Adapting a Dialysis Service for Delivery of Percutaneous Arteriovenous Fistulas.

The percutaneous arteriovenous fistula (pAVF) is an exciting and novel addition to the vascular access options available to patients with end-stage kidney disease who require dialysis. Early clinical results have been promising, with high rates of maturation and low rates of reintervention. To successfully adapt an existing hemodialysis service to include the provision of pAVF formation, it is essential to identify and align the interests of key clinical and nonclinical stakeholders. Only through strong collaboration can the service be supported. The authors provide a comprehensive overview of the planning fundamentals required, including the referral pathway, screening and clinical assessment, and practical procedural elements and considerations, as well as follow-up requirements such as cannulation, fistula surveillance, and maintenance. Key staffing requirements are highlighted, including those pertaining to vascular US screening and dialysis nurse training. A broad and structured planning approach ensures that the entire network of key stakeholder interests is included and provides a strong foundation for a compelling business plan to attract the necessary funding and managerial support for the service. The authors present a systematic framework of the essential considerations necessary to facilitate the planning, funding, and ultimately delivery of a successful pAVF service. Online supplemental material is available for this article. ©RSNA, 2022.

A multicenter randomized controlled trial indicates that paclitaxel-coated balloons provide no benefit for arteriovenous fistulas.

The role of paclitaxel-coated balloons has been established in the coronary and peripheral arterial circulations with recent interest in the use of paclitaxel-coated balloons to improve patency rates following angioplasty of arteriovenous fistulas. To assess the efficacy of paclitaxel-coated angioplasty balloons to prolong the survival time of target lesion primary patency in arteriovenous fistulas, we designed an investigator-led multi-center randomized controlled trial with follow up time variable for a minimum of one year. Patients with an arteriovenous fistula who were undergoing an angioplasty for a clinical indication were included but patients with one or more lesions outside the treatment segment were excluded. Following successful treatment with a high-pressure balloon, 212 patients were randomized. In the intervention arm, the second component was insertion of a paclitaxel-coated balloon. In the control arm, an identical procedure was followed, but using a standard balloon. The primary endpoint was time to loss of clinically driven target lesion primary patency. Primary analysis showed no significant evidence for a difference in time to end of target lesion primary patency between groups: hazard ratio 1.18 with a 95% confidence interval of 0.78 to 1.79. There were no significant differences for any secondary outcomes, including patency outcomes and adverse events. Thus, our study demonstrated no evidence that paclitaxel-coated balloons provide benefit, following standard care high-pressure balloon angioplasty, in the treatment of arteriovenous fistulas. Hence, in view of the benefit suggested by other trials, the role of paclitaxel-coated angioplasty balloons remains uncertain.

Paclitaxel-Coated Balloons for the Treatment of Symptomatic Central Venous Stenosis in Vascular Access: Results From a European, Multicenter, Single-Arm Retrospective Analysis.

INTRODUCTION: This was a European, multicenter, investigator-initiated and run, single-arm retrospective analysis to assess the safety and the clinical benefit of the use of paclitaxel-coated balloon (PCB) for the treatment of symptomatic central venous stenosis (CVS). MATERIALS AND METHODS: Eleven centers from 7 countries across Europe, submitted 86 cases performed during the period between October 2015 and June 2018. Minimum follow-up was 6 months. Patient baseline demographics and procedural details were collected. Mean age was 62.6 years (SD 15.2 years). Median vascular access age was 3.0 years (IQR 1.2-4.8 years). A total of 55 were arteriovenous fistulas (64%) the rest arteriovenous grafts (31/86, 36%). Vessels treated were 43 subclavian veins, 42 brachiocephalic veins and 1 superior vena cava. Median drug-coated balloon diameter was 10 mm (IQR 8-12 mm). Primary outcome measures were clinically assessed intervention-free period (IFP) of the treated segment at 6 months and procedure-related minor and major complications. Secondary outcome measures included access circuit survival, patient survival, and the investigation of independent factors that influence the IFP. RESULTS: IFP was 62.7% at 6 months. Median patient follow-up time was 1.0 year (IQR 0.5-2.2 years). There was 1 minor complication (1/86; 1.2%) and no major complications. Access circuit survival was 87.7% at 6 months. Patient survival was 79.7% at 2 years according to Kaplan-Meier survival analysis. Higher balloon diameters significantly favored IFP [HR 0.71 (0.55-0.92), p=0.006; 5-7 mm group vs 8-12 mm group, p=0.025]. CONCLUSION: In this analysis, use of PCBs for the treatment of symptomatic CVS was safe. Efficacy was comparable to previous trials. Increased balloon size had a significant effect on patency rates.

