Maturation Rates of Arteriovenous Fistulas Using Small Veins in the Era of Endovascular Interventions

Rejoining Veins for Forced Maturation of Small-Caliber Arteriovenous Fistula

BACKGROUND

To evaluate the efficacy of rejoining mainstream and accessory veins for forced maturation of autogenous arteriovenous fistula (AVF).

METHODS

Twenty-three patients who underwent forced maturation through vein rejoining between January 2018 and September 2022 were included. In cases where AVF maturation failure due to the presence of accessory veins, rejoining was primarily considered when distinguishing the main branch becomes challenging. This difficulty typically occurs when the sizes of the 2 vessels are nearly equal and the combined diameters of these veins exceed 6 mm.

RESULTS

The mean age and follow-up duration were 57.39 ± 16.22 years and 965.65 ± 573.42 days, respectively. Rejoining of both arterial and venous cannulation sites was performed in 11 patients (47.8%), and rejoining of only the venous cannulation site or only the arterial cannulation site was performed in 11 patients (47.8%) and 1 patient (4.3%), respectively. The mean vein size was 0.35 ± 0.06 cm before rejoining and 0.69 ± 0.07 cm after surgery, indicating a significant increase in size (P < 0.01), whereas the flow did not change significantly following rejoining surgery. Maturation and cannulation success was 100%. The 1-year primary patency rate after surgery was 82.0%. During the follow-up period, 34.8% of the patients required additional percutaneous transluminal angioplasty to maintain patency, and 2 patients (11.8%) had stenosis in the rejoined section.

CONCLUSIONS

Rejoining surgery is an effective method for achieving AVF maturation in patients with accessory veins when identification of the mainstream vein is difficult, and this method may be considered when achieving maturation by sacrificing 1 vein is expected to be challenging.

Improved Ultrasound-Guided Balloon-Assisted Maturation Angioplasty Using Drug-Eluting Balloons in the First Autogenous Arteriovenous Fistula Procedure: Early Experience

In patients with end-stage renal failure requiring hemodialysis, autogenous arteriovenous fistula (AVF) is preferred over tunneled dialysis catheters due to lower complications and costs. However, AVF maturation failure remains a common issue due to small vein size, multiple venipunctures, and other factors. Guidelines recommend using vessels of >2 mm for forearm AVFs and >3 mm for upper arm AVFs. This study investigates the use of intraoperative Doppler ultrasound (DUS)-guided Balloon-Assisted Maturation (BAM) with drug-eluting balloons (DEB) during initial AVF creation. Data from 114 AVF procedures, of which 27.2% underwent BAM, were analyzed. BAM was performed in 25 distal radio-cephalic and 6 proximal brachio-cephalic AVFs. With DUS guidance, vein stenosis was identified and treated using DEB. Technical success was achieved in all cases, with no early mortality. Early BAM-related complications were minimal, and no AVF thrombosis occurred. AVF maturation time was 15 days (SD: 3), and no further complications were reported during a mean follow-up of 10.38 months. Using BAM with DEB during AVF creation led to successful maturation and dialysis use without the need for secondary procedures. This study emphasizes the importance of identifying AVF failure risk early and utilizing DUS-guided procedures to enhance AVF outcomes. A more liberal use of intraoperative BAM could limit reinterventions in patients undergoing AVFs.

Cost-effectiveness analysis of endovascular vs surgical arteriovenous fistula creation in the United States

OBJECTIVE

In the United States, an estimated $2.8 billion annually is spent on vascular access and its complications. Endovascular arteriovenous fistula (endoAVF) creation is a novel, minimally invasive alternative to traditional surgical AV fistula (sAVF) creation in ≤60% of patients. Although cost effective in single-payer systems, the clinical and financial impact of endoAVF in the United States remains uncertain.

METHODS

We constructed a decision tree followed by a probabilistic cohort state-transition model to study the cost effectiveness of endoAVF vs sAVF creation. We conducted a systematic review to obtain input parameters including technical success, maturation, patency, and utility values. We derived costs from the Medicare 2022 fee schedule and from the literature. We used a 5-year time horizon, an annual discount rate of 3% for costs and utilities (measured in quality-adjusted life-years [QALYs]), and the common willingness-to-pay threshold of $50,000. One-way and Monte Carlo probabilistic sensitivity analyses were performed varying technical success, patency, reintervention, cost, and utility parameters.

