Hegde, Anant V. (Newark, CA, US)
Buch, Wally S. (Atherton, CA, US)

Plaque It!

10/681821

07/29/2004

10/07/2003

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600/16

(IPC1-7): A61M001/10

COOLEY GODWARD, LLP (3000 EL CAMINO REAL, PALO ALTO, CA, 94306, US)

1. A device, comprising: a compliant first layer configured to engage internal vasculature; a second layer coupled to the first layer, the second layer having a stiffness greater than a stiffness of the first layer; and the first layer and the second layer defining a cavity therebetween, the cavity having a volume wherein the first layer is configured to be deformed in response to a change in the volume of the cavity.

2. The device of claim 1 wherein the first layer is selectively radially deformed in response to a change in the volume of the cavity.

3. The device of claim 1, wherein the first layer is fabricated with a first material and the second layer is fabricated with a second material.

4. The device of claim 3, wherein the first material is a first silicone elastomer and the second material is a second silicone elastomer.

5. The device according to claim 1 wherein a portion of the device is coated with a tissue growth inducing polymeric material.

6. The device according to claim 5 wherein the tissue growth inducing material is one of poly-L-lysine and poly-D-lysine.

7. The device of claim 4, wherein the first silicone elastomer is a 5-50 A silicone elastomer having a minimum of 500% elongation.

8. The device of claim 4, wherein the second silicone elastomer is a 65-95 A silicone elastomer having less than a 400% elongation.

9. The device of claim 1 wherein the second layer further comprises a reinforcement element coupled to the second layer such that the reinforcement element is configured to maintain the length and width of the second layer.

10. The device of claim 4, wherein the first material is an elastomer that has hardness of 5-50 shore A and having a minimum elongation of 500%.

11. The device of claim 4, wherein the second material is an elastomer that has hardness of 65-95 shore A and having a maximum elongation of 400%.

12. The device of claim 9, wherein the reinforcement element is fabricated from at least one of polyester, nylon, para-aramid fiber, stainless steel, platinum, superelastic nitinol and alloys of nickel and titanium.

13. The device of claim 3, wherein the first and second material are one of silicone, neoprene and copolymers comprising styrene and butadiene.

14. The device of claim 1, wherein the first layer is coupled to the second layer about a perimeter of the first layer.

15. The device of claim 1, wherein the first layer is coupled to the second layer about a portion of the perimeter of the second layer.

16. The device of claim 14, wherein a perimeter of the second layer extends beyond the perimeter of the first layer.

17. The device of claim 1, the second layer further comprising a length and a width, the first layer further comprising a length and a width, wherein the length of the first layer is less than the length of the second layer.

18. The device of claim 17, wherein the width of the first layer is less than the width of the second layer.

19. The device of claim 17 wherein the length of the second layer is sufficient for the second layer to completely encircle a portion of a blood vessel.

20. The device of claim 19 having a second layer further comprising a fist end and a second end wherein when the second layer is configured to completely encircle a portion of a blood vessel, the first end and the second end of the second layer overlap.

21. The device of claim 19 wherein the portion of the blood vessel comprises the ascending aorta.

22. The device of claim 19 wherein the portion of the blood vessel comprises the descending aorta.

23. The device of claim 19 wherein the portion of the blood vessel comprises a set of intercostal arteries or a set of intercostal veins.

24. The device of claim 19, wherein the portion of the blood vessel comprises the superior vena cava.

25. The device of claim 19, wherein the portion of the blood vessel comprises the inferior vena cava.

26. The device of claim 1 wherein the second layer further comprising a first end and a second end, wherein each of the first end and the second end have at least two tabs, each of the tabs in the at least two tabs has a width wherein the sum of the widths of all the tabs in the at least two tabs on the first end is less than the width of the device.

27. The device of claim 26, wherein the at least two tabs on the first and second ends are configured to be removably coupled such that the device is reconfigurable between a first configuration in which the at least two tabs on the first and second ends are separate and a second configuration in which the at least two tabs on the first and second ends are coupled.

28. The device of claim 26 wherein a tab spacing profile is provided between adjacent tabs in the at least two tabs, the tab spacing profile having a width wherein the sum of the tab spacing profile widths and the widths of all of the tabs in the at least two tabs equals the width of the device.

29. The device of claim 28 wherein the tab spacing profile between each of the tabs in the at least two tabs is the same.

30. The device of claim 28 having at least two different tab spacing profiles.

31. The device of claim 26 wherein when the device is disposed about a blood vessel in a body at least one of the two or more tabs of the first end is coupled to at least one of the two or more tabs on the second end.

32. The device of claim 28, wherein the tab widths and tab spacing profiles are selected such that when the at least one tab on the first end is coupled to at least one tab on the second end the device encircles a portion of a blood vessel and a side branch coupled to the blood vessel without restricting blood flow into or from the side branch.

33. The device of claim 32, wherein the portion of a blood vessel and a side branch comprises the descending aorta and at least one set of intercostal arteries.

34. The device of claim 32, wherein the portion of a blood vessel and a side branch comprises the inferior vena cava and at least one set of intercostal veins.

35. The device of claim 20, wherein the second layer first and second ends are configured to be removably coupled such that the device is reconfigurable between a first configuration in which the first and second ends are separate and a second configuration in which the first and second ends are coupled.

36. The device of claim 1 wherein the perimeter of the first layer perimeter defines a first shape and the perimeter of the second layer defines a second shape.

37. The device of claim 36 wherein the first shape is similar to the second shape.

38. The device of claim 36 wherein the second shape is rectangular and first shape is a different shape than the second shape.

39. The device of claim 1 further comprising an expandable bladder having a volume and disposed within the cavity and configured such that the first layer is deformed in response to a change in volume of the bladder.

40. device, comprising: an expandable layer configured to engage internal vasculature; a cover layer coupled to the expandable layer and having a length and a width, the expandable layer and the cover layer defining a cavity therebetween, the cavity having a volume, the cover layer defining an opening in fluid communication with the cavity; and a reinforcement element coupled to the cover layer and configured to maintain the length and width of the cover layer, wherein, the expandable layer is configured to be selectively deformed in response to a change in the volume of the cavity.

41. The device of claim 40, wherein selectively deformed is a deformation that is radially selective.

42. The device of claim 40, selectively deformed is a deformation that is longitudinally selective.

43. The device of claim 40, wherein the first layer is fabricated with a first material having a first stiffness and the second layer is fabricated with a second material having a second stiffness.

44. The device of claim 43 wherein the second stiffness is greater than the first stiffness.

45. The device of claim 44, wherein the first material is a first silicone elastomer and the second material is a second silicone elastomer.

46. The device of claim 45, wherein the first silicone elastomer is a 5-50 A silicone elastomer having a minimum of 500% elongation.

47. The device of claim 45, wherein the second silicone elastomer is a 65-95 A silicone elastomer having less than a 400% elongation.

48. The device of claim 40, wherein the reinforcement element is at least one of polyester, nylon, para-aramid fiber, stainless steel, platinum, superelastic nitinol and alloys of nickel and titanium.

49. The device of claim 45, wherein the first material is an elastomer that has hardness of 5-50 shore A and having a minimum elongation of 500%.

50. The device of claim 45, wherein the second material is an elastomer that has hardness of 65-95 shore A and having a maximum elongation of 400%.

51. The device of claim 43, wherein the first material and second material are one of silicone, neoprene and copolymers comprising styrene and butadiene.

52. The device of claim 40, wherein the device is reconfigurable between a first, substantially planar configuration and a second, substantially tubular configuration.

53. The device of claim 52, further comprising a connection member joining a first portion of the cover layer to a second portion of the cover layer when the device is in the second configuration.

54. The device of claim 40, wherein the cover layer includes a first end and a second end, said first end and said second end configured to be removably coupled such that the device is reconfigurable between a first configuration in which the first and second ends are separate and a second configuration in which the first and second ends are coupled.

55. The device of claim 54 wherein when the first end and the second end are coupled the first end and the second end are in an overlapping configuration that encircles a portion of a blood vessel.

56. The device of claim 55 wherein the portion of the blood vessel comprises the ascending aorta.

57. The device of claim 55 wherein the portion of the blood vessel comprises the descending aorta.

58. The device of claim 55 wherein the portion of the blood vessel comprises a set of intercostal arteries or a set of intercostal veins.

