Contemporary review of management techniques for cephalic arch stenosis in hemodialysis

The type of hemodialysis access and its preservation impact the quality of life and survival of patients undergoing hemodialysis. Vascular access complications are among the top causes of morbidity, hospitalization, and catheter use, with significant economic burden. Poor maturation and stenosis continue to be key impediments to upper arm arteriovenous fistula feasibility. Cephalic arch is a common location for vascular access dysfunction due to its distinctive anatomy, complex valves, and biochemical alterations attributable to renal failure. Understanding cephalic arch stenosis is critical due to its high prevalence and treatment failure. The appropriate management option is highly debatable and mostly dependent on patient characteristics and interventionist's preference. Current options include, percutaneous transluminal balloon angioplasty, stent grafts, bare metal stents, cutting balloon angioplasty, endovascular banding, and surgical procedures. This article discusses the etiologies of cephalic arch stenosis as well as currents trends in management including endovascular and surgical options.

Dual outflow upper arm arteriovenous fistula: An effective technique to prevent cephalic arch stenosis

Cephalic arch stenosis (CAS) is critical point to maintain functional arteriovenous fistula (AVF) in patients undergoing hemodialysis with brachio-cephalic AVFs. In this study, we aimed to determine the effectiveness of dual outflow (cephalic and basilic veins) as a surgical method to prevent CAS. Between July 2016 and December 2019, 369 patients underwent upper arm AVF creation. Among them the 251 patients were enrolled in this retrospective study. Two hundred seven underwent brachio-cephalic arteriovenous fistula (BCAVF) and 44 underwent brachio-cephalicbasilic arteriovenous fistula (BCBAVF). From the 251 patients, diabetes mellitus (66.7% vs 36.4%, P < .001) and hypertension (91.3% vs 75%, P = .002) were more common in the patient group who underwent BCAVF surgery; however, the difference in volume flow to the fistula did not differ between the 2 groups. CAS (30.4% vs 9.1%, P = .004) and fistula occlusion (15.9% vs 4.5%, P = .048) were likely to occur in the BCAVF group. The primary patency rates at 12 months were 74.3% and 86.4% for the BCAVFs and BCBAVFs, respectively (P = .075). The primary-assisted patency rates at 12 months were 87.0% for BCAVFs and 93.2% for BCBAVFs, respectively (P = .145). Secondary patency rates at 12 months were 92.2% for BCAVFs and 93.2% for BCBAVFs, respectively (P = .023). Compared to BCAVF, traditional upper arm AVF, upper arm AVF with cephalic and basilic vein dual drainage can be optimal surgical method to preventing CAS.

Cephalic arch stenosis in the arteriovenous fistula: A retrospective analysis of predisposing factors

BACKGROUND

Cephalic Arch Stenosis (CAS) is a frequently observed complication in brachiocephalic and radiocephalic arteriovenous fistulae (AVF) associated with high morbidity and healthcare expenditure. The predisposing factors and preventative strategies for CAS remain unclear. Our aim was to examine predisposing factors for CAS development in the AVF.

METHODS

A retrospective case-control study was performed at Gold University Coast Hospital on patients with AVFs created from 2009 to 2018 with ⩾18 months follow-up. CAS was defined as a >50% narrowing on angiographic assessment with clinically significant symptoms (dialysis dysfunction, arm swelling, prolonged bleeding after access).

RESULTS

About 187 patients with AVF were included in the analysis (36 brachiocephalic, 151 radiocephalic). CAS developed in 22 of 36 (61%) of brachiocephalic AVF and 9 of 151 (6%) of radiocephalic AVFs. Brachiocephalic AVF were ⩾12 times more likely to develop CAS than radiocephalic AVF (Hazard Ratio (HR) 12.7, 95% CI [5.6-28.3], p < 0.001). Each 1 mL/min increase in flow rate through the AVF, correlated with a 0.07% increase in the probability of development of CAS (HR 1.0007, 95% CI [1.0001-1.0012], p = 0.011). Brachiocephalic AVFs with CAS were associated with a higher number of interventional procedures per access-year compared with their non-CAS counterparts (Median [Interquartile range]: 1.76 [0.74, 3.97] vs 0.41 [0.27, 0.67], p = 0.003).

