Venous Segments Research Articles

Microcirculatory parameters in compensated and decompensated type 2 diabetes mellitus

To reveal the features of microcirculatory parameters in compensated and decompensated type 2 diabetes mellitus (T2DM). A total of 196 patients with T2DM were examined and divided into 2 groups: 1) 52 patients (40.4% of men) aged 52.8±8.7 years with compensated T2DM (glycated hemoglobin (HbA1с), 6.3±0.5%); 2) 68 patients (38.2% of men) aged 52.8±8.1 years with decompensated T2DM (HbA1с, 9.4±1.7%). Both patient groups had concomitant hypertension (its prevalence, degree, stage of hypertension were comparable). A control group consisted of 76 volunteers (40.8% of men) aged 52.2±8.7 years with normal carbohydrate metabolism and without signs of cardiovascular disease (HbA1с, 5.3±0.49%). Capillary blood flow in the finger nail-fold area was investigated in all the participants. A digital optical capillaroscope with image-processing software was used to obtain quantitative blood microcirculatory parameters. The diameters of arterial and venous capillary segments were measured, by calculating the remodeling rate. The degree of capillary tortuosity, network density, and polymorphism and the size of the perivascular zone (PZ) were estimated. Blood rheological properties and capillary blood flow velocity were also investigated. The decompensated T2DM group compared to the compensated T2DM group was found to have a narrowing of the arterial capillary segment diameter (8.4±2.0 µm; p=0.009) and an increase in remodeling rates (1.47±0.22; p=0.000). The tendency of the PZ size to be larger in patients with decompensated T2DM compared to those with compensated T2DM (p=0.080) and the increase in this indicator compared to the control group (p=0.001) reflect the presence of edema syndrome in Group 2, as laboratory confirmed by a statistically significantly elevated sodium level (p=0.000; p=0.006). The enlarged venous capillary segment demonstrates involvement of the venous component in microcirculatory disorders in T2DM. The reduction in the density of the capillary network and the increase in capillary tortuosity and polymorphism, which were also observed in the patients of both groups versus the control group, are referred to as disorders that are characteristic of T2DM. In decompensated T2DM, capillary bed structural and functional changes are found as a narrowing of the arterial capillary segment, an increase in the rate of remodeling, and enlargement of the PZ. Digital capillaroscopy opens up new possibilities for assessing the magnitude of changes in the microcirculatory system in DM and can simultaneously evaluate the efficiency of treatment, by monitoring the status of the microvasculature.

Vein wall remodeling in patients with acute deep vein thrombosis and chronic postthrombotic changes

Introduction A few studies have investigated venous wall remodeling after venous thrombosis by using rodent models. Such information is lacking in humans. This study was designed to determine the acute and chronic effects of thrombus on the vein wall. Methods Patients aged >16years with deep vein thrombosis diagnosed by duplex ultrasound were assessed by the use of case-control methodology. Those with recurring thrombotic episodes, cardiorespiratory disease, terminal cancer, morbid obesity, penetrating trauma or significant inflammation were excluded. High-resolution ultrasound was employed to determine wall thickness, with strict quality criteria and inclusion of only technically adequate ultrasound images. Results Data were collected from patientswith acute thrombosis (35), patients with chronic postthrombotic changes (15), and unaffected controls (32), with 853 total vein segments being analyzed. As compared with controls (mean 0.37mm; 95% confidence interval [CI]0.37-0.38mm), venous wall thickness was increased in acute (mean 0.63mm; 95%CI0.61-0.64mm) and postthrombotic (mean 0.85mm; 95%CI0.80-0.91mm) venous segments. Ipsilateral, contralateral and unaffected control vein segments were not different. Ipsilateral segments were thicker than controls in postthrombotic syndrome (PTS) patients, but not in acute patients. Multiple regression analyses demonstrated small impacts of age and sex on vein wall thickness. Conclusions Wall thickness increases in all lower-tcglimb venous segments of patients with acute andpostthrombotic disease. Age and sex may affect wall thickness, although further investigation is required to clarify their impact. The equivalence of ipsilateral and unaffected control segments suggests that acute vein wall remodeling is mediated through direct interaction with the thrombus, whereas remodeling in PTS patients may be affected by other factors.

Time-of-flight MR angiography in cerebral venous sinus thrombosis.

