Longitudinal micro-incision creation prior to balloon angioplasty for treatment of arteriovenous access dysfunction in a real-world patient population: 6-month cohort analysis.

INTRODUCTION: Routine hemodialysis depends on well-functioning vascular access. In the event of vascular access dysfunction, percutaneous transluminal balloon angioplasty (PTA) is conducted to restore patency. Although an angioplasty procedure can provide an excellent immediate result by opening the access to allow dialysis to continue, the long-term patency rates are less than satisfactory. The goal of this study was to assess the outcomes of patients who underwent a novel vessel preparation via longitudinal, controlled-depth micro-incisions prior to PTA. METHODS: This multicenter, prospective, observational registry enrolled hemodialysis patients scheduled to undergo PTA of their arteriovenous fistula or graft due to clinical or hemodynamic abnormalities. A primary endpoint was anatomic success, defined as angiographic confirmation of <30% residual stenosis post-procedure without an adverse event. Additional assessments included device technical success, clinical success, freedom from target lesion revascularization, target lesion primary patency, and circuit primary patency at 6 months. FINDINGS: A total of 148 lesions were treated with the FLEX Vessel Prep™ System (FLEX VP) prior to PTA in 114 subjects at eight clinical sites. Target lesions were 21 ± 25 mm in length with mean pre-procedure stenosis of 75.2% ± 4.7%. Five procedural complications were recorded without serious adverse events. Two subjects did not complete the follow-up evaluation. Target lesion primary patency across all subjects at 6-months was 62.2% with mean freedom from target lesion revascularization of 202.7 days. Target lesion primary patency and freedom from target lesion revascularization for AVF cases (n = 72) were 67.5% and 212.9 days, respectively. Target lesion primary patency and freedom from target lesion revascularization for AVGs (n = 42) were 52.4% and 183.3 days, respectively. In cases treating AVF cephalic arch stenosis (n = 25), 6-month target lesion primary patency was 70.6% and freedom from target lesion revascularization was 213.4 days. DISCUSSION: This FLEX-AV registry demonstrates safety and effectiveness, notably in the cephalic arch and AVGs, when FLEX VP is used prior to PTA for treatment of vascular access dysfunction in a population of end-stage renal disease subjects.

Long-Term Results from the Pivotal Multicenter Trial of Ultrasound-Guided Percutaneous Arteriovenous Fistula Creation for Hemodialysis Access.

PURPOSE: To report the 5-year results from the Pivotal Multicenter Trial of Ultrasound-Guided Percutaneous Arteriovenous Fistula (pAVF) Creation for Hemodialysis Access. MATERIALS AND METHODS: The retrospective review of 107 intent-to-treat (ITT) patients from the pivotal trial provided a long-term follow-up population (LTP) of 85 patients with a median follow-up duration of 50 months (range, 12-60 months). Data evaluated in the LTP group were fistula maturation and usage, secondary procedures, and complications. The Kaplan-Meier analysis of primary patency, assisted primary patency, cumulative patency, and functional patency (time from 2-needle cannulation to abandonment) were performed for the ITT population. RESULTS: In the LTP, 99% (84 of 85) of fistulae were mature, with 99% (78 of 79) of patients requiring hemodialysis using their pAVF. Sustained fistula use (2-needle cannulation at the prescribed rate, 2 of 3 sessions) was achieved in 92% (78 of 85) of patients, with 7 patients not using their pAVF because they were not on dialysis (n = 4), were on peritoneal dialysis (n = 2), and refused to use fistula (n = 1). Fistula maintenance was required in 31.8% (27 of 85) of patients and included fistula dysfunction (21.2%), thrombosis (5.9%), cannulation injury (12.9%), and arm swelling (4.7%). The number of procedures performed per patient per year to maintain function and patency was 0.32 (91 of 288) for years 2-5. The cumulative patency rates were 89.5%, 88.4%, 88.4%, 85.6%, and 82.0% for years 1, 2, 3, 4, and 5, respectively. The functional patency was 91.8% at the end of the study. There were no major complications related to pAVF during the long-term follow-up. CONCLUSIONS: Percutaneous fistulae have provided clinically effective and durable access for hemodialysis with low complications. The continued use and evaluation of pAVF are warranted.

