Management of hemodialysis access infections

Axillary necklace graft salvage of a locally infected Haemodialysis with Reliable Outflow (HeRO®) graft

BACKGROUND

A 48-year-old patient presented 4 months after insertion of a right sided Haemodialysis with Reliable Outflow (HeRO®, Merit Medical) graft with a discharging abscess at the site of the brachial artery anastomosis. There was localised involvement of the arterial Gore® Acuseal inflow graft that necessitated its removal. The venous outflow component was thought salvageable as infection was well localised to the region of the antecubital fossa.

OBJECTIVES

Alternative access options were limited so we sought to preserve the venous outflow portion of the patient's original graft - minimising tissue damage and avoiding the need for a dialysis line.

METHODS

The infected arterial graft was excised, leaving behind the original SuperHero® connector and venous graft. A left sided tunnelled axillary necklace technique was utilised to restore arterial inflow.

RESULTS

After a four-day recovery, the patient went on to successfully resume their usual haemodialysis regimen without any complications. Convalescent imaging, repeat blood cultures, and monitoring of inflammatory markers showed no signs of residual infection at 6 weeks.

CONCLUSIONS

The originality of this case was the way in which an axillary necklace inflow graft was connected to the pre-existing venous outflow portion of the HeRO® haemodialysis graft system, allowing the excision of the infected inflow graft at the brachial anastomosis. This technique could be viewed as an effective salvage procedure as it allowed the venous outflow portion of the original graft to remain in situ, minimised tissue damage and enabled the patient to swiftly resume haemodialysis without the need for a line.

Guidelines on vascular access for hemodialysis from the Brazilian Society of Angiology and Vascular Surgery

Chronic kidney disease is a worldwide public health problem, and end-stage renal disease requires dialysis. Most patients requiring renal replacement therapy have to undergo hemodialysis. Therefore, vascular access is extremely important for the dialysis population, directly affecting the quality of life and the morbidity and mortality of this patient population. Since making, managing and salvaging of vascular accesses falls within the purview of the vascular surgeon, developing guideline to help specialists better manage vascular accesses for hemodialysis if of great importance. Thus, the objective of this guideline is to present a set of recommendations to guide decisions involved in the referral, evaluation, choice, surveillance and management of complications of vascular accesses for hemodialysis.

Management of Arteriovenous Graft Infection

Objective: Arteriovenous graft (AVG) infection influences the survival and quality of life of patients, causing life-threatening sepsis reducing dialysis access. This study aimed to evaluate an appropriate treatment strategy for AVG infection. Methods: We analyzed 61 cases involving AVG infections identified at a single center. The cases were divided into two groups based on the type of AVG and surgical methods, namely, currently used AVG (cAVG) (n=29) or abandoned AVG (aAVG) (n=32) and total graft excision (TGE) (n=10) or partial graft excision (PGE) (n=46). Results: There was a significant difference in lower procedure frequency (p<0.001) and longer procedure time (p=0.014) in the cAVG group. A significant difference in lower reinfection rate (p=0.009) was found in the TGE group. Multivariable analysis confirmed that aAVG significantly independently affected the reinfection rate (hazard ratio, 2.208; 95% confidence interval, 1.069-4.561; p=0.032). Staphylococcus aureus was the most frequent cause of AVG infection (61.5%); 77.5% of Staphylococcus aureus were methicillin-resistant Staphylococcus aureus. Conclusion: We found a higher risk of reinfection after PGE than TGE, and aAVG infection was associated with approximately two times higher likelihood of reinfection. These findings suggest that TGE should be considered for patients with AVG infections, particularly aAVG infections.

Brachial artery transposition versus catheters as tertiary vascular access for maintenance hemodialysis: a single-center retrospective study

Some hemodialysis patients are not suitable for creation of an arteriovenous fistula (AVF) or arteriovenous graft (AVG). However, they can receive a tunneled cuffed central venous catheter (tcCVC), but this carries risks of infection and mortality. We aimed to evaluate the safety and effectiveness of brachial artery transposition (BAT) versus those of tcCVC. This retrospective study evaluated hemodialysis patients who underwent BAT or tcCVC placement because of severe heart failure, hand ischemia, central venous stenosis or occlusion, inadequate vessels for creating standard arteriovenous access, or limited life expectancy. The primary outcome was whole access circuit patency. Thirty-eight patients who underwent BAT and 25 who underwent tcCVC placement were included. One-year patency rates for the whole access circuit were 84.6% and 44.9% in the BAT and tcCVC groups, respectively. The BAT group was more likely to maintain patency (unadjusted hazard ratio: 0.17, 95% confidence interval: 0.05–0.60, p = 0.006). The two groups did not have significantly different overall survival (log-rank p = 0.146), although severe complications were less common in the BAT group (3% vs. 28%, p = 0.005). Relative to tcCVC placement, BAT is safe and effective with acceptable patency in hemodialysis patients not suitable for AVF or AVG creation.

