Duplex-guided balloon angioplasty of failing or nonmaturing arterio-venous fistulae for hemodialysis: A new office-based procedure

Duplex ultrasound-guided angioplasty of hemodialysis vascular access

OBJECTIVE

Duplex ultrasound-guided angioplasty (DA) for hemodialysis vascular accesses remains questionable regarding its feasibility and safety. Minor complications (requiring no more treatment than nominal therapy) might be over-reported. Our hypothesis is that this procedure has no significant differences between observed rates and the recommended threshold of main outcomes of the procedure defined by the standards of arteriovenous fistulas (AVF) angioplasty.

METHODS

In a single-center retrospective study, 298 DA performed on 141 patients from 2015 to 2019 were analyzed. Occluded AVF or concomitant use of radiographic guidance were excluded. Duplex ultrasound parameters were collected up to 1 month before, at the end of angioplasty, and on day 30 after the procedure. Complications were registered, and patency rates were studied at 24 months of follow-up.

RESULTS

Anatomical success was achieved in 142 procedures (47.7%), clinical success in 284 (95.3%), and hemodynamic success in 283 (95.0%). Major complications-requiring at least a specific therapy-were reported in 8 procedures (2.7%) and minor complications-requiring no adjunctive therapy-in 157 (52.7%). At 24 months, overall postintervention primary patency was 34.0%, primary-assisted patency 87.4%, and secondary patency 92.5%. There were no significant differences of patency rates between groups with or without minor complications (P value for primary patency, 0.08; primary-assisted patency, 0.08; secondary patency, 0.23) or 30% residual stenosis (P value for primary patency, 0.82; primary-assisted patency, 0.46; secondary patency: 0.63). Duplex parameters further improved at postoperative day 30 after angioplasty.

CONCLUSIONS

DA of AVF is feasible, safe-despite over-reported minor complications having no impact on postintervention patency rates-and efficient. A minor complication can be seen as an event without bad or good consequences. Anatomical definition of success does not fit on DA for hemodialysis vascular access. Further studies are required to define the duplex parameter threshold for efficacy.

X-ray-guided and ultrasound-guided percutaneous transluminal angioplasty to treat arteriovenous fistula dysfunction in hemodialysis patients: A retrospective controlled study

PURPOSE

To compare the safety and efficacy of X-ray-guided and ultrasound-guided percutaneous transluminal angioplasty in treating arteriovenous fistula dysfunction.

MATERIALS AND METHODS

Data for 219 patients with arteriovenous fistula dysfunction between January 2016 and December 2018 were retrospectively analyzed. The primary endpoints were technical success, clinical success, and primary patency rates. The secondary endpoints were complications and secondary patency rates. Procedure outcomes and both endpoints were evaluated by propensity score analysis.

RESULTS

After the propensity score matching, 73 matched pairs of cases were created with 34 pairs of autogenous arteriovenous fistula cases and 39 pairs of prosthetic arteriovenous graft cases. There was no significant difference between the X-ray-guided and ultrasound-guided group, respectively, regarding the technical success rate (84.9% vs 87.7%, p = 0.630), clinical success rate (98.6% vs 97.3%, p = 0.999), and complications (10.9% vs 5.5%, p = 0.228). Although the 6- and 12-month secondary patency rates for the dialysis access between the two groups had significant difference (p < 0.05), there was no significant difference in primary and secondary patency curves between the two groups (p > 0.05).

CONCLUSION

The overall efficacy of ultrasound-guided versus X-ray-guided percutaneous transluminal angioplasty in treating arteriovenous fistula dysfunction might be comparable.

Clinical Aspects of Dialysis Interventions: Physical and Sonographic Findings

Physical examination (PE) of arteriovenous access remains of high clinical value and continues to be recommended by leading societies and guidelines. PE is easy to learn and perform. Once learned, examiners can provide a comprehensive arteriovenous (AV) access examination in 20 to 30 seconds. Therefore, we continue to advocate that AV access PE should be part of the training for all dialysis care providers. Similarly, ultrasound can provide important AV access evaluation and provide key information. It is relatively cheap and can be readily available at the bed side. Additionally, it is well accepted by patients, as it is not expected to be associated with pain or discomfort during the examination. We present in this review the key components of PE, signs and symptoms of AV access dysfunction, and the role of ultrasound in AV access evaluation as a complementary tool to PE.

Ultrasound-guided percutaneous transluminal angioplasty for the treatment of cephalic arch stenosis in hemodialysis arteriovenous fistulas

OBJECTIVES

Cephalic arch stenosis (CAS) is a common cause that leads to the failure of hemodialysis arteriovenous fistulas (AVFs). Patients with CAS are primarily treated with fluoroscopy-guided angioplasty. Here, seven patients with de novo cephalic arch stenosis who underwent office-based UG-PTA were.

