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���������������� ������������ �������������� 23 ���������������������� ������������������������ ���� ������������������������ ����-�������������� �� �������������� �� ������������������������ �������������� ���������������������� ���������������� ������������������������������ �� ���������������������������� �������������������������� ���������������� (Venoflow) (n = 10), �������������������� �������������������������������� �������������������������������� (�������������� ���������������� ���������������� ����������, ���������������������������������� 5 % ������������������ ��������������������, n = 9) �� �������������������������������� v. saphena magna (n = 4), ���������������������� ���� ������������ 2018-2021 ����. ������������������ ����-�������������� ���� ������������ ������������������������������ �� �������������� �� ������������������������ �������������� ���������������������� ���������������� ������������������������������ �������� �������������������������� �� ���������� ������������ ���������������� ������������ �� �������������� ���������������������������������� �������������������� �� ���������� �������������� �������������������������� ���������������������� ��������������., The analysis of the outcomes of 23 surgical interventions for the formation of AV grafts in patients with end-stage chronic renal failure using synthetic prostheses (Venoflow) (n = 10), vascular xenobioprostheses "KemAngioprosthesis" (cattle artery structured with 5 % diepoxide solution, n = 9) and translocated v. saphena magna (n = 4), performed for the period 2018-2021. Installation of AV grafts based on a xenobioprosthesis in patients with end-stage chronic renal failure was associated with a lower incidence of early and late postoperative complications and a higher survival of the vascular access.

Recent advances in technology show promise in providing greater vascular access options for hemodialysis patients. This review discusses novel methods for creating an anastomosis for arteriovenous (AV) fistulas and new materials for prosthetic AV grafts. Two technologies for endovascular arteriovenous fistula creation, the Ellipsys and WavelinQ endovascular systems, are discussed. When an AV fistula is not possible, an AV graft or devices to augment the AV fistula may be appropriate. New materials that have been developed that show promise as an alternative to the expanded polytetrafluoroethylene graft are discussed. Such potential conduits include bioengineered vessels and both allogenic or xenogenic biologic grafts. Devices designed to optimize blood flow to reduce maturation failure and improve AV fistula outcomes are explored.

Rationale & objective Creation of an arteriovenous fistula (AVF), compared to an AV graft (AVG), is associated with longer initial catheter dependence after starting hemodialysis but longer access survival and lower long-term catheter dependence. The extent of these potential long-term benefits in elderly patients is unknown. We assessed catheter dependence after AVF or AVG placement among elderly patients who initiated HD without a permanent access in place. Study design Retrospective cohort study. Setting& participants Patients ≥67 years of age identified in the United States Renal Data System (USRDS) who had a first AVF (n=14,532) or AVG (n=3391) placed within 1 year after HD initiation between May 2012 and May 2017. Exposure AVF versus AVG placement in first year of hemodialysis. Outcome Catheter dependence after AVF or AVG placement assessed using CROWNWeb data. ANALYTICAL APPROACH: - Generalized estimating equations and negative binomial regression for catheter use over time and Cox proportional hazards models for mortality. Results Creation of an AVF versus AVG was associated with greater catheter dependence at one month (95.6% vs. 92.5%) and at three months (82.8% vs. 41.2%), but lower catheter dependence at 12 months (14.2% vs. 15.8%) and at 36 months (8.2% vs. 15.0%). Creation of an AVF, however, remained significantly associated with greater cumulative catheter-dependent days (80.1 vs 54.6 days per person-year) and a lower proportion of catheter-free survival time (78.1% vs 85.1%) after three years of follow-up. Limitations Potential for unmeasured confounding and analyses limited to elderly patients. Conclusions Creation of an AVF was associated with significantly greater cumulative catheter dependence than placement of an AVG in an elderly population initiating HD without a permanent access. As the long-term benefits in terms of catheter dependency of an AVF are not realized in many elderly patients, specific patient characteristics should be considered when making decisions regarding vascular access.

