AV Fistula Rates: Changing the Culture of Vascular Access

Risk of infections related to endovascular catheters and cardiac implantable devices in hemodialysis patients

Patients requiring dialysis are extremely vulnerable to infectious diseases. The high burden of comorbidities and weakened immune system due to uremia and previous immunosuppressive therapy expose the patient on dialysis to more infectious events than the general population. The infectious risk is further increased by the presence of endovascular catheters and implantable cardiologic devices. The former is generally placed as urgent vascular access for dialysis and in subjects requiring hemodialysis treatments without autogenous arteriovenous fistula. The high frequency of cardiovascular events also increases the likelihood of implanting indwelling implantable cardiac devices (CIED) such as pacemakers (PMs) and defibrillators (ICDs). The simultaneous presence of CVC and CIED yields an increased risk of developing severe prosthetic device-associated bloodstream infections often progressing to septicemia. Although, antibiotic therapy is the mainstay of prosthetic device-related infections, antibiotic resistance of biofilm-residing bacteria reduces the choice of infection eradication. In these cases, the resolution of the infection process relies on the removal of the prosthetic device. Compared to CVC removal, the extraction of leads is a more complex procedure and poses an increased risk of vessel tearing. As a result, the prevention of prosthetic device-related infection is of utmost importance in hemodialysis (HD) patients and relies principally on avoiding CVC as vascular access for HD and placement of a new class of wireless implantable medical devices. When the combination of CVC and CIED is inevitable, prevention of infection, mainly due translocation of skin bacteria, should be a mandatory priority for healthcare workers.

Maintenance and Salvage of Hemodialysis Access

Many end-stage kidney failure patients require hemodialysis as a life-sustaining treatment. Hemodialysis access via arteriovenous fistula or graft creation is preferred over long-term dialysis catheters, but intervention to maintain patency and prevent access failure is common. Endovascular and open surgical techniques are both utilized to address the underlying etiology of failure. Endovascular options include balloon angioplasty, angioplasty with stenting, and drug-eluting stents. Open revision is commonly needed for recurrent stenosis, aneurysmal or pseudoaneurysmal change, hemodialysis access-induced distal ischemia, and infection. Treatment plans should be guided by patient's individualized goals of care and require a multidisciplinary approach to the management of this complex disease.

Real-World Usage of the WavelinQ EndoAVF System

BACKGROUND

Dependent on existing deep to superficial perforating venous branches, the WavelinQ EndoAVF System is a novel technique used to create an arteriovenous fistula (AVF) between ulnar or radial veins and concomitant arteries for dialysis access. We sought to examine a single center's success rates and short-term follow-up using this device.

METHODS

All consecutive patients undergoing placement of a WavelinQ AVF from October 2018 to July 2019 were included. Preoperative/intraoperative variables including demographics, preoperative/postoperative duplex ultrasonography, success rate of procedure, and subsequent endovascular/surgical procedures were obtained. Descriptive statistics and comparison of groups requiring subsequent intervention were performed.

RESULTS

Thirty-five patients underwent placement of the WavelinQ AVF, with 32 (91%) patients having at least one documented follow-up. These patients were predominantly male (23/32, 72%) with an average age of 60.2 and 23 of 32 (72%) patients were on dialysis. Initial fistula creation success rate was 100%. Average procedural length was 120 min, fluoroscopy time 9.6 min, and contrast usage 52.2 mL. Eight of 32 (25%) patients had perioperative complications (3 hematomas, 3 contrast extravasations, 1 resolved vessel spasm all resolving spontaneously, and 1 pseudoaneurysm requiring surgical repair). Thirteen of 32 (41%) patients underwent subsequent endovascular interventions to assist with maturation [9/32 (28%) branch coiling, 5/32 (16%) angioplasty/stenting, and 3/32 (9%) access thrombectomy] and 4 of 32 (13%) patients required subsequent surgical interventions (1 pseudoaneurysm repair, 1 revision of fistula, and 2 definitive AVF creation in thrombosed grafts). The majority of accesses (30/32, 94%) were ulnar-ulnar fistulas and overall patency at average follow-up of 73 days was 88% (28/32) with average brachial artery inflow volume of 1,078 cc/min and average cephalic vein (18/32) outflow volume of 447 cc/min. Eleven of 23 (48%) patients on dialysis were successfully using the EndoAVF at follow-up.

CONCLUSIONS

The WavelinQ AVF system has a high initial procedural success rate, although a significant portion of patients require subsequent endovascular procedures to aid in maturation. Further work on determining factors predictive of need for reintervention is necessary.

