Long-term outcomes of transposed basilic vein arteriovenous fistulae

The need for reliable, long-term hemodialysis vascular access remains critical. To determine the long-term outcomes of transposed basilic vein arteriovenous fistulae (BVT) and their comparability with other vascular accesses, we determined retrospectively the primary and secondary patency rates in 58 BVT and in a total of 58 arteriovenous fistulae (AVF) and arteriovenous grafts (AVG) at a single center. Fifty-eight BVT were placed in 57 individuals, 69% after prior vascular access failure. Ten BVT failed before initial use and 2 patients expired with functioning accesses before dialysis initiation. In all 58 BVT, 46.8+/-10.8% functioned at 3 years, with median survival 30.8 months. Limiting analyses to the 46 BVT that were ultimately accessed, 3-year primary and secondary patency rates were 38.3+/-7.7% and 56.5+/-12.6%, respectively. Lower ejection fraction (p=0.054) and greater numbers of prior permanent dialysis catheters (p=0.005) were present in those with failed BVT. Compared with AVF, BVT had similar 3-year primary and secondary patency rates. The secondary patency rate was significantly better for BVT vs. AVG over the observation period; at 3 years, the rates were 56.5+/-12.6% vs. 9.1+/-6.0% (p=0.002), respectively. Basilic vein arteriovenous fistulae are valuable hemodialysis accesses. Although nearly 20% of newly placed BVT will not function before first use, those that are functional have median survivals exceeding 6 years, and 38% will not require intervention within 3 years of initial use.     

Hypoproteinemia as a prognostic risk factor for arteriovenous fistula failure

Introduction: Any vascular access is of limited duration with many factors which influence survival in patients on chronic hemodialysis (HD). Hypoproteinemia as a marker of chronic illness is common among chronic HD patients. Our aim was to analyze the survival of the primary arteriovenous fistula (AVFs) and the risk factors which influence their patency and to test the hypothesis that patients with normal values of serum proteins have lower risk of AVF failure compared to patients with hypoproteinemia. Methods: Seven hundred thirty‐four consecutive patients were included who underwent creation of an AVF. The patients were prospectively followed‐up for 2 years. Only patients with AVF function after a month from its creation were analyzed. The patients were divided into two subgroups, with normal and low serum protein levels (<65 g/L). Findings: At follow‐up 497 (67.7%) AVFs were still functional while 237 (32.3%) AVFs failed due to thrombosis or stenosis. Serum proteins and AVFs created on the forearm were positive predictors while diabetes was a negative predictor of longer AVF survival (P < 0.001; P = 0.003; P = 0.043). When comparing patients with normal and low serum protein levels (<65 g/L), mean survival time was significantly longer in patients with normal serum levels (P < 0.001). Discussion: In this study, hypoproteinemia was an independent prognostic marker for AVF failure at 2 years. Hypoproteinemia, based on our results, is an independent, more sensitive and prognostic marker of possible vascular access failure than the presence of other common factors which influence shorter AVF survival.     

Barriers,biases, and beliefs about arteriovenous fistula placement in children: A survey of the International Pediatric Fistula First Initiative (IPFFI) within the Midwest Pediatric Nephrology Consortium (MWPNC)

There has been recent emphasis on increased arteriovenous fistula (AVF) use and decreased central venous catheter use in hemodialysis (HD) patients. The International Pediatric Fistula First Initiative was founded via collaborative effort with the Midwest Pediatric Nephrology Consortium to alert nephrologists, surgeons, and dialysis staff to consider fistulae as the best access in pediatric HD patients. A multidisciplinary educational DVD outlining expectations and strategies to increase AVF placement and usage in children was created. Participants were administered a survey previewing and postviewing to identify barriers to placement and usage of AVF in children. A total of 52 surveys were subdivided as either “dialysis staff” or “proceduralist” at five centers. Thirty‐three percent of respondents were unaware if their practice was following published guidelines. Sixty‐five percent of respondents stated they referred to a dedicated vascular access surgeon at their respective institutions. Methods used to monitor AVF function included physical exam, venous pressure monitoring, and ultrasound dilution. Vascular access was placed within 3 months in only 35% of patients. Interdisciplinary communication problems between surgeons, interventional radiologists, and nephrologists were identified as a major barrier. Lack of AVF usage was often due to maturation failure. Routine access rounds did not occur in any centers. Regarding monitoring, 74% of the respondents use physical exam, 26% use venous pressure monitoring, and 9% use ultrasound dilution. Ninety‐three percent of dialysis staff stated they would change practice patterns following the intervention; however, 12% of surgeons stated they would alter practice patterns. To our knowledge, this is the first report to identify barriers to placement of AVF in children from the perspectives of multidisciplinary team members including pediatric nephrologists, surgeons, interventional radiologists, and multidisciplinary dialysis staff.     

