Vascular access for haemodialysis

Guidelines on vascular access for hemodialysis from the Brazilian Society of Angiology and Vascular Surgery

Chronic kidney disease is a worldwide public health problem, and end-stage renal disease requires dialysis. Most patients requiring renal replacement therapy have to undergo hemodialysis. Therefore, vascular access is extremely important for the dialysis population, directly affecting the quality of life and the morbidity and mortality of this patient population. Since making, managing and salvaging of vascular accesses falls within the purview of the vascular surgeon, developing guideline to help specialists better manage vascular accesses for hemodialysis if of great importance. Thus, the objective of this guideline is to present a set of recommendations to guide decisions involved in the referral, evaluation, choice, surveillance and management of complications of vascular accesses for hemodialysis.

Oversized balloon angioplasty for endovascular maturation of arteriovenous fistulae to accelerate cannulation and to decrease the duration of catheter use

BACKGROUND

The functional autologous arteriovenous fistula is considered the best vascular access for patients on hemodialysis. Some fistulae exhibit maturation problems after creation and do not reach adequate vessel diameter and flow in dialysis. The aim of this study was to describe our technique of oversized balloon angioplasty for assisted maturation of arteriovenous fistulae to accelerate the cannulation and to decrease the time of catheter use and its outcome.

METHODS

A retrospective analysis of balloon-assisted procedures for maturation failure was performed in a single center between October 2011 and January 2019. Patients underwent imaging procedures to identify stenosis, followed by angioplasty using oversized high-pressure balloons from the anastomosis to the deep venous outflow tract. The flow volume, time interval of use of the fistula and removal of the catheter, patency rates, and complications rates were evaluated.

RESULTS

Seventy-eight patients underwent 124 balloon angioplasty procedures. Technical and clinical success was achieved in 91% of the cases. In patients in whom maturation was successful, the fistula was cannulated in a mean time of 5 days after the procedure (range, 1-20 days). On average, catheter removal was performed 14 days (range, 5-33 days) after the maturation procedure. The mean flow volume in the fistula before the procedure was 276 ml/min (range, 122-488 ml/min) and 24 h after the maturation was 1014 ml/min (range, 760-1800 ml/min).The primary patency rate at 3, 6, and 12 months was 87.3%, 66.2%, and 50.7%, respectively. Assisted primary patency was 100% at 3 months, 92.9% at 6 months, and 90.0% at 12 months. Minor complications occurred in 18% of cases, and major complications in 4.8%.

CONCLUSIONS

The oversized balloon-assisted arteriovenous fistula maturation technique is safe and effective, allowing the cannulation of the fistulae a few hours or days after the procedure and decreasing the time of catheter use.

Outcome of Cuffed Tunneled Dialysis Catheters for Hemodialysis Patients at a Tertiary Care Hospital: A Descriptive Cross-sectional Study

Introduction:

Arteriovenous fistula is the most common vascular access for patients requiring hemodialysis, but it is not always possible or practical hence cuffed tunneled dialysis catheter comes into play. The aim of the study was to determine the outcome of cuffed tunneled dialysis catheter used for hemodialysis at a teaching hospital.

Methods:

A descriptive cross-sectional study was conducted between January 2014 and December 2019 on 103 chronic dialysis patients with end-stage renal disease presenting to a tertiary care hospital. Ethical approval was received from the institutional review board (2/(6-11) E2/076/77). Whole sampling was done. Data entry and analysis were done in Microsoft Excel 10.

Results:

The study included 103 patients with 117 cuffed tunneled dialysis catheters placed for hemodialysis. On assessing the outcome of the catheters, the primary and secondary patency rates of the catheters were 5.85±4.87 and 1.21±3.77 months. Thirty-one (30.1%) patients required one intervention, and 11 (10.68%) catheters required 3 or more interventions to maintain patency. Eighteen (17.48%) patients presented with catheter dysfunction while in 11 (10.68%) cases, the catheter was kinked or malpositioned at the notch. In one patient, procedure was abandoned due to severe bleeding and in 2 (1.94%) patients dialysis catheters could not be negotiated into the right atrium and left in brachiocephalic junction.

Conclusions:

Cuffed tunneled dialysis catheter is effective for maintenance hemodialysis in patients with the end-stage renal disease if used with proper care during dialysis even in our setup. The results and outcomes of the procedure are at par with standards.

Long-term results of thigh arteriovenous dialysis grafts

INTRODUCTION:

A proportion of hemodialysis patients exhaust all options for arteriovenous access in upper extremities. Arteriovenous thigh grafts are a potential vascular access option in such patients.

METHODS:

We performed a retrospective study of all thigh arteriovenous access grafts placed between 1995 and 2015. The clinical, demographic patient information and patency of each thigh graft was determined from the time of surgical creation placement until abandonment, transfer to other modality, or center or end of study, and the reason for access failure documented.

