External Self‐Closing Tube to Occlude a Vessel Gradually as a Therapeutic Means of Portosystemic Shunt

Abstract The vascular network to the liver can be connected abnormally during fetal development (e.g., portosystemic shunt), thus requiring a device to close the flow connection completely. Gradual vascular occlusion is particularly important, because a sudden stop in blood flow can result in portal hypertension and cause consequential damage to the small intestine. Significant progress has been made in the development of such devices (e.g., the ameroid ring constrictor and cellophane banding) as a standard treatment for this disorder. However, incomplete occlusion is a common problem. In this study, a new vascular occlusion device is developed, enabling two major functions. First, user‐friendly deployment onto the external vascular wall is achieved by programming a recovery in the shape of the tube from open to closed in response to treatment with a warm saline solution (37 °C). Second, proinflammatory palmitic acid is released over time from the tube surface through the adventitial wall to induce gradual occlusive vascular remodeling. These unprecedented functions are demonstrated in a series of experiments on cells and rabbit veins, addressing this major issue through gradual but complete vascular occlusion over time. The external self‐closing tube represents a breakthrough proof‐of‐concept for treatment of this rare but critical developmental disorder.