Disturbed flow in the juxta-anastomotic area of an arteriovenous fistula correlates with endothelial loss, acute thrombus formation, and neointimal hyperplasia.

Clinical failure of arteriovenous neointimal hyperplasia (NIH) fistulae (AVF) is frequently due to juxta-anastomotic NIH (JANIH). Although the mouse AVF model recapitulates human AVF maturation, previous studies focused on the outflow vein distal to the anastomosis. We hypothesized that the juxta-anastomotic area (JAA) has increased NIH compared with the outflow vein. AVF was created in C57BL/6 mice without or with chronic kidney disease (CKD). Temporal and spatial changes of the JAA were examined using histology and immunofluorescence. Computational techniques were used to model the AVF. RNA-seq and bioinformatic analyses were performed to compare the JAA with the outflow vein. The jugular vein to carotid artery AVF model was created in Wistar rats. The neointima in the JAA shows increased volume compared with the outflow vein. Computational modeling shows an increased volume of disturbed flow at the JAA compared with the outflow vein. Endothelial cells are immediately lost from the wall contralateral to the fistula exit, followed by thrombus formation and JANIH. Gene Ontology (GO) enrichment analysis of the 1,862 differentially expressed genes (DEG) between the JANIH and the outflow vein identified 525 overexpressed genes. The rat jugular vein to carotid artery AVF showed changes similar to the mouse AVF. Disturbed flow through the JAA correlates with rapid endothelial cell loss, thrombus formation, and JANIH; late endothelialization of the JAA channel correlates with late AVF patency. Early thrombus formation in the JAA may influence the later development of JANIH.NEW & NOTEWORTHY Disturbed flow and focal endothelial cell loss in the juxta-anastomotic area of the mouse AVF colocalizes with acute thrombus formation followed by late neointimal hyperplasia. Differential flow patterns between the juxta-anastomotic area and the outflow vein correlate with differential expression of genes regulating coagulation, proliferation, collagen metabolism, and the immune response. The rat jugular vein to carotid artery AVF model shows changes similar to the mouse AVF model.

Dyspnea, Elevated Jugular Venous Pulse, and Lower Extremity Edema in the Setting of Interstitial Lung Disease in a Patient Who Has Undergone Liver and Kidney Transplantation.

CASE PRESENTATION: A 64-year-old man with a past medical history of alcoholic cirrhosis with resultant hepatorenal syndrome requiring kidney and liver transplantation 10 years previously sought treatment at the ED with progressive lower-extremity edema and dyspnea. After noting worsening shortness of breath and cough as an outpatient, he had been referred to a pulmonary clinic and was undergoing a workup for interstitial lung disease (ILD). He had been started on prednisone 40 mg/d after a lung biopsy 4 months before admission. He was also receiving chronic immunosuppression with tacrolimus and mycophenolate mofetil. He had noted worsening of edema since starting prednisone.

Jugular Venous Reflux Can Mimic Posterior Fossa Dural Arteriovenous Fistulas on MRI-MRA.

Dural arteriovenous fistulas (DAVFs) are high-flow acquired shunts that can carry high risk of intracranial hemorrhage. Because DAVFs can often be managed by endovascular means, early and accurate diagnosis can markedly improve patient morbidity. Time-of-flight and arterial spin-labeling MRA have increased the diagnostic utility of MRI for DAVF by showing hemodynamic rather than anatomic evidence of shunting. The purpose of this article is to describe the cases of seven patients who had co-localization of arterial spin-labeling signal intensity and time-of-flight flow-related enhancement in the left skull base, resulting in a misdiagnosis of DAVF and a recommendation for catheter angiography by the interpreting radiologist. Benign jugular venous reflux is identified as a common mechanism in each case, and the physiology behind this imaging pitfall is described. An algorithmic diagnostic approach to differentiating physiologic venous reflux from true posterior skull base DAVFs is presented.

Anticoagulation Strategies in the Management of Lemierre Syndrome: A Systematic Review of the Literature.

