Comparison of autogenous fistula versus expanded polytetrafluoroethylene graft fistula for angioaccess in hemodialysis

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.

The decellularized vascular allograft as an experimental platform for developing a biocompatible small-diameter graft conduit in a rat surgical model

PURPOSE

The present study was aimed to assess the feasibility of using decellularized aortic allograft in a rat small animal surgical model for conducting small diameter vascular tissue engineering research.

MATERIALS AND METHODS

Decellularized aortic allografts were infra-renally implanted in 12 Sprague-Dawley (SD) adult rats. The conduits were harvested at 2 (n = 6) and 8 weeks (n = 6), and assessed by hematoxylin and eosin (H&E), van Gieson, Masson Trichrome staining, and immunohistochemistry for von Willebrand factor, CD 31(+), and actin.

RESULTS

Consistent, predictable, and reproducible results were produced by means of a standardized surgical procedure. All animals survived without major complications. Inflammatory immune reaction was minimal, and there was no evidence of aneurysmal degeneration or rupture of the decellularized vascular implants. However, the aortic wall appeared thinner and the elastic fibers in the medial layer showed decreased undulation compared to the normal aorta. There was also minimal cellular repopulation of the vascular media. The remodeling appeared progressive from 2 to 8 weeks with increased intimal thickening and accumulation of both collagen and cells staining for actin. Although the endothelial like cells appeared largely confluent at 8 weeks, they were not as concentrated in appearance as in the normal aorta.

CONCLUSION

The results showed the present rat animal model using decellularized vascular allograft implants to be a potentially durable and effective experimental platform for conducting further research on small diameter vascular tissue engineering.

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.

Duplex Scanning–Derived Access Volume Flow: Novel Predictor of Success Following Endovascular Repair of Failing or Nonmaturing Arteriovenous Fistulae for Hemodialysis

The objective of this study was to evaluate the feasibility of duplex scanning–derived access volume flow (DAVQ) to predict the success or failure of arteriovenous fistulae (AVF) after interventions. Eighty-eight DAVQ measurements were available for 60 AVF in 59 patients. In 25 cases, physical examination findings or inadequate dialysis suggested failing (11) or nonmaturing (14) AVF. Outflow stenoses (1–4; mean 1.2 ± 0.8) were confirmed by contrast fistulograms in 23 cases (17 peripheral; 6 central). These 23 cases underwent successful endovascular repair (17 balloon angioplasty; 6 stents) and had pre- and postintervention DAVQ measurements within 2 weeks of the procedure. Each was measured three times in a nontortuous venous segment with laminar flow, and mean values were used for comparison. The overall mean DAVQ for 65 functioning AVF was 1,199 ± 485 mL/min, whereas it was 652 ± 438 mL/min (range 150–1,840 mL/min) for the remaining 23 failing or nonmaturing cases ( p < .0001). Postintervention, the latter values changed to 867 ± 517 mL/min (range 257–2,020 mL/min), with a p < .13. Of these, 11 were still nonfunctional after endovascular procedures and had a mean DAVQ of 404 ± 111 mL/min (range 257–652 mL/min). The remaining 12 cases had a mean DAVQ of 1,280 ± 382 mL/min (range 762–2,020 mL/min) and were functional and usable for at least 6 months of follow-up ( p < .0001). It is interesting to note that none of the AVF cases with postintervention DAVQ < 700 mL/min became functional and usable, whereas all cases with a higher DAVQ underwent successful hemodialysis treatments. This early experience suggests that DAVQ can be used to predict the success or failure of an AVF following endovascular procedures. To our knowledge, this is the first such report.

Effectiveness of haemodialysis access with an autologous tissue-engineered vascular graft: a multicentre cohort study

BACKGROUND

Application of a tissue-engineered vascular graft for small-diameter vascular reconstruction has been a long awaited and much anticipated advance for vascular surgery. We report results after a minimum of 6 months of follow-up for the first ten patients implanted with a completely biological and autologous tissue-engineered vascular graft.

METHODS

Ten patients with end-stage renal disease who had been receiving haemodialysis through an access graft that had a high probability of failure, and had had at least one previous access failure, were enrolled from centres in Argentina and Poland between September, 2004, and April, 2007. Completely autologous tissue-engineered vascular grafts were grown in culture supplemented with bovine serum, implanted as arteriovenous shunts, and assessed for both mechanical stability during the safety phase (0-3 months) and effectiveness after haemodialysis was started.

FINDINGS

Three grafts failed within the safety phase, which is consistent with failure rates expected for this high-risk patient population. One patient was withdrawn from the study because of severe gastrointestinal bleeding shortly before implantation, and another died of unrelated causes during the safety period with a patent graft. The remaining five patients had grafts functioning for haemodialysis 6-20 months after implantation, and a total of 68 patient-months of patency. In these five patients, only one intervention (surgical correction) was needed to maintain secondary patency. Overall, primary patency was maintained in seven (78%) of the remaining nine patients 1 month after implantation and five (60%) of the remaining eight patients 6 months after implantation.

