Implantable blood pump assembly including an anti-rotation mechanism for an outflow cannula and method of assembling the same

Abstract

The present invention discloses an implantable blood pump assembly, comprising: a housing defining an inlet, an outlet and a flow path extending from the inlet to the outlet; a rotor positioned within the scope of the flow path; a stator positioned within the housing and operable to drive the rotor, and an outflow cannula, the outflow cannula including a joint assembly configured to removably mechanically connect to the outlet joint and including a first member of an anti-rotation mechanism and a first member of an axial lock; the housing includes an outlet joint, the outlet joint including a second member of the anti-rotation mechanism and a second member of the axial lock. During insertion of the outflow cannula into the housing outlet, the first member and the second member of the anti-rotation mechanism are positioned to engage with each other prior to the first member and the second member of the axial lock.

Description

[0001] Cross - Reference to Related Applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 62 / 904,950, filed Sep. 24, 2019, the disclosure of which is hereby incorporated by reference in its entirety. TECHNICAL FIELD

[0003] The present invention generally relates to mechanical circulatory support systems and, more particularly, to a coupling mechanism for connecting an outflow cannula to an implantable blood pump assembly. BACKGROUND OF THE INVENTION

[0004] A ventricular assist device, known as a VAD, is an implantable blood pump that can be used both short term (e.g., for days, months) and long term (e.g., for years or the entire life cycle) in situations where a patient's heart is unable to provide adequate blood circulation, often referred to as arrhythmia or heart failure. A patient with arrhythmia can use a ventricular assist device while waiting for a heart transplant or during long-term targeted treatment. In another example, a patient can use a ventricular assist device during recovery from heart surgery. Thus, a ventricular assist device can assist a failing heart (e.g., provide partial support) or can effectively replace the function of a congenital heart, and the ventricular assist device can be implanted in a patient and powered by an in-patient or out-of-patient power source.

[0005] In conventional ventricular assist devices, an outflow cannula is connected to a pump housing to direct blood from the pump to the patient's ascending or descending aorta. In some at least known ventricular assist devices, the outflow cannula is connected to the pump housing during implantation. Additionally, at least some known ventricular assist devices allow the outflow cannula to rotate relative to the pump housing after installation (i.e., after surgery). Further, some known ventricular assist devices do not limit the number of revolutions of the outflow cannula relative to the pump housing during installation. Thus, known ventricular assist devices can allow the outflow cannula to undergo excessive rotation and / or torsion during implantation and / or postoperatively.

[0006] Accordingly, there is a need for an improved coupling mechanism for connecting an outflow cannula to an implantable blood pump. SUMMARY OF THE INVENTION

[0007] The present invention is directed to an implantable blood pump assembly, comprising: a housing that defines an inlet, an outlet, and a flow path extending from the inlet to the outlet, the housing including an outlet fitting; a rotor positioned within the flow path and operable to pump blood from the inlet to the outlet; a stator positioned within the housing and operable to drive the rotor; and an outflow cannula that includes a fitting assembly configured for removably mechanically coupling to the outlet fitting and includes a first member of an anti-rotation mechanism and a first member of an axial lock; the housing includes an outlet fitting that includes a second member of the anti-rotation mechanism and a second member of the axial lock. During insertion of the outflow cannula into the housing outlet, the first members of the anti-rotation mechanism and the second members are positioned to engage each other prior to the first members and the second members of the axial lock.

[0008] The present invention is also directed to an implantable blood pump assembly, comprising: a housing, wherein the housing defines an inlet, an outlet, and a flow path extending from the inlet to the outlet, the housing including an outlet fitting; a rotor positioned within the flow path and operable to pump blood from the inlet to the outlet; a stator positioned within the housing and operable to drive the rotor; and an outflow cannula that includes a fitting assembly for removably mechanically coupling to the outlet fitting and includes an adapter sleeve and a threaded ring rotatably coupled to the adapter sleeve. The adapter sleeve includes one of: (i) a plurality of longitudinally extending grooves or (ii) a plurality of longitudinally extending splines. The threaded ring includes a first thread. The housing includes an outlet fitting, wherein the outlet fitting includes one of: (i) a plurality of longitudinally extending grooves or (ii) a plurality of longitudinally extending splines, and a second thread is configured to threadedly engage the first thread. The plurality of splines are configured for mating engagement with the plurality of grooves to prevent relative movement between the outflow cannula and the pump housing. During insertion of the outflow cannula into the housing outlet, the plurality of grooves and the plurality of splines are positioned to engage each other prior to the first thread and the second thread.

[0009] The present invention further relates to a method for an implantable blood pump assembly, the method comprising: providing an outflow cannula comprising a connector assembly, the connector assembly including a first member of an anti-rotation mechanism and a first member of an axial lock. The method further comprises: providing a blood pump comprising a housing, the housing defining an inlet, an outlet, and a flow path extending from the inlet to the outlet, wherein the housing includes an outlet connector, the outlet connector including a second member of the anti-rotation mechanism and a second member of the axial lock. The method further comprises: aligning the first member of the anti-rotation mechanism with the second member of the anti-rotation mechanism, and inserting the outflow cannula into the outlet of the housing such that the first and second members of the anti-rotation mechanism engage each other prior to the first and second members of the axial lock. The anti-rotation mechanism restricts rotation of the outflow cannula relative to the pump housing. The method further comprises: engaging the first member of the axial lock with the second member of the axial lock such that the axial lock prevents axial movement of the outflow cannula relative to the pump housing. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a schematic view of a mechanical blood circulation support system implanted in a patient.

[0011] Figure 2 is Figure 1 an exploded view of certain components of the blood circulation support system shown.

[0012] Figure 3 is a schematic view of a blood pump assembly of a mechanical blood circulation support system adapted for use in Figure 1 and shown in an operable position implanted in a patient.

[0013] Figure 4 is Figure 3 a schematic cross-sectional view of the blood pump assembly of

[0014] Figure 5 is a perspective view of a pump housing portion and an outflow cannula of a blood pump assembly adapted for use in Figure 3 and Figure 4 and shown.

[0015] Figure 6 is Figure 5 a cutaway perspective view of the outflow cannula of

[0016] Figure 7 is Figure 5 a perspective view of the pump housing portion shown in

[0017] Figure 8 is Figure 5 a perspective view of the connector assembly of the outflow cannula shown in

[0018] Figure 9Yes Figure 5 Cross-sectional view of the outflow cannula.

[0019] Figure 10 Yes Figure 5 Cutaway view of the outlet joint of the pump housing.

[0020] Figure 11 Yes Figure 10 Cross-sectional view of the outlet joint.

[0021] Figure 12 Yes Figure 5 End view of the outflow cannula.

[0022] Figure 13 Yes Figure 10 End view of the outlet joint.

[0023] Figure 14 Yes Figure 5 Cross-sectional view of the pump housing portion and the outflow cannula shown.

[0024] Figure 15 Is along Figure 14 Cut along the "15-15" cutting line in Figure 14 Cross-sectional view of the pump housing and the outflow cannula.

[0025] Figure 16 Is along Figure 5 Cut along the "16-16" cutting line in Figure 5 Cross-sectional view of the pump housing and the outflow cannula.

