Primary Arteriovenous Fistulas in the Forearm for Hemodialysis: Effect of Miscellaneous Factors in Fistula Patency

Sex disparities in hemodialysis access outcomes: A systematic review

The goal of this systematic review was to collate and summarize the current literature on hemodialysis access outcomes in females, identify differences between females and men, and provide a foundation for future research. A systematic review of the English-language literature was conducted by searching PubMed and Google Scholar for the following terms: "sex," "hemodialysis access," "arteriovenous fistula," "arteriovenous graft," and "dialysis catheter." Reference lists from the resulting articles were also evaluated to ensure that any and all relevant primary sources were identified. Studies were then screened by two independent reviewers for inclusion. Of 967 total studies, 53 ultimately met inclusion criteria. Females have lower maturation rates; have decreased rates of primary, primary-assisted, and secondary patency; require more procedures per capita to achieve maturation and to maintain fistula patency; are more likely to receive dialysis via an arteriovenous graft or central venous catheter; and require a longer time and potentially more assistive invasive interventions to achieve a mature fistula. Our findings emphasize the urgent need for further research to evaluate and address the causes of these disparities. Discussion with patients undergoing hemodialysis should include these findings to improve patient education, expectations, satisfaction, and outcomes.

Anesthetic choice for arteriovenous access creation: A National Anesthesia Clinical Outcomes Registry analysis

BACKGROUND

We sought to evaluate differences in primary anesthetic type used in arteriovenous access creation with the hypothesis that administration of regional anesthesia and monitored anesthesia care (MAC) with local anesthesia as the primary anesthetic has increased over time.

METHODS

National Anesthesia Clinical Outcomes Registry data were retrospectively evaluated. Covariates were selected a priori within multivariate models to determine predictors of anesthetic type in adults who underwent elective arteriovenous access creation between 2010 and 2018.

RESULTS

A total of 144,392 patients met criteria; 90,741 (62.8%) received general anesthesia. The use of regional anesthesia and MAC decreased over time (8.0%-6.8%, 36.8%-27.8%, respectively; both p < 0.0001). Patients who underwent regional anesthesia were more likely to have ASA physical status >III and to reside in rural areas (52.3% and 12.9%, respectively; both p < 0.0001). Patients who underwent MAC were more likely to be older, male, receive care outside the South, and reside in urban areas (median age 65, 56.8%, 68.1%, and 70.8%, respectively; all p < 0.0001). Multivariate analysis revealed that being male, having an ASA physical status >III, and each 5-year increase in age resulted in increased odds of receiving alternatives to general anesthesia (regional anesthesia adjusted odds ratios (AORs) 1.06, 1.12, and 1.26, MAC AORs 1.09, 1.2, and 1.1, respectively; all p < 0.0001). Treatment in the Midwest, South, or West was associated with decreased odds of receiving alternatives to general anesthesia compared to the Northeast (regional anesthesia AORs 0.28, 0.38, and 0.03, all p < 0.0001; MAC 0.76, 0.13, and 0.43, respectively; all p < 0.05).

CONCLUSIONS

Use of regional anesthesia and MAC with local anesthesia for arteriovenous access creation has decreased over time with general anesthesia remaining the primary anesthetic type. Anesthetic choice, however, varies with patient characteristics and geography.

The association of erythropoietin-stimulating agents and increased risk for AV-fistula dysfunction in hemodialysis patients. A retrospective analysis

BACKGROUND

Patients in maintenance hemodialysis (HD) need a patent vascular access for optimal treatment. The recommended first choice is a native arteriovenous fistula (AVF). Complications of AVF are frequent and include thrombosis, stenosis and infections leading to worsening of dialysis efficacy. Some known risk factors are age, gender and the presence of diabetes mellitus. The aim was to investigate if further risk variables are associated with dysfunctional AVF.

METHODS

This retrospective observational study included 153 chronic HD patients (Cases) referred to a total of 473 radiological investigations due to clinically suspected complications of their native AVF. Another group of chronic HD patients (n = 52) who had a native AVF but were without history of previous complications for at least 2 years were controls. Statistical analyses included ANOVA, logistic regression, parametric and non-parametric methods such as Student's T-test and Mann-Whitney test.

RESULTS

Among Cases, at least one significant stenosis (> 50% of the lumen) was detected in 348 occasions. Subsequent PTA was performed in 248 (71%). Median erythropoiesis-stimulating agent (ESA) weekly doses were higher in Cases than in Controls (8000 vs 5000 IU, p < 0.001). Cases received higher doses of intravenous iron/week than the Controls before the investigation (median 50 mg vs 25 mg, p = 0.004) and low molecular weight heparin (LMWH, p = 0.028). Compared to Controls, Cases had a lower level of parathyroid hormone (median 25 vs 20 ρmol/L, p = 0.009). In patients with diabetes mellitus, HbA1c was higher among Cases than Controls (50 vs 38 mmol/mol, p < 0.001). Multiple regression analysis revealed significant associations between Cases and female gender, prescription of doxazocin, and doses of ESA and LMWH. There was no difference between the groups regarding hemoglobin, CRP or ferritin.

CONCLUSION

In conclusion, the present study indicated that the factors associated with AVF problems were high doses of ESA, iron administration, and tendency of thromboembolism (indicated by high LMWH doses); the use of doxazocin prescription, however, requires further investigation.

Sex differences in the vascular access of hemodialysis patients: a cohort study

Background

We describe differences for probability of receiving a fistula attempt, achieving fistula use, remaining catheter-free and the rate of access-related procedures as a function of sex.

Methods

Prospectively collected vascular access data on incident dialysis patients from five Canadian programs using the Dialysis Measurement Analysis and Reporting System to determine differences in fistula-related outcomes between women and men. The probability of receiving a fistula attempt and the probability of fistula use were determined using binary logistic regression. Catheter and fistula procedure rates were described using Poisson regression. We studied time to fistula attempt and time to fistula use, accounting for competing risks.