Vascular Access and Risk of Bloodstream Infection Among Older Incident Hemodialysis Patients

Rationale & Objective

Most new patients with end-stage renal disease (ESRD) initiate hemodialysis (HD) with a central venous catheter (CVC) and later transition to a permanent vascular access with lower infection risk. The benefit of early fistula use in preventing severe infections is incompletely understood. We examined patients' first access and subsequent transitions between accesses during the first year of HD to estimate the risk for bloodstream infection (BSI) associated with incident and time-dependent use of HD access.

Study Design

A retrospective cohort study using enhanced 5% Medicare claims data.

Setting & Participants

New patients with ESRD initiating HD between January 1, 2011, and December 31, 2012, and having complete pre-ESRD Medicare fee-for-service coverage for 2 years.

Exposure

The incident and prevalent use of CVC, graft, or fistula as determined from monthly reports to the Centers for Medicare & Medicaid Services by HD providers.

Outcome

Incident hospitalization with a primary/secondary diagnosis of BSI (International Classification of Diseases, Ninth Revision, Clinical Modification code 038.xx or 790.7).

Analytical Approach

Extended survival analysis accounting for patient confounders.

Results

Of 2,352 study participants, 1,870 (79.5%), 77 (3.3%), and 405 (17.2%) initiated HD with a CVC, graft, and fistula, respectively. During the first year, the incident BSI hospitalization rates per 1,000 person-days were 1.3, 0.8, and 0.3 (P<0.001) in patients initiating with a CVC, graft, and fistula, respectively. After adjusting for confounders, incident fistula use was associated with 61% lower risk for BSI (HR, 0.39; 95% CI, 0.28-0.54; P<0.001) compared with incident CVC or graft use. The prevalent fistula or graft use was associated with lower risk for BSI compared with prevalent CVC use (HRs of 0.30 [95% CI, 0.22-0.42] and 0.47 [95% CI, 0.31-0.73], respectively).

Limitations

Restricted to an elderly population; potential residual confounding.

Conclusions

Incident fistula use was associated with lowest rates of BSI, but the majority of beneficiaries with pre-ESRD insurance initiated HD with a CVC. Strategies are needed to improve pre-ESRD fistula placement.

2018 Infectious Diseases Society of America Clinical Practice Guideline for the Management of Outpatient Parenteral Antimicrobial Therapy

A panel of experts was convened by the Infectious Diseases Society of America (IDSA) to update the 2004 clinical practice guideline on outpatient parenteral antimicrobial therapy (OPAT) [1]. This guideline is intended to provide insight for healthcare professionals who prescribe and oversee the provision of OPAT. It considers various patient features, infusion catheter issues, monitoring questions, and antimicrobial stewardship concerns. It does not offer recommendations on the treatment of specific infections. The reader is referred to disease- or organism-specific guidelines for such support.

Quality assessment of vascular access procedures for hemodialysis: A position paper of the Vascular Access Society based on the analysis of existing guidelines

Quality assessment in vascular access procedures for hemodialysis is not clearly defined. The aim of this article is to compare various guidelines regarding recommendation on quality control in angioaccess surgery. The overall population of end-stage renal disease patients and patients in need for hemodialysis treatment is growing every year. Chronic intermittent hemodialysis is still the main therapy. The formation of a functional angioaccess is the cornerstone in the management of those patients. Native (autologous) arteriovenous fistula is the best vascular access available. A relatively high percentage of primary failure and fistula abandonment increases the need for quality control in this field of surgery. There are very few recommendations of quality assessment on creation of a vascular access for hemodialysis in the searched guidelines. Some guidelines recommend the proportion of native arteriovenous fistula in incident and prevalent patients as well as the maximum tolerable percentage of central venous catheters and complications. According to some guidelines, surgeon’s experience and expertise have a considerable influence on outcomes. There are no specific recommendations regarding surgeon’s specialty, grade, level of skills, and experience. In conclusion, there is a weak recommendation in the guidelines on quality control in vascular access surgery. Quality assessment criteria should be defined in this field of surgery. According to these criteria, patients and nephrologists could choose the best vascular access center or surgeon. Centers with best results should be referral centers, and centers with poorer results should implement quality improvement programs.