Purpose Hemodialysis (HD) patients who are female or black receive fewer arteriovenous fistulas (AVF) and more grafts (AVG). We evaluated race- and sex-based differences for three process exposures: access surgery, peripherally-inserted central catheters (PICCs), and vascular imaging. Methods US Renal Data System with linked Medicare claims for patients initiating HD between April 2010 – December 2011 were used to identify PICC placement, imaging, AVF and AVG surgeries, and the vascular accesses in use at individual HD treatments. Poisson, logistic, and Cox regression models adjusted for clinical and demographic variables were used to evaluate relationships between process exposures, vascular access outcomes, and sex. Results Among 18,883 individuals initiating HD with catheters with at least one surgical claim for AVF or AVG, women had 16% more PICC and 5% more imaging (p = 0.002), were 43% less likely to have AVF surgery and 68% more likely to have AVG surgery (pConclusions Divergences in vascular access by race and sex were partly related to differential process exposures. Black and female patients had more AVG and less AVF surgery, and more PICC and imaging. Success rates were lower for AVF surgery and higher for AVG surgery. Further work is needed to determine whether choices of process exposures arise from differential ability to detect veins on physical examination.

Objective: The objective of the study was to analyze and evaluate the possible factors in the long-term patency of arteriovenous (AV) access for hemodialysis (HD). Materials and Methods: This was a cross-sectional study recruiting patients from January 2019 to December 2019. All patients who have a working HD vascular access, either AV fistula (AVF) or AV graft which has been working for at least 2 years were included and collected demographic data along with other parameters such as timing of creation, interventions, dialysis sessions, and antiplatelet therapy among others. Results: We included 81 patients with AV access patent more than 2 years; 22.5% were aged >65 years, 39.6% were diabetic, 68.5% were hypertensive, and 26.1% had vascular disease. Analysis revealed that the patient factors such as current tobacco usage and side of creation and technical factors such as maturation time, number of dialysis sessions, and single-center dialysis have a significant effect on the patency of the AV access, while the factors such as past tobacco usage, diabetes, hypertension, use of jugular catheter before access creation, and cannulation technique could not establish any statistical effect on the patency of AV access. Conclusion: There is a complex interaction of factors that may affect the patency of an individual AV access. These need to be carefully considered when selecting surgical site or technique, adjuvant treatments, and follow-up protocols for AVFs.

Evaluating the safety and efficacy of the AVflo™ graft in terms of patency and complications (early and late) over 2 years.Twelve end-stage renal disease (ESRD) patients (age: mean 68.5 ± 10 years) were followed up for a mean period of 946 ± 570 days after receiving an implantation of the graft for HD. The grafts were implanted at the lower arm (loop configuration), upper arm (straight configuration) and the thigh (loop configuration). First dialysis was performed at day 7 (3-21) following implantation.After a mean follow up of 24 months, the primary patency was 56% and the secondary patency was 82%. In this group, AVflo™ shows similar if not superior efficacy and safety to that of available grafts in terms of safety, complications, and long-term patency.

Establishing venous access in chronic dialysis patients is conducted by the insertion of polytetrafluoroethylene arterial-venous (AV) grafts. The continual access of these grafts allows for potential failure over extended periods of hemodialysis treatment, as a result of thrombosis and pseudoaneurysm formation. Patency of AV grafts requires interventional management of thrombosis and pseudoaneurysm formation, including thrombectomy and covered stent placement, respectively. In 2013, the Food and Drug Administration approved the Gore REVISE study, giving indication for covered stents within AV grafts. If covered stent placement is required to treat a thrombosed AV graft, it is still possible to perform a percutaneous thrombectomy procedure afterwards. Direct access of the AV graft by passing through both the graft material and covered stents allows for interventional radiology management to be performed without compromise of the stent or graft. This interventional method of direct access can salvage the AV graft before considering further invasive management, such as a new surgical venous access site.

Patients on chronic hemodialysis (HD) required efficient arterio-venous access. Different types of vascular access are commonly used, such as native arteriovenous (AV) fistula, prosthetic AV graft, central venous catheter, or temporary and tunnelled cuffed catheters. Vascular access—related morbidity remains the major issue for patients requiring long-term therapy. Vascular access infection constitutes the most challenging and life-threatening complication of vascular access and causes significant morbidity, loss of access and mortality. Vascular access infection is defined as local signs at the vascular access site or a positive blood culture with no know source other than the vascular access. The critical issue in the management of AV graft infection is the need to remove the infection and to maintain HD access with reduced morbidity. The diagnosis of infected AV graft is not always easy, especially with low-grade infection or atypical presentation. Fluorodeoxyglucose positron emission tomography (FDG-PET) is an imaging method that uses a radioactively labelled tracer (18 fluorodeoxy glucose) which is taken up by tissue with high metabolic activity, such as neoplastic and inflammatory lesions. FDG-PET has been proposed to visualise localisation of infection in patients with suspected prosthetic graft infection. We report a case of methicilin resistant staphylococcus aureus (MRSA) hemodialysis access infection without local inflammatory signs diagnosed on the PET-CT.

