Whole-lesion assessment of volume and signal changes after sclerotherapy of extremity venous malformations.

PURPOSE: To investigate quantitative changes in MRI signal intensity (SI) and lesion volume that indicate treatment response and correlate these changes with clinical outcomes after percutaneous sclerotherapy (PS) of extremity venous malformations (VMs). METHODS: VMs were segmented manually on pre- and post-treatment T2-weighted MRI using 3D Slicer to assess changes in lesion volume and SI. Clinical outcomes were scored on a 7-point Likert scale according to patient perception of symptom improvement; treatment response (success or failure) was determined accordingly. RESULTS: Eighty-one patients with VMs underwent 125 PS sessions. Treatment success occurred in 77 patients (95 %). Mean (±SD) changes were -7.9 ± 24 cm3 in lesion volume and -123 ± 162 in SI (both, P <.001). Mean reduction in lesion volume was greater in the success group (-9.4 ± 24 cm3) than in the failure group (21 ± 20 cm3) (P =.006). Overall, lesion volume correlated with treatment response (ρ = -0.3, P =.004). On subgroup analysis, volume change correlated with clinical outcomes in children (ρ = -0.3, P =.03), in sodium tetradecyl sulfate-treated lesions (ρ = -0.5, P =.02), and in foot lesions (ρ = -0.6, P =.04). SI change correlated with clinical outcomes in VMs treated in 1 PS session (ρ = -0.3, P =.01) and in bleomycin-treated lesions (ρ = -0.4, P =.04). CONCLUSIONS: Change in lesion volume is a reliable indicator of treatment response. Lesion volume and SI correlate with clinical outcomes in specific subgroups.

Arterial and venous peripheral vascular assessment using wearable electro-resistive morphic sensors.

Peripheral vascular diseases (PVDs) represent a significant burden on global human health and healthcare systems. With continued growth in obesity and diabetes, it is likely that the incidence of these conditions will increase. As many PVDs remain undiagnosed, low-cost and easy to use diagnostic methods are required. This work uses newly developed wearable electro-resistive morphic sensors to assess venous and arterial competence in the lower limbs of 36 healthy subjects. Comparison of this HeMo device was made to currently available benchtop light reflection rheography and photoplethymography devices. Results indicate that HeMo can detect the physiological signals of interest for both chronic venous insufficiency and peripheral arterial disease and all subjects were interpreted as healthy by each system. However, measurement repeatability of HeMo was highlighted as an issue that requires further system development. Furthermore, as HeMo captures changes in a section of limb circumference due to changes in underlying blood movement, rather than at a single point, the recorded signal is typically damped by comparison. This factor should be considered in any future developments.

Implanted blood vessel external support device for the treatment of distal hypoperfusion ischemic syndrome in arteriovenous fistulas and high-frame-rate Vector Flow quality assessment.

INTRODUCTION: Distal hypoperfusion ischemic syndrome (DHIS) is a complication occurring after arteriovenous fistula (AVF) creation. Different surgical alternatives haves been proposed in case of severe DHIS. Aim of the present paper is to present a new technique for DHIS treatment. MATERIAL AND METHODS: Between the 1st of January 2021 and the 31st December 2021 all the patients referred to our center for DHIS grade 2-4 were treated with a new surgical technique. It consists of AVF remodeling using an external nitinol support (VasQ®) to reduce the risk of outflow vein enlargement and DHIS recurrence. To better appreciate the hemodynamic effects of the surgery, a new ultrasound technique called high-frame-rate Vector Flow (HiFR-VF) was used. RESULTS: Seven patients (M:F 1:3; mean age 43 ± 12 years, range 29-65) were included in this study. Central line was never necessary, and technical success was 100% at 12 months. The comparison with historical data demonstrated lower recurrence of symptoms in comparison to simple artery-to-vein redo (p 0.50). The HiFR-VF showed flow with limited turbulent characteristics at the anastomosis site. DISCUSSION AND CONCLUSION: The new technique proposed demonstrated to be safe and effective for treatment of DHIS, preventing symptoms recurrence. Ultrasound examination and HiFR-VF can be considered a valuable method to evaluate complex flows at the levels of vascular anastomosis.

