Vascular access for hemodialysis: arteriovenous fistula

The long-term survival and quality of life of patients on hemodialysis (HD) is dependant on the adequacy of dialysis via an appropriately placed vascular access. The optimal vascular access is unquestionably the autologous arteriovenous fistula (AVF), with the most common method being the conventional radio-cephalic fistula at the wrist. Recent clinical practice guidelines recommend the creation of native fistula or synthetic graft before the start of chronic HD therapy to prevent the need for complication-prone dialysis catheters. This could also have a beneficial effect on the rapidity of worsening kidney failure. A multidisciplinary approach (nephrologists, surgeons, radiologists and nurses) should improve the HD outcome by promoting the use of AVF. An important additional component of this program is the Doppler ultrasound for preoperative vascular mapping. Such an approach may be realized without unsuccessful surgical explorations, with a minimal early failure rate and a high maturation, even in patients with diabetes mellitus.     

Access surgery for hemodialysis in the Cayman Islands: Preliminary results of a vascular access service

OBJECTIVE:

In the Cayman Islands, a vascular access service was created in 2005 to facilitate the creation of vascular access for hemodialysis by local surgeons. The present retrospective audit aims to establish the outcomes of this practice in the Cayman Islands.

METHODS:

Data from the operative log of the Cayman Islands Hospital was collected over a period of 36 months. The data were analyzed using SPSS version 12.0 (SPSS Inc, USA). Statistical analyses were performed using Student’s t tests and Fisher’s exact tests.

RESULTS:

A total of 19 operative procedures were performed to create vascular accesses in 12 men and seven women. Thirteen procedures (68%) created autogenous arteriovenous fistulas (AVFs) and six (32%) involved the insertion of a prosthetic arteriovenous graft (AVG). There were six incident dialysis patients, all of whom had an AVF created. The remaining 13 prevalent dialysis patients had new accesses in the form of AVFs (n=7) or AVGs (n=6).The statistical analyses were limited by sample size, but with AVFs, there were trends toward reduced incidence of secondary failure (four of 13 versus four of six), thrombosis (four of 13 versus two of six), infectious morbidity (zero versus two of six) and less demand for interventions to maintain patency (one of 13 versus two of six) with AVFs. There were also trends toward superior primary (461 days versus 227 days) and secondary (803 days versus 205 days) patency rates for AVFs.

CONCLUSIONS:

In this setting, the rate of AVF creation exceeds the goals set by the National Kidney Foundation Kidney Disease Outcomes Quality Initiative and the Fistula First Breakthrough Initiative. To ensure continued delivery of modern quality care, further audits of the local practice will be required at regular intervals.     

Complications of Native Arteriovenous Fistula: The Role of Color Doppler Ultrasonography

Color Doppler ultrasonography (CDUS) is a readily available, inexpensive and noninvasive method, which has improved the survival of native arteriovenous fistula (AVF) by increasing the early diagnosis of complications. Although angiography has been currently considered as the gold standard for imaging of vascular access abnormalities, CDUS may be superior in some aspects, since it provides information both on the morphology and on the function of vascular access and it is the only tool directly available to the nephrologist. In addition, CDUS offers the advantage of a non‐invasive bedside procedure with lower costs and with no need for radiocontrast.     

Ultrasonographic Assessment of Polytetrafluoroethylene Upper Extremity Arteriovenous Hemodialysis Access: A Retrospective Analysis of 31 Cases

Polytetrafluoroethylene (PTFE) vascular grafts are used for hemodialysis vascular access. Because their longevity is less than that of autologous fistulae, close surveillance is necessary to reduce the incidence of complications. The purpose of this study was to evaluate the usefulness of Doppler sonography for the surveillance of PTFE graft hemodialysis access. Thirty‐one patients with renal failure who had dialysis access created with a PTFE graft were included in this study. The patient records along with ultrasonography were retrospectively reviewed. Two‐dimensional ultrasonography clearly revealed the U‐shape of the subcutaneous PTFE graft, and autologous artery and superficial vein connecting with the graft. There was no ultrasound echo inside the graft, but the wall was a continuous line‐like hyperechoic structure. Blood flow in the graft and hemodynamic parameters could be determined with color Doppler ultrasonography. Ultrasound examination diagnosed graft thromboses in six patients, pseudoaneurysm in two, seroma in one, and subcutaneous edema in three patients. Ultrasonography is useful for the monitoring and diagnosis of complications of PTFE dialysis access grafts.     

