Effect of preoperative sonographic mapping on vascular access outcomes in hemodialysis patients

Effect of Chinese herbal fomentation on arteriovenous fistula maturation

OBJECTIVES

The study objectives were to examine the effects of Chinese herbal fomentation on radiocephalic arteriovenous fistula (AVF) maturation.

METHODS

All patients' preoperative evaluation, operative procedure, and follow-up information records were reviewed to identify patients undergoing radiocephalic AVF procedures for maintenance hemodialysis. All patients underwent preoperative vessel ultrasound. The ultrasound examinations were repeated every 2 months after the operative procedure. From the day after the operation, the forearm of the patient is fomented with a mixture of Dan Shen and Hong Hua in dry powdered form dissolved in fresh warm water. The fomentation lasted for 60 minutes, once a day for 28 consecutive days.

RESULTS

Sixty-four (64) specific access site operations were yielded in 62 patients for analysis. Forty-nine (49; 76.6%) of the 64 fistulas were considered sonographically mature and 15 (23.4%) were deemed sonographically immature. The sonographically mature fistulas (n=46) that were suitable for puncture had blood flow of 655±132 mL/minute, and venous diameter of 4.5±0.3 mm. The most frequent complication was thrombosis before first use, which accounted for 6 AVFs failures to mature (0.16 per patient-year). There were two hospitalizations for fistula-related bacteremia in the group (0.05 per patient-year).

CONCLUSIONS

The Chinese herbal fomentation reduced the frequency of early thrombosis of new AVFs and was accompanied by an increase in the proportion of AVFs that were suitable for dialysis.

Arteriovenous graft placement in predialysis patients: a potential catheter-sparing strategy

BACKGROUND

When predialysis patients are deemed unsuitable candidates for an arteriovenous fistula, current guidelines recommend waiting until just before or after initiation of dialysis therapy before placing a graft. This strategy may increase catheter use when these patients start dialysis therapy. We compared the outcomes of patients whose grafts were placed before and after dialysis therapy initiation.

STUDY DESIGN

Retrospective analysis of a prospective computerized vascular access database.

SETTING & PARTICIPANTS

Patients with chronic kidney disease receiving their first arteriovenous graft (n = 248) at a large medical center.

PREDICTOR

Timing of graft placement (before or after initiation of dialysis therapy).

OUTCOME & MEASUREMENTS

Primary graft failure, cumulative graft survival, catheter dependence, and catheter-related bacteremia.

RESULTS

The first graft was placed predialysis in 62 patients and postdialysis in 186 patients. Primary graft failure was similar for pre- and postdialysis grafts (20% vs 24%; P = 0.5). Median cumulative graft survival was similar for pre- and postdialysis grafts (365 vs 414 days; HR, 1.22; 95% CI, 0.81-1.98; P = 0.3). Median duration of catheter dependence after graft placement in the postdialysis group was 48 days and was associated with 0.63 (95% CI, 0.48-0.79) episodes of catheter-related bacteremia per patient.

LIMITATIONS

Retrospective analysis, single medical center.

CONCLUSION

Grafts placed predialysis have primary failure rates and cumulative survival similar to those placed after starting dialysis therapy. However, postdialysis graft placement is associated with prolonged catheter dependence and frequent bacteremia. Predialysis graft placement may decrease catheter dependence and bacteremia in selected patients.

Access Monitoring Does Not Really Improve Outcomes

It is widely accepted that hemodialysis access monitoring combined with preemptive percutaneous transluminal angioplasty (PTA) improves outcomes. The many studies that have evaluated monitoring during the last decade provide an opportunity to examine whether this hypothesis is valid. Because synthetic grafts are more likely than autogenous arteriovenous fistulas to benefit from monitoring, this review is restricted to grafts. Recent studies show that monitoring does not accurately predict graft thrombosis or failure, nor does it prolong graft life. However, monitoring can reduce thrombosis, and thereby reduce access-related hospitalizations and use of central venous dialysis catheters. Because preemptive PTA is expensive, however, monitoring does not reduce the cost of access-related care. The limited benefit that monitoring provides emphasizes the urgent need to develop better approaches to solving the problem of graft thrombosis and failure.

Infectious complications following conversion to buttonhole cannulation of native arteriovenous fistulas: a quality improvement report

BACKGROUND

Constant-site or buttonhole cannulation of native arteriovenous fistulas (AVFs) has gained in popularity compared with rope-ladder cannulation. However, cannulating nonhealed skin might increase the risk of (AVF-related) infectious events, as suggested by small reports.

STUDY DESIGN

Quality improvement report.

SETTING & PARTICIPANTS

All patients on in-center hemodialysis therapy using a native AVF from January 1, 2001, to June 30, 2010.

QUALITY IMPROVEMENT PLAN

Shift to buttonhole cannulation between August 2004 and January 2005. Because the infectious event rate increased after the shift, educational workshops were held in May 2008 for all nurses, with review of every step of buttonhole protocol.

OUTCOMES

Infectious events (unexplained bacteremia caused by skin bacteria and/or local AVF infection) and complicated infectious events (resulting in metastatic infection, death, or AVF surgery) were ascertained during 4 periods: (1) rope-ladder technique in all, (2) switch to buttonhole, (3) buttonhole in all before workshops, and (4) buttonhole in all after workshops.

RESULTS

177 patients (aged 70.4 ± 11.5 years) with 193 AVFs were analyzed, including 186,481 AVF-days. 57 infectious events occurred (0.31 events/1,000 AVF-days). The incidence of infectious events increased after the switch to the buttonhole method (0.17 [95% CI, 0.086-0.31], 0.11 [95% CI, 0.0014-0.63], and 0.43 [95% CI, 0.29-0.61] events/1,000 AVF-days in periods 1, 2, and 3, respectively; P = 0.003). This reached significance during only the second full year of buttonhole cannulation. During period 4, the incidence tended to decrease (0.34 events/1,000 AVF-days). Complicated infectious events (n = 12) were virtually restricted to period 3 (n = 11; 0.153 [95% CI, 0.076-0.273] events/1,000 AVF-days), with a significant decrease in period 4 (n = 1; 0.024 [95% CI, 0.001-0.118] events/1,000 AVF-days; RR for period 3 vs period 4, 6.37 [95% CI, 1.09-138.4]; P = 0.04).

