Search

Deep venous thrombosis is a frequent, multifactorial disease and a leading cause of morbidity and mortality. Most of the time deep venous thrombosis is triggered by the interaction between acquired risk factors, such as hip fracture, pregnancy, and immobility, and hereditary risk factors such as thrombophilias. The mechanisms underlying deep venous thrombosis are not fully elucidated; however, in recent years, important advances have shed light on the role of venous flow, endothelium, platelets, leukocytes, and the interaction between inflammation and hemostasis. It has been described that the alteration of venous blood flow produces endothelial activation, favoring the adhesion of platelets and leukocytes, which, through tissue factor expression and neutrophil extracellular traps formation, contribute to the activation of coagulation, trapping more cells, such as red blood cells. Thus, the concerted interaction of these phenomena allows the formation and growth of the thrombus. In this work, the main mechanisms involved in the pathophysiology of deep vein thrombosis will be described. [ABSTRACT FROM AUTHOR]

Purpose: The objective of this study was to correlate multidetector computed tomography (MDCT) findings in hepatic alveolar echinococcosis (HAE) with intraoperative and postoperative histopathological results to identify reliable MDCT criteria for the diagnosis of HAE venous invasion. Methods: A total of 136 HAE patients who underwent CT examination were included in this study. The lesion-vessel contact angle, irregular wall, lumen stenosis and occlusion were evaluated. Results: A total of 614 veins were estimated. In total, 510 veins were invaded, and 104 veins were not. The invasion rate was 83.06%. In single CT findings, with a cutoff value of > 180° determined by receiver operating characteristic (ROC) curve analysis, the lesion-vessel contact angle performed the best (area under the ROC curve, AUC = 0.907, 95% confidence interval, 95% CI 0.872–0.941, p < 0.001), with a sensitivity, specificity and positive likelihood ratio (PLR) of 84.90%, 88.46%, and 7.35, respectively. Irregular wall and lumen stenosis showed the lowest diagnostic performance. Diagnostic performance was the highest when combining these criteria and signs (AUC = 0.932, 95% CI 0.905–0.960, p < 0.001). Conclusion: The lesion-vessel contact angle > 180° had the best sensitivity and specificity in the diagnosis of HAE venous invasion, and good interobserver agreement had been noted. The diagnostic performance of the lesion-vessel contact angle > 180° had been further improved with the addition of lumen occlusion accompanied by irregular wall or lumen stenosis. [ABSTRACT FROM AUTHOR]

Three-dimensionally printed (3DP) hydrogel-based vascular constructs have been investigated in response to the impaired function of blood vessels or organs by replicating exactly the 3D structural geometry to approach their function. However, they are still challenged by their intrinsic brittleness, which could not sustain the suture piercing and enable the long-term structural and functional stability during the direct contact with blood. Here, we reported the high-fidelity digital light processing (DLP) 3D printing of hydrogel-based vascular constructs from poly(vinyl alcohol)-based inks, followed by mechanical strengthening through engineering the nanocrystalline domains and subsequent surface modification. The as-prepared high-precision hydrogel vascular constructs were imparted with highly desirable mechanical robustness, suture tolerance, swelling resistance, antithrombosis, and long-term patency. Notably, the hydrogel-based bionic vein grafts, with precise valve structures, exhibited excellent control over the unidirectional flow and successfully fulfilled the biological functionalities and patency during a 4-week implantation within the deep veins of beagles, thus corroborating the promising potential for treating chronic venous insufficiency.

Electrospinning is used for producing nonwovens for medical polymer-based implants, such as prosthetic valves or covered scaffolds. In this study, nonwovens for prosthetic venous valves are investigated regarding their morphology and mechanics in physiological medium. Spinning molds were developed based on previous venous valve leaflet designs, 3D printed in different sizes and covered with electrospun nonwovens. Samples were stored in a physiological 0.9% saline at 37°C to investigate the influence of fiber rearrangement and swelling in medium for several weeks. Two different nonwovens of thermoplastic silicone-based polycarbonaturethane (TSPCU) were compared. Tensile test results show that storage in medium has a relevant influence on the mechanical properties. SEM images of TSPCU show substantially increased fiber diameters after 8 days stored in medium. After detaching the valve leaflet nonwovens from the molds, shrinkage of the material of approximately 12% was detected. A suitable valve size could be identified for joining with the stent structure into an interventional prosthetic venous valve. The results demonstrate the influence of storage conditions on the morphological and mechanical properties of electrospun TSPCU nonwovens. For development and dimensioning of venous valve leaflets, this change in mechanical behavior and possible shrinkage of the material has to be considered. [ABSTRACT FROM AUTHOR]

The article presents the discussion on DEGEA Online Seminar for endoscopy personnel together with the Endoscopy Campus sponsored by Chemische Fabrik Dr. Weigert. Topics include focusing on research into the causes of contaminated automated endoscope reprocessors (AERs) and endoscopes; and using disposable valves and an increase in the peracetic acid concentration in the precleaning solution for overcoming the problem.