OBJECTIVE: To determine the optimal anticoagulation strategy in patients diagnosed with Lemierre Syndrome (LS). DATA SOURCES: A systematic review in accordance with PRISMA guidelines was conducted using PubMed, MEDLINE, Scopus, ProQuest, and CINAHL from January to April 2020. Search terms included "Lemierre Syndrome" AND "anticoagulation" NOT "prophylaxis" OR "atrial fibrillation," in addition to a list of parenteral and oral anticoagulants. Adult patients who developed a clot and required systemic anticoagulation as a result of LS were included in this review. STUDY SELECTION AND DATA EXTRACTION: A total of 4180 records were initially identified, though following the removal of duplicates and nonrelevant entries, 216 full-text articles were reviewed for inclusion; 13 articles were ultimately included. DATA SYNTHESIS: The majority (11/14) of patients developed thromboses of the internal jugular veins, which corresponds to the pathophysiology of LS. Anticoagulation strategies were varied in the included literature, though 12/14 patients initially received a parenteral product. Two patients received a direct-acting oral anticoagulant (DOAC) following either intravenous heparin or subcutaneous enoxaparin and had outcomes similar to patients transitioned to warfarin. RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE: Anticoagulation in LS is a clinical controversy because the thromboembolic events have rarely led to significant complications; thrombi typically resolve independently, and concerns for bleeding risks are well founded; however, this review indicates both the efficacy and safety of anticoagulation. CONCLUSIONS: Anticoagulation is both efficacious and safe in LS, including treatment using a DOAC. Although further studies are needed, clinicians should consider a duration of anticoagulation of 6 to 12 weeks.

The effects of internal jugular vein compression for modulating and preserving white matter following a season of American tackle football: A prospective longitudinal evaluation of differential head impact exposure.

The purpose of this clinical trial was to examine whether internal jugular vein compression (JVC)-using an externally worn neck collar-modulated the relationships between differential head impact exposure levels and pre- to postseason changes in diffusion tensor imaging (DTI)-derived diffusivity and anisotropy metrics of white matter following a season of American tackle football. Male high-school athletes (n = 284) were prospectively assigned to a non-collar group or a collar group. Magnetic resonance imaging data were collected from participants pre- and postseason and head impact exposure was monitored by accelerometers during every practice and game throughout the competitive season. Athletes' accumulated head impact exposure was systematically thresholded based on the frequency of impacts of progressively higher magnitudes (10 g intervals between 20 to 150 g) and modeled with pre- to postseason changes in DTI measures of white matter as a function of JVC neck collar wear. The findings revealed that the JVC neck collar modulated the relationships between greater high-magnitude head impact exposure (110 to 140 g) and longitudinal changes to white matter, with each group showing associations that varied in directionality. Results also revealed that the JVC neck collar group partially preserved longitudinal changes in DTI metrics. Collectively, these data indicate that a JVC neck collar can provide a mechanistic response to the diffusion and anisotropic properties of brain white matter following the highly diverse exposure to repetitive head impacts in American tackle football. Clinicaltrials.gov: NCT# 04068883.

Measurement of the Hepatic Venous Pressure Gradient and Transjugular Liver Biopsy.

Here we provide a detailed protocol describing the clinical procedure of hepatic venous pressure gradient (HVPG) measurement in patients with advanced chronic liver disease followed by an instruction for transjugular biopsy. Under local anesthesia and ultrasound guidance, a catheter introducer sheath is placed in the right internal jugular vein. Using fluoroscopic guidance, a balloon catheter is advanced into the inferior vena cava (IVC) and inserted into a large hepatic vein. Correct and sufficient wedge position of the catheter is ensured by injecting contrast media while the balloon is blocking the outflow of the cannulated hepatic vein. After calibrating the external pressure transducer, continuous pressure recordings are obtained with triplicate recordings of the wedged hepatic venous pressure (WHVP) and free hepatic venous pressure (FHVP). The difference between FHVP and WHVP is referred to as HVPG, with values ≥10 mm Hg indicating clinically significant portal hypertension (CSPH). Before removing the catheter, pressure readings obtained in the IVC at the same level, as well as the right atrial pressure are recorded. Finally, a transjugular liver biopsy can be obtained via the same vascular route. Different systems are available; however, core biopsy needles are preferred over aspiration needles, especially for cirrhotic livers. Again, under fluoroscopic guidance a biopsy needle introducer sheath is advanced into an hepatic vein. Next, the transjugular biopsy needle is gently advanced through the introducer sheath: (i) in case of aspiration biopsy, the needle is advanced into the liver parenchyma under aspiration and then removed quickly, or (ii) in case of a core biopsy, the cutting-mechanism is triggered inside the parenchyma. Several separate passages can be safely performed to obtain sufficient liver specimens via transjugular biopsy. In experienced hands, the combination of these procedures takes about 30-45 min.

