Seals for mechanical circulatory assist devices

Abstract

The present disclosure is generally directed to mechanical cardiovascular assist systems used in the medical field to assist in the movement of blood. In particular, the present disclosure is directed to a mechanical cardiovascular assist system in which an impeller is connected to a motor via a rotating drive shaft, the motor is contained within a motor compartment, the rotating drive shaft extends from the motor compartment, and a mechanical seal, e.g., a rotating shaft lip seal, prevents blood from entering the motor compartment. The seal may have an inverted radial shaft seal, may have two opposing radial shaft seals, and / or may have one or more elastomeric disks, among other features.

Description

[Background technology]

[0001] The present disclosure is generally directed to devices deliverable to a patient's circulatory system, such as the left ventricle and aorta, to provide mechanical circulatory support. The present disclosure is more particularly directed to a seal for a mechanical circulatory support device. Summary of the Invention

[0002] The present disclosure relates to a seal for a mechanical circulatory assist system. Such a system may have an impeller rotated by a motor, and the seal reduces or prevents blood flow from entering the compartment in which the motor is located. Each of the embodiments disclosed herein has several aspects, no single one of which is solely responsible for the desirable attributes of the present disclosure. Without limiting the scope of the present disclosure, its more prominent features will now be briefly discussed. After considering this discussion, and particularly after reading the section entitled "Description of the Preferred Embodiments," one will appreciate how the features of the embodiments described herein provide advantages over existing systems, devices, and methods of mechanical circulatory assist systems.

[0003] The following disclosure describes non-limiting examples of some embodiments of a seal for a mechanical circulatory assist device. For example, other embodiments of the disclosed systems and methods may or may not include features described herein. Furthermore, the disclosed advantages and benefits may only apply to certain embodiments and should not be used to limit the present disclosure.

[0004] A first aspect of the present disclosure is a seal for a heart pump, the seal comprising: a distal radial shaft seal configured to surround a shaft of the heart pump, the distal radial shaft seal having a flat side facing distally and an open side facing proximally; and a proximal radial shaft seal configured to surround the shaft and be located proximal to the distal radial shaft seal, the proximal radial shaft seal being located farther from the impeller of the pump than the distal radial shaft seal, with the flat side facing proximally and the open side facing distally.

[0005] A second embodiment is the seal of embodiment 1, wherein the distal radial shaft seal comprises a radially inner lip configured to contact the shaft and extend proximally from the flat side of the distal radial shaft seal.

[0006] A third aspect is the seal of aspect 1 or 2, further comprising a distal spring located at least partially within the open side of the distal radial shaft seal and configured to urge a radially inner lip of the distal radial shaft seal radially inwardly onto the shaft.

[0007] A fourth aspect is the seal of any of aspects 1-3, further comprising a proximal spring located at least partially within the open side of the proximal radial shaft seal and configured to urge a radially inner lip of the proximal radial shaft seal radially inwardly onto the shaft.

[0008] A fifth embodiment is the seal of any of embodiments 1-4, further comprising one or more disks comprising a central opening having an inner diameter configured to be smaller than an outer diameter of the shaft.

[0009] A sixth embodiment is the seal of embodiment 5, wherein a radially inner edge of the central opening of each of the disks is configured to wear in response to rotation of the shaft.

[0010] A seventh aspect is the seal of any of aspects 1-6, further comprising grease located between the distal radial shaft seal and the intermediate disc, and between the intermediate disc and the proximal radial shaft seal.

[0011] An eighth embodiment is the seal of any of embodiments 1-7, wherein the distal radial shaft seal and the proximal radial shaft seal each have a radially outer lip configured to contact an inside of the housing.

[0012] A ninth embodiment is the seal of any of embodiments 1-1, wherein the seal is configured to be assembled with a heart pump and delivered to the heart via a catheter.

[0013] A tenth aspect is a seal according to any of aspects 1-8, further comprising a housing having a distal end wall and a cylindrical side wall extending proximally from the distal end wall, the distal end wall having a distal side configured to contact the blood flow, and a central opening configured to receive the shaft therethrough, the distal radial shaft seal configured to be located at least partially within the housing, proximal to the distal end wall.

[0014] Another aspect is a heart pump (22) comprising a motor (145) having a rotor, an impeller (72) for providing blood flow, a drive shaft (140) connected to the rotor and the impeller, and a sealing element (156) disposed between the motor and the impeller, the sealing element (156) including a central aperture for receiving the drive shaft (140) in sliding sealing contact such that the motor (145) is sealed from the blood flow.

[0015] Another aspect is a heart pump that uses a barrier fluid to prevent blood from entering the motor of the heart pump. Thus, the operating time of the heart pump can be extended. The corresponding heart pump comprises a housing, an impeller, a motor, a sealing element, and a barrier fluid. The housing has an interior and an opening to the interior. The impeller has at least one blade, and the impeller is positioned next to the opening. The motor is located inside the housing and has a shaft that passes through the opening and is coupled to the impeller to drive the impeller. The sealing element is located between the impeller and the motor housing and is designed to seal a gap between the impeller and the housing. The barrier fluid is located between the sealing element and the shaft, which are arranged and designed to prevent media from the environment surrounding the heart pump from entering the interior of the motor. The impeller is driven by the motor via the shaft. The sealing element can be ring-shaped. The sealing element can be attached to the impeller. This allows the sealing element to rotate with the impeller. Alternatively, the sealing element can be attached to the motor housing. Regardless of the mounting manner, the gap between the impeller and the motor housing can be sealed using a sealing element. The barrier fluid can also be located inside the motor. In this case, there is no need for an additional sealing element to prevent the barrier fluid from entering the interior through the opening. According to the design form, the sealing element can be designed as a contact seal or a contactless seal. Any suitable sealing form can therefore be used. Furthermore, the sealing element can be designed as a labyrinth seal and additionally or alternatively as a gap seal. Such seals are wear-free and have low friction. Furthermore, the heart pump can have a second sealing element. The second sealing element can be located at the opening and designed to seal the interior of the motor housing against the space between the motor housing and the impeller. The barrier fluid can be located in the gap. In this way, the barrier fluid can be prevented from entering the motor interior.Furthermore, the heart pump may have at least one bearing, which is designed to support the shaft inside the housing. Advantageously, the shaft may also be centered by the at least one bearing. The barrier fluid may be a biocompatible medium. This means that the barrier fluid will not adversely affect the patient in case of a heart pump leak. According to one design, the barrier fluid may consist of glucose and / or endogenous fats. This ensures optimal biocompatibility.

[0016] The foregoing and other features of the present disclosure will become more fully apparent from the following description and appended claims taken in conjunction with the accompanying drawings. The present disclosure will be described with further specificity and detail through the use of the accompanying drawings, with the understanding that these drawings depict only some embodiments according to the present disclosure and should not be considered as limiting its scope. In the following detailed description, reference will be made to the accompanying drawings, which form a part of this specification. In the drawings, like symbols typically identify like components unless the context dictates otherwise. The exemplary embodiments described in the detailed description, drawings, and claims are not intended to be limiting. Other embodiments may be utilized and other changes may be made without departing from the spirit or scope of the subject matter presented herein. It will be readily understood that aspects of the present disclosure, as generally described herein and illustrated in the drawings, can be arranged, substituted, combined, and designed in a wide variety of different configurations, all of which are expressly contemplated and made a part of this disclosure. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a cross-sectional view of the distal end of an embodiment of a catheter-assisted mechanical circulatory support (MCS) system positioned across the aortic valve. [Diagram 2] 1 shows a schematic representation of an embodiment of an MCS system inserted into the body via a femoral artery access path to the left ventricle. [Diagram 3]FIG. 1 is a side elevation view of an embodiment of an MCS system that may incorporate various features described herein. [Figure 4] FIG. 4 is the system of FIG. 3 with the introducer sheath removed, including the insertion tool and guidewire retraction loading aid. [Diagram 5] 1 illustrates an introducer kit having a sheath and a dilator that may be used with the various MCS systems and methods described herein. [Figure 6] 1 illustrates a positioning guidewire that may be used with the various MCS systems and methods described herein. [Figure 7] FIG. 2 is a perspective partial view of a distal pump region of the MCS system of FIG. 1. [Figure 8] FIG. 2 is a side elevational view of the distal region of the MCS system of FIG. 1 showing the guidewire pathway and guidewire pullback loading aid in place. [Figure 9A] FIG. 2 is a side view of an embodiment of an MCS device that may be used in the MCS system of FIG. [Figure 9B] FIG. 9B is a partial cross-sectional view of the MCS device of FIG. 9A showing an embodiment of a seal. [Figure 10] FIG. 13 is a partial cross-sectional view of another embodiment of an MCS device having a distally facing lip seal and a distal protective disk. [Figure 11] FIG. 13 is a partial cross-sectional view of another embodiment of an MCS device having a distally facing lip seal, a distal protective disk, and a proximal disk. [Figure 12] FIG. 13 is a partial cross-sectional view of another embodiment of an MCS device having a proximally facing lip seal and a proximal disk. [Figure 13A] FIG. 13 is a partial cross-sectional view of another embodiment of an MCS device having a distally facing lip seal, a distal protective disk having a contoured surface, and an impeller having a matching contour. [Figure 13B] FIG. 13 is a partial cross-sectional view of another embodiment of an MCS device having a distally facing lip seal, a distal protective disk having a contoured surface, and an impeller having a non-matching contour (e.g., flat). [Figure 14A] FIG. 13 is a partial cross-sectional view of another embodiment of an MCS device having two lip seals facing each other, optionally with one garter spring or two garter springs. [Figure 14B] FIG. 13 is a partial cross-sectional view of another embodiment of an MCS device having two lip seals facing each other, showing an optional leading edge on the distal lip seal. [Figure 14C] FIG. 13 is a partial cross-sectional view of another embodiment of an MCS device having two lip seals facing each other, showing an optional leading edge on the distal protective disk. [Figure 15] FIG. 13 is a partial cross-sectional view of another embodiment of an MCS device having a pressure balancing lubricant reservoir. [Figure 16A] FIG. 13 is a partial cross-sectional view of another embodiment of an MCS device having two facing lip seals, a distal disk, a middle disk, and a proximal disk contained within a seal housing. [Figure 16B] FIG. 16B is an isometric exploded view, partially cut away, of the seal component of FIG. 16A. [Figure 16C] FIG. 16B is a cross-sectional view of the seal components of FIG. 16A shown separately as subassemblies for ease of manufacture and assembly. [Figure 16D] 13 is a side cross-sectional view of another embodiment of a seal assembly, wherein the proximal disc has enlarged radial and axial contact surfaces. FIG. [Figure 16E] FIG. 13 is a perspective cross-sectional view of an embodiment of a seal assembly and impeller, wherein the seal assembly has a distally tapered distal seal can. [Figure 16F] 1A-1D show various views of the seal assembly, impeller, and flow channel, with the seal assembly having a distally tapered distal seal receptacle and an outlet strut support member, shown in a transparent housing for clarity. [Figure 16G] 1A-1D show various views of the seal assembly, impeller, and flow channel, with the seal assembly having a distally tapered distal seal receptacle and an outlet strut support member, shown in a transparent housing for clarity. [Figure 17A] FIG. 1 illustrates an isometric view of an embodiment of an impeller having a smooth base surface. [Figure 17B] FIG. 17B is an isometric view of an embodiment of an impeller having proximal vanes, as opposed to the impeller of FIG. 17A, that may optionally be used with any MCS device or seal described herein, such as those shown in FIGS. 9B, 10, 11, 12, 14A, 14B, 14C, 15, 16A, 16B, or 16C. [Figure 17C] FIG. 17B is an isometric view of an embodiment of an impeller having proximal vanes, as opposed to the impeller of FIG. 17A, that may optionally be used with any MCS device or seal described herein, such as those shown in FIGS. 9B, 10, 11, 12, 14A, 14B, 14C, 15, 16A, 16B, or 16C. [Figure 18A] FIG. 1 is a cross-sectional view of an embodiment of an impeller secured to a drive shaft via an impeller base plate that may be used in the various MCS systems described herein. [Figure 18B] FIG. 13 is a cross-sectional view of an embodiment of an impeller directly mounted to a drive shaft that may be used in the various MCS systems described herein. [Figure 18C] FIG. 1 is an isometric cutaway view of an embodiment of an impeller secured to a drive shaft with a locking key that may be used in the various MCS systems described herein. [Figure 19] FIG. 2 is a cross-sectional view of another embodiment of an MCS device having an axial lip seal and a radial face lip seal that may be used in the various MCS systems described herein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] The disclosure herein relates to a mechanical circulatory assist (MCS) system and device having an impeller connected to a drive shaft driven by a motor, where blood is prevented from entering the motor by one or more seals and / or other barrier mechanisms. The following detailed description is directed to certain specific embodiments. In this description, reference is made to the drawings, and for clarity, like parts or steps may be designated with like numerals throughout. References herein to "one embodiment," "an embodiment," or "in some embodiments" mean that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of the invention. The appearance of the phrases "one embodiment," "embodiment," or "in some embodiments" in various places in this specification do not necessarily all refer to the same embodiment, nor are separate or alternative embodiments necessarily mutually exclusive with other embodiments. Furthermore, various features are described that may be exhibited by some embodiments and not by other embodiments. Similarly, various requirements are described that may be requirements in some embodiments and not in other embodiments. Reference will now be made in detail to the present embodiments of the invention, examples of which are illustrated in the accompanying drawings.

[0019] A. Mechanical Circulatory Support (MCS) System The sealing components described herein may be part of a mechanical circulatory support (MCS) device or MCS system 10, such as the system described below.

[0020] As shown in Figures 1 and 2, the MCS system 10 may include a temporary (typically about 6 hours or less, or about 3 hours or less, 4 hours or less, 5 hours or less, 7 hours or less, 8 hours or less, or 9 hours or less) left ventricular assist pump 22 for use during various procedures, such as high-risk percutaneous coronary interventions (PCI) performed on elective or emergency hemodynamically stable patients with severe coronary artery disease and / or reduced left ventricular ejection fraction. The system 10 may be used when a cardiac team, including a cardiac surgeon, determines that high-risk PCI is an appropriate treatment option. The system 10 is positioned across the aortic valve, for example, via a single femoral artery access.

[0021] The MCS system 10 includes a low profile axial rotary blood pump mounted on a catheter, such as an 8 French (Fr) catheter 16, where 1 Fr equals 1 / 3 millimeter (mm). The pump may be referred to as an MCS pump or MCS device. When in place, the MCS pump is driven by an MCS controller 180 to provide partial left ventricular assist of up to about 4.0 liters / minute at about 60 mmHg. Purging of the system is not required because the motor is sealed. Also, the need for purging may be avoided due to an improved bearing design. By "purging" we mean that the system does not require glucose or other types of liquid purging to be repeatedly introduced into the system through tubing to prevent contamination of the motor with blood. Thus, the MCS system 10 avoids the complexities associated with systems that require purging, resulting in a simpler and less expensive device that is easier to use. The system may be visualized under fluoroscopy, eliminating the need for positioning using sensors.

[0022] The system may further include an expandable sheath 12. The sheath 12 may allow for an initial access size of 8-10 Fr for ease of insertion and access, may be expandable to allow introduction of 14 Fr and 18 Fr pump devices, and may revert to the narrower diameter of approximately an 8 Fr catheter once the pump has passed. This feature may allow passage of the cardiac pump through the vasculature while minimizing shear forces within the vessels, advantageously reducing the risk of bleeding and healing complications. Distension or stretching of the arteriotomy may be performed by radial stretching with minimal shear to harm the vessels. Access may be achieved via a transfemoral, transaxillary, transaortic, or transapical approach.

[0023] FIG. 1 further illustrates the distal end of the MCS system 10 with the pump 22 mounted on the tip of the 8Fr catheter 16. As used herein, "distal" and "proximal" refer to directions further from and closer to the body, respectively, along the MCS system 10 in use, as further illustrated by way of example in FIGS. 3 and 9B. The inlet tube portion 70 of the device extends across the aortic valve 202. The impeller is located in the outflow section 68 of the inlet tube, drawing blood from the left ventricle 203 through the inlet tube 70 and expelling blood from the outflow section 68 into the ascending aorta 204. The motor 145 is mounted proximal to the impeller, which may be just proximal to the impeller, in a sealed housing, eliminating the need to flush the motor before or during use. This configuration provides hemodynamic support during high-risk PCI, time and safety for complete revascularization with a minimally invasive approach (not open surgery).

[0024] The system is designed to eliminate the need for motor flushing. The system also provides improved flow performance up to 4.0 l / min at 60 mmHg and safe hemolysis with a computational fluid dynamics (CFD) optimized impeller that minimizes shear stress. The seals and other features described herein contribute to these and other advantages.

[0025] The MCS device 10 actively relieves the left ventricular load by pumping blood from the ventricle into the ascending aorta and into the systemic circulation (shown in Figures 1 and 2). When in place, the MCS device is driven by a complementary MCS controller and can provide partial left ventricular assist of 0.4 liters per minute (l / min) up to 4.0 l / min.

