Blood pump with cantilevered impeller
Patent Information
- Application Number
- JP2024550188
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-02-25
- Filing Date
- 2023-02-27
- Publication Date
- 2025-03-13
Smart Images
Figure 2025506816000001_ABST
Abstract
Description
[Technical field]
[0001] CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of priority to U.S. Application No. 63 / 268,503, filed February 25, 2022, the entire contents of which are incorporated by reference herein. Incorporation by Reference
[0002] All publications and patent applications mentioned in this specification are herein incorporated by reference in their entirety to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference. [Background technology]
[0002]
[0003] Patients with heart disease may have severely impaired ability to pass blood flow through their heart and vascular system, presenting substantial risks during corrective procedures such as balloon angioplasty and stent delivery. Intra-aortic balloon pumps (IABPs) are used to support circulatory function, such as treating patients with heart failure. IABPs are typically placed in the aorta and inflated and deflated in a counterpulsation fashion with heart contractions, with one function being to provide additional support to the circulatory system. The use of IABPs is common in treating patients with heart failure, such as supporting patients during high-risk percutaneous coronary interventions (HRPCI), stabilizing patient blood flow after cardiogenic shock, treating patients associated with acute myocardial infarction (AMI), or treating decompensated heart failure. Such circulatory support may be used alone or in combination with drug therapy.
[0003]
[0004] Catheter blood pumps have been known for decades to support hemodynamically unstable patients. Catheter blood pumps are inserted into the body in connection with the cardiovascular system to pump arterial blood from the left ventricle into the aorta to add to the natural blood pumping capacity of the left side of the patient's heart. Another known method is to pump venous blood from the right ventricle into the pulmonary artery to add to the natural blood pumping capacity of the right side of the patient's heart. The overall purpose is to reduce the load on the patient's myocardium in order to stabilize the patient, such as during a medical procedure that may place additional stress on the heart, to stabilize the patient before a heart transplant, or for continued support of the patient.
[0004]
[0005] One such blood pump, the hemo pump, was developed in the 1980s as the first percutaneous blood pump. The hemo pump included a rotary pump guided by a catheter with a long flexible inflow extension. The hemo pump had an axial flow design to improve flow efficiency for a given catheter profile. The hemo pump was expanded into several sizes. However, the smaller size of 14 Fr required surgical vessel dissection and resulted in inadequate flow. The 21 Fr version increased the risk of complications and limited additional flow.
[0005]
[0006] Efforts have been made to provide higher flow while limiting the catheter's introduction profile. Examples include the expandable pump shown in U.S. Patent No. 5,749,855 to Reitan ("the '855 patent"). The '855 patent describes an expandable impeller within a protective outer filament. The impeller blades are hinged to allow the entire pump to be folded for introduction and expanded within the body. However, hydraulic efficiency is compromised because the impeller rotates within the large vessels and therefore cannot generate pressure to create flow.
[0006]
[0007] Other examples include U.S. Patent No. 7,393,181 to McBride ("the '181 patent"), U.S. Patent No. 9,446,179 to Keenan ("the '179 patent"), U.S. Patent No. 9,512,839 to Liebing ("the '839 patent"), and U.S. Patent No. 6,533,716 to Schmitz-Rode ("the '716 patent"). All of these references describe expandable pumps formed with an expandable impeller within an expandable shroud. However, these pumps involved complex designs.
[0007]
[0008] For example, the '716 patent provides a design with an unsupported flow lumen. With no support in the flow lumen, the blood pump lacks hydraulic efficiency and runs the risk of the impeller rubbing or contacting the inner diameter of the flow lumen. The '181 patent and similar pumps require the drive shaft to extend through the impeller and terminate in a bearing at the distal end of the shroud. Both the '179 patent and the '839 patent describe distal bearings in the shroud. Each of these requires additional moving parts, which increases the risk of hemolysis and thromboembolic events. The additional structure(s) also add or lengthen areas of increased stiffness within the pump, making it difficult to install and making the pump stiff across the aortic valve and within the ventricle. The '839 patent also involves placing a high speed impeller within the ventricle, which is believed to create a risk of complications. Summary of the Invention [Problem to be solved by the invention]
[0008]
[0009] There is a need for a true percutaneous pump that can provide adequate cardiac support for a variety of heart failure populations. There is a need for a pump that is easy to introduce and track and is anatomically compatible. There is a need for a pump with reduced risk of injury and complications. [Means for solving the problem]
[0009]
[0010] The present disclosure relates to intravascular blood pumps and methods of their use.
[0011] An expandable catheter blood pump is provided that includes a catheter-supported blood conduit, the blood conduit comprising an expandable scaffold and an impermeable membrane disposed over a portion of the expandable scaffold, and an impeller assembly rotatably supported within a proximal portion of the blood conduit, the impeller assembly being the only structure positioned within the blood conduit.
[0010]
[0012] In some embodiments, the impeller assembly includes one or more impeller blades coupled to an impeller shaft.
[0013] In one embodiment, the impeller shaft passes through an impeller bearing assembly proximate to the one or more impeller blades.
[0011]
[0014] In some embodiments, the impeller bearing assembly is positioned at least partially within the proximal hub of the blood pump.
[0015] In one embodiment, the blood pump further includes a flexible drive cable coupled to the proximal end of the impeller shaft.
