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Published on September 01, 2018

Clinical Trial Evaluates New Endovascular Aneurysm Sealing System

Anatomy Nellix Hero

With EVAS technology, polymer-filled endobags surround
two balloon-expandable stents to stabalize aneurysms.

North Kansas City Hospital is one of only six hospitals in the country currently recruiting patients for a clinical trial that uses endovascular aneurysm sealing to repair infrarenal abdominal aortic aneurysms. Endologix Nellix® technology stabilizes aneurysms with polymer-filled endobags that surround two balloon-expandable polytetrafluorethylene-covered stents.

This innovative system provides an alternative to endovascular aortic aneurysm repair. “The Nellix EVAS is the most significant change in aneurysm repair technology we’ve seen in the past 20 years,” said Scott W. Kujath, MD, FACS, a vascular surgeon with the Midwest Aortic and Vascular Institute. “From what we’ve seen in initial data from Europe and the U.S., EVAS is a durable repair. For some patients, it’s a better repair than other devices."

Clinical Trial

Dr. Kujath is the principal investigator for the NKCH arm of this prospective safety and efficacy clinical trial. To ensure adequate enrollment, the study sites were selected for research infrastructure and physician experience in endovascular aneurysm repair.

Dr. Kujath and his MAVI colleagues perform the procedures. To qualify for the clinical trial, patients must have an abdominal aortic aneurysm with either a ≥ 5.0 cm sac diameter or a ≥ 4.5 cm sac diameter that has increased by
> .5 cm in the last six months.

The Procedure

During the 90-minute procedure, the surgeon guides two Nellix stents with integrated endobags through each of the femoral arteries and deploys the stents adjacent to the lowermost renal artery and proximal to the internal iliac artery. The surgeon simultaneously fills the endobags with saline to determine volume, removes the saline and inflates the bags with polymer.

As the endobags fill with polymer, the bags expand to fill the aneurysm sac. “These endobags make the stents more rigid so they are less likely to move over time,” Dr. Kujath said. “This also helps seal the side branches of the aneurysm sac, eliminating one of the risks for failure that we see with other stent grafts."

Post-implantation, patients undergo CT angiography within three months and at follow-up intervals. Follow-up visits occur at 30 days, six months and annually for five years to assess aneurysm morphology, device status and
lab results.

EVAR Versus EVAS

Since EVAR was first performed in 1990, the procedure has reduced perioperative morbidity and mortality when compared with open surgical aneurysm repair. Although less invasive than open surgical repair, EVAR patients can experience complications that require secondary interventions.

Dr. Kujath pointed to research that showed EVAS patients had a higher three-year survival rate (93%) than traditional EVAR patients (88%). Investigators compared 333 patients from the U.S. Investigational Device Exemption Trial for the Endovascular Aneurysm Sealing with 15,431 patients from the Vascular Quality Initiative database who underwent EVARs in 2014-2016.

EVAS Versus EVAR Survival
AAA Size EVAR EVAS
< 5.5 cm 94% 91%
≥ 5.5 cm 86% 92%
Source: Schermerhorn M, et al. Late-breaking Aortic Trials, Charing Cross International Symposium; April 24-27, 2018; London.

Next Steps

Dr. Kujath is optimistic about the potential for extending the capacity of EVAS. “It will give us an alternative for fixing aneurysms that involve the branches of the arteries of the aorta,” he said. “We could put stents in those arteries and run the polymer higher in the aorta. This is not part of our initial study, but the FDA is working toward getting approval. It’s called chimney endovascular aneurysm sealing.”

His appreciation of what is in store for patients is deeply rooted. His grandmother died of a ruptured aneurysm. “I love that we can do this with stents,” Dr. Kujath said. “When technology improves, patient stays in the hospital are shorter and they get better more quickly.”

Scott W. Kujath, MD, FACS

Scott W. Kujath, MDDr. Kujath earned his medical degree from the University of Missouri-Kansas City School of Medicine, where he completed his general surgery residency. He did his fellowship training in vascular surgery at the University of Tennessee, Memphis.