[0026] In general, the overall MCS system 10 may include a series of associated subsystems and accessories, including one or more of the following: • The MCS device 10 may include a pump, shaft, proximal hub, insertion tool, proximal cable, infection shield, and guidewire accessory. The MCS device may be provided sterile. • The MCS shaft may contain an electrical cable and a guidewire lumen for over-the-wire insertion. • The proximal hub may contain a guidewire exit port with a valve to maintain hemostasis and connect the MCS shaft to the proximal cable that connects the MCS device to the MCS controller. ● The proximal cable may be 3.5 meters (m) (approximately 177 inches (in)) long and may extend from the sterile field to the non-sterile field where the MCS controller is located. • The MCS insertion tool may be part of the MCS device 10 and may facilitate insertion of the pump into the introducer sheath and protect the inlet tubing and valves from potential damage or interference as they pass through the introducer sheath. • A peel-away guidewire aid may be pre-loaded onto the MCS device 10 to facilitate insertion of a 0.018 inch positioning guidewire into the pump and into the MCS shaft. A 3 meter long 0.018 inch positioning guidewire may be used with a soft coiled preformed tip for atraumatic wire positioning into the left ventricle. The guidewire may be provided sterile. ● A 14Fr introducer sheath with a usable length of 275mm can be used to maintain access into the femoral artery and achieve hemostasis for 0.035 inch guidewires, diagnostic catheters, 0.018 inch positioning guidewires, and insertion tools. The introducer sheath housing can be designed to accommodate the MCS insertion tool. The introducer sheath can be provided sterile. The introducer dilator may be compatible with the introducer sheath and may facilitate atraumatic insertion of the introducer sheath into the femoral artery. The introducer dilator may be provided sterile. ● An MCS controller may be used that drives and / or operates the MCS device, monitors its performance and status, and provides error and status information. The powered controller may be designed to support at least about 12 hours of continuous operation and may include a basic interface to indicate and adjust the level of assistance provided to the patient. Additionally, the controller may provide optical and audible alarm notifications if the system detects an error during operation. The MCS controller may be provided in a non-sterile condition and may be contained within an enclosure designed to be cleaned and reused outside of the sterile field. The controller enclosure may include a socket into which an extension cable may be plugged.

[0027] Referring to FIG. 3, an overall MCS system 10 according to one aspect of the present development is illustrated, the subcomponents of which are described in more detail below. The system 10 includes an introducer sheath 12 having a proximal introducer hub 14 with a central lumen for axially movably receiving an MCS shaft 16. The MCS shaft 16 extends between a proximal hub 18 and a distal end 20. The hub 18 may be provided with an integrated microcontroller or memory storage for device identification and tracking of run time, which may be used to prevent overuse to avoid excessive wear or other technical malfunctions. The microcontroller or memory storage may disable the device, for example, to prevent use of a used device. The microcontroller or memory storage may communicate with a controller that may display information about the device or messages about its use. An atraumatic cannula tip with radiopaque material allows the implantation / interpretation to be visible under fluoroscopy.

[0028] The pump 22 is supported by a distal region of the MCS shaft 16. The system 10 is provided with at least one central lumen for axially movably receiving a guidewire 24. The proximal hub 18 is additionally provided with an infection shield 26. A proximal cable 28 extends between the proximal hub 18 and a connector 30 for releasable connection to a control system, typically outside the sterile field, to drive the pump 22. The pump 22 may include any of the seal embodiments described herein, such as those described and illustrated in FIGS. 9B-16C, 18A, 18B, or 19.

[0029] 4, the system 10 additionally includes an insertion tool 32 having an elongated tubular body 36 having a length within the range of about 85 mm to about 160 mm (e.g., about 114 mm) and an inner diameter within the range of about 4.5 mm to about 6.5 mm (e.g., about 5.55 mm) extending distally from a proximal hub 34. The tubular body 36 includes a central lumen adapted to axially movably receive the MCS shaft 16 and the pump 22 therethrough, and the tubular body 36 includes sufficient crush resistance to maintain patency when passed through a hemostatic valve of the introducer sheath. As shown in FIG. 4, the pump 22 may be positioned within the tubular body 36, such as to facilitate passage of the pump 22 through a hemostatic valve on the proximal end of the introducer hub 14. A marker 37 (FIG. 7) is provided on the shaft 16 spaced proximally from the distal tip 64 so that the clinician can tell that the pump is within the tubular body 36 as long as the marker 37 is visible on the proximal side of the hub 34.

[0030] The hub 34 may be provided with a first engagement structure 39 for engaging a complementary second engagement structure on the introducer sheath to lock the insertion tool within the introducer sheath. The hub 34 may also be provided with a locking mechanism 41 for clamping onto the shaft 16 to prevent the shaft 16 from sliding proximally or distally through the insertion tool when the MCS device is positioned at a desired location within the heart. The hub 34 may additionally be provided with a hemostatic valve to seal around the shaft 16 and to accommodate the passage of a larger diameter MCS device, including a pump. In one commercial presentation of the system, the packaged MCS device is pre-positioned within the insertion tool and the guidewire aid is pre-loaded within the MCS device and shaft 16, as shown in FIG. 4.

[0031] Guidewire aid 38 (also shown in FIG. 8 ) includes a proximal opening 90 at the distal end of inlet tube 70 configured to slidably and removably receive over distal tip 64 and / or struts defining a window in pump inlet 66. Guidewire guide tube 83 has a lumen therethrough and is positioned within proximal opening 90 and aligned to pass through guidewire port 76 in distal tip 64. The lumen of guidewire guide tube 83 communicates with a distal flared funnel-shaped opening 92 that increases in cross section distally. Guidewire aid 38 may be provided assembled on MCS pump 22 with guidewire guide tube 83 pre-loaded to pass along the guidewire path, for example, through port 76 into MCS pump 22, through a portion of the fluid path in inlet tube 70, out of MCS pump 22 through port 78, along the exterior of the MCS pump, and into shaft 16 through port 80. This aids the user in guiding the proximal end of the guidewire through the guidewire pathway and into the funnel 92 and into the guidewire lumen of the MCS shaft 16. A pull tab 94 may be provided on the guidewire aid 38 to facilitate grasping and removal of the guidewire aid, including the guidewire guide tube 83, after loading of the guidewire. The guidewire aid 38 may have longitudinal slits or tear lines, for example along the funnel 92, the proximal opening 90, and the guidewire guide tube 83, to facilitate removal of the guidewire aid 38 from the MCS pump 22 and guidewire 100.

[0032] 5 and 6, an introducer kit 110 may include a guidewire 100, an introducer sheath 112, a dilator 114, and / or a guidewire aid 38, for example, as described above. The guidewire 100 may include an elongated flexible body 101 extending between a proximal end 102 and a distal end 104. A distal zone of the body 101 may be pre-formed into a J-tip or pigtail to provide an atraumatic distal tip, as shown in FIG. 6. The proximal zone 106 is configured to facilitate threading through the MCS device and extends between the proximal end 102 and a transition section 108. The proximal zone 106 has an axial length in the range of about 100 mm to about 500 mm (e.g., about 300 mm).

[0033] The introducer kit 110 comprises a sheath 112 and a dilator 114. The sheath 112 comprises an elongated tubular body 116 extending between a proximal end 118 and a distal end 120. The tubular body 116 terminates proximally in a proximal hub 122. Optionally, the tubular body 116 is expandable or peelable. The proximal hub 122 includes a proximal end port 124 in communication with a central lumen extending the length of the tubular body 116 and exiting through a distal opening, the proximal end port 124 configured to axially and removably receive the elongated dilator 114. The proximal hub 122 is additionally provided with at least one and optionally two or more attachment mechanisms, such as a side port 126, an eye 128 to facilitate suturing to the patient, and at least one and optionally multiple hemostatic valves to provide a seal around various introduced components, such as a standard 0.035 inch guidewire, a 5 Fr or 6 Fr diagnostic catheter, a 0.018 inch positioning guidewire 100, and an insertion tool 32.

[0034] Further details of the distal pump region of the MCS system are shown in FIG. 7. A pump zone 60 extends between a bend relief 62 at the distal end of the shaft 16 and a distal tip 64. A pump inlet 66 is in fluid communication with a pump outlet 68 by a flow passage extending axially through an inlet tube 70. The pump inlet may be positioned around the transition between the inlet tube and the proximal end of the distal tip 64, and generally may be within about 5 cm or less or within 3 cm or less of the distal port 76. In some embodiments, the distal tip 64 is radiopaque. For example, the distal tip 64 may be made from a polymer containing a radio-opacifying agent, such as barium sulfate, bismuth, tungsten, iodine, etc. In some embodiments, the entire MCS device is radiopaque. In some embodiments, a radiopaque marker is positioned on the inlet tube between the pump outlet 68 and the guidewire port 78 to indicate the current position of the aortic valve. The inlet tube 70 may comprise a highly flexible slotted (e.g., laser cut) metal (e.g., Nitinol) tube with a polymer (e.g., polyurethane) tube layer to isolate the flow path. The inlet tube may have an axial length in the range of about 60 mm to about 100 mm, and in one implementation is about 67.5 mm. The outer diameter may typically be in the range of about 4 mm to about 5.4 mm, and in one implementation is about 4.66 mm. The connection between the inlet tube and the distal tip and to the motor may be fixed, such as by using laser welding, adhesives, threading, or other interference fit engagement structures, or may be by press fit.

[0035] The impeller 72 may be positioned in the flow path between the pump inlet 66 and the pump outlet 68. In the illustrated embodiment, the impeller 72 is positioned adjacent to the pump outlet 68. As discussed further below, the impeller 72 is driven to rotate by a motor contained within a motor housing 74 on a proximal side of the impeller 72.

[0036] The MCS device may be provided in either a rapid exchange or over the wire configuration. A first guidewire port 76 extends through the sidewall of the inlet tube 70 via a first guidewire lumen through the distal tip component 64 and at least a portion of the flow path in the inlet tube, and communicates with a second guidewire port 78 distal to the impeller 72. This may be used for rapid exchange with a guidewire extending proximally alongside the catheter from the second guidewire port 78.

[0037] The catheter may be provided in an over-the-wire configuration, where the guidewire extends proximally through the guidewire lumen the entire length of the catheter. However, in the over-the-wire embodiment shown in FIG. 7, the guidewire exits the catheter via a second guidewire port 78, extends proximally over the outside of the impeller and motor housing, and re-enters the catheter shaft 16 via a third guidewire port 80. See also FIG. 8. The third guidewire port 80 is located proximal to the motor, and in the illustrated embodiment, is located on the bend relief 62. The third guidewire port 80 is in communication with a guidewire lumen that extends proximally the entire length of the shaft 16 and exits at a proximal guidewire port supported by the proximal hub 18.

[0038] The pump may be provided assembled with a removable guidewire accessory 38 having a guidewire guide tube 83 that follows the intended path of the guidewire from a first guidewire port 76 proximally through the tip 64, through a second guidewire port 78 out the inlet tube, and into the catheter through a third guidewire port 80. In the illustrated implementation, the guidewire guide tube extends proximally within the catheter to a proximal end 81 and communicates with or extends within a guidewire lumen that extends to the proximal hub 18. The guidewire guide proximal end 81 may be positioned within about 5 mm or 10 mm of the distal end of the shaft 16, or may extend within the catheter shaft guidewire lumen by at least about 10 mm or 20 mm, such as within a range of about 10 mm to about 50 mm. The proximal end 102 of the guidewire may be inserted into the funnel 92, passed through the first (distal) guidewire port 76, and guided along the intended path by following the inside of the guidewire guide tube. The guidewire guide tube may then be removed and the guidewire left in place.

[0039] In one implementation, the distal end of the guidewire guide tube 83 is attached to a pull tab 94 of the guidewire aid 38 and is provided with an axially extending split line, such as a weakened line, a slotted line, or a perforated tearable line. Removal may be accomplished by grasping the pull tab 94 and pulling out the guidewire tube while splitting and peeling the guidewire tube along the split line, or the like. The inner surface of the guide tube 83 may be provided with a lubricious coating, such as polytetrafluoroethylene (PTFE).

[0040] FIG. 9A is a side view of one embodiment of an MCS device that may be used in the MCS system 10. FIG. 9B is a partial cross-sectional view of the region of the MCS device shown in FIG. 9A showing, among other features, an embodiment of a seal. With reference to FIGS. 9A and 9B, the impeller 72 is attached to a stiff motor drive shaft 140 that may be relatively short (e.g., in the range of 29 mm to 34 mm). Some of the features disclosed herein, such as the sealing element (159), may be adapted for use with a heart pump having a motor that is kept external to the body and connected to an impeller within the heart with a long flexible drive shaft that may have a length in the range of 1200 mm to 1500 mm. In the illustrated implementation, the drive shaft 140 extends distally into a proximally facing central lumen 142 within the impeller 72, such as through a proximal extension 154 on the impeller hub 146, and may be secured by press fit, laser welding, adhesive, or other joining techniques. The impeller 72 includes helical blades 178 extending radially outwardly and spaced at the maximum outer diameter of the helical blades 178 from the inner surface of the tubular impeller housing 82. The blades 178 may be spaced in a range of about 40 μm to about 120 μm. The impeller housing 82 may be a proximal extension of the inlet tube 70 on the proximal side of the slot 71 formed in the inlet tube 70, providing flexibility distal to the impeller. A tubular outer membrane 73 surrounds the inlet tube and seals the slot 71 while retaining the flexibility of the inlet tube. The pump outlet 68 is formed in a sidewall of the impeller housing, for example, axially aligned with a proximal portion of the impeller (e.g., the proximal 25% to 50% of the impeller).

[0041] The impeller 72 may comprise medical grade titanium. This allows for a computational fluid dynamics (CFD) optimized impeller design to minimize shear stress to reduce blood cell damage (hemolysis) and increase efficiency at non-constant ramps. This latter feature cannot be achieved with mold-based fabrication methods. Electropolishing of the surface reduces surface roughness to minimize its impact on hemolysis.

[0042] In some embodiments, the impeller hub 146 flares radially outward in the proximal direction to form an impeller base 150 that can direct blood flow out of the outlet 68. The proximal surface of the impeller base 150 is fixedly attached to an impeller base plate 152, which can be in the form of a radially outwardly extending flange fixedly attached to the motor shaft 140. To this end, the impeller base plate 152 can be provided with a central aperture for receiving the motor shaft 140 and can be integrally formed or joined to a tubular sleeve 154 adapted to be joined to the motor shaft 140. In one implementation, the impeller base plate 152 is first attached to the motor shaft 140 and joined, such as through the use of an adhesive. In a second step, the impeller 72 can be advanced over the shaft and the impeller base 150 can be joined to the impeller base plate 152, such as by laser welding.

[0043] The distal opening in the aperture of the impeller base plate 152 may be of increasing diameter in the distal direction to facilitate application of adhesive. The proximal end of the tubular sleeve 154 may be of decreasing outer diameter in the proximal direction to form an exit ramp to facilitate advancing the sleeve proximally over the motor shaft and through the motor seal 156, as discussed further below.

[0044] The pump includes a motor 145 sealed from the bloodstream that is configured to be used for short duration (in some embodiments, about 6 hours or less) high-risk PCI without flushing or purging. This provides the opportunity to bond the impeller 72 directly onto the motor shaft 140, as discussed in more detail below, eliminating issues associated with magnetic coupling, such as additional stiffness length, space requirements, or pump efficiency.

[0045] The motor 145 includes a stator 158 having conductive windings surrounding a cavity that encloses a motor armature (rotor) 160, which may include a number of magnets rotationally fixed to the motor shaft 140. The motor shaft 140 extends from the motor 145 through a rotary bearing 162, through a seal 156, and then out a sealed motor housing 164.

[0046] The seal 156 includes a seal holder 166 backed by an annular seal ring 167, such as a polymer seal ring. The seal ring 167 includes a central aperture for receiving the sleeve 154 or alternatively the drive shaft 140, and is biased radially inwardly relative to the sleeve 154 to maintain the seal ring in sliding sealing contact with the rotatable sleeve 154. A spring 168, for example a garter spring which may be made from spring stainless steel or superelastic nitinol, fits within a groove between the annular seal 167 and the seal holder 166 and applies an inwardly facing force against the flexible annular seal 167, which in turn maintains a contact force between a lip 169 of the annular seal 167 and the rotating shaft 140 or sleeve 154 within the central aperture. The outer surface of the sleeve 154 or drive shaft 140 may be provided with a smooth surface, such as by electropolishing, to minimize wear on the seal. The outer surface of the sleeve 154 or drive shaft 140 may be provided with a surface treatment or coating, such as a hydrophobic or hydrophobic treatment, such as an applied coating or micropatterned surface, to minimize wear on the seals.

[0047] 9B, the orientation of the seal includes placing the annular seal 167 proximal to the seal holder 166 and orienting the seal holder distally toward the impeller 72, with the distal face of the seal holder 166 in contact with the flowing blood. The seal 156 prevents blood from passing through the annular seal and into the motor housing proximal to the seal.

[0048] This is just one example of a seal that may be used with the MCS device and pump 22. Other embodiments of seals that may be used on various MCS devices are described herein, for example, with respect to Figures 10-16C, 18A, 18B, and 19.

