Slow Blood Flow Research Articles

Revisiting Virchow’s triad: exploring the cellular and molecular alterations in cerebral venous congestion

BackgroundCerebral venous thrombosis (CVT) is a rare but serious condition that can lead to significant morbidity and mortality. Virchow’s triad elucidates the role of blood hypercoagulability, blood flow dynamics, and endothelial damage in the pathogenesis of CVT. Cerebral venous congestion (CVC) increases the risk of cerebral venous sinus thrombosis and can lead to recurrent episodes and residual symptoms. However, the precise mechanism by which blood congestion leads to thrombosis remains unclear. Our objective was to investigate the cellular and molecular alterations linked to CVC through analysis of the pathological morphology of venous sinus endothelial cells and transcriptomic profiling.ResultsThis study demonstrated a remarkable correlation between CVC and the phenotypic transformation of endothelial cells from an anticoagulant to a procoagulant state. The findings revealed that cerebral venous stasis results in tortuous dilatation of the venous sinuses, with slow blood flow and elevated pressure in the sinuses and damaged endothelial cells of the retroglenoid and internal jugular vein ligation (JVL) rat model. Mechanistically, analysis of transcriptomic results of cerebral venous sinus endothelial cells showed significant activation of platelet activation, complement and coagulation cascades pathway in the JVL rats. Furthermore, the expression of von Willebrand factor (vWF) and coagulation factor VIII (F8) in the complement and coagulation cascades and Fgg and F2 in the platelet activation was increased in the cerebral venous sinuses of JVL rats than in sham rats, suggesting that endothelial cell injury in the venous sinus induced by CVC has a prothrombotic effect. In addition, endothelial cell damage accelerates coagulation and promotes platelet activation. Significantly, the concentrations of vWF, F2 and F8 in venous sinus blood of patients with internal jugular vein stenosis were higher than in their peripheral blood.ConclusionCollectively, our data suggest that CVC can induce endothelial cell damage, which then exhibits a procoagulant phenotype and ultimately increases the risk of CVT. This research contributes to our understanding of the pathophysiology of CVC associated with procoagulant factors and reexamines the components of Virchow’s triad in the context of CVC.

Improved diagnostic confidence using Super Resolution CEUS imaging in testicular lesions.

Ultrasound is the most used interdisciplinary non-ionizing imaging technique in clinical pathologies of the testis. The testis may be affected by a plethora of different disorders such as vasculopathies, trauma, infections and manifestations of primary and secondary malignant masses. Conventional ultrasound represents the basic imaging modality of choice to assess scrotal disorders. Contrast-enhanced ultrasound (CEUS) can provide further information to distinguish between benign and malignant testicular mass lesions. The recent introduction of Super Resolution CEUS Micro-Vascular Imaging (MVI SR) and Time of Arrival (TOA SR) parametric mapping compliments the information provided by conventional CEUS, since these two new post-processing techniques improve the visualization of microvascular structures with slow blood flow and provide high-resolution images of the peak contrast enhancement and temporal perfusion patterns. This paper gives a comprehensive overview of differential diagnoses of the testicular disorder and their corresponding sono-morphologic correlates based on representative cases of the Interdisciplinary Ultrasound Center of the University Hospital Munich.

Full-field amplitude speckle decorrelation angiography.

We propose a new simple and cost-effective optical imaging technique, full-field amplitude speckle decorrelation angiography (FASDA), capable of visualizing skin microvasculature with high resolution, and sensitive to small, superficial vessels with slow blood flow and larger, deeper vessels with faster blood flow. FASDA makes use of a laser source with limited temporal coherence, can be implemented with cameras with conventional frame rates, and does not require raster scanning. The proposed imaging technique is based on the simultaneous evaluation of two metrics: the blood flow index, a contrast-based metric used in laser speckle contrast imaging, and the adaptive speckle decorrelation index (ASDI), a new metric that we defined based on the second-order autocorrelation function that considers the limited speckle modulation that occurs in partially-coherent imaging. We demonstrate excellent delineation of small, superficial vessels with slow blood flow in skin nevi using ASDI and larger, deeper vessels with faster blood flow using BFI, providing a powerful new tool for the imaging of microvasculature with significantly lower hardware complexity and cost than other optical imaging techniques.

