Rotor bearing systems and methods for mechanical circulatory support systems

Abstract

A rotor bearing system for a minimally invasive miniaturized percutaneous mechanical circulatory support system. The rotor bearing system comprises a cone with a cone-like recess and a bearing component such as a ball or pin rotatably mounted within the cone-like recess of the cone. The cone may be fixedly mounted to a housing comprising a drive comprising a first magnet, and the bearing component may interact with a rotor comprising a second magnet that magnetically cooperates with the first magnet.

Description

ROTOR BEARING SYSTEMS AND METHODS FOR MECHANICALCIRCULATORY SUPPORT SYSTEMSINCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 608718, filed December 11, 2023, and titled “ROTOR BEARING SYSTEMS AND METHODS FOR MECHANICAL CIRCULATORY SUPPORT SYSTEMS”. This application is hereby incorporated by reference herein in its entirety.BACKGROUNDField

[0002] The technology relates generally to cardiac support systems, and in particular to a rotor bearing system for a mechanical circulatory support system.Description of the Related Art

[0003] Mechanical circulatory support systems are used to assist with pumping blood. Such pumping may be useful in various contexts. For example, percutaneous coronary intervention (PCI) is a non-surgical procedure to revascularize stenotic coronary arteries. PCI includes a variety of techniques, e.g. balloon angioplasty, stent implantation, rotablation and lithotripsy. A PCI is considered high risk if either the patient has relevant comorbidities (e.g. frailty or advanced age), the PCI per se is very complex (e.g. bifurcation or total occlusions) or hemodynamic status is challenging (e.g. impaired ventricular function). Mechanical circulatory support systems may be used to assist with pumping blood during this and other procedures. Conventional systems are complex, difficult to use, and have short lifespans that provide only temporary mechanical circulatory support.

[0004] There remains a need for an extended-life mechanical circulatory support system with reduced wear, reduced friction, and improved energy efficiency that lowers adverse events associated with high-risk PCI procedures and overcomes other drawbacks.SUMMARY

[0005] The embodiments disclosed herein each have several aspects no single one of which is solely responsible for the disclosure’s desirable attributes. Without limiting the scope of this disclosure, its more prominent features will now be briefly discussed. After considering this discussion, and particularly after reading the section entitled “Detailed Description,” one will understand how the features of the embodiments described herein provide advantages over existing systems, devices and methods for circulatory support systems.

[0006] In one aspect, a minimally invasive miniaturized percutaneous mechanical circulatory support system is provided. The system may be placed across the aortic valve via a single femoral arterial access point. The system includes a low-profile axial rotary blood pump carried by the distal end of an eight French catheter. The system can be percutaneously inserted through the femoral artery and positioned across the aortic valve into the left ventricle. The device actively unloads the left ventricle by pumping blood from the left ventricle into the ascending aorta and systemic circulation. The mechanical circulatory support system may include any of the rotor bearing systems described herein, such as the ball and cone bearing systems, e.g. between a drive housing and a rotating rotor.

[0007] In another aspect, a mechanical circulatory support system for high risk coronary interventions and use thereafter may be provided. The system may include an elongate flexible catheter shaft, having a proximal end and a distal end, a circulatory support device carried by the distal end of the shaft, the circulatory support device including a tubular housing, having a proximal end and a distal end, and an impeller within the housing. The system may include a removable guidewire guide tube entering a first guidewire port on a distal end of the housing, exiting the housing via a second guidewire port on a side wall of the housing distal to the impeller, reentering the housing via a third guidewire port on a proximal side of the impeller, and extending proximally into the catheter shaft. The circulatory support device may include any of the rotor bearing systems described herein. For example, the system may include a motor within the housing and configured to rotate the impeller in a contactless manner. The motor may be positioned distal to the third guidewire port. The tubular housing may have an axial length in a range of 60 mm to 100 mm. The system may include a blood exit port on the tubular housing in communication with the impeller, and a blood inlet portspaced distally apart from the blood exit port. The housing may include a flexible slotted tube covered by an outer polymeric sleeve, an inner polymeric sleeve, or both and inner and an outer polymeric sleeve. The system may include a sealed motor housing inside of the tubular housing. The mechanical circulatory support system may include any of the rotor bearing systems described herein, such as the ball and cone bearing systems, e.g. between a drive housing and a rotating rotor.

[0008] In another aspect, a mechanical circulatory support system for high risk coronary interventions and support use thereafter may be provided. The system may include a circulatory support catheter, including a circulatory support device carried by an elongate flexible catheter shaft, an insertion tool having a tubular body and configured to axially movably receive the circulatory support device, and an access sheath, having a tubular body and configured to axially movably receive the insertion tool. The access sheath may include an access sheath hub having an insertion tool lock for engaging the insertion tool. The access sheath hub may include a catheter shaft lock for locking the access sheath hub to the catheter shaft. The mechanical circulatory support system may include any of the rotor bearing systems described herein, such as the ball and cone bearing systems, e.g. between a drive housing and a rotating rotor.

[0009] In another aspect, a mechanical circulatory support system having a rotor bearing system used for the contactless transmission of a torque to a rotating rotor of the mechanical circulatory support system is provided. The mechanical circulatory support system may include a rotor comprising a first magnet. The mechanical circulatory support system may include a drive with a first magnet and a housing in which the drive is located. The mechanical circulatory support system may also include a rotor comprising a second magnet. The first magnet of the drive and the second magnet of the rotor may interact. The rotor bearing system of the mechanical circulatory support system may comprise a cone with a cone-like recess, the cone being connected to or contacting the housing, and a ball connected to or contacting the rotor and rotatably mounted in the cone-like recess of the cone. The rotor bearing system may be included in any of the circulatory support systems described herein.

[0010] There may be various embodiments of the above or other aspects herein. For example, in some embodiments, the drive can be realized as an electric motor. The first and second magnets may work together to drive the rotor using a magnetic field. The blademay mobilize a patient’s body fluid, such as blood, and may allow for support of the patient’s cardiac function.

[0011] In some embodiments, the rotor may comprise a plurality of blades. One or more blades and / or a cylindrical extension of the rotor may comprise a second magnet. In some embodiments, the rotor may comprise a recess designed to receive the ball of the rotor bearing system.

[0012] In some embodiments, the ball of the rotor bearing system may be round in shape in order to evenly absorb forces acting on the ball element, for example, axial and / or radial forces. In some embodiments, the ball of the rotor bearing system may have a ball radius between about 0.2 mm and about 0.7 mm. Friction on the ball surface can be influenced by selecting a suitable ball radius.

[0013] In some embodiments, the cone of the rotor bearing system may have a cone-like recess with a cone angle between about 70 degrees and about 110 degrees. If the cone angle is as large as possible, wear on the ball mounted within the cone-like recess and / or wear within the cone-like recess of the cone element can be reduced.

[0014] In some embodiments, the ball of the rotor bearing system may comprise a radius of about 0.3 mm and the cone-like recess of the cone of the rotor bearing system may comprise a cone angle of about 100 degrees. These dimensions may provide for a rotor bearing system with enhanced friction and wear properties.

[0015] In some embodiments, the cone of the rotor bearing system may comprise a cylindrically shaped component having the cone-like recess at an end thereof. A cylindrical shape cone may serve as a base and act as an interface between the ball, the rotor, and the housing of the mechanical circulatory support system. In some embodiments, the housing may comprise a recess to accommodate the cone.

[0016] In some embodiments, the cone and the ball of the rotor bearing system may form a pivot bearing. The pivot bearing may serve as an interface between the rotor and the housing of the drive of the mechanical circulatory support system. The ball may be fixed to the rotor and may rotate at the same speed as the rotor.

[0017] In some embodiments, the mechanical circulatory support system may comprise a rotor bearing system and a hydrodynamic radial slide bearing. The hydrodynamic radial slide bearing may be arranged at an end or distal tip of the rotor facing away from thedrive. In some embodiments, the hydrodynamic radial slide bearing may be arranged at a rotor end opposite the rotor bearing system. The hydrodynamic radial slide bearing may stabilize the rotor and enable the patient’s blood to be pumped evenly through the mechanical circulatory support system. The rotor may comprise a recess adapted to receive the ball. The housing may comprise a recess adapted to receive the cone.

[0018] In another aspect, any of the mechanical circulatory support systems described herein may include the ball and / or cone that comprises sapphire.

[0019] In another aspect, any of the mechanical circulatory support systems described herein may include the second magnet driven by rotation of the first magnet to cause the rotor to rotate.

