Reversal Of Blood Flow Research Articles

Time-dependent simulation of blood flow through an abdominal aorta with iliac arteries.

Atherosclerosis is one of the important diseases of the circulatory system because atherosclerotic plaques cause significant disruption of blood flow. Therefore, it is very important to properly understand these processes and skillfully simulate blood flow. In our work, we consider blood flow through an abdominal aorta with iliac arteries, assuming that the right iliac artery is narrowed by an atherosclerotic lesion. Blood flow is simulated using the laminar, standard and standard models. The obtained results show that despite the use of identical initial conditions, the distribution of velocity flow and wall shear stress depends on the choice of flow simulation model. For the model, we obtain higher values of speed and wall shear stress on atherosclerotic plaque than in the other two models. The laminar and models predict larger areas where reverse blood flow occurs in the area behind the atherosclerotic lesion. This effect is associated with negative wall shear stress. These two models give very similar results. The results obtained by us, and those reported in the literature, indicate that model is the most suitable for blood flow analysis.

A Prosthetic Conduit can be Used Safely for TransCarotid Artery Revascularization Under Local Anesthesia in High-Risk Patients.

Surgical management of carotid stenosis has evolved from open carotid endarterectomy (CEA) to include multiple alternative procedures including transfemoral carotid artery stenting (tfCAS) and transcarotid artery stenting. In recent years, Transcarotid Artery Revascularization (TCAR) has emerged as a third option, combining open cut down to the common carotid artery (CCA) with endovascular stenting and neuroprotection via reversal of cerebral blood flow. In this case series, a modified TCAR procedure using a prosthetic conduit was successfully performed exclusively under local anesthesia in a total of 10 patients with carotid artery stenosis, high cardiac risk, and anatomical contraindications to a traditional TCAR.

Eisenmenger syndrome presenting with chronic thromboembolic disease

Eisenmenger syndrome is characterized by the reversal of blood flow due to increased pulmonary vascular resistance. It can be prevented with early diagnosis and surgical treatment. Thromboembolism is a leading cause of death in patients with Eisenmenger syndrome. Pulmonary endarterectomy is the primary treatment, but medical treatments may be considered in inoperable cases. Regular follow-up and a multidisciplinary approach are important for diagnosis and treatment. Lifestyle changes and medical therapy can improve patient's quality of life and prevent complications. Our case is presented because of the chronic thromboembolic disease in addition to the pulmonary hypertension due to the partial atrioventricular septal defect and the management of the treatment.

Clinical efficacy of different androgen deprivation therapies for prostate cancer and evaluation based on dynamic-contrast enhanced magnetic resonance imaging.

To evaluate the clinical efficacy of different androgen deprivation therapies for prostate cancer (PCa) based on dynamic-contrast enhanced magnetic resonance imaging (DCE-MRI). 104 patients with PCa were studied, all of whom were treated with androgen deprivation therapy. The patients were divided into a continuous group (continuous androgen deprivation therapy) and an intermittent group (intermittent androgen deprivation therapy) by random number table method, 52 cases/group. The therapeutic effect and DCE-MRI indices were compared and the relationship between DCE-MRI indices and clinical efficacy and the evaluation value of therapeutic efficacy were analyzed. The objective response rate (ORR) of the intermittent group was higher than that of the continuous group (p < 0.05), and there was no significant difference in disease control rate (DCR) between the two groups (p > 0.05). After treatment, volume transfer coefficient (Ktrans), reverse transfer constant (Kep), volume fraction (Ve), blood volume (BV), and blood flow (BF) in both groups were lowered, and those in the intermittent group were lower than the continuous group (p < 0.05). Ktrans, Kep, Ve, BF, and BV in the ORR group were lower than those in the non-ORR group (p < 0.05). Ktrans, Kep, Ve, BF, and BV were correlated with the therapeutic effect of PCa (p < 0.05). The AUC value of the combined detection of DCE-MRI indices in evaluating the therapeutic effect of PCa was greater than that of each index alone (p < 0.05). Compared with continuous androgen deprivation therapy, intermittent androgen deprivation therapy has better clinical efficacy in the treatment of PCa, and DCE-MRI indices are related to the treatment efficacy of PCa and have an evaluation value.