Recently, time-of-flight (TOF) and gadolinium-enhanced MR angiography (MRA) imaging have been used to demonstrate subacute intramural hematoma in cervical artery dissection and to detect intraplaque haemorrhage. Our aim was to perform an exploratory study to analyse if venous thrombus-related signal changes (potentially showing iso- or hyperintensity) in cerebral venous sinus thrombosis (CVST) could be observed on 3D-TOF MRA imaging. We analysed retrospectively MRIs of CVST patients in whom both contrast-enhanced MR venography (CEMRV) and 3D-TOF sequences were performed in the acute/subacute phase (i.e. <31days after symptom onset). The occluded sinus segments were defined on CEMRV. First, analyses of signal changes in occluded venous sinuses segments (defined by and unblinded to CEMRV) on native 3D-TOF images and morphological MRI sequences were performed. Second, a blinded (to CEMRV and other morphological MRI sequences) analysis was performed on 3D-TOF imaging assessing signal changes on 3D-TOF considering all sinus segments. Twenty-five CVST patients were included. 3D-TOF imaging showed signal changes (most often hyperintensity and less often isointensity) in 84% of the occluded sinus segments. Signal changes were observed in 91% of the occluded sinus segments on T1-weighted imaging, in 69% on T2-weighted imaging, in 68% on FLAIR, in 32% on DWI, and in 55% on T2*-weighted imaging. On blinded analysis, sensitivity of 3D-TOF sequences decreased to 80%, whereas specificity was only 65%. Abnormal signal in the venous sinuses on 3D-TOF may possibly help to suspect CVST, especially when CEMRV sequences lack.

Success Rate and Complications of Sharp Recanalization for Treatment of Central Venous Occlusions.

To evaluate success and safety of needle (sharp) recanalization as a method to re-establish access in patients with chronic central venous occlusions. Thirty-nine consecutive patients who underwent this procedure were retrospectively reviewed to establish success rate and associated complications. In all cases, a 21- or 22-gauge needle was used to restore connection between two chronically occluded segments after conventional wire and catheter techniques had failed. The needle was guided toward a target placed through a separate access by fluoroscopic guidance. When successful, the procedure was completed by placing a catheter, ballooning the segment, and/or stenting. The procedure was successful in 37 of the 39 patients (95%). The vast majority of the treated lesions were in the SVC and/or right innominate vein. Occlusions ranged in length between 10 and 110mm, and the average length of occluded venous segment was 40mm in the treated group. There were four minor (SIR classification B) complications involving pain management after the procedure. There were two major (SIR classification D) complications both of which involved hemorrhage into the pericardium treated with covered stents (5.1%). Sharp recanalization is a viable procedure for patients who have exhausted standard wire and catheter techniques. The operator performing this procedure should be familiar with potential complications so that they can be addressed urgently if needed.

Arterio-venous fetoplacental vascular geometry and hemodynamics in the mouse placenta

IntroductionThe fetoplacental vasculature network is essential for the exchange of nutrients, gases and wastes with the maternal circulation and for normal fetal development. The present study quantitatively compares arterial and venous morphological and functional differences in the mouse fetoplacental vascular network. MethodsHigh resolution X-ray micro-computed tomography was used to visualize the 3D geometry of the arterial and venous fetoplacental vasculature in embryonic day 15.5 CD-1 mice (n = 5). Automated image analysis was used to measure the vascular geometry of the approximately 4100 arterial segments and 3200 venous segments per specimen to simulate blood flow through these networks. ResultsBoth the arterial and venous trees demonstrated a hierarchical branching structure with 8 or 9 (arterial) or 8 (venous) orders. The venous tree was smaller in volume and overall dimensions than the arterial tree. Venous vessel diameters increased more rapidly than arteries with each successive order, leading to lower overall resistance, although the umbilical vein was notably smaller and of higher resistance than these scaling relationships would predict. Simulation of blood flow for these vascular networks showed that 57% of total resistance resides in the umbilical artery and arterial tree, 17% in the capillary bed, and 26% in the venous tree and umbilical vein. DiscussionA detailed examination of the mouse fetoplacental arterial and venous tree revealed features, such as the distribution of resistance and the dimension of the venous tree, that were both morphologically distinct from other vascular beds and that appeared adapted to the specialized requirements of sustaining a fetus.