A rat arteriovenous graft model using decellularized vein.

BACKGROUND: The high rate of clinical failure of prosthetic arteriovenous grafts continues to suggest the need for novel tissue-engineered vascular grafts. We tested the hypothesis that the decellularized rat jugular vein could be successfully used as a conduit and that it would support reendothelialization as well as adaptation to the arterial environment. MATERIALS AND METHODS: Autologous (control) or heterologous decellularized jugular vein (1 cm length, 1 mm diameter) was sewn between the inferior vena cava and aorta as an arteriovenous graft in Wistar rats. Rats were sacrificed on postoperative day 21 for examination. RESULTS: All rats survived, and grafts had 100% patency in both the control and decellularized groups. Both control and decellularized jugular vein grafts showed similar rates of reendothelialization, smooth muscle cell deposition, macrophage infiltration, and cell turnover. The outflow veins distal to the grafts showed similar adaptation to the arteriovenous flow. Both CD34, CD90 and nestin positive cells, as well as M1-type and M2-type macrophages accumulated around the graft. CONCLUSIONS: This model shows that decellularized vein can be successfully used as an arteriovenous graft between the rat aorta and the inferior vena cava. Several types of cells, including progenitor cells and macrophages, are present in the host response to these grafts in this model. This model can be used to test the application of arteriovenous grafts before conducting large animal experiments.

Cardiac Variation of Internal Jugular Vein as a Marker of Volume Change in Hemorrhagic Shock.

BACKGROUND: Fluid resuscitation, which is critical to counter acute hemorrhagic shock, requires prompt and accurate intravascular volume estimation for optimal fluid administration. This study aimed to evaluate whether cardiac variation of internal jugular vein (IJV), evaluated by ultrasonography, could detect hypovolemic status and predict response to fluid resuscitation. METHODS: Patients undergoing autologous blood transfusion for elective surgery who were prospectively enrolled at the study blood donation center between August 2014 and January 2015. Vertical B-mode ultrasonography movies of IJV were recorded at five timepoints during blood donation: before donation, during donation, end of donation, end of fluid replacement, and after hemostasis. Cardiac variation of the IJV area and circumference were objectively measured using an automated extraction program together with blood pressure and heart rate. RESULTS: A total of 140 patients were screened, and data from 104 patients were included in the final analyses. Among the variables analyzed, only collapse index area and collapse index circumference could detect both intravascular volume loss and response to fluid administration. CONCLUSIONS: Cardiac variation of IJV may be a reliable indicator of intravascular volume loss and response to fluid administration in hemorrhagic shock.

Increase of wall shear stress caused by arteriovenous fistula reduces neointimal hyperplasia after stent implantation in healthy arteries.

BACKGROUND AND OBJECTIVES: Wall shear stress plays a critical role in neointimal hyperplasia after stent implantation. It has been found that there is an inverse relation between wall shear stress and neointimal hyperplasia. This study hypothesized that the increase of arterial wall shear stress caused by arteriovenous fistula could reduce neointimal hyperplasia after stents implantation. METHODS AND RESULTS: Thirty-six male rabbits were randomly divided into three groups: STENT, rabbits received stent implantation into right common carotid artery; STENT/arteriovenous fistula, rabbits received stent implantation into right common carotid artery and carotid-jugular arteriovenous fistula; Control, rabbits received no treatment. After 21 days, stented common carotid artery specimens were harvested for histological staining and protein expression analysis. In STENT group, wall shear stress maintained at a low level from 43.2 to 48.9% of baseline. In STENT/arteriovenous fistula group, wall shear stress gradually increased to 86% over baseline. There was a more significant neointimal hyperplasia in group STENT compared with the STENT/arteriovenous fistula group (neointima area: 0.87 mm2 versus 0.19 mm2; neointima-to-media area ratio: 1.13 versus 0.18). Western blot analysis demonstrated that the protein level of endothelial nitric oxide synthase in STENT group was significantly lower than that in STENT/arteriovenous fistula group, but the protein levels of proliferating cell nuclear antigen, vascular cell adhesion molecule 1, phospho-p38 mitogen-activated protein kinase (Pp38), and phospho-c-Jun N-terminal kinase in STENT group were significantly higher than that in the STENT group. CONCLUSION: High wall shear stress caused by arteriovenous fistula as associated with the induction in neointimal hyperplasia after stent implantation. The underlying mechanisms may be related to modulating the expression and activation of endothelial nitric oxide synthase, vascular cell adhesion molecule 1, p38, and c-Jun N-terminal kinase.