RESULTS

In the base-case scenario, endoAVF ($30,129 average per-person costs, 2.19 QALYs gained, 65% patent at 5 years) was not cost effective compared with sAVF ($12.987 average per-person costs, 2.11 QALYs gained, 66% patent at 5 years), generating an incremental cost-effectiveness ratio of $227,504 per QALY gained. In one-way sensitivity analyses, endoAVF becomes cost effective when the initial cost of sAVF creation exceeds endoAVF by ≥$600 (eg, if endoAVF creation costs ≤$3000 relative to the base-case sAVF cost of $3600), the additional QALYs gained from endoAVF exceeds 0.12 QALYs/year (eg, 0.81 QALYs gained/year from endoAVF compared with base-case sAVF 0.69 QALYs/year), the endoAVF maturation rate is >90% (base case 78%), or the sAVF maturation rate is <65% (base case 78%). Probabilistic sensitivity analysis demonstrated that sAVF remained the optimal strategy in 71% of iterations.

CONCLUSIONS

EndoAVF is not cost effective compared with sAVF when modeling 5-year outcomes. The main driver of sAVF remaining cost effective is the four times higher up-front cost for endoAVF creation, as well as a relatively low additional increase in quality of life for endoAVF. It will be important to establish how the endoAVF learning curve contributes to upfront costs and, given the annual cost attributed to vascular access nationally, a randomized controlled trial is warranted.

Sex disparities in hemodialysis access outcomes: A systematic review

The goal of this systematic review was to collate and summarize the current literature on hemodialysis access outcomes in females, identify differences between females and men, and provide a foundation for future research. A systematic review of the English-language literature was conducted by searching PubMed and Google Scholar for the following terms: "sex," "hemodialysis access," "arteriovenous fistula," "arteriovenous graft," and "dialysis catheter." Reference lists from the resulting articles were also evaluated to ensure that any and all relevant primary sources were identified. Studies were then screened by two independent reviewers for inclusion. Of 967 total studies, 53 ultimately met inclusion criteria. Females have lower maturation rates; have decreased rates of primary, primary-assisted, and secondary patency; require more procedures per capita to achieve maturation and to maintain fistula patency; are more likely to receive dialysis via an arteriovenous graft or central venous catheter; and require a longer time and potentially more assistive invasive interventions to achieve a mature fistula. Our findings emphasize the urgent need for further research to evaluate and address the causes of these disparities. Discussion with patients undergoing hemodialysis should include these findings to improve patient education, expectations, satisfaction, and outcomes.

Systematic review and meta-analysis: Efficacy and safety of balloon angioplasty in salvaging non-matured arteriovenous fistulas

This study aimed to evaluate the clinical and technical success rates achieved after performing balloon-assisted maturation (BAM) for non-matured arteriovenous fistula (AVF). For this, a systematic review and meta-analysis were conducted by searching PubMed and Scopus databases. Studies regarding AVFs not suitable for use based on clinical examination or ultrasound criteria and BAM use for correcting the underlying stenotic lesion were eligible for inclusion in the meta-analysis. Accordingly, 13 studies with 1427 patients with non-matured AVF who underwent BAM were included. The pooled random effect for the clinical success rate was 90% (95% CI, 86%-93%), and that for the technical success rate was 97% (95% CI, 94%-99%). Complications after BAM were reported in 1.7%-41% of the patients. Complications included venous ruptures, wall hematomas, and puncture site hematomas. Early-BAM group had better clinical success rates. BAM is an effective intervention for salvaging non-matured AVF. The procedure is safe and feasible, and high clinical and technical success rates can be achieved. The complications were also manageable without serious sequelae.

The feasibility and efficiency for constructing arteriovenous fistula with <2 mm vein-a systematic review and meta-analysis

Background

Autogenous arteriovenous fistula (AVF) is an efficient hemodialysis access for patients with end-stage kidney disease (ESKD). The specific threshold of vein diameter still not reached a consensus.

Method

We conducted a comprehensive search in PubMed, Embase, and Web of Science databases for articles which comparing the treatment outcomes of AVF with 2 mm as vein diameter threshold. Fixed and random effect model were used for synthesis of results. Subgroup analysis was designed to assess the risk of bias.