Successful AV Fistula Creation does not Lead to Higher Catheter Use: The Experience by the Northwest Renal Network 16 Vascular access Quality Improvement Program. Four Years follow-up

Background

In 2002, the Center for Medicare and Medicaid Services (CMS) required all 18 Renal Networks to participate in a Vascular Access Quality Improvement Program (QIP). The Northwest Renal Network (NWRN 16) chose to increase arteriovenous fistula (AVF) use. NWRN 16 hypothesized that strategies which targeted the improvement of AVF rate and the reduction of catheter use were the same. In December 2001, 44.2% of hemodialysis (HD) patients in the NWRN 16 received HD using an AVF which met the Dialysis Outcome Quality Initiative (K/DOQI) 40% AVF guideline for prevalent patients. However, 43% of HD facilities (2869 patients) had less than 40% of AVF and higher HD catheter rates than the average Network catheter rates (25.0 vs. 20.3%). To address the needs of underperforming facilities, NWRN 16 provided education and tools for their vascular access decision makers to promote AVF creation and catheter reduction.

Methods

In 2002, NWRN 16 sponsored four regional workshops targeted at nephrologists, vascular surgeons, HD nurses, and interventional radiologists.

Results

Percentage of AVFs in use in invited facilities increased from 31.3% pre-intervention to 56.2% at 4 yrs: 78% increase (99% confidence interval: 77.8% to 81.5%). Percentage of catheters increased from 25% to 25.8%: 3.2% change over 4 yrs (99% confidence interval: 2.5% to 4%).

Conclusion

The success of Network 16's AVF interventions demonstrates the effectiveness of Network education promoting multidisciplinary teamwork, and innovative strategies to increase dramatically AVF use without substantial increase in catheter use.

Vascular Access Practice Patterns in Canada: A National Survey

Background:

One of the mandates of the Canadian Society of Nephrology’s (CSN) Vascular Access Working Group (VAWG) is to inform the nephrology community of the current status of vascular access (VA) practice within Canada. To better understand VA practice patterns across Canada, the CSN VAWG conducted a national survey.

Objectives:

(1) To inform on VA practice patterns, including fistula creation and maintenance, within Canada. (2) To determine the degree of consensus among Canadian clinicians regarding patient suitability for fistula creation and to assess barriers to and facilitators of fistula creation in Canada.

Design:

Development and implementation of a survey.

Setting:

Community and academic VA programs.

Participants:

Nephrologists, surgeons, and nurses who are involved in VA programs across Canada.

Measurements:

Practice patterns regarding access creation and maintenance, including indications and contraindications to fistula creation, as well as program-wide facilitators of and barriers to VA.

Methods:

A small group of CSN VAWG members determined the scope and created several VA questions which were then reviewed by 5 additional VAWG members (4 nephrologists and 1 VA nurse) to ensure that questions were clear and relevant. The survey was then tested by the remaining members of the VAWG and refinements were made. The final survey version was submitted electronically to relevant clinicians (nephrologists, surgeons, and nurses) involved or interested in VA across Canada. Questions centered around 4 major themes: (1) Practice patterns regarding access creation (preoperative assessment and maturation assessment), (2) Practice patterns regarding access maintenance (surveillance and salvage), (3) Indications and contraindications for arteriovenous (AV) access creation, and (4) Facilitators of and barriers to fistula creation and utilization.

Results:

Eighty-two percent (84 of 102) of invited participants completed the survey; the majority were nurses or VA coordinators (55%) with the remainder consisting of nephrologists (21%) and surgeons (20%). Variation in practice was noted in utility of preoperative Doppler ultrasound, interventions to assist nonmaturing fistulas, and procedures to salvage failing or thrombosed AV-access. Little consensus was seen regarding potential contraindications to AV-access creation (with the exception of limited life expectancy and poor vasculature on preoperative imaging, which had high agreement). Frequent barriers to fistula utilization were primary failure (77% of respondents) and long maturation times (73%). Respondents from centers with low fistula prevalence also cited long surgical wait times as an important barrier to fistula creation, whereas those from centers with high fistula prevalence cited access to multidisciplinary teams and interventional radiology as keys to successful fistula creation and utilization.

Conclusions:

There is significant variation in VA practice across Canada and little consensus among Canadian clinicians regarding contraindications to fistula creation. Further high-quality studies are needed with regard to appropriate fistula placement to help guide clinical practice.

Cumulative patency of contemporary fistulas versus grafts (2000-2010)

BACKGROUND AND OBJECTIVES

Comparisons of fistulas and grafts often overlook the high primary failure rate of fistulas. This study compared cumulative patency (time from access creation to permanent failure) of fistulas and grafts.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Vascular accesses of 1140 hemodialysis patients from two centers (Toronto and London, Ontario, Canada, 2000-2010) were analyzed. Cumulative patency was compared between groups using Kaplan-Meier survival curves and log-rank tests. Hazard ratios (HRs) for fistula failure relative to grafts and 95% confidence intervals (95% CIs) are reported.

