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.

Endovenous saphenous vein ablation in patients with acute isolated superficial-vein thrombosis.

OBJECTIVE: The possible benefits of endovenous saphenous ablation (EVSA) as initial treatment in patients presenting with isolated superficial-vein thrombosis (SVT) and saphenous vein reflux include: (1) definitive treatment of the underlying pathology and (2) elimination of the saphenous vein as a path for pulmonary emboli, which (3) may eliminate the need for anticoagulation. METHODS: In a ten-year review of 115 limbs presenting with acute isolated SVT, 72 limbs (71 patients) with saphenous reflux were given a choice of two treatments following an explanation of the risks and benefits of each. Group I limbs (n = 41) were treated with office EVSA using radiofrequency or laser with or without thrombophlebectomy if performed within 45 days of diagnosis. Post-treatment anticoagulants were not given. Group II limbs (n = 31) were treated with compression hose and repeat Duplex within one week, with added anticoagulants if SVT extended into the thigh. RESULTS: In group I, mean interval from diagnosis to treatment was 13.7 days. One calf deep vein thrombosis was noted. In group II no complications were noted. In late follow-up of group II patients, 12/29 underwent EVSA more than 45 days after initial presentation. CONCLUSIONS: The safety and efficacy of EVSA and thrombophlebectomy appear indistinguishable from conservative measures and may be offered as initial treatment to patients presenting with SVT and saphenous reflux.

Outcomes with arteriovenous fistulas in a pediatric population.

OBJECTIVE: Kidney Disease Outcome Quality Initiative guidelines recommend permanent access in dialysis patients aged 0 to 19 years who weigh >20 kg and are unlikely to receive a transplant within 1 year. Unfortunately, >80% of these patients currently receive dialysis through a permanent catheter and are exposed to the associated risks and shortcomings. With a clear imperative to increase the incident use of permanent access in pediatric patients, our objective was to examine the long-term outcomes of pediatric arteriovenous fistulas (AVFs). METHODS: A retrospective review was performed of all AVFs created in a hemodialysis (HD) population aged 0 to 19 years at a single institution from 1999 to 2012. Data abstracted included age, weight, etiology of renal failure, time on dialysis, central venous catheter history, and transplantation history. Data were analyzed to determine the influence of these variables on primary and secondary patency. RESULTS: During the study period, 101 AVFs were performed in 93 patients, of whom 65 patients (70%) were male. Mean patient age was 14 years (range, 3-19 years), and mean weight was 51 kg (range, 12-131 kg). At the time of AVF creation, 66 patients (82%) were already receiving HD, with a mean length of HD dependence of 18 months. At the time of surgery, 78% of patients had a previous central venous catheter, and 24% had two or more catheters. Procedures performed included 43 radiocephalic fistulas, 29 brachiocephalic fistulas, 20 basilic vein transpositions, and 9 femoral vein transpositions. Mean follow-up was 2.5 years. The 2-year and 4-year primary and secondary patency rates were 83% and 92%, and 65% and 83%, respectively. Increasing age was correlated with improved primary patency (P = .02) but had no effect on secondary patency. Weight, etiology, catheter location, and catheter history were not significantly associated with primary or secondary patency. During the postoperative period, 68 patients (75%) received a renal transplant, with a mean time to transplant of 556 days. CONCLUSIONS: AVFs demonstrate excellent long-term patency with minimal complications in pediatric HD patients, regardless of weight. Concerted efforts should be made to improve the incident use of AVFs in all pediatric patients with end-stage renal disease.

Adjunctive proximal vein ligation with endovenous obliteration of great saphenous vein reflux: does it have clinical value?

The risk of clot extension to the deep venous system or pulmonary embolism following endovenous great saphenous vein (GSV) obliteration is possibly related to the size of the proximal GSV. Some practitioners therefore exclude endovenous GSV obliteration for veins greater than an arbitrary size, starting as little as 15 mm. Others provide adjunctive proximal GSV ligation either routinely, or in selected patients with large veins. The clinical value of adjunctive proximal GSV ligation is unknown. A survey of either the American Venous Forum or the American College of Phlebology, selected for their pedagogic or long-time experience with endovenous GSV obliteration. Respondent characteristics included obliteration technique (laser, radiofrequency [RF], or foam sclerotherapy), academic status, surgical training, indication for and frequency of adjunctive proximal GSV ligation, and society membership. The incidence of pulmonary embolus (PE) and deep vein thrombus (DVT) was also tallied. Twenty-one thousand nine hundred sixty-five endovenous GSV obliteration cases were reported, 10,290 with a laser (46.8%), 6,275 (28.6%) with RF, and 5,400 (24.6%) with foam. Only two PEs were reported. Of the 34 patients with DVT, at least 11 had only asymptomatic ultrasound evidence of thrombus extension into the femoral vein, and at least five had only calf vein thrombosis. Comparing ligators (7) with non-ligators (15), the only characteristic significantly correlating with adjunctive proximal GSV ligation was whether the respondent had complete general or vascular surgical training; non-surgeons never ligated the saphenous vein (p < .001). There was no difference between outcomes of ligators and non-ligators. Endovenous obliteration of the GSV poses little risk of PE or DVT, no matter what size the proximal GSV. Although these adverse events may be reduced with adjunctive proximal GSV ligation, the results of this study suggest that adjunctive proximal GSV ligation is superfluous in most patients.

Experience with autogenous arteriovenous access for hemodialysis in children and adolescents.