Patient selection, education, and cannulation of percutaneous arteriovenous fistulae: An ASDIN White Paper.

End-stage kidney disease patients who are candidates for surgical arteriovenous fistula creation commonly experience obstacles to a functional surgical arteriovenous fistula, including protracted wait time for creation, poor maturation, and surgical arteriovenous fistula dysfunction that can result in significant patient morbidity. The recent approval of two endovascular devices designed to create a percutaneous arteriovenous fistula enables arteriovenous fistula creation to be placed in the hands of interventionalists, thereby increasing the number of arteriovenous fistula providers, reducing wait times, and allowing the patient to avoid surgery. Moreover, current studies demonstrate that patients with percutaneous arteriovenous fistula experience improved time to arteriovenous fistula maturation. Yet, in order to realize the potential advantages of percutaneous arteriovenous fistula creation within our hemodialysis patient population, it is critical to select appropriate patients, ensure adequate patient and dialysis unit education, and provide sufficient instruction in percutaneous arteriovenous fistula cannulation and monitoring. In this White Paper by the American Society of Diagnostic and Interventional Nephrology, experts in interventional nephrology, surgery, and interventional radiology convened and provide recommendations on the aforementioned elements that are fundamental to a functional percutaneous arteriovenous fistula.

The Pivotal Multicenter Trial of Ultrasound-Guided Percutaneous Arteriovenous Fistula Creation for Hemodialysis Access.

PURPOSE: To evaluate safety and efficacy of arteriovenous fistulas (AVFs) created with a thermal resistance anastomosis device. MATERIALS AND METHODS: A prospective single-arm trial at 5 sites enrolled 107 patients. Patients underwent ultrasound (US)-guided anastomosis creation between the proximal radial artery and perforating vein with the Ellipsys Vascular Access System (Avenu Medical, Inc, San Juan Capistrano, California) followed by separate maturation procedures. Primary endpoints were brachial artery flow volume ≥ 500 mL/min and target vein diameter ≥ 4 mm in > 49% of patients and absence of device-related complications at 90 days. RESULTS: AVFs with fused anastomoses were created in 95% (102/107) of patients. Maturation procedures included anastomotic balloon dilation in 72% (77/107), brachial vein embolization in 32% (34/107), cubital vein ligation in 31% (33/107), and surgical transposition in 26% (28/107) of patients. Primary flow and diameter endpoints were achieved in 86.0% (92/107) of patients, exceeding performance goal of 49% (P < .0001). No major adverse events were attributed to the device. Cumulative patency was 91.6%, 89.3%, and 86.7% at 90 days, 180 days, and 360 days. Target dialysis veins were cephalic, basilic, and brachial veins in 74% (73/99), 24% (24/99), and 2% (2/99) of patients. Two-needle dialysis was achieved in 88% (71/81) of patients on hemodialysis at a mean 114.3 days ± 66.2. Functional patency was 98.4%, 98.4%, and 92.3% at 90 days, 180 days, and 360 days. CONCLUSIONS: The Ellipsys® Vascular Access System met primary safety and efficacy endpoint goals in the US pivotal trial.

Thermal Resistance Anastomosis Device for the Percutaneous Creation of Arteriovenous Fistulae for Hemodialysis.