[0049] Moreover, the seals, vanes, and other features described herein may be used with a variety of different MCS systems and devices, and vice versa. For example, any of the seals, vanes, and / or other features described herein may be used in conjunction with any of the features, e.g., U.S. Provisional Application No. 63 / 116616, filed November 20, 2020, entitled Mechanical Left Ventricular Support System for Cardiogenic Shock; U.S. Provisional Application No. 63 / 116686, filed November 20, 2020, entitled Mechanical Circulatory Support System for High Risk Coronary Interventions; U.S. Provisional Application No. 63 / 224326, filed July 21, 2021, entitled Guidewire; International PCT Application No. PCT / EP2019 / 076002, filed September 26, 2019, entitled Sealed Micropump; International PCT Application No. PCT / EP2019 / 076002, filed May 16, 2019, entitled Permanent-magnetic radial rotating joint and micropump comprising such a radial rotating International PCT Application No. PCT / EP2019 / 062731, entitled "Rotor bearing system", filed on May 16, 2019; International PCT Application No. PCT / EP2019 / 062746, entitled "Rotor bearing system", filed on June 6, 2019; International PCT Application No. PCT / EP2019 / 064775, entitled "Line device for a ventricular assist device and method for producing a line device", filed on June 6, 2019; and International PCT Application No. PCT / EP2019 / 064780, entitled "Sensor head device for a minimal invasive ventricular assist device and method for producing such a sensor head device", filed on May 30, 2019.International PCT Application No. PCT / EP2019 / 064136, filed on June 6, 2019, entitled "Method for determining a flow speed of a fluid flowing through an implanted, vascular assistance system and implantable, vascular assistance system," International PCT Application No. PCT / EP2019 / 064807, filed on August 7, 2019, entitled "Device and method for monitoring the state of health of a patient," International PCT Application No. PCT / EP2019 / 071245, filed on August 7, 2019, entitled "Bearing device for a heart support system, and method for rinsing a space in a bearing device for a heart support system," International PCT Application No. PCT / EP2019 / 071233, filed on July 9, 2019, entitled "Impeller housing for an implantable, vascular support International PCT application No. PCT / EP2019 / 068434, filed on July 19, 2019, entitled Feed line for a pump unit of a cardiac assistance system, cardiac assistance system and method for producing a feed line for a pump unit of a cardiac assistance system, and / or International PCT application No. PCT / EP2019 / 069571, filed on September 24, 2019, entitled Method and system for determining a flow speed of a fluid flowing through an implanted,The present invention may be used in conjunction with the features of the MCS systems and devices described in International PCT Application No. PCT / EP2019 / 075662, entitled "Method and Apparatus for Providing a Vascular Assistance System," the entire disclosures of each of which are incorporated herein by reference for all purposes and form part of the present specification and description.

[0050] B. Control of motor speed by a device with a rotating shaft seal The controller 180 may be adapted to power the motor 145 to maintain a target motor speed even as the current draw changes. The rotational speed of the impeller is directly related to the rotational speed of the drive shaft because the impeller and drive shaft are rigidly connected. The flow rate of blood moved by the impeller is a function of the rotational speed of the impeller. The contact surfaces of the lips of the rotating shaft seal or the elastomeric fluid barrier may be designed to wear during the duration of use. The frictional force applied to the rotating shaft by these parts may be expected to decrease over time as the parts wear. Motor current draw in a brushless DC motor, which is a function of frictional force, and other factors such as pressure differential, may similarly decrease over time in response to the decrease in friction. One way for the controller to detect the motor speed may include the use of a Hall sensor in the MCS pump 22 or another part of the device, which provides a signal to the controller that is indicative of the rotational speed. Alternatively, a field oriented control (FOC) motor may be used, which advantageously allows the MCS device to be smaller by eliminating the need for additional sensors. Smaller MCS devices (e.g., <18FR, <16FR, <14FR, approx. 14Fr) may be particularly advantageous for high-risk PCI procedures. The FOC motor may be used to measure the back EMF generated while the motor is spinning. This back EMF has a rhythmic characteristic (e.g., sinusoidal) that represents the frequency of the motor's rotation, which may be detected by the controller as a feedback signal for a control algorithm that may include a form of PID (proportional integral derivative) control. The controller may adjust the current delivery to the motor according to the feedback signal to adjust the motor speed, thereby matching a target speed, which may include a tolerance for small variations around the target, for example, a ±0.006% variation in the target motor speed (e.g., approx. 250 rpm for a target speed of 40k rmp) may be tolerated without the controller adjusting the motor current.

[0051] C. Seal configuration and sealing principle Without being bound by theory, rotary shaft lip seals are typically oriented so that the lip faces the high pressure side, i.e., the side that has the fluid that the seal is intended to prevent from flowing to the other side. For example, the seals shown in Figures 9B, 10, 11, 13A, and 13B are shown oriented in this manner. For example, as shown in Figure 9B, seal 167 has a radially inner lip 169 that extends distally from a proximal side 165 of seal 167. The open distal side of seal 167, which has a cavity, faces distally toward the fluid side and impeller 72, and the opposite proximal side 165, which may be flat, faces proximally in the opposite direction toward motor 145.

[0052] A conventional sealing arrangement may have a seal 167 with an open side facing distally as described, and may have an inner lip 169 that contacts the rotating shaft. Liquid on this open lip side of the seal may contact the intersection of the contact lip 169 and the rotating shaft 140, and a very small amount of liquid may form a layer between the lip 169 and the shaft 140. If the liquid is blood, some components of the blood, such as proteins, may be affected by mechanical forces or heat in this area and cause them to clot or adhere to the shaft, reducing the life of the seal material or duration of the seal's functionality, or posing a safety hazard to the patient. Features described in connection with FIGS. 9B, 10, 11, 13A, and 13B, such as grease, a distal guard disk, a distal guard disk with a contoured surface, and / or impeller proximal vanes, may mitigate this risk.

[0053] Conversely, if the seal is oriented in the opposite direction (such as the orientation shown in FIG. 12 ) with the lip and seal cavity facing away from the blood and including a supply of lubricating grease within the seal cavity, the liquid contacting the lip-shaft intersection may be preferentially lubricant, which may slow or eliminate the buildup of blood particles. Some of the embodiments described herein are based on the discovery of this "reverse" or "rear" orientation of the seal.

[0054] Furthermore, the conventional approach to sealing is to "keep fluid out". However, the seal configuration described herein can be designed based on the principle of "keep lubricant in", which in turn has a superior effect in keeping fluids (such as blood) out. For example, including two seals facing each other, such as shown in Figs. 14A, 14B, 14C, 15, 16A, or 19, can provide additional benefits. Each seal cavity can act as a reservoir for lubricant, such as grease. Two seal cavities facing each other can create a larger reservoir for grease, and the seals can act to keep the grease in the reservoir and prevent or slow the grease from leaking, while the lubrication of the grease designed to withstand mechanical or thermal stress is the liquid that contacts the lip-shaft intersection, not the blood. Thus, the sealing arrangement provides a blood barrier based on the principle of keeping grease in.

[0055] D. Embodiments with a Single Seal and Distal Disk FIG. 10 is a cross-sectional view of another embodiment of the impeller region of an MCS device having an alternative seal configuration. This embodiment is similar to the embodiment of FIG. 9B, except that a distal protective disk 255 (also referred to as distal disk 255) is disposed distal to the annular seal. The distal protective disk provides at least a partial barrier between the patient's blood and the annular seal assembly, which includes a seal holder 166, an annular seal 167 having a sealing lip 169, and a garter spring 168. The distal protective disk functions to reduce contact between the blood and the seal by closing off a majority of the opening in the motor housing 164 through which the seal is initially inserted. Thus, the distal protective disk covers a majority of the seal that would otherwise be exposed to blood. The distal protective disk also allows blood to travel a greater distance before it reaches the seal, and acts as an insulator between the blood and heat-generating areas of the device, such as the motor or seal, reducing the risk of blood damage or clotting. The distal protective disk 255 may be shaped like a circular disk, with a central hole 171 through which the drive shaft may pass, and a thickness 172, e.g., uniform thickness. The distal protective disk 255 may fit tightly (e.g., may be sealed) against the motor housing 164, and thus have a diameter equal to or slightly larger than the inner diameter of the motor housing to form a tight fit (e.g., a friction fit). Optionally, the distal protective disk may have a form-fitting feature 173, such as a protruding ring around its outer periphery, or a groove that mates with a form-fitting feature of the motor housing 164, for additional fastening and sealing. Optionally, the distal protective disk may be bonded to the motor housing with an adhesive or welding. The central hole 171 is sized to have a very small gap (e.g., a gap of 0.05 mm or less, 0.01 mm or less) between the distal protective disk 255 and the motor drive shaft 140, and the gap may include the impeller proximal extension 154 passing through the central hole. In some embodiments, the distal protective disk does not come into contact with the drive shaft 140 passing through the central hole, ensuring that no additional friction is created or additional torque loss occurs.For example, the central hole 171 may have a diameter equal to the diameter of the drive shaft (140) plus twice the small gap (e.g., if the drive shaft has a diameter of 0.6 mm, the central hole may have a diameter in the range of 0.62-0.70 mm). Optionally, a portion of the central hole may have an inner diameter smaller than the outer diameter of the drive shaft to contact and act as a barrier to fluids. The thickness 172 may be in the range of 0.1 mm to 1.5 mm (e.g., 0.3-1.2 mm, about 1 mm). The distal protective disk may be made from a polymer such as PEEK, PTFE, or elastomeric polyurethane, which may beneficially act as an insulator, allow for slight deformation when fitting into the motor housing, or minimize friction in situations where the drive shaft (140) contacts the disk temporarily or inadvertently. Additionally, the slippery surface of the material may enhance blood flow in the axial gap 174, i.e., the space between the impeller 72 and the stationary components facing the impeller, in this case the motor housing 164 or the distal guard disk. Alternatively, the distal guard disk may be made from a metal such as titanium or steel. Another feature of the distal guard disk 255 is the inclusion of a lubricating grease 175 within the seal cavity 176.

[0056] The seal cavity 176 is the volume of space within the seal where grease may be stored. For example, the seal cavity 176 shown in FIG. 10 may be the volume of space defined by the seal holder 166, the annular seal 167, and the distal protective disk 173. The garter spring 168 may also be contained within the seal cavity 176. In the configuration shown in FIG. 10, the seal cavity 176 faces distally, i.e., toward the impeller.

[0057] 10, the impeller 72 may optionally be connected to an impeller base plate 152, which may optionally have proximal vanes 177. Alternatively, the impeller may be directly connected to the motor drive shaft 140, and the device may or may not have proximal vanes.

[0058] A method of manufacturing the device shown in FIG. 10 may include dispensing grease into the seal cavity 176 containing the garter spring 168 before assembling the seal components (e.g., seal holder 166, annular seal 167, spring 168) into the motor housing 164. To completely fill the seal cavity and surround the spring with grease, the seal components containing the dispensed grease may be spun in a centrifuge or evacuated in a vacuum chamber to remove any air bubbles. The seal components may then be pressed into the motor housing and additional grease may be added into the seal cavity or distal to the annular seal 167 before covering with the distal protective disk 255.

[0059] E. An embodiment having a single seal with a distal disc and a proximal disc As shown in Fig. 11, the MCS device may have both the distal protective disk 255 described in connection with Fig. 10, for example, and a proximal disk 275 (also referred to as the proximal disk) disposed adjacent and proximal to the annular seal 167 and distal to the motor bearing 162 and motor. The proximal disk 275 may function to reduce contact between the motor bearing or motor and the blood by sealing most of the path and increasing the distance the blood must travel before reaching the motor. For example, if blood has passed the distal protective disk 255 and the annular seal 167, the proximal disk 275 may act as an additional means to prevent blood from flowing further into the motor housing. The combination of a distal protective disk 255 distal to one or more annular seals 167 and a proximal disk 275 proximal to one or more annular seals 167 may limit or reduce the passage of blood from the external environment to the motor and may reduce heat transfer from the motor or bearings 162 to the annular seal 167, or to blood in the external environment, or to blood contacting surfaces.

[0060] Another benefit is that the proximal disk 275 together with the annular seal may define a proximal cavity 189 on the proximal side of the annular seal 167 in which a second reservoir of lubricant or grease may be located. Optionally, the first reservoir of lubricant or grease may be located in the seal cavity 176, in this case on the distal side of the annular seal 167. Having a first and second reservoir of lubricant or grease on each side of the annular seal may further reduce friction between the annular seal and the drive shaft by providing a larger amount of grease or by providing grease on each side of the annular seal to ensure that there is a continuous layer of grease between the annular seal lip 169 and the moving parts that interact with the lip, such as the drive shaft 140 or the impeller proximal extension 154, thereby extending the duration of the seal integrity. Optionally, the first lubricant contained within the seal cavity 176 and the second lubricant contained within the proximal cavity 189 may be different substances. For example, the first lubricant may be a higher consistency grease (e.g., NLGL grade 3-4) that may function to remain mostly contained within the seal cavity 176 and surround the garter spring 168 to prevent blood from entering the garter spring 168 for at least the duration of use. The second lubricant may be a relatively low consistency grease that may function primarily to lubricate the seal lip 169. A portion of the second lubricant may also contact the seal lip 169, interacting moving surfaces, or distal protective disk to provide a low friction interaction. Alternatively, the same grease may be used in the seal cavity 176 and the proximal cavity 189.

[0061] A method of manufacturing the device of FIG. 11 may include, in addition to the grease dispensing step described above in connection with FIG. 10, the additional step of forcing the proximal disc 275 into the motor housing 164 and dispensing a first store of grease or lubricant into the proximal cavity 189 prior to forcing the sealing components into the motor housing.

[0062] F. Embodiments with a Single Inversion Seal and Proximal Disk Another implementation of an MCS device with a sealed rotating shaft is shown in the cross-sectional view of FIG. 12, where the rotating shaft lip seal 167 is oriented with its contact lip 169 and seal cavity 176, or its "open" side, facing proximally, i.e., toward the sealed motor 145 and away from the impeller 72. The opposite distal side, which may be flat as shown, faces the fluid side and the impeller. A proximal disk 275 is positioned proximally of the lip seal 167, and lubricating grease is deposited in the space defined by the seal cavity 175 and the proximal disk 275. Optionally, the MCS device may have an impeller with proximal vanes to increase blood flow in the axial gap 174, which may beneficially remove heat from the seal contact area to reduce the risk of blood clotting. Optionally, the lip seal 167 may have a leading edge 231 (see FIG. 14B) to further prevent blood from passing through the seal.

[0063] G. Embodiments with Distal Guard Disk and Contoured Flow Surface Another implementation of an MCS device with a sealed rotating shaft is shown in the cross-sectional view of FIG. 13A. As shown, the cross-sectional view of the MCS device has a distally facing lip seal 167, a distal protective disk 212 with a distally facing conical surface 214 with a concave contour, and an impeller 210 with blades having a proximal region 211 that matches the contoured surface. The distal protective disk 212 may be made of an elastomeric material such as PTFE, PEEK, or a compound, and has a central bore 213 with an inner diameter that is slightly larger than the position of the rotating shaft within the central bore, thereby minimizing or avoiding contact. For example, the radial gap between the rotating shaft 140 and the distal protective disk 212 may be in the range of 40 μm to 75 μm (e.g., about 0.05 mm). Optionally, the distal protective disk may at least partially contact the rotating shaft. Optionally, at least a portion of the central opening 213 has a diameter smaller than the outer diameter of the drive shaft 140, optionally by a difference in the range of 0.01-0.05 mm. The distal protective disk 212 may protrude from the motor housing 164 (e.g., by a distance in the range of 1-2 mm), which may increase the distance between the seal 167 and the flowing blood, which in turn may prevent blood from entering the seal for a longer period of time or may insulate the blood from heat generated in the motor. The protruding portion of the distal protective disk may have a contoured surface, for example a tapered or conical portion 214, optionally having a concave surface, and a flat surface portion 215. The flat surface portion 215 may have a diameter equal to or similar to (e.g., within 0.01 mm) the diameter of the flat portion of the base of the impeller 210. The shape of the tapered portion 214 may smoothly transition from the shape of the impeller hub 146, which may facilitate directing blood flow from the inlet tube 70 out of the outlet window 68. A narrow axial gap 174 is between the impeller 210, which has blades with proximal regions 211 that coincide with a contoured surface.

[0064] Alternatively, as shown in FIG. 13B, the MCS device may have a distally facing lip seal and a distal protective disk having a contoured surface with an impeller 72 having a mismatched proximal shape, such as a flat proximal edge 225.

[0065] Alternative implementations can have a distal protective disk with a contoured surface and an impeller with a matching contour as shown in FIG. 13A, or an impeller with a non-matching contour but with a proximally facing lip seal and optional proximal disk as shown in FIG. 13B.