Copyright of Journal of Surgery & Medicine (JOSAM) is the property of Journal of Surgery & Medicine and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective: To test the therapeutic effect of integrated traditional Chinese and western medicine on venous ulcer of lower limbs by Meta analysis method, and then to propose the best clinical treatment scheme. Methods: Domestic databases in the past 20 years (January 1999-December 2019) were searched by computer, including China Journal Full-text Database (CNKI), VIP, Wanfang and CBM. Literature was screened according to inclusion and exclusion criteria. Cochrane risk assessment tool was used to evaluate the quality of the included literature. Two-classification method was used to extract data. RevMan 5.3 software was used to make statistical analysis of the data. Results: Eleven articles were finally included, totaling 1,576 patients, 804 cases in the treatment group and 772 cases in the control group. Meta-analysis results show that there is no difference in heterogeneity and bias among the included literatures. The total effective rate (risk ratio [RR]=1.12, 95% confidence interval [CI]=1.09-1.15) of integrated traditional Chinese and western medicine in treating venous ulcer of lower limbs is higher, which is obviously better than that of western medicine alone. Conclusion: Through data analysis, it is concluded that in the study population, the treatment of integrated traditional Chinese and western medicine has a significant effect on venous ulcer of lower limbs. Make up for the deficiency of simple western medicine treatment, improve the cure rate and reduce the recurrence rate. However, there is currently a lack of relevant high-quality literature, so a large sample size, rigorous and standardized experimental design and randomized double-blind clinical study are needed to further test the conclusions. [ABSTRACT FROM AUTHOR]

It is widely accepted that the internal mammary vein (IMV) is valveless. However, few anatomical studies are available on the presence or absence of IMV valves. To test the hypothesis that the IMV is valveless, we performed microscopic histological examination of the IMV. IMV samples were collected from 10 human fresh frozen cadavers. For a control, the small saphenous vein (SSV) was obtained. Histological stains were performed. Microscopic examination showed that a venous valve was found in 8 of 20 IMVs. The structure of the valve leaflet consisted of two parts. There was a "thick part" located near the wall of the vein that consisted of smooth muscle cells and fibers. There was also a "thin part" located near the center of the venous lumen that lacked smooth muscle cells. The size of the thick part of the IMV valve was smaller than the SSV valve, whereas there was no difference in the size of the thin part between the IMV and SSV. IMV valves exist. Our results that an IMV valve was present in less than half of IMVs and there was a small-sized valve leaflet suggest that the IMV valve may be rudimentary. [ABSTRACT FROM AUTHOR]

Ultrasound imaging is being used increasingly to aid in the teaching of human physiology and anatomy. Here we describe how its use can be integrated into the teaching of concepts surrounding venous circulation, specifically 1) venous valves and the muscle pump, 2) the effects of hydrostatic pressure on venous pressure, and 3) central venous pressure. The imaging procedures described are relatively simple but add a dimension that helps deliver the teaching points clearly and is enjoyable for students. They also aid in the link of basic physiology to clinical aspects of venous circulatory physiology. [ABSTRACT FROM AUTHOR]