59. The device of claim 55, wherein the portion of the blood vessel comprises the superior vena cava.

60. The device of claim 55, wherein the portion of the blood vessel comprises the inferior vena cava.

61. The device of claim 40 wherein the cover layer further comprises a first end and a second end, wherein each of the first end and the second end have at least two tabs, each of the tabs in the at least two tabs has a width wherein the sum of the widths of all the tabs in the at least two tabs on the first end is less than the width of the device.

62. The device of claim 61, wherein the at least two tabs on the first and second ends are configured to be removably coupled such that the device is reconfigurable between a first configuration in which the at least two tabs on the first and second ends are separate and a second configuration in which the at least two tabs on the first and second ends are coupled.

63. The device of claim 61 wherein a tab spacing profile is provided between adjacent tabs in the at least two tabs, the tab spacing profile having a width wherein the sum of the tab spacing profile widths and the widths of all of the tabs in the at least two tabs equals the width of the device.

64. The device of claim 63 wherein the tab spacing profile between each of the tabs in the at least two tabs is the same.

65. The device of claim 63 having at least two different tab spacing profiles.

66. The device of claim 61 wherein when the device is disposed about a blood vessel in a body at least one of the two or more tabs of the first end is coupled to at least one of the two or more tabs on the second end.

67. The device of claim 63, wherein the tab widths and tab spacing profiles are selected such that when the at least one tab on the first end is coupled to at least one tab on the second end the device encircles a portion of a blood vessel and a side branch coupled to the blood vessel without restricting blood flow into or from the side branch.

68. The device of claim 67, wherein the portion of a blood vessel and a side branch comprises the descending aorta and at least one set of intercostal arteries.

69. The device of claim 67, wherein the portion of a blood vessel and a side branch comprises the inferior vena cava and at least one set of intercostal veins.

70. The device of claim 54, wherein the first end and the second end include cooperating portions of a mating fastener.

71. The device of claim 54, wherein the first end and the second end are configured to be sewn together.

72. The device of claim 70, wherein the mating fasteners are magnets.

73. The device of claim 70, wherein at least one of the mating fasteners is magnetic.

74. The device of claim 70, wherein a one the mating fasteners is a magnet and the other mating fastener is formed from a magnetically attractive material.

75. The device of claim 70, wherein the mating fasteners are opposite sides of a buckle.

76. The device of claim 70, wherein the mating fasteners are a screw and a screw-receiving opening.

77. The device of claim 70 wherein the mating fasteners are a hook and a loop.

78. The device of claim 70 wherein the mating fasteners comprise a plurality of hooks and a plurality of loops.

79. The device of claim 70 wherein the mating fasteners include a locking ring and a mating element.

80. The device of claim 70 wherein the mating fasteners include a positive-locks.

81. The device of claim 40, further comprising: a conduit coupled to the second layer in communication with the opening, the conduit configured to be coupled to a pump.

82. The device of claim 81 wherein one of a fluid is configured to be selectively communicated in synchronization with the cardiac cycle to the cavity via a conduit in communication with the opening in the cover layer.

83. A vascular assist device configured to be coupled to at least a portion of a blood vessel, the device comprising: a vascular engaging layer; an expandable layer; a cover layer; and the device having an uninstalled configuration and an installed configuration; wherein, the vascular engaging layer is disposed between the outer wall of the blood vessel and the expanding layer; the cover layer and the expanding layer are coupled so as to form a cavity therebetween, the cavity being bounded by the expanding layer and the cover layer; the cover layer having an opening formed therein, the opening being in communication with the cavity and the cavity being configured to selectively receive a fluid via the opening whereby the fluid causes the volume of the cavity to change wherein the change in cavity volume causes the expanding layer to deform more than the cover layer to accommodate the change in cavity volume.

84. A vascular assist device according to claim 83 wherein the vascular engaging layer is sufficiently long to encircle a portion of the blood vessel.

85. A vascular assist device according to claim 83 wherein the expandable layer is sufficiently long to at least partially encircle a portion of the blood vessel.

86. A vascular assist device according to claim 83 wherein the vascular engaging layer is coupled to the expandable layer.

87. The device of claim 83, wherein the vascular engaging layer is fabricated with a first material, the expanding layer is fabricated with second material and the cover layer is fabricated with a third material different from the first and second material.

88. The device of claim 83, wherein the vascular engaging layer is a vascular graft.

89. The device of claim 88, wherein the vascular graft is made from a polymer selected from the group consisting of: polyester, nylon, polytetrafluoroethylene and polyvinylidene fluoride.

90. The device of claim 83, wherein the second material is a first silicone elastomer and the third material is a second silicone elastomer.

91. The device of claim 83, wherein the cover layer further comprises a reinforcement element selected from the group consisting of: polyester, nylon, para-aramid fiber, stainless steel, platinum, superelastic nitinol and alloys of nickel and titanium.

92. The device of claim 83 wherein the expanding layer and the cover layer are fabricated from a material selected from the group consisting of: silicone, neoprene, copolymers comprising styrene and copolymers comprising butadiene.

93. The device of claim 83, wherein the perimeter of the expanding layer is coupled to the cover layer.

94. The device of claim 93, wherein the perimeter of the expanding layer aligns with a portion of the perimeter of the cover layer.

95. The device of claim 83, wherein the device is repeatably configurable between the uninstalled configuration and the installed configuration.

96. The device of claim 95 wherein the cover layer further comprises at least one pair of cooperative fastening elements.

97. The device of claim 96 wherein when the device is in the uninstalled configuration the at least one pair of cooperative fastening elements are uncoupled.

98. The device of claim 96 wherein when the device is in the installed configuration the at least one pair of cooperative fastening elements are coupled.

99. The device of claim 96 wherein one of the fastening elements in the at least one pair of cooperative fastening elements comprises a plurality of fastening positions such that the size of the device in the installed configuration may be adjusted by changing to which of said plurality of fastening positions the other fastening element is coupled.

100. The device of claim 83 wherein the cover layer includes a first end and a second end, said first end and said second end configured to be removeably coupled such that the device is reconfigurable between an uninstalled configuration in which the first and second ends are separate and an installed configuration in which the first and second ends are coupled.

101. The device of claim 83 wherein the device is maintained in an installed configuration about a portion of a blood vessel by suturing a first portion of the vascular engaging layer to a second portion of the vascular engaging layer.

102. The device according to claim 83 wherein a portion of the device is coated with a tissue growth inducing polymeric material.

103. The device according to claim 102 wherein the tissue growth inducing polymeric material is one of poly-L-lysine and poly-D-lysine.

104. A vascular assist device configured to be coupled to at least a portion of a blood vessel, the device comprising: a vascular engaging layer having a first stiffness; a cover layer having a second stiffness that is greater than the first stiffness and being coupled to the vascular engaging layer such that a portion of the cover layer extends past at least a portion of the perimeter of the vascular engaging layer; the cover layer and the vascular engaging layer forming a cavity therebetween, the cover layer having an opening formed therein in communication with the cavity, the cavity being configured to selectively receive a fluid via the opening; and the device having an uninstalled configuration and an installed configuration.

105. A vascular assist device according to claim 104 wherein the vascular engaging layer is sufficiently long to at least partially encircle a portion of the aorta.

106. A vascular assist device according to claim 104 wherein the vascular engaging layer is sufficiently long to at least partially encircle a portion of the vena cava.

107. The device of claim 104, wherein the vascular engaging layer is fabricated with a first material and the cover layer is fabricated with a second material different from the first material.

108. The device of claim 107, wherein the first material is a first silicone elastomer and the second material is a second silicone elastomer.

109. The device of claim 104, wherein the cover layer further comprises a reinforcement element selected from the group consisting of: polyester, nylon, para-aramid fiber, stainless steel, platinum, superelastic nitinol and alloys of nickel and titanium.

110. The device of claim 107, wherein the first and second material are one of silicone, neoprene, copolymers comprising styrene and copolymers comprising butadiene silicone, neoprene and copolymers comprising styrene and butadiene.

111. The device of claim 104, wherein the perimeter of the vascular engaging layer is coupled to the cover layer.

112. The device of claim 111, wherein the perimeter of the vascular engaging layer aligns with a portion of the perimeter of the cover layer.

113. The device of claim 111, wherein the perimeter of the cover layer extends beyond the perimeter of the vascular layer.