CONCLUSION

Brachiocephalic AVF with higher access flow rates are more likely to develop CAS and earlier than radiocephalic AVF, and in a dose dependent fashion. AVF flow rate is a major factor in CAS development within brachiocephalic AVF and has potential utility in surveillance thresholds for prophylactic blood flow reduction procedures. AVFs with CAS are associated with a greater number of interventional procedures per access-year, heralding higher patient morbidity and healthcare expenditure. Further prospective studies will help define an AVF access flow rate threshold in the implementation of prophylactic strategies for CAS.

Swing segment stenosis: An unresolved challenge

The native arteriovenous fistula is considered the gold standard among all dialysis access options. Compared with alternatives such as grafts and central venous catheters, their use is associated with a lower risk of infective and thrombotic complications. This leads to better patient outcomes and reduced healthcare-associated costs. Recognizing these advantages, there is a global drive to increase the creation and use of such fistulas in hemodialysis patients. Swing segment stenosis is a common problem encountered with the creation and use of these fistulas that can hurt their maturation and longevity. A "swing segment" in an arteriovenous fistula is defined as a segment of vein that pursues a sharp, curved course. Due to poorly understood reasons, these swing segments tend to develop stenotic lesions that are extremely challenging to treat. This review aims to provide an overview of the pathophysiology, incidence, management, and prevention of these swing segment lesions. We believe that such knowledge will be useful for clinicians who deal with dialysis access creation and maintenance.

ASDIN white paper: Management of cephalic arch stenosis endorsed by the American Society of Diagnostic and Interventional Nephrology

Brachiocephalic arteriovenous fistulas (AVF) makeup approximately one third of prevalent dialysis vascular accesses. The most common cause of malfunction with this access is cephalic arch stenosis (CAS). The accepted requirement for treatment of a venous stenosis lesion is ⩾50% stenosis associated with hemodynamically abnormalities. However, the correlation between percentage stenosis and a clinically significant decrease in access blood flow (Qa) is low. The critical parameter is the absolute minimal luminal diameter (MLD) of the lesion. This is the parameter that exerts the key restrictive effect on Qa and results in hemodynamic and functional implications for the access. CAS is the result of low wall shear stress (WSS) resulting from the effects of increased blood flow and the unique anatomical configuration of the CAS. Decrease in WSS has a linear relationship to increased blood flow velocity and neointimal hyperplasia exhibits an inverse relationship with WSS. The result is a stenotic lesion. The presence of downstream venous stenosis causes an inflow-outflow mismatch resulting in increased pressure within the access. Qa in this situation may be decreased, increased, or within a normal range. Over time, the increased intraluminal pressure can result in marked aneurysmal changes within the AVF, difficulties with cannulation and the dialysis treatment, and ultimately, increasing risk of access thrombosis. Complete characterization of the lesion both hemodynamically and anatomically should be the first step in developing a strategy for management. This requires both access flow measurement and angiographic imaging. Patients with CAS present a relatively broad spectrum as relates to both of these parameters. These data should be used to determine whether primary treatment of CAS should be directed toward the anatomical lesion (small MLD and low Qa) or the pathophysiology (large MLD and high Qa).

The geometry of arteriovenous fistulas using endothelial nitric oxide synthase mouse models

BACKGROUND

Arteriovenous fistula (AVF) maturation failure is a significant clinical problem in the hemodialysis population. Geometric parameters of human AVFs were associated with AVF development, but causative studies are lacking. We characterized mouse AVF geometry using endothelial nitric oxide synthase (NOS3) mouse models.

METHODS

Carotid-jugular AVFs were created in NOS3 overexpression (OE), knockout (KO), and wild type (WT) mice. At 7 and 21 days postcreation, black-blood magnetic resonance images of AVFs were acquired and used to build three-dimensional reconstructions of AVF lumens. We used these reconstructions to calculate the lumen area, lumen centerline, and centerline-derived parameters: anastomosis angle, tortuosity, nonplanarity angle, and location of maximal distance between the feeding artery and AVF vein. Inter- and intrauser variabilities were also determined.

RESULTS

When all mice were considered, increased minimum AVF venous lumen area was accompanied by increased venous tortuosity and increased distance between the artery and vein, with both remaining in-plane with the anastomosis. At day 7, the lumen area of AVFs from all strains was 1.5- to 2.5-fold larger than native veins. Furthermore, at day 21, AVF lumen in NOS3 OE (4.04±1.43 mm2) was significantly larger than KO (2.74±1.34 mm2) (P<0.001) and WT (2.94±1.30 mm2) mice (p<0.001). At day 21, the location of maximal artery-vein distance on the vein was further away from the anastomosis in OE (4.49±0.66 mm) than KO (2.87±0.38 mm) (p=0.001). Other geometric parameters were not significantly different between mouse strains or time points. Inter- and intrauser variabilities were small, indicating the reliability and reproducibility of our protocol.

