EVAR in a High-Volume, Multisurgeon Practice

In the last 20 years, the treatment of abdominal aortic aneurysms has been revolutionized by endovascular repair. To date, there have been seven endografts approved by the US Food and Drug Administration for commercial use. Our group has had experience with many of these devices. Clinical outcomes, ease-of-use, and cost concerns have driven our practice to the preferential use of the GORE® EXCLUDER® Device (Gore & Associates, Flagstaff, AZ). In the past 5 years, we have performed 748 endovascular aneurysm repairs (EVAR) procedures using the GORE® EXCLUDER® Device as our primary graft for both complex and straightforward aneurysm repair.

EFICIENT PROCEDURAL TIMES

The Vascular Institute at Oklahoma Heart Hospital is a comprehensive peripheral vascular program located in Oklahoma City, Oklahoma. It is one of the most active vascular surgery specialty groups in the region, dedicated to providing the highest levels of patient care using the most current technologies for the treatment of vascular disease. Minimized procedural times and component usage are important to a successful private practice. The elegance and simplicity of the GORE® EXCLUDER® Device facilitate a reduction in procedure times, thereby improving operative efficiency and minimizing anesthesia times.

Extensive case planning and surgical team training have allowed us to achieve an average procedure time of approximately 40 minutes from incision to closure of the skin. Short operative times play a crucial role in our ability to successfully treat challenging aortic aneurysm pathologies via an endovascular approach. Additionally, the ability to treat patients with a minimal number of components greatly simplifies case planning and procedural complexity. In the majority of our cases, the GORE® EXCLUDER® Device requires only two pieces for complete aneurysm exclusion. In the event that an extension is required to promote seal, it can be delivered and deployed accurately and rapidly.

DEVICE SEAL, MIGRATION, AND PATENCY

In our broad experience, we have seen very few intraoperative proximal or distal type I endoleaks. In the case of delayed or small blush type I leaks, we adopt a “wait-to-treat” approach and find that the majority resolve before the patient's scheduled 30-day follow-up computed tomography, resulting in a very low rate of secondary intervention. This is consistent with large, multicenter registry data, as well as randomized controlled trials in which the GORE® EXCLUDER® Device has been shown to be associated with statistically significant lower reintervention rates compared to all other endografts.^1,2

One significant issue among many early endografts has been failed fixation. Endograft migration has led to catastrophic complications, including aneurysm rupture and conversion to open surgical repair.

Manufacturers and physicians have made claims that devices with suprarenal fixation have inherent superior fixation and a lower incidence of graft migration. These assumptions, largely based on first-generation device performance, have been refuted through various trials and clinical studies. More accurately, devices that rely solely on radial force and graft wall/aorta contact are devices that struggle with migration.

A review of published literature establishes the durability and effectiveness of infrarenal active fixation with the GORE® EXCLUDER® Device.2-8 This infrarenal fixation avoids the clinical risks associated with suprarenal stents, both in terms of renal function and endograft delivery. A recent review has indicated that suprarenal fixation poses an increased risk of renal injury.9 Several reports of suprarenal delivery system failures have shown that the added stent row and its delivery/release mechanism increases procedural complexity. Additionally, a taller, rigid suprarenal stent can actually work against graft seal by holding it away from the aortic wall, especially in angulated anatomies. The highly flexible GORE® EXCLUDER® Device with shorter stents and infrarenal fixation constantly conforms to challenging anatomy, thus promoting seal.

We simply do not see migration of the GORE® EXCLUDER® Device when used within the instructions for use, and we do not believe that suprarenal fixation offers any advantage, even in the treatment of complex proximal neck anatomy. Our results have been superior in both migration resistance and seal as compared to the published results of suprarenal devices.

LIMB PERFORMANCE

Limb thrombosis/kinking of the EVT device (Endovascular Technologies, Inc., a subsidiary of Guidant Corporation) led to the incorporation of supported stents within endograft limbs. It was believed that supported limbs were essential to optimal clinical performance. Since the EVT graft, different stent features have been incorporated to try to obtain flexibility, as well as longitudinal and radial support. Some device limbs have individual rings or even spiral stents but leave regions of unsupported graft that can bunch into the graft lumen in angulated anatomy. Others have longitudinal wires to provide longitudinal support for delivery accuracy and to limit graft accordioning; however, these wires limit device flexibility.

The sutureless, nested stents and polytetrafluoroethylene material of the GORE® EXCLUDER® Device limbs provide full radial and longitudinal support without sacrificing device flexibility. Clinical results have demonstrated the superiority of the GORE® EXCLUDER® Device limbs in clinical performance. In our 748 patients treated with the GORE® EXCLUDER® Device, we have experienced just one limb occlusion, which was a result of placing a bifurcated graft within a flow lumen that only measured 14 mm in diameter. The GORE® EXCLUDER® Device limbs are the most kink- and occlusion-resistant limbs of the currently available devices.^2,10-13

CONTROL AND PRECISION OF DELIVERY

The addition of the GORE® C3 Delivery System (Gore & Associates) has further enhanced our ability to treat patients with complex aortic neck anatomy (Figure 1). The ability to reposition the graft after device deployment, when the proximal half of the graft is in complete contact with the aortic wall, has allowed us to be more aggressive when placing the graft as close to the renal ostium as possible. The majority of our deployments are done with sufficient accuracy so that we do not have to reposition the graft, but the GORE® C3 Delivery System provides security against any miscalculation or anatomical complexity.

