Arteriovenous fistula aneurysms in patients with Alport's

Hybrid Revision of Dysfunctional Aneurysmal Arteriovenous Fistulas

Endovascular therapy has become the first-line treatment for failing hemodialysis arteriovenous fistulas (AVFs). However, open revision remains an important modality for vascular access maintenance and the recommended approach for AVF aneurysms. This case series describes a hybrid approach for aneurysmal access revision. Three patients were referred for second opinion after failure of endovascular therapy to establish a functioning access. The medical history is briefly described to highlight the limitations of endovascular therapy and the technical advantages of the hybrid approach in these clinical scenarios.

Guidelines on vascular access for hemodialysis from the Brazilian Society of Angiology and Vascular Surgery

Chronic kidney disease is a worldwide public health problem, and end-stage renal disease requires dialysis. Most patients requiring renal replacement therapy have to undergo hemodialysis. Therefore, vascular access is extremely important for the dialysis population, directly affecting the quality of life and the morbidity and mortality of this patient population. Since making, managing and salvaging of vascular accesses falls within the purview of the vascular surgeon, developing guideline to help specialists better manage vascular accesses for hemodialysis if of great importance. Thus, the objective of this guideline is to present a set of recommendations to guide decisions involved in the referral, evaluation, choice, surveillance and management of complications of vascular accesses for hemodialysis.

Building a Scaffold for Arteriovenous Fistula Maturation: Unravelling the Role of the Extracellular Matrix

Vascular access is the lifeline for patients receiving haemodialysis as kidney replacement therapy. As a surgically created arteriovenous fistula (AVF) provides a high-flow conduit suitable for cannulation, it remains the vascular access of choice. In order to use an AVF successfully, the luminal diameter and the vessel wall of the venous outflow tract have to increase. This process is referred to as AVF maturation. AVF non-maturation is an important limitation of AVFs that contributes to their poor primary patency rates. To date, there is no clear overview of the overall role of the extracellular matrix (ECM) in AVF maturation. The ECM is essential for vascular functioning, as it provides structural and mechanical strength and communicates with vascular cells to regulate their differentiation and proliferation. Thus, the ECM is involved in multiple processes that regulate AVF maturation, and it is essential to study its anatomy and vascular response to AVF surgery to define therapeutic targets to improve AVF maturation. In this review, we discuss the composition of both the arterial and venous ECM and its incorporation in the three vessel layers: the tunica intima, media, and adventitia. Furthermore, we examine the effect of chronic kidney failure on the vasculature, the timing of ECM remodelling post-AVF surgery, and current ECM interventions to improve AVF maturation. Lastly, the suitability of ECM interventions as a therapeutic target for AVF maturation will be discussed.

A Hyperdynamic Arteriovenous Fistula Aneurysm After Long Time Renal Transplantation

CONCLUSION

Closure of arteriovenous fistula should be considered in patients who underwent successful renal transplantation to avoid potential complications that may result from the presence of unused fistula especially, in patients who are predisposed to aneurysm formation in the future.

Proximal Arteriovenous Fistulas in Hemodialysis Patients: Advantages and Disadvantages

Introduction: The main objective of the present study is to investigate the advantages and disadvantages of proximal arteriovenous native fistulas. Hemodialysis is indispensable for patients with end-stage renal disease. For this purpose, arteriovenous fistulas (AVFs) are used. Among the native fistulas, distal radiocephalic AVF is the most preferred. However, brachiocephalic AVF (BCAVF) and brachiobasilic AVF with basilic vein transposition (basilic vein transposition arteriovenous fistula [BVTAVF]) can be used for a long time in dialysis patients whose distal vascular bed is depleted.

Methods: This is a retrospective study of 117 AVFs (BCAVF and BVTAVF), in patients with end-stage chronic renal disease, that were opened with a surgical technique (2012-2018). The postoperative two-year patency rates, AVF locations, complications, and the advantages and disadvantages of these fistulas are reviewed and recorded in the light of the literature.

Results: The mean age of the patients (52 men and 65 women) was 60.6 ± 13.6 years. The percentages of primary patency rates at 3, 6, 9, 12, and 24 months were 96.6%, 93.1%, 92%, 87.4%, and 82.8% in BCAVF patients, and 96.7%, 93.3%, 90%, 86.7%, and 80% in BVTAVF patients, respectively. The percentages of secondary patency rates at 6, 12, and 24 months were 100%, 93.3%, and 86.7% in BCAVF patients, and 100%, 100% and 87.7% in BVTAVF patients, respectively. Fistula thrombosis was seen as the most common complication. The early complication was bleeding/hematoma. As late complications, we encountered steal syndrome, ischemic pain in the relevant extremity, pseudoaneurysm, and high-output heart failure.