Echocardiographic features and pathological ultrastructural characteristics of fetal interruption of aortic arch.

Interruption of aortic arch (IAA) is a rare congenital heart disease. This study aims to investigate echocardiographic features and pathological ultrastructural characteristics of fetal IAA and to further analyze its pathological evolution. A retrospective analysis was conducted on prenatal echocardiographic, post-surgical, or autopsy findings of fetuses prenatally diagnosed with IAA. Prenatal echocardiographic tracking was used to observe the internal diameters and Z-scores of different segments of the aortic arch and the changes in the narrowed section. These observations were combined with autopsy and pathological findings to explore the potential intrauterine evolution of IAA and its cytological basis. The study included 34 fetuses with IAA, with 3, 3, and 28 fetuses prenatally diagnosed with aortic arch dysplasia (AAD), coarctation of aorta (CoA), and IAA, respectively. The 3 AAD and 3 CoA fetuses chose termination of pregnancy 1 to 2 weeks after prenatal ultrasound diagnosis, and autopsy confirmed IAA. Among the 28 fetuses prenatally diagnosed with IAA, 6 cases of CoA progressively worsened, eventually evolving into type A IAA as observed through echocardiographic follow-up. The remaining 22 cases were diagnosed as IAA on the first prenatal ultrasound. Postnatal surgery corrected 3 cases, while 27 cases opted for pregnancy termination, and 4 cases resulted in intrauterine death. Echocardiographic features of the fetal IAA included a significantly smaller left ventricle compared with the right or negligible difference on the four-chamber view, a significantly smaller aorta than the pulmonary artery on the three-vessel view, and a lack of connection between the aorta and the descending aorta on the three-vessel-trachea and aortic arch views. The aortic arch appears less curved and more rigid, losing the normal "V" shape between the aorta, ductus arteriosus, and descending aorta. Color Doppler ultrasound showed no continuous blood flow signal at the interruption site, with reversed blood flow visible in the ductus arteriosus. Transmission electron microscopy of 7 IAA fetuses revealed numerous disorganized smooth muscle cells between the elastic membranes near the aortic arch interruption site, significantly increased in number compared with the proximal ascending aorta. The elastic membranes were thicker and more twisted near the interruption site. The interruption area lacked normal endothelial cells and lumen, with only remnants of necrotic endothelial cells, disorganized short and thick elastic membranes, and randomly arranged smooth muscle cells. Prenatal echocardiography is the primary diagnostic tool for fetal IAA. Post-surgical follow-up and autopsy help identify complications and disease characteristics, enhancing diagnostic accuracy. Some fetal IAA may evolve from AAD or CoA, with potential pathogenesis related to ischemia, hypoxia, and migration of ductal constrictive components.

IOT-BASED SMART SALINE LEVEL AND HEALTH MONITORING SYSTEM

The many uses of saline solution include as providing temporary fluids when there is under or no hydration among the trauma cases. In addition, they participate in the control of salt and the levels of electrolytes in the body. To maintain the level of a saline bottle, hospital nurses or aides prime responsibility is to check it on a regular basis. The failure to replace them in time may result in a reversal of blood flow, compromising the patient’s life. An Internet of Things (IoT)-based Smart Saline Level was developed to solve this issue and to provide an automated and efficient solution for remote monitoring. The Proposed system employs Internet of Things (IoT) technology, integrating NodeMCU, a load cell amplifier (HX711), Arduino UNO, Pulse oximeter (MAX 30100) sensor, DHT11 Sensor and a voltage regulator(L7805). The load cell, in combination with the HX711 amplifier, accurately measures the weight of the saline bottle. MAX30100 sensor measures Heart Rate &amp; Oxygen saturation (SPo2) levels in blood. DHT11 Sensor detects the Humidity and Temperature levels. All the data is transmitted to the Arduino UNO, which serves as a master, the NodeMCU facilitates wireless communication, relaying the collected data from the Arduino UNO to the designated IoT cloud platform for remote monitoring.