Radiomics prediction models of left atrial appendage hypercoagulability based on machine learning algorithms: an exploration about cardiac computed tomography angiography imaging.

Transesophageal echocardiography (TEE) is the standard method for diagnosing left atrial appendage (LAA) hypercoagulability in patients with atrial fibrillation (AF), which means LAA thrombus/sludge, dense spontaneous echo contrast and slow LAA blood flow velocity (< 0.25m/s). Based on machine learning algorithms, cardiac computed tomography angiography (CCTA) radiomics features were adopted to construct prediction models and explore a suitable approach for diagnosing LAA hypercoagulability and adjusting anticoagulation. This study included 652 patients with non-valvular AF. The univariate analysis were used to select meaningful clinical characteristics to predict LAA hypercoagulability. Then 3D Slicer software was adopted to extract radiomics features from CCTA imaging. The radiomics score was calculated using the least absolute shrinkage and selection operator logistic regression analysis to predict LAA hypercoagulability. We then combined clinical characteristics and radiomics scores to construct a nomogram model. Finally, we got prediction models based on machine learning algorithms and logistic regression separately. The area under the receiver operating characteristic curve of radiomics score was 0.8449 in the training set and 0.7998 in the validation set. The nomogram model had a concordance index of 0.838. The final machine-learning based prediction models had good performances (best f1 score = 0.85). Radiomics features of long maximum diameter and high uniformity of Hounsfield unit in left atrial were significant predictors of the hypercoagulable state in LAA, with better predictive efficacy than clinical characteristics. Our combined models based on machine learning were reliable for hypercoagulable state screening and anticoagulation adjustment.

Optimal hematocrit theory: a review.

In humans and many animals, a trade-off between a sufficiently high concentration of erythrocytes (hematocrit) to bind oxygen and sufficiently low blood viscosity to allow rapid blood flow has been achieved during evolution. The optimal value lies between the extreme cases of pure blood plasma, which cannot practically transport any oxygen, and 100% hematocrit, which would imply very slow blood flow or none at all. As oxygen delivery to tissues is the main task of the cardiovascular system, it is reasonable to expect that maximum oxygen delivery has been achieved during evolution. Optimal hematocrit theory, based on this optimality principle, has been successful in predicting hematocrit values of about 0.3-0.5, which are indeed observed in the systemic circulation of humans and many animal species. Similarly, the theory can explain why a hematocrit higher than normal, ranging from 0.5 to 0.7, can promote better exertional performance. Here, we present a review of theoretical approaches to the calculation of the optimal hematocrit value under different conditions and discuss them in a broad physiological context. Several physiological and medical implications are outlined, for example, in view of blood doping, temperature adaptation, dehydration, and life at high altitudes.

ИНСУЛЬТ МЕНЕН ООРУГАН БЕЙТАПТАРДАГЫ ТЕРЕҢ ТАМЫР ТРОМБОЗУНУН ТОБОКЕЛДИК ФАКТОРЛОРУ ЖАНА БОЖОМОЛДООЛОРУ (ИЛИМИЙ АДАБИЯТТАРДЫ КАРАП ЧЫГУУ)

Currently there is no reliable evaluation system for predicting deep vein thrombosis (DVT) in the hospital after ischemic and even more – hemorrhagic stroke. Objective: to review current literature data on the verification of risk factors for the development of DVT in stroke patients and aggressive and early screening strategies in the early post-stroke period. Three fundamental factors underlie the development of DVT: damage to the venous wall, the tendency of blood to hypercoagulation and slow blood flow. Most of the factors that are more or less associated with the development of thromboembolic events revolve around these 3 elements. Typical factors were older age, female gender, changes in the levels of clinical and laboratory variables such as D-dimer or scores on the Berg equilibrium scale. An effective model of risk stratification for DVT at the hospital level after a stroke would be useful for identifying high-risk patients and for implementing individual preventive strategies, therefore further population studies are needed, including in Kyrgyzstan.

