Clinical epidemiology of arteriovenous fistula in 2007

The native arteriovenous fistula (AVF) is considered the best access for hemodialysis due to its longer survival and lower complication rates as compared with other forms of vascular access. However, broad practice variation exists in the use of AVF among different countries and even within the same country among different regions and centers. Several barriers to AVF placement have been identified in the last decade that might explain its suboptimal use among both prevalent and incident patients. The present review summarizes and discusses recent findings from epidemiological studies on practice patterns and risk factors for AVF failure. Special emphasis is devoted to drawbacks and payoffs consequent upon the choice of the AVF as access for dialysis. In fact the AVF requires major investments in the short run but far less assistance and rework thereafter. Primary AVF failure, due to early failure or lack of maturation, is currently considered a key area of investigation to improve vascular access outcomes. The main challenge for the nephrologist today is to minimize the risk of primary failure while attempting to provide most patients with a native AVF. Improving vascular access outcomes is clearly a complex and difficult task. Recent experience from the United States suggests that multidisciplinary management is the most appropriate approach to deal with all the multifaceted aspects of end-stage renal disease care and to increase the likelihood of success.     

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.     

Investigation of vascular access in maintenance hemodialysis patients in Shanxi province

Objective To understand the current situation of vascular access selection in maintenance hemodialysis (MHD) patients in Shanxi Province, and analyze the factors affecting vascular access selection and risk factors of death in MHD patients. Methods MHD patients with clear vascular access information in Shanxi Province from January 2014 to December 2018 were enrolled in this study. The clinical data of patients were collected. The vascular access information of the selected candidates was clear. Multivariate logistic regression equation method was used to analyze the influencing factors of vascular access and the risk factors of death in MHD patients. Results Among the 10.236 patients with MHD, 9.130 patients (89.2%) selected autologous arteriovenous fistula (AVF) as vascular access, and 5.138 patients (50.2%) chose tunnel-free and non-polyester sheath central venous catheter (NCC) for the first dialysis. Multivariate logistic regression analysis showed that the primary disease of diabetic nephropathy (OR=0.517, 95%CI 0.281-0.796, P＜0.001) and dialysis age＜1 year (OR=0.483, 95%CI 0.219-0.811, P＜0.001) were the influencing factors of patients with MHD who did not to choose AVF. Primary disease of diabetic nephropathy (OR=2.242, 95% CI 1.816-2.828, P＜0.001), and using of central vein catheter (OR=1.785, 95% CI 1.237-2.579, P＜0.001) were independent risk factors of death in MHD patients. Conclusions AVF is the first choice for MHD patients in Shanxi Province. There is higher proportion of the use of NCC as the first dialysis vascular access. Primary disease of diabetic nephropathy and dialysis age＜1 year are the influencing factors for MHD patients not to choose AVF. Primary disease of diabetic nephropathy and use of central vein catheter may increase the risk of death in MHD patients.     

Cardiovascular comorbidity and late referral impact arteriovenous fistula survival: a prospective multicenter study

Autologous arteriovenous fistulas (AVF) have the best 5-yr patency and the lowest complication rate among hemodialysis vascular accesses. However, maturation requirements to optimize survival are unknown. A longitudinal cohort study was conducted to ascertain risk factors for failure, maturation time, and survival of the first AVF. All patients who initiated hemodialysis between January 1, 1997, and December 31, 2002, in three centers were included in this study. Analysis was restricted to patients who received an AVF. Cox regression was used to estimate the association between predictors of interest and primary and secondary AVF survival. Of the 535 patients enrolled (mean age, 66.5 yr; 57.8% male; 26.7% diabetic), 513 (96%) received an AVF. Patients who initiated with catheters (47%) cannulated their AVF earlier (median maturation period, 0.78 versus 1.80 mo; P < 0.001). Median primary and secondary survivals were longer than 50 and 72 mo, respectively. After adjustment for confounding factors, cardiovascular disease (hazard ratio [HR], 1.84; 95% confidence interval [CI], 1.26 to 2.67), utilization earlier than 1 mo after placement (HR, 1.94; 95% CI, 1.34 to 2.82), and referral within 3 mo of dialysis start (HR, 1.55; 95% CI, 1.04 to 2.32) were associated with a reduction in primary AVF survival. Presence of cardiovascular disease (HR, 2.21; 95% CI, 1.38 to 3.55), maturation time <15 d (HR, 2.12; 95% CI, 1.20 to 3.73), and presence of catheters at hemodialysis initiation (HR, 1.79; 95% CI, 1.13 to 2.84) were associated with lower secondary AVF survival. It is concluded that cardiovascular disease, late referral, temporary catheters, and early cannulation are associated with impaired AVF survival. It is recommended that AVF be allowed to mature at least 1 mo before cannulation.     