Results

We included 1446 (61%) men and 929 (39%) women. Men had a lower body mass index (P < 0.001) and were more likely to have coronary artery disease (P < 0.001) and peripheral vascular disease (p < 0.001). A total of 688 (48%) men and 403 (43%) women received a fistula attempt. Women were less likely to receive a fistula attempt by 6 months {odds ratio [OR] 0.64 [95% confidence interval (CI) 0.52-0.79]} and to achieve catheter-free use of their fistula by 1 year [OR 0.38 (95% CI 0.27-0.53)]. At an average of 2.30 access procedures per person-year, there is no difference between women and men [incidence rate ratio (IRR) 0.97 (95% CI 0.87-1.07)]. Restricting to those with a fistula attempt, women received more procedures [IRR 1.16 (95% CI 1.04-1.30)] attributed to increased catheter procedures [IRR 1.50 (95% CI 1.27-1.78)]. There was no difference in fistula procedures [IRR women versus men 0.96 (95% CI 0.85-1.07)].

Conclusion

Compared with men, fewer women undergo a fistula attempt. This disparity increases after adjusting for comorbidities. Women have the same number of fistula procedures as men but are less likely to successfully use their fistula.

Outcomes of arteriovenous fistula creation: A Jordanian experience

Objective:

The arteriovenous fistula is considered the preferred hemodialysis access due to its lower complication rate and longer patency. The aim of this study is to report the outcomes of arteriovenous fistula creation and to study the predictive factors for these outcomes.

Study design and method:

This is a retrospective study of all patients who underwent autogenous arteriovenous fistula creation procedure by a single surgeon during the period from October 2011 till December 2017.

Material:

All the procedures were performed at an academic referral center by a single surgeon. All patients who underwent arteriovenous fistula creation in the upper limb during the study period were included. All patients were diagnosed with end-stage renal disease and referred for arteriovenous fistula creation either before or after initiating hemodialysis.

Method:

Data were collected from the patients’ charts. The primary outcomes were the primary failure and secondary patency rates. Secondary outcome was to find the factors associated with decreased patency. The Kaplan–Meier curve with the log-rank test was used to describe the patency while univariate and multivariate analyses were done to the factors considered relevant to the patency.

Results:

The total number of procedures was 291; of which, 18 were lost to follow-up. The primary failure rate was 12%. Secondary patency rate at 1 and 5 years was 79% and 53%, respectively. Diabetes mellitus and fistulae placed on right side were associated with decreased patency.

Conclusion:

The primary failure rate was relatively low in this study but the long-term functionality of the arteriovenous fistulae needs to be improved.

Endovascular Arteriovenous Dialysis Fistula Intervention: Outcomes and Factors Contributing to Fistula Failure

RATIONALE & OBJECTIVE

Primary patency is variable with arteriovenous fistulas, and many patients require angiographic procedures to obtain patency. Accordingly, we determined postintervention patency rates and contributing factors for fistula failure following intervention to establish secondary patency in non-dialysis-dependent patients with advanced chronic kidney disease following creation of an arteriovenous fistula.

STUDY DESIGN

Observational study from a single referral center.

SETTING & PARTICIPANTS

210 non-dialysis-dependent patients with advanced chronic kidney disease who underwent upper-extremity fistula creation for anticipated dialysis between October 1995 and January 2015 and who required subsequent endovascular therapy to establish or maintain patency were reviewed.

EXPOSURE

Endovascular therapy for dialysis arteriovenous fistula primary patency failure.

OUTCOMES

Postintervention patency duration following endovascular therapy.

ANALYTICAL APPROACH

Descriptive study with outcomes determined using Cox proportional hazards models.

RESULTS

Multiple fistula configurations were reviewed: 138 (65.7%) brachiocephalic, 39 (18.6%) radiocephalic, 30 (14.3%) brachiobasilic, 2 (1.0%) ulnocephalic, and 1 (0.5%) radiobasilic. There were 261 initial stenoses treated. Postintervention primary patency is defined as the time from the index intervention to repeat intervention for stenosis. Postintervention primary-assisted patency is the time from the index intervention to thrombectomy for fistula thrombosis or change in modality. Postintervention secondary patency is the time from the index intervention to fistula abandonment. Median postintervention primary patency, postintervention primary-assisted patency, and secondary patency were 2.7, 3.2, and 3.6 years, respectively. The overall 1-year primary, primary-assisted, and secondary patency rates in this cohort were 53.0%, 87.7%, and 83.5%, respectively. Compared with radiocephalic fistulas, brachiocephalic fistulas had higher risk for postintervention primary patency loss (HR, 1.90; 95% CI, 1.13-3.20; P = 0.02).

LIMITATIONS

Dialysis fistula revascularization techniques varied.

CONCLUSIONS

The radiocephalic fistula configuration had the best postintervention primary patency in this cohort. Postintervention primary-assisted patency and secondary patency were not significantly different among different fistula configurations.

Survival and Prognostic Predictors of Primary Arteriovenous Fistula for Hemodialysis

Objectives: This study aims to evaluate the survival and prognostic predictors of arteriovenous fistulas (AVFs) among patients undergoing AVF creation. The significant predictors were incorporated into a prognostic model to determine its prognostic performance for five-year AVF survival.

Materials and Methods: Data on 290 patients who underwent first-time AVF creation and who had been followed up for at least 5 years or until AVF failure were reviewed. The Kaplan–Meier survival curves and Cox proportional hazards model were generated to determine the AVF survival and associated prognostic predictors. Significant predictors were used to derive a prognostic model.

Results: The mean age of the patients was 59.7±14.6 years, and the 5-year AVF survival rate was 34.5%. Three features were found to be independent prognostic factors for the five-year AVF survival: old age, diabetes mellitus, and prior central venous catheter placement. These three significant factors were integrated into a prognostic scoring model that ranged from zero to five points. According to this model, the patients whose scores were 0, 1, 2, 3 and 4 or more had five-year AVF survival rates of 60.0%, 45.3%, 36.6%, 15.0%, and 2.9%, respectively.

Conclusion: The five-year survival rate of AVFs was modest, and a prognostic model could excellently estimate the five-year AVF survival.

