Rotational atherectomy device with radially expandable prime mover coupling

• US 6,129,734 A
• Filed: 10/27/1997
• Issued: 10/10/2000
• Est. Priority Date: 01/21/1997
• Status: Expired due to Term

• Current Assignee: Cardiovascular Systems Incorporated (Boston Scientific Corporation)
• Original Assignee: Shturman Cardiology Systems, Inc.
• Inventors: Volkov, Leonid, Shturman, Leonid
• Primary Examiner(s): Dawson, Glenn K.
• Application Number:
  US08/957,942
• Time in Patent Office: 1,079 Days
• Field of Search: 606/1, 606/159, 606/167, 606/170, 606/171, 606/184, 606/185, 606/180, 604/19, 604/22
• US Class Current: 606/159
• CPC Class Codes: A61B 17/320758 with a rotating cutting instrument, e.g. motor driven A61B17/320725, A61B17/32075 and A61B17/320783 take precedence; for removing intra-ocular material A61F9/00763; endoscopic rotatable cutting instruments A61B17/32002
• CPC Class Codes: A61B 2017/0046 with a releasable handle; with handle and operating part separable for prosthetic joint-implanting tools A61F2/4603
• CPC Class Codes: A61B 2017/00477 Coupling A61B2017/0046 takes precedence
• CPC Class Codes: A61B 2017/00685 Archimedes screw
• CPC Class Codes: A61B 2017/00867 shape memory effect for prostheses A61F2210/0014
• CPC Class Codes: A61B 2017/22049 Means for locking the guide wire in the catheter
• CPC Class Codes: A61B 2017/22075 with motorized advancing or retracting means
• CPC Class Codes: F16D 43/14 with centrifugal masses actuating the clutching members directly in a direction which has at least a radial component; with centrifugal masses themselves being the clutching members

Abstract

A rotatable atherectomy device having an exchangeable drive shaft cartridge and a rotatable prime mover coupling. The cartridge has a rotatable drive shaft socket carried by a carriage. The coupling radially expands during rotation such that it interlocks with the socket to drive a tissue removal implement on the end of a drive shaft attached to the cartridge. Upon slow or no rotation of the socket, the coupling disengages from the socket to allow for exchange of the cartridge.

Claims

1. A rotational atherectomy device comprising:

a. an exchangeable drive shaft cartridge comprising a rotatable drive shaft socket carried by a drive shaft carriage;

a longitudinally extendable tube extending distally from the drive shaft carriage;

an elongated catheter having a proximal end portion which is operatively connected to a distal end portion of the longitudinally extendable tube; and

a rotatable flexible drive shaft having proximal, intermediate and distal portions, the proximal portion being attached to the drive shaft socket, the intermediate portion being disposed primarily within the tube and the catheter, and the distal portion extending distally from the catheter and having a tissue removal implement;

b. a rotatable, radially expandable prime mover coupling connected to a prime mover for rotation therewith, the prime mover being carried by a prime mover carriage and the prime mover coupling including a radially expandable portion;

the drive shaft socket being sized to receive a length of the radially expandable portion of the prime mover coupling therein such that the radially expandable portion of the prime mover coupling does not effectively engage an interior surface of the drive shaft socket when the coupling is not rotating, but the radially expandable portion of the prime mover coupling radially expands to effectively engage the socket upon sufficiently rapid rotation of the prime mover, causing the socket and the drive shaft to rotate together with the prime mover coupling and the prime mover,

whereby when the prime mover is not rotating, the drive shaft is disconnected from the prime mover, thereby permitting the exchangeable drive shaft cartridge to be replaced by another exchangeable drive shaft cartridge.

2. The rotational atherectomy device of claim 1 wherein the radially expandable portion of the coupling resiliently regains a radially reduced dimension when it is not rotated, thereby disconnecting the drive shaft from the prime mover.

3. The rotational atherectomy device of claim 1 wherein the radially expandable portion of the prime mover coupling does not contact the interior surface of the drive shaft socket when the coupling is not rotating.

4. The rotational atherectomy device of claim 1 wherein the drive shaft socket includes a proximally extending engagement ring defining an interior engagement surface of the socket, the radially expandable portion of the coupling being adapted to radially expand into frictional engagement with the interior engagement surface of the socket in response to rotation of the prime mover shaft.

5. The rotational atherectomy device of claim 1 wherein the prime mover coupling further comprises a coupling base and the radially expandable portion of the coupling comprises at least two flexible pins, each pin being anchored adjacent one end thereof to the coupling base and having another end which is free to deflect radially outwardly to engage the drive shaft socket when the prime mover is rotated.

6. The rotational atherectomy device of claim 5 wherein the drive shaft socket includes a proximally extending engagement ring defining an interior engagement surface of the socket, the pins being adapted to deflect radially outwardly into frictional engagement with the interior engagement surface of the socket in response to rotation of the prime mover.

7. The rotational atherectomy device of claim 5 wherein the drive shaft socket includes a proximally extending engagement ring defining a generally cylindrical interior engagement surface of the socket, the pins being adapted to deflect radially outwardly into frictional engagement with the interior engagement surface of the socket in response to rotation of the prime mover.

8. The rotational atherectomy device of claim 5 wherein said pins are spaced equiangularly about an axis of the coupling base.

9. The rotational atherectomy device of claim 5 wherein there are at least six of said pins.

10. The rotational atherectomy device of claim 5 wherein each of the pins is formed of a superelastic material.

11. The rotational atherectomy device of claim 10 wherein said superelastic material is nitinol.

12. The rotational atherectomy device of claim 5 wherein an intermediate portion of each pin is received in a counterbore in the coupling base, each counterbore having an inner diameter greater than the outer diameter of the pin received therein.

13. The rotational atherectomy device of claim 5 wherein the coupling base includes at least one abutment spaced radially outwardly from each pin when the coupling base is not rotated and limiting outward deflection of an intermediate point along the length of the pin when the prime mover is rotated.