Impact of Intraoperative Hypothermia on Incidence of Infection in Implant-Based Breast Reconstruction in Pakistan

Background: Intraoperative hypothermia, an unintentional drop in core body temperature during surgery, poses a significant risk in implant-based breast reconstruction. This condition can weaken immune function, slow blood flow, and increase the risk of postoperative infections. Objective: To evaluate the impact of intraoperative hypothermia on the incidence of infections in patients undergoing implant-based breast reconstruction in Pakistan. Methods: This retrospective cohort study was conducted at Jinnah Sindh Medical University from January 2023 to November 2023. The study included 195 female breast cancer patients aged 18 and above who underwent implant-based breast reconstruction. Patients with pre-existing infections, concurrent chemotherapy or radiotherapy during the perioperative period, and incomplete medical records were excluded. Detailed patient demographics, surgical specifics, and intraoperative temperature control measures were recorded. Patients were categorized into normothermic (core body temperature ≥ 36°C) and hypothermic (core body temperature &lt;36°C) groups. Infection data post-surgery were collected through clinical assessments, blood tests, and imaging techniques. Data were analyzed using SPSS version 25, with descriptive statistics, chi-square tests for categorical variables, and independent t-tests for continuous variables. A p-value of less than 0.05 was considered statistically significant. Ethical approval was obtained, and informed consent was secured from all participants. Results: The mean age of patients was 45.23±3.45 years in the normothermic group and 46.01±2.89 years in the hypothermic group. The hypothermic group had a slightly higher average BMI (25.1 kg/m²) compared to the normothermic group (24.5 kg/m²). Total infections were observed in 26.3% of the hypothermic group versus 10% in the normothermic group. Superficial infections were reported in 12.6% of hypothermic patients compared to 6% of normothermic patients. Deep infections were more prevalent in the hypothermic group at 13.7%, compared to 4% in the normothermic group. The univariate odds ratio (OR) for intraoperative hypothermia was 3.2 (95% CI: 1.5-6.8) and the multivariate OR was 3.0 (95% CI: 1.3-6.5), both with a p-value of less than 0.01. Conclusion: Intraoperative hypothermia significantly increases the risk of postoperative infections in patients undergoing implant-based breast reconstruction. Effective temperature management strategies, such as preoperative warming and the use of intraoperative warming devices, are crucial to reducing infection rates and improving surgical outcomes

Effects of Hyperbaric Oxygen Therapy Combined with Music Therapy on Brain Function and Mental Health of Patients with Aneurismal Subarachnoid Hemorrhage: A Retrospective Study.

Hyperbaric oxygen therapy (HBOT), which is widely used in clinical practice, is aimed at improving nerve function impairment after brain injury. Meanwhile, the effects of music therapy on brain function are unclear. This retrospective study was conducted to explore the application effect of HBOT combined with music therapy on patients suffering from aneurysmal subarachnoid hemorrhage (aSAH). For this retrospective study, 130 patients with aSAH after HBOT were selected from our hospital from June 2021 to June 2022. The patients were divided into the observation (n = 70) and control (n = 60) groups based on whether they received music therapy. Comparisons were made on general demographic data, blood flow rate in median cerebral artery (MCA), cerebral vasospasm (CVS), National Institutes of Health Stroke Scale (NIHSS), activities of daily living (ADL) score, Self-Rating Depressive Scale (SDS), and Self-Rating Anxiety Scale (SAS) of patients. Baseline data between the two groups showed no statistically significant difference (P > 0.05). After management, patients in the observation group presented significantly lower SAS and SDS scores (P < 0.05), lower blood flow rate in MCA, CVS and NIHSS scores (P < 0.05), and higher ADL scores than the control group (P < 0.05). The combination of HBOT and music therapy can considerably improve cerebral neurological deficits, slow down cerebral arterial blood flow, promote the recovery of postoperative cerebral function in aSAH patients, and improve anxiety and depression and the patients' ADL.

