Resistance to Aortic Endograft Migration: Comparative Effectiveness of FDA Approv

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DESCRIPTION (provided by applicant): This application addresses broad Challenge Area (05) Comparative Effectiveness Research (CER) and specific Challenge Topic 05-EB-105: Comparative Effectiveness of Medical Implants. The prevalence of abdominal aortic aneurysms (AAA) has increased significantly in the American population, affecting 5-7% of Americans over age 60. During the past decade endovascular aneurysm repair has become the primary treatment for aneurysm disease. Currently, there are 5 FDA approved abdominal aortic aneurysm endografts: Medtronic AneuRx, Gore Excluder, Cook Zenith, Endologix Powerlink, and Medtronic Talent. Each of these devices presents different designs and fixation mechanisms. Endovascular repair is a minimally invasively procedure that reduces perioperative morbidity and mortality when compared to open repairs. However, endovascular procedures are prone to late failure due to the loss of long-term positional stability (i.e., migration) of the endograft as a result of the pulsatile forces of blood flow. Endograft failure results in costly secondary procedures, conversion to open repair, long-term surveillance, and death. Understanding the biomechanical environment experienced by endografts in vivo is a critical factor to ensure correct functioning and long term durability of the device. The goal of this work is two-fold: First, we will develop and apply a set of tools to characterize the mechanical behavior of endografts in vivo with the overall goal of determining the likelihood of migration of the endograft. Second, we will perform a comparative effectiveness study with regards to migration of the 5 AAA endografts. We will use 3D segmentation techniques to generate patient- specific computer models of AAAs with implanted endografts. Then, we will perform Computational Fluid Dynamics (CFD) analyses to evaluate the hemodynamic forces acting on the device. The CFD analysis will rely on sophisticated methods for boundary condition specification to obtain realistic distributions of flow and pressure in the computer model of the endograft. We will then perform a Computational Solid Mechanics (CSM) analysis to evaluate the fixation forces developed by the endograft in the attachment zones with the vessel wall. Longitudinal studies of serial follow-up imaging of patients treated with each endograft will provide the necessary statistical data to obtain a likelihood of migration for the computational studies. The research team we have assembled consists of leading bioengineers, mechanical engineers, radiologists, and clinicians and will be led by Dr Christopher K. Zarins at Stanford, a leading researcher in the development and clinical application of endovascular treatments for AAA disease. Dr. Zarins has been a strong advocate for using imaging and simulation tools to improve medical device design and develop safer and more effective medical products. This research will be the first attempt to characterize the problem of migration of AAA endografts using a combination of best-in-class imaging, CFD and Computational Solid Mechanics tools. Furthermore, this work will provide the first comparative effectiveness study of the 5 current FDA approved AAA endografts. Resistance to aortic endograft migration: comparative effectiveness of FDA approved devices. Public Health Relevance: Endovascular repair has become the primary treatment for abdominal aortic aneurysm (AAA) disease. There are currently 5 FDA approved endograft devices for AAA repair. The true in-vivo biomechanical environment experienced by these devices is poorly understood. Furthermore, there are currently no studies that compare the performance of the different devices with regards to their long term positional stability (migration).