[0026] Figure 17 Yes Figure 16 Another cross-sectional view of the pump housing and the outflow cannula shown, showing the pump housing and the outflow cannula in an aligned state.

[0027] Figure 18 Is during the first step of installation,[[]] Figure 15 Another cross-sectional view of the pump housing and the outflow cannula shown.

[0028] Figure 19 Is during the second step of installation,[[]] Figure 18 Another cross-sectional view of the pump housing and the outflow cannula shown.

[0029] Figure 20 Is a flowchart showing an embodiment of a method of installing a blood pump assembly. Detailed Description

[0030] The present invention is directed to an implantable blood pump assembly, and more particularly, to a coupling mechanism for connecting an outflow cannula to an implantable blood pump assembly.

[0031] Referring to the accompanying drawings,[[]]Figure 1 FIG. Figure 1 is a schematic view of a mechanical blood circulation support system 10 implanted into a patient's body 12. The mechanical blood circulation support system 10 includes an implantable blood pump assembly 14, which includes a blood pump 16, a ventricular cuff 18, and an outflow cannula 20. The mechanical blood circulation support system 10 also includes an external system controller 22 and one or more power sources 24.

[0032] The blood pump assembly 14 can be implanted as or include a ventricular assist device that is attached to the highest point of the left ventricle shown in the figure, or the right ventricle, or both ventricles of the heart 26. Additionally referring Figure 2 to, the blood pump assembly 14 can be attached to the heart 26 as further described in this application by suturing to the heart 26 and coupling to the ventricular cuff 18 of the blood pump assembly 14. The other end of the blood pump assembly 14 is connected to the ascending aorta or the descending aorta through the outflow cannula 20 such that the blood pump assembly 14 effectively transfers and propels blood from the failing ventricle into the aorta for circulation to the rest of the patient's vascular system. The ventricular assist device can include a centrifugal pump (shown in the figure) or an axial flow pump further detailed in the present invention, which is capable of pumping the entire blood output delivered from the pulmonary circulation to the left ventricle (i.e., up to 10 liters per minute).

[0033] Figure 1 FIG. Figure 1 shows the mechanical blood circulation support system 10 during battery-powered operation. A communication line 28 connects the implanted blood pump assembly to the external system controller 22 for monitoring the operation of the system 10. In the illustrated embodiment, the communication line 28 is shown as a drive line exiting through the patient's abdomen 30, although it should be understood that the blood pump assembly 14 may be connected to the external system controller 22 through any suitable communication line, including wired and / or wireless communication. The system can also be powered by one, two, or more batteries 24. It is noted that although the system controller 22 and the power source 24 are shown outside the patient's body, the communication line 28, the system controller 22, and / or the power source 24 can still be partially or fully implantable into the patient's body as separate components or as an integrated part of the blood pump assembly 14.

[0034] Figure 3 FIG. Figure 3 is a schematic view of an implantable blood pump assembly 100 of the mechanical blood circulation support system 10 adapted to be used Figure 1 in, where the blood pump assembly 100 is shown in the operative position implanted into the patient's body. Figure 4 FIG. Figure 4 is Figure 3 a schematic cross-sectional view of the blood pump assembly 100. In the illustrated embodiment, the blood pump assembly 100 is a left ventricular assist blood pump assembly connected to the left ventricle LV of the heart H.

[0035] The blood pump assembly 100 includes a blood pump 102 with an annular housing 104 having a first outer surface or first outer wall 106 and a second outer surface or second outer wall 108. The blood pump assembly 100 also includes an inflow cannula 110 (generally, an inlet conduit) extending from the first outer wall 106 of the pump housing 104 in the illustrated embodiment. When the blood pump assembly 100 is implanted into a patient as Figure 3 shown, the first outer wall 106 of the housing 104 is positioned against the patient's heart, and the second outer wall 108 of the housing 104 faces away from the heart H. The inflow cannula 110 extends into the left ventricle LV of the heart H to connect the blood pump assembly 100 to the heart H. The second outer wall 108 of the housing 104 has a chamfered edge 109 to avoid irritating other tissues, such as the patient's diaphragm, that may come into contact with the blood pump assembly 100.

[0036] The blood pump assembly also includes a stator 112, a rotor 114, and an on-board controller 116, all enclosed within the pump housing 104. In the illustrated embodiment, the stator 112 and the on-board controller 116 are positioned on the inflow side of the pump housing 104 toward the first outer wall 106, and the rotor 114 is positioned along the second outer wall 108. In other embodiments, the stator 112, the rotor 114, and the on-board controller 116 can be positioned at any suitable location within the pump housing 104 that enables the blood pump assembly 100 to function as described in the present invention. Power is provided to the operable components (e.g., the stator 112 and the on-board controller 116) of the blood pump assembly from a remote power source via a power supply line 120.

[0037] Additionally referring Figure 4 to, the pump housing 104 defines an inlet 122 for receiving blood from a ventricle (e.g., the left ventricle LV), an outlet 124 for returning blood to the blood circulation system, and a flow path 126 extending from the inlet 122 to the outlet 124. The pump housing 104 also defines an inner chamber 128 separated from the flow path 126, for example, by one or more partition walls 130. The pump housing 104 also includes an intermediate wall 132 positioned between the first outer wall 106 and the second outer wall 108, and a peripheral wall 134 extending between the first outer wall 106 and the intermediate wall 132. The first outer wall 106, the partition walls 130, the intermediate wall 132, and the peripheral wall 134 together define the inner chamber 128, within which the stator 112 and the on-board controller are enclosed.

[0038] In the illustrated embodiment, the pump housing 104 also includes a cap portion 136 removably attached to the pump housing 104 along the intermediate wall 132. In the illustrated embodiment, the cap portion 136 is threadably attachable to the pump housing 104, although in other embodiments, any suitable attachment means capable of enabling the blood pump assembly 100 to function as described in the present invention may be utilized to attach the cap portion 136 to the pump housing 104. For example, in certain embodiments, the cap portion 136 is non-removably attached to the pump housing 104, such as by welding. The removable cap portion 135 includes a second outer wall 108, a chamfered edge 109, and defines an outlet 124. The cap portion 136 also defines a vortex chamber 138 in fluid communication with the outlet 124, and a rotor chamber 140 in which the rotor 114 is positioned. Any suitable attachment structure may be used to attach the cap portion 136 to the pump housing 104. For example, the cap portion 136 may be sealed to the peripheral wall 134 by engaging the peripheral wall 134 with a thread.

[0039] The rotor 114 is positioned within the blood flow path 126, specifically within the rotor chamber 140, and is operable to rotate in response to an electromagnetic field generated by the stator 112 to pump blood from the inlet 122 to the outlet 124. The rotor defines a central bore 142 through which blood flows during operation of the blood pump 102. The rotor 114 includes impeller vanes 144 located within the vortex chamber 138 of the blood flow path 126, and a shroud 146 that covers the end of the impeller vanes 144 facing the second outer wall 108 to assist in guiding the blood flow into the vortex chamber 138.

[0040] In the illustrated embodiment, the rotor 114 includes a permanent magnet 148 that defines the central bore 142. The permanent magnet 148 has a permanent magnetic north pole N and a permanent magnetic south pole S for combined active and passive magnetic levitation of the rotor 114 and for rotation of the rotor 114. In operation, the stator 112 is controlled to drive (i.e., rotate) the rotor and to radially levitate the rotor 114 by generating an electromagnetic field that interacts with the permanent magnetic poles S and N of the permanent magnet 148.