AYURVEDIC MANAGEMENT OF VARICOSE VEINS WITH SHAMAN CHIKITSA : A CASE REPORT

Varicose veins are defined as dilated, tortuous, elongated superficial veins that cause reversal of blood flow due to valve insufficiency. Varicose veins are more common in the lower extremities due to the upright posture of the body. Varicose veins are similar to Uttana Vatarakta varicose veins in terms of etiology and symptoms. Varicose veins also have close similarities with Siraj Granthi and Siragat Vata. We report a case of a 35-year-old male patient who presented with lower extremity pain from the calf to both legs accompanied by dilated and tortuous veins on the back of the legs, discoloration, itching, and burning. And uncomfortable. The patient was treated with Ayurvedic medications and his symptoms improved significantly. Observations and results were compiled according to the evaluation criteria. The discussion was based on all observations made during the study. Conclusions were drawn based on the results.

Focal hepatic hot spot sign: Clinical image

A 51‐year‐old women was hospitalized to start chemotherapy for small cell lung cancer diagnosed one months earlier. She underwent Computed Tomography (CT) of the chest and abdomen to re‐evaluate the progression of the lung tumour. Contrast-enhanced CT of the chest indicated an invasive anterior left lung tumour that caused an obstruction of the Superior Vena Cava (SVC) (Figure 1). Contrast-enhanced CT of the abdomen revealed an intense focal wedge-shaped homogeneous enhancement area in the quadrate lobe of the liver, which is known as the hot spot sign (Figure 2). Focal hepatic hot spot sign was first described by Ishikawa in 1983. The sign can be observed on technetium 99m (99mTc) Sulphur colloid scans or on contrast, material enhanced CT scans [1]. Hot spot sign is caused by portosystemic venous shunting between the superior vena cava and the left portal vein via the internal mammary and paraumbilical veins along the ligamentum teres, secondary to superior vena cava obstruction. The hot spot is created by areas of focally increased blood flow that result from this shunting [2]. Stanford and colleagues classified SVC syndrome into four types - type I and type II referred as supra-azygous partial and near complete obstruction of SVC with antegrade flow in azygous vein. Type III is defined as complete obstruction of SVC with reversal of azygous blood flow and type IV as complete obstruction of SVC and azygous system with development of chest wall collaterals [3]. This sign has been reported in Budd-Chiari syndrome, the causes of SVC syndrome (neoplasms of the thorax as lung carcinoma and lymphoma, Vasculo‐Behcet’s disease, fibrosing mediastinitis, and luetic aneurysm), and masses of the liver (abscess, haemangioma, focal nodular hyperplasia, and hepatocellular carcinoma) [4].

Electroencephalogram pattern predicting neurological outcomes of children with seizures secondary to abusive head trauma

BackgroundThe clinical presentations of abusive head trauma can abruptly worsen, so the occurrence of seizures and changes of EEG can be variable according to patients’ conditions. Since the changes of EEG background waves reflect the cortical function of children, we aimed to find out whether the timing of EEG background, epileptiform discharges and seizure patterns were associated with the outcomes of patients with AHT. Material and methodsUsing seizure type and acute stage electroencephalographic (EEG) characteristics to assess adverse neurological outcomes in children with seizures secondary to abusive head trauma (AHT). Children who were hospitalized with AHT at a tertiary referral hospital from October 2000 to April 2010 were evaluated retrospectively. A total of 50 children below 6 years of age admitted due to AHT were included. KOSCHI outcome scale was used to evaluate the primary outcome and neurological impairment was used as secondary outcome after 6 months discharge. ResultsChildren with apnea, cardiac arrest, reverse blood flow and skull fracture in clinic had a higher mortality rate even in the no-seizure group (3/5 [60%] vs. 3/45 [6.7%], odds ratio [OR] = 11; 95% CI = 2.3–52; p = 0.025). Seizure occurrence reduced mostly at the second day after admission in seizure groups; but children with persistent seizures for 1 week showed poor neurological outcomes. The occurrence of initial seizure was frequency associated with younger age; focal seizure, diffuse cortical dysfunction in acute-stage EEG, and low Glasgow Coma Scale (GCS) score were significantly related to poor outcomes after 6 months. Diffuse cortical dysfunction was also associated with motor, speech, and cognitive dysfunction. ConclusionsDiffuse cortical dysfunction in acute-stage EEG combined with low GCS score and focal seizure may related to poor outcomes and neurological dysfunctions in children with AHT.

