A small AV fistula of 3.5-4 mm has been required in about half of procedures after continuous wave Doppler failed to identify robust venous velocity signals. The goal of the AV fistula is to increase velocity but not venous pressure, and it has typically been constructed with a wrap around the greater saphenous vein to ensure that it will not enlarge over time, Dr. Comerota said.
"I’ve never been sorry I did an AV fistula. I certainly have been sorry that I have not, so now it’s a routine part of the procedure," he added.
If an iliac venous stenosis or occlusion needs to be stented, Dr. Comerota said that he prefers Wallstents.
"I’m not sure if radial strength is the best term, but Wallstents have the best compression to pressure," he explained. "We’ve used Nitinol [stents] earlier on in our experience, but we had to go back in and reline 50% to 60% of them because they just didn’t hold up the vein properly."
Initially, the team also attempted to keep the stents above the inguinal ligament, but it now takes the approach that the iliac venous occlusion can be stented into the endovenectomized portion of the external iliac vein or CFV, with the caveat that the distal end of the stent must stay above the saphenofemoral junction to preserve profunda femoris venous drainage. Stenting avoids skip lesions that might lead to recurrent thrombosis or continued functional compromise, Dr. Comerota noted.
During a discussion of the procedure, he said that symptomatic presentation and degree of disability are used to determine whether patients should undergo the rigorous procedure.
Surgeons at the Mayo Clinic reported far less promising results in 12 patients who underwent CFV endovenectomy, patch angioplasty, and stenting for chronic iliofemoral venous obstruction, with a 30% 2-year patency and 50% of ulcers with patent grafts recurring (J. Vasc. Surg. 2011;53:383-93).