Salvage Treatment for Venous Aneurysm Complicating Vascular Access Arteriovenous Fistula: Use of an Exoprosthesis to Reinforce the Vein after Aneurysmorrhaphy

Pave and Pop: A novel addition to the endovascular treatment of hemodialysis access aneurysms

BACKGROUND

Hemodialysis access sites can be complicated by both true and false aneurysms with significant potential morbidity. Aneurysms have traditionally been treated by a variety of surgical methods. Less commonly, endovascular treatment with stent graft placement has been used as an alternative to open surgery.

METHODS

Four patients with symptomatic aneurysmal disease in the hemodialysis access site were treated. All patients had stent grafts (SGs) placed across the diseased segment. Once the diseased segment was excluded, blood was drained from the aneurysm with an 18 g needle. All patients were seen in clinic at 1- and 3-months post procedure.

RESULTS

All patients were able to receive adequate hemodialysis post procedure. Two patients were cannulated via the SG after 1 month. No aneurysm refilling was seen. No SG infections or fractures were seen.

CONCLUSION

A novel addition to the endovascular treatment of aneurysmal disease in hemodialysis patients is described, that both excludes the aneurysm and drains it, providing improvement in the aesthetic appearance of the access site.

External Support of Autologous Internal Jugular Vein Grafts with FRAME Mesh in a Porcine Carotid Artery Model

BACKGROUND

Autologous vein grafts are widely used for bypass procedures in cardiovascular surgery. However, these grafts are susceptible to failure due to vein graft disease. Our study aimed to evaluate the impact of the latest-generation FRAME external support on vein graft remodeling in a preclinical model.

METHODS

We performed autologous internal jugular vein interposition grafting in porcine carotid arteries for one month. Four grafts were supported with a FRAME mesh, while seven unsupported grafts served as controls. The conduits were examined through flowmetry, angiography, macroscopy, and microscopy.

RESULTS

The one-month patency rate of FRAME-supported grafts was 100% (4/4), whereas that of unsupported controls was 43% (3/7, Log-rank p = 0.071). On explant angiography, FRAME grafts exhibited significantly more areas with no or mild stenosis (9/12) compared to control grafts (3/21, p = 0.0009). Blood flow at explantation was higher in the FRAME grafts (145 ± 51 mL/min) than in the controls (46 ± 85 mL/min, p = 0.066). Area and thickness of neo-intimal hyperplasia (NIH) at proximal anastomoses were similar for the FRAME and the control groups: 5.79 ± 1.38 versus 6.94 ± 1.10 mm2, respectively (p = 0.558) and 480 ± 95 vs. 587 ± 52 μm2/μm, respectively (p = 0.401). However, in the midgraft portions, the NIH area and thickness were significantly lower in the FRAME group than in the control group: 3.73 ± 0.64 vs. 6.27 ± 0.64 mm2, respectively (p = 0.022) and 258 ± 49 vs. 518 ± 36 μm2/μm, respectively (p = 0.0002).

CONCLUSIONS

In our porcine model, the external mesh FRAME improved the patency of vein-to-carotid artery grafts and protected them from stenosis, particularly in the mid regions. The midgraft neo-intimal hyperplasia was two-fold thinner in the meshed grafts than in the controls.

Salvage Aneurysmorrhaphy as an Adaptable and Still Pertinent Technique in the Management of Challenging True Aneurysms of Arteriovenous Fistulas: A Case Series of Different Variations, With Illustrative Surgical Pictures

Introduction

Aneurysmorrhaphy, described as reduction aneurysmoplasty, partial aneurysmectomy, or vessel wall recalibration, can be considered a suitable surgical plan for true aneurysms of arteriovenous fistulas (AVFs), allowing for a dynamic approach to reconstruction of aneurysmal AVFs of different severities, ensuring salvage of the native access.

Report

Six challenging cases of AVF aneurysms are presented, some with extremely dilated and tortuous megafistulas, for which three surgical technique variations were performed. The patients had a mean age of 59.2 years, 50% were female, with brachiocephalic (n = 5, 83.3%) or brachiobasilic (n = 1, 16.7%) AVFs. The fistulas were created an average of 4.67 years previously, and the aneurysms had an average maximum diameter of 37.5 mm (range 25-60 mm). Surgical indications were rupture risk, thrombosis, or outflow stenosis compromising haemodialysis, infections, and concerns for quality of life (affected by post-puncture bleedings, disfiguring aesthetics, pain, and discomfort). The surgical techniques were simple aneurysmorrhaphy (n = 3, 50%), aneurysmorrhaphy with partial excision of aneurysmal segment with end to end anastomosis of venous ends (n = 2, 33.3%), and aneurysmorrhaphy with establishment of new venous outflow (n = 1, 16.7%). All AVFs were patent post-operatively and at follow up (mean 5.6 months, median one month). Haemodialysis was resumed through the AVFs at a mean of 2.17 weeks post-operatively, with placement of an alternative route for haemodialysis in the meantime. No patients experienced post-operative complications.