动静脉内瘘对血液透析患者心脏功能的影响

目的探讨动静脉内瘘对血液透析患者心脏功能的影响。方法对中国医科大学附属第二医院肾内科2004—2005年收治的55例尿毒症血液透析患者于动静脉内瘘术(AVF)前后进行心脏彩色超声心动图检测,对比分析左心房内径(LAD)、左心室内径(LVD)、左室舒张末容积(LVEDV)、左心室每搏输出量(SV)、左心室射血分数(EF)及右心室内径(RVD)指标的变化。结果AVF术后LAD、RVD、LVD、LV-EDV均有不同程度的增大,而EF水平下降,P<0·05有统计学意义;SV有所增加,P>0·05无统计学意义。结论AVF可以造成血液透析患者左心房、心室腔的扩大,左心室的收缩功能下降。     

Vascular Access in Patients Treated With Chronic Hemodialysis for 30 Years or More

The aim of our study was to evaluate vascular access in patients treated with chronic hemodialysis for 30 years or more. Patients who had started dialysis in 1978 or earlier were identified from the Slovenian Renal Replacement Therapy Registry. The data on vascular access on April 2008 are presented. Sixteen patients were still alive, seven men and nine women aged 62 ± 12 years (46–84), and they had been treated for 32 ± 1.7 years (30–35), mainly with chronic HD. They had started HD at the age of 30 ± 12 years (13–50), and none had diabetes. The vascular access in nine was a native arteriovenous (AV) fistula, on the forearm in eight patients, and a brachiobasilic fistula in one patient. Four patients had their primary AV fistulas still in use (maximum 35 years). In the remaining five patients, multiple salvage procedures had been performed or new AV fistulas created. The vascular access in four patients was the polytetrafluoroethylene (PTFE) graft, functioning for 1–8 years. In three patients, a non‐cuffed, single‐lumen hemodialysis catheter (a precurved jugular in two patients and a subclavian in one) locked with 30% citrate, with mupirocin at the exit site, was used for 5–12 years. The catheters were exchanged approximately once every two years over a guide‐wire because of mechanical damage. None of these three patients had had catheter‐related sepsis or exit‐site infection. Before catheters, these patients had had multiple AV fistulas and PTFE grafts. Although native AV fistula is the predominant type of vascular access, a greater than 30‐year survival on hemodialysis is possible with the combined use of AV fistula, PTFE graft, and a non‐cuffed hemodialysis catheter locked with citrate.     

Microsurgery in children for creation of arteriovenous fistulas in renal and non-renal diseases

Microsurgery for angioaccess in children includes the use of a surgical microscope, microsurgical instruments, prophylactic tourniquet-induced hemostasis and no-touch surgery. In the recent publications concerning angioaccess in children, the percentages of grafts versus arteriovenous fistulas (AVF) varied from 54 to 76% without microsurgery, and from 0 to 14% with microsurgery. Similarly, the percentages of AVF which failed to mature varied from 30 to 33% without microsurgery, and from 5 to 10% with microsurgery. In a personal series of 380 children receiving hemodialysis, 434 microsurgical angioaccesses were created, 78% being distal autologous AVF. Eighty-five percent of the distal radial-cephalic AVF were patent after 2 years and 60% after 4 years. These results of microsurgically created AVF are probably responsible, at least in part, for the high percentage of end-stage renal disease (ESRD) children treated by hemodialysis on 1 February 2003 in Paris using an autologous fistula (70% of 33 children), while only 24% were hemodialyzed via a central venous catheter and 6% were on peritoneal dialysis. This compares favorably with the annual publication of the North American Pediatric Renal Transplant Cooperative Study in 1996 reporting that two-thirds of the dialysis population were maintained on peritoneal dialysis and that the majority of hemodialysis accesses were external percutaneous catheters. Microsurgical AVF are also created successfully in non-ESRD children requiring frequent blood access for various chronic diseases. It has been possible to create a distal AVF in 68% of cases and the long-term patency rate was just below 60% after 10 years. Microsurgery is mandatory for creation of arteriovenous fistulas, the best form of angioaccess for children treated by hemodialysis or requiring repeated access to blood in various non-renal diseases.     