[0041] Any suitable stator 112 may be employed to rotate the rotor 114. The stator 112 generally includes a plurality of winding structures that generate a suitable electromagnetic field that interacts with the rotor 114 to cause the rotor 114 to rotate and levitate. In the illustrated embodiment, the stator 112 includes a plurality of pole pieces 150 circumferentially spaced about a partition wall 130. An exemplary blood pump assembly 100 includes six pole pieces 150, two of which are Figure 4is visible. In another embodiment, the blood pump assembly 100 may include more or fewer than six pole pieces, such as four pole pieces, eight pole pieces, or any other suitable number of pole pieces capable of enabling the blood pump assembly 100 to perform the functions described in the present invention. In the illustrated embodiment, each pole piece 150 includes a drive coil 152 for generating an electromagnetic field to rotate the rotor 114, and a suspension coil 154 for generating an electromagnetic field to control the radial position of the rotor 114.

[0042] For example, in U.S. Patent No. 9,849,224, suitable methods for controlling the stator 112 and generating an electromagnetic field to rotate and radially suspend the rotor 114 are described, and for all purposes, the entire content thereof is incorporated herein by reference. Although in the illustrated embodiment, the drive coil 152 and the suspension coil 154 are shown as separate coils, it should be understood that the drive coil 152 and the suspension coil 154 may be provided as a single coil configured to generate an electromagnetic field for both rotating and suspending the rotor 114.

[0043] The inflow cannula 110 is attached to the pump housing 104 at the inlet 122. The pump housing 104 includes suitable connection structures at the inlet 122 for connecting the inflow cannula 110 to the pump housing 104. In some embodiments, for example, the pump housing 104 includes a threaded sleeve with threads that are threadedly engaged with the threads on the downstream or proximal end of the inflow cannula 110 for connecting the insertion cannula 100 to the pump housing 104.

[0044] The on-board controller 116 is operably connected to the stator 112 and is configured to control the operation of the pump 102 by controlling the current supply to the stator, and thereby control the rotation of the rotor 114. In some embodiments, the on-board controller 116 is configured to perform closed-loop speed control of the pump rotor 114 based on feedback received from one or more sensors (e.g., pressure sensors, flow sensors, accelerometers, etc.). The on-board controller 116 may also be configured to control the rotor 114 with continuous flow operation and / or pulsatile flow operation.

[0045] The on-board controller 116 may include one or more modules or devices enclosed within the pump housing 104. The on-board controller 116 may generally include any suitable computer and / or other processing unit, including a computer, a processing unit, and / or a suitable combination of the like that can be communicatively coupled to each other (e.g., the on-board controller 116 may form all or part of a controller network). Accordingly, the on-board controller 116 may include one or more processors and associated storage devices configured to perform various computer-implemented functions (e.g., performing the methods, steps, calculations, and / or similar functions protected by the present invention). As used in the present invention, the term "processor" refers not only to the integrated circuit included in a computer as referred to in the art, but also to a controller, a microcontroller, a microcomputer, a programmable logic controller (PLC), an application-specific integrated circuit (ASIC), a digital signal processor (DSP), a field-programmable gate array (FPGA), and other programmable circuits. In addition, the memory device of the on-board controller 116 may generally include memory components, including but not limited to non-transitory computer-readable media (e.g., random access memory (RAM)), computer-readable non-volatile media (e.g., flash memory), floppy disks, compact disc read-only memory (CD-ROM), magneto-optical disc (MOD), digital versatile disc (DVD), and / or other suitable memory components. Such storage devices may generally be configured to store suitable computer-readable instructions such that when executed by the processor, the storage devices configure the on-board controller 116 to perform functions including but not limited to controlling the current supply to the stator 112, regulating the speed of the rotor 114, and various other computer-implemented functions suitable thereto.

[0046] In the illustrated embodiment, the on-board controller 116 is provided as one or more circuit boards 156 and various components carried on the circuit boards (e.g., processors and storage devices) to control the operation of the pump 102 by controlling the current supply to the stator 112.

[0047] A communication line (e.g., communication line 28) couples the blood pump assembly 100 and the on-board controller 116 to an external controller 22 that monitors the operation of the system via various software applications. The blood pump assembly 100 itself may also include several software applications that can perform various functions via the on-board controller 116, such as functions that control radial suspension and / or drive the rotor of the pump assembly 100 during operation. The external controller 22, in turn, may be coupled to a battery 24 or a power module (not shown) connected to an alternating current (AC) outlet. The external system controller 22 may also include an emergency backup battery (EBB) that powers the system (e.g., when the battery 24 is depleted), and a membrane overlay that includes Bluetooth functionality for wireless data communication. An external computer, which can be configured by an operator such as a clinician or a patient, may further couple the external computer to the blood circulation support system 10, for configuring the external system controller 22, the configured blood pump assembly 100, and / or specific parameters of the patient, for updating the software on the external system controller 22 and / or the configured blood pump assembly 100, monitoring the operation of the system, and / or serving as a line for system input or output.

[0048] Figure 5 is adapted for use in Figures 1 - 4 a portion of the outflow cannulas 200 and the pump housing 300 of the blood pump assemblies 14 and 100. Figure 6 is a cutaway view of the outflow cannula 200, and Figure 7 is Figure 5 a perspective view of the portion of the pump housing 300 shown.

[0049] In Figure 5 and Figure 7 the portion of the pump housing 300 shown defines an outlet 302 (e.g., outlet 124) of the pump housing 300 and has an outlet fitting 304 located at the outlet 302. The outlet fitting 304 is selectively couplable to the outflow cannula and, as further described in the present invention, cooperates with the outflow cannula 200 to form a rotation prevention mechanism 400 and an axial lock 500 ( Figure 15 shown) that respectively prevent or limit relative rotational movement and relative axial movement between the outflow cannula 200 and the pump housing 300. Figure 5 and Figure 7 the portions of the pump housing 300 shown in Figure 4 are the cap portion 306 of the pump housing 300, which have substantially the same configuration and are coupled to the remainder of the pump housing 300 in substantially the same manner as the cap portion 136 described and shown above. In other embodiments, the outlet fitting 304 and the outlet 302 of the pump housing 300 may be located in a portion of the pump housing 300 other than the cap portion 306.

[0050] The outflow cannula 200 has an inlet end 202 and an outlet end (Figure 5 and Figure 6 (not shown), and defines a fluid passage 204 extending therethrough. The inlet end 202 is connected to the outlet 302 of the pump housing 300 and receives fluid pumped out of the pump housing 300 and exiting the outlet 302. The fluid flows through the fluid passage 204 and is discharged at an outlet end that may be connected to the ascending or descending aorta.

[0051] The outflow cannula 200 includes a flexible fluid conduit 206 extending between the inlet end 202 and the outlet end and at least partially defines the fluid passage 204. The fluid conduit 206 is constructed of a suitable flexible material such that the outflow cannula 200 can be manipulated by an operator (e.g., a surgeon) and conforms to the patient's thoracic cavity. Further referring to Figure 8 and Figure 9 , the outflow cannula 200 also includes a fitting assembly 208 coupled to the fluid conduit 206 at the inlet end 202 of the outflow cannula 200. For example, when the implantable blood pump assembly 100 is implanted in a patient, the fitting assembly 208 is configured to selectively and removably connect to the outlet fitting 304.

