Systems and methods for pump-assisted blood circulation

Abstract

To provide systems, devices, and methods that employ a pump to assist or support blood flow.SOLUTION: An apparatus for pumping blood may include a pump housing having an outer wall disposed about a longitudinal pump axis, and having an upstream end and a downstream end; a blood flow straightener having a plurality of fins and positioned in the upstream end of the pump housing and secured to the pump housing by the plurality of fins; a diffuser having a plurality of diffuser fins and positioned in the downstream end of the pump housing and secured to the pump housing by the plurality of diffuser fins; and an impeller positioned between the blood flow straightener and the diffuser, and including a plurality of impeller blades. The apparatus may further include a pump drive configured to impart a rotational motion to the impeller by applying a magnetic field.SELECTED DRAWING: Figure 14

Description

[Technical field]

[0001] [CROSS REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of priority to U.S. Provisional Application No. 63 / 080,509, filed September 18, 2020, the entire disclosure of which is incorporated herein by reference.

[0002] Various aspects of the present disclosure relate generally to systems and methods using pumps to assist blood circulation. In one embodiment, the present disclosure relates to systems, devices, and associated methods for the use and control of axial flow pumps to provide circulatory assistance or bypass. In embodiments, the pump can be a multi-stage axial flow pump used to circulate blood in intraventricular or extracorporeal applications. [Background technology]

[0003] In patients with cardiac disease, the heart may have difficulty circulating blood throughout the patient's body. For example, patients with heart failure may have a deficiency in ventricular blood pumping due to problems with the strength or rhythm of one or more ventricles' contractions. In other situations, such as in surgical or emergency settings, it may be necessary to bypass some or all of the blood flow. In such cases, pumps may be implanted into the heart and vascular system or otherwise connected to the patient's circulatory system to assist or bypass the heart and improve blood flow. Because these pumps are critical to the health and survival of the patient, they must be effective, efficient, and reliable. The present disclosure relates to methods and systems focused on addressing one or more of the above problems or other problems in the art. Summary of the Invention [Problem to be solved by the invention]

[0004] Aspects of the present disclosure relate, inter alia, to systems, devices, and methods that use pumps to assist or support blood flow. In embodiments, the axial flow pump assists ventricular circulation or provides a partial or complete bypass for blood circulation. Each aspect disclosed herein can include one or more of the features described in association with any of the other disclosed aspects. [Means for solving the problem]

[0005] For example, an apparatus for pumping blood may include a pump housing having an outer wall radially disposed about a longitudinal pump axis and having an upstream end and a downstream end; a flow straightener having a number of fins and positioned at the upstream end of the pump housing and secured to the pump housing by the number of fins; a diffuser having a number of diffuser fins and positioned at the downstream end of the pump housing and secured to the pump housing by the number of diffuser fins; and an impeller positioned within the pump housing between the flow straightener and the diffuser and including a number of impeller blades. The apparatus may further include a pump drive positioned circumferentially around the impeller and configured to impart rotational motion to the impeller by applying a magnetic field to the impeller, the impeller being supported by an upstream bearing cooperating with an upstream bearing mount of the flow straightener and a downstream bearing cooperating with a downstream bearing mount of the diffuser.

[0006] In accordance with the present disclosure, an apparatus for pumping blood includes a pump housing having an outer wall radially disposed about a longitudinal pump axis and having an upstream end and a downstream end; a blood flow straightener having a plurality of fins and positioned at the upstream end of the pump housing; a diffuser having a plurality of diffuser fins and positioned at the downstream end of the pump housing; an impeller positioned within the pump housing between the blood flow straightener and the diffuser and including a plurality of impeller blades; and a stator cartridge including a stator housing and a stator core, the stator cartridge being removably positioned circumferentially around the pump housing and configured to impart rotational motion to the impeller by applying a magnetic field to the impeller.

[0007] The disclosed device for pumping blood may include a pump housing having an outer wall radially disposed about a longitudinal pump axis, the pump housing having upstream and downstream ends, male threads between the upstream and downstream ends, and a flange extending radially outward from the outer wall; a flow straightener having a number of fins and positioned at the upstream end of the pump housing; and a diffuser having a number of diffuser fins and positioned at the downstream end of the pump housing. The disclosed device may further include an impeller positioned within the pump housing between the flow straightener and the diffuser and including a number of impeller blades; a pump drive positioned circumferentially around the outer wall and configured to impart rotational motion to the impeller; and a tube expander configured to thread onto the male threads and abut the flange to modify a dimension of the pump housing.

[0008] It should be understood that both the description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure as claimed.

[0009] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate exemplary aspects of the disclosure and, together with the description, serve to explain the principles of the disclosure. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a side view of a pump assembly having a housing illustrated as being transparent, according to an aspect of the present disclosure. [Diagram 2] FIG. 2 is a side view of internal components of a pump assembly according to an aspect of the present disclosure. [Figure 3A] FIG. 13 is a perspective view of a flow straightener and a front bearing in a separated state according to an aspect of the present disclosure. [Figure 3B] FIG. 13 is a perspective view of an installed flow straightener and front bearing according to an aspect of the present disclosure. [Figure 4A] FIG. 2 is a front perspective view of an impeller according to an aspect of the present disclosure. [Figure 4B] FIG. 2 is a rear perspective view of an impeller according to an aspect of the present disclosure. [Figure 5A] FIG. 13 is a perspective view of a diffuser and a rear bearing in a separated state according to an aspect of the present disclosure. [Figure 5B] FIG. 13 is a perspective view of an installed diffuser and rear bearing according to an aspect of the present disclosure. [Figure 6] FIG. 1 illustrates a pump assembly configured for intraventricular use, according to aspects of the present disclosure. [Figure 7] FIG. 1 is a front view of an installed intraventricular pump assembly, according to aspects of the present disclosure. [Figure 8] FIG. 1 is a perspective partial cross-sectional view of a pump assembly configured for intraventricular application, according to an aspect of the present disclosure. [Figure 9] FIG. 9 is an exploded perspective view of the pump assembly of FIG. 8 according to an embodiment of the present disclosure. [Figure 10] FIG. 9 is an exploded perspective view of the pump housing of FIG. 8 according to an embodiment of the present disclosure. [Figure 11] FIG. 9 is an exploded perspective view of the flow tube of FIG. 8 according to an embodiment of the present disclosure. [Figure 12] FIG. 1 illustrates a pump assembly configured for extracorporeal use, according to an aspect of the present disclosure. [Figure 13] FIG. 13 illustrates a pump assembly configured for an alternative extracorporeal application, according to aspects of the present disclosure. [Figure 14]FIG. 1 is an exploded cross-sectional view of a pump assembly configured for extracorporeal use, according to an aspect of the present disclosure. [Figure 15A] FIG. 2 is a perspective view of a stator cartridge in an open state according to aspects of the present disclosure. [Figure 15B] FIG. 1 is a perspective view of a stator cartridge in a closed state according to an aspect of the present disclosure. [Figure 16] FIG. 13 is a side view of a pump assembly with a tube dilator installed, according to an aspect of the present disclosure. [Figure 17] FIG. 17 is a cross-sectional view of a pump assembly with the tube expander of FIG. 16 installed, according to an embodiment of the present disclosure. [Figure 18] FIG. 2 is a plot of head pressure ("H") generated by a pump as a function of flow rate ("Q") through the pump, according to one embodiment of the present disclosure. [Figure 19] FIG. 1 is a schematic diagram of a multi-stage pump assembly according to an aspect of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Aspects of the present disclosure relate to stems and methods of using a multi-stage axial pump to circulate blood in intraventricular or extracorporeal applications. An axial pump according to the present disclosure may be implanted, at least in part, in a cardiac ventricle, such as the right ventricle. In such intraventricular applications, the pump may be a component of a cardiac assist system that assists the heart in circulating blood.