Blood flow in large veins is dependent on arterial-atrial pressure gradients and pumping mechanisms in concert with valve recruitment. Classic descriptions of muscle and respiratory pumps describe venous transmural pressure changes that cause flow. Not often considered is the transmission of pulsatile energy from arteries to veins directly adjacent to each other. Recently, an ex vivo study demonstrated a novel arterial pump effect in venoarterial bundles when valves were active in managing venous flow. We sought to show in vivo evidence of this arterial pump mechanism in 16 healthy young adults. Venous blood flow was measured in the venoarterial bundled deep femoral vein (DFV) and the greater saphenous vein (GSV), which is not bundled with an artery. Veins were studied through randomized body positions of -6° head-down tilt (HDT), supine, 20° head-up tilt (HUT), and 40° HUT, with the assumption that greater HUT postures increased valve dependence to observe the arterial pump effect. Between 20° and 40° HUT conditions, bundled DFV blood flow did not change (68 ± 36 vs. 71 ± 56 mL·min -1 ; P adj > 0.99), whereas nonbundled GSV blood flow decreased (6.1 ± 4.8 vs. 3.5 ± 3.9 mL·min -1 ; P = 0.01). Diameters between 20° and 40° HUT conditions increased in DFV (0.90 ± 0.16 vs. 1.04 ± 0.19 cm; P < 0.01), but not in GSV (0.33 ± 0.10 vs. 0.32 ± 0.08 cm; P = 0.60). These data support previous ex vivo observations that when venous pressure gradients rely on valve recruitment, presence of an adjacent artery may protect against further decreases in blood flow. The arterial pump mechanism is an underappreciated contributor to venous return and warrants further investigation. NEW & NOTEWORTHY Venous return mechanisms have classically considered muscle and respiratory pumps; however, recent ex vivo evidence suggests that pulsatile energy imparted from arteries to adjacent bundled veins can increase venous flow under certain driving pressures. We tested this concept in humans by manipulating hydrostatic pressures and measuring flow in bundled and nonbundled veins. The bundled vein exhibited flow preservation at the highest hydrostatic pressure. We suggest a novel conservation of energy mechanism within the circulatory system.

Background: Treatment for venous malformations of the head and neck includes sclerotherapy, surgical resection, or a combination of both. Surgical resection can remove or reduce the volume of vascular lesions; however, surgery can cause postoperative scarring and potential surgical complications. This study sought to determine the effectiveness of surgery for the treatment of venous malformations of the head and neck. Methods: A retrospective review of the medical records of patients who received surgeries for venous malformations of the head and neck from January 2011 to July 2019 was performed. Using clinical photographs, preoperative and postoperative Doppler ultrasonography, outpatient clinic records, and operation records, the postoperative result and complications were evaluated for each case. Results: Among patients who visited our vascular anomalies clinic, 43 patients (ratio of male to female= 24:19) received surgeries for venous malformations of the head and neck. Twenty-nine patients had undergone surgery only, five patients received sclerotherapy after surgery, and nine patients received surgery after preoperative sclerotherapy. In postoperative evaluations, the result was excellent in 24 patients, good in 18 patients, and poor in one patient. Four patients experienced a recurrence of lesions with lagophthalmos, drooping of the corner of the mouth, partial wound necrosis, and scar widening found in one patient each. Conclusion: Because the head and neck region is the most exposed area in the body, more active implementation of surgical treatments with or without sclerotherapy is essential to reduce the functional and cosmetic impairments associated with venous malformations. [ABSTRACT FROM AUTHOR]

An understanding of the complexity of the cardiovascular system is incomplete without a knowledge of the venous system. It is important for students to understand that, in a closed system, like the circulatory system, changes to the venous side of the circulation have a knock-on effect on heart function and the arterial system and vice versa. Veins are capacitance vessels feeding blood to the right side of the heart. Changes in venous compliance have large effects on the volume of blood entering the heart and hence cardiac output by the Frank-Starling Law. In healthy steady-state conditions, venous return has to equal cardiac output, i.e., the heart cannot pump more blood than is delivered to it. A sound understanding of the venous system is essential in understanding how changes in cardiac output occur with changes in right atrial pressure or central venous pressure, and the effect these changes have on arterial blood pressure regulation. The aim of this paper is to detail simple hands-on physiological assessments that can be easily undertaken in the practical laboratory setting and that illustrate some key functions of veins. Specifically, we illustrate that venous valves prevent the backflow of blood, that venous blood pressure increases from the heart to the feet, that the skeletal muscle pump facilitates venous return, and we investigate the physiological and clinical significance of central venous pressure and how it may be assessed. [ABSTRACT FROM AUTHOR]