Discussion

Experience with the more challenging cases shows that aneurysmorrhaphy can still be considered an acceptable, flexible, and pertinent method for salvage of megafistulas, giving the surgeon the much needed versatility to adapt to anatomical and pathological variations, with high patency rates and minimal complications, especially when other treatment options are not possible in complicated cases. AVF salvage through aneurysmorrhaphy allows for a dynamic approach to the reconstruction of severely tortuous, dilated veins, ensuring patency of the native AVF.

End-to-end anastomosis as a superior repair type to prevent recurrence of arteriovenous fistula aneurysms and improve patency outcomes

BACKGROUND

Arteriovenous fistulae (AVF) complicated by aneurysms are repaired through several mechanisms. Little is known about risk factors for aneurysm recurrence or the efficacy of subsequent repair of recurring aneurysms.

METHODS

About 291 patients underwent AVF aneurysm repair between 2009 and 2019 at a large urban medical center. Patients who underwent staged repair, had a primary graft with pseudoaneurysm, were status-post kidney transplant, or using other dialysis access at the time of repair were excluded. One hundred sixty-two patients were included in the study, of which 52 developed a secondary aneurysm. Chi-square and t-test analyses were used to compare demographics. Multivariate logistic regression was used to examine independent risk factors for aneurysm recurrence. Of the 52 patients with recurrent aneurysms, 41 were repaired again. Patency was examined for each group 1 year postoperatively.

RESULTS

Patients without secondary aneurysms were more likely to have a Charlson Comorbidity Index score ⩾5 (p = 0.045). Males were 2.8 times more likely to develop a secondary aneurysm compared to females (p = 0.023). Patients who underwent elective compared to emergent or urgent surgery for primary aneurysms were significantly less likely to recur (OR = 0.222; p = 0.016). Primary aneurysms repaired by end-to-end anastomosis, compared to aneurysmorrhaphy or graft, were significantly less likely to recur (OR = 0.239; p = 0.041). Among patients with secondary aneurysms, those repaired via end-to-end anastomosis had a significantly higher primary patency rate 1 year postoperatively (p = 0.024). Secondary aneurysm repairs exhibited 1-year primary and secondary patency rates of 51.2% and 82.9%, respectively.

CONCLUSIONS

End-to-end anastomosis reduces risk of recurrence and demonstrates superior patency rates when repairing recurrent aneurysms. It remains unclear why some patients are prone to aneurysm recurrence, however continued attempts to repair existing vascular access are proven to be successful.

Management of an aneurysmal arteriovenous fistula in kidney transplant recipients

Aneurysms remain the most common complication of an arteriovenous fistula created for dialysis access. The management of an aneurysmal arteriovenous fistula (AAVF) in kidney transplant recipients remains contentious with a lack of clear clinical guidelines. Recipients of a functioning graft do not require the fistula for dialysis access, however risk of graft failure and needing the access at a future date must be considered. In this review we outline the current evidence in the assessment and management of a transplant recipient with an AAVF. We will describe our recommended five-step approach to assessing an AAVF in transplant patients; 1.) Define AAVF 2.) Risk assess AAVF 3.) Assess transplant graft function and future graft failure risk 4.) Consider future renal replacement therapy options 5.) Vascular mapping to assess future vascular access options. Then we will describe the current therapeutic options and when they would most appropriately be employed.

Treatment of arteriovenous fistula with aneurysm using the forearm branch of the cephalic vein as a candidate vessel: A case report

BACKGROUND

Arteriovenous fistula (AVF) is the preferred vascular access for hemodialysis patients due to its better patency rates and fewer complications than other access types. However, some complications related to AVF could not be ignored, including swollen hands and an aneurysm. Although a patient could not continue hemodialysis, it might threaten the patient's life if the rupture of the aneurysm is not immediately treated by the surgeon. A report of using the cephalic vein branch to treat this complication is uncommon.

CASE PRESENTATION

Herein, we present a case of a 42-year-old man in whom an AVF with an aneurysm was successfully treated using the excess cephalic vein branch. This method is a simple and effective intervention for managing aneurysm-associated complications. Additionally, this approach helps maintain the benefits of autogenous access while conserving future dialysis sites.

CONCLUSION

The surgery was effective and safe for this kind of complication with swollen hands and aneurysm. Using the excess cephalic vein branch could reconstruct the AVF.

