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Perioperative renal and myocardial protection primarily depends on preoperative prediction tools, along with intraoperative optimization of cardiac output (CO) and mean arterial pressure (MAP). We hypothesise that monitoring the intraoperative global afterload angle (GALA), a proxy of ventricular afterload derived from the velocity pressure (VP) loop, could better predict changes in postoperative biomarkers than the recommended traditional MAP and CO. This retrospective monocentric study included patients programmed for neurosurgery with continuous VP loop monitoring. Patients with hemodynamic instability were excluded. Those presenting a 1-day post-surgery increase in creatinine, B-type natriuretic peptide, or troponin Ic us were labelled Bio+, Bio− otherwise. Demographics, intra-operative data, and comorbidities were considered as covariates. The study aimed to determine if intraoperative GALA monitoring could predict early postoperative biomarker disruption. From November 2018 to November 2020, 86 patients were analysed (Bio+/Bio− = 47/39). Bio+ patients were significantly older (62 [54−69] vs. 42 [34−57] years, p < 0.0001), More often hypertensive (25% vs. 9%, p = 0.009), and more frequently treated with antihypertensive drugs (31.9% vs. 7.7%, p = 0.013). GALA was significantly larger in Bio+ patients (40 [31−56] vs. 23 [19–29] °, p < 0.0001), while CO, MAP, and cumulative time spent <65mmHg were similar between groups. GALA exhibited strong predictive performances for postoperative biological deterioration (AUC = 0.88 [0.80−0.95]), significantly outperforming MAP (MAP AUC = 0.55 [0.43−0.68], p < 0.0001). GALA under general anaesthesia prove more effective in detecting patients at risk of early cardiac or renal biological deterioration, compared to classical hemodynamic parameters. [ABSTRACT FROM AUTHOR]

BackgroundIt remains to be established to what extent physical activity (PA) levels among individuals are independently associated with deviations from the “optimal” state of the arterial system. Accelerometers have been proposed as means to obtain reliable, objective, and more comprehensive data of PA. Decisions at the time of data collection/processing could influence the association between accelerometry-derived indices and arterial properties.Objectives(i) To identify to what extent the strength of association between arterial properties and accelerometer-derived indices depend on the recording site and/or the epoch length; (ii) to determine whether some arterial characteristics (hemodynamic vs. structural vs. functional) or regions (elastic vs. transitional vs. muscular arteries; central vs. peripheral) have higher levels of association with accelerometry-derived indices.MethodsPhysical activity (PA), cardiovascular risk factors (CRFs), and cardiovascular properties were evaluated in 60 volunteers (general population; age: 23–62 years; women: 43%). PA was measured daily for 7 days (free-living situation; triaxial-accelerometers ActiGraph-GT3X+; hip and wrist; “Worn-to-wrist” option) and raw data was converted at epoch lengths of 1, 5, 10, 30, and 60-s. PA-related energy expenditure, daily time in moderate-to-vigorous PA, steps/minute, and counts-per-minute for vector magnitude were calculated. The cardiovascular evaluation included hemodynamic (central and peripheral pressure), structural (diameters and intima-media thickness), and functional (local and regional stiffness) parameters of carotids, femoral, and brachial arteries, and carotid-femoral and carotid-radial pathways. Arterial z-scores were obtained using age-related equations derived from healthy participants not exposed to CRFs (n = 1,688; age: 2–84 years; female: 51.2%) to evaluate at which degree each parameter deviates from the “optimal” value.MethodsIn general, hip recordings outperformed those obtained on the wrist regarding the strength of association with arterial parameters. Accelerometer-derived indices and their association with arterial properties vary depending on the recording site and epoch length. PA indices are stronger associated with functional (local) than structural variables and with central than peripheral arteries.ConclusionsRegardless of the PA index, there were independent associations with central artery characteristics, which reinforces that these territories would be the most related to PA levels. Differences in data acquisition and processing could lead to differences in conclusions when addressing the association between accelerometer-derived indices and the cardiovascular system.

