Autogenous Arteriovenous Fistula Creation Research Articles

The feasibility of small-caliber veins for autogenous arteriovenous fistula creation: A single-center retrospective study.

Autogenous arteriovenous fistula (AVF) is recommended as the first choice for hemodialysis vascular access. A small-caliber vein is one of the independent risk factors for AVF maturation and patency. However, the specific threshold is still unclear, making it difficult to accurately determine whether these vessels are suitable for AVF creation. This is a single-center retrospective study. Patients who underwent AVF creation in our medical center between January 2020 and September 2022 and satisfied the eligibility criteria were included in this retrospective study. Logistic regression analysis was performed to identify risk factors for functional maturation and additional intervention. The optimal cutoff value was determined based on the receiver operating curve (ROC) and the Youden index. Kaplan-Meier analysis was utilized in further patency rate comparisons. A total of 125 forearm AVFs were created in 121 patients with end-stage renal disease (ESRD). The mean age was 53.88 ± 15.10 years. Preoperative vascular Doppler ultrasound (DUS) was conducted and recorded in 106 cases (84.80%). The mean targeted artery and vein diameters were 2.17 ± 0.54 and 1.71 ± 0.75 mm, respectively. Small-caliber vein is the risk factor for functional maturation failure (OR = 0.256, 95%CI [0.06-0.75], p = 0.033) and additional intervention (OR = 0.306, 95% CI [0.09-0.78], p = 0.031). The optimal cutoff value is 1.35 mm (augmented) when specificity and sensitivity reach 80 and 63.7%, respectively. The AVFs with a vein diameter of more than 1.35 mm (augmented) showed higher patency rates (p < 0.01). After comprehensive DUS evaluation, intraoperative hydrodilation, postoperative active exercise and intensive DUS detection, and application of balloon-assisted maturation, if necessary, using a vein more than 1.35 mm (augmented), could achieve satisfactory functional maturation and postoperative patency in AVF formation.

A Murine Model of Hemodialysis Access-related Hand Dysfunction.

Chronic kidney disease is a major public health problem, and the prevalence of end-stage renal disease (ESRD) requiring chronic renal replacement therapies such as hemodialysis continues to increase. Autogenous arteriovenous fistula (AVF) placement remains a primary vascular access option for ESRD patients. Unfortunately, approximately half of the hemodialysis patients experience dialysis access-related hand dysfunction (ARHD), ranging from subtle paresthesia to digital gangrene. Notably, the underlying biologic drivers responsible for ARHD are poorly understood, and no adequate animal model exists to elucidate the mechanisms and/or develop novel therapeutics for the prevention/treatment of ARHD. Herein, we describe a new mouse model in which an AVF is created between the left common iliac artery and vein, thereby facilitating the assessment of limb pathophysiology. The microsurgery includes vessel isolation, longitudinal venotomy, creation of arteriovenous anastomosis, and venous reconstruction. Sham surgeries include all the critical steps except for AVF creation. Iliac AVF placement results in clinically relevant alterations in central hemodynamics, peripheral ischemia, and impairments in hindlimb neuromotor performance. This novel preclinical AVF model provides a useful platform that recapitulates common neuromotor perturbations reported by hemodialysis patients, allowing researchers to investigate the mechanisms of ARHD pathophysiology and test potential therapeutics.

Salvage of infected autogenous arteriovenous fistulas, is it possible?

