`(12) Patent Application Publication (10) Pub. No.: US 2004/0054348A1
`Hogendijk
`(43) Pub. Date:
`Mar. 18, 2004
`
`US 2004.0054348A1
`
`(54) CATHETER HAVING ACOMPLIANT
`MEMBER CONFIGURED TO REGULATE
`ASPIRATION RATES
`
`(76) Inventor: Me Hogendijk, Palo Alto, CA
`
`Correspondence Address:
`NICOLA A. PISANO, ESQ.
`LUCE, FORWARD, HAMILTON & SCRIPPS
`LLP
`11988 EL CAMINO REAL
`SUTE 200
`SAN DIEGO, CA 92130 (US)
`(21) Appl. No.:
`10/243,525
`
`(22) Filed:
`
`Sep. 12, 2002
`
`Publication Classification
`
`(51) Int. Cl." .................................................... A61M 25/00
`(52) U.S. Cl. ............................................ 604/523; 604/118
`(57)
`ABSTRACT
`The present invention is directed to a catheter that is
`configured to Self-regulate aspiration rates through a work
`ing lumen of the catheter. The catheter comprises a compli
`ant member in communication with the working lumen that
`is configured to transition from an open position to a closed
`position when a predetermined aspiration threshold is
`exceeded. In the closed position, the compliant member is
`temporarily drawn inward to at least partially occlude flow
`through the working lumen, thereby mitigating the rate of
`aspiration imposed upon a patient's vessel. When the rate of
`aspiration is reduced below the threshold level, the compli
`ant member returns to the open position.
`
`
`
`Page 1
`
`
`
`IPR2020-00126/-127/-128/-129/-130/-132/-134/-135/-136/-137/-138
`
`Medtronic Ex-1810
`Medtronic v. Teleflex
`
`
`
`Patent Application Publication Mar. 18, 2004 Sheet 1 of 6
`
`US 2004/0054348A1
`
`
`
`Page 2
`
`
`
`Patent Application Publication Mar. 18, 2004 Sheet 2 of 6
`
`US 2004/0054348A1
`
`Vy
`NS
`
`
`
`Page 3
`
`
`
`Patent Application Publication Mar. 18, 2004 Sheet 3 of 6
`
`US 2004/0054348A1
`
`
`
`Page 4
`
`
`
`Patent Application Publication Mar. 18, 2004 Sheet 4 of 6
`
`US 2004/0054348A1
`
`
`
`Page 5
`
`
`
`Patent Application Publication Mar. 18, 2004 Sheet 5 of 6
`
`US 2004/0054348A1
`
`
`
`7 777 - ZZZ ZZ ZZ 4 ZZZ
`
`Page 6
`
`
`
`Patent Application Publication Mar. 18, 2004 Sheet 6 of 6
`
`US 2004/0054348A1
`
`AAAAAAYAA-AAAS AA-N-YAS, NARAA.
`2KE2K2223222 2.x 3XYZ X X
`ZZZZZZZ 1444 ZZZZ
`
`an
`
`
`
`
`
`
`
`relate 222 re-left
`
`CAMAAAACAOVAVAVAACVOYAVCYvVAYAT
`
`PAAs A A Ye AAA-AA-AA-AA-AAYYANAAA
`
`Page 7
`
`
`
`US 2004/0054348A1
`
`Mar. 18, 2004
`
`CATHETER HAVING ACOMPLIANT MEMBER
`CONFIGURED TO REGULATE ASPIRATION
`RATES
`
`FIELD OF THE INVENTION
`0001. The present invention relates to apparatus and
`methods for regulating rates of aspiration during a medical
`procedure, and more Specifically, a catheter that Self-regu
`lates aspiration rates through a working lumen of the cath
`eter.
