Direction Of Blood Flow Research Articles

Novel Method for Fetal and Maternal Heart Rate Measurements Using 2-D Ultrasound Color Doppler Flow Images.

Fetal heart rate (FHR) and maternal heart rate (MHR) are important indicators of fetal well-being during pregnancy. A common method in clinical examination is to estimate the FHR using the Doppler shift of echoes from umbilical artery blood flow based on an ultrasound pulsed-wave (PW) Doppler technique. Similarly, a sampling gate can be located at the maternal blood flow to measure MHR using PW Doppler. Ultrasound color Doppler flow imaging (CDFI) is one of the most commonly used imaging modes for clinical fetal examinations. Color coding is employed to display the blood flow velocity and direction in color grades according to the Doppler shift. Continuous CDF images contain dynamic changes characteristics of the blood flow. The periodic characteristics can be used to obtain heart rate information. Therefore, here we propose a novel method to measure FHR and MHR simultaneously using CDF images. The proposed method calculates the histogram of color similarity of CDF images to initially extract the periodic characteristics of the CDF image sequence. The histogram of color similarity function is then processed by a bandpass filter and autocorrelation operation to reduce noise and enhance periodicity. Finally, peak detection is performed on the processed signal to obtain the period and estimate the heart rate. The proposed method can measure the FHR and MHR in parallel after selecting two regions containing the umbilical artery and maternal blood flow, respectively. Thus, the method has high computational efficiency. The proposed method was evaluated on a Doppler flow phantom and clinical CDF images and then compared with the PW Doppler method. The correlation analysis and Bland-Altman plots reveal that the proposed method agrees well with the PW Doppler. It is a sanity check method for real-time clinical FHR and MHR measurements.

A computational comparison of radiofrequency and pulsed field ablation in terms of lesion morphology in the cardiac chamber

Pulsed Field Ablation (PFA) has been developed over the last years as a novel electrical ablation technique for treating cardiac arrhythmias. It is based on irreversible electroporation which is a non-thermal phenomenon innocuous to the extracellular matrix and, because of that, PFA is considered to be safer than the reference technique, Radiofrequency Ablation (RFA). However, possible differences in lesion morphology between both techniques have been poorly studied. Simulations including electric, thermal and fluid physics were performed in a simplified model of the cardiac chamber which, in essence, consisted of a slab of myocardium with blood in motion on the top. Monopolar and bipolar catheter configurations were studied. Different blood velocities and catheter orientations were assayed. RFA was simulated assuming a conventional temperature-controlled approach. The PFA treatment was assumed to consist in a sequence of 20 biphasic bursts (100 µs duration). Simulations indicate that, for equivalent lesion depths, PFA lesions are wider, larger and more symmetrical than RFA lesions for both catheter configurations. RFA lesions display a great dependence on blood velocity while PFA lesions dependence is negligible on it. For the monopolar configuration, catheter angle with respect to the cardiac surface impacted both ablation techniques but in opposite sense. The orientation of the catheter with respect to blood flow direction only affected RFA lesions. In this study, substantial morphological differences between RFA and PFA lesions were predicted numerically. Negligible dependence of PFA on blood flow velocity and direction is a potential important advantage of this technique over RFA.

Capillary communication: the role of capillaries in sensing the tissue environment, coordinating the microvascular, and controlling blood flow.

Historically, capillaries have been viewed as the microvascular site for flux of nutrients to cells and removal of waste products. Capillaries are the most numerous blood vessel segment within the tissue, whose vascular wall consists of only a single layer of endothelial cells and are situated within microns of each cell of the tissue, all of which optimizes capillaries for the exchange of nutrients between the blood compartment and the interstitial space of tissues. There is, however, a growing body of evidence to support that capillaries play an important role in sensing the tissue environment, coordinating microvascular network responses, and controlling blood flow. Much of our growing understanding of capillaries stems from work in skeletal muscle and more recent work in the brain, where capillaries can be stimulated by products released from cells of the tissue during increased activity and are able to communicate with upstream and downstream vascular segments, enabling capillaries to sense the activity levels of the tissue and send signals to the microvascular network to coordinate the blood flow response. This review will focus on the emerging role that capillaries play in communication between cells of the tissue and the vascular network required to direct blood flow to active cells in skeletal muscle and the brain. We will also highlight the emerging central role that disruptions in capillary communication may play in blood flow dysregulation, pathophysiology, and disease.

