Medical fluid delivery system

Abstract

A medical fluid delivery system is provided including a steerable, guide catheter, a delivery catheter adapted for deployment at a targeted tissue site using the steerable guide catheter, the delivery catheter including a proximal port, a distal port, and a lumen extending between the proximal and distal ports; a distal fixation element coupled to the delivery catheter so as to position the distal port adjacent the targeted tissue site; and a flexible hollow needle adapted to be advanced through the delivery catheter lumen, the flexible needle including a tissue-piercing distal tip for extending from the distal port of the delivery catheter for advancement into the targeted tissue site and a proximal end for extending from the proximal port of the delivery catheter through which a medical fluid is delivered.

What is claimed is: 
     
         1 . A method of delivering medical fluid to a tissue, the method comprising:
 navigating a delivery catheter body through vasculature to a fixation site of a targeted tissue;   fixing the delivery catheter body to the fixation site using a fixation member extending from a distal end of the delivery catheter body and having a central axis symmetric with a central axis of the delivery catheter body;   advancing a flexible needle out from a distal port located on the delivery catheter body, the distal port asymmetric to the central axis of the delivery catheter body, the flexible needle extending asymmetrically with the delivery catheter body central axis and along a first pathway within the targeted tissue;   retracting the needle from the first pathway of the targeted tissue;   rotating the delivery catheter, while maintaining fixation at the fixation site, to reposition the distal port along a perimeter of the tissue fixation site;   advancing the needle out from the repositioned distal port and along a second pathway within the targeted tissue; and   delivering medical fluid through the needle to the targeted tissue along the first and second pathways.   
     
     
         2 . The method of  claim 1 , further comprising verifying a position of the delivery catheter with respect to the fixation site by measuring a first impedance between the advanced needle and an electrode of the delivery catheter. 
     
     
         3 . The method of  claim 2  further comprising advancing a second flexible needle out from a second distal port located on the delivery catheter body,
 wherein measuring the impedance comprises measuring a second impedance using the second advanced needle, 
 wherein verifying the position comprises comparing the first impedance and the second impedance. 
 
     
     
         4 . The method of  claim 3 , wherein measuring the impedance comprises measuring a second impedance advanced along the second pathway,
 wherein verifying the position comprises comparing the first impedance and the second impedance.   
     
     
         5 . The method of  claim 3  further comprising:
 detecting a canted distal end of the delivery catheter body with respect to a surface of the tissue fixation site in response to the measured impedance; and 
 adjusting the delivery catheter body position in response to detecting the canted distal end. 
 
     
     
         6 . The method of  claim 2 , wherein delivering the medical fluid comprises a continuous injection delivered along the first pathway as the needle is retracted. 
     
     
         7 . The method of  claim 2 , wherein delivering the fluid comprises a plurality of bolus injections delivered at discrete locations along the first pathway as the needle is retracted. 
     
     
         8 . The method of  claim 1  wherein the flexible needle includes a pre-formed curve in proximity to the tissue-piercing distal tip such that the tip extends co-planar within the body tissue. 
     
     
         9 . A medical fluid delivery system for advancing through vasculature, comprising:
 navigating a delivery catheter body through vasculature to a fixation site of a targeted tissue;   fixing the delivery catheter body to the fixation site using a fixation member extending from a distal end of the delivery catheter body and having a central axis symmetric with a central axis of the delivery catheter body;   advancing a flexible hollow needle out from a distal port located on the delivery catheter body, the distal port asymmetric to the central axis of the delivery catheter body, the flexible hollow needle extending asymmetrically with the delivery catheter body central axis and along a first pathway within the targeted tissue;   retracting the needle from the first pathway of the targeted tissue;   rotating the delivery catheter, while maintaining fixation at the fixation site, to reposition the distal port along a perimeter of the tissue fixation site;   advancing the needle out from the repositioned distal port and along a second pathway within the targeted tissue; and   delivering medical fluid through the needle to the targeted tissue along the first and second pathways,   wherein the needle includes a pre-formed curve in proximity to the tissue-piercing distal tip such that the tip is directed away from the distal fixation element after passing beyond the distal port of the delivery catheter body.   
     
     
         10 . The method of  claim 9 , wherein the flexible hollow needle is formed of a material comprising a shape memory alloy. 
     
     
         11 . The method of  claim 9 , wherein the delivery catheter body lumen is formed to include a curve near the distal port such that the distal tip of the flexible hollow needle is directed away from the distal fixation element when extending from the distal port of the catheter body. 
     
     
         12 . The method of  claim 9 , wherein the lumen of the delivery catheter body comprises a rotational stopping member extending along an inner diameter of the delivery catheter body lumen. 
     
     
         13 . The method of  claim 12 , wherein the needle comprises a groove interacting with the stopping member to prevent rotation of the needle relative to the delivery catheter body. 
     
     
         14 . The method of  claim 9 , wherein the delivery catheter body further comprises a central lumen extending between a proximal end of the catheter body and a distal end of the catheter body along the catheter body central axis. 
     
     
         15 . The method of  claim 14 , wherein the distal fixation element extends through the central lumen allowing independent rotation of the delivery catheter body with respect to the fixation element. 
     
     
         16 . The method of  claim 9  wherein the delivery catheter body comprises
 a plurality distal ports located on the catheter body asymmetric with the catheter body central axis, and 
 a plurality of lumens extending through the delivery catheter body, each one of the plurality of lumens terminating at one of the plurality of distal ports; and 
 a plurality of flexible needles each having a tissue-piercing distal tip extending from one of the plurality of distal ports.