Arteriovenous Fistula Group Research Articles

Arteriovenous Vascular Access–Related Procedural Burden Among Incident Hemodialysis Patients in the United States

As the proportion of arteriovenous fistulas (AVFs) compared with arteriovenous grafts (AVGs) in the United States has increased, there has been a concurrent increase in interventions. We explored AVF and AVG maturation and maintenance procedural burden in the first year of hemodialysis. Observational cohort study. Patients initiating hemodialysis from July 1, 2012, to December 31, 2014, and having a first-time AVF or AVG placement between dialysis initiation and 1 year (N= 73,027), identified using the US Renal Data System (USRDS). Patient characteristics. Successful AVF/AVG use and intervention procedure burden. For each group, we analyzed interventional procedure rates during maturation maintenance phases using Poisson regression. We used proportional rate modeling for covariate-adjusted analysis of interventional procedure rates during the maintenance phase. During the maturation phase, 13,989 of 57,275 patients (24.4%) in the AVF group required intervention, with therapeutic interventional requirements of 0.36 per person. In the AVG group 2,904 of 15,572 patients (18.4%) required intervention during maturation, with therapeutic interventional requirements of 0.28 per person. During the maintenance phase, in the AVF group 12,732 of 32,115 patients (39.6%) required intervention, with a therapeutic intervention rate of 0.93 per person-year. During maintenance phase, in the AVG group 5,928 of 10,271 patients (57.7%) required intervention, with a therapeutic intervention rate of 1.87 per person-year. For both phases, the intervention rates for AVF tended to be higher on the East Coast while those for AVG were more uniform geographically. This study relies on administrative data, with monthly recording of access use. During maturation, interventions for both AVFs and AVGs were relatively common. Once successfully matured, AVFs had lower maintenance interventional requirements. During the maturation and maintenance phases, there were geographic variations in AVF intervention rates that warrant additional study.

Effect of the tunneled-cuffed central venous catheters on oxidative stress indices and inflammation in chronic hemodialysis patients

Objectives: The use of central venous catheters as hemodialysis (HD) vascular access is associated with worse morbidity and mortality in HD patients. This occasion is often attributed to comorbidities of the patients with central venous catheters. Studies reveal that a biofilm layer occurs on most of the tunneled-cuffed central venous catheters (TC-CVCs). This study aimed to determine the oxidative stress (OS) and systemic inflammation (SI) status in patients with TC-CVCs as HD vascular access without clinical signs and symptoms of infection. Methods: The study is composed of eighty-five patients with a minimum HD vintage of one year. Patients with a history of infection or a cardiovascular event within six months, malignancy, systemic inflammatory diseases, or malnutrition were excluded. OS indices and SI markers were studied and compared in patients with arteriovenous fistula (AVF) and TC-CVCs. Results: Mean native thiol/total thiol (NT/TT) ratio was significantly higher and mean disulphide/total thiol (DT/TT) ratio was significantly lower in AVF group comparing TC-CVC group (0.46 ± 0.17 and 0.36 ± 0.17, p = 0.03 for NT/TT; 0.27 ± 0.08 and 0.31 ± 0.08, p = 0.04 for DS/TT; respectively). Mean OS index was significantly lower in the AVF group comparing TC-CVC group (0.15 ± 0.14 and 0.24 ± 0.23, p = 0.04; respectively]. Median hs-CRP levels and median IL-6 levels were significantly lower in AVF group comparing TC-CVC group (5.8 [min: 3.0-max: 82.5] mg/L and 9.7 [min: 3.0-max: 45.4] mg/L, p = 0.004 for hs-CRP; 6.2 [min: 2.0-max:159.0] pg/mL and 12.2 [min: 2.6-max: 41.3) pg/mL, p = 0.01 for IL-6; respectively). Conclusions: TC-CVCs inversely affect OS and systemic inflammatory status in HD patients, presumably due to foreign body reactions and biofilm layers.

Comparison of Ellipsys Percutaneous and Proximal Forearm Gracz-Type Surgical Arteriovenous Fistulas

Percutaneous arteriovenous fistulas (AVF) are created by establishing a proximal forearm anastomosis and offer a safe and reliable vascular access. This study compares the Ellipsys percutaneous AVF with a proximal forearm Gracz-type surgical AVF, chosen for comparison as it is constructed at the same anatomical site. Retrospective study of prospectively collected clinical data. All vascular access procedures conducted during a 34-month period were reviewed. The study groups comprised 89 percutaneous AVFs and 69 surgical AVFs. Percutaneous or surgical AVF placement. AVF patency, function, and complications. Patency rates for each AVF group were evaluated by competing risk survival analysis using a cumulative incidence function. Association of primary, primary assisted, and secondary patency with the AVF groups was examined by Cox proportional hazard models. Technical success was 100% for both groups. Average procedure times were 14 minutes for percutaneous AVFs and 74 minutes for surgical AVFs (P< 0.001). Proximal radial artery (PRA) was used in all percutaneous AVF cases. Inflow for surgical AVFs included radial (30%), ulnar (12%), and brachial (58%) arteries. Outflow veins for both groups were the cephalic and/or basilic veins. Access flow volumes, times to maturation, and overall numbers of interventions per patient-year were not significantly different. Cumulative incidence of primary patency failure at 12 months was lower for surgical AVF (47% vs 64%, P= 0.1), but secondary patency failure was not different between groups (20% vs 12%, P= 0.3). PRA surgical AVFs had similar primary patency (65% vs 64%, P= 0.8) but higher secondary patency failure rates than percutaneous AVFs at 12 months (34% vs 12%, P= 0.04). Retrospective study with a relatively short follow-up period, and not all patients required hemodialysis at the end of study. Both percutaneous and surgical AVFs demonstrated high rates of technical success and secondary patency. Percutaneous AVFs required shorter procedure times. The rate of intervention was similar. When a distal radial artery AVF is not feasible, percutaneous AVF might offer an appropriate procedure for creating a safe and functional access, maintaining further proximal forearm surgical AVF creation options.