14. The rotational atherectomy device of claim 13 wherein the abutment comprises a single annular wall extending longitudinally from the coupling base and spaced radially outwardly from each of the pins when the coupling base is not rotated.

15. The rotational atherectomy device of claim 5 wherein the pins are integrally formed with the coupling base.

16. The rotational atherectomy device of claim 5 wherein the coupling base is integrally formed with a shaft of the prime mover.

17. The rotational atherectomy device of claim 5 wherein the pins, the coupling base and a shaft of the prime mover are all integrally formed.

18. The rotational atherectomy device of claim 5 wherein the prime mover carriage further comprises a coupling shield which restricts outward deflection of the free ends of the pins upon rotation of the prime mover when the free ends of the pins are not properly received within the drive shaft socket.

19. The rotational atherectomy device of claim 18 wherein the coupling shield is carried by the prime mover coupling and can be moved away from the free ends of the pins to permit the pins to be properly received within the socket so the pins can engage the drive shaft socket upon rotation of the prime mover.

20. The rotational atherectomy device of claim 1 wherein the prime mover coupling further comprises a coupling base and the radially expandable portion of the coupling comprises at least two flexible pins, each pin being anchored adjacent a proximal end to the coupling base and having a distal end which is free to deflect radially outwardly to engage an interior engagement surface of the drive shaft socket when the prime mover is rotated.

21. The rotational atherectomy device of claim 20 wherein the socket has a proximal end portion defining an interior surface, the pins being adapted to deflect radially outwardly into frictional engagement with the interior engagement surface of the socket in response to rotation of the prime mover shaft.

22. The rotational atherectomy device of claim 20 wherein said pins are spaced equiangularly about an axis of the coupling base.

23. The rotational atherectomy device of claim 20 wherein there are at least six of said pins.

24. The rotational atherectomy device of claim 20 wherein each of the pins is formed of a superelastic material.

25. The rotational atherectomy device of claim 24 wherein said superelastic material is nitinol.

26. The rotational atherectomy device of claim 20 wherein an intermediate portion of each pin is received in a counterbore in the coupling base, each counterbore having an inner diameter greater than the outer diameter of the pin received therein.

27. The rotational atherectomy device of claim 18 wherein the coupling base includes at least one abutment spaced radially outwardly from each pin when the coupling base is not rotated and limiting outward deflection of an intermediate point along the length of the pin when the prime mover is rotated.

28. The rotational atherectomy device of claim 27 wherein the abutment comprises a single annular wall extending longitudinally distally from the coupling base and spaced radially outwardly from each of the pins when the coupling base is not rotated.

29. The rotational atherectomy device of claim 20 wherein the pins are integrally formed with the coupling base.

30. The rotational atherectomy device of claim 20 wherein the coupling base is integrally formed with a shaft of the prime mover.

31. The rotational atherectomy device of claim 20 wherein the pins, the coupling base and a shaft of the prime mover are all integrally formed.

32. The rotational atherectomy device of claim 20 wherein the prime mover carriage further comprises a coupling shield which restricts outward deflection of the distal ends of the pins upon rotation of the prime mover when the distal ends of the pins are not properly received within the drive shaft socket.

33. The rotational atherectomy device of claim 32 wherein the coupling shield is carried by the base of the prime mover coupling and can be moved away from the distal ends of the pins to permit the pins to be properly received within the socket so the pins can engage the drive shaft socket upon rotation of the prime mover.

34. The rotational atherectomy device of claim 1 wherein the radially expandable portion of the prime mover coupling comprises an elastomeric, radially expandable tube, the tube being connected adjacent one end thereof to a prime mover shaft and having another end which is free to expand radially outwardly to engage the interior surface of the drive shaft socket when the prime mover is rotated.

35. The rotational atherectomy device of claim 34 wherein the radially expandable tube is connected to the prime mover shaft adjacent its proximal end and has a distal end which is free to expand radially outwardly.

36. The rotational atherectomy device of claim 35 wherein the tube has distal and intermediate portions which are both free to expand radially outwardly, the distal portion having a greater mass per unit length than the intermediate portion.

37. The rotational atherectomy device of claim 36 wherein the distal portion is thicker than the intermediate portion.

38. The rotational atherectomy device of claim 1 wherein the prime mover coupling further comprises a coupling base and the radially expandable portion of the coupling comprises at least two flyweights carried by the coupling base, each flyweight being free to move radially outwardly to engage an interior engagement surface of the drive shaft socket when the prime mover is rotated.

39. The rotational atherectomy device of claim 38 wherein each flyweight is slidably received in a radially extending bore in the coupling base, the coupling base including a circumferential stop for limiting outward movement of the flyweights.

40. The rotational atherectomy device of claim 38 wherein the interior engagement surface of the socket includes recesses for engaging the flyweights.

41. The rotational atherectomy device of claim 1 wherein the drive shaft carriage and the prime mover carriage are longitudinally moveable with respect to one another from an operational position wherein a length of the radially expandable portion of the prime mover coupling is received within the drive shaft socket to a non-operational position wherein the radially expandable portion of the prime mover coupling is withdrawn from the drive shaft socket.

42. The rotational atherectomy device of claim 41 wherein, in the operational position, the drive shaft carriage and the prime mover carriage are interconnected to move together as a unit to move the drive shaft and its tissue removal implement along a vascular lumen of a patient'"'"'s body.

43. The rotational atherectomy device of claim 42 further comprising fittings associated with the drive shaft carriage and the prime mover carriage, the fittings being designed to fix the relative positions of the drive shaft socket and the prime mover coupling in the operational position.

44. The rotational atherectomy device of claim 43 wherein the fittings are connected to one another at three or more equiangularly spaced positions.