This is the first reported case of an unusual complication of upper extremity swelling of the arm in a patient with an arteriovenous (AV) graft for haemodialysis. A graftogram demonstrated an aberrant fistula formation between the native arterial branch and the AV graft (aberrant arterio-graft fistula). Inadvertent back wall laceration of the AV graft during haemodialysis cannulation was postulated to be the aetiology. Aberrant arterio-graft fistula formation may be hard to diagnose because of the presence of thrill or bruit at the level of the anastomoses and rarity of the complication. Progression of extremity swelling with or without central venous occlusion should raise the suspicion and sought further investigation. Proper cannulation techniques prior to haemodialysis may prevent such complications.

Background: The use of an arteriovenous (AV) graft for hemodialysis is associated with a relatively high rate of thrombosis. Unfortunately, the urgent thrombectomy is not always readily available. Our aim was to investigate a possible association between the timing of thrombectomy and the patency rates of AV grafts. Methods: A retrospective single-center study on patients who underwent thrombectomy of clotted AV grafts was conducted. According to the time of thrombectomy, all patients were divided into 4 groups. Results: Primary graft patency at 6 months after thrombectomy was 28.3%, with no significant difference between the study groups ( P = .161). Secondary graft patency at 6 months was significantly worse in the group that underwent thrombectomy between the third and fifth days than in the whole cohort: 15.4% versus 45.6% ( P = .038). Conclusions: Timing of thrombectomy of a clotted AV graft may have a significant impact on the graft survival.

A new methodology for simulating the flow field inside an arteriovenous (AV) graft to vein anastomoses by the adaptive neuro fuzzy inference system (ANFIS) is presented in this study. For determining the optimal AV graft angle, an ANFIS-based model of neuro fuzzy-graft-vein (NF-GVEIN) is proposed. Therefore engineering design of the graft can be supported. The advantage of this neuro-fuzzy hybrid model is that it does not require the model structure to be known a priori, in contrast to most of the modeling techniques. A case study with real experimental data was carried out. NFGVEIN was optimized by means of selection of the algorithm among 34 ANFIS algorithms by terms of minimal error. The optimal neural network structure was determined. The optimal AV graft angle causing the least turbulence was obtained. The simulation results showed that this model is feasible for forecasting of finding the optimal AV graft angle inside AV graft to vein anastomoses with different flow rates.

Vascular access is the Achilles’ heel of hemodialysis. Current vascular access approaches for hemodialysis include arteriovenous (AV) fistula, AV graft, and central venous catheter. Strengths and weaknesses of each access type are described. New technology and procedures in introducing an access, monitoring access function, and salvaging a non-functioning access are also described.

Assessing treatment efficacies for preventing haemodialysis arteriovenous (AV) graft stenosis requires a reproducible method for quantifying intimal hyperplasia. We identified sources of variability in three histological methods for assessing hyperplasia in a porcine AV graft model.Carotid-jugular synthetic grafts were placed in pigs. After explantation at 3-6 weeks, the tissue was stained with haematoxylin and eosin (HE), Masson's trichrome or elastic tissue Van Gieson (EVG) stains and examined histologically. Hyperplasia at the anastomosis of 14 grafts was quantified using three different methods, each by four blinded observers. These methods were visual scoring, ratio of intima-to-media surface area (I/M ratio), and ratio of intra-graft hyperplasia to graft surface area (H/G ratio) at the graft-vessel interface.The EVG stain proved superior in delineation of the elastic lamina yet quantification of the intimal and medial layers was still often difficult. This is illustrated by the greater inter-observer median coefficient of variances (CV) found using the I/M ratio method (intimal area CV=13.7%; medial area CV=32.7%; I/M ratio CV=44.0%) than with the H/G method (intra-graft hyperplasia area CV=7.3%, graft area CV=5.3%; H/G ratio CV=6.9%) or by visual scoring (CV=26.8%). The H/G ratios correlated positively with visual scores (r=0.941; P=0.0007; n=14) and the I/M ratio (r=0.719; P=0.0095; n=14). While hyperplasia was seen in both native vessel and graft lumen, in only one of the 14 anastomoses was the degree of hyperplasia greater in the native vessel than in the graft lumen, suggesting that the degree of hyperplasia occurring within the graft lumen predicted the total hyperplasia around the anastomosis.The H/G method for assessing hyperplasia is preferred in a porcine model of AV graft because it is quantitative, less variable and does not require the delineation of the elastic lamina, although it infrequently underestimates the total hyperplasia that occurs.

