Honorable Mention: Intelligent AV Grafts for Predicting Stenosis and Avoiding Thromboses
Fistulas and grafts have extremely high rates of failure. When physicians connect an artery and a vein, the change in blood velocity creates eddy currents that can lead to thromboses. The problem is exaggerated in grafts, since the foreign body response tends to lead to graft stenosis, so that thromboses happen often. If there is a thrombosis, then blood backs up and dialysis is no longer effective. For patients that rely on dialysis for life, this can lead to buildup of toxins throughout the body and morbidities or even death if not caught. Even if caught in time, problems with graft stenosis can lead to loss of the graft and can require a new graft to be implanted, a process which takes many months and during which the patient must be placed on peritoneal catheter dialysis.
Modern grafts consist of a Teflon membrane and are not able to react or sense stenosis or thromboses. For most patients, a loss in graft patency is first noticed when the efficiency of dialysis, as measured by a bi-weekly blood test, begins to drop. Earlier symptoms can include pain and numbness in the hands, due to loss of blood flow, or excessive bleeding at the needle insertion site due to back pressure generated by the clot. Once a blockage is suspected, patients must undergo a fistulagram, where contrast agent is injected into the system and CT is used to directly image a blockage. Once the blockage is located, thrombectomy or thrombolysis is attempted; a catheter is inserted, and physical or local pharmaceutical methods are used to break up the clot. To open the stenotic graft, an angioplasty catheter is used to expand the graft and restore patency. However, oftentimes, the period of time between initial symptoms and fistulagram is so long that the graft (or fistula) is lost, and a new one must be surgically placed. During the 3-4 weeks recovery period, patients must then use a peritoneal catheter for their treatment.
At Senseer, we address this large unmet need by developing an intelligent graft that can report in real-time relevant hemodynamic measurements directly to a patient and physician. The graft would be embedded with polymer biosensors that can measure pressure, flow rate, graft patency, ionic concentration, and temperature within the graft. The data would be wirelessly transmitted out of the body and stored in a cloud-based database that could be accessed by both physicians and patients. Advanced analytics will be used to detect changes in patient status days or weeks before it would be possible with traditional metrics and before symptoms arise. This, on the other hand, would enable early intervention to maintain dialysis efficiency and prevent graft loss.
To learn more, please visit www.senseer.us.