Distal outflow cage of blood pump

Abstract

The invention relates to a blood pump distal outflow cage. A blood pump assembly with a blood outflow cage component is designed to reduce pressure on a patient's vasculature, reduce hemolysis and damage to blood, and improve manufacturability. The blood pump assembly includes a blood outflow cage designed to expel blood from a distal end of the blood pump assembly. The opening in the blood outflow cage has rounded edges, corners, and junctions and smoothly transitions into the diffuser at the proximal end of the blood outflow cage. When the column of the blood outflow cage transitions into a thinner cylindrical section at the proximal end of the blood outflow cage, its thickness may further taper.

Description

[0001] This application is a divisional application. The filing date of the original application is December 21, 2020, the application number is 202080091784.7, and the invention title is "Blood Pump Distal Outflow Cage"

[0002] Cross - Reference to Related Applications

[0003] This application claims the benefit of priority to U.S. Provisional Application No. 62 / 955,603, filed on December 31, 2019, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0004] The present disclosure relates to a blood pump assembly. More specifically, the present disclosure relates to an outflow cage component disposed at the distal end of a blood pump assembly. Background Art

[0005] Blood pump assemblies, such as intracardiac blood pump assemblies, are introduced into the heart to deliver blood from the heart into the arteries. For example, when used for right - heart support, a blood pump assembly can draw blood from the inferior vena cava and discharge the blood into the pulmonary artery. In some cases, a blood pump assembly can be inserted through the femoral vein via a catheterization procedure, into the inferior vena cava, through the right atrium, across the tricuspid valve, into the right ventricle, through the pulmonary valve, and then into the pulmonary artery. This insertion path is tortuous and requires the blood pump assembly to pass through several bends, which can introduce pressure on the patient's vasculature, especially in cases of contact with the distal end of the blood pump assembly. Additionally, when pumping blood through the blood pump assembly, pumping blood through the blood pump assembly can damage the blood or cause hemolysis. Finally, since the blood outflow cage described herein incorporates a diffuser at its distal end, the junction between the struts of the blood outflow cage and the diffuser can further interfere with blood flow and also complicate manufacturing. Summary of the Invention

[0006] The devices, manufacturing methods, and embodiments described herein provide a blood pump assembly having an outflow cage member that is designed to reduce pressure on a patient's vasculature, reduce hemolysis and damage to blood, and improve manufacturability. The blood pump assembly includes a blood outflow cage that is designed to discharge blood from the distal end of the blood pump assembly. The blood outflow cage has rounded edges, corners, and junctions. This provides several benefits. Rounding the outer edge of the blood outflow cage reduces pressure and abrasion on the vasculature as the blood pump assembly is inserted into the patient's body and advanced to its operative position. As described in U.S. Patent No. 9,433,713, which is incorporated herein by reference, rounding both the inner and outer edges of the blood outflow cage also results in a significant reduction in hemolysis. Additionally, since the blood outflow cage described herein incorporates a diffuser at its distal end, using internal fillets (i.e., the corners where the struts intersect the diffuser) at the junctions between the struts and the diffuser further improves blood flow around these junctions. This also results in fewer red blood cell ruptures as blood flows through the blood outflow cage, thereby further reducing hemolysis. Finally, the rounded edges, rounded corners, and rounded junctions of the blood outflow cage described herein improve the manufacturability of the blood outflow cage. Specifically, these features facilitate manufacturing using automated machining processes and allow the entire blood outflow cage to be formed from a single workpiece.