Variability in quantitative analysis of atherosclerotic plaque inflammation using 18F-FDG PET/CT.

Background18F-FDG-PET(/CT) is increasingly used in studies aiming at quantifying atherosclerotic plaque inflammation. Considerable methodological variability exists. The effect of data acquisition and image analysis parameters on quantitative uptake measures, such as standardized uptake value (SUV) and target-to-background ratio (TBR) has not been investigated extensively.ObjectiveThe goal of this study was to explore the effect of several data acquisition and image analysis parameters on quantification of vascular wall 18F-FDG uptake measures, in order to increase awareness of potential variability.MethodsThree whole-body emission scans and a low-dose CT scan were acquired 38, 60 and 90 minutes after injection of 18F-FDG in six rheumatoid arthritis patients with high cardiovascular risk profiles.Data acquisition (1 and 2) and image analysis (3, 4 and 5) parameters comprised:1. 18F-FDG uptake time, 2. SUV normalisation, 3. drawing regions/volumes of interest (ROI’s/VOI’s) according to: a. hot-spot (HS), b. whole-segment (WS) and c. most-diseased segment (MDS), 4. Background activity, 5. Image matrix/voxel size.Intraclass correlation coefficients (ICC’s) and Bland Altman plots were used to assess agreement between these techniques and between observers. A linear mixed model was used to determine the association between uptake time and continuous outcome variables.Results1. Significantly higher TBRmax values were found at 90 minutes (1,57 95%CI 1,35–1,80) compared to 38 minutes (1,30 95%CI 1,21–1,39) (P = 0,024) 2. Normalising SUV for BW, LBM and BSA significantly influences average SUVmax (2,25 (±0,60) vs 1,67 (±0,37) vs 0,058 (±0,013)). 3. Intraclass correlation coefficients were high in all vascular segments when SUVmax HS was compared to SUVmax WS. SUVmax HS was consistently higher than SUVmax MDS in all vascular segments. 4. Blood pool activity significantly decreases in all (venous and arterial) segments over time, but does not differ between segments. 5. Image matrix/voxel size does not influence SUVmax.ConclusionQuantitative measures of vascular wall 18F-FDG uptake are affected mainly by changes in data acquisition parameters. Standardization of methodology needs to be considered when studying atherosclerosis and/or vasculitis.

Cortical bridging venous segment protruding into the inner skull depression: a potential site of hemorrhage at external ventriculostomy.

The cortical bridging venous segment protruding into the inner skull depression (CBVISD), a distinctive structure found in the calvarial convexity, may be a potential risk factor for hemorrhagic complications resulting from trephination. However, this subject has not been documented. In the present study, we explore the CBVISD using magnetic resonance imaging (MRI). A total of 94 patients underwent contrast-enhanced MRI. Distributions of the CBVISDs were recorded in two symmetrical regions of the frontal calvarial convexity. The lateral dimensions on both hemispheres were defined to range between 25 and 35mm from the midsagittal section. The anteroposterior axis was delimited anteriorly by the supraorbital bar and posteriorly by the coronal suture, which was further divided into four parts: the forehead (FH), anterior frontal (AF), FH-AF junctional, and posterior frontal (PF) regions. Analysis of the delineations revealed that the CBVISDs had variable shapes and sizes. They were identified on the right side in 40% of the 94 patients and in 41% on the left side. Among the 91 identified CBVISDs, 5.5% of the CBVISDs were located in the FH, 17.6% in the FH-AF, 34.1% in the AF, and 42.9% in the PF. The CBVISDs are most frequently located at the common trephination site of external ventriculostomy. Trephination performed in the FH and FH-AF junctional regions may be safer than that in more posterior frontal areas.