Background & Objective: Stroke is one of the leading causes of death. It is also one of the most important factors of long-term disability. We aimed to reveal the relationship of the lunar cycle and seasonality with stroke characteristics. Methods: Data, including the demographic characteristics of the patients, stroke types, stroke severity, etiological factors, accompanying diseases, intensive care needs, and mortality rate were evaluated, recorded, and compared according to seasonality and lunar phases. Results: The study included 538 patients. The stroke type of 468 patients was ischemic. The stroke severity of 231 patients was determined as minor. The ischemic stroke rate was higher in winter than in spring and summer. In spring, the rate of severe stroke was lower than in summer and winter. Posterior system strokes were found at a higher rate in the summer months. During the winter months, middle cerebral artery infarctions were detected more frequently. The intensive care needs of the patients were observed mostly in summer and winter in ischemic stroke patients. When the National Institutes of Health Stroke Scale (NIHSS) scores were compared according to season, no significant difference was found between the groups. There was also no significant difference in gender, age, stroke severity, involved arterial system, etiology, and NIHSS score according to moon phases. But the transient ischemic attack (TIA) rate was higher in the full moon than in the last quarter moon. Conclusion: Seasonal variations may affect ischemic stroke characteristics, such as type, severity and involved arterial system, but in our study, the lunar cycle was not found related to the investigated features. [ABSTRACT FROM AUTHOR]

Liver plays an important role in many events such as bile production, blood filtration and metabolic functions. The liver is supplied by the hepatic arterial system. The hepatic arterial system anatomy has a variable structure and the rate of variation is high. In our study, we aimed to determine the diameters and variation of the arteries supplying the liver with multidetector computed tomography images. In this study, hepatic arterial system variations of 500 cases whose abdominal region was imaged with multidetector computed tomography were evaluated and the diameters of the related arteries were measured. The mean diameters of classical and variational anatomy were determined in this study. According to mean measurements of classical and variational anatomy were abdominal aorta 21.95 mm, celiac artery 7.2 mm, common hepatic artery 4.3 mm, proper hepatic artery 2.93 mm, right hepatic artery 2.92 mm, left hepatic artery 2.51 mm and abdominal aorta 21.85 mm, celiac artery 6.99 mm, common hepatic artery 5.07 mm, proper hepatic artery 3.83 mm, right hepatic artery 2.87 mm ve left hepatic artery 2.09 mm respectively. When evaluated in terms of variations, 85.6 % of the cases had branching according to Type I, 14.4 % of the cases had different branching patterns. Type III (87.5 %) was the most observed variation among them. As a result of the study, it was determined that the arterial diameters vary according to the state of variation and that the arterial diameter of men are greater than that of women. [ABSTRACT FROM AUTHOR]

Highlights • A novel hybrid Windkessel-Womersley (WK-W) coupled mathematical model for the study of pulsatile blood flow in the arterial system is proposed in this article. • The model has been applied and validated using several aortic pressure and flow rate data acquired from different species such as, humans, dogs and pigs. • The WK-W model was able to accurately reconstruct arterial input impedance and to calculate the axial velocity in the aorta and time-varying wall shear stress and frictional pressure drop. • The hybrid WK-W model has the capability to predict the pulsed wave velocity, which is not possible to obtain when using the classical Windkessel models. • This hybrid model shows a great potential to be used in clinical practice, as well as in the basic cardiovascular mechanics research. Abstract A hybrid Windkessel-Womersley (WK-W) coupled mathematical model for the study of pulsatile blood flow in the arterial system is proposed in this article. The model consists of the Windkessel-type proximal and distal compartments connected by a tube to represent the aorta. The blood flow in the aorta is described by the Womersley solution of the simplified Navier-Stokes equations. In addition, we defined a 6-elements Windkessel model (WK6) in which the blood flow in the connecting tube is modeled by the one-dimensional unsteady Bernoulli equation. Both models have been applied and validated using several aortic pressure and flow rate data acquired from different species such as, humans, dogs and pigs. The results have shown that, both models were able to accurately reconstruct arterial input impedance, however, only the WK-W model was able to calculate the radial distribution of the axial velocity in the aorta and consequently the model predicts the time-varying wall shear stress, and frictional pressure drop during the cardiac cycle more accurately. Additionally, the hybrid WK-W model has the capability to predict the pulsed wave velocity, which is also not possible to obtain when using the classical Windkessel models. Moreover, the values of WK-W model parameters have found to fall in the physiologically realistic range of values, therefore it seems that this hybrid model shows a great potential to be used in clinical practice, as well as in the basic cardiovascular mechanics research. [ABSTRACT FROM AUTHOR]

