Effects of a More Selective Arteriovenous Fistula Strategy on Vascular Access Outcomes.

SIGNIFICANCE STATEMENT: The optimal choice of vascular access for patients undergoing hemodialysis-arteriovenous fistula (AVF) or arteriovenous graft (AVG)-remains controversial. In a pragmatic observational study of 692 patients, the authors found that among patients who initiated hemodialysis with a central vein catheter (CVC), a strategy that maximized AVF placement resulted in a higher frequency of access procedures and greater access management costs for patients who initially received an AVF than an AVG. A more selective policy that avoided AVF placement if an AVF was predicted to be at high risk of failure resulted in a lower frequency of access procedures and access costs in patients receiving an AVF versus an AVG. These findings suggest that clinicians should be more selective in placing AVFs because this approach improves vascular access outcomes. BACKGROUND: The optimal choice of initial vascular access-arteriovenous fistula (AVF) or graft (AVG)-remains controversial, particularly in patients initiating hemodialysis with a central venous catheter (CVC). METHODS: In a pragmatic observational study of patients who initiated hemodialysis with a CVC and subsequently received an AVF or AVG, we compared a less selective vascular access strategy of maximizing AVF creation (period 1; 408 patients in 2004 through 2012) with a more selective policy of avoiding AVF creation if failure was likely (period 2; 284 patients in 2013 through 2019). Prespecified end points included frequency of vascular access procedures, access management costs, and duration of catheter dependence. We also compared access outcomes in all patients with an initial AVF or AVG in the two periods. RESULTS: An initial AVG placement was significantly more common in period 2 (41%) versus period 1 (28%). Frequency of all access procedures per 100 patient-years was significantly higher in patients with an initial AVF than an AVG in period 1 and lower in period 2. Median annual access management costs were significantly higher among patients with AVF ($10,642) versus patients with AVG ($6810) in period 1 but significantly lower in period 2 ($5481 versus $8253, respectively). Years of catheter dependence per 100 patient-years was three-fold higher in patients with AVF versus patients with AVG in period 1 (23.3 versus 8.1, respectively), but only 30% higher in period 2 (20.8 versus 16.0, respectively). When all patients were aggregated, the median annual access management cost was significantly lower in period 2 ($6757) than in period 1 ($9781). CONCLUSIONS: A more selective approach to AVF placement reduces frequency of vascular access procedures and cost of access management.

The reasons for comparative effectiveness clinical trials of arteriovenous fistula versus graft strategy in older adults on hemodialysis with a catheter.

Clinicians and patients are guided by observational studies to make one of the most consequential decisions for patients with advanced kidney disease: the selection of the "right" hemodialysis vascular access. More than a decade ago, a call for randomized clinical trials was made to equitably compare clinical outcomes between arteriovenous (AV) fistulas (AVFs) and AV grafts (AVGs). Mounting evidence suggests that trade-offs between AVF- and AVGrelated outcomes are context dependent. In this article, we summarize four streams of evidence that collectively underpin the burden of equipoise between the two types of AV access in older adults with comorbidities who are on hemodialysis with a central venous catheter.

Study protocol of a randomized controlled trial of fistula vs. graft arteriovenous vascular access in older adults with end-stage kidney disease on hemodialysis: the AV access trial.