Infection in autogenous arteriovenous fistulas (AVFs) is a critical situation in patients with end stage renal disease (ESRD) that can lead to life threatening rupture or septicemia. To date, no standard guidelines regarding the surgical repair of the infected AVFs is available. To evaluate the safety and efficacy of the surgical repair in the infected autogenous AVFs. This prospective study involved 64 ESRD patients who presented with infected autogenous AVFs. Repair of the infected autogenous AVFs was done in 50 cases, while ligation was needed in the other 14 cases. Aneurysmorrhaphy was done in the 26 cases of puncture site infection over venous aneurysms. In 20 cases of AVFs with anastomotic disruption, higher recreation in a proximal clean field (AVF loop anastomosis) was performed, while abscess drainage was done in the remaining four cases presented with non-communicating abscess over the vein. The 14 cases of ligated AVFs included 9 cases of infected ruptured AVFs with active bleeding and 4 cases with non-reconstructable puncture site infection. After 1 year of follow up, 41 cases (82%) of the repaired AVFs (n = 50) remained patent and functioning as re-infection occurred in 9 cases. Six tunneled permanent catheters were implanted in the 14 cases with ligated AVFs, while the remaining 8 cases had new AVFs established (7 cases of them retained patent AVFs during the follow up period). Surgical repair of the infected AVFs is an effective procedure that achieves many goals, such as saving patients' lives, maintaining the patency of the native fistula, and avoidance of creation of new AVFs in another site with exhaustion the available veins.

Outcomes of arteriovenous fistula creation: A Jordanian experience.

The arteriovenous fistula is considered the preferred hemodialysis access due to its lower complication rate and longer patency. The aim of this study is to report the outcomes of arteriovenous fistula creation and to study the predictive factors for these outcomes. This is a retrospective study of all patients who underwent autogenous arteriovenous fistula creation procedure by a single surgeon during the period from October 2011 till December 2017. All the procedures were performed at an academic referral center by a single surgeon. All patients who underwent arteriovenous fistula creation in the upper limb during the study period were included. All patients were diagnosed with end-stage renal disease and referred for arteriovenous fistula creation either before or after initiating hemodialysis. Data were collected from the patients' charts. The primary outcomes were the primary failure and secondary patency rates. Secondary outcome was to find the factors associated with decreased patency. The Kaplan-Meier curve with the log-rank test was used to describe the patency while univariate and multivariate analyses were done to the factors considered relevant to the patency. The total number of procedures was 291; of which, 18 were lost to follow-up. The primary failure rate was 12%. Secondary patency rate at 1 and 5 years was 79% and 53%, respectively. Diabetes mellitus and fistulae placed on right side were associated with decreased patency. The primary failure rate was relatively low in this study but the long-term functionality of the arteriovenous fistulae needs to be improved.

PC132. Making the Most of the Median Antebrachial Vein in Hemodialysis Access

There is a continued need for improved strategies to create and to maintain autogenous arteriovenous fistulas (AVFs). The autogenous radial-cephalic AVF is the widely recognized first choice, and brachial-cephalic AVFs are often the second choice. There is variable superficial venous anatomy nearing the antecubital fossa. The median antebrachial vein has dual outflow to both the cephalic and basilic veins. An AVF using the median antebrachial vein (MAV-AVF) is a less commonly performed procedure that affords unique benefits. Between August 2016 and December 2018, there were 14 autogenous MAV-AVFs created at our institution. The proximal radial artery was used as inflow for 12 of these AVFs, and the brachial artery was used for the remaining 2. During the study period, 14 patients underwent AVF creation. One patient experienced a postoperative deatah unrelated to surgery. Of the remaining 13 patients who underwent MAV-AVF creation, 30-day patency was 100%. One patient sustained thrombosis of the fistula 27 months after the index operation, and five patients required subsequent reoperations. Two patients were able to access the fistula using one needle in the cephalic vein and a second needle in the basilic vein immediately after fistula maturation. These patients later underwent basilic vein superficialization because stenosis of the cephalic vein precluded access 12 and 18 months after the index operation. One patient required ligation of the basilic vein for failure of fistula maturation due to competing outflow veins. Two patients underwent ligation of the basilic vein to treat ischemic steal syndrome. All five of these patients were able to continue to access the AVF after reoperation. This series demonstrates that an autogenous AVF using median antebrachial vein as outflow is a viable option for permanent hemodialysis access. The dual outflow of the MAV-AVF has unique benefits and challenges. Both the cephalic and basilic veins can be used for hemodialysis access. If the basilic vein is the dominant outflow, superficialization may be required. Patients with MAV-AVFs can also have complications of high-outflow fistulas, which are easily treated with ligation of one of the outflow veins while maintaining viability of the AVF. Ligation of competing outflow veins is occasionally required to promote fistula maturation. The MAV-AVF is a valuable tool in the vascular surgeon’s armamentarium, with the unique outflow anatomy allowing multiple possible revisions to prolong its life before requiring progression to a more proximal fistula or synthetic graft.