Assessment of a policy to reduce placement of prosthetic hemodialysis access

BACKGROUND: The aim of this study was to evaluate the determinants of access patency and revision, including the effects of reducing the placement of prosthetic hemodialysis access. METHODS: A retrospective cohort study of all hemodialysis accesses placed at the Veteran's Administration Puget Sound Health Care System between 1992 and 1999 was conducted. A policy was instituted in 1996 that maximized the use of autogenous hemodialysis access. The impacts of the policy change, demographics, and comorbid factors on access type and patency, were examined. Primary and secondary patency rates were examined using the Kaplan--Meier method, and factors associated with failure and revision were examined using Cox proportional hazard models and Poisson regression. RESULTS: During the study, 104 accesses (61 prosthetic grafts and 43 autogenous fistulas) were placed prior to 1996, and 118 (31 prosthetic grafts and 87 autogenous fistulas) were placed after 1996. There was a significant increase in autogenous fistulas placed after 1996 (87 out of 118) compared with before 1996 (43 out of 104, P < 0.001). At one year, autogenous fistulas demonstrated superior primary patency (56 vs. 36%, P = 0.001) and secondary patency (72 vs. 58%, P = 0.003) compared with prosthetic grafts. After adjustment for age, race, side of access placement, and history of prior access placement, patients with a prosthetic graft were estimated to experience a 78% increase in the risk of primary access failure when compared with similar patients having an autogenous access [adjusted relative risk (aRR) = 1.78, 95% CI 1.21--2.62, P = 0.003)]. Similarly, the adjusted relative risk of secondary access failure for comparing prosthetic grafts with autogenous fistulas was estimated to be 2.21 (95% CI 1.38--3.54, P = 0.001). The adjusted risk of access revision was 2.89-fold higher for prosthetic grafts than for autogenous fistulas (95% CI 1.88--4.44, P < 0.001). CONCLUSIONS: Autogenous conduits demonstrated superior performance when compared with prosthetic grafts in terms of primary and secondary patency and number of revisions. A policy emphasizing the preferential placement of autogenous fistulas over prosthetic grafts may result in improved patency and a reduction in the number of procedures required to maintain dialysis access patency.     

Vascular access outcomes in the elderly hemodialysis population: A USRDS study

Arteriovenous fistulae (AVF) are widely regarded as the preferred vascular access in hemodialysis (HD) patients due to their primary patency and patient survival benefits. Recent scholarship has suggested that the elderly population differs significantly from the general population in terms of inflammatory markers. What is more, recent studies have suggested that the elderly HD population is less likely to have an AVF placed as the initial vascular access compared to a younger cohort. The purpose of this study is to investigate the applicability of current vascular access guidelines to the elderly HD population. We hypothesized that the elderly HD population would derive less patency and survival benefit from AVF placement relative to arteriovenous graft (AVG) than the general population is known to derive. We performed a retrospective analysis using the US Renal Data System (USRDS) Wave II dataset to explore significant predictors of referral for intervention or access failure, and patient survival in the elderly US HD population using Cox regression corrected for race, gender, peripheral vascular disease, diabetes mellitus, and nutritional status. Of the 1471 HD patients with AVF or AVG, 764 patients were >65 years. Elderly diabetics had no significant mortality benefit from the use of AVF compared to AVG [odds ratio (OR) 1.34 (95% CI 0.92-1.95), p = 0.123]. Likewise, elderly nondiabetics had no significant mortality benefit from the use of AVF compared to AVG [OR 1.05 (95% CI 0.81-1.36), p = 0.735]. Elderly diabetics had no difference in odds for intervention referral for AVF compared to AVG [OR 1.49 (95% CI 0.76-2.9), p = 0.24]. Elderly nondiabetics had no difference in odds for intervention referral for AVF compared to AVG [OR 1.48 (95% CI 0.95-2.3), p = 0.08]. We conclude that the potential benefits derived from AVFs compared with AVGs and central venous catheters (CVC) may not apply universally. The recommendations of vascular access choice stipulated by national guidelines may need to be modified for elderly patients.     