[0012] Additionally, an axial pump according to the present disclosure can be connected to a patient's circulatory system such that the pump remains external to the patient's body. In these extracorporeal applications, the pump can be a component of a partial or total bypass system that circulates blood from one point in the circulatory system to another point in the circulatory system.

[0013] Additionally, the axial pump may be connected to the patient's circulatory system and implanted, and connected to the circulatory system using an implantable connector and vascular graft in a manner similar to a ventricular device.

[0014] For ease of description, portions of the disclosed device and / or its components are referred to as upstream and downstream portions. It is noted that the term "upstream" is intended to refer to portions closer to the source of blood flow, and the term "downstream" is used herein to refer to portions further away from the source of blood flow. Furthermore, as used herein, the terms "about," "approximately," and "substantially" indicate a range of values ​​within ±10% of the stated or suggested value. Additionally, terms indicating the geometry of components / surfaces refer to exact and approximate shapes.

[0015] 1, a pump assembly 100 is shown in accordance with one or more embodiments of the present disclosure. The pump assembly 100 may include a pump housing 110 (shown partially transparent in FIG. 1) for housing blood contacting components of the pump assembly 100, through which blood may be pumped. The pump housing 110 may include a flow tube 111 having a threaded portion 112 and a flanged portion 113 on an exterior surface thereof.

[0016] The pump housing 110, and in particular the flow tube 111, has an opening at an upstream end 114 and another opening at a downstream end 115, with the flow tube 111 fluidly connecting the upstream end 114 with the downstream end 115. The flow tube 111 can have a substantially constant inner diameter of about 0.5 inches (about 12.5 mm) and can have a generally constant outer diameter in areas other than the areas of the threads 112 and the flanges 113. The threads 112 can be male threads on the pump housing 110 configured to engage with a tube expander 116 (described further below), and the flanges 113 can project radially from the flow tube 111 against which the tube expander 116 abuts. In some embodiments, the threads 112 can be upstream of the flanges 113 and can be located in an area adjacent and radially outward of the flow straightener 120. The purpose and function of the tube expander 116 is described below with respect to FIGS. 16 and 17.

[0017] The blood contacting components of the pump assembly 100, such as the flow straightener 120, the impeller 130, and the diffuser 140, may be secured and housed within the flow tube 111. These internal components are shown in FIG. 2 with the pump housing 110 removed.

[0018] In some embodiments, as blood flows from the upstream end 114 of the pump housing 110 to the downstream end 115 of the pump housing 110, the blood may also pass through a flow straightener 120, which may act as a support for bearing components that allow rotation of the impeller 130. The flow straightener 120 may be located within the pump housing 110 and secured thereto by, for example, an interference fit, a welded connection integrally formed with the pump housing 110, and / or other suitable methods. The flow straightener 120 may include, for example, three fins 122, each of which may have a teardrop-shaped cross-section with a narrow pointed end downstream of a leading edge / rounded end. The fins 122 may project radially outward from a central hub 123 and may be equally spaced around the circumference of the central hub 123. For example, in an embodiment having three fins, the fins may be spaced apart at 120°.

[0019] The leading edges of the fins may extend radially from the central hub 123 and substantially perpendicular to the central longitudinal axis of the flow straightener. Each fin may have an axial width of about 0.15 to 0.25 inches (about 4 to 7 mm). Such small widths are particularly suitable for applications in which at least a portion of the pump is located within the right ventricle so that the pump does not protrude too far into the ventricle. Each fin may have a radial length selected to extend from the central hub to the inner wall of the flow tube 111. Providing the flow straightener 120 with an outer diameter substantially equal to the inner diameter of the flow tube allows the flow straightener to be press fit into place and prevents flow between the ends of the fins 122 and the pump housing 110.

[0020] 3A and 3B, the flow straightener 120 can have a bearing mount 124 inserted into a downstream opening in the central hub. The bearing mount 124 can include a bearing surface that cooperates with a bearing in the impeller. The forward bearing mount 124 can support the rotating impeller 130 on a bearing 134 located at the upstream end of the impeller 130 and rotating with the impeller 130, while still allowing smooth flow through the pump housing 110.

[0021] The above-mentioned leading edge design, fin dimensions, and distance between the downstream edge of the fins 122 and the leading edge of the blades of the impeller 130 may be particularly advantageous for limiting incoming flow turbulence and reducing blood stagnation within the pump. Although the flow straightener 120 is illustrated and described with three symmetrically arranged, identically shaped and sized fins 122, embodiments of the present disclosure include flow straighteners 120 having more or less than three fins 122, fins 122 asymmetrically arranged about the hub 123, and fins 122 of various shapes and sizes. In some embodiments, the axial length of the flow straightener 120 and fins 122 may be reduced to a length appropriate for the desired specifications of the bearing mount 124.

[0022] After passing through the flow straightener 120, the blood flow then impinges on the impeller 130. The impeller 130 can be driven to move blood through the flow tube, and to aid in the durability and reliability of the pump assembly 100, the impeller 130 (including the blades 132 and bearings 134) can be the only moving part within the pump housing 110. FIGS. 4A and 4B show front and rear perspective views, respectively, of an impeller according to an embodiment of the present disclosure. The impeller 130 can include a number of impeller blades 132, e.g., six blades, protruding from a central portion of the impeller 130. The impeller 130 can have bearings 134 inserted into and extending from centrally located openings on the upstream and downstream sides. The bearings 134 can rotate within the upstream bearing mount 124 and downstream bearing mount 144 to reduce friction while allowing smooth blood flow through the pump housing 110.