Puncture Site Necrosis Over Hemodialysis Native and Prosthetic Vascular Accesses

BACKGROUND

The aim of this study was to detail our experience in the management of skin necrosis/ulceration over hemodialysis vascular accesses.

METHODS

We collected demographics and operative data about patients undergoing surgery for skin necrosis over native or prosthetic vascular accesses. The different procedural techniques used and outcomes achieved were analyzed.

RESULTS

Over a six-year period (2013-2019), 593 hemodialysis accesses were created and 16 patients (50%, 8 male; median age 63.6 years, range 42-87; 12 native and 4 prosthetic accesses) were emergently/urgently treated for skin necrosis with danger of rupture (n 9), minor active bleeding (n 4) or life-threatening hemorrhage (n 3). Underlying causes were local infection, aneurysm/pseudo-aneurysm formation and venous stenosis. Most accesses were preserved. Rescue procedures consisted in excision of skin necrosis in association with aneurysmorrhaphy (n 1, 6.3%), simple closure of the venous breach (n 2, 12.5%) or resection and direct re-anastomosis (n 7, 43.8%). Concomitant endoluminal dilatation of venous outflow was needed in 7 (43.8%) cases. No intraoperative complications were observed. At a median of 13 months (range 1-39), 90% of rescued accesses were still functional.

CONCLUSIONS

Skin necrosis/ulceration over vascular access requires prompt surgical intervention ahead the risk of life-threatening hemorrhage. The rescue of a functional access is possible in most patients and provides an efficient dialysis in postoperative period.

Nitinol stent-assisted maturation of the dysfunctional cannulation zone in the immature arteriovenous fistula

INTRODUCTION

The native arteriovenous fistula may remain immature despite adequate arterial inflow after formation. This may occur when the puncturable vein segment (cannulation zone) is too small to be reliably punctured, occluded or too deep under the skin for needle access. We performed stenting (stent-assisted maturation) of arteriovenous fistulas with an immature cannulation zone, allowing for a large subcutaneous channel which could then be immediately punctured for dialysis.

METHODS

We performed a retrospective review of 49 patients (mean age was 58.7 ± 16.09 (12-83) years, mean arteriovenous fistula age of 162.6 ± 27.28 days) with end-stage renal failure who underwent balloon dilatation and bare-metal stent implantation (1.6 ± 0.67 (1-3) stents, median diameter and length of 8 (5-14) mm and 80 (40-150) mm, respectively) through their cannulation zone (forced maturation). Radiocephalic (35 arteriovenous fistulas), brachiocephalic (10 arteriovenous fistulas) and autogenous loop arteriovenous fistulas (4 arteriovenous fistulas) were included with 30 patients (61.2%) having an inadequate cannulation zone venous diameter, 9 patients (18.4%) having an absent cannulation zone and 10 patients (20.4%) having a patent cannulation zone deeper than 1 cm which was not reliably puncturable. The study was conducted over 9 years (January 2008-December 2016) with implantation of the SMART^® stent and Absolute Pro^® stent in 61.2% and 38.8%, respectively. Long-term outcomes including primary useable segmental and access circuit patency as well as assisted primary access circuit patency, rate of re-intervention, technical success and complications were analysed.

RESULTS

At 6 months, 12 months and 4 years, respectively, cannulation zone primary patency was 84.4%, 74.4% and 56.1% and access circuit primary patency was 62.2%, 45.3% and 23.2%; however, assisted primary access circuit patency was 95.6%, 91.1% and 83.8%, achieved with an endovascular re-intervention rate of 0.53 procedures/year with only four thrombosed circuits occurring.

DISCUSSION

Forced maturation using nitinol stents allows for long-term haemodialysis access with a low rate of re-intervention.

Prevalence of infections and antimicrobial use among hemodialysis outpatients: A prospective multicenter study

Hemodialysis patients are vulnerable to infectious diseases and frequent receipt of antimicrobial agents. The aim of this study was to describe the prevalence and characteristics of infections and antimicrobials use among hemodialysis outpatients. We utilized the dialysis event surveillance protocol developed by the National Healthcare Safety Network to conduct a prospective multicenter study in Anhui, China. A total of 41 dialysis centers involving 7393 outpatients were included. Fistula was the most common type of vascular access (85.3%), followed by tunneled central line (12.7%), and non-tunneled central line (1.2%). There were 118 dialysis events with an overall pooled events rate of 1.60 per 100 patient-months. Intravenous antimicrobial start, positive blood culture, and pus, redness, or increased swelling at the vascular access site were detected at rates of 0.91, 0.23, and 0.46 per 100 patient-months, respectively. The prevalence of dialysis events was commonly higher in patients with a central line, and lower in patients with a fistula. Hemodialysis outpatients also had the noteworthy risks of nonaccess infections. Older age, female gender, and having a central line were associated with the increased risk of dialysis events. Findings recommend that regular monitoring and improvement strategies are warranted in management of infections among hemodialysis outpatients.