General Anesthesia Alters Intracranial Venous Pressures During Transverse Sinus Stenting.

INTRODUCTION: Pressure gradients across venous stenosis are used as a marker for physiologically significant narrowing in idiopathic intracranial hypertension. Performing such measurements under conscious sedation (CS) more likely reflects physiologic conditions, but can be uncomfortable, leading some operators to perform measurement under general anesthesia (GA), though this may not be equivalent. METHODS: We performed a retrospective analysis of patients who received endovascular transverse sinus stenting due to idiopathic intracranial hypertension between August 2013 and May 2017. Patients' demographics and anesthetic parameters were collected along with venous pressure measurements. RESULTS: We identified 15 patients (14 women). The mean (SD) age was 30.5 (9.0) years and the mean body mass index (SD) was 39.5 (9.6) kg/m2. After measurements during CS, GA was induced with propofol and maintained with a volatile anesthetic. The median [IQR; range] transverse sinus pressure gradient under CS was 18 [12, 25; 6-38] mmHg compared with 14 [8, 21; 3-26] mm Hg under GA. The median [IQR; range] pressure gradient change after initiation of GA was -3 [-12, 0; -22 to 9] mm Hg (P = 0.014). After correction for increases in internal jugular vein pressures associated with assumption of GA, the median [IQR; range] gradient change was -11 [-12.5, -5; -22 to 0] mm Hg (P < 0.001). CONCLUSIONS: The transition from CS to GA results in clinically meaningful reductions in transverse sinus gradients in idiopathic intracranial hypertension. Correction for increases in the internal jugular vein pressures reveals even more dramatic reductions in transverse sinus gradients.

Feasibility of bile duct as venous graft for venous reconstruction in pancreatic surgery: An animal experimental study.

OBJECTIVE: Pancreatic cancer is a kind of high malignant tumor with a poor prognosis. The aim is to determine whether the dilated bile duct can be used to reconstruct the vessels. METHODS: An animal model of jugular vein and portal vein reconstruction was established using the bile duct. A total of 20 landrace pigs were selected to undergo jugular vein reconstruction or portal vein reconstruction using the bile duct as a patch or bridge. The patency was evaluated by color Doppler, the reconstructed segments were removed and examined macroscopically and histologically at specified intervals, and the results were compared with synthetic vessels (IMPRA straight, 10s03-19). RESULTS: The lumen was patent, although a low level thrombosis was observed when jugular or portal vein patching was used. For bridging, stenosis of the lumen was observed, and necrosis appeared when the bile duct was used for bridging, indicating that it is feasible to reconstruct the jugular vein and portal vein with a bile duct patch. However, the bridge was not feasible possibly due to loss of blood supply, and consequent necrosis and fibrosis. CONCLUSION: The bile duct is technically feasible, but the outcomes are unsatisfactory.

Retrograde blood flow in the internal jugular veins of humans with hypertension may have implications for cerebral arterial blood flow.