RESULTS

There were 1012 (88.8%) fistulas and 128 (11.2%) grafts. The primary failure rate was two times greater for fistulas than for grafts: 40% versus 19% (P<0.001). Cumulative patency did not differ between fistulas and grafts for the patients' first access (median, 7.4 versus 15.0 months, respectively [HR, 0.99; 95% CI, 0.79-1.23; P=0.85]) or for 600 with a subsequent access (7.0 versus 9.0 months [HR, 0.93; 95% CI, 0.77-1.13; P=0.39]). However, when primary failures were excluded, cumulative patency became significantly longer for fistulas than for grafts for both first and subsequent accesses (61.9 versus 23.8 months [HR, 0.56; 95% CI, 0.43-0.74; P<0.001] and 42.8 versus 15.9 months [HR, 0.56; 95% CI, 0.44-0.72; P<0.001]). Results were similar for forearm and upper-arm accesses. Compared with functioning fistulas, grafts necessitated twice as many angioplasties (1.4 versus 3.2/1000 days, respectively; P<0.001) and significantly more thrombolysis interventions (0.06 versus 0.98/1000 days; P<0.001) to maintain patency once matured and successfully used for dialysis.

CONCLUSIONS

Cumulative patency did not differ between fistulas and grafts; however, grafts necessitated more interventions to maintain functional patency.

The role of the primary care physician in managing early stages of chronic kidney disease

Recent increases in obesity, diabetes, and hypertension, along with the aging of the US population, are driving a dramatic rise in the prevalence of chronic kidney disease (CKD). Despite this increase, the majority of Americans with early-stage CKD remain unaware of their disease. Primary care physicians are at the forefront of efforts for early recognition of CKD and management to control its progression. Patients with CKD should be referred to nephrologists no later than the point at which their estimated glomerular filtration rate reaches 30 mL/min. Nephrology evaluation at this point is essential to facilitate timely preparation for care of end-stage renal disease through preemptive transplantation or planned transition to dialysis. In addition to stringent control of underlying hypertension and/or diabetes, mineral metabolic parameters (serum parathyroid hormone, phosphorus, calcium, and bicarbonate) in patients with advancing CKD should be managed closely to avoid adverse effects on the cardiovascular and skeletal systems.

Time to move away from damage control strategy in hemodialysis vascular access management: a view from Saudi Arabia

For the last 40 years, most of the research and publications on hemodialysis access, has focused on the management of its complications e.g. thrombosis, infection, aneurysms. In other words, a damage control strategy. While this is undoubtedly an important part of access management, it is a deficient reactive strategy that does not enhance a better quality of life for patients or help reduce the burden on health care resources. To achieve these objectives, efforts should be directed at ways which provide a longer access life with fewer complications. Such an approach would save costs and reduce the suffering of the patient. In this paper we will focus on hemodialysis management in Saudi Arabia, describe the reasons for the current unsatisfactory situation, and highlight possible remedies.

Increasing the proportion of autologous arteriovenous fistulas does not diminish fistula patency

OBJECTIVE

Arteriovenous fistulas (AVF) constructed before and after initiating the kidney disease outcomes and quality initiative (KDOQI) guidelines were reviewed at a single academic center to identify decreased patency with use of potentially inferior vein conduits.

METHODS

Primary access procedures performed pre- and post-adoption of KDOQI guidelines were compared for the primary outcomes of maturation rate and primary patency and the secondary outcome of access utilization.

RESULTS

The proportion of autologous AVFs created was higher post-KDOQI (73% vs 35%, P < .001), and an increased use of the basilic vein was observed (20% vs 2%, P < .05). The failure rate of fistula maturation was reduced post-KDOQI (24% vs 38%, P < .05); however, access utilization was also decreased (59% vs 75%, P < .001).

CONCLUSIONS

Adherence to KDOQI guidelines for AVFs does not compromise fistula patency and increased use of the basilic vein may lead to superior fistula maturation rates. Early referral may result in lower fistula utilization rates, however.

Variation in fistula use across dialysis facilities: is it explained by case-mix?

BACKGROUND AND OBJECTIVES

Arteriovenous fistulas (AVFs) remain the preferred vascular access for hemodialysis patients. Dialysis facilities that fail to meet Centers for Medicare & Medicaid Services goals cite patient case-mix as a reason for low AVF prevalence. This study aimed to determine the magnitude of the variability in AVF usage across dialysis facilities and the extent to which patient case-mix explains it.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The vascular access used in 10,112 patients dialyzed at 173 Dialysis Clinic Inc. facilities from October 1 to December 31, 2004, was evaluated. The access in use was considered to be an AVF if it was used for >70% of hemodialysis treatments. Mixed-effects models with a random intercept for dialysis facilities evaluated the effect of facilities on AVF usage. Sequentially adjusted multivariate models measured the extent to which patient factors (case-mix) explain variation across facilities in AVF rates.

