[Executive Dysfunction in Patients Undergoing Chronic Haemodialysis Treatment: A Possible Symptom of Vascular Dementia].

Introduction. Patients undergoing chronic haemodialysis (HD) treatment have an 8-10 times higher risk of experiencing stroke events and developing cognitive impairment. The high vascular stress they are subjected to may be the basis for the development of vascular dementia (VaD). Objective. The aim of the study is to investigate the executive functions, typically impaired in VaD, of patients undergoing chronic haemodialysis treatment. Method. HD patients were recruited from the U.O.C. of Nephrology and Dialysis (ASP Ragusa). Risk factors for VaD were collected and then the Frontal Assessment Battery (FAB) was administered. Results. 103 HD patients were included (males = 63%, age 66 ± 14 years). Risk factors for VaD included a high percentage of patients with anaemia (93%), hypertension (64%) and coronary artery disease (68%). The cognitive data obtained via FAB show a percentage of 55% deficit scores. All risk factors found a significant association with cognitive scores. Anemia, hypertension, intradialytic hypotension, coronary artery disease, and homocysteine are negative predictors of executive function integrity. Conclusions. More than half of the patients had deficit scores on the FAB. Reduced cognitive flexibility, high sensitivity to interference, poor inhibitory control and impaired motor programming with the dominant hand were evident. In conclusion, a marked impairment of the executive functions, generally located in the frontal lobes of the brain, was detected in the HD patient, which could be a symptom of a dementia of a vascular nature.

Vascular access for hemodialysis in Italy: What a national survey reveals.

BACKGROUND: Since in Italy there are no official data on vascular access (VA) for hemodialysis the Vascular Access Project Group (VAPG) of the Italian Society of Nephrology (SIN) designed a national survey. METHODS: A 35-question survey was designed and sent it to the Italian facilities through the SIN website. The basic questions were the prevalence, the location, and the surveillance of VA, the bedside use of ultrasound, the use of fluoroscopy for central venous catheter (CVC) placement, and of buttonhole technique, the role of nephrologist in the access creation. RESULT: The questionnaire was completed in June 2022 by 161 facilities. The survey registered 15,499 patients, approximately one-third of the Italian dialysis population. The prevalence of arteriovenous fistula (AVF), arteriovenous Graft (AVG), and CVC were 61.8%, 3.7%, and 34.5% respectively. The AVF location was 50% in distal forearm, 20% in meanproximal forearm, 30% in upper arm. For AVF creation, nephrologists were involved in 72% of facilities while for CVC placement in 62%. As regards VA monitoring, 21% of the facilities did not have a surveillance protocol; 60% did not register AVF thrombosis and 53% did not register CVC infections. Most of facilities use the fluoroscope during CVC placement, 37% when needed, and 22% never. Ultrasound-guided puncture of complex AVFs was used by 80% of facilities. Buttonhole puncture was used in 5% of patients. CONCLUSIONS: Some considerations emerge from the survey data: (1) The increasing CVC prevalence compared to DOPPS 5 study. (2) The low rate of AVG prevalence. (3) The nephrologist is the operator in many VA procedures. (4) The fluoroscopy for CVC placement and the US-guide puncture of the complex AVF are widely used in most facilities. (5) The practice of the buttonhole is not widespread. (6) When the operator is the nephrologist more distal fistulas are performed.

[Sleep quality of patients in End Stage Renal Disease before and after starting chronic hemodialysis treatment: a longitudinal study].

Introduction: Sleep disorders are very common in patients with chronic kidney disease, with a prevalence of poor sleep quality of around 40%. Objectives: The purpose of the study is to compare the sleep quality of ESRD patients before hemodialysis (Pre-HD), three months (Post-HD 1) and six months after the start of treatment (Post-HD 2) through the use of the Pittsburgh Sleep Quality Index (PSQI). Methods: Patients in ESRD were recruited from the U.O.C. of Nephrology and Dialysis of the Maggiore Hospital in Modica and biographical and anamnestic data were collected. The PSQI was administered in-person at the Pre-HD stage and by telephone re-test at the three- and six-month follow-up. Results: A total of 71 patients (males=62%, age 68 ± 16) were included. At Pre-HD assessment 93% reported poor sleep quality, the percentage increased to 98% during Post-HD 1 and it partially improved during Post-HD 2 with a prevalence of 95%. Analysis of variance (ANOVA) by repeated measures showed a difference in sleep quality between the three time points. Conclusions: Sleep quality undergoes important changes during the transition from conservative to hemodialysis patient, highlighting a critical period related to the first three months of treatment. More attention to this phase may improve the patient's quality of life and reduce the associated risk of mortality.

