Dr. Dai Yamanouchi, professor in the Division of Vascular Surgery, recently received a patent for a shear-thinning gel that can be used in combination with a previously patented delivery device to treat abdominal aortic aneurysms (AAA).
An AAA is the weakening and bulging of the lower part of the aorta where it passes through the abdomen. If the aneurysm ruptures, it can cause heavy bleeding, which could be fatal. To prevent a rupture, surgeons can either perform an open surgery or an endovascular surgery, which is a minimally invasive procedure that uses X-ray guidance and thin, flexible tubes called catheters to navigate to the aneurysm and place a stent graft. This redirects blood so it instead flows through the stent graft, taking the pressure off of the weak, bulging artery wall.
Endovascular surgery is the most common and preferred treatment for AAA because it is less invasive, results in a shorter hospital stay, and has a lower short-term recovery risk than open surgery, especially for older patients and patients that are high risk for complications. However, one downside of the procedure is that even when a stent graft is placed, the aneurysm is still there. In some patients, the small branches of blood vessels that are connected to the aneurysm can continue to place pressure on the aneurysm, causing the AAA to grow.
To combat the risk of continued growth, Dr. Yamanouchi and Dr. Shaoqin Gong from the UW Department of Biomedical Engineering developed a sheer-thinning gel that is designed to allow vascular surgeons to fill and close off the aneurysm sac after they have placed the stent graft. The properties of the gel allow it to be injected through a catheter into the aneurysm but prevent it from being dispersed into the smaller branches of blood vessels connected to the aneurysm. This additional step in the endovascular repair is designed to reduce persistent pressurization of the aneurysm sac and potentially prevent continued aneurysm growth.
Dr. Yamanouchi’s new patent, when paired with his previously patented delivery system device, could potentially provide a new treatment option for patients with AAAs in the future.
“This patent represents another step toward addressing one of the remaining limitations of endovascular aneurysm repair (EVAR),” Dr. Yamanouchi said. “Our goal is to develop a simple adjunct to EVAR that can help eliminate persistent blood flow and pressure within the aneurysm sac and ultimately improve the durability of treatment for patients.”
Dr. Yamanouchi worked with the Wisconsin Alumni Research Foundation (WARF) to file a patent for this injectable gel. WARF is the designated patenting and licensing organization for the UW-Madison, helping researchers bring transformative discoveries to the commercial marketplace.