Vascular imaging for hemodialysis vascular access planning

Minimizing delays to hemodialysis access maturation: A quality improvement analysis

INTRODUCTION

Pre-operative process optimization can expedite time-to-intervention and reduce overall health care costs. We hypothesized that the longest delay to hemodialysis (HD) access creation would be from pre-operative vessel mapping (mandatory in our practice), and that this would be correlated with increased catheter days.

METHODS

One hundred thirty patients (24 inpatients, 106 outpatients) who received initial hemodialysis (HD) access from 01/01/2017 to 12/31/2021, at the Veterans Affairs Puget Sound, Seattle, Washington, were identified. Median time differences between pre-operative events were compared between inpatients and outpatients using the Mann-Whitney U test. Outpatients were then stratified by time of catheter-based HD initiation (no catheter, pre-referral catheter, post-referral catheter) and compared. The impacts of mapping-related delays on catheter use were evaluated using regression.

RESULTS

Inpatients had shorter referral to access maturation times (125 days inpatient vs 146 days outpatient; p = 0.03). This was driven by shorter referral to mapping (2 days inpatient vs 27 days outpatient; p < 0.01) and mapping to pre-surgical evaluation (1-day inpatient vs 6 days outpatients; p < 0.01) times. Pre-surgical evaluation to OR times represented the longest pre-operative delay in both groups (51 days inpatient vs 29 days outpatient; p = 0.59). Among outpatients, tunneled catheter placement post-referral resulted in longer maturation times (74 days no catheter vs 67 days pre-referral vs 149 days post-referral; p < 0.01) but not additional pre-operative delays. No trend existed between increased mapping times and catheter-based dialysis duration (R2 = 0.08).

CONCLUSION

Preoperative vein mapping contributed up to 21% of referral to maturation times but was not associated with increased tunneled catheter duration. While tunneled catheter placement impacted access maturation it did not cause additional pre-operative delays. Earlier referrals for access creation and reduction of outpatient wait-time from referral to OR and increased AV graft placement may minimize catheter days in our system thereby mitigating the added delays caused by pre-operative vein mapping.

Pre-procedure imaging planning for dialysis access in patients with end-stage renal disease using ultrasound and upper extremity computed tomography angiography: a narrative review

Background and Objective

The incidence of patients with end-stage renal disease (ESRD) and subsequent need for dialysis is continuously rising. The detailed preoperative planning and careful creation of a functioning access for hemodialysis as a bridge to transplant or as a long-term solution, has a crucial role to reduce vascular access associated morbidity and mortality and improve quality of life of the ESRD patient population. In addition to a detailed medical workup including physical exam, a variety of imaging modalities exist to support further decision making with regard to the best suited vascular access for each individual patient. These modalities provide both, a comprehensive anatomical overview of the vascular tree and specific pathologic findings, which may increase the likelihood of access failure or insufficient access maturation. This manuscript aims to provide a comprehensive review of current literature and an overview of the different imaging modalities in vascular access planning. Additionally, we provide a step-by-step planning algorithm for hemodialysis access creation.

Methods

After searching in PubMed and Cochrane database of systematic review, we reviewed eligible English literatures published up to 2021, including guidelines and meta-analyses, retrospective and prospective cohort studies.

Key Content and Findings

Duplex ultrasound is widely accepted as first line imaging tool for preoperative vessel mapping. However, this modality has its inherent limitations, therefore specific questions can be assessed using digital subtraction angiography (DSA) or venography and computed tomography angiography (CTA). These modalities are more invasive, are associated with radiation exposure and require nephrotoxic contrast agents. Magnetic resonance angiography (MRA) may be an alternative in selected centers with available expertise.

Conclusions

Pre-procedure imaging recommendations are mainly based on retrospective (register-) studies and case-series. Prospective studies and randomized trials are primarily related to access outcomes in ESRD patients who underwent preoperative duplex ultrasound. Comparative prospective data related to invasive DSA and non-invasive cross-sectional imaging (CTA or MRA) are lacking.

Pediatric hemodialysis access

Pediatric hemodialysis access is a demanding field. Procedures are infrequent, technically challenging, and associated with high complication and failure rates. Each procedure affects subsequent access and transplants sites. The choice is made easier and outcomes improved when access decisions are made by a multidisciplinary, pediatric, hemodialysis access team. This manuscript reviews the current literature and offers technical suggestions to improve outcomes.

