A Single-Center Experience with Forearm Arteriovenous Loop Grafts for Hemodialysis.

Autogenous arteriovenous fistula (AVF) remains the standard of hemodialysis (HD) access; however, it cannot be reasonably obtained in all patients. For patients with contraindications to AVFs, prosthetic arteriovenous graft (AVG) remains an alternative. AVGs are plagued by high failure rates; however, there is a paucity of literature examining this. This study aims to examine a single-center review of outcomes of forearm loop AVGs in patients requiring HD access. A single institution, retrospective chart review was completed from 2012 to 2019, including demographics, end-stage renal disease etiology, brachial vessel diameters, and comorbidities. Logistic regression and Cox proportional hazard models were evaluated. Outcomes were defined as primary patency (time elapsed from graft creation until it was utilized as the patient's primary access), primary-assisted patency (time from primary access to intervention to maintain patency), and functional patency (time from graft placement until graft failure). Additionally, multinomial regression models were used to evaluate associations with categorical number of required interventions. Ninety-eight patients [mean age 61.8 (13.9) years, 42.9% female] were identified as having brachial artery to brachial vein AVG creation during the study period, of which 75% achieved primary patency. Primary-assisted patency was 0.36 [standard error (SE) 0.07] at 6 months and 0.12 (SE 0.05) at 1 year. Functional patency was 0.75 (SE 0.07) at 6 months and 0.43 (SE 0.09) at 1 year. No association between preoperative vessel diameters and primary-assisted or functional patency was observed. Interestingly, there was a significant negative association between previous ipsilateral access and achievement of primary patency with a 60% decrease in odds of achieving primary patency in patients with previous ipsilateral access [odds ratio 0.4, 95% confidence interval (CI) 0.1-0.9, P = 0.03]. There was also noted to be a significant association between the presence of an ipsilateral catheter and increased risk of subsequent abandonment of the AVG (hazard ratio 2.6, 95% CI 1.1-5.8, P = 0.02). Prosthetic forearm loop AVGs remain hindered in their utility as they show high rates of graft failure within a year of creation. A significant patient-specific factor leading to this was not clearly demonstrated. As guidelines change regarding the nature of dialysis access for patients on HD, these results draw into question the utility of prosthetic forearm loop grafts in patients requiring long-term HD access.

Brastauskas IM ，Patel N ，German Z ，Davis RP ，Stafford JM ，Edwards M ，Murea M ，Goldman MP ... -  《-》

The forearm arteriovenous graft between the brachial artery and the brachial vein as a reliable dialysis vascular access for patients with inadequate superficial veins.

The arteriovenous fistula (AVF) is recommended as the preferred hemodialysis access. However, placing an AVF in all patients may result in poor access outcomes and increased central venous catheter (CVC) use because of increased comorbid conditions, age, and suboptimal vessels. In patients with inadequate superficial veins for AVFs, the use of the brachial veins for creation of forearm arteriovenous grafts (AVGs) has received limited attention. This retrospective study aimed to evaluate outcomes of forearm brachial-brachial AVGs (BB-AVGs) placed in patients with poor superficial veins. We identified 111 BB-AVGs created in 111 consecutive patients, using standard-walled polytetrafluoroethylene grafts, between January 2010 and December 2015. After excluding 6 patients (non-dialysis initiation, missing information, and death within 1 month), we included 105 patients from 21 dialysis centers. We analyzed primary failures, time to cannulation, patency, complications, and revisions. Patency rates were calculated by the Kaplan-Meier method. The incidence of complications and revisions was expressed as number of events per person-year. A total of 105 patients (median age, 69 years) were followed up for a median time of 21.2 months (interquartile range, 9.2-36.5 months). Of the patients, 72.4% were on chronic hemodialysis and had previously undergone one or more access procedures. At the time of BB-AVG placement, prior accesses were 39 AVFs, 20 tunneled CVCs, and 17 AVGs. BB-AVG rates of primary failure and revision before cannulation were 7.6% and 5.7%, respectively. BB-AVGs were cannulated after a median time of 3.4 weeks (interquartile range, 2.8-4.1 weeks). Primary patency rates at 12, 24, and 36 months were 49.5%, 29.5%, and 19.5%. Secondary patency rates at 12, 24, and 36 months were 76.3%, 62.7%, and 54.6%. After cannulation, the incidence of complications and revisions was 1.054 and 0.649 per person-year, respectively. Most complications and interventions were due to thrombosis (0.527 per person-year) or stenosis (0.381 per person-year) and related interventions (0.490 per person-year). A minority of patients experienced AVG infections (0.052 per person-year), with only two requiring access removal. In patients with poor superficial veins, the forearm BB-AVG is a reliable access because of low access-related morbidity and considerable long-term access survival. BB-AVG placement has the advantage of preserving proximal vessels. In these patients, such an approach can delay both rapid exhaustion of vascular sites and early recourse to CVC permanent use.

