UNASSIGNED: The preferred techniques for peritoneal dialysis catheterization are uncertain. Catheter implantation with formation of an inferiorly-directed tunnel and exit site is widely recommended to reduce the risk of infective complications. We aimed to compare percutaneous peritoneal dialysis catheter insertion using an upwardly-directed tract to catheter insertion using a downwardly-directed tract.
UNASSIGNED: A retrospective cohort study was performed on consecutive peritoneal dialysis catheterizations over a 10-year period at a single centre. Participants were classified into two groups: catheter insertion with an upward tunnel and exit site versus insertion with a downward tunnel and exit site. The primary outcome was peritoneal dialysis catheter survival.
UNASSIGNED: There were 247 peritoneal dialysis catheters inserted during the study period. The median catheter survival was 18 months, with no difference between the two groups (p = 0.23). The 12-month catheter patency rates were 76% for catheters with an upward tract and 79% for catheters with a downward tract (p = 0.15). Multivariate analysis identified no clinical factors predictive of catheter survival. A downward catheter tunnel and exit site was associated with an increased incidence of peritonitis (0.23 vs 0.11 episodes per year; p ⩽ 0.01).
UNASSIGNED: In this study, percutaneous peritoneal dialysis catheter insertion with an upward tunnel and exit site demonstrated similar catheter survival to insertion with a downward tunnel and exit site and was not associated with increased infections.

BACKGROUND: A mature arteriovenous fistula (AVF) is the preferred hemodialysis access due to its durability and lower risk of complications. Various factors have been implicated as predictors for maturation, including vein diameter and access type. Vein distensibility, which refers to the ability of the vein to dilate in response to changes in blood flow and pressure, has been proposed as a potential predictor for maturation, but its utility remains poorly studied.
METHODS: This is a single institution retrospective study of AVFs performed under regional anesthesia. Vein distensibility was defined as the absolute and relative difference in target vein diameter (TVD) between the preoperative ultrasound vein mapping performed with tourniquet and a repeat ultrasound after a regional block prior to the AVF creation and without a tourniquet.
RESULTS: 46 patients were underwent first time AVF surgery and had distensibility captured in a prospectively maintained database. The mean initial preoperative TVD was 2.7mm and after the block 3.4mm. The unassisted maturation rate for the entire cohort was 76%. In patients with an absolute change of TVD of <0.5mm (Δ<0.5), the unassisted maturation rate was 63% (12/19), even though 95% of the group had a preoperative TVD >3mm. In those with Δ≥0.5mm, the unassisted maturation rate was 85% (23/27, P = 0.08), even though the preoperative vein map TVD was 2.3 mm and 75% had a vein map TVD <3mm. For radiocephalic AVFs (n=26), the unassisted maturation rate was 75% for Δ<0.5 vs 94% for Δ≥0.5 (P=0.16), despite a preop vein map TVD >3mm in 92% vs 75%, respectively. The ROC area under the curve for unassisted maturation with Δ≥0.5 mm was 0.68 (P=0.26).
CONCLUSIONS: Quality in dialysis access surgery requires optimizing the unassisted maturation rate. A physiologic measure that accounts for the dynamic process of maturation may be more informative than anatomic measurements alone. The results shown here demonstrate that vein distensibility may be a better predictor than absolute vein diameter on standard vein mapping ultrasounds.

Central venous obstructions that impedes catheter placement or results in catheter dysfunction is a significant problem for haemodialysis patients. Recanalization can be performed with an intent to restore central venous access, improve outflow from arteriovenous fistula or to relieve symptomatic venous obstructions. Sharp recanalization encompasses various interventional techniques using a sharp instrument to puncture through or bypass around a venous obstruction. In this paper we outline our experience performing CT guided sharp recanalization and review alternative sharp recanalization techniques that are specifically used to restore haemodialysis access in patients with thoracic central venous obstruction.