LIMITATIONS

Observational partly retrospective design.

CONCLUSION

Intensive staff education regarding strict protocol for the buttonhole procedure was associated with a decrease in infectious events.

Routine preoperative venous and arterial mapping increases both, construction and maturation rate of upper arm autogenous arteriovenous fistulae

OBJECTIVE

To test the hypothesis that routine preoperative mapping and transposed brachial-basilic vein fistula (TBBVF) increases arteriovenous fistulae (AVFs) construction rates, without altering maturation rate.

PATIENTS

Over a 4-year period, 709 vascular accesses were performed, including 467 AVFs (radial-cephalic fistula [RCF], n = 217, brachial-cephalic fistula [BCF], n = 139, TBBVF, n = 111) and 251 prosthetic grafts. During the last 2 years, preoperative mapping was performed routinely by means of ultrasound, and TBBVFs were preferentially used over arteriovenous grafts (AVGs).

RESULTS

Over the study, construction rate of upper arm AVF increased significantly from 12% to 53% and use of prosthetic grafts decreased from 55% to 19% (P < .001). Maturation rate of RCFs, BCFs, and TBBVFs during the first part of the study was 75%, 50%, and 30% (P = .003), compared to 79%, 82%, and 86% (P = .43), respectively, during the second part.

CONCLUSIONS

Routine preoperative upper extremity mapping with ultrasound increases not only AVF construction rate, but also their maturation likelihood.

Decreased cumulative access survival in arteriovenous fistulas requiring interventions to promote maturation

BACKGROUND AND OBJECTIVES

New arteriovenous fistulas (AVF) are frequently unsuitable for hemodialysis because of AVF nonmaturation. Aggressive endovascular or surgical interventions are often undertaken to salvage nonmaturing AVFs. The effect of early interventions to promote AVF maturation on subsequent long-term AVF outcomes is unknown.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We evaluated 173 hemodialysis patients from two academic centers who received a new AVF. Of these, 96 (56%) required no further intervention, 54 (31%) required one intervention, and 23 (13%) required two or more interventions to achieve suitability for dialysis. We calculated AVF survival and frequency of postmaturation interventions in each group.

RESULTS

Cumulative AVF survival (access cannulation to permanent failure) in patients with two or more versus one versus zero interventions before maturation was 68% versus 78% versus 92% at 1 year, 57% versus 71% versus 85% at 2 years, and 42% versus 57% versus 75% at 3 years. Using Cox regression analysis with interventions before maturation, age, sex, race, diabetes, peripheral vascular disease, access site, and obesity in the model, intervention before maturation (two or more) was the only factor associated with cumulative AVF survival. The number of interventions required to maintain patency after maturation was 3.51 ± 2.20 versus 1.37 ± 0.31 versus 0.76 ± 0.10 per year in patients with two or more versus one versus zero interventions before maturation.

CONCLUSIONS

Compared with AVF that mature without interventions, AVF that require interventions have decreased cumulative survival and require more interventions to maintain their patency for hemodialysis.

Improving Dialysis Access: Regional Anesthesia Improves Arteriovenous Fistula Prevalence

An autologous arteriovenous (AV) fistula is the preferred form of angioaccess for chronic hemodialysis. A prospective study was carried out to evaluate the potential of regional anesthesia to improve AV fistula prevalence. One hundred ninety-three patients underwent preoperative duplex ultrasound evaluation over a 14-month period. The qualification of each patient to receive either an autologous AV fistula or a prosthetic graft was based on specific sonographic criteria. Patients scheduled for placement of a graft received an ultrasound-directed supraclavicular brachial plexus block, which produces dense sympathetic blockade. After the regional block, those patients who met criteria for primary fistula construction on repeat ultrasound received a fistula instead of a graft. Of 62 patients scheduled to receive an AV graft, 23 or 37 per cent were recruited to receive a fistula instead. The outcome of the recruited fistulas was compared with the 121 planned fistulas. There was no statistically significant difference in primary failure rate (4.3 vs 5.8%). The recruited fistulas had a shorter average maturation time, 83 ± 48 versus 132 ± 82 days ( P = 0.023). Within the study population, functioning fistula prevalence was increased from 61.7 to 79.8 per cent. Regional anesthesia and immediate preoperative ultrasound is a useful strategy for increasing fistula prevalence.

Comparison of radiocephalic fistulas placed in the proximal forearm and in the wrist

Non-maturation is a common problem in patients receiving an arteriovenous fistula. The first vascular access choice is a distal radiocephalic fistula (dRCF) at the wrist. Patients with a failed dRCF or with vessels unsuitable for dRCF, the recommendation is to place a brachiocephalic fistula in the upper arm. Proximal forearm radiocephalic fistulas (pRCF) are created infrequently, but may permit a second forearm fistula before proceeding to the upper arm. The goal of the present study was to compare the outcomes of them. We retrospectively analyzed a computerized access database to compare the outcomes of 19 RCF and 39 dRCF placed during a 6-month period. The baseline characteristics were similar, except those with a pRCF were more likely to have previous access and be male. Primary failure (non-maturation) was lower for pRCF than dRCF (32 vs. 59%, p = 0.05); and excluding secondary failures, cumulative fistula survival was similar (92 vs. 86% at 1 year and 74 vs. 76% at 2 years, p = 0.56). pRCF may be an attractive alternative to a brachiocephalic fistula in patients who cannot receive a dRCF. pRCF has a lower non-maturation rate than that of a dRCF, and a comparable cumulative survival once it is used successfully for dialysis.