Does sympathetic vasoconstriction contribute to metabolism: Perfusion matching in exercising skeletal muscle?

The process of matching skeletal muscle blood flow to metabolism is complex and multi-factorial. In response to exercise, increases in cardiac output, perfusion pressure and local vasodilation facilitate an intensity-dependent increase in muscle blood flow. Concomitantly, sympathetic nerve activity directed to both exercising and non-active muscles increases as a function of exercise intensity. Several studies have reported the presence of tonic sympathetic vasoconstriction in the vasculature of exercising muscle at the onset of exercise that persists through prolonged exercise bouts, though it is blunted in an exercise-intensity dependent manner (functional sympatholysis). The collective evidence has resulted in the current dogma that vasoactive molecules released from skeletal muscle, the vascular endothelium, and possibly red blood cells produce local vasodilation, while sympathetic vasoconstriction restrains vasodilation to direct blood flow to the most metabolically active muscles/fibers. Vascular smooth muscle is assumed to integrate a host of vasoactive signals resulting in a precise matching of muscle blood flow to metabolism. Unfortunately, a critical review of the available literature reveals that published studies have largely focused on bulk blood flow and existing experimental approaches with limited ability to reveal the matching of perfusion with metabolism, particularly between and within muscles. This paper will review our current understanding of the regulation of sympathetic vasoconstriction in contracting skeletal muscle and highlight areas where further investigation is necessary.

Impact of common rhythm disturbances on echocardiographic measurements and interpretation.

Transthoracic echocardiography (TTE) remains the workhorse of noninvasive cardiac imaging, allowing to easily obtain precise information on cardiac structure and function. Over time, Doppler interrogation of blood flow velocities, direction, and timing in several locations within the heart became the primary method for haemodynamic assessment, replacing cardiac catheterization in most clinical settings and providing valuable diagnostic and prognostic information on a wide spectrum of cardiac pathological processes. Abnormalities in heart rate, rhythm, and intracardiac electrical conduction are commonly encountered during the performance of echocardiographic studies. Up to now, only a modest attention has been given to the impact of these abnormalities on the reading and interpretation of echocardiographic examination and this assessment has not yet been carried out in a global and systematic way. Tachyarrhythmias, bradyarrhythmias and atrioventricular conduction disturbances influence cardiac structure and mechanics as well as Doppler flow patterns. For this reason, and to be able to avoid misinterpretation, echocardiographers must be aware of the consequences of these common rhythm disturbances on echocardiographic findings. This narrative review aims to describe the current knowledge on this topic, focusing on the expected mechanical effects and Doppler patterns observed on transthoracic echocardiography in patients with common rhythm (tachycardia and bradycardia, atrial flutter and fibrillation and ectopic beats) and conduction disturbances (namely, atrioventricular block).

Effect of the arterial needle bevel position on puncture pain and postremoval bleeding time in hemodialysis patients: A self-controlled, single-blind study.

This study aimed to investigate the effect of the bevel orientation (facing upwards or downwards towards the skin) of the needle inserted into the arterial limb of the arteriovenous fistula (AVF) on puncture pain and postremoval bleeding time. This study, using a single-blind crossover design, was conducted on 35 maintenance hemodialysis patients who had been dialyzed for at least 6months and in whom blood access was via an AVF. AVF cannulation was performed with the needle bevel pointing upward in the first six sessions and the needle bevel pointing downwards (towards the skin) in the subsequent six sessions. Needles were always inserted in the direction of blood flow. At each dialysis session, cannulation pain was measured using a visual analog scale (VAS), and the bleeding time at the end of dialysis after needle removal was recorded. The VAS score and postremoval bleeding time were lower when the needle bevel pointed downwards towards the skin during insertion (P<0.05). Insertion of the needle with the bevel pointed downward decreased puncture pain during cannulation and bleeding time postdialysis on needle removal.

Cell-To-Cell Communication in the Resistance Vasculature.