Factors affecting arteriovenous fistula dysfunction: A narrative review

Vascular access dysfunction is one of the most important causes of morbidity and mortality in haemodialysis patients, contributing to up to one third of hospitalisations and accounting for a significant amount of the health care costs of these patients. In the past decades, significant scientific advances in understanding mechanisms of arteriovenous fistula maturation and failure have contributed to an increase in the amount of research into techniques for creation and strategies for arteriovenous fistula dysfunction prevention and treatment, in order to improve patient care and outcomes. The aim of this review is to describe the pathogenesis of vascular access failure and provide a comprehensive analysis of the associated risk factors and causes of vascular access failure, in order to interpret possible future therapeutic approaches. Arteriovenous fistula failure is a multifactorial process resulting from the combination of upstream and downstream events with consequent venous neo-intimal hyperplasia and/or inadequate outward remodelling. Inflammation appears to be central in the biology of arteriovenous fistula dysfunction but important triggers still need to be revealed. Given the significant association of arteriovenous fistula failure and patient's prognosis, it is therefore imperative to further research in this area in order to improve prevention, surveillance and treatment, and ultimately patient care and outcomes.

Spanish Clinical Guidelines on Vascular Access for Haemodialysis

Vascular access for haemodialysis is key in renal patients both due to its associated morbidity and mortality and due to its impact on quality of life. The process, from the creation and maintenance of vascular access to the treatment of its complications, represents a challenge when it comes to decision-making, due to the complexity of the existing disease and the diversity of the specialities involved. With a view to finding a common approach, the Spanish Multidisciplinary Group on Vascular Access (GEMAV), which includes experts from the five scientific societies involved (nephrology [S.E.N.], vascular surgery [SEACV], vascular and interventional radiology [SERAM-SERVEI], infectious diseases [SEIMC] and nephrology nursing [SEDEN]), along with the methodological support of the Cochrane Center, has updated the Guidelines on Vascular Access for Haemodialysis, published in 2005. These guidelines maintain a similar structure, in that they review the evidence without compromising the educational aspects. However, on one hand, they provide an update to methodology development following the guidelines of the GRADE system in order to translate this systematic review of evidence into recommendations that facilitate decision-making in routine clinical practice, and, on the other hand, the guidelines establish quality indicators which make it possible to monitor the quality of healthcare.

Arteriovenous shunts as venous access in children with haemophilia

INTRODUCTION

Venous access is essential in patients with haemophilia for administration of factor concentrates. Peripheral venipuncture may be challenging, particularly in young children or during immune tolerance induction (ITI). Central venous access devices (CVADs) carry a significant risk for complications. An alternative for venous access is peripheral arteriovenous shunts (AVSs), but there is sparse documentation in the literature. The aim of this study was to document our experience with AVS over 12 years in 27 boys with severe haemophilia.

METHODS

For AVS creation, a subcutaneous vein is connected end-to-side with an artery at the wrist (Cimino) or at the forearm (Gracz shunt). Factor concentrates were substituted as for intermediate size surgery. To prevent shunt occlusion, heparin (5 units/kg/h) was given during the first 3 days.

RESULTS

Indications for AVS creation were prophylaxis start (n = 20) and ITI (n = 7). Age at shunt insertion was median 1.5 years (minimum 8 months; maximum 11.7 years). Shunt maturation was achieved within a median of 3 weeks after surgery (1.5 weeks; 18 weeks). Age when home treatment was established was median 2.1 years (9 months; 11.7 years). Four patients required AVS revisions due to stenosis, but 26 of 27 patients (96%) achieved good long-term shunt function. There were few other complications.

CONCLUSION

Arteriovenous shunts provide a good alternative to CVAD and carry a lower risk of complications. AVSs allow earlier start of prophylaxis and home therapy with an improved quality of life for patients and families.

Arteriovenous Fistulae vs. Arteriovenous Grafts: A Retrospective Review of 1,700 Consecutive Vascular access Cases

Objective

Vascular access (VA) procedures are rapidly becoming the most prevalent surgery in the United States. It is estimated that there will be over 500,000 VA procedures done this year. Previously, surgeons in the US were attempting many more non-autogenous grafts than autogenous fistulae. In recent years, there has been a great push called “Fistula First” to promote arteriovenous fistulae (AVF) as the first line of treatment vs. non-autogenous grafts. The goal of this investigation is to determine if too many fistulae are now being performed without attention to specific patient profiles.

Methods

A retrospective review of 1700 consecutive cases was performed by one surgeon at one institution between 1997 and 2005. Patients were categorized by demographics, co-morbidities, previous access procedures, access location, and type of graft. Patency was calculated. Kaplan-Meier, Cox regression and the Log Rank Test were used to analyze data. Access endpoints and complications were also documented.

Results

The study reviewed 1700 procedures. The median age was 52 (60.2% male) with 58.7% fistulae and 41.3% grafts. Median patency time was 10 months, with no statistically significant difference between access types. There was no significant difference in length of patency when comparing upper arm (70.1%), lower arm (24.5%) and thigh (5.4%). Graft infection rate was 9.5% and fistula infection rate was 0.9% (p<0.001). The overall infection rate was 4.5%, and decreased patency significantly (4 vs. 11 months). Thrombosis occurred in 24.7% of grafts and 9.0% of fistulae. Thrombosed grafts had better salvage rates (8 vs. 4 months, p<0.001). The data showed diabetes, HTN and HIV have no overall impact on patency.

Conclusions

AVF and grafts are both useful in providing VA for patients requiring hemodialysis. Our data shows that grafts are equivalent in long-term patency. Therefore, it is apparent in those patients who are not candidates for an AV fistula; an AV graft for VA should be placed.

Genotype polymorphisms of genes regulating nitric oxide synthesis determine long-term arteriovenous fistula patency in male hemodialysis patients

OBJECTIVES

Nitric oxide (NO) is a pivotal vasoactive substance modulating arteriovenous fistula (AVF) patency for hemodialysis (HD). Since genetic background could be the predicting factor of AVF malfunction, we aimed to investigate whether the NO-related genotype polymorphisms determine AVF survival rates.

