Survival of prosthetic grafts of different materials after impairment of a native arteriovenous fistula in hemodialysis patients

Challenges of Hemodialysis Access for High Risk Patients: Impact of Mesenteric Vein Bioprosthetic Graft

Objective

The purpose of this study is to compare in a prospective fashion the performance of a new bioprosthesis, the mesenteric vein bioprosthesis (MVB), in patients who have had multiple failed ePTFE grafts. Performance measures include primary patency rates, assisted-primary patency rates, secondary patency rates, complications, and the number of interventions required to maintain graft patency. Study: From October 1999 to February 2002, 276 hemodialysis access grafts were implanted in a multicenter study. Of those grafts, 74 were placed in patients with a prior history of ≥ 3 failed prosthetic grafts (mean = 3.5 grafts, range = 3–6 grafts). Fifty-nine grafts were constructed with MVB, and 15 grafts with ePTFE as a concomitant control. Mean follow-up was 11.5 months. In the MVB group, 79.7% were African-Americans, 61% were females, and 23.7% were hypercoagulable. Of the ePTFE group, 86.7% were African-Americans, 46.7% were female, and 13.2% were hypercoagulable.

Results

Per Kaplan-Meier curves, the primary patency rate of the MVB group at 12 months was 33% vs the ePTFE group of 18% (p=0.120); the assisted-primary patency rates at 12 months were 45% MVB vs 18% ePTFE (p=0.011). The secondary patency rates at 12 and 24 months for the MVB group were 67% and 59%, respectively, vs 45% and 15% for the ePTFE group (p=0.006). During the follow-up time period, 80% of the ePTFE grafts were abandoned compared to 34% of the MVB group. Infection and thrombosis rates in the MVB group were lower than the ePTFE group. The infection rate for the MVB group requiring intervention was 0.07 events/graft year (gt/y) compared to 0.30 events/gt-y for ePTFE (p=0.04). A thrombosis rate of 0.69 events/gt-y occurred in the MVB group whereas 2.50 events/gt-y presented in the ePTFE group (p<0.01). Conclusion: In this study, high-risk patients (defined as those having multiple failed prosthetic grafts for hemodialysis) in whom the MVB conduit for hemoaccess was implanted, showed significant improvement in assisted-primary and secondary patency rates compared to the ePTFE cohort. The MVB group, however, did not have a statistically better primary patency rate compared to the ePTFE group. The MVB patient also had fewer thrombotic and infectious events and an overall reduction in the number of interventions while maintaining a permanent access site. This new bioprosthesis should be the conduit of choice in the complex group of patients as it offers assisted-primary and secondary patency rates similar to those commonly experienced by patients without a history of multiple graft failures.

Polytetrafluoroethylene and Bovine Mesenterial Vein Grafts for Hemodialysis Access: A Comparative Study

Purpose

This study aimed to evaluate the safety and patency rate of bovine mesenterial vein grafts (BMVG) for vascular access (VA) in hemodialysis patients (HDP), compared to expanded polytetrafluorethylene (ePTFE grafts) over a mid- to long-term period.

Methods

Patency and complication rate of 23 consecutive HDP with BMVG for VA were compared to a control group consisting of 23 similar HDP with ePTFE grafts. In both groups, the graft was placed preferably in a forearm loop configuration. The same surgeon performed all procedures. All patients were followed over a period of 4 yrs.

Results

Graft placement was successful in all patients. Patency rates did not differ significantly in both groups. However, there were less severe complications in the BMVG group.

Conclusion

The BMVG is a viable alternative for HD access in patients where autologous construction is not possible, and should be given priority in patients with a failed ePTFE graft or high risk for infection.

Vascular access for Chronic Dialysis using the Superficial Femoral Vein

Purpose

We report our experience in using the superficial femoral vein to create hemodialysis (HD) arteriovenous (AV) fistulas. Surgery was performed on six patients (four female, two male). Indications for surgery included previous fistula loss, graft infection and exhaustion of typical shunt sites.

