Anti-sucking blood pump inlet

Abstract

To allow a heart pump assembly to continue to function.SOLUTION: A heart pump assembly includes: an impeller blade coupled to a rotor or a drive shaft; a cannula; a distal projection coupled to a distal end of the cannula; and a blood inlet having a plurality of apertures. The apertures are radially oriented and disposed about the cannula. The apertures at least include a first ring of apertures which are proximal to the distal projection, and a second ring of apertures which are proximal of the first ring of apertures. The apertures can allow the heart pump assembly to continue to function if anatomical structures or tissues become suctioned to a portion of the heart pump.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Patent Application No. 62 / 382,471, filed Sep. 1, 2016, the contents of which are incorporated by reference herein in their entirety. [Background technology]

[0002] background A blood pump, such as a percutaneous intracardiac blood pump assembly, can be introduced into the heart to pump blood out of the heart into the arteries. When the blood pump assembly is activated in the heart, it draws blood from the left ventricle and ejects it into the aorta, or draws blood from the right ventricle and ejects it into the pulmonary artery. Some heart pump assemblies draw blood through an inflow opening into a cannula and eject it from the cannula through an outflow opening into the aorta. Sometimes the inflow opening sticks to the interior of the ventricle in which it is located or to other structures, such as the mitral valve and / or chordae tendineae. When this sticking occurs, the flow of blood into the pump and / or through the cannula is blocked or impeded, reducing the support provided to the heart. Summary of the Invention

[0003] overview The systems, devices, and methods described herein provide a heart pump assembly with an improved inflow opening. The inflow opening is designed to prevent or reduce the tendency of the inflow opening to become stuck inside the patient's heart or vasculature. In particular, the inflow opening can prevent the pump inlet from sucking valve leaflets (e.g., mitral valve leaflets) into the inlet. This can reduce the risk of blockage of the opening and allow the pump to provide more blood pumping support to the heart. The improved opening can also reduce the risk of damage to heart structures that may become stuck to the pump.

[0004] The heart pump includes multiple inflow openings. The inflow openings can be located at a distal end portion of the cannula of the heart pump (e.g., in the case of a pump designed to assist the left ventricle). The inflow openings can be arranged in two or more rings or rows offset from each other along the longitudinal axis of the pump. The use of multiple rings or rows of openings rather than a single ring of openings can make each opening smaller, which can reduce the risk of a heart structure (e.g., a valve) entering the inlet through the opening. Furthermore, the additional inflow openings provide redundancy, such that even if one subset of openings is blocked, there are additional openings through which blood can pass as it enters the pump. The outer edges of the openings can be defined by struts coupled to the cannula. The struts can act as shields to prevent valve leaflets from sucking into or out of the pump.

[0005] In one aspect, a heart pump assembly includes a rotor, a motor coupled to the rotor, impeller blades coupled to the rotor such that rotation of the rotor rotates the impeller blades and pumps blood, a cannula, a distal projection coupled to a distal end of the cannula, and a blood inlet including a plurality of apertures oriented and arranged radially about the circumference, the plurality of apertures including at least a first ring of apertures proximal to the atraumatic tip and a second ring of apertures proximal to the first ring of apertures.

[0006] In some embodiments, the first opening in the first ring of openings has an area greater than the area of ​​the second opening in the second ring of openings. In some embodiments, the first opening in the first ring of openings and the second opening in the second ring of openings are oval. In some embodiments, the heart pump assembly includes a third ring of openings proximal to the second ring. In some embodiments, the heart pump assembly includes a fourth ring of openings proximal to the third ring.

[0007] In some embodiments, a first opening in the first ring of openings and a third opening in the third ring of openings are aligned along an axis on the surface of the cannula that is parallel to the longitudinal axis of the cannula, hi some embodiments, a second opening in the second ring of openings is aligned with a fourth opening in the fourth ring of openings along an axis on the surface of the cannula that is parallel to the longitudinal axis of the cannula.

[0008] In some embodiments, the first opening in the first ring of openings has a height, measured parallel to the longitudinal axis of the cannula, that is greater than the height of any of the second opening, the third opening, or the fourth opening. In some embodiments, the height of the first opening is less than 9 mm. In some embodiments, the height of the second opening is less than 3 mm. In some embodiments, the width of the second opening is less than 4 mm. In some embodiments, the area of ​​the first opening is less than 20 mm. 2 In some embodiments, the area of ​​the second opening is less than 12 mm 2 In some embodiments, the plurality of apertures is formed on an inflow cage coupled to the cannula. In some embodiments, the inflow cage is constructed from stainless steel. In some embodiments, the plurality of apertures is formed near a terminal end of the cannula.

[0009] In some embodiments, some of the plurality of apertures are oval. In some embodiments, some of the plurality of apertures are circular. In some embodiments, some of the plurality of apertures are teardrop shaped with a rounded edge facing the distal end of each aperture and a sharp edge facing the proximal side of each aperture. In some embodiments, a first aperture in the first ring of apertures has a smaller area than a second aperture in the second ring of apertures. In some embodiments, a first aperture in the first ring of apertures has the same area as a second aperture in the second ring of apertures. In some embodiments, a distal end portion of the cannula includes an inflow cage. In some embodiments, a distal edge of the first aperture is formed by a base of the atraumatic tip.

[0010] In some embodiments, each of the plurality of apertures is defined by an inner edge that intersects the interior of the cannula and an outer edge that intersects a surface of the cannula. In some embodiments, the outer edge of each of the plurality of apertures is rounded. In some embodiments, the outer edge of each of the plurality of apertures is chamfered. In some embodiments, the heart pump assembly is sized for percutaneous insertion.

[0011] In another aspect, a heart pump assembly includes a rotor, a motor coupled to the rotor, impeller blades coupled to the rotor such that rotation of the rotor rotates the impeller blades and pumps blood, a cannula, and a blood inlet including a plurality of apertures oriented and arranged radially about the circumference, the plurality of apertures including at least a first ring of apertures and a second ring of apertures proximal to the first ring of apertures, each aperture of the first ring of apertures having a larger area than the apertures of the second ring of apertures.

[0012] In some embodiments, the first opening in the first ring of openings and the second opening in the second ring of openings are oval. In some embodiments, the heart pump assembly includes a third ring of openings proximal to the second ring. In some embodiments, the heart pump assembly includes a fourth ring of openings proximal to the third ring. In some embodiments, the first opening in the first ring of openings and the third opening in the third ring of openings are aligned along an axis on the surface of the cannula that is parallel to the longitudinal axis of the cannula. In some embodiments, the second opening in the second ring of openings is aligned with the fourth opening in the fourth ring of openings along an axis on the surface of the cannula that is parallel to the longitudinal axis of the cannula.

[0013] In some embodiments, the first opening in the first ring of openings has a height, measured parallel to the longitudinal axis of the cannula, that is greater than the height of any of the second opening, the third opening, or the fourth opening. In some embodiments, the height of the first opening is less than 9 mm. In some embodiments, the height of the second opening is less than 3 mm. In some embodiments, the width of the second opening is less than 4 mm. In some embodiments, the area of ​​the first opening is less than 20 mm. 2 In some embodiments, the plurality of apertures is formed on an inflow cage coupled to the cannula. In some embodiments, the inflow cage is constructed from stainless steel. In some embodiments, the plurality of apertures is formed near a terminal end of the cannula.

[0014] In some embodiments, each of the plurality of apertures is defined by an inner edge that intersects the interior of the cannula and an outer edge that intersects a surface of the cannula. In some embodiments, the outer edge of each of the plurality of apertures is rounded. In some embodiments, the outer edge of each of the plurality of apertures is chamfered. In some embodiments, the heart pump assembly is sized for percutaneous insertion.

[0015] In another aspect, a method of manufacturing a heart pump assembly includes coupling impeller blades to a rotor, inserting the impeller blades into a housing, coupling a cannula to the housing, and coupling an inflow cage to the cannula, the inflow cage including a plurality of apertures oriented radially around the inflow cage, the plurality of apertures being disposed in at least a first ring of apertures and a second ring of apertures proximal to the first ring of apertures.

[0016] In some embodiments, the inflow cage includes a third ring of apertures proximal to the second ring of apertures. In some embodiments, the inflow cage includes a fourth ring of apertures proximal to the third ring of apertures. In some embodiments, each of the plurality of apertures includes an outer edge formed by a tumbling process. In some embodiments, the plurality of apertures are formed near a terminal end of the cannula. In some embodiments, the method also includes coupling a distal projection to a distal end of the inflow cage. The distal projection is distal to the plurality of apertures, with a base of the distal projection forming a distal edge of the first ring of apertures.

[0017] In another aspect, a method of operating a heart pump assembly includes using a motor to rotate an impeller about an axis of rotation to draw blood into a cannula of the heart pump assembly through a plurality of blood inlet openings and expelling blood from the heart pump assembly through a plurality of blood outlet openings disposed at a proximal end portion of the cannula proximal to the pump, the blood inlet openings being oriented radially around the cannula and arranged in at least two rings at a distal end of the cannula.