45. The rotational atherectomy device of claim 43 wherein at least one of the fittings is free to rotate with respect to the carriage with which it is associated to facilitate connection of the carriages to one another.

46. The rotational atherectomy device of claim 43 wherein the fittings comprise mating components of a bayonet joint.

47. The rotational atherectomy device of claim 1 wherein the drive shaft carriage and the prime mover carriage are provided with mating components of a bayonet joint to connect the carriages to one another.

48. The rotational atherectomy device of claim 47 wherein the mating components comprise pins and slots, the pins being carried by one of the carriages and the slots being formed in a bayonet collar carried by the other carriage.

49. The rotational atherectomy device of claim 48 wherein the bayonet collar is rotatable about the carriage which carries the bayonet collar.

50. The rotational atherectomy device of claim 47 wherein the bayonet joint connects the carriages to one another at three or more equiangularly spaced positions.

51. The rotational atherectomy device of claim 1 wherein the exchangeable drive shaft cartridge further comprises a generally tubular housing carrying the longitudinally extendable tube.

52. The rotational atherectomy device of claim 51 wherein the tubular housing of the drive shaft cartridge has a generally cylindrical outer surface.

53. The rotational atherectomy device of claim 51 wherein the longitudinally extendable tube includes outer and inner telescoping tubes, the outer telescoping tube being connected to the drive shaft carriage and the inner telescoping tube being connected to a distal end piece of the tubular housing.

54. The rotational atherectomy device of claim 53 wherein the outer telescoping tube is slidably received in an elongated annular space defined between an inner surface of the tubular housing and an outer surface of the inner telescoping tube.

55. The rotational atherectomy device of claim 54 wherein the outer telescoping tube is moveable both longitudinally and rotationally with respect to both the tubular housing and the in telescoping tube.

56. The rotational atherectomy device of claim 54 further comprising complementary fittings associated with the tubular housing and the drive shaft carriage for releasably locking the drive shaft carriage to the tubular housing when a majority of the length of the outer telescoping tube is received within the tubular housing of the drive shaft cartridge.

57. The rotational atherectomy device of claim 56 wherein the complementary fittings comprise at least one tab carried by one of the tubular housing and the drive shaft carriage and a flange carried by the other one of the tubular housing and the drive shaft carriage.

58. The rotational atherectomy device of claim 56 wherein the outer telescoping tube is free to rotate with respect to both the tubular housing and the inner telescoping tube when the drive shaft carriage is releasably locked to the tubular housing of the cartridge.

59. The rotational atherectomy device of claim 1 further comprising a handle which carries the prime mover carriage and which is adapted to releasably hold the drive shaft cartridge.

60. The rotational atherectomy device of claim 59 wherein the handle includes at least one clamp for releasably holding a generally tubular housing of the drive shaft cartridge.

61. The rotational atherectomy device of claim 59 wherein the prime mover carriage is longitudinally moveable with respect to the handle.

62. The rotational atherectomy device of claim 59 wherein the drive shaft carriage is longitudinally moveable with respect to the handle when the drive shaft cartridge is releasably held by the handle.

63. The rotational atherectomy device of claim 59 wherein the drive shaft carriage and the prime mover carriage are adapted to be interconnected for movement together as a unit longitudinally with respect to the handle.

64. The rotational atherectomy device of claim 59 wherein the drive shaft carriage and the prime mover carriage are adapted to be interconnected for movement together as a unit both longitudinally and rotationally with respect to the handle.

65. The rotational atherectomy device of claim 59 wherein an axis of the drive shaft carriage is substantially aligned with an axis of the prime mover carriage when the drive shaft cartridge is releasably held by the handle.

66. The rotational atherectomy device of claim 59 wherein the drive shaft carriage and the prime mover carriage are moveable with respect to one another longitudinally along their aligned axes from an operational position wherein a length of the radially expandable portion of the prime mover coupling is received within the drive shaft socket to a non-operational position wherein the radially expandable portion of the prime mover coupling is withdrawn from the drive shaft socket.

67. The rotational atherectomy device of claim 66 wherein the drive shaft carriage and the prime mover carriage are adapted to be interconnected for movement together as a unit longitudinally with respect to the handle along their aligned axes.

68. The rotational atherectomy device of claim 59 wherein the handle comprises a distal portion adapted to releasably hold the drive shaft cartridge, a proximal portion carrying the prime mover carriage, and an elongated rod connecting the distal and proximal portions of the handle to one another.

69. The rotational atherectomy device of claim 68 further comprising a telescoping tube slidably received in the proximal portion of the handle and having a distal end connected to the prime mover carriage.

70. The rotational atherectomy device of claim 69 wherein the elongated rod of the handle extends generally parallel to the telescoping tube connected to the prime mover carriage and is spaced therefrom a distance sufficient to permit both the drive shaft carriage and the prime mover carriage to move parallel to the elongated rod of the handle.

71. The rotational atherectomy device of claim 68 wherein the drive shaft carriage and the prime mover carriage are adapted to be interconnected for movement together as a unit longitudinally with respect to the handle.

72. The rotational atherectomy device of claim 68 wherein the drive shaft carriage and the prime mover carriage are adapted to be interconnected for movement together as a unit both longitudinally and rotationally with respect to the handle.

73. The rotational atherectomy device of claim 68 wherein the distal portion of the handle includes a pair of opposing walls defining a longitudinally extending groove for releasably holding a length of the drive shaft cartridge therein.

74. The rotational atherectomy device of claim 73 further comprising a slot in one of the opposing walls for receiving a flexible fluid supply tubing therein.

75. The rotational atherectomy device of claim 73 wherein the groove has a depth greater than an outer diameter of a tubular housing of the drive shaft cartridge, thereby limiting manual pressure on the tubular housing when a user grasps the handle around the groove.

76. The rotational atherectomy device of claim 73 wherein the distal portion of the handle includes at least one clamp for retaining the drive shaft cartridge in the groove.

