A percutaneous circulatory assist system capable of reducing hemolysis

Abstract

The percutaneous circulatory assist device includes a housing having an inlet and an outlet. A shaft is rotatably fixed relative to the housing. An impeller is disposed within the housing and rotatably supported by the shaft. The impeller is configured to rotate relative to the shaft and housing to cause blood to flow into the inlet, through the housing, and out the outlet. A keeper is coupled to the shaft distal to the impeller, the keeper restraining axial movement of the impeller relative to the shaft.

Description

Technical Field

[0001] The present disclosure relates to a percutaneous circulatory assist system. More specifically, the present disclosure relates to a percutaneous circulatory assist device capable of reducing hemolysis.

Background Art

[0002] Percutaneous circulatory assist devices such as blood pumps can provide temporary assistance for up to about several weeks in patients with reduced cardiac function or cardiac output. However, the operation of such blood pumps can cause a certain degree of hemodynamic shear, which can result in hemolysis (i.e., rupture or destruction of blood cells). A high hemolysis rate can cause acute kidney injury or other complications. Therefore, there is a need for an improved blood pump capable of reducing hemolysis.

Summary of the Invention

[0003] In Example 1, the percutaneous circulatory assist device includes a housing, a shaft defined, and an impeller disposed within the housing and rotatably supported by the shaft, the impeller being configured to rotate with respect to the shaft and the housing so that blood flows through the housing, and a keeper coupled to the shaft distally with respect to the impeller, the keeper suppressing the axial movement of the impeller with respect to the shaft. Fixed to

[0004] In Example 2, in the percutaneous circulatory assist device of Example 1, the keeper functions as a thrust bearing. In Example 3, in the percutaneous circulatory assist device according to any one of Examples 1 to 2, the percutaneous circulatory assist device is provided with a support portion that couples the shaft to the housing and is disposed distally with respect to the impeller.

[0005] In Example 4, any of the percutaneous circulatory assist devices of Examples 1 to 3 further includes a motor operable to rotationally drive an impeller with respect to a shaft and a housing so that blood flows through the housing.

[0006] In Example 5, any of the percutaneous circulatory assist devices of Examples 1 to 4 further includes a thrust bearing that couples the impeller to the housing. In Example 6, in the percutaneous circulatory assist device of Example 5, the thrust bearing is a proximal thrust bearing, and the percutaneous circulatory assist device further includes a distal thrust bearing that couples the impeller to the housing.

[0007] In Example 7, any of the percutaneous circulatory assist devices of Examples 1 to 6 further includes an impeller assembly, the impeller assembly including an impeller and an inner tube rotatably supported by a shaft, the impeller being Fixed to defined.

[0008] In Example 8, the percutaneous circulatory assist device of Example 7 further includes a motor, a drive magnet operably coupled to the motor, and a driven magnet operably coupled to the drive magnet, the inner tube and the impeller being Fixed to defined, and the motor is operable to rotationally drive the impeller via the drive magnet and the driven magnet so that blood flows through the housing.

[0009] In Example 9, the percutaneous circulatory assist device includes a motor, a housing, a shaft Fixed to defined, a keeper coupled to the shaft, and an impeller disposed within the housing, rotatably supported by the shaft, and axially constrained with respect to the shaft by the keeper, the motor being operable to rotationally drive the impeller with respect to the housing so that blood flows through the housing.

[0010] In Example 10, in the percutaneous circulatory assist device of Example 9, the keeper functions as a thrust bearing. In Example 11, in the percutaneous circulatory assist device of either Example 9 or 10, the keeper is disposed distally with respect to the impeller.

[0011] In Example 12, in the percutaneous circulatory assist device of any one of Examples 9 to 11, the percutaneous circulatory assist device is provided with a support portion that couples the shaft to the housing and is disposed distally with respect to the impeller.

