Use of Wallstents for hemodialysis access-related venous stenoses and occlusions untreatable with balloon angioplasty

Outcomes of stent grafts for treatment of central venous disease in hemodialysis patients

BACKGROUND

To evaluate the effectiveness of stent graft (SG) for the treatment of central venous disease (CVD) in hemodialysis patients.

METHODS

Between January 2014 and April 2022, 122 patients on hemodialysis with symptomatic CVD were treated with percutaneous transluminal angioplasty (PTA) and bare-metal stent (BMS) or SG placement. The mean follow-up was 14.5 months (IQR: 8.0, 24.2). Patency rates of the target sites were calculated using Kaplan-Meier and log-rank studies. Multivariate Cox proportional hazard models were used to evaluate the association between various characteristics and target site primary patency.

RESULTS

Technical success rate was 100%. At 3, 6, 12, and 24 months, the target sites primary patency rates were 86.4%, 74.2%, 45.1%, and 30.4% for PTA; 94.7%, 78.6%, 60.8%, and 45.6% for BMS; and 94.0%, 92.0%, 82.4%, and 66.8% for SG, respectively, and the assisted primary patency rates were 86.5%, 80.4%, 63.8%, and 46.0% for PTA; 94.7%, 89.5%, 77.5%, and 71.1% for BMS; 100%, 100%, 97.8%, and 83.4% for SG, respectively. The Kaplan-Meier analysis indicated that SGs achieved better primary and assisted primary patency than PTA or BMS (p<0.05). SG use and concomitant stenosis were the independent predictors of target site primary patency dysfunction in the multivariate analysis.

CONCLUSIONS

This study confirmed the better long-term patency of SG in comparison with PTA and BMS for the treatment of CVD in hemodialysis patients.

A systematic review of right atrial bypass grafting in the management of central venous occlusive disease in patients undergoing hemodialysis

INTRODUCTION

Central venous occlusive disease (CVOD) is a complication that can occur in patients with end-stage renal disease who are receiving hemodialysis. When CVOD develops, patients often require multiple re-interventions to maintain their dialysis access. CVOD can be treated by various strategies such as balloon angioplasty, stenting, lower limb or extra-anatomical grafts, hybrid grafts or surgical bypasses such as right atrial (RA). In this systematic review, we aim to evaluate the indications, technical aspects, and outcomes after RA bypass grafting for the treatment of CVOD in hemodialysis patients.

METHODS

A systematic and comprehensive literature search was conducted using various electronic databases. We included articles that reported described and reported outcomes of RA bypass grafting for the treatment of CVOD in hemodialysis patients. A narrative review of the indications and technical aspects of RA bypass grafting was performed. We also pooled and reported the primary patency, secondary patency, postoperative complications, and 30-day mortality of RA bypass grafting.

RESULTS

A total of 21 studies with 55 patients who underwent RA bypass grafting were included in our systematic review. Follow-up period ranged from 0.5 to 84 months. The mean pooled primary patency and secondary patency of RA bypass grafting were 8.1 ± 4.9 and 21.7 ± 20.1 months, respectively. The incidence of early postoperative complications such as surgical site infection, bleeding, and access thrombosis was 0%, 4%, and 4%, respectively. The overall 30-day mortality was 4%.

CONCLUSIONS

This systematic review summarizes the patient characteristics, technical features and outcomes of RA bypass grafting in the treatment of hemodialysis-related CVOD. RA bypass grafting may be a viable last-resort option when less invasive or conventional treatment options have been exhausted.

Central vein stenosis in hemodialysis vascular access: clinical manifestations and contemporary management strategies

Central venous stenosis is a significant and frequently encountered problem in managing hemodialysis (HD) patients. Venous hypertension, often accompanied by severe symptoms, undermines the integrity of the hemodialysis access circuit. In central venous stenosis, dialysis through an arteriovenous fistula is usually inefficient, with high recirculation rates and prolonged bleeding after dialysis. Central vein stenosis is a known complication of indwelling intravascular and cardiac devices, such as peripherally inserted central catheters, long-term cuffed hemodialysis catheters, and pacemaker wires. Hence, preventing this challenging condition requires minimization of central venous catheter use. Endovascular interventions are the primary approach for treating central vein stenosis. Percutaneous angioplasty and stent placement may reestablish vascular function in cases of elastic and recurrent lesions. Currently, there is no consensus on the optimal treatment, as existing management approaches have a wide range of patency rates.

Clinical outcomes of endovascular therapy with vascular stents for central venous obstruction in hemodialysis patients

BACKGROUND

Symptomatic central venous obstruction (CVO) is sometimes observed in patients undergoing hemodialysis. Angioplasty is generally performed for salvage purposes, and stent implantation is performed as a last resort to prevent permanent venous occlusion. However, published reports about the clinical outcomes of stenting for CVO have been limited by the small number of included patients and the relatively old generation of analyzed stents. This study aimed to clarify the safety and efficacy of endovascular therapy (EVT) using stents for symptomatic CVO in contemporary practice.

