Press-fit components, alignment features, bioimpedance measurement elements, and radiopaque markers for a cardiac support system

Abstract

A rotor bearing system for a minimally invasive miniaturized percutaneous mechanical circulatory support system. The rotor bearing system can include a press-fit connection between an inlet tube and an impeller cage. The inlet tube can be made of a flexible material, such as nitinol, such that it can deform around the impeller cage and exert radially inward force to keep the system intact.

Description

KARDN.171W0 PATENTPRESS-FIT COMPONENTS, ALIGNMENT FEATURES, BIOIMPEDANCE MEASUREMENT ELEMENTS, AND RADIOPAQUE MARKERS FOR A CARDIAC SUPPORT SYSTEMINCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

[0001] Any and all applications for which a foreign or domestic priority claim is identified in the Application Data Sheet as filed with the present application are hereby incorporated by reference under 37 CFR 1.57. For example, this application claims priority to U.S. Provisional Application No. 63 / 698,195, titled PRESS-FIT COMPONENTS FOR A CARDIAC SUPPORT SYSTEM and filed September 24, 2024, and U.S. Provisional Application No. 63 / 853,364, titled INTEGRATION OF ALIGNMENT FEATURES, BIOIMPEDANCE MEASUREMENT ELEMENTS, AND RADIOPAQUE MARKERS IN A MECHANICAL CIRCULATORY SUPPORT DEVICE and filed July 29, 2025 the entire contents of each of which is incorporated by reference herein in its entirety for all purposes and forms a part of this specification.BACKGROUNDField

[0002] The technology relates generally to components of a cardiac support system including an inlet tube and an impeller cage.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 can have short lifespansthat provide only temporary mechanical circulatory support. In another example, Cardiogenic shock (CS) is a common cause of mortality, and management remains challenging despite advances in therapeutic options. CS is caused by severe impairment of myocardial performance that results in diminished cardiac output, end-organ hypoperfusion, and hypoxia. Clinically this presents as hypotension refractory to volume resuscitation with features of end-organ hypoperfusion requiring immediate pharmacological or mechanical intervention. Acute myocardial infarction (MI) accounts for over about 80% of patients in CS.

[0004] Conventional systems often include components connected with adhesive. This can cause the systems to fail under a degree of pull force that may be experienced while assisting with pumping blood. There remains a need for a mechanical circulatory support system that can withstand a higher degree of pull force.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, the systems described herein relate to a mechanical circulatory support system, including: an impeller; an impeller cage at least partially surrounding the impeller; and an inlet tube, wherein a proximal end of the inlet tube is radially outward of a distal end of the impeller cage, and wherein the proximal end of the inlet tube continuously applies a radially inward compressive force on the distal end of the impeller cage.

[0007] In some examples, the inlet tube includes a shape memory alloy. In some examples, the inlet tube includes Nitinol. In some examples, the impeller cage includes titanium. In some examples, the impeller cage includes a material that is more rigid than the inlet tube. In some examples, the proximal end of the inlet tube includes a plurality of first alignment features and the distal end of the impeller cage includes a plurality of second alignment features, and wherein the plurality of first alignment features are aligned with theplurality of second alignment features. In some examples, the impeller cage includes a shoulder proximal to the distal end of the impeller cage, the shoulder having a larger diameter than the distal end of the impeller cage, and wherein the proximal end of the inlet tube is radially aligned with the shoulder of the impeller cage. In some examples, the impeller cage includes a bearing configured to retain structure of the impeller cage. In some examples, the bearing continuously applies a radially outward force on the proximal end of the inlet tube. In some examples, the bearing is a star bearing. In some examples, the system can include a motor configured to drive the impeller. In some examples, the impeller is magnetically coupled to the motor. In some examples, the motor is encapsulated such that it is not connected to the impeller by a shaft. In some examples, the impeller is held between bearings. In some examples, the motor is encapsulated in a motor housing. In some examples, the inlet tube comprises a base tube having a flexible section and a coil -reinforced tube disposed over the flexible section of the base tube. In some examples, the coil-reinforced tube comprises a metal coil encapsulated in a polymer. In some examples, the flexible section comprises a helical flexible region between helical windings of a helical mounting surface. In some examples, an electrical conducting element is between an outer surface of the base tube and an inner surface of the coil-reinforced tube.

[0008] In some aspects, the systems described herein relate to a mechanical circulatory support system, including: an impeller; an impeller cage at least partially surrounding the impeller, the impeller cage including a plurality of first alignment features; and an inlet tube including a plurality of second alignment features, wherein a proximal end of the inlet tube is press fit with a distal end of the impeller cage such that the plurality of first alignment features of the impeller cage are aligned with the plurality of second alignment features of the inlet tube.

[0009] In some examples, at least one of the plurality of first alignment features and the plurality of second alignment features are a plurality of holes. In some examples, a diameter of the proximal end of the inlet tube is greater than a diameter of the distal end of the impeller cage. In some examples, the inlet tube includes a shape memory alloy. In some examples, the inlet tube includes Nitinol. In some examples, the impeller cage includes titanium. In some examples, the proximal end of the inlet tube continuously applies a radially inward compressive force on the distal end of the impeller cage. In some examples, the impeller cage includes a shoulder proximal to the distal end of the impeller cage, the shoulder having alarger diameter than the distal end of the impeller cage, and wherein the proximal end of the inlet tube is radially aligned with the shoulder of the impeller cage. In some examples, at least a portion of the inlet tube distal to the impeller cage has an inner diameter smaller than an outer diameter of a mating section of the impeller cage.

[0010] In some aspects, the methods described herein relate to a method for constructing a mechanical circulatory support device, the method including: inserting an inlet tube into an inlet tube holder, the inlet tube including a first plurality of holes and a second plurality of holes, wherein the first plurality of holes are distal to the second plurality of holes; inserting an impeller cage into an impeller cage holder; engaging a plurality of pins of the inlet tube holder in the first plurality of holes of the inlet tube; advancing the inlet tube holder toward the impeller cage holder to advance the inlet tube over the impeller cage, such that a proximal end of the inlet tube and the second plurality of holes are radially outward of a distal end of the impeller cage; retracting the plurality of pins from the first plurality of holes; engaging the plurality of pins in the second plurality of holes; and further advancing the inlet tube holder toward the impeller cage holder to advance the inlet tube over the impeller cage.

[0011] In some examples, the method can include ceasing advancing the inlet tube holder when the second plurality of holes align with a plurality of alignment features of the impeller cage. In some examples, the method can include retracting the plurality of pins from the second plurality of holes. In some examples, the inlet tube is configured to expand as it advances over the impeller cage. In some examples, the inlet tube is configured to expand as it advances over a tapered portion of the impeller cage. In some examples, the method can include removing the inlet tube from the inlet tube holder and removing the impeller cage from the impeller cage holder. In some examples, the method can include cooling the inlet tube before advancing the inlet tube holder toward the impeller cage holder. In some examples, the method can include warming the inlet tube after the inlet tube is advanced over the impeller cage. In some examples, the method can include ceasing advancing the inlet tube holder when the proximal end of the inlet tube abuts a shoulder of the impeller cage, the shoulder having a larger diameter than the distal end of the impeller cage. In some examples, an inner diameter of the inlet tube is smaller than an outer diameter of a mating portion of the impeller cage.

[0012] In some aspects, the methods described herein relate to a method for constructing a mechanical circulatory support device, the method including: inserting an inlettube into an inlet tube holder, the inlet tube including a plurality of holes; inserting an impeller cage into an impeller cage holder; engaging a plurality of pins of the inlet tube holder in the plurality of holes of the inlet tube; and advancing the inlet tube holder toward the impeller cage holder to advance the inlet tube over the impeller cage, such that a proximal end of the inlet tube is radially outward of a distal end of the impeller cage.

[0013] In some examples, the method can include retracting the plurality of pins from the plurality of holes. In some examples, the inlet tube is configured to expand as it advances over the impeller cage. In some examples, the inlet tube is configured to expand as it advances over a tapered portion of the impeller cage. In some examples, the method can include removing the inlet tube from the inlet tube holder and removing the impeller cage from the impeller cage holder. In some examples, the method can include cooling the inlet tube before advancing the inlet tube holder toward the impeller cage holder. In some examples, the method can include warming the inlet tube after the inlet tube is advanced over the impeller cage. In some examples, the method can include ceasing advancing the inlet tube holder when the proximal end of the inlet tube abuts a shoulder of the impeller cage, the shoulder having a larger diameter than the distal end of the impeller cage. In some examples, an inner diameter of the inlet tube is smaller than an outer diameter of a mating portion of the impeller cage.

[0014] In some aspects, the systems described herein relate to a system for constructing a mechanical circulatory support device, including: an inlet tube holder configured to hold an inlet tube, the inlet tube holder including: a plurality of pins, the plurality of pins configured to engage a plurality of holes of the inlet tube; and a pin actuator configured to transition the plurality of pins between an engaging position and a retracted position; and an impeller cage holder configured to hold an impeller cage.

[0015] In some examples, the inlet tube holder is restricted to translational movement toward and away from the impeller cage holder. In some examples, the impeller cage holder is restricted to translational movement toward and away from the inlet tube holder. In some examples, the inlet tube holder includes a rotational orientation locking component configured to prevent the inlet tube from rotating about a central axis. In some examples, the impeller cage holder includes a rotational orientation locking component configured to prevent the impeller cage from rotating about a central axis.

[0016] In some aspects, the techniques described herein relate to a cardiac assist system including a guide cannula including an inlet tube having one or more helical slots and an inlet opening for receiving blood, the guide cannula arranged between a sensor head unit and an end unit including a proximal sensor and a motor, an outlet opening for discharging the blood, and an electrical conducting element coupled to the inlet tube of the guide cannula proximate the one or more helical slots, the electrical conducting element including a plurality of layers and a sensor contact region configured to contact at least one sensor, where the electrical conducting element contacts the proximal sensor.

[0017] In some aspects, the techniques described herein relate to a system wherein the one or more helical slots include a plurality of helical slots and wherein at least a portion of the electrical conducting element is disposed between two adjacent helical slots.

[0018] In some aspects, the techniques described herein relate to a system wherein the electrical conducting element passes around the motor.

[0019] In some aspects, the techniques described herein relate to a system wherein the end unit further includes a void proximal from the motor.

[0020] In some aspects, the techniques described herein relate to a system wherein the electrical conducting element includes a flexible printed circuit board.

[0021] In some aspects, the techniques described herein relate to a system one or more sensors in electrical contact with the electrical conducting element.

[0022] In some aspects, the techniques described herein relate to a system wherein the electrical conducting element is connected to one or more distal sensors disposed in a distal tip of the guide cannula.

[0023] In some aspects, the techniques described herein relate to a system wherein the electrical conducting element is connected to one or more proximal sensors disposed in a proximal cap of the guide cannula.

[0024] In some aspects, the techniques described herein relate to a conduit for a cardiac assist system, the conduit including a guide cannula comprising a sheath, and an electrical conducting element helically wound around the sheath of the guide cannula, where the electrical conducting element includes a plurality of alignment indicators.

[0025] In some aspects, the techniques described herein relate to a conduit wherein the plurality of alignment indicators are configured to align circumferentially with one another.

[0026] In some aspects, the techniques described herein relate to a conduit wherein the plurality of alignment indicators comprise tabs or notches.

[0027] In some aspects, the techniques described herein relate to a conduit wherein the electrical conducting element further includes bend portions configured to adjust an alignment of the electrical conducting element.

[0028] In some aspects, the techniques described herein relate to a conduit wherein the sheath further includes one or more helical slots.

[0029] In some aspects, the techniques described herein relate to a conduit wherein the sheath further includes one or more guide indicators.

[0030] In some aspects, the techniques described herein relate to a conduit wherein the one or more guide indicators include spaces between the helical slots.

[0031] In some aspects, the techniques described herein relate to a conduit wherein the one or more guide indicators include laser etchings on the sheath.

[0032] In some aspects, the techniques described herein relate to a conduit for a cardiac assist system, the conduit including a guide cannula including an inlet tube, and one or more radiopaque markers disposed on the inlet tube, wherein the one or more radiopaque markers include a first radiopaque marker disposed at a distal end of a landing zone, and a second radiopaque marker disposed at a proximal end of the landing zone.

[0033] In some aspects, the techniques described herein relate to a conduit wherein the landing zone is a region along a length of the guide cannula configured to align with an aortic valve of a patient during operation of the cardiac assist system.

[0034] In some aspects, the techniques described herein relate to a conduit wherein the one or more radiopaque markers are integral to an electrical conducting element.

[0035] In some aspects, the techniques described herein relate to a conduit including one or more helical slots disposed on the inlet tube and an inlet opening for receiving blood.

[0036] In some aspects, the techniques described herein relate to a conduit wherein the electrical conducting element includes a flexible printed circuit board, the electrical conducting element configured to electrically connect components along a length of the inlet tube.

[0037] In some aspects, the techniques described herein relate to a conduit wherein the one or more radiopaque markers wrap around a circumference of the inlet tube.

[0038] In some aspects, the techniques described herein relate to a conduit wherein the one or more radiopaque markers wrap around at least a half of a circumference of the inlet tube.

[0039] In some aspects, the techniques described herein relate to a conduit for a cardiac assist system, the conduit including a guide cannula including an inlet tube, an electrical conducting element helically wound around the inlet tube of the guide cannula, the electrical conducting element including one or more electrode pads, and one or more electrodes arranged on the one or more electrode pads.

[0040] In some aspects, the techniques described herein relate to a conduit wherein the electrical conducting element includes a four-wire micro ribbon cable.

[0041] In some aspects, the techniques described herein relate to a conduit wherein the one or more electrodes are soldered to the electrical conducting element.

[0042] In some aspects, the techniques described herein relate to a conduit wherein the one or more electrodes includes conductive portions of the guide cannula, wherein the conductive portions are separated by one or more insulative regions.

[0043] In some aspects, the techniques described herein relate to a conduit wherein the one or more electrodes are clamped to the electrical conducting element, and wherein the one or more electrodes are configured to communicate signals to a controller configured to measure bioimpedance.

[0044] In some aspects, the techniques described herein relate to a conduit wherein the one or more electrodes includes a first pair of electrodes positioned in a distal region of the electrical conducting element.

[0045] In some aspects, the techniques described herein relate to a conduit wherein the one or more electrodes includes a first pair of electrodes positioned in a proximal region of the electrical conducting element.

[0046] In some aspects, the techniques described herein relate to a conduit wherein the one or more electrodes further includes a second pair of electrodes positioned in a distal region of the electrical conducting element.BRIEF DESCRIPTION OF THE DRAWINGS

[0047] 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.

[0048] Figure 1 is a cross-sectional rendering of a mechanical circulatory support (MCS) device mounted on a catheter and positioned across an aortic valve via a femoral artery access according to some embodiments.

[0049] Figure 2 schematically illustrates the access pathway from the femoral artery to the left ventricle.

[0050] Figure 3 is a side elevational view of a mechanical circulatory support system according to some embodiments.

[0051] Figure 4 shows the system of Figure 3, with the introducer sheath removed and including an insertion tool and a guidewire back loading aid according to some embodiments.

[0052] Figure 5 shows an introducer kit having a sheath and dilator according to some embodiments.

[0053] Figure 6 shows a placement guidewire according to some embodiments.

[0054] Figure 7 shows an example of an MCS system with a press-fit inlet tube and impeller cage according to some embodiments.

[0055] Figure 8 shows a perspective view of the inlet tube of Figure 7.

[0056] Figure 9 shows a side view of the inlet tube of Figure 7.

[0057] Figure 10 shows a cross-sectional view of the connection section of the inlet tube of Figure 7.

[0058] Figure 11 shows a perspective view of the impeller cage of Figure 7.

[0059] Figure 12 shows a side view of the impeller cage of Figure 7.

[0060] Figure 13 shows a cross-sectional side view of the impeller cage of Figure7.

[0061] Figure 14A shows a side view of the tapered portion of the impeller cage of Figure 7.

[0062] Figure 14B shows a side view of a landing zone of an impeller cage.

[0063] Figure 15 shows a cross-sectional end view of the connection section of the impeller cage of Figure 7.

[0064] Figures 16A-16E show an example of an inlet tube in an inlet tube holder and an impeller cage in an impeller cage holder illustrating a press-fit connection process.

[0065] Figure 17 shows an example of a method for assembling an inlet tube and an impeller cage.

[0066] Figure 18 illustrates an exploded front view of an MCS system with a press- fit inlet tube and impeller cage according to some embodiments.

[0067] Figures 19A and 19B illustrate detailed views of a portion of an MCS system with a press-fit inlet.

[0068] Figure 20 shows an example a base tube according to some embodiments.

[0069] Figure 21 is a perspective view of a mechanical circulatory support device including a guide cannula, inlet and outlet openings, and a motor housing.

[0070] Figure 22A is a perspective view of a guide cannula including a guidewire port region and a tolerance section in the electrical conducting element.

[0071] Figure 22B-22F are perspective detailed views of portions of a guide cannula illustrating the configuration of electrical conducting elements thereon.

[0072] Figure 23 is a front view of an electrical conducting element, including detailed views of the connection portions of the electrical conducting element.

[0073] Figure 24 is a cross-sectional view of the proximal end of a motor housing, illustrating the arrangement of an electrical conducting element around an electronics module within a proximal cap.

[0074] Figure 25 is a perspective view of the proximal end of a motor housing with the proximal cap removed.

[0075] Figure 26 is a front view of an arrangement of electrodes on an electrical conducting element for a cardiac assist system.

[0076] Figure 27 a perspective view of an arrangement of electrode pads on a four- wire micro ribbon cable for bioimpedance measurement.