The Role of Preoperative Duplex Ultrasound Vessel Mapping in Determining Primary Failure of Pediatric Hemodialysis Arteriovenous Fistula

The autogenous arteriovenous fistula (AVF) is the preferred vascular access for pediatric and adult patients on chronic hemodialysis (HD). However, the prevalent rate of AVF use in children remains low in the United States. Duplex ultrasonography (DUS) of arm vessels is an essential step in the planning of AVF creation in adults, but its use in children is not described in much detail. In this retrospective study, we examined the role of preoperative DUS in children and adolescents who underwent AVF creation at a single large pediatric hospital, from 2008 to 2017. In addition, we sought to determine the potential risk factors for primary failure (PF), which was defined as the inability to use the AVF for at least a sustained 6-week period either due to thrombosis or any other reasons. We created 67 AVFs in 57 patients (34 male; 60%). The overall PF was 16% (11/67), and higher in cephalic AVF (10/40, 25%) compared to basilic (1/27, 3.7%), P = .04. The median maturation time was longer for basilic compared to cephalic AVF (105±47 vs. 88±38 days, respectively, P = .006). The size of the juxta-anastomotic vein and artery on preoperative DUS was not significantly different in cephalic versus basilic AVFs. However, the median diameter of the outflow vein was significantly smaller in the cephalic compared to basilic AVF (3.4 mm vs. 4.2 mm, P = .042). In addition, the outflow vein size was the only preoperative factor found to be significant as possible predictor for PF on univariable analysis. The results of this study show that the PF rate and maturation time for AVFs created in children and adolescents are comparable to adults, with the routine use of preoperative DUS. We postulate that vessel selection for AVF in the pediatric population should take into consideration the size of the vein at the outflow (and not just at the anastomosis).

Technique to Avoid Hemodialysis Catheter in Patients with Failing Aneurysmal Arteriovenous Fistula by Creating a Concomitant New Arteriovenous Fistula

Autogenous arteriovenous fistula (AVF) is the primary recommended access for hemodialysis. Long-term use will not uncommonly result in AVF aneurysmal degeneration. Aneurysm-associated complications encompass pain, skin ulceration, infection, thrombosis, cannulation difficulties, and life-threatening bleeding. Various methods to repair aneurysmal AVFs have been described. However, there may be circumstances when this is not possible and require insertion of a temporary hemodialysis catheter (HDC) until a new arteriovenous access is created. We describe a case series of creating a new simultaneous AVF while continuing to use the primary failing aneurysmal AVF to avoid placement of an HDC. Once the new AVF becomes operational, the primary aneurysmal AVF can be abandoned. Six patients underwent simultaneous new AVF creation, 4 ipsilateral, and 2 contralateral. None of the patients developed symptomatic steal syndrome or congestive heart failure. Five of 6 patients had successful usage of the new AVF, and subsequently underwent ligation and excision of the aneurysmal AVF, thus avoiding a temporary HDC. Close monitoring for skin compromise and bleeding in the aneurysmal AVF is recommended while the new AVF matures.

Postoperative day 1 access blood flow and resistive index can predict patency in distal forearm arteriovenous fistula.

