Version May 2024
INTRODUCTION — The goal of chronic hemodialysis access is to provide repeated access to the circulation with minimal complications. Decisions surrounding the initial choice of chronic hemodialysis access are complex and should be to maximize the likelihood of providing a functional access within a reasonable period of time, minimizing complications during creation and access use, maximizing options for lifelong access, and taking into consideration patient preferences.
An overall approach for establishing vascular access in the patient needing chronic hemodialysis is reviewed. Creating an arteriovenous (AV) hemodialysis access (AV fistula, AV graft) and placement and management of hemodialysis catheters are reviewed separately. (See "Arteriovenous fistula creation for hemodialysis and its complications" and "Arteriovenous graft creation for hemodialysis and its complications" and "Central venous catheters for acute and chronic hemodialysis access and their management".)
CHRONIC HEMODIALYSIS ACCESS
Types of access — The three principal forms of chronic hemodialysis access are arteriovenous (AV) fistulas, AV grafts, and hemodialysis catheters [1,2].
Hemodialysis access is most commonly attained using vessels in the upper extremities. The lower extremity is a less commonly used access site [3-5]. The upper chest can be used when extremity sites have been exhausted. Finally, central venous catheters can be inserted into the inferior vena cava via translumbar or transhepatic routes if all other locations have been exhausted [6].
Arteriovenous fistulas — An AV fistula is a deliberate connection between a native artery and vein and is typically constructed with an end-to-side, vein-to-artery anastomosis. The most commonly used AV fistulas are created by anastomosing the radial artery to the cephalic vein (radiocephalic fistula) or by anastomosing the brachial artery to the cephalic vein (brachiocephalic fistula). Brachiobasilic fistulas are also commonly created by anastomosing the brachial artery to the basilic vein, but this fistula is located deeper in the medial aspect of the upper arm and requires superficialization and lateral transposition for use. (See "Arteriovenous fistula creation for hemodialysis and its complications".)
Arteriovenous grafts — AV grafts are constructed by interposing graft material between an artery and vein. AV grafts are typically made of expanded polytetrafluoroethylene (ePTFE) and typically have a diameter of 6 mm (range, 4 to 8 mm). Allografts are also available as AV access conduits [7]. Common AV grafts include straight forearm (radial artery to cephalic vein), looped forearm (brachial artery to cephalic or brachial vein), straight upper arm (brachial artery to axillary vein), and looped upper arm (axillary artery to axillary vein). Early cannulation AV grafts are also available that can be used within one day of AV graft creation [8]. (See "Arteriovenous graft creation for hemodialysis and its complications".)
Central venous catheters — Chronic hemodialysis catheters are tunneled, cuffed central venous access devices. They are dual-lumen catheters constructed from polyurethane, silicone, or silicone composites. The lumen size generally ranges from 10 to 16 French. They are normally inserted into the internal jugular vein and tunneled through a subcutaneous tract with a Dacron cuff positioned under the skin proximal to the exit site. (See "Central venous catheters for acute and chronic hemodialysis access and their management".)
General comparison — Each type of vascular access has a unique set of risks and benefits. This section will focus on the differences that could affect decision making with respect to selection. Decision making should consider patient anatomy, ease of creation, ease of use, preservation of future access sites, risk of primary failure, expected patency, risk of complications during use, and patient preferences.
Ease of creation — Central venous catheters can be inserted in nearly all patients and are usually performed in interventional suites or special procedure rooms. Simple radiocephalic or brachiocephalic fistulas are typically created in the operating room with sedation under local anesthesia or regional nerve blocks. Studies have also described percutaneous fistula creation in the interventional suite, in the operating room, or in a procedure room using ultrasound alone [9-11]. Brachiobasilic fistulas and AV grafts are more extensive procedures and may require regional nerve blocks or a general anesthetic. Regional nerve block anesthesia provides a safe, comfortable anesthetic, and the associated vasodilation was shown in a randomized trial to improve the primary patency defined as thrill or bruit in the absence of any additional intervention to reestablish function of those fistulas [12]. Most of the failures in the local anesthetic group were loss of immediate patency at discharge from hospital, and there was no difference in functional patency at three months.
