In the last few years there has been a revolution in the treatment of ischemic stroke. Thrombus dissolving drugs help many patients but have limited effectiveness when the large cerebral arteries are blocked. It has recently been shown that physically removing the thrombus through a catheter is remarkably effective atreducing the damage to the brain. Removing the thrombus can be effective up to 24 hours after the onset ofsymptoms.The retrieval method that is most consistently effective is to engage the thrombus with a stent-like retrieverand use the retriever to pull the thrombus back into a catheter. One of the challenging aspects of removing thethrombus with this method is that the thrombus cannot be directly visualized during the process of retrieval. Thethrombus can be left behind as the stent is pulled back, or fragments of the thrombus can break off and lodgedownstream where they cannot be reached. The thrombus itself cannot be seen in x-ray images so there is noway to know how completely the thrombus is being moved with the stent-retriever. We propose to develop unique magnetic nanotechnology to monitor mechanical extraction of thesethromboses. The thrombus will be coated with magnetic nanoparticles and the signal from those nanoparticleswill be used to monitor the position of the thrombus relative to the stent-retriever. Using the stent-retriever itselfas an antenna, one can measure signal from nearby magnetic nanoparticles bound within the thrombus. We willdemonstrate that the signal changes dramatically if the thrombus moves relative to the stent-retriever or if afragment breaks off the thrombus. We will also demonstrate that it is possible to produce images of the thrombusduring thrombus removal. These tools will enable the physician to reduce procedure time, more consistentlyremove the entire thrombus which we expect will improve patient outcomes.
Public Health Relevance Statement: Narrative:
We propose to develop unique magnetic nanotechnology to monitor mechanical extraction of thromboses
during the treatment of stroke. The thrombus will be coated with magnetic nanoparticles and the signal from
those nanoparticles will be used to monitor the position of the thrombus relative to the stent and to image the
thrombus. The tool we develop will enable physicians to remove thromboses more rapidly and completely,
addressing one of the key limitations that currently exists for this therapy.
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