Early access failure is an important complication of autogenous arteriovenous fistulas (AVFs). We prospectively monitored patients who underwent AVF creation using ultrasonography. Color flow imaging was used to assess access blood flow in patients undergoing creation of a new AVF in the distal forearm preoperatively and at 1 day and 1 week postoperatively. We measured the flow volume (FV) and resistive index (RI) of the brachial artery, and the internal diameter of the brachial artery and outflow vein. The primary outcome was the primary patency of the AVF without percutaneous angioplasty (PTA) or surgical revision 40 days after access creation. We recruited 35 patients with newly created AVFs (men, 21; mean age, 73 years). Within one day of operation, the overall FV increased from 62 to 352 mL/min (p<0.0001) while the overall RI decreased from 1.0 to 0.63 (p<0.001). Five patients required PTA or surgical revision (intervention group [IG]), whereas 30 patients did not (non-intervention group [NIG]). The FV increased while the RI decreased from day 1 to week 1 in the NIG, but not in the IG (p<0.0001). The diameter of the brachial artery and outflow vein significantly increased in the NIG at 1 week. The FV of 235 mL/min and RI of 0.63 at 1 day were the thresholds for predicting early fistula failure. Access FV and RI at 1 day after AVF creation can predict primary patency and help plan intervention.

Forearm autogenous arteriovenous fistula creation using the operative microscope magnification in adult patients: A single centre observational study

Forearm autogenous arteriovenous fistula creation using the operative microscope magnification in adult patients: A single centre observational study

Multiple preoperative and intraoperative factors predict early fistula thrombosis in the Hemodialysis Fistula Maturation Study

Early thrombosis (ET) contributes to autogenous arteriovenous fistula (AVF) failure. We studied patients undergoing AVF placement in the Hemodialysis Fistula Maturation Study, a prospective, observational cohort study, using a nested case-control analysis to identify preoperative and intraoperative predictors of ET. ET cases were compared with controls, who were matched for gender, age, diabetes, dialysis status, and surgeon fistula volume. ET was defined as thrombosis diagnosed by physical examination or ultrasound within 18 days of AVF creation. Conditional logistic regression models were fit to identify risk factors for ET. Thirty-two ET cases (5.3%) occurred among 602 study participants; 198 controls were matched. ET was associated with female gender (odds ratio [OR], 2.75; 95% confidence interval [CI], 1.19-6.38; P = .018), fistula location (forearm vs upper arm; OR, 2.76; 95% CI, 1.05-7.23; P = .039), feeding artery (radial vs brachial; OR, 2.64; 95% CI, 1.03-6.77; P = .043) and arterial diameter (OR, 1.52; 95% CI, 1.02-2.26; P = .039, per mm smaller). The draining vein diameter was nonlinearly associated with ET, with highest risk in 2- to 3-mm veins. Surprisingly, ET risk was lower in diabetics (OR, 0.19; 95% CI, 0.07-0.47; P = .0004), lower with less nitroglycerin-mediated brachial artery dilation (OR, 0.42; 95% CI, 0.20-1.92; P = .029 for each 10% lower) and higher with lower carotid-femoral pulse wave velocity (OR, 1.49; 95% CI, 1.02-2.20; P = .041, for each m/s lower). Intraoperative protamine use was associated with a higher ET risk (OR, 3.26; 95% CI, 1.28-∞; P = .038). Surgeon's intraoperative perceptions were associated with ET: surgeons' greater concern about maturation success (likely, marginal, unlikely) was associated with higher thrombosis risk (OR, 8.09; 95% CI, 4.03-∞; P < .0001, per category change), as were absence vs presence of intraoperative thrill (OR, 21.0; 95% CI, 5.07-∞; P = .0001) and surgeons' reported frustration during surgery (OR, 6.85; 95% CI, 2.70-∞; P = .0004). Decreased extent of intraoperative thrill (proximal, mid or distal third of the forearm or upper arm, based on AVF placement) was also associated with ET (OR, 2.91; 95% CI, 1.31-∞; P = .007, per diminished level). Oral antithrombotic medication use was not significantly associated with ET. ET was found to be associated with female gender, forearm AVF, smaller arterial size, draining vein diameter of 2 to 3 mm, and protamine use. Paradoxically, diabetes and stiff, noncompliant feeding arteries were associated with a lower frequency of ET. Absent or attenuated intraoperative thrill, and both surgeon frustration and concern about successful maturation during surgery, were correlated strongly with ET.

