Appeal No. 2002-1671 Page 11
Application No. 08/993,985
Chaikof's invention relates to intraluminal prosthetic devices. In particular,
Chaikof's invention relates to self-expanding intraluminal composite prosthetic devices
for use, e.g., in endovascular applications. Chaikof teaches (column 5, lines 20-57) that
[t]he present invention provides a true composite device that possesses
the structural and mechanical reinforcing characteristics of a stent with the
containment characteristics of a graft. A "composite" as used herein refers to two
components, e.g., the reinforcing and sealing components that are blended
rather than two devices that are attached. Blending of components can be
achieved by any of a number of means including, but not limited to, interweaving
the component fibers to form a composite structure.
The device of the present invention consists of a mechanically stiff
component that is blended with a more compliant component, the combination of
which is fabricated as a straight or branched tubular structure. The stiff
component provides mechanical resistance such that any radial deformation of
the tube requires some force. Further, the elastic deformation characteristics of
the two components can be identical such that deformation of the device (for
delivery or deployment) occurs in an isotropic fashion so as to avoid internal
stress gradients that may cause the two components to separate. The composite
nature of the device homogeneously distributes these forces so as to minimize
the possibility of device failure. This is in contrast to the assembly of two
separate devices (such as a graft and a stent) where the stress is concentrated
in whatever means is used to fasten the two devices together. The isotropic
expansion characteristics possessed by the present invention also minimize the
damage to vascular tissue that potentially occurs with other devices such as a
Nitinol stent.
Although braiding of the components comprises the preferred
embodiment of the device, blending of any two components that possesses
these consistent deformation characteristics may be used. Other possible
composite systems include an expanding metal mesh protruded in a tubular form
with a polymeric matrix that is subsequently cross-linked, by chemical, radiative
or other means to form an elastomeric matrix with deformation characteristics
consistent with those of the metal mesh.
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