[0052] In the illustrated embodiment, the fitting assembly 208 includes an adapter sleeve 210 and a threaded ring 212 rotatably coupled to the adapter sleeve 210. The adapter sleeve 210 and the threaded ring 212 are coaxial with each other, and the threaded ring 212 is configured to rotate relative to the adapter sleeve 210 about the longitudinal axis 214 of the outflow cannula 200 to facilitate coupling the fitting assembly 208 to the outlet connector 304.

[0053] The adapter sleeve 210 has a first end 216 sized to be received within the outlet 302 of the pump housing 300 and a second end 218 disposed within the fluid passage 204 defined by the fluid conduit 206. The adapter sleeve 210 has a suitable rigid structure and is more rigid than the fluid conduit 206 to achieve a secure mechanical connection with the pump housing 300. The adapter sleeve 210 may also be constructed of any suitable material that enables the fitting assembly 208 to perform the functions described in the present invention, such as, but not limited to, titanium, titanium alloy, stainless steel, and plastics having a suitable strength for sterilization and long-term implantability. In the illustrated embodiment, the adapter sleeve 210 is coupled to the fluid conduit 206 by a threaded coupler 220 that presses against the end of the fluid line 206.

[0054] The adapter sleeve 210 also has an annular groove 222 defined in the radially outer surface 224 at the first end 216 of the adapter sleeve 210. As further described in the present invention, an annular seal 226 is placed within the annular groove 222 and is configured to sealingly engage a portion of the outlet fitting 304 when the fitting assembly 208 is connected to the outlet fitting 304.

[0055] The threaded ring 212 includes a cylindrical sleeve 228 having a radially outer surface 230 and a radially inner surface 232. The threaded ring 212 extends from a first free end 234 to a second end 236 located downstream of the first end 234 (i.e., toward the outflow end of the outflow sleeve 200). As Figure 9 shown, the threaded ring 212 extends axially beyond the first end 216 of the adapter sleeve 210.

[0056] The cylindrical sleeve 228 has an inner diameter greater than the outer diameter of the adapter sleeve 210, extends around the first end 216 of the adapter sleeve 210, and encloses the first end of the adapter sleeve. An annular flange portion 238 extends radially inward from the radially inner surface of the sleeve 228 of the threaded ring to the radially outer surface of the adapter sleeve 210 to rotatably couple the threaded ring 212 to the adapter sleeve 210. A locking ring 240 is coupled to the radially outer surface 224 of the adapter sleeve 210 upstream of the annular flange portion 238 (i.e., toward the inflow end 202 of the outflow sleeve 200) and prevents axial movement of the threaded ring 212 relative to the adapter sleeve 210.

[0057] The radially inner surface 232 of the sleeve 228 included in the threaded ring includes threads 242 along an axial portion thereof to facilitate connection of the outflow sleeve 200 to the outlet fitting 304. The radially outer surface 230 of the sleeve 228 of the threaded ring includes a plurality of finger grooves or depressions 244 ( Figure 8 shown) circumferentially arranged around the radially outer surface 230 to facilitate gripping or holding the threaded ring 212. In the illustrated embodiment, the threaded ring 212 also includes a pair of stop tabs 246 ( Figure 8 shown) located in the first end 234. These stop tabs are positioned radially opposite each other and are configured to cooperate with the outlet fitting 304 to provide tactile feedback to the user during connection of the outflow sleeve 200 to the pump housing 300.

[0058] The threaded ring 212 can be constructed of any suitable material capable of enabling the joint assembly 208 to perform the functions described in the present invention, such as, but not limited to, titanium, titanium alloys, stainless steel, and plastics having appropriate strength for sterilization and long-term implantability.

[0059] In the illustrated embodiment, the outflow sleeve 200 also includes a reinforcing sleeve 250 coupled to the fluid conduit 206 at the inflow end 202 of the outflow sleeve 200 and extending toward the outflow end Figure 5 and Figure 9As shown). The reinforcing sleeve 250 has a more rigid structure than the fluid conduit 206 and is configured to prevent the fluid conduit 206 from being overly bent at the inlet end 202 and to effect stress relief of the fluid conduit 206. The reinforcing sleeve 250 of the illustrated embodiment includes a helical spring 252 coupled to a sleeve 254, both surrounding the fluid conduit 206. In other embodiments, the reinforcing sleeve 250 may have a suitable configuration that enables the outlet sleeve 200 to perform the functions described in the present invention. However, in other embodiments, the reinforcing sleeve 250 may also be omitted from the outlet sleeve 200.

[0060] Also referring to Figure 10 and Figure 11 , the outlet joint 304 includes a flange 308 and a sleeve portion 310 that extends axially outwardly and downstream from the flange 308 to a free end 312. The flange 308 extends radially outwardly from the pump housing 300 (specifically from the cap portion 306) and includes a radially outer surface 314 that defines a plurality of depressions or grooves 316. The sleeve 310 of the outlet joint includes a radially outer surface 318 and a radially inner surface 320 that define the outlet 302 of the pump housing 300.

[0061] The radially inner surface 320 of the outlet joint sleeve 310 includes a first axial portion 322 and a second axial portion 324 ( Figure 11 as marked). The first axial portion 322 extends from the flange 308 and is upstream of the second axial portion 324 (i.e., closer to the flow path defined by the pump housing 300). The second axial portion 324 extends from the first axial portion 322 to the free end 312 of the sleeve 310 and defines a sealing surface 326 that sealingly engages the annular seal 226 during insertion of the outlet sleeve 200 into the housing outlet 302. As Figure 11 shown, the second axial portion 324 includes a chamfered edge 328 at the free end of the sleeve 310 that facilitates insertion and engagement with the annular seal 226.

[0062] In the illustrated embodiment, the radially outer surface 318 of the sleeve 310 includes threads 330 that cooperate with the threads 242 of the threaded ring 212 to fasten the joint assembly 208 to the outlet joint 304. Also, in the illustrated embodiment, an annular groove 332 is defined by the flange 308 and extends radially outwardly from the first axial portion 322 of the radially inner surface 320. A washer 334 is placed within the annular groove 332 and sealingly engages the first end of the adapter sleeve 210 when the outlet sleeve 200 is inserted into the outlet 302.

[0063] The outlet fitting 304 can be constructed of any suitable material capable of enabling the outlet fitting to perform the functions described in the present invention. In some embodiments, the outlet fitting 304 is constructed of the same or similar material as the pump housing 300 (e.g., the cap portion 306). Suitable materials from which the outlet fitting 304 can be constructed include, but are not limited to, for example, titanium, titanium alloys, stainless steel, and plastics that can be sterilized and have appropriate strength for long-term implantable performance.