Effect of brachial plexus block-driven vascular access planning on primary distal arteriovenous fistula recruitment and outcomes

Hemodialysis vascular accesses (VAs) are traditionally planned based on the nondominant upper extremity preoperative physical and sonographic vascular findings. Clinical guidelines advocate the use of the most suitably distended vein in the most distal location. Brachial plexus block (BPB), through its sympathectomy-like effect, promotes vasodilation and can thus further optimize vein recruitment and operative strategy. However, studies on its role in driving primary distal autogenous arteriovenous fistula (AVF) placement are limited. We therefore evaluated a traditional approach of clinic-based VA planning against an on-table sonography-guided strategy under BPB. This was a prospective observational study involving 110 consecutive end-stage renal disease multiethnic Asian patients referred for primary VA creation under BPB after preoperative venous mapping. Cases were grouped according to whether there was a preset operative plan for radial cephalic (RC) or brachial cephalic (BC) AVF creation based on artery and vein >2mm and >2.5mm size criteria respectively (group A) or vein size or length were suboptimal (2-2.5mm and<5cm respectively), thus precluding any operative plan till after BPB (group B). Group B also included cases with a preset VA plan but that subsequently underwent an on-table change in operative plan as a result of more favorable distal vein dilation post-BPB. RC AVF recruitment, maturation, and patency rates were compared in the two groups over a 1-year follow up. One hundred RC and BC AVF were available for analysis after excluding brachial AVFs and grafts: 41 in group A and 59 in group B. Twenty one (51%) primary RC AVFs were created according to a preset preoperative plan compared with 37 (63%) based upon on-table planning or plan modification (P > .05). Satisfactory post-BPB forearm vasodilation resulted in 44% of 36 plans for BC being changed to RC AVFs. RC AVF 6-week hemodynamic maturation and 3-month functional maturation in group A vs B were 48% vs 60% and 69% vs 57%, respectively (P > .05). One-year primary and secondary patency rates were 57% vs 50% and 73% vs 87%, respectively (log rank >.05). Outcomes of RC AVFs in group B were not inferior to those of BC AVFs. On-table BPB-driven VA planning and plan modification strategy contribute to considerable AVF recruitment but do not lead to significantly better distal AVF prevalence or outcomes over the traditional approach. An adequately powered randomized controlled study is, however, warranted to better assess the long-term clinical and cost benefits of such a strategy.

RR14. The Role of Routine Duplex Surveillance in AVF Maturation: A Prospective, Randomized Trial

To increase the usage of the autogenous arteriovenous fistula (AVF), close postoperative surveillance by an experienced physician is recommended, but currently there is no agreed protocol. This prospective, randomized, controlled study tested whether aggressive surveillance with routine duplex ultrasound and active intervention could enhance maturation rate of autogenous AVF. The study enrolled 150 patients undergoing autogenous AVF creation. Immediately after the operation, patients were randomly assigned to a group that received a postoperative visit at 2 and 4 weeks with physical examination only (control group, n = 76) or to a group that received a postoperative visit at 2 and 4 weeks with routine duplex ultrasound and physical examination (duplex group, n = 74). Patients of the control group had selective duplex examination only when an abnormality was detected during the physical examination. The physical examination was done by an experienced vascular surgeon, and the duplex examination was conducted by a certified registered vascular technologist. Both groups had a duplex examination at postoperative visit at week 8, and maturation rates were compared. Maturation was defined as successful first use before postoperative week 8 or venous rim flow >500 mL/min at the final duplex examination. In addition, we also sought to determine the patient and anatomic variables predictive of fistula maturation. Among 150 patients, 118 patients (control group, n = 59; duplex group, n = 59) were included in the final analysis. Eleven patients from the control group and 10 patients from the duplex group had undergone surgical or percutaneous intervention for abnormalities detected during the postoperative visits. Overall maturation rate was 80.6% at postoperative week 8, and there was no significant difference between the duplex group and the control group (44 of 59 [74.6%] vs 51 of 59 [86.4%], P = .104). Factors positively associated with maturation were the presence of coronary artery disease (P = .008), diabetes as the etiology of the renal failure (P = .004), use of antiplatelet or anticoagulant medications (P = .030), and preoperative cephalic vein diameter (P = .008). Postoperative surveillance with routine duplex ultrasound has no significant advantage over surveillance with physical examination by experienced vascular surgeon in terms of autogenous AVF maturation.