[0007] In one aspect, the present disclosure describes a blood outflow cage for use in an intravascular blood pump assembly and sized to pass through a patient's vascular lumen. The assembly includes a distal cap having an outer surface that is substantially conical, substantially curved conical, or substantially dome-shaped; a diffuser having an outer surface that is substantially conical or substantially curved conical. The diffuser is disposed proximal to the distal cap. The assembly has a peripheral wall having: an inner surface; an outer surface; two or more blood discharge openings, each blood discharge opening defined by two struts, wherein each strut has a rounded inner edge and outer edge and a rounded junction with the diffuser. The proximal end of each blood discharge opening has a rounded corner and a first cylindrical section adjacent to the proximal end of each strut. The blood outflow cage optionally has a hole passing through the diffuser and the distal cap. In some aspects, the thickness of the peripheral wall tapers from a first thickness at the struts to a second thickness at the first cylindrical section, wherein the first thickness is greater than the second thickness. In some aspects, the peripheral wall further has a second cylindrical section adjacent to the first cylindrical section, and wherein the outer diameter of the second cylindrical section is less than the outer diameter of the first cylindrical section. The blood outflow cage optionally has a flexible tubular extension coupled to the distal cap. In some aspects, the distal end of the flexible tubular extension is curved in its relaxed state. The blood outflow cage optionally has an inner rounded corner between the inner surface of each strut and the diffuser. In some aspects, the inner rounded corner has a radius of about 0.30 mm. In some aspects, the inner edges of the struts of the blood outflow cage each have a first radius between 0.07 mm and 0.21 mm, and the outer edges of the struts of the blood outflow cage each have a second radius between 0.07 mm and 0.21 mm. In some aspects, the blood outflow cage is made of a single piece of metal or polymer.

[0008] In another aspect, the present disclosure describes a blood pump assembly sized to pass through a patient's vascular lumen. The blood pump assembly includes: a pump; an impeller blade rotatably coupled to the pump; a blood inflow cage extending about an axis of rotation of the impeller blade and having at least two blood inlet openings; a cannula in fluid communication with a first housing, the proximal end of the cannula being coupled to the blood inflow cage; and a blood outflow cage coupled to the distal end of the cannula. The blood outflow cage includes a distal cap having an outer surface that is substantially conical, substantially curved conical, or substantially dome-shaped; a diffuser having an outer surface that is substantially conical or substantially curved conical, wherein the diffuser is disposed proximal to the distal cap; and a peripheral wall having: an inner surface; an outer surface; two or more blood discharge openings, each blood discharge opening being defined by two struts, wherein each strut has a rounded inner edge and an outer edge and a rounded junction with the diffuser, and wherein the proximal end of each blood discharge opening has a rounded corner; and a first cylindrical section adjacent to the proximal end of each strut. The blood pump assembly optionally includes a hole passing through the diffuser and the distal cap of the blood outflow cage. In some aspects, the thickness of the peripheral wall of the blood outflow cage tapers from a first thickness at the struts to a second thickness at the first cylindrical section, wherein the first thickness is greater than the second thickness. In some aspects, the peripheral wall of the blood outflow cage has a second cylindrical section adjacent to the first cylindrical section, wherein the outer diameter of the second cylindrical section is less than the outer diameter of the first cylindrical section. The blood pump assembly optionally includes a flexible tubular extension coupled to the distal cap of the blood outflow cage. In some aspects, the distal end of the flexible tubular extension is curved in its relaxed state. The blood pump assembly may further include an inner rounded corner between the inner surface of each strut and the diffuser of the blood outflow cage. In some aspects, the inner rounded corner has a radius of about 0.30 mm. In some aspects, the inner edges of the struts of the blood outflow cage each have a first radius between 0.07 mm and 0.21 mm, and the outer edges of the struts of the blood outflow cage each have a second radius between 0.07 mm and 0.21 mm. In some aspects, the blood outflow cage is made of a single piece of metal or polymer. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 A blood pump assembly according to aspects of the present disclosure is shown.

[0010] Figure 2 A perspective view of a blood outflow cage according to aspects of the present disclosure is shown.

[0011] Figure 3 A perspective view of a blood outflow cage according to aspects of the present disclosure is shown.

[0012] Figure 4 A cross-sectional view of a blood outflow cage according to aspects of the present disclosure is shown.

[0013] Figure 5A and Figure 5B shows an isometric view of a blood outflow cage in accordance with aspects of the present disclosure.

[0014] Figure 6 shows a cross-sectional view of a blood outflow cage in accordance with aspects of the present disclosure. DETAILED DESCRIPTION

[0015] The present technology will now be described with reference to the following exemplary systems and methods.