[Contrast Media Toxicity and Its Prevention].

Intravenous iodinated contrast media are commonly used in clinical practice, ranging from medical imaging to interventional radiology (IR) procedures and endovascular interventions. Compared with patients with normal renal function, nephropathic patients have an increased risk of acute kidney injury (AKI). Nevertheless, this condition cannot represent a limit to diagnostics or endovascular interventions. Despite the literature of the last five years, conflicting management and approaches for nephropathic patients persist, including the use of contrast agents and treatments replacing renal functions, which are often mistakenly considered as part of preventive strategies. Though the issue has been widely discussed, specialists often cope with uncertainty in handling properly the administration of contrast media and renal counselling requests. Furthermore, there is a general difficulty in distinguishing the Post-Contrast Acute Kidney Injury (PC-AKI) from the Contrast-Associated Acute Kidney Injury (CI-AKI). The present review aims to provide an update on the issue and examine strategies to reduce the acute kidney injury risk after the administration of contrast media. These strategies include the early identification of high-risk individuals, the choice of the contrast media and the proper dosage, the suspension of nephrotoxic drugs, the follow-up of the high-risk individuals, and the early identification of AKI.

Report on an Italian survey of 72 stuck hemodialysis catheters.

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Complex central venous catheter for dialysis: interventional radiology experience in insertion and management of their complications.

BACKGROUND: CVCs are defined 'complex' when they are inserted through non-conventional accesses or positioned in non-usual sites or substituted by IR endovascular procedures. We report our experience in using diagnostic and interventional radiology techniques for complex CVC insertion and management; we recommend some precautions and techniques that could lead to long-term availability of central venous access and to avoid non-conventional sites CVC insertion. METHODS: We retrospectively evaluated 617 patients, between January 2010 and December 2019, (mean age 71 ± 13; male 448/617), treated in our department for insertion of tunnelled CVC for haemodialysis. RESULTS: Among 617 patients, 241 cases (39%) are considered 'complex' because they required either a PTA with or without stenting to restore/maintain venous access or had an unusual positioning site or required unconventional access. A direct correlation between CT angiography and PTA (r = 0.95; p-value <0.001) and an inverse correlation between CT angiography and unconventional 'rescue' access (r = -0.92; p-value <0.001) were found. CONCLUSIONS: Precise pre-operative planning of treatment in a multidisciplinary setting and diagnostic and interventional radiology procedures knowledge allows reducing complex catheterisms in haemodialysis patient.

[Atheroembolic renal disease: risk factors, diagnostics, histology, and therapeutic approaches].

The increase in patients' average age, the enhancement of anticoagulation therapy and the growth of vascular interventions represent the perfect conditions for the onset of atheroembolic renal disease. AERD is observed in patients with diffuse atherosclerosis, generally after a triggering event such as surgery on the aorta, invasive procedures (angiography, catheterization of the left ventricle, coronary angioplasty) and anticoagulant or fibrinolytic therapy. The clinical signs are heterogeneous, a consequence of the occlusion of downstream small arterial vessels by cholesterol emboli coming from atheromatous plaques of the aorta, or one of its main branches. The proximity of the kidneys to the abdominal aorta, and the high flow of blood they receive, make them a major target organ. For this reason, AERD represents a pathological condition that always needs to be taken into account in the nephropathic patient, although its systemic nature makes the diagnosis difficult. This manuscript presents a review of the existing literature on this pathology, to provide an updated summary of the state of the art: risk factors, diagnostics, histology and therapeutic approaches.

[The management of nephropathic patients during the Covid-19 pandemic: the experience of Ragusa].