114. The device of claim 104, wherein the device is repeatably configurable between the uninstalled configuration and the installed configuration.

115. The device of claim 114 wherein the cover layer further comprises at least one pair of cooperative fastening elements.

116. The device of claim 115 wherein when the device is in the uninstalled configuration the at least one pair of cooperative fastening elements are uncoupled.

117. The device of claim 115 wherein when the device is in the installed configuration the at least one pair of cooperative fastening elements are coupled.

118. The device of claim 115 wherein one of the fastening elements in the at least one pair of cooperative fastening elements comprises a plurality of fastening positions such that the size of the device in the installed configuration may be adjusted by changing to which of said plurality of fastening positions the other fastening element is coupled.

119. The device of claim 104 wherein the cover layer includes a first end and a second end, said first end and said second end configured to be removeably coupled such that the device is reconfigurable between an uninstalled configuration in which the first and second ends are separate and an installed configuration in which the first and second ends are coupled.

120. The device according to claim 104 wherein a portion of the device is coated with a tissue growth inducing polymeric material.

121. The device according to claim 120 wherein the tissue growth inducing polymeric material is one of poly-L-lysine and poly-D-lysine.

122. A system, comprising: a pump having a controller configured to receive a signal associated with the cardiac cycle of a heart; a cuff comprising, a compliant first layer configured to engage internal vasculature; a second layer coupled to the first layer and having a stiffness greater than a stiffness of the first layer and having an opening formed therein; the compliant first layer and the second layer being coupled to form a cavity bounded by the first layer and the second layer, the cavity being in communication with the opening in the second layer; and a conduit coupled between the opening and the pump, the conduit configured to convey a fluid between the pump and the cavity thereby causing deformation of the first layer by expanding and contracting the cavity.

123. The system of claim 122 wherein the signal associated with the cardiac cycle is related to systole.

124. The system of claim 122 wherein the signal associated with the cardiac cycle is related to diastole.

125. The system of claim 122 wherein the signal associated with the cardiac cycle is related to a change in aortic pressure.

126. The system of claim 122 wherein the signal associated with the cardiac cycle is related to a change in arterial pressure.

127. The system of claim 122 wherein the signal associated with the cardiac cycle is related to a change in venous pressure.

128. The system of claim 122 wherein the pump is a pulsitile pump.

129. The system of claim 122 wherein the pump, cuff and conduit are implantable within a human body.

130. The system of claim 122 further comprising a sensor configured to generate a signal associated with the cardiac cycle of a heart.

131. The system of claim 130 herein the sensor is a pressure sensor.

132. The system of claim 131 wherein the sensor is part of the cuff.

133. The system of claim 130 wherein the sensor is an electrical sensor.

134. The system of claim 133 wherein the sensor is part of the cuff.

135. The system of claim 122 wherein the second layer includes a first end and a second end, said first end and said second end configured to be removeably coupled such that the cuff is reconfigurable between an uninstalled configuration in which the first and second ends are separate and an installed configuration in which the first and second ends are coupled.

136. The system of claim 135 wherein the installed configuration comprises a plurality of coupling positions whereby the size of the cuff may be adjusted by changing into which one of the plurality of coupling positions the first and second ends are coupled.

137. The system of claim 122, wherein the first layer is fabricated with a first material and the second layer is fabricated with a second material different from the first material.

138. The device of claim 122 wherein the second layer further comprising a first end and a second end, wherein each of the first end and the second end have at least two tabs, each of the tabs in the at least two tabs has a width wherein the sum of the widths of all the tabs in the at least two tabs on the first end is less than the width of the cuff.

139. The device of claim 138, wherein the at least two tabs on the first and second ends are configured to be removably coupled such that the device is reconfigurable between a first configuration in which the at least two tabs on the first and second ends are separate and a second configuration in which the at least two tabs on the first and second ends are coupled.

140. The device of claim 138 wherein a tab spacing profile is provided between adjacent tabs in the at least two tabs, the tab spacing profile having a width wherein the sum of the tab spacing profile widths and the widths of all of the tabs in the at least two tabs equals the width of the device.

141. The device of claim 140 wherein the tab spacing profile between each of the tabs in the at least two tabs is the same.

142. The device of claim 140 having at least two different tab spacing profiles.

143. The device of claim 138 wherein when the device is disposed about a blood vessel in a body at least one of the two or more tabs of the first end is coupled to at least one of the two or more tabs on the second end.

144. The device of claim 140, wherein the tab widths and tab spacing profiles are selected such that when the at least one tab on the first end is coupled to at least one tab on the second end the device encircles a portion of a blood vessel and a side branch coupled to the blood vessel without restricting blood flow into or from the side branch.

145. The device of claim 144, wherein the portion of a blood vessel and a side branch comprises the descending aorta and at least one set of intercostal arteries.

146. The device of claim 144, wherein the portion of a blood vessel and a side branch comprises the inferior vena cava and at least one set of intercostal veins.

147. The system of claim 122, wherein the conduit further comprises a first end configured to have a single lumen and a second end configured to have a plurality of lumens.

148. The system of claim 147, wherein each lumen has the same diameter.

149. The system of claim 147, wherein at least one lumen has a diameter different from the diameter of another lumen.

150. The system of claim 122, wherein the cavity is coupled to a plurality of conduits.

151. The system of claim 150, wherein one of the plurality of conduits supplies fluid from the pump to the cavity.

152. The system of claim 151, wherein another one of the plurality of conduits returns fluid from the cavity to the pump.

153. The system of claim 122, wherein the conduit has a first diameter adjacent to the opening and a second different diameter at a point distal to the opening.

154. The system of claim 122, wherein the conduit comprises a plurality of conduits wherein at least one of the conduits in the plurality of conduits has a diameter that is different from the diameter of at least one other of the plurlity of conduits.

155. The system of claim 137, wherein the first material is a first silicone elastomer and the second material is a second silicone elastomer.

156. The system of claim 122 wherein the fluid is a liquid is selected from the group consisting of: saline, water, glycols, a combination comprising a glycol and saline and a combination comprising a glycol and water.

157. The system of claim 122 wherein the fluid is a gas that is chemically inert with the first and second layers.

158. The system of claim 157 wherein the fluid is a gas that is one of either carbon dioxide or nitrogen.

159. The system of claim 122 wherein the fluid is a gas having lower density than air.

160. The system of claim 159 wherein the gas is helium.

161. The system of claim 122 further comprising a fluid volume compensator.

162. The system of claim 161 wherein the fluid conpensator is disposed in a fluid flow path between the pump and the cavity.

163. The system of claim 161 wherein the fluid compensator is configured to adjust the fluid volume ported into the cavity during activation of the cuff.

164. The system of claim 161 wherein the fluid compensator is configured to allow replenishment of the fluid in the system.

165. The system of claim 122 wherein a surface of one of the cuff, conduit and pump in contact with the fluid are coated with a material to enhance lubricity.

166. The system of claim 122 wherein a surface of one of the cuff, conduit and pump in contact with the fluid is coated with a material to reduce fluid evaporation.

167. The system of claim 122 wherein an interior surface of one of the cuff, conduit and pump is coated with a material to reduce fluid loss.

168. The system of claim 122 wherein a surface of one of the cuff, conduit and pump is coated with a material to reduce fluid loss.

169. The system of claim 122 wherein the condiut further comprises a reinforcement element.

170. The system of claim 169 wherein the reinforcement element is selected from the group consisting of: polyester, nylon, para-aramid fiber, stainless steel, platinum, superelastic nitinol and alloys of nickel and titanium.

171. A method for augmenting blood flow in a patient body using a cuff formed from a first layer joined to a second layer so that a cavity exists between the layers such that filling the cavity preferentially deforms the first layer, the method comprising: detecting a first cardiac cycle trigger; porting a fluid into the cavity so as to elastically deform the first layer thereby compressing a blood vessel in response to the first cardiac cycle trigger; and porting a fluid out of the cavity in response to a second cardiac cycle trigger.

172. A method for augmenting blood flow in a body according to claim 171 wherein the first cardiac trigger is related to an ECG of the patient.

173. A method for augmenting blood flow in a body according to claim 171 wherein the first cardiac trigger is related to the increasing portion of the R-wave.

174. A method for augmenting blood flow in a body according to claim 173 wherein the first cardiac trigger occurs at 90% of the increasing R-wave amplitude.

