A new, very effective drug combination device for the treatment of life-threatening blood clots in stroke patients has been developed by a team of researchers at the Harvard Wyss Institute and Massachusetts University. The study, published in the Stroke Review, describes a new method for rapidly disrupting clots that completely block blood vessels in the brain.
The new method combines an injectable thrombolytic nanotherapeutic that targets blockages with an intra-arterial device that restores blood flow to blocked vessels.
The Wyss Institute has already discovered new Nanotherapeutics consisting of a set of biodegradable nanoparticles coated with a thrombolytic drug called tissue plasminogen activator (tPA), which mimics the way platelets behave in our own organs.
When the blood vessels narrow, the shear force of the blood flow at this site increases, producing a natural order causing the platelets to stick to the vessel wall. The nanotherapeutic reacts to the shear force of the fluid, releasing coated nanoparticles in these areas, where the vessels are blocked where it adheres to the blood clot by dissolving it.
But to date, mechanically activated nanotherapeutic is not effective in full vascular obstructions where there is no blood flow, as is the case for most stroke patients. The most effective treatment for the stroke today is known as the stent-retriever thrombectomy procedure. The procedure involves placing a small tube through the occlusion, passing a stent inside it, and then opening the stent to remove the blood clot from the vessel.
Instead, the new method describes the use of the stent, not to remove the thrombus, but to create a narrow channel that restores the flow of blood through an opening at the center of the vascular occlusion. This creates a high level of shear force produced by the restoration of the flow, activating the nanotherapeutic, releasing the thrombolytic drug along the channel where the thrombus is present. After complete thrombus dissolution, the stent is safely removed from the vessel.
In clinical studies of large animals, the research team demonstrated that the drug-device combination works very effectively, indicating that it dissolves blood clots that completely block blood vessels of the brain that are the same size as they would be in humans.