METHODS

Retrospectively analyzed the total of 321 patients with AVF dysfunction in the nephrology departmnet between July 2017 and October 2018. Among them, seven patients with de novo CAS were included in this study and followed up every 2 months for more than a year.

RESULTS

No significant complications were seen from the operations, and the primary patency rates at 6 and 12 months were found to be 100% and 42.8%, respectively.

CONCLUSIONS

The office-based UG-PTA is probably safe, effective, and feasible in the management of CAS and can be used as a substitute for fluoroscopy-guided PTA.

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.

Ultrasound guided interventional procedures on arteriovenous fistulae

Autogenous (AVF) and prosthetic (AVG) arteriovenous fistulas are the vascular accesses (VA) of choice for hemodialysis thanks to their improved patency, reduced costs, and lower rate of infections relative to catheters.

In an effort to maximize the number of primary AVF and AVG, shorten maturation times for AVF, and reduce the number of indwelling catheters, several new techniques have been developed within the context of an overall program designed to optimize access care.

This approach includes: (a) Primary Intraoperative Balloon Angioplasty on the vessels selected for AV creation whether small-sized or altered by pre-existing lesions; (b) Percutaneous Transluminal Angioplasty (PTA) on AVF and AVG stenosis, performed under ultrasonographic (UG) or fluoroscopic guide (FG).

We report the experience of two Center in performing the above mentioned procedures on even complex VA. The wise adoption of these techniques may avail to meet the stringent demands for reliable VA placement as defined by KDOQI and, thereby, expand the duration and quality of life for hemodialysis patients.

Efficacy of ultrasound-guided percutaneous transluminal angioplasty for arteriovenous fistula stenosis or occlusion at juxta-anastomosis: A 3-year follow-up cohort study

OBJECTIVE

Arteriovenous fistula (AVF) is the preferred access for hemodialysis. Percutaneous transluminal angioplasty (PTA) has become a choice for AVF stenosis, and ultrasound has been used in PTA more frequently.

METHODS

This single-center retrospective cohort study analyzed 129 patients who underwent PTA in the First Affiliated Hospital of Chongqing Medical University from January 2016 to December 2016. Angioplasty was performed using a noncompliant high-pressure balloon. The process was visualized by duplex scan. Our inclusion criteria were as follows: (1) stenoses or occlusions were located at the juxta-anastomosis site: the first 5 cm of the vein distal to the anastomosis; (2) stenosis was confirmed with the following conditions: (a) flow rates are <500 mL/min in the brachial artery and <200 mL/min in the fistula during dialysis, and (b) the stenosis diameter is <1.7 mm. We used the Kaplan-Meier curve to show the postintervention primary and secondary patency rates of patients with stenosis and occlusion.

RESULTS

Altogether, 129 patients with 76 males were analyzed. Moreover, 104 have AVFs on the left arm, and only one patient had an ulnar-basilic AVF, whereas others had a radial-cephalic AVF. The postintervention primary patency rates are better in occlusion cases (P < .05), whereas secondary patency rates have no difference. The postintervention primary patency rates are better in patients without diabetes mellitus (P < .05), whereas the secondary patency rates had no difference.

CONCLUSIONS

For juxta-anastomosis site stenosis or occlusion, PTA can be used to obtain satisfactory results.

Balloon-assisted maturation of autogenous arteriovenous fistulae: A randomized controlled prospective study

BACKGROUND

Current guidelines recommend referral of patient with renal failure for access creation 6 months before planned dialysis. There is a growing cohort of patients that require long-term hemodialysis without adequate preparation. Temporary dialysis catheters and rapid access arteriovenous grafts (AVG) are far from being an ideal solution in this scenario. In an effort to expedite maturation of autogenous arteriovenous fistulae (AVF), balloon-assisted maturation (BAM) was advised by some authors. This technique still lacks the support of high-level evidence studies. We investigated the ability of intra-operative BAM to induce early functional maturation of AVFs.

METHODS

This is a prospective randomized controlled study conducted in a tertiary referral center, with a catchment area of more than 15 million population. Cases were divided into two groups; Group (A), where BAM technique was performed, while in the control group (B), the standard technique was used (NO BAM) for creation of AVFs.

RESULTS

Between June 2017 and May 2019, 300 cases were recruited from a total of 648 primary AVF creation instances. Patients' age ranged from 19 to 89 (mean 51.17 ±SD 15.5) years. Group A (BAM) included 52.3% (n = 157) AVFs, while Group B included 47.7% (n = 143) AVFs. The average maturation time was 3.7 weeks (SD ± 1.3, 95% CI 3.55-3.95) and 5.91 weeks (SD ± 2.2, 95% CI 5.55-6.26) for both groups, respectively (p = 0.0001). 78.3% of the AVFs that underwent BAM showed early maturation within 2-4 weeks vs 32.2% only in the NO BAM group (p = 0.002). Successful functional maturation was higher among cases of the BAM group (93%), compared to the NO BAM group (77%) (p = 0.001). Complication rates were 9.6% and 4.9% in the two groups, respectively (p = 0.042).

