Secondary Patency of Thrombosed Prosthetic Vascular Access Grafts with Aggressive Surveillance, Monitoring and Endovascular Management

A review of the current recommendations and practices for hemodialysis access monitoring and maintenance procedures

The growing number of prevalent arteriovenous (AV) accesses has been associated with an increase in the incidence of procedures being performed to maintain patency. To reduce the rate of unnecessary procedures, the 2019 Kidney Disease Outcome Quality Initiative guidelines addended the AV access surveillance recommendations, which includes clinical monitoring and assessment of dialysis adequacy alone. Abnormal clinical findings would necessitate follow-up angiography with or without confirmatory duplex ultrasound. Due to poor patency, increased surveillance schedules have been proposed to identify stenosis early and potentially prevent acute thrombotic events and AV access failure. In this review, we outlined current AV access monitoring and maintenance procedure recommendations, as described by the Centers for Medicare and Medicaid Services and 2019 Kidney Disease Outcome Quality Initiative guidelines. In addition, we highlight the findings of recently published randomized controlled trials that have examined increased surveillance schedules.

Failure Analysis of TEVG’s II: Late Failure and Entering the Regeneration Pathway

Tissue-engineered vascular grafts (TEVGs) are a promising alternative to treat vascular disease under complex hemodynamic conditions. However, despite efforts from the tissue engineering and regenerative medicine fields, the interactions between the material and the biological and hemodynamic environment are still to be understood, and optimization of the rational design of vascular grafts is an open challenge. This is of special importance as TEVGs not only have to overcome the surgical requirements upon implantation, they also need to withhold the inflammatory response and sustain remodeling of the tissue. This work aims to analyze and evaluate the bio-molecular interactions and hemodynamic phenomena between blood components, cells and materials that have been reported to be related to the failure of the TEVGs during the regeneration process once the initial stages of preimplantation have been resolved, in order to tailor and refine the needed criteria for the optimal design of TEVGs.

Brachio-basilic upper arm transposition fistulas vs. prosthetic brachio-axillary vascular access grafts-Which one is preferred for hemodialysis?

INTRODUCTION

There is still controversy on the use of brachio-basilic upper arm transposition fistula (BBAVF) and prosthetic brachio-axillary vascular access grafts (BAPTFE) in patients with no suitable cephalic veins for creating an autogenous brachio-cephalic fistula.

METHODS

In a randomized controlled clinical trial, 60 hemodialysis patients who were not a suitable candidate for BCAVF were randomly assigned into two groups: BBAVF and BAPTFE. The patients were clinically followed up to 1 year and the patency rate and access-related complications were compared between the two groups.

FINDINGS

Access failure rate in the BBAVF and BAPTFE groups was 30.0% and 36.6%, respectively. The primary patency time was 232.73 ± 113.36 and 261.53 ± 147.37 days, respectively (P = 0.40). Thrombosis formation and infection were the two main causes for access failure, yet indicating no significant difference between the two groups (P > 0.05).

DISCUSSION

BBAVF and BAPTFE have comparable clinical outcomes in short-term follow-up. Therefore, BAPTFE can be used as an alternative vascular access for hemodialysis in patients who are not a suitable candidate for BBAVF.

Hybrid salvage of thrombosed dialysis access grafts

BACKGROUND

To report our experience and evaluate the results of a hybrid procedure comprising of surgical thrombectomy and adjuvant high pressure balloon angioplasty for management of thrombosed arteriovenous grafts (AVGs) with underlying venous anastomotic stenosis.

METHODS

Between January 2015 and June 2017, 148 patients with first-time thrombosis of AVGs were considered for treatment with surgical thrombectomy followed by high pressure balloon angioplasty of the underlying venous anastomotic lesions. Monitoring and surveillance was subsequently performed using clinical and hemodialysis criteria to detect a failing/failed access. Primary, assisted primary, and secondary patency rates were calculated using Kaplan-Meier analysis.

RESULTS

This hybrid procedure was technically successful in 135 cases (91.2%) and clinically successful in 131 cases (88.5%). The postintervention primary patency rate of the target lesions was 68.2%, 52.4%, and 44.2% at 3, 6, and 12 months, respectively. Endovascular re-interventions increased significantly the postintervention assisted primary patency to 79.1%, 71.9%, and 66.8% (P=0.0004), and the postintervention secondary patency to 86.5%, 82.2%, and 78.6% (P<0.0001) at the same time points, respectively.