CONCLUSIONS

Our study presents a detailed characterization of mouse AVF geometry, and a robust protocol for future mechanistic studies to investigate the role of molecular pathways in AVF geometry. Identifying a geometry related to desired AVF remodeling can help inform surgery to enhance AVF maturation.

A cohort study showing correspondence of low wall shear stress and cephalic arch stenosis in brachiocephalic arteriovenous fistula access

BACKGROUND

A brachiocephalic fistula is frequently placed for hemodialysis; unfortunately, cephalic arch stenosis commonly develops, leading to failure. We hypothesized that a contribution to brachiocephalic fistula failure is low wall shear stress resulting in neointimal hyperplasia leading to venous stenosis. The objective of this investigation is to determine correspondence of low wall shear stress and the development of cephalic arch stenosis.

METHODS

Forty subjects receiving hemodialysis with a primary brachiocephalic fistula access were followed from time of placement for 3 years or until cephalic arch stenosis. Venogram, Doppler, and viscosity were performed at time of fistula maturation, annually for 3 years or to time of cephalic arch stenosis. Computational hemodynamics modeling was performed to determine location and percent low wall shear stress in the arch. The relationship between wall shear stress at time of maturation and location of cephalic arch stenosis were estimated by correlating computational modeling and quadrant location of cephalic arch stenosis.

RESULTS

In total, 32 subjects developed cephalic arch stenosis with 26 displaying correspondence between location of low wall shear stress at time of maturation and subsequent cephalic arch stenosis, whereas 6 subjects did not (p = 0.0015). Most subjects with correspondence had low wall shear stress areas evident in greater than 20% of the arch (p = 0.0006). Low wall shear stress was associated with a higher risk of cephalic arch stenosis in the 23-to-45 age group (p = 0.0029).

CONCLUSIONS

The presence and magnitude of low wall shear stress in the cephalic arch is a factor associated with development of cephalic arch stenosis in patients with brachiocephalic fistula. Attenuation of low wall shear stress at time of maturation may help prevent the development of cephalic arch stenosis which is difficult to treat once it develops.

Restoration of wall shear stress in the cephalic vein during extreme hemodynamics

The surgical creation of an artery-vein connection via a Brachicephalic fistula (BCF) in patients with end stage renal disease (ESRD) provides a unique opportunity to study blood vessel response mechanisms to extreme hemodynamic conditions in relatively short timeframes. After BCF creation, the flow rate in the vein increases by an order of magnitude leading to separated flows and corresponding abnormally low, or negative, wall shear stress (WSS) in the curved arch segment of the cephalic vein. Locations of abnormally low WSS are shown to correlate with development of neointimal hyperplasia (NH) and subsequent stenosis. It is found that the stenosis, prior to a surgical intervention, restores the normal physiological WSS in the vein. As a result, this investigation provides evidence that the adaptation principle, known to apply in the arterial system, is also valid in the venous system. A novel graphical method is developed that combines clinical and computational data to assist in interpreting these physiological mechanisms including adaptation that lead to changes in vein geometry over time.

Spanish Clinical Guidelines on Vascular Access for Haemodialysis

Vascular access for haemodialysis is key in renal patients both due to its associated morbidity and mortality and due to its impact on quality of life. The process, from the creation and maintenance of vascular access to the treatment of its complications, represents a challenge when it comes to decision-making, due to the complexity of the existing disease and the diversity of the specialities involved. With a view to finding a common approach, the Spanish Multidisciplinary Group on Vascular Access (GEMAV), which includes experts from the five scientific societies involved (nephrology [S.E.N.], vascular surgery [SEACV], vascular and interventional radiology [SERAM-SERVEI], infectious diseases [SEIMC] and nephrology nursing [SEDEN]), along with the methodological support of the Cochrane Center, has updated the Guidelines on Vascular Access for Haemodialysis, published in 2005. These guidelines maintain a similar structure, in that they review the evidence without compromising the educational aspects. However, on one hand, they provide an update to methodology development following the guidelines of the GRADE system in order to translate this systematic review of evidence into recommendations that facilitate decision-making in routine clinical practice, and, on the other hand, the guidelines establish quality indicators which make it possible to monitor the quality of healthcare.