`
`BACKGROUND OF THE INVENTION
`0002 Today there is a growing need to provide controlled
`access and vessel management during Such procedures as
`Stenting, atherectomy or angioplasty. Generally, during these
`procedures there is a high opportunity for the release of
`embolic material. The emboli may travel downstream from
`the occlusion, lodging deep within the vascular bed and
`causing ischemia. The resulting ischemia may pose a Serious
`threat to the health or life of a patient if the blockage forms
`in a critical area, Such as the heart, lungs, or brain.
`0003. Several previously known methods and apparatus
`incorporate the use of an external Suction System in con
`junction with an aspiration catheter for removal of clots,
`removal of embolic particles, or general flow management
`in a vessel. However, there are Several risks associated with
`using an external Suction System during Such medical inter
`ventions.
`0004 For example, if the amount of Suction is too high,
`trauma may be imposed upon the vessel, resulting in vessel
`dissections or Spasms. Additionally, an excessively high rate
`of aspiration may facilitate clot formation within the vessel.
`Moreover, if an external Suction pump is utilized, exces
`Sively high aspiration rates may result in excessive blood
`loSS, requiring infusion of non-autologous blood and raising
`related Safety issues.
`0005 Traditional methods for regulating aspiration rates
`used with Suction pumps have relied on external preSSure
`adjustments, e.g., requiring physician monitoring of the
`Suction rates, which may lead to an incorrect amount of
`Suction for a given Set of circumstances and present risk of
`the above-mentioned complications. Previously-known
`Safety mechanisms, Such as relief Valves, have been
`employed and typically are coupled to the proximal end of
`the catheter. However, Such features may require additional
`parts or assembly to regulate flow.
`0006. In view of these drawbacks of previously known
`Systems, it would be desirable to provide apparatus and
`methods for Self-regulating aspiration rates through a work
`ing lumen of a catheter to reduce trauma imposed upon a
`patient's vessel.
`0007. It also would be desirable to provide apparatus and
`methods that regulate aspiration rates using a mechanism
`that is an inherent feature of the catheter, to eliminate the
`need for continuous aspiration monitoring with the potential
`for human error.
`0008. It further would be desirable to provide apparatus
`and methods that reduce the likelihood of kinking when the
`catheter comprises a compliant member configured to regu
`late flow.
`
`0009. It still further would be desirable to provide appa
`ratus and methods for Self-regulating aspiration rates that
`may be tailored for use in Specific applications, e.g., cerebral
`and cardiovascular interventions.
`
`SUMMARY OF THE INVENTION
`0010. In view of the foregoing, it is an object of the
`present invention to provide apparatus and methods for
`Self-regulating aspiration rates through a working lumen of
`a catheter to reduce trauma imposed upon a patient's vessel.
`0011. It is also an object of the present invention to
`provide apparatus and methods that regulate aspiration rates
`using a mechanism that is an inherent feature of the catheter,
`to eliminate the need for continuous aspiration monitoring
`with the potential for human error.
`0012. It is a further object of the present invention to
`provide apparatus and methods that reduce the likelihood of
`kinking when the catheter comprises a compliant member
`configured to regulate flow.
`0013. It is yet another object of the present invention to
`provide apparatus and methods for Self-regulating aspiration
`rates that may be tailored for use in Specific applications,
`e.g., cerebral and cardiovascular interventions.
`0014. These and other objects of the present invention are
`accomplished by providing a catheter having proximal and
`distal ends and a working lumen extending therebetween.
`The catheter comprises a compliant member having an open
`position, whereby fluid flow through the working lumen is
`not Substantially constrained, and a closed position whereby
`fluid flow through the working lumen is at least partially
`occluded. The compliant member is transformed from the
`open position to the closed position when a predetermined
`degree of Suction is applied to the working lumen. In the
`closed position, the compliant member Serves to occlude
`flow through the working lumen and mitigate the rate of
`aspiration imposed upon a patient's vessel.
`0015. In a preferred embodiment, a catheter provided in
`accordance with the present invention comprises a compli
`ant Section disposed between two relatively rigid Sections.