METHODS

This retrospective review was performed between May 2012 and August 2021. We retrospectively analyzed consecutive 31 lesions (31 patients, 64 ± 10.7 years old) treated with a vascular stent for elastic recoil after balloon angioplasty or recurrent stenosis <3 months after angioplasty. The primary outcome was primary patency, defined as freedom from target lesion revascularization. The secondary outcome was assisted primary patency, defined as freedom from permanent occlusion of the target stents.

RESULTS

In all cases, stents were successfully deployed on the target lesions. No EVT-related complications were observed. Self-expandable and balloon-expandable stents were used in 26 and 5 lesions, respectively. The median follow-up period was 18 months (interquartile range, 7-40). Kaplan-Meier analysis revealed that the primary patency rates were 66.1 % at 6 months, 61.7 % at 12 months, and 38.4 % at 24 months after EVT. The assisted primary patency rate was 70.3 % 24 months after EVT. In the multivariate analysis, younger age was the only independent predictor of target lesion revascularization (hazard ratio: 0.92, 95 % CI: 0.85-0.99, p = 0.04).

CONCLUSIONS

Stent implantation for CVO that is resistant to standard angioplasty seems safe and effective.

Venous stent versus conventional stent for the treatment of central vein obstruction in hemodialysis patients: a retrospective study

BACKGROUND

Endovascular treatment is a first-line treatment for upper thoracic central vein obstruction (CVO). Few studies using bare venous stents (BVS) in CVO have been conducted.

PURPOSE

To evaluate the treatment performance of upper thoracic central vein stenosis between BVS and conventional bare stent (CBS) in hemodialysis patients.

METHODS

Hemodialysis patients with upper thoracic central vein obstruction who underwent endovascular treatment at the interventional unit of our institution from 1 January 2008 to 31 December 2018 were enrolled in the present study. CBS was used to treat central vein obstruction in 43 patients and BVS in 34 patients. We compared the primary patency rates and complications between the two stent types. P values < 0.05 were considered statistically significant.

RESULTS

The patient demographic data between the CBS and BVS groups were similar. The characteristics of the lesions, procedures, and complications were not significantly different between the two groups (P > 0.05). There were no statistically significant differences of primary patency rates at three and six months between the BVS and CBS groups (94.1% vs. 86.0% and 73.5% vs. 58.1%, respectively; P > 0.05). The primary patency rate at 12 months in the BVS group was significantly higher than that in the CBS group (61.8% vs. 32.6%; P = 0.008).

CONCLUSION

Endovascular treatment of central vein obstruction with BVS provided a higher primary patency rate at 12 months than CBS.

Tratamento endovascular de doença oclusiva venosa central com fístula arteriovenosa funcionante

Resumo Contexto A maior sobrevida dos doentes dialíticos somada à incapacidade de obtenção de órgãos suficientes para atender a demanda, bem como à dificuldade de acesso aos serviços de saúde, levou ao aumento da fila para transplante e ao prolongamento do tempo de utilização do acesso venoso central para hemodiálise. A etiologia mais comum de estenose de veia central é o acesso venoso central prolongado, pelas lesões intimais decorrentes da presença do cateter. Objetivos Avaliar resultados de angioplastia para tratamento de doença oclusiva venosa central com fístula arteriovenosa periférica funcionante. Métodos Estudo tipo coorte retrospectivo com revisão de prontuários de 47 doentes com lesões estenóticas ou oclusivas. A avaliação dos doentes foi realizada em 30 dias, 6 meses e 1 ano após a recanalização ou correção da estenose com ATP ou ATP/aplicação de stent. Resultados Lesões estenóticas foram encontradas em 25 doentes (53%), e oclusões, em 22 (47%) doentes. A angioplastia percutânea transluminal (ATP) com stent foi utilizada em 64% dos doentes, e angioplastia isolada com balão, em 36% deles. A análise de resultados clínicos mostrou elevada taxa de melhora clínica precoce (30 dias) em 82% dos doentes (intervalo de confiança [IC] 71-93%). Após 1 ano de seguimento, a taxa de perviedade primária foi de 57%, e a taxa de perviedade primária assistida foi de 72% (IC 57-84%). Conclusão O tratamento endovascular das estenoses ou oclusões de veia central sugere melhora clínica dos sintomas e taxas adequadas de perviedade no período de 1 ano, apesar da limitação no tamanho amostral.

Radiological Central Vein Treatment in Vascular Access

In the last decades, the percutaneous interventional approach for the treatment of central venous obstructions (CVO) has become increasingly popular as the treatment of first choice because of its minimal invasiveness and reported success rates. CVOs are caused by a diverse spectrum of diseases which can be broadly categorized into two principal eliciting genera, either benign or malignant obstructions. The large group of benign venous obstructions includes the increasing number of end-stage renal disease patients with vascular access related complications. Due to the invasiveness and complexity of thoracic surgery for benign CVOs, the less invasive percutaneous interventional therapy can generally be considered the preferred treatment option. Initially, the radiological intervention consisted of balloon angioplasty alone, subsequently additional stent placement was applied. This was advocated as either primary placement or secondary in cases of elastic recoil or residual stenosis after percutaneous transluminal angioplasty (PTA). The efficacy of angioplasty of CVO in patients with vascular accesses, either with or without stenting, has been addressed by various studies. Overall, reports indicate an initial technical and clinical success rate above 95% and satisfactory patency rates. However, systematic follow-up and frequent re-interventions are necessary to maintain vascular patency to achieve long-term success.

