46 of the rotor 44. A radial seal 64 is provided in between the wall of the pump body 34 and a
`
`distal stepped region 66 on the rotor shaft 46, the function of which will be described below.
`
`(00{)4][0099]
`
`The impeller 48 includes a hub 56 and a plurality of blades 58 extending
`
`therefrom. The hub 56 is generally conical and, according to the first broad aspect of the
`
`present invention, is hollow throughout to form part of the central lumen of the guide
`
`mechanism 16. In this regard, the hub 56 is preferably provided with a gasket or seal member
`
`68 at its distal tip. The seal member 68 may be made of any suitable sealing material
`
`(including but not limited to silicone) such that the pump 12 and cannula 14 may be easily
`
`progressed along the guide wire 22 for delivery to a desired circulatory site. The seal member
`
`68 should also be robust enough to prevent the ingress of blood into the interior of the rotor
`
`hub 56 during pump operation, whether the guide wire 22 remains in place or is fully
`
`withdrawn. The blades 58 are dimensioned to reside in close tolerance with the interior surface
`
`of the shroud 36. In operation, the blades 58 impart both an axial and radial vector on the
`
`blood which causes it to flow outward through the flow ports 38 formed in the shroud 36. As
`
`used herein, the term "axial flow" is deemed to include flow characteristics like that shown in
`
`FIG. 3, which include both an axial and slight radial component. It is to be readily appreciated
`
`that, although shown as an axial flow type, blood pump 12 may comprise any number of
`
`suitable types of intravascular blood pumps, including but not limited to so-called "mixed
`
`flow" intravascular blood pumps without departing from the scope of the present invention.
`
`(00{)6][00100] The cannula 14 is coupled at its proximal end to the rotor shroud 36. This
`
`may be accomplished in any number of fashions, including but not limited to the use of
`
`adhesives. This may also be facilitated by dimensioning the shroud 36 to include a narrow
`
`inlet region 70 capable of being received flushly within the proximal end of the cannula 14.
`
`The inlet region 70 of the shroud 36 should preferably have a tapered interior surface for
`
`establishing a smooth flow transition between the cannula 14 and the region containing the
`
`impeller blades 58. Although shown as a single integral element, it is to be understood that the
`
`pump body 34 and shroud 36 may comprise two separate (and sometimes separable)
`
`components, the significance of which will become apparent below. The pump body 34 and
`
`shroud 36 may be constructed from any number of suitable materials, including but not limited
`.(19}
`
`

`

`to stainless steel or other medical grade compositions or alloys. The cannula 14 may also be
`
`constructed from any number of suitable materials, including but not limited to medical grade
`
`plastics. As shown, the cannula 14 may also be fortified with spiral-wound reinforcement wire
`
`72 within the walls of the cannula 14.
`
`[0066][00101] The drive cable assembly 18 includes the drive cable 62 and the drive cable
`
`sheath 32. The drive cable 62 is coupled to the rotor 44 via the cable adapter 60. The drive
`
`cable sheath 32 includes a central lumen 74 and a plurality of side lumens 76. The central
`
`lumen 74 serves as a protective covering for the drive cable 62. The central lumen 74, along
`
`with the side lumens 76, also forms part of the purge fluid delivery system 26 shown above in
`
`FIG. 2, which will be described in greater detail below. The side lumens 76 are provided in
`
`fluid communication with the fluid inlet conduit 28, while the central lumen 74 is provided in
`
`fluid communication with the fluid outlet conduit 30. The side lumens 76 are thus configured
`
`to deliver purge, fluid into the pump 12, while the central lumen 74 is configured to transport
`
`purge fluid away from the pump 12 along the length of the drive cable 62.
`
`[0067][00102] The pressurized purge fluid within the side lumens 76 may take one of two
`
`flow paths upon entry into the pump 12. One flow path passes through the interior of the pump
`
`12 and onward past the radial seal 64 to prevent the ingress of blood into the pump body 34
`
`during pump operation. More specifically, the purge fluid flows distally around the cable
`
`adapter 60, through the ball bearing assemblies 50, 52, and onward past the radial seal 64. This
`
`egress of purge fluid past the radial seal64 can be controlled to effectively thwart the ingress
`
`of blood past the radial seal 64, which might otherwise cause clotting and/or pump damage.
`
`The other flow path is directed back out the central lumen 74 for delivery to the fluid outlet
`
`conduit 30. In so doing, this flow path bathes the components of the pump 12 and/or drive
`
`cable 62 and thereby reduces frictional heating within the pump 12 and/or the central lumen
`
`74 of the sheath 32 during pump operation.
`
`[0068][00103] The "over-the-wire" guide mechanism 16 includes a central lumen through
`
`which the guide wire 22 may extend for the purpose of slideably advancing the blood pump 12
`
`and cannula 14 into a desired position within the circulatory system of a patient. In the
`.(201
`
`