[0020] In another aspect, a mechanical circulatory support system includes a motor, a drive, a rotor and a bearing. The drive is configured to be rotated about an axis by the motor via a shaft and comprises a first magnet, the first magnet at least partially encased in a housing. The rotor comprises an impeller and a second magnet, the second magnet surrounding the housing and in magnetic communication with the first magnet such that rotation of the drive causes the impeller to rotate. The bearing is rotationally coupling a distal-facing face of the housing and a proximal-facing face of the rotor.

[0021] In some embodiments, the first and second magnets may be axially offset and overlapping. The first and second magnets may not overlap. The bearing may further comprise a cone having a cone-like recess, the cone being fixedly connected to or contacting the housing of the drive, and a ball connected to or contacting the rotor and rotatably mounted in the cone-like recess of the cone. The ball may have a radius R between about 0.2 mm and about 0.7 mm. The cone-like recess of the cone may have an angle between about 70 degrees and about 110 degrees. The cone may be cylindrically shaped. The cone and the ball may form a pivot bearing. The pivot bearing may include the cone mounted in a recess on an end of the rotor facing the drive. The mechanical circulatory support system may further comprise a hydrodynamic radial slide bearing arranged on a tip of the rotor facing away from the drive. The rotor may comprise a recess adapted to receive the ball. The housing may comprise a recess adapted to receive the cone. The ball and / or cone may comprise sapphire.

[0022] In some examples, the mechanical circulatory support system described herein can include a drive including a first magnet; a housing at least partially surrounding thedrive; a rotor including a blade and a second magnet, wherein the second magnet is magnetically coupled with the first magnet; a cup on the housing, the cup including a conical recess; and a ball contacting the rotor and the conical recess of the cup, the ball configured to rotate in the conical recess. In some examples, the ball has a radius of between about 0.2 mm and about 0.7 mm. In some examples, a profile of the conical recess of the cup has an angle of between about 70 degrees and about 110 degrees. In some examples, the cup includes a cylinder with the conical recess on a circular face of the cylinder. In some examples, the ball is positioned on an end of the rotor facing the drive. In some aspects, the techniques described herein relate to a system, further including a hydrodynamic radial slide bearing positioned on a distal tip of the rotor facing away from the drive. In some examples, the rotor includes a recess configured to receive the ball. In some examples, the housing includes a recess configured to receive the cup. In some examples, at least one of the ball or the cup include sapphire. In some examples, the second magnet is configured to cause the rotor to rotate when the first magnet rotates.

[0023] In some examples, the mechanical circulatory support system described herein can include a drive including: a motor configured to rotate a shaft; and a first magnet configured to be rotated by the shaft, the first magnet at least partially surrounded by a housing; a rotor including an impeller and a second magnet, the second magnet at least partially surrounding the housing, the second magnet magnetically coupled with the first magnet such that rotation of the shaft causes the impeller to rotate; and a bearing disposed between a distal face of the housing and a proximal face of the rotor, the bearing configured to allow the rotor to rotate relative to the housing.

[0024] In some examples, the first magnet and the second magnet are offset along a longitudinal axis and overlapping along a lateral axis. In some examples, the first magnet and the second magnet are offset along a longitudinal axis and a lateral axis. In some examples, the bearing can include a cup including a conical recess, the cup being fixed to the housing of the drive; and a ball contacting the rotor and rotatably mounted in the conical recess of the cup. In some examples, the ball has a radius between about 0.2 mm and about 0.7 mm. In some examples, a profile of the conical recess of the cup has an angle between about 70 degrees and about 110 degrees. In some examples, the cup includes a cylinder with the conical recess on a circular face of the cylinder. In some aspects, the techniques described herein relate to a system,further including a hydrodynamic radial slide bearing positioned on an end of the rotor facing away from the drive. In some examples, the rotor includes a recess adapted to receive the ball. In some examples, the housing includes a recess adapted to receive the cup. In some examples, the bearing includes sapphire.

[0025] In some aspects, the techniques described herein relate to a system, the bearing further including: a bearing surface including a recess on a distal end of the housing; and a cylindrical bearing pin extending from the impeller, the bearing pin having a proximal end positioned within the recess of the bearing surface.

[0026] In some examples, the bearing surface includes a jewel bearing. In some examples, the recess in the bearing surface is conical. In some examples, the proximal end of the bearing pin is round. In some examples, the system can include an inlet tube configured to carry blood therethrough due to rotation of the rotor; and a delivery catheter configured to deliver the rotor to a heart of a patient.

[0027] Any of the mechanical circulatory support systems described herein may further comprise an inlet tube configured to convey blood therethrough due to rotation of the rotor and a delivery catheter configured to carry the rotor for endovascular delivery of the rotor to the heart of a patient.BRIEF DESCRIPTION OF THE DRAWINGS

[0028] 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. Understanding that these drawings depict only several embodiments in accordance with the disclosure and are not to be considered limiting of its scope, the disclosure will be described with additional specificity and detail through use of the accompanying drawings. In the following detailed description, reference is made to the accompanying drawings, which form a part hereof. In the drawings, similar symbols typically identify similar components, unless context dictates otherwise. The illustrative embodiments described in the detailed description, drawings, and claims are not meant 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 here. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the drawing,can be arranged, substituted, combined, and designed in a wide variety of different configurations, all of which are explicitly contemplated and make part of this disclosure.

[0029] Figure 1 is a cross-sectional view of a distal end of a mechanical circulatory support (MCS) system supported by a catheter and positioned across an aortic valve according to some embodiments.

[0030] Figure 2 schematically illustrates an MCS system inserted into the body via the access pathway from the femoral artery to the left ventricle according to some embodiments.

[0031] Figure 3 is a side elevational view of an embodiment of an MCS system that may incorporate the various features described herein.

[0032] Figure 4 shows the system of Figure 3 with the introducer sheath removed and includes an insertion tool and a guidewire back loading aid according to some embodiments.

[0033] Figure 5 is a side view of an embodiment of an introducer kit, having a sheath and dilator, and that may be used with the various MCS systems and methods described herein.

[0034] Figure 6 shows an embodiment of a placement guidewire that may be used with the various MCS systems and methods described herein.

[0035] Figure 7 is a perspective fragmentary view of a distal pump region of the MCS system shown in Figure 1 according to some embodiments.

[0036] Figure 8 is a side elevational view of a distal region of the MCS system shown in Figure 1, showing the guidewire path and the guidewire back loading aid in place according to some embodiments.

[0037] Figure 9 is a cross-sectional view of a pump having a rotor bearing system according to some embodiments.

[0038] Figure 10 is a cross-sectional view through an embodiment of a rotor bearing system at a position in which a first magnet, which is mounted in a housing, and a second magnet, which is disposed in a rotor, overlap.

[0039] Figure 11 is a cross-sectional view of a pump having a rotor bearing system according to some embodiments having a ball and cone forming a rotational coupling between the rotor and housing.

[0040] Figure 12 is a cross-sectional view of a pump having a rotor bearing system according to some embodiments having a journal and shell rotational coupling.

[0041] Figure 13 is a cross-sectional view of a pump having a rotor bearing system according to some embodiments having a ball and cone rotational coupling and depicting hydrodynamic and magnetic forces on the rotational coupling.

[0042] Figure 14 is a cross-sectional view of an isolated rotor bearing system according to some embodiments having a ball and cone.

[0043] Figure 15 shows a schematic of a rotor bearing system and geometric parameters thereof according to some embodiments.

[0044] Figure 16 shows a plot of friction power as a function of cone angle according to some embodiments of the ball and cone rotor bearing.

[0045] Figure 17 shows a plot of wear as a function of time for balls of various radii according to some embodiments of the ball and cone.

[0046] Figure 18 shows a plot of wear as a function of time for various cone angles according to some embodiments of the ball and cone coupling.

[0047] Figure 19 shows a plot of stress as a function of ball radius according to some embodiments of the ball and cone coupling.

[0048] Figure 20 shows a plot of stress as a function of cone angle according to some embodiments of the ball and cone coupling.

[0049] Figure 21 shows a plot of the ratio of axial stress to radial stress on a rotor bearing as a function cone angle according to some embodiments of the ball and cone coupling.

[0050] Figure 22 shows a cross-sectional view of a rotor bearing system with a pin and cone configuration according to some embodiments.

[0051] Figure 23 shows a cross section through the impeller with a bearing system, magnet coupling, and inlet tube of a microaxial pump according to some embodiments.

[0052] Figure 24 shows a perspective view of the distal region of the impeller having a star bearing in accordance with some embodiments.

[0053] Figure 25 shows a perspective view of a single-piece impeller cage with integrated star bearing according to some embodiments.