Vascular access in children on chronic hemodialysis: a Slovenian experience

The aim of our study was to report our experience with arteriovenous fistulas (AVFs) and non-cuffed central venous catheters (CVCs) in children and adolescents with end-stage renal disease (ESRD) on hemodialysis (HD). The children with ESRD (18 years or younger) who were hemodialyzed at the Center of Dialysis and Transplantation, Children's Hospital, Ljubljana, in the period between December 1998 and December 2010 were included in our retrospective study. We recorded the data considering the CVCs and AVFs used for HD. Thirty-one children (13 females, 18 males) with ESRD received HD treatment. The mean patient age when HD was started was 13.3 ± 3.4 years. Altogether, 35 AVFs were created, and the primary failure rate was 25.7% (9/35). The time to maturation was 4.0 ± 2.5 months. The mean patency of the AVF was 42.5 ± 51.9 months. Seventy-seven CVCs (non-cuffed) were inserted in the observation period; 89.6% of the CVCs were inserted in the jugular vein, and citrate locking was used in the interdialysis period. The CVCs were removed after 0.1-17.4 months (3.6 ± 3.7 months). The incidence of bacteremia was 0.9 episodes per 1000 catheter days. The preferred vascular accesses for pediatric hemodialysis are native AVFs; however, a single lumen, non-cuffed, citrate-locked CVC placed in a jugular vein can be acceptable as a long-term vascular access when AVF cannot be constructed or used.     

改良鼻烟窝动静脉内瘘对血液透析患者心功能的影响

目的探讨改良鼻烟窝动静脉内瘘（AVF）对血液透析患者心功能的影响。方法选取我院采用动静脉内瘘进行维持性血液透析患者60例，根据手术部位不同将患者分为两组：A组30例，行前臂桡动脉与头静脉端侧吻合术；B组30例，行改良鼻烟窝处桡动脉末端与头静脉端侧吻合术。彩色多普勒超声显像观察患者AVF术前、术后1个月、术后半年的心输出量（CO）、心脏指数（CI）、射血分数（EF）和短轴缩短率（FS），同时测定不同时期内瘘吻合口直径（AVFD）、内瘘血流量（AVFB）值。结果术后1个月及术后半年心输出量、心脏指数较术前明显增高（P〈0．01），射血分数、短轴缩短率变化不明显；AVFB、AVFD与心输出量差值（△CO）、心脏指数差值（△CI）呈直线正相关（r=0．499，P〈0．01）。A组AVFB、△CO、△CI明显大于B组（P〈0．05）。结论AVF对血液透析患者的心功能有一定影响。改良鼻烟窝AVF与前臂AVF比较，其血流量相对较小，对患者心功能的影响较小。     

Outcomes of salvage procedures for occluded autogenous radiocephalic arteriovenous fistula

The outcomes of surgical and endovascular treatments for thrombosed access fistulas are variable and provide no definitive indications for treatment choice. We purposed to review our experience in treating thrombosed radiocephalic arteriovenous fistulas (AVFs) and to evaluate the outcome of procedures, including proximal neo‐anastomosis (NEO), replacement of the stenosed segment with a polytetrafluoroethylene graft (GI), patch angioplasty (PA), and endovascular procedures (such as percutaneous transluminal angioplasty [PTA]). A total of 117 occluded radiocephalic AVFs were treated by surgery or an endovascular procedure from January 2002 to December 2007. We evaluated the rates of initial success, re‐thrombosis, the post‐interventional five‐year patency rate, and temporary catheter requirement. Forty‐five patients (38.5%) underwent NEO, 32 patients (27.4%) GI, 10 patients (8.5%) PA, and 30 patients (25.6%) PTA. The overall initial procedural success rate was 98.3% (surgery 98.9% and PTA 96.7%), and the post‐interventional patency rates at five years were 92.2% (97.1% for NEO, 82.7% for GI, 90.0% for PA, and 96.7% for PTA). Twenty‐four patients (20.5%) required a temporary catheter during healing of the functioning segment after treatment: four patients for NEO, 18 patients for GI, two patients for PA, and no patients for PTA (P < 0.001). Both surgery and endovascular treatment gave high rates of initial success and low re‐thrombosis rates as salvage treatments for occlusion of radiocephalic AVFs, if treatments were selected according to the length, and location of the stenosis to be corrected. When stenosis of a long segment is suspected, endovascular treatment should be attempted first in order to maintain the functional segment and thereby avoid use of a temporary catheter.     