Evaluation of fetal cerebral microvascular status and its relationship with fetal growth and development using microvascular imaging technique

The study conducted retrospective analysis design, aiming to explore the use of Microvascular Imaging Technique (MVFI) to assess fetal cerebral microcirculation and analyze the relationship between Microvascular Index (MVI) and fetal growth and development. 100 pregnant women who met the criteria for fetal growth restriction (FGR) provided in the Expert Consensus on Fetal Growth Restriction (2019 Edition) and underwent routine prenatal examinations at the Obstetrics and Gynecology Department of Peking University Third Hospital from January 2021 to June 2023 were selected as the study subjects. A normal fetus with a fetal weight less than 10 % can be classified as FGR, Pregnant women with fetal umbilical artery (UA) systolic and diastolic (S/D) values ≥3 were included in the observation group, while 200 pregnant women with normal fetuses were selected as the control group during the same period. The fetuses’ change in both groups were measured using color Doppler ultrasound, including bi-parietal diameter (BPD), head circumference (HC), abdominal circumference (AC), and femur length (FL). The cerebral microcirculation of the fetuses in both groups was evaluated using MVFI, and the MVI values were compared. The clinical characteristics of FGR fetuses with umbilical artery S/D ratio ≥ 3 were summarized, and the correlation between fetal cerebral microvascular status and fetal growth and development was analyzed using Pearson correlation analysis. The outcomes told that the BPD, HC, AC, and FL values of the fetuses in the control group were lower the other’s value (P < 0.05), and the MVI and peak systolic velocity of the middle cerebral artery (MCA-PSV) values were also lower in the control group (P < 0.05). Pearson correlation analysis revealed a positive correlation between fetal growth and development and MVI and MCA-PSV values in FGR fetuses. In conclusion, MVFI can monitor and quantitatively analyze fetal intracranial microcirculation, visualize slow blood flow in microvascular structures, and this study provides preliminary evidence of the close relationship between fetal cerebral microcirculation and intrauterine growth and development.

Nailfold Capillaroscopy: A Comprehensive Review on Its Usefulness in Both Clinical Diagnosis and Improving Unhealthy Dietary Lifestyles.

Since the 1970s, the utility of nailfold capillaroscopy (NFC) in diagnosing rheumatological disorders such as systemic sclerosis has been well established. Further studies have also shown that NFC can detect non-rheumatic diseases such as diabetes, glaucoma, dermatitis, and Alzheimer disease. In the past decade, nailfold capillary morphological changes have also been reported as symptoms of unhealthy lifestyle habits such as poor diet, smoking, sleep deprivation, and even psychological stress, all of which contribute to slow blood flow. Therefore, studying the relationships between the morphology of nailfold capillaries and lifestyle habits has a high potential to indicate unhealthy states or even pre-disease conditions. Simple, inexpensive, and non-invasive methods such as NFC are important and useful for routine medical examinations. The present study began with a systematic literature search of the PubMed database followed by a summary of studies reporting the assessment of morphological changes detected by NFC, and a comprehensive review of NFC's utility in clinical diagnosis and improving unhealthy dietary lifestyles. It culminates in a summary of dietary and lifestyle health promotion strategy, assessed based on NFC and other related measurements that indicate healthy microvascular blood flow and endothelial function.

New Insights into Cervicofacial Vascular Anomalies.