One of the unique features of the GORE® C3 Delivery System is that it accommodates different modes of device release from the catheter. As published by Alterman et al, Minion et al, and Krajcer et al, the constraining sleeve deployment allows the graft to fall away from the catheter to more easily accommodate angulated anatomy.^14-16 After constraining the device to the catheter upon initial deployment, the graft is released from the catheter in a concentric fashion. Whether using the original GORE® SIM-PULL Delivery System (Gore & Associates) or GORE® C3 Delivery System, operators can use the unique deployment attributes to their advantage, which is very accommodating for physicians within the same group who may have different preferences for treating different patients.¹⁷

ACCES

When access is difficult because of small or tortuous iliac arteries, the on-catheter flexibility of the device enables device tracking (Figure 2). Our practice is to attempt different techniques that will allow endovascular repair without the use of a standard iliac conduit unless necessary. More often than not, the introducer dilator/sheath can be navigated through the vessels so that safe and accurate deployment can occur. However, adjunctive maneuvers are sometimes required. When using larger sheaths (18 or 20 F), gentle balloon angioplasty of the iliac arteries allows enough room so that the dilator/sheath can be placed. When balloon angioplasty is not effective, we have utilized a 7- or 8-mm GORE® VIABAHN® Stent (Gore & Associates) as an “endoconduit” to aid in delivery.¹⁵ We have rarely encountered perforations of the iliac artery or other traumatic injuries. Additionally, using a delivery sheath for access allows for one sheath introduction that protects the femoral artery from iatrogenic injury during the subsequent catheter, device, and balloon exchanges.

TOTALY PERCUTANEOUS EVAR

Although the majority of our EVAR procedures are performed through standard bilateral common femoral cutdowns, we sometimes perform them via a totally percutaneous approach utilizing closure devices in patients with suitable anatomy. Unsuccessful closure with a closure device does require patients to undergo open repair of the femoral artery, but we have not encountered any problems with the GORE® EXCLUDER® Device when attempting percutaneous EVAR. This is consistent with the US Food and Drug Administration trial of the GORE® EXCLUDER® Device, which was the first EVAR approval study in the United States to incorporate this technique.¹⁶

DURABILITY

EVAR clinical trial results have called into question the long-term benefit of endovascular repair because of problems related to endograft durability and endograft revision. It is possible that this is, in part, a result of the endografts selected. Studies have reported device failures related to migration, patency, and endoleak. As manufacturers have worked to lower the profile of their devices, fabrics used have become thinner and thinner.

Reports of graft fatigue of newly released endografts have already been published.¹⁷ This has also shown clinical relevance in type IV endoleaks and aneurysm sac pulse pressure.^18,19 In these publications, the GORE® EXCLUDER® Device was shown to have a more durable response. This is most likely due to the unique construction of the graft. The GORE® EXCLUDER® Device is the only endograft that does not rely on sutures to tie the graft to the stent. Gore uses a sutureless construction to bond the stent with ePTFE film to create a single, seamless laminate abrasion-resistant graft. The durability of this construction has been confirmed through many long-term clinical studies as well as our personal experience.^20-22 Extensive case planning, clinical support, and device design have minimized complications and provided our patients with an excellent long-term repair.

CURRENT LIMITATIONS

Product line extensions have been added to the GORE® EXCLUDER® Device line to augment the number of patients who can be treated with this device. Most recently, larger limbs extended treatment to patients with iliacs as large as 25 mm. Still, there remains a small subset of patients who cannot be treated due to anatomical restrictions, such as patients with aortic necks > 29 mm in diameter. We look forward to this summer's anticipated release of the larger GORE® EXCLUDER® Device trunk, designed to treat inner aortic diameters up to 32 mm, as well as projects to lower the portfolio's profile.

CONCLUSION

Treatment of straightforward and challenging anatomy with the GORE® EXCLUDER® Device is technically feasible and clinically effective. Device performance and ease-of-use have made it the standard of care for EVAR in our facility. It has proven to be a durable and reliable endograft and has enabled us to treat a wide variety of patients and pathologies.

Jim G. Melton, DO, is Director of the Vascular Institute at Oklahoma Heart Hospital in Oklahoma City, Oklahoma. He has disclosed that he has no financial interests related to this article.

Kousta I. Foteh, MD, is with the Department of Vascular Surgery, Oklahoma Vascular Institute, Oklahoma Heart Hospital in Oklahoma City, Oklahoma. He has disclosed that he has no financial interests related to this article. Dr. Foteh may be reached at kfoteh@okheart.com.