The arterial vasculature can be divided into large conduit arteries, intermediate contractile arteries, resistance arteries, arterioles, and capillaries. Resistance arteries and arterioles primarily function to control systemic blood pressure. The resistance arteries are composed of a layer of endothelial cells oriented parallel to the direction of blood flow, which are separated by a matrix layer termed the internal elastic lamina from several layers of smooth muscle cells oriented perpendicular to the direction of blood flow. Cells within the vessel walls communicate in a homocellular and heterocellular fashion to govern luminal diameter, arterial resistance, and blood pressure. At rest, potassium currents govern the basal state of endothelial and smooth muscle cells. Multiple stimuli can elicit rises in intracellular calcium levels in either endothelial cells or smooth muscle cells, sourced from intracellular stores such as the endoplasmic reticulum or the extracellular space. In general, activation of endothelial cells results in the production of a vasodilatory signal, usually in the form of nitric oxide or endothelial-derived hyperpolarization. Conversely, activation of smooth muscle cells results in a vasoconstriction response through smooth muscle cell contraction. © 2022 American Physiological Society. Compr Physiol 12: 1-35, 2022.

Clinicopathologic Findings in Chickens (Gallus gallus domesticus) Administered Amikacin Through Intravenous Regional Limb Perfusion.

Regional limb perfusion (RLP) has been used to treat cases of distal limb infections in avian species. Potentially nephrotoxic drugs, such as amikacin, may increase the risk of nephrotoxicity with RLP because of the presence of the renal portal system and direct venous blood flow from the pelvic limbs to the kidneys. In a randomized, blinded, placebo-controlled study, the safety of repeated amikacin administration (20 mg/kg q24h for 3 doses) via RLP was evaluated in healthy female chickens (Gallus gallus domesticus; n = 8 treatment, n = 8 saline control group). Plasma uric acid concentrations were not significantly elevated in treated birds compared with the control group at any time point following RLP. One week following the final RLP, birds were necropsied and the kidneys evaluated grossly and histologically. There was no significant difference in renal pathology scores between treated and control birds or between kidneys ipsilateral to the perfused limb and contralateral kidneys. This study concludes that RLP of amikacin at high doses produced no discernable renal pathology in healthy euhydrated chickens.

In vivo computation with sensor fusion and search acceleration for smart tumor homing

Background and Objective:Motivated by the advancements on bioresorbable nanoswimmers, this paper considers the advantages of direct targeting over systemic targeting for smart tumor homing under the general framework of computational nanobiosensing. Nanoswimmers assembled by magnetic nanoparticles can be used as contrast agents to estimate the locations of tumors inside the human body. Methods:Closely observing the response of nanoswimmers (which act as in vivo biosensors) to the tumor-triggered biological gradients and then guiding them through external manipulation, can result in a higher accumulation at the diseased location. Sensor informatics along with data fusion can play a crucial role in such a knowledge-aided targeting process. Specifically, built upon our previous work on direct targeting inspired by the gradient descent optimization, this work is focused on resolving the real-life constraints of in vivo natural computation such as uniformity of the magnetic field and finite life span of the nanoswimmers. To overcome these challenges, we propose a multi-estimate-fusion strategy to obtain a common steering direction for the swarm of nanoswimmers. Results:We show through computational experiments (1) that the mean of individual gradient estimations provides the best choice for symmetrical conditions (tumor location in line with the direction of blood flow) while leader-based swarm steering gives the best results for non-symmetrical search space, and (2) that the iterative memory-driven gradient descent optimization detects the target faster compared to the classical memory-less gradient descent and knowledge-less systemic targeting. Conclusion:Our proposed strategies demonstrate that a clear demarcation between malignant tumors and healthy tissues can be visualized before nanoswimmers are consumed in human vasculature. We believe that our work will help in overcoming the challenges posed by natural in vivo computation for tumor diagnosis at its early stage.