Arteriovenous Fistula Versus Graft Access Strategy in Older Adults Receiving Hemodialysis: A Pilot Randomized Trial

BackgroundIt is unclear whether surgical placement of an arteriovenous (AV) fistula (AVF) confers substantial clinical benefits over an AV graft (AVG) in older adults with end-stage kidney disease (ESKD). We report vascular access outcomes of a pilot clinical trial.Study DesignPilot randomized parallel-group open-label trial.Setting & ParticipantsPatients 65 years and older with ESKD and no prior AV access receiving maintenance hemodialysis through a tunneled central venous catheter referred for AV access placement by their treating nephrologist.InterventionParticipants were randomly assigned in a 1:1 ratio to surgical placement of an AVG or AVF.OutcomesIndex AV access primary failure, successful cannulation, adjuvant interventions and infections.ResultsOf 122 older adults receiving hemodialysis and no prior AV access surgery, 24% died before (n = 18) or were too sick for (n = 11) referral for a permanent AV access. Of 46 eligible patients, 36 (78%) consented and were randomly assigned to AVG (n = 18) and AVF (n = 18) placement, of whom 13 (72%) and 16 (89%) underwent index AV access surgical placement, respectively. At a median follow-up of 321.0 days, primary AV access failure was noted in 31% in each group. The proportion of patients with successful cannulation was 62% (8 of 13) in the AVG and 50% (8 of 16) in the AVF group; median times to successful cannulation were 75.0 and 113.5 days, respectively. Endovascular procedures were recorded in 38% and 44%, and surgical reinterventions, in 23% and 25%, respectively. AV access infection was seen in 3 (23%) and 2 (13%) patients, respectively.LimitationsSmall sample size precludes statistical inference.ConclusionsAlmost one-quarter of older adults with incident ESKD and a central venous catheter as primary access were not referred for AV access placement due to medical reasons. Based on these limited results, there is little reason to favor either an AVF or AVG in this population until results from a larger randomized clinical trial become available.FundingGovernment funding to an author (Dr Murea is supported by National Institutes of Health∖National Institute on Aging grant 1R03 AG060178-01).Trial RegistrationNCT03545113.

Arteriovenous Fistula Creation and Estimated Glomerular Filtration Rate Decline in Advanced CKD: A Matched Cohort Study.

Kidney failure is associated with a high burden of morbidity and mortality. Previous studies have raised the possibility that arteriovenous fistula (AVF) creation may attenuate eGFR decline. This study aimed to compare eGFR decline in predialysis patients with an AVF, matched to patients oriented toward peritoneal dialysis (PD). Predialysis patients with an AVF and those oriented toward PD were retrospectively matched using a propensity score. Time zero was defined as the "AVF creation date" for the AVF group and the "date when eGFR was closest to the matched patient's eGFR at AVF creation" for the PD group. Crude and predicted eGFR decline in AVF and PD groups were compared before and after time zero using mixed-effect linear regressions. In total, 61 pairs were matched. Crude annual eGFR decline before AVF creation/time zero was -4.1 ml/min per m2 per year in the AVF group versus -5.3 ml/min per m2 per year in the PD group (P=0.75) and after time zero, -2.5 ml/min per m2 per year in the AVF group versus -4.5 ml/min per m2 per year in the PD group (P=0.02). The predicted annual decline decreased from -5.1 ml/min per m2 per year in the AVF group before AVF creation to -2.8 ml/min per m2 per year after (P<0.01), whereas there was no difference in the PD group (-5.5 versus -5.1 ml/min per m2 per year respectively, P=0.41). In this matched study, AVF creation was associated with a deceleration of kidney function decline compared with a control PD-oriented group. Prospective studies are needed to assess the potential mechanisms between vascular access creation and eGFR slope attenuation.