METHODS

This is a retrospective, observational, multi-center study involving eight HD units in Taiwan, enrolled 580 patients initiating maintenance HD via AVFs. Genotype polymorphisms of NO-biosynthesis regulating enzymes (DDAH-1, DDAH-2, eNOS and PRMT1) were compared between HD patients with (n = 161) and without (n = 419) history of AVF malfunction. Subgroup analyses by gender were performed to evaluate the genetic effect in difference sexes.

RESULTS

In overall population, statistically significant associations were not found between AVF malfunction and the genetic polymorphisms. In the male subgroup (n = 313), a single nucleotide polymorphism (SNP) of PRMT1, rs10415880 (IVS9-193 A/G), showed a significant association with AVF malfunction. Male patients with AA/AG genotype had inferior AVF outcomes compared to GG genotype, regarding primary patency (70.6% vs. 40.9%, p = 0.001), assisted primary patency (81.0% vs. 58.4%, p < 0.001) and secondary patency (83.7% vs. 63.3%, p < 0.001) at a 5-year observation period. From multivariate Cox regression model, the AA/AG genotypes of PRMT1 were an independent risk factor for AVF malfunction in men (HR: 4.539, 95% CI 2.015-10.223; p < 0.001). However, such associations were not found in women.

CONCLUSIONS

rs10415880, the SNP of PRMT1 could be a novel genetic marker associated with AVF malfunction risk in male HD patients. Those with AA and AG genotypes of rs10415880 may predict a poorer long-term patency of AVF.

Patterns of Dialysis Initiation Affect Outcomes of Incident Hemodialysis Patients

AIMS

There is a trend toward deferring the initiation of chronic dialysis until absolutely indicated. This strategy, however, might lead to increased uncertainties in the timing of dialysis access creation prior to dialysis onset for patients approaching end-stage renal disease (ESRD), and the impact of which on hard end points remains largely unclear. We hereby investigated the effect of varied patterns of dialysis initiation on outcomes of new-onset hemodialysis (HD) patients.

METHODS

Four hundred sixty-two prospectively recruited patients were stratified into planned elective (n = 117, 25%), planned urgent (n = 65, 14%) or unplanned urgent (n = 280, 61%) starters based on the timing of access creation with respect to dialysis initiation. The outcome measures were all-cause mortality, hospitalization and access reconstruction over 2 years.

RESULTS

The mean estimated glomerular filtration rate (eGFR) was higher in the planned elective than in the planned urgent or unplanned urgent starters at access creation (5.3 vs. 4.4 or 4.3 ml/min/1.73 m2), but not at dialysis initiation (4.2 vs. 3.9 or 4.3 ml/min/1.73 m2). During the follow-up, the planned elective population exhibited the lowest rates of overall mortality and hospitalization, but not access reconstruction. Multivariate Cox's regression analysis showed that the planned urgent and the unplanned urgent groups, comparing to the planned elective population, displayed a greater risk of early death (hazards ratio [HR] 3.324, 95% CI 1.409-7.840; HR 2.510, 95% CI 1.177-5.355, respectively) and early hospitalization (sub-hazards ratio [SubHR] 2.238, 95% CI 1.530-3.274; SubHR 1.529, 95% CI 1.096-2.133, respectively).

CONCLUSION

Incident ESRD patients undergoing planned elective start of HD, compared to their planned or unplanned urgent counterparts, showed reduced risk of overall mortality and hospitalization in the first 2 years after commencing long-term dialysis at a mean eGFR <5 ml/min/1.73 m2.

Association Between Vascular Access Dysfunction and Subsequent Major Adverse Cardiovascular Events in Patients on Hemodialysis: A Population-Based Nested Case-Control Study

The association between dialysis vascular access dysfunction and the risk of developing major adverse cardiovascular events (MACE) in hemodialysis patients is unclear and has not yet been investigated. We analyzed data from the National Health Insurance Research Database of Taiwan to quantify this association. Adopting a case-control design nested within a cohort of patients who received hemodialysis from 2001 to 2010, we identified 9711 incident cases of MACE during the stage of stable maintenance dialysis and 19,422 randomly selected controls matched to cases on age, gender, and duration of dialysis. Events of vascular access dysfunction in the 6-month period before the date of MACE onset (ie, index date) for cases and before index dates for controls were evaluated retrospectively. The presence of vascular access dysfunction was associated with a 1.385-fold higher odds of developing MACE as estimated from the logistic regression analysis. This represents a significantly increased adjusted odds ratio (OR) at 1.268 (95% confidence interval [CI] = 1.186-1.355) after adjustment for comorbidities and calendar years of initiating dialysis. We also noted a significant exposure-response trend (P < 0.001) between the frequency of vascular access dysfunction and MACE, with the greatest risk (adjusted OR = 1.840, 95% CI = 1.549-2.186) noted in patients with ≥3 vascular access events. We concluded that dialysis vascular access dysfunction was significantly associated with an increased risk of MACE. Hence, vascular access failure can be an early sign for MACE in patients receiving maintenance hemodialysis. Active monitoring and treatment of cardiovascular risk factors and related diseases, not merely managing vascular access dysfunction, would be required to reduce the risk of MACE.

Hyperphosphatemia is associated with patency loss of arteriovenous fistula after 1 year of hemodialysis

BACKGROUND

The patency of arteriovenous access is important for stable and effective hemodialysis, and long-term technical survival is best achieved with a native arteriovenous fistula (AVF). However, maintaining AVF patency remains a challenge. This study was designed to determine the independent prognostic factors for AVF patency according to hemodialysis duration.

METHODS

The primary study end point was unassisted patency of the AVF, which was defined as the time from the first fistula surgery to the first AVF failure. AVF failure was defined as an event that required percutaneous intervention or surgery to revise or replace the fistula, which occurred at least 2 months after fistula formation.