CONCLUSIONS

Hybrid salvage of thrombosed AVGs using high pressure balloon angioplasty of the venous anastomotic stenosis following surgical thrombectomy by Fogarty catheter is a highly successful and safe procedure, with acceptable short-term primary patency. The need for repeated interventions demonstrates the necessity of continuous graft monitoring and surveillance to improve both assisted primary, and secondary patency rates.

Prosthetic Arteriovenous Grafts for Hemodialysis

Introduction

Prosthetic arteriovenous (AV) grafts are indicated in patients with failed AV fistula (AVF), exhausted superficial veins or unsuitable vessels. Increasing the proportion of prevalent hemodialysis (HD) patients using autogenous AVF should reduce the need for AV grafts and associated morbidity. This paper reviews the current role of prosthetic AV grafts in vascular access for HD.

Technical considerations

Prior to the insertion of a prosthetic AV graft, a comprehensive review of previous access procedures and full physical examination in addition to vessel mapping is required. Anastomotic technique should take into account the flow diffuser concept, graft geometry and an anastomotic angle of 15° in order to reduce the incidence of intimal hyperplasia.

Results

Many authors report 1 and 2-yr cumulative graft patency rates of 59–90% and 50–82%, respectively. The major drawbacks with synthetic grafts include: thrombosis, a five-fold increase in infection risk and steal syndrome. The choice between surgical and percutaneous methods of dealing with blocked AV grafts remains controversial, though percutaneous techniques are assuming an increasingly important role. Percutaneous strategies are successful in declotting access in 67–95% of cases. Stenting of stenotic lesions following thrombectomy improves secondary patency rates. Strategies for dealing with AV graft infection include antibiotic prophylaxis, partial, subtotal or total graft excision and the use of biological prosthesis.

Conclusions

Though more prone to complications than autogenous AVFs, AV grafts offer a short maturation period and are more amenable to thrombectomy by radiological or surgical means. Complex AV grafts may be appropriate in patients with exhausted access sites.

Arteriovenous Access Failure, Stenosis, and Thrombosis

Vascular access–related complications can lead to patient morbidity and reduced patient quality of life. Some of the common arteriovenous access complications include failure to mature, stenosis formation, and thrombosis.

Review of Transposed Basilic Vein Access for Hemodialysis

Background

There is ongoing debate about the use of transposed basilic vein (TBV) fistula and the choice between it and prosthetic arteriovenous graft (AVG). This paper reviews the available literature relating to TBV fistula in terms of surgical technique, patency rates, complications, access survival and compares it with prosthetic AVG for hemodialysis (HD).

Methods

Review of English language publications on TBV during the last two decades.

Findings

The rate of fistula maturation was higher in the two-stage group, although the mean diameter of the basilic vein was smaller. Dialysis via central venous catheters at time of surgery was most prevalent in patients undergoing staged procedures—14% in one-stage TBV and 43% in two-stage TBV. Several authors report 1-year cumulative patency rate of 47% to 96% and 59% to 90% for TBV and AVG, respectively. TBV provides a more cost-effective option and should be considered the next choice when primary autogenous fistulae are not possible, whereas AVGs are easier to create, can be punctured earlier and have a greater reintervention rate if the access fails.

Conclusions

This analysis shows that TBV has several advantages over AVG and provides a valuable access for HD but raises the need for a comparative trial between TBV and the newer generation AVGs. There is no clear superiority of the one-stage over the two-stage procedure.

Outcomes of percutaneous interventions in transposed hemodialysis fistulas compared with nontransposed fistulas and grafts

PURPOSE

To compare postpercutaneous intervention outcomes of autogenous venous-transposition arteriovenous fistulas (AVFs) versus those of autogenous nontransposed AVFs (nAVFs) and prosthetic arteriovenous grafts (AVGs).

MATERIALS AND METHODS

A total of 591 hemodialysis accesses (195 transposed AVFs [tAVFs], 205 nAVFs, 191 AVGs) in 522 patients (278 male; mean age, 57 y; range, 15–91 y) underwent percutaneous transluminal angioplasty (PTA) and/or mechanical thrombectomy (ie, declotting). Access characteristics, surgical history, percutaneous interventions, postinterventional primary and secondary access patency, and follow-up data were collected. Cox proportional-hazards regression analyses, Fisher exact tests, and χ2 tests were performed.

