Intravascular devices, systems, and methods for the controlled dissection of body lumens

Abstract

Devices, systems, and methods for treating damaged or diseased valves are disclosed. A representative embodiment includes an elongated shaft having a longitudinal axis, a proximal portion, and a distal portion, and a dissection arm at the distal portion. The dissection arm can have a longitudinal axis and be moveable between a low-profile state and a deployed state. In the deployed state, a portion of the arm can flex outwardly away from the longitudinal axis of the shaft. The arm is configured to be deployed within a space within a vessel wall such that, as the arm moves from the low-profile state to the deployed state, the arm pushes against vessel wall tissue at a periphery of the space, thereby separating tissue at the periphery to form a dissection pocket having a predetermined shape.

I/We claim: 
     
         1 . A method for separating tissue within a wall of a blood vessel, the method comprising:
 delivering a distal portion of a first elongated shaft to a treatment site within the blood vessel;   advancing the distal portion through an opening at an interior surface of a wall of the blood vessel to a space within the wall, wherein the distal portion has a diameter of at most 0.150 inch for gaining access into the space within the wall;   axially moving a second elongated shaft, relative to the first elongated shaft to cause a dissection arm at the distal portion of the first elongated shaft to move from a low-profile state to a deployed state via such that—
 in the deployed state, a portion of the dissection arm flexes outwardly away from a longitudinal axis of the first elongated shaft, and 
 as the dissection arm moves from the low-profile state to the deployed state, the dissection arm pushes against vessel wall tissue at a periphery of the space, thereby separating tissue at the periphery to form a dissection pocket having a predetermined shape; and 
   cutting, via a cutting element positioned along at least a portion of the dissection arm, the vessel wall tissue adjacent to the opening to widen the opening.   
     
     
         2 . The method of  claim 1 , further comprising moving the second elongated shaft over a guide member for delivery of the distal portion of the first elongated shaft into the space within the wall of the blood vessel. 
     
     
         3 . The method of  claim 1 , further comprising:
 creating the opening at the interior surface of the wall of the blood vessel with a needle; and   extending the second elongated shaft over the needle for delivery of the distal portion of the first elongated shaft into the space within the wall of the blood vessel.   
     
     
         4 . The method of  claim 1  wherein delivering the distal portion of the first elongated shaft to the treatment site comprises intravascularly delivery the distal portion of the first elongated shaft to the treatment site. 
     
     
         5 . The method of  claim 1  wherein, when the dissection arm is in the deployed state, the cutting element has a sharp edge facing distally. 
     
     
         6 . The method of  claim 1  wherein, when the dissection arm is in the deployed state, the cutting element has a sharp edge facing proximally. 
     
     
         7 . The method of  claim 1  wherein the dissection arm is a first dissection arm and the cutting element is a first cutting element, and wherein:
 axially moving the second elongated shaft relative to the first elongated shaft causes the first dissection arm and a second dissection arm to move from the low-profile state to the deployed state via such that, in the deployed state, portions of the first and second dissection arms flex outwardly away from the longitudinal axis of the first elongated shaft; and 
 cutting further comprises cutting the vessel wall tissue adjacent to the opening with the first cutting element and a second cutting element. 
 
     
     
         8 . The method of  claim 1  wherein the distal portion of the first elongated shaft has a maximum diameter of 0.099 inch. 
     
     
         9 . The method of  claim 1 , further comprising:
 moving a tensioning arm coupled to the distal portion of the first elongated shaft from a low-profile delivery state to a deployed state in which the tensioning arm flexes outwardly away from the longitudinal axis of the first elongated shaft, wherein at least a portion of the dissection arm and at least a portion of the tensioning arm extend along a longitudinal segment of the distal portion.   
     
     
         10 . The method of  claim 1 , further comprising delivering a focused fluid flow through a needle to create the space within the wall of the blood vessel. 
     
     
         11 . A method for separating tissue within a wall of a blood vessel, the method comprising:
 delivering a distal portion of an elongated shaft to a treatment site within the blood vessel;   advancing the distal portion through an opening at an interior surface of a wall of the blood vessel to a space within the wall, wherein the distal portion has a diameter of at most 0.150 inch for gaining access into the space within the wall;   axially moving an elongated member relative to the elongated shaft to cause a dissection arm at the distal portion of the elongated shaft to move from a low-profile state to a deployed state via such that—
 in the low-profile state, a longitudinal axis of the dissection arm is parallel to a longitudinal axis of the elongated shaft, 
 in the deployed state, a portion of the dissection arm flexes outwardly away from the longitudinal axis of the elongated shaft, and 
 as the dissection arm moves from the low-profile state to the deployed state, the dissection arm pushes against vessel wall tissue at a periphery of the space, thereby separating tissue at the periphery to form a dissection pocket having a predetermined shape; 
   moving a tensioning arm at the distal portion of the elongated shaft from a low-profile state and a deployed state in which the tensioning arm flexes outwardly away from the longitudinal axis of the elongated shaft to create tension in the dissection pocket generally transverse to a plane of dissection; and   cutting vessel wall tissue adjacent the opening to widen the opening using a cutting element on the dissection arm.   
     