PURPOSE: To evaluate the safety and efficacy of arteriovenous fistula (AVF) creation with a thermal resistance anastomosis device (TRAD). MATERIALS AND METHODS: From January 2014 to March 2015, 26 patients underwent ultrasound (US)-guided percutaneous creation of proximal radial artery-to-perforating vein AVFs with a TRAD that uses heat and pressure to create a fused anastomosis. Primary endpoints were fistula creation, patent fistula by Doppler US, two-needle dialysis at the prescribed rate, and device-related complications. RESULTS: Technical success rate of fistula creation was 88% (23 of 26). Procedure time averaged 18.4 minutes (range, 5-34 min), and 96% of anastomoses (22 of 23) were fused. At 6 weeks, 87% of AVFs (20 of 23) were patent, 61% (14 of 23) had 400-mL/min brachial artery flow, 1 patient was receiving dialysis, 2 fistulae had thrombosed, and 1 patient had died unrelated to the procedure. Eighty percent (16 of 20), 70% (14 of 20), and 60% (12 of 20) of patients were receiving dialysis at 3, 6, and 12 months; 4 patients died, 3 fistulae failed, and one patient was lost to follow-up. Overall, 87% of AVFs (20 of 23) had an additional procedure at a mean of 56 days (range, 0-239 d), including balloon dilation in 43% (n = 10), brachial vein embolization in 26% (n = 6), basilic vein ligation in 17% (n = 4), venous transposition in 30% (n = 7), and valvulotomy in 4% (n = 1). There were no major complications related to the device. CONCLUSIONS: Percutaneous AVFs created with a TRAD met the safety endpoints of this study. Midterm follow-up demonstrated intact anastomoses and fistulae suitable for dialysis.

Percutaneous valvulotomy as an alternative to transposition of a brachiocephalic fistula.

Transposition of a deep (9-12 mm) autogenous brachiocephalic vein fistula was required for adequate hemodialysis access in a morbidly obese patient. The patient was a poor candidate for surgical transposition of the upper-arm cephalic vein. As an alternative, retrograde fistula flow was established percutaneously through a 6-F sheath in the forearm cephalic vein with the over-the-wire LeMaitre valvulotome. The retrograde flow in the forearm added 7 cm of superficial vein 6.2-9 mm in diameter with a flow rate of 940-2,868 mL/min, eliminating the need for surgical transposition. The percutaneous technique and required anatomy are described.

Computational fluid dynamic evaluation of the side-to-side anastomosis for arteriovenous fistula.

OBJECTIVE: The goal of this research was to compare side-to-side (STS) and end-to-side (ETS) anastomoses in a computer model of the arteriovenous fistula with computational fluid dynamic analysis. METHODS: A matrix of 17 computer arteriovenous fistula models (SolidWorks, Dassault Systèmes, France) of artery-vein pairs (3-mm-diameter artery + 3-mm-diameter vein and 4-mm-diameter artery +6-mm-diameter vein elliptical anastomoses) in STS, 45° ETS, and 90° ETS configurations with cross-sectional areas (CSAs) of 3.5 to 18.8 mm(2) were evaluated with computational fluid dynamic software (STAR-CCM+; CD-adapco, Melville, NY) in simulations at defined flow rates from 600 to 1200 mL/min and mean arterial pressures of 50 to 140 mm Hg. Models and configurations were evaluated for pressure drop across the anastomosis, arterial inflow, venous outflow, arterial outflow, velocity vector, and wall shear stress (WSS) profile. RESULTS: Pressure drop across the anastomosis was inversely proportional to anastomotic CSA and to venous outflow and was proportional to arterial inflow. Pressure drop was greater in 3 + 3 models than in 4 + 6 STS models; 90° ETS configurations had the lowest pressure drops and were nearly identical, whereas 45° ETS configurations had the highest pressure drops. Venous outflow in the 4 + 6 model in STS configurations, evaluated at 100 mm Hg arterial inflow pressure, was 390, 592, 610, and 886 mL/min in anastomotic CSAs of 3.5, 5.3, 7.1, and 18.8 mm(2), respectively, and was similar in 90° ETS (609 and 908 mL/min) and lower in 45° ETS (534 and 562 mL/min) configurations at CSAs of 5.3 and 18.8 mm(2). The mean increase in venous outflow was 69 mL/min (range, -59 to 134) between 3 + 3 and 4 + 6 models at 100 mm Hg arterial inflow. The most uniform WSS profile occurs in STS anastomoses followed by 45° ETS and then 90° ETS anastomoses. CONCLUSIONS: The STS and 90° ETS anastomoses have high venous outflow and a tendency toward reversed arterial outflow. The 45° ETS anastomosis has reduced venous outflow but resists reversed arterial outflow. The STS anastomosis has more uniform WSS characteristics compared with the 45° and 90° ETS anastomoses.