Congenital cervicofacial vascular anomalies are extremely rare and present many difficulties in diagnosis and treatment requiring a multidisciplinary approach. Firstly, there is little consensus on this subject among head and neck specialists. There are two main types of vascular anomalies: vascular tumors and vascular malformations. Vascular malformations are also divided into malformations with slow blood flow (veins, lymphatics, capillaries or combined) and malformations with a fast blood flow (arteriovenous malformations and fistula). Vascular tumors like hemangiomas are known for their spontaneous involution with aging, while vascular malformations grow in dimensions with age. It is very important to choose the correct differential diagnosis between cervicofacial hemangiomas and vascular malformations for proper therapy management. Anamnesis and clinical exams help in raising suspicions about the real nature of a cervico-vascular anomaly. Furthermore, imaging brings in-depth details of the anomaly, ranging from ultrasound and contrast CT to MRI scanning and minimally invasive angiography. Angiography with selective embolization is rarely a curative procedure for arteriovenous malformations, being more suitable as a preliminary step before attempted surgical removal. Surgery is clearly necessary when there are aesthetic and functional deficits. Slow-flow vascular malformations present a reduced morbidity, and in cases without involution, the surgical ablation is reserved for the cases with aesthetic dysfunctions or psychological trauma. Lymphatic malformations must undergo surgical ablation when they are associated with mass effects and compression of great vessels or aerial viscera. The prognosis after surgical removal is good, with a low rate of recurrence or morbidity. Fast-flow vascular malformations require a combined approach, with embolization and excision in the next 48 h for safety reasons. Removal may be followed by reconstructive surgery depending on the location and dimensions of the malformation, with a possible secondary recovery of the normal microscopic vessels. Some of the masses may hinder the normal airflow and swallowing. Pathology is the gold standard for confirming the clinical and imaging diagnosis.

Microfluidic System-Based Quantitative Analysis of Platelet Function through Speckle Size Measurement.

Platelets play essential roles in the formation of blood clots by clumping with coagulation factors at the site of vascular injury to stop bleeding; therefore, a reduction in the platelet number or disorder in their function causes bleeding risk. In our research, we developed a method to assess platelet aggregation using an optical approach within a microfluidic chip's channel by evaluating the size of laser speckles. These speckles, associated with slowed blood flow in the microfluidic channel, had a baseline size of 28.54 ± 0.72 µm in whole blood. Removing platelets from the sample led to a notable decrease in speckle size to 27.04 ± 1.23 µm. Moreover, the addition of an ADP-containing agonist, which activates platelets, resulted in an increased speckle size of 32.89 ± 1.69 µm. This finding may provide a simple optical method via microfluidics that could be utilized to assess platelet functionality in diagnosing bleeding disorders and potentially in monitoring therapies that target platelets.

A Method to Assess Granger Causality, Isolation and Autonomy in the Time and Frequency Domains: Theory and Application to Cerebrovascular Variability.

Concepts of Granger causality (GC) and Granger autonomy (GA) are central to assess the dynamics of coupled physiologic processes. While causality measures have been already proposed and applied in time and frequency domains, measures quantifying self-dependencies are still limited to the time-domain formulation and lack of clear spectral representation. We embed into the linear parametric framework for computing GC from a driver X to a target process Y a measure of Granger Isolation (GI) quantifying the part of the dynamics of Y not originating from X, and a new spectral measure of GA assessing frequency-specific patterns of self-dependencies in Y. The measures are illustrated in theoretical simulations and applied to time series of arterial pressure and cerebral blood flow obtained in syncope subjects and healthy controls. Simulations show that GI is complementary to GC but not trivially related to it, while GA reflects the regularity of the internal dynamics of the target process. In the application to cerebrovascular interactions, spectral GA quantified the physiological response to postural stress of slow cerebral blood flow oscillations, while spectral GC and GI detected an altered response to orthostasis in syncope subjects, likely related to impaired cerebral autoregulation. The new spectral measures of GI and GA are useful complements to GC for the analysis of interacting oscillatory processes, and detect pathophysiological responses to postural stress which cannot be traced in the time domain. The thorough assessment of causality, isolation and autonomy opens new perspectives for the analysis of coupled processes in both physiological and clinical investigations.