[0012]
[0016] In some embodiments, the impeller shaft is stiffer than the flexible drive cable.
[0017] In one embodiment, the impeller assembly is cantilevered.
[0013]
[0018] In some embodiments, there are no structures located distal to the impeller assembly within the blood conduit.
[0019] In one embodiment, the blood conduit includes an open lumen distal to the impeller assembly.
[0014]
[0020] In some embodiments, the blood pump does not have a bearing located distal to the impeller assembly.
[0021] In one embodiment, the impeller assembly is disposed in the outlet section of the expandable scaffold.
[0015]
[0022] In some embodiments, the exit section includes a plurality of proximal struts that form at least one opening.
[0023] In one embodiment, the at least one opening is located proximal to the proximal end of the impermeable membrane.
[0016]
[0024] In some aspects, the impeller assembly is disposed at least partially within the outlet region.
[0025] In some embodiments, the expandable section further comprises a central portion distal to the impeller assembly.
[0017]
[0026] In one embodiment, the central portion is more flexible than the exit section.
[0027] In some embodiments, the catheter further comprises a distal shaft section coupled to the exit section.
[0018]
[0028] In one embodiment, the distal shaft section is more flexible than the exit section.
[0029] An expandable catheter blood pump is provided that includes a blood conduit supported by a catheter, the blood conduit comprising an expandable scaffold and an impermeable membrane disposed over the expandable scaffold, the expandable scaffold including five separate sections including: a) a plurality of distal struts forming an inlet section, b) a distal shroud section, c) a central shroud section, d) a proximal shroud section, and e) a plurality of proximal struts forming an outlet section, and an impeller disposed within the proximal shroud section and rotatably supported by a drive cable assembly that extends through the catheter, through the outlet section, and into the proximal shroud section, the drive cable assembly being more flexible proximal of the outlet section than it is through the outlet section and the proximal shroud section.
[0019]
[0030] In some embodiments, the drive cable assembly does not extend distally into the central shroud section.
[0031] In some embodiments, the impeller and drive cable assembly is not located in the central shroud section, the distal shroud section, or the inlet section.
[0020]
[0032] In one embodiment, the drive cable assembly includes a flexible drive cable coupled to a rigid impeller shaft.
[0033] In some embodiments, the flexible drive cable is coupled to a rigid impeller shaft proximal to the impeller bearing assembly.
[0021]
[0034] In one embodiment, the flexible drive cable is more flexible than the rigid impeller shaft.
[0035] In some embodiments, the drive cable assembly and impeller are cantilevered.
[0022]
[0036] In some embodiments, there are no structures positioned within the blood conduit, except for the impeller and drive cable assembly.
[0037] An expandable catheter blood pump is provided comprising: a catheter shaft; a proximal hub assembly coupled to the catheter shaft; a blood conduit supported by the proximal hub, the blood conduit comprising an expandable scaffold and an impermeable membrane disposed on the expandable scaffold, the expandable scaffold comprising an inlet section, a central section, and an outlet section; a cantilevered impeller assembly disposed at least partially in the outlet section, the cantilevered impeller assembly including a drive assembly extending through the catheter shaft and the impeller assembly; and a distal tip coupled to the inlet section, wherein the distal tip, central section, and catheter shaft are more flexible than the inlet section and the outlet section, and the blood pump is configured to flex within the distal tip, central section, and / or catheter shaft in response to a force applied to the blood pump.
[0023]
[0038] In some embodiments, the outlet section and drive assembly are sufficiently rigid to maintain a tip gap between the impeller assembly and the blood conduit when a force is applied to the blood pump.
[0024]
[0039] In some embodiments, the drive assembly is more flexible within the catheter shaft than it is in the exit section.
[0040] In one embodiment, the drive assembly includes a flexible drive cable within the catheter shaft and an impeller shaft within the exit section.
[0025]
[0041] In some aspects, the impeller shaft passes through the impeller bearing assembly.
[0042] In some embodiments, the drive assembly does not extend distally into the central section.
[0026]
[0043] In one embodiment, the impeller assembly and the drive assembly are not located in the central section or inlet section.
[0044] A catheter blood pump is provided that includes a blood conduit supported by a catheter, the blood conduit comprising an expandable scaffold and an impermeable membrane and having a substantially constant diameter, and an impeller rotatably supported within a proximal portion of the blood conduit, the impeller having a diameter that decreases from a proximal end of the impeller to a distal portion of the impeller, the blood pump being configured to rotate the impeller within the blood conduit to pump blood from a blood pump input to a blood pump outlet. [Brief description of the drawings]
[0027] [Figure 1A]
[0045] FIG. 1 is a side view of an exemplary blood pump including an expandable scaffold supporting a blood conduit in which an impeller is housed. [Figure 1B] FIG. 1 is a side view of an exemplary blood pump including an expandable scaffold supporting a blood conduit in which an impeller is housed. [Diagram 2]
[0046] FIG. 2 shows a catheter shaft portion of a blood pump. [Diagram 3]
[0047] FIG. 1 illustrates a blood pump scaffold and blood conduits. [Figure 4]
[0048] FIG. 2 is a cutaway view of the outlet area of the blood pump. [Diagram 5]
[0049] FIG. 2 shows the distal hub of the blood pump. [Figure 6]
[0050] FIG. 2 shows the distal tip of the blood pump. [Figure 7]
[0051] FIG. 2 is a cutaway view of an impeller in the outlet region of a blood pump. [Figure 8A]
[0052] FIG. 8A illustrates the deflection of a blood pump in response to a force applied to the blood pump. [Figure 8B] FIG. 8B illustrates the deflection of the blood pump in response to a force applied to the blood pump. [Figure 9]
[0053] FIG. 1 illustrates one embodiment of a tapered impeller for a blood pump. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0028]
[0054] For example, a minimally invasive rotary blood pump is provided that may be inserted into the body in connection with the cardiovascular system to pump arterial blood from the left ventricle into the aorta to add to the natural blood pumping capacity of the left side of the patient's heart. The overall purpose of using such a blood pump is to reduce the load on the patient's myocardium in order to stabilize the patient, such as during a medical procedure that may place additional stress on the heart, to stabilize the patient prior to a heart transplant, or for continued support of the patient.
