Patient-specific hemodynamic feature of central venous disease intervened by stent: A numerical study

Central venous disease (CVD) with stenosis or occlusion is a severe and prevalent complication for chronic hemodialysis (HD) patients, resulting in dialysis access dysfunction. Percutaneous transluminal angioplasty with stent placement (PTS) has become one of the first-line treatments for CVD. In clinical practice, the extra stents would be used if the curative efficacy of a single stent were unsatisfactory. Aiming to evaluate the therapeutic effect of different PTS schemes, computational fluid dynamics (CFD) simulations on four patients were performed to compare the hemodynamic characteristics of real-life HD patients after stent placement. The three-dimensional central vein's models of each patient were built using computational tomography angiography (CTA) images, and idealized models were constructed as contrast. Two inlet velocity modes were imposed to imitate the blood flow rate of healthy and HD patients. The hemodynamic parameters for different patients were investigated, including wall shear stress (WSS), velocity, and helicity. The results showed that the implantation of double stents is able to improve flexibility. When subjected to external force, the double stents have better radial stiffness. This paper evaluated the therapeutic efficacy of stent placement and provided a theoretical basis for CVD intervention in hemodialysis patients.

Covered stents versus balloon angioplasty for failure of arteriovenous access: a systematic review and meta-analysis

INTRODUCTION

Patients with end-stage renal disease may require arteriovenous (AV) access in the form of arteriovenous fistulae (AVFs) or arteriovenous grafts (AVGs) for haemodialysis. AV access dysfunction requires intervention such as plain balloon angioplasty or covered stents to regain patency.

AIM

To systematically review and meta-analyse the patency outcomes of covered stents in failing haemodialysis AV access, compared with balloon angioplasty.

METHODS

The review was first registered on the International Prospective Register of Systematic Reviews (CRD42018069955) before data collection. We searched six electronic databases to identify relevant randomised controlled trials (RCTs) up until August 2020, without language restriction. Two reviewers assessed the suitability and quality of studies for inclusion using the Consolidated Standards of Reporting Trials guidelines. We meta-analysed data using a random-effects model.

RESULTS

We included seven studies including 1147 patients in the systematic review, of which 867 had AVGs and 280 had AVFs. One study was an ongoing RCT. In the meta-analyses, we assessed patients with failing AVGs only. Overall risk of bias was moderate. Covered stents were associated with lower loss of patency versus angioplasty alone at 6, 12 and 24 months (OR 4.48, 95% CI 1.98 to 10.14, p<0.001; OR 4.07, 95% CI 1.74 to 9.54, p=0.001; OR 2.24, 95% CI 1.17 to 4.29, p=0.01, respectively). Covered stents afforded superior access circuit primary patency compared with angioplasty alone at 6 and 12 months (OR 1.91, 95% CI 1.31 to 2.80, p<0.001; OR 1.97, 95% CI 1.14 to 3.41, p=0.02, respectively). This was not significant at 24 months. There was no significant difference in loss of secondary patency between groups at 12 or 24 months (OR 0.74, 95% CI 0.45 to 1.23, p=0.25; OR 0.67, 95% CI 0.29 to 0.154, p=0.34, respectively).

CONCLUSION

Our results support use of covered stents over angioplasty alone, at 6, 12 and 24 months in failing AVGs. Further clinical trials are warranted.

Study protocol of a pilot study on sirolimus-coated balloon angioplasty in salvaging clotted arteriovenous graft

Background

In arteriovenous graft (AVG) for haemodialysis, the primary cause of failure is venous stenosis of the graft-vein junction from neointimal hyperplasia (NIH), resulting in thrombosis. While interventions to salvage clotted AVG are known to have high clinical success rates, long-term patency rates have been suboptimal. Drug-coated balloon (DCB) has been used to treat stenosed arteriovenous access in recent years with encouraging results but data on its effect in clotted AVG is unavailable.