Characterizing Trends in Chronic Superficial Venous Disease Treatment among Medicare Beneficiaries from 2010 to 2018.

This study describes trends in surgical versus endovascular interventions for treatment of chronic superficial venous disease (SVD) in the Medicare population. Medicare Part B data from 2010 to 2018 were obtained. Claims for SVD treatment were identified using Healthcare Common Procedure Coding System codes. Total percentage change in utilization rates and market share was determined for each provider group. Utilization of SVD treatments increased by 58%, mostly owing to growing utilization of endovascular treatments. There was a 66% decrease in surgical treatments. The utilization of ablation and sclerotherapy plateaued in 2016 and decreased in 2017-2018 with the advent of mechanochemical ablation, endovenous microfoam, and cyanoacrylate adhesive, respectively. Analysis showed that endovascular utilization increased across most specialties, with the largest growth seen in cardiology by 427%. Radiologists showed utilization growth of 125%, encompassing 11% of the market share. Endovascular treatment for SVD remains predominant, with increased utilization and concomitant decrease in surgical methods.

A multicenter pilot study evaluating simplified central vein assessment for the diagnosis of multiple sclerosis.

BACKGROUND: The central vein sign (CVS) is a proposed magnetic resonance imaging (MRI) biomarker for multiple sclerosis (MS); the optimal method for abbreviated CVS scoring is not yet established. OBJECTIVE: The aim of this study was to evaluate the performance of a simplified approach to CVS assessment in a multicenter study of patients being evaluated for suspected MS. METHODS: Adults referred for possible MS to 10 sites were recruited. A post-Gd 3D T2*-weighted MRI sequence (FLAIR*) was obtained in each subject. Trained raters at each site identified up to six CVS-positive lesions per FLAIR* scan. Diagnostic performance of CVS was evaluated for a diagnosis of MS which had been confirmed using the 2017 McDonald criteria at thresholds including three positive lesions (Select-3*) and six positive lesions (Select-6*). Inter-rater reliability assessments were performed. RESULTS: Overall, 78 participants were analyzed; 37 (47%) were diagnosed with MS, and 41 (53%) were not. The mean age of participants was 45 (range: 19-64) years, and most were female (n = 55, 71%). The area under the receiver operating characteristic curve (AUROC) for the simplified counting method was 0.83 (95% CI: 0.73-0.93). Select-3* and Select-6* had sensitivity of 81% and 65% and specificity of 68% and 98%, respectively. Inter-rater agreement was 78% for Select-3* and 83% for Select-6*. CONCLUSION: A simplified method for CVS assessment in patients referred for suspected MS demonstrated good diagnostic performance and inter-rater agreement.

First assessment of flow phenomena of acute and chronic thrombosis in the jugular veins using new ultrasound vector-flow imaging.

AIM: First assessment of flow changes in the jugular veins using high resolution ultrasound vector flow. MATERIAL UND METHODS: 15 patients (8 males, 7 females) with an age range of 35 to 82 years (mean age 58.53±12.26 years) were examined by an experienced examiner using high power ultrasound equipment (Resona R9, Mindray) with probe technology (Mindray L9-3U Linear Array transducer, 2.5 to 9.0 MHz). This group was compared with five healthy subjects (mean age 35.4±13.79 years) as a reference. To assess flow changes, the color-coded duplex sonography and the novel vector flow technique were used. The evaluation was performed of vector morphology changes, turbulence, and wall resistance measurements. RESULTS: There were changes after acute and chronic thrombosis in 9 cases, and venous compression in 7 cases. Turbulence was measurable from 0.01 % to 64.44 %, the average turbulence was 19.73±22.06 %. Wall resistance measurement showed values from 0.01 Pa to 3.14 Pa, depending on the age of the thrombosis or compression. The reference veins showed turbulence of 0.94±1.5 % and a mean wall resistance of 0.05±0.05 Pa. There are statistically significant differences between normal and thrombotic or compressed veins in terms of maximum wall stress (p = 0.006) and mean degree of turbulence (p = 0.012), while the difference in mean wall stress is not statistically significant (p = 0.058). CONCLUSION: Despite still existing technical limitations, the combination of V-flow and wall stress measurements in jugular vein changes suggests a high diagnostic potential.