Duplex sonography in the planning and evaluation of arteriovenous fistulae for haemodialysis

This paper describes how to perform duplex sonography in the planning and evaluation of arteriovenous fistulae in haemodialysis patients, discusses its roles in these settings, and presents a review of commonly encountered complications.

Who should be referred for a fistula? A survey of nephrologists

BACKGROUND

There is marked variation in the use of the arteriovenous fistula (AVF) across programmes, regions and countries not explained by differences in patient demographics or comorbidities. The lack of clear criteria of who should or should not get a fistula may contribute to this, as well as barriers to creating AVFs.

METHODS

We conducted a survey of Canadian and American nephrologists to assess the patient variables considered to determine the timing and type of access requested. Perceived barriers and absolute contraindications to access were also collected.

RESULTS

An immediate referral for a fistula was more highly preferred when patients are <65 years old, have minimal comorbidities or have no history of failed accesses. In older patients, and in those with increased comorbidities or a previously failed fistula, US nephrologists selected arteriovenous grafts as an alternative to the fistula, while Canadian nephrologists selected primarily catheters. Referral for vascular mapping was more common in the USA than in Canada. Gender did not influence the timing or the type of access. Perceived barriers to establishing a mature fistula included patient refusal for creation (77%) or cannulation (58%), delay in decision regarding dialysis modality (71%), wait time for surgical creation (55%) and high failure-to-mature rate (52%). We found that 27% of Canadian and 43% of American nephrologists indicated no absolute contraindications for permanent vascular access.

CONCLUSIONS

This study demonstrated marked variability in timing and criteria used to select patients for referral for a vascular access between nephrologists practicing within Canada and the USA. Establishing minimal eligibility criteria for fistulae is an important area of future research.

Arteriovenous fistulas constructed using side-to-side anastomosis with ligation and division of distal venous arm; a tertiary care hospital experience

BACKGROUND AND OBJECTIVE

The rising prevalence of end-stage renal disease has added to the demands of renal replacement therapy in the form of hemodialysis (HD) in lieu of unmitigated needs of renal transplants. The best available angioaccess for HD is the autogenous arteriovenous fistula. Many techniques for arteriovenous anastomosis have been reported, but there is dearth of data which study the side-to-side arteriovenous anastomosis with concomitant ligation and division of the distal venous arm. This study aimed to describe the clinical outcome of the fistulae constructed with this particular technique.

METHODS

It is a descriptive and retrospective review in which all patients who underwent the operation with this particular technique in a certain time period were included. The data entry and analysis was done using SPSS 15. Only descriptive statistics are used. Demographic details, primary patency, end point patency and fistula survival were calculated.

RESULTS

There were 77 patients, 61 males and 16 females. Radiocephalic arteriovenous anastomosis was constructed in 65 patients, brachiocephalic in 11 patients and brachiobasilic in one patient. Primary patency was 96.1% and end point patency was 90.9% with a median survival of 44 weeks at the end point.

CONCLUSION

This particular technique of fistula construction has excellent patency rates, fistula survival and lesser complications when compared to what has been reported for other methods. It is therefore recommended that the technique of angioaccess reported in this study may be considered as a first option.

Focused vascular access education to reduce the use of chronic tunneled hemodialysis catheters: results of a network quality improvement initiative

Tunneled hemodialysis catheters (TDCs) carry the highest mortality risk for chronic hemodialysis patients of any access modality. Recent data have emphasized that mortality risk decreases when these devices are discontinued. Herein, we present the results of a gap-reduction assisted catheter elimination strategy that Network 7 employed as its quality improvement initiative to reduce the use of TDCs. Hemodialysis facilities with high catheter rates (>90 days) were identified. Interventions included focused vascular access education, monthly follow-up and site visits to assist the facility catheter reduction program. The "goal" of interventions was defined as the gap-reduction of 50% from the baseline catheter rate to the Network mean plus sustainability of catheter reduction for at least 3 consecutive months. Fifteen facilities (n = 891) were identified with high catheter rates (31.5 +/- 5.3%) in May 2006. Interventions resulted in a catheter reduction to 12.2 +/- 8.5% in May 2007 (p = 0.0001). Five of the 15 facilities (n = 280) achieved the goal (preintervention = 31.7 +/- 5.3%, postintervention = 8.7 +/- 2.8%, p = 0.001). In May 2007, eight additional facilities (n = 438) with high catheter rates (31.7 +/- 7.8%) were added to the 10 that failed to achieve the goal previously. Interventions employed in these 18 facilities (n = 1,049) resulted in catheter reduction in all (preintervention = 31.5 +/- 5.5%, postintervention = 16.2 +/- 5%, p = 0.01). Five of these 18 met the goal (preintervention = 32 +/- 8%, postintervention = 5.9 +/- 4.3%). Overall, all 23 facilities (n = 1,329) demonstrated catheter reduction postintervention (preintervention = 31.6 +/- 6%, postintervention = 13.9 +/- 6%, p = 0.001), and 10/23 (43%) met the project goal (preintervention = 31.9 +/- 6%, postintervention = 7.3 +/- 4%, p = 0.002). Medical director's involvement had a positive impact in achieving the goal (p = 0.003). The presence or absence of a vascular access coordinator did not affect catheter reduction. The results of this analysis reveals that an organized approach implemented by an ESRD Network can have a significant impact in reducing catheter use.

Small dose contrast venography as venous mapping in predialysis patients

PURPOSE

This study was designed to evaluate radiocontrast-induced nephrotoxicity (RIN), and the image quality and findings of venography using small doses of radiocontrast as a venous mapping method in pre-dialysis patients.

METHODS

Twenty-eight patients with stage 4 and 5 chronic kidney disease underwent arm venography with 10-15 ml of dilute contrast medium. Image quality, venographic findings and glomerular filtration rate (GFR) before and after the procedure were evaluated.