`

`embodiment shown, this central lumen is established by forming and co-aligning the
`
`individual central lumens within each of the drive cable 62, the cable adapter 60, the shaft 46
`
`and hub 56 of the rotor 44, and the cannula 14. In this regard, the drive cable 62 is preferably
`
`of wound-wire construction having a central lumen formed therein. The central lumens within
`
`the cable adapter 60, rotor 44, and gasket 68 may be formed via machining or molding
`
`processes. These central lumens should preferably be sized such that they permit the slideable
`
`passage of the pump 12 and cannula 14 therealong, but do not interfere with or constrain the
`
`guide wire 22 to cause inadvertent rotation of the guide wire 22 during pump operation. As
`
`noted above, it is also contemplated to remove the guide wire 22 after the pump 12 and
`
`cannula 14 are properly positioned in the patient. In this case, the gasket or seal68 on the hub
`
`56 should be robust enough to reseal after the guide wire 22 is withdrawn and prevent the
`
`ingress of blood into the interior of the rotor 44.
`
`(0069][00104] Referring to FIG. 5, the motor coupler 24 includes a housing 78, a drive
`
`shaft adapter 80, and a bearing assembly 82. The drive shaft adapter 80 includes a drive shaft
`
`coupler 84 dimensioned to receive a drive shaft of a motor (not shown), and a drive cable
`
`coupler 86 dimensioned to receive the drive cable 62. Any of a variety of attachment
`
`techniques may be employed to securely fasten the drive cable 62 to the drive cable coupler
`
`86, including but not limited to adhesives, crimping, and laser welding. The drive shaft adapter
`
`80 is rotatably disposed within the housing 78 by the bearing assembly 82. The bearing
`
`assembly 82 includes a sleeve 88 (which may alternatively be formed as an integral part of the
`
`housing 78) for retaining a pair of ball bearing assemblies 90, 92 and a spring 94 of the type
`
`described above. That is, each bearing assembly 90, 92 generally comprises an inner race
`
`which rotates along with the drive shaft adapter 80, an outer race which remains in a static and
`
`fixed position against the inner surface of the retaining sleeve 88, and a plurality of ball
`
`bearings disposed between the inner and outer races. The spring 94 is provided to bias each
`
`bearing assembly 90, 92 axially away from one another to reduce axial play during operation.
`
`(0070][00105] The purge fluid delivery system 26 includes a housing 96 having a central
`
`lumen 98, an inflow port 100, and an outflow port 102. The housing 96 is also dimensioned to
`
`matingly receive a portion of the motor coupler 24. In this regard, a seal element 104 is
`.(211
`
`

