Andrew J. Jackson

Early cannulation prosthetic graft (Acuseal) for arteriovenous access: a useful option to provide a personal vascular access solution.

Purpose Early cannulation arteriovenous grafts (ecAVGs), such as the GORE® Acuseal™, have “low bleed” properties permitting cannulation within 24 hours of insertion. They may provide an alternative to tunneled central venous catheters (and associated line complications) in patients requiring urgent vascular access. Methods We present our early experience of 37 patients treated with the GORE® Acuseal™ ecAVG. Results A total of 11 upper limb, 24 lower limb and 2 complex graft procedures were performed. Indications for ecAVG were as follows: bridge to transplantation (21.6%); bridge to arteriovenous fistula (AVF) maturation (8.1%); AVF salvage (8.1%); no native options (67.6%, including 17 patients with bilateral central vein stenosis); 36 AVGs (97.3%) were successfully cannulated. Mean time to first cannulation: 30.4±23.4 hours (range: 2–192). Primary and secondary patency rates at 3, 6 and 12 months were 64.9%, 48.6%, 32.4% and 70.2%, 59.4%, 40.5% respectively. The systemic bacteremia rate was 0.2 per 1,000 access days. There was one perioperative death. Other complications included hematoma at cannulation sites (n=9), pseudoaneurysm (n=3) and local infection at graft site (n=6). A total of 26 of 37 patients (70.6%) achieved a “personal vascular access solution”: bridge to transplantation (n=8), bridge to functioning AVF/interposition AVG (n=5), maintenance hemodialysis via ecAVG (n=13); death with functioning AVG (n=1). Conclusions Early experience with the GORE® Acuseal™ is encouraging. Patency and bacteremia rates are at least comparable to standard polytetrafluoroethylene grafts. ecAVGs have permitted cannulation within 24 hours of insertion and line avoidance in the majority of patients. Nearly three-quarters of patients achieved a definitive “personal vascular access solution” from their ecAVG.

Bilateral Central Vein Stenosis: Options for Dialysis Access and Renal Replacement Therapy when all upper Extremity Access Possibilities have been Lost:

Purpose Patients with bilateral central vein stenosis present a unique challenge: treatment options are limited, largely unproven and associated with reputedly poor outcomes. Our aim was to compare patency rates of different access and renal replacement treatment (RRT) modalities in patients with bilateral central vein stenosis/occlusion. Material and methods Data on all patients presenting to a tertiary referral vascular access centre with end-stage vascular access (defined by bilateral central vein stenosis/occlusion with loss of upper limb access) over a 5-year period were included. 3, 6 and 12-month patencies of translumbar catheters (TLs), tunnelled femoral catheters (Fem), native long saphenous vein loops (SV), prosthetic mid-thigh loop grafts (ThGr), peritoneal dialysis (PD), and expedited donation after cardiac death (DCD) cadaveric renal transplants (Tx) via local allocation policies were compared using log-rank test. Kaplan–Meier survival analysis was used to estimate long-term access survival. Results One hundred forty-six vascular access modalities were attempted in 62 patients (62 Fem, 25 TL, 15 SV, 25 ThGr, 8 PD, 11 Tx). Median follow-up was 876±57 days. Three, 6 and 12-month primary-assisted patencies for each modality were as follows: Fem: 75.4%, 60% and 28%; TL: 88%, 65% and 50%; SV: 87.5%, 60% and 44.6%; ThGr: 64%, 38% and 23.5%; PD: 62.5%, 62.5% and 50%; Tx: 72.7%, 72.7% and 72.7%. SV had better secondary patency at 900 days (76.9%) than ThGr (49.2%) or Fem (35.8%) (p<0.01). No patients died as a result of loss of access. Conclusion Patients with bilateral central vein stenosis often require more than one vascular access modality to achieve a “personal access solution.” Native long saphenous vein loops provided the best long-term patency. Expedited renal transplantation with priority local allocation of DCD organs to patients with precarious vascular access provides a potential solution to this difficult problem.

Pharmacotherapy to improve outcomes in vascular access surgery: a review of current treatment strategies

BACKGROUND Renal failure is a major cause of morbidity in western Europe, with rising prevalence. Vascular access complications are the leading cause of morbidity among patients on haemodialysis. Considering the health care burden of vascular access failure, there is limited research dedicated to the topic. METHODS Randomised control trials of medications aimed at improving vascular access patency were identified using a medline search between January 1950 and January 2011. RESULTS Thirteen randomised trials were identified, investigating antiplatelets, anticoagulants and fish oil in preserving vascular access patency. Outcomes are presented and reviewed in conjunction with the underlying pathophysiological mechanisms of failure of vascular access. DISCUSSION Vascular access failure is a complex process. Most clinical trials so far have involved medications primarily aimed at preventing thrombosis. Other contributing pathways such as neointimal hyperplasia have not been investigated clinically. Improved outcomes may be seen by linking future therapies to these pathways.