OBJECTIVES: To use multi-parametric magnetic resonance imaging (MRI) to test the hypothesis that hypertensives would have higher retrograde venous blood flow (RVBF) in the internal jugular veins (IJV) vs. normotensives, and that this would inversely correlate with arterial inflow and gray matter, white matter, and cerebrospinal fluid volumes. METHODS: Following local institutional review board approval and written consent, a prospective observational 3-T MRI study of 42 hypertensive patients (53 ± 2 years, BMI 28.2 ± 0.6 kg/m2, ambulatory daytime systolic BP 148 ± 2 mmHg, ambulatory daytime diastolic BP 101 ± 2 mmHg) and 35 normotensive patients (48 ± 2 years, BMI 25.2 ± 0.8 kg/m2, ambulatory daytime systolic BP 119 ± 3 mmHg, ambulatory daytime diastolic BP 90 ± 2 mmHg) was performed. Phase contrast imaging calculated percentage retrograde venous blood flow (%RVBF), brain segmentation estimated regional brain volumes from 3D T1-weighted images, and pseudo-continuous arterial spin labeling measured regional cerebral blood perfusion. Statistical analysis included two-sample equal variance Student's T tests, two-way analysis of variance with Tukey's post hoc correction, and permutation-based two-group general linear modeling (p < 0.05). RESULTS: In the left IJV, %RVBF was higher in hypertensives (6.1 ± 1.5%) vs. normotensives (1.1 ± 0.3%, p = 0.003). In hypertensives, there was an inverse relationship of %RVBF (permutation-based general linear modeling) to cerebral blood flow in several brain regions, including the left occipital pole and the cerebellar vermis (p < 0.01). Percentage retrograde flow in the left IJV correlated inversely with the total matter volume (gray plus white matter volume) in hypertensives (r = - 0.49, p = 0.004). CONCLUSION: RVBF in the left IJV is greater in hypertensives vs. normotensives and is linked to regional hypoperfusion and brain total matter volume. KEY POINTS: • Hypertensive humans have higher retrograde cerebral venous blood flow, associated with regional brain hypoperfusion and lower tissue volume, compared with controls. • Cerebral retrograde venous blood flow may add further stress to already hypoperfused tissue in hypertensive patients. • The amount of retrograde venous blood flow in hypertensive patients may predict which patients might be at higher risk of developing cerebral pathologies.

Jugular venous reflux may mimic type I dural arterio-venous fistula on arterial spin labeling magnetic resonance images.

PURPOSE: Previous studies have shown that arterial spin-labeling (ASL) has high sensitivity and specificity for detecting dural arteriovenous fistulas (DAVFs). However, in case of jugular venous reflux (JVR), the labeled protons in the jugular vein may lead to a venous hypersignal in the jugular vein, sigmoid, and transverse sinus on ASL images and mimic DAVF. METHODS: To ascertain this hypothesis, two blinded senior neuroradiologists independently and retrospectively reviewed randomized ASL images and graded the likelihood of DAVF on a 5-point Likert scale in 2 groups of patients: (i) 13 patients with angiographically proven type I DAVF; and (ii) 11 patients with typical JVR diagnosed on the basis of clinical and MR imaging data, first using ASL alone, and second using ASL together with all of the sequences including 4D CE MRA. RESULT: A dural venous ASL signal was seen in 11 patients with type I DAVF and in all the 11 patients with JVR, with no distinctive pattern between the two. The mean Likert score was "very likely" in DAVF and JVR patients when using ASL alone (k = 0.71), and "very unlikely" for JVR versus "very likely" for DAVF when using all the sequences available (k = 0.92). CONCLUSION: Our study shows that JVR can mimic DAVF on ASL images with potential implications for patient care. The detection of DAVFs should be based on additional MR sequences such as TOF-MRA and 4D CE MRA to exclude JVR and to avoid unnecessary DSAs.

Transposition of external jugular to proximal internal jugular vein for relief of venous thoracic outlet syndrome and maintenance of arteriovenous fistula access for chronic hemodialysis: A new approach.

We are reporting a case of venous thoracic outlet syndrome with recurrent subclavian vein thrombosis in the setting of an ipsilateral brachiocephalic arteriovenous fistula for hemodialysis that was malfunctioning due to the central vein obstruction. The patient also had a concomitant external jugular vein origin stenosis. Given her body habitus and aversion to recovery after traditional first rib resection, we elected for an alternative treatment with an external jugular vein to internal jugular vein transposition with balloon angioplasty of the stenosed external jugular origin segment. The goal of this was to provide simultaneous relief of her outlet obstruction symptoms and salvage her dialysis access with a less invasive technique.

Sirtuin 3 Therapy Attenuates Aging Expression, Oxidative Stress Parameters, and Neointimal Hyperplasia Formation in Vein Grafts.