Some patients deemed to be at high surgical risk may not be candidates for more extensive surgery.
Primary failure — The risk of primary failure of AV fistulas is highly variable and has ranged from 47 to 60 percent in randomized trials, but the published rates depend heavily on the definition of failure [13,14]. The Hemodialysis Fistula Maturation Study, which was a prospective observational study, reported a risk of primary failure of 33 percent [15]. A meta-analysis that included 43 studies reported a lower rate at 23 percent [16]. To achieve a functional AV fistula, patients should be educated that additional interventions may be needed given the high risk of primary failure.
AV grafts have a lower risk of primary failure. In a study of 1012 AV fistulas and 128 AV grafts, the risk of primary failure for AV grafts was one half the risk of AV fistulas (19 versus 40 percent) [17]. A comparison of brachiocephalic fistulas, brachiobasilic fistulas, and upper arm AV grafts reported primary failure rates of 32, 21, and 15 percent, respectively [18]. In a retrospective study of 16,463 Medicare patients in the United States, repeat AV fistula/graft creation was required within one year for 27 percent among patients with AV fistulas compared with 17 percent among those with AV grafts [19]. It should be noted the risk of primary failure may be reduced by careful imaging of vessels to ensure adequate vessels for AV fistula creation [20,21].
Primary failure (or malfunction) of central venous catheters is rare, although they may fail immediately after insertion due to kinking or poor positioning. (See "Malfunction of chronic hemodialysis catheters".)
Cumulative patency — Cumulative (secondary) patency, either including or excluding primary failure, has been reported. When primary failure of AV fistulas is accounted for, cumulative patency of AV fistulas and AV grafts is similar up to three years from creation. As an example, in a review of 1140 hemodialysis patients with AV fistulas or AV grafts comprising a mixture of upper arm and lower arm locations, the cumulative patency did not differ significantly between AV fistulas and AV grafts as a first AV access (median 7.4 versus 15.0 months, respectively [hazard ratio 0.99, 95% CI 0.79-1.23]) [17]. A multicenter study from the Netherlands reported similar three-year cumulative patency rates (including primary failure) for radiocephalic fistulas (64 percent), brachiocephalic fistulas (75 percent), and upper arm (75 percent) [22]. Similar cumulative patencies were also found when brachiobasilic fistulas were compared with brachiocephalic fistulas and upper arms grafts [23]. In a decision analysis, AV fistulas had less benefit compared with AV grafts among older patients, particularly women with diabetes, reflecting their lower AV fistula success rates and lower life expectancy [24].
Complications — AV fistulas, once matured, are associated with the lowest complication rates, although some may require angioplasty to facilitate maturation or repeated angioplasty to maintain blood flow. Comparatively speaking, AV grafts have a higher risk of long-term complications, particularly stenosis at the venous anastomosis or thrombosis requiring repeated interventions. AV grafts can also be complicated by infection, whereas AV fistulas rarely have infections. AV grafts may have higher rates of initial dialysis-related steal syndrome. (See "Arteriovenous fistula creation for hemodialysis and its complications" and "Arteriovenous graft creation for hemodialysis and its complications" and "Hemodialysis access-induced distal ischemia".)
Central venous catheters have a high risk of complications after initial use, including low blood flow/thrombosis, mechanical complications (extruded cuffs, cracked lumens, catheters being pulled out accidentally), infectious complications (exit site/tunnel infections and bloodstream infections), and damage to central veins. Catheters often require exchanges and replacements to maintain access. In a retrospective review reporting complications that resulted in a procedure, hospitalization, or death, the cumulative risk of any catheter-related complications was 30 percent at one year and 38 percent at two years [25]. The one-year risk of bacteremia was 9 percent, and this was responsible for 72 percent of catheter-related hospitalizations. Symptomatic central venous stenosis or thrombosis requiring intervention occurred in 1.5 percent of patients, and blood flow restriction was responsible for 35 percent of procedures but did not result in any hospitalizations. (See "Malfunction of chronic hemodialysis catheters" and "Tunneled hemodialysis catheter-related bloodstream infection (CRBSI): Management and prevention" and "Central vein obstruction associated with upper extremity hemodialysis access".)