The public emergency caused by Covid-19 has forced health services to reorganize in order to separate positive patients from negative ones. In nephrology, this reorganization involves several levels of assistance concerning hospitalizations, ambulatory care and haemodialysis. Within the Complex Unit of Nephrology in Ragusa, the distribution of nephro-dialytic resources has involved four different hospitals, hence ensuring haemodialysis services for asymptomatic and pauci-symptomatic Covid-19 patients as well as for patients in Covid-Unit, Sub-Intensive Therapy and Intensive Care Unit. In this complex context, we had to create a common protocol involving all the professionals who provide assistance in our Unit, across the different structures. We also report some encouraging data that seem to indicate the effectiveness of the protocols put in place.

Feasibility of routine ultrasound-guided percutaneous transluminal angioplasty in the treatment of native arteriovenous fistula dysfunction.

BACKGROUND: Stenosis is the main cause of arteriovenous fistula failure and is due to neointimal hyperplasia. Percutaneous transluminal angioplasty is the gold standard for patients with vascular access stenosis. The aim of the study was to evaluate the efficacy and safety of ultrasound-guided percutaneous transluminal angioplasty in the treatment of native arteriovenous fistula venous stenosis. METHODS: The need for intervention was determined by physical examination and duplex ultrasound in 162 patients. All patients with failing or not maturing arteriovenous fistula were treated in the outpatient setting under ultrasound guidance. Procedural success was assessed with repeated post-procedural ultrasound examinations. All procedures were performed under local anesthesia by a single nephrologist and were performed in a single vascular laboratory, while follow-up ultrasound was performed in the dialysis unit of destination. RESULTS: Early technical success was obtained in 95.6% of cases (154 of 162). Complications occurred in 22 patients (13.5%) with no major complication requiring surgical or fluoroscopic endovascular intervention. Primary patency at 6 and 12 months was 84% and 69.8%, respectively. Risk factors for arteriovenous fistula failure/secondary percutaneous transluminal angioplasty were vascular access low blood flow rate and vintage, as well as the need for thrombolysis during the first percutaneous transluminal angioplasty. CONCLUSION: Ultrasound-guided percutaneous transluminal angioplasty is a valuable tool to treat vascular access stenosis.

[Therapeutic options to reduce arterial stiffness in chronic kidney disease].

Chronic kidney disease is associated with an increased cardiovascular risk. Several uremic toxins are also vascular toxins and may contribute to the increase of the cardiovascular risk through the development of aortic stiffening. In this process, oxidative stress and endothelial dysfunction play an important role. Considering that aortic stiffness is a known cardiovascular risk factor and a vascular biomarker involved in the development of chronic cardiac dysfunction, and that the reduction of aortic stiffness is associated with an improved survival of patients with end-stage kidney disease, we aim at reviewing the therapeutic options to reduce aortic stiffness and potentially the cardiovascular risk.

Treatment of juxta-anastomotic stenoses for failing distal radiocephalic arteriovenous fistulas: Drug-coated balloons versus angioplasty.

The aim of our study is to report the results of two types (type A, type B) paclitaxel drug-coated balloon compared with standard percutaneous transluminal angioplasty in the treatment of juxta-anastomotic stenoses of mature but failing distal radiocephalic hemodialysis arteriovenous fistulas. Two groups of 26 and 44 patients treated with two different drug-coated balloon are compared with a control group of 86 treated with standard percutaneous transluminal angioplasty. A color Doppler ultrasound was performed to evaluate stenosis and for treatment planning. We assess primary patency, defined as the absence of dysfunction of the arteriovenous fistulas, patent lesion or residual stenosis < 30% and no need for further reintervention of target lesion. Primary patency and secondary patency are evaluated after 12 months with color Doppler ultrasound for the whole arteriovenous fistulas, defined as absolute (absolute primary patency, absolute secondary patency) and target lesion. Postprocedural technical and clinical success was 100%. After 12 months, absolute primary patency is 81.8% for type A, 84.1% type B, and 54.7% for standard percutaneous transluminal angioplasty; target lesion primary patency is 92% type A, 86.4% type B, and 62.8% standard percutaneous transluminal angioplasty; absolute secondary patency is 95.4% type A, 95.5% type B, and 80.7% standard percutaneous transluminal angioplasty; target lesion secondary patency is 100% type A, 97.7% type B, and 80.7% standard percutaneous transluminal angioplasty. All the patients treated with drug-coated balloon (type A + type B) have an absolute primary patency of 83.3%, a target lesion primary patency of 87.9%, an absolute secondary patency of 95.5%, and a target lesion secondary patency of 98.4%. Our study confirms that the use of drug-coated balloon, indiscriminately among different brands, improves primary patency with statistically significant difference in comparison with standard percutaneous transluminal angioplasty and decreases reintervention of target lesion in juxta-anastomotic stenoses of failing distal arteriovenous fistulas maintaining the radiocephalic fistula as long as possible.

