Maximal Blood Flow Research Articles

Blood flow in the umbilical vein of the fetus in first half of pregnancy

The present investigation aims at studying the blood flow in the umbilical vein in the first half of normal pregnancy. It was shown that the establishing of hemocirculation passes through 4 periods: 8- 10th, 11-12th, 13-16th and after the 16th week of pregnancy. Besides that, statistically verified changes in maximum blood flow speed and index of pulsation in this vessel were revealed. Constant bloodstream spectrum reflects stability of oxygenic bloodsupply of the fetus.

Гемодинамические показатели в центральной артерии сетчатки при активной ретинопатии недоношенных и их соотношение с центральной веной сетчатки

Purpose. To analyze the main hemodynamic parameters in the central retinal artery, as well as their relationship with hemodynamic indicators in the central retinal vein, depending on the stage and type of active ROP with the use of color duplex scanning. Material and methods. The 63 premature babies with various stages of active ROP and no signs of ROP were included in the study. The 55 children with active ROP included in the study were distributed according to the stages and type of disease course. All children were at the same gestational age at the time of examination – 37–38 weeks of postmenstrual age or at 6–11 weeks of life. For all these children were performed color duplex scanning of the vessels of the eye and orbit in the modes of color Doppler mapping and pulsed Doppler. Results. The study of the hemodynamic features of the central retinal artery in premature infants with active ROP showed that the progression of the disease was accompanied by a significant increase in blood flow velocity (Vsyst and Vdiast) with each subsequent stage of ROP. A higher index of peripheral vascular resistance is recorded in comparison with the non-progressive favorable type for children with an unfavorable course of the disease.The analysis of the ratio of the maximum blood flow velocities in the central retinal artery and central retinal vein made it possible to determine in which of the vessels the hemodynamic changes are most pronounced, depending on the stage and form of active ROP. Conclusion. Thus, there are statistically significant changes in such large vessels of the retinal bed as the central retinal artery and central retinal vein during active ROP. Color duplex scanning, having a significant diagnostic potential in assessing hemodynamic parameters, made it possible to obtain reliable information about the linear blood flow velocity and the state of peripheral resistance in the central retinal artery and their relationship with the central retinal vein. This information opens up prospects for improving the accuracy of predicting the nature of the course of the disease, especially i n the early stages. Keywords: color duplex scanning, active retinopathy of prematurity, hemodynamic parameters, central retinal artery, central retinal vein

Peripheral microvascular dysfunction is also present in patients with ischemia and no obstructive coronary artery disease (INOCA).

In patients with ischemia and no obstructive coronary artery disease (INOCA), coronary microvascular dysfunction is associated with higher rate of major adverse cardiovascular events. To demonstrate if microvascular dysfunction present in coronary microcirculation of patients with INOCA may be detected noninvasively in their peripheral circulation. 25 patients with INOCA and 25 apparently healthy individuals (controls) were subjected to nailfold videocapillaroscopy (NVC) and venous occlusion plethysmography (VOP) to evaluate peripheral microvascular function and blood collection for biomarkers analysis, including soluble vascular cell adhesion molecule-1 (sVCAM-1), endothelin-1 (ET-1) and C-reactive protein (CRP). Red blood cell velocity (RBCV) before and after ischemia (RBCVmax) were significantly lower in patients with INOCA (p = 0.0001). Time to reach maximal red blood cell velocity (TRBCVmax) was significantly longer in INOCA group (p = 0.0004). Concerning VOP, maximal blood flow (p = 0.004) and its relative increment were significantly lower in patients with INOCA (p = 0.0004). RBCVmax showed significant correlations with sVCAM-1 (r = -0.38, p < 0.05), ET-1 (r = -0.73, p < 0.05) and CRP (r = -0.33, p < 0.05). Relative increment of maximal post-ischemic blood flow was significantly correlated with sVCAM-1 (r = -0.42, p < 0.05) and ET-1 (r = -0.48, p < 0.05). The impairment of microvascular function present in coronary microcirculation of patients with INOCA can be also detected in peripheral microcirculation.