77. The rotational atherectomy device of claim 76 wherein the handle includes two clamps, the clamps being spaced from one another longitudinally along the distal portion of the handle.

78. The rotational atherectomy device of claim 76 wherein the clamp is sized to releasably hold a generally tubular housing of the drive shaft cartridge.

79. The rotational atherectomy device of claim 78 wherein the groove in the distal portion of the handle has a depth greater than an outer diameter of the tubular housing of the drive shaft cartridge.

82. The rotational atherectomy device of claim 76 wherein the clamp and the opposing walls defining the groove are all formed as a single component.

83. The rotational atherectomy device of claim 76 wherein the clamp and the distal portion of the handle are formed as a single component.

84. The rotational atherectomy device of claim 76 wherein the clamp, the opposing walls defining the groove and the distal portion of the handle are all formed as a single component.

85. The rotational atherectomy device of claim 76 wherein the clamp includes two opposing sides, one side of the clamp being integrally formed with one of the walls and the other side of the clamp being integrally formed with the other wall.

86. The rotational atherectomy device of claim 76 wherein the distal portion of the handle comprises two laterally opposed mating elements, one of the opposed walls and one side of the clamp being integrally formed with one of the mating elements, the other of the walls and another side of the clamp being integrally formed with another of the mating elements.

89. The rotational atherectomy device of claim 1 further comprising a flexible fluid supply tubing attached to the exchangeable drive shaft cartridge and in fluid communication with a drive shaft lumen of the drive shaft cartridge, the drive shaft lumen being defined by a lumen of the catheter and a lumen of the longitudinally extendable tube.

90. The rotational atherectomy device of claim 89 wherein the drive shaft lumen receives a majority of the length of the drive shaft.

91. The rotational atherectomy device of claim 89 wherein the drive shaft lumen includes a reduced inner diameter segment, the reduced inner diameter segment being positioned proximally of where the fluid supply tubing delivers fluid to the drive shaft lumen, thereby reducing flow of fluid proximally along the drive shaft lumen.

92. The rotational atherectomy device of claim 91 wherein a sufficient clearance exists between the drive shaft and the interior of the reduced inner diameter segment of the drive shaft lumen to permit a restricted flow of fluid proximally along the drive shaft lumen.

93. The rotational atherectomy device of claim 91 wherein a thin-walled tubing extends along a proximal length of an intermediate portion of the drive shaft from a distal end of a tubular shaft of the drive shaft socket to a point located distally of a proximal end of the reduced inner diameter segment of the drive shaft lumen.

94. The rotational atherectomy device of claim 93 wherein the thin-walled tubing extends distally beyond a distal end of the reduced inner diameter segment of the drive shaft lumen.

95. The rotational atherectomy device of claim 93 wherein the thin-walled tubing extends distally beyond the location where the fluid supply tubing delivers fluid to the drive shaft lumen.

96. The rotational atherectomy device of claim 93 wherein the thin-walled tubing extends distally into the proximal end portion of the catheter.

97. The rotational atherectomy device of claim 93 wherein the thin-walled tubing is a heat-shrinkable tubing.

98. The rotational atherectomy device of claim 93 wherein the thin-walled tubing is a heat-shrinkable polyester tubing.

99. The rotational atherectomy device of claim 93 wherein the thin-walled tubing extends for a length not less than about 160 mm.

100. The rotational atherectomy device of claim 89 wherein the fluid supply tubing delivers fluid from a fluid supply external the cartridge.

101. The rotational atherectomy device of claim 89 wherein the fluid supply tubing has two ends, one end being attached to the drive shaft cartridge distally of the drive shaft socket and the other end of the tubing being in fluid communication with an external fluid supply.

102. The rotational atherectomy device of claim 89 wherein the fluid supply tubing is attached to the drive shaft cartridge distally of the drive shaft socket.

103. The rotational atherectomy device of claim 89 wherein the fluid supply tubing is attached to the drive shaft cartridge distally of the drive shaft socket and proximally of the catheter.

104. The rotational atherectomy device of claim 89 wherein the fluid supply tubing is attached to the drive shaft cartridge adjacent a distal end of the longitudinally extendable tube.

105. The rotational atherectomy device of claim 89 wherein the longitudinally extendable tube includes at least two telescoping tubes.

106. The rotational atherectomy device of claim 105 wherein the fluid supply tubing is attached to the drive shaft cartridge distally of at least one of the telescoping tubes.

107. The rotational atherectomy device of claim 105 wherein the fluid supply tubing is attached to the drive shaft cartridge distally of all of the telescoping tubes.

108. The rotational atherectomy device of claim 105 wherein the fluid supply tubing is attached to the drive shaft cartridge distally of at least one of the telescoping tubes and proximally of the catheter.

109. The rotational atherectomy device of claim 105 wherein the fluid supply tubing is attached to the drive shaft cartridge primally of the catheter.

110. The rotational atherectomy device of claim 89 wherein the drive shaft comprises a helically wound coil which defines a guide wire lumen of the drive shaft, fluid supplied to the drive shaft lumen passing between wire turns of the drive shaft into the guide wire lumen.

111. The rotational atherectomy device of claim 110 wherein a generally tubular shaft of the prime mover defines a guide wire lumen which extends proximally from the guide wire lumen of the drive shaft when the radially expandable portion of the prime mover coupling is received in the drive shaft socket.

112. The rotational atherectomy device of claim 111 wherein the guide wire lumen of the drive shaft and the guide wire lumen of the prime mover shaft are aligned and in fluid communication with one another when the radially expandable portion of the prime mover coupling is received in the drive shaft socket, thereby permitting the drive shaft and the prime mover to be advanced together as a unit over the guide wire.

113. The rotational atherectomy device of claim 111 wherein the guide wire lumen of the drive shaft and the guide wire lumen of the prime mover shaft are aligned and in fluid communication with one another when the radially expandable portion of the prime mover coupling is received in the drive shaft socket, thereby permitting the drive shaft and the prime mover to be rotated together as a unit over the guide wire.

