Catheter having an auxiliary lumen for use with a functional measurement wire

1. Apparatus for facilitating the advancement of a functional measurement wire to a vascular treatment site, the apparatus comprising:

an outer tube having proximal and distal ends;

an inner tube having proximal and distal ends and a working lumen extending therethrough, the inner tube being disposed within the outer tube;

an auxiliary tube having proximal and distal ends and an auxiliary lumen extending therethrough, wherein the auxiliary lumen communicates at the proximal end with a side port disposed in a lateral surface of the outer tube and at a distal end communicates with the working lumen of the inner tube to define a bifurcation; and

a stylet having proximal and distal ends, and a receptor coupled to the distal end, the receptor adapted to engage a proximal end of a functional measurement wire, the stylet slidably and removably disposed within the auxiliary lumen,

wherein the auxiliary lumen and the stylet are configured to permit the functional measurement wire to be backloaded through a distal end of the working lumen to engage the receptor when the receptor is advanced into the bifurcation.

2. The apparatus of claim 1 wherein a space between the inner tube and the outer tube forms an inflation lumen.

3. The apparatus of claim 2 further comprising a balloon affixed at a proximal point to the distal end of the outer tube and further affixed at a distal point to the distal end of the inner tube, wherein the balloon is in fluid communication with the inflation lumen.

4. The apparatus of claim 1 wherein the distal portion of the working lumen is configured to permit the longitudinal advancement of a guidewire.

5. The apparatus of claim 1 wherein the distal portion of the working lumen is configured to permit the longitudinal advancement of the functional measurement wire.

6. The apparatus of claim 1 further comprising a taper that provides a transition between the inner tube and the auxiliary tube, the taper configured to facilitate the distal advancement of the functional measurement wire from the auxiliary lumen into the distal portion of the working lumen.

7. The apparatus of claim 1 further comprising a circumferential taper disposed just distal to the bifurcation, the circumferential taper configured to facilitate the distal advancement of the functional measurement wire from the auxiliary lumen into the distal portion of the working lumen.

8. The apparatus of claim 1 further comprising a functional measurement wire adapted to provide pressure or flow measurements.

9. A method for facilitating the advancement of a functional measurement wire to a vascular treatment site, the method comprising:

providing apparatus comprising an outer tube having proximal and distal ends, an inner tube having proximal and distal ends and a working lumen extending therethrough, wherein the inner tube is disposed within the outer tube, and an auxiliary tube having proximal and distal ends and an auxiliary lumen extending therethrough, wherein the auxiliary lumen communicates at a proximal end with a side port disposed in a lateral surface of the outer tube and at a distal end communicates with the working lumen of the inner tube to define a bifurcation, and a stylet having proximal and distal ends, and a receptor coupled to the distal end of the stylet, wherein the receptor is adapted to engage a proximal end of a functional measurement wire backloaded through a distal end of the working lumen;

advancing the stylet so that the receptor is positioned within the bifurcation;

backloading a functional measurement wire through the working lumen so that a proximal end of the functional measurement wire engages the receptor;

withdrawing the stylet proximally until the proximal end of the functional measurement wire exits the side port; and

disengaging the proximal end of the functional measurement wire from the receptor

positioning a functional measurement wire within the auxiliary lumen;

advancing the apparatus to a treatment site over a guidewire disposed within the working lumen;

retracting the guidewire within the working lumen to a location proximal of the bifurcation; and

selectively advancing the functional measurement wire into the working lumen to obtain measurements near the treatment site.

10. The method of claim 9 wherein positioning the functional measurement wire within the auxiliary lumen further comprises:

advancing a distal end of the functional measurement wire into the auxiliary lumen via the side port; and

distally advancing the distal end of the functional measurement wire within the auxiliary lumen.

11. The method of claim 9 wherein obtaining measurements near the treatment site includes obtaining pressure measurements.