[0064] Figure 12 is an end view of the outflow cannula 200, Figure 13 is an end view of the outlet fitting 304. Figure 14 is a perspective view of the outflow cannula 200 connected to the pump housing 300, while Figure 15 is along Figure 14 the cross-sectional view taken along the "15-15" cutting plane in Figures 12 - 15 . Additionally referring to Figures 12 - 15 , the fitting assembly 208 includes a first member 402 of the anti-rotation mechanism 400 and a first member 502 of the axial lock 500, and the outlet fitting 304 includes a second member 404 of the anti-rotation mechanism 400 and a second member 504 of the axial lock 500. The first and second members 402, 404 of the anti-rotation mechanism 400 are configured to mate with each other and, after mating, prevent or limit the rotation of the outflow cannula 200 relative to the pump housing 300. The first and second members 502, 504 of the axial lock 500 are configured to mate with each other and, after mating, prevent the axial movement of the outflow cannula 200 relative to the pump housing 300.

[0065] Furthermore, as Figure 15 shown, the first and second members 402, 404 of the anti-rotation mechanism 400 are positioned relative to the first and second members 502, 504 of the axial lock 500 such that, during the insertion of the outflow cannula 200 into the housing outlet 302, the first and second members 402, 404 of the anti-rotation mechanism 400 engage with each other prior to the first and second members 502, 504 of the axial lock 500. In other words, during assembly, due to the configuration of the anti-rotation mechanism 400 and the axial lock 500, the outflow cannula 200 is rotationally locked relative to the pump housing 300 before the outflow cannula 200 is axially fixed or locked to the pump housing 300. Thus, during the implantation of the blood pump assembly 100, the outflow cannula 200 is rotationally locked or fixed before the outflow cannula 200 is axially locked or fastened to the pump housing 300, and thus the rotation of the outflow cannula is prevented after the operation. Therefore, the anti-rotation mechanism 400 and the axial lock 500 help prevent excessive rotation and torsion of the outflow cannula 200 after the operation, and the risk of narrowing or collapse of the fluid conduit 206 of the outflow cannula 200 due to such postoperative rotation and torsion.

[0066] In addition, in the illustrated embodiment, when the first and second members 402, 404 of the anti-rotation mechanism 400 are not axially aligned, the first and second members 402, 404 of the anti-rotation mechanism 400 prevent the engagement of the first and second members 502, 504 of the axial lock 500. For example, as Figure 16 shown, if the first and second members 402, 404 of the anti-rotation mechanism 400 are not axially aligned, they will prevent the outflow cannula 200 from being inserted into the housing outlet 302, thereby preventing the first and second members 502, 504 of the axial lock 500 from engaging with each other. The first and second members 402, 404 of the anti-rotation mechanism 400 allow the outflow cannula 200 to be inserted into the housing outlet 302 only when the first and second members 402, 404 of the anti-rotation mechanism 400 are axially aligned with each other, as Figure 17 shown. In this way, the anti-rotation mechanism 400 ensures that the first and second members 402, 404 of the anti-rotation mechanism 400 engage before the first and second members 502, 504 of the axial lock 500, thereby reducing the risk of jamming of the paired members in the case where the anti-rotation mechanism 400 is not engaged.

[0067] In addition, the first and second members 402, 404 of the anti-rotation mechanism 400 are arranged relative to each other such that the outflow cannula 200 can be selectively coupled to the outlet fitting 304 in one of a discrete, finite number of directions. In some embodiments, for example, the anti-rotation mechanism 400 allows the connection of the joint assembly 208 to the outlet fitting 304 in at least 2 directions, at least 4 directions, at least 10 directions, between 1 and 100 directions, between 1 and 50 directions, between 1 and 40 directions, between 1 and 30 directions, between 1 and 20 directions, between 1 and 10 directions, between 1 and 5 directions, between 2 and 20 directions, between 2 and 10 directions, and between 2 and 5 directions. In the illustrated embodiment, the anti-rotation mechanism 400 allows the joint assembly 208 to be connected to the outlet fitting 304 in one of 4 discrete directions. In other embodiments, the anti-rotation mechanism 400 may allow the joint assembly 208 and the outlet fitting 304 to be coupled in any other number of directions. By limiting the number of directions in which the joint assembly 208 is connected to the outlet fitting 304, the anti-rotation mechanism 400 further helps to prevent excessive rotation and torsion of the outflow cannula 200, especially during the implantation of the blood pump assembly 100, by limiting the degree to which the outflow cannula 200 can rotate relative to the pump housing 300 while still remaining connected.

[0068] In the illustrated embodiment, the first end 216 of the adapter sleeve 210 includes a first member 402 of the anti-rotation mechanism 400, and the outlet fitting 304 includes a second member 404 of the anti-rotation mechanism 400. More specifically, in the illustrated embodiment, the first member 402 of the anti-rotation mechanism 400 includes a plurality of longitudinally extending grooves 256, and the second member of the anti-rotation mechanism 400 includes a plurality of longitudinally extending splines 336.

[0069] The grooves 256 are defined in the radially outer surface 224 of the adapter sleeve 210 at the first end 216. The grooves 256 extend downstream from the first end 216 (i.e., toward the second end 218 of the adapter sleeve 210) to an annular groove 222 in which the annular seal 226 is located. The plurality of grooves 256 are circumferentially spaced apart around the radially outer surface 224 of the adapter sleeve 210 by a distance corresponding to the circumferential spacing of the plurality of splines 336. The illustrated embodiment includes 4 grooves 256 spaced at 90° intervals relative to adjacent grooves 256. In other embodiments, the fitting assembly 208 may include more or fewer than 4 grooves, such as, but not limited to, at least 1 groove, at least 2 grooves, at least 4 grooves, at least 10 grooves, between 1 and 100 grooves, between 1 and 50 grooves, between 1 and 40 grooves, between 1 and 30 grooves, between 1 and 20 grooves, between 1 and 10 grooves, between 1 and 5 grooves, between 2 and 20 grooves, between 2 and 10 grooves, and between 2 and 5 grooves. Additionally, although the plurality of grooves 256 are shown and described as being equally spaced around the radially outer surface 224 of the adapter sleeve 210, in other embodiments, the plurality of grooves 256 may be unequally spaced. For example, 4 grooves may be arranged such that each groove 256 is spaced 60° from one adjacent groove 256 and 120° from another adjacent groove 256. This can serve to further limit the number of directions in which the fitting assembly 208 can be connected to the outlet fitting 304.

[0070] Further, in the illustrated embodiment, the grooves 256 are wrench nut slots configured to engage a wrench. In particular, each groove 256 is sized and shaped to receive a leg or spline of a wrench to apply torque to the adapter sleeve 210 during installation of the outflow cannula 200. Thus, the grooves 256 perform multiple functions in the installation of the blood pump assembly 100 and reduce the need for additional components to achieve these functions, thereby reducing the size, number, and cost of components of the outflow cannula 200. In other embodiments, the grooves 256 may be configured as grooves other than wrench nut slots.

[0071] A plurality of splines 336 are located on the radially inner surface 320 of the outlet adapter sleeve 310, specifically along a first axial portion 322 of the radially inner surface 320, and are configured to matingly engage with a plurality of grooves 256. As Figure 13 shown, each spline 336 projects radially inwardly from the radially inner surface 320 and extends further radially inwardly than a second axial portion 324 of the radially inner surface 320.