RESULTS

We enrolled 478 patients with a mean age of 55.5±14.0 years, and mean duration of dialysis was 2.5±2.1 years. There were 109 cases (22.8%) of AVF failure. The factors related to AVF patency differed according to hemodialysis duration. Using a Cox-adjusted model, we observed a significant correlation between the incidence of AVF failure and diabetes within the initial 12 months of hemodialysis. Uncontrolled hyperphosphatemia (mean serum phosphorus>5.5 mg/dL during hemodialysis) was associated with patency loss of AVF after 1 year of hemodialysis.

CONCLUSION

Various factors were associated with the development of patency loss of AVF as hemodialysis duration differed, and a preventive role of hyperphosphatemia control in AVF survival needs further clinical study.

Compliance with surgical follow-up does not influence fistula maturation in a county hospital population

BACKGROUND

The purpose of this study is to examine follow-up rates and maturation rates after dialysis access surgery using a fistula-first approach in a county hospital with an indigent population.

METHODS

A prospectively maintained dialysis access database was queried for cases performed between August 1, 2009 and September 30, 2011. The follow-up period ended on December 31, 2011. An attempt was made to contact patients who did not have complete follow-up data recorded to the point of fistula maturation for arteriovenous fistulas (AVF). Patients were contacted directly or through their dialysis center. Maturation was defined by successful use of the AVF for hemodialysis for at least 2 weeks for patients who are dialysis dependent or by the clinical assessment of an attending vascular surgeon for those not on dialysis.

RESULTS

Two hundred three dialysis access cases were performed. The mean age was 51.4 years. One hundred twenty-six (62%) were male and 175 (86%) were Hispanic. Of these, 194 (95.6%) were AVF. Three AVF were ligated in the postoperative period for steal. Of the remaining 191 AVF, 94 (49%) patients completed their scheduled follow-up appointments. Sixty-six (35%) patients did not come to clinic but were contacted. Twenty-six (14%) patients were completely lost to follow-up and 5 (2.6%) died. Maturation data was obtained on 160 AVF. Of those, 123 (77%) reached maturation with a mean maturation time of 112 ± 99 days (range, 21-483). Twenty patients who completed follow-up underwent at least 1 additional surgical or endovascular procedure in an attempt to achieve maturation. Seventeen (85%) patients who underwent a secondary procedure went on to achieve maturation. There was no significant difference in maturation between the group that completed follow-up and those who were contacted by phone (69 [73%] vs. 54 [81%], P = not significant).

CONCLUSIONS

In this indigent population, follow-up does not influence maturation rates of AVF. Despite poor compliance with follow-up in the setting of a public hospital, the maturation rate of an aggressive fistula-first approach is acceptable.

Chronic kidney disease and dialysis access in women

Chronic kidney disease currently affects one in nine Americans and over 500,000 have progressed to failure requiring kidney replacement therapy, with nearly 45% being women. Clinical Practice Guidelines have been developed in an effort to synthesize the latest literature, particularly randomized controlled trials, to assist clinical decision making. Women have different levels of kidney function than men at the same level of serum creatinine and may also lose kidney function over time more slowly than men. Although the arteriovenous fistulae have long been recognized as the preferred access for hemodialysis, women are less likely to initiate dialysis with an arteriovenous fistula in place. In addition, the female sex is regarded as a risk factor for access failure as well for complications such as steal. This article reviews treatment of women with chronic kidney disease, focusing on the difficulties they are perceived to have with dialysis access.

Type of arteriovenous vascular access and association with patency and mortality

BACKGROUND

There are only a few risk factors known for primary patency loss in patients with an arteriovenous graft or fistula. Furthermore, a limited number of studies have investigated the association between arteriovenous access modality and primary patency loss and mortality. The aim of this study was to investigate risk factors for patency loss and to investigate the association between graft versus fistula use and outcomes (patency loss and mortality).

METHODS

We prospectively followed 919 incident hemodialysis patients and calculated hazard ratios (HRs) for putative risk factors of primary patency loss using Cox regression. Furthermore, HRs were calculated to study the association between graft versus fistula use and two-year primary patency loss and two-year mortality.

RESULTS

Cardiovascular disease, prior catheter use, lowest tertile of albumin, highest tertile of hsCRP, and lowest tertile of fetuin-A were associated with primary patency loss in both patients with grafts and fistulas. Increased age, female sex, and diabetes mellitus were only associated with primary patency loss in patients with a fistula. We did not observe an association between primary patency loss and BMI, residual GFR, levels of calcium, phosphorus, and total cholesterol. Furthermore, graft use as compared with fistula use was associated with an 1.4-fold (95% CI 1.0-1.9) increased risk of primary patency loss and with an 1.5-fold(95% CI 1.0-2.2) increased mortality risk.

CONCLUSION

Cardiovascular disease, prior catheter use, albumin, hsCRP, and fetuin-A are risk factors for patency loss. Graft use as compared with fistula use was associated with an increased risk of patency loss and mortality.

Prevention better than cure. Avoiding steal syndrome with proximal radial or ulnar arteriovenous fistulae

BACKGROUND

Steal syndrome is a significant complication of arteriovenous fistulae (AVF). We wanted to assess an alternative technique to reduce the incidence of steal syndrome and add an extra option for vascular access for long-term hemodialysis patients

METHODS

All patients who underwent proximal radial or ulnar artery AVF between 2003 and 2007 were evaluated retrospectively.

RESULTS

There were 58 patients, 35 men and 23 women, and the median age was 60 years (range 19-85 years). The proximal radial artery was used in 50 (89%) of cases and the ulnar artery in 8. Three fistulae (5%) failed in the first week, 3 others failed later, prior to use leading to a 90% successful patency rate. One diabetic patient developed steal syndrome and re-presented to the surgeons at a late stage when they had finger ulceration and it was decided to ligate the fistula in this case. Thus, the overall incidence of steal syndrome was low at 2%.

CONCLUSIONS

It is suggested that arterio-venous fistulae using proximal radial or ulnar arteries can be performed before brachio-cephalic fistulae since they offer long-term patency and reduced incidence of steal syndrome. Brachio-cephalic AVF can be performed subsequently if necessary.