Fumagalli G ，Trovato F ，Migliori M ，Panichi V ，De Pietro S ... -  《-》

The effect of location and configuration on forearm and upper arm hemodialysis arteriovenous grafts.

The arteriovenous graft (AVG) is most often used in hemodialysis patients when an autogenous fistula is not feasible. The optimal location (forearm or upper arm) and configuration (loop or straight) of AVGs are not known. To evaluate relationships of AVG location and configuration with patency, we conducted a secondary analysis using data from a randomized, placebo-controlled trial of dipyridamole plus aspirin for newly placed AVG. Participants of the Dialysis Access Consortium (DAC) Graft Study with newly placed upper extremity prosthetic grafts involving the brachial artery were studied. Multivariable analyses adjusting for trial treatment group, center, gender, race, body mass index, diabetes, current treatment with chronic dialysis, and prior arteriovenous vascular access or central venous catheter were performed to compare outcomes of forearm (fAVG) and upper arm (uAVG) grafts, including loss of primary unassisted patency (LPUP) and cumulative primary graft failure (CGF). Subgroup analyses of graft configuration and outflow vein used were also conducted. A total of 508 of the 649 participants (78%) enrolled in the trial had an upper extremity brachial artery graft placed, 255 with fAVG and 253 with uAVG. Participants with fAVG were less often male (33% vs 43%; P = .03), African American (62% vs 78%; P < .001), and receiving dialysis at the time of surgery (62% vs 80%; P < .001). Participants with fAVG had a higher mean body mass index (33 vs 29; P < .001). The LPUP (fAVG 70% vs uAVG 78%; P = .07) and CGF (33% vs 36%; P = .91) were similar between fAVG and uAVG at 1-year follow-up. In multivariable analysis, AVG location (uAVG vs fAVG) was not associated with LPUP (hazard ratio, 1.21; 95% confidence interval, 0.90-1.63; P = .20) or CGF (hazard ratio, 1.36; 95% confidence interval, 0.94-1.97; P = .10). LPUP did not differ significantly between fAVG and uAVG among subgroups based on AVG configuration (P = 1.00) or outflow vein used (P = .16). Patency was comparable between fAVG and uAVG despite the larger caliber veins often encountered in the upper arm in carefully selected patients. Our findings support the traditional view that, in order to preserve a maximal number of access sites, the forearm location should be considered first before resorting to an upper arm graft.

Farber A ，Tan TW ，Hu B ，Dember LM ，Beck GJ ，Dixon BS ，Kusek JW ，Feldman HI ，Dialysis Access Consortium (DAC) Study Group ，Dialysis Access Consortium DAC Study Group ... -  《-》

A comparison of brachial artery-brachial vein arteriovenous fistulas with arteriovenous grafts in patients with poor superficial venous anatomy.