[0066] H. Embodiment with Two Radial Shaft Seals Another embodiment of an MCS device having a sealed rotating shaft is shown in Figures 16A-16G. Figure 16A is a partial cross-sectional view of an MCS device having two facing lip seals (aka radial shaft seals), a distal disk, a middle disk, and a proximal disk contained within a seal housing, Figure 16B is a partially cut away isometric exploded view thereof, and Figure 16C is a cross-sectional view of the seal components shown individually as a subassembly. Figure 16D shows an alternative embodiment of a seal assembly having a proximal disk with enlarged radial and axial contact surfaces, Figure 16E shows an embodiment of an MCS device having a sealed rotating shaft and a tapered vessel, and Figures 16F and 16G show an embodiment of an MCS device having a sealed rotating shaft and a tapered vessel with an output strut, as further described herein.

[0067] As shown in FIGS. 16A-16C, the device includes a distal annular radial or rotary shaft seal 266 having a radially inwardly facing contact lip 267 that forms a seal cavity 176a. The contact lip 267 and seal cavity 176a of the distal seal 266 face proximally. Thus, the distal seal 266 has an "open side" that faces proximally toward the motor and a "flat side" that faces distally toward the impeller and blood. Thus, the distal seal 266 is oriented "backward" from a conventional orientation. In some embodiments, the "open side" can be a side of the seal 266 that is formed in part by the top and / or bottom flanges or lips of the seal 266. A cavity can be formed by the open side of the seal 266. The cavity can be formed between an end wall of the seal 266 and one or more flanges or lips of the seal 266. The cavity can have a spring and / or grease located therein. Further details of the end walls, lips, etc. are provided herein.

[0068] The device further includes a proximal annular radial or rotating shaft seal 270 having a radially inwardly facing contact lip 271 that forms a seal cavity 176b. The contact lip 271 and seal cavity 176b of the proximal annular seal 270 face distally. Thus, the proximal seal 270 has an "open side" (as described above) that faces distally toward the motor, and a "flat side" that faces proximally toward the impeller and blood. Thus, the seal assembly includes the proximal annular seal 270 and the distal annular seal 266 having opposite orientations, with their contact lips 267, 271 and seal cavities 176a, 176b facing each other.

[0069] Lips 267, 271 contact shaft 140. Lips 267, 271 may extend along shaft 140. All or a portion of one or more radially inwardly facing surfaces of lips 267, 271 may contact shaft 140. Lips 267, 271 may be flat and / or have non-flat features, as described in more detail herein, for example, with respect to FIG.

[0070] The seals 266, 270 may include radially outer lips 263, 264. The lips 263, 264 may contact a radially inward facing surface of the housing or other component of the seal segment. The lips 263, 264 may extend along the housing or other component. The lips 263, 264 may seal a space between the seals 266, 270 and the housing or other component. The radially outer surfaces of the lips 263, 264 may be flat, uneven, or a combination thereof.

[0071] Lips 263, 264 may extend from the respective end walls 262, 259. Lip 263 extends distally from end wall 262. Lip 264 extends proximally from end wall 259. End walls 262, 259 may refer to "flat" sides as described herein. Radially inner lips 267, 271 may extend from end walls 262, 259 as described. Outer lips 263, 264 may extend perpendicular to end walls 262, 259 either when no external force is applied and / or when installed within the seal compartment. Outer lips 263, 264 may have the same or similar features as inner lips 267, 271, such as a leading edge, a groove, or a recess.

[0072] In some embodiments, the intermediate elastomeric disc 260 may be positioned between the proximal annular seal 270 and the distal annular seal 266. The distal elastomeric disc 255 may be positioned distal to the distal annular seal 266. The proximal elastomeric disc 275 may be positioned proximal to the proximal annular seal 270.

[0073] Optionally, a seal housing made of distal seal can 240 and optional seal can cap 278 (see FIGS. 16B, 16C, and 16D) may contain the seal components in a subassembly. The subassembly may be inserted into motor housing 164 over drive shaft 140. Alternatively, the seal components may be assembled into the motor housing by inserting the components separately, sequentially, into cavities in the motor housing over drive shaft 140. The seal components may then be covered with a proximal seal cap 278, which may be attached (e.g., welded, friction-fit, form-fit, glued) to the motor housing.

[0074] Both the distal elastomeric disk 255 and the intermediate elastomeric disk 260 may be made of an elastomeric biocompatible material such as PTFE, elastomeric polyurethane, or a compound material such as PTFE and polyimide. As shown in FIG. 16B, one or more of the disks 255, 260 may have an inner diameter (ID) 256, 261 that is smaller than the outer diameter (OD) of the drive shaft 140, which may optionally include an impeller proximal extension 154 such as that shown in FIG. 10 where the inner diameters meet. For example, the ID 256, 261 may be in the range of 80%-95% (e.g., about 87%) of the OD 141. In one implementation, the ID 256, 261 is 0.52 mm + / - 0.02 mm and the OD 141 is 0.60 mm + / - 0.01 mm. This dimensional difference creates a high interference between the elastomeric disks 255, 260 and the drive shaft to maintain a seal. For example, the ideal interference may be in the range of 0.070 mm to 0.080 mm. The elastomeric discs 255, 260 may both have a thickness in the range of 80 μm to 140 μm (eg, about 100 μm).

[0075] The properties of the elastomeric disks 255, 260, such as high interference, material durometer (e.g., in the range of 70-85 Shore), and thickness, may allow the disks to deform when inserted over the drive shaft. For example, the disks may compress outward so that the disk ID may stretch, or the plane of the disk may curve, especially in areas close to the ID. The deformation of the disks may provide contact pressure with the drive shaft 140 even as the disk material wears over time. Additionally, high interference provides an amount of material that can be worn before the contact pressure is reduced to zero, which may extend the functional duration of the disks 255, 260 to act as a blood barrier. Additionally, high interference may compensate for small tolerances of the eccentricity of the drive shaft within the disk.

[0076] The properties of the disks 255, 260 may allow the disks 255, 260 to act as a fluid barrier for at least a portion of the intended duration of use of the MCS device while minimizing friction or reduced torque transmission. Additionally, the distal elastomeric disk 255 may act as a first barrier to blood for at least a portion of the duration of use. The intermediate elastomeric disk 260 may act as an additional barrier to blood if the blood has passed through the more distal barrier. Also, the disk 260 may act as a partition between the distal and proximal annular seal cavities 176a, 176b, helping to keep the grease contained within these cavities next to each annular seal, which in turn extends the functional duration of the annular seals. Optionally, the grease or lubricant dispensed within the distal seal cavity 176a may be the same or different as the grease or lubricant dispensed within the proximal seal cavity 176b. In some embodiments, the proximal disc 276 may have the same or similar features as the distal and intermediate discs 255, 260.

[0077] Other than their relative positions and orientations, the distal seal 266 and the proximal seal 270 may have similar properties to each other or to other seals 156 disclosed in connection with other implementations. For example, both the distal and proximal seals may have a seal holder 265, 274, an annular seal having a contact lip 267, 271, a seal cavity 176a, 176b defined in part by the seal holder and the annular seal, and / or a garter spring 269, 273 retained within the respective seal cavity 176a, 176b. The seals 266, 270 may have the same inner diameter and lip dimensions. Optionally, the seals 266, 270 may have primarily different outer diameters so that they are easily distinguishable from each other during manufacturing.

[0078] As an alternative to garter springs 269, 273, the seal may include a different component that applies the radially inward force, such as an O-ring, or may not have a separate component that applies the force, where the nature of the elastomeric annular seal with contact lips applies the radially inward contact force itself.

[0079] The distal and proximal annular seals 266, 270 may be made from a biocompatible elastomeric material such as PTFE, an elastomeric polyurethane, or a compound material such as PTFE and polyimide, which may optionally have one or more additives for enhanced durability. Grease may be contained in one or both seal cavities 176a, 176b and, optionally, in a third grease reservoir held between the proximal seal and the proximal disc 275, and may be the same or a different grease. In one implementation, a first grease is deposited in the distal seal cavity, which may have a higher viscosity and grease consistency (e.g., NLGL Class 4 or higher) than the third grease deposited in the proximal seal cavity (e.g., NLGL Class 2) or the second grease held in the third grease reservoir held between the proximal seal and the proximal disc. In another implementation, grease is deposited in the distal seal cavity (eg, NLGL Class 4 or above) and oil is deposited in the proximal seal cavity.

[0080] Optionally, distal seal 266 may have a leading edge 231 on its distal face, which is the surface of the distal seal that contacts a rotating component, such as drive shaft 140, in addition to a contacting lip 267. Leading edge 231 is a portion of distal annular seal 266 that has an inner diameter smaller than the inner diameter of a portion of contacting lip 267 located proximal to leading edge 231. Leading edge 231 may be a portion of distal annular seal 266 that has an inner diameter smaller than the outer diameter of motor drive shaft 140 with which it mates. For example, the ID of the leading edge may be in the range of 75%-95% (e.g., 80%-90%, about 87%) of OD 141. In one implementation, the ID is 0.52 mm and OD 141 is 0.60 mm. By providing a flush connection to the rotating shaft 140 on the distal face of the seal, the leading edge may function to reduce the occurrence of blood being actively drawn under the contacting lip 267, which may contribute to an extended seal life. The distal annular seal 266 may be fabricated with a groove between the leading edge 231 and the contacting lip 267, as shown. The leading edge 231 may be formed in part by an adjacent groove or recess formed in the inner surface of the lip 267. Alternatively, the leading edge 231 may have a smooth transition to the contacting lip 267.

[0081] The orientation of the proximal seal 270, with the contact lip 271 and seal cavity 176b facing distally, may facilitate the overall sealing function in several ways, for example, a lubricating grease may be held within cavities 176b and 176a between the distal seal 266 and the proximal seal 270, which may cover the contact surfaces between the contact lips 267, 271 and the drive shaft 140 to reduce wear, minimize reduced torque transmission or heat generation, and resist blood ingress, where the higher pressure on the distal side of the seal 270 compared to the proximal side (e.g., due to compressed grease held within the seal cavity 176b or if blood has passed through a more distal blood barrier) may aid in the contact pressure of the contact lip 271. The axial length of the portion of the contact lip 271 that contacts the shaft may be in the range of 0.3-0.8 mm (e.g., about 0.5 mm).

[0082] Optionally, the device may have a proximal disc 275 positioned proximal to the proximal seal 270, as shown in FIG. 16A. The proximal disc may act as another barrier to prevent blood from entering the drive shaft bearing 162 or the motor compartment. Additionally, the proximal disc may help to account for small tolerances in the eccentricity of the drive shaft. The proximal disc 275 may be made of a biocompatible elastomeric material or compound, such as PTFE or elastomeric polyurethane, and may have a generally disc shape with a central hole with an inner diameter 276 through which the drive shaft 140 passes and contacts. The ID 276 may be in the range of 80%-97% (e.g., about 93%) of the OD 141. In one implementation, the ID is 0.56 mm and the OD 141 is 0.6 mm, which may be larger than the ID of the distal disc 255 or the middle disc 260 to have less impact on torque transmission losses. Optionally, the proximal disc 275 may be thicker than the distal or intermediate discs 255, 260, as shown in FIG. 16A, which, along with the elastomeric nature of the discs, may provide axial compression of the sealing components when the proximal disc is compressed between the distal seal receptacle 240 and the edge on the motor housing 164. For example, the thickness of the proximal, intermediate, and distal discs may range from 0.10 mm to 0.15 mm. The proximal disc 275 may be axially compressed by the dimensions of the stack of axial seal components and the space within the housing that compresses the stack. In some embodiments, the proximal disc 275 may be non-flat, for example, spherical, such as a Belleville washer shape, to provide compression.

[0083] 16B and 16C show the device of FIG. 16A but with a relatively thinner proximal disk 275 and with the addition of a sealed can cap 278. In this implementation, all sealing components are contained within the sealed can, for example as a subassembly. The sealed can can include a distal sealed can 240 and a sealed can cap 278, both of which can be made from a metal such as stainless steel or titanium and can be securely connected, for example, with a friction fit, a form fit, threading, or welding.

[0084] 16D illustrates a seal 156 having the same features and functionality as the seal of FIG. 16B, unless otherwise noted. For example, the seal 156 of FIG. 16D includes a proximal disk 275 having a first thickness 282 in an axial direction and a second thickness 283 that is greater than the first thickness 282 in an axial direction. The second thickness 283 can be located closer to the central axis 185 relative to the first thickness 282. The second thickness 283 can be at least as thick as the combination of the first thickness 282 and the thickness of the sealed container cap 278. The second thickness 283 can be thicker than the combination of the first thickness 282 and the thickness of the sealed container cap 278, such that a proximally facing protruding surface 284 protrudes from the cap 278 in a proximal direction (i.e., to the right in the orientation of the figure). When assembled, the proximal-facing protruding surface 284 may slidably contact a distal-facing surface (see FIG. 16A ) of at least a portion of the drive shaft bearing 162 to provide another layer of sealing. The increased second thickness 283 allows for a larger radially inner surface 285 to provide slidable contact with the motor shaft 140, which may enhance sealing performance.

[0085] 16B, the distal seal canister 240 serves to contain the seal components with or without a seal canister cap 278, facilitating manufacturing. The distal seal canister may have a flat, rigid distal surface 241 that provides a surface for mechanically forcing the seal components into the motor housing 164 while protecting the softer, more fragile seal components. The flat, rigid surface 241 also ensures that the axial gap 174 between the surface 241 and the impeller is consistent, so that blood in the axial gap is expelled and the proximal face of the rotating impeller does not inadvertently contact the seal components. The surface 241 has a central bore 242 with an inner diameter larger than the outer diameter of the drive shaft 140. For example, the hole 242 may have a diameter in the range of 0.080 mm to 0.150 mm larger (e.g., about 0.100 mm) than the outer diameter of the rotating component passing through the hole, which may act as a physical filter to prevent particles from escaping from the container as a risk control measure. For example, the hole 242 may be in the range of 0.68 mm to 0.75 mm (e.g., about 0.70 mm) if the drive shaft has a diameter of 0.60 mm. In other words, the radial gap between the drive shaft and the container 240 may be in the range of 0.040 mm to 0.075 mm (e.g., about 0.050 mm). The distal seal container has a cylindrical sidewall with an inner surface 248 that serves to constrain the seal components, ensuring that there is no lateral movement that could compromise the integrity or life of the seal. The proximal chamfer 244 facilitates insertion into the motor housing during manufacturing. The distal chamfer 243 facilitates insertion of the inlet tube 70, or alternatively the impeller housing 82, over the distal seal canister 240. Additionally, the distal seal canister 240 may have a recessed outer surface 245 for insertion into the motor housing 164. An embodiment of a heart pump 22 having a seal element 156 as shown in FIG. 16A may have a motor housing that is 25.5 mm in length or less. With the additional length added to the motor housing by the seal subassembly and optional wiring module connected to the proximal end of the motor housing, the length of the motor housing may be extended to 33 mm or less.

[0086] In another embodiment, as shown in FIG. 16E, the MCS device may have a seal 156 in the form of a seal assembly, where the distal seal canister 240 does not have a flat distal surface 241 as shown in FIG. 16A, but instead has a distally tapered, e.g., conical, surface 321. The distally tapered conical surface 321 may have a straight slope (as shown in FIG. 16E), or alternatively may have a curved slope, e.g., a concave profile like surface 214 shown in FIG. 13A, or a convex conical profile, or a combination thereof. Due to the inner geometry of the seal canister with a conical distal surface 321 compared to a flat distal surface, a portion of the seal component may extend inside the tapered portion of the distal seal canister 240. This may reduce the length of the rigid motor housing. A shorter rigid motor housing beneficially traverses curves such as the aortic arch more easily.

[0087] Additionally, the central hole 242 in the distal seal container 240 is longer in the cone-shaped container (FIG. 16E) compared to the flat-shaped container (FIG. 16D), and this additional length provides space for additional sealing functionality. The distal disk 255 may have a tubular extension 322 lining the inner surface of the central hole 242. The tubular extension 322 may be part of the distal disk 255 and may be of the same material as the distal disk 255, e.g., PTFE, and may optionally be bonded to the surface of the central hole 242. The inner surface of the tubular extension 322 may be configured to further extend the duration of the sealing performance by slidably engaging the motor shaft 140 to create another sealing functionality. In some embodiments, the tubular extension 322 may have a surface texture or treatment on the inner surface intended to at least partially contact the motor shaft 140. The surface texture or treatment may be included on the protruding circumferential ribs, indentations, or micropatterns, which may be hydrophilic or hydrophobic, which may function to prevent the passage of blood or to retain lubrication. In some embodiments, the distal disk 255 and / or the tubular extension 322 may be made from a material that retains lubrication, such as felt. In some embodiments, a cavity may be created in the conical portion of the distal seal receptacle 240 to retain lubrication. The tubular extension 322 may terminate so that its distal axial face 232 is flush with the distal opening in the distal seal receptacle 240, or may extend beyond the receptacle 240 and optionally contact the impeller hub 146 to create an axial face seal. The length of the tubular extension 322 that extends beyond the seal receptacle 240 may be approximately 100 microns to provide adequate space between the impeller and the distal seal receptacle. In the configuration shown in FIG. 16E, the impeller 72 may not include an impeller base 150 as shown in FIG. 17. Additionally, the impeller vanes or blades 178 may have a flat proximal edge 225 as shown in Figures 13B and 16G, or may have a proximal edge 211 that extends proximally to follow the distal contour 214, 321 of the distal seal can 240 as shown in Figures 13A, 16E, or 16F. The "flat proximal edge" 225 may have an edge that is substantially perpendicular to the central axis.In some embodiments, the flat proximal edge 225 or contoured proximal edge 211 of each impeller vane 178 may be connected to one another via the impeller hub 146, but may not be connected via an impeller base, such as the impeller base 150 shown in Figures 17A, 17B, and 17C, or the impeller base plate 152 shown in Figure 14A. In other words, there may be an open space defined by the impeller blades 178 through which blood flow may be directed axially and proximally toward the distally tapered surface 321, where blood flow is directed radially outward through the outlet window 68.