Revision of Aneurysmal Arteriovenous Access with Immediate Use Graft Is Safe and Avoids Prolonged Use of Tunneled Hemodialysis Catheters

INTRODUCTION

Aneurysmal AVF can pose a difficult treatment dilemma for the vascular surgeon. Prolonged tunneled dialysis catheters (TDC) in patients requiring long-term dialysis are associated with significantly increased mortality compared to arteriovenous fistulas (AVF). We aimed to elucidate the outcomes of aneurysmal AV access revision with aneurysm resection and Artegraft® (LeMaitre, New Brunswick, NJ) Collage Vascular Graft placement to avoid prolonged use of TDCs.

METHODS

We reviewed all patients with aneurysmal AV access in which the access was revised with aneurysm resection and jump graft placement at a single institution from 2018 to 2021. Outcomes were time to cannulation, reintervention rates, time to reintervention and patency (primary, primary assisted and secondary). Patency rates were estimated with Kaplan-Meier Survival analysis.

RESULTS

A total of 51 revised aneurysmal AV access in 51 patients were studied, of which 23.5% (n=12) had perioperative TDC placement. Three patients were done for emergent bleeding. The cohort was 62.8% male (n=32) with a median age of 58 years (IQR: 49-67). Most patients had brachiocephalic AVF (n=37 [72.6%]). Median follow up time was 280 days. Median time to cannulation was 2 days. Time to cannulation was significantly longer in patients with perioperative TDC as compared with those without TDC (24 days vs 2 days, P<0.001). Reintervention was required in 41.2% of patients (n=21), at median time of 47 days. At 30, 90, 180, and 365 days, primary patency rates were 84.3%, 78.3%, 66.6%, and 54.9%; primary assisted patency rates were 94.1%, 88.1%, 79.4%, and 79.4% and secondary patency rates were 100%, 97.8%, 91.6% and 91.6% respectively.

CONCLUSIONS

Revision of aneurysmal AV access (urgent or elective) with Artegraft as jump graft is safe, with acceptable short and mid-term patency results. This allows dialysis patients to continue to have a functional access, decreasing the need for a tunneled catheter and reducing the associated risk of sepsis and increased mortality. This should be considered for all patients with aneurysmal, dysfunctional fistulas to maintain AV access and avoid TDC placement.

Surgical management of a giant venous aneurysm in an autogenous arteriovenous fistula with the vessel loop shoelace technique for wound closure: A case report

RATIONALE

Giant venous aneurysm (GVA) is a complication of chronic arteriovenous fistula (AVF). The risks of thrombosis, rupture, and massive hemorrhage increase with the increasing size of GVA; therefore, GVA requires treatment. However, the optimal timing and treatments are yet to be established.

PATIENT CONCERNS

A 51-year-old male patient who had been undergoing hemodialysis for 10 years using a left radio-cephalic AVF presented to the hospital with an enormous venous aneurysm.

DIAGNOSIS

Physical examination and ultrasound revealed a GVA in the AVF.

INTERVENTION

The aneurysm was resected, and autogenous AVF was concomitantly formed using the basilic vein. The large wound caused by the removed aneurysm defect was closed using the vessel loop shoelace technique.

OUTCOMES

The wound healed completely, and the patient has been undergoing hemodialysis using the autogenous AVF created during the surgery for 15 months since then.

LESSONS

Surgical treatment should be considered for symptomatic GVA. Concomitant aneurysm resection and autogenous AVF formation using the basilic vein may be performed, and the resulting large wound can be closed with the vessel loop shoelace technique to facilitate healing.

[Surgical treatment of true aneurysms of permanent vascular access]

Analyzed herein are the results of surgical treatment of true diffuse aneurysms of the permanent vascular access in 44 patients. Of these, there were 29 men and 15 women, mean age 48.1±2.3 years (19-78 years). The average time having elapsed since the formation of the native access was 109.4±9.5 months (12-276, median - 108 months). The indications for surgical treatment were as follows: haemorrhage including recurrent bleedings (3), thrombosis of the permanent vascular access (26), its dysfunction (5), high flow syndrome (3), large-size aneurysm with disordered function of the limb, pain syndrome or a pronounced cosmetic defect (7). In 14 cases, reconstruction was not performed. We carried out ligating operations, in some instances with partial removal of the aneurysm and establishing a new vascular access. 3 patients underwent resection of the aneurysm with replacement by a graft. In the remote period 1 patient at 46 months developed infection of the prosthesis, resulting in loss of the access. Follow up of the remaining 2 patients demonstrated satisfactory function of the vascular access at 6 and 60 months. 16 patients were subjected to total plasty of the aneurysm using autotissues. On a cylindrical template measuring 6 mm in diameter after dissection of excessive tissues along the posterior wall of the vein, an uninterrupted suture was formed followed by placing the formed transplant into a new bed. 11 patients underwent the operation according to the analogous technique, but the formed autotransplant was reinforced with a thin-wall exoprosthesis made of polytetrafluoroethylene up to 0.2-mm thick and 10 mm in diameter ('Ecoflon'). Two (12.5%) of 16 patients subjected to reconstruction of the aneurysm without reinforcement developed haemorrhage in the early postoperative period, and one developed thrombosis thus resulting in loss of the access. In-hospital patency amounted to 81.3%. In plasty with reinforcement, there were no complications in the early postoperative period. Long-term primary patency after total plasty without reinforcement at 1, 3, and 5 years amounted to 68.2±11.8%, 56.8±14.3%, and 22.7±13.7%, respectively, with secondary patency of 68.2±11.8% at the above-mentioned terms. In the majority of patients aneurysmatic transformation of the transplant occurred again in the remote period. Primary patency at 1, 3 and 4 years after plasty with reinforcement amounted to 80.8±12.2%, 80.8±12-2% and 60.6±19.8%, respectively, with the secondary patency rates of 90.9±8.7% at the above mentioned terms.

