Version July 2025
INTRODUCTION —
The evaluation of patients with end-stage kidney disease (ESKD) in preparation for the placement of hemodialysis access is extremely important. Proper patient selection enhances the opportunity to place the most appropriate access for the individual patient. This evaluation should be detailed and complete. (See "Patient evaluation prior to placement of hemodialysis arteriovenous access".)
Each predialysis and dialysis patient should have an individualized ESKD Life Plan [1], which should start in the predialysis period if possible, with the goal of maximizing the ESKD dialysis modality choices and utilization for a specific patient's foreseeable lifespan. In developing this plan, risk factors that potentially adversely affect the success of dialysis access must be taken into consideration.
Many patients have more than one risk factor because they have multiple comorbidities. The dialysis patient population is among the sickest, with a symptom burden comparable to patients with cancer [2,3]. Older patients represent the most rapidly growing group of dialysis patients, and approximately one-half of ESKD patients over 75 years of age have three or more comorbidities [4].
The risk factors associated with failure of hemodialysis AV fistula maturation and failure of a mature AV fistula are reviewed. Although this discussion is directed primarily toward factors that create a risk for failure of arteriovenous (AV) fistula development, some of these factors also represent a risk to the patient's life and well-being (eg, potential for limb loss). The choice of hemodialysis AV access and placement and care of the AV fistula are reviewed separately. (See "Arteriovenous fistula creation for hemodialysis and its complications" and "Overview of hemodialysis arteriovenous fistula maintenance and thrombosis prevention" and "Approach to the adult patient needing vascular access for chronic hemodialysis".)
The definitions used for hemodialysis access time points used in this topic (eg, primary patency, assisted primary patency, postintervention patency) are provided in the figure (figure 1 and table 1).
USE OF RISK FACTORS —
Although risk factors are important, risk stratification schemes based on demographic and clinical parameters fail to accurately identify individuals in whom arteriovenous (AV) fistula placement is futile. The identification of a high-risk patient simply dictates the need for more intensive, individualized evaluation [5]. The most important determinant in the success of an AV fistula is the quality of the available vessels (see 'Hemodynamic' below). Individualization based on preprocedural vascular mapping is critical. No patient with end-stage kidney disease (ESKD) should be excluded from consideration for an AV fistula without vascular mapping and evaluation by an experienced hemodialysis access vascular surgeon. (See "Patient evaluation prior to placement of hemodialysis arteriovenous access".)
While the goal of patient evaluation prior to access placement is to facilitate the placement of an AV fistula, failure of AV fistula maturation remains a major problem with serious clinical consequences, not least of which is prolonging the period of catheter dependency. Thus, patients with a low likelihood of AV fistula maturation based on an individualized evaluation might be better served by the placement of an AV graft. (See "Approach to the adult patient needing vascular access for chronic hemodialysis", section on 'Strategy for lifelong hemodialysis access'.)
RISK FACTORS —
The risk of poor arteriovenous (AV) fistula maturation or subsequent AV fistula failure can be related to hemodynamic factors, patient-related demographic or clinical factors, and other technical issues. Among these, hemodynamic factors are the most important. Demographic and clinical risks are generally realized only when they affect hemodynamics.
●Hemodynamic – Vein size, feeding artery size, blood flow (see 'Hemodynamic' below)
●Demographic – Patient age, sex, race/ethnicity (see 'Demographic' below)
●Clinical – The presence of cardiac disease, peripheral arterial disease, pulmonary hypertension, diabetes mellitus, and obesity (see 'Clinical comorbidities' below)
●Technical – Training and experience of the surgeon, fistula creation, care, and use of the AV fistula (see 'Technical' below)
Hemodynamic — The value of vascular mapping in assessing hemodynamic parameters has been well documented in the literature. (See "Patient evaluation prior to placement of hemodialysis arteriovenous access" and "Arteriovenous fistula creation for hemodialysis and its complications".)
Patients with inadequate vessel size or quality may not be candidates for an AV fistula, at least initially. In these cases, the creation of an AV access in the forearm using graft material may be the best option. The purpose is twofold. The AV graft will provide useable dialysis access, and the veins in the upper arm may develop over time, such that a secondary AV fistula may be possible if the AV graft becomes problematic [6]. (See "Hemodialysis access following a failed arteriovenous access".)
Demographic — Demographic factors include age, sex, and race/ethnicity.