Predictors associated with early and late restenosis of arteriovenous fistulas and grafts after percutaneous transluminal angiography

BackgroundThe objective of this study was to assess postintervention patency and analyze the predictive factors associated with early and late restenosis after intervention in hemodialysis arteriovenous fistulas (AVF) and arteriovenous grafts (AVG).MethodsThis study retrospectively analyzed 284 hemodialysis patients who underwent percutaneous transluminal angioplasty (PTA) due to AVF and AVG stenosis. A total of 350 PTA procedures were performed. Clinical, anatomical, biochemical, and technical variables were analyzed. Using univariate and multivariate analyses, we assessed the postintervention patency of PTA by follow-up, and identified the predictive factors taking into account competing risks.ResultsPostintervention patency rates at 3, 6, 12, and 24 months were 86.5%, 66.4%, 42.6%, and 29.8%, respectively, with a median patency duration of 11±0.71 months. Kaplan-Meier analysis showed that the patency rate of the AVF group (n=271) was dramatically higher than the AVG group (n=79) at 3, 6, and 12 months after PTA, respectively (88.9% vs. 78.5%, 69.0% vs. 57.4%, 48.8% vs. 20.0%, P<0.01). Cox survival analysis revealed that the factors associated with postintervention patency of AVF included age of fistulas, serum albumin (ALB) levels, location of stenoses, lesion length longer than 2 cm, multiple stenoses, and maximal pressure of dilatation lower than 16 atm. In addition, factors related to postintervention patency of AVG included the presence of diabetes and hypertension, and serum ALB.ConclusionsThis study demonstrated that the risk factors associated with postintervention patency of AVF included age of fistulas, lower levels of serum ALB, location of stenoses, lesion length longer than 2 cm, multiple stenoses, and maximal pressure of dilatation lower than 16 atm. In addition, risk factors related to postintervention patency of AVG included the presence of diabetes and lower levels of serum ALB, while the presence of hypertension was found to be a protective factor for reducing patency loss of AVG. Among all these factors, serum ALB and multiple stenoses tended to predict early restenosis, while pressure of dilatation tended to predict late restenosis.

Micro-Rheological Changes of Red Blood Cells in the Presence of an Arterio-Venous Fistula or a Loop-Shaped Venous Graft in the Rat.

Introduction: In case of kidney failure, hemodialysis is the primary kidney replacement technique. Several vascular access methods used for the therapy, one of which is the arterio-venous fistula (AVF). In the AVF, the blood flow is altered, which can elevate the mechanical stress on the red blood cells (RBCs). This can affect the RBC hemorheological properties, and it can further cause systemic changes. To lower the turbulence and shear stress, we performed a loop-shaped arterio-arterial venous interposition graft (loop-shaped graft) to compare its effect to the conventional AVF.Materials and Methods: Thirty male Wistar were used (permission registration Nr.: 25/2016/UDCAW). The animals were randomly divided into sham-operated, AVF, and loop groups (n = 10/each). The superficial inferior epigastric vein (SIEV) was used to create the AVF and the loop-shaped graft. Blood samples were taken before/after the surgery and at the 1st, 3rd, and 5th postoperative weeks. We measured hemorhelogical, hematological, and blood gas parameters. The microcirculation of the hind limbs was also monitored using Laser Doppler fluxmetry.Results: Hematocrit, RBC count, and hemoglobin decreased by the 1st postoperative week. The erythrocyte aggregation values significantly increased in the fistula group by the 5th week (6.43 ± 2.31 vs. 13.60; p < 0.0001; vs. before operation). At the postoperative 1st week in the loop group, the values showed a significant decrease in RBC deformability. During the maturation period, dominantly at the 5th week, all values were normalized. The operated hind limb’s skin microcirculation significantly increased in the sham and loop group by the 1st week (39 ± 10.57 vs. 73.93 ± 1.97 BFU, p < 0.01). This increase wasn’t observed in the fistula group probably due to a steal-effect.Conclusion: Unlike in the loop group, in the presence of the fistula, several rheological parameters have changed. The loop-shaped graft had only minimal impact on micro-rheological parameters.