[0016] Figure 1 An exemplary blood pump assembly 100 suitable for right heart support is depicted. The blood pump assembly 100 includes a catheter 102, a blood pump 104, a blood inflow cage 106, a cannula 108, a blood outflow cage 110, and a pigtail extension 112. The blood pump 104 is coupled to the proximal end of the cannula 108 via the blood inflow cage 106. In some cases, the blood inflow cage 106 may encapsulate some or all of the blood pump 104 and / or may be integrated into the housing of the blood pump 104. The distal end of the cannula 108 is further coupled to the blood outflow cage 110. The pigtail extension 112 is coupled to the distal end of the blood outflow cage 110. The catheter 102 is also coupled to the proximal end of the blood pump 104.

[0017] The blood pump 104 includes a rotatable impeller blade (not shown), which may be driven by an internal motor. For example, the blood pump 104 may include an internal electrical micro-axial pump having a pumping capacity greater than 4 L / min and a diameter of 21 or 22 Fr. The blood pump 104 may also be driven by a remote source, such as a motor located outside the patient and coupled to a flexible drive shaft passing through the catheter 102.

[0018] The catheter 102 may house wires that couple the motor of the blood pump 104 to one or more electrical controllers or other sensors. The catheter 102 may also house other components, such as a cleaning fluid conduit, and / or other conduits configured to receive a guide wire.

[0019] The blood inflow cage 106 includes one or more holes or openings configured to allow blood to be drawn into the cannula 108 when the blood pump 104 is operating.

[0020] The cannula 108 may include an elongate flexible hose portion. For example, the cannula 108 may be at least partially composed of a polyurethane material. The cannula 108 may further include a shape memory coil such as a nitinol coil. The cannula 108 may be formed such that it includes one or more bends or curves in its relaxed state, or it may be configured to be straight in its relaxed state. The cannula 108 may be of any suitable diameter, but will generally be similar to the diameter of the blood pump 104.

[0021] The blood outflow cage 110 includes one or more holes or openings that are configured to allow blood to flow out of the cannula 108 and out of the blood pump assembly 100. The blood outflow cage 110 may be composed of any suitable biocompatible material. For example, the blood outflow cage 110 may be formed from a biocompatible metal such as stainless steel, titanium, or a biocompatible polymer such as polyurethane. Additionally, the surface of the blood outflow cage 110 may be treated in various ways, including but not limited to etching, texturing, or coating or plating with another material. For example, the surface of the blood outflow cage 110 may be laser textured. Although the blood outflow cage 110 may be manufactured from multiple pieces, the designs described in more detail below facilitate manufacturing the blood outflow cage from a single piece of metal or polymer, for example, by using an automated machining process. The blood outflow cage 110 may also be manufactured using rapid prototyping or injection molding processes. Other features of the blood outflow cage 110 will be described in detail below with respect to Figures 2 to 6 the examples of

[0022] The pigtail extension 112 assists in stabilizing and positioning the blood pump assembly 100 in the correct position in the pulmonary artery. The pigtail extension 112 may be solid or tubular. If tubular, the pigtail extension 112 may be configured to allow a guide wire to pass through it to further assist in positioning the blood pump assembly 100. The pigtail extension 112 may be of any suitable size. For example, the outer diameter of the pigtail extension may be in the range of 4 - 8 Fr. The pigtail extension 112 may be at least partially composed of a flexible material and may be configured from a straight configuration to a partially curved configuration. The pigtail extension 112 may also have sections of different stiffness. For example, the pigtail extension 112 may include: a proximal section that is stiff enough to prevent it from buckling, thereby holding the blood outflow cage 110 in the desired position; and a distal section that is softer and has a lower stiffness, thereby providing a non - traumatic tip for contacting the pulmonary artery wall and allowing a guide wire to be loaded. In this case, the proximal and distal sections of the pigtail extension 112 may be composed of different materials, or may be composed of the same material that has been treated to provide different stiffnesses.

[0023] However, the pigtail extension 112 is an optional structure. The present technique can also be used with blood pump assemblies that include extensions of different types, shapes, materials, and qualities. Similarly, the present technique can be used with blood pump assemblies that do not have any type of extension beyond the distal end of the blood outflow cage 110.