Age-related — Age is an increasingly important factor to consider when planning hemodialysis vascular access. Older individuals are the fastest-growing group with end-stage kidney disease (ESKD). Given the increasing number of older patients with kidney failure, it is crucial to take into account the effects of aging, comorbidities, and frailty, as well as the advantages and drawbacks of various management options for chronic kidney disease (CKD) in the older adult population [7,8].
Older age is a risk factor for decreased life expectancy on dialysis, but age alone doesn’t account for the many other factors associated with AV access failure [9-11]. Older age largely acts as a surrogate for an increasing incidence of comorbidities, which appear to have a stronger effect on survival than incremental age alone [12,13]. (See 'Clinical comorbidities' below.)
An issue often overlooked is frailty, which encompasses both physical and psychological components. Frailty increases with age and has been associated with adverse dialysis access outcomes, other adverse health outcomes, and increased mortality [14,15]. For these reasons, vascular access planning must take into consideration the patient's life expectancy balanced with the time required for each type of vascular access to become usable and its expected durability, as well as frailty [9,16-19].
Among older patients, AV fistulas are reported to require a longer maturation time and more interventions to assist maturation compared with younger age patients [20]. Nevertheless, the creation of an AV fistula is an appropriate choice for any patient with a life expectancy of one year or more who has good vessels (based on vascular mapping) and without anticipated interventions to achieve access function [21]. Data suggest that once an AV fistula is successfully created in such a patient, the patency appears to be comparable with that of younger age groups for at least the first 18 months after creation [22-26]. Although an AV fistula offers advantages related to patency, infection, mortality, and hospitalization, these benefits do not accrue immediately. Thus, patients with a life expectancy of less than 18 months do not experience these benefits. For patients with poor vessels or limited life expectancy, an AV graft would be a better alternative. (See "Approach to the adult patient needing vascular access for chronic hemodialysis" and "Arteriovenous fistula creation for hemodialysis and its complications".)
An integral part of the patient's ESKD Life Plan is the adoption of an anatomic progression in access planning that preserves more proximal vessels. Classically, the order preference to accomplish this goal is to start distally, if possible, with a radial-cephalic AV fistula. However, studies indicate that this approach may not be appropriate for older adults in whom an upper arm fistula may be more successful [27-29]. In a meta-analysis that compared forearm versus upper arm AV fistulas in patients 75 years or older, the 12-month primary and secondary failure rates were higher for forearm AV fistulas compared with proximal upper arm AV fistulas (OR 2.14, 95% CI 1.53-2.97 and OR 1.76, 95% CI 1.12-2.78, respectively) [29]. (See "Approach to the adult patient needing vascular access for chronic hemodialysis" and "Arteriovenous fistula creation for hemodialysis and its complications".)
Sex-related — As with older age, sex also presents several unique features related to dialysis and vascular access.
Males have a higher level of kidney function compared with females at the same level of serum creatinine as a result of greater muscle mass and creatinine generation. This is important to recognize because referrals for vascular access at a fixed level of serum creatinine would systematically refer females with more advanced diseases [30].
Multiple studies have shown differences between males and females in AV fistula creation, maturation, and use [31-35]. Although males tend to have more comorbidities at the initiation of dialysis [36], more females initiate dialysis with a catheter [35-38]. Compared with males, fewer females undergo AV fistula creation attempts, are less likely to use an AV fistula on dialysis [35,39,40], and once created, an AV fistula is less likely to mature even with preoperative vessel mapping [31], regardless of type [32,35].
In a Canadian study involving 1446 males and 929 females [36], females were less likely to receive an AV fistula attempt at six and 12 months after dialysis initiation, resulting in prolonged catheter use; males were almost three times more likely to achieve catheter-free dialysis using an AV fistula. Even though procedures performed to facilitate the successful use of an AV fistula were equal between males and females, females were less likely to achieve AV fistula use. In this study, females were older at the initiation of dialysis, and males tended to have more comorbidities. The most common AV fistula created in females was a radial-cephalic, and in males, it was a brachial-cephalic AV fistula.
In a systematic review that included 53 studies, females had lower AV fistula maturation rates, decreased rates of primary, primary assisted, and secondary patency; required more procedures per patient to achieve maturation and maintain AV fistula patency; were more likely to receive dialysis via an arteriovenous graft or central venous catheter; and required a longer time and potentially more assistive invasive interventions to achieve a mature fistula.
