Vascular access outcomes and medication use: a USRDS study

Several medications have been proposed to improve hemodialysis (HD) vascular access outcomes based on potentially favorable anticoagulant, antiplatelet, or pleiotropic properties. The purpose of this study was to evaluate the relationship between medication use and vascular access patency in a group of HD patients. We conducted a historical cohort study of the US Renal Data System Dialysis Mortality and Morbidity Wave II study to identify patients with an arteriovenous fistula (AVF), polytetrafluoroethylene (PTFE) graft, or a permanent catheter for vascular access. Cox regression analysis, adjusted for age, gender, race, history of coronary artery disease, peripheral vascular disease, or coronary artery bypass graft, was used to model the hazard ratio (HR) of permanent vascular access failure. Of the 2001 HD patients in the Wave II study, 901 (45%) were included in the analysis. PTFE graft patency was greater for males (HR, 0.73; 95% CI 0.53-1.00, p = 0.05) and for older individuals (HR, 0.99; 95% CI 0.98-1.00, p = 0.02). Treatment with antiplatelet medications, ticlopidine and dipyridamole (HR, 3.54; 95% CI 1.07-11.76; p = 0.04), or aspirin (HR, 2.49; 95% CI 1.31-4.73; p = 0.005) was associated with significantly worse AVF patency. Antiplatelet agents had a significant negative association with access patency in this cohort. In contrast to other published data, it was difficult to identify any beneficial effect of specific medications on access patency.     

Vascular access for hemodialysis in the elderly

Objective

The objective of this study was to compare the outcomes of arteriovenous fistulas (AVFs) with arteriovenous grafts (AVGs) in a large population-based cohort of elderly patients in the United States.

Vascular access for hemodialysis: A perpetual challenge

Vascular access for hemodialysis has a long and rich history. This article highlights major innovations and milestones in the history of angioaccess for hemodialysis. Advances in achievement of lasting hemodialysis access, swift access transition, immediate and sustaining access to vascular space built the momentum at different turning points of access history and shaped the current practice of vascular access strategy. In the present era, absent of large‐scale clinical trials to validate practice, the ever‐changing demographic and comorbidity makeup of the dialysis population pushes against stereotypical angioaccess goals. The future of hemodialysis vascular access would benefit from proper randomized clinical trials and acclimatization to clinical contexts.     

Vascular access and patient outcomes in hemodialysis: questions answered in recent literature

Hemodialysis is not possible without access to the vascular system to provide an adequate and reliable source of blood flow through the hemodialyzer. Since maintenance hemodialysis therapy became a reality in the latter half of the twentieth century, no vascular access has exceeded the success and reliability of arteriovenous fistulae (AVF). They have the lowest infection and thrombosis rates, have the longest patency rates, and are associated with the best morbidity and mortality outcomes of any access modality. In the United States, the majority of patients starting hemodialysis do not have a primary AVF, which may explain why vascular access complications represent almost 20% of the total spending for hemodialysis. In addition, as much as 50% of hospitalization costs for end-stage renal disease are related to access issues. Every effort must be directed in the U.S. as well as elsewhere to promote the use of AVF whenever possible. In some European countries, more than 90% of patients have AVF as their hemodialysis access when nephrologists perform placement of vascular access. Already, some programs in the U.S. have recognized the need for trained nephrologists to provide these services. U.S. interventional nephrologists should be given the opportunity to learn AVF placement procedures to emulate their European counterparts, and thus improve U.S. dialysis outcomes.     

Vascular access for hemodialysis

A well-functioning vascular access for hemodialysis plays a key role in the quality of life and clinical outcome of dialysis patients. A vascular access for dialysis is considered to be adequate when it provides a blood flow of at least 250 ml/min in the standard dialysis and up to 350-400 ml/min in the high-efficiency dialysis. So far, Cimino-Brescia arterio-venous fistula still remains the gold standard among the available vascular accesses. It should be the first-choice vascular access. Unfortunately, due to the growing age of patients requiring dialysis, to the late-referral phenomenon, to the poor forearm vascular district, and to the increase in acute forms of renal disease, the use of vascular prostheses and central venous catheter becomes more and more frequent. The most important complications of vascular access are stenoses, thromboses, infections. Infections, more frequent in synthetic vascular access than in native fistulas, are responsible for the increase in patients' morbidity and, consequently, in public health costs. An integrated multi-professional approach of vascular access, involving nephrologists, vascular surgeons, interventional radiologists, and trained dialysis nurses should be implemented in order to early detect vascular access complications and failure.     