[0077] Figure 28 is a front view of an arrangement of electrodes on an electrical conducting element for a cardiac assist system.

[0078] Figure 29 shows a perspective view of a guide cannula having segmented, integrated electrodes.

[0079] Figure 30 is an illustration of a cardiac assist system positioned within a patient's heart, illustrating the alignment of the guide cannula with the aortic valve.

[0080] Figure 31 is a radiographic image illustrating the functionality of radiopaque markers in a cardiac assist system.

[0081] Figure 32 is a perspective view of a guide cannula with radiopaque markers.

[0082] Figure 33 is a front view of an electrical conducting element including radiopaque markers.

[0083] 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

[0084] 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 someembodiments” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. 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 present disclosure, 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.Cardiac Assist System Overview

[0085] Aspects of the present disclosure will be described with reference to a Mechanical Circulatory Support (MCS) system (e.g., cardiac assist system) including a ventricular support device. However, it will be understood that the present disclosure is not limited to implementation in ventricular support devices and / or MCS systems, and the various innovative aspects described herein may equally be implemented in other devices without departing from the scope of this disclosure. The cardiac assist system may include an inlet tube portion that extends across the aortic valve of a heart. An impeller of the cardiac assist system may be located at least partially at the outflow section (in the ascending aorta) of the inlet tube drawing blood from the left ventricle of the heart and may eject the blood into the ascending aorta. The cardiac assist system can include a motor, which can be mounted directly proximal to the impeller in an encapsulated housing eliminating the need to purge the motor prior to or during use. The cardiac assist system can actively unload blood from the left ventricle by pumping blood from the ventricle and ejecting the pumped blood into the ascending aorta and systemic circulation.

[0086] In general, the overall cardiac assist system can include a series of related subsystems and accessories, including one or more of the following. The cardiac assist system may include an elongate flexible catheter shaft with an inlet tube, an impeller, a motor, and sensors and associated housings, and a proximal hub, an insertion tool, a proximal cable, aninfection shield, a guidewire guide tube, and / or a guidewire aid. The cardiac assist system may be provided sterile. The cardiac assist system may contain the electrical cables and a guidewire lumen for over-the-wire insertion. The proximal hub may contain a guidewire port (e.g., a guidewire outlet) with a valve to maintain hemostasis and connect the ventricular support shaft to the proximal cable, where the proximal cable connects the cardiac assist system to a controller. A cardiac assist system insertion tool can be a part of the cardiac assist system to facilitate the insertion of a pump of the cardiac assist system into an introducer sheath and to protect an inlet tube and hemostasis valves from potential damage or interference when passing through the introducer sheath. A peel-away guidewire aid may be pre-mounted on the cardiac assist system to facilitate the insertion of a guidewire. A guidewire having a soft, coiled, preshaped tip for atraumatic wire placement into the left ventricle. The guidewire may be provided sterile. An introducer sheath that is expandable in diameter may be used. The introducer sheath may maintain access into the femoral artery and provide hemostasis for the guidewire, the diagnostic catheters, the placement guidewire, and the insertion tool. The housing of the introducer sheath may accommodate the cardiac assist system insertion tool. The introducer sheath may be provided sterile. An introducer dilator compatible with the introducer sheath may be used to facilitate atraumatic insertion of the introducer sheath into the femoral artery. The introducer dilator may be provided sterile. A cardiac assist system controller may be used, which drives and operates the cardiac assist system, observes its performance and condition as well as providing error and status information. The powered controller may be designed to support at least about 12 hours of continuous operation and contains a basic interface to indicate and adjust the level of support provided to the patient. Moreover, the cardiac assist system controller may provide an optical and / or audible alarm notification in case the cardiac assist system detects an error during operation. The cardiac assist system controller may be provided non-sterile and 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 removably plugged. Any of the above features may be included in the embodiments shown in the figures.

[0087] The MCS system as described herein may include a temporary (generally no more than about 6 hours) left ventricular support device for use during high-risk percutaneous coronary intervention (PCI) performed in elective or urgent, hemodynamicallystable patients 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 system 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 stable patients 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 system as described herein may include a long-term 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 via a single femoral arterial access.

[0088] As described with respect to FIGS. 7-17, the MCS system can include a press-fit inlet tube and an impeller cage. Advantageously, this can allow the MCS system to withstand a higher degree of pull force. The press-fit connection between the inlet tube and impeller cage can improve the strength of the MCS system. The press-fit connection between the inlet tube and impeller cage can offer an advantage over alternative manufacturing methods due to its inherent mechanical integrity. By precisely machining the mating surfaces of the components to tight tolerance, the parts can be forcibly joined together to create an interference fit. This can result in a high-strength bond, distributing the load evenly across the interface, enhancing structural integrity, and minimizing stress concentrations. In current devices in the field, welding can introduce heat-affected zones and potential metallurgical alterations, leading to weakened material properties and susceptibility to corrosion. Adhesives, while providing flexibility in design, can cause a lack of shear strength and durability. Devices joined using adhesives can be compromised by environmental factors such as temperature fluctuations and forces in the bloodstream.

[0089] The inlet tube and impeller cage can include features that make it easier to form a press-fit connection. For example, the inlet tube can be made of a shape memory alloy, for example Nitinol. The inlet tube can be stretched over the impeller cage. The inlet tube can provide a compressive force around the impeller cage as it is biased to return to its original shape. The inlet tube can include holes that allow it to be manipulated using pins for ease of forming a press-fit connection. The inlet tube and impeller cage can exhibit design featuresconducive to a seamless press-fit connection, facilitating an easier assembly process. The geometries of the inlet tube and impeller cage can ensure compatibility and alignment during mating. The surfaces of the inlet tube and impeller cage can be engineered to optimize contact and friction, enhancing the stability of the press-fit connection. The MCS device can lack mating grooves, threads, and bumps, as they are not required for the press-fit connection. A press-fit connection can be inspected by measuring the mating components and ensuring alignment is correct. This can obviate the need for inspection of an adhesive joint.

[0090] The system may include a low-profile axial rotary blood pump mounted on a catheter such as an 8 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 partial left ventricular support (for example, in some cases an MCS pump may provide up to about 4.0 liters / minute, 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.

[0091] 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.

[0092] Certain embodiments of the inlet tube described herein advantageously allow the inlet tube to resist radial deformation when under pressure, while allowing longitudinal flexibility needed for delivery of the blood pump through tortuous vessels. Further, the inlet tubes can support an electrical conducting element such that the electrical conducting element is not damaged during longitudinal flexion. Advantageously, the inlet tubes described herein may include variable flexibility along the length of the inlet tube, a guidewire port (e.g., a guidewire outlet), inlet openings, outlet openings, and / or radiopaque markers.

[0093] Advantageously, certain embodiments of assist devices described herein can eliminate tight bends and / or eliminate tight tolerance requirements in an electricalconducting element of the assist device. Additionally, the electrical conducting elements described can advantageously be accurately assembled on the assist device due to alignment features on the electrical conducting element and / or laser-cut slots on an inlet tube of the assist device. Additionally, the assist devices described herein can integrate radiopaque markers into the electrically conducting element to improve visualization of the device during insertion under medical imaging, aiding in the precise positioning of the assist device across the aortic valve. Furthermore, the assist devices described can incorporate bioimpedance measurement capabilities by utilizing the electrically conductive element to connect electrodes for impedance measurement. These advancements both individually and collectively contribute to a more reliable, efficient, and multifunctional cardiac assist system.

[0094] In this description, reference is made to the accompanying drawings. In the drawings, similar symbols typically identify similar components, unless context dictates otherwise. Thus, in some embodiments, part numbers may be used for similar components in multiple figures, or part numbers may vary from figure to figure. The illustrative embodiments described herein 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. It will be readily understood that the aspects of the present disclosure and illustrated in the figures can be arranged, substituted, combined, and designed in a wide variety of different configurations by a person of ordinary skill in the art, all of which are made part of this disclosure.

[0095] Reference in the 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 disclosure. Moreover, the appearance of these or similar phrases throughout the specification does not necessarily mean that these phrases all refer to the same embodiment, nor are separate or alternative embodiments necessarily mutually exclusive. Various features are described herein 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.

[0096] Reference in the specification to directional terms may be used for purposes of describing the orientation and positioning of components described herein. Accordingly, thefollowing definitions will be used: “proximal” means towards or near a particular reference point, including but not limited to toward or closer to a vasculature access point along a path of a transcatheter assist system; and “distal” means away or far from a particular reference point, including but not limited to away from or farther from a vasculature access point along a path of a transcatheter assist system.

[0097] Figure 1 shows a rendering of an example embodiment of a MCS device mounted on the tip of a catheter such as an 8 Fr catheter. An inlet tube portion of the device extends across the aortic valve. The impeller is located at the outflow section of the inlet tube drawing blood from the left ventricle and ejecting it into the ascending aorta. 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).

[0098] The device can actively unload 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, for example, between 0.4 1 / min up to 4.0 1 / min of partial left ventricular support.

[0099] In some examples, the device can be a minimally invasive miniaturized percutaneous mechanical left ventricular support system, optimized for treatment of patients experiencing cardiogenic shock. The system can include a low profile (e.g., 18 Fr to 19 Fr) MCS device which can include an axial rotary blood pump and an elongate inlet tube, carried by the distal end of a nine French catheter. The system can be positioned to span the MCS device across the aortic valve into the left ventricle, where it actively unloads the left ventricle by pumping blood from the left ventricle into the ascending aorta and systemic circulation, and may provide flow rates of up to about 6 L per minute at 60 mmHg. In some embodiments, flow rates between 0.6 L per minute and 6 L per minute may be provided.

[0100] In some examples, the device can include a motor that is completely sealed by encapsulation within a motor housing, having a magnetic coupling to allow the motor to drive the impeller without the need for a shaft to leave the housing. The magnetic coupling can include a cylindrical driving magnet array positioned within the motor housing, concentrically positioned within a cylindrical driven magnet array located outside of the motor housing andmechanically coupled to the impeller. The impeller can rotate with respect to the motor housing about a pivot jewel bearing. The magnetic coupling can be flushed by a constant blood flow through flushing holes on proximal and distal ends of the magnetic coupling. The sealed motor can enable elimination of a purging process necessary for certain competitive devices. In some examples, the inlet tube can be directly connected to the motor housing using the systems and methods described herein.

[0101] In general, the overall MCS system may include a series of related subsystems and accessories. The MCS Device may include 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. In some embodiments, 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. In some embodiments, the proximal hub may contain a guidewire port (e.g., 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. In some embodiments, the proximal cable is 3.5 m (approx. 177 inch) in length and extends from the sterile field to the non-sterile field where the MCS Controller is located. In some embodiments, the MCS device includes an MCS insertion tool as part of the MCS Device to facilitate the insertion of the pump into the Introducer Sheath and to protect the inlet tube and the valves from potential damage or interference when passing through the Introducer Sheath. In some embodiments, the MCS device includes a peel-away guidewire aid premounted on the MCS Device to facilitate the insertion of the 0.018” placement guidewire into the pump and into the MCS shaft. In some embodiments, the MCS device includes a 3 m 0.018” placement guidewire, having a soft coiled pre-shaped tip for atraumatic wire placement into the left ventricle. The guidewire is provided sterile. In some embodiments, the MCS device includes a 14 Fr Introducer Sheath with a usable length of 275 mm 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. In some embodiments, the housing of the Introducer Sheath is designed to accommodate the MCS Insertion Tool. The Introducer Sheath is provided sterile. In some embodiments, the MCS device includes an introducer dilator compatible with the Introducer Sheath to facilitate atraumatic insertion of the IntroducerSheath into the femoral artery. The introducer dilator is provided sterile. In some embodiments, the MCS device includes an MCS Controller which drives and operates the MCS Device and observes its performance and condition as well as providing 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 can be contained in an enclosure designed for cleaning and re-use outside of the sterile field. The controller enclosure contains a socket into which the extension cable is plugged.

[0102] Referring to Figure 3, there is illustrated 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. They could 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 / explantation to be visible under fluoroscopy.

[0103] 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.

[0104] 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 hub34. 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 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.

[0105] 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 one commercial presentation of the system, the MCS device as 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.

[0106] Referring to Figures 5 and 6, an introducer kit 610 may include a guidewire 600, an introducer sheath 612, a dilator 614, and a guidewire aid 38, discussed above. The guidewire 600 may comprise an elongate flexible body 601 extending between a proximal end 602 and a distal end 604. A distal zone of the body 601 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 606 may be configured to facilitate threading through the MCS device, and can extend between the proximal end 602 and a transition 608. The proximal zone 606 may have an axial length within the range of from about 100 mm to about 500 mm (e.g., about 300 mm).

[0107] The introducer kit 610 may comprise a sheath 612 and a dilator 614. The sheath 612 may comprise an elongate tubular body 616, extending between a proximal end 618 and a distal end 620. The tubular body 616 may terminate proximally in a proximal hub 622. The tubular body 616 may be expandable or may be configured to be peeled apart. The proximal hub 622 may include a proximal end port 624 in communication with a central lumenextending throughout the length of the tubular body 616 and out through a distal opening, configured for axially removably receiving the elongate dilator 614. Proximal hub 622 may additionally be provided with a side port 626, at least one and optionally two or more attachment features such as an eye 628 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 600, and the insertion tool 32.Example MCS Devices Including Press-fit Inlet Tube Embodiments

[0108] FIG. 7 shows an example of an MCS device 700 with a press-fit inlet tube 702 and impeller cage 704. The MCS device 700 is a non-limiting example implementation of the device illustrated in FIGS. 1-6. The MCS device 700 can be used in conjunction with the other components in FIGS. 1-6, or can be used with other components in a different setting. The MCS device 700 can be inserted into a vessel of a patient to increase blood flow. The inlet tube 702 can allow blood to enter the MCS device 700 while in the bloodstream. The inlet tube 702 can include guidewire port (e.g., a guidewire outlet) 714 for allowing a guidewire to pass through the inlet tube 702. The impeller cage 704 can contain an impeller 705, which can rotate to increase blood flow. The inlet tube 702 can have a distal tip 706, or cap, for leading the MCS device 700 as it is guided through the bloodstream. The motor 716 can drive the impeller 705. The bend relief 718 can provide flexibility to the proximal end of the impeller cage 704 for maneuvering through vessels.

[0109] The inlet tube 702 can be a made of Nitinol, for example laser-cut Nitinol. The inlet tube 702 can be made of a flexible material such that it can deform around the impeller cage 704 and exert radially inward force to keep the system intact. The inlet tube 702 can be flexible such that it can bend while in the vasculature. For example, the laser-cut Nitinol tube may have slots arranged on the tube to impart a desired flexibility. In some embodiments, the inlet tube 702 can include coating, for example polyurethane or silicone coating. The coating may occlude the laser-cut slots to contain blood flow within the inlet tube and may protect surrounding tissue that may come into contact with the MCS device 700. In some embodiments, the inlet tube 702 can be made of a polymeric material, a shape-memory alloy, a wire-enforced polymer, or superelastic nitinol with an austenite transformation finish (Af)temperature below body temperature (e g. below room temperature). The inlet tube 702 can be elastically deformed, for example stretched, and can apply a strong elastic force to return toward its unconstrained configuration.

[0110] A pump inlet may be in fluid communication with a pump outlet by way of a flow path extending axially through an inlet tube 702. The pump inlet may be positioned at or about the transition between the inlet tube 702 and the proximal end of distal tip 706. The distal tip 706 can be an atraumatic distal tip, for example with a central guidewire opening 707. The distal tip 706 can be a nose piece. The distal tip 706 can include sensors, for example a pressure sensor, a temperature sensor, or any other suitable sensor.[OlH] The inlet tube 702 can include a guidewire port 714. The guidewire port 714 can allow a guidewire to stay clear of the impeller 705. A guidewire can pass through the central guidewire opening 707 at the distal end of the distal tip 706 and through the inlet tube 702. The guidewire can pass through the guidewire port 714 and extend proximally outside the MCS device 700. Advantageously, the impeller 705 can be located within the body of the MCS device 700 without risk of the guidewire contacting the impeller 705 because of the guidewire port 714.

[0112] The proximal end of the inlet tube 702 can be a connection section 712. The connection section 712 can include a set of distal holes 708 and a set of proximal holes 710. The connection section 712 of the inlet tube 702 can include four distal holes 708. In some embodiments, the connection section 712 of the inlet tube 702 can include 1-10 or more distal holes 708. The connection section 712 of the inlet tube 702 can include four proximal holes 710. In some embodiments, the connection section 712 of the inlet tube 702 can include 1-10 or more proximal holes 710. Each distal hole 708 can be aligned with a corresponding proximal hole 710.

[0113] The distal holes 708 and the proximal holes 710 can be evenly distributed about the circumference of the inlet tube 702. Alternatively, in some embodiments the distal holes 708 and the proximal holes 710 can be unevenly distributed about the circumference of the inlet tube 702, such as in groups of 2, 3, or more. In one particular non-limiting example, the distal holes 708 can be 2.4 mm from the proximal end of the inlet tube 702. In some embodiments, the distal holes 708 can be 2-3.5 mm from a proximal end of the inlet tube 702. In some embodiments, the distal holes 708 can be 1-5 mm from the proximal end of the inlettube 702. Tn some embodiments, the distal holes 708 can be 0.5-6 mm from the proximal end of the inlet tube 702. The proximal holes 710 can be 1.7 mm from the proximal end of the inlet tube 702. In some embodiments, the proximal holes 710 can be 1-2.5 mm from the proximal end of the inlet tube 702. In some embodiments, the proximal holes 710 can be 0.5-3.5 mm from the proximal end of the inlet tube 702. In some embodiments, the proximal holes 710 can be 0.2-5 mm from the proximal end of the inlet tube 702. Other spacings may also be implemented.