BACKGROUND: Treatment of end-stage kidney disease (ESKD) with hemodialysis requires surgical creation of an arteriovenous (AV) vascular access-fistula (AVF) or graft (AVG)-to avoid (or limit) the use of a central venous catheter (CVC). AVFs have long been considered the first-line vascular access option, with AVGs as second best. Recent studies have suggested that, in older adults, AVGs may be a better strategy than AVFs. Lacking evidence from well-powered randomized clinical trials, integration of these results into clinical decision making is challenging. The main objective of the AV Access Study is to compare, between the two types of AV access, clinical outcomes that are important to patients, physicians, and policy makers. METHODS: This is a prospective, multicenter, randomized controlled trial in adults ≥ 60 years old receiving chronic hemodialysis via a CVC. Eligible participants must have co-existing cardiovascular disease, peripheral arterial disease, and/or diabetes mellitus; and vascular anatomy suitable for placement of either type of AV access. Participants are randomized, in a 1:1 ratio, to a strategy of AVG or AVF creation. An estimated 262 participants will be recruited across 7 healthcare systems, with average follow-up of 2 years. Questionnaires will be administered at baseline and semi-annually. The primary outcome is the rate of CVC-free days per 100 patient-days. The primary safety outcome is the cumulative incidence of vascular access (CVC or AV access)-related severe infections-defined as access infections that lead to hospitalization or death. Secondary outcomes include access-related healthcare costs and patients' experiences with vascular access care between the two treatment groups. DISCUSSION: In the absence of studies using robust and unbiased research methodology to address vascular access care for hemodialysis patients, clinical decisions are limited to inferences from observational studies. The goal of the AV Access Study is to generate evidence to optimize vascular access care, based on objective, age-specific criteria, while incorporating goals of care and patient preference for vascular access type in clinical decision-making. TRIAL REGISTRATION: This study is being conducted in accordance with the tenets of the Helsinki Declaration, and has been approved by the central institutional review board (IRB) of Wake Forest University Health Sciences (approval number: 00069593) and local IRB of each participating clinical center; and was registered on Nov 27, 2020, at ClinicalTrials.gov (NCT04646226).

Ovulation and birth after administration of progesterone trigger-two case reports.

PURPOSE: To determine whether using progesterone as a trigger of a gonadotropin surge will induce ovulation and a competent corpus luteum. METHODS: Patients were administered 5 or 10 mg of progesterone intramuscularly when the leading follicle reached preovulatory size. RESULTS: We demonstrate that progesterone injections result in classical ultrasonographic hallmarks of ovulation about 48 h later and the formation of a corpus luteum competent to support pregnancy. CONCLUSION: Our results support further exploration of using progesterone to trigger a gonadotropin surge in assisted human reproduction.

Early Predictors of Arteriovenous Fistula Maturation: A Novel Perspective on an Enduring Problem.

BACKGROUND: Preoperative ultrasound mapping is routinely used to select vessels meeting minimal threshold diameters for surgical arteriovenous fistula (AVF) creation but fails to improve AVF maturation rates. This suggests a need to reassess the preoperative ultrasound criteria used to optimize AVF maturation. METHODS: We retrospectively identified 300 catheter-dependent patients on hemodialysis with a new AVF created between 2010 and 2016. We then evaluated the associations of preoperative vascular measurements and hemodynamic factors with unassisted AVF maturation (successful use for dialysis without prior intervention) and overall maturation (successful use with or without prior intervention). Multivariable logistic regression was used to identify preoperative factors associated with unassisted and overall AVF maturation. RESULTS: Unassisted AVF maturation associated with preoperative arterial diameter (adjusted odds ratio [aOR], 1.50 per 1-mm increase; 95% confidence interval [95% CI], 1.23 to 1.83), preoperative systolic BP (aOR, 1.16 per 10-mm Hg increase; 95% CI, 1.05 to 1.28), and left ventricular ejection fraction (aOR, 1.07 per 5% increase; 95% CI, 1.01 to 1.13). Overall AVF maturation associated with preoperative arterial diameter (aOR, 1.36 per 1-mm increase; 95% CI, 1.10 to 1.66) and preoperative systolic BP (aOR, 1.17; 95% CI, 1.06 to 1.30). Using receiver operating curves, the combination of preoperative arterial diameter, systolic BP, and left ventricular ejection fraction was fairly predictive of unassisted maturation (area under the curve, 0.69). Patient age, sex, race, diabetes, vascular disease, obesity, and AVF location were not associated with maturation. CONCLUSIONS: Preoperative arterial diameter may be an under-recognized predictor of AVF maturation. Further study evaluating the effect of preoperative arterial diameter and other hemodynamic factors on AVF maturation is needed.

KDOQI Clinical Practice Guideline for Vascular Access: 2019 Update.

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

Long-Term Outcomes of Arteriovenous Fistulas with Unassisted versus Assisted Maturation: A Retrospective National Hemodialysis Cohort Study.