[0029]
[0055] FIG. 1A illustrates an example of an intravascular blood pump 100. The blood pump 100 includes an expandable / collapsible blood conduit 102 configured to transition between an expanded state as shown in FIG. 1A and a collapsed state (not shown). For example, the conduit 102 may be in a collapsed state when confined within a delivery catheter for delivery to the heart, expanded upon release from the delivery catheter for blood pumping, and collapsed back within the delivery catheter (or other catheter) for removal from the heart. When in the expanded state, the conduit 102 may be radially expanded to form an inner lumen for blood to pass through. When in the expanded state, the inner lumen of the conduit 102 may be configured to accommodate blood pumped by an impeller disposed therein.
[0030]
[0056] In this example, blood pump 100 includes an impeller 104 in a proximal portion of conduit 102. Conduit 102 includes a first (e.g., proximal) end having a first (e.g., proximal) opening 101 and a second (e.g., distal) end having a second (e.g., distal) opening 103. First opening 101 may be configured as an outlet and second opening 103 may be configured as an inlet for blood. For example, blood may enter conduit 102 primarily through second (e.g., distal) opening 103 and exit conduit 102 primarily through first (e.g., proximal) opening 101. In such a case, second opening 103 acts as a blood inlet and first opening 101 acts as a blood outlet. Impeller 104 may be configured to pump blood from the inlet toward the outlet. In an exemplary operating position, the second opening 103 (e.g., the inlet) can be within the left ventricle, distal to the aortic valve, and the first opening 101 (e.g., the outlet) can be proximal to the aortic valve (e.g., in the ascending aorta).
[0031]
[0057] The exemplary conduit 102 includes a tubular expandable / collapsible scaffold 106 that provides structural support for a membrane 108 covering at least a portion of the inner and / or outer surface of the scaffold 106. The scaffold 106 defines a supported lumen or blood conduit with radial strength to maintain blood flow during operation of the blood pump. The exemplary conduit is formed to be fluid impermeable by the membrane. The membrane may be attached to the scaffold, cover the scaffold, sandwiched or molded around the scaffold, or integrated into the scaffold, or other configurations as will be understood by those skilled in the art from the description herein. The exemplary scaffold 106 includes a material having a pattern of openings or multiple openings with the membrane 108 covering the openings to retain blood within the lumen of the conduit 102. The scaffold 106 may be unitary and made of a single piece of material. For example, the scaffold 106 may be formed by cutting (e.g., laser cutting) a tubular material. Exemplary materials for the scaffold 106 may include one or more of nickel titanium (nitinol), cobalt alloy, and a polymer, although other materials may be used.
[0032]
[0058] The exemplary scaffold 106 includes proximal struts 112a extending at a proximal end near the first opening 101 (e.g., blood outlet region) and distal struts 112b extending from the scaffold 106 near the second opening 103 (e.g., blood inlet region). The proximal struts 112a are coupled to a first hub 114a of the catheter shaft 110. The distal struts 112b are coupled to a second hub 114b. The second or distal hub 114b can be coupled, connected, or integral with an atraumatic distal tip 116. The distal tip 116 can be highly flexible and pliable. In some examples, the distal tip can include a distal bend or curve, such as a J-tip, pigtail tip, or the like. In this example, the first hub 114a includes a bearing assembly through which a central drive cable extends. The drive cable is operatively coupled to and configured to rotate the impeller 104 .
[0033]
[0059] The conduit 102 has a proximal region 118, a central region 120, and a distal region 122. The central region 120 may be configured to be positioned across a valve (e.g., the aortic valve) such that the proximal region 118 is configured to be positioned at least partially within a first heart region (e.g., the ascending aorta) and the distal region 122 is at least partially within a second heart region (e.g., the left ventricle). The proximal region 118 may be configured to house an impeller therein. As shown, the blood conduit 102 may have a substantially constant diameter.
[0034]
[0060] The distal tip 116, the conduit 102, and the shaft 110 may each include areas of increased flexibility (e.g., less stiffness) relative to other areas of the blood pump. The areas of increased flexibility may be configured to deflect or bend when a load is applied to the blood pump 100. In some implementations, the distal shaft portion 111 of the shaft 110, the central region 120 of the conduit 102, and the distal tip area 113 of the distal tip 116 are the most flexible areas or areas of the blood pump 100.