[0114] The distal holes 708 may be in a row that is further from the proximal end of the inlet tube 702 than the proximal set of holes 710 is, such as by a distance in a range of 1.5 to 2.5 mm. In some embodiments, the distal set of holes 708 may be in a row that is further from the proximal end of the inlet tube 702 than the proximal set of holes 710 is, by a distance in a range of 0.5 to 3.5 mm. In some embodiments, the distal set of holes 708 may be in a row that is further from the proximal end of the inlet tube 702 than the proximal set of holes 710 is, by a distance in a range of 0.2 to 5 mm. Other spacings may also be implemented.

[0115] Each hole 708, 710 may be a cylindrical bore through the wall of the inlet tube, having a diameter of about 0.9 mm. The holes may be through holes extending through the full thickness of the wall of the inlet tube, or may be blind holes that do not extend through the full thickness of the wall of the inlet tube. In some embodiments, each hole can have a diameter in the range of 0.5 to 1.5 mm. In some embodiments, each hole can have a diameter in the range of 0.1 to 2.5 mm. In some embodiments, the proximal set of holes 710 or distal set of holes 708 may be staggered.

[0116] The impeller cage 704 can be made of metal, for example titanium. The impeller cage 704 can be rigid. For example, the impeller cage 704 can be made of a material that is more rigid than the inlet tube 702. The impeller cage 704 can house or carry at least a portion of a rotor or impeller 705 therein. The rotor or impeller can convert mechanical power into hydraulic power for supporting a blood flow against a blood pressure. The impeller cage 704 may serve to protect both the rotor or impeller 705 and a patient’s vasculature in which the mechanical circulatory support system is located from damage. The rotor or impeller 705 can be a magnetically coupled impeller 705 (e.g., coupled to the motor 716 by a magnetic coupling) in some embodiments. In other implementations, the rotor or impeller 705 can be mechanically coupled to the motor 716 such as by a drive shaft.

[0117] Forming a connection between the inlet tube 702 and impeller cage 704 such as by welding can be difficult due to differences in material properties. Using adhesive to connect the inlet tube 702 and impeller cage 704 can be unreliable and reduce the ability of the device 700 to withstand pull force. As an advantageous alternative to welding or adhesives, the inlet tube 702 and impeller cage 704 can be connected using a press-fit in accordance with the present disclosure. Non-limiting examples of methods for manufacturing the MCS device 700 with a press-fit are described with respect to FIGS. 16A-E and 17.

[0118] A proximal end or connection section 712 of the inlet tube 702 can be disposed radially outward of a distal end of the impeller cage 704. As the inlet tube 702 can be press-fit with the impeller cage 704, the proximal end or connection section 712 of the inlet tube 702 can apply a radially inward compressive force on the distal end of the impeller cage 704. In some embodiments, the proximal end of the inlet tube 702 can continuously apply the radially inward compressive force on the distal end of the impeller cage 704. The inward pressure applied from the inlet tube 702 to the impeller cage 704 can maintain the connection between the inlet tube 702 and the impeller cage 704.

[0119] The MCS device 700 can include a motor 716 configured to drive the rotor or impeller 705, such as by a magnetic or mechanical coupling. In some embodiments, the motor 716 can be a customize 4-pole BLDC motor or any other suitable motor. The proximal end of the motor 716 can include an integrated proximal pT MEMS sensor.

[0120] The MCS device 700 can include abend relief 718. The bend relief 718 may provide flexibility proximal to the impeller cage 704. The bend relief 718 can improve the maneuverability of the MCS device 700.

[0121] FIGS. 8-10 depict the inlet tube 702 of FIG. 7. FIG. 8 shows a perspective view of the inlet tube 702 of FIG. 7. FIG. 9 shows a side view of the inlet tube 702 of FIG. 7. FIG. 10 shows an end view of the connection section 712 of the inlet tube 702 of FIG. 7.

[0122] The inlet tube 702 can have an open proximal end and / or an open distal end. The inlet tube 702 can include a guidewire port 714 (e.g., an opening) for allowing the guidewire to avoid contact with the impeller. The inlet tube 702 can include a connection section 712 with holes 708, 710 for manipulating the connection section 712 during formation of the press-fit connection. The proximal holes 710 can be aligned with the distal holes 708.

[0123] As shown in FIG. 10, the connection section 712 can be defined by an outer diameter 730 and an inner diameter 732 defining a wall thickness between them. The inner diameter of the connection section 712 of the inlet tube 702 can be sized to fit around an impeller cage without compromising the structural integrity of the MCS device. The wall thickness can ensure adequate strength and rigidity to withstand the pressures of assembly and use. The wall thickness can be sized to allow the connection section 712 of the inlet tube 702 to sufficiently stretch over the impeller cage without compromising the structure of the inlet tube 702. The inlet tube 702 can be cylindrical. The inlet tube 702 can have a circular or ovular profile on both ends.

[0124] In a non-limiting example, the connection section 712 of the inlet tube 702 can have an outer diameter 730 of 5.98 mm. In some embodiments, the connection section 712 of the inlet tube 702 can have an outer diameter 730 of 4-7 mm. In some embodiments, the connection section 712 of the inlet tube 702 can have an outer diameter 730 of 2-10 mm. The connection section 712 of the inlet tube 702 can have another outer diameter 730. In some implementations, the outer diameter 730 of the inlet tube 702 can be consistent along the length of the inlet tube 702.

[0125] In a non-limiting example, the connection section 712 of the inlet tube 702 can have an inner diameter 732 of 5.71 mm. In some embodiments, the connection section 712 of the inlet tube 702 can have an inner diameter 732 of 4-7 mm. In some embodiments, the connection section 712 of the inlet tube 702 can have an inner diameter 732 of 2-10 mm. The connection section 712 of the inlet tube 702 can have another inner diameter 732. In some implementations, the inner diameter 732 of the inlet tube 702 can be consistent along the length of the inlet tube 702.

[0126] In a non-limiting example, the connection section 712 of the inlet tube 702 can have a wall thickness of 0.27 mm. In some embodiments, the connection section 712 of the inlet tube 702 can have wall thickness of 0.1-0.4 mm. In some embodiments, the connection section 712 of the inlet tube 702 can have a wall thickness of 0.05-0.7 mm. The connection section 712 of the inlet tube 702 can have another wall thickness. In some implementations, the wall thickness of the inlet tube 702 can be consistent along the length of the inlet tube 702.

[0127] FIGS. 11-13 depict the impeller cage 704 of FIG. 7. FIG. 11 shows a perspective view of the impeller cage 704 of FIG. 7. FIG. 12 shows a side view of the impellercage 704 of FIG. 7. FIG. 13 shows a side view of the impeller cage 704 of FIG. 7. In some embodiments, the impeller cage 704 can be a mating component. The impeller cage 704 can have a radial support component 780, which can provide greater mechanical stability for the press-fit connection. The radial support component 780 can include spokes 784 that can distribute inward forces applied by the inlet tube. The spokes 784 can extend from a central hub 782. The impeller cage 704 can include a connection section 766 for forming a press-fit connection with the inlet tube. For example, the connection section of the inlet tube can be fit around the exterior of the connection section 766 of the impeller cage 704. The impeller cage 704 can include outlet windows 786 for allowing blood to enter the MCS device and contact the impeller.

[0128] A radial support component 780, or bearing, may be integrally formed with the impeller cage 704, or impeller housing. The radial support component 780 can include spokes 784 and the hub 782. The radial support component 780 may provide radial support to the connection section 766 of the impeller cage 704. The radial support component 780 can also hold the distal impeller bearing. The radial support component 780 may be a star bearing. The radial support component 780 can be only one, monolithic component and sits within the impeller cage 704. The radial support component 780 can be positioned in front of the impeller such that the impeller is unimpeded from rotation. The radial support component 780 may have a central retaining hub 782. The hub 782 can have an opening that receives the distal end of the impeller 705. The radial support component 780 can have radially extending spokes 784 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.

[0129] The radial support component 780 may be machined into the impeller cage 704 as a monolithic part. Such outlet windows 786 on the impeller cage 704 may have rounded or chamfered edges specifically designed to facilitate flow through the pump system. The outlet windows 786 on the impeller cage 704 may be curved to allow enhanced radially outward flow from the impeller. In some embodiments, the impeller cage 704 in combination with the radial support component 780 can be a unibody or machined from a single piece to minimize failure between multiple components.

[0130] FIG. 14A shows a cross-sectional view of the tapered portion 768 of the impeller cage 704 of FIG. 7. FIG. 14B shows an enlarged cross-sectional view of the tapered portion 768 including a landing zone 1470 of an impeller cage.

[0131] As shown in FIG. 14A, the impeller cage 704 can have a tapered portion 768 on the exterior side of the distal end of the connection section 766. The connection section 766 of the impeller cage 704 may have a tapered or chamfered distal outer edge. The tapered portion 768 may facilitate the step of engaging and advancing the inlet tube over the connection section 766. For example, the inner circumference of the inlet tube may slide along the slope of the tapered portion 768 to expand the inlet tube and engage the press-fit connection.

[0132] In a non-limiting example, the tapered portion 768 can have a 15 degree chamfer. In some embodiments, the tapered portion 768 can have a 5-30 degree chamfer. In some embodiments, the tapered portion 768 can have a 1-50 degree chamfer. In various nonlimiting example embodiments, the tapered portion 768 can have a 15 degree chamfer, a chamfer between 5 and 30 degrees, a chamfer between 1 and 50 degrees, or any other suitable chamfer angle.

[0133] As shown in FIG. 14B, the interior side of the connection section 1466 of the impeller cage may have a landing zone 1470 and a tapered portion 1468. The impeller cage can be the impeller cage described with respect to other Figures herein. The landing zone 1470 can be a portion at the end of the connection section 1466 with a shallow slope. The inlet tube can easily engage with the landing zone 1470. The inner diameter of the inlet tube can advance over the landing zone 1470 before further advancing over the tapered portion 1468. The tapered portion 1468 can be a portion proximal to the landing zone along the connection section with a steeper slope. The tapered portion 1468 can force the inlet tube to expand to engage in the press-fit connection.

[0134] In a non-limiting example, the landing zone 1470 may have a taper with an angle of 8 degrees. In some embodiments, the landing zone 1470 may have a taper with an angle of 0-15 degrees. In some embodiments, the landing zone 1470 may have a taper with an angle of 0-30 degrees. The landing zone 1470 may have a radiused edge. The landing zone 1470 may further facilitate engagement with the inlet tube in a manufacturing process. Optionally, the landing zone 1470 and / or the tapered portion 1468 may be a curved surface. In some embodiments, the landing zone 1470 may meet the slope to the tapered portion 1468 ata point. In some embodiments, the slope may gradually change from the landing zone 1470 to the tapered portion 1468 with a curve.

[0135] FIG. 15 shows an end view of the connection section 766 of the impeller cage 704 of FIG. 7. In some embodiments, the impeller cage 704, or mating component, can be a cylinder. In some embodiments, the impeller cage 704 can include three spokes 784 connected to a central hub 782 inside the cylinder.

[0136] The connection section 766 of the impeller cage 704 can have an outer diameter of 5.9 mm. In some embodiments, the connection section 766 of the impeller cage 704 can have an outer diameter of 4-7 mm. In some embodiments, the connection section 766 of the impeller cage 704 can have an outer diameter of 2-10 mm.

[0137] The connection section 766 of the impeller cage 704 can have an outer diameter 734 greater than the inner diameter 732 of the inlet tube 702. This can cause the inlet tube 702 to expand over the impeller cage 704, for example by forcing the inlet tube 702 over the impeller cage 704. The connection section 766 of the impeller cage 704 can have an outer diameter 734 smaller than the inner diameter 732 of the inlet tube 702. This way, the tapered portion 768 of the connection section 766 of the impeller cage 704 can enter the inlet tube 702. The inlet tube 702 can then be forced to expand as it is forced along the slope of the tapered portion 768.

[0138] In some embodiments, the connection section 766 of the impeller cage 704 proximal to the tapered portion 768 can have an outer diameter 734 greater than or equal to the inner diameter 732 of the inlet tube 702. This can allow the proximal end of the inlet tube 702 connection section 712, in particular the inner proximal edge on the inner diameter, to engage with the tapered portion 768 or landing zone of the impeller cage 704. For example, the proximal end of the inlet tube 702 connection section 712 can engage with the tapered portion 768 or landing zone of the impeller cage 704 when the proximal end of the inlet tube 702 connection section 712 is coaxially aligned with the distal end of the connection section 766 of the impeller cage 704 and moved along the central axis until they connect. The inner diameter 736 of the impeller cage 704 can be sized based on the outer diameter 734 of the impeller cage 704.

[0139] The inner diameter 732 of the inlet tube 702 can be 0.019 mm smaller than the outer diameter 734 of the impeller cage 704. In some embodiments, the inner diameter 732of the inlet tube 702 can be 0.01-0.03 mm smaller than the outer diameter 734 of the impeller cage 704. In some embodiments, the inner diameter 732 of the inlet tube 702 can be 0.005- 0.05 mm smaller than the outer diameter 734 of the impeller cage 704. In some embodiments, the inner diameter 732 of the inlet tube 702 can be 0.001-0.1 mm smaller than the outer diameter 734 of the impeller cage 704, or any other suitable amount smaller. The inner diameter 732 of the inlet tube 702 can be 2%-4% smaller than the outer diameter 734 of the impeller cage 704. In some embodiments, the inner diameter 732 of the inlet tube 702 can be 1 %-l 0% smaller than the outer diameter 734 of the impeller cage 704. In some embodiments, the inner diameter 732 of the inlet tube 702 can be 0.1%-20% smaller than the outer diameter 734 of the impeller cage 704, or any other suitable factor smaller.

[0140] The impeller cage 704 may include a radial support component 780, or radial support structure. The radial support component 780 may provide structural support to the connection section 766. Advantageously, the radial support component 780 may help to resist deformation under the compression applied by the inlet tube 702 connection section 712. The radial support component 780 may have 3 spokes 784 that connect a central hub with the inner surface of the connection section 766. In some embodiments, the radial support component 780 may have 2-5 spokes that connect a central hub with the inner surface of the connection section 766. In some embodiments, the radial support component 780 may have 1- 8 spokes that connect a central hub with the inner surface of the connection section 766. The spokes 784 of the radial support component 780 can evenly spaced, for example to distribute force evenly around the circumference of the impeller cage 704.

[0141] The radial support component 780 may be at or near the distal end of the connection section 712. The central hub may have a radial support component 780 for engaging with an impeller. The radial support component 780 may be coaxial with the impeller housing and inlet tube when assembled. The radial support component 780 may be a star bearing.

[0142] The radial support component 780 may exert radially outward force on the inlet tube 702. In some implementations, the radial support component 780 can be a reinforcement component, a coil, a braided mesh, a reinforcing rib or ring, or a polymeric component. The radial support component 780 can maintain the structure of the impeller cage 704 or mating component when the inlet tube 702 provides force on the impeller cage 704.Example Process for Inlet Tube-Impeller Cage Press-Fit Connection

[0143] FIGS. 16A-16E show an example of a process for press-fit connection between an inlet tube 1602 and an impeller cage 1604. The inlet tube holder 1652 can pull the inlet tube 1602 over the impeller cage 1604, which is held by the impeller cage holder 1654. The inlet tube 1602 can have an inner diameter 1632 greater than the smallest diameter of the tapered portion 1668 of the impeller cage 1604. Therefore, the inlet tube 1602 can be advanced over the impeller cage 1604. The inlet tube 1602 can have an inner diameter 1632 smaller than the greatest diameter of the tapered portion 1668 of the impeller cage 1604. Therefore, as the inlet tube 1602 is advanced over the impeller cage 1604, the inlet tube 1602 can be forced to expand and form a press-fit connection. The inlet tube holder 1652 can use pins 1656 that are inserted into holes 1608, 1610 of the inlet tube 1602 to force the inlet tube over the impeller cage 1604. FIG. 16A shows an example of an inlet tube 1602 and an impeller cage 1604 before press-fit connection. FIG. 16B shows an example of the inlet tube 1602 and the impeller cage 1604 of FIG. 16A before press-fit connection. FIG. 16C shows an example of the inlet tube 1602 in and the impeller cage 1604 of FIG. 16A during press-fit connection. FIG. 16D shows an example of the inlet tube 1602 and the impeller cage 1604 of FIG. 16A during press-fit connection. FIG. 16E shows an example of the inlet tube 1602 and the impeller cage 1604 of FIG. 16A during press-fit connection.

[0144] The inlet tube 1602 and impeller cage 1604 can be the inlet tube 702 and the impeller cage 704 of the MCS system as described with respect to FIGS. 7-15, or either or both of the inlet tube 1602 and impeller cage 1604 may be alternative components configured for press-fit connection.

[0145] The inlet tube holder 1652 can include pins 1656 configured to be seat within corresponding apertures of the inlet tube 1602. The pins 1656 can be retractable. The inlet tube holder 1652 can include four pins 1656. In some embodiments, the inlet tube holder 1652 can include 1-10 or more pins 1656. The pins 1656 may be movable between an aperture engaging position 1658 and a retracted position 1660. In the aperture engaging position 1658, the pins protrude into the apertures at least partially or completely through apertures 1610 of the inlet tube 1602, or even beyond the inner side wall of the inlet tube 1602. In the retracted position 1660, the pins are not in the apertures. In retracted position 1660, the pins 1656 can be removed from the exterior side of the wall of the inlet tube 1602. The inlet tube holder 1652can have a tubular cavity 1690 that is sized and shaped to contain the inlet tube 1602. The inlet tube holder 1652 may be longitudinally split into two halves that can be opened to provide easy access to the cavity. In some embodiments, the inlet tube holder 1652 may be opened and closed using a hinge or a sliding component.