     
         12 . The method of  claim 11 , further comprising advancing the elongated member over a guide member for delivery of the distal portion of the elongated shaft to the treatment site. 
     
     
         13 . The method of  claim 11 , further comprising:
 creating the opening at the interior surface of the wall of the blood vessel with a needle; and   extending the elongated member over the needle for delivery of the distal portion of the elongated shaft into the space within the wall of the blood vessel.   
     
     
         14 . The method of  claim 11  wherein cutting the vessel wall tissue adjacent the opening comprises moving the dissection arm in a proximal direction such that the cutting element, facing in the proximal direction, widens the opening. 
     
     
         15 . The method of  claim 11  wherein at least a portion of the dissection arm and at least a portion of the tensioning arm extend along a longitudinal segment of the distal portion. 
     
     
         16 . The method of  claim 11  wherein:
 axially moving the elongated member flexes the dissection arm outwardly within a first plane; and 
 moving the tensioning arm causes the tensioning arm to flex outwardly within a second plane that is angled relative to the first plane. 
 
     
     
         17 . The method of  claim 11  wherein the dissection arm is a first dissection arm, and wherein axially moving the elongated member causes the first dissection arm and a second dissection arm to move to the deployed state such that an outline of the deployed first and second dissection defines the predetermined shape of the dissection pocket. 
     
     
         18 . The method of  claim 11  wherein axially moving the elongated member causes a first segment of the dissection arm and a second segment of the dissection arm to flex outwardly away from the longitudinal axis of the elongated shaft and bend at a flexible joint between the first and second segments. 
     
     
         19 . The method of  claim 11  wherein:
 axially moving the elongated member causes a first, second, and third segments of the dissection arm to flex outwardly away from the longitudinal axis of the elongated shaft and bend at a first flexible joint between the first and second segments and a second flexible joint between the second and third segments; and 
 cutting the vessel wall tissue comprises cutting the vessel wall tissue with the cutting element extending along at least a portion of the third segment. 
 
     
     
         20 . The method of  claim 11 , further comprising delivering a focused fluid flow through a needle to create the space within the wall of the blood vessel. 
     
     
         21 . A device for separating tissue within a wall of a blood vessel, the device comprising:
 a first elongated shaft having a longitudinal axis, a proximal portion and a distal portion, wherein the distal portion is configured to be advanced through an opening at an interior surface of a wall of the blood vessel to a space within the wall, wherein the distal portion has a diameter of at most 0.150 inch for gaining access into the space within the wall;   a second elongated shaft positioned within the first elongated shaft, wherein the second elongated shaft includes a lumen;   a dissection arm at the distal portion of the first elongated shaft, the dissection arm having a longitudinal axis and moveable between a low-profile state and a deployed state via axial movement of the second elongated shaft relative to the first elongated shaft, and wherein—
 in the deployed state, a portion of the dissection arm flexes outwardly away from the longitudinal axis of the first elongated shaft, and 
 the dissection arm is configured to be deployed within the space such that, as the dissection arm moves from the low-profile state to the deployed state, the dissection arm pushes against vessel wall tissue at a periphery of the space, thereby separating tissue at the periphery to form a dissection pocket having a predetermined shape; and 
   a cutting element positioned along at least a portion of the dissection arm and configured to cut the vessel wall tissue adjacent the opening to widen the opening.   
     
     
         22 . The device of  claim 21  wherein the cutting element has a sharp edge, and wherein, in the deployed state, the sharp edge faces proximally. 
     
     
         23 . The device of  claim 21  wherein the dissection arm is a first dissection arm, the cutting element is a first cutting element, and the device includes a second dissection arm and a second cutting element, and wherein the second cutting element is positioned along at least a portion of the second dissection arm. 
     
     
         24 . The device of  claim 21 , further comprising a tensioning arm coupled to the distal portion of the elongated shaft, the tensioning arm having a low-profile state and a deployed state in which the tensioning arm flexes outwardly away from the longitudinal axis of the first elongated shaft, wherein at least a portion of the dissection arm and at least a portion of the tensioning arm extend along a longitudinal segment of the distal portion.