The Role of Immunosuppressive Therapy in Aneurysmal Degeneration of Hemodialysis Fistulas in Renal Transplant Patients

BACKGROUND

Venous aneurysms are long-term complications of arteriovenous fistula (AVF) for hemodialysis with an estimated incidence rate of around 5-6%. The purpose of our study is to investigate the role of immunosuppressive therapy in the development of AVF aneurysms in renal transplant patients, and to determine whether AVF closure following transplantation is necessary.

METHODS

Forty-six patients with symptomatic venous AVF aneurysms underwent ligation and resection of their fistulas between January 2013 and January 2020. Immunohistochemical expression of CD3, CD4, and CD8 was assessed on the surgical specimens to characterize lymphocytic infiltrate in the aneurysm wall. Patients were subdivided into "Group A"-kidney transplant patients undergoing immunosuppressive therapy which was comprised of 39 patients and "Group B"-patients who had not undergone kidney transplant which was comprised of 7 patients. The 2 groups did not significantly differ in age, sex nor risk factors for aneurysms.

RESULTS

Group A showed a significantly higher aneurysm diameter (P < 0.0001), mean flow (P < 0.0001) and required a longer duration of surgery (P = 0.0007). A CD3+ lymphocytic infiltrate was significantly more common in Group A than in the Group B (90% vs 29%; P < 0.001). No significant differences in localization (adventitia, media or intima) and type (CD4+ vs CD8+) of lymphocytes were found between the 2 groups.

CONCLUSION

AVF venous aneurysms were significantly larger and with a more intense T-lymphocytic infiltrate in patients undergoing immunosuppressive therapy. This finding suggests that immunosuppressive therapy plays a role in aneurysm formation, supporting the need for AVF closure in patients with an estimated low risk of rejection.

[Complications of permanent vascular access for haemodialysis]

Permanent vascular access is the basis of renal replacement therapy by the method of programmed haemodialysis, on whose stable functioning depends the life of patients with end-stage renal disease. At the present time, there is significant deficit of scientific and methodological Russian-language literature on this problem, with no Russian consensus documents concerned. This article is a review of the contemporary world literature dedicated to the problem of permanent vascular access, including currently in force European (2018) and North American (2019) guidelines for good clinical practice, also discussing the problems of strategy and tactics of creating a permanent vascular access, monitoring its dysfunction, pathophysiology of functioning of arteriovenous fistulas. Presented herein are unified approaches to diagnosis and treatment of thrombolytic and haemorrhagic complications associated with the access, as well as local infectious and non-infectious complications. Special attention is paid to indications for the operation and rational therapeutic decision-making.

Upper extremity reconstruction following open surgical repair of giant arteriovenous fistula aneurysm: clinical case and systematic review of the literature

Background:

Nearly 30% of arteriovenous fistulas (AVFs) located in the upper extremity for hemodialysis access result in short- and long-term adverse effects, such as rupture, necessitating emergent surgical management and extensive soft-tissue reconstruction. With this systematic review, we aimed to compile all reported open surgical techniques used for complicated AVF repair in the upper extremity, the respective soft-tissue reconstructive outcomes, and vascular patency rates at final follow-up.

Methods:

Using Ovid Medline/PubMed databases, we conducted a review of the English-language literature on AVF aneurysm surgical management in the upper extremity, filtered for relevance to open surgical technique and outcomes in vascular patency after aneurysmal repair at long-term follow-up (≥6 months postoperatively). We include a detailed case of surgical removal of a giant AVF aneurysm and subsequent flap elevation and reconstruction of the upper extremity.