Ultra-fast ultrasound blood flow velocimetry for carotid artery with deep learning

Accurate measurement of blood flow velocity is important for the prevention and early diagnosis of atherosclerosis. However, due to the uncertainty of parameter settings, the autocorrelation velocimetry methods based on clutter filtering are prone to incorrectly filter out the near-wall blood flow signal, resulting in poor velocimetric accuracy. In addition, the Doppler coherent compounding acts as a low-pass filter, which also leads to low values of blood flow velocity estimated by the above methods. Motivated by this status quo, here we propose a deep learning estimator that combines clutter filtering and blood flow velocimetry based on the adaptive property of one-dimensional convolutional neural network (1DCNN). The estimator is operated by first extracting the blood flow signal from the original Doppler echo signal through an affine transformation of the 1D convolution, and then converting the extracted signal into the desired blood flow velocity using a linear transformation function. The effectiveness of the proposed method is verified by simulation as well as in vivo carotid artery data. Compared with typical velocimetry methods such as high-pass filtering (HPF) and singular value decomposition (SVD), the results show that the normalized root means square error (NRMSE) obtained by 1DCNN is reduced by 54.99 % and 53.50 % for forward blood flow velocimetry, and 70.99 % and 69.50 % for reverse blood flow velocimetry, respectively. Consistently, the in vivo measurements demonstrate that the goodness-of-fit of the proposed estimator is improved by 8.72 % and 4.74 % for five subjects. Moreover, the estimation time consumed by 1DCNN is greatly reduced, which costs only 2.91 % of the time of HPF and 12.83 % of the time of SVD. In conclusion, the proposed estimator is a better alternative to the current blood flow velocimetry, and is capable of providing more accurate diagnosis information for vascular diseases in clinical applications.

DEVELOPMENT OF SEAMED COMPRESSION SOCKS AND COMPARISON WITH CLASS I SOCKS USING EXISTING MATHEMATICAL MODELS

Compression therapy is an important method for treating venous diseases such as venous edema and venous hypertension. Regular compression therapy's main objective is to diminish leg swelling by controlling blood flow and avoiding the recurrence of reversible blood flow. Compression socks are often recommended as therapeutic garments. In this study, a seamed compression sock was developed using fabric with an interlock knit structure. Three other sock samples were produced by using circular knitting MERZ CC4 model machine for comparison. The results demonstrate that the developed sock meets all the requirements of compression class I. Statistical analysis reveals that fabric parameters, particularly fabric weight, effectively explain compression pressure intensity according to the values of coefficient of determination, coefficient of correlation (r), and means sum of square errors (MSE). In this work, Laplace's Law and a few preexisting mathematical models were used to calculate the compression pressure of both standard compression socks and socks with seams, with results that were essentially similar. The points of data are tightly clustered around line of regression, showing that there is little variation in the compression pressure for socks with seams.

