Comparison of outcomes of arteriovenous grafts and fistulas at a single Veterans' Affairs medical center

Impact of arteriovenous fistulas versus arteriovenous grafts on vascular access performance in haemodialysis patients: A systematic review and meta-analysis

BACKGROUND

Controversy exists regarding the best-performing vascular access type for patients undergoing haemodialysis. We aimed to compare outcomes of starting dialysis on arteriovenous fistulas (AVFs) versus arteriovenous grafts (AVGs) in haemodialysis patients.

METHODS

We conducted a systematic search of multiple electronic information sources and bibliographic reference lists. The following outcome parameters were evaluated at 1, 2 and 5 years: primary failure, defined as access never used for dialysis; primary patency, defined as intervention-free access survival; primary-assisted patency, defined as uninterrupted access survival with interventions; and secondary patency, defined as cumulative access survival.

RESULTS

We identified 15 comparative studies reporting a total of 118,434 patients who initiated haemodialysis with AVF (n = 95,143) or AVG (n = 23,291). Our analysis demonstrated that AVF was associated with significantly higher primary failure rate (OR: 2.05, p = .0005) but significantly higher rate of primary patency at 1 year (OR: 1.91, p < .00001), at 2 years (OR: 2.52, p < .00001) and at 5 years (OR: 2.59, p < .00001); and primary-assisted patency at 1 year (OR: 1.71, p < .00001), at 2 years (OR: 2.13, p < .00001) and 5 years (OR: 2.79, p < .00001). There was no significant difference in secondary patency at 1 year (OR: 1.08, p < .00001) but AVF had better secondary patency at 2 years (OR: 1.26, p < .00001) and 5 years (OR: 1.60, p < .00001) than AVG.

CONCLUSIONS

The meta-analysis of best available comparative evidence (Level 2) demonstrated that AVFs may be associated with significantly higher primary failure rate but higher primary patency, primary-assisted patency and secondary patency at 1, 2 and 5 years compared to AVGs. However, the available evidence is subject to significant selection bias and confounding by indication.

Salvage of Suboptimal or Occluded Arteriovenous Fistulas Using a 4 French System From the Radial Artery for Initial Balloon Angioplasty Maturations

Introduction End-stage renal disease (ESRD) is a condition that has seen a large increase in prevalence in recent decades. Paralleling this increase in prevalence is the increasing number of patients requiring vascular access for hemodialysis. Arteriovenous fistulas (AVFs) and arteriovenous grafts (AVGs) are considered the procedures of choice for hemodialysis access. However, due to the suboptimal venous anatomy (<2 mm diameter, sclerotic vascular walls) and chronic medical conditions (diabetes mellitus) seen in many ESRD patients, successful AVF creation and maturation is not always possible using standard procedures. In this study, we performed primary balloon angioplasty (PBA) at the time of AVF creation with subsequent balloon angioplasty maturation (BAM) procedures in a group of patients with a large proportion of diabetes and suboptimal venous anatomy. The purpose of this study was to compare the assisted patency and survival rates in patients with suboptimal veins used to create AVFs to patients with standard vein AVFs and AVGs.  Methods Over a nine-year period, PBA during AVF creation was performed 682 times. Of these, 551 AVFs were matured in optimally sized veins using standard BAM procedures, and 131 AVFs were matured in suboptimal veins utilizing a modified approach. In the subset of patients with suboptimal venous anatomy, we performed the initial BAM procedure via the radial artery utilizing a 4 French system. Additionally, routine clinical surveillance was scheduled throughout the study period for all patients. Suboptimal veins included small (<2 mm diameter), sclerotic, accessory, or recanalized veins. During the study period, 69 AVGs were created and matured using standard graft-gram procedures. A Kaplan-Meier analysis of survival and assisted patency rates comparing the three groups were calculated utilizing data from a retrospective database and medical records. A hazard ratio and a log-rank test were calculated to assess statistical significance. Results The mean time of follow-up for all three groups (n=703) was 43.2 months. Among patients requiring hemodialysis access in the study, the fistula creation rate was 90.8%. Patients with suitable venous anatomy who underwent AVF creation with PBA and standard BAM procedures experienced higher primary assisted patency rates relative to the suboptimal vein AVF and AVG groups (p<0.0001). No difference was seen between the suboptimal vein AVF and AVG groups. Patient survival and the percentage of diabetics were comparable amongst all three groups. Conclusion Using our approach, we were able to achieve a high AVF creation rate amongst a group of patients with a large proportion of suboptimal veins and diabetes. Despite not performing as well as standard vein AVFs in regards to primary assisted patency, the patients with suboptimal vein AVFs experienced similar patency and survival rates as compared to patients receiving AVGs. This new approach enhances the ability to create AVFs in patients who would otherwise not be amenable to fistulas and may contribute to reduced complication risk and improved overall survival.