A Report of Two Cases of Hazards Associated with High Flow Arteriovenous Fistula in ESRD Patients

High flow arteriovenous fistulas are a common clinical entity affecting patients with end-stage renal failure receiving hemodialysis. Given the difficulty in predicting who will develop a high flow arteriovenous fistula the exact prevalence is unclear. We present two cases of patients with high flow arteriovenous fistula that developed clinical cardiac failure at a time point after the fistula was placed with findings of significant cephalic arch stenosis. Both patients required treatment of cephalic arch stenosis with balloon angioplasty with subsequent surgical aneurism resection. Accurate and timely diagnosis of high flow arteriovenous hemodynamics by prospective monitoring of volumetric flow and cardiac function is required to halt this process prior to cardiac compromise.

Surgical Treatment of Cephalic Arch Problems in Arteriovenous Fistulas: A Center Experience

BACKGROUND

Cephalic arch problems, mainly stenosis, are a common cause of arteriovenous fistulas (AVFs) failure, and the most effective treatment is yet to be clearly defined. Restenosis usually occurs soon, and multiple interventions become necessary to maintain patency and functionality. The authors present the experience of their center with cephalic vein transposition in a group of patients with different problems involving the cephalic arch.

METHODS

After consultation of the medical records, an observational retrospective analysis was performed to evaluate the outcomes of surgical treatment in cephalic arch problems of AVFs treated at the author's center between January 2013 and December 2015. The considered outcomes were endovascular intervention rate, thrombosis rate, and primary and secondary patencies.

RESULTS

Seven patients were treated by venovenostomy with transposition of the cephalic arch and anastomosis to the axillary vein. The average patient age was 72 years (59-81), and most patients were female (71%) and diabetic (71%). All accesses were brachiocephalic AVFs with a mean duration of 4 years (1-7). The underlying problems were intrinsic cephalic arch stenosis (n = 5), entrapment of the cephalic vein (n = 1), and clinically significant vein tortuosity at the cephalic arch (n = 1). These last 2 problems conducted to a surgical approach as first-line therapy instead of endovascular intervention, the initial treatment in the other 5 cases (all with high-pressure balloons, with cutting balloon in one case). Previous thrombotic episodes were reported in 57% of the patients. The mean access flow before surgical intervention was 425 mL/min (350-1,500). No complications related with the surgical procedure were reported. One patient underwent surgical thrombectomy after AVF thrombosis, followed by transposition of the vein. In another case, a simultaneous flow reduction was performed. Most of the patients on dialysis (5/6) used the AVF after surgery. After a mean follow-up period of 9 months (1-22), surgical treatment was associated with a reduction in endovascular intervention rate (1.9 interventions per patient-year presurgery versus 0.4 postsurgery; P < 0.05) and thrombosis rate (0.93 thrombotic episodes per patient-year presurgery versus 0.17 postsurgery; P < 0.05). The problems leading to endovascular reintervention were as follows: new venous anastomosis stenosis (57%), axillary vein stenosis (29%), and swing-point stenosis (14%). Primary and secondary patencies at 6 months were 57% and 71%, respectively.

CONCLUSIONS

In this group of patients with cephalic arch problems and multiple previous procedures, surgical treatment was associated with a reduction in endovascular intervention and thrombosis rate but did not avoid reintervention. Facing the complexity and multiplicity of the cephalic arch complications, treatment should be individually decided.

Cephalic Arch Stenosis in Autogenous Brachiocephalic Hemodialysis Fistulas: Results of Cutting Balloon Angioplasty

Purpose

Cephalic arch stenosis is a known cause of hemodialysis access failure in patients with brachiocephalic fistulas (BCFs). Outcomes of endovascular treatment are affected by resistance of the stenosis to balloon dilation, a high vein rupture rate and the development of early restenosis. The purpose of this retrospective study was to report outcomes after cutting balloon angioplasty (CBA) of cephalic arch stenosis.

Methods

In our vascular access database we identified 74 dysfunctional BcFs of which 30 (41%) were caused by cephalic arch stenosis. Seventeen fistulas in 17 patients (13 males and four females; median age 62 yrs; range 52–86) were treated with CBA (June 2005 to January 2008). Twenty-five procedures were performed. In 15 procedures, a cutting balloon was used alone and in 10 procedures CBA was followed by standard or high-pressure balloon angioplasty. Restenosis rates were calculated and patency rates were estimated with the Kaplan-Meier method.