Results of ultrasound dopplerography of the penis in patients with before and after transurethral enucleation of benign prostatic hyperplasia

BACKGROUND: The development of modern technologies for the surgical treatment of urological diseases poses new questions for urologists. One of them is to evaluate the effect of transurethral enucleation of benign prostatic hyperplasia on the erectile function of patients.&#x0D; AIM: The aim of the study was to assess the state of erectile function in patients before and after transurethral enucleation of benign prostatic hyperplasia using Doppler ultrasound of the vessels of the penis.&#x0D; MATERIALS AND METHODS: The study included 102 patients with benign prostatic hyperplasia aged 50 to 80 years (average 65 years) with complaints of erectile dysfunction and urinary disorders. All patients underwent transurethral enucleation of benign prostatic hyperplasia: 55 patients with the laser method (HoLEP, group 1) and 47 patients with the bipolar method (TUEB, group 2). The severity of ED was assessed using the IIEF-5 questionnaire (International Index of Erectile Function). To assess the state of blood flow in the penis, ultrasound dopplerography of the vessels of the penis was performed using a vasoactive erection stimulator. The studies were carried out before surgery and 24 weeks after it.&#x0D; RESULTS: The results of ultrasound dopplerography of the vessels of the penis before surgery revealed the arteriogenic type of ED in 18 (17.6%) patients, the venous type in 45 (44.2%) patients, the mixed arteriovenogenic type in 22 (21.6%) patients. In 17 (16.7%) patients ED was regarded as psychogenic. 24 weeks after the operation in patients of both the 1st and 2nd groups, according to the data of the IIEF-5 questionnaire, positive dynamics of the severity of erectile function was noted, regardless of the type of ED. For patients with vasculogenic types of ED, similar trends were noted regardless of the type of surgery. Thus, in patients with arteriogenic and arteriovenogenic ED a significant increase in the maximum systolic blood flow velocity (Vmax) in the cavernous arteries was recorded, while the values of the resistance index (RI) did not change significantly. At the same time, the Vmax values in these patients were initially low before the operation, and after the operation did not reach the reference values. In patients with venogenic ED, there was no significant improvement in penile blood flow, as evidenced by the absence of significant differences in Vmax and RI values. At the same time, the RI in these patients before the operation was reduced, and the Vmax values were in the range of normal values.&#x0D; CONCLUSIONS: The erectile function of patients after transurethral enucleation of benign prostatic hyperplasia improves regardless of the type of operation and the type of erectile dysfunction. Ultrasound dopplerography of the vessels of the penis is a minimally invasive and highly informative diagnostic method that makes it possible to detect circulatory disorders in the penis and assess its state in dynamics during treatment.

Kidney Replacement Therapy for Patients Requiring Cardiopulmonary Bypass Support during Cardiac Surgery.

Kidney Replacement Therapy for Patients Requiring Cardiopulmonary Bypass Support during Cardiac Surgery.

Ultrasonography in the diagnosis of complications in patients with portal hypertension.

This review focuses on ultrasonography (US) to diagnose patients with complications in portal hypertension. Clinicians first use US to evaluate patients with suspected portal hypertension, because US is quick, simple, and radiation free. US is necessary for grading and performing paracentesis for ascites. Doppler US-based detection of reverse splanchnic vein flow or the presence of a spontaneous portosystemic shunt is highly specific in patients with cirrhosis. Since it is important to estimate spleen size in patients with portal hypertension, spleen size is usually measured by US. Spleen volume can be more accurately measured with 3D-US. Estimation of viable residual splenic volume after partial splenic embolization should be limited to cases with total splenic volume less than 1000ml. Portal vein thrombosis is often detected during the US examination performed when symptoms first appear or during the follow-up. Two-dimensional transthoracic echocardiography is an excellent noninvasive screening test in patients with pulmonary portal hypertension who can undergo it. By measuring the maximum and minimum diastolic blood flow velocities in the renal arteries using renal color Doppler US, the pulsatility index (PI) and resistive index (RI) can be calculated. The PI and RI in cirrhotic patients were significantly higher than those in healthy subjects and patients with chronic hepatitis, and showed a significant positive correlation with the Child-Pugh Score. In conclusion, US is an essential tool for the diagnosis and treatment of patients with portal hypertension.

