Creating hemodialysis autogenous access in children and adolescents.

OBJECTIVE: End-stage renal disease (ESRD) in childhood and adolescence is rare, with relatively few published reports of pediatric ESRD vascular access. This study analyzes a 10-year experience creating arteriovenous fistulas (AVFs) in children and adolescents. Our goal is to review our strategy for creating functional autogenous vascular access in younger patients and report our results. METHODS: We retrospectively reviewed data and outcomes for consecutive vascular access patients aged ≤19 years during a 10-year period. Each patient had preoperative vascular ultrasound mapping by the operating surgeon in addition to physical examination. A distal forearm radiocephalic AVF was the first access choice when feasible, and a proximal radial artery inflow AVF was the next option. Demographic data, inflow artery, venous outflow target, and required transposition vs direct AVFs were variables included in the analysis. Primary and cumulative patency were calculated by Kaplan-Meier analysis. RESULTS: Thirty-seven AVFs were created in 35 patients. No grafts were used. Ages were 6 to 19 years (mean, 15 years), and 20 were male. Causes of ESRD included glomerular disease (n = 18) and urinary obstruction or reflux (n = 7), among others. Three had previous AVFs, and 10 were obese. The proximal radial artery supplied AVF inflow in 25 patients and the brachial artery in only seven. Eleven individuals required a transposition and one a vein translocation to the contralateral arm. No patients developed hand ischemia, although two later required banding procedures for high flow. Eleven patients had successful transplants. A single patient died, unrelated to the vascular access. Five AVFs failed. Of these, two had new successful AVFs created, two regained renal function, one was transplanted, and one declined other procedures. Primary and cumulative patency rates were 75% and 85% at 12 months, 70% and 85% at 24 months, and 51% and 85% at 36 months, respectively. Median follow-up was 16 months. CONCLUSIONS: Creating an AVF for hemodialysis is a successful vascular access strategy for pediatric and adolescent patients. Proximal radial artery AVFs provided safe and functional access when a distal AVF was not feasible. Cumulative AVF patency was 85% at 36 months.

Customizable modification of banding with external stenting for arteriovenous fistula flow reduction.

We performed a single-center retrospective study of prospectively collected data for all patients who had flow reduction surgery with FRAME FR between November 2020 and January 2021. Ten patients had arteriovenous fistula flow reduction surgery with this technique. One patient had a distal fistula, whereas nine were within the cubital fossa. In nine patients the device was applied over the postanastomotic arteriovenous fistula outflow vein and in one in the preanastomotic radial artery. Technical success was achieved in all patients with a median flow reduction from 2150 to 825 mL/min. There were no wound or device-specific complications.

Percutaneous arteriovenous fistula creation.

The first percutaneous systems used to create an arteriovenous fistula for hemodialysis were approved by the US Food and Drug Administration in 2018 and included the Ellipsys and WavelinQ devices. Early results and longer-term studies of these catheter-based devices suggest that they offer important benefits and potentially improved outcomes in patients with appropriate anatomy. The deep communicating vein in the cubital fossa and its relationship to the proximal radial artery or proximal ulnar artery are key vascular elements of both systems. The devices differ significantly in technical design, energy source, imaging requirements, procedure times, catheters, access vessel sites, and techniques. We review the two approved percutaneous arteriovenous fistula devices, including technical considerations, selecting the appropriate patient, postoperative evaluation, interventions, outcomes, potential complications, and cannulation issues.

Synthetic Control of Mitochondrial Dynamics: Developing Three-Coordinate Au(I) Probes for Perturbation of Mitochondria Structure and Function.

Mitochondrial structure and organization is integral to maintaining mitochondrial homeostasis and an emerging biological target in aging, inflammation, neurodegeneration, and cancer. The study of mitochondrial structure and its functional implications remains challenging in part because of the lack of available tools for direct engagement, particularly in a disease setting. Here, we report a gold-based approach to perturb mitochondrial structure in cancer cells. Specifically, the design and synthesis of a series of tricoordinate Au(I) complexes with systematic modifications to group 15 nonmetallic ligands establish structure-activity relationships (SAR) to identify physiologically relevant tools for mitochondrial perturbation. The optimized compound, AuTri-9 selectively disrupts breast cancer mitochondrial structure rapidly as observed by transmission electron microscopy with attendant effects on fusion and fission proteins. This phenomenon triggers severe depolarization of the mitochondrial membrane in cancer cells. The high in vivo tolerability of AuTri-9 in mice demonstrates its preclinical utility. This work provides a basis for rational design of gold-based agents to control mitochondrial structure and dynamics.

