Efficacy and Safety of Plastic Cannulae Compared with Metal Needles in the Initial Use of an Arteriovenous Fistulae in Incident Hemodialysis Patients: A Randomized Controlled Study.

INTRODUCTION: Successful cannulation of an arteriovenous fistula (AVF) is important in patients starting hemodialysis (HD). Metal needles have been used for decades, but the usefulness of plastic cannulae has recently been demonstrated as a new technique. METHODS: This was a prospective, randomized, open-label study of incident HD patients. Eligible patients were randomized into 2 groups in a 1:1 ratio (n = 45/group). Maturation of the AVF was confirmed using Doppler ultrasound prior to first needling, and 2 well-trained nurses implemented the AVF cannulation. The primary endpoint was the initial cannulation failure rate, defined as the failure of successful completion of 3 consecutive dialysis sessions. The secondary endpoints were time for hemostasis at the end of HD, degree of patients' pain, degree of cannulation difficulty felt by the nursing staffs, and achieving optimal HD adequacy. RESULTS: The mean elapsed time from AVF creation to the first cannulation was 48.1 ± 16.7 days. A total of 17 cases of cannulation failure occurred, and the failure risk tended to be higher in the metal needle group than the plastic cannula group (hazard ratio 2.6, 95% confidence interval 0.95-7.41) after adjusting for age, gender, comorbidities, and AVF location. The overall incidence of vessel injury was higher and time for hemostasis was significantly longer in the metal group than the plastic group. The use of plastic cannula was associated with a better HD adequacy compared to a metal needle. However, the patients' pain score (p = 0.004) and nursing staff's cannulation difficulty score (p = 0.084) were higher in the plastic group, emphasizing the great importance of practice using plastic cannulae. CONCLUSION: The vascular outcomes of plastic cannulae were much favorable compared to metal needles in incident HD patients. The use of plastic cannulae could be a new and innovative way to improve the quality of dialysis.

Effectiveness of Flow Volume Measurement Training Using a Custom-Made Doppler Flow Simulator.

INTRODUCTION: This study was conducted to analyze the effectiveness of a custom-made Doppler ultrasound (DUS) flow simulator, vascular phantom, and Doppler test fluid in the training of dialysis staff in flow volume (FV) measurements for arteriovenous (AV) access in hemodialysis (HD) patients. METHODS: A DUS flow simulator was constructed using a continuous renal replacement therapy machine. Vascular phantoms were constructed using a rubber enema tube and keyboard cleaning gel. The Doppler test fluid consisted of freeze-dried instant coffee granules and 0.9% saline. This easy and affordable simulator was used to train 12 dialysis staff members, with no previous experience in DUS FV measurement. After a 3-day lecture course, the staff members performed DUS analyses on the AV access of HD patients. Thereafter, they underwent a 3-day training course using the simulator and then performed the DUS analyses of the AV access again. Each staff member assessed the FV 3 times, and the mean values of the measurements pretraining and posttraining were analyzed using paired t tests. RESULTS: The difference in the mean value of FV measurements and the reference value decreased from 131.6 mL/min to 62.5 mL/min (95% confidence interval = 30.0-108.0, P = 0.002), and the standard deviation of the FV measurements decreased from 96.9 mL/min to 47.0 mL/min (95% confidence interval = 7.9-91.8, P = 0.023) after DUS training with the simulator. CONCLUSIONS: The accuracy and reproducibility of FV measurements markedly improved after training with the simulator; it may be helpful for medical practitioners involved in AV access for HD treatment.

Comparison of dynamic arterial and venous pressure between metal needles and plastic cannulas in incident hemodialysis patients with arteriovenous graft.

BACKGROUND AND OBJECTS: We hypothesized that plastic cannulae with 17-gauge inner needle compared to 16-gauge metal needles can have stable dynamic venous and arterial pressure maintaining prescribed blood flow safely during a hemodialysis treatment. DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS: A single-center, prospective, randomized, open-label clinical trial was conducted involving 16 incident hemodialysis patients who had arteriovenous graft placed as their first arteriovenous access. Subjects were randomized to metal needle group (n = 8) versus plastic cannula group (n = 8). We measured serial dynamic pre-pump arterial and venous pressure under five different blood pump flow rates (150, 200, 250, 300, and 350 mL/min). RESULTS: The mean age of patients was 67.6 ± 8.5 (range: 51-81) years, and six patients (37.5%) were male. Patients with plastic cannula showed less negative arterial pre-pump pressures and lower venous pressures than those with metal needles at all prescribed blood flow rates, and the difference was statistically significant (P < 0.001). CONCLUSION: The plastic cannula had more stable arterial and venous pressures at prescribed blood pump flow rates than those pressures of the metal needle in incident patients with arteriovenous graft during hemodialysis.

Custom-made Doppler ultrasound flow simulator for dialysis access using continuous renal replacement therapy machine.

