Clinical epidemiology of arteriovenous fistula in 2007

The native arteriovenous fistula (AVF) is considered the best access for hemodialysis due to its longer survival and lower complication rates as compared with other forms of vascular access. However, broad practice variation exists in the use of AVF among different countries and even within the same country among different regions and centers. Several barriers to AVF placement have been identified in the last decade that might explain its suboptimal use among both prevalent and incident patients. The present review summarizes and discusses recent findings from epidemiological studies on practice patterns and risk factors for AVF failure. Special emphasis is devoted to drawbacks and payoffs consequent upon the choice of the AVF as access for dialysis. In fact the AVF requires major investments in the short run but far less assistance and rework thereafter. Primary AVF failure, due to early failure or lack of maturation, is currently considered a key area of investigation to improve vascular access outcomes. The main challenge for the nephrologist today is to minimize the risk of primary failure while attempting to provide most patients with a native AVF. Improving vascular access outcomes is clearly a complex and difficult task. Recent experience from the United States suggests that multidisciplinary management is the most appropriate approach to deal with all the multifaceted aspects of end-stage renal disease care and to increase the likelihood of success.     

超声在动静脉内瘘并发症中的应用进展

动静脉内瘘(AVF)是终末期肾病患者最常用的透析通路,但在建立及透析过程中易出现各种并发症,常见者包括内瘘成熟障碍、内瘘狭窄及血栓形成等。早期发现AVF并发症并适当干预、保持通路畅通,可改善终末期肾病患者预后。超声检查可评估及辅助AVF成熟、早期发现AVF常见并发症并辅助介入治疗等。本文就超声在AVF并发症中的应用进展进行综述。     

A case report of spinal dural AV fistula which showed drastic recovery

Spinal dural AVF is the most common type of spinal AVMs. It affects especially old male with slowly progressive paraparesis in most cases. We have experienced a rare case of a middle aged male with spinal dural AVF who showed rapid deterioration in its course. The patient was treated with surgical interruption of AVF after transarterial embolization with NBCA. The patient improved well after the treatment, and intramedullary lesion on MRI disappeared after 4 years. The authors would like to stress the importance of early diagnosis and proper treatment for spinal dural AVFs.     

The Clinical Utility of Doppler Ultrasound Prior to Arteriovenous Fistula Creation

Arteriovenous fistula (AVF) is the preferred access for long-term hemodialysis, with superior long-term patency rates; however, early failure rates are significant. Recent evidence has brought into question the preferred site of AVF creation in many patient groups. A preoperative test that could reliably predict the outcome of a proposed AVF would be of great benefit. Doppler ultrasound has been the most extensively studied and widely used test to guide access creation. Accurate and validated measurements of internal vessel diameter, both arterial and venous, and blood flow in the upper extremity are obtainable by Doppler ultrasound. Studies evaluating the utility of Doppler ultrasound prior to AVF creation suggest that vessel size and blood flow are predictive of AVF outcome. An AVF created using a cephalic vein and/or radial artery smaller than 1.5–2.0 mm is likely to fail; such preoperative data may indicate that an upper arm AVF should be the primary access attempted. Further prospective studies are needed to evaluate the utility of Doppler ultrasound.     

Reducing central venous catheters in chronic hemodialysis—a commitment to arteriovenous fistula creation in children

Background

An internal permanent vascular access [arteriovenous fistula (AVF) or arteriovenous graft (AVG)] is preferred over central venous catheters (CVC) for chronic hemodialysis. However, CVC remain the most commonly used access in children. The objective of this study was to evaluate our experience with AVF.

Methods

We conducted a retrospective chart review of children aged 1–18 years on chronic hemodialysis from 2001 to 2012. Patients were divided into three time periods: 2001–2005, 2006–2009 and 2010–2012. A systematic approach to AVF placement was introduced in our department in 2006 which resulted in a greater number of AVF being placed and used, but the access failure rate was still higher than desired. In 2010, a more experienced vascular surgeon was contacted to perform AVF surgery in our most difficult AVF candidates.