RESULTS:

In total, 44 patients received 49 thigh arteriovenous accesses. The average age was 60 years (13-79 years); Half (53%) of the patients (n = 24) were female and 61% of the patients (n = 30) of arteriovenous accesses were left-sided. The cumulative proportion surviving (primary patency rates) at 12, 24, and 28 months were 43% (standard error = 9%), 33% (standard error = 9%), and 13% (standard error = 9%), respectively. The cumulative proportion of surviving grafts at 12, 24, and 48 months were 61% (standard error = 8%), 58% (standard error = 9%), and 31% (standard error = 13%), respectively. In total, 37 revisions were performed in 22 patients to maintain patency or eradicate infection. Infection occurred in 20 patients (39%) of thigh grafts requiring 16 patients (80% of those affected) to be removed; 14 patients had grafts (33.3%) that served as the lone hemodialysis arteriovenous access during the patients' lifetime on dialysis.

CONCLUSION:

Arteriovenous thigh graft access is used infrequently, but they have an acceptable patency. Some accesses require revisions and they have a high infection rate. Despite this, an acceptable proportion of leg grafts provide durable access for the dialysis lifetime of the patient.

A Hybrid Approach to Salvage a Failing Long-Standing Autogenous Aneurysmal Fistula in a Hemodialysis Patient

Very few studies have addressed the repair of autogenous and prosthetic-related false arteriovenous access (AVA) aneurysms in hemodialysis patients. Surgical management of complicated AVA-related aneurysms remains the gold standard method although covered stents have recently been introduced for the exclusion of such aneurysms, offering a minimally invasive therapy. In this paper, we describe a combination of open and endovascular repair for treating an anastomotic and a puncture-site aneurysm to salvage a failing long-standing autogenous radial-cephalic fistula in the wrist. Resection of the anastomotic aneurysm and reconstruction of the anastomosis proximally was initially performed. Via the first cm of the anastomosis, a Fluency® stent graft (SG) was inserted and it successfully excluded the mid-outflow vein false aneurysm. Such hybrid therapies may be the future of AVA revisions and this trend should not be overlooked by nephrologists and vascular surgeons.

Multi-Slice Computed Tomographic Angiography for Stenosis Detection in Forearm Hemodialysis Arteriovenous Fistulas

Purpose

A method of diagnosing the extent and severity of arteriovenous fistula (AVF) stenoses is multi-slice computed tomographic angiography (MS-CTA). The aim of this prospective study was to assess the accuracy of MS-CTA for the detection and grading of stenoses in AVF in comparison to digital subtraction angiography (DSA), which was used as the gold standard of reference.

Methods

Fifteen hemodialysis (HD) patients with dysfunctioning forearm AVF were included. These AVFs were evaluated by both DSA and MS-CTA and were read in a prospective, blinded manner by two radiologists experienced in vascular imaging.

Results

ROC analysis revealed areas under the curve of 0.90 ± 0.07 for observer I and 0.87 ± 0.08 for observer II at a stenosis cut-off level of ≥50% diameter reduction. The combined results for MS-CTA showed sensitivity, specificity and positive and negative predictive values of 82%, 98%, 82% and 98% for stenoses ≥50% and 71%, 99%, 77% and 98% for stenoses ≥75%. Inter-observer agreement for the detection of stenoses ≥50% diameter reduction was 0.70 and 1.0, for MS-CTA and DSA, respectively.

Conclusion

MS-CTA can provide good visualization of forearm HD access AVF and has moderate sensitivity, but high specificity for the detection of flow-limiting stenoses.

Bridging to a High Flow Upper Arm Native Fistula for Hemodialysis with the LifeSite® Hemodialysis Access System

Permanent vascular access for chronic hemodialysis requires a reliable structure with adequate blood flow. Endogenous arteriovenous (AV) fistulas offer the best outcomes, but standard radiocephalic fistulas are not always feasible. A reliable alternative is a transposed basilic vein-brachial artery AV fistula, which offers a number of advantages over synthetic AV grafts. The transposed basilic vein fistula provides high flow rates along with low rates of infection, thrombosis, and other complications; however, longer maturation times may be necessary. This longer maturation time may necessitate the use of a “bridge device” for access. The new, fully subcutaneous vascular access device - the LifeSite® Hemodialysis Access System - offers several significant advantages over a standard dialysis catheter as a bridge device: higher flow rates without recirculation, as well as lower rates of infection, thrombosis, and hospitalization. This article describes the surgical procedure for the creation of the transposed basilic vein fistula and the implantation procedure for the LifeSite System. We report on the use of this combined sequential approach to vascular access in 14 patients with excellent results. All 14 patients initially implanted with the LifeSite System were successfully bridged to a functional transposed basilic vein fistula. The mean flow rate with the LifeSite System was 450 ml/min; only one device had to be removed due to infection in an HIV-positive patient, and no other complications were observed. The mean time to maturation of the transposed basilic vein fistula was 6 months; the upper arm fistulas delivered a mean flow rate of 1100 ml/min with a 100% patency rate at 6 months. The sequential use of the LifeSite System and a transposed basilic vein fistula represents a valuable approach to increasing the usage of a high flow native AV fistula.