Reducing the Number of Measurements in Liver Point Shear-Wave Elastography: Factors that Influence the Number and Reliability of Measurements in Assessment of Liver Fibrosis in Clinical Practice.

Purpose To identify the minimum number of measurements required for the noninvasive assessment of liver fibrosis by using point shear-wave elastography (pSWE) and determine whether the use of a reliability indicator such as interquartile range [IQR]-to-median ratio will affect diagnostic performance. Materials and Methods Ten liver shear-wave velocity (SWV) measurements by pSWE were obtained in 232 participants. Interclass correlation coefficients (ICC) between the median of the first two through the first nine measurements and all 10 measurements were calculated; the minimum number of measurements with ICC greater than 0.95 versus all 10 measurements was determined. The diagnostic performance of the minimum number of measurements and 10 measurements in identifying significant (Ishak stage, ≥3) and severe fibrosis or cirrhosis (Ishak stage, ≥5) was compared by using areas under the receiver operating characteristic curve. These were compared between measurements that demonstrated higher or lower reliability (IQR-to-median ratio of ≤ 30% and IQR-to-median ratio of > 30%, respectively). Results Compared with 10 measurements, a minimum of six SWV measurements was required. The overall area under the curve for diagnosing significant (areas under the receiver operating characteristic curve, 0.828 vs 0.839; P = .487) and severe fibrosis or cirrhosis (0.953 vs 0.969, respectively; P = .145) did not differ according to number of measurements (six vs 10); a median of six measurements resulted in only limited disagreement (nine of 232 [3.9%]) versus histologic evaluation. When using 10 measurements, higher reliability measurements showed a lower percentage of discordance between pSWE and significant fibrosis and severe fibrosis or cirrhosis (22 [14.7%] and three [2.0%] of 150 cases, respectively) compared with lower reliability measurements (26 [31.7%] and eight [9.8%] of 82 cases, respectively). Significant fibrosis was an independent predictor for lower reliability (hazard ratio, 2.22; P < .020). Conclusion A limited number of SWV measurements (median six vs median 10) were required for the assessment of liver fibrosis by using pSWE. The number of measurements had less influence on the diagnostic accuracy compared with lower reliability measurements. © RSNA, 2018 Online supplemental material is available for this article.

Increased prevalence of renal cysts in patients with sickle cell disease.

BACKGROUND: Early detection and interventions have enabled patients with sickle cell disease (SCD) to live well into adulthood. Consequently, the chronicity of SCD allows for the insidious manifestation of multisystem complications, including renal damage. Cystic renal lesions are commonly incidentally discovered on ultrasound and computerised tomography (CT) imaging of the abdomen. Most are benign simple cysts, however, difficulties may be encountered if infection, rupture, haemorrhage or cancerous changes develop. We aimed to determine whether patients with SCD have a higher prevalence of simple renal cysts compared to non-SCD individuals. METHODS: Data for a group of 223 patients with SCD who had undergone an ultrasound and/or CT imaging of the abdomen were extracted for comparison with 180 control patients (haemoglobin genotype unknown), matched for age and ethnicity. Scans were evaluated for 198 SCD patients and 180 controls. RESULTS: Renal cysts were found in 58% of the SCD group and 20% of the controls (OR 5.4 (CI 2.6-11.0), RR 2.8 (CI 1.9-4.2)). Bilateral renal cysts were found in 28% of the SCD participants in comparison with 5% of the control group. In those who had one or more cysts identified, the average number of cysts was 3.76 for the SCD group and 1.94 for the controls. Men with SCD were more likely to develop cysts than women (66% vs 53%), as were men without SCD (22% vs 17%). CONCLUSIONS: Simple renal cysts occur more frequently, are more abundant and develop at a younger age in patients with SCD than ethnically-matched controls. Further study of the mechanism underlying cyst formation may shed light on both sickle cell nephropathy and other cystic renal diseases.

Contrast-enhanced ultrasound in the evaluation of focal testicular complications secondary to epididymitis.