In vivo pilot study into superficial microcirculatory characteristics of colorectal adenomas using novel high-resolution magnifying endoscopy with blue laser imaging

BACKGROUND No studies have yet been conducted on changes in microcirculatory hemodynamics of colorectal adenomas in vivo under endoscopy. The microcirculation of the colorectal adenoma could be observed in vivo by a novel high-resolution magnification endoscopy with blue laser imaging (BLI), thus providing a new insight into the microcirculation of early colon tumors. AIM To observe the superficial microcirculation of colorectal adenomas using the novel magnifying colonoscope with BLI and quantitatively analyzed the changes in hemodynamic parameters. METHODS From October 2019 to January 2020, 11 patients were screened for colon adenomas with the novel high-resolution magnification endoscope with BLI. Video images were recorded and processed with Adobe Premiere, Adobe Photoshop and Image-pro Plus software. Four microcirculation parameters: Microcirculation vessel density (MVD), mean vessel width (MVW) with width standard deviation (WSD), and blood flow velocity (BFV), were calculated for adenomas and the surrounding normal mucosa. RESULTS A total of 16 adenomas were identified. Compared with the normal surrounding mucosa, the superficial vessel density in the adenomas was decreased (MVD: 0.95 ± 0.18 vs 1.17 ± 0.28 μm/μm2, P &lt; 0.05). MVW (5.11 ± 1.19 vs 4.16 ± 0.76 μm, P &lt; 0.05) and WSD (11.94 ± 3.44 vs 9.04 ± 3.74, P &lt; 0.05) were both increased. BFV slowed in the adenomas (709.74 ± 213.28 vs 1256.51 ± 383.31 μm/s, P &lt; 0.05). CONCLUSION The novel high-resolution magnification endoscope with BLI can be used for in vivo study of adenoma superficial microcirculation. Superficial vessel density was decreased, more irregular, with slower blood flow.

147 Medial Septal Nucleus Theta Stimulation Improves Spatial Working Memory and Increases Hippocampal Neurovascular Activity in a Mouse Model of Alzheimers Disease (5xFAD)

INTRODUCTION: Alzheimer’s disease (AD) remains among the most prolific neurodegenerative disorders. The pathogenesis is the result, in part, of aberrant cerebral circuitry; in particular, the mesolimbic-septohippocampal circuit and its associated medial septal nucleus (MSN). Interestingly, the administration of theta stimulation via deep brain stimulation (DBS) to the MSN has been demonstrated to increase hippocampal theta oscillations, which are critical to the role of the hippocampus in learning and memory. Recently, functional ultrasound imaging (fUSI) has emerged as a method of evaluating large-scale neural activity with both high spatiotemporal resolution (∼100 μm3) and sensitivity to slow blood flow (∼1 mm/s). fUSI allows for the in-vivo analyses of neurovascular changes secondary to our theta-burst neuromodulatory intervention. METHODS: 12 male 5xFAD mice were partitioned into two groups, one received theta-burst stimulation targeting the MSN (n = 4) and the other acted as controls (n = 8). Following stimulation, spatial working memory was assessed via the Barnes maze task. An additional 44 C57BL/6 mice were partitioned into three groups: one receiving theta (7.7 Hz) stimulation to the MSN (n = 16), one receiving gamma stimulation to the MSN (100 Hz, n = 14), and the remaining group acting as the control (n = 14). RESULTS: The MSN theta stimulation group of 5xFAD mice demonstrated decreased latency compared to controls (p = 0.003). CBF volumes in the hippocampus were relatively increased in the theta-burst group when compared to both control and gamma stimulation groups. CONCLUSIONS: Our results demonstrate significant improvement in cognitive performance secondary to MSN theta-burst stimulation. Additionally, these changes were mirrored by CBF volume increases in the hippocampus in a frequency-dependent manner. These findings provide evidence for the therapeutic role of theta MSN stimulation in the treatment of AD and furthers fUSI’s role in evaluating in-vivo CBF.