Methods

The femoral vein was evaluated preoperatively, by Doppler ultrasound, harvested by one long incision on the anteromedial surface of the thigh, followed by suction drainage. In four patients, harvested veins were transplanted in the arm between the brachial artery and axillar vein, followed by an end-to-side anastomosis. In two patients, the venous graft remained on the anterior surface of the thigh. In those patients, they were extended with either a piece of polytetrafluoroethylene (PTFE) graft or the saphenous vein.

Results

Follow-up ranged between 14 months and 2 yrs, ensuring proper dialysis. Two patients presented with complications, including lower leg swelling and axillary lymphorrhea, which subsided spontaneously.

Conclusions

We recommend this type of AV fistula, especially in difficult cases, where all other classical vascular approaches have been used. However, the procedure is time consuming and requires experience in vascular surgery.

Prosthetic Arteriovenous Grafts for Hemodialysis

Introduction

Prosthetic arteriovenous (AV) grafts are indicated in patients with failed AV fistula (AVF), exhausted superficial veins or unsuitable vessels. Increasing the proportion of prevalent hemodialysis (HD) patients using autogenous AVF should reduce the need for AV grafts and associated morbidity. This paper reviews the current role of prosthetic AV grafts in vascular access for HD.

Technical considerations

Prior to the insertion of a prosthetic AV graft, a comprehensive review of previous access procedures and full physical examination in addition to vessel mapping is required. Anastomotic technique should take into account the flow diffuser concept, graft geometry and an anastomotic angle of 15° in order to reduce the incidence of intimal hyperplasia.

Results

Many authors report 1 and 2-yr cumulative graft patency rates of 59–90% and 50–82%, respectively. The major drawbacks with synthetic grafts include: thrombosis, a five-fold increase in infection risk and steal syndrome. The choice between surgical and percutaneous methods of dealing with blocked AV grafts remains controversial, though percutaneous techniques are assuming an increasingly important role. Percutaneous strategies are successful in declotting access in 67–95% of cases. Stenting of stenotic lesions following thrombectomy improves secondary patency rates. Strategies for dealing with AV graft infection include antibiotic prophylaxis, partial, subtotal or total graft excision and the use of biological prosthesis.

Conclusions

Though more prone to complications than autogenous AVFs, AV grafts offer a short maturation period and are more amenable to thrombectomy by radiological or surgical means. Complex AV grafts may be appropriate in patients with exhausted access sites.

Clinical results of biologic prosthesis: A systematic review and meta-analysis of comparative studies

Background

Biologic prosthesis (BP) has been reported as a safe alternative to polytetrafluoroethylene (PTFE) in vascular reconstruction. However, efficacy of BP remains controversial. We, therefore, conducted a systematic review to summarize previous available evidences comparing the BP and PTFE in terms of clinical outcomes.

Materials and methods

A literature search of the MEDLINE and Scopus was performed to identify comparative studies reporting outcomes of BP, PTFE, and/or autologous veins graft (VG) in vascular access for hemodialysis or femoropopliteal bypass. The outcome of interest was graft patency. Two reviewers independently extracted data. Meta-analysis with a random-effect model was applied to pool a risk ratio (RR) across studies.

Results

Among 584 articles identified, 11 studies (4 randomized controlled trials (RCT) and 7 cohorts) comprising 2627 patients were eligible for pooling. Seven studies compared BP with PTFE and 3 studies compared PTFE with VG. Among BP vs PTFE, pooling based on 3 RCTs yielded the pooled RR of 1.54 (95% CI: 1.10, 2.16), indicating 54% higher graft patency in VG than PTFE. Adding the 7 cohorts in this pooling yield similar results with the pooled RR of 1.29 (95% CI: 1.15, 1.45). The pooled RR of graft patency for BP vs VG was 0.74 (95% CI, 0.55, 1.00), indicating 26% lower graft patency in BP than VG.