`The compliant Section comprises a polymer cover and the
`compliant member, which is in communication with the
`working lumen. The relatively rigid Sections preferably
`comprise the polymer cover, a wire braid and an inner layer,
`which is in communication with the working lumen. The
`relatively rigid Sections are leSS compliant than the compli
`ant Section due to the presence of the wire braid. An inner
`surface of the compliant member is substantially flush with
`an inner Surface of the inner layer to facilitate a Substantially
`undisturbed fluid flow through the working lumen.
`0016. The catheter of the present invention may be
`coupled to a Suction-assisted aspiration device, e.g., a
`Syringe, or may be used in conjunction with other aspiration
`techniques described hereinbelow. When the level of aspi
`ration provided through the working lumen is at an accept
`able rate, i.e., induced by a level of Suction that will not
`impose significant trauma upon a patient's vessel, the com
`pliant member remains in the open position and does not
`impede fluid flow through the working lumen.
`0017 When a predetermined aspiration threshold is
`exceeded, however, the rigidity of the compliant member is
`
`Page 8
`
`
`
`US 2004/0054348A1
`
`Mar. 18, 2004
`
`overcome, thereby causing the compliant member to trans
`form to the closed position. The compliant member is
`temporarily drawn inward to at least partially occlude flow
`through the working lumen and impede aspiration from the
`patient's vessel. When the level of suction falls below the
`threshold level, the compliant member returns to the open
`position.
`0.018
`Advantageously, the self-regulating compliant
`member of the present invention is a feature that may be
`built directly into the catheter, thus alleviating the need to
`assemble additional components. Alternatively, the valve
`may be constructed as a separate add-in piece. Additionally,
`the catheter may be tailored for use for a particular appli
`cation, e.g., cerebral and cardiovascular interventions, by
`varying the material properties or configuration of the com
`pliant member, which in turn varies the aspiration threshold
`for which the compliant member is actuated.
`0.019
`Apparatus and methods also are disclosed to reduce
`the likelihood of kinking associated with the use of a
`compliant catheter Section. During insertion of the catheter,
`a dilator preferably is used to enhance pushability of the
`catheter. Additionally, a reinforcement sheath may be
`employed to enclose the compliant Section. In this embodi
`ment, a proximal end of the reinforcement sheath is affixed
`to a first relatively rigid catheter Section, and a distal end of
`the reinforcement sheath is affixed to a Second relatively
`rigid catheter Section. The compliant Section is disposed
`between the first and Section relatively rigid Sections and is
`not affixed to the reinforcement sheath. This allows the
`compliant Section to be drawn inward to occlude the work
`ing lumen, while enhancing Structural integrity in the vicin
`ity of the compliant Section.
`0020. The compliant section preferably is disposed
`within a proximal region of the catheter, i.e., a region that is
`not introduced into a patient's body. This reduces the
`likelihood of kinking because the compliant Section is not
`required to be advanced through a patient's tortuous vascu
`lature. However, it will be apparent to one of skill in the art
`that the compliant member may be disposed at any region
`along the length of the catheter.
`0021. In an alternative embodiment of the present inven
`tion, the compliant member comprises a compliant sheath
`affixed to an inner layer of the catheter. The compliant sheath
`is affixed at first and Second ends to the inner layer and
`remains in an open position, whereby the compliant sheath
`does not Substantially impede flow through the working
`lumen, when an acceptable rate of aspiration is applied.
