile group, the mean values of uterine arteries resistance index (RI), pulsatility index (PI), and systolic/diastolic (S/D) ratios were 0.9, 2.9, and 8.0 respectively. In the fertile control group, mean RI and PI values and S/D ratio were 0.6, 1.5, and 2.7 respectively. There was statistically significant difference as regards RI, PI, and S/D ratios between study and control groups. The best cut off values of RI, PI, and S/D ratios for predicting increased uterine blood flow impedance were more than 0.67, 1.95, and 3 respectively with sensitivity of 100%, 95%, and 100% respectively, specificity of 96.7%, 86.7%, and 96.7% respectively, and diagnostic accuracy of 98.6%, 91.42%, and 98.57% respectively.ConclusionUterine artery Doppler indices mean values were higher in unexplained infertility women than fertile women. Uterine artery Doppler indices have high sensitivity and specificity for diagnosis of high uterine blood flow impedance. High uterine blood flow impedance diagnosed by uterine artery Doppler may contribute in the etiology of unexplained infertility. Uterine artery Doppler should be included in investigation of unexplained infertility.

Intrauterine infusion of killed semen adversely affects uterine blood flow and endometrial gene expression of inflammatory cytokines in mares susceptible to persistent breeding-induced endometritis

Persistent breeding-induced endometritis (PBIE) is a leading cause of infertility in mares. The objective of the study was to assess genital perfusion and endometrial gene expression of inflammatory cytokines in mares classified as susceptible (n = 5) or resistant (n = 5) to PBIE. Ten mares were examined daily during estrus until 6 d after hCG-induced ovulation for two estrous cycles. Twenty-four hours after application of 1500 IU hCG, 4 mL of killed (by repeated freezing in liquid nitrogen and thawing at 50 °C) deep-frozen semen or sterile saline was instilled into the uterine body and examinations were carried out immediately before and 3, 6, and 12 h after intrauterine infusion. Examinations included blood sampling to determine plasma progesterone (P4) concentrations, and transrectal ultrasonography in B- and color Doppler mode to determine follicular and luteal size and blood flow, the extent of intrauterine fluid, as well as time-averaged maximum velocity (TAMV), blood flow volume (BFV), and blood flow resistance (expressed as pulsatility index, PI) of the uterine arteries. Additionally, endometrial biopsies were obtained at 24 h before, and 2 and 7 d after infusion, and mRNA expressions of IL1B, IL6, IL8, IL10, TNF, CASP3, and COX2 were determined by qRT-PCR. Statistical analyses were performed with mixed models. Intrauterine fluid retention (diameter >20 mm for at least 3 d) was found after infusion of killed semen in five susceptible mares. There was no treatment effect (semen vs saline; P > 0.05) on genital blood flow, plasma P4 concentration, and endometrial gene expression. In comparison to resistant mares, susceptible mares had an increased (P = 0.04) BFV of the uterine arteries at 24 h before intrauterine infusion of killed semen, and an increased (P = 0.03) PI at 2 d after infusion. The TAMV, plasma P4 concentrations, and follicular and luteal size and blood flow did not differ (P > 0.05) between resistant and susceptible mares. Endometrial mRNA expression of IL1B increased (P = 0.05) at 2 d after the infusion of killed semen in the susceptible mares, and the expression of IL10 increased (P = 0.003) at 7 d after the infusion within the resistant mares. Interleukin 6 mRNA was increased (P = 0.05) in susceptible compared to resistant mares at 2 d after infusion. In summary, an intrauterine infusion of killed semen increases uterine blood flow resistance and alters endometrial gene expression of inflammatory cytokines for at least 7 d but does not affect ovarian blood supply and luteal function in mares susceptible to PBIE.

On the poro-elastic models for microvascular blood flow resistance: An in vitro validation

Nowadays, adequate and accurate representation of the microvascular flow resistance constitutes one of the major challenges in computational haemodynamic studies. In this work, a theoretical, porous media framework, ultimately designed for representing downstream resistance, is presented and compared against an in vitro experimental results. The resistor consists of a poro-elastic tube, with either a constant or variable porosity profile in space. The underlying physics, characterizing the fluid flow through the porous media, is analysed by considering flow variables at different network locations. Backward reflections, originated in the reservoir of the in vitro model, are accounted for through a reflection coefficient imposed as an outflow network condition. The simulation results are in good agreement with the measurements for both the homogenous and heterogeneous porosity conditions. In addition, the comparison allows identification of the range of values representing experimental reservoir reflection coefficients. The pressure drops across the heterogeneous porous media increases with respect to the simpler configuration, whilst flow remains almost unchanged. The effect of some fluid network features, such as tube Young’s modulus and fluid viscosity, on the theoretical results is also elucidated, providing a reference for the invitro and insilico simulation of different microvascular conditions.