Perioperative Opioid and Nonopioid Prescribing Patterns in AVF/AVG Creation

To evaluate postoperative opioid prescribing patterns in patients undergoing hemodialysis access creation. Operative logs were reviewed to identify patients undergoing creation of arteriovenous fistula (AVF) or graft (AVG) from September 2016 to January 2018. Immediate postoperative opioid prescriptions were compared for ambulatory patients versus inpatients. Opioid prescriptions at the time of discharge for inpatients were recorded. Rates of opioid prescribing were standardized by conversion to morphine milligram equivalents (MMEs). Opioid use postoperatively and at the time of discharge based on anesthetic technique, general anesthesia versus regional or local anesthesia with sedation were compared. Alternative pain medications administered and pain scores were recorded. Comparisons were made between the percentage of opioid use and doses administered between AVF and AVG patient groups, ambulatory and inpatients, and type of anesthetic technique used. Statistical analysis was performed with chi-square and t-tests. We identified 164 patients undergoing AV access creation but not receiving chronic opioid therapy. A significantly higher percentage of inpatients received opioids in the immediate postoperative period than ambulatory patients (AVF: 72% vs. 19%, P<0.001; AVG: 62% vs. 25%, P=0.001). Overall, all AVG patients were more likely to be discharged with an opioid prescription than all AVF patients (37% vs. 8%, P<0.001). Of AVG patients managed in the ambulatory setting, 48% were discharged with an opioid prescription. The mean total opioid postoperative dose prescribed to inpatients was significantly higher than that prescribed to ambulatory patients for both fistulas (28.73 MMEs vs. 1.27 MMEs, P<0.001) and grafts (22.11 MMEs vs. 2.16 MMEs, P=0.005). General anesthesia patient groups were more likely to receive opioids postoperatively than local anesthesia with sedation patients for both AVF (54% vs. 24%, P=0.027) and AVG creation (61% vs. 17% P<0.001). Postoperative alternative medication use in the hospital was low with 18% acetaminophen and 1% nonsteroidal anti-inflammatory drug use for AVF patient groups and 24% acetaminophen and 0% nonsteroidal anti-inflammatory drug use for AVG patient groups. The percentage of patients reporting postoperative pain in the recovery room and on the inpatient units was comparable between ambulatory and inpatient settings (AVF: 21% vs. 28%, P=0.534; AVG: 23% vs. 44%, P=0.061). A higher percentage of inpatients undergoing hemodialysis access received opioids when compared with ambulatory patients in the immediate postoperative period. Inpatients were prescribed higher mean doses than ambulatory patients. AVG patient groups were prescribed more opioids than AVF patient groups. Alternative analgesic agent use was low, suggesting an opportunity for improved pain control and opioid reduction. Dialysis access creation represents an opportunity to improve on opioid prescribing patterns.

P1318EPIDEMIOLOGY OF BLOODSTREAM INFECTIONS IN A SCOTTISH HAEMODIALYSIS POPULATION WITH FOCUS ON VASCULAR ACCESS METHOD

Abstract Background and Aims Haemodialysis (HD) vascular access infections account for approximately 28% of infection-associated hospitalisations in patients with end-stage renal disease1. Traditionally there has been focus on Staphylococcus aureus (S. aureus) infections, however there is increasing recognition of the burden of Gram-negative bloodstream infection (BSI) in the HD population2,3. Epidemiological analysis has enabled surveillance of the impact of antimicrobial protocols on BSI rate and outcome2. Scottish Registry data reflects that access methods are changing alongside the HD population phenotype, with increasing use of arterio-venous graft (AVG) and central venous catheters for incident and prevalent HD access3. In this study, the rate of BSI in a contemporary Scottish HD cohort is reported by microbial species and vascular access type: arterio-venous fistula (AVF), AVG, tunnelled central venous catheter (TCVC) or non-tunnelled central venous catheter (NTCVC). Method The Strathclyde Electronic Renal Patient Record (SERPR) database for the West of Scotland was utilised to obtain retrospective observational data all adult patients attending inpatient and outpatient renal services across seven dialysis units between 1st January 2017 and 31st December 2017. All BSIs were analysed as separate episodes if more than 14 days apart, regardless of the suspected source of infection, and expressed as events per 1000 HD days. The number of days each patient was exposed to each vascular access subtype was calculated utilising the prospectively recorded HD access observations. Prevalent HD vascular access type was noted for each BSI. Results There were 786 patients who underwent HD with 217 503 total HD days over the study period. A total of 147 separate BSIs occurred, involving 115 patients. A total of 168 organisms were encountered in these BSIs. There were 49 BSIs during 126, 674 HD days using AVF access, 14 BSIs during 25, 511 AVG HD days, 81 BSIs during 64, 353 TCVC HD days and 3 BSIs during 965 NTCVC HD days. Table 1 outlines the BSI rates by vascular access and organisms identified Staphylococci-related BSI comprised the majority of events (51.7%), with S. aureus implicated in 47% of these BSIs. Coagulase-negative staphylococci were the most commonly identified organisms in the AVF, TCVC and NTCVC groups, with S. aureus the leading organism in the AVG group. Gram-negative organisms accounted for the next largest proportion of BSIs (27%) and were more prevalent in the TCVC and NTCVC groups. Conclusion AVF access subtype was associated with the lowest BSI rate, and NTCVC the highest which is in keeping with previous studies and one of the drivers for AVF as the preferred HD access type internationally. Staphylococci continue to represent a large proportion of BSIs in this cohort, however other organisms are prevalent. BSIs caused by Gram-negative organisms and Candida species were represented more heavily in the TCVC and NTCVC population, perhaps representing co-morbidity of these groups.

Comparison of vascular access patency and patient survival between native arteriovenous fistula and synthetic arteriovenous graft according to age group.

