Role of Doppler ultrasonography in the evaluation of hemodialysis arteriovenous access maturation and influencing factors

The goal of vascular access creation is to achieve a functioning arteriovenous fistula (AVF) or arteriovenous graft (AVG). An autologous fistula has been shown to be superior to AVG or to central venous catheters (CVCs) with lowest rate of re-intervention, but vessel obstruction or immaturity accounts for 20 % to 54% of cases with primary failure of AVF. This review is focused on the factors influencing maturation; indication and timing of preoperative mapping/creation of vascular access; ultrasound parameters for creation AVF/AVG; early postoperative complications following creation of a vascular access; ultrasound determinants of fistula maturation and endovascular intervention in vascular access with maturation failure. However, vascular accesses that fail to develop, have a high incidence of correctable abnormalities, and these need to be promptly recognized by ultrasonography and managed effectively if a high success rate is to be expected. We review approaches to promoting fistula maturation and duplex ultrasonography (DUS) of evaluating vascular access maturation.

How to Reduce the Risk of Arteriovenous Fistula Dysfunction by Observing Prepump Arterial Pressure during Hemodialysis: A Multicenter Retrospective Study

OBJECTIVE

Prepump arterial (Pa) pressure indicates the ease or difficulty with which the blood pump can draw blood from the vascular access (VA) during hemodialysis. Some studies have suggested that the absolute value of the Pa pressure to the extracorporeal blood pump flow (Qb) ratio set on the machine (|Pa/Qb|) can reflect the dysfunction of VA. This study was conducted to explore the impact of arteriovenous fistula (AVF) dysfunction and to explore the clinical reference value of |Pa/Qb|.

METHODS

We retrospectively identified adults who underwent hemodialysis at 3 hospitals. Data were acquired from electronic health records. We evaluated the pattern of the association between |Pa/Qb| and AVF dysfunction during 1 year using a Cox proportional hazards regression model with restricted cubic splines. Then, the patients were grouped based on the results, and hazard ratios were compared for different intervals of |Pa/Qb|.

RESULTS

A total of 490 patients were analyzed, with an average age of 55 (44, 66) years. There were a total of 85 cases of AVF dysfunction, of which 50 cases were stenosis and 35 cases were thrombosis. There was a U-shaped association between |Pa/Qb| and the risk of AVF dysfunction (p for nonlinearity <0.001). |Pa/Qb| values <0.30 and >0.52 increased the risk of AVF dysfunction. Compared with the group with a |Pa/Qb| value between 0.30 and 0.52, the groups with |Pa/Qb| <0.30 and |Pa/Qb| >0.52 had a 4.04-fold (p = 0.002) and 3.41-fold (p < 0.001) greater risk of AVF dysfunction, respectively.

CONCLUSIONS

The appropriate range of |Pa/Qb| is between 0.30 and 0.52. When |Pa/Qb| is <0.30 or >0.52, the patient's AVF function or Qb setting should be reevaluated to prevent subsequent failure.

Predictive Value of 1-Week Postoperative Ultrasonography Findings for the Patency Rate of Arteriovenous Fistula

Introduction

Most guidelines in different countries recommend waiting more than 2 weeks for the initial cannulation of an arteriovenous fistula (AVF) after its creation. Although an experienced examiner can subjectively determine if an AVF is ready for early cannulation, there is a lack of objective information to guide whether early cannulation is appropriate or how early cannulation may affect an AVF’s primary patency. The current study examined the relationship between the initial cannulation and the prognosis of AVF, considering ultrasonography (US) findings.

Methods

This retrospective observational study enrolled 103 patients with end-stage renal disease who had started hemodialysis therapy from 2013 to 2015 at the Juntendo University Hospital. All patients had been given a primary AVF before or after the initiation of dialysis, had undergone US examinations both before and 7 days after surgery, had initially cannulated the AVF at ≥7 days after surgery, and were observed for over 1 year.

Results

The factor associated with the loss of primary patency was a resistance index of brachial artery ≥0.65 on US examination at 7 days after surgery. There was no significant difference in patency rate between the early (within 14 days after surgery) and late initial cannulation groups (≥15 days after surgery).

Conclusion

Because a resistance index <0.65 on US findings at 7 days after surgery was a good indicator for predicting an excellent patency rate when we performed first cannulation of AVF located in the forearm within 2 weeks after its creation, 1-week postoperative US evaluation may provide crucial information.

"Outcomes of arteriovenous fistulae cannulation in the first 6 weeks of use: A retrospective multicenter observational study"

BACKGROUND

Arteriovenous fistula (AVF) management for haemodialysis (HD) is one of the most challenging aspects of clinical care. A successful cannulation outcome when an AVF or arteriovenous graft (AVG) is used for the first time can be influenced by many factors, including access maturity, staff skill, and patient factors. This study examined AVF/AVG outcomes at initiation of HD across two major metropolitan public hospitals.

METHODS

Electronic medical records were reviewed to collect data retrospectively for a cohort of all newly commencing ESRD HD starts during 2018 to identify cannulation outcomes in the first 6 weeks.

RESULTS

Of the 117 patients included, AVG use was low (5%). Twenty-four percent of patients required a surgical intervention to salvage a poorly functioning AVF prior to commencing HD. About 32.5% of the cohort had an uneventful start with all successful cannulations. For the remainder of the cohort the number of treatments with unsuccessful cannulation ranged from 1 to 4 or more. About 36% required a surgical intervention for a poorly functioning AVF after commencing HD. Commencing HD with a CVC is associated with a lower likelihood of subsequent successful cannulation (p < 0.001).

CONCLUSION

Even in experienced centres, a subset of patients experienced complicated cannulation in the first 6 weeks of HD. Several areas of improvement could be considered for these patients; timely referral for access creation, post-operative surveillance to ensure AVF maturation inclusive of duplex ultrasonography, gentle induction using small gauge needles and low blood flows, and consideration of a single needle HD initiation pathway.

Cannulation practices at haemodialysis initiation via an arteriovenous fistula or arteriovenous graft

INTRODUCTION

A functioning long-term vascular access is required for haemodialysis therapy; however, establishing this can be challenging in the setting of advanced age and vessels damaged by diabetes. Complications include the inability to insert two needles for the treatment resulting in miscannulation trauma and in some cases insertion of a temporary central venous access device. The broad objective of this review is to define the evidence base regarding cannulation practices in the initiation of haemodialysis via an arteriovenous fistula or an arteriovenous graft.

METHODS

This review uses the framework recommended by the Joanna Briggs Institute and the process by which papers were included or excluded followed the standard Preferred Reporting Items for Systematic Reviews and Meta-Analyses group approach. A total of 20 primary research studies met the inclusion criteria.

RESULTS

Cannulation in the 10- to 15-week period rather than delaying past this time frame is associated with the best outcomes. New vascular access given time to mature through single-needle haemodialysis treatments may improve long-term patency. Duplex ultrasound mapping prior to initiation of cannulation supports the clinical decision-making process on timing of and selection of cannulation sites.

CONCLUSION

Cannulation trauma at the initiation of haemodialysis could potentially be reduced with a strategy of incremental haemodialysis using single-needle treatment supported with duplex ultrasonography assessment to 'map' the vascular access as a guide for clinicians prior to cannulation initiation.