The autogenous arteriovenous fistula (AVF) has been shown to be superior to the arteriovenous graft (AVG) with respect to cost, complications, and primary patency. Therefore, the National Kidney Foundation Disease Outcomes Quality Initiative guidelines recommend reserving AVGs for patients who do not have adequate superficial venous anatomy to support AVF placement. The brachial artery-brachial vein arteriovenous fistula (BVAVF) has emerged as an autologous last-effort alternative. However, there are limited data comparing BVAVFs and AVGs in patients who are otherwise not candidates for a traditional AVF. Patients who received a BVAVF from July 2009 to July 2014 were compared with those who received an AVG during the same period. At our institution, BVAVF and AVG are only performed in patients with poor superficial venous anatomy. Patient demographic data, operative details, and subsequent follow-up were collected. BVAVFs were performed with a two-stage approach, with initial arteriovenous anastomosis, followed by delayed superficialization or transposition. Our primary outcome measure was primary functional assisted patency at 1 year. Patients lost to follow-up were excluded. A subgroup analysis was also performed for patients in whom the BVAVF or the AVG was their first hemodialysis access surgery. During the study period, 29 patients underwent BVAVF and 32 underwent AVG. There were no differences in age, gender, or presence of diabetes between the two groups. The median days to cannulation from the initial operation were 141 (interquartile range, 94-214) in the BVAVF group and 29 (interquartile range, 14-33) in the AVG group (P < .001). Fewer patients required interventions to maintain or re-establish patency in the BVAVF group than in the AVG group (10% v. 44%; P < .01). The 1-year primary patency was greater for BVAVF (62% vs 25%; P < .01); however, there was no difference in the functional assisted primary patency rates at 1 year (45% vs 25%; P = .1). Subgroup analysis demonstrated greater 1-year primary functional assisted primary patency (52% vs 19%; P < .05) in patients without prior access surgery. The BVAVF is a viable alternative to the AVG in patients with inadequate superficial venous anatomy, especially in access-naïve patients. The decision to perform BVAVF must be weighed against the delay in functional maturation expected compared with AVG.

Pham XD ，Kim JJ ，Ihenachor EJ ，Parrish AB ，Bleck JD ，Kaji AH ，Koopmann MC ，de Virgilio C ... -  《-》

Results of repeated percutaneous interventions on failing arteriovenous fistulas and grafts and factors affecting outcomes.

Repeated percutaneous interventions on failing arteriovenous fistulas (AVFs) and arteriovenous grafts (AVGs) for hemodialysis are common, but the outcomes are largely unknown. We sought to determine the results of the second percutaneous intervention on failing AVGs and AVFs and to identify factors associated with loss of patency. For the purpose of this study, the second percutaneous intervention was identified as the index procedure. We reviewed the second percutaneous interventions on failing AVFs and AVGs at a single institution between 2007 and 2013. Patient comorbidities, graft or fistula configuration, lesion characteristics, and procedural characteristics of the intervention performed were analyzed with respect to technical success, primary patency, primary assisted patency, and secondary patency. Patency was defined per Society for Vascular Surgery recommended reporting standards and was determined from the time of the index procedure. Cox proportional hazards multivariable modeling was performed to identify independent determinants of loss of patency. Among 91 patients, 96 second-time percutaneous interventions were performed on 52 AVFs and 44 AVGs. Patients included 56% men and 44% women with a mean age of 64 ± 17 years. The lesions intervened on were primarily located along the accessed portion of the outflow in AVFs and within the length of the graft and at the venous anastomosis in AVGs. Transluminal angioplasty alone was performed in 82 procedures (85%), and uncovered or covered stents were placed in 15 procedures (16%). Pharmacomechanical thrombectomy was performed in 32 patients (34%) and was more commonly performed in AVGs compared with AVFs (53% vs 17%; P = .0002). Technical success was achieved in 90 procedures (97%; n = 92). One-year primary patency, assisted primary patency, and secondary patency rates were 35%, 86%, and 86%, respectively. One-year primary patency did not differ between AVFs and AVGs, but secondary patency was lower for AVG in comparison to AVF (P = .04). On multivariable analysis, only the need for pharmacomechanical thrombectomy significantly predicted failure of primary patency (hazard ratio, 2.6; 95% confidence interval, 1.6-4.3). The presence of an AVG rather than an AVF independently predicted failure of secondary patency (hazard ratio, 2.9; 95% confidence interval, 1.0-8.2). The second percutaneous interventions on AVFs and AVGs are associated with excellent technical success but poor primary patency. The need for pharmacomechanical thrombectomy predicts the need for additional percutaneous intervention to maintain patency. With additional interventions, acceptable secondary patency out to 5 years can be achieved, although AVGs have inferior secondary patency to AVFs. To develop optimal practice management algorithms, the effectiveness of repeated percutaneous interventions for failing AVGs and AVFs vs creation of a new access should be further investigated.

Malka KT ，Flahive J ，Csizinscky A ，Aiello F ，Simons JP ，Schanzer A ，Messina LM ，Robinson WP ... -  《-》