Medical device including tube having a braid and an expanded coil
A medical device ( 10 ) including a tube ( 11 ) having a highly uniform and repeatable inner and outer diameter, the tube ( 11 ) possessing good trackability, pushability and torquability, and the tube ( 11 ) being highly resistant to collapse, necking or kinking during use. The tube ( 11 ) first includes a metal coil ( 14 ) in a stressed, radially expanded condition, the metal coil ( 14 ) preferably being formed as a flat wire. The tube ( 11 ) also includes a metal braid ( 16 ) extending over at least part of the coil ( 14 ). The tube ( 11 ) further includes a polymeric bonding layer ( 18 ) positioned over and contacting at least the coil ( 14 ). The polymeric layer ( 18 ) is preferably heat-shrinkable shrinkable tubing made of one or more of nylon or polyurethane. The tube ( 11 ) optionally includes an inner liner ( 20 ) beneath and in contact with at least part of the coil ( 14 ), the liner ( 20 ) preferably being composed of PTFE. The polymeric layer ( 18 ) maintains the coil ( 14 ) in its stressed, radially expanded condition, for example, by adhesion to the coil ( 14 ) (such as by thermal bonding to it).
1. A medical device ( 10 ) comprising a tube ( 11 ), wherein the tube ( 11 ) comprises:
a coil ( 14 ) in a stressed, radially expanded condition;
a braid ( 16 ) extending over at least part of the coil ( 14 ); and
a polymeric layer ( 18 ) positioned over and contacting at least the coil ( 14 );
the polymeric layer ( 18 ) maintaining the coil ( 14 ) in the stressed, radially expanded condition.
2. The medical device ( 10 ) according to claim 1 , wherein the polymeric layer ( 18 ) maintains the coil ( 14 ) in the stressed, radially expanded condition by adhesion to the coil ( 14 ).
3. The medical device ( 10 ) according to claim 1 , further comprising an inner liner ( 20 ) beneath and in contact with at least part of the coil ( 14 ).
4. The medical device ( 10 ) according to claim 1 , wherein at least one of the coil ( 14 ) and the braid ( 16 ) comprises a metal.
5. The medical device ( 10 ) according to claim 1 , wherein the braid ( 16 ) comprises a plurality of crossed wires ( 22 ).
6. The medical device ( 10 ) according to claim 5 , wherein the wires ( 22 ) are circular in cross-section.
7. The medical device ( 10 ) according to claim 1 , wherein the coil ( 14 ) comprises flat wire.
8. The medical device ( 10 ) according to claim 1 , wherein the polymeric layer ( 18 ) comprises at least one of nylon, polyurethane and PTFE.
9. The medical device ( 10 ) according to claim 8 , wherein the polymeric layer ( 18 ) is encased within an additional layer of heat-shrinkable tubing.
10. The medical device ( 10 ) according to claim 2 , wherein the polymeric layer ( 18 ) is thermally bonded to the coil ( 14 ).
11. The medical device ( 10 ) according to claim 3 , wherein the inner liner ( 20 ) comprise PTFE.
12. The medical device ( 10 ) according to claim 1 , wherein the tube ( 11 ) has an outer diameter no greater than about 2 mm.
13. The medical device ( 10 ) according to claim 1 , wherein the polymeric layer ( 18 ) comprises at least two discrete longitudinal segments ( 28 and 30 ) of differing durometer.
14. A medical device ( 10 ) comprising a tube ( 11 ), wherein the tube ( 11 ) comprises:
a metal coil ( 14 ) in a stressed, radially expanded condition, the metal coil ( 14 ) comprising flat wire:
a metal braid ( 16 ) extending over at least part of the coil ( 14 );
a substantially imperforate polymeric bonding layer ( 18 ) positioned over and contacting at least the coil ( 14 ), wherein the polymeric layer ( 18 ) is heat shrinkable tubing comprising at least one of nylon, polyurethane and PTFE; and
an inner liner ( 20 ) beneath and in contact with at least part of the coil ( 14 ), the liner ( 20 ) comprising PTFE;
wherein the polymeric layer ( 18 ) maintains the coil ( 14 ) in the stressed, radially expanded condition by adhesion to the coil ( 14 ) by thermal bonding to it; and
wherein the tube ( 11 ) has an outer diameter no greater than about 1 mm.