The 2023 United States Renal Data System (USRDS) report (based on 2021 and 2020 data) [41] supports these findings.
●At the initiation of dialysis, 13 percent of males were using an AV fistula compared with 11 percent of females.
●The increase in AV fistula use at 3, 6, and 12 months for males versus females was 7.1 versus 3.9 percent, 18.5 versus 12.5 percent, and 27.1 versus 20.5 percent, respectively.
●Among patients initiating hemodialysis with a catheter, the percentage of males versus females dialyzing with an AV fistula at 3, 6, and 12 months was 9.3 versus 6.3 percent, 23.6 versus 16.7 percent, and 35.2 versus 27.1 percent, respectively.
●AV fistula use among prevalent patients was 65.9 percent for males versus 53.5 percent for females.
While patency was better for males than females, the differences were rather small. The duration of primary, assisted primary, and cumulative patency at six months for males versus females was 68.1 versus 66 percent, 89.4 versus 88.3 percent, and 98.4 versus 98 percent, respectively. The same variables at 12 months were 66.3 versus 57.8 percent, 85.7 versus 84.8 percent, and 97.8 versus 97.4 percent, respectively.
The reasons for these sex-related differences are not clear. Several studies based on vascular mapping found no significant sex-related difference in vein size [42,43]. However, definite gender differences in arterial size and physiology have been documented. The brachial artery is significantly smaller in young adult females than in males [44]. However, in one study, although arteries used for AV fistula construction were smaller in females in both forearm and upper arm access placements, in a comparison between successful and unsuccessful AV fistulas, no significant size differences were noted in either the forearm or upper arm placements [43]. Multiple studies have demonstrated that vascular compliance decreases with age in both males and females; however, the magnitude of the decrease is greater in females [45,46]. In addition, sex-related differences in basal vascular tone, basal blood flow, flow-mediated vasodilation, and shear stress have also been documented [47]. The role, if any, that these factors might play in the etiology of the sex-related differences in dialysis access is not known.
Race/ethnicity-related — Although not consistently reported, race has been listed as a risk factor for failure of AV fistula maturation, and racial/ethnic differences have been documented in AV fistula use in prevalent dialysis patients [5,48-52]. In a study involving 195,756 adult patients initiating outpatient hemodialysis, the likelihood of Black patients beginning dialysis therapy using an AV fistula was 16 percent lower compared with White and Hispanic patients [48].
A retrospective analysis of all patients in the USRDS data system who initiated dialysis between January 1, 2007, and December 31, 2014, was performed [33]. This study, which included 285,781 AV fistula patients with a mean follow-up of 26.1 months, reported no statistically significant difference between AV fistula maturation in White (77 percent), Black (76.3 percent), and Hispanic (77.8 percent) patients. AV fistula maturation occurred within a slightly shorter period in Hispanic (78 days) and Black (81 days) patients compared with White (88 days) patients. The cumulative patency at five years was significantly shorter for Black patients (compared with White and Hispanic patients [43 versus 47 and 52 percent, respectively]).
According to the 2023 USRDS report (2021 data) for dialysis access in prevalent patients, Black patients were less likely to use an AV fistula than other racial groups (54.2 versus ≥61.5 percent) [41]. They were also less likely than most other major racial groups to start dialysis with an AV fistula (10.4 versus 13.5, 10.4, and 16.0 for White, Hispanic, and Asian American patients, respectively) and less likely to start dialysis with a catheter and a maturing AV fistula (9.6 versus 10.2, 10.8 and 10.8 for percent White, Hispanic and Asian Americans, respectively). However, cumulative AV fistula patency at 24 months was similar across groups (97.3, 96.4, 97.1, and 96.5 percent for White, Black, Hispanic, and Asian Americans).
The reasons for these racial differences are not totally clear. While a genetic difference between different racial/ethnic groups cannot be totally discarded, there are definite differences in comorbidities between the groups [25,53-56]. These factors have the potential to affect the development of ESKD and the creation of an AV fistula for dialysis.