[0012] In Example 13, the percutaneous circulatory assist device of any one of Examples 9 to 12 further includes a thrust bearing coupled to the impeller. In Example 14, the percutaneous circulatory assist device of any one of Examples 9 to 13 further includes an impeller assembly, the impeller assembly including an impeller and an inner tube rotatably supported by a shaft, the impeller being the inner tube Fixed to is defined.

[0013] In Example 15, the percutaneous circulatory assist device of Example 14 further includes a drive magnet operably coupled to the motor and a driven magnet operably coupled to the drive magnet, the inner tube and the impeller being the driven magnet Fixed to is defined, and the motor is operable to rotationally drive the impeller via the drive magnet and the driven magnet so that blood flows through the housing.

[0014] In Example 16, the percutaneous circulatory assist device includes a housing having an inlet and an outlet, the housing Fixed toA defined shaft, an impeller disposed within a housing and rotatably supported by the shaft, the impeller configured to rotate relative to the shaft and the housing such that blood flows into an inlet and out of an outlet through the housing, and a keeper coupled to the shaft distal to the impeller, the keeper preventing axial movement of the impeller relative to the shaft.

[0015] In Example 17, in the percutaneous circulatory assist device of Example 16, the keeper functions as a thrust bearing. In Example 18, in the percutaneous circulatory assist device of Example 16, the percutaneous circulatory assist device is provided with no support portion that couples the shaft to the housing and is disposed distal to the impeller.

[0016] In Example 19, the percutaneous circulatory assist device of Example 16 further comprises a motor operable to rotationally drive the impeller relative to the shaft and the housing such that blood flows into an inlet and out of an outlet through the housing.

[0017] In Example 20, in the percutaneous circulatory assist device of Example 16, the device further comprises a thrust bearing that couples the impeller to the housing. In Example 21, in the percutaneous circulatory assist device of Example 20, the thrust bearing is a proximal thrust bearing, and the percutaneous circulatory assist device further comprises a distal thrust bearing that couples the impeller to the housing.

[0018] In Example 22, the percutaneous circulatory assist device of Example 16 further comprises an impeller assembly, the impeller assembly including the impeller and an inner tube rotatably supported by the shaft, the impeller being defined by the inner tube Fixed to is defined.

[0019] In Example 23, the percutaneous circulatory assist device of Example 22 further includes a motor, a drive magnet operably coupled to the motor, and a driven magnet operably coupled to the drive magnet. The inner tube and the impeller are defined by the driven magnet Fixed to and the motor is operable to rotationally drive the impeller via the drive magnet and the driven magnet so that blood flows into the inlet and outflows from the outlet through the housing.

[0020] In Example 24, the percutaneous circulatory assist device includes a motor, a housing having an inlet and an outlet, and a shaft Fixed to defined in the housing, a keeper coupled to the shaft, and an impeller disposed in the housing, rotatably supported by the shaft, and axially constrained with respect to the shaft by the keeper. The motor is operable to rotationally drive the impeller with respect to the housing so that blood flows into the inlet and outflows from the outlet through the housing.

[0021] In Example 25, in the percutaneous circulatory assist device of Example 24, the keeper functions as a thrust bearing. In Example 26, in the percutaneous circulatory assist device of Example 24, the keeper is disposed distally with respect to the impeller.

[0022] In Example 27, in the percutaneous circulatory assist device of Example 24, the percutaneous circulatory assist device is provided with a support portion that couples the shaft to the housing and is disposed distally with respect to the impeller.

[0023] In Example 28, the percutaneous circulatory assist device of Example 24 further includes a thrust bearing coupled to the impeller. In Example 29, in the percutaneous circulatory assist device of Example 28, the thrust bearing is a proximal thrust bearing, and the percutaneous circulatory assist device further includes a distal thrust bearing coupled to the impeller.

[0024] In Example 30, the percutaneous circulatory assist device of Example 24 further includes an impeller assembly, and the impeller assembly includes an impeller and an inner tube rotatably supported by a shaft. The impeller is disposed within the inner tube Fixed to is defined.