Clinical use of computational modeling for surgical planning of arteriovenous fistula for hemodialysis.

BACKGROUND: Autogenous arteriovenous fistula (AVF) is the best vascular access (VA) for hemodialysis, but its creation is still a critical procedure. Physical examination, vascular mapping and doppler ultrasound (DUS) evaluation are recommended for AVF planning, but they can not provide direct indication on AVF outcome. We recently developed and validated in a clinical trial a patient-specific computational model to predict pre-operatively the blood flow volume (BFV) in AVF for different surgical configuration on the basis of demographic, clinical and DUS data. In the present investigation we tested power of prediction and usability of the computational model in routine clinical setting. METHODS: We developed a web-based system (AVF.SIM) that integrates the computational model in a single procedure, including data collection and transfer, simulation management and data storage. A usability test on observational data was designed to compare predicted vs. measured BFV and evaluate the acceptance of the system in the clinical setting. Six Italian nephrology units were involved in the evaluation for a 6-month period that included all incident dialysis patients with indication for AVF surgery. RESULTS: Out of the 74 patients, complete data from 60 patients were included in the final dataset. Predicted brachial BFV at 40 days after surgery showed a good correlation with measured values (in average 787 ± 306 vs. 751 ± 267 mL/min, R = 0.81, p < 0.001). For distal AVFs the mean difference (±SD) between predicted vs. measured BFV was -2.0 ± 20.9%, with 50% of predicted values in the range of 86-121% of measured BFV. Feedbacks provided by clinicians indicate that AVF.SIM is easy to use and well accepted in clinical routine, with limited additional workload. CONCLUSIONS: Clinical use of computational modeling for AVF surgical planning can help the surgeon to select the best surgical strategy, reducing AVF early failures and complications. This approach allows individualization of VA care, with the aim to reduce the costs associated with VA dysfunction, and to improve AVF clinical outcome.

The vascular access in the elderly: a position statement of the Vascular Access Working Group of the Italian Society of Nephrology.

The incident hemodialysis (HD) population is aging, and the elderly group is the one with the most rapid increase. In this context it is important to define the factors associated with outcomes in elderly patients. The high prevalence of comorbidities, particularly diabetes mellitus, peripheral vascular disease and congestive heart failure, usually make vascular access (VA) creation more difficult. Furthermore, many of these patients may have an insufficient vasculature for fistula maturation. Finally, many fistulas may never be used due to the competing risk of death before dialysis initiation. In these cases, an arteriovenous graft and in some cases a central venous catheter become a valid alternative form of VA. Nephrologists need to know what is the most appropriate VA option in these patients. Age should not be a limiting factor when determining candidacy for arteriovenous fistula creation. The aim of this position statement, prepared by experts of the Vascular Access Working Group of the Italian Society of Nephrology, is to critically review the current evidence on VA in elderly HD patients. To this end, relevant clinical studies and recent guidelines on VA are reviewed and commented. The main advantages and potential drawbacks of the different VA modalities in the elderly patients are discussed.

Drug-eluting balloon for the treatment of failing hemodialytic radiocephalic arteriovenous fistulas: our experience in the treatment of juxta-anastomotic stenoses.

PURPOSE: The purpose of this article is to report our experience with drug-eluting balloons for the treatment of juxta-anastomotic stenoses of failing radiocephalic hemodialytic arteriovenous shunt and to evaluate the primary and secondary patency (PP and SP). METHODS: After approval by the local hospital's Ethical and Scientific Review Board, 26 consecutive patients with juxta-anastomotic stenosis of radiocephalic hemodialytic shunt were treated with angioplasty with drug-eluting balloon. The main objective was to evaluate PP defined, in accordance with the Kidney Disease Outcomes Quality Initiative recommendation, as the absence of dysfunction of the vascular access, patent lesion or residual stenosis <30% and no need for further reintervention of the target lesion (TL). PP and SP at 6, 12 and 24 months were evaluated, with echo color doppler and phlebography, for both arteriovenous fistulae, defined as absolute, and TL. RESULTS: Immediate postprocedural technical and clinical success was 100% for all the patients; we had only one technical failure in repeated treatments. At 6 months the absolute and TL PP was 96.1%; at 12 months the absolute PP was 81.8%, TL PP 90.9%, absolute SP 95.4%, TL SP 100%; at 24 months the absolute and TL PP was 57.8%; absolute and TL SP 94.7%; only one arteriovenous fistula was lost during the period. CONCLUSIONS: The use of drug-eluting balloons, after standard angioplasty, improves primary patency and decreases reinterventions of TL in juxta-anastomotic stenoses of failing native dialytic arteriovenous shunts.

