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.

Arteriovenous Fistulas and Their Characteristic Sites of Stenosis.

OBJECTIVE: In the United States, more than 250,000 patients with end-stage renal disease are dialyzed through arteriovenous fistulas (AVFs). The three most common AVFs are the radiocephalic fistula, the brachiocephalic fistula, and the brachial artery-to-transposed basilic vein fistula. Although many potential access site stenoses can and do occur within any given fistula, each fistula has a characteristic site of stenosis. This article will discuss the characteristic site of stenosis for each type of fistula including the effects of stenosis at that site on fistula function, and their treatment. CONCLUSION: The characteristic sites of stenosis in AVFs used for dialysis share in common significant angulation, which likely causes stenosis by leading to turbulent flow and intimal injury. While balloon dilation is considered first-line therapy, further interventions such as stent placement or surgical revision are sometimes needed to treat these recalcitrant areas of stenosis.

Cephalic arch stenosis: angioplasty to preserve a brachiocephalic fistula or new brachiobasilic fistula? A cost-effectiveness study.

BACKGROUND: Our aim was to evaluate the cost-effectiveness of repeat angioplasty versus new brachiobasilic fistula (BBF) in patients with symptomatic cephalic arch stenosis (CAS). METHODS: Patients presenting with symptomatic CAS (n = 22) underwent angioplasty. They were compared to patients undergoing BBF creation (n = 51). Primary outcomes were functional primary arteriovenous fistulae patency at 3, 6 and 12 months. Data were collected on number of interventions, alternative accesses and hospital days for access-related complications. Quality of life was assessed using Kidney Disease Quality of Life-36 scores. Decision tree, Monte Carlo simulation and sensitivity analysis permitted cost-utility analysis. Healthcare costs were derived from Department of Health figures and are presented as cost (£)/patient/year, cost/access preserved and cost/quality of life-adjusted year (QALY) for each of the treatment strategies. RESULTS: Functional primary patency rates at 3, 6, 12 months were 87.5%, 81% and 43% for repeated angioplasty and 78%, 63% and 41% for BBF. The angioplasty cohort required 1.64 ± 0.23 angioplasties/patient and 0.64 ± 0.34 lines/patient. BBF required 0.36 ± 0.12 angioplasties/patient and 1.2 ± 0.2 lines/patient. Patients in the BBF cohort spent an additional 0.9 days/year in hospital due to access-related complications. Mean cost/patient/year in the angioplasty group was £5247.72/patient/year versus £3807.55/patient/year in the BBF cohort. Mean cost per access saved was £11,544.98 (angioplasty) versus £4979.10 (BBF). Average cost per QALY was £13,809.79 (angioplasty) versus £10,878.72 per QALY (BBF). CONCLUSIONS: CAS poses a difficult management problem with poor outcomes from conventional angioplasty. Optimal management will depend on patient factors, local outcomes and expertise, but consideration should be given to creation of a new BBF as a cost-effective means to manage this difficult problem.

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.

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).

Treatment for cephalic arch stenosis with cephalic vein to external jugular vein bridging graft.

AIM: Percutaneous transluminal angioplasty or cephalic vein transposition to the axillary vein is mainly used for treatment of cephalic arch stenosis, a common complication of brachiocephalic fistulas. However, the results of such interventions have been disappointing. METHODS: We used a polytetrafluoroethylene prosthesis with a 6 mm diameter to bridge the cephalic vein and the ipsilateral external jugular vein, and successfully created a new drainage outlet and established immediate restoration of flow through brachiocephalic fistulas. RESULTS: This surgery allowed the cephalic venous arch and subclavian vein, which are vulnerable to stenosis, to be bypassed altogether and the puncture segment could be elongated by about 20 cm. CONCLUSION: It is a safe and effective alternative to traditional methods of treatment for cephalic arche stenosis.

Outcomes of endovascular treatment for stenosis occurring after cephalic vein transposition and graft interposition.

OBJECTIVE: To evaluate the outcome of endovascular treatment after surgical treatment for cephalic arch stenosis (CAS) in the brachiocephalic fistula (BCF) and to analyze the factors influencing patency. METHODS: We conducted a retrospective review of patients undergoing cephalic vein transposition (CVT) or graft interposition (GIP) for CAS from January 1, 2017, to December 31, 2019. A total of 73 patients with restenosis were included in this study. Patients were classified into cephalic transposition (BCF-CVT) (n = 49) and graft interposition (BCF-GIP) (n = 24) groups. We calculated the postintervention primary and secondary patency of endovascular treatment by using the Kaplan-Meier analysis and analyzed variables associated with loss of postintervention patency. RESULTS: Six-month and 12-month postintervention primary patency rates of endovascular treatment for restenosis were 56.7% and 15.6% and secondary patency rates were 89.7% and 72.1%, respectively. In the BCF-CVT group, 6-month and 12-month postintervention primary patency was 56.8% and 17.6% and secondary patency was 93.3% and 79.4%, respectively. In the BCF-GIP group, 6-month and 12-month postintervention primary patency was 56.5% and 8.7% and secondary patency was 85.7% and 56.3%, respectively. There was no significant difference in postintervention primary patency between the two groups (P = .79). However, the BCF-CVT group demonstrated higher postintervention secondary patency (P = .034). The BCF-GIP group had a higher number of stenosis sites (P < .01). There was no significant predictor of reduced postintervention primary patency. The only adverse variable of postintervention secondary patency was BCF-GIP (hazard ratio, 3.14; 95% CI, 1.06-9.34; P < .05). CONCLUSIONS: Endovascular treatment is still the acceptable option for stenosis occurring after surgical treatment for CAS. CVT provides higher postintervention secondary patency than GIP.