BACKGROUND: About half of arteriovenous fistulas (AVFs) require one or more interventions before successful dialysis use, a process called assisted maturation. Previous research suggested that AVF abandonment and interventions to maintain patency after maturation may be more frequent with assisted maturation versus unassisted maturation. METHODS: Using the US Renal Data System, we retrospectively compared patients with assisted versus unassisted AVF maturation for postmaturation AVF outcomes, including functional primary patency loss (requiring intervention after achieving AVF maturation), AVF abandonment, and frequency of interventions. RESULTS: We included 7301 patients ≥67 years who initiated hemodialysis from July 2010 to June 2012 with a catheter and no prior AVF; all had an AVF created within 6 months of starting hemodialysis and used for dialysis (matured) within 6 months of creation, with 2-year postmaturation follow-up. AVFs matured without prior intervention for 56% of the patients. Assisted AVF maturation with one, two, three, or four or more prematuration interventions occurred in 23%, 12%, 5%, and 4% of patients, respectively. Patients with prematuration interventions had significantly increased risk of functional primary patency loss compared with patients who had unassisted AVF maturation, and the risk increased with the number of interventions. Although the likelihood of AVF abandonment was not higher among patients with up to three prematuration interventions compared with patients with unassisted AVF maturation, it was significantly higher among those with four or more interventions. CONCLUSIONS: For this cohort of patients undergoing assisted AVF maturation, we observed a positive association between the number of prematuration AVF interventions and the likelihood of functional primary patency loss and frequency of postmaturation interventions.

Second-Chance Placement of Hemodialysis Patients After Involuntary Discharge for Disruptive Behavior.

A small subset of hemodialysis patients exhibits persistently disruptive behavior. When all reasonable attempts to stop such behavior have been exhausted, they may undergo involuntary discharge from their dialysis unit. Such patients typically present repeatedly to the emergency department for urgent inpatient dialysis. We describe a novel approach to achieve a successful "second-chance" placement at a new outpatient dialysis unit. The patients were required to dialyze in the inpatient unit for a minimum of 3 months, during which their compliance and behavior were observed closely. In parallel, an experienced social worker in the emergency department applied a structured protocol. The approach included debriefing about the incident leading to the discharge, coaching about building a trusting relationship with the nephrologist and dialysis staff, education about constructive handling of grievances, and arranging a face-to-face office interview with the medical director to determine their potential acceptance. Finally, the emergency department social worker conducted a formal handoff with the social worker at the accepting facility. During a 4-year period, we accrued 12 patients with an involuntary discharge. Following this protocol, 7 of them have been successfully placed at a new outpatient dialysis unit for 77 to 650 days without recurrence of disruptive behavior.

Complications of Hemodialysis Catheter Bloodstream Infections: Impact of Infecting Organism.

BACKGROUND: Catheter-related bloodstream infections -(CRBSI) are associated with a high burden of morbidity and mortality, but the impact of infecting organism on clinical outcomes has been poorly studied. METHODS: This retrospective analysis of a prospective vascular access database from a large academic dialysis center investigated whether the organism type affected the clinical presentation or complications of CRBSI. RESULTS: Among 339 patients with suspected CRBSI, an alternate source of infection was identified in 50 (15%). Of 289 patients with CRBSI, 249 grew a single organism and 40 were polymicrobial. Fever and/or rigors were presenting signs in ≥90% of patients with Staphylococcus aureus or Gram-negative CRBSI, but only 61% of Staphylococcus epidermidis infections (p < 0.001). Hospitalization occurred in 67% of patients with S. aureus CRBSI versus 34% of those with S. epidermidis and 40% of those with a Gram-negative bacteria (p < 0.001). Admission to the intensive care unit was required in 14, 9, and 2% (p = 0.06); metastatic infection occurred in 10, 4, and 4% (p = 0.42); and median length of stay among patients admitted to the hospital was 4, 4, and 5.5 days (p = 0.60), respectively. Death due to CRBSI occurred in only 1% of patients with CRBSI. CONCLUSION: CRBSI is confirmed in 85% of catheter-dependent hemodialysis patients in whom it is suspected. S. epidermidis CRBSI tends to present with atypical symptoms. S. aureus CRBSI is more likely to require hospitalization or intensive care admission. Metastatic infection is relatively uncommon, and death due to CRBSI is rare.

