Subcutaneously implanted cannula and method for arterial access

Abstract

A catheter with valve for implantation in a vascular structure of a living being. The catheter is in the general shape of a “T” with the top of the “T” implanted within the lumen of a vascular structure, and the leg of the “T” extending out of the vascular structure through an incision in the vascular structure. The lumen of the implanted portion of the catheter completely occupies the lumen of the vascular structure, causing all blood flow through the vascular structure to be directed through the implanted portion of the catheter. A valve is placed in the wall of the implanted portion of the catheter which opens into the lumen of the leg of the “T” of the catheter upon application of sufficient differential pressure between the lumens of the two portions of the catheter. The leg of the “T” is connected to the side wall of the implant portion of the catheter at an angle, such that the axis of the lumen of the leg of the “T” intersects the axis of the lumen of the implanted portion of the catheter at approximately a 45 degree angle.

What is claimed is:  
     
         1 . An arterial cannula comprising: 
 a tubular body having a first end, a second end; and a lumen therebetween, wherein the tubular body is adapted to be implanted within an arterial lumen; and    a tubular access leg having a first end connected to the tubular body at a junction, a second end, and a lumen therebetween, wherein the access tube lumen is fluidly coupled to the tubular body lumen at the junction.    
     
     
         2 . An arterial cannula as in  claim 1 , wherein the tubular body has a length in the range from 10 mm to 50 mm and an outer diameter in the range from 3 mm to 10 mm.  
     
     
         3 . An arterial cannula as in  claim 1 , wherein the access leg has a length in the range from 25 mm to 700 mm and an outer diameter in the range from 3 mm to 10 mm.  
     
     
         4 . An arterial cannula as in  claim 1 , wherein at least a portion of the access leg is sufficiently compliant so that no substantial forces may be transmitted to the tubular body through the access leg.  
     
     
         5 . An arterial cannula as in  claim 4 , wherein at least a portion of the access leg adjacent to the tubular body has a bending stiffness which is less than that of the adjacent tubular body.  
     
     
         6 . An arterial cannula as in  claim 5 , wherein said portion of the access leg has a hoop strength sufficient to withstand an internal pressure of −250 mmHg.  
     
     
         7 . An arterial cannula as in  claim 1 , wherein the tubular body is circumferentially reinforced.  
     
     
         8 . An arterial cannula as in  claim 7 , wherein the circumferential reinforcement comprises a helical wire or circumferential corrugation.  
     
     
         9 . An arterial cannula as in  claim 7 , wherein the access leg is circumferentially reinforced.  
     
     
         10 . An arterial cannula as in  claim 9 , wherein the circumferential reinforcement comprises a helical wire or circumferential corrugation.  
     
     
         11 . An arterial cannula as in  claim 1 , further comprising a pressure-responsive valve at the junction, said valve inhibiting blood flow across the junction in the absence of a pressure differential thereacross.  
     
     
         12 . An arterial cannula as in  claim 11 , wherein the valve is incorporated in the tubular body so that no structure of the valve intrudes into the vascular lumen.  
     
     
         13 . An arterial catheter as in  claim 12 , wherein the valve is a slit valve formed in the tubular body at the junction.  
     
     
         14 . A method for implanting an arterial access cannula within a lumen of an artery, said method comprising: 
 surgically exposing the artery;    making an incision in a wall of the artery;    introducing a tubular body of the access cannula through the incision and into the lumen of the artery so that a lumen of the tubular body is evenly aligned with the arterial lumen and an access leg of the cannula is aligned through the incision; and    closing the incision and securing the tubular body within the arterial lumen.    
     
     
         15 . A method as in  claim 14 , wherein the artery is selected from the group consisting of the proximal ulnar, proximal radial, brachial artery, axillary artery, subclavian artery and synthetic arteries.  
     
     
         16 . A method as in  claim 14 , wherein the lumen of the tubular body is selected to have a cross-sectional dimension substantially equal to that of the blood vessel.  
     
     
         17 . A method as in  claim 16 , further comprising the steps of determining a cross-sectional dimension of the artery and selecting a tubular body having a cross-sectional dimension substantially equal to that of the arterial lumen.  
     
     
         18 . A method as in  claim 14 , wherein the tubular body has an outer diameter in the range from 10 mm to 50 mm and a length in the range from 3 mm to 10 mm.  
     
     
         19 . A method as in  claim 14 , further comprising subcutaneously introducing an arterial port wherein the arterial port is connected or connectable to the access leg of the arterial access cannula.  
     
     
         20 . A method as in  claim 19 , wherein the arterial port is introduced through the incision.  
     
     
         21 . A method as in  claim 19 , wherein the arterial port is introduced through a separate incision remote from the first incision, and thereafter connected to the access leg of the arterial access cannula.  
     
     
         22 . A method as in  claim 14 , further comprising surgically exposing a vein; 
 introducing a venous cannula through the wall of the vein; and    introducing a venous port subcutaneously, wherein the venous port is connected or connectable to the venous catheter.    
     
     
         23 . A method as in  claim 22 , wherein the venous cannula and the venous port are introduced through a single incision.  
     
     
         24 . A method as in  claim 22 , wherein the venous cannula and the venous port are introduced through separate incisions and thereafter connected.  
     
     
         25 . A cannula comprising: 
 a tubular body having a first end, a second end, and a lumen therebetween;    a tubular access leg having a first end connected to the tubular body at a junction; and    a pressure-responsive valve at the junction, said valve inhibiting fluid flow across the valve in the absence of a pressure differential thereacross.    
     
     
         26 . A cannula as in  claim 25 , wherein the tubular body has a length in the range from 10 mm to 50 mm and an outer diameter in the range from 3 mm to 10 mm.  
     
     
         27 . A cannula as in  claim 26 , wherein the access leg has a length in the range from 25 mm to 700 mm and an outer diameter in the range from 3 mm to 10 mm.  
     
     
         28 . A cannula as in  claim 25 , wherein at least a portion of the access leg is sufficiently compliant so that no substantial forces may be transmitted to the tubular body through the access leg.  
     
     
         29 . A cannula as in  claim 28 , wherein at least a portion of the access leg adjacent to the tubular body has a bending stiffness which is less than that of the adjacent tubular body.  
     
     
         30 . A cannula as in  claim 29 , wherein said portion of the access leg has a hoop strength sufficient to withstand an internal pressure of −250 mnmHg.  
     
     
         31 . A cannula as in  claim 25 , wherein the tubular body is circumferentially reinforced.  
     
     
         32 . A cannula as in  claim 31 , wherein the circumferential reinforcement comprises a helical wire or circumferential corrugation.  
     
     
         33 . A cannula as in  claim 31 , wherein the access leg is circumferentially reinforced.  
     
     
         34 . A cannula as in  claim 33 , wherein the circumferential reinforcement comprises a helical wire or circumferential corrugation.  
     
     
         35 . A cannula as in  claim 25 , further comprising a pressure-responsive valve at the junction, said valve inhibiting blood flow across the junction in the absence of a pressure differential thereacross.  
     
     
         36 . A cannula as in  claim 35 , wherein the valve is incorporated in the tubular body so that no structure of the valve intrudes into the vascular lumen.  
     
     
         37 . A cannula as in  claim 36 , wherein the valve is a slit valve formed in the tubular body at the junction.  
     
     
         38 . A cannula as in  claim 25 , wherein the tubular body is adapted to be implanted in a blood vessel.