Blood pump distal outflow cage

Abstract

A blood pump assembly having a blood outflow cage component is designed to reduce stress on a patient's vasculature, reduce hemolysis and damage to the blood, and improve manufacturability. The blood pump assembly includes a blood outflow cage designed to discharge blood from a distal end of the blood pump assembly. The opening in the blood outflow cage has rounded edges, corners, and joints and smoothly transitions into a diffuser at the proximal end of the blood outflow cage. The thickness of the blood outflow cage struts may be further tapered as they transition into a thinner cylindrical section at the proximal end of the blood outflow cage.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Application No. 62 / 955,603, filed on December 31, 2019, the disclosure of which is incorporated by reference in its entirety. Technical Field

[0003] The present disclosure relates to a blood pump assembly. More particularly, the present disclosure relates to an outflow cage component disposed at a distal end of a blood pump assembly. Background Art

[0004] A blood pump assembly, such as an intracardiac blood pump assembly, is introduced into the heart to deliver blood from the heart to the arteries. For example, when used for right heart support, the blood pump assembly can draw blood from the inferior vena cava and discharge the blood into the pulmonary artery. In some cases, the 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, requiring the blood pump assembly to pass through several bends, which may introduce pressure to the patient's vascular system, especially by contacting the distal end of the blood pump assembly. In addition, when blood is drawn by the blood pump assembly, pumping blood via the blood pump assembly may damage the blood or cause hemolysis. Finally, since the blood outflow cage described herein incorporates a diffuser at its distal end, the joint between the support and the diffuser of the blood outflow cage may further interfere with blood flow and also complicate manufacturing. Summary of the invention

[0005] The devices and manufacturing methods and embodiments described herein provide a blood pump assembly having an outflow cage component designed to reduce pressure on the patient's vasculature, reduce hemolysis and damage to the blood, and improve manufacturability. The blood pump assembly includes a blood outflow cage designed to discharge blood from the distal end of the blood pump assembly. The blood outflow cage has rounded edges, corners, and joints. This provides several benefits. Rounding the outer edges of the blood outflow cage reduces pressure and wear on the vasculature when the blood pump assembly is inserted into the patient's body and advanced to its surgical site. As described in U.S. Patent No. 9,433,713, which is incorporated herein by reference, rounding the inner and outer edges of the blood outflow cage also leads to a significant reduction in hemolysis. In addition, because the blood outflow cage described herein incorporates a diffuser at its distal end, the use of fillets (i.e., the corners where the struts and diffusers intersect) at the joints between the struts and the diffuser further improves blood flow around these joints. This also results in fewer red blood cells being ruptured 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.

[0006] In one aspect, the present disclosure describes a blood outflow cage for an intravascular blood pump assembly and sized to pass through a patient's vascular lumen. The assembly includes a distal cover having a substantially conical, substantially curved conical, or substantially dome-shaped outer surface; a diffuser having a substantially conical or substantially curved conical outer surface. The diffuser is disposed proximal to the distal cover. The assembly has a peripheral wall having: an inner surface; an outer surface; two or more blood discharge openings, each of which is defined by two struts, wherein each strut has a rounded inner edge and an outer edge and a rounded joint 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 through the diffuser and the distal cover. In some aspects, the thickness of the peripheral wall tapers from a first thickness at the strut 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 smaller than the outer diameter of the first cylindrical section. The blood outflow cage optionally has a flexible tubular extension coupled to the distal cover. 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 fillet between the inner surface of each strut and the diffuser. In some aspects, the inner fillet has a radius of approximately 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.

[0007] In another aspect, the present disclosure describes a blood pump assembly that is sized for passing through a vascular lumen of a patient. The blood pump assembly includes: a pump; an impeller blade rotatably coupled to the pump; a blood inflow cage extending about the rotational axis of the impeller blade and having at least two blood inlet openings; a cannula in fluid communication with a first housing, a proximal end of the cannula coupled to the blood inflow cage; and a blood outflow cage coupled to a distal end of the cannula. The blood outflow cage includes a distal cover 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 cover; 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 outer edge and a rounded joint 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 through the diffuser and the distal cover 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 support 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 cover 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 fillet between the inner surface of each support and the diffuser of the blood outflow cage. In some aspects, the inner fillet has a radius of approximately 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

[0008] Figure 1 A blood pump assembly according to aspects of the present disclosure is shown.