Food intolerance in premature babies: possibilities of additional diagnostics

Due to the immaturity of the digestive system and gastrointestinal motility the preterm infants have a critical challenge in establishing adequate enteral nutrition, which is a frequent cause of gastrointestinal complications such as food intolerance and necrotizing enterocolitis. Modern clinical methods of assessing the maturity of the intestines and the child's readiness for enteral nutrition are subjective, this slows down the expansion of enteral nutrition, increases the duration of parenteral nutrition, and accordingly , period of a child`s hospitalizing. Objective methods of diagnosis are needed, which would contribute to the effective diagnosis and monitoring of food intolerance in preterm infants. Therefore, the purpose of our review was to search and summarize literature data on objective methods of diagnosing impaired food tolerance in premature baby, which could to provide daily monitoring, would be safe, cost-effective and easily accessible. Results and their discussion. Accordingly, three leading and most promising methods of examining the newborns gastrointestinal tract were analyzed. The were ultrasound examination (absence or reverse diastolic blood flow in the umbilical artery, high pulsation index in the fetal venous duct, indicators of blood flow in the upper mesenteric artery of the newborn), near-infrared spectroscopy (estimation of oxygen saturation of splanchnic tissue), and auscultation of intestinal sounds (phonoenterogram). Each of these methods has advantages and disadvantages, but to solve these existing problems, there has been recently an increasing amount of research on the bowel sounds using (namely their computerized assessment) as a new diagnostic tool. New research and further study of intestinal murmurs in premature newborns of different gestational ages with the development of clear criteria for data interpretation are needed to assess the maturity of the gastrointestinal tract, to create a diagnosis plan of food intolerance, and to develop an algorithm for early intervention.

Intrahepatic Venous Collateral Circulation and Reverse Blood Flow After Main Hepatic Vein Obstruction: A Case Report with Literature Review

Intrahepatic Venous Collateral Circulation and Reverse Blood Flow After Main Hepatic Vein Obstruction: A Case Report with Literature Review

Computational Evaluation of IABP, Impella 2.5, TandemHeart and Combined IABP and Impella 2.5 Support in Cardiogenic Shock

Cardiogenic shock is a life-threatening condition consisting of low cardiac output status leading to end-organ hypoperfusion following either acute left or right ventricular failure or decompensation of chronic heart failure. Partial or failed response to inotropic support in the acute phase may require the use of mechanical circulatory support. Although patients supported with different devices such as an IABP, Impella 2.5, or TandemHeart experience stability in the short term, the haemodynamic benefits of each device remain unclear. The aim of this study is to present a direct comparison of an IABP, Impella 2.5, TandemHeart, and combined IABP and Impella 2.5 support in cardiogenic shock to evaluate haemodynamic variables and left ventricular unloading using cardiovascular system modelling and simulation in terms of cardiac function, systemic, pulmonary, cardiac, and cerebral circulations. The simulation results showed that the IABP had a relatively low effect on the haemodynamic variables. Although both Impella 2.5 and TandemHeart improved the total blood flow rates, as well as coronary and cerebral perfusion with the increasing pump operating speed, TandemHeart had a more profound effect on the haemodynamic variables. Combining the IABP and Impella 2.5 also improved the haemodynamics, although at the expense of reverse blood flow in the cerebral circulation. Simulation results showed that TandemHeart support might have a more beneficial effect on the haemodynamics and left ventricular energetics in comparison to the IABP and Impella 2.5. Nevertheless, the combined use of the IABP and Impella 2.5 for short-term support may be considered an appropriate alternative.

Carotid artery dissections from transcarotid artery revascularization as reported by the Food and Drug Administration.

