Perspectives from two veteran vascular surgeons
Just two decades ago, the only treatment for an abdominal aortic aneurysm (AAA) was open surgery. Today, seven FDA-approved endograft devices provide many patients with a minimally invasive alternative.
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Cleveland Clinic vascular surgeons participated in trials that led to the approval of nearly every new AAA repair device on the market, and they continue to contribute to refinements in AAA management. Two of those surgeons recently shared with Consult QD their insights on five leading issues and developments in AAA repair.
Lee Kirksey, MD
In a recent study (J Vasc Surg. 2014;60:876-883), Endologix’s AFX® Endovascular AAA System extended the proximal neck seal by about 5 mm in 70 percent of enrolled patients. Based on these promising data, the multicenter LEOPARD trial has been launched to compare the AFX device with other endograft devices in a real-world setting. In fact, LEOPARD will be the first industry-sponsored randomized trial to pit different FDA-approved devices for endovascular aneurysm repair (EVAR) against one another. Target enrollment is 800 patients across up to 80 centers. Follow-up will continue for five years.
Cleveland Clinic vascular surgeon Lee Kirksey, MD, believes LEOPARD has the potential to answer questions about which device best treats patients. “This is the first time we’re getting a sense of head-to-head comparisons of innovative, minimally invasive devices to treat aneurysm disease,” he says.
While endografts have revolutionized AAA treatment, especially for community physicians, open surgery may still be the best option for patients with complex aortic anatomy. Cleveland Clinic performs many open surgeries for AAA patients with unfavorable anatomy or after endograft devices have failed.
Sean Lyden, MD
“We have the world’s largest experience in treating failures of endovascular technologies,” says Sean Lyden, MD, Chairman of Cleveland Clinic’s Department of Vascular Surgery. “We see two modes of failure: early from use in unfavorable anatomy, and late from aortic disease progression and device failure (J Vasc Surg. 2014;59:886-893). We are uniquely able to perform minimally invasive fenestrated repair in some and open removal in others (J Vasc Surg. 2014;59:1479-1487).”
Younger and healthier AAA patients may also find open surgery to be a better option. For one, the lifelong surveillance needed for endovascular repair poses a small but real cancer risk due to radiation from CT scans (Acta Radiol. 2016 Jun 8 [Epub ahead of print] and J Cardiovasc Surg (Torino). 2010;51:95-104). Additionally, endograft devices have been tested to last through a simulated 10-year life cycle, but many young and healthy AAA patients will live significantly longer than that. “We are now seeing some devices failing after 10 years and requiring removal,” notes Dr. Lyden. “Yet removal of the device is associated with more complications and risk of death compared with open native AAA repair.”
About 15 to 20 percent of AAA patients receiving an endograft will still have a flow into the aneurysm sac from the lumbar arteries or the inferior mesenteric artery (i.e., a type II endoleak) at one year. Type II endoleaks require treatment when growth of the aneurysm is found. “Even when the aneurysm is not growing, a type II endoleak can be a cause of anxiety to the patient over the durability of the repair,” explains Dr. Lyden. “We spend a lot of time reassuring the patient that treatment is not needed in many cases.”
However, a promising new EVAR device under investigation at multiple sites, including Cleveland Clinic, has been shown to markedly reduce the presence of type II endoleaks (J Vasc Surg. 2016;63:23-31). The Nellix® EndoVascular Aneurysm Sealing System (Endologix) employs a unique mechanism using a polymer with the consistency of a pencil eraser to fill and seal the sac. The polymer also takes the pressure off the aortic wall sealing the aneurysm sac.
“It’s difficult not to be enthusiastic about the Nellix device,” Dr. Kirksey says. “The idea that we may substantially mitigate the rate of type II endoleaks is exciting.”
Dr. Lyden notes that early data point to “the elimination of concern over type II endoleaks” for many patients. “The approach of creating a sealing of the sac is unique,” he says. “Secondary embolization procedures for type II endoleaks might become a thing of the past.”
It’s generally understood that patients with an AAA below a certain diameter may not need immediate treatment. Dr. Lyden says Cleveland Clinic surgeons generally treat aneurysms larger than 5.5 cm in diameter in men, based on findings of the UK Small Aneurysm Trial (Br J Surg. 2007;94:702-708) and the ADAM trial (Arch Intern Med. 2000;160:1425-1430). He treats aneurysms down to 5 cm in women, for whom better data on when best to treat are lacking.
Dr. Kirksey, citing the PIVOTAL trial (J Vasc Surg. 2010;51:1081-1087), says aneurysms in the 5- to 5.5-cm range can be considered for treatment, especially given the low mortality rates for minimally invasive surgery. But age matters, too. “For patients in their 50s or 60s,” he says, “you need to have a frank discussion of the long-term risks of endovascular stent graft failure, which loom larger for younger patients with longer life expectancy (N Engl J Med. 2015;373:328-338). Because you’re talking about the potential for problems over a 20-year window, younger patients must fully understand all their options and be offered the option of open repair.”
“We’ll continue to be involved in the development and evaluation of new minimally invasive endovascular devices for treating aortic aneurysms,” adds Dr. Lyden. “However, the ideal way to offer excellent care for patients is by selecting the specific therapy best suited to each patient’s individual needs, whether it’s an endovascular approach, a larger open procedure or a combined approach. By drawing on Cleveland Clinic’s decades of experience as a national leader in treatment of aortic aneurysmal disease, we are equipped to offer patients whichever procedure they’re most likely to fare well with.”
Patients who do receive a device are often treated outside FDA-approved instructions for use. Dr. Kirksey notes that increasing evidence suggests that off-label use yields inferior results (Surg Today. 2015;45:880-885). This was first observed by former Cleveland Clinic vascular surgeon Roy Greenberg, MD, who published findings (Circulation. 2011;123:2848-2855) that compliance with EVAR device guidelines was low and post-EVAR aneurysm sac enlargement was high, raising concern for long-term risk of aneurysm rupture.
Dr. Kirksey says the success of off-label use depends on the particular circumstances, with the proximal neck between the renal arteries and the start of the aneurysm proving to be a particularly fraught region. “If that segment of the aorta is diseased or doesn’t have adequate length or reasonable circumference to be treated with a standard endograft,” he notes, “then the patient is going to have more issues.”
He adds that going off-label might be reasonable for sicker patients or those with limited life expectancy. But for healthy patients, alternatives like open surgery or a fenestrated or branched device should be considered.
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