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.

Cephalic arch stenosis in autologous hemodialysis fistula; to stent or not to stent? Long-term follow up

Background

A retrospective study of 44 patients with autologous arteriovenous fistula (AVF) presenting with cephalic arch stenosis was carried out. The aim is to assess the effectiveness of angioplasty and stenting in cephalic arch stenosis in autologous AVF in hemodialysis patients and also to assess the outcome of metal stents at this distinctive anatomical site. All patients were subjected to Doppler examination, where the stenotic lesion and the AVF flow volume were assessed prior to intervention. The follow-up period reached up to 57 months in some patients. All patients were under surveillance and were assessed for patency and flow volume. The primary and secondary stenosis-free rates were calculated. Re-intervention during the follow-up period was recorded.

Results

The technical success rate was 100%. Twenty-six patients had balloon angioplasty. Eighteen patients had primary and/or secondary stents inserted. The primary patency rate at 6 and 12 months for the balloon angioplasty group was 80% and 60% and for the stent group was 86% and 71%, respectively. The mean primary patency rate in balloon angioplasty patients was 12.9 months, while in the primary stented patients was 19.9 months. Twenty-six patients had secondary intervention. The average secondary patency rate for patients with balloon angioplasty was 25.5 months, while it was 33.6 months in the stented patients.

Conclusion

Cephalic arch angioplasty and stenting is an effective intervention increasing the longevity of the AVF that is crucial for hemodialysis patients. The use of metal stents whether bare metal stents or covered stents is safe and adds significant increase in patency rates.

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.

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 in brachiocephalic fistula and to analyze the factors influencing patency.

METHODS

We conducted a retrospective review of patients undergoing cephalic transposition (CVT) or graft interposition (GIP) for cephalic arch stenosis (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 BCF-CVT group, six month, and 12 month postintervention primary patency was 56.8% and 17.6% and secondary patency was 93.3% and 79.4%, respectively. In BCF-GIP group, six-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=0.79). However, BCF-CVT group demonstrated higher postintervention secondary patency (p=0.034). BCF-GIP group had a higher number of stenosis sites (p<0.01). 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 to 9.34, p <0.05).

CONCLUSION

Endovascular treatment is still the acceptable option for stenosis occurring after surgical treatment for CAS. CVT provides higher postintervention secondary patency than GIP.

Venous stent versus conventional stent for the treatment of central vein obstruction in hemodialysis patients: a retrospective study

BACKGROUND

Endovascular treatment is a first-line treatment for upper thoracic central vein obstruction (CVO). Few studies using bare venous stents (BVS) in CVO have been conducted.

PURPOSE

To evaluate the treatment performance of upper thoracic central vein stenosis between BVS and conventional bare stent (CBS) in hemodialysis patients.

METHODS

Hemodialysis patients with upper thoracic central vein obstruction who underwent endovascular treatment at the interventional unit of our institution from 1 January 2008 to 31 December 2018 were enrolled in the present study. CBS was used to treat central vein obstruction in 43 patients and BVS in 34 patients. We compared the primary patency rates and complications between the two stent types. P values < 0.05 were considered statistically significant.

RESULTS

The patient demographic data between the CBS and BVS groups were similar. The characteristics of the lesions, procedures, and complications were not significantly different between the two groups (P > 0.05). There were no statistically significant differences of primary patency rates at three and six months between the BVS and CBS groups (94.1% vs. 86.0% and 73.5% vs. 58.1%, respectively; P > 0.05). The primary patency rate at 12 months in the BVS group was significantly higher than that in the CBS group (61.8% vs. 32.6%; P = 0.008).

CONCLUSION

Endovascular treatment of central vein obstruction with BVS provided a higher primary patency rate at 12 months than CBS.

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.

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.

Site of service influence on stent use for hemodialysis access interventions

OBJECTIVE

With rising health care spending in the United States, the Centers for Medicare and Medicaid Services (CMS) in recent years attempted to use reimbursement rates to influence use of less expensive care sites for covered patients, such as ambulatory surgery centers (ASCs) and office-based laboratories (OBLs), in lieu of hospital service sites. It has been suggested that cost savings have not been realized because of more procedures being performed by physicians with ownership interests in nonhospital facilities. CMS adopted massive reimbursement changes for 2019 OBL and ASC-based procedures, which reduced dialysis access angioplasty reimbursement in the ASC setting by 50%, whereas facility reimbursement for stenting increased by 33% above prior levels. The clinical utility of adjunctive stenting in treating dialysis access stenosis remains controversial and highly discretionary. As a vascular group performing such procedures in both a hospital and nonhospital facility in which we have equity interest, we reviewed our use of stents in dialysis access procedures both in the hospital and in the ASC/OBL to determine whether site of service affected stent use.