Transcarotid artery revascularization (TCAR) is a hybrid procedure that allows reversal of blood flow away from the brain while placing a stent through direct surgical access of the common carotid artery. It has been shown to have a lower risk of perioperative stroke compared with any prospective trial of transfemoral carotid artery stenting. However, intraoperative injuries related to the procedure and its management are not well characterized. One of the intraoperative complications seen in TCAR is iatrogenic carotid artery dissection (CD). We aim to add qualitative insight in further characterizing CDs and its management in this emerging technology. The Food and Drug Administration (FDA) maintains the Manufacturer and User Facility Device Experience (MAUDE) database for surveillance of all medical devices approved for use. This database was queried for all cases associated with Silk Road Medical's ENROUTE Transcarotid Neuroprotection System from September 2016 to October 2020. Case narratives related to CD were individually analyzed to determine time of injury (intraoperative, recovery, and post-discharge follow-up). CD reporting was further analyzed for the associated procedural event at the time of injury, number of access attempts to CD repair, and type of CD repair. Reports associated with CD repair were further categorized into endovascular repair and open surgical repair. Of the 115 unique adverse events in the database, there were 58 CDs. Most were identified intraoperatively (n = 55), while three were incidentally found postoperatively. Overall, sheath placement was the most common procedural event attributed to CD (N = 34). There was adequate narrative information about CD repair in 54 patients. Intraoperative repair was performed in 52 cases and two were repaired after post-discharge follow-up imaging was performed.Among CDs that did not require additional access to engage the true lumen, the proportion of endovascular repair (62.5%) was significantly higher (p = .044) compared to the proportion of open surgical repair (37.5%). However, the proportion of open surgical repair (75%) was significantly higher than the proportion of endovascular repair (25%) in CDs with persistent failure to engage the true lumen despite ≥2 access attempts (p = .039). CD is the most common injury related to TCAR as reported on MAUDE. The most commonly reported procedural event associated with CD was sheath placement. The rate of intraoperative endovascular and open surgical CD repair was associated with whether the access to the true lumen of the carotid artery required additional access attempts or not. This should add qualitative insight among the vascular surgery community regarding intraoperative management of CDs from a TCAR procedure.

Fluid-structure interaction study of hemodynamics and its biomechanical influence on carotid artery atherosclerotic plaque deposits

Atherosclerotic plaque deposits are common causes of blood flow disruption in the carotid artery bifurcation and the associated fluid mechanics has been extensively studied using Computational Fluid Dynamics (CFD) and Fluid Structure Interaction (FSI). However, the elastic responses of plaques to hemodynamics in the carotid artery bifurcation has not been deeply studied using either of the above-mentioned numerical techniques. In this study, a two-way FSI study was coupled with CFD technique, using Arbitrary-Lagrangian-Eulerian method, to study the biomechanics of blood flow on nonlinear and hyperelastic calcified plaque deposits in a realistic geometry of the carotid sinus. FSI parameters such as total mesh displacement and von Misses stress on the plaque, as well as flow velocity and blood pressure around the plaques, were analyzed and compared to variables such as velocity streamline, pressure and wall shear stress obtained from CFD simulation in a healthy model. The blood flow simulations reveal complete reversed blood flow behavior in the internal carotid artery, ICAs and external carotid artery, ECAs for both cases. In particular, this study suggests that plaques, irrespective of the masses, possess a high yielding response to hemodynamic forces at the attaching edges, while the surfaces are vulnerable to rupture.

Long-Term Outcome of Carotid-Subclavian Bypass in the Management of Coronary-Subclavian Steal Syndrome.

The presence of a significant left subclavian artery stenosis may occasionally lead to blood flow reversal through a LIMA-to-coronary artery bypass graft during left arm exertion; with "stealing" of myocardial blood supply. The aim of this study was to review our experience with carotid-subclavian bypass in patients with post-CABG coronary-subclavian steal syndrome. This is a retrospective review of all patients who underwent carotid-subclavian bypass grafting for post-CABG coronary-subclavian steal syndrome at Mainz University Hospital between 2006 and 2015. Cases were identified in our institutional database, and data were retrieved from surgical records, imaging studies, and follow-up records. Nine patients (all males, mean age of 69.1years) underwent surgical treatment for post-CABG coronary-subclavian steal syndrome. Medium interval between original CABG and carotid-subclavian bypass grafting was 86.1months. There were no perioperative deaths, strokes or myocardial infarctions. At a mean follow-up period of 79.9months, all patients remained asymptomatic and all carotid-subclavian bypass grafts remained patent. One patient required stenting of a common carotid artery stenosis proximal to the graft anastomosis site, and coronary artery stenting was required in four patients in regions other than those supplied by the patent LIMA graft. Carotid-subclavian bypass surgery is a safe treatment option even in patients with multivessel disease and severe comorbidities and should be taken into consideration in patients who are deemed fit for surgery and those who would benefit from the excellent long-term patency rates.

Hybrid surgery recanalization for high-level chronic internal carotid artery occlusion.