[0072] Similar to the grooves 256, the plurality of splines 336 are circumferentially spaced apart around the radially inner surface 320 of the sleeve 310 by a distance corresponding to the circumferential spacing of the plurality of grooves 256. The illustrated embodiment includes 4 splines 336 spaced at 90° intervals relative to adjacent splines 336. In other embodiments, the outlet adapter 304 may include more or fewer than 4 splines, such as including but not limited to at least 1 spline, at least 2 splines, at least 4 splines, at least 10 splines, between 1 spline and 100 splines, between 1 spline and 50 splines, between 1 spline and 40 splines, between 1 spline and 30 splines, between 1 spline and 20 splines, between 1 spline and 10 splines, between 1 spline and 5 splines, between 2 splines and 20 splines, between 2 splines and 10 splines, and between 2 splines and 5 splines. Additionally, although the splines 336 are shown and described as being equally spaced around the radially inner surface 320 of the sleeve 310 of the outlet adapter, in other embodiments, the splines 336 may also be spaced at unequal intervals. For example, 4 splines may be arranged such that each spline 336 is spaced 60° from an adjacent spline 336 and 120° from another adjacent spline 336. This can serve to further limit the number of directions in which the adapter assembly 208 can be connected to the outlet adapter 304.

[0073] The size and shape of each spline 336 are complementary to one of the plurality of grooves 256. In the illustrated embodiment, each spline 336 has an arcuate or circular cross-section, while each groove 256 has a complementary arcuate or circular cross-section. The arcuate shape of the splines 336 and grooves 256 is beneficial for reducing shear forces between components (e.g., the adapter sleeve 210 and the outlet adapter 304) that result from rotational forces applied to the components during and / or after installation of the blood pump assembly 100 (i.e., after surgery). Additionally, since the splines 336 and grooves 256 are circumferentially spaced, the rotational forces applied to the components of the blood pump assembly 100 have the effect of recentering or realigning the adapter sleeve 210 and the outlet adapter 304.

[0074] Multiple splines 336 can be integrally constructed with the outlet fitting 304. That is, the splines 336 can be integrally manufactured and formed with the outlet fitting 304 during the manufacturing process of the outlet fitting 304 (e.g., by molding, machining, milling, etc.). Alternatively, multiple splines 336 can be formed on a plug (e.g., an annular plug) sized and shaped to be received within the sleeve 310 of the outlet fitting.

[0075] In the illustrated embodiment, the first and second members 402, 404 of the anti-rotation mechanism 400 are configured to substantially prevent any rotation of the outflow sleeve 200 relative to the pump housing 300 about the longitudinal axis 214. For example, the arc length or circumferential width of each groove 256 is substantially equal to but slightly greater than the arc length or circumferential width of each spline 336, such that the groove 256 provides sufficient clearance for the spline 336 to be inserted into the groove 256. Once the spline 336 is inserted into the groove 256, rotation of the outflow sleeve 200 relative to the pump housing 300 is substantially prevented due to the lateral engagement of the spline 336 with the groove 256. For example, in the illustrated embodiment, the spline 336 and the groove 256 can limit the relative rotation of the outflow sleeve 200 and the pump housing 300 to less than 2°, less than 1°, or even less than 0.5°. In other embodiments, the first and second members 402, 404 of the anti-rotation mechanism 400 can be configured to allow limited rotation of the outflow sleeve 200 relative to the pump housing 300. In some embodiments, for example, the first and second members 402, 404 of the anti-rotation mechanism 400 can be configured to allow the outflow sleeve 200 (specifically, the adapter sleeve 210 and the fluid conduit 206) to rotate relative to the pump housing 300 by up to 10° (±5° from the center), up to 20° (±10° from the center), up to 30° (±15° from the center), up to 40° (±20° from the center), up to 50° (±25° from the center), up to 60° (±30° from the center), or even up to 90° (±45° from the center). By way of example, the arc length or circumferential width of the groove 256 can be sized to be a suitable amount larger than the arc length or circumferential width of the spline 336 to achieve the desired amount of controlled rotation of the outflow sleeve 200 relative to the pump housing 300. In such an embodiment, the threaded ring 212 will remain axially and rotationally fixed relative to the outlet fitting 304, while the adapter sleeve 210 and the fluid conduit 206 will allow rotation by a limited amount. Allowing limited rotation of the outflow sleeve 200 relative to the pump housing 300 can provide additional post-operative strain relief for the outflow sleeve 200, for example, to accommodate patient movement.

[0076] In the present embodiment, the first and second members 502, 504 of the axial lock include complementary threads. Specifically, the first member 502 of the axial lock 500 includes threads 242 on the radially inner surface 232 of the sleeve 228 of the threaded ring, while the second member 504 of the axial lock 500 includes threads 330 on the radially outer surface 318 of the sleeve 310 of the outlet fitting.

[0077] As described above, the members of the anti-rotation mechanism 400 and the axial lock 500 are configured such that during insertion of the outflow sleeve 200 into the housing outlet 302, the members of the anti-rotation mechanism 400 engage each other before the members of the axial lock 500 engage each other. In the illustrated embodiment, this is achieved based on the positioning of the grooves 256, splines 336, and threads 242, 330. That is, the axial spacing of the splines 336 relative to the threads 330 on the radially outer surface 318 of the sleeve 310 of the outlet fitting, and the axial spacing of the grooves 256 relative to the threads 242 on the radially inner surface 232 of the sleeve 228 of the threaded ring, enable the splines 336 and the grooves 256 to engage each other and form the anti-rotation mechanism 400 before the threads 242, 330 engage each other. As Figure 18 and 19 shown, for example, when the outflow sleeve 200 is inserted into the housing outlet 302, the splines 336 of the outlet fitting 304 will initially engage the grooves 256 of the adapter sleeve 210 before the threads 242, 330 engage each other. Additionally, if the splines 336 and the grooves 256 are not axially aligned (e.g., as Figure 16 shown), the splines 336 will engage the first end 216 of the adapter sleeve 210 and prevent further insertion of the outflow sleeve 200 into the housing outlet 302. This engagement between the first end 216 of the adapter sleeve 210 and the splines 336 of the outlet fitting 304 can provide useful tactile feedback to the operator, e.g., indicating that the adapter sleeve 210 is partially inserted into the outlet fitting 304 and the splines 336 and the grooves 256 are not axially aligned.

[0078] When the splines 336 are axially aligned with the grooves 256 (e.g., as Figure 17 shown), the outflow sleeve 200 can be further inserted into the housing outlet 302 such that the splines 336 are received within and engage the grooves 256. As Figure 19As shown, the spline 336 engages the groove 256 before the multiple threads 242, 330 engage each other. Continuing to insert the outflow sleeve 200 into the housing outlet 302 causes the threads 242, 330 to engage each other. When the multiple threads 242, 330 initially engage each other, the multiple threads 242, 330 will prevent the outflow sleeve 200 from continuing to move axially relative to the pump housing 300. The initial engagement of the threads 242, 330 provides useful tactile feedback to the operator, for example, providing an indication of the relative axial position of the outflow sleeve 200 and the pump housing 300 and indicating that the threads 242, 330 have engaged, allowing the thread ring 212 to be rotated. Rotation of the thread ring 212 causes the threads 242, 330 to engage each other and provides a mechanical advantage when further inserting the outflow sleeve 200 into the housing outlet 302 and causing the annular seal 226 to engage the sealing surface 326. In the illustrated embodiment, continued rotation of the thread ring 212 causes the stop tab 246 on the thread ring 212 to engage the groove 316 in the flange 308 of the outlet fitting 304. Engagement of the stop tab 246 with the groove in the flange 308 provides tactile feedback to the operator indicating that the outflow sleeve 200 has been inserted into the housing outlet 302 to a sufficient depth.