Methods

This is an investigator-initiated, single-center, single-arm prospective pilot study to determine the safety and outcome of the sirolimus-coated balloon (SCB) in the salvage of thrombosed AVG. Twenty patients who undergo successful percutaneous thrombectomy will receive treatment with SCB at the graft vein junction. The patients will be followed-up for 6-months. The primary endpoint is the patency rates at 3-month while the secondary endpoints are the patency rates and the number of interventions needed to maintain patency at 6-month.

Discussion

Unremitting efforts have been made to prolong the patency of AV accesses over the years. DCB angioplasty combines mechanical and biological treatment for vascular stenosis. Sirolimus, being a cystostatic anti-proliferative agent, has been successfully used in coronary artery interventions. As the primary pathology of vascular stenosis in the dialysis circuit is neointimal hyperplasia, the use of sirolimus in balloon angioplasty may be effective. With this prospective study, we evaluate the efficacy and safety of SCB in patients with clotted AVG.

Trial registration

ClinicalTrials.gov Identifier: NCT03666208 on 11 September 2018.

Central venous disease in hemodialysis patients

Central venous disease (CVD) is difficult to treat and often resistant to treatment. In CVD, hemodialysis vascular access should sometimes be abandoned, or in serious cases, the patient's life may be threatened. Therefore, prevention is ideal. However, as the prevalence of chronic kidney disease (CKD) has increased steadily with population aging, CKD patients with a peripherally inserted central catheter (PICC) are encountered frequently. PICCs can cause CVD, and the basilic vein, which is regarded as the important last option for native arteriovenous fistula (AVF) creation in end-stage renal disease (ESRD) patients, is destroyed frequently after its use as the entry site of PICC. The most well-established risk factors for CVD are a history of central venous catheter (CVC) insertion and its duration of use. Therefore, to reduce the incidence of CVD, catheterization in the central vein (CV) should be minimized, along with its duration of use. In this review, we will first explain the basic territories of the CV and introduce its pathophysiology, clinical features, and advanced treatment options. Finally, we will emphasize prevention of CVD.

Treatment of failing arterio-venous dialysis graft by angioplasty, stent, and stent graft: Two-years analysis of patency rates and cost-effectiveness

The objective of this prospective randomized single-center study was to compare primary and secondary patency rates, number of percutaneous transluminal angioplasty (PTA) interventions and cost-effectiveness among PTA, deployment of a stent, or a stent graft in the treatment of failing arteriovenous dialysis grafts (AVG) due to restenosis in the venous anastomosis or the outflow vein. Altogether 60 patients with failing AVG and restenosis in the venous anastomosis or the outflow vein were randomly assigned to either PTA, placement of a stent (E-Luminexx^®) or stent graft (Fluency Plus^®). After the procedure, patients with stent or stent graft received dual antiplatelet therapy for the next three months. Follow-up angiography was scheduled at 3, 6, and 12 months unless requested earlier due to suspected stenosis or malfunction of the access. Subsequently, angiography was performed only if requested by the clinician. During a median follow-up of 22.4 (IQR=5.7) months patients with PTA, stent, or stent graft required 3.1±1.7, 2.5±1.7, or 1.7±2.1 (P=0.031) secondary PTA interventions. The primary patency rates were 0, 18 and 65% at 12 months and 0, 18 and 37% at 24 months in the PTA, stent, and stent graft group respectively (P<0.0001). The cost of the procedures in the first two years was €7,900±€3,300 in the PTA group, €8,500±€4,500 in the stent group, and €7,500±€6,200 in the stent graft group (P=0.45). We conclude that the treatment of failing dialysis vascular access by the deployment of a stent graft significantly improves its primary patency rates and decreases the number of secondary PTA interventions; however, the reduction in costs for maintaining AVG patency is not significant.

Clinical and Economic Benefits of Stent Grafts in Dysfunctional and Thrombosed Hemodialysis Access Graft Circuits in the REVISE Randomized Trial

PURPOSE

To compare reinterventions and associated costs to maintain arteriovenous graft hemodialysis access circuits after rescue with percutaneous transluminal angioplasty (PTA), with or without concurrent Viabahn stent grafts, over 24 months.