INTERPRETATION

Our proportion of primary patency in this high-risk cohort approaches Dialysis Outcomes Quality Initiative objectives (76% of patients 3 months after implantation) for arteriovenous fistulas, averaged across all patient populations.

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.

The natural history of autologous fistulas as first-time dialysis access in the KDOQI era

BACKGROUND

Patients on hemodialysis depend on durable, easily maintained vascular access. The autologous arteriovenous fistula (AVF) has been the gold standard since the introduction of the Brecia-Cimino fistula in 1966 and is echoed in the current Kidney Disease Outcomes and Quality Initiative (KDOQI) guidelines. The purpose of this study is to determine the natural history of AVF in patients requiring first-time permanent access in a large academic vascular surgery practice.

METHODS

We performed a retrospective review of patients undergoing new access creation from January 1, 2005 to June 30, 2005. The study group consisted of patients with no prior permanent access that underwent AVF creation. Categorical data was compared using chi2 analysis, nominal data was compared using Student t-test, and patency was determined by Kaplan-Meier curves.

RESULTS

During the 6-month period, there were 80 first time AVF creations. The majority of patients were male (69%), African American (55%), and a history of diabetes (55%) and hypertension (96%). Seventy-five percent of patients were already undergoing hemodialysis via catheter access. Seventy-six percent of patients underwent preoperative vein mapping with a mean vein diameter of 3.1 mm. Twenty-six radiocephalic AVF (RCAVF) and 54 brachiocephalic AVF (BCAVF) were created with a mean follow-up of 278 days. At the end of follow-up, 38 (48%) AVF were being used for hemodialysis and only nine (11%) matured without the need for additional intervention. Mean time for AVF maturation was 146 days. Thirty AVF (37%) were abandoned, 16 (20%) of which were primary failures. Mean time to abandonment was 162 days. Twelve (15%) AVF remained patent but were never cannulated. The intervention rate was 1.33 interventions/patient/year and 75% of interventions were percutaneous. Kaplan-Meier analysis determined primary, primary-assisted, and secondary patency was 36% +/- 8.3, 55% +/- 6.5, and 55% +/- 6.5 at 1 year, respectively. Cumulative functional patency was 63% at 1 year.

CONCLUSIONS

In patients receiving a first time permanent access, we found that the majority were AVF and they resulted in low primary patency rates at 1 year and long maturation times. KDOQI encourages AVF creation in order to increase AVF use for dialysis, but the strategy of simply increasing the number being created may not lead to the desired result and potentially lead to an increase in catheter dependence.

Surgical management of aneurismal dilation of vein and pseudoaneurysm complicating hemodialysis arteriovenuos fistula

BACKGROUND

Pseudoaneurysm (PS) and aneurismal dilation of vein (ADV) are recognized complications of arteriovenous fistulas (AVF) in patients on hemodialysis. We present our experience about surgical management of these complications, which resulted in AVF preservation for continuing hemodialysis.

MATERIAL AND METHODS

Twenty-two patients underwent surgical repair of an aneurismal dilation of vein or a pseudoaneurysm arising from a native AVF. In 14 patients the aneurismal dilation of vein arose from the venous limb of AVF and in eight patients the pseudoaneurysm arose from an arteriovenous anastomotic site in the antecubital and anterior part of arm. The mean follow-up period was 15 months. Clamp Aneurysm Repair (CAR) was performed to repair the aneurismal dilation of venous limb of AVF and Tourniquet Aneurysm Repair (TAR) was performed to repair PS that arose from AVF in the antecubital and anterior part of arm.

RESULTS

In eight of the 14 patients with aneurismal dilation of vein, who underwent CAR procedure, vascular access was preserved. In three patients with aneurismal dilation of vein in snuffbox and one in forearm, the AVF had failed due to prior venous thrombosis of AVF. In two of 14 patients, there was no need for preservation of AVF because of renal transplantation. The technical success rate and patency rate during follow up period in CAR method was 100%. In seven of eight patients with psudoaneurysm in the antecubital and anterior part of arm, who underwent TAR procedure, the AVF remained patent. The technical success rate in TAR method was 87.5%, and the patency rate was 87.5%. Overall, technical success rate was 95.45% and patency rate was 93.75%. During the 15 months of follow up period hemodialysis program through the repaired AVF sustained as desired.

CONCLUSIONS

The surgical methods used in our study could effectively repair the aneurismal dilation of vein and psudoaneurysm arising from a native AVF, and it lead to preservation of the AVF patency for continuing hemodialysis. These methods are technically feasible, safe and cost-effective procedures. It does not require dissection and additional incision for control of the vein and artery proximal and distal to the aneurismal dilation of vein and pseudoaneurysm; result in shorter time of procedure without complications.

Conduits for hemodialysis access

The role of prosthetic arteriovenous (AV) access is still important in the management and care of the renal dialysis patients. Multiple new modalities are available to the surgeon today and it is imperative that their role be understood so that optimum care can be delivered to this complex group of patients. This article describes significant changes in prosthetic management and newer configurations available to the surgeon.