Clinical Outcomes and Economic Impact of Starting Hemodialysis with a Catheter after Predialysis Arteriovenous Fistula Creation.

BACKGROUND: Patients with advanced chronic kidney disease frequently undergo arteriovenous fistula creation prior to reaching end-stage renal disease (ESRD), but some initiate hemodialysis with a central vein catheter, if their fistula is not yet usable. The clinical consequences of the delay in fistula use have not been quantified in such patients. We compared patients with pre-ESRD fistula surgery who initiated dialysis with a catheter versus a fistula in terms of the frequency of post-dialysis vascular access procedures and complications and their economic impact. METHODS: We identified 205 patients with predialysis fistula creation from 2006 to 2012 at a large dialysis center who started hemodialysis within the ensuing 2 years. Of these, 91 (44%) initiated dialysis with a catheter and 114 (56%) with a fistula. We compared these 2 groups in terms of their annual frequency of percutaneous vascular access procedures, surgical access procedures, total access procedures, hospitalizations due to catheter-related bacteremia, and overall cost of vascular access management. RESULTS: The 2 groups were similar in demographics, comorbidities, and fistula type. As compared to patients initiating dialysis with a fistula, those initiating with a catheter had a significantly greater annual frequency of percutaneous access procedures (1.29 [1.19-1.40] vs. 0.75 [0.68-0.82]), surgical access procedures (0.69 [0.61-0.76] vs. 0.59 [0.53-0.66]), total access procedures (1.98 [1.86-2.11] vs. 1.34 [1.26-1.44]), and hospitalizations due to catheter-related bacteremia (0.09 [0.07-0.12] vs. 0.02 [0.01-0.03]). Patients initiating dialysis with a catheter incurred a median overall annual cost of access management that was USD 2,669 higher (USD 6,372 [3,121-12,242) vs. USD 3,703 [1,867-6,953], p = 0.0001). CONCLUSION: Among patients with predialysis fistula creation, those initiating dialysis with a catheter versus a fistula had substantially more frequent percutaneous, surgical, and total vascular access procedures, as well as hospitalizations due to catheter-related bacteremia. The annual cost of access management was substantially higher in those initiating dialysis with a catheter.

Gender Disparities in Vascular Access Surgical Outcomes in Elderly Hemodialysis Patients.

BACKGROUND: Despite national vascular access guidelines promoting the use of arteriovenous fistulas (AVF) over arteriovenous grafts (AVGs) for dialysis, AVF use is substantially lower in females. We assessed clinically relevant AVF and AVG surgical outcomes in elderly male and female patients initiating hemodialysis with a central venous catheter (CVC). METHODS: Using the United States Renal Data System standard analytic files linked with Medicare claims, we assessed incident hemodialysis patients in the United States, 9,458 elderly patients (≥67 years; 4,927 males and 4,531 females) initiating hemodialysis from July 2010 to June 2011 with a catheter and had an AVF or AVG placed within 6 months. We evaluated vascular access placement, successful use for dialysis, assisted use (requiring an intervention before successful use), abandonment after successful use, and rate of interventions after successful use. RESULTS: Females were less likely than males to receive an AVF (adjusted likelihood 0.57, 95% CI 0.52-0.63). Among patients receiving an AVF, females had higher adjusted likelihoods of unsuccessful AVF use (hazard ratio [HR] 1.46, 95% CI 1.36-1.56), assisted AVF use (OR 1.34, 95% CI 1.17-1.54), and AVF abandonment (HR 1.28, 95% CI 1.10-1.50), but similar relative rate of AVF interventions after successful use (relative risk [RR] 1.01, 95% CI 0.94-1.08). Among patients receiving an AVG, females had a lower likelihood of unsuccessful AVG use (HR 0.83, 95% CI 0.73-0.94), similar rates of assisted AVG use (OR 1.05, 95% CI 0.78-1.40) and AVG abandonment, and greater relative rate of interventions after successful AVG use (RR 1.16, 95% CI 1.01-1.33). CONCLUSIONS: While AVFs should be considered the preferred vascular access in most circumstances, clinical AVF surgical outcomes are uniformly worse in females. Clinicians should also consider AVGs as a viable alternative in elderly female patients initiating hemodialysis with a CVC to avoid extended CVC dependence.