Evaluation of Factors Affecting Wrist Radio-Cephalic Arteriovenous Fistula Maturation: A Single Institutional Observational Study

Background: Chronic renal failure is the most common indication for which arterio-venous (AV) fistula creation surgery is being performed. Various studies have found that native arteriovenous fistulas are the best in long-term patency with lower complications. We conducted this study to find out the role of preprocedural duplex ultrasound (DUS) in predicting outcomes of radio-cephalic fistula in the wrist in the North-Karnataka population. Methods: This prospective study was conducted from May 2019 to July 2020 on 50 patients who were hemodialysis-dependent and underwent AV fistula creation with age from 20 to 70 years. All the patients underwent preoperative DUS and were followed up post-operatively after one, two, and six weeks. Hemodialysis was initiated through the constructed fistula once it was mature, and the maximum blood flow through the fistula was measured. SPSS version 20.0 was used for statistical analysis. Results: Among 50 subjects, the overall cumulative success of AVF maturation was 86% (43), and failure to mature rate was 14% (7). Logistic regression of maturation outcome in the wrist autologous arteriovenous fistula for individual factors showed statistically significant results (P &lt; 0.05) for the diameter of the radial artery &gt; 1.6 mm and the distensibility of the cephalic vein &gt; 0.4 mm. Conclusions: Vein distensibility and radial artery diameter are key factors in predicting successful AVF maturation. The use of intraoperative papaverine instillation directly on vessels can improve arteriovenous fistula outcomes.

Показатели тестостерона в сыворотке крови и гемодинамики тестикул до и после инфицирования SARS-COV-2 (пилотное исследование)

INTRODUCTION: The current epidemiological situation dictates a detailed study of the effect of a new coronavirus infection (SARS-CoV-2) on various anatomical, histological, physiological and biochemical parameters of the human body, which has become an integral part of many medical research, including urology, andrology, endocrinology. OBJECTIVE: To study serum testosterone levels and testicular hemodynamics before and after infection with SARS-CoV-2. MATERIALS AND METHODS: 20 patients were examined, before and after suffering SARS-CoV-2 infection (who fell ill at the beginning of 2020). Average age 37.8 years (min=27, max=50). The level of total testosterone (s) in the blood serum and hemodynamic parameters of the testicles (maximum and minimum blood flow velocity and resistance index) were studied. RESULTS: When studying the level of s 3 months after the transferred SARS-CoV-2, its decrease from the initial value was noted (r=0.47;p=0.35), and after 6 months (r=0.98;p<0.007) there was no recovery of the target level of Ts before infection with SARS-CoV-2. Regarding the hemodynamics of the testicles, there was also a decrease in Vmax and Vmin, and an increase in RI, which indicates a deterioration in the blood flow of the testicles (p<0.001). CONCLUSION: SARS-CoV-2 affects the level of Ts in the blood serum and the parameters of the hemodynamics of the testicles. The extent to which SARS-CoV-2 affects patient performance depends largely on the severity of the disease and to a lesser extent on baseline performance.

Predicting the expression level of Ki-67 in breast cancer using multi-modal ultrasound parameters

ObjectiveThis study investigated the feasibility of predicting the expression levels of Ki-67 in breast cancer using ultrasonographic findings and clinical features.MethodsFifty-eight breast cancer patients, with 82 lesions confirmed by surgical pathology, were selected retrospectively for this study. Conventional ultrasound examination and elastography examination were performed before surgery. Clinical features (age, estrogen receptor (ER), progesterone receptor, and human epidermal growth factor receptor-2 expression levels), ultrasonographic findings, and elastography scores, including the maximum size, location, number, margin, borderline, blood flow, and elastography score of the mass, were collected. The expression of Ki-67 was recorded using immunohistochemical staining, and the patients were divided into a high (≥ 20%) expression group and a low (< 20%) expression group. SPSS 23.0 software was used for statistical analysis. An independent sample t-test was used for measurement data, and a χ2 test was used for enumeration data. Logistic regression analysis was performed for meaningful indicators, and the receiver operating characteristic curve was used to calculate the best diagnostic cut-off point.ResultsMonofactorial analysis showed that there was a statistically significant difference (p < 0.05) between the high expression of Ki-67 and the maximum diameter of the mass, the margin of the mass, the color Doppler flow imaging of the blood flow, and the resistance index of the blood flow. There were no significant differences in age, mass location, number, morphology, borderline, microcalcification, and elastography score (p > 0.05). Multiple factor regression analysis showed that a large mass and a mass with a rich blood flow had an independent predictive value for Ki-67. When the diameter was > 21.5 mm, the diagnostic sensitivity and specificity were 91.9% and 71.3%, respectively. The expression level of Ki-67 was negatively correlated with that of ER.ConclusionThe tumor size and blood flow of breast cancer is correlated with the expression level of Ki-67 and, thus, it could be used to predict the expression level of Ki-67 in ultrasound diagnosis. The margin condition and the expression level of ER of an ultrasonic mass could also indirectly reflect the Ki-67 expression level of the mass.