The effect of Diosmin on the blood proteome in a rat model of venous thrombosis

Diosmin is the aglycone moiety of diosmetin (3′,5,7 trihydroxy-4′methoxy radicals flavonoids), a naturally occurring flavone glycoside, whose antithrombotic effect was studied in rats. This study was designed to find the protein changes of venous thrombosis in Wistar rats comparing conditions with and without Diosmin treatment by two-dimensional gel electrophoresis (2-DE), and investigate the effect of a crucial protein known as CEP350 on human vascular endothelial cell growth.Through prior chromatographic purification with macroporous absorption resin (AB-8) and polyamide, Diosmin was isolated from Galium verum L. by solvent extraction, then purified to 98% purity using HPLC. Wistar rats were divided into control group, model group, and prevention group. And their venous thrombosis tissue segments were dissected and prepared for histopathological examination and detection of plasma protein C (PC). Next, proteomic analysis was performed with the samples. Low-abundance proteins of the three groups were separated by two-dimensional gel electrophoresis (2-DE). 2-DE analysis revealed that 191 protein spots were differentially expressed among those three groups. For protein identification, we selected six spots to use matrix assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI-TOF-MS) detection, and then do the homology search in NCBI database. Considering characteristics of these proteins, we proposed CEP350 is related to spindle assembly. Furthermore, we used Lipofectamine 2000 to transfect HUVECs with CEP350 siRNA and evaluated the extent of silencing using real time–polymerase chain reaction (RT-PCR). Cells were stained for immunofluorescence with tubulin-tracker red, and structural changes were analyzed using laser scanning confocal microscope.We concluded that CEP350 depletion decreased microtubule stability. Dosmin could modulate the assemble of spindle from unevenly distributing and protect body from varicose veins by regulating CEP350.

Endothelial Function Is Preserved in Veins Harvested by Either Endoscopic or Surgical Techniques

Endoscopic vein harvest for lower extremity arterial bypass grafting has beenquestioned due to concern for endothelial damage during procurement. We sought to compare nitric oxide (NO)-mediated endothelial-dependent relaxation (EDR) in vein segments harvested using open surgical techniques (OH) versus endoscopic vein harvest (EH) techniques. Saphenous vein segments were harvested for lower extremity bypass, and a single, minimally handled section of saphenous vein, free of branches, was taken from the end of the graft. Four 4-mm venous ring segments were then cut and mounted on force transducers. Segments were mounted in 37° oxygenated Krebs-Henseleit solution and maximally contracted using KCl. Individual ring segments that did not react to KCl were excluded from the study. Norepinephrine (NE) was used to achieve submaximal contraction. EDR was determined using increasing concentrations of bradykinin (BDK). Endothelial-independent relaxation (EIR) was confirmed using sodium nitroprusside. Two-way analysis of variance (ANOVA) was used to analyze differences between harvest techniques across BDK concentration and a Student's t-test was used to analyze single comparisons. Vein segments harvested from patients (n=13) led to 28 viable rings that exhibited a positive reaction to KCl (11 rings; 5 patients EH vs. 17 rings; 8 patients OH). Both vein groups achieved moderate relaxation to maximal BDK concentration, [10-6M]; (49.5% EH vs. 40.55% OH, P=0.270). Analysis by 2-way ANOVA for mean % relaxation for BDK concentration [10-11-10-6M] showed improved EDR in EH samples compared with OH (P=0.029). Mean nitrite/nitrate (NO(x)) tissue bath concentration measurements post-BDK were 139.8nM (EH) vs. 97.2nM (OH; P=0.264). Histology and positive factor VIII immunohistochemistry staining provided evidence for the presence of intact endothelium in our sample segments. EIR was preserved and was similar in the two groups. Endothelial function is preserved when utilizing endoscopic harvesting techniques. The advantages of minimally invasive vein procurement for lower extremity bypass can be obtained without concern for damaging venous endothelium.

The Unique Paired Retinal Vessels of the Gray Short-Tailed Opossum (Monodelphis domestica) and Their Relationship to Astrocytes and Microglial Cells.

In marsupials that possess a retinal vasculature, the arterial and venous segments, down to the smallest calibre capillaries, have been shown to occur in pairs. This pattern is seen in the marsupial central nervous system (CNS) but not in other tissues in this group or in any tissues in eutherian mammals. The present study aimed to determine if the gray short-tailed opossum (Monodelphis domestica), a south American marsupial, possesses double retinal vessels. Secondly, we investigated the relationship between vessels and astrocytes and microglia, which are known to play pivotal roles in the blood retinal barrier and immune surveillance respectively. Eyes from M. domestica between 2 months and 33 months of age were examined by bright field and fluorescein angiography, resin histology, and wholemount immunostaining. Retinal vessels in this marsupial always occur in closely related pairs with the arteriolar limb usually on the vitread aspect. Branches penetrate the retina to form layers of paired capillaries as far as the outer nuclear layer. Dense networks of GFAP+ astrocytes enveloped the vitread aspect of vessels. No particularly strong association with blood vessels and ramified Iba1+ and Ib4+ microglia was noted. M. domestica possessed the unusual paired vasculature and capillary loops arrangement previously described in the marsupial CNS. These observations in a small laboratory-friendly marsupial open up new frontiers to investigate the factors that regulate paired blood vessel development and the functional significance of this arrangement when compared to the anastomotic pattern observed in the retina of eutherian mammals. Anat Rec, 300:1391-1400, 2017. © 2017 Wiley Periodicals, Inc.