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.

Long-term results of thigh arteriovenous dialysis grafts

INTRODUCTION:

A proportion of hemodialysis patients exhaust all options for arteriovenous access in upper extremities. Arteriovenous thigh grafts are a potential vascular access option in such patients.

METHODS:

We performed a retrospective study of all thigh arteriovenous access grafts placed between 1995 and 2015. The clinical, demographic patient information and patency of each thigh graft was determined from the time of surgical creation placement until abandonment, transfer to other modality, or center or end of study, and the reason for access failure documented.

RESULTS:

In total, 44 patients received 49 thigh arteriovenous accesses. The average age was 60 years (13-79 years); Half (53%) of the patients (n = 24) were female and 61% of the patients (n = 30) of arteriovenous accesses were left-sided. The cumulative proportion surviving (primary patency rates) at 12, 24, and 28 months were 43% (standard error = 9%), 33% (standard error = 9%), and 13% (standard error = 9%), respectively. The cumulative proportion of surviving grafts at 12, 24, and 48 months were 61% (standard error = 8%), 58% (standard error = 9%), and 31% (standard error = 13%), respectively. In total, 37 revisions were performed in 22 patients to maintain patency or eradicate infection. Infection occurred in 20 patients (39%) of thigh grafts requiring 16 patients (80% of those affected) to be removed; 14 patients had grafts (33.3%) that served as the lone hemodialysis arteriovenous access during the patients' lifetime on dialysis.

CONCLUSION:

Arteriovenous thigh graft access is used infrequently, but they have an acceptable patency. Some accesses require revisions and they have a high infection rate. Despite this, an acceptable proportion of leg grafts provide durable access for the dialysis lifetime of the patient.

How to treat arteriovenous graft infection: total versus partial graft excision

Introduction:

Arteriovenous graft (AVG) infection can result in life-threatening sepsis and loss of vascular access. A retrospective study was performed to establish an appropriate treatment strategy for AVG infection.

Methods:

A total of 50 cases of AVG infection were treated between January 2005 and June 2016. The surgical methods used were total graft excision (TGE) (n = 34), or partial graft excision (PGE) with interposition graft (n = 16).

Results:

Infection was noted at a puncture site (n = 22), a prior incision for surgery or endovascular therapy (n = 20), and abandoned (currently unused) grafts (n = 5). Infection occurred within 1 month after AVG creation (n = 1), or any intervention (n = 14), and more than 1 month after creation or intervention (n = 35). Simultaneous remote infection was identified in 7 patients, 2 of whom underwent an operation for infective endocarditis and spondylitis. After PGE, 5 patients (5/16, 31.2%) having recurrent infection were treated with further graft excision; however, no patient showed life-threatening complications. After TGE, a central venous catheter (CVC) was inserted and used for a median period of 90 days. Among 34 patients who underwent TGE, new vascular access was created in 18 patients at a median period of 2 months later, and 12 patients continued to use a CVC until last follow-up or death.

Conclusions:

PGE could be a treatment option for AVG infection to achieve both infection eradication and vascular access preservation in selected patients. Because of a higher risk of recurrent infection, sufficient surgical removal and careful postoperative management are warranted.

Treatment of dialysis catheter infections in 2004

Hemodialysis catheter associated infections are a major source of morbidity and mortality in end stage renal disease patients. There is disagreement about the management of catheter infections, particularly concerning the removal of potentially infected tunneled dialysis catheters. A dialysis catheter should generally be removed when an infection involves a temporary hemodialysis catheter, a septic patient, a patient with a tunnel tract infection, or a patient with evidence of a metastatic infectious complication. In treating stable patients with clinically mild catheter associated bacteremia, parenteral antibiotics alone have a low success rate in eliminating the infection. Antibiotic locks are an emerging strategy for treating these patients, but at present higher rates of success and lower costs are achieved by exchanging the catheter over a guidewire. Antibiotic lock solutions, antibiotic coated catheters, and totally implantable dialysis access systems may play a large role in prevention of catheter associated infections in the future; however, further randomized controlled trials of these strategies are needed. Future efforts should concentrate on limiting the use of traditional tunneled cuffed hemodialysis catheters by early referral to vascular surgery for the creation of an arterio-venous fistula.