There is an increased incidence of both obesity and diabetes in Black individuals with ESKD. Analysis of combined Centers for Disease Control and Prevention data from the years 2015 through 2017 found the incidence of obesity, defined by body mass index ≥30 kg/m2, in Black (not Hispanic) adults was 38.4 percent in contrast to 32.6 percent in Hispanic and 28.6 percent in White (not Hispanic) patients [57]. These factors can adversely affect AV fistula creation but have a positive effect on patient longevity due to the "obesity paradox" [58]. While 60 percent of the ESKD population has diabetes, the age-adjusted incidence of ESKD related to diabetes for 2021 was 2.9 times higher in the Black compared with a White population (326.5 per million versus 111.5) [41].
Clinical comorbidities — Clinical risk factors for AV fistula failure include the presence of cardiac disease, pulmonary disease, peripheral arterial disease, diabetes, and obesity.
Cardiac disease — Cardiovascular disease (CVD) is an important comorbidity among patients with CKD. According to the 2023 USRDS report, 26 percent of patients have heart failure, 11 percent have atherosclerotic heart disease, and 20 percent have other types of cardiac disease [41]. Cardiovascular risk of patients with CKD is multifactorial and attributable to classical risk factors and comorbidities, including hypertension, dyslipidemia, and diabetes, often present in this population in conjunction with less-well-defined, kidney-specific risk modifiers related to disturbed renal hemostasis, calcium-phosphate metabolism, and accumulation of uremic toxins [59]. In addition, CVD and CKD share risk factors such as diabetes and hypertension.
CKD is associated with changes that can increase the risk of developing CVD, such as abnormalities of mineral metabolism, anemia, volume overload, and CKD-associated vascular changes. CVD can also increase the risk of CKD [48]. In addition, all forms of CVD have an increased incidence in CKD patients. This close relationship should be considered in dialysis access planning. Classification during the predialysis period according to the severity of cardiac symptoms in one of four categories (New York Heart Association Functional class I to IV) can help guide the selection of the most appropriate hemodialysis access [60]. (See "Evaluation and management of heart failure caused by hemodialysis arteriovenous access".)
Multiple studies have shown that while dialysis access is a necessary "lifeline," it can exert an adverse effect on the heart. AV fistula maturation is a process that involves the entire cardiovascular system through a flow-mediated remodeling of arterial inflow and venous outflow, as well as the cardiac muscle itself. The heart is a critical part of the dialysis access circuit, providing the driving force for blood flow necessary to meet the demands of the dialysis access. The creation of an AV fistula produces a hyperdynamic state that increases cardiac workload (volume-loaded state) and exerts significant effects on cardiac systolic and diastolic performance. Many of the early cardiac changes are physiological and adaptive; however, some are maladaptive and deleterious to cardiac function and can lead to increased cardiac strain and poor subendocardial perfusion [61].
For patients with relatively normal cardiac function, the creation of an AV fistula should not be expected to have adverse effects. Some reports have noted an improvement in cardiovascular function with the creation of AV dialysis access [62]. However, poor cardiac function adversely affects blood flow to the developing AV fistula. In addition, by increasing the demand for cardiac output, the AV fistula can adversely affect the heart.
ESKD patients with decreased cardiac reserve are at risk for developing heart failure after AV access construction, while those with a history of heart failure are at risk for worsening their condition. The coexistence of heart failure and CKD doubles the risk of death [63]. More than 50 percent of hemodialysis patients die because of a cardiovascular event frequently associated with heart failure, most with functional AV fistulas [20,64,65]. (See "Management of heart failure in patients on dialysis".)
The deleterious effect of an AV fistula on the heart is directly proportional to access blood flow [66]. Since the flow rate is generally higher with a brachial artery-based AV fistula compared with a radial artery-based AV access, the increase in cardiac output will be proportionately more. In a prospective study involving 96 hemodialysis patients, 31 patients with an upper-arm AV fistula had a significantly higher mean flow rate, cardiac output, and flow rate to cardiac output ratio compared with 65 patients with a lower-arm AV fistula [67]. This difference was evident even in the early maturation period of AV fistula creation. In an observational study of 562 predialysis patients, the location of the AV fistula was closely related to the incidence of heart failure (40 percent in brachial-cephalic versus 8 percent in radial-cephalic AV fistula) [61]. This suggests that in a patient with decreased cardiac function, if an AV fistula is created, radial artery-based access with a lower flow rate would be desirable.