The present study aimed to understand the effect of venous valve lesion on the valve cycle. A modified immersed finite element method was used to model the blood–tissue interactions in the pathological vein. The contact process between leaflets or between leaflet and sinus was evaluated using an adhesive contact method. The venous valve modeling was validated by comparing the results of the healthy valve with those of experiments and other simulations. Four valve lesions induced by the abnormal elasticity variation were considered for the unhealthy valve: fibrosis, atrophy, incomplete fibrosis, and incomplete atrophy. The opening orifice area was inversely proportional to the structural stiffness of the valve, while the transvalvular flow velocity was proportional to the structural stiffness of the valve. The stiffening of the fibrotic leaflet led to a decrease in the orifice area and a stronger jet. The leaflet and blood wall shear stress (WSS) in fibrosis was the highest. The softening of the atrophic leaflet resulted in overly soft behavior. The venous incompetence and reflux were observed in atrophy. Also, the atrophic leaflet in incomplete atrophy exhibited weak resistance to the hemodynamic action, and the valve was reluctant to be closed owing to the large rotation of the healthy leaflet. Low blood WSS and maximum leaflet WSS existed in all the cases. A less biologically favorable condition was found especially in the fibrotic leaflet, involving a higher mechanical cost. This study provided an insight into the venous valve lesion, which might help understand the valve mechanism of the diseased vein. These findings will be more useful when the biology is also understood. Thus, more biological studies are needed. [ABSTRACT FROM AUTHOR]

Thrombus is an extremely dangerous factor in the human body that can block the blood vessel. Once thrombosis happens in venous of lower limbs, local blood flow is impeded. This leads to venous thromboembolism (VTE) and even pulmonary embolism. In recent years, venous thromboembolism has frequently occurred in a variety of people, and there is no effective treatment for patients with different venous structures. For the patients with venous isomer with single valve structure, we establish a coupled computational model to simulate the process of thrombolysis with multi-dose treatment schemes by considering the blood as non-Newtonian fluid. Then, the corresponding in vitro experimental platform is built to verify the performance of the developed mathematical model. At last, the effects of different fluid models, valve structures and drug doses on thrombolysis are comprehensively studied through numerical and experimental observations. Comparing with the experimental results, the relative error of blood boosting index (BBI) obtained from non-Newtonian fluid model is 11% smaller than Newtonian fluid. In addition, the BBI from venous isomer is 1300% times stronger than patient with normal venous valve while the valve displacement is 500% times smaller. As consequence, low eddy current and strong molecular diffusion near the thrombus in case of isomer promote thrombolysis rate up to 18%. Furthermore, the 80 μM dosage of thrombolytic drugs gets the maximum thrombus dissolution rate 18% while the scheme of 50 μM doses obtains a thrombolysis rate of 14% in case of venous isomer. Under the two administration schemes for isomer patients, the rates from experiments are around 19.1% and 14.9%, respectively. It suggests that the proposed computational model and the designed experiment platform can potentially help different patients with venous thromboembolism to carry out clinical medication prediction., (© 2023 John Wiley & Sons Ltd.)

Chronic venous disease is caused by chronic venous insufficiency (CVI), which results in significant symptoms such as venous ulcers, ankle eczema, leg swelling, etc. Venous valve incompetence is a major cause of CVI. When the valves of veins in the leg become incompetent (i.e., do not close properly), blood is able to flow backwards (i.e., reflux), which results in blood pooling in the lower extremities, distal venous hypertension, and CVI. Current clinical therapies, such as surgical venous valve reconstruction and bioprosthetic venous valve replacement, are highly invasive and only moderately successful. This is due, in part, to the scanty information available about venous valve leaflet structure and mechanical properties. To date, only one previous study by our research group has reported on the mechanical properties of venous valve leaflet tissue, and specifically in the case of jugular vein valves. In this study, we conducted equibiaxial tensile tests on bovine saphenous vein valve leaflet tissues to better understand their nonlinear, anisotropic mechanical behavior. By stretching the valvular tissues to 60% strain in both the circumferential and radial directions, we generated stress-strain curves for proximal (i.e., those closest to the heart) and distal (i.e., those furthest from the heart) valve leaflets. Histology and collagen assays were also conducted to study corresponding leaflet microstructures and the biochemical properties of the tissues. Results showed: (1) saphenous venous valve tissues possessed overall anisotropic properties. The tissues were stiffer in the circumferential direction than in the radial direction (p<0.01), and (2) saphenous venous valve tissues from the proximal end showed nonlinear isotropic mechanical properties, while those from the distal end showed nonlinear anisotropic mechanical properties. (3) Distal saphenous venous valve tissues appeared to be stiffer than proximal ones in the circumferential direction, p=0.04 (i.e., inter-valvular variability), and (4) the collagen concentration showed a decreasing trend from the proximal to the distal end. This study focuses on highly relevant animal (bovine) tissues to develop test protocols, establish biomechanical structure-function correlations, and to provide data critical to the design of clinical prosthetic venous valves. To the best of the author's knowledge, this is the first study reporting the biaxial mechanical properties of saphenous venous valve leaflet tissues and thus contributes toward refining our collective understanding of valvular tissue biomechanics. [ABSTRACT FROM AUTHOR]