Stent Graft versus Balloon Angioplasty for Failing Dialysis Access Grafts: A Long-Awaited Advance in the Treatment of Permanent Hemodialysis Access

Arteriovenous grafts (AVGs) for hemodialysis have a high failure rate, often due to the development of stenosis at the graft-to-vein anastomosis. Angioplasty (PTA) has been used for over two decades to treat AVG stenosis, with good technical success but limited AVG patency. Results of a prospective multi-center randomized trial, comparing stent graft to PTA in AVGs, has demonstrated superior access circuit patency for the stent graft group. Recent publication of this clinical study brings us into an exciting new era of dialysis access management using covered stents to improve durability of catheter-based therapy.

Percutaneous intervention for symptomatic central vein stenosis in patients with upper limb arteriovenous dialysis access

Central venous stenosis is an important hindrance to long-term maintenance of arteriovenous access in the upper extremities in dialysis patients.

Aim

The present study was done to determine feasibility and clinical success of endovascular approach for the treatment of symptomatic central venous stenosis associated with significant ipsilateral limb edema in dialysis patients with vascular access in the upper limb.

Methods

A database of hemodialysis patients who underwent endovascular treatment for central venous stenosis from January 2014 to January 2017 at our institute was retrospectively reviewed. Follow-up was variable.

Results

The study included ten patients (6 men and 4 women) with a mean age of 45.2 years, who underwent thirteen interventions during a period of 3 years. The technical success rate for endovascular treatment was 100%. One patient underwent primary PTA (percutaneous transluminal angioplasty). Seven patients underwent primary PTA and stenting. Three patients underwent secondary PTA. One among these patients underwent secondary PTA twice along with fistuloplasty. One patient underwent secondary PTA with stenting. No immediate complications were encountered during the procedure. Our study shows a primary patency rate of 67% and 33% at 6 months and 12 months for PTA with stenting. Our study also shows secondary or assisted primary patency of 75% at 6 months of follow-up.

Conclusions

Endovascular therapy (PTA) with or without stenting for central venous stenosis is safe, with low rates of technical failure. Multiple additional interventions are the rule and long-term patency rate is not very good.

Venous Stent Migration into Right Ventricle

Venous stents (VS) are used to treat central and peripheral stenoses. Stent embolization into a cardiac chamber is a rare, yet serious complication. We present a case of a 61-year-old man with a recently stented arteriovenous graft venous stenosis who developed VS migration into the right ventricle, associated with S. aureus bacteremia.

Paclitaxel-Coated Balloons for the Treatment of Symptomatic Central Venous Stenosis in Dialysis Access: Results from a Randomized Controlled Trial

PURPOSE

To compare the clinically-assessed intervention-free period (IFP) of paclitaxel-coated balloon (PCB) vs conventional balloon angioplasty (CBA) for the treatment of symptomatic central venous stenosis (CVS) in dialysis access.

MATERIALS AND METHODS

Within 20 months, 40 dialysis patients (19/40 arteriovenous fistulae [AVFs] and 21/40 arteriovenous grafts [AVGs]) were randomized to undergo angioplasty either with a PCB (PCB group, n = 20; 14/20 male; age: 56.7) or CBA (CBA group, n = 20; 15/20 male; age: 57). There were 15/20 restenotic lesions in PCB group and 12/20 in CBA group. In 25/40 cases, patients had an ipslateral catheter insertion in the past. Primary endpoint was clinically-assessed intervention-free period (IFP) of the treated segment at 6 months, while secondary endpoints included complication rates during follow-up period and identification of factors influencing IFP.

RESULTS

Median IFP was significantly better in PCB group (PCB group: 179 days, vs CBA group: 124.5 days, P = .026). Mean follow-up period was 180 days (range, 5-479). There was no significant difference between AVGs and AVFs (P = .17), treatment of de novo vs restenotic lesions (P = .33), or prior presence of catheter insertion (P = .21). No complications were observed. In restenotic lesions in PCB group, longitudinal comparison between treatments also showed a significant difference in favor of PCB treatment (median IFP in PCB* group 177 vs 91 days in CBA* group; P = .01).

CONCLUSIONS

In this prospective study, PCB had significantly better results compared with CBA for the treatment of symptomatic central venous stenosis in dialysis access. Retrospective longitudinal comparison of treatments in the same patients also showed a significant difference in favor of PCBs.