Long-term patency of arteriovenous fistulas for hemodialysis: A decade's experience in a transplant unit

Background

The heterogeneous quality of studies on arteriovenous fistulas outcome, with variable clinical settings and large variations in definitions of patency and failure rates, leads to frequent misinterpretations and overestimation of arteriovenous fistula patency. Hence, this study aimed to provide realistic and clinically relevant long-term arteriovenous fistula outcomes.

Methods

We retrospectively analyzed all autologous arteriovenous fistulas at our center over a 10-year period (2012–2022). Primary and secondary patency analysis was conducted using the Kaplan–Meier method; multivariate analysis of variance was used to detect outcome predictors. Vascular access-specific endpoints were defined according to the European guidelines on vascular access formation.

Findings

Of 312 arteriovenous fistulas, 57.5% (n = 181) were radio-cephalic (RC_AVF), 35.2% (n = 111) brachio-cephalic (BC_AVF), and 6.3% (n = 20) brachio-basilic (BB_AVF). 6, 12, and 24 months follow-up was available in 290 (92.1%), 282 (89.5%), and 259 (82.2%) patients, respectively. Primary patency rates at 6, 12, and 24 months were 39.5%, 34.8%, and 27.2% for RC_AVF, 58.3%, 44.4%, and 27.8% for BC_AVF, and 40.0%, 42.1%, and 22.2% for BB_AVF (p = 0.15). Secondary patency rates at 6, 12, and 24 months were 65.7%, 63.8%, and 59.0% for RC_AVF, 77.7%, 72.0%, and 59.6% for BC_AVF, and 65.0%, 68.4%, and 61.1% for BB_AVF (p = 0.29). Factors associated with lower primary and secondary patency were hemodialysis at time of arteriovenous fistula formation (p = 0.037 and p = 0.024, respectively) and higher Charlson Comorbidity Index (p = 0.036 and p < 0.001, respectively). Previous kidney transplant showed inferior primary patency (p = 0.005); higher age inferior secondary patency (p < 0.001).

Discussion

Vascular access care remains challenging and salvage interventions are often needed to achieve maturation or maintain patency. Strict adherence to standardized outcome reporting in vascular access surgery paints a more realistic picture of arteriovenous fistula patency and enables reliable intercenter comparison.     

The flow field near a venous needle in hemodialysis: A computational study

The vascular access used in hemodialysis can suffer from numerous complications, which may lead to failure of the access, patient morbidity, and significant costs. The flow field in the region of the venous needle may be a source of damaging hemodynamics and hence adverse effects on the fistula. In this study, the venous needle flow has been considered, using three‐dimensional computational methods. Four scenarios where the venous needle flow could potentially influence dialysis treatment outcome were identified and examined: Variation of the needle placement angle (10°, 20°, 30°), variation of the blood flow rate settings (200, 300, 400 mL/min), variation of the needle depth (top, middle, bottom), and the inclusion of a back eye in the needle design. The presence of the needle has significant effect on the flow field, with different scenarios having varying influence. In general, wall shear stresses were elevated above normal physiological values, and increased presence of areas of low velocity and recirculation—indicating increased likelihood of intimal hyperplasia development—were found. Computational results showed that the presence of the venous needle in a hemodialysis fistula leads to abnormal and potentially damaging flow conditions and that optimization of needle parameters could aid in the reduction of vascular access complications. Results indicate shallow needle angles and lower blood flow rates may minimize vessel damage.     