BACKGROUND: Vein graft (VG) failure due to neointimal hyperplasia remains an important and unresolved problem in cardiovascular surgery. Sirtuin3 (SIRT3) is associated with oxidative stress and lifespan. We aimed to measure SIRT3 expression in the veins of humans and rats during aging, explore the inhibitory effects of SIRT3 on vascular smooth muscle cell (VSMC) proliferation and neointimal hyperplasia in VGs, and investigate the underlying mechanisms. METHODS: SIRT3 mRNA and protein levels in saphenous veins of young and older humans and in veins of young and old rats were measured by quantitative real-time polymerized chain reaction (PCR) and Western blot analysis. Young and old male rats were randomized to the control (control), graft (graft), adenovirus-encoding green fluorescent protein (Ad-GFP), and adenovirus encoding SIRT3 (Ad-SIRT3) groups. At 7 days after operation, the mRNA and protein levels of SIRT3 and endothelial nitric oxide synthase (eNOS) were measured by quantitative real-time PCR and Western blot analysis. The mRNA levels and enzyme activity of manganese superoxide dismutase (MnSOD) and catalase (CAT) were measured by quantitative real-time PCR and enzymatic activity assay kits, and total nitric oxide (NO) levels were measured by biochemical assay kits. Histomorphometric analysis of VGs and immunohistochemical staining for proliferative activity were performed at 4 weeks after operation. The hemodynamic parameters of the VGs were also measured by ultrasonic examination. RESULTS: SIRT3 mRNA and protein levels were lower in older human and rat veins than in younger human and rat veins. Ad-SIRT3 treatment significantly increased the expression and concentration of SIRT3, MnSOD, CAT, eNOS, and NO in VGs at 7 days after operation. Ad-SIRT3 gene transfer reduced the neointimal thickness and neointimal area/media area ratio in the VGs of the Ad-SIRT3 groups compared with the graft and Ad-GFP groups, especially in old rats. Proliferative activity was lower in the Ad-SIRT3 groups than in the other groups. The hemodynamic parameters of VGs were obviously improved in the Ad-SIRT3 groups. CONCLUSIONS: SIRT3 expression decreases in the veins of humans and rats during aging. Furthermore, SIRT3 overexpression can significantly reduce VSMC proliferation and neointimal hyperplasia in VGs. Local intravenous delivery of adenovirus encoding SIRT3 may be a promising gene therapy for preventing VG failure.

A new marker identification of high risk stroke patients: Jugular saturation.

OBJECTIVES: The aim of this prospective study; to investigate in emergency patients with stroke the relationship between jugular saturation and National Institutes of Health Stroke Scale (NIHSS), lesion volume and mortality score. MATERIALS AND METHODS: In this prospective study, 82 patients who fulfilling the criteria for inclusion in diagnosed with were enrolled in the study. Patients' demographic data, comorbid conditions and stroke type were recorded. The arterial blood pressure, heart rate, and consciousness were recorded at the emergency department. Glasgow Coma Score (GCS) and National Health Institutions Stroke Scale (NIHSS) scores were calculated. Complete Blood Count (CBC) and biochemical values were obtained at the time of admission to the emergency department. Arterial blood gas and jugular venous blood gas were taken and pO2, SpO2 and lactate values were recorded. Patients were grouped according to jugular desaturation (<50%). After imaging, the lesion was located by a specialist radiologist and the lesion volume was calculated. Afterwards, it was followed up by means of the hospital registry system where the patients were followed up (service, intensive care), hospitalization time and whether in-hospital mortality occurred. RESULTS: 82 patients were included in the study. Of the 82 patients, 36 (43.9%) were male and 46 (56.1%) were female. The mean age was 69.8 ±â€¯13.3. Patients were divided into two groups, jugular venous saturation <50% and ≥50%. 16 patients with J.SpO2 <50% were detected. There was no difference between the two groups in terms of age, sex, Glasgow Coma Scale (GCS), National Health Institutions Stroke Scale (NIHSS) score, laboratory data other than hemoglobin and lesion volume (p > 0,05). In-hospital mortality occurred in 9 (13.6%) of patients with J.SpO2 ≥% 50; In the group with J.SpO2 < % 50, 6 patients (37.5%) died within the hospital and this difference was statistically significant (p < 0,05). CONCLUSION: SjVO2 measurement can be used to identify high-risk stroke patients and to direct critical interventions. However, no correlation was found between this value and lesion volume and NIHSS scale.