[0018] Variations and modifications will occur to those skilled in the art after considering this disclosure. The disclosed features may be embodied in any combination and subcombination (including multiple subcombinations and subcombinations) with one or more other features described herein. For example, although various specific aperture arrangements are described herein, the heart pump assembly may be configured to have any number of apertures arranged in any suitable number of rings. Furthermore, the apertures may have any suitable size, shape, or arrangement. The various features described above, including any of their components, may be combined or integrated into other systems. Moreover, certain features may be omitted or not embodied. [The present invention 1001] With rotor; a motor coupled to the rotor; an impeller blade coupled to the rotor such that rotation of the rotor rotates the impeller blade and propels blood; With cannula; a distal prong coupled to a distal end of the cannula; a blood inlet including a plurality of openings oriented and disposed radially about the circumference; 1. A heart pump assembly comprising: the plurality of apertures including at least a first ring of apertures and a second ring of apertures proximal to the first ring of apertures; The heart pump assembly. [The present invention 1002] A heart pump assembly of the present invention 1001, wherein a first opening in the first ring of openings has an area greater than an area of ​​a second opening in the second ring of openings. [The present invention 1003] The heart pump assembly of the present invention 1002, wherein the first openings in the first ring of openings and the second openings in the second ring of openings are oval. [The present invention 1004] The heart pump assembly of the present invention 1003 further comprising a third ring of apertures proximal to the second ring. [The present invention 1005] The heart pump assembly of the present invention 1004 further comprising a fourth ring of apertures proximal to the third ring. [The present invention 1006] A heart pump assembly of the present invention 1005, wherein a first opening in the first ring of openings and a third opening in the third ring of openings are aligned along an axis on the surface of the cannula parallel to the longitudinal axis of the cannula. [The present invention 1007] A heart pump assembly of the present invention 1006, wherein the second opening in the second ring of openings is aligned with the fourth opening in the fourth ring of openings along an axis on the surface of the cannula parallel to the longitudinal axis of the cannula. [The present invention 1008] A heart pump assembly of the present invention 1007, wherein a first opening in a first ring of openings has a height measured parallel to the longitudinal axis of the cannula that is greater than the height of any of the second opening, the third opening or the fourth opening. [The present invention 1009] A heart pump assembly of the present invention 1008, wherein the height of the first opening is less than 9 mm. [The present invention 1010] A heart pump assembly according to the present invention 1009, wherein the height of the second opening is less than 3 mm. [The present invention 1011] The area of ​​the first opening is 20 mm 2 The heart pump assembly of the present invention 1010, [The present invention 1012] A heart pump assembly of the present invention 1001, wherein a plurality of openings are formed on an inflow cage coupled to a cannula. [The present invention 1013] A heart pump assembly according to the present invention 1012, wherein the inflow cage is constructed of stainless steel. [The present invention 1014] A heart pump assembly of the present invention 1001, wherein a plurality of openings are formed near the end of the cannula. [The present invention 1015] A heart pump assembly of the present invention 1001, wherein each of a plurality of openings is defined by an inner edge that intersects with the inside of the cannula and an outer edge that intersects with the outer surface of the cannula, and the outer edges of each of the plurality of openings are rounded. [The present invention 1016] A heart pump assembly of the present invention 1001, wherein each of a plurality of openings is defined by an inner edge that intersects with the inside of the cannula and an outer edge that intersects with the outer surface of the cannula, and the outer edge of each of the plurality of openings is chamfered. [The present invention 1017] A heart pump assembly of the present invention 1001 that is sized for percutaneous insertion. [The present invention 1018] With rotor; a motor coupled to the rotor; an impeller blade coupled to the rotor such that rotation of the rotor rotates the impeller blade and propels blood; With cannula; a blood inlet including a plurality of openings oriented and arranged radially about a circumference, the plurality of openings including at least a first ring of openings and a second ring of openings proximal to the first ring of openings; 1. A heart pump assembly comprising: the first ring of apertures includes a first aperture and the second ring of apertures includes a second aperture, the first aperture having an area greater than an area of ​​the second aperture; The heart pump assembly. [The present invention 1019] A heart pump assembly according to the present invention 1018, wherein the area of ​​the first opening is at least two times greater than the area of ​​the second opening. [The present invention 1020] A heart pump assembly of the present invention 1019, wherein the first opening has a height measured parallel to the longitudinal axis of the cannula, the height being greater than a height of the second opening measured parallel to the longitudinal axis of the cannula. [The present invention 1021] A heart pump assembly of the present invention 1020, wherein the height of the first opening is at least two times greater than the height of the second opening. [The present invention 1022] A heart pump assembly according to the present invention 1021, wherein each opening of the first ring of openings has an area greater than an area of ​​each opening of the second ring of openings. [The present invention 1023] The heart pump assembly of the present invention 1022 further comprising a third ring of apertures proximal to the second ring. [The present invention 1024] The heart pump assembly of the present invention 1023 further comprising a fourth ring of openings proximal to the third ring. [The present invention 1025] A heart pump assembly of the present invention 1024, wherein the height of the first opening is greater than the height of the third opening of the third ring of openings or the height of the fourth opening of the fourth ring of openings. [The present invention 1026] A heart pump assembly of the present invention 1025, wherein the height of the first opening is less than 9 mm. [The present invention 1027] A heart pump assembly according to the present invention 1026, wherein the height of the second opening is less than 3 mm. [The present invention 1028] The area of ​​the first opening is 20 mm 2 The heart pump assembly of the present invention 1027, [The present invention 1029] A heart pump assembly of the present invention 1025, wherein the first opening in the first ring of openings and the third opening in the third ring of openings are aligned along an axis on the outer surface of the cannula parallel to the longitudinal axis of the cannula. [The present invention 1030] A heart pump assembly of the present invention 1029, wherein the second opening in the second ring of openings is aligned with the fourth opening in the fourth ring of openings along an axis on the outer surface of the cannula parallel to the longitudinal axis of the cannula. [The present invention 1031] A heart pump assembly according to the present invention 1017, wherein a plurality of openings are formed on an inflow cage coupled to a cannula. [The present invention 1032] A heart pump assembly according to the present invention 1031, wherein the inflow cage is constructed of stainless steel. [The present invention 1033] A heart pump assembly according to the present invention 1017, wherein a plurality of openings are formed near the terminal end of the cannula. [The present invention 1034] A heart pump assembly of the present invention 1017, wherein each of the plurality of openings is defined by an inner edge that intersects with the inside of the cannula and an outer edge that intersects with the outer surface of the cannula, and the outer edges of each of the plurality of openings are rounded. [The present invention 1035] A heart pump assembly of the present invention 1017, wherein each of a plurality of openings is defined by an inner edge that intersects with the inside of the cannula and an outer edge that intersects with the outer surface of the cannula, and the outer edge of each of the plurality of openings is chamfered. [The present invention 1036] A heart pump assembly of the present invention 1017 that is sized for percutaneous insertion. [The present invention 1037] A method of manufacturing a heart pump assembly, comprising the steps of: coupling the impeller blades to the rotor; inserting the impeller blade into a housing; coupling a cannula to the housing; and coupling an inflow cage to the cannula, the inflow cage includes a plurality of apertures oriented radially about a circumference of the inflow cage, the plurality of apertures being disposed in at least a first ring of apertures and a second ring of apertures proximal to the first ring of apertures; coupling a distal protrusion to a distal end of the inflow cage, The distal projection is distal to the plurality of openings and the base of the distal projection forms a distal edge of a first ring of openings. [The present invention 1038] The method of claim 1037, wherein the inflow cage further comprises a third ring of openings proximal to the second ring of openings. [The present invention 1039] The method of claim 1038, wherein the inflow cage further comprises a fourth ring of openings proximal to the third ring of openings. [The present invention 1040] The method of claim 1039, wherein each of the plurality of openings included in the inflow cage includes an outer edge formed by a tumbling process. [Brief description of the drawings]

[0019] The above and other objects and advantages will become apparent from the following detailed description considered in conjunction with the accompanying drawings, in which like reference numerals refer to like parts throughout.

[0020] [Figure 1] 1 illustrates an exemplary prior art pump assembly. [Diagram 2] 1 illustrates an exemplary embodiment of a heart pump assembly including multiple openings in a distal end portion. [Diagram 3] 1 illustrates an exemplary embodiment of a heart pump assembly including multiple openings disposed in a ring at a distal end portion. [Figure 4] 1 illustrates an exemplary embodiment heart pump assembly including three rings of openings at a distal end portion. [Diagram 5] 1 shows a perspective view of a distal end portion of an exemplary embodiment of a heart pump assembly having four rings of openings. [Figure 6] FIG. 1 shows a front view of a distal end portion of an exemplary embodiment of a heart pump assembly having four rings of openings. [Figure 7] 1 shows a perspective view of a distal end portion of an exemplary embodiment of a heart pump assembly having two rings of rotationally offset openings. [Figure 8] 1 shows a perspective view of a distal end portion of an exemplary embodiment of a heart pump assembly having two rotationally aligned openings. [Figure 9] 1 shows a perspective view of a distal end portion of an exemplary embodiment of a heart pump assembly having multiple rotationally aligned openings. [Figure 10] 1 shows a front view of a distal end portion of an exemplary embodiment of a heart pump assembly having multiple round openings. [Figure 11] 1 shows a perspective view of a distal end portion of an exemplary embodiment of a heart pump assembly having an oval distal opening and multiple round openings. [Figure 12] 1 shows a front view of a distal end portion of an exemplary embodiment of a heart pump assembly having a distal teardrop-shaped opening and multiple round openings. [Figure 13] 1 shows a front view of a distal end portion of an exemplary embodiment of a heart pump assembly having a distal teardrop-shaped opening and multiple teardrop-shaped openings arranged in a ring. [Figure 14] 1 shows a front view of a distal end portion of an exemplary embodiment of a heart pump assembly having an arrangement of apertures arranged in closely spaced rings. [Figure 15]13A-13C show front views of the distal end portion of an exemplary embodiment of a heart pump assembly having an alternative arrangement of apertures arranged in a moderately spaced ring. [Figure 16] 13A shows a front view of a distal end portion of an exemplary embodiment of a heart pump assembly having an alternative arrangement of apertures arranged in widely spaced rings. [Figure 17] 1 shows a front view of a distal end portion of an exemplary embodiment heart pump assembly having an alternative arrangement of apertures disposed in a first ring of long apertures and a second ring of shorter apertures. [Figure 18] A front view of the distal end portion of an exemplary embodiment heart pump assembly is shown having an alternative arrangement of openings arranged in a first ring of long openings and a second ring of shorter openings spaced apart from the first ring. [Figure 19] 13 shows a front view of a distal end portion of an exemplary embodiment of a heart pump assembly having an alternative arrangement of apertures arranged in four rings of similarly sized apertures. [Figure 20] 13A-13C show front views of the distal end portion of an exemplary embodiment of a heart pump assembly having an alternative arrangement of apertures arranged in four rings of different sized apertures. [Figure 21] 13A-13C show front views of a distal end portion of an exemplary embodiment of a heart pump assembly having an alternative arrangement of openings with chamfered edges. [Figure 22] 13A-13C show front views of a distal end portion of an exemplary embodiment of a heart pump assembly having an alternative arrangement of openings with rounded edges. [Figure 23] 13A-13C show front views of a distal end portion of an exemplary embodiment of a heart pump assembly having an alternative arrangement of openings. [Figure 24] 1 shows a plot displaying the predicted flow rate of a fluid through a number of openings in an exemplary arrangement of an exemplary embodiment. [Diagram 25] 1 illustrates an exemplary embodiment of a percutaneous pump having multiple openings at a distal end portion inserted into a patient's blood vessel. [Figure 26] 1 is a flow chart of a method of manufacturing an exemplary embodiment of a heart pump having multiple openings in a distal end portion. [Figure 27] 13 is a flow chart of a method of using an exemplary embodiment of a heart pump having multiple openings in a distal end portion. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Detailed Description To provide a general understanding of the systems, methods and devices described herein, certain exemplary embodiments are described. Although the embodiments and features described herein are described with reference to a particular number, size and shape of apertures, it will be understood that the heart pump assembly can be configured with any suitable number of apertures arranged in any number of rings, without being limited to the arrangements described herein. Additionally, the apertures can have any suitable size, shape or arrangement.

