Small blood clots called emboli are mostly known for traveling through the vasculature before they lodge and obstruct vessels, impeding blood and oxygen supply to organs such as the lung. To stop excessive bleeding or the flow of blood into an aneurysm, clinicians harness the same principle by forming artificial therapeutic emboli that can plug blood-carrying vessels. Using steerable catheters, they place tiny soft-metal coils or liquid embolic agents (“glues”) into the affected artery to block the passage of blood.
However, both procedures come with problems and risks. Coil embolization can be ineffective if the coil is not positioned or seized accurately, and coils need efficient blood clotting in patients to be stabilized. Liquid embolic agents, on the other hand, can be accidentally cemented to catheters or non-targeted areas due to insufficient control of their solidification. And, importantly, both types of emboli can become leaky over time.
A team of researchers at Harvard’s Wyss Institute for Biologically Inspired Engineering, Brigham and Women’s Hospital, the Mayo Clinic, and MIT now describe a new class of hydrogel-based embolic agents that could help eliminate all these drawbacks. Their study, published in Science Translational Medicine, provides proof of concept and first preclinical evidence in animal models that the shear-controlled hydrogel can be delivered by catheters and injected into blood vessels to form robust and safe blockages.
“This new approach to vascular embolization is based on a hydrogel composite with phase properties we can reliably control with mechanical pressure. It completely blocks vessels in situations where other methods can fail, such as in vascular areas that are highly convoluted or subject to unusual blood pressures, and, importantly, it still works when normal blood coagulation is impaired, like in patients receiving blood thinners or suffering from an intrinsic inability to efficiently form blood clots,” said Ali Khademhosseini, an associate faculty member of the Wyss Institute, and a professor at Harvard-MIT’s Division of Health Sciences and Technology and Brigham and Women’s Hospital.