Project Summary/Abstract The primary goal of this research project is to develop and pre-clinically validate a novel electrohydraulic impact (EHI) device that will aid clinicians in treating patients with peripheral artery chronic total occlusions (CTOs). CTOs represent the complete blockage of the blood vessels and are difficult to recanalize using traditional percutaneous transluminal angioplasty (PTA) techniques and apparatus. The presence of calcifications and fibrotic tissues within CTOs, together with the vessel size and tortuosity, are the causes of multiple complications during treatment. Therefore, a significant number of CTOs are treated using an invasive bypass surgery, which has significant morbidity and requires extensive recovery time. The central challenge to catheter based nonsurgical percutaneous CTO treatment is that it often is incredibly difficult to cross the calcified and resistant chronic blockage with an angioplasty wire. Although efforts have been made to use excimer lasers or rotational atherectomy devices (rotablator), these plaque modification devices require a wire to cross the CTO, which limits their utility if no wire crossing is established. To address this clinically important problem of difficult CTO crossing, Physical Sciences Inc. (PSI) in collaboration with Brigham and Women's Hospital (BWH) and Impact Vascular (IVAS) proposes to develop and pre-clinically evaluate a novel and safer method and device for CTO management. The proposed device uses an electrohydraulic impactor that creates a directed impact pressure of several hundred bar to penetrate the CTO plaque without damaging normal elastic arterial tissue. Therefore, EHI will facilitate CTO crossing and distal guide-wire passage to enable definitive treatment with balloons and stents.