ArchGuard

What it does

Patients are susceptible to strokes as dislodged debris travels to the brain during interventional cardiology procedures. ArchGuard uniquely offers complete cerebral protection using a shape-memory frame and porous mesh to deflect debris away from the brain.

Your inspiration

Following the Stanford Biodesign process for insight-informed innovation, our team observed several interventional cardiology procedures and interviewed leading key opinion leaders in interventional cardiology across the United States to uncover a debilitating and unmet clinical need: physicians need a safer and more intuitive way to prevent strokes and silent ischemia during transcatheter aortic valve replacement (TAVR) procedures. A thorough literature search confirmed the urgency and necessity for a solution to this need: 2.8% of patients who undergo a TAVR procedure develop strokes, while 80% have signs of silent ischemia.

How it works

ArchGuard is a temporarily implanted device. It utilizes a porous nylon mesh that permits ample blood flow to the brain, but prevents dislodged debris from passing through during interventional cardiology procedures. The mesh is held open by a shape-memory NiTinol (nickel-titanium) frame to securely fit in a variety of anatomies. ArchGuard is deployed via a catheter from an artery in the patient’s wrist and advanced under x-ray guidance to the patient’s aortic arch. The device is advanced out of its catheter and deployed using a stiff tether and securely remains in place during the entire procedure. ArchGuard functions as a complete deflector, meaning it shields all three arteries supplying blood to the brain by safely directing dislodged debris away from the brain. Lastly, the device provides minimal interruption to other instruments that traverse the patient’s aortic arch during these procedures, thus allowing for easy integration into current workflows.

Design process

Our team began the design process by defining user requirements after observing interventional cardiology procedures and holding interviews with key opinion leaders (KOLs) spanning engineering and medicine, in addition to conducting a thorough patent and literature search to clearly identify our freedom to operate. These requirements set the foundation for the “must have” and “nice to have” features for the invention and were added to the design history file (DHF). With a complete set of user requirements, our team laid out quantitative design requirements to add to the DHF, followed by two months of brainstorming 20 initial concepts. We had each KOL rank these concepts according to 12 criteria. Since the top three concepts were of nearly equal rank, we created an initial “hybrid” prototype to share with the KOLs. Next, we created 3D-printed benchtop testing fixtures to test the initial prototype against performance criteria. Over the course of three months, 11 different iterations were created addressing realizations found during design verification and mechanical testing. Most recently, we collaborated with a contract manufacturer to create high-fidelity prototypes to refine the retraction and deployment mechanisms of the device in a simulated benchtop model.

How it is different

Our invention is protected by a provisional patent and is currently under review by the USPTO for conversion to a full utility patent. The invention includes two novel components to maximize its safety and efficacy: 1) its NiTinol (nickel-titanium) frame and nylon mesh design and 2) its additional alignment flexibility feature. ArchGuard’s NiTinol frame is composed of two loops connected by a single wire. To our knowledge, there are no existing devices or intellectual property associated with such a design. Unlike existing cerebral protection devices, our invention remains secured in the patient’s aortic arch without having to rely on alternative anchoring mechanisms or placement inside more delicate arteries, as is done with existing devices. In addition, our invention offers an additional 50% alignment flexibility by having a rotationally-symmetric frame and mesh design, while existing products lack such flexibility.

Future plans

Our next step is to incorporate feedback from key opinion leaders into our current prototype iteration. Next, we’ll conduct more verification and validation benchtop testing to ensure our design satisfies criteria in our design history file. Once we finalize the design and manufacturing/assembly instructions, we’ll work with a medical-grade manufacturer to produce pre-clinical prototypes to be used in usability and animal testing. We’ll use data from these tests in our application to the FDA to obtain approval for selling our device. Our long-term goal is global adoption in interventional cardiology procedures to improve patient outcomes.

Awards

ArchGuard won the $100k Texas Medical Center Innovation prize at the 2021 Rice University Business Plan Competition, 2nd Place at the 2020 Johns Hopkins Healthcare Design Competition, and Duke University grants. The invention was converted from a provisional patent to full utility patent application with the USPTO in 2021.