175. A method for augmenting blood flow in a body according to claim 171 wherein the first cardiac trigger is related to the ECG of the patient and selected so that the step of porting a fluid into the cavity so as to elastically deform the first layer coincides with the ventricular systole.

176. A method for augmenting blood flow in a body according to claim 171 wherein the second cardiac cycle trigger is a predetermined time limit.

177. A method for augmenting blood flow in a body according to claim 171 wherein the second cardiac cycle trigger is based on the R-R interval.

178. A method for augmenting blood flow in a body according to claim 171 wherein the second cardiac cycle trigger is related to aortic pressure.

179. A method for augmenting blood flow in a body according to claim 171 wherein the first and the second cardiac cycle triggers are selected to operate the cuff in copulsation mode.

180. A method for augmenting blood flow in a body according to claim 171 wherein the cavity inflates during the ventricular systole of the heart.

181. A method for augmenting blood flow in a body according to claim 171 wherein the first cardiac trigger is related to the Q-T interval.

182. A method for augmenting blood flow in a body according to claim 171 wherein the first cardiac trigger is related to the decreasing portion of the T-wave.

183. A method for augmenting blood flow in a body according to claim 182 wherein the first cardiac trigger occurs at the end of the T-wave.

184. A method for augmenting blood flow in a body according to claim 171 wherein the first cardiac trigger is related to the T-wave and selected so that the step of porting a fluid into the cavity so as to elastically deform the first layer coincides with the ventricular diastole.

185. A method for augmenting blood flow in a body according to claim 181 wherein the second cardiac cycle trigger is a predetermined time limit.

186. A method for augmenting blood flow in a body according to claim 181 wherein the second cardiac cycle trigger is based on the R-R interval.

187. A method for augmenting blood flow in a body according to claim 181 wherein the second cardiac cycle trigger is related to aortic pressure.

188. A method for augmenting blood flow in a body according to claim 171 wherein the first and the second cardiac cycle triggers are selected to operate the cuff in counterpulsation mode.

189. A method for augmenting blood flow in a body according to claim 171 wherein the cavity inflates during the ventricular diastole of the heart.

190. A method for augmenting blood flow in a body using a cuff formed from a first layer joined to a second layer so that a cavity exists between the layers such that filling the cavity preferentially deforms the first layer, the method comprising: detecting a cardiac cycle trigger; porting a fluid into the cavity so as to elastically deform the first layer thereby compressing a blood vessel in response to the cardiac cycle trigger; holding the vessel compressed for known duration and porting a fluid out of the cavity at the end of the duration in order to allow the vessel to relax.

191. A method for augmenting blood flow in a body according to claim 190 wherein the cardiac trigger is related to the ECG.

192. A method for augmenting blood flow in a body according to claim 190 wherein the cardiac trigger is related to the increasing portion of the R-wave of the ECG.

193. A method for augmenting blood flow in a body according to claim 192 in a coplusation manner wherein the first cardiac trigger occurs at 90% of the increasing R-wave amplitude.

194. A method for augmenting blood flow in a body according to claim 190 in a coplusation manner wherein the cardiac trigger is related to the aortic pressure and selected so that the step of porting a fluid into the cavity so as to elastically deform the first layer coincides with the ventricular systole.

195. A method for augmenting blood flow in a body according to claim 190 in counterpulsation manner, wherein the cardiac trigger is related to detecting R-wave of the ECG, computing the Q-T interval and triggering the pump to coincide with the end of the T-wave for porting the fluid into the cavity so as to elastically deform the first layer and compress the blood vessel.

196. A method for augmenting blood flow in a body according to claim 190 in counterpulsation manner, wherein the cardiac trigger is related to detecting the peak aortic pressure and computing the duration for the aortic valve to close and triggering the pump for porting the fluid into the cavity so as to elastically deform the first layer and compress the blood vessel to coincide with the aortic valve closing.

197. A method for augmenting blood flow in a vessel of a patient using a cuff having a compliant first layer that at least partially encircles a vessel adjacent the cuff, a second layer coupled to the first layer, the first layer and the second layer defining a cavity therebetween, the method comprising: changing the pressure of a fluid in the cavity based on a signal associated with the cardiac cycle; deforming the first layer in response to the changing pressure of the fluid in the cavity; and deforming the walls of a vessel at least partially encircled by the first layer in response to the deforming of the first layer.

198. A method for augmenting blood flow in a vessel according to claim 197 wherein the signal associated with the cardiac cycle is related to the ECG of the patient.

199. A method for augmenting blood flow in a vessel according to claim 197 wherein the signal associated with the cardiac cycle is related to the increasing portion of the R-wave.

200. A method for augmenting blood flow in a vessel according to claim 197 wherein the signal associated with the cardiac cycle is related to the ECG of the patient and selected so that the step of deforming the walls of a vessel at least partially encircled by the first layer in response to the deforming of the first layer coincides with the ventricular systole.

201. A method for augmenting blood flow in a vessel according to claim 197 wherein the signal associated with the cardiac cycle is related to aortic pressure.

202. A method for augmenting blood flow in a vessel according to claim 197 wherein the changing the pressure of a fluid in the cavity is selected such that the blood flow in the vessel is augmented in a copulsation mode.

203. A method for augmenting blood flow in a vessel according to claim 197 wherein the changing the pressure of a fluid in the cavity is occurring so that the pressure in the cavity is increasing during the ventricular systole of the heart.

204. A method for augmenting blood flow in a vessel according to claim 197 wherein the signal associated with the cardiac cycle is related to the Q-T interval.

205. A method for augmenting blood flow in a vessel according to claim 197 wherein the signal associated with the cardiac cycle is related to the decreasing portion of the T-wave.

206. A method for augmenting blood flow in a vessel according to claim 197 wherein the signal associated with the cardiac cycle occurs at the end of the T-wave.

207. A method for augmenting blood flow in a vessel according to claim 197 wherein the signal associated with the cardiac cycle is related to the T-wave and selected so that the step of changing the pressure of a fluid in the cavity coincides with the ventricular diastole.

208. A method for augmenting blood flow in a vessel according to claim 197 wherein the changing the pressure of a fluid in the cavity is selected such that the blood flow in the vessel is augmented in a counterpulsation mode.

209. A method for augmenting blood flow in a vessel according to claim 197 wherein the changing the pressure of a fluid in the cavity is occurring so that the pressure in the cavity is increasing during the ventricular diastole of the heart.

210. A method for augmenting blood flow in a vessel according to claim 197 wherein increasing the pressure in the cavity results in deforming the first layer so as to constrict the vessel.

211. A system, comprising: a plurality of cuffs, each of the plurality of cuffs including a compliant first layer configured to engage internal vasculature; a second layer coupled to the first layer, the first layer and the second layer defining a cavity therebetween, the second layer defining an opening in communication with the cavity; and a connector configured to couple the plurality of cuffs to one another.

212. The system of claim 211, wherein the connector is coupled to the second layer of each of the plurality of cuffs.

213. The system of claim 211, wherein the connector further comprises a conduit coupled between the connector and an opening.

214. The system of claim 211, wherein at least one of the plurality of cuffs is coupled to the vasculature of a body.

215. The system of claim 214, wherein at least one of the plurality of cuffs is coupled to an organ in a body.

216. The system of claim 211 wherein at least one of the plurality of cuffs is configured to engage with at least one set of intercostal arteries.

217. The system of claim 211 wherein at least one of the plurality of cuffs is configured to engage with at least one set of intercostal veins.

218. The system of claim 211 wherein at least one of the plurality of cuffs is configured to engage with the ascending aorta.

219. The system of claim 211 wherein at least one of the plurality of cuffs is configured to engage with the descending aorta.

220. The system of claim 211, wherein plurality of cuffs are configured to engage with the superior vena cava.

221. The system of claim 211, wherein plurality of cuffs are configured to engage with the inferior vena cava.

222. The system of claim 211, wherein each of the plurality of cuffs is repeatably configurable between an uninstalled configuration and an installed configuration.

223. The system of claim 222 wherein the second layer of each of the plurality of cuffs further comprises at least one pair of cooperative fastening elements.

224. The system of claim 223 wherein when a cuff is in the uninstalled configuration the at least one pair of cooperative fastening elements are uncoupled.

225. The system of claim 223 wherein when a cuff is in the installed configuration the at least one pair of cooperative fastening elements are coupled.