[0009] Figure 2 A perspective view of a blood flow outflow cage according to aspects of the present disclosure is shown.

[0010] Figure 3 A perspective view of a blood flow outflow cage according to aspects of the present disclosure is shown.

[0011] Figure 4 A cross-sectional view of a blood flow out of a cage according to aspects of the present disclosure is shown.

[0012] Figure 5A and Figure 5B An isometric view of a blood flow outflow cage according to aspects of the present disclosure is shown.

[0013] Figure 6 A cross-sectional view of a blood flow out of a cage according to aspects of the present disclosure is shown. DETAILED DESCRIPTION

[0014] The present technology will now be described with reference to the following exemplary systems and methods.

[0015] 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 can encapsulate part or all of the blood pump 104 and / or can 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.

[0016] The blood pump 104 includes a rotatable impeller blade (not shown) that can be driven by an internal motor. For example, the blood pump 104 can include an internal electrical micro-axial pump having a pumping capacity of greater than 4 L / min and a diameter of 21 or 22 Fr. The blood pump 104 can also be driven by a remote source such as a motor located outside the patient's body coupled to a flexible drive shaft passing through the catheter 102.

[0017] The catheter 102 may house electrical wires that couple the motor of the blood pump 104 to one or more electronic controllers or other sensors. The catheter 102 may also house other components, such as cleaning fluid tubing, and / or other tubing configured to receive a guidewire.

[0018] 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 in operation.

[0019] The cannula 108 may include an elongated 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 so 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.

[0020] The blood outflow cage 110 includes one or more holes or openings configured to allow blood to flow from the cannula 108 into the blood pump assembly 100. The blood outflow cage 110 can be constructed of any suitable biocompatible material. For example, the blood outflow cage 110 can be formed of a biocompatible metal such as stainless steel, titanium, or a biocompatible polymer such as polyurethane. In addition, the surface of the blood outflow cage 110 can be treated in a variety of 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 can be laser textured. Although the blood outflow cage 110 can be manufactured from multiple pieces, the design described in more detail below facilitates 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 can also be manufactured using a rapid prototyping or injection molding process. Other features of the blood outflow cage 110 will be described below with respect to Figures 2 to 6 The examples are described in detail.

[0021] Pigtail extension 112 assists in stabilizing and positioning blood pump assembly 100 in the correct position in the pulmonary artery. Pigtail extension 112 can be solid or tubular. If tubular, pigtail extension 112 can be configured to allow a guidewire to pass through it to further assist in positioning blood pump assembly 100. Pigtail extension 112 can be of any suitable size. For example, the outer diameter of the pigtail extension can be in the range of 4-8Fr. Pigtail extension 112 can be at least partially composed of a flexible material and can be configured from a straight configuration to a partially curved configuration. Pigtail extension 112 can also have sections of different rigidity. For example, pigtail extension 112 may include: a proximal section, which is rigid enough to prevent its buckling, thereby keeping blood outflow cage 110 in a desired position; and a distal section, which is softer and has a lower rigidity, thereby providing a non-traumatic tip for contacting the pulmonary artery wall and allowing loading of the guidewire. In such cases, the proximal and distal sections of the pigtail extension 112 may be constructed from different materials, or may be constructed from the same material that has been processed to provide different stiffnesses.

[0022] However, the pigtail extension 112 is an optional structure. The present technology can also be used with blood pump assemblies that include extensions of different types, shapes, materials, and qualities. Likewise, the present technology 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.

[0023] The blood pump assembly 100 can be inserted percutaneously. 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. Once 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.

[0024] Figure 2-Figure 6 An exemplary blood flow out cage 110 is depicted in accordance with aspects of the present technique. Figure 2 , Figure 3 , Figure 4 , Figure 5A , Figure 5B ,and Figure 6 All reference numbers shared between are intended to denote the same features.