`When an aspiration threshold is exceeded, however, the
`compliant sheath is drawn inward to at least partially
`occlude flow through the working lumen and mitigate the
`rate of aspiration imposed upon a patient's vessel.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`0022. Further features of the invention, its nature and
`various advantages will be more apparent from the accom
`panying drawings and the following detailed description of
`the preferred embodiments, in which:
`0023 FIG. 1 provides a side view of a previously-known
`catheter assembly;
`0024 FIG. 2 provides a cross-sectional view along line
`A-A of FIG. 1;
`
`0025 FIG.3 provides a side view of a catheter assembly
`constructed in accordance with principles of the present
`invention;
`0026 FIG. 4 provides a cross-sectional view along line
`B-B of FIG. 3;
`0027 FIGS.5A-5B are, respectively, side sectional views
`illustrating a compliant member of the present invention in
`open and closed positions,
`0028 FIGS. 6A-6B illustrate the device of FIG.5 further
`comprising a reinforcement sheath to enhance Structural
`integrity;
`0029 FIGS. 7A-7B are, respectively, side sectional views
`illustrating a compliant member of the present invention,
`which is disposed at the distal end of a catheter, in open and
`closed positions, and
`0030 FIGS. 8A-8B describe an alternative embodiment
`of the present invention having a compliant sheath affixed to
`an inner layer of a catheter.
`
`DETAILED DESCRIPTION OF THE
`INVENTION
`0031. The present invention is directed to a catheter that
`is configured to regulate aspiration rates through a working
`lumen of the catheter. The catheter comprises a compliant
`member in communication with the working lumen that
`transitions from an open position to a closed position when
`a predetermined level of aspiration is applied. In the closed
`position, the compliant member is drawn inward to at least
`partially occlude flow through the working lumen, thereby
`reducing the rate of aspiration provided through the working
`lumen and mitigating the rate of aspiration imposed upon a
`patient's vessel. When the rate of aspiration is reduced
`below the threshold level, the compliant member returns to
`the open position to reestablish an unimpeded flow through
`the working lumen.
`0032 Referring to FIG. 1, a previously known catheter
`assembly, described in applicant's commonly-assigned U.S.
`Pat. No. 6,423,032, is shown. Catheter assembly 20 com
`prises catheter 21 having proximal and distal ends and
`working lumen 23 extending therebetween. Catheter 21 also
`comprises occlusive element 22 disposed on the distal end,
`as shown in FIG. 1. Catheter 21 is coupled to proximal
`assembly 24, which may include inflation port 25, hemo
`Static port 26, e.g., a Touhy-Borst connector, and blood
`outlet port 27, each of which are in fluid communication
`with working lumen 23. Blood outlet port 27 may allow for
`either natural aspiration, using techniques described herein
`below, or Suction-assisted aspiration, e.g., using a Syringe.
`0033 Referring to FIG. 2, a cross-sectional view along
`line A-A of FIG. 1 is provided. Catheter 21 preferably
`comprises inner layer 40 of low-friction material, Such as
`polytetrafluoroethylene (“PTFE), covered with a layer of
`flat stainless Steel wire braid 41 and polymer cover 42 (e.g.,
`polyurethane, polyethylene, or PEBAX). Inflation lumen 43
`is disposed within polymer cover 42 and couples inflation
`port 25 to occlusive element 22. Catheter 41 may be
`configured for use in coronary, cerebral, or other vascular
`interventions.
`0034.
`In operation, catheter 21 preferably is advanced
`over a guidewire and dilator (not shown), using techniques
`
`Page 9
`
`
`
`US 2004/0054348A1
`
`Mar. 18, 2004
`
`that are per Se known in the art. Catheter 21 is positioned in
`a Selected vessel and occlusive element 22 is deployed via
`inflation port 25 to occlude antegrade flow in the vessel.
`Blood outlet port 27, which is in fluid communication with
`working lumen 23, may be coupled to an external aspiration
`device, e.g., a Syringe, to cause blood flow distal of occlu
`Sive element 22 to flow in a retrograde fashion into working
`lumen 23. Alternatively, blood outlet port 27 may be coupled
`to a venous return sheath (not shown) to form an arterial
`venous shunt Suitable for providing retrograde flow in a
`treatment vessel. This aspiration embodiment comprising an
`arterial-venous shunt is described in detail in applicant's
`above-referenced patent.