[0022] The systems, devices and methods described herein provide a heart pump assembly with an improved inflow opening. The inflow opening is designed to prevent or reduce the tendency of the inflow opening to become stuck inside the patient's heart or vasculature. In particular, the inflow opening can prevent the pump inlet from sucking valve leaflets (e.g., mitral valve leaflets) into the inlet. This can reduce the risk of blockage of the opening and allow the pump to provide more blood pumping support to the heart. The improved opening can also reduce the risk of damage to heart structures that may become stuck to the pump.

[0023] The heart pump includes multiple inflow openings. The inflow openings can be located at a distal end portion of the cannula of the heart pump (e.g., in the case of a pump designed to assist the left ventricle). The inflow openings can be arranged in two or more rings or rows offset from each other along the longitudinal axis of the pump. The use of multiple rings or rows of openings rather than a single ring of openings can make each opening smaller, which can reduce the risk of a heart structure (e.g., a valve) entering the inlet through the opening. Furthermore, the additional inflow openings provide redundancy, so that even if one subset of openings is blocked, there are additional openings through which blood can pass as it enters. The outer edges of the openings can be defined by struts coupled to the cannula. The struts can act as shields to prevent the valve leaflets from sucking into or out of the openings.

[0024] FIG. 1 illustrates an exemplary prior art heart pump assembly 100. The heart pump assembly 100 includes a motor housing 102, a cannula assembly 108, a plurality of apertures 116, a plurality of blood discharge apertures 124, and a protrusion or atraumatic tip 112. The cannula assembly 108 includes a proximal end 111, a cannula body 109, an inflow cage 113, a distal end 110, a distal end portion 114, and a teardrop portion 142. The motor housing 102 has a proximal end 107 and a distal end 106. The plurality of apertures 116 are disposed in one ring 118 in the inflow cage 113 at the distal end portion 114 of the cannula assembly 108. The atraumatic tip 112 is coupled to the cannula assembly 108 at the distal end 110 of the cannula assembly 108 at the teardrop portion 142.

[0025] The heart pump assembly 100 draws blood through the plurality of openings 116 and into the cannula assembly 108. The pump ejects blood proximal to the proximal end 111 of the cannula assembly 108 through a plurality of blood ejection openings 124. The heart pump assembly 100 may be percutaneously inserted into the heart through the aorta. The plurality of openings 116 may be positioned in the left ventricle past the aortic valve to draw blood from the left ventricle and eject the blood into the aorta. Although the atraumatic tip 112 spaces the heart pump assembly 100 away from the heart wall, in some instances the plurality of openings 116 may be positioned near the wall of the heart or various heart structures, such as the leaflets of the mitral valve. Each of the plurality of openings 116 has a large area that may allow the heart structures, such as the valve leaflets, to be sucked into the openings 116 and through the openings 116 into the cannula assembly 108. This can block some or all of the flow of blood into the cannula assembly 108. When the flow of blood through the cannula assembly 108 is blocked, the heart pump assembly 100 is able to provide less assistance to the heart.

[0026] 2 illustrates a specific embodiment of a modified heart pump assembly 200 having a plurality of openings disposed into the rings. The heart pump assembly 200 includes a motor housing 202, a cannula assembly 208, a plurality of openings 216, a plurality of blood outlets 224, and an atraumatic tip 212. The cannula assembly 208 has a proximal end 206, a cannula body 209, an inflow cage 213, a distal end 210, a distal end portion 214, and a teardrop portion 242. The atraumatic tip 212 is coupled to the cannula assembly 208 at the distal end 210 of the cannula assembly 208 at the teardrop portion 242. The plurality of openings 216 are disposed in the inflow cage 213 at the distal end portion 214 of the cannula assembly 208. Each of the plurality of openings 216 has a smaller area than the plurality of openings 116 illustrated in FIG. 1 and are disposed into the plurality of rings. Distal end portion 214 of cannula assembly 208 includes a first ring of apertures 218, a second ring of apertures 220, and a third ring of apertures 230. Inflow cage 213, which includes a plurality of apertures 216, is approximately the same length as inflow cage 113 of prior art pump 100, however, plurality of apertures 216 includes more smaller apertures than the apertures of prior art pump 100.

[0027] The smaller openings 216 disposed in the rings 218, 220, and 230 reduce the tendency of the openings 216 to suck into the interior of the patient's heart. In particular, the smaller openings 216 prevent the heart pump assembly 200 from sucking the valve leaflets into the openings 216. This can reduce the risk of blockage of the openings 216, thereby allowing the heart pump assembly 200 to provide more support to the heart. The openings 216 can also reduce the risk of damage to heart structures that might otherwise be sucked by the heart pump assembly 200. The heart pump assembly 200 can be modified in any number of ways. For example, the embodiment of FIG. 2 and any of the other embodiments herein can eliminate a motor housing. Instead, the motor can be configured to be located outside the patient's body and operatively coupled to the rotor via a drive shaft or cable.

[0028] 3 shows a diagram illustrating some embodiments of a heart pump assembly 300, such as the heart pump assembly 200 of FIG. 2, including a plurality of apertures 316 in a distal end portion 314. The heart pump assembly 300 includes a motor housing 302, an impeller blade 304, a cannula assembly 308, a plurality of apertures 316, and an atraumatic tip 312. The motor housing 302 has a distal end 306 and a proximal end 307. The impeller blade 304 is rotatable relative to the cannula assembly 308. The cannula assembly 308 includes a cannula body 309 having a proximal end 311, a distal end 310, a distal end portion 314, a teardrop portion 342, and a periphery 322. The cannula body 309 is coupled to the distal end 306 of the motor housing 302. The plurality of apertures 316 are disposed into a first ring 318 and a second ring 320. A first ring 318 is disposed at a distal end of the distal end portion 314 and a second ring 320 is disposed proximal to the first ring 318. In some embodiments, a plurality of apertures 316 are formed in the distal end portion 314 of the cannula assembly 308. In certain embodiments, a plurality of apertures 316 are formed in an inflow cage (not shown) that is separate from but coupled to the distal end portion 314 of the cannula assembly 308. The plurality of apertures are separated by a plurality of struts, e.g., 317a-c. An atraumatic tip 312 is coupled to the distal end 310 of the cannula assembly 308.

[0029] The first ring 318 includes openings 318a-c. The second ring 320 includes openings 320a-c. Although the first ring 318 and the second ring 320 are shown with three openings (318a-c and 320a-c), respectively, the multiple openings 316 in the first ring 318 and the second ring 320 can extend around the entire circumference 322 of the cannula body 309. The first ring 318 and the second ring 320 can each include any suitable number of openings. In some embodiments, the number of openings in the first ring 318 or the second ring 320 is 3, 4, 5, 6, 7, 8, 9, 10, or any other suitable number of openings. In some embodiments, the number of openings in the first ring 318 is the same as the number of openings in the second ring 320, although this is not required. In some embodiments, the number of openings in the first ring 318 is fewer than the number of openings in the second ring 320. In some embodiments, there are more openings in the first ring 318 than in the second ring 320 .

[0030] The heart pump assembly 300 draws blood into the cannula assembly 308 by rotation of the impeller blades 304. The blood enters the cannula assembly 308 through a plurality of openings 316 in the distal end portion 314 of the cannula assembly 308. The heart pump assembly 300 may be positioned in the heart in such a manner that the mitral valve leaflets are in close proximity to the plurality of openings 316, and in some cases, the mitral valve leaflets may be sucked into some of the plurality of openings 316, temporarily blocking blood from entering through the plurality of openings 316. Because the plurality of openings 316 are of small diameter, the openings 316 are less likely to allow the valve leaflets to enter the heart pump assembly 300 from the inlet. This leaves the interior of the cannula assembly 308 open for the passage of blood. Additionally, the struts 317a-c between the plurality of openings 316 act as a shield to prevent the valve leaflets and other tissue from sucking into the plurality of openings 316. Valve leaflets or other portions of the anatomy that are sucked into or into some of the plurality of openings 316 reduce the area through which blood can pass as it enters the cannula assembly 308, potentially reducing the flow rate of blood through the heart pump assembly 300. The plurality of openings 316 located at the distal end portion 314 of the cannula assembly 308 increases the likelihood that some of the plurality of openings 316 will not be blocked. Even if a subset of the plurality of openings 316 is blocked, blood can still enter the heart pump assembly 300 through the remainder of the plurality of openings 316.

[0031] The plurality of openings 316 are shown having an oval shape. The plurality of openings 316 may have any suitable shape for allowing blood to enter the cannula assembly. For example, the plurality of openings 116 may be oval, elliptical, square, teardrop, round, or any other suitable shape. The shape of the openings 318a-c of the first ring 318 may differ from the shape of the openings 320a-c of the second ring 320. In some embodiments, the edges of the plurality of openings 316 are rounded or chamfered. Rounded openings, i.e., openings having rounded edges, may reduce the risk of hemolysis or other damage to blood when blood enters the plurality of openings 316. As shown, each of the openings 318a-c of the first ring 318 has a larger area than each of the openings 320a-c of the second ring 320. In some embodiments, each of the openings 318a-c of the first ring 318 has a smaller area than each of the openings 320a-c of the second ring 320. In certain embodiments, each of the openings 318a-c of the first ring 318 has the same area as each of the openings 320a-c of the second ring 320.

[0032] An atraumatic tip 312 coupled to the distal end 310 of the cannula assembly 308 spaces the plurality of openings 316 from the inner surface of the heart. This spacing prevents the plurality of openings 316 from sticking to the wall of the heart, a heart valve (e.g., the mitral valve), or any other anatomical structure in the heart. This can reduce the risk of blockage of the plurality of openings 316 and can reduce or prevent damage to the heart tissue. The atraumatic tip 312 can be shaped as a flexible extension with a pigtail as shown in FIG. 3. In some embodiments, the atraumatic tip 312 is configured as a straight extension or a bulb. In some embodiments, the atraumatic tip 312 includes a lumen for passing a guidewire through the atraumatic tip 312.