Recipient umbilical artery elongation (redundancy) in twin-twin transfusion syndrome

Chronic hypertension in adults causes arterial lengthening in major arteries, but the effects of early fetal hypertension on the twin-twin transfusion syndrome recipient's vascular architecture remains unknown. We hypothesize that arterial cord redundancy is related to recipient hypertension and subsequent heart failure. Our objectives were to: (1) establish a 3-dimensional color Doppler ultrasound method of measuring umbilical arterial length relative to its corresponding venous segment in the umbilical cord using artery vein angle; (2) compare recipient artery vein angle to gestational age-matched controls; and (3) test the association of artery vein angle with recipient heart failure. We compared 3 groups prospectively: twin-twin transfusion syndrome pregnancies undergoing fetoscopic laser surgery (preoperatively) and 2 groups of gestational age-matched controls: uncomplicated monochorionic-diamniotic twin pregnancies and healthy singletons. Using a 3-dimensional color-Doppler volume image of 5 cm of cord near the placental insertion, we traced the umbilical artery and vein producing umbilical artery:vein length, (artery vein index) and measured the artery vein angle between umbilical artery and vein. Correlation of artery vein angle to twin-twin transfusion syndrome stage, maximum vertical pocket, umbilical arterial indices, ductus venosus Doppler, and brain natriuretic peptide were performed. We used pulsed-wave and tissue Doppler to measure tissue Doppler velocities and indexed cardiac output and correlated these with artery vein angle. Comparative statistics, including multivariable linear regression, examined the relationship between umbilical arterial Doppler indices and artery vein angle. Artery vein angle and artery vein index correlated significantly (R2, 0.86; P < .0001), hence, artery vein angle was used for analysis. Mean artery vein angle was 33.1 ± 31.5 degrees in recipients (n= 44), 9.5 ± 6 degrees in monochorionic-diamniotic (n= 11; 22 fetuses), and 8.9 ± 8.3 degrees in singleton controls (n= 16) (P < .001). An artery vein angle ≥26 degrees (>95th percentile for controls) was measured in 52% recipients. Artery vein angle was higher in twin-twin transfusion syndrome stage 3R vs 1 (P= .001). Artery vein angle increased with increasing umbilical arterial pulsatility index (P < .001), and decreased with increasing resistance index (P= .02) after adjusting for gestational age. Interrater agreements to categorize abnormal artery vein angle values was 95% (P < .001). Abnormal ductus venosus Doppler and elevated recipient amniotic fluid N-terminal pro-brain natriuretic peptide/protein levels correlated significantly with artery vein angle. Abnormal artery vein angles were associated with decreased indexed cardiac output, lower tissue Doppler velocities, higher right-sided Tei indices, and severe tricuspid regurgitation. Umbilical arterial lengthening occurs in 52% of recipients and is associated with abnormal Doppler flows, low systolic tissue Doppler velocities, reduced cardiac output, and elevated markers of cardiac failure. This may reflect chronicity and severity of hypertension in the recipient fetus. Further research is needed to explore the mechanisms of elongation and long-term implications.