CONCLUSION

BAM can play a pivotal role in helping the dialysis society meet the goals of the Fistula First Initiative, keeping in mind that this comes with an increased risk of complications. BAM should be considered only when unplanned early access to long-term dialysis is required.

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

BACKGROUND

Traditional practice suggests the abandonment of veins smaller than 3 mm in diameter for arteriovenous fistula (AVF) creation because of a low rate of maturation. This study aims to show that with balloon-assisted maturation (BAM), undersized veins can be used to create functional AVFs with a high rate of success.

METHODS

All patients who underwent AVF creation between 2014 and 2018 at a tertiary academic medical center were retrospectively reviewed. The patients without preoperative vein mapping, those who failed to follow-up, and the patients who were not on dialysis were excluded. A fistula was considered to be mature if it was successfully cannulated for dialysis. A total of 596 patients were identified for analysis. The cohort was divided into the small-vein group (SVG, <2.5 mm) and large-vein group (LVG, ≥2.5 mm) based on preoperative vein size. Categorical variables were analyzed with the chi-squared test for their association with maturation status. Continuous variables were analyzed with the Wilcoxon rank sum test. A P-value less than 0.05 was considered significant.

RESULTS

In the study cohort, 61.9% of the patients were male, with an average age of 62.8 ± 13.7 years, and an average preoperative vein size of 2.9 ± 1.1 mm. With similar demographic distribution, the participants in the SVG (n = 216) had significantly smaller preoperative vein size of 1.9 ± 0.4 mm than the patients in the LVG (n = 380), 3.5 ± 0.8 mm (P = 0.001). There were significantly more radio-cephalic AVFs created in the SVG (77.8% versus 48.7%, P < 0.0001). The overall maturation rate was 83.1% (n = 495), 219 fistulas (36.7%) matured primarily and 276 (46.3%) required interventions. Ninety-one percent of the patients required only 1 or 2 BAMs to achieve maturation. The SVG achieved a maturation rate of 75.9% as compared with 87.1% in the LVG (P = 0.002). A significantly higher number of patients in the SVG required BAM for maturation as compared with the LVG (67.7% versus 49.9%, P = 0.0002); however, there was no difference in the average number of BAMs required for fistula maturation between the groups (1.5 ± 0.8 for the SVG vs. 1.4 ± 0.7 for the LVG). In multivariable logistic regression analysis, vein size ≥2.5 mm (odds ratio (OR) = 2.11, confidence interval (CI): 1.36-3.27, P = 0.0009) and male sex (OR = 2.30, CI: 1.49-3.57, P = 0.0002) were independent predictors of maturation.

CONCLUSIONS

Small veins can be used for AVF creation with lower but still favorable maturation rates using BAM interventions, especially in male patients. This practice can increase the creation of autogenous dialysis access and potentially reduce complications related to prosthetic dialysis access.

The Nephrologist as an Ultrasonographer

Ultrasonography is increasingly being used in the practice of nephrology, whether it is for diagnosis or management of acute or chronic kidney dysfunction, until progression to end-stage kidney disease, including preoperative assessment, access placement, and diagnosis and management of dysfunctional hemodialysis access. Point-of-care ultrasounds are also being used by nephrologists to help manage volume status, especially in patients admitted to the intensive care units, and more recently, for guiding fluid removal in the outpatient dialysis units. Fundamental knowledge of sonography has become invaluable to the nephrologist, and performance and interpretation of ultrasound has now become an essential tool for practicing nephrologists to provide patient-centered care, maximize efficiency, and minimize fragmentation of care. This review will address the growing role of ultrasonography in the management of a patient with CKD from the point of initial contact with the nephrologist throughout the spectrum of kidney disease and its consequences.

Ultrasound-guided angioplasty of dialysis fistulas in renal transplant patients

Introduction

Percutaneous endovascular angioplasty has become the treatment of choice for dialysis fistula stenosis. The ultrasound-guided endovascular procedure is used in patients with severe renal impairment and advanced renal transplant failure, when the need for nephrotoxic contrast administration in standard angioplasty may worsen renal function.

Aim

To evaluate endovascular angioplasty guided by ultrasound for dialysis fistula stenosis in renal transplant patients with severe graft insufficiency.

Material and methods

We compared ultrasound (US)-guided angioplasty, performed in patients after renal transplantation, with standard contrast angioplasty performed in dialysis patients. We treated 10 kidney allograft recipients (9 kidneys and 1 kidney-pancreas) with significantly compromised renal transplant function and significant stenosis in dialysis fistulas, as detected during US examination. Patients were qualified for percutaneous angioplasty under US guidance. The mean period from transplantation was 32.7 months (5–100 months). Results of their treatment were compared to the control group of 20 end-stage renal disease patients with dialysis fistula stenosis treated by angioplasty under standard contrast visualization.