Veterans more likely to start hemodialysis with an arteriovenous fistula

Hemodialysis via arteriovenous fistulas (AVFs) is associated with reduced morbidity and mortality when compared to alternative vascular accesses, yet few patients in the United States start dialysis with AVFs. Recent studies have demonstrated higher quality of care for many conditions in Veterans Affairs' Medical Centers (VAMC); however, differences in quality of vascular access care are unknown. We used patient-level data (6/05-5/06) from Medicare claims (n = 25,912) to compare the proportions of AVF among incident patients at VAMC-affiliated (n = 20) and unaffiliated dialysis (n = 1631) facilities. Multivariate logistic regression was used to determine whether associations of access type with facility type were independent. Compared to non-VAMC patients, a larger proportion of VAMC patients started dialysis with AVFs (20.9% versus 11.6% in non-VAMC patients; OR 1.99, [95% CI 1.55-2.56]). Although attenuated, this finding persisted in models adjusted for demographics (OR 1.65 [95% CI 1.28-2.13]) and demographics with comorbidities (OR 1.70 [95% CI 1.31-2.20]). However, after accounting for pre end-stage renal disease (ESRD) care, similar proportions of VAMC and non-VAMC patients started hemodialysis with an AVF (OR 1.28 [95% CI 0.98-1.66]). In conclusion, patients receiving care at VAMC-associated facilities were more likely to start hemodialysis with AVFs, perhaps because of better pre-ESRD care. Nonetheless, AVF rates remain suboptimal, indicating a need for ongoing vascular access evaluation and improvement.     

A meta-analysis of the association between diabetic patients and AVF failure in dialysis

Purpose: The most preferable vascular access for patients with end-stage renal failure needing hemodialysis is native arteriovenous fistula (AVF) on account of its access longevity, patient morbidity, hospitalization costs, lower risks of infection and fewer incidence of thrombotic complications. Meanwhile, according to National Kidney Foundation (NKF)?Dialysis Out-comes Quality Initiative (DOQI) guidelines, AVF is more used than before. However, a significant percentage of AVF fails to support dialysis therapy due to lack of adequate maturity. Among all factors, the presence of diabetes mellitus was shown to be one of the risk factors for the development of vascular access failure by some authors. Therefore, this review evaluates the current evidence concerning the correlation of diabetes and AVF failure.

Methods: A search was conducted using MEDLINE, SCIENCE DIRECT, SPRINGER, WILEY-BLACKWELL, KARGER, EMbase, CNKI and WanFang Data from the establishment time of databases to January 2016. The analysis involved studies that contained subgroups of diabetic patients and compared their outcomes with those of non-diabetic adults. In total, 23 articles were retrieved and included in the review.

Results: The meta-analysis revealed a statistically significantly higher rate of AVF failure in diabetic patients compared with non-diabetic patients (OR?=?1.682; 95% CI, 1.429–1.981, Test of OR?=?1: z?=?6.25, p?<.001).

Conclusions: This review found an increased risk of AVF failure in diabetes patients. If confirmed by further prospective studies, preventive measure should be considered when planning AVF in diabetic patients.     

Arteriovenous Fistula Placement in the Elderly: When Is the Optimal Time?

Arteriovenous fistula (AVF) is the preferred vascular access for hemodialysis (HD). However, many AVFs fail before starting dialysis. To assess the optimal time for AVF placement in the elderly, we linked data from the US Renal Data System with Medicare claims data to identify 17,511 patients≥67 years old on incident HD who started dialysis between January 1, 2005, and December 31, 2008, with an AVF placed as the first predialysis access. AVF success was defined as dialysis initiation using the AVF, with time between AVF placement and dialysis start as our primary variable of interest. The mean age was 76.1±6.0 years, and 58.3% of subjects were men. Overall, 54.9% of subjects initiated dialysis using an AVF, and 45.1% of subjects used a catheter or graft. The success rate increased as time from AVF creation to HD initiation increased from 1–3 months (odds ratio [OR], 0.49; 95% confidence interval [95% CI], 0.44 to 0.53) to 3–6 months (OR, 0.93; 95% CI, 0.85 to 1.02) to 6–9 months (OR, 0.99; 95% CI, 0.88 to 1.11) but stabilized after that time. Furthermore, the number of interventional access procedures increased over time starting at 1–3 months, with a mean of 0.64 procedures/patient for AVFs created 6–9 months predialysis compared with 0.72 for AVFs created >12 months predialysis (P<0.001). Although limited by the observational nature of this study, our results suggest that placing an AVF>6–9 months predialysis in the elderly may not associate with a better AVF success rate.     