Hyperbaric oxygen inhibits venous neointimal hyperplasia following arteriovenous fistulization

Hypoxia following arteriovenous fistulization results in venous neointimal hyperplasia(VNH), potentially causing early arteriovenous fistula(AVF) dysfunction. In this study, we used hyperbaric oxygen(HBO) in a rabbit model of AVF to determine whether it could ameliorate early AVF failure. Chronic renal failure was induced by adenine in 96adult rabbits randomly divided into 3groups(n=32in each group). The sham+HBO group underwent sham operation and received HBO. The AVF alone group underwent fistulization, but did not receive HBO. The AVF+HBO group underwent fistulization and received HBO. Each group was further divided into 4subgroups of 8rabbits each that were euthanized at 1,7, 14or 28days post-operatively. At each time point, blood flow changes in the AVF venous segment were detected using a high-frequency duplex ultrasonography system. Immunohistochemical staining for proliferating cell nuclear antigen(PCNA), and hematoxylin and eosin staining were performed to evaluate VNH. Western blot analysis was performed to confirm the expression of hypoxia-inducible factor(HIF)-1α. At 14and 28days following HBO treatment, blood flow in the AVF+HBO group was greater than that at day0. The AVF+HBO group had a smaller ratio of intima to media area, a lower HIF-1α protein expression, and a smaller percentage of PCNA-positive cells in the proximal vein than did the AVF alone group. Our results thus suggest that continuous HBO treatment following AVF significantly inhibits VNH and promotes blood flow. Therefore, early AVF failure may be prevented by the use of HBO therapy.

Immobile cerebral veins in the context of positional brain shift: an undescribed risk factor for acute subdural hemorrhage

Changes in head position are thought to cause a degree of brain shift in the intracranial cavity. However, little is known on the concurrent shift of the cerebral veins. The present study aimed to investigate the positional shift of the cerebral veins that accompanies brain shift. Sagittal T2-weighted magnetic resonance imaging was performed on 21 consecutive patients lying in the supine and prone positions, using the same sequence. For each patient, imaging data were obtained for the two positions as a pair of images with morphologically best-matched cerebral contours. The subarachnoid spaces in the parasagittal frontal convexity showed variable reductions related to a postural change from a supine to a prone position, with a mean percent reduction (%Δ) of 17.8 ± 11.7%. Additionally, cerebral cisterns ventral to the brainstem and upper cervical cord were reduced in most patients when lying in a prone position, with a mean %Δ of 16.6 ± 8.7%. In contrast, none of these 130 pairs of identical venous segments located in the parasagittal cerebral convexity showed positional shift. Cadaveric dissections found that the major cortical veins were superficially upheld by the arachnoid membranes. The parasagittal major cortical and bridging veins do not seem to show positional shifts. Positional change in the posterior-anterior direction causes a shearing between the frontal cortices and the distributing veins and can be a risk factor for acute subdural hemorrhage, in case of severe head trauma.

Management of Cavoatrial Deep Venous Thrombosis: Incorporating New Strategies.

Cavoatrial deep venous thrombosis (DVT) is diagnosed with increasing prevalence. It can be managed medically with anticoagulation or with directed interventions aimed to efficiently reduce the thrombus burden within the target venous segment. The type of management chosen depends greatly on the etiology and chronicity of the thrombosis, existing patient comorbidities, and the patient's tolerance to anticoagulants and thrombolytic agents. In addition to traditional percutaneous catheter-based pharmacomechanical thrombolysis, other catheter-based suction thrombectomy techniques have emerged in recent years. Each therapeutic modality requires operator expertise and a coordinated care paradigm to facilitate successful outcomes. Open surgical thrombectomy is alternatively reserved for specific patient conditions, including intolerance of anticoagulation, failed catheter-based interventions, or acute emergencies.

Preoperative computer simulation for planning of vascular access surgery in hemodialysis patients.

The arteriovenous fistula (AVF) is the preferred vascular access for hemodialysis patients. Unfortunately, 20-40% of all constructed AVFs fail to mature (FTM), and are therefore not usable for hemodialysis. AVF maturation importantly depends on postoperative blood volume flow. Predicting patient-specific immediate postoperative flow could therefore support surgical planning. A computational model predicting blood volume flow is available, but the effect of blood flow predictions on the clinical endpoint of maturation (at least 500 mL/min blood volume flow, diameter of the venous cannulation segment ≥4 mm) remains undetermined. A multicenter randomized clinical trial will be conducted in which 372 patients will be randomized (1:1 allocation ratio) between conventional healthcare and computational model-aided decision making. All patients are extensively examined using duplex ultrasonography (DUS) during preoperative assessment (12 venous and 11 arterial diameter measurements; 3 arterial volume flow measurements). The computational model will predict patient-specific immediate postoperative blood volume flows based on this DUS examination. Using these predictions, the preferred AVF configuration is recommended for the individual patient (radiocephalic, brachiocephalic, or brachiobasilic). The primary endpoint is FTM rate at six weeks in both groups, secondary endpoints include AVF functionality and patency rates at 6 and 12 months postoperatively. ClinicalTrials.gov (NCT02453412), and ToetsingOnline.nl (NL51610.068.14).