114. The rotational atherectomy device of claim 111 wherein the guide wire lumen of the drive shaft and the guide wire lumen of the prime mover shaft are aligned and in fluid communication with one another when the radially expandable portion of the prime mover coupling is received in the drive shaft socket, thereby permitting the drive shaft and the prime mover to be advanced and rotated together as a unit over the guide wire.

115. The rotational atherectomy device of claim 111 wherein the guide wire lumen of the prime mover shaft is in fluid communication with a fluid outlet located adjacent a proximal end of the prime mover shaft.

116. The rotational atherectomy device of claim 111 further comprising a helically wound coil disposed within the guide wire lumen of the prime mover shaft, the coil being rotatable together with the prime mover.

117. The rotational atherectomy device of claim 116 wherein the coil disposed within the prime mover shaft is oriented to urge fluid proximally when the prime mover is rotated.

118. The rotational atherectomy device of claim 111 wherein the drive shaft socket includes a proximally oriented face and a central extension which extends proximally from that face, the guide wire lumen of the prime mover shaft slidably receiving a proximal length of the central extension of the socket when the radially expandable portion of the prime mover coupling is received in the drive shaft socket such that the guide wire lumen of the drive shaft is in fluid communication with the guide wire lumen of the prime mover shaft.

119. The rotational atherectomy device of claim 1 wherein the prime mover coupling includes a dynamic seal for urging fluid away from a bearing supporting a shaft of the prime mover.

120. The rotational atherectomy device of claim 119 wherein the dynamic seal includes a barrier centrifugally urging fluid distally in response to rotation of the prime mover.

121. The rotational atherectomy device of claim 120 wherein the barrier comprises a generally frustoconical flange carried by a proximal portion of the prime mover coupling.

122. The rotational atherectomy device of claim 121 further comprising a plurality of such barriers spaced along the proximal portion of the prime mover coupling.

123. The rotational atherectomy device of claim 1 wherein the prime mover carriage further comprises a coupling shield which restricts radial expansion of the radially expandable portion of the prime mover coupling upon rotation of the prime mover when the radially expandable portion of the prime mover coupling is not properly received within the drive shaft socket.

124. The rotational atherectomy device of claim 123 wherein the coupling shield is carried by the prime mover coupling and can be moved away from a distal end of the coupling to permit the radially expandable portion of the coupling to be properly received within the socket so the radially expandable portion of the coupling can engage the drive shaft socket upon rotation of the prime mover.

125. The rotational atherectomy device of claim 124 wherein the coupling shield is biased toward the distal end of the prime mover coupling.

126. The rotational atherectomy device of claim 124 wherein the coupling shield is carried by a base of the prime mover coupling and is biased toward the distal end of the coupling by a compression spring disposed proximally of the shield around the base of the coupling.

127. The rotational atherectomy device of claim 126 wherein the shield presents a generally annular distal face, the distal face of the shield being sized to abut the drive shaft socket, thereby permitting the drive shaft socket to move the shield away from the distal end of the coupling to permit the radially expandable portion of the coupling to be properly received within the socket.

128. The rotational atherectomy device of claim 127 wherein the shield comprises an annular collar which surrounds a length of the radially expandable portion of the coupling.

129. The rotational atherectomy device of claim 128 wherein the base of the prime mover coupling and the collar are fitted together in a tongue-in-groove relationship to guide the collar generally longitudinally along the coupling base and limit rotation of the collar with respect to the base.

130. The rotational atherectomy device of claim 1 wherein the drive shaft carriage further comprises a bearing which supports the drive shaft socket.

131. The rotational atherectomy device of claim 130 wherein the bearing is a ball bearing.

132. The rotational atherectomy device of claim 1 wherein the longitudinally extendable tube includes at least two telescoping tubes.

133. The rotational atherectomy device of claim 132 wherein one of the telescoping tubes is connected to a distal end piece of a housing of the exchangeable drive shaft cartridge while another of the telescoping tubes carries the drive shaft carriage.

80. The rotational atherectomy device of claim 80 wherein the groove is upwardly open.

81. The rotational atherectomy device of claim 80 wherein the side walls defining the groove are sized to extend above the tubular housing to limit manual pressure on the tubular housing when a user grasps the handle around the groove.

87. The rotational atherectomy device of claim 87 further comprising at least one leg removably interlockable with the handle.

88. The rotational atherectomy device of claim 87 wherein the leg includes a clamp sized and shaped to releasably interlock with the handle.

134. A rotational atherectomy device comprising:

a) an exchangeable drive shaft cartridge comprising a rotatable drive shaft socket carried by a drive shaft carriage;

a catheter; and

a rotatable flexible drive shaft having a proximal, intermediate and distal portions, the proximal portion of the drive shaft being attached to the drive shaft socket, the intermediate portion of the drive shaft being disposed primarily within the catheter, and the distal portion of the drive shaft extending distally from the catheter and having an abrasive tissue removal implement;

b) a rotatable prime mover coupling attached to a shaft of a prime mover for rotation therewith, the prime mover coupling including a radially expandable portion;

the drive shaft socket being sized to receive a length of the radially expandable portion of the coupling therein such that the radially expandable portion of the coupling does not contact an interior of the drive shaft socket when the prime mover coupling is not rotating, but the radially expandable portion of the coupling radially expands into frictional engagement with the socket upon sufficiently rapid rotation of the prime mover, causing the socket and the drive shaft to rotate together with the prime mover coupling and the prime mover,

whereby when the prime mover is not rotating, the drive shaft is disconnected from the prime mover, thereby permitting the exchangeable drive shaft cartridge to be replaced by another exchangeable drive shaft cartridge.