Platelet Adhesion Testing May Predict Early Hemodialysis Arteriovenous Graft and Fistula Failure in End-Stage Renal Disease Patients

Vascular access thrombosis (VAT) is the most morbid and costly complication in end-stage renal disease (ESRD) patients. Although hypercoagulability is a major risk factor for VAT, in most patients, the cause of hypercoagulability cannot be identified despite clinical suspicion. In this study, platelet hyperreactivity was investigated for a possible role in the hypercoagulability of ESRD and VAT in 42 patients with arteriovenous (AV) grafts or fistulas. Platelet adhesion, platelet aggregation, and the history of VAT were assessed. The statistics included a nonparametric 2-factor ANOVA, a Mann-Whitney analysis, and a Kaplan-Meier analysis of hemodialysis angioaccess survival to examine platelet hyperadhesiveness as a predictor of access survival. The study showed a significant correlation between increased platelet adhesiveness and shortened survival of the primary hemodialysis angioaccess. Collagen-induced platelet aggregation reflected a significantly higher response in those with shortened access survival. These findings may have significant clinical implications for risk assessment and prevention of VAT.

Current techniques for assessment of upper extremity vasculature prior to hemodialysis vascular access creation

Vascular access problems lead to increased patient morbidity and mortality and place a large burden on care facilities, manpower and costs. Autogenous arteriovenous fistulas (AVF) are preferred over arteriovenous grafts (AVG) because of a lower incidence of vascular access related complications. An aggressive increase in the utilization of AVF, however, results in an increased incidence of AVF early failure and non-maturation. Increasing evidence suggests that routine preoperative assessment results in an increased utilization of functioning AVF by better selection of adequate vessels. To date, the reproducibility and standardization of assessment protocols are lacking and assessment of a single morphological parameter has not enabled adequate prediction of postoperative AVF function for individual patients. In this paper, we provide an overview of available diagnostic modalities and parameters that potentially enable better selection of adequate vessels for successful AVF creation.

Non-Surgical Salvage of Thrombosed Arterio-Venous Fistulae: A Case Series and Review of the Literature

Attempts to salvage thrombosed hemodialysis arterio-venous fistulae (AVF) using interventional techniques are not universally performed. Patients often require temporary dialysis catheters pending creation of a new vascular access. We determined the long-term outcome of interventional (non-surgical) repair of completely thrombosed AVF in 49 consecutive accesses (22 radio-cephalic, 1 radio-basilic, 19 brachio-cephalic, and 7 brachio-basilic) referred for an intervention within 48 hours of thrombosis. Subjects were 65% male (32), with mean +/- SD age 63.7 +/- 13.5 years (range 33-91), 51% African-American (25), 47% Caucasian (23) and 65% had diabetes (32). Overall, 96% (47/49) of thrombosed AVF were salvaged with complications observed in four cases (two extravasations of contrast; two radial artery emboli), with no serious long-term sequelae. Interventional procedures included 34 venous angioplasties, 11 venous angioplasties with stenting and two combined venous and arterial angioplasties. The primary and secondary patency rates for all salvaged AVF were 50.5 +/- 8.7%, 72.5 +/- 7.8% at 1 year, and 43.3 +/- 10%, 55.4 +/- 12.7% at 2 years, respectively. The median estimate to first intervention after the declot procedure was 14.7 months. The median estimate for continued function exceeded 23.1 months. There was no significant statistical difference in the primary (p = 0.73) and secondary patency rates (p = 0.057) for forearm vs. upper arm AVF. We conclude that interventional repairs should routinely be employed to salvage newly thrombosed AVF. The vast majority of these individuals can avoid receiving dialysis catheters or placement of a new dialysis vascular access.

The Value of Preoperative Vascular Imaging in the Selection and Success of Hemodialysis Access

The purpose of this study was to determine the value of preoperative vascular imaging (PVI) in the selection of an arteriovenous fistula (AVF) for hemodialysis with respect to site selection, maturation, patency, and functionality. We retrospectively evaluated 482 AVFs and arteriovenous grafts (AVGs) created in 321 patients who were regularly undergoing hemodialysis at our university's hemodialysis centers. The patients were divided into two groups according to PVI status. The patients in group 1 (n = 260) underwent Doppler ultrasonographic evaluation and venographic studies as well as physical examination before operation. The patients in group 2 (n = 222) underwent only physical examination before operation. Both groups were compared with respect to vascular access type, access maturation rate, and duration of access patency. In group 1, central veins were also evaluated for possible stenosis, and significant asymptomatic stenosis was treated with interventional techniques. The patients in group 1 were significantly older than those in group 2 and had a significantly higher mean number of previous central venous catheterizations and vascular access sites. At the initiation of the study, 234 of the vascular access sites had matured with a success rate of 90% in group 1. In group 2, however, 152 (68.5%) of the vascular access sites had matured. AVGs of the vascular access type were created in 31.5% of patients in group 1 and in 12.6% of patients in group 2. The mean duration of primary patency in group 1 overall (i.e., AVFs and AVGs) was 14.7 +/- 16.8 months, and the 6-month and 12-month patency rates were 72% and 46%, respectively. The mean duration of primary patency in group 2 overall was 11.9 +/- 9.4 months, and the 6-month and 12-month patency rates were 71% and 41%, respectively. Patients in group 1 had a significantly longer mean primary patency time than did those in group 2 (P = 0.024). Sixty-six cases of central vein stenosis were detected during PVI studies and treated interventionally. After those interventions, 38 AVFs and 28 AVGs were created, and all matured sufficiently without exception. As an adjunct to physical examination, PVI evaluations (venography, Doppler ultrasonography) can be used to determine the likelihood of the maturation of vascular access sites and can reveal problems such as central vein stenosis, which can then be treated promptly with percutaneous intervention. In patients with end-stage renal disease, these interventions should lead to a decrease in morbidity and mortality and improved quality of life.