A model of the nonsymmetrical arterial tree was analyzed. The arterial branching model was based on the principle of the electromechanical analogy. The nonsymmetrical arterial tree was divided to 7 arterial generations, starting from larger arteries towards small arteries and arterioles. For each generation the resonant frequency and the transfer function were calculated and there are presented the pressure simulation results for each arterial generation. Terminal segments were determined regarding to calculation of the resonant frequencies and the transfer functions and simulation results.

Introduction: The existing evidence indicates that primary prevention of atherosclerotic disease should begin in childhood. Detection of children and adolescents at risk for atherosclerosis may allow early intervention to decrease the atherosclerotic process, thereby preventing or delaying cardiovascular disease. Vascular reactivity (VR) is altered even by early atherosclerosis. Obesity is a main cardiovascular risk factor (CVRF) observed in childhood. If childhood obesity associates impaired macro and/or micro VR is controversial. Aims: To characterize macro and micro VR analyzing the stimulus and vascular response temporal profiles in children and adolescents considering their body mass index (BMI); and to assess potential associations between subjects' characteristics and the hyperemic stimulus and/or VR. Methods: Healthy subjects (n = 99, age 5-17 years, female 46%) were included. Considering the BMI, normal, overweight and obese groups were defined. CVRF exposure was assessed. Brachial flow-mediated dilation and reactive hyperemia, associated with transient ischemia (forearm cuff-inflation) were evaluated. Diameter, flow velocities, resistive indexes and shear-stress were determined before, during and after cuff-release. Complimentary VR indexes were computed. Aortic stiffness and aortic and brachial blood pressure were determined. Results: Obese showed the lowest and slowest macrovascular response (p < 0.05). Micro VR was not associated with obesity. Higher aortic stiffness levels were associated with slower macrovascular responses (p < 0.05). Conclusion: Childhood obesity associates not only reduced, but also slowed macrovascular reactivity. Microvascular response to transient ischemia is preserved in obese children. Macro and microvascular responses would be non-associated phenomena in childhood. During childhood, VR dynamics would depend on the arterial stiffness. [ABSTRACT FROM AUTHOR]

The article deals with the design of an electrical model of variable segments of a non-symmetrical tree of small arteries This model can be used to simulate the blood pressure and flow. Peripheral arterial resistance changes are modelled by an exponentially dependent resistor. By modulating the capacitor value, we can model the arterial wall properties which depend on the arterial pressure. Simulations are performed in which vasoconstriction and vasodilation were modelled by varying the transmural pressure. As a result, we can observe the changes in the blood pressure for each arterial generation. [ABSTRACT FROM AUTHOR]

Aim. To investigate principal interrelations between heart, arterial and venous parameters, characterizing the common process of cardiovascular system (CVS) remodeling during arterial hypertension (AH) development and progression.Material and methods. The study included 184 patients with primary AH. CVS structure and function were assessed at baseline and after treatment with antihypertensive medications (AHM).Results. The module approach to AH structural and hemodynamic type description is proposed. Modern AHM are studied in regard to their venotropic action, effects on orthostatic tolerance and interrelations between structural and functional parameters of CVS components in AH patients. Mathematical algorithms assessing modern AHM potential for individual patients, taking into account baseline clinical, functional, structural and hemodynamic parameters, are presented.Conclusion. Antihypertensive therapy could be optimized by taking into consideration modern AHM effects on individual CVS components and their interrelations in AH patients.