RESULTS

Mean follow-up period was 32 months. Mean access ages at initial percutaneous intervention were 260 days (tAVF), 206 days (nAVF), and 176 days (AVG; P < .01). One-year postinterventional primary patency (PIPP) rates were 25% (tAVF), 24% (nAVF), and 14% (AVG). One-year postinterventional secondary patency (PISP) rates were 77% (tAVF), 61% (nAVF), and 63% (AVG). Median PIPP durations were 138 days (tAVF), 121 days (nAVF), and 79 days (AVG; P = .0001). Median PISP durations were 1,076 days (tAVF), 783 days (nAVF), and 750 days (AVG; P = .019). Total interventions needed to maintain PISP were 2.4 (tAVF), 1.3 (nAVF), and 3.2 (AVG) per patient-year (P < .001), which included 1.9, 1.2, and 1.4 PTAs (P < .01) and 0.45, 0.15, and 1.8 declotting procedures, respectively (P < .001).

CONCLUSIONS

Based on the number of percutaneous interventions needed to maintain PISP, these results confirm the current Dialysis Outcomes Quality Initiative access preference of nAVFs before tAVFs before AVGs. tAVFs offered superior postinterventional outcomes than AVGs. With additional interventions, tAVFs could even outperform nAVFs in terms of PISP.

Hybrid Simultaneous Treatment of Thrombosed Prosthetic Grafts for Hemodialysis

Purpose

The aim of the study was to evaluate our experience in the hybrid simultaneous treatment (open and endovascular) of acute thrombosis of prosthetic grafts for hemodialysis.

Methods

Between January 2011 and June 2013, 23 patients with acute thrombosis of a prosthetic graft for hemodialysis were urgently treated with a hybrid simultaneous treatment in order to obtain a prompt restoration of the flow. A new puncture of the graft was scheduled after 24 hours.

Results

Intraoperative technical success was 100% with a completion angiography showing the restored patency of the graft. As adjunctive procedures, in 6 patients (26.1%) locoregional thrombolysis was necessary and in all cases further endovascular manoeuvres (angioplasty/stenting) were immediately performed to solve a significant stenosis of the venous anastomosis/first tract of the vein. At 24 hours when the first puncture was done, three grafts were occluded resulting in a primary patency of 87%. During the follow-up (mean duration 5.6 months) four reocclusions occurred. In-stent restenosis occurred in all patients undergone stenting. At 1 year the rates of primary patency, primary assisted patency and secondary patency were 58.7%, 78.3% and 87%, respectively.

Conclusions

In our series the combined simultaneous hybrid approach in urgency maximizes the use of different available techniques, which appeared to improve overall success rate to save a thrombosed graft for hemodialysis. The great difference showed between primary and primary assisted patency demonstrates the necessity of a close follow-up.

Allogenous vein graft as vascular access for hemodialysis--lost battle?

PURPOSE

The purpose of this paper is to assess a long-term outcome of allogenous vein grafts (ALVG) as vascular access for hemodialysis.

MATERIALS AND METHODS

For nearly eight years (between 9/2002 and 9/2011) a total of 78 patients with 112 ALVGs were involved in the study. The register included 46 women and 32 men, mean age 66.1 ± 11.2 years; range 20-88 years. The patient database was retrospectively reviewed and statistical processing was performed.

RESULTS

Almost all ALVGs were treated by PTA or surgically, very often repeatedly. The number of radiologic interventions was 316, the number of surgical procedures 31. Mean follow-up time was 795 days, range 28-3522 days. Thirty-five patients died of unrelated causes, nineteen with functional graft, fourteen patients were lost to follow-up. Forty ALVGs failed for various reasons, mostly because of occlusion. Only one patient underwent successful renal transplantation, no patient converted to peritoneal dialysis. Thirty-seven ALVGs remain correctly functioning. Primary patency rates at 6, 12, and 24 months were 81 ± 5%, 63 ± 5%, and 34 ± 2% respectively. Secondary patency rates at 6, 12, and 24 months were 96 ± 2%, 82 ± 4%, and 65 ± 5% respectively.

CONCLUSIONS

Allogenous vein grafts, in spite of the high number of necessary radiologic and surgical interventions and reinterventions, show acceptable clinical usability and durability, comparable with other types of prosthetic grafts.

