Based on over four years of experience in a single centre, Robert Shahverdyan (Asklepios Klinik Barmbek, Hamburg, Germany) claims that endovascular arteriovenous fistula (endoAVF) creation “keeps future options open,” but is not a replacement for surgical fistula creation.
Speaking at the Leipzig Interventional Course (LINC) 2022 (6–9 June, Leipzig, Germany), Shahverdyan reported new outcomes from his long-term experience with the Ellipsys (Medtronic) and WavelinQ (BD) endoAVF systems, as well as with surgical fistula creation.
The presenter stressed that current studies of end-stage renal disease show an ageing patient population with an increasing number of comorbidities. Additionally, these studies highlight lengthening waiting times for a transplant, surpassing 10 years in many cases. “As vascular access creators,” he said, “we are confronted with longer dialysis needs, and with longer access needs”.
Among over 500 patients who were screened at the Asklepios Klinik Barmbek’s Vascular Access Center over the last four years, Shahverdyan noted that 46% were eligible for a radiocephalic surgical fistula, and that 80% had a suitable perforating vein for a surgical Gracz fistula. The presenter noted that suitability for the endoAVF systems he uses—Ellipsys and WavelinQ—depends on a patient’s anatomy. In the Hamburg experience, he said, around 61% of patients had suitable anatomy for at least one type of endoAVF creation, and 23 % had suitable anatomy for both endoAVF systems.
Over the last four years, Shahverdyan noted that he has used the VasQ device (Laminate Medical) as standard of care in radiocephalic AVFs. Out of over 750 creations included in the Hamburg data, 92% are AVF creations, with 86% of all access creations having a forearm anastomosis. There were around 200 endoAVFs, 126 Gracz-type AVFs, 63 AV grafts, and the rest were radiocephalic fistulas, a group which also included 80 snuffbox fistulas.
The technical success for both surgical and endoAVF creation was “really high,” he informed the LINC audience. In terms of physiological maturation for those fistulas that were over four weeks old since creation, Shahverdyan reported a rate of over 90% for VasQ radiocephalic fistulas and almost 90% for Ellipsys and Gracz fistulas, with snuffbox and WavelinQ “a little bit behind” with roughly 80% maturation rates. Regarding clinical maturation, which was assessed in patients whose fistulas were subsequently used for dialysis, the presenter reported a cannulation success rate of over 90% for the Ellipsys and radiocephalic AVFs.
High flow and steal are also important factors to consider, said Shahverdyan, due to the fact that the fistulas in question are being created for long-term use. He reported seeing “practically no steal” in distal fistulas, just one case of steal with the Ellipsys, and high rates of surgical steal and high flow for Gracz fistulas, particularly if they had a brachial artery-based anastomosis.
In terms of assisted and secondary patency rates, the Ellipsys, radiocephalic, and Gracz fistulas had over 80% patency rates in the four-year Hamburg experience. In Shahverdyan’s opinion, primary patency rates “are not important,” except in cases with frequent reinterventions.
Comparing proximal forearm AVFs, and remarking here on procedure time, the presenter detailed that this was “significantly shorter” for Ellipsys, and that time to cannulation for Ellipsys and Gracz were the shortest. The number of interventions per patient was “slightly higher” for Ellipsys, however this system resulted in the fewest abandoned fistulas, closely followed by Gracz.
In his conclusion, Shahverdyan stressed that “we need to consider some learning curves” for both endoAVFs, but also surgical fistulas, to address issues like kinking and torsion. He summarised that there are “some differences” between the Ellipsys, WavelinQ, and surgical fistulas, but stressed that endoAVF has an “extremely low” rate of perioperative complications. He reiterated that endoAVFs enable future intervention, but should be seen as a complement to the vascular access surgeon’s armamentarium, instead of a complete solution.