Gore Excluder

Introduction

Endovascular aortic repair (EVAR) has become the standard of care in the treatment of infrarenal abdominal aortic aneurysm (AAA), with low perioperative morbidity and mortality and comparable long-term outcomes to open surgical repair. Successful EVAR requires meticulous intraoperative execution and careful consideration of a variety of anatomic factors during preoperative planning. Of these anatomic features, perhaps the most important are the characteristics of the infrarenal aortic neck. Hostile proximal neck anatomy, in the form of severe angulation, copious thrombus or calcification, or short overall length, is associated with worse short- and long-term outcome after EVAR. In order to improve these outcomes, continuous technological innovation in EVAR has focused on broadening the anatomic applicability of currently available devices and improving endograft performance in the infrarenal neck. These advances and a steadily increasing comfort level with EVAR among vascular specialists have led to an increasing number of aortic stent grafts placed over the past 10 years, with a significant percentage placed outside device specific indications for use (IFU). Given this trend of EVAR application in cases with challenging anatomy, the use of a repositionable stent graft offers several potential advantages, including increased deployment accuracy, potentially reduced procedure and fluoroscopy time, and a potential cost reduction by reduced need for aortic cuffs following inaccurate initial deployment or to treat proximal endoleak. With these potential advantages novel complications also emerge, specific to intraoperative repositioning of the device. This chapter will examine the unique attributes and potential complications of the only commercially available, repositionable device for EVAR, the Gore Excluder with its C3 delivery system (W.L. Gore & Associates, Flagstaff, AZ).

Evolution of the Gore Excluder AAA Endoprosthesis

Since the introduction of EVAR, technological innovation has focused on increased anatomic applicability of respective stent grafts and on improved short- and long-term outcomes following aortic repair. The Gore Excluder, now in its third iteration, has been implanted in over 300,000 patients and has undergone several design modifications and improvements since its initial FDA approval in 1997. The first major improvement, in 2004, was the modification of the original ePTFE (expanded polytetrafluoroethylene) microstructure, reducing porosity and subsequent fluid transmigration. The newer, low permeability Excluder was shown not only to reduce the incidence of sac enlargement and associated endotension, but also to promote early aneurysm sack shrinkage. Although known for its inherent overall flexibility and performance in challenging iliac anatomy, accurate proximal deployment of the Excluder still remained a concern among clinicians.

A critical second modification to the Excluder was the complete redesign of the traditional “rip-cord” mechanism or sim-pull technology of proximal graft deployment, which was occasionally imprecise in the setting of severe proximal neck angulation, to a repositionable deployment system. The modified C3 delivery system allows the operator to reconstrain the proximal aspect of the stent graft twice and reposition the device before final deployment. This novel feature means the graft can be repositioned when the proximal aspect of the main body graft fabric lands either too far proximally or too far distally with respect to the lower renal artery. The proximal aspect of the stent graft is constrained to approximately 30% of its full diameter, withdrawing the proximal anchors away from the aortic wall and allowing proximal or distal adjustment. In addition, when contralateral gate catheterization is challenging, the proximal aspect of the stent graft can be reconstrained and the graft rotated to allow a more favorable orientation.

Excluder with C3 Delivery System Deployment

Deployment of the Excluder with C3 delivery system occurs with three sequential steps: (1) opening of the main body and contralateral gate; (2) removal of the constraining wire and loop; and (3) deployment of the ipsilateral limb.