[0035]
[0061] 1A, the shaft 110 may include a distal shaft portion 111 that is more flexible than other sections of the shaft 110. The distal shaft portion 111 may achieve increased flexibility by having a reduced braid density, a reduced durometer, and / or a reduced wall thickness as compared to other sections of the shaft 110.
[0036]
[0062] Additionally, the conduit 102 / scaffold 106 may include a central region 120 that is more flexible than the proximal 118 and distal 122 regions of the conduit. The scaffold pattern / design is optimized to provide the central region 120 with more flexibility and reduced stiffness relative to the remainder of the scaffold. For example, the central region 120 may include a section of helically wound scaffold elements with an optimized pitch and reduced element width to promote flexibility and bending in response to the anatomy while resisting kinking or folding of the conduit.
[0037]
[0063] Additionally, the distal tip 116 may include a distal tip section 113 that is also highly flexible / soft. Increased flexibility of the distal tip section 113 may be achieved by a reduced durometer section and / or reduced wall thickness. The length of the distal tip 116 is configured to allow the blood pump to "dock" or rest within the ventricular apex to reduce motion of the overall assembly during use. The flexible distal tip section 113 allows for flexion and accommodation of cardiac contractions, pump motion, and various anatomical structures. Additionally, the distal tip section 113 may include various wall thicknesses and durometers to optimize flexion and distribute loads to other sections of the blood pump 100 (e.g., to the central region 120 or distal shaft portion 111).
[0038]
[0064] While FIG. 1A and above describe sections of the blood pump 100 having increased flexibility or reduced stiffness relative to other sections of the blood pump, FIG. 1B illustrates an outlet section 115 and an inlet section 117 of the blower pump 100 having increased stiffness or reduced flexibility relative to other sections of the blood pump. The outlet section 115 may generally include a proximal portion 118 of the conduit, the impeller 104, the proximal struts 112a, and the hub 114a. The inlet section 117 may generally include a distal portion 122 of the conduit, the distal struts 112b, and the hub 114b. In general, the outlet section 115 and the inlet section 117 are stiffer than the distal shaft portion 111 of the shaft 110, the central region 120 of the conduit 102, and the distal tip section 113 of the distal tip 116.
[0039]
[0065] 1A and 1B show regions of the blood pump with increased flexibility and regions of the pump with increased stiffness. Collectively, these regions of stiffness and flexibility are designed and arranged to provide stiffness in regions that promote concentricity of the impeller within the scaffold while allowing flexibility in regions that must contact tissue or bend around anatomical structures. Generally, the inlet and outlet regions of the blood pump are relatively stiff compared to the central region of the scaffold, the distal tip, and the catheter shaft, which are relatively flexible. This allows loads applied to the distal tip (e.g., contacting the heart wall with the distal tip) to be transferred from the distal tip to the center of the scaffold (central region 120) to prevent the pump hub or inlet region from bending. Thus, the central region is designed and configured to always collapse first when a lateral load is applied to the blood pump or scaffold (e.g., contacting an anatomical structure). In the inlet and outlet regions, the struts may have increased width near the attachment to the hub (e.g., hubs 114a and 114b) to increase the stiffness of the scaffold in these regions. The outlet region includes rigid radial and axial elements and rigid supports in the impeller bearing assembly so that the cantilevered impeller and impeller shaft design promotes impeller and scaffold concentricity and maintains proper tip clearance. Similarly, the inlet region may include increased width of the distal elements to maintain the inlet and prevent folding. The stiffness in the distal inlet region allows any potential forces from the distal tip to be transferred to the central portion of the scaffold (and not to the inlet region). The central region accommodates compound bending and pumping motions while minimizing deflection relative to the outlet region in the proximal portion of the scaffold.
[0040]
[0066] FIG. 2 shows a close-up view of the distal shaft portion 111 of the catheter 110, including the connection to the hub 114a. FIG. 2 includes illustrations of features that allow the distal shaft portion 111 to be flexible relative to other sections of the shaft. The catheter shaft 110 is coupled to the blood pump hub 114a and extends proximally from the hub 114a to a handle and / or console that controls the operation of the system. When the blood pump is inserted inside the patient's heart, the shaft 110 extends proximally away from the pump and outside the patient's body. In some embodiments, the catheter distal shaft portion 111 is the most flexible section of the catheter 110. Such increased flexibility relative to the remainder of the catheter may be achieved, for example, by a reduced braid density, a reduced durometer, and / or a reduced wall thickness. This flexible distal shaft portion 111 is designed and configured such that its features are anatomically aligned with the aortic arch and the descending aorta when the blood pump is inserted into the patient's heart. In some embodiments, the distal shaft portion 111 can have a length D, which can be, for example, up to 5 inches in length. The distal shaft portion 111 can have increased flexibility or reduced stiffness at this length D relative to the remainder of the shaft 110. This results in reduced pressure on the leaflets and ventricular walls. The reduced external force on the pump (pressure on the ventricular walls and valve) helps maintain concentricity between the pump and the scaffold. Additionally, the reduced pressure on the ventricular walls helps maintain tip clearance (i.e., distance between the impeller and the scaffold / blood conduit), reducing anatomical damage to the heart and surrounding anatomy.