[0023] In some embodiments, some impeller blades 132a may helically wrap around a central portion of the impeller 130 along a substantial portion of the length of the impeller 130, while other arcuate blades 132b may be arcuately formed around a central portion of the impeller 130 along a portion of the impeller 130's length that is less than a substantial portion of the length that the helical blades 132 extend. In some embodiments, the helical blades 132a have a pitch that varies along the axial length of the impeller 130 such that the pitch of the helical blades 132a at an upstream portion of the impeller 130 is less than the pitch at a downstream portion of the impeller 130. The arcuate blades 132b may be interspersed among (e.g., circumferentially alternating with) the spirally wound blades 132a and have an initial arcuate shape that begins (with a leading edge) at a central portion of the impeller 130 and flattens (becomes essentially straight) as the arcuate blades 132b approach the downstream end of the impeller 130. Each impeller blade 132, including both the spirally wound blades 132a and the arcuate blades 132b, may extend substantially parallel to one another and be equally spaced around the impeller 130 at the downstream end of the impeller 130.

[0024] The impeller 130 can rotate at about 5,000 to about 15,000 rpm and generate a blood flow of about 1 to 6 L / min, depending on variables such as the flow resistance of the bypass circuit tubing. The particular geometry of the impeller 130 and impeller blades 132 can affect the flow conditions and efficiency of the pump assembly 100. For example, as the blood flow approaches the impeller 130, the shape and angle of the leading edges of the impeller blades 132 can cause areas of flow separation and / or flow reversal. Flow separation and flow reversal are conditions that can damage blood cells in the blood stream and / or cause the accumulation of blood clots within the pump assembly 100. In some applications, flattening and / or rounding the leading edges of the impeller blades 132 can help prevent these conditions.

[0025] Additionally, in some embodiments, the axial length and angle of the impeller blades can be adjusted to improve flow characteristics for various circulating pressure and flow applications. For example, providing a longer impeller 130 can improve flow conditions where high flow rates at high pressure are indicated, while an impeller 130 with blades 132 positioned at a steeper angle can improve flow conditions for applications requiring low flow rates at high pressure. In some embodiments, flow and pressure requirements can be met using multiple stages of impeller / diffuser pairs, as described below with respect to FIG. 19.

[0026] As the blood passes through the impeller 130 , the blood flow approaches a diffuser 140 located at the downstream end of the impeller 130 to improve the flow characteristics before exiting the pump housing 110 .

[0027] In some embodiments, the straightener 120 and diffuser 140 may be stationary components that may serve as the upstream bearing mount 124 and downstream bearing mount 144; reducing the number of moving parts may aid in reliability, manufacturability, and system efficiency. In such embodiments, the impeller 130 (including the blades 132 and bearings 134) may be the only moving pump component.

[0028] As shown in FIGS. 5A and 5B, the diffuser 140 can have a bearing mount 144 inserted into the upstream opening of the diffuser 140. The bearing mount 144 can include a bearing surface that cooperates with the impeller bearing. The bearing mount 144 can have a diameter and surface area sufficient to improve flow characteristics by reducing areas of potential flow stagnation or flow reversal. To further help improve flow characteristics and reduce flow reversal, the diffuser 140 can have an end cap 146 connected to or formed by the downstream end of the diffuser 140. The end cap 146 can be conical and the circumference can taper gradually to a pointed end, allowing the flow to exit the diffuser 140 in a smooth and reduced turbulence manner. In some embodiments, the downstream end of the end cap 146 can protrude from the pump housing 110, including the flow tube 111, thereby shortening the flow tube 111 and reducing manufacturing costs.

[0029] The diffuser 140 can include diffuser fins 142 that convert the rotational velocity of the flow imparted by the impeller 130 into an axial velocity and pump outlet flow. To this end, the diffuser fins 142 can include a curvature configured to gradually arrest the rotation of the flow as it exits the impeller 130. For example, the diffuser fins 142 can have a curve that, from leading edge to trailing edge, in the direction of rotation of the impeller 130, curves in opposition to the helical curvature of the impeller blades 132, starting at a steeper angle relative to the central axis, and approaching being parallel to the central axis at the downstream end of the diffuser 140. The concave, axially extending surface of the fins 142 faces in a direction opposite to that of the concave, axially extending surface of the blades 132 as shown in FIG. 2. Additionally, the embodiment shown in FIG. 2 includes only fins 142 having the same axial length.

[0030] The configuration of the fins 142 (including their spacing and shape) allows the stationary diffuser fins 142 to contact the rotating flow exiting the impeller 130 and gradually redirect that flow, such that the flow exiting the diffuser 140 has a velocity with an increased axial component relative to the flow entering the diffuser 140.

[0031] In some embodiments, the diffuser 140 may have a different number of fins (e.g., one more or one less) than the impeller 130 has blades to improve the pump assembly's resistance to thrombosis without sacrificing performance. The diffuser 140 may also include end caps 146 that improve the flow characteristics as blood exits the pump assembly 100. The end caps 146 may reduce flow reversal to provide a smoother exit flow.

[0032] The flow conditions at the transition between the impeller 130 and the diffuser 140 may be affected by the shape and size of the cavity between the impeller 130 and the diffuser 140. For example, reducing the volume of the cavity between the downstream end of the impeller 130 and the upstream end of the diffuser 140 by moving the diffuser 140 upstream toward the impeller 130 may reduce flow separation and / or flow reversal. Such a reduction may not only improve flow through the cavity, but may also reduce stress on the impeller 130 and the bearings 134 that may be caused by areas of increased pressure at the downstream end of the impeller 130 due to stagnation of flow. Higher axial stress on these components may increase friction losses in the bearings 134, which may result in higher temperatures. Increased temperatures in the pump assembly 100 may ultimately lead to blood clotting and clot formation. Thus, reducing the volume of the cavity between the impeller 130 and the diffuser 140, and the corresponding reduction in the axial force on the impeller 130, can help the pump assembly 100 operate more efficiently and without compromising blood flow.

[0033] According to one embodiment of the present disclosure shown in FIG. 6, pump assembly 600 is deployed to assist a ventricle of heart 605. For example, pump assembly 600 can be positioned in the right ventricle of heart 605 to assist heart 605 in delivering blood to another site in the patient's circulatory system. Although this disclosure describes an embodiment in which the right ventricle of heart 605 assists in delivering blood to the pulmonary artery, the present disclosure is not limited to such use. Also, aspects of the present disclosure can be used to deliver blood from any other ventricle (i.e., the left ventricle, the right atrium, or the left atrium) to another part of the circulatory system (e.g., an artery, a vein, or another ventricle).