[0033] In sum, both the atraumatic tip 312 and the arrangement of the apertures 316 help to prevent or reduce the risk of the pump inlet becoming blocked by the heart wall, valve leaflets, or other anatomical structures. The atraumatic tip 312 acts as a mechanical spacer to prevent sticking of the apertures to the inner surface of the heart, and the arrangement of the apertures 316 and struts 317a-c act as a shield to prevent ingress of tissue into the apertures 316. Thus, the atraumatic tip 312 and the arrangement of the apertures 316 together help to preserve proper function of the heart pump assembly 301.

[0034] 4 shows a diagram illustrating a heart pump assembly 400, such as the heart pump assembly 200 of FIG. 2, including three rings of openings at a distal end portion 414 of a cannula assembly 408. The heart pump assembly 400 includes a motor housing 402, an impeller blade 404, a catheter 428, a cannula assembly 408, a blood outlet 424, a plurality of openings 416, and an atraumatic tip 412. The cannula assembly 408 includes a cannula body 409 having a proximal end 411, a distal end 410, a distal end portion 414, a teardrop portion 442, a longitudinal axis 444, and a circumference 422. The motor housing 402 includes an impeller blade 404 that is rotatable relative to the cannula assembly 408. Rotation of the impeller blade 404 generates suction through the cannula assembly 408. Blood enters the cannula assembly 408 through a plurality of apertures 416 disposed at a distal end portion 414 of the cannula assembly 408. The plurality of apertures 416 are disposed around a circumference 422 of the cannula body 409 in a first ring 418 having apertures 418a-d, a second ring 420 having apertures 420a-d, and a third ring 430 having apertures 430a-d. The first ring 418 is proximal to the distal end 410 of the cannula assembly 408. The second ring 420 is proximal to the first ring 418, and the third ring 430 is proximal to the second ring 420. The plurality of apertures 416 are separated by a plurality of struts 217a-c. An atraumatic tip 412 is attached to the distal end 410 of the teardrop portion 442 of the cannula assembly 408.

[0035] Each of the plurality of openings 416 has a height, a width, and an area. The plurality of openings 416 can have a variety of sizes. The first ring 418 can have an opening 418d that has a larger area than the opening 420d of the second ring or the opening 430d of the third ring 430. The area of ​​the opening 418d of the first ring 418 can be 20 mm 2 In some embodiments, the area of ​​the opening 418d of the first ring 218 may be less than 0.5 mm 2 , 1mm 2 , 5mm 2 , 10mm 2 , 15mm 2 , 18mm 2 , 20mm 2 , 23mm 2 , 25mm 2 or any other suitable area. The area of ​​the opening 420d of the second ring 420 is 12 mm 2 In some embodiments, the area of ​​the opening 420d of the second ring 420 may be less than 0.25 mm 2 , 0.5mm 2 , 1mm 2 , 2mm 2 , 5mm 2 , 10mm 2 , 12mm 2or any other suitable area. The area of ​​the opening 430d of the third ring 430 may be the same as the area of ​​the opening 420d of the second ring. The height of the opening 418b of the first ring 418 measured along an axis parallel to the longitudinal axis 444 of the cannula assembly 408 may be less than 9 mm. In some embodiments, the height of the opening 418b of the first ring 418 may be 0.5 mm, 1 mm, 3 mm, 5 mm, 6 mm, 9 mm, 10 mm, 12 mm, 15 mm, or any other suitable height. The height of the opening 420b of the second ring 420 measured along an axis parallel to the longitudinal axis 444 of the cannula assembly 408 may be less than 3 mm. In some embodiments, the height of the opening 420b of the second ring 420 measured along an axis parallel to the longitudinal axis 444 of the cannula assembly 408 may be 0.25 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 5 mm, 6 mm, or any other suitable height. The width of the opening 420b in the second ring 420 measured transversely to the longitudinal axis 444 can be less than 4 mm. In some embodiments, the width of the opening 420b in the second ring 420 is 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 5 mm, 6 mm, 8 mm, or any other suitable width. In some embodiments, the height and width of the opening 430b are the same as the height and width of the opening 420b.

[0036] The multiple openings 416 prevent the heart pump assembly 400 from failing due to the valve leaflets sucking into a portion of the multiple openings 416. The multiple openings 416 located in the rings 418, 420, and 430 reduce the tendency of the multiple openings 416 to suck heart structures into the inlet of the heart pump assembly 400. The multiple openings 416, along with the struts 417a-c, prevent the heart pump assembly 400 from sucking the valve leaflets into the multiple openings 416, thereby reducing the risk of the openings 416 becoming blocked and allowing the heart pump assembly 400 to continue providing support to the heart. Additionally, the multiple openings 416 provide redundant inlets for blood to enter even if one or more of the multiple openings 416 become blocked by valve leaflets or other tissue.

[0037] In some embodiments, a large portion of blood entering the cannula assembly 408 enters through the most proximal of the plurality of openings 416, for example through openings 430a-c of the third ring 430. If one or more of the plurality of openings 416 in the third ring 430 are blocked, more blood may enter through the plurality of openings 416 in the second ring 420 or the first ring 418. The additional openings provide additional inlets through which blood can pass as it enters the heart pump assembly. Additionally, the struts 417a-c that define the plurality of openings 416 act as a shield to prevent tissue from being sucked into or out of the heart pump assembly 400.

[0038] Although Fig. 4 shows a heart pump assembly 400 having a plurality of apertures arranged in three rings, in some embodiments there may be additional rings of apertures. For example, Fig. 5 shows a perspective view of a distal end portion 514 of a cannula assembly having four rings of apertures, and Fig. 6 shows a front view of the distal end portion 514 of the cannula assembly of Fig. 5. The distal end portion 514 includes a distal end 510, an atraumatic tip connector 548, a teardrop portion 542, a longitudinal axis 544, and a plurality of apertures 516 arranged in a first ring 518, a second ring 520, a third ring 530, and a fourth ring 540. The plurality of apertures 516 in the first ring 518 includes apertures 518a-e oriented radially around the circumference of the distal end portion 514. The second ring 520 of apertures 520a-e, the third ring 530 of apertures 530a-e and the fourth ring 540 of apertures 540a-e are oriented radially around the distal end portion 514.

[0039] The first ring 518 of apertures 518a-e has the greatest height of the four rings of apertures. The first ring 518 of apertures 518a-e has a distal edge 551 of each aperture defined by a portion 552 of the teardrop portion 542. The teardrop portion 542 may be manufactured separately from the remainder of the cannula assembly in which the remainder of the plurality of apertures 516 are disposed and may be joined to the cannula assembly (not shown) as part of the manufacturing process. As a result, the first ring 518 of apertures 518a-e may be formed in the cannula assembly (or in the inflow cage, not shown) during the manufacturing process with only three sides initially defined and the fourth distal side open. Thereafter, when joined to the cannula assembly, the fourth distal edge 551 of each aperture 518a-e is defined by a portion 552 of the teardrop portion 542. The proximal edges 553 of the openings 518a-e are rounded, giving the openings 518a-e an oval shape.

[0040] The apertures 520a-e of the second ring 520 are rotationally offset from the apertures 518a-e of the first ring, such that a line 555 drawn through the center of aperture 518b, parallel to the longitudinal axis 544 of the distal end portion 514, does not pass through the center of any of the apertures 520a-e of the second ring 520. In some embodiments, the line 555 may pass through a portion of one of the apertures 520a-e, but not through the center of the apertures 520a-e. The apertures 530a-e are rotationally aligned with the apertures 518a-e, such that the line 555 passes through the center of one of the apertures 518a-e and the center of one of the apertures 530a-e. In particular, the line 555 passes through the center of the aperture 518b and the center of the aperture 530b. The apertures 540a-e are rotationally offset from the apertures 518a-e and apertures 530a-e such that line 555 does not pass through the center of any of the apertures 540a-e of the fourth ring 540. The apertures 520a-e of the second ring 520 are rotationally aligned with the apertures 540-e of the fourth ring 540, and a line 557 parallel to the longitudinal axis 544 of the distal end portion 514 passes through the centers of the apertures 520b and 540b. In some embodiments, different rings of apertures may be rotationally aligned or offset. For example, in some embodiments, the apertures 518a-e of the first ring 518 and the apertures 520a-e of the second ring 520 may be rotationally aligned, respectively, but the apertures 530a-e of the third ring 530 and the apertures 540a-e of the fourth ring 540 are not rotationally aligned with the first ring 518 and the second ring 520. In some embodiments, apertures 518a-e and apertures 530a-e are aligned, and apertures 520a-e and apertures 540a-e are rotationally offset from the first ring 518 and the third ring 530. In some embodiments, the second ring 520 and the fourth ring 540 are rotationally offset from the first ring 518 by different amounts, such that a line 557 drawn through aperture 520b in the second ring 520 does not pass through the center of any of the apertures 540a-e in the fourth ring 540.

[0041] Each of the apertures 518a-e, 520a-e, 530a-e, and 540a-e of the plurality of apertures 516 has a corresponding height measured parallel to a longitudinal axis 544, a width measured transverse to the longitudinal axis 544, and an area. For example, aperture 518a has a height 538 and a width 541. Aperture 518a also has an area 532 through which blood may pass. Aperture 520b of the second ring 520 has a height 554, a width 556, and an area 534. Aperture 530b of the third ring 530 has a height 558, a width 560, and an area 536. Aperture 540b of the fourth ring 540 has a height 562, a width 564, and an area 566. In some embodiments, measurements including one or more of the height, width, and area of ​​the apertures in a particular ring are common to all apertures in that ring, although this is not required. In some embodiments, measurements including one or more of height, width, and area vary between the openings in a particular ring. In some embodiments, the openings 520a-e in the second ring 520, the openings 530a-e in the third ring 530, and the openings 540a-e in the fourth ring 540 have the same measurements including one or more of height, width, and area. In some embodiments, one or more of the height, width, or area of ​​the openings vary between the openings 520a-e in the second ring 520, the openings 530a-e in the third ring 530, and the openings 540a-e in the fourth ring 540. In some embodiments, the combined areas of the openings 518a-e in the first ring 518, the openings 520a-e in the second ring 520, the openings 530a-e in the third ring 530, and the openings 540a-e in the fourth ring 540 are equal to or greater than the cross-sectional area of ​​the cannula assembly.