[0146] The pins 1656 may be transitioned between the aperture engaging position 1658 and the retracted position 1660 using a pin actuator 1662. The pin actuator 1662 can be manually or automatically actuated. The inlet tube holder 1652 may have a rotational orientation locking component that holds the inlet tube 1602, preventing it from rotating about its central axis with respect to the inlet tube holder 1652. The inlet tube holder 1652 can restrict the inlet tube 1602 to translational movement toward and away from the impeller cage holder 1654. The locking component may be actuated by a locking actuator 1664. The pin actuator 1662 and lock actuator 1664 can be buttons or switches. The pin actuator 1662 and lock actuator 1664 can be positioned on top of the inlet tube holder 1652.

[0147] The impeller cage holder 1654 may have a cavity sized and shaped to accommodate at least a portion of the impeller cage 1604 while exposing the distal end of the impeller cage 1604. The impeller cage holder 1654 may have a rotational orientation locking component that holds the impeller cage 1604, preventing it from rotating about its central axis with respect to the impeller cage holder 1654. The impeller cage holder 1654 can restrict the impeller cage 1604 to translational movement toward and away from the inlet tube holder 1652.

[0148] The distal end of the impeller cage 1604 can include a narrow portion, or connection section 1666, with a smaller diameter than the rest of the impeller cage 1604. The distalmost end of the narrow connection section 1666 of the impeller cage 1604 can include a tapered portion 1668 in which the diameter tapers from the diameter of the narrow connection section 1666 to the smaller diameter of the inner cavity 1676 of the impeller cage 1604. The cavity of the impeller cage holder 1654 may be accessible by opening two halves of the impeller cage holder 1654. Both the impeller cage 1604 and the impeller cage holder 1654 may have a rotationally engaging feature that aligns the impeller cage 1604 rotationally and prevents it from rotating with respect to the impeller cage holder 1654. The impeller cage holder 1654 may have a locking actuator 1670 that holds the impeller cage 1604 firmly in the impeller cage holder 1654. In some embodiments, the impeller cage holder 1654 and the inlettube holder 1652 may be connected to one another, for example, via a base that restricts movement of both holders and allows only translational movement along the horizontal axis 1692. The translational movement may be manually actuated, for example with a lever, or may be automated.

[0149] In some examples, the method described herein can be carried out with alternative mating components in the place of the inlet tube 1602 and / or impeller cage 1604. The method described herein can be carried out to press-fit a flexible tube with a rigid device.

[0150] As shown in FIG. 16A, the inlet tube 1602 can be inserted into the inlet tube holder 1652. The connection section 1612 of the inlet tube 1602 can be aligned with the inlet tube holder 1652 such that pins 1656 align with the distal holes 1608 of the inlet tube 1602. The pins 1656 can enter the distal holes 1608 of the inlet tube 1602 while in the engaging position 1658. The pins 1656 can hold the inlet tube 1602 in place. The impeller cage 1604 can be held by the impeller cage holder 1654 such that the impeller cage 1604 is aligned with the inlet tube 1602 about the horizontal axis.

[0151] As shown in FIG. 16B, the inlet tube holder 1652 can be advanced with the inlet tube 1602 toward the impeller cage 1604 with a translational movement along the horizontal axis. The pins 1656 engaged in the distal holes 1608 can transfer force from the inlet tube holder 1652 to the inlet tube 1602. Accordingly, the inlet tube 1602 can be advanced onto the tapered portion of the impeller cage 1604 by advancing the inlet tube holder 1652 along the axis 1692.

[0152] As shown in FIG. 16C, when the proximal end of the inlet tube 1602 abuts against the tapered portion 1668 the force between the pins and the impeller cage 1604 can compress the connection section 1612. With continued advancement along the axis 1692 (FIG. 16B), this can cause the connection section 1612 of the inlet tube 1602 to stretch and expand radially as it slides along the slope of the tapered portion 1668. The translational movement may continue until at least the position shown in FIG. 16C, in which the proximal holes 1610 are disposed beyond the tapered portion 1668 and onto the narrow connection section 1666 of the impeller cage 1604. The distal holes 1608 can remain distal to the narrow connection section 1666 of the impeller cage 1604. The pins 1656 may be engaged fully through the distal holes 1610 and protruding into the inner lumen in the inlet tube 1602. Advantageously, using pins to advance the inlet tube 1602 over the impeller cage 1604 may be a secure engagementoption, for example with a reduced risk of human error compared to manually forcing the inlet tube 1602 over the impeller cage 1604.

[0153] In some examples, such as where the inlet tube 1602 comprises a shape memory alloy, the inlet tube 1602 may be cooled below a transformation temperature during the process of advancing the inlet tube 1602 over the impeller cage 1604. For example, a Nitinol inlet tube 1602 may be cooled below the Nitinol's Af temperature. This can transition the shape memory alloy (e.g., can transition Nitinol to a martensite phase), allowing it to be more easily deformed and therefore be more easily advanced and stretched over the connection section 1666 of the impeller cage 1604. When the Nitinol warms to above the Af temperature, for example when at room temperature or body temperature, the Nitinol transitions from martensite to austenite phase and recovers the pseudoplastic deformation, thus remembering its previously defined shape and compressing around the connection section of the impeller cage.

[0154] As shown in FIG. 16D, the pins 1656 can be retracted from the distal holes 1608. The pins 1656, which may be the same pins or different pins, can be engaged into the proximal holes 1610. The pins 1656 may be spring loaded such that when they are moved into the engaging position 1658 they will advance radially inward until physically blocked or until a limit is achieved. For example, when the spring-loaded pins 1656 are moved into the engaging position 1658 through apertures and there is no object on the inner side of the aperture to block the pins, they may advance further up to a limit. When the pins are moved through apertures and there is an object such as the outer surface of the narrow connection section 1666 of the impeller cage 1604 blocking the inner opening of the aperture, the pins may stop when contacting the narrow connection section 1666.

[0155] As shown in FIG. 16E, the inlet tube holder 1652 can be further advanced along with the inlet tube 1602 further toward the impeller cage 1604 with the pins 1656 engaged in the proximal holes 1610. The translational movement along the horizontal axis of the inlet tube holder 1652 with respect to the impeller cage 1604 can continue to apply force from the pins 1656 to the proximal set of holes 1610, which can pull the connection section 1612 of the inlet tube 1602 over the narrow connection section 1666 of the impeller cage 1604 until the proximal end of the inlet tube 1602 abuts against a shoulder 1674 of the impeller cage 1604. The shoulder 1674 may have a thickness substantially equal to the wall thickness of theinlet tube 1602 so the outer surface of the MCS system has a smooth transition from the shoulder 1674 to the outer surface of the inlet tube 1602 at the press fit connection.

[0156] In some embodiments, such as where the inlet tube 1602 comprises a shape memory alloy the inlet tube 1602 may be warmed to above a transformation temperature (e.g., above the Af temperature for a Nitinol inlet tube) once the inlet tube 1602 is fully advanced so it can apply a strong compressive and frictional force. The warming may be done before or after removing the assembly from the holders.

[0157] The assembled inlet tube 1602 and impeller cage 1604 can be removed from the inlet tube holder 1652 and the impeller cage holder 1654, respectively. The pins 1656 may first be retracted from the apertures and the lock actuators 1664, 1670 if used may be released. In some embodiments, the method described herein can be partially or entirely automated by an algorithm executed by a processor based on computer-executable instructions stored in a non-transitory computer-readable medium.

[0158] In some examples, only one set of holes may be present on the inlet tube 1602 and the pins may apply force to the one set of holes for the assembly process. For example, the pins 1656 may be spring loaded and have a sloped tip. When the sloped tip of the pin 1656 engages with the sloped surface of the tapered portion 1668 of the impeller cage 1604, the sloped tip may slide along the tapered portion 1668, causing the pin 1656 to retract, allowing forward motion to continue. In some embodiments, the pins 1656 can extend only into the apertures and not into the lumen of the inlet tube 1602, such that they are pushed radially outward when the connection section 1612 of the inlet tube 1602 expands.

[0159] In some examples, the inlet tube 1602 may have outlet openings cut into it. In some examples, the inlet tube may be press fit onto a motor housing. An assembly tool may engage pins into the outlet openings to advance the inlet tube over a connection section of the motor housing.

[0160] The impeller cage 1604 may have alignment features that can line up with the proximal set of holes 1610. In some embodiments, the impeller cage 1604 may have alignment features that can line up with the distal set of holes 1608. The alignment features can be a set of holes on the impeller cage 1604. The pins 1656 can engage holes of the impeller cage 1604 when a set of holes 1608, 1610 of the inlet tube 1602 aligns with the holes of the impeller cage 1604. The alignment features can be one or more protrusions, ridges, serrations,or knurls. A user can cease advancing the inlet tube holder when a plurality of holes 1608, 1610 align with a plurality of alignment features of the impeller cage 1604.

[0161] In some embodiments, the press fit assembly may resist a pull force of up to 80 to 100 N. In some embodiments, the press fit assembly may resist a pull force of up to 50 to 150 N. In some embodiments, the press fit assembly may resist a pull force of up to 20 to 200 N, or any other suitable pull force. The achievable pull force may be based on inlet tube wall thickness, inlet tube inner diameter, inlet tube outer diameter, impeller cage connection section outer diameter, impeller cage connection section length, and / or Nitinol properties such as composition of nickel and titanium or Af temperature.Example Method of Inlet Tube - Impeller Cage Assembly

[0162] FIG. 17 shows an example of a method 1700 for assembling an inlet tube and an impeller cage. The method 1700 can be implemented in conjunction with any of the components, devices, and systems described here, and may include the configurations shown in FIGS. 16A-16E. Although the method 1700 will be described with reference to the components of FIGS. 16A-16E, it may equally be implemented in conjunction with any other suitable system.

[0163] At block 1788, a user can insert the inlet tube 1602 into an inlet tube holder 1652. The inlet tube holder 1652 may have a tubular cavity 1690 that is sized and shaped to contain the inlet tube, and retractable pins arranged to align with and protrude into one of the proximal and distal set of apertures. The pins 1656 may be movable between an aperture engaging position wherein the pins 1656 protrude into the apertures at least partially, preferably completely, or even through the inner side, and a retracted position, wherein the pins 1656 are not in the apertures 1608, 1610 (e.g., removed from the exterior side of the inlet tube wall). The inlet tube holder 1652 may be longitudinally split into two halves that can be opened (e.g., about a hinge) to provide easy access to the cavity 1690. The cavity 1690 may have an inner diameter in the area of the connection section that accommodates the outer diameter of the connection section of the inlet tube 1602 when it is stretched over the connection section of the mating component. The pins 1656 may be transitioned from the engaging position to the retracted position with a pin actuator that may be manually or automatically actuated. The inlet tube holder 1652 may have a rotational orientation lockingmechanism that holds the inlet tube 1602 preventing it from rotating about its central axis with respect to the inlet tube holder 1652. The locking mechanism may be actuated by a lock actuator 1664.

[0164] At block 1790, a user can insert the mating component into a mating component holder 1654. The mating component can be an impeller cage 1604. The mating component holder 1654 may have a cavity sized and shaped to accommodate at least a portion of the mating component while exposing the connection section 1666. The cavity may be accessible by opening two halves of the holder. Both the mating component and its holder 1654 may have a rotationally engaging feature that can align the mating component rotationally and prevents it from rotating with respect to the holder 1654. The holder 1654 may have a locking actuator 1670 that can hold the mating component firmly in the holder. The mating component holder 1654 and the inlet tube holder 1652 may be connected to one another for example via a base that restricts movement of both holders and allows only translational movement along the central axis. The translational movement may be manually actuated (e.g., with a lever) or be automated.

[0165] At block 1792, a user can engage the pins 1656 in the distal set of apertures and advance the inlet tube holder 1652 along with the inlet tube toward the mating component. The pins 1656 engaged in the distal set of apertures can transfer force from the inlet tube holder 1652 to the inlet tube 1602. When the proximal end of the inlet tube 1602 abuts against the mating component (e g., the sloped surface or tapered portion 1668) the force between the pins 1656 and the mating component, or impeller cage 1604, can compress the connection section causing it to stretch and expand radially as it slides along the slope. The translational movement may continue until the proximal set of apertures 1610 is advanced over the connection section of the mating component and the distal set of apertures 1608 is not, particularly in an example wherein the pins are fully through the apertures and protruding into the inner lumen in the inlet tube 1602.

[0166] At block 1794, a user can retract the pins 1656 from the distal set of apertures 1608 and engage the pins into the proximal set of apertures 1610. The pins 1656 may be spring loaded such that when they are moved into the engaged position they will advance radially inward until physically blocked or until a limit is achieved. For example, when the spring-loaded pins 1656 are moved into the engaged position through apertures 1608, 1610and there is no object on the inner side of the aperture to block the pins, they may advance further up to a limit. When the pins are moved through apertures 1608, 1610 and there is an object such as the outer surface of the mating component's connection section 1666 blocking the inner opening of the aperture, the spring-loaded pins 1656 may stop when contacting the surface.

[0167] At block 1796, a user can advance the inlet tube holder 1652 along with the inlet tube 1602 further toward the mating component, or impeller cage 1604, with the pins 1656 engaged in the proximal set of apertures 1610. The translational movement along the central axis of the inlet tube holder 1652 with respect to the mating component holder can continue to apply force from the pins to the proximal set of apertures 1610, which can pull the connection section 1612 of the inlet tube over the connection section 1666 of the mating component, or impeller cage 1604, until the proximal end of the inlet tube 1602 abuts against a shoulder 1674 of the mating component. The shoulder 1674 may have a thickness substantially equal to the wall thickness of the inlet tube 1602 so the outer surface of the mating component has a smooth transition to the outer surface of the inlet tube 1602 at the press fit connection. The mechanical circulatory device can have a consistent outer diameter at the point of press-fit connection. In some embodiments, the user can retract the pins 1656 from the proximal set of apertures 1610 and engage the pins in the distal set of apertures 1608 to further advance the inlet tube 1602. The steps described with respect to blocks 1792, 1794, and / or 1796 can be repeated.

[0168] At block 1798, a user can remove the assembled inlet tube 1602 and mating component, or impeller cage 1604, from the holders. The pins 1656 may be retracted from the apertures 1608, 1610 and the locking mechanisms, if used may be released.

[0169] In some examples, such as where the inlet tube 1602 comprises a shape memory alloy, the inlet tube 1602 may be cooled below a transformation temperature during the process of advancing the inlet tube 1602 over the impeller cage 1604. For example, a Nitinol inlet tube 1602 may be cooled below the Nitinol's Af temperature. This can transition the shape memory alloy (e.g., can transition Nitinol to a martensite phase), allowing it to be more easily deformed and therefore be more easily advanced. Optionally, the manufacturing process or part of it may be automated by an algorithm stored on a processor.Example Hybrid Inlet Tube Embodiments

[0170] FIG. 18 depicts an example inlet tube 1800 in both an exploded state and an assembled state. FIGS. 19A and 19B depict a detailed view of a proximal end of the inlet tube 1800. FIG. 20 depicts a base tube 1804 of the inlet tube 1800. The inlet tube 1800 can include a coil-reinforced tube 1802, a base tube 1804, and an electrical conducting element 1806. The inlet tube 1800 can attach to an impeller cage 704 or other proximal component at a proximal end and can attach to a sensor head 1840, a cap, or other distal component at a distal end. The sensor head 1840 can house one or more sensors (e.g., pressure sensors, ultrasound sensors, temperature sensors, impedance sensors, optical sensors, acoustic sensors, or other sensors). The electrical conducting element 1806 can connect to the sensor in the sensor head 1840 and can connect to any other sensor or other electrically connectable component positioned along the proximal region of the inlet tube 1800 and / or on a proximal component such as the impeller cage 704. The electrical conducting element 1806 can include, for example, any of the features described with regard to the electrical conducting elements 180, 280, 380, 480, described with reference to FIGS. 21-29.

[0171] FIGS. 19A and 19B depict a detailed view of the inlet tube 1800 including the coil-reinforced tube 1802. The coil-reinforced tube 1802 can be formed from a polymer. The coil-reinforced tube 1802 may include a coil 1808 (e.g. helix) embedded in polymer 1809. This coil-reinforced tube 1802 may be positioned on the exterior surface of the electrical conducting element 1806 with the base tube 1804 positioned on the interior surface of the electrical conducting element 1806, where the electrical conducting element 1806 is sandwiched between the base tube 1804 and the coil-reinforced tube 1802, as shown in FIGS 19A and 19B. A benefit of this orientation is that the coil -reinforced tube 1802 can function to hold the electrical conducting element 1806 in place. Alternatively, the coil-reinforced tube 1802 may be positioned on the interior surface of the base tube 1804 and the electrical conducting element 1806 may be positioned on the exterior surface of the base tube 1804. Advantageously, this arrangement of the coil-reinforced tube 1802, the base tube 1804, and the electrical conducting element 1806 may facilitate the coil-reinforced tube 1802 providing a smooth interior surface in the inlet tube 1800 which benefits the flow profile of blood through the inlet tube 1800. Additionally, the electrical conducting element 1806 may be more easilyaccessible from the exterior surface for connecting sensors along the length of the inlet tube 1800 in some embodiments.