Steal Syndrome after Brachiocephalic Fistula for Vascular Access: Correction with a New Simple Surgical Technique

Purpose

Steal syndrome is the condition of arterial insufficiency distal to a permanent haemodialysis fistula. Three treatment options have been recommended: ligation of the fistula, banding of the fistula, and distal revascularization. We report an alternative simple surgical technique for correction of steal syndrome.

Methods

Two patients were treated for steal syndrome after brachiocephalic fistula operation. The treatment of the steal syndrome was done by interponating an ePTFE graft loop tunnelated subcutaneously in the upper arm.

Results

At follow-up one year later both fistula were patent without any reoperation and with normal flow at haemodialysis. There were no symptoms of steal.

Conclusion

This new method for correction of steal syndrome seems to be an attractive alternative.

Steal Syndrome of the Hemodialysis Vascular Access: Diagnosis and Treatment

Purpose

Steal syndrome is an uncommon but serious condition of arterial insufficiency distal to a permanent hemodialysis fistula. The management of the condition is a great challenge to the surgeon because of the conflicting goals of preserving the fistula and treat the ischemia. In this review the purpose was to analyze the clinical problem and treatment possibilities.

Methods

Medline and Embase databases were searched for studies relevant to diagnosis and management of steal syndrome of the hemodialysis vascular access.

Results

The diagnosis of steal syndrome is largely based on clinical features and non-invasive studies. In same cases angiography may be necessary to find out the real causes of the steal syndrome. The cause is usually high fistula flow but other causes as steal phenomenon, inflow, outflow or anastomotic stenosis have to be considered and even combination of causes. The main treatment options are some form of flow reducing procedure or the distal revascularization interval ligation method. In some cases simple distal arterial ligation is the method of choice. Furthermore, in some patients a stenosis has to be treated as the first treatment option.

Conclusion

For an appropriate treatment of a steal syndrome a careful analysis of the cause is important.

Surgery versus Interventional Radiology in the Management of Thrombosed Vascular Access for Hemodialysis

Thrombosis is the most frequent complication occurring in vascular access (VA). The two widely used treatment strategies for thrombosed VA are surgical and endovascular. Which is the best and whether different approaches should be used on proximal versus distal VA, is still debated. This is a retrospective study. Over a three years period, we studied among a population of 475 dialysis patients, 54 VA thromboses in 46 patients. Surgical procedure was successful in 14/17 (82%) distal artero-venous fistulas (AVF) while, in 9 proximal AVF, it led to initial success in 6 patients (66%), with a six months primary patency respectively of 93% and 84%. Radiological procedure resolved 6/10 distal AVF (initial success 60%) with primary patency of 66%, and was successful in 16/18 proximal AVF (initial success 89%) with primary patency of 81%. Taking our data all together, no differences are found between two thrombolitic (surgical and endovascular) procedures. But results were different in thrombosed proximal VA (where endovascular treatment should be preferred) versus distal ones (where surgery seems better).

Comparison of standard forearm prosthetic loop grafts to composite semiloop forearm grafts ("semi-grafts") in hemodialysis patients: A prospective study

INTRODUCTION

To prospectively assess the performance of composite semiloop antebrachial grafts ("semi-grafts," SGs) in hemodialysis patients.

METHODS

Eighty-five patients who received 67 loop antebrachial grafts (LG-group) and 25 antebrachial semigrafts (SG-group) were enrolled. SGs were defined as those originating from the brachial artery and anastomosed with the proximal mature mid-antebrachial cephalic vein. Cephalic vein length should be at least 10 cm in length and of ≥5 mm in diameter for inclusion in the SG-group. LG-group included all possible outflow vein options of minimum diameter 3 mm. Kaplan-Meier statistics was used for comparison of groups.

FINDINGS

Main indication for a SG was a failing radiocephalic fistula with extensive distal cephalic vein stenosis not amenable to correction or failed after endovascular repair or requiring long interposition grafting. The mean follow-up period was 20.16 ± 22.6 and 29.6 ± 36.7 months for the LG- and SG-group, respectively (P = 0.14). Forty-two patients died during the follow-up. Primary patency (up to first intervention or failure) at 6 and 12 months for LG- vs. SG-group was 93.9% vs. 83.7% and 47% vs. 55.8% (P = 0.08). Secondary patency (up to abandonment) was 58.2% vs. 61.1% and 36% vs. 45.8% at 12 and 24 months (P = 0.18). Mortality at 48 months was 22.4% (LG-group) and 24% (SG-group) (P = 0.9).

DISCUSSION

There was a trend toward better primary and secondary patency rates for the SGs especially in the long-term. This is a valuable option in selected patients that access surgeons and nephrologists should be aware of.