Results

Primary patency rates (±SEE) at 3, 6, 12 and 15 months were 94% (±6%), 81% (±10%), 38% (±14%) and 22% (±15%), respectively. Assisted primary patency rates (±SEE) at the same intervals were 100% (±0%), 94% (±6%), 77% (±12%) and 63% (±13%), respectively. The mean interval between radiological interventions was 13 months (SD=8) and the mean number of interventions required per patient-year of dialysis was 0.9.

Conclusion

Treatment of cephalic arch stenosis with CBA did not improve patency compared to published results of conventional PTA, but our results indicate that CBA may lower the frequency of required re-interventions.

Angiography of Hemodialysis Fistulas and Grafts

Angiography of the dialysis access is an important procedure in dealing with dialysis arteriovenous access (AVA) dysfunction. It is an integral part and the initiating procedure for all the interventional procedures performed for the management and salvage of dialysis AVA. The performance of this procedure and normal dialysis access-related anatomy including anatomical variants are discussed. In addition, pathology commonly encountered in association with the anatomy is reviewed.

Comparison of Post-Creation Procedures and Costs between Surgical and an Endovascular Approach to Arteriovenous Fistula Creation

Introduction

Due to early and late failures that may occur with surgically created hemodialysis arteriovenous fistulas (SAVF), post-creation procedures are commonly required to facilitate AVF maturation and maintain patency. This study compared AVF post-creation procedures and their associated costs in patients with SAVF to patients with a new endovascularly created AVF (endoAVF).

Methods

A 5% random sample from Medicare Standard Analytical Files was abstracted to determine post- creation procedures and associated costs for SAVF created from 2011 to 2013. Medicare enrollment during the 6 months prior to and after the AVF creation was required. Patients’ follow-up inpatient, outpatient, and physician claims were used to identify post-creation procedures and to estimate average procedure costs. Comparative procedural information on endoAVF was obtained from the Novel Endovascular Access Trial (NEAT).

Results

Of 3764 Medicare SAVF patients, 60 successfully matched to endoAVF patients using 1:1 propensity score matching of baseline demographic and clinical characteristics. The total post-creation procedural event rate within 1 year was lower for endoAVF patients (0.59 per patient-year) compared to the matched SAVF cohort (3.43 per patient-year; p<0.05). In the endoAVF cohort, event rates of angioplasty, thrombectomy, revision, catheter placement, subsequent arteriovenous graft (AVG), new SAVF, and vascular access-related infection were all significantly lower than in the SAVF cohort. The average first year cost per patient-year associated with post-creation procedures was estimated at US$11,240 USD lower for endoAVF than for SAVF.

Conclusions

Compared to patients with SAVF, patients with endoAVF required fewer post-creation procedures and had lower associated mean costs within the first year.

A Systematic Review and Meta-Analysis of Circulating Biomarkers Associated with Failure of Arteriovenous Fistulae for Haemodialysis

BACKGROUND

Arteriovenous fistula (AVF) failure is a significant cause of morbidity and expense in patients on maintenance haemodialysis (HD). Circulating biomarkers could be valuable in detecting patients at risk of AVF failure and may identify targets to improve AVF outcome. Currently there is little consensus on the relationship between circulating biomarkers and AVF failure. The aim of this systematic review was to identify circulating biomarkers associated with AVF failure.

METHODS

Studies evaluating the association between circulating biomarkers and the presence or risk of AVF failure were systematically identified from the MEDLINE, EMBASE and Cochrane Library databases. No restrictions on the type of study were imposed. Concentrations of circulating biomarkers of routine HD patients with and without AVF failure were recorded and meta-analyses were performed on biomarkers that were assessed in three or more studies with a composite population of at least 100 participants. Biomarker concentrations were synthesized into inverse-variance random-effects models to calculate standardized mean differences (SMD) and 95% confidence intervals (CI).

RESULTS

Thirteen studies comprising a combined population of 1512 participants were included after screening 2835 unique abstracts. These studies collectively investigated 48 biomarkers, predominantly circulating molecules which were assessed as part of routine clinical care. Meta-analysis was performed on twelve eligible biomarkers. No significant association between any of the assessed biomarkers and AVF failure was observed.