[0034] 6 and 7 show the pump assembly 100 in place on the heart 605 and connected to further components of the device for pumping blood. For example, a controller 650 can be connected to the pump assembly 600 by a percutaneous cable 652 and / or wirelessly to provide control signals and monitor the operation of the pump assembly 600. In applications that can benefit from portability, for example when the patient is ambulatory, the controller 650 can be powered by one or more batteries 660 associated with the patient, for example via a body wear 662. The body wear 662 can be a holster, belt, or other method that allows the battery 660 to be removably supported by or on the patient's body. In applications that do not benefit from portability, power can be provided by another suitable method, such as a plug-in power supply. In some embodiments, power to some elements of the system can be provided by a direct connection to a wall outlet and one or more rechargeable batteries can be used to prevent power interruptions during power outages or during patient transport.

[0035] The pump assembly 600 shown in FIG. 8 and in an exploded view in FIG. 9 can be a rotary axial flow mechanical ventricular assist pump including a flow straightener 620, an impeller 630, and a diffuser 640, and can be implanted, for example, in the right ventricle of a patient's heart. When implanted in the right ventricle of a patient, at least a portion of the pump assembly 600 can be located directly inside the ventricle and can draw blood from the ventricle via an inlet adapter 618 (e.g., an inflow cannula) of the pump housing 610. The inlet adapter 618 can include a smooth conical tip to facilitate insertion into the ventricle. The inlet adapter 618 and pump housing 610 can generally be made from a suitable biocompatible material (such as titanium) with a finish, such as a sintered finish, that allows the inlet adapter 618 and pump housing 610 to be well integrated into the body environment. The combination of material selection and finish can help to prevent tissue incorporation into the pump assembly 600 while allowing suitable tissue in-growth.

[0036] The pump assembly 600 can include a stator 670. The stator 670 can include a non-magnetic stator housing 672 and a stator core 674. The stator 670 combines with the magnetic components of the impeller 630 to form a pump drive system. The stator 670 is the stationary portion of the pump drive system and can be made of electromagnetic components that generate a rotating magnetic field that magnetically couples to the permanent magnets contained within the impeller 630. The stator core 674 can include wire stator coils and ferromagnetic material coupled for a conventional motor configuration. The drive circuitry that generates the electrical signals that generate the rotating magnetic field can be contained within the stator housing 672 or in separate electronics.

[0037] In some embodiments, the impeller blades 632 may be formed with or each impeller blade 632 may be provided with an enclosed magnet. In some embodiments, the impeller blades 632 may be formed around a single rod-like core magnet positioned at the axis of the impeller 630. This may be a single two-pole magnet, or an assembly of four radially magnetized quadrants for a potentially more powerful and space-efficient four-pole configuration. Whichever magnet arrangement is used, the magnets may drive the impeller 630 through a brushless direct current (DC) stator 670.

[0038] In some embodiments, the pump drive system can be a reluctance motor, and rather than having a magnetic component, the impeller 630 can be made from a ferrous material, such as iron or steel, coated with a biocompatible support material. Rather than providing permanent magnets on the impeller 630, the reluctance motor can have a non-permanent magnetic pole induced in the impeller 630.

[0039] Depending on the location and polarity of the magnets and / or iron cores used in impeller 630 , stator core 674 can be positioned so that the magnetic field generated by stator core 674 drives impeller 630 .

[0040] 10 shows the flow tube 611 and stator core 674 with the stator housing 672 removed, and FIG. 11 shows the flow tube 611 with the stator core 674 removed. Cables and wires supplying power and / or signals to the stator 670 can exit the stator housing 672 through openings 676 and connect to, for example, a feedthrough 678 at the downstream end of the stator housing 672. The feedthrough 678 can allow the cables and wires to pass through the pump housing 610 while maintaining a hermetic seal that prevents ingress of blood or other bodily fluids into the electronic components of the pump assembly 600. The feedthrough 678 can be integrally formed or made of multiple components, for example, the feedthrough standoffs 678a can allow the wires to exit the pump housing 610 at a 90 degree angle, the feedthrough ports 678b can facilitate a sealed joint between the standoffs 678a and the feedthrough cover 678d, and the sealed feedthroughs 678c and feedthrough ends 678e can allow the wire sheath to be sealed to the pump housing. In some embodiments, the stator housing 672 can be generally cylindrical and can surround the stator core 674 and abut and / or couple to the flow tube 611 and / or a portion of the pump housing 610.

[0041] Returning to FIG. 8, to secure the pump assembly 600 in place, an elastic fabric or polymeric fixation ring 680 can be placed over the right ventricular insertion point, and then an adaptor ring 682 can be bonded to the elastic fabric or polymeric fixation ring 680. The fixation ring 680 can be a disc-shaped element with a central opening through which the pump assembly 600 can pass partially or completely. The fixation ring 680 can be secured to the muscle wall by a suitable method, such as suturing or bonding. The adaptor ring 682 can have a cylindrical base with a flange portion on its upstream side to allow for suturing, gluing, or otherwise bonding the adaptor ring 682 to the fixation ring 680. Because the right ventricular wall is thinner than other portions of the heart wall, e.g., the left ventricular wall, the ring bond can be double-layered for greater tissue capture and tissue protection.

[0042] The pump assembly 600 can be slid into a fixed position through a central opening in the fixation ring 680. The insertion depth can be adjusted based on the dimensions of the heart, such as the width of the right ventricle and the distance from structures such as valves, which can be determined using an image or feel. The position of the pump assembly 600 can be maintained by locking it to the adapter ring 682 using a ratcheting screw locking mechanism or other suitable mechanism to fix the position of the pump assembly 600 relative to the adapter ring 682.

[0043] The pump assembly 600 of the cardiac assist device can have an outlet adapter 619, which can be, for example, a cannula with a 90° outflow elbow. The outlet adapter 619 can include an upstream end that connects to a pump and a downstream end for connecting to a vascular graft 690 using appropriate hardware components. In some embodiments, the upstream end of the outlet adapter 619 can include a flange portion that mates with a downstream portion of the pump housing 610. In some embodiments, the direction in which the downstream end of the outlet adapter 619 points can be adjustable. For example, the outlet adapter 619 can be flexible (e.g., as a result of material properties or in an accordion-like manner like a drinking straw) to allow the downstream end to move relative to the upstream end. This structure can aid in the implantation procedure.

[0044] A flow monitoring system or other physiological monitoring system may be included in the outlet adapter 619, in the vascular graft 690, or at other suitable points along the blood flow path. For example, as shown in Figures 6, 7, and 9, a flow probe 654 may be positioned between the downstream end of the outlet adapter 619 and the vascular graft 690. Should removal or replacement of the flow probe 654 become necessary or desirable, the placement of the flow probe 654 may allow the removal / replacement to be performed without having to dissect or replace the arterial trunk.