[0042] Even though the openings 518a-e in the first ring 518 have a larger area 532 than the openings 520a-e in the second ring 520, the openings 530a-e in the third ring 530, and the openings 540a-e in the fourth ring 540, blood flows primarily through the most proximal openings of the plurality of openings 516 due to the smaller pressure drop at the most proximal openings of the plurality of openings 516. Even if all or a portion of the openings 540a-e in the fourth ring 540 are blocked by valve leaflets, blood may still flow through the remaining openings. The smaller areas of the openings 520a-e in the second ring 520, the openings 530a-e in the third ring 530, and the openings 540a-e in the fourth ring 540, as well as the struts 517a-c between the openings, reduce the likelihood that additional inlets will be blocked by the valve leaflets.

[0043] 7 shows a front view of a distal end portion 714 of a cannula assembly 708 having a plurality of apertures 716 arranged in two rotationally offset rings. The cannula assembly 708 includes a cannula body 709, a distal end portion 714, a distal end 710, an atraumatic tip 712, a teardrop portion 742, a longitudinal axis 744, a plurality of struts 717a-c, and a plurality of apertures 716. The plurality of apertures 716 are arranged in a first ring 718 of apertures 718a-b and a second ring 720 of apertures 720a-b. The plurality of apertures 716 in the cannula assembly 708 are arranged such that the first ring 718 of apertures 718a-b is rotationally offset from the second ring 720 of apertures 720a-b. A line 755 drawn parallel to the longitudinal axis 744 of the cannula assembly 708 and passing through the center of the aperture 718a of the first ring 718 does not pass through the center of any of the apertures 720a-b of the second ring 720. Instead, the line 755 passes through a strut 717b that divides the apertures 720a and 720b of the second ring 720. The rotationally offset apertures may prevent the valve leaflets from completely blocking more than one of the apertures. For example, if a valve leaflet is attracted to the cannula assembly 708 and covers the aperture 718a of the first ring 718, the rotational offset of the apertures 720a-b of the second ring 720 may prevent the valve leaflet from blocking all of the additional apertures 720a or 720b of the second ring 720.

[0044] While Figures 5, 6 and 7 show a distal end portion of a cannula assembly (e.g., distal end portion 514 of Figure 5 or distal end portion 714 of Figure 7) having rotationally offset apertures (e.g., multiple apertures 516 of Figure 5 or multiple apertures 716 of Figure 7), Figure 8 shows a perspective view of distal end portion 814 of cannula assembly 808 in which multiple apertures 816 are rotationally aligned with one another. Figure 9 shows an alternative perspective view of distal end portion 914 having multiple rotationally aligned apertures 916. Cannula assembly 908 includes a cannula body 909, a distal end portion 914, a distal end 910, an atraumatic tip 912, a teardrop portion 942, an atraumatic tip connector 948, a longitudinal axis 944 and multiple apertures 916. The plurality of apertures 916 are disposed in a first ring 918 of apertures 918a-d and a second ring 920 of apertures 920a-d. The plurality of apertures 916 in the cannula assembly 908 are disposed such that the first ring 918 of apertures 918a-d is rotationally aligned with the second ring 920 of apertures 920a-d. A line 955 drawn parallel to the longitudinal axis 944 of the cannula assembly 908 and passing through the center of the apertures 918b in the first ring 918 also passes through the center of the apertures 920b in the second ring 920. The apertures 918a-d and apertures 920a-d are shown with a height greater than their width, with the area of ​​each aperture 918a-d and 920a-d being defined by an oval through which blood may pass as it enters the cannula assembly 908. Rotationally aligned apertures may be easier to machine into the cannula assembly 908 than offset apertures.

[0045] FIG. 10 shows a front view of a distal end portion 1014 of a cannula assembly 1008 having a plurality of round apertures 1016 rotationally offset from one another. The cannula assembly 1008 of FIG. 10 includes a distal end 1010, a distal end portion 1014, an atraumatic tip connector 1048, a teardrop portion 1042, a longitudinal axis 1044, an atraumatic tip 1012, and a plurality of apertures 1016. The plurality of apertures 1016 are disposed in a first ring 1018 with apertures 1018a-c, a second ring 1020 with apertures 1020a-b, a third ring 1030 with apertures 1030a-c, and a fourth ring 1040 with apertures 1040a-b. The apertures 1018a-c in the first ring 1018 are oval in shape. In particular, the first ring 1018 of apertures 1018a-c has a rounded proximal edge 1053 and a distal edge 1051 defined by a portion of the teardrop portion 1042. The apertures 1020a-b in the second ring 1020, the apertures 1030a-c in the third ring 1030, and the apertures 1040a-b in the fourth ring 1040 are circular. The apertures 1018a-c in the first ring 1018 and the apertures 1030a-c in the third ring 1030 are rotationally aligned such that a line 1055 passing through the center of aperture 1018b passes through the center of aperture 1030b. Apertures 1020a-b in second ring 1020 and apertures 1040a-b in fourth ring 1040 are rotationally offset from apertures 1018a-c and apertures 1030a-c but are rotationally aligned with one another, and a line 1057 passing through the center of aperture 1020, parallel to longitudinal axis 1044 of cannula 1008, passes through the center of aperture 1040a. Multiple apertures 1016 having circular shapes arranged in a ring around the periphery of cannula assembly 1008 such that the apertures in each ring are rotationally offset from the apertures in the ring immediately above or below it, may reduce the likelihood of the valve leaflets blocking the multiple apertures.

[0046] While FIG. 10 illustrates a distal end portion 1014 of a cannula assembly 1008 having a first ring of apertures and three additional rings of round apertures, FIG. 11 illustrates a distal end portion 1114 of a cannula assembly having a first ring of apertures and only two additional rings of round apertures. The distal end portion 1114 of FIG. 11 includes a distal end 1110, an atraumatic tip connector 1148, a teardrop portion 1142, a longitudinal axis 1144, and a plurality of apertures 1116. The plurality of apertures 1116 are disposed in a first ring 1118 of apertures 1118a-d, a second ring 1120 of apertures 1120a-c, and a third ring 1130 of apertures 1130a-c. The apertures 1118a-e of the first ring 1118 are oval in shape with a distal edge 1151 defined by a portion 1152 of the teardrop portion 1142. The proximal edges 1153 of the apertures 1118a-e are rounded. The apertures 1120a-c in the second ring 1120 and the apertures 1130a-c in the third ring 1130 are circular. Similar to the plurality of apertures 1116 of FIG. 10, the rings of the plurality of apertures 1116 are rotationally offset. For example, the apertures 1118a-e in the first ring 1118 and the apertures 1130a-c in the third ring 1130 are rotationally aligned such that a line 1155 passing through the center of aperture 1118b passes through the center of aperture 1130a.

[0047] While Figures 10 and 11 show a distal end portion having a plurality of circular and oval shaped openings, Figure 12 shows a front view of a distal end portion 1214 of a cannula assembly having a plurality of openings 1216 where a first ring 1218 has teardrop shaped openings 1218a and the openings in the further rings are circular. The distal end portion 1214 includes a distal end 1210, an atraumatic tip connector 1248, a teardrop portion 1242, a longitudinal axis 1244 and a plurality of openings 1216. The plurality of openings 1216 are disposed in the first ring 1218 at openings 1218a, the second ring 1220 at openings 1220a-b and the third ring 1230 at openings 1230a. Although only one aperture 1218a and one aperture 1230a are visible in FIG. 12, there may be multiple apertures in each ring 1218, 1220, and 1230 radially disposed about the distal end 1214 of the cannula assembly. The aperture 1218c in the first ring 1218 is teardrop shaped with a rounded distal edge 1251 defined by a portion 1252 of the teardrop portion 1242 of the atraumatic tip connector 1248 and a pointed proximal edge 1253 in the direction of blood flow through the cannula. The second ring 1220 of apertures 1220a-b and the third ring 1230 of apertures 1230a are circular. In some embodiments, one or both of the second ring 1220 of apertures 1220a-b and the third ring 1230 of apertures 1230a are rotationally aligned with the first ring 1218 of aperture 1218a.

[0048] FIG 12 shows a first ring 1218 of teardrop shaped openings, while the openings in the other rings are circular, but in some embodiments, all of the openings are teardrop shaped. For example, FIG 13 shows a front view of a distal end portion 1314 having a teardrop shaped opening in the first ring 1318 and multiple teardrop shaped openings disposed in the second ring 1320 and the third ring 1330. The distal end portion 1314 includes a distal end 1310, an atraumatic tip connector 1348, a teardrop portion 1342, a longitudinal axis 1344, and multiple openings 1316 disposed in the first ring 1318 at opening 1318a, the second ring 1320 at openings 1320a-b, and the third ring 1330 at opening 1330a. Similar to FIG. 11, only one aperture 1218a and one aperture 1230a are visible in the first ring 1218 and the third ring 1230 in FIG. 12, although each ring may include multiple apertures disposed about the distal end portion 1214 of the cannula assembly. Similar to aperture 1218a of the first ring 1218 in FIG. 12, aperture 1318a in the first ring is teardrop shaped, having a rounded distal edge 1351 defined by the teardrop portion 1342 of the atraumatic tip connector 1348, and a proximal edge 1353 that is pointed along the longitudinal axis 1344. Apertures 1320a-b in the second ring 1320 and apertures 1330a-c in the third ring 1330 are also teardrop shaped, with each aperture having a rounded distal end and a pointed proximal end. Apertures that taper from larger openings at the distal end to pointed openings at the proximal end may promote blood flow through the openings and reduce stagnation of blood as it flows into the multiple openings 1316.

