Everting filter devices and methods for using the devices, including using
the devices as intra-vascular filters to filter thrombus, emboli, and
plaque fragments from blood vessels. The filter devices include a filter
body nominally tubular in shape and having a large proximal opening. The
filter body can extend from a proximal first end region distally over the
non-everted exterior surface of the filter, further extending distally to
a distal-most region, then converging inwardly and extending proximally
toward the filter second end region, forming a distal everted cavity. The
degree of eversion of the filter can be controlled by varying the
distance between the filter first end region near the proximal opening
and the closed second end region. Bringing the filter first and second
end regions closer together can bring filter material previously on the
non-everted filter exterior to occupy the distal-most region. The
everting process can also bring filter material previously in the
distal-most position further into the distal everted cavity. The filter
devices can be used to remove filtrate from body vessels, with the
filtrate eventually occluding the distal-most region. The filter can then
be further everted, bringing fresh, unoccluded filter material into place
to provide additional filter capacity. Some everting filters have the
capability of switching between occluding and filtering modes of
operation, thereby allowing a treating physician to postpone the decision
to use filtering or occluding devices until well after insertion of the
device into the patient's body.