Developmental changes in bicuspid aortic valve and associated aortopathy in small children

Abstract Background The prevalence of bicuspid aortic valve (BAV) in newborns is 0.8%. BAV is associated with an increased risk of aortic valve dysfunction and aortopathy. Aortopathy with increased aortic diameters has recently been reported in newborns with BAV. As most patients with BAV are diagnosed in adulthood the development of BAV and associated aortopathy during early years of life is not well described. Purpose The purpose of the study was to assess changes in aortic valve function and aortic dimensions at two to four years of age in children diagnosed with BAV neonatally. Methods Children with BAV were included from a population-based cohort study, in which newborns (n≈25,000) underwent standardized transthoracic echocardiography (TTE). Follow-up TTE was performed and analyzed according to established guidelines. Neonatal (baseline) and follow-up data were compared. Diameters were indexed to body surface area (BSA). Z-scores were calculated using formulas from the Pediatric Heart Network Echocardiogram Database. Results At follow-up 101 newborns with BAV (mean age 2 years 5 months, SD 11 months), 75% male) were examined from May 2019 to April 2021. From baseline to follow-up there was an increase in the BSA-adjusted diameter of the aortic valve annulus (z-score −0.19 at baseline vs 0.95 at follow up, p&amp;lt;0.001), and of the sino-tubular junction (z-score 0.16 at baseline vs 0.43 at follow up, p&amp;lt;0.05). Conversely, there was a decrease in the Z-score for the diameter measured 1 cm from the valve annulus (z-score 1.31 at baseline vs 0.68 at follow up, p&amp;lt;0.001) and at the widest point of the visualized ascending aorta (z-score 2.44 at baseline vs 1.45 at follow up, p&amp;lt;0.001). There was no significant change in the diameter of the sinus of Valsalva (z-score 0.83 at baseline vs 0.80 at follow up, p=0.92). The number of children with at least one aortic z-score &amp;gt;3 was 31 (30.6%) at baseline and 17 (17.8%) at follow up. At baseline mild aortic valve regurgitation was observed in 18 children (17.8%) and in 23 children at follow up (23%). Mean maximum systolic velocities across the aortic valve were 1.03 m/s at baseline (SD 0.24) and 1.11 m/s at follow up (SD 0.27), p&amp;lt;0.05. Aortic stenosis, defined as flow velocity &amp;gt;2.5 m/s was seen in one child both at baseline and at follow-up. Conclusion In children diagnosed with BAV neonatally, re-examination at the age of 2.5 years showed significant increases in the diameter of the aortic valve annulus and the sino-tubular junction, but a significant decrease in the diameter of the ascending aorta. The maximum blood flow velocity across the aortic valve increased and more children had developed mild aortic valve regurgitation. Thus, the bicuspid aortic valve and the associated aortopathy seem to undergo remodeling during early childhood. Funding Acknowledgement Type of funding sources: Foundation. Main funding source(s): The Danish Children's Heart Foundation, Boernehjertefonden.

Effect of seat thickness on peak femoral vein velocity

IntroductionThis study aimed to investigate the effects of different seat thicknesses on lower limb momentum and lower limb blood flow in a narrow enclosed space simulating public places. MethodsWe enrolled 15 female volunteers. We measured the maximum venous blood flow velocity (peak velocity [PV]) of the superficial femoral vein, the range of knee joint movements, and the number of knee joint movements while the subjects sat on the thicker- or thinner-tip seat for 140 min. ResultsThere was a difference in the change rate of PV after 140 min of sitting: thinner-tip seat groups: 22.3% (−31.1 − −13.5%); thinner-tip seat groups: 6.9% (−16.5 − 2.8%) (P < 0.001). There was a significant difference in the range of knee joint motion between the two seats: thicker-tip seat: 24.5° (19.9°–29.1°); thinner-tip seat: 36.6° (29.1°–44.1°) (P = 0.01). There was a significant positive correlation between the change rates of PV and the knee joint range of motion (r = 0.41, P = 0.03). ConclusionsOur findings suggest that a seat structure that does not restrict lower limb movement may help inhibit reductions in lower limb blood flow when sitting for long periods.