[0025] In Example 31, the percutaneous circulatory assist device of Example 30 further includes a drive magnet operably coupled to a motor and a driven magnet operably coupled to the drive magnet. The inner tube and the impeller are defined in association with the driven magnet Fixed to and the motor is operable to rotationally drive the impeller via the drive magnet and the driven magnet such that blood flows into the inlet and outflows from the outlet through the housing.

[0026] In Example 32, a method of manufacturing a percutaneous circulatory assist device includes coupling a shaft to a housing such that the shaft is defined relative to the housing, disposing an impeller within the housing and coupling the impeller to the shaft such that the impeller is rotatably supported by the shaft, coupling a keeper to the shaft such that the impeller is axially constrained relative to the shaft, and operably coupling the impeller to a motor. Fixed to

[0027] In Example 33, the method of Example 32 further includes coupling a thrust bearing to the shaft and the housing prior to coupling the impeller to the shaft. In Example 34, the method of Example 32 further includes coupling an inner tube to the impeller such that the impeller is defined relative to the inner tube, and coupling the impeller to the shaft includes coupling the inner tube and the impeller together to the shaft. Fixed to

[0028] In Example 35, the method of Example 34 includes the driven magnet being defined relative to the inner tube Fixed to ​​further comprising the step of coupling a driven magnet to the inner tube as set, coupling the inner tube and the impeller together to the shaft includes coupling the inner tube, the driven magnet, and the impeller together to the shaft.

[0029] While multiple embodiments have been disclosed, still other embodiments of the present invention will become apparent to those skilled in the art from the following detailed description, which illustrates and describes exemplary embodiments of the invention. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive.

Brief Description of the Drawings

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[0031] The present invention can accept various modifications and alternative forms. Specific embodiments are shown by way of example in the drawings and are described in detail below. However, the intention is not to limit the present invention to the specific embodiments described. On the contrary, the present invention is intended to embrace all modifications, equivalents, and alternative forms included within the scope of the present invention as defined by the appended claims.

[0032] FIG. 1 shows a side cross-sectional view of an exemplary mechanical circulatory assist device 100 (also referred to interchangeably herein as a "blood pump") according to an embodiment of the subject matter disclosed herein. The blood pump 100 can form part of a percutaneous circulatory assist system, along with a guide wire and introducer sheath (not shown). More specifically, the guide wire and introducer sheath can enable percutaneous delivery of the blood pump 100 to a target location within a patient, such as within the patient's heart.

[0033] Continuing to refer to FIG. 1 and further referring to FIG. 2, the blood pump 100 generally includes an impeller housing 102 and a motor housing 104. The impeller housing 102 and / or the motor housing 104 can be made from various materials such as stainless steel or nitinol. In some embodiments, the impeller housing 102 and the motor housing 104 can be made integrally or monolithically. In other embodiments, the impeller housing 102 and the motor housing 104 can be separate components configured to be removably or permanently coupled. In some embodiments, the blood pump 100 may not include a separate motor housing 104, and the impeller housing 102 can be directly coupled to a motor 122 described below, or the motor housing 104 can be made integrally with the motor 122 described below.

[0034] The impeller housing 102 houses an impeller assembly 106 therein. The impeller assembly 106 generally includes an inner tube 108 (e.g., a hypodermic tube made of stainless steel) and an impeller 110 having one or more impeller blades 112. The inner tube 108 and the impeller 110 rotate together relative to the impeller housing 102 for pumping blood through the blood pump 100. More specifically, the impeller 110 causes blood to flow from a blood inlet 114 formed on the impeller housing 102, through the impeller housing 102, and out through a blood outlet 116 formed on the impeller housing 102. As shown in FIGS. 1 and 2, the inlet 114 and / or the outlet 116 may each include a plurality of openings. As illustrated, the openings of the outlet 116 may be formed between adjacent struts 118 of the plurality of struts 118 of the impeller housing 102. In other embodiments, the inlet 114 and / or the outlet 116 may each include a single opening. As shown in FIGS. 1 and 2, the inlet 114 may be formed at an end of the impeller housing 102 and adjacent to a distal support 120 coupled to the impeller housing 102. As shown in FIGS. 1 and 2, the outlet 116 may be formed on a side of the impeller housing 102. In other embodiments, the inlet 114 and / or the outlet 116 may be formed at other portions of the impeller housing 102. In some embodiments, the impeller housing 102 may be coupled to a distally extending cannula (not shown), which may receive blood and deliver it to the inlet 114.