[0172] The coil 1808 may be cylindrical, and / or a helix. The coil 1808 may be made from a metal such as stainless steel, a shape memory alloy such as Nitinol, or other suitable metal. The coil 1808 may include one or more strands, wires, and / or ribbons. The coil1808 may have a thickness in a range of between 0.076 mm - 0.12 mm, or any value therebetween. In some embodiments, the coil 1808 may have a helical pitch in a range of between 0.35 mm - 0.95 mm, or any value therebetween. In some embodiments, the coil 1808 can have a strand or ribbon with a width 1811 in a range of 0.2 mm - 0.6 mm, or any value therebetween. In some embodiments, a pitch of the coil 1808 can vary along the longitudinal length of the inlet tube 1800. In some embodiments, the pitch of the coil 1808 can be tighter at a proximal region of the inlet tube 1800 than a distal region. In some embodiments, a strand or ribbon width 1811 of the coil 1808 can vary along the longitudinal length of the inlet tube 1800. In some embodiments, the pitch of the coil 1808 can be wider at a proximal region of the inlet tube 1800 than at the distal region. In some embodiments, the coil 1808 can have a constant outer diameter 1812. In some embodiments, the outer diameter of the coil 1808 is in a range of 6.0 mm - 6.25 mm, or any value therebetween. In some embodiments, the constant outer diameter 1812 is in a range of 6.0 mm - 6.25 mm, or any value therebetween.

[0173] The coil 1808 can be embedded in a polymer 1809. The polymer 1809 may be a biocompatible flexible polymer, for example, PEBAX. In some embodiments, the polymer1809 may encapsulate the coil 1808 on one or both of the inner and outer surfaces of the coil 1808. In some embodiments, the polymer 1809 can have a wall thickness 1813 in a range of 0.23 mm - 0.40 mm, or any value therebetween.

[0174] In some embodiments, the coil-reinforced tube 1802 may include one or more electrical conducting elements arranged in the helical pattern and embedded in the surface of the coil-reinforced tube 1802. The embedded electrical conducting elements may be in addition to or as a replacement for one or more strands (e.g., wires or ribbons) of the 1808 coil. The one or more electrical conducting elements may extend from the distal and / or proximal ends of the coil-reinforced tube 1802 to connect to a sensor or electronics module.

[0175] FIG. 20 illustrates a front view of a base tube 1804. The base tube 1804 can be a laser cut tube. The base tube 1804 can be a sheet welded into a tube shape. The base tube1804 can be formed from a shape memory material (e.g., Nitinol). The base tube 1804 may have one or more of the properties of the inlet tubes described herein, for example, the inlet tubes 120, 702, and / or 1602.

[0176] The base tube 1804 may include a tube section 1820, a proximal connection section 1821 extending proximally from the tube section 1820, and a distal connection section 1822 extending distally from the tube section 1820. The wall thickness of the base tube 1804 may be constant across each of its sections. In some embodiments, the wall thickness of the base tube 1804 can be in a range of 0.05mm - 0.15 mm, or values therebetween. The tube section 1820 may have a length substantially equal to the length of the coil-reinforced tube 1802. The coil-reinforced tube 1802 may be disposed over the tube section 1820.

[0177] The tube section 1820 may be connected to the inner or the outer surface of the coil-reinforced tube 1802. The tube section 1820 and coil-reinforced tube 1802 may be connected with adhesive or by a friction fit. In some embodiments, the tube section 1820 may be covered with another polymer layer (e.g. dip coating, over molding) to sandwich the base tube 1804 between the coil-reinforced tube 1802 and the another polymer layer.

[0178] The tube section 1820 may include laser cuts forming a helical mounting surface 1823 to which the electrical conducting element 1806 may be mounted. The tube section 1820 may include a helical flexible region 1824 between helical windings of the helical mounting surface 1823, as shown in FIG. 20. In some embodiments, the laser cuts may include a helical flexible region 1824 including a plurality of slots with an uncut helical mounting surface 1823 therebetween. The plurality of slots may define bands 1830 of the base tube 1804 having a width 1829 that is thinner than the mounting surface width 1826. In some embodiment, the bands 1830 may be varied in width or distance along the length of the inlet tube 1800 to vary the flexibility of the inlet tube 1800. In some embodiments, the width of the bands 1830 may be greater toward the proximal end and gradually decrease in the distal direction of the inlet tube 1800. Advantageously, the bands 1830 decreasing in width from the proximal end towards the distal end can facilitate an inlet tube 1800 that is more flexible toward the distal end, which may benefit with improved handling while delivering the heart pump to a patient’s heart. The width 1829 may be in a range of 1 / 10 to 1 / 4 the mounting surface width 1826. The plurality of slots may be oriented transverse to the longitudinal axis or helically. The plurality of helically oriented slots may be at the same helical pitch as the helical mountingsurface. The plurality of helically oriented slots may be at a different pitch than the helical mounting surface 1823 such as a smaller or larger pitch. The helical path may have the same helical handedness or opposite that of the helical mounting surface 1823 and / or the coil 1808. In some embodiments, the laser cuts may be in the form of a continuous helical gap 1825, as shown in FIG. 18. The helical mounting surface 1823 may have a width 1826 sufficient to mount the electrical conducting element 1806, and a pitch that may be the same pitch as the pitch as the coil 1808.

[0179] The proximal connection section 1821 may extend proximally from the tube section 1820 and from the coil-reinforced tube 1802. The proximal connection section 1821 may include the press-fit connection features described herein, for example in FIGS. 7-15. In some embodiments, the proximal connection section 1821 can include proximal and distal holes 708, 710 on the proximal connection section 712 (FIG. 9) as well as dimension and material allowing it to be press-fit over an impeller cage 704 or motor housing. The proximal connection section 1821 may have the same inner diameter, outer diameter and wall thickness as the tube section 1820. In some embodiments where the inlet tube 1800 is connected directly to a motor housing, the proximal connection section 1821 may include outlet windows.

[0180] The distal connection section 1822 may extend distally from the tube section 1820 and from the coil-reinforced polymer tube 1802 and may include connection features described herein, for example in FIGS. 7-15. In some embodiments, the distal connection section 1822 can include a press-fit connection and / or a surface for adhesion for connecting to a distal sensor head 1840. The distal connection section 1822 may have the same inner diameter, outer diameter, and / or wall thickness as the tube section 1820.

[0181] Although not shown in FIG. 20, the base tube 1804 may include a guidewire port, such as guidewire port 714, 134 described elsewhere herein. The guidewire port may be an oblong hole in the side of the base tube 1804 surrounded by an uncut region of the base tube 1804. In some embodiments, the coil-reinforced tube 1802 may have a hole aligned with the guidewire port. In some embodiments, the coil -reinforced tube 1802 may include a first tube and a second tube with a space therebetween that aligns with the guidewire port. The base tube 1804 may include inlet openings 1827 cut into a distal tubular section between the tube section 1820 and the distal connection section 1822.

[0182] In some embodiments the inlet tube 1800 is connected, via the proximal connection section 1821, to an impeller cage 704. The impeller cage 704 can include outlet openings 1828. In some embodiments, the inlet tube 1800 is connected, via the proximal connection section 1821, directly to a motor housing. In some embodiments the inlet tube 1800 is directly connected to the motor housing and includes impeller housing features such as outlet openings cut into the base tube.

[0183] The electrical conducting element 1806 may include some or all of the features of the electrical conducting device described herein. These features can include alignment features, sensors or sensor mounts, and / or radiopaque markers. The electrical conducting element 1806 may have a ribbon shape with a width greater than thickness. The electrical conducting element 1806 may be attached (e.g. via adhesive, dip coating, over molding) to the base tube 1804 along the helical mounting surface 1823 of the tube section 1820. The mounting of the electrical conducting element 1806 to the helical mounting surface 1823 can facilitate movement of the helical mounting surface and / or electrical conducting element 1806 when the inlet tube 1800 flexes without causing strain to the electrical conducting element 1806. In some embodiments, the coil 1808 in the coil-reinforced tube 1802 may include an electrical conductor, in addition or alternative to the conductors on the electrical conducting element 1806.

[0184] In some embodiments, an external polymer layer may be added on the outer surface of the electrical conducting element 1806 to bind it to the base tube 1804 and / or the coil-reinforced tube 1802. In some embodiments, the external polymer layer may include the coil-reinforced tube 1802 disclosed herein in various embodiments. In some embodiments, the external polymer layer may be a thin (e.g., <0.05mm) layer of material that is applied (e.g., heat shrunk, dip coated, over molded) to the external side of the electrical conducting element 1806.Electrical Conducting Element Features

[0185] A cardiac assist system may include an electrical conducting element (e.g., a flexible printed circuit board (flex PCB)). The electrical conducting element can provide a reliable and flexible means of electrically connecting various sensors and electronics on the guide cannula. The electrical conducting element can include several locating featuresdesigned to ensure proper alignment and secure attachment to a sheath of a guide cannula. These locating features can ensure that the electrical conducting element is correctly positioned and securely attached to the guide cannula to facilitate proper electrical connections. Additionally, the arrangement of the electrical conducting element may eliminate the need for tight, sharp bends which can compromise the structural integrity and strength of the electrical conducting element, thereby facilitating an easy to assemble and structurally robust cardiac assist system.Example Assist Device Embodiments

[0186] FIG. 21 shows a guide cannula 101 of a cardiac assist device 100 (e.g., a left ventricle assist device). The cardiac assist device 100 can be a component of a mechanical circulatory support (MCS) system and / or a cardiac assist system. The guide cannula 101 includes a distal region 123 and a proximal region 121. The guide cannula 101 serves as a conduit for blood flow within the cardiac assist device 100. The cardiac assist device 100 can include one or more of the following: a distal tip 126, inlet openings 129, the guide cannula 101, outlet openings 128, a motor housing 115, an electrical conducting element 180, a proximal cap 220, and a connection cable 290 configured to mechanically and electrically connect to other components of a cardiac assist system.

[0187] An inlet tube 120 forms the main body of the guide cannula 101. The inlet tube 120 is designed to be flexible yet durable, allowing the inlet tube 120 to navigate through the vascular system. The inlet tube 120 is typically made from biocompatible materials such as polyimide, silicone or polyurethane, reinforced with a structural material such as Nitinol or stainless steel, which provide the necessary flexibility and strength to withstand the mechanical stresses encountered during insertion and operation. These materials ensure that the inlet tube 120 can bend and flex without compromising its structural integrity or the functionality of the cardiac assist system.

[0188] The inlet tube 120 features helical slots 136, which are laser cut into the material to enhance its flexibility. These helical slots 136 allow the inlet tube 120 to bend and flex while maintaining its structural integrity. The helical arrangement of the slots 136 ensures that the inlet tube 120 can navigate through the vascular system with ease, accommodating thenatural curves and bends of the blood vessels. The precise positioning of the slots 136 provides optimal flexibility without compromising the radial strength of the inlet tube 120.

[0189] The distal region 123 of the guide cannula 101 features a distal tip (e.g., a sensor head unit) 126. The distal tip 126 is positioned at a distal end of the inlet tube 120. The distal tip 126 provides an atraumatic surface to minimize damage to the heart tissue during insertion and operation. The distal tip 126 is designed to facilitate the smooth entry of the guide cannula 101 into the vascular system. Additionally, the distal tip 126 can include sensors, such as pressure and temperature sensors, or ultrasound transducer(s) to monitor various parameters within the heart or MCS device.

[0190] An electrical conducting element 180 can couple to the inlet tube 120 to electrically connect components in the proximal region 121 with one or more electrically connected components in the distal region 123, such as one or more sensors located on or in the distal tip 126, or components along the length of the inlet tube between the proximal and distal ends. The electrical conducting element 180 can be helically wound around the inlet tube 120 traversing from the distal region 123 to the proximal region 121 across the length of the inlet tube 120. The electrical conducting element 180 is configured to contact at least one sensor within the cardiac assist system. The electrical conducting element 180 can electrically connect to sensors, transducers, or electrical elements in or on the distal tip 126. The electrical conducting element 180 can enable the monitoring and adjustment of the cardiac assist system's performance. The electrical conducting element 180 is designed to provide electrical connectivity while maintaining flexibility and durability.

[0191] Adjacent to the distal tip 126, the guide cannula 101 includes a plurality of inlet openings 129. The inlet openings 129 allow blood to enter the guide cannula 101. These openings are strategically positioned to ensure efficient blood flow into the guide cannula 101. The inlet openings 129 are supported by inlet struts 133 and can be formed into the inlet tube 120 which forms the main body of the guide cannula 101. In some embodiments, the inlet openings 129 are integral to the inlet tube 120. In some embodiments, the inlet openings 129 are attached to the inlet tube 120 with a connecting element which includes a plurality of inlet openings separated by a plurality of inlet struts.

[0192] Moving proximally from the inlet openings 129, the guide cannula 101 includes a guidewire port 134. The guidewire port 134 is positioned between the distal region123 and the proximal region 121, for example, approximately at a midpoint in the inlet tube 120. The guidewire port 134 is an opening in the inlet tube 120 that allows for the passage of a guidewire, facilitating the navigation and placement of the guide cannula 101 within the vascular system. The guidewire port region 135 surrounds the guidewire port 134 and includes specific features to assist in the alignment and positioning of the electrical conducting element 180. The guidewire port region 135 in some embodiments can be a region free of helical slots 136. The guidewire port 134 can be located distal to the impeller such that a guidewire can enter the guide cannula 101 through the distal tip 126 and extend out of the guide cannula 101 through the guidewire port 134, preventing the guidewire from contacting the impeller.

[0193] Further proximally, the guide cannula 101 features a plurality of outlet openings 128. The outlet openings 128 are positioned near a motor housing 115 and are separated by outlet struts 138. A strut 138 is positioned between each outlet opening 128 and the adjacent outlet opening 128. The struts 138 connect the inlet tube 120 to the motor housing 115. Each strut 138 is strategically placed between two outlet openings 128 to maintain the alignment and structural integrity of the outlet openings 128 during operation. The outlet openings 128 allow blood to be discharged from the guide cannula 101 into the cardiovascular system. In some embodiments, the outlet struts 138 are integral to the inlet tube 120. In some embodiments, the outlet struts 138 are attached to the inlet tube by a connecting element. The outlet openings 128 can be openings in an impeller cage 137, illustrated in detail in FIG. 22F, which attaches to the inlet tube 120 by a connecting element.

[0194] The motor housing 115 is positioned at the proximal region 121 of the guide cannula 101. The motor housing 115 contains a motor that drives an impeller of the cardiac assist system. The impeller facilitates the pumping of blood through the inlet openings 129, which is then transported through the inlet tube 120 towards the plurality of outlet openings 128. The outlet openings 128, positioned near the motor housing 115, discharge the blood into the cardiovascular system (e.g. the aorta).

[0195] A proximal cap (e g., end unit) 220 is located adjacent to and proximal from the motor housing 115 in the cardiac assist device 100. The proximal cap 220 houses an electronics module and provides structural support for the electrical conducting element 180. The proximal cap 220 includes an opening through which the electrical conducting element 180 passes, ensuring proper alignment and secure attachment. The proximal cap 220 of theguide cannula 101 may include one or more sensors that play a role in monitoring and controlling the cardiac assist system. These sensors are strategically positioned within the proximal cap 220 to ensure accurate data collection and reliable performance. The sensors integrated into the proximal cap 220 can include one or more pressure sensors, temperature sensors, and / or impedance sensors, among others. Each sensor may be connected to the electrical conducting element 180, which transmits the collected data to the electronics module for analysis and real-time adjustments, or can be connected to the system by a separate electrical connection within the proximal cap 220. There can be a void proximal from the motor housing 115 within the proximal cap 220.

[0196] A connection cable 290 is sufficiently long to connect the cardiac assist system positioned in the heart to any extracorporeal device, such as a computerized console positioned extracorporeally, by passing through the patient's vasculature (e.g., aorta to femoral artery or axillary artery). The extracorporeal device can connect to the electronics module and communicate with the electrical conducting element 180. The connection cable 290 may include conductors for providing power to the motor and impeller, and / or communicating with sensors (e.g., such as pressure, temperature, impedance, ultrasound sensors).

[0197] FIG. 22A shows a view of an inlet tube 120, illustrating the helically wound electrical conducting element 180. The inlet tube 120 forms the main body of the guide cannula 101 and provides structural support. The inlet tube 120 is designed to be flexible yet durable, allowing the guide cannula 101 to navigate through the vascular system.

[0198] The distal region 123 of the inlet tube 120 features a plurality of inlet openings 129, which allow blood to enter the guide cannula 101. The inlet openings 129 are positioned around the distal region 123 and are defined by inlet struts 133. The inlet struts 133 provide structural support and ensure the alignment of the inlet openings 129.

[0199] The electrical conducting element 180 is helically wound around the inlet tube 120, following a pattern (e.g. angular pathway) of helical slots 136 formed into the inlet tube 120. The helical slots 136 provide flexibility to the guide cannula 101, allowing the guide cannula 101 to bend and flex while maintaining structural integrity. The electrical conducting element 180 may be aligned with these helical slots 136, such that the electrical conducting element 180 can flex and bend along with the guide cannula 101 without experiencing damageor misalignment. The electrical conducting element 180 may be positioned between the helical slots 136 and attached to the inlet tube 120.

[0200] A guidewire port 134 is located in the guidewire port region 135 of the inlet tube 120, approximately at the midpoint of the inlet tube 120. The guidewire port region 135 can include one or more features to assist in the alignment and positioning of the electrical conducting element 180, as will be described in greater detail. In some embodiments, the guidewire port 134 may be positioned more distally or more proximally along the length of the inlet tube 120 depending on the shape of the guide cannula 101. In some embodiments, a guidewire port may be positioned adjacent to the outlet openings (e.g. within 10mm distal to the outlet openings).