Comparison of small symptomatic and asymptomatic abdominal aortic aneurysms based on computational fluid dynamics analysis.

Background:The purpose of this study was to compare the hemodynamic parameters of symptomatic and asymptomatic abdominal aortic aneurysms (AAAs) to explore the risk factors for AAA rupture.Methods:We conducted a retrospective analysis of 26 patients with symptomatic small AAAs and 60 patients with asymptomatic small AAAs. Computational fluid dynamics methods were used to compare hemodynamic characteristics between the symptomatic and asymptomatic groups and to evaluate risk factors for the occurrence of symptomatic AAAs.Results:The maximum diameters in the symptomatic and asymptomatic groups were 49.7 ± 4.94 mm and 48.4 ± 4.55 mm, respectively. Wall shear stress values at turbulent flow regions in the symptomatic and asymptomatic groups were 0.0098 ± 0.0084 Pa versus 0.0174 ± 0.0068 Pa, respectively. Shear stress values at the site with maximal blood flow impact force in the symptomatic and asymptomatic groups were 1.13 ± 0.466 Pa and 2.04 ± 0.42 Pa, respectively. The areas of the intra-luminal thrombus in the section with the maximum diameter in the symptomatic and asymptomatic groups were 952.19 ± 413.53 mm2 versus 646.63 ± 296.88 mm2, respectively.Conclusion:The wall shear stress in the symptomatic group was lower than that in the asymptomatic group.

First phase ejection fraction in aortic stenosis: A useful new measure of early left ventricular systolic dysfunction.

In aortic stenosis (AS), a left ventricular (LV) ejection fraction (EF) <50% or symptoms are class I indications for aortic valve intervention. However, an EF <50% may be too conservative since subendocardial fibrosis may already have developed. An earlier marker of LV systolic dysfunction is therefore needed and first phase EF (EF1) is a promising new candidate. It is the EF measured over early systole to the point of maximum transaortic blood flow. It may be low in the presence of preserved total LV EF since the heart may compensate by recruiting myosin motors in later systole. The EF1 is inversely related to the grade of AS and directly related to markers of subendocardial fibrosis like late gadolinium enhancement on cardiac magnetic resonance scanning. A reduced EF1 (<25%) predicts adverse clinical events better that total EF and global longitudinal strain. We suggest that it is worth exploring as an indication for surgery in patients with asymptomatic severe AS.

The effect of vertebral artery characteristics on cervical discogenic pain and disability

Introduction : Cervical discogenic pain, which is characterized by a stiffness or pain in neck movement, generally occurs as a result of disc degeneration. On the other hand; vascular pathologies of the cervical region, especially vertebrobasilar insufficiency, may give rise to similar findings in patients; it can also be detected simultaneously with cervical disc pathologies. . In this study, it was aimed to investigate whether the circulatory properties of the vertebral arteries have an effect on the neck pain and functional status of the patients.&#x0D; Material and Method: Based on the participants’ medical history, physical examination and radiological examination, sixty five patients were diagnosed with cervical disc herniation. Twenty patients who met the inclusion criteria were completed the study. Vertebral artery and carotid artery doppler ultrasonography was performed in these patients, thus any stenosis or insufficiency in vascular systems of the neck was evaluated. Additionally; vertebral blood flow rate (ml / min),vessel diameter(mm), minimum blood flow velocity (Vmin) and maximum blood flow velocity (Vmax) parameters was measured by doppler ultrasonography. The obtained findings compared with patients' level of pain measured with the "VAS (Visual Analog Scale)" and the level of daily life activities measured by the "Neck Disability Index ". &#x0D; Results: It was detected a statistically significant negative correlation between the VAS score and right vertebral artery diameter (p=0.019, r=-0.518). A significant reverse correlation between the VAS score and right vertebral arterial blood flow rate (p=0.011, r=-0.556) was also observed. No correlation was found between other vertebral artery parameters and VAS score or Neck Disability Index (p&gt;0.05).&#x0D; Conclusion: The findings of this study revealed that there is a correlation between the vertebral artery flow rate and pain level. Clinicians must take into consideration vertebral pathologies in patients with neck pain because of this vital condition may accompany with various musculoskeletal pathologies such as cervical disc herniation.