Rats caudal vena cava hemodynamics features in different age periods

Introduction. Liver hemodynamics age-related features studying is promising area of portal and caudal vena cava and hepsatic artery of rats hemodynamics exploration.Aim was to determine qualitative and quantitative hemodynamic paremeters of the laboratory rats caudal vena cava of different genders and ages.Materials and methods. The study was conducted on 60 mongrel rats (males and females, 120–170 g) divided into three age groups. The first group included 20 rats aged 1 month, the second – 20 rats aged 6–12 months and the third – 20 rats aged more than 18–24 months. The study of caudal vena cava qualitative and quantitative hemodynamic parameters was performed by ultrasound scanners. Animals were anaesthesized by zoletil-xylazine. Digital data were processed by methods of variational statistics.Results. All animals showed the antegrade caudal vena cava blood flow. The spectrum of blood flow differed in the number, shape of teeth and phase. The most animals showed three-phase spectrum not depend on the animals gender and age. The diameter of the vein did not depend on the gender. In the I and II age groups, the predominance of the volumetric blood flow rate in the CPV in males compared with females was within 10 % (R=0.98 and R=0.37, respectively), in the III age group, the relationship was not statistically significant (R=–0.03). The diameter and maximum systolic blood flow velocity in the caudal vena cava increased slightly (within 3 %) with the age of the animals (R=0.64 and R=0.43, respectively). Volumetric blood flow rate decreased within 4 % with increasing age (R=0.42).Conclusion. The spectrum of rats caudal vena cava blood flow differed in the number, shape of waves and phase. In most animals it was three-phase. In all animals the direction of blood flow was antegrade. The phase of the spectrum was not affected by the animals gender and age. There was no statistically significant dependence of the diameter and linear velocity of blood flow on the gender. The volumetric blood flow rate was slightly higher in males (within 10 %) compared to females. The diameter and the maximum systolic blood flow velocity increased slightly (within 3 %) with the age of the animals. The indicator of the volumetric blood flow rate decreased within 4 % with increasing age.

STUDY ON THE NONLINEAR DEFORMATION MECHANICAL PROPERTIES OF A NEW TYPE OF VENA CAVA FILTER

In order to analyze the mechanical properties of a new type of retrievable vena cava filter, the Denali and Aeginsy retrievable filters are selected, and the in vivo and in vitro mechanical properties of the three types of retrievable vena cava filters are compared. The nonlinear deformation process of the filter which is pressed into the transport sheath, flicked and released into the vascular vessel is simulated by using the finite element method, and the mechanical behaviors of the filter and the blood vessel wall are analyzed. During the crimping process, the elastic strain peak value of the filter wall increases with increasing amount of grip. The maximum elastic strain peak value of the three filters is less than 8%, and the safety factor is greater than 2, which meets the strength requirement. Equivalent stress and strain on the vascular wall decreases along the direction of blood flow after the filter is opened. The peak value of equivalent stress and strain on the vascular wall corresponding to Aegisy filter is the largest, and the impact on the vascular wall is the largest. The total displacement of the three filters under the action of thrombus and blood fluids is not more than 80[Formula: see text][Formula: see text]m. The impact of the new filter on the vascular wall is smaller than that of Aegisy filter, and the total displacement after implantation is smaller than that of Denali filter. The results are valuable for the evaluation and clinical application of the new vena cava filter.

Transfemoral Flow-Reversal for Carotid Artery Stenting with Balloon Guide Catheter: Proof of Concept with Robotic Transcranial Doppler.

In this video, we demonstrate our technique for transfemoral carotid artery stenting (CAS) with flow-reversal through a Walrus balloon guide catheter (BGC) using robotic transcranial Doppler (rTCD) monitoring. Before crossing the plaque for distal filter placement and/or angioplasty, the BGC is inflated and the three-way stopcock opened, allowing back-bleeding. Immediately, the rTCD shows a change in blood-flow direction, indicating flow-reversal, which likely occurs due to a passive pressure gradient between the intracranial compartment and the atmospheric pressure. Then, the filter is placed with reduced risk of displacing plaque fragments, and angioplasty and stenting are performed with dual protection afforded by the BGC and filter. This technique may confer greater safety for CAS. Although in this case rTCD was used for proof of concept, it could also be used as a tool to monitor embolic load during CAS procedures.