136. The rotational atherectomy device of claim 134 or claim 135 wherein the prime mover and the rotatable prime mover coupling are carried by a prime mover carriage, the prime mover carriage and the drive shaft carriage having mating fittings which permit the carriages to be interconnected so they can be moved together as a unit.

137. The rotational atherectomy device of claim 136 wherein the fittings comprise mating components of a bayonet joint.

146. The rotational atherectomy device of claim 134, claim 135, claim 143 or claim 145 wherein the prime mover coupling comprises a coupling base and at least two flexible pins, each pin being anchored adjacent a proximal end to the coupling base and having a distal end which is free to deflect radially outwardly to engage the interior of the drive shaft socket when the prime mover is rotated.

147. The rotational atherectomy device of claim 146 further comprising a coupling shield carried by the prime mover coupling, the coupling shield restricting outward deflection of the distal ends of the pins upon rotation of the prime mover when the distal ends of the pins are not properly received within the drive shaft socket.

149. The rotational atherectomy device of claim 134, claim 135 or claim 145 further comprising a flexible fluid supply tubing attached to the exchangeable drive shaft cartridge and in fluid communication with a drive shaft lumen of the drive shaft cartridge.

150. The rotational atherectomy device of claim 149 wherein the drive shaft lumen includes a reduced inner diameter segment, the reduced inner diameter segment being positioned proximally of where the fluid supply tubing delivers fluid to the drive shaft lumen, thereby reducing flow of fluid proximally along the drive shaft lumen.

135. A rotational atherectomy device comprising:

a) an exchangeable drive shaft cartridge comprising a rotatable drive shaft socket carried by a drive shaft carriage;

a longitudinally extendable tube extending distally from the drive shaft carriage;

a catheter extending distally from the tube; and

a flexible drive shaft having a lumen for receiving a guidewire around which the drive shaft may rotate, the drive shaft having proximal, intermediate and distal portions, the proximal portion being attached to the drive shaft socket, the intermediate portion being disposed primarily within the tube and the catheter, and the distal portion extending distally from the catheter and having an abrasive tissue removal implement;

b) a rotatable prime mover coupling attached to a shaft of a prime mover for rotation therewith, the prime mover coupling including a radially expandable portion;

the drive shaft socket being sized to receive a length of the radially expandable portion of the coupling therein such that the radially expandable portion of the coupling does not contact an interior of the drive shaft socket when the prime mover coupling is not rotating, but the radially expandable portion of the coupling radially expands into frictional engagement with the socket upon sufficiently rapid rotation of the prime mover, causing the socket and the drive shaft to rotate together with the prime mover coupling and the prime mover,

whereby when the prime mover is not rotating, the drive shaft is disconnected from the prime mover, thereby permitting the exchangeable drive shaft cartridge to be replaced by another exchangeable drive shaft cartridge.

138. A rotational atherectomy device comprising:

a) an exchangeable drive shaft cartridge comprising a rotatable drive shaft socket carried by a drive shaft carriage;

a longitudinally extendable tube extending distally from the drive shaft carriage;

a catheter extending distally from the tube; and

a rotatable flexible drive shaft having proximal, intermediate and distal portions, the proximal portion being attached to the drive shaft socket, the intermediate portion being disposed primarily within the tube and the catheter, and the distal portion extending distally from the catheter and having an abrasive tissue removal implement;

b) a flexible fluid supply tubing connected to the drive shaft cartridge distally of the drive shaft socket;

c) a rotatable prime mover coupling carried by a prime mover carriage and connected to a prime mover for rotation therewith, the prime mover coupling including a coupling base and at least two flexible pins, each pin being formed of a superelastic material and connected adjacent a proximal end to the coupling base and having a distal end portion which is free to deflect radially outwardly into frictional engagement with an interior surface of the drive shaft socket when the prime mover is rotated;

d) the drive shaft carriage and the prime mover carriage including mating fittings which permit the carriages to be interconnected to move together as a unit;

the drive shaft socket being sized to receive the distal end portions of the pins of the prime mover coupling therein such that the pins do not contact the interior surface of the drive shaft socket when the coupling is not rotating, but the distal end portions of the pins deflect into frictional engagement with the socket upon sufficiently rapid rotation of the prime mover, causing the socket and the drive shaft to rotate together with the prime mover coupling and the prime mover,

whereby when the prime mover is not rotating, the drive shaft is disconnected from the prime mover, thereby permitting the exchangeable drive shaft cartridge to be replaced by another exchangeable drive shaft cartridge.

148. The rotational atherectomy device of claim 138, claim 139, claim 140, claim 141, claim 143, or claim 145 further comprising a handle which includes a distal portion adapted to releasably hold the drive shaft cartridge, a proximal portion carrying the prime mover carriage, and an elongated rod connecting the distal and proximal portions of the handle to one another.

139. A rotational atherectomy device comprising:

a) an exchangeable drive shaft cartridge comprising a rotatable drive shaft socket carried by a drive shaft carriage;

a longitudinally extendable tube extending distally from the drive shaft carriage;

a catheter extending distally from the tube; and

a rotatable flexible drive shaft having proximal, intermediate and distal portions, the proximal portion being attached to the drive shaft socket, the intermediate portion being disposed primarily within the tube and the catheter, and the distal portion extending distally from the catheter and having an abrasive tissue removal implement;

b) a flexible fluid supply tubing connected to the drive shaft cartridge distally of the drive shaft socket;

c) a rotatable prime mover coupling carried by a prime mover carriage and connected to a prime mover for rotation therewith, the prime mover coupling including a coupling base and at least six flexible pins, each pin being formed of a superelastic material and connected adjacent a proximal end to the coupling base and having a distal end portion which is free to deflect radially outwardly into frictional engagement with an interior surface of the drive shaft socket when the prime mover is rotated;

d) the drive shaft carriage and the prime mover carriage including mating fittings which permit the carriages to be interconnected to move together as a unit;

the drive shaft socket being sized to receive the distal end portions of the pins of the prime mover coupling therein such that the pins do not contact the interior surface of the drive shaft socket when the coupling is not rotating, but the distal end portions of the pins deflect into frictional engagement with the socket upon sufficiently rapid rotation of the prime mover, causing the socket and the drive shaft to rotate together with the prime mover coupling and the prime mover,

whereby when the prime mover is not rotating, the drive shaft is disconnected from the prime mover, thereby permitting the exchangeable drive shaft cartridge to be replaced by another exchangeable drive shaft cartridge.