The Effect of Risk of Maturation Failure and Access Type on Arteriovenous Access-Related Costs among Hemodialysis Patients

BACKGROUND

Several studies report lower costs associated with attaining and maintaining patency for arteriovenous (AV) fistulas as compared to AV grafts among patients receiving hemodialysis. However, these costs may vary according to the AV access's risk of failure to mature (FTM). The aim of this study was to examine the effect of AV access type and risk of FTM on the total costs of attaining and maintaining AV access patency over 1, 3, and 5 years postcreation, among incident accesses.

METHODS

All first AV access creations (January 1, 2002-January 1, 2018), revisions/resections, and interventions from a single academic institution were prospectively captured. The units costs (from 2011 in CA$) were estimated primarily through the provincial patient Ontario Case Costing Initiative database. The present value of total vascular access-related costs from a third-party payer perspective was calculated by multiplying specific unit costs by the number of AV access creations, revisions/resections, and interventions from the date of creation to 1, 3, and 5 years post creation. The potential associations of AV access type and FTM risk stratum with AV access cost were examined using log-linear models and generalized estimating equations.

RESULTS

A total of 906 patients were included in the study, of which 696 had fistulas and 210 had grafts. The median present value of total costs to attain and maintain AV access over 1, 3, and 5 years was positively associated with the highest FTM risk stratum in all models. It was not associated with AV access type when the interaction between AV access type and FTM risk stratum was considered.

CONCLUSIONS

The costs of attaining and maintaining AV access were increased among patients with high/very high FTM risk. Risk of FTM, related interventions, and costs should be considered when choosing vascular access type for an individual patient.

KDOQI Clinical Practice Guideline for Vascular Access: 2019 Update

The National Kidney Foundation's Kidney Disease Outcomes Quality Initiative (KDOQI) has provided evidence-based guidelines for hemodialysis vascular access since 1996. Since the last update in 2006, there has been a great accumulation of new evidence and sophistication in the guidelines process. The 2019 update to the KDOQI Clinical Practice Guideline for Vascular Access is a comprehensive document intended to assist multidisciplinary practitioners care for chronic kidney disease patients and their vascular access. New topics include the end-stage kidney disease "Life-Plan" and related concepts, guidance on vascular access choice, new targets for arteriovenous access (fistulas and grafts) and central venous catheters, management of specific complications, and renewed approaches to some older topics. Appraisal of the quality of the evidence was independently conducted by using a Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach, and interpretation and application followed the GRADE Evidence to Decision frameworks. As applicable, each guideline statement is accompanied by rationale/background information, a detailed justification, monitoring and evaluation guidance, implementation considerations, special discussions, and recommendations for future research.

Patient-Centric Analysis of Dialysis Access Outcomes

Objective

Dialysis access literature has traditionally focused on fistula patency as the primary outcome measure, but this approach falls short in describing the entire spectrum of dialysis access care. Using our prospectively maintained vascular access data base, a comprehensive, patient-centered analysis of arteriovenous access placement and interventions, central venous catheter use, and associated complications is performed.

Methods

Twenty-six patients receiving 39 arteriovenous fistula (AVF), eight prosthetic grafts and 52 catheters were followed longitudinally for an average of 4.1 yrs to determine the time of initial cannulation, need for revision, and the time of abandonment for each AV access. Access complications secondary to infection, thrombosis, stenosis, and aneurysmal degeneration were tabulated. The time of permanent dialysis catheter placement and removal was collected, along with infection and thrombotic complications related to their use.

Results

Fifty-four percent of the AVFs matured without the need for intervention, while 13% required revision to promote maturation. One-third of the AVFs failed primarily or following revision and were never used for dialysis. Fistulae were initially cannulated an average of 9.5 months following implantation and lasted 27.2 months before abandonment. AVF revisions were performed an average of 7.5 months following maturation and provided an additional 19.8 months of usability. Fifty percent of prosthetic grafts could be used without intervention, while 25% were used only after revision and 25% were abandoned without being used. Grafts were accessed an average of 2.7 months after implantation and lasted 14.1 months after the initial cannulation. Twenty-three patients received a total of 52 catheters during the study, with an average implantation time of 6.5 months. Sixty-three percent of the catheters developed one or more complications, for a rate of 1.3 complications per year of indwelling catheter.