[0024] The blood pump assembly 100 can be percutaneously inserted. For example, when used for right heart support, the blood pump assembly 100 can be inserted via a catheterization procedure through the femoral vein, into the inferior vena cava, through the right atrium, across the tricuspid valve, into the right ventricle, through the pulmonary valve, and then into the pulmonary artery. After being positioned in this manner, the blood pump assembly 100 delivers blood from the blood inflow cage 106 located inside the inferior vena cava through the cannula 108 to the blood outflow cage 110 located inside the pulmonary artery.

[0025] Figures 2 - 6 An exemplary blood outflow cage 110 in accordance with aspects of the present technique is depicted. Figure 2 、 Figure 3 、 Figure 4 、 Figure 5A 、 Figure 5B 、and Figure 6 All reference numerals shared between

[0026] Figure 2 A perspective view of the blood outflow cage 110 is depicted. The distal end of the blood outflow cage 110 includes a diffuser 212 that transitions into a rounded end cap 214. At its proximal end, the blood outflow cage 110 consists of a peripheral wall having an inner surface and an outer surface, a cylindrical section 200, another cylindrical section 201, and five struts 202, 204, 206, 208, and 210. The cylindrical section 200 is adapted to be coupled to the cannula 108, and the diameter of the cylindrical section 201 is slightly larger than the diameter of the cylindrical section 200. The distal end of the cylindrical section 201 transitions into the five struts 202, 204, 206, 208, and 210, which define five openings through which blood can leave the blood outflow cage 110. Although Figure 2 the exemplary blood outflow cage 110 is shown having five struts, any number of two or more struts can be used. The struts 202, 204, 206, 208, and 210 are connected to the distal end of the diffuser 212.

[0027] The diffuser 212 is adapted to direct blood out of the blood outflow cage 110. Thus, although the diffuser 212 has a curved conical shape in Figures 2 to 6 the example of Figures 2 to 6The diffuser 212 shown in FIG. 1 has a smooth surface, but it may include vanes, fins, or other features suitable for further assisting blood flow out of the blood outflow cage 110. Finally, although in Figures 2 to 6 The diffuser 212 shown in FIG. 1 has a blunt proximal tip but has no holes (eg, Figure 4 In an alternative embodiment of the distal end of the blood outflow cage 110 through which the hole 410 is passed, it may optionally be pointed.

[0028] End cap 214 is depicted as having a dome shape. However, end cap 214 may have any shape that facilitates insertion of blood pump assembly 100 into a patient's vascular lumen, such as a cone or curved cone, or a cylindrical profile with rounded edges.

[0029] The inner and outer edges of the pillars 202, 204, 206, 208 and 210 are rounded. Figure 2 , rounded outer edges 218a, 218b, 218c, and 218d can be seen on struts 202, 204, and 206, respectively. Similarly, rounded inner edges 220a, 220b, 220c, and 220d can be seen on struts 210 and 208, respectively. Rounding the outer edges of the blood outflow cage 110 reduces stress and wear on the vasculature when the blood pump assembly is inserted. This is particularly beneficial in embodiments where the blood pump assembly 100 is inserted percutaneously and used for right heart support, which requires the blood pump assembly 100 to be advanced through a tortuous path as it passes through the heart to its operating position. In addition, as described in U.S. Pat. No. 9,433,713, rounding the inner and outer edges of the blood outflow cage 110 also results in a significant reduction in hemolysis. The outer edges (e.g., 218a, 218b, 218c, and 218d) and the inner edges (e.g., 220a, 220b, 220c, and 220d) are filleted and may have any suitable radius. For example, but not limitation, for a blood outflow cage 110 having an outer diameter of 21 Fr (7 mm), the edge of each strut may be rounded to a radius between 0.07 mm and 0.21 mm. In this regard, the inner and outer edges do not have to have the same radius. For example, the inner edge of each strut may be rounded to a radius of approximately 0.08 mm, while the outer edge may be rounded to a radius of approximately 0.20 mm.