[Project work: formation of health-care personnel for self-care of tunnelled central venous catheters in hemodialysis patients of the territory]. / Project work: formazione infermieristica per l'autocura educativa dei cateteri venosi tunnellizzati nei pazienti emodializzati del territorio.

BACKGROUND: Scientific data from current literature demonstrate an incidence of bacteraemia due to tunnelled central venous catheter (tCVC) use accounting for 1.6 / 1000 days per tCVC, with a range of 1.5 to 1.8. In Sicily no data on the incidence of tCVC- related bacteraemia are available. In our hospital, tCVC infection occurs 2.4 times in 1000 days during CVC use. A retrospective analysis carried out from 2006 to 2012 was performed on 650 patients with tunnelled catheters. Of the subjects who received tCVC in our hospital, 90% were destined to undergo haemodialysis in a private health care environment outside our hospital. MATERIALS AND METHODS: In order to improve the aforementioned infection outcome, we planned and implemented a specific work project. The work project (WP) was subdivided into two steps: 1) The first step was further subdivided into two sub-phases. The first was principally concerned with the implementation of educational courses, conducted directly on the ward and aimed at the implementation of meticulous nursing regimes for the care of tCVC by our health care nurse. The courses were entitled Management of Vascular Access: from doing - to teaching to do!. These educational courses were organized by the Nephrology Department, which takes care of the management and handling of the major complications of tCVCs for the maintenance of haemodialysis. After this first step, the nurses who had participated became the promoters of the second part of the course, which concerned the development of know-how within an outpatient clinic, which deals exclusively with the nursing management of tCVCs. 2) The title of the second phase was Therapeutic Education: self-Care and understanding and managing your venous access at home. The aim of this step was the integration of correct in-hospital care with that available in outsourced private institutions, via the involvement of the patient in the management of their own central venous access. During our training project, a more detailed analysis of the stakeholder as well as a swot analysis on the feasibility of the project were used to determine ad interim and final targets of the study. A summary of operative planning is included to explain in greater detail the study design, timing and costs of the various phases. Risk management and corrective measures adopted during the project are also mentioned and monitoring of the phases is described in relation to the fulfilling of intermediate goals. The prompt correction of mistakes allows for safer realisation of outcomes. CONCLUSION: From our experience with this work project, we can conclude that a more accurate management of tCVCs can significantly reduce the morbidity and mortality of patients. The project offers a positive cost-benefit balance through a decrease in costs of hospitalisation for tCVC-related infections and other life.threatening conditions related to the use of tCVCs an important goal for any spending review.

Venae comitantes as a potential vascular resource to create native arteriovenous fistulae.

PURPOSE: The arteriovenous fistula (AVF) represents the gold standard for hemodialysis (HD) vascular access. In some critical cases, use of the deep venous circle may represent an alternative approach and venae comitantes could be employed for this purpose. METHODS: Sixty patients with chronic renal failure in which the deep venous circle was used to create an AVF were identified; of the 48 who had a direct anastomosis between the brachial artery and vena comitans, 42 had a long-term follow-up (mean follow-up 59 weeks), while six were lost to follow-up. RESULTS: Immediate success (patency and palpable thrill) was achieved in 88% of cases (primary and early failure 12%). Primary accessibility rate was 62%, while 11 patients required a second surgical approach to make the vein accessible to needling. Secondary accessibility rate of 71% was due to surgical revisions. In the 80-week observation period, the complication rate was 10% with irreversible loss of the AVF in all these cases. Cumulative patency was 71% at the 80th week. Including all 42 patients, technical and functional success rate, defined as vein accessibility to needling and chance of an adequate HD treatment, was 62%. CONCLUSIONS: AVF employing venae comitantes may represent a suitable alternative in the absence of other vascular accesses for HD.