In this article, the authors present approaches they use in performing dialysis access intervention-in particular clotted access. It is not meant to be a comprehensive review of dialysis access management. At our institution, mechanical thrombectomy is the primary mode of treatment for clotted hemodialysis access. We will present physical examination findings in clotted dialysis access and contraindications for mechanical thrombectomy in dialysis access. We will also discuss the devices for mechanical thrombectomy and the techniques we use. Finally, we will discuss the difficulties encountered in these procedures and their solutions.

The most preferable method of vascular access (VA) in maintenance hemodialysis is a native arteriovenous fistula (AVF). Advanced age as well as the rapid increase in underlying diseases such as diabetic nephropathy and nephrosclerosis in these patients also means that the veins and arteries used to establish the AVF have undergone vascular damage, making construction of an AVF more difficult compared with earlier construction. Although there are various conditions under which arterial superficialization or AV graft must be chosen, it remains the rule that the first choice for VA should be AVF whenever possible. To improve postoperative results, it is necessary to reduce malfunctions immediately following surgery. We conducted a survey of 23 dialysis facilities throughout Japan and analyzed data from the past 3 years regarding the functionality of the AVF at initial puncture following construction of 5007 examples of newly constructed AVFs. Upon initial puncture, primary failure (PF) is defined as those cases in which thrombosis or inadequate blood flow occur. Primary failure occurred in 7.6% of the cases in this series, but there was a wide distribution of PF, 0.8% to 23.6%, because of differences in quality among facilities. This difference in PF is probably affected by technical aspects, the main factor being the characteristics of the patient. Survey responses included: (1) vascular damage of the veins and arteries used in creating the AVF and (2) the suitability of the location chosen for construction. In the data collected, many methods were used to repair those primary AFVs in which PF occurred. The salvage rate was 70%. Currently, the most preferable form of VA is AVF adhering to the principle that the proper timing of the choice and construction of AVF should consider the maturation period. To accomplish this, it is vital that vascular mapping be performed preoperatively to construct the AVF. If PF does occur, the cause should be thoroughly investigated and repairs made effectively.

When expanded polytetrafluoroethylene (PTFE) is used for hemodialysis access, the authors' initial preference is a forearm loop arteriovenous (AV) graft below the antecubital fossa. However, AV graft thrombosis remains a significant problem caused mainly by venous outflow hyperplasia and managed often by either surgical or radiologic thrombectomy and angioplasty. At the time of surgical revision, the lack of an adequate superficial or deep forearm outflow vein below the elbow would require an antecubital (across the elbow) jump bypass revision to a more proximal upper arm vein to salvage the original forearm AV graft. With an increasing interest in monitoring the specific outcomes of the different surgical interventions used to salvage thrombosed hemoaccess, the authors reviewed their most recent 24--month experience of 32 antecubital jump revisions using ring reinforced PTFE. The mean primary patency of these antecubital jump revisions was 8.2 months with 18 presently patent. AV grafts revisions using antecubital jump grafts confer additional patency; they are another important method for salvaging thrombosed AV hemodialysis grafts.

Cryopreserved allografts have demonstrated resistance to infection similar to that of autogenous tissue when used for the treatment of prosthetic arterial bypass graft infections. As the number of hemodialysis access procedures increases, prosthetic hemodialysis graft infection has become a significant problem. We have used the cryopreserved femoral vein as an alternative conduit in the treatment of prosthetic arteriovenous (AV) hemodialysis graft infections. Forty-eight cryopreserved femoral vein AV graft procedures were performed. The 1-year primary graft patency rate was 49%, while the secondary graft patency rate was 75%. No subsequent cryopreserved allograft infections occurred. The cryopreserved femoral vein graft is a safe, durable, and infection resistant conduit for the treatment of prosthetic AV hemodialysis graft infections.