Patient-specific left atrium contraction quantification associated with atrial fibrillation: A region-based approach

Background and objectivesAtrial fibrillation (AF) is a widespread cardiac arrhythmia that significantly impacts heart function. AF disrupts atrial mechanical contraction, leading to irregular, uncoordinated, and slow blood flow inside the atria which favors the formation of clots, primarily within the left atrium (LA). A standardized region-based analysis of the LA is missing, and there is not even any consensus about how to define the LA regions. In this study we propose an automatic approach for regionalizing the LA into segments to provide a comprehensive 3D region-based LA contraction assessment. LA global and regional contraction were quantified in control subjects and in AF patients to describe mechanical abnormalities associated with AF. MethodsThe proposed automatic approach for LA regionalization was tested in thirteen control subjects and seventeen AF patients. After dividing LA into standard regions, we evaluated the global and regional mechanical function by measuring LA contraction parameters, such as regional volume, global and regional strains, regional wall motion and regional shortening fraction. ResultsLA regionalization was successful in all study subjects. In the AF group compared with control subjects, results showed: a global impairment of LA contraction which appeared more pronounced along radial and circumferential direction; a regional impairment of radial strain which was more pronounced in septal, inferior, and lateral regions suggesting a greater reduction in mechanical efficiency in these regions in comparison to the posterior and anterior ones. ConclusionAn automatic approach for LA regionalization was proposed. The regionalization method was proved to be robust with several LA anatomical variations and able to characterize contraction changes associated with AF.

A Case Report of Modified Pancreatic Transplantation With a Limited Splenic Arteriovenous Fistula to Elude Thrombosis

In classic pancreatic transplantation, the splenic artery and vein are ligated at the tail of the pancreas graft. This leads to slowed blood flow in the splenic vein and may cause thrombosis and graft loss. In this study, a patient received a pancreas after kidney transplantation. A modified surgical technique was used in the pancreatic graft preparation. The donor splenic artery and vein were anastomosed end to end at the tail of the pancreas. The splenic artery near the anastomosis was partially ligated, and an effective diameter of 2 mm was reserved to limit arterial blood pressure and flow. The patient recovered very well. Contrasted computed tomography scans on days 11 and 88 after pancreas transplantation indicated sufficient backflow of the splenic vein. We believe that this procedure may avoid the risk of splenic vein thrombosis after pancreas transplantation. This modified technique has not been reported in clinical cases previously and may help reduce the risk of thrombosis after pancreas transplantation.

A modern approach to the study of the problem of pathogenesis and prevention venous thromboembolic complications in patients with trauma (literature review)

Relevance. Patients with trauma are at increased risk of venous thromboembolic complications (VTE), which includes deep vein thrombosis of the lower extremities (DVT) and pulmonary embolism (PE). Within surgical and trauma clinics, thromboembolic complications are the most common preventable cause of in-hospital mortality. Numerous studies have shown that the incidence rate of deep vein thrombosis (DVT) in trauma patients without prevention varies from 5 to 80%.Aim. To analyze the pathogenesis of the development of venous thrombosis and explore existing approaches to prevent VTE in trauma patients.Materials and methods. In the course of the work, topical literary sources of domestic and foreign authors on a given topic were analyzed.Results. The mechanism of thrombus formation in trauma involves slowing blood flow, damage to the vessel wall and impaired blood clotting in the form of hypercoagulation. The state of hypercoagulation combined with prolonged immobility increases the risk of VTE. LMWH is the treatment of choice for the prevention of VTE in trauma. Today, there are ongoing studies related to the correction of preventive doses of LMWH and the search for a single standard, depending on numerous factors.Conclusion. Severity and multiplicity of lesions correlate with severity of systemic inflammation, hypercoagulation, and incidence of venous thrombosis. However, this correlation has not been sufficiently studied in the scientific literature. The search for specific methods for the prevention of deep vein thrombosis leading to PE is an urgent problem of surgery of injuries both peaceful and wartime.