Association of preoperative vein mapping with hemodialysis access characteristics and outcomes in the Vascular Quality Initiative

BACKGROUND

Preoperative vein mapping before arteriovenous fistula (AVF) or arteriovenous graft (AVG) placement has been debated as a possible method of improving hemodialysis access outcomes for patients. However, high-quality national studies that have addressed this relationship are lacking. Thus, we assessed the association of preoperative vein mapping with hemodialysis access configuration and outcomes.

METHODS

In the present cohort study, we analyzed all patients who had undergone AVF or AVG placement with data captured in the Vascular Quality Initiative hemodialysis access dataset from August 2011 to September 2019. The patients were stratified by whether they had undergone preoperative vein mapping. The primary (configuration) outcomes were access type (AVF vs AVG) and location (upper arm vs forearm). The secondary (longitudinal) outcomes were the successful initiation of hemodialysis, maintenance of secondary patency, and the need for reintervention 1 year after the index operation.

RESULTS

Overall, 85.6% of the 46,010 included patients had undergone preoperative vein mapping. Of the 46,010 patients, 76.1% and 23.9% had undergone AVF and AVG creation, respectively. AVF creation (77.6% vs 67.3%) and forearm location (54.6% vs 47.3%) were more frequent for the patients who had undergone preoperative vein mapping than for those who had not (P < .001). After adjusting for baseline differences between the groups, preoperative vein mapping was associated with increased odds of receiving an AVF vs AVG (adjusted odds ratio, 1.64; 95% confidence interval [CI], 1.55-1.75) and forearm vs upper arm access (adjusted odds ratio, 1.22; 95% CI, 1.16-1.30). The incidence of the loss of secondary patency was lower for patients with preoperative vein mapping (P < .001), and persisted after risk adjustment (adjusted hazard ratio, 0.81; 95% CI, 0.75-0.88).

CONCLUSIONS

Preoperative vein mapping was associated with favorable hemodialysis access configurations and outcomes in real-world practice. These data suggest that the use of preoperative vein mapping could improve the likelihood of favorable outcomes for patients requiring hemodialysis access.

Outcomes of arteriovenous fistula reconstruction in vascular access dysfunction

BACKGROUND

Complications such as stenosis, thrombosis, aneurysmal dilatation, and infection occur in at least one-third of all arteriovenous fistulas (AVFs). Due to these complications, vascular access dysfunction develops in hemodialysis patients.

OBJECTIVES

We investigated AVF rescue operations, which we performed for the pathologies causing dysfunctional vascular access, and outcomes of these operations by surgeon-performed preoperative ultrasound (US) in our clinic.

DESIGN

Retrospective Study.

SETTINGS

Bursa Yüksek Ihtisas Training and Research Hospital Cardiovasculary Surgery Department, Turkey.

PATIENTS AND METHODS

67 patients who were treated in our clinic due to AVF dysfunction between January 2012 and January 2016 were included in the study. Preoperative US evaluation for dysfunctional AVFs was performed by the surgeon conducting the operation. The patients were divided into 5 groups according to the pathologies such as stenosis, thrombosis, aneurysm, high-flow rate, and deep basilic vein.

MAIN OUTCOME MEASURES

Our goal in all patients with vascular access dysfunction was to maintain the AVF.

SAMPLE SIZE

67 Patients.

RESULTS

In Group 1 (16 patients) which had stenosis and underwent AVF reconstruction, the 24-month primary patency rate was 81.3%. In Group 2 (9 patients) which had trombosis and underwent AVF reconstruction, the 24-month primary patency rate was 22.2%. In Group 3 (24 patients) which had AVF aneurysm and underwent AVF reconstruction, the 24-month primary patency rate was 70.8%. In Group 4 (10 patients) which had high flow and underwent AVF reconstruction, the 24-month primary patency rate was 90%. In Group 5 (8 patients) which had deep basilic vein and underwent AVF reconstruction, the 24-month primary patency rate was 75%.

CONCLUSION

Leaving patients with vascular access dysfunction to fate (no intervention) or AVF ligation is always simpler and easier. However, it should not be forgotten that paternity for vascular access are limited in these patients. We think that the primary target is to demonstrate AVF by physical examination and surgeon-performed detailed US and to make it again available for hemodialysis by reconstructing dysfunctional AVF using the most appropriate surgical strategy.

LIMITATIONS

Retrospective, small sample size.