In one embodiment of the present invention there is provided a method of positioning a filter within a lumen by positioning a filter within a lumen by exerting a radial force generated by a support structure against the lumen while suspending a material capture structure between opposing members of the support structure; and self adjusting the length of the filter support structure along the lumen wall in response to a change in the size of the lumen. In another embodiment of the present invention there is provided a method of providing protection during a procedure performed in the vasculature by placing an open loop device within a vessel down stream of a location in the vasculature; performing a procedure to treat the vasculature in proximity to the location; and capturing debris released during the procedure in a material capture structure suspended across the vessel and supported by the open loop device.