The purpose of this article was to introduce an easy and inexpensive way of making a simulator for training in Doppler ultrasound flow rate measurement using a continuous renal replacement therapy machine and home-made phantoms. A Doppler ultrasound flow simulator was made using a continuous renal replacement therapy machine and vascular phantoms for flow rate assessment of dialysis access with readily accessible components including rubber tube, keyboard cleaning gel, and freeze-dried instant coffee granules. The simulator is an affordable and easy method of Doppler ultrasound flow rate measurement training for dialysis staff using materials readily available in dialysis centers.

Anatomical variants of upper arm veins on preoperative mapping venography for hemodialysis access in Korean adults.

INTRODUCTION: The number of elderly patients requiring hemodialysis has increased, along with the need for multiple vascular access placements. Thus, the frequency of access creation using the upper arm veins, including transposed basilic arteriovenous fistula, has also increased. The purpose of this study was to identify the prevalence of anatomical variations in the upper arm veins on preoperative mapping venography and to investigate the implications of such variants on access creation. METHODS: A total of 494 venograms were performed on 251 patients for primary access creation from June 2014 to June 2017 in this single-center, retrospective study. The venograms were classified into eight subtypes, based on the anatomical relationship between the basilic and brachial veins. The presence of bifid cephalic arches and brachial-basilic ladders was also examined. RESULTS: The presence of bifid cephalic arches and brachial-basilic ladders was identified in 8.7% and 14.0% of cases, respectively. Paired brachial veins joined separately with the basilic vein in 67.4% of venograms, whereas these veins merged into a common brachial vein before connecting to the basilic vein in 13.1% of cases. A single brachial vein was present in 19.3% of cases. 15.7% of cases were considered unsuitable for basilic vein transposition due to the early confluence of the brachial-basilic vein, posing a risk of obliterating the deep venous drainage if transposed. CONCLUSION: There are significant anatomical variations of upper arm veins, and the recognition of certain variants can affect surgical planning and outcomes of access placement. It is important to identify anatomical variants of the upper arm veins during preoperative vein mapping.

Current treatment status and medical costs for hemodialysis vascular access based on analysis of the Korean Health Insurance Database.

BACKGROUND/AIMS: The Republic of Korea is a country where the hemodialysis population is growing rapidly. It is believed that the numbers of treatments related to vascular access-related complications are also increasing. This study investigated the current status of treatment and medical expenses for vascular access in Korean patients on hemodialysis. METHODS: This was a descriptive observational study. We inspected the insurance claims of patients with chronic kidney disease who underwent hemodialysis between January 2008 and December 2016. We calculated descriptive statistics of the frequencies and medical expenses of procedures for vascular access. RESULTS: The national medical expenses for access-related treatment were 7.12 billion KRW (equivalent to 6.36 million USD) in 2008, and these expenses increased to 42.12 billion KRW (equivalent to 37.67 million USD) in 2016. The population of hemodialysis patients, the annual frequency of access-related procedures, and the total medical cost for access-related procedures increased by 1.6-, 2.6-, and 5.9-fold, respectively, over the past 9 years. The frequency and costs of access care increased as the number of patients on hemodialysis increased. The increase in vascular access-related costs has largely been driven by increased numbers of percutaneous angioplasty. CONCLUSION: The increasing proportion of medical costs for percutaneous angioplasty represents a challenge in the management of end-stage renal disease in Korea. It is essential to identify the clinical and physiological aspects as well as anatomical abnormalities before planning angioplasty. A timely surgical correction could be a viable option to control the rapid growth of access-related medical expenses.

Clinical outcome of percutaneous thrombectomy of dialysis access thrombosis by an interventional nephrologist.

BACKGROUND: Traditionally, the treatment of a thrombosed dialysis access in hemodialysis patients in Korea has been primarily performed by vascular surgeons and interventional radiologists. The objective of this study was to evaluate the outcome of percutaneous thrombectomy procedures performed by an interventional nephrologist. METHODS: From October 2010 to May 2014, 75 consecutive percutaneous thrombectomies were performed on 42 patients treated with maintenance hemodialysis. All percutaneous thrombectomy procedures were performed by an interventional nephrologist in a single hospital in Jeju, Korea. The thrombosed arteriovenous graft and arteriovenous fistula were declotted by thromboaspiration mechanical thrombectomy or pharmacomechanical thrombolysis. Kaplan-Meier survival analysis was performed to analyze the primary and secondary patency after the initial successful thrombectomy. Success and complication rates were identified and compared with the recommendations of the Kidney Disease Dialysis Outcomes Quality Initiative (KDOQI) guideline. RESULTS: The overall clinical success rate was 89.3% (67/75). In the successful cases, the postintervention primary (unassisted) patency rates at 30 days, 90 days, and 180 days were 79.9%, 56.6%, and 25.6%, respectively. The secondary patency rates at 30 days, 90 days, and 180 days were 92.2%, 85.7%, and 83.7%, respectively. There were no major complications, and all complications were treated successfully during the procedure. CONCLUSION: The clinical success rate and primary patency rate at 3 months exceeded the recommendations of the KDOQI guideline, and were comparable to that of other reports. Percutaneous thrombectomy by an interventional nephrologist was safe and effective.