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Sunday, November 15, 2026 · The Sunday letter

Histotripsy shrank month-old vein blockages by 59% in three pigs

A Chicago and Michigan team built scarred, collagen-heavy clots in pig leg veins, then broke them up with focused sound, in a six-animal pilot.

Illustration for: Histotripsy shrank month-old vein blockages by 59% in three pigs

The short version

  • Researchers grew clots in pigs’ leg veins for 30 days until they turned into tough, collagen-rich blockages like the ones that are hard to treat in people.
  • Histotripsy, which uses short bursts of focused ultrasound to break up tissue, reduced the blocked area by an average of 59% in the three pigs treated.
  • It is a six-animal pilot with no control group and no safety data in the published summary, so it shows the idea can work in principle and nothing more yet.

A blood clot in a leg vein that is not cleared can harden over weeks into a scarred plug that blood thinners and catheters struggle to remove. A team from the University of Chicago, the University of Michigan, the Medical College of Wisconsin and IIT Gandhinagar reports in Scientific Reports on November 7 that histotripsy, focused ultrasound that breaks tissue apart with bursts of tiny bubbles, can wear these plugs down in pigs.

The researchers formed clots in the femoral vein of six pigs and left them for 30 days. By then the blockages were mostly collagen, about 40% by area, with activated immune cells and fibroblasts, more scar-like than clots taken from patients a few weeks after onset. Three pigs were used to study that tissue. In the other three, histotripsy cut the blocked area seen on ultrasound by an average of 59%. The newest, still-remodeling tissue took the most damage.

The authors call it a pilot and a proof of concept. There was no untreated comparison group, the summary gives no spread around the average and no safety results, and two authors hold roles at a device company. It extends the work behind histotripsy’s approved use in liver tumors to a different target.

Audient reports on research and practice; it is not medical advice. Sound-based practices are generally low-risk, but people with epilepsy, implanted devices, hearing conditions or a history of trauma should check with a clinician first.

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