Mapping of the snuffbox and cubital vessels for percutaneous arterial venous fistula (pAVF) in dialysis patients.

PURPOSE: Report on the anatomic qualification of the snuffbox radial artery (SBRA) and proximal radial artery (PRA) for pAVF.
 METHODS: Retrospective analysis of upper extremity mapping in 64 limbs in 55 dialysis patients was performed. The radial artery was assessed for diameter, patency, flow and proximity to the adjacent vein to SBRA and PRA. Sites qualified for pAVF on a binary basis when the in situ radial artery and adjacent vein were straight, parallel, greater than 2 mm in diameter and within 1.5 mm of each other. Effect of age, sex, diabetes, systolic blood pressure and obesity were assessed with logistic regression. Mean, median and frequency distribution of vessel diameter and distance were analyzed.
 RESULTS: Radial artery sites were qualified for pAVF in 47.6% (30/63) at the SBRA and 87.9% (29/33) at the PRA. SBRA sites were disqualified for vessel size in 36.4% (12/33 overall, usually vein 11/12), distance in 24% (8/33) and both 36.4% (12/33). All (4/4) PRA sites were disqualified for vessel size alone. The adjacent vein was the median vein or cephalic vein for the SBRA, and the perforating vein or vena comitans for the PRA. Effects of age, sex, diabetes, systolic blood pressure, obesity and prior fistula did not attain statistical significance.
 CONCLUSIONS: Most dialysis patients meet the anatomic requirements for pAVF in the SBRA or PRA. Vessel size is the most common limiting variable followed by distance between vessels.

Bard Recovery filter: evaluation and management of vena cava limb perforation, fracture, and migration.

PURPOSE: To report on the evaluation and management of Bard Recovery filter limb perforation, fracture, and migration. MATERIALS AND METHODS: In 2007, all patients who received a Bard Recovery filter at a single institution were contacted for consultation and evaluation by noncontrast computed tomography. Rates of limb perforation, fracture, and migration were evaluated on early (<180 days) and final images. Retrieval success and complications were evaluated. RESULTS: Fourteen of 16 patients with Bard Recovery filters were evaluated. The early images in nine patients (mean, 30 days; range, 0-126 d +/- 40) demonstrated arm perforations in 56% (n = 5), leg perforation in 11% (n = 1), and no early fractures or migrations. Final images (mean, 899 days; range, 119-1,218 d +/- 320) demonstrated filter arm perforations in all 14 patients. Leg perforations were seen in 36% of patients (n = 5), and there were a total of four fractures with migration in 21% of patients (n = 3). All fractures occurred in arms that had perforated the vena cava on early images. Two patients had already had their filters retrieved at 119 and 302 days, respectively; the remaining 12 patients elected to have their filters retrieved after evaluation. All 12 filters were retrieved at a mean of 1,021 days (range, 119-1,242 d +/- 134). Leg hook fractures occurred during eight of 12 filter retrieval procedures (67%). CONCLUSIONS: Recovery filter limb perforation of the vena cava increases over time and is associated with a 21% incidence of filter arm fracture and migration. Follow-up imaging is recommended. Filter retrieval has a high success rate and is the authors' preferred management strategy.

Retrieval of the recovery filter after arm perforation, fracture, and migration to the right ventricle.

The authors report a case of inferior vena cava filter arm perforation, followed by fracture and migration to the right ventricle causing chest pain and nonsustained ventricular tachycardia. Review of abdominal computed tomographic (CT) scans show the two filter arms that fractured and migrated had perforated the vena cava 2 years previously. Microscopic evaluation of the retrieved filter and limbs revealed bending metal fatigue at the fracture sites. This case and review of the literature suggest a causal relation between Bard Recovery filter arm perforation and subsequent fracture and migration. Percutaneous retrieval of filters with arm fracture or arm migration is recommended.