STRATEGY FOR LIFELONG HEMODIALYSIS ACCESS — The 2019 National Kidney Foundation Kidney Disease Outcomes Quality Initiative (KDOQI) Clinical Practice Guideline for Vascular Access Update states that care decisions surrounding hemodialysis access are often complex and should be individualized to promote patient-centered care using an interdisciplinary team composed of experienced nurses, nephrologists, radiologists, and vascular surgeons [26]. A lifelong access strategy in patients with end-stage kidney disease (ie, ESKD Life-Plan) begins with preserving veins for potential future access; carefully evaluating patients for initial arteriovenous (AV) access if hemodialysis is selected for renal replacement therapy; properly accessing, maintaining, and monitoring the access; and timely management of problems if they arise according to the patient's defined contingency and succession access plans [26]. The ESKD Life-Plan should be reviewed annually.
Patient-centered approach — Historically, AV fistulas were strongly promoted by guidelines because of their association with lower mortality, lower complication rates, and lower cost. These guidelines included the 2006 National Kidney Foundation Kidney Disease Outcomes Quality Initiative (updated in 2019 to promote a patient-centered approach [26]) [27], the Canadian Society of Nephrology (2006) [28], European Renal Best Practice (2007) [29], and Kidney Health Australia – Caring for Australasians with Renal Impairment (KHA-CARI; 2012) [30]. Furthermore, reimbursement has been tied to AV fistula use, particularly in the United States. However, a number of observations challenged the "fistula first" approach:
●The risk of primary AV fistula failure was observed to be approximately 50 percent in high-quality randomized studies [13,14].
●The benefit of AV fistulas was attenuated in higher risk populations. As an example, a study of 115,425 incident hemodialysis patients 67 years or older derived from the United States Renal Data System with linked Medicare claims did not detect a significant mortality difference between those patients who received a AV graft as the first access placed and those patients who received an AV fistula (hazard ratio [HR] 1.05, 95% CI 1.00-1.11) [31].
●The risk of selection bias in studies showing benefit for AV fistulas was very high. As a consequence, it was not clear if the better outcomes observed in patients using AV fistulas for vascular access were due to choice of vascular access or the fact that patients treated with AV fistulas were healthier and had a better prognosis [32]. As examples:
•In a retrospective cohort study of 2300 incident hemodialysis patients at five Canadian dialysis programs, a predialysis AV fistula creation was associated with a lower risk of all-cause mortality in patients under 65 years of age (HR 0.49, 95% CI 0.29-0.82) and in the first two years of follow-up in those age 65 years and older, but a higher risk thereafter (HR 0 to 24 months: 0.60, 95% CI 0.43-0.84; HR >24 months: 1.83, 95% CI 1.25-2.67) [33]. Importantly, only 2.3 percent of deaths were access related. When the authors compared outcomes between those who used their AV fistulas and those who used a catheter because their AV fistula attempts failed, there was no difference in mortality between the two groups. In other words, patients who were deemed fit for an AV fistula attempt had a survival advantage, independent of whether or not they ever used the AV fistula for hemodialysis. This again reinforces the idea that the excess mortality observed in hemodialysis patients treated with catheters may be the result of residual confounding, unmeasured comorbidity, or treatment selection bias, rather than an effect of the access itself.
•Similarly, a study from the United States of 90,517 patients who initiated dialysis with a catheter or AV fistula found a significant mortality benefit among those treated with AV fistulas (HR 0.50, 95% CI 0.48-0.52). However, the mortality rates were also significantly attenuated among those who had a failed AV fistula attempt and dialyzed with a catheter (43 percent in total) when compared with the catheter-only group (HR 0.66, 95% CI 0.64-0.68) [34]. The authors concluded that patient factors likely explain at least two-thirds of the observed difference in mortality in patients treated with an AV fistula.