[0079] In the illustrated embodiment, the annular seal 226 is positioned relative to the groove 256 and the spline 336 such that the annular seal 226 engages the sealing surface 326 after the spline 336 engages the groove 256 (i.e., after the first and second members 402, 404 of the anti-rotation mechanism 400 engage each other). Additionally, in the illustrated embodiment, the annular seal 226 is positioned relative to the multiple threads 242, 330 and the sealing surface 326 such that the annular seal 226 engages the sealing surface 326 before the threads 242, 330 engage each other (i.e., before the first and second members 502, 504 of the axial lock 500 engage each other). In other embodiments, the annular seal 226 may be positioned relative to the threads 242, 330 and the sealing surface 326 such that the annular seal 226 engages the sealing surface 326 only after the multiple threads 242, 330 engage each other (i.e., after the first and second members 502, 504 of the axial lock 500 engage each other).

[0080] Although the components of the anti-rotation mechanism 400 are shown and described as splines and grooves, it should be understood that the components of the anti-rotation mechanism 400 are not limited to the splines and grooves described herein. In particular, the components of the anti-rotation mechanism 400 can include any suitable components capable of enabling the anti-rotation mechanism 400 to perform the functions as described herein, for example, including but not limited to tabs, slots, protrusions, keyed components, bayonet connections, stoppers, serrations, knurling, anti-slip strips, teeth (such as Hirth joints), clutch mechanisms, and combinations thereof. As used in the present invention, the term "clutch mechanism" includes, for example and without limitation, elements that form a radial compressive force on one or both of the adapter sleeve 210 and the outlet joint 304 as a result of a tensile load on one or both of the adapter sleeve 210 and the outlet joint 304 (e.g., a push-on joint), and elements that form a radial and / or axial compressive force on one or both of the adapter sleeve 210 and the outlet joint 304 as a result of the engagement of the axial lock 500 (e.g., a bolt connection with sufficient friction at the docking interface).

[0081] Similarly, although the components of the axial lock 500 are shown and described as complementary threads, it should be understood that the components of the axial lock 500 are not limited to the threads described in the present invention. In particular, the components of the axial lock 500 can include any suitable components capable of enabling the axial lock 500 to perform the functions as described in the present invention, for example, including but not limited to snap-fit components, crimped components, bayonet connections, stoppers, cam and groove connections, claw and flange connections, push-in fittings, and combinations thereof.

[0082] Furthermore, although the first component 402 of the anti-rotation mechanism 400 is shown and described as being part of the adapter sleeve 210, and the second component 404 of the anti-rotation mechanism 400 is shown and described as being part of the outlet joint 304, it should be understood that the first and second components 402, 404 of the anti-rotation mechanism 400 can be reversed in other embodiments. That is, the adapter sleeve 210 can include the second component 404 of the anti-rotation mechanism 400, while the outlet joint 304 can include the first component 402 of the anti-rotation mechanism 400. However, in other embodiments, the first and second components 402, 404 of the anti-rotation mechanism 400 can be located on the components of the outflow sleeve 200 and the pump housing 300, rather than on the adapter sleeve 210 and the outlet joint 304. Similarly, the first and second components 502, 504 of the axial lock 500 can also be reversed in other embodiments. That is, the threaded ring 212 can include the second component 504 of the axial lock 500, while the outlet joint 304 can include the first component 502 of the axial lock. In some other embodiments, the first and second components 502, 504 of the axial lock 500 can be located on the components of the outflow sleeve 200 and the pump housing 300, rather than on the threaded ring 212 and the outlet joint 304.

[0083] Figure 20 A flowchart showing one embodiment of a method 2000 for installing an implantable blood pump (e.g., blood pump assembly 100). In the illustrated embodiment, the method 2000 includes 2002 providing an outflow cannula (e.g., outflow cannula 200) that includes a fitting assembly (e.g., fitting assembly 208), the fitting assembly including a first member of an anti-rotation mechanism (e.g., first member 402 of anti-rotation mechanism 400) and a first member of an axial lock (e.g., first member 502 of axial lock 500). The method 2000 further includes 2004 providing a blood pump (e.g., blood pump 102) that includes a housing (e.g., blood pump housing 300) defining an inlet, an outlet, and a flow path extending from the inlet to the outlet, wherein the housing includes an outlet fitting (e.g., outlet fitting 304) that includes a second member of an anti-rotation mechanism (e.g., second member 402 of anti-rotation mechanism 400) and a second member of an axial lock (e.g., second member 504 of axial lock 500). Method 2000 further includes 2006 aligning the first member of the anti-rotation mechanism with the second member of the anti-rotation mechanism, and 2008 inserting the outflow cannula into the housing outlet such that the first and second members of the anti-rotation mechanism engage each other prior to the first and second members of the axial lock. The anti-rotation mechanism restricts rotation of the outflow cannula relative to the pump housing. Method 2000 further includes 2010 engaging the first member of the axial lock with the second member of the axial lock, thereby causing the axial lock to prevent axial movement of the outflow cannula relative to the pump housing.

[0084] Although some of the steps of the example method are numbered, this numbering does not indicate that these steps must be performed in the order listed. Thus, the specific steps need not be performed in the exact order in which they are presented, unless the description specifically requires such an order. These steps may be performed in the order listed, or in other suitable orders.

[0085] As described in the present invention, the disclosed implantable blood pump assembly provides more advantages than previous ventricular assist device designs. For example, embodiments of the implantable blood pump assembly disclosed in the present invention include an outlet fitting and an outflow cannula that cooperate to form an anti-rotation mechanism and an axial lock. The various components of the anti-rotation mechanism and the axial lock are positioned to allow the blood pump assembly to be assembled in a certain order to reduce the risk of the outflow cannula being overly rotated or twisted during and after placement of the blood pump assembly (i.e., after surgery). For example, the components of the anti-rotation mechanism are configured to engage each other prior to the components of the axial lock, thereby ensuring that the components of the anti-rotation mechanism are engaged (and thus preventing rotation) before the axial lock engages. Additionally, in some embodiments, the anti-rotation mechanism only allows the outflow assembly and the outlet fitting to be connected in a non-continuous direction, thereby limiting the amount of rotation of the outflow cannula relative to the pump housing during installation. Further, in some embodiments, the anti-rotation mechanism utilizes existing structural features of the outflow cannula for other purposes (e.g., wrench grooves for installing the outflow cannula) to achieve the anti-rotation function, thereby reducing the need for additional or redundant components on the outflow cannula and reducing the size and cost of the outflow cannula.

[0086] Although the embodiments and examples disclosed in the present invention have been described with reference to specific embodiments, it should be understood that these embodiments and examples only illustrate the principles and applications of the present invention. Therefore, it should be understood that various modifications can be made to the illustrative embodiments and examples, and other arrangements can be designed without departing from the spirit and scope of the present invention as defined by the claims. Accordingly, this application is intended to cover modifications and variations of these embodiments and their equivalents.