[0088] Figures 16F and 16G are perspective and side views, respectively, of a different embodiment of a portion of an MCS apparatus with the motor, motor housing, and motor shaft removed to more clearly illustrate the seal receptacle 240, impeller 72, and inlet tube 70. The inlet tube 70 is shown transparent to reveal the impeller 72 and seal receptacle 240. The MCS apparatus of Figures 16F and 16G may include any of the seal assemblies described herein, such as the seal assemblies of Figures 16C, 16D, etc.

[0089] 16F and 16G show an alternative embodiment of the distal seal vessel 240 further comprising an outlet strut 195. As further shown, in some embodiments, the device may include an outlet strut 195 having an outlet strut auxiliary 325. The outlet opening or window 68 is an opening in a cylindrical flow cannula, such as an inlet tube 70 or an impeller cage that contains an impeller that moves blood from the inlet to the outlet window through the cannula. The outlet strut 195 is a structure that holds the cannula to the motor housing directly or indirectly. The outlet strut 195 may include one or two or three or four or more webs that are axially elongated and radially disposed about the longitudinal axis of the cannula. The outlet strut 195 may be made by laser cutting the outlet window 68 in the inlet flow cannula 70, and the remaining material between the outlet windows may be the outlet strut 195, which may be substantially equal in geometry.

[0090] The outlet strut auxiliary 325 may be connected to the distal seal can 240 or may be machined as part of the distal seal can 240, and may each include a rigid structure that spans between the distal seal can 240 and the outlet strut 195, preferably over the location of the outlet strut between its proximal and distal ends, to increase the stiffness and bending resistance of the outlet strut. The outlet strut auxiliary 325 may have an axial length 326 that is a portion (e.g., up to 100%, up to 50%, up to 30%, about 30%) of the outlet strut length 327. The outlet strut auxiliary 325 may have an axial length 326 that is a portion (e.g., up to 100%, up to 50%, up to 30%, about 30%) of the axial length of the conical portion 321 of the distal seal can 240. For example, Figure 16G shows an exit strut support 325 having an axial length 326 that is 100% of the length of the conical portion 321, and Figure 16F shows an exit strut support 325 having an axial length 326 that is about 40% of the length of the conical portion 321. The exit strut support 325 may contact the exit strut 195 or may be bonded to the exit strut 195 and may be made of a rigid material that provides the exit strut 195 with increased strength or resistance to bending.

[0091] The outlet strut complement 325 may further function to direct blood flow from the inside of the outlet strut 195 towards the outlet window 68. For example, the outlet strut complement 325 may have an angled surface in the direction of blood flow (i.e., distal to proximal) or within the outlet window 68 space from a location on the radially inner surface of the outlet strut 195 to a location on the radially outer edge of the outlet strut. The outlet strut complement 325 may have a leading edge 328 that is configured to face upstream in the blood flow and may be rounded. In FIG. 16F, the leading edge 328 is positioned in the center of the width of the outlet strut 195, and the outlet strut complements 325 each have an angled surface from the leading edge 325 to each adjacent outlet window 68 on each side of the outlet strut complement. Alternatively, as shown in FIG. 16G, the outlet strut support 325 may have a leading edge 328 that is asymmetrically positioned on the outlet strut 195, for example near the edge of the outlet strut, for example near the edge of the outlet strut that faces the radial component of the blood flow.

[0092] A method of manufacturing the seal subassembly may include, but is not limited to, inserting the seal components into the distal seal receptacle in the order and orientation described herein, dispensing grease into the seal cavity, optionally sequentially or simultaneously, expelling air bubbles using a centrifuge or vacuum chamber, and closing the seal receptacle with a seal receptacle cap 278. The seal subassembly may be inserted over the drive shaft 140, optionally into the motor housing, and connected to the motor housing by, for example, laser welding the intersections, which may include rabbet 246 of the distal seal receptacle 240 and rabbet 247 of the motor housing. The impeller may be connected to the drive shaft, for example, in the arrangement described herein in connection with FIG. 9B, 18A, or 18B. The impeller housing 82 or inlet tube 70 with an integrated impeller housing may be connected to the motor housing and / or the distal seal receptacle 240. The device may be packaged in an airtight package with air evacuated to prevent drying of the grease dispensed into the seal.

[0093] Alternative implementations of the concept shown in Figure 16A are shown in Figures 14A, 14B, and 14C, which have two rotating shaft lip seals oriented with their contacting lips facing each other. The embodiments of Figures 14A, 14B, and 14C can have the same or similar features as those described for the seals of Figures 16A-16C, and vice versa.

[0094] As shown in FIG. 14A, the seal may not have a distal, middle, and proximal disk. Optionally, only one of the two seals may contain a garter spring, which may allow more grease to be deposited in seal cavity 176b in addition to seal cavity 176a, which contains the garter spring. The two seals may be inserted into the motor housing 164, and a rigid metal cap may be positioned over the seals and welded to the motor housing. Alternatively, the two seals may be contained in a sealed container 240, such as the one shown in FIG. 16C, and inserted as a component into the motor housing.

[0095] 14B shows a similar implementation, but with garter springs in both the distal and proximal seals, and the distal seal has a leading edge 231 configured to contact the rotating shaft distal to the contact lip.

[0096] 14C shows another similar implementation, but the distal seal does not have a leading edge. Instead, the device has an elastomeric distal disk 255 that is sized to contact the rotating shaft with a contact pressure that can act as an additional barrier to blood.

[0097] I. Embodiments with Pressure Balancing Mechanism The embodiment of Figure 15 includes a pressure balancing mechanism. Optionally, MCS devices having one or more rotating shaft seals, such as those shown in Figures 9B-16C, 18A, 18B, or 19, may include a pressure balancing mechanism.

[0098] The pressure balancing mechanism may communicate or otherwise transfer pressure between the surrounding blood and the grease held within the seal cavity. Without being bound by theory, a pressure gradient between the surrounding blood pressure on the outside of the seal component and the grease pressure on the inside of the seal component may cause blood to enter the seal or lubricant to leave the seal. By balancing the pressure and reducing or eliminating the pressure gradient, blood or lubricant flow may be minimized. This may enable the device to prevent backflow of blood and extend the duration of functionality. The pressure balancing mechanism may be employed with any of the seal implementations disclosed herein and may be used with one or more rotating shaft lip seals, one or more axial face lip seals, seal disks, seal receptacles, or with distally or proximally oriented seals, particularly with at least one seal whose seal cavity is proximally oriented.

[0099] For example, as shown in FIG. 15, the pressure balancing mechanism may be employed with two rotating shaft seals with their seal cavities 176a, 176b oriented toward each other. The pressure balancing mechanism includes at least one port or housing channel 294 that provides pressure communication between at least one seal cavity and an external environment having the same or similar pressure characteristics as the external environment in contact with the seal, such as within the left ventricle. For example, the pressure balancing housing channel 294 may be positioned within 20 mm (e.g., within 15 mm, within 10 mm, within 5 mm) of the axial gap 174 such that both the housing channel 294 and the axial gap 174 are positioned within the left ventricle. A fluid-tight, yet flexible, diaphragm 292 occludes each housing channel 294 to prevent the passage of blood or lubricant, but passively deforms to transmit pressure and reduce the pressure difference between the external blood and the internal lubricant. If the ambient pressure within the heart increases beyond the pressure in the sealing element, the diaphragm 292 will flex inwardly, increasing the pressure inside the sealed cavity and providing a higher resistance to blood ingress. Conversely, if the ambient pressure decreases below the pressure in the sealing element, the diaphragm 292 will flex outwardly, decreasing the pressure inside the sealed cavity and providing less outward force on the greases and lubricants stored therein.

[0100] As shown in FIG. 15, the seal cavity 176a, optionally connected to the second seal cavity 176b, may be filled with grease. One or more seal cavities are in fluid communication with a seal channel 291, which is in fluid communication with a housing channel 294, which is in fluid communication with a diaphragm 292. Alternatively, a disk divider may be positioned between the two seal cavities, with one, preferably the distal seal cavity, in fluid communication with a channel (not shown). The seal channel 291 may be a radial bore or passage in the seal holder or between the two seal holders 166a, 166b. The housing channel 294 may be at least one (e.g., one, two, three, four, five, six) bore through one or more housings containing the seal. For example, the housing channel 294 may pass through the motor housing 164 as shown, or through the seal housing if the seal is held in a container as shown in FIG. 16A. Further, in implementations where the MCS device has an impeller housing or inlet tube 70 positioned on the motor housing 164, the housing channel may extend through a hole 293 through the impeller housing or inlet tube, and a diaphragm 292 may optionally fill the hole 293. Alternatively, the hole 293 may be diaphragm-free and may have a smaller diameter than the hole 292 containing the diaphragm to anchor the diaphragm in place. The diaphragm may be silicone. Optionally, a lubricant reservoir 290 may be in fluid communication with both the seal channel and the housing channel. The lubricant reservoir 290 may be made by machining an annular groove in the motor housing and may function to hold additional lubricant or to evenly distribute pressure around the seal. Optionally, the lubricant reservoir may be filled with a fluid other than grease, such as sterile water with glucose. Optionally, the lubricant has a viscosity in the range of 0.30 to 1.30 mPas.

[0101] The manufacturing method may include dispensing a lubricant through at least one of the housing channels 294 prior to applying the diaphragm. A second housing channel in fluid communication with the seal cavity and the first housing channel may act as a vent to allow air to escape as the lubricant is injected, improving pressure balancing capabilities.

[0102] Optionally, an axially compressible washer such as a wave washer (not shown) may be positioned proximal to proximal seal 167b and rest against a ridge or surface such as a seal canister cap (not shown). The compressible washer may apply an axial force to the proximal seal, increasing pressure within the grease-filled seal cavity or causing the diaphragm to bulge outward slightly when the device is at atmospheric pressure or fluctuates around a relatively neutral position when exposed to blood pressure.

[0103] J. Embodiments Having a Rotary Shaft Seal and an Axial Face Seal with Barrier Fluid 19 shows a schematic diagram of the heart pump 22 according to the design example. The heart pump 22 comprises a housing 164, an impeller 72, a motor 115, a sealing element 300 and a barrier fluid 301. The heart pump 22 represents a blood pump, typically an axial pump, which is driven by the motor 115 in the form of an integrated electric motor, to generate the required blood flow by the impeller 72 when the heart pump 22 is installed inside the patient's body.

[0104] The housing 164 has an interior 302 and an opening 303 to the interior 302. The interior 302 is shaped to accommodate the motor 115. The motor 115 is located within the interior 302 and has a shaft 140. The motor 115 is shaped to drive the shaft 140. The shaft 140 passes through the opening 303 and is coupled to the impeller 72 to drive the impeller 72. The impeller 72 has at least one blade 178, here exemplarily having two blades 178 suitable for pumping blood. The impeller 72 is disposed on a drive shaft 140 extending from the motor housing. The sealing element 300 is located between the impeller 72 and the motor housing 164 and is designed to seal the axial gap 174 between the impeller 72 and the motor housing 164. The sealing element 300 may be attached to the impeller 72. Alternatively, the sealing element 300 is attached to the motor housing 164. The sealing element 300 is ring-shaped to completely seal around the gap 174. The sealing element 300 may be an axial face seal. Optionally, the heart pump 22 has a further sealing element 167, whereby the further sealing element 167 is located in the opening 303 and designed to seal an interior 302 of the motor housing 164 against a space 305 between the motor housing 164 and the impeller 72. In this case, the space 305 is sealed against the environment of the heart pump 22 by the sealing element 300 and against the interior 302 by the further sealing element 167. Optionally, the further sealing element 167 may be in the form of or have other features of other radial rotating shaft sealing elements disclosed elsewhere herein, such as a lip seal or multiple lip seals.

[0105] According to this example, the barrier fluid 301 in the space 305 is held in the space 305 by the sealing elements 300, 174. The barrier fluid 301 prevents media from the environment of the heart pump 22 from penetrating into the interior of the motor 115. If the additional sealing element 167 is omitted, the space 305 is fluidly connected to the interior 302 of the housing 164. In this case, the barrier fluid 301 may extend into the interior of the motor 115. Thus, the motor interior may be filled with the barrier fluid 301.

[0106] The shaft 140 is mounted on the opposite side of the housing 164. For this purpose, two bearings 162 are arranged in the interior 302 as an example supporting the shaft 140. According to one design example, during operation of the heart pump 22, blood, which may also be described as a fluid, is fed axially to the impeller 72, where it is sucked in and expelled radially and diagonally, for example through the openings 68. The impeller 72 is fixed to the shaft 140 of the motor 115, which provides the necessary drive power. According to a design example, the shaft 140 is supported by at least one radial and / or at least one axial bearing 162. Optionally, the bearings 162 may also be used in combination with the radial-axial bearing 162.

[0107] The sealing element 300 can be contact or non-contact, for example as a labyrinth seal or a gap seal, or a combination of both. Furthermore, at least one additional sealing element 167 is optionally provided to seal the shaft 140 against the housing 164. The space between the sealing element 300 and the motor housing 164 is ideally filled with a biocompatible barrier fluid 301, which prevents the pumped medium (blood) from penetrating the interior of the motor throughout the required operating time and the service life of the heart pump 22. Optionally, the additional sealing element 167 reduces leakage of the barrier fluid 301 inside the motor. According to another possible design example, the entire interior of the motor is filled with the barrier fluid 301. The barrier fluid 301 ideally consists of a biocompatible medium, for example glucose or endogenous fats. Furthermore, the viscosity of the fluid is preferably such that it does not cause excessive friction losses and does not evaporate from the space 305 during operation due to its low viscosity. Furthermore, a good compatibility with the motor components must be sought.

[0108] For example, the heart pump 22 can be used as a temporary or short-term ventricular assist device (VAD) or mechanical circulatory support (MCS) pump, which can be implanted very quickly. For this purpose, the heart pump 22 is designed as a simple system according to the design example. The advantage is that the heart pump 22 requires an external energy supply, but does not require an irrigation medium that serves to protect the motor 115 from blood infiltration. The heart pump 22 does not require such an external forced flushing.

[0109] According to one design example, the heart pump 22 essentially consists of an impeller 72 and a sealing element 300, which is rigidly connected to the impeller 72 and has a sealing function against the housing 164 or, alternatively, against a corresponding sealing element rigidly connected to the motor housing 164 and has a sealing function against the impeller 72. Furthermore, the heart pump 22 has an optional sealing element 167 that seals the housing 164 against the rotating shaft 178. A special feature here is that the space 305 between the two sealing elements 300, 167 is filled with a barrier fluid, which prevents the pumped medium (blood) from penetrating into the interior of the motor over the operating period.

[0110] K. Surface Treatment Optionally, a surface treatment may be applied to one or more components to help prevent blood or blood particle clots from sticking to the surface, or to facilitate blood movement, or to reduce friction between the seal lip or disk and the rotating shaft. For example, a surface treatment may be applied to the proximal surface of the impeller, the rotating shaft, the distal surface of the seal receptacle 241. The surface treatment may be a hydrophilic coating, such as polyvinylpyrrolidone (PVP) having a thickness in the range of 3-5 μm, or a hydrophobic coating, such as perfluoroalkoxy (PFA) having a thickness in the range of 10-20 μm. The surface treatment may be a micropatterned surface with hydrophilic or hydrophobic properties. Surface treatments or materials used to fabricate components such as the seal holder 166 may include titanium nitride, ceramic, or ceramic impregnated with PTFE.

[0111] L. Embodiments with Superabsorbents Optionally, the MCS device may include a superabsorbent in the rotating shaft seal assembly, such as those disclosed herein. For example, the superabsorbent material may be provided on a carrier material, such as a foil or a thin strip of cellulose, and positioned in the seal assembly, such as in or in contact with the seal cavity. The carrier (not shown) may be in the form of a disk with a central hole and may be positioned on one or more of the distal side of the middle disk 260, the proximal side of the middle disk 260, or the distal side of the proximal disk 275 of the implementation shown in FIG. 16A. Alternatively or additionally, the superabsorbent may be an encapsulated superabsorbent granulation positioned in the seal cavity, and may optionally be mixed into a grease. The rotating shaft lip seal or other features, such as the leading edge of the seal or disk, may provide a primary barrier against blood ingress, but if some blood does enter the seal, the superabsorbent may absorb the blood and further prevent blood from passing into the motor or clotting between the lip and the rotating shaft. The hydrophilic behavior of the superabsorbent may avoid absorbing oil from grease. When blood is absorbed, the absorbent may increase in volume and exert pressure on the sealing lip to further prevent blood from entering. The superabsorbent may contain a small amount (e.g., <50 microliters) of sodium polyacrylate.