[0201] The electrical conducting element 180 may also include features to ensure proper alignment and secure attachment to the inlet tube. For example, distal alignment indicators 189 can be positioned at intervals along the distal region 123 of the length of the electrical conducting element 180. These distal alignment indicators 189 assist in the accurate placement of the electrical conducting element 180 on the inlet tube 120 during the manufacturing process. The distal alignment indicators 189 may be visually distinct features that align with corresponding features (e.g., guide indicators) on the inlet tube 120, such as the spaces (e.g. helical interruptions) between the helical slots 136 or laser etchings on the inlet tube 120. Proximal alignment indicators 190 are positioned at intervals along the proximal region 121 of the length of the electrical conducting element 180. These proximal alignment indicators 190 assist in the accurate placement of the electrical conducting element 180 on the inlet tube 120 during the manufacturing process. The proximal alignment indicators 190 may be visually distinct features that align with corresponding features (e.g., guide indicators) on the inlet tube 120, such as the spaces (e.g. helical interruptions) between the helical slots 136 or laser etchings on the inlet tube 120.

[0202] The electrical conducting element 180 can also include a distal straight portion 187, which extends past the inlet openings 129 along one of the inlet struts 133. A bend 191 facilitates the transition from the helical winding to the distal straight portion 187. In the guidewire port region 135, the electrical conducting element 180 can include a first bend 192, a second bend 193, and a tolerance section 194. The electrical conducting element 180 transitions into a proximal straight portion 188 at the proximal region 121 of the guide cannula101. This proximal straight portion 188 ensures that the electrical conducting element 180 can be securely attached to the proximal region 121, for example along an outlet strut 138, maintaining proper alignment and electrical connectivity.

[0203] FIG. 22B shows a detailed view of a portion of a guide cannula 101. The figure illustrates a guidewire port region 135 located in an intermediate position between the proximal end and distal end of the inlet tube 120 of the guide cannula 101. The guidewire port region 135 may be located in a section of the inlet tube 120 that is free of helical slots. This region may ensure sufficient space for the alignment of electrical conducting element 180 relative to the guide cannula 101 while maintaining the structural integrity of the inlet tube 120.

[0204] The electrical conducting element 180 is helically wound around the inlet tube 120. In the guidewire port region 135, the electrical conducting element 180 includes a first bend 192, a second bend 193, and a tolerance section 194. These bends 192, 193 may facilitate the placement of the electrical conducting element 180 by allowing for adjustment during the manufacturing process. The first bend 192 facilitates aligning the tolerance section 194 approximately lengthwise with the inlet tube 120 rather than helically wound. The second bend 193 facilitates a transition from the lengthwise tolerance section 194 back to the helically wound arrangement. The first bend 192 and the second bend 193 are designed to accommodate the curvature of the inlet tube 120, ensuring that the electrical conducting element 180 can be accurately positioned along the length of the guide cannula 101. For example, the angles of the first bend 192 and second bend 193 can be adjusted or the length and / or angular orientation of the tolerance section 194 can be adjusted during attachment of the electrical conducting element 180 to accommodate any variation in the size or shape of the components of the guide cannula 101 and / or to accommodate variation in the length of the electrical conducting element 180. In some embodiments, the angles of the bends 192, 193 may range from 90 degrees to 120 degrees, depending on the specific curvature requirements of the inlet tube 120. In some embodiments, the angles of the bends 192, 193 may range from 70 to 150 degrees. For example, the angles of the bends 192, 193 in the electrical conducting element 180 can be, or can be about 70 degrees, 75 degrees, 80 degrees, 85 degrees, 90 degrees, 95 degrees, 100 degrees, 105 degrees, 110 degrees, 115 degrees, or 120 degrees, 125 degrees, 130 degrees, 135 degrees, 140 degrees, 145 degrees, or 150 degrees or any intermediate value therebetween.These angles allow the electrical conducting element 180 to conform to the contours of the inlet tube 120 without compromising the structural integrity or electrical connectivity of the electrical conducting element 180.

[0205] The tolerance section 194, located between the first bend 192 and the second bend 193, provides additional flexibility for the electrical conducting element 180. This section allows for minor adjustments to be made during the assembly process, ensuring that the electrical conducting element 180 aligns correctly with the guidewire port region 135 and other features of the inlet tube 120. The design of the bends and the tolerance section 194 ensures that the electrical conducting element 180 maintains structural integrity while providing the necessary electrical connectivity for the cardiac assist system. In some embodiments, the length of the tolerance section 194 in the electrical conducting element 180 can be between 3mm and 10mm. For example, the length of the tolerance section 194 can be, or can be about 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, or any intermediate value therebetween. These lengths provide sufficient flexibility to accommodate variations in the manufacturing process and ensure proper alignment of the electrical conducting element 180 on the guidewire port region 135 and other features of the inlet tube 120. Other lengths of the tolerance section 194 can equally be implemented, depending on the size and geometry of the inlet tube 120 to which the electrical conducting element is being applied.

[0206] FIG. 22C shows a detailed view of a portion of a guide cannula 101 including the inlet openings 129 and a plurality of inlet opening struts 133. As illustrated, an inlet strut 133 is positioned between two of the inlet openings 129. The inlet strut 133 provides structural support to the guide cannula 101 and ensures the alignment of the inlet openings 129.

[0207] The electrical conducting element 180 traverses the inlet strut 133 to attach to the distal tip 126 (FIG. 21) of the guide cannula 101. The inlet strut 133, positioned between two inlet openings 129, provides structural support and ensures the alignment of the inlet openings 129. The electrical conducting element 180 transitions from a helically wound arrangement around the inlet tube 120 to a distal straight portion 187 that extends along the inlet strut 133. This configuration allows the electrical conducting element 180 to extend distally past the inlet openings 129, ensuring proper alignment and connectivity. In some embodiments, the inlet strut 133 includes a longitudinal channel or recess which the distalstraight portion 187 of the electrical conducting element 180 can sit within. The channel may have a depth approximately the same as the thickness of the electrical conducting element 180. In some embodiments, the inlet strut 133 may include a rough surface finish to facilitate adherence of the electrical conducting element 180 to the inlet strut 133.

[0208] The bend 191 in the electrical conducting element 180 facilitates the transition from the helical winding to the distal straight portion 187. The bend 191 is designed to accommodate the curvature of the guide cannula 101, ensuring that the electrical conducting element 180 can be accurately positioned along the length of the guide cannula 101 without compromising structural integrity or electrical connectivity. The distal straight portion 187 of the electrical conducting element 180 can run parallel to the longitudinal axis of the guide cannula 101 along the surface of the inlet strut 133, providing a pathway spanning the inlet openings 129 for electrical signals. Advantageously, the inlet strut 133 can provide a supporting structure for the electrical conducting element 180 to span the inlet openings 129.

[0209] At the distal tip (e.g., sensor head unit) 126 (FIG. 21), the electrical conducting element 180 may attach to various sensors, such as pressure and / or temperature sensors, integrated into the distal tip 126. The electrical conducting element 180 ensures reliable electrical connectivity between the sensors in the distal tip 126 and the electronics module in the proximal region 121 of the guide cannula 101. This configuration enables the monitoring and adjustment of the cardiac assist system's performance, ensuring optimal functionality and patient safety.

[0210] FIG. 22D and 22E illustrate detailed views of the alignment features of the electrical conducting element 180 in the guidewire port region 135 of the inlet tube 120. FIG. 22D depicts an intermediate region of the guide cannula 101 including the guidewire port region 135. FIG. 22E is a detailed view of the region of an individual alignment feature. The distal alignment indicators 189 and proximal alignment indicators 190, along with the bends 192, 193 and the tolerance section 194, facilitate the proper placement and secure attachment of the electrical conducting element 180, which further promotes the effective operation of the cardiac assist system. The guidewire port region 135 is the area surrounding the guidewire port 134, which may include specific features to assist in the alignment and positioning of the electrical conducting element 180.

[0211] The electrical conducting element 180 can be helically wound around the inlet tube 120, following the pattern of the helical slots 136, for example having the same helical angle as the helical slots. The proximal alignment indicators 190 are positioned at intervals along the length of the electrical conducting element 180. These proximal alignment indicators 190 are designed to align with corresponding features on the inlet tube 120, such as the spaces along the helical path between the ends of two adjacent helical slots 136, which act as guide indicators and ensure that the electrical conducting element 180 is correctly positioned and securely attached. The proximal alignment indicators 190 may be visually distinct features, such as tabs or notches or visible markings, that align with corresponding features on the inlet tube 120. For example, as shown in FIG. 22E, an alignment indicator such as proximal alignment indicator 190 is configured to be disposed between the lengthwise ends of helical slot 136a and helical slot 136b. In this configuration, the proper alignment of the proximal alignment indicator 190 between the ends of helical slots 136a and 136b can be quickly and reliably confirmed visually. This alignment ensures that the electrical conducting element 180 is correctly positioned, allowing for proper electrical connections and optimal performance of the cardiac assist system.

[0212] The first bend 192 and the second bend 193 in the electrical conducting element 180 facilitate its alignment with the inlet tube 120, as discussed in detail with reference to FIG. 22A. These bends are designed to accommodate the natural curves and bends of the inlet tube 120, ensuring that the electrical conducting element 180 remains properly aligned and securely attached. The tolerance section 194, located between the first bend 192 and the second bend 193, provides additional flexibility, allowing for minor adjustments during the assembly process to ensure proper alignment with the guidewire port region 135. These minor adjustments can be made quickly and efficiently due to the proximal alignment indicators 190 by aligning the proximal alignment indicators 190 with the locating features on the inlet tube 120 via adjustments to the tolerance section 194, first bend 192, and second bend 193.

[0213] FIG. 22F shows a detailed view of the proximal end of a guide cannula, illustrating the arrangement in which the electrical conducting element 180 traverses an outlet strut 138 to attach to the electronics module of the cardiac assist system. The outlet strut 138 can be a component of an impeller cage 137. The impeller cage 137 can be integrally formed with the inlet tube 120. In some examples, the impeller cage 137 can attach to the inlet tube120. The electrical conducting element 180 includes a proximal straight portion 188, which extends along the outlet strut 138. Alternatively, if the outlet strut 138 is not straight, the electrical conducting element 180 may include a portion having a similar shape as the outlet strut allowing it to be positioned and connected to the outlet strut. The proximal straight portion 188 ensures that the electrical conducting element 180 can be securely attached to the inlet tube 120, maintaining proper alignment and electrical connectivity. The proximal straight portion 188 is designed to provide a pathway spanning the outlet openings 139 for electrical signals, ensuring reliable connectivity between the sensors and the electronics module of the cardiac assist system. Advantageously, the outlet strut 138 can provide a supporting structure for the electrical conducting element 180 to span the outlet openings 139 of the impeller cage137. The electrical conducting element 180 also includes a bend 196, which facilitates the transition from the helical winding to the proximal straight portion 188. In some embodiments, the outlet strut 138 includes a channel which the electrical conducting element 180 can sit within. The channel may have a depth approximately the same as the thickness of the electrical conducting element 180. In some embodiments, the outlet strut 138 may include a rough surface finish to facilitate adherence of the electrical conducting element 180 to the outlet strut138.

[0214] FIG. 23 shows an example implementation of the electrical conducting element 180 in a manufacturing configuration prior to being wrapped around a guide cannula 101 or other device. The electrical conducting element 180 includes multiple components and features that facilitate the integration and functionality of the electrical conducting element 180, as described elsewhere herein. In the example electrical conducting element of FIG. 23, the electrical conducting element 180 comprises multiple layers, including a substrate layer, electrical traces, and a dielectric layer. Throughout the description of FIG. 23, reference will also be made to components illustrated in FIGS. 21-22F. Other configurations of an electrical conducting element 180, such as those having more or fewer components than those described with reference to FIG. 23, can similarly be implemented in conjunction with the disclosed cardiac assist systems.

[0215] The substrate layer of the electrical conducting element 180 provides the foundational support, allowing the element to bend and flex along with the inlet tube 120. This layer can be made from a flexible, durable material such as polyimide, which can withstandthe mechanical stresses encountered during insertion and operation within the cardiovascular environment. The flexibility of the substrate layer ensures that the electrical conducting element 180 can conform to the contours of the inlet tube 120 and maintain its alignment throughout the length of the guide cannula 101.

[0216] The electrical traces are deposited on or otherwise applied to the substrate layer and form the conductive pathways that transmit electrical signals between the sensors and the electronics module. These traces can be made from a conductive material such as copper, which provides excellent electrical conductivity and reliability. The electrical traces can be arranged in a pattern that ensures efficient signal transmission while reducing the risk of interference or signal loss.

[0217] The dielectric layer insulates the electrical traces, preventing short circuits and ensuring reliable signal transmission. This layer can be made from a non-conductive material such as polyimide or polyester, which provides desirable insulation properties while maintaining the flexibility of the electrical conducting element 180. The dielectric layer also protects the electrical traces from environmental factors such as moisture and temperature fluctuations, improving the long-term reliability of the electrical conducting element 180.

[0218] In some embodiments, one or more layers (e.g., the dielectric layer and / or the substrate layer can be formed from a thermoplastic polymer for example a liquid crystal polymer (LCP). Advantageously, the thermoplastic polymer may facilitate improved fusing and reduced delamination between the layers of the electrical conducting element 180 and improve the attachment of the electrical conducting element 180 to the guide cannula 101.

[0219] A micro connector 186 can be positioned on a distal micro connector pad 198 at the distal end of the electrical conducting element 180 in the distal straight portion 187. A detailed view of a distal micro connector pad 198 can be seen in Detail P of FIG. 23. The micro connector 186 facilitates the connection of the electrical conducting element 180 to other components of the cardiac assist system such as sensors, transducers or other electrical elements, ensuring reliable electrical connectivity. The electrical conducting element 180 includes a distal bend 191, which facilitates the transition from the helical winding to the distal straight portion 187. The portion of the electrical conducting element 180 to be helically wound includes one or more distal alignment indicators 189 positioned at intervals along the length of the distal region of the electrical conducting element 180. A first bend 192, a tolerancesection 194, and a second bend 193 are located at an intermediate portion, such as near the midpoint, of the electrical conducting element 180. The portion of the electrical conducting element 180 to be helically wound includes one or more proximal alignment indicators 190 positioned at intervals along the length of the proximal region of the electrical conducting element 180. The electrical conducting element 180 includes a proximal bend 196, which facilitates the transition from the helical winding to a proximal straight portion 188. A micro connector 181 is positioned on a proximal micro connector pad 197 at the proximal end of the electrical conducting element 180, which serves as an interface for connecting the electrical conducting element 180 to other components of the cardiac assist system. A detailed view of a proximal micro connector pad 197 can be seen in Detail Q of FIG. 23. The micro connector pad 197 and the distal micro connector pad 198 are integrated into the electrical conducting element 180. These pads provide secure attachment points for the micro connectors, ensuring reliable electrical connections within the cardiac assist system.

[0220] Detail M illustrates the proximal end of the electrical conducting element 180, which may include one or more proximal sensors 183. The proximal sensors 183 can be positioned on a micro connector pad 195, which provides a secure attachment point for the sensors, ensuring reliable electrical connections within the cardiac assist system. These sensors are positioned near the proximal region 121 of the guide cannula 101. The proximal sensors 183 are connected to the electrical traces within the electrical conducting element 180, allowing the sensors to transmit data to the electronics module for analysis and monitoring. The proximal sensors 183 may include various types of sensors, such as pressure sensors, temperature sensors, or impedance sensors, or ultrasound transducer(s). By monitoring parameters such as pressure, temperature, and impedance, the proximal sensors 183 provide real-time data that can be used to adjust the operation of the cardiac assist system or assess a condition of the patient. This ensures that the system operates efficiently and effectively, providing the necessary support to the cardiovascular system while minimizing the risk of complications.

[0221] Detail Q shows the proximal plug of the electrical conducting element 180, including the proximal micro connector 181 positioned on the micro connector pad 197. The micro connector 181 facilitates the connection of the electrical conducting element 180 to other components of the cardiac assist system, ensuring reliable electrical connectivity. The microconnector 181 is configured to interface with the proximal sensors 183 and other electronic components to the electronics module. In some embodiments, the position of the connector 181 and the sensor 183 illustrated in detail views Q and M may be reversed such that the sensor 183 is on a proximal end of the electrical conducting element 180 and the connector 181 is positioned distal from the sensor 183.

[0222] Detail P shows a detailed view of the distal region 123 of the electrical conducting element 180, including a micro connector 186 positioned on the distal micro connector pad 198. The distal micro connector pad 198 provides a secure attachment point for the distal micro connector 186, ensuring that the electrical connections are stable and reliable. The distal micro connector pad 198 is designed to align with the corresponding features on the distal tip, facilitating the accurate placement and secure attachment of the distal micro connector 186.

[0223] FIGS. 24 and 25 illustrate the proximal end of a cardiac assist device, including the arrangement of the electrical conducting element 180 traversing around the electronics module 250 within the proximal cap 220. FIG. 24 is a cross-sectional view taken about a longitudinal axis of the cardiac assist device. FIG. 25 is a perspective view in which the proximal cap 220 has been removed to illustrate interior components. As shown in FIGS. 24 and 25, the electrical conducting element 180 wraps around the proximal end of the electronics module 250. As will be described in greater detail, the arrangement of the electrical conducting element 180 advantageously allows the electrical conducting element 180 to pass into and around the interior of the proximal cap 220 without any sharp bends which might facilitate breakage, and allows for flexibility in the positioning of the electrical conducting element 180.