RESULTS

Mean GFR was 19.3+/-5.8 ml/min/1.73 m2 (7-30 ml/min/1.73 m2). Image quality of venography in the forearm and upper arm veins was good in all patients. Central veins were visualized well in 26 (92.8%) patients. Eight (28.5%) patients showed cephalic veins inadequate for creation of radiocephalic arteriovenous fistula (AVF) because of occlusion or small diameter veins. There was no significant difference in GFR between the pre- and post-study (19.3+/-5.8 vs. 19.2+/-6.2 ml/min/1.73 m2, p=0.693). RIN developed (GFR: 17 to 13 ml/min/1.73 m2) in only one patient but without sequelae, and the GFR completely recovered to baseline level 7 days after the study.

CONCLUSION

Small dose venography is safe and effective for venous mapping in pre-dialysis patients.

Preoperative mapping for haemodialysis access surgery with CO(2) venography of the upper limb

OBJECTIVE

This study aims to evaluate the impact of CO(2) venography on the planning and outcome of native arteriovenous fistula (AVF) creation.

METHODS

Records of patients who underwent CO(2) venography prior to access surgery between January 2000 and December 2008 were reviewed. CO(2) venography was performed selectively in chronic kidney disease (CKD) in stage IV-V patients without suitable veins on clinical examination. Findings at surgery were compared to CO(2) venography images. Patency of AVFs was analysed by the Kaplan-Meier method. Differences in outcome of maturation were compared using a chi(2) test.

RESULTS

A total of 209 CO(2) venograms were obtained in 116 patients. In 89 patients (77%), 101 AVFs (21 forearm AVF (21%) and 80 elbow AVF (79%) were created. Surgical findings corresponded with CO(2) venography findings in 90% of patients. In 10 cases (10%), access was created at the elbow despite a patent forearm cephalic vein on CO(2) venography (n = 2) or access was attempted with a vein which was thought to be unsuitable on CO(2) venography (n = 8). Maturation rate of the latter was 50% (4/8) vs. 88% (80/91) for AVFs created with veins considered usable (P = 0.004). The overall maturation rate was 84% with 1-year primary, assisted primary and secondary patency rates of 63%, 70% and 71%, respectively.

CONCLUSION

CO(2) venography is a useful tool for venous mapping prior to vascular access surgery, resulting in an overall maturation rate of 84% and good patency rates.

Epidemiology and blood flow surveillance of the native arteriovenous fistula: a review of the recent literature

Vascular access placement is a key management issue for hemodialysis patients. Despite being well regarded as the access of first choice, the native arteriovenous fistula (AVF) remains underutilized in the United States. The first part of this review examines recent epidemiology studies addressing patient factors associated with the use of the synthetic arteriovenous graft as opposed to the native fistula. Female gender and older age are consistently associated with a higher frequency of graft use. Diabetes, peripheral vascular disease, and body mass index were associated with graft use in some but not all of the studies. Recent evidence also suggests an independent survival advantage for patients dialyzing via native fistulae especially for infection-related mortality. The second part reviews evidence surrounding the recommendations for blood flow surveillance of the native fistula. The hemodynamic features of the native fistula are examined and differences from synthetic grafts are highlighted. Clinical studies assessing the use of blood flow surveillance to prevent the sudden thrombosis of native fistulae are reviewed. Blood flow thresholds for further investigation are yet to be determined definitely for AVF and randomized studies should be performed to assesses the impact on AVF thrombosis rates.

Fistula salvage by endovascular therapy

Fistulas are considered superior to synthetic grafts as a hemodialysis vascular access; however, fistulas are not without problems. To maximize the number of fistulas being used in prevalent patients, it is important to have a program designed to salvage early failures or fistulas that fail to mature and those that become dysfunctional during the course of usage. Endovascular techniques have proven to be very effective in the management of both of these problems. These fistulas should be aggressively evaluated and treated because treatment carries with it a high expectation of successful salvage of what would have otherwise been an abandoned access.

Vascular mapping: does it help to maximize fistulae placement?

The population of patients with ESRD in the United States is progressively increasing, with hemodialysis (HD) as the major mode of renal replacement therapy. The National Kidney Foundation's Dialysis Outcomes and Quality Initiative and the Fistula First Initiative recommend increasing the use of arteriovenous fistulae (AVF) in both incident and prevalent hemodialysis patients. One measure proposed is the use of pre-operative vascular mapping to assess the upper extremities for the presence of suitable vessels prior to the surgical creation of an AVF among both pre-dialysis CKD and ESRD patients on HD. This article aims to review the literature on vascular mapping, including the various techniques; their advantages and disadvantages; and whether they help to maximize the AVF creation rate as well as increase the use of AVF in the HD population.

Salvage of Inaccessible Arteriovenous Fistulas in Obese Patients: A Review of 132 Brachiocephalic Fistulas

The two main factors leading to a functional fistula are maturity and accessibility. The aim of this review was to describe a technique of superficialization for inaccessible brachiocephalic fistulas, and to identify the patients that benefit from superficialization. One hundred and thirty-two brachiocephalic arteriovenous fistulas developed from November 2003 to December 2006 were reviewed for primary maturation. In the mature group, patients were evaluated for fistula accessibility. Inaccessible fistulas were selected for superficialization via our technique of vein mobilization using small skip incisions. Analysis of superficialized and nonsuperficialized groups included age, demographics, and comorbidities. Ninety-nine patients were in the mature group, and 33 in the immature group; primary nonmaturation was 25 per cent. Analysis within the mature group was between nonsuperficialized (n = 81) and superficialized (n = 18) patients. The superficialized group had less hypertension (83% vs 98%, P < 0.05), significantly higher BMI (31 vs 27, P < 0.05), and was mostly female (78% vs 49%, P < 0.05). All superficialized fistulas accommodated successful hemodialysis postoperatively. To conclude, patients with mature but inaccessible fistulas were salvaged by superficialization. This population had significantly higher BMI, less hypertension, and female prevalence. Identifying these patients is important because salvage of their fistula can prevent premature progression to alternate autogenous arteriovenous access procedures.