Result

Eight high-quality articles were included finally. Among a total of 1,075 patients (675 males and 400 females), 227 and 809 patients possessed <2 mm and ≥2 mm vein respectively. Apart from gender and coronary artery disease (P < 0.05), there was no significant difference in age, diabetes, hypertension or radial artery between maturation and non-maturation groups. The functional maturation rate was lower in patients with <2 mm vein according to fixed effect model [OR = 0.19, 95% CI (0.12, 0.30), P < 0.01]. There was no significant difference in primary [OR = 0.63, 95% CI (0.12, 3.25), P = 0.58] or cumulative patency rates [OR = 0.40, 95% CI (0.13, 1.19), P = 0.10].

Conclusion

Vein diameter less than 2 mm has a negative impact on the functional maturation rate of AVF, while it does not affect the primary and cumulative patency rates (12 months).

Options for Dialysis and Vascular Access Creation

End-stage kidney disease (ESKD) affects nearly 800,000 patients in the United States. The choice of peritoneal dialysis (PD) versus hemodialysis (HD) should be patient centric. An ESKD Life-Plan is crucial with the goal of creating the right access, for the right patient, at the right time, for the right reason. Complex access should be considered when straightforward access options have been exhausted. Evolving techniques such as percutaneous access for HD and PD should be further investigated. Shared decision-making and palliative care is an essential part of the care of patients with CKD and ESKD..

The feasibility of small-caliber veins for autogenous arteriovenous fistula creation: A single-center retrospective study

Objective

Autogenous arteriovenous fistula (AVF) is recommended as the first choice for hemodialysis vascular access. A small-caliber vein is one of the independent risk factors for AVF maturation and patency. However, the specific threshold is still unclear, making it difficult to accurately determine whether these vessels are suitable for AVF creation.

Design

This is a single-center retrospective study.

Method

Patients who underwent AVF creation in our medical center between January 2020 and September 2022 and satisfied the eligibility criteria were included in this retrospective study. Logistic regression analysis was performed to identify risk factors for functional maturation and additional intervention. The optimal cutoff value was determined based on the receiver operating curve (ROC) and the Youden index. Kaplan-Meier analysis was utilized in further patency rate comparisons.

Result

A total of 125 forearm AVFs were created in 121 patients with end-stage renal disease (ESRD). The mean age was 53.88 ± 15.10  years. Preoperative vascular Doppler ultrasound (DUS) was conducted and recorded in 106 cases (84.80%). The mean targeted artery and vein diameters were 2.17 ± 0.54 and 1.71 ± 0.75  mm, respectively. Small-caliber vein is the risk factor for functional maturation failure (OR = 0.256, 95%CI [0.06-0.75], p = 0.033) and additional intervention (OR = 0.306, 95% CI [0.09-0.78], p = 0.031). The optimal cutoff value is 1.35  mm (augmented) when specificity and sensitivity reach 80 and 63.7%, respectively. The AVFs with a vein diameter of more than 1.35 mm (augmented) showed higher patency rates (p < 0.01).

Conclusion

After comprehensive DUS evaluation, intraoperative hydrodilation, postoperative active exercise and intensive DUS detection, and application of balloon-assisted maturation, if necessary, using a vein more than 1.35 mm (augmented), could achieve satisfactory functional maturation and postoperative patency in AVF formation.

Does the balloon-assisted maturation procedure offer comparable results for AVF created with a smaller vein?

BACKGROUND

Traditionally, a venous diameter of less than 3 mm was not considered for creation of AVF. Some studies have reported smaller venous size could be used for operation. AVF created with a smaller vein may have a lower maturation rate. Currently, percutaneous angioplasty is also used to enhance the maturation of AVF. This study aimed to establish whether the BAM procedure could offer comparable results for AVF created with a smaller vein.

METHODS

From January 2016 to July 2021, 290 patients who received native AVF operation were enrolled in this study. All of the preoperative venous sizes were measured by Duplex ultrasonography under tourniquet enhancement. The study cohort was categorized into two groups based on the pre-operative venous diameter: smaller vein group (SVG, 2.5 < size < 3 mm, 53.1%) and normal vein group (NVG, size ⩾ 3 mm, 46.9%).

RESULTS

The mean age was 64 ± 12.9 years, and 58.6% of patients were male. Hypertension and DM were the most common comorbidities. Most patients underwent operation of radio-cephalic fistula (71.4%). The overall primary maturation rate was 79%. The primary maturation rate was significantly higher in the NVG (86% vs 72.7%, p = 0.009). However, after the BAM procedure, the secondary maturation rate was similar in both groups (94.1% vs 90.3%, p = 0.319).