Results

Sixty-five AVF were created in 55 patients (67.3 % male). The median age of the patients was 14 (3–18) years. Forty-one (63.1 %) AVF were used successfully, and this number increased from 52.6 to 57.6 to 92.3 % over the three time periods, respectively. Over time, AVF use rates increased and CVC use decreased. By 2012 only 7.7 % of our patients were using a CVC. The primary patency rate was 42.9 % at 1 year; secondary patency rates were 100 and 93.8 % at 1 and 2 years, respectively. Infection and hospitalization rates were higher for CVC than for AVF [0.8 vs. 0.1 infections per access-year (p?p?Conclusions With a dedicated approach and vascular access team it is possible to decrease CVC and increase AVF use in children on hemodialysis. In our study, increased AVF use resulted in decreased access-related infection and hospitalization rates.     

Rendu-Osler-Weber disease with a giant intracerebral varix secondary to a high-flow pial AVF: case report

BACKGROUND: Intracranial varices are rare and most are associated with vein of Galen arteriovenous malformations (AVM) or fistulas (AVF). DESCRIPTION: A 43-year-old left-handed man presented with right hemihypesthesia and spastic gait. Neuroradiological examination revealed a spinal AVF and a giant intracerebral varix associated with a high-flow pial AVF. He had recurrent episodes of nasal bleeding, which were also confirmed in his mother's medical history, and telangiectases in the tip of his tongue and fingers. He was diagnosed with Rendu-Osler-Weber disease. After resection of the spinal AVF that produced his symptoms, we surgically exposed and obliterated the giant varix and AVF under intra- and postoperative hypotension and mild barbiturate therapy. The arteriovenous shunt was completely obliterated without hyperperfusion of the surrounding brain. CONCLUSION: This is an extremely rare case of Rendu-Osler-Weber disease with a giant intracerebral varix secondary to a high-flow pial AVF that did not involve the vein of Galen.     

The relationship between arteriovenous fistula success and inflammation

Abstract

Background: Arteriovenous fistula (AVF) is the most important vascular access method for hemodialysis (HD). In this study, the relationship between AVF success and inflammation in patients who had HD due to end-stage renal failure (ESRF) was investigated. Material and method: In the study, a total of 658 patients, who started HD for ESRF, were evaluated retrospectively. A total of 386 patients were included in this study. The demographic data and C-reactive protein, albumin and fibrinogen levels were investigated in patients with recognized success AVF. Results: In total 311 patients with successful AVF and 75 unsuccessful AVFs were found. In unsuccessful AVF group the average low albumin level, high C-reactive protein and fibrinogen levels were found to be statistically meaningful when compared with successful AVF group (p?<?0.001, p?<?0.001, p?<?0.001). Conclusion: As a result, we think that the evaluation of inflammation before creating AVF in HD patients is very important for increasing the success of AVF.     

肝脏创伤性假性动脉瘤和动静脉瘘的诊治

目的 探讨肝脏创伤性假性动脉瘤(post-traumatic intrahepatic pseudoaneurysm，HPA)及动静瘘瘦(arteriovenous fistula,AVF)的临床特点及诊疗手段。方法 肝创伤性HPA／AVF病人13例，对其临床资料进行回顾性总结。结果 其主要病因为严重肝破裂伤和深部肝穿刺伤(10例)，病变部位肝右叶(8例)＞左叶(3例)＞肝门部(2例)，症状以迟发性出血伴腹痛为主(11例)，诊断率贴A＞CT＞B超。治疗包括肝动脉栓塞治疗(7例)，肝叶切除(3例)，瘤体切除、肝动脉结扎(2例)，1例未做特殊治疗。结论 创伤性HPA／AVF是肝外伤后迟发出血的重要原因，肝动脉造影及栓塞术是该类疾病的主要诊疗手段。     

Acute arterio-venous fistula occlusion decreases sympathetic activity and improves baroreflex control in kidney transplanted patients.