Relationship between temporal changes of endometrial blood flow impedance during natural and hormone replacement cycles and prediction of pregnancy during vitrified-warmed embryo transfer.

This study aimed to examine the relationship between the temporal changes in endometrial blood flow impedance during natural and hormone replacement therapy (HRT) cycles and clinical outcomes of vitrified-warmed embryo transfer (ET). This retrospective observational cohort study included 60 women, 28 with natural, and 32 with HRT cycles, who underwent vitrified-warmed ET. Uterine radial artery resistance index (RA-RI) was measured during the natural and HRT cycles at the following time points: early follicular phase, day of the human chorionic gonadotropin injection during a natural cycle or day of progesterone administration during an HRT cycle, and day of ET. The clinical pregnancy rates of the natural and HRT cycles were 32.1% and 34.4%, respectively. The RA-RI at the early follicular phase was significantly lower in the pregnant group than in the nonpregnant group with natural but not HRT cycles (p = 0.04). The odds ratio for pregnancy was 0.70 (95% confidence interval [CI], 0.52-0.95) when the RA-RI value at the early follicular phase was increased by 0.01 in the natural cycle. With the natural cycle, the area under the receiver-operating characteristic curves for the RA-RI at the early follicular phase with a threshold of 0.68 was 0.75 (95% CI, 0.57-0.93), and the positive and negative predictive values were 0.53 (95% CI, 0.37-0.59) and 0.92 (0.74-0.99), respectively. RA-RI at the early follicular phase might be an effective and useful tool for deciding between natural or HRT cycles for vitrified-warmed ET.

Considering evidence in the management of fetal growth restriction.

Considering evidence in the management of fetal growth restriction.

The Impact of Khat (Catha edulis) on Hemodynamics of the Common Carotid Arteries in Regular Khat Chewers: A Case-control Study Using Doppler Ultrasound.

Background:To evaluate the effect of chewing khat on the hemodynamics of the common carotid arteries (CCAs) using Doppler ultrasound imaging.Methods:This is a cross-sectional case–control study. Fifty volunteers who were chronic regular khat chewers were selected and compared with healthy nonkhat chewers. They were examined using Doppler imaging with a 7–10 MHz linear transducer. The resistivity index (RI), pulsatility index (PI), peak systolic velocity (PSV), and end-diastolic velocity of the CCAs were determined according to the standard protocol of carotid Doppler ultrasound.Results:The RI and PI of the right and left CCAs were significantly higher in khat chewers compared to controls (P < 0.001). The PSV of the right and left CCAs was considerably higher in khat chewers compared to controls (P < 0.001 and 0.04, respectively).Conclusion:The Doppler values of blood flow velocity, resistivity, and pulsatility were significantly higher in chronic regular khat chewers compared to nonkhat chewers. Khat is a significant contributory factor for increasing the hemodynamics of the CCAs.

Optimal parameters of blood flow restriction and resistance training on quadriceps strength and cross-sectional area and pain in knee osteoarthritis

BACKGROUND: Knee osteoarthritis (KOA) is one of the most common chronic diseases impacting millions of elderly people. OBJECTIVES: The study compared the effects of two intensities of partial blood flow restriction (BFR) with low-intensity resistance training on quadriceps strength and cross-sectional area (CSA), and pain in people with knee osteoarthritis (PwKOA). METHODS: Thirty-five PwKOA, aged 50–65, participated. Quadriceps CSA was measured by ultrasonography, quadriceps strength – by isokinetic dynamometry and pain by VAS. These outcome variables were obtained at the beginning of the study and re-evaluated eight weeks after the intervention. RESULTS: An interaction effect was present for quadriceps CSA (P= 0.042) and quadriceps strength (P= 0.006), showing that using 70% of total occlusion pressure with 30% 1RM had a more significant effect. Knee pain improved significantly through the main effect of BFR (P&lt; 0.001), and low-intensity resistance training (P= 0.011). Pain improved more at 70% of total occlusion pressure, with 30% of 1RM (2.5 ± 1.06) than 50% total occlusion pressure with 10% of 1RM (5.77 ± 1.46). CONCLUSION: A combination of 70% of total occlusion pressure with 30% 1RM could be beneficial in PwKOA in improving pain, and increasing the quadriceps strength. The changes in the quadriceps strength could be a predictor for knee pain.