[0025] Figure 2 A perspective view of a blood outflow cage 110 is depicted. The distal end of the blood outflow cage 110 includes a diffuser 212 that transitions into a dome-shaped end cap 214. At its proximal end, the blood outflow cage 110 is comprised 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 couple with 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 five struts 202, 204, 206, 208, and 210 that define five openings through which blood can exit the blood outflow cage 110. Although Figure 2 The exemplary blood outflow cage 110 is shown with five struts, but any number of two or more struts may be used. The struts 202 , 204 , 206 , 208 , and 210 are connected to the distal end of the diffuser 212 .

[0026] The diffuser 212 is adapted to direct blood to flow out of the blood outflow cage 110. Figures 2 to 6 In the example of the embodiment, the shape of the curved cone is adopted, but other shapes, such as a cone without curvature, can also be adopted. 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.

[0027] 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.

[0028] 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.

[0029] The shape of the opening 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. The rounded junctions 222a, 222b, and 222c fan out tangentially and radially so that all surfaces and edges of the struts have a smooth transition to diffuser 212. In this way, the shape of the opening through which blood flows out of cage 110 is rounded, further improving blood flow. Specifically, the use of filleted joints between the struts and the conical surface of the diffuser 212 avoids squared corners and pockets that may exert shear stress on blood cells and cause hemolysis. The fillet of the opening may have any suitable shape and size. For example, but not by way of limitation, for a blood outflow cage 110 having an outer diameter of approximately 21 Fr (7 mm), the proximal corners (e.g., 216a, 216b, 216c, and 216d) may have an asymmetric radius, wherein a major radius of approximately 2 mm transitions to a minor radius of approximately 1.431, with a cone Rho of approximately 0.35. In addition, the rounded joints (e.g., 222a, 222b, and 222c) may have a radius of approximately 0.3 mm. The use of asymmetric radii may create a composite shape that provides a smooth transition surface for blood flow as the blood leaves the window. However, the window may also be formed using one or more constant radii.

[0030] In addition to the benefits described above, rounding the edges, corners, and joints of the blood outflow cage described herein results in improved manufacturability. Specifically, these features facilitate manufacturing using automated machining processes, since automated machining processes rely on rotating milling bits and cutting tools. Furthermore, by using fillet transitions at the joints between the struts 202, 204, 206, 208, 210 and the diffuser 212, the joints are made stronger, making automated machining more feasible, and the blood outflow cage 110 can be machined from a single piece without the need for welding or other joining methods.

[0031] Figure 3 Depicted Figure 2 1 is a second perspective view of blood flow out of cage 110. Specifically, Figure 3 Depicted 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.

[0032] Figure 4 Describes the orientation as 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.

[0033] 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 4, 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 from distal to proximal) 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.

[0034] Figure 5A and Figure 5B Depicted Figures 2 to 4 1 is an isometric view of blood flow out of cage 110. Specifically, Figure 5A Depicts looking in the distal direction Figures 2 to 4 An isometric view of an exemplary blood flow out of cage 110, and Figure 5B Depicted looking in the proximal direction Figures 2 to 4 An isometric view of an exemplary blood flow out of cage 110.

[0035] Figure 6 Depicted along Figure 5B The cross-sectional view of the blood outflow cage 110 taken along the line 6-6 and viewed along the arrow direction, i.e., toward the distal end of the blood outflow cage 110. The cross-sectional surface of each support of the blood outflow cage 110 is Figure 6 Shown with cross-hatching.

[0036] As used herein, the terms "approximately," "about," "substantially," and similar terms are intended to have a broad meaning consistent with common and accepted usage by those of ordinary skill in the art to which the subject matter of the present disclosure belongs. Those skilled in the art who review the present disclosure should understand that these terms are intended to allow for description of certain features described without limiting the scope of these features to the precise numerical ranges provided. Therefore, these terms should be interpreted as indicating insubstantial or inconsequential modifications or changes to the subject matter described and are considered to be within the scope of the present disclosure.

