A new study carried out on both patients and rats shows that artery-to-vein configuration of arteriovenous fistulae (AVF) improves hemodynamics and decreases hyperplasia in the case of the latter, and leads to longer-term patency with reduced reintervention rates in patients.
The findings—made by Hualong Bai, MD, Alan Dardik, MD, and colleagues at the vascular biology and therapeutics program and the department of surgery at Yale School of Medicine, Connecticut—were published as the cover research article in the latest issue of Science Translational Medicine.
The research team hailed their findings as supporting the use of artery-to-vein-configured AVFs for durable hemodialysis access.
Introducing the matter under investigation, they point out that some 60% of conventional AVF, or vein-to-artery, fail to mature, with just 50% remaining patent at one year.
Previously, the researchers had shown improved maturation and patency in a 53-patient pilot study of the radial artery deviation and reimplantation (RADAR) technique that uses an artery-to-vein configuration.
The new study involved a single institution cohort study on the patient side, with a retrospective review of a prospectively maintained clinical database. Furthermore, a bilateral carotid artery-internal jugular vein AVF model was developed to assess both artery-to-vein and vein-to-artery configurations in a single rat.
In the human portion of the study, 201 patients who had RADAR performed between October 2014 and April 2017 were compared with 73 patients who received control (vein-to-artery) AVF between May 2013 and September 2014. In a pooled cohort that included both female and male patients, AVF performed with RADAR had significantly higher rates of maturation at six weeks (p=0.002) and three months (p=0.001) compared to control AVF, with more RADAR remaining in use for hemodialysis at the end of follow-up (p<0.0001), the investigators revealed.
The cumulative reintervention rate in the juxta-anastomotic segment was significantly lower in patients with RADAR compared to controls (cumulative reintervention rate: 12.6% vs. 42.6% at 12 months and 17.3% vs. 49.1% at 36 months, p<0.000001). Both primary and secondary patencies were significantly increased at 12 and 36 months in patients treated with RADAR compared to controls (primary patency: 72.2% vs. 48.1% at 12 months and 62.1% vs. 37.6% at 36 months, p=0.000065; secondary patency: 98.4% vs. 72.1% at 12 months and 94.9% vs. 66.8% at 36 months, p<0.0000001).
Patients with RADAR required significantly fewer reinterventions (30.1 per 100 person-years versus 39.9 per 100 person-years, p=0.03). The incidence of reintervention for venous juxta-anastomotic stenosis was 1.6 per 100 person-years with RADAR compared to 17.1 per 100 person-years (p< 0.0001), whereas the RADAR group required more arterial reinterventions (p= 0.02).
“These long-term clinical results confirm the results of our pilot study and demonstrate that RADAR is associated with less juxta-anastomotic stenosis and improved rates of maturation and long-term patency in human patients,” the authors write.
In addition, comparisons were studied in the rat model.
“There was decreased cell proliferation and neointimal hyperplasia in the A-V configuration in male and female animals, but no difference in hypoxia between the artery-to-vein and vein-to-artery configurations. Similar trends were seen in uremic male rats,” the researchers described. “Computed tomography and ultrasound-informed computational modeling showed different hemodynamics in the artery-to-vein and vein-to-artery configurations, and improving the hemodynamics in the vein-to-artery configuration was protective against neointimal hyperplasia.”
The authors added: “These findings collectively demonstrate that RADAR is a durable surgical option for patients requiring radial-cephalic AVF for hemodialysis access.”