[0087] This written description uses examples to disclose the subject matter of the present invention, including the best mode, and also enables any person skilled in the art to practice the subject matter of the present invention, including making and using any device or system and performing any incorporated method. The patentable scope of the subject matter of the present invention is defined by the claims and may include other examples that occur to those skilled in the art. If these other examples have structural elements that are identical to the literal language of the claims or if they contain equivalent structural elements that are not materially different from the literal language of the claims, then these other examples fall within the scope of the claims.

Claims

1. An implantable blood pump assembly, comprising: a housing that defines an inlet, an outlet, and a flow path extending from the inlet to the outlet, the housing including an outlet fitting; a rotor positioned within the flow path and operable to pump blood from the inlet to the outlet; a stator positioned within the housing and operable to drive the rotor; an outflow cannula that includes a fitting assembly configured for removably mechanically coupling to the outlet fitting, wherein the fitting assembly includes a first member of an anti-rotation mechanism and a first member of an axial lock; wherein the outlet fitting includes a second member of the anti-rotation mechanism and a second member of the axial lock, and the second member of the axial lock is closer to the free end of the outlet fitting than the second member of the anti-rotation mechanism; wherein during insertion of the outflow cannula into the housing outlet, the first member and the second member of the anti-rotation mechanism are positioned to engage each other prior to the first member and the second member of the axial lock and prevent rotation of the outlet fitting and the outflow cannula relative to each other.

2. The implantable blood pump assembly according to claim 1, wherein the second member of the anti-rotation mechanism includes a plurality of longitudinally extending splines positioned on a radially inner surface of the outlet fitting, and wherein the plurality of splines are circumferentially spaced around the radially inner surface of the outlet fitting.

3. The implantable blood pump assembly according to claim 2, wherein the first member of the anti-rotation structure includes a plurality of longitudinally extending grooves defined in a radially outer surface of a sleeve to the fitting assembly, and wherein the plurality of grooves are circumferentially spaced around the radially outer surface of the sleeve at a distance corresponding to the circumferential spacing of the plurality of splines.

4. The implantable blood pump assembly according to claim 3, wherein the plurality of grooves are wrench nut slots configured for engagement with a wrench.

5. The implantable blood pump assembly according to claim 1, wherein after engagement of the first member and the second member of the anti-rotation mechanism, limited rotation of the outflow cannula relative to the outlet fitting is allowed.

6. The implantable blood pump assembly according to claim 1, wherein the first member and the second member of the axial lock include complementary threads.

7. The implantable blood pump assembly according to claim 1, wherein the first member and the second member of the anti-rotation mechanism prevent engagement of the first member and the second member of the axial lock when the first member and the second member of the anti-rotation mechanism are axially misaligned.

8. The implantable blood pump assembly according to claim 1, wherein the first member and the second member of the anti-rotation mechanism are arranged relative to each other such that the outflow cannula can be selectively coupled to the outlet fitting in one of at least 4 discrete directions.

9. The implantable blood pump assembly according to claim 1, wherein the fitting assembly further includes an annular seal, and wherein the outlet fitting includes a sealing surface that sealingly engages the seal during insertion of the outflow cannula into the outlet of the housing.

10. The implantable blood pump assembly according to claim 9, wherein the seal is positioned such that the seal engages a sealing surface after the first and second members of the anti-rotation mechanism are engaged with each other.

11. The implantable blood pump assembly according to claim 10, wherein the seal is positioned such that the seal engages a sealing surface before the first and second members of the axial lock are engaged with each other.

12. The implantable blood pump assembly according to claim 10, wherein the seal is positioned such that the seal engages a sealing surface after the first and second members of the axial lock are engaged with each other.

13. The implantable blood pump assembly according to claim 1, wherein the outflow cannula has an inflow end and an outflow end, and includes a flexible fluid conduit extending between the inflow end and the outflow end, wherein the fitting assembly is coupled to the fluid conduit at the inflow end of the outflow cannula.

14. The implantable blood pump assembly according to claim 1, wherein the fitting assembly comprises: An adapter sleeve, wherein the adapter sleeve has a first end sized to be received within the housing outlet and a second end placed within the fluid conduit of the outflow cannula, wherein the first end of the adapter sleeve includes the first member of the anti-rotation mechanism; And A threaded ring rotatably coupled to the adapter sleeve and including the first member of the axial lock.

15. An implantable blood pump assembly, comprising: A housing defining an inlet, an outlet, and a flow path extending from the inlet to the outlet, the housing including an outlet fitting; A rotor positioned within the flow path and operable to pump blood from the inlet to the outlet; A stator positioned within the housing and operable to drive the rotor; An outflow cannula including a fitting assembly configured for removably mechanically coupling to the outlet fitting; Wherein the fitting assembly comprises: An adapter sleeve, wherein the adapter sleeve includes one of: (i) a plurality of longitudinally extending grooves or (ii) a plurality of longitudinally extending splines; And A threaded ring rotatably coupled to the adapter sleeve and including a first thread; Wherein the outlet fitting includes one of: (i) a plurality of longitudinally extending grooves or (ii) a plurality of longitudinally extending splines; and a second thread configured to threadedly engage the first thread, wherein the plurality of splines are configured for mating engagement with the plurality of grooves to prevent relative rotation between the outflow cannula and the pump housing, Wherein during insertion of the outflow cannula into the housing outlet, the plurality of grooves and the plurality of splines are positioned to engage each other prior to engagement of the first thread and the second thread and prevent rotation of the outlet fitting and the outflow cannula relative to each other.

16. The implantable blood pump assembly according to claim 15, wherein the plurality of grooves and the plurality of splines prevent engagement of the first thread and the second thread when the plurality of grooves and the plurality of splines are axially misaligned.

17. The implantable blood pump assembly according to claim 15, wherein the plurality of grooves and the plurality of splines are arranged relative to each other such that the outflow cannula can be selectively coupled to the outlet fitting in one of a discrete number of directions.

18. The implantable blood pump assembly according to claim 15, wherein the plurality of grooves are wrench nut slots configured to engage a wrench.

19. A method of assembling an implantable blood pump assembly, the method comprising: providing an outflow cannula including a fitting assembly, the fitting assembly including a first member of an anti-rotation mechanism and a first member of an axial lock; providing a blood pump including a housing, the housing defining an inlet, an outlet, and a flow path extending from the inlet to the outlet, wherein the housing includes an outlet fitting, the outlet fitting including a second member of the anti-rotation mechanism and a second member of the axial lock, the second member of the axial lock being closer to the free end of the outlet fitting than the second member of the anti-rotation mechanism; aligning the first member of the anti-rotation mechanism with the second member of the anti-rotation mechanism; inserting the outflow cannula into the housing outlet such that the first and second members of the anti-rotation mechanism engage each other prior to and in a manner that prevents relative rotation between the outlet fitting and the outflow cannula, and the anti-rotation mechanism restricts rotation of the outflow cannula relative to the pump housing, and engaging the first member of the axial lock with the second member of the axial lock such that the axial lock prevents axial movement of the outflow cannula relative to the pump housing.

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