Clinical predictors of recurrent cephalic arch stenosis and impact of the access flow reduction on the patency rate.

OBJECTIVE: Despite the widespread use of conventional percutaneous transluminal angioplasty (PTA), recurrence of cephalic arch stenosis (CAS), and low patency rate after PTA remain challenging problem. We aimed to identify the clinical predictors of recurrence of CAS and evaluate the effect of the access flow reduction on the fistula patency rate in patients with recurrent CAS. METHODS: In 1118 angiographies of 220 patients with CAS, access circuit patency rates after PTA and potential clinical predictors of recurrence of CAS were assessed. The effect of the banding procedure was evaluated in terms of post-interventional primary patency rate, and the number of interventions per access-year. RESULTS: At 3, 6, and 12 months after the first PTA on CAS, the post-interventional access circuit primary patency rates were 68.8%, 40.5%, and 25.1%, respectively. High CV to CA ratio (the ratio of the maximal diameter of the distal cephalic vein to the diameter of the cephalic arch) (Hazard ratio (HR), 1.437; 95% confidence interval (CI), 1.036-1.992) and involvement of the proximal segment of cephalic arch (HR, 1.828; 95% CI, 1.194-2.801) were significant predictors of recurrent CAS. For those with recurrent CAS (>3 times/year) and an access flow rate >1.5 L/minute, endovascular banding procedure was performed. The banding procedure significantly reduced the number of interventions per access-year (t = 3.299, p = 0.005 and t = 2.989, p = 0.007, respectively). Post-interventional access circuit primary patency rate after banding was significantly higher than that before banding (p = 0.01). CONCLUSIONS: High CV to CA ratio and involvement of the proximal segment of the cephalic arch are independent clinical predictors of recurrent CAS. Endovascular banding might delay recurrence of CAS in patients with high CV to CA ratio and high access flow.

Study protocol for a Prospective, Randomized controlled trial of stEnt graft and Drug-coated bAlloon Treatment for cephalic arch stenOsis in dysfunctional arteRio-venous fistulas (PREDATOR).

BACKGROUND: Treatment of cephalic arch stenosis (CAS) is associated with high risk of failure and complications. Although stent-graft (SG) placement has improved patency rates, stent edge restenosis has been raised as a potential limiting factor for SG usage in CAS. This study aims to evaluate the safety and efficacy of combining stent graft placement with paclitaxel-coated balloon (PCB) angioplasty versus PCB alone in the treatment of CAS. METHODS: This is an investigator-initiated, prospective, international, multicenter, open-label, randomized control clinical trial that plans to recruit 80 patients, who require fistuloplasty from dysfunctional arteriovenous fistula (AVF) from CAS. Eligible participants are randomly assigned to receive treatment with SG and PCB or PCB alone in a 1:1 ratio post-angioplasty (n = 40 in each arm). Randomization is stratified by de novo or recurrent lesion, and the participants are followed up for 1 year. The primary endpoints of the study are target lesion primary patency (TLPP) and access circuit primary patency (ACPP) rates at 6-months. The secondary endpoints are TLPP and ACPP at 3- and 12-month; target lesion and access circuit assisted primary and secondary patency rates at 3, 6, and 12-months and the total number of interventions; complication rate; and cost-effectiveness. DISCUSSION: This study will evaluate the clinical efficacy and safety of combination SG and PCB implantation compared to PCB alone in the treatment of CAS for hemodialysis patients.

Treatment of cephalic arch stenosis in dysfunctional arteriovenous fistulas with paclitaxel-coated versus conventional balloon angioplasty.