[0041]
[0067] FIG. 3 shows additional views of the blood conduit 102 of the blood pump 100, including the scaffold 106, membrane 108, proximal struts 112a, first opening (outlet) 101, distal struts 112b, and second opening (inlet) 103. The blood conduit and / or scaffold of the blood pump may include features or design elements configured to maintain a tip gap between the impeller and the scaffold / membrane during use. As previously described, the conduit 102 may include a proximal region 118, a central region 120, and a distal region 122. The blood conduit 102 of the pump is designed with specific features configured to maintain a tip gap between the impeller and the scaffold / membrane in various anatomical structures. This includes design elements that allow designated areas or portions of the blood conduit to be flexible while other designated areas or portions of the blood conduit are rigid.
[0042]
[0068] For example, the proximal portion 118 of the scaffold may include an area of increased element density 119 to increase stiffness around the impeller and outlet region. The area of increased element density 119 may include a plurality of axial elements 121 connected to a plurality of radial elements 123. In some embodiments, the radial elements may be arranged in a chevron pattern or arrangement of diagonal (i.e., diagonal) elements. In the illustrated embodiment, the axial element 121 is positioned between two areas of radial elements 123. In some embodiments, the radial and axial elements in area 119 may have an increased width relative to other elements in the scaffold (e.g., the helical elements in the central region 120) to provide increased stiffness in area 119. Additionally, as shown in FIG. 3, the proximal strut 112a may have a tapered leg design with a wider base that is optimized for stiffness in the outlet region of the blood pump.
[0043]
[0069] The distal portion 122 of the scaffold may also include a region 125 of increased element density to increase stiffness around the inlet region. Like the proximal portion, the distal portion may include a plurality of axial elements 127. Region 125 may include elements having an increased width relative to other elements in the scaffold (e.g., helical elements in the central region 120) to provide increased stiffness in region 125. Additionally, the distal struts 112b may have a tapered leg design with a wider base that is optimized for stiffness in the inlet region of the blood pump.
[0044]
[0070] As further shown in FIG. 3, the central portion 120 may include a plurality of helical elements 129 having a pitch and width optimized to promote bending in the central portion without twisting. The central portion 120 must be sufficiently flexible so as to be softer than the anatomical structures in which it is positioned. Allowing it to bend without twisting allows flow performance to be maintained in a variety of operating conditions. Thus, adapting to the anatomical structures does not sacrifice flow performance. In some embodiments, the helical elements 129 have a width that is less than the width of the elements in section 119 of the proximal portion 118 and section 125 of the distal portion 122.
[0045]
[0071] In some embodiments, the scaffold 106 shown in FIG. 3 may be generally divided into five different regions: 1) central portion 122, 2) region 125, 3) region 119, 4) distal strut region 112b, 5) proximal strut region 112a. As explained above, the scaffold may include a central portion 122 that may include flexible helical elements designed to bend without twisting or folding, allowing flow performance to be maintained in various operating conditions. Adapting to the anatomical structure does not sacrifice flow performance. The central region must be flexible enough so that when the blood pump contacts the anatomical structure, the central region is softer than the anatomical structure and collapses. The scaffold further includes stiffer regions 119 (around the impeller 104) and 125 (towards the inlet region). Furthermore, the regions around the proximal and distal struts (inflow and outflow regions) are also relatively stiff. In combination with sections 119 and 125, the sections on the proximal and distal ends of the scaffold act as relatively stiff beams, especially compared to the flexible central section, which therefore always collapses or bends first when a lateral load is applied to the scaffold (e.g., contact with an anatomical structure).
[0046]
[0072] FIG. 4 is a close-up view of the outlet section 115 of the blood pump including features that provide increased stiffness. In this view, the impeller 104 is shown supported by an impeller shaft 131 that extends through an impeller bearing assembly 133 positioned within the hub 114a and terminates at the distal end of the impeller (optionally just distal to the impeller blades). In general, the structures illustrated in FIG. 4 within the proximal portion of the blood conduit may be collectively referred to as an impeller assembly. The impeller assembly may include, for example, the impeller shaft, the impeller, or any distal cap or hub on the distal end of the impeller shaft, and any structure that couples or encapsulates the proximal portion of the impeller shaft to the impeller bearing assembly. In some embodiments, the distal impeller hub 107 may seal, encapsulate, or cover the impeller shaft and / or the impeller blades. Although the distal impeller hub is shown as a separate element in FIG. 4, it should be understood that in some embodiments, the distal impeller hub is not present or optionally the distal impeller hub is integral with the impeller shaft. The distal end of the impeller is not supported by any other features or elements and is not connected to the scaffold or to the distal end of the blood pump or conduit. There are no structures located within the scaffold 106 distal to the impeller assembly (e.g., the impeller, impeller shaft, and optionally the distal impeller hub). In fact, in the embodiment of FIG. 4, the impeller assembly is the only structure located within the blood conduit of the blood pump. The impeller 104 and impeller shaft 131 are arranged in a cantilever design configuration with the distal end of the impeller assembly freely positioned within the scaffold. The position of the impeller relative to the scaffold is maintained by structures within the outlet area of the blood pump and / or the configuration of the impeller and scaffold themselves. No distal bearing is required or used. The stiffness of the impeller shaft 131 and its passage through the stiff impeller bearing assembly 133 provides the stiffness needed to maintain the impeller position and tip clearance within the scaffold and blood conduit during operation in a variety of conditions.The overall design, including stiffness around the impeller, provides a "quiet" area around the impeller to allow tip clearance to be maintained while providing flexibility on either side of the impeller (e.g., in the catheter shaft and in the central portion of the scaffold). Preventing or limiting flexing around the impeller and impeller shaft means that the concentricity of the impeller, and ultimately the tip clearance between the impeller and the scaffold, is maintained. It is further noted that in some embodiments, the proximal struts 112a may be inserted into and supported by the impeller bearing assembly 133 in area 135. The supported struts 112a add stiffness to the exit area 115.