Conclusions

Our first meta-analysis indicated that the biosynthetic prosthesis might be benefit over PTFE by increasing graft patency. An updated meta-analysis or a large scale randomized control trial is required to confirm this benefit.

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This study summarized the gap of knowledge of clinical outcome when compare with biologic prosthesis and PTFE.

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This first meta-analysis was shown clearly about results and high performance of study were collected.

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For the conclusion, high efficacy of alternative treatment was shown, however, further study needed to confirm the results.

Arteriovenous Access Failure, Stenosis, and Thrombosis

Vascular access–related complications can lead to patient morbidity and reduced patient quality of life. Some of the common arteriovenous access complications include failure to mature, stenosis formation, and thrombosis.

Midterm experience of ipsilateral axillary-axillary arteriovenous loop graft as tertiary access for haemodialysis

Objectives. To present a series of ipsilateral axillary artery to axillary vein loop arm grafts as an alternative vascular access procedure for haemodialysis in patients with difficult access. Design. Retrospective case series. Methods. Patients who underwent an axillary loop arteriovenous graft from September 2009 to September 2012 were included. Preoperative venous imaging to exclude central venous stenosis and to image arm/axillary veins was performed. A cuffed PTFE graft was anastomosed to the distal axillary artery and axillary vein and looped on the arm. Results. 25 procedures were performed on 22 patients. Median age was 51 years, with 9 males and 13 females. Median number of previous access procedures was 3 (range 0–7). Median followup was 16.4 months (range 1–35). At 3 months and 1 year, the primary and secondary patency rates were 70% and 72% and 36% and 37%, respectively. There were 11 radiological interventions in 6 grafts including 5 angioplasties and 6 thrombectomies. There were 19 surgical procedures in 10 grafts, including thrombectomy, revision, repair for bleeding, and excision. Conclusions. Our series demonstrates that the axillary loop arm graft yields acceptable early patency rates in a complex group of patients but to maintain graft patency required high rates of surgical and radiological intervention, in particular graft thrombectomy.

Upper extremity axillary loop grafts: an opportunity in hemodialysis access

Background

Dialysis vascular access complications are considered as significant causes of morbidity in chronic hemodialysis patients.

Objectives

The aim of the present study was a comparison of axillary loop and straight grafts patency and its complications in hemodialysis access.

Patients and Methods

In this cohort study conducted at Shahid Beheshti Medical University, 77 patients who underwent placement of loop or straight access grafts were included. Demographics, primary and secondary patency rates and complications like thrombosis, infection, bleeding, steal syndrome and other complications were compared in these two groups. The collected data was analyzed by chi-square test, t-test, and logistic regression.

Results

Primary patency rate in straight and loop groups after 1 month were 88.9% and 92.3% respectively (P = 0.721), and after 24 months were 31% and 55.5% respectively (P = 0.058). Secondary patency rate in straight and loop groups after 3 months were 75.6% and 92.3% respectively (P = 0.189), and after 24 months were 37.9% and 66.7% respectively (P = 0.044). The frequency of complications were the same among two methods of graft replacement and mal incidence of thrombosis, infection, delayed infection, pseudoaneurysm formation and steal syndrome occurrence ultimate graft failure and venous hypertension were not significantly different (P > 0.05).

Conclusions

Polytetrafluorethylene (PTFE) vascular graft seems to be an appropriate vascular access and is a promising alternative when upper extremity arteriovenous fistulas cannot be constructed. Additionally, there was no significant difference between the two groups for complications and early patency, but late patency was improved in loop group. More study is necessary for a conclusive assessment.