Infection Rates Following Buttonhole Cannulation in Hemodialysis Patients

Arteriovenous fistula (AVF) is the preferred access for hemodialysis (HD). Buttonhole (BH) needling has increased following the introduction of “blunt” fistula needles. Although some reported advantages for BH needling, others have reported increased infection risk. As such we reviewed our center practice, and the effect of both nasal screening and eradication and re‐education and training programs. We audited the outcomes of 881 HD patients dialyzed between November 2009 and May 2012, divided into three groups: 175 dialyzing exclusively by central venous catheter (CVC), 478 exclusively by area needling AVF (AVF) and 219 by BH. There were 31 Staphylococcus aureus bacteremias (SABs); 14 (45.2%) dialyzing with CVCs, 12 (38.7%) BH and five (16.1%) AVF. The 30 day mortality rate for SAB was 7.5% with a complication rate of 22.6%. The hazard ratio for first SAB was significantly greater for both CVC and BH access compared to AVF (5.3 (95% CI –1.9–18.6), P < 0.001 and 3.6 (1.3–96), P = 0.011, respectively). During the study SAB rates per 1000 CVC days were 0.21, compared to 0.15 for BH. After major re‐education and asepsis technique campaigns the SAB rate for BH fell to 0.06, but quickly returned to 0.17. Extending BH needling to all our dialysis centers, SAB infection rates increased to those not dissimilar to CVC access. Despite re‐education programs coupled with a strict asepsis policy and active SA eradication, followed by audit cycles, the increased infection risk with BH remained, such that we have limited BH to self‐care patients.     

Preoperative Ultrasonographic Mapping of Blood Vessels Before Arteriovenous Fistula Construction in Elderly Patients With End‐stage Renal Disease

The aim of our retrospective study was to evaluate the ultrasonographic mapping of both arm and forearm vessels before primary arteriovenous fistula (AVF) construction in elderly patients with end‐stage renal disease. There were 129 patients aged 75 ± 6 (65–93) years, 58% men, 37% diabetics, who participated in the study. The inner diameter of veins (under compression) and arteries, and the arterial peak systolic velocity (PSV) were measured. The presence of arterial calcifications was noted. The positions for possible native AVF construction (radiocephalic and brachiocephalic) were suggested and an AVF was constructed by a trained nephrologist. An adequate cephalic vein was present in 76 (59%) patients (diameter 4.9 ± 1.1 mm) in the right arm, and in 83 (64%) patients (4.7 ± 1.2 mm) in the left arm. Suitable veins in the forearm were recorded in 73 (57%) patients on the right (3.7 ± 0.7 mm) and in 76 (59%) patients on the left (3.5 ± 1.0 mm) side. The inner arterial diameter was: brachial—right 4.6 ± 0.6 mm (calcifications in 26%), left 4.6 ± 0.7 mm (calcifications in 20%); radial—right 2.3 ± 0.4 mm (calcifications in 36%), left 2.3 ± 0.5 mm (calcifications in 29%). In 32% of patients, one native AVF was possible, in 17% two, in 23% three and in 18% four, while in 10% no AVF was possible. In 84% of patients an AVF was constructed, with no significant difference in non‐diabetic vs. diabetic patients (88% vs. 80%) or females vs. males (87% vs. 83%). Native AVF can be constructed in the majority of elderly patients, often in multiple positions, with no significant differences in terms of sex or diabetic status.     

Cost-benefit comparison of hemodialysis access creation in a developing country and North American centres

OBJECTIVE:

It has been suggested that vascular access operations should only be performed in high-volume centres to ensure good outcomes. Vascular access operations have been routinely performed in the Cayman Islands since 2005. However, with an estimated population of 45,000 persons, only a small number of patients require vascular access in any given interval. A cost-benefit analysis of this practice was performed.

METHODS:

All patients who had vascular access operations over four years were retrospectively identified. Two groups were defined – the local group, who had operations performed by surgeons in the Cayman Islands, and the offshore group, who were transferred off the island and had operations overseas. Cumulative cost, morbidity, patency and failure rates were compared. Significance was considered present with a two-tailed P≤0.05.

RESULTS:

There were 14 patients in the local group and 22 in the offshore group. The mean cost of access creation was 6.9 times greater in the offshore group (US$26,883.36 versus US$3,913.33; P<0.001). The likelihood of the use of arteriovenous grafts was significantly greater in the offshore group (P=0.04). When therapeutic outcomes were compared, there were no differences in primary or secondary failure, primary or secondary patency, or overall access-specific morbidity.

CONCLUSIONS:

In the present setting, vascular access creation exceeded all the goals set by the National Kidney Foundation Kidney Disease Outcomes Quality Initiative and the Fistula First Breakthrough Initiative. Compared with overseas centres, this is being achieved at a significantly lower cost, with a greater likelihood of native fistula use and similar therapeutic outcomes.     