Superficial veins of the upper extremity are the primary location for placement of peripheral IV catheters (PIVC). It is believed that a significant portion of PIVCs placed may cross or abut valves and branching veins or occlude a significant portion of the vein, limiting the ability to aspirate blood from the PIVC. Two separate clinical investigations using ultrasound were performed to understand the potential interaction between PIVCs and the vein lumen and the venous valves and branches of the superficial veins of the upper extremity. One study with 35 adult volunteers interrogated 210 vein segments where a PIV would likely be placed. A second pediatric study evaluated 35 vein segments central to indwelling PIVCs. The combined data from the two studies showed that over 80% of adult veins and 85% of pediatric veins can properly accommodate 20-gauge and 22-gauge PIVC, respectively. Venous valves are frequent findings, either immediately peripheral to branching veins or at periodic 5 to 7 cm points. Antegrade blood flow can be restricted by a placed PIVC, while retrograde flow is very likely to be restricted by venous valves. Together, these findings may explain the difficulty in reliable aspiration of blood from PIVC. [ABSTRACT FROM AUTHOR]

Venous valve tissues, though used in vein reconstruction surgeries and bioprosthetic valves with moderate success, have not been extensively studied with respect to their structure. Their inherent anisotropic, non-linear behavior combined with severe diseases which affect veins, such as chronic venous insufficiency, warrant understanding the structure and material behavior of these tissues. Hence, before any bioprosthetic grafts may be used in place of tissues, it is of the utmost importance to understand the mechanical and structural properties of these tissues as this may lead to higher success rates for valve replacement surgeries. The longevity of the bioprosthetics may also increase if the manufactured grafts behave the same as native valves. Building on the scant information about the uniaxial and biaxial mechanical properties of jugular venous valves and wall tissues from previous studies, the current focus of our investigation lies in understanding the material behavior by establishing a phenomenological strain energy-based constitutive relation for the tissues. We used bovine veins to study the behavior of valve leaflet tissue and adjoining wall tissue (from the proximal and distal ends of the veins) under different biaxial testing protocols. We looked at the behavior of numerical partial derivatives of the strain energy to select a suitable functional form for the strain energy for wall and valve tissues. Using this strain energy descriptor, we determined the Cauchy stress and compared it with experimental results under additional sets of displacement-controlled biaxial testing protocols to find material specific model parameters by the Powell's method algorithm. Results show that whereas wall tissue strain energy can be explained using a polynomial non-linear function, the valve tissue, due to higher non-linearities, requires an exponential function. This study may provide useful information for the primary stages of bioprosthetic designs and replacement surgeries and may support future studies investigating structural models. It may also support the study of valvular diseases by providing a way to understand material properties and behavior and to form a continuum model when required for numerical analyses and computational simulations. [ABSTRACT FROM AUTHOR]

Understanding the hemodynamics surrounding the venous valve environment is of a great importance for prosthetic valves design. The present study aims to evaluate the effect of leaflets' stiffening process on the venous valve hemodynamics, valve's failure on the next proximal valve hemodynamics and valve's failure in a secondary daughter vein on the healthy valve hemodynamics in the main vein when both of these valves are distal to a venous junction. Fully coupled, two-way fluid-structure interaction computational models were developed and employed. The sinus pocket region experiences the lowest fluid shear stress, and the base region of the sinus side of the leaflet experiences the highest tissue stress. The leaflets' stiffening increases the tissue stress the valve is experiencing in a very low fluid shear region. A similar effect occurs with the proximal healthy valve as a consequence of the distal valve's failure and with the mother vein valve as a consequence of daughter vein valve's failure. Understanding the described mechanisms may be helpful for elucidating the venous valve stiffness-function relationship in nature, the reasons for a retrograde development of reflux and the relationship between venous valves located near venous junctions, and for designing better prosthetic valves and for improving their positioning. [ABSTRACT FROM AUTHOR]