MATERIALS AND METHODS

This multicenter (n = 30 sites) study evaluated reintervention number, type, and cost in 269 patients randomized to undergo placement of stent grafts or PTA alone. Outcomes were 24-month average cumulative number of reinterventions, associated costs, and total costs for all patients and in 4 groups based on index treatment and clinical presentation (thrombosed or dysfunctional).

RESULTS

Over 24 months, the patients in the stent graft arm had a 27% significant reduction in the average number of reinterventions within the circuit compared to the PTA arm (3.7 stent graft vs 5.1 PTA; P = .005) and similar total costs ($27,483 vs $28,664; P = .49). In thrombosed grafts, stent grafts significantly reduced the number of reinterventions (3.7 stent graft vs 6.2 PTA; P = .022) and had significantly lower total costs compared to the PTA arm ($30,329 vs $37,206; P = .027). In dysfunctional grafts, no statistical difference was observed in the number of reinterventions or total costs (3.7 stent graft vs 4.4 PTA; P = .12, and $25,421 stent graft and $22,610 PTA; P = .14).

CONCLUSIONS

Over 24 months, the use of stent grafts significantly reduced the number of reinterventions for all patients, driven by patients presenting with thrombosed grafts. Compared to PTA, stent grafts reduced overall treatment costs for patients presenting with thrombosed grafts and had similar costs for stenotic grafts.

Spanish Clinical Guidelines on Vascular Access for Haemodialysis

Vascular access for haemodialysis is key in renal patients both due to its associated morbidity and mortality and due to its impact on quality of life. The process, from the creation and maintenance of vascular access to the treatment of its complications, represents a challenge when it comes to decision-making, due to the complexity of the existing disease and the diversity of the specialities involved. With a view to finding a common approach, the Spanish Multidisciplinary Group on Vascular Access (GEMAV), which includes experts from the five scientific societies involved (nephrology [S.E.N.], vascular surgery [SEACV], vascular and interventional radiology [SERAM-SERVEI], infectious diseases [SEIMC] and nephrology nursing [SEDEN]), along with the methodological support of the Cochrane Center, has updated the Guidelines on Vascular Access for Haemodialysis, published in 2005. These guidelines maintain a similar structure, in that they review the evidence without compromising the educational aspects. However, on one hand, they provide an update to methodology development following the guidelines of the GRADE system in order to translate this systematic review of evidence into recommendations that facilitate decision-making in routine clinical practice, and, on the other hand, the guidelines establish quality indicators which make it possible to monitor the quality of healthcare.

Stent Grafts Provided Superior Primary Patency for Central Venous Stenosis Treatment in Comparison with Angioplasty and Bare Metal Stent: A Retrospective Single Center Study on 70 Hemodialysis Patients

PURPOSE

To compare patency in dialysis patients following different endovascular treatment of symptomatic central venous stenosis.

MATERIALS AND METHODS

A 10-year retrospective evaluation in 70 patients (32 men) dialyzing through vascular access (33, 47%) and tunneled catheters (37, 53%) was made. Three cohorts were compared: angioplasty alone (22), bare metal stent (28), and stent graft (20). Patencies were described with Kaplan-Meier method, and Cox uni- and multivariate models were analyzed to find factors associated.

RESULTS

All patients had a favorable anatomical and clinical outcome. Restenosis occurred in 22 (31%) of 70 patients requiring 41 additional interventions; 34 of 70 patients died (median follow-up 19.4 months). Primary patency at 3, 6, 12, and 24 months was 100%, 100%, 100%, and 84% for stent graft versus 90%, 79%, 58%, and 43% for angioplasty (P = .014) versus 84%, 80%, 75%, and 46% for bare-metal stent (P = .062). The overall comparison was more favorable for stent graft (P = .020) when the sites of lesions were matched. Patencies for angioplasty and bare-metal stents were equivalent (P = .141). A lower risk of restenosis (hazard rate [HR] 0.20, confidence interval [CI] 0.06-0.7) and fewer reinterventions (P < .01) were associated with stent graft, whereas age (HR 1.04, CI 1.001-1.08) and cardiovascular disease (HR 2.26, CI 1.06-4.84) influenced the overall survival. No difference in assisted primary patency was found.