Results

The immediate effectiveness of the angioplasty was 100% in both groups. No early complications of angioplasty or problems with the guidewire crossing the stenosis were observed. Twelve months of primary patency was observed in 80% and 45% in the US-guided and control groups, respectively.

Conclusions

The US-guided endovascular procedure is an effective and safe method of treating dialysis fistula stenosis in patients with impaired renal transplant function.

Ultrasound in dialysis access: Opportunities and challenges

Sonography is increasingly being used by nephrologists and the field of dialysis access is no exception. Advances in technology have allowed the addition of this universally available, portable, non-invasive tool to the nephrologist's armamentarium, which provides information on both morphology and physiology without the need for contrast or radiation. Ultrasound may be used across the spectrum of dialysis access, including central venous catheter placements, vascular mapping, regional anesthesia, creation, maintenance and assessment of hemodialysis access as well as assessment of the abdominal wall and peritoneal dialysis catheter placements. However, the lack of exposure in most training programs limits incorporation of routine use of ultrasounds in nephrology practice. As our specialty embarks on the ultrasound revolution, a two-pronged approach is essential to provide ample training opportunities while ensuring establishment of basic standards for training and competency.

Ultrasound-guided Angioplasty of Arteriovenous Fistulas for Hemodialysis: Benefits and Limitations

BACKGROUND

Ultrasound-guided percutaneous angioplasty of arteriovenous fistulas (AVFs) makes it possible to avoid contrast agents and X-rays, to optimize the puncture site and to locate some stenoses on the fistulography, but is it really useful? Our objective is to report the results of our experience.

METHODS

Between November 2012 and November 2017, all the patients treated according to this method in our center were collected retrospectively. The surgical indications were an insufficient maturation of the AVF, an increase in the venous pressure, an inadequate outflow, difficulties in puncture, a prolonged bleeding time, a flow drop, or an aneurysmal evolution.

RESULTS

During this period, 50 patients had 72 ultrasound-guided angioplasties, 64 on native AVFs (88.9%) and 8 on prosthetic AVFs (11.1%). The technical success rate was 100%. The average preoperative flow of AVFs was 506.8 ± 302.2 vs. 955.9 ± 371.4 mL/min after angioplasty. The mean duration of follow-up was 13.4 ± 12.9 months. The cumulative rates of primary, assisted primary, and secondary patency were 43.5%, 68.8%, 81.5% at 1 year and 31.7%, 63.9%, 76.8% at 2 years, respectively.

CONCLUSIONS

AVF angioplasty under ultrasound guidance only is feasible, effective, and represents an interesting alternative. A controlled study comparing ultrasound guidance with angioplasties performed under conventional angiographic guidance as the reference technique would better clarify the value of this technique.

Vascular access surgery can be safely performed in an ambulatory setting

INTRODUCTION:

Ambulatory surgery is associated with lower costs, but there is lack of evidence of the safety for ambulatory vascular access surgery. The objective of this study is to substantiate the safety and effectiveness of performing vascular access surgery in an ambulatory setting.

METHODS:

A review of our prospectively maintained database including all vascular access open surgeries (creations and repairs) performed by our Vascular Access Unit between 2013 and 2017 was compiled. Patient comorbidities, surgery details, hospital admission conditions, and 1-week and 1-month follow-up patency and complications (death, infection, bleeding, and readmission/reintervention) were scrutinized.

RESULTS:

In the last 5 years, 1414 vascular access procedures were performed (67.8% access creations, 32.2% previous access repairs) in 1012 patients. Most surgeries were performed under local anesthesia (59.2%) or axillary plexus block (38.4%) and mainly in an ambulatory setting, without overnight hospital stays (90.9%). During the first postoperative week follow-up, 9 cases (0.6%) needed readmission or reintervention; significant infection materialized in 11 (0.8%) and 10 cases (0.7%) showed noteworthy hematoma or bleeding, only three (0.2%) requiring reintervention. The primary composite endpoint of 24-h death and 1 week readmission, reintervention, infection, or bleeding was 1.9% (27 cases); 1-month access failure was 6.2%. After univariate analysis, ambulatory settings were not related to higher rates of complications or readmissions.

CONCLUSION:

Arteriovenous access surgery can be safely performed in an ambulatory setting, in spite of complex cases, comorbidities, or the increasing implementation of axillary plexus blocks. Surgical results and patency are good, and complications necessitating readmission remain very low.