Arteriovenous fistula (AVF) is historically known to be the ideal option for vascular access (VA) for hemodialysis compared with arteriovenous graft (AVG). However, this approach has been recently questioned in the aging population because of their poor vessel quality and multiple comorbidities. Data from a total of 2200 patients from the VA category of The Catholic Medical Center nephrology registry from March 2009 to February 2017 were analyzed. We compared VA patency and patient survival between two groups, AVF and AVG, according to age. Compared with the AVG group, survival benefit in the AVF group continued even in patients ≥80 years. In the whole population, all the primary patency (PP), primary-assisted patency (PAP), and secondary patency (SP) measures were superior in the AVF group. With regard to subgroups, PP was comparable between the two groups in patients ≥65 years, whereas PAP and SP were superior in the AVF group even in septuagenarian patients who are from 70 to 79 years old. In patients ≥80 years, all the patency measures were comparable between the two groups. When the separate comparison of lower-arm AVF (or upper-arm AVF) and AVG, lower-arm AVF failed to demonstrate its superiority in any kind of patency in septuagenarian patients compared with AVG, whereas upper-arm AVF demonstrated its superiority in PAP and SP in septuagenarian patients. However, even upper-arm AVF failed to demonstrate its superiority in any kind of patency in patients ≥80 years. Arteriovenous fistula if using upper-arm vessel showed the superior VA patency up to septuagenarian patients, whereas, in HD patients ≥80 years, AVF and AVG were comparable in VA patency.

Impact of vascular access type on health-related quality of life in patients undergoing hemodialysis: A cross-sectional observational study

Objective: Patients undergoing hemodialysis (HD) have a poor health-related quality of life (HRQoL). HRQoL may differ across geography and ethnicity. This study aimed to compare HRQoL in patients undergoing HD by arteriovenous fistula (AVF) and central venous catheter (CVC) in a cohort of Indian population. Methods: This was a cross-sectional observational study conducted between March 2016 and June 2016. All patients undergoing HD (more than 2 months) who had vascular access using AVF or CVC were eligible to participate in the study. Sociodemographic characteristics were noted, and HRQoL was assessed using the Short Form 36 questionnaire. Results: A total of 58 patients were included in this study, 31 in CVC group and 27 in AVF group, without any crossover. The mean (standard deviation) age was 47.4 (18.1), and the median (range) duration of HD was 14 months (2 months–120 months).Overall, patients who underwent AVF for vascular access had significantly (P < 0.05) higher HRQoL score than those who underwent CVC. There was no significant difference of HRQoL score for majority of the parameters for sex and age, for all the parameters for duration of HD. Conclusions: Overall, results showed that patients who had vascular access using AVF showed better HRQoL as compared to CVC in patients with HD.

Relationship between bovine carotid artery grafts for hemodialysis access and human leukocyte antigen sensitization.

Bovine carotid artery (BCA) Artegraft is a biologic graft that can be utilized as a conduit for permanent hemodialysis access and has been shown to outperform polytetrafluoroethylene grafts. However, concern regarding immunologic sensitization may limit the use of BCA in the transplant candidate. Panel reactive antibody (PRA) is an immunological test utilized in transplant recipient selection whereas increases in PRA limit access to transplantation. The purpose of our study was to determine whether BCA graft placement was adversely associated with increases in PRA. Of patients listed for kidney transplant at our institution, we identified 10 patients who underwent BCA placement for hemodialysis access and a matched cohort of 10 patients who underwent native arteriovenous fistula (AVF) creation between 2014 and 2017. The PRA value nearest to the surgery date was compared to postsurgery PRA value for the BCA and AVF patients using a paired t test. Presurgery PRAs were also compared to the maximum PRA at 0 to 6, 6 to 12, 12 to 18, and 18 to 24 months postsurgery. Prior to the dialysis access operation, the mean PRA was 14.1% ± 23.5% vs. 17.1% ± 29.0% (P = 0.76) and the median postsurgery follow-up time was 16 and 15 months for BCA and AVF cohorts, respectively. There were no statistically significant differences between presurgery and postsurgery PRA for BCA and AVF patients, regardless of time interval postsurgery. The difference in presurgery/postsurgery PRA change between cohorts was not statistically significant for PRAs closest to surgery (0.2% ± 40.6% vs. 1.0% ± 2.8%, P = 0.95, at a median 4 and 3 months postsurgery, respectively) or when using the maximum in any postsurgery interval. Prior to their dialysis access surgery, there were 16 sensitizing events in 5 patients in the BCA group compared to 10 events in 5 patients in the AVF group (P = 0.20). Only 1 of the 10 patients in the BCA group had a clinically relevant and sustained increase in PRA following their dialysis access operation vs. no patients in the AVF group (P > 0.99). However, this patient had a known sensitizing event (blood transfusion) between the BCA surgery and the postoperative PRA. Three of 10 patients in the BCA cohort vs. 5 of 10 patients in the AVF cohort went on to have successful kidney transplants (P = 0.65). The utilization of BCA for dialysis access was not associated with statistically significant changes in PRA. These data suggest that implantation of BCA will not affect access to organ transplantation.