The endless history of vascular access: a surgeon's perspective

Gaining access to blood circulation has been a major breakthrough of modern medical care and, despite the evolution of dialysis technology, vascular access (VA) remains the main impediment in providing quantity as well as quality of life to the end-stage renal disease (ESRD) patient. The external Scribner shunt and the internal Brescia/Cimino arteriovenous fistula (AVF) opened the way for further advancements such as graft angioaccess and other sophisticated devices. Forty years later, the radio-cephalic fistula remains the VA with the longest patency and the lowest complications. Although various technical solutions can be adopted for constructing access to the patient's vessels, the nephrologist must bear in mind that every VA in the upper limb, lower limb or body wall needs a run-in and a run-off: currently, thrombosis of the central vessels due to the excessive widespread use of central venous catheters (CVCs) emerge as a substantial cause of hemodialysis (HD) morbidity and mortality. Moreover, as there is a risk of central vein stenosis, even 2 weeks after catheter placement, and an impaired venous outflow precludes the creation of any VA and sometimes the placement of a kidney transplant in the iliac fossa for many years, we agree with McGill et al, who in 2005 said that ''expansion of catheter access may contribute to the reduced survival of hemodialysis patients in the United States''.

Pre-operative Radial Arterial Diameter Predicts Early Failure of Arteriovenous Fistula (AVF) for Haemodialysis

INTRODUCTION

Long term patency of arteriovenous fistula (AVF) is relevant to the management of end stage renal failure (ESRF) patients on haemodialysis (HD). We evaluated the role of routine radial arterial duplex for imaging radial artery before AVF formation to investigate the relationaship between radial artery internal diameter (ID) and AVF patency.

METHODS

21 patients with ESRF were examined by duplex sonography before AVF formation, 1 day, 1 week, 4 week and 12 weeks post AVF formation. For assessment of AVF patency, patients were divided into 2 groups. Group-1, 11 patients with radial artery ID <1.5mm and Group-2, 10 patients with radial artery ID >1.5mm. Measurement of radial artery blood inflow rate was calculated from mean blood flow velocity and vessel diameter. All AVFs were constructed on the forearm using autologous veins.

RESULTS

In Group-1, 5 patients (45%) showed immediate thrombosis of AVF graft. All patients in group-2 had patent AVF at 12 weeks. Pre-AVF formation radial artery blood inflow rate between two groups was not significantly different (p=0.06). Radial artery blood inflow rate was consistently and significantly higher in group-2 at all later time points with p value of <0.01 (Mann Whitney test).

CONCLUSION

There was a high failure rate of AVF with radial artery ID of <1.5mm. In the presence of small radial arteries primary access AVF in the upper arm should be considered.

Neutrophil dysfunction and infection risk in end-stage renal disease

Infections are still a major cause of morbidity and mortality in end-stage renal disease (ESRD) patients. The susceptibility of ESRD patients to infections is typically ascribed to the immunodeficient state associated with uremia. A central role in the host defense against bacterial infections is played by phagocytic polymorphonuclear white blood cells, which are characterized by the capacity to ingest and subsequently destroy bacteria. Disorders in polymorphonuclear cell function are exacerbated by the dialysis procedure and numerous factors including uremic toxins, iron overload, anemia of renal disease, and dialyzer bioincompatibility. It is concluded that the phagocytic defect observed in ESRD is multifactorial, and each factor should be managed individually with specific therapeutic approaches.

Risk Equation Determining Unsuccessful Cannulation Events and Failure to Maturation in Arteriovenous Fistulas (REDUCE FTM I)

Fistulas are the preferred permanent hemodialysis vascular access but a significant obstacle to increasing their prevalence is the fistula's high "failure to mature" (FTM) rate. This study aimed to (1) identify preoperative clinical characteristics that are predictive of fistula FTM and (2) use these predictive factors to develop and validate a scoring system to stratify the patient's risk for FTM. From a derivation set of 422 patients who had a first fistula created, a prediction rule was created using multivariate stepwise logistic regression. The model was internally validated using split-half cross-validation and bootstrapping techniques. A simple scoring system was derived and externally validated on 445 different, prospective patients who received a new fistula at five large North American dialysis centers. The clinical predictors that were associated with FTM were aged > or =65 yr (odds ratio [OR] 2.23; 95% confidence interval [CI] 1.25 to 3.96), peripheral vascular disease (OR 2.97; 95% CI 1.34 to 6.57), coronary artery disease (OR 2.83; 95% CI 1.60 to 5.00), and white race (OR 0.43; 95% CI 0.24 to 0.75). The resulting scoring system, which was externally validated in 445 patients, had four risk categories for fistula FTM: low (24%), moderate (34%), high (50%), and very high (69%; trend P < 0.0001). A preoperative, clinical prediction rule to determine fistulas that are likely to fail maturation was created and rigorously validated. It was found to be simple and easily reproducible and applied to predictive risk categories. These categories predicted risk of FTM to be 24, 34, 50, and 69% and are dependent on age, coronary artery disease, peripheral vascular disease, and race. The clinical utility of these risk categories in increasing rates of permanent accesses requires further clinical evaluation.