Point-of-care ultrasound in the practice of nephrology

Sonography is increasingly being performed by clinicians and has applications throughout the spectrum of nephrology, including acute and chronic renal failure, urinary obstruction, cystic disease, pain, hematuria, transplantation, kidney biopsy, temporary and permanent vascular access, and assessment of fluid status. The skill is relatively easily acquired, expedites patient care, and enhances the practice of nephrology. However, the lack of exposure in most training programs remains a major obstacle.

A novel technique for duplex-guided office-based interventions for patients with acute arteriovenous fistula occlusion

OBJECTIVE

The purpose of the study was to aggressively salvage acutely occluded arteriovenous fistulas (AVFs) using duplex imaging as the sole imaging modality for percutaneous transluminal angioplasty of acutely thrombosed AVF.

METHODS

Over a period of 12 months, 14 patients with acute thrombosis of their AVFs underwent 18 procedures in a single center for AVF salvage. All 14 patients presented with chronic renal failure, and six were diabetic. All patients were treated under duplex guidance alone. Treatment included simple balloon dilation and maceration (group A; n =10 procedures [56%]) for subacute thrombosis or pharmacomechanical thrombectomy (group B; n = 8 procedures [44%]) for more hypoechoic thrombus. A successful procedure was defined as immediate restoration of flow through the AVF.

RESULTS

Of the 18 procedures, 13 (72%) were successful. Of the 14 patients, thrombus was located at the perianastomotic AVF in 6 (43%), proximal-mid AVF in 6 (43%), mid AVF in 1 (7%), and distal AVF in 1 (7%). From group A, six (60%) were successful. From group B, seven (88%) were successful. Among the unsuccessful procedures, one group B patient was hypercoagulable (polycythemia vera). Of the 18 procedures, 16 (89%) were treated within 2 weeks from when duplex revealed the presence of thrombus. Early rethrombosis (<1-month patency) occurred in three cases (17%), and these patients received new fistulas. Full restoration of the fistula flow was established in 14 cases (78%). Of these 14 patients, 8 (57%) are currently on hemodialysis via fistula, 3 patients (21%) had newly placed fistulas after failed interventions, 2 patients (14%) are not on dialysis yet, and 1 patient (7%) with polycythemia vera disorder is on dialysis via a Tesio catheter (MedComp, Harleysville, Pa).

CONCLUSIONS

The sole use of duplex ultrasound imaging to salvage acutely occluded AVFs using percutaneous transluminal angioplasty is a safe and effective alternative to traditional treatment of thrombosed failing/maturing AVF.

Endovascular treatment to boost AV fistula maturation

Impaired fistula maturation is associated with puncture-related complications, insufficient dialysis and potential permanent access failure. Non-maturation is frequently initiated by stenotic vascular access vessels comprising the outflow veins, the arteriovenous anastomosis and infrequently the inflow artery. Further findings in maturation protraction are central venous stenoses or accessory outflow veins. Depending on the underlying pathology, several endovascular approaches to boost fistula maturation are possible. To date standard balloon angioplasty remains the primary proven treatment option.

Clinical experience with ultrasound guided angioplasty for vascular access

Background

The use of ultrasound guided percutaneous transluminal angioplasty (UG-PTA), which use ultrasound as an imaging modality, is an evolving strategy. But, in Korea, this method is rarely used. We report our experiences with UG-PTA with respect to technical success rates and complication rates compared to conventional PTA (C-PTA), performed between 2010 and 2015 at Samsung Changwon Hospital, Korea.

Methods

In our series, 53 cases of UG-PTA and 90 cases of C-PTA were reviewed, respectively. Cases of central vein stenosis, cephalic arch stenosis, arterial stenosis and thrombosis were excluded. However, cases of juxta-anastomotic stenosis and outflow vein stenosis were included.

Results

Technical success was achieved in 96.2% (51 of 53) of cases in the UG-PTA group and in 93.3% (84 of 90) of cases in the C-PTA group, respectively (P = 0.710). Technical failure was experienced in a total 8 cases (UG-PTA group: 2/53, 3.8%; C-PTA group: 6/90, 6.7%). No differences were observed in complications.

Conclusion

Duplex ultrasound-guided angioplasty for dialysis access in the outpatient setting is feasible, safe, and effective for peripheral venous stenotic lesions. It offers many advantages over conventional angiographic procedures, and, in the future, it has great potential to play a significant role in the management of these challenging patients.

