Dialysis Access Anatomy and Interventions: A Primer

Prosthetic brachial artery-external jugular vein arteriovenous grafts as a novel option for hemodialysis access: A case report

Following the exhaustion of all conventional hemodialysis access options in the upper extremities, a prosthetic arteriovenous loop was performed between the brachial artery (BA) and the external jugular vein (EJV) as a novel access option for hemodialysis in the present case report. During the procedure, a polytetrafluoroethylene graft was anastomosed to the BA and the EJV, and looped on the upper limb. The safety and reliability of BA-EJV access was evaluated by determining the complications, patency and intervention rates. The patient was then followed up for 20 months. The graft became thrombosed 20 months after the placement. There were no complications, such as infection, bleeding or aneurysmal lesions. Overall, the present study demonstrates that hemodialysis via BA-EJV access represents an unusual, yet effective and safe procedure, which may be conducted with acceptable complications and patency rates.

Hemodialysis Access: US for Preprocedural Mapping and Evaluation of Maturity and Access Dysfunction

Patients with kidney failure require kidney replacement therapy. While renal transplantation remains the treatment of choice for kidney failure, renal replacement therapy with hemodialysis may be required owing to the limited availability and length of time patients may wait for allografts or for patients ineligible for transplant owing to advanced age or comorbidities. The ideal hemodialysis access should provide complication-free dialysis by creating a direct connection between an artery and vein with adequate blood flow that can be reliably and easily accessed percutaneously several times a week. Surgical arteriovenous fistulas and grafts are commonly created for hemodialysis access, with newer techniques that involve the use of minimally invasive endovascular approaches. The emphasis on proactive planning for the placement, protection, and preservation of the next vascular access before the current one fails has increased the use of US for preoperative mapping and monitoring of complications for potential interventions. Preoperative US of the extremity vasculature helps assess anatomic suitability before vascular access creation, increasing the rates of successful maturation. A US mapping protocol ensures reliable measurements and clear communication of anatomic variants that may alter surgical planning. Postoperative imaging helps assess fistula maturation before cannulation for dialysis and evaluates for early and late complications associated with arteriovenous access. Clinical and US findings can suggest developing stenosis that may progress to thrombosis and loss of access function, which can be treated with percutaneous vascular interventions to preserve access patency. Vascular access steal, aneurysms and pseudoaneurysms, and fluid collections are other complications amenable to US evaluation. ©RSNA, 2023 Supplemental material is available for this article. Test Your Knowledge questions for this article are available through the Online Learning Center.

Practice of dialysis access interventional nephrology procedures in the Asia-Pacific region: Getting lay of the land

AIM

This cross-sectional survey aimed to determine the prevalence of Interventional Nephrology (IN) practice amongst nephrologists in the Asia-Pacific Region (APR), specifically related to dialysis access (DA).

METHODS

The Association of VA and intervenTionAl Renal physicians (AVATAR) Foundation from India conducted a multinational online survey amongst nephrologists from the Asia-Pacific to determine the practice of IN in the planning, creation, and management of dialysis access. The treatment modalities, manpower and equipment availability, monthly cost of treatment, specifics of dialysis access interventions, and challenges in the training and practice of IN by nephrologists were included in the survey.

RESULTS

Twenty-one countries from the APR participated in the survey. Nephrologists from 18 (85.7%) countries reported performing at least one of the basic dialysis access-related IN procedures, primarily the placement of non-tunnelled central catheters (n-TCC; 71.5%). Only 10 countries (47.6%) reported having an average of <4% of nephrologists performing any of the advanced IN access procedures, the most common being the placement of a peritoneal dialysis (PD) catheter (20%). Lack of formal training (57.14%), time (42.8%), incentive (38%), institutional support (38%), medico-legal protection (28.6%), and prohibitive cost (23.8%) were the main challenges to practice IN. The primary obstacles to implementing the IN training were a lack of funding and skilled personnel.

CONCLUSION

The practice of dialysis access-related IN in APR is inadequate, mostly due to a lack of training, backup support, and economic constraints, whereas training in access-related IN is constrained by a lack of a skilled workforce and finances.

Balloon assisted stent deployment in the cephalic arch (BASCA)

Cephalic arch stenosis causes repeated dysfunction and failure of arteriovenous access. Outcomes following balloon angioplasty alone in this location are unsatisfactory. Stent grafts have very good patency rates in this location. However, stent graft placement is technically challenging in this location due to the adverse angles and vectors of the cephalic arch. Stent graft deployment in this location is associated with a real risk of jailing the axillary vein, thereby precluding the use of that arm for future accesses and/or predisposes to venous edema. We describe a technique that was used to safely and effectively deploy a stent graft in the cephalic arch of a 65-year-old male patient.