METHODS

A retrospective review of a prospectively maintained database was performed from 2014 to 2018. All patients undergoing dialysis access angiography with angioplasty and adjunctive stent placement at our OBL (later ASC) and our primary hospital were included in the study.

RESULTS

There were 961 angioplasty or stent procedures performed for dialysis accesses between the two sites, 564 (58.7%) in the hospital setting and 397 (41.3%) at the OBL/ASC. There was a significant difference in race and age between the two sites, with younger, minority patients more frequently being treated in the hospital and older, white patients more likely to be treated in the ambulatory setting; 153 (27.1%) underwent adjunctive stent placement in the hospital and 127 (32.0%) in the ambulatory setting (P = .09).

CONCLUSIONS

Whereas financial incentives have not yet had an appreciable influence on stent use for dialysis access within previous reimbursement paradigms, the dramatic changes recently adopted by CMS may well alter this dynamic and could lead to substantially higher overall costs without proven clinical advantage. Interventionalists may be incentivized to add stents when performing balloon angioplasty in ASCs. With high failure and reintervention rates and increasingly expensive adjuncts (drug-coated balloons and stents, covered stents), the cost implications of attempts to incentivize interventionalists toward a specific type of procedure or site of care are substantial, and unintended negative consequences are likely to occur.

Thrombosed native hemodialysis fistulas: Technical and clinical outcomes of endovascular recanalization and factors influencing patency

Purpose:

To evaluate the technical and clinical results of endovascular recanalization of thrombosed native hemodialysis fistula and the factors influencing patency.

Methods:

A retrospective study was conducted with 73 patients who had thrombosed arteriovenous fistulas and were treated with endovascular methods. Patient characteristics, arteriovenous fistula-related characteristics, and endovascular procedures were analyzed. Technical and clinical results and patency rates were evaluated. The factors influencing patency were analyzed using a univariate and multivariate Cox proportional hazards model.

Results:

Technical and clinical success rates were 93% (68/73) and 85% (62/73), respectively. At 3, 6, and 12 months, the primary patency rates were 87.9%, 73.3%, and 64.8%; assisted primary patency rates were 89.2%, 78.6%, and 70.7%; and secondary patency rates were 90.8%, 87.2%, and 83.1%, respectively. Previous intervention and cephalic arch stenosis were risk factors for lower primary and assisted primary patency ( p < 0.05 for all). Cephalic arch stenosis was the only risk factor for lower secondary patency ( p < 0.05). No major complications associated with the procedures were noticed.

Conclusion:

Endovascular treatment was effective for the immediate recanalization of thrombosed arteriovenous fistula. In addition, previous intervention and cephalic arch stenosis were significantly related to lower arteriovenous fistula patency.

Recent developments in endovascular interventions to sustain vascular access patency in haemodialysis patients

There is amassed evidence regarding the use of endovascular procedures for the treatment of vascular access stenosis and thrombosis. A review was conducted based on available randomized trials, cohort studies and retrospective analyses published after 2000 on endovascular treatment of dysfunctional and thrombosed vascular access, with an aim to illustrate the available device and procedural options. The use of paclitaxel-coated balloons, cutting balloons and covered stents is described in the field of vascular access stenosis. The broad spectrum of available devices and endovascular declotting procedures ranging from thrombolysis to thrombectomy is also discussed. Overall, in this review we demonstrate the increasing role of endovascular procedures in vascular access treatment and the improved patency outcomes provided by the implementation of novel endovascular devices. Moreover, the improvement of post-intervention primary patency rates after endovascular declotting procedures and the shift to more thrombectomy-dependent procedures over time is also highlighted. In conclusion, endovascular treatment of dialysis access stenosis and thrombosis has an established role, owing to the implementation of sophisticated devices, allowing, when needed, the simultaneous treatment of thrombosis and the underlying stenosis.

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.

