Indications for vascular grafts as hemodialysis access: consensus from experience in Italy.

INTRODUCTION: In Italy, the use of arteriovenous grafts (AVG) is limited (1-5 %) due to different approaches to vascular access (VA) management as compared to other countries, where guidelines (which may not apply to the Italian setting) have been produced. Therefore, the Study Group (GdS) on VA of the Italian Society of Nephrology produced this position paper, providing a list of 8 recommendations built upon current guidelines. METHODS: The most controversial and innovative issues of existing guidelines have been summed up in 12 different statements. We selected 60 Italian dialysis graft experts, nephrologists and vascular surgeons (PP1SIN Study Investigators). They were asked to express their agreement/disagreement on each issue, thus creating a new method to share and exchange information. RESULTS: Most of them agreed (consensus > 90%) on specific criteria set to choose AVG over native AVF (nAVF) and tunnelled venous catheter (tVC) and on the necessary conditions to implant them. They did not fully agree on the use of AVG in obese patients, in patients at risk of developing ischemia, on the priority of AVG as an alternative to brachial-basilic fistula with vein transposition, and in case of a poorly organized setting regarding graft maintenance. Keeping in mind that the nAVF should be preferred whenever is feasible, AVGs are indicated when superficial veins are unavailable or to repair a nAVF (bridge graft). An AVG is an alternative to tVC if the expected patient survival is long enough to guarantee its clinical benefits.

Developing recommendations for vascular access for hemodialysis: Vascular Access Working Group of the Italian Society of Nephrology.

This paper presents an overview of the project carried out by the Vascular Access (VA) Working Group of the Italian Society of Nephrology with the aim of developing 4 position papers at the national level on how to choose, use, and implant the different, possible types of vascular access. The topics of the project are: 1) recommendations on the use of prosthetic arteriovenous fistulas for vascular access in hemodialysis, 2) recommendations on the use of venous catheters for hemodialysis, 3) infections induced by a venous catheter for hemodialysis, and 4) how to create and maintain a vascular access for hemodialysis. This paper also gives an explanation of the difficulties existing in Italy in the implementation of international guidelines, mostly due to significant differences in the procedures for the creation of VA, compared with the countries where most of the literature on the subject has been published. Individual position papers were drafted for each of the different topics. A list of recommendations was produced based on existing guidelines. Then these recommendations were critically reviewed by experts working in Italy, who expressed their opinion on their inclusion in position papers. The working method used to gather the opinions of the various experts is described. The final target is to provide clinicians interested in VA with updated documents on selected topics. Such documents will be updated periodically, and they will present a thorough overview of expert opinions.

[Indications for vascular grafts as dialysis access; consensus from the Italian experience]. / Indicazioni all'uso delle protesi vascolari per l'accesso emodialitico: un'esperienza 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.

[Vascular access for hemodialysis: recommendations of the Vascular Access Study Group of the Italian Society of Nephrology]. / Gli accessi vascolari per emodialisi: le raccomandazioni del Gruppo di Studio della Società Italiana di Nefrologia.

The Vascular Access Study Group of the Italian Society of Nephrology has scheduled four national studies regarding the choice, implantation and use of vascular access. Study topics will include 1) utilization of vascular grafts for hemodialysis; 2) indications and use of venous catheters; 3) tunneled central venous catheter infection; 4) organization of the implantation and repair of vascular access. After examining the difficulties in implementing international guidelines on vascular access in Italy and the differences in practice patterns between our and other countries (where the most important studies were published), the Study Group set out to prepare four position papers based on discussion of controversial aspects of the international guidelines by nephrologists and surgeons experienced in the Italian practice. An innovative operative method for verifying the consensus on vascular access practice patterns was used. The final aim was to write a document addressed to vascular access operators (surgeons and nephrologists) based on the consensus of experts on controversial vascular-access- related issues. The project will include yearly updates of the documents.

Awareness of hypertension and proteinuria in randomly selected patients in 11 Italian cities. A 2005 report of the National Kidney Foundation of Italy.

