LAUSR

The structural stability of medical devices is established by managing stress distribution in response to organ movement. Veins abruptly dilate upon arterial grafting due to the mismatched tissue property, resulting in flow disturbances and consequently stenosis. Vascular cast is designed to wrap the vein‐artery grafts, thereby adjusting the diameter and property mismatches by relying on the elastic fixity. Here, a small bridge connection in the cast structure serves as an essential element to prevent stress concentrations due to the improved elastic fixity. Consequently, the vein dilation is efficiently suppressed, healthy (laminar and helical) flow is induced effectively, and the heathy functions of vein grafting are promoted, as indicated by the flow directional alignment of endothelial cells with arterialization, muscle expansion, and improved contractility. Finally, collaborative effects of the bridge drastically suppress stenosis with patency improvement. As a key technical point, the advantages of the bridge addition are validated via the computational modeling of fluid–structure interaction, followed by a customized ex vivo set‐up and analyses. The calculated effects are verified using a series of cell, rat, and canine models towards translation. The bridge acted like “Little Dutch boy” who saved the big mass using one finger by supporting the cast function.