BACKGROUND: Currently, there are two types of percutaneous arteriovenous fistula (pAVF) formation systems approved by the FDA: Ellipsys and WavelinQ. Although these systems are already in use in Europe or the United States, they have not been approved for use in Korea yet. For this reason, this study aimed to check anatomical feasibility of these systems for Korean population prior to their actual use.
METHODS: Consecutive patients who received ultrasound vein mapping for arteriovenous fistula formation from June 2021 to June 2022 were included. The anatomical feasibility of each system was confirmed according to the manufacturer\'s instructions for use (IFU).
RESULTS: Upper extremity ultrasonography was performed for a total of 83 patients to determine their feasibility for pAVF formation. Of these patients, 65.1% were feasible for pAVF formation with appropriate deep communicating vein (DCV) and outflow. Among them, 57.8% were feasible for the Ellipsys system and 54.2% were feasible for the WavelinQ system. Most patients who were infeasible for pAVF formation had a DCV of small size. Ulnar vessels were more suitable than radial vessel for WavelinQ (54.2% vs 33.7%, P-value = .012). The most common reason for not meeting the criteria was a small vein size at the access site.
CONCLUSIONS: More than half of all patients were feasible for pAVF formation in this study. Ellipsys had a higher feasibility than WavelinQ, although they showed no significant difference in the feasibility. If these devices are imported into Korea, it will be a good opportunity for many patients to reduce the surgical burden and create AVFs more easily through these procedures.

Background Nephrology services encompass a wide range of day-care procedures. Securing beds for day admissions can be challenging and may lead to significant delays in patient management. Objective This study aims to describe the impact of establishing a dedicated nephrology daycare unit at a tertiary care center. Methods Since January 2021, a dedicated nephrology daycare unit has been operational at King Abdulaziz University Hospital (KAUH) in Jeddah, Saudi Arabia. This observational study retrospectively reviewed the admission records to the KAUH nephrology daycare unit from January 2021 to December 2023. Admissions with missing data were excluded from the analysis. The study outcomes included: 1. the number of patients served in the unit, 2. the scope of services provided, 3. the \"time to completion\" of immunosuppressive therapy administered in the unit, and 4. the rate of complications related to admission to the unit. Results There were 233 admissions for 157 patients. The scope of procedures included: 1. administration of immunosuppressive therapy (42 doses of cyclophosphamide, 70 doses of rituximab, three doses of methylprednisolone), 2. renal biopsies (25 procedures), 3. tunneled dialysis catheter procedures (40 procedures, both insertion and removal), 4. dialysis access angioplasty (three procedures), 5. IV iron therapy (45 admissions), and 6. other miscellaneous causes (five admissions). Ideal time to completion of cyclophosphamide therapy was achieved in 86% of patients, with the remaining 14% experiencing delays due to reasons other than bed availability. Time to completion of rituximab therapy was achieved without delay in 85% of patients, with a time interval of less than 21 days. There were no reported complications associated with admission to the unit. Conclusions Establishing a dedicated nephrology daycare unit facilitates the delivery of nephrology day-procedures and reduces delays in therapy.

UNASSIGNED: Oscillatory wall shear stress and related metrics have been identified as potential predictors of dialysis access outcomes; however, the absence of a simple non-invasive method for measuring these haemodynamic forces has been prohibitive to their adoption into routine clinical practice. We present a computationally enhanced, single patient case study, offering a unique insight into the haemodynamic environment surrounding the development of flow limiting neointimal hyperplasia within the efferent vein of a previously functional arteriovenous fistula (AVF).
UNASSIGNED: Computational fluid dynamics (CFD) simulations were used to create a quantitative map of oscillatory shear stress as well as enabling visualisation of streamline patterns within the AVF. CFD data was compared to ultrasound-based turbulence quantification and examined alongside structural and functional changes in the access site over time.
UNASSIGNED: This work further supports the notion that flow limiting neointimal hyperplasia development in vascular access fistulae, occurs in response to oscillatory wall shear stress, and provides proof of concept for the idea that non-invasive ultrasound turbulence quantification tools could play a role in predicting vascular access outcomes.
UNASSIGNED: In addition to providing insight into the haemodynamic environment surrounding the development of flow limiting neointimal hyperplasia, we hope that this paper will promote discussion and further thinking about how our learnings from in-silico studies can be incorporated into clinical practice through novel uses of existing diagnostic tools.