[0224] The electrical conducting element 180 features several bends, including bend 184 and bend 185, which can allow for flexibility in the positioning of the electrical conducting element 180. Advantageously, the bends 184 and 185 allow for flexibility in the positioning of the electrical conducting element 180 which facilitates accurate alignment of components such as the micro connector 181 to a mating micro connector 182 without component tolerance and manufacturing steps preventing accurate alignment. The bends 184 and 185 further enhance the flexibility and alignment of the electrical conducting element 180. These bends allows the electrical conducting element 180 to navigate around the electronicsmodule 250 within the proximal cap 220, ensuring that the electrical connections remain intact and free from mechanical stress. The bends 184 and 185 are located in the void proximal from the motor housing 115 in the proximal cap 220 and provide additional flexibility, allowing for minor adjustments during the assembly process to ensure proper alignment with the electronics module 250 and other components of the cardiac assist system. For example, bend 184 is located within an open region such that it can move to create additional tolerance in the length of the proximal portion of the electrical conducting element 180. The bends 184, 185 may include slack in the electrical conducting element 180 to accommodate mismatches (for example, manufacturing tolerance stack up) between the length of the electrical conducting element 180 and the length of the path of the MCS device along which the electrical conducting element 180 is located.

[0225] The design of bends 184 and 185 also contributes to the overall durability and longevity of the cardiac assist system. By securely wrapping around the inlet tube 120 and the electronics module 250, the electrical conducting element 180 is less likely to experience wear and tear from movement or vibration during operation. This stability reduces the likelihood of electrical failures or disconnections, contributing to the overall reliability and safety of the cardiac assist system. The bends also allow for better management of tolerances, ensuring that the electrical conducting element 180 remains properly aligned and connected throughout manufacturing process at both component manufacturing and assembly steps.

[0226] The proximal cap 220 houses the electronics module 250. The proximal cap 220 includes an opening 221 through which the electrical conducting element 180 passes, ensuring proper alignment and secure attachment. A sealant may be applied around the conducting element 180 in opening 221 to prevent blood from entering the interior of the proximal cap 220. In embodiments in which one or more proximal sensors are included, the proximal cap 220 can also include a sensor window 222, which allows the proximal sensor 183 to monitor parameters within the cardiac assist system or in the patient. The electronics module 250 is positioned within the proximal cap 220 and is connected to the electrical conducting element 180. The electronics module 250 connects electrical components of the motor within motor housing 115 to conductors in the connection cable 290.

[0227] A micro connector 181 may be positioned at or near the proximal end of the electrical conducting element 180. The micro connector 181 facilitates the connection of theelectrical conducting element 180 to other components of the cardiac assist system such as conductors in the connection cable 290 that communicate with an extracorporeal controller, ensuring reliable electrical connectivity. The mating micro connector 182 is integrated into the micro connector pad 197 of the electrical conducting element 180, providing a secure attachment point for the micro connector 181.

[0228] The proximal sensor 183 is integrated into the electrical conducting element 180 near the connector 181. The proximal sensor 183 monitors various parameters within the cardiac assist system or patient and transmits data to the extracorporeal controller. The proximal sensor 183 is connected to the electrical traces within the electrical conducting element 180, ensuring efficient signal transmission.

[0229] The cardiac assist device 100 can include one or more distal sensors, such as at the distal region 123 of the cardiac assist device 100. The cardiac assist device 100 can include one or more proximal sensors 183, such as at the proximal region 121 of the cardiac assist device 100 or along the length of the device 100. The electrical conducting element 180 can provide electrical communication between both the distal sensors and proximal sensors 183 and the extracorporeal controller via the micro connector 181 in the configuration shown in FIGS. 24 and 25.Electrode Integration for Bioimpedance Measurement

[0230] Impedance in the heart or a chamber of the heart such as the left ventricle can be measured to deduce the volume of blood in the heart or chamber and subsequently derive the native cardiac output (e.g., output of the left ventricle to the aorta). The measurement may be done by using two electrodes which provide an alternating current into surrounding blood and measuring the resulting voltage drop with two additional electrodes. Ideally the two pairs of electrodes can be spaced as far apart as the measurement range will allow (e.g., as far apart as the measurement device or cavity will allow) while each electrode within a pair are close together, for example in a range of 0.5 to 5 mm or more. For example, the current providing electrode pair may be positioned on a guide cannula that is in turn positioned in a distal area of a left ventricle, such as on the distal tip of the guide cannula and the voltage measuring electrode pair may be positioned on the guide cannula that is in turn positioned in a relatively proximal area of the left ventricle. The pairs of electrodes can be spaced apart, forexample, in a rage from 50mm to 80mm apart from the current providing pair to the voltage measuring pair. In various embodiments, the two electrode pairs can be less than 50mm apart, or can be greater than 80mm apart. Alternatively, a similar arrangement may be applied but with the current providing electrode pair positioned at a proximal region of the ventricle (e.g., on an inlet tube near its proximal end) and the voltage measuring electrode pair positioned at a distal region of the ventricle (e.g., on a distal tip of the medical device or on the inlet tube near its distal end). To increase or maximize surface area of the electrodes, in some embodiments some or all of the electrodes may wrap around the whole circumference of the medical device, may wrap around a portion less than half of the circumference, or 50% or a majority of the circumference (e.g., 50%, 60%, 70%, 80%, or 90% of the circumference, or any percentage therebetween).

[0231] FIGS. 26-29 illustrate various example implementations of electrodes for measuring bioimpedance using the electrical conducting elements described herein. The electrical conducting element transmits each electrode signal to the to the extracorporeal controller for analysis. Accordingly, the electrical conducting element can be equipped with connection features (e g., solder pads or micro connectors) to attach distinct conductor lines in the electrical conducting element to the individual electrodes. The electrical conducting element can attach to the guide cannula or other medical device structure as described elsewhere herein.

[0232] A cable can connect the cardiac assist system positioned in the heart to a computing device positioned extracorporeally by passing through the patient's vasculature (e.g., aorta to femoral artery or axillary artery). Additionally, or alternatively, the cardiac assist system can communicate wirelessly with the computing device. The computing device can communicate with the electrical conducting element. The computing device may further include a current delivering circuit for delivering current to the current providing electrode(s), and a voltage measuring circuit for receiving voltage signals from the voltage capturing electrodes.

[0233] FIG. 26 shows an arrangement of electrodes on an electrical conducting element 280 for a cardiac assist system. The figure illustrates the implementation and positioning of various components for bioimpedance measurement within the system. The electrical conducting element 280 may be, for example, the electrical conducting element 180described above with reference to FIGS. 21-25. The electrodes described below in connection with the electrical conducting element 280 may be provided instead of or in addition to any of the various sensors described in connection with electrical conducting element 180.

[0234] A first pair of electrode connectors 220A-1 and 220A-2 are positioned at the distal end or region of the electrical conducting element 280. The first pair of electrode connectors 220 A- 1 and 220A-2 can serve as an interface for connecting a pair of electrodes 210A-1 and 210A-2 to the electrical conducting element 280. This connection ensures reliable electrical pathways for transmitting signals between the electrodes and the electronics module of the cardiac assist system.

[0235] A second pair of electrode connectors 220B-1 and 220B-2 are positioned proximal from the first pair of electrode connectors 220A-1 and 220A-2. The second pair of electrode connectors 220B-a and 220B-2 can serve as an interface for connecting a pair of electrodes 210B-1 and 210B-2 to the electrical conducting element 280.

[0236] The two pairs of electrodes, 210A-1 and 210A-2, and 210B-1 and 21 OB-2 are part of the bioimpedance measurement functionality of the cardiac assist system. The first pair of electrode pads 210A-1 and 210A-2 are positioned at a distal region 123 of the guide cannula 101, while the second pair of electrode pads 210B-1 and 21 OB-2 are located at a more proximal region 121. This placement ensures that the electrodes are positioned within the left ventricle when the guide cannula 101 is correctly deployed. The second pair of electrode pads is positioned at a more proximal region of the guide cannula 101, typically near the proximal region 121. This placement ensures that the second pair of electrode pads is located within the aorta when the guide cannula 101 is correctly positioned.

[0237] The integration of the first and second pairs of electrode pads 210A-1 and 210A-2, and 210B-1 and 210B-2 into the electrical conducting element 180 allows for comprehensive bioimpedance measurements across different regions of the heart. By measuring the impedance at both the distal region 123 and proximal region 121, the system can provide detailed data on the volume of blood in the heart or a chamber of the heart, which is useful for assessing cardiac function and adjusting the operation of the cardiac assist system in real-time.

[0238] FIG. 27 shows an example implementation of electrode pads for a cardiac assist system. The figure illustrates a configuration of multiple electrode pads integrated intoan electrical conducting element 380, which is designed as a four-wire micro ribbon cable. The electrical conducting element 380 provides electrical connectivity within the cardiac assist system, facilitating bioimpedance measurements. A first pair of electrode pads 310A-1 and 310A-2 are located in a distal region 123 of the electrical conducting element 380 and a second pair of electrode pads 310B-1 and 310B-2 are located in a more proximal region 121 of the electrical conducting element. Each electrode is positioned on a separate wire of the four-wire ribbon cable. Each of the electrode pads 310A-1, 310A-2, 310B-1, and 310B-2 provides a secure attachment point for electrodes, ensuring stable and reliable electrical connections. The electrode pads 310A-1, 310A-2, 310B-1, and 310B-2 are designed to hold the electrodes in place, maintaining their alignment and connectivity during the operation of the cardiac assist system. In some examples, the four-ribbon cable can be a portion, or one layer of an electrical conducting element 180. In some examples, the electrical conducting element 180 include additional wires which can carry signals and / or connect to different elements of the cardiac assist device.

[0239] FIG. 28 shows an electrical conducting element 480 with a pair of electrode pads 410-1 and 410-2 in a flat, uninstalled configuration, for example in the form of a flex PCB. The electrical conducting element 480 can also include a second pair of electrode pads as described in FIGS. 26 and 27. The electrical conducting element 480 is designed to provide electrical connectivity within a cardiac assist system, facilitating bioimpedance measurements.

[0240] The electrode pads 410-1 and 410-2 are positioned along the length of the electrical conducting element 480. Each electrode pad 410-1 and 410-2 provides a secure attachment point for electrodes. Each electrode pad 410-1 and 410-2 may be electrically continuous with conducting element 480 (e.g. formed as an electrical trace in a flex PCB manufacturing process), ensuring stable and reliable electrical connections. The electrode pads 410-1 and 410-2 are designed to hold the electrodes in place, maintaining their alignment and connectivity during the operation of the cardiac assist system.

[0241] The electrode pads 410-1 and 410-2 may attach to electrodes in the form of metal rings or clamps that are positioned around the circumference of the inlet tube. These metal rings or clamps are connected to the processed surface of the electrode pads, providing a robust and reliable method for securing the electrodes. This configuration ensures that the electrodes remain securely attached to the electrical conducting element 480, even under themechanical stresses encountered during insertion and operation within the cardiovascular environment. Alternatively, the electrodes may be formed as integral parts of a flex PCB that are continuous with the conducting element 480 without intermediary electrode pads.

[0242] FIG. 29 shows a view of a guide cannula 101, focusing on a segmented distal tip 126 and inlet tube 120. In this example implementation, the distal tip 126 of the guide cannula 101 features a segmented design, which includes multiple sections that are electrically isolated from each other. This segmentation allows for the electrode pads to be incorporated into the distal tip 126 and to be isolated from one another. A first pair of electrode pads 510A- 1 and 510A-2 are separated by an insulative portion 530. A second pair of electrode pads 510B-1 and 510B-2 are also separated from one another by an insulative portion 530. The segmented distal tip ensures that the electrodes are properly positioned and aligned, facilitating accurate bioimpedance measurements. The electrodes 510A-1 and 51 OA-2 may have a shape that wraps around a majority of the circumference of the distal tip 126. The electrodes 510B-1 and 510B-2 may have a shape that wraps around a majority of the circumference of the inlet tube 120.

[0243] The segmented design of the distal tip 126 and / or inlet tube 120 allows for the integration of multiple electrode pads 310 and conductive portions 330 without compromising the flexibility or structural integrity of the guide cannula 101. This configuration enables the system to provide detailed data on the volume of blood in the heart or a chamber of the heart, which is important for assessing cardiac function and adjusting the operation of the cardiac assist system in real-time.

[0244] The design of the electrode pads 510A-1, 510A-2, 510B-1, and 51 OB-2, and insulative portions 530 ensures that they can withstand the mechanical stresses encountered during insertion and operation within the cardiovascular environment. The electrode pads 510A-1, 510A-2, 510B-1, and 510B-2, and insulative portions 530 can be integral to the distal tip 126 and / or the inlet tube 120. In some examples, rigid side-plated PCBs can be inserted into the distal tip 126. In some examples, the inlet tube 120 can be coated with an electrically insulating material and the coating can be masked or removed to expose portions of the conductive inlet tube 120 material. The electrode pads 510A-1, 510A-2, 510B-1, and 510B-2, are connected to the electrical traces within the electrical conducting element, allowing for the transmission of bioimpedance signals to the controller for analysis.Radi opaque Markers

[0245] It can be difficult to visualize whether a cardiac assist system is properly placed across the aortic valve to pull blood from the left ventricle and deposit it in the aorta. To function properly and safely, the cardiac assist device should be positioned such that the aortic valve is aligned within a specific valve alignment range of the length of the cardiac assist system. Radiopaque markers placed on the cardiac assist system can create clear identifying marks which may further improve ease of use and safety of cardiac assist systems.

[0246] FIG. 30 shows a cardiac assist system positioned within a patient's heart 60. The insertion of a cardiac assist system into a patient's heart involves a series of precise and controlled steps to ensure proper placement and functionality. The process begins with the preparation of the guide cannula, which serves as the main conduit for blood flow within the cardiac assist system.

[0247] To insert the cardiac assist system, a clinician first gains vascular access, such as through the femoral artery. A guidewire is then advanced through the vascular system towards the heart, navigating through the aorta and into the left ventricle. The guide cannula, equipped with a guidewire port, is threaded over the guidewire, allowing the clinician to guide the cannula into the correct position within the heart. The distal end of the guide cannula, featuring a plurality of inlet openings, is positioned within the left ventricle, while the proximal end, containing the motor housing, remains in the aorta.

[0248] The aortic valve 66 is located between the left ventricle 67 and the aorta 65 of the heart 60. The cardiac assist system comprises a guide cannula with a motor housing 115 and a distal tip 126. The guide cannula is designed to facilitate blood flow from the left ventricle 67 to the aorta 65. The motor housing 115 drives an impeller that moves blood through the guide cannula, from the distal tip 126 in the left ventricle 67, through the aortic valve 66, and into the aorta 65. The motor housing 115 is positioned within the aorta 65, while the distal tip 126 is located within the left ventricle 67. The guide cannula traverses the aortic valve 66, ensuring proper alignment and functionality of the cardiac assist system. The landing zone 300 is a specific region along the length of the guide cannula that ideally aligns with the aortic valve 66 during operation of the cardiac assist system, in particular a cardiac assist system having a guidewire port 134 positioned on the guide cannula distal to the landing zone 300. This landing zone 300 can ensure that the blood flow is correctly directed from the leftventricle to the aorta. The placement of the cardiac assist system within the heart 60 is designed to improve blood flow and support the heart's function.

[0249] FIG. 31 shows a radiographic image illustrating the placement of the guide cannula within a patient's heart without radiopaque markers installed on the guide cannula, highlighting components and their alignment.

[0250] The motor housing 115 is positioned at the proximal region 121 of the guide cannula. The motor housing 115 contains the motor that drives the impeller, facilitating blood flow through the guide cannula. The motor housing 115 is visible in the radiographic image. The distal region 123 of the guide cannula is shown extending into the left ventricle of the heart. The distal tip 126 is also radiopaque, allowing for clear visualization in the radiographic image. As illustrated in FIG. 31, without radiopaque markers installed on the guide cannula, the motor housing 115 and distal tip 126 may be the only visible features of the guide cannula. Therefore, where a landing zone 300 is not delineated with radiopaque markers, it can be difficult to accurately locate the guide cannula within a patient’s heart.

[0251] The landing zone 300 is a specific region along the length of the guide cannula that is intended to align with the aortic valve during operation. The landing zone 300 is a specific region between the motor housing 115 and the distal tip 126. The landing zone 300 can begin at the distal end of any opening in the inlet tube 120 where blood is expelled, for example the outlet openings 128. The landing zone 300 can end at the proximal end of the next opening moving distally from the beginning of the landing zone 300 that allows blood to enter the inlet tube 120, such as inlet openings or a guidewire port. The landing zone 300 is marked by radiopaque markers, which are integrated into the electrical conducting element of the guide cannula. These markers enhance the visibility of the landing zone 300, enabling clinicians to visually confirm the correct placement of the guide cannula within the heart. The radiopaque markers ensure that the guide cannula is properly aligned with the aortic valve, optimizing blood flow from the left ventricle to the aorta.

[0252] FIG. 32 shows a detailed view of a guide cannula 101, illustrating the implementation of radiopaque markers on the inlet tube 120. The electrical conducting element 180 is helically wound around the inlet tube 120. The electrical conducting element 180 comprises multiple layers and is configured to contact at least one sensor within the cardiac assist system. The electrical conducting element 180 may play a role in the bioimpedancemeasurement, enabling the monitoring and adjustment of the cardiac assist system's performance or monitoring of the patient’s condition, such as cardiac output, contractility, pulsatility or other metric.

