Patent ID: 8398579

Claim:
A catheter comprising: a catheter body with a catheter lumen extending from a proximal catheter portion to a distal catheter portion, the catheter body including a catheter body interior wall having an intermediate guide surface, and the catheter lumen extends along the catheter body interior wall; a manifold assembly coupled with the proximal catheter portion, a manifold lumen extends through the manifold assembly from a proximal manifold portion to a distal manifold portion, the manifold lumen is in communication with the catheter lumen, and the manifold lumen includes an assembly cavity extending around the proximal catheter portion; a fluid jet loop having a loop perimeter surface adjacent to the intermediate guide surface and being coupled with a high pressure tube at the distal catheter portion, the fluid jet loop extends around the loop perimeter surface to form a fluid jet loop lumen, the fluid jet loop includes fluid jet orifices along a tapered loop guide surface, and the tapered loop guide surface tapers continuously both inwardly and distally from the intermediate guide surface of the catheter body interior wall and the loop perimeter surface toward a fluid jet loop inner perimeter and the fluid jet loop lumen; and a composite guide including: a proximal guide insert positioned within the assembly cavity, the proximal guide insert includes a guide insert surface substantially flush with the catheter body interior wall, and the proximal guide insert is configured to guide an instrument past the assembly cavity and into the catheter lumen, and a distal guide including the tapered loop guide surface and the intermediate guide surface of the catheter lumen flushly engaged with a leading edge of the tapered loop guide surface, the distal guide continuously tapering inwardly and distally along at least the tapered loop guide surface from the intermediate guide surface of the catheter body interior wall, wherein the distal guide is configured to guide the instrument over the intermediate guide surface, the tapered loop guide surface and through the fluid jet loop.