Contrast-enhanced US-guided Interventions: Improving Success Rate and Avoiding Complications Using US Contrast Agents

Ultrasonography (US) is an established modality for intervention. The introduction of microbubble US contrast agents (UCAs) has the potential to further improve US imaging for intervention. According to licensing, UCAs are currently approved for clinical use in restricted situations, but many additional indications have become accepted as having clinical value. The use of UCAs has been shown to be safe, and there is no risk of renal toxic effects, unlike with iodinated or gadolinium contrast medium. Broadly speaking, UCAs can be injected into the bloodstream (intravascular use) or instilled into almost any accessible body cavity (endocavitary use), either in isolation or synchronously. In microvascular applications, contrast-enhanced US (CEUS) enhances delineation of necrotic areas and the vascularized target to improve real-time targeting. The ability of CEUS to allow true assessment of vascularity has also been used in follow-up of devascularizing intervention. In macrovascular applications, real-time angiographic images can be obtained with CEUS without nephrotoxic effects or radiation. In endocavitary applications, CEUS can achieve imaging similar to that of iodinated contrast medium-based fluoroscopy; follow-up to intervention (eg, tubography and nephrostography) can be performed at the bedside, which may be advantageous. The use of UCAs is a natural progression in US-guided intervention. The aim of this article is to describe the indications, contraindications, and techniques of using UCAs as an adjunctive tool for US-guided interventional procedures to facilitate effective treatment, improve complication management, and increase the overall success of interventional procedures. Online supplemental material is available for this article. ^©RSNA, 2016.

Ultrasound-guided angioplasty for treatment of peripheral stenosis of arteriovenous fistula - a single-center experience

PURPOSE

In patients with end-stage renal disease, arteriovenous fistulas (AVFs) are the access of choice for hemodialysis but are often complicated by stenosis. We present single-center experience of 78 ultrasound-guided angioplasty procedures for treating peripheral stenoses of AVFs.

METHODS

Between January 2013 and November 2015, 78 angioplasties were performed under ultrasound guidance in 53 patients with end-stage renal disease who were referred from dialysis centers with low flow rate, difficult cannulation, increased cannulation site bleeding, immature or thrombosed AVF. Angioplasties were carried out in the presence of a structural lesion in the AVF resulting in at least 50% reduction in vein diameter with a blood flow of &lt;250 mL/min or a peak systolic velocity &gt;300 cm/s. Clinical success, anatomical success and post-intervention primary and secondary patency rates at 6, 12, 18 and 24 months were studied.

RESULTS

In 49/53 patients (92.4%), 74 angioplasty procedures were successfully performed, whereas 4/53 patients (7.6%) had primary failure. A total of 35/49 patients (71.4%) underwent single angioplasty procedure whereas 14/49 patients (28.6%) underwent multiple angioplasty procedures. Post-intervention primary patency rates at 6, 12, 18 and 24 months were 78.6%, 60.2%, 53.8% and 48.9%, respectively. Post-intervention secondary patency rates at 6, 12, 18 and 24 months were 100%, 100%, 95.4% and 89%, respectively. Clinical success and anatomical success was 94.8% and 89.7%, respectively.

CONCLUSIONS

Ultrasound-guided angioplasty is an effective method with good long-term outcomes in selected dialysis patients with peripheral stenosis of AVF.

The Clinical Efficacy of Balloon-Assisted Maturation of Autogenous Arteriovenous Fistulae

BACKGROUND

Delayed maturation of arteriovenous fistulae (AVF) among patients who require hemodialysis (HD) can lead to catheter sepsis with its resultant morbidity and mortality. Some have proposed that sequential balloon-assisted maturation (BAM) may accelerate the maturation times of these accesses. On the other hand, serial balloon angioplasty of normal vein may result in stenosis and delay maturation. Although the safety of BAM has been shown, direct comparison to nonmatured AVF has not been explored. Therefore, we conducted a retrospective analysis of our prospectively maintained vascular access database to compare the duration of period to AVF maturation between patients who received BAM and those who were not referred for BAM at our institution.

METHODS

Prospectively collected data over a 3-year period in 194 patients who underwent AVF creation at our institution were retrospectively analyzed. The duration to maturation of the AVF was determined by comparing the period between the creation of the fistula and the first successful cannulation of the fistula. Only patients on HD were included. Patients who underwent BAM or placement of AVF at an outside institution were excluded. Follow-up consisted reviewing of postoperative AVF duplex for patency, hospital and clinic databases, HD center databases, and telephone interviews.

RESULTS

Of the 194 patients who had AVF placement, 172 patients were on HD within 2 weeks of AVF placement, whereas 22 patients had AVF placed in anticipation of the need for HD. Of the 172 patients on HD within 2 weeks, 54 patients had BAM performed at our institution and 4 patients had BAM at an outside institution, whereas 114 patients were not referred for BAM. Thirty-three of these 114 patients were age and gender matched to compare to the patients who underwent BAM at our institution. At the time of this analysis, of the 54 patients who had BAM, 30 had functional AVF (19 men, 11 women; mean age, 62 years; range, 26-86 [standard deviation, SD ± 18] years). In the BAM group of functioning AVF, n = 30, the total number of procedures was 125 (range, 1-8, average 4). The overall average duration to maturation of the AVF was 119 days (SD ± 84 days) and 146 days (SD ± 157 days) P = 0.73, for BAM and non-BAM, respectively.