BACKGROUND: The acute bradycardia induced by the occlusion of an arteriovenous fistula (AVF), known as the Nicoladoni-Branham sign, is considerably larger than that which occurs during carotid sinus massage. This suggests increased arterial baroreflex sensitivity during acute AVF occlusion. Moreover, the influence of acute AVF occlusion on muscle sympathetic nerve traffic (MSNA, by microneurography) is unknown. We therefore assessed the effects of acute AVF occlusion on baroreflex sensitivity and on MSNA in patients with stable functional kidney grafts and patent AVF. METHODS: We measured blood pressure (BP), MSNA (n = 11), heart rate (HR), cardiac output (CO) and arterial baroreflex sensitivity (n = 18) at baseline and during acute, 30-s pneumatic AVF occlusions in 23 renal transplanted recipients. RESULTS: During the first 5 s of the AVF occlusion, mean BP increased from 98+/-4 to 112+/-4 mmHg (P<0.0001) while MSNA decreased to 28+/-5% of baseline values (P<0.0001) and HR decreased from 71+/-3 to 61+/-3 b.p.m. (P<0.0001). The largest increases in BP were accompanied by the most marked decreases in MSNA (r = -0.79, P = 0.003) and HR (r = -0.49; P = 0.01) during the first 5 s of the AVF occlusion. During AVF occlusion baseline CO of 6.9+/-0.3 decreased to 5.6+/-0.3 l/min (P<0.0001) while baroreflex sensitivity increased from 10+/-1 to 17+/-2 ms/mm Hg (P<0.001). CONCLUSIONS: Arterial baroreceptor activation and increased arterial baroreflex sensitivity decrease heart rate during AVF occlusion. In addition, our study is the first to demonstrate that arterial baroreflex activation decreases sympathetic nerve traffic during the Nicoladoni-Branham sign.     

Multi-center investigation of intial hemodialysis vascular access in end-stage renal disease patients

Objective To investigate vascular access modalities at initiation of hemodialysis for end stage renal disease (ESRD) patients in hospitals of different levels, and to analyze the reasons contributing to the absence of arteriovenous fistula (AVF) during initial hemodialysis. Methods A pre-designed questionnaire was used to collect the information of patients that entered hemodialysis within five years, including basic information and their first vascular access types, and analyze the factors that influence patients' AVF use. Results (1) According to the 203 questionnaires returned from 5 hospitals, central venous catheter (CVC) was chosen by 122 (60.1%) patients, direct arteriovenous puncture by 44 (21.7%) patients, AVF by only 35 (17.2%) patients, and long-term cuffed catheter by 2 (1.0%) patients. For patients in different hospitals, 61.7% of patients in Jiamusi Hospital used direct arteriovenous puncture, while CVC were used most in the other four hospitals. The leading reason contributing to the absence of AVF was patient's refusal [75 cases (44.6%)], among which patients regarding AVF psychologically unacceptable accounted for the most [44 cases (26.2%)]. Following that were 45 cases (26.8%), in which patients were uninformed of AVF and 38 cases (22.6%) caused by time limitation. (3) Logistic regression showed well-educated, female, and urban residential patients were more likely to choose AVF at initiation of hemodialysis. Conclusion The percentage of AVF utility at the start of hemodialysis remains low, with situation varying in different hospitals and regions. Multiple factors are associated with vascular access modalities, among which the influence of doctors cannot be ignored. More efforts should be spared on patient education to improve the dialysis quality of ESRD patients in China.     