Results:

Of 150 articles found in the initial search, 19 (from 2010-2017) met inclusion criteria. From the reviewed studies, 675 patients underwent open surgical repair of AVF aneurysm in the upper extremity. Surgical approaches included partial-to-full aneurysm excision, interposition graft, tubularized extracellular matrix, sutured and stapled aneurysmorrhaphy, and stent graft. Rates of vascular patency at repair site ranged from 47% to 100%, with a pooled average of 78% at 6 months or longer postoperatively.

Conclusions:

For plastic and hand surgeons, aneurysmal ligation and excision is feasible even in severe cases and is associated with overall good vascular and soft-tissue reconstructive outcomes in the upper extremity. (www.actabiomedica.it)

Hybrid procedures in the dialysis fistula aneurysm treatment

OBJECTIVES

Dialysis fistula aneurysms are common complications which in selective cases require surgical revision. It is recommended to detect and treat outflow stenosis concurrent with a dialysis fistula aneurysm, but usually, the treatment is divided into two stages - the open and endovascular stages are performed separately. We describe the results of hybrid procedures composed of aneurysm resection and endovascular correction for outflow veins performed for a dialysis fistula aneurysm treatment.

METHODS

From March 2012, we performed hybrid procedures in 28 patients to correct dialysis fistula aneurysms. Patients, dialysis access, operative data, and the results obtained during a median follow-up of 28.5 months were analyzed.

RESULTS

For dialysis fistula aneurysm correction, we performed 27 bypasses and 1 aneurysmorraphy. For outflow vein stenosis correction, we performed standard balloon angioplasty, no stents or stentgraft were used. The average increase in minimal diameter after angioplasty was 135.5% (range 57-275%). The 12- and 24-month primary patency rates of corrected fistulas in the observed group were 92.3% and 80%, respectively. A significant difference in the one-year patency rates between the urgent and planned procedures was observed (81.2% vs. 100%, respectively). No early complications related to endovascular or open procedures were observed. Late complications were observed in seven patients (25%) - mainly thrombosis caused by the recurrence of outflow vein stenosis (six patients, 21.5%), infection, lymphocele, and hematoma (one case of each complication).

CONCLUSIONS

A hybrid procedure for the surgical correction of dialysis fistula aneurysms with the simultaneous correction of outflow pathologies enables effective long-term treatment. The obtained data showed the efficiency and good results of this procedure. Procedures performed for urgent indications significantly increase the risk for later complications, especially fistula thrombosis and loss of dialysis access.

[Conservative aneurysmorrhaphy for hemodialysis arteriovenous fistula]

The aim of this study was to evaluate the results of conservative surgical treatment of the aneurysmal complications of arteriovenous hemodialysis fistulae and to determine the factors predictive of long- and mid-term patency of treated fistulae. The surgical treatment was mainly based on caliber reduction and reconstruction.

METHODS

This was a descriptive retrospective study with a five-year duration, going from January 2013 to December 2018. This study included 40 patients presenting aneurysmal complications of their hemodialysis vascular access who were treated with aneurysmorrhaphy.

RESULTS

The mean age of the aneurysmal-complicated hemodialysis vascular access was 42 months. The indications for treatment were puncture-related difficulties in 42.5% of cases, rapid increase of the aneurysmal diameter in 27.5%, skin thinning in 25% and aneurysmal rupture in 5%. The mean aneurysmal course was 6.6 months with an average diameter of 3.25cm at the moment of management. The initial technical success rate was 100%. Twenty patients had complications in the postoperative period. Patency rates at 3, 6, 12 and 24 months were 89.5%, 81.6%, 71% and 63.1%, respectively. Factors predictive of thrombosis were diabetes (P=0.001), peripheral arterial disease (P=0.003), number of punctures per week (P=0.003) and context of emergency presentation (P=0.001).

CONCLUSION

Aneurysmorrhaphy seems to be the best conservative surgical treatment for aneurysmal complications of hemodialysis vascular access fistulae. This surgical approach allows us to conserve the native autologous vascular access and spare the patient's venous network.

Aneurysms in Vascular Access: State of the Art and Future Developments

A master class was held at the Vascular Access at Charing Cross (VA@CX2017) conference in April 2017 with invited experts and active audience participation to discuss arteriovenous (AV) vascular access aneurysms, a serious and common complication of vascular access (VA). The natural history of aneurysms in VA is poorly defined, and although classifications exist they are not uniformly applied in studies or clinical practice. True and pseudo aneurysms of AV access occur. Whilst an AV fistula by definition is an abnormal dilatation of a blood vessel, an agreed definition of 18 mm, or 3 times accepted maturation diameter, is proposed. The mechanism of aneurysmal dilatation is unknown but appears to be a combination of excessive external remodeling, wall changes due to injury, and obstruction of outflow. Diagnosis of AV aneurysms is based on physical examination and ultrasound. Venography and cross-sectional imaging may assist and be required for the investigation of outflow stenosis. Treatment of pseudo aneurysms and true aneurysms of VA (AVA) is not evidence-based, but relies on clinical experience and available facilities. In many AVA, a conservative approach with surveillance is suitable, although intervals and modalities are unclear. Avoidance of rupture is imperative and preemptive treatment should aim for access preservation, ideally with avoidance of prosthetic materials. Different techniques of aneurysmorrhaphy are described with good results in published series. Although endovascular approaches and stenting are described with good short-term results, issues with cannulation of stented areas occur and, while possible, this is not recommended, and long-term access revision is recommended.