Retrospective Analysis of 77 Hemodialysis Patients Shows No Cases of Steal Syndrome from Graft Taper Reduction

PURPOSE

To review the immediate flow response and incidence of steal syndrome after taper reduction of tapered dialysis grafts.

MATERIAL AND METHODS

This was a retrospective review of a quality assurance database of all hemodialysis access interventions performed between 2005 and 2017. It identified 77 patients who underwent a taper reduction procedure, involving angioplasty of the arterial limb of the graft and the arterial anastomosis for graft thrombosis/poor flow. A subset of patients underwent 5-, 6-, or 7-mm balloon taper reduction angioplasty coupled with intravascular direct flow measurement (n = 15 with 16 dialysis grafts). A two-tailed Wilcoxon matched-pairs signed-rank test was used to compare pre- and post-taper reduction flows. Mean duration of follow-up was 3.5 years (range, 0-12.5 years).

RESULTS

Mean access survival after taper reduction was 20.2 months (range, 0.10-94.4 months). Pre- and post-taper reduction access flows (mean Qb ± standard deviation) were 574 ± 315 ml/min and 929 ± 352 ml/min, respectively (P < .0001). The mean ratio of post- to pre-taper reduction flows was 1.6 (range, 1.1-10.2). No patients developed steal syndrome within 6 months after taper reduction.

CONCLUSIONS

Dialysis graft arterial anastomotic taper reduction did not result in the development of steal syndrome within 6 months. In the subset of patients who underwent flow measurements, taper reduction was associated with nearly a 2-fold improvement in access flow, which is a key predictor of access function.

The usefulness and feasibility of placing a clinch knot with a guidewire to achieve temporary hemostasis in arteriovenous dialysis access interventions

PURPOSE

To evaluate the usefulness and feasibility of using a reversible clinch knot with a guidewire in place rather than eliminating the access route during an arteriovenous hemodialysis access (AV access) intervention using the facing sheath technique.

MATERIAL AND METHODS

From July 2016 to June 2019, we retrospectively studied 78 sessions performed as interventional treatment for arteriovenous (AV) hemodialysis (HD) access using the "facing-sheath technique." In all sessions, all antegrade sheaths were removed while a 0.035-inch guidewire remained in place with purse-string suture and the clinch knot. Seventy-two sessions were performed in patients with thrombosed AV accesses (69 arteriovenous grafts [AVGs] and three arteriovenous fistulas [AVFs]), and six sessions were carried out to treat non-thrombosed AV accesses (four AVGs and two AVFs). We evaluated whether proper hemostasis and successful reinsertion of the sheath over the wire into the clinch knot was achieved. Clinical success was defined as achieving prompt restoration of blood flow for AV access, and the postintervention primary and secondary patency were also evaluated.

RESULT

In all 87 clinch knots created in 78 total sessions, proper hemostasis was achieved. All clinch knots that required reversal for additional procedures were successfully reopened (55 clinch knots in 50 sessions). The postintervention primary patency rates at 1, 3, and 6 months, and at 1 year were 77.8%, 68.9%, 55.6%, and 33.3%, respectively. The postintervention secondary patency rates at 1, 3, and 6 months, and also at 1 year were 93.3%, 91.1%, 86.7%, and 86.7%, respectively.

CONCLUSION

Our AV access intervention which used a clinch knot with purse-string suture while the guidewire remained in place was both useful and feasible for maintaining temporary hemostasis.

Treatment of failing arterio-venous dialysis graft by angioplasty, stent, and stent graft: Two-years analysis of patency rates and cost-effectiveness