头发移植术后并发动静脉瘘的治疗

头发移植是以男性秃发患者为主的最常见的美容手术 ,其中打孔自体皮片移植是最简单最有效的方法 ,并发症少见报道。文献回顾目前国外有 9例头发移植术后发生了动静脉瘘 (ArteriovenousFistula简称AVF)。其症状为在术后数周至数月在头皮任何区域出现的一个或数个异常隆起的肿块 ,有搏动、杂音等症状 ,甚至会引起出血、头皮坏死。有时有局部疼痛或头痛症状。文献中多见为发生于受区的AVF。本文报道了我科近十年来 2 0 0 0多次10 0 0多名患者头发移植术后发生的 5例AVF ,其中 4例发生于颞浅动静脉区 ,1例发生于枕动静脉区 ,提示AVF在较粗动静脉同时受损时容易发生。发生年龄集中于 3 0岁左右 ,提示青年好发。讨论了AVF的形成 ,治疗方式 ,尤其是对AVF的环扎治疗 ,它能快速止血 ,对应急处理特别有效。本文还讨论了如何尽可能减少AVF的发生。     

Effects of smoking and blood eosinophil count on the development of arteriovenous fistulae thrombosis in hemodialysis patients

Arteriovenous fistulae (AVF) failure is the most common cause of morbidity and hospitalization in hemodialysis (HD) patients. The purpose of this study was to determine the effects of smoking and blood eosinophil count on the development of AVF thrombosis in HD patients. This cross-sectional study included 141 patients (M/F 80/61; age 43.4 +/- 11.6 years, HD duration 7.7 +/- 4.4 years). The following were analyzed as possible risk factors for AVF failure for all patients: demographic features, dialysis time, smoking, medications, body mass index, comorbid diseases, and various laboratory parameters (whole blood count and serum levels of albumin, calcium, phosphorus, uric acid, C-reactive protein, ferritin, and parathyroid hormone). AVF thrombosis was detected in 60 patients; in contrast, 81 patients had no thrombosis. Distributions of age, gender, and HD duration were similar between both groups. Univariate analysis showed that snuffbox AVF location (P < .0001), higher blood eosinophil count (P < .0001), smoking (P < .01), and higher hematocrit level (P < .05) were all associated with AVF thrombosis. According to multivariate analysis by logistic regression models, eosinophil count (RR = 1.005, P < .05) and snuffbox location (RR = 5.970, P < .05) were predictors of AVF thrombosis. When AVF location was excluded from the analysis, smoking (RR = 4.140, P < .01) and high blood eosinophil count (RR = 1.006, P < .005) were independent risk factors for thrombosis. Our study indicates that smoking and high blood eosinophil count may contribute to the development of AVF thrombosis.     

A prospective controlled trial on effect of percutaneous transluminal angioplasty on functioning arteriovenous fistulae survival

Balloon angioplasty (PTA) is an established treatment modality for stenosis in dysfunctional arteriovenous fistulae (AVF), although most studies showing efficacy have been retrospective, uncontrolled, and nonrandomized. In addition, it is unknown whether correction of stenosis not associated with significant hemodynamic, functional, and clinical abnormality may improve survival in AVF. This study was a prospective controlled open trial to evaluate whether prophylactic PTA of stenosis not associated with access dysfunction improves survival in native, virgin, radiocephalic forearm AVF. Sixty-two stenotic, functioning AVF, i.e., able to provide adequate dialysis, were enrolled in the study: 30 were allocated to control and 32 to PTA. End points of the study were either AVF thrombosis or surgical revision due to reduction in delivered dialysis dose. Kaplan-Meier analysis showed that PTA improved AVF functional failure-free survival rates (P = 0.012) with a fourfold increase in median survival and a 2.87-fold decrease in risk of failure. Cox proportional hazard model identified PTA as the only variable associated with outcome (P = 0.012). PTA induced an increase in access blood flow rate (Qa) by 323 (236 to 445) ml/min (P < 0.001), suggesting that improved AVF survival is the result of increased Qa. PTA was also associated with a significant decrease in access-related morbidity by approximately halving the risk of hospitalization, central venous catheterization, and thrombectomy (P < 0.05). This study shows that prophylactic PTA of stenosis in functioning forearm AVF improves access survival and decreases access-related morbidity, supporting the usefulness of preventive correction of stenosis before the development of access dysfunction. It also strongly supports surveillance program for early detection of stenosis.     