Surgical interventions for late complications of arteriovenous fistulas

Our aim was to determine the most effective surgical treatment for arteriovenous fistula (AVF) complications after all other methods of salvage have failed. We evaluated 110 patients for 139 complications that occurred after the initial AVF placement and for whom surgical intervention was the last hope for retaining fistula access. Vascular steal syndrome and venous hypertension were the most common complications seen in our patients. The anastomoses of 17 of the vascular steal syndrome cases were narrowed either by stitches or by a polytetrafluoroethylene graft. The second most performed revision surgery was excision of the aneurysm and repair with primary suturing, followed by excision of the aneurysm and interposition grafting. Successful surgical outcomes were achieved in 111 of 139 procedures after revision surgery without constructing a new AVF. AVF salvage surgery is of paramount importance in order to increase the patency rate, which prolongs survival and increases the patient's quality of life.

No-Touch Technique for Radiocephalic Arteriovenous Fistula – Surgical Technique and Preliminary Results

Purpose

The radiocephalic arteriovenous fistula (RC-AVF) has significant failure rates due to occlusions and failure to mature. The size and quality of the veins are considerable limiting factors for the procedure. The aim of this pilot study was to describe the No-Touch technique (NTT) to create RC-AVF and present the results up to 1 year of follow-up.

Methods

Thirty-one consecutive patients who were referred for surgery for a RC-AVF were included (17 men, mean age 63 years, range 35-84) and operated by NTT where the vein and artery were dissected with a tissue cushion around it. Twenty-two patients had small veins or arteries (≤2 mm), 12 patients had a small cephalic vein (≤2 mm), and the mean distal cephalic vein diameter was 2.4 mm (range 1.0-4.1 mm).

Results

Technical surgical success and immediate patency were obtained in all patients. Clinical success was achieved in 23 of the 27 (85%) patients who required hemodialysis. The proportion of primary patency at 30 days and 6 months was 84% and 64%, respectively. Secondary patency at 30 days and 6 months was 97% and 83%, respectively. At 1-year follow-up, primary patency was 54% and secondary patency was 80%. There was no major difference in patency due to preoperative vein diameter.

Conclusions

The results of this study indicate that NTT can be used for primary radio-cephalic fistula surgery with very good results. This method offers the potential to create a RC-AVF in patients who are not usually considered appropriate for a distal arm fistula due to a small cephalic vein.

Percutaneous transluminal angioplasty for dysfunctional femoral hemodialysis graft

PURPOSE

We aimed to evaluate the safety and effectiveness of percutaneous transluminal angioplasty (PTA) for dysfunctional femoral arteriovenous graft and analyze clinical or anatomic predictors of graft patency.

METHODS

The records of 45 patients who underwent PTA or thromboaspiration for dysfunctional or thrombosed femoral arteriovenous graft from 2005 to 2012 were reviewed retrospectively. Primary and secondary patency rates were determined at three, six, and 12 months after PTA. The primary patency rate was analyzed according to the presence of diabetes mellitus, graft age from the time of creation to the first intervention (<12 months or ≥12 months), presence of thrombus, shape of graft (U-shape vs. straight-shape), anastomosis type of graft (femoral-femoral vs. femoral-saphenous), location of stenosis (central vs. peripheral), length of stenosis (<2 cm vs. ≥2 cm), degree of stenosis severity (<70% vs. ≥70%), and stent insertion.

RESULTS

A total of 124 PTAs were performed in 45 patients. The primary patency rate at three, six, and 12 months was 84.8%, 63.6%, and 24.2%, respectively. The secondary patency rate at three, six, and 12 months was 95.2%, 95.2%, and 85.7%, respectively. The mean duration of primary and secondary patency was 13.2 and 35.7 months, respectively. No significant clinical or anatomical predictors of primary patency could be identified. Stent placement had a negative effect on primary patency.

CONCLUSION

PTA is a safe and effective treatment for dysfunctional femoral arteriovenous grafts. Stent placement seems to improve technical success, but does not enhance the primary patency rate of dysfunctional femoral arteriovenous grafts.

Vascular access for hemodialysis: current perspectives

A well-functioning vascular access (VA) is a mainstay to perform an efficient hemodialysis (HD) procedure. There are three main types of access: native arteriovenous fistula (AVF), arteriovenous graft, and central venous catheter (CVC). AVF, described by Brescia and Cimino, remains the first choice for chronic HD. It is the best access for longevity and has the lowest association with morbidity and mortality, and for this reason AVF use is strongly recommended by guidelines from different countries. Once autogenous options have been exhausted, prosthetic fistulae become the second option of maintenance HD access alternatives. CVCs have become an important adjunct in maintaining patients on HD. The preferable locations for insertion are the internal jugular and femoral veins. The subclavian vein is considered the third choice because of the high risk of thrombosis. Complications associated with CVC insertion range from 5% to 19%. Since an increasing number of patients have implanted pacemakers and defibrillators, usually inserted via the subclavian vein and superior vena cava into the right heart, a careful assessment of risk and benefits should be taken. Infection is responsible for the removal of about 30%-60% of HD CVCs, and hospitalization rates are higher among patients with CVCs than among AVF ones. Proper VA maintenance requires integration of different professionals to create a VA team. This team should include a nephrologist, radiologist, vascular surgeon, infectious disease consultant, and members of the dialysis staff. They should provide their experience in order to give the best options to uremic patients and the best care for their VA.