CONCLUSION

Stent graft seems to improve primary patency for central venous stenosis and requires fewer reinterventions in a dialysis population with a high prevalence of long-term catheters.

Endovascular Stent Placement for Hemodialysis Arteriovenous Access Stenosis

This study aims to report the outcomes of nitinol and polytetrafluoroethylene covered stent placement to treat hemodialysis arteriovenous access stenosis at a single center over a five-year period. Clinical and radiological information was reviewed retrospectively. Poststent primary and secondary patency rates were determined using Kaplan-Meier analysis. Ten clinical variables were subjected to multivariate Cox regression analysis to determine predictors of patency after stent placement. During the study period 60 stents were deployed in 45 patients, with a mean follow-up of 24.5 months. The clinical and anatomical success rate was 98.3% (59/60). Poststent primary patency rates at 6, 12, and 24 months were 64%, 46%, and 35%, respectively. Poststent secondary patency rates at 6, 12, and 24 months were 95%, 89%, and 85%, respectively. Stent placement for upper arm lesions and in access less than 12 months of age was associated with reduced primary patency (adjusted hazards ratio [HR] 5.1, p = 0.0084, and HR 3.5, p = 0.0029, resp.). Resistant or recurrent stenosis can be successfully treated by endovascular stent placement with durable long-term patency, although multiple procedures are often required. Stent placement for upper arm lesions and in arteriovenous access less than 12 months of age was associated with increased risk of patency loss.

The Role of Endovascular Stents in Dialysis Access Maintenance

Vascular stenosis is most often the culprit behind hemodialysis vascular access dysfunction, and although percutaneous transluminal angioplasty remains the gold standard treatment for vascular stenosis, over the past decade the use of stents as a treatment option has been on the rise. Aside from the 2 Food and Drug Administration-approved stent grafts for the treatment of venous graft anastomosis stenosis, use of all other stents in vascular access dysfunction is off-label. Kidney Disease Outcomes Quality Initiative recommends limiting stent use to specific conditions, such as elastic lesions and recurrent stenosis; otherwise, additional adapted indications are in procedure-related complications, such as grade 2 and 3 hematomas. Published reports have shown the potential use of stents in a variety of conditions leading to vascular access dysfunction, such as venous graft anastomosis stenosis, cephalic arch stenosis, central venous stenosis, dialysis access aneurysmal elimination, cardiac implantable electronic device-induced stenosis, and thrombosed arteriovenous grafts. Although further research is needed for many of these conditions, evidence for recommendations has been clear in some; for instance, we know now that stents should be avoided along cannulation sites and should not be used in eliminating dialysis access aneurysms. In this review article, we evaluate the available evidence for the use of stents in each of the aforementioned conditions leading to hemodialysis vascular access dysfunctions.

Partial Aneurysmectomy of Venous Aneurysms in Arteriovenous Dialysis Fistulas

Upper extremity native arteriovenous fistulas (AVFs) continue to be the standard of care for hemodialysis patient’s access. Although autogenous fistulas are superior to catheters and synthetic grafts, they are not without their own complications. One complication is venous aneurysms that can lead to skin erosion, bleeding, and site loss. Although traditionally repaired with ligation, interposition grafts, or stent placement, in this article, we discuss our experience with aneurysmorrhaphy utilizing a thoracoabdominal (TA) stapler. Thirteen aneurysms were treated with the TA stapler at a single, nonuniversity hospital for all patients from 2012 to 2014. The average aneurysm diameter was 3.6 cm, and the average fistula age was 57.9 months. There were no bleeding complications or recurrences. The primary patency was 80% at 6 months, with a primary assisted patency of 90% during the same time frame. Aneurysmorrhaphy with the TA stapler appears to be a safe and viable option for the treatment of venous aneurysms associated with AVFs.