[0035] Continuing to refer to FIGS. 1 and 2, motor housing 104 houses motor 122, which is configured to rotationally drive impeller 110 with respect to impeller housing 102. In the illustrated embodiment, motor 122 rotates drive shaft 124 coupled to drive magnet 126 (e.g., samarium cobalt magnet). Rotation of drive magnet 126 causes rotation of driven magnet 128 (e.g., samarium cobalt magnet) connected to impeller assembly 106. More specifically, impeller 110 rotates with driven magnet 128. In other embodiments, motor 122 may be coupled to impeller assembly 106 via other components.

[0036] In some embodiments, a controller (not shown) may be operably coupled to motor 122 and configured to control motor 122. In some embodiments, the controller may be disposed within motor housing 104. In other embodiments, the controller may be disposed outside of motor housing 104 (e.g., within a catheter handle, a separate housing, etc.). In some embodiments, the controller may include a plurality of components, one or more of which may be disposed within motor housing 104. In some embodiments, the controller may be one or more field programmable gate arrays (FPGAs), one or more programmable logic devices (PLDs), one or more complex PLDs (CPLDs), one or more custom application specific integrated circuits (ASICs), one or more dedicated processors (e.g., microprocessors), one or more central processing units (CPUs), software, hardware, firmware, or any combination of these and / or other components, may include them, or may be included in them. Although the controller is referred to herein in the singular, the controller may be implemented in multiple instances, may be distributed across multiple computing devices, may be instantiated within multiple virtual machines, and / or the like. In other embodiments, motor 122 may be controlled in other ways.

[0037] Referring further to FIGS. 1 and 2, blood pump 100 includes various components and features that provide reduced device-induced hemolysis as compared to conventional devices. More specifically, blood pump 100 includes an impeller housing 102 Fixed to and a defined bearing shaft 130 (also referred to herein interchangeably as simply a "shaft", e.g., a pin or rod made of stainless steel, ceramic, etc.). More specifically, shaft 130 is fixedly coupled to proximal hub 132 of impeller housing 102 and inner sleeve 134 (e.g., a silicone sleeve) of distal support 120. Bearing shaft 130 rotatably supports impeller assembly 106 and reduces or eliminates impeller vibrations and other undesirable impeller rotational dynamics that can cause relatively high shear and hemolysis in conventional blood pumps.

[0038] Since bearing shaft 130 need not radially capture impeller assembly 106, the use of relatively simple proximal and distal bearings for rotatably coupling impeller assembly 106 to impeller housing 102 and distal support 120 is possible. More specifically, blood pump 100 may include one or more proximal thrust bearings and one or more distal thrust bearings. In some embodiments, as shown, blood pump 100 includes a first proximal thrust bearing 136 that abuts and engages proximal hub 132 of impeller housing 102, and a second proximal thrust bearing 138 that abuts and engages first proximal thrust bearing 136, driven magnet 128, and inner tube 108. In some embodiments, as shown, blood pump 100 includes a first distal thrust bearing 140 that abuts and engages impeller 110 and inner tube 108, and a second distal thrust bearing 142 that abuts and engages first distal thrust bearing 140 and distal support 120 (more specifically, inner sleeve 134 of distal support 120).

