Methods and apparatus for crossing vascular occlusions

Abstract

Methods and apparatus for crossing totally to substantially occluded blood vessels by passing a redirectable wire such as a guidewire from a relatively proximal point past the occlusion within a subintimal space formed between the intimal layer and the adventitial layer of a blood vessel wall. The wire may be advanced to a point distal to the occlusion, and thereafter deflected back into the blood vessel lumen, typically using a deflecting catheter which is advanced over the guidewire after it has been positioned within the subintimal space. The deflecting catheter may include a flapper valve assembly or preformed actuator wire for redirecting the guidewire. After the guidewire is returned to the blood vessel lumen, the deflecting catheter may be withdrawn, and the guidewire may be available for introduction of other interventional and diagnostic catheters for performing procedures such as stenting.

What is claimed is:  
     
         1 . A guidewire deflection system comprising: 
 a catheter body having a proximal end, a distal end, a longitudinal axis, and at least one lumen extending along the catheter body;    a nosecone formed at the distal end of the catheter body having a distal opening in communication with the catheter body lumen, a lateral opening spaced relatively proximal to the distal opening that is in communication with the catheter body lumen, and an inclined surface formed proximally adjacent to the lateral opening; and    a cannula having a proximal end, a distal end, and at least one passageway extending through at least a distal portion of the cannula, wherein the distal end of the cannula is configured to deflect away from the longitudinal axis of the catheter body when the distal end thereof engages the inclined surface adjacent to the lateral opening.    
     
     
         2 . A guidewire deflection system as recited in    claim 1   , wherein the distal portion of the cannula has a pre-formed shape resilient curve and is slidably positioned within the lumen of the catheter body, and wherein the distal portion has a relatively axially aligned configuration with the lumen when the cannula is positioned within the catheter body, and a relatively curved configuration with the lumen when the cannula travels along the inclined surface and through the lateral opening of the catheter body when the cannula is distally advanced through the lumen within the catheter body.  
     
     
         3 . A guidewire deflection system as in    claim 2   , wherein the pre-formed shape resilient curve at the distal portion of the cannula extends over an arc in the range from 15 to 135 degrees.  
     
     
         4 . A guidewire deflection system as in either    claim 2   , wherein the pre-formed shape resilient curve has a radius in the range from 1 mm to 20 mm.  
     
     
         5 . A guidewire deflection system as recited in    claim 1   , wherein the cannula is configured for slidable movement through the lateral opening.  
     
     
         6 . A guidewire deflection system as recited in    claim 1   , further comprising a guidewire configured to pass through the passageway of the cannula.  
     
     
         7 . A guidewire deflection system as recited in    claim 6   , wherein the guidewire is configured for slidable movement through the distal opening of the nosecone.  
     
     
         8 . A guidewire deflection system as recited in    claim 6   , wherein the guidewire has a sharpened distal tip.  
     
     
         9 . A guidewire deflection system as in    claim 6   , wherein the guidewire comprises means for imaging tissue surrounding the wire.  
     
     
         10 . A guidewire deflection system as in    claim 1   , wherein the cannula is formed with a self-penetrating distal end.  
     
     
         11 . A guidewire deflection system as recited in    claim 10   , wherein the self-penetrating distal end includes a sharpened distal tip.  
     
     
         12 . A guidewire deflection system as recited in    claim 1   , wherein the cannula includes a radiopaque marker substantially near its distal end.  
     
     
         13 . A guidewire deflection system as recited in    claim 1   , wherein the distal end of the cannula includes a radiopaque marker.  
     
     
         14 . A guidewire deflection system as recited in    claim 1   , wherein the distal end of the catheter body includes a fluoroscopically visible marker substantially near its distal end to permit visual determination of the rotational orientation of the nosecone.  
     
     
         15 . A guidewire deflection system as in    claim 1   , wherein the nosecone is formed with a substantially circular cross-section.  
     
     
         16 . A guidewire deflection system as in    claim 1   , wherein the nosecone is formed with a wedge shaped cross-section.  
     