RESULTS

3787 patients (38%) were dialyzed using AVFs. There was a significant facility effect: 7.6% of variation in AVF use was attributable to facility. This was reduced to 7.1% after case-mix adjustment. There were no identified specific facility-level factors that explained the interfacility variation.

CONCLUSIONS

AVF usage varies across dialysis facilities, and patient case-mix did not reduce this variation. In this study, 92% of the total variation in AVF usage was due to patient factors, but most were not measurable. A combination of patient factors and process indicators should be considered in adjudicating facility performance for this quality indicator.

Status of initiating pattern of hemodialysis: a multi-center study

This study was to evaluate the status of initiating pattern of hemodialysis (HD). Five hundred-three patients in 8 University Hospitals were included. Presentation mode (planned vs. unplanned), and access type (central venous catheters [CVC] vs. permanent access) at initiation of HD were evaluated, and the influence of predialysis care on determining the mode of HD and access type was also assessed. Most patients started unplanned HD (81.9%) and the most common initial access type was CVC (86.3%). The main reason for unplanned HD and high rate of CVC use was patient-related factors such as refusal of permanent access creation and failure to attend scheduled clinic appointments. Predialysis care was performed in 57.9% of patients and only 24.1% of these patients started planned HD and 18.9% used permanent accesses initially. Only a minority of patients initiated planned HD with permanent accesses in spite of predialysis care. To overcome this, efforts to improve the quality of predialysis care are needed.

Gender differences in vascular access in hemodialysis patients in the United States: developing strategies for improving access outcome

BACKGROUND

Patients undergoing chronic hemodialysis (HD) require placement of permanent vascular access with the creation of an arteriovenous fistula (AVF), an arteriovenous prosthetic graft (AVG), or a tunneled central venous catheter. AVFs provide greater long-term patency, fewer complications, and lower infection rates than do either AVGs or catheters. Despite these advantages, women continue to be underrepresented among AVF patients, possibly because of concerns about smaller vascular diameters and higher rates of early primary fistula failure in female HD patients. The numerous clinical benefits of AVF suggest that a greater effort should be made to promote AVF placement in women.

OBJECTIVE

This review analyzes risk factors for AVF failure in women and describes clinical strategies to improve AVF utilization and success for female HD patients.

METHODS

English-language publications were identified through a MEDLINE database search from January 1997 to March 2007, using the search terms arteriovenous fistula, vascular access, hemodialysis, female, and gender. Reference lists of identified articles were also reviewed.

RESULTS

There are significant benefits to using AVFs instead of AVGs or catheters in HD patients: greater long-term fistula patency, superior flow rates, and fewer complications. Vascular anatomical differences between the sexes contribute to the underutilization of AVF in women. AVF placement rates can be improved if patients and staff are adequately educated and provided with the tools to facilitate AVF placement. Noninvasive preoperative screening is important to identify superior access sites in women. Intraoperative monitoring of blood flow is a reliable predictor of early radiocephalic AVF patency. Routine postoperative vascular monitoring may improve overall success with AVF, and exercise may improve vascular diameter and may be even more beneficial for women, who may have smaller preoperative veins.

CONCLUSIONS

Concerns about smaller vascular diameters and reports of higher failure rates in women may prevent nephrologists and surgeons from considering AVF for female HD patients. The numerous advantages associated with AVF suggest that a greater effort should be made to increase its utilization in women. With appropriate motivation, care, and diligence by treating clinicians, the success of AVFs in women can approach the good results typically expected in men.

Infections associated with long-term prosthetic devices

The extensive and ever-increasing use of long-term prosthetic devices has improved quality of life and survival for many patients. Prosthetic device-related infection occurs infrequently but is associated with significant morbidity and mortality. Management is challenging, often requiring prolonged antimicrobial therapy and surgical intervention. Better understanding of the interaction between microorganisms, devices, and the host should improve the ability to manage device-related infections. This article reviews recent advances in the diagnosis and treatment of infections associated with indwelling medical devices, highlighting those associated with prosthetic joints, cerebrospinal fluid shunts, and prosthetic heart valves.

Cancer chemotherapy administered via hemodialysis fistulas

End-stage renal failure (ESRF) patients can develop cancer before or after kidney disease occurs. Cancer chemotherapy often needs to be administered via the sort of central venous catheter that is normally avoided in ESRF care. Three cases are presented in which ESRF patients received chemotherapy for cancer via existing hemodialysis fistulas, and the consequences of central venous access in a fourth patient are discussed.