[0045] The flow monitoring system can be used to continuously monitor the graft blood flow. The flow probe 654 can be, for example, a direct flow measurement sensor, such as an ultrasonic flow sensor, that does not require contact with blood to accurately measure flow. The ultrasonic flow probe can be used to measure the flow and pulsatile characteristics of the blood flow in real time. This information can be sent to the controller 650 and / or physician control interface. Real-time data from the flow probe can be considered in decisions made by the physician or control software to assist in pump impeller speed control or other control aspects of the system. In some embodiments, the flow monitoring system can estimate the flow rate by performing calculations based on pump operating parameters, pressure measurements, etc. Other physiological sensors, such as blood pressure sensors, temperature sensors, pulse oximetry sensors, and / or ECG sensors, can be incorporated into the device and / or system. The flow monitoring system or other monitoring devices can be placed directly on the outlet adapter 619 or at other locations downstream of the outlet adapter 619.

[0046] Flow monitoring data from the pump and sensors, including flow rate and pressure, can be incorporated into a feedback loop to either manually or automatically adjust pump settings to improve the patient's hemodynamic and physiological conditions, or to avoid adverse events occurring or worsening when the system detects an adverse event. This can allow the pump assembly 600 to respond based on flow rate and circuit inputs. The pump assembly 600 can cycle speeds and therefore adjust flow rate based on time, pulses, monitored data or algorithmic derivatives of that data (via feedback loops - automatic or manual alerts) as flow rate is related to pressure, and can also respond to clinical parameters and physiologically detected events, whether clinical or subclinical.

[0047] To protect the exposed portion of the vascular graft substitute 690, a tubular graft protection cover can be placed over all of the vascular graft substitute 690 or any exposed portion of the vascular graft substitute 690, and the downstream end of the vascular graft substitute 190 can be anastomosed to the pulmonary trunk using a vascular anastomosis suture technique or other suitable technique. The graft protection cover can provide external support to help avoid graft pressure compression from adjacent chest wall anatomical structures, thereby helping to maintain graft lumen patency. The graft protection cover can be directly connected to the adapter 619 or the downstream end of the flow probe 654 to accommodate the upstream end of the vascular graft substitute 190. The graft protection cover can be cut to customizable lengths to manage the connection points and graft length.

[0048] The cables and wires from the sensors, pump motor, and other components are combined into a percutaneous cable 652 and can be configured with an adjustable take-off angle from the downstream end of the pump assembly 600 to accommodate positioning of the pump assembly 600 in a position that can reduce pulling on the percutaneous cable 652. This can be done with a take-off joint that is flexible and pliable yet sturdy and somewhat fixable, or it can be a fixable or free-standing swivel joint. This can reduce pulling on the cables and wires as well as shear on the anatomical organs that can be punctured by excessive friction from mobility due to breathing, heartbeat, or positional pulling.

[0049] 12 and 13 are diagrams of a pump assembly 1200 and supporting components configured to circulate blood from one point in the circulatory system to another point in the circulatory system in an extracorporeal application. For example, in FIG. 12, an embodiment of the disclosure includes a system that uses the pump assembly 1200 to remove blood from a vein 1206 and circulate the blood to an artery 1207, and in FIG. 13, an embodiment of the disclosure includes a system that uses the pump assembly 1200 to remove blood from a vein 1206 and circulate the blood to a different location in the vein 1206. However, the disclosure is not limited to such applications. Aspects of the disclosure can be used to deliver blood from any blood vessel (e.g., a vein or an artery) to any other blood vessel (e.g., a vein or an artery). As mentioned above, the bypass system pump can be an axial blood pump assembly 1200 that can circulate blood through an extracorporeal circuit. The pump assembly 1200 can be used as an extracorporeal circulatory support system for procedures such as those requiring partial cardiopulmonary bypass (e.g., valvuloplasty, mitral valve revision surgery, vena cava and / or aortic surgery, liver transplantation, etc.).

[0050] A bypass pump system according to the present disclosure can include a rotary axial flow mechanical blood pump assembly 1200, a controller 1250, one or more batteries 1260, and a physician control interface 1256 that enables extracorporeal circulatory support. Such a system can be used, for example, during procedures that do not require full cardiopulmonary bypass (e.g., valvuloplasty, mitral valve revision surgery, vena cava and / or aortic surgery, liver transplantation, etc.).

[0051] In both ventricular and extracorporeal applications, a physician control interface 1256, such as an external console, can be connected (via a wired or wireless connection) to the controller 1250 and / or one or more sensors to acquire, display, and / or record pump operating parameters such as speed, blood flow rate, power usage, and battery charge. Console data can be exported for analysis and review of the system's operating parameter history.

[0052] The interface board can act as a communications hub between the system controller and a physician control interface 1256. The physician control interface 1256 can be used by a physician or other healthcare provider to manage and monitor pump speeds and settings.

[0053] The control interface may include a graphical user interface (GUI) and may further include its own independent power source. The control interface may take the form factor of a computer tablet running software including the GUI, and the interface may acquire, display, and record pump operating parameters such as speed, blood flow rate, power usage, and battery charge remaining. The control interface may display pump operating parameters and allow monitoring and adjustment of pump parameters by a physician or clinical team. In some embodiments, parameters such as flow rate and information from the sensors and pump may be sent to a controller for wireless streaming data transmission, so that they can be accessed in real time by a secure web-based access system.

[0054] In some embodiments, the cartridge, front bearing mount / rectifier, impeller, and diffuser can be machined and polished from a suitable medical grade material, such as titanium or a titanium alloy (e.g., grade 23 titanium). The internal bearing that supports the rotational motion of the impeller can be made from a bearing material, such as silicon carbide and / or zirconia ceramic for long-term applications, or from a polymer / composite material with sufficient wear characteristics for short-term applications. In some embodiments, one or more of the cartridge, front bearing mount / rectifier, impeller, and diffuser can be formed from a material, such as a polymer or other metal, and then coated with a suitable biocompatible bearing material. Such a configuration can allow the components to directly contact each other without the need for a separate bearing structure. For example, one or more of these components can be injection molded with a polymer, then the bearing surfaces are machined into the molded part, and then the components are coated with a ceramic material.

[0055] FIG. 14 is an exploded cross-sectional view of a pump assembly 1400 configured for extracorporeal use, according to an embodiment of the present disclosure.

[0056] The extracorporeal blood pump system of FIG. 14 can include a disposable blood pump cartridge including a pump housing 1410 and internal blood contacting components (e.g., flow straightener 1420, impeller 1430, and diffuser 1440) in combination with a reusable stator 1470. The disposable components can be connected to the patient via cannulation and tubing as required for the particular clinical therapy being utilized. For example, the inlet adapter 1418 and the outlet adapter 1419 can be barbed tubing connectors. The blood circuit can include an oxygenation system or other systems for extraction or infusion of other therapeutic components of the blood stream. In some embodiments, the pump cartridge can include a permanent magnet externally coupled to the reusable stator 1470. As described above, the stator 1470 provides the electromagnetic force that rotates the impeller 1430 to operate the pump mechanism.