140. A rotational atherectomy device comprising:

a) an exchangeable drive shaft cartridge comprising a rotatable drive shaft socket carried by a drive shaft carriage;

a longitudinally extendable tube extending distally from the drive shaft carriage;

a catheter extending distally from the tube; and

a rotatable flexible drive shaft having proximal, intermediate and distal portions, the proximal portion being attached to the drive shaft socket, the intermediate portion being disposed primarily within the tube and the catheter, and the distal portion extending distally from the catheter and having an abrasive tissue removal implement;

b) a flexible fluid supply tubing connected to the drive shaft cartridge distally of the drive shaft socket;

c) a rotatable prime mover coupling carried by a prime mover carriage and connected to a prime mover for rotation therewith, the prime mover coupling including a coupling base and at least two flexible pins, each pin being formed of a superelastic material and connected adjacent a proximal end to the coupling base and having a distal end portion which is free to deflect radially outwardly into frictional engagement with an interior surface of the drive shaft socket when the prime mover is rotated;

d) the drive shaft carriage and the prime mover carriage including mating components of a bayonet joint to connect the carriages to one another to permit the carriages to move together as a unit;

the drive shaft socket being sized to receive the distal end portions of the pins of the prime mover coupling therein such that the pins do not contact the interior surface of the drive shaft socket when the coupling is not rotating, but the distal end portions of the pins deflect into frictional engagement with the socket upon sufficiently rapid rotation of the prime mover, causing the socket and the drive shaft to rotate together with the prime mover coupling and the prime mover,

whereby when the prime mover is not rotating, the drive shaft is disconnected from the prime mover, thereby permitting the exchangeable drive shaft cartridge to be replaced by another exchangeable drive shaft cartridge.

141. A rotational atherectomy device comprising:

a) an exchangeable drive shaft cartridge comprising a rotatable drive shaft socket carried by a drive shaft carriage;

a longitudinally extendable tube extending distally from the drive shaft carriage;

a catheter extending distally from the tube; and

a rotatable flexible drive shaft having proximal, intermediate and distal portions, the proximal portion being attached to the drive shaft socket, the intermediate portion being disposed primarily within the tube and the catheter, and the distal portion extending distally from the catheter and having an abrasive tissue removal implement;

b) a flexible fluid supply tubing connected to the drive shaft cartridge distally of the drive shaft socket;

c) a rotatable prime mover coupling carried by a prime mover carriage and connected to a prime mover for rotation therewith, the prime mover coupling including a coupling base and at least six flexible pins, each pin being formed of a superelastic material and connected adjacent a proximal end to the coupling base and having a distal end portion which is free to deflect radially outwardly into frictional engagement with an interior surface of the drive shaft socket when the prime mover is rotated;

d) the drive shaft carriage and the prime mover carriage including mating components of a bayonet joint to connect the carriages to one another to permit the carriages to move together as a unit;

the drive shaft socket being sized to receive the distal end portions of the pins of the prime mover coupling therein such that the pins do not contact the interior surface of the drive shaft socket when the coupling is not rotating, but the distal end portions of the pins deflect into frictional engagement with the socket upon sufficiently rapid rotation of the prime mover, causing the socket and the drive shaft to rotate together with the prime mover coupling and the prime mover,

whereby when the prime mover is not rotating, the drive shaft is disconnected from the prime mover, thereby permitting the exchangeable drive shaft cartridge to be replaced by another exchangeable drive shaft cartridge.

142. The rotational atherectomy device of claim 141 further comprising a flexible fluid supply tubing attached to the exchangeable drive shaft cartridge and in fluid communication with a drive shaft lumen of the drive shaft cartridge, the drive shaft lumen including a reduced inner diameter segment, the reduced inner diameter segment being positioned proximally of where the fluid supply tubing delivers fluid to the drive shaft lumen, thereby reducing flow of fluid proximally along the drive shaft lumen.

143. A rotational atherectomy device comprising:

a) an exchangeable drive shaft cartridge comprising a rotatable drive shaft socket carried by a drive shaft carriage; and

a rotatable flexible drive shaft having a proximal, intermediate and distal portions, the proximal portion being attached to the drive shaft socket, the intermediate portion being disposed primarily within a catheter, and the distal portion extending distally from the catheter and having a tissue removal implement;

b) a flexible fluid supply tubing connected to the drive shaft cartridge distally of the drive shaft socket;

c) a rotatable, radially expandable prime mover coupling carried by a prime mover carriage and connected to a prime mover for rotation therewith;

the drive shaft socket being sized to receive a length of the prime mover coupling therein such that the prime mover coupling does not effectively engage an interior of the drive shaft socket when the coupling is not rotating, but the prime mover coupling radially expands to effectively engage the socket upon sufficiently rapid rotation of the prime mover, causing the socket and the drive shaft to rotate together with the prime mover coupling and the prime mover,

whereby when the prime mover is not rotating, the drive shaft is disconnected from the prime mover, thereby permitting the exchangeable drive shaft cartridge to be replaced by another exchangeable drive shaft cartridge.

144. The rotational atherectomy device of claim 143 wherein one of the prime mover carriage and the drive shaft carriage is stationary and the other of the prime mover carriage and the drive shaft carriage can be moved longitudinally with respect to the stationary carriage.