[0054] While the above-identified drawings set forth presently disclosed embodiments, other embodiments are also contemplated, as noted in the detailed description.This disclosure presents illustrative embodiments by way of representation and not limitation. Numerous other modifications and embodiments can be devised by those skilled in the art which fall within the scope and spirit of the principles of the presently disclosed embodiments.DETAILED DESCRIPTION

[0055] The following detailed description is directed to certain specific embodiments of the development. In this description, reference is made to the drawings wherein like parts or steps may be designated with like numerals throughout for clarity. Reference in this specification to “one embodiment,” “an embodiment,” or “in some embodiments” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of the phrases “one embodiment,” “an embodiment,” or “in some embodiments” in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments necessarily mutually exclusive of other embodiments. Moreover, various features are described which may be exhibited by some embodiments and not by others. Similarly, various requirements are described which may be requirements for some embodiments but may not be requirements for other embodiments. Reference will now be made in detail to embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

[0056] The mechanical circulatory support (MCS) systems as described herein, for example with respect to Figures 1 -8, may include any of the rotor bearing features as described herein, for example with respect to Figures 9-21. The MCS systems may include a temporary (generally no more than about 6 hours, or no more than about 3 hours, 4 hours, 5 hours, 7 hours, 8 hours, or 9 hours) left ventricular support device for use during various procedures, such as high-risk percutaneous coronary intervention (PCI) performed in elective or urgent, hemodynamically stable patients with severe coronary artery disease and / or depressed left ventricular ejection fraction. The system may be used if a heart team, including a cardiac surgeon, has determined high risk PCI is the appropriate therapeutic option. Alternatively, the MCS systems as described herein may include a long-term left ventricular support device for use during and / or after high-risk PCI performed in elective or urgent, hemodynamically stablepatients with severe coronary artery disease and / or depressed left ventricular ejection fraction, when a heart team, including a cardiac surgeon, has determined high risk PCI is the appropriate therapeutic option. Alternatively, the MCS systems as described herein may include a longterm left ventricular support device for use in patients when a health care provider has determined it is an appropriate therapeutic option. The embodiments of MCS systems and devices as described herein may be placed across the aortic valve, for example, via a single femoral arterial access.

[0057] The system 10 may include a low- profile axial rotary blood pump mounted on a catheter such as an 8 French (Fr) catheter, referred to as an MCS pump or MCS device. When in place, the MCS pump can be driven by an MCS controller to provide up to about 4.0 liters / minute of partial left ventricular support, at about 60 mm Hg. No system purging is needed due to improved bearing design and sealed motor, and the system is visualized fluoroscopically eliminating the need for placement using sensors. The pump may include the rotor bearing systems described herein.

[0058] The system may further include an expandable sheath, which allows 8 - 10 Fr initial access size for easy insertion and closing, expandable to allow introduction of 14 Fr and 18 Fr pump devices and return to a narrower diameter around the 8 Fr catheter once the pump has passed. This feature may allow passage of the heart pump through vasculature while minimizing shear force within the blood vessel, advantageously reducing risk of bleeding and healing complications. Distention or stretching of an arteriotomy may be done with radial stretching with minimal shear, which is less harmful to the vessel. Access may be accomplished via transfemoral, transaxillary, transaortal, or transapical approach.

[0059] Figure 1 shows a distal end of an embodiment of an MCS system 10 having a pump 22 mounted on the tip of an 8 Fr catheter 16. An inlet tube portion 70 of the device extends across the aortic valve 91. An impeller is located at the outflow section of the inlet tube drawing blood from the left ventricle 93 through the inlet tube portion 70 and ejecting it out the outflow section 68 into the ascending aorta 95. The motor is mounted directly proximal to the impeller in a sealed housing eliminating the need to flush the motor prior to or during use. This configuration provides hemodynamic support during high-risk PCI, time and safety for a complete revascularization via a minimally invasive approach (rather than an open surgical procedure).

[0060] The system has been designed to eliminate the need for motor flushing, and provide increased flow performance up to 4.0 1 / min at 60 mmHg with acceptably safe hemolysis due to a computational fluid dynamics (CFD) optimized impeller that minimizes shear stress.

[0061] In some examples, the MCS device actively unloads the left ventricle by pumping blood from the ventricle into the ascending aorta and systemic circulation (shown in Figures 1 and 2). When in place, the MCS device can be driven by a complementary MCS Controller to provide between 0.4 1 / min up to 4.0 1 / min of partial left ventricular support.

[0062] In general, the overall MCS system 10 may include a series of related subsystems and accessories, including one or more of the following:• The MCS Device may include a pump, shaft, proximal hub, insertion tool, proximal cable, infection shield and guidewire aid. For embodiments wherein the MCS Device is left in the body, the system may additionally include a connecting device for detaching and / or attaching the MCS pump and / or inlet device. The MCS Device may be provided sterile;• The MCS shaft may contain the electrical cables and a guidewire lumen for over-the-wire insertion. The MCS shaft may also include a connecting device;• The proximal hub may contain a guidewire outlet with a valve to maintain hemostasis and connects the MCS shaft to the proximal cable, that connects the MCS Device to the MCS Controller;• The proximal cable may be 3.5 m (approx. 177 inch) in length and extend from the sterile field to the non-sterile field where the MCS Controller is located;• An MCS insertion tool may be part of the MCS Device to facilitate the insertion of the pump into an Introducer Sheath and to protect the inlet tube and the valves from potential damage or interference when passing through the Introducer Sheath;• A peel-away guidewire aid may be pre-mounted on the MCS Device to facilitate the insertion of the 0.018” placement guidewire into the pump and into the MCS shaft;• A 3 m long 0.018” diameter placement guidewire may be used, having a soft coiled pre-shaped tip for atraumatic wire placement into the left ventricle. The guidewire may be provided sterile;• A 14 Fr Introducer Sheath with a usable length of 275 mm may be used to maintain access into the femoral artery and provide hemostasis for the 0.035” guidewire, the diagnostic catheters, the 0.018” placement guidewire, and the insertion tool. The housing of the Introducer Sheath may be designed to accommodate the MCS Insertion Tool. The Introducer Sheath may be provided sterile;• An introducer dilator may be compatible with the Introducer Sheath to facilitate atraumatic insertion of the Introducer Sheath into the femoral artery. The introducer dilator may be provided sterile; and / or• An MCS Controller may drive and / or operate the MCS Device, observe its performance and condition as well as provide error and status information. The powered controller may be designed to support at least about 12 hours of continuous operation or may be configured for long-term use and may contain a basic interface to indicate and adjust the level of support provided to the patient. Moreover, the controller may provide an optical and audible alarm notification in case the system detects an error during operation. The MCS Controller may be provided non-sterile and may be contained in an enclosure designed for cleaning and re-use outside of the sterile field. The controller enclosure may contain a socket into which the extension cable is plugged.

[0063] Referring to Figure 3, there is illustrated an example of an overall MCS system 10 in accordance with some embodiments, subcomponents of which will be described in greater detail below. The system 10 may include 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 may extend between a proximal hub 18 and a distal end 20. The hub 18 may be provided with an integrated Microcontroller or memory storage device for device identification and tracking of the running time, which could be used to prevent overuse to avoid excessive wear or other technical malfunction. The microcontroller or memory device could disable the device, for example to prevent using a used device. The microcontroller or memory devicecould communicate with the controller, which could display information about the device or messages about its usage. An atraumatic cannula tip with radiopaque material allows the implantation / explanation to be visible under fluoroscopy.

[0064] A pump 22 may be carried 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 guide wire 24. The proximal hub 18 is additionally provided with an infection shield 26. A proximal cable 28 may extend between the proximal hub 18 and a connector 30 for releasable connection to a control system, typically outside of the sterile field, to drive the pump 22. The pump 22 may include the various rotor bearing systems and features described herein, for example with respect to Figures 9-21.

[0065] Referring to Figure 4, the system 10 may additionally include an insertion tool 32, having an elongate tubular body 36 having a length within the range of from about 85 mm to about 160 mm (e.g., about 114 mm) and an inside diameter within the range of from 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 pump 22 there through, and sufficient collapse resistance to maintain patency when passed through the hemostatic valves of the introducer sheath. As illustrated in Figure 4, the pump 22 can be positioned within the tubular body 36, such as to facilitate passage of the pump 22 through the hemostatic valve(s) on the proximal end of an introducer hub 14. A marker 37 (Figure 7) is provided on the shaft 16 spaced proximally from the distal tip 64 such that as long as the marker 37 is visible on the proximal side of the hub 34, the clinician knows that the pump is within the tubular body 36.