`

`provided sandwiched in between the housing 96 and housing 78 and including an aperture
`
`which extends about the drive shaft adapter 80 as it exits the housing 78 to prevent the ingress
`
`of purge fluid into the motor coupler 24. A fluid guide structure 106 is also provided within
`
`the central lumen 98 for the purpose of separating the inflow and outflow ports 100, 102. The
`
`fluid guide structure 106 includes a central lumen 108 through which the drive cable 62
`
`extends, and an elevated portion 110 that retains an 0-ring 112 against the inner surface of the
`
`central lumen 98 of the housing 96. The drive cable sheath 32 is secured to the housing 96
`
`such that the inflow port 100 is communicatively coupled to the side lumens 76, and the
`
`outflow port 102 is communicatively coupled to the central lumen 74. In this fashion,
`
`pressurized purge fluid may be introduced through the inflow port 100 via inflow conduit 28,
`
`and removed through the outflow port 102 via outflow conduit 30. By way of example, the
`
`inflow conduit 28 and outflow conduit 30 may be coupled to their respective ports 100, 102
`
`via barbed connectors 114. Similarly, the inflow and outflow conduits 28, 30 may be equipped
`
`with any number of suitable connectors (such as those illustrated by way of example in FIG.
`
`2) for establishing fluid communication with a source of pressurized fluid (not shown). The
`
`pressurized fluid source (not shown) may include, but is not necessarily limited to, the use of a
`
`syringe, an indeflator, a fluid delivery pump, or an accumulator arrangement to provide the
`
`requisite delivery of pressurized fluid. The purge fluid delivery system 26 thus provides a two(cid:173)
`
`way transmission of purge fluid within the drive cable sheath 32 for the purposes of cooling
`
`the blood pump 12 and preventing the ingress of blood past the radial seal 64 and into blood
`
`pump 12.
`
`[0071][00106] Referring to FIG. 6, shown is a guidable intra-vascular blood pump system
`
`120 according to a second broad aspect of the present invention. As will be described
`
`hereinafter, the intravascular blood pump system 120 differs from the intravascular blood
`
`pump system 10 described above only as to the type of guide mechanism employed. In the
`
`interest of clarity and consistency, then, like reference numerals will be used to denote like
`
`elements and distinctions pointed out where necessary. Moreover, due to the commonality of
`
`principles employed in both intravascular blood pump systems 10, 120, a discussion to the
`
`level of detail set forth above is not deemed necessary with regard to the intravascular blood
`
`.(221
`
`

`

`pump system 120. Instead, those aspects in common with the intravascular blood pump 10 are
`
`hereby incorporated into the discussion of the intravascular blood pump system 120.
`
`(0072][00107]
`
`In its most general form, the intravascular blood pump system 120 of this
`
`second broad aspect of the present invention comprises the blood pump 12 and cannula 14
`
`arrangement, wherein the cannula 14 is equipped with a "side-rigger" or "rapid exchange"
`
`guide mechanism 122. In an important aspect of the present invention, the "rapid exchange" or
`
`"side-rigger" guide mechanism 122 includes a guide carriage 124 formed along at least a
`
`portion of the cannula 14, and a suitable guide element (such as guide wire 22) dimensioned to
`
`pass slidably through a lumen (not shown) extending through the guide carriage 124. The
`
`"rapid exchange" guide mechanism 122 thereby provides the ability to selectively guide the
`
`blood pump 12 and cannula 14 to a predetermined position in the circulatory system of a
`
`patient in the manner described above. Namely, the guide wire 22 may be first introduced into
`
`the vascular system of a patient through any suitable access point and guided to a desired
`
`location within the circulatory system of the patient, i.e. the left ventricle as shown. The blood
`
`pump 12 and cannula 14 may thereafter be advanced along the guide wire 22 and positioned in
`
`the trans-valvular configuration shown for providing left-heart assist.
`
`(0073][00108]
`
`FIGS. 7-9 further illustrate the "side-rigger" or "rapid-exchange" guide
`
`mechanism 122 of this second broad aspect of the present invention. In a preferred
`
`embodiment, the "side-rigger" guide mechanism 122 includes a lumen 126 formed within the
`
`guide carriage 124. The guide carriage 124 is preferably formed as an integral extension of the
`
`wall of the cannula 14. FIGS. 7 and 8 comport with the embodiment shown in FIG. 6, namely
`
`illustrating the guide carriage 124 formed along the exterior surface of the cannula 14. FIG. 9
`
`illustrates an alternate embodiment wherein the guide carriage 124 may be formed along the
`
`interior surface of the cannula 14. In either case, the guide wire 22 is advanced to a desired
`
`location in the vasculature of the patient, after which point the blood pump 12 and cannula 14
`
`can be slidably advanced therealong for delivery to the desired location according to the
`
`present invention. The guide wire 22 may thereafter be withdrawn from the patient. If the
`
`guide carriage 124 is formed along the exterior surface of the cannula 14 (as shown in FIGS.
`
`7-8), then the cannula 14 should preferably be positioned so that the guide carriage 124 does
`.(231
`
`