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

RATIONALE & OBJECTIVE: 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. STUDY DESIGN: Retrospective study of prospectively collected clinical data. SETTING & PARTICIPANTS: All vascular access procedures conducted during a 34-month period were reviewed. The study groups comprised 89 percutaneous AVFs and 69 surgical AVFs. EXPOSURE: Percutaneous or surgical AVF placement. OUTCOME: AVF patency, function, and complications. ANALYTICAL APPROACH: 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. RESULTS: 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). LIMITATIONS: Retrospective study with a relatively short follow-up period, and not all patients required hemodialysis at the end of study. CONCLUSIONS: 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.

Comparison of surgical versus percutaneously created arteriovenous hemodialysis fistulas.

OBJECTIVE: The aim of the present study was to compare the results between percutaneous arteriovenous fistulas (p-AVFs) created with the Ellipsys device (Ellipsys Vascular Access System; Avenu Medical, San Juan Capistrano, Calif) and surgical arteriovenous fistulas (s-AVFs). METHODS: A single-center retrospective comparative study of the first 107 patients who had undergone p-AVF creation with the Ellipsys system from May 2017 to May 2018 with an equal number of consecutive patients who had undergone s-AVF creation in our center during the same period. The primary endpoints included the maturation and patency rates. The secondary endpoints were reintervention, risk of infection, and the incidence of steal syndrome and aneurysm formation. RESULTS: The demographic, hypertension, and diabetes data were similar for both groups. The only difference between the two groups was that more p-AVF patients had already been receiving hemodialysis (61% vs 47%; P < .05). The p-AVFs showed superior maturation rates at 6 weeks (65% vs 50%; P = .01). The primary patency rates were greater for the s-AVFs at 12 months (86% vs 61%; P < .01). However, primary patency was comparable between the two groups at 24 months (52% vs 55%; P = .48). No significant difference was found in the secondary patency rates at 12 (90% vs 91%) and 24 (88% vs 91%) months. At the 2-year follow-up point, the rate of percutaneous reintervention was similar; however, the s-AVFs had required more frequent surgical revision (36% vs 17%; P = .01). Issues with wound healing and infection were also more frequent with s-AVFs (9% vs 0.9%; P < .01). CONCLUSIONS: Fistulas created percutaneously with the Ellipsys system showed superior maturation rates and similar patency with s-AVFs created in an experienced high-volume vascular surgery practice. p-AVFs had a lower risk of wound healing issues, infection, and surgical revision. Larger, prospective, randomized multicenter studies are needed to confirm these findings.

Percutaneous creation of proximal radio-radial arteriovenous hemodialysis fistula before secondary brachial vein elevation.

OBJECTIVE: We evaluate the creation of a percutaneous proximal radial artery-radial vein arteriovenous fistula with Ellipsys® instead of the usual first-stage brachial artery fistula prior to a second-stage brachial vein elevation, in patients with inadequate cephalic and basilic veins. METHODS: Single center study of eight patients (six males, mean = 54 years) who underwent a two-stage brachial vein elevation procedure between May 2017 and October 2019. Inclusion criteria were life expectancy > 6 months, patent brachial and proximal radial artery (>2 mm in diameter) absent/inadequate cephalic and basilic veins, existence of a brachial vein >3 mm in diameter, and in continuity with a proximal radial vein > 2 mm in diameter. RESULTS: Technical success was 100%. Four patients required angioplasty of a juxta-anastomotic stenosis, accounting for a 6-month primary and secondary patency rates were 68% and 100%, respectively. Access flow averaged 982 mL/min (range 768-1586) at final follow-up evaluation. There were no significant adverse events related to the procedures. All fistulae were elevated at 4-12 (mean: 8) weeks post creation and were successfully cannulated with two needles after healing was completed (2-4 weeks after elevation). No patients developed hand ischemia or arm edema. CONCLUSIONS: Percutaneous creation of a proximal radial artery-radial vein fistula followed by brachial vein elevation is a safe and reliable option for autogenous access creation in patients with inadequate cephalic or basilic veins. Minimally invasive radial artery inflow and longer available length of the targeted brachial vein available for elevation are the main advantages in skilled hands.