[0066] The hub 34 may be provided with a first engagement structure 39 for engaging a complimentary second engagement structure on the introducer sheath to lock the insertion tool into 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 once the MCS device has been positioned at the desired location in the heart. The hub 34 may additionally be provided with a hemostasis valve to seal around the shaft 16 and also accommodate passage of the larger diameter MCS device which includes the pump. In an example of a commercial presentation of the system, the MCS deviceas packaged is pre-positioned within the insertion tool and the guidewire aid is pre-loaded within the MCS device and shaft 16, as illustrated in Figure 4.

[0067] A guidewire aid 38 (also illustrated in Figure 8) may include a proximal opening 90 configured to slip over and removably receive the distal tip 64 and / or struts at the distal end of the inlet tube 70 that define windows of the pump inlet 66. A guidewire guide tube 83 having a lumen therethrough may be positioned within the proximal opening 90 and aligned to pass through the guidewire port 76 of the distal tip 64. The lumen of the guidewire guide tube 83 may be in communication with a distal flared funnel opening 92 which gets larger in cross-section in the distal direction. The guidewire aid 38 may be provided assembled on the MCS pump with the guidewire guide tube 83 pre-loaded along a guidewire path, for example into the MCS pump through port 76, through a portion of the fluid path within the inlet tube 70, out of the MCS pump through port 78, along the exterior of the MCS pump and back into the shaft 16 through port 80. This helps a user guide the proximal end of a guide wire into the funnel 92 through the guidewire path and into the guidewire lumen of the MCS shaft 16. A pull tab 94 may be provided on the guide wire aid 38 to facilitate grasping and removing the guidewire aid, including the guidewire guide tube 83, following loading of the guidewire. The guidewire aid 38 may have a longitudinal slit or tear line, for example along the funnel 92, proximal opening 90 and guidewire guide tube 83, to facilitate removal of the guidewire aid 38 from the MCS pump 22 and guidewire 100.

[0068] Referring to Figures 5 and 6, an introducer kit 110 may include a guidewire 100, an introducer sheath 112, a dilator 114, and a guidewire aid 38, discussed above. The guidewire 100 may comprise an elongate flexible body 101 extending between a proximal end 102 and a distal end 104. A distal zone of the body 101 may be pre-shaped into a J tip or a pigtail, as illustrated in Figure 6, to provide an atraumatic distal tip. A proximal zone 106 may be configured to facilitate threading through the MCS device and can extend between the proximal end 102 and a transition 108. The proximal zone 106 may have an axial length within the range of from about 100 mm to about 500 mm (e.g., about 300 mm).

[0069] The introducer kit 110 may comprise a sheath 112 and a dilator 114. The sheath 112 may comprise an elongate tubular body 116, extending between a proximal end 118 and a distal end 120. The tubular body 116 may terminate proximally in a proximal hub 122. The tubular body 116 may be expandable or may be configured to be peeled apart. Theproximal hub 122 may include a proximal end port 124 in communication with a central lumen extending throughout the length of the tubular body 116 and out through a distal opening, configured for axially removably receiving the elongate dilator 114. Proximal hub 122 may additionally be provided with a side port 126, at least one and optionally two or more attachment features such as an eye 128 to facilitate suturing to the patient, and at least one and optionally a plurality of hemostasis valves for providing a seal around a variety of introduced components such as a standard 0.035” guidewire, a 5 Fr or 6 Fr diagnostic catheter, an 0.018” placement guidewire 100, and the insertion tool 32.

[0070] Additional details of the distal, pump region of the MCS system according to some embodiments are illustrated in Figure 7. Pump zone 60 may extend between a bend relief 62 at the distal end of shaft 16 and a distal tip 64. A pump inlet 66 may be in fluid communication with a pump outlet 68 by way of a flow path extending axially through an inlet tube 70. The pump inlet may be positioned at about the transition between the inlet tube and the proximal end of distal tip 64, and in any event is generally within about 5 cm or 3 cm or less from a distal port 76. In some embodiments, the distal tip 64 is radiopaque. For example, the distal tip may be made from a polymer containing a radiopacifier such as barium sulfate, bismuth, tungsten, iodine. In some embodiments, an entirety of the 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. Inlet tube 70 may comprise a highly flexible slotted (e.g., laser cut) metal (e.g., Nitinol) tube having a polymeric (e.g., Polyurethane) tubular layer to isolate the flow path. Inlet tube 70 may have an axial length within the range of from about 60 mm and about 100 mm and in one implementation is about 67.5 mm. The outside diameter may be within the range of from about 4 mm to about 5.4 mm, and in one implementation is about 4.66 mm. The wall thickness may be within the range of from about 0.05 mm to about 0.15 mm. The connections between the inlet tube and the distal tip and to the motor may be secured such as through the use of laser welding, adhesives, threaded or other interference fit engagement structures, a releasable connection, or may be via press fit.

[0071] The impeller 72 may be positioned in the flow path between the pump inlet 66 and pump outlet 68. In the illustrated embodiment, the impeller 72 is positioned adjacent tothe pump outlet 68. As is discussed further below, the impeller 72 may be magnetically driven by a motor contained within motor housing 74, on the proximal side of the impeller 72.

[0072] The MCS device may be provided in either a rapid exchange or over the wire configuration. A first guide wire port 76 is in communication, via a first guide wire lumen through the distal tip component 64 and at least a portion of the flow path in the inlet tube, with second guide wire port 78 extending through a side wall of the inlet tube 70, and distal to the impeller 72. This could be used for rapid exchange, with the guidewire extending proximally alongside the catheter from the second guidewire port 78.

[0073] The catheter may be provided in an over the wire configuration, in which the guidewire extends proximally throughout the length of the catheter through a guidewire lumen. In the over the wire embodiment of Figure 7, however, the guidewire exits the catheter via second guidewire port 78, extends proximally across the outside of the impeller and motor housing, and reenters the catheter shaft 16 via third guidewire port 80. See also Figure 8. The third guide wire port 80 may be located proximal to the motor, and, in the illustrated embodiment, is located on the bend relief 62. Third guide wire port 80 is in communication with a guide wire lumen which extends proximally throughout the length of the shaft 16 and exits at a proximal guidewire port carried by the proximal hub 18.

[0074] In some embodiments, a connecting device (not shown in Figure 7) may be located proximal to the motor 74, allowing the MCS system distal of the connecting device to be separated from the MCS shaft 16 and left in the body. Upon completion of treatment, an MCS system may be reconnected via the connecting device for removal, recharging, maintenance, and / or other actions. In some embodiments, a connecting device may be located proximal to the impeller 72 and serve as a connection between the motor 74 and MCS system components distal to the motor 74. In some embodiments, a connecting device may be located distal to the impeller 72 and serve as a connection between inlet tube 70 and MCS system components proximal to the inlet tube 70. In some embodiments, one or more connecting devices may be used to connect various components of the MCS system.

[0075] The pump may be provided assembled with a removable guidewire aid 38 having a guidewire guide tube 83 which tracks the intended path of the guidewire from the first guidewire port 76, proximally through the tip 64 and back outside of the inlet tube via second guide wire port 78 and back into the catheter via third guidewire port 80. In theillustrated implementation, the guidewire guide tube extends proximally within the catheter to a proximal end 81, in communication with, or within the guidewire lumen which 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 into the catheter shaft guidewire lumen for at least about 10 mm or 20 mm, such as within the range of from about 10 mm to about 50 mm. The proximal end of a guidewire 102 may be inserted into the funnel 92, passing through the first (distal) guidewire port 76 and guided along the intended path by tracking inside of the guidewire guide tube. The guidewire guide tube may then be removed, leaving the guidewire in place.

[0076] In some embodiments, the distal end of the guidewire guide tube 83 is attached to the pull tab 94 of guide wire aid 38 and provided with an axially extending split line such as a weakening, slot or perforated tearable line. Removal may be accomplished such as by grasping the pull tab 94 and pulling out the guide wire tube as it splits and peels away along the split line. The inside surface of guide tube 83 may be provided with a lubricious coating, such as PTFE.

[0077] Referring to Figure 9, a cross-sectional view is shown of an example of a pump having the rotor bearing system 1. The system 1 has a contactless torque transmission and a radial and axial bearing of a rotor. The rotor is designed in the form of a pump for cardiovascular support (VAD), for example, such as for a mechanical circulatory support system as described herein.

[0078] The rotor bearing system 1 may comprise a housing 380, here a motor housing, in which a first magnet 330 is seated and mounted on a shaft 406 driven by a not depicted motor such that it can rotate about a first axis 405. The housing 380 may have an outer diameter of about 3.5 mm. The first magnet 330 may comprise a cylindrical permanent magnet.