Conclusion

The current study provides a novel approach for the comprehensive evaluation of access care for patients undergoing hemodialysis through the development of a patient-centric approach to examine the complexities and shortcomings in dialysis access care. Despite some difficulties in achieving fistula maturation, an AVF prevalence rate was 66%, meeting the 65% goal set by the Fistula First Initiative. Unfortunately, a significant portion of the remainder of the dialysis support was provided by catheters, with a 27% catheter prevalence rate.

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.

The influence of metabolic syndrome on hemodialysis access patency

OBJECTIVE

The natural history of patients with metabolic syndrome (MetS) undergoing hemodialysis access placement is unknown. MetS has previously been found as a risk factor for poor outcomes for vascular surgery patients undergoing other interventions. The aim of this is study is to describe the outcomes of MetS patients undergoing primary hemodialysis access placement.

METHODS

The medical records of the 187 patients who underwent hemodialysis access placement between 1999 and 2009 at the Veterans Administration Connecticut Healthcare System were reviewed. Survival, primary patency, and secondary patency were evaluated using the Gehan-Breslow test for survival. MetS was defined as the presence of three or more of the following: blood pressure≥130/90 mm Hg; triglycerides≥150 mg/dL; high-density lipoprotein≤50 mg/dL for women and ≤40 mg/dL for men; body mass index≥30 kg/m2; or fasting blood glucose≥110 mg/dL.

RESULTS

Of the 187 patients who underwent hemodialysis access placement, 115 (61%) were identified to have MetS. The distribution of MetS factors among all patients was hypertension in 98%, diabetes in 58%, elevated triclyceride in 39%, decreased high-density lipoprotein in 60%, elevated body mass index in 36%, and 39% were currently receiving hemodialysis. Patients were a mean age of 66 years. The median length of follow-up was 4.2 years. The forearm was site of fistula placement in 53%; no difference existed between groups (MetS, 57%; no MetS, 50%; P=.388). The median time to primary failure was 0.46 years for all patients (MetS, 0.555 years; no MetS, 0.436 years; P=.255). Secondary patency was 50% at 1.18 years for all patients (no MetS, 1.94 years; MetS, 0.72 years; P=.024). Median survival duration for all patients was 4.15 years (no MetS, 5.07 years; MetS, 3.63 years; P=.019).

CONCLUSIONS

MetS is prevalent among patients undergoing hemodialysis access placement. Patients with MetS have equivalent primary patency rates; however, their survival and cumulative patency rates are significantly lower than in patients without MetS. Patients with MetS form a high-risk group that needs intensive surveillance protocols.

Clinical analysis of hemodialysis vascular access: comparision of autogenous arterioveonus fistula & arteriovenous prosthetic graft

BACKGROUND

Mature autogenous arteriovenous fistulas have better long term patency and require fewer secondary interventions compared to arteriovenous prosthetic graft. Our Study evaluated vascular patency rates and incidence of interventions in autogenous arteriovenous fistulas and grafts.

MATERIAL AND METHODS

A total of 166 vascular access operations were performed in 153 patients between December 2002 and November 2009. Thirty seven caeses were excluded due to primary access failure and loss of follow-up. One group of 92 autogenous arterioveous fistulas and the other group of 37 arteriovenous prosthetic grafts were evaluated retrospectively. Primary and secondary patency rates were estimated using the Kaplan-Meier method.

RESULTS

The primary patency rate (84%, 67%, 51% vs. 51%, 22%, 9% at 1, 3, 5 year; p=0.0000) and secondary patency rate (96%, 88%, 68% vs. 88%, 65%, 16% at 1. 3, 5 year; p=0.0009) were better in autogenous fistula group than prosthetic graft group. Interventions to maintain secondary patency were required in 23% of the autogenous fistula group (average 0.06 procedures/patient/year) and 65% of prosthetic graft group (average 0.21 procedures/patient/year). So the autogenous fistula group had fewer intervention rate than prosthetic graft group (p=0.01) The risk factor of primary patency was diabetus combined with ischemic heart disease and the secondary patency's risk factor was age.

CONCLUSION

Autogenous arteriovenous fistulas showed better performance compared to prosthetic grafts in terms of primary & secondary patency and incidence of interventions.