Technique for a single-time correction of arteriovenous fistula aneurysm in conjuction with creation of a new venous drainage pathway

Aneurysm and stenosis are among the most frequent complications of an arteriovenous fistula (AVF) for hemodialysis. The occurrence of the two kinds of problem may be found in one and the same patient, affecting the use of the AVF and even rendering its use impossible. We report the technique used for correction of a patient's aneurysmal dilations of radio-cephalic AVF and stenosis after the aneurysmal segment, with an increase in post-punction bleeding during the hemodialysis sessions. This was treated with resection and aneurysmorrhaphy associated with the preparation of a new anastomosis with the brachial vein.     

Limb complaints after autogenous arteriovenous fistula creation in chronic hemodialysis patients

Placement of autogenous arteriovenous fistula (AVF) is one of the basic needs in hemodialysis patients. Although many studies have investigated the complications of AVF placement, the complaints expressed by patients have not been studied in a long-term study. The purpose of this study was to evaluate the incidence of complaints after placement of autogenous AVF in patients undergoing chronic hemodialysis. This cohort study was conducted on patients with end-stage renal disease undergoing AVF placement who were referred to Imam Reza hospital in Mashhad, Iran, from January 2015 to June 2016. The AVFs were placed in all patients and incidence rates of expressed complaints, including pain, paresthesia, and edema, were assessed up to three periods 1 month after surgery and three periods 2 months after starting use of the AVF. Data were analyzed using SPSS software, version 19. The relationship of AVF types with each of the outcomes was analyzed via χ² test. Three hundred and eighty-eight patients (222 males and 166 females; mean age 54.3 ± 16.0 years) were studied. AVF was established in the cubital site of 230 patients, in snuff box of 103 patients, and distal forearm of 55 patients. Total incidence rate of pain within six follow-up periods and incidence rates of paresthesia and edema were determined as 18.1%, 2.6%, and 5.4%, respectively. A statistically significant relationship was observed between types of AVF and pain and paresthesia (P < .05). According to results from this study, pain and then edema were the most common complaints, followed by AVF placement in the patients. Paresthesia had lower incidence rates compared to other complaints.     

Predictors of early vascular-access failure in patients on hemodialysis

Vascular access management is key and critical in the successful management of hemodialysis patients, and an arteriovenous fistula (AVF) is considered the access of choice. This study was conducted between January 2007 and October 2009 at the Military Hospital in Rabat. Data on 115 patients who underwent 138 AVFs were retrospectively studied. Wrist AVF was the most common site of use. The primary course was uncomplicated in 63% of the patients, while primary failure occurred in 23.9% of the patients. Presence of diabetes was the most important risk factor for primary failure.     

Best threshold for diagnosis of stenosis or thrombosis within six months of access flow measurement in arteriovenous fistulae

Canadian clinical practice guidelines recommend performing angiography when access blood flow (Qa) is <500 ml/min in native vessel arteriovenous fistulae (AVF), but data on the value of Qa that best predicts stenosis are sparse. Because correction of stenosis in AVF improves patency rates, this issue seems worthy of investigation. Receiver-operating characteristic curves were constructed to examine the relationship between different threshold values of Qa and stenosis in 340 patients with AVF. Stenosis was defined by the composite outcome of access failure or angiographic stenosis occurring within 6 mo of the first Qa measurement. The Qa value was then classified as true negative, true positive, false negative, or false positive for stenosis. An additional analysis was performed in which Qa was corrected for systolic BP before assigning it to one of the four diagnostic categories. The area under the curve for the composite definition of stenosis was 0.86. Graphically, Qa thresholds of <500 and <600 ml/min had similar efficacy for detecting stenosis or access failure within 6 mo, and both seemed superior to <400 ml/min. However, the frequency of the composite definition of stenosis among AVF with Qa between 500 and 600 ml/min was only 6 (25%) of 24, as compared with 58 (76%) of 76 when Qa was <500 ml/min. This suggests that most lesions that would be found using a threshold of <600 ml/min occurred in AVF with Qa <500 ml/min and that the small gain in sensitivity associated with the <600-ml/min threshold would be outweighed by the reduced specificity compared with <500 ml/min. Correcting Qa for BP did not improve diagnostic performance or change these results, which were consistent in several sensitivity analyses. Qa measurements seemed to predict stenosis or incipient access failure equally well in groups defined by diabetic status, gender, and AVF location. In conclusion, it was found that Qa <500 ml/min seems to be the most appropriate threshold for performing angiography in patients with native vessel AVF. It is recommended that clinicians arrange angiography when Qa is <500 ml/min in AVF.     