Peripheral arterial disease — To achieve a functional AV fistula, the feeding brachial artery must increase baseline blood flow 10- to 20-fold to deliver the required blood volume for the fistula, as well as to supply distal tissues [68]. To do this, the artery must increase diameter sufficiently by remodeling to accommodate the increased flow [69]. Peripheral arterial disease interferes with this process. In one study involving 784 incident hemodialysis patients, a history of peripheral artery disease was associated with a 24 percent higher risk of AV fistula failure [70].
Peripheral arterial disease changes in the vessel wall are characterized by intimal hyperplasia and calcification. At a histologic level, the presence of calcium deposits within the vessel wall of radial and brachial arteries in patients with CKD has been correlated with increased arterial stiffness and decreased elasticity [71].
In a study involving 59 patients in whom a radial-cephalic AV fistula was created, surgically obtained arterial specimens were examined for intimal hyperplasia, which was found in 45 cases [72]. Patients with intimal hyperplasia were older and had a higher incidence of diabetes. A strong correlation was seen between AV fistula failure and intimal hyperplasia. In another study involving 72 patients with diabetes patients, macrocalcification (Mönckeberg type) in the vessel wall (determined radiologically) correlated with decreased long-term AV fistula patency [73]. It is of interest that in another publication, microcalcification (determined histologically) did not affect AV fistula maturation [74].
Tests directed toward the detection of feeding artery pathology have been advocated (eg, resistive index, assessment of arterial stiffness and elasticity, hyperemic response) [71]. A number of studies have reported a positive correlation between poor results in these tests and AV fistula failure [75-80]. As an example, in a small study of patients undergoing AV fistula placement, the average radial artery elasticity index (ie, less stiffness) was higher in the group that developed a mature AV fistula compared with the group in whom the AV fistula failed; however, the brachial artery elasticity index was not significantly different in the success and failure groups.
Pulmonary hypertension — Pulmonary hypertension is also an important comorbidity in those with CKD. Its presence can materially affect the life expectancy of the dialysis patient and influence dialysis access choices. Ultimately, pulmonary hypertension affects 21 to 41 percent of patients with CKD and up to 60 percent of patients treated with hemodialysis [63,81-83]. (See "Pulmonary hypertension in patients with end-stage kidney disease".)
Pulmonary hypertension is associated with an increased risk of cardiovascular events and overall mortality [84-86]. Although the highest level occurs in dialysis patients, an increased incidence has been reported prior to the initiation of dialysis. In one study of 211 patients, an incidence of 21.6, 24.1, and 31.7 percent was reported in patients with CKD stages 3, 4, and 5, respectively, not on dialysis [87].
Although not directly related to kidney disease, chronic obstructive pulmonary disease (COPD) is a significant cause of mortality in the population at large; this is no less so for patients with ESKD. In 2013, the overall incidence in the United States was 6.4 percent [88]. From 2000 to 2010, the prevalence of COPD in the patient age group 60 to 79 years (the fastest-growing ESKD age group) was 13.5 percent [89,90].
Diabetes mellitus — Although diabetes mellitus is generally listed as a risk factor for AV fistula failure, the patient with diabetes state does not exert a direct adverse effect on the success of the access; however, the comorbidities associated with diabetes do have a definite effect. As was the case with advanced age, diabetes serves as a surrogate for other comorbidities. Individuals with diabetes have a high risk of developing cardiovascular disease, including peripheral arterial disease [91]. The relationship is even greater in patients with CKD [25]. There is also an interplay between other clinical and demographic risk factors. (See 'Race/ethnicity-related' above.)
Since it is not diabetes as such but the associated burden of comorbidities that exerts the effect, pre-access clinical and hemodynamic evaluation can make a marked difference in achieving success with AV fistula creation. While some reports indicate a negative effect of diabetes on AV fistula success [92-94], most investigators have reported that diabetes is not significantly associated with primary AV fistula failure and that the success rate of a forearm AV fistula is comparable in patients with and without diabetes [74,95-98].
Obesity — Two issues are of importance when considering the creation of an AV fistula in a patient who is obese. First, obesity is a major risk factor for the development of type 2 diabetes. Therefore, these patients frequently present with the same issues as discussed for the patient with diabetes (see 'Diabetes mellitus' above). The second is the technical issue related to the depth of the vessels used to create the fistula. An added consideration is the obesity paradox (ie, higher body mass index [BMI] is paradoxically associated with better survival among kidney failure patients) [58,99-102]. This, in addition to the fact that patients with severe obesity may be excluded from transplant consideration, means that their accesses must last longer than those of other patients.