Percutaneous Sclerotherapy of Large Venous Malformations Using Consecutive Polidocanol and Bleomycin Foam: MR Imaging Volumetric and Quality-of-Life Assessment.

PURPOSE: To retrospectively evaluate sclerotherapy using consecutive polidocanol and bleomycin foam (CPBF) for large untreated venous malformations (VMs) and/or those resistant to prior treatment. MATERIALS AND METHODS: This retrospective study included all patients treated with CPBF for untreated VMs larger than 10 mL and/or refractory to treatment between May 2016 and October 2019. Baseline and follow-up VM volumes were measured on fat-suppressed T2-weighted magnetic resonance (MR) imaging. Outcome was evaluated on postprocedural MR imaging volumetry and by a retrospective survey assessing clinical response and adverse events. Imaging response was considered good for volume reduction from 50% to 70% and excellent for volume reduction ≥70%. Symptoms and quality-of-life (QoL) scores were compared before and after CPBF sclerotherapy. RESULTS: Forty-five patients (mean age, 16 years; range, 1-63 years; 25 males) with 57 VMs were analyzed and treated by 80 sclerotherapy. Sixty percent (27 of 45) of patients had undergone prior treatment for VM. Median VM volume was 36.7 mL (interquartile range, 84 mL) on pretherapy MR imaging. Good and excellent results after the last sclerotherapy were achieved in 36% (16 of 45) and 29% (13 of 45) of patients, respectively, corresponding to a decrease of >50% in 60% (34 of 57) of VMs. QoL score increased by at least 3 points, regardless of initial symptoms. Most patients did not desire additional sclerotherapy owing to near complete symptomatic relief, even for patients who did not achieve a good response. Swelling, pain, and motor impairment scores significantly improved after CPBF. Adverse events included fever (44%, 15 of 34) and nausea/vomiting (29%, 10 of 34). CONCLUSIONS: CPBF sclerotherapy represents an effective therapy for large and/or refractory VMs with minimal adverse events.

Assessment of skin and associated soft tissue changes with ultrasonography in chronic venous disease.

OBJECTIVE: Chronic venous disease (CVD) is accompanied by a spectrum of skin changes. The aim of this study was to assess skin changes in CVD in different classes of the classifications such as the Clinical-Etiology-Anatomy-Pathophysiology (CEAP) classification using ultrasound (US). METHODS: This study was conducted from July 2020 to July 2021 after obtaining approval from Institutional Ethical Committee. Patients with chronic venous insufficiency were enrolled after taking informed consent. Assessment of cutaneous layer (CL), subcutaneous layer (SCL), dermo-hypodermal junction (D-HJ), and other significant US findings were noted. RESULTS: Ninety-eight limbs were evaluated. Most common skin finding was dermal edema in 59 (60.2%) legs. Other findings included infiltrates, CL thickening, hyper echogenicity and thickening of SCL, anechoic lacunae, disappearance of D-HJ, and epidermal loss or change in thickness of epidermis. Notably, US detected dermal edema in 15 and infiltrates in five C2 legs (normal on inspection). CONCLUSION: US evaluation of skin changes adds insight to clinical assessment and may reveal skin changes in legs affected with CVD that may appear normal on clinical examination.

A comparison of tablet-based and paper-based venous insufficiency epidemiologic and economic study quality of life/symptom questionnaire for assessment of chronic venous disease.