     
         17 . A guidewire deflection system as in    claim 1   , wherein the nosecone is formed with a substantially elliptical cross-section.  
     
     
         18 . A guidewire deflection system as in    claim 1   , further comprising a hub rotationally secured to the proximal end of the catheter body to controllably rotate the cannula and the catheter body.  
     
     
         19 . A guidewire deflection system as in    claim 18   , wherein the hub includes a cannula controller connected to the cannula for controlling the slidable movement of the cannula within the catheter body.  
     
     
         20 . An intravascular catheter comprising: 
 a catheter shaft having a distal end and a longitudinal lumen;    a nosecone positioned at the distal end of the catheter shaft having a first port in communication with the longitudinal lumen formed with a first transverse cross-sectional area, and a second port in communication with the longitudinal lumen formed with a second transverse cross-sectional area relatively smaller than the first transverse cross-sectional area;    a cannula having a passageway that is slidably positioned within at least a portion of the longitudinal lumen of the catheter shaft, and is configured for passage through the first port but not through the second port of the nosecone; and    a guidewire that is slidably disposed within at least part of the cannula passageway and is configured for passage through the second port.    
     
     
         21 . An intravascular catheter as recited in    claim 20   , wherein the nosecone includes an imaging component that provides directional orientation.  
     
     
         22 . An intravascular catheter as recited in    claim 20   , wherein the nosecone includes a radiopaque marker.  
     
     
         23 . An intravascular catheter as recited in    claim 20   , wherein the nosecone defines the first port as a substantially circular orifice and the second port as a substantially elliptical orifice.  
     
     
         24 . An intravascular catheter as recited in    claim 23   , wherein the nosecone further defines an inclined surface leading to the second port.  
     
     
         25 . An intravascular catheter as recited in    claim 24   , wherein the nosecone defines the first port and the second port, further defines an inclined surface.  
     
     
         26 . A redirectable intravascular guidewire catheter comprising: 
 a catheter shaft having a distal end, a proximal end, a longitudinal axis, and at least one lumen extending along at least a portion of catheter shaft; and    a guidewire deflector formed at the distal end of the catheter shaft having a distal end port, a lateral port, and a flapper assembly with a deflectable extension having a first position that directs a guidewire tip through the distal end port when the guidewire tip is positioned relatively distal to the deflectable extension, and a second position that directs the guidewire tip through the lateral port when the tip is positioned relatively proximal to the deflectable extension and advanced thereafter in a relatively distal direction.    
     
     
         27 . A redirectable intravascular guidewire catheter as recited in    claim 26    further comprising a guidewire that is slidably positioned within the lumen of the catheter shaft.  
     
     
         28 . A redirectable intravascular guidewire catheter as recited in    claim 26   , wherein at least a portion of the flapper assembly is formed of a radiopaque material to provide an orientation marker for directional placement of a guidewire.  
     
     
         29 . A redirectable intravascular guidewire catheter as recited in    claim 26   , wherein the flapper assembly is formed with a relatively distal collar that is positioned substantially adjacent to the distal end port.  
     
     
         30 . A redirectable intravascular guidewire catheter as recited in    claim 26   , wherein the distal collar is includes radiopaque material.  
     
     
         31 . A redirectable intravascular guidewire catheter as recited in    claim 26   , wherein the distal end of the catheter shaft is formed with an exterior surface, and wherein the relatively distal collar of the flapper valve is positioned on the exterior surface of the distal end of the catheter shaft.  
     
     
         32 . A redirectable intravascular guidewire catheter as recited in    claim 26   , wherein the guidewire deflector and the catheter shaft are integrally formed.  
     
     
         33 . A redirectable intravascular guidewire catheter as recited in    claim 26   , wherein the proximal end of the catheter shaft includes a stainless steel wire, and wherein the catheter shaft is formed with an opening relatively distal to the wire for passage of a guidewire.  
     