Mineral Metabolism Disturbances and Arteriovenous Fistula Maturation.

BACKGROUND: The arteriovenous fistula (AVF) is central to haemodialysis treatment, but up to half of surgically created AVF fail to mature. Chronic kidney disease often leads to mineral metabolism disturbances that may interfere with AVF maturation through adverse vascular effects. This study tested associations between mineral metabolism markers and vein histology at AVF creation and unassisted and overall clinical AVF maturation. METHODS: Concentrations of fibroblast growth factor 23, parathyroid hormone, calcium, phosphate, and vitamin D metabolites: 1,25(OH)2D, 24,25(OH)2D, 25(OH)D, and bioavailable 25(OH)D were measured in pre-operative serum samples from 562 of 602 participants in the Haemodialysis Fistula Maturation Study, a multicentre, prospective cohort study of patients undergoing surgical creation of an autologous upper extremity AVF. Unassisted and overall AVF maturation were ascertained for 540 and 527 participants, respectively, within nine months of surgery or four weeks of dialysis initiation. Study personnel obtained vein segments adjacent to the portion of the vein used for anastomosis, which were processed, embedded, and stained for measurement of neointimal hyperplasia, calcification, and collagen deposition in the medial wall. RESULTS: Participants in this substudy were 71% male, 43% black, and had a mean age of 55 years. Failure to achieve AVF maturation without assistance occurred in 288 (53%) participants for whom this outcome was determined. In demographic and further adjusted models, mineral metabolism markers were not significantly associated with vein histology characteristics, unassisted AVF maturation failure, or overall maturation failure, other than a biologically unexplained association of higher 24,25(OH)2D with overall failure. This exception aside, associations were non-significant for continuous and categorical analyses and relevant subgroups. CONCLUSIONS: Serum concentrations of measured mineral metabolites were not substantially associated with major histological characteristics of veins in patients undergoing AVF creation surgery, or with AVF maturation failure, suggesting that efforts to improve AVF maturation rates should increase attention to other processes such as vein mechanics, anatomy, and cellular metabolism among end stage renal disease patients.

Fibrotic Venous Remodeling and Nonmaturation of Arteriovenous Fistulas.

The frequency of primary failure in arteriovenous fistulas (AVFs) remains unacceptably high. This lack of improvement is due in part to a poor understanding of the pathobiology underlying AVF nonmaturation. This observational study quantified the progression of three vascular features, medial fibrosis, intimal hyperplasia (IH), and collagen fiber organization, during early AVF remodeling and evaluated the associations thereof with AVF nonmaturation. We obtained venous samples from patients undergoing two-stage upper-arm AVF surgeries at a single center, including intraoperative veins at the first-stage access creation surgery and AVFs at the second-stage transposition procedure. Paired venous samples from both stages were used to evaluate change in these vascular features after anastomosis. Anatomic nonmaturation (AVF diameter never ≥6 mm) occurred in 39 of 161 (24%) patients. Neither preexisting fibrosis nor IH predicted AVF outcomes. Postoperative medial fibrosis associated with nonmaturation (odds ratio [OR], 1.55; 95% confidence interval [95% CI], 1.05 to 2.30; P=0.03, per 10% absolute increase in fibrosis), whereas postoperative IH only associated with failure in those individuals with medial fibrosis over the population's median value (OR, 2.63; 95% CI, 1.07 to 6.46; P=0.04, per increase of 1 in the intima/media ratio). Analysis of postoperative medial collagen organization revealed that circumferential alignment of fibers around the lumen associated with AVF nonmaturation (OR, 1.38; 95% CI, 1.03 to 1.84; P=0.03, per 10° increase in angle). This study demonstrates that excessive fibrotic remodeling of the vein after AVF creation is an important risk factor for nonmaturation and that high medial fibrosis determines the stenotic potential of IH.

Prediction of Arteriovenous Fistula Clinical Maturation from Postoperative Ultrasound Measurements: Findings from the Hemodialysis Fistula Maturation Study.