1. Brown LC, Greenhalgh RM, Powell JT, Thompson SG; EVAR Trial Participants. Use of baseline factors to predict complications and reinterventions after endovascular repair of abdominal aortic aneurysm. Br J Surg. 2010;97:1207-1217.
2. van Marrewijk CJ, Leurs LJ, Vallabhaneni SR, et al; EUROSTAR collaborators. Risk-adjusted outcome analysis of endovascular abdominal aortic aneurysm repair in a large population: how do stent-grafts compare? J Endovasc Ther. 2005;12:417-429.
3. Kibbe MR, Matsumura JS; Excluder Investigators. The Gore Excluder US multi-center trial: analysis of adverse events at 2 years. Sem Vasc Surg. 2003;16:144-150.
4. Peterson BG, Matsumura JS, Brewster DC, Makaroun MS; Excluder Bifurcated Endoprosthesis Investigators. Five-year report of a multicenter controlled clinical trial of open versus endovascular treatment of abdominal aortic aneurysms. J Vasc Surg. 2007;45:885-890.
5. Haider SE, Najjar SF, Cho JS, et al. Sac behavior after aneurysm treatment with the Gore Excluder low-permeability aortic endoprosthesis: 12-month comparison to the original Excluder device. J Vasc Surg. 2006;44:694-700.
6. Curci JA, Fillinger MF, Naslund TC, Rubin BG; for the Excluder Bifurcated Endoprosthesis Investigators. Clinical trial results of a modified gore excluder endograft: comparison with open repair and original device design. Ann Vasc Surg. 2007;21:328-338.
7. Dillavou ED, Muluk S, Makaroun MS. Is neck dilatation after endovascular aneurysm repair graft dependent? Results of 4 US Phase II trials. Vasc Endovasc Surg. 2005;39:47-54.
8. Leurs LJ, Hobo R, Buth J; EUROSTAR Collaborators. The multicenter experience with a third-generation endovascular device for abdominal aortic aneurysm repair. A report from the EUROSTAR database. J Cardiovasc Surg. 2004;45:293-300.
9. Noorani A, Walsh SR, Boyle JR. Long-term effects of EVAR. Suprarenal versus infrarenal fixation. J Cardiovasc Surg (Torino). 2011;52:199-203.
10. Hingorani AP, Ascher E, Marks N, et al. Iatrogenic injuries of the common femoral artery (CFA) and external iliac artery (EIA) during endograft placement: an underdiagnosed entity. J Vasc Surg. 2009;50:505-509; discussion 509.
11. Bos WT, Tielliu IF, Van Den Dungen JJ, et al. Results of endovascular abdominal aortic aneurysm repair with selective use of the Gore Excluder. J Cardiovasc Surg. 2009;50:159-164.
12. Mendonça CT, de Carvalho CA, Weingärtner J, et al. Endovascular treatment of abdominal aortic aneurysms in highsurgical- risk patients using commercially available stent-grafts. J Endovasc Ther. 2010;17:89-94.
13. Maleux G, Koolen M, Heye S, Nevelsteen A. Limb occlusion after endovascular repair of abdominal aortic aneurysms with supported endografts. J Vasc Interv Radiol. 2008;19:1409-1412.
14. Alterman DM, Stevens SL. The excluder aortic endograft. Perspect Vasc Surg Endovasc Ther. 2008;20:136-148; discussion 149-157.
15. Peterson BG, Matsumura JS. Internal endoconduit: an innovative technique to address unfavorable iliac artery anatomy encountered during thoracic endovascular aortic repair. J Vasc Surg. 2008;47:441-445.
16. Matsumura JS, Katzen BT, Hollier LH, Dake MD. Update on the bifurcated EXCLUDER endoprosthesis: phase I results. J Vasc Surg. 2001;33:S150-153.
17. Abouliatim I, Gouicem D, Kobeiter H, et al. Early type III endoleak with an Endurant endograft. J Vasc Surg. 2010;52:1665-1667.
18. Baum RA, Stavropoulos SW, Fairman RM, Carpenter JP. Endoleaks after endovascular repair of abdominal aortic aneurysms. J Vasc Interv Radiol. 2003;14:1111-1117.
19. Shrikhande G, Khan S, Hussain H, et al. Significance of initial aortic aneurysm pressure sensor readings varies with aortic endograft design. World J Surg. 2010;34:2969-2972.
20. Kim YI, Chung JW, Kim HB. Placement of Endovascular Stent across the Branching Arteries: Long-term Serial Evaluation of Stent-tissue Responses Overlying the Arterial Orifices in an Experimental Study. Cardiovasc Intervent Radiol. [published online ahead of print August 9, 2011]
21. van Marrewijk CJ, Leurs LJ, Vallabhaneni SR, et al. Risk-adjusted outcome analysis of endovascular abdominal aortic aneurysm repair in a large population: how do stent-grafts compare? J Endovasc Ther. 2005;12:417-429.
22. Peterson BG, Matsumura JS, Brewster DC, et al. Five-year report of a multicenter controlled clinical trial of open versus endovascular treatment of abdominal aortic aneurysms [published online ahead of print March 28, 2007]. J Vasc Surg. 2007;45:885-890.