Vascular access for hemodialysis

Establishing and maintaining adequate vascular access is essential to providing an appropriate dialysis dose in patients with end-stage renal disease. Complications related to vascular access have a significant role in dialysis-related morbidity and mortality. The National Kidney Foundation Kidney Disease Outcomes Quality Initiative (K/DOQI) clinical practice guideline for dialysis access was last updated in 2000 and provides a framework for the optimal establishment and maintenance of dialysis access, and treatment of complications related to dialysis access. This paper reviews the 2000 K/DOQI dialysis access guideline as well as updated information published subsequently.     

Obesity as a predictor of vascular access outcomes: analysis of the USRDS DMMS Wave II study

Arteriovenous fistulae (AVF) are widely regarded as the preferred vascular access in hemodialysis patients due to their primary patency and patient survival benefits. While the obesity paradox has been associated with improved cardiovascular morbidity and all-cause mortality in dialysis patients, its long-term vascular access outcomes are less clear. Recent literature has suggested that obese patients may have increased early and late fistula failure. The purpose of this study was to explore the relationships between obesity and vascular access outcomes. We performed a retrospective cohort analysis using the USRDS DMMS Wave 2 data set. All incident dialysis patients as of January 1, 1996, over the age of 18, receiving only hemodialysis as mode of renal replacement therapy were eligible for inclusion. Among other variables, data collected for the DMMS Wave 2 included: type and location of vascular access, AVF maturity, vascular access revision, and failure. Logistic regression analyses were used to examine the relationships between obesity and vascular access outcomes, adjusting for important covariates. In all, 1486 hemodialysis patients were included. Using body mass index (BMI) <30 kg/m(2) as reference, obesity did not emerge as a factor in predicting vascular access revisions or failures. An increased risk of AVF failure to mature was found only in the highest BMI quartile (>or=35 kg/m(2)) (aOR 3.66 [95% CI 1.27-10.55], p = 0.017). Peripheral vascular disease was independently associated with an increased risk of AVF failure (aOR 2.78 [95% CI 1.01-7.63], p = 0.047) and arteriovenous graft (AVG) failure (aOR 1.65 [95% CI 1.03-2.64], p = 0.036). Obesity was not associated with increased AVF or AVG revision rates or failure and only associated with poorer AVF maturity at highest BMI quartile. We conclude that obesity should not preclude placement of AVF as vascular access of choice, except in the very obese where assessment should be individually based.     

Vascular access for hemodialysis in children

In the light of many years’ experience in hemodialysis access surgery, the different methods of creating vascular access for dialysis treatment in the pediatric population are described. After presenting the various access types using autologous blood vessels and also heterologous grafts, their specific spectrum of complications is discussed in detail. Summarizing our experience it has to be emphasized that there is no specific angioaccess for children and adolescents, and that most vascular access procedures used in adults are also suitable for use in the young. Received June 17, 1996; received in revised form July 29, 1996; accepted July 30, 1996     

Variations in outcomes of hemodialysis vascular access by race/ethnicity in the elderly

Objective

Prevalence of end-stage renal disease, modality of treatment, and type of hemodialysis vascular access used varies widely by race/ethnicity in the United States, but outcomes of hemodialysis vascular access by race/ethnicity are poorly described. The objective of this study is to evaluate variations in outcomes of hemodialysis vascular access in the elderly by race/ethnicity.