The optimal treatment of arteriovenous (AV) grafts requires a multidisciplinary approach to the management of graft pathology. Open surgical and percutaneous methods must complement each other. Patient care can be enhanced if the indications, strengths, and weaknesses of a given technique are understood by all those involved in patient care. Continued study of the relative efficacy of the various techniques and clinical algorithms is indicated so that the most appropriate procedure is undertaken for a given pathology. This article reviews graft pathology treated via open surgical intervention. The interventionalist must have a thorough understanding of surgical treatment options so that an appropriate and timely referral can be made. The need for the interventionalist to evaluate a wide range of graft pathology and to decide on the most appropriate treatment is becoming more important, because in many institutions, the interventionalist has become the primary referral physician for AV graft dysfunction.

Central venous stenosis (CVS) is a relatively common problem in the hemodialysis patients and results in significant morbidity. It is often clinically apparent in those with functioning hemodialysis access, either as an autogenous arteriovenous (AV) fistula or an AV graft that is not a normal physiologic situation. The likely cause of CVS is the development of venous intimal hyperplasia from chronic trauma caused by repeated catheterization for interval access. Furthermore, the high turbulent flow from an existing AV access may potentiate development of the stenosis. The most common manifestations of central venous stenosis are ipsilateral arm or neck swelling, elevation of the venous pressure during hemodialysis, and hemodialysis access failure. CVS is frustrating to deal with, both for patients and providers alike.

An adequate strategy for selecting venous outflow for repeated vascular access plays a major role in determining the long term survival of patients in a haemodialysis programme. Since the first description of the method for creating an arteriovenous (AV) fistula by Brescia et al., numerous techniques and materials have been tried in order to achieve better patency rates. However, failure of vascular access continues to be the main cause of hospital admission in haemodialysis patients. Although surgery for vascular access is commonly performed by most vascular surgeons, the search for a suitable venous outflow is often hampered by the progressive exhausting of superficial veins, due to repeated punctures or failure of previously fashioned access conduits. An AV graft constructed in a loop fashion, between the brachial artery and the superficial forearm veins, is the usual technique in most centres. However, the use of deep forearm veins as an outflow for an AV, and their role as an alternative choice after a previously failed fistula, has scarcely been analysed. In this short report, a description of the procedure and preliminary results are discussed.

Prosthetic arteriovenous (AV) graft is the second most common vascular access of choice in hemodialysis patients. Rare complications of such grafts are increasingly seen due to rising population of patients on hemodialysis. Infections and thrombosis are the most common complications. Though metallic implants are known to cause hypersensitivity skin reactions, prosthetic AV grafts are rarely known to cause such kind of reactions due to inert nature of materials used in their preparation. We present a case of 54-year-old male who developed contact dermatitis after AV graft creation which was mistreated initially as infection.

The main purpose of this paper is to aid nephrologist and vascular access surgeons in the decision “Which Access is the Most Appropriate for your patient?” At the present time there are three types of hemodialysis access, mainly AV Fistula, AV Graft and Double Lumen Central Line Catheter. We would hope to help the physicians determine which is the most appropriate type of access in each patient? We will show that a multi-disciplinary team will go far into helping make this decision. Furthermore it is imperative that a complete work up must be done including vein mapping and arterial evaluation prior to any surgery. It is well known that long term use of double lumen catheters lead to a very high infection rate as well as stenosis of the major central vessels. Research has shown that after 10 years there is no significant statistical difference in the patency of grafts and fistula. It is the feeling of most surgeons and nephrologist that a good working AV fistula is a superior conduit for dialysis. With a good multi-disciplinary team and early referral of a patient to a surgeon, he is more likely to be able to create an AV fistula before the veins have been injured by I/V’s and blood draws. If there are no veins available for an AV fistula, an early cannulation graft is far superior to a Double lumen catheter.

