When trying to remove life-threatening clots from blood vessels, current technologies are successful on only about half of the first attempts – if at all. A new surgical tool, however, is claimed to boost that figure to an astounding 90%.
Although blood clots are partially made up of red blood cells, they're held together by tangles of a thread-like protein known as fibrin. Existing clot-removal treatments typically involve inserting a device into the affected blood vessel via a catheter, then using that device to either suck up the fibrin clump or snare it then drag it out.
Whichever the case, the fibrin often gets inadvertently broken up in the process, with some of the pieces proceeding to travel down the blood vessel. Those fragments could ultimately form into new blood clots, in locations that are more difficult to reach.
That's where the milli-spinner comes in.
Developed by Asst. Prof. Renee Zhao, Assoc. Prof. Jeremy Heit and colleagues at Stanford University, the catheter-delivered device takes the form of a rapidly rotating tube with a series of fins and slits at the tip. As that tip spins near the clot, it creates both compressive and shear forces.
The compressive force presses the fibrin threads together as they're sucked up against the open end of the tube, while the shear force rolls them up into a small, tight, fully intact ball. That ball is then easily and completely removed via suction. The freed-up red blood cells get carried away by the bloodstream.
In blood-vessel-model and live pig tests, the milli-spinner was able to reduce the volume of clots by up to 95%, allowing for successful clot removal on approximately 90% of first attempts. This would constitute a huge life-saving difference when treating clot-related conditions such as stroke and heart attack.
"It works so well, for a wide range of clot compositions and sizes," says Zhao. "Even for tough, fibrin-rich clots, which are impossible to treat with current technologies, our milli-spinner can treat them using this simple yet powerful mechanics concept to densify the fibrin network and shrink the clot."
The scientists have now started a spinoff company to commercialize the technology, which they believe could be adapted to treat other conditions such as kidney stones.
A paper on the research was recently published in the journal Nature.
Source: Stanford University