     
         34 . A redirectable guidewire catheter comprising: 
 a catheter shaft formed with a distal end, and having a first lumen and a second lumen each extending along the catheter shaft respectively to a first distal opening and a second distal opening;    an actuator wire slidably positioned within the first lumen of the catheter shaft, wherein the actuator wire is formed with a preformed distal end to provide an actuated position that is biased towards the second distal opening when advanced relatively distal through the first distal opening; and    a guidewire slidably positioned within the second lumen of the catheter shaft that may be deflected when advanced relatively distal through the second distal opening and when the actuator wire is placed in its actuated position.    
     
     
         35 . A redirectable guidewire catheter as recited in    claim 34   , wherein at least a portion of the actuator wire is formed of a half-cylinder hypotube.  
     
     
         36 . A redirectable guidewire catheter as recited in    claim 34   , wherein the preformed distal end of the actuator wire is formed with a arc-shaped cross-section.  
     
     
         37 . A redirectable guidewire catheter as recited in    claim 34   , wherein the actuator wire extends beyond the outer surface of the catheter shaft.  
     
     
         38 . A redirectable guidewire catheter comprising: 
 a catheter shaft formed with a distal portion and a longitudinal axis, and wherein the catheter shaft has a first lumen and a second lumen each extending within the distal portion of the catheter shaft;    a nosecone formed at the distal portion of the catheter shaft, wherein the nosecone includes a distal orifice and an interior region, and wherein the interior region of the nosecone is formed with a tapered surface and is in communication with the first and second lumens;    an actuator wire formed with a distal tip that is slidably positioned within the first lumen of the catheter shaft, wherein the distal tip of the actuator wire is redirected substantially away from the longitudinal axis of the catheter shaft when advanced relatively distal along the tapered surface of the nosecone and through the nosecone orifice; and    a guidewire slidably positioned within the second lumen of the catheter shaft that may be deflected away from the longitudinal axis of the catheter shaft by contacting the redirected actuator wire when the guidewire is advanced relatively distal through the distal orifice.    
     
     
         39 . A redirectable guidewire catheter as recited in    claim 38   , wherein the catheter shaft has a distal most end, and wherein the orifice is formed at the distal most end of the catheter shaft.  
     
     
         40 . A redirectable guidewire catheter as recited in    claim 39   , wherein the catheter shaft and the nosecone are integrally formed.  
     
     
         41 . A redirectable guidewire catheter as recited in    claim 38   , wherein the first and the second lumen are arranged in a side-by-side configuration.  
     
     
         42 . An intravascular catheter for selectively deflecting a guidewire comprising: 
 a catheter body formed with a distal end and a longitudinal lumen formed along at least a portion of the catheter body;    a support tube having a distal tube end, a proximal tube end, a tube port formed at the distal tube end, and a conduit formed within the support tube in communication with the tube port, wherein the distal tube end is formed with a cut-out portion, and wherein the support tube is slidably and rotatably positioned within the longitudinal lumen of the catheter body; and    a cannula having a distal cannula end, a cannula port formed at the distal cannula end, and at least one passageway extending through at least a distal end portion of the cannula that is in communication with the cannula port, wherein the distal portion of the cannula has a pre-formed shape resilient curve, and wherein the cannula is slidably positioned within the conduit of the support tube.    
     
     
         43 . An intravascular catheter as recited in    claim 42   , wherein the support tube has a longitudinal axis, and wherein the distal portion of the cannula is relatively aligned with respect to the longitudinal axis of the support tube when the cannula is positioned within the support tube, and is relatively askew with respect to the longitudinal axis of the support tube when the distal cannula end extends beyond the distal end of the catheter body.  
     
     
         44 . An intravascular catheter as recited in    claim 43   , further comprising a guidewire with a distal tip positioned within at least a portion of the cannula passageway, wherein the distal tip of the guidewire is deflected in substantially the same direction as the distal portion of the cannula.  
     
     
         45 . An intravascular catheter as recited in    claim 43   , wherein the proximal tube end of the support tube is connected to a rotating assembly to rotate the support tube relative to the catheter body.  
     