[0030] The shape of the openings defined by struts 202, 204, 206, 208, and 210 is also rounded. For example, in the opening defined by struts 202 and 204, the proximal end has rounded corners 216a and 216b, and the distal end has rounded junctions 222a and 222b where the struts transition into diffuser 212. Similarly, in the opening defined by struts 204 and 206, the proximal end has rounded corners 216c and 216d, and the distal end has rounded junctions 222b and 222c where the struts transition into diffuser 212. Rounded junctions 222a, 222b, and 222c fan out both tangentially and radially (fan out) such that all surfaces and edges of the struts have a smooth transition into diffuser 212. Rounding the shape of the openings through which blood exits cage 110 in this manner further improves blood flow. Specifically, using an internal rounded corner junction between the struts and the conical surface of diffuser 212 avoids squared corners and pockets that could exert shear stress on blood cells and cause hemolysis. The rounded corners of the openings can have any suitable shape and size. By way of example and not limitation, for a blood outflow cage 110 with an outer diameter of approximately 21 Fr (7 mm), the proximal corners (e.g., 216a, 216b, 216c, and 216d) can have an asymmetric radius where a major radius of approximately 2 mm transitions to a minor radius of approximately 1.431, with a conical Rho of approximately 0.35. Additionally, the rounded junctions (e.g., 222a, 222b, and 222c) can have a radius of approximately 0.3 mm. The use of an asymmetric radius can create a compound shape that provides a smooth transition surface for blood flow as the blood exits the window. However, one or more constant radii can also be used to form the window.

[0031] In addition to the above benefits, rounding the edges, corners, and junctions of the blood outflow cages described herein results in an improvement in manufacturability. Specifically, since automated machining processes rely on milling bits and cutting tools, these features facilitate manufacturing using automated machining processes. Additionally, by using an internal rounded corner transition at the junctions between struts 202, 204, 206, 208, 210 and diffuser 212, the junctions are made stronger, making automated machining more feasible, and blood outflow cage 110 can be machined from a single workpiece without welding or other joining methods.

[0032] Figure 3 depicts Figure 2 a second perspective view of blood outflow cage 110 depicted in Figure 3 depicts Figure 21, which is rotated so that support 202 is at the top of the blood outflow cage 110. Due to this orientation, only support 202, 204 and 206 are visible. In this view, support 208 and 210 are hidden behind support 206 and 204, respectively.

[0033] Figure 4 Describes the orientation Figure 3 As shown and along Figure 3 4-4 of the reference line 4-4. With this cut, the struts 204 and 206 are no longer visible, while the struts 208 and 210 are now visible. In addition, in this view, it can be seen that the hole 410 passes through the distal end of the blood flow cage 110. Specifically, the hole 410 extends from the proximal opening 408 in the diffuser 212 to the distal opening 412 in the end cap 214. The hole 410 is suitable for allowing a guide wire to pass through the distal end of the blood flow cage 110. In addition, the distal section of the hole 410 has a larger diameter, which is suitable for coupling with the tubular pigtail extension 112. However, like the pigtail extension 112, the hole 410 is an optional feature, and the present technology can be used with blood flow cages that do not include the hole 410, or blood flow cages that include holes of different configurations.

[0034] The cut surface of the blood outflow cage 110 is Figure 4 4 and 5. The cross-sectional view of the embodiment of the present invention is shown in FIG. 4 with oblique cross-sectional lines. This reveals another feature of the struts 202, 204, 206, 208 and 210. Specifically, as shown with respect to the cross-section of the strut 202, the strut includes a tapered section 404. As can be seen, the strut 202 has a substantially constant thickness between arrows 414 and 406, and then has a tapered section 404 as the strut 202 transitions to the thinner wall thickness of the cylindrical section 201 at arrow 402. This tapered section 404 corresponds to the fanning out of the strut 202 at the fillets 216e and 216a of the adjacent openings (not visible in this cross-sectional view). The tapering of the wall thickness, together with the fanning out of each strut, achieves a design that minimizes the proximal wall thickness while still adequately transitioning the pressure from the strut to the cylindrical section 201. This tapered section 404 can have any suitable profile and size. For example, the tapered section 404 can taper in a linear or curved manner. If curved, a single radius may be used, or two or more radii may be blended to form the tapered section 404. Thus, for a curve similar to Figure 4the design shown in, and assuming that the blood outflow cage 110 has an outer diameter of approximately 21 Fr (7 mm), the tapered section 404 may include (moving distally to proximally) a concave radius of approximately 6.5 mm that transitions to a convex radius of approximately 4.8 mm. Similarly, the wall thickness may taper from approximately 0.4 mm at or near arrow 406 to approximately 0.2 mm at or near arrow 402.