`

`not extend in a trans-valvular fashion. For example, with reference to FIG. 6, the guide
`
`carriage 124 should be positioned wholly within the left ventricle such that the pulsatile blood
`
`flow during beating heart procedures will not inadvertently pass through the side lumen 126
`
`and pass through the aortic valve.
`
`[0074][00109] The intravascular blood pump system 120 is constructed in virtually the
`
`same manner as the intravascular blood pump system 10 shown and described above, with the
`
`exception of the location of the respective guide mechanisms 16, 122. More specifically,
`
`because the guide mechanism 122 is disposed along the side of the cannula 14, there is no
`
`need to form a central lumen extending through the blood pump 12, drive cable assembly 18,
`
`purge fluid delivery system 26, and motor coupler 24 as detailed above with regard to the
`
`intravascular blood pump system 10. As such, these components need not be specially
`
`machined or molded to include such central lumens as was required with the intravascular
`
`blood pump system 10 set forth above.
`
`[0075][00110] Referring to FIG. 10, shown is a guidable intravascular blood pump system
`
`130 according to a third broad aspect of the present invention. Again, due to the commonality
`
`between many of the same components and features of the intravascular blood pump systems
`
`described above and the intravascular blood pump system 130, like reference numerals will be
`
`used to denote like elements and distinctions pointed out where necessary. As will be
`
`explained in greater detail below, the intravascular blood pump system 130 employs yet
`
`another unique and useful guide mechanism according to the present invention. However,
`
`because many of the same components are employed, a discussion to the level of detail set
`
`forth above is not deemed necessary with regard to the intravascular blood pump system 130.
`
`Instead, those aspects in common with the intravascular blood pumps described above are
`
`hereby incorporated into the discussion of the intravascular blood pump system 130.
`
`[0076][00111]
`
`In its most general form, the intravascular blood pump system 130 of this
`
`third broad aspect of the present invention comprises the blood pump 12 and cannula 14
`
`arrangement, wherein a "guide catheter" 132 is provided as the guide mechanism for
`
`positioning the pump 12 and cannula 14 at a desired location within the circulatory system of
`.(241
`
`

`

`the patient. More specifically, with brief reference to FIG. 12, the intravascular blood pump
`
`system 130 is formed in two separate assemblies according to the present invention: a conduit
`
`assembly 134 and pump assembly 136. In its most basic form, the conduit assembly 134
`
`comprises the guide catheter 132 and cannula 14 coupled to the rotor shroud 36. The pump
`
`assembly 136 is constructed such that the pump body 34 and rotor 44 can be disengaged from
`
`the rotor shroud 36 and removed entirely from the conduit assembly 134. Referring again to
`
`FIG. 10, this dual construction forms a significant feature of the present invention because it
`
`provides the ability to form the blood pump 12 at a desired location in a patient using two
`
`separate and distinct steps. The first step involves positioning the conduit assembly 134 (with
`
`the pump assembly 136 removed) within a patient such that the shroud 36 and cannula 14 are
`
`each disposed in a desired location, such as a trans-valvular configuration for cardiac assist
`
`procedures. In an important aspect, the task of positioning the conduit assembly 134 within the
`
`patient may be advantageously facilitated through the use of any number of well known
`
`guidance mechanisms, including but not limited to guide wires, balloon catheters, imaging
`
`wires, guide catheters, and/or techniques involving ultra-sound or flouroscopy. The second
`
`step in providing the intravascular blood pump system 130 of the present invention involves
`
`advancing the pump assembly 136 through the conduit assembly 134 such that the rotor 44
`
`docks within the shroud 36 to form the pump 12 at the desired location.
`
`[0077][00112] By way of clarification, the term "cannula" is used to denote cannula 14
`
`because it serves a primary purpose of transporting fluid into the blood pump 12, whereas the
`
`term "catheter" is used to denote the catheter 132 because it serves a primary purpose of
`
`guiding or directing devices or components (i.e. the pump assembly 136) to a desired location
`
`within the body. It is to be readily understood, however, that these terms are only used for
`
`convenience and in a general fashion such that the cannula 14 may serve certain guiding
`
`functions and the catheter 132 may serve certain fluid transportation functions without
`
`departing from the scope of the present invention. For example, the cannula 14 may be
`
`equipped with dedicated lumens to receive various guide mechanisms (such as guide wires,
`
`balloon catheters, selectively deformable elements such as Nitonol, etc). In similar fashion, the
`
`guide catheter 132 may be used to transport fluid to and/or from the patient, such as by
`
`providing apertures 138 along predetermined regions of the catheter 132 .
`.(251
`
`