OBJECTIVE: The purpose of this study is to determine the effectiveness of contrast-enhanced ultrasound in evaluating incidental focal testicular lesions in epididymitis. MATERIALS AND METHODS: Intratesticular lesions ipsilateral to epididymitis were subject to B-mode color Doppler ultrasound and contrast-enhanced ultrasound, with their appearances reviewed in consensus. Final interpretation was by histologic analysis or follow-up ultrasound. RESULTS: Over 28 months, 16 focal testicular lesions (median lesion size, 24 mm; range, 14-48 mm) in 14 patients (median age, 49 years; range, 18-81 years) were examined. Lesions were oval (n = 14), wedge shaped (n = 1), or involved the entire testis (n = 1). Lesions were isoechoic (n = 1), hypoechoic (n = 4), or of mixed echogenicity (n = 11). Color Doppler ultrasound flow was not clearly depicted in 13 lesions but was present in three lesions, with contrast-enhanced ultrasound concordant with color Doppler ultrasound, showing unequivocal absence of vascularity and increased flow, respectively. In the avascular lesions, rim enhancement (n = 6), vascular projections (n = 4), and irregular (n = 10) and smooth (n = 2) borders were documented. The observers identified infarction (n = 9), abscess (n = 4), orchitis (n = 1), and tumor (n = 2). Histologic examination (seven lesions in five patients) confirmed infarction, abscess formation, and seminoma; follow-up ultrasound confirmed resolution for eight patients. CONCLUSION: Contrast-enhanced ultrasound is a useful adjuvant to color Doppler ultrasound examination of a focal lesion in the testis ipsilateral to epididymitis to improve the characterization of nonvascularized tissue.

COVID-19 and Delayed Cerebral Ischemia-More in Common Than First Meets the Eye.

Since the arrival of the global COVID-19 pandemic scientists around the world have been working to understand the pathological mechanisms resulting from infection. There has gradually been an understanding that COVID-19 triggers a widespread endotheliopathy and that this can result in a widespread thrombosis and in particular a microthrombosis. The mechanisms involved in the microthrombosis are not confined to infection and there is evidence that patients with aneurysmal sub-arachnoid haemorrhage (SAH) also suffer from an endotheliopathy and microthrombosis. In this article we attempt to shed light on similarities in the underlying processes involved in both diseases and suggest potential treatment options.

A UK Expert Consensus Approach for Managing Symptomatic Arteriovenous Fistula (AVF) Stenosis in Haemodialysis Patients.

PURPOSE: Stenoses in mature arteriovenous fistulas (AVFs) are common and can negatively impact on the quality of haemodialysis, the longevity of the AVF and lead to debilitating symptoms. Multiple treatment options exist; however, management can vary between different centres. We aimed to establish multidisciplinary consensus on the optimal stepwise application of interventions based on evidence and consensus. METHODS: A modified Delphi process was conducted with 13 participants from hospitals across the UK, all of whom have high-volume dialysis access practice. RESULTS: The usual intervention to rectify de novo stenoses of mature AVFs is fistuloplasty, although surgery for inflow segment stenoses is also clinically acceptable. Appropriate first-line interventions include plain old balloon angioplasty or high-pressure balloon angioplasty; if these fail during the fistuloplasty, consider upsizing the balloon, prolonged balloon inflation or using alternative interventions, such as cutting or scoring balloons and ultra-high-pressure balloons. Alternative or subsequent interventions vary by anatomical site and may require additional multidisciplinary team input. For a stenoses recurring between 3 and 12 months, it is appropriate to consider interventions used de novo, but with a lower threshold for using drug-coated balloons (DCBs) in all regions and for using stent grafts in all regions but inflow segment. Recurrence after 12 months should be treated as a de novo lesion, with DCBs considered if they have been used successfully during previous interventions. CONCLUSIONS: These recommendations aim to provide a practical guide to multidisciplinary teams in order to optimise the use of multiple interventions for rectifying AVF stenoses and provide unified evidence-based practice guidelines.

Vascularity of Intra-testicular Lesions: Inter-observer Variation in the Assessment of Non-neoplastic Versus Neoplastic Abnormalities After Vascular Enhancement With Contrast-Enhanced Ultrasound.

The aim of this study is to assess the additional benefit of contrast-enhanced ultrasound (CEUS) over conventional ultrasonography (US) in identifying intra-testicular abnormalities among observers of different experiences. In this study, 91 focal testicular lesions (46 neoplastic, 45 non-neoplastic) imaged with gray-scale US/Doppler US and CEUS were classified using a 5-point scale. Three experienced and four inexperienced observers rated each lesion using gray-scale/color Doppler US alone and then with the addition of CEUS. Improved diagnostic specificity and accuracy with the addition of CEUS was observed for both experienced (specificity: 71.1% vs. 59.3%, p = 0.005; accuracy: 83.5% vs. 76.9%, p = 0.003) and inexperienced observers (specificity: 75.6% vs. 51.7%, p = 0.005; accuracy: 80.2% vs. 72.0%, p < 0.001). Significant inter-observer variability between the experienced and inexperienced observers when assessing conventional US alone was eliminated with the addition of CEUS. CEUS improves diagnostic accuracy of focal intra-testicular lesions for both experienced and inexperienced observers and reduces inter-observer variability in inexperienced operators.