●A limited number of randomized trials are available comparing the different types of AV access. These include:
•Brachiobasilic fistula versus forearm loop graft — A multicenter study randomly assigned 105 patients with failed AV fistulas or inadequate vessels for radiocephalic or brachiocephalic fistulas to either a brachiobasilic fistula or loop forearm AV graft [35]. Fifty-two percent of patients in the brachiobasilic group and 15 percent of the AV graft group had previously failed an AV fistula. A radial artery and/or cephalic vein diameter of less than 2 mm at the wrist and less than 3 mm at the elbow was defined as unsuitable for the creation of a radiocephalic fistula or brachiocephalic fistula. Compared with the AV graft group, the brachiobasilic group had significantly higher primary patency (46 versus 22 percent) and primary assisted patency (87 versus 71 percent) at one year. Another small trial randomly assigned 57 patients to creation of a brachiobasilic fistula or an AV graft using a collagen-polyester composite material [36]. While patients in the brachiobasilic fistula group had a longer time to cannulation (43 versus 27 days), they had a higher primary patency at one year (52 versus 32 percent), in part because of a lower risk of thrombosis (12 versus 31 episodes).
•Distal AV fistula versus forearm loop graft — A trial that randomly assigned 182 patients with less-than-ideal vessels for radiocephalic fistulas (radial artery between 1 and 2 mm and/or a cephalic vein of 1.6 mm or less) to either an attempt at a radiocephalic fistula or a forearm loop graft found that the AV graft group had higher primary (48 versus 33 percent) and secondary (79 versus 52 percent) patency rates at one year [37].
These observations provided a fresh and critical look at the assumptions that underpinned the promotion of AV fistulas and further contributed to equipoise around this issue. More randomized comparisons of different forms of access are needed. For example, a pilot randomized trial of AV fistula creation in patients who start dialysis with a central venous catheter is underway in Canada to address the feasibility of answering this question in a larger trial (Clinicaltrials.gov identifier: NCT02675569) [38]. In the Netherlands, a randomized trial comparing AV grafts or central venous catheters with AV fistulas is underway [39].
The updated KDOQI Clinical Practice Guideline for Vascular Access: 2019 Update has adopted a patient-centered approach, acknowledging their recommendations are based on expert opinion given the lack of high-quality evidence [26].
●KDOQI considers it reasonable to have an AV access (AV fistula or AV graft) in a patient requiring hemodialysis, when consistent with their ESKD Life-Plan and overall goals of care. (See 'AV fistula appropriateness' below and 'AV graft appropriateness' below.)
●KDOQI considers it reasonable in certain clinical circumstances to use tunneled central venous catheters for short- or long-term access. (See 'Catheter appropriateness' below.)
In addition to the recognition of the importance of patient preference, the guidelines acknowledge the evidence to support the lower risk of bacteremia and bacteremia-related hospitalization in those treated with AV fistulas is of low quality. They also state that there is inadequate evidence to claim AV fistula use results in a lower risk of overall infection, hospitalization, or mortality with AV fistula use – a major departure from prior guidelines.
Preservation of veins — Preservation of peripheral veins and the venous circuit back to the heart is an important component of vascular access planning [40]. It is important to avoid iatrogenic trauma to the venous circulation due to phlebotomy or intravenous access in patients who are at risk for developing end-stage kidney disease or who are already receiving renal replacement therapy of any type. Most experts agree that education regarding vein preservation should begin in individuals with stage 4 or 5 chronic kidney disease and strategies should be implemented to avoid unnecessary trauma to the venous circulation [27,41].
Central venous access should be via a tunneled, internal jugular catheter, while subclavian catheters and peripherally inserted central catheters (PICCs) should be avoided, particularly in the nondominant arm, due to the risk of central venous stenosis and thrombosis. Venous access and phlebotomy should be avoided in the veins of the nondominant arm except in the dorsum of the hand where practical. In patients with pacemakers or previous axillary node dissections, efforts to protect the contralateral arm should be taken. (See "Central venous access: Device and site selection in adults", section on 'General patient considerations'.)
Initial access — A rational strategy for initial (incident) access selection for the individual patient should take into account not only guideline recommendations and local performance targets but the likelihood of success, the expected benefits of one approach versus another, and patient preferences [1,2]. Whether an AV fistula is the best initial access for all patients remains debated. (See 'General comparison' above and 'Patient-centered approach' above.)