Dual stent migration to the heart and pulmonary artery

The practice of intravascular stenting largely grew out of the concept of stenting the coronaries in acute myocardial infarction. According to the recent United States Renal Data System data registry, there has been a significant increase in endovascular intervention (1.8-fold increase-from 52,380 to 98,148) with a 2.2-fold increase in stent deployment in hemodialysis access (3792-8514). With the increasing use of endovascular stents in the management of dialysis access stenosis, the incidence of stent-related complications has increased significantly. Stent-related complications include stent restenosis, thrombosis (narrowing of the vessel lumen and being a nidus for thombus formation), stent shortening, stent fracture, stent infection, and stent migration. Physiologic variation in the diameter of veins due to respiration, which along with the geometry of the stent, can lead to a shortening lengthening of the stent-resulting in poor wall contact or high-speed impact of shock; in the case of trauma, mechanical bucking can result in tortuous blood vessels thereby resulting in stent migration (however proving this association was not the aim of this article). We report a case of a 44-year-old female with end-stage renal disease on hemodialysis, with stent placement to treat a compromised arteriovenous graft. There have been many cases of stent migration in the past; however, this is the first case of dual stent migration to the heart and pulmonary artery from an unusual (lower extremity) arteriovenous graft location.

A Patient with Recurrent Arteriovenous Graft Thrombosis

Arteriovenous grafts (AVGs) are prone to frequent thrombosis that is superimposed on underlying hemodynamically significant stenosis, most commonly at the graft-vein anastomosis. There has been great interest in detecting AVG stenosis in a timely fashion and performing preemptive angioplasty, in the belief that this will prevent AVG thrombosis. Three surveillance methods (static dialysis venous pressure, flow monitoring, and duplex ultrasound) can detect AVG stenosis. Whereas observational studies have reported that surveillance with preemptive angioplasty substantially reduces AVG thrombosis, randomized clinical trials have failed to confirm such a benefit. There is a high frequency of early AVG restenosis after angioplasty caused by aggressive neointimal hyperplasia resulting from vascular injury. Stent grafts prevent AVG restenosis better than balloon angioplasty, but they do not prevent AVG thrombosis. Several pharmacologic interventions to prevent AVG failure have been evaluated in randomized clinical trials. Anticoagulation or aspirin plus clopidogrel do not prevent AVG thrombosis, but increase hemorrhagic events. Treatment of hyperhomocysteinemia does not prevent AVG thrombosis. Dipyridamole plus aspirin modestly decreases AVG stenosis or thrombosis. Fish oil substantially decreases the frequency of AVG stenosis and thrombosis. In patients who have exhausted all options for vascular access in the upper extremities, thigh AVGs are a superior option to tunneled internal jugular vein central vein catheters (CVCs). An immediate-use AVG is a reasonable option in patients with recurrent CVC dysfunction or infection. Tunneled femoral CVCs have much worse survival than internal jugular CVCs.

Arteriovenous graft for hemodialysis, graft venous anastomosis closure - current state of knowledge. Minireview

Backround. The use of artificial vascular grafts (arteriovenous graft, AVG) is indicated in patients in hemodialysis programs if the subcutaneous venous bed is exhausted or unsuitable for arteriovenous fistula (AVF) creation. The native fistula should be the hemodialysis access of first choice: AVF has better results in terms of function and potential complications. However, the use of AVG is necessary in some patients. In these patients, extensive clinical examination, color duplex sonography and angiography should be performed prior to indication. The technique of graft implantation requires respect for geometric relations for the graft anastomoses to minimize the formation of intimal hyperplasia mainly on the venous anastomosis. The main complications of AVG are stenosis on the venous anastomosis (VAG), causing closure of graft and graft infection. The cumulative function of AVG is 59-90% in the first year and 50-82% in the second year. Arteriovenous graft stenosis leading to thrombosis is a major cause of complications in patients undergoing hemodialysis. The purpose of this review is to summarise current knowledge of the diagnostics and treatment of graft thrombosis and discuss the issue in combination with relevant publications via Pubmed database.

CONCLUSION

The most frequent cause of failure of AVG for hemodialysis is stenosis and closure by VAG. AVG closure can be addressed surgically, endovascularly (amenable to thrombectomy by radiological or surgical means) and by hybrid performance.

Predictors of patency after balloon angioplasty in hemodialysis fistulas: a systematic review

Percutaneous transluminal angioplasty (PTA) is an established treatment for dysfunctional hemodialysis fistulas. This article systematically reviews evidence for predictors of patency after PTA. Outcomes assessed were primary, assisted primary, and secondary patency after intervention, and findings were summarized descriptively. This review included 11 nonrandomized observational studies of 965 fistulas in 939 patients. Follow-up ranged from 0 days to 10 years. Study quality was overall suboptimal. Newer fistulas and longer lesion length may be associated with primary patency loss after PTA. Further studies are needed to confirm these findings, to identify potentially modifiable factors, and to guide the testing of new endovascular devices.

Stent salvage of arteriovenous fistulas and grafts

OBJECTIVES

This study analyzes our experience using stents to salvage dysfunctional hemodialysis access sites at a single institution.

METHODS

We examined the outcomes of 42 consecutive patients who had covered (36 patients) or bare-metal (9 patients) stent intervention for hemodialysis access salvage.

RESULTS

Of our 42 male patients, 11 had stent salvage of an arteriovenous fistula, which yielded postintervention primary and secondary 6-month patencies of 27% and 55%, respectively. For 31 patients with arteriovenous grafts, the postintervention primary and secondary 6-month patencies were 26% and 29%, respectively. Patency rates were superior for stents placed in patent access sites, in fistulas compared to grafts, and when stents were placed in forearm sites although only the latter achieved statistical significance.

CONCLUSIONS

Stents can extend patency for the thrombosed or failing arteriovenous access, but results are poor once thrombosis has occurred. Stent placement appears to be more effective in fistulas compared to grafts.

Central venous disease in hemodialysis patients: an update

Central venous occlusive disease (CVD) is a common concern among the hemodialysis patient population, with the potential to cause significant morbidity. Endovascular management of CVD, comprising percutaneous balloon angioplasty and bare-metal stenting, has been established as a safe alternative to open surgical treatment. However, these available treatments have poor long-term patency, requiring close surveillance and multiple repeat interventions. Recently, covered stents have been proposed and their efficacy assessed for the treatment of recalcitrant central venous stenosis and obstruction. Moreover, newly proposed algorithms for the surgical management of CVD warrant consideration. Here, we seek to provide an updated review of the current literature on the various treatment modalities for CVD.

From basic biology to randomized clinical trial: the Beta Radiation for Arteriovenous Graft Outflow Stenosis (BRAVO II)

The BRAVO-II study was a randomized controlled study of endovascular radiation therapy as compared to sham radiation therapy, following angioplasty of a thrombosed PRFE graft. The results did not show a benefit of endovascular radiation therapy, albeit in the context of an early termination of the study at less than 50% enrollment due to business reasons. Emphasis is laid on the fact that there may still be a role for radiation therapy in specific clinical settings associated with dialysis vascular access dysfunction.

Biological grafts for hemodialysis access: historical lessons, state-of-the-art and future directions

The vast majority of arteriovenous grafts (AVG) have been constructed using expanded polytetrafluoroethylene (ePTFE). While ePTFE grafts have the advantage of being relatively inexpensive and easy to manufacture, distribute, ship, and store, their primary patency rates are disappointing when compared with the native AVF. Though use of arteriovenous fistulas (AVF) in the United States has increased substantially, approximately 25% of hemodialysis patients continue to use AVG as their vascular access. We present here a comprehensive review of biological grafts and their use in hemodialysis vascular access. In this review, we discuss the use of synthetics and then explore the evolution of biological grafts over the past 20 years, their clinical impact, and future challenges in widespread clinical use in hemodialysis patients. Provided are in depth descriptions of currently used nonbiological arteriovenous grafts and the recent approaches in increasing the patency of synthetic grafts. Recent technological advances using tissue-engineered AVGs have shown promise for patients receiving hemodialysis and their potential to provide an attractive, viable option for vascular access have been discussed.

Endovascular stent migration to the right ventricle causing myocardial injury

Central stenosis of the subclavian and internal jugular veins is common in end stage renal disease. Treatment of these stenoses is difficult as these veins respond poorly to angioplasty alone and often require metallic stents to ensure patency. These stents are not without complications. Reports of stent fracture, thrombosis and vessel rupture abound in the literature. Stent migration can occur when used in large central veins leading to severe consequences such as pulmonary infarction, tricuspid regurgitation and right sided heart failure. In this report, we report a case of a subclavian vein stent which migrated into the right heart and caused subendocardial injury. As the use of vascular stents is becoming a common treatment option for central venous stenosis, the occurrences of serious complications associated with the stents are likely to rise.

Role of stent grafts for the treatment of failing hemodialysis accesses

Covered stents or stent grafts are exciting new products with multiple applications for patients with vascular disease, including hemodialysis access-related complications. Although most of the current uses of stent grafts in these settings are "off-label" (ie, not approved by the US Food and Drug Administration) several studies are currently underway to provide the necessary data to support their application. It is clear that stent grafts provide a rapid, effective means for endovascular repair of ruptured access vessels. The commercially available devices and their current applications for treating access-related complications, including aneurysms/pseudoaneurysms, venous outflow stenoses, cephalic arch lesions, ruptures, and diffuse access stenoses, will be reviewed in this article. Available data are reported along with our current clinical practice and algorithms.

Vascular access surveillance: an ongoing controversy

Hemodialysis vascular access surveillance continues to be widely recommended despite ongoing controversy as to its benefit in prolonging access patency compared with clinical monitoring alone. The most common screening tests are access blood flow and dialysis venous pressure measurements. When surveillance test results cross a predetermined threshold, accesses are referred for intervention with correction of stenosis to reduce future thrombosis and prolong access survival. Current surveillance strategies have four components: (1) underlying condition; (2) screening test; (3) intervention; and (4) outcomes. However, limitations exist within each component that may prevent achieving the desired outcomes. This review discusses these limitations and their consequences. To date, randomized controlled trials have not consistently shown that surveillance improves outcomes in grafts, and there is limited evidence that surveillance reduces thrombosis without prolonging the life of native fistulae. In conclusion, current evidence does not support the concept that all accesses should undergo routine surveillance with intervention.

Vascular Access Flow Reduction for Arteriovenous Fistula Salvage in Symptomatic Patients with Central Venous Occlusion

Purpose

Vascular access patients with central vein (CV) stenosis or occlusion may have significant symptoms. Treatment is generally by balloon angioplasty, with or without stenting. However, CV lesions may not be correctable and when treated, tend to recur. Surgical bypass of CV obstruction is a major procedure and ligation of the access may leave the patient dependent on catheter dialysis. We review a precision inflow banding procedure to limit vascular access flow and pressure for symptomatic patients with CV obstruction while preserving access functionality.

Materials and Methods

All individuals with symptomatic CV occlusive disease who underwent an autogenous vascular access inflow restriction procedure by the two senior authors were identified. All had failed attempts to correct CV lesions by angioplasty and stent placement. A precision banding procedure was used for access inflow reduction with the addition of real-time intravascular flow monitoring.

Results

Twenty-two patients were identified. Ages were 22–72 years (mean=43 years). Nine patients (40.9%) were women, and 8 (36.4%) obese. Mean access flow was 1640 mL/minute before banding decreased to 820 mL/minute after banding (P<.01). All patients had access salvage. Swelling resolved promptly in 20 patients and was markedly improved in two individuals. Three patients underwent aneurysm repair with simultaneous inflow banding and decreased intra-access pressure after flow restriction. Two fistulas failed at eight and 13 months. Mean follow-up was 8 months.

Conclusions

The symptoms of hemodialysis vascular access patients associated with non-correctable central venous lesions resolved successfully and their access was maintained using a precision inflow banding procedure.