[0039] The thrust bearings 136, 138, 140, and 142 can take various specific forms and can be made of various materials. For example, the first proximal thrust bearing 136, the second proximal thrust bearing 138, the first distal thrust bearing 140, and / or the second distal thrust bearing 142 can be flat bearings. As another example, the first proximal thrust bearing 136 and the second proximal thrust bearing 138 can be made of a relatively hard material (i.e., the bearings 136 and 138 can have a "hard-on-hard" arrangement). As another example, one of the first proximal thrust bearing 136 and the second proximal thrust bearing 138 can be made of a relatively hard material and the other can be made of a relatively soft material (i.e., the bearings 136 and 138 can have a "hard-on-soft" arrangement). As another example, the first distal thrust bearing 140 and the second distal thrust bearing 142 can be made of a relatively hard material. As another example, one of the first distal thrust bearing 140 and the second distal thrust bearing 142 can be made of a relatively hard material and the other can be made of a relatively soft material. As another example, the first proximal thrust bearing 136, the second proximal thrust bearing 138, the first distal thrust bearing 140, and / or the second distal thrust bearing 142 can be made of one or more ceramics such as silicon nitride or can be made of one or more gemstone materials such as sapphire.

[0040] Bearings 136, 138, 140, and 142 can provide one or more advantages over those of conventional blood pumps. For example, proximal bearings 136 and 138 can reduce or eliminate the gap on the proximal side of driven magnet 128, and distal bearings 140 and 142 can reduce or eliminate the gap on the distal side of impeller assembly 106. As a result, bearings 136, 138, 140, and 142 can reduce or eliminate potential thrombus formation at those locations that can lead to early pump failure. As another example, bearings 136, 138, 140, and 142 have a relatively large contact area, thereby reducing wear. As another example, proximal bearings 136 and 138 are relatively thin in the axial direction, enabling a relatively short distance to be provided between drive magnet 126 and driven magnet 128, and as a result, relatively high torque transmission is provided to impeller assembly 106. As yet another example, in contrast to conventional blood pumps, radial capture of impeller assembly 106 is provided by bearing shaft 130, so that no compressive load needs to be applied to impeller assembly 106 to ensure that bearings 136, 138, 140, and 142 remain seated during pump operation. The absence of this compressive load reduces friction and wear.

[0041] In some embodiments, blood pump 100 also includes further advantages compared to conventional blood pumps. For example, bearing shaft 130 is reinforced along its entire length by impeller 110, bearings 136, 138, 140, and 142, driven magnet 128, distal support 120, and impeller housing 102. These components reduce the stress on bearing shaft 130 and increase the overall strength of blood pump 100.

[0042] In some embodiments, the inner sleeve 134 functions as a compression spring to apply a thrust force to the bearings 136, 138, 140, and 142. In these embodiments, the second distal thrust bearing 142 may be axially slidable within the distal support 120. In other embodiments, the blood pump 100 does not include the inner sleeve 134.

[0043] FIG. 3 shows a flow diagram of an exemplary method 200 of manufacturing a blood pump, according to an embodiment of the subject matter disclosed herein, and FIGS. 4-6 show intermediate assemblies related to method 200. Method 200 describes the features of blood pump 100, but it is understood that any of the blood pumps contemplated herein may be used in a similar manner. At step 202, as also shown in FIG. 4, the method begins by preparing a first housing assembly 144. More specifically, preparing the first housing assembly 144 involves the shaft 130 being the impeller housing 102 Fixed toAs determined, it includes coupling the bearing shaft 130 to the impeller housing 102. As shown, the shaft 130 can be received in the through opening 146 of the proximal hub 132 of the impeller housing 102. In some embodiments, the bearing shaft 130 is welded or adhesively bonded within the proximal hub 132 of the impeller housing 102. Also, as shown in FIG. 4, preparing the first housing assembly 144 includes sliding the first proximal thrust bearing 136 onto the bearing shaft 130 and abutting it against the proximal hub 132 of the impeller housing 102. In some embodiments, the first proximal thrust bearing 136 is adhesively bonded to the proximal hub 132 of the impeller housing 102. Next, or simultaneously, in step 204, as shown in FIG. 5, the method includes preparing the impeller assembly 106. More specifically, preparing the impeller assembly 106 includes coupling the impeller 110, the driven magnet 128, the second proximal thrust bearing 138, and the first distal thrust bearing 140 to the inner tube 108 such that these components are rotatably fixed relative to each other. In some embodiments, the impeller 110 is overmolded onto the inner tube 108. In some embodiments, the driven magnet 128 is slid onto the proximal end of the inner tube 108 and adhesively bonded to the proximal end of the impeller 110. In some embodiments, the second proximal thrust bearing 138 is slid onto the inner tube 108 and adhesively bonded to the proximal end of the driven magnet 128. In some embodiments, the first distal thrust bearing 140 is slid onto the distal end of the inner tube 108 and adhesively bonded to the distal end of the impeller 110. Next, or simultaneously, in step 206, as shown in FIG. 6, the method includes preparing the second housing assembly 148. More specifically, preparing the second housing assembly 148 includes coupling the sleeve 134 and the second distal thrust bearing 142 to the distal support 120 such that these components are rotatably fixed relative to each other.In some embodiments, the sleeve 134 is inserted into the blind opening 150 of the distal support portion 120, and the second distal thrust bearing 142 abuts against the proximal end of the sleeve 134 and is adhesively bonded to the distal support portion 120.