[0035] Figure 5A and Figure 5B depicts Figures 2 to 4 an isometric view of the blood outflow cage 110 depicted in. Specifically, Figure 5A depicts an isometric view of the exemplary blood outflow cage 110 looking in the distal direction, while Figures 2 to 4 depicts an isometric view of the exemplary blood outflow cage 110 looking in the proximal direction. Figure 5B looking in the proximal direction Figures 2 to 4 of the exemplary blood outflow cage 110.

[0036] Figure 6 depicts a cross-sectional view of the blood outflow cage 110 taken along line 6-6 of and looking in the direction of the arrow, i.e., towards the distal end of the blood outflow cage 110. The cut surfaces of each strut of the blood outflow cage 110 are shown in cross-hatching in Figure 5B looking in the direction of the arrow, i.e., towards the distal end of the blood outflow cage 110. The cut surfaces of each strut of the blood outflow cage 110 are shown in cross-hatching in Figure 6 .

[0037] As used herein, the terms “about,” “approximately,” “substantially,” and similar terms are intended to have a broad meaning consistent with the common and accepted usage by those of ordinary skill in the art to which the subject matter of this disclosure pertains. Those skilled in the art viewing this disclosure should understand that these terms are intended to allow the description of certain features without restricting the scope of these features to the precise numerical ranges provided. Accordingly, these terms should be interpreted as indicating a non-substantive or immaterial modification or variation of the subject matter being described and are considered to be within the scope of this disclosure.

[0038] For purposes of this disclosure, the term “coupled” means that two components are connected to each other either directly or indirectly. Such connection can be inherently stationary or movable. This connection can be achieved by the two components or the two components and any other intermediate component being integrally formed as a single unit with each other, or by the two components or the two components and any other intermediate component being attached to each other. Such connection can be substantially permanent or can be substantially removable or releasable.

[0039] It is important to note that the construction and arrangement of the devices or their components shown in the various exemplary embodiments are merely exemplary. Although only a few embodiments have been described in detail in this disclosure, those skilled in the art who view this disclosure will readily understand that many modifications (e.g., changes in the size, dimensions, structure, shape, and proportions of various elements, the values of parameters, the mounting arrangements, the use of materials, colors, orientations, etc.) are possible without materially departing from the novel teachings and advantages of the disclosed subject matter. For example, elements shown as integrally formed may be constructed of multiple parts or elements, the positions of the elements may be reversed or otherwise changed, and the nature or number or positions of discrete elements may be altered or varied. According to alternative embodiments, the order or sequence of any process or method steps may be varied or re-ordered. Other substitutions, modifications, changes, and omissions may be made in the design, operating conditions, and arrangement of the various exemplary embodiments without departing from the scope of this disclosure.

[0040] Although various embodiments have been described and illustrated herein, those of ordinary skill in the art will readily envision various other mechanisms and / or structures for performing the functions and / or obtaining the results and / or one or more of the advantages described herein, and each of these variations and / or modifications is considered to be within the scope of the embodiments of the invention described herein. More generally, those skilled in the art will readily understand that unless otherwise stated, any of the parameters, dimensions, materials, and configurations described herein are intended to be exemplary, and the actual parameters, dimensions, materials, and / or configurations will depend on the specific one or more applications for which the teachings of this invention are used. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, numerous equivalents to the specific embodiments of the invention described herein. Accordingly, it should be understood that the foregoing embodiments are presented by way of example only, and that the embodiments of the invention may be practiced otherwise than as specifically described and claimed within the scope of the appended claims and their equivalents. The embodiments of the invention of this disclosure relate to each and every separate feature, system, article, material, kit, and / or method described herein. Moreover, any combination of two or more such features, systems, articles, materials, kits, and / or methods, if such features, systems, articles, materials, kits, and / or methods are not mutually inconsistent, is also included within the inventive scope of this disclosure.