[0079] The rotor bearing system 1 may further comprise a rotor 370 for conveying a liquid, e.g. blood, wherein the rotor 370 comprises a second magnet 340, which is likewise mounted such that it can rotate with the rotor 370 about the first axis 405. The second magnet 340 may comprise a hollow-cylindrical permanent magnet. The second magnet 340 may be mounted in a hollow-cylindrical part 372 of the rotor 370. The second magnet 340 may comprise a magnetic return 350 on its outer side.

[0080] The first magnet 330 may have an outer diameter of about 3 mm, a magnet height of about 1mm and a length of about 5 mm. The second magnet 340 may have an outer diameter of about 5 mm, a magnet height of about 0.5 mm and a length of about 5 mm. The rotor 370 may have an outer diameter of about 5.3 mm and a length of about 15 mm.

[0081] The rotor 370 may be designed as, or include, an impeller having blades, which converts the mechanical power transmitted by the coupling into hydraulic power for supporting a blood flow against a blood pressure.

[0082] The rotor 370 may further comprise a conical or tapered part 371, which may adjoin the hollow-cylindrical part 372. The outer circumference of the base of the conical part 371 may be connected to the annular opening at an axial end of the hollow-cylindrical part 372.

[0083] The first magnet 330 and the second magnet 340 may overlap axially at least partially in the axial region identified with the reference sign 460. The first magnet 330 may be disposed axially offset relative to the second magnet 340 as shown in Figure 9. The centers of the first magnet 330 and the second magnet 340 are marked by vertical lines and the length of the axial offset 450 distance is identified in between these two vertical lines. In some embodiments, the axial offset 450 may be in the range of from about 0.1 mm to about 1 mm, for example, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, or 0.9 mm. The first magnet 330 may be offset from the second magnet 340 in a proximal direction as shown, or in some embodiments in a distal direction.

[0084] In some examples, as a result of the axial offset 450, the second magnet 340 experiences a force which, in Figure 9, is directed proximally or toward the right as oriented, so that a ball 470 or other bearing component disposed in the rotor 370 is pressed in a cone component or cone 480 mounted in the housing 380, so that a first bearing 320 and a third bearing 390, which here form a combined axial and radial bearing 490, is kept in contact. During proper use, the ball 470 rotates in the cone 480, as a result of which both radial and axial forces can be absorbed. The combined axial and radial bearing 490 here is a solid-body bearing. The ball 470 is disposed in the conical part 371. The axial and radial bearing function is achieved by combining the two elements ball 470 and cone 480.

[0085] In some embodiments, ball 470 may have a diameter of about 0.5 mm. In some embodiments, ball 470 may have a diameter of about 0.6 mm. In some embodiments,ball 470 may have a diameter between about 0.4 mm and about 1.4 mm. In some embodiments, the cone 480 may have a diameter of about 1mm, a height of about 0.8 mm and a cone angle of about 90 degrees. In some embodiments, the cone 480 may have a diameter of about 1mm, a height of about 0.8 mm and a cone angle of about 100 degrees. In some embodiments, the cone 480 may have a cone angle between about 70 degrees and about 110 degrees.

[0086] The axial bearing function of the combined bearing 490 functions as the first bearing and is used for the relative axial positioning of the rotor 370 and the housing 380 or the shaft 406 relative to one another, and also for absorbing an axial force resulting from the arrangement of the first magnet 330 and the second magnet 340. The axial force in the rotor bearing system 1 can furthermore be freely adjusted, as a result of which the acting forces can be optimally adjusted.

[0087] In the overlap region 460 and in the region between the overlap region 460 and the rotor 370, the housing 380, which may comprise the first magnet 330, may be surrounded by the rotor 370, in particular by the interior of the hollow-cylindrical part 372 of the rotor 370. A hollow-cylindrical channel 374 through which the body fluid, for example blood, can flow is thus formed between the housing 380 and the rotor 370. In order to allow the body fluid to flow continuously from outside the conical part 371 of the rotor 370 into the channel 374, bores 200 may be drilled into the rotor 370, preferably in the conical part 371 of the rotor 370, or at a transition from the conical part 371 to the hollow-cylindrical part 372 of the rotor 370. The flow direction of the body fluid is indicated by arrow 410. Arrow 411 indicates a direction of flow of body fluid, e.g. blood, through the channel 374.

[0088] A second bearing 310, which may be designed as a radial, hydrodynamic and blood-lubricated sliding bearing, may be mounted on the end of the conical part 371 of the rotor 370 facing away from the housing 380. The second bearing 310 may be used to absorb radial forces and to position the axis of the rotation of the second magnet 340, which may be disposed in the rotor 370. The second bearing 310 may be disposed between the rotor 370 and an insert 210 which may be mounted, in particular clamped or press-fitted, on a second bearing housing 220 in an annular end, which may in turn be mounted on the housing 380. The second housing 220 may form an outer skin of the rotor bearing system 1 , whereby numerous outlet windows 222 may be present in the second housing 220, which can also be referred to as an impeller housing. The insert 210 is preferably a spider bearing that can be glued, welded orpress-fitted into the second housing 220. The insert 210 may have an outer diameter of about 6 mm and a length of about 3 mm. The second housing 220 may have an outer diameter of about 6 mm, a length of about 18 mm and a wall thickness of about 0.25 mm. The bearing 310 may have a diameter of about 1 mm and a length of about 1 mm.

[0089] As a result of the axial offset 450 between the first magnet 330 and the second magnet 340 in some embodiments, as shown in Figure 9, a defined axial force acts on the rotor 370 in the direction of the motor, i.e., proximally or from left to right as oriented in the embodiment shown in Figure 9. This force is counteracted by a hydraulic force on the rotor 370, i.e., distally or from right to left as oriented in the embodiment shown in Figure 9. In the present case, the axial force originating from the coupling of the first magnet 330 and the second magnet 340 may be selected to be slightly greater than the hydraulic force. On the one hand, this ensures that the rotor 370 is always in a defined axial position and, on the other hand, that the combined axial and radial bearing 490 is not unnecessarily loaded. Consequently, friction and wear are kept low. To optimize the friction and wear behavior, the cone angle of the cone 480 can also be increased, whereby a sufficient radial load-bearing capacity has to be ensured.

[0090] Referring to Figure 10, a cross-sectional view is shown of a rotor bearing system 1 at a position in which the first magnet 330, which may be mounted in the housing 380, and the second magnet 340, which may be disposed in the hollow-cylindrical part 372 of the rotor 370, overlap axially according to some embodiments. It can be seen that the first magnet 330 is seated on the shaft 406 which may be driven by the motor and is mounted such that it can rotate about the first axis 405. It can also be seen that the second magnet 340 is likewise mounted such that it can rotate about the first axis 405. Both the first magnet 330 and the second magnet 340 may comprise two pole pairs, i.e., four poles 202 each, which are respectively radially magnetized in directions as indicated by the arrows in Figure 10.

[0091] Referring to Figure 11, a cross-sectional view is shown of an embodiment of a rotor bearing system 1 similar to the embodiment shown in Figure 9. The present embodiment differs from the embodiment of Figure 9 in that the first magnet 330, the second magnet 340 and the magnetic return 350 are all divided into two axial segments.

[0092] The first magnet 330 may comprise segments 331 and 332, the second magnet 340 may comprise segments 341 and 342, and the magnetic return 350 may comprisesegments 351 and 352. The segments 331, 341 and 351 may be disposed on the motor side and the segments 332, 342 and 352 may be disposed on the side facing the rotor 370.

[0093] A hollow, cylindrical and / or non-magnetic spacer 430, which may likewise be mounted on the shaft 406, may be disposed between the segments 331 and 332. A further hollow-cylindrical and non-magnetic spacer 430 may be disposed between segments 341 and 351 on the one side and the segments 342 and 352 on the other.

[0094] The segmentation in combination with the offset 450 between the two axial halves may lead to an increase in the magnetic axial force while, at the same time, the transmittable torque decreases. This measure may be taken in the present case because the magnetic axial force is insufficient to reliably compensate the flow force.

[0095] Referring to Figure 12, a cross-sectional view is shown of an embodiment of a rotor bearing system 1 similar to the embodiments shown in Figure 9 and Figure 11 according to some embodiments. The present embodiment differs from the embodiment of Figure 9 in that the second bearing 310 is interchanged with the first bearing 320 and the third bearing 390 and, on the other hand, the axial offset 450 between the first magnet 330 and the second magnet 340 points in the opposite direction as in the embodiment of Figure 9. In embodiments according to Figure 12, the axial offset 450 may be about 1 mm.

