Patent ID: 6893421

Claim:
A catheter shaft assembly, comprising: a first elongate shaft having an inner surface defining a lumen; a second elongate shaft having an outer surface, the second elongate shaft slidingly disposed within the lumen of the first elongate shaft; an interstitial member disposed between the inner surface of the first elongate shaft and the outer surface of the second elongate shaft, the interstitial member having a proximal end, a distal end, an inner surface, and an outer surface, the inner surface of the interstitial member facing a portion of the outer surface of the second elongate shaft between the proximal and distal ends of the interstitial member, and the inner surface of the interstitial member shaped to engage only a portion of the portion of the outer surface of the second elongate shaft between the proximal and distal ends of the interstitial member; a housing disposed about the first elongate shaft proximate the proximal end thereof; a slider disposed about the second elongate shaft proximate a proximal portion thereof wherein the slider is disposed within a chamber defined by the housing; a plurality of indicia disposed upon a surface of the housing proximate the slider; the second elongate shaft forming a point at the distal end thereof; the second elongate shaft defining an injection port proximate the point thereof; and the second elongate shaft defining an injection lumen in fluid communication with the injection port.