An experience of arteriovenous fistulas created for hemodialysis in the largest health center in eastern Turkey

BACKGROUND

The aim of the study was to evaluated the primary and secondary (after reoperation) patency rates and some effect factors in fistula patency for hemodialysis patients.

MATERIAL AND METHODS

Over a 10-year period, 1529 arteriovenous fistulas (AVFs) were fashioned in 1003 (611 males, 392 females; median age range 7-72) patients using the native vascular tissue and prosthetic graft material. We also evaluated the effects of various factors in fistula patency and primary and secondary patency rates in AVF patients.

RESULTS

The primary patencies of fistulas in this series were 72%, 64%, 51%, 41%, and 26%, and secondary patencies were 79%, 70%, 56%, 46%, and 33% at 6 months, 1, 2, 4, and 6 years, respectively. There was no statistically significant difference between the primary and secondary patencies (p = 0.082) in the 6-year follow-up. Factors affecting the patency of fistulas were diabetes mellitus (p < 0.005), hypertension (p < 0.005), and smoking habits (p < 0.005).

CONCLUSION

Even if shown to be not statistically significant, successful surgical revision after fistula occlusion improves secondary patency with potential benefits in terms of patient morbidity. Besides, the AVF patency was shortened in chronic renal-insufficiency patients with diabetes mellitus, hypertension, and smoking habits.

Factors affecting the patency of arteriovenous fistulas for dialysis access

BACKGROUND

The autologous arteriovenous fistula (AVF) is the accepted gold standard mode of repeated vascular access for hemodialysis in terms of access longevity, patient morbidity, and health care costs. This review assesses the current evidence supporting the role of various patient and surgeon factors on AVF patency.

METHODS

The literature was searched to identify the current evidence available for patient characteristics, methods of AVF planning, and anatomic factors that may affect patency outcomes after AVF formation. The use of adjuvant medications, surgical techniques, and policies for AVF maintenance are discussed in relation to AVF patency.

RESULTS

Current literature supports patient factors, such as increasing age, presence of diabetes, smoking, peripheral vascular disease, predialysis hypotension, and vessel characteristics, as directly influencing AVF patency. Vessels of small caliber (<2 mm) or demonstrating reduced distensibility are unlikely to create a functional AVF. Current evidence does not support altered patency due to sex or raised body mass index (<35 kg/m(2)). Factors such as early referral for AVF, preoperative ultrasound vessel mapping, use of vascular staples, and intraoperative flow measurements affected AVF patency, but the use of medical adjuvant therapies did not. Programs of surveillance and various needling techniques to maintain patency are not supported by current evidence. Novel techniques of infrared radiotherapy and topical glyceryl trinitrate are possible future strategies to increase AVF patency rates. The limitations of available evidence include a lack of large, randomized controlled trials and meta-analysis data to support current practice.

CONCLUSIONS

There is a complex interaction of factors that may affect the patency of an individual AVF. These need to be carefully considered when selecting surgical site or technique, adjuvant treatments, and follow-up protocols for AVFs.

Early follow-up results of arteriovenous fistulae created for hemodialysis

BACKGROUND

The aim of this study was to evaluate the site, early results, and postoperative complications of arteriovenous fistula (AVF) creation procedures for hemodialysis in our clinic.

METHODS

The hospital records of 384 patients who underwent 411 AVF creation procedures for hemodialysis by the same team at our clinic between February 2008 and January 2010 were included for retrospective analysis. All procedures were performed under local anesthesia with lidocaine. Vasospasm was treated by mechanical dilatation with a probe and topical papaverine.

RESULTS

Of our 384 patients, 58.5% were male and 41.5% were female. Mean age was 46 (range 12-72) years. Of the 411 AVF procedures performed, 106 (25.8%) were created at the anatomical snuffbox, 264 (64.3%) were Brescia-Cimino procedures, and 41 (9.9%) were antecubital, brachiocephalic, or brachiobasilic procedures. Twenty-three patients (5.98%) were subjected to more than one surgical intervention due to early thrombosis or failure of AVF. Early patency was found in 94.0% of the AVF created. Twenty-three patients underwent more than one surgical intervention due to early AVF thrombosis or failure. Early AVF failure occurred more often in females (60.8%) than in males (39.2%). Complications were observed in a total of 11.4% patients.

CONCLUSION

Mechanical dilatation of the artery and vein, before starting the anastomosis, as well as the use of vasodilatory agents, could decrease early thrombosis of the fistula, and this method has very high early patency.

Atrial fibrillation linked to vascular access thrombosis in chronic hemodialysis patients

AIM

Atrial fibrillation (AF) is characterized by the development of thromboembolic events and is more prevalent among end-stage renal disease patients than in the general population. Vascular access thrombosis (VAT) is a major morbidity in chronic hemodialysis (HD) patients; however, the association between AF and VAT is unknown.

METHODS

We retrospectively reviewed chronic HD patients with functional vascular access between 1997 and 2006. The association between AF and the development of VAT was analyzed using Kaplan-Meier analysis and multivariate Cox proportional hazards regression.

RESULTS

A total of 568 chronic HD patients, including 55 (9.7%) patients with AF, were reviewed and 154 (27.1%) patients developed at least one episode of VAT. Patients with AF had worse VAT-free survival than patients without AF (p< 0.001). In Cox regression, age, type of vascular access, atrial fibrillation, diabetes, hypertension, and C-reactive protein were independently linked to the development of VAT ( p= 0.049, < 0.001, < 0.001, 0.001, 0.028 and 0.045). The hazard ratios were 2.1 (95% CI: 1.00-1.03) for arteriovenous graft, 2.47 (95% CI: 1.66-3.69) for AF, 1.72 (95% CI: 1.25-2.39) for diabetes and 1.09 (95% CI: 1.00-1.18) for serum C-reactive protein (every 1 mg/dL increase), respectively.

CONCLUSION

Atrial fibrillaiton is linked to the development of vascular access thrombosis in chronic hemodialysis patients and is independent of traditional VAT risk factors.

