Grant: Project Grant

The blockage of flow in large blood vessels by blood clots is a major cause of death and disability in conditions such as strokes, heart attacks and pulmonary embolisms. In many cases, medicine is given via the bloodstream to dissolve the clots. Unfortunately, this is not possible to do in many patients because there is a risk of serious side effects, and when given they are often not effective. To address these issues, catheter-based approaches have been developed to 'mechanically' extract the clots. A common way of doing this is to use suction ('aspiration'). This involves the doctor inserting a catheter - basically a specialized hollow tube- into a blood vessel and positioning its tip next to the clot, which is then sucked into the catheter and blood flow returns to normal. While this method is widely used, in many cases the clot is too stiff and while part of it can enter the catheter tip, the suction is not strong enough to fully extract it. The goal of this project is to develop a new type of aspiration catheter, one where ultrasound can be applied at the tip to break up the clot as it enters so that they do not simply clog up the tip. The key to this is to use a hollow cylinder-shaped transducer (part that generates ultrasound) that creates extremely high-power ultrasound within the tip that causes bubbles to form and vibrate violently to break up the clots. In our work to date, we have shown that this type of transducer can achieve this. In this research, we will design, fabricate and test a prototype catheter version with this approach. This will be done first with a combination of computer simulations and device construction, followed by testing and optimizing using a combination of bench-top clot experiments followed by animal experiments. The result of this research will be the development of a new class of aspiration catheters with improved performance on challenging clots that has the potential to impact the treatment of a wide range of patients.