Ultrasound-guided nitinol stent implantation to treat early restenosis of arteriovenous fistula: A 69-case study with 1-year outcome

BACKGROUND

To investigate the feasibility, methods and effects of interventional ultrasound in nitinol stent implantation to treat early restenosis after percutaneous transluminal angioplasty (PTA) in autogenous arteriovenous fistula (AVF).

METHODS

From April 2018 to December 2021, 69 patients with early restenosis of AVF received ultrasound-guided nitinol stent implantation (UNSI) and were followed-up. Imaging features of the stent and procedure by ultrasound were observed. The technical success rate, clinical success rate and incidence of complications were recorded and counted. Target lesion primary patency (TLPP), access circuit primary patency (ACPP) and access circuit secondary patency (ACSP) were estimated.

RESULTS

Ultrasonography can show the structure of the stent and guide the stenting process clearly. Both the technical and clinical success rates were 100%. Thirty-one patients had in-stent restenosis (ISR), which was treated by plain balloon (PB) PTA or drug coated balloon (DCB) PTA. The TLPP at 3, 6, 12 and 24 months were 100.0%, 94.2%, 63.4% and 39.6%, respectively. The ACPP at 3, 6, 12 and 24 months were 98.6%, 91.6%, 60.2% and 35.2%, respectively. The ACSP at 3, 6, 12 and 24 months were 98.6%, 98.6%, 95.6% and 93.8%, respectively. The TLPP of ISR after DCB PTA at 3, 6 and 12 months were 100.0%, 100.0% and 93.6%, respectively.

CONCLUSIONS

This pilot study indicates ultrasonography can accurately guide nitinol stent implantation in AVF and this technique is a feasible and minimally invasive treatment for early restenosis after PTA with good short- and medium-term patency. DCB PTA may be used to deal with the ISR and is a way to prolong the patency of nitinol stent.

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.

Arteriovenous fistulas for hemodialysis: Brief review and current problems

The number of people worldwide living with end-stage renal disease is increasing. Arteriovenous fistulas are the preferred method of vascular access in patients who will require hemodialysis. As the number of patients with arteriovenous fistulas grows, the role of physicians who intervene who maintain and salvage these fistulas will grow in importance. This review aims to familiarize practitioners with the rationale for arteriovenous fistula creation, the detection of fistula dysfunction, and the state of the art on fistula maintenance and preservation. Current controversies are briefly reviewed.

Feasibility of routine ultrasound-guided percutaneous transluminal angioplasty in the treatment of native arteriovenous fistula dysfunction

BACKGROUND

Stenosis is the main cause of arteriovenous fistula failure and is due to neointimal hyperplasia. Percutaneous transluminal angioplasty is the gold standard for patients with vascular access stenosis. The aim of the study was to evaluate the efficacy and safety of ultrasound-guided percutaneous transluminal angioplasty in the treatment of native arteriovenous fistula venous stenosis.

METHODS

The need for intervention was determined by physical examination and duplex ultrasound in 162 patients. All patients with failing or not maturing arteriovenous fistula were treated in the outpatient setting under ultrasound guidance. Procedural success was assessed with repeated post-procedural ultrasound examinations. All procedures were performed under local anesthesia by a single nephrologist and were performed in a single vascular laboratory, while follow-up ultrasound was performed in the dialysis unit of destination.

RESULTS

Early technical success was obtained in 95.6% of cases (154 of 162). Complications occurred in 22 patients (13.5%) with no major complication requiring surgical or fluoroscopic endovascular intervention. Primary patency at 6 and 12 months was 84% and 69.8%, respectively. Risk factors for arteriovenous fistula failure/secondary percutaneous transluminal angioplasty were vascular access low blood flow rate and vintage, as well as the need for thrombolysis during the first percutaneous transluminal angioplasty.

CONCLUSION

Ultrasound-guided percutaneous transluminal angioplasty is a valuable tool to treat vascular access stenosis.

Pull-through technique combined with percutaneous angioplasty for treating high-grade arteriovenous fistula stenosis

PURPOSE

The aim of this study was to investigate the effectiveness of a new pull-through technique through a brachial artery approach combined with angioplasty for the treatment of arteriovenous fistula.

METHODS

In this retrospective study, a total of 56 arteriovenous fistula patients with high-grade stenosis induced by arteriovenous fistula, which was divided into pull-through technique through a brachial artery approach (pull-through group, n = 28) and solely through a venous approach (control group, n = 28), were analyzed. Both groups underwent percutaneous transluminal angioplasty treatments simultaneously.

RESULTS

The success rate of the pull-through group (89.3%, 25 out of 28) was similar to that of the control group (75.0%, 21 out of 28, p = 0.296). Fistula restenosis occurred with time in both groups but no significant differences in the post-operative fistula patency were found between the pull-through and control groups in follow-ups at 3, 6, and 12 months (71.4% vs 67.9%, 57.1% vs 60.7%, and 20.0% vs 30.0%, respectively, p > 0.05). No significant difference in the post-operative patency rate in patients with diabetes, hypertension, or coronary disease was found between the pull-through and control groups in the follow-ups at 3 and 12 months, respectively. The pull-through group had significantly shorter operation times compared with the control group (45 ± 9 min vs 65 ± 15 min, p < 0.001). No surgical complications were reported in the pull-through group in contrast to three cases (11%, 3 out of 28) with puncture hematoma and acute occlusion in the control group.