A Retrospective Analysis of Dialysis Events over a 3-Year Period in an Outpatient Dialysis Unit in the State of Kuwait

OBJECTIVE

To determine the difference in the rates of dialysis events stratified by vascular access type and to describe the microbiological profile and sensitivity patterns of positive blood cultures over a 3-year period.

SUBJECTS AND METHODS

The dialysis event data of 10,751 chronic hemodialysis patients collected from March 2013 to February 2016 at an outpatient dialysis unit in Kuwait were reviewed. The dialysis events studied were: intravenous (IV) antimicrobial use, a positive blood culture, and signs of inflammation at the vascular access site. Dialysis event rates were stratified by the type of vascular access used for the dialysis, i.e., fistula, graft, and tunneled/nontunneled central line. Rates were expressed per 100 patient-months.

RESULTS

The overall dialysis event rate was (10.7/100 patient-months). The rate of IV antimicrobial use was higher (12.53/100 patient-months) in patients with tunneled central lines than in all other vascular access types (10.29/100 patient-months). Positive blood culture and inflammation at the vascular access site were highest in patients with nontunneled central lines (1.65 and 1.54/100 patient-months, respectively) when compared to those with other types of vascular access. Gram-negative rod isolates were predominant in patients with central lines (n = 35; 46.67%); however, common skin commensals and gram-negative rods were also identified in patients with fistula or graft (n = 4; 44.45%).

CONCLUSION

Dialysis event rates were higher among patients with tunneled or nontunneled central lines than in patients with fistula or graft. Gram-negative rods were the most commonly isolated microbial group.

Operative and perioperative management of infected arteriovenous grafts

Vascular graft infections are a particularly troublesome complication for dialysis patients, many of whom are in an already immunocompromised state. The objective of this review is to detail the risk factors, etiology, diagnosis, perioperative and operative management of vascular graft infections.

Risk Factors for Infectious Spondylodiscitis in Patients Receiving Hemodialysis

A retrospective case-control and cohort analysis of hemodialysis patients was done to identify risk factors for spondylodiscitis. These risk factors included bacteremia, receipt of blood products, invasive procedures, and establishment of vascular access. The death rate was greater for case subjects than for control subjects (odds ratio, 2.7).

Which accesses should be abandoned or revised?

This review considers the factors in deciding whether to abandon a functioning access. Strong indications for ligation or excision of an access are infection or severe early-onset steal. Access ligation may also be required for central vein occlusion or high-output cardiac failure. In general, a failing or thrombosed access should be restored to function unless it is no longer required. For failing or thrombosed distal arteriovenous fistulas, it may be easiest to abandon it and create a new fistula a few centimetres proximally rather than perform angioplasty, which is likely to require repeating. Other accesses may be abandoned after repeated treatment of the same stenosis over a short period provided other options exist.

[Treatment of complications after arteriovenous access surgery]

The choice of potential options for an arteriovenous (AV) access is limited for each individual patient. Complications shorten the maximum life span of any AV access. This paper stresses the importance of recognizing complications in time so as to initiate early and adequate therapy which are explained in further detail. Existing vascular accesses should be used as long as possible while maintaining further alternatives for future AV access surgery.

The in vivo stability of electrospun polycaprolactone-collagen scaffolds in vascular reconstruction

To avoid complications of prosthetic vascular grafts, engineered vascular constructs have been investigated as an alternative for vascular reconstruction. The scaffolds for vascular tissue engineering remain a cornerstone of these efforts and yet many currently available options are limited by issues of inconsistency, poor adherence of vascular cells, or inadequate biomechanical properties. In this study, we investigated whether PCL/collagen scaffolds could support cell growth and withstand physiologic conditions while maintaining patency in a rabbit aortoiliac bypass model. Our results indicate that electrospun scaffolds support adherence and growth of vascular cells under physiologic conditions and that endothelialized grafts resisted adherence of platelets when exposed to blood. When implanted in vivo, these scaffolds were able to retain their structural integrity over 1 month of implantation as demonstrated by serial ultrasonography. Further, at retrieval, these scaffolds continued to maintain biomechanical strength that was comparable to native artery. This study suggests that electrospun scaffolds combined with vascular cells may become an alternative to prosthetic vascular grafts for vascular reconstruction.

Hemodialysis for the non-nephrologist

Hemodialysis is now routinely provided to more than 300,000 patients in the United States. An epidemic of end-stage renal disease will nearly double this number by 2010. Patients undergoing chronic hemodialysis have high morbidity and mortality rates. Given these facts, most medical providers will be involved in the care of patients undergoing hemodialysis and it is thus important to have an understanding of the dialysis procedure and its attendant risks. This review discusses the basic physiology of the dialysis procedure and its associated complications.