Adipose phenotype predicts early human autogenous arteriovenous hemodialysis remodeling

Substantial proportions of autogenous arteriovenous fistulas (AVFs) for hemodialysis access fail to mature for unclear reasons. AVFs develop in a large mass of surrounding adipose tissue that is increasingly recognized as an active participant in the vascular response to injury via paracrine and endocrine mechanisms. We thus hypothesized that baseline phenotypic characteristics of the adipose tissue juxtaposed to the developing AVF associate with subsequent inward or outward vein wall remodeling. Clinical data and subcutaneous adipose tissue were collected from 22 consented patients undergoing AVF creation. Tissue was assayed (protein levels) for interleukin (IL)-6, IL-8, leptin, tumor necrosis factor-α, monocyte chemoattractant protein-1 (MCP-1), resistin, and adiponectin. Vein dimensions were acquired by duplex ultrasound imaging, preoperatively and at 4 to 6 weeks postoperatively, 1 cm cephalad to the arteriovenous anastomosis, which is the most common location of AVF stenosis). The vein at the assayed location outwardly remodeled 55.7% on average (median before, 3.7 mm; median after, 4.7 mm; P = .005). The preoperative vein diameter failed to correlate with postoperative size at the point of assay (R = 0.31; P = .155) unless two outliers were excluded (R = 0.64; P = .002). After removal of the same outliers, the correlation coefficient between venous diameter change (preoperative vs postoperative) and IL-8, tumor necrosis factor-α, MCP-1, resistin, and adiponectin was -0.49, -0.79, -0.66, -0.64, and -0.69, respectively (P < .05). Postoperative AVF flow volume correlated with MCP-1 (R = -0.53; P < .05) and adiponectin (R = -0.47; P < .05). These data reveal a novel relationship between local adipose phenotype and the eventual venous wall response to hemodynamic perturbation in humans. The predictive value of these mediators generally equaled or exceeded that of preoperative vein size. Beyond providing mechanistic insights into vascular wall adaptations due to flow perturbations, this discovery suggests that strategies focused on altering adipose tissue biology may improve AVF maturation.

Surgeon's Intraoperative Assessments During Autogenous Arteriovenous Fistula Creation Strongly Correlate With Early Fistula Thrombosis

Surgeon's Intraoperative Assessments During Autogenous Arteriovenous Fistula Creation Strongly Correlate With Early Fistula Thrombosis

Autologous surgical reconstruction for true venous hemodialysis access aneurysms--techniques and results.

Due to their relatively low complication rates autogenous arteriovenous fistulas (AVFs) are the preferred access for hemodialysis. In long-standing AVF, however, aneurysmatic degeneration of the fistula vein can develop. Several treatment options have been published. We evaluated our experience with autologous surgical reconstruction in patients with AVF aneurysms in order to assess complication and patency rates. Demographics and comorbidities of all patients operated on for true AVF aneurysms in our institution, during a 7-year period, were reviewed. Access function and surgical outcomes were evaluated with pre- and postoperative Doppler ultrasonography. Patient survival, primary and secondary access patency rates are presented. From April 2006 through March 2013, 31 patients presented with access-associated upper extremity venous aneurysms. The mean time from AVF creation to aneurysm formation was 4.9±3.6 years. The most frequent indication for surgery was aneurysm-associated stenosis (n=16) followed by high flow (n=9), complete thrombosis (n=3) and uncontrolled bleeding (n=3). All patients had autologous reconstructions: 5 resections with end-to-end anastomosis and 26 aneurysmorrhaphies. Overall patient survival at 1 and 2 years was 89% and 84%, respectively. The primary (secondary) patency rates at 6 mo, 1 and 2 years were 87%, 81% and 81% (96%, 96% and 90%), respectively. Autologous surgical reconstruction is feasible in the majority of AVF aneurysms. It preserves fistula function and--in contrast to graft interposition and endovascular repair--keeps the advantages of an autogenous access: low complication and high patency rates.