Biomaterial-Based Approaches to Address Vein Graft and Hemodialysis Access Failures

Veins used as grafts in heart bypass or as access points in hemodialysis exhibit high failure rates, thereby causing significant morbidity and mortality for patients. Interventional or revisional surgeries required to correct these failures have been met with limited success and exorbitant costs, particularly for the US Centers for Medicare & Medicaid Services. Vein stenosis or occlusion leading to failure is primarily the result of neointimal hyperplasia. Systemic therapies have achieved little long-term success, indicating the need for more localized, sustained, biomaterial-based solutions. Numerous studies have demonstrated the ability of external stents to reduce neointimal hyperplasia. However, successful results from animal models have failed to translate to the clinic thus far, and no external stent is currently approved for use in the US to prevent vein graft or hemodialysis access failures. This review discusses current progress in the field, design considerations, and future perspectives for biomaterial-based external stents. More comparative studies iteratively modulating biomaterial and biomaterial-drug approaches are critical in addressing mechanistic knowledge gaps associated with external stent application to the arteriovenous environment. Addressing these gaps will ultimately lead to more viable solutions that prevent vein graft and hemodialysis access failures.

Comparison of Open-Cell Stent and Closed-Cell Stent for Treatment of Central Vein Stenosis or Occlusion in Hemodialysis Patients

Background

Central vein stenosis or occlusion is a common complication that can lead to significant morbidity and dysfunction of access in the hemodialysis patient. More lesions can develop over time, and preserving access becomes a challenge as life expectancy of the hemodialysis patient increases.

Objectives

The goal was to compare long-term results and determine the outcomes of open-cell stent versus closed-cell stent for central vein stenosis or occlusion in hemodialysis patients.

Patients and Methods

From 1997 to 2015, in 401 hemodialysis patients, stent placement for central vein stenosis or occlusion was performed if balloon angioplasty was unsatisfactory, due to elastic recoil or occurrence of restenosis within 3 months. When thrombus was present, primary stenting was performed. A total of 257 open-cell stents and 144 closed-cell stents were used. Angiographic findings including lesion site, central vein stenosis or occlusion, and presence of thrombosis and complication were evaluated. Primary patency rate and mean patency rate of the stent were compared between two stent groups by Kaplan-Meier survival analysis.

Results

For the open-cell stent group, 159 patients were diagnosed as central vein stenosis and 98 were occlusion. For the closed-cell stent group, 78 were stenosis and 66 were occlusion. There were two complications for central migration and two for procedure-related vein rupture. Open-cell stents and closed-cell stents had mean patency rates of 10.9 ± 0.80 months and 8.5 ± 10.87 months, respectively (P = 0.002).

Conclusion

The open-cell stent is effective and its performance is higher than that obtained with the closed-cell stent for treating central vein stenosis or occlusion in hemodialysis patients.

Stenting of the Brachiocephalic Vein Following Occlusion After Coronary Artery Bypass Surgery

We describe a case of left arm swelling over nine months post coronary artery bypass grafting (CABG), due to occlusion of the left brachiocephalic vein. The patient's perioperative course, diagnosis, and management of this complication are presented. doi: 10.1111/jocs.12765 (J Card Surg 2016;31:432-434).

Endovascular treatment of central venous obstruction as a complication of prolonged hemodialysis - Preliminary experience in a tertiary care center

Background:

Central venous disease is a serious complication in patients undergoing hemodialysis, often presenting with symptoms of venous hypertension. Treatment is aimed to provide symptomatic relief and to maintain hemodialysis access site patency.

Aim:

To describe our initial experience in the endovascular treatment of central venous stenosis or obstruction in patients undergoing hemodialysis.

Settings and Design:

This was a retrospective study carried out in a tertiary care center. Study duration was 24 months. Follow-up was variable.

Materials and Methods:

Eleven patients of chronic renal failure undergoing hemodialysis presented with central vein stenosis or obstruction having ipsilateral vascular access, between July 2012 and July 2014. All the patients underwent endovascular treatment and were analyzed retrospectively.

Results and Conclusion:

A total of 11 patients (4 male and 7 female) underwent 18 interventions for 13 stenotic segments during a time period of 2 years. Eight stenotic segments were in brachiocephalic vein, three in subclavian vein, and two in axillary veins. The technical success rate for endovascular treatment was 81.8%. Two patients underwent percutaneous transluminal angioplasty (PTA) alone and presented with restenosis later. Balloon angioplasty followed by stenting was done in seven patients, two of which required reintervention during follow-up. We found endovascular treatment safe and effective in treating central venous disease.

Endovascular interventions for central vein stenosis

Central vein stenosis is common because of the placement of venous access and cardiac intravascular devices and compromises vascular access for dialysis. Endovascular intervention with angioplasty and/or stent placement is the preferred approach, but the results are suboptimal and limited. Primary patency after angioplasty alone is poor, but secondary patency can be maintained with repeated angioplasty. Stent placement is recommended for quick recurrence or elastic recoil of stenosis. Primary patency of stents is also poor, though covered stents have recently shown better patency than bare metal stents. Secondary patency requires repeated intervention. Recanalization of occluded central veins is tedious and not always successful. Placement of hybrid graft-catheter with a combined endovascular surgical approach can maintain patency in many cases. In the presence of debilitating symptoms, palliative approach with endovascular banding or occlusion of the access may be necessary. Prevention of central vein stenosis is the most desirable strategy.