Comparison among Transposed Brachiobasilic, Brachiobrachial Arteriovenous Fistulas and Flixene™ Vascular Graft

Objective

To compare the outcomes of 3 upper arm access types: transposed brachiobasilic arteriovenous fistula (BBAVF), autogenous brachial vein–brachial artery access (ABBA), and a new type of ePTFE graft (Flixene™ graft) (AVG), in a consecutive series of patients treated in a tertiary centre.

Methods

A prospective, computerized access database was analysed retrospectively to identify all patients undergoing BBAVF, ABBA, or AVG between January 1, 2008, and December 31, 2009.

Results

A total of 108 patients were identified; of whom 45 had BBAVF, 15 ABBA, and 48 ePTFE brachioaxillary AVG. Early failure was similar in all 3 groups. The 18–month functional patency rates for the ABBAs, BBAVFs, and grafts were 27%, 51%, and 55%, respectively. The median time to first use for AVGs was significantly shorter (p<0.0001). Complications were not more frequent in AVGs than ABBAs and BBAVFs (p=0.127). The total number of access interventions was similar between the AVG and ABBA groups (p=0.58), but it was significantly higher in the AVG group compared with the BBAVF group (p<0.0001).

Conclusions

This study supports the current recommendations of the NKF Kidney Disease Outcomes Quality Initiative for using BBAVFs as third choice after radiocephalic and brachiocephalic arteriovenous fistulas. We also showed good results with a new type of prosthetic graft (Flixene™ graft) that allows cannulation within days of implantation. We now favour the use of this graft instead of basilic vein transposition in elderly patients with short life expectancy and urgent need of renal access.

Thigh grafts contribute significantly to patients' time on dialysis

BACKGROUND AND OBJECTIVES

Thigh grafts are placed in hemodialysis patients who have exhausted all arm access sites. The goal of this study was to compare the survival, complication rates, and overall contribution of thigh grafts with arm grafts and fistulas in patients with at least one functional thigh graft during their dialysis history.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This longitudinal review of a prospectively acquired clinical database included 85 thigh graft recipients. The rates of survival, thrombosis, infection, and other complications were determined for a total of 268 fistulas, arm grafts, and thigh grafts placed in these patients.

RESULTS

In this patient subset, thigh graft primary failure rate was lower than arm grafts and fistulas (3 versus 13 and 61%, respectively). Excluding primary failures, thigh grafts survived longer than both arm grafts and mature fistulas (53 versus 14 and 32%, at 3 years; 47 versus 3 and 11% at 5 years). Thigh grafts had a lower thrombosis rate than arm grafts (0.543 versus 1.457/patient-year) but similar rates of loss as a result of infection and surgical revision. In patients with previous arm accesses, thigh grafts contributed 51% of total dialysis time compared with 38 and 11% for arm grafts and fistulas.

CONCLUSIONS

Thigh grafts provide long-term, thrombosis- and infection-free dialysis access for patients with exhausted arm access sites. The decision for thigh graft placement should, therefore, be made as soon as there is evidence for unavailability of arm access sites so that catheter use can be minimized.

Preoperative mapping for haemodialysis access surgery with CO(2) venography of the upper limb

OBJECTIVE

This study aims to evaluate the impact of CO(2) venography on the planning and outcome of native arteriovenous fistula (AVF) creation.

METHODS

Records of patients who underwent CO(2) venography prior to access surgery between January 2000 and December 2008 were reviewed. CO(2) venography was performed selectively in chronic kidney disease (CKD) in stage IV-V patients without suitable veins on clinical examination. Findings at surgery were compared to CO(2) venography images. Patency of AVFs was analysed by the Kaplan-Meier method. Differences in outcome of maturation were compared using a chi(2) test.

RESULTS

A total of 209 CO(2) venograms were obtained in 116 patients. In 89 patients (77%), 101 AVFs (21 forearm AVF (21%) and 80 elbow AVF (79%) were created. Surgical findings corresponded with CO(2) venography findings in 90% of patients. In 10 cases (10%), access was created at the elbow despite a patent forearm cephalic vein on CO(2) venography (n = 2) or access was attempted with a vein which was thought to be unsuitable on CO(2) venography (n = 8). Maturation rate of the latter was 50% (4/8) vs. 88% (80/91) for AVFs created with veins considered usable (P = 0.004). The overall maturation rate was 84% with 1-year primary, assisted primary and secondary patency rates of 63%, 70% and 71%, respectively.

CONCLUSION

CO(2) venography is a useful tool for venous mapping prior to vascular access surgery, resulting in an overall maturation rate of 84% and good patency rates.