Comparative characteristics of ophthalmological symptoms of orbitocranial and orbital cavernous venous malformation

BACKGROUND: Cavernous venous malformation of the orbit, formerly known as cavernous hemangioma of the orbit, refers to vascular malformations with slow blood flow, and is a frequent lesion of the orbit in adults. The spread of cavernous venous malformation of the orbit into the cranial cavity is extremely rare.&#x0D; AIM: The aim of this study is a comparative analysis of ophthalmological manifestations of orbitocranial and orbital cavernous venous malformation.&#x0D; MATERIALS AND METHODS: The analysis was performed on 50 patients operated in N.N. Burdenko National Scientific and Practical Center for Neurosurgery from 2004 till 2023. Two groups of patients with сavernous venous malformation of the orbit were identified: group 1 — with malformation spreading into the cranial cavity, group 2 —with malformation localized in the orbit only.&#x0D; RESULTS: In 29 patients, cavernous venous malformation of the orbit spread into the cranial cavity through superior orbital fissure, inferior orbital fissure, optic canal and/or through combinations thereof; in 21 patients, the malformation was located in the orbit only. Females prevailed in both groups; the average age was 44 years. The first group included patients with the following features: visual impairments were more frequent and more prominent, oculomotor disorders caused mainly by the involvement of oculomotor and abducens nerves; optic nerve atrophy, slight proptosis. The second group was identified by more prominent proptosis, more mild visual impairments, oculomotor disorders caused by the presence of the malformation in the orbit, at the eye fundus, optic nerve head edema prevailed.&#x0D; CONCLUSIONS: Ophthalmic symptoms due to topographic and anatomical variants of a cavernous malformation.

A combined computational and experimental investigation of the filtration function of splenic macrophages in sickle cell disease.

Being the largest lymphatic organ in the body, the spleen also constantly controls the quality of red blood cells (RBCs) in circulation through its two major filtration components, namely interendothelial slits (IES) and red pulp macrophages. In contrast to the extensive studies in understanding the filtration function of IES, fewer works investigate how the splenic macrophages retain the aged and diseased RBCs, i.e., RBCs in sickle cell disease (SCD). Herein, we perform a computational study informed by companion experiments to quantify the dynamics of RBCs captured and retained by the macrophages. We first calibrate the parameters in the computational model based on microfluidic experimental measurements for sickle RBCs under normoxia and hypoxia, as those parameters are not available in the literature. Next, we quantify the impact of key factors expected to dictate the RBC retention by the macrophages in the spleen, namely, blood flow conditions, RBC aggregation, hematocrit, RBC morphology, and oxygen levels. Our simulation results show that hypoxic conditions could enhance the adhesion between the sickle RBCs and macrophages. This, in turn, increases the retention of RBCs by as much as four-fold, which could be a possible cause of RBC congestion in the spleen of patients with SCD. Our study on the impact of RBC aggregation illustrates a 'clustering effect', where multiple RBCs in one aggregate can make contact and adhere to the macrophages, leading to a higher retention rate than that resulting from RBC-macrophage pair interactions. Our simulations of sickle RBCs flowing past macrophages for a range of blood flow velocities indicate that the increased blood velocity could quickly attenuate the function of the red pulp macrophages on detaining aged or diseased RBCs, thereby providing a possible rationale for the slow blood flow in the open circulation of the spleen. Furthermore, we quantify the impact of RBC morphology on their tendency to be retained by the macrophages. We find that the sickle and granular-shaped RBCs are more likely to be filtered by macrophages in the spleen. This finding is consistent with the observation of low percentages of these two forms of sickle RBCs in the blood smear of SCD patients. Taken together, our experimental and simulation results aid in our quantitative understanding of the function of splenic macrophages in retaining the diseased RBCs and provide an opportunity to combine such knowledge with the current knowledge of the interaction between IES and traversing RBCs to apprehend the complete filtration function of the spleen in SCD.