BACKGROUND: The utility of early postoperative ultrasound measurements in predicting arteriovenous fistula (AVF) clinical maturation is uncertain. METHODS: We investigated the relationships of ultrasound parameters with AVF clinical maturation in newly created AVF, measured at 1 day and 2 and 6 weeks, in 602 participants of a multicenter, observational cohort study. A backward elimination algorithm identified ultrasound measurements that independently predicted unassisted and overall AVF maturation. Candidate variables included AVF blood flow, diameter, and depth, upper arm arterial diameter, presence of stenosis, presence of accessory veins, seven case-mix factors (age, sex, black race, AVF location, diabetes, dialysis status, and body mass index), and clinical center. We evaluated the accuracy of the resulting models for clinical prediction. RESULTS: At each ultrasound measurement time, AVF blood flow, diameter, and depth each predicted in a statistically significant manner both unassisted and overall clinical maturation. Moreover, neither the remaining ultrasound parameters nor case-mix factors were associated with clinical AVF maturation after accounting for blood flow, diameter, and depth, although maturation probabilities differed among clinical centers before and after accounting for these parameters. The crossvalidated area under the receiver operating characteristic curve for models constructed using these three ultrasound parameters was 0.69, 0.74, and 0.79 at 1 day and 2 and 6 weeks, respectively, for unassisted AVF clinical maturation and 0.69, 0.71, and 0.76, respectively, for overall AVF maturation. CONCLUSIONS: AVF blood flow, diameter, and depth moderately predicted unassisted and overall AVF clinical maturation. The other factors considered did not further improve AVF maturation prediction.

Tradeoffs in Vascular Access Selection in Elderly Patients Initiating Hemodialysis With a Catheter.

RATIONALE & OBJECTIVE: National vascular access guidelines recommend placement of arteriovenous fistulas (AVFs) over grafts (AVGs) in hemodialysis patients, but have not been comprehensively assessed in the elderly. We evaluated clinically relevant vascular access outcomes in elderly patients receiving an AVF or AVG after hemodialysis therapy initiation. STUDY DESIGN: Retrospective cohort study using national administrative data. SETTINGS & PARTCIPANTS: Claims data from the US Renal Data System of 9,458 US patients 67 years and older who initiated hemodialysis therapy from July 1, 2010, to June 30, 2011, with a catheter and received an AVF (n=7,433) or AVG (n=2,025) within the ensuing 6 months. PREDICTOR: Arteriovenous access subtype, AVF or AVG. OUTCOMES: Successful use of vascular access, interventions to make vascular access functional, duration of catheter dependence before successful use of vascular access, frequency of interventions, and abandonment after successful use of vascular access. ANALYTICAL APPROACH: Multivariable logistic regression analysis was used to compare the need for intervention before successful use of AVFs and AVGs, and negative bionomial regression was used to calculate the frequency of intervention after successful use of vascular access. RESULTS: Unsuccessful use of vascular access within 6 months of creation was higher for AVFs versus AVGs (51% vs 45%; adjusted HR, 1.86; 95% CI, 1.73-1.99). Interventions to make vascular access functional were greater in AVFs versus AVGs (42% vs 23%; OR, 2.66; 95% CI, 2.26-3.12). AVFs had a lower 1-year abandonment rate after successful use compared with AVGs (OR, 0.71; 95% CI, 0.62-0.83) and required one-fourth fewer interventions after successful use (relative risk, 0.75; 95% CI, 0.69-0.81). Patients receiving an AVF had substantially longer catheter dependence before successful use than those receiving an AVG (median time, 3 vs 1 month; P<0.001). LIMITATIONS: Residual confounding due to vascular access choice, restriction to an elderly population, and 1-year follow-up period. CONCLUSIONS: In elderly hemodialysis patients initiating hemodialysis therapy with a catheter, the optimal vascular access selection depends on tradeoffs between shorter catheter dependence and less frequent interventions to make the vascular access (AVG) functional versus longer access patency and fewer interventions after successful use of the vascular access (AVF).

Relationships Between Clinical Processes and Arteriovenous Fistula Cannulation and Maturation: A Multicenter Prospective Cohort Study.