Kazakhstan CTO Club's recommended guidelines for interventional therapy for coronary chronic total occlusion

Chronic total occlusion (CTO) disease refers to obstructive coronary artery disease, which is the degree of direct blood flow of the blood flow TIMI 0 degree of occlusion time 3 months, if there are already well-developed collaterals or bridge collaterals, the distance from the occlusion of the blood vessel TIMI blood flow > 0 degree is still considered a total occlusion disease. Previous studies have shown that 20% of patients with coronary heart disease have experienced CTO lesion from at least one vessel, Percutaneous Coronary Intervention (PCI) surgery is called the

Dissection Techniques and Histological Sampling of the Heart in Large Animal Models for Cardiovascular Diseases

The standard gross examination and sampling are key elements in the reproducibility and success of experimental studies of cardiovascular diseases carried out in large animals. Considering the complex anatomy of the heart, interspecies differences, and the types of compensatory and pathological reactions, consistent protocols are challenging to implement. The utilization of multiple dissection protocols is usually adapted to suit the prosector's experience, and personal preference continues to be a source of experimental and interobserver variability. Here, the aim is to present the main anatomical features and landmarks, dissection protocols, and histological sampling standards of the heart in some commonly used species (including dogs, pigs, ruminants, and cats) as models of cardiovascular diseases. Two standard gross examination protocols are presented here. First, the inflow-outflow method, which follows the physiological blood flow direction through the heart and large vessels (frequently used in dogs, ruminants, and pigs), and second, the four-chamber dissection technique (exemplified in cats). Both techniques can be adapted to any species in certain experimental circumstances. The sampling protocols include all the areas of interest (sinoatrial node, ventricles, interventricular septum, atria, valves, and aorta), and if properly carried out, improve both the reproducibility and reliability of experimental studies.

Regional hemodynamics characteristics in patients with non-arteritic anterior ischemic optic neuropathy

BACKGROUND: Non-arteritic anterior ischemic optic neuropathy (NAION) takes the first place in the total amount of acute vascular optic neuropathy cases. There is no common understanding of pathogenetic mechanisms of disease. This is largely due to the absence of direct optic nerve head blood flow registration method in ophthalmology.&#x0D; AIM: The aim of this work is to evaluate ocular hemodynamics using different methods in patients with non-arteritic anterior ischemic optic neuropathy (NAION).&#x0D; MATERIALS AND METHODS: 73 patients were enrolled in the study. 46 patients (46 eyes) with NAION were included in the first group. Control group was composed of 27 patients (50 eyes) with systemic risk factors of NAION without any retinal and optic nerve diseases. Regional hemodynamics parameters were evaluated with ophthalmosphigmography, ophthalmoplethysmography, ophthalmoreography, OCT-angiography and EDI-OCT.&#x0D; RESULTS: Blood flow values in different parts of the choroid did not statistically differ between groups when using ophthalmosphigmography, ophthalmoplethysmography, ophthalmoreography methods. Radial peripapillary capillaries in optic nerve head area were evaluated, and statistically significant difference was found in all sectors.&#x0D; CONCLUSION: The main component of NAION pathogenesis is a decreasing perfusion pressure in paraoptic short posterior ciliary arteries. Blood flow in choroid does not play an important role in the disease pathogenesis.

A novel angiographic classification of pseudoaneurysms of the pulmonary chronic inflammatory cavity based on selective angiograms and therapeutic implications.