8:00 AM; Abstract; No. 28 - Safety and efficacy of percutaneous autogenous arteriovenous fistula creation with the TVA FLEX system: expanded results beyond the pilot study

for catheter-directed thrombolysis (CDT) in iliac vein compression syndrome (IVCS) patients with deep venous thrombosis (DVT) and to propose image-based criteria for CDT. Materials and Methods: The institutional review board approved this retrospective study and waived informed consent. This study initially enrolled 201 consecutive patients treated in our interventional suite for DVT from January 2001 to June 2013. Afterwards, 48 IVCS patients who underwent pre-procedural CT venography, CDT with stenting, and follow-up imaging were analyzed. To identify significant predictors of 6-month patency, CT venography was evaluated with Fisher’s exact test and logistic regression analyses. Based on the results, image-based criteria were established and compared to the current symptom duration-based approach by ROC curve analyses and the McNemar test. Results: Recoiling of external iliac vein (EIV) diameter (o 120%) (hazard ratio [HR] 1⁄4 28.652, p 1⁄4 .0073) and severe rim enhancement (HR 1⁄4 20.545, p 1⁄4 .0155) were significant risk factors for venous occlusion within 6 months of CDT. The dual-parameter image-based criteria were significantly superior to the current symptom duration-based approach in terms of area under the curve value and specificity. With a 2-point cutoff, the proposed criteria demonstrated a sensitivity of 66.7%, specificity of 100.0%, and diagnostic accuracy of 92.9% for identifying non-responders of CDT. Conclusion: The image-based criteria may be useful in assessing CDT prognoses in IVCS patients, particularly to identify non-responders who demonstrate recoiling of EIV diameter and rim enhancement on CT venography.

Hand Ischemia Associated With Dialysis Vascular Access: An Individualized Access Flow‐based Approach to Therapy

With the rise in the median age of hemodialysis patients, the increasing numbers of patients with multiple risk factors for vascular disease, and the efforts being made to increase the creation of autogenous arteriovenous fistulas (AVFs), dialysis access-related steal syndrome (DASS) has become a growing problem. This syndrome, caused by arterial insufficiency distal to the arteriovenous access due to diversion of blood into the access, is a potentially devastating complication. It is crucial that physicians who manage hemodialysis patients and perform vascular access procedures have a comprehensive understanding of the pathophysiology, symptoms, diagnostic maneuvers, and treatment options for DASS. The goals of management must be twofold-relieve the ischemia and preserve the access. The choice of any intervention, if such is necessary, should be based upon the clinical features presented by that individual patient; the clinical condition and prognosis of the patient, stage of the disease, location of the arterial anastomosis, and the level of blood flow within the access. This review presents information that supports an individualized, physiologic approach to this condition.

Impact of Routine Use of a Tourniquet during Preoperative Vein Mapping on the Diameter of Arm Veins and Creation of Functional Arteriovenous Fistulas

Purpose —To examine the impact of tourniquet usage during preoperative vein mapping on diameter of arm veins and functionality of autogenous arteriovenous fistulas (AVF) thus created. Methods —A total of 160 patients in need of hemodialysis access underwent segmental upper-extremity duplex ultrasonography. Vein measurements were performed with and without application of an upper arm tourniquet. Criteria for AVF creation included superficial veins with diameter ≥3.0 mm and continuity with proximal superficial veins. Group I had patients with veins with diameter ≥3.0 mm attained without use of a tourniquet whereas Group II had patients with vein diameters ≥3.0 mm achieved with a tourniquet. Clinical outcomes were compared between the two groups. Results —Of the 160 patients, 114 underwent placement of an upper extremity AVF, whereas the remaining underwent placement of an AV graft or peritoneal dialysis catheter. Of these, 87 patients were in Group I and 27 in group II. The primary outcome was defined as a functional AVF within 6 months of surgery. In Group I, almost two of every three fistulas created were successful, resulting in a failure rate of 37.5%. In contrast, only one out of every six AVFs in Group II was successful resulting in a failure rate of 86%. Conclusion —The use of tourniquet results in a greater number of patients qualifying for AVF creation. However, AVFs created using vein diameter obtained from the application of a tourniquet have much greater rates of failure compared with AVFs created by using a vein of similar diameter but without a tourniquet.