[0044] Continuing to refer to FIG. 3 and further referring generally to FIGS. 4-6, the method continues in step 208 by coupling the impeller assembly 106 (FIG. 5) to the first housing assembly 144 (FIG. 4). More specifically, coupling the impeller assembly 106 to the first housing assembly 144 includes sliding the inner tube 108 along the bearing shaft 130 such that the second proximal thrust bearing 138 abuts loosely (i.e., without applying a load between the bearings) against the first proximal thrust bearing 136 and the impeller assembly 106 is rotatable relative to the first housing assembly 144. In some embodiments, coupling the impeller assembly 106 to the first housing assembly 144 further includes providing a lubricant between the inner tube 108 and the bearing shaft 130. Next, the method continues in step 210 by coupling the second housing assembly 148 (FIG. 6) to the impeller assembly 106 and the first housing assembly 144. More specifically, coupling the second housing assembly 148 to the impeller assembly 106 and the first housing assembly 144 includes inserting the bearing shaft 130 into the sleeve 134 and the distal support 120 such that the first distal thrust bearing 140 abuts loosely (i.e., without applying a load between the bearings) against the second distal thrust bearing 142. In some embodiments, coupling the second housing assembly 148 to the impeller assembly 106 and the first housing assembly 144 includes welding or adhesively bonding the sleeve 134 of the distal support 120 to the bearing shaft 130. In some embodiments, coupling the second housing assembly 148 to the impeller assembly 106 and the first housing assembly 144 includes welding or adhesively bonding one or more radially extending arms 152 of the distal support 120 to the impeller housing 102. The method ends in step 212 by operably coupling the impeller assembly 106 to the motor 122 (FIGS. 1 and 2) and coupling the impeller housing 102 to the motor housing 104 (FIGS. 1 and 2).In some embodiments, operably coupling the impeller assembly 106 to the motor 122 includes magnetically coupling the driven magnet 128 to the drive magnet 126 (Figs. 1 and 2). In some embodiments, coupling the impeller housing 102 to the motor housing 104 includes welding or adhesively bonding the impeller housing 102 to the motor housing 104.