The blood flow in human arterial system can be considered as a fluid dynamics problem. Simulation of blood flow in the arterial network system will provide a better understanding of the physiology of human body. Hence, hemodynamics play an important role in the development and progression of arterial stenosis, leading to the malfunctioning of cardiovascular system. Simulation studies of blood flow in the diseased condition can diagonise the health problem easily and also have many applications in the areas such as surgical planning and design of medical devices. This paper presents a review on the existing scenario of the simulation studies of blood flow, starting with a brief overview of the structure and function of arteries and veins followed by a discussion on pressure wave propagation, blood flow models and Fluid Structure Interaction in the arterial system. [ABSTRACT FROM AUTHOR]

Modeling of the cardiovascular system is challenging, but it has the potential to further advance our understanding of normal and pathological conditions. Morphology and function are closely related. The arterial system provides steady blood flow to each organ and damps out wave fluctuations as a consequence of intermittent ventricular ejection. These actions can be approached separately in terms of mathematical relationships between pressure and flow. Lumped parameter models are helpful for the study of the interactions between the heart and the arterial system. The arterial windkessel model still plays a significant role despite its limitations. This review aims to discuss the model and its modifications and derive the fundamental equations by applying electric circuits theory. In addition, its role during left ventricular assist device assistance is explored and discussed in relation to rotary blood pumps. [ABSTRACT FROM AUTHOR]

The vascular system is one of the earliest recognized anatomical systems. It is composed of 3 parts; arterial, capillary, and venous, each with their own unique anatomy and physiology. Blood flow through this system is compromised in aging, atherosclerosis and peripheral vascular disease, and the practicing anesthesiologist must understand both the physiology and pathophysiology of the vascular tree., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Age is the dominant risk factor for cardiovascular diseases. Understanding the coupling between the left ventricle (LV) and arterial system, termed arterial-ventricular coupling (EA/ELV), provides important mechanistic insights into the complex cardiovascular system and its changes with aging in the absence and presence of disease. EA/ELV can be indexed by the ratio of effective arterial elastance (EA; a measure of the net arterial load exerted on the left ventricle) to left ventricular end-systolic elastance (ELV; a load-independent measure of left ventricular chamber performance). At rest, in healthy individuals, EA/ELV is maintained within a narrow range, which allows the cardiovascular system to optimize energetic efficiency at the expense of mechanical efficacy. The age-associated alterations to arterial structure and function, including diameter, wall thickness, wall stiffness, and endothelial dysfunction, contribute to a gradual increase in resting EA with age. Remarkably there is a corresponding increase in resting ELV with age due to alterations to LV remodeling (loss in myocyte number, increased collagen) and function. During dynamic exercise there is an acute mismatch between the arterial and ventricular systems due to a disproportionate increase in ELV (approximately 200%) compared to EA (approximately 40%), to ensure that sufficient cardiac performance is achieved to meet the increased energetic requirements of the body. As a result EA/ELV decreases from an average of 0.58 to 0.34, and 0.52 to 0.27 in men and women, respectively. However, with advancing age the reduction in EA/ELV to acute maximal exercise is blunted, due to a blunted ELV. In this review, we provide an overview of the concept of EA/ELV, and examine the effects of age in the absence and presence of disease on EA/ELV and its functional consequences, and potential therapeutic interventions.

BACKGROUND Although multiple studies demonstrate benefits of high field imaging of cerebrovasculature, a detailed quantitative analysis of complete cerebrovascular system is unavailable. To compare quality of MR angiography (MRA) acquisitions at various field strengths, we used 3-dimensional (3D) geometric cerebrovascular models extracted from 1.5T/3T/7T scans. METHODS The 3D cerebrovascular models were compared in volume, length, and number of branches. A relationship between the vascular length and volume was statistically derived. Acquisition performance was benchmarked against the maximum volume at infinitive length. RESULTS The numbers of vessels discernible on 1.5T/3T/7T are 138/363/907. 3T shows 3.3(1.9) and 7T 1.2(9.1) times more arteries (veins) than 1.5T. The vascular lengths and volumes at 1.5T/3T/7T are 3.7/12.5/22.7 m and 15.8/26.6/28.0 cm3. For arteries: 3T-1.5T gain is very high in length, high in volume; 7T-3T gain is medium in length, small in volume. For veins: 3T-1.5T gain is moderate in length, high in volume; 7T-3T gain is very high in length, moderate in volume. 1.5T shows merely half of vascular volume. At 3T 6%, while at 7T only 1% of vascular volume is missing. CONCLUSION Our approach differs from standard approaches based on visual assessment and signal (contrast)-to-noise ratio. It also measures absolute acquisition performance, provides a unique length-volume relationship, and predicts length/volume for intermediate teslages. [ABSTRACT FROM AUTHOR]