CONCLUSIONS

According to our study, the BAM procedure can significantly increase the maturation rate, and the secondary maturation rate was similar in both groups. Thus, more patients can be given the opportunity to undergo creation of an AVF for long-term hemodialysis.

Intraoperative vascular mapping improves patient eligibility for arteriovenous fistula creation

BACKGROUND

We assessed the utility of intraoperative vein mapping performed by the operating surgeon for evaluating vessel suitability for arteriovenous fistula (AVF) creation.

METHODS

In a retrospective review of 222 AVFs, vein diameter measurements were compared between intraoperative and preoperative mapping in the same anatomical location. AVF creation was based on intraoperative vein diameter ≥2 mm, using a distal to proximal and superficial veins first approach. Potential selection of access type based on preoperative findings alone was analyzed.

RESULTS

The mean diameter of the veins used for AVF creation measured 3.6 ± 0.8 mm on intraoperative duplex versus 2.5 ± 0.9 mm when the same veins were measured on preoperative duplex. Based on preoperative mapping alone, 23% of patients would have received a more proximal AVF and 5% would have needed a graft. AVFs created more distally based on intraoperative findings had similar maturation rates compared to the rest of the cohort, 79% versus 84% (p = 0.2).

CONCLUSIONS

Intraoperative vein mapping can be used to evaluate vessel suitability for AVF and compared to pre-operative vein mapping may increase the eligibility of distal veins for fistula creation while reducing the need for AV grafts.

Salvage of Suboptimal or Occluded Arteriovenous Fistulas Using a 4 French System From the Radial Artery for Initial Balloon Angioplasty Maturations

Introduction End-stage renal disease (ESRD) is a condition that has seen a large increase in prevalence in recent decades. Paralleling this increase in prevalence is the increasing number of patients requiring vascular access for hemodialysis. Arteriovenous fistulas (AVFs) and arteriovenous grafts (AVGs) are considered the procedures of choice for hemodialysis access. However, due to the suboptimal venous anatomy (<2 mm diameter, sclerotic vascular walls) and chronic medical conditions (diabetes mellitus) seen in many ESRD patients, successful AVF creation and maturation is not always possible using standard procedures. In this study, we performed primary balloon angioplasty (PBA) at the time of AVF creation with subsequent balloon angioplasty maturation (BAM) procedures in a group of patients with a large proportion of diabetes and suboptimal venous anatomy. The purpose of this study was to compare the assisted patency and survival rates in patients with suboptimal veins used to create AVFs to patients with standard vein AVFs and AVGs.  Methods Over a nine-year period, PBA during AVF creation was performed 682 times. Of these, 551 AVFs were matured in optimally sized veins using standard BAM procedures, and 131 AVFs were matured in suboptimal veins utilizing a modified approach. In the subset of patients with suboptimal venous anatomy, we performed the initial BAM procedure via the radial artery utilizing a 4 French system. Additionally, routine clinical surveillance was scheduled throughout the study period for all patients. Suboptimal veins included small (<2 mm diameter), sclerotic, accessory, or recanalized veins. During the study period, 69 AVGs were created and matured using standard graft-gram procedures. A Kaplan-Meier analysis of survival and assisted patency rates comparing the three groups were calculated utilizing data from a retrospective database and medical records. A hazard ratio and a log-rank test were calculated to assess statistical significance. Results The mean time of follow-up for all three groups (n=703) was 43.2 months. Among patients requiring hemodialysis access in the study, the fistula creation rate was 90.8%. Patients with suitable venous anatomy who underwent AVF creation with PBA and standard BAM procedures experienced higher primary assisted patency rates relative to the suboptimal vein AVF and AVG groups (p<0.0001). No difference was seen between the suboptimal vein AVF and AVG groups. Patient survival and the percentage of diabetics were comparable amongst all three groups. Conclusion Using our approach, we were able to achieve a high AVF creation rate amongst a group of patients with a large proportion of suboptimal veins and diabetes. Despite not performing as well as standard vein AVFs in regards to primary assisted patency, the patients with suboptimal vein AVFs experienced similar patency and survival rates as compared to patients receiving AVGs. This new approach enhances the ability to create AVFs in patients who would otherwise not be amenable to fistulas and may contribute to reduced complication risk and improved overall survival.