Percutaneous arteriovenous fistulae creation may allow greater patient access to fistula formation as more physicians will be able to create these channels, thus potentially reducing waiting times for surgery, writes Gerard Goh, Melbourne, Australia.
The creation and maintenance of dialysis access is a large healthcare issue that challenges physicians worldwide. Dialysis is usually delivered via peritoneal dialysis catheters, percutaneous dialysis catheters or surgically created arteriovenous fistulae.
The advantages of surgically created arteriovenous fistulae over alternative dialysis access is well established. Studies have shown that surgically created arteriovenous fistulae have lower rates of three-year mortality for patients than if they receive an arteriovenous graft or central venous catheter for haemodialysis.1 Furthermore, surgical fistulae have also been shown to have lower infection rates, re-operation rates and be economically less expensive per year.2 However surgical fistulae often require multiple interventions to maintain functionality. Central venous catheters have been associated with central venous stenosis, possibly due to superior vena cava barotrauma and/or local irritation and inflammation of the venous wall. Should a central venous stenosis develop this may lead to further complications, such as occlusion, necessitating further interventions and possibly impacting on future upper limb dialysis access options.
A novel alternative method to create arteriovenous fistulae is by percutaneous endovascular means. Two companies that have developed percutaneous devices to create arteriovenous fistulae are TVA medical with the EverlinQ system and Avenu Medical with the Ellipsys system.
The EverlinQ device is a dual catheter device that received CE marking in 2014. Retrograde access into the brachial artery and brachial vein is achieved under ultrasound guidance with a micropuncture kit. Wires are placed and 6 and 7F vascular sheaths are placed in the artery and veins respectively. 0.018” wires are manipulated into the interosseous artery and vein and the EverlinQ catheters are inserted. The catheters have rare earth magnets so that once they are aligned appropriately, these catheters are activated holding the artery and vein together. A small radiofrequency electrode is deployed and activated creating a fistula between the artery and vein. The catheters are then removed and the brachial vein is embolized with a coil to redirect venous blood into the superficial systems. The as-yet unpublished NEAT trial, incorporating centres from Canada and Australia, recently preliminarily reported a primary technical success of creating an arteriovenous fistula of 98.3% (59/60 patients) and at three months 91.3% (57/60 patients) had a physiologically usable fistula (defined as a brachial artery flow rate ≥500ml/min and a cephalic/basilic/medican cubital vein diameter of ≥4mm or a successful dialysis with two needles).
The Ellipsys system is a single catheter electrocautery device. A retrograde puncture and access of the median cubital vein is performed and over the wire, a needle is used to enter the perforating vein. The needle is then directed towards and advanced to puncture the adjacent radial artery under ultrasound guidance. A 6F sheath is inserted. The Ellipsys device is then introduced and the sheath retracted back, positioning the distal tip of the electrocautery device within the radial artery and the proximal tip in the perforating vein. The device is engaged closing the electrocautery tips which hold the artery and vein together. The device is activated and an electrocautery is performed creating the fistula (see article below).
Percutaneous arteriovenous fistulae creation may allow greater patient access to fistula formation as more physicians will be able to create arteriovenous fistulae, thus potentially reducing waiting times for surgery. Early research seems to indicate that there may be a quicker maturation time of arteriovenous fistulae over surgically created ones; however longer term research with larger patient numbers is needed. This should be an interesting space to watch.
Gerard S Goh is an interventional radiologist at The Alfred Hospital, Melbourne, Australia. He has reported no disclosures pertaining to this article
References
- Perl J et al. Hemodialysis vascular access modified the association between dialysis mortality and survival. J Am Soc Nephrol. 2011 Jun; 22(6):1113–1121
- Woo K et al. Influence of vascular access type on sex and ethnicity-related mortality in hemodialysis-dependent patients. Perm J. 2012 Spring; 16(2):4–9