[0037] For purposes of this disclosure, the term "coupled" means that two components are directly or indirectly connected to each other. Such connection may be stationary or removable in nature. Such connection may be achieved by the two components or the two components and any other intermediate components being integrally formed as a single unitary body with each other, or the two components or the two components and any other intermediate components being attached to each other. Such connection may be permanent in nature, or may be removable or releasable in nature.

[0038] It is important to note that the construction and arrangement of the equipment or its parts shown in various exemplary embodiments are merely exemplary. Although only several embodiments are described in detail in the present disclosure, it will be readily understood by those skilled in the art who view the present disclosure that many modifications (e.g., changes in the size, dimensions, structure, shape and ratio of various elements, the value of parameters, the installation arrangement, the use of materials, colors, orientations, etc.) are possible without substantially departing from the novel teachings and advantages of the disclosed subject matter. For example, an element shown as integrally formed can be constructed of multiple parts or elements, the position of the element can be reversed or otherwise changed, and the nature or quantity or position of discrete elements can be changed or varied. According to optional embodiments, the order or sequence of any process or method steps can be changed or reordered. Without departing from the scope of the present disclosure, other substitutions, modifications, changes and omissions can also be made in the design, operating conditions and arrangement of various exemplary embodiments.

[0039] Although various embodiments have been described and illustrated herein, a person of ordinary skill in the art will readily conceive of various other mechanisms and / or structures for performing functions and / or obtaining results and / or one or more of the advantages described herein, and each of these changes and / or modifications is considered to be within the scope of the invention embodiments described herein. More generally, it will be readily understood by those skilled in the art that, unless otherwise specified, any parameters, dimensions, materials, and configurations described herein are intended to be exemplary, and actual parameters, dimensions, materials, and / or configurations will depend on the specific application or applications for which the present invention is taught. Those skilled in the art will recognize that, or can determine multiple equivalents of the specific invention embodiments described herein using only routine experiments. Therefore, it should be understood that the foregoing embodiments are presented only as examples, and within the scope of the appended claims and their equivalent expressions, the invention embodiments may be implemented differently from the specific description and protection claimed. The invention embodiments disclosed herein relate to each individual feature, system, article, material, kit, and / or method described herein. In addition, any combination of two or more such features, systems, articles, materials, kits, and / or methods is also included within the inventive scope of the present disclosure if such features, systems, articles, materials, kits, and / or methods are not mutually inconsistent.

[0040] The indefinite articles "one" and "an" used in the specification and claims should be understood to mean "at least one" unless clearly indicated to the contrary. As used herein in the specification and claims, "or" should be understood to have the same meaning as "and / or" as defined above. For example, when separating the listed items, "or" or "and / or" should be understood to be inclusive, that is, including at least one, but also including more than one of multiple elements or element enumerations, and optionally other unlisted items. Only terms that clearly indicate the opposite, such as "only one of them" or "exactly one of them", will refer to exactly one element in the inclusion of multiple elements or element enumerations. In general, the term "or" used herein should be interpreted as indicating exclusive substitution (i.e., "one or the other, but not both") only when exclusive terms such as "one of the two", "one of them", "only one of them" or "exactly one of them" follow.

[0041] As used herein in the specification and claims, the phrase "at least one" when referring to an enumeration of one or more elements should be understood to mean at least one element selected from any one or more elements in the enumeration of elements. The phrase "at least one" should not be understood to require at least one of each element specifically enumerated within the enumeration of elements. The phrase "at least one" should also not be understood to exclude any combination of elements in the enumeration of elements. This definition also allows that elements other than the elements specifically identified in the enumeration of elements referred to by the phrase "at least one" may optionally be present, whether or not related to those specifically identified elements. Thus, as a 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") may refer to at least one, optionally including more than one A, where B is not present (and optionally including elements other than B); in another embodiment, may refer to at least one, optionally including more than one B, where A is present (and optionally including elements other than A); in yet another embodiment, may refer to at least one, optionally including more than one A, and may refer to at least one, optionally including more than one B (and optionally including other elements); and so on.

[0042] In the claims and the foregoing description, all transitional phrases such as "comprises," "including," "carrying," "having," "containing," "involving," "maintaining," "consisting of," "such as," and similar expressions should be understood to be open-ended, meaning including but not limited to.