[0057] 15A and 15B are perspective views of an embodiment of a reusable stator 1470 in an open and closed state, respectively. To provide more flexibility with respect to installation, assembly, and maintenance, the stator 1470 may also be clipped or otherwise assembled to the outside of the pump housing 1410. This external attachment method may aid in assembly of the bypass system by allowing the stator 1470 to be selectively engaged with the pump housing 1410 before or after the pump assembly 100 is connected to the patient's circulatory system. This selective engagement, without the requirement that the pump housing 1410 be uncoupled, may allow sterility to be maintained throughout coupling and uncoupling of the stator 1470.

[0058] The reusable stator 1470 can include a stator housing 1472, a stator core 1474, and a hinge 1473. The stator 1470 can utilize a clamshell design that facilitates insertion of the pump housing 1410, especially when the stator 1470 is connected to a patient. A portion of the stator housing 1472 and the stator core 1474, e.g., a semicircular portion, can pivot or otherwise articulate to an open position relative to another portion of the stator housing 1472 and the stator core 1474. Each portion of the stator core 1474 can be electrically connected using flexible wire that can bend with the assembly while the stator core 1474 is hinged open, and / or can include electrical contacts that separate when the stator 1470 is opened and reconnect when the stator 1470 is closed. A series resistor can be added to give each coil of the stator core 1474 similar electrical characteristics despite any additional wire length required to connect the stator halves. In some embodiments, a controller for the pump assembly 1400 can detect the state / position of the stator 1470, for example, using the back electromagnetic force (EMF) measured from a coil or using a separate sensor.

[0059] With the stator 1470 in the open position, the stator 1470 can be positioned around the pump housing 1410 and / or the pump housing 1410 can be positioned inside the stator 1470. The stator 1470 can be aligned with the appropriate portions of the pump housing 1410 and impeller 1430 using physical and / or visual indicators. For example, in some embodiments, the stator 1470 can be positioned to abut the flange portion 1413 when properly positioned, or the flange portion 1413 can fit into a cooperating recess in the stator housing 1472.

[0060] Once the pump housing 1410 is inserted, the stator 1470 is closed to form a circumferential ring around the impeller 1430 to generate a rotating magnetic field that drives the pump assembly 1400 as needed. The hinged stator 1470 can then be secured in place with suitable mechanical fasteners such as screws, bolts, clips, clamps, or latches. In some embodiments, the stator cartridge is a one-piece component that is slid onto or otherwise removably attached to the cartridge prior to connection to the patient's circulatory system.

[0061] In some embodiments, the stator 1470 can be a brushless direct current (DC) stator and can include an anodized aluminum stator housing 1472 with an iron inner core 1474. Because the stator 1470 does not come into direct contact with the bloodstream, it can be washed / autoclaved and made reusable.

[0062] FIG. 16 is a side view of the pump assembly 1600 (including the flow straightener 1620, impeller 1630, and diffuser 1640) with a tube expander 1616 attached, and FIG. 17 is a cross-sectional view of the pump assembly 1600 with the tube expander 1616 attached to allow for more precise positioning of the pump mechanism within the pump cartridge. The tube expander 1616 can be an internally threaded tube with fine pitch threads 617, such as a 48 pitch thread, and can mate with complementary threads on the threads 1612 of the pump housing 1610. The fine threads on the threads 1612 and 1617 can allow for precise adjustments to achieve repeatable and precise operating clearance specifications for the bearings. The tube expander 1616 can abut against a flange 1613 (or other reference point) and can urge the threads 1612 of the pump housing 1610 towards the flange 1613 to create a pull that can modify the dimensions of the flow tube.

[0063] During manufacture and assembly of the flow tube, a torque applied to the tube expander 1616 can apply sufficient tension to the pump housing 1610 to move the flow straightener 1620, including the bearing mount 1624, to a position that is a predetermined distance away from the flange portion 1613. This applied tension can maintain adequate clearance to reduce friction and wear on the bearing mounts 1624 and 1644 and the bearing 1634 for smooth rotational motion of the impeller 1630. The tube expander 1616 can maintain its position by friction between the tube expander 1616 and the threads and / or flanges, or can be secured via other suitable methods, such as an external locking mechanism. The clearance between the internal components can range from about 0.0001 to about 0.001 inches (about 0.0025 to 0.025 mm), and the tube expander 1616 can be adjustable to provide an adjustable spacing between the mount 1624 and the flange portion 1613 of about 0.00005 to 0.0005 inches (about 0.00125 to 0.0125 mm). The tube expander 1616 can be made from a material such as stainless steel, and the tube expander 1616 can be an outer component of the flow tube so that the tube expander 1616 will not come into contact with blood.

[0064] FIG. 18 is a plot of head pressure ("H") generated by a pump assembly 100 according to an embodiment of the present disclosure as a function of flow rate ("Q") through the pump. To evaluate pump performance, a pump curve can be plotted based on pump design and pump speed. The pump curve can be characteristic of a particular pump design and geometry and can be a plot of head pressure ("H") generated by a pump as a function of flow rate ("Q") through the pump. The pump curve plotted in FIG. 18 illustrates the performance of a pump according to an embodiment of the present disclosure when incorporated into a cannula circuit, for example as a bypass pump. The illustrated slope indicates that for a given pump speed, the pressure head does not decrease significantly as the flow rate increases. The plotted curve also indicates that the pump assembly 100 according to the present disclosure can achieve a continued parallel incremental performance with speed as the head pressure increases.

[0065] In some applications, the required high pressure rise (e.g., comparable to 150 mmHg@4 lt / m) may require multiple impeller 130 elements. A single stage impeller 1300 may achieve peak efficiency at about 9,500 rpm and a flow rate of about 4 lt / m. In such an embodiment, a rotational speed of about 13,000 rpm may be required to achieve a pressure rise of about 150 mmHg. Impeller speeds beyond the efficient range of a particular impeller design may cause flow problems such as flow separation bubbles / cavitation, so a multi-stage pump assembly 200 may be desired. FIG. 19 is a schematic diagram of a multi-stage pump assembly 1900 according to an aspect of the present disclosure. The multi-stage pump assembly 1900 may include multiple impellers 1930 and diffusers 1940 in series within a pump housing 1910 to achieve high pressures and flow rates while reducing the required rotational speed. The impellers 1930 can be used in tandem, either stacked or in series, to provide the flow rate to pressure flow requirements for a particular blood flow application.

[0066] The multi-stage pump assembly 1900 can provide the necessary blood flow rate through a high pressure oxygen supply system. Normal arterial blood pressure can range from about 60 mmHg to about 130 mmHg, but the addition of an oxygen supply system can require a pump capable of delivering flow against pressures of about 300 mmHg or more.