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.

Subsartorial Mid-thigh Graft for Hemodialysis Access in Patients with Exhausted Arm Veins A Novel Strategy

To study the value of a mid-thigh graft as an alternative in the provision of long-term vascular access in patients requiring hemodialysis 11 patients (9 females, 2 males) aged 27-71 (mean 48 years) with unsuitable arm veins underwent surgery between February 2001 and January 2004 to create an arteriovenous fistula (AVF) between the superficial femoral artery (SFA) and superficial femoral vein (SFV). There were no deaths due to the procedure, no limb losses, no technical failures and all fistulae matured satisfactorily. Complications included two cases of thrombosis (surgically thrombectomised at 15 and 24 months post-operatively), one case of graft infection at three years post-operatively (treated by graft excision), and one graft failure at five years post-operatively (replaced with a second graft at the same site). After three years 10 grafts were functional and being used for dialysis. It was concluded that a mid-thigh graft is a suitable durable procedure in patients where creation of vascular access at the upper limbs is not feasible. Adequate clinical and radiological surveillance is imperative.

The Brachiobasilic Arteriovenous Fistula: Effect of Patient Variables

Purpose

The hemodialysis population is constantly expanding as patients on dialysis have increased longevity and the number of kidneys available for transplantation remains static (1). After radiocephalic and brachiocephalic fistulas have been exhausted the use of the autologous brachiobasilic fistula (BBAVF) should be considered prior to use of a synthetic graft. We present our single center experience of 140 brachiobasilic fistulas in a five-year period and examine any factors that influence patency and long-term function.

Methods

Patients who had undergone formation of a BBAVF between January 2004 and January 2009 were identified; a review of all case notes and databases was undertaken. Details on demographics, cause of renal failure, co-morbidities (including diabetes, cardiac morbidity, hypertension, peripheral vascular disease), dialysis status at the time of fistula creation, hemoglobin, anti-coagulation regimens, and complications from surgery were recorded.

Results

Patency (defined as use of AVF for dialysis) was 83% at 3 months, 77% at 6 months, and 69% at 12 months. Length of patency ranged from 0 to 1918 days (at study cut-off) with a mean patency of 532 days. Factors found to significantly affect fistula patency included age over 60 ( P=<0.001) and presence of peripheral vascular disease ( P=0.048).

Conclusions

Our brachiobasilic fistula patency rates are comparable with published literature and other fistulas. Within our population patient variables including age over 60 and the presence of peripheral vascular disease are associated with worse outcomes as would be expected. In spite of these factors we feel the brachiobasilic fistula is an excellent option for patients with more challenging access and should certainly be undertaken prior to the use of prosthetic grafts.

Good long term patency rates associated with an alternative technique in vascular access surgery--the adductor loop arteriovenous graft

INTRODUCTION

We have modified the arteriovenous groin loop procedure and present a technique associated with good patency rates and low infection rates.

METHODS

We describe an alternative femoro-femoral arteriovenous loop technique which utilises the mid-thigh sub-sartorial Superficial Femoral Artery and Femoral Vein. We then performed a retrospective analysis of all such cases performed in our unit to date and analysed the patency and infection rates associated with the technique.

RESULTS

16 cases have been performed to date with a median follow-up of 18 months. The primary and secondary patency rates at one year were 70% and 90% respectively. The overall infection rate was only 12.5%.

CONCLUSIONS

Our technique is associated with good patency rates and low infection rates. In addition it preserves modesty whilst on dialysis and the groin vessels for further vascular access surgery if needed.

Evolution of shear stress, protein expression, and vessel area in an animal model of arterial dilatation in hemodialysis grafts

PURPOSE

To evaluate the wall shear stress, protein expression of matrix metalloproteinase (MMP)-2 and MMP-9 and tissue inhibitor of matrix metalloproteinase (TIMP)-1 and TIMP-2, and vessel area over time in a porcine model for polytetrafluoroethylene (PTFE) hemodialysis grafts.

MATERIALS AND METHODS

In 21 pigs, subtotal renal infarction was created, and 28 days later, a PTFE graft was placed to connect the carotid artery to the ipsilateral jugular vein. Phase-contrast magnetic resonance imaging was used to measure blood flow and vessel area at 1, 3, 7, and 14 days after graft placement. Wall shear stress was estimated from the law of Poiseuille. Animals were killed at day 3 (n = 7), day 7 (n = 7), and day 14 (n = 7) and expression of MMP-2, MMP-9, TIMP-1, and TIMP-2 were determined at the grafted and control arteries.

RESULTS

The mean wall shear stress of the grafted artery was higher than in the control artery at all time points (P < .05). It peaked by day 3 and decreased by days 7-14 as the vessel area nearly doubled. By days 7-14, there was a significant increase in active MMP-2 followed by a significant increase in pro-MMP-9 and active MMP-9 by day 14 (P < .05, grafted artery vs control). TIMP-1 expression peaked by day 7 and then decreased, whereas TIMP-2 expression was decreased at days 7-14.