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 vein transposition is a durable approach to managing cephalic arch stenosis

INTRODUCTION

The proximal cephalic vein that enters the axillary vein (cephalic arch) is a common site of stenosis in patients with upper extremity arteriovenous fistulas for hemodialysis (HD). In this study, we present the outcomes of a series of cephalic vein transposition, to determine its utility in the setting of refractory arch stenosis.

METHODS

We conducted a retrospective review of patients undergoing cephalic vein transposition to manage refractory cephalic arch stenosis from January 1, 2008 to August 31, 2015. Demographics, past medical history, access history of the patients as well as procedural details of the surgery to the stenotic segment, patency of the access, and the need for subsequent interventions were recorded.

RESULTS

Twenty-three patients underwent a cephalic vein transposition during the study period. The patients undergoing cephalic transposition had their current access for an average of 3.0 ± 2.6 years and had an average of 2.3 ± 0.9 interventions on the access prior to the surgery. Complications from the surgery were uncommon (8.7%) and no patient required a temporary tunneled dialysis catheter. The re-intervention rate was 0.2 ± 0.2 interventions per patient per year. At two years, primary patency was 70.9% and cumulative patency was 94.7% for the patients with cephalic transposition.

CONCLUSIONS

Cephalic vein transposition is safe and effective treatment for cephalic arch stenosis without interrupting utilization of the access. The surgical approach to stenosis of the proximal cephalic vein is effective, requires minimal re-interventions, and should be considered for isolated, refractory cephalic arch stenosis in mature arteriovenous fistulas.

Results of Stent Graft Placement to Treat Cephalic Arch Stenosis in Hemodialysis Patients with Dysfunctional Brachiocephalic Arteriovenous Fistulas

PURPOSE

To determine effectiveness of the VIABAHN (W.L. Gore & Associates, Flagstaff, Arizona) stent graft to treat cephalic arch stenosis in patients with dysfunctional brachiocephalic arteriovenous fistulas after inadequate venoplasty response.

MATERIALS AND METHODS

Between 2012 and 2015, patients with failed venoplasty of symptomatic cephalic arch stenosis received a VIABAHN stent graft. Follow-up venography was performed at approximately 3, 6, and 12 months. Data were retrospectively analyzed with patency estimated using Kaplan-Meier and log-rank methodology. There were 39 patients included.

RESULTS

Technical and clinical success was 100%. Primary target lesion patency was 85% (95% confidence interval [CI], 69%-93%), 67% (95% CI, 50%-80%), and 42% (95% CI, 25%-57%) at 3, 6, and 12 months. There was no significant difference in patency with regard to sex or age (P = .8 and P = .6, respectively). Primary assisted patency was 95% (95% CI, 82%-99%) at 3, 6, and 12 months. Access circuit primary patency was 85% (95% CI, 69%-93%), 67% (95% CI, 50%-80%), and 42% (95% CI, 25%-57%) at 3, 6, and 12 months. There was no significant difference in patency between patients with the stent graft as the first treatment episode in the cephalic arch and those that had previous intervention at this site (P = .98). There were 48 repeat venoplasty procedures performed in the cephalic arch to maintain patency, including 7 repeat VIABAHN insertions. No complications were encountered.

CONCLUSIONS

The VIABAHN stent graft is a safe, effective, and durable device for treating cephalic arch stenosis when venoplasty fails.

Clinical predictors of recurrent stenosis and need for re-intervention in the cephalic arch in patients with brachiocephalic AV fistulas

INTRODUCTION

Cephalic arch stenosis is one of the most common reasons for repeated endovascular intervention and eventual abandonment of access in hemodialysis patients. There is no prediction model to identify risk factors for recurrent cephalic arch stenosis. We have developed a mathematical model to predict the need for reintervention in brachiocephalic (BC) fistulas with recurrent cephalic arch stenosis.

METHODS

Single-center retrospective analysis of 143 patients with a BC fistula referred to the vascular clinic for access dysfunction who underwent cephalic arch angioplasty were included for the analysis. Twelve-month post-index angioplasty data were analyzed using parametric, non-parametric and multiple regression models using SPSS software.

RESULTS

The mean need for re-intervention in 1 year since first index visit was 2.46 ± 1.404. Statistically significant correlation (p≤0.001) for re-intervention was observed with the severity of stenosis at index visit, access flow, vessel wall diameter proximal to the stenosis, average venous pressure >50% of the delivered blood flow rate and prolonged bleeding for >30 minutes as a reason for referral. Three equations have been derived for calculating the need for re-intervention based on the diameter of the vessel wall proximal to the stenosis.