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.

Wandering stent within the pulmonary circulation

To present a case of a wandering stent within the pulmonary circulation that was managed conservatively with the "wait-and-see" strategy. Accidental dislodgement of a left brachiocephalic vein stent into the left lower lobe pulmonary artery occurred in an 83-year-old patient suffering from end-stage renal disease during placement of a left jugular vein catheter. The following day, a second X-ray revealed migration of the stent from the left to the right lower lobe pulmonary artery. Our patient was managed conservatively with low-molecular-weight heparin and was discharged on clopidogrel. The patient remained asymptomatic with regard to the migrated stent for four and a half years and died of old age. This is the first case of a wandering stent within the pulmonary circulation reported in the literature, supporting the "wait-and-see" policy in the management of such patients.

Treatment of hemodialysis vascular access arteriovenous graft failure by percutaneous intervention

A patent vascular access is the lifeline of end-stage renal disease patients depending on hemodialysis treatment. Once a functioning vascular access has been established, maintaining its patency is of utmost importance. During the last decades percutaneous techniques became increasingly important for the treatment of hemodialysis vascular access graft failure. In this review, the role of percutaneous balloon angioplasty and stent implantation is evaluated for different clinical scenarios, based on the available evidence.

Central vein stenosis

Central vein stenosis (CVS) is commonly seen in patients receiving hemodialysis through an arteriovenous access, threatening the usability of arteriovenous access for dialysis. Subclavian and internal jugular catheters are prime reasons for the development of CVS, especially in the setting of long-term use of multiple catheters. CVS related to cardiac rhythm devices also is seen frequently. Idiopathic CVS can be encountered, although it is less common. Clinical features ultimately become sufficiently prominent to prompt angiographic evaluation. CVS should be evaluated carefully because management must be individualized. The primary method for treatment of CVS is endovascular intervention, including angioplasty and stent placement, whereas surgical options should be pursued in only refractory cases due to the invasiveness of the intervention. Early referral of patients for chronic kidney disease care; timely discussion of kidney replacement modality choices, including nonhemodialysis options such as peritoneal dialysis and kidney transplantation; placement of arteriovenous access prior to the onset of dialysis; and avoidance of catheters and other central vein instrumentation will prevent the development of CVS in most patients with kidney disease.

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.

Killing Two Birds with One Stone: Subclavian Vein Bypass Graft for Relief of Venous Obstruction and Haemodialysis Access

Subclavian and brachio-cephalic vein stenosis or occlusion occurs, most commonly, as an iatrogenic complication of the placement of central venous catheter. This occurrence can cause ipsilateral arm swelling in a newly-created arteriovenous fistula (AVF). Critical central vein stenoses are often successfully managed by endovascular approach; occasionally, complete occlusion with symptomatic severe arm swelling and pain that does not respond to angioplasty requires ligation of the dialysis access. We report successful surgical management of an end-stage-renal-failure (ESRF) patient with symptomatic subclavian vein occlusion refractory to angioplasty in an ipsilateral arm with an existing functional brachio-basilic transposition arteriovenous fistula by performing a basilic to internal jugular vein (IJV) bypass graft, relieving both the arm swelling and salvaging the existing vascular access for future haemodialysis.

Efficacy of SMART Stent Placement for Salvage Angioplasty in Hemodialysis Patients with Recurrent Vascular Access Stenosis

Vascular access stenosis is a major complication in hemodialysis patients. We prospectively observed 50 patients in whom 50 nitinol shape-memory alloy-recoverable technology (SMART) stents were used as salvage therapy for recurrent peripheral venous stenosis. Twenty-five stents each were deployed in native arteriovenous fistula (AVF) and synthetic arteriovenous polyurethane graft (AVG) cases. Vascular access patency rates were calculated by Kaplan-Meier analysis. The primary patency rates in AVF versus AVG at 3, 6, and 12 months were 80.3% versus 75.6%, 64.9% versus 28.3%, and 32.3% versus 18.9%, respectively. The secondary patency rates in AVF versus AVG at 3, 6, and 12 months were 88.5% versus 75.5%, 82.6% versus 61.8%, and 74.4% versus 61.8%, respectively. Although there were no statistically significant difference in patency between AVF and AVG, AVG showed poor tendency in primary and secondary patency. The usefulness of SMART stents was limited in a short period of time in hemodialysis patients with recurrent vascular access stenosis.

Stent-Grafts Improve Secondary Patency of Failing Hemodialysis Grafts

Purpose

Failing hemodialysis grafts continue to pose a challenge in the care of patients with end-stage renal disease (ESRD). We review our experience using percutaneous stent-grafts for the treatment of venous outflow stenosis and occlusion in order to assess their efficacy in nonautologous graft salvage.