`0035. As described hereinabove, the provision of Suction
`assisted aspiration through blood outlet port 27, e.g., to
`assist in the removal of emboli formed in a vessel during an
`interventional procedure performed through working lumen
`23, poses significant risks to the vessel. First, it may be
`difficult to establish the proper aspirating pressure required
`at the treatment Site, and external pressure adjustments used
`with Suction pumps may lead to an incorrect amount of
`Suction for a given set of circumstances. If the amount of
`Suction is too high, the vessel may collapse or excessive
`blood loSS may result. Accordingly, there is a need for a
`catheter having an inherent feature to prevent excessive rates
`of aspiration from being imposed upon a patient's vessel,
`particularly during the removal of emboli from the vessel.
`0.036
`Referring now to FIG. 3, apparatus constructed in
`accordance with a first embodiment of the present invention
`is described. Apparatus 60 preferably is provided substan
`tially in accordance with apparatus 20 of FIG. 1, with the
`exception that catheter 61 having proximal and distal ends
`comprises compliant Section 73 having compliant member
`74. While compliant section 73 is illustratively depicted as
`being disposed in a central region of catheter 61, compliant
`section 73 may be disposed at the proximal or distal end of
`catheter 61, as described hereinbelow.
`0037 Referring to FIG. 4, a cross-sectional view along
`line B-B of FIG. 3 is provided. Compliant section 73
`preferably comprises polymer cover 70 (e.g., polyurethane,
`polyethylene, or PEBAX) and compliant member 74. Infla
`tion lumen 83 is disposed within polymer cover 70 and
`couples inflation port 65 to occlusive element 62. Compliant
`member 74 preferably is attached to an inner surface of
`polymer cover 70 and preferably comprises a tubular shape,
`as shown in FIG. 4. Working lumen 63, which is in fluid
`communication with blood outlet port 67 and hemostatic
`port 66 of FIG. 3, also is in communication with compliant
`member 74.
`0038) Referring now to FIG. 5, a side sectional view
`illustrating the inventive features of compliant section 73 are
`described. Compliant section 73 preferably is disposed
`between two relatively rigid catheter sections 72. Relatively
`rigid Sections 72 preferably are provided in accordance with
`catheter 21 of FIGS. 1-2 and comprise inner layer 80 of
`low-friction material, Such as polytetrafluoroethylene
`(“PTFE), covered with a layer of flat stainless steel wire
`braid 81 and polymer cover 70, which preferably is the same
`cover that is affixed to an outer Surface of compliant member
`74, as shown in FIG. 5A. Inflation lumen 83 of FIG. 4
`(which is not shown in FIG.5A) is disposed within polymer
`cover 70 and spans the length of catheter 61.
`
`0039 Inner layer 80 and wire braid 81 preferably are
`disposed adjacent compliant member 74 at proximal and
`distal locations 87 and 88. Compliant section 73 is more
`compliant relative to sections 72 due to the absence of wire
`braid 81. Compliant member 74 preferably is sized to
`replace a void created by the absence of inner layer 80 and
`wire braid 81 between proximal and distal locations 87 and
`88. An outer Surface of compliant member 74 preferably is
`affixed to an inner surface of polymer cover 70, while inner
`surface 78 of compliant member 74 is substantially flush
`with inner surface 79 of inner layer 80, as shown in FIG.5A.
`This provides a Substantially SeamleSS transition between
`sections 72 and 73 to facilitate flow through working lumen
`63.
`0040. In accordance with principles of the present inven
`tion, compliant member 74 comprises a material having
`properties that are more compliant than the combination of
`inner layer 80 and wire braid 81. This allows compliant
`section 73, which includes polymer cover 70 and compliant
`member 74, to be more compliant overall than section 72,
`which includes having polymer cover 70, wire braid 81 and
`inner layer 80.
`0041. During operation, aspiration may be provided
`through working lumen 63, and blood and/or emboli may be
`aspirated through working lumen 63 via blood outlet port 67
`of FIG. 3, as described hereinabove. Also, an interventional
`procedure, Such as balloon angioplasty or Stenting, may be
`performed through working lumen 63 and hemostatic port
`66 of FIG. 3.