Alternative autogenous arteriovenous hemodialysis access options

An autogenous arteriovenous hemodialysis access (AVF) remains the consensus-recommended vascular access for individuals requiring hemodialysis. Surgical options, strategies, and guidelines have been established by several organizations, including the National Kidney Foundation, the Fistula First Breakthrough Initiative, and the Society for Vascular Surgery. Establishing a successful AVF in a high percentage of patients requires a thorough knowledge of the many access options and clinical practice recommendations, in addition to a careful clinical history/physical examination, pre- and postoperative ultrasound, and further vascular imaging in select patients. The more common AVF configurations may not be possible in complex patients because of limited venous outflow, arterial insufficiency, or both. However, the vascular access surgeon may still be able to construct a successful AVF in these challenging patients by utilizing one of several alternative procedures. Avoiding prosthetic arteriovenous accesses and central venous catheter-based dialysis is feasible in most patients. This article reviews some of the alternative options for establishing successful AVFs.     

Evaluation of clinical examination preceding surgical treatment of AV-fistula problems. Is angiography necessary?

Clinical and angiographic findings at preoperative assessment were compared in a prospective investigation of 34 consecutive uraemic patients with problems of vascular access. The series comprised 26 patients with malfunctioning arteriovenous fistulas (AVF) and 8 who were about to receive a new AVF. The diagnostic sensitivity and specificity of clinical examination in malfunctioning AVF were, respectively, 50 and 100% in cases with significant stenosis upstream from the cannulation site (inflow restriction). The corresponding figures in cases with significant stenosis or vein occlusion downstream from the cannulation site (outflow restriction) were 38 and 43%. Clinical disclosure of outflow restriction is considerably impeded when there is concurrent inflow restriction. The advantages and disadvantages of the most commonly used angiographic techniques are discussed.     

Arteriovenous access fistulae diminish cardiac reserve, anaerobic threshold and work capacity: A case for fistula closure in stable renal transplant recipients

Summary: A patent arteriovenous fistula (AVF) in stable renal transplant recipients may be viewed as 'insurance' against late graft failure and a return to haemodialysis. A patent AVF may, however, exert significant chronic demands on cardiac output (CO) which may in turn adversely affect the prognosis of patients already at risk of cardiac disease. Doppler echocardiography and anaerobic threshold (AT) assessment were used to measure the CO and the work capacity of nine stable renal transplant recipients > 15 months post transplantation who had patent AVF. Cardiac output fell from 6.9 ± 1.48L/min with the AVF open to 6.0 ± 0.97L/min with the AVF closed ( P < 0.002). the AT rose from 14.1 ± 5.67 with the AVF open to 16.5 ± 6.72 with the AVF closed ( P < 0.002). the work capacity to reach the AT improved from 68.7 ± 30.8 watts with the AVF open to 84.6 ± 38.0 watts with the AVF closed ( P < 0.004). This study suggests that a significant and chronic increase in left ventricular work-load accompanies a patent AVF resulting in a markedly reduced exercise efficiency. A patent AVF is ideal where graft survival is doubtful but, where long-term graft function is expected, the adverse effects of AVF patency, a chronic elevation in CO and reduced exercise capacity make a strong case for considering AVF closure. the prognostic advantage for left ventricular function may outweigh AVF preservation in stable renal transplant recipients.