Arteriovenous fistula as stable venous access in children with severe haemophilia

Treatment for children with severe haemophilia is based on prophylaxis and, if inhibitors occur, on immune tolerance induction (ITI). Both regimens require frequent infusions at early ages and therefore an adequate venous access is essential. Peripheral veins represent the best option; however, central venous catheters (CVCs) have been used to facilitate regular treatment. Unfortunately, survival of CVCs is affected by infectious and/or thrombotic complications that often lead to premature removal and consequent treatment discontinuation. This aspect may have an impact on treatment outcome, especially in the case of ITI. In light of this, internal arteriovenous fistula (AVF) has been proposed as an alternative option because of a lower rate of infectious complications. Moreover, AVF is easy to use in the home setting and is well accepted by children and parents. The possible complications are postoperative haematoma and transient symptoms of distal ischaemia; one case of symptomatic thrombosis has been reported to date. Other complications include loss of patency, aneurysmatic dilatation and limb dysmetria. A regular follow-up is mandatory to allow early remedial interventions. Surgical AVF dismantlement is recommended as soon as transition to peripheral vein access is possible.

The association between pulse pressure and vascular access thrombosis in chronic hemodialysis patients

Vascular access thrombosis (VAT) is a major cause of morbidity in chronic hemodialysis (HD) patients and is characterized by chronic inflammation. Pulse pressure (PP) is positively associated with chronic inflammation. Whether patients with high PP are at a higher risk for VAT, however, remains unknown. We retrospectively reviewed chronic HD patients with a functional vascular access point at the China Medical University Hospital between 1986 and 2005. The association between PP and the initial development of VAT at the primary vascular access point was examined using the Kaplan-Meier analysis and multivariate Cox proportional hazards regression. A total of 576 chronic HD patients (264 men and 312 women) with a mean age of 56.9+/-14.0 years were reviewed, of whom 145 (25.2%) experienced at least one episode of VAT. Patients with a PP>60 mm Hg had a lower VAT-free survival rate compared with those with a PP<60 mm Hg (P<0.001). Using Cox regression with adjustments for age, systolic blood pressure and vascular access types, PP (every increase of 10 mm Hg) and serum C-reactive protein (CRP) (every increase of 1 mg per 100 ml) were found to be independently associated with an increasing risk for VAT, with a hazard ratio of 2.57 (95% confidence interval: 1.5-4.4, P=0.001) and 1.14 (95% confidence interval: 1.01-1.27, P=0.017), respectively. High PP was associated with the development of VAT in chronic HD patients. This association was independent of serum CRP levels.

Benefits of Intraoperative Digital Subtraction Angiography in Primary Arteriovenous Fistula Creation

Digital subtraction angiography (DSA) is an ideal procedure for improving vascular surgery results, not yet in use for arteriovenous fistula (AVF) creation. In a prospective study, the practicability and benefits of intraoperative completion DSA (CDSA) for this purpose were investigated. When the arteriovenous anastomosis was completed and clinically judged as running, DSA via percutaneous or open-site puncture was conducted. Findings and consequences were prospectively documented. From July 2005 to September 2006 a primary AVF was created in 54 patients. Fifty of these could be included in the study (68, 39–91 yrs). In 44 a forearm fistula, and in six patients an elbow fistula was newly created. In two cases we were unable to insert a cannula into the A. brachialis (study escape). In the remaining 48 cases, CDSA visualized afferent artery, anastomosis and draining vein. No complications occurred associated with CDSA; 3.5, 2–12 ml, contrast agent were required per patient. In 13 cases, CDSA revealed problems with the AVF that could be corrected immediately: the vein was freed from restraining soft tissue (n=4), a stealing venous branch was ligated (n=6), transluminal thrombectomy was conducted (n=1) or anastomosis was newly created (n=3). AVF could be successfully created proven by ongoing dialysis in 30 cases, and in eight cases as demonstrated by clinical and sonographic evaluations, resulting in a primary 1-yr patency rate of 79.2%. CDSA in AVF surgery is practicable and reveals conditions that can be corrected immediately, thus improving surgical outcome. Long since standard in other areas of vascular surgery, CDSA should become a routine procedure in AVF creation.

Arteriovenous fistulas as vascular access for hemodialysis: The preliminary experience at the University Hospital of the West Indies, Jamaica

BACKGROUND

The demand for vascular hemodialysis access creation is steadily increasing. To satisfy the demand, a vascular access team was established at the University Hospital of the West Indies, Jamaica. The outcomes of this practice are reported.

METHODS

A retrospective study of all patients who had permanent vascular dialysis access established at the University Hospital of the West Indies between January 1, 2002, and December 31, 2006, was performed. Data were analyzed using SPSS version 12.0 (SPSS Inc, USA). A direct anastomosis between an autogenous artery and vein was considered an arteriovenous fistula (AVF). When prosthetic material was used, the access was considered to be an arteriovenous graft. Accesses that were nonfunctional after six weeks of maturation were considered to be primary failures, while those that failed after previous successful dialysis were considered to be secondary failures. Primary patency was defined as the interval between access placement and the first intervention for failure. Secondary patency was the interval between access placement and abandonment. Cumulative patency was defined as the number of accesses that remained patent over a given time period, regardless of the number of interventions performed.

RESULTS

Of 41 patients, nine were excluded due to incomplete data. Final analyses were performed on 32 patients with a mean (± SD) age of 42.3±15.3 years (range 18 to 66 years, median 43 years). The access type was an AVF in 100% of cases, which included distal radiocephalic fistulas in 27 patients, brachial-cephalic fistulas in three patients and proximal radiocephalic fistulas in two patients. Operations were performed in four (12.5%) incident and 28 (87.5%) prevalent dialysis patients. The mean delay between initiation of dialysis and AVF creation was 21.2±26.1 months (range one to 94 months, median 10 months). There were eight (25%) primary failures. Of the remaining 24 patients, there were seven (29.2%) secondary failures from thrombosis. There was primary patency for a mean of 723.9±422.1 days (range 199 to 1314 days, median 678 days). Only one (4.2%) patient had thrombectomy to prolong AVF function, resulting in secondary patency for 439 days. Cumulative patency was 62.5%, 33.3%, 25% and 4.2% for one, two, three and four years, respectively.