Age is the dominant risk factor for cardiovascular diseases. Understanding the coupling between the left ventricle (LV) and arterial system, termed arterial-ventricular coupling (EA/ELV), provides important mechanistic insights into the complex cardiovascular system and its changes with aging in the absence and presence of disease. EA/ELV can be indexed by the ratio of effective arterial elastance (EA; a measure of the net arterial load exerted on the LV) to left ventricular end-systolic elastance (ELV; a load-independent measure of left ventricular chamber performance). Age-associated alterations in arterial structure and function, including diameter, wall thickness, wall stiffness, and endothelial dysfunction, contribute to a gradual increase in resting EA with age. Remarkably there is a corresponding increase in resting ELV with age, due to alterations to LV remodeling (loss in myocyte number, increased collagen) and function. These age-adaptations at rest likely occur, at least, in response to the age-associated increase in EA and ensure that EA/ELV is closely maintained within a narrow range, allowing for optimal energetic efficiency at the expense of mechanical efficacy. This optimal coupling at rest is also maintained when aging is accompanied by the presence of hypertension, and obesity, despite further increases in EA and ELV in these conditions. In contrast, in heart failure patients with either reduced or preserved ejection fraction, EA/ELV at rest is impaired. During dynamic exercise, EA/ELV decreases, due to an acute mismatch between the arterial and ventricular systems as ELV increases disproportionate compared to EA (≈200 vs. 40%), to ensure that sufficient cardiac performance is achieved to meet the increased energetic requirements of the body. However, with advancing age the reduction in EA/ELV during acute maximal exercise is blunted, due to a blunted increase ELV. This impaired EA/ELV is further amplified in the presence of disease, and may explain, in part, the reduced cardiovascular functional capacity with age and disease. Thus, although increased stiffness of the arteries itself has important physiological and clinical relevance, such changes also have major implications on the heart, and vice versa, and the manner in the way they interact has important ramifications on cardiovascular function both at rest and during exercise. Examination of the alterations in arterial-ventricular coupling with aging and disease can yield mechanistic insights into the pathophysiology of these conditions and increase the effectiveness of current therapeutic interventions. [ABSTRACT FROM AUTHOR]

The process of control of the respiratory system is one of the most important tasks in physiology of respiration. The role of blood partial pressure in our body system is very crucial because it depends on the heart rate and ventilation. The construction of a model and its analysis are actually linked with understanding the nature of the mechanisms, including physiological mechanisms that satisfy the need of living organism. In the present paper we study the blood partial pressure of our body system mainly the arterial system and venous system. Two nonlinear coupled ordinary differential equations have used associated to arterial pressure and venous Pressure. The solution of the system of non linear coupled ordinary differential equations numerically is obtained using fourth order Runge kutta method. [ABSTRACT FROM AUTHOR]

Abstract: Although there exist some reference and stereotactic anatomical human brain atlases, there is no equivalent cerebrovascular atlas. A 3D reference atlas of the human cerebrovasculature that is interactive, stereotactic, very detailed, completely parcellated, fully labeled, extendable, dissectible, deformable, and user friendly, is needed in education, training, research, and clinical applications. We constructed a sophisticated and very detailed cerebrovascular atlas with 1325 vascular segments, the smallest of 80μm in diameter. The atlas was created from multiple 3 and 7T scans by employing tools and methods developed in our lab. In contrast to a sort of “sampled” vascular geometry cited in the literature, we provide information about the “continuous” geometry of the vascular model measurable in 3D at every location and along any vascular segment for both hemispheres. This cerebrovascular atlas was validated taking into account domain knowledge from various fields including angiography, neurosurgery, neuroradiology, (clinical) neuroanatomy, and terminology. Validation was considered as a confirmation of the created vascular model to a typical (conventional) cerebrovascular system with nearly average dimensions. It was done in terms of vessel subdivision, origin, course, surrounding anatomy, patterns, length, diameter, and branches. This validation demonstrates that the constructed cerebrovascular model generally represents a normal, typical cerebrovasculature with its dimensions close to average. This 7T atlas along with the vascular model is a rich source of knowledge about the human cerebrovasculature. The atlas is applicable in education, research, and clinical applications; it has already been applied in deep brain stimulation. [Copyright &y& Elsevier]