Systematic Evaluation of Vascular Access by Color‐Doppler Ultrasound Decreased the Incidence of Emergent Vascular Access Intervention Therapy and X‐Ray Exposure Time: A Single‐Center Observational Study

Arteriovenous fistula has superior patency over other accesses, but vascular access intervention therapy (VAIVT) for stenosis or thrombosis still remain major reasons for hospital admission of dialysis patients. The aim of this study was to examine the usefulness of systematic evaluation of vascular access by color‐Doppler ultrasound (CDUS). This study was a single‐center observational design study. We planned screening CDUS to evaluate all vascular accesses once per year, and additionally, follow‐up CDUS of post‐interventional patients 1 month, 3 months and 6 months after their recent VAIVT. This systematic evaluation was started from September 2009. The observational period between September 2008 and August 2009 was defined as period A. The observational period between September 2009 and August 2010 was defined as period B. We compared the incidence of emergent VAIVT and X‐ray exposure time during the period A to B. 131 patients with AV fistula were assigned. 13 patients were excluded due to death, hospital transfer or re‐operation of their accesses. During period A, 57 VAIVTs were carried out, and 37 cases (65%) were emergent. During period B, 42 VAIVTs were carried out, and 11 cases (25%) were emergent. The incidence of emergent intervention therapy was lower during period B than period A (P < 0.001). The amount of X‐ray exposure time per patient was decreased in patients who received VAIVT during both periods (P < 0.03). Systematic evaluation of vascular access by CDUS decreased the incidence of emergent VAIVT and X‐ray exposure time.     

Upper Limb Disability in Hemodialysis Patients: Evaluation of Contributing Factors Aside From Amyloidosis

This cross‐sectional case‐control study evaluated upper limb muscle strength and shoulder mobility in hemodialysis (HD) patients with arteriovenous fistula or graft. Twenty‐five adult patients on thrice‐a‐week HD treatment for 6 months at least, were selected for the study. In all the patients and control subjects, handgrip tests and tests of range of motion in the upper extremities were evaluated by physiotherapy tests. Patients on HD showed lower muscle strength than age and sex matched subjects without severe chronic kidney disease (right: 30.1 ± 11.6 vs 40.5 ± 15.1 kg, P < 0.001; left 29.1 ± 12.9 vs 40.7 ± 11.1 kg, P < 0.01), and a reduced range of shoulder mobility. The presence of fistula or graft was associated with a greater limitation of both active (74.0 ± 18.3 vs 85.2 ± 8.8 °, P < 0.01) and passive (82.2 ± 9.9 vs 87.2 ± 6.6 °, P < 0.05) extra‐rotation than the contralateral limb, with a higher prevalence of impingement (72 vs 36%, P < 0.05). Muscle strength was related to albumin and inversely to age; whereas β₂‐microglobulin and CRP serum levels were associated with impairment of passive and active extra‐rotation of the shoulder that was free from the fistula or graft. In summary, patients on HD have a reduced range of shoulder mobility and marked reduction of muscle strength. The abnormalities are more prevalent in upper limbs with fistula or grafts. The arteriovenous fistula or graft may worsen the disability of the patient's upper limbs presumably due to the obligate position required during the HD sessions. Proper pre‐ and post‐dialysis exercise programs should be implemented to maintain mobility and strength of the upper limbs.     

Calcium channel antagonists reduce restenosis after percutaneous transluminal angioplasty of an arteriovenous fistula in hemodialysis patients

Percutaneous transluminal angioplasty (PTA) for stenosis of hemodialysis fistulas is associated with a high incidence of restenosis, and improvement of the patency rate after PTA is greatly needed. In addition, angiotensin II receptor blockers (ARB), calcium channel antagonists (CCA) and antiplatelet agents (APA) are commonly administered to most hemodialysis patients. This study retrospectively examined the effect of these medications on the incidence of restenosis after angioplasty for hemodialysis fistulae. The subjects were 92 patients--54 with anastomotic stenosis of an arteriovenous fistula (AVF) and 38 with stenosis of the draining veins of an arteriovenous graft (AVG)--who underwent angioplasty between January 2001 and December 2003. The patency period was defined as the interval from the first to the second angioplasty or surgical reconstruction. We excluded patients who received angioplasty two or more times. The effect of each drug on the patency of the AVF or AVG was assessed by the Kaplan-Meier method with the log-rank test and multiple logistic regression analysis. The group receiving CCA therapy showed a higher patency rate for both an AVF and an AVG. Although multiple logistic regression analysis also showed that a CCA reduces restenosis independently in an AVF, there was no significant correlation between a CCA and patency in an AVG. Treatment with an ARB and an APA was not associated with significantly higher patency rates for either an AVF or AVG. A CCA may reduce the incidence of restenosis after percutaneous intervention for stenosis of an AVF.