[0096] The first magnet 330 and the second magnet 340 may overlap axially at least partially in the axial region identified with the reference sign 460. The first magnet 330 is shown disposed axially offset relative to the second magnet 340. The centers of the first magnet 330 and the second magnet 340 are marked by vertical lines and the axial offset 450 is drawn in between these two vertical lines. In contrast to the embodiment shown in Figure 9, viewed from the housing 380, the first magnet 330 is axially offset relative to the second magnet 340 in the direction of the rotor 370. Between the first magnet 330 and the second magnet 340 in the embodiment shown in Figure 12, there is therefore a defined axial force which acts on the rotor 370 and is directed from the housing 380 toward the rotor 370 along the axis 405; i.e. from right to left in the embodiment shown in Figure 12, which may be distally. A hydraulic force acts on the rotor 370 in the same direction, i.e. likewise from right to left in the embodiment shown in Figure 12. An advantage of this arrangement is that both the magnetic and the hydraulic axial force on the rotor 370 point in the same direction, namelyupstream, as a result of which the rotor 370 is continuously pressed into the combined axial and radial bearing 490.

[0097] The first bearing 320 and the third bearing 390 may likewise form a combined axial and radial bearing 490, which is mounted on the end of the conical part 371 of the rotor 370 facing away from the housing 380. The combined bearing 490 is disposed between the rotor 370 and an insert 210 which is mounted, for example clamped, on a second housing 220 in an annular end, which is in turn mounted on the housing 380. A ball 470, which is disposed on the end of the conical part 371 of the rotor 370 facing away from the housing 380, is hereby pressed in a cone 480 mounted on the insert 210.

[0098] The second bearing 310, which may be configured as a radial, hydrodynamic sliding bearing, may be used to absorb forces and to position the axis of rotation of the second magnet 340, which may be disposed in the rotor 370. The second bearing 310 may be disposed between the housing 380 and the rotor 370. In contrast to the embodiment shown in Figure 9, behind a wall 381 facing toward the rotor 370, the housing 380 of the embodiment shown in Figure 12 comprises a cylindrical journal 382. The journal 382 may be aligned with the shaft. In some embodiments, the journal 382 may effectively continue as an extension of the shaft 406 in the direction of the rotor 370. The journal 382 may be separate from the shaft 406. The journal 382 may be surrounded by a bearing shell 383 of the radial sliding bearing which forms the second bearing 310.

[0099] Referring to Figure 13, a cross-sectional view is shown of a rotor bearing system 1 according to some embodiments. In contrast to embodiments shown in Figures 9-12, the embodiment shown in Figure 13 comprises a magnetic drive in an axially non-overlapping offset configuration rather than an axially overlapping configuration. The two magnets face each other and interact with another in an axial direction and not in a radial direction. As shown in Figure 13 and according to some embodiments, a mechanical circulatory support system may comprise at the proximal end (right side of Figure 13) a housing 380 comprising a shaft 406 (also referred to herein as a drive) with first magnet 330 attached to a rotor-side (distal or left side as shown) of the shaft 406. Adjacent the housing 380 with first magnet 330 on a distal side may be located a rotor end 418 of a rotor 370, the rotor end 418 comprising a hollow cylindrical part 372 where a second magnet 340 may be located.

[0100] Between the rotor end 418 and an end of housing 380 facing the rotor end 418 may be a combined axial and radial bearing 490 comprising a ball 470 and a cone 480. The mechanical circulatory support system may further comprise, at an end of rotor 370 opposite rotor end 418, a second housing 220 that houses rotor tip 420 (left side of Figure 13). As shown in Figure 13 and according to some embodiments, rotor tip 420 may be supported in second housing 220 by a second bearing 310, which may be a radial, hydrodynamic and blood-lubricated sliding bearing. Second housing 220 may serve to both protect the rotor 370 and a patient’s vasculature in which the mechanical circulatory support system is located from damage. Note that as shown and according to some embodiments, rotor 370 may comprise a conical part 371 between rotor end 418 and rotor tip 420. According to some embodiments, a maximum outer diameter of housing 380 and second housing 220 may be less than about 10 mm, and in some embodiments less than about 6 mm.

[0101] As shown in Figure 13 and according to some embodiments, first magnet 330 may interact with second magnet 340, and, via their longitudinal offset, exert a force in the proximal direction that pulls rotor 370 towards housing 380 (labeled Fmag in Figure 13). During operation of the mechanical circulatory support system, shaft 406 may be driven by a motor that rotates shaft 406, and through the magnetic coupling of first magnet 330 on shaft 406 and second magnet 340 at rotor end 418 of rotor 370, as shaft 406 rotates so may rotor 370. This rotation of rotor 370 may allow for the pumping of blood by the mechanical circulatory support system, by which a hydraulic force is imparted in the distal direction on rotor 370 (labeled Fhyd in Figure 13). Fhyd may be related to the rotational speed of rotor 370 and may increase with increasing rotational speed (in addition, the flow of body fluid, i.e. blood, may be increased as well with increasing rotor rotational speed). According to the embodiment shown, Fhyd is opposite to Fmag. With Fmag greater than or equal to Fhyd, ball 470 may be kept in contact with cone 480 of the combined axial and radial bearing 490.

[0102] As shown in Figure 13 and according to some embodiments, ball 470 of the combined axial and radial bearing 490 may be connected to rotor 370 at rotor end 418. Ball 470 may be firmly connected to rotor 370 at rotor end 418 so that when rotor 370 rotates, ball 470 rotates as well. Further, as shown, and according to some embodiments, ball 470 may be connected to rotor 370 through a recess in rotor end 418.

[0103] As shown in Figure 13 and according to some embodiments, cone 480 of the combined axial and radial bearing 490 may be firmly connected to the housing 380 such that any rotation of cone 480 is prevented. Further as shown, and according to some embodiments, cone 480 may be connected to motor housing 380 through a recess in housing 380.

[0104] According to some embodiments, the combined axial and radial bearing 490 comprising of ball 470 and cone 480 may be realized as a pivot bearing and may be designed to compensate axial and radial forces acting on the ball element 470 as uniformly as possible when ball 470 rotates within cone 480. The tribological variables occurring in this geometry, such as friction and wear, may be advantageously minimized, thus increasing efficiency, service life and reliability of the rotor bearing system 1.

[0105] Referring to Figure 14, a cross-sectional view is shown of a rotor bearing system according to some embodiments. As shown and described relative to Figures 9 and I lls, the combined axial and radial bearing 490 may comprise a cone 480 with a base and a cone-like recess 500 and a ball 470 arranged rotatably around a rotation axis and within the cone-like recess 500 of cone 480. The cone-like recess 500 may be adapted to a geometry of the ball 470.

[0106] As shown in Figure 14 and according to some embodiments, a rotor recess 502 of rotor 370 may receive the ball 470. In some embodiments, ball 470 may be firmly connected to rotor 370 via the rotor recess 502. Also shown and according to some embodiments, a housing recess 504 of housing 380 may receive the cone 480. In some embodiments, cone 480 may be firmly connected to housing 380 via the housing recess 504. Cone 480 may comprise an overall cylindrical outer shape, or may comprise a polygonal shape or other shape with or without features that may help secure the cone 480 within housing recess 504 and prevent cone 480 from rotating freely. Ball 470 may comprise an overall spherical outer shape, or may comprise a rod with a half-spherically shaped end, or may comprise other geometry with favorable tribological characteristics on one side (i.e. a side facing the conelike recess 500 of cone 480) and geometry and / or features that may allow for a firm connection with rotor 370 at another side.

[0107] According to some embodiments, ball 470 rotates with rotor 370 via its connection with the rotor 370, and thus may be exhibited to an axial force Faxand radial forceFrad imparted on rotor 370. In some embodiments, the ball 470 may be loaded axially and radially through axial force Faxand radial force Frad, and may impart these forces on cone 480.

[0108] Referring to Figure 15, a cross-sectional view is shown of a rotor bearing system according to Figure 14 and to some embodiments, with the addition of a radius R of ball 470 and an angle a of cone-like recess 500 shown. Additionally, rotational speed co about an axis of rotation, radial force Frad, and axial force Fax are shown. In some embodiments, angle a of cone-like recess 500 and radius R of ball 470 may be optimized for the rotational speed co and forces Frad and Fax. Effects of variations of angle a and radius R are shown later in Figures 16-21 for a ball 470 comprising sapphire and a cone 480 comprising sapphire, a pairing that experimentally proved to be wear-resistant, although the same approach can be taken with other suitable material combinations. The various combinations and resulting performance as shown in Figures 16-21 may be included in or results from the various embodiments described herein, such as the systems of Figures 9-15.