     
         46 . An intravascular catheter for selectively deflecting a guidewire comprising: 
 a catheter body formed with a distal end, a catheter port formed at the distal end of the catheter body, a longitudinal axis, and a longitudinal lumen extending within at least a distal portion of the catheter body in communication with the catheter port;    a cannula having a distal cannula end, a cannula port formed at the distal cannula end, and at least one passageway formed within at least a distal portion of the cannula in communication with the cannula port, wherein the cannula is slidably positioned within the longitudinal lumen of the catheter body; and    a support tube connected to the distal cannula end, wherein the support tube is formed with a distal tube end section, a proximal tube end section, and a backbone connecting the distal and the proximal tube end sections.    
     
     
         47 . An intravascular catheter as recited in    claim 46   , wherein the support tube is preformed with a predetermined shape to deflect the distal cannula end away from the longitudinal axis of the catheter body when the distal cannula end is extended past the distal end of the catheter body.  
     
     
         48 . An intravascular catheter as recited in    claim 46   , wherein the distal cannula end is preformed with a predetermined shape that deflects away from the longitudinal axis of the distal cannula end when extended past the distal end of the catheter body.  
     
     
         49 . An intravascular catheter as recited in    claim 46   , wherein the cannula is slidably movable within the longitudinal lumen of the catheter body.  
     
     
         50 . An intravascular catheter as recited in    claim 46   , wherein the backbone of the support tube includes a plurality of cut-out rib sections.  
     
     
         51 . A redirectable intravascular guidewire catheter comprising: 
 a catheter shaft having a distal end, a proximal end, a longitudinal axis, a first port formed at the distal end of the shaft, a second port spaced relatively proximal to the distal end of the shaft, and at least one lumen extending along at least a portion of the longitudinal axis of the catheter shaft in communication with the first and second ports; and    a guidewire deflector formed within a distal extremity of the catheter shaft having a first surface that directs an end portion of a guidewire between the catheter shaft lumen and the first port, and a second surface that directs the end portion of the guidewire between the catheter shaft lumen and the second port.    
     
     
         52 . The redirectable intravascular guidewire catheter as recited in    claim 51   , wherein the guidewire deflector includes a flapper valve having a first position that provides the first surface for contact with the guidewire, and a second position that provides the second surface for contact with the guidewire.  
     
     
         53 . A method for crossing a substantially occluded blood vessel, said method comprising: 
 selecting a guidewire with a deflectable distal tip configured for advancement within a lumen of a blood vessel wall;    creating a longitudinal dissection plane within a wall the blood vessel by inserting the guidewire into blood vessel wall from within the blood vessel lumen at a proximal location relative to a vascular occlusion;    forming a channel along the dissection plane within the blood vessel wall by advancing the guidewire within the blood vessel wall in a relatively distal direction; and    selectively deflecting the distal tip of the guidewire at a relatively distal location relative to the proximal location back into the blood vessel lumen.    
     
     
         54 . A method as recited in    claim 53   , wherein the blood vessel is an artery.  
     
     
         55 . A method as recited in    claim 54   , wherein the artery is coronary artery.  
     
     
         56 . A method as recited in    claim 53   , further comprising performing an interventional or diagnostic procedure over the guidewire.  
     
     
         57 . A method as recited in    claim 53   , further comprising advancing an interventional or diagnostic catheter over the deflected guidewire from a position relatively proximal to the occlusion, through the channel, and back into the blood vessel lumen.  
     
     
         58 . A method as recited in    claim 53   , further comprising imaging the occlusion and blood vessel lumen to identify their relative location to the guidewire.  
     
     
         59 . A method as recited in    claim 58   , wherein the blood vessel is an artery and the imaging step comprises imaging from a position in a vein adjacent to the artery.  
     
     
         60 . A method as recited in    claim 53   , wherein the distal tip of the guidewire is deflected by providing the guidewire tip with a resilient curved end, and distally advancing the guidewire from a constraining lumen into the blood vessel lumen.