[0112] M. Impeller with proximal vanes The MCS device may have features of the implementations disclosed herein and may optionally further include an impeller 72 having a central impeller hub 146, axial flow blades (e.g., two blades) 178 extending radially from the hub 146, an impeller base 150 at the proximal end of the hub 146 and radial flow blades 177 arranged on a plane perpendicular to the axis of the hub, and a central bore 226 within and coaxial with the hub. Optionally, the impeller may have proximal vanes 177 on a proximal face of the impeller base 150.

[0113] Without being bound by theory, the proximal vanes are structural protrusions, or alternatively indentations, extending radially on the proximal surface of the impeller base that enhance fluid flow in the axial gap 174 as the impeller rotates, which may improve convective heat transport, increasing efficiency and reducing blood cell damage. Heat is generated in the motor and bearings by friction between the seals and the rotating shaft, which may cause blood particles to clot. By removing heat from this area, the risk of blood clotting may be reduced. Small axial gaps are preferred over large gaps, which may cause loss of efficiency and vortex area, which in turn may increase pressure, reduce efficiency, and cause damage to the blood. The proximal vanes allow for very small axial gaps, for example, axial gaps in the range of 0.08 mm to 0.3 mm, while still increasing flow. Additionally, the proximal vanes may increase the radial component of the mixed axial and radial blood flow to move blood out of the exit window 68 or reduce fluid pressure in the axial gap 174, which may improve the function of the seal.

[0114] FIG. 17A shows an isometric schematic of an impeller 72 of an MCS device that does not have proximal vanes, but instead has a smooth proximal surface 225 on the impeller base 150. In contrast, FIGS. 17B and 17C show an impeller with two versions of proximal vanes 177. Preferably, the impeller is balanced about its central axis to rotate smoothly without vibration. To balance the impeller, the proximal vanes 177 can be made to be radially symmetric, for example, at least two proximal vanes on either side of equal weight and shape can provide radial symmetry, three proximal vanes positioned at 120 degrees around the central axis can provide radial symmetry, and four proximal vanes positioned at 90 degrees around the central axis can provide radial symmetry, as shown in FIGS. 17B and 17C. As shown in FIG. 17B, the proximal vanes 177 may lie in a plane parallel to the impeller base 150 and may be curved to promote blood flow radially outward. For example, the curvature of the proximal vanes may be rotationally convex. Alternatively, the proximal vanes may be straight and extend radially from the central bore 226, as shown in FIG. 17C. The proximal vanes may optionally have inner edges that are not connected to each other, as shown in FIG. 17B, or may be connected to each other, as shown in FIG. 17C. The impeller proximal vanes 177 may be made, for example machined or molded, directly on the impeller base 150, as shown in FIG. 18B, or alternatively, may be made on a separate component, such as the impeller base plate 152, that is connected to the impeller, as shown in FIG. 18A.

[0115] N. Embodiments for connecting the impeller to the drive shaft The impeller 72 may be connected to the drive shaft 140 in a robust manner with a consistent axial gap 174 to reduce the risk of contaminating or damaging the rotary shaft seal. In a first exemplary implementation shown in FIG. 9B, the impeller 72 may be connected to the drive shaft 140 by first connecting an impeller base plate 152 to the drive shaft, the base plate having a proximally extending tubular proximal extension 154. This implementation is described in detail above. Optionally, the base plate 152 may have an impeller proximal vane 177 on a proximal face of the base plate 152 facing the axial gap 174.

[0116] In a second exemplary implementation shown in FIG. 18A, the impeller base plate 152 with the tubular extension 154 may be connected to the drive shaft 140 first. In contrast to the implementation of FIG. 9B, the base plate 152 may be oriented with the tubular extension 154 facing distally. Optionally, the tubular extension may have a non-circular cylindrical extension to rotationally lock the impeller to the tubular extension and base plate. The base plate may be connected to the drive shaft 140 by laser welding or adhesive. For example, a laser weld may be applied to the interface between the distal end of the tubular extension 154 and the drive shaft 140 while a spacer is temporarily positioned in the axial gap 174 to ensure consistent gap and linear alignment. The impeller 72 may then be connected to the base plate 152 by inserting the tubular extension 154 into a central bore 266 in the impeller. The impeller 72 may be connected to the drive shaft 140, for example, by dispensing glue into the impeller central bore 226 and sliding the impeller onto the drive shaft, the side bores 227 allowing air or excess glue to optionally escape, and the base plate may have impeller proximal vanes 177 on its proximal face toward the axial gap 174.

[0117] 18B, the impeller 72 may be connected directly to the drive shaft 140, for example, without a base plate. The impeller 72 may be connected to the drive shaft 140, for example, by dispensing glue into the impeller central bore 226 and sliding the impeller onto the drive shaft, with the side bores 227 allowing air or excess glue to escape while ensuring an axial gap 174 of a known distance, for example, by mounting a manufacturing tool or by inserting a spacer into the gap 174.

[0118] In a fourth exemplary implementation shown in FIG. 18C, the impeller 72 and impeller base plate 152 may be connected to the drive shaft 140 with a key 309. The impeller base plate 152 may optionally have a proximally oriented tubular extension and may optionally have an impeller proximal vane 117 oriented proximally in the axial gap 174. The impeller base plate 152 may have a recess 310 that fits closely with the portion of the key 309 extending from the recess 310. The impeller 72 may also have a recess 311 into which the portion of the key 309 extending from the recess 310 may mate. The recess 311 may have additional space to make room for a weld seam on the distal face of the key 309 and around the shaft 140. Because key 309, recess 310, and recess 311 have interlocking shapes and are non-circular in a plane transverse to the axis of rotation, key 309 cannot spin within the recess, but instead transmits rotational force from shaft 140 to impeller base plate 152 and impeller 72 at least partially through key 309. A method of assembly may include assembling a seal (e.g., a seal subassembly such as that shown in FIG. 16A, 16B, or 16C, or another implementation of a seal disclosed herein) over a drive shaft 140 extending from a motor, positioning an impeller base plate 152 having a recess 310 over the drive shaft while maintaining a desired axial gap 174, for example with a temporary spacer, positioning a key 309 over the drive shaft 140 and within the recess 310, laser welding the key 309 to the drive shaft 140 to create a weld seam 312, and positioning an impeller 72 over the assembly such that the drive shaft 140 is inserted into the impeller central bore 226, the key 309 is inserted into the impeller recess 311, and the base of the impeller contacts the impeller base plate 152. The impeller 72 may be laser welded to the base plate 152 to create a weld seam 313. Optionally, adhesive may be added into the central bore 226 of the impeller prior to inserting the drive shaft, in which case side ports 227 may allow excess adhesive or air to escape.Optionally, adhesive may be applied between the impeller 72 and the impeller base plate 152, between the base plate 152 and the shaft 140, or between the key 309 and the impeller or base plate. Optionally, in this implementation, the impeller 72 and the impeller base plate 152 may be made of different materials. In this case, an adhesive may be used to bond them together and the key 309 may be held in the cavity between them and welded to the shaft 140.

[0119] O. Correction Various modifications to the implementations described in this disclosure will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other implementations without departing from the spirit or scope of the present disclosure. Thus, the present disclosure is not intended to be limited to the implementations shown herein, but is to be accorded the widest scope consistent with the claims, principles, and novel features disclosed herein. The word "example" is used herein only to mean "serving as an example, instance, or illustration." Any implementation described herein as "example" should not necessarily be construed as preferred or advantageous over other implementations, unless otherwise specified.

[0120] Certain features that are described in this specification in the context of separate implementations can also be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation can also be implemented in multiple implementations separately or in any suitable subcombination. Moreover, although features may be described above as acting in a particular combination and may originally be claimed as such, one or more features from a claimed combination can, in some cases, be deleted from that combination, and the claimed combination can be directed to a subcombination or a variation of the subcombination.

[0121] Similarly, although operations are illustrated in the figures in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown, or in any sequential order, or that all of the illustrated operations be performed, to achieve desirable results. Moreover, other implementations are within the scope of the following claims. In some cases, the acts recited in the claims may be performed in a different order and still achieve desirable results.

[0122] P.Terms In general, those of skill in the art will understand that the terms used herein are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including but not limited to," "having" should be interpreted as "having at least," "includes" should be interpreted as "including but not limited to," etc.). It will be further understood by those of skill in the art that where specific numerals of introduced claim recitations are intended, such intention will be expressly set forth in the claims, and in the absence of such recitation, no such intention exists. For example, as an aid to understanding, the following appended claims may include the use of the introductory phrases "at least one" and "one or more" to introduce the claim recitations. However, the use of such phrases should not be interpreted as implying that the introduction of a claim recitation with the indefinite article "a" or "an" limits any particular claim that includes such an introduced claim recitation to embodiments that include only one such recitation, even if the same claim includes the introductory phrase "one or more" or "at least one" and an indefinite article such as "a" or "an" (e.g., "a" and / or "an" should typically be interpreted to mean "at least one" or "one or more"). The same applies to the use of definite articles used to introduce claim recitations. Moreover, even if specific numbers in an introduced claim recitation are explicitly recited, one of ordinary skill in the art will recognize that such recitations should typically be interpreted to mean at least the recited numbers (e.g., the mere recitation of "two recitations" without other modifiers typically means at least two recitations, or more than two recitations).Furthermore, when a convention similar to "at least one of A, B, and C, etc." is used, such an interpretation is generally intended in the sense that one of ordinary skill in the art would understand the convention (e.g., "a system having at least one of A, B, and C" includes, but is not limited to, systems having A alone, B alone, C alone, A and B together, A and C together, B and C together, and / or A, B, and C together, etc.). When a convention similar to "at least one of A, B, or C, etc." is used, such an interpretation is generally intended in the sense that one of ordinary skill in the art would understand the convention (e.g., "a system having at least one of A, B, or C" includes, but is not limited to, systems having A alone, B alone, C alone, A and B together, A and C together, B and C together, and / or A, B, and C together, etc.). It will be further understood by those skilled in the art that virtually any disjunction and / or phrase presenting two or more alternative terms in the description, claims, or drawings should be understood to contemplate the possibility of including one of the terms, either of the terms, or both terms. For example, the phrase "A or B" will be understood to include the possibilities of "A" or "B," or "A and B."