[0049] Varying the number and size of the apertures in the distal end portion can change the blood flow distribution into the cannula. Figures 14-23 show additional arrangements of apertures in the distal end portion of the cannula. All of the arrangements in Figures 14-23 show multiple apertures arranged in similar portions of the distal end portion of the cannula, but the apertures vary in shape, location and relative size. Figure 14 shows a front view of a particular embodiment of a heart pump assembly distal end portion 1414 having multiple apertures 1416 arranged into three rings of apertures. The distal end portion 1414 includes a distal end 1410, an atraumatic tip connector 1448, a teardrop portion 1442, a longitudinal axis 1444, multiple apertures 1416, a first circumferential strut 1463 and a second circumferential strut 1465. The circumferential struts 1463 and 1465 extend around the circumference of the distal end portion 1414 and divide the multiple apertures 1416 into rings of apertures. A plurality of apertures 1416 are disposed in the first ring 1418 at apertures 1418a-c, the second ring 1420 at apertures 1420a-c, and the third ring 1430 at apertures 1430a-c. A first circumferential strut 1463 separates the first ring 1418 from the second ring 1420. A second circumferential strut 1465 separates the second ring 1420 from the third ring 1430. The apertures 1418a-c are defined on one side by a teardrop portion 1442. The apertures 1418a-c in the first ring 1418 are oval shaped and each have a height greater than their width. The apertures 1420a-c in the second ring 1420 and the apertures 1430a-c in the third ring 1430 are oval shaped and each have a height greater than their width. Additionally, the openings 1420a-c of the second ring 1420 and the openings 1430a-c of the third ring 1430 have proximal edges that are rounded and distal edges that are straight.

[0050] 15 shows a front view of a distal end portion 1514 of a cannula assembly of a particular embodiment. The distal end portion 1514 includes a distal end 1510, an atraumatic tip connector 1548, a teardrop portion 1542, a longitudinal axis 1544, a plurality of apertures 1516, a first circumferential strut 1563, and a second circumferential strut 1565. The circumferential struts 1563 and 1565 extend around the circumference of the distal end portion 1514 and divide the plurality of apertures 1516 into rings of apertures. The plurality of apertures 1516 are arranged into three rings of apertures: a first ring 1518 of apertures 1518a-c, a second ring 1520 of apertures 1520a-c, and a third ring 1530 of apertures 1530a-c. The first circumferential strut 1563 divides the first ring 1518 from the second ring 1520. A second circumferential strut 1565 divides the second ring 1520 from the third ring 1530. The openings 1518a-c of the first ring 1518 are defined on one side by a teardrop portion 1542 and have a smaller height along the longitudinal axis 1544 than the openings 1418a-c of the first ring 1418 of FIG. 14. The size and shape of the openings 1520a-c and openings 1530a-c are the same as in FIG. 14. In addition, the first circumferential strut 1563 between the first ring 1518 and the second ring 1520 has a greater height along the longitudinal axis 1544 than the first circumferential strut 1463 dividing the first ring 1418 and the second ring 1420 of FIG. 14. This may provide additional non-stick area that may prevent sticking of the valve leaflets to the cannula assembly according to certain embodiments.

[0051] 16 shows a front view of a particular embodiment of a distal end portion 1614. The distal end portion 1614 includes a distal end 1610, an atraumatic tip connector 1648, a teardrop portion 1642, a longitudinal axis 1644, a plurality of apertures 1616, a first circumferential strut 1663, and a second circumferential strut 1665. The circumferential struts 1663 and 1665 extend around the circumference of the distal end portion 1614 and divide the plurality of apertures 1616 into rings of apertures. The plurality of apertures 1616 are arranged into three rings of apertures: a first ring 1618 of apertures 1618a-c, a second ring 1620 of apertures 1620a-c, and a third ring 1630 of apertures 1630a-c. The first circumferential strut 1663 divides the first ring 1618 from the second ring 1620. A second circumferential strut 1665 divides the second ring 1620 from the third ring 1630. The openings 1618a-c in the first ring 1618 are defined on one side by a teardrop portion 1642. The height of the openings 1618a-c in the first ring 1618 is less than the height of the openings 1518a-c in the first ring 1518 of FIG. 15. The size and shape of the openings 1620a-c and openings 1630a-c are the same as in FIGS. 14 and 15, but the height of the openings 1618a-c in the first ring 1618 is less than the height of the corresponding openings in FIGS. 14 and 15. In addition, the first circumferential strut 1663 dividing the first ring 1618 from the second ring 1620 in the arrangement of FIG. 16 has a greater height along the longitudinal axis 1644 than the corresponding circumferential struts 1463 and 1563 in FIG. 14 or 15.

[0052] 17 shows a front view of a distal end portion 1714 of a particular embodiment of a cannula assembly having a plurality of apertures 1716 arranged into two rings of apertures. The distal end portion 1714 includes a distal end 1710, an atraumatic tip connector 1748, a teardrop portion 1742, a longitudinal axis 1744, a plurality of apertures 1716, and a circumferential strut 1763. The circumferential strut 1763 extends around the distal end portion 1714 and divides the plurality of apertures 1716 into rings of apertures. The plurality of apertures 1716 are arranged in a first ring 1718 of apertures 1718a-c and a second ring 1720 of apertures 1720a-c. The circumferential strut 1763 divides the first ring 1718 from the second ring 1720. The shape of the openings 1718a-c in the first ring 1718 may be oval with a distal edge 1751 defined by a teardrop portion 1742, as in FIGS. 14-16. The size and shape of the openings 1720a-c in the second ring 1720 may be the same as in FIGS. 14-16. The openings 1718a-c in the first ring 1718 and the openings 1720a-c in the second ring 1720 are shown offset from one another. However, in some embodiments, the openings 1718a-c in the first ring 1718 are rotationally aligned with the openings 1720a-c in the second ring 1720.

[0053] 18 shows a front view of a distal end portion 1814 of a particular embodiment of a cannula assembly having a plurality of apertures 1816 arranged into two rings of apertures. The distal end portion 1814 of the cannula 1808 includes a distal end 1810, an atraumatic tip connector 1848, a teardrop portion 1842, a plurality of apertures 1816, and a circumferential strut 1863. The circumferential strut 1863 extends around the distal end portion 1814 and divides the plurality of apertures 1816 into rings of apertures. The plurality of apertures 1816 are arranged into a first ring 1818 having apertures 1818a-c and a second ring 1820 having apertures 1820a-c. The circumferential strut 1863 divides the first ring 1818 from the second ring 1820. Openings 1818a-c in first ring 1818 are defined on one side by teardrop portion 1842 and have a smaller height than openings 1718a-c in the distal end portion of FIG. 17. The area through which blood can pass as it enters cannula assembly 1808 may be reduced in FIG. 18 compared to FIG. 17. However, circumferential struts 1863-1820 in FIG. 18 are larger than circumferential struts 1763 in FIG. 17. This increases the area where suction cannot occur and may reduce the chance of suctioning valve leaflets or other tissue into the cannula assembly.

[0054] 19-23 show various embodiment arrangements where the distal end portion includes a plurality of apertures arranged in four rings. For example, FIG. 19 shows a front view of a distal end portion 1914 of a cannula assembly. The distal end portion 1914 includes a distal end 1910, an atraumatic tip connector 1948, a teardrop portion 1942, a longitudinal axis 1944, a plurality of apertures 1916, a first circumferential strut 1963, a second circumferential strut 1965, and a third circumferential strut 1967. The circumferential struts 1963, 1965, and 1967 extend around the circumference of the distal end portion 1914 and divide the plurality of apertures 1916 into rings of apertures. A plurality of apertures 1916 are disposed in a first ring 1918 at apertures 1918a-c, a second ring 1920 at apertures 1920a-c, a third ring 1930 at apertures 1930a-c, and a fourth ring 1940 at apertures 1940a-c. A first circumferential strut 1963 separates the first ring 1918 from the second ring 1920. A second circumferential strut 1965 separates the second ring 1920 from the third ring 1930. A third circumferential strut 1967 separates the third ring 1930 from the fourth ring 1940. Apertures 1918a-c are bounded on one side by a teardrop portion 1942. The openings 1918a-c in the first ring 1918, the openings 1920a-c in the second ring 1920, the openings 1930a-c in the third ring 1930, and the openings 1940a-c in the fourth ring 1940 are similar in height. The first circumferential strut 1963 has a similar height as the second circumferential strut 1965, which is also similar to the height of the third circumferential strut 1967. The area of ​​the openings 1918a-c in the first ring 1918 is similar to the area of ​​the openings 1920a-c in the second ring 1920, the openings 1930a-c in the third ring 1930, and the openings 1940a-c in the fourth ring 1940. Although the openings in the second ring 1920, the third ring 1930 and the fourth ring 1940 are shown aligned with the openings 1918a-c in the first ring, in some embodiments the openings can be rotationally offset.

[0055] 20 illustrates a front view of a distal end portion 2014 of a particular embodiment of a cannula assembly 2008 having a plurality of apertures 2016 with each ring of apertures having a different size and shape. The distal end portion 2014 includes a distal end 2010, an atraumatic tip connector 2048, a teardrop portion 2042, a longitudinal axis 2044, and a plurality of apertures 2016. The plurality of apertures 2016 are disposed in a first ring 2018 with apertures 2018a-c, a second ring 2020 with apertures 2020a-b, a third ring 2030 with apertures 2030a-b, and a fourth ring 2040 with apertures 2040a-b. The apertures 2018a-c are defined on one side by the teardrop portion 2042. The apertures 2018a-c of the first ring 2018 have a maximum height of the plurality of apertures 2016. The apertures 2020a-b of the second ring 2020 have the next greatest height. The apertures 2030a-b of the third ring 2030 have the next greatest height. The apertures 2040a-b of the fourth ring 2040 have the smallest height of the plurality of apertures 2016. Although the plurality of apertures 2016 are shown having a rounded shape, the plurality of apertures 2016 may have any suitable shape while maintaining the relationship between the heights. In some embodiments, the height of the apertures 2018a-c of the first ring 2018 is less than six times the height of the apertures 2020a-b of the second ring 2020. In some embodiments, the height of the apertures 2020a-b of the second ring 2020 is less than three times the height of the apertures 2030a-b of the third ring 2030. In some embodiments, the height of the openings 2030a-b in the third ring 2030 is less than five times the height of the openings 2040a-b in the fourth ring 2040.