[0047]
[0073] A drive cable 137 extends through the shaft and is coupled to the impeller shaft 131. The drive cable may be rotated by a motor (not shown) to provide rotation to the impeller. The drive cable may be sufficiently flexible to allow for flexibility in the distal shaft portion 111 described above. Attachment of the drive cable to the impeller shaft allows for increased stiffness through the hub 114a, impeller bearing assembly 133, and impeller 104.
[0048]
[0074] FIG. 5 illustrates a close-up view of the distal hub 114b. In this embodiment, the struts may be overmolded into the hub itself. In this view, it can be seen how the distal end 134 of the strut 112b extends past the arms 136 of the hub and into the hub body itself. Extending the struts into the hub body may increase the stiffness of the hub (and thus the inlet area) and prevent buckling or bending at the strut / arm transition when large forces are applied to the blood pump (e.g., at the distal tip). The distal end 134 of the strut may further include a slit or piercing element 138. The slit or piercing element 138 allows for the inflow of polymer material(s) during injection molding of the hub to ensure a strong bond between the strut and the hub and to prevent the strut from pulling out of the hub.
[0049]
[0075] FIG. 6 shows a cross-sectional view of the inlet section 117 and its connection to the distal tip 116, which includes the flexible distal tip section 113. As explained above, the flexible distal tip section 113 can be configured and designed to have increased flexibility by adjusting or altering the wall thickness within the tip. The distal tip 116 can include a guidewire lumen 140 extending from the inlet section through the distal tip. The guidewire lumen can be configured to accommodate and receive a guidewire during positioning of the blood pump within the anatomy. As shown in FIG. 6, the guidewire lumen can include a junction 142 either within the hub 114b or at the transition from the hub to the distal tip section 113, where the diameter of the guidewire lumen changes. As shown, the diameter of the guidewire lumen within the hub 114b is smaller than the diameter of the guidewire lumen within the distal tip section 113. In the illustrated embodiment, the diameter of the guidewire lumen transitions from a first (smaller) diameter at the hub to a second (larger) diameter at the distal tip section. This results in a larger wall thickness at the hub resulting in more stiffness at the hub compared to a smaller wall thickness at the distal tip resulting in less stiffness at the distal tip. In addition to using wall thickness to make the distal tip more flexible, the distal tip 116 may also include a reduced durometer material in the distal tip section 113 to increase flexibility.
[0050]
[0076] FIG. 7 shows a close-up view of the proximal portion 118 of the conduit 102, including the impeller 104, the scaffold 106, the membrane 108, the proximal struts 112a, and the proximal hub 114a. In some cases, the impeller 104 is positioned completely axially within the conduit 102. In other cases, as shown in FIG. 2, the proximal portion of the impeller 104 is positioned at least partially outside the conduit 102. That is, at least a portion of the impeller may extend proximally beyond the proximal end of the conduit. As shown in FIG. 7, a portion of the impeller 104 can be seen to extend beyond the membrane / conduit and into the first opening 101 (e.g., into the outlet). When the impeller extends proximally past the proximal end of the conduit, the moment arm formed by the impeller and the impeller shaft is reduced.
[0051]
[0077] It is important to maintain a minimum distance between the rotating impeller 104 and the inner surface of the blood conduit 102 so that the impeller blades do not contact the inner surface of the blood conduit while they are rotating. As shown in FIG. 8A, when the blood conduit extends in a straight line, the longitudinal axis of the impeller is centered on the longitudinal axis of the blood conduit, and the gap between the rotating impeller blades and the inner surface of the blood conduit remains substantially constant. When the blood conduit is disposed in a position that requires it to bend (such as when the blood pump extends from the left ventricle through the aortic valve into the ascending aorta), the inner surface of the blood conduit may move closer to one side of the distal portion of the impeller, as shown in FIG. 8B. The collective features described herein and above enable the blood pump of the present disclosure to maintain a uniform tip gap when a load is applied to the pump, causing bending or deformation in various areas of the pump. As described above, selective bending and flexibility at the distal tip, central portion of the scaffold, and distal shaft portion of the shaft, combined with stiffness at the inlet and outlet regions of the blood pump, allows the cantilevered impeller to maintain tip clearance within the blood conduit.
[0052]
[0078] 9 shows one embodiment in which the membrane 108 and scaffold 106 are illustrated in phantom so that the impeller 104 is visible. In this example, the impeller 104 tapers from its proximal portion 200 towards its distal portion 204, i.e., the diameter of the impeller blades decreases from the proximal portion 200 of the impeller 104, through the central portion 202 and the distal portion 204 towards the distal end 206 of the impeller 104. Meanwhile, the diameter of the blood conduit 102 remains substantially constant. The gap between the impeller blade tips and the blood conduit 102 thus increases from the proximal portion 200 of the impeller towards the distal end 206 of the impeller. In one embodiment, the impeller 104 may taper or reduce in diameter only in the distal portion 204 of the impeller (i.e., the impeller blade diameter is relatively constant in the proximal and central portions 200 and 202. In some embodiments, the tapered sections may have different taper angles.