[0043] The claims should not be construed as limited to the described order or elements unless so stated. It should be understood that various changes in form and details may be made by one 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 equivalents are claimed for protection.

Claims

1. A blood outflow cage for an intravascular blood pump assembly and sized to pass through a patient's vascular lumen, the blood outflow cage include: a distal cap having a substantially conical, substantially curved conical, or substantially dome-shaped outer surface; a diffuser having a substantially conical or substantially curved conical outer surface, wherein the diffuser is disposed proximally of the distal cap; and A peripheral wall, the peripheral wall having: two or more blood discharge openings, each blood discharge opening being defined by two struts, each strut including a section of tapered thickness at a proximal end thereof, wherein each strut has rounded inner and outer edges and a rounded junction with the diffuser, and wherein the proximal end of each blood discharge opening has rounded corners; and A first cylindrical section adjoins the proximal end of each strut such that the tapered section of the strut transitions in thickness into the first cylindrical section.

2. The blood flow cage of claim 1 , further comprising a hole through the diffuser and the distal cover.

3. The blood flow cage of claim 1, wherein the thickness of each strut is greater than the thickness at the first cylindrical section.

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 smaller than the outer diameter of the first cylindrical section.

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

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 flow cage of claim 1, further comprising a fillet between an inner surface of each strut and the diffuser.

8. The blood flow cage of claim 7, wherein the fillet has a radius of approximately 0.30 mm.

9. The blood outflow cage of claim 1, wherein inner edges of struts of the blood outflow cage each have a first radius between 0.07 mm and 0.21 mm, and outer edges of 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 from a single piece of metal or polymer.

11. A blood pump assembly sized to pass through a vascular lumen of a patient, the blood pump assembly include: Pumps; an impeller blade rotatably coupled to the pump; a blood inflow cage extending about the axis of rotation of the impeller blade and having at least two blood inlet openings; a cannula in fluid communication with the blood inflow cage, a proximal end of the cannula coupled to the blood inflow cage; and A blood outflow cage coupled to the distal end of the cannula comprises: a distal cap having a substantially conical, substantially curved conical, or substantially dome-shaped outer surface; A diffuser having a substantially conical or substantially curved conical outer surface, wherein The diffuser is disposed proximal to the distal cap; and A peripheral wall, the peripheral wall having: two or more blood discharge openings, each blood discharge opening being defined by two struts, each strut including a section of tapered thickness at a proximal end thereof, wherein each strut has rounded inner and outer edges and a rounded junction with the diffuser, and wherein the proximal end of each blood discharge opening has rounded corners; and A first cylindrical section adjoins the proximal end of each strut such that the tapered section of the strut transitions in thickness into the first cylindrical section.

12. The blood pump assembly of claim 11, further comprising holes through the diffuser and the distal cap of the blood outflow cage.

13. The blood pump assembly of claim 11, wherein a thickness of each strut is greater than a thickness at the first cylindrical section.

14. The blood pump assembly of claim 11, wherein the peripheral wall of the blood outflow cage further comprises a second cylindrical section adjacent to the first cylindrical section, wherein the outer diameter of the second cylindrical section is smaller than the outer diameter of the first cylindrical section.

15. The blood pump assembly of claim 11, further comprising a flexible tubular extension coupled to a distal cover of the blood outflow cage.

16. The blood pump assembly of claim 15, wherein the distal end of the flexible tubular extension is curved in its relaxed state.

17. The blood pump assembly of claim 11, further comprising a fillet between an inner surface of each strut of the blood outflow cage and the diffuser.

18. The blood pump assembly of claim 17, wherein the fillet has a radius of approximately 0.30 mm.

19. The blood pump assembly of claim 11, wherein inner edges of the struts of the blood outflow cage each have a first radius between 0.07 mm and 0.21 mm, and outer edges of the struts of the blood outflow cage each have a second radius between 0.07 mm and 0.21 mm.

20. The blood pump assembly of claim 11, wherein the blood outflow cage is made from a single piece of metal or polymer.

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