Benefits of Intraoperative Digital Subtraction Angiography in Primary Arteriovenous Fistula Creation

Digital subtraction angiography (DSA) is an ideal procedure for improving vascular surgery results, not yet in use for arteriovenous fistula (AVF) creation. In a prospective study, the practicability and benefits of intraoperative completion DSA (CDSA) for this purpose were investigated. When the arteriovenous anastomosis was completed and clinically judged as running, DSA via percutaneous or open-site puncture was conducted. Findings and consequences were prospectively documented. From July 2005 to September 2006 a primary AVF was created in 54 patients. Fifty of these could be included in the study (68, 39–91 yrs). In 44 a forearm fistula, and in six patients an elbow fistula was newly created. In two cases we were unable to insert a cannula into the A. brachialis (study escape). In the remaining 48 cases, CDSA visualized afferent artery, anastomosis and draining vein. No complications occurred associated with CDSA; 3.5, 2–12 ml, contrast agent were required per patient. In 13 cases, CDSA revealed problems with the AVF that could be corrected immediately: the vein was freed from restraining soft tissue (n=4), a stealing venous branch was ligated (n=6), transluminal thrombectomy was conducted (n=1) or anastomosis was newly created (n=3). AVF could be successfully created proven by ongoing dialysis in 30 cases, and in eight cases as demonstrated by clinical and sonographic evaluations, resulting in a primary 1-yr patency rate of 79.2%. CDSA in AVF surgery is practicable and reveals conditions that can be corrected immediately, thus improving surgical outcome. Long since standard in other areas of vascular surgery, CDSA should become a routine procedure in AVF creation.

Preoperative Evaluation for Vascular Access Creation

In an effort to increase the prevalence of arteriovenous fistulae (AVF), ultrasound vessel mapping (USVM) and upper extremity venography (UEV) have been suggested; however, the effectiveness of their combined use remains unknown. We studied the effect of such a combined protocol on arteriovenous (AV) access type change compared with physical examination alone. Consecutive patients with chronic kidney disease ( n = 137) after an initial estimation of the AV access type, based on physical examination, had USVM and UEV to detect vascular pathology that could potentially alter the original plan. USVM changed the preoperative plan in 31 (22.6%) patients; this was 36.7% ( n = 18) in diabetics compared with 14.8% ( n = 13) in nondiabetics ( p < .001). Patients for whom USVM changed the type of planned AV access had been on hemodialysis significantly longer (2.7 years vs 0.9 years; p < .001). Venography identified 18 patients with central vein stenosis that led to a site change in 12 of them. Significant venous stenosis in patients with a history of two or more central catheters placed and patients without such a history was 93% and 1%, respectively. In eight patients, intraoperative findings dictated AV graft placement or creation of a central AVF. The original plan was revised in 31%, and this rate was similar for distal AVF, central AVF, and AV grafts (38%, 26%, and 43%, respectively; all p > .05). The 30-day patency rate was 92.2%. A significant proportion of patients have vascular pathology severe enough to alter the access type as suggested by physical examination alone. USVM should be routinely performed, whereas UEV should be selectively performed in patients with a history of surgery or instrumentation of their central veins.

Increased hemodialysis catheter use in Canada and associated mortality risk: data from the Canadian Organ Replacement Registry 2001-2004

BACKGROUND AND OBJECTIVES

The 1999 Canadian vascular access guidelines recommend the fistula as the access of choice. The study describes the trends in hemodialysis access use, variation among provinces, and the association with mortality from 2001 to 2004.

DESIGN, SETTING, PARTICIPANTS AND MEASUREMENTS

An observational study of adult patients registered in Canadian Organ Replacement Registry on hemodialysis. Access trends were examined among incident and prevalent hemodialysis patients adjusted for age, sex, body mass index, late referral, race, smoking status, province, etiology of end-stage renal disease, and comorbidities. Cox proportional hazard regression analysis was used to analyze risk for death for patients followed to December 31, 2005.

RESULTS

From 2001 to 2004, incident catheter use increased from 76.8% to 79.1%, fistulas decreased from 21.6% to 18.6%, and grafts remained between 2.1% to 2.6%. Prevalent catheter use increased from 41.8% to 51.7%, and fistulas and grafts decreased from 46.8% to 41.6% and 11.4% to 6.7%, respectively. There was significant variation in incident and prevalent fistulae use among the provinces. Adjustment for differences in patient characteristics did not change these trends. Incident catheter use was associated with a 6 times greater risk of death compared with fistula or graft use combined.

CONCLUSIONS

In Canada there has been a decrease in fistulae and grafts with a subsequent increase in catheters that is not explained by changes in patient characteristics. Vascular access use varied by province, suggesting differences in practice patterns. Because incident catheter use was associated with increased mortality, urgent measures are needed to develop strategies to decrease catheter use.

Outcomes of brachiocephalic fistulas, transposed brachiobasilic fistulas, and upper arm grafts

BACKGROUND AND OBJECTIVES

An upper arm vascular access is often placed in patients with a failed forearm fistula or with vessels unsuitable for a forearm fistula. The aim of this study was to compare the outcomes of three upper arm access types: brachiocephalic fistulas, transposed brachiobasilic fistulas, and grafts.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A prospective, computerized access database was queried retrospectively to identify the clinical outcomes of upper arm accesses placed in 678 patients at a large dialysis center, including 322 brachiocephalic fistulas, 67 brachiobasilic fistulas, and 289 grafts.