Dimethylarginine Dimethylaminohydrolase 1 Polymorphisms and Venous Intimal Hyperplasia in Hemodialysis Patients

Background: After angioplasty, veins are more prone to intimal hyperplasia than arteries. Veins tend to produce less nitric oxide (NO), which could lead to endothelial dysfunction. Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of NO synthase and contributes to cardiovascular disease. In humans, dimethylarginine dimethylaminohydrolase 1 (DDAH1) is the major enzyme for ADMA degradation. In this study, we aim to determine whether venous intimal hyperplasia in hemodialysis (HD) vascular access is influenced by common polymorphisms in the DDAH1 genes. Methods: This is a prospective observational cohort study. A total of 473 HD patients referred for the angioplasty of vascular access were enrolled. There were 190 arteriovenous grafts (AVG) and 283 arteriovenous fistulas (AVF). The follow-up lasted for 2 years after the interventions. Seven single nucleotide polymorphisms (SNPs) in DDAH1 were genotyped and ADMA were measured at baseline. The primary outcome was restenosis after angioplasty. Results: Among the 7 SNPs, plasma ADMA levels were significantly different in DDAH1 rs233112 (GA + GG vs. AA, 0.86 ± 0.23 vs. 0.82 ± 0.19 μM, p = 0.03) and rs1498373 (CT + TT vs. CC, 0.87 ± 0.23 vs. 0.82 ± 0.20 μM, p = 0.02) genotypes. The AVF group with GG + GA genotype of rs233112 and CT + TT genotype of rs1498373 had higher risks of early restenosis at 3 months. In the AVG group, only GG + GA genotype of rs233112 was associated with early restenosis. A combined analysis of AVG and AVF groups showed that patients with rs233112 GA + GG genotype and rs1498373 CT + TT genotype had higher risks of early restenosis (both p < 0.001). The multivariate analysis results showed that the association of these genotypes with early restenosis is independent of clinical, access, or biochemical factors. Conclusions: Our findings suggest that certain DDAH1 polymorphisms modulate circulating ADMA levels and are associated with venous intimal hyperplasia.

Percutaneous transluminal angioplasty combined with thrombolysis for acute thrombosis in arterio-venous fistula and graft

To evaluate the efficacy of ultrasound or fluoroscopic-guided percutaneous transluminal angioplasty (PTA) combined with thrombolysis for the treatment of acutely thrombosed arteriovenous fistula (AVF) or grafts (AVG). One hundred and ninety-two hemodialysed patients, in whom the thrombosed arterio-venous AVF or AVG developed less than 72 h and there were no contraindications for thrombolysis and PTA, underwent PTA combined with thrombolysis therapy in Sir Run Run Shaw Hospital of Zhejiang University from October 2014 to October 2017. Under ultrasound and/or fluoroscopic guidance, balloon catheter was introduced to thrombosis sites along a guide wire. Then the balloon was inflated and normal saline mixed with urokinase and heparin was injected for thrombolysis. After blood flow was restored, angioplasty was performed on vascular stenosed sites. A total of 274 endovascular interventional operations were performed for 192 patients. The procedure success rate was 98.2%, clinical success rate was 93.8%and complication rate was 1.46%. The post-intervention primary patency rates for AVF group were 87.4%, 76.7%and 63.9%at 3, 6 and 12 months, respectively; while the post-intervention secondary patency rates were 93.7%, 91.6%and 83.0%, respectively. The post-intervention primary patency rates for AVG group were 60.7%, 51.5%and 43.1%at 3, 6 and 12 months, while the post-intervention secondary patency rates were 82.7%, 77.1%and 70.8%, respectively. PTA combined with thrombolysis is an effective and safe therapeutic option for AVF and AVG thrombosis, which would prolong hemodialysis access and save vascular resources for hemodialyzed patients.

THE RELATIONSHIP BETWEEN DIALYSIS MODALITY, ARTERIOVENOUS FISTULA AND HEMODYNAMIC PARAMETERS OF ARTERIAL RESERVOIR-WAVE ANALYSIS

Objective: Arterial reservoir-wave analysis (RWA) is a new model of arterial hemodynamics that separates the arterial wave into reservoir pressure (RP) and excess pressure (XSP). Whether RWA parameters are different in hemodialysis (HD), as compared to peritoneal dialysis (PD), and whether any differences are due to the presence of an arteriovenous fistula (AVF) remains unknown. The aims of the present study were to examine the differences in RWA 1) in HD versus PD patients and 2) in all dialysis patients (HD+PD) without AVF versus HD patients with AVF. Design and method: In a cross-sectional analysis of prevalent PD (n = 53) and HD (n = 208) patients, RWA was performed using pressure approach applied to the carotid pressure, which was calibrated with mean arterial pressure and used as a surrogate for central pressure. Among HD patients, 115 patients used AVF as vascular access. Results: In HD patients, diastolic blood pressure (BP) was lower (69 ± 14 vs 77 ± 10, mmHg, p < 0.001), while systolic BP was identical, resulting in increased carotid pulse pressure (PP) (58 ± 22 vs 50 ± 22 mm Hg, p = 0.036). Carotid RP and XSP integrals were higher in HD patients (2.11 ± 0.91 vs 1.89 ± 0.94, p = 0.027; 0.48 ± 0.30 vs 0.39 ± 0.27, p = 0.009). While there were no significant differences in BP medication between groups. HD patients were older and had a higher prevalence of clinical comorbidities such as diabetes and established cardiovascular disease. However, analysis of data according to AVF status resulted in homogenous groups in terms of age and comorbidities. In AVF group, dialysis vintage was higher (median 2.3 vs 1.1 years, p < 0.001), diastolic BP lower (68 ± 13 vs 72 ± 13 mm Hg, p = 0.003), PP higher (59 ± 22 vs 54 ± 22, p = 0.061), and RP and XSP integrals were higher (2.2 ± 0.9 vs 2.0 ± 0.9, p = 0.048; 0.5 ± 0.3 vs 0.4 ± 0.3, p = 0.078). After adjustment for dialysis vintage, XSP was significantly higher in AVF group (p = 0.034). Conclusions: In HD patients, RP and XSP integral were higher as compared to PD patients, but these differences were mainly due to the presence of AVF.