226. The system of claim 223 wherein one of the fastening elements in the at least one pair of cooperative fastening elements comprises a plurality of fastening positions such that the size of the cuff in the installed configuration may be adjusted by changing to which of said plurality of fastening positions the other fastening element is coupled.

227. The system of claim 211 wherein the second layer of each of the plurality of cuffs includes a first end and a second end, said first end and said second end configured to be removeably coupled such that the cuff is reconfigurable between an uninstalled configuration in which the first and second ends are separate and an installed configuration in which the first and second ends are coupled.

228. The system of claim 211 further comprising: a pump in communication with the connector; and a controller for providing control signals to the pump in response to triggering signals from a cardiac cycle.

229. The system of claim 228 configured so that each of the plurality of cuffs is operated sequentially.

230. The system of claim 228 configured so that each of the plurality of cuffs is operated simultaneously.

231. The system of claim 228 configured so that each of the plurality of cuffs is operated to augment blood flow in the internal vasculature in a counterpulsation mode.

232. The system of claim 228 configured so that each of the plurality of cuffs is operated to augment blood flow in the internal vasculature in a copulsation mode.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority under 35 U.S.C. 119 to provisional application serial No. 60/416,477, filed on Oct. 7, 2002, and entitled “Vascular Assist Device” the entirety of which is incorporated herein by reference.

BACKGROUND

[0002] 1. Field of the Invention

[0003] The present invention is directed to vascular assist devices and methods, and more particularly directed to vascular assist devices that are readily fabricated, installed, adjusted and removed.

[0004] 2. Description of the Related Art

[0005] Congestive heart failure is a condition that causes the heart to pump less efficiently. Typically the heart has been weakened over time by an underlying problem, such as clogged arteries, high blood pressure, a defect in its muscular walls or valves, or some other medical condition. The body depends on the heart's pumping action to deliver oxygen and nutrient-rich blood so it can function normally. In people with congestive heart failure, the body fails to get an adequate supply. As a result, they tend to feel weak, fatigued, or short of breath. Everyday activities such as walking, climbing stairs, carrying groceries and yard work can become quite difficult.

[0006] Congestive heart failure develops over time. The slow onset and progression of congestive heart failure is caused by the heart's own efforts to compensate for the weakening of the heart muscles. The heart tries to compensate for the weakening by enlarging and forcing a faster pumping rate to move more blood through the vasculature of the body.

[0007] If the left side of the heart is not working properly, blood and other fluids back up into the lungs leading to the shortness of breath and exhaustion discussed above. If the right side of the heart is not working properly, the slow blood flow causes build up of fluid in the veins causing the legs and ankles to show signs of swelling (edema). Edema often spreads to the lungs, liver, and stomach. Such a fluid buildup may also cause kidney failure due to the body's ability to dispose of salt and water. As heart failure progresses, a patient's heart becomes weaker and the symptoms begin to manifest.

[0008] People at risk for congestive heart failure may undertake various therapies to ease the workload of the heart. Such treatment may include lifestyle changes, medicines, transcatheter interventions, and surgery. While lifestyle changes and medicines are often effective non-invasive procedures that can be undertaken, they are not as effective as the alternative, albeit more invasive, procedures. That being said, transcatheter interventions and surgical procedures are highly invasive and can create substantial risk in more delicate patients (e.g., elderly people, obese people, etc.).

[0009] Examples of transcatheter interventions include angioplasty, stenting, and inotropic drug therapy. Surgical procedures include heart valve repair or replacement, pacemaker insertion, correction of congenital heart defects, coronary artery bypass surgery, mechanical assist devices, and heart transplant.

[0010] When the heart can no longer adequately function and a patient is at risk of dying it is referred to as end-stage congestive heart failure. In such cases heart transplants are often required. Mechanical assist devices such as ventricular assist devices (VADs) and axial pumps have proven to be effective in offloading the workload of the heart. These devices can act as a temporary assist for a patient's heart prior to transplant. Studies have shown that approximately twenty percent (20%) of people using VADs have recovered or healed by offloading the heart for some period of time.

[0011] Recently, ventricular assist devices have been considered as an alternative to heart transplant and have been successfully implanted in several patients worldwide. Ventricular assist devices are able to totally offload the heart, potentially leading to recovery of the heart.

[0012] There are several types of ventricular assist devices. Left ventricular assist devices that offload the left ventricle of the heart, right ventricular assist devices that offload the right ventricle of the heart and atrial assist devices that offload the atrium of the heart. These devices come into direct contact with the blood. Such direct blood contact is a major concern with respect to thrombus formation and it is necessary to give blood thinners and anticoagulants to patients fitted with such ventricular assist devices. To insert such a device it is necessary to make incisions in the heart chambers and aorta, thereby leading to infection at the implant site as well as around the conduits connecting to external devices.

[0013] Another type of assist device is the intra-aortic balloon pump (IABP). IABPs provide assistance by decreasing myocardial oxygen consumption by reducing heart afterload, as well as increasing coronary artery profusion by augmenting diastolic coronary artery flow. IABPs do not require surgical intervention to install, but rather is placed through an open approach to the common femoral artery.

[0014] Another device that is often used is an impeller, which is a miniature pump catheter that continuously pumps the blood. Aortomyplasty is another way to augment the diastolic pressure and increase coronary artery flow.

[0015] To avoid the problems of biomaterial interface and to avoid disadvantages of other known methods of increasing blood flow, devices that compress the aorta externally were developed. Such devices may often include rigid mechanical jaws that are not compliant, thereby increasing the likelihood of injury to the aorta. Additionally such devices limit the mobility of patients, thus compromising the quality of life.

[0016] Conventional vascular assist devices are often configured to increase arterial blood flow from the heart. Generally speaking, many conventional vascular assist devices are both difficult to install and cumbersome for the patient. Several vascular assist devices are configured to be inserted into the vasculature, thereby causing potential infection and other related difficulties. Other devices that are configured to be installed externally to the vasculature include many components that need to be installed in very small areas. Moreover, when the devices need to be adjusted and/or removed, complex procedures are required. Moreover, such devices also are not synchronized with the cardiac cycle, thereby not appropriately timing the compression of the aorta.

SUMMARY OF THE INVENTION

[0017] In light of the previously described problems associated with conventional vascular assist devices, one object of the embodiments of the present invention is to provide a vascular assist device that can be readily implanted within the body of the patient without involving direct blood contact. The device is also readily repositioned and/or removed.

[0018] In one embodiment, there is provided a device including a compliant first layer configured to engage internal vasculature and a second layer coupled to the first layer. The second layer has a stiffness greater than a stiffness of the first layer. The first layer and the second layer define a cavity between them. The cavity has a volume and the first layer is configured to be deformed in response to a change in the volume of the cavity.

[0019] In another embodiment, there is provided a device including an expandable layer configured to engage internal vasculature; and a cover layer coupled to the expandable layer. The cover layer has a length and a width. The expandable layer and the cover layer together define a cavity having a volume. The cover layer defines an opening in fluid communication with the cavity. A reinforcement element is coupled to the cover layer and configured to maintain the length and width of the cover layer. The expandable layer is configured to be selectively deformed in response to a change in the volume of the cavity.

[0020] In another embodiment there is provided a vascular assist device configured to be coupled to at least a portion of a blood vessel including a vascular engaging layer; an expandable layer; and a cover layer. The device has an uninstalled configuration and an installed configuration. The vascular engaging layer is positioned between the outer wall of the blood vessel and the expanding layer. The cover layer and the expanding layer are coupled so as to form a cavity therebetween. The cavity is bounded by the expanding layer and the cover layer. The cover layer has an opening that is in communication with the cavity. The cavity is configured to selectively receive a fluid via the opening. The fluid causes the volume of the cavity to change such that the change in cavity volume causes the expanding layer to deform more than the cover layer to accommodate the change in cavity volume.

[0021] In another embodiment, there is provided a vascular assist device configured to be coupled to at least a portion of a blood vessel. The vascular assist device includes a vascular engaging layer having a first stiffness; a cover layer having a second stiffness that is greater than the first stiffness and being coupled to the vascular engaging layer such that a portion of the cover layer extends past at least a portion of the perimeter of the vascular engaging layer. The cover layer and the vascular engaging layer form a cavity. The cover layer has an opening that is in communication with the cavity. The cavity is configured to selectively receive a fluid via the opening. The device has an uninstalled configuration and an installed configuration.