CONCLUSION

This paper is the first systematic review of biomarkers associated with AVF failure. Our results suggest that blood markers currently assessed do not identify an at-risk AVF. Further, rigorously designed studies assessing biological plausible biomarkers are needed to clarify whether assessment of circulating markers can be of any clinical value. PROSPERO registration number CRD42016033845.

Increased Inlet Blood Flow Velocity Predicts Low Wall Shear Stress in the Cephalic Arch of Patients with Brachiocephalic Fistula Access

Background

An autogenous arteriovenous fistula is the optimal vascular access for hemodialysis. In the case of brachiocephalic fistula, cephalic arch stenosis commonly develops leading to access failure. We have hypothesized that a contribution to fistula failure is low wall shear stress resulting from post-fistula creation hemodynamic changes that occur in the cephalic arch.

Methods

Twenty-two subjects with advanced renal failure had brachiocephalic fistulae placed. The following procedures were performed at mapping (pre-operative) and at fistula maturation (8–32 weeks post-operative): venogram, Doppler to measure venous blood flow velocity, and whole blood viscosity. Geometric and computational modeling was performed to determine wall shear stress and other geometric parameters. The relationship between hemodynamic parameters and clinical findings was examined using univariate analysis and linear regression.

Results

The percent low wall shear stress was linearly related to the increase in blood flow velocity (p < 0.01). This relationship was more significant in non-diabetic patients (p < 0.01) than diabetic patients. The change in global measures of arch curvature and asymmetry also evolve with time to maturation (p < 0.05).

Conclusions

The curvature and hemodynamic changes during fistula maturation increase the percentage of low wall shear stress regions within the cephalic arch. Low wall shear stress may contribute to subsequent neointimal hyperplasia and resultant cephalic arch stenosis. If this hypothesis remains tenable with further studies, ways of protecting the arch through control of blood flow velocity may need to be developed.

Hemodynamic and biologic determinates of arteriovenous fistula outcomes in renal failure patients

The outcome of patients with end-stage renal disease on hemodialysis depends on a functioning vascular access. Although a variety of access options are available, the arteriovenous fistula remains the best vascular access. Unfortunately the success rate of mature fistula use remains poor. The creation of an arteriovenous fistula is followed by altered hemodynamic and biological changes that may result in neointimal hyperplasia and eventual venous stenosis. This review provides an overview of these changes and the needed research to provide a long lasting vascular access and hence improve outcomes for patients with end-stage renal disease.

Central venous occlusion mimics carotid cavernous fistula: a case report and review of the literature

A patient presented with signs and symptoms of a left carotid cavernous fistula (CCF). Computed tomography angiography confirmed filling of the cavernous sinus in the arterial phase. Cerebral digital subtraction angiography demonstrated no evidence of CCF. The workup, diagnosis, and treatment of this patient are discussed, and the literature is reviewed.

Central Transposition of the Cephalic Vein in Patients with Brachiocephalic Arteriovenous Fistula and Cephalic Arch Stenosis

Purpose:

Our study aims to evaluate to evaluate clinical outcomes after cephalic vein transposition (CVT) to the axilla in patients with brachiocephalic arteriovenous fistula (BC-AVF) and cephalic arch stenosis (CAS).

Materials and Methods:

Hospital records of 13 patients (median age, 61 years; males, 54%) who received CVT to the proximal basilic/axillary vein due to either dysfunction (n=2) or thrombosis (n=11) between January 2010 and February 2014 were retrospectively reviewed.

Results:

Operation was performed under local anesthesia in all cases. There was no technical failure. Concomitant inflow procedure (banding or aneurysmorrhaphy) was performed in 5 patients (38%). During follow-up (1 to 50 months, median 17 months), 3 patients died with functioning AVF and one was successfully transplanted. Two patients suffered from recurrent symptomatic stenosis of AVF and received percutaneous balloon angioplasty. Another 2 patients experienced AVF occlusion treated with interposition graft and manual fragmentation. Overall primary, assisted primary, and secondary patency rates were 77.5%, 92.3%, and 100% at 6 months and 66.1%, 92.3%, and 100% at 1 year, respectively.

Conclusion:

Although most patients presented with BC-AVF occlusion, technical success and access patency rates after CVT were favorable compared with historical data for interventional treatment. CVT should be considered as an appropriate option in selected patients with CAS.