[0123] Q. Exemplary Embodiments The following is a non-exhaustive list of numbered exemplary embodiments. 1. A seal for a heart pump, comprising: a distal radial shaft seal configured to surround a motor shaft of the heart pump, the distal radial shaft seal having a flat side facing distally and an open side facing proximally; and a proximal radial shaft seal configured to surround the shaft and be located proximal to the distal radial shaft seal such that the proximal radial shaft seal is located farther from the pump impeller than the distal radial shaft seal and has a flat side of the proximal radial shaft seal facing proximally and an open side of the proximal radial shaft seal facing distally. 2. A seal as described in embodiment 1, wherein the distal radial shaft seal comprises a radially inner lip configured to contact the shaft and extend proximally from the flat side of the distal radial shaft seal. 3. The seal of embodiment 1 or 2, further comprising a distal spring located at least partially within the open side of the distal radial shaft seal and configured to urge the radially inner lip of the distal radial shaft seal radially inwardly onto the shaft. 4. A seal as described in any of embodiments 1-3, further comprising a proximal spring located at least partially within the open side of the proximal radial shaft seal and configured to compress the radially inner lip of the proximal radial shaft seal radially inwardly onto the shaft. 5. The seal of any of embodiments 1-4, further comprising one or more disks with a central opening having an inner diameter configured to be smaller than the outer diameter of the shaft. 6. The seal of embodiment 5, wherein a radially inner edge of the central opening of each of the disks is configured to wear in response to rotation of the shaft. 7. The seal of any of embodiments 1-6, further comprising grease located between the distal radial shaft seal and the intermediate disc, and between the intermediate disc and the proximal radial shaft seal. 8. A seal according to any of embodiments 1-7, wherein the distal radial shaft seal and the proximal radial shaft seal each have a radially outer lip configured to contact the inside of the housing. 9. A seal according to any of the preceding embodiments, wherein the seal is configured to be assembled with a heart pump and delivered to the heart via a catheter. 10. The seal of any of embodiments 1-9, further comprising a housing having a distal end wall and a cylindrical side wall extending proximally from the distal end wall, the distal end wall having a distal side configured to contact the blood flow, and a central opening configured to receive the shaft therethrough, and a distal radial shaft seal configured to be positioned at least partially within the housing, proximal to the distal end wall. 11. A seal for a heart pump, the heart pump having a motor configured to rotate an impeller via a shaft about an axis, the seal comprising: The seal comprises a distal radial shaft seal having a distal side configured to face distally toward the impeller and a radially inner lip configured to contact the shaft and extend proximally from the distal side toward the motor. 12. The seal of embodiment 11, further comprising a proximal radial shaft seal having a proximal side configured to face proximally toward the motor and a radially inner lip configured to contact the shaft and extend distally from the proximal side toward the impeller. 13. The seal of embodiment 11 or 12, further comprising one or more disks having an opening with an inner diameter smaller than the outer diameter of the shaft. 14. A seal as described in any of embodiments 11 to 13, further comprising a seal housing configured to couple with a motor housing configured to assist the motor, and the distal radial shaft seal is at least partially located within the seal housing. 15. The seal of embodiment 14, wherein the distal radial shaft seal and the seal housing are configured to be inserted onto the shaft as an integrated unit. 16. A heart pump comprising: The impeller, a motor configured to rotate the impeller via a shaft about an axis; and a seal comprising a distal radial shaft seal having a distal side configured to face distally toward the impeller and a radially inner lip configured to contact the shaft and extend proximally from the distal side toward the motor. 17. A heart pump as described in embodiment 16, further comprising a proximal radial shaft seal having a proximal side configured to face proximally towards the motor and a radially inner lip configured to contact the shaft and extend distally from the proximal side towards the impeller. 18. A heart pump as described in embodiment 16 or 17, further comprising one or more disks in the housing having an opening with an inner diameter smaller than the outer diameter of the shaft. 19. A heart pump as described in any of embodiments 16 to 18, further comprising a seal housing, the seal and seal housing being configured to be inserted onto the shaft as an integrated unit. 20. A heart pump according to any of embodiments 16 to 19, wherein the heart pump is configured to be delivered to the heart via a catheter. 21. A seal assembly for a heart pump, comprising: a housing having a distal end wall and a cylindrical side wall, the side wall extending axially and proximally from the distal end wall to define a cavity, the distal end wall having a distal side configured to contact the blood flow, and a central opening configured to receive a shaft having an outer diameter therethrough; a distal disc inside the cavity located proximal to the distal end wall; a distal radial shaft seal inside a cavity located proximally of the distal disk, the distal radial shaft seal having a distally facing flat side and a proximally facing open side; a proximal radial shaft seal inside a cavity located proximal to the distal radial shaft seal, the proximal radial shaft seal having a proximally facing flat side and a distally facing open side; an intermediate disk inside a cavity proximal to the distal radial shaft seal and distal to the proximal radial shaft seal. 22. The seal assembly of embodiment 21, further comprising a proximal disk located proximal to the proximal radial shaft seal and configured to be spring loaded when assembled with the heart pump to apply a compressive force in a distal direction on the proximal radial shaft seal. 23. A distal spring located at least partially within the open side of the distal radial shaft seal and configured to urge a radially inner lip of the distal radial shaft seal radially inwardly onto the shaft; 23. The seal assembly of embodiment 21 or 22, further comprising: a proximal spring located at least partially within the open side of the proximal radial shaft seal and configured to urge a radially inner lip of the proximal radial shaft seal radially inwardly onto the shaft. 24. A seal assembly according to any of embodiments 21-23, wherein the distal disc and the intermediate disc each have a central opening having an inner diameter configured to be smaller than the outer diameter of the shaft. 25. The seal assembly of embodiment 24, wherein the radially inner edge of the central opening of each of the distal disc and the intermediate disc is configured to wear in response to rotation of the shaft. 26. The seal assembly of any of embodiments 21-25, further comprising grease positioned between the distal radial shaft seal and the intermediate disc, and between the intermediate disc and the proximal radial shaft seal. 27. A seal assembly according to any of embodiments 21-26, wherein the distal radial shaft seal and the proximal radial shaft seal each have a radially inner lip that contacts the shaft. 28. A seal assembly according to any of embodiments 21-27, wherein the distal radial shaft seal and the proximal radial shaft seal each have a radially outer lip that contacts the housing. 29. A seal assembly as described in any of embodiments 21-28, wherein the seal assembly is configured to be inserted as an integrated unit onto the shaft and at least partially within the heart pump housing. 30. A seal assembly as described in any of embodiments 21-29, wherein the seal assembly is configured to be assembled with a heart pump and delivered to the heart via a catheter. 31. A seal assembly according to any of embodiments 21 to 30, wherein the housing is a seal housing configured to be coupled to a motor housing that complements the motor of a heart pump. 32. A seal assembly according to any of embodiments 21 to 30, wherein the housing is a motor housing configured to assist the motor of a heart pump. 33. A seal assembly for a heart pump, the heart pump having a motor configured to rotate an impeller via a shaft about an axis, the seal assembly comprising: Housing and a distal radial shaft seal within the housing having a flat side configured to face distally toward the impeller and a radially inner lip configured to contact the shaft and extend proximally from the flat side toward the motor. 34. The seal assembly of embodiment 33, further comprising a proximal radial shaft seal in the housing having a flat side configured to face proximally toward the motor and a radially inner lip configured to extend distally from the flat side along the shaft toward the impeller. 35. The seal assembly of embodiment 33 or 34, further comprising one or more disks in the housing having an opening with an inner diameter smaller than the outer diameter of the shaft. 36. The seal assembly of any of embodiments 33-35, wherein the seal assembly is configured to be inserted onto the shaft as an integrated unit. 37. The seal assembly of any of embodiments 33-36, wherein the distal radial shaft seal is elastomeric. 38. A seal assembly according to any of embodiments 33-37, wherein the housing is a seal housing configured to be coupled to a motor housing that complements the motor of a heart pump. 39. A seal assembly according to any of embodiments 33 to 37, wherein the housing is a motor housing configured to assist a motor of a heart pump. 40. A heart pump comprising: The impeller, a motor configured to rotate the impeller via a shaft about an axis; and a seal assembly, the seal assembly comprising: Housing and a distal radial shaft seal within the housing having a flat side configured to face distally toward the impeller and a radially inner lip configured to contact the shaft and extend proximally from the flat side toward the motor. 41. A heart pump as described in embodiment 40, further comprising a proximal radial shaft seal within the housing having a flat side configured to face proximally toward the motor and a radially inner lip configured to contact the shaft and extend distally from the flat side toward the impeller. 42. A heart pump as described in embodiment 40 or 41, further comprising one or more disks in the housing having an opening with an inner diameter smaller than the outer diameter of the shaft. 43. A heart pump as described in any of embodiments 40 to 42, wherein the seal assembly is configured to be inserted as an integrated unit onto the shaft. 44. A heart pump according to any of embodiments 40 to 43, wherein the heart pump is configured to be delivered to the heart via a catheter. 45. A heart pump according to any of embodiments 40 to 44, wherein the housing is a seal housing configured to be coupled with a motor housing that assists the motor. 46. ​​A heart pump according to any of embodiments 40 to 44, wherein the housing is a motor housing configured to assist the motor. 47. A heart pump (22), comprising: a motor (145) having a rotor; an impeller (72) for providing blood flow; a drive shaft (140) connected to the rotor and the impeller; a sealing element (156) disposed between the motor and the impeller; A heart pump (22) wherein a seal element (156) includes a central aperture for receiving a drive shaft (140) in sealing contact. 48. A heart pump (22) as described in embodiment 47, wherein the motor (145) is contained within the motor housing (164) and a portion of the drive shaft (140) extends from the motor housing. 49. A heart pump (22) as described in embodiment 48, wherein a sealing element (156) is arranged between a wall of the motor housing (164) and the drive shaft (140). 50. A heart pump (22) according to any of the preceding embodiments 47-49, wherein the sealing element (156) is positioned at least partially within the motor housing. 51. A heart pump (22) according to any of the preceding embodiments 48 to 50, wherein the sealing element (156) is connected to the motor housing (164). 52. A heart pump (22) according to any of the preceding embodiments 48 to 50, wherein the sealing element (156) is connected to the drive shaft (164). 53. The heart pump (22) according to any of the preceding embodiments 48 to 52, wherein the motor housing has an outer diameter in the range of 4 to 5 mm. 54. The heart pump (22) according to any of the preceding embodiments 48 to 52, wherein the motor housing has an outer diameter of 5 mm or less. 55. The heart pump (22) of any of the preceding embodiments 48 to 54, wherein the motor housing has a length of 33 mm or less, optionally 25.5 mm or less. 56. A heart pump (22) according to any of the preceding embodiments 48 to 55, wherein the seal element (156) is at least partially contained within the seal housing (240). 57. A heart pump (22) as described in embodiment 56, wherein the motor housing (164) is configured to be welded to the seal housing (240). 58. A heart pump (22) as described in embodiment 57, wherein the seal housing (240) has an outer surface recess (245), the motor housing has an inner surface, and the outer surface recess is mated with the inner surface. 59. A heart pump (22) as described in embodiment 57 or 58, wherein the seal housing (240) has an outer surface rabbet (246), the motor housing has an outer surface rabbet (247), and the seal housing is attached to the motor housing (164) by welding where the seal housing rabbet meets the motor housing rabbet. 60. A heart pump (22) according to any of the preceding embodiments 47 to 59, wherein the drive shaft (140), the rotor, the impeller (72), and the sealing element (156) each share a central axis. 61. The heart pump (22) according to any of the preceding embodiments 47 to 59, wherein at least a portion of the drive shaft (140) is flexible. 62. A heart pump (22) according to embodiment 60 or 61, wherein the drive shaft is provided with a sleeve 154. 63. A heart pump (22) according to any of the preceding embodiments 60-62, wherein the drive shaft comprises a surface treatment, optionally comprising electropolishing, nitriding, a hydrophilic coating (optionally polyvinylpyrrolidone having a thickness in the range of 3-5 μm), a hydrophobic coating (optionally perfluoroalkoxy having a thickness in the range of 10-20 μm), or a micropatterned surface. 64. The heart pump (22) according to any of the preceding embodiments 60-63, wherein the drive shaft (140) has a length in the range of 1200 mm to 1500 mm. 65. The heart pump (22) of embodiment 64, wherein the drive shaft (140) has a length in the range of 29 to 34 mm. 66. A heart pump (22) according to any of the preceding embodiments 47 to 65, wherein the impeller (72) is connected to the drive shaft (140) at a proximal end of the impeller. 67. The heart pump (22) of embodiment 66, wherein the distal end of the impeller is freely floating. 68. A heart pump (22) as described in embodiment 66 or 67, wherein the impeller (72) has a central hub (146), the central hub has a central bore (226), and the drive shaft (140) is positioned within the central bore. 69. The heart pump (22) of embodiment 68, wherein the impeller (72) further comprises at least one side bore (227) communicating with the central bore (226). 70. A heart pump (22) as described in embodiment 69, wherein the side bore (227) is distal to the drive shaft (140). 71. A heart pump (22) according to any of the preceding embodiments 68-70, wherein an impeller base plate (152) is connected to the drive shaft (140) and the impeller (72). 72. A heart pump (22) as described in embodiment 71, wherein at least a portion of the impeller base plate (152) is positioned between the drive shaft (140) and the central bore (226). 73. A heart pump (22) according to embodiment 71, wherein the impeller base plate (152) comprises a tubular extension (154) that is part of the drive shaft. 74. A heart pump (22) according to any of the preceding embodiments 47 to 73, wherein the impeller has a base flange (150). 75. The heart pump (22) according to embodiment 74 in combination with embodiment 68, wherein the central hub (146) transitions to the base flange (150) with a smooth concave curve or taper. 76. The heart pump (22) according to embodiment 74 combined with embodiment 48, wherein the base flange has a diameter between 0 mm and 0.1 mm smaller than the outer diameter of the motor housing (164). 77. A heart pump (22) according to any of the preceding embodiments 47 to 76, wherein the impeller (72) comprises radial flow blades (177) arranged in a plane perpendicular to the impeller's axis of rotation. 78. A heart pump (22) according to embodiment 77 combined with embodiment 74, wherein the radial flow blades (177) are on a proximal surface of the impeller base flange (150). 79. A heart pump (22) according to embodiment 77 combined with embodiment 71, wherein the radial flow blades (177) are on the proximal surface of the impeller base plate (152). 80. A heart pump (22) according to any of the preceding embodiments 77-79, wherein the radial flow blades (177) are protrusions or recesses extending radially from the axis of rotation of the impeller (72). 81. The heart pump (22) of any of the preceding embodiments 77-80, wherein the radial flow blades (177) are one of straight or curved. 82. A heart pump (22) as described in any of the preceding embodiments 77 to 81, wherein the sealing element (156) and the radial flow blade (177) are separated by an axial gap (174), the axial gap having a distance in the range of 0.08 mm to 0.3 mm. 83. A heart pump (22) according to any of the preceding embodiments 77 to 82, wherein the radial flow blades (177) are arranged radially symmetrically about the axis of rotation of the impeller (72). 84. A heart pump (22) according to any of the preceding embodiments 77 to 83, wherein the radial flow blades (177) include a surface treatment, optionally comprising electropolishing, nitriding, a hydrophilic coating (optionally polyvinylpyrrolidone having a thickness in the range of 3 to 5 μm), a hydrophobic coating (optionally perfluoroalkoxy having a thickness in the range of 10 to 20 μm), or a micropatterned surface. 85. A heart pump (22) as described in any of the preceding embodiments 47 to 84, wherein the sealing element (156) comprises a rotary shaft lip seal having a seal holder (166), an elastomeric annular seal (167), a seal cavity (176), and a garter spring (168) positioned within the seal cavity, the elastomeric annular seal (167) comprising a contact lip (169). 86. A heart pump (22) as described in embodiment 85 combined with embodiment 2, wherein the seal holder (166) is configured to remain stationary relative to the motor housing (164) and the contact lip (169) is configured to contact the drive shaft (140). 87. A heart pump (22) as described in embodiment 85 combined with embodiment 2, wherein the seal holder (166) is configured to remain stationary relative to the drive shaft (140) and the contact lip (169) is configured to contact the motor housing (164). 88. A heart pump (22) according to any of the preceding embodiments 85 to 87, wherein the seal cavity (176) is at least partially defined by the seal holder (166) and the elastomeric annular seal (167). 89. The heart pump (22) according to any of the preceding embodiments 85 to 88, wherein the first grease (175) is disposed within the seal cavity (176). 90. The heart pump (22) according to any of the preceding embodiments 85 to 89, wherein the seal cavity (176) is oriented distally. 91. The heart pump (22) according to any of the preceding embodiments 85 to 89, wherein the seal cavity (176) is oriented proximally. 92. The heart pump (22) according to any of the preceding embodiments 85 to 91, further comprising a distal disc (255) located distal to the sealing element (156). 93. A heart pump (22) according to embodiment 92, wherein the distal disc (255) has a distal surface configured to contact blood in use. 94. The heart pump (22) according to any of the preceding embodiments 92 or 93, wherein the distal disc (255) is at least partially made of stainless steel, titanium, PTFE, PEEK, or polyurethane. 95. A heart pump (22) according to any of the preceding embodiments 92 to 94, wherein the distal disc (255) has a central opening having an inner diameter larger than the outer diameter of the drive shaft (140), optionally by a difference in the range of 0.02 to 0.1 mm. 96. A heart pump (22) according to any of the preceding embodiments 92 to 94, wherein the distal disc (255) has a central opening having an inner diameter smaller than the outer diameter of the drive shaft (140), optionally by a difference in the range of 0.02 to 0.1 mm. 97. A heart pump (22) according to any of the preceding embodiments 92 to 96, wherein the distal disc (255) has a thickness (172) that is uniform and in the range of 0.1 mm to 1.5 mm, optionally about 1.0 mm. 98. A heart pump (22) according to any of the preceding embodiments 92-97 in combination with embodiment 48, wherein the distal disk (255) is provided with a form-fitting mechanism (173) configured to provide a tight connection to the motor housing (164). 99. A heart pump (22) according to any of the preceding embodiments 92 to 98, wherein at least a distal surface of the distal disc (255) comprises a surface treatment, optionally comprising electropolishing, nitriding, a hydrophilic coating (optionally polyvinylpyrrolidone having a thickness in the range of 3 to 5 μm), a hydrophobic coating (optionally perfluoroalkoxy having a thickness in the range of 10 to 20 μm), or a micropatterned surface. 100. The heart pump (22) of any of the preceding embodiments 85-99, further comprising a proximal disc (275) located adjacent and proximal to the sealing element (156). 101. A heart pump (22) according to embodiment 100, wherein the proximal disc (275) is at least partially made of stainless steel, titanium, PTFE, PEEK, or polyurethane. 102. A heart pump (22) as described in the preceding embodiment 100 or 101, wherein the proximal disc (275) has a central opening having an inner diameter larger than the outer diameter of the drive shaft (140), optionally by a difference in the range of 0.02 to 0.1 mm. 103. A heart pump (22) according to any of the preceding embodiments 100 or 101, wherein the proximal disc (275) has a central opening having an inner diameter smaller than the outer diameter of the drive shaft (140), optionally by a difference in the range of 0.02 to 0.1 mm. 104. The heart pump (22) according to any of the preceding embodiments 100-103, wherein the proximal disc (275) is uniform and has a thickness in the range of 0.1 mm to 1.5 mm, optionally about 1.0 mm. 105. A heart pump (22) according to any of the preceding embodiments 100-104 in combination with embodiment 48, wherein the proximal disc (275) is provided with a form-fitting mechanism configured to provide a tight connection to the motor housing (164). 106. The heart pump (22) according to any of the preceding embodiments 100-105, wherein the proximal disc is axially spring loaded. 107. A heart pump (22) as described in any of the preceding embodiments 100 to 105, wherein the proximal cavity (189) is at least partially defined by the proximal disc (275) and the sealing element (156), and a second grease is located within the proximal cavity (189). 108. The heart pump (22) of embodiment 107, wherein the second grease has a lower consistency than the first grease. 109. A heart pump (22) according to embodiment 90 or 91, further comprising a distal protective disk (212), the distal protective disk (212) comprising a central opening (213) and a distally facing conical surface (214) having a concave contour. 110. A heart pump (22) as described in embodiment 109, wherein at least a portion of the central opening (213) has a diameter larger than the outer diameter of the drive shaft (140), optionally by a difference in the range of 0.08 to 0.15 mm. 111. A heart pump (22) as described in embodiment 110, wherein at least a portion of the central opening (213) has a diameter smaller than the outer diameter of the drive shaft (140), optionally by a difference in the range of 0.01 to 0.05 mm. 112. The heart pump (22) according to any of the preceding embodiments 109-111 in combination with embodiment 2, wherein the distal protective disk (212) is connected to the motor housing (164). 113. A heart pump (22) according to any of the preceding embodiments 109 to 112, wherein the distal protective disk (212) is made of an elastomeric material, optionally PTFE or PEEK. 114. The heart pump (22) according to any of the preceding embodiments 109-113 in combination with embodiment 21, wherein the conical surface (214) is aligned with a surface of the hub (146). 115. A heart pump (22) as described in any of the preceding embodiments 109 to 114 in combination with embodiment 21, wherein the distal protective disk (212) has a flat surface portion (215) adjacent to the conical surface (214), the hub (146) has a flat base, and the flat surface portion (215) has a diameter within 0.01 mm of the diameter of the flat base. 116. A heart pump (22) according to any of the preceding embodiments 109 to 115, wherein the impeller (72) comprises an overlapping impeller (210) having at least two impeller blades (178), each of the at least two impeller blades (178) having a proximal portion (211) shaped to conform to a conical surface (214). 117. A heart pump (22) as described in any of the preceding embodiments 109 to 115, wherein the impeller (72) has at least two impeller blades (178), each of the at least two impeller blades (178) having a proximal portion (211) having a flat edge (225). 118. A heart pump (22) as described in any of the preceding embodiments 85 to 117, wherein the sealing element (156) further comprises a second rotating shaft lip seal having a second seal holder (166b), a second elastomeric annular seal (167b), and a second seal cavity (176b), and the second elastomeric annular seal (167b) comprises a second contact lip (169b). 119. The heart pump (22) of embodiment 118, further comprising a second garter spring (168b) positioned within the second seal cavity (176b). 120. The heart pump (22) according to any of the preceding embodiments 118 or 119, wherein the second seal cavity (176b) is oriented towards the first seal cavity (176, 176a). 121. A heart pump (22) according to any of the preceding embodiments 118-120, wherein the contact lip (169, 169a) and the second contact lip (169b) are oriented towards each other. 122. The heart pump (22) of any of the preceding embodiments 118-121 in combination with embodiment 89, wherein the first grease is disposed in the second seal cavity (176b). 123. A heart pump (22) as described in any of the preceding embodiments 118-121 combined with embodiment 89, wherein a third grease is disposed in the second seal cavity (176b), and the third grease has properties different from the first grease. 124. A heart pump (22) according to any of the preceding embodiments 118 to 123, further comprising an intermediate disc (260) axially positioned between the rotary shaft lip seal and the second rotary shaft lip seal. 125. The heart pump (22) according to embodiment 124, wherein the intermediate disc (260) is made of an elastomeric material, optionally PTFE or PEEK. 126. A heart pump (22) as described in the preceding embodiment 124 or 125, wherein the intermediate disc (260) has a central opening, at least a portion of which has a diameter (261) smaller than the outer diameter of the drive shaft (140), optionally by a difference in the range of 0.01 to 0.05 mm. 127. The heart pump (22) according to any of the preceding embodiments 124 or 125 in combination with embodiment 123, wherein the third grease and the first grease are separated by an intermediate disc (260). 128. A heart pump (22) as described in any of the preceding embodiments 118 to 127, wherein at least one of the elastomeric annular seal (167, 167a) and the second elastomeric annular seal (167b) has a leading edge, the leading edge having a central hole smaller than the outer diameter of the drive shaft (140). 129. A heart pump (22) as described in embodiment 128, wherein the leading edge central hole is within the range of 80% to 90% of the outer diameter of the drive shaft (140). 130. The heart pump (22) according to any of the previous embodiments 128 or 129, wherein the leading edge is located distal to the contact lip (169) and the second contact lip (169b). 131. A heart pump (22) as described in any of the preceding embodiments 47 to 130, further comprising an axial face lip seal (300) positioned proximal to the impeller (72), the axial face lip seal (300) comprising a lip configured to slidably contact the proximal end of the impeller. 132. A heart pump (22) as described in embodiment 131 combined with embodiment 85, wherein the fluid barrier reservoir is defined by an axial surface lip seal (300), a base of the impeller (72), and a rotary shaft lip seal, and fluid is deposited within the fluid barrier reservoir. 133. A heart pump (22) according to any of the preceding embodiments 47 to 132, wherein the seal element (156) is at least partially contained within the seal housing (240). 134. A heart pump (22) as described in embodiment 133, wherein the seal housing (240) has a distal end wall and a cylindrical side wall, the side wall extending axially and proximally from the distal end wall to define a cavity (248), the distal end wall having a distal side (241) configured to contact the blood flow, and a central opening (242) configured to receive a shaft (140) having an outer diameter (141) therethrough. 135. A heart pump (22) according to embodiment 134, wherein the distal side (241) is a smooth, flat surface. 136. The heart pump (22) according to any of the preceding embodiments 134 or 135, wherein the distal side (241) comprises a surface treatment, optionally comprising electropolishing, nitriding, a hydrophilic coating (optionally polyvinylpyrrolidone having a thickness in the range of 3-5 μm), a hydrophobic coating (optionally perfluoroalkoxy having a thickness in the range of 10-20 μm), or a micropatterned surface. 137. A heart pump (22) according to any of the preceding embodiments 133 to 136, further comprising a seal container cap (278) connected to the seal housing (240) and configured to contain a seal element (156). 138. A heart pump (22) as described in embodiment 137, wherein the seal housing (240) and the seal container cap (278) both have a central opening having an inner diameter larger than the outer diameter (141) of the drive shaft (140), optionally by a difference in the range of 0.08 to 0.15 mm. 139. A heart pump (22) according to any of the preceding embodiments 133-138 in combination with embodiment 2, wherein the seal housing (240) is configured to be at least partially inserted within the motor housing (164). 140. A heart pump (22) as described in any of the preceding embodiments 47 to 139, further comprising a pressure balancing element in fluid communication with the sealing element (156), the pressure balancing element responding in use to changes in blood pressure within the patient's heart. 141. Pressure balancing elements: a channel between the seal cavity (176, 176a) and the environment external to the heart pump (22); The heart pump (22) according to embodiment 140 in combination with embodiment 85, comprising a diaphragm covering the channel. 142. The heart pump (22) according to any one of the preceding embodiments 140 or 141, wherein the pressure balancing element further comprises a lubricant reservoir (290). 143. The heart pump (22) according to embodiment 142 combined with embodiment 2, wherein the lubricant reservoir (290) is a recess in the motor housing (164). 144. The heart pump (22) according to embodiment 142 or 143 combined with embodiment 2, wherein the lubricant reservoir (290) is an annular groove in the inner surface of the motor housing (164). 145. A heart pump (22) according to any of the preceding embodiments 140 to 144, wherein a lubricant is deposited within the pressure balancing element. 146. A heart pump (22) according to any of the preceding embodiments 142-145, wherein the lubricant is deposited in the lubricant reservoir (290). 147. The heart pump (22) according to embodiment 145 or 146, wherein the lubricant has a viscosity in the range of 0.30 to 1.30 mPa.s. 148. A heart pump (22) according to any of the preceding embodiments 141 to 147, wherein the channel comprises at least one of a seal holder channel (291), a seal housing channel, a motor housing channel (294), or an inlet tube channel (293). 149. A heart pump (22) according to any of the preceding embodiments 141-148 in combination with embodiment 118, wherein the channel is in fluid communication with the second seal cavity (176b). 150. The heart pump (22) of any of the preceding embodiments 141-149 in combination with embodiment 35, wherein the environment outside the heart pump is within 20 mm of the axial gap (174). 151. The heart pump (22) according to any of the preceding embodiments 141-150, wherein the environment external to the heart pump is within the left ventricle of the patient. 152. The heart pump (22) according to any of the preceding embodiments 141 to 151, wherein the diaphragm (292) is made of silicone. 153. The heart pump (22) according to any of the preceding embodiments 141-152, wherein the diaphragm (292) is positioned at a radially outer portion of the channel. 154. A heart pump (22) according to any of the preceding embodiments 141 to 153, comprising an inlet tube (70) having a pressure balancing port (293) having a diameter smaller than the diameter of the diaphragm (202), and the diaphragm (292) is positioned radially below the part (293). 155. A heart pump (22) according to any of the preceding embodiments 141-154, wherein the channel comprises a plurality of radially extending channels. 156. The heart pump (22) according to any of the preceding embodiments 47 to 155, further comprising a superabsorbent positioned within the sealing element (156). 157. The heart pump (22) according to embodiment 156, wherein the superabsorbent is supported on a piece of foil or cellulose. 158. A heart pump (22) as described in the preceding embodiment 156 or 157, wherein a superabsorbent is positioned in at least one of the seal cavity (176a), the second seal cavity (176b), on the distal disc (255), on the middle disc (260), on the proximal disc (275), on the grease (175), on the second grease, or on the third grease. 159. The heart pump (22) according to any of the preceding embodiments 156 to 158, wherein the superabsorbent comprises sodium polyacrylate. 160. A heart pump (22) as described in any of the preceding embodiments 47 to 159, wherein the impeller (72) is connected to an impeller base plate (152), and the impeller base plate (152) is connected to the drive shaft (140). 161. A heart pump (22) according to embodiment 160, wherein the impeller base plate (152) comprises a tubular extension (154). 162. A heart pump (22) as described in embodiment 161, wherein the tubular extension (154) is positioned at least partially within the central bore (226) of the impeller (72). 163. The heart pump (22) according to embodiment 161, wherein the tubular extension (154) is at least partially positioned within the sealing element (156). 164. A heart pump (22) as described in any of the preceding embodiments 160 to 163, wherein the impeller (72) has a recess (311), the impeller base plate (152) has a recess (310), and the key (309) is positioned within the recess (311) and the recess (310). 165. A heart pump (22) according to embodiment 164, wherein the key (309) is welded to the drive shaft (140). 166. The heart pump (22) according to any of the preceding embodiments 164 or 165, wherein the key (309) is non-circular in plant transverse to the axis of rotation of the impeller (72). 167. A heart pump (22) according to any of the preceding embodiments 160-166, wherein the impeller (72) is welded to the impeller base plate (152). 168. The heart pump (22) according to any of the preceding embodiments 160 to 166, wherein the impeller (72) and the impeller base plate (152) are made of different materials. 169. A heart pump (22) according to any of the preceding embodiments 47 to 168, wherein the sealing element is configured to maintain functionality for at least 12 hours. 170. A heart pump (22) according to any of the preceding embodiments 47 to 168, wherein the sealing element is configured to lose functionality due to wear after 12 hours. 171. A controller for providing power to a motor of a heart pump, the controller comprising a control algorithm, the motor being a field oriented controlled motor, the control algorithm adjusting the power based on a feedback signal from the field oriented controlled motor to maintain the motor within a rotational speed set point range. 172. The controller of embodiment 171, wherein the rotational speed set point range is ±1% of the rotational speed. 173. A system comprising a heart pump (22) as described in any of the preceding embodiments 47 to 168 and a controller as described in embodiment 171 or 172. 174. A heart pump (22) characterized in that: a housing (164) having an interior (302) and an opening (303) to the interior (302); an impeller (72) having at least one blade (178), the impeller (72) being positioned proximate to the opening (303); a motor (115) disposed within the interior (302) and having a shaft (140) passing through the opening (303) and coupled to the impeller (72) for driving the impeller (72); a sealing element (300) disposed between the impeller (72) and the housing (164) and adapted to seal a gap (174) between the impeller (72) and the housing (164); A heart pump (22) having a barrier fluid (301) disposed between the seal member (300) and the shaft (140) and adapted to prevent ingress of a medium from the environment of the heart pump (22) into the interior of the motor (115). 175. A heart pump (22) according to embodiment 174, wherein the sealing element (300) is attached to the impeller (72). 176. A heart pump (22) according to embodiment 174, wherein the sealing element (300) is attached to the housing (164). 177. A heart pump (22) according to any of the preceding embodiments, further comprising a barrier fluid (301) contained within the motor (115). 178. The heart pump (22) according to any one of the preceding embodiments, wherein the sealing element (300) is formed as a contact seal or a contactless seal. 179. The heart pump (22) according to one of the previous embodiments, wherein the sealing element (300) is designed as a labyrinth seal and / or a gap seal. 180. A heart pump (22) according to any one of the preceding embodiments, comprising a further sealing element (167), the further sealing element (167) being disposed in the opening (303) and configured to seal an interior space (302) of the housing (164) against fluid located between the housing (164) and the impeller (72), and a barrier fluid (301) being disposed in the space (305). 181. A heart pump (22) according to any one of the preceding embodiments, comprising at least one bearing (162), the bearing (162) being designed to house the shaft (140) relative to the housing (164). 182. The heart pump (22) according to any one of the preceding embodiments, wherein the barrier fluid (301) is a biocompatible medium. 183. The heart pump (22) according to any one of the preceding embodiments, wherein the barrier fluid (301) consists of glucose and / or endogenous fat. 184. The heart pump (22) according to any one of the preceding embodiments in combination with embodiment 100, wherein the proximal sealing disc (275) is provided with an axial face seal on its proximal side slidably engaged with the bearing. 185. The heart pump (22) according to any one of the preceding embodiments in combination with embodiment 56, wherein the seal housing (240) has a distally facing conical surface 321. 186. A heart pump (22) as described in embodiment 185, wherein the distal disk (255) comprises a tubular extension (322) having a radially inward surface, at least a portion of the radially inward surface contacting the motor shaft (140). 187. A heart pump (22) as described in embodiment 186, wherein the tubular extension (322) has a surface texture or treatment on its radially inward surface, the surface texture or treatment optionally including circumferential ribs, dimples, a hydrophilic micropattern, or a hydrophobic micropattern. 188. The heart pump (22) according to embodiment 186, wherein the tubular extension is made of a biocompatible elastomer. 189. A heart pump (22) as described in embodiment 186, wherein the tubular extension is made of an elastomer or thermoplastic material, and a cavity is adjacent to the tubular extension, optionally within the seal housing (240), and the cavity is configured to hold a lubricant and deliver the lubricant to the tubular extension. 190. A heart pump (22) according to any of embodiments 184 to 189, wherein the tubular extension has a distal surface (323) that is flush with the distal end of the seal housing (240). 191. A heart pump (22) according to any of embodiments 184 to 189, wherein the tubular extension has a distal surface (323) extending distally beyond the seal housing (240), optionally in the range of 0 to 200 microns, preferably about 100 microns. 192. The heart pump (22) according to embodiment 191, wherein the distal surface (323) is an axial face seal in slidable contact with the impeller (72). 193. The heart pump (22) according to any one of embodiments 185 to 192, further comprising an outlet strut auxiliary (325). 194. A heart pump (22) as described in embodiment 193, wherein each of the outlet strut auxiliary bodies is connected to the outlet strut (195) at a position at least between the proximal end and the distal end of the outlet strut (195). 195. A heart pump (22) as described in embodiment 194, wherein the outlet strut auxiliary (325) is connected to or is part of the seal housing (240), optionally the distally facing conical surface (321). 196. A heart pump (22) as described in embodiment 195, wherein the outlet strut auxiliary (325) has an axial length (326) that is a portion of the outlet strut length, optionally the portion being up to 30%, up to 50%, or up to 100% of the outlet strut length. 197. A heart pump (22) as described in embodiment 195, wherein the outlet strut auxiliary (325) has an axial length (326) that is a portion of the axial length of the conical surface (321), optionally the portion being up to 30%, up to 50%, or up to 100% of the axial length of the conical surface. 198. A heart pump (22) according to any of embodiments 193 to 197, wherein the outlet strut auxiliary (325) has a rounded leading edge (328). 199. A heart pump (22) according to embodiment 198, wherein the outlet strut auxiliary (325) comprises an angled surface from the leading edge (328) to the adjacent outlet window (68). 200. A heart pump (22) according to embodiment 198 or 199, wherein the leading edge (328) is centered within the width of the connecting outlet post (195). 201. A heart pump (22) as described in embodiment 198 or 199, wherein the leading edge (328) is positioned within the width of the connecting outlet strut (195) and near or adjacent to the edge of the connecting outlet strut (195) on the side facing the radial component of the blood flow. 202. A heart pump (22) as described in any one of the preceding embodiments combined with embodiment 100, wherein the proximal sealing disc (275) has a first thickness (282) and a second thickness (283) that is thicker than the first thickness (282) and closer to the central axis (185) than the first thickness (282). 203. The heart pump (22) according to embodiment 202 in combination with embodiment 137, wherein the second thickness (283) is greater than the combination of the first thickness (282) and the thickness of the sealed container cap (278).