The Impact of Transvenous Cardiac Devices on Vascular Access Patency in Hemodialysis Patients

Creating a vascular access in the presence of a cardiovascular implantable electronic device (CIED) in a patient with or approaching end‐stage renal disease can be challenging. In this study, we aimed to evaluate the impact of a CIED on the outcomes of vascular access creation in hemodialysis patients and determine their effects on vascular access patency. This is a single‐center retrospective review of hemodialysis patients who underwent vascular access creation after CIED placement. Outcomes of vascular access creation and need for endovascular interventions were compared between patients with vascular access created ipsilateral and contralateral to the site of CIED. Comparing patients with arteriovenous (AV) access created ipsilateral to CIED placement (n = 19) versus the contralateral side (n = 17), the primary failure rate was 78.9% versus 35.3% (p = 0.02). For AV accesses that were matured, the median primary patency durations for AV accesses created ipsilateral to the CIED was 11.2 months compared to 7.8 months for AV accesses created contralateral to the CIED (p = 1.00). AV accesses created ipsilateral to a CIED have a higher primary failure rate compared with the contralateral arm and should be avoided as much as possible.     

A Meta‐analysis of Randomized Clinical Trials Assessing Hemodialysis Access Thrombosis Based on Access Flow Monitoring: Where Do We Stand?

The National Kidney Foundation Kidney Disease Outcomes Quality Initiative recommends the routine use of hemodialysis arteriovenous (AV) access surveillance to detect hemodynamically significant stenoses and appropriately correct them to reduce the incidence of thrombosis and to improve accesses patency rates. Access blood flow monitoring is considered as one of the preferred surveillance method for both AV fistulas (AVF) and AV grafts (AVG); however, published studies have reported conflicting results of its utility that led healthcare professionals to doubt the benefits of this surveillance method. We performed a meta‐analysis of the published randomized controlled trials (RCTs) of AV access surveillance using access blood flow monitoring. Our hypothesis was that access blood flow monitoring lowers the risk of AV access thrombosis and that the outcome differs between AVF and AVG. The estimated overall pooled risk ratio (RR) of thrombosis was 0.87 (95% confidence interval [CI], 0.67–1.13) favoring access blood flow monitoring. The pooled RR of thrombosis were 0.64 (95% CI, 0.41–1.01) and 1.06 (95% CI, 0.77–1.46) in the subgroups of only AVF and only AVG, respectively. Our results added to the uncertainty of access blood flow monitoring as a surveillance method of hemodialysis accesses.     

Accelerated increase of arteriovenous fistula use in haemodialysis centres: results of the multicentre CIMINO initiative.

BACKGROUND: In the Netherlands, arteriovenous fistulas (AVFs) are used in 60-65% of the haemodialysis patients and this compares poorly with the European average. A multicentre guidelines implementation programme, CIMINO, was initiated aiming at increasing the use of AVFs. METHODS: Physicians and dialysis staff in 11 participating centres (N=1092 vascular accesses) were strongly and repeatedly advised to adhere to current guidelines with extra attention for pre-operative duplex examination and salvaging of failing and failed fistulae. Specially appointed access nurses prospectively registered all created vascular accesses using an internet-linked database. In 22 other centres (N=1566 accesses), the CIMINO programme was not offered and they were considered the control group. RESULTS: On 1 January 2006, average follow-up time of the CIMINO group and the control group were 13.3 months and 34.1 months, respectively. A total of 598 new vascular accesses (77% AVFs) were created in the CIMINO group. Prevalent AVF use increased from 58.5% (range: 31-79%) to 62.7% (range: 45-83%) in the CIMINO group and from 65.5% (range: 31-91%) to 67.3% (range: 42-91%) in the control group. The increase in AVF use per year was significantly quicker than in the control group (P<0.05). Use of untunnelled catheters decreased whereas that of tunnelled catheters increased. CONCLUSIONS: This initiative shows that a multicentre guidelines implementation programme results in an accelerated increase of AVF use in comparison with a time control group. These data suggest that the choice of access placement depends predominantly on centre-specific factors.     