[0109] According to some embodiments, the radius R of ball 470 may be between about 0.2 mm and about 0.7 mm. According to some embodiments wherein ball 470 may not be spherical in shape, the radius R of ball 470 may refer to a half-spherical or semi-spherical side of ball 470 that faces the cone-like recess 500 of cone 480. According to some embodiments, the angle a of cone-like recess 500 may be between about 70 degrees and about 110 degrees. In general, the larger the angle a the less wear may result in the combined axial and radial bearing 490. In some embodiments, the radius R of ball 470 may be about 0.3 mm and the angle a of cone-like recess 500 of cone 480 may be about 100 degrees. According to some embodiments, a geometry optimization suggests the operating parameters of Fax = 2N, Frad = 1.74 N, and co = 35000 rpm.

[0110] Referring to Figure 16, a plot is shown of friction power as a function of angle a of the cone-like recess 500 of cone 480 according to some embodiments, in particular with a ball 470 and cone 480 each comprising sapphire. The friction power is represented by a curve 600, with the x-axis 602 representing angle a of cone-like recess 500 of cone 480 and the y-axis 604 representing friction power P. The friction power represented by curve 600 shown in Figure 16 may occur, for example, in any of the combined axial and radial bearings 490 and / or pivot bearings described herein. As shown, the curve 600 falls, i.e. the frictionpower P decreases, non-linearly with increasing angle a. Conversely, and not shown, the friction power P increases linearly with increasing radius R of ball 470.

[0111] Referring to Figure 17, a plot is shown of wear as a function of time for ball 470 of various radii R according to some embodiments, in particular with a ball 470 and cone 480 each comprising sapphire. The x-axis 702 represents the time h in hours x 104and the y- axis 704 represents wear in pm. Curves 700 shown represent the wear for different radii R of ball 470, which may represent the wear of the combined axial and radial bearing 490 over time for different radii R of ball 470. From top to bottom, the curves 700 represent data for a ball 470 of spherical shape with radii R of 350 pm, 300 pm, and 250 pm.

[0112] Optimizing the radius R of ball 470 may lead to a conflict of objectives, since a larger radius R may result in more friction but less wear. Assuming, for example, that acceptable wear after 10,000 hours would be in the range of about 120 pm, a ball radius of 0.3 mm would be appropriate according to Figure 16 and Figure 17. Contact pressure may then be assessed, and accordingly an optimized contact pressure may comprise an angle a of 100 degrees for the radius R of 0.3 mm.

[0113] Referring to Figure 18, a plot is shown of wear as a function of time for various angles a of the cone-like recess 500 of cone 480 according to some embodiments, in particular with a ball 470 and cone 480 each comprising sapphire. The x-axis 702 represents the time h in hours x 104and the y-axis 704 represents wear in pm. Curves 800 shown represent the wear for different angle a of the cone-like recess 500 of cone 480, which may represent the wear of the combined axial and radial bearing 490 over time for different angle a of the conelike recess 500 of cone 480. From top to bottom, the curves 800 represent data for cone-like recess 500 of cone 480 with angles a of 80 degrees, 90 degrees, and 100 degrees.

[0114] Referring to Figure 19, a plot is shown of stress as a function of radius R of ball 470 according to some embodiments, in particular with a ball 470 and cone 480 each comprising sapphire. This is an example of a Hertzian pressure of contact of the ball 470 with the cone-like recess 500 of cone 480 depending on the radius R of the ball 470. The x-axis 902 represents radius R of ball 470 and the y-axis 904 represents a dependent Hertzian pressure value. Curve 900 as shown falls and begins to flatten as radius R of ball 470 is increased.

[0115] Referring to Figure 20, a plot is shown of stress as a function of angle a of the cone-like recess 500 of cone 480 according to some embodiments, in particular with a ball470 and cone 480 each comprising sapphire. This is an example of a Hertzian pressure of contact of the ball 470 with the cone-like recess 500 of cone 480 depending on the angle a of the cone-like recess 500. The x-axis 1002 represents angle a of the cone-like recess 500 of cone 480 and the y-axis 904 represents a dependent Hertzian pressure value. Curve 1000 as shown falls initially with increasing angle a of the cone-like recess 500 but then increases with continued increasing angle a of the cone-like recess 500.

[0116] Referring to Figure 21, a plot is shown of the ratio of axial stress to radial stress on a combined axial and radial bearing 490 as a function of angle a of the cone-like recess 500 of cone 480 according to some embodiments, in particular with a ball 470 and cone 480 each comprising sapphire. The x-axis 902 represents angle a of the cone-like recess 500 of cone 480 and the y-axis 904 represents the ratio of axial stress (Fax) to radial stress (Frad). The area 1100 above the curve shown represents a range in which the ratio of axial stress to radial stress at corresponding angles a of the cone-like recess 500 are safe for the combined axial and radial bearing 490 and thus for the mechanical circulatory support system.

[0117] Referring to Figure 22, a cross-sectional view of a rotor bearing system is shown according to some embodiments. Similar to embodiments shown in Figures 9-12, the embodiment shown in Figure 22 can have a magnetic drive in an axially overlapping offset configuration. The first magnet and the second magnet may overlap axially at least partially in an axial region, as identified at reference 460 in Figure 9. The first magnet may be disposed axially offset relative to the second magnet and the centers of the first magnet and the second magnet are offset by a set distance.

[0118] As shown in FIG. 22, as a result of the axial offset, the second magnet may experience a force can be directed proximally or toward the right as oriented. In this configuration, an elongated, a bearing component embodied as a cylindrical bearing pin disposed in the rotor is pressed into a recess, such as a jewel bearing mounted in the housing as shown. In another embodiment, the bearing pin is pressed into a cone component mounted in the housing. The pin may be composed of zirconia and the cone component may be sapphire. The pin can have a spherical or hemispherical proximal end that interfaces with the cone, and during proper use, the pin rotates in the cone, similar to the ball in Figure 9. As a result of this configuration, both radial and axial forces can be absorbed. A pin may be used in place of a ball for any of the embodiments herein to create an easier fit into the impeller base when usingadhesive. The elongated shape of a pin may provide more surface area than a ball. Increased surface area can result in a more secure connection to the impeller. Additionally, manufacturing a bore to fit an elongated pin is easier and more secure than a press fit cavity for a ball. The length of the pin in the longitudinal axial direction may be greater than a transverse diameter of the pin. The length of the pin may be more than one and a half, more than two times, more than three times, more than four times, or more, of the diameter of the pin.

[0119] In some embodiments, the pin and / or cone may be formed from various materials such as zirconia, ruby, tungsten, or ceramic. One such embodiment includes the pin comprised of SiC or Si3N4 type ceramics. Due to the geometry of the pin, the material from which the pin is constructed may make the pin more resistant to wear and damage compared to a ball and cone configuration. A stronger pin may be less likely to fracture or fail from repeated use. In certain configurations, the pin may be composed of metal. A metal pin may permit more thermal dissipation due to increased conductivity and contact with the impeller.

[0120] In some embodiments, the hemispherical end of the elongated pin may have a diameter of about 0.5 mm. In some embodiments, the pin end may have a diameter of about 0.6 mm. In some embodiments, the pin end may have a diameter between about 0.4 mm and about 1.4 mm.

[0121] Referring to Figure 23, a cross sectional view through the impeller with a bearing system, magnet coupling, and inlet tube of a microaxial pump is shown. Similar to previous Figures 11 and 12, the impeller 1204 can rotate in housing 1206. Housing 1206 may have pump outlet windows 1209. The impeller 1204 can be supported by a journal bearing 1207 located distally from the impeller 1204. The impeller housing 1206 may extend distally to function as a flexible inlet tube. When the impeller 1204 is driven by magnetic coupling, such as magnets 1202 and 1203, the impeller 1204 cannot be directly mounted to the motor shaft 1201 and therefore requires a separate bearing system to hold components of the system in place. As previously described, different types and shapes of bearings may be used depending on the desired function. For example as shown in Figure 23, the bearing is cylindrically shaped with a central opening 1205. The central opening 1205 can partially receive the ball. The central opening 1205 can be sized just smaller than the ball so that theball is only partially received and can still move as intended against the bearing. This type of bearing with a central opening 1205 may also be used in embodiments with a pin.

[0122] Figure 24 shows an enlarged perspective view of the distal region of the impeller. In some embodiments, this may be the distal end of a portion of the inlet tube. Referring jointly to Figures 23 and 24, a star bearing 1208 may be fixed inside the impeller housing 1206 via a press-fit connection, eliminating the need for additional bearing housing. The illustrated star bearing 1208 can be only one, monolithic component and sits within the impeller housing 1206 holding the journal bearing 1207 in front of the impeller without utilizing extra space, especially in the radial direction, which is valuable for the impeller. The star bearing 1208 may have a central retaining hub that has an opening that receives the distal end of the impeller. The star bearing can have radially extending spokes that extend outwardly from the central retaining hub portion. There may be two spokes, three spokes, four spokes, five spokes, etc. The spokes may be sized and shaped identically to one another around the central hub. The spokes may be spaced equally around the central hub.