CONCLUSIONS

These preliminary data suggest the role of BAM did not decrease maturation times of AVF and that BAM warrants further scrutiny before further adoption.

Balloon-assisted maturation for arteriovenous fistula maturation failure: an early period experience

PURPOSE

Balloon-assisted maturation (BAM) is emerging as a salvage management for arteriovenous fistula maturation failure (AVF MF). However, BAM is a relatively new, yet controversial technique for AVF maturation. Therefore, we evaluated the effectiveness of BAM for AVF MF.

METHODS

Between January 2012 and December 2014, 249 AVFs were created. The total MF rate was 24.8%. But, only 110 AVFs were enrolled, including 74 brachiocephalic (BC) AVFs and 36 radiocephalic (RC) AVFs. The follow-up period was 12 months. Among those, there were 42 MFs (22 BC AVFs and 20 RC AVFs) and 68 maturation successes (MS) (52 BC AVFs and 16 RC AVFs). BAM was involved in MF group. We compared the clinical characteristics, AVF flows, and AVF flow ratios of MF and MS groups. Also, we evaluated the etiology, management, and result of MF.

RESULTS

There was no difference in clinical characteristics between MF and MS groups. In MF group, 39 balloon angioplasties (BAs) for 42 AVF MFs were performed. Number of BA was 1.45 ± 0.57 and duration of BA was 21.30 ± 21.24 weeks. BAM rate was 46.2%. For 1 year after AVF creation, AVF flows of MS group were significantly larger than those of MF group (P < 0.05) but there was no difference in AVF flow ratio between MF and MS groups (P > 0.05).

CONCLUSION

BA for AVF MF is a relatively applicable and effective modality. Although a large volume study is necessary, we suggest BAM is an effective salvage management for AVF MF.

The next frontier of office-based inferior vena cava filter placement

OBJECTIVE

There is an increasing number of procedures that traditionally were performed in the inpatient setting that are now becoming office-based procedures. These include peripheral endovascular procedures such as angiograms, angioplasties, dialysis access interventions, and treatment for venous insufficiency. We chose to evaluate the feasibility, safety of inferior vena cava (IVC) filter placement in the office-based setting.

METHODS

All procedures were performed using local anesthesia, and ultrasound guidance for puncture. All venograms were performed with manual injection of iodinated contrast. An IVC filter was placed in the cases (except one failure of placement) using fluoroscopy in the infrarenal position. Patients were observed in a recovery area and then discharged. Follow-up data were obtained through an interview, physical examination, and 24-hour postoperative phone call.

RESULTS

Over the course of 27 months, 29 Greenfield filters (Boston Scientific, Marlborough, Mass) and three Celect temporary filters (Cook, Bloomington, Ind) were placed in the infrarenal IVC for 18 women and 14 men, with an average age of 75.3 ± 15.6 years (range, 38-97 years). Twenty-four acute, 6 recent (<6 months ago) and three subacute lower extremity deep vein thromboses (DVTs) were identified. The indications for the procedure were patients with: DVT who were to undergo surgery (n = 6), acute large free-floating iliofemoral DVT (deemed high-risk for long-term anticoagulation) (n = 7), new DVT during anticoagulation therapy (n = 6), DVT with gastrointestinal bleeding (n = 4), DVT with hematuria (n = 2), recent DVT (which extended during full dose anticoagulation treatment) while undergoing a long flight (n = 1) (temporary filter placement), DVT with arm hematoma (n = 1), DVT with unsteady gait and history of falls (n = 2), DVT with nose bleeding (n = 1), DVT with dementia and inability to receive anticoagulation treatment (n = 1), DVT and receiving chemotherapy and with thrombocytopenia (n = 1), and DVT and refusal to take anticoagulation medication (n = 1). One patient had a failure to place a filter because of chronic IVC occlusion found on venogram. One patient with history of gastrointestinal bleeding, acute DVT, and atrial fibrillation suffered IVC filter thrombosis 1 month after the procedure. We attempted removal of the temporary filters in the hospital in two patients but failed to retrieve the filter in these two cases. We noted no insertion site DVT, extension of DVT, or pulmonary embolism.

CONCLUSIONS

Our preliminary experience suggests that placement of IVC filters for treatment of venous thrombotic events in an office-based facility is safe and efficacious with basic endovascular equipment. Long-term outcome cannot be determined at this point.

Organisation of a Radiological Vascular access Unit

An interventional vascular access unit is usually part of an interdisciplinary centre, including departments of nephrology, vascular surgery, angiology and interventional radiology. We present recommendations on quality control, equipment and diagnostic and interventional techniques for the treatment of vascular access insufficiency.