`0042. When the rate of aspiration provided through work
`ing lumen 63 via blood outlet port 67 is appropriate, i.e., at
`Such a rate that the aspiration generally will not cause
`damage to a patient's vessel, then compliant member 74
`remains in an open position, as shown in FIG. 5A. This is
`because the aspiration force provided through the working
`lumen is not yet Sufficient to overcome the resistance force
`inherent to compliant member 74. In the open position, fluid
`flow through working lumen 63 is not substantially con
`strained, as shown in FIG. 5A.
`0043. However, when the aspiration provided through
`working lumen 63 is increased above a predetermined
`threshold, i.e., at a rate So high as to generally cause damage
`to a patient's vessel (distal of occlusive member 62), then
`compliant member 74 is transformed from the open position
`of FIG. 5A to a closed position, as shown in FIG. 5B.
`Compliant member 74 is automatically drawn inward when
`the aspiration rate provided through working lumen 63 is
`Sufficient to overcome the resistance force provided by
`compliant member 74. In the closed position, compliant
`member 74 is drawn inward to at least partially occlude flow
`through working lumen 63. Compliant member 74 may fully
`occlude working lumen 63 when the aspiration threshold is
`exceeded, as depicted in FIG. 5B, or alternatively may
`partially occlude working lumen 63 an amount proportional
`to the excessive rate of aspiration.
`0044. By causing compliant member 74 of compliant
`Section 73 to at least partially occlude flow through working
`lumen 63, the rate of aspiration provided through working
`lumen 63 is reduced. This serves to mitigate the rate of
`aspiration imposed upon a patient's vessel and may reduce
`the risk of damage to the vessel that may be caused by an
`excessive rate of aspiration. When the level of aspiration
`
`Page 10
`
`
`
`US 2004/0054348A1
`
`Mar. 18, 2004
`
`applied through working lumen 63 falls below the threshold,
`then compliant member 74 returns to the open position
`shown in FIG. 5A to reestablish regular flow through
`working lumen 63.
`0.045. In accordance with principles of the present inven
`tion, catheter 61 of the present invention reduces the like
`lihood of damage to a vessel from applying too much
`aspiration by automatically mitigating the rate of aspiration
`when it exceeds a predetermined threshold. Advantageously,
`this Self-regulating mechanism may be provided as a built-in
`feature of the catheter, and thus eliminates the need for
`continuous aspiration monitoring with the potential and the
`attendant risk of human error.
`0046. As will be appreciated by those skilled in the art,
`the aspiration threshold for which compliant member 74 is
`drawn inward to occlude working lumen 63 may be deter
`mined by varying the characteristics of compliant member
`74. For example, when compliant member 74 is manufac
`tured of a more rigid material, then a higher rate of aspiration
`may be required to draw compliant member 74 into the
`working lumen. When compliant member 74 is manufac
`tured of a less rigid material, a lower rate of aspiration is
`required to transform compliant member 74 between the
`open position of FIG. 5A and the closed position of FIG.
`5B.
`0047. Additionally, the aspiration threshold for which
`compliant member 74 is drawn into working lumen 63 may
`be varied by varying longitudinal length X of compliant
`member 74. When length X is greater, a lower rate of
`aspiration may be required to draw compliant member 74
`into working lumen 63 relative to the rate required when
`length X is Smaller.
`0.048. The aspiration threshold for which compliant
`member 74 is drawn into working lumen 63 may be pre
`defined for Specific medical interventions. For example,
`when catheter 61 is intended for use in conjunction with
`cerebral interventions, the predefined aspiration threshold
`may be relatively low to cause compliant member to miti
`gate aspiration rates as they become moderate or high,
`whereas a different threshold may be desired during cardio
`vascular interventions.
