Methods and systems for treating ischemia

Abstract

Methods for treating total and partial occlusions employ a perfusion conduit which is penetrated through the occlusive material. Oxygenated blood or other medium is then perfused through the conduit in a controlled manner, preferably at a controlled pressure below the arterial pressure, to maintain oxygenation and relieve ischemia in tissue distal to the occlusion. In another aspect, interventional devices, such as stents or balloon catheters, are passed through the perfusion catheter to remove obstructions. Optionally, the occlusion may be treated while perfusion is maintained, typically by introducing a thrombolytic or other agent into the occlusive material using the perfusion conduit or by employing mechanical means to remove the obstruction. Such methods are particularly suitable for treating acute stroke to prevent damage to the cerebral tissue.

What is claimed is:  
     
         1 . A perfusion device for perfusing an oxygenated medium into a patient's cerebral vasculature, comprising: 
 a catheter shaft having a distal portion, the distal portion having a length of at least 10 cm from the distal end, the distal portion also having a maximum outer dimension of no more than 3.2 mm;    a perfusion lumen extending through the shaft, the perfusion lumen having a cross-sectional area of 0.77 mm squared to 7.1 mm squared over the distal portion of the shaft; and    at least one fluid outlet coupled to the lumen for delivering an oxygenated medium into the cerebral vasculature.    
     
     
         2 . The perfusion device of  claim 1 , wherein: 
 the catheter shaft has a maximum outer dimension of no more than 2.4 mm along the distal portion.    
     
     
         3 . The perfusion device of  claim 1 , wherein: 
 the catheter shaft has a maximum outer dimension of no more than 2.0 mm along the distal portion.    
     
     
         4 . The perfusion device of  claim 1 , wherein: 
 the distal portion of the catheter shaft is at least 15 cm long.    
     
     
         5 . The perfusion device of  claim 1 , wherein: 
 the cross-sectional area of the perfusion lumen is at least 1.0 mm squared over the distal portion.    
     
     
         6 . The perfusion device of  claim 1 , wherein: 
 the cross-sectional area of the perfusion lumen is at least 1.5 mm squared over the distal portion.    
     
     
         7 . The perfusion device of  claim 1 , wherein: 
 the cross-sectional area of the perfusion lumen is at least 2.0 mm squared over the distal portion.    
     
     
         8 . The perfusion device of  claim 1 , wherein: 
 the cross-sectional area of the perfusion lumen is at least 4.0 mm squared over the distal portion.    
     
     
         9 . The perfusion device of  claim 1 , further comprising: 
 a pressure transducer positioned along the distal portion of the catheter shaft.    
     
     
         10 . The perfusion device of  claim 1 , further comprising: 
 a balloon attached to the catheter shaft.    
     
     
         11 . The perfusion device of  claim 1 , wherein: 
 the catheter shaft includes only the perfusion lumen and no other lumens.    
     
     
         12 . A balloon catheter which is configured to be advanced through another catheter, the balloon catheter comprising: only one lumen and a balloon, the balloon being coupled to the lumen for inflating the balloon, the balloon catheter having no other lumens and having no structure, guidewire lumen or distal opening for guiding the catheter along a guidewire.  
     
     
         13 . The balloon catheter of  claim 12 , wherein the balloon catheter has a tapered shaft.  
     
     
         14 . The balloon catheter of  claim 13 , wherein the catheter has a maximum outer dimension of no more than 1.6 mm excluding the balloon along a length of 5 cm from a distal end.  
     
     
         15 . The balloon catheter of  claim 12 , wherein a stent is mounted on the balloon.  
     
     
         16 . A catheter for accessing the cerebral vasculature, comprising: 
 a shaft having a proximal end, a distal end, a proximal portion and a distal portion, the distal portion extending for a length of at least 5 cm from the distal end and the proximal portion extending for a length of at least 75 cm; and    a lumen extending through the shaft, the lumen having a cross-sectional area of 0.45 to 2.3 mm 2  along the distal portion and a cross-sectional area of 2.0-7.6 mm 2  along the proximal portion.    
     
     
         17 . The catheter of  claim 16 , wherein the distal portion extends for at least 10 cm from the distal end.  
     
     
         18 . The catheter of  claim 16 , wherein the lumen has a cross-sectional area of 2.8-5.6 mm 2  along the proximal portion.  
     
     
         19 . The catheter of  claim 16 , wherein the lumen has a cross-sectional area of 0.62-1.7 mm 2  along the distal portion.  
     
     
         20 . The catheter of  claim 16 , wherein the lumen is surrounded by a wall having a wall thickness, the wall thickness being no more than 0.20 mm.  
     
     
         21 . The catheter of  claim 16 , wherein the lumen is surrounded by a wall having a wall thickness, the wall thickness being no more than 0.15 mm.  
     
     
         22 . The catheter of  claim 16 , wherein the lumen has a circular cross-sectional shape and a diameter of 0.76-1.7 mm along the distal portion; and the shaft has an outer diameter along the distal portion of no more than 0.40 mm larger than the diameter of the lumen.  
     
     
         23 . The catheter of  claim 16 , wherein the proximal portion of the shaft extends for at least 100 cm.  
     
     
         24 . The catheter of  claim 16 , wherein the shaft has an intermediate section between the proximal and distal sections, and the intermediate section has a cross-sectional area smaller than the proximal section and larger than the distal section.  
     
     
         25 . The catheter of  claim 24 , wherein the intermediate section has a length of at least 15 cm.  
     
     
         26 . The catheter of  claim 25 , wherein the intermediate section is tapered and has a length of at least 20 cm.