METHOD AND APPARATUS FOR OCCLUSION REMOVAL

• US 20140343585A1
• Filed: 01/17/2013
• Published: 11/20/2014
• Est. Priority Date: 01/17/2012
• Status: Active Grant

• Current Assignee: Perflow Medical Ltd.
• Original Assignee: Perflow Medical Ltd.
• Inventors: Ferrera, David, Rapaport, Avraham, Cibulski, Gilad, Reiter, Allon
• Granted Patent: US 10,383,751 B2
• Time in Patent Office: Days
• US Class Current: 606/159
• CPC Class Codes: A61B 17/12118 for positioning in conjunction with a stent
• CPC Class Codes: A61B 17/1214 Coils or wires
• CPC Class Codes: A61B 17/221 Gripping devices in the form of loops or baskets for gripping calculi or similar types of obstructions surgical snare instruments A61B17/32056
• CPC Class Codes: A61B 17/320725 with radially expandable cutting or abrading elements A61B17/32075 takes precedence
• CPC Class Codes: A61B 2017/22034 for gripping the obstruction or the tissue part from inside
• CPC Class Codes: A61B 2017/32096 for slowly cutting through tissue, e.g. stent like temporary implants having sharp edges
• CPC Class Codes: A61F 2/90 characterised by a net-like or mesh-like structure
• CPC Class Codes: A61F 2/966 with relative longitudinal movement between outer sleeve and prosthesis, e.g. using a push rod
• CPC Class Codes: A61F 2002/823 Stents, different from stent-grafts, adapted to cover an aneurysm
• CPC Class Codes: A61F 2250/0098 radio-opaque, e.g. radio-opaque markers

Abstract

A system for removing a thrombus. The system includes an expandable device that maintains axially fixed engagement with the thrombus. The expandable device applies a first force to the thrombus according to surrounding vessel size. The expandable device applies a second force to the thrombus according to an increased vessel size to maintain axially fixed engagement.

Claims

1-48. -48. (canceled)

49. A device for compressing and removing a thrombus to increase blood flow through a vessel, the device comprising:

an outer tube having a proximal end and a distal end, the tube sized to be slidably disposed within a microcatheter, the tube having an expandable member adjacent the distal end;

a push/pull wire slidably disposed within the outer tube, the wire having a proximal end and a distal end, the wire configured to be actuated from outside the body, the wire coupled to the expandable member at the distal end of the expandable member;

wherein the expandable member is configured to be increased in diameter to a first larger diameter and exert a radial force sufficient to axially fixedly engage the expandable member to the thrombus by compression of the thrombus against a vessel wall, when an axial force component is applied to the proximal end of the wire by pulling the wire, axially displacing the wire with respect to the tube.

50. The device according to claim 49, wherein the axial force component is provided by a spring located at a proximal end of the wire and coupled to the wire.

51. The device according to claim 49, wherein the expandable member is configured to be increased in diameter from a natural state diameter.

52. The device of claim 49, wherein the expandable member is configured to be decreased in diameter when an axial force component is applied to the proximal end of the wire by pushing the wire.

53. The device of claim 49, wherein the expandable member comprises a plurality of wires configured to divergently compress a thrombus within a vessel by application of a first engagement force to maximally compressed thrombus portions in contact with the wires, wherein the first engagement force comprises the radial force component acting at the maximally compressed thrombus portions, and wherein during retraction the wires further apply an axial force component, and wherein the radial force component and axial force component together comprise a first moving engagement force.

54. The device of claim 53, wherein the expandable member expands to non-uniformly compress the thrombus, in a configuration in which less-compressed thrombus portions between maximally compressed thrombus portions in contact with the wires arc inward toward to a center axis of the vessel according to a slope angle, and wherein the expandable member is further configured to expand to a second diameter that is larger than the first diameter in order to maintain or increase the slope angle.

55. The device of claim 54, wherein the expandable member is configured to expand to approximately 6 mm in diameter in a maximally expanded state.

56. The device of claim 54, wherein the wires are configured to not cut into the thrombus upon expansion, thereby maintaining or increasing the slope angles during expansion of the expandable member.

57. The device of claim 54, wherein in a natural state the expandable member has a continuously curved profile formed between proximal and distal ends.

58. The device of claim 57, wherein a total of 8 wires are interwoven to form the expandable member, and wherein axial distance between the crossed wires longitudinally is approximately 3.5 mm when the expandable member is expanded to 2 mm in diameter, and wherein axial distance between the crossed wires longitudinally is approximately 2.4 mm when the expandable member is expanded to 4 mm in diameter.

59. The device of claim 57, wherein a total of 16 wires are interwoven to form the expandable member, and wherein axial distance between the crossed wires longitudinally is approximately 1.7 mm when the expandable member is expanded to 2 mm in diameter, and wherein axial distance between the crossed wires longitudinally is approximately 1.2 mm when the expandable member is expanded to 4 mm in diameter.

60. The device of claim 57, wherein a total of 24 wires are interwoven to form the expandable member, and wherein axial distance between the crossed wires longitudinally is approximately 1.1 mm when the expandable member is expanded to 2 mm in diameter, and wherein axial distance between the crossed wires longitudinally is approximately 0.8 mm when the expandable member is expanded to 4 mm in diameter.