Impact of surgeon and surgical center characteristics on choice of permanent vascular access

BACKGROUND: The impact of the surgeon and surgical center characteristics on choice of autogenous arteriovenous (AV) fistula versus artificial AV graft as permanent vascular access for hemodialysis has not been studied. METHODS: We used national data from the Department of Veterans Affairs Veterans Health Administration to measure the association of surgeon and surgical center characteristics with choice of initial permanent vascular access among patients undergoing their first vascular access placement procedure between October 1, 2000 and September 30, 2001 (fiscal year 2001). Data were analyzed using a hierarchical logistic regression model clustered for surgical center and surgeon. RESULTS: The study population included 1114 patients, 74 Veterans Administration Medical Centers, and 182 surgeons. Seventy-two percent of patients received an AV fistula as their initial form of permanent vascular access. After adjusting for differences in patient, center, and surgeon characteristics, odds of AV fistula placement at high volume centers (>30 procedures per year) were more than three times greater than at low volume centers [odds ratio (OR) 3.26, 95% confidence interval (95% CI) 1.37 to 7.75, P = 0.008]. In addition, a strong clustering effect was present at the level of the surgeon (OR 1.55, 95% CI 1.19 to 2.03, P = 0.001) but not at the level of the surgical center, indicating an association with surgeon practice pattern. CONCLUSION: Barriers to AV fistula placement can exist at the levels of the surgeon and surgical center, respectively. Future strategies to improve AV fistula placement rates should target surgeons and surgical centers in addition to patients, nephrologists, and primary care providers.     

Superiority of Autogenous Arteriovenous Hemodialysis Access: Maintenance of Function with Fewer Secondary Interventions

The National Kidney Foundation Kidney Disease Outcomes Quality Initiative (NKF K/DOQI) guidelines have advocated autogenous arteriovenous fistulae as a primary procedure for hemodialysis access. This study compared the clinical outcomes between autogenous and prosthetic arteriovenous hemodialysis accesses, determining factors contributing to primary and secondary patency and function. Associated risk factors and number of interventions required to maintain secondary patency in each cohort were also assessed. A vascular database review of consecutive hemodialysis access procedures performed during a 36-month period (January 1999 to December 2001) at an academic institution was conducted. Life-table and log-rank analyses were used to analyze patency rates. Univariate and multivariate analysis was used to analyze risk factor influence on patency and function. A total of 231 upper extremity arteriovenous access procedures were performed in 209 patients during this period. One hundred autogenous accesses were created in 100 patients, 68 being forearm Brescia-Cimino arteriovenous fistulae. A total of 131 prosthetic accesses (ePTFE) grafts were also placed during this period in 109 patients. The demographic profiles of both cohorts were similar. Primary patency at 1 and 2 years was 56% (CI 45-76%) and 39% (CI 28-50%), respectively, in the autogenous group, and 36% (CI 26-45%) and 9% (CI 3-14%), respectively, in the prosthetic group. Differences in secondary patency at 1 year and 2 years were not significant (64% [CI 54-74%] and 53% [CI 42-65%] in the autogenous group vs. 65% [CI 55-73%] and 46% [CI 36-55%] in the prosthetic group). Secondary interventions were required in 87% of the prosthetic cohort (average 0.92 procedures/patient/year) and 57% of the autogenous cohort (average 0.53 procedures/patient/year). Multivariate analysis of associated risk factors demonstrated no significant effects on either primary or secondary patency in both groups. Autogenous accesses have superior primary patency and maintain equal secondary patency with significantly fewer interventions. These data strongly support the NKF K/DOQI guidelines recommending creation of autogenous access whenever possible. These outcomes can provide significant health-care cost benefits when using an algorithm favoring primary creation of autogenous access for hemodialysis. Presented at the Annual Meeting of the Southern California Vascular Surgery Society, Carlsbad, CA, April 11-13, 2003.     