CONCLUSIONS

The wall shear stress of the grafted artery peaks by day 3, with increased MMP-2 activity by days 7-14, followed by increase pro-MMP-9 and active MMP-9 by day 14. In addition, the vessel area nearly doubled.

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.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

[Management of perianastomotic stenoses complicating vascular accesses for haemodialysis]

OBJECTIVE

Perianastomotic stenoses (PAS) complicating native arteriovenous fistulas (AVF) of the forearm can be treated by angioplasty or surgery. The objective of this study was to report primary patency (PP) and primary assisted patency (PAP) rates of surgery and angioplasty of these stenoses. The secondary objective was to identify factors influencing the patency rates of these reoperations.

MATERIAL AND METHODS

Seventy-three patients with a mean age, 65 years were treated for PAS between January 1999 and December 2005 in two centres (Tours and Le Mans), which were retrospectively included. PAS were treated by surgery (n=21) or angioplasty (n=52). The two groups were comparable. The mean follow-up was 39 months for the angioplasty group and 49 months for the surgery group (p=0.088).

RESULTS

The PP rate was 71+/-10% for surgery and 41+/-6% for angioplasty (p<0.0175). The PAP rate was not significantly different (p=0.462) between angioplasty (92+/-4%) and surgery (95+/-4%). In the endovascular group, the site of stenosis on the anastomosis was a risk factor for early recurrence (95% CI between 0.006 and 0.392; p=0.047).

CONCLUSION

These results suggest that anastomotic stenoses should be treated surgically rather than by angioplasty. Angioplasty and surgery give identical patency rates in other types of perianastomotic stenoses at the cost of a higher reoperation rate for angioplasty.

Brachio-cephalic ('Gracz') fistula use for continuous hemofiltration in a hemodynamically unstable hemodialysis patient without venous vascular access: a case report

Even in patients with chronic renal failure and chronic intermittent hemodialysis, continuous venovenous hemofiltration (CVVH) is the most often practiced renal replacement technique in the intensive care unit. Although patients show less hemodynamic instability during CVVH than during hemodialysis, it requires a blood flow exceeding 200 ml/min in the extracorporeal circuit necessitating the use of large bore catheters. Vascular access in critically ill septic and edematous patients is sometimes difficult, or even impossible.

We describe a technique of using a brachio-cephalic arterio-venous fistula in a hemodialysis patient for continuous hemofiltration (HF) resulting in improved hemodynamic stability.

Ultrasonographic maturation of native arteriovenous fistulae: a follow-up study

BACKGROUND/AIMS

Ideal time needed for arteriovenous fistula (AVF) maturation is still controversial. In this study, we aimed to investigate the natural course of AVF maturation and also investigated the factors affecting AVF maturation.

METHODS

We studied 31 (21M/10F, mean age 55.8 +/- 16.2) chronic renal failure patients. We evaluated the patients with color Doppler ultrasound examination before the fistula operation, at the first day, and at the first, second, third, and sixth months. Radial artery (RA) diameter, flow velocity, flow, resistance index, fistula vein diameter, flow velocity, and flow were measured.

RESULTS

Patency rates at the first post-operative day and the sixth month were 87.1% and 67.1%, respectively. Cephalic vein flow was 451.2 +/- 248.6 mL/min at the first month and 528.6 +/- 316.5 mL/min at the sixth month. Baseline RA diameter was lower in failing fistulas than that of patent fistulas. Failing fistulas were more common in women.

CONCLUSION

Blood flow was enough for hemodialysis at the end of the first month. However, fistula maturation had continued until the end of the study; women and patients with low RA diameter are particularly prone to fistula failure. Therefore, especially in these patients, AVF must be created at least three or four months before the predicted hemodialysis initiation time.

Tunnelled Catheters for the Haemodialysis Patient

Haemodialysis depends upon the establishment of a durable means of vascular access. Although the creation of a successful arterio-venous Fistulae (AVF) is the ideal, this is not always possible or practical. Tunnelled catheters play an important role as an interim/bridge technique for emergency access or while an AVF matures, but may be associated with significant morbidity. The aim of this review is to highlight recent evidence based developments in tunnelled catheters, including methods of placement, complications and possible management strategies.

Steal in Hemodialysis Patients Depends on Type of Vascular Access

OBJECTIVES

To study incidence and severity of steal phenomena in hemodialysis patients and to investigate possible methods for its detection.

METHODS

A questionnaire was composed based on a literature search. A subgroup of patients having steal as identified by the questionnaire was studied using physical examination, arterial blood pressure, skin temperature, digital oxygenation, grip strength and plethysmography. Contralateral arms served as controls.