Higher arteriovenous fistulae blood flows are associated with a lower level of dialysis-induced cardiac injury

Native arteriovenous fistulae (AVF) remain the vascular access of choice for hemodialysis (HD). Despite being associated with superior long-term outcomes (cf. catheter use), little is known about the systemic hemodynamic consequences of AVFs. Repetitive myocardial injury (myocardial stunning) is an under-recognized common consequence of HD. The aim of this study was to examine the impact of AVF flow (Qa) on dialysis-induced cardiac injury. We studied 50 chronic HD patients. All patients underwent echocardiography (and subsequent quantitative offline analysis) at baseline, during and post dialysis, to assess left ventricular function and the development of regional wall motion abnormalities. Qa was measured using ionic dialysance. Patients were divided into Qa tertiles (<500, mean 291±101 mL/min, 500–1000, mean 739±130 mL/min and >1000, mean 1265±221 mL/min). There were no significant differences between the groups in terms of age, sex, diabetes, or resting ejection fraction. Patients with Qa>1000 mL/min had a lower prevalence of left ventricular hypertrophy (55% vs. 76%, P=0.01). Dialysis-induced myocardial stunning (seen in 65% of the patients studied) was significantly and sequentially reduced in those patients with higher Qas. This was seen in a lower number of segments and ventricular regions developing regional wall motion abnormalities, as well as a significantly reduced mean and cumulative percentage reduction in fractional shortening of those ventricular segments affected (−187±37%, −161±26%, and −101±25%, respectively, P=0.04). Relatively higher AVF flows appear to be associated with a lower level of observed HD-induced cardiac injury.     

Vascular access‐related infection in nocturnal home hemodialysis

Frequent hemodialysis is associated with increased vascular access adverse events. We hypothesized that bacteremia would be more frequent in patients with central venous catheter (CVC) than arteriovenous fistula or arteriovenous graft (AVF/AVG) in nocturnal home hemodialysis (NHHD). We reviewed blood culture reports and concurrent clinical data for a cohort of one hundred eighty‐seven NHHD patients between January 1, 2006 and June 30, 2012. The primary outcome was time to first bacteremia, technique failure, or death after commencing NHHD. Types of bacteremia and clinical consequences were analyzed. Analyses were adjusted for a priori defined confounders. One hundred eighty‐seven patients were included with a total follow up of six hundred five patient years. Initial vascular access was AVF in seventy‐eight (42%) patients, AVG in eleven (6%) patients, and CVC in ninety‐eight (52%) patients. A total of 79.3% of patients with a CVC reached the composite endpoint of bacteremia, technique failure, or death in the study period; 44.5% of patients with an AVF or AVG reached this composite endpoint. Adjusted time to first bacteremia, technique failure, or death was significantly shorter in patients with initial CVC access (hazard ratio 2.42, 95% confidence interval 1.50–3.90, p < 0.001). Risk factors for bacteremia were comorbid status quantified by the Charlson Comorbidity Index (p < 0.001) and diabetes (p < 0.001). Coagulase negative staphylococcus was the commonest organism cultured accounting for 51.4% bacteremias. The second commonest organism was staphylococcus aureus (20.3% bacteremias). Patients undergoing NHHD with a CVC have a shorter duration to first infection, technique failure, or death than those with permanent vascular access.     

Usefulness of assisted procedures for arteriovenous fistula maturation without compromising access patency

Introduction: To increase the rate of arteriovenous fistula (AVF) use, assisted procedures for immature AVF have been strenuously performed. However, this is controversial in that an AVF matured by these assisted procedures may require more frequent intervention to maintain its patency, and have decreased long‐term patency. Methods: Eighty four AVFs that were matured with assisted maturation procedures and 266 AVFs that matured spontaneously without intervention, created between November 2009 and March 2013 from the hemodialysis (HD) vascular access (VA) cohort, were compared retrospectively and we also investigated the factors that may influence AVF long‐term patency. Median follow‐up was 26.8 months (interquartile range, 6.6–45.0 months). Findings: Access survival did not differ between AVFs matured by assisted procedures and spontaneously mature AVFs (P = 0.29). In multivariate Cox regression analysis of AVF survival, age (HR, 1.029; 95% CI, 1.004–1.056; P = 0.024), maturation without assisted procedures 4–6 weeks after AVF creation (HR, 0.233; 95% CI, 0.107–0.506; P < 0.001), and AVF thrombosis (HR, 26.511; 95% CI, 10.986–63.978; P < 0.001) were significantly associated with AVF survival. Performance of assisted procedures to induce AVF maturation did not influence AVF survival (HR, 0.437; 95% CI, 0.191–1.002; P = 0.05). Discussion: Our results support that idea that assisted maturation procedures can ensure the success of immature AVF without compromising long‐term patency. These procedures can be considered more positively for increasing AVF use for VA placement in HD patients.     