Pre‐existing Arterial Micro‐Calcification Predicts Primary Unassisted Arteriovenous Fistula Failure in Incident Hemodialysis Patients

Vascular access micro‐calcification is a risk factor for cardiovascular morbidity and mortality in hemodialysis (HD) patients but its influence on vascular access patency is still undetermined. Our study aimed to determine the impact of arterial micro‐calcification (AMiC) on the patency of vascular access in HD patients. One‐hundred fourteen HD patients receiving arteriovenous fistula (AVF) operation were included in this study. During the operation, we obtained partial arterial specimen and performed pathological examination by von Kossa stain to identify AMiC. We compared primary unassisted AVF failure within 1 year between positive and negative AMiC groups, and performed Cox regression analysis for evaluating risk factor of AVF failure. The incidence of AMiC was 37.7% and AVF failure occurred in 45 patients (39.5%). The AVF failure rate within 1 year was greater in the positive AMiC group than those in the negative AMiC group (53.5% vs. 31.0%, p = 0.02). Kaplan–Meier analysis showed that the positive AMiC group had a lower AVF patency rate than the negative AMiC group (p = 0.02). The presence of AMiC was an independent risk factor for AVF failure. In conclusion, preexisting AMiC of the vascular access is associated with primary unassisted AVF failure in incident HD patients.     

Impact of ultrasonographic vascular mapping on constructing autogenous arteriovenous fistulas for permanent hemodialysis access?

PURPOSE: We used high resolution ultrasonography to identify usable veins and arteries in the forearm for creation of autogenous arteriovenous fistulas (AVF) for permanent hemodialysis access. The effect of preoperative vascular mapping followed by intraoperative controls on the outcome of AVF should be reported. METHODS: study subjects were adults referred for primary permanent hemodialysis access between January 2001 and November 2002. In all patients sonographic assessment was performed before surgical evaluation. A feeding artery was considered adequate if the diameter was more than 1.5 mm, the vein more than 2.0 mm. All AVF were controlled by intraoperative sonographic measurements of PSV and diameter of the fistula-vein. RESULTS: AVF were placed in 94.1% of all patients. The early failure rate of AVF was 6.3%. Primary patency rate of AVF after 24 hours: 93.7%, after 30 days: 91.4%, after 3 months: 86.9%, preliminary patency rate after 1 year: 70.1%. No unsuccessful surgical explorations were performed. 85.5 % of AVF were constructed as forearm fistulas. Suboptimal vessels (artery < 2.0 mm, vein < 3.0 mm) were used in 31.3% of patients. Patency rates did not differ in this subgroup. In 2 patients synthetic grafts were placed because of non-maturation of AVF. In 15 patients the AVF had to be cannulated by experts for 3 to 6 months. 50.0% of all AVF were constructed in diabetic patients. Patency rates were equal to that of non-diabetic patients. No patient suffered on signs of steal-syndrome. CONCLUSION: the assessment of forearm vessels by high resolution sonographic vascular mapping helps to find the optimal location for constructing an arteriovenous wrist fistula in almost all patients needing a permanent hemodialysis access. The aggressive approach to the creation of autogenous fistulas could be realized without unsuccessful surgical explorations and with a minimal early failure rate, a high maturation rate including patients with diabetes mellitus and no signs of steal-syndrome     

Remarks on Surgical Strategy in Creating Vascular Access for Hemodialysis: 18 Years of One Center’s Experience

The aim of the study is to evaluate surgical methods for creating vascular access for hemodialysis (HD) in patients with chronic renal failure. Over the last 18 years, 1,827 surgical procedures were performed in 722 patients (399 men and 323 women, mean age 43.7 ± 17 years) in order to provide and maintain permanent vascular access for HD. Among all the surgical procedures, 992 were based on the construction of arteriovenous fistulas (AVF) and 835 were undertaken as secondary reparative surgical procedures. A total of 992 vascular accesses have been performed, including 904 AVF on upper and 14 on lower extremities as well as insertion of 74 permanent catheters. Radiocephalic AVF (RCAVF) was the principal type of AVF (58.8%). While constructing secondary angio-access after using RCAVF on the other extremity, fistulas with usage of brachial vessels were preferred. A total of 228 AVF of this type were created, including 143 brachiocephalic (BCAVF) and 85 brachiobasilic (BBAVF) AVF. Lately, synthetic grafts (arteriovenous graft, AVG) have been used more frequently, in 90 AVF. A brachial straight graft was the main type procedure performed, with polytetrafluoroethylene (95.6%). The patency of the fistulas has been evaluated. Kaplan-Meier survival curves were calculated to determine primary, primary-assisted, and secondary patency. Log-rank analysis was used to determine differences between curves. Primary, primary-assisted, and secondary patency at 12 months and 24 months were calculated. Comparing AVF patency in two patients’ age periods (18-65 years, >65 years), it may be concluded that in the elderly group AVG provides better treatment for AVF. Finally, we conclude that a multidisciplinary approach to vascular access strategy offers the best option to achieve good functional AVF. Autogenous arteriovenous access should be regarded as the most suitable type in creating VA. However, individual conditions should be taken into consideration.This work was published in part in abstract form (3rd International Congress of the Vascular Access Society, Lisbon, Portugal, 2003).     