Cardiac remodeling after reduction of high-flow arteriovenous fistulas in end-stage renal disease

In patients with end-stage renal disease, excessive blood flow through an arteriovenous fistula (AVF) may lead to volume overload-induced cardiac remodeling and heart failure. It is unclear which patients with hyperfunctional AVF may benefit from AVF reduction or ligation. The indication for the procedure is often based on AVF flow. Because cardiac remodeling is driven by increased venous return, which is equivalent to cardiac output, we hypothesized that an elevated cardiac index (CI) might better identify subjects with reverse remodeling after AVF reduction. Thirty patients (age 52±12 years, 73% male) with AVF flow ⩾1.5 l min(-1) underwent comprehensive echocardiographic evaluations before and after AVF reduction. At baseline, 16 patients had a normal CI (2.5-3.8 l min(-1) m(-2)) and 14 had a high CI (4.0-6.0 l min(-1) m(-2)). A left ventricular end-diastolic diameter decrease after operation was predicted by elevated baseline CI (P<0.01), but not elevated AVF flow (P=0.07). There was a significant decrease in CI, left ventricular mass, left atrial and right ventricular diameter and pulmonary systolic pressure in the high CI group but not in the normal CI group. After AVF reduction, systemic vascular resistance decreased in the normal CI group, whereas it did not change in the high CI group. In conclusion, reduction of high-flow AVF leads to reverse cardiac remodeling but only in patients with elevated CI. The variability of the response of systemic vascular resistance to AVF flow may explain this observation. Increased CI but not increased AVF flow may better determine candidates for AVF reduction.

Venous aneurysm complicating arteriovenous fistula access and matrix metalloproteinases

Introduction

An arteriovenous fistula (AVF) for placed for hemodialysis may be burdened by one particular complication—the formation of a venous aneurysm. It has been shown that matrix metalloproteinases (MMPs) and neutrophil gelatinase-associated lipocalin (NGAL) could represent markers of disease in both venous and arterial vessels.

Materials and methods

This case study reports a rare case of enormous venous aneurysm-correlated MMP and NGAL levels in a woman with an AVF.

Results

Significantly higher levels of plasma MMP-1, MMP-8, MMP-9, and NGAL were detected in this patient during aneurysmal evaluation before the surgery; these levels significantly decreased 1, 3 and 6 months after surgery.

Conclusion

MMP and NGAL levels could represent a marker of aneurysmal disease, and their plasma evaluation could help physicians to stratify the risk of complications in patients with an AVF.

True aneurysm in autologous hemodialysis fistulae: definitions, classification and indications for treatment

Introduction

Definition, etiology, classification and indication for treatment of the arteriovenous access (AVA) aneurysm are poorly described in medical literature. The objectives of the paper are to complete this information gap according to the extensive review of the literature.

Methods

A literature search was performed of the articles published between April 1, 1967, and March 1, 2014. The databases searched included Medline and the Cochrane Database of Systematic Reviews. The eligibility criteria in this review studies the need to assess the association of aneurysms and pseudoaneurysms with autologous AVA. Aneurysms and pseudoaneurysms involving prosthetic AVA were not included in this literature review. From a total of 327 papers, 54 non-English papers, 40 case reports and 167 papers which did not meet the eligibility criteria were removed. The remaining 66 papers were reviewed.

Results

Based on the literature the indication for the treatment of an AVA aneurysm is its clinical presentation related to the patient's discomfort, bleeding prevention and inadequate access flow. A new classification system of AVA aneurysm, which divides it into the four types, was also suggested.

Conclusions

AVA aneurysm is characterized by an enlargement of all three vessel layers with a diameter of more than 18 mm and can be presented in four types according to the presence of stenosis and/or thrombosis. The management of an AVA aneurysm depends on several factors including skin condition, clinical symptoms, ease of cannulation and access flow. The diameter of the AVA aneurysm as a solo parameter is not an indication for the treatment.

Surgical Management of Vascular access Related Aneurysms to Salvage Dialysis Access: Case Report and a Systematic Review of the Literature

Purpose

We retrospectively evaluated the surgical outcome of revising vascular access related aneurysms (VARAs) to salvage dialysis access.

