SBIR Phase I: A Mechanical Blood Clot Removal Device for Pulmonary Embolism

The broader impact/commercial potential of this Small Business Innovation Research (SBIR) Phase I project is in addressing blood clots in the pulmonary artery. Venous thrombosis, comprising deep vein thrombosis (DVT) and pulmonary embolism (PE), occurs with an incidence of approximately 1 per 1000 annually in adult populations. Estimates suggest that 60k -100k Americans die of DVT/PE (also called venous thromboembolism). The current treatments are high risk to the patients and very expensive to the health care systems. Current treatment methods involve the use of systemic or catheter-directed thrombolytic medications to break down the clot and restore blood flow. The use of these medications carries the risk of bleeding in different parts of the body which can lead to death. Open-heart surgery is another treatment method, but the high risk of this critical surgery requires highly skilled physicians and advanced equipment that may not be available in most hospitals. The proposed device is simple and intuitive and allows the physicians to complete the treatment and restore the blood flow in less than 30 minutes of the patient arrival while other treatment methods take several hours for mechanical thrombectomy and several days for catheter-delivered thrombolysis. This will significantly reduce the total procedure cost by reducing the length of stay in the intensive care unit from the average of 2-3 days to only a few hours. The proposed project advances the current of the art of Nitinol medical device design, fabrication, and evaluation. The proposed clot removal device targets pulmonary embolism which is a common disease and may lead to death. The proposing team has established the technologies and know-how to produce the core Nitinol components of device. These include a simulation-based design optimization methodology, which has been used for the design of the main blood clot capturing funnels from Nitinol. The team has established innovative non-conventional fabrication and post-processing heat treatment procedures. Based on the anatomy and functionality of the circulation system an innovative test set up has been fabricated that can replicate the blockage of arteries. To this end, human blood clots are created and inserted in the test apparatus for a later retrieval. One of the main innovations is a Nitinol structure designed to allow for a 7-fold increase in the diameter of the blood capturing device when deployed: when deployed these Nitinol elements can expand from 2mm to 14mm in diameter, without any balloon or other external force. This innovative functionality has never been achieved before and is essential for the atraumatic functionality of the proposed device. This has been achieved by developing a mathematical method to systematically calculate the shape and size of laser cutting feature on a tube of Nitinol. With proper heat treatment, this tube can be formed to produce the two capturing baskets. The team has also used additive manufacturing and advanced computer simulation to create a test setup for in vitro testing of the capturing device.