Outcomes of initial hemodialysis vascular access in patients initiating dialysis with a tunneled catheter

BackgroundOur aim was to determine factors that influence time to removal of tunneled hemodialysis catheter (THC), probability of repeat vascular access creation, and time to repeat vascular access. MethodsThe Optum Clinformatics Data Mart claims database was queried from 2011 to 2017 for patients who initiated hemodialysis with a THC. Time from initial arteriovenous fistula (AVF)/graft (AVG) to THC removal and time to repeat AVF/AVG were analyzed using Cox proportional hazards. The likelihood of repeat AVF/AVG was analyzed using logistic regression. ResultsA total of 8941 vascular access met the inclusion criteria: 6913 (77%) AVF and 2028 (23%) AVG. Median follow-up was 595 days among AVF patients (range, 1-2543 days) and 579 days among AVG patients (range, 1-2529 days). Patients undergoing AVF were younger, more likely to be male, of white race, and obese. Patients undergoing AVF were also slightly less likely to have diabetes, cardiac arrhythmia, congestive heart failure, and peripheral vascular disease than patients undergoing AVG. At 90 days and at 180 days after index access creation, significantly more patients who underwent index AVG had their THC removed compared with patients who underwent index AVF. By day 365, 78% of patients in both AVF and AVG had their THC removed. A total of 2550 (28.5%) patients underwent a repeat vascular access creation during the follow-up period: 30% of index AVF and 24% of index AVG. At 90 days, 180 days, and 365 days, significantly more patients in the index AVF group underwent a repeat vascular access creation than those in the index AVG group. Multivariate analysis demonstrated a significant interaction between vascular access type and age ≥70 years (P < .001) for time to THC removal, likelihood of repeat vascular access, and time to repeat vascular access. In the age <70 group, patients who underwent AVG were 60% more likely to have a shorter time to THC, had a 50.4% lower odds of repeat vascular access, and were 47% more likely to have a longer time to repeat vascular access compared with patients who underwent index AVF. In the age ≥70 group, patients who underwent AVG were 98% more likely to have a shorter time to THC removal, had 69.7% lower odds of repeat vascular access, and were 66% more likely to have a longer time to repeat vascular access. ConclusionsCreation of AVG vs AVF significantly decreases the time to THC removal in dialysis-dependent patients, with a larger difference in patients aged ≥70 vs <70. Initial AVG was associated with lower odds of repeat vascular access and longer time to repeat vascular access. These results suggest that the dictum of “fistula first” is not appropriate for all patient populations and supports judicious use of AVG in achieving the more recent shift toward “catheter last.”

SS06. Efficacy of Surgical Correction of Dialysis Access Steal Syndrome

Surgical options to treat vascular access-related steal syndrome include distal revascularization-interval ligation (DRIL), proximalization of arterial inflow (PAI), access banding, and access ligation. The efficacy of these individual modalities in symptom resolution has not been previously reported. The aim of this study was to compare efficacy of different surgical modalities for treatment of steal associated with arteriovenous fistulas (AVFs) and arteriovenous grafts (AVGs). Retrospective analysis was performed on adults diagnosed with steal syndrome after hemodialysis access creation who underwent revision of their dialysis access by a singular vascular specialty group within one integrated health care system. Patients <18 years, those with lower extremity accesses, and those with HeRO grafts (Merit Medical, South Jordan, Utah) were excluded. Data were obtained from the electronic medical record system and analyzed using SPSS software (IBM Corp, Armonk, NY). Patients with preintervention duplex ultrasound-confirmed steal were identified and further evaluated by access type (AVG or AVF). The primary end point was clinical symptom resolution. There were 257 patients who underwent surgical interventions for steal syndrome. Of these, 143 patients had a preoperative duplex ultrasound examination suggestive of steal syndrome, with 98 associated with AVF (68.5%) and 45 associated with AVG (31.5%). Our population included predominantly women (65.7%) and African Americans (53.8%), with a mean age of 63.2 years (23-90 years). Symptom resolution for the two groups is reported in the Fig. In the AVF group, there was a statistically significant difference for complete symptom resolution between DRIL, PAI, banding, and access ligation at 64.6%, 80%, 26.3%, and 100%, respectively (χ2 test, P = .001). For AVGs, there was no statistically significant difference in symptom resolution between different surgical modalities (χ2 test; P = .555). In patients with AVF-associated steal, efficacy of DRIL and PAI in symptom resolution was superior to banding with statistical significance. Whereas access ligation had a higher percentage of symptom resolution in this subset, it should be reserved for cases of severe disease or when other viable options are absent. For AVG, clinical judgment and symptoms should be used in guiding surgical treatment preferences for symptom resolution.