Claims

1. 1. A heart pump comprising: a motor having a rotor; an impeller for providing blood flow; a drive shaft connected to the rotor and the impeller; a seal disposed between the motor and the impeller, The seal is a distal radial shaft seal surrounding the drive shaft of the heart pump, the distal radial shaft seal having a flat side facing distally and an open side facing proximally; a proximal radial shaft seal, the proximal radial shaft seal being located further from the impeller of the heart pump than the distal radial shaft seal, the proximal radial shaft seal surrounding the drive shaft and located proximal to the distal radial shaft seal such that the proximal radial shaft seal has a flat side facing proximally and an open side facing distally; one or more disks having a central opening with an inner diameter configured to be smaller than an outer diameter of the drive shaft; grease located between the distal radial shaft seal and the proximal radial shaft seal.

2. 2. The heart pump of claim 1, wherein the distal radial shaft seal comprises a radially inner lip configured to contact the drive shaft and extend proximally from the flat side of the distal radial shaft seal, and the proximal radial shaft seal comprises a radially inner lip configured to contact the drive shaft and extend distally from the flat side of the proximal radial shaft seal.

3. 2. The heart pump of claim 1, further comprising: a distal spring located at least partially within the open side of the distal radial shaft seal and configured to compress a radially inner lip of the distal radial shaft seal radially inward onto the drive shaft; and a proximal spring located at least partially within the open side of the proximal radial shaft seal and configured to compress a radially inner lip of the proximal radial shaft seal radially inward onto the shaft.

4. 10. The heart pump of claim 1, wherein a radially inner edge of the central opening of each of the one or more disks is configured to wear in response to rotation of the shaft.

5. A heart pump as described in claim 4, wherein the grease is located between the distal radial shaft seal and the intermediate disc, and between the intermediate disc and the proximal radial shaft seal.

6. The heart pump of any one of claims 1 to 3, wherein the seal is configured to be assembled with the heart pump and delivered to the heart via a catheter.

7. 4. The heart pump of claim 1, further comprising a housing having a distal end wall and a cylindrical side wall extending proximally from the distal end wall, the distal end wall having a distal side configured to contact blood flow and a central opening configured to receive the drive shaft therethrough, the distal radial shaft seal configured to be located at least partially within the housing proximal to the distal end wall.

8. 2. The heart pump of claim 1, wherein the motor is enclosed within a motor housing, and a portion of the drive shaft extends from the motor housing.

9. The heart pump of claim 8 , wherein the seal is disposed between a wall of the motor housing and the drive shaft.

10. 10. The heart pump of claim 8 or 9, wherein the seal is positioned at least partially within the motor housing.

11. 10. The heart pump of claim 8 or 9, wherein the motor housing has a length of 33 mm or less, optionally 25.5 mm or less.

12. 10. The heart pump of claim 8 or 9, wherein the seal is at least partially contained within a seal housing.

13. 13. The heart pump of claim 12, wherein the seal housing includes an outer surface recess and the motor housing has an inner surface, the outer surface recess mating with the inner surface.

14. 10. The heart pump of claim 1, wherein the impeller comprises radial flow blades arranged in a plane perpendicular to the axis of rotation of the impeller.

15. 15. The pump of claim 14, wherein the impeller has a base flange and the radial flow blades are on a proximal surface of the impeller base flange.

16. A heart pump as described in claim 1, wherein the one or more discs include an intermediate disc between the proximal radial shaft seal and the distal radial shaft seal.

17. A heart pump as described in claim 1, wherein the one or more discs include a proximal disc proximal to the proximal radial shaft seal.

18. A heart pump as described in claim 1, wherein each of the distal radial shaft seal and the proximal radial shaft seal has a radial inner lip that contacts the drive shaft.

19. A heart pump as described in claim 9, wherein each of the distal radial shaft seal and the proximal radial shaft seal has a radial outer lip that contacts the housing.

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