This is an exciting time for vascular access. Minimally invasive anastomosis devices have been developed and are being utilised in the creation of percutaneous arteriovenous fistulae (pAVF) in the upper extremity, writes Jeffrey Hull, Richmond, USA.
The vision for haemodialysis access is to evaluate end-stage renal disease patients in the office with clinical exam and Doppler ultrasound mapping. In appropriate patients, we can now create a percutaneous arteriovenous fistula in the office-based lab with the Ellipsys vascular access system (Avenu Medical). Fistula follow-up, maturation and maintenance are also done at the office-based lab establishing a valuable continuity of care.
This approach was successfully applied in the pivotal US clinical trial where 117 patients were enrolled at five sites across the USA. All the procedures were done in the office-based lab, using ultrasound guidance. The results of this study, designed to demonstrate the safety and efficacy for the percutaneous creation of arteriovenous fistulae, will be forthcoming in the next few months. Avenu Medical has received CE mark approval for the commercial sale of Ellipsys vascular access system in Europe.
The current anastomosis device takes advantage of the unique anatomy in the ante-cubital fossa. An anastomosis is created between in-situ arteries and veins that are side by side. The Ellipsys catheter creates an anastomosis between the proximal radial artery and the perforating vein. The resultant fistulae are multi-vein outflow with filling of the cephalic and basilic veins in the upper arm. The central advancement of the Ellipsys anastomosis device is the development of an image-guided, catheter-based procedure that creates an anastomosis without an implant or foreign body.
The exciting part for practicing interventionists adopting one of the anastomosis device technologies will be to develop methods of practice that suit the needs of their patients and facilities. Academic practices will have the opportunity to thoroughly test the anastomosis devices, and develop the best practices and evidence based recommendations for their use. Appropriate methods of practice need to be developed for patient selection, imaging guidance, procedure venue, anatomic location of anastomosis, anatomic location for dialysis cannulation, and fistula maintenance. The cycle of innovation to practice invigorates our specialty.
It is been 50 years since Brescia-Cimino described the first modern arteriovenous fistula using the surgical technique. While there have been numerous advancements in surgical fistulae, the basic principles have remained the same. A vein is identified as suitable for fistula creation, the vein is dissected free and then attached to an adjacent artery with a sutured anastomosis. Typically the attached vein is a single vessel matured for dialysis. This has been the safest and most cost-effective method of providing haemodialysis. Despite being the best current access for haemodialysis there are problems providing patients with a functional fistula. From 30–60% of fistulae created fail to mature into functioning fistulae, leaving patients on catheter dialysis. The reasons for non-maturity are varied and include early thrombosis, intimal hyperplasia and inadequate vein development. The pAVF may help overcome the problems with surgical fistulae. The pAVF is more easily monitored and more amenable to treatment in the early postoperative period due to lack of incisions and tenderness. The pAVF is not limited to a single pre-selected outflow vein.
A related problem in dialysis access is that 80% of patients initiate dialysis with a catheter, a percentage that has not changed over the last 10 years. This is due to lack of patient education, lack of payment, and resistance to surgical procedures. The minimally invasive percutaneous arteriovenous fistula will allow a larger number of physicians to create high quality fistulae.
The committed interventionalist can join a multidisciplinary group of committed vascular access surgeons and nephrologists in the care of end-stage renal disease patients. Increased manpower with minimally invasive and cost-effective options for creating fistulae will help interventional radiologists, surgeons, nephrologists, patients, and underwriters of healthcare become more proactive in using fistulae for haemodialysis, ultimately, reducing the morbidity, mortality and cost of catheter dialysis.
Jeffrey E Hull is director of the Richmond Vascular Center in Richmond, USA. He is a founder, stockholder and consultant to Avenu Medical