Devices and methods for low pressure tumor embolization

Abstract

A method of transarterial embolization agent delivery at a low pressure is provided. The method comprises advancing a delivery device with an occlusion structure in a retracted non-occlusive configuration through a supply artery to a vascular position in the supply artery that is in the vicinity of a target anatomical structure, the target structure having terminal capillary beds, expanding the occlusion structure from the retracted non-occlusive configuration to an expanded occlusive configuration, lowering a mean arterial pressure in a vascular space distal to the expanded occlusion structure, redirecting fluid flow from the collateral vessels toward the lowered pressure vascular space and into the target anatomical structure, injecting an embolization agent through the delivery device and into the lowered pressure vascular space, and delivering the embolization agent from the lowered pressure vascular space into the target anatomical structure. Other catheter assemblies and methods of use are also disclosed.

What is claimed is: 
     
         1 . A balloon catheter, comprising:
 an outer elongate shaft;   an inner elongate shaft with a delivery lumen therein, the inner elongate shaft radially within the inner elongate shaft and extending distally beyond the outer elongate shaft;   an elastic inflatable balloon comprising a silicone material, the inflatable balloon having proximal and distal ends secured to a distal end region of the catheter,
 wherein the outer elongate shaft and the inner elongate shaft define a fluid lumen in fluid communication with an internal volume of the inflatable balloon to allow fluid to be advanced through the fluid lumen and into the internal volume of the balloon to inflate the balloon, 
 wherein a distal end of the inflatable balloon is secured to a section of the inner elongate shaft that extends beyond a distal end of the outer elongate shaft, and 
 wherein the proximal end of the inflatable balloon is compressed under a proximal collar, and wherein the distal end of the inflatable balloon is compressed under a distal collar, wherein at least one of the proximal collar and the distal collar comprises a heat shrink material; and 
   a catheter extension section including a distal tip that extends distally beyond the distal end of the inflatable balloon.   
     
     
         2 . The balloon catheter of  claim 1 , wherein the distal collar has a length from 2 mm to 10 mm. 
     
     
         3 . The balloon catheter of  claim 1 , wherein at least one of the proximal collar and the distal collar comprises a heat shrink material. 
     
     
         4 . The balloon catheter of  claim 3 , wherein the proximal collar comprises a heat shrink material and the distal collar comprises a heat shrink material. 
     
     
         5 . The balloon catheter of  claim 1 , wherein the inflatable balloon is elastic and comprises a silicone material. 
     
     
         6 . The balloon catheter of  claim 5 , wherein the inflatable balloon consists essentially of a silicone material. 
     
     
         7 . The balloon of  claim 1 , wherein the inflatable balloon has an unexpanded configuration in which it is disposed at or below an outer surface of the outer elongate shaft. 
     
     
         8 . The balloon catheter of  claim 1 , wherein the proximal end of the inflatable balloon is secured relative to the outer elongate shaft. 
     
     
         9 . The balloon catheter of  claim 1 , further comprising a catheter extension section including a distal tip that extends distally beyond the distal end of the inflatable balloon. 
     
     
         10 . The balloon catheter of  claim 8 , wherein the catheter extension has a length from 2 mm-30 mm. 
     
     
         11 . A system for delivering an embolizing agent to a tumor, the system comprising:
 a catheter, the catheter comprising:
 a catheter body having a proximal end, a distal end, a balloon inflation lumen, and an embolizing agent delivery lumen; 
 a catheter extension section that extends axially beyond the distal end of the catheter body, wherein the catheter extension has a central longitudinal axis and a diameter less than the diameter of the catheter body, wherein a nose piece is adapted to the catheter extension; and 
 an inflatable balloon disposed on the catheter extension and held within a pocket between the distal end of the catheter body and a proximal end of the nose piece, the balloon, when in an unexpanded configuration, is positioned substantially below an outer surface of the catheter body, the balloon having an inner surface that at least partially defines an interior volume, the balloon being configured such that the interior volume can be in fluid communication with the inflation lumen of the catheter body to inflate the balloon, the balloon having an outer surface that is concentric with the central longitudinal axis of the catheter extension when the balloon is inflated, the balloon having a proximal surface and a distal surface, wherein the balloon is provided with a plurality of channels that extend through the balloon, the channels configured to provide fluid communication between the proximal surface of the balloon and the distal surface of the balloon, wherein the channels are offset from the central longitudinal axis and are equally spaced about the circumference of the catheter to provide symmetrical blood bypass through the balloon, wherein the balloon comprises valves configured to affect fluid flow through the channels; 
 a pressure sensor configured to sense a fluid pressure associated with a region located distally from the distal surface of the balloon; 
   
     
     
         12 . A method of transarterial embolization agent delivery at a low pressure, the method comprising:
 advancing a delivery device with an occlusion structure in a retracted non-occlusive configuration, through a supply artery having a plurality of collateral vessels that branch therefrom and being in fluid communication with a target anatomical structure, to a vascular position in the supply artery that is in the vicinity of the target anatomical structure, the target structure having terminal capillary beds;   expanding the occlusion structure from the retracted non-occlusive configuration to an expanded occlusive configuration;   lowering a mean arterial pressure in a vascular space distal to the expanded occlusion structure;   redirecting fluid flow from the collateral vessels toward the lowered pressure vascular space and into the target anatomical structure;   injecting an embolization agent through the delivery device and into the lowered pressure vascular space; and   delivering the embolization agent from the lowered pressure vascular space into the target anatomical structure,   wherein the mean arterial pressure of the lowered pressure vascular space is kept below an un-occluded starting pressure by at least 10% of the difference between the un-occluded starting pressure and a stabilized occluded pressure during the injecting step.