Cephalic arch stenosis: angioplasty to preserve a brachiocephalic fistula or new brachiobasilic fistula?: a cost-effectiveness study

Abstract Background: Our aim was to evaluate the cost-effectiveness of repeat angioplasty versus new brachiobasilic fistula (BBF) in patients with symptomatic cephalic arch stenosis (CAS). Methods: Patients presenting with symptomatic CAS (n = 22) underwent angioplasty. They were compared to patients undergoing BBF creation (n = 51). Primary outcomes were functional primary arteriovenous fistulae patency at 3, 6 and 12 months. Data were collected on number of interventions, alternative accesses and hospital days for access-related complications. Quality of life was assessed using Kidney Disease Quality of Life-36 scores. Decision tree, Monte Carlo simulation and sensitivity analysis permitted cost-utility analysis. Healthcare costs were derived from Department of Health figures and are presented as cost (£)/patient/year, cost/access preserved and cost/quality of life-adjusted year (QALY) for each of the treatment strategies. Results: Functional primary patency rates at 3, 6, 12 months were 87.5%, 81% and 43% for repeated angioplasty and 78%, 63% and 41% for BBF. The angioplasty cohort required 1.64 ± 0.23 angioplasties/patient and 0.64 ± 0.34 lines/patient. BBF required 0.36 ± 0.12 angioplasties/patient and 1.2 ± 0.2 lines/patient. Patients in the BBF cohort spent an additional 0.9 days/year in hospital due to access-related complications. Mean cost/patient/year in the angioplasty group was £5247.72/patient/year versus £3807.55/patient/year in the BBF cohort. Mean cost per access saved was £11,544.98 (angioplasty) versus £4979.10 (BBF). Average cost per QALY was £13,809.79 (angioplasty) versus £10,878.72 per QALY (BBF). Conclusions: CAS poses a difficult management problem with poor outcomes from conventional angioplasty. Optimal management will depend on patient factors, local outcomes and expertise, but consideration should be given to creation of a new BBF as a cost-effective means to manage this difficult problem.

Pharmacotherapy to improve outcomes in infrainguinal bypass graft surgery: a review of current treatment strategies.

A total of 12,000 infrainguinal bypass grafts are performed annually in the United Kingdom, with outcomes suboptimal: 20% of above-knee vein grafts require intervention by 3 years. Transatlantic Inter-Society Consensus (TASC) guidelines exist on pharmacological management of peripheral vascular disease patients, however, little is recommended regarding optimum pharmacological management following revascularization to improve graft patency. The current recommendation is that all patients are on an antiplatelet agent following bypass grafting, the only intervention with significant evidence supporting use. This article will review pharmacological strategies aimed at improving the survival of infrainguinal vein grafts and the current evidence base for their use.

Improving arteriovenous fistula patency: Transdermal delivery of diclofenac reduces cannulation-dependent neointimal hyperplasia via AMPK activation

Creation of an autologous arteriovenous fistula (AVF) for vascular access in haemodialysis is the modality of choice. However neointimal hyperplasia and loss of the luminal compartment result in AVF patency rates of ~ 60% at 12 months. The exact cause of neointimal hyperplasia in the AVF is poorly understood. Vascular trauma has long been associated with hyperplasia. With this in mind in our rabbit model of AVF we simulated cannulation autologous to that undertaken in vascular access procedures and observed significant neointimal hyperplasia as a direct consequence of cannulation. The neointimal hyperplasia was completely inhibited by topical transdermal delivery of the non-steroidal anti-inflammatory (NSAID) diclofenac. In addition to the well documented anti-inflammatory properties we have identified novel anti-proliferative mechanisms demonstrating diclofenac increases AMPK-dependent signalling and reduced expression of the cell cycle protein cyclin D1. In summary prophylactic transdermal delivery of diclofenac to the sight of AVF cannulation prevents adverse neointimal hyperplasic remodelling and potentially offers a novel treatment option that may help prolong AVF patency and flow rates.

Venous Outflow Stenosis of the Brachiocephalic Fistula: A Single Entity, oris the Cephalic Arch Different?

Background: Cephalic Arch Stenosis (CAS) is emerging as an important cause of Brachiocephalic Fistula (BCF) failure. The optimal management strategy for dysfunctional AVF as a result of CAS is yet to be defined. Endovascular management is generally employed as first line treatment based upon success in other venous stenosis sites. We compare the outcomes of angioplasty in CAS to other venous stenoses causing BCF dysfunction. Methods: 62 patients with dysfunctional BCF due to venous segment pathology were identified and proceeded to angioplasty. Lesions were categorized anatomically: 19 CAS, 22 venous outflow, 21 swing segment(<3cm of anastomosis). Anastomotic stenoses were excluded. Endovascular intervention was carried out in a standard fashion; 8-10mm balloon angioplasty at the interventionalist’s discretion. Patients were followed prospectively by regular clinical and venous pressure monitoring of the fistula. Re-intervention was performed on clinical suspicion of recurrence. Results: Mean duration of follow-up was 402 days. Patient demographics were comparable across the three groups except a lower incidence of diabetes in the cephalic arch cohort (15.7% vs. 28.2% vs. 25.0%). Swelling and aneurysmal fistulae were more common presenting complaints in CAS (15.7% vs. 2.6% vs. 0%). Mean length of cephalic arch stenosis was shorter(1.6cm vs.3.1cm vs.2.5cm). Primary patency of cephalic arch angioplasty was 68.8%, 43.7% and 31.0% at 3, 6 and 12 months respectively. Primary assisted patency was 87.5%, 81.0% and 43.0%. There was no significant difference in primary or primary assisted patency compared to other outflow stenoses. 2.3 interventions/ patient were required to preserve the access in the CAS cohort vs. 1.1 interventions/ patient for venous outflow stenosis and 1.3 interventions/ patient for swing segment stenoses. Conclusion: CAS bears a different clinical presentation to other venous outflow stenoses. Despite being shorter, and apparently a more attractive target lesion, the hallmark is a requirement for repeated endovascular intervention when compared to other venous stenoses causing BCF dysfunction