RESULTS

Primary access failures were less common for brachiobasilic fistulas and grafts compared with brachiocephalic fistulas (18%, 15%, and 38%; hazard ratio of brachiocephalic fistulas versus brachiobasilic fistulas 2.76; 95% confidence interval 1.41 to 5.38; P < 0.003). For the subset of patients receiving a brachiocephalic fistula, a multiple variable logistic regression analysis including age, sex, race, diabetes, coronary artery disease, peripheral vascular disease, cerebrovascular disease, prior access, surgeon, arterial diameter, and venous diameter found that only vascular diameters predicted primary failure (P < 0.001). When primary failures were excluded, cumulative access survival was similar for brachiobasilic and brachiocephalic fistulas, but superior to that of grafts. Total access interventions per year were lower for brachiobasilic and brachiocephalic fistulas than for grafts (0.84, 0.82, and 1.87, respectively, P < 0.001).

CONCLUSIONS

Transposed brachiobasilic fistulas may be preferred, due to (1) a lower primary failure rate (similar to grafts), and (2) a lower intervention rate (similar to brachiocephalic fistulas). However, this advantage must be balanced against the more complex surgery.

Upper extremity venous Doppler ultrasound

Ultrasound is the initial imaging modality of choice when evaluating the upper extremity venous system. When sonographic findings are equivocal or nondiagnostic, particularly in evaluating the central deep veins, MR venography or catheter venography correlation may be helpful. Ultrasound provides an accurate, rapid, low-cost, portable, noninvasive method for screening, mapping, and surveillance of the upper extremity venous system.

Avaliação da maturação das fístulas arteriovenosas para hemodiálise pelo eco-Doppler colorido

CONTEXTO: Quando se confecciona uma fístula arteriovenosa para hemodiálise (FAVH) autógena, é necessário que se aguarde a dilatação da veia em questão e o desenvolvimento de volume de fluxo mínimo, fenômeno chamado de maturação. Ainda hoje se discute qual o tempo necessário para ocorrer essa maturação. OBJETIVO: Avaliar a maturação de FAVH utilizando-se critérios ecográficos. MÉTODO: Entre maio de 2004 e 2005, 40 pacientes foram selecionados prospectivamente, sendo 23 homens (57,5%), com média de idade de 17,5±51,3 anos, com indicação de confecção de uma FAVH. Utilizou-se o aparelho Logic III® com transdutor de 10 MHz para a avaliação no pré-operatório e nos 7º, 14º, 21º e 28º dias de pós-operatório. Os critérios para a maturação após a cirurgia foram: veia com diâmetro médio maior que 4 mm e volume de fluxo maior que 400 mL/min. RESULTADOS: O diâmetro médio pré-operatório foi de 3,24±1,43 e 3,71±1,37 mm para fístulas de punho e de cotovelo, respectivamente. O diâmetro final foi de 5,01±0,87 mm para as FAVH de punho (p = 0,006) e de 6,15±1,16 mm para as FAVH de cotovelo (p = 0,95). O volume de fluxo no 7º dia pós-operatório foi de 493,63±257,49 mL/min e 976,33±332,90 mL/min para as FAVH de punho e cotovelo, respectivamente. Ao final do estudo, foi calculado o valor de 556,81±288,42 mL/min nas FAVH de punho (p < 0,05) e de 1031,62±614,812 mL/min nas FAVH de cotovelo. Baseados nos dois critérios, a maturação ocorreu em 57,1% das fístulas de punho e em 100% das fístulas de cotovelo após a 1ª semana. Após 4 semanas, 67,9% das fístulas de punho e 100% das fístulas de cotovelo apresentaram maturação. CONCLUSÃO: A maioria das FAVH de cotovelo apresentou diâmetro e fluxo adequados para punção logo após a 1ª semana de pós-operatório. Para as FAVH de punho, houve melhora progressiva dos padrões de maturação com o passar das semanas, sugerindo que essas FAVH devem ser puncionadas preferencialmente após a 4ª semana de pós-operatório.

Resolved: Fistulas are preferred to grafts as initial vascular access for dialysis. Pro

There is growing concern that the Fistula First Initiative, KDOQI guidelines, and subsequent pressure from the Centers for Medicare and Medicaid Services lack reasonableness regarding likely success for fistula maturation in a heterogeneous, new-onset dialysis population. Here the various positions are examined from multiple perspectives.

Time to symptomatic vascular stenosis at different locations in patients with arteriovenous grafts

Most arteriovenous grafts fail due to irreversible thrombosis, superimposed on hemodynamically significant vascular stenosis. Previous studies observed the highest frequency of stenosis at the venous anastomosis, without addressing the timing of stenosis. The present study quantified time to symptomatic stenosis at different vascular locations, and related it to permanent graft failure. A prospective computerized vascular access database was queried retrospectively to identify 309 hemodialysis patients receiving new upper extremity grafts during a 4-year period at a large dialysis center. For each vascular site we calculated the time to symptomatic stenosis using survival techniques. The cumulative likelihood of symptomatic stenosis at 2 years was 67% for venous anastomotic stenosis, 19% for intra-graft stenosis, 16% for venous outlet stenosis, 13% for central vein stenosis, and 5% for arterial anastomotic stenosis. The cumulative risk of graft failure at 2 years was 40%. Stenosis at the venous anastomosis was twice as likely as cumulative graft failure (hazard ratio [HR] 1.95; 95% confidence interval [CI], 1.65-2.52, p < 0.001). In contrast, intra-graft stenosis was half as likely as cumulative graft failure (HR 0.45; 95% CI, 0.36-0.61, p < 0.001). Central vein stenosis was more likely in patients with a previous ipsilateral catheter compared with those without one (HR 2.40; 95% CI, 1.39-5.58, p = 0.004). Symptomatic stenosis occurs much earlier at the venous anastomosis compared with other vascular sites. Moreover, preexisting ipsilateral internal jugular dialysis catheters more than double the risk of central vein stenosis.

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.