CONCLUSIONS

Risk stratification of BC fistulas utilizing the above parameters could enable clinicians to identify accesses that are at risk for multiple re-interventions. Early identification of accesses that are at high risk for re-interventions at the cephalic arch might prolong access survival and reduce the cost for intervention by utilizing alternate strategies.

Cutting balloons, covered stents and paclitaxel-coated balloons for the treatment of dysfunctional dialysis access

Percutaneous transcatheter balloon angioplasty has evolved to the current mainstay treatment for salvage of dysfunctional dialysis access. Nonetheless, it is frequently associated with recurrent vessel restenosis and the need for multiple repeat treatments in order to maintain hemodynamic patency. Cutting-balloons, covered stents or stent-grafts, and paclitaxel-coated balloons have been extensively tested and investigated with the aim to improve immediate anatomical and long-term clinical results. Areas covered: In the present overview, we discuss the background and appraise relevant medical literature on the aforementioned technologies and provide a more in-depth synthesis of the results of different clinical studies for each device category. We will also discuss the limitations in the mode of action of each group of devices and envision what the future holds for the challenging field of dialysis access interventions. Expert commentary: We propose a good practice algorithm for the treatment of thrombosed or dysfunctional dialysis access.

Future research directions to improve fistula maturation and reduce access failure

With the increasing prevalence of end-stage renal disease, there is a growing need for hemodialysis. Arteriovenous fistulae (AVF) are the preferred type of vascular access for hemodialysis, but maturation and failure continue to present significant barriers to successful fistula use. AVF maturation integrates outward remodeling with vessel wall thickening in response to drastic hemodynamic changes in the setting of uremia, systemic inflammation, oxidative stress, and pre-existent vascular pathology. AVF can fail due to both failure to mature adequately to support hemodialysis and development of neointimal hyperplasia that narrows the AVF lumen, typically near the fistula anastomosis. Failure due to neointimal hyperplasia involves vascular cell activation and migration and extracellular matrix remodeling with complex interactions of growth factors, adhesion molecules, inflammatory mediators, and chemokines, all of which result in maladaptive remodeling. Different strategies have been proposed to prevent and treat AVF failure based on current understanding of the modes and pathology of access failure; these approaches range from appropriate patient selection and use of alternative surgical strategies for fistula creation, to the use of novel interventional techniques or drugs to treat failing fistulae. Effective treatments to prevent or treat AVF failure require a multidisciplinary approach involving nephrologists, vascular surgeons, and interventional radiologists, careful patient selection, and the use of tailored systemic or localized interventions to improve patient-specific outcomes. This review provides contemporary information on the underlying mechanisms of AVF maturation and failure and discusses the broad spectrum of options that can be tailored for specific therapy.

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.

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.

Endovascular treatment of hemodialysis arteriovenous fistulas: is immediate post-interventional blood flow a predictor of patency

PURPOSE

The purpose of this study was to investigate if the immediate hemodynamic outcome of an endovascular intervention on a dysfunctional hemodialysis arteriovenous fistula is a prognostic factor for primary patency.

METHODS

This was a prospective observational study including 61 consecutive patients with dysfunctional arteriovenous fistulas referred to our endovascular unit. Patients were treated in accordance with institutional standard protocol including immediate pre- and post-interventional blood flow measurements using an intravascular catheter system. The primary endpoint was primary patency at 12 months in patients with an immediate post-interventional blood flow above or below 600 ml/min. Primary patency was estimated using the Kaplan-Meier method with the standard error of the estimate. Multivariate Cox regression analysis was used to study the effect of blood flow and other potential predictor variables.

RESULTS

Post interventional flow did not significantly influence primary patency (p = 0.76). Primary patency was found to be affected by having a history of previous intervention(s) (p = 0.008, hazard ratio 2.9) or low fistula age (P=.038, hazard ratio 0.97 [one-month increase]). Primary patency in group 1 (previous intervention(s)) was 34% ± 13% at 12 months. In group 2 (no previous intervention), primary patency at 12 months was 62% ± 9%.

CONCLUSIONS

The results of this study do not provide scientific support for using the immediate hemodynamic outcome of an intervention as a prognostic factor for primary patency. Low fistula age and a history of previous intervention in particular were found to reduce primary patency significantly.