`0049. Although compliant section 73 is illustratively dis
`posed in a central region of catheter 61 in FIG. 3, it may be
`preferable to dispose compliant section 73 within proximal
`region 76 (shown in FIG. 3), i.e., a proximal catheter region
`that is not introduced into a patient's vasculature. By dis
`posing compliant Section 73 in a proximal region that
`remains outside of a patient's body, the likelihood of kinking
`may be reduced because the compliant Section is not
`advanced through a patients tortuous vasculature. It should
`be noted that, even when compliant section 73 is disposed in
`a central or distal region, kinking is not expected to occur
`when a dilator (not shown) is used in conjunction with
`catheter 61 during insertion of the catheter.
`0050 Referring now to FIG. 6, reinforcement sheath 90
`having proximal and distal ends 91 and 92 may be used in
`conjunction with compliant section 73 of the embodiment of
`FIG. 5 to further reduce the likelihood of kinking in the
`vicinity of compliant section 74. As shown in FIG. 6A,
`proximal end 91 of reinforcement sheath 90 is affixed to a
`first relatively rigid section 72 and distal end 92 is affixed to
`
`a Second relatively rigid Section 72. Reinforcement sheath
`90 comprises a material that is more rigid than the combi
`nation of polymer cover 70 and compliant member 74, to
`help reduce kinking in the vicinity of compliant Section 73.
`0051 A central region of reinforcement sheath 90
`encloses compliant section 73 but is not affixed to section
`73, to allow compliant member 74 to be drawn into working
`lumen 63 when an aspiration threshold is exceeded, as
`shown in FIG. 6B. A diameter of the central region of
`reinforcement sheath 90 preferably is sized to be slightly
`larger than an outer diameter of catheter 61. Proximal and
`distal ends 91 and 92 further preferably comprises proximal
`and distal tapers, as depicted, to facilitate insertion of
`catheter 61.
`0.052
`Referring now to FIG.7, catheter 100 preferably is
`provided in accordance with catheter 61 of FIGS. 3-5, with
`the exceptions that compliant Section 101 having compliant
`member 104 is disposed at the distal end of catheter 100 and
`occlusive element 62 is omitted. Compliant section 101
`having compliant member 104 and polymer cover 110 is
`disposed distal of relatively rigid section 102 having inner
`layer 112, wire braid 111 and polymer cover 110. As
`described with respect to the embodiment of FIGS. 3-5, an
`outer surface of compliant member 104 preferably is affixed
`to polymer cover 110, while a first end of compliant member
`104 is affixed to inner layer 112 and/or wire braid 111 of
`relatively rigid section 102 at location 107. Inner surface 108
`of compliant member 104 preferably is substantially flush
`with inner Surface 109 of inner layer 112 when compliant
`member 104 is in an open position, as shown in FIG. 7A.
`0053) The distal end of catheter 100 is advanced over a
`dilator (not shown), which reduces the likelihood of kinking
`in the vicinity of distal section 101 during insertion of the
`device. Once the distal end of catheter 100 is positioned at
`the desired location, the dilator is removed from within
`working lumen 103 and aspiration may be provided through
`the working lumen. AS described hereinabove, when the rate
`of aspiration exceeds a predetermined threshold, the rigidity
`of compliant member 104 is overcome and causes compliant
`member 104 to be drawn inward towards working lumen
`103, as shown in FIG. 7B. Fluid flow through working
`lumen 103 is at least partially occluded to mitigate the rate
`of aspiration imposed upon a patient's vessel. When the rate
`of aspiration falls below the threshold to an acceptable rate,
`compliant member 104 returns to the open position shown in
`FIG. 7A to restore flow through working lumen 103.
`0054) Referring now to FIG. 8, an alternative embodi
`ment of the present invention is described. Catheter 130
`having proximal and distal ends and lumen 133 extending
`therebetween may be coupled to proximal assembly 24 of
`FIG. 1, which may include an inflation port, hemostatic port
`and blood outlet port, as described hereinabove. Unlike
`previous inventive embodiments, catheter 130 is constructed
`of a uniform material along its longitudinal length, as
`described with respect to the embodiment of FIGS. 1-2.