Risk Factors Predicting the Successful Function and Use of Autogenous Arteriovenous Fistulae for Hemodialysis

For patients with end-stage renal failure hemodialysis with an autogenous arteriovenous fistula (AVF) has proven to be the ideal vascular access. The aim of this study is to discover potential predictors of a well-functioning hemodialysis fistula. From December 2009 to March 2011, 80 patients undergoing first time AVF creation were enrolled in our retrospective study. We analyzed pre- and postoperative vessel diameters and flow characteristics gained by duplex ultrasonography (DUS) and intraoperative ultrasound transit-time flow measurements regarding intraoperative blood flow and pulsatility index (PI). Follow-up was defined until the end of the first month with regular hemodialysis, 10 weeks after AVF creation. We performed statistical analyses by employing Spearman correlation, t test, analysis of variance, χ2 test, and receiver operating characteristics (ROC). At the end of the follow-up, 62 patients (78%) featured functioning AVFs and 18 patients (22%) featured nonfunctioning AVFs. Factors influencing AVF function were radial artery diameter (χ2 = 5.23, p = 0.02), intraoperative flow (χ2 = 7.09, p = 0.01), intraoperative PI (χ2 = 6.5, p = 0.01), and postoperative flow (χ2 = 16.29, p = 0.01). According to the ROC analyses, we could develop cut-off values for predicting an ideal AVF function: radial artery diameter more than 2.3 mm, cephalic vein diameter more than 2.7 mm, intraoperative mean flow more than 113 mL/min, PI less than 1.4, and postoperative mean flow more than 160 mL/min. Intraoperative ultrasound transit-time flow measurements gained at surgery and postoperative follow-up with DUS can help identify AVFs that are unlikely to function and therefore need early intervention.

Intra-Operative Factors Predicting 1-Month Arteriovenous Fistula Thrombosis

The aim of this study is to determine clinical and ultrasound intra-operative factors related to 1-month autogenous arteriovenous fistula (AVF) thrombosis in end-stage renal failure patients. A prospective study was designed, including AVF performed between October 2009 and May 2010. Patient characteristics and intra-operative measurements (clinical and ultrasound findings in both artery and vein: diameters, peak-systolic, end-diastolic and mean velocities, flow and resistance index) were recorded. At 1-month follow-up, AVF primary patency was analyzed. Stepwise logistic regression and ROC curves of the resulting test were used. 111 autogenous end-to-side AVF (44 radiocephalic, 45 brachiocephalic, 22 brachiobasilic) in 101 patients were performed. One-month primary patency rate was 84.7%. Intra-operative absence of bruit following skin closure could predict 1-month AVF thrombosis (70.6% sensitivity and 80.9% specificity, better than absence of thrill: 35.3% and 87.2%). However, logistic regression identified intra-operative end-diastolic velocity in the proximal feeding artery after AVF creation (EDV) as the best independent predictor of 1-month AVF thrombosis (OR=1.072, 95%CI 1.036-1.109; 76.5% sensitivity and 84.0% specificity for EDV<24.5 cm/s). This is a slight improvement on isolated clinical findings, but nevertheless a low positive predictive value (46.4%) is attained. Prediction of AVF thrombosis with intra-operative ultrasound measurements (proximal artery EDV under 24.5 cm/s) can slightly improve isolated clinical findings, helping to establish an intra-operative criterion to review AVF and increase surgical efficiency, assuming a relatively low positive predictive value.