High-intensity focused US: A potential new treatment for GI bleeding

Background: High-intensity focused US has been shown to achieve hemostasis in lacerated large veins and arteries. High-intensity focused US was studied as a potential endoscopic treatment for GI bleeding. Methods: A segment of the auricular vein of the rabbit was lacerated longitudinally and then treated with a high-intensity focused US transducer driven at 3.9 MHz (focal intensity of 750 W/cm²) in 15 animals until hemostasis was achieved. Sham treatment was delivered to 3 vessels. Rabbits were euthanized on days 0, 2, 7, 14, and 28 to allow for histologic evaluation of the response to treatment. Results: Hemostasis was achieved in all treated vessels and in none of the sham treatments. Mean treatment time was 13 seconds. Histology initially demonstrated acute thermal injury with subsequent thrombus formation and chronic inflammation leading to replacement of the vessel by fibrous scar tissue. Conclusions: High-intensity focused US causes hemostasis in acutely bleeding veins and results in occlusion of treated vessel with subsequent granulation tissue formation.