Association Between Long-Term Exposure to Ambient Air Pollution and Lesion Ischemia in Atherosclerotic Patients

BACKGROUND AND AIM: Air pollution has been associated with coronary artery diseases (CAD) worldwide. The underlying mechanisms are understudied, especially through the coronary stenosis pathway to induce myocardial ischemia. The advances of computed tomography (CT) allows novel quantifications on lesion ischemia. We aim to investigate associations between long-term exposure to air pollution and fractional flow reserve on CT (CT-FFR), a subclinical measure of blood flow limitation to gain insight into potential mechanism. METHODS: CT-FFR, which defines a ratio of maximal myocardial blood flow compared to its normal value (range: 0-100%), was characterized in 1897 patients with atherosclerosis between 2015-2017 from a cohort study. Annual average exposure to air pollutants, including ozone (O3), nitrogen dioxide (NO2), and fine particulate matter (PM2.5), was estimated by high-resolution spatiotemporal exposure model for individual participants. Linear regression models, controlling for potential confounders, were used to assess the association of each air pollutant with CT-FFR. Adjusted logistic regression models were used to estimate associations with prevalence of myocardial ischemia CT-FFR 80%). RESULTS:Participants were on average 60 years old with 62% males. Annual average O3, NO2, PM2.5 were 61, 47 and 60 µg/m3, respectively. Mean CT-FFR value was 77%. In the main analysis, higher level of O3 exposure is associated with smaller CT-FFR value (-1.28%, 95% CI: -2.36, -0.19 per 8 µg/m3), adjusting for risk factors and plaque phenotypes, independent from the effects of exposure to NO2 and PM2.5. No associations were observed for PM2.5 nor for NO2 with CT-FFR or for any exposure metrics with prevalence of myocardial ischemia. CONCLUSIONS:Long-term exposure to O3 is associated with lower CT-FFR value in atherosclerotic patient, indicating higher risk of lesion ischemia. The novel finding needs to be examined broadly among larger population at risk of CAD. KEYWORDS: Air pollution, Cardiovascular diseases, Environmental epidemiology, Outcomes

The feasibility of ultrasound-assisted endovascular laser thrombolysis in an acute rabbit thrombosis model.

This study aimed to test the feasibility of combined ultrasound and laser technique, namely, ultrasound-assisted endovascular laser thrombolysis (USELT), for thrombolysis by conducting in vivo tests in a rabbit thrombosis model. An acute thrombus was created in the right jugular vein of rabbit and then was treated with ultrasound only, laser only, and USELT to dissolve the blood clot. A total of 20 rabbits were used. Out of which, the first three rabbits were used to titrate the laser and ultrasound parameters. Then, five rabbits were treated with ultrasound only, five rabbits were treated with laser only, and seven rabbits were treated with USELT. During USELT, 532-nm laser pulses were delivered endovascularly directly to the clot through a fiber optic, and 0.5MHz ultrasound pulses were applied noninvasively to the same region. A laser fluence of 4 to 12mJ/cm2 and ultrasound amplitude of 1 to 2MPa were used. Recanalization of the jugular vein was assessed by performing ultrasound Doppler imaging immediately after the treatment. The maximum blood flow speed after the treatment as compared to its value before the treatment was used to calculate the blood flow recovery in vessel. The blood flow was fully recovered (100%) in three rabbits, partially recovered in two rabbits (more than 50% and less than 100%) with mean percentage recovery of 69.73% and poorly recovered in two rabbits (<50%) with mean percentage recovery of 6.2% in the USELT group. In contrast, the treatment group with ultrasound or laser alone did not show recanalization of vein in any case, all the five rabbits were poorly/not recovered with a mean percentage recovery of 0%. The USELT technology was shown to effectively dissolve the blood clots in an acute rabbit jugular vein thrombosis model.

Myocardial Perfusion Reserve in Children with Friedreich Ataxia.

