This SBIR Phase II project aims to continue the development of novel endografts for percutaneous treatment of abdominal aortic aneurysms (AAA) using unique and proprietary shape memory polymer (SMP) technology. Abdominal aortic aneurysms are both common and lethal in the older population, affecting between 7 and 13 % of older persons (> 60 years), accounting for between 13,000 and 18,000 deaths per year in the US alone, and increasing in diagnostic prevalence as both diagnostic techniques improve and the population ages. Endovascular treatment using covered stainless steel or Nitinol stent-grafts is now the preferred option for AAA treatment. However, current devices are far from perfect, and complications from endovascular repair such as endoleaks, continued growth of the aneurysm, device migration, arterial dissections, and other problems persist at very high (> 25-35%) rates. Most if not all these problems can be traced to the inherent limitations of the materials used in current devices. We propose to continue the highly promising Phase I work with particular focus on four areas: finalize polymer formulation; develop methods to manufacture patient-specific endograft designs; finalize biocompatibility evaluation; and evaluate endografts in acute and chronic animal studies. Anticipated deliverables at the end of the Phase II project are a finalized polymer formulation particularly suitable for endografts, complete ISO 109993 biocompatibility evaluation, methods to manufacture patient-specific endografts, and comprehensive data on the acute and chronic vascular response of the shape memory polymer endografts.
The broader impacts of this work lie in the development of the next generation of medical devices using advanced materials with characteristics that can be customized to the patient. The successful development of useful devices from such technologies should pave the way for a plethora of commercial opportunities including tissue-engineering applications whereby the "seeds' of new tissues or organs can be incorporated into shape memory polymer devices and delivered using minimally invasive methods into the target site to eventually grow healthy tissue. The ability to fuse shape memory polymer technology with advanced three-dimensional imaging and automated manufacturing methods, such as rapid prototyping and stereo-lithography, promises to open up the exciting prospect of creating patient-specific devices within the operating suite; devices that once manufactured can be compacted in situ into a catheter and delivered immediately into the patient. Lastly, successful completion of the overall project should have immediate impact on a disease that is the 13th leading cause of death in the US, and consequently on human health.
EndoShape, Inc. is developing an all polymer vascular stent for endograft treatment of Abdominal Aortic Aneurysms, a potentially life threatening condition. Its development is based on the superior characteristics of ESI’s proprietary shape memory polymer materials. Shape memory polymers are commonly referred to as "smart materials" as they change shape in response to a temperature change. EndoShape is addressing this market with a device superior to current products that use a metal frame and polymer cover, which can cause the delivery size of the device to be large and exposes the patient to the risk of fracture from repeated flexing over time. An endograft is placed inside a diseased blood vessel that contains a weakening in the vascular wall, an aneurysm. The placement process is minimally-invasive, involving catheters to deliver the device. The typical metal and polymer fabric devices available today present significant limitations, which reduces the number of patients eligible for this procedure. As such, many current patients require a more complex surgical procedure for aneurysm repair. Through this SBIR grant, EndoShape has pursued improved material capabilities of a shape memory polymer for advanced medical device applications. This resulting novel material offers radiopacity, biodurability, and material properties necessary to enable a vascular stent. Through various testing procedures, our research and development efforts in polymer chemistry and device design have demonstrated the feasibility of a shape memory polymer endograft and frame. This basic work should pave the way for a plethora of commercial opportunities, and is expected to find wide application in the development of new medical devices to address important, unmet clinical needs.