OBJECTIVE: To comparatively evaluate performances of tablet-based versus paper-based Venous Insufficiency Epidemiologic and Economic Study-Quality of Life/Symptom (VEINES-QOL/Sym) questionnaire. METHODS: We prospectively evaluated 78 consecutive patients who completed tablet-based and paper-based VEINES-QOL/Sym questionnaires and compared their scores, completion time, data entry time, and ease of use. We used Student's t-test and Wilcoxon test for quantitative variables, Bland-Altman test and kappa coefficient for agreement between questionnaires and patients, respectively. Spearman's correlation coefficient was used to assess correlations. RESULTS: Most participants (83.3%) found it easier to use the tablet device. Less time was needed to complete the tablet-based (median, 4.75; IQR, 3-7 min) than the paper-based (median, 8.3; IQR, 6.3-11.3 min) questionnaire (p < .001). Better educated patients took less time to complete paper-based (p = .003) and tablet-based (p = .001) questionnaires and considered the latter easier to use (p = .010). CONCLUSIONS: The tablet-based VEINES-QOL/Sym proved to be an easy-to-use and time-saving tool.

Signal quality assessment of peripheral venous pressure.

Develop a signal quality index (SQI) for the widely available peripheral venous pressure waveform (PVP). We focus on the quality of the cardiac component in PVP. We model PVP by the adaptive non-harmonic model. When the cardiac component in PVP is stronger, the PVP is defined to have a higher quality. This signal quality is quantified by applying the synchrosqueezing transform to decompose the cardiac component out of PVP, and the SQI is defined as a value between 0 and 1. A database collected during the lower body negative pressure experiment is utilized to validate the developed SQI. All signals are labeled into categories of low and high qualities by experts. A support vector machine (SVM) learning model is trained for practical purpose. The developed signal quality index coincide with human experts' labels with the area under the curve 0.95. In a leave-one-subject-out cross validation (LOSOCV), the SQI achieves accuracy 0.89 and F1 0.88, which is consistently higher than other commonly used signal qualities, including entropy, power and mean venous pressure. The trained SVM model trained with SQI, entropy, power and mean venous pressure could achieve an accuracy 0.92 and F1 0.91 under LOSOCV. An exterior validation of SQI achieves accuracy 0.87 and F1 0.92; an exterior validation of the SVM model achieves accuracy 0.95 and F1 0.96. The developed SQI has a convincing potential to help identify high quality PVP segments for further hemodynamic study. This is the first work aiming to quantify the signal quality of the widely applied PVP waveform.

An assessment of microvascular hemodynamics in human macula.

An adequate blood supply to meet the energy demands is essential for any tissue, particularly for high energy demand tissues such as the retina. A critical question is: How is the dynamic match between neuronal demands and blood supply achieved? We present a quantitative assessment of temporal and spatial variations in perfusion in the macular capillary network in 10 healthy human subjects using a non-invasive and label-free imaging technique. The assessment is based on the calculation of the coefficient of variation (CoV) of the perfusion signal from arterioles, venules and capillaries from a sequence of optical coherence tomography angiography images centred on the fovea. Significant heterogeneity of the spatial and temporal variation was found within arterioles, venules and capillary networks. The CoV values of the capillaries and smallest vessels were significantly higher than that in the larger vessels. Our results demonstrate the presence of significant heterogeneity of spatial and temporal variation within each element of the macular microvasculature, particularly in the capillaries and finer vessels. Our findings suggest that the dynamic match between neuronal demands and blood supply is achieved by frequent alteration of local blood flow evidenced by capillary perfusion variations both spatially and temporally in the macular region.

Educating health professionals in ultrasound guided peripheral intravenous cannulation: A systematic review of teaching methods, competence assessment, and patient outcomes.