[0045] FIG. 7 shows a partial cross-sectional view of another exemplary mechanical circulatory assist device or blood pump 300 according to an embodiment of the subject matter disclosed herein. The blood pump 300 is generally similar to the blood pump 100 described above. That is, the blood pump 300 includes an impeller housing 302 fixedly coupled to a bearing shaft 304. The bearing shaft 304 rotatably supports an impeller assembly 308 via a thrust bearing 306. The impeller assembly 308 is rotationally driven by a motor 310, and the motor 310 is mounted within a motor housing 312 coupled to the impeller housing 302. Also, the impeller housing 302 includes an inlet 314 and an outlet 316 that allow blood flow through the blood pump 300. However, unlike the blood pump 100 described above, the impeller housing 302 includes a proximal impeller housing portion 318 and a distal impeller housing portion 320 that are completely spaced apart, thereby forming an outlet 316 therebetween. In other words, the proximal impeller housing portion 318 and the distal impeller housing portion 320 are only indirectly coupled via the bearing shaft 304, whereby the proximal impeller housing portion 318 and the distal impeller housing portion 320 form an outlet 316 therebetween. In yet other words, the impeller housing 302 is not provided with a strut (for comparison, see, e.g., strut 118 of the blood pump 100) that couples the proximal impeller housing portion 318 and the distal impeller housing portion 320. As a result, the shear caused by the strut is eliminated and hemolysis is reduced.

[0046] FIG. 8 shows a partial cross-sectional view of another exemplary mechanical circulatory assist device or blood pump 400 according to an embodiment of the subject matter disclosed herein. Blood pump 400 is generally similar to blood pump 100 described above. That is, blood pump 400 includes an impeller housing 402 fixedly coupled to a bearing shaft 404. Bearing shaft 404 rotatably supports an impeller assembly (inner tube 408 of the impeller assembly is shown) via a bearing (one bearing 406 is shown). The impeller assembly is rotationally driven by a motor 410 via drive magnet 412 and driven magnet 414, and motor 410 is coupled to impeller housing 402. Additionally, unlike blood pump 100 described above, impeller housing 402 holds a protector 416, which may also be referred to as a proximal seal. As shown, protector 416 can be disposed both radially outward and distal to driven magnet 414. Thus, protector 416 can prevent blood from contacting driven magnet 414, thereby preventing corrosion and / or other wear. In some embodiments, protector 416 can be configured to maintain a volume of protective fluid in contact with driven magnet 414. The protective fluid can be, for example, a hydrophobic lubricant. The protective fluid can be any type of hydrophobic lubricant suitable for use in a blood pump. For example, the protective fluid can be a modified silicone lubricant such as modified polydimethylsiloxane (PDMS). In other embodiments, the protective fluid can be an oil-based lubricant, synthetic oil, carbon-based lubricant, and / or the like. In some embodiments, protector 416 can rotate with the impeller assembly and driven magnet 414 relative to impeller housing 402. In some embodiments, protector 416 can be fixed relative to impeller housing 402.

[0047] Generally, the blood pump 300 can be manufactured according to the method 200, except that the step of preparing the second housing assembly (step 206) can include coupling the distal support portion 322 to the distal impeller housing portion 320, for example, via welding or adhesive bonding. The second housing assembly can then be coupled to the first housing assembly and the impeller assembly.

[0048] FIG. 9 shows a partial cross-sectional view of another exemplary mechanical circulatory assist device or blood pump 500 according to an embodiment of the subject matter disclosed herein. The blood pump 500 is generally similar to the blood pump 100 described above. That is, the blood pump 500 includes an impeller housing 502 fixedly coupled to a bearing shaft 504. The bearing shaft 504 rotatably supports an impeller assembly 510 via a proximal thrust bearing 506 and a first distal thrust bearing 508. The impeller assembly 510 is rotationally driven by a motor 512, and the motor 512 is mounted within a motor housing 514 coupled to the impeller housing 502. Also, the impeller housing 502 includes an inlet 516 and an outlet 518 that allow blood flow through the blood pump 500. However, unlike the blood pump 100 described above, the blood pump 500 does not have a support such as the distal support portion 120 (shown elsewhere) of the pump 100 that couples the shaft 504 to the impeller housing 502 and is disposed distally with respect to the impeller assembly 510. To suppress the axial movement of the impeller assembly 510 with respect to the bearing shaft 504, the bearing shaft 504 holds a distal keeper 520 in the vicinity of the inlet 516. The keeper 520 can be, for example, a snap ring held by the bearing shaft 504 as shown. Alternatively, the keeper 520 can take other forms. In some embodiments, as shown, the keeper 520 abuts and engages the first distal thrust bearing 508 and thereby can function as a second distal thrust bearing.

