Point/Counterpoint

Point/Counterpoint: Is endograft PAA repair durable?


 

AT MIDWESTERN VASCULAR 2016

 

Endovascular repair is durable

Endovascular repair of popliteal artery aneurysms is vastly superior to all other previous techniques of popliteal aneurysm repair. Half of all popliteal artery aneurysms are bilateral, and 40% are associated with abdominal aortic aneurysm; 1%-2% of patients with abdominal aortic aneurysm have a popliteal aneurysm (ANZ J Surg. 2006 Oct;76[10]:912-5). Less than 0.01% of hospitalized patients have popliteal artery aneurysms, and men are 20 times more prone to them than women are.

Traditional treatment involves either bypass with interval ligation or a direct posterior approach with an interposition graft, but surgery is not without its problems. I think of the retired anesthesiologist who came to me with a popliteal artery aneurysm (PAA) that his primary care doctor diagnosed. “I’m not having any damn femoral popliteal bypass operation,” he told me. “Every single one of those patients dies.”

Dr. Peter Rossi
While that may be an exaggeration, it raises a concern about traditional surgery when endograft repair is an option.

Endograft repair is a technique that is reaching its prime, as a growing number of reports have shown – although none of these studies has large numbers because the volume just isn’t available. One recent paper compared 52 open and 23 endovascular PAA repairs (Ann Vasc Surg. 2016 Jan;30:253-7) and found both had similarly high rates of reintervention – 50% at 4 years. But it is noteworthy that the endovascular results improved with time.

A University of Pittsburgh study of 186 open and endovascular repairs found that patients with acute presentations of embolization or aneurysm thrombosis did better with open surgery. In addition, while open repair had superior patency initially after surgery, midterm secondary patency and amputation rates of open and endovascular repair were similar (J Vasc Surg. 2016 Jan;63[1]:70-6).

A Netherlands study of 72 PAA treated with endografting showed that 84% had primary patency at 1 year, and 74% had assisted primary patency at 3 years (Eur J Vasc Endovasc Surg. 2016 Jul;52[1]:99-104). Among these patients, 13 had late occlusions, 7 were converted to bypass, and 2 required thrombolysis; but none required limb amputation.

A meta-analysis of 540 patients found no statistically significant difference in outcomes between endovascular and open repair for PAA (Eur J Vasc Endovasc Surg. 2015 Sep;50(3):351-9). Another systematic review and meta-analysis of 14 studies and 514 patients also found no difference in pooled primary and secondary patency at 5 years (J Endovasc Ther. 2015 Jun;22[3]:330-7).

There certainly are contradictory studies, such as one by Dr. Alik Farber’s group in Boston that showed open repair is superior to endovascular surgery (J Vasc Surg. 2015 Mar;61[3]:663-9); but retrospective database mining certainly has its limitations. Their retrospective study queried the Vascular Quality Initiative database and found that 95% of patients who had open elective popliteal aneurysm repair were free from major adverse limb events, vs. 80% for endovascular treatments.

The best outcomes of open repair happen with autologous vein, but there is precious little of that around now. Emergency patients would probably do better with open surgery, but in elective repair there is no clear differential data.

So, if that’s the case, I’m going to take the small incision.

Peter Rossi, MD, FACS, is an associate professor of surgery and radiology, and the clinical director of vascular surgery, at the Medical College of Wisconsin, Milwaukee. He is also on staff at Clement J. Zablocki Veterans Affairs Medical Center in Milwaukee. Dr. Rossi had no financial relationships to disclose.

Endovascular repair may not be durable

Debating the durability of elective endovascular repair of popliteal artery aneurysm raises a question: Who determines durability anyway?

Is it the patients who only want the Band-Aid and no incision? I don’t think so. Is it the interventionalist who only does endovascular repairs? I don’t think so. I’m sure it’s not the insurance companies, who only worry about cost containment, either.

So, who should determine durability of endovascular popliteal artery aneurysm (PAA) repair?

Dr. Patrick Muck
How about vascular surgeons? That’s a novel concept. We have a long history of treating PAA and evaluating prospective randomized data in general. At the end of the day, endograft technology for PAA treatment must be compared against open aneurysm repair in a prospective, randomized trial.

So, the question is, do we have such data?

There are multiple reports looking at how well open repair works. It has been done for decades. In 2008, a Veterans Affairs study of 583 open PAA repairs reported low death rates and excellent rates of limb salvage at 2 years, even in high-risk patients (J Vasc Surg. 2008 Oct;48[4]:845-51). Open surgical repair has excellent documented durability, and that is not the question at hand.

Endovascular repair has some presumed advantages. It’s less invasive and involves less postoperative pain and a quicker recovery. But it is not without problems – graft thrombosis and occlusion, endoleaks, distal limb ischemia, and stent fractures among them.

Surgery, to be clear, is not perfect, either. One of my patients who years ago presented with an occluded PAA underwent open bypass repair – but then went on later to have a pseudoaneurysm of the proximal anastomosis. I repaired this with an endograft, and he has done quite well. So, we all do endograft repairs, walk out, chest bump the Gore rep, and send the patient home that day.

Is it durable, though?

Most of the data on endovascular repair are from single-center studies dating back to 2003. There’s only one prospective trial comparing endovascular vs. open repair (J Vasc Surg. 2005 Aug;42[2]:185-93), but it was a single-center trial with a severe power limitation, because it involved only 30 patients. It found endovascular repair was comparable to open surgery. Also, I suspect a great deal of selection bias is involved in studies of endovascular repair.

A number of studies have found endovascular repair is not inferior to surgical repair. For example, a study by Dr. Audra Duncan, at Mayo Clinic, and her colleagues found that primary and secondary patency rates of elective and emergent stenting were excellent – but the study results only extended out to 2 years (J Vasc Surg. 2013 May;57[5]:1299-305). I don’t think we could hang our hat on that.

A Swedish study that compared open and endovascular surgery in 592 patients reported that endovascular repair has “significantly inferior results compared with open repair,” particularly in those who present with acute ischemia (Eur J Vasc Endovasc Surg. 2015 Sep;50[3]:342-50). A close look at the data shows that primary patency rates were 89% for open repair and 67.4% for stent graft.

Referencing the systematic review and meta-analysis that Dr. Rossi cited, the primary patency of endovascular repair was only 69% and the secondary patency rate was 77% at 5 years (J Endovasc Ther. 2015 Jun;22[3]:330-7). As physicians, I submit that we can do better.

A Netherlands study investigated stent fractures, finding that 17% (13 out of 78 cases) had circumferential fractures (J Vasc Surg. 2010 Jun;51[6]:1413-8). This study only included circumferential stent fractures and excluded localized strut fractures. I think these studies show that endovascular repair is not always durable.

I want to remind you that we are vascular surgeons, so it is appropriate for us to embrace surgical bypass and its known durability, especially when the durability of endovascular repair is still not known.

Patrick Muck, MD, is chief of vascular surgery and director of vascular residency and fellowship at Good Samaritan Hospital, Cincinnati. He is also on staff at Bethesda North Hospital, Cincinnati, and is affiliated with TriHealth Heart Institute in southwestern Ohio. Dr. Muck had no financial relationships to disclose.

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