No controlled studies investigating the effect of specific cannulation techniques on AV graft survival time and/or patency rates appear in the literature. These techniques include but are not limited to the following: skin preparation, rotation of cannulation sites, antegrade versus retrograde cannulation, rotating the axis of the needle, rerotating axis before removal, local injection versus topical application of anesthetics versus no anesthesia, and postdialysis site care and dressings. There have been no investigations published in the recent literature concerning the benefits of antegrade versus retrograde access cannulation. The difficulty validating the idea that antegrade cannulation may be more beneficial than retrograde, from a practical standpoint, is that few dialysis units use only one method. In addition, some clinicians change their method from one patient to the next. Does antegrade or retrograde cannulation create an incisional flap that is better approximated as the Qb passes over it after hemostasis occurs? Is there a difference in the incidence of stenosis in the arterial end of synthetic AV grafts exposed to antegrade cannulation versus those exposed to retrograde cannulation? No studies of blood recirculation at varying blood flow rates appear in the current literature. There is little mention of time required for hemostasis as an indication of patency of the AV graft. Are increases in time required to accomplish hemostasis after needle removal related to graft patency? Can one show distinct patterns in time to hemostasis at certain levels of patency?(ABSTRACT TRUNCATED AT 250 WORDS)

Purpose The surgically placed dialysis arteriovenous fistula (AVF) is considered by the Kidney Disease Outcomes Quality Initiative (KDOQI) and the Fistula First Breakthrough Initiative to be the ideal choice for hemodialysis access. A significant number of newly placed AVFs either slowly or never adequately mature sufficiently to provide for adequate dialysis. The balloon-assisted maturation (BAM) procedure utilizes serial angioplasty to promote and accelerate AVF maturation. We present a minimally invasive AVF maturation technique utilizing angioplasty, stent-graft, and coil embolization. Methods A 41–year-old white woman presented with an nonmaturing AVF with multiple venous outflow channels. An adequately functioning AVF was achieved after 2 treatments including coil embolization, angioplasty, and stent-graft placement. Results Adequate thrill and dialysis flow was achieved. Patient has done well during short-term follow-up without further intervention. Conclusions BAM techniques can be an effective tool to help a dialysis patient achieve an adequately mature AVF. Additional vascular interventional techniques may be utilized to further improve clinical results. For the purpose of this report we call this technique “augmented balloon-assisted maturation,” or aBAM.

Current clinical practice patterns have led to the performance of many percutaneous vascular procedures outside the traditional operating room and led to significant changes in management strategies for treatment of complications of arteriovenous access. In an effort to identify optimal treatment for failed or failing arteriovenous fistulas and grafts, percutaneous and surgical techniques are analyzed. Assessment of the functioning or failing access by physical examination is critical in determining proper treatment and in assessing outcomes of interventions. Percutaneous and surgical techniques are available for the treatment of AV access thrombosis and venous stenosis. Techniques for percutaneous thrombectomy and stent placement for venous stenosis and AV graft pseudoaneurysms are reviewed. Management of arterial inflow disease, steal syndrome and nonmaturing AV fistulas is also addressed. Overall, percutaneous techniques are assuming an increasingly important role in the treatment of failed or failing AV fistulas and grafts. Ongoing analysis of outcomes of both percutaneous and surgical interventions is necessary to continue to identify optimum treatment algorithms.

Common interventional procedures on frequently encountered patients may wrongly place one on a track that deals with the task at hand while not assessing the global patient. Nowhere is this more problematic than in the dialysis population where in the course of achieving and maintaining vascular access, the interventionist becomes exceedingly familiar with each patient and his or her particular clinical history. Unfortunately, events that may have occurred in the past few hours may rarely be overlooked. We present a case of patient mortality as an indirect result of an upper extremity polytetrafluoroethylene graft thrombectomy-thrombolysis procedure that followed attempted nontunneled catheter placement via the groin.