[0056] In each of Figures 21-22, the openings in the first ring have the same oval shape and the same size, and the openings in the second, third and fourth rings have the same size and shape. In Figure 21, the distal end portion 2114 includes a distal end 2110, an atraumatic tip connector 2148, a teardrop portion 2142, a longitudinal axis 2144 and a plurality of openings 2116. The plurality of openings 2116 are disposed in the first ring 2118 at openings 2118a-c, the second ring 2120 at openings 2120a-c, the third ring 2130 at openings 2130a-c and the fourth ring 2140 at openings 2140a-c. The openings 2118a-c in the first ring 2118 are oval shaped. In particular, the first ring 2118 of apertures 2118a-c has a rounded proximal edge 2153 and a distal edge 2151 defined by a portion 2152 of the teardrop portion 2142. The apertures 2120a-c in the second ring 2120 are the same shape and size as the apertures 2130a-c in the third ring 2130 and the apertures 2140a-c in the fourth ring 2140. The plurality of apertures 2116 in the second ring 2120, the third ring 2130 and the fourth ring 2140 are oval in shape and each have a width that is greater than its height measured along a line parallel to the longitudinal axis 2144. The plurality of apertures 2116 in the second ring 2120, the third ring 2130, and the fourth ring 2140 have rounded proximal edges 2169a-c, with the center of the proximal edges 2153 and 2169a-c being the most proximal point of each aperture. Each aperture has an inner edge 2171a-d. The inner edge 2171a-d of each of the plurality of apertures 2116 is chamfered. The chamfer can be at an angle of 45° or less with respect to a line perpendicular to the surface of the cannula assembly 108. In some embodiments, the chamfered inner edges 2171a-d include chamfers of 10°, 20°, 30°, 40°, 50°, >50°, or any other suitable angle. The use of chamfered inner edges 2171a-d can reduce hemolysis as blood enters the cannula assembly 2108. Although the chamfered inner edges 2171a-d are shown here in an arrangement having four rings of openings, the chamfered inner edges may be used in any of the arrangements shown herein.In FIG. 22, similar to FIG. 21, distal end portion 2214 includes distal end 2210, atraumatic tip connector 2248, teardrop portion 2242, longitudinal axis 2244, and a plurality of apertures 2216 disposed in a first ring 2218 of apertures 2218a-c, a second ring 2220 of apertures 2220a-c, a third ring 2230 of apertures 2230a-c, and a fourth ring 2240 of apertures 2240a-c. Each of the plurality of apertures 2216 has inner edges 2271a-d that are rounded. In some embodiments, the rounded inner edges 2271a-d include a radius of curvature that is in the range of 40 microns to 105 microns. In some embodiments, only the outwardly facing portions of inner edges 2271a-d are rounded. In some embodiments, the rounding of inner edges 2271a-d is achieved by grinding. In some embodiments, the rounding of the inner edges 2271a-d is achieved by a tumbling process. The rounded edges may reduce hemolysis as blood enters the cannula assembly 2208 through the plurality of openings 2216. Although the rounded inner edges 2271a-d are shown here in an arrangement having four rings of openings, the rounded inner edges may be used in any of the arrangements shown herein.

[0057] 23 shows a front view of the distal end portion 2314 of the cannula assembly. The distal end portion 2314 includes a distal end 2310, an atraumatic tip connector 2348, a teardrop portion 2342, a longitudinal axis 2344, and a plurality of apertures 2316. The plurality of apertures are disposed in a first ring 2318 of apertures 2318a-c, a second ring 2320 of apertures 2320a-c, a third ring 2330 of apertures 2330a-c, and a fourth ring 2340 of apertures 2340a-c. The apertures 2318a-c in the first ring 2318 have an oval shape with a distal edge 2351 defined by the teardrop portion 2342. The multiple openings 2320a-c, 2330a-c, and 2340a-c of the second ring 2320, the third ring 2330, and the fourth ring 2340, respectively, are elliptical in shape with a width greater than its height, and all of the multiple openings of the second ring 2320, the third ring 2330, and the fourth ring 2340 are the same size.

[0058] FIG. 24 shows a plot 2400 illustrating the predicted flow rate of fluid through multiple openings for the arrangement of FIG. 23. Plot 2400 includes a cutaway view of distal end portion 2414 of the cannula assembly, second opening 2420, fourth opening 2440, and a box 2441 showing a high flow area. The plot shows the predicted flow rate of fluid through two openings of a heart pump shown in cross section. The heart pump has first, second, third and fourth rings of openings, although in the illustrated embodiment, first ring 2418 and third ring 2430 are rotationally offset so that only the openings of second ring 2420 and fourth ring 2440 are visible. In the plot, areas of higher velocity are shown with longer lines and areas of lower flow are shown with fewer lines. The magnitude of the velocity of the fluid flow is 1.28×e -05 The flow rates range from approximately 0 m / s to 6.08 m / s. The greatest volumetric flow rate (highlighted by box 2441) occurs at the most proximal opening, in this case opening 2440a of the fourth ring 2440. The high flow rate of fluid into the cannula assembly 2408 at this point is due to the relatively high pressure gradient at this opening. Blood is drawn from outside the cannula assembly 2408 through the opening and into the cannula assembly 2408 where it flows to a downstream opening (not shown).

[0059] 25 shows a percutaneous heart pump assembly 2500 having a plurality of openings 2516 at a distal end portion 2514 inserted into a patient's blood vessel 2501. In particular, the heart pump assembly 2500 is introduced through the patient's blood vessel 2501 into a heart 2503. The heart 2503 includes an aorta 2568, an aortic arch 2577, an aortic valve 2570, a left ventricle 2572, a left atrium 2576, and a mitral valve 2574, as well as other structures. The heart pump assembly 2501 includes a catheter 2528, a motor housing 2502, a cannula assembly 2508, a cannula body 2509, a distal end portion 2514, a proximal end 2506, a distal end 2510, an atraumatic tip 2512, a plurality of openings 2516, and a plurality of blood outlets 2524. The motor housing 2502 of the heart pump assembly 2500 is connected to a motor (not shown). The motor is internal to and integral with the motor housing 2502. In other embodiments, the motor is external to the body and connected to the pump via a drive shaft (not shown) in the catheter 2528, and in such instances, the assembly 2508 may not include the motor housing 2502. The cannula assembly 2508 is connected to a distal end of the motor housing 2502. The distal end portion 2514 of the cannula assembly 2508 includes a plurality of apertures 2516 through which blood may enter the cannula assembly 2508. The plurality of apertures 2516 are arranged into at least a first ring 2518 and a second ring 2520 of apertures that are radially oriented and arranged around the circumference of the cannula assembly 2508. Although two rings of apertures are shown here, any arrangement of apertures described herein may be used. In some embodiments, the plurality of apertures 2516 are arranged into three, four or more rings of apertures. The atraumatic tip 2512 is coupled to a distal end 2510 of the cannula assembly 2508, distal to a plurality of openings 2516. Blood is drawn into the cannula assembly 2508 from the plurality of openings 2516 along a pathway 2578. The blood passes through the cannula assembly 2508 and exits along a pathway 2580 from a plurality of blood outlets 2524 proximal to the motor housing 2502.

[0060] The heart pump assembly 2500 may be percutaneously introduced through the vascular system during a cardiac procedure. Specifically, the heart pump assembly 2500 may be percutaneously inserted through a catheter insertion procedure, through the femoral artery, into the ascending aorta 2568, past the aortic valve 2570, and into the left ventricle 2572. The heart pump assembly 2500 may be positioned in the patient's heart 2503 such that it is inserted above the aortic arch 2577. The blood outlets 2524 may be positioned in the aorta 2568, above the aortic valve 2570. The cannula assembly 2508 is positioned to pass through the aortic valve 2570 such that the openings 2516 through which blood enters are positioned in the left ventricle 2572 of the heart 2503. The atraumatic tip 2512 spaces the cannula assembly 2508 away from the wall of the heart 2503 and prevents the openings 2516 from sticking to the wall of the heart 2503.

[0061] However, in some cases, the arrangement of the heart pump assembly 2501 positions the multiple openings 2516 near the mitral valve leaflets 2574 at the entrance to the left atrium 2576. This may be due to the individual anatomical structure of the particular heart 2503. The mitral valve leaflets 2574 may be sucked into the multiple openings 2516 by the pump suction and may be sucked into some of the multiple openings 2516, blocking the inflow of blood through the multiple openings 2516. In some cases, especially in pumps with large inlets, such as the heart pump assembly 100 of FIG. 1, the mitral valve leaflets 2574 may be sucked into the cannula assembly 2508 through one of the multiple openings 2516, where they block the flow of blood through the cannula. The smaller size of the multiple openings 2516 prevents the mitral valve leaflets from being sucked into the multiple openings 2516. Furthermore, the multiple openings 2516 allow blood flow through the cannula assembly 2508 to be maintained despite the adhesion of the mitral valve leaflets 2574 or other tissue or tissue debris to some of the multiple openings 2516. In another embodiment (not shown), the heart pump assembly may be designed to support the right heart of a patient. In certain aspects, the device may be inserted percutaneously through the femoral vein into the right atrium or by other techniques. When the device is so positioned, the cannula of the assembly may extend through the tricuspid valve and the pulmonary valve into the pulmonary artery. In this case, the multiple openings may be positioned at the inlet of the pump positioned in the inferior vena cava (IVC). As will be appreciated, such a device may include any of the configurations of the openings described above. The device may or may not include an atraumatic tip or protrusion.

[0062] FIG. 26 is a flow chart of a method of manufacturing a particular embodiment heart pump having multiple openings at a distal end portion (e.g., heart pump assembly 200 of FIG. 2, heart pump assembly 400 of FIG. 4, heart pump assembly 2500 of FIG. 25, or any other suitable heart pump). Method 2600 may be performed to form a heart pump having any number of openings arranged in any number of rings at the distal end portion. Method 2600 may be performed for the manufacture of heart pump assemblies having openings of any size or shape with straight, chamfered, or rounded edges. At step 2602, an impeller blade is coupled to the rotor of a motor. The impeller blade may have any suitable number of blades and may be turned by a drive shaft coupled to the motor. In some embodiments, the motor is configured to be external to the patient during operation of the pump. In some embodiments, the motor is integral with the motor housing. At step 2604, the impeller blade is inserted into the motor housing. At step 2606, a cannula is coupled to the motor housing. The cannula may be attached to the distal end of the motor housing. In some embodiments, the cannula is expandable. In some embodiments, the cannula is self-expanding. In some embodiments, the cannula may be comprised of a mesh, such as a nitinol mesh, covered by an elastic covering. In some embodiments, the cannula may be comprised of a solid wire, such as a nitinol wire with a polymer covering or fabric.

