Devices and methods for cannulating a blood vessel

Abstract

A cannula has a distal portion which is angled relative to a proximal portion. The distal portion is straightened during introduction with a stiffening element. After introduction, the stiffening element is removed so that the distal portion angulates relative to the proximal portion so that the cannula can be moved out of the surgical field. The cannula preferably includes a stabilizing ring having suture holders. The stabilizing ring is also preferably angled relative to the cannula.

What is claimed is:  
     
         1 . A cannula for infusing or withdrawing fluids to and from a patient, comprising; 
 a lumen;    a proximal portion;    a distal portion extending from the proximal portion, the distal portion being angled relative to the proximal portion in an unbiased condition;    a distal tip at the end of the distal portion;    a stiffening element positionable in the lumen of the cannula, the stiffening element straightening the angle between the proximal and distal portions when positioned in the lumen.    
     
     
         2 . The cannula of    claim 1   , wherein: 
 the distal portion has an axis which forms an angle of between 100 degrees with the proximal portion when in the unbiased position.    
     
     
         3 . The cannula of    claim 1   , wherein: 
 the proximal portion has a longitudinal axis. the proximal portion terminating at a proximal end of the distal portion; and    the distal tip being separated from the proximal end of the distal portion by a distance of between 15-35 mm.    
     
     
         4 . The cannula of    claim 1   , further comprising: 
 the cannula has stabilizing ring, the stabilizing ring being attached to the distal portion and forming an angle with the distal portion of about 10-30 degrees.    
     
     
         5 . The cannula of    claim 4   , wherein: 
 the stabilizing ring has at least one suture holder.    
     
     
         6 . The cannula of    claim 4    wherein: 
 the stiffening element has a tip which extends beyond the distal tip when the stiffening element is positioned in the lumen.  
 
     
     
         7 . The cannula of    claim 6   , wherein: 
 the tip of the stiffening element is rounded and atraumatic to facilitate atraumatic introduction into the patient.    
     
     
         8 . The cannula of    claim 6   , wherein: 
 the stiffening element has an incising element positioned therein, the incising element being coupled to an actuator for moving the incising element from a retracted position to an exposed position, the incising element extending beyond the tip of the stiffening element in the exposed position.    
     
     
         9 . The cannula of    claim 1   , wherein: 
 the lumen has a size of 18-24 French.    
     
     
         10 . The cannula of    claim 1   , wherein: 
 the distal portion has a curved shape.    
     
     
         11 . The cannula of    claim 1    wherein: 
 the distal portion has a bi-linear shape.  
 
     
     
         12 . The cannula of    claim 1   , further comprising: 
 a suture ring mounted to the distal portion; 
 the distal portion extending 10-30 mm and the suture ring being mounted 5-15 mm from the distal end.  
   
     
     
         13 . A method of cannulating a patient, comprising the steps of: 
 providing a cannula having a lumen, a proximal portion, a distal portion extending from the proximal portion, a distal tip at the end of the distal portion, the distal portion being angled relative to the proximal portion in an unbiased condition;    introducing a stiffening element into the lumen of the cannula, the stiffening element straightening the angle between the proximal and distal portions;    incising a blood vessel to create an incision;    passing the distal end of the cannula through the incision; and    removing the stiffening element after the passing step so that the proximal and distal portions angulate relative to one another.    
     
     
         14 . The method of    claim 13   , wherein: 
 the providing step is carried out with the distal portion having an axis which forms an angle of between 80-120 degrees with the proximal portion when in the unbiased position.    
     
     
         15 . The method of    claim 13   , wherein: 
 the providing step is carried out with the cannula having a stabilizing ring attached to the distal portion.    
     
     
         16 . The method of    claim 15   , wherein: 
 the providing step is carried out with the stabilizing ring forming an angle with the distal portion of about 10-30 degrees.    
     
     
         17 . The method of    claim 13   , wherein: 
 the introducing step is carried out with the stiffening element having a tip which extends beyond the distal tip.    
     
     
         18 . The method of    claim 13   , wherein: 
 the introducing step is carried out with the tip of the stiffening element being rounded and atraumatic.    
     
     
         19 . The method of    claim 13   , wherein: 
 the introducing step is carried out with the stiffening element having an incising element positioned therein, the incising element being coupled to an actuator for moving the incising element from a retracted position to an exposed position, the incising element extending beyond the tip of the stiffening element in the exposed position; and    the incising step is carried out with the incising element.    
     
     
         20 . The method of    claim 13   , wherein: 
 the providing step is carried out with the lumen having a size of 18-24 French.    
     
     
         21 . The method of    claim 13   , wherein: 
 the providing step is carried out with the distal portion having a curved shape.    
     
     
         22 . The method of    claim 13   , wherein: 
 the providing step is carried out with the distal portion having a bi-linear shape.    
     
     
         23 . The method of    claim 13   , wherein: 
 a providing step is carried out with the cannula having a stabilizing ring mounted to the distal portion, the distal portion extending 25-35 mm and the suture ring being mounted 5-15 mm from the distal end.