The long‐term effects of arteriovenous fistula creation on the development of pulmonary hypertension in hemodialysis patients

The aim of this prospective study was to evaluate long‐term effects of arteriovenous fistula (AVF) on the development of pulmonary arterial hypertension (PAH) and the relationship between blood flow rate of AVF and pulmonary artery pressure (PAP) in the patients with end‐stage renal disease (ESRD). This prospective study was performed in 20 patients with ESRD. Before an AVF was surgically created for hemodialysis, the patients were evaluated by echocardiography. Then, an AVF was surgically created in all patients. After mean 23.50 ± 2.25 months, the second evaluation was performed by echocardiography. Also, the blood flow rate of AVF was measured at the second echocardiographic evaluation. Pulmonary arterial hypertension was defined as a systolic PAP above 35 mmHg at rest. Mean age of 20 patients with ESRD was 55.05 ± 13.64 years; 11 of 20 patients were males. Pulmonary arterial hypertension was detected in 6 (30%) patients before AVF creation and in 4 (20%) patients after AVF creation. Systolic PAP value was meaningfully lower after AVF creation than before AVF creation (29.95 ± 10.26 mmHg vs. 35.35 ± 7.86 mmHg, respectively, P: 0.047). However, there was no significant difference between 2 time periods in terms of presence of PAH (P>0.05). Pulmonary artery pressure did not correlate with blood flow rate of AVF and duration after AVF creation (P>0.05). In hemodialysis patients, a surgically created AVF has no significant effect on the development of PAH within a long‐term period. Similarly, blood flow rate of AVF also did not affect remarkably systolic PAP within the long‐term period.     

Effects of secondary amyloidosis on arteriovenous hemodialysis fistula outcomes and intradialytic hypotension: a case-control study

Amyloid fibrils can affect vascular structure through deposition and by causing nitric oxide depletion and increase of asymmetric dimethyl arginine. Patients with amyloidosis are prone to development of hypotension. Hypotension may also affect the maturation of arteriovenous fistula (AVF) and may set the stage for formation of thrombosis and fistula failure. Thus, we aimed to evaluate effects of secondary amyloidosis on AVF outcomes and intradialytic hypotension. This is a case‐control study which included 20 hemodialysis patients with amyloidosis and 20 hemodialysis patients without amyloidosis as control group. All patients underwent Doppler ultrasound of AVF. A thorough fistula history and baseline laboratory values along with episodes of intradialytic hypotension and blood pressure measurements were recorded. There was no difference between the groups regarding age, gender, body mass index, presence of comorbidities, hypertension, and drug use. Systolic and diastolic blood pressures were similar (119 ± 28/75 ± 17 and 120 ± 14/75 ± 10 mmHg for patients with and without amyloidosis, respectively). Intradialytic hypotension episodes were also similar. Patients with amyloidosis had significantly lower serum albumin and higher C‐reactive protein values compared to control hemodialysis patients. AVF sites and total number of created fistulas were similar in both groups. Flow rates of current functional AVFs were not different between the groups (1084 ± 875 and 845 ± 466 mL/minute for patients with and without amyloidosis, respectively, p:0.67). Patency duration of first AVF was not different between the groups. Clinical fistula outcomes and rate of intradialytic hypotension episodes were not significantly different between patients with and without secondary systemic amyloidosis.     

Femoral arteriovenous fistula 3 months after removal of catheter for hemodialysis

A 56‐year‐old Asian woman was admitted to hospital for the consideration of hemodialysis (HD). A right femoral dialysis catheter was inserted for HD. Three months after removal of catheter, she was admitted because of right inguinal swelling. A thrill and bruit were felt and heard at the inguinal area. Color Doppler detected a fistula between right superficial femoral artery and right common femoral vein and subsequently confirmed by contrast enhanced computed tomography scan and 3‐dimensional reconstruction with computed tomography. At surgery, a 4‐mm–diameter fistula was found between the right superficial femoral artery and right common femoral vein. A primary closure of both defects in the artery and vein was then carried out. A follow‐up digital vascular study 3 months after surgical repair was normal. In conclusion, nephrologist should have a heightened awareness to the potential of this complication and should at least document a normal exam following the removal of femoral catheters.     