All predialysis patients with an expected start of hemodialysis within one year and patients who have initiated hemodialysis with a catheter should be evaluated to determine eligibility for AV access creation [27,42]. Exceptions include patients with limited life expectancy (eg, metastatic cancer or severe heart failure) or patients with a very short expected duration of hemodialysis (eg, pending living-related transplant). (See "Overview of the management of chronic kidney disease in adults", section on 'Preparation for and initiation of kidney replacement therapy' and "Dialysis modality and patient outcome".)
The duration of hemodialysis catheter use should be minimized to avoid complications, particularly central vein stenosis, which can prevent future AV access success. Patients using catheters should be informed about the potential risks of continued use of their catheter. Those without complications may be reluctant to change their access, but these patients should be approached again if they have catheter complications. Some patients may not consent to AV access creation in spite of being informed of the benefits of AV access creation and the risk of hemodialysis catheter use.
AV fistula appropriateness — As a first step, the anatomic and clinical appropriateness of an AV fistula needs to be determined. The anatomic evaluation includes physical examination and may include vascular mapping, typically using ultrasound, to measure the characteristics (eg, diameter, depth) of the available vessels and screen for stenosis or thrombosis. The KDOQI Clinical Practice Guideline for Vascular Access: 2019 Update recommends selective preoperative ultrasound in patients at high risk for AV access failure [26]. While there is no minimum vessel diameter, arteries and veins less than 2 mm should undergo careful evaluation for feasibility and quality prior to creating an AV fistula. (See "Patient evaluation prior to placement of hemodialysis arteriovenous access" and "Arteriovenous fistula creation for hemodialysis and its complications", section on 'Evaluation and planning'.)
Multiple studies have demonstrated risk factors for AV fistula failure, including the use of predictive risk scores [43]. In a study that applied RAND/UCLA appropriateness methodology to 3816 AV fistula and AV graft scenarios, younger age, larger outflow vein diameter, normal or obese body mass index (versus morbidly obese), larger inflow artery diameter, and higher patient functional status were associated with appropriateness of AV fistula creation by a panel of vascular access experts [1,2]. (See "Risk factors for hemodialysis arteriovenous fistula failure".)
AV graft appropriateness — If the expected duration of dialysis is less than two years, and an AV fistula is not possible, then an AV graft should be considered. Early-use AV grafts should be considered to expedite catheter removal as this may decrease catheter-related complications [26,44]. (See "Patient evaluation prior to placement of hemodialysis arteriovenous access" and "Arteriovenous graft creation for hemodialysis and its complications", section on 'Evaluation and planning'.)
In a review of over 66,000 dialysis-dependent patients 66 years or older, the incidence of repeat AV fistula/graft creation and tunneled catheter placement was significantly lower in the first 12 months after index AV graft creation compared with AV fistulas (33.7 versus 44.4 percent) [19]. However, AV fistulas were associated with significantly reduced mortality compared with AV grafts (28.2 versus 29.9 percent).
In the RAND/UCLA study, factors associated with appropriateness for an AV graft included older age and smaller vein size [1,2]. There was no association between sex, diabetes, coronary artery disease, body mass index, or functional status and appropriateness of either a forearm loop graft or upper arm graft.
Catheter appropriateness — Some patients cannot achieve AV access and may need to be managed with a central catheter either in the short term or long term. (See "Central venous catheters for acute and chronic hemodialysis access and their management".)
Appropriate use of a hemodialysis catheter in the short or long term include [26]:
●Short-term duration:
•AV fistula or AV graft created, but not ready for use, and dialysis is required.
•Acute transplant rejection or other complications requiring dialysis.
•Peritoneal dialysis patient with complications that requires time-limited peritoneal rest or resolution of complication (eg, exit site leak).
•Patient has a living donor transplant confirmed with an operation date soon (eg, <90 days) but requires dialysis.
•AV fistula or AV graft complication such as major infiltration injury or cellulitis that results in temporary nonuse until problem is resolved.
●Long-term or indefinite duration:
•Multiple prior failed AV accesses with no available options (see anatomic restrictions below).
•Valid patient preference, whereby use of an AV access would severely limit quality of life or achievement of life goals and after the patient has been properly informed of patient-specific risks and benefits of other potential and reasonable access options for that patient (if available).