Arterial hypertension and proteinuria are risk factors for chronic kidney disease. A mobile clinic was parked in a central plaza of 11 Italian cities to check blood pressure (BP), prescribe antihypertensive drugs, assess for proteinuria, and provide awareness about hypertension. Among 3757 patients, 56% were hypertensive, 37% were not diabetic nor proteinuric with BP >or=140/90 mm Hg, 17% were diabetic or proteinuric with BP >or=130/80 mm Hg, and 11% were on treatment with BP at target. Among 1204 treated patients, 400 (33%) had controlled BP. Among all 2114 hypertensive patients, only 1344 (64%) were aware of their hypertension. Awareness was greater among treated patients at target (99%). As many as 523 (14%) patients had proteinuria >or=30 mg/dL. The authors conclude that awareness of people walking in the street about their BP and proteinuria is insufficient. Mobile screening clinics may increase public awareness and detection of hypertension and proteinuria in the general community and detect patients at risk for chronic kidney disease.

Prevention of dialysis hypotension episodes using fuzzy logic control system.

BACKGROUND: Automatic systems for stabilizing blood pressure (BP) during dialysis are few and only control those variables indirectly related to BP. Due to complex BP regulation under dynamic dialysis conditions, BP itself appears to be the most consistent input parameter for a device addressed to preventing dialysis hypotension (DH). METHODS: An automatic system (ABPS, automatic blood pressure stabilization) for BP control by fluid removal feedback regulation is implemented on a dialysis machine (Dialog Advanced, Braun). A fuzzy logic (FL) control runs in the system, using instantaneous BP as the input variable governing the ultrafiltration rate (UFR) according to the BP trend. The system is user-friendly and just requires the input of two data: critical BP (individually defined as the possible level of DH risk) and the highest UFR applicable (percentage of the mean UFR). We evaluated this system's capacity to prevent DH in 55 RDT hypotension-prone patients. Sessions with (treatment A) and without (treatment B) ABPS were alternated one-by-one for 30 dialysis sessions per patient (674 with ABPS vs 698 without). RESULTS: Despite comparable treatment times and UF volumes, severe DH appeared in 8.3% of sessions in treatment A vs 13.8% in treatment B (-39%, P=0.01). Mild DH fell non-significantly (-12.3%). There was a similar percentage of sessions in which the planned body weight loss was not achieved and dialysis time was prolonged. CONCLUSIONS: In conclusion, FL may be suited to interpreting and controlling the trend of a determined multi-variable parameter like BP. The medical knowledge of the patient and the consequent updating of input parameters depending on the patient's clinical conditions seem to be the main factors for obtaining optimal results.

Effects of growth hormone on leptin metabolism and energy expenditure in hemodialysis patients with protein-calorie malnutrition.

The relationships among growth hormone (GH), leptin, and resting energy expenditure (REE) are not understood. It has been reported that in malnourished hemodialysis patients, GH increases muscle protein synthesis, a process that requires energy. The present study evaluated the arterial levels and the forearm exchange of leptin, as well as the REE of the same patients during their participation in the same study, in four sequential 6-wk periods: I, baseline; II, GH treatment; III, washout; and IV, GH + intradialytic parenteral nutrition. During periods II and IV, patients received GH (5 mg three times per week). REE rose by 5% in period II, declined during period III, and rose by 7% during period IV. Basal leptin levels were low (2.0 +/- 0.19 ng/L). Insulin and leptin levels, as well as leptin release from the forearm, were unchanged during periods I through III but rose (+ 36%; P: < 0.05) during period IV. Changes in arterial leptin were directly related to changes in forearm leptin release (P: < 0.002), indicating a role of leptin production by peripheral tissues on leptinemia. Changes in leptin release were directly related to insulin (P: < 0.001) and, less consistently, to insulin-like growth factor-binding protein-1 levels (P: < 0.02). Similarly, variations in leptin levels were directly related to insulin (P: < 0.01). Variations in REE were not related to variations in leptin or insulin levels but to changes in muscle protein synthesis (P: < 0.025). The data show that in malnourished hemodialysis patients, treatment with GH is not invariably associated with an increase in leptin production. An increase in leptin release by peripheral tissues and leptin levels occurs only in the setting of hyperinsulinemia. The increase in REE that is induced by treatment with GH is not dependent on changes in leptin but is largely accounted for by the energy cost of the stimulation of muscle protein synthesis.