Atypical placement of hemodialysis catheters in patients with complete and irreversible obstruction of central venous vessels.

PURPOSE: This article describes the approach to atypical placement of central venous catheters (CVC) in dialysis patients with complete untreatable obstruction of central venous vessels. METHODS: Five patients with complete obstruction of central venous vessels underwent CT venography and digital venous angiography. After ultrasound-guided and radioscopic-assisted cannulation of the internal jugular vein, permanent CVCs were placed in atypical locations: in two patients a preliminary venous angioplasty was performed to facilitate the catheter positioning in a mediastinal enlarged collateral vein and in a persistent left superior vena cava; in three patients the CVC was placed in the azygos vein, enlarged because of the obstruction of the superior vena cava. RESULTS: In all cases, we achieved satisfactory morphological and functional immediate results. Hemodialysis (HD) was carried out long term in all patients except one who presented a non-functioning CVC after 4 months. In one case the catheter, still functioning well after 9 months, was removed due to kidney transplantation. The CVC in the left superior vena cava was replaced with a longer one after 12 months, and it is still functioning well 3 months after replacement. The patency of the other two catheters has to date been kept for 9 and 18 months. CONCLUSIONS: The placement of CVC for HD in atypical sites can be considered a viable option in extreme cases; adequate imaging support is paramount in order to facilitate the procedure and to avoid complications.

[Multislice computed tomographic angiography in the assessment of central veins for endovascular treatment planning: comparison with phlebography]. / Angio-TC MS nello studio dei vasi venosi centrali per la pianificazione del trattamento endovascolare: studio comparativo con la flebografia.

The dysfunction of a vascular access for hemodialysis and its loss may depend on drainage difficulties of the superficial or deep venation due to hemodynamically significant stenosis or obstruction of a central vein, which generally involve the innominate-subclavian veins or superior vena cava. These alterations are often neglected due to their central and deep location; when there is hemodynamic compensation, they may remain asymptomatic. For these reasons every suspect clinical sign for central vein stenosis (gross arm syndrome or venous hypertension in an arteriovenous fistula) must not be ignored, as timely intervention is essential for functional recovery of the vessel and for the protection of the arteriovenous fistula. The modern imaging techniques ensure thorough diagnostic assessment, while the possibilities of endovascular treatment with interventional radiology allow, in a large proportion of cases, optimal minimally invasive treatment, but above all the recovery of venation in a hemodialyzed patient. We report our experience with multislice computed tomographic angiography (MS-CTA) and reconstruction software for treatment planning of central vein stenosis or obstruction. Forty-nine patients were studied with MS-CTA (GE 16). Images were acquired in the venous phase (120-180 seconds after contrast medium injection) followed by digital vascular reconstruction (AutoBone for bone removal, vessel analysis for caliber and length measurements, thin and curved MIP, MPR). Within a week control phlebography was performed. The venous tree was divided into seven segments and analyzed in a double-blind fashion with a distinction between patent segments, 50-70% stenosis, >70% stenosis, occlusion, and collateral vascular beds. There was excellent correspondence in all the examined segments for patency, >70% stenosis, and occlusion, with high sensitivity (98%), specificity (99.3%), and diagnostic accuracy (99.1%). The binomial test demonstrated a highly significant concordance (alpha=0.99) for all patients and in all vascular segments with the exception of 70% stenoses, in which MS-CTA gave a slight overestimate. In the central venous district, color Doppler ultrasonography may not be as effective as for the peripheral study of arteriovenous fistulae, and second-level imaging techniques such as MS-CTA are more useful. We suggest that endovascular treatment must be preceded by MS-CTA. This examination shows the lesions that may benefit from endovascular treatment and recognizes ''uncrossable'' lesions, ie, the ones that will not benefit from treatment. Moreover, it allows accurate planning of endovascular treatment by showing the lesion type (stenosis or obstruction), the position and extension of the involved vessels, the vessel caliber above and below the lesion, and the possible presence of a collateral vascular bed. MS-CTA with dedicated reconstruction software, if correctly performed and accurately reconstructed, is a precious tool for diagnosis and treatment planning.