RESULTS

A cold hand was present in 50% of the patients with a brachiocephalic (BC) arteriovenous fistula (AVF, n = 28) compared to 25% of prosthetic forearm loops (loop, n = 27) and 12% of the radiocephalic (RC, n = 65, p < 0.05) fistulas. Diabetics were at risk for steal (p < 0.001). Intensity of steal was not related to magnitude of access flow. Digital skin temperatures and grip strength were lower in steal hands (p < 0.02). Manual compression of the AVF normalised low digital pressures in steal hands (106 +/- 33 vs 154 +/- 25 mmHg, p < 0.001, contralateral side 155 +/- 21 mmHg).

CONCLUSIONS

Mild to moderate steal symptoms are common in a hemodialysis patient. Individuals with a BC are at a higher risk for developing complaints associated with reduced hand circulation compared to patients with a RC or loop. Low finger pressures in the presence of steal symptoms are usually reversible.

Influence of autologous arteriovenous fistula on the blood supply to the hand in very elderly hemodialyzed patients

INTRODUCTION

Arteriovenous fistula (AVF) creation for hemodialysis (HD) could predispose to local arterial insufficiency of the hand (steal syndrome). Patients with diabetes mellitus, peripheral arterial disease and elderly patients tend to have a higher risk of hand ischemia.

PURPOSE AND METHODS

To estimate the influence of AVF on the blood supply to the hands in the elderly population and to identify steal syndrome cases by non-invasive diagnostics (finger photoplethysmography (PPG), pulse volume recording (PVR), Doppler analysis and pulseoxymetry). The evaluation was carried out in 25 random patients (10 females, 15 males) >75 yrs of age (79.6 +/- 3.87 yrs), whose functioning autologous AVFs had been placed at least 1 month previously.

RESULTS

Mean PPG and PVR amplitudes did not differ in statistical analysis (p > 0.05) between hands with and without an AVF. One patient (4%) with end-to-side anastomosis was diagnosed with steal syndrome (typical manifestation confirmed in PPG, Doppler and pulseoxymetry). Two other patients with high brachio-cephalic anastomosis presented subclinical steal syndrome (only low PPG and PVR).

CONCLUSIONS

Even in the very elderly, AVF creation should be considered due to a lesser influence on the blood supply to the hands. Non-invasive diagnostics used by us seemed to be useful in identifying steal syndrome after AVF creation.

Contrasting Effects of Varicose Vein Surgery on Endothelial-dependent and -independent Cutaneous Vasodilation in the Perimalleolar Region

OBJECTIVES

To evaluate the effects of varicose vein surgery on cutaneous microvascular perfusion and vasodilator responses to acetylcholine (Ach) and sodium nitroprusside (SNP) in the gaiter area of patients with great saphenous vein insufficiency.

METHODS

Twenty-nine patients with isolated great saphenous vein incompetence attended three study mornings (before surgery, and 6-8 weeks and 6 months after sapheno-femoral ligation+partial stripping) during which cutaneous microvascular responses were measured in the supine and standing positions using laser Doppler fluximetry (LDF) combined with incremental-dose iontophoretic administration of endothelial-dependent (Ach) and -independent (SNP) vasodilators.

RESULTS

Varicose vein surgery had no significant effect on baseline cutaneous perfusion or the microvascular response to Ach: e.g. peak vasodilator responses to the 1000 microC stimulus were mean 58 SEM 7, 64 SEM 6 and 65 SEM 7PU on the pre-operative, 6-8 weeks and 6 months assessments. In contrast, the corresponding responses to SNP were significantly increased following surgery: e.g. at 2000 microC, mean 63 SEM 9, 142 SEM 4 and 157 SEM 9PU (p<0.0001) in the upright position.

CONCLUSIONS

Sapheno-femoral ligation and partial stripping in patients with great saphenous vein insufficiency improves endothelial-independent cutaneous vasodilator function at the gaiter area, which may at least partly explain the benefits of surgery in reducing the risk of venous ulceration.

Demands for vascular access in a renal dialysis unit: Implications for a regional vascular unit

BACKGROUND

The development of regional dialysis units and the expanding indications for dialysis has led to increased demand for vascular access surgery. Consequently, the provision and maintenance of access, and the management of related complications has created a considerable burden on vascular surgical units in hospitals providing renal replacement therapy (RRT).

AIMS

The objectives of our study were to review our experience with a variety of vascular access modalities for haemodialysis and to quantify the associated surgical workload.

METHODS

We reviewed our experience in a consecutive group of dialysis patients who had access surgery for RRT in a regional hospital setting.

RESULTS

Between January 1995 and January 2000, 69 patients entered the long-term dialysis programme in the Mid-Western region (population = 320,000). Of the 158 procedures performed, 138 (87%) were for access creation, and 20 (13%) related to access revision procedures. Twenty patients (29%) developed a total of 30 access related complications. Vascular access procedures accounted for 10% of the vascular surgical workload (1598 procedures) in the five-year period.

CONCLUSION

Vascular access is an important part of the haemodialysis services and surgical expertise should be available at local level to cope with likely demand.