CONCLUSIONS

The rate of AVF creation for end-stage renal disease patients in this setting far exceeds the target goals set forward by the National Kidney Foundation published updated Dialysis Outcomes Quality Initiative (NKF/DOQI) Guidelines and the Centers for Medicaid & Medicare Services Fistula First initiative. This is being achieved with acceptable rates of morbidity and patency. There is room for improvement in postoperative surveillance to increase early detection of failing accesses and allow for increased utility of interventions for assisted patency.

Improved treatment feasibility in children with hemophilia using arteriovenous fistulae: the results after seven years of follow-up

BACKGROUND

An easy and stable venous access is essential in hemophilic children who receive regular prophylaxis or immune tolerance induction treatment. Central venous access devices improve treatment feasibility, but their use is complicated by infection and/or thrombosis. Arteriovenous fistula (AVF) has been evaluated as an alternative to central venous access devices in hemophilic children since 1999.

DESIGN AND METHODS

This study provides results obtained in a large series after seven years of follow-up.

RESULTS

From 1999 to 2008, 43 procedures were performed in 38 children (median age: 2.7 years). Thirty-five AVFs (81%) achieved maturation after a median of 58 days and were used for a median of five years (range: 0.4-8.5). A brachial artery caliber larger than 1.2 mm was associated with successful maturation (p<0.05). Complications with some impact on arteriovenous fistula use or duration were observed in 14/43 procedures (32%) and in 13/38 children (34%). Age at arteriovenous fistula creation was younger in children who lost arteriovenous fistula patency (p<0.05) and aneurysms were more frequent in children who were on daily treatment regimen and thus had a greater cumulative number of arteriovenous fistula accesses (p<0.05). At the end of the follow-up period, 22 AVFs were still in use and 9 had been surgically dismantled. Arteriovenous fistula use allowed long-term prophylaxis (up to 8.5 years) in 11 children and the completion of immune tolerance induction without interruptions in 18 children.

CONCLUSIONS

This study confirms the feasibility of arteriovenous fistula with an acceptable rate of complications and suggests that its use is particularly favorable in children with inhibitors in whom it should be considered as first-choice venous access.

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Does the surgeon's experience impact on radiocephalic fistula patency rates?

Establishing successful long-term hemodialysis access remains a major challenge. The primary aims of this study were to determine whether primary success and primary and secondary patency rates of a series of consecutive radio-cephalic fistulae (RCF) were affected by the experience of the surgeon. The secondary aims were to assess complications, and to compare results with patency rates from the literature. All native fistulae (AVF) created in our unit between January 1, 2002 and December 31, 2005 were analyzed retrospectively. The RCF were identified and divided into group A (RCF fashioned by the consultant surgeon), and group B (fashioned by the junior surgeons within the unit). Demographic characteristics, risk factors, primary success rate (patent fistula at discharge), and primary and secondary patency rates were compared between each group using chi-squared test. During this period, 552 AVF were created. Of the 195 RCF, there were 153 fistulae in group A and 42 in group B. Median follow-up was 22 months for both groups. There was no difference with regards to age, sex ratio, prevalence of diabetes, and cardiovascular disease. The primary success rate in group A and B was 94.2% and 81%, respectively (p < 0.01). Primary and secondary patency rates at 22 months were 80%, 93%* and 74%, 81%* in group A and B, respectively (*p < 0.025). Even within group B, these results compare very favorably with the published literature. These results suggest that the placement of a RCF should be performed by the most experienced member of a team dedicated to vascular access creation or at least under his supervision.

Evaluation of the efficacy of the transposed upper arm arteriovenous fistula: A single institutional review of 190 basilic and cephalic vein transposition procedures

INTRODUCTION

Although autogenous brachial-basilic upper arm transpositions (BVT) have been extensively utilized, there has been significant disparity in published patency rates. Very little is known about the efficacy of autogenous brachial-cephalic upper arm transpositions (CVT). We evaluated our experience with transposed upper arm arteriovenous fistulas (tAVF) in order to assess patency and identify factors that affect efficacy. We then compared our tAVF patients with a cohort of upper arm arteriovenous grafts (AVG).

METHODS

A retrospective review was conducted of tAVF performed at our institution from 1998 to 2004. The tAVF group consisted of 119 BVT and 71 CVT procedures. We compared these with 164 AVG. tAVF were placed only for veins >/=2.5 mm in diameter by duplex ultrasonography.

RESULTS

Mean follow-up was 28 months. With the exception of mean vein diameter, the patients in the BVT and CVT groups had similar demographic parameters and complication rates. Primary and secondary patency rates were 52% and 62% at 5 years for BVT and 40% and 46% at 5 years for CVT, respectively (P = NS). Multivariate analysis revealed that hemodialysis dependence at the time of fistula placement and history of previous upper arm access independently affected primary patency. History of upper torso dialysis catheters independently affected secondary patency. Comparison of the tAVF and AVG groups revealed that tAVF patients were significantly younger, more likely to be male, less likely to be African American (AA) and less likely to have a history of previous AV access. The primary patency rate for tAVF was significantly higher than for AVG: 48% vs 14% at 5 years (P < .001). The secondary patency rate for tAVF was also significantly higher than for AVG: 57% vs 17% at 5 years (P < .001). Among the tAVF procedures, 9% required one or more revisions to maintain secondary patency, compared to 51% with the AVG group (P < .001). Multivariate analysis revealed that presence of AVG and a history of previous upper arm access negatively affected primary and secondary patency.

CONCLUSIONS

Autogenous BVT and CVT have similar, high patency rates. Transposed upper arm arteriovenous fistulas have higher patency rates than upper arm AVG and require significantly fewer revisions. Our data strongly support the contention that as long as the patient is a candidate for an upper arm tAVF, based on anatomical criteria, a tAVF should always be considered before an AVG.