`Specifically, catheter 130 comprises polymer cover 140,
`wire braid 141, and inner layer 142 along its entire length,
`each of which may be constructed using materials described
`hereinabove.
`0055 Catheter 130 additionally comprises compliant
`member 145, which includes a compliant sheath disposed
`within working lumen 133 and affixed to inner Surface 148
`
`Page 11
`
`
`
`US 2004/0054348A1
`
`Mar. 18, 2004
`
`of inner layer 142 at proximal and distal points 146 and 147,
`respectively. A central region of compliant sheath 145 is not
`affixed to inner layer 142. When an acceptable rate of
`aspiration is provided through working lumen 133, compli
`ant sheath 145 is substantially rigid to hold compliant sheath
`145 in an open position, as shown in FIG. 8A. In the open
`position, compliant sheath 145 does not Substantially
`impede fluid flow through working lumen 133.
`0056. When a predetermined level of aspiration is
`exceeded, the rigidity of compliant sheath 145 is overcome,
`thereby causing sheath 145 to be drawn inward towards
`working lumen 133, as shown in FIG. 8B. Fluid flow
`through working lumen 133 is at least partially occluded to
`mitigate the rate of aspiration imposed upon a patient's
`vessel. When the rate of aspiration falls below the threshold
`to an acceptable rate, compliant sheath 145 returns to the
`open position shown in FIG. 8A to restore flow through
`working lumen 133.
`0057 Advantageously, the embodiment described in
`FIG. 8 comprises a uniform catheter body along its length
`and reduces the likelihood of kinking. It will be apparent to
`those skilled in the art that, like compliant member 74 of
`FIGS. 3-5, compliant sheath 145 of FIG.8 may be tailored
`to deploy for a predetermined rate of aspiration, e.g., by
`varying the material properties or by varying the distance
`between proximal and distal points 146 and 147.
`0.058 While preferred illustrative embodiments of the
`invention are described above, it will be apparent to one
`skilled in the art that various changes and modifications may
`be made therein without departing from the invention. The
`appended claims are intended to cover all Such changes and
`modifications that fall within the true spirit and scope of the
`invention.
`
`1. Apparatus Suitable for regulating the rate of aspiration
`provided through a working lumen of a catheter, the appa
`ratus comprising:
`a catheter having proximal and distal ends and a working
`lumen extending therebetween; and
`a compliant member coupled to the catheter in commu
`nication with the working lumen, the compliant mem
`ber configured to transition from an open position when
`a level of aspiration through the working lumen is
`below a threshold value, and a closed position wherein
`the compliant member at least partially occludes flow
`through the working lumen when the level of aspiration
`exceeds the threshold value.
`2. The apparatus of claim 1 wherein the compliant mem
`ber is disposed within a compliant Section, the compliant
`Section comprising the compliant member and a polymer
`COVC.
`3. The apparatus of claim 2 wherein the catheter further
`comprises at least one relatively rigid Section disposed
`adjacent the compliant Section.
`4. The apparatus of claim 3 wherein the relatively rigid
`Section comprises an inner layer, a wire braid, and the
`polymer cover.
`5. The apparatus of claim 4 wherein an inner Surface of
`the compliant member is substantially flush with an inner
`Surface of the inner layer.
`6. The apparatus of claim 2 wherein the compliant mem
`ber is disposed within a proximal region of the catheter.
`7. The apparatus of claim 2 wherein the compliant mem
`ber is disposed at the distal end of the catheter.
`
`8. The apparatus of claim 2 further comprising an inflation
`lumen disposed within the polymer cover, wherein the
`inflation lumen is coupled between an occlusive element
`disposed at the distal end of the catheter and an inflation port
`in communication with the proximal end of the catheter.
`9. The apparatus of claim