Hemodialysis arteriovenous fistula patency revisited: results of a prospective, multicenter initiative

BACKGROUND AND OBJECTIVES

Vascular access standards are predominantly based on older, single-center reports; however, the hemodialysis population has changed dramatically and primary arteriovenous fistula failure is a huge problem. This prospective, multicenter study used standardized definitions to analyze patency rates and potential risk factors that affect functional patency and late arteriovenous fistula functionality.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Eleven centers participated in a guidelines implementation program. All new permanent vascular accesses were included. Patency and functional patency, defined as access survival from creation and from first dialysis use, respectively, were calculated using Kaplan-Meier analysis. Risk factors for primary functional patency loss (intervention-free interval) and secondary failure (abandonment) were determined using regression models.

RESULTS

A total of 491 arteriovenous fistulas were placed in 395 patients. Six-, 12-, and 18-mo secondary patency and functional patency were 75 +/- 2.0, 70 +/- 2.3, and 67 +/- 2.7% and 90 +/- 1.9, 88 +/- 2.2, and 86 +/- 2.7%, respectively. Primary failure rate was 40%. Thrombosis rate was 0.14 per patient-year. Diabetes and arteriovenous fistula surveillance were significantly associated with primary functional patency loss. Preoperative duplex was inversely related to secondary failure. The secondary failure rate per hospital varied from 0 to 39%.

CONCLUSIONS

This study showed a marked difference between patency and functional patency, likely to be explained by high primary failure rates. Hemodialysis patients with diabetes can be expected to have reduced primary functional patency rates, but if treated adequately, then arteriovenous fistula functionality can be maintained as long as in patients without diabetes.

Disparities in fistula maturation persist despite preoperative vascular mapping

BACKGROUND AND OBJECTIVES

Failure to mature (primary failure) of new fistulas remains a major obstacle to increasing the proportion of dialysis patients with fistulas. This failure rate is higher in women than in men, higher in older than in younger patients, and higher in forearm than in upper arm fistulas. These disparities in the frequency of failure to mature may be due in part to marginal vessels in the high-risk groups and should be reduced by routine preoperative vascular mapping.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A prospective, computerized database was queried retrospectively to evaluate the frequency of primary fistula failure in 205 hemodialysis patients for whom preoperative mapping was obtained. The association between clinical characteristics and risk for primary fistula failure was analyzed by univariate and multiple variable regression analysis.

RESULTS

The overall primary fistula failure rate was 40% (82 of 205 patients). On multiple variable logistic regression, three clinical factors were associated with an increased risk for failure to mature among patients who underwent preoperative vascular mapping: Female gender, age > or =65 yr, and forearm location. The primary fistula failure rate varied from 22% in younger men with an upper arm fistula to 78% in older women with a forearm fistula. Dynamic preoperative vascular measurements (change in peak systolic velocity and resistive index after tight fist clenching) did not differ between patients with mature and immature forearm fistulas.

CONCLUSION

Disparities in fistula maturation persist despite the use of routine preoperative vascular mapping.

Gender differences in vascular access in hemodialysis patients in the United States: developing strategies for improving access outcome

BACKGROUND

Patients undergoing chronic hemodialysis (HD) require placement of permanent vascular access with the creation of an arteriovenous fistula (AVF), an arteriovenous prosthetic graft (AVG), or a tunneled central venous catheter. AVFs provide greater long-term patency, fewer complications, and lower infection rates than do either AVGs or catheters. Despite these advantages, women continue to be underrepresented among AVF patients, possibly because of concerns about smaller vascular diameters and higher rates of early primary fistula failure in female HD patients. The numerous clinical benefits of AVF suggest that a greater effort should be made to promote AVF placement in women.

OBJECTIVE

This review analyzes risk factors for AVF failure in women and describes clinical strategies to improve AVF utilization and success for female HD patients.

METHODS

English-language publications were identified through a MEDLINE database search from January 1997 to March 2007, using the search terms arteriovenous fistula, vascular access, hemodialysis, female, and gender. Reference lists of identified articles were also reviewed.

RESULTS

There are significant benefits to using AVFs instead of AVGs or catheters in HD patients: greater long-term fistula patency, superior flow rates, and fewer complications. Vascular anatomical differences between the sexes contribute to the underutilization of AVF in women. AVF placement rates can be improved if patients and staff are adequately educated and provided with the tools to facilitate AVF placement. Noninvasive preoperative screening is important to identify superior access sites in women. Intraoperative monitoring of blood flow is a reliable predictor of early radiocephalic AVF patency. Routine postoperative vascular monitoring may improve overall success with AVF, and exercise may improve vascular diameter and may be even more beneficial for women, who may have smaller preoperative veins.

CONCLUSIONS

Concerns about smaller vascular diameters and reports of higher failure rates in women may prevent nephrologists and surgeons from considering AVF for female HD patients. The numerous advantages associated with AVF suggest that a greater effort should be made to increase its utilization in women. With appropriate motivation, care, and diligence by treating clinicians, the success of AVFs in women can approach the good results typically expected in men.

Clinically immature arteriovenous hemodialysis fistulas: effect of US on salvage

PURPOSE

To retrospectively determine whether postoperative ultrasonography (US) of clinically immature dialysis fistulas can be used to identify potential anatomic origins of immaturity and whether correction of immature fistulas promotes fistula maturation.

MATERIALS AND METHODS

Institutional review board approval was obtained for this retrospective study, with waiver of informed consent. Postoperative US was performed in 95 consecutive subjects (52 men, 43 women; mean age, 58 years) with clinically immature fistulas. Fistulas were deemed sonographically mature if they had a diameter of at least 4 mm, an access flow of at least 500 mL/min, and a depth of no more than 5 mm from the skin surface. Fistulas were deemed clinically mature if they could be used for dialysis for at least 1 month. The proportion of subjects in different US subgroups with fistulas that matured during follow-up was compared with chi2 analysis.