[0022] In another embodiment there is provided a system that includes a pump having a controller configured to receive a signal associated with the cardiac cycle of a heart and a cuff. The cuff includes a compliant first layer configured to engage internal vasculature; a second layer coupled to the first layer and having a stiffness greater than a stiffness of the first layer and having an opening formed therein. The compliant first layer and the second layer being coupled to form a cavity bounded by the first layer and the second layer. The cavity being in communication with the opening in the second layer. A conduit coupled between the opening and the pump. The conduit is configured to convey a fluid between the pump and the cavity thereby causing deformation of the first layer by expanding and contracting the cavity.

[0023] In another embodiment there is provided a method for augmenting blood flow in a patient body using a cuff formed from a first layer joined to a second layer so that a cavity exists between the layers such that filling the cavity preferentially deforms the first layer. The method includes detecting a first cardiac cycle trigger; porting a fluid into the cavity so as to elastically deform the first layer thereby compressing a blood vessel in response to the first cardiac cycle trigger; and porting a fluid out of the cavity in response to a second cardiac cycle trigger.

[0024] In another embodiment there is provided a method for augmenting blood flow in a body using a cuff formed from a first layer joined to a second layer so that a cavity exists between the layers such that filling the cavity preferentially deforms the first layer. The method includes detecting a cardiac cycle trigger; porting a fluid into the cavity so as to elastically deform the first layer thereby compressing a blood vessel in response to the cardiac cycle trigger; holding the vessel compressed for known duration and porting a fluid out of the cavity at the end of the duration in order to allow the vessel to relax.

[0025] In another embodiment there is provided a method for augmenting blood flow in a vessel of a patient using a cuff having a compliant first layer that at least partially encircles a vessel adjacent the cuff, a second layer coupled to the first layer, the first layer and the second layer defining a cavity. The method includes changing the pressure of a fluid in the cavity based on a signal associated with the cardiac cycle; deforming the first layer in response to the changing pressure of the fluid in the cavity; and deforming the walls of a vessel at least partially encircled by the first layer in response to the deforming of the first layer.

[0026] In another embodiment there is provided a system including a plurality of cuffs, each of the plurality of cuffs including a compliant first layer configured to engage internal vasculature; a second layer coupled to the first layer, the first layer and the second layer defining a cavity therebetween, the second layer defining an opening in communication with the cavity; and a connector configured to couple the plurality of cuffs to one another.

[0027] Another object of the embodiments of the present invention is to provide a method of fabrication and a method of implanting such a vascular assist device.

[0028] A further object of the embodiments of the present invention is to provide a method including increasing a pressure of a liquid or gas in an aortic cuff based on a control signal related to the systole and/or diastole of the heart and/or the aortic pressure.

[0029] Other objects, advantages and features associated with the embodiments of the present invention will become more readily apparent to those skilled in the art from the following detailed description. As will be realized, the invention is capable of other and different embodiments and its several details are capable of modification in various obvious aspects, all without departing from the invention. Accordingly, the drawings and the description are regarded as illustrative in nature, and not limiting.

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present invention is described with reference to the accompanying drawings. In the drawings, like reference numbers indicate similar elements.

[0031] FIG. 1 is a schematic diagram of the ventricular assist device system in accordance with one embodiment of the present invention.

[0032] FIG. 2 is an exploded perspective view of the ventricular assist device in accordance with an embodiment of the present invention.

[0033] FIG. 3 is a perspective view of the device illustrated in FIG. 2 in a first configuration.

[0034] FIG. 4 is a cross-sectional view of the device illustrated in FIG. 3 taken along the line of 5 - 5 in FIG. 3 .

[0035] FIG. 4A is a cross-sectional view of an alternative embodiment of the device illustrated in FIG. 3 .

[0036] FIGS. 5A and 5B are perspective views of alternative configurations of embodiments of the cover layer and expandable layer.

[0037] FIGS. 6A, 6B and 6 C are views of an embodiment of the expandable layer.

[0038] FIG. 7 is a perspective view of a device in accordance with an embodiment of the present invention positioned on the ascending aorta, the device being in a second configuration.

[0039] FIG. 8A is a perspective view of a device in accordance with an embodiment of the present invention positioned in an uninstalled configuration.

[0040] FIG. 8B is a perspective view of the device in FIG. 8A where an embodiment of a material layer is exposed.

[0041] FIG. 9 illustrates another embodiment of the device of FIG. 8A according to the present invention in a second configuration around the ascending aorta.

[0042] FIG. 10 is a perspective view of an device according to an embodiment of the present invention having an embodiment of a vascular engaging layer.

[0043] FIG. 11 is a cross section view of the device of FIG. 10 .

[0044] FIG. 12 illustrates the device of FIG. 10 in an installed configuration about the ascending aorta.

[0045] FIG. 13 illustrates a device of the present invention having an alternative embodiment of the vascular engaging layer in an installed configuration about the ascending aorta.

[0046] FIG. 14A illustrates an embodiment of a segmented cuff according to the present invention in an uninstalled configuration.

[0047] FIG. 14B illustrates a section of the segmented cuff embodiment of FIG. 14A .

[0048] FIGS. 15A and 15B illustrate segmented cuff embodiments of the present invention having embodiments of alternative tab profiles of the present invention.

[0049] FIGS. 16 A- 16 D illustrate perspective and cross section views of alternative segmented cuff embodiments of the present invention.

[0050] FIG. 17 - FIG. 18B illustrate perspective views of alternative segmented cuff embodiments of the present invention.

[0051] FIG. 18C illustrates a cross section view of an embodiment of a conduit of the present invention having a variable diameter.

[0052] FIGS. 19A and 19B illustrate section views of an embodiment of a fluid volume compensator of the present invention.

[0053] FIGS. 19C and 19D illustrate perspective views of alternative embodiments of the vascular assist ssytem of the present invention.

[0054] FIGS. 20 A- 29 illustrate various alternative embodiments of connection mechanisms for the various devices according to the present invention.

[0055] FIG. 30 illustrates an alternative configuration of a device according to the present invention having an alternative embodiment of a fastening system of the present invention.

[0056] FIG. 31 illustrates representative pressure and ECG waves generated by an embodiment of the vascular assist sysstem of the present invention operated in coplusation mode.

[0057] FIG. 32 illustrates representative pressure and ECG waves generated by an embodiment of the vascular assist sysstem of the present invention operated in counterplusation mode.

DETAILED DESCRIPTION

[0058] FIG. 1 illustrates a vascular assist system 100 according to one embodiment of the present invention. In some embodiments, each of the vascular assist system 100 components are implantable within a body. The vascular assist system 100 includes a vascular assist device 200 coupled to a pump 300 via a conduit 225 . The vascular assist device 200 is a fluid inflatable cuff having a cover layer 220 coupled to an expandable layer 210 ( FIG. 4 ). A cavity 250 is defined by the cover layer 220 and the expandable layer 210 ( FIG. 4 ). The vascular assist device 200 is configured to encircle and come into contact with the outer wall of a blood vessel 20 ( FIG. 7 ). One advantage of the embodiments of the vascular assist devices of the present invention is that the devices do not come into contact with the body blood supply (i.e., all vascular assist devices of the present invention remain outside the vasculature being augmented).

[0059] The pump 300 can be any conventional pump but is preferably a pulsatile pump. A conduit 225 (i.e., a hollow flexible tube) connects the pump 300 to the cuff 200 . In an embodiment where the pump 300 is a pulsatile pump, a bladder is commonly disposed within or operably in relation to the pulsatile pump. The bladder is a flexible non-compliant or semi-compliant chamber that stores the fluid used to operate vascular assist device 200 . In operation of the pulsatile pump manipulates the bladder resulting in fluid movement. In another embodiment, a reservoir (not shown) may be provided in communication with the pump. As an alternative to the bladder described above, the reservoir may be used to store fluids used by the vascular assist system 100 for the operation of the vascular assist device 200 .

[0060] Operation of the pump for the activation and de-activation vascular assist device 200 is controlled by the pacing and pump controller 320 . The pacing and pump controller 320 includes a programmable computer and electronics for operating the components of vascular assist system 100 . Sensors 350 , such as, for example, pressure sensors or electronic sensors, are positioned to detect a signal representing the cardiac cycle of a heart in a patient body. A signal representing the cardiac cycle of a heart in a patient body may be, for example, an electrical signal related to the cardiac rhythm, or the blood pressure, such as, in a blood vessel, for example, the aorta or the vena cava or pressure measured elsewhere on the patient body. A battery 310 provides power to the components of the vascular assist system 100 . In the illustrated embodiment, internal coils 322 are also provided so that the battery may be charged transcutaneously.