[0067] The multi-stage pump assembly 1900 can include three impeller-diffuser stages to provide the required blood flow rate in a high pressure patient oxygen delivery system. The blades can be designed to allow the multiple impellers 1930 to be near their peak efficiency while minimizing blood compression. For example, four impeller blades can be used for each impeller 1930 and five diffuser fins can be used for each diffuser 1940, with the impeller blades and diffuser fins having similar designs as described with respect to other disclosed embodiments. As with the single stage impeller application, the impellers 1930 and diffusers 1940 can be located on a single rigid shaft 1950.

[0068] The shaft may be comprised of an upstream section 1960, a center section 1970, and a downstream section 1980, with the upstream section including the first impeller 1930a and the center section including the remaining two impellers 1930b and 1930c. The reduced diameter joints between each shaft section may allow for the use of journal bearings 1944 to support the shaft in the radial dimension. In some embodiments, the first and third diffusers 1940a and 1940c may be an integral part of the journal bearing 1944, which may be coupled to the non-rotating outer housing 1910. Support for the shaft in the axial direction may be provided by a thrust bearing component 1948 located within the third diffuser 1940c upstream of the end cap 1946. In some embodiments, the second diffuser 1940b may not include a bearing if the journal bearing 1944 provides sufficient support. The second diffuser 1940b has an axial through passage and may be of a split case design in that it only connects to the pump housing 1910.

[0069] The connection between each shaft section can be press fit, threaded, laser welded, or adhesively bonded, with the choice being dictated by structural integrity, motor encapsulation, and other manufacturing considerations, etc.

[0070] The rotating shaft of the multi-stage pump assembly 1900 may be driven by electromagnetic forces between a permanent motor magnet 1990 located in the shaft 1950 and a stator (not shown) located in or around the pump housing 1910. The magnet 1990 may be a single permanent magnet for a two-pole motor design or a series of radially magnetized magnets or magnet quadrant sections for a four-pole magnet design. As with the single stage embodiment, a tube expander mechanism may be used on the pump housing 1910 to ensure proper component alignment and spacing.

[0071] It will be apparent to those skilled in the art that various modifications and variations can be made in the disclosed systems and methods without departing from the scope of the present disclosure. It should be appreciated that the disclosed systems can include various suitable computer systems and / or computing units incorporating multiple hardware components, such as a processor and a non-transitory computer-readable medium, that enable the system to perform one or more tasks during the methods according to the embodiments described herein. Other aspects of the present disclosure will be apparent to those skilled in the art from a consideration of the details and examples of the features disclosed herein. The details and examples are intended to be considered as illustrative only.

[0072] The pump assemblies and their various associated components and peripherals can be programmed and / or controlled via any suitable components, including computing devices, hardware, software, and associated peripherals or other components. This portion of the specification describes examples of such components. For example, various pump systems can include any computing device. The computing device can include input and output ports for connecting with input and output devices such as a keyboard, mouse, touch screen, monitor, display, etc. Of course, various system functions can be distributed and implemented on several similar platforms to distribute the processing load. Alternatively, the system can be implemented by suitable programming of one computer hardware platform.

[0073] In one embodiment, any of the disclosed systems, methods, and / or graphical user interfaces can be executed or implemented by a computing system consistent with or similar to the description herein. Although not required, aspects of the present disclosure are described in the context of computer-executable instructions, such as routines executed by a data processing device, e.g., a server computer, a wireless device, and / or a personal computer. Those skilled in the art can recognize that aspects of the present disclosure can be implemented in other communication, data processing, or computer system configurations, including Internet appliances, handheld devices (including personal digital assistants ("PDAs")), wearable computers, cellular or mobile phones of any kind (including voice-over-IP ("VoIP") phones), dumb terminals, media players, gaming devices, virtual reality devices, multiprocessor systems, microprocessor-based or programmable consumer electronics, set-top boxes, network PCs, minicomputers, mainframe computers, and the like. In fact, the terms "computer," "computing device," and the like are generally used interchangeably herein to refer to any of the above devices and systems, as well as any data processors.

[0074] Aspects of the disclosure may be embodied in special purpose computers and / or data processors that are specifically programmed, configured, and / or constructed to execute one or more of the computer-executable instructions detailed herein. Although aspects of the disclosure, such as certain functions, are described as being performed exclusively on a single device, the disclosure may also be implemented in a distributed environment in which functions or modules are shared among separate processing devices that are linked via a communications network, such as a local area network ("LAN"), a wide area network ("WAN"), and / or the Internet. Similarly, techniques presented herein as involving multiple devices may be implemented on a single device. In a distributed computing environment, program modules may be located in both local and / or remote memory storage devices.

[0075] Aspects of the present disclosure may be stored and / or distributed on non-transitory computer readable media, including magnetically or optically readable computer disks, hardwired or preprogrammed chips (e.g., EEPROM semiconductor chips), nanotechnology memories, biological memories, or other data storage media. Alternatively, computer-implemented instructions, data structures, screen displays, and other data according to aspects of the present disclosure may be distributed on propagating signals on a propagating medium (e.g., electromagnetic waves, sound waves, etc.) over a period of time, over the Internet and / or other networks (including wireless networks), and / or may be presented on any analog or digital network (packet-switched, circuit-switched, or otherwise).

[0076] Program aspects of the technology can be considered as a "product" or "article of manufacture" that is typically in the form of executable code and / or associated data carried on or embodied in a type of machine-readable medium. "Storage" type media includes some or all of the tangible memory of a computer, processor, etc., or its associated modules, such as various semiconductor memories, tape drives, disk drives, etc., that can provide non-transitory storage for software programming at any time. All or part of the software can sometimes be communicated over the Internet or various other telecommunications networks. Such communication can enable the software to be retrieved from one computer or processor to another, for example, from a management server or host computer of a mobile communication network to a server's computer platform and / or from a server to a mobile device. Thus, other types of media that can have software elements include light waves, radio waves, and electromagnetic waves, such as those used at the physical interfaces between local devices, over wired and optical fixed line networks, and in various air links. The physical elements that carry such waves, such as wired or wireless links, optical links, etc., can also be considered media that have software. As used herein, unless limited to non-transitory tangible "storage" media, terms such as computer or machine "readable medium" refer to any medium that participates in providing instructions to a processor for execution.