[0041] As used in the specification and claims, the indefinite articles "a" and "an" shall be understood to mean "at least one" unless explicitly indicated to the contrary. As used herein in the specification and claims, "or" shall be understood to have the same meaning as "and / or" as defined above. For example, when separating items in a list, "or" or "and / or" shall be understood to be inclusive, i.e., including at least one, but also including more than one of the elements or more than one of the items in the list of elements, and optionally other unlisted items. Only terms explicitly indicating the contrary, such as "only one of which" or "exactly one of which", shall refer to exactly one of the elements in a plurality of elements or in a list of elements. Generally, the term "or" as used herein shall be construed to indicate an exclusive alternative (i.e., "one or the other, but not both") only when followed by an exclusive term such as "either", "one of which", "only one of which" or "exactly one of which".

[0042] As used herein in the specification and claims, the phrase "at least one" in reference to a list of one or more elements shall be understood to mean at least one element selected from any one or more of the elements in the list of elements. The phrase "at least one" should not be understood to require at least one of each of the specifically listed elements within the list of elements. The phrase "at least one" should also not be understood to exclude any combination of elements in the list of elements. This definition also allows for elements other than those specifically identified in the list of elements referred to by the phrase "at least one" to optionally exist, whether or not related to those specifically identified elements. Thus, by way of non-limiting example, in one embodiment "at least one of A and B" (or equivalently, "at least one of A or B", or equivalently, "at least one of A and / or B") can mean at least one, optionally including more than one A, where B is absent (and optionally including elements other than B); in another embodiment, it can mean at least one, optionally including more than one B, where A is present (and optionally including elements other than A); in yet another embodiment, it can mean at least one, optionally including more than one A, and can mean at least one, optionally including more than one B (and optionally including other elements); and so on.

[0043] In the claims, as well as in the specification above, all transitional phrases such as "comprising", "including", "carrying", "having", "containing", "involving", "holding", "consisting of", "such as" and similar expressions shall be understood to be open-ended, i.e., to mean including but not limited to.

[0044] A claim should not be construed as limited to the order or elements described, unless so stated. It should be understood that various changes in form and detail can be made by those of ordinary skill in the art without departing from the spirit and scope of the appended claims. All embodiments falling within the spirit and scope of the appended claims and their equivalent expressions are claimed.

Claims

1. A blood outflow cage for use in an intravascular blood pump assembly and sized to pass through a patient's vascular lumen, the blood outflow cage comprising: A distal cap having an outer surface that is substantially conical, substantially curved conical, or substantially dome-shaped; A diffuser having an outer surface that is substantially conical or substantially curved conical, wherein the diffuser is disposed proximal to the distal cap; And A peripheral wall having: An inner surface; An outer surface; Two or more blood discharge openings, each blood discharge opening defined by two struts, wherein each strut has a rounded inner edge and outer edge and a rounded junction with the diffuser, and wherein the proximal end of each blood discharge opening has a rounded corner; And A first cylindrical section adjacent to the proximal end of each strut.

2. The blood outflow cage of claim 1, further comprising a hole passing through the diffuser and the distal cap.

3. The blood outflow cage of claim 1, wherein the thickness of the peripheral wall tapers from a first thickness at the struts to a second thickness at the first cylindrical section, wherein the first thickness is greater than the second thickness.

4. The blood outflow cage of claim 1, wherein the peripheral wall further comprises a second cylindrical section adjacent to the first cylindrical section, and wherein the outer diameter of the second cylindrical section is less than the outer diameter of the first cylindrical section.

5. The blood outflow cage of claim 1, further comprising a flexible tubular extension coupled to the distal cap.

6. The blood outflow cage of claim 5, wherein the distal end of the flexible tubular extension is curved in its relaxed state.

7. The blood outflow cage of claim 1, further comprising an inner rounded corner between the inner surface of each strut and the diffuser.

8. The blood outflow cage of claim 7, wherein the inner rounded corner has a radius of approximately 0.30 mm.

9. The blood outflow cage of claim 1, wherein the inner edges of the struts of the blood outflow cage each have a first radius between 0.07 mm and 0.21 mm, and the outer edges of the struts of the blood outflow cage each have a second radius between 0.07 mm and 0.21 mm.

10. The blood outflow cage of claim 1, wherein the blood outflow cage is made of a single piece of metal or polymer.

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