[0061] In operation, the pacing and pump control 320 may, for example, interpret the signal representing the cardiac cycle detected by the sensors 350 , execute control signals to pump 300 based on the cardiac rhythm to allow fluid into or out of the vascular assist device 200 , record cardiac activity, or execute pre-programmed routines for the actuation of the vascular assist device 200 . For example, to cause compression of a blood vessel, the pacing and pump controller 320 signals the pump 300 to compresses the bladder of the pump (i.e., in the case of a pulsatile pump) thereby forcing the fluid into the cuff 200 resulting in the inflation of the cuff 200 . As will be described in greater detail below, the cuff 200 is positioned in relation to the blood vessel such that cuff inflation results in blood vessel compression. As will be described below, cuff activation and blood vessel compression can be advantageously synchronized with a number of parameters that are related to the cardiac cycle of a heart in a patient body.

[0062] A variety of different type of sensors may be used in vascular assist system 100 for monitoring the cardiac cycle of a heart. In one embodiment, the sensor 350 may be a pressure sensor. One suitable pressure sensor may be, for example, a pressure gage that is coupled (i.e., either integrally coupled or removably coupled) directly to the cuff 200 . Alternatively, the pressure of the blood in a vessel may be measured with a pressure catheter positioned internally within the vessel. In yet another alternative, the sensor 350 may be a pressure transducer suited for measuring blood pressure within a vessel or any portion of the patient body where blood pressure may be detected and used by the system 100 . A suitable pressure transducer may be either internal to or externally disposed about or within the vessel of interest. In an alternative embodiment, the sensor 350 may be an electrical sensor suited for detecting an electrical signal associated with the cardiac cycle of the heart. In some embodiments, the electrical sensor is an electrocardiogram (ECG) lead. It is to be appreciated that some embodiments of the cuff 200 comprise embodiments of the pressure sensor and/or the electrical sensor. The embodiments of the pressure sensor and/or electrical sensor may be disposed directly adjacent the cuff 200 or integrally formed in the cuff 200 .

[0063] As will be described further below, an embodiment of the sensor 350 may be used to detect a signal related to the cardiac cycle of a heart. The signal is then used by the pacing and pump controller, in some embodiments, as the trigger for the activation of the cuff 200 . In one embodiment, the sensor 350 is a pressure sensor and the signal related to the cardiac cycle of the heart is the pressure in a vessel. The vessel measured may also depend on the location of the cuff 200 and the desired augmentation scheme. For example, if arterial augmentation is desired, the cuff 200 will likely be implanted on the arterial side of the heart about the aorta. In this example, the pressure sensor would be disposed to measure aortic pressure. On the other hand, if venous augmentation is desired, the cuff 200 will likely be implanted on the venous side of the heart about the vena cava. In this example, the pressure sensor may be disposed to measure venous pressure in the vena cava (i.e., in either the inferior or superior vena cava) or use a measurement of arterial side pressure.

[0064] The fluid used within the vascular assist system 100 may be any of a wide variety of biocompatible fluids. The system fluid may be a liquid, such as, for example, saline, water, a glycol, such as for example, ethylene glycol. In addition the liquid may also be a mixture comprising water and a glycol or a mixture comprising saline and a glycol. The system fluid may also be a gas such as a gas that is chemically inert with the materials used to form the components in communication with the fluid. Components in communication with the system fluid include, for example, the cuff, 200 , conduit 225 , fluid volume compensator 1900 . For example, when the cuff (i.e., layers 210 and 220 ) is formed from a material such as of silicone, neoprene and copolymers comprising styrene and butadiene then examples of inert gases include carbon dioxide or nitrogen. Alternatively, the system fluid may also be a gas having a density less than air. As used herein, a density less than air refers to a density less than either 1.2928 grams/liter or 0.08071 lb./cu. ft. at a standard temperature and pressure (STP) of 0 degrees C. and 760 mm Hg. Examples of suitable gases having a density less than air are helium (density of 0.1785 grams/liter or 0.01143 lb./cu. ft.); and nitrogen (density of 1.2506 grams/liter or 0.078072 lb./cu. ft.).

[0065] FIGS. 2, 3 , and 4 illustrate a first embodiment of the ventricular assist device 200 of the present invention. The device 200 includes a compliant first layer or expandable wall 210 that is configured to be coupled to a second layer or cover layer 220 such that a cavity 250 is defined between the first layer 210 and the second layer 220 ( FIGS. 3 and 4 ). The second layer or cover layer 220 includes an opening 222 for fluid access to the cavity 250 , mechanical connection for fluid system via connection 230 , a semi-rigid support base for cavity 250 and expandable wall 210 and mechanical support for the fasteners and/or cuff closure system 280 FIGS. 2, 3 , 4 and 7 ).

[0066] In some embodiments, the first layer 210 is coupled to the second layer 220 about a perimeter of the first layer 210 . In other embodiments, the first layer 210 is coupled to the second layer 220 about a portion of the perimeter of the second layer 220 . In another embodiment, a perimeter of the second layer 220 extends beyond the perimeter of the first layer 210 . The expandable layer 210 and cover layer 220 could also be thought of, relative to the vasculature, as in inner layer (expandable layer 210 ) and an outer layer (cover layer 220 ). Alternatively, the inner layer 210 can be coupled to the outer layer 220 about a perimeter of the inner layer 210 . In another embodiment, a perimeter of the outer layer 220 extends beyond the perimeter of the inner layer. Alternatively, the outer layer 220 can include a first edge, a second edge, a third edge and a fourth edge. At least one of the edges can be collocated with an edge along the perimeter of the inner layer 210 .

[0067] The cover layer or second layer 220 includes a length and a width and the first layer or expandable layer 210 also includes a length and a width. In some embodiments of the device 200 , the length of the first layer 210 is less than the length of the second layer 220 . In another embodiment of the device 200 , the width of the first layer 210 is less than the width of the second layer 220 . In another embodiment, the length of the first layer 210 is sufficient for the first layer 210 to partially completely encircle a portion of a blood vessel. The length of the first layer 210 may be long enough to partially encircle, for example, a portion of the ascending aorta, the descending aorta, the superior vena cava, the inferior vena cava or a portion of a blood vessel that also includes a set of intercostal arteries or a set of intercostals veins.

[0068] In another embodiment, the length of the second layer 220 is sufficient for the second layer 220 to completely encircle a portion of a blood vessel. The second layer 220 may also include a fist end and a second end. When the second layer 220 is configured to completely encircle a portion of a blood vessel, the first end and the second end of the second layer overlap. The length of the second layer 220 may be long enough to encircle, for example, a portion of the ascending aorta, the descending aorta, the superior vena cava, the inferior vena cava or a portion of a blood vessel that also includes a set of intercostals arteries or a set of intercostals veins. The length of the second layer 210 is configured to partially encircle a blood vessel when installed about a blood vessel.

[0069] The cover layer 220 also includes at least one opening 222 in fluid communication with the cavity 250 ( FIGS. 2 and 4 ). The cuff 200 includes a port 230 that can be coupled to the conduit 225 to deliver fluid to the cavity 250 . The second layer 220 defines an opening 222 to provide fluid access to the cavity 250 . A coupling 230 is provided to couple the conduit 225 to the opening 222 in the second layer 220 ( FIGS. 2 and 4 ). The conduit 225 is coupled to the second layer or cover layer 220 in communication with the opening 222 . The conduit 225 is configured to be coupled to the pump 300 . As such, the conduit 225 and the fluids therein are in fluid communication with the cavity 250 . In response to fluid pressure changes and/or volume changes of the cavity 250 , the compliant first layer 210 is configured to deform (i.e., expand in response to increasing pressure or volume of the cavity 250 ). When the vascular assist device 200 is installed about a blood vessel (i.e., FIG. 7 ), the first layer 210 at least partially encircles the blood vessel. The pump and pacing controller 320 directs the pump 300 to supply fluid to the device 200 in response to and in synchronization with a signal representing the cardiac cycle of a heart in a patient body. Fluid then enters the cavity 250 causing it to increase in volume and/or pressure thus deforming the expandable wall 210 . As the first layer 210 deforms (under pressure of the expanding cavity 250 ), the vessel encircled by the cuff 200 is compressed and blood within the vessel is urged onward. As such, the fluid (i.e., the gas or the liquid) is configured to be selectively communicated in synchronization with the cardiac cycle to the cavity 250 via a conduit 225 in communication with the opening 222 in the cover layer 220 .