Conclusion: Proximal AVFs are preferable fistulas with early maturation and high primary patency rates. We believe that relatively high complications can be avoided by opening fistulas with an appropriate surgical technique.

Partial aneurysmectomy for treatment of autologous hemodialysis fistula aneurysm is safe and effective

OBJECTIVE

The purpose of this study was to evaluate the outcome and the factors associated with stenosis after treatment using partial aneurysmectomy for aneurysm in autologous arteriovenous fistulas.

METHODS

This retrospective cohort study was conducted from July 2007 to June 2016 and included patients with complicated aneurysms in upper extremity autologous arteriovenous fistulas were treated by partial aneurysmectomy. Vascular ultrasound examination was performed every 6 months after the surgery.

RESULTS

Forty-one patients (median age, 37 years; 70.7% males) were included. Of the patients, 95.1% had a radial-cephalic fistula in the forearm and nearly 88% had 1 or 2 aneurysms in arteriovenous fistulas that had been created for 10 to 84 months. Technical success of partial aneurysmectomy was achieved in all patients. The access diameter (44.0 ± 5.1 mm vs 10.4 ± 1.8 mm; P < .01) and brachial artery blood flow (1618.2 ± 277.0 mL/min vs 772.1 ± 127.4 mL/min; P < .01) were significantly decreased after the surgery. The median follow-up time was 27 months (range, 12-43 months). The primary patency rates at 6 and 12 months were 100% and 95%, respectively. Loss of patency was due to stenosis of the remodeled fistulas, which occurred in seven patients (17%). Multivariate COX regression analysis revealed that diabetes (hazard ratio, 114.28; 95% confidence interval, 2.85-4583.94; P = .01) was a risk factor for the impaired primary patency rates. A larger postprocedure residual diameter trended to favor fistula patency (hazard ratio, 0.46; P = .07). Stenosis was successfully treated with percutaneous transluminal angioplasty.

CONCLUSIONS

Partial aneurysmectomy is an effective and safe method for treating aneurysm of upper extremity autologous arteriovenous fistulas, leading to good 12-month primary patency and no aneurysm recurrence. Using a larger catheter to size the revised fistula during aneurysmectomy may increase access patency.

Alport's syndrome and intracranial aneurysm: mere coincidence or undiscovered causal relationship

A 44-year-old Caucasian man with a history of deceased donor renal transplant for end-stage renal disease from Alport’s syndrome (AS), presented with a spontaneous subarachnoid haemorrhage and hydrocephalus. Following an external ventricular drain for the hydrocephalus, a CT angiography revealed a dissection of the left vertebral artery extending into vertebro-basilar junction necessitating a bypass between left occipital artery to left posterior inferior cerebellar artery. He had a posterior fossa Craniectomy, C1 laminectomy and coiling off, of the left vertebral artery. Postprocedure course was prolonged but uneventful with complete recovery and normal renal function 18 months postpresentation. AS, a disease caused by abnormalities in the synthesis of type IV collagen, can cause aneurysms with severe and permanent neurological sequalae. We present a case of AS with intracranial arterial dissection with potential life-threatening consequences and discuss the genetic and molecular basis of AS along with review of the relevant literature.

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.

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.

Aneurysms and pseudoaneurysms in dialysis access

Aneurysms are a common and often difficult complication seen with arteriovenous vascular access for haemodialysis. The purpose of this narrative review is to define and describe the scale of the problem and suggested therapeutic strategies. A narrative review of the published literature illustrated by individual cases is presented with the aim of summarising the relevant literature. The definitions of aneurysm are inconsistent throughout the literature and therefore systematic review is impossible. They vary from qualitative descriptions to quantitative definitions using absolute size, relative size and also size plus characteristics. The incidence and aetiology are also ill defined but separation into true aneurysms and false, or pseudoaneurysms may be helpful in planning treatment, which may be conservative, surgical or radiological. The lack of useful definitions and classification along with the multitude of management strategies proposed make firm evidence based conclusions difficult to draw. Further robust well designed studies are required to define best practice for this common problem.