Purpose To evaluate the functional effects of preventive vascular access (VA) intervention through periodic blood flow (QA) measurements during hemodialysis (HD) by the delta-H method. Methods We prospectively monitored the blood flow rate (QA) of 100 VA (arteriovenous fistula (AVF) 81% or AV graft (AVG) 19%; mean VA duration 24.6 ± 42.3 months) during HD in 89 end-stage renal disease patients (mean age 62.7 ± 13.6 yrs; mean time on HD 30.9 ± 43.9 months; 18% with diabetes) over a 3-yr period. QA was measured at least every 4 months by the delta-H method (Yarar (6)) using the Crit Line III Monitor (overall mean QA 1247.6 ± 519.7 ml/min). The mean arterial pressure (MAP) and Kt/V index were measured simultaneously with QA. Thirty-eight VA (38%) met the positive evaluation criteria (absolute QA A decreased >20% from baseline 50%). Most cases with positive evaluation underwent angiography (36/38, 95%) and had stenosis ≥50% (34/36, 94%). Of VA with significant stenosis, 17 (17/34, 50%) VA (AVF 76.5%, AVG 23.5%; mean VA duration 12.5 ± 22.4 months, mean percentage of VA stenosis 75.8%) in 15 patients (mean age 68.4 ± 9.8 yrs; mean time on HD 14.2 ± 18.2 months; 33.3% with diabetes) underwent corrective intervention by angioplasty, 35.3% (6/17), and revision surgery, 64.7% (11/17). Results Short-term results: Elective intervention was successful in 88% of treated VA (15/17). Mean QA increased from 563.8 ± 115.4 ml/min just before intervention (QA pre) to 975.7 ± 351.8 ml/min just after intervention (QA post) (mean ΔQA = 411.8 ± 290.1 ml/min) (p < 0.001). We found a significant difference between the overall mean QA before (689.6 ± 227.0 ml/min) vs after intervention (965.9 ± 396.8 ml/min) (p = 0.011). No difference was found when the highest recorded mean QA before intervention (877.7 ± 415.4 ml/min) and mean QA post were compared (p = 0.25). Mean MAP did not change after intervention (91.5 ± 12.5 vs 92.7 ± 14.2 mmHg, p = 0.46). Mean Kt/V index improved from 1.44 ± 0.24 just before intervention to 1.49 ± 0.23 just after intervention without any change in dialyzer type or HD duration (p = 0.025). Mean ΔQA was similar for diabetic patients vs non-diabetic patients (p = 0.34), for younger patients (age < 65 yrs) vs older patients (age ≥65 yrs) (p = 0.64) and for AVF vs AVG (p = 0.39). We found a positive correlation between mean ΔQA and mean QA post (r = 0.95, p < 0.001) or between mean ΔQA and overall mean QA after intervention (r = 0.77, p < 0.001). Long-term results Prevalence of VA thrombosis during the follow-up period (354.4 ± 293.1 days): 17.6% (3/17). Five (29.4%) treated VA showed restenosis and two of them (40%) underwent reintervention by surgery. Mean restenosis period and mean decrease in QA were 232.6 ± 74.1 days and 2.8 ± 0.6 ml/min/day, respectively. No significant correlation was found between mean ΔQA or QA pre and mean restenosis period or decrease in QA (p = ns). Conclusions 1) Monitoring QA by the delta-H method is useful in assessing the hemodynamic response to elective VA intervention. 2) Mean QA post was similar to the highest recorded mean QA before intervention. 3) Mean ΔQA was related to mean QA post and overall mean QA after intervention. 4) The HD effectiveness (Kt/V index) improved after intervention.

Randomized controlled trial of prophylactic repair of hemodialysis arteriovenous graft stenosis. Background Previous nonrandomized studies suggest that prophylactic repair of hemodialyisis arteriovenous (AV) graft stenosis reduces thrombosis rates and increases cumulative graft survival. The present study is a randomized trial comparing prophylactic repair of AV graft stenosis with repair at the time of thrombosis. Methods Sixty-four patients with elevated static venous pressure measured in an upper extremity AV graft were randomized to Intervention or Observation. Monthly static venous pressure/systolic blood pressure ratios (SVPR) were determined for all patients throughout the duration of study participation. Patients in the Intervention group underwent angiography and repair of identified stenoses if the monthly SVPR was elevated (≥0.4). Patients in the Observation group underwent stenosis repair only in the event of access thrombosis or clinical evidence of access dysfunction. The primary end point was access abandonment. Results Access abandonment occurred in 14 patients in the Intervention group and 14 patients in the Observation group during the 3.5-year study period. Time to access abandonment did not differ significantly between the treatment groups (hazard ratio for randomization to Intervention 1.75, 95% CI 0.80–3.82, P = 0.16). The proportion of patients with a thrombotic event was greater in the Observation group (72%) than in the Intervention group (44%) ( P = 0.04), but overall thrombosis rates were similar in the groups. Conclusion Compared with a strategy of observation and repair of accesses only in the event of thrombosis, prospective static venous pressure monitoring with prophylactic stenosis repair did not prolong graft survival.