A pilot study comparing bovine mesenteric artery and expanded polytetrafluoroethylene grafts as non-autogenous hemodialysis options.

Background Many dialysis patients do not have the necessary conditions for construction of a native arteriovenous fistula (AVF). Expanded Polytetrafluoroethylene (ePTFE) vascular prostheses are the most widely-used option, but it is known that they are inferior to native vein AVFs. Objectives To identify a graft with superior performance to ePTFE, comparing their results with those of AVFs made from bovine mesenteric arteries treated with L-Hydro technology (Labcor Laboratories ®). Methods A prospective and controlled study of 10 patients with AVFs constructed with ePTFE and 10 patients with L-Hydro bioprostheses, matched for comorbidities. The variables studied were: primary patency, assisted primary patency, and secondary patency, surgical manipulability, and prevalence of infections. The performance of prostheses was assessed by duplex-scan and repeated consultations with health professionals at hemodialysis clinics. The chi-square test was used for statistical analysis. Results After 1 year of postoperative follow-up, secondary and primary patency rates were higher for L-Hydro than ePTFE AVFs. Fewer interventions were needed to maintain AVF patency in the L-Hydro AVF group. The most common complication was graft thrombosis, which was more frequent in the ePTFE group. While the figures indicate more favorable outcomes in the L-Hydro AVFs, this could not be confirmed with the statistical treatment employed. Conclusions The L-Hydro graft appears to be a valuable alternative option for AVFs, since it seems to require fewer interventions to maintain patency when compared to ePTFE grafts.

The Clinical and Economic Effect of Vascular Access Selection in Patients Initiating Hemodialysis with a Catheter.

Patients in the United States frequently initiate hemodialysis with a central venous catheter (CVC) and subsequently undergo placement of a new arteriovenous fistula (AVF) or arteriovenous graft (AVG). Little is known about the clinical and economic effects of initial vascular access choice. We identified 479 patients starting hemodialysis with a CVC at a large medical center (during 2004-2012) who subsequently had an AVF (n=295) or AVG (n=105) placed or no arteriovenous access (CVC group, n=71). Compared with patients receiving an AVG, those receiving an AVF had more frequent surgical access procedures per year (1.01 [95% confidence interval, 0.95 to 1.08] versus 0.62 [95% confidence interval, 0.55 to 0.70]; P<0.001) but a similar frequency of percutaneous access procedures per year. Patients receiving an AVF had a higher median annual cost (interquartile range) of surgical access procedures than those receiving an AVG ($4857 [$2523-$8835] versus $2819 [$1411-$4274]; P<0.001), whereas the annual cost of percutaneous access procedures was similar in both groups. The AVF group had a higher median overall annual access-related cost than the AVG group ($10,642 [$5406-$19,878] versus $6810 [$3718-$13,651]; P=0.001) after controlling for patient age, sex, race, and diabetes. The CVC group had the highest median annual overall access-related cost ($28,709 [$11,793-$66,917]; P<0.001), largely attributable to the high frequency of hospitalizations due to catheter-related bacteremia. In conclusion, among patients initiating hemodialysis with a CVC, the annual cost of access-related procedures and complications is higher in patients who initially receive an AVF versus an AVG.

Comparison of Complications of Arteriovenous Fistula with Permanent Catheter in Hemodialysis Patients: A Six-month Follow-up.

Background:Arteriovenous fistula (AVF), permanent catheter (PC), and vascular graft are three vascular access types used for hemodialysis procedure. Due to insufficient reliable information on the comparison between AVF and PC, this study was conducted to compare AVF and PC regarding dialysis adequacy.Materials and Methods:This prospective study was carried out from March, 2013 to September, 2013. In this study, 76 hemodialysis patients were enrolled and assigned to two unequal groups of AVF and PC. Before and after the dialysis session, blood samples were taken for laboratory examinations and measurement of urea reduction ratio (URR) and Kt/V. The patients were followed up for six months, and then laboratory examinations were repeated.Results:Of the 76 hemodialysis patients, 30 had AVF and others PC. During the 6-month follow-up, 24 patients in PC group but only one patient in AVF group showed infection (P = 0.006), while in each group, three cases of thrombosis were seen (P = 0.58); however, catheter dysfunction was seen in 13 patients of PC group but no patients of AVF group (P = 0.004). There was no difference between the two groups in Kt/V and URR at the beginning of the study; however, after six months, Kt/V and URR were greater in AVF group (P < 0.05).Conclusions:In addition to some advantages of AVF over PC, such as lower rate of infection and thrombosis, we also found better dialysis adequacy in AVF group. We recommend that AVF be created in all of patients with chronic kidney disease who are candidates for hemodialysis.