The objective of this prospective randomized single-center study was to compare primary and secondary patency rates, number of percutaneous transluminal angioplasty (PTA) interventions and cost-effectiveness among PTA, deployment of a stent, or a stent graft in the treatment of failing arteriovenous dialysis grafts (AVG) due to restenosis in the venous anastomosis or the outflow vein. Altogether 60 patients with failing AVG and restenosis in the venous anastomosis or the outflow vein were randomly assigned to either PTA, placement of a stent (E-Luminexx^®) or stent graft (Fluency Plus^®). After the procedure, patients with stent or stent graft received dual antiplatelet therapy for the next three months. Follow-up angiography was scheduled at 3, 6, and 12 months unless requested earlier due to suspected stenosis or malfunction of the access. Subsequently, angiography was performed only if requested by the clinician. During a median follow-up of 22.4 (IQR=5.7) months patients with PTA, stent, or stent graft required 3.1±1.7, 2.5±1.7, or 1.7±2.1 (P=0.031) secondary PTA interventions. The primary patency rates were 0, 18 and 65% at 12 months and 0, 18 and 37% at 24 months in the PTA, stent, and stent graft group respectively (P<0.0001). The cost of the procedures in the first two years was €7,900±€3,300 in the PTA group, €8,500±€4,500 in the stent group, and €7,500±€6,200 in the stent graft group (P=0.45). We conclude that the treatment of failing dialysis vascular access by the deployment of a stent graft significantly improves its primary patency rates and decreases the number of secondary PTA interventions; however, the reduction in costs for maintaining AVG patency is not significant.

Long-term durability of Oakes salvage procedure to preserve Brescia-Cimino arteriovenous fistula

BACKGROUND

In 2002, Oakes et al described a novel procedure designed to salvage the distal cephalic venous outflow of a Brescia-Cimino fistula by placing a prosthetic graft between the brachial artery in the antecubital space and the cephalic vein at the wrist. In this fashion, the more proximal veins were saved for future procedures. Their approach was reported and found to be successful in the short term, but the long-term durability of the Oakes procedure has not been described. This study aimed to determine the long-term primary, primary-assisted, and secondary patency rates of the brachial to distal cephalic vein Oakes procedure.

METHODS

This is a retrospective review of a prospective database in a large, single institution. All patients who underwent the Oakes procedure from 1998 to 2012 were followed up to 2018. We reviewed the time to intervention, type of intervention, patency rates, and mortality of this patient population.

RESULTS

Over the 5-year study period, 14 patients were identified who underwent the Oakes procedure, of whom seven (50%) were female. The average age was 55.7 years (range, 38-73 years). All patients had a previously placed Brescia-Cimino that was not suitable for dialysis but was patent. The average number of days to placement of an Oakes brachial to distal cephalic graft was 396 (range, 119-1167) days. A total of 71% (10) of patients underwent an intervention to maintain the graft, of whom 50% (5) underwent an angioplasty and 50% (5) had a thrombectomy/revision procedure. The average number of days to first intervention was 367.3 (range, 21-1048) days from Oakes placement. Of this cohort, 30% (3) of patients had a second intervention, of whom one (33%) underwent an angioplasty and two (66%) had revisions. One patient had a third and a fourth intervention at 39 days and 74 days, respectively, that were both angioplasties. The overall number of days the Oakes procedure remained usable from placement was 843.6 (range, 21-3790) days or 2.3 years.

CONCLUSIONS

This study concluded that the Oakes procedure may extend the use of the distal dialysis access site by 2.3 years without increasing infection and is hence a durable solution that should be considered in patients requiring dialysis access.

Ultrasound-Guided Pharmacomechanical Thrombolysis and Angioplasty for Treatment of Acute Thrombotic Prosthetic Arteriovenous Access: 5-Year Experience with 154 Procedures in a Single Center

Pharmacomechanical thrombolysis (PMT) and percutaneous transluminal angioplasty (PTA) for the treatment of acute thrombotic prosthetic arteriovenous access (PAVA) are conventionally guided by radiography, which may cause radiation injury and requires the use of radiographic contrast media. The aim of the present study was to summarize our experience with ultrasound-guided PMT and PTA as an alternative to radiographic guidance. Between December 2012 and October 2016, 114 patients with acute thrombosis of PAVA were treated urgently with ultrasound-guided PMT and PTA to restore blood flow. The patients were followed up every 3 mo postoperatively. The 114 included patients underwent 154 episodes of ultrasound-guided PMT and PTA and were followed up for a mean of 20.7 ± 9.1 mo. The technical success rate was 91.6%, and the clinical success rate was 97.4%. Post-intervention-assisted primary patency rates at 3, 6, 12 and 24 mo were 90.8%, 78.8%, 66.3% and 50.9%, respectively. Post-intervention secondary patency rates at 3, 6, 12 and 24 months were 96.3%, 94.5%, 90.6% and 85.4%, respectively. PMT and PTA for the treatment of PAVA were performed successfully under the guidance of ultrasound with a success rate similar to that under radiographic guidance, thus avoiding radiation injury and contrast medium use, although close surveillance and timely intervention are imperative to ensure long-term patency.