Cephalic Arch Stenosis in Dialysis Patients: Review of Clinical Relevance, Anatomy, Current Theories on Etiology and Management

Arteriovenous hemodialysis fistulas (AVFs) serve as a lifeline for many individuals with end-stage renal failure. A common cause of AVF failure is cephalic arch stenosis. Its high prevalence compounded with its resistance to treatment makes cephalic arch stenosis important to understand. Proposed etiologies include altered flow in a fistulized cephalic vein, external compression by fascia, the unique morphology of the cephalic arch, large number of valves in the cephalic outflow tract and biochemical changes that accompany renal failure. Management options are also in debate and include angioplasty, cutting balloon angioplasty, bare metal stents, stent grafts and surgical techniques including flow reduction with minimally invasive banding as well as more invasive venovenostomy with transposition surgeries for refractory cases. In this review, the evidence for the clinical relevance of cephalic arch stenosis, its etiology and management are summarized.

Challenges and management of high-flow arteriovenous fistulae

The Kidney Dialysis Outcomes Quality Initiative and Fistula First Initiative have embraced the arteriovenous fistula as the gold standard for hemodialysis accesses. Despite this status, fistulae are fraught with complex issues ranging from a high primary failure rate to high flow resulting in increased cardiovascular morbidity. It is important not to overlook the insidious peril of a hyperfunctioning access that may actively promote cardiac overload, cardiopulmonary recirculation, rapid access growth with aneurysm enlargement, recurrent venous stenosis resulting in access failure, and inflow/outflow mismatch. Once recognized, flow can and should be reduced to mitigate these and other negative effects.

Surgical Treatment of Cephalic Arch Stenosis by Central Transposition of the Cephalic Vein

Purpose

After creation of a brachiocephalic (BC) arteriovenous fistula (AVF), stenosis of the cephalic vein close to its junction with the axillary vein (cephalic arch stenosis, CAS) can develop. Flow impairment and access thrombosis are the consequences, sometimes complicated by prestenotic aneurysm of the cephalic vein. We here report our experience with cephalic vein transposition (CVT) for CAS.

Methods

From March 2007 through February 2012, symptomatic CAS was detected in 25 patients (13 female) with either dysfunction (n=14) or thrombosis (n=11) of their BC AVF. All were treated by CVT: the vein was ligated and cut distally to the stenotic segment, then tunneled subcutaneously to the medial aspect of the upper arm and anastomosed to the proximal brachial or basilic vein in an end-to-side fashion. Simultaneous thrombectomy of the cephalic vein was performed in 11 patients and aneurysmorrhaphy in 9. In addition, one patient had a proximal new AV anastomosis, another angioplasty of an in-stent restenosis of the access-draining subclavian vein.

Results

After CVT, two acute complications (8%) occurred: access thrombosis (one) and bleeding (one). During follow-up (1 to 54 months, median 13 months, 34.5 patient-years), six patients died with functioning AVF, three were successfully transplanted. Primary (secondary) 1-year patency was 79% (90%), with a reintervention rate of 0.1/patient/year.

Conclusions

Primary 1-year access patency rates after CVT compare favorably with those after interventional treatment, and reintervention rates are lower. Frequently occurring prestenotic aneurysms could be repaired simultaneously. CVT should therefore be regarded as the treatment of choice for CAS.

Access Flow Reduction and Recurrent Symptomatic Cephalic Arch Stenosis in Brachiocephalic Hemodialysis Arteriovenous Fistulas

Background

Recurrent cephalic arch stenosis (CAS) has been linked to high flow and has a high rate of recurrence following angioplasty. This study investigates the effectiveness of access flow reduction in decreasing rapidly recurrent symptomatic CAS.

Methods

A retrospective study of patient records from February 2005 to April 2009 was conducted. Patients with brachiocephalic fistulas who had undergone two or more instances of cephalic arch angioplasty within 3 months, and thereafter underwent flow reduction via banding of the access inflow (n=33) were included. A before-and-after analysis was conducted: the rates of cephalic arch angioplasty were calculated for each patient before and after the banding procedure, and compared via a paired t-test.

Results

At 3, 6, and 12 months, the cephalic arch primary lesion patency was 91%, 76%, and 57%. The cephalic arch intervention rate was reduced from 3.34 to 0.9 per access-year (t=7.74, p<.001). The average follow-up time was 14.5 months (range, 4.8–32).

Conclusion

Flow reduction of a brachiocephalic arteriovenous hemodialysis fistula may effectively diminish the incidence of symptomatic CAS.