Long-term complication and patency rates of Vectra and IMPRA Carboflo Vascular Access Grafts with aggressive monitoring, surveillance and endovascular management

The purpose of this study is to compare infection, pseudoaneurysm formation and patency rates during long-term follow-up of polyurethane and polytetrafluoroethylene (PTFE) vascular access grafts maintained with contemporary endovascular methods. During a 34-month period, 239 polyurethane and 125 carbon-impregnated PTFE vascular access grafts were placed in 324 consecutive patients. Thirty-six patients (9.9%) developed a pseudoaneurysm (anastomotic, n = 6 or at the needle-stick site, n = 30). An additional 19 patients (5.2%) required graft excision for infection. Three-year graft infection and pseudoaneurysm formation (at needle-stick site) rates were similar in polyurethane and PTFE grafts (11% versus 8%, P = 0.61, and 17% versus 23%, P = 0.72, respectively). Three-year secondary patency was better in polyurethane than PTFE grafts (69% versus 57%, respectively, P = 0.012). Straight upper arm polyurethane grafts had the best secondary patency ( P = 0.001). Contemporary long-term secondary patency of vascular access grafts is satisfactory. Further follow-up is necessary to compare late infection and pseudoaneurysm formation rates.

Comparison of Clinical Effectiveness between Surgical and Endovascular Treatment for Thrombotic Obstruction in Hemodialysis Access

Purpose

Endovascular treatment (ET) is widely used for thrombotic complications of vascular access (VA) for hemodialysis. We evaluated the effectiveness of both ET and surgical interventions for thrombotic complications.

Methods

We studied 533 patients who underwent surgical procedures (a total of 879 procedures) and 54 patients who received ET (a total of 156 procedures) for VA obstruction (endovascular group; group 1). The 533 patients who underwent surgical procedures were further divided into two groups: the surgical balloon-angioplasty group (the thrombus was surgically removed and the stenotic lesions were dilated by balloon angioplasty; 189 procedures; group 2) and the surgical repair group (the stenotic lesions were bypassed with additional graft diversion or creation of a new access; 690 procedures; group 3). The three groups were evaluated for VA patency.

Results

Using the Kaplan-Meier method, the 2–yr patency for groups 1, 2, and 3 were 11.1%, 11.5%, and 34.0% (p<0.0001). The 2–yr patency rates in patients in whom arteriovenous grafts were used were 5.9% (group 1), 9.2% (group 2), and 22.8% (group 3) (p<0.0001), whereas in patients with arteriovenous fisutulae they were 33.7% (group 1), 35.7% (group 2), and 59.8% (group 3) (p=0.0005).

Conclusions

A surgical approach may cause difficulty in creating a new VA, because useful access vessels are limited. Our results indicate surgical balloon-angioplasty and ET provide the same patency. ET is less invasive and can be repeated, which makes it beneficial for the patients. We concluded ET could be considered as the first-line treatment for thrombotic complications.

Surgical or endovascular repair of thrombosed dialysis vascular access: is there any evidence?

INTRODUCTION

Endovascular and surgical strategies have been used to manage patients with thrombosed vascular access for hemodialysis. We analyzed the evidence to see whether endovascular or surgical treatment has the best outcome in terms of primary success rate and long-term patency.

METHODS

We performed a systematic literature search of endovascular and surgical repair of thrombosed hemodialysis vascular access. The analysis included meta-analysis, randomized, and population-based studies of thrombosed arteriovenous fistulae and grafts.

RESULTS

One meta-analysis and eight randomized studies on the treatment of arteriovenous graft thrombosis were identified. Studies conducted before 2002 demonstrated a significantly better primary success rate and primary and secondary patencies of surgical thrombectomy vs endovascular intervention. After 2002, similar results of both techniques have been reported. Only population-based studies on the treatment of thrombosed autogenous arteriovenous fistulae have been published, showing similar outcome of surgical and endovascular intervention in terms of primary success. The long-term primary and secondary patencies are slightly better for surgical treatment, but this concerns only forearm fistulae.

CONCLUSIONS

The outcome of endovascular and surgical intervention for thrombosed vascular access is comparable, in particular for thrombosed prosthetic grafts. Surgical treatment of autogenous arteriovenous fistulae is likely to have benefit compared with endovascular means. Definitive randomized trials are needed to provide the level 1 evidence to resolve this latter issue.