Midterm results of percutaneous arteriovenous fistula creation with the Ellipsys Vascular Access System, technical recommendations, and an algorithm for maintenance.

OBJECTIVE: The aim of this study was to report our midterm results of percutaneous arteriovenous fistula (pAVF) creation using the Ellipsys (Avenu Medical, San Juan Capistrano, Calif) device and to present technical recommendations and our algorithm of pAVF maintenance. METHODS: A single-center comprehensive database of all consecutive predialysis and end-stage renal disease patients who had a pAVF creation with the Ellipsys device was reviewed retrospectively. Study end points included technical success, maturation, functional patency, and required interventions. RESULTS: Between May 2017 and July 2019, there were 234 patients (mean age, 64 years; 148 male [63%]) who had a pAVF created. Technical success was achieved in 232 individuals (99%), and average duration of the procedure was 15 minutes (7-35 minutes). Average follow-up was 252 days (range, 83-696 days). The 1-year primary, primary assisted, and secondary patency rates were 54%, 85%, and 96%, respectively. Average pAVF flow was 923 mL/min (range, 425-1440 mL/min). There were no significant adverse events related to the procedure. Only three patients (1%) required a later conversion of the pAVF anastomosis to a surgical fistula. Twenty-four (10%) patients required superficialization of deep outflow veins because of difficult cannulation. Average maturation time was 4 weeks (range, 1-12 weeks). Fourteen patients (6%) had early (<2 weeks after creation) cannulation of the pAVF. CONCLUSIONS: The Ellipsys pAVF device allows the rapid and safe creation of a reliable autogenous access. Rates of technical success, patency, and maturation were excellent. For patients unsuited for a distal radiocephalic arteriovenous fistula, it should be considered the next preferred access option.

ASDIN white paper: Assessment and management of hemodialysis access-induced distal ischemia by interventional nephrologists.

Although not common, hemodialysis access-induced distal ischemia is a serious condition resulting in significant hemodialysis patient morbidity. Patients with signs and symptoms suggestive of hand ischemia frequently present to the general and interventional nephrologist for evaluation. In order to care for these cases, it is necessary to understand this syndrome and its management. Most cases can be managed conservatively without intervention. Some cases requiring intervention may be treated using techniques within the scope of practice of the interventional nephrologists while other cases require vascular surgery. In order for the interventional nephrologists to evaluate and manage these cases in a timely and appropriate manner, practice guidelines are presented.

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.

Creating arteriovenous fistulas for children in Guatemala.

OBJECTIVE: The Guatemalan Foundation for Children with Kidney Diseases was established in 2003 as the first and only comprehensive pediatric nephrology program and hemodialysis unit in Guatemala. Bridge of Life (BOL) is a not-for-profit charitable organization focused on chronic kidney disease and supplied equipment, training and support during formation of the hemodialysis unit. Pediatric permanent vascular access (VA) expertise had not been established and noncuffed dialysis catheters provided almost all VA, many through subclavian vein access sites. BOL assistance was requested for establishing a VA surgical program, resulting in recurring BOL surgical missions to create arteriovenous fistulas (AVF) in these children. This study analyzes the BOL pediatric VA missions to Guatemala. METHODS: Three surgical pediatric VA missions were conducted in Guatemala from 2015 to 2017. Each mission was led by two or three surgeons. All supplies and equipment (including ultrasound units) were taken as part of each mission. The BOL surgical VA mission teams work with local pediatric surgeons, pediatric nephrologists, and dialysis nurses to establish collegial relationships and foster teaching interactions. We retrospectively reviewed the patient demographic data, procedures, and outcomes for these missions. RESULTS: AVFs were created in 54 new pediatric patients. Ages were 8 to 19 years (13.4 ± 2.8 years) and 29 patients (54%) were male. Patient weights were 28 to 50 kg (30.8 ± 8.3 kg) with body mass indexes of 12 to 25 kg/m2 (17.9 ± 2.9 kg/m2). Radiocephalic AVFs were created in 21 children (39%), proximal radial artery AVFs in 12 (22%). and brachial artery inflow AVFs in 5 (9%). Sixteen patients (30%) required transpositions and one a translocation; two of these were femoral procedures. Primary and cumulative patency rates were 83% and 85% at 12 months and 62% and 85% at 36 months, respectively. The median follow-up was 17 months. Interventions with fistulagram and balloon angioplasty options were not available for AVF dysfunction or access salvage during the study period. However, six patients underwent an AVF revision and salvage during subsequent missions or by one of the Guatemalan surgeons (R.S.). Four individuals underwent successful transplantation during the study period. There were no operative deaths or major complications. CONCLUSIONS: Pediatric VA missions to Guatemala created safe and functional AVFs in concert with local pediatric surgeons and pediatric nephrologists. Three surgical missions included access operations in 54 new patients. Cumulative AVF patency was 85% at 36 months.