RESULTS

Sixty-seven clinically immature fistulas were deemed sonographically immature. One or more remediable anatomic problems were detected with US in 60 subjects with sonographically immature fistulas; these problems included focal stenosis in 23, accessory veins in 34, and excessively deep veins in 19. Multiple abnormalities were present in 13 subjects. Of 58 subjects with sonographically immature fistulas and known clinical outcomes, 32 underwent an intervention. In those subjects who did not undergo a salvage procedure, only eight fistulas were usable for dialysis. Among those who underwent a salvage procedure, 25 fistulas were subsequently usable for dialysis (P < .001).

CONCLUSION

Clinically immature fistulas frequently have one or more potentially remediable problems seen at postoperative US. Problem-specific salvage procedures increase the proportion of fistulas that are usable for dialysis.

Comorbidities do not influence primary fistula success in incident hemodialysis patients: a prospective study

BACKGROUND AND OBJECTIVES

Concern about primary fistula failure may contribute to the underuse of arteriovenous fistula. The objective of this study was to investigate the baseline clinical parameters associated with primary fistula success.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Consecutive incident patients who commenced dialysis during a 28-mo period in a regional renal program were studied. Data on patient-related variables and on surgical approach (e.g., whether the surgeons routinely assess vessel size during the operation) were collected. Primary fistula success was defined as an arteriovenous fistula that was able to afford successful dialysis for 3 h with blood pump speed of > or =300 ml/min for three consecutive sessions.

RESULTS

A total of 205 (69%) patients had an AVF attempted as their first vascular access. The overall primary success rate was 64% and was similar for radiocephalic and brachiocephalic fistula. Logistic regression was done separately for patients with the two types of fistula because of the presence of statistical interaction. For radiocephalic fistula, male gender was the only parameter associated with primary fistula success (odds ratio 3.57; P = 0.01). The presence of comorbidity was not significantly associated with primary fistula failure.

CONCLUSIONS

Despite significant patient comorbidity, there was a high primary fistula success rate among this incident hemodialysis cohort. Given that vessel size may be the ultimate determinant of fistula success, if surgeons assess vessel size perioperatively, then the presence of significant comorbidity might not preclude arteriovenous fistula from being attempted as the initial access.

Trends in hemodialysis vascular access from the Australia and New Zealand Dialysis and Transplant Registry (ANZDATA) 2000 to 2005

BACKGROUND

Australia historically has been recognized for its high fistula use.

STUDY DESIGN

Observational study using registry data.

SETTING & PARTICIPANTS

Adult patients registered in the Australia and New Zealand Dialysis and Transplant Association Registry on hemodialysis in Australia.

PREDICTOR

Cohort year.

OUTCOMES & MEASUREMENT

Hemodialysis access trends were examined from 2000 to 2005 for incident patients (within 60 days of hemodialysis therapy start), patients on hemodialysis therapy for 6 to 8 months, and prevalent hemodialysis patients. Multivariate analyses were performed to examine the relationship between access type and cohort year for each group, with adjustment for age, sex, race, body mass index, late referral, smoking status, cause of end-stage renal disease, comorbidities, and dialysis vintage.

RESULTS

During 2000 to 2005, catheter use increased from 39% to 53% in incident patients, 10% to 22% in the 6- to 8-month groups, and 6% to 13% in prevalent patients. Fistula use decreased from 56% to 43% in incident patients and 78% to 67% in the 6- to 8-month group and remained at 73% to 75% in prevalent patients. Graft use decreased in all groups. Adjustment for factors associated with access type did not significantly change these results.

LIMITATIONS

The registry collects only the access in use at the end of the survey period; thus, it was not possible to determine whether another access had failed or was present, but not in use. The small number of incident numbers prevented separate analysis of arteriovenous fistulas and arteriovenous grafts.

CONCLUSION

Incident use of fistulas and grafts decreased, with an unexpected increase in both incident and prevalent catheters between 2000 and 2005. Adjustment for factors associated with access type did not significantly alter the trends. Changes in unidentified practice patterns, attitudes, or preferences are contributing to these trends. Ongoing evaluation of data and investigation into processes of care are required to increase functioning fistulas, together with reevaluation of the role of grafts in patients without a fistula.

Transposed Arteriovenous Fistulae: Do the Results Justify the Effort?

Transposed arteriovenous fistulae have been utilized in clinical scenarios where simple arteriovenous fistulae have failed or their construction was not possible for anatomical reasons. Despite variability in published reports, transposed arteriovenous fistulae have acceptable patency rates and outperform prosthetic arteriovenous grafts in patency, frequency of intervention to maintain patency, and complication rates.

Obesity and Hemodialysis Vascular Access Failure

A variety of factors have been proposed to explain arteriovenous fistula primary failures in patients undergoing hemodialysis, including obesity, diabetes mellitus, female sex, and the absence of preoperative vein mapping. In this report, we describe 2 women for whom premature upper-extremity arteriovenous fistula failures occurred in the setting of venographic evidence of soft-tissue compression of the venous outflow with the patient's arm in the adducted position. In each instance, preoperative noninvasive duplex vein mapping showed veins of adequate diameter (0.28 to 0.54 cm), and further evaluation showed no evidence of a hypercoagulable state. Upper-extremity venography was used to assess central venous patency and fully assess the venous vasculature. Unlike the widely patent venous systems seen in the abducted position, venography performed with the upper extremities in adduction showed marked narrowing of the brachial and/or axillary veins. The hemodynamic effects of this narrowing were readily apparent in patient 2 with the appearance of collateral filling of the cephalic vein in the adducted position. Patient 1 had a body mass index of 39 kg/m(2), and patient 2 had a body mass index of 34 kg/m(2). Each patient had excess axillary soft tissue that appeared to compress the venous outflow in adduction. To our knowledge, this is the first report to radiographically document soft-tissue compression of the venous outflow of the upper extremity in the adducted position, suggesting a mechanism whereby obesity, or at least excess axillary fat, can lead to premature hemodialysis vascular access failures.