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.     

A multicenter study of permanent hemodialysis access patency: beneficial effect of clipped vascular anastomotic technique

OBJECTIVE: There is an urgent and compelling need to reduce the morbidity and expense of maintaining hemodialysis vascular access patency. This large, long-term, retrospective, multicenter study, which compared access patency of autogenous arteriovenous fistulas (AVF) and synthetic bridge grafts (AVG) created with conventional sutures or nonpenetrating clips, was undertaken to resolve conflicting results from previous smaller studies. DESIGN: Patency data for 1385 vascular access anastomoses (clipped or sutured) was obtained from 17 hospitals and dialysis centers (Appendix). Five hundred eighteen AVF (242 clip, 276 suture) and 827 AVG (440 clip, 384 suture) were analyzed. Statistical comparisons were made with Kaplan-Meier survival analysis, log-rank test, two-sample t test, and X(2) test. The Cox proportional hazards model was used to confirm Kaplan-Meier analysis. RESULTS: Access patency (primary, secondary, overall, and intention to treat) was significantly improved in access anastomoses constructed with clips. In the intention-to-treat group, primary patency at 24 months was 0.54 for clipped AVF and 0.34 for sutured AVF, and was 0.36 for clipped AVG and 0.17 for sutured AVG. At 24 months, primary patency rate for AVF successfully used for dialysis was 0.67 for clips and 0.48 for sutures, and for AVG was 0.39 for clips and 0.19 for sutured constructs. Interventions necessary to maintain patency were significantly fewer in clipped anastomoses. CONCLUSION: Replacing conventional suture with clips significantly reduces morbidity associated with maintaining permanent hemodialysis vascular access. This beneficial effect may be due to the biologic superiority of interrupted, nonpenetrating vascular anastomoses.     

Conversion of tunneled hemodialysis catheter-consigned patients to arteriovenous fistula

OBJECTIVE: Despite their high incidence of complications, costs, morbidity, and mortality, nearly 27% of the chronic hemodialysis (HD) patients are receiving treatment via a tunneled hemodialysis catheter (TDC). METHODS: In this prospective analysis, an interventional nephrology team employed an organized program consisting of vascular access (VA) education and vascular mapping (VM) to TDC-consigned patients. A full range of surgical approaches for arteriovenous fistula (AVF) creation, including vein transpositions, was exercised. Physical examination was performed every 1 to 2 weeks after surgery to assess the development of the AVF. Fistulas that failed to develop adequately to support HD (early failure) underwent salvage [percutaneous transluminal angioplasty (PTA), accessory vein obliteration (AVL)] procedures. RESULTS: One hundred twenty-one TDC-consigned patients received VA education. Eighty-six (71%) agreed to undergo VM. Two groups were identified. Group I (N= 66; using TDC for 7.2 +/- 1.8 SD months) had never had an arteriovenous access; group II (N= 20; using TDC for 12.3 +/- 4.0 months) had a history of one or more previously failed arteriovenous accesses. Upon VM, 64/66 (97%) in group I and 18/20 (90%) in group II were found to have adequate veins for AVF creation. Seven patients (11%) in group I and 3 (17%) in group II refused surgery. In group I, 57 (89%) received an arteriovenous access (radiocephalic AVF = 15, brachiocephalic AVF = 35, transposed brachiobasilic AVF = 3, brachiobasilic AVG = 4). In group II, 15 (83%) received a transposed AVF (radiobasilic = 2, brachiobasilic = 13). Sixteen fistulas (30%) in group I and 8 (53%) in group II had early failure. All except for one fistula in each group were salvaged using PTA and/or AVL. All 70 accesses (AVF = 66, AVG = 4) remain functional, with a mean follow-up of 8.5 +/- 3.6 months. CONCLUSION: These results demonstrate that an organized approach based upon a comprehensive program utilizing VA counseling, VM, application of full range of surgical techniques, and salvage procedures can be very successful in providing optimum vascular access to the catheter-dependent patient.