PROJECT SUMMARY This SBIR Phase I project will focus on the development of a catheter specifically designed to reduce bleeding complications from catheter-directed thrombolysis (CDT) treatment of pulmonary embolism (PE). PE represents a leading cause of morbidity in the United States, with as many as 900,000 cases per year in the United States alone. One in four patients with PE will die suddenly without warning, and PE is the third most common cause of cardiovascular death. In addition, blood clots represent a significant burden on the economy, with healthcare costs accounting for up to $10 billion dollars annually. CDT involves placing one or more small catheters directly within the blood clot(s) in the lung(s) and infusing a thrombolytic medication (e.g. tissue plasminogen activator) to dissolve the clots over a 2-24 hour time period. It is preferred over a peripheral intravenous bolus administration of tPA in all but the highest risk patients, as a slower, more controlled infusion correlates with lower rates of life-threatening bleeding. While CDT-based thrombolytic infusions can be immensely effective, this therapy carries the risk of major adverse events including catastrophic intracranial, vascular, or intra-abdominal bleeding, and the risk of bleeding complications is proportional to the dose and duration of thrombolytic infusion. To minimize this risk, the lowest possible dose of thrombolytic should be infused over the shortest duration. This ideal endpoint would be the point when complete lysis occurs and any added thrombolytic only increases risk without any therapeutic benefit. To date, no existing CDT device allows for personalized treatment and real time monitoring of lytic effectiveness to allow for judicious titration of thrombolytic administration. Customer discovery revealed that providers desire pressure data to inform treatment decision-making. The proposed device is a CDT catheter which minimizes the dose of thrombolytic delivered. It does this by enabling hemodynamic monitoring across a thrombus for real-time detection of thrombus disruption, AND by deploying expanding nitinol lytic “baskets” for maximized thrombolytic contact area with thrombi. Its all-in-one design makes the procedure easier, safer, and less costly for the hospital. This catheter comprises two telescoping catheters wherein the outer catheter can be translated to selectively expose preformed nitinol tubing baskets for adjustable-length three-dimensional lytic infusion. The combined catheter system has four ports, each designed to address CDT milestones. The device will allow the user to (1) precisely steer the catheter and sub-select a target branch, (2) perform high pressure contrast injections to obtain diagnostic-quality angiograms, (3) infuse lytic in the full three-dimensional space of the vessel to precisely fit and fully saturate the thrombus, and (4) measure real-time, continuous, simultaneous, fluid-filled pressure proximal and distal to a thr...