Preoperative liver shrinking diet for bariatric surgery may impact wound healing: a randomized controlled trial.

BACKGROUND: In bariatric surgery, preoperative very low-calorie diets (VLCD) may better meet the technical demands of surgery by shrinking the liver. However, diets may affect tissue healing and influence bowel anastomosis in an as-yet-undefined manner. OBJECTIVE: This randomized controlled trial aimed to examine the effect on collagen deposition in wounds in patients on a 4-week VLCD before laparoscopic gastric bypass. SETTING: University hospital. METHODS: The trial was undertaken in patients undergoing laparoscopic Roux-en-Y gastric bypass, with a control group (n = 10) on normal diet and an intervention group (n = 10) on VLCD (800 kcal) for 4 weeks. The primary outcome measured was expression of collagen I and III in skin wounds, with biopsies taken before and after the diet and 7 days postoperatively as a surrogate of anastomotic healing. Secondary outcome measures included liver volume and fibrosis score, body composition, operating time, blood loss, hospital stay, and complications. RESULTS: Patients in both groups were similar in age, sex, body mass index (53.4 versus 52.8 kg/m2), co-morbidities, liver volume, and body composition. Expression of mature collagen type I was significantly decreased in diet patients compared with controls after 4 weeks of diet and 7 days after surgery. This was significant decrease in liver volume (23% versus 2%, P = .03) but no difference in operating times (129 versus 139 min, P = .16), blood loss, length of stay, or incidence of complications. CONCLUSIONS: Preoperative diets shrink liver volume and decrease expression of mature collagen in wounds after surgery. Whether the latter has a detrimental effect on clinical outcomes requires further evaluation.

Improving the practice of inferior vena cava filter retrieval: a quality improvement intervention and audit outcomes.

OBJECTIVE: To review inferior vena cava (IVC) filter retrieval practice at our institution, the Royal London Hospital, and measure changes following a quality improvement intervention. IVC filters are a preventive treatment for pulmonary embolism when anticoagulation is ineffective/contraindicated. Unless permanent filtration is required, all filters should undergo attempted retrieval within manufacturer's recommendations with a success rate of ≥80 %. METHODS: Retrospective audit of filters inserted between 2011 and 2014, followed by a quality improvement intervention and a second audit between 2015 and 2017. Clinical-radiological data were analysed using the Picture Archiving and Communication System and electronic patient records. RESULTS: During the first audit, filter retrieval was attempted in 92% of cases, of which 82% underwent the procedure within manufacturer's recommendations and 86% were successful. During the second audit, an improvement across indicators was seen. Retrieval increased by 3% and was attempted in 95% of cases (92% of which were within manufacturer's guidelines). Rate of retrievals within manufacturer's guidelines increased by 10%. Filter retrieval success rate increased by 11% - to 97%. CONCLUSIONS: IVC filter retrieval practice at a single institution can be improved by implementing a simple audit intervention. ADVANCES IN KNOWLEDGE: Filter retrieval practice has clinical and medicolegal implications. A simple quality intervention can substantially improve overall practice.

Broken Wings: First Reported Cases of Fractured Angel® Catheters, a Temporary Combined Femoral Venous Catheter and Retrievable IVC Filter Device.

There has been increasing use of a novel combined femoral venous sheath, catheter and retrievable self-expanding and collapsible diamond-shaped IVC filter (Angel® Catheter, BiO2 Medical), in severely injured patients who cannot receive anticoagulation. As the filter is not detached from the catheter/sheath, it should be easily retrieved. Outcomes included in large registries demonstrate a high safety profile and a 100% retrieval rate. However, at our institution-a Level 1 major UK trauma centre with 4 years of substantial experience in using this device-we've encountered three cases of device fracture and subsequent complicated retrieval dating from Dec 2016 to March 2017. To the best of the authors' knowledge, we describe the first documented case series of fractured Angel® Catheters and their retrieval.

Appearances of von meyenburg complex on cross sectional imaging.

The von Meyenburg complex (VMC) is an uncommon congenital malformation and is characterized by benign bile duct hamartomas. These are usually discovered incidentally and may represent a diagnostic dilemma when liver metastases are suspected. MRI of VMC shows distinct imaging characteristics, but reporting of lesional contrast enhancement has been inconsistent, whilst microbubble contrast enhanced ultrasound provides 'real-time' evaluation of soft tissue vascularity. Given the diagnostic uncertainty over imaging in VMC, biopsy is often recommended as the definitive diagnosis. We report a biopsy proven case of VMC on a background of primary colonic malignancy investigated with ultrasound, contrast enhanced ultrasound, computed tomography CT, and magnetic resonance imaging MRI, and review the key imaging features.