`

`[0078][00113]
`
`FIG. 11 demonstrates a significant feature of the present invention involving
`
`the use of the guide catheter 132 to transport fluid to and/or from the patient. An optional
`
`perfusion assembly 140 is provided as part of the intravascular blood pump system 130 of the
`
`present invention. The perfusion assembly 140 includes a conduit 142 in fluid communication
`
`with the apertures 138, which in this case are formed near the distal region of the guide
`
`catheter 132 a short distance downstream from the blood pump 12. In use, blood will pass
`
`along the exterior of the guide catheter 132 for distribution throughout the body, as well as
`
`within the interior of the guide catheter 132 after passing into the apertures 138. The perfusion
`
`assembly 140 may then be employed to selectively reroute blood from within the guide
`
`catheter 132 to a point within the patient's vasculature downstream from the point where the
`
`guide catheter 132 enters the body. A hemostasis valve assembly 146 of the perfusion
`
`assembly 140 permits the drive cable assembly 18 to pass through to the purge fluid delivery
`
`system 26 while preventing blood flow other than into the perfusion assembly 140. A seal
`
`assembly 150 of the purge fluid delivery system 26 permits the drive cable 62 to pass through
`
`to the motor 20 while preventing the flow of purge fluid other than into and from the purge
`
`fluid delivery system 26. The perfusion assembly 140 includes a control mechanism 148 for
`
`selectively controlling the distribution of perfusion blood flow from the perfusion assembly
`
`140 into the patient. This control mechanism 148 may be automatic based on certain feedback
`
`criteria or manually operated.
`
`[0079][00114]
`
`FIGS. 12-17 illustrate an exemplary construction of the intravascular blood
`
`pump system 130 according to the third broad aspect of the present invention. As shown in
`
`FIG. 12, the conduit assembly 134 may be selectively disengaged so as to remove the pump
`
`assembly 136 therefrom. According to the present invention, the conduit assembly 134 may be
`
`introduced (without the pump assembly 136) into the circulatory system of a patient and
`
`selectively guided such that the rotor shroud 36 and cannula 14 are positioned at a desired
`
`location. The pump assembly 136 can thereafter be selectively introduced into the conduit
`
`assembly 134. A challenge in such a "back-loading" arrangement is ensuring that the pump
`
`assembly 136 docks appropriately within the rotor shroud 36 and is maintained in proper
`
`engagement during operation of the resulting pump 12 .
`.(261
`
`

`

`[0080][00115] An exemplary docking arrangement will now be described with reference to
`
`FIG. 14. In a preferred embodiment, the rotor 44 may be properly and accurately docked
`
`within the shroud 36 by forming angled mating surfaces on corresponding portions of the
`
`shroud 36 and pump body 34. More specifically, an angled mating surface may be formed on
`
`the interior surface of the rotor shroud 36 along that portion extending proximally from the
`
`flow aperture 38. A corresponding angled mating surface may be provided along the exterior
`
`surface of the pump body 34 along a distal portion thereof. The mating surfaces shown in FIG.
`
`14 may preferably be formed in the range from about 2 degrees to 10 degrees, and more
`
`preferably formed in the range from about 3 degrees to 6 degrees. Mating angles within these
`
`ranges are adequate to guide the distal end of the pump body 34 to a point generally flush with
`
`the proximal edge of the flow aperture 38 as shown in FIG. 14. In this fashion, the pump
`
`assembly 136 and the rotor shroud 36 combine to form the blood pump 12. More importantly,
`
`this docking is carried out such that the rotor 44 and rotor blades 58 are maintained in proper
`
`position for efficient and safe pump operation.
`
`[0081][00116] An exemplary biasing scheme for maintaining the pump assembly 136 in
`
`this docked relationship will now be described with reference to FIGS. 12-13 and 16-17. The
`
`conduit assembly 134 is preferably equipped with a male quick-connect coupling 152 capable
`
`of engaging with a female quick-connect coupling 154 forming part of the perfusion assembly
`
`140 of the present invention. A bias spring 156 is provided in between the perfusion assembly
`
`140 and the housing 96 of the purge fluid delivery system 26. The bias spring 156 is
`
`preferably dimensioned so as to be in tension when the male quick-connect 152 is engaged
`
`within the female quick-connect 154 as part of the docking process of the present invention.
`
`As such, the bias spring 156 serves to maintain the pump assembly 136 in the docked position
`
`within the rotor shroud 36. The bias spring 156 may be coupled to the housing 96 of the purge
`
`fluid delivery system 26 in any number of suitable fashions. One such coupling arrangement
`
`may comprise a female quick-connect coupling 158 attached to the housing 96 and a male
`
`quick-connect coupling 160 attached to the bias spring 156 .
`
`.(271
`
`