[0077] It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed systems, methods, and apparatus without departing from the scope of the disclosure. Other embodiments of the present disclosure will be apparent to those skilled in the art from consideration of the details and examples of the invention disclosed herein. It is intended that the details and examples be considered as exemplary, with the true scope and spirit of the invention being indicated by the following claims. Other embodiments of the invention are described below. [Embodiment 1] 1. An apparatus for pumping blood, comprising: a pump housing having an outer wall radially disposed about a longitudinal pump axis and having an upstream end and a downstream end; a blood flow straightener having a plurality of fins, the blood flow straightener being disposed at the upstream end of the pump housing and fixed to the pump housing by the plurality of fins; a diffuser having a plurality of diffuser fins positioned at the downstream end of the pump housing and secured to the pump housing by the plurality of diffuser fins; an impeller positioned within the pump housing between the flow straightener and the diffuser, the impeller including a plurality of impeller blades; a pump drive device positioned circumferentially around the impeller and configured to impart rotational motion to the impeller by applying a magnetic field to the impeller; Equipped with The apparatus, wherein the impeller is supported by an upstream bearing cooperating with an upstream bearing mount of the blood flow straightener and a downstream bearing cooperating with a downstream bearing mount of the diffuser. [Embodiment 2] 2. The device of embodiment 1, further comprising an outlet adapter coupled to the downstream end of the pump housing for directing blood exiting the pump housing. [Embodiment 3] An apparatus as described in embodiment 1, wherein the multiple fins have a teardrop-shaped cross-section with a curved upstream edge and a pointed downstream edge. [Embodiment 4] 2. The apparatus of claim 1, wherein the plurality of impeller blades includes a plurality of spirally wound blades having a first pitch in an upstream portion of the impeller that is smaller than a second pitch in a downstream portion of the impeller. [Embodiment 5] The apparatus of embodiment 4, wherein the plurality of impeller blades further includes a plurality of arcuate blades positioned between the plurality of spirally wound blades at a downstream portion of the impeller, each of the arcuate blades extending along the longitudinal pump axis a distance less than the distance each of the impeller blades extends along the longitudinal pump axis. [Embodiment 6] 2. The device of embodiment 1, wherein the diffuser is positioned downstream of the plurality of diffuser fins and includes a conical end cap having a pointed end. [Embodiment 7] Power supply, A control device in communication with the power source; Further equipped with The apparatus of embodiment 1, wherein the pump drive device includes a stator, the pump drive device being electrically connected to the power source and the control device to selectively supply power to the stator. [Embodiment 8] 8. The apparatus of claim 7, wherein the stator is integral with the pump housing. [Embodiment 9] 8. The apparatus of claim 7, wherein the stator includes a hinge and is configured to selectively engage the pump housing by articulating the hinge. [Embodiment 10] The device of embodiment 7, wherein the power source is a battery, and the battery and the control device are configured to be removably coupled to a patient. [Embodiment 11] The device of embodiment 1, wherein the outer wall of the pump housing includes an external threaded portion and a flange portion, and the tube expander is configured to modify the dimensions of the pump housing by screwing into the external threaded portion and abutting against the flange portion. [Embodiment 12] 1. An apparatus for pumping blood, comprising: a pump housing having an outer wall radially disposed about a longitudinal pump axis and having an upstream end and a downstream end; a flow straightener positioned at the upstream end of the pump housing, the flow straightener having a plurality of fins; a diffuser positioned at the downstream end of the pump housing, the diffuser having a plurality of diffuser fins; an impeller positioned within the pump housing between the flow straightener and the diffuser, the impeller including a plurality of impeller blades; a stator cartridge including a stator housing and a stator core; Equipped with The apparatus, wherein the stator cartridge is removably positioned circumferentially about the pump housing and configured to impart rotational motion to the impeller by applying a magnetic field to the impeller. [Embodiment 13] The device of embodiment 12, wherein the stator cartridge includes a first portion, a second portion, and a hinge having an open state and a closed state, and when the hinge is articulated between the open state and the closed state, the first portion pivots relative to the second portion to selectively engage the stator cartridge with the pump housing. [Embodiment 14] The apparatus of embodiment 12, wherein the stator housing comprises a non-magnetic material, the stator core comprises a magnetic material, and the impeller comprises one or more magnets. [Embodiment 15] Power supply, A controller coupled to the power source; Further equipped with 13. The apparatus of claim 12, wherein the stator cartridge is electrically connected to the power source and the control device and selectively powers the stator core to generate the magnetic field. [Embodiment 16] The device of embodiment 15, wherein the control device supplies direct current to the stator cartridge and the stator core is a brushless stator type. [Embodiment 17] 1. An apparatus for pumping blood, comprising: a pump housing having an outer wall radially disposed about a longitudinal pump axis, the pump housing having an upstream end and a downstream end, external threads between the upstream end and the downstream end, and a flange extending radially outward from the outer wall; a flow straightener positioned at the upstream end of the pump housing, the flow straightener having a plurality of fins; a diffuser positioned at the downstream end of the pump housing, the diffuser having a plurality of diffuser fins; an impeller positioned within the pump housing between the flow straightener and the diffuser, the impeller including a plurality of impeller blades; a pump drive positioned circumferentially about the outer wall and configured to impart rotational motion to the impeller; a tube expander configured to thread onto the male threaded portion and abut the flange portion to modify the size of the pump housing; An apparatus comprising: [Embodiment 18] 18. The device of claim 17, wherein the dimension of the pump housing that is modified by the tube expander is the axial length of a portion of the pump housing between the male threaded portion and the flange portion. [Embodiment 19] The device of embodiment 18, wherein when the tubal expander is screwed into the male threaded portion of the pump housing, one or more gaps between the impeller and the blood flow straightener or the diffuser are between 0.0025 mm and 0.025 mm. [Embodiment 20] 18. The apparatus of claim 17, wherein the flange portion extends from the outer wall between the male threaded portion and the downstream end. [Explanation of symbols]

[0078] 1410 Pump housing 1413 Flange part 1418 Inlet Adapter 1419 Outlet Adapter 1420 rectifier 1430 Impeller 1440 Diffuser 1470 Stator 1472 stator housing 1474 Stator core

Claims

[Claim 1] 1. An apparatus for pumping blood, comprising: a pump housing having an outer wall radially disposed about a longitudinal pump axis and having an upstream end and a downstream end; a blood flow straightener having a plurality of fins, the blood flow straightener being disposed at the upstream end of the pump housing and fixed to the pump housing by the plurality of fins; a diffuser having a plurality of diffuser fins positioned at the downstream end of the pump housing and secured to the pump housing by the plurality of diffuser fins; an impeller positioned within the pump housing between the flow straightener and the diffuser, the impeller including a plurality of impeller blades; a pump drive device positioned circumferentially around the impeller and configured to impart rotational motion to the impeller by applying a magnetic field to the impeller; Equipped with The apparatus, wherein the impeller is supported by an upstream bearing cooperating with an upstream bearing mount of the blood flow straightener and a downstream bearing cooperating with a downstream bearing mount of the diffuser.

Images