[0123] In an embodiment where the star bearing is integrated as a single component, there is no need for multiple bearings in multiple locations as with other flow pump designs. Additionally, the star bearing 1207 does not require connections between the inlet tube and the impeller housing 1206, therefore minimizing radial and axial space for the impeller 1204. Referring to Figure 25, a perspective view of a single-piece impeller cage with integrated star bearing is illustrated in accordance with some embodiments. As an alternative embodiment to Figure 24, the star bearing may be machined into the impeller cage 1301 as a monolithic part as illustrated. The impeller cage may comprise outlet windows 1302 as an alternative to having outlet windows in the impeller housing. Such outlet windows 1302 on the impeller cage 1301 may have rounded or chamfered edges specifically designed to facilitate flow through the pump system. In some embodiments, the impeller cage 1301 in combination with the star bearing is a unibody or machined from a single piece to minimize failure between multiple components.

[0124] Any of the features described herein with respect to FIGS. 1-25 may be used with a variety of different MCS systems and devices, and vice versa. Such different MCS systems and devices include, for example, those as described in U.S. provisional application no. 63 / 116616, filed November 20, 2020 and titled Mechanical Left Ventricular SupportSystem for Cardiogenic Shock, in U.S. provisional application no. 63 / 116686, filed November 20, 2020 and titled Mechanical Circulatory Support System for High Risk Coronary Interventions, in U.S. provisional application no. 63 / 224326, filed July 21, 2021 and titled Guidewire, in international PCT applications no. PCT / EP2019 / 076002 filed September 26, 2019 and titled Sealed Micropump, in PCT / EP2019 / 062731 filed May 16, 2019 and titled Permanent-magnetic radial rotating joint and micropump comprising such a radial rotating joint, in PCT / EP2019 / 062746 filed May 16, 2019 and titled Rotor bearing system, in PCT / EP2019 / 064775 filed June 6, 2019 and titled Line device for a ventricular assist device and method for producing a line device, in PCT / EP2019 / 064780 filed June 6, 2019 and titled Sensor head device for a minimal invasive ventricular assist device and method for producing such a sensor head device, in PCT / EP2019 / 064136 filed May 30, 2019 and titled Line device for conducting a blood flow for a heart support system, and production and assembly method, in PCT / EP2019 / 064807 filed June 6, 2019 and titled Method for determining a flow speed of a fluid flowing through an implanted, vascular assistance system and implantable, vascular assistance system, in PCT / EP2019 / 071245 filed August 7, 2019 and titled Device and method for monitoring the state of health of a patient, in PCT / EP2019 / 071233 filed August 7, 2019 and titled Bearing device for a heart support system, and method for rinsing a space in a bearing device for a heart support system, in PCT / EP2019 / 068434 filed July 9, 2019 and titled Impeller housing for an implantable, vascular support system, in PCT / EP2019 / 069571 filed July 19, 2019 and titled 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 in PCT / EP2019 / 075662 filed September 24, 2019 and titled Method and system for determining a flow speed of a fluid flowing through an implanted, vascular assistance system, the entire disclosure of each of which is incorporated by reference herein for all purposes and forms a part of this specification and description.

[0125] Various modifications to the implementations described in this disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein can be applied to other implementations without departing from the spirit or scope of this disclosure. Thus, the disclosure is not intended to be limited to the implementations shown herein but is to be accorded the widest scope consistent with the claims, the principles and the novel features disclosed herein. The word “example” is used exclusively herein to mean“serving as an example, instance, or illustration.” Any implementation described herein as “example” is not necessarily to be construed as preferred or advantageous over other implementations, unless otherwise stated. The word “about” may refer to values within ±1%, ±2%, ±3%, ±4%, ±5%, ±10%, ±15%, or other ranges depending on context and as may be understood by one of ordinary skill in the art.

[0126] Certain features that are described in this specification in the context of separate implementations also can be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation also can be implemented in multiple implementations separately or in any suitable subcombination. Moreover, although features can be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination can be directed to a sub-combination or variation of a sub-combination.

[0127] Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. Additionally, other implementations are within the scope of the following claims. In some cases, the actions recited in the claims can be performed in a different order and still achieve desirable results.

[0128] It will be understood by those within the art that, in general, terms used herein are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to embodiments containing only one such recitation, even when the same claim includes the introductoryphrases “one or more” or “at least one” and indefinite articles 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 holds true for the use of definite articles used to introduce claim recitations.

[0129] In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, and C” would include but not be limited to systems that have 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.). In those instances where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have 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 within the art that virtually any disjunctive word and / or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities 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.”

[0130] If an exemplary embodiment comprises a “and / or” link between a first feature and a second feature, this is to be read in such a way that the embodiment according to one embodiment has both the first feature and the second feature and according to a further embodiment has either only the first feature or only the second feature.

Claims

WHAT IS CLAIMED IS:

1. A mechanical circulatory support system, comprising: a drive comprising a first magnet; a housing at least partially surrounding the drive; a rotor comprising a blade and a second magnet, wherein the second magnet is magnetically coupled with the first magnet; a cup on the housing, the cup comprising a conical recess; and a ball contacting the rotor and the conical recess of the cup, the ball configured to rotate in the conical recess.

2. The system of claim 1, wherein the ball has a radius of between about 0.2 mm and about 0.7 mm.

3. The system of any one of claims 1 or 2, wherein a profile of the conical recess of the cup has an angle of between about 70 degrees and about 110 degrees.

4. The system of any one of claims 1-3, wherein the cup comprises a cylinder with the conical recess on a circular face of the cylinder.

5. The system of any one of claims 1-4, wherein the ball is positioned on an end of the rotor facing the drive.

6. The system of any one of claims 1-5, further comprising a hydrodynamic radial slide bearing positioned on a distal tip of the rotor facing away from the drive.

7. The system of any one of claims 1-6, wherein the rotor comprises a recess configured to receive the ball.

8. The system of any one of claims 1-7, wherein the housing comprises a recess configured to receive the cup.

9. The system of any one of claims 1-8, wherein at least one of the ball or the cup comprise sapphire.

10. The system of any one of claims 1 -9, wherein the second magnet is configured to cause the rotor to rotate when the first magnet rotates.

11. A mechanical circulatory support system, comprising: a drive comprising: a motor configured to rotate a shaft; anda first magnet configured to be rotated by the shaft, the first magnet at least partially surrounded by a housing; a rotor comprising an impeller and a second magnet, the second magnet at least partially surrounding the housing, the second magnet magnetically coupled with the first magnet such that rotation of the shaft causes the impeller to rotate; and a bearing disposed between a distal face of the housing and a proximal face of the rotor, the bearing configured to allow the rotor to rotate relative to the housing.

12. The system of claim 11, wherein the first magnet and the second magnet are offset along a longitudinal axis and overlapping along a lateral axis.

13. The system of any one of claims 11 or 12, wherein the first magnet and the second magnet are offset along a longitudinal axis and a lateral axis.

14. The system of any one of claims 11-13, the bearing further comprising: a cup comprising a conical recess, the cup being fixed to the housing of the drive; and a ball contacting the rotor and rotatably mounted in the conical recess of the cup.

15. The system of claim 14, wherein the ball has a radius between about 0.2 mm and about 0.7 mm.

16. The system of any one of claims 14 or 15, wherein a profile of the conical recess of the cup has an angle between about 70 degrees and about 110 degrees.

17. The system of any one of claims 14-16, wherein the cup comprises a cylinder with the conical recess on a circular face of the cylinder.

18. The system of any one of claims 11-17, further comprising a hydrodynamic radial slide bearing positioned on an end of the rotor facing away from the drive.

19. The system of any one of claims 14-18, wherein the rotor comprises a recess adapted to receive the ball.

20. The system of any one of claims 14-19, wherein the housing comprises a recess adapted to receive the cup.

21. The system of any one of claims 11-20, wherein the bearing comprises sapphire.

22. The system of any one of claims 11-13, the bearing further comprising: a bearing surface comprising a recess on a distal end of the housing; anda cylindrical bearing pin extending from the impeller, the bearing pin having a proximal end positioned within the recess of the bearing surface.

23. The system of claim 22, wherein the bearing surface comprises a jewel bearing.

24. The system of any one of claims 22 or 23, wherein the recess in the bearing surface is conical.

25. The system of any one of claims 22-24, wherein the proximal end of the bearing pin is round.

26. The system of any one of claims 22-25, further comprising: an inlet tube configured to carry blood therethrough due to rotation of the rotor; and a delivery catheter configured to deliver the rotor to a heart of a patient.

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