BACKGROUND: Peripheral intravenous cannula insertion is the most common invasive healthcare procedure, however failure rates remain unacceptably high, particularly in patients with difficult intravascular access. This leads to treatment delays and increased complication risk, causing poorer outcomes among this patient subset. Ultrasonographic guidance reduces these risks and is therefore becoming a competency required of health professionals. However, there is no consensus on how to design teaching sessions to achieve this competency. METHODS: Systematic review was conducted to identify characteristics of effective teaching sessions for current and training health professions to achieve ultrasound guided peripheral intravenous cannulation competency. Secondary outcomes included defining competency and to assess benefits to patients and healthcare systems. Eligibility for inclusion required description of teaching of ultrasound guided peripheral intravenous cannulation to qualified or training health professionals who went on to perform it in human patients or volunteers with reported outcomes or success rates. Studies were excluded if not accessible in full, not peer-reviewed or presented research that had been presented elsewhere previously. Of the 1085 records identified on review of 6 databases, 35 were included for final review based on eligibility criteria. RESULTS: Almost all (97.1%) used mixed modality teaching comprising of didactic and simulation portions, although time allocated varied widely. A median of 5 proctored procedures was required for competency. Competency was independent of previous experience or staff seniority. Mean reported insertion attempts was 1.7, success rate was 82.5% and first-time success rate was 75.5%. All included studies described improvement in their participants or healthcare system including significantly reduced midline insertion rates, central venous catheter insertion rates and associated bacteremia and sepsis, self-reported cannulation difficulty, specialist input, therapy delays and premature catheter failure rates. Further, there was significantly improved procedural confidence, knowledge and competence. CONCLUSION: Simple teaching interventions can lead to competent ultrasound guided peripheral intravenous cannula insertion by novices, resulting in numerous positive outcomes for patients and healthcare systems.

Retrograde sclerotherapy of male varicocele with veno-venous shunts - incidence and management: a single-centre experience.

OBJECTIVES: The aim of our study is to compare the incidence of veno-venous shunts in male varicocele and evaluate the possibility to exclude them with manual compression or/and scrotal ligation in order to carry out the procedure of retrograde sclero-embolization. METHODS: In our retrospective study, all patients undergone retrograde sclerotherapy for varicocele in our Interventional Radiology Unit in the last four years were evaluated. Collaterals toward other venous shunts were identified and how many and which patients would be able to complete the procedure safely were considered. RESULTS: Of the 91 patients, as many as 22 (i.e., 24.17%) patients presented anatomical variants, consisting on shunting into left iliac vein (9 [9.89%]), lumbar left veins (3 [3.29%]), right iliac vein (1 [1.09%]), both iliac veins (1 [1.09%]), left femoral vein (1 [1.09%]) or a more proximal portion of the ISV itself without shunting (3 [3.29%]). Patients with duplication could benefit from a more distal injection in order to prevent back-flow; of the 19 left, nine successfully underwent sclerotherapy with manual compression or/and scrotal ligation, whereas in 10 flow through the collaterals could not be interrupted and patients were demanded for surgery. CONCLUSIONS: Many patients with abnormal communications between the internal spermatic vein and the iliac veins (that is, shunts towards the iliac veins) may as well undergo retrograde sclerotherapy safely if compression/ligation is applied. ADVANCES IN KNOWLEDGE: No large previous study highlighted the impact of veno-venous shunts in technical feasibility of retrograde sclerotherapy of varicocele.

Intraprocedural cortisol testing improves adrenal vein cannulation success and diagnostic accuracy in assessment of primary aldosteronism, in a medium throughput centre.

Primary aldosteronism is the most common cause of secondary hypertension. Identifying individuals who have unilateral secretion from aldosterone secreting adenomas allows adrenalectomy. Surgical treatment when feasible may be superior to medical management with improved cardiovascular outcomes and reduced medication dependence. Adrenal vein sampling (AVS) is required to biochemically lateralise aldosterone secretion prior to adrenalectomy. However, diagnostic success of AVS is variable and can be poor even at tertiary centres; failure is largely due to unsuccessful adrenal vein cannulation. Intra-procedural rapid semiquantitative cortisol testing (RCT) identifies correct catheter placement in real time. We compared diagnostic success rates of AVS before and after the introduction of intraprocedural cortisol testing at the Royal Adelaide Hospital-a medium throughput tertiary centre (average 6.2 procedures a year over the last 8 years). We observed an increase in success rate from 63% to 94%. Intraprocedural cortisol testing also led to a net financial saving of ~$100 AUD per procedure. RCT is likely to be cost effective if pre-RCT success rate is less than 78%. Procedure time and number of samples collected, however, were increased with RCT. This suggests that intraprocedural cortisol testing will improve success in low to medium throughput centres and may make AVS feasible in less specialised centres.