Methods

Twenty-six consecutive hemodialysis patients (mean age 67.6 years, range: 32-89 years) who presented with true or false VARA and underwent surgery between January 2006 and February 2011 were enrolled in this study, and comprised 11 women and 15 men. Aneurysms were true in 21 patients and false in five; native arteriovenous fistulas (AVFs) were reported in 23, including one infected native pseudoaneurysm, and arteriovenous prosthetic grafts (AVGs) in three. The mean aneurysm diameter was 29.8 ±8.0 mm, ranging from 18 to 50 mm. Indications of surgical intervention were local pain, rapid enlargement of the aneurysm, and AVF failure due to stenosis. Surgical revision was performed by resection of VARA and concomitant creation of a new proximal arteriovenous anastomosis in 18 patients.

Results

Two aneurysms were ruptured by blunt dissection; however, bleeding did not occur due to prior clamping of the inflow artery without hemodynamic compromise. VARA plication was performed in one case in which severe calcified VARA could not be incised. No significant complications were reported, except for delayed wound healing in three patients and minor peripheral neuropathy in five. The postoperative course was uneventful without hospital mortality in all patients with VARA.

Conclusions

Aggressive surgical management of VARAs is likely to become an acceptable procedure to salvage dialysis access and consistently maintain AVF or AVG function.

Procedure for human saphenous veins ex vivo perfusion and external reinforcement

The mainstay of contemporary therapies for extensive occlusive arterial disease is venous bypass graft. However, its durability is threatened by intimal hyperplasia (IH) that eventually leads to vessel occlusion and graft failure. Mechanical forces, particularly low shear stress and high wall tension, are thought to initiate and to sustain these cellular and molecular changes, but their exact contribution remains to be unraveled. To selectively evaluate the role of pressure and shear stress on the biology of IH, an ex vivo perfusion system (EVPS) was created to perfuse segments of human saphenous veins under arterial regimen (high shear stress and high pressure). Further technical innovations allowed the simultaneous perfusion of two segments from the same vein, one reinforced with an external mesh. Veins were harvested using a no-touch technique and immediately transferred to the laboratory for assembly in the EVPS. One segment of the freshly isolated vein was not perfused (control, day 0). The two others segments were perfused for up to 7 days, one being completely sheltered with a 4 mm (diameter) external mesh. The pressure, flow velocity, and pulse rate were continuously monitored and adjusted to mimic the hemodynamic conditions prevailing in the femoral artery. Upon completion of the perfusion, veins were dismounted and used for histological and molecular analysis. Under ex vivo conditions, high pressure perfusion (arterial, mean = 100 mm Hg) is sufficient to generate IH and remodeling of human veins. These alterations are reduced in the presence of an external polyester mesh.

Autologous Surgical Reconstruction for True Venous Hemodialysis access Aneurysms–-Techniques and Results

Purpose

Due to their relatively low complication rates autogenous arteriovenous fistulas (AVFs) are the preferred access for hemodialysis. In long-standing AVF, however, aneurysmatic degeneration of the fistula vein can develop. Several treatment options have been published. We evaluated our experience with autologous surgical reconstruction in patients with AVF aneurysms in order to assess complication and patency rates.

Methods

Demographics and comorbidities of all patients operated on for true AVF aneurysms in our institution, during a 7-year period, were reviewed. Access function and surgical outcomes were evaluated with pre- and postoperative Doppler ultrasonography. Patient survival, primary and secondary access patency rates are presented.

Results

From April 2006 through March 2013, 31 patients presented with access-associated upper extremity venous aneurysms. The mean time from AVF creation to aneurysm formation was 4.9±3.6 years. The most frequent indication for surgery was aneurysm-associated stenosis (n=16) followed by high flow (n=9), complete thrombosis (n=3) and uncontrolled bleeding (n=3). All patients had autologous reconstructions: 5 resections with end-to-end anastomosis and 26 aneurysmorrhaphies. Overall patient survival at 1 and 2 years was 89% and 84%, respectively. The primary (secondary) patency rates at 6 mo, 1 and 2 years were 87%, 81% and 81% (96%, 96% and 90%), respectively.

Conclusions

Autologous surgical reconstruction is feasible in the majority of AVF aneurysms. It preserves fistula function and–-in contrast to graft interposition and endovascular repair–-keeps the advantages of an autogenous access: low complication and high patency rates.

A modified stapling technique for the repair of an aneurysmal autogenous arteriovenous fistula

OBJECTIVE

An alternative surgical technique for the repair an aneurysmatic arteriovenous fistula (AVF) using a staple remodeling operation has been developed and the results are reported.