Although endovascular recanalization is considered a more effective treatment for chronic internal carotid artery occlusion (CICAO), the success rate of complex CICAO remains inadequate. We present hybrid surgery (carotid endarterectomy combined with carotid stenting) for complex CICAO and explore the influential factors and effects of hybrid surgery recanalization. We retrospectively analyzed the clinical, imaging, and follow-up data of 22 patients with complex CICAO treated by hybrid surgery at the Zhongnan Hospital of Wuhan University from December 2016 to December 2020. We also summarize the technical points related to hybrid surgery recanalization. A total of 22 patients with complex CICAO underwent hybrid surgery recanalization. There were no postoperative deaths in all patients after hybrid surgery recanalization. Nineteen patients successfully underwent recanalization with a success rate of 86.4% and three cases with a failure rate of 13.6%. Patients were divided into success and failure groups. Significantly different radiographic classification of lesions was observed between the success group and the failure group (P = 0.019). The rates of CICAO with reverse ophthalmic artery blood flow in the internal carotid artery (ICA) preoperatively were 94.7% in the success group and 33.3% in the failure group (P = 0.038). Three cases of hybrid surgery recanalization failure were transferred for EC-IC bypass and had good neurological recovery. Postoperative average KPS scores of the 19 patients were improved compared to the preoperative ones (P < 0.001). Hybrid surgery for complex CICAO is safe and effective with a high recanalization rate. The recanalization rate is related to whether the occluded segment surpasses the ophthalmic artery.

Remodeling of the cardiovascular hemodynamic environment by lower limb heat exposure: A computational fluid dynamic study

BackgroundLower limb heat exposure (LLHE) is a promising strategy for the daily management of cardiovascular health because of its non-pharmaceutical advantages. To support the application of this strategy in cardiovascular protection, we examined its impact on the global hemodynamic environment. MethodsSkin blood flow (SBF) of eight locations on the lower limbs was measured before and after LLHE (40 °C and 44 °C) in ten healthy subjects by using a laser Doppler flowmeter. A closed-loop model of circulation uses changes in SBF to quantify the influence of LLHE on the blood flow of the arterial trunk (from ascending aorta to the femoral artery) and visceral branches (coronary, celiac, renal, and mesenteric arteries). ResultsThe SBF in all locations tested on the lower limbs increased significantly (p<0.001) with LLHE and a 3.39-fold and 7.40-fold increase in mean SBF were observed under 40 °C and 44 °C conditions, respectively. In the model, the peak (3.9–25.1%), end-diastolic (13.7–107.3%), and mean blood flow (8.5–86.5%) in the arterial trunk increased with the increase in temperature, but the retrograde flow in the thoracic aorta and abdominal aorta Ⅰ increased at least twice in the diastolic period. Furthermore, LLHE also increased the blood flow of the visceral branches (2.5–20.7%). ConclusionThese findings suggest that LLHE is expected to be a daily strategy for enhancing the functions of both the arterial trunk and visceral arteries, but the increased blood flow reversal in the thoracic and abdominal aortas warrants further investigation.

Dialysis Access-Associated Steal Syndrome and Management.

Dialysis-associated steal syndrome (DASS) occurs in 1-8% of hemodialysis patients with arteriovenous (AV) access. Major risk factors include use of the brachial artery for access creation, female sex, diabetes, and age > 60years. DASS carries severe patient morbidity including tissue or limb loss if not recognized and managed promptly, as well as increased mortality. Diagnosis of DASS requires a directed history and physical exam supported by non-invasive testing. Prior to definitive therapy, detailed arteriography, fistulography, and flow measurements are performed to delineate underlying etiologies and guide management. To optimize success, DASS treatment should be individualized according to access location, underlying vascular disease, flow dynamics, and provider expertise. Possible causes of DASS include extremity inflow or outflow arterial occlusive disease, high AV access flow rate, and reversal of distal extremity arterial blood flow; DASS may also exist without any of the prior features. Depending on the DASS etiology, various endovascular and/or surgical interventions should be considered. Regardless, in the majority of patients presenting with DASS, access preservation can be achieved.