Hemodialysis access at initiation in the United States, 2005 to 2007: Still "Catheter First"

Despite the broad consensus that native arteriovenous fistula is the access of choice for hemodialysis, national-level information about vascular access at dialysis initiation has been unavailable in the United States. For incident hemodialysis patients, June 2005 to October 2007 (n=220,157), vascular access type was determined from the new Centers for Medicare & Medicaid Services Medical Evidence Report (form CMS-2728). Proportions with each type at first dialysis, demographic and clinical associations of each type, and associations between initial access type and survival were assessed. The mean patient age was 63.6 years; 29.4% of patients were African American, and for 44.5%, end-stage renal disease was due to diabetes. Vascular access proportions were: fistula, 13.2% of patients; graft, 4.3%; catheter/maturing fistula, 16.0%; catheter/maturing graft, 3.3%; and catheter alone, 63.2%. Adjusted odds ratios (vs. fistula) of catheter use alone were ≥1.50 for lack of insurance (1.62 [95% confidence interval 1.62–1.68]), nephrologist care for 0 to 12 months (2.75 [2.69–2.81]), other (2.19 [2.09–2.29]), or unknown (1.53 [1.44–1.63]) cause of renal disease, institutional residence (1.51 [1.45–1.57]), and 7 of 18 end-stage renal disease networks. Over a mean follow-up of 1 year, 26.0% of the study population died. Compared with fistula, adjusted mortality hazards ratios were 1.39 (1.32–1.47) for grafts, 1.49 (1.44–1.55) for catheters/maturing fistulas, 1.74 (1.65–1.84) for catheters/maturing grafts, and 2.18 (2.11–2.26) for catheters alone. While geographic variability is pronounced, vascular access at dialysis inception is typically suboptimal; suboptimal access exhibits a graded association with mortality. Lack of timely access to specialty care appears to limit optimal access.     

High‐output heart failure secondary to arteriovenous fistula

In the hemodialysis patient population, a surgically created arteriovenous fistula is the preferred vascular access option. Development of high‐output heart failure may be an underappreciated complication in patients who have undergone this procedure. When a large proportion of arterial blood is shunted from the left‐sided circulation to the right‐sided circulation via the fistula, the increase in preload can lead to increased cardiac output. Over time, the demands of an increased workload may lead to cardiac hypertrophy and eventual heart failure. Patients may present with the usual signs of high‐output heart failure including tachycardia, elevated pulse pressure, hyperkinetic precordium, and jugular venous distension. Typically, the AV fistula is quite large and is likely located in the upper arm, more proximal to the heart. Routine access flow monitoring should demonstrate blood flows (Qa) >2000 ML/min. Echocardiogram may reveal either a low or high left ventricular ejection fraction, and right‐heart catheterization demonstrates an elevated cardiac output with a low to normal systemic vascular resistance. When addressing the problem of high‐output heart failure, the nephrologist is faced with the dilemma of preventing progression of heart failure at the expense of loss of vascular access. Nevertheless, treatment should be directed at correcting the underlying problem by surgical banding or ligation of the fistula.     

Geographic disparities in arteriovenous fistula placement in patients approaching hemodialysis in the United States

Arteriovenous fistula (AVF) is the preferred vascular access for hemodialysis (HD). Several factors associated with AVF placement have been identified (e.g., age, sex, race, comorbidities). We hypothesized that geographic location of patient residence might be associated with the probability of AVF placement as the initial access. We used the data from the United States Renal Data System (USRDS) database (2005–2008) linked to Medicare claims (2003–2008). Logistic regression was used to estimate specific characteristics of population associated with the AVF as first access placed or attempted for HD initiation. Our primary variable of interest was the geographic location, and the multivariate model was adjusted for age, sex, race, body mass index, primary cause of end‐stage renal disease (ESRD), duration of pre‐ESRD nephrology care, comorbidities, employment status, substance abuse, and income. Geographic location was determined using the data collected by the RUCA project and divided population into metropolitan, micropolitan, and rural categories. Patients (n = 111,953) identified from the USRDS database with linked Medicare claims were examined. Rates of fistula placement in the metropolitan, micropolitan, and rural population were 18.5%, 22.4%, and 21.6%, respectively. In comparison, patients who received catheter as the first access were 81.5%, 77.6% and 78.4%, respectively. The odds ratio of AVF placement as a first HD access in the rural and metropolitan population compared with the micropolitan population were 0.96 (0.90–1.03; P = 0.26) and 0.80 (0.76–0.84; P < 0.001), respectively. Our results indicate the presence of geographic disparities in AVF placement with decreased rates of AVF as the first access created in the metropolitan (but not rural) populations compared with the micropolitan communities.     