The National Kidney Foundation's DOQI-NKF recommendation to construct an autogenous arteriovenous access (AAVA) for chronic hemodialysis whenever possible can be a challenge in the pediatric population. This report reviews recent surgical experience in this patient subgroup. From March 1999 to April 2004, 47 consecutive children requiring permanent vascular access had construction of AAVA. There were 16 girls and 31 boys, with a mean age of 14.6 years (range 5-20). The surgeon preoperatively mapped veins with ultrasound in all patients. Access sites were radial-cephalic (n = 16), upper arm brachial-cephalic (n = 15), transposed upper arm brachial-basilic (n = 7), and transposed femoral vein (n = 9). An operating microscope was used to construct three radial-cephalic accesses in individuals with small arteries. Three forearm cephalic veins were transposed (one at the original surgical procedure and two postoperatively). Five upper arm cephalic veins were transposed (three at the original surgical procedure and two postoperatively). Femoral vein accesses were constructed for either exhausted access in the upper extremities (n = 7) or patient preference (n = 2). Primary patency at 1 and 2 years was 100% and 96%, respectively. Secondary patency at 1 and 2 years was 100%. One individual with a radial-cephalic AAVA and severe radial artery calcification required an inflow procedure. Thirty-five accesses are currently in use (functionally patent), eight are in individuals with successful renal transplants, and two are maturing; one individual declines using the access. Two accesses are secondarily patent (thrombosed and repaired 12 and 29 months after construction, respectively), and one access thrombosed after 27 months (abandoned). Construction of an AAVA is possible in virtually all pediatric age individuals if attention is given to preoperative vein mapping, selective use of an operating microscope, and creation of a transposed femoral vein when upper extremity access is neither possible nor desired.

Femoral vein transposition for arteriovenous hemodialysis access: improved patient selection and intraoperative measures reduce postoperative ischemia.

PURPOSE: Construction of prosthetic arteriovenous access for hemodialysis in the thigh results in a high incidence of graft failure and infection. Autogenous femoral artery-common femoral thigh transposition (transposed femoral vein [tFV]) arteriovenous accesses have superior patency, but our previous report documented a high incidence of ischemic events requiring secondary surgical intervention. Recent results of improved patient selection and intraoperative maneuvers to reduce ischemia are unknown. METHODS: During a 6-year period eight children (mean age, 13.3 years) and 46 adults (mean age, 52.3 years; 27 female, 19 male) underwent construction of 55 tFV thigh accesses for hemodialysis access. Adult patients were divided into groups I and II on the basis of the introduction of specific strategies to reduce the incidence of ischemic complications. In the cohort of children, steal prophylaxis included one banded femoral vein, three tapered femoral veins, two distal femoral artery pressure measurements taken before and after access construction (mean ratio, 0.70), and two closed anterior and superficial posterior compartment fasciotomies. Of the first 25 accesses in adults (group I, mean age, 55.9 years), 10 had access banding (six at the initial procedure and four in the immediate postoperative period to treat ischemia). Of the second 22 accesses (group II, mean age, 48.2 years), steal prophylaxis included 14 tapered femoral veins, 6 distal femoral artery pressure measurements (mean ratio, 0.76; range, 0.62 to 0.86), and 1 fasciotomy. Patients with significant distal occlusive disease were not offered a tFV access in the time frame of group II. RESULTS: Eight accesses in children had 100% primary functional patency at 2 years, with no reoperations for ischemia. Nine group I adult patients underwent remedial procedures to correct distal ischemia. No adult patient in group II required a remedial procedure to correct ischemia. Groups I and II 2-year secondary functional access patency was 87% and 94%, respectively. There were no access infections in either group. Femoral vein tapering significantly reduced the need for remedial correction of ischemia ( P = .03). CONCLUSIONS: Improved patient selection and selective intraoperative femoral vein tapering eliminated remedial procedures to correct ischemia in patients undergoing tFV access. Patency rates were excellent despite the liberal use of vein tapering. Transposed FV access should be considered for good risk individuals undergoing their first lower extremity access.

Analysis of options for mitigating hemodialysis access-related ischemic steal phenomena.

Steal phenomena associated with brachial bridge grafts for hemodialysis access may compromise blood flow to the forearm. This work is designed to investigate and compare, by means of a simple mathematical model, the potential of six surgical procedures to alleviate steal. A flow model based on an electrical analogue was developed. An untapered 6-mm prosthetic brachial-axillary access (PBAA) was selected as the prototype configuration, and the theoretical effect of six access modifications on forearm flow was analyzed. Major simplifications include the use of Poiseuille's law for estimating arterial resistance and ignoring the contribution of collateral circulation. Intra-operative flow measurements using a Transonic flowmeter were obtained in two individuals undergoing treatment for a steal syndrome. The flow model predicts that the greatest increase in distal flow is achieved by the distal revascularization-interval ligation (DRIL) procedure, followed by a 6-mm axillobrachial artery bypass graft without interval ligation, the conversion of the PBAA to an axillary-axillary loop access, and the conversion to an axillary-brachial access. Intra-operative measurements in two patients agreed closely with theoretical calculations. A simple flow model provides a tractable framework for comparing procedures designed to avoid or treat steal phenomena. Distal revascularization without interval ligation and the conversion of a PBAA to an axillary-axillary loop access or an axillary brachial access can be effective alternatives to the DRIL procedure in selected clinical settings.