BackgroundHemoptysis is a common clinical symptom. In the chronic tuberculosis cavity and chronic necrotizing pneumonia cavity, pseudoaneurysms (Pas) easily form and are prone to massive hemoptysis and repeated hemoptysis and can even endanger patient's life. However, it remains to be further analyzed whether Pas of the pulmonary chronic inflammatory cavity selectively affect the peripheral pulmonary branches. This study is based on selective angiography to classify peripheral pulmonary arterial Pas (PAPs) of the pulmonary chronic inflammatory cavity and to determine treatment options for PAPs, thereby guiding individualized clinical treatment.MethodsAngiographic data of 392 noncancer patients undergoing hemoptysis were retrospectively analyzed. All of the patients underwent pulmonary and selective pulmonary angiography and bronchial and nonbronchial systemic collateral arterial angiography. A total of 9 patients had Pas of the pulmonary chronic inflammatory cavity, and a pseudoaneurysm systemic artery collateral (Pasac), inflow and outflow sections of the parent vessels, and direction of blood flow in the parent vessels were clearly observed with digital subtraction angiography (DSA) and/or C-arm cone-beam flat-panel detector computed tomography angiography (CBCTA). Patients with underlying disease had pulmonary tuberculosis (n=8) or lung abscess (n=1). The angiographic types of Pas were analyzed.ResultsEight patients with chronic pulmonary tuberculosis and 1 patient with a necrotizing pneumonia cavity in the convalescent period were included in the study. Pas of the pulmonary chronic inflammatory cavity presented the following types: (I) pulmonary artery pseudoaneurysm (PAPa) (n=2 cases); (II) body arterial Pa (n=3 cases); and (III) systemic-pulmonary anastomosis Pa. Each type could be divided into two subtypes (n=4 cases). In nine cases, embolization and hemostasis were technically and clinically successful.ConclusionsPas of the pulmonary chronic inflammatory cavity are diverse (especially in cases of pulmonary tuberculosis). Angiographic typing plays a guiding role in the selection of an embolization strategy.

Thermal effects on SARS-CoV-2 transmission in peristaltic blood flow: Mathematical modeling

SARS-CoV-2 is a novel viral species that has been identified as a highly infectious disease. Scientists have endeavored to collect essential information to better characterize the behavior of this virus, including droplet transmission and airborne effects. However, it is not clear, thus far, whether temperature can substantially alter the pandemic trajectory. This present study, therefore, aims to investigate how temperature may affect virus transmission in peristaltic blood vessels and, furthermore, how virus density and particle diameter will affect the transmission of the virus from an infected person to a non-infected person. The modeling deployed assumes that coronavirus particles with a diameter of 120 μm and a density of 1 g/cm3 move in the direction of blood flow. The quantity of SARS-CoV-2 virions (entire virus particles) inside a microdroplet is calculated by considering the Kepler conjecture method, and the transmission percentage of the viral load is also computed. It is observed that the microdroplet carries a smaller amount of coronavirus particles, so an airborne (DP&amp;lt;2 μm) infection is less harmful. Furthermore, computational simulations using the proposed model reveal some interesting insight into how rapidly the SARS-CoV-2 virus propagates in the circulatory system, and estimate the infection in blood and tissues. From these results, it is found that the small virion (dp&amp;lt;100 nm) rapidly settles inside the bloodstream and infects tissues; however, the duration of infection is short due to the low viscosity of the blood. Furthermore, the closed packed structure of the virions is loosened in the blood vessel due to the temperature of the blood.

Quantifying the Cardiovascular Physiology of REBOA and Partial REBOA: How REBOA Facilitates Resuscitation but Also Strains the Left Ventricle