[Vascular grafts as access for hemodialysis]

Prosthetic arteriovenous grafts have an inferior patency rate and greater morbidity than those with autogenous vessels and are therefore considered as secondary or tertiary vascular access for hemodialysis in patients with fatigued or unsuitable superficial arm veins. Prior access planning in accordance of patient characteristics, careful operative procedure and appropriate revision of complications can ensure long-term functioning of a vascular access using a large variety of possible prosthetic conduits. Arteriovenous grafts remain essential in vascular access surgery and their role may be increasing with higher comorbidities of patients and should be preferred to tunnelled cuffed catheters. This article reviews the indications, alternative configurations and characteristics of arteriovenous grafts.

Allogenous vein graft as vascular access for hemodialysis--lost battle?

PURPOSE

The purpose of this paper is to assess a long-term outcome of allogenous vein grafts (ALVG) as vascular access for hemodialysis.

MATERIALS AND METHODS

For nearly eight years (between 9/2002 and 9/2011) a total of 78 patients with 112 ALVGs were involved in the study. The register included 46 women and 32 men, mean age 66.1 ± 11.2 years; range 20-88 years. The patient database was retrospectively reviewed and statistical processing was performed.

RESULTS

Almost all ALVGs were treated by PTA or surgically, very often repeatedly. The number of radiologic interventions was 316, the number of surgical procedures 31. Mean follow-up time was 795 days, range 28-3522 days. Thirty-five patients died of unrelated causes, nineteen with functional graft, fourteen patients were lost to follow-up. Forty ALVGs failed for various reasons, mostly because of occlusion. Only one patient underwent successful renal transplantation, no patient converted to peritoneal dialysis. Thirty-seven ALVGs remain correctly functioning. Primary patency rates at 6, 12, and 24 months were 81 ± 5%, 63 ± 5%, and 34 ± 2% respectively. Secondary patency rates at 6, 12, and 24 months were 96 ± 2%, 82 ± 4%, and 65 ± 5% respectively.

CONCLUSIONS

Allogenous vein grafts, in spite of the high number of necessary radiologic and surgical interventions and reinterventions, show acceptable clinical usability and durability, comparable with other types of prosthetic grafts.

Patency rate and complications of polytetrafluoroethylene grafts compared with polyurethane grafts for hemodialysis access

BACKGROUND

The survival of hemodialysis patients requiring dialysis depends on the long-term functioning and patency of the vascular access. Prosthetic vascular grafts are inevitably used for patients whose vessels are unsuitable for an autogenous arteriovenous (AV) fistula. The purpose of this study was to compare the patency rate and associated complications using different types of grafts.

METHODS

This prospective study was conducted on patients who did not have an appropriate vein for arteriovenous fistula from January 2004 through July 2006. They were divided into two groups, sex, age, and basic data matched. Polytetrafluoroethylene (PTFE) and polyurethane (PVAG) were the two types of grafts used in this study. The functionality of the graft was assessed immediately 1 day and 2 weeks after operation. The clinical follow-up was performed each 3 months until 24 months.

RESULTS

One-year patency rate was reported to be 64% and 52% in the PTFE and PVAG groups, respectively. There was no significant difference in 1-year (64% versus 52%) and 2-year (49% versus 41%) patency rate of the PTFE and PVAG grafts used as vascular access. There was also no difference between the numbers of complications reported in the two groups.

CONCLUSION

It could be concluded that either PTFE or PVAG grafts can be used with the same expected outcomes.

Outcomes of two different polytetrafluoroethylene graft sizes in patients undergoing maintenance hemodialysis

