Assemblies, systems, and methods for infusing therapeutic agents into the body

Abstract

An infusion catheter assembly has the ability to infinitely titrate the length of a porous fluid distribution section in situ. The infusion catheter assembly thereby provides a length of infusion that can be infinitely varied over a prescribed range, to control the effective infusion length and the rate of infusion. Using the infusion catheter assembly, a physician has the capability to treat only the length of the vessel desired, thereby preventing excessive drug/patient exposures. The porous fluid distribution section can include an array of spaced apart apertures that vary in size and/or density along the length of the porous fluid distribution section, such that the flow rate remains essentially constant for a given inlet pressure independent of the effective infusion length.

1 . (canceled) 
     
     
         2 . (canceled) 
     
     
         3 . An infusion catheter having variable infusion length, said catheter comprising:
 an outer catheter having a lumen extending therethrough and porous fluid distribution section adjacent a distal portion thereof;   an inner catheter having a lumen extending therethrough and a fluid exit port adjacent a distal portion thereof, the inner catheter slidably disposed in the lumen of the outer catheter; and   an expandable barrier disposed on a distal portion of the inner catheter, the expandable barrier having an expanded configuration and a collapsed configuration, wherein in the collapsed configuration the inner catheter is configured to be slidably advanced or retracted in the outer catheter lumen, and wherein the expanded configuration the expandable barrier engages an inner wall of the outer catheter forming a seal to prevent fluid flow therepast such that fluid introduced into the inner catheter passes through the fluid exit port into the lumen of the outer catheter and exits the porous fluid distribution section distal of the expandable barrier, and   wherein retraction or advancement of the inner catheter relative to the outer catheter controls the infusion length of the porous fluid distribution section from which fluid flows.   
     
     
         4 . The catheter of  claim 3 , wherein the porous fluid distribution section comprises a plurality of apertures extending through a wall in the outer catheter. 
     
     
         5 . The catheter of  claim 3 , wherein the porous fluid distribution section comprises a plurality of apertures having variable size or density such that fluid flow along the infusion length is at a constant flow rate. 
     
     
         6 . The catheter of  claim 6 , wherein the plurality of apertures have a larger size or have a lower density adjacent a distal portion of the portion of the porous fluid distribution section relative to a proximal portion of the porous fluid distribution section. 
     
     
         7 . The catheter of  claim 3 , wherein the expandable barrier comprises a balloon. 
     
     
         8 . The catheter of  claim 3 , wherein the expandable barrier comprises an umbrella-like mechanism. 
     
     
         9 . The catheter of  claim 3 , further comprising one or more radiopaque markers disposed on the inner catheter or the outer catheter to allow visualization of the infusion length. 
     
     
         10 . The catheter of  claim 3 , wherein the fluid comprises a therapeutic agent. 
     
     
         11 . A method for infusing a therapeutic agent to a target treatment region, said method comprising:
 providing an infusion catheter having an inner catheter and an outer catheter, the inner catheter having a barrier mechanism disposed thereon, the outer catheter having a porous fluid distribution section;   advancing the infusion catheter toward the target treatment region such that the porous fluid distribution section is disposed adjacent the target treatment region;   advancing or retracting the inner catheter relative to the outer catheter to control a position of the expandable barrier mechanism along the porous fluid distribution section;   actuating the expandable barrier mechanism to form a fluid seal along the porous fluid distribution section, and wherein a region along the porous fluid distribution section distal of the fluid seal forms an infusion length, the infusion length matching a length of the target treatment region; and   introducing the therapeutic agent into the inner catheter and passing the therapeutic agent from the inner catheter into the outer catheter and out the porous fluid distribution section, wherein the therapeutic agent only exits the infusion length.   
     
     
         12 . The method of  claim 11 , wherein advancing the infusion catheter comprising advancing the infusion catheter in a blood vessel. 
     
     
         13 . The method of  claim 11 , wherein advancing the infusion catheter comprising advancing the infusion catheter through a tissue mass or an organ. 
     
     
         14 . The method of  claim 11 , wherein the target treatment region comprises a tumor. 
     
     
         15 . The method of  claim 11 , wherein the target treatment region comprises a thrombosis. 
     
     
         16 . The method of  claim 11 , wherein advancing or retracting comprises slidably moving the inner catheter relative to the outer catheter. 
     
     
         17 . The method of  claim 11 , wherein actuating the expandable barrier mechanism comprises radially expanding the barrier mechanism. 
     
     
         18 . The method of  claim 11 , wherein actuating the expandable barrier mechanism comprises radially expanding a balloon. 
     
     
         19 . The method of  claim 11 , further comprising maintaining a constant flow rate of the therapeutic agent along the infusion length of the porous fluid distribution section. 
     
     
         20 . The method of  claim 11 , wherein the therapeutic agent comprises a thrombolytic agent or a tumor treatment agent. 
     
     
         21 . The method of  claim 11 , further comprising adjusting the infusion length by visualizing advancement or retraction of the inner catheter relative to the outer catheter with radiographic imaging.