Individually, the metabolic demands of digestion or movement can be fully supported by elevations in cardiovascular performance, but when occurring simultaneously, vascular perfusion may have to be prioritized to either the gut or skeletal muscles. Burmese pythons (Python molurus) experience similar increases in metabolic rate during the digestion of a meal as they do while crawling, hence each would have an equal demand for vascular supply when these two actions are combined. To determine, for the Burmese python, whether blood flow is prioritized when snakes are digesting and moving, we examined changes in cardiac performance and blood flow in response to digestion, movement, and the combination of digestion and movement. We used perivascular blood flow probes to measure blood flow through the left carotid artery, dorsal aorta, superior mesenteric artery and hepatic portal vein, and to calculate cardiac output, heart rate and stroke volume. Fasted pythons while crawling experienced a 2.7and 3.3-fold increase, respectively, in heart rate and cardiac output, and a 66% decrease in superior mesenteric flow. During the digestion of a rodent meal equaling in mass to 24.7% of the snake's body mass, heart rate and cardiac output increased by 3.3and 4.4-fold, respectively. Digestion also resulted in respective 11.6and 14.1-fold increases in superior mesenteric and hepatic portal flow. When crawling while digesting, cardiac output and dorsal aorta flow increased by only 21% and 9%, respectively, a modest increase compared with that when they start to crawl on an empty stomach. Crawling did triggered a significant reduction in blood flow to the digesting gut, decreasing superior mesenteric and hepatic portal flow by 81% and 47%, respectively. When faced with the dual demands of digestion and crawling, Burmese pythons prioritize blood flow, apparently diverting visceral supply to the axial muscles. [ABSTRACT FROM AUTHOR]

Objective The goal of this article is to highlight the onset of atheroselerosis in human fetuses of smoker parents and its progression during post-natal life. Methods We examined 46 eases of fetal death (25 males and 21 females) and 43 cases of early neonatal deaths and sudden infant death syndrome (SIDS) (17 males and 26 females) , all died sine causa. All underwent autopsy. 21 eases of 46 fetuses and 21 eases of 43 early neonatal death and SIDS had smoker parents. We examined the four major epicardial coronary arteries , cerebral, common carotids, aorta and the arteries of cords and placenta. All samples were embedded in paraffin and serially cut for histologic examination and immunohistochemical studies (c-Fos,PCNA and apoptosis). Results In 54% of the fetuses and in 63 % of the early neonatal deaths and SIDS structural alterations affecting the arterial wall were evident . In all these eases with atherosclerotie alterations, study of the biological markers showed intense c-Fos positivity of the smooth muscle cells (SMCs). These alterations were constantly observed in the coronary district , mainly in the anterior descending branch, while are less frequent in the other examined arterial district. Very important is also the involvement of fetal adnexa. The immunohistochemical study of the biological markers in the SMCs of atheroselerotic lesions showed intense c-Fos expression in fetuses, and predominant PCNA positivity after birth. Conclusions The birth of atherosclerosis caused by parental smoke and/or air pollution is already detectable in fetal life. It has systemic nature and it is present in different arterial districts. Atherosclerotic lesions are also present in the arteries of medium size. It is also constant the involvement of the arteries of adnexa. In infants, the progression of atheroselerosis determines real atherosclerotic plaques, already recognizable after few weeks of life and closely related to cigarette smoke and formula feeding. During the evolution of the atherosclerotic process a biological modulation of SMCs proliferation is observable, beginning with activation of the c-Fos gene and increasing with high PCNA expressivity. [ABSTRACT FROM AUTHOR]