[0070] Embodiments of the vascular assist device of the present invention provide a compliant first layer 210 that is configured to engage internal vasculature. The second layer or cover layer 220 is coupled to the first layer 210 defining a cavity 250 . The second layer 220 has a stiffness greater than a stiffness of the first layer 210 . In response to changing volume of cavity 250 , the first layer is configured to be deformed in response to a change in the volume of the cavity 250 . Additionally, the first layer 210 is deformable such that when the pressure inside the cavity 250 increases, the first layer 210 deforms (i.e., expands). The second layer or cover layer 220 is configured to be flexible enough to encircle a blood vessel however, rigid enough not to deform under the range of pressures and volumes experienced by the cavity 250 . Through the advantageous selection of the flexibility of the cover layer 220 and the expandable layer 210 , the changes in fluid pressure or cavity volume are more likely to deform the expandable wall 210 and result in compression of the vessel of interest.

[0071] The advantageous functioning the cover layer and the expandable layer may be accomplished, for example, through selection of the materials selected for each of the layers. The expandable layer material may be selected to have a stiffness less than the stiffness of the cover layer. The expandable layer 210 may be fabricated with a first material and the cover layer 220 may be fabricated with a second material. In some embodiments, the first material is a first silicone elastomer and the second material is a second silicone elastomer. The first silicone elastomer may be a 5-50 A silicone elastomer having a minimum of 500% elongation. The second silicone elastomer is a 65-95 A silicone elastomer having less than a 400% elongation. In an alternative embodiment, the first material may be an elastomer having a hardness of 5-50 shore A and a minimum elongation of 500%. The second material may be an elastomer having a hardness of 65-95 shore A and a maximum elongation of 400%.

[0072] To maximize the efficiency of the device 200 , the cover or second layer 220 is configured to be flexible, but does not stretch or expand under the pressure inside the cavity 250 . The first layer or inner layer 210 is made of a more flexible (i.e., less stiff) material than the cover layer 220 . In one particular embodiment, the inner wall or first layer 210 can be made of a 5 to 50 A silicone elastomer with a minimum of 500% elongation and the outer or cover layer 220 can be made out of less compliant silicone such as a 65 to 95 A silicone elastomer with less than 400% elongation. The first and second layers may, for example, be formed from a material that is one of silicone, neoprene and copolymers comprising styrene and butadiene. In some embodiments, the outer layer 220 is fabricated in the same manner as the first layer 210 and can be attached to the inner layer 210 by adhesives such as silicone RTV. The outer layer 220 can also be over-molded on the inner layer 210 by insert molding.

[0073] Other suitable materials for the cuff 200 (i.e., suitable materials for the layers 210 and 220 ) include C-Flex™, santoprene, Kraton™, PVDF, etc. Possible fabrication methods include injection molding, casting, dip molding, insert molding, over molding and blow molding. Kraton™ and C-Flex™ refer generally to thermoplastic elastomers (TPE's) that are copolymers of styrene, butadiene, and other polymers which range in hardness from 5 shore A durometer to 95 shore A durometer. C-Flex™ is commercially available from, for example, Consolidated Polymer Technologies, Inc. (CPT) of Clearwater, Fla. Kraton™ is commercially available from, for example, GLS Corporation of Delaware. Both Kraton™ and C-Flex™ are desirable materials because of their high bio-compatibility, high modulus of elasticity, and easy fabrication.

[0074] To improve the performance and durability of the cuff 200 , the layers 210 , 220 and other components in vascular assist system 100 may each be reinforced by an additional material or a reinforcement element. Reinforcement, as used herein, includes the addition of a reinforcing element to a material to prevent rupture, prevent crushing, or adjust the material properties of the material. Examples of how reinforcing elements may be used to alter the material properties of a material include the addition of reinforcing elements to alter the elongation properties of a material, reduce the permeability of a material or improve the strength of a material. In one illustrative embodiment, the second layer or cover layer includes a reinforcement element. The reinforcement element is coupled to the cover layer and configured such that the reinforcement element maintains the length and width of the cover layer as fluid is ported into and out of the cavity 250 . As such, the reinforcing element is used to maintain the rigidity of the cover layer 250 so that the desired deformation of the layer 210 occurs. In this regard, the cover layer 250 provides mechanical strength for the advantageous deformation of the expanding layer 220 .

[0075] In addition, the reinforcing element or elements may be incorporated into the material such that material reinforcement is selective and adjustable. Representative reinforcing materials include polyester, nylon, para-aramid fiber, stainless steel, platinum, superelastic nitinol and alloys of nickel and titanium. The para-aramid fiber may be commercially available, such as, for example, Kevlar™, and/or polyester fibers. Alternatively, reinforcement may accomplished by simply adjusting the wall thickness a component to that the thicker wall portions of the component act as reinforcing elements. The conduits 225 , 228 may also employ reinforcing elements so that the walls of the conduit do not collapse under pressure of tissue growth within the body.

[0076] The use of fiber reinforcement elements for the cover layer and/or expandable layers 210 , 220 of the device 200 may also reduce the permeability of the layers 210 , 220 , thus reducing fluid loss through the walls. Additionally, to minimize fluid loss of the vascular assist system 100 the surfaces of the pump 300 , cuff 200 and conduit 225 in contact with the fluid used in the system 100 may be coated with impermeable or semi-permeable materials such as polyethylene, polypropylene, etc. Alternatively, the inside surfaces (i.e., surfaces not in direct contact with the patient body) and/or outside surfaces (i.e., surfaces in direct contact with the patent body) of embodiments of the cuff 200 , pump 300 , conduits 225 , 228 and the fluid volume compensator 1900 may be coated with impermeable or semi-permeable materials such as polyethylene, polypropylene, etc. to reduce fluid loss from the system 100 . Metallic powder coatings can also be used for the same purpose.

[0077] The cover layer or second layer 220 extends beyond the chamber or cavity 250 , thereby creating a flexible overlapping set of flaps 270 . As described above the cover layer 220 provides an opening 222 and mechanical support for the attachment of coupling 230 . In some embodiments of the vascular assist device 200 , the cover layer 220 also provides the mechanical attachment point for the fastening means 280 used to secure the vascular assist device 200 about a portion of a vessel. In other embodiments, the vascular assist device 200 is configurable between an uninstalled configuration (i.e., when the fastening means 280 are not coupled, FIGS. 2, 3 and 4 ) and an installed configuration when the fastening means 280 are coupled (i.e., FIG. 7 ). In the illustrated embodiments, the cuff 200 is configurable between a first, planer configuration ( FIGS. 2, 3 and 4 ) and a second configuration in which it is tubular or oval in shape and configured to be positioned around a blood vessel (i.e., a portion of the ascending aorta 20 as in FIG. 7 ). It is to be appreciated that other embodiments of the vascular assist device 200 are possible where both the first and second configurations are generally tubular and the difference between the first and second configurations depends on whether or not the fastening elements are coupled (second configuration) or uncoupled (first configuration).

[0078] The device 200 is held in position about a vessel by fastening elements 280 . The flaps 270 can support the fastening elements 280 for the device 200 ( FIGS. 2, 3 and 4 ). The fastening elements 280 have cooperatively configured ends 282 and 284 . In the illustrated embodiment, one end 282 has a feature 285 configured to be cooperatively coupled to one of the plurality of features 286 on end 284 . When the device 200 is configured about a vessel, the ends 282 , 284 may be adjustably and repeatably fastened. The device 200 is adjustably fastened because the feature 285 on end 282 may be coupled to any one of the features 286 depending upon the size (i.e., external diameter) of the vessel. The device 200 is repeatably fastened because the cooperative fastening elements 285 , 286 may be coupled and uncoupled repeatably. The embodiments of the vascular assist device having the adjustable and repeatable features may advantageously be employed for a wide variety of vessel sizes (i.e., diameter). A physician implanting the device 200 may install (i.e., secure about a vessel of interest) and test (i.e., activate the device