CHICAGO – Endovascular repair of popliteal artery aneurysms is a relatively safe and viable off-label alternative to open repair, but appropriate anatomy is essential. This includes a landing zone of at least 2 cm above and below the aneurysm, minimal discrepancy in size between the proximal and distal landing zones, and lack of extensive vessel tortuosity due to potential kinking of the endograft, Dr. Neal S. Cayne said at a symposium on vascular surgery sponsored by Northwestern University.
The risk of kinking and graft thrombosis also excludes patients who frequently flex their knee more than 90 degrees, such as carpenters and gardeners.
Patients with a contraindication to antiplatelet medication are also off limits, as clopidogrel (Plavix) has been shown to be a predictor of success, said Dr. Cayne, director of endovascular surgery at New York University Langone Medical Center.
In 2012, his team reported technical success in 25 of 26 endovascular popliteal artery aneurysm (PAA) repairs performed in 21 consecutive patients between January 2004 and January 2011, with the one technical failure due to stent graft infolding (J. Vasc. Surg. 2012;55:1647-53).
Primary and secondary patency rates were both 91.2% at 1 year, and were 85.5% and 91.2%, respectively, at 2 years. All patients were maintained on aspirin or clopidogrel.
No limb loss was reported, but three occlusions occurred during follow-up at 4, 14, and 26 months. One patient required a tibial artery bypass for a nonhealing wound, and two were successfully repaired with open thrombectomy. All three occlusion patients had single-vessel runoff.
Based on our data, in general, I will not stent someone "with single-vessel outflow, and I also will not stent someone who, for some reason, can’t take antiplatelet agents," Dr. Cayne said.
Even when patients present urgently and the PAA has thrombosed, endovascular repair is not an option if there is only one outflow vessel. "I would do a bypass; there’s nothing wrong with open surgery," he said.
A recent unpublished review of 79 PAAs treated at Langone from 1998 to 2012 with both approaches found 5-year primary patencies of 67% for open repair and 80% for endovascular repair (P less than .05). Secondary patency was 90% in both groups.
One amputation occurred in the open group, but occlusion rates were higher using endovascular repair with one-vessel runoff (P = .003), Dr. Cayne said.
As expected, length of stay was shorter with endovascular repair (1.9 vs. 6.4 days; P less than .001).
Follow-up was longer for the 36 open PAAs than the 43 endovascular PAAs (75 vs. 34 months), but patients in both groups were similar with respect to age, comorbidities, PAA size, runoff, and symptoms, he said.
During a discussion following the presentation, some attendees said they still prefer to use bypass for all patients with PAA, and asked how candidates are selected for stent placement.
"Number one and most important is the anatomy," Dr. Cayne said. "The one advantage of endovascular repair is that if you have a patient too sick to get general or even regional anesthesia, you can do it under local [anesthesia] almost all the time with a small cutdown or puncture. But you do have that long discussion with the patient that this is a non–FDA-approved, off-label use. We provide them with the data, but some patients in New York will come in with pages and pages of literature and say, ‘Nope, I want a stent, I want this particular stent, and this is the way I want you to do it.’ "
The stent of choice at Langone has been Gore’s Viabahn covered stent graft, which is FDA approved for treating occlusive disease rather than PAA. The device is usually oversized by 10%-15%, but no more than that, because of the risk of graft infolding, Dr. Cayne said.
If more than one graft is needed, a maximum of no more than 1-mm size differential between grafts is suggested. A minimum overlap of 2-3 cm between grafts is also preferred.
Last year, surgeons reported a dismal 50% occlusion rate within just 6 weeks in the endovascular treatment of six PAAs using a novel, multilayer stent (Cardiatis’s Multilayer Aneurysm Repair System) (J. Endovasc. Ther. 2013;20:381-8), he observed.
Dr. Cayne reported receiving honoraria as a consultant from Cook Medical.