Ultrasound-guided angioplasty of dialysis fistula - technique description

Endovascular procedures are commonly used for treatment of vascular pathologies. These interventions are routinely performed under angiographic control. Angioplasty is increasingly more often used for correction of dialysis fistula – especially dilatation of stenosis. We describe the technique of dialysis fistula angioplasty under ultrasound control. Benefits of this procedure include lack of nephrotoxic contrast, what is especially important in chronic kidney disease patients in pre-dialysis period. Advantages of ultrasound guidance during dialysis fistula angioplasty lead to cause more and more frequent employment of this technique.

Reliability of ultrasound duplex for detection of hemodynamically significant stenosis in hemodialysis access

OBJECTIVE

This study aims to evaluate the accuracy of AVF and AVG duplex ultrasound (US) compared to angiographic findings in patients with suspected failing dialysis access.

MATERIALS AND METHODS

From July 2008 to December 2010, US was performed on 35 hemodialysis patients with 51 vascular accesses having clinical feature or dialysis parameter suspicious of access problem. Peak systolic velocity ratio of ≥2 was the criteria for diagnosing stenosis ≥50%. Fistulogram was performed in all these patients. Results of US and fistulogram were compared using Kappa and Receiver Operator Characteristic (ROC) analyses.

RESULTS

In 51 accesses (35 AVF, 16 AVG), US diagnosed significant stenosis in 45 accesses according to the criteria and angiogram confirmed 44 significant stenoses. In AVF lesions, Kappa was 0.533 with 93.3% sensitivity and 60% specificity for US whereas in AVG lesions, Kappa was 0.636 with 100% sensitivity and 50% specificity. Overall Kappa value of 0.56 meant fair to good agreement. ROC demonstrated area under the curve being 0.79 for all cases and was significant (p = 0.016). Using the ≥50% criteria for stenosis diagnosed by US yielded the best sensitivity (95.5%) and specificity (57.1%).

CONCLUSION

Duplex ultrasound study, using ≥50% criteria, is a sensitive tool for stenosis detection in patients with suspected failing AVF and AVG.

To BAM or not to BAM?: A closer look at balloon-assisted maturation

BACKGROUND

Balloon assisted maturation (BAM) is a recent, innovative, yet controversial method for developing autogenous arterio-venous fistulae (AVF), with little supportive data. Few retrospective studies have addressed the efficacy of BAM and cofactors affecting successful maturation. We conducted a retrospective analysis of our vascular access database to compare possible factors associated with a successful BAM, as determined by increase in volume flow of the fistulae.

METHODS

Between 2009 and 2010, data was prospectively collected on patients undergoing BAM of their AVF under ultrasound guidance at our institution. 30 of these patients, consisting of 143 BAMs, were retrospectively analyzed. Data collection included: past medical history, age, number of BAM procedures preformed, volume flow measurement (VFM) in mid-fistulae, size of balloon used, and presence of post procedural wall hematoma. VFM was determined with duplex within one month prior to and subsequent to each BAM performed.

RESULTS

Of the 30 patients, consisting of 143 BAMs, the average age was 69 years old + 15 (range 38-92) with 20 males and 10 females. The most common risk factors were hypertension (n = 27) and diabetes mellitus (n = 16). The average BAM per patient was 4.8 (range 1-7). Of the 143 BAM procedures, 4 were excluded due to absence of preoperative or postoperative duplex. In 139 BAMs, 74 developed a post procedural hematoma as observed on duplex, and 76 showed an increase in VFM. In all BAMs analyzed, there was no correlation observed between the presence of a hematoma and increase in VFM (P = 0.87). Hematomas occurred most frequently during the second BAM procedure, with 24.3% of all hematomas observed. In 139 BAMs, 8 different balloon sizes were used, 3 mm-10 mm, with the 7mm balloon being the most frequently used (n = 34). No significant difference was noted between increase in VFM in 3 mm to 7 mm balloons. A 8 mm balloon was used in 31 BAMs with 22 developing hematomas. Of the 8mm balloon group, a statistical difference was noted between percent increase in VFM with presence of a hematoma and percent increase in VFM without presence of a hematoma (P = 0.027).

CONCLUSIONS

These preliminary data, suggest that a more aggressive approach to BAM, with use of larger balloons to create hematoma formation and minimizing excessive dilatation procedures, may have a significant impact on performing a successful maturation in respects to increase in VFM.

[Hemodialysis fistulas: possibilities of vascular ultrasound]

Vascular ultrasound is an established technique in shunt diagnostics for hemodialysis fistulas that allows non-invasive diagnosis of vascular morphology and hemodynamics. Early detection of shunt stenoses in hemodialysis fistulas or thrombotic occlusions facilitates an interventional decision. High occlusion rates of up to 45% within 1 year in hemodialysis fistulas due to reduced flow volume justify follow up with vascular ultrasound examination. The use of high resolution transducers in vascular ultrasound enables complications, such as stenoses and occlusions to be recognized early therefore allowing preemptive therapy. In the present review the examination technique and strategy, the most important complications and treatment options will be discussed.