"Lock therapy": da utopia a realtà

Negli ultimi anni la presenza di cateteri venosi centrali permanenti (CVCp), quale accesso vascolare per l'emodialisi, rappresenta un'evenienza sempre più comune. Il problema principale del CVCp è rappresentato dal biofilm che a sua volta determina un aumento di rischio d'infezione e di trombosi. Recentemente è stata posta particolare attenzione alla soluzione di chiusura "lock" del CVCp. L'eparina andrebbe abbandonata poiché induce più rapidamente lo sviluppo di biofilm ed espone il paziente a rischio di sanguinamento dovuto all'overspil-ling. La soluzione citrato (3.8%) determina attualmente il migliore rapporto rischio/beneficio sul funzionamento del CVC, ma non offre vantaggi sulla riduzione delle infezioni. Le soluzioni con citrato ipertonico (46.7%) e con antibiotico (AML) andrebbero riservate solo su pazienti con elevata incidenza di episodi d'infezione e nei quali non è possibile una sostituzione del CVCp. Le AML andrebbero usate per periodi brevi per il rischio di sviluppo di resistenze. Per l'etanolo è necessario attendere l'esito di importanti trial. Nella corretta gestione del CVC, qualunque "lock" sia utilizzato, va sempre ricordato il continuo addestramento del personale e l'applicazione delle misure igieniche universali

Uso degli anticoagulanti orali per la prevenzione della trombosi dei cateteri venosi centrali per emodialisi

Central venous catheters (CVCs) are fundamental in the management of hemodialysis. Despite major efforts to provide arteriovenous access, their use is increasing in dialysis units worldwide. The presence of a catheter inside a vein increases the risk of thrombosis, both within the catheter and in the vein. Thrombosis is a serious complication because it can lead to inefficient dialysis, alter the venous circulation, and facilitate infections. In this article, questions regarding anticoagulant treatment in dialysis patients with CVCs are explored and specific suggestions offered for clinical practice, based on the evidence available and the personal experience of the authors. Should CVC-induced thrombosis be treated? The duration, site and extension of the thrombotic complication should be assessed. If thrombosis is recent and symptomatic, heparin treatment followed by oral anticoagulant therapy is suggested. Is oral anticoagulant therapy useful for primary prevention of thrombosis, both within the CVC and the vein where the catheter is inserted? The available evidence favoring the use of oral anticoagulant therapy is not entirely convincing. At any rate, before such treatment is started the balance between the antithrombotic efficacy and the possible side effects should be carefully weighed. Is oral anticoagulant therapy useful for secondary prevention of CVC thrombosis? If a permanent CVC is in place and its position is correct and the blood flow < 250 mL/min, we recommend - before replacing the CVC - thrombolytic treatment followed by oral anticoagulants, aiming at an INR target between 2 and 3. Are the side effects of oral anticoagulant therapy an issue? The use of anticoagulants in renal failure carries an increased risk of complications, in particular bleeding and vascular calcifications, which could annul the advantages derived from reduced thrombotic events. Before starting oral anticoagulant therapy we suggest to carefully evaluate if there are potential overall benefits and to pay attention to concomitant antiplatelet therapy

Indicazioni all\u2019uso delle protesi vascolari per l\u2019accesso emodialitico : un\u2019esperienza italiana basata sul consenso

In Italy, the use of arteriovenous grafts (AVGs) is limited (1-4%) due to different approaches to vascular access management compared to other countries, where guidelines that may not apply to the Italian setting have been produced. Therefore, the Vascular Access Study Group of the Italian Society of Nephrology produced this position paper, providing a list of 8 recommendations built upon current guidelines. The most controversial and innovative issues of the existing guidelines have been summed up in 12 different topics. We selected 60 Italian dialysis graft experts, nephrologists and vascular surgeons (PP1SIN Study Investigators). They were asked to express their approval or disapproval on each issue, thus creating a new method to share and exchange information. Almost all agreed on specific criteria for the choice of AVG over native arteriovenous fistulas (AVF) and tunneled venous catheters (tVC) and on the necessary conditions to implant them. They did not fully agree on the use of AVG in obese patients and patients at risk of developing ischemia, as an alternative to brachiobasilic fistula with vein transposition, and in case of a poorly organized setting. When AVF is feasible, it should be preferred. AVGs are indicated when superficial veins are unavailable or to repair an AVF (bridge graft). An AVG is an alternative to tVC if the expected patient survival is long enough to allow clinical benefits. The ultimate choice of the graft type is made by the physician in charge of the surgical intervention. Antithrombotic prophylaxis may be justified in some cases

Microbial inactivation properties of a new antimicrobial/antithrombotic catheter lock solution (citrate/methylene blue/parabens)

Background. Microbial infections are the most serious complications associated with indwelling central venous catheters. A catheter lock solution that is both antibacterial and antithrombotic is needed. The goal of this study was to determine whether a new catheter lock solution containing citrate, methylene blue and parabens has antimicrobial properties against planktonic bacteria and against sessile bacteria within a biofilm. These effects were compared to the antimicrobial properties of heparin at 2500 units/ml

Ankyrin is the major oxidised protein in erythrocyte membranes from end-stage renal disease patients on chronic haemodialysis and oxidation is decreased by dialysis and vitamin C supplementation

Chronically haemodialysed end-stage renal disease patients are at high risk of morbidity arising from complications of dialysis, the underlying pathology that has led to renal disease and the complex pathology of chronic kidney disease. Anaemia is commonplace and its origins are multifactorial, involving reduced renal erythropoietin production, accumulation of uremic toxins and an increase in erythrocyte fragility. Oxidative damage is a common risk factor in renal disease and its co-morbidities and is known to cause erythrocyte fragility. Therefore, we have investigated the hypothesis that specific erythrocyte membrane proteins are more oxidised in end-stage renal disease patients and that vitamin C supplementation can ameliorate membrane protein oxidation. Eleven patients and 15 control subjects were recruited to the study. Patients were supplemented with 2 × 500 mg vitamin C per day for 4 weeks. Erythrocyte membrane proteins were prepared pre- and post-vitamin C supplementation for determination of protein oxidation. Total protein carbonyls were reduced by vitamin C supplementation but not by dialysis when investigated by enzyme linked immunosorbent assay. Using a western blot to detect oxidised proteins, one protein band, later identified as containing ankyrin, was found to be oxidised in patients but not controls and was reduced significantly by 60% in all patients after dialysis and by 20% after vitamin C treatment pre-dialysis. Ankyrin oxidation analysis may be useful in a stratified medicines approach as a possible marker to identify requirements for intervention in dialysis patients