When presented with a patient with obesity, there is no reason to avoid the creation of an AV fistula, but evaluation of hemodynamic factors by vascular mapping becomes particularly important. A retrospective cohort analysis was performed using the USRDS Dialysis Morbidity and Mortality Wave II data set to evaluate the relationships between obesity and vascular access outcomes [103]. Obesity was associated only with poorer AV fistula maturity at the highest BMI quartile (≥35 kg/m2) and not with increased AV fistula revision rates or failure. However, although the likelihood of fistula placement and primary patency rates were similar across groups, secondary patency was significantly lower in patients with obesity [104]. This means that while the initial placement and primary use of the fistula might be similar between patients who are and who are not obese, the long-term success and durability of the fistula are often lower in obese individuals. It has been suggested that the decreased secondary patency in these patients could be due to soft tissue compression of the venous outflow of the upper extremity in the adducted position [105].
In addition, a technical problem can occur in patients with obesity related to the depth of the veins, which tend to be deep due to the adiposity of the extremity, particularly in the upper arm. If the AV fistula is located too deeply from the skin surface, a procedure can be performed to elevate the fistula, which has been reported to be very successful [106]. Alternatively, lipectomy or liposuction has also been proposed as a means to minimize the depth of AV fistulas in obese arms [107-110].
Technical
Surgical training and experience — The training and experience of the surgeon available to create AV access varies and can affect the success of AV fistula creation [111-117].
In a study designed to investigate whether the intensity of surgical training influenced the type of vascular access placed and AV fistula survival, prospective data from 12 countries in the Dialysis Outcomes and Practice Patterns Study (DOPPS) were analyzed [115]. Significant predictors of AV fistula versus AV graft placement included the number of AV fistulas placed and the degree of emphasis on vascular access creation during training. In the United States, surgeons in training created fewer AV fistulas compared with those in other countries (mean 16 versus 39 [from 426 in other countries]). They noted less emphasis on vascular access placement compared with surgeons elsewhere. The risk of primary AV fistula failure was 34 percent lower when placed by surgeons who created >25 (compared with <25) AV fistulas during training. However, no difference was noted between categories of 25 to 75 or >75 AV fistulas created during training.
Once out of training, surgeons' experience continues to vary in the number of AV fistulas they place, which in turn can impact the outcome of the procedure. As an example, in a United States study, the number of AV fistula or grafts placed by nearly 5000 surgeons ranged from 10 to 681 over two years [117]. A successful outcome (ie, mature fistula) was more likely at six months follow-up for surgeons who performed >85 AV fistula placements compared with those who performed fewer than 13 (odds ratio 1.5, 95% CI 1.4-1.6).
Creating the AV fistula — Related to training and experience is the appropriate choice of vessel and conduct of the procedure used to create the hemodialysis AV fistula. Perioperative factors that may lead to immediate issues following AV fistula creation are reviewed separately. (See "Arteriovenous fistula creation for hemodialysis and its complications" and "Primary failure of the hemodialysis arteriovenous fistula".)
Care and maintenance of the AV fistula — Factors associated with the use, care, and maintenance of the AV fistula may contribute to AV fistula failure. These are reviewed separately. (See "Overview of hemodialysis arteriovenous fistula maintenance and thrombosis prevention" and "Failure of the mature hemodialysis arteriovenous fistula".)
MULTIPLE RISK FACTORS —
As can be seen, there are a variety of risk factors that affect the success of an arteriovenous (AV) fistula. Most patients have more than one risk factor, and the burden increases with age. It is difficult for the clinician to determine the relative importance of these potential risk factors and to assess the effect of combinations when assessing the likelihood of achieving a functional AV fistula in the individual patient. While evaluating risk factors is important, risk stratification schemes have failed to accurately identify individuals in whom AV fistula placement is futile. While comorbid conditions affecting vascular access success become increasingly more common with age, they are not necessarily present [118]. Further, although potential demographic and clinical factors may be relevant, the most important determinant is the quality of the available vessels. Thus, no patient with end-stage kidney disease should be excluded from consideration for an AV fistula without vascular mapping and evaluation by an experienced hemodialysis vascular access surgeon. Decisions should be based on the individual patient status as determined by the clinical comorbidities that are present.