Lower limbs venous kinetics and consequent impact on drainage direction.

Background Literature concerning the lower limbs physiological venous haemodynamics is still lacking of reference velocity values and consequent impact on drainage direction. Aim of the present study is to assess the flow velocities in the different venous compartments, evaluating the possible Venturi effect role, thus finding clues for the identification of the physical model governing the flow direction. Methods Thirty-six lower limbs underwent a velocity and diameters echo-color-Doppler assessment in several anatomical point of analysis along both the deep and superficial venous systems. The investigation protocol included and compared two different manoeuvres to elicit the flow: manual calf compression/relaxation (CR) and active foot dorsiflexion (AFD). Both peak systolic (PSV) and time average velocities (TAV) were measured. Results The different venous segments demonstrated an overlap among the velocity values and the anatomical subdivision of the deep and superficial compartments. At the CR, TAV was 34 ± 12 cm/s in the deep venous system (N1), 15 ± 7 cm/s in the saphenous system (N2), 5 ± 2 cm/s in the saphenous tributaries (N3); PSV was 89 ± 35 cm/s in N1, 34 ± 16 cm/s in N2, 11 ± 4 cm/s in N3, p < 0.05. At the AFD, TAV was 33 ± 13 cm/s in N1, 15 ± 7 in N2, 9 ± 5 in N3; PSV was 83 ± 35 in N1, 32 ± 17 in N2, 15 ± 4 in N3, p < 0.05. A diameter decrease was reported from N1 to N3 ( p < 0.05). Conclusion This investigation provides evidences of the velocity decrease from the deepest to the most superficial compartments. These data introduce the Venturi effect as potential factor in the flow aspiration from the tributary to the deeper veins. The reported data represent a first step towards an objective evaluation of the physic laws governing the drainage. These values can constitute the basis for further investigations in pathological and post-procedural scenarios.

Towards a Classification of Left Common Iliac Vein Compression Based on Triplanar Phlebography

Introduction: There is currently no consistent classification of the extent of left common iliac vein compression syndromes such that clinicians working in the area have a common terminology. Hypothesis: To create a classification of left common iliac vein compression based on the end point of triplanar pelvic phlebogrpahy. Methods: Based on 61 consecutive patients found to have left common iliac vein compression on triplanar phlebography in the course of treatment of venous disease, clinical presentation and symptomatology were retrospectively used to create a classification of left common iliac vein compression. Treatment of left common iliac vein compression was also retrospectively correlated with staging. Results: The following classification was arrived at: Stage 0, no compression and no intraluminal fibrous bands; Stage 1, evidence of compression by surrounding anatomical structures with or without the presence of fibrous bands; Stage 2: evidence of compression with or without fibrous bands as evidenced by cross-pelvic collaterals; Stage 3: compression of the left common iliac vein. Fibrous bands replaced by localised occlusion, with collateralisation and no involvement of adjacent venous segments; Stage 4a: as for Stage 3 but with the addition of thrombotic involvement of adjacent venous segments; Stage 4b: as for Stage 4a but with involvement of distal venous segments, femoral and popliteal. Stages 3, 4a or 4b correlated well with clinical presentations of DVT, PE, venous ulceration, vulval or cross-pelvic collaterals, ipsilateral limb swelling and claudication. The presence of varicose veins or recurrent varicose veins was a common finding amongst all groups. Conclusion: Acceptance of this classification system would provide a common terminology to allow more transparent assessment of modalities of treatment for this condition.