•Limited life expectancy.
•Absence of AV access creation options due to a combination of inflow artery and outflow vein problems (eg, severe arterial occlusive disease, noncorrectable central venous outflow occlusion) or in those with prohibitively diminutive vessels.
•Special medical circumstances.
Access maintenance — Proper routine care and maintenance of the access is important to minimizing injury that can lead to dysfunction and thrombosis. This includes the following measures, which are discussed in more detail separately. (See "Overview of hemodialysis arteriovenous fistula maintenance and thrombosis prevention" and "Overview of hemodialysis arteriovenous graft maintenance and thrombosis prevention".)
●Sterile precautions when accessing
●Proper cannulation and decannulation
●Proper care and routine monitoring by the patient at home
●Monitoring clearance rates and access pressures during hemodialysis to identify access dysfunction and intervening on stenoses prior to access thrombosis
Similarly, proper care and maintenance of hemodialysis catheters will reduce the risk for complications, such as infection, catheter thrombosis, and catheter-related thoracic central vein obstruction. (See "Malfunction of chronic hemodialysis catheters" and "Central vein obstruction associated with upper extremity hemodialysis access" and "Central venous catheters for acute and chronic hemodialysis access and their management", section on 'Routine care and access for hemodialysis'.)
Access following failed AV fistula or graft — For patients who develop AV access dysfunction, the individualized ESKD Life-Plan should include plans to salvage the access and if attempts to salvage the access are not successful, plans for future AV access. The vascular evaluation and mapping for determining the appropriateness of a contingency or successive AV access is similar to that undertaken for initial AV access creation [26]. (See "Primary failure of the hemodialysis arteriovenous fistula" and "Failure of the mature hemodialysis arteriovenous fistula" and "Hemodialysis arteriovenous graft dysfunction and failure" and "Hemodialysis access following a failed arteriovenous access".)
Some patients will have exhausted options for creation of a secondary AV access and will necessarily require a hemodialysis catheter. (See 'Catheter appropriateness' above.)
SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Dialysis".)
INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5th to 6th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10th to 12th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.
Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)
●Basics topics (see "Patient education: Preparing for hemodialysis (The Basics)" and "Patient education: Hemodialysis (The Basics)")
SUMMARY AND RECOMMENDATIONS
●The three principal forms of chronic hemodialysis vascular access are arteriovenous (AV) fistulas, AV grafts, and hemodialysis catheters placed into a central vein. AV fistulas and AV grafts are deliberate connections between a native artery and vein. Each of these options has advantages and disadvantages. (See 'Chronic hemodialysis access' above.)
●Care decisions surrounding hemodialysis access are often complex and should be individualized to promote patient-centered care using an interdisciplinary team composed of experienced nurses, nephrologists, radiologists, and vascular surgeons. (See 'Strategy for lifelong hemodialysis access' above.)
●A lifelong access strategy in patients with chronic kidney disease begins with preserving veins for potential future access; carefully evaluating patients for initial AV access if hemodialysis is selected for renal replacement therapy; properly accessing, maintaining, and monitoring the access; and timely management of problems if they arise. (See 'Strategy for lifelong hemodialysis access' above.)
●For patients without contraindications to AV access, AV fistulas have been strongly promoted in the past; however, under certain circumstances, AV graft placement may be equally appropriate, or more appropriate for initial AV access. For some patients, hemodialysis catheters may be an appropriate hemodialysis access in the short or long term. (See 'Initial access' above.)
●The justification for a "fistula first" approach has been a consistent association of AV fistula use with lower morbidity and mortality in observational studies. It is important to recognize the high risk of bias in these studies. It is not clear whether the better outcomes observed in patients using AV fistulas for initial vascular access were due to the choice of vascular access or that patients selected for AV fistulas were healthier and had a better prognosis. Later large observational studies support this concept, but ideally a randomized comparison of different types of hemodialysis access is needed to better inform decision making in clinical practice. (See 'Patient-centered approach' above.)
آیا می خواهید مدیلیب را به صفحه اصلی خود اضافه کنید؟