Methods

This is a retrospective review of patients treated with percutaneous Viabahn® stent-grafts for failing hemodialysis arteriovenous grafts (AVGs), between 6/2006 and 12/2009. All stent-grafts were deployed across the venous anastomosis to address the outflow obstruction. Patency and re-intervention rates were estimated using Kaplan-Meier analysis.

Results

Twenty patients had stent-grafts placed. Successful stent-grafting was defined as <30% residual stenosis and the ability to dialyze through the graft post-treatment. Technical success for stent-grafting was 100%. Median follow-up was 23 months (range 3 to 37 months). Stent-graft patency at 6 months: 94.7%, 12 months: 94.7%, 18 months: 82.1%, 24 months: 82.1%, 36 months: 82.1%. Freedom from re-intervention was 69% at 24 months and 50% at 36 months. Two AVGs failed and had to be removed without further interventions, because of complete occlusion and infection. Two patients (10%) required re-intervention for arterial inflow stenosis. One patient (5%) required balloon angioplasty and stenting of stenosis distal to the stent-graft. One patient (5%) developed in-stent stenosis and was treated with placement of a new stent. Graft salvage rate was 80% at 36 months.

Conclusions

Stent-grafts can be successfully used to improve freedom from re-intervention rates and overall patency rates of failing AVGs.

Increased plasma chymase concentration and mast cell chymase expression in venous neointimal lesions of patients with CKD and ESRD

The underlying inflammatory component of chronic kidney disease may predispose blood vessels to intimal hyperplasia (IH), which is the primary cause of dialysis access failure. We hypothesize that vascular pathology and markers of IH formation are antecedent to arteriovenous (AV) fistula creation. Blood, cephalic, and basilic vein segments were collected from predialysis chronic kidney disease (CKD) patients with no previous AV access and patients with end-stage renal disease (ESRD). Immunohistochemistry was performed with antibodies against mast cell chymase, transforming growth factor-beta (TGF-β) and interleukin-6 (IL-6), which cause IH. Plasma chymase was measured by ELISA. IH was present in 91% of CKD and 75% of ESRD vein segments. Chymase was abundant in vessels with IH, with the greatest expression in intima and medial layers, and virtually absent in the controls. Chymase colocalized with TGF-β1 and IL-6. Plasma chymase concentration was elevated up to 33-fold in patients with CKD versus controls and was associated with increased chymase in vessels with IH. We show that chymase expression in vessels with IH corresponds with plasma chymase concentrations. As chymase inhibition attenuates IH in animal models, and we find chymase is highly expressed in IH lesions of patients with CKD and ESRD, we speculate that chymase inhibition could have therapeutic value in humans.

Long-term results of stent-graft placement to treat central venous stenosis and occlusion in hemodialysis patients with arteriovenous fistulas

PURPOSE

To determine the effectiveness of stent-grafts for the treatment of central venous disease in hemodialysis patients with functioning arteriovenous (AV) fistulas.

MATERIALS AND METHODS

Between October 2004 and March 2010, 42 VIABAHN stent-grafts were deployed in central veins of 30 patients (16 men, 14 women; mean age 60 y) with functioning AV fistulas and central venous disease that did not respond to percutaneous transluminal angioplasty (PTA). Eighteen patients had central vein stenosis and 12 had occlusion. Previous PTA and/or bare metal stent placement had been performed in 23 patients (77%). Surveillance was carried out at 3, 6, 9, 12, 18, and 24 months with diagnostic fistulography. The mean follow-up was 705 days (range, 66-1,645 d). Statistical analysis included Kaplan-Meier and log-rank studies.

RESULTS

Technical success rate was 100%. Primary patency rates were 97%, 81%, 67%, and 45% at 3, 6, 12, and 24 months, respectively. Primary assisted patency rates were 100%, 100%, 80%, and 75% at 3, 6, 12, and 24 months, respectively. Patients without previous procedures had significantly shorter times to repeat intervention (P = .018) than those who had undergone PTA or bare metal stent placement previously. Patients with occlusive lesions had a significantly shorter primary patency interval (P = .05) than patients with stenoses. Occluded veins were more likely to require further stent-grafts (P = .02). Twelve patients required further stent-grafts to maintain patency. There was one minor complication.

CONCLUSIONS

Stent-graft placement to treat central venous disease in hemodialysis patients with autogenous AV fistulas is safe and effective if PTA fails to maintain luminal patency.

Central venous disease in hemodialysis patients: prevalence, etiology and treatment

A common problem in the management of hemodialysis patients is central venous occlusive disease. There has been extensive literature on the treatment of this important and prevalent problem. Treatment options to date include percutaneous balloon angioplasty, bare metal stents and surgical bypass. Unfortunately, all the available treatment options have poor long-term patency, requiring repetitive intervention. More recently, covered stents have been mentioned in the literature for the treatment of central venous stenosis and obstruction. There is very little data to date on this technology, and further randomized controlled trials will be needed to compare the efficacy of percutaneous balloon angioplasty, bare metal stents and covered stents. It appears prevention of this difficult problem is paramount, by limiting venous access or intervention of the central venous system.