The venous bubble load in the body after diving may be used to infer risk of decompression sickness (DCS). Retrospective analysis of post-dive bubbling and DCS was made on seven studies. Each of these investigated interventions, using an 18 meters of sea water (msw) air dive profile from Royal Navy Table 11 (Mod Air Table), equivalent to the Norwegian Air tables. A recent neurological DCS case suggested this table was not safe as thought. Two-hundred and twenty (220) man-dives were completed on this profile. Bubble measurements were made following 219 man-dives, using Doppler or 2D ultrasound measurements made on the Kisman-Masurel and Eftedal-Brubakk scales, respectively. The overall median grade was KM/EB 0.5 and the overall median maximum grade was KM/EB 2. Two cases of transient shoulder discomfort ("niggles") were observed (0.9% (95% CL 0.1% - 3.3%)) and were treated with surface oxygen. One dive, for which no bubble measurements were made, resulted in a neurological DCS treated with hyperbaric oxygen. The DCS risk of this profile is below that predicted by models, and comparison of the cumulative incidence of DCS of these data to the large dataset compiled by DCIEM [1, 2], show that the incidence is lower than might be expected. [ABSTRACT FROM AUTHOR]

Purpose: Cadaveric studies have previously documented a typical pattern of venous drainage within vertebral bodies (VBs), comprised primarily of the basivertebral vein. These studies, however, are limited by the number of samples available. MRI is able to provide 3D images of soft tissue structures in the spine, including the basivertebral vein without the use of contrast in both healthy controls and subjects with abnormal anatomy such as adolescent idiopathic scoliosis (AIS). This study aimed to quantify the venous networks within VBs of 15 healthy adolescent controls and 15 AIS patients. Methods: Five transverse slices through the VBs were examined simultaneously and the observable vascular network traced. The length of the network on the left and right sides of the VB was calculated, and the spatial patterning assessed level-by-level within each subject. Results: Significant differences were seen in the left/right distribution of vessels in both the control and AIS subjects, with both groups having greater length on the right side of all of their VBs. No difference was seen between AIS and control subjects in any region. Large individual variations in patterns were seen in both groups; however, the control group showed more consistent spatial patterning of the vascular networks across levels in comparison to the AIS group. Conclusion: The length of the basivertebral vein was seen to have a significant bias to the right hand side of the VB in both healthy and AIS adolescents. The spatial pattern of this vein showed large variations in branching both within and across individuals. No significant differences were seen between AIS and control subjects, suggesting both that this network is preserved in deformed AIS vertebrae, and that the vertebral venous system does not play a role in the etiology of AIS. [ABSTRACT FROM AUTHOR]

Dysfunction of venous valves can lead to hemodynamic disorders causing venous stasis, which would favour the occurrence of equine laminitis. However, very few studies have investigated venous valves in the horse digit. The purpose of this study was to compare valvular density between thoracic and pelvic limbs and to study the relationship between valvular density of veins and their location, diameter and wall thickness. After dissection, valvular density was calculated based on the number of valves counted in the principal veins of 7 thoracic and 7 pelvic limbs from 7 horses. Our results showed that the valvular density was higher in thoracic limbs, which probably reflects the adaptation to the consequences of hydrostatic pressure. The superficial veins have a higher valvular density that would prevent the varicose risk in the horse. The lower valvular density in the thick veins can be explained by the high density of the smooth muscular cells contained, which would cause an important vasoconstriction via the sympathetic nervous system. The veins with a large diameter also have a lower valvular density; these veins are not exposed to important changes in hydrostatic pressure. Other valvular characteristics may also be involved in the vascular disorders that may be related to the pathophysiology of laminitis. [ABSTRACT FROM AUTHOR]

Introduction: Chronic insufficiency of lower extremity venous valves represents a frequent structural disorder of the vascular system being responsible for a substantial global disease load. While in the field of superficial valve insufficiency surgical as well as endoluminal interventions represent good therapeutic options with high rates of complete remission of symptoms, only limited options exist in the field of deep venous reflux today. Bioengineered, autologous cell-based, endothelialized valve constructs may open up new therapeutic options in these patients, potentially offering novel treatment options in cases with severe insufficiency of deep venous segments in the future. Areas covered: This review summarizes previous reports focusing on venous valve replacement and bioengineering, also including first preclinicalin vivostudies and first clinical trials in patients. In particular, the aspects of current technical and medical limitations of venous valve bioengineering approaches preventing clinical translation and potential solutions by upcoming technologies will be discussed as part of this review. Expert commentary: Bioengineered replacement valves may open up novel options in the treatment of venous valve disease in defined patient groups in the future. However, preventing thromboembolic complications will remain the bottle-neck for clinical translation of the technologies involved. [ABSTRACT FROM PUBLISHER]