Arteriovenous access creation is mandatory for maintenance hemodialysis. If native fistula placement was not possible or failed, a prosthetic conduit would be the best substitute. The purpose of this prospective study was to compare outcomes of two different sizes of polytetrafluoroethylene (PTFE) grafts, in hemodialysis patients, at the Mustafa Khomeini Hospital in Iran. The study population consisted of 586 end-stage renal disease referrals for vascular access construction (January 2003 to January 2007) of which eventually 102 subjects were candidates for PTFE graft who were followed for one year. Data were collected by a questionnaire and analyzed using the SPSS, life table, Kaplan- Meier and Log-Rank tests. Out of 102 PTFE implantation candidates (mean value of age 51.7 +/- 17.06 yrs), 56% were male and 44% female. PTFE grafts of 8 mm and 6 mm sizes were randomly placed in 57 and 45 subjects, with distribution of 83%, 12% and 5% in arm, forearm and thigh. The most underlying diseases were hypertension and diabetes. There was a significant difference in complication rates between patients with and without underlying diseases [42% vs. 10% (P = 0.03)]. One-year patency rates were 42.2% and 36.5% for 6 mm and 8 mm grafts and 28.2% vs. 52% in patients with and without underlying diseases respectively. Despite more complication frequency in 8 mm grafts, the patency and complication rates of two graft groups did not significantly differ. Hypertension and diabetes could have contributory roles in graft complication rate, which may be preventable. Non-tapered grafts of 6 mm and 8 mm sizes have not significant different outcomes. Further research is recommended with larger sample size and longer duration.

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.

Randomized clinical trial comparing decellularized bovine ureter with expanded polytetrafluoroethylene for vascular access

BACKGROUND

The SynerGraft model 100 (SG 100) is a decellularized bovine uereter graft developed to improve on prosthetic conduits for vascular access. Its clinical performance was compared with polytetrafluoroethylene (ePTFE) in a prospective, pilot randomized study.

METHODS

Patients requiring haemodialysis with no native vein options were included. Between June 2004 and June 2007, 29 patients received SG 100 and 27 ePTFE grafts. Forty-five patients had undergone previous access surgery. All grafts were between the brachial artery and the axillary vein.

RESULTS

Clinical details were similar between the groups; overall mean(s.d.) follow-up was 469(398) days. After 1 year, there were no significant differences in primary patency (28 per cent for SG 100 versus 48 per cent for ePTFE; P = 0.290), assisted primary patency (52 versus 64 per cent; P = 0.430) or secondary patency (57 versus 68 per cent; P = 0.370). Freedom from infection at 1 year was 96 per cent for SG 100 and 91 per cent for ePTFE (P = 0.410). Fifty-seven further procedures (18 endovascular and 39 surgical) were needed to maintain patency in 50 grafts (23 SG 100 and 27 ePTFE).

CONCLUSION

Both grafts were adequate conduits for haemodialysis and were amenable to repair. Anticipated advantages for SG 100 were not seen in either patency or stability.

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.

ProCol vascular bioprosthesis for vascular access: midterm results

BACKGROUND/AIMS

This study aimed to evaluate the safety and efficacy of the ProCol vascular bioprostheses as vascular access (VA) material, especially in patients with a history of prior failed access.

METHODS

During a 20-month period, 25 arteriovenous (AV) bovine vein grafts were placed in 24 hemodialysis (HD) patients for VA. All patients presented with failed autologous access sites.

RESULTS

Graft placement was successful in all patients with no procedure-related complications. Follow-up from 6-26 months gave primary 6-month, 12-month and 24-month patency rates of, respectively, 90%, 80% and 70%. Graft characteristics in cannulation and hemostasis were very satisfying.

CONCLUSION

Our midterm results demonstrated that the ProCol vascular bioprosthesis was a promising material for VA with good patency and low complication rates.

Multicenter Evaluation of the Bovine Mesenteric Vein Bioprostheses for Hemodialysis Access in Patients with an Earlier Failed Prosthetic Graft

BACKGROUND

The number of patients requiring hemodialysis increases each year, with a large cohort of patients still requiring prosthetic grafts for hemodialysis. All available prosthetic vascular access grafts have predictable failure rates, leading to a large group of patients with multiple failed access grafts. This report evaluates use of mesenteric vein bioprosthesis (MVB) as a conduit for patients who have failed at least one earlier synthetic vascular access graft.