[0053]
[0079] It should be understood that any feature described herein with respect to one embodiment may be replaced by or combined with any feature described with respect to another embodiment.
[0054]
[0080] When a feature or element is referred to herein as being "on" another feature or element, it may be directly on the other feature or element, or intervening features and / or elements may also be present. In contrast, when a feature or element is referred to as being "directly on" another feature or element, there are no intervening features or elements. When a feature or element is referred to as being "connected," "mounted," or "coupled" to another feature or element, it should also be understood that it is directly connected, mounted, or coupled to the other feature or element, or intervening features or elements may be present. In contrast, when a feature or element is referred to as being "directly connected," "directly mounted," or "directly coupled" to another feature or element, there are no intervening features or elements. Although described or illustrated with respect to one embodiment, a feature or element so described or illustrated may apply to other embodiments. It will also be understood by those skilled in the art that a reference to a structure or feature disposed "adjacent" another feature may have portions that overlap or underlie the adjacent feature.
[0055]
[0081] The terms used herein are for the purpose of describing particular embodiments only and are not intended to be limiting of the present invention. For example, as used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It is further understood that the terms "comprises" and / or "comprising", as used herein, specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items and may be abbreviated as " / ".
[0056]
[0082] Spatially related terms such as "under," "below," "lower," "over," "upper," and the like may be used herein for ease of description to describe the relationship of one element or feature to another element(s) or feature(s) as illustrated in the figures. It should be understood that the spatially related terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is inverted, an element described as "under" or "beneath" the other element or feature would be oriented "over" the other element or feature. Thus, the exemplary term "under" can encompass both an upper and lower orientation. The device may be otherwise oriented (rotated 90 degrees or in other orientations) and the spatially related descriptors used herein interpreted accordingly. Similarly, the terms "upward," "downward," "vertical," "horizontal," and the like are used herein for descriptive purposes only, unless specifically indicated otherwise.
[0057]
[0083] The terms "first" and "second" may be used herein to describe various features / elements (including steps), but these features / elements should not be limited by these terms unless the context indicates otherwise. These terms may be used to distinguish one feature / element from another. Thus, a first feature / element discussed below may be referred to as a second feature / element, and similarly, a second feature / element discussed below may be referred to as a first feature / element, without departing from the teachings of the present disclosure.
[0058]
[0084] Throughout this specification and the claims that follow, unless the context requires otherwise, the word "comprise," and variations such as "comprises" and "comprising," mean that various components may be used jointly in methods and articles (e.g., compositions and apparatuses, including devices and methods). For example, it should be understood that the term "comprising" implies the inclusion of any described elements or steps, but not the exclusion of other elements or steps.
[0059]
[0085] As used in this application within the specification and claims, including as used in the examples, unless expressly specified otherwise, all numbers may be read as if they were preceded by the word "about" or "approximately", even if the term does not explicitly appear. The term "about" or "approximately" may be used when describing a magnitude and / or location to indicate that the described value and / or location is within a reasonably expected range of values and / or locations. For example, a numerical value may have a value that is + / -0.1% of the stated value (or range of values), + / -1% of the stated value (or range of values), + / -2% of the stated value (or range of values), + / -5% of the stated value (or range of values), + / -10% of the stated value (or range of values), etc. Any numerical value provided herein should also be understood to include about or approximately that value, unless the context indicates otherwise. For example, if the value "10" is disclosed, then "about 10" is also disclosed. Any numerical ranges recited herein are intended to include all subranges subsumed therein. It is also to be understood that when a value is disclosed, "less than or equal to" that value, "more than or equal to" that value, and possible ranges between the values are also disclosed, as would be well understood by one of ordinary skill in the art. For example, when a value "X" is disclosed, "less than or equal to X" as well as "more than or equal to X" (e.g., where X is a number) are also disclosed. It is also to be understood that throughout this application, data is provided in several different formats, and furthermore, this data represents end and starting points, as well as ranges for any combination of the data points. For example, when a specific data point "10" and a specific data point "15" are disclosed, it is to be understood that greater than 10 and 15, greater than or equal to 10 and 15, less than 10 and 15, less than or equal to 10 and 15, and equal to 10 and 15 are also disclosed, as well as 10 to 15. It is also to be understood that each singular between two specific singulars is also disclosed. For example, when 10 and 15 are disclosed, 11, 12, 13, and 14 are also disclosed.
[0060]
[0086] While preferred embodiments of the present invention have been shown and described herein, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, modifications, and substitutions will now occur to those skilled in the art without departing from the invention. It will be understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention. It is intended that the following claims define the scope of the invention, and that methods and structures within the scope of these claims and their equivalents are thereby covered.
Claims
1. a blood conduit supported by a catheter, the blood conduit comprising an expandable scaffold and an impermeable membrane disposed over a portion of the expandable scaffold; an impeller assembly rotatably supported within a proximal portion of the blood conduit; Equipped with The expandable catheter blood pump, wherein the impeller assembly is the only structure positioned within the blood conduit.