Effect of Progesterone Replacement Therapy on Uteroplacental Circulation in Treatment of Threatened Abortion

Background: Miscarriage is interruption or termination of pregnancy before 20 weeks based upon the day of the last normal menses or it is the expulsion of the product of conception before the age of medicolegal viability which is 26th weeks of gestation in Egypt or fetal weight < 500gm or fetal length ≤ 25 according to WHO definition. Objective: This study was performed to compare the effect of vaginal micronized progesterone and oral dydrogesterone on utero-placental circulation in threatened miscarriage. Patients and Methods: A prospective clinical study in Zagazig University Hospital during the period from December 2018 to August 2019. Included fifty pregnant cases complaint of first trimester vaginal bleeding and diagnosed as threatened miscarriage. They were classified into two groups on a randomized basis, the first group received micronized vaginal progesterone (400 microgram daily) while the second one received dydrogesterone orally (40 mg at once then 10 mg every 8 hours). Both groups were followed up every two weeks for three visits by serial transvaginal Doppler ultrasound measurement of pulsatility index, resistance index, and systolic/diastolic (S/D) ratio of the spiral arteries, uterine arteries & intrachorionic area. Results: The study demonstrated that vaginal progesterone administration, contrary to oral dydrogesterone treatment, decreased spiral artery pulsatility and resistive indices. No major changes in the uterine artery blood flow impedance were observed, only S/D ratio significantly decreased in the dydrogesterone group. Conclusion: It could be concluded that vaginally administrated progesterone was nearly as equally effective as oral dydrogesterone in prevention of miscarriage in pregnant women with threatened abortion with different effects on the uteroplacental circulation.

Pathogenesis and clinical significance of the hyperdynamic circulatory syndrome in liver cirrhosis. Review

Portal hypertension is the major consequences of liver cirrhosis and is accompanied by pathologic increase in portal blood flow resistance. As portal hypertension develops that results in formation of vessel’s collaterals and arterial vasodilatation. Hyperdynamic alternations become more significant due to hyporesponsiveness to vasoconstrictors and increased shunts formation with autonomic neuropathy. This combination of liver failure and portal hypertension leads to the hyperdynamic circulatory state partly owing to simultaneous vasodilatation of splanchnic and peripheral arterial vessels. So hyperdynamic circulatory syndrome is a late complication of portal hypertension due to liver cirrhosis. The main features of hyperdynamic circulatory syndrome are high cardiac output, increased heart rate and total blood volume coupled with decreased total systemic vascular resistance. Some of these cardiovascular changes are reversible after liver transplantation what show pathophysiological significance of portal hypertension. In this paper, we aimed to review pathophysiology and features of hyperdynamic syndrome that are well-known and directly related to portal hypertension (varices, ascites, hepatic encephalopathy and hepatorenal syndrome), while others are more rare and therefore further investigations are necessary (portopulmonary hypertension, cirrhotic cardiomyopathy).

Ультразвукова діагностика стану рубця на матці у вагітних та невагітних жінок

The dynamic increase in the number of caesarean section in Ukraine and around the world remains one of the main topics of discussion, which is intensively discussing by leading scientists. The traditional assessment of the ability of the uterus scar during pregnancy, based mainly on the analysis of clinical and anamnestic data, is not high informative, and the ambiguous conclusions of the sonographic study indicate the need for further detailed study. Therefore, there is reason to believe that the development of criteria for ultrasound assessment of the condition of the uterus scar after previous cesarean section will use them to predict the possibility of spontaneous delivery in the future and remains relevant. The objective: study the features of ultrasound diagnosis of the condition of the scar on the uterus in pregnant and non-pregnant women. Materials and methods. Observations and retrospective analysis of medical records of pregnant women and birth histories in 150 women with a scar on the uterus after a previous cesarean section for the period from 2014–2019. Results. In women who became pregnant up to a year after the previous cesarean section, the most pronounced changes in blood flow were in the uterine arteries, especially during gestation 28–34 weeks. Also, in women with a failed uterus scar, changes in blood flow were most often observed in the uterine arteries at all levels and were significantly higher, compared with women with a capable uterus scar and women from the control group. In women with an insolvent uterus scar, the most pronounced changes in the indices of vascular resistance was observed in the uterine arteries, in particular the right uterine artery. Conclusion. The peculiarities of blood flow and vascular resistance in different vessels of the myometrium depending on the gestation period and the timing of pregnancy after a previous cesarean section. The obtained detailed ultrasound examination and mathematical calculation of the results of ultrasound examination of the uterus and postoperative uterus scar after previous cesarean section in non-pregnant women allowed to create a scale for assessing the condition of the uterus scar after previous cesarean section in non-pregnant women. Keywords: cesarean section, uterus scar, ultrasound, pre-pregnancy preparation of women.