Clinical Course Associated with Vascular Access Type in a National Cohort of Adolescents Who Receive Hemodialysis: Findings from the Clinical Performance Measures and US Renal Data System Projects

Limited research has described clinical outcomes that are associated with the type of vascular access in pediatric patients who receive maintenance hemodialysis. This retrospective cohort study examined prevalent pediatric patients who were aged 12 to <18 yr and identified in the 2000 ESRD Clinical Performance Measures Project as receiving in-center hemodialysis. Vascular access type as of December 31, 1999, was identified. These patients were linked with 1 yr of data (January 1, 2000, through December 31, 2000) from US Renal Data System standard analytic files that allow for the comparison of rates of hospitalizations and access complications by access type. Of the 418 patients who met inclusion criteria, the mean age was 15.6 yr, 53% were male, 49% were white, the mean time on dialysis was 22 mo, and 42% had a structural/urologic cause of ESRD; 42% of patients had an arteriovenous graft or fistula, and 58% had a vascular catheter. Patients with a vascular catheter as compared with those with a graft or fistula had the following adjusted relative risks (95% confidence interval): 1.84 (1.38 to 2.44) for hospitalization for any cause, 4.74 (2.02 to 11.14) for hospitalization as a result of infection, and 2.72 (2.00 to 3.69) for a complication of vascular access. Vascular catheters are the predominant access type in adolescent patients who receive maintenance hemodialysis and are associated with significantly more hospitalizations and complications.

Ultrasonographic measurement of intima-media thickness of radial artery in pre-dialysis uraemic patients: comparison with histological examination

BACKGROUND

Increased intima-media thickness (IMT) of the radial artery is associated with early failure of radiocephalic arteriovenous fistula (AVF) in haemodialysis patients. Therefore, non-invasive measurements of radial artery IMT before AVF operations are very important in predicting AVF patency. This study was designed to evaluate the accuracy of high-resolution ultrasonography in measuring radial artery IMT in pre-dialysis uraemic patients.

METHODS

This study enrolled 43 pre-dialysis uraemic patients awaiting radiocephalic AVF operations for the first time. In this study, 17 age- and sex-matched uncomplicated hypertensive patients and 15 healthy subjects were included as a control. We measured the internal diameter (ID) and IMT of the radial artery using high-resolution ultrasonography on the wrists of uraemic patients as well as the control group before the AVF operation. We obtained specimens of the radial artery during the AVF operation and directly measured the IMT by histological examination.

RESULTS

The radial artery IMT of the uraemic patients (0.41 +/- 0.09 mm) was significantly thicker, compared to both those of the hypertensive (0.33 +/- 0.05 mm, P < 0.001) and the healthy patients (0.25 +/- 0.04 mm, P = 0.002). In contrast, the radial artery ID in the uraemic patients (1.85 +/- 0.48 mm) was smaller than both that of the hypertensive patients (2.08 +/- 0.31 mm, P = 0.023) and the healthy persons (2.34 +/- 0.37 mm, P = 0.001). Radial artery IMT had a negative correlation with radial artery ID in a total of 73 subjects (r = -0.290, P = 0.012). The value of the radial arterial IMT measured by sonographic examination correlated significantly with that by histological examination in 43 uraemic patients (r = 0.786, P < 0.001) and it correlated significantly with early AVF failure (r = 0.358, P = 0.027).

CONCLUSION

Our data suggest that high-resolution ultrasonography is an effective tool in measuring radial artery IMT in uraemic patients before AVF operation.

Autogenous radial-cephalic or prosthetic brachial-antecubital forearm loop AVF in patients with compromised vessels? A randomized, multicenter study of the patency of primary hemodialysis access

OBJECTIVE

The construction of an autogenous radial-cephalic direct wrist arteriovenous fistula (RCAVF) is the primary and best option for vascular access for hemodialysis. However, 10%-24% of RCAVFs thrombose directly after operation or do not function adequately due to failure of maturation. In case of poor arterial and/or poor venous vessels for anastomosis, the outcome of RCAVFs may be worse and an alternative vascular access is probably indicated. A prosthetic graft implant may be a second best option. Therefore, a randomized multicenter study comparing RCAVF with prosthetic (polytetrafluoroethylene [PTFE]) graft implantation in patients with poor vessels was performed.