BACKGROUND: Half of surgically created arteriovenous fistulas (AVFs) require additional intervention to effectively support hemodialysis. Postoperative care and complications may affect clinical maturation. STUDY DESIGN: Hemodialysis Fistula Maturation (HFM) Study, a 7-center prospective cohort study. SETTING & PARTICIPANTS: 491 patients with single-stage AVFs who had neither thrombosis nor AVF intervention before a 6-week postoperative ultrasonographic examination and who required maintenance hemodialysis. PREDICTORS: Postoperative care processes and complications. OUTCOMES: Attempted cannulation, successful cannulation, and unassisted and overall clinical maturation as defined by the HFM Study criteria. RESULTS: AVF cannulation was attempted in 443 of 491 (90.2%) participants and was eventually successful in 430 of these 443 (97.1%) participants. 263 of these 430 (61.2%) reached unassisted and 118 (27.4%) reached assisted AVF maturation (overall maturation, 381/430 [88.6%]). Attempted cannulation was less likely in patients of surgeons with policies for routine 2-week versus later-than-2-week first postoperative visits (OR, 0.21; 95% CI, 0.06-0.70), routine second postoperative follow-up visits (OR, 0.39; 95% CI, 0.15-0.97), and a routine clinical postoperative ultrasound (OR, 0.28; 95% CI, 0.14-0.55). Attempted cannulation was also less likely among patients undergoing procedures to assist maturation (OR, 0.51; 95% CI, 0.27-0.98). Unassisted maturation was more likely for patients treated in facilities with access coordinators (OR, 1.91; 95% CI, 1.17-3.12), but less likely after precannulation nonstudy ultrasounds (OR per ultrasound, 0.42 [95% CI, 0.26-0.68]) and initial unsuccessful cannulation attempts (OR per each additional attempt, 0.90 [95% CI, 0.83-0.98]). Overall maturation was less likely with infiltration before successful cannulation (OR, 0.44; 95% CI, 0.22-0.89). Among participants receiving maintenance hemodialysis before AVF surgery, unassisted and overall maturation were less likely with longer intervals from surgery to initial cannulation (ORs for each additional month of 0.81 [95% CI, 0.76-0.88] and 0.93 [95% CI, 0.89-0.98], respectively) and from initial to successful cannulation (ORs for each additional week of 0.87 [95% CI, 0.81-0.94] and 0.88 [95% CI, 0.83-0.94], respectively). LIMITATIONS: Surgeons' management policies were assessed only by questionnaire at study onset. Most participants received upper-arm AVFs, planned 2-stage AVFs were excluded, and maturation time windows were imposed. Some care processes may have been missed and the observational design limits causal attribution. CONCLUSIONS: Multiple processes of care and complications are associated with AVF maturation outcomes.

Choice of a second vascular access in hemodialysis patients whose initial arteriovenous fistula failed to mature.

OBJECTIVE: We have previously shown that arteriovenous fistulas (AVFs) are more expensive to create and to maintain than arteriovenous grafts (AVGs) in patients undergoing their first access. Because those for whom this first access fails may be a more disadvantaged group, we hypothesized that the cost of a second access may be different from that in the primary access group. With this in mind, we compared access costs in patients receiving a secondary AVF or AVG after their initial AVF failed to mature. METHODS: This was a retrospective cohort study of 92 patients who received a second vascular access (44 AVFs and 48 AVGs) after their first AVF failed to mature. We quantified the yearly frequency of percutaneous or surgical access interventions and catheter-related bacteremias (CRBs) using a computerized vascular access database. The costs associated with access procedures were quantified using the outpatient prospective payment schedule, and those related to hospitalization for CRB were determined from the diagnosis-related groups fee schedule. RESULTS: Patients receiving an AVF had fewer percutaneous procedures than those receiving an AVG (2.09 [95% confidence interval, 1.86-2.34] vs 2.61 [2.35-2.88]; P = .004), tended to undergo surgical interventions more frequently (1.21 [1.04-1.40] vs 1.00 [0.84-1.17]; P = .08), and experienced a similar yearly frequency of CRB hospitalizations (0.40 [0.31-0.52 vs 0.28 [0.20-0.38]; P = .07). Patients with a secondary AVF vs an AVG had a similar median yearly cost of percutaneous access interventions ($3567 [interquartile range, $1219-$4680] vs $4989 [$1570-$9752]; P = .14) and surgical access procedures ($6403 [$3494-$13,127] vs $4728 [$2563-$12,254]; P = .38) but a higher annual cost for CRBs ($3405 [$0-$12,825] vs $0 [$0-$5477]; P = .04). The total yearly access-related cost was similar in both groups ($19,477 [$9162-$36,916] vs $18,285 [$6850-$31,768]; P = .56). CONCLUSIONS: Patients undergoing a secondary AVF required more surgical procedures and sustained more bacteremia complications than patients undergoing a secondary AVG implantation. There was no significant difference in the total cost of access care for hemodialysis patients receiving a secondary AVF vs AVG.