Lesion size and shape in central vein sign assessment for multiple sclerosis diagnosis: An in vivo and postmortem MRI study.

BACKGROUND: The "central vein sign" (CVS), a linear hypointensity on T2*-weighted imaging corresponding to a central vein/venule, is associated with multiple sclerosis (MS) lesions. The effect of lesion-size exclusion criteria on MS diagnostic accuracy has not been extensively studied. OBJECTIVE: Investigate the optimal lesion-size exclusion criteria for CVS use in MS diagnosis. METHODS: Cross-sectional study of 163 MS and 51 non-MS, and radiological/histopathological correlation of 5 MS and 1 control autopsy cases. The effects of lesion-size exclusion on MS diagnosis using the CVS, and intralesional vein detection on histopathology were evaluated. RESULTS: CVS+ lesions were larger compared to CVS- lesions, with effect modification by MS diagnosis (mean difference +7.7 mm3, p = 0.004). CVS percentage-based criteria with no lesion-size exclusion showed the highest diagnostic accuracy in differentiating MS cases. However, a simple count of three or more CVS+ lesions greater than 3.5 mm is highly accurate and can be rapidly implemented (sensitivity 93%; specificity 88%). On magnetic resonance imaging (MRI)-histopathological correlation, the CVS had high specificity for identifying intralesional veins (0/7 false positives). CONCLUSION: Lesion-size measures add important information when using CVS+ lesion counts for MS diagnosis. The CVS is a specific biomarker corresponding to intralesional veins on histopathology.

Real-Time Assessment of Free Flap Capillary Circulation Using Videocapillaroscopy.

BACKGROUND: Free tissue transfer is a common method of reconstruction for various surgical defects. Many clinical assessment methods, including flap color monitoring and capillary refill time measurements, are commonly used to assess the microcirculation of the flap, yet there is no objective tool available that can clear real-time visualization of the flap microcirculation. The purpose of this study was to use a novel videocapillaroscope to evaluate the circulation changes on free flap skin surfaces while purposely clamping pedicle vessels. METHODS: Ten patients who underwent free flap transfer for head and neck cancer from November of 2019 to June of 2020 were included in the study. Videocapillaroscopic observation was performed after flap elevation, and changes in the flap skin capillary circulation with artery-controlled and vein-controlled clamping were recorded. RESULTS: Average total surgery time was 517.91 minutes (SD, 73.3 minutes), average flap elevation time was 102.9 minutes (SD, 18.3 minutes). When the pedicle artery or vein was purposely clamped, the movement of red blood cells in blood vessels stopped; when clamps were removed after 60 seconds, the restoration of red blood cell movements was rapidly observed. When the pedicle artery was clamped, the number of visualizable blood vessels decreased and flap color became relatively white. When the pedicle vein was clamped, the number of visualizable blood vessels increased, and flap color tone had a tendency toward red. CONCLUSION: Novel videocapillaroscopy can be utilized for objective real-time flap monitoring by directly visualizing flap skin capillary microcirculation. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, V.

Vein pattern recognition based on RGB images using Monte Carlo simulation and ridge tracking.

In forensic investigations, images of evidence can often be obtained from crimes such as child pornography and masked violent riots. However, identifying criminals is usually very difficult and sometimes impossible because these images usually contain skin of body parts, while their faces and other commonly used biometrics are unavailable. Vein patterns are a potential biometric to solve this problem. Traditional systems use near-infrared (NIR) imaging technologies to obtain vein patterns, which cannot be applied to forensic analysis since only RGB images are available. However, veins are unobservable in RGB images. In this paper, a comprehensive scheme including a vein uncovering algorithm, a vein extraction algorithm, and a vein pattern matching algorithm is presented. Based on the Monte Carlo (MC) simulation of light transmission in a skin optical model, physical parameters corresponding to different skin colors are obtained, and vein patterns are uncovered from the parameter distribution images. After preprocessing with cubic convolution and Gabor filtering, vein lines are extracted based on ridge tracking. Local gradient orientation and the geometric direction of veins are utilized to guarantee the correct tracking direction. Hessian-based Frangi filters are adopted to locate potential veins. In the matching step, effective minutiae are extracted to represent the topology of vein patterns. A modified coherent point drift (CPD) algorithm is proposed utilizing coordinates, Gabor energy values, and curvatures of minutiae to match vein patterns. Comprehensive experiments were carried out to evaluate the proposed three algorithms. Experimental results show the superiority of the proposed algorithms to various state-of-the-art methods.

