Development of a Biological Stent Graft for Aorta Aneurysm Repair

DESCRIPTION (provided by applicant): Abdominal aorta aneurysms (AAA) are diagnosed in more than 100,000 patients in the U.S. each year. About 70% of these patients require surgical intervention to prevent aneurysm progression. Nearly 20 years ago, Parodi revolutionized AAA treatment and repair by using an ePTFE stent graft that could be delivered via an endovascular approach. Today, more than 35,000 AAA stent grafts are placed annually, making AAA repair devices a 700 million industry in the U.S. alone. Despite the rapid adoption of endovascular repair, the devices are associated with a significant failure rate (more than 20% at one year). The majority of these failures are caused by leakage around or through the device. This type of endoleakage is caused by relative motion between the stent graft device and the native aorta. This relative motion is aggravated by the fact that the stent grafts are static devices that cannot remodel as the native aorta moves and remodels dynamically. Moreover, most stent grafts are wrapped in ePTFE (Teflon), which works well as a blood contacting surface, but does not adhere well to the surrounding tissue. We hypothesized that by replacing the ePTFE covering on a stent graft with a biological sheet, we might improve upon the fixation of the device into the native aorta. That is, by providing a natural collagen substrate which would support cell ingrowth and tissue adhesion, we would increase the bonding strength between the device and the native aorta. We termed this approach biological neck fixation. The objective of this Phase I grant is to demonstrate the initial feasibility of biological neck fixation such that we can more appropriately justify expanded efficacy studies in Phase II. Specifically, in Phase I, we will: develop a sheet built from canine cells that closely matches the mechanical properties of human sheets that we have developed previously (Specific Aim 1); implant the biological stent graft via a 10 French catheter in a canine model to evaluate durability, morphology, and histological properties (Specific Aim 2.1); and compare the adhesion and anchoring properties of biological stent grafts relative to the standard of care in a canine model (Specific Aim 2.2). Exclusion of the AAA without signs of migration or endoleakage at 3 months post-implant, and equal or greater anchoring strength relative to ePTFE stent grafts will be the key milestones to justify advancing to Phase II. The long-term objective of this project will be to commercialize a completely biological stent graft that can remodel with the host aorta, thereby reducing the overall failure rate relative to the current standard of care. PUBLIC HEALTH RELEVANCE: Abdominal aorta aneurysms (AAA) are diagnosed in more than 100,000 patients in the U.S. each year, and are the 13th leading cause of death. Today, more than 35,000 AAA endovascular stent grafts are placed annually, making AAA repair devices a 700 million industry in the U.S. alone. This Research Proposal describes a new repair device which may significantly reduce the relatively high failure rates associated with the standard of care in AAA repair.