[0049] Generally, the blood pump 500 can be manufactured in accordance with method 200, except that the step of providing the second housing assembly (step 206) is omitted and the step of coupling the second housing assembly to the impeller assembly and the first housing assembly (step 210) is replaced by coupling the keeper 218 to the impeller assembly and the first housing assembly via, for example, snap fitting, welding, or adhesive bonding.

[0050] Without departing from the scope of the present invention, various modifications and additions can be made to the exemplary embodiments described. For example, although the above-described embodiments refer to specific features, the scope of the present invention includes embodiments having different combinations of features and embodiments that do not include all of the described features. Accordingly, the scope of the present invention is intended to embrace all such alternatives, modifications, and variations that are included within the claims, together with all of their equivalents.

Claims

1. A percutaneous circulatory assist device, comprising a housing, a shaft fixed to the housing, an impeller disposed within the housing and rotatably supported by the shaft, the impeller being configured to rotate relative to the shaft and the housing so that blood flows through the housing, and a keeper coupled to the shaft on the distal side of the impeller, the keeper suppressing axial movement of the impeller relative to the shaft. A percutaneous circulatory assist device comprising the above components.

2. The percutaneous circulatory assist device according to claim 1, wherein the keeper functions as a thrust bearing.

3. The percutaneous circulatory assist device according to claim 1 or 2, wherein the shaft is coupled to the housing and no support portion is provided distally of the impeller.

4. The percutaneous circulatory assist device according to claim 1 or 2, further comprising a motor operable to rotationally drive the impeller relative to the shaft and the housing so that blood flows through the housing.

5. The percutaneous circulatory assist device according to claim 1 or 2, further comprising a thrust bearing coupling the impeller to the housing.

6. The percutaneous circulatory assist device according to claim 5, wherein the thrust bearing is a proximal thrust bearing, and the percutaneous circulatory assist device further comprises a distal thrust bearing coupling the impeller to the housing.

7. The percutaneous circulatory assist device according to claim 1 or 2, further comprising an impeller assembly including the impeller and an inner tube rotatably supported by the shaft, the impeller being fixed to the inner tube.

8. a motor, a drive magnet operably coupled to the motor, a driven magnet operably coupled to the drive magnet, the inner tube and the impeller being fixed to the driven magnet, wherein the motor is operable to rotationally drive the impeller via the drive magnet and the driven magnet so that blood flows through the housing. The percutaneous circulatory assist device according to claim 7.

9. A percutaneous circulatory assist device, a motor, a housing, a shaft fixed to the housing, a keeper coupled to the shaft, an impeller disposed within the housing, rotatably supported by the shaft, and axially constrained with respect to the shaft by the keeper, The motor is operable to rotationally drive the impeller with respect to the housing to cause blood to flow through the housing, a percutaneous circulatory assist device.

10. The percutaneous circulatory assist device according to claim 9, wherein the keeper functions as a thrust bearing.

11. The percutaneous circulatory assist device according to claim 9 or 10, wherein the keeper is disposed distally with respect to the impeller.

12. The percutaneous circulatory assist device according to claim 9 or 10, wherein the percutaneous circulatory assist device is provided with a support portion that couples the shaft to the housing and is disposed distally with respect to the impeller.

13. The percutaneous circulatory assist device according to claim 9 or 10, further comprising a thrust bearing coupled to the impeller.

14. The percutaneous circulatory assist device according to claim 9 or 10, further comprising an impeller assembly, the impeller assembly including the impeller and an inner tube rotatably supported by the shaft, the impeller being fixed to the inner tube.

15. a drive magnet operably coupled to the motor, a driven magnet operably coupled to the drive magnet, the inner tube and the impeller being fixed to the driven magnet, the driven magnet, The motor is operable to rotationally drive the impeller through the drive magnet and the driven magnet to cause blood to flow through the housing, the percutaneous circulatory assist device according to claim 14.

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