61. The device of claim 57, wherein pull wire actuation distance to expandable member diameter ratio ranges from approximately 0.4 at the first diameter to 2.8 at a maximal diameter.

62. The device of claim 53, wherein the axial force and the radial force represent a linear relationship, the radial force component comprising a majority of the first moving engagement force.

63. The device of claim 53, wherein the axial force and the radial force represent a one-to-one correspondence provided by the equation:

64. The device of claim 51, wherein wires of the expandable member are coiled and interwoven, and are configured to expand to approximately ⅓

to ½

of the vessel diameter in the natural state diameter.

65. The device of claim 50, wherein the spring provides, by pre-loading the spring, several spring vs. force positions in which a radial force applied by the expandable member on the thrombus is adjusted.

66. The device of claim 49, wherein an amount of radial force exerted by the expandable member is increased or maintained as the vessel diameter increases in size to maintain the engagement with the thrombus.

67. The device of claim 49, wherein the radial force is a constant force.

68. The device of claim 49, wherein the radial force is a non-constant force.

69. The device of claim 49, wherein the expandable member is configured to be decreased in diameter when an axial force component is applied to the proximal end of the tube by pulling the tube.

70. The device of claim 49, wherein a displacement sensor is mounted between said outer tube and said wire.

71. The device of claim 49, wherein a stopper in the form of a tube is configured on said wire, said stopper limiting movement of said wire to limit expansion of said expandable member to a predefined diameter.

72. The device of claim 49, wherein a clutch is located between said outer tube and said wire.

73. The device of claim 49, wherein a distal end of the expandable member is configured to pierce the thrombus.

74. A catheter system for removing a thrombus from a blood vessel of a patient, comprising:

a microcatheter having a proximal end and a distal end with a lumen therebetween;

an outer tube having a proximal end and a distal end;

an expandable member disposed near the distal end of the outer tube, the distal end of the outer tube slidably receivable within the lumen of the microcatheter so that the expandable member is releasable distally from the microcatheter within the vessel; and

a push/pull wire slidably disposed within the outer tube, the wire configured to be actuated from outside the body, the wire coupled to the expandable member at the distal end;

wherein the expandable member is configured to be increased in diameter to a first larger diameter and exert a radial force sufficient to axially fixedly engage the expandable member to the thrombus by compression of the thrombus against a vessel wall, when an axial force component is applied to the proximal end of the wire by pulling the wire.

75. The catheter system according to claim 74, wherein said wire is axially displaceable with respect to said outer tube.

76. A method for removing a thrombus, the method comprising:

actuating, from outside the body, an elongate device to expand an expandable member coupled to the elongate device to a first configuration having a first nominal diameter to apply a first engagement force against the thrombus such that the expandable member axially fixedly engages the thrombus by compression of the thrombus against a vessel wall;

retracting the expandable member while the expandable member remains axially fixedly engaged with the thrombus, causing the thrombus to retract;

actuating the elongate device to expand the expandable member to a second configuration having a second nominal diameter that is greater than the first nominal diameter to apply a second engagement force against the thrombus to sufficiently maintain the fixed engagement with the expandable member to continue retracting the thrombus through a vessel portion of greater diameter, reducing a risk of losing the thrombus.

77. The method of claim 76, wherein the expandable member is advanced into the vessel by a catheter, the catheter advanced to a position proximal to the thrombus occluding a distal vessel position.

78. The method of claim 76, wherein the catheter is advanced over a pre-positioned guidewire, and wherein the guidewire is subsequently withdrawn while the catheter is maintained in position.

79. The method of claim 77, wherein the expandable member is advanced distally of the catheter, and the thrombus is pierced with the expandable member such that at least a portion of the expandable member is positioned within the thrombus.

80. The method of claim 79, wherein the expandable member is maintained in a non-expanded configuration within the thrombus before actuating to the first configuration.

81. The method of claim 76, further comprising actuating the elongate device to expand the expandable member to a third configuration having a third nominal diameter that is greater than the second nominal diameter to apply a third engagement force against the thrombus such that axially fixed engagement with the thrombus is sufficiently maintained to continue retracting the thrombus.

82. The method of claim 76, wherein the first engagement force is less than a desired maximum vessel wall engagement force, and wherein the expandable member in the second configuration is configured so as to, if compressed to the first diameter, exceed the desired maximum engagement force such that delaying actuating of the elongate device from the first configuration to the second configuration until after the elongate device is retracted proximally inhibits exceeding of the desired maximum engagement force against the vessel wall.

83. The method of claim 76, wherein actuating of the elongate device from the first configuration to the second configuration is performed in response to the expandable member being adjacent a bend in the vessel and so as to inhibit loss of axially fixed engagement of the expandable member with the thrombus being induced by the bend.

84. The method of claim 76, further comprising retracting the expandable member and the thrombus proximally from the vessel into a lumen of a capture catheter, and actuating the elongate device while retracting the thrombus into the capture catheter.

85. The method of claim 84, wherein the capture catheter is affixed within the vessel by expanding a toroidal balloon of the capture catheter.

86. The method of claim 76, wherein actuating the elongate device comprises pulling a wire coupled to braided coiled wires of the expandable member such that the braided coiled wires axially compress.

87. The method of claim 76, wherein the elongated device is actuated a plurality of times during retraction.

88. The method of claim 76, wherein during said expanding, wires of said expandable member are configured not to cut into the thrombus.