A review of the incidence, outcome, and management of venous stent migration.

BACKGROUND: Percutaneous endovenous stenting has emerged during the past decade as the primary method of treating symptomatic venous outflow obstruction. A recognized complication of venous stenting is stent migration. The aim of the present systematic review was to identify the number of cases of stent migration in reported studies to recognize the risk factors that might be associated with this complication and the outcomes following migration. METHODS: A review was conducted in accordance with the MOOSE (meta-analyses of observational studies in epidemiology) and PRIMSA (preferred reporting items for systematic review and meta-analysis) guidelines and registered in the PROSPERO. MEDLINE, EMBASE, and PubMed databases. Key references were searched using specified keywords. All relevant data for the primary procedure and subsequent presentation with stent migration were retrieved. The data were assessed as too low in quality to allow for statistical analysis. RESULTS: Between 1994 and 2020, 31 studies were identified, including 29 case reports and 2 case series, providing data for 54 events of venous stent migration with some data provided regarding the stent used for 47 of the events. The mean age of the 52 patients with stent migration was 50 years (range, 19-88 years) and 30 were men (57.6%). The stents for most of the reported cases were ≤60 mm in length (38 of 46; 82.6%). Only three of the reports were of stents >14 mm in diameter (3 of 47; 3.6%). None of the studies had reported migration of stents >100 mm long. In 85% of the migrated stent events, retrieval was attempted, with 65.2% via an endovascular approach. The immediate outcome was satisfactory for 100% of the reported attempts, whether by an endovascular or open surgical approach. CONCLUSIONS: The findings from our literature review suggest that the risk of migration is rare but might be underreported. Most of reported cases had occurred with shorter and smaller diameter stents. The paucity of reported data and the short-term follow-up provided suggest that more formal data collection would provide a truer reflection of the incidence. However, clear strategies to avoid migration should be followed to prevent this complication from occurring.

Antecubital Vein Cannula Position Impacts Assessment of Forearm Glucose Uptake During an Oral Glucose Challenge in Healthy Volunteers.

INTRODUCTION: Skeletal muscle is a major site for whole-body glucose disposal, and determination of skeletal muscle glucose uptake is an important metabolic measurement, particularly in research focussed on interventions that impact muscle insulin sensitivity. Calculating arterial-venous difference in blood glucose can be used as an indirect measure for assessing glucose uptake. However, the possibility of multiple tissues contributing to the composition of venous blood, and the differential in glucose uptake kinetics between tissue types, suggests that sampling from different vein sites could influence the estimation of glucose uptake. This study aimed to determine the impact of venous cannula position on calculated forearm glucose uptake following an oral glucose challenge in resting and post-exercise states. MATERIALS AND METHODS: In 9 young, lean, males, the impact of sampling blood from two antecubital vein positions; the perforating vein ('perforating' visit) and, at the bifurcation of superficial and perforating veins ('bifurcation' visit), was assessed. Brachial artery blood flow and arterialised-venous and venous blood glucose concentrations were measured in 3 physiological states; resting-fasted, resting-fed, and fed following intermittent forearm muscle contraction (fed-exercise). RESULTS: Following glucose ingestion, forearm glucose uptake area under the curve was greater for the 'perforating' than for the 'bifurcation' visit in the resting-fed (5.92±1.56 vs. 3.69±1.35 mmol/60 min, P<0.01) and fed-exercise (17.38±7.73 vs. 11.40±7.31 mmol/75 min, P<0.05) states. DISCUSSION: Antecubital vein cannula position impacts calculated postprandial forearm glucose uptake. These findings have implications for longitudinal intervention studies where serial determination of forearm glucose uptake is required.