Endovascular versus Surgical Preemptive Repair of Forearm Arteriovenous Fistula Juxta-Anastomotic Stenosis: Analysis of Data Collected Prospectively from 1999 to 2004

Surgery is the traditional treatment for juxta-anastomotic stenoses in forearm arteriovenous fistulas (AVF), but percutaneous transluminal angioplasty (PTA) is a suitable alternative. No prospective comparative trials between the two have been reported to date, however. A retrospective analysis of prospectively, concurrently collected data was performed to compare the outcome and cost of surgery and PTA in the preemptive repair of juxta-anastomotic stenosis in lower forearm AVF. Sixty-four AVF with >50% venous juxta-anastomotic stenosis were considered: 21 were treated surgically (11 proximal neo-anastomosis and 10 polytetrafluoroethylene interposition graft) and 43 by PTA. After treatment, AVF were monitored by quarterly ultrasound dilution access blood flow measurement. End points were restenosis and procedure failure rate (re-intervention by another technique or access loss), and determinants were analyzed using Cox hazard model. Initial procedural success was 100% for surgery and 95% for PTA (P = 0.539). Restenosis rate was 0.168 and 0.519 events/AVF-year for surgery and PTA, respectively (P = 0.009). The type of procedure was the only variable that was significantly associated with restenosis, the adjusted relative risk being 2.77-fold higher (95% confidence interval 1.07 to 7.17; P = 0.036) after PTA than surgery. The procedure failure rate was 0.110 and 0.097 events/AVF-year for surgery and PTA, respectively (P = 0.736). The cost profile also was similar for the two procedures. This prospective comparative study confirms a higher restenosis rate after PTA than surgery, but with strict surveillance for restenosis, the two procedures show similar assisted primary patency and cost, suggesting that they should be considered equally valid, complementary alternatives in the preemptive treatment of juxta-anastomotic stenosis in forearm AVF.

MDCT angiography for evaluation of the complete vascular tree of hemodialysis fistulas

OBJECTIVE

The purpose of our study was to assess the clinical feasibility of MDCT angiography for evaluating hemodialysis arteriovenous fistulas (AVFs).

MATERIALS AND METHODS

MDCT angiography of the complete vascular trees of 36 failing AVFs or AVF-related complications (20 native and 16 polytetrafluoroethylene graft AVFs) was reviewed. The numbers and degrees of stenoses at the anastomoses, graft loops, and draining and central veins and the presence of aneurysms or thrombosis were recorded. Wilcoxon's signed rank test was used to compare the findings of MDCT angiography with those of digital subtraction angiography (DSA) (n = 10), surgery (n = 22), or both (n = 4) performed within 2-6 days. Kappa statistics were used to correlate the clinical feasibility of MDCT angiography assessed by two reviewers.

RESULTS

Among the 14 AVFs examined with both MDCT angiography and DSA, no significant difference was seen in the detection and grading (p = 0.317 to > 0.999) of stenoses at various segments of the entire vascular tree. Among the 36 AVFs examined, MDCT angiography also showed no significant difference from DSA or surgery in revealing vascular stenoses, aneurysms, and thromboses from the supplying artery to central veins (p = 0.317 to > 0.999). Overall, the sensitivity, specificity, positive and negative predictive values, and accuracy of MDCT angiography in lesion detection were 98.7%, 97.5%, 98.8%, 97.2%, and 98.3%, respectively. High image quality with superb interobserver correlation (kappa = 0.809 to > 0.999) validated the clinical feasibility of MDCT angiography for assessing AVFs.

CONCLUSION

MDCT angiography is clinically feasible for evaluating the complete vascular tree of failing AVFs and in showing uncommon complications, including brachial aneurysms and central vein lesions.

Primary and Secondary Patency Rates and Complications of Upper Extremity Arteriovenous Fistulae Created for Hemodialysis

The types of fistulae used and their complication rates are important for the hemodialysis patients. We aimed to compare retrospectively the primary and secondary patency rates and complications of upper extremity arteriovenous fistulae. Between 1984 and 2005, a total of 1,233 upper extremity arteriovenous fistulae were created in 920 patients. The mean age was 42 +/- 21 years. The fistulae were divided into the 3 groups; 588 radiocephalic, 205 brachiocephalic, and 127 were created by polytetrafluoroethylene graft. The fistulae types were evaluated with regard to their primary-secondary patency rates and complications. There was a significant difference with regard to development of thrombosis in radiocephalic group compared to other two groups, respectively, p = 0.0122, p = 0.0091. In brachiocephalic fistulae group, edema and steal phenomenon were statistically significant (p < 0.0001). The aneurysm formation was statistically significant in polytetrafluoroethylene fistulae graft group (p < 0.0001). During 6 months, 2 and 5 years period, while primary patency rate was higher in three fistulae types, in radiocephalic fistulae both primary and secondary fistulae patency rates were lower (p < 0.05). To create successful arteriovenous fistulae with long-term patency, appropriate veins of patients should be carefully preserved; thus initially a distal site should be preferred, and in case of failure the next fistulae should be created proximally. In case of failure of forearm fistulae, primary fistulae with autogenous veins should be tried at the upper arm first, and if this also fails, fistulae formation with synthetic grafts should be considered.