Resuscitative endovascular balloon occlusion of the aorta (REBOA) is increasingly used as an endovascular approach to aortic occlusion. This can provide complete or partial aortic occlusion and is thereby known to augment afterload relative to the extent of occlusion. Despite the increasing use of this tool, little cardiovascular physiology has been quantified across clinically relevant REBOA transitions: placement of occlusive REBOA, then transition to partially occlusive REBOA, and lastly, REBOA removal. The goal of this study is to use pressure-volume loop analysis and direct left coronary artery blood flow measurements to capture these transitions in a swine model of hemorrhagic shock to elucidate the underlying physiologic mechanism of clinical REBOA use. Swine underwent complex surgical and vascular access instrumentation to capture real-time left ventricular pressure-volume loops and directly measure left coronary flow (Figure 1). Animals were hemorrhaged to 45 mmHg with subsequent placement of fully occlusive REBOA, followed by transition to partial REBOA while these data were captured. A full methodological protocol has been published: https://doi.org/10.21203/rs.3.pex-1646/v1. Five male swine underwent this protocol (mean weight, 53.6 ± 3.6 kg). Hemorrhagic shock was induced and maintained with reduction of stroke work (baseline: 3.1 L × mmHg vs shock: 1.2 L × mmHg; P < .01) and average end systolic pressure (109.8 vs 59.6 mmHg; P = .02). REBOA augmented the end systolic pressure volume relationship. Stroke work evolved with placement of occlusive REBOA (1.2 vs 4.3 mmHgL; P < .01). End systolic elastance was augmented from baseline by shock and REBOA placement (1.01 vs 0.39 vs 4.50 mL/mmHg; P < .01) and remained elevated with transition to partial REBOA (3.22 mL/mmHg) (Figure 2). Percent time in antegrade coronary blood flow decreased during shock (94% to 71.8%; P < .01) and was rescued with REBOA, but REBOA also increased peak coronary flow compared with shock (271 vs 93 mL/min; P < .01) and total coronary flow, even beyond baseline (peak: 2136 vs baseline: 424 mL/min; P < .01). No REBOA state augmented the end diastolic pressure volume relationship. REBOA maintains the end diastolic pressure volume relationship, but increases afterload, thereby augmenting the end systolic pressure volume relationship and left ventricle contractility with partial REBOA. REBOA alters coronary artery blood flow by reversing shock-induced retrograde coronary flow, and increasing peak coronary artery flow, therefore increasing total flow. The afterload modulation from REBOA underlies its resuscitative capability but may drive the mechanism of cardiovascular injury. Partial REBOA with resuscitation balances the afterload improvement against undue left ventricle strain.Fig 2End systolic elastance (Ees; the slope of the end systolic pressure volume relationship) evolution across study periods. *P = .003; **P = .048; ***P = .01; ****P = .015.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Evolution of the Flow Patterns After Endovascular Treatment in Patients with High-Grade Carotid Artery Stenosis - the Clinical Value of Insonation of the Supratrochlear Artery and Alternating Flow

AimWe aimed to describe the evolution of flow pattern in the ophthalmic artery (OA) and supratrochlear artery (SA) by transcranial Doppler (TCD) ipsilateral to a severe proximal carotid artery stenosis before and after staged endovascular treatment (EVT). MethodsWe insonated and recorded the flow patterns of OA and SA in 63 patients with ≥ 80% carotid artery stenosis before and after staged carotid angioplasty and stenting at 2-4 weeks apart. Based on the direction of OA and SA blood flow, we categorized patients into (1) reversed, (2) alternating, or (3) forward flow, groups. We evaluated the evolving sonographic flow patterns in OA and SA at the 3-time points and correlated them with the stenotic and flow velocity change. ResultsDespite the disconcordance between OA and SA, the evolution of flow direction were evoluted from reversed to alternating or from alternating to forward in both OA and SA. OA and SA's disagreement rate at three-time points was 19.1%, 49.2%, and 28.6%, respectively. After angioplasty alone, we detected an alternating flow in 21 (33.3%) and 46 (73.0%) patients in OA and SA, respectively. Alternating flow patterns in SA persisted in 20 patients (31.7%) after stenting. The post-angioplasty residual stenosis did not differ between the three flow pattern groups (p>0.05). ConclusionsAn alternating flow in OA or SA might mark the hemodynamic recovery after EVT. Insonation of SA may provide supporting evidence for hemodynamic change in patients with carotid artery stenosis undergoing EVT.

Noninvasive monitoring of intracranial pressure after cardiac surgery: case report

Background: Heart valves are important structures that play an essential role in directing blood flow; changes in the functioning of these structures may require cardiac surgery with cardiopulmonary bypass. The behavior of intracranial pressure (ICP) in patients undergoing this type of surgery is unknown. Objective: aim of this study was to report alterations in the waveform morphology of ICP in a patient submitted to cardiac surgery with cardiopulmonary bypass. Case Description: This report provides data on ICP waveform morphology (P1 and P2 peaks) monitored before, immediately after, and on the 5th day after cardiac surgery. In the preoperative evaluation, the morphology of the patient's ICP waveforms was slightly altered, possibly due to the underlying cardiovascular disease. In the second measurement of the ICP waveforms, performed after surgery, the wave morphology of the ICP was normal. On the 5th PO day, after the patient presented clinical signs of neurological complications, the third ICP measurement was performed, which showed that the morphology of the ICP wave was altered.Conclusions: The use of non-invasive monitoring of ICP is of great importance in patients undergoing cardiac surgery, with the aim of diagnosing, preventing and/or enabling rapid treatment in cases where there is an evolution of more severe neurological complications that may lead to death.