[0063] At step 2608, the cannula is coupled to an inflow cage that includes a plurality of apertures. In some embodiments, the inflow cage is constructed of stainless steel. The plurality of apertures may be of any number, shape, or size suitable for blood to pass through the apertures in the inflow cage and enter the cannula. The plurality of apertures are oriented radially around the circumference of the inflow cage. The plurality of apertures are arranged into at least a first ring of apertures and a second ring of apertures proximal to the first ring of apertures. The number of apertures in a ring is 3, 4, 5, 6, 7, 8, 9, 10, or any other suitable number of apertures. In some embodiments, the number of apertures in the first ring is the same as the number of apertures in the second ring. The first ring of apertures extends to the end of the distal end portion of the inflow cage. In some embodiments, the plurality of apertures further includes more rings, for example, a third ring proximal to the second ring and a fourth ring proximal to the third ring. Each of the plurality of apertures may have an outer edge that is formed or deformed in some embodiments by a tumbling process.

[0064] The multiple openings may have a size, shape, number, or arrangement that helps prevent cardiac tissue, including valve leaflets, from being sucked into or sucked into the multiple openings (which would block blood flow to the pump and limit the efficiency of the heart pump). For example, in some embodiments, the height of the first opening is less than 9 mm. In some embodiments, the height of the openings in the first ring is 0.5 mm, 1 mm, 3 mm, 5 mm, 6 mm, 9 mm, 10 mm, 12 mm, 15 mm, or any other suitable height. In some embodiments, the height of the second opening is less than 3 mm. In some embodiments, the height of the openings in the second ring is 0.25 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 5 mm, 6 mm, or any other suitable height. In some embodiments, the width of the second opening is less than 4 mm. In some embodiments, the width of the opening in the second ring is 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 5 mm, 6 mm, 8 mm, or any other suitable width. In some embodiments, the height and width of the opening in the third ring are the same as the height and width of the opening in the second ring.

[0065] The area of ​​each opening may vary. In some embodiments, the area of ​​the opening in the first ring is larger than the area of ​​the opening in the other ring. In some embodiments, the area of ​​the first opening is 20 mm 2 In some embodiments, the area of ​​the opening in the first ring is less than 0.5 mm 2 , 1mm 2 , 5mm 2 , 10mm 2 , 15mm 2 , 18mm 2 , 20mm 2 , 23mm 2 , 25mm 2 or any other suitable area. Area of ​​the opening in the second ring: 12 mm 2 In some embodiments, the area of ​​the opening in the second ring may be less than 0.25 mm 2 , 0.5mm 2 , 1mm2 , 2mm 2 , 5mm 2 , 10mm 2 , 12mm 2 or any other suitable area.

[0066] The openings may have straight, rounded, or chamfered inner edges. In some embodiments, the openings have at least one chamfered edge. The chamfer may be at an angle of 45° or less to a line perpendicular to the surface of the inflow cage. In some embodiments, the chamfered inner edges include chamfers of 10°, 20°, 30°, 40°, 50°, >50°, or any other suitable angle. The use of chamfered inner edges can reduce hemolysis as blood enters the inflow cage. In some embodiments, the openings have at least one rounded edge. In some embodiments, the rounded inner edges include a radius of curvature that ranges from 40 microns to 105 microns.

[0067] In some embodiments, the plurality of openings is formed in the distal end portion of the cannula. In some embodiments, the distal end portion of the cannula is constructed of stainless steel. The plurality of openings formed in the cannula can be of any number, shape, or size suitable for blood to pass through the openings and enter the cannula. The plurality of openings can be oriented radially around the circumference of the cannula. The plurality of openings is arranged into at least a first ring of openings and a second ring of openings proximal to the first ring of openings. The number of openings in the ring is 3, 4, 5, 6, 7, 8, 9, 10, or any other suitable number of openings. In some embodiments, the number of openings in the first ring is the same as the number of openings in the second ring. The first ring of openings extends to the end of the distal end portion of the cannula. In some embodiments, the plurality of openings further includes more rings, such as a third ring proximal to the second ring and a fourth ring proximal to the third ring. Each of the plurality of openings can have an outer edge that is formed or deformed in some embodiments by a tumbling process.

[0068] At step 2610, a distal projection is coupled to a distal end of the inflow cage. The distal projection or atraumatic tip is distal to the plurality of apertures. The base of the distal projection may form a distal edge of the plurality of apertures in the first ring of apertures. In some embodiments, this step is optional and the distal projection is not attached to the heart pump. In some embodiments, the distal projection is configured as a pigtail. In some embodiments, the distal projection is configured as a flexible projection or extension. The distal projection is an atraumatic tip configured to space the plurality of apertures on the inflow cage from the wall of the heart. In some embodiments, the distal projection includes a lumen into which a guidewire may be inserted. The distal projection provides a mechanical extension of the cannula to prevent the plurality of apertures from sticking to the tissue of the heart.

[0069] FIG. 27 shows a flow chart of a method of use of a heart pump having multiple openings at a distal end portion (e.g., heart pump assembly 200 of FIG. 2, heart pump assembly 400 of FIG. 4, heart pump assembly 2500 of FIG. 25, or any other suitable heart pump). Method 2700 may be implemented to form a heart pump having any number of openings at a distal end portion arranged in any number of rows. Method 2700 may be implemented for use with heart pump assemblies having openings of any size or shape with straight, chamfered, or rounded edges. At step 2702, a pump motor is used to rotate an impeller about an axis of rotation to draw blood from multiple blood inlet openings into a cannula of the blood pump assembly. The motor may be external to the patient and connected to the impeller by a drive shaft. Alternatively, the motor may be built into the pump and used internally. The blood inlet openings may have any size, shape, or number. The blood inlet openings are oriented radially around the cannula and arranged in at least two rings at the distal end portion of the cannula. The size, shape, number and location of the blood inlet openings can be configured to reduce the occurrence of aspirating cardiac tissue, valve leaflets and other tissue debris that obstructs the inlet openings.

[0070] At step 2704, blood is discharged from the heart pump assembly through a plurality of blood discharge openings located at a proximal end portion of the cannula proximal to the motor housing. Blood may be drawn into the cannula from a blood inlet opening in the left ventricle and discharged from the blood outlet opening into the aorta over the aortic valve. The plurality of small inlet openings prevents or reduces the tendency of the openings to stick to heart structures or valve leaflets. The small openings prevent the pump from sucking leaflets into the inlet, reducing potential damage to heart structures that may be sucked by the pump, allowing the pump to provide more support to the heart.

[0071] The foregoing is merely illustrative of the principles of the present disclosure, and the device may be practiced in other than the above embodiments presented for purposes of illustration and not limitation. It will be appreciated that while the device disclosed herein is shown for use in a percutaneous heart pump, it may also be applied to devices in other applications requiring an empty opening for inflow.

[0072] Variations and modifications will occur to those skilled in the art after considering this disclosure. The disclosed features may be embodied in any combination and subcombination (including multiple subcombinations and subcombinations) with one or more other features described herein. The various features may be combined or integrated into other systems, including any of their components. Moreover, certain features may be omitted or not embodied.

[0073] Examples of modifications, substitutions and variations are ascertainable by one skilled in the art and can be made without departing from the scope of the information disclosed herein. All references cited herein are incorporated by reference in their entirety and made part of this application.

Claims

1. A rotor, a motor coupled to the rotor; impeller blades coupled to the rotor such that rotation of the rotor rotates the impeller blades and propels blood; A catheter; a cannula assembly including a cannula body and a blood inlet including a plurality of openings oriented and disposed radially around a periphery of the blood inlet; 1. A heart pump assembly configured for percutaneous insertion, comprising: the plurality of openings includes at least a first row of openings linearly spaced about the fixed outer perimeter of the blood inlet and a second row of openings spaced laterally from the first row of openings on the fixed outer perimeter of the blood inlet, the second row of openings being proximal to the first row of openings such that the second row of openings is closer to the catheter than the first row of openings; the apertures in the first row of apertures are oval and rotationally offset from the apertures in the second row of apertures, the apertures in the second row of apertures being circular; Heart pump assembly.

2. 2. The heart pump assembly of claim 1, wherein a first opening in the first row of openings and a second opening in the second row of openings are not aligned along an axis on the surface of the cannula body that is parallel to a longitudinal axis of the cannula body.

3. 2. The heart pump assembly of claim 1, wherein the openings in the first row of openings have rounded proximal edges and distal edges defined by a teardrop portion of the cannula assembly, the proximal edges being closer to the catheter than the distal edges.

4. 2. The heart pump assembly of claim 1, wherein the plurality of openings further includes a third row of openings, the third row of openings being proximal to the second row of openings so as to be closer to the catheter than the second row of openings.

5. The heart pump assembly of claim 4 , wherein the openings in the first row of openings are rotationally aligned with the openings in the third row of openings.

6. 5. The heart pump assembly of claim 4, wherein a first opening in the first row of openings and a third opening in the third row of openings are aligned along an axis on the surface of the cannula body parallel to a longitudinal axis of the cannula body.

7. The heart pump assembly of claim 4 , wherein the openings in the third row of openings are circular.

8. 5. The heart pump assembly of claim 4, wherein the plurality of openings further includes a fourth row of openings, the fourth row of openings being proximal to the third row of openings so as to be closer to the catheter than the third row of openings.

9. The heart pump assembly of claim 8 , wherein the openings in the fourth row of openings are circular.

10. The heart pump assembly of claim 8 , wherein the openings in the second row of openings are rotationally aligned with the openings in the fourth row of openings.

11. 9. The heart pump assembly of claim 8, wherein a second opening in the second row of openings and an opening in the fourth row of openings are aligned along an axis on the surface of the cannula body parallel to a longitudinal axis of the cannula body.

12. 11. The heart pump assembly of claim 10, wherein the openings in the second row of openings and the openings in the fourth row of openings are rotationally offset from the openings in the first row of openings and the openings in the third row of openings.

13. The heart pump assembly of any one of claims 1 to 12, wherein each of the plurality of openings is defined by an inner edge that intersects an interior of the cannula body and an outer edge that intersects an outer surface of the cannula body.

14. 13. The heart pump assembly of claim 1, wherein each of the plurality of openings is defined by an inner edge that intersects with an interior of the cannula body and an outer edge that intersects with an outer surface of the cannula body, and wherein the outer edge of each of the plurality of openings is chamfered.

15. The heart pump assembly of any one of claims 1 to 14, further comprising a distal protrusion coupled to a distal end of the cannula assembly.

16. The heart pump assembly of any one of claims 1 to 15, wherein the heart pump assembly is sized for percutaneous insertion.

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