STUDY DESIGN

Two-hundred seventy-six access grafts were implanted in patients who had at least one earlier failed synthetic graft. Of these grafts, 183 were MVB and 93 were synthetic. Graft histories were obtained from 128 of the 183 patients who received the MVB, representing a nonrandomized historic data set of previously failed grafts as an internal control group (INT). Patency was determined by Kaplan-Meier analysis, and the Cox proportional hazards model was used for multivariate analysis of factors predictive of effect.

RESULTS

Primary patency at 12 months was 35.6% MVB versus 28.4% synthetic grafts. At 24 months, secondary patency was 60.3% MVB, 42.9% synthetic, and 18.0% INT (p < 0.0001, log- rank). Complication rates, including dilation, seroma, infection, and thrombosis, were all notably lower for the MVB compared with synthetic grafts by Cox regression (p < 0.001). Intervention rate per patient year was lower in the MVB group (0.97 versus 1.37) compared with synthetic grafts (p = 0.003).

CONCLUSIONS

MVB provided superior secondary graft patency compared with both historic graft data or newly implanted nonrandomized synthetic implants. A considerable reduction in thrombosis, infection, and interventions was observed with the MVB graft. These results suggest that MVB offers a safe alternative to patients who have a history of failing synthetic access grafts and may represent an option for extending vascular access to this patient population.

Intermediate Outcome and Risk Factor Assessment of Bovine Vascular Heterografts used as AV-Fistulas for Hemodialysis Access

OBJECTIVES

This observational study was set up to prospectively follow all bovine heterograft (ProCol) fistulas implanted for hemodialysis access between 1998 and 2002.

METHODS

ProCol was implanted if autogenous vein was not available or if patients presented with a history of failed, infected or otherwise complicated ePTFE grafts and/or on immunosuppressive therapy. Fistula patency was the primary outcome; secondary outcomes were clinical events and the rate of access revisions.

RESULTS

Sixty-two ProCol grafts were implanted in 56 patients. The mean primary (PP) and secondary patency (SP) was 334 (SEM 57) and 528 (SEM 59) days, respectively. Coronary heart disease was associated with a significantly better SP (OR 0.2, 95% CI 0.1-0.9) whilst diabetes mellitus was associated with a significantly worse SP (OR 0.2, 95% CI 0.1-0.9). Reinterventions were performed at a mean rate of 1.23 (SEM 0.17) per fistula. The relative risk of access revision was significantly higher in patients with diabetes mellitus (OR 9.2, 95% CI 2.3-37.2).

CONCLUSIONS

ProCol grafts, used for AV-fistulas, demonstrate acceptable patency rates in high-risk haemodialysis patients. Diabetes mellitus jeopardizes the patency of these fistulas and is associated with a high revision rate.

Hypercoagulable states and antithrombotic strategies in recurrent vascular access site thrombosis

Vascular access site thrombosis is a major cause of morbidity in patients receiving hemodialysis. The role of hypercoagulable states in recurrent vascular access site thrombosis remains poorly understood. Data are limited regarding systemic anticoagulation to improve access graft patency, because of concern about hemorrhagic complications. We determined the prevalence of hypercoagulable states and clinical outcome (thrombotic and hemorrhagic) after initiation of antithrombotic therapy in a series of patients with recurrent vascular access site thrombosis. We evaluated 31 patients who had sustained 119 thrombotic events that resulted in vascular access graft failure during the year before evaluation. Sixty-eight percent of patients tested had elevated concentrations of antibody to anticardiolipin or topical bovine thrombin, and 18% of patients tested had heparin-induced antibodies. More than 90% of patients had elevated factor VIII concentration, 62% had elevated fibrinogen concentrations, and 42% had elevated C-reactive protein concentrations. Twenty-nine patients were given antithrombotic therapy: 13 with warfarin sodium, 12 with unfractionated heparin (UFH), and 11 with low molecular weight heparin (LMWH). Seven patients received more than one antithrombotic agent, sequentially. Nineteen patients have had no thrombotic events since beginning antithrombotic therapy (10 with warfarin, 3 with UFH, 6 with LMWH). Mean follow-up was 8.6 months (median, 7 months). Eight patients sustained 10 bleeding complications (5 with warfarin, 3 with UFH, and 2 with LMWH). In conclusion, hypercoagulable states are common in patients with recurrent vascular access site thrombosis. Antithrombotic therapy may increase vascular access graft patency, but is associated with significant risk for hemorrhage. Prospective studies are needed to evaluate the role and safety of antithrombotic agents in improving vascular access graft patency.