CONCLUSION

The pull-through technique combined with percutaneous transluminal angioplasty is an effective, safe and lasting option to treat high-grade arteriovenous fistula stenosis in the upper limb.

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 Pharmacomechanical Thrombolysis and Angioplasty for Treatment of Acute Thrombotic Prosthetic Arteriovenous Access: 5-Year Experience with 154 Procedures in a Single Center

Pharmacomechanical thrombolysis (PMT) and percutaneous transluminal angioplasty (PTA) for the treatment of acute thrombotic prosthetic arteriovenous access (PAVA) are conventionally guided by radiography, which may cause radiation injury and requires the use of radiographic contrast media. The aim of the present study was to summarize our experience with ultrasound-guided PMT and PTA as an alternative to radiographic guidance. Between December 2012 and October 2016, 114 patients with acute thrombosis of PAVA were treated urgently with ultrasound-guided PMT and PTA to restore blood flow. The patients were followed up every 3 mo postoperatively. The 114 included patients underwent 154 episodes of ultrasound-guided PMT and PTA and were followed up for a mean of 20.7 ± 9.1 mo. The technical success rate was 91.6%, and the clinical success rate was 97.4%. Post-intervention-assisted primary patency rates at 3, 6, 12 and 24 mo were 90.8%, 78.8%, 66.3% and 50.9%, respectively. Post-intervention secondary patency rates at 3, 6, 12 and 24 months were 96.3%, 94.5%, 90.6% and 85.4%, respectively. PMT and PTA for the treatment of PAVA were performed successfully under the guidance of ultrasound with a success rate similar to that under radiographic guidance, thus avoiding radiation injury and contrast medium use, although close surveillance and timely intervention are imperative to ensure long-term patency.

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.

Translesional pressure ratio predicts technical outcome and patency in angioplasty on outflow stenosis of hemodialysis graft

PURPOSE

Translesional pressure ratio (TLPR) indicating fractional flow reserve has been applied to physiological assessment of moderate coronary stenosis. The role of TLPR in hemodialysis (HD) patients with arteriovenous graft (AVG) outflow stenosis undergoing percutaneous transluminal angioplasty (PTA) is unclear. The purpose of the study was to assess the validation of TLPR in such patients undergoing PTA.

METHODS

Patients with pure AVG outflow stenosis confirmed by angiography were prospectively enrolled. A TLPR defined as a ratio of the mean pressure downstream to the lesion(s) to the vein-sided intragraft pressure was measured using a catheter pullback method. Relationship among TLPR, angiographic result and clinical outcome within 6 months was detected.

RESULTS

Of 65 PTAs, the post-PTA TLPR significantly increased (from 0.28±0.10 to 0.50±0.11; p<0.0001). A significantly greater pre-PTA TLPR was observed in the simple lesions at baseline compared with the complex lesions (0.32±0.09 vs. 0.20±0.06; p<0.0001). Post-PTA TLPR ≥0.5 was powerfully related to angiographic success (p<0.0001). The group with angiographic success plus post-PTA TLPR ≥0.5 had a longer PTA-free patency (208.7±188.7 vs. 109.8±67.7 days; p=0.013) compared with that with angiographic nonsuccess plus post-PTA TLPR <0.5.

CONCLUSIONS

Our data show that TLPR correlates well with lesion properties and angiographic results, and helps predict following unassisted patency. The study suggests TLPR as a hemodynamic indicator during PTA.

Maintaining vascular access: the management of hemodialysis arteriovenous grafts

For the nephrologist and surgeon, maintaining vascular access is a significant challenge in hemodialysis (HD), because the portal is vulnerable to infection, stenosis, and thrombus. Vascular access options for HD include the placement of arteriovenous (AV) fistulas, AV grafts, and double-lumen, cuffed central vein catheters. Catheter use is generally associated with higher rates of infection and could compromise the adequacy of HD. Primary AV fistulas, which are generally recommended and provide excellent HD access, are not always the ideal choice for certain patients, such as the elderly or patients with diabetes mellitus. AV grafts allow for a large surface area available for cannulation, and thrombosed grafts have longer patency rates after revision than do revised fistulas. Although both AV fistulas and AV grafts are vulnerable to thrombosis and/or stenosis, surveillance and techniques such as Doppler ultrasound and intravascular ultrasound can minimize such complications. In addition, pharmacotherapeutic options are being studied to determine whether these complications can be prevented. Studies using a variety of pharmacologic agents have been conducted to determine whether stenosis and graft thrombosis can be prevented and have produced varying results. The use of warfarin can result in significant bleeding, but agents such as fish oil and angiotensin-converting enzyme inhibitors have shown some effect in increasing the patency in AV grafts and fistulas. Additional randomized trials with at least 1 or 2 yrs of follow-up are necessary to assess the long-term use of these pharmacotherapies.