`

`(0082][00117] An exemplary embodiment of the perfusion assembly 140 is shown with
`
`reference to FIGS. 12-13 and 17. The perfusion assembly 140 shown includes the hemostasis
`
`valve 146 coupled to the female quick-connect coupling 154. A length of tubing 162 extends
`
`between the opposing barb connectors of the hemostasis valve 146 and the female quick(cid:173)
`
`connect coupling 154. A continuous lumen is formed extending through the interior of the
`
`male quick-connect coupling 152, the female-quick-connect coupling 154, the tubing 162, and
`
`the hemostasis valve 146. The drive cable assembly 18 extends through this continuous lumen
`
`and exits through a Touehy-Borst hemostasis seal 164 which prevents the migration of blood
`
`out of the proximal end of the perfusion assembly 140. A side-port 166 is disposed in fluid
`
`communication with the central lumen of the perfusion assembly 140. In one embodiment, this
`
`side-port 166 may be equipped with a conduit 168 having a stop-cock 170 to selectively
`
`control the distribution of blood through a perfusion conduit (i.e. conduit 142 of FIG. 11)
`
`coupled to the stop-cock 170. It will be appreciated that this type of manual control system for
`
`selectively perfusing the patient may be replaced with control circuitry for automatically
`
`controlling the rate of perfusion. Such automatic perfusion may be based on control algorithms
`
`based on contemporaneous feedback or pre-programmed thresholds.
`
`(0083][00118] The foregoing discussion details a host of inventive aspects forming part of
`
`the present invention. It will be appreciated by those skilled in the art that changes could be
`
`made to the embodiments described above without departing from the broad inventive
`
`concepts thereof. The following evidences, by way of example only, various additional aspects
`
`forming part of the present invention.
`
`(0084][00119]
`
`FIG. 18 illustrates an alternate configuration of the intravascular blood pump
`
`system 130 of the third broad aspect of the present invention having an alternate bearing
`
`assembly, purge fluid delivery, and docking scheme. The bearing assembly includes a seal
`
`spring 182 and a bearing assembly 180. The bearing assembly 180 includes an inner race 184,
`
`an outer race 186, and a plurality of balls 188 which enable the inner race 184 to rotate along
`
`with the rotor shaft 46 while the outer race 186 remains in a static and fixed position relative
`
`to an inner surface of the pump body 34. An 0-ring 190 is disposed within a groove formed in
`
`the rotor shaft 46 so as to maintain the bearing assembly 180 against the seal spring 182. The
`.(281
`
`

`

`0-ring 190 is further secured within the groove in the rotor shaft 46 via a contoured lip portion
`
`extending from the distal end of the cable adapter 60. The proximal end of the cable adapter
`
`60 flushly engages the drive cable 62.
`
`(0086][00120] The purge fluid delivery system of the embodiment shown in FIG. 18
`
`provides for a one way delivery of purge fluid to the blood pump 12. That is, pressurized fluid
`
`(namely, fluid pressurized to some level elevated above the blood pressure in the surrounding
`
`vessel) is injected in between the drive cable 62 and the interior of the protective sheath 32
`
`during operation. This serves to reduce any frictional heating that exists between the drive
`
`cable 62 and sheath 32. The pressurized fluid also flows through the interior of the pump 12
`
`such that, if the seal at 192 is broken, the pressurized fluid will flow past the open seal 192 and
`
`onward through the blood flow ports 38 formed in the shroud 36. This serves to keep blood
`
`from entering the pump 12 in an effort to avoid clotting and/or damaging the pump 12.
`
`(0086][00121] The pump assembly 136 may be docked within the conduit assembly 134 in
`
`any number of different fashions without departing from the scope of the present invention.
`
`That is to say, the docking scheme shown in FIG. 18 is set forth by way of example only and
`
`is not to be deemed limiting or restrictive as to numerous ways to temporarily engage or
`
`"dock" the pump assembly 136 within the conduit assembly 134. The only requirement is that
`
`the pump assembly 136 and conduit assembly 134 dock such that the rotor 44 is disposed
`
`within the shroud 36 to provide the desired axial flow through the cannula 14 and out the
`
`shroud 36. The exemplary docking scheme involves forming an annular engagement groove
`
`194 along the interior of the shroud 36, and forming a complementary annular ridge 196 along
`
`the exterior surface of the pump body 34. During insertion, the pump assembly 136 will be
`
`advanced into the conduit assembly 134 until the annular ridge 196 on the pump body 34
`
`engages within the groove 194 formed in the shroud 36. This docking scheme is generally
`
`advantageous in that the engagement action between the annular ridge 196 and groove 194
`
`will provide tactile feedback to the physician during the process of inserting the pump
`
`assembly 136 into the conduit assembly 134 such that the physician will be able to determine
`
`when the docking has been completed.
`
`.(291
`
`