Review of central venous disease in hemodialysis patients

A common problem in the management of patients who are undergoing hemodialysis is central venous occlusive disease. There has been extensive literature on the treatment of this important and prevalent problem. Treatment options to date include percutaneous balloon angioplasty, bare metal stents, and surgical bypass. Unfortunately, all the available treatment options have poor long-term patency, requiring repeated interventions. More recently, covered stents have been mentioned in the literature for the treatment of central venous stenosis and obstruction. There are very few data to date on this technology, and further randomized controlled trials will be needed to compare the efficacy of percutaneous balloon angioplasty, bare metal stents, and covered stents. It appears that it is of paramount importance to prevent this difficult problem by limiting access to, or intervention in, the central venous system.

Central vein stenosis: current concepts

Central vein stenosis (CVS) is a common complication of the central venous catheter (CVC) placement. The prevalence of CVS has mostly been studied in those who present with symptoms such as swelling of the extremity, neck and breast. CVS compromises arteriovenous access and can be resistant to treatment. A previous history of CVC placement is the most important risk factor for the development of CVS later. Pacemaker and defibrillator wires are associated with a high incidence of CVS. Increasingly liberal use of peripherally inserted central catheters (PICC) is likely to increase the incidence of CVS. The trauma and inflammation related to the catheter placement is thought to result in microthrombi formation, intimal hyperplasia and fibrotic response, with development of CVS. Treatment of CVS by endovascular procedures involves angioplasty of the stenosis. An elastic or recurrent stenosis may require a stent placement. The long-term benefits of the endovascular procedures, although improved with newer technology, remain modest. Surgical options are usually limited. Future studies to explore the pathogenesis and the use of novel therapies to prevent and treat CVS are needed. The key to reducing the prevalence of CVS is in reducing CVC placement and placement of arteriovenous accesses prior to initiating dialysis. Early referral of the patients to the nephrologists by the primary care physicians is important. Timely vein mapping and referral to the surgeon for fistula creation can obviate the need for a CVC and decrease incidence of CVS.

Central venous obstruction management

A major challenge in the management of hemodialysis patients is central venous stenosis and obstruction. Placement of central venous catheters has been shown to result in a high incidence of central venous stenosis or obstruction. There has been extensive literature on the treatment of this important and prevalent problem. Treatment options include percutaneous balloon angioplasty and bare metal stents. Unfortunately, all the available treatment options have variable rates of patency, requiring repeated intervention. More recently, covered stents have been mentioned in the literature for the treatment of central venous stenosis and obstruction. There is very little data to date, and further randomized controlled trials will be needed to compare the efficacy of percutaneous balloon angioplasty, bare metal stents, and covered stents. It appears prevention of this difficult problem is paramount, by limiting use of central venous catheters.

Stent placement in hemodialysis access: historical lessons, the state of the art and future directions

Vascular access stenosis in patients undergoing chronic hemodialysis is a major issue that is associated with increased morbidity, mortality, and cost of medical care. Recent data have emphasized that endovascular stents could be used in the treatment of central as well as peripheral stenotic lesions. In general, a peripheral or central vein lesion that is elastic or recurs within a three-month period after an initially successful balloon angioplasty or a stenosis where surgical revision is not possible are some indications for intravascular stent placement. Recent reports have expanded the role of stents in the management of pseudoaneurysms associated with dialysis access. In this context, the utilization of these devices must take into account a fair comparison with the traditional (surgical) approaches regarding effectiveness as well as costs. This report describes the role of stents in arteriovenous dialysis access. In addition, some of the recent advances in the structure and complicating issues such as stent fracture, migration, and infection, as well cannulation through the stent, are discussed.

Use of nitinol stents following recanalization of central venous occlusions in hemodialysis patients

PURPOSE

To retrospectively review the patency of endovascular interventions with nitinol stent placement for symptomatic central venous occlusions in hemodialysis patients.

METHODS

A retrospective review of all patients who underwent endovascular interventions for dysfunctional hemodialysis grafts and fistulas was performed from April 2004 to August 2006. A total of 6 patients presented with arm and/or neck and facial swelling and left brachiocephalic vein occlusion. The study group consisted of 3 men and 3 women with a mean age of 79.5 years (SD 11.2 years). Of these 6 patients, 1 had a graft and 5 had fistulas in the left arm. The primary indication for nitinol stent placement was technical failure of angioplasty following successful traversal of occluded central venous segments. Patency was assessed from repeat fistulograms and central venograms performed when patients redeveloped symptoms or were referred for access dysfunction determined by the ultrasound dilution technique. No patients were lost to follow-up.