METHODS

A total of 383 consecutive new patients needing primary vascular access were screened for enrollment in a prospective randomized study. According to defined vessel criteria from the preoperative duplex scanning, 140 patients were allocated to primary placement of an RCAVF and 61 patients to primary prosthetic graft implantation. The remaining 182 patients were randomized to receive either an RCAVF (n = 92) or prosthetic graft implant (n = 90). Patency rate was defined as the percentage of AVFs that functioned well after implantation.

RESULTS

Primary and assisted primary 1-year patencies were 33% +/- 5.3% vs 44% +/- 6.2% (P = .03) and 48% +/- 5.5% vs 63% +/- 5.9% (P = .035) for the RCAVF and prosthetic AVF, respectively. Secondary patencies were 52% +/- 5.5% vs 79% +/- 5.1% (P = .0001) for the RCAVF and prosthetic AVF, respectively. Patients with RCAVFs developed a total of 102 (1.19/patient-year [py]) vs 122 (1.45/py; P = .739) complications in the prosthetic AVFs. A total of 43 (0.50/py) interventions in the RCAVF group and 79 (0.94/py) in the prosthetic graft group were needed for access salvage (P = .077).

CONCLUSIONS

Although there were more interventions needed for access salvage in the patients with prosthetic graft implants, we may conclude that patients with poor forearm vessels do benefit from implantation of a prosthetic graft for vascular access.

Follow-up of polytetrafluoroethylene arteriovenous fistulae for haemodialysis

The polytetrafluoroethylene (PTFE) arteriovenous fistula allows vascular access for haemodialysis where a primary fistula or brachio-basilic vein transposition is not possible. We report patency rates and complications associated with these prosthetic grafts. Fifty-nine upper limb PTFE grafts in 48 patients were evaluated with a mean follow-up of 19 months (range 2-54 months). Three grafts (5%) were never used. The primary patency rate at 6 weeks was 90%. Cumulative secondary patency rates were 66% at 6 months, 36% at 12 months, 17% at 18 months, 3% at 24 months and 2% at 30 months. None of the grafts had remained patent at 3 years. Forty-six percent of the grafts studied thrombosed at least once and 32% became infected. Although the initial primary patency rate achieved compares favourably with that reported for brachio-basilic transposition fistulae, this study confirms that the use of prosthetic material is associated with a poor overall patency rate and high risk of complications. All options using autologous vein should be exhausted before considering prosthetic material.

Effect of intermittent compression of upper arm veins on forearm vessels in patients with end-stage renal disease

Native arteriovenous fistula is the best vascular access for chronic hemodialysis. Primary and long-term success depends, in part, on the state of arteries and veins at the time of the operation. The aim of our study was to investigate the effects of intermittent compression of upper arm veins on forearm vessels in patients with terminal renal disease. The study group was composed of 16 chronic hemodialysis patients who performed daily intermittent compression of the upper arm without vascular access by elastic band (Eschmarch). Ten chronic hemodialysis patients were included in the control group, which performed no specific activity. Forearm measurements were obtained at the beginning of the study and 4 and 8 weeks later during the course of intermittent compression of the upper arm veins. The forearm circumference and maximal handgrip strength were measured. The artery measures, including endothelium-dependent vasodilatation and forearm vein variables, were obtained by ultrasonography measurements. The forearm circumference, maximal handgrip strength, and artery variables, including endothelium-dependent vasodilatation, remained unchanged. The basal venous diameters (2.29 +/- 0.19 mm at the beginning, 2.46 +/- 0.19 mm after 4 weeks, and 2.53 +/- 0.18 mm after 8 weeks) were significantly increased in the study group. The distensibility of veins was preserved in the study group. There were no significant changes in the control group. Our study demonstrated that daily intermittent compression of the upper arm veins increases the forearm vein diameter and preserves the distensibility of veins in patients with end-stage renal failure.

Surgical Salvage of Thrombosed Arteriovenous Fistulas and Grafts

Our clinical experience with surgical salvage of thrombosed arteriovenous (AV) fistula and grafts, performed by a skilled interventional nephrologist is presented. A total of 286 surgical interventions were performed in 246 chronic hemodialysis patients aged 12-87 years (55 +/- 16 years), 268/286 (93.7%) in AV fistulas, 18/286 (6.3%) in grafts, and analyzed retrospectively. A subgroup of 61 procedures was analyzed prospectively. The type of procedure, immediate success and patency after surgery were evaluated. Thrombectomy with reanastomosis was performed in 197/286 (68.9%) and simple thrombectomy in 89/286 (31.1%) of the procedures. The time from thrombosis to surgery was 1-60 days (3.7 +/- 1.8). Immediate success was achieved in 258/286 (90.2%) of surgical procedures, 95.5% (189/198) in thrombectomies with reanastomosis, and 77.5% (69/89) in simple thrombectomies. Primary and secondary patency rates for AV fistulas after surgical salvage at 3, 6, 9, and 12 months were 93.1, 84.0, 78.3, 75.0% and 96.6, 88.0, 78.3, 77.3%, respectively. In order to maintain secondary patency, 1.15 surgical procedures per AV fistula were needed. The time to thrombosis in grafts was on average 10.2 months, primary and secondary functioning time from thrombectomy (until the end of observation period) was from 1 to 19 months (average 6.9 +/- 6.3 months) and from 5.5 to 19 months (average 9.1 +/- 5.6 months), respectively. In 7/16 (43.8%) surgical procedures, transluminal angioplasty and in 3/16 endovascular stent was placed after angioplasty. To maintain secondary patency, 2.3 surgical procedures per graft were needed. The surgical salvage of thrombosed AV fistulas and grafts, performed by a skilled interventional nephrologist, is successful in the short and long-term.