OBJECTIVE: To compare the primary patency and restenosis rates in treatment naieve dialysis arteriovenous fistulas (AVFs) after drug-coated balloons (DCB) versus plain balloon angioplasty (PTA).
METHODS: This retrospective study included 157 patients who underwent AVF angioplasty for treatment-native AVF stenosis between January 2012 to 2022. The fistulas were Brachiocephalic (75%), Brachiobasilic (17%), and radiocephalic (8%). The index intervention was with either DCB or percutaneous transluminal angioplasty (PTA) with subsequent follow up. Patients with central venous stenosis, thrombosed fistula, fistula stents, AV graft or surgical intervention after the index procedure were excluded.
RESULTS: Arteriovenous fistula angioplasty was done in 28 patients using DCB and in 129 patients using PTA. A total of 108 patients presented with a single stenosis, 42 with 2 stenoses, and 7 with 3 stenoses. The location of these stenoses was in the venous outflow (57%), the juxta anastomotic segment (31%), and cephalic arch (12%). The median time to re-intervention for the PTA was 216 days compared to 304 days for the DCB (p=0.079). Primary patency at 6 months was 60.4% for PTA and 75% for DCB (p=0.141) CONCLUSION: Although DCB angioplasty of treatmentnaïve dysfunctional AVF tends to improve the time to intervention and 6-month primary patency compared to PTA, this difference did not reach statistical significance.

The use of a drug-coated balloon (DCB) to treat dysfunctional arteriovenous fistula (AVF) has shown promising results. After percutaneous coronary intervention with DCB, late lumen enlargement (LLE) often develops in the early follow-up phase, but questions regarding the natural history of changes in lesions after DCB angioplasty have not been clearly elucidated. Here, we reported on a patient in whom angiography and angioscopy were performed immediately and 4 months after DCB angioplasty to treat cephalic vein stenosis of the dysfunctional AVF. Immediately after DCB application, angiography showed good dilatation and blood flow and mild vascular dissection that did not affect blood flow. Angioscopy showed that although the balloon had damaged the intima and the paclitaxel particles had adhered to the vessel wall. Four months after DCB treatment, follow-up angiography and angioscopy were performed. Angiography showed LLE in the cephalic vein of the AVF that had been treated by DCB angioplasty. Angioscopy showed that the intima of the vessel had almost completely healed, and the paclitaxel particles had disappeared. LLE might occur when DCB is used for AVF.

Patients with threatened arteriovenous access are often found to have central venous stenoses at the ipsilateral costoclavicular junction, which may be resistant to endovascular intervention. Stenoses in this location may not resolve unless surgical decompression of thoracic outlet is performed to relieve the extrinsic compression on the subclavian vein. The authors reviewed the management of dialysis patients with central venous lesions at the thoracic outlet, as well as the role of surgical decompression with first-rib resection or claviculectomy for salvage of threatened, ipsilateral dialysis access.

UNASSIGNED: Arteriovenous grafts (AVGs) serve as an alternative to native arteriovenous fistulas (AVFs) in the context of hemodialysis patient life planning. AVGs are more susceptible to developing outflow stenosis (due to intimal hyperplasia), thrombosis, and infections. However, an often overlooked contributor to AVG failure is cannulation damage. The objective of this paper is to assess the impact of cannulations on AVGs. We aim to establish a classification of AVG damage by comparing clinical data and ultrasound images with microscopic morphological findings obtained from explanted grafts.
UNASSIGNED: This study is conducted at a single center. We included all patients who underwent AVG creation between 2011 and 2019. Comprehensive data on clinical history, follow-up, and complications were collected and reviewed. Duplex ultrasound (DUS) characteristics were documented, and all grafts explanted during the analysis period underwent optical microscopy evaluation. Finally, clinical data, along with DUS and microscopic findings, were integrated to derive a damage classification.
UNASSIGNED: During the study period, 247 patients underwent 334 early cannulation AVGs. The median follow-up duration was 714 days (IQR 392, 1195). One hundred eleven (33%) grafts were explanted. Clinical data and DUS findings were utilized to formulate a four-grade classification system indicating increasing damage.
UNASSIGNED: Cannulation damage alone does not solely account for AVG failure. It results from a biological host-mediated process that promotes the growth of intimal hyperplasia at the cannulation sites. This process is not clinically significant within the initial 2 years after AVG creation.