Effect of Anti-Hypertensive Medication History on Arteriovenous Fistula Maturation Outcomes.

BACKGROUND: The arteriovenous fistula (AVF) is the preferred vascular access for hemodialysis. However, approximately half of AVFs fail to mature. The use of angiotensin converting enzyme inhibitors (ACE-Is), angiotensin receptor blockers (ARBs), and calcium channel blockers (CCBs) exerts favorable endothelial effects and may promote AVF maturation. We tested associations of ACE-I and ARBs, CCBs, beta-blockers, and diuretics with the maturation of newly created AVFs. METHODS: We evaluated 602 participants from the Hemodialysis Fistula Maturation Study, a multi-center, prospective cohort study of AVF maturation. We ascertained the use of each medication class within 45 days of AVF creation surgery. We defined maturation outcomes by clinical use within 9 months of surgery or 4 weeks of initiating hemodialysis. RESULTS: Unassisted AVF maturation failure without intervention occurred in 54.0% of participants, and overall AVF maturation failure (with or without intervention) occurred in 30.1%. After covariate adjustment, CCB use was associated with a 25% lower risk of overall AVF maturation failure (95% CI 3%-41% lower) but a non-significant 10% lower risk of unassisted maturation failure (95% CI 23% lower to 5% higher). ACE-I/ARB, beta-blocker, and diuretic use was not significantly associated with AVF maturation outcomes. None of the antihypertensive medication classes were associated with changes in AVF diameter or blood flow over 6 weeks following surgery. CONCLUSIONS: CCB use may be associated with a lower risk of overall AVF maturation failure. Further studies are needed to determine whether CCBs might play a causal role in improving AVF maturation outcomes.

The Clinical and Economic Effect of Vascular Access Selection in Patients Initiating Hemodialysis with a Catheter.

Patients in the United States frequently initiate hemodialysis with a central venous catheter (CVC) and subsequently undergo placement of a new arteriovenous fistula (AVF) or arteriovenous graft (AVG). Little is known about the clinical and economic effects of initial vascular access choice. We identified 479 patients starting hemodialysis with a CVC at a large medical center (during 2004-2012) who subsequently had an AVF (n=295) or AVG (n=105) placed or no arteriovenous access (CVC group, n=71). Compared with patients receiving an AVG, those receiving an AVF had more frequent surgical access procedures per year (1.01 [95% confidence interval, 0.95 to 1.08] versus 0.62 [95% confidence interval, 0.55 to 0.70]; P<0.001) but a similar frequency of percutaneous access procedures per year. Patients receiving an AVF had a higher median annual cost (interquartile range) of surgical access procedures than those receiving an AVG ($4857 [$2523-$8835] versus $2819 [$1411-$4274]; P<0.001), whereas the annual cost of percutaneous access procedures was similar in both groups. The AVF group had a higher median overall annual access-related cost than the AVG group ($10,642 [$5406-$19,878] versus $6810 [$3718-$13,651]; P=0.001) after controlling for patient age, sex, race, and diabetes. The CVC group had the highest median annual overall access-related cost ($28,709 [$11,793-$66,917]; P<0.001), largely attributable to the high frequency of hospitalizations due to catheter-related bacteremia. In conclusion, among patients initiating hemodialysis with a CVC, the annual cost of access-related procedures and complications is higher in patients who initially receive an AVF versus an AVG.