Endophthalmitis: a rare complication of arteriovenous fistula infection

Vascular access infection is a frequent problem in patients undergoing maintenance hemodialysis. Infection of arteriovenous fistula (AVF) is less common than dialysis catheter-associated infection. Previous case reports described endophthalmitis secondary to hemodialysis catheter-related infection, but not secondary to native AVF infection. We report a rare patient of endophthalmitis as a metastatic infection of AVF cannulation site abscess. A 19-year-old girl on maintenance hemodialysis for the past 2 years has presented with a history of fever, chills, and rigor of 3-days duration and painful dimness of vision in the left eye of 1-night duration. It was followed by redness of the eye, photophobia, and ocular discharge. On examination, the patient was febrile with an abscess near cannulation site of AVF. There was no perception of light in the left eye, conjunctiva was congested, cornea was clear, hypopyon present, and pupil was mid-dilated, not reacting to light. Lens was clear. Vitreitis and exudative retinal detachment was present. Methicillin sensitive Staphylococcus aureus was isolated from blood, pus from AVF abscess and vitreous fluid. Diagnosis of endophthalmitis was confirmed by B-scan ultrasound. She was treated with both intravenous and intraocular antibiotics and drainage of pus from AVF abscess and therapeutic vitrectomy. Though arteriovenous abscess responded to sensitive antibiotics and drainage, vision has not improved much. Strict aseptic precautions during regular AVF cannulation are required. Lapses may lead to loss of vision apart from described complications like access closure, endocarditis, and osteomyelitis.     

Improving arteriovenous fistula rate: Effect on hemodialysis quality

Vascular access (VA) is the lifeline for patients with end‐stage renal disease on regular hemodialysis (HD). Tunneled catheters have been associated with increased risk of luminal thrombosis, infection, hospitalization, and high cost. Our aims were to follow the “Fistula First Initiative,” avoid or reduce the rate of catheter insertion, improve the rate of arteriovenous fistula (AVF) use, and study the effect of increased AVF use on quality of dialysis and patient's outcome. A VA program has been established in collaboration with an enthusiastic and professional vascular surgery team to manage 358 patients who have been on regular HD treatment for a period ranging from 1 to 252 months. The mean ± standard deviation age of patients was 52 ± 15 years with 62% male patients. Over a period of 2 years, 408 procedures were performed. These include 293 AVFs and 56 arteriovenous grafts (AVGs). Other procedures include 39 permanent catheter insertions, 8 AVF aneurysmectomy, removal of 6 AVGs, embolectomy of 4 AVGs, excision of 1 AVG lymphocele, and ligation of 1 AVF. This program resulted in significant increase in AVF rate from 35% to 82%; reduction in catheter rate from 62% to 10.9%; infection rate down from 6.6% to 0.6%; VA clotting down from 5.1% to 1.0%; and increase in average blood flow rate from 214 ± 32 to 298 ± 37 mL/min (P < 0.01). These results have been associated with improved average single pool Kt/V from 0.88 ± 0.19 to 1.28 ± 0.2 (P < 0.01); increased hemoglobin from 9.2 ± 1.2 to 10.9 ± 0.9 g/dL (P < 0.01); improved serum albumin from 3.2 ± 0.5 to 3.7 ± 0.4 g/dL (P < 0.05); reduction in administered erythropoietin dose by 19%; and significant drop in hospitalization rate from 6.1% to 3.8%. These results confirm the great benefits of AVF on quality of HD and patient outcome, and clearly affirm that AVF should always be considered first.