A study was conducted toward the development of an algorithm to be used in assessing individual patients having a combination of risk factors [5]. The goals of the study were to identify clinical characteristics that predicted failure of AV fistula maturation and to develop and validate a risk equation using these characteristics to stratify patients according to their risk. A clinical prediction rule was used to assign a prediction score ranging from 0 to 10.5. These scores were then used to define four risk categories: low risk (score <2), moderate risk (score 2 to 3), high risk (score 3 to 7), and very high risk (score >7). The algorithm was externally validated using 445 patients receiving a new AV fistula derived from five large dialysis centers. The four defined categories predicted the risk of failure to mature as 24, 34, 50, and 69 percent, respectively. The authors suggested that this scoring system could be used to guide the aggressiveness with which the individual patient is evaluated prior to dialysis access placement and postoperatively to detect failure maturation. As an example, in low-risk patients, vascular mapping by physical examination may only be possible with routine postoperative monitoring. In contrast, the patient in the high-risk category might require angiographic evaluation (both vein and artery) and very close postoperative monitoring, anticipating the need for aggressive intervention to facilitate maturation.
In a later study, 195,756 incident adult dialysis patients with an AV fistula who had been followed for at least six months by nephrologists prior to initiation of dialysis were examined based on the presence of risk factors for AV fistula failure of maturation [119]. The risk factors for AV fistula failure, determined by logistic regression, were substantially different from those predicted by the clinical prediction algorithm above. Based upon a comparison with the low-risk group, the likelihood of AV fistula use was 0.90 (95% CI 0.88-0.93) for the moderate-risk group, 0.80 (95% CI 0.78-0.83) for the high-risk group, and 0.68 (95% CI 0.63-0.73) for the very-high-risk group.
In assessing the importance of risk factors, it is important to realize that these two studies are based on different patient populations [5,119]. The first proposed a scoring system to predict problems with AV fistula maturation. It emphasized the importance of using this data in the presurgical selection and postsurgical management of individual patients [5]. The second study demonstrates the actual prevalence of AV fistula utilization; the results are presumably a reflection of presurgical selection and postsurgical management [119].
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" and "Society guideline links: Hemodialysis vascular access".)
SUMMARY AND RECOMMENDATIONS
●Risk factors and their use – Recognition of risk factors, especially the presence of multiple risk factors, is important in planning arteriovenous (AV) access creation for hemodialysis. However, no patient with end-stage kidney disease should be excluded from consideration for an AV fistula without vascular mapping and evaluation by a dialysis-access-experienced surgeon. Individualization is critically important. (See 'Use of risk factors' above and 'Multiple risk factors' above.)
●Hemodynamic factors – Adverse hemodynamic characteristics (poor-quality vessels) are the most important factors contributing to the failure of AV fistula maturation and subsequent failure of a mature AV fistula. Demographic and clinical factors increase the risk of AV fistula failure primarily only when they affect hemodynamics. Although patients with poor-quality vessels are not ideal candidates for an AV fistula initially, a secondary fistula may be possible after a period of AV graft use if the AV graft becomes problematic. (See 'Hemodynamic' above.)
●Age-related factors – Older age is a risk factor for decreased life expectancy on dialysis; however, age is largely a surrogate for an increasing burden of comorbid conditions (particularly diabetes and cardiovascular disease). The presence of comorbidities more strongly influences survival compared with age alone. (See 'Age-related' above and 'Clinical comorbidities' above.)
●Sex-related factors – Female sex is a risk factor for failure of AV fistula maturation and subsequent failure of the mature AV fistula. The reasons for sex-related differences are not clear. While it has been suggested that females have smaller vessels, diameter differences have not been consistently related to unsuccessful AV fistulas. (See 'Sex-related' above.)
●Race and ethnicity-related factors – Race and ethnicity have been identified as significant risk factors for failure of AV fistula maturation. The reasons for the difference are not totally clear but may be related to differences in comorbidities between the groups. (See 'Race/ethnicity-related' above.)
●Comorbidities – Clinical comorbidities (cardiac disease, peripheral arterial disease, pulmonary disease, diabetes mellitus, obesity) adversely affect the placement and clinical success of AV fistulas. These generally exert their effect by adversely affecting hemodynamics. (See 'Clinical comorbidities' above.)
●Other factors – Other factors that may affect the outcomes of AV fistula creation include the experience of the surgeon and other technical issues in creating, using, and caring for the fistula. (See 'Technical' above.)