Vascular access for hemodialysis: 2004 and beyond

PURPOSE OF REVIEW: Developments in vascular access are accruing rapidly. The last systematic Kidney Disease Outcomes Quality Initiative guidelines review took place in 2000. The purpose of this review is to update several major areas in which clear progress has been made. A major 'Fistula First Initiative' in the USA is an attempt to increase markedly the fraction of patients receiving an autologous arteriovenous fistula as opposed to a graft. Preoperative mapping to evaluate veins and artery may permit construction of arteriovenous fistula in up to 70% of all patients, thereby reducing access thrombosis, infection, and perhaps increasing survival of patients. RECENT FINDINGS: Although a number of different synthetic materials have been tried, none seems to have any definite advantage over plain expanded polytetrafluoroethylene for constructing synthetic bridge grafts. Two developments may influence practice: use of composite self-sealing grafts that can be used within hours may eliminate the need for temporary catheters; and use of nitinol surgical clips may reduce endothelial trauma and improve patency. Large-bore catheters can deliver blood flows of over 400 ml/min initially, but they are prone to progressive occlusion. Optimal means of using a fibrinolytic to preserve flow must be evaluated. Surveillance techniques are undergoing rapid re-evaluation. Finally, a variety of antibiotic lock techniques are being evaluated for their ability to prevent catheter-related infections. SUMMARY: Greater efforts must be made to establish pre-end-stage renal disease programs to educate and prepare patients for hemodialysis and improve arteriovenous fistula placement rates, and to encourage clinicians to re-examine their current clinical practices and dedicate themselves to improving vascular access outcomes.     

Vascular access for dialysis in the elderly

Although not taken in consideration as aspecial issue in current guidelines, vascularaccess in the elderly deserve specificrecommendations as they are quickly enlargingas a group, with particularly high vascularaccess morbidity and failure rate.Hemodynamic and endothelial mechanisms ofaccess failure are reviewed and tentativestrategies to increase the prevalence ofdurable native arteriovenous fistulas areanalysed.     

Vascular access for hemodialysis: an indepth review.

A multi-disciplinary approach to vascular access planning, early preoperative surgical assessment and increased use of vascular imaging for surveillance, specialist service and pharmacological prevention of intimal hyperplasia will lead to improved patency rates for both autologous AVF and synthetic grafts.     

Vascular access complications in long-term pediatric hemodialysis patients

Current data demonstrate pediatric patients who remain on hemodialysis (HD) therapy are more likely to be dialyzed via central venous catheters (CVCs) than arteriovenous grafts (AVGs) and fistulae (AVFs). We retrospectively compared complications and health-related quality of life (HRQOL) associated with different vascular access types at two large centers over a 1-year period. Patients included in the study were younger than 25 years of age, weighed >20 kg, and had received HD for at least 3 months. Thirty CVC patients and 21 AVG/AVF patients received a total of 2,393 and 3,506 HD treatments, respectively. The infectious complication rate was higher for CVC patients, who were hospitalized 3.7 days for each 100 HD treatments versus 0.2 days for AVG/AVF patients (p < 0.01). CVC patients also had a much higher rate of access revision, needing 2.7 hospital days every 100 HD treatments compared with 0.2 days for AVG/AVF patients (p < 0.01). HRQOL scores did not differ between groups. Thus, despite similar HRQOL, CVCs were associated with more complications and greater morbidity when compared with AVG/AVFs. These findings further emphasize the need to use AVG/AVFs as primary HD access for pediatric patients expected to receive a long course of maintenance HD.     

Vascular access calcification predicts mortality in hemodialysis patients

Vascular calcification is a recognized risk factor for cardiovascular mortality in patients with end-stage renal disease. The aim of this study was to identify risk factors for vascular access calcification and to determine if patients with this disorder are at increased risk of death. Vascular access calcification was found in 49 of 212 hemodialysis patients as measured by plain X-ray (arteriovenous fistula or synthetic graft) in two dimensions. Male gender, diabetes mellitus, and length of time on dialysis were independent predictors for access calcification determined by logistic regression multivariate analysis. Serum parameters were not independently related to access calcification. Kaplan-Meier analysis showed an increased mortality risk, and Cox regression analysis confirmed that vascular access calcification was an independent mortality predictor. Our study suggests that detection of vascular access calcification is a cost-effective method to identify patients at increased mortality risk.     

Vascular access for chronic hemodialysis in diabetic patients

The aim of this study carried out on 33 uremic diabetic patients submitted to chronic hemodialytic treatment was to assess the kind of complications related to the vascular approach used as well as their short- and long-term incidences. Out of the 46 anastomoses prepared, 39 were arteriovenous fistulae according to Brescia-Cimino and 7 were PTFE grafts. The actuarial survival rate was 88%, 79%, and 63% after one, two and four years, respectively. The most frequent compliance was thrombosis. Our experience demonstrates that the distal arteriovenous fistula may be considered a valid vascular access for hemodialysis also in diabetic patients.