BACKGROUND: Treatment of cephalic arch stenosis (CAS) with standard plain old balloon angioplasty (POBA) in dysfunctional arteriovenous fistulas (AVF), is associated with early re-stenosis and higher failure rates compared to other lesions. Paclitaxel-coated balloons (PCB) may improve patency rates. This is a retrospective cohort study. Patients who underwent POBA or PCB for CAS over a 3-year period were included. Outcomes compared were circuit primary patency rates (patency from index procedure to next intervention), circuit primary assisted-patency rates (patency from index procedure to thrombosis), and target lesion (CAS) patency rates (stenosis > 50%) at 3, 6 and 12 months. RESULTS: Ninety-one patients were included. Sixty-five (71.4%) had POBA, while 26 (28.6%) had PCB angioplasty. There were 62 (68.1%) de-novo lesions. CAS was the only lesion that needed treatment in 24 (26.4%) patients. Circuit primary patency rates for POBA versus PCB groups were 76.2% vs. 60% (p = 0.21), 43.5% vs. 36% (p = 0.69) and 22% vs. 9.1% (p = 0.22) at 3, 6 and 12-months respectively. Circuit assisted-primary patency rates were 93.7% vs. 92% (p = 1.00), 87.1% vs. 80% (p = 0.51) and 76.3% vs. 81.8% (p = 0.77), whilst CAS target lesion intervention-free patency rates were 79.4% vs. 68% (p = 0.40), 51.6% vs. 52% (p = 1.00) and 33.9% vs. 22.7% (p = 0.49) at 3, 6 and 12-months respectively. Estimated mean time to target lesion intervention was 215 ± 183.2 days for POBA and 225 ± 186.6 days for PCB (p = 0.20). CONCLUSION: Treatment of CAS with PCB did not improve target lesion or circuit patency rates compared to POBA.

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.

Endovascular treatment of cephalic arch stenosis in brachiocephalic arteriovenous fistulas: A systematic review and meta-analysis.

PURPOSE: The aim of this study is to appraise the current literature on the endovascular management options and their outcomes of cephalic arch stenosis in the setting of a failing brachiocephalic fistula for hemodialysis. METHODS: A systematic search of the literature was performed using PubMed, Embase, and Google Scholar from January 2000 to December 2017 in accordance with the PRISMA guidelines to investigate the outcomes of endovascular management of cephalic arch stenosis. Data from randomized controlled trials and observational studies, published in the English language, were extracted to determine pooled proportion of primary and secondary patency, using a random-effects meta-analysis. Subgroup analyses of stent grafts, bare metal stents, and percutaneous transluminal angioplasty outcomes were performed. RESULTS: Of the 125 total studies, 11 were included for analysis by consensus. Overall, 457 patients were reviewed and analyzed for primary and secondary patency rates at 6 and 12 months post-treatment. There was significantly higher primary patency at both 6 and 12 months in the stent graft group compared to those who received bare metal stents or percutaneous transluminal angioplasty (relative risk = 0.30-0.31, relative risk = 0.34-0.59, respectively; p < 0.01). Higher secondary patency rates were noted in the bare metal stents cohort compared to the percutaneous transluminal angioplasty cohort at 12 months (relative risk = 0.17, 95% confidence interval = 0.07-0.26; p < 0.01). CONCLUSION: This study demonstrated a significant benefit in using stent grafts in cephalic arch stenosis compared to bare metal stents or percutaneous transluminal angioplasty with higher primary and secondary patency rates.

Cephalic Arch Stenosis: Location of Stenosis in Indian Hemodialysis Patients.

The cephalic vein is formed over the "anatomical snuff box" and joins the axillary vein just below the clavicular level. The definition of cephalic arch is varied. In the radiology literature, it is defined as the central perpendicular portion of the cephalic vein as it traverses the deltopectoral groove and joins the axillary vein. The possible etiologies of cephalic arch stenosis are numerous. This study aimed to identify patients with cephalic arch stenosis and to discern the domain site of stenosis. This is a retrospective case series of patients who had an arteriovenous fistula with dysfunction of access and ipsilateral upper-limb edema. The clinical features of the access dysfunction were strong pulse due to increased pressure, weak thrill due to poor proximal flow, high static pressure, or decreased dialysis efficiency. All these 25 patients underwent computed tomography (CT) angiogram. The CT angiographic findings revealed cephalic arch stenosis and stenosis in 13 patients (52%). domain IV was slightly more affected than other domains of cephalic arch.

The Role of Endovascular Stents in Dialysis Access Maintenance.

Vascular stenosis is most often the culprit behind hemodialysis vascular access dysfunction, and although percutaneous transluminal angioplasty remains the gold standard treatment for vascular stenosis, over the past decade the use of stents as a treatment option has been on the rise. Aside from the 2 Food and Drug Administration-approved stent grafts for the treatment of venous graft anastomosis stenosis, use of all other stents in vascular access dysfunction is off-label. Kidney Disease Outcomes Quality Initiative recommends limiting stent use to specific conditions, such as elastic lesions and recurrent stenosis; otherwise, additional adapted indications are in procedure-related complications, such as grade 2 and 3 hematomas. Published reports have shown the potential use of stents in a variety of conditions leading to vascular access dysfunction, such as venous graft anastomosis stenosis, cephalic arch stenosis, central venous stenosis, dialysis access aneurysmal elimination, cardiac implantable electronic device-induced stenosis, and thrombosed arteriovenous grafts. Although further research is needed for many of these conditions, evidence for recommendations has been clear in some; for instance, we know now that stents should be avoided along cannulation sites and should not be used in eliminating dialysis access aneurysms. In this review article, we evaluate the available evidence for the use of stents in each of the aforementioned conditions leading to hemodialysis vascular access dysfunctions.