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Arteriovenous fistula (AVF) complications are classified based on fistula outcomes. This review aims to update colour Doppler (CD) and pulse wave Doppler (PWD) roles in managing early and late complications of the native and prosthetic AVF. Vascular access (VA) failure occurs because inflow or outflow stenosis activates Wirchow’s triad inducing thrombosis. Therefore, the diagnosis of the tributary artery and outgoing vein stenosis will be the first topic considered. Post-implantation complications occur from the inability to achieve AVF maturation and dialysis suitability due to inflow/outflow stenosis. Late stenosis is usually a sequence of early defects repaired to maintain patency. Less frequently, in the mature AVF or graft, complications are acquired ‘de novo’. They derive either from incorrect management of vascular access (haematoma, pseudoaneurysm, prosthesis infection) or wall pathologies (aneurysm, myxoid valve degeneration, kinking, coiling, abnormal dilation from defects of elastic structures). High-resolution transducers (10–20 MHz) allow the characterization of the wall damage, haemodynamic dysfunctions, early and late complications even if phlebography remains the gold standard for the diagnosis for its sensitivity and specificity.

Central venous cannulation is a frequent need for urgent or scheduled hemodialysis. Many studies confirmed the pivotal role of ultrasound in this procedure. Vascular access guidelines strongly recommend ultrasound guidance. Its usefulness has been demonstrated not only in reducing complications of venipuncture but more recently for the evaluation of central venous catheter (CVC) placement and real-time check for possible complications. The use of ultrasound requires a precise technique for the correct handling of the probe and the needle movement. Different approaches as the out-of-plane, in-plane, and oblique methods are available, enabling the most appropriate for the individual case. Although the learning curve for CVC ultrasound placement is usually fast, formal training and certification for beginners are strongly recommended.

Patients undergoing haemodialytic treatment have a lower quality of life than the general population because of several factors. Their wellbeing can be assessed through a clinical evaluation or through the subjective point of view of the patients themselves: the perceived Health-Related Quality of Life (HRQoL) is an index calculated on the basis of the patients' own perspective. A well-functioning vascular access (VA) and the absence of complications are certainly associated with better health in patients on dialysis but unfortunately VA-related perceived HRQoL has so far been a subject of little interesting literature, even though the choice of the most appropriate access in the individual patient is today increasingly articulate and difficult. Information about subjective perception of health is typically collected through generic or specific questionnaires. The most used reproducible questionnaires available are SF-36, EuroQoL5D, SONG-HD, WHOQoL-BREF, VAQ, although not all of them have been used for a targeted assessment of the issues concerning HRQoL and VA function. This review confirms that the VAQ questionnaire is currently the simplest and most reliable tool to assess patient satisfaction with their VA.

Reports of stuck hemodialysis catheters have been on the rise in recent years. Aim of this work is to report how this complication has been managed and the relative outcomes in a multicente Italian survey.Since 2012, the Italian Society of Nephrology (SIN) Project Group of Vascular Access has collected data among nephrologists on this complication. Data regarding 72 cases of stuck tunnelled central venous catheter (tCVC) in 72 patients were retrieved thanks to this survey.In 11 patients (15%) the stuck catheter was directly buried or left in place. Sixty-one cases were managed through advanced removal techniques. Among these, 47 (77%) stuck tunnelled central venous catheters were successfully removed, while 14 (23%) failed to be withdrawn. Considering removed tCVCs, the use of endoluminal balloon dilatation alone or in combination with other tools showed a percentage of success of 88%. The removal procedure involved numerous specialists. Some complications occurred, such as breakage of the line or bleeding, and two cases of haemopericardium during an advanced procedure.The survey shows how the stuck catheter complication was managed in different ways, with conflicting results. When utilized, endoluminal balloon dilatation proved to be the most effective and most often utilized technique, while some cases had suboptimal management or failure. This underlines how delicate the procedure is, and the need for both precise knowledge of this complication and timely organization of removal attempts.

Background: Metformin-associated lactic acidosis (MALA) is a severe complication of drug administration with significant morbidity and mortality. So far no study in large population areas have examined the incidence, clinical profile and outcome of acute kidney injury (AKI)-MALA patients admitted in intensive care units (ICUs) and treated by renal replacement therapy (MALA-RRT). Methods: Retrospective analysis over a 6-year period (2010-2015) in Piedmont and Aosta Valley regions (5,305,940 inhabitants, 141,174 diabetics treated with metformin) of all MALA-RRT cases. Results: One hundred and seventeen cases of AKI-MALA-RRT were observed (12.04/100,000 metformin treated diabetics, 1.45% of all RRT-ICU patients). Survival rate was 78.3%. The average duration of RRT was 4.0 days at mean dialysis effluent of 977 mL/kg/day. At admission most patients were dehydrated, and experienced shock and oliguria. Conclusion: Our data showed that MALA-RRT is a common complication, needing more prevention. Adopted policy of early, extended, continuous and high efficiency dialysis could contribute to an observed high survival rate. Video Journal Club “Cappuccino with Claudio Ronco” at http://www.karger.com/?doi=471917.

To the Editor: The excellent paper by De Vriese et al in a recent issue of Kidney International on folate for cardiovascular disease in uremia largely underestimates the risk of folate overdose1. The suggestion that "high doses of folic acid are well tolerated and safe" takes root from four studies with 4 to 8 weeks and 12 to 17 months of follow-up. From one 10-year-old reference is the message that "routine measurement of vitamin B12 concentrations and inclusion of vitamin B12 in the supplements should completely eliminate ... the risk of masking vitamin B12 deficiency." Because close surveillance is suggested to look for adverse effects produced from folate fortification of food in the general population, which increases serum folate from 10.8 to 19.0 ng/mL2, how can we forecast that in uremic people values as high as 200 to 400 ng/mL are safe over a long time? Treatment for hyperhomocysteinemia in uremic patients results in normal vitamin B12 coupled with very high folate concentrations (Fig. 1). Could such an unbalance derange the biochemical basis of folate/vitamin B12 interrelationship producing a "relative" vitamin B12 deficiency?