145. A rotational atherectomy device comprising:

a. an exchangeable drive shaft cartridge comprising a housing;

a drive shaft carriage positioned proximally of the housing;

a rotatable drive shaft socket carried by the drive shaft carriage;

a flexible fluid supply tubing connected to the housing distally of the drive shaft socket;

a catheter extending distally from the housing; and

a rotatable flexible drive shaft having proximal, intermediate and distal portions, the proximal portion being attached to the drive shaft socket, the intermediate portion being disposed primarily within the catheter, and the distal portion extending distally from the catheter and having a tissue removal implement;

b. a rotatable, radially expandable prime mover coupling connected to a prime mover for rotation therewith, the prime mover being carried by a prime mover carriage and the prime mover coupling including a radially expandable portion;

the drive shaft socket being sized to receive a length of the radially expandable portion of the prime mover coupling therein such that the radially expandable portion of the prime mover coupling does not effectively engage an interior of the drive shaft socket when the coupling is not rotating, but the radially expandable portion of the prime mover coupling radially expands to effectively engage the socket upon sufficiently rapid rotation of the prime mover, causing the socket and the drive shaft to rotate together with the prime mover coupling and the prime mover,

whereby when the prime mover is not rotating, the drive shaft is disconnected from the prime mover, thereby permitting the exchangeable drive shaft cartridge to be replaced by another exchangeable drive shaft cartridge.

151. A system for releasably connecting a drive shaft to a prime mover comprising:

a) an exchangeable drive shaft cartridge comprising a rotatable drive shaft socket carried by a drive shaft carriage and a rotatable drive shaft having a proximal portion attached to the drive shaft socket;

b) a rotatable, radially expandable prime mover coupling connected to a prime mover for rotation therewith, the prime mover coupling comprising a coupling base and at least two flexible pins, each pin being anchored adjacent one end thereof to the coupling base and having another end which is free to deflect radially outwardly to engage the drive shaft socket when the prime mover is rotated;

the drive shaft socket being sized to receive free end portions of the pins of the prime mover coupling therein such that the pins do not contact the interior surface of the drive shaft socket when the coupling is not rotating, but the free end portions of the pins deflect into frictional engagement with the socket upon sufficiently rapid rotation of the prime mover, causing the socket and the drive shaft to rotate together with the prime mover coupling and the prime mover,

whereby when the prime mover is not rotating, the drive shaft is disconnected from the prime mover, thereby permitting the exchangeable drive shaft cartridge to be replaced by another exchangeable drive shaft cartridge.

152. The system of claim 151 wherein the coupling base includes at least one abutment spaced radially outwardly from each pin when the coupling base is not rotated and limiting outward deflection of an intermediate point along the length of the pin when the prime mover is rotated.

153. A method of removing tissue, comprising:

a) providing a tissue removal device which comprises;

i) an exchangeable drive shaft cartridge comprising a rotatable drive shaft socket carried by a drive shaft carriage;

a longitudinally extendable tube extending distally from the drive shaft carriage;

an elongated catheter having a proximal end portion which is operatively connected to a distal end portion of the longitudinally extendable tube; and

a rotatable flexible drive shaft having proximal, intermediate and distal portions, the proximal portion being attached to the drive shaft socket, the intermediate portion being disposed primarily within the tube and the catheter, and the distal portion extending distally from the catheter and having a tissue removal implement; and

ii) a rotatable, radially expandable prime mover coupling carried by a prime mover carriage and connected to a prime mover for rotation therewith;

b) positioning a length of the prime mover coupling within the drive shaft socket such that the prime mover coupling does not effectively engage an interior surface of the drive shaft socket;

c) rotating the prime mover and the prime mover coupling at a speed sufficient to cause the prime mover coupling to radially expand to effectively engage the socket, causing the socket, the drive shaft and the tissue removal implement to rotate together with the prime mover coupling and the prime mover;

d) contacting tissue with the tissue removal implement;

e) removing tissue with the tissue removal implement; and

f) stopping rotation of the prime mover, thereby disconnecting the drive shaft from the prime mover.

154. The method of claim 153 further comprising, after stopping rotation of the prime mover, replacing the exchangeable drive shaft cartridge with another exchangeable drive shaft cartridge.

155. A method of removing tissue, comprising:

a) providing a tissue removal device which comprises;

i) an exchangeable drive shaft cartridge comprising a rotatable drive shaft socket carried by a drive shaft carriage;

a longitudinally extendable tube extending distally from the drive shaft carriage;

an elongated catheter having a proximal end portion which is operatively connected to a distal end portion of the longitudinally extendable tube; and

a rotatable flexible drive shaft having proximal, intermediate and distal portions, the proximal portion being attached to the drive shaft socket, the intermediate portion being disposed primarily within the tube and the catheter, and the distal portion extending distally from the catheter and having a tissue removal implement; and

ii) a rotatable, radially expandable prime mover coupling carried by a prime mover carriage and connected to a prime mover for rotation therewith;

b) positioning a length of the prime mover coupling within the drive shaft socket such that the prime mover coupling does not effectively engage an interior surface of the drive shaft socket;

c) advancing the flexible drive shaft and the catheter over a guide wire into a body passageway of interest;

d) thereafter, rotating the prime mover coupling at a speed sufficient to cause it to radially expand to effectively engage the socket, causing the socket and the drive shaft to rotate together with the prime mover coupling and the prime mover;

e) advancing the rotating flexible drive shaft and its tissue removal implement against tissue;

f) removing tissue with the tissue removal implement; and

g) stopping rotation of the prime mover, thereby disconnecting the drive shaft from the prime mover.

156. The method of claim 155 further comprising, after stopping rotation of the prime mover, replacing the exchangeable drive shaft cartridge with another exchangeable drive shaft cartridge.

157. The method of 156 further comprising, after replacing the exchangeable drive shaft cartridge, repeating steps b-f.