Early results of percutaneous arteriovenous fistula creation with the Ellipsys Vascular Access System.

OBJECTIVE: We reviewed our initial experience creating a percutaneous arteriovenous fistula (pAVF) using a thermal resistance anastomosis device with proximal radial artery inflow. METHODS: A retrospective review was conducted of all patients who underwent a pAVF creation procedure between May 2017 and October 2017. Primary end points of the study were technical success, patency by Doppler ultrasound examination or angiography, flow levels achieved, time to first use, and pAVF-related complications. RESULTS: A pAVF was attempted in 34 patients with technical success in 33 individuals (97%). Patency of the pAVF was 94%. Mean access flow was 946 mL/min (brachial artery measurement) at the latest follow-up visit (53-229 days; average, 141 days). At 6 weeks, all fistulas have been used or were ready for dialysis by clinical examination or ultrasound examination. Only one patient required superficialization of the upper arm cephalic vein by lipectomy. There were no adverse events related to the pAVF creation or use, nor was there need for further interventions. CONCLUSIONS: Successful pAVFs with proximal radial artery inflow were created with excellent initial results regarding technical success, patency, and safety. Advantages include avoidance of a surgical incision, short procedure times, good acceptance by patients, prompt access maturation, moderate flow, and low-pressure access, with possible reduction of risk for ischemic complications. Avoidance of vessel manipulation and side branch ligation might reduce risk of thrombosis and improve long-term patency and reduce need for further interventions. These early findings need to be confirmed in larger and longer follow-up studies.

Proximal radial artery arteriovenous fistula for hemodialysis vascular access.

OBJECTIVE: This study reviewed our experience with proximal radial artery-based arteriovenous fistulas (PRA-AVFs) for hemodialysis vascular access, evaluating characteristics of the patients, functional patency, risk of steal syndrome, survival of the patient, and technical considerations. METHODS: We retrospectively analyzed our database of consecutive patients, identifying those individuals with a PRA-AVF created during a 12-year period. In addition to physical examination, all patients underwent ultrasound vessel mapping by the operating surgeon, identifying the PRA-AVF configuration and outflow target most likely to succeed. RESULTS: PRA-AVFs were created in 1396 individuals during the 12-year study period. The mean age was 59 years (standard deviation, ±15.9 years); 717 (51%) patients were women, 819 (59%) were diabetic, and 394 (28%) were obese. A transposition procedure was required in 400 patients, and 189 (47%) of these were completed in two-staged operations. Preoperative characteristics with a negative impact on PRA-AVF cumulative patency included female gender (hazard ratio, 1.90; 95% confidence interval, 1.37-2.65), obesity (hazard ratio, 1.92; 95% confidence interval, 1.40-2.65), and younger age. Dialysis-associated steal syndrome (DASS) requiring an intervention occurred in 39 (2.8%) patients, and 85% of these were diabetic. The most common procedures required to restore hand perfusion while preserving the AVF were banding and outflow branch ligation or coil occlusion to decrease access flow. DASS emerged spontaneously in 15 (1.1%) of the patients, and 24 (1.7%) individuals developed hand ischemia requiring intervention after fistulography with balloon angioplasty of the PRA-AVF anastomosis during the first years of the study period. Limiting angioplasty balloon size for such patients avoided these uncommon angioplasty-induced DASS events in later years. Primary, primary assisted, and cumulative (secondary) patency rates were 60%, 90%, and 93% at 12 months and 47%, 86%, and 91% at 24 months, respectively. Follow-up was 0.7 to 127 months (median, 25 months). CONCLUSIONS: PRA-AVFs offer excellent functional patency with low risk of dialysis access-related steal syndrome. The antecubital site has a wide range of venous outflow options for both direct PRA-AVFs and transposition procedures.