As may be implemented with various aspects of the present disclosure, a mesh structure is coupled to inner and outer frames that operate with struts to apply pressure to the mesh. Such an approach may involve sealing the mesh around an opening, such as around one or more artery openings along an interior wall of vascular tissue (e.g., in an aortic arch). Accordingly, blood flow can be filtered in a manner that is useful for capturing particulates such as those resulting from surgical operations. In various implementations, the mesh, struts and frames are deployed using a catheter and shaft coupled to the frames. Such an approach can be implemented to apply a spring force from the shaft and through the frames for sealing the mesh.