Heterogeneity in Post-Thrombotic Vein Wall Remodeling

Post-thrombotic (PT) vein wall remodeling after thrombosis begins early after thrombus deposition and may persist even after thrombus resolution. The chronic luminal changes that occur have not been well characterized in PT patients. This study was designed to assess the extent and variability of chronic venous wall remodeling in the lower extremities. This prospective controlled study evaluated PT adult patients who presented with deep venous thrombosis (DVT) of >6 months in common femoral, femoral, popliteal, and axial calf veins as diagnosed by duplex ultrasound. Patients with recurrent DVT in the ipsilateral limb, penetrating trauma, complete or partial luminal obstruction, synechiae, or any other conditions affecting venous architecture were excluded. Normal ipsilateral and contralateral limb segments were included as control measurements when available. In all segments, venous wall thickness was measured using real-time high-definition zoom with a high-resolution linear array transducer. Only ultrasound images obtained under the best acoustic window at multiple angles to avoid slice thickness and off beam artifacts with distinguishable venous wall segments were included. For each venous segment with a smooth luminal surface, three measurements were obtained and the average value was used. In instances in which the lumen/blood interface was not uniform but rather irregular, three additional measurements were obtained and averaged from the heterogeneous area. Twenty-five PT patients (95 PT segments and 75 nonaffected segments) and 32 control patients (332 segments) were evaluated. Mean vein wall thickness was significantly higher in both the smooth (0.8 mm) and heterogeneous segments (1.1 mm) in PT patients compared with controls (0.370 mm) for all segments (P < .001). Segments with heterogeneous thickness were seen in 72% of patients. These heterogeneous regions were 1.40× (range, 1.25-1.48×) thicker than immediately adjacent PT segments and 2.89× (range, 2.6-3.18×) thicker than corresponding controls (P < .001). This prospective preliminary study suggests that the vein wall thickness at the PT stage is significantly elevated. On the same limb, it is common to find both smooth and heterogeneous areas. Detection of the chronic luminal changes may provide useful information in treating patients never formally diagnosed with DVT for the following reasons: it may allow the administration of chemical prophylaxis when surgery is required; it may lower the patient's expectations when superficial vein treatment is performed; and it could encourage the use of compression stockings.

The effects of diosmin and hesperidin on capillary blood flow of upper limbs in patients with secondary Raynaud’s syndrome

The article discusses the effects of diosmin and hesperidin on capillary blood flow in patients with secondary Raynaud's syndrome (RS). Raynaud's syndrome a difficult problem of modern angiology, since in its development there is a large range of disorders of the capillary blood flow of the limbs. Currently, the main way of therapy in patients with secondary Raynaud's syndrome is the use of either calcium channel blockers (if angiospastic stage of the disease), or prostaglandins of group E1 (with tropho-paralytic stage of secondary RS). However, pharmacological effects of calcium channel blockers (vasodilation) and prostaglandins (vasodilation, antiproliferative, anti-inflammatory etc.) do not allow impact on all violations of capillary blood flow, occurs when the Raynaud's syndrome. In this regard, the task was to study the reaction of capillary blood flow of the fingers of the hands on the concomitant use of drugs based on diosmin and hesperidin. A prerequisite for the use of a combination of diosmin and hesperidin in the treatment of RS was based on data about their impact on the state of the venous segment of the capillary bed and perivascular oedema. To conduct the study was established two groups of patients (22 in each group). The main criterion for inclusion of patients in the study was the presence of newly identified Raynaud's syndrome of angiospastic or tropho-paralytic stage of the disease. The main exclusion criteria was the presence of necrotic stage of the disease. In the first group of patients therapy was carried out using only vasodilators. In the second group (comparison group) with the addition of a combination of diosmin and hesperidin (tablets Venarus used in a dose 500 mg 2 times per day). The condition of capillary blood flow in this study was estimated by the method of videocapillaroscopy (VCS). Statistical data processing was performed using a criterion of statistical significance (P-value). The study revealed the significant impact of a combination of diosmin and hesperidin for parameters of capillary blood flow that correlated with clinical improvements - reduction of oedema of the fingers of the hands.

Adaptive and Pathological Reshuffling in the Venous Wall in Special Hemodynamic Conditions-Acquired Arteriovenous Fistula.

ABSTRACT: Hemodialysis and peritoneal dialysis are the two possible choices in chronic renal disease in the uremic stage. Native arteriovenous fistula is susceptible to complications, some posing vital risk and requiring prompt treatment. We present the case of a patient undergoing hemodialysis on native AVF. An aneurism developed progressively on the arterialized cephalic vein. The AVF was abolished by closing the arteriotomy with a venous patch and excising the aneurismal venous segment. The pathology exam of the surgical specimen showed unequal vessel wall thickness due to hyperplasia of the media and subintimal space, with calcifications within the hyperplastic media.