2. The blood pump of claim 1 , wherein the impeller assembly includes one or more impeller blades coupled to an impeller shaft.
3. The blood pump of claim 2 , wherein the impeller shaft passes through an impeller bearing assembly proximate to the one or more impeller blades.
4. The blood pump of claim 3 , wherein the impeller bearing assembly is positioned at least partially within a proximal hub of the blood pump.
5. The blood pump of claim 4 , further comprising a flexible drive cable coupled to a proximal end of the impeller shaft.
6. The blood pump of claim 5 , wherein the impeller shaft is stiffer than the flexible drive cable.
7. The blood pump of claim 1 , wherein the impeller assembly is cantilevered.
8. The blood pump of claim 1 , wherein there are no structures located within the blood conduit distal to the impeller assembly.
9. The blood pump of claim 1 , wherein the blood conduit comprises an open lumen distal to the impeller assembly.
10. The blood pump of claim 1 , wherein there is no bearing located distally of the impeller assembly.
11. The blood pump of claim 1 , wherein the impeller assembly is disposed within an outlet region of the expandable scaffold.
12. The blood pump of claim 11 , wherein the outlet section includes a plurality of proximal struts forming at least one opening.
13. The blood pump of claim 12 , wherein the at least one opening is located proximal to a proximal end of the impermeable membrane.
14. The blood pump of claim 12 , wherein the impeller assembly is at least partially disposed within the outlet section.
15. The blood pump of claim 11 , wherein the expandable section further comprises a central portion distal to the impeller assembly.
16. The blood pump of claim 15, wherein the central portion is more flexible than the outlet section.
17. The blood pump of claim 11 , wherein the catheter further comprises a distal shaft section coupled to the outlet section.
18. The blood pump of claim 17 , wherein the distal shaft section is more flexible than the outlet section.
19. A blood conduit supported by a catheter, the blood conduit comprising an expandable scaffold and an impermeable membrane disposed over the expandable scaffold, the expandable scaffold comprising: a) a plurality of distal struts forming an entrance region; b) a distal shroud section; c) central shroud area; d) a proximal shroud section; and e) Five separate sections, including a plurality of proximal struts forming an exit section. a blood conduit comprising: an impeller disposed within the proximal shroud section and rotatably supported by a drive cable assembly that extends through the catheter, through the exit section, and into the proximal shroud section, the drive cable assembly being more flexible proximal of the exit section than it is through the exit section and the proximal shroud section; 1. An expandable catheter blood pump comprising:
20. 20. The blood pump of claim 19, wherein the drive cable assembly does not extend distally into the central shroud section.
21. 20. The blood pump of claim 19, wherein the impeller and the drive cable assembly are not positioned in the central shroud section, the distal shroud section, or the inlet section.
22. 20. The blood pump of claim 19, wherein the drive cable assembly comprises a flexible drive cable coupled to a rigid impeller shaft.
23. 23. The blood pump of claim 22, wherein the flexible drive cable is coupled to the rigid impeller shaft proximate an impeller bearing assembly.
24. 23. The blood pump of claim 22, wherein the flexible drive cable is more flexible than the rigid impeller shaft.
25. 20. The blood pump of claim 19, wherein the drive cable assembly and the impeller are cantilevered.
26. 20. The blood pump of claim 19, wherein there are no structures located within the blood conduit other than the impeller and the drive cable assembly.
27. A catheter shaft; a proximal hub assembly coupled to the catheter shaft; a blood conduit supported by the proximal hub, the blood conduit comprising an expandable scaffold and an impermeable membrane disposed on the expandable scaffold, the expandable scaffold comprising an inlet region, a central region, and an outlet region; a cantilevered impeller assembly disposed at least partially within the outlet section, the cantilevered impeller assembly including a drive assembly extending through the catheter shaft and the impeller assembly; a distal tip coupled to the inlet section; and Equipped with An expandable catheter blood pump, wherein the distal tip, the central section, and the catheter shaft are more flexible than the inlet section and the outlet section, and the blood pump is configured to bend within the distal tip, the central section, and / or the catheter shaft in response to a force applied to the blood pump.
28. 28. The blood pump of claim 27, wherein the outlet section and the drive assembly are sufficiently rigid to maintain a tip gap between the impeller assembly and the blood conduit when a force is applied to the blood pump.
29. 28. The blood pump of claim 27, wherein the drive assembly is more flexible within the catheter shaft than it is within the outlet section.
30. 30. The blood pump of claim 29, wherein the drive assembly comprises a flexible drive cable within the catheter shaft and an impeller shaft within the outlet section.
31. 31. The blood pump of claim 30, wherein the impeller shaft passes through an impeller bearing assembly.
32. 28. The blood pump of claim 27, wherein the drive assembly does not extend distally into the central section.
33. 28. The blood pump of claim 27, wherein the impeller assembly and the drive assembly are not located in the central section or the inlet section.
34. a blood conduit supported by a catheter, the blood conduit comprising an expandable scaffold and an impermeable membrane, the blood conduit having a substantially constant diameter; an impeller rotatably supported within a proximal portion of the blood conduit, the impeller having a diameter that decreases from a proximal end of the impeller to a distal portion of the impeller; Equipped with A catheter blood pump, wherein the blood pump is configured to rotate the impeller within the blood conduit to pump blood from a blood pump input to a blood pump outlet.