Hemodialysis vascular access: percutaneous interventions by nephrologists

Traditionally hemodialysis vascular access-related procedures have been almost exclusively performed by surgeons and interventional radiologists. In recent years, nephrologists have taken the initiative of performing these procedures themselves. Because of their unique clinical perspective on dialysis access and better understanding of the intricacies of renal replacement therapy, nephrologists are ideally suited for this activity. This approach has minimized delays, decreased hospitalizations, and decreased the use of temporary catheters, thereby improving medical care, decreasing costs, and increasing patient convenience. Vascular access-related procedures commonly performed by nephrologists include percutaneous balloon angioplasty, thrombectomy, and tunneled hemodialysis catheter-related procedures. In addition, using vein obliteration and percutaneous balloon angioplasty techniques, nephrologists have recently documented successful salvage of arteriovenous fistulas that had failed to mature, whereas traditionally these fistulas have frequently been abandoned. While the performance of these procedures by nephrologists offers many advantages, appropriate training in order to develop the necessary procedural skills is critical. Recent data have emphasized that a nephrologist can be successfully trained to become a competent interventionalist. In addition to documenting excellent outcome data, multiple reports have demonstrated the safety and success of interventional nephrology. This review focuses on hemodialysis access-related procedures performed by nephrologists and calls for a proactive approach in optimizing this aspect of patient care.

Influence of Intravenous Drug Abuse on Vascular Access Placement and Survival in HIV-Seropositive Patients

BACKGROUND

The influence of intravenous drug abuse (IVDA) on hemodialysis access placement practices and access survival in HIV-infected patients is unknown.

METHODS

We conducted a retrospective study of 60, HIV seropositive, maintenance hemodialysis patients. Type of access and assisted access survival (measured from date of placement) were compared in those with (77%) and without (23%) a history of IVDA.

RESULTS

Mean age was 37.8 years, mean baseline serum albumin was 2.9 g/dl and median CD4 count was 222 cells/mm3. Fifteen patients, all IVDA, were dialyzed using only tunneled catheters (median number of catheters per person (range): 2.5 (1-11)). There were longer delays in creation of a permanent access (p = 0.08), but no difference in the type of permanent access placed in IVDA versus the non-IVDA group. Over 1,051 cumulative months of access follow-up, 134 tunneled catheters, 28 grafts and 19 fistulae were placed, with observed failure rates of 1 per 4.7 access-months, 1 per 19.7 access-months, 1 per 38.2 access-months, respectively. The adjusted relative hazard of access failure for grafts versus catheters was 0.41 (95% CI: 0.23, 0.72; p = 0.002) and for fistulae versus catheters was 0.21 (95% CI: 0.08, 0.52; p = 0.001). Thirty-two percent of accesses were removed due to infection, an infection removal rate for catheters of 1 per 7.8 access-months and for grafts of 1 per 62.5 access-months; all graft infections occurred in the IVDA group. No fistula was removed due to infection.

CONCLUSION

Fistulae are the first line of choice for hemodialysis access in HIV-seropositive patients regardless of IVDA history; if not feasible, graft placement in non-IVDA or abstinent IVDA patients is recommended. In those with active IVDA, the optimal method of renal replacement therapy and type of hemodialysis access remain uncertain.

Midterm Results with the Use of Polycarbonate Urethane Heterografts for Dialysis Access

Dialysis access surgery is currently one of the most common vascular operations as the dialysis patient population increases. Although autogenous arteriovenous fistulae stand as the preferred method of access due to excellent patency and lower complication rates, grafts may provide alternative approaches when an autogenous fistula is impractical usually due to depleted veins. We aimed in this study to assess early and midterm outcome with the use of Expedial heterografts (LeMaitre Vascular Ltd., Wrexham, UK) for angioaccess between October 2000 and December 2004. Patients were prospectively followed for pre- and peri-operative course with 1st, 6th and 12th month outpatient controls for patency and complication rates. A total of 34 heterografts were implanted in 30 patients (22 males and 8 females; median age 60.6 years, range 32 - 70). The mean followup for 30 patients were 16.3 +/- 6.1 (range 4 - 30) months. 28 grafts (82.4%) were placed in forearm position. Primary and secondary patencies were found as 81% and 94%, respectively (p = 0.15), with the median censored primary and secondary patencies of 27 +/- 1.7 months (95% CI, 23.38 to 30.67) and 30.42 +/- 1.1 months (95% CI, 28.30 to 32.54), respectively. Only presence of diabetes was found as a significant risk factor in the regression model (p = 0.01). We suggest that the polycarbonate urethane heterografts with acceptable patency/complication rates and shorter maturation times for dialysis access serve an alternative for these patients.

