Configuration and method for fixation of a filter to a catheter
An attachment configuration for a vascular filter assembly including a self-expanding filter member attached to a catheter body and constrained from expansion in a first configuration by a constraining sheath is presented. The attachment configuration includes an outer tube of material that is overlaid over an end of the filter member and bonded to the catheter body through cutouts disposed through the end of the filter member.
1. A method for attaching a proximal end of a filter member, comprising:
a. disposing a thin tube over a catheter body and over at least a portion of the proximal end of the filter member, wherein the proximal end of the filter member includes a first row of a repeating pattern of a plurality of first cutouts along a longitudinal axis of the proximal end of the filter member and a second row of a repeating pattern of a plurality of second cutouts along the longitudinal axis of the proximal end of the filter member, the first cutouts comprising semi-circular shape cutouts having a first leg and a second leg encircling the semi-circular cutout; the second cutouts comprising diamond-shaped cutouts, whereby the diamond-shaped cutouts are each bounded by strut members forming a first half and a second half of each of the diamond-shaped cutouts; and the first half and the second half of each of the diamond-shaped cutouts are each attached to the first legs of the semi-circular cutouts;
b. disposing a heat shrink tube coaxially over the thin tube; and
c. fusing the thin tube to the catheter body through the plurality of cutouts to attached the proximal end of the filter member to the catheter body.
2. The method of claim 1 , wherein the fusing step is heating.
3. The method of claim 2 , further comprising inserting polymer coated metal wires into the lumen of the catheter body.
4. The method of claim 3 , wherein the thin tube and the catheter body are made of a same material.
5. The method of claim 4 , further comprising removing the heat shrink tube from the thin tube.
6. The method of claim 5 , further comprising using a heat shield to protect at least a portion of the proximal end of the filter member from fusing to the catheter body.
7. The method of claim 6 , wherein the polymer coated metal wires include a different material from the thin tube.
8. The method of claim 1 , wherein each of the second cutouts includes a width W extending generally along the longitudinal axis of the proximal end and a height H extending generally along the longitudinal axis of the proximal end, wherein the width W is greater than the height H.
9. The method of claim 1 , wherein each of the diamond-shaped cutouts further have a first end and a second end, each of the first end and the second end project into a portion of the semi-circular cutouts, and the first end and the second end of longitudinally adjacent diamond-shaped cutouts have a space therebetween.
10. The method of claim 9 , wherein a distal end of the thin tube is positioned at the space between the first end and the second end of the diamond shaped cutouts.
11. The method of claim 9 , wherein the proximal end of the filter member is radially expandable.