Children with Friedreich's ataxia (FA) are at risk of perioperative morbidity and mortality from severe unpredictable heart failure. There is currently no clear way of identifying patients at highest risk. We used myocardial perfusion reserve (MPR), an MRI technique used to assess the maximal myocardial blood flow above baseline, to help determine potential surgical risk in FA subjects. In total, seven children with genetically confirmed FA, ages 8-17years, underwent MPR stress testing using regadenoson. Six of the seven demonstrated impaired endocardial perfusion during coronary hyperemia. The same six were also found to have evidence of ongoing myocardial damage as illustrated by cardiac troponin I leak (range 0.04-0.17ng/mL, normal < 0.03ng/mL). None of the patients had a reduced ejection fraction (range 59-74%) or elevated insulin level (range 2.46-14.23mCU/mL). This retrospective study shows that children with FA develop MPR defects early in the disease process. It also suggests MPR may be a sensitive tool to evaluate underlying cardiac compromise and could be of use in directing surgical management decisions in children with FA.

Clinical Value of Echocardiographic Parameters in Patients with Chronic Heart Failure

Chronic heart failure (CHF) is a major disease that affects the safety of human life. The traditional diagnosis method of chronic heart failure is mainly blood test. At the same time, the conventional treatment of heart failure is not only limited to improve the clinical symptoms of patients, but also can prevent the deterioration of chronic diseases. Systemic adjuvant treatment of heart failure also includes improving the quality of life and regulating the mood of patients. However, the traditional diagnostic methods of chronic heart failure have the disadvantages of incomplete and unreliable diagnostic parameters. Therefore, in view of this situation, this paper will carefully analyze and study the application of ultrasound diagnosis technology in the diagnosis of chronic heart failure, and compare the corresponding diagnostic parameters with conventional blood detection parameters, including ventricular septal thickness, ventricular septal thickness, ventricular septal thickness, end diastolic ventricular posterior wall thickness, ejection dispersion and maximum blood flow velocity. In the experimental part, 50 related patients in a hospital were diagnosed and compared. The experimental results show that the ultrasonic diagnosis technology can reflect the heart function of patients with heart failure more comprehensively and reliably.

An adaptive frequency – Voltage control model for extracorporeal supporting flow regulation in an extracorporeal membrane oxygenation system

Extracorporeal membrane oxygenation (ECMO) is employed to treat critical patients for one to a few days of life support in intensive care units. Venovenous (VV) and venoarterial (VA) ECMO configurations are the most commonly used rescue strategies for temporary cardiac and respiratory function support. However, both ECMO modes sometimes cannot meet a patient’s demands because of (a) less oxygenated blood in either the upper body or lower body, or (b) a deterioration in the patient’s hemodynamic status. Veno-Venoarterial (VVA) ECMO is an upgraded system that provides sufficiently oxygenated blood to the systemic and pulmonary circulation systems. Drainage cannulas and gas flow exchanges are determined to provide the maximum drainage blood flow required by the patient through a servo-regulator that adjusts the motor speed. A generalized regression neural network (GRNN) based estimator is created to automatically estimate the desired pump speed and then provide sufficient drainage flow for temporary life support. To achieve stability flow in an ECMO circuit, a bisection approach algorithm (BAA) is employed to improve the performance of transient responses in step controls and steady state controls. Experimental studies are used to validate the proposed model and it is compared with conventional controllers to indicate good performance in clinical VVA ECMO applications.

Type 2 diabetes impairs vascular responsiveness to nitric oxide, but not the venoarteriolar reflex or post-occlusive reactive hyperaemia in forearm skin.

The venoarteriolar reflex (VAR) is a local mechanism by which vasoconstriction is mediated in response to venous congestion. This response may minimize tissue overperfusion, preventing capillary damage and oedema. Post-occlusive reactive hyperaemia (PORH) is used to assess microvascular function by performing a brief local arterial occlusion resulting in a subsequent rapid transient vasodilation. In the current study, we hypothesized that type 2 diabetes (T2D) attenuates VAR and PORH responses in forearm skin in vivo. In 11 healthy older adults (Control, 58±8years) and 13 older adults with controlled T2D (62±10years), cutaneous blood flow measured by laser-Doppler flowmetry was monitored following a 3-min venous occlusion of 45mmHg that elicited the VAR, followed by a 3-min recovery period and then a 5-min arterial occlusion of 240mmHg that induced PORH. Finally, sodium nitroprusside, a nitric oxide donor, was administered to induce maximum vasodilation. VAR and PORH variables were similar between groups. By contrast, maximal cutaneous blood flow induced by sodium nitroprusside was lower in the T2D group. Taken together, our observations indicate that T2D impairs vascular smooth muscle responsiveness to nitric oxide, but not VAR and PORH in forearm skin.