Our study was developed by using and observing six mammary glands coming from: two cows, two mares and two camels of the Camelus Bactrianus species. The procedure consisted of introducing a tube into the arterial vessels' lumen, through which we then injected a special material, consisting of the industrial product Palux and a red dye. The injected mammary glands were kept in a 2% formaldehyde for 24 hours and then dissected, a process that was done both by direct observance and by using a magnifying glass, to enable a more accurate study of our case. The arterial vascularization in large ruminants is carried out by the external pudendal artery, which branches at the terminal point - in most cases, developing the caudal mammary artery, A. mammaria caudalis, and the cranial mammary artery, A. mammaria cranialis. The caudal mammary arteries participate, after issuing the collaterals responsible for the vascularization of the limphonodes adjacent to the mammals, to the vascularization of the posterior quarters. The cranial mammary artery emits one or two collaterals which ensure the vascularization of the medial gland region, eventually branching into the lateral mammary artery and the medial mammary artery. [ABSTRACT FROM AUTHOR]

Chantler PD, Lakatta EG, Najjar SS. Arterial-ventricular coupling: mech- anistic insights into cardiovascular performance at rest and during exer- cise. J Appi Physiol 105: 1342-1351, 2008. First published July 10, 2008; doi: 10.1 152/japplphysiol.90600.2008.-Understanding the performance of the left ventricle (LV) requires not only examining the properties of the LV itself, but also investigating the modulating effects of the arterial system on left ventricular perfor- mance. The interaction of the LV with the arterial system, termed arterial-ventricular coupling (EAELV), is a central determinant of cardiovascular performance and cardiac energetics. EAELV can be indexed by the ratio of effective arterial elastance (EA; a mEAsure of the net arterial load exerted on the left ventricle) to left ventricular end-systolic elastance (ELV; a load-independent mEAsure of left ventricular chamber performance). At rest, in hEAlthy individuals, EAELV is maintained within a narrow range, which allows the cardiovascular system to optimize energetic efficiency at the expense of mechanical efficacy. During exercise, an acute mismatch between the arterial and ventricular systems occurs, due to a disproportionate incrEAse in ELy (from an average of 4.3 to 13.2, and 4.7 to 15.5 mmHgn ~m2 in men and women, respectively) vs. EA (from an average of 2.3 to 3.2, and 2.3 to 2.9 mmHg mI~ m2 in men and women, respectively), to ensure that sufficient cardiac performance is achieved to meet the incrEAsed energetic requirements of the body. As a result EAELV decrEAses from an average of 0.58 to 0.34, and 0.52 to 0.27 in men and women, respectively. In this review, we provide an overview of the concept of EAELV, and examine the effects of age, hypertension, and hEArt failure on EAELV and its components (EA and ELy) in men and women. We discuss these effects both at rest and during exercise and highlight the mechanistic insights that can be derived from studying EAELV. [ABSTRACT FROM AUTHOR]

Summary: The aim of this research has been to describe the internal pudendal artery distribution in male and female llama and to compare it with that of other domestic animals including the one-humped camel (Camelus dromedarius). The arterial system was perfused with a solution of 14% coloured plaster and preserved in a solution of a 10% formalin, 3% carbolic acid and 3% glycerine. The systematic dissection was made using traditional working techniques and standard instruments. The internal pudendal artery is the ventral terminal branch of the internal iliac artery at the level of the third sacral vertebra. The main supply of the pelvic organs comes from the prostatic or vaginal arteries; notwithstanding these arteries arise from the internal pudendal artery, showing an important difference between ruminants and pig (long iliac type). Similarities between the distribution of the internal pudendal artery of the llama and those obtained in the camel provide strong evidence of a common phylogenetic origin. [Copyright &y& Elsevier]

The dispersion relations, involving attenuation parameters, are given for the lowest modes of propagation in a model of artery consisting of a cylindrical, elastic, thin-walled tube filled with a Newtonian viscous liquid and placed in a medium showing elastic stiffness and internal damping. The amplitudes of the modes generated by the most plausible physiological motions are calculated as functions of the surrounding parameters. Some modes neglected in the existing analyses are shown to be excited with rather high amplitudes that may have important physiological consequences. [ABSTRACT FROM AUTHOR]