Use of short PTFE segments (<6 cm) compares favorably with pure autologous repair in failing or thrombosed native arteriovenous fistulas

OBJECTIVE

The re-establishment of patency in a stenosed or thrombosed native arteriovenous fistula (AVF) is fundamental to regaining adequate hemodialysis through the same cannulable vein. Many surgeons have been reluctant to use even small segments of synthetic grafts in AVF revisions because of a perception that these would lead to poor results; however, studies comparing various treatment options are scarce. This study compared the use of short (<6 cm) polytetrafluoroethylene (PTFE) segments with pure autologous repair in stenosed or thrombosed native fistulas.

METHODS

The cumulative postintervention primary patency rates of two groups of hemodialysis patients receiving different surgical revision operations of their vascular accesses were prospectively compared. Group I (n = 30) comprised patients who presented with stenosed or thrombosed native fistulas and received short (2 to 6 cm) interposition PTFE grafts placed after the stenosed or thrombosed outflow vein segment was resected. These short PTFE grafts were not used for cannulation. Group II (n = 29) comprised patients who presented with dysfunctional or failed AVFs and underwent various types of pure autogenous corrections. AVF dysfunction or thrombosis was detected with clinical examination and color duplex ultrasound scanning. In all cases, on-table arteriography-fistulography was performed before surgical repair. Access adequacy was assessed in all patients postoperatively after the first puncture and every month thereafter (mean follow up 16.7 months).

RESULTS

No statistically significant difference in patency was observed between the two groups. Postintervention cumulative patencies were 100%, 88%, and 82% for group I and 90%, 82%, and 71% for group II at 6, 12, and 18 months, respectively ( P = .8).

CONCLUSIONS

Short (<6 cm) interposition PTFE segments used for the revision of failing or failed AVFs compare favorably to purely native repair and do not alter the autologous behavior of the initial access. These short PTFE revisions resulted in satisfactory midterm primary patency without further consumption of the venous capital by harvesting segments of vein from other locations and without compromising more proximal access sites. This practice is recommended and is justified as part of an aggressive access salvage policy addressed by many authors so far.

Radiocephalic wrist arteriovenous fistula for hemodialysis: meta-analysis indicates a high primary failure rate

OBJECTIVE

To improve the precision of the estimates of primary failure rates and primary and secondary 1 year patency of radial-cephalic arteriovenous fistulas (RCAVF) for hemodialysis.

DESIGN

Meta-analysis.

MATERIALS AND METHODS

A Medline search was performed of the English language medical literature between January 1970 and October 2002. Key words that were searched included radiocephalic fistula, arteriovenous shunt, Brescia-Cimino fistula and patency. Primary failure, primary and secondary patency rates were analysed using the standard mixed effects model, which allows for variability between the different studies.

RESULTS

Eight prospective and 30 retrospective studies were included. The analysis showed a pooled estimated primary failure rate of 15.3% (95% CI: 12.7-18.3%). In addition, the pooled estimated primary and secondary patency rates of 62.5% (95% CI: 54.0-70.3%) and 66.0% (95% CI: 58.2-73.0%), respectively, were calculated. Subgroup analysis concerning various study characteristics, including study year, gender and age, did not reveal statistically significant differences.

CONCLUSION

Although, the autogenous RCAVF is considered to be the primary choice for vascular access, this meta-analysis indicates a high primary failure rate and only moderate patency rates at 1 year of follow-up.

Healing of Implanted Expanded Polytetrafluoroethylene Vascular Access Grafts with Different Internodal Distances: A Histologic Study in Dogs

OBJECTIVE

We assessed characteristics of healing, over time, of two types of expanded polytetrafluoroethylene grafts.

STUDY DESIGN

An experimental histological study in dogs.

METHODS

The graft types studied had the same internal diameter (5 mm) but different internodal distances. In one, the internodal distance was 60 microm in the external surface and 20 microm in the luminal surface. In the other, the internodal distance was 30 microm throughout the material. Sixteen grafts of each type were implanted between the femoral artery and vein in 16 dogs; explanted 1, 2, 4 or 12 weeks later; and examined histologically.

RESULTS

In both graft types, infiltrating-cell density and maximum cell-penetration depth increased significantly between 1 and 2 weeks after implantation, but no significant increases occurred after 2 weeks. The number of inflammatory cells peaked 1 week after implantation and decreased significantly by 2 weeks. Subsequently, there were no significant changes in inflammatory cell numbers, suggesting that the inflammatory phase was over by 2 weeks after implantation and the grafts had become attached to surrounding tissue. There were no significant differences between the two graft types in cell density, cell-penetration depth, or number of inflammatory cells at any assessment time.

CONCLUSION

Our results provide histologic support for guidelines recommending that synthetic vascular grafts for hemodialysis access should not be cannulated until 2 weeks after implantation. Since increasing the internodal distance to 60 microm in the external surface had no effect on graft healing, methods other than manipulation of internodal distance should be used in developing a graft suitable for early cannulation.