Some ischemic strokes are now successfully treated using intravascular clot retrieval devices, but in many instances this option is not advised. Moreover, the retriever can dislodge bits of the clot that end up embolizing deeper into the brain. Clot busting drugs, on the other hand, can’t get into a complete occlusion since there’s no blood flow. A team from Harvard’s Wyss Institute and University of Massachusetts’ New England Center for Stroke Research have developed a new approach that combines a device that creates a tunnel through the clot with pressure activated nanoparticles that release clot busting drugs when passing through the narrow channel.
The particles mimic how platelets stick to vessel walls where blood undergoes high pressures. Tissue plasminogen activator (tPA) coated over the nanoparticles release when the particles stick to the clot, dissolving it quickly at the point of occlusion. Any dislodged bits of the clot should also get a nanoparticle or two stuck to them. So as they travel down the vasculature they continue to be dissolved to prevent further harm. The stent that’s driven through the initial clot remains in place during the introduction of the nanoparticles and is retrieved at the end of the procedure.