METHODS

All patients presenting with an aneurysmatic autogenous AVF of the upper extremities between January 2012 and December 2013 were included in the analysis. The AVF was approached laterally along the entire aneurysm and then remodeled using a stapler on the lateral side of the vein wall. All stenotic segments were excised. Follow-up included a clinical visit and echo color Doppler of the fistula and was performed 7, 15, and 30 days after the intervention and every 6 months thereafter.

RESULTS

We treated 14 patients (nine men [64.3%]) with a median age of 65 years (interquartile range [IQR], 62.5-69 years). Elective interventions were performed in 12 patients (85.7%), and two underwent emergency treatment because of postcannulation bleeding. Technical success was achieved in all cases. The mean duration of the intervention was 75 minutes (IQR, 61.15-83.45 minutes). No in-hospital deaths or major morbidities were observed. Median hospitalization time was 24 hours (IQR, 25-38 hours). Postoperative puncture was performed after a median delay of 12.5 hours (IQR, 12-17 hours). No patient was lost during the follow-up, which was a median of 16.5 months (IQR, 14-23 months). Primary functional patency was 12 of 14 (85.7%). Pseudoaneurysm, bleeding, hematoma, or infection was not observed.

CONCLUSIONS

In our experience, the stapling technique proved to be easy, fast, and safe. Early follow-up outcomes showed excellent primary patency and confirmed the effectiveness of the technique because local complications were never observed.

Graftula: a composite access consisting of a graft used to repair a dysfunctional hemodialysis fistula

Nonmaturing or dysfunctional hemodialysis fistulas are often repaired with interposition grafts placed either within the fistula (fistula-to-fistula configuration), or connected to another vein (fistula-to-vein configuration). The goal of this study was to compare the survival and usefulness of the composite accesses thus created, which we call "graftulas," with upperarm grafts. This was a retrospective study wherein we determined the survival and thrombosis rates of graftulas (n=24) and upper arm grafts (n=31) placed 1/1/07 through 12/31/09 and followed through 11/30/10. Graftulas resembled grafts as most (96%) were successfully cannulated in 65 ± 43 days. Survival of graftulas was also similar to grafts (58%, 47%, and 32% vs. 56%, 47%, and 39% at 1, 2, and 3 years respectively, p=0.60). However, graftulas had a lower thrombosis rate than grafts (0.5 vs. 1.2 per patient year, p=0.04), and in the fistula-to-fistula configuration, a 2-year thrombosis-free survival of 78%. Total survival of the access site (fistula+graftula) was 92%, 73%, and 42% at 1, 3, and 5 years, respectively. Graftulas possess certain beneficial properties of fistulas and grafts that allows for continued use of the original access site.

Aneurysm of the tibial-saphenous fistula in hemodialysis patient: the results of surgical treatment

Arteriovenous fistulas are widely used for hemodialysis patients with end-stage renal failure. Due to the lack of suitable veins because of the arteriovenous fistulas previously opened in the upper extremity, alternative access routes are being tested. Few complications of long-term alternative arteriovenous fistulas have been reported in the literature. We report the results of surgical repairs of aneurysms that occurred on anterior tibial-saphenous arteriovenous fistulas (along the vein) in patients with end-stage renal disease after 5 years on hemodialysis.

Technique for a Single-Time Correction of Arteriovenous Fistula Aneurysm in Conjuction with Creation of a New Venous Drainage Pathway

Aneurysm and stenosis are among the most frequent complications of an arteriovenous fistula (AVF) for hemodialysis. The occurrence of the two kinds of problem may be found in one and the same patient, affecting the use of the AVF and even rendering its use impossible. We report the technique used for correction of a patient's aneurysmal dilations of radio-cephalic AVF and stenosis after the aneurysmal segment, with an increase in post-punction bleeding during the hemodialysis sessions. This was treated with resection and aneurysmorrhaphy associated with the preparation of a new anastomosis with the brachial vein.

Correção cirúrgica de aneurismas saculares de fístula arteriovenosa para hemodiálise utilizando a técnica de aneurismorrafia

Uma das complicações mais frequentes da fístula arteriovenosa (FAV) para hemodiálise é o desenvolvimento de um aneurisma. A formação de aneurismas geralmente decorre de um enfraquecimento da parede venosa devido às repetidas punções, e sua rotura causa hemorragia intensa que pode levar à morte. Descrevemos o caso de uma paciente com dois aneurismas saculares de FAV, tratados através de aneurismorrafia, detalhando a técnica cirúrgica utilizada e a evolução pós-operatória. A técnica de rafia simples da parede constitui uma boa alternativa no reparo da parede da FAV quando o aneurisma é de curta extensão, evitando a colocação de um material protético e a confecção de duas anastomoses.