Numerous electrical analog models of the circulatory system have been proposed. However, conventional models are either too simple, focusing exclusively on heart function, or overly complex, characterizing arteries in excessive detail. The vessel beds, which comprise arteries, capillaries and veins, are well known to be responsible for most of the pressure drop in blood pressure and to dominate the draining of blood flow. Consequently, electrical analog models of the circulatory system should pay more attention to the vessel beds. This investigation divided the arterial system into several aortic segments with vessel beds, and proposed a model that used electrical lumped elements to represent the vessel beds. The model was adopted to simulate blood pressure propagation by considering each vessel bed as an isolated subsystem. The transfer function between the terminals of isolated subsystems was used to identify the electrical components of the lumped elements that characterized the vessel beds. Simulation results reveal that the compliance and impedance of the vessel beds are larger than in previous models that focused on the aorta or arteries. The proposed electrical lumped model could deal with much more information than the simple models due to the lumped element structure. Furthermore, its isolated subsystem approach also makes the proposed model significantly easier to use than the complex models. [Copyright &y& Elsevier]

Although the primitive vasculature is identical in XX and XY genital ridges until 11.5 days postcoitum (dpc), by 12.5 dpc the XY gonad develops a distinct vasculature. This male-specific vasculature, which includes the development of a large coelomic vessel, develops coincident with expression of Sry and formation of testis cords. We show that similar levels of proliferation and vasculogenesis expand the primary vasculature in XX and XY gonads. However, soon after Sry expression begins, the XY gonad recruits a large number of endothelial cells from the adjacent mesonephros, a mechanism totally absent in XX gonads. These migrating cells do not contribute to venous or lymphatic development. Instead, these cells contribute to the arterial system, as indicated by expression of ephrinB2 and by elements of the Notch signaling pathway. This newly formed arterial system establishes a new pattern of blood flow in the XY gonad, which we speculate may have an important role in export of testosterone to masculinize the XY embryo. [Copyright &y& Elsevier]

Background: It remains to be established to what extent physical activity (PA) levels among individuals are independently associated with deviations from the "optimal" state of the arterial system. Accelerometers have been proposed as means to obtain reliable, objective, and more comprehensive data of PA. Decisions at the time of data collection/processing could influence the association between accelerometry-derived indices and arterial properties., Objectives: (i) To identify to what extent the strength of association between arterial properties and accelerometer-derived indices depend on the recording site and/or the epoch length; (ii) to determine whether some arterial characteristics (hemodynamic vs. structural vs. functional) or regions (elastic vs. transitional vs. muscular arteries; central vs. peripheral) have higher levels of association with accelerometry-derived indices., Methods: Physical activity (PA), cardiovascular risk factors (CRFs), and cardiovascular properties were evaluated in 60 volunteers (general population; age: 23-62 years; women: 43%). PA was measured daily for 7 days (free-living situation; triaxial-accelerometers ActiGraph-GT3X+; hip and wrist; "Worn-to-wrist" option) and raw data was converted at epoch lengths of 1, 5, 10, 30, and 60-s. PA-related energy expenditure, daily time in moderate-to-vigorous PA, steps/minute, and counts-per-minute for vector magnitude were calculated. The cardiovascular evaluation included hemodynamic (central and peripheral pressure), structural (diameters and intima-media thickness), and functional (local and regional stiffness) parameters of carotids, femoral, and brachial arteries, and carotid-femoral and carotid-radial pathways. Arterial z-scores were obtained using age-related equations derived from healthy participants not exposed to CRFs ( n = 1,688; age: 2-84 years; female: 51.2%) to evaluate at which degree each parameter deviates from the "optimal" value., Methods: In general, hip recordings outperformed those obtained on the wrist regarding the strength of association with arterial parameters. Accelerometer-derived indices and their association with arterial properties vary depending on the recording site and epoch length. PA indices are stronger associated with functional (local) than structural variables and with central than peripheral arteries., Conclusions: Regardless of the PA index, there were independent associations with central artery characteristics, which reinforces that these territories would be the most related to PA levels. Differences in data acquisition and processing could lead to differences in conclusions when addressing the association between accelerometer-derived indices and the cardiovascular system., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Gómez-García, Torrado, Bia and Zócalo.)