Vascular access surgery managed by renal physicians: the choice of native arteriovenous fistulas for hemodialysis

BACKGROUND

After decades of success in dialysis research and treatment, prompt availability of a well-functioning vascular access for dialysis remains a disturbing problem. On the basis of a single-center experience in which nephrologists are responsible for access surgery, we sought to identify predictors of catheter use at the start of hemodialysis (HD) therapy and risk factors affecting first permanent access survival.

METHODS

Demographics, comorbid conditions, predialysis follow-up, and access-related procedures of the 197 consecutive patients beginning extracorporeal treatment between 1995 and 2001 were prospectively entered into our database.

RESULTS

Despite the high prevalence of comorbidities (diabetes, 22%; cardiovascular disease, 50%; neoplasm, 15%), all subjects received a native fistula as a first permanent access, but almost 60% initiated HD therapy using a catheter. The latter showed more comorbidities and were referred later. According to the Kaplan-Meier method, median primary and secondary survivals of the first fistula were 38.1 months and more than 70 months, respectively. The Cox model indicated that diabetes and previous catheter use were independently associated with 85% and 63% greater relative risks for first failure, but only diabetes led to a greater risk for final failure (relative risk, 2.38; P = 0.05).

CONCLUSION

Both the absence of predialysis care and presence of comorbidity influence access type at HD therapy initiation and fistula survival. Earlier intervention strategies can increase the use and durability of a native fistula for HD. Direct involvement of nephrologists in the management of access surgery can be helpful in this respect.

Permanent hemodialysis vascular access survival in children and adolescents with end-stage renal disease

BACKGROUND

Transplantation is the optimal therapy for pediatric end-stage renal disease (ESRD) patients, but in a subset of patients with peritoneal membrane failure, failed transplants or poor social situations, chronic hemodialysis (HD) remains the only option. Long-term survival of arteriovenous fistulas (AVFs) and arteriovenous grafts (AVGs) in pediatric patients has not been well described.

METHODS

We studied the survival of permanent vascular access in 34 pediatric ESRD patients treated with chronic HD at our institution between 1/1/89 and 12/1/95 and followed to 12/31/2000.

RESULTS

Twenty-four AVFs and 28 AVGs were created in 19 and 23 patients, respectively. Mean age and weight at insertion were 15.1 years (range 7.1 to 20.9) and 46 kg (18 to 81) for AVFs and 13.3 years (3.8 to 21.1) and 41.5 kg (10.5 to 145) for AVGs. Fifteen patients weighed <35 kg at the time of access creation (7 AVFs in 5 patients, 14 AVGs in 13 patients). Excluding primary failures, one-year, three-year and five-year patency rates for AVFs (74%, 59%, 59%) and AVGs (96%, 69%, 40%) were not significantly different. Patency did not correlate with patient weight or age at access creation. Primary access failure occurred more often (P < 0.01) in AVFs (8/24) compared to AVGs (1/28). Access thrombosis, stenosis and infection occurred more frequently in AVG (P = 0.02).

CONCLUSIONS

Both AVF and AVG function well even in small pediatric patients and have survival rates equivalent to adult series and longer than cuffed venous catheters in pediatric patients. Both AVFs and AVGs are preferable for long-term HD access in pediatrics.