[0253] The landing zone 300 is a specific region along the length of the guide cannula 101 that aligns with the aortic valve during proper operation. The landing zone 300 may be marked by radiopaque markers 301 and 302, which in some embodiments can be integrated into the electrical conducting element 180 of the guide cannula 101 or may be separate radiopaque elements. The radiopaque markers 301 and 302 delineate the distal end of the landing zone 300 and the proximal end of the landing zone 300, respectively. These markers enhance the visibility of the landing zone 300, enabling clinicians to visually confirm the correct placement of the guide cannula 101 within the heart. The radiopaque markers ensure that the guide cannula 101 is properly aligned with the aortic valve, optimizing blood flow from the left ventricle to the aorta.

[0254] The first radiopaque marker 301 is positioned at the distal region 123 of the landing zone 300. The first radiopaque marker 301 may be integrated into the electrical conducting element 180 and is designed to enhance visibility under medical imaging techniques such as fluoroscopy. The first radiopaque marker 301 can be positioned at least partially circumferentially around the inlet tube 120. In some examples, the first radiopaque marker 301 does not overlap with the electrical conducting element 180. The width of the first radiopaque marker 301 may be less than or equal to the circumference of the inlet tube 120 such that the marker can wrap around the inlet tube 120 without overlapping itself. In some examples, if the radiopaque marker 301 includes a conductive material, the radiopaque marker 301 can be insulated from the conductive layers of the electrical conducting element 180.

[0255] The second radiopaque marker 302 is positioned at the proximal region 121 of the landing zone 300. The second radiopaque marker 302 may be integrated into the electrical conducting element 180 and is designed to enhance visibility under medical imaging techniques such as fluoroscopy. The second radiopaque marker 302 can be positioned at least partially circumferentially around the inlet tube 120. In some examples, second radiopaque marker 302 does not overlap with the electrical conducting element 180. The width of the second radiopaque marker 302 may be less than or equal to the circumference of the inlet tube 120 such that the marker can wrap around the inlet tube 120 without overlapping itself. In someexamples, if the radiopaque marker 302 includes a conductive material, the radiopaque marker 302 can be insulated from the conductive layers of the electrical conducting element 180.

[0256] The implementation of the radiopaque markers 301, 302 on the inlet tube 120 of the guide cannula 101 enhances the visibility of the landing zone 300 under medical imaging techniques, facilitating the correct placement and alignment of the guide cannula 101 within the heart. This configuration improves the performance of the cardiac assist system, providing effective support to the cardiovascular system while reducing the risk of complications during and after the insertion process.

[0257] FIG. 33 shows an example configuration of electrical conducting element 180 with integrated radiopaque markers in a manufacturing configuration prior to being wrapped around a guide cannula 101 or other device. The electrical conducting element 180 includes multiple components and features that facilitate the integration and functionality of the electrical conducting element 180, as described elsewhere herein. In the example electrical conducting element of FIG. 33, the electrical conducting element 180 can comprise multiple layers, including a substrate layer, electrical traces, and a dielectric layer. Throughout the description of FIG. 33, reference will also be made to components illustrated in FIGS. 21-22F. Other configurations of an electrical conducting element 180, such as those having more or fewer components than those described with reference to FIG. 33, can equally be implemented in conjunction with the disclosed cardiac assist systems.

[0258] The electrical conducting element 180 is designed to provide electrical connectivity within a cardiac assist system, facilitating the monitoring and adjustment of the system's performance. The electrical conducting element 180 is configured to be helically wound around a sheath of a guide cannula, ensuring proper alignment and secure attachment.

[0259] The electrical conducting element 180 includes a first radiopaque marker 301 and a second radiopaque marker 302. The radiopaque markers advantageously enhance visibility under medical imaging techniques such as fluoroscopy. These radiopaque markers are integrated into the electrical conducting element 180 which advantageously makes the radiopaque markers easy to assemble on a guide cannula. The first radiopaque marker 301 is positioned at the distal region 123 of the electrical conducting element 180, while the second radiopaque marker 302 is positioned at the proximal region 121. The radiopaque markers 301and 302 are designed to delineate a landing zone of the cardiac assist system, ensuring proper placement and alignment within the heart.

[0260] The first radiopaque marker 301 and the second radiopaque marker 302 each have a width 304 such that when placed circumferentially around the inlet tube 120, the markers do not overlap with the electrical conducting element 180. The length 305 of the radiopaque markers 301 and 302 is less than or equal to the length of a section of the inlet tube 120 that is not configured to bend, ensuring that bending does not put stress on the electrical conducting element 180.

[0261] The radiopaque markers 301 and 302 are oriented at an angle 303 that is perpendicular to a longitudinal axis 140 of the cardiac assist system. This orientation ensures that the radiopaque markers 301 and 302 wrap circumferentially around the inlet tube 120, providing clear and distinct visual markers under medical imaging techniques. The radiopaque markers 301 and 302 are made from a radiopaque substance such as titanium, copper, strontium, ytterbium, silver, gold, bromine, barium, or strontium, ensuring high visibility under fluoroscopy.

[0262] The integration of the radiopaque markers 301 and 302 into the electrical conducting element 180 enhances the visibility of the landing zone 300 under medical imaging techniques, ensuring the correct placement and alignment of the guide cannula within the heart. This configuration improves the performance of the cardiac assist system, providing effective support to the cardiovascular system while reducing the risk of complications during and after the insertion process. Furthermore, it improves manufacturability by incorporating components and reducing steps of applying the components.

[0263] 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.

[0264] 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 thenovel 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.

[0265] 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.

[0266] 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.

[0267] 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 introductory phrases “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.

[0268] 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.”

Claims

WHAT IS CLAIMED IS:

1. A mechanical circulatory support system, comprising: an impeller; an impeller cage at least partially surrounding the impeller; and an inlet tube, wherein a proximal end of the inlet tube is radially outward of a distal end of the impeller cage, and wherein the proximal end of the inlet tube continuously applies a radially inward compressive force on the distal end of the impeller cage.

2. The system of claim 1, wherein the inlet tube comprises a shape memory alloy.

3. The system of claim 1, wherein the inlet tube comprises Nitinol.

4. The system of claim 1, wherein the impeller cage comprises titanium.

5. The system of claim 1, wherein the impeller cage comprises a material that is more rigid than the inlet tube.

6. The system of claim 1, wherein the proximal end of the inlet tube comprises a plurality of first alignment features and the distal end of the impeller cage comprises a plurality of second alignment features, and wherein the plurality of first alignment features are aligned with the plurality of second alignment features.

7. The system of claim 1, wherein the impeller cage comprises a shoulder proximal to the distal end of the impeller cage, the shoulder having a larger diameter than the distal end of the impeller cage, and wherein the proximal end of the inlet tube is radially aligned with the shoulder of the impeller cage.

8. The system of claim 1, wherein the impeller cage comprises a bearing configured to retain structure of the impeller cage.

9. The system of claim 8, wherein the bearing continuously applies a radially outward force on the proximal end of the inlet tube.

10. The system of claim 8, wherein the bearing is a star bearing.

11. The system of claim 1, further comprising a motor configured to drive the impeller.

12. The system of claim 11, wherein the impeller is magnetically coupled to the motor.

13. The system of claim 11, wherein the motor is encapsulated such that it is not connected to the impeller by a shaft.

14. The system of claim 11 , wherein the impeller is held between bearings.

15. The system of claim 11, wherein the motor is encapsulated in a motor housing.

16. The system of claim 1, wherein the inlet tube comprises a base tube having a flexible section and a coil-reinforced tube disposed over the flexible section of the base tube.

17. The system of claim 16, wherein the coil-reinforced tube comprises a metal coil encapsulated in a polymer.

18. The system of claim 16, wherein the flexible section comprises a helical flexible region between helical windings of a helical mounting surface.

19. The system of claim 16, wherein an electrical conducting element is between an outer surface of the base tube and an inner surface of the coil-reinforced tube.

20. A mechanical circulatory support system, comprising: an impeller; an impeller cage at least partially surrounding the impeller, the impeller cage comprising a plurality of first alignment features; and an inlet tube comprising a plurality of second alignment features, wherein a proximal end of the inlet tube is press fit with a distal end of the impeller cage such that the plurality of first alignment features of the impeller cage are aligned with the plurality of second alignment features of the inlet tube.

21. The system of claim 20, wherein at least one of the plurality of first alignment features and the plurality of second alignment features are a plurality of holes.

22. The system of claim 20, wherein a diameter of the proximal end of the inlet tube is greater than a diameter of the distal end of the impeller cage.

23. The system of claim 20, wherein the inlet tube comprises a shape memory alloy.

24. The system of claim 20, wherein the inlet tube comprises Nitinol.

25. The system of claim 20, wherein the impeller cage comprises titanium.

26. The system of claim 20, wherein the proximal end of the inlet tube continuously applies a radially inward compressive force on the distal end of the impeller cage.

27. The system of claim 20, wherein the impeller cage comprises a shoulder proximal to the distal end of the impeller cage, the shoulder having a larger diameter than the distal end of the impeller cage, and wherein the proximal end of the inlet tube is radially aligned with the shoulder of the impeller cage.

28. The system of claim 20, wherein at least a portion of the inlet tube distal to the impeller cage has an inner diameter smaller than an outer diameter of a mating section of the impeller cage.

29. A method for constructing a mechanical circulatory support device, the method comprising: inserting an inlet tube into an inlet tube holder, the inlet tube comprising a first plurality of holes and a second plurality of holes, wherein the first plurality of holes are distal to the second plurality of holes; inserting an impeller cage into an impeller cage holder; engaging a plurality of pins of the inlet tube holder in the first plurality of holes of the inlet tube; advancing the inlet tube holder toward the impeller cage holder to advance the inlet tube over the impeller cage, such that a proximal end of the inlet tube and the second plurality of holes are radially outward of a distal end of the impeller cage; retracting the plurality of pins from the first plurality of holes; engaging the plurality of pins in the second plurality of holes; and further advancing the inlet tube holder toward the impeller cage holder to advance the inlet tube over the impeller cage.

30. The method of claim 29, further comprising ceasing advancing the inlet tube holder when the second plurality of holes align with a plurality of alignment features of the impeller cage.

31. The method of claim 29, further comprising retracting the plurality of pins from the second plurality of holes.

32. The method of claim 29, wherein the inlet tube is configured to expand as it advances over the impeller cage.

33. The method of claim 32, wherein the inlet tube is configured to expand as it advances over a tapered portion of the impeller cage.

34. The method of claim 29, further comprising removing the inlet tube from the inlet tube holder and removing the impeller cage from the impeller cage holder.

35. The method of claim 29, further comprising cooling the inlet tube before advancing the inlet tube holder toward the impeller cage holder.

36. The method of claim 29, further comprising warming the inlet tube after the inlet tube is advanced over the impeller cage.

37. The method of claim 29, further comprising ceasing advancing the inlet tube holder when the proximal end of the inlet tube abuts a shoulder of the impeller cage, the shoulder having a larger diameter than the distal end of the impeller cage.

38. The method of claim 29, wherein an inner diameter of the inlet tube is smaller than an outer diameter of a mating portion of the impeller cage.

39. A method for constructing a mechanical circulatory support device, the method comprising: inserting an inlet tube into an inlet tube holder, the inlet tube comprising a plurality of holes; inserting an impeller cage into an impeller cage holder; engaging a plurality of pins of the inlet tube holder in the plurality of holes of the inlet tube; and advancing the inlet tube holder toward the impeller cage holder to advance the inlet tube over the impeller cage, such that a proximal end of the inlet tube is radially outward of a distal end of the impeller cage.

40. The method of claim 39, further comprising retracting the plurality of pins from the plurality of holes.

41. The method of claim 39, wherein the inlet tube is configured to expand as it advances over the impeller cage.

42. The method of claim 41, wherein the inlet tube is configured to expand as it advances over a tapered portion of the impeller cage.

43. The method of claim 39, further comprising removing the inlet tube from the inlet tube holder and removing the impeller cage from the impeller cage holder.

44. The method of claim 39, further comprising cooling the inlet tube before advancing the inlet tube holder toward the impeller cage holder.

45. The method of claim 39, further comprising warming the inlet tube after the inlet tube is advanced over the impeller cage.

46. The method of claim 39, further comprising ceasing advancing the inlet tube holder when the proximal end of the inlet tube abuts a shoulder of the impeller cage, the shoulder having a larger diameter than the distal end of the impeller cage.

47. The method of claim 39, wherein an inner diameter of the inlet tube is smaller than an outer diameter of a mating portion of the impeller cage.

48. A system for constructing a mechanical circulatory support device, comprising: an inlet tube holder configured to hold an inlet tube, the inlet tube holder comprising: a plurality of pins, the plurality of pins configured to engage a plurality of holes of the inlet tube; and a pin actuator configured to transition the plurality of pins between an engaging position and a retracted position; and an impeller cage holder configured to hold an impeller cage.

49. The system of claim 48, wherein the inlet tube holder is restricted to translational movement toward and away from the impeller cage holder.

50. The system of claim 48, wherein the impeller cage holder is restricted to translational movement toward and away from the inlet tube holder.

51. The system of claim 48, wherein the inlet tube holder comprises a rotational orientation locking component configured to prevent the inlet tube from rotating about a central axis.

52. The system of claim 48, wherein the impeller cage holder comprises a rotational orientation locking component configured to prevent the impeller cage from rotating about a central axis.

53. A cardiac assist system comprising: a guide cannula comprising an inlet tube having one or more helical slots and an inlet opening for receiving blood, the guide cannula arranged between a sensor head unit and an end unit comprising a proximal sensor and a motor; an outlet opening for discharging the blood; and an electrical conducting element coupled to the inlet tube of the guide cannula proximate the one or more helical slots, the electrical conducting element comprising a plurality of layers and a sensor contact region configured to contact at least one sensor, wherein the electrical conducting element contacts the proximal sensor.

54. The cardiac assist system of claim 53, wherein the one or more helical slots comprise a plurality of helical slots and wherein at least a portion of the electrical conducting element is disposed between two adjacent helical slots.

55. The cardiac assist system of claim 53, wherein the electrical conducting element passes around the motor.

56. The cardiac assist system of claim 53, wherein the end unit further comprises a void proximal from the motor.

57. The cardiac assist system of claim 53, wherein the electrical conducting element comprises a flexible printed circuit board.

58. The cardiac assist system of claim 53, further comprising one or more sensors in electrical contact with the electrical conducting element.

59. The cardiac assist system of claim 53, wherein the electrical conducting element is connected to one or more distal sensors disposed in a distal tip of the guide cannula.

60. The cardiac assist system of claim 53, wherein the electrical conducting element is connected to one or more proximal sensors disposed in a proximal cap of the guide cannula.

61. A conduit for a cardiac assist system, the conduit comprising: a guide cannula comprising a sheath; and an electrical conducting element helically wound around the sheath of the guide cannula, wherein the electrical conducting element comprises a plurality of alignment indicators.

62. The conduit of claim 61, wherein the plurality of alignment indicators are configured to align circumferentially with one another.

63. The conduit of claim 61, wherein the plurality of alignment indicators comprise tabs or notches.

64. The conduit of claim 61, wherein the electrical conducting element further comprises bend portions configured to adjust an alignment of the electrical conducting element.

65. The conduit of claim 61, wherein the sheath further comprises one or more helical slots.

66. The conduit of claim 65, wherein the sheath further comprises one or more guide indicators.

67. The conduit of claim 66, wherein the one or more guide indicators comprise spaces between the one or more helical slots.

68. The conduit of claim 66, wherein the one or more guide indicators comprise laser etchings on the sheath.

69. A conduit for a cardiac assist system, the conduit comprising: a guide cannula comprising an inlet tube; and one or more radiopaque markers disposed on the inlet tube; wherein the one or more radiopaque markers comprises: a first radiopaque marker disposed at a distal end of a landing zone; and a second radiopaque marker disposed at a proximal end of the landing zone.

70. The conduit of claim 69, wherein the landing zone is a region along a length of the guide cannula configured to align with an aortic valve of a patient during operation of the cardiac assist system.

71. The conduit of claim 69, wherein the one or more radiopaque markers are integral to an electrical conducting element.

72. The conduit of claim 71, further comprising one or more helical slots disposed on the inlet tube and an inlet opening for receiving blood.

73. The conduit of claim 72, wherein the electrical conducting element comprises a flexible printed circuit board, the electrical conducting element configured to electrically connect components along a length of the inlet tube.

74. The conduit of claim 69, wherein the one or more radiopaque markers wrap around a circumference of the inlet tube.

75. The conduit of claim 69, wherein the one or more radiopaque markers wrap around at least a half of a circumference of the inlet tube.

76. A conduit for a cardiac assist system, the conduit comprising: a guide cannula comprising an inlet tube; an electrical conducting element helically wound around the inlet tube of the guide cannula, the electrical conducting element comprising one or more electrode pads; and one or more electrodes arranged on the one or more electrode pads.

77. The conduit of claim 76, wherein the electrical conducting element comprises a four- wire micro ribbon cable.

78. The conduit of claim 76, wherein the one or more electrodes are soldered to the electrical conducting element.

79. The conduit of claim 76, wherein the one or more electrodes comprise conductive portions of the guide cannula, wherein the conductive portions are separated by one or more insulative regions.

80. The conduit of claim 76, wherein the one or more electrodes are clamped to the electrical conducting element, and wherein the one or more electrodes are configured to communicate signals to a controller configured to measure bioimpedance.

81. The conduit of claim 76, wherein the one or more electrodes comprises a first pair of electrodes positioned in a distal region of the electrical conducting element.

82. The conduit of claim 76, wherein the one or more electrodes comprises a first pair of electrodes positioned in a proximal region of the electrical conducting element.

83. The conduit of claim 82, wherein the one or more electrodes further comprises a second pair of electrodes positioned in a distal region of the electrical conducting element.

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