`

`(0087][00122] As will be appreciated by those skilled in the art, the location of the annular
`
`ridge 196 and engagement groove 194 may be varied such that they are disposed closer or
`
`farther away from the flow apertures 38. It may be advantageous to form these docking
`
`structures close to the flow apertures 38 in an effort to thwart the ingress of blood into the
`
`junction extending between the interior of the shroud 36 and the exterior surface of the pump
`
`body 34. It is also contemplated to employ selectively inflatable structures, such as balloons,
`
`in an effort to temporarily engage or dock the pump assembly 136 within the conduit assembly
`
`134. In this regard, one or more lumens may be formed within the pump body 34 extending
`
`from the interior of the pump body 34 in fluid communication with a balloon disposed along
`
`the exterior surface of the pump body 34. The pressurized fluid flowing within the interior of
`
`the pump body 34 may then be used to inflate the balloon, which will then engage within an
`
`annular groove in the shroud 36, such as at 194. Of course, the engagement structures may
`
`also be reversed without departing from the scope of the present invention. For example, the
`
`shroud 36 may be equipped with a fluid delivery lumen therein for inflating a balloon disposed
`
`on the interior surface of the shroud 36, which may in tum be disposed within an annular
`
`engagement groove formed along the exterior surface of the pump body 34.
`
`(0088][00123] While this invention has been shown in use largely in during left-heart
`
`applications it is to be readily appreciated that this does not limit the applications of this
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`invention for use in left heart support only. Rather, the guidable intravascular blood pump of
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`the present invention can be utilized in right-heart support applications and a wide variety of
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`other applications apparent to those skilled in the art. For example, with reference to FIG. 19,
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`shown is an intravascular blood pump 200 (of the type shown and described above with
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`reference to FIGS. 2-5) configured for use in a right-heart support application. In this
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`embodiment, the intravascular blood pump system 200 is equipped, by way of example, with
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`an "over-the-wire" guide mechanism 16 comprising a balloon catheter 202. It is to be readily
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`appreciated that, although shown and described below in terms of an embodiment of the type
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`shown in FIGS. 2-5, the intravascular blood pump systems 120, 130 disclosed herein may also
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`be configured for use in right-heart applications. Such right-heart configurations, and others
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`apparent to those skilled in the art based on the broad principles enumerated in this
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`application, are contemplated as being within the scope of the present invention .
`.(301
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`[0089][00124] The intravascular blood pump system 200 is shown positioned within the
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`heart, such as may be advantageous to provide right heart support during beating heart
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`surgery. To position the guidable intravascular blood pump system 200 in the right heart
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`according to the present invention, a suitable guide element (such as balloon catheter 202) is
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`first advanced to a desired location within the heart via the "sail" action of an inflated balloon.
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`After the balloon catheter 202 is located in the desired position (such as in the pulmonary
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`artery as shown), the intravascular blood pump system 200 according to the present invention
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`may be advanced over the balloon catheter 202 and guided into a desired arrangement. For
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`right heart support, this would involve advanced into the pump 12 and cannula 14 overt the
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`balloon catheter 202 until the fluid inlet 204 is disposed within the vena cava (or right atrium)
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`and the fluid outlet 206 is positioned within the pulmonary artery. The pump 12 may then be
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`selectively (i.e. automatically or on-demand) controlled to transport blood from the vena cava
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`(or right atrium) in a trans-valvular fashion through the tricuspid valve, the right ventricle, and
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`the pulmonary valve for deposit w