RESULTS

Nitinol stent placement to obtain technically successful recanalization of occluded venous segments was initially successful in 5 of 6 patients (83%). In 1 patient, incorrect stent positioning resulted in partial migration to the superior vena cava requiring restenting to prevent further migration. Clinical success was observed in all patients (100%). Over the follow-up period, 2 patients underwent repeat intervention with angioplasty alone. Primary patency was 83.3% (95% CI 0.5-1.2) at 3 months, and 66.7% at 6 and 12 months (0.2-1.1, 0.1-1.2). Secondary patency was 100% at 12 months with 3 patients censored over that time period. Mean primary patency was 10.4 months with a mean follow-up of 12.4 months. No complications related to recanalization of the occluded central venous segments were observed.

CONCLUSION

Our initial experience has demonstrated that use of nitinol stents for central venous occlusion in hemodialysis patients is associated with good mid-term patency and may exceed historical observations with prior use of Wallstents.

Long-term outcomes of primary angioplasty and primary stenting of central venous stenosis in hemodialysis patients

INTRODUCTION

Central (superior vena cava, brachiocephalic, or subclavian) venous stenoses are a major impediment to long-term arteriovenous access in the upper extremities. The optimal management of these stenoses is still undecided. The purpose of this study was to determine the outcomes of primary angioplasty (PTA) vs primary stenting (PTS) in a dialysis access population at a tertiary referral academic medical center.

METHODS

A database of consecutive hemodialysis patients undergoing endovascular treatment for central venous stenosis was developed for the period 1995 through 2003. This database was retrospectively reviewed. Vessels exposed to either primary high-pressure balloon angioplasty or primary stenting were examined. Vessels undergoing stenting after failed or suboptimal angioplasty were defined as failures at the time of stenting despite the potential continued patency upon completion of stenting. Kaplan-Meier survival analyses were performed to assess time-dependent outcomes. Cox proportional hazards analysis was performed for time-dependent variables. Data are presented as mean +/- standard deviation where appropriate.

RESULTS

PTS was used to treat 26 patients (35% male; average age, 57 +/- 15 years) with 26 central venous stenoses, and 47 patients (45% male; average age, 57 +/- 18 years) with 49 central venous stenoses were treated with PTA. The PTS group underwent 71 percutaneous interventions per stenosis (average, 2.7 +/- 2.4 interventions), and the PTA group underwent 98 interventions per stenosis (average, 2.0 +/- 1.6 interventions). The PTS group hemodialysis access site was an average of 1.0 +/- 1.3 years old at the time of the initial intervention, and the hemodialysis access in the PTA group was an average of 1.1 +/- 1.2 years old. Primary patency was equivalent between groups by Kaplan-Meier analysis, with 30-day rates of 76% for both groups and 12-month rates of 29% for PTA and 21% for PTS (P = .48). Assisted primary patency was also equivalent (P = .08), with a 30-day patency rate of 81% and 12-month rate of 73% for the PTA group, vs PTS assisted patency rates of 84% at 30 days, and 46% at 12 months. Ipsilateral hemodialysis access survival was equivalent between groups.

CONCLUSIONS

Endovascular therapy with PTA or PTS for central venous stenosis is safe, with low rates of technical failure. Multiple additional interventions are the rule with both treatments. Although neither offers truly durable outcomes, PTS does not improve on the patency rates more than PTA and does not add to the longevity of ipsilateral hemodialysis access sites.

Central vein stenosis: a nephrologist's perspective

Central vein stenosis is commonly associated with placement of central venous catheters and devices. Central vein stenosis can jeopardize the future of arteriovenous fistula and arteriovenous graft in the ipsilateral extremity. Occurrence of central vein stenosis in association with indwelling intravascular devices including short-term, small-diameter catheters such as peripherally inserted central catheters, long-term hemodialysis catheters, as well as pacemaker wires, has been recognized for over two decades. Placement of multiple catheters, longer duration, location in subclavian vein, and placement on the left-hand side of neck seem to predispose to the development of central vein stenosis. Endothelial injury with subsequent changes in the vessel wall results in development of microthrombi, smooth muscle proliferation, and central vein stenosis. Central vein stenosis is often asymptomatic in nondialysis patients, but can result in edema of ipsilateral extremity and breast when challenged by increased flow from an arteriovenous fistula or arteriovenous graft. Bilateral central vein stenosis or superior vena cava stenosis can produce a clinical picture of superior vena cava syndrome, associated with engorgement of face and neck. Endovascular interventions are the mainstay of management of central vein stenosis. Percutaneous angioplasty and stent placement for elastic and recurring lesions can restore the functionality of the vascular access, at least temporarily. Frequent or multiple interventions are usually required. In recalcitrant cases, surgical bypass of the obstruction is an option. In resistant cases with severe symptoms, occlusion of the functioning vascular access will usually provide relief of symptoms. Further study of mechanisms of development of central vein stenosis and search for a targeted therapy is likely to lead to better ways of managing